Patent Publication Number: US-8542326-B2

Title: 3D shutter glasses for use with LCD displays

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 61/310,556, filed Mar. 4, 2010, the disclosure of which is incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 13/038,944, filed Mar. 2, 2011, and claims the benefit of the filing dates of U.S. provisional patent application No. 61/309,611, filed Mar. 2, 2010, the disclosures of which are all incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,518, filed Nov. 16, 2009, and claims the benefit of the filing dates of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, and U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, the disclosures of which are all incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,517, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,309, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,415, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,400, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,431, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,163, filed on Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/619,456, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, he disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of Ser. No. 12/619,102, filed Nov. 16, 2009, which claims the benefit of the filing date of U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, and the filing date of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 13/019,896, filed Feb. 2, 2011, which claims the benefit of the filing date of U.S. provisional patent application No. 61/285,071, filed Dec. 9, 2009, incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/748,185, filed Mar. 26, 2010, and U.S. utility patent application Ser. No. 12/880,920, filed Sep. 13, 2010, which claims the benefit of the filing date of U.S. utility patent application Ser. No. 12/619,518, filed Nov. 16, 2009, and claims the benefit of the filing dates of U.S. provisional patent application No. 61/179,248, filed May 18, 2009, and U.S. provisional patent application No. 61/115,477, filed Nov. 17, 2008, the disclosures of which are all incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/908,430, filed Oct. 20, 2010, which claims the benefit of the filing date of U.S. provisional patent application No. 61/253,150, filed Oct. 20, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/908,371, filed on Oct. 20, 2010, now abandoned, which claims the benefit of the filing date of U.S. provisional patent application No. 61/253,140, filed Oct. 20, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/947,619, filed Nov. 16, 2010, which claims the benefit of the filing date of U.S. provisional patent application No. 61/261,663, filed Nov. 16, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/963,812, filed Dec. 9, 2010, which claims the benefit of the filing date of U.S. provisional patent application No. 61/285,048, filed on Dec. 9, 2009, the disclosures of which are incorporated herein by reference. 
     This application is a continuation in part of U.S. utility patent application Ser. No. 12/963,373, filed on Dec. 8, 2010, which claims the benefit of the filing date of U.S. provisional patent application No. 61/285,071, filed on Dec. 9, 2009, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     This disclosure relates to image processing systems for the presentation of a video image that appears three dimensional to the viewer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of an exemplary embodiment of a system for providing three dimensional images. 
         FIG. 2  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 3  is a graphical illustration of the operation of the method of  FIG. 2 . 
         FIG. 4  is a graphical illustration of an exemplary experimental embodiment of the operation of the method of  FIG. 2 . 
         FIG. 5  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 6  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 7  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 8  is a graphical illustration of the operation of the method of  FIG. 7 . 
         FIG. 9  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 10  is a graphical illustration of the operation of the method of  FIG. 9 . 
         FIG. 11  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 12  is a graphical illustration of the operation of the method of  FIG. 11 . 
         FIG. 13  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 14  is a graphical illustration of the operation of the method of  FIG. 13 . 
         FIG. 15  is a flow chart of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 16  is an illustration of an exemplary embodiment of a method for operating the system of  FIG. 1 . 
         FIG. 17  is an illustration of an exemplary embodiment of the 3D glasses of the system of  FIG. 1 . 
         FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d  is a schematic illustration of an exemplary embodiment of 3D glasses. 
         FIG. 19  is a schematic illustration of the digitally controlled analog switches of the shutter controllers of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 20  is a schematic illustration of the digitally controlled analog switches of the shutter controllers, the shutters, and the control signals of the CPU of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 21  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 22  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 23  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 24  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 25  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 26  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 27  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 28  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIG. 29  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d.    
         FIGS. 30 ,  30   a ,  30   b  and  30   c  is a schematic illustration of an exemplary embodiment of 3D glasses. 
         FIG. 31  is a schematic illustration of the digitally controlled analog switches of the shutter controllers of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 32  is a schematic illustration of the operation of the digitally controlled analog switches of the shutter controllers of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 33  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 34  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 35  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 36  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 37  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 38  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 39  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 40  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 41  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 42  is a flow chart illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 43  is a graphical illustration of an exemplary embodiment of the operation of the 3D glasses of  FIGS. 30 ,  30   a ,  30   b  and  30   c.    
         FIG. 44  is a top view of an exemplary embodiment of 3D glasses. 
         FIG. 45  is a rear view of the 3D glasses of  FIG. 44 . 
         FIG. 46  is a bottom view of the 3D glasses of  FIG. 44 . 
         FIG. 47  is a front view of the 3D glasses of  FIG. 44 . 
         FIG. 48  is a perspective view of the 3D glasses of  FIG. 44   
         FIG. 49  is a perspective view of the use of a key to manipulate a housing cover for a battery for the 3D glasses of  FIG. 44 . 
         FIG. 50  is a perspective view of the key used to manipulate the housing cover for the battery for the 3D glasses of  FIG. 44 . 
         FIG. 51  is a perspective view of the housing cover for the battery for the 3D glasses of  FIG. 44 . 
         FIG. 52  is a side view of the 3D glasses of  FIG. 44 . 
         FIG. 53  is a perspective side view of the housing cover, battery and an O-ring seal for the 3D glasses of  FIG. 44 . 
         FIG. 54  a perspective bottom view of the housing cover, battery and the O-ring seal for the 3D glasses of  FIG. 44 . 
         FIG. 55  is a perspective view of an alternative embodiment of the glasses of  FIG. 44  and an alternative embodiment of the key used to manipulate housing cover of  FIG. 50 . 
         FIG. 56  is a schematic illustration of an exemplary embodiment of a signal sensor for use in one or more of the exemplary embodiments. 
         FIG. 57  is a graphical illustration of an exemplary data signal suitable for use with the signal sensor of  FIG. 56 . 
         FIG. 58  is a schematic illustration of an exemplary system for viewing 3D images. 
         FIG. 59  is a flow chart illustration of an exemplary method of operating the system of  FIG. 58 . 
         FIG. 60  is a schematic illustration of an exemplary system for viewing 3D images. 
         FIG. 61  is a schematic illustration of an exemplary embodiment of a method of operating the system of  FIG. 60 . 
     
    
    
     DETAILED DESCRIPTION 
     In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. 
     Referring initially to  FIG. 1 , a system  100  for viewing a three dimensional (“3D”) movie on a movie screen  102  includes a pair of 3D glasses  104  having a left shutter  106  and a right shutter  108 . In an exemplary embodiment, the 3D glasses  104  include a frame and the shutters,  106  and  108 , are provided as left and right viewing lenses mounted and supported within the frame. 
     In an exemplary embodiment, the shutters,  106  and  108 , are liquid crystal cells that open when the cell goes from opaque to clear, and the cell closes when the cell goes from clear back to opaque. Clear, in this case, is defined as transmitting enough light for a user of the 3D glasses  104  to see an image projected on the movie screen  102 . In an exemplary embodiment, the user of the 3D glasses  104  may be able to see the image projected on the movie screen  102  when the liquid crystal cells of the shutters,  106  and/or  108 , of the 3D glasses  104  become 25-30 percent transmissive. Thus, the liquid crystal cells of a shutter,  106  and/or  108 , is considered to be open when the liquid crystal cell becomes 25-30 percent transmissive. The liquid crystal cells of a shutter,  106  and/or  108 , may also transmit more than 25-30 percent of light when the liquid crystal cell is open. 
     In an exemplary embodiment, the shutters,  106  and  108 , of the 3D glasses  104  include liquid crystal cells having a PI-cell configuration utilizing a low viscosity, high index of refraction liquid crystal material such as, for example, Merck MLC6080. In an exemplary embodiment, the PI-cell thickness is adjusted so that in its relaxed state it forms a ½-wave retarder. In an exemplary embodiment, the PI-cell is made thicker so that the ½-wave state is achieved at less than full relaxation. One of the suitable liquid crystal materials is MLC6080 made by Merck, but any liquid crystal with a sufficiently high optical anisotropy, low rotational viscosity and/or birefringence may be used. The shutters,  106  and  108 , of the 3D glasses  104  may also use a small cell gap, including, for example, a gap of 4 microns. Furthermore, a liquid crystal with a sufficiently high index of refraction and low viscosity may also be suitable for use in the shutters,  106  and  108 , of the 3D glasses  104 . 
     In an exemplary embodiment, the Pi-cells of the shutters,  106  and  108 , of the 3D glasses  104  work on an electrically controlled birefringence (“ECB”) principle. Birefringence means that the Pi-cell has different refractive indices, when no voltage or a small catching voltage is applied, for light with polarization parallel to the long dimension of the Pi-cell molecules and for light with polarization perpendicular to long dimension, no and ne. The difference no−ne=Δn is optical anisotropy. Δn×d, where d is thickness of the cell, is optical thickness. When Δn×d=½λ the Pi-cell is acting as a ½ wave retarder when cell is placed at 45° to the axis of the polarizer. So optical thickness is important not just thickness. In an exemplary embodiment, the Pi-cells of the shutters,  106  and  108 , of the 3D glasses  104  are made optically too thick, meaning that Δn×d&gt;½λ. The higher optical anisotropy means thinner cell—faster cell relaxation. In an exemplary embodiment, when voltage is applied the molecules&#39; of the Pi-cells of the shutters,  106  and  108 , of the 3D glasses  104  long axes are perpendicular to substrates—homeotropic alignment, so there is no birefringence in that state, and, because the polarizers have transmitting axes crossed, no light is transmitted. In an exemplary embodiment, Pi-cells with polarizers crossed are said to work in normally white mode and transmit light when no voltage is applied. Pi-cells with polarizers&#39; transmitting axes oriented parallel to each other work in a normally black mode, i.e., they transmit light when a voltage is applied. 
     In an exemplary embodiment, when high voltage is removed from the Pi-cells, the opening of the shutters,  106  and/or  108 , start. This is a relaxation process, meaning that liquid crystal (“LC”) molecules in the Pi-cell go back to the equilibrium state, i.e. molecules align with the alignment layer, i.e. the rubbing direction of the substrates. The Pi-cell&#39;s relaxation time depends on the cell thickness and rotational viscosity of the fluid. 
     In general, the thinner the Pi-cell, the faster the relaxation. In an exemplary embodiment, the important parameter is not the Pi-cell gap, d, itself, but rather the product Δnd, where Δn is the birefringence of the LC fluid. In an exemplary embodiment, in order to provide the maximum light transmission in its open state, the head-on optical retardation of the Pi-cell, Δnd, should be λ/2. Higher birefringence allows for thinner cell and so faster cell relaxation. In order to provide the fastest possible switching fluids with low rotational viscosity and higher birefringence—Δn (such as MLC 6080 by EM industries) are used. 
     In an exemplary embodiment, in addition to using switching fluids with low rotational viscosity and higher birefringence in the Pi-cells, to achieve faster switching from opaque to clear state, the Pi-cells are made optically too thick so that the ½-wave state is achieved at less than full relaxation. Normally, the Pi-cell thickness is adjusted so that in its relaxed state it forms a ½-wave retarder. However, making the Pi-cells optically too thick so that the ½-wave state is achieved at less than full relaxation results in faster switching from opaque to clear state. In this manner, the shutters  106  and  108  of the exemplary embodiments provide enhanced speed in opening versus prior art LC shutter devices that, in an exemplary experimental embodiment, provided unexpected results. 
     In an exemplary embodiment, a catch voltage may then be used to stop the rotation of the LC molecules in the Pi-cell before they rotate too far. By stopping the rotation of the LC molecules in the Pi-cell in this manner, the light transmission is held at or near its peak value. 
     In an exemplary embodiment, the system  100  further includes a signal transmitter  110 , having a central processing unit (“CPU”)  110   a , that transmits a signal toward the movie screen  102 . In an exemplary embodiment, the transmitted signal is reflected off of the movie screen  102  towards a signal sensor  112 . The transmitted signal could be, for example, one or more of an infrared (“IR”) signal, a visible light signal, multiple colored signal, or white light. In some embodiments, the transmitted signal is transmitted directly toward the signal sensor  112  and thus, may not reflect off of the movie screen  102 . In some embodiments, the transmitted signal could be, for example, a radio frequency (“RF”) signal that is not reflected off of the movie screen  102 . 
     The signal sensor  112  is operably coupled to a CPU  114 . In an exemplary embodiment, the signal sensor  112  detects the transmitted signal and communicates the presence of the signal to the CPU  114 . The CPU  110   a  and the CPU  114  may, for example, each include a general purpose programmable controller, an application specific intergrated circuit (“ASIC”), an analog controller, a localized controller, a distributed controller, a programmable state controller, and/or one or more combinations of the aforementioned devices. 
     The CPU  114  is operably coupled to a left shutter controller  116  and a right shutter controller  118  for monitoring and controlling the operation of the shutter controllers. In an exemplary embodiment, the left and right shutter controllers,  116  and  118 , are in turn operably coupled to the left and right shutters,  106  and  108 , of the 3D glasses  104  for monitoring and controlling the operation of the left and right shutters. The shutter controllers,  116  and  118 , may, for example, include a general purpose programmable controller, an ASIC, an analog controller, an analog or digital switch, a localized controller, a distributed controller, a programmable state controller, and/or one or more combinations of the aforementioned devices. 
     A battery  120  is operably coupled to at least the CPU  114  and provides power for operating one or more of the CPU, the signal sensor  112 , and the shutter controllers,  116  and  118 , of the 3D glasses  104 . A battery sensor  122  is operably coupled to the CPU  114  and the batter  120  for monitoring the amount of power remaining in the battery. 
     In an exemplary embodiment, the CPU  114  may monitor and/or control the operation of one or more of the signal sensor  112 , the shutter controllers,  116  and  118 , and the battery sensor  122 . Alternatively, or in addition, one or more of the signal sensor  112 , the shutter controllers,  116  and  118 , and the battery sensor  122  may include a separate dedicated controller and/or a plurality of controllers, which may or may not also monitor and/or control one or more of signal sensor  112 , the shutter controllers,  116  and  118 , and the battery sensor  122 . Alternatively, or in addition, the operation of the CPU  114  may at least be partially distributed among one or more of the other elements of the 3D glasses  104 . 
     In an exemplary embodiment, the signal sensor  112 , the CPU  114 , the shutter controllers,  116  and  118 , the battery  120 , and the battery sensor  122  are mounted and supported within the frame of the 3D glasses  104 . If the movie screen  102  is positioned within a movie theater, then a projector  130  may be provided for projecting one or more video images on the movie screen. In an exemplary embodiment, the signal transmitter  110  may be positioned proximate, or be included within, the projector  130 . In an exemplary embodiment, the projector  130  may include, for example, one or more of an electronic projector device, an electromechanical projector device, a film projector, a digital video projector, or a computer display for displaying one or more video images on the movie screen  102 . Alternatively, or in addition to the movie screen  102 , a television (“TV”) or other video display device may also be used such as, for example, a flat screen TV, a plasma TV, an LCD TV, or other display device for displaying images for viewing by a user of the 3D glasses that may, for example, include the signal transmitter  110 , or an additional signal transmitter for signaling to the 3D glasses  104 , that may be positioned proximate and/or within the display surface of the display device. 
     In an exemplary embodiment, during operation of the system  100 , the CPU  114  controls the operation of the shutters,  106  and  108 , of the 3D glasses  104  as a function of the signals received by the signal sensor  112  from the signal transmitter  110  and/or as a function of signals received by the CPU from the battery sensor  122 . In an exemplary embodiment, the CPU  114  may direct the left shutter controller  116  to open the left shutter  106  and/or direct the right shutter controller  118  to open the right shutter  108 . 
     In an exemplary embodiment, the shutter controllers,  116  and  118 , control the operation of the shutters,  106  and  108 , respectively, by applying a voltage across the liquid crystal cells of the shutter. In an exemplary embodiment, the voltage applied across the liquid crystal cells of the shutters,  106  and  108 , alternates between negative and positive. In an exemplary embodiment, the liquid crystal cells of the shutters,  106  and  108 , open and close the same way regardless of whether the applied voltage is positive or negative. Alternating the applied voltage prevents the material of the liquid crystal cells of the shutters,  106  and  108 , from plating out on the surfaces of the cells. 
     In an exemplary embodiment, during operation of the system  100 , as illustrated in  FIGS. 2 and 3 , the system may implement a left-right shutter method  200  in which, if in  202   a , the left shutter  106  will be closed and the right shutter  108  will be opened, then in  202   b , a high voltage  202   ba  is applied to the left shutter  106  and no voltage  202   bb  followed by a small catch voltage  202   bc  are applied to the right shutter  108  by the shutter controllers,  116  and  118 , respectively. In an exemplary embodiment, applying the high voltage  202   ba  to the left shutter  106  closes the left shutter, and applying no voltage to the right shutter  108  starts opening the right shutter. In an exemplary embodiment, the subsequent application of the small catch voltage  202   bc  to the right shutter  108  prevents the liquid crystals in the right shutter from rotating too far during the opening of the right shutter  108 . As a result, in  202   b , the left shutter  106  is closed and the right shutter  108  is opened. 
     If in  202   c , the left shutter  106  will be opened and the right shutter  108  will be closed, then in  202   d , a high voltage  202   da  is applied to the right shutter  108  and no voltage  202   db  followed by a small catch voltage  202   dc  are applied to the left shutter  106  by the shutter controllers,  118  and  116 , respectively. In an exemplary embodiment, applying the high voltage  202   da  to the right shutter  108  closes the right shutter, and applying no voltage to the left shutter  106  starts opening the left shutter. In an exemplary embodiment, the subsequent application of the small catch voltage  202   dc  to the left shutter  106  prevents the liquid crystals in the left shutter from rotating too far during the opening of the left shutter  106 . As a result, in  202   d , the left shutter  106  is opened and the right shutter  108  is closed. 
     In an exemplary embodiment, the magnitude of the catch voltage used in  202   b  and  202   d  ranges from about 10 to 20% of the magnitude of the high voltage used in  202   b  and  202   d.    
     In an exemplary embodiment, during the operation of the system  100 , during the method  200 , during the time that the left shutter  106  is closed and the right shutter  108  is open in  202   b , a video image is presented for the right eye, and during the time that the left shutter  106  is opened and the right shutter  108  is closed in  202   d , a video image is presented for the left eye. In an exemplary embodiment, the video image may be displayed on one or more of the movie theater screen  102 , an LCD television screen, a digital light processing (“DLP”) television, a DLP projector, a plasma screen, and the like. 
     In an exemplary embodiment, during the operation of the system  100 , the CPU  114  will direct each shutter,  106  and  108 , to open at the same time the image intended for that shutter, and viewer eye, is presented. In an exemplary embodiment, a synchronization signal may be used to cause the shutters,  106  and  108 , to open at the correct time. 
     In an exemplary embodiment, a synchronization signal is transmitted by the signal transmitter  110  and the synchronization signal could, for example, include an infrared light. In an exemplary embodiment, the signal transmitter  110  transmits the synchronization signal toward a reflective surface and the surface reflects the signal to the signal sensor  112  positioned and mounted within the frame of the 3D glasses  104 . The reflective surface could, for example, be the movie theater screen  102  or another reflective device located on or near the movie screen such that the user of the 3D glasses  104  is generally facing the reflector while watching the movie. In an exemplary embodiment, the signal transmitter  110  may send the synchronization signal directly to the sensor  112 . In an exemplary embodiment, the signal sensor  112  may include a photo diode mounted and supported on the frame of the 3D glasses  104 . 
     The synchronization signal may provide a pulse at the beginning of each left-right lens shutter sequence  200 . The synchronization signal could be more frequent, for example providing a pulse to direct the opening of each shutter,  106  or  108 . The synchronization signal could be less frequent, for example providing a pulse once per shutter sequence  200 , once per five shutter sequences, or once per 100 shutter sequences. The CPU  114  may have an internal timer to maintain proper shutter sequencing in the absence of a synchronization signal. 
     In an exemplary embodiment, the combination of viscous liquid crystal material and narrow cell gap in the shutters,  106  and  108 , may result in a cell that is optically too thick. The liquid crystal in the shutters,  106  and  108 , blocks light transmission when voltage is applied. Upon removing the applied voltage, the molecules in the liquid crystals in the shutters,  106  and  108 , rotate back to the orientation of the alignment layer. The alignment layer orients the molecules in the liquid crystal cells to allow light transmission. In a liquid crystal cell that is optically too thick, the liquid crystal molecules rotate rapidly upon removal of power and thus rapidly increase light transmission but then the molecules rotate too far and light transmission decreases. The time from when the rotation of the liquid crystal cell molecules starts until the light transmission stabilizes, i.e. liquid crystal molecules rotation stops, is the true switching time. 
     In an exemplary embodiment, when the shutter controllers,  116  and  118 , apply the small catch voltage to the shutters,  106  and  108 , this catch voltage stops the rotation of the liquid crystal cells in the shutters before they rotate too far. By stopping the rotation of the molecules in the liquid crystal cells in the shutters,  106  and  108 , before they rotate too far, the light transmission through the molecules in the liquid crystal cells in the shutters is held at or near its peak value. Thus, the effective switching time is from when the liquid crystal cells in the shutters,  106  and  108 , start their rotation until the rotation of the molecules in the liquid crystal cells is stopped at or near the point of peak light transmission. 
     Referring now to  FIG. 4 , the transmission refers to the amount of light transmitted through a shutter,  106  or  108 , wherein a transmission value of 1 refers to the point of maximum, or a point near the maximum, light transmission through the liquid crystal cell of the shutter,  106  or  108 . Thus, for a shutter,  106  or  108 , to be able to transmit its maximum of 37% of light, a transmission level of 1 indicates that the shutter,  106  or  108 , is transmitting its maximum, i.e., 37%, of available light. Of course, depending upon the particular liquid crystal cell used, the maximum amount of light transmitted by a shutter,  106  or  108 , could be any amount, including, for example, 33%, 30%, or significantly more or less. 
     As illustrated in  FIG. 4 , in an exemplary experimental embodiment, a shutter,  106  or  108 , was operated and the light transmission  400  was measured during operation of the method  200 . In the exemplary experimental embodiment of the shutter,  106  or  108 , the shutter closed in approximately 0.5 milliseconds, then remained closed through the first half of the shutter cycle for about 7 milliseconds, then the shutter was opened to about 90% of the maximum light transmission in about one millisecond, and then the shutter remained open for about 7 milliseconds and then was closed. As a comparison, a commercially available shutter was also operated during the operation of the method  200  and exhibited the light transmission  402 . The light transmission of the shutter,  106  and  108 , of the present exemplary embodiments, during the operation of the method  200 , reached about 25-30 percent transmissive, i.e., about 90% of the maximum light transmission, as shown in  FIG. 4 , in about one millisecond whereas the other shutter only reached about 25-30 percent transmissive, i.e., about 90% of the maximum light transmission, as shown in  FIG. 4 , after about 2.5 milliseconds. Thus, the shutters,  106  and  108 , of the present exemplary embodiments, provided a significantly more responsive operation than commercially available shutters. This was an unexpected result. 
     Referring now to  FIG. 5 , in an exemplary embodiment, the system  100  implements a method  500  of operation in which, in  502 , the signal sensor  114  receives an infrared synchronization (“sync”) pulse from the signal transmitter  110 . If the 3D glasses  104  are not in the RUN MODE in  504 , then the CPU  114  determines if the 3D glasses  104  are in the OFF MODE in  506 . If the CPU  114  determines that the 3D glasses  104  are not in the OFF MODE in  506 , then the CPU  114  continues normal processing in  508  and then returns to  502 . If the CPU  114  determines that the 3D glasses  104  are in the OFF MODE in  506 , then the CPU  114  clears the sync inverter (“SI”) and validation flags in  510  to prepare the CPU  114  for the next encrypted signals, initiates a warm up sequence for the shutters,  106  and  108 , in  512 , and then proceeds with normal operations  508  and returns to  502 . 
     If the 3D glasses  104  are in the RUN MODE in  504 , then the CPU  114  determines whether the 3D glasses  104  are already configured for encryption in  514 . If the 3D glasses  104  are already configured for encryption in  514 , then the CPU  114  continues normal operations in  508  and proceeds to  502 . If the 3D glasses  104  are not already configured for encryption in  514 , then the CPU  114  checks to determine if the incoming signal is a three pulse sync signal in  516 . If the incoming signal is not a three pulse sync signal in  516 , then the CPU  114  continues normal operations in  508  and proceeds to  502 . If the incoming signal is a three pulse sync signal in  516 , then the CPU  114  receives configuration data from the signal transmitter  110  in  518  using the signal sensor  112 . The CPU  114  then decrypts the received configuration data to determine if it is valid in  520 . If the received configuration data is valid in  520 , then the CPU  114  checks to see if the new configuration ID (“CONID”) matches the previous CONID in  522 . In an exemplary embodiment, the previous CONID may be stored in a memory device such as, for example, a nonvolatile memory device, operably coupled to the CPU  114  during the manufacture or field programming of the 3D glasses  104 . If the new CONID does not match the previous CONID in  522 , then the CPU  114  directs the shutters,  106  and  108 , of the 3D glasses  104  to go into CLEAR MODE in  524 . If the new CONID does match the previous CONID, in  522 , then the CPU  114  sets the SI and CONID flags to trigger the NORMAL MODE shutter sequence for viewing three dimensional images in  526 . 
     In an exemplary embodiment, in the RUN or NORMAL MODE, the 3D glasses  104  are fully operational. In an exemplary embodiment, in the OFF MODE, the 3D glasses are not operational. In an exemplary embodiment, in the NORMAL MODE, the 3D glasses are operational and may implement the method  200 . 
     In an exemplary embodiment, the signal transmitter  110  may be located near the theater projector  130 . In an exemplary embodiment, the signal transmitter  110 , among other functions, sends a synchronization signal (“sync signal”) to the signal sensor  112  of the 3D glasses  104 . The signal transmitter  110  may instead, or in addition to, receive a synchronization signal from the theater projector  130  and/or any display and/or any emitter device. In an exemplary embodiment, an encryption signal may be used to prevent the 3D glasses  104  from operating with a signal transmitter  110  that does not contain the correct encryption signal. Furthermore, in an exemplary embodiment, the encrypted transmitter signal will not properly actuate 3D glasses  104  that are not equipped to receive and process the encrypted signal. In an exemplary embodiment, the signal transmitter  110  may also send encryption data to the 3D glasses  104 . 
     Referring now to  FIG. 6 , in an exemplary embodiment, during operation, the system  100  implements a method  600  of operation in which, in  602 , the system determines if the signal transmitter  110  was reset because the power just came on in  602 . If the signal transmitter  110  was reset because the power just came on in  602 , then the signal transmitter generates a new random sync invert flag in  604 . If the signal transmitter  110  did not have a power on reset condition in  602 , then the CPU  110   a  of the signal transmitter  110  determines whether the same sync encoding has been used for more than a predetermined amount of time in  606 . In an exemplary embodiment, the predetermined time in  606  could be four hours or the length of a typical movie or any other suitable time. If the same sync encoding has been used for more than four hours in  606 , then the CPU  110   a  of the signal transmitter  110  generates a new sync invert flag in  604 . 
     The CPU  110   a  of the signal transmitter  110  then determines if the signal transmitter is still receiving a signal from the projector  130  in  608 . If the signal transmitter  110  is not still receiving a signal from the projector  130  in  608 , then the signal transmitter  110  may use its own internal sync generator to continue sending sync signals to the signal sensor  112  at the proper time in  610 . 
     During operation, the signal transmitter  110  may, for example, alternate between two-pulse sync signals and three-pulse sync signals. In an exemplary embodiment, a two-pulse sync signal directs the 3D glasses  104  to open the left shutter  108 , and a three-pulse sync signal directs the 3D glasses  104  to open the right shutter  106 . In an exemplary embodiment, the signal transmitter  110  may send an encryption signal after every n th  signal. 
     If the signal transmitter  110  determines that it should send a three-pulse sync signal in  612 , then the signal transmitter determines the signal count since the last encryption cycle in  614 . In an exemplary embodiment, the signal transmitter  110  sends an encryption signal only once out of every ten signals. However, in an exemplary embodiment, there could be more or less signal cycles between encryption signals. If the CPU  110   a  of the signal transmitter  110  determines this is not the n th  three-pulse sync in  614 , then the CPU directs the signal transmitter to send a standard three pulse sync signal in  616 . If the sync signal is the n th  three-pulse signal, then the CPU  110   a  of the signal transmitter  110  encrypts the data in  618  and sends a three pulse sync signal with embedded configuration data in  620 . If the signal transmitter  110  determines that it should not send a three-pulse sync signal in  612 , then the signal transmitter sends a two-pulse sync signal in  622 . 
     Referring now to  FIGS. 7 and 8 , in an exemplary embodiment, during operation of the system  100 , the signal transmitter  110  implements a method  700  of operation in which the sync pulses are combined with encoded configuration data and then transmitted by the signal transmitter  110 . In particular, the signal transmitter  110  includes a firmware internal clock that generates a clock signal  800 . In  702 , the CPU  110   a  of the signal transmitter  110  determines if the clock signal  800  is at the beginning of the clock cycle  802 . If the CPU  110   a  of the signal transmitter  110  determines that the clock signal  800  is at the beginning of the clock cycle in  702 , then the CPU of the signal transmitter checks to see if a configuration data signal  804  is high or low in  704 . If the configuration data signal  804  is high, then a data pulse signal  806  is set to a high value in  706 . If the configuration data signal  804  is low, then the data pulse signal  806  is set to a low value in  708 . In an exemplary embodiment, the data pulse signal  806  may already include the sync signal. Thus, the data pulse signal  806  is combined with the synch signal in  710  and transmitted by the signal transmitter  110  in  710 . 
     In an exemplary embodiment, the encrypted form of the configuration data signal  804  may be sent during every sync signal sequence, after a predetermined number of sync signal sequences, embedded with the sync signal sequences, overlayed with the sync signal sequences, or combined with the sync signal sequences—before or after the encryption operation. Furthermore, the encrypted form of the configuration data signal  804  could be sent on either the two or three pulse sync signal, or both, or signals of any other number of pulses. In addition, the encrypted configuration data could be transmitted between the transmission of the sync signal sequence with or without encrypting the sync signals on either end of the transmission. 
     In an exemplary embodiment, encoding the configuration data signal  804 , with or without the sync signal sequence, may be provided, for example, using Manchester encoding. 
     Referring now to  FIGS. 2 ,  5 ,  8 ,  9  and  10 , in an exemplary embodiment, during the operation of the system  100 , the 3D glasses  104  implement a method  900  of operation in which, in  902 , the CPU  114  of the 3D glasses  104  checks for a wake up mode time out. In an exemplary embodiment, the presence of a wake up mode time out in  902  is provided by a clock signal  902   a  having a high pulse  902   aa  with a duration of 100 milliseconds that may occur every 2 seconds, or other predetermined time period. In an exemplary embodiment, the presence of the high pulse  902   aa  indicates a wake up mode time out. 
     If the CPU  114  detects a wake up time out in  902 , then the CPU checks for the presence or absence of a sync signal using the signal sensor  112  in  904 . If the CPU  114  detects a sync signal in  904 , then the CPU places the 3D glasses  104  in a CLEAR MODE of operation in  906 . In an exemplary embodiment, in the CLEAR MODE of operation, the 3D glasses implement, at least portions of, one or more of the methods  200  and  500 , receiving sync pulses, and/or processing configuration data  804 . In an exemplary embodiment, in the CLEAR mode of operation, the 3D glasses may provide at least the operations of the method  1300 , described below. 
     If the CPU  114  does not detect a sync signal in  904 , then the CPU places the 3D glasses  104  in an OFF MODE of operation in  908  and then, in  902 , the CPU checks for a wake up mode time out. In an exemplary embodiment, in the OFF MODE of operation, the 3D glasses do not provide the features of NORMAL or CLEAR mode of operations. 
     In an exemplary embodiment, the method  900  is implemented by the 3D glasses  104  when the 3D glasses are in either the OFF MODE or the CLEAR MODE. 
     Referring now to  FIGS. 11 and 12 , in an exemplary embodiment, during operation of the system  100 , the 3D glasses  104  implement a warm up method  1100  of operation in which, in  1102 , the CPU  114  of the 3D glasses checks for a power on of the 3D glasses. In an exemplary embodiment, the 3D glasses  104  may be powered on either by a user activating a power on switch or by an automatic wakeup sequence. In the event of a power on of the 3D glasses  104 , the shutters,  106  and  108 , of the 3D glasses may, for example, require a warm-up sequence. The molecules of the liquid crystal cells of the shutters,  106  and  108 , that do not have power for a period of time may be in an indefinite state. 
     If the CPU  114  of the 3D glasses  104  detect a power on of the 3D glasses in  1102 , then the CPU applies alternating voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , respectively, in  1104 . In an exemplary embodiment, the voltage applied to the shutters,  106  and  108 , is alternated between positive and negative peak values to avoid ionization problems in the liquid crystal cells of the shutter. In an exemplary embodiment, the voltage signals,  1104   a  and  1104   b , are at least partly out of phase with one another. Alternatively, the voltage signals,  1104   a  and  1104   b , may be in phase or completely out of phase. In an exemplary embodiment, one or both of the voltage signals,  1104   a  and  1104   b , may be alternated between a zero voltage and a peak voltage. In an exemplary embodiment, other forms of voltage signals may be applied to the shutters,  106  and  108 , such that the liquid crystal cells of the shutters are placed in a definite operational state. In an exemplary embodiment, the application of the voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , causes the shutters to open and close, either at the same time or at different times. Alternatively, the application of the voltage signals,  1104   a  and  1104   b , causes the shutters,  106  and  108 , to be closed all of the time. 
     During the application of the voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , the CPU  114  checks for a warm up time out in  1106 . If the CPU  114  detects a warm up time out in  1106 , then the CPU will stop the application of the voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , in  1108 . 
     In an exemplary embodiment, in  1104  and  1106 , the CPU  114  applies the voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , for a period of time sufficient to actuate the liquid crystal cells of the shutters. In an exemplary embodiment, the CPU  114  applies the voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , for a time out period of two seconds. In an exemplary embodiment, the maximum magnitude of the voltage signals,  1104   a  and  1104   b , may be 14 volts. In an exemplary embodiment, the time out period in  1106  may be two seconds. In an exemplary embodiment, the maximum magnitude of the voltage signals,  1104   a  and  1104   b , may be greater or lesser than 14 volts, and the time out period may be longer or shorter. In an exemplary embodiment, during the method  1100 , the CPU  114  may open and close the shutters,  106  and  108 , at a different rate than would be used for viewing a movie. In an exemplary embodiment, in  1104 , the voltage signals,  1104   a  and  1104   b , applied to the shutters,  106  and  108 , alternate at a different rate than would be used for viewing a movie. In an exemplary embodiment, in  1104 , the voltage signals applied to the shutters,  106  and  108 , do not alternate and are applied constantly during the warm up time period and therefore the liquid crystal cells of the shutters may remain opaque for the entire warm up period. In an exemplary embodiment, the warm-up method  1100  may occur with or without the presence of a synchronization signal. Thus, the method  1100  provides a WARM UP mode of the operation for the 3D glasses  104 . In an exemplary embodiment, after implementing the warm up method  1100 , the 3D glasses are placed in a NORMAL RUN MODE of operation and may then implement the method  200 . Alternatively, in an exemplary embodiment, after implementing the warm up method  1100 , the 3D glasses are placed in a CLEAR MODE of operation and may then implement the method  1300 , described below. 
     Referring now to  FIGS. 13 and 14 , in an exemplary embodiment, during the operation of the system  100 , the 3D glasses  104  implement a method  1300  of operation in which, in  1302 , the CPU  114  checks to see if the sync signal detected by the signal sensor  112  is valid or invalid. If the CPU  114  determines that the sync signal is invalid in  1302 , then the CPU applies voltage signals,  1304   a  and  1304   b , to the shutters,  106  and  108 , of the 3D glasses  104  in  1304 . In an exemplary embodiment, the voltage applied to the shutters,  106  and  108 , is alternated between positive and negative peak values to avoid ionization problems in the liquid crystal cells of the shutter. In an exemplary embodiment, one or both of the voltage signals,  1104   a  and  1104   b , may be alternated between a zero voltage and a peak voltage. In an exemplary embodiment, other forms of voltage signals may be applied to the shutters,  106  and  108 , such that the liquid crystal cells of the shutters remain open so that the user of the 3D glasses  104  can see normally through the shutters. In an exemplary embodiment, the application of the voltage signals,  1104   a  and  1104   b , to the shutters,  106  and  108 , causes the shutters to open. 
     During the application of the voltage signals,  1304   a  and  1304   b , to the shutters,  106  and  108 , the CPU  114  checks for a clearing time out in  1306 . If the CPU  114  detects a clearing time out in  1306 , then the CPU will stop the application of the voltage signals,  1304   a  and  1304   b , to the shutters,  106  and  108 , in  1308 . 
     Thus, in an exemplary embodiment, if the 3D glasses  104  do not detect a valid synchronization signal, they may go to a clear mode of operation and implement the method  1300 . In the clear mode of operation, in an exemplary embodiment, both shutters,  106  and  108 , of the 3D glasses  104  remain open so that the viewer can see normally through the shutters of the 3D glasses. In an exemplary embodiment, a constant voltage is applied, alternating positive and negative, to maintain the liquid crystal cells of the shutters,  106  and  108 , of the 3D glasses in a clear state. The constant voltage could, for example, be in the range of 2-3 volts, but the constant voltage could be any other voltage suitable to maintain reasonably clear shutters. In an exemplary embodiment, the shutters,  106  and  108 , of the 3D glasses  104  may remain clear until the 3D glasses are able to validate an encryption signal. In an exemplary embodiment, the shutters,  106  and  108 , of the 3D glasses may alternately open and close at a rate that allows the user of the 3D glasses to see normally. 
     Thus, the method  1300  provides a method of clearing the operation of the 3D glasses  104  and thereby provide a CLEAR MODE of operation. 
     Referring now to  FIG. 15 , in an exemplary embodiment, during the operation of the system  100 , the 3D glasses  104  implement a method  1500  of monitoring the battery  120  in which, in  1502 , the CPU  114  of the 3D glasses uses the battery sensor  122  to determine the remaining useful life of the battery. If the CPU  114  of the 3D glasses determines that the remaining useful life of the battery  120  is not adequate in  1502 , then the CPU provides an indication of a low battery life condition in  1504 . 
     In an exemplary embodiment, an inadequate remaining battery life may, for example, be any period less than 3 hours. In an exemplary embodiment, an adequate remaining battery life may be preset by the manufacturer of the 3D glasses and/or programmed by the user of the 3D glasses. 
     In an exemplary embodiment, in  1504 , the CPU  114  of the 3D glasses  104  will indicate a low battery life condition by causing the shutters,  106  and  108 , of the 3D glasses to blink slowly, by causing the shutters to simultaneously blink at a moderate rate that is visible to the user of the 3D glasses, by flashing an indicator light, by generating an audible sound, and the like. 
     In an exemplary embodiment, if the CPU  114  of the 3D glasses  104  detects that the remaining battery life is insufficient to last for a specified period of time, then the CPU of the 3D glasses will indicate a low battery condition in  1504  and then prevent the user from turning on the 3D glasses. 
     In an exemplary embodiment, the CPU  114  of the 3D glasses  104  determines whether or not the remaining battery life is adequate every time the 3D glasses transition to the CLEAR MODE of operation. 
     In an exemplary embodiment, if the CPU  114  of the 3D glasses determines that the battery will last for at least the predetermined adequate amount of time, then the 3D glasses will continue to operate normally. Operating normally may include staying in the CLEAR MODE of operation for five minutes while checking for a valid signal from the signal transmitter  110  and then going to an OFF MODE wherein the 3D glasses  104  periodically wake up to check for a signal from the signal transmitter. 
     In an exemplary embodiment, the CPU  114  of the 3D glasses  104  checks for a low battery condition just before shutting off the 3D glasses. In an exemplary embodiment, if the battery  120  will not last for the predetermined adequate remaining life time, then the shutters,  106  and  108 , will begin blinking slowly. 
     In an exemplary embodiment, if the battery  120  will not last for the predetermined adequate remaining life time, the shutters,  106  and/or  108 , are placed into an opaque condition, i.e., the liquid crystal cells are closed, for two seconds and then placed into a clear condition, i.e., the liquid crystal cells are opened, for 1/10 th  of a second. The time period that the shutters,  106  and/or  108 , are closed and opened may be any time period. 
     In an exemplary embodiment, the 3D glasses  104  may check for a low battery condition at any time including during warm up, during normal operation, during clear mode, during power off mode, or at the transition between any conditions. In an exemplary embodiment, if a low battery life condition is detected at a time when the viewer is likely to be in the middle of a movie, the 3D glasses  104  may not immediately indicate the low battery condition. 
     In some embodiments, if the CPU  114  of the 3D glasses  104  detects a low battery level, the user will not be able to power the 3D glasses on. 
     Referring now to  FIG. 16 , in an exemplary embodiment, a tester  1600  may be positioned proximate the 3D glasses  104  in order to verify that the 3D glasses are working properly. In an exemplary embodiment, the tester  1600  includes a signal transmitter  1600   a  for transmitting test signals  1600   b  to the signal sensor  112  of the 3D glasses. In an exemplary embodiment, the test signal  1600   b  may include a sync signal having a low frequency rate to cause the shutters,  106  and  108 , of the 3D glasses  104  to blink at a low rate that is visible to the user of the 3D glasses. In an exemplary embodiment, a failure of the shutters,  106  and  108 , to blink in response to the test signal  1600   b  may indicate a failure on the part of the 3D glasses  104  to properly operate. 
     Referring now to  FIG. 17 , in an exemplary embodiment, the 3D glasses  104  further include a charge pump  1700  operably coupled to the CPU  114 , the shutter controllers,  116  and  118 , the battery  120  for converting the output voltage of the battery to a higher output voltage for use in operating the shutter controllers. 
     Referring to  FIGS. 18 ,  18   a ,  18   b ,  18   c  and  18   d , an exemplary embodiment of 3D glasses  1800  is provided that is substantially identical in design and operation as the 3D glasses  104  illustrated and described above except as noted below. The 3D glasses  1800  include a left shutter  1802 , a right shutter  1804 , a left shutter controller  1806 , a right shutter controller  1808 , a CPU  1810 , a battery sensor  1812 , a signal sensor  1814  and a charge pump  1816 . In an exemplary embodiment, the design and operation of the left shutter  1802 , the right shutter  1804 , the left shutter controller  1806 , the right shutter controller  1808 , the CPU  1810 , the battery sensor  1812 , the signal sensor  1814 , and the charge pump  1816  of the 3D glasses  1800  are substantially identical to the left shutter  106 , the right shutter  108 , the left shutter controller  116 , the right shutter controller  118 , the CPU  114 , the battery sensor  122 , the signal sensor  112 , and the charge pump  1700  of the 3D glasses  104  described and illustrated above. 
     In an exemplary embodiment, the 3D glasses  1800  include the following components: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 NAME 
                 VALUE/ID 
               
               
                   
                   
               
             
            
               
                   
                 R12 
                 10K 
               
               
                   
                 R9 
                 100K 
               
               
                   
                 D3 
                 BAS7004 
               
               
                   
                 R6 
                 4.7K 
               
               
                   
                 D2 
                 BP104FS 
               
               
                   
                 R1 
                 10M 
               
               
                   
                 C5 
                 .1 uF 
               
               
                   
                 R5 
                 20K 
               
               
                   
                 U5-2 
                 MCP6242 
               
               
                   
                 R3 
                 10K 
               
               
                   
                 C6 
                 .1 uF 
               
               
                   
                 C7 
                 .001 uF 
               
               
                   
                 C10 
                 .33 uF 
               
               
                   
                 R7 
                 1M 
               
               
                   
                 D1 
                 BAS7004 
               
               
                   
                 R2 
                 330K 
               
               
                   
                 U5-1 
                 MCP6242 
               
               
                   
                 R4 
                 1M 
               
               
                   
                 R11 
                 330K 
               
               
                   
                 U6 
                 MCP111 
               
               
                   
                 R13 
                 100K 
               
               
                   
                 U3 
                 PIC16F636 
               
               
                   
                 C1 
                 47 uF 
               
               
                   
                 C2 
                 .1 uF 
               
               
                   
                 R8 
                 10K 
               
               
                   
                 R10 
                 20K 
               
               
                   
                 R14 
                 10K 
               
               
                   
                 R15 
                 100K 
               
               
                   
                 Q1 
                 NDS0610 
               
               
                   
                 D6 
                 MAZ31200 
               
               
                   
                 D5 
                 BAS7004 
               
               
                   
                 L1 
                 1 mh 
               
               
                   
                 C11 
                 1 uF 
               
               
                   
                 C3 
                 .1 uF 
               
               
                   
                 U1 
                 4052 
               
               
                   
                 R511 
                 470 
               
               
                   
                 C8 
                 .1 uF 
               
               
                   
                 C4 
                 .1 uF 
               
               
                   
                 U2 
                 4052 
               
               
                   
                 R512 
                 470 
               
               
                   
                 C1 
                 47 uF 
               
               
                   
                 C11 
                 1 uF 
               
               
                   
                 Left Lens 
                 LCD 1 
               
               
                   
                 Right Lens 
                 LCD 2 
               
               
                   
                 BT1 
                 3 V Li 
               
               
                   
                   
               
            
           
         
       
     
     In an exemplary embodiment, the left shutter controller  1806  includes a digitally controlled analog switch U 1  that, under the control of the CPU  1810 , depending upon the mode of operation, applies a voltage across the left shutter  1802  for controlling the operation of the left shutter. In similar fashion, the right shutter controller  1808  includes a digitally controller analog switch U 2  that, under the control of the CPU  1810 , depending upon the mode of operation, applies a voltage across the right shutter  1804  for controlling the operation of the right shutter. In an exemplary embodiment, U 1  and U 2  are conventional commercially available digitally controlled analog switches available from Unisonic Technologies or Texas Instruments as part numbers, UTC 4052 and TI 4052, respectively. 
     As will be recognized by persons having ordinary skill in the art, the 4052 digitally controlled analog switch includes control input signals A, B and INHIBIT (“INH”), switch I/O signals X 0 , X 1 , X 2 , X 3 , Y 0 , Y 1 , Y 2  and Y 3 , and output signals X and Y and further provides the following truth table: 
                            TRUTH TABLE                     Control Inputs                                 Select                                     Inhibit   B   A   ON Switches                                         0   0   0   Y0   X0       0   0   1   Y1   X1       0   1   0   Y2   X2       0   1   1   Y3   X3                                 1   X   X   None               * X = Don&#39;t Care            
And, as illustrated in  FIG. 19 , the 4052 digitally controlled analog switch also provides a functional diagram  1900 . Thus, the 4052 digitally controlled analog switch provides a digitally controlled analog switch, each having two independent switches, that permits the left and right shutter controllers,  1806  and  1808 , to selectively apply a controlled voltage across the left and right shutters,  1802  and  1804 , to control the operation of the shutters.
 
     In an exemplary embodiment, the CPU  1810  includes a microcontroller U 3  for generating output signals A, B, C, D and E for controlling the operation of the digitally controlled analog switches, U 1  and U 2 , of the left and right shutter controllers,  1806  and  1808 . The output control signals A, B and C of the microcontroller U 3  provide the following input control signals A and B to each of the digitally controlled analog switches, U 1  and U 2 : 
     
       
         
           
               
               
               
             
               
                   
               
               
                 U3 - Output Control 
                 U1 - Input Control 
                 U2 - Input Control 
               
               
                 Signals 
                 Signals 
                 Signals 
               
               
                   
               
             
            
               
                 A 
                 A 
                   
               
               
                 B 
                   
                 A 
               
               
                 C 
                 B 
                 B 
               
               
                   
               
            
           
         
       
     
     In an exemplary embodiment, the output control signals D and E of the microcontroller U 3  provide, or otherwise affect, the switch I/O signals X 0 , X 1 , X 2 , X 3 , Y 0 , Y 1 , Y 2  and Y 3  of the digitally controlled analog switches, U 1  and U 2 : 
     
       
         
           
               
               
               
             
               
                   
               
               
                 U3 - Output Control 
                 U1 - Switch I/O 
                 U2 - Switch I/O 
               
               
                 Signals 
                 Signals 
                 Signals 
               
               
                   
               
             
            
               
                 D 
                 X3, Y1 
                 X0, Y2 
               
               
                 E 
                 X3, Y1 
                 X0, Y2 
               
               
                   
               
            
           
         
       
     
     In an exemplary embodiment, the microcontroller U 3  of the CPU  1810  is a model number PIC16F636 programmable microcontroller, commercially available from Microchip. 
     In an exemplary embodiment, the battery sensor  1812  includes a power detector U 6  for sensing the voltage of the battery  120 . In an exemplary embodiment, the power detector U 6  is a model MCP111 micropower voltage detector, commercially available from Microchip. 
     In an exemplary embodiment, the signal sensor  1814  includes a photodiode D 2  for sensing the transmission of the signals, including the sync signal and/or configuration data, by the signal transmitter  110 . In an exemplary embodiment, the photodiode D 2  is a model BP104FS photodiode, commercially available from Osram. In an exemplary embodiment, the signal sensor  1814  further includes operational amplifiers, U 5 - 1  and U 5 - 2 , and related signal conditioning components, resistors R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 9 , R 11 , and R 12 , capacitors C 5 , C 6 , C 7 , and C 10 , and schottky diodes, D 1  and D 3 . 
     In an exemplary embodiment, the charge pump  1816  amplifies the magnitude of the output voltage of the battery  120 , using a charge pump, from 3V to −12V. In an exemplary embodiment, the charge pump  1816  includes a MOSFET Q 1 , a schottky diode D 5 , an inductor L 1 , and a zener diode D 6 . In an exemplary embodiment, the output signal of the charge pump  1816  is provided as input signals to switch I/O signals X 2  and Y 0  of the digitally controlled analog switch U 1  of the left shutter controller  1806  and as input signals to switch I/O signals X 3  and Y 1  of the digitally controlled analog switch U 2  of the right shutter controller  1808 . 
     As illustrated in  FIG. 20 , in an exemplary embodiment, during operation of the 3D glasses  1800 , the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide various voltages across one or both of the left and right shutters,  1802  and  1804 . In particular, the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide: 1) a positive or negative 15 volts across one or both of the left and right shutters,  1802  and  1804 , 2) a positive or negative voltage, in the range of 2-3 volts, across one or both of the left and right shutters, or 3) provide 0 volts, i.e., a neutral state, across one or both of the left and right shutters. In an exemplary, embodiment, the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide 15 volts by, for example, combining +3 volts with −12 volts to achieve a differential of 15 volts across the one or both of the left and right shutters,  1802  and  1804 . In an exemplary embodiment, the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide a 2 volt catch voltage, for example, by reducing the 3 volt output voltage of the battery  120  to 2 volts with a voltage divider, including components R 8  and R 10 . 
     Alternatively, the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide: 1) a positive or negative 15 volts across one or both of the left and right shutters,  1802  and  1804 , 2) a positive or negative voltage, of about 2 volts, across one or both of the left and right shutters, 3) a positive or negative voltage, of about 3 volts, across one or both of the left and right shutters, or 4) provide 0 volts, i.e., a neutral state, across one or both of the left and right shutters. In an exemplary embodiment, the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide 15 volts by, for example, combining +3 volts with −12 volts to achieve a differential of 15 volts across the one or both of the left and right shutters,  1802  and  1804 . In an exemplary embodiment, the digitally controlled analog switches, U 1  and U 2 , under the control of the control signals A, B, C, D, and E of the CPU  1810 , may provide a 2 volt catch voltage, for example, by reducing the 3 volt output voltage of the battery  120  to 2 volts with a voltage divider, including components R 8  and R 10 . 
     Referring now to  FIGS. 21 and 22 , in an exemplary embodiment, during the operation of the 3D glasses  1800 , the 3D glasses execute a normal run mode of operation  2100  in which the control signals A, B, C, D and E generated by the CPU  1810  are used to control the operation of the left and right shutter controllers,  1806  and  1808 , to in turn control the operation of the left and right shutters,  1802  and  1804 , as a function of the type of sync signal detected by the signal sensor  1814 . 
     In particular, in  2102 , if the CPU  1810  determines that the signal sensor  1814  has received a sync signal, then, in  2104 , the CPU determines the type of sync signal received. In an exemplary embodiment, a sync signal that includes 3 pulses indicates that the left shutter  1802  should be closed and the right shutter  1804  should be opened while a sync signal that includes 2 pulses indicates that the left shutter should be opened and the right shutter should be closed. More generally, any number of different pulses may used to control the opening and closing of the left and right shutters,  1802  and  1804 . 
     If, in  2104 , the CPU  1810  determines that sync signal received indicates that the left shutter  1802  should be closed and the right shutter  1804  should be opened, then the CPU transmits control signals A, B, C, D and E to the left and right shutter controllers,  1806  and  1808 , in  2106 , to apply a high voltage to the left shutter  1802  and no voltage followed by a small catch voltage to the right shutter  1804 . In an exemplary embodiment, the magnitude of the high voltage applied to the left shutter  1802  in  2106  is 15 volts. In an exemplary embodiment, the magnitude of the catch voltage applied to the right shutter  1804  in  2106  is 2 volts. In an exemplary embodiment, the catch voltage is applied to the right shutter  1804  in  2106  by controlling the operational state of the control signal D, which can be either low, high or open, to be open thereby enabling the operation of the voltage divider components R 8  and R 10 , and maintaining the control signal E at a high state. In an exemplary embodiment, the application of the catch voltage in  2106  to the right shutter  1804  is delayed by a predetermined time period to allow faster rotation of the molecules within the liquid crystals of the right shutter during the predetermined time period. The subsequent application of the catch voltage, after the expiration of the predetermined time period, then prevents the molecules within the liquid crystals in the right shutter  1804  from rotating too far during the opening of the right shutter. 
     Alternatively, if, in  2104 , the CPU  1820  determines that sync signal received indicates that the left shutter  1802  should be opened and the right shutter  1804  should be closed, then the CPU transmits control signals A, B, C, D and E to the left and right shutter controllers,  1806  and  1808 , in  2108 , to apply a high voltage to the right shutter  1804  and no voltage followed by a small catch voltage to the left shutter  1802 . In an exemplary embodiment, the magnitude of the high voltage applied to the right shutter  1804  in  2108  is 15 volts. In an exemplary embodiment, the magnitude of the catch voltage applied to the left shutter  1802  in  2108  is 2 volts. In an exemplary embodiment, the catch voltage is applied to the left shutter  1802  in  2108  by controlling the control signal D to be open thereby enabling the operation of the voltage divider components R 8  and R 10 , and maintaining the control signal E at a high level. In an exemplary embodiment, the application of the catch voltage in  2108  to the left shutter  1802  is delayed by a predetermined time period to allow faster rotation of the molecules within the liquid crystals of the left shutter during the predetermined time period. The subsequent application of the catch voltage, after the expiration of the predetermined time period, then prevents the molecules within the liquid crystals in the left shutter  1802  from rotating too far during the opening of the left shutter. 
     In an exemplary embodiment, during the method  2100 , the voltages applied to the left and right shutters,  1802  and  1804 , are alternately positive and negative in subsequent repetitions of the steps  2106  and  2108  in order to prevent damage to the liquid crystal cells of the left and right shutters. 
     Thus, the method  2100  provides a NORMAL or RUN MODE of operation for the 3D glasses  1800 . 
     Referring now to  FIGS. 23 and 24 , in an exemplary embodiment, during operation of the 3D glasses  1800 , the 3D glasses implement a warm up method  2300  of operation in which the control signals A, B, C, D and E generated by the CPU  1810  are used to control the operation of the left and right shutter controllers,  1806  and  1808 , to in turn control the operation of the left and right shutters,  1802  and  1804 . 
     In  2302 , the CPU  1810  of the 3D glasses checks for a power on of the 3D glasses. In an exemplary embodiment, the 3D glasses  1810  may be powered on either by a user activating a power on switch or by an automatic wakeup sequence. In the event of a power on of the 3D glasses  1810 , the shutters,  1802  and  1804 , of the 3D glasses may, for example, require a warm-up sequence. The liquid crystal cells of the shutters,  1802  and  1804 , that do not have power for a period of time may be in an indefinite state. 
     If the CPU  1810  of the 3D glasses  1800  detects a power on of the 3D glasses in  2302 , then the CPU applies alternating voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , respectively, in  2304 . In an exemplary embodiment, the voltage applied to the left and right shutters,  1802  and  1804 , is alternated between positive and negative peak values to avoid ionization problems in the liquid crystal cells of the shutter. In an exemplary embodiment, the voltage signals,  2304   a  and  2304   b , may be at least partially out of phase with one another. In an exemplary embodiment, one or both of the voltage signals,  2304   a  and  2304   b , may be alternated between a zero voltage and a peak voltage. In an exemplary embodiment, other forms of voltage signals may be applied to the left and right shutters,  1802  and  1804 , such that the liquid crystal cells of the shutters are placed in a definite operational state. In an exemplary embodiment, the application of the voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , causes the shutters to open and close, either at the same time or at different times. Alternatively, the application of the voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , may causes the shutters to remain closed. 
     During the application of the voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , the CPU  1810  checks for a warm up time out in  2306 . If the CPU  1810  detects a warm up time out in  2306 , then the CPU will stop the application of the voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , in  2308 . 
     In an exemplary embodiment, in  2304  and  2306 , the CPU  1810  applies the voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , for a period of time sufficient to actuate the liquid crystal cells of the shutters. In an exemplary embodiment, the CPU  1810  applies the voltage signals,  2304   a  and  2304   b , to the left and right shutters,  1802  and  1804 , for a period of two seconds. In an exemplary embodiment, the maximum magnitude of the voltage signals,  2304   a  and  2304   b , may be 15 volts. In an exemplary embodiment, the time out period in  2306  may be two seconds. In an exemplary embodiment, the maximum magnitude of the voltage signals,  2304   a  and  2304   b , may be greater or lesser than 15 volts, and the time out period may be longer or shorter. In an exemplary embodiment, during the method  2300 , the CPU  1810  may open and close the left and right shutters,  1802  and  1804 , at a different rate than would be used for viewing a movie. In an exemplary embodiment, in  2304 , the voltage signals applied to the left and right shutters,  1802  and  1804 , do not alternate and are applied constantly during the warm up time period and therefore the liquid crystal cells of the shutters may remain opaque for the entire warm up period. In an exemplary embodiment, the warm-up method  2300  may occur with or without the presence of a synchronization signal. Thus, the method  2300  provides a WARM UP mode of the operation for the 3D glasses  1800 . In an exemplary embodiment, after implementing the warm up method  2300 , the 3D glasses  1800  are placed in a NORMAL or RUN MODE of operation and may then implement the method  2100 . Alternatively, in an exemplary embodiment, after implementing the warm up method  2300 , the 3D glasses  1800  are placed in a CLEAR MODE of operation and may then implement the method  2500  described below. 
     Referring now to  FIGS. 25 and 26 , in an exemplary embodiment, during the operation of the 3D glasses  1800 , the 3D glasses implement a method  2500  of operation in which the control signals A, B, C, D and E generated by the CPU  1810  are used to control the operation of the left and right shutter controllers,  1806  and  1808 , to in turn control the operation of the left and right shutters,  1802  and  1804 , as a function of the sync signal received by the signal sensor  1814 . 
     In  2502 , the CPU  1810  checks to see if the sync signal detected by the signal sensor  1814  is valid or invalid. If the CPU  1810  determines that the sync signal is invalid in  2502 , then the CPU applies voltage signals,  2504   a  and  2504   b , to the left and right shutters,  1802  and  1804 , of the 3D glasses  1800  in  2504 . In an exemplary embodiment, the voltage applied,  2504   a  and  2504   b , to the left and right shutters,  1802  and  1804 , is alternated between positive and negative peak values to avoid ionization problems in the liquid crystal cells of the shutter. In an exemplary embodiment, one or both of the voltage signals,  2504   a  and  2504   b , may be alternated between a zero voltage and a peak voltage. In an exemplary embodiment, other forms of voltage signals may be applied to the left and right shutters,  1802  and  1804 , such that the liquid crystal cells of the shutters remain open so that the user of the 3D glasses  1800  can see normally through the shutters. In an exemplary embodiment, the application of the voltage signals,  2504   a  and  2504   b , to the left and right shutters,  1802  and  1804 , causes the shutters to open. 
     During the application of the voltage signals,  2504   a  and  2504   b , to the left and right shutters,  1802  and  1804 , the CPU  1810  checks for a clearing time out in  2506 . If the CPU  1810  detects a clearing time out in  2506 , then the CPU  1810  will stop the application of the voltage signals,  2504   a  and  2504   b , to the shutters,  1802  and  1804 , in  2508 . 
     Thus, in an exemplary embodiment, if the 3D glasses  1800  do not detect a valid synchronization signal, they may go to a clear mode of operation and implement the method  2500 . In the clear mode of operation, in an exemplary embodiment, both shutters,  1802  and  1804 , of the 3D glasses  1800  remain open so that the viewer can see normally through the shutters of the 3D glasses. In an exemplary embodiment, a constant voltage is applied, alternating positive and negative, to maintain the liquid crystal cells of the shutters,  1802  and  1804 , of the 3D glasses  1800  in a clear state. The constant voltage could, for example, be in the range of 2-3 volts, but the constant voltage could be any other voltage suitable to maintain reasonably clear shutters. In an exemplary embodiment, the shutters,  1802  and  1804 , of the 3D glasses  1800  may remain clear until the 3D glasses are able to validate an encryption signal and/or until a clearing mode time out. In an exemplary embodiment, the shutters,  1802  and  1804 , of the 3D glasses  1800  may remain clear until the 3D glasses are able to validate an encryption signal and then may implement the method  2100  and/or if a time out occurs in  2506 , then may implement the method  900 . In an exemplary embodiment, the shutters,  1802  and  1804 , of the 3D glasses  1800  may alternately open and close at a rate that allows the user of the 3D glasses to see normally. 
     Thus, the method  2500  provides a method of clearing the operation of the 3D glasses  1800  and thereby provide a CLEAR MODE of operation. 
     Referring now to  FIGS. 27 and 28 , in an exemplary embodiment, during the operation of the 3D glasses  1800 , the 3D glasses implement a method  2700  of monitoring the battery  120  in which the control signals A, B, C, D and E generated by the CPU  1810  are used to control the operation of the left and right shutter controllers,  1806  and  1808 , to in turn control the operation of the left and right shutters,  1802  and  1804 , as a function of the condition of the battery  120  as detected by battery sensor  1812 . 
     In  2702 , the CPU  1810  of the 3D glasses uses the battery sensor  1812  to determine the remaining useful life of the battery  120 . If the CPU  1810  of the 3D glasses  1800  determines that the remaining useful life of the battery  120  is not adequate in  2702 , then the CPU provides an indication of a low battery life condition in  2704 . 
     In an exemplary embodiment, an inadequate remaining battery life may, for example, be any period less than 3 hours. In an exemplary embodiment, an adequate remaining battery life may be preset by the manufacturer of the 3D glasses  1800  and/or programmed by the user of the 3D glasses. 
     In an exemplary embodiment, in  2704 , the CPU  1810  of the 3D glasses  1800  will indicate a low battery life condition by causing the left and right shutters,  1802  and  1804 , of the 3D glasses to blink slowly, by causing the shutters to simultaneously blink at a moderate rate that is visible to the user of the 3D glasses, by flashing an indicator light, by generating an audible sound, and the like. 
     In an exemplary embodiment, if the CPU  1810  of the 3D glasses  1800  detects that the remaining battery life is insufficient to last for a specified period of time, then the CPU of the 3D glasses will indicate a low battery condition in  2704  and then prevent the user from turning on the 3D glasses. 
     In an exemplary embodiment, the CPU  1810  of the 3D glasses  1800  determines whether or not the remaining battery life is adequate every time the 3D glasses transition to the OFF MODE and/or to the CLEAR MODE of operation. 
     In an exemplary embodiment, if the CPU  1810  of the 3D glasses  1800  determines that the battery will last for at least the predetermined adequate amount of time, then the 3D glasses will continue to operate normally. Operating normally may, for example, include staying in the CLEAR MODE of operation for five minutes while checking for a signal from the signal transmitter  110  and then going to the OFF MODE or to a turn-on mode wherein the 3D glasses  1800  periodically wake up to check for a signal from the signal transmitter. 
     In an exemplary embodiment, the CPU  1810  of the 3D glasses  1800  checks for a low battery condition just before shutting off the 3D glasses. In an exemplary embodiment, if the battery  120  will not last for the predetermined adequate remaining life time, then the shutters,  1802  and  1804 , will begin blinking slowly. 
     In an exemplary embodiment, if the battery  120  will not last for the predetermined adequate remaining life time, the shutters,  1802  and/or  1804 , are placed into an opaque condition, i.e., the liquid crystal cells are closed, for two seconds and then placed into a clear condition, i.e., the liquid crystal cells are opened, for 1/10 th  of a second. The time period that the shutters,  1802  and/or  1804 , are closed and opened may be any time period. In an exemplary embodiment, the blinking of the shutters,  1802  and  1804 , is synchronized with providing power to the signal sensor  1814  to permit the signal sensor to check for a signal from the signal transmitter  110 . 
     In an exemplary embodiment, the 3D glasses  1800  may check for a low battery condition at any time including during warm up, during normal operation, during clear mode, during power off mode, or at the transition between any conditions. In an exemplary embodiment, if a low battery life condition is detected at a time when the viewer is likely to be in the middle of a movie, the 3D glasses  1800  may not immediately indicate the low battery condition. 
     In some embodiments, if the CPU  1810  of the 3D glasses  1800  detects a low battery level, the user will not be able to power the 3D glasses on. 
     Referring now to  FIG. 29 , in an exemplary embodiment, during the operation of the 3D glasses  1800 , the 3D glasses implement a method for shutting down the 3D glasses in which the control signals A, B, C, D and E generated by the CPU  1810  are used to control the operation of the left and right shutter controllers,  1806  and  1808 , to in turn control the operation of the left and right shutters,  1802  and  1804 , as a function of the condition of the battery  120  as detected by the battery sensor  1812 . In particular, if the user of 3D glasses  1800  selects shutting down the 3D glasses or the CPU  1810  selects shutting down the 3D glasses, then the voltage applied to the left and right shutters,  1802  and  1804 , of the 3D glasses are both set to zero. 
     Referring to  FIGS. 30 ,  30   a ,  30   b  and  30   c , an exemplary embodiment of 3D glasses  3000  is provided that is substantially identical in design and operation as the 3D glasses  104  illustrated and described above except as noted below. The 3D glasses  3000  include a left shutter  3002 , a right shutter  3004 , a left shutter controller  3006 , a right shutter controller  3008 , common shutter controller  3010 , a CPU  3012 , a signal sensor  3014 , a charge pump  3016 , and a voltage supply  3018 . In an exemplary embodiment, the design and operation of the left shutter  3002 , the right shutter  3004 , the left shutter controller  3006 , the right shutter controller  3008 , the CPU  3012 , the signal sensor  3014 , and the charge pump  3016  of the 3D glasses  3000  are substantially identical to the left shutter  106 , the right shutter  108 , the left shutter controller  116 , the right shutter controller  118 , the CPU  114 , the signal sensor  112 , and the charge pump  1700  of the 3D glasses  104  described and illustrated above, except as described below and illustrated herein. 
     In an exemplary embodiment, the 3D glasses  3000  include the following components: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 NAME 
                 VALUE/ID 
               
               
                   
                   
               
             
            
               
                   
                 R13 
                 10K 
               
               
                   
                 D5 
                 BAS7004 
               
               
                   
                 R12 
                 100K 
               
               
                   
                 D3 
                 BP104F 
               
               
                   
                 R10 
                 2.2M 
               
               
                   
                 U5-1 
                 MIC863 
               
               
                   
                 R3 
                 10K 
               
               
                   
                 R7 
                 10K 
               
               
                   
                 R8 
                 10K 
               
               
                   
                 R5 
                 1M 
               
               
                   
                 C7 
                 .001 uF 
               
               
                   
                 R9 
                 47K 
               
               
                   
                 R11 
                 1M 
               
               
                   
                 C1 
                 .1 uF 
               
               
                   
                 C9 
                 .1 uF 
               
               
                   
                 D1 
                 BAS7004 
               
               
                   
                 R2 
                 330K 
               
               
                   
                 U5-2 
                 MIC863 
               
               
                   
                 U3 
                 MIC7211 
               
               
                   
                 U2 
                 PIC16F636 
               
               
                   
                 C3 
                 .1 uF 
               
               
                   
                 C12 
                 47 uF 
               
               
                   
                 C2 
                 .1 uF 
               
               
                   
                 LCD1 
                 LEFT SHUTTER 
               
               
                   
                 C14 
                 .1 uF 
               
               
                   
                 LCD2 
                 RIGHT SHUTTER 
               
               
                   
                 U1 
                 4053 
               
               
                   
                 U6 
                 4053 
               
               
                   
                 C4 
                 .1 uF 
               
               
                   
                 U4 
                 4053 
               
               
                   
                 R14 
                 10K 
               
               
                   
                 R15 
                 100K 
               
               
                   
                 Q1 
                 NDS0610 
               
               
                   
                 L1 
                 1 mh 
               
               
                   
                 D6 
                 BAS7004 
               
               
                   
                 D7 
                 MAZ31200 
               
               
                   
                 C13 
                 1 uF 
               
               
                   
                 C5 
                 1 uF 
               
               
                   
                 Q2 
               
               
                   
                 R16 
                 1M 
               
               
                   
                 R1 
                 1M 
               
               
                   
                 BT1 
                 3 V Li 
               
               
                   
                   
               
            
           
         
       
     
     In an exemplary embodiment, the left shutter controller  3006  includes a digitally controlled analog switch U 1  that, under the control of the common controller  3010 , that includes a digitally controlled analog switch U 4 , and the CPU  3012 , depending upon the mode of operation, applies a voltage across the left shutter  3002  for controlling the operation of the left shutter. In similar fashion, the right shutter controller  3008  includes a digitally controller analog switch U 6  that, under the control of the common controller  3010  and the CPU  3012 , depending upon the mode of operation, applies a voltage across the right shutter  3004  for controlling the operation of the right shutter  3004 . In an exemplary embodiment, U 1 , U 4  and U 6  are conventional commercially available digitally controlled analog switches available from Unisonic Technologies as part number UTC 4053. 
     As will be recognized by persons having ordinary skill in the art, the UTC 4053 digitally controlled analog switch includes control input signals A, B, C and INHIBIT (“INH”), switch I/O signals X 0 , X 1 , Y 0 , Y 1 , Z 0  and Z 1 , and output signals X, Y and Z, and further provides the following truth table: 
                            TRUTH TABLE                     Control inputs                                 Select   ON Switches       Inhibit   C B A   UTC 4053               0   0 0 0   Z0 Y0 X0       0   0 0 1   Z0 Y0 X1       0   0 1 0   Z0 Y1 X0       0   0 1 1   Z0 Y1 X1       0   1 0 0   Z1 Y0 X0       0   1 0 1   Z1 Y0 X1       0   1 1 0   Z1 Y1 X0       0   1 1 1   Z1 Y1 X1       1   x x x   None               x = Don&#39;t Care            
And, as illustrated in  FIG. 31 , the UTC 4053 digitally controlled analog switch also provides a functional diagram  3100 . Thus, the UTC 4053 provides a digitally controlled analog switch, each having three independent switches, that permits the left and right shutter controllers,  3006  and  3008 , and the common shutter controller  3010 , under the control of the CPU  3012 , to selectively apply a controlled voltage across the left and right shutters,  3002  and  3004 , to control the operation of the shutters.
 
     In an exemplary embodiment, the CPU  3012  includes a microcontroller U 2  for generating output signals A, B, C, D, E, F and G for controlling the operation of the digitally controlled analog switches, U 1 , U 6  and U 4 , of the left and right shutter controllers,  3006  and  3008 , and the common shutter controller  3010 . 
     The output control signals A, B, C, D, E, F and G of the microcontroller U 2  provide the following input control signals A, B, C and INH to each of the digitally controlled analog switches, U 1 , U 6  and U 4 : 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                 U2 - Output 
                   
                   
                   
               
               
                 Control 
                 U1 - Input 
                 U6 - Input Control 
                 U4 - Input Control 
               
               
                 Signals 
                 Control Signals 
                 Signals 
                 Signals 
               
               
                   
               
             
            
               
                 A 
                 A, B 
                   
                   
               
               
                 B 
                   
                 A, B 
               
               
                 C 
                 C 
                   
                 INH 
               
               
                 D 
                   
                   
                 A 
               
               
                 E 
               
               
                 F 
                   
                   
                 C 
               
               
                 G 
                   
                   
                 B 
               
               
                   
               
            
           
         
       
     
     In an exemplary embodiment, input control signal INH of U 1  is connected to ground and input control signals C and INH of U 6  are connected ground. 
     In an exemplary embodiment, the switch I/O signals X 0 , X 1 , Y 0 , Y 1 , Z 0  and Z 1  of the digitally controlled analog switches, U 1 , U 6  and U 4 , are provided with the following inputs: 
     
       
         
           
               
               
               
               
               
               
             
               
                   
               
               
                 U1 - 
                 INPUT 
                   
                 INPUT 
                   
                 INPUT 
               
               
                 Switch I/O 
                 For 
                 U6 - Switch 
                 For 
                 U4 - Switch 
                 For 
               
               
                 Signals 
                 U1 
                 I/O Signals 
                 U6 
                 I/O Signals 
                 U4 
               
               
                   
               
             
            
               
                 X0 
                 X of U4 
                 X0 
                 Z of U1 
                 X0 
                 Z of U4 
               
               
                   
                   
                   
                 Y of U4 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                   
               
               
                 U1 - 
                 INPUT 
                   
                 INPUT 
                   
                 INPUT 
               
               
                 Switch I/O 
                 For 
                 U6 - Switch 
                 For 
                 U4 - Switch 
                 For 
               
               
                 Signals 
                 U1 
                 I/O Signals 
                 U6 
                 I/O Signals 
                 U4 
               
               
                   
               
             
            
               
                 X1 
                 V-bat 
                 X1 
                 V-bat 
                 X1 
                 output of 
               
               
                   
                   
                   
                   
                   
                 charge 
               
               
                   
                   
                   
                   
                   
                 pump 3016 
               
               
                 Y0 
                 V-bat 
                 Y0 
                 V-bat 
                 Y0 
                 Z of U4 
               
               
                 Y1 
                 X of U4 
                 Y1 
                 Z of U1 
                 Y1 
                 output of 
               
               
                   
                   
                   
                 Y of U4 
                   
                 charge 
               
               
                   
                   
                   
                   
                   
                 pump 3016 
               
               
                 Z0 
                 GND 
                 Z0 
                 GND 
                 Z0 
                 E of U2 
               
               
                 Z1 
                 X of U4 
                 Z1 
                 GND 
                 Z1 
                 output of 
               
               
                   
                   
                   
                   
                   
                 voltage 
               
               
                   
                   
                   
                   
                   
                 supply 
               
               
                   
                   
                   
                   
                   
                 3018 
               
               
                   
               
            
           
         
       
     
     In an exemplary embodiment, the microcontroller U 2  of the CPU  3012  is a model number PIC16F636 programmable microcontroller, commercially available from Microchip. 
     In an exemplary embodiment, the signal sensor  3014  includes a photodiode D 3  for sensing the transmission of the signals, including the sync signal and/or configuration data, by the signal transmitter  110 . In an exemplary embodiment, the photodiode D 3  is a model BP104FS photodiode, commercially available from Osram. In an exemplary embodiment, the signal sensor  3014  further includes operational amplifiers, U 5 - 1 , U 5 - 2 , and U 3 , and related signal conditioning components, resistors R 2 , R 3 , R 5 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12  and R 13 , capacitors C 1 , C 7 , and C 9 , and schottky diodes, D 1  and D 5 , that may, for example, condition the signal by preventing clipping of the sensed signal by controlling the gain. 
     In an exemplary embodiment, the charge pump  3016  amplifies the magnitude of the output voltage of the battery  120 , using a charge pump, from 3V to −12V. In an exemplary embodiment, the charge pump  3016  includes a MOSFET Q 1 , a schottky diode D 6 , an inductor L 1 , and a zener diode D 7 . In an exemplary embodiment, the output signal of the charge pump  3016  is provided as input signals to switch I/O signals X 1  and Y 1  of the digitally controlled analog switch U 4  of the common shutter controller  3010  and as input voltage VEE to the digitally controlled analog switches U 1 , U 6 , and U 4  of the left shutter controller  3006 , the right shutter controller  3008 , and the common shutter controller  3010 . 
     In an exemplary embodiment, the voltage supply  3018  includes a transistor Q 2 , a capacitor C 5 , and resistors R 1  and R 16 . In an exemplary embodiment, the voltage supply  3018  provides 1V signal as an input signal to switch I/O signal Z 1  of the digitally controlled analog switch U 4  of the common shutter controller  3010 . In an exemplary embodiment, the voltage supply  3018  provides a ground lift. 
     As illustrated in  FIG. 32 , in an exemplary embodiment, during operation of the 3D glasses  3000 , the digitally controlled analog switches, U 1 , U 6  and U 4 , under the control of the control signals A, B, C, D, E, F and G of the CPU  3012 , may provide various voltages across one or both of the left and right shutters,  3002  and  3004 . In particular, the digitally controlled analog switches, U 1 , U 6  and U 4 , under the control of the control signals A, B, C, D, E, F and G of the CPU  3012 , may provide: 1) a positive or negative 15 volts across one or both of the left and right shutters,  3002  and  3004 , 2) a positive or negative 2 volts across one or both of the left and right shutters, 3) a positive or negative 3 volts across one or both of the left and right shutters, and 4) provide 0 volts, i.e., a neutral state, across one or both of the left and right shutters. 
     In an exemplary embodiment, as illustrated in  FIG. 32 , the control signal A controls the operation of left shutter  3002  and the control signal B controls the operation of the right shutter  3004  by controlling the operation of the switches within the digitally controlled analog switches, U 1  and U 6 , respectively, that generate output signals X and Y that are applied across the left and right shutters. In an exemplary embodiment, the control inputs A and B of each of the digitally controlled analog switches U 1  and U 6  are connected together so that switching between two pairs of input signals occurs simultaneously and the selected inputs are forwarded to terminals of the left and right shutters,  3002  and  3004 . In an exemplary embodiment, control signal A from the CPU  3012  controls the first two switches in the digitally controlled analog switch U 1  and control signal B from the CPU controls first two switches in the digitally controlled analog switch U 6 . 
     In an exemplary embodiment, as illustrated in  FIG. 32 , one of the terminals of each of the left and right shutters,  3002  and  3004 , are always connected to 3V. Thus, in an exemplary embodiment, the digitally controlled analog switches U 1 , U 6  and U 4 , under the control of the control signals A, B, C, D, E, F and G of the CPU  3012 , are operated to bring either −12V, 3V, 1V or 0V to the other terminals of the left and right shutters,  3002  and  3004 . As a result, in an exemplary embodiment, the digitally controlled analog switches U 1 , U 6  and U 4 , under the control of the control signals A, B, C, D, E, F and G of the CPU  3012 , are operated to generate a potential difference of 15V, 0V, 2V or 3V across the terminals of the left and right shutters,  3002  and  3004 . 
     In an exemplary embodiment, the third switch of the digitally controlled analog switch U 6  is not used and all of the terminals for the third switch are grounded. In an exemplary embodiment, the third switch of the digitally controlled analog switch U 1  is used for power saving. 
     In particular, in an exemplary embodiment, as illustrated in  FIG. 32 , the control signal C controls the operation of the switch within the digitally controlled analog switch U 1  that generates the output signal Z. As a result, when the control signal C is a digital high value, the input signal INH for the digitally controlled analog switch U 4  is also a digital high value thereby causing all of the output channels of the digitally controlled analog switch U 4  to be off. As a result, when the control signal C is a digital high value, the left and right shutters,  3002  and  3004 , are short circuited thereby permitting half of the charge to be transferred between the shutters thereby saving power and prolonging the life of the battery  120 . 
     In an exemplary embodiment, by using the control signal C to short circuit the left and right shutters,  3002  and  3004 , the high amount of charge collected on one shutter that is in the closed state can be used to partially charge the other shutter just before it goes to the closed state, therefore saving the amount of charge that would otherwise have to be fully provided by the battery  120 . 
     In an exemplary embodiment, when the control signal C generated by the CPU  3012  is a digital high value, for example, the negatively charged plate, −12V, of the left shutter  3002 , then in the closed state and having a 15V potential difference there across, is connected to the more negatively charged plate of the right shutter  3004 , then in the open state and still charged to +1V and having a 2V potential difference there across. In an exemplary embodiment, the positively charged plates on both shutters,  3002  and  3004 , will be charged to +3V. In an exemplary embodiment, the control signal C generated by the CPU  3012  goes to a digital high value for a short period of time near the end of the closed state of the left shutter  3002  and just before the closed state of the right shutter  3004 . When the control signal C generated by the CPU  3012  is a digital high value, the inhibit terminal INH on the digitally controlled analog switch U 4  is also a digital high value. As a result, in an exemplary embodiment, all of the output channels, X, Y and Z, from U 4  are in the off state. This allows the charge stored across the plates of the left and right shutters,  3002  and  3004 , to be distributed between the shutters so that the potential difference across both of the shutter is approximately 17/2V or 8.5V. Since one terminal of the shutters,  3002  and  3004 , is always connected to 3V, the negative terminals of the shutters,  3002  and  3004 , are then at −5.5V. In an exemplary embodiment, the control signal C generated by the CPU  3012  then changes to a digital low value and thereby disconnects the negative terminals of the shutters,  3002  and  3004 , from one another. Then, in an exemplary embodiment, the closed state for the right shutter  3004  begins and the battery  120  further charges the negative terminal of the right shutter, by operating the digitally controlled analog switch U 4 , to −12V. As a result, in an exemplary experimental embodiment, a power savings of approximately 40% was achieved during a normal run mode of operation, as described below with reference to the method  3300 , of the 3D glasses  3000 . 
     In an exemplary embodiment, the control signal C generated by the CPU  3012  is provided as a short duration pulse that transitions from high to low when the control signals A or B, generated by the CPU, transition from high to low or low to high, to thereby start the next left shutter open/right shutter closed or right shutter open/left shutter closed. 
     Referring now to  FIGS. 33 and 34 , in an exemplary embodiment, during the operation of the 3D glasses  3000 , the 3D glasses execute a normal run mode of operation  3300  in which the control signals A, B, C, D, E, F and G generated by the CPU  3012  are used to control the operation of the left and right shutter controllers,  3006  and  3008 , and central shutter controller  3010 , to in turn control the operation of the left and right shutters,  3002  and  3004 , as a function of the type of sync signal detected by the signal sensor  3014 . 
     In particular, in  3302 , if the CPU  3012  determines that the signal sensor  3014  has received a sync signal, then, in  3304 , control signals A, B, C, D, E, F and G generated by the CPU  3012  are used to control the operation of the left and right shutter controllers,  3006  and  3008 , and central shutter controller  3010 , to transfer charge between the left and right shutters,  3002  and  3004 , as described above with reference to  FIG. 32 . 
     In an exemplary embodiment, in  3304 , the control signal C generated by the CPU  3012  is set to a high digital value for approximately 0.2 milliseconds to thereby short circuit the terminals of the left and right shutters,  3002  and  3004 , and thus transfer charge between the left and right shutters. In an exemplary embodiment, in  3304 , the control signal C generated by the CPU  3012  is set to a high digital value for approximately 0.2 milliseconds to thereby short circuit the more negatively charged terminals of the left and right shutters,  3002  and  3004 , and thus transfer charge between the left and right shutters. Thus, the control signal C is provided as a short duration pulse that transitions from high to low when, or before, the control signals A or B transition from high to low or from low to high. As a result, power savings is provided during the operation of the 3D glasses  3000  during the cycle of alternating between open left/closed right and closed left/opened right shutters. 
     The CPU  3012  then determines the type of sync signal received in  3306 . In an exemplary embodiment, a sync signal that includes 2 pulses indicates that the left shutter  3002  should be opened and the right shutter  3004  should be closed while a sync signal that includes 3 pulses indicates that the right shutter should be opened and the left shutter should be closed. In an exemplary embodiment, other different numbers and formats of sync signals may be used to control the alternating opening and closing of the left and right shutters,  3002  and  3004 . 
     If, in  3306 , the CPU  3012  determines that sync signal received indicates that the left shutter  3002  should be opened and the right shutter  3004  should be closed, then the CPU transmits control signals A, B, C, D, E, F and G to the left and right shutter controllers,  3006  and  3008 , and the common shutter controller  3010 , in  3308 , to apply a high voltage across the right shutter  3004  and no voltage followed by a small catch voltage to the left shutter  3002 . In an exemplary embodiment, the magnitude of the high voltage applied across the right shutter  3004  in  3308  is 15 volts. In an exemplary embodiment, the magnitude of the catch voltage applied to the left shutter  3002  in  3308  is 2 volts. In an exemplary embodiment, the catch voltage is applied to the left shutter  3002  in  3308  by controlling the operational state of the control signal D to be low and the operational state of the control signal F, which may be either be low or high, to be high. In an exemplary embodiment, the application of the catch voltage in  3308  to the left shutter  3002  is delayed by a predetermined time period to allow faster rotation of the molecules within the liquid crystal of the left shutter. The subsequent application of the catch voltage, after the expiration of the predetermined time period, prevents the molecules within the liquid crystals in the left shutter  3002  from rotating too far during the opening of the left shutter. In an exemplary embodiment, the application of the catch voltage in  3308  to the left shutter  3002  is delayed by about 1 millisecond. 
     Alternatively, if, in  3306 , the CPU  3012  determines that sync signal received indicates that the left shutter  3002  should be closed and the right shutter  3004  should be opened, then the CPU transmits control signals A, B, C, D, E, F and G to the left and right shutter controllers,  3006  and  3008 , and the common shutter controller  3010 , in  3310 , to apply a high voltage across the left shutter  3002  and no voltage followed by a small catch voltage to the right shutter  3004 . In an exemplary embodiment, the magnitude of the high voltage applied across the left shutter  3002  in  3310  is 15 volts. In an exemplary embodiment, the magnitude of the catch voltage applied to the right shutter  3004  in  3310  is 2 volts. In an exemplary embodiment, the catch voltage is applied to the right shutter  3004  in  3310  by controlling the control signal F to be high and the control signal G to be low. In an exemplary embodiment, the application of the catch voltage in  3310  to the right shutter  3004  is delayed by a predetermined time period to allow faster rotation of the molecules within the liquid crystal of the right shutter. The subsequent application of the catch voltage, after the expiration of the predetermined time period, prevents the molecules within the liquid crystals in the right shutter  3004  from rotating too far during the opening of the right shutter. In an exemplary embodiment, the application of the catch voltage in  3310  to the right shutter  3004  is delayed by about 1 millisecond. 
     In an exemplary embodiment, during the method  3300 , the voltages applied to the left and right shutters,  3002  and  3004 , are alternately positive and negative in subsequent repetitions of the steps  3308  and  3310  in order to prevent damage to the liquid crystal cells of the left and right shutters. 
     Thus, the method  3300  provides a NORMAL or RUN MODE of operation for the 3D glasses  3000 . 
     Referring now to  FIGS. 35 and 36 , in an exemplary embodiment, during operation of the 3D glasses  3000 , the 3D glasses implement a warm up method  3500  of operation in which the control signals A, B, C, D, E, F and G generated by the CPU  3012  are used to control the operation of the left and right shutter controllers,  3006  and  3008 , and central shutter controller  3010 , to in turn control the operation of the left and right shutters,  3002  and  3004 . 
     In  3502 , the CPU  3012  of the 3D glasses checks for a power on of the 3D glasses. In an exemplary embodiment, the 3D glasses  3000  may be powered on either by a user activating a power on switch, by an automatic wakeup sequence, and/or by the signal sensor  3014  sensing a valid sync signal. In the event of a power on of the 3D glasses  3000 , the shutters,  3002  and  3004 , of the 3D glasses may, for example, require a warm-up sequence. The liquid crystal cells of the shutters,  3002  and  3004 , that do not have power for a period of time may be in an indefinite state. 
     If the CPU  3012  of the 3D glasses  3000  detects a power on of the 3D glasses in  3502 , then the CPU applies alternating voltage signals to the left and right shutters,  3002  and  3004 , respectively, in  3504 . In an exemplary embodiment, the voltage applied to the left and right shutters,  3002  and  3004 , is alternated between positive and negative peak values to avoid ionization problems in the liquid crystal cells of the shutter. In an exemplary embodiment, the voltage signals applied to the left and right shutters,  3002  and  3004 , may be at least partially out of phase with one another. In an exemplary embodiment, one or both of the voltage signals applied to the left and right shutters,  3002  and  3004 , may be alternated between a zero voltage and a peak voltage. In an exemplary embodiment, other forms of voltage signals may be applied to the left and right shutters,  3002  and  3004 , such that the liquid crystal cells of the shutters are placed in a definite operational state. In an exemplary embodiment, the application of the voltage signals to the left and right shutters,  3002  and  3004 , causes the shutters to open and close, either at the same time or at different times. 
     During the application of the voltage signals to the left and right shutters,  3002  and  3004 , the CPU  3012  checks for a warm up time out in  3506 . If the CPU  3012  detects a warm up time out in  3506 , then the CPU will stop the application of the voltage signals to the left and right shutters,  3002  and  3004 , in  3508 . 
     In an exemplary embodiment, in  3504  and  3506 , the CPU  3012  applies the voltage signals to the left and right shutters,  3002  and  3004 , for a period of time sufficient to actuate the liquid crystal cells of the shutters. In an exemplary embodiment, the CPU  3012  applies the voltage signals to the left and right shutters,  3002  and  3004 , for a period of two seconds. In an exemplary embodiment, the maximum magnitude of the voltage signals applied to the left and right shutters,  3002  and  3004 , may be 15 volts. In an exemplary embodiment, the time out period in  3506  may be two seconds. In an exemplary embodiment, the maximum magnitude of the voltage signals applied to the left and right shutters,  3002  and  3004 , may be greater or lesser than 15 volts, and the time out period may be longer or shorter. In an exemplary embodiment, during the method  3500 , the CPU  3012  may open and close the left and right shutters,  3002  and  3004 , at a different rate than would be used for viewing a movie. In an exemplary embodiment, in  3504 , the voltage signals applied to the left and right shutters,  3002  and  3004 , do not alternate and are applied constantly during the warm up time period and therefore the liquid crystal cells of the shutters may remain opaque for the entire warm up period. In an exemplary embodiment, the warm-up method  3500  may occur with or without the presence of a synchronization signal. Thus, the method  3500  provides a WARM UP mode of the operation for the 3D glasses  3000 . In an exemplary embodiment, after implementing the warm up method  3500 , the 3D glasses  3000  are placed in a NORMAL MODE, RUN MODE or CLEAR MODE of operation and may then implement the method  3300 . 
     Referring now to  FIGS. 37 and 38 , in an exemplary embodiment, during the operation of the 3D glasses  3000 , the 3D glasses implement a method  3700  of operation in which the control signals A, B, C, D, E, F and G generated by the CPU  3012  are used to control the operation of the left and right shutter controllers,  3006  and  3008 , and the common shutter controller  3010 , to in turn control the operation of the left and right shutters,  3002  and  3004 , as a function of the sync signal received by the signal sensor  3014 . 
     In  3702 , the CPU  3012  checks to see if the sync signal detected by the signal sensor  3014  is valid or invalid. If the CPU  3012  determines that the sync signal is invalid in  3702 , then the CPU applies voltage signals to the left and right shutters,  3002  and  3004 , of the 3D glasses  3000  in  3704 . In an exemplary embodiment, the voltage applied to the left and right shutters,  3002  and  3004 , in  3704 , is alternated between positive and negative peak values to avoid ionization problems in the liquid crystal cells of the shutter. In an exemplary embodiment, the voltage applied to the left and right shutters,  3002  and  3004 , in  3704 , is alternated between positive and negative peak values to provide a square wave signal having a frequency of 60 Hz. In an exemplary embodiment, the square wave signal alternates between +3V and −3V. In an exemplary embodiment, one or both of the voltage signals applied to the left and right shutters,  3002  and  3004 , in  3704 , may be alternated between a zero voltage and a peak voltage. In an exemplary embodiment, other forms, including other frequencies, of voltage signals may be applied to the left and right shutters,  3002  and  3004 , in  3704 , such that the liquid crystal cells of the shutters remain open so that the user of the 3D glasses  3000  can see normally through the shutters. In an exemplary embodiment, the application of the voltage signals to the left and right shutters,  3002  and  3004 , in  3704 , causes the shutters to open. 
     During the application of the voltage signals to the left and right shutters,  3002  and  3004 , in  3704 , the CPU  3012  checks for a clearing time out in  3706 . If the CPU  3012  detects a clearing time out in  3706 , then the CPU  3012  will stop the application of the voltage signals to the shutters,  3002  and  3004 , in  3708 , which may then place the 3D glasses  3000  into an OFF MODE of operation. In an exemplary embodiment, the duration of the clearing time out may, for example, be up to about 4 hours in length. 
     Thus, in an exemplary embodiment, if the 3D glasses  3000  do not detect a valid synchronization signal, they may go to a clear mode of operation and implement the method  3700 . In the clear mode of operation, in an exemplary embodiment, both shutters,  3002  and  3004 , of the 3D glasses  3000  remain open so that the viewer can see normally through the shutters of the 3D glasses. In an exemplary embodiment, a constant voltage is applied, alternating positive and negative, to maintain the liquid crystal cells of the shutters,  3002  and  3004 , of the 3D glasses  3000  in a clear state. The constant voltage could, for example, be 2 volts, but the constant voltage could be any other voltage suitable to maintain reasonably clear shutters. In an exemplary embodiment, the shutters,  3002  and  3004 , of the 3D glasses  3000  may remain clear until the 3D glasses are able to validate an encryption signal. In an exemplary embodiment, the shutters,  3002  and  3004 , of the 3D glasses  3000  may alternately open and close at a rate that allows the user of the 3D glasses to see normally. 
     Thus, the method  3700  provides a method of clearing the operation of the 3D glasses  3000  and thereby provide a CLEAR MODE of operation. 
     Referring now to  FIGS. 39 and 41 , in an exemplary embodiment, during the operation of the 3D glasses  3000 , the 3D glasses implement a method  3900  of operation in which the control signals A, B, C, D, E, F and G generated by the CPU  3012  are used to transfer charge between the shutters,  3002  and  3004 . In  3902 , the CPU  3012  determines if a valid synchronization signal has been detected by the signal sensor  3014 . If the CPU  3012  determines that a valid synchronization signal has been detected by the signal sensor  3014 , then the CPU generates the control signal C in  3904  in the form of a short duration pulse lasting, in an exemplary embodiment, about 200 μs. In an exemplary embodiment, during the method  3900 , the transfer of charge between the shutters,  3002  and  3004 , occurs during the short duration pulse of the control signal C, substantially as described above with reference to  FIGS. 33 and 34 . 
     In  3906 , the CPU  3012  determines if the control signal C has transitioned from high to low. If the CPU  3012  determines that the control signal C has transitioned from high to low, then the CPU changes the state of the control signals A or B in  3908  and then the 3D glasses  3000  may continue with normal operation of the 3D glasses, for example, as described and illustrated above with reference to  FIGS. 33 and 34 . 
     Referring now to  FIGS. 30   a ,  40  and  41 , in an exemplary embodiment, during the operation of the 3D glasses  3000 , the 3D glasses implement a method  4000  of operation in which the control signals RC 4  and RC 5  generated by the CPU  3012  are used to operate the charge pump  3016  during the normal or warm up modes of operation of the 3D glasses  3000 , as described and illustrated above with reference to  FIGS. 32 ,  33 ,  34 ,  35  and  36 . In  4002 , the CPU  3012  determines if a valid synchronization signal has been detected by the signal sensor  3014 . If the CPU  3012  determines that a valid synchronization signal has been detected by the signal sensor  3014 , then the CPU generates the control signal RC 4  in  4004  in the form of a series of short duration pulses. 
     In an exemplary embodiment, the pulses of the control signal RC 4  control the operation of the transistor Q 1  to thereby transfer charge to the capacitor C 13  until the potential across the capacitor reaches a predetermined level. In particular, when the control signal RC 4  switches to a low value, the transistor Q 1  connects the inductor L 1  to the battery  120 . As a result, the inductor L 1  stores energy from the battery  120 . Then, when the control signal RC 4  switches to a high value, the energy that was stored in the inductor L 1  is transferred to the capacitor C 13 . Thus, the pulses of the control signal RC 4  continually transfer charge to the capacitor C 13  until the potential across the capacitor C 13  reaches a predetermined level. In an exemplary embodiment, the control signal RC 4  continues until the potential across the capacitor C 13  reaches −12V. 
     In an exemplary embodiment, in  4006 , the CPU  3012  generates a control signal RC 5 . As a result, an input signal RA 3  is provided having a magnitude that decreases as the potential across the capacitor C 13  increases. In particular, when the potential across the capacitor C 13  approaches the predetermined value, the zener diode D 7  starts to conduct current thereby reducing the magnitude of the input control signal RA 3 . In  4008 , the CPU  3012  determines if the magnitude of the input control signal RA 3  is less than a predetermined value. If the CPU  3012  determines that the magnitude of the input control signal RA 3  is less than the predetermined value, then, in  4010 , the CPU stops generating the control signals RC 4  and RC 5 . As a result, the transfer of charge to the capacitor C 13  stops. 
     In an exemplary embodiment, the method  4000  may be implemented after the method  3900  during operation of the 3D glasses  3000 . 
     Referring now to  FIGS. 30   a ,  42  and  43 , in an exemplary embodiment, during the operation of the 3D glasses  3000 , the 3D glasses implement a method  4200  of operation in which the control signals A, B, C, D, E, F, G, RA 4 , RC 4  and RC 5  generated by the CPU  3012  are used to determine the operating status of the battery  120  when the 3D glasses  3000  have been switched to an off condition. In  4202 , the CPU  3012  determines if the 3D glasses  3000  are off or on. If the CPU  3012  determines that the 3D glasses  3000  are off, then the CPU determines, in  4204 , if a predetermined timeout period has elapsed in  4204 . In an exemplary embodiment, the timeout period is 2 seconds in length. 
     If the CPU  3012  determines that the predetermined timeout period has elapsed, then the CPU determines, in  4206 , if the number of synchronization pulses detected by the signal sensor  3014  within a predetermined prior time period exceeds a predetermined value. In an exemplary embodiment, in  4206 , predetermined prior time period is a time period that has elapsed since the most recent replacement of the battery  120 . 
     If the CPU  3012  determines that the number of synchronization pulses detected by the signal sensor  3014  within a predetermined prior time period does exceed a predetermined value, then the CPU, in  4208 , generates control signal E as a short duration pulse, in  4210 , provides the control signal RA 4  as a short duration pulse to the signal sensor  3014 , and, in  4212 , toggles the operational state of the control signals A and B, respectively. In an exemplary embodiment, if the number of synchronization pulses detected by the signal sensor  3014  within a predetermined prior time period does exceed a predetermined value, then this may indicate that the remaining power in the battery  120  is low. 
     Alternatively, if the CPU  3012  determines that the number of synchronization pulses detected by the signal sensor  3014  within a predetermined prior time period does not exceed a predetermined value, then the CPU, in  4210 , provides the control signal RA 4  as a short duration pulse to the signal sensor  3014 , and, in  4212 , toggles the operational state of the control signals A and B, respectively. In an exemplary embodiment, if the number of synchronization pulses detected by the signal sensor  3014  within a predetermined prior time period does not exceed a predetermined value, then this may indicate that the remaining power in the battery  120  is not low. 
     In an exemplary embodiment, the combination of the control signals A and B toggling and the short duration pulse of the control signal E, in  4208  and  4212 , causes the shutters,  3002  and  3004 , of the 3D glasses  3000  to be closed, except during the short duration pulse of the control signal E. As a result, in an exemplary embodiment, the shutters,  3002  and  3004 , provide a visual indication to the user of the 3D glasses  3000  that the power remaining within the battery  120  is low by flashing the shutters of the 3D glasses open for a short period of time. In an exemplary embodiment, providing the control signal RA 4  as a short duration pulse to the signal sensor  3014 , in  4210 , permits the signal sensor to search for and detect synchronization signals during the duration of the pulse provided. 
     In an exemplary embodiment, the toggling of the control signals A and B, without also providing the short duration pulse of the control signal E, causes the shutters,  3002  and  3004 , of the 3D glasses  3000  to remain closed. As a result, in an exemplary embodiment, the shutters,  3002  and  3004 , provide a visual indication to the user of the 3D glasses  3000  that the power remaining within the battery  120  is not low by not flashing the shutters of the 3D glasses open for a short period of time. 
     In embodiments that lack a chronological clock, time may be measured in terms of sync pulses. The CPU  3012  may determine time remaining in the battery  120  as a factor of the number of sync pulses for which the battery may continue to operate and then provide a visual indication to the user of the 3D glasses  3000  by flashing the shutters,  3002  and  3004 , open and closed. 
     Referring now to  FIGS. 44-55 , in an exemplary embodiment, one or more of the 3D glasses  104 ,  1800  and  3000  include a frame front  4402 , a bridge  4404 , right temple  4406 , and a left temple  4408 . In an exemplary embodiment, the frame front  4402  houses the control circuitry and power supply for one or more of the 3D glasses  104 ,  1800  and  3000 , as described above, and further defines right and left lens openings,  4410  and  4412 , for holding the right and left ISS shutters described above. In some embodiments, the frame front  4402  wraps around to form a right wing  4402   a  and a left wing  4402   b . In some embodiments, at least part of the control circuitry for the 3D glasses  104 ,  1800  and  3000  are housed in either or both wings  4402   a  and  4402   b.    
     In an exemplary embodiment, the right and left temples,  4406  and  4408 , extend from the frame front  4402  and include ridges,  4406   a  and  4408   a , and each have a serpentine shape with the far ends of the temples being spaced closer together than at their respective connections to the frame front. In this manner, when a user wears the 3D glasses  104 ,  1800  and  3000 , the ends of the temples,  4406  and  4408 , hug and are held in place on the user&#39;s head. In some embodiments, the spring rate of the temples,  4406  and  4408 , is enhanced by the double bend while the spacing and depth of the ridges,  4406   a  and  4408   a , control the spring rate. As shown in  FIG. 55 , some embodiments do not use a double bended shape but, rather, use a simple curved temple  4406  and  4408 . 
     Referring now to  FIGS. 48-55 , in an exemplary embodiment, the control circuitry for one or more of the 3D glasses  104 ,  1800  and  3000  is housed in the frame front, which includes the right wing  4402   a , and the battery is housed in the right wing  4402   a . Furthermore, in an exemplary embodiment, access to the battery  120  of the 3D glasses  3000  is provided through an opening, on the interior side of the right wing  4402   a , that is sealed off by a cover  4414  that includes an o-ring seal  4416  for mating with and sealingly engaging the right wing  4402   a.    
     Referring to  FIGS. 49-55 , in some embodiments, the battery is located within a battery cover assembly formed by cover  4414  and cover interior  4415 . Battery cover  4414  may be attached to battery cover interior  4415  by, for example, ultra-sonic welding. Contacts  4417  may stick out from cover interior  4415  to conduct electricity from the battery  120  to contacts located, for example, inside the right wing  4402   a.    
     Cover interior  4415  may have circumferentially spaced apart radial keying elements  4418  on an interior portion of the cover. Cover  4414  may have circumferentially spaced apart dimples  4420  positioned on an exterior surface of the cover. 
     In an exemplary embodiment, as illustrated in  FIGS. 49-51 , the cover  4414  may be manipulated using a key  4422  that includes a plurality of projections  4424  for mating within and engaging the dimples  4420  of the cover. In this manner, the cover  4414  may be rotated relative to the right wing  4402   a  of the 3D glasses  104 ,  1800  and  3000  from a closed (or locked) position to an open (or unlocked) position. Thus, the control circuitry and battery of the 3D glasses  104 ,  1800  and  3000  may be sealed off from the environment by the engagement of the cover  4414  with the right wing  4402   a  of the 3D glasses  3000  using the key  4422 . Referring to  FIG. 55 , in another embodiment, key  4426  may be used. 
     Referring now to  FIG. 56 , an exemplary embodiment of a signal sensor  5600  includes a narrow band pass filter  5602  that is operably coupled to a decoder  5604 . The signal sensor  5600  in turn is operably coupled to a CPU  5604 . The narrow band pass filter  5602  may be an analog and/or digital band pass filter that may have a pass band suitable for permitting a synchronous serial data signal to pass therethrough while filtering out and removing out of band noise. 
     In an exemplary embodiment, the CPU  5604  may, for example, be the CPU  114 , the CPU  1810 , or the CPU  3012 , of the 3D glasses,  104 ,  1800 , or  3000 . 
     In an exemplary embodiment, during operation, the signal sensor  5600  receives a signal from a signal transmitter  5606 . In an exemplary embodiment, the signal transmitter  5606  may, for example, be the signal transmitter  110 . 
     In an exemplary embodiment, the signal  5700  transmitted by the signal transmitter  5606  to the signal sensor  5600  includes one or more data bits  5702  that are each preceded by a clock pulse  5704 . In an exemplary embodiment, during operation of the signal sensor  5600 , because each bit  5702  of data is preceded by a clock pulse  5704 , the decoder  5604  of the signal sensor can readily decode long data bit words. Thus, the signal sensor  5600  is able to readily receive and decode synchronous serial data transmissions from the signal transmitter  5606 . By contrast, long data bit words, that are asynchronous data transmissions, are typically difficult to transmit and decode in an efficient and/or error free fashion. Therefore, the signal sensor  5600  provides an improved system for receiving data transmissions. Further, the use of synchronous serial data transmission in the operation of the signal sensor  5600  ensures that long data bit words may be readily decoded. 
     Referring to  FIG. 58 , an exemplary embodiment of a system  5800  for viewing 3D images is substantially identical to the system  100 , except as noted below. In an exemplary embodiment, the system  5800  includes a display device  5802 , having an internal clock  5802   a , that is operably coupled to a signal transmitter  5804 . 
     In an exemplary embodiment, the display device  5802  may, for example, be a television, movie screen, liquid crystal display, computer monitor, or other display device, adapted to display, for example, left and right images intended for viewing by the left and right eyes, respectively, of a user of the system  5800 . In an exemplary embodiment, a signal transmitter  5804  is operably coupled to the display device  5802  that transmits signals to the signal sensor  112  of the 3D glasses  104  for controlling the operation of the 3D glasses. In an exemplary embodiment, the signal transmitter  5804  is adapted to transmit signals such as, for example, electromagnetic, infrared, acoustic, and/or radio frequency signals that may or may not be transmitted through an insulated conductor and/or through free space. 
     Referring to  FIG. 59 , in an exemplary embodiment, the system  5800  implements a method  5900  of operation in which, in  5902 , the system determines if the operation of the 3D glasses  104  with the display device  5802  should be initialized. In an exemplary embodiment, the system  5800  may determine that the operation of the 3D glasses  104  with the display device  5802  should be initialized if, for example, the power supply for either device is cycled from off to on or if the user of the system selects an initialization of operation of the 3D glasses with the display device  5802 . 
     If the system determines that the operation of the 3D glasses  104  with the display device  5802  should be initialized in  5902 , then, in  5904 , an information word is transmitted from the display device  5802  using the signal transmitter  5804  and received by the signal sensor  112 . In an exemplary embodiment, the information word may include one or more of the following: 1) the type of display device, 2) the operating frequency of the display device, 3) the opening and closing sequence of the left and right shutters,  106  and  108 , and 4) the 3D display format that will be used by the display device  5802 . In an exemplary embodiment, the information word is then used by the 3D glasses  104  to control the operation of the left and right shutters,  106  and  108 , to permit the wearer of the 3D glasses to view 3D images by viewing the display device  5802 . In an exemplary embodiment, the information word is also used initially to synchronize the clock  5802   a  of the display device  5802  with the clock  114   a  of the CPU  114  of the 3D glasses. In this manner, the opening and closing of the left and right shutters,  106  and  108 , may be initially synchronized with the corresponding images intended for viewing through the respective shutters. 
     In an exemplary embodiment, the system  5800  then determines if a time out period has expired in  5906 . If the time out period has expired, then, in  5908 , the transmitter  5804  then transmits a synchronization signal to the signal sensor  112 . In an exemplary embodiment, the synchronization signal includes a synchronization pulse, a time of transmission of the synchronization signal and a time delay of the transmission of the synchronization signal. In this manner, the synchronization signal is used to resynchronize the clock  5802   a  of the display device  5802  with the clock  114   a  of the CPU  114  of the 3D glasses. In this manner, the opening and closing of the left and right shutters,  106  and  108 , may be resynchronized with the corresponding images intended for viewing through the respective shutters. 
     In an exemplary embodiment, if the time delay of the transmission of the synchronization signal is anything other than a zero value, the non-zero value of the time delay of the transmission of the synchronization signal may then be used by the CPU  114  of the 3D glasses  104  to correctly synchronize the clock  114   a  of the CPU with the clock  5802   a  of the display device  5802 . In an exemplary embodiment, the time delay of the transmission of the synchronization signal may be a non-zero value if, for example, there was a time delay within the signal transmitter  5804  that affected the time of transmission of the synchronization signal to the signal sensor  112 . In this manner, the method  5800  may permit effective synchronization of the clock  114   a  of the CPU with the clock  5802   a  of the display device  5802  in a radio frequency communication protocol such as Bluetooth. 
     In an exemplary embodiment, the system  5800  and/or method  5900  may include, or omit, one or more aspects of one or more of the exemplary embodiments. 
     Referring now to  FIG. 60 , a system  6000  for viewing 3D images includes a display device  6002  having a conventional liquid crystal display (“LCD”)  6002   a  and a conventional back light  6002   b  for the LCD. The general design and operation of display device  6002  is considered well known in the art, except as noted below. A pair of 3D shutter glasses  6004  may be used to view images displayed on the LCD  6002   a  that may include images intended for viewing by the left or the right eye of the wearer of the 3D shutter glasses. In an exemplary embodiment, the 3D shutter glasses  6004  may be conventional in design and operation, or may include one or more aspects of the 3D shutter glasses,  104 ,  1800 , and  3000 , and may be operated using one or more of the exemplary methods of the present disclosure. 
     One of the problems with using an LCD display to view 3D images is that an entire left or right image is not displayed on the LCD display at any given time. Instead, the left or right image is written to the LCD display one line at a time starting at the top of the LCD display such that, at any given moment in time, a new image is displayed at the top of the LCD display while the old image is displayed at the bottom of the LCD display. The line of demarcation between the two images on the LCD display moves from the top to the bottom over time until it reaches the bottom and then the process repeats. Normally the update process is stretched across the entire image display time interval so that the only time that just a single left or right image is displayed on the LCD display at one time is just as one update is completed and before the next one begins. This is the only time that a viewer can look at the LCD display using 3D shutter glasses and not see just a single image—a necessity if crosstalk between adjacent images is to be avoided. As will be recognized by persons having ordinary skill in the art crosstalk between adjacent images results in a composite image, i.e., one including parts of both adjacent displayed images, being viewed by the user of the 3D shutter glasses. 
     Referring to  FIG. 61 , in an exemplary embodiment, during the operation of the system  6000 , the system implements a method of operation in which left and right images are displayed on the LCD  6002   a  in the following sequence: LEFT, LEFT, RIGHT, RIGHT. In an exemplary embodiment, the two displayed LEFT images may be identical and the two displayed RIGHT images may be identical. During the display of the LEFT and RIGHT images on the LCD  6002   a , the 3D shutter glasses  6004  are operated such that the left shutter is open and the right shutter is closed during the display of the LEFT images on the LCD  6002   a , and the left shutter is closed and the right shutter is open during the display of the RIGHT images on the LCD. In an exemplary embodiment, the backlight  6002   b  is turned off around the transitions of the displayed images from a LEFT image to a RIGHT image, and vice versa. As a result, cross talk between LEFT and RIGHT images does not occur when viewed by the user of the 3D shutter glasses  6004 . 
     More generally, the teachings of the method illustrated and described with reference to  FIG. 61  may be extended such that whenever cross talk between images displayed on the LCD  6002   a , the backlight  6002   b  may be turned off around such corresponding transitions between adjacent images to thereby prevent cross talk between LEFT and RIGHT images does not occur when viewed by the user of the 3D shutter glasses  6004 . 
     One of the other problems with LCD displays is that they are typically polarized. Thus, in an exemplary embodiment, the polarization of the left and right shutters of the 3D shutter glasses  6004  are substantially the same as the polarization of the LCD  6002   a.    
     In an exemplary embodiment, during the operation of the system  6000 , the images displayed on the LCD  6002   a  are updated 240 times a second. Furthermore, in an exemplary embodiment, during the operation of the system  6000 , two LEFT images are displayed in a row on the LCD  6002   a  and then two RIGHT images are displayed in a row on the LCD. As a result, this is equivalent to having a 120 Hz update rate. In an exemplary embodiment, this operation provides 50% of the time to look at a single LEFT or RIGHT image. In an exemplary embodiment, turning off the back light  6002   b  can done essentially instantaneously so there is no concern with regard to the switching time of the left and right shutters of the 3D glasses  6004 . As a result, it may be possible to overdrive the backlight  6002   b  to get some of the lost light back. 
     Furthermore, if in the alternative, you attempted to eliminate cross talk between displayed images by closing both of shutters of the 3D glasses  6004  during the corresponding transition, not only would you not be able to see the LCD  6002   a , but you could not see anything else either. As a result, in such an alternative embodiment, the room lighting is attenuated by about 95%. By contrast, using the method illustrated and described above with reference to  FIG. 61 , the room lighting is attenuated by only about 75%. 
     In an exemplary embodiment, the system  6000  and/or method  6100  may include, or omit, one or more aspects of one or more of the exemplary embodiments. 
     A liquid crystal shutter has a liquid crystal that rotates by applying an electrical voltage to the liquid crystal and then the liquid crystal achieves a light transmission rate of at least twenty-five percent in less than one millisecond. When the liquid crystal rotates to a point having maximum light transmission, a device stops the rotation of the liquid crystal at the point of maximum light transmission and then holds the liquid crystal at the point of maximum light transmission for a period of time. A computer program installed on a machine readable medium may be used to facilitate any of these embodiments. 
     A system presents a three dimensional video image by using a pair of liquid crystal shutter glasses that have a first and a second liquid crystal shutter, and a control circuit adapted to open the first liquid crystal shutter. The first liquid crystal shutter can open to a point of maximum light transmission in less than one millisecond, at which time the control circuit may apply a catch voltage to hold the first liquid crystal shutter at the point of maximum light transmission for a first period of time and then close the first liquid crystal shutter. Next, the control circuit opens the second liquid crystal shutter, wherein the second liquid crystal shutter opens to a point of maximum light transmission in less than one millisecond, and then applies a catch voltage to hold the second liquid crystal shutter at the point of maximum light transmission for a second period of time, and then close the second liquid crystal shutter. The first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer. A computer program installed on a machine readable medium may be used to facilitate any of the embodiments described herein. 
     In an exemplary embodiment, the control circuit is adapted to use a synchronization signal to determine the first and second period of time. In an exemplary embodiment, the catch voltage is two volts. 
     In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. 
     In an exemplary embodiment, an emitter provides a synchronization signal and the synchronization signal causes the control circuit to open one of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal comprises an encrypted signal. In an exemplary embodiment, the control circuit of the three dimensional glasses will only operate after validating an encrypted signal. 
     In an exemplary embodiment, the control circuit has a battery sensor and may be adapted to provide an indication of a low battery condition. The indication of a low battery condition may be a liquid crystal shutter that is closed for a period of time and then open for a period of time. 
     In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after detecting the synchronization signal. 
     In an exemplary embodiment, the encrypted signal will only operate a pair of liquid crystal glasses having a control circuit adapted to receive the encrypted signal. 
     In an exemplary embodiment, a test signal operates the liquid crystal shutters at a rate that is visible to a person wearing the pair of liquid crystal shutter glasses. 
     In an exemplary embodiment, a pair of glasses has a first lens that has a first liquid crystal shutter and a second lens that has a second liquid crystal shutter. Both liquid crystal shutters have a liquid crystal that can open in less than one millisecond and a control circuit that alternately opens the first and second liquid crystal shutters. When the liquid crystal shutter opens, the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter. 
     In an exemplary embodiment, a catch voltage holds the liquid crystal at the point of maximum light transmission. The point of maximum light transmission may transmit more than thirty two percent of light. 
     In an exemplary embodiment, an emitter that provides a synchronization signal and the synchronization signal causes the control circuit to open one of the liquid crystal shutters. In some embodiments, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the control circuit will only operate after validating the encrypted signal. In an exemplary embodiment, the control circuit includes a battery sensor and may be adapted to provide an indication of a low battery condition. The indication of a low battery condition could be a liquid crystal shutter that is closed for a period of time and then open for a period of time. In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after it detects the synchronization signal. 
     The encrypted signal may only operate a pair of liquid crystal glasses that has a control circuit adapted to receive the encrypted signal. 
     In an exemplary embodiment, a test signal operates the liquid crystal shutters at a rate that is visible to a person wearing the pair of liquid crystal shutter glasses. 
     In an exemplary embodiment, a three dimensional video image is presented to a viewer by using liquid crystal shutter eyeglasses, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter, then opening the second liquid crystal shutter in less than one millisecond, and then holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. The first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer. 
     In an exemplary embodiment, the liquid crystal shutter is held at the point of maximum light transmission by a catch voltage. The catch voltage could be two volts. In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. 
     In an exemplary embodiment, an emitter provides a synchronization signal that causes the control circuit to open one of the liquid crystal shutters. In some embodiments, the synchronization signal comprises an encrypted signal. 
     In an exemplary embodiment, the control circuit will only operate after validating the encrypted signal. 
     In an exemplary embodiment, a battery sensor monitors the amount of power in the battery. In an exemplary embodiment, the control circuit is adapted to provide an indication of a low battery condition. The indication of a low battery condition may be a liquid crystal shutter that is closed for a period of time and then open for a period of time. 
     In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the encrypted signal will only operate a pair of liquid crystal glasses that has a control circuit adapted to receive the encrypted signal. 
     In an exemplary embodiment, a test signal operates the liquid crystal shutters at a rate that is visible to a person wearing the pair of liquid crystal shutter glasses. 
     In an exemplary embodiment, a system for providing three dimensional video images may include a pair of glasses that has a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter. The liquid crystal shutters may have a liquid crystal and an may be opened in less than one millisecond. A control circuit may alternately open the first and second liquid crystal shutters, and hold the liquid crystal orientation at a point of maximum light transmission until the control circuit closes the shutter. Furthermore, the system may have a low battery indicator that includes a battery, a sensor capable of determining an amount of power remaining in the battery, a controller adapted to determine whether the amount of power remaining in the battery is sufficient for the pair of glasses to operate longer than a predetermined time, and an indicator to signal a viewer if the glasses will not operate longer than the predetermined time. In an exemplary embodiment, the low battery indicator is opening and closing the left and right liquid crystal shutters at a predetermined rate. In an exemplary embodiment, the predetermined amount of time is longer than three hours. In an exemplary embodiment, the low battery indicator may operate for at least three days after determining that the amount of power remaining in the battery is not sufficient for the pair of glasses to operate longer than the predetermined amount of time. In an exemplary embodiment, the controller may determine the amount of power remaining in the battery by measuring time by the number of synchronization pulses remaining in the battery. 
     In an exemplary embodiment for providing a three dimensional video image, the image is provided by having a pair of three dimensional viewing glasses that includes a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. The first period of time corresponds to the presentation of an image for a first eye of the viewer and the second period of time corresponds to the presentation of an image for the second eye of the viewer. In this exemplary embodiment, the three dimensional viewing glasses sense the amount of power remaining in the battery, determine whether the amount of power remaining in the battery is sufficient for the pair of glasses to operate longer than a predetermined time, and then indicate a low-battery signal to a viewer if the glasses will not operate longer than the predetermined time. The indicator may be opening and closing the lenses at a predetermined rate. The predetermined amount of time for the battery to last could be more than three hours. In an exemplary embodiment, the low battery indicator operates for at least three days after determining the amount of power remaining in the battery is not sufficient for the pair of glasses to operate longer than the predetermined amount of time. In an exemplary embodiment, the controller determines the amount of power remaining in the battery by measuring time by the number of synchronization pulses that the battery can last for. 
     In an exemplary embodiment, for providing three dimensional video images, the system includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond. A control circuit may alternately open the first and second liquid crystal shutters, and the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter. Furthermore, a synchronization device that includes a signal transmitter that sends a signal corresponding to an image presented for a first eye, a signal receiver sensing the signal, and a control circuit adapted to open the first shutter during a period of time in which the image is presented for the first eye. In an exemplary embodiment, the signal is an infrared light. 
     In an exemplary embodiment, the signal transmitter projects the signal toward a reflector, the signal is reflected by the reflector, and the signal receiver detects the reflected signal. In some embodiments, the reflector is a movie theater screen. In an exemplary embodiment, the signal transmitter receives a timing signal from an image projector such as the movie projector. In an exemplary embodiment, the signal is a radio frequency signal. In an exemplary embodiment, the signal is a series of pulses at a predetermined interval. In an exemplary embodiment, where the signal is a series of pulses at a predetermined interval, the first predetermined number of pulses opens the first liquid crystal shutter and a second predetermined number of pulses opens the second liquid crystal shutter. 
     In an exemplary embodiment for providing a three dimensional video image, the method of providing the image includes: having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. The first period of time corresponds to the presentation of an image for the left eye of a viewer and the second period of time corresponds to the presentation of an image for the right eye of a viewer. The signal transmitter can transmit a signal corresponding to the image presented for a left eye, and, sensing the signal the three dimensional view glasses can use the signal to determine when to open the first liquid crystal shutter. In an exemplary embodiment, the signal is an infrared light. In an exemplary embodiment, the signal transmitter projects the signal toward a reflector which reflects the signal toward the three dimensional viewing glasses, and the signal receiver in the glasses detects the reflected signal. In an exemplary embodiment, the reflector is a movie theater screen. 
     In an exemplary embodiment, the signal transmitter receives a timing signal from an image projector. In an exemplary embodiment, the signal is a radio frequency signal. In an exemplary embodiment, the signal could be a series of pulses at a predetermined interval. A first predetermined number of pulses could open the first liquid crystal shutter and a second predetermined number of pulses could open the second liquid crystal shutter. 
     In an exemplary embodiment of a system for providing three dimensional video images, a pair of glasses has a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond. A control circuit alternately opens the first and second liquid crystal shutters, and the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter. In an exemplary embodiment, a synchronization system comprising a reflection device located in front of the pair of glasses, and a signal transmitter sending a signal towards the reflection device. The signal corresponds to an image presented for a first eye of a viewer. A signal receiver senses the signal reflected from the reflection device, and then a control circuit opens the first shutter during a period of time in which the image is presented for the first eye. 
     In an exemplary embodiment, the signal is an infrared light. In an exemplary embodiment, the reflector is a movie theater screen. In an exemplary embodiment, the signal transmitter receives a timing signal from an image projector. The signal may a series of pulses at a predetermined interval. In an exemplary embodiment, the signal is a series of pulses at a predetermined interval and the first predetermined number of pulses opens the first liquid crystal shutter and the second predetermined number of pulses opens the second liquid crystal shutter. 
     In an exemplary embodiment for providing a three dimensional video image, the image can be provided by having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, and then holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. The first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer. In an exemplary embodiment, the transmitter transmits an infrared signal corresponding to the image presented for a first eye. The three dimensional viewing glasses sense the infrared signal, and then use the infrared signal to trigger the opening of the first liquid crystal shutter. In an exemplary embodiment, the signal is an infrared light. In an exemplary embodiment, the reflector is a movie theater screen. In an exemplary embodiment, the signal transmitter receives a timing signal from an image projector. The timing signal could be a series of pulses at a predetermined interval. In some embodiments, a first predetermined number of pulses opens the first liquid crystal shutter and a second predetermined number of pulses opens the second liquid crystal shutter. 
     In an exemplary embodiment, a system for providing three dimensional video images includes a pair of glasses that have a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond. The system could also have a control circuit that alternately opens the first and second liquid crystal shutters, and hold the liquid crystal orientation at a point of maximum light transmission until the control circuit closes the shutter. The system may also have a test system comprising a signal transmitter, a signal receiver, and a test system control circuit adapted to open and close the first and second shutters at a rate that is visible to a viewer. In an exemplary embodiment, the signal transmitter does not receive a timing signal from a projector. In an exemplary embodiment, the signal transmitter emits an infrared signal. The infrared signal could be a series of pulses. In another exemplary embodiment, the signal transmitter emits an radio frequency signal. The radio frequency signal could be a series of pulses. 
     In an exemplary embodiment of a method for providing a three dimensional video image, the method could include having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, and holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. In an exemplary embodiment, the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer. In an exemplary embodiment, a transmitter could transmit a test signal towards the three dimensional viewing glasses, which then receive the test signal with a sensor on the three dimensional glasses, and then use a control circuit to open and close the first and second liquid crystal shutters as a result of the test signal, wherein the liquid crystal shutters open and close at a rate that is observable to a viewer wearing the glasses. 
     In an exemplary embodiment the signal transmitter does not receive a timing signal from a projector. In an exemplary embodiment, the signal transmitter emits an infrared signal, which could be a series of pulses. In an exemplary embodiment, the signal transmitter emits an radio frequency signal. In an exemplary embodiment, the radio frequency signal is a series of pulses. 
     An exemplary embodiment of a system for providing three dimensional video images could include a pair of glasses comprising a first lens that has a first liquid crystal shutter and a second lens that has a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond. The system could also have a control circuit that alternately opens the first and second liquid crystal shutters, holds the liquid crystal orientation at a point of maximum light transmission and then close the shutter. In an exemplary embodiment, an auto-on system comprising a signal transmitter, a signal receiver, and wherein the control circuit is adapted to activate the signal receiver at a first predetermined time interval, determine if the signal receiver is receiving a signal from the signal transmitter, deactivate the signal receiver if the signal receiver does not receive the signal from the signal transmitter within a second period of time, and alternately open the first and second shutters at an interval corresponding to the signal if the signal receiver does receive the signal from the signal transmitter. 
     In an exemplary embodiment, the first period of time is at least two seconds and the second period of time could be no more than 100 milliseconds. In an exemplary embodiment, the liquid crystal shutters remain open until the signal receiver receives a signal from the signal transmitter. 
     In an exemplary embodiment, a method for providing a three dimensional video image could include having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, and holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. In an exemplary embodiment, the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer. In an exemplary embodiment, the method could include activating a signal receiver at a first predetermined time interval, determining if the signal receiver is receiving a signal from the signal transmitter, deactivating the signal receiver if the signal receiver does not receive the signal from the signal transmitter within a second period of time, and opening and closing the first and second shutters at an interval corresponding to the signal if the signal receiver does receive the signal from the signal transmitter. In an exemplary embodiment, the first period of time is at least two seconds. In an exemplary embodiment, the second period of time is no more than 100 milliseconds. In an exemplary embodiment, the liquid crystal shutters remain open until the signal receiver receives a signal from the signal transmitter. 
     In an exemplary embodiment, a system for providing three dimensional video images could include a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond. It could also have a control circuit that can alternately open the first and second liquid crystal shutters, and hold the liquid crystal orientation at a point of maximum light transmission until the control circuit closes the shutter. In an exemplary embodiment, the control circuit is adapted to hold the first liquid crystal shutter and the second liquid crystal shutter open. In an exemplary embodiment, the control circuit holds the lenses open until the control circuit detects a synchronization signal. In an exemplary embodiment, the voltage applied to the liquid crystal shutters alternates between positive and negative. 
     In one embodiment of a device for providing a three dimensional video image, a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, wherein the first liquid crystal shutter can open in less than one millisecond, wherein the second liquid crystal shutter can open in less than one millisecond, open and close the first and second liquid crystal shutters at a rate that makes the liquid crystal shutters appear to be clear lenses. In one embodiment, the control circuit holds the lenses open until the control circuit detects a synchronization signal. In one embodiment, the liquid crystal shutters alternates between positive and negative. 
     In an exemplary embodiment, a system for providing three dimensional video images could include a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond. It could also include a control circuit that alternately opens the first and second liquid crystal shutters and hold the liquid crystal at a point of maximum light transmission until the control circuit closes the shutter. In an exemplary embodiment, an emitter could provide a synchronization signal where a portion of the synchronization signal is encrypted. A sensor operably connected to the control circuit could be adapted to receive the synchronization signal, and the first and second liquid crystal shutters could open and close in a pattern corresponding to the synchronization signal only after receiving an encrypted signal. 
     In an exemplary embodiment, the synchronization signal is a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal is a series of pulses at a predetermined interval and a first predetermined number of pulses opens the first liquid crystal shutter and a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, a portion of the series of pulses is encrypted. In an exemplary embodiment, the series of pulses includes a predetermined number of pulses that are not encrypted followed by a predetermined number of pulses that are encrypted. In an exemplary embodiment, the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving two consecutive encrypted signals. 
     In an exemplary embodiment of a method for providing a three dimensional video image, the method could include having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, and holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time. In an exemplary embodiment, the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer. In an exemplary embodiment, an emitter provides a synchronization signal wherein a portion of the synchronization signal is encrypted. In an exemplary embodiment, a sensor is operably connected to the control circuit and adapted to receive the synchronization signal, and the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving an encrypted signal. 
     In an exemplary embodiment, the synchronization signal is a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal is a series of pulses at a predetermined interval and wherein a first predetermined number of pulses opens the first liquid crystal shutter and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, a portion of the series of pulses is encrypted. In an exemplary embodiment, the series of pulses includes a predetermined number of pulses that are not encrypted followed by a predetermined number of pulses that are encrypted. In an exemplary embodiment, the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving two consecutive encrypted signals. 
     A method for rapidly opening a liquid crystal shutter for use in 3D glasses has been described that includes causing the liquid crystal to rotate to an open position, the liquid crystal achieving a light transmission rate of at least twenty-five percent in less than one millisecond, waiting until the liquid crystal rotates to a point having maximum light transmission; stopping the rotation of the liquid crystal at the point of maximum light transmission; and holding the liquid crystal at the point of maximum light transmission for a period of time. In an exemplary embodiment, the system includes a pair of liquid crystal shutters having corresponding first and a second liquid crystal shutters, and a control circuit adapted to open the first liquid crystal shutter, wherein the first liquid crystal shutter opens to a point of maximum light transmission in less than one millisecond, apply a catch voltage to hold the first liquid crystal shutter at the point of maximum light transmission for a first period of time, then close the first liquid crystal shutter, open the second liquid crystal shutter, wherein the second liquid crystal shutter opens to a point of maximum light transmission in less than one millisecond, apply a catch voltage to hold the second liquid crystal shutter at the point of maximum light transmission for a first period of time, and then close the second liquid crystal shutter; wherein the first period of time corresponds to the presentation of an image for a first eye of the user and the second period of time corresponds to the presentation of an image for a second eye of the user. In an exemplary embodiment, the control circuit is adapted to use a synchronization signal to determine the first and second period of time. In an exemplary embodiment, the catch voltage is two volts. In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. In an exemplary embodiment, the system further includes an emitter that provides a synchronization signal and wherein the synchronization signal causes the control circuit to open one of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the control circuit will only operate after validating the encrypted signal. In an exemplary embodiment, the system further includes a battery sensor. In an exemplary embodiment, the control circuit is adapted to provide an indication of a low battery condition. In an exemplary embodiment, the indication of a low battery condition comprises a liquid crystal shutter that is closed for a period of time and then open for a period of time. In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the encrypted signal will only operate a pair of liquid crystal glasses having a control circuit adapted to receive the encrypted signal. In an exemplary embodiment, the system further includes a test signal wherein the test signal operates the liquid crystal shutters at a rate that is visible to the user wearing the pair of liquid crystal shutter glasses. 
     A system for providing three dimensional video images has been described that includes a pair of glasses including a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters each having a liquid crystal and an opening time of less than one millisecond, and a control circuit that alternately opens the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter. In an exemplary embodiment, a catch voltage holds the liquid crystal at the point of maximum light transmission. In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. In an exemplary embodiment, the system further includes an emitter that provides a synchronization signal and wherein the synchronization signal causes the control circuit to open one of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the control circuit will only operate after validating the encrypted signal. In an exemplary embodiment, the system further includes a battery sensor. In an exemplary embodiment, the control circuit is adapted to provide an indication of a low battery condition. In an exemplary embodiment, the indication of a low battery condition includes a liquid crystal shutter that is closed for a period of time and then open for a period of time. In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the encrypted signal will only operate a pair of liquid crystal glasses having a control circuit adapted to receive the encrypted signal. In an exemplary embodiment, the system further includes a test signal wherein the test signal operates the liquid crystal shutters at a rate that is visible to a person wearing the pair of liquid crystal shutter glasses. 
     A method for providing a three dimensional video image has been described that includes opening a first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening a second liquid crystal shutter in less than one millisecond, and holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer. In an exemplary embodiment, the method further includes holding the liquid crystal shutter at the point of maximum light transmission by a catch voltage. In an exemplary embodiment, the catch voltage is two volts. In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. In an exemplary embodiment, the method further includes emitting a synchronization signal for controlling an operation of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the synchronization signal will only control the operation of the liquid crystal shutters control circuit after being validating the encrypted signal. In an exemplary embodiment, the method further includes sensing a power level of a battery. In an exemplary embodiment, the method further includes providing an indication of the power level of the battery. In an exemplary embodiment, the indication of a low battery power level includes a liquid crystal shutter that is closed for a period of time and then open for a period of time. In an exemplary embodiment, the method further includes detecting a synchronization signal and then operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the method further includes only operating the liquid crystal shutters after receiving an encrypted signal specially designated for the liquid crystal shutters. In an exemplary embodiment, the method further includes providing a test signal that operates the liquid crystal shutters at a rate that is visible to the viewer. 
     A computer program installed on a machine readable medium in a housing for 3D glasses for providing a three dimensional video image to a user of the 3D glasses has been described that includes causing a liquid crystal to rotate by applying an electrical voltage to the liquid crystal, the liquid crystal achieving a light transmission rate of at least twenty-five percent in less than one millisecond; waiting until the liquid crystal rotates to a point having maximum light transmission; stopping the rotation of the liquid crystal at the point of maximum light transmission; and holding the liquid crystal at the point of maximum light transmission for a period of time. 
     A computer program installed on a machine readable medium for providing a three dimensional video image to a user of the 3D glasses has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, and holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of the user and the second period of time corresponds to the presentation of an image for a second eye of the user. In an exemplary embodiment, the liquid crystal shutter is held at the point of maximum light transmission by a catch voltage. In an exemplary embodiment, the catch voltage is two volts. In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. In an exemplary embodiment, the computer program further includes providing a synchronization signal that controls an operation of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal comprises an encrypted signal. In an exemplary embodiment, the computer program further includes operating the liquid crystal shutters only after validating the encrypted signal. In an exemplary embodiment, the computer program further includes sensing a power level of a battery. In an exemplary embodiment, the computer program includes providing an indication of a low battery condition. In an exemplary embodiment, the computer program further includes providing an indication of a low battery condition by closing a liquid crystal shutter for a period of time and then opening the liquid crystal shutter for a period of time. In an exemplary embodiment, the computer program further includes detecting a synchronization signal and then operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the computer program further includes only operating the liquid crystal shutters after receiving an encrypted signal specifically designated from controlling the liquid crystal shutters. In an exemplary embodiment, the computer program further includes providing a test signal that opens and closes the liquid crystal shutters at a rate that is visible to the user. 
     A system for rapidly opening a liquid crystal shutter has been described that includes means for causing a liquid crystal to rotate by applying an electrical voltage to the liquid crystal, the liquid crystal achieving a light transmission rate of at least twenty-five percent in less than one millisecond; means for waiting until the liquid crystal rotates to a point having maximum light transmission; means for stopping the rotation of the liquid crystal at the point of maximum light transmission; and means for holding the liquid crystal at the point of maximum light transmission for a period of time. 
     A system for providing a three dimensional video image has been described that includes means for opening the first liquid crystal shutter in less than one millisecond, means for holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, means for closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, and means for holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, and wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer. In an exemplary embodiment, at least one of the first and second liquid crystal shutter is held at the point of maximum light transmission by a catch voltage. In an exemplary embodiment, the catch voltage is two volts. In an exemplary embodiment, the point of maximum light transmission transmits more than thirty two percent of light. In an exemplary embodiment, the system further includes means for providing a synchronization signal and wherein the synchronization signal causes one of the liquid crystal shutters to open. In an exemplary embodiment, the synchronization signal comprises an encrypted signal. In an exemplary embodiment, the system further includes means for only operating the liquid crystal shutters after validating the encrypted signal. In an exemplary embodiment, the system further includes means for sensing an operating condition of a battery. In an exemplary embodiment, the system further includes means for providing an indication of a low battery condition. In an exemplary embodiment, the means for providing an indication of a low battery condition includes means for closing a liquid crystal shutter for a period of time and then opening the liquid crystal shutter for a period of time. In an exemplary embodiment, the system further includes means for detecting a synchronization signal and means for operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the system further includes means for only operating the liquid crystal shutters after receiving an encrypted signal specially designated for operating the liquid crystal shutters. In an exemplary embodiment, the system further includes means for operating the liquid crystal shutters at a rate that is visible to the viewer. 
     A method for rapidly opening a liquid crystal shutter for use in 3D glasses has been described that includes causing the liquid crystal to rotate to an open position, waiting until the liquid crystal rotates to a point having maximum light transmission; stopping the rotation of the liquid crystal at the point of maximum light transmission; and holding the liquid crystal at the point of maximum light transmission for a period of time; wherein the liquid crystal comprises an optically thick liquid crystal. 
     A method for providing a three dimensional video image has been described that includes transmitting an encrypted synchronization signal, receiving the encrypted synchronization signal at a remote location, after validating the received encrypted synchronization signal, opening a first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening a second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, providing battery power for opening and closing the liquid crystal shutters; sensing a power level of the battery power, and providing an indication of the sensed power level of the battery power by opening and closing the liquid crystal shutters at a rate that is visible to a viewer, wherein the first period of time corresponds to the presentation of an image for a first eye of the viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, and wherein the liquid crystal shutters are held at the point of maximum light transmission by a catch voltage. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond, a control circuit that alternately opens the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter, and a low battery indicator that includes a battery operably coupled to the control circuit, a sensor capable of determining an amount of power remaining in the battery, a controller adapted to determine whether the amount of power remaining in the battery is sufficient for the pair of glasses to operate longer than a predetermined time, and an indicator to signal a viewer if the glasses will not operate longer than the predetermined time. In an exemplary embodiment, the indicator includes opening and closing the left and right liquid crystal shutters at a predetermined rate. In an exemplary embodiment, the predetermined amount of time is longer than three hours. In an exemplary embodiment, the low battery indicator operates for at least three days after determining the amount of power remaining in the battery is not sufficient for the pair of glasses to operate longer than the predetermined amount of time. In an exemplary embodiment, the controller adapted to determine the amount of power remaining in the battery measures time by a number of synchronization pulses. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, sensing an amount of power remaining in a battery, determining whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time, and indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time. In an exemplary embodiment, indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time includes opening and closing the first and second liquid crystal shutters at a predetermined rate. In an exemplary embodiment, the predetermined amount of time is longer than three hours. In an exemplary embodiment, indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time includes indicating a low-battery signal to a viewer if the three dimensional viewing glasses for at least three days after determining the amount of power remaining in the battery is not sufficient for the pair of three dimensional viewing glasses to operate longer than the predetermined amount of time. In an exemplary embodiment, the method further includes determining the amount of power remaining in the battery comprises measuring a number of synchronization pulses transmitted to the three dimensional viewing glasses. 
     A computer program installed on a machine readable medium for providing a three dimensional video image using a pair of three dimensional viewing glasses including a first liquid crystal shutter and a second liquid crystal shutter has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, sensing an amount of power remaining in a battery, determining whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time, and indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time. In an exemplary embodiment, the computer program includes indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time comprises opening and closing the first and second liquid crystal shutters at a predetermined rate. In an exemplary embodiment, the predetermined amount of time is longer than three hours. In an exemplary embodiment, the computer program includes indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time comprises indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time for at least three days after determining the amount of power remaining in the battery is not sufficient for the pair of three dimensional viewing glasses to operate longer than the predetermined amount of time. In an exemplary embodiment, the computer program further includes determining the amount of power remaining in the battery by measuring a number of synchronization pulses transmitted to the three dimensional viewing glasses. 
     A system for providing a three dimensional video image has been described that includes means for having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, means for opening the first liquid crystal shutter in less than one millisecond, means for holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, means for closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, means for holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, means for sensing an amount of power remaining in a battery, means for determining whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time, and means for indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time. In an exemplary embodiment, the low-battery signal comprises means for opening and closing the first and second liquid crystal shutters at a predetermined rate. In an exemplary embodiment, the predetermined amount of time is longer than three hours. In an exemplary embodiment, the system further includes means for indicating a low battery power for at least three days after determining the amount of power remaining in the battery is not sufficient for the pair of three dimensional viewing glasses to operate longer than the predetermined amount of time. In an exemplary embodiment, the system further includes means for determining the amount of power remaining in the battery by measuring time by a number of synchronization pulses. 
     A system for providing three dimensional video images has been described that includes a pair of three dimensional viewing glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, a control circuit for controlling the operation of the first and second liquid crystal shutters, a battery operably coupled to the control circuit, and a signal sensor operably coupled to the control circuit, wherein the control circuit is adapted to determine whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time as a function of a number of external signals detected by the signal sensor and operate the first and second liquid crystal shutters to provide a visual indication of the amount of power remaining in the battery. In an exemplary embodiment, the visual indication comprises opening and closing the first and second liquid crystal shutters at a predetermined rate. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, sensing an amount of power remaining in a battery by determining a number of external signals transmitted to the three dimensional viewing glasses, determining whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time, and indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time. In an exemplary embodiment, the low-battery signal includes opening and closing the first and second liquid crystal shutters at a predetermined rate. 
     A computer program stored in a memory device for use in operating a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter providing a three dimensional video image has been described that includes sensing an amount of power remaining in a battery of the three dimensional viewing glasses by determining a number of external signals transmitted to the three dimensional viewing glasses, determining whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time, and indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time. In an exemplary embodiment, the low-battery signal comprises opening and closing the first and second liquid crystal shutters at a predetermined rate. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses including a first liquid crystal shutter and a second liquid crystal shutter has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, sensing an amount of power remaining in a battery, determining whether the amount of power remaining in the battery is sufficient for the pair of three dimensional viewing glasses to operate longer than a predetermined time, and indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time; wherein indicating a low-battery signal to a viewer if the three dimensional viewing glasses will not operate longer than the predetermined time includes opening and closing the first and second liquid crystal shutters at a predetermined rate, and wherein determining the amount of power remaining in the battery comprises measuring a number of synchronization pulses transmitted to the three dimensional viewing glasses. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters each having a liquid crystal and an opening time of less than one millisecond, a control circuit that alternately opens the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter, and a synchronization device operably coupled to the control circuit, including a signal receiver for sensing a synchronization signal corresponding to an image presented to a user of the glasses, and a control circuit adapted to open the first liquid crystal shutter or the second liquid crystal shutter during a period of time in which the image is presented as a function of the synchronization signal transmitted. In an exemplary embodiment, the synchronization signal includes an infrared light. In an exemplary embodiment, the system further includes a signal transmitter, wherein the signal transmitter projects the synchronization signal toward a reflector, wherein the synchronization signal is reflected by the reflector, and wherein the signal receiver detects the reflected synchronization signal. In an exemplary embodiment, the reflector comprises a movie theater screen. In an exemplary embodiment, the signal transmitter receives a timing signal from an image projector. In an exemplary embodiment, the synchronization signal includes a radio frequency signal. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval, wherein a first predetermined number of pulses opens the first liquid crystal shutter, and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, the synchronization signal is encrypted. In an exemplary embodiment, the synchronization signal comprises a series of pulses and configuration data for the control circuit. In an exemplary embodiment, at least one of the series of pulses and the configuration data are encrypted. In an exemplary embodiment, the synchronization signal includes at least one data bit preceded by at least one clock pulse. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. In an exemplary embodiment, the synchronization signal is sensed between the presentation of images for the first and second liquid crystal shutters. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, transmitting a synchronization signal corresponding to the image presented to the viewer, sensing the synchronization signal, and using the synchronization signal to determine when to open the first liquid crystal shutter or the second liquid crystal shutter. In an exemplary embodiment, the synchronization signal includes an infrared light. In an exemplary embodiment, the method further includes projecting the synchronization signal toward a reflector, reflecting the synchronization signal off of the reflector, and detecting the reflected synchronization signal. In an exemplary embodiment, the method further includes reflecting the synchronization signal off of a movie theater screen. In an exemplary embodiment, the method further includes receiving a timing signal from an image projector. In an exemplary embodiment, the synchronization signal includes a radio frequency signal. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval, wherein a first predetermined number of pulses opens the first liquid crystal shutter, and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, the method further includes encrypting the synchronization signal. In an exemplary embodiment, the synchronization signal includes a series of pulses and configuration data for the control circuit. In an exemplary embodiment, the method further includes encrypting at least one of the series of pulses and the configuration data. In an exemplary embodiment, the synchronization signal includes at least one data bit preceded by at least one clock pulse. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. In an exemplary embodiment, the synchronization signal is sensed between the presentation of images for the first and second liquid crystal shutters. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond, a control circuit that alternately opens the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter, and a synchronization system including: a reflection device located in front of the pair of glasses, a signal transmitter sending a synchronization signal towards the reflection device, the synchronization signal corresponding to an image presented to a user of the glasses, a signal receiver sensing the synchronization signal reflected from the reflection device, and a control circuit adapted to open the first shutter or the second shutter during a period of time in which the image is presented. In an exemplary embodiment, the synchronization signal includes an infrared light. In an exemplary embodiment, the reflector includes a movie theater screen. In an exemplary embodiment, the signal transmitter receives a timing signal from an image projector. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval, wherein a first predetermined number of pulses opens the first liquid crystal shutter, and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, the synchronization signal is encrypted. In an exemplary embodiment, the synchronization signal includes a series of pulses and configuration data for the control circuit. In an exemplary embodiment, at least one of the series of pulses and the configuration data are encrypted. In an exemplary embodiment, the synchronization signal includes at least one data bit preceded by at least one clock pulse. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. In an exemplary embodiment, the synchronization signal is sensed between the presentation of images for the first and second liquid crystal shutters. 
     A computer program installed on a machine readable medium for providing a three dimensional video image, using a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, sensing a synchronization signal corresponding to an image presented to the viewer, and using the sensed synchronization signal to determine when to open the first or the second liquid crystal shutter. In an exemplary embodiment, the synchronization signal includes an infrared light. In an exemplary embodiment, the computer program further includes projecting the synchronization signal toward a reflector, reflecting the synchronization signal off of the reflector, and detecting the reflected synchronization signal. In an exemplary embodiment, the reflector includes a movie theater screen. In an exemplary embodiment, the computer program further includes receiving a timing signal from an image projector. In an exemplary embodiment, the synchronization signal includes a radio frequency signal. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval, wherein a first predetermined number of pulses opens the first liquid crystal shutter, and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, the computer program further includes encrypting the synchronization signal. In an exemplary embodiment, the synchronization signal includes a series of pulses and configuration data for the control circuit. In an exemplary embodiment, the computer program further includes encrypting at least one of the series of pulses and the configuration data. In an exemplary embodiment, the synchronization signal includes at least one data bit preceded by at least one clock pulse. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. In an exemplary embodiment, the computer program further includes sensing the synchronization signal between the presentation of images for the first and second liquid crystal shutters. 
     A system for providing a three dimensional video image has been described that includes means for having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, means for opening the first liquid crystal shutter in less than one millisecond, means for holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, means for closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, means for holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, means for sensing a synchronization signal corresponding to the image presented to the viewer, and means for using the sensed synchronization signal to determine when to open the first or the second liquid crystal shutter. In an exemplary embodiment, the synchronization signal includes an infrared light. In an exemplary embodiment, the system further includes means for transmitting the synchronization signal toward a reflector. In an exemplary embodiment, the reflector includes a movie theater screen. In an exemplary embodiment, the means for transmitting includes means for receiving a timing signal from an image projector. In an exemplary embodiment, the synchronization signal includes a radio frequency signal. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval and wherein a first predetermined number of pulses opens the first liquid crystal shutter and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, the system further includes means for encrypting the synchronization signal. In an exemplary embodiment, the synchronization signal includes a series of pulses and configuration data for the control circuit. In an exemplary embodiment, the system further includes means for encrypting at least one of the series of pulses and the configuration data. In an exemplary embodiment, the synchronization signal includes at least one data bit preceded by at least one clock pulse. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. In an exemplary embodiment, the system further includes means for sensing the synchronization signal between the presentation of images for the first and second liquid crystal shutters. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of the viewer, projecting an encrypted synchronization signal toward a reflector, reflecting the encrypted synchronization signal off of the reflector, detecting the reflected encrypted synchronization signal, decrypting the detected encrypted synchronization signal, and using the detected synchronization signal to determine when to open the first liquid crystal shutter or the second liquid crystal shutter, wherein the synchronization signal comprises an infrared light, wherein the synchronization signal comprises a series of pulses and configuration data, wherein a first predetermined series of pulses opens the first liquid crystal shutter, wherein a second predetermined series of pulses opens the second liquid crystal shutter, wherein the synchronization signal comprises at least one data bit preceded by at least one clock pulse, wherein the synchronization signal comprise a synchronous serial data signal, and wherein the synchronization signal is detected between the presentation of images for the first and second liquid crystal shutters. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond, a control circuit that alternately opens the first and second liquid crystal shutters, and wherein an orientation of at least one of the liquid crystal shutters is held at a point of maximum light transmission until the control circuit closes the liquid crystal shutter, and a test system comprising a signal transmitter, a signal receiver, and a test system control circuit adapted to open and close the first and second liquid crystal shutters at a rate that is visible to a viewer. In an exemplary embodiment, the signal transmitter does not receive a timing signal from a projector. In an exemplary embodiment, the signal transmitter emits an infrared signal. In an exemplary embodiment, the infrared signal comprises a series of pulses. In an exemplary embodiment, the signal transmitter emits an radio frequency signal. In an exemplary embodiment, the radio frequency signal comprises a series of pulses. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, transmitting a test signal towards the three dimensional viewing glasses, receiving the test signal with a sensor on the three dimensional glasses, and using a control circuit to open and close the first and second liquid crystal shutters as a result of the received test signal, wherein the liquid crystal shutters open and close at a rate that is observable to a viewer wearing the glasses. In an exemplary embodiment, the signal transmitter does not receive a timing signal from a projector. In an exemplary embodiment, the signal transmitter emits an infrared signal. In an exemplary embodiment, the infrared signal comprises a series of pulses. In an exemplary embodiment, the signal transmitter emits an radio frequency signal. In an exemplary embodiment, the radio frequency signal includes a series of pulses. 
     A computer program installed on a machine readable medium for providing a three dimensional video image using a pair of three dimensional viewing glasses including a first liquid crystal shutter and a second liquid crystal shutter, the computer program has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, transmitting a test signal towards the three dimensional viewing glasses, receiving the test signal with a sensor on the three dimensional glasses, and using a control circuit to open and close the first and second liquid crystal shutters as a result of the received test signal, wherein the liquid crystal shutters open and close at a rate that is observable to a viewer wearing the glasses. In an exemplary embodiment, the signal transmitter does not receive a timing signal from a projector. In an exemplary embodiment, the signal transmitter emits an infrared signal. In an exemplary embodiment, the infrared signal includes a series of pulses. In an exemplary embodiment, the signal transmitter emits an radio frequency signal. In an exemplary embodiment, the radio frequency signal comprises a series of pulses. 
     A system for providing a three dimensional video image has been described that includes a means for having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, means for opening the first liquid crystal shutter in less than one millisecond, means for holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, means for closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, means for holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, means for transmitting a test signal towards the three dimensional viewing glasses, means for receiving the test signal with a sensor on the three dimensional glasses, and means for using a control circuit to open and close the first and second liquid crystal shutters as a result of the test signal, wherein the liquid crystal shutters open and close at a rate that is observable to a viewer wearing the glasses. In an exemplary embodiment, the means for transmitting does not receive a timing signal from a projector. In an exemplary embodiment, the means for transmitting emits an infrared signal. In an exemplary embodiment, the infrared signal includes a series of pulses. In an exemplary embodiment, the means for transmitting emits an radio frequency signal. In an exemplary embodiment, the radio frequency signal includes a series of pulses. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, transmitting an infrared test signal towards the three dimensional viewing glasses, receiving the infrared test signal with a sensor on the three dimensional glasses, and using a control circuit to open and close the first and second liquid crystal shutters as a result of the received infrared test signal, wherein the liquid crystal shutters open and close at a rate that is observable to a viewer wearing the glasses, wherein the signal transmitter does not receive a timing signal from a projector, wherein the infrared signal comprises a series of pulses, wherein the infrared signal comprises one or more data bits that are each preceded by at least one clock pulse, and wherein the infrared signal comprises a synchronous serial data signal. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters each having a liquid crystal and an opening time of less than one millisecond, a control circuit that alternately opens the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter, and signal receiver operably coupled to the control circuit, wherein the control circuit is adapted to activate the signal receiver at a first predetermined time interval, determine if the signal receiver is receiving a valid signal, deactivate the signal receiver if the signal receiver does not receive the valid signal within a second predetermined time interval, and alternately open and close the first and second shutters at an interval corresponding to the valid signal if the signal receiver does receive the valid signal. In an exemplary embodiment, the first period of time includes at least two seconds. In an exemplary embodiment, the second period of time includes no more than 100 milliseconds. In an exemplary embodiment, both of the liquid crystal shutters remain either open or closed until the signal receiver receives the valid signal. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, activating a signal receiver at a first predetermined time interval, determining if the signal receiver is receiving a valid signal from a signal transmitter, deactivating the signal receiver if the signal receiver does not receive the valid signal from the signal transmitter within a second period of time, and opening and closing the first and second shutters at an interval corresponding to the valid signal if the signal receiver does receive the valid signal from the signal transmitter. In an exemplary embodiment, the first period of time includes at least two seconds. In an exemplary embodiment, the second period of time includes no more than 100 milliseconds. In an exemplary embodiment, both of the liquid crystal shutters remain either open or closed until the signal receiver receives a valid signal from the signal transmitter. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond, a control circuit that can alternately open the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter, and wherein the control circuit is adapted to hold both the first liquid crystal shutter and the second liquid crystal shutter open. In an exemplary embodiment, the control circuit holds the first liquid crystal shutter and the second liquid crystal shutter open until the control circuit detects a synchronization signal. In an exemplary embodiment, a voltage applied to the first and second liquid crystal shutters alternates between positive and negative. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, wherein the first liquid crystal shutter can open in less than one millisecond, wherein the second liquid crystal shutter can open in less than one millisecond, and opening and closing the first and second liquid crystal shutters at a rate that makes the first and, second liquid crystal shutters appear to be clear lenses to a user. In an exemplary embodiment, the method further includes opening and closing the first and second liquid crystal shutters at a rate that makes the liquid crystal shutters appear to be clear lenses to the user until detecting a valid synchronization signal. In an exemplary embodiment, the method further includes applying a voltage to the first and second liquid crystal shutters that alternates between positive and negative until detecting a valid synchronization signal. 
     A computer program installed on a machine readable medium for providing a three dimensional video image, for use in a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, activating a signal receiver at a first predetermined time interval, determining if the signal receiver is receiving a valid signal from the signal transmitter, deactivating the signal receiver if the signal receiver does not receive the valid signal from the signal transmitter within a second period of time, and opening and closing the first and second shutters at an interval corresponding to the valid signal if the signal receiver does receive the valid signal from the signal transmitter. In an exemplary embodiment, the first period of time comprises at least two seconds. In an exemplary embodiment, the second period of time comprises no more than 100 milliseconds. In an exemplary embodiment, the first and second liquid crystal shutters remain open until the signal receiver receives the valid signal from the signal transmitter. 
     A computer program installed on a machine readable medium for providing a three dimensional video image, for use in a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, wherein the first liquid crystal shutter can open in less than one millisecond, and wherein the second liquid crystal shutter can open in less than one millisecond, and has been described that includes opening and closing the first and second liquid crystal shutters at a rate that makes the liquid crystal shutters appear to be clear lenses. In an exemplary embodiment, the computer program further includes holding the first and second liquid crystal shutters open until detecting a valid synchronization signal. In an exemplary embodiment, the computer program further includes applying a voltage to the first and second liquid crystal shutters that alternates between positive and negative until detecting a valid synchronization signal. 
     A system for providing a three dimensional video image has been described that includes means for providing a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, means for opening the first liquid crystal shutter in less than one millisecond, means for holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, means for closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, means for holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, means for activating a signal receiver at a first predetermined time interval, means for determining if the signal receiver is receiving a valid signal from the signal transmitter, means for deactivating the signal receiver if the signal receiver does not receive the valid signal from the signal transmitter within a second period of time, and means for opening and closing the first and second shutters at an interval corresponding to the valid signal if the signal receiver does receive the valid signal from the signal transmitter. In an exemplary embodiment, the first period of time includes at least two seconds. In an exemplary embodiment, the second period of time includes no more than 100 milliseconds. In an exemplary embodiment, the first and second liquid crystal shutters remain open until the signal receiver receives a valid signal from the signal transmitter. 
     A system for providing three dimensional video images has been described that includes a pair of glasses including a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters having a liquid crystal and an opening time of less than one millisecond, and a control circuit that alternately opens the first and second liquid crystal shutters, wherein the liquid crystal orientation is held at a point of maximum light transmission until the control circuit closes the shutter, wherein the control circuit opens and closes the first and second liquid crystal shutters after the glasses are powered on for a predetermined time period. In an exemplary embodiment, the control circuit alternatively opens and closes the first and second liquid crystal shutters after the glasses are powered on for a predetermined time period. In an exemplary embodiment, the control circuit, after the predetermined time period, then opens and closes the first and second liquid crystal shutters as a function of a synchronization signal received by the control circuit. In an exemplary embodiment, the synchronization signal comprises a series of pulses at a predetermined interval. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval and wherein a first predetermined number of pulses opens the first liquid crystal shutter and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, a portion of the series of pulses is encrypted. In an exemplary embodiment, the series of pulses includes a predetermined number of pulses that are not encrypted followed by encrypted data. In an exemplary embodiment, the synchronization signal comprises one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. 
     A method for providing a three dimensional video image has been described that includes having a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, powering on the glasses; and opening and closing the first and second liquid crystal shutters for a predetermined time period after powering on the glasses. In an exemplary embodiment, the method further includes providing a synchronization signal, wherein a portion of the synchronization signal is encrypted, sensing the synchronization signal, and wherein the first and second liquid crystal shutters open and close in a pattern corresponding to the sensed synchronization signal only after receiving an encrypted signal after the predetermined time period. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval and wherein a first predetermined number of pulses opens the first liquid crystal shutter and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, a portion of the series of pulses is encrypted. In an exemplary embodiment, the series of pulses includes a predetermined number of pulses that are not encrypted followed by a predetermined number of pulses that are encrypted. In an exemplary embodiment, the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving two consecutive encrypted signals. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal comprises a synchronous serial data signal. 
     A computer program installed on a machine readable medium for providing a three dimensional video image, using a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, has been described that includes opening the first liquid crystal shutter in less than one millisecond, holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, powering on the glasses; and opening and closing the first and second liquid crystal shutters for a predetermined time period after powering on the glasses. In an exemplary embodiment, the computer program further includes providing a synchronization signal, wherein a portion of the synchronization signal is encrypted, sensing the synchronization signal, and wherein the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving an encrypted signal after the predetermined time period. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval, and wherein a first predetermined number of pulses opens the first liquid crystal shutter and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, a portion of the series of pulses is encrypted. In an exemplary embodiment, the series of pulses includes a predetermined number of pulses that are not encrypted followed by a predetermined number of pulses that are encrypted. In an exemplary embodiment, the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving two consecutive encrypted signals. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal comprises a synchronous serial data signal. 
     A system for providing a three dimensional video image has been described that includes means for providing a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, wherein the first liquid crystal shutter can open in less than one millisecond, wherein the second liquid crystal shutter can open in less than one millisecond, and means for opening and closing the first and second liquid crystal shutters after powering up the glasses for a predetermined period of time. In an exemplary embodiment, the system further includes means for opening and closing the first and second liquid crystal shutters upon receiving a synchronization signal after the predetermined period of time. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. 
     A system for providing a three dimensional video image has been described that includes means for providing a pair of three dimensional viewing glasses comprising a first liquid crystal shutter and a second liquid crystal shutter, means for opening the first liquid crystal shutter in less than one millisecond, means for holding the first liquid crystal shutter at a point of maximum light transmission for a first period of time, means for closing the first liquid crystal shutter and then opening the second liquid crystal shutter in less than one millisecond, means for holding the second liquid crystal shutter at a point of maximum light transmission for a second period of time, wherein the first period of time corresponds to the presentation of an image for a first eye of a viewer and the second period of time corresponds to the presentation of an image for a second eye of a viewer, and means for opening and closing the first and second liquid crystal shutters after powering up the glasses for a predetermined period of time. In an exemplary embodiment, the system further includes means for transmitting a synchronization signal, wherein a portion of the synchronization signal is encrypted, means for sensing the synchronization signal, and means for opening and closing the first and second liquid crystal shutters in a pattern corresponding to the synchronization signal only after receiving an encrypted signal after the predetermined time period. In an exemplary embodiment, the synchronization signal includes a series of pulses at a predetermined interval and wherein a first predetermined number of pulses opens the first liquid crystal shutter and wherein a second predetermined number of pulses opens the second liquid crystal shutter. In an exemplary embodiment, a portion of the series of pulses is encrypted. In an exemplary embodiment, the series of pulses includes a predetermined number of pulses that are not encrypted followed by a predetermined number of pulses that are encrypted. In an exemplary embodiment, the first and second liquid crystal shutters open and close in a pattern corresponding to the synchronization signal only after receiving two consecutive encrypted signals. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal comprises a synchronous serial data signal. 
     A frame for 3-D glasses having right and left viewing shutters has been described that includes a frame front that defines right and left lens openings for receiving the right and left viewing shutters; and right and left temples coupled to and extending from the frame front for mounting on a head of a user of the 3-D glasses; wherein each of the right and left temples comprise a serpentine shape. In an exemplary embodiment, each of the right and left temples include one or more ridges. In an exemplary embodiment, the frame further includes a left shutter controller mounted within the frame for controlling the operation of the left viewing shutter; a right shutter controller mounted within the frame for controlling the operation of the right viewing shutter; a central controller mounted within the frame for controlling the operation of the left and right shutter controllers; a signal sensor operably coupled to the central controller for sensing a signal from an external source; and a battery mounted within the frame operably coupled to the left and right shutter controllers, the central controller, and the signal sensor for supplying power to the left and right shutter controllers, the central controller, and the signal sensor. In an exemplary embodiment, the viewing shutters each include a liquid crystal having an opening time of less than one millisecond. In an exemplary embodiment, the frame further includes a battery sensor operably coupled to the battery and the central controller for monitoring the operating status of the battery and providing a signal to the central controller representative of the operating status of the battery. In an exemplary embodiment, the frame further includes a charge pump operably coupled to the battery and the central controller for providing an increased voltage supply to the left and right shutter controllers. In an exemplary embodiment, the frame further includes a common shutter controller operably coupled to the central controller for controlling the operation of the left and right shutter controllers. In an exemplary embodiment, the signal sensor includes a narrow band pass filter; and a decoder. 
     3-D glasses having right and left viewing shutters have been described that include a frame defining left and right lens openings for receiving the right and left viewing shutters; a central controller for controlling the operation of the right and left viewing shutters; a housing coupled to the frame for housing the central controller defining an opening for accessing at least a portion of the controller; and a cover received within and sealingly engaging the opening in the housing. In an exemplary embodiment, the cover comprises an o-ring seal for sealingly engaging the opening in the housing. In an exemplary embodiment, the cover comprises one or more keying members for engaging complimentary recesses formed in the opening in the housing. In an exemplary embodiment, the 3-D glasses further include a left shutter controller operably coupled to the central controller mounted within the housing for controlling the operation of the left viewing shutter; a right shutter controller operably coupled to the central controller mounted within the housing for controlling the operation of the right viewing shutter; a signal sensor operably coupled to the central controller for sensing a signal from an external source; and a battery mounted within the housing operably coupled to the left and right shutter controllers, the central controller, and the signal sensor for supplying power to the left and right shutter controllers, the central controller, and the signal sensor. In an exemplary embodiment, the viewing shutters each include a liquid crystal having an opening time of less than one millisecond. In an exemplary embodiment, the 3-D glasses further include a battery sensor operably coupled to the battery and the central controller for monitoring the operating status of the battery and providing a signal to the central controller representative of the operating status of the battery. In an exemplary embodiment, the 3-D glasses further include a charge pump operably coupled to the battery and the central controller for providing an increased voltage supply to the left and right shutter controllers. In an exemplary embodiment, the 3-D glasses further include a common shutter controller operably coupled to the central controller for controlling the operation of the left and right shutter controllers. In an exemplary embodiment, the signal sensor includes a narrow band pass filter; and a decoder. 
     A method of housing a controller for 3-D glasses having right and left viewing elements has been described that includes providing a frame for supporting the right and left viewing elements for wearing by a user; providing a housing within the frame for housing a controller for the 3-D glasses; and sealing the housing within the frame using a removable cover having a sealing element for sealingly engaging the housing. In an exemplary embodiment, the cover includes one or more dimples. In an exemplary embodiment, sealing the housing comprises operating a key to engage the dimples in the cover of the housing. In an exemplary embodiment, the housing further houses a removable battery for providing power to the controller for the 3-D glasses. 
     A system for providing a three dimensional video image to a user of 3D glasses has been described that includes a power supply, first and a second liquid crystal shutters operably coupled to the power supply, and a control circuit operably coupled to the power supply and the liquid crystal shutters adapted to open the first liquid crystal shutter for a first period of time, close the first liquid crystal shutter for a second period of time, open the second liquid crystal shutter for the second period of time, close the second liquid crystal shutter for the first period of time, and transfer charge between the first and second liquid crystal shutters during portions of at least one of the first and second periods of time, wherein the first period of time corresponds to the presentation of an image for a first eye of the user and the second period of time corresponds to the presentation of an image for a second eye of the user. In an exemplary embodiment, the control circuit is adapted to use a synchronization signal to determine the first and second periods of time. In an exemplary embodiment, the system further includes an emitter that provides a synchronization signal and wherein the synchronization signal causes the control circuit to open one of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the control circuit will only operate after validating the encrypted signal. In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the encrypted signal will only operate a pair of liquid crystal glasses having a control circuit adapted to receive the encrypted signal. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal comprises a synchronous serial data signal. 
     A system for providing three dimensional video images has been described that includes a pair of glasses comprising a first lens having a first liquid crystal shutter and a second lens having a second liquid crystal shutter, the liquid crystal shutters each having a liquid crystal, and a control circuit that alternately opens the first and second liquid crystal shutters and transfers charge between the liquid crystal shutters. In an exemplary embodiment, the system further includes an emitter that provides a synchronization signal and wherein the synchronization signal causes the control circuit to open one of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the control circuit will only operate after validating the encrypted signal. In an exemplary embodiment, the control circuit is adapted to detect a synchronization signal and begin operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the encrypted signal will only operate a pair of liquid crystal glasses having a control circuit adapted to receive the encrypted signal. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. 
     A method for providing a three dimensional video image using first and second liquid crystal shutters has been described that includes closing the first liquid crystal shutter and opening the second liquid crystal shutter, then closing the second liquid crystal shutter and opening the first liquid crystal shutter, and transferring charge between the first and second liquid crystal shutters. In an exemplary embodiment, the method further includes providing a synchronization signal, and opening one of the liquid crystal shutters in response to the synchronization signal. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the method further includes operating only after validating the encrypted signal. In an exemplary embodiment, the method further includes detecting a synchronization signal, and begin operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the synchronization signal comprises one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. 
     A computer program installed on a machine readable medium in a housing for 3D glasses having first and second liquid crystal shutters for providing a three dimensional video image to a user of the 3D glasses has been described that includes closing the first liquid crystal shutter and opening the second liquid crystal shutter, then closing the second liquid crystal shutter and opening the first liquid crystal shutter, and transferring charge between the first and second liquid crystal shutters. In an exemplary embodiment, the computer program further includes providing a synchronization signal, and opening one of the liquid crystal shutters in response to the synchronization signal. In an exemplary embodiment, the synchronization signal includes an encrypted signal. In an exemplary embodiment, the computer program further includes validating the encrypted signal. In an exemplary embodiment, the computer program further includes detecting a synchronization signal, and operating the liquid crystal shutters after detecting the synchronization signal. In an exemplary embodiment, the synchronization signal comprises one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. 
     A system for providing a three dimensional video image using first and second liquid crystal shutters has been described that includes means for closing the first liquid crystal shutter and opening the second liquid crystal shutter, means for then closing the second liquid crystal shutter and opening the first liquid crystal shutter, and means for transferring charge between the first and second liquid crystal shutters. In an exemplary embodiment, the system further includes means for providing a synchronization signal, and means for the synchronization signal causing opening one of the liquid crystal shutters. In an exemplary embodiment, the synchronization signal comprises an encrypted signal. In an exemplary embodiment, the system further includes means for only operating after validating the encrypted signal. In an exemplary embodiment, the synchronization signal includes one or more data bits that are each preceded by one or more clock pulses. In an exemplary embodiment, the synchronization signal includes a synchronous serial data signal. In an exemplary embodiment, the system further includes means for detecting a synchronization signal, and means for operating the liquid crystal shutters after detecting the synchronization signal. 
     A system for providing electrical power to 3D glasses including left and right liquid crystal shutters has been described that includes a controller operably coupled to the left and right liquid crystal shutters; a battery operably coupled to the controller; and a charge pump operably coupled to the controller; wherein the controller is adapted to transfer electrical charge between the left and right liquid crystal shutters when changing the operational state of either of the left or right liquid crystal shutter; and wherein the charge pump is adapted to accumulate electrical potential when the controller changes the operational state of either the left or right liquid crystal shutter. In an exemplary embodiment, the charge pump is adapted to stop accumulating electrical potential when the level of the electrical potential equals a predetermined level. 
     A method of providing electrical power to 3D glasses including left and right liquid crystal shutters has been described that includes transferring electrical charge between the left and right liquid crystal shutters when changing the operational state of either of the left or right liquid crystal shutters; and accumulating electrical potential when changing the operational state of either the left or right liquid crystal shutters. In an exemplary embodiment, the method further includes stopping the accumulation of electrical potential when the level of the electrical potential equals a predetermined level. 
     A computer program stored in a machine readable medium for providing electrical power to 3D glasses including left and right liquid crystal shutters has been described that includes transferring electrical charge between the left and right liquid crystal shutters when changing the operational state of either of the left or right liquid crystal shutters; and accumulating electrical potential when changing the operational state of either the left or right liquid crystal shutters. In an exemplary embodiment, the computer program further includes stopping the accumulation of electrical potential when the level of the electrical potential equals a predetermined level. 
     A system for providing electrical power to 3D glasses including left and right liquid crystal shutters has been described that includes means for transferring electrical charge between the left and right liquid crystal shutters when changing the operational state of either of the left or right liquid crystal shutters; and means for accumulating electrical potential when changing the operational state of either the left or right liquid crystal shutters. In an exemplary embodiment, the system further includes means for stopping the accumulation of electrical potential when the level of the electrical potential equals a predetermined level. 
     A signal sensor for use in 3D glasses for receiving a signal from a signal transmitter and sending a decoded signal to a controller for operating the 3D glasses has been described that includes a band pass filter for filtering the signal received from the signal transmitter; and a decoder operably coupled to the band pass filter for decoding the filtered signal and providing the decoded signal to the controller of the 3D glasses. In an exemplary embodiment, the signal received from the signal transmitter includes one or more data bits; and one or more clock pulses that precede a corresponding one of the data bits. In an exemplary embodiment, the signal received from the signal transmitter comprises a synchronous serial data transmission. In an exemplary embodiment, the signal received from the signal transmitter comprise a synchronization signal for controlling the operation of the 3D glasses. 
     3-D have been described that include a band pass filter for filtering the signal received from a signal transmitter; a decoder operably coupled to the band pass filter for decoding the filtered signal; a controller operably coupled to the decoder for receiving the decoded signal; and left and right optical shutters operably coupled to and controlled by the controller as a function of the decoded signal. In an exemplary embodiment, the signal received from the signal transmitter includes one or more data bits; and one or more clock pulses that proceed a corresponding one of the data bits. In an exemplary embodiment, the signal received from the signal transmitter comprises a synchronous serial data transmission. 
     A method of transmitting data signals to 3D glasses has been described that includes transmitting a synchronous serial data signal to the 3D glasses. In an exemplary embodiment, the data signal comprises one or more data bits that are each preceded by a corresponding clock pulse. In an exemplary embodiment, the method further includes filtering the data signal to remove out of band noise. In an exemplary embodiment, the synchronous serial data signal comprises a synchronization signal for controlling the operation of the 3D glasses. 
     A method of operating 3D glasses having left and right optical shutters has been described that includes transmitting a synchronous serial data signal to the 3D glasses; and controlling the operation of the left and right optical shutters as a function of data encoded in the data signal. In an exemplary embodiment, the data signal includes one or more data bits that are each preceded by a corresponding clock pulse. In an exemplary embodiment, the method further includes filtering the data signal to remove out of band noise. 
     A computer program for transmitting data signals to 3D glasses has been described that includes transmitting a synchronous serial data signal to the 3D glasses. In an exemplary embodiment, the data signal includes one or more data bits that are each preceded by a corresponding clock pulse. In an exemplary embodiment, the computer program further includes filtering the data signal to remove out of band noise. In an exemplary embodiment, the synchronous serial data signal includes a synchronization signal for controlling the operation of the 3D glasses. 
     A computer program for operating 3D glasses having left and right optical shutters has been described that includes transmitting a synchronous serial data signal to the 3D glasses; and controlling the operation of the left and right optical shutters as a function of data encoded in the data signal. In an exemplary embodiment, the data signal includes one or more data bits that are each preceded by a corresponding clock pulse. In an exemplary embodiment, the computer program further includes filtering the data signal to remove out of band noise. 
     A synchronization signal for operating one or more optical shutters within a pair of three dimensional viewing glasses, the synchronization signal stored within a machine readable medium, has been described that includes one or more data bits for controlling the operation of the one or more of the optical shutters within the pair of three dimensional viewing glasses; and one or more clock pulses that precede each of the data bits. In an exemplary embodiment, the signal is stored within a machine readable medium operably coupled to a transmitter. In an exemplary embodiment, the transmitter includes an infra red transmitter. In an exemplary embodiment, the transmitter includes a visible light transmitter. In an exemplary embodiment, the transmitter includes a radio frequency transmitter. In an exemplary embodiment, the signal is stored within a machine readable medium operably coupled to a receiver. In an exemplary embodiment, the transmitter includes an infra red transmitter. In an exemplary embodiment, the transmitter includes a visible light transmitter. In an exemplary embodiment, the transmitter includes a radio frequency transmitter. 
     A method of synchronizing the operation of 3D glasses having left and right shutters with a display device has been described that includes initially synchronizing the operation of the 3D glasses with the operation of the display device; and periodically resynchronizing the operation of the 3D glasses with the operation of the display device. In an exemplary embodiment, initially synchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises one or more synchronization pulses. In an exemplary embodiment, initially synchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises information representative of the type of the display device. In an exemplary embodiment, initially synchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises information representative of an opening and closing sequence of the left and right shutters. In an exemplary embodiment, initially synchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises information representative of an operating frequency of the images displayed on the display device. In an exemplary embodiment, initially synchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises one or more synchronization pulses; transmitting a signal from the display device to the 3D glasses that comprises information representative of the type of the display device; transmitting a signal from the display device to the 3D glasses that comprises information representative of an opening and closing sequence of the left and right shutters; and transmitting a signal from the display device to the 3D glasses that comprises information representative of an operating frequency of the images displayed on the display device. In an exemplary embodiment, periodically resynchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises one or more synchronization pulses. In an exemplary embodiment, periodically resynchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises information representative of a time of transmission of the signal. In an exemplary embodiment, periodically resynchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises information representative of a time delay of the transmission of the signal. In an exemplary embodiment, periodically resynchronizing the operation of the 3D glasses with the operation of the display device comprises transmitting a signal from the display device to the 3D glasses that comprises one or more synchronization pulses; transmitting a signal from the display device to the 3D glasses that comprises information representative of a time of transmission of the signal; and transmitting a signal from the display device to the 3D glasses that comprises information representative of a time delay of the transmission of the signal. In an exemplary embodiment, the method further includes the 3D glasses using the time delay of the transmission of the signal to resynchronize the operation of the 3D glasses with the operation of the display device. 
     It is understood that variations may be made in the above without departing from the scope of the invention. While specific embodiments have been shown and described, modifications can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments as described are exemplary only and are not limiting. Many variations and modifications are possible and are within the scope of the invention. Furthermore, one or more elements of the exemplary embodiments may be omitted, combined with, or substituted for, in whole or in part, one or more elements of one or more of the other exemplary embodiments. Accordingly, the scope of protection is not limited to the embodiments described, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.