Abstract:
A liquid crystal display (LCD) has an electro-mechanical structure over the surface of the display that enables the light from individual picture elements (pixels) to be directed by X and Y control signals. The electro-mechanical structure provides individual prism/lense elements over each pixel. The prism/lense element is configured so that light from the LCD may be directed towards each eye of a viewer. The prism/lense elements have a piezoelectric material integrated on a beam supporting the prism/lense element which may be energized with control signals to alter the angle of the prism/lense element so that the light may be selectively directed towards each eye of the viewer. Each piezoelectric element (PZE) has a positive and negative voltage terminal. One of the voltage terminals is “addressed” with an X line and the other with a Y line creating a matrix selection of each PZE. The voltage level of the X line may be varied to add further control of the PZE. If an X voltage is present and the corresponding Y return line is selected, then a PZE will deflect the particular prism/lense element. By alternatively presenting an image frame for each of the viewer&#39;s eyes and correspondingly controlling the pixels, a 3D image is perceived by the viewer. Adjustment is provided so that the level of the X voltages may be controlled by a viewer to personally optimize the display. Algorithms may be employed to control when particular pixels are activated and by how much so that anomalies in the display may be controlled.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates in general to an apparatus and methods for producing a viewable stereoscopic image from a two-dimensional display.  
         BACKGROUND INFORMATION  
         [0002]    When correctly implemented, stereoscopic three dimensional (3D) video displays may provide significant benefits in many application areas, including endoscopy and other medical imaging, remote-control vehicles and tele-manipulators, stereo 3D Computer Aided Design (CAD), molecular modeling, 3D computer graphics, 3D visualization, video-based training and entertainment.  
           [0003]    Stereoscopic displays usually require the use of cumbersome glasses or other types of viewers. The display presents an image for the right eye and an alternate image for the left eye. A variety of viewing units, which correspond to the type of image displayed, are used to “fool” the brain into thinking it is observing a true 3D object. Some glasses are polarized and are used with corresponding polarized images. Polarization, while effective, may reduce the light that reaches each eye. Other techniques offer glasses that have electronic shutters such that the image for the left eye is blocked from the right eye and vice versa. Lenticular prism lenses have been used on specially prepared printed pictures and interlaced displays to simulate a 3D object. However, lenticular lenses are fixed, so there is no provision for adjusting for the viewer&#39;s position or for the distance between the viewer&#39;s eyes, which may result in ghost images or less than optimal viewing.  
           [0004]    There is, therefore, a need for a method and a system that allows a user to view images on a display that has been adapted to present 3D images such that the viewer does not have to wear special glasses, and the viewer has adjustments that allow for variations in viewing distance and the viewer&#39;s own eye characteristics to be compensated.  
         SUMMARY OF THE INVENTION  
         [0005]    A display screen on which a back projected image is displayed is modified to incorporate an electro-mechanical structure that allows the light from each pixel to be selectively directed to a viewer&#39;s left and right eyes in response to control signals. A prism/lense element is provided for each pixel which may be selectively rotated so that light from the pixel may be directed to first one eye then to the other eye. X-Y control signals allow each prism/lense element to be individually addressed. The control signal for each pixel comprises X and Y voltages. If a voltage difference level is provided between particular X and Y lines, then the corresponding prism/lense element for the pixel is “addressed,” and the prism/lense element may be rotated changing the direction of the light from the pixel depending on the magnitude of the voltage. Single pixels or groups of pixels may be addressed at any one time. Whole image frames representing left and right eye views may be alternately presented for the left and right eyes of the viewer, or pixel data for left and right eye images may be selectively accessed from a memory device. When the left eye frame or left eye pixel data is present, the corresponding prism/lense elements are rotated by selectively applying control signals so that each left eye pixel is directed to the viewer&#39;s left eye. Likewise, when the right eye frame or right eye pixel data is present, the prism/lense elements are rotated by selectively applying control signals so that each right eye pixel is directed to the viewer&#39;s right eye. The levels of the control signals may be selectively controlled by algorithms to compensate for display anomalies and to allow a viewer to personalize the display. By selectively applying control signals synchronized with the particular displayed images, the viewer perceives a 3D presentation. One embodiment of the present invention uses piezoelectric elements to rotate the individual prism/lense elements. In another embodiment of the present invention, a prism/lense element may be designed to be rotated using electrostatic force.  
           [0006]    The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:  
         [0008]    [0008]FIG. 1 is a diagram illustrating light from pixels being directed to a viewer&#39;s left and right eyes by prism/lense elements;  
         [0009]    [0009]FIG. 2A and FIG. 2B illustrate an embodiment of the present invention where a piezoelectric element is used to deflect a beam supporting a prism/lense element;  
         [0010]    [0010]FIG. 3 illustrates an X-Y addressing of individual pixels;  
         [0011]    [0011]FIG. 4 illustrates an embodiment of the present invention for activating a piezoelectric element used to rotate prism/lense elements;  
         [0012]    [0012]FIG. 5A and FIG. 5B illustrate an embodiment of the present invention for addressing an electrostatic element used to rotate a prism/lense element;  
         [0013]    [0013]FIG. 6 illustrates various layers suitable for use in a micro-electronic mechanical (MEMS) process for making embodiments of the present invention;  
         [0014]    [0014]FIG. 7A and FIG. 7B illustrate another embodiment of the present invention where a piezoelectric element is used to deflect a beam supporting a prism/lense element;  
         [0015]    [0015]FIG. 8A, FIG. 8B and FIG. 8C illustrate another embodiment of the present invention with a piezoelectric element for rotating a prism/lense element; and  
         [0016]    [0016]FIG. 9 is a block diagram of a data processing system suitable for operating a display with selectable prism/lense elements according to embodiments of the present invention.  
         [0017]    [0017]FIG. 10 is a flow diagram of method steps for using embodiments of the present invention to display a 3D image.  
     
    
     DETAILED DESCRIPTION  
       [0018]    In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. In other instances, well-known circuits have been shown in block diagram form in order not to obscure the present invention in unnecessary detail. For the most part, details concerning timing considerations and the like have been omitted in as much as such details are not necessary to obtain a complete understanding of the present invention and are within the skills of persons of ordinary skill in the relevant art.  
         [0019]    Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.  
         [0020]    Most displays utilized on computer or television systems use techniques where the image impinges on the back side of a display screen and the light from the display screen is then received by a viewer&#39;s eyes. A cathode ray tube (CRT) uses electron beams to excite phosphors on the inside of the face of the CRT to generate various colors of light (photons), which in turn are received by the viewer&#39;s eyes. Other displays use various liquid crystal display (LCD) technologies to produce thin flat displays. Many of the LCDs are digital in that the individual picture elements (pixels) are addressable. Sometimes the switches that are used to address the individual pixels are integrated very close to each pixel using thin film transistor (TFT) technology.  
         [0021]    While embodiments of the present invention may be usable with different types of displays, it is described herein with respect to the LCD technology, as this technology lends itself to processes where all the elements necessary for the display are integrated onto the LCD panel. The LCD technology is used in the following to further explain embodiments of the present invention; however, it is understood that the present invention is not limited to LCD displays.  
         [0022]    Three dimensional (3D) displays have been described for many years. Most techniques comprise creating an image for the right eye and a separate image for the left eye and then using some means for directing the images to their corresponding eye. The 3D displays that generate entire images for the left and right eyes usually require some method to selectively mask the respective eyes when their image is not present. Glasses that have electronic shutters (e.g., using LCD techniques) are often used. Other techniques effectively break the image frame into strips, where alternating strips are obtained from the image for the right and left eyes. Lenticular prisms have been integrated on the face of such a display to direct the left frame strips to the left eye and the right frame strips to the right eye. Since each eye only receives half the frame, the image intensity and contrast may be sacrificed. These techniques also do not have an easy way of adjusting for the variations in an individual&#39;s viewing preferences.  
         [0023]    Embodiments of the present invention use a directing element on individual pixels so an entire frame may be presented for each eye. In an embodiment of the present invention, the display screen is made using LCD display technology. Additional process steps are used to add electro-mechanical prism/lense element structures, which are addressable with “X” and “Y” voltage lines. Each prism/lense element is designed so that the X-Y voltage lines may be used to activate and then control a position of the prism/lense element so that the light of a pixel may be directed to the right or to the left eye. Since the prism/lense elements are individually controlled, different pixels may receive different levels of control so that viewing anomalies of a viewer display screen combination may be compensated or adjusted.  
         [0024]    Frames of a display are presented to a viewer at a relatively slow rate. For example, video is presented at approximately 30 frames per second. As the frame presentation rate increases, less “flicker” is observed. Flicker occurs when the frame rate is such that a viewer is able to discern the individual frames changing. Since a prism/lense element of the present invention may be controlled individually, an entirely different 3D display methodology is possible. The image frames, which are arrays of digital data representing the intensity and color content of the individual pixels, may be stored in memory. A 3D display, according to an embodiment of the present invention, would supply a light value for each pixel corresponding to its left or right eye data and a control signal to the pixel indicating to which eye the pixel is directed. All the pixels for the image are not required to be directed to the left or right eye at any one time. Rather, the light value data from the memory may be randomly retrieved and supplied to the pixels. However, the rate at which the pixel data is supplied would be fast enough so that the viewer&#39;s eyes do not discern the individual pixels switching from right to left eye data. Embodiments of the present invention, where the light from individual pixels may be controllably switched from one eye to the other, allow many different possibilities in the control of image display.  
         [0025]    If a frame of an image is presented for a time T before it changes, then for a time equal to T/2 the prism/lense elements will direct a left pixel light value to the left eye, and for a time T/2 the prism/lense elements will direct a right pixel light value to the right eye. If the prism/lense elements may be moved from a left orientation to a right orientation in a time T D , the time T may be divided into T/T P =K time slots. In this case T P &gt;&gt;T D  to insure that the duration at a particular eye position is longer than the time to switch between eye positions. K/2 of these time slots are allotted for the left eye and K/2 for the right eye. During each of the K/2 time slots, light from half of the pixels are directed to the right eye and light from the other half are directed to the left eye. However, embodiments of the present invention allow a random allocation of which particular pixels in each K/2 time slot are directed to which eye. This may reduce the apparent flicker as seen be a viewer.  
         [0026]    [0026]FIG. 1 illustrates two pixels  103  and  110  of a display  100 . Pixel  103  has a prism/lense element (PL)  106  and pixel  110  has PL  111 . Exemplary PL element  106  has a dashed line  118  identifying the area below the dashed line as its prism part and the curved surface  116  as its lense part. Dashed line  118  also shows that the lense surface  116  is at an angle with bottom surface  119 . A light ray  108  from pixel  103  impinges perpendicular to the bottom surface  119 . Because light ray  108  is perpendicular to bottom surface  119 , its path as light ray  112  through the prism portion of PL  106  is not altered. However, when light ray  112  hits lense surface  116  the light is “bent” by angle  115  to the right towards a viewer&#39;s left eye  102 . Initial light ray  108  is altered and results in light ray  104  which is directed towards the viewer&#39;s left eye. Left and right are referenced to the viewer&#39;s left and right sides.  
         [0027]    The spacing S  120  between a typical viewer&#39;s eyes is approximately two inches, and the viewer&#39;s position H  121 , relative to the display  100 , is approximately twelve inches. A calculation shows that angle  115  would be in the range of five to ten degrees to direct a light ray towards left eye  102 . The spacing between pixels  103  and  110  is greatly exaggerated to show detail. From a viewer&#39;s perspective, adjacent pixels  103  and  110  would be considered as nearly the same point source of light.  
         [0028]    Pixel  110  has corresponding PL  111  which is shown rotated by an angle  113 . PL  111  is rotated to show how a light ray  107  is directed to the left towards right eye  101 . If PL  111  was in the same position as PL  106 , light ray  107  would also be directed to the right. By rotating PL  111  by an angle  113 , light ray  107  does not impinge perpendicular to the bottom surface  122  of PL  111 , and Snell&#39;s law dictates that light ray  107  is “bent” proportional to the ratio of the indices of refraction of air and the material of PL  111 . Light ray  107  follows a path shown by light ray  109  to the lense surface  117 . Light ray  109  is then bent back to the right again, however the net result is that the original light ray  107  is directed to the right eye  101  as light ray  105 . PL  111  may be rotated a sufficient angle  113  so that the resulting light ray angle  114  is equivalent to light ray angle  115 .  
         [0029]    The bending of light rays and the rotation of the prism/lense elements is the mechanism that directs the light rays towards a particular eye of a viewer. The lense portion of the prism/lense element serves to focus the light rays that strike the lense surfaces (e.g., lense surfaces  116  and  117 ) towards a central focal point. Light rays that are off center of PL  106  and PL  111  are directed to a light focal point. A viewer would not see much light with their right eye from pixels directed to their left eye and vice versa.  
         [0030]    Exemplary elements PL  106  and PL  111  are complex structures, which may be integrated onto a display surface to enable compensated 3D image viewing. Details for fabricating prism/lense elements (e.g., PL  106  and PL  111 ) are discussed related to FIG. 6. A manufacturing method known as Micro-Electro-Mechanical Systems (MEMS) technology may be used in the process of fabricating an array of prism/lense elements according to embodiments of the present invention.  
         [0031]    [0031]FIG. 2A and FIG. 2B illustrates a prism/lense element PL  210  for directing light from pixel  201 . PL  210  is coupled to a beam  204  which in turn is coupled to base  205 . Base  202  represents the base of another prism/lense element adjacent to PL  210  which is not completely shown. An opaque material layer  203  may be deposited around the opening to exemplary pixel  201  so that light from pixel  201  is directed primarily to PL  210 . Material has been removed under PL  210  and beam  204  forming cavity  208 . PL  210  is therefore free to move downwards towards pixel  201 . A piezoelectric element (PZE)  212  has been formed on beam  204  with corresponding electrical contacts  211  and  213 . A voltage may be applied across the length of PZE  212  which will cause voltage induced elongation (or contraction) stresses in beam  204 . Since only one surface of PZE  212  is free to move, the voltage potential energy will be converted to a mechanical bending force that will bend beam  204  downwards thus causing a rotation and translation deflection in PL  210  as shown in FIG. 2B. In FIG. 2A, light ray  206  impinges perpendicular to surface  217  and follows path  207  to the surface  214  of the lense portion of PL  210 . At surface  214  light ray  207  is bent to follow path  209  and is directed to the right. When PL  210  is rotated as shown in FIG. 2B, light ray  206  impinges on surface  217  at an angle and follows path  215  to surface  214 . Again, light ray  215  is bent back to the right following path  216 , however, the rotation of PL  210  has caused light ray  206  to have a net direction to the left. PL  210 , as shown and controlled in FIG. 2A and FIG. 2B, is one embodiment of the present invention where the prism/lense element formed over a pixel is controlled by piezoelectric forces.  
         [0032]    [0032]FIG. 3 illustrates a partial array of pixels  306 - 311 . If the pixels  306 - 311  each have a voltage actuated prism/lense element (e.g., like PL  210 ), then selectively applying one potential of a voltage to X-lines  301 - 303  and the other potential to Y-lines  304 - 305  allows each pixel to be independently controlled. Y-lines  304 - 305  and X-lines  301 - 303  may be used to varying voltage levels such that the voltage difference between the X-Y line pairs are controlled in groups (e.g., rows or columns) or individually.  
         [0033]    [0033]FIG. 4 illustrates a partial array of pixels  405 - 408  arranged as in FIG. 3 with corresponding prism/lense elements (PL)  401 - 404  which may be configured like PL  210  shown in FIG. 2A and FIG. 2B. PL  401 - 404  may be attached to corresponding beams  413 - 416  where beams  413 - 416  have corresponding piezoelectric elements PZE  409 - 412 . Control voltage lines Y 1   421 , Y 2   422 , X 1   423  and X 2   424  are used to select and control PZE  409 - 412 . X 1   423  and X 2   424  may be used to supply a ground and Y 1   421  and Y 2   422  may be used to supply the same or different voltage levels depending on the control algorithm used. The voltage across X-Y pairs may also be polarity reversed to cause piezoelectric elements (e.g., like PZE  409 - 412 ) to contract for additional control. Cavities  417 - 420  are similar to cavity  208  illustrated in FIG. 2A and FIG. 2B.  
         [0034]    [0034]FIG. 5A and FIG. 5B illustrate another embodiment of the present invention where PL  505  is controlled by electro-static forces. PL  505  is coupled to beam  511  which extends over cavity  512 . The underside of beam  511  has a metal layer  510  and the corresponding area under beam  511  on base  514  has a metal layer  509  which is isolated from layer  510 . Opaque material  508  may be used to block light of pixel  501  from other than PL  505 . Like PL  210  in FIG. 2A and FIG. 2B, PL  505  may be rotated by bending beam  511  in response to a control voltage addressing prism/lense element PL  505 . When a voltage is applied across metal layers  510  and  509 , the electrostatic forces will try to close gap  513 . As the beams bends, the capacitance between the plates increases and energy is drawn from the source supplying the voltage to metal layers  510  and  509  to do the mechanical work. In this manner, a light ray  502  which normally follows a path  503  to path  504  (FIG. 5A) is deflected to follow path  506  and path  507  (FIG. 5B). Metal layers  510  and  509  may be connected to an X-Y addressing configuration as illustrated in FIG. 3 and FIG. 4.  
         [0035]    [0035]FIG. 6 is used to illustrate one method by which a prism/lense element structure (PL)  600  may be fabricated using a MEMS process according to embodiments of the present invention. MEMS refers primarily to a process applied to semiconductor chips wherein a top layer of mechanical devices such as mirrors or fluid sensors are formed, however, the techniques may be applied to larger structures. In the research labs since the 1980s, MEMS devices began to materialize as commercial products in the mid-1990s. They are used to make pressure, temperature, chemical and vibration sensors, light reflectors and switches as well as accelerometers for air-bags, vehicle control, pacemakers and games. They are also used in the construction of micro-actuators for data storage as well as read/write heads, and they are used in all-optical switches to forward light beams by reflecting them to the appropriate output port.  
         [0036]    Referring to FIG. 6, pixel  602  is representative of one of an array of pixels making up the face of a display modified according to embodiments of the present invention. In a first step in fabricating a prism/lense element  600 , an opaque material  601  is deposited over substrate  614  which contains pixel element  602 . A resist material (not shown) is then deposited over the opaque material  601  and then exposed and developed to allow a window  603  over pixel  602  to be opened using an appropriate etch material. A material layer  605 , used to make PL  600 , is then deposited. A resist material (not shown) is applied over layer  605  and exposed and developed so that an appropriate etch may be used to open window  603  and window  604 . Next, a negative resist material is deposited in a layer  606 . Layer  606  again fills up window areas  603  and  604 . The negative resist material is formulated such that it must be exposed and developed before it becomes removable. If layer  606  has areas that are not exposed, then the material is not removable by a chemical etch. Layer  606  is exposed defining areas  607  and then the material in areas  607  is removed. The areas  607  are then filled with a material like layer  605 . At this point, the remaining area of resist layer  606  is exposed so that it may be removed in a later step. Layer  608  is then deposited with the same material as layer  605 . At this point layer  608 , areas  607  and layer  605  are joined as like material. A resist layer (not shown) is then applied over layer  608  and a pattern is made so material for piezoelectric element  609  may be deposited. Another resist layer (not shown) is applied and another pattern is made so material for contacts  610  and  611  and contact lines coupled to contacts  610  and  611  may be deposited. Once piezoelectric element  609  is in place, another resist layer (not shown) is applied to a sufficient thickness such that the prism/lense element material may be deposited to a thickness  613  over material layer  608 . The material for PL  600  is formulated as a negative resist material so that when exposed it may be etched. In formulating the lense surface  612  of PL  600 , the intensity of the expose energy beam is adjusted so that the material of lense surface  612  is variably developed such that the material across the lense face  612  has different depths of development. When the material of PL  600  is etched, the lense surface  612  is formed as variable depth material is removed. In a last step, the previously exposed material in layer  606 , under PL  612  and beam  616 , is removed leaving PL  600  cantilevered over cavity  617 . The process steps discussed relative to FIG. 6 represent one possible process for fabrication of PL  600  according to embodiments of the present invention. Other processes may be used to make controllable prism/lense elements (e.g., like PL  600 ) depending on materials selected for making various layers.  
         [0037]    [0037]FIG. 7A and FIG. 7B illustrate another embodiment of the present invention using piezoelectric forces to control a prism/lense element. Pixel PL  705  is fabricated over pixel  701 . Opaque layer  708  blocks light of pixel  701  from all but PL  705 . In FIG. 7A, an exemplary light ray  702  impinges perpendicular to the bottom surface  717  of PL  705  and follows path  703  to lense surface  715  where light ray  703  is bent to follow path  704 . PL  705  is supported on beam  711  attached to base  714 . A gap  713  under beam  711  has PZE  716  with metal contacts  710  and  709 . Contacts  710  and  709  allow a potential to be applied across PZE  716 . Depending on the magnitude and polarity of the potential applied to contacts  710  and  709 , PZE  716  will expand or contract, deflecting beam  711 . In FIG. 7B, PZE  716  is shown contracted thereby deflecting beam  711  and PL  705  downwards toward pixel  701 . As explained before, this causes light ray  702  to follow paths  706  and  707  whereby light from pixel  701  is directed to the left. Sequences of process steps like those explained in FIG. 6 may be used to fabricate PL  705 , beam  711  and corresponding PZE  716  with contacts  710  and  709 . Contacts  710  and  709  may be coupled to an X-Y addressing and control as shown in FIG. 3 and FIG. 4 and used with alternate left and right eye images to generate a 3D presentation. The magnitude of the voltage across contacts  710  and  709  may be varied to allow the deflection and rotation of individual pixels (e.g.,  701 ) to be optimized for a particular viewer as explained within embodiments of the present invention.  
         [0038]    [0038]FIG. 8A, FIG. 8B and FIG. 8C illustrate another embodiment of the present invention. FIG. 8A is a side view of a PL  801  supported above a pixel  809 . Piezoelectric elements (PZE)  806  and  808  support the edges of PL  801 . PZE  806  has contacts  802  and  805  and PZE  808  has contacts  803  and  804 . PL  801  is attached with an element  807  which is shown in a side view.  
         [0039]    [0039]FIG. 8B is a top view of PL  801  illustrating how element  807  is attached to two sides of PL  801 . Element  807  may be torsionally deflected to rotate PL  801  according to embodiments of the present invention.  
         [0040]    [0040]FIG. 8C illustrates PL  801  rotated by applying voltages across PZE  806  and PZE  808 . PZE  806  elongates and PZE  808  contracts and element  807  supporting PL  801  is twisted. The voltages applied to contacts  802 - 805  and  803 - 804  may be reversed to rotate PL  801  in the opposite direction. PL  801  may be fabricated with process steps like those discussed relative to FIG. 6.  
         [0041]    [0041]FIG. 9 is a high level functional block diagram of a representative data processing system  900  suitable for practicing the principles of the present invention. Data processing system  900 , includes a central processing system (CPU)  910  operating in conjunction with a system bus  912 . System bus  912  operates in accordance with a standard bus protocol, compatible with CPU  910 . CPU  910  operates in conjunction with random access memory (RAM)  914 . RAM  914  includes, DRAM (Dynamic Random Access Memory) system memory and SRAM (Static Random Access Memory) external cache. I/O Adapter  918  allows for an interconnection between the devices on system bus  912  and external peripherals, such as mass storage devices (e.g., a hard drive, floppy drive or CD/ROM drive) or a printer  940 . A peripheral device  920  is, for example, coupled to a peripheral control interface (PCI) bus, and I/O adapter  918  therefore may be a PCI bus bridge. User interface adapter  922  couples various user input devices, such as a keyboard  924 , mouse  926 , trackball  932  or speaker  928  to the processing devices on bus  912 . Display  938  which may be, for example, a cathode ray tube (CRT), liquid crystal display (LCD) or similar conventional display unit. Display adapter  936  may include, among other things, a conventional display controller and frame buffer memory. Data processing system  900  may be selectively coupled to a computer or telecommunications network  941  through communications adapter  934 . Communications adapter  934  may include, for example, a modem for connection to a telecom network and/or hardware and software for connecting to a computer network such as a local area network (LAN) or a wide area network (WAN). A LCD display  938  may be fabricated according to embodiments of the present invention with integrated controllable prism/lense elements (e.g., like PL  505 ) over each pixel of LCD display  938 . Software applications may utilize the advantage of LCD display  938  by alternately supplying left and right eye image frames. Control signals, synchronized with the image frames, may be used to present a 3D image to a viewer. Also control signals may be applied to selectively adjust the angle of prism/lense elements on LCD display  938  to optimize a viewer&#39;s presentation.  
         [0042]    [0042]FIG. 10 is a flow diagram of method steps for displaying a stereoscopic 3D image using embodiments of the present invention. In step  1001 , pixel data for N/2 pixels of N pixels defining a first image frame for a viewer&#39;s left eye are randomly selected. In step  1002 , pixel data for N/2 pixels from N pixels defining the first image frame for a viewer&#39;s right eye are randomly selected. These N pixel data and corresponding control data for the optical elements corresponding to the selected pixel data are sent to the display for a time Tk in step  1003 . In step  1004 , the remaining N/2 data for the left eye view of the first image frame are selected and in step  1005  the remaining N/2 data for the right eye view of the first image frame are selected. In step  1006 , these N pixel data are sent to the display for a time Tk. In step  1007 , a test is done to determine if the sum of the time periods Tk equals an image frame time period T. If the sum of the times Tk equal the image frame time period T, then both the left and right views for the first image frame have been presented to the viewer for a time equal to the image frame period. When the left and right views have been displayed for a time equal to the image frame period T, the image frame data may change. In step  1009 , the data for the next image frame is accessed and a branch to step  1001  starts another display sequence. If in step  1007  the sum of the Tk time periods do not equal the image frame period T, then the present image frame has not been displayed for the required time, and in step  1008  a branch is taken back to step  1001  where image frame data is again selected for the present frame.  
         [0043]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.