Patent Publication Number: US-2023136176-A1

Title: System and apparatus for see-through display panels

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Pat. Application No. 16/277,787 filed Feb. 15, 2019, which is divisional of and claims the benefit of U.S. Pat. Application Serial No. 14/997,129 filed Jan. 15, 2016, which is a divisional of and claims the benefit of U.S. Pat. Application Serial No. 14/555,164 filed Nov. 26, 2014, and issued as U.S. Pat. No. 9,251,745 on Feb. 02, 2016, which is a divisional of and claims the benefit of U.S. Pat. Application Serial No. 12/756.984 filed Apr. 8, 2010 and issued as U.S. Pat. No. 8,922,897 on Dec. 30, 2014. which is a continuation-in-part of and claims the benefit of U.S. Pat. Application Serial No. 12/204,567 filed Sep. 4, 2008 and issued as U.S. Pat. No. 8,520,309 on Aug. 27, 2013, all of which are herein incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related to optics and, more specifically, is directed toward optical processing of display information and non-display information using display panels and a dual path contact lens. 
     DESCRIPTION OF THE RELATED ART 
     Current systems for optical processing of display information provided by a head-mounted display and non-display information provided by objects other than the head-mounted display may have characteristics that make them unattractive solutions for some applications. The twin requirements of a large field of view and a comfortable eye-to-system distance for the viewer results in multi-component optical systems where the final optical component has a large diameter. Such systems tend to be large, bulky and ill suited for applications where little space is available for processing the display information and the non-display information. For example, such systems are unattractive solutions for processing display and non-display information in a fighter pilot’s helmet where the space for the optical system is limited. 
     BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION 
     Various embodiments of the present invention provide systems and apparatus directed toward using a display panel to process display information and non-display information. Further embodiments utilize a display panel in conjunction with a contact lens assembly configured to process the display information. 
     In one embodiment of the invention, a display panel assembly is provided, comprising: a transparent substrate that permits light to pass through substantially undistorted: a reflector disposed on the transparent substrate; and a display panel aimed toward the reflector and substantially away from a human visual system, wherein the reflector reflects light emitted from the display panel toward the human visual system. The reflector may be a narrow band reflector or a polarization reflector. Additionally, the display panel assembly may further comprise a bandpass filter positioned adjacent to the display panel, wherein the bandpass filter limits bandwidths of light emitted from the display panel toward the narrow band reflector such that substantially no light passes through the narrow band reflector. The display panel may further comprise a polarization filter positioned adjacent to the display panel, wherein the polarization filter limits the polarity of light emitted from the display panel toward the polarization reflector such that substantially no light passes through the first polarization reflector. 
     In some embodiments, the display panel further comprises a first polarization filter positioned adjacent to the transparent substrate on a side facing opposite the human visual system and a second polarization filter positioned adjacent to the display panel, wherein the second polarization filter limits the polarity of light emitted from the display panel toward the narrow band reflector and the first polarization filter such that substantially no light passes through the first polarization filter. 
     According to another embodiment, a display panel assembly is provided, comprising: an electro-luminescent display that is transparent; a liquid crystal display that is transparent and segmented, wherein the liquid crystal display is mounted to the electro-luminescent display such that a segment of the liquid crystal display is substantially aligned with one or more pixels within the electro-luminescent display; and a control mechanism that varies a liquid crystal pixel gray level for the segment in order to modify an amount of ambient light passed through the electro-luminescent display. Depending on the embodiment, the electro-luminescent display may be an organic light emitting diode display. 
     In some embodiments, an algorithm modifies the liquid crystal pixel gray level based on a content of the electro-luminescent display. In other embodiments, an algorithm modifies the liquid crystal pixel gray level based on a brightness of the one or more pixels within the electro-luminescent display. In further embodiments, an algorithm modifies the liquid crystal pixel gray level based on a color of the one or more pixels within the electro-luminescent display. In additional embodiments, an algorithm modifies the liquid crystal pixel gray level based on a gaze angle of an eye of a viewer. In yet further embodiments, an algorithm modifies the liquid crystal pixel gray level based on time periods. 
     According to an additional embodiment, a display system is provided, comprising: a display assembly disposed on a head-borne apparatus, wherein the display assembly is positioned in close proximity to an eye of a viewer such that the eye is unable to focus on the display assembly unassisted, and the display assembly comprises a transparent display panel having pixels configured without focusing optics, thereby allowing light emitted by the pixels to diverge unfocused; and a contact lens having focusing optics that assists the eye in focusing on light emitted by the pixels of the transparent display panel. 
     According to another embodiment, a display panel assembly is provided, comprising: transparent display panel having a viewable side, the transparent display panel comprising a display pixel; a polarizer affixed to the viewable side; a transparent pixelated liquid crystal array affixed to the polarizer, the transparent pixelated liquid crystal array comprising at least one liquid crystal pixel that substantially aligns to the display pixel: and a control mechanism configured to electrically control the transparent display and the transparent pixelated liquid crystal array, wherein in a first time period, the control mechanism sets the display pixel to a predetermined brightness level and sets the liquid crystal pixel to a first orientation at every location where a display pixel is set to at least partially illuminated, and in a second time period, the control mechanism sets the display pixel to emit no light and sets the liquid crystal pixel to a second orientation. 
     In yet another embodiment, a display panel assembly is provided, comprising: a transparent electroluminescent panel having a first electroluminescent panel side and second electroluminescent panel side; a first transparent pixelated liquid crystal array having a first array side and a second array side, wherein a polarizer is affixed to both the first and second array sides, and the second array side with the polarizer is affixed to the first electroluminescent panel side, and ; a first transparent liquid crystal shutter panel having a first shutter panel side and a second shutter panel side, wherein the second shutter panel side is affixed to the first array side; and a first control mechanism configured to electrically control the transparent electroluminescent panel, the first transparent pixelated liquid crystal array, and first transparent liquid crystal shutter panel, wherein in a first time period, the control mechanism sets the first transparent liquid crystal shutter to a first polarization orientation and sets the first transparent pixelated liquid crystal array to a first gray level orientation proper for forming a desired image, and in a second time period, the control mechanism turns off the transparent electroluminescent panel and sets the first transparent liquid crystal shutter panel to a second polarization orientation. 
     In some such embodiments, the display panel assembly further comprises: a second transparent liquid crystal shutter panel affixed to the second electroluminescent panel side, wherein a polarizer is affixed to both sides of the second transparent liquid crystal shutter panel: and a second control mechanism configured to electrically control the second transparent liquid crystal shutter panel, wherein in a third time period, the second transparent liquid crystal shutter panel is set to block light from transmitting, and in a fourth time period, the second transparent liquid crystal shutter panel is set to allow light to transmit. In other such embodiments, the display panel assembly further comprises: a second transparent pixelated liquid crystal array affixed to the second electroluminescent panel side, wherein a polarizer is affixed to both sides of the second transparent pixelated liquid crystal array; and a second control mechanism configured to electrically control the second transparent pixelated liquid crystal array, wherein in a third time period, the second transparent pixelated liquid crystal array is set to a second gray level orientation proper for forming a second desired image, and in a fourth time period, the second transparent pixelated liquid crystal array is set to allow light to transmit. 
     In some embodiments, the transparent electroluminescent panel may comprise a multicolor array that substantially aligns to pixels in the first transparent pixelated liquid crystal array, or a plurality of colored transparent electroluminescent panels, and the first time period comprises a plurality of sub-periods such that: each colored transparent electroluminescent panel is of a different color, each colored transparent display is is turned on during a different sub-period, and the first transparent liquid crystal shutter panel is set to a different orientation during each sub-period. 
     Accord to a further embodiment, a display panel assembly provided, comprising: a transparent substrate having a semi-reflective surface that reflects light in multiple directions; a transparent cover bonded to the semi-reflective surface using an adhesive having a refraction coefficient similar to that of the transparent substrate; and an image projector configured to project an image onto the semi-reflective surface. The semi-reflective in such an embodiment surface may be a narrow spectral band reflector. In some such embodiments, the image projector comprises a narrow spectral band filter configured to project light that is narrower in wavelength than light reflected from the narrow spectral band reflector. Additionally, the semi-reflective surface may be a polarization reflector that reflects light of a first polarization and passes light of a second polarization. In some such embodiment, the image projector comprises a polarization filter configured to project light of a first polarization. 
     According to another embodiment, a display panel assembly is provided, comprising: a transparent substrate having a semi-reflective surface that reflects light in multiple directions; a transparent cover bonded to the semi-reflective surface using an adhesive, wherein the adhesive has a refraction coefficient similar to that of the transparent substrate: a polarizer affixed to the transparent cover; a liquid crystal pixel array affixed to the polarizer; and a polarized illumination source having a first polarization orientation, wherein the polarized illumination source illuminates the semi-reflective surface through the liquid crystal pixel array. The semi-reflective surface in some such embodiments may be a narrow spectral band reflector. 
     According to an additional embodiment, a display panel assembly is provided, comprising: a transparent substrate having a semi-reflective surface that reflects light in multiple directions; a transparent cover bonded to the semi-reflective surface using an adhesive, wherein the adhesive has a refraction coefficient similar to that of the transparent substrate; a light spreading relay configured to relay in a uniform manner light entering from a first relay side onto the semi-reflective surface; a liquid crystal pixel array affixed nearer the viewer a polarizer affixed to the liquid crystal pixel array nearest the viewer; and a polarized illumination source having a first polarization orientation, wherein the polarized illumination source illuminates the semi-reflective surface through the light spreading relay. In some such embodiments, a second polarizer is affixed to the transparent substrate and has a second polarization orientation. In other such embodiments, the semi-reflective surface is a narrow spectral band reflector. 
     Other features and aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features in accordance with embodiments of the invention. The summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments of the invention. These drawings are provided to facilitate the reader’s understanding of the invention and shall not be considered limiting of the breadth, scope, or applicability of the invention. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale. 
       Some of the figures included herein illustrate various embodiments of the invention from different viewing angles. Although the accompanying descriptive text may refer to such views as “top,” “bottom” or “side” views, such references are merely descriptive and do not imply or require that the invention be implemented or used in a particular spatial orientation unless explicitly stated otherwise. 
         FIG.  1 A  is a block diagram of an example apparatus to receive and process display information and non-display information in accordance with some embodiments of the present invention. 
         FIG.  1 B  is a block diagram of the example apparatus (shown in  FIG.  1 A ) coupled to a human visual system in accordance with some embodiments of the present invention. 
         FIG.  1 C  is a block diagram of an example apparatus including the apparatus (shown in  FIG.  1 A ), and further including a display to provide the display in accordance with some embodiments of the present invention. 
         FIG.  1 D  is a block diagram of an example apparatus including the apparatus (shown in  FIG.  1 A ), wherein at least one of the one or more filters (shown in  FIG.  1 A ) includes a non-display path notch filter or a non-display path polarizing filter and further including the display (shown in  FIG.  1 C ) to provide the display information (shown in  FIG.  1 A ) in accordance with some embodiments of the present invention. 
         FIG.  1 E  is a block diagram of an example apparatus including the apparatus (shown in  FIG.  1 A ), wherein the one or more filters include a non-display path polarizing filter (shown in  FIG.  1 D ) and further including the display (shown in  FIG.  1 C ) in accordance with some embodiments of the present invention. 
         FIG.  2 A  is a block diagram of an example apparatus to receive and process the display information and the non-display information in accordance with some embodiments of the present invention. 
         FIG.  2 B  is a block diagram of the example apparatus (shown in  FIG.  2 A ) coupled to the human visual system (shown in  FIG.  1 B ) in accordance with some embodiments of the present invention. 
         FIG.  2 C  is a block diagram of an example apparatus including the apparatus (shown in  FIG.  2 A ), and further including the display (shown in  FIG.  1 C ) to provide the display information in accordance with some embodiments 
         FIG.  2 D  is a block diagram of an example apparatus including the apparatus (shown in  FIG.  2 A ), wherein at least one of the one or more controllable optical materials includes a photochromic material or an electrochromic material and further including the display (shown in  FIG.  1 C ) to provide the display information and one or more optical material activation signals in accordance with some embodiments of the present invention. 
         FIG.  3    is an example apparatus including a substrate including an optical path having one or more zone plates to receive display information and non-display information in accordance with some embodiments of the present invention. 
         FIGS.  4 A and  4 B  (diametrical section of contact lens shown in 4A) are illustrations of an example contact lens including the display information optical path and the non-display information optical path in accordance with some embodiments of the present invention. 
         FIG.  5    is an illustration of an example display optically coupled by the contact lens to the human visual system to illustrate processing non-display information using wavelength filters in accordance with some embodiments of the present invention. 
         FIG.  6    is an illustration of an example display optically coupled by the contact lens to the human visual system to illustrate processing display information using wavelength filters in accordance with some embodiments of the present invention. 
         FIG.  7    is an illustration of an example display optically coupled by the contact lens to the human visual system to illustrate processing to combine non-display information and display information using wavelength filters in accordance with some embodiments of the present invention. 
         FIG.  8    is an illustration of an example display optically coupled by the contact lens to the human visual system to illustrate processing non-display information using polarizing filters in accordance with some embodiments of the present invention. 
         FIG.  9    is an illustration of an example display optically coupled by the contact lens to the human visual system to illustrate processing display information using polarizing filters in accordance with some embodiments of the present invention. 
         FIGS.  10 A and  10 B  (diametrical section of illustration shown in 10A) are illustrations of an example contact lens including one or more zone plate filters in accordance with some embodiments of the present invention. 
         FIG.  11    is an illustration of an example display optically coupled by the contact lens to the human visual system to illustrate processing display information and non-display information using the one or more zone plate filters in accordance with some embodiments of the present invention. 
         FIG.  12    is an illustration of an example apparatus including a substrate, a substantially transparent pixel unit and an organic light emitting diode unit in accordance with some embodiments of the present invention. 
         FIG.  13    is a flow diagram of an example method including enabling and disabling transmission of display information and transmission of non-display information in accordance with some embodiments of the present invention. 
         FIG.  14    is a flow diagram of an example method including polarizing display and non-display information and illuminating a contact lens with the polarized display and non-display information in accordance with some embodiments of the present invention. 
         FIG.  15    is an illustration of an example configuration of a contact lens and a display panel reflected off a narrow spectral band beam splitter, in accordance with one embodiment of the present invention. 
         FIG.  16    is an illustration of an example configuration of a contact lens and a display panel reflected off a polarized beam splitter, in accordance with one embodiment of the present invention. 
         FIG.  17    is an illustration of an example configuration of a contact lens and display pixels in front of an LCD display panel, in accordance with one embodiment of the present invention. 
         FIG.  18    is an illustration of an example configuration of a contact lens and an electroluminescent display panel that is polarized by an array of LCD pixels, in accordance with one embodiment of the present invention. 
         FIG.  19    is an illustration of an example configuration of a contact lens and an LCD panel that is backlit by an electroluminescent panel, in accordance with one embodiment of the present invention. 
         FIG.  20    is an illustration of an example configuration of a contact lens and an LCD panel that is backlit by an electroluminescent panel with a second LCD panel, in accordance with one embodiment of the present invention. 
         FIG.  21    is an illustration of an example configuration of a contact lens and an image projected onto a partially reflective panel, in accordance with one embodiment of the present invention. 
         FIG.  22    is an illustration of an example configuration of a contact lens and an LCD panel that is illuminated by light projected onto a partially reflective back panel, in accordance with one embodiment of the present invention. 
         FIG.  23    is an illustration of an example configuration of a contact lens and an LCD panel that is side-illuminated through a light spreader, in accordance with one embodiment of the present invention. 
     
    
    
     The figures are not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration, and that the invention be limited only by the claims and the equivalents thereof. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION 
     The present invention is directed toward systems and apparatus that use a display panel to provide display information and non-display information to a human eye. In some embodiments, a display panel in accordance with the present invention is configured to combine and process non-display information originating from the real world environment, with display information emanating from the display panel. In further embodiments, the display panel in accordance with the invention is used in conjunction with a contact lens to combine and process non-display information with display information. As will be disclosed by the following description, depending on the embodiment, the display panel of the invention may be positioned off-axis with respect to axial alignment of the human visual system (e.g., human eye) which perceives images produced by the display panel (i.e., light rays emanating from the display panel). 
     The term human visual system as used in the following description includes the components of the human body that facilitate vision including, but not limited to, the cornea, the retina, the pupil, the iris, the eye lens, sclera, and the optic nerves. 
     The term substrate as used in the following description includes any material or substance used to form an optical component such as a contact lens. The term zone plate includes an optical component that focuses light by diffraction. The term display information optical path includes the optical path traversed in a substrate by display information. The term non-display information optical path includes the optical path traversed in a substrate by non-display information. For some embodiments, non-display information may include what is perceived in the real world by a human eye. The term optically coupled includes two or more optical components connect by an optical path. 
     The term non-display information path optical power includes the optical power provided in a substrate for an optical signal passing through the non-display information path. The term substantially zero power includes an optical power that has substantially no effect on an optical signal. The term normal power is the optical power necessary to provide correction in an optical system, such as a human visual system, for defects in the optical system. The term close power is the optical power necessary to provide correction in an optical system, such as a human visual system, for viewing at a close distance. 
     The term electromagnetic radiation includes energy in the form of transverse electric and magnetic waves. The term electromagnetic radiation includes electromagnetic radiation in the visible spectrum. The term illuminating includes directing or transmitting electromagnetic radiation to a target. 
     The term filter includes apparatus or methods for selectively transmitting electromagnetic radiation. The term characteristic feature includes detectable traits, such as narrow bandwidth or polarization, by which signals can be distinguished. 
     The term notch filter includes a filter that blocks electromagnetic radiation over a substantially continuous narrow band of frequencies. The term non-display path notch filter includes a notch filter included in the non-display path of a substrate. 
     The term bandpass filter includes a filter that transmits electromagnetic radiation over a substantially continuous but finite band of frequencies. The term display path bandpass filter includes a bandpass filter included in the display path of a substrate. 
     The term polarizing filter includes a filter that polarizes electromagnetic radiation. The term display path polarizing filter includes a polarizing filter included in the display information path of a substrate. The term non-display path polarizing filter includes a polarizing filter included in the non-display information path of a substrate. The term shutter includes a controllable polarizing filter. The term substantially opaque filter includes a filter that blocks all or nearly all of the information received by the filter. 
     The term display includes any apparatus capable of generating information in the form of electromagnetic radiation. The term organic light emitting diode display includes one or more light-emitting diodes whose light emitting layer includes a film of one or more organic compounds. The term display information includes information provided by a display. 
     The term controllable optical materials includes materials whose optical properties, such as opacity, can be controlled. The term photochromic material includes materials whose optical properties can be controlled by an optical signal. The term electrochromic material includes an optical material whose properties can be controlled by an electrical signal. The term optical material activation signal includes signals to control the optical properties of a controllable optical material. 
     The term a pattern of pixel sites includes the organization of pixel sites on a substrate. The term substantial transparent pixel unit includes a portion of a display that transmits electromagnetic radiation generated outside the display. The term checkerboard pattern includes an alternating pattern similar to the pattern of a checkerboard. 
     In some embodiments, as illustrated and described herein, information provided by a head-mounted display, referred to as display information, and information provided by objects other than the head-mounted display, referred to as non-display information, are received at a contact lens included in a human visual system. A head-mounted display may include an organic light emitting diode display to provide the display information. The contact lens in combination with the human visual system provides images of the display information and the non-display information to the retina of the human visual system. The display information may include, for example, text information, non-text information or other visual information. The non-display information may include, for example, landscape information, non-landscape information, and other visual information. 
     The contact lens includes a display information optical path and a non-display information optical path. The display information optical path provides a contact lens transmission path between the head-mounted display and the human visual system for the display information transmitted by the head-mounted display. The display information optical path forms a substantially cylindrical central region of the contact lens. The display information optical path in the contact lens can provide power to assist the human visual system in focusing objects positioned close to the human lens. 
     The non-display information optical path provides a contact lens transmission path between the source of the non-display information and the human visual system for the non-display information. The non-display information optical path forms a substantially annular ring surrounding the cylindrical central region of the display information optical path. A filter is included in the non-display information optical path to substantially block display information from being transmitted through the non-display information optical path. The non-display information optical path in the contact lens may provide correction for defects, such as nearsightedness, farsightedness, and astigmatism in the human visual system. 
     The display information and the non-display information may be polarized to different polarizations to provide for distinguishing between the display information and the non-display information. Polarizing the display information and the non-display information enables independent processing of the display information and non-display information at the contact lens and enables tune-domain multiplexing in the transmission of the display information and the non-display information to the contact lens. The time-domain multiplexed display information and non-display information when processed by the human visual system are perceived as a single image. Further detailed description of these and other embodiments is provided below. 
       FIG.  1 A  shows a block diagram of an apparatus  101  to receive and process display information  103  and non-display information  105  in accordance with some embodiments. The apparatus  101  includes a substrate  107  including a display information optical path  109  to receive the display information  103  and including a non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes a display information path optical power  113 . The non-display information optical path  111  includes one or more filters  115  and a non-display information path optical power  117 . 
     The substrate  107  is not limited to being formed from a particular material or combination of materials. Materials suitable for use in forming optical components, such as lenses, may be used in forming the substrate  107 . Exemplary materials suitable for use in forming the substrate  107  include gels, such as silicone hydrogels, glasses, plastics, and polymers, such as polymethyl methacrylate and polymacon. The substrate  107  is not limited to a particular type of optical component. In some embodiments, the substrate  107  includes a substrate or blank suitable for forming one lens, such as a contact lens. In some embodiments, the substrate  107  includes one or more optical components or lenses, such as focusing lenses, formed from one or more optical materials. In some embodiments, the substrate  107  is formed from a flexible material conformable to the shape of a human cornea. In some embodiments, the substrate  107  is formed by filling a contact lens mold with one or more liquid polymers. 
     The display information  103  includes electromagnetic radiation, such as visible light, having at least one characteristic feature lacking in the non-display electromagnetic radiation of the non-display information  105 . For example, in some embodiments, the display information  103  includes electromagnetic radiation having a narrow spectral bandwidth while the non-display information  105  includes electromagnetic radiation having a broad spectral bandwidth. Narrow spectral bandwidth and broad spectral bandwidth are relative terms. In some embodiments, for two signals, the signal having the narrower spectral bandwidth information is the signal having a narrow spectral bandwidth and the signal having the broader spectral bandwidth information is the signal having a broad spectral bandwidth. In some embodiments, narrow spectral bandwidth information includes information having a bandwidth of between about a few nanometers and a few tens of nanometers. In some embodiments, broad spectral bandwidth information includes information having a bandwidth greater than about a few tens of nanometers. Thus, the non-display electromagnetic radiation having a broad spectral bandwidth lacks the characteristic feature -- narrow spectral bandwidth -- included in the display information  103 . 
     As a second example, in some embodiments, the display information  103  includes electromagnetic radiation having a display information polarization, such as right-handed circular polarization, and the non-display information  105  includes unpolarized information. Thus, the non-display information  105  including the non-display electromagnetic radiation having the unpolarized information lacks the characteristic feature -- right handed circular polarization -- included in the display information  103 . 
     The display information optical path  109  is included in the substrate  107  and is formed from an optical material or combination of materials. The display information optical path  109  is not limited to being formed from a particular optical material or combination of materials. Materials suitable for use in forming the substrate  107  are suitable for use in forming the display information optical path  109 . The materials used to form the display information optical path  109  may differ from the one or more materials used to form the substrate  107 . 
     In operation, the display information optical path  109  receives and transmits electromagnetic information, such as the display information  103 . When coupled to a human visual system (as shown in  FIG.  1 B ), the display information optical path  109  receives the display information  103  and assists the human visual system to substantially focus the display information  103  to a retina in the human visual system. 
     The non-display information optical path  111  is included in the substrate  107  and is formed from an optical material or combination of materials. The non-display information optical path  111  is not limited to being formed from a particular optical material or combination of materials. Materials suitable for use in forming the substrate  107  are suitable for use in forming the non-display information optical path  111 . The materials used to form the non-display information optical path  111  may differ from the one or more materials used to form the substrate  107 . 
     In operation, the non-display information optical path  111  receives the non-display information  105  and when coupled to a human visual system (as shown in  FIG.  1 B ) substantially focuses the non-display information  105  to a retina in the human visual system. The non-display information  105  includes any information, such as visible objects, not included in the display information  103 . In some embodiments, the non-display information  105  is provided from objects more distant from the human visual system than the source of the display information  103 . For example, in some embodiments, the display information  103  is provided to a human visual system from a head-mounted display located between about 5 millimeters and about 200 millimeters from the cornea, and the non-display information  105  is provided to the human visual system from a source located at a distance of greater than about 200 millimeters from the cornea. 
     The one or more filters  115  included in the non-display information optical path  111  substantially block the display information  103  while substantially transmitting the non-display information  105 . Each of the one or more filters  115  is sensitive to a physical characteristic, such as wavelength, frequency, or polarization, of the display information  103 . Thus, the one or more filters  115  may include any filter or combination of filters or other optical components capable of substantially blocking the display information  103  while substantially transmitting the non-display information  105 . 
     Optical power is the degree to which a lens or mirror converges or diverges light or electromagnetic radiation. A lens or mirror having substantially zero optical power neither converges nor diverges electromagnetic radiation. Normal power is the power necessary to provide correction in an optical system, such as a human visual system, for defects in the optical system. For example, normal power includes a power to correct for nearsightedness, farsightedness, or astigmatism in a human visual system. In some embodiments, a normal power is between about 0.25 and about 10 diopters. 
     Close power is the power necessary to provide correction in an optical system, such as a human visual system, for viewing at a close distance. In a human visual system, a close distance is a distance of less than about 250 millimeters. For objects closer than about 250 millimeters, the human visual system cannot form a sharp image on the retina. A focusing lens can provide close power to assist a human visual system in viewing objects at distances of less than about 250 millimeters. In some embodiments, the close power is between about 5 and about 200 diopters. 
     In some embodiments, the apparatus  101  includes combinations of optical powers. In some embodiments, the display information path optical power  113  includes substantially zero power and the non-display information path optical power  117  includes substantially zero power. In other embodiments, the display information path optical power  113  includes substantially zero power and the non-display information path optical power  117  includes a normal power. In further embodiments, the display information path optical power  113  includes a close power and the non-display information path optical power  117  includes substantially zero power. In additional embodiments, the display information path optical power  113  includes a close power and the non-display information path optical power  117  includes normal power. 
       FIG.  1 B  shows a block diagram of the apparatus  101  (shown in  FIG.  1 A ) coupled to a human visual system  131  in accordance with some embodiments. The apparatus  101  (dashed lines) includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes the one or more filters  115  and the non-display information path optical power  117 . 
     In some embodiments, the display information optical path  109  has an aperture  119 . The aperture  119  may be sized to assist in focusing the display information  103 . In some embodiments, the aperture  119  is sized to increase the depth of focus in the display information optical path  109 . In some embodiments, the aperture  119  has a diameter of about one millimeter. 
     In operation, the display information optical path  109  and the non-display information optical path  111  assist the human visual system  131  in forming a focused image of the display information  103  and a focused image of the non-display information  105  on a retina  133 . The display information optical path  109  in cooperation with the human visual system  131 , including the human lens  134 , substantially focuses the display information  103  to the retina  133  to form retinal display information image  135 . The non-display information optical path  111  in cooperation with the human visual system  131 , including the human lens  134 , substantially focuses the non-display information  105  to the retina  133  to form retinal non-display information image  137 . At least one of the one or more filters  115  in the non-display information optical path  111  substantially blocks the display information  103  from entering the human visual system  131  from the non-display information optical path  111 . 
       FIG.  1 C  shows a block diagram of an apparatus  141  including the apparatus  101  (shown in  FIG.  1 A ), and further including a display  143  to provide the display information  103  in accordance with some embodiments. The apparatus  101  (dashed lines) includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes the one or more filters  115  and the non-display information path optical power  117 . 
     In some embodiments, the display information  103  includes information provided by the display  143 . The display  143  includes any device or system that provides information in the form of electromagnetic radiation, such as visible light. For example, in some embodiments, the display information  103  is provided by a device including a single two-state source of visible light. 
     The display  143  is not limited to a particular type of display. In some embodiments, the display  143  includes micro-displays and other small displays, such as displays having a thickness of between about 100 microns and about two millimeters, flat screen displays, such as liquid crystal displays, and cathode ray tube displays. In some embodiments, the display  143  is mounted in an eyeglass frame. In operation, in some embodiments, the distance between the display and a human cornea is between about 5 millimeters and about 200 millimeters. 
     The display information  103  provided by the display  143  may include a characteristic feature related to the wavelength of the display information  103 . In some embodiments, the display information  103  provided by the display  143  includes information having a narrow spectral bandwidth. Exemplary displays that provide the display information  103  having a narrow spectral bandwidth include organic light emitting diode displays and electroluminescent displays. 
     The display  143  is not limited to providing the display information  103 . In some embodiments, the display  143  is substantially occluded, partially occluded, or substantially transparent. For a partially occluded or substantially transparent display, the display  143  may transmit the non-display information  105  in addition to providing the display information  103 . An organic light emitting diode display is an exemplary display capable of providing substantially transparent, partially occluded, and substantially occluded operation. 
       FIG.  1 D  shows a block diagram of an apparatus  151  including the apparatus  101  (shown in  FIG.  1 A ), wherein at least one of the one or more filters  115  includes a non-display path notch filter  153  or a non-display path polarizing filter  155  and further including the display  143  to provide the display information  103  in accordance with some embodiments. The apparatus  101  (dashed lines) includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes the one or more filters  115  and the non-display information path optical power  117 . In some embodiments, the display information optical path includes a display path bandpass filter  157 . In other embodiments, the display information optical path includes a display path polarizing filter  159 . 
     The non-display path notch filter  153  is selected to substantially block the display information  103  in the non-display information optical path  111 . In some embodiments, the non-display path notch filter  153  is selected to block at least about 90% of the energy included in the display information  103 . Blocking less than about 90% of energy included in the display information  103  may result in blurring of the display information  103  and the non-display information  105 . The non-display path notch filter  153  is not limited to a particular type of notch filter. In some embodiments, the non-display path notch filter  153  includes a thin film interference filter, such as a rugate filter. Notch filters, such as the non-display path notch filter  153 , are formed by periodically varying the refractive index in each of a plurality of discrete thin film layers included in a contact lens. Microlithographic processes can be applied to each of the plurality of discrete thin film layers to pattern the notch filters. The plurality of discrete thin film layers may be introduced into the contact lens during the molding of the lens. 
     In operation, the non-display path notch filter  153  is included in the non-display information optical path  111  to block narrow bandwidth electromagnetic radiation included in the display information  103 . If the non-display information  105  includes broad spectral bandwidth electromagnetic radiation, the non-display path notch filter  153  has substantially no effect on the non-display information  105 . The non-display information  105  passes through the non-display information optical path  111  substantially unchanged. 
     In some embodiments, the frequencies to be blocked by the non-display path notch filter  153  include the primary colors included in the spectrum of the display information  103 . For example, for the display information  103  having primary colors red, green, and blue, the one or more filters  115  are selected to substantially block narrow spectrum red, green, and blue. The transmission curve to substantially block narrow spectrum red, green, and blue includes “notches” or a transmission coefficient of substantially zero at the one or more bands of frequencies to be blocked, narrow spectrum red, green, and blue. In some embodiments, the “notches” have a bandwidth that blocks a band of frequencies, such as, for example, a band of frequencies having a narrow spectrum of between about two and about thirty nanometers, centered on each of the primary colors, red, green, and blue. 
     The non-display path polarizing filter  155  is selected to substantially block the display information  103  in the non-display information optical path  111 . The non-display path polarizing filter  155  is not limited to a particular type of polarizing filter. In some embodiments, the non-display path polarizing filter  155  includes a filter to substantially block right-handed circularly polarized radiation. In other embodiments, the non-display path polarizing filter  155  is selected to substantially block left-handed circularly polarized electromagnetic radiation. In further embodiments, the non-display path polarizing filter  155  is selected to substantially block linearly polarized electromagnetic radiation. Pixelated micro-wires and birefringent polymers are suitable for use in forming linear polarizers for use in forming polarizing filters, such as the non-display path polarizing filter  155 . Circular polarizers are formed by adding a quarter wave-plate retarder in series with a linear polarizer. 
     In operation, the non-display path polarizing filter  155  is included in the non-display information optical path  111  to block polarized electromagnetic radiation included in the display information  103 . For example, if the display information  103  includes left-handed circularly polarized electromagnetic radiation and the non-display information  105  includes right-handed circularly polarized electromagnetic radiation, the non-display path polarizing filter  155  is selected to substantially block the left-handed circularly polarized electromagnetic radiation while having substantially no effect on the right-handed circularly polarized electromagnetic radiation of the non-display information  105 . The non-display information  105  passes through the non-display information optical path  111  substantially unchanged. 
     The display path bandpass filter  157  is selected to substantially block the non-display information  105  in the display information optical path  109 . The display path bandpass filter  157  is not limited to a particular type of bandpass filter. In some embodiments, the display path bandpass filter  157  includes a thin film interference filter, such as a rugate filter. Bandpass filters, such as the display path bandpass filter  157 , are formed by varying the refractive index in each of a plurality of thin films to selectively pass the desired wavelength bands and including the plurality of discrete thin film layers in a contact lens. Microlithographic processes can be applied to the plurality of thin films to pattern the bandpass filters. The plurality of discrete thin film layers may be introduced into the contact lens during the molding of the lens. 
     In operation, the display path bandpass filter  157  included in the display information optical path  109  is selected to substantially block broad spectral bandwidth electromagnetic radiation included in the non-display information  105 . If the display information  103  includes narrow spectral bandwidth electromagnetic radiation substantially matched to the passband of the display path bandpass filter  157 , the display path bandpass filter  157  has substantially no effect on the display information  103 . The display information  103  passes through the display information optical path  109  substantially unchanged. 
     The display path polarizing filter  159  is selected to substantially block the non-display information  105  in the display information optical path  109 . The display path polarizing filter  159  is not limited to a particular type of polarizing filter. In some embodiments, the display path polarizing filter  159  includes a linearly polarized filter. 
     In operation, the display path polarizing filter  159  is included in the display information optical path  109  to substantially block electromagnetic radiation included in the non-display information  105 . If the display information  103  includes right-handed circularly polarized electromagnetic radiation and the display path polarizing filter  159  is selected to transmit right-handed circularly polarized electromagnetic radiation, the display path polarizing filter  159  has substantially no effect on the display information  103 . The display information  103  passes through the display information optical path  109  substantially unchanged. 
     In some embodiments, in operation the apparatus  151  processes a combination of spectral bandwidths and polarizations in the display information  103  and the non-display information  105 . In some embodiments, the display information  103  includes display electromagnetic radiation having a narrow spectral bandwidth and the non-display information  105  includes non-display electromagnetic radiation having a broad spectral bandwidth. In other embodiments, the display information  103  includes display electromagnetic radiation having a display information polarization and the non-display information  105  includes non-display electromagnetic radiation having a non-display information polarization. In further embodiments, the display information  103  includes display electromagnetic radiation having a narrow spectral bandwidth and a display information polarization and the non-display information  105  includes non-display electromagnetic radiation having a broad spectral bandwidth. In additional embodiments, the display information  103  includes display information including display electromagnetic radiation having a narrow spectral bandwidth and a display information polarization and the non-display information  105  including non-display electromagnetic radiation having a broad spectral bandwidth and a non-display information polarization. 
       FIG.  1 E  shows a block diagram of an apparatus  161  including the apparatus  101  (shown in  FIG.  1 A ), wherein the one or more filters  115  includes the non-display path polarizing filter  155  (shown in  FIG.  1 D ) and further including the display  143  (shown in  FIG.  1 C  in accordance with some embodiments The apparatus  101  includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes the one or more filters  115  and the non-display information path optical power  117 . The display information  103  includes electromagnetic radiation having a display information polarization. The non-display information  105  includes non-display electromagnetic radiation having a non-display information polarization. 
     The non-display path polarizing filter  155  is selected to block the display information  103 . In some embodiments, the display information  103  includes electromagnetic radiation having the display information polarization. To block the display information  103 , the non-display path polarizing filter  155  is selected to block electromagnetic radiation having the display information polarization. In some embodiments, the non-display information  105  includes the non-display electromagnetic radiation having the non-display information polarization. The non-display path polarizing filter  155  is selected to pass the non-display electromagnetic radiation having the non-display information polarization. 
       FIG.  2 A  shows a block diagram of an apparatus  201  to receive and process the display information  103  and the non-display information  105  in accordance with some embodiments. The apparatus  201  includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . 
     The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes one or more controllable optical materials  203  and the non-display information path optical power  117 . 
     The one or more controllable optical materials  203  include materials having one or more controllable optical properties. In some embodiments, the one or more controllable optical materials  203  include photochromic materials. The controllable optical properties, such as opacity, may be controlled by providing the photochromic material with an electromagnetic signal, such as an optical signal, for example, to increase or decrease the opacity of the photochromic material. 
     In some embodiments, the one or more controllable optical materials  203  include an electrochromic material. The one or more controllable optical properties, such as opacity, may be controlled by providing the electrochromic material with an electromagnetic signal, such as a radio frequency signal, for example, to increase or decrease the opacity of the electrochromic material. 
     In operation, the one or more controllable optical materials  203  included in the non-display information optical path  111  block or transmit information in the non-display information optical path  111 . When at least one of the one or more controllable optical materials  203  is set to block information in the non-display information optical path  111 . substantially only display information  103  in the display information optical path  109  passes through the substrate  107 . 
     Neither the display information path optical power  113  nor the non-display information path optical power  117  is limited to a particular power. In some embodiments, the apparatus  201  includes a combination of optical powers. In some embodiments, the display information path optical power  113  includes substantially zero power and the non-display information path optical path power  117  includes substantially zero power. In other embodiments, the display information path optical power  113  includes substantially zero power and the non-display information path optical power  117  includes a normal power. In further embodiments, the display information path optical power  113  includes a close power and the non-display information path optical power  117  includes substantially zero power. In additional embodiments, the display information path optical power  113  includes a close power and the non-display information path optical power  117  includes normal power. 
       FIG.  2 B  shows a block diagram of the apparatus  201  (shown in  FIG.  2 A ) coupled to the human visual system  131  in accordance with some embodiments. The apparatus  201  (dashed lines) includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes the one or more controllable optical materials  203  and the non-display information path optical power  117 . 
     In some embodiments, the display information optical path  109  has an aperture  119 . The aperture  119  may be sized to assist in focusing the display information  103 . In some embodiments, the aperture  119  is sized to increase the depth of focus in the display information optical path  109 . In some embodiments, the aperture  119  has a diameter of about one millimeter. 
     In operation, the display information optical path  109  and the non-display information optical path  111  assist the human visual system  131  in forming a focused image of the display information  103  at the retina  133  and a focused image of the non-display information  105  at the retina  133 . The display information optical path  109  in cooperation with the human visual system  131 , including the human lens  134 , substantially focuses the display information  103  at the retina  133  to form a retinal display information image  135 . The non-display information optical path  111  in cooperation with the human visual system  131 , including the human lens  134 , substantially focuses the non-display information  105  at the retina  133  to form a retinal non-display information image  137 . At least one of the one or more controllable optical materials  203  in the non-display information optical path  111  substantially blocks the display information  103  from entering the human visual system  131  from the non-display information optical path  111 . 
       FIG.  2 C  shows a block diagram of an apparatus  211  including the apparatus  201  (shown in  FIG.  2 A ), and further including the display  143  (shown in  FIG.  1 C ) to provide the display information  103  in accordance with some embodiments. The apparatus  201  (dashed lines) includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . The non-display information optical path  111  includes the one or more controllable optical materials  203  and the non-display information path optical power  117 . In some embodiments, the display information  103  includes information provided by the display  143 . 
       FIG.  2 D  shows a block diagram of an apparatus  221  including the apparatus  201  (shown in  FIG.  2 A ), wherein at least one of the one or more controllable optical materials  203  includes a photochromic material  223  or an electrochromic material  225  and further including the display  143  to provide the display information  103  and one or more optical material activation signals  227  in accordance with some embodiments. The apparatus  201  (dashed lines) includes the substrate  107  including the display information optical path  109  to receive the display information  103  and including the non-display information optical path  111  to receive the non-display information  105 . The display information optical path  109  includes the display information path optical power  113 . 
     The non-display information optical path  111  includes the one more controllable optical materials  203  and the non-display information path optical power  117 . In some embodiments, the display information optical path  109  includes the display path bandpass filter  157 . In some embodiments, the display information optical path  109  includes the display path polarizing filter  159 . 
     The one or more material activation signals  227  provide control information to the one or more controllable optical materials  203 . In some embodiments, the one or more material activation signals  227  provide control information to the photochromic material  223 . An optical signal is an exemplary signal suitable for use in providing control information to the photochromic material  223 . In some embodiments, the one or more material activation signals  227  provide control information to the electrochromic material  225 . A radio frequency signal is an exemplary signal suitable for use in providing control information to the electrochromic material  225 . In some embodiments, the one or more material activation signals  227  are provided by the display  143 . 
     In operation, one or more of the photochromic material  223  and the electrochromic material  225  are included in the non-display information optical path  111  to block or transmit information in the non-display information optical path  111 . When at least one of the one or more of the photochromic material  223  and the electrochromic material  225  is set to block information in the non-display information optical path  111 , substantially only display information  103  in the display information optical path  109  passes through the substrate  107 . 
       FIG.  3    shows an apparatus  301  comprising a substrate  303  including an optical path  305  having one or more zone plates  307  to receive the display information  103  and the non-display information  105  in accordance with some embodiments. 
     The substrate  303  is not limited to being formed from a particular material or combination of materials. Any materials suitable for use in forming optical components, such as lenses, may be used in forming the substrate  303 . Exemplary materials suitable for use in forming the substrate  303  include gels such as silicone hydrogels, glasses, plastics, and polymers such as polymethyl, methacrylate and polymacon. The substrate  303  is not limited to a particular type of optical component. In some embodiments, the substrate  303  includes a lens, such as a contact lens, formed from one or more of the exemplary materials. 
     The formation of the one or more zone plates  307  is not limited to a particular process or set of processes. In some embodiments, each of the one or more zone plates  307  is formed by patterning an interference filter, such as a rugate filter, in concentric rings in one of the one or more zone plates  307 . The patterning of a rugate filter is not limited to a particular type of patterning. In some embodiments, the patterning includes binary patterning. In other embodiments, the patterning includes sinusoidal patterning. The refractive index of the rugate filter may vary continuously and periodically. 
     The one or more zone plates  307 , in some embodiments, include three zone plates stacked substantially one on top of the other in the optical path  305  included in the substrate  303 . In some embodiments, a display that provides the display information  103  includes the primary colors red, green, and blue and the one or more zone plates  307  are selected to filter the primary colors. To filter the colors red, green, and blue, one of the one or more zone plates  307  may include a rugate filter formed to filter the color red. A second of the one or more zone plates  307  may include a rugate filter formed to filter the color green, while a third of the one or more zone plates  307  may include a rugate filter formed to filter the color blue. The rugate filter formed to filter the color red includes rings that block red and rings that pass all other colors. The rugate filter formed to filter the color green includes rings that block green and rings that pass all other colors, whereas the rugate filter formed to filter the color blue includes rings that block blue and rings that pass all other colors. 
     In some embodiments, the display information  103  is substantially collimated by the one or more zone plates  307 . To collimate the display information  103 , the one or more zone plates  307  are formed to have a focal length of between about five and about two hundred millimeters. 
     In operation, the apparatus  301  processes the display information  103  and the non-display information  105  substantially simultaneously. The display information  103  is diffracted and substantially focused as the display information  103  passes through the optical path  305 . The non-display information  105  passes through the optical path  305  substantially unchanged. The display information  103  and the non-display information  105  are focused to substantially the same focal point at substantially the same time. For a focal point located at a retina of a human visual system, the brain superimposes the two images. 
     The apparatus  301 , in some embodiments, includes a display  309 . In some embodiments, the display  309  provides display information  103  including display electromagnetic radiation having at least one characteristic feature. The non-display information  105  includes non-display electromagnetic radiation lacking the at least one characteristic feature. In some embodiments, the display  309  provides the display information  103  including display electromagnetic radiation having a narrow spectral bandwidth. The non-display information  105  includes non-display electromagnetic radiation having a broad spectral bandwidth. In some embodiments, the display  309  provides the display information  103  including display electromagnetic radiation having a display information polarization. The non-display information  105  includes non-display electromagnetic radiation having a non-display information polarization different from the display information polarization. 
     The optical path  305  is not limited to a particular optical power. In some embodiments, the optical path  305  provides substantially zero optical power  313  for the non-display information  103 . In some embodiments, the optical path  305  provides a normal optical power  315  for the non-display information  105 . 
     In some embodiments, the apparatus  301  includes a filter  317  substantially surrounding around the optical path  305 . In some embodiments, when the apparatus  301  is used in combination with a human visual system, the filter  317  includes a substantially opaque filter to substantially block the display information  103  outside the optical path  305  from entering the human visual system. In some embodiments, when the apparatus  301  is used in combination with a human visual system, the filter  317  includes a non-display path polarizing filter to substantially block the display information  103  outside the optical path  305  from entering the human visual system. In some embodiments, when the apparatus  301  is used in combination with a human visual system, the filter  317  includes a notch filter to substantially block the display information  103  outside the optical path  305  from entering the human visual system. 
       FIGS.  4 A and  4 B  (diametrical section of contact lens  401  shown in 4A) show illustrations of a contact lens  401  including the display information optical path  109  and the non-display information optical path  111  in accordance with some embodiments. The display information optical path  109  forms a substantially cylindrical path through a central area-of the contact lens  401 . The diameter of the display information optical path  109  may be sized to increase the depth of focus and thereby assist in focusing light from a display, such as a head-mounted display, to a retina in a wearer’s visual system. In some embodiments, the display information optical path  109  includes a focusing element  403 . such as a lens, to assist the wearer’s visual system in focusing light rays to the retina. In some embodiments, the display information optical path  109  includes a wavelength selective filter, a polarization selective filter, or a variable opacity filter including one or more controllable optical materials such as electrochromic or photochromic materials. 
     The non-display information optical path  111  forms a substantially annular ring surrounding the display information optical path  109 . The non-display information optical path  111  may also include a non-display information path optical power to assist the wearer’s visual system in focusing light rays from objects located at a greater distance from the wearer’s visual system than the display. The non-display information path optical power assists the wearer’s visual system by providing an appropriate power to correct for deficiencies in the wearer’s visual system. For example, for a nearsighted wearer, the non-display information optical path  111  may include an optical power to correct for the wearer’s nearsightedness and permit the nearsighted wearer to clearly view objects more distant from the wearer’s visual system than the display. In some embodiments, the non-display information optical path  111  includes (i) a wavelength selective filter (including a wavelength selectivity different from the selectivity of the wavelength selective filter of the display information optical path  109 ), (ii) a polarization selective filter (including a polarization selectivity different from the polarization selectivity of the polarization selective filter of the display information optical path  109 ), or (iii) a variable opacity filter. 
     In operation, the contact lens  401  substantially conforms to the shape of a wearer’s cornea. The display information optical path  109  receives and passes or transmits light rays from the display to the wearer. The non-display information optical path  111  receives and passes or transmits light rays from objects more distant from the wearer’s visual system than the display. 
       FIG.  5    shows an illustration of the display  143  optically coupled by the contact lens  401  to the human visual system  131  to illustrate processing non-display information using wavelength filters in accordance with some embodiments. In the illustrated embodiment, the display  143  includes a display notch filter  501  and an organic light emitting diode display  503 . In some embodiments, the contact lens  401  includes (i) display path bandpass filter  157 , such as a narrow band bandpass filter, (ii) focusing element  505  to provide display information path optical power, and (iii) one or more filters  115 , such as one or more notch filters. The human visual system  131  includes an iris  507 , the human lens  134 , and the retina  133 . 
     In operation, the light rays  509  received from objects more distant from the contact lens  401  than the display  143  encounter the display  143 , the contact lens  401 , and the human visual system  131 . At the display  143 , the display notch filter  501  filters the light rays  509 . The wavelengths of the light rays  509  that correspond to the wavelength notches of display notch filter  501  are substantially removed by the display notch filter  501 , allowing light rays  511  to pass. The light rays  511  pass through the display  143  substantially unaltered. At the contact lens  401 , the light rays  511  are substantially blocked by the display path bandpass filter  157  and substantially passed by the one or more filters  115 . At the human visual system  131 . one or more of the light rays  511  pass through the iris  507  to form light rays  513 . The human lens  134  focuses the light rays  513  to the retina  133 . 
     Shadow  515  is created by the light rays blocked by the display path bandpass filter  157 . The display path bandpass filter  157  slightly reduces the image intensity at the retina  133  when compared to an image formed at the retina  133  in the absence of the display path bandpass filter  157 . Otherwise, the image at the retina  133  is substantially unaltered by the display path bandpass filter  157 . The focusing element  505  has substantially no affect on the light rays  513  reaching the retina  133 , as the light rays  511  received at the focusing element  505  are blocked by the display path bandpass filter  157 . 
     In the absence of the display  143 , a wearer of the contact lens  401  sees a normal; real world environment except that the light rays  511  now include the wavelengths substantially blocked by the display notch filter  501  when the display  143  is in use. At the contact lens  401 , the wavelengths blocked at the display notch filter  501  when the display  143  is in use are passed by the display path bandpass filter  157  and defocused by the focusing element  505 . 
       FIG.  6    shows an illustration of the display  143  optically coupled by the contact lens  401  to the human visual system  131  to illustrate processing display information using wavelength filters in accordance with some embodiments. The display  143  includes the display notch filter  501  and the organic light emitting diode display  503 . The contact lens  401  includes (i) the display path bandpass filter  157 , such as a narrow bandwidth bandpass filter, (ii) the focusing element  505  to provide display information path optical power, and (iii) the one or more filters  115 . The human visual system  131  includes the iris  507 . the human lens  134 , and the retina  133 . 
     In operation, light rays  601  and  602  are provided by the organic light emitting diode display  503 . The light rays  602  are blocked by the display notch filter  501 . Thus, the light rays  602  are not visible to a viewer looking at a wearer of the contact lens  401 . The light rays  601  are received at the contact lens  401  and the human visual system  131 . The light rays  601  are blocked by the one or more filters  115 , for example, a notch filter, but are passed as light rays  603  by the display path bandpass filter  157 . The focusing element  505 , such as a focusing lens, provides optical power to assist the human lens  134  to focus the light rays  603  to the retina  133 . The light rays  603  are substantially unaffected by the iris  507 . 
     In some embodiments, the display  143  is occluded or partially occluded. In such embodiments, a material having an opacity is included in the display  143  to provide the occlusion or partial occlusion. When the material is included in the display  143  on the side of display  143  facing away from the contact lens  401 , some or all of the non-display information or ambient light rays are blocked. In such embodiments, the display notch filter  501  is not required. 
       FIG.  7    shows an illustration of the display  143  optically coupled by the contact lens  401  to the human visual system  131  to illustrate processing to combine non-display information and display information using wavelength filters in accordance with some embodiments. The display  143  includes the display notch filter  501  and the organic light emitting diode display  503 . The contact lens  401  includes the display path bandpass filter  157 , the focusing element  505  to provide display information path optical power, and the one or more filters  115 . The human visual system  131  includes the iris  507 , the human lens  134 , and the retina  133 . 
     In operation, the light rays  509  received from objects more distant from the contact lens  401  than the display  143  are processed as described above in the description of  FIG.  5    to provide light rays  511  and  513 . The light rays  601  and  602  provided by the display  143  are processed as described above in the description of  FIG.  6    to provide light rays  603 . The light rays  603  come to a focus at substantially the same spot on the retina  133  as the light rays  513 . The wearer’s brain combines the retinal images provided by the light rays  603  and the light rays  509  to form a superimposed image. 
       FIG.  8    shows an illustration of the display  143  optically coupled by the contact lens  401  to the human visual system  131  to illustrate processing non-display information using polarizing filters in accordance with some embodiments. The display  143  includes the organic light emitting diode display  503 . a display polarizing filter  801 , and display shutters  803  and  805 . The contact lens  401  includes a display path filter  807 . such as a display path bandpass filter or a display path polarizing filter, the focusing element  505  to provide display information path optical power, and the non-display path polarizing filter  155 . The human visual system  131  includes the iris  507 , the human lens  134 , and the retina  133 . 
     In operation, the light rays  809  are polarized by the display polarizing filter  801  to form light rays  811 . The shutters  803  and  805  are switched to the same polarization as the display polarizing filter  801 . Thus, the light rays  811  pass through the shutters  803  and  805  substantially unaltered. The organic light emitting diode display  503  is set to an “off” state and is therefore substantially translucent to the light rays  811 . Thus, the light rays  811  also pass through the organic light emitting diode display  503  substantially unaltered. The light rays  811  are substantially blocked by the display path filter  807 . In some embodiments, the display path filter  807  includes the display path bandpass filter  157  (shown in  FIG.  1 D ). In some embodiments, the display path filter  807  includes the display path polarizing filter  159  (shown in  FIG.  1 D ) having a polarization different from the polarization of the shutters  803  and  805 . The non-display path polarizing filter  155  has the same polarization as the shutters  803  and  805 . Thus, the light rays  811  pass through the non-display path polarizing filter  155  substantially unaltered. At the human visual system  131 , the iris  507  limits the light rays passing through the iris  507  to light rays  813 . The human lens  134  focuses the light rays  813  at the retina  133 . 
     Shadow  815  is created by the light rays blocked by the display path filter  807 . The display path filter  807  slightly reduces the image intensity at the retina  133  when compared to an image formed at the retina  133  in the absence of the display path filter  807 . Otherwise, the image at the retina  133  is substantially unaltered by the display path filter  807 . The focusing element  505  has substantially no affect on the light rays  811  reaching the retina  133 , as the light rays  811  passing through the focusing element  505  are substantially blocked by the display path filter  807 . 
     In the absence of the display  143 , a wearer of the contact lens  401  sees a normal, real world environment except that the light rays  811  are polarized. For the display path filter  807   including either a polarizing filter or a bandpass filter, the light rays passing through the display path filter  807  are defocused by the focusing element  505  before reaching retina  133 . 
       FIG.  9    shows an illustration of the display  143  optically coupled by the contact lens  401  to the human visual system  131  to illustrate processing display information using polarizing filters in accordance with some embodiments. The display  143  includes the display polarizing filter  801 , the display shutter  803 , the organic light emitting diode display  503 , and the display shutter  805 . The contact lens  401  includes the non-display path polarizing filter  155 , the display path filter  807 , such as a display path bandpass filter or a display path polarizing filter, and the focusing element  505  to provide display information path optical power. The human visual system  131  includes the iris  507 , the human lens  134 , and the retina.  133 . 
     In operation, the display polarizing filter  801  polarizes the light rays  809  to form light rays  811 . The shutter  803  is switched to a polarization to substantially block the light rays  811 , and the organic light emitting diode display  503  is set to an “on” state. The organic light emitting diode display  503  provides the light rays  601  and  602 , while the shutter  803  polarizes the light rays  602  to form light rays  901 . The display polarizing filter  801  is set to a polarization to substantially block the light rays  901 . Thus, the light rays  901  are not visible to a viewer looking at a wearer of the display  143 . The shutter  805  polarizes the light rays  601  to form light rays  903 . The non-display path polarizing filter  155  is set to a polarization to substantially block the light rays  903 . For the display path filter  807  set to substantially the same polarization as the shutter  805 , the display path filter  807  passes the light rays  903  substantially unaltered. The focusing element  505 . such as a focusing lens, provides optical power to assist the human lens  134  to focus the light rays  905  to the retina  133 . Thus, the focusing element  505  may provide an optical power to assist the human lens  134  in focusing the light rays  903  at the retina  133 . The human lens  134  in combination with the focusing element  505  processes the light rays  903  to form light rays  905 . The iris  507  has substantially no affect on the light rays  905  substantially focused at the retina  133 . 
     If the display  143  is occluded or partially occluded, the display polarization filter  801  is not required. Instead, in some embodiments, a material having an opacity is included on the side of the display  143  facing away from the contact lens  401  to block some or all of the light rays  509  including the non-display information. 
     In some embodiments, a quarter wave-plate is included in the shutter  805  to convert the light rays  601  having a linear polarization to a circular polarization. To support the processing of circularly polarized radiation, the non-display path polarizing filter  155  includes a filter to provide transmission of right-handed circularly polarized radiation. Also, to support the processing of circularly polarized radiation, the display path filter  807  includes a filter to provide transmission of left-handed circularly polarized radiation. In operation, to process the non-display information, the shutter  805  including the quarter wave-plate is set to pass right-handed circularly polarized radiation. In operation, to process the display information the shutter  805  including the quarter wave plate is set to pass left-handed circularly polarized radiation. In some embodiments, the display path filter  807  includes a display path bandpass filter. 
     A filter providing transmission of circularly polarized radiation, unlike a filter providing for transmission of linearly polarized radiation, does not require rotational alignment of the contact lens  401  with the human visual system  131 . However, the non-display path polarizing filter  155  is not limited to a filter for processing circularly polarized radiation. In some embodiments, the non-display path polarizing filter  155  includes a filter to provide transmission of linearly polarized radiation. 
     Referring to  FIG.  8    and  FIG.  9   , in some embodiments the shutters  803  and  805  are switched between one polarization state and another polarization state in synchronization with the setting of the organic light emitting diode display  503  to an “on” state and an “off” state. For example, when the organic light emitting diode display  503  is set to an “on” state, the shutters  803  and  805  are switched to the state as described for  FIG.  9    to process the display information provided by the light rays  601  and  602  from the organic light emitting diode display  503 . And, for example, when the organic light emitting diode display  503  is set to an “off” state, the shutters  803  and  805  are switched to the state as described for  FIG.  8    to process non-display information provided by the light rays  809 . The switching rate is set to a frequency that allows the brain of a wearer of the contact lens  401  to form a single image from the superposition of the images of the display information and the non-display information. 
     Polarizing shutters, such as shutters  803  and  805 , can utilize liquid crystal display panels that re-orient their liquid crystals in response to an applied electric field. When the crystals are oriented in one direction, they pass electromagnetic radiation having a particular polarization. Changing the electric field to orient the crystals in a second direction causes electromagnetic radiation having a second polarization to be passed. 
       FIGS.  10 A and  10 B  (diametrical section of illustration shown in IOA) show illustrations of a contact lens  1001  including one or more zone plate filters  1003  in accordance with some embodiments. In certain embodiments, the one or more zone plate filters  1003  are formed by patterning a rugate filter in concentric rings of a diffraction zone plate, which focuses light using diffraction to cause constructive interference at a focal point to create an image. A rugate filter includes optical interference films of varying thickness. The refractive index of the optical interference film varies as a function of the film’s optical thickness. The use of a rugate filter in forming a zone plate results in a zone plate that operates on a particular set of wavelengths, for example, a narrow band of wavelengths. In some embodiments, the patterning of the zone plate is binary. Binary patterning includes substantially opaque and transparent rings of substantially equal areas. In some embodiments, the patterning is sinusoid. Sinusoid patterning includes rings having substantially gradual variations in opacity. In some embodiments, the contact lens  1001  includes a notch filter  1005  forming substantially an annular ring around the one or more zone plate filters  1003 . 
       FIG.  11    shows an illustration of the display  143  optically coupled by the contact lens  1001  to the human visual system  131  to illustrate processing display information and non-display information using the one or more zone plate filters  1003  in accordance with some embodiments. The display  143  includes the display notch filter  501  and the organic light emitting diode display  503 . The contact lens  1001  includes the one or more zone plate filters  1003 . In some embodiments, the contact lens  1001  includes the notch filter  1005 . The human visual system  131  includes the iris  507 , the human lens  134 , and the retina  133 . 
     In operation, the light rays  509  providing non-display information received from objects more distant from the contact lens  1001  than the display  143  encounter the display  143 , the contact lens  1001 , and the human visual system  131 . At the display  143 , the display notch filter  501  filters the light rays  509 . The wavelengths of the light rays  509  that correspond to the wavelength notches of the display notch filter  501  are substantially removed by the display notch filter  501 , passing the light rays  511 . The light rays  511  pass through the display  143  substantially unaltered. At the contact lens  1001 , the light rays  511  pass through the one or more zone plate filters  1003  and the notch filter  1005  substantially unaltered. At the human visual system  131 , the iris  507  may block some of the light rays  511 , passing light rays  1007 . The human lens  134  focuses the light rays  1007  including the non-display information at the retina  133 . 
     In operation, the organic light emitting diode display  503  provides light rays  601  and  602 . The light rays  602  are directed away from the contact lens  1001  and are substantially blocked by the display notch filter  501 . Thus, the light rays  602  are not visible to a viewer looking at a wearer of the display  143 . The light rays  601  are directed toward the contact lens  1001  including the notch filter  1005  and the one or more zone plate filters  1003 . At the notch filter  1005 . the light rays  601  are substantially blocked. At the one or more zone plate filters  1003 , the light rays  601  are diffracted to form the light rays  1009 . The human lens  134  focuses the light rays  1009  including the display information at the retina  133 . 
     In operation, the light rays  509  received from objects more distant from the contact lens  1001  than the display  143  are processed as described above to provide the light rays  1007  including the non-display information to the retina  133 . The light rays  601  provided by the display  143  are processed as described above to provide the light rays  1009  including the display information to the retina  133 . The light rays  1007  and the light rays  1009  are focused at substantially the same spot at the retina  133  at substantially the same time. Thus, the brain of the wearer of the contact lens  1001  combines the retinal image provided by the light rays  1007  including the non-display information and the retinal image provided by the light rays  1009  including the display information to form a superimposed image including the display information and the non-display information. 
     In the absence of the display  143 , a wearer of the contact lens  1001  sees a normal, real world environment except the light rays  511  now include the wavelengths substantially blocked by the display notch filter  501 . At the contact lens  1001 , the wavelengths blocked at the display notch filter  501  when the display  143  is present are diffracted by the one or more zone plate filters  1003  and defocused by the human lens  134 . 
     If the display  143  is occluded or partially occluded, the display notch filter  501  is not required. Instead, in some embodiments, a material having an opacity is included on the side of the display  143  facing away from the contact lens  1001  to block some or all of the light rays  509  including the non-display information. 
       FIG.  12    shows an illustration of an apparatus  1201  including a substrate  1203 . a substantially transparent pixel unit  1205 , and an organic light emitting diode unit  1207  in accordance with some embodiments. The substrate  1203  includes a pattern  1209  of pixel sites including a first pattern of one or more first pixel sites  1211  and a second pattern of one or more second pixel sites  1213 . The substantially transparent pixel unit  1205  is located at substantially each of the one or more first pixel sites  1211 . The organic light emitting diode pixel unit  1207  including a filter  1215  is located at substantially each of the one or more second pixel sites  1213 . The filter  1215  is located on the substrate  1203  to enable filtering of the electromagnetic radiation emitted by the organic light emitting diode unit before the electromagnetic radiation reaches a viewer. To filter the electromagnetic radiation, such as visible light, emitted by the organic light emitting diode pixel unit  1207 , the area of the filter  1215  is substantially equal to or greater than the area of the organic light emitting diode pixel unit  1207 . In some embodiments, the filter  1215  is a narrow band filter. In other embodiments, the filter  1215  is a polarizing filter. The pattern  1209  of pixel sites is not limited to a particular pattern. In some embodiments, the pattern  1209  of pixel sites includes a checkerboard pattern including the first pattern of the one or more first pixel sites  1211  alternating with the second pattern of the one or more second pixel sites  1213 . The sites are not limited to a particular shape and the shapes shown are only for schematic illustration. 
       FIG.  13    shows a flow diagram of a method  1301  including enabling and disabling transmission of display information and transmission of non-display information in accordance with some embodiments. In the illustrated embodiment, the method  1301  enables transmission of display information from a display and switches one or more shutters to a first polarization to polarize the display information (block  1303 ), and disables transmission of the display information from the display and switches the one or more shutters to a second polarization different from the first polarization to enable transmission of the non-display information through the one or more shutters (block  1305 ). In some embodiments, the method  1301  includes receiving the display information and the non-display information at a contact lens. In some embodiments, the method  1301  includes substantially blocking the display information at a non-display information optical path included in the contact lens and substantially transmitting the display information at a display information optical path included in the contact lens. 
       FIG.  14    shows a flow diagram of a method  1401  including polarizing display and non-display information and illuminating a contact lens with the polarized display and non-display information in accordance with some embodiments. In the illustrated embodiment, the method  1401  (i) polarizes non-display information to form polarized non-display information and polarizes display information to form polarized display information (block  1403 ). (ii) illuminates a contact lens with the polarized non-display information while not illuminating the contact lens with the polarized display information (block  1405 ), and (iii) illuminates the contact lens with the polarized display information while not illuminating the contact lens with the polarized non-display information (block  1407 ). In some embodiments, the method  1401   includes substantially blocking the polarized display information at the non-display information path at the contact lens. 
       FIG.  15    shows an example configuration of a contact lens and a display panel reflected off a narrow spectral band beam splitter, in accordance with one embodiment of the present invention. Referring now to  FIG.  15   . a viewer’s eye  1500  is shown wearing a contact lens  1501  for viewing a display panel  1511  reflected off a narrow spectral band beam splitter  1510  while simultaneously viewing the surrounding ambient light  1516  visible through the beam splitter  1510 . As illustrated, beam splitter  1510  comprises a transparent substrate  1514  and a Rugate coating  1513  or other means to reflect narrow spectral bands of light. 
     The light  1517  emitted from the display panel  1511  is reflected off of the narrow band spectral reflection coating  1513  and is redirected towards the eye  1500 . This light does not need to be focused prior to illuminating the eye. Because the light is free to radiate out in a broad fashion, it is not restricted to just the cone of light  1517  depicted in  FIG.  15   . 
     After being reflected, light  1517  comprises only narrow bands of light. Narrow spectral notch filter  1504  in contact lens  1501  blocks this light from entering the eye except through the aperture in filter  1504 . The light that passes through the aperture in filter  1504  also passes through lenslet  1502  and filter  1503 , and into the pupil. Lenslet  1502  substantially collimates light  1517  such that the eye’s biological lenses can properly focus the image onto the retina. 
     Light  1516  from the surrounding environment passes through transparent substrate  1514  and through narrow spectral band reflector  1513 . The spectral bands of light  1516  that correspond to the spectral reflection bands of filter  1513  are reflected back, but the remaining broad bands of light pass on through unmodified. This broadband light illuminates the eye  1500  and contact lens  1501 . In particular, the light is free to pass through the narrow spectral notch filter  1504 , where it enters the pupil and is focused normally by the eye  1500  onto the retina. The light that passes through the aperture in filter  1504  is blocked from entering the pupil by filter  1503 . 
     As light  1517  and light  1516  focus onto the retina, the brain processes the two images from the two lights as if it were one image superimposed together. As a result, the viewer is able to see the image from the display together with the image from the surrounding environment. 
     The light  1517  from display  1511  that is broader in spectral bandwidth than the narrow bands of reflector  1513  passes through reflector  1513  and transparent substrate  1514 , thereby becoming visible to an observer. As such, in the illustrated embodiment, narrow bandpass filter  1512  blocks light that is broader in spectral bandwidth than the narrow bands of reflector  1513 , thereby blocking spectral bands broad enough to pass through filter  1513  and be visible to an observer. 
     In other embodiments, light  1517  is prevented from being visible to an observer by using a polarized filter of a first polarization for filter  1512  and polarizer filter  1515  of a second polarization. Polarizer filter  1512  blocks light of the second polarization and passes light of the first polarization. The passed light is free to transmit through filter  1513  and substrate  1514 , but is blocked by polarization filter  1515 , which blocks light of the first polarization. Light  1516  of the second polarization is free to pass through filter  1515 , substrate  1514 , and filter  1513 . 
       FIG.  16    illustrates an example configuration of a contact lens and a display panel reflected off a polarized beam splitter, in accordance with one embodiment of the present invention. Referring to  FIG.  16   , a viewer’s eye  1510  is shown wearing a contact lens  1501  for viewing a display panel  1611  reflected off a polarized beam splitter  1600  while simultaneously viewing the surrounding ambient light  1616  visible through the beam splitter  1600 . 
     Beam splitter  1600  comprises a transparent substrate  1614  and a polarization reflector  1613 . Light of a first polarization is transmitted through reflector  1613  and light of a second polarization is reflected by reflector  1613 . 
     The light  1617  emitted from the display panel  1611  is reflected off reflector  1613  and redirected toward the eye  1500 . This light does not need to be focused prior to illuminating the eye. As the light is free to radiate out in a broad fashion, it is not restricted to just the cone of light  1617  depicted in  FIG.  16   . 
     After reflection, light  1617  comprises only light having the second polarization. Polarization filter  1504  in contact lens  1501  blocks this light from entering the eye everywhere except through the aperture in filter  1504 . The light that passes through the aperture in filter  1504 , passes through lenslet  1502  and filter  1503 , and eventually enters the pupil. Lenslet  1502  substantially collimates light  1617  such that the eye’s biological lenses can properly focus the image onto the retina. 
     Light  1616  from the surrounding environment of the first polarization passes through transparent substrate  1614  and through polarization reflector  1613 ; light  1616  of a second polarization is reflected back. Light  1616  of the first polarization illuminates eye  1500  and contact lens  1501 . This light is free to pass through the polarization filter  1504 , where it enters the pupil and is focused normally by the eye  1500  onto the retina. The light that passes through the aperture in filter  1504  is blocked from entering the pupil by filter  1503 . 
     As light  1617  and light  1616  focus onto the retina, the brain processes the two images from the two lights as if it were one image superimposed together. As a result, the viewer is able to see the image from the display together with the image from the surrounding environment. 
     The light  1617  from display  1611  that is of the first polarization passes through reflector  1613  and through transparent substrate  1614 , thereby becoming visible to an observer. Polarization filter  1612  blocks light of a first polarization such that there is no light passing through filter  1613 . thereby preventing light  1617  from being visible to an observer. 
       FIG.  17    shows an example configuration of a contact lens and display pixels in front of an LCD display panel, in accordance with one embodiment of the present invention. Referring to  FIG.  17   . a viewer’s eye  1500  is depicted wearing a contact lens  1501  for viewing display pixels  1711  in front of an LCD display panel  1712  while simultaneously viewing the surrounding ambient light  1716  visible through display pixels  1711  and the LCD display panel  1712 . 
     Depending on the embodiment, display pixels  1711  may comprise any suitable pixel construction. Examples of this include electroluminescent pixels, reflected electroluminescent pixels, and pixels reflected from a projector. The filters and lenslet in contact lens  1501  enable the wearer to view pixels  1711  simultaneously with viewing light  1716  from the surrounding environment. 
     In operation, light  1716  is frequently brighter than pixels  1711 , making it difficult for the viewer to see pixels  1711 . Accordingly, in the illustrated embodiment, the pixels of LCD display panel  1712  can be adjusted to block some of light  1716  so that pixels  1711  are not overpowered by light  1716 . 
     Light  1716  of a first polarization passes through polarization filter  1714 . Each pixel within LCD display  1712  is set to a desired polarization orientation such that polarization filter  1713  blocks or passes the desired amount of light for each pixel. In this way, each pixel  1711  can have the amount of light  1716  passing through it attenuated to a desired level. 
       FIG.  18    illustrates an example configuration of a contact lens and an electroluminescent display panel that is polarized by an array of LCD pixels, in accordance with one embodiment of the present invention. Referring to  FIG.  18   , a viewer’s eye  1500  is shown wearing a contact lens  1501  for viewing an electroluminescent display panel  1812  that is polarized by and array of LCD pixels  1811  while simultaneously viewing the surrounding ambient light  1816  visible through the display panel. 
     In the illustrated embodiment, some or all of the pixels in electroluminescent display panel  1812  emit light during a first time period. Light from the display panel  1812  of a first polarization passes through polarization filter  1813 . For each pixel of display  1812  that is set to emit light, the corresponding pixel from LCD panel  1811  is set to not change the polarization of light passing through filter  1813 . For each pixel of display  1812  that is not set to emit light, the corresponding pixel from LCD panel  1811  is set to change the polarization of light passing through filter  1813  to a second polarization. 
     Light  1816  of a first polarization also passes through polarization filter  1813 , while light  1816  of a second polarization gets blocked. Light  1816  passing through LCD pixels  1811  is set to either the first polarization or the second polarization depending on the setting of LCD pixels  1811 . Those pixels  1811  corresponding to illuminated pixels of display  1812  are set to pass light of a first polarization, while those pixels  1811  corresponding to non-illuminated pixels of display  1812  are set to pass light of a second polarization. 
     Light of the first polarization is blocked by filter  1504  everywhere except through the aperture in filter  1504 . Light passing through the aperture of filter  1504  is substantially collimated by lenslet  1502 . After passing through lenslet  1502 , this light passes through filter  1503  and into the pupil, where it is imaged onto the retina by the eye’s biological optics. 
     Light of the second polarization passes through filter  1504  and into the pupil, where it is imaged onto the retina by the eye’s biological optics. Light of the second polarization passing through the center aperture is blocked by filter  1503 . 
     The above discussion describes how light  1816  and light coming from display pixels  1812  make their way to the retina during a first time period. During a second time period, display pixels  1812  are turned off and LCD pixels  1811  are all set to pass light  1816  of the second polarization. During this second time period, all of the light  1816  of the second polarization passes through filter  1504  and is imaged onto the retina by the eye’s biological optics. 
     During the first period, light  1816  passing through illuminated pixels  1812  is blocked from passing through filter  1504 . This allows the illuminated pixels  1812  to be seen without having to over power the light  1816  from the surrounding environment. 
     The duty cycle between the first time period and the second time period can be controlled. By increasing the percentage of time allocated to the second time period, the attenuation of light  1816  is reduced while the attenuation of light from display pixels  1812  is increased. This variation of attenuation is only for light  1816  that passes through illuminated pixels  1812 . Light  1816  passing through non-illuminated pixels  1812  is polarized to the second polarization in both time periods, and therefore is never attenuated. 
       FIG.  19    shows an example configuration of a contact lens and an LCD panel that is backlit by an electroluminescent panel, in accordance with one embodiment of the present invention. Referring to  FIG.  19   , an observer’s eye  1500  is shown wearing a contact lens  1501  for viewing an LCD panel  1911  that is backlit by an electroluminescent panel  1912  while simultaneously viewing the surrounding ambient light  1919  visible through the LCD display panel  1911 . 
     Light from electroluminescent panel  1912  radiates out in all directions. It is polarized by polarizer  1916  prior to passing through LCD pixels  1911  and polarizer  1915 . LCD pixels  1911  are set to adjust the amount of light from panel  1912  that can pass through polarizer  1915 . Specifically, the LCD pixels  1911  may be set to pass all of the light passing through polarizer  1916 , none of the light passing through polarizer  1916 , or any gray level in between. 
     During a first period, LCD panel  1913  is set to pass light from panel  1912  polarized to an orientation that does not pass through polarizer filter  1504 , but passes through filter  1503 . Light from panel  1912  is prevented from being visible to an observer by polarizers  1917  and  1918  along with LCD panel  1914 . During the first period when panel  1912  is on. LCD panel  1914  is set to not allow light to pass through polarizer  1918 . 
     Polarizers  1917  and  1918  along with LCD panel  1914  are not required for the wearer to see the image created by LCD pixels  1911 . Their main function is to prevent an observer from seeing the image created by LCD pixels  1911 . Their second function is to block light  1919  from reaching the viewer’s eyes during the first time period. Without items  1917 ,  1918 . and  1914 , light  1919  passes through panel  1912  and is processed just like the light from panel  1912 , except that light  1919  is already substantially collimated by virtue of its distance from the eye. For this reason, center lenslet  1502  de-collimates this light causing it to be defocused on the retina by the eye’s biological optics. This defocusing of light  1919  causes it to be highly diffused and therefore not affect the image created by LCD pixels  1911 . Because of this, items  1917 ,  1918 , and  1914  are not absolutely required to prevent light  1919  from interfering with the image created by LCD pixels  1911 . 
     During a second time period, panel  1912  is turned off and LCD panel  1914  is set to pass light  1919  through polarizer  1917 . Pixels  1911  are set to pass all of the light  1919  passing through polarizer  1916  to also pass through polarizer  1915 . LCD panel  1913  is set to pass light  1919  polarized to an orientation that passes through polarizer filter  1504 . From this point, it is focused onto the retina by the eye’s normal biological optics. The portion of this light that passes through the aperture opening in filter  1504  is blocked by filter  1503 . 
     The duty cycle between the first time period and the second time period can be controlled. By increasing the percentage of time allocated to the second time period, the amount of light  1919  imaged onto the retina is increased and the amount of light from panel  1912  that is modulated by LCD pixels  1911  imaged onto the retina is decreased. In this way, the relative brightness of the surrounding environment image and the display image can be optimized for a desired balance. 
       FIG.  20    shows an example configuration of a contact lens and an LCD panel that is backlit by an electroluminescent panel with a second LCD panel, in accordance with one embodiment of the present invention. Referring now to  FIG.  20   , a viewer’s eye  1500  is shown wearing a contact lens  1501  for viewing an LCD panel  2011  that is backlit by an electroluminescent panel  2012  with a second LCD panel  2014  while simultaneously viewing the surrounding ambient light  2019  visible through the LCD display panel. The second LCD panel  2014  creates an image that is not visible to the wearer, but is visible to an observer. 
     The configuration of the display panel  2000  shown in  FIG.  20    is similar to the operation described in  FIG.  19   , except an array of LCD pixels  2014  replaces the LCD panel  1914  of  FIG.  19   . 
     Light from electroluminescent panel  2012  radiates out in all directions. It is polarized by polarizer  2016  prior to passing through LCD pixels  2011  and polarizer  2015 . LCD pixels  2011  are set to adjust the amount of light from panel  2012  that can pass through polarizer  2015 . In particular. LCD pixels  2011  may be set to pass all of the light passing through polarizer  2016 . none of the light passing through polarizer  2016 , or any gray level in between. 
     During a first period, LCD panel  2013  is set to pass light from panel  2012  polarized to an orientation that does not pass through polarizer filter  1504 , but passes through filter  1503 . 
     During the first period, light from panel  2012  also passes through polarizer  2017  and is modulated by LCD pixels  2014  and polarizer  2018 . LCD pixels  2014  are set to adjust the amount of light from panel  2012  that can pass through polarizer  2018 . Specifically, the LCD pixels  2014  can be set to pass all of the light passing through polarizer  2017 , none of the light passing through polarizer  2017 , or any gray level in between. The image created by LCD pixels  2014  is visible to an observer. 
     During a second time period, panel  2012  is turned off and LCD pixels  2014  are set to pass light  2019  through polarizer  2017 . Pixels  2011  are set to pass all of the light  2019  passing through polarizer  2016  to also pass through polarizer  2015 . LCD panel  2013  is set to pass light  2019  polarized to an orientation that passes through polarizer filter  1504 . From this point, it is focused onto the retina by the eye’s normal biological optics. The portion of this light that passes through the aperture in filter  1504  is blocked by filter  1503 . 
     The duty cycle between the first time period and the second time period can be controlled. By increasing the percentage of time allocated to the second time period, the amount of light  2019  imaged onto the retina is increased and the amount of light from panel  2012  that is modulated by LCD pixels  2011  imaged onto the retina is decreased. In this way, the relative brightness of the surrounding environment image and the display image can be optimized for a desired balance. This duty cycle control of relative brightness of the image from LCD pixels  2011  also affects the brightness of the image created by LCD pixels  2014  as seen by an observer. 
     In some embodiments, display panel  2000  may be viewable while not wearing contact lens  1501 . If display panel  2000  is viewed from a distance by an observer on the left and an observer on the right, each observer would be able to see a display image while simultaneously seeing through the display to the surrounding environment on the other side of the display. The viewer to the left will see an image created during the first time period by LCD pixels  2011 , whereas the viewer to the right will see an image created during the first time period by LCD pixels  2014 . During the second time period, both viewers are able to see through the display to whatever is on the other side. Thus, the display panel  2000  appears like a see-through display to both viewers, but with a different display image presented. In this foregoing embodiment. LCD panel  2013  is not required. 
       FIG.  21    depicts an example configuration of a contact lens and an image projected onto a partially reflective panel, in accordance with one embodiment of the present invention. Referring to  FIG.  21   , a viewer’s eye  1500  is shown wearing a contact lens for viewing an image projected by image projector  2115  onto a partially reflective panel  2100  while simultaneously viewing the surrounding ambient light  2118  visible through the partially reflective panel  2100 . 
     As illustrated, transparent substrate  2111  is etched or molded to have concave or convex surfaces on one side. Partially reflective material is then deposited onto these surfaces to form partial reflectors  2112 . A second transparent substrate  2114  is bonded to the first substrate  2111  by an optical adhesive  2113  that is substantially of the same coefficient of refraction as substrates  2111  and  2114 . Adhesive  2113  completely fills the voids between reflectors  2112  and substrate  2114 . 
     Reflective panel  2100  is constructed of substrate  2111 , reflectors  2112 . adhesive  2113 , and substrate  2114  in such manner that the thickness of panel  2100  is substantially uniform in thickness and substantially uniform in its coefficient of refraction. As a result, light transmitting through partial reflective panel  2100  passes through without any refraction. However, light reflected by reflectors  2112  is reflected at various angles due to the curved nature of reflectors  2112 . This allows a viewer to see the image projected by projector  2115  reflected off reflective surface  2112  from multiple viewing positions. 
     Depending on the embodiment, partial reflectors  2112  may be constructed using thin metallic films that are thin enough to transmit some light, yet thick enough to reflect some light. For example, aluminum having a thickness ranging from  200  to  3000  angstroms could be used to provide various degrees of reflectivity versus transmission. Partial reflectors  2112  may also be constructed by depositing Rugate coatings onto substrate  2111 . Rugate coatings can be made to reflect certain wavelengths of light while transmitting other wavelengths. Yet other embodiments may use reflective polarizers for reflectors  2112 . These reflectors reflect light of one polarization and transmit light of a second polarization. 
     Light  2117  from projector  2115  is projected onto reflective panel  2100 . Some or all of this light is reflected by reflectors  2112  at divergent angles. The size of the curved surfaces of reflectors  2112  should be the same size as, or smaller than, the pixels projected onto panel  2100 . Each pixel is then reflected in a diverging manner as if the light was emanating from the reflective surface. In this way, reflective panel  2100  appears as an image plane to the viewer. Optics and filters in contact lens  1501  enable the wearer to see the image being reflected by reflective panel  2100  even though it is placed very near to the wearer’s eye. 
     In those embodiments where the reflective surface  2112  is a narrow band Rugate coating, only narrow bands of light from projector  2115  are reflected towards the viewer. In such an embodiment, filter  1504  may comprise a narrow band notch filter blocking the reflected light from entering the pupil except through the aperture opening at the center of filter  1504 . The light passing through this aperture is substantially collimated by lenslet  1502  and passes through filter  1503  before entering the pupil. From there, the eye’s biological optics focuses the light onto the retina. Additionally, narrow bandpass filter  2116  may be added to projector  2115  so that only narrow bands of light are projected onto narrow band reflectors  2111 , thus preventing any projected light from being seen by an observer. 
     Broadband light  2118  from the surrounding environment predominantly passes through reflectors  2112  un-modified and illuminates the eye  1500  and contact lens  1501 . Since it is broadband light, it mostly passes through the narrow band spectral notch filter  1504  and enters the pupil, where it is imaged onto the retina by the eye’s biological optics. Light  2118  passing through lenslet  1502  is blocked from entering the pupil by filter  1503 . 
     In those embodiments where the reflective surface  2112  is a polarization reflector, only light of a first polarization from projector  2115  is reflected towards the viewer. In such an embodiment, filter  1504  may comprise a polarization filter that blocks light of the first polarization and transmits light of a second polarization. In addition, polarization filter  2116  of a first polarization may be added to projector  2115  to only project light of the first polarization, so that no light transmits through reflectors to be seen by an observer. 
     Unpolarized light  2118  from the surrounding environment is polarized to a second polarization by reflectors  2112  and illuminates the eye  1500  and contact lens  1501 . Light  2118  of the second polarization is transmitted through polarized filter  1504  and is focused onto the retina by the eye’s biological optics. 
     In those embodiments where the reflective surface  2112  is a neutral partial reflector, the light from projector  2115  is conditioned by using filter  2116 . Where filter  2115  is a narrow bandpass filter, filter  1504  is a narrow notch filter. Where filter  2115  is a polarization filter of a first polarity, filter  1504  is a polarization filter of a second polarization. Either way, light from projector  2115  is conditioned by filter  2116  and partially reflected by reflectors  2112  back to the viewer’s eye. The light from projector  2115  is then blocked from entering the pupil by filter  1504  everywhere except through the center aperture opening. The light passing through the center aperture opening is substantially collimated by lenslet  1502  and passes through filter  1503 . It then enters the pupil and is imaged onto the retina by the eye’s biological optics. 
     Some of light  2118  from the surrounding environment transmits through partial reflectors  2112  and illuminates the eye  1500  and contact lens  1501 . It passes through filter  1504  into the pupil, where it is imaged onto the retina by the eye’s biological optics. 
       FIG.  22    shows an example configuration of a contact lens and an LCD panel that is illuminated by light projected onto a partially reflective back panel, in accordance with one embodiment of the present invention. Referring to  FIG.  22   , a viewer’s eye  1500  is shown wearing a contact lens  1501  for viewing an LCD panel  2200  that is illuminated by light  2217  from light source  2219  projected onto a partial reflector  2212  while simultaneously viewing the surrounding ambient light  2218  visible through the LCD display panel  2200 . 
     Transparent substrate  2211  is etched or molded to have concave or convex surfaces on one side. Partially reflective material is then deposited onto these surfaces to form partial reflectors  2212 . 
     A polarizer  2215  is bonded to substrate  2211  by an optical adhesive  2213  that is substantially of the same coefficient of refraction as substrate  2211 . Adhesive  713  completely fills the voids between reflectors  2212  and polarizer  2215 . 
     The reflective panel is constructed of substrate  2211 , reflectors  2212 , adhesive  2213 , and polarizer  2215  in such manner that the thickness of LCD display panel  2200  is substantially uniform in thickness and substantially uniform in its coefficient of refraction. As a result, light transmitting through LCD display panel  2200  passes through without any refraction. However, illumination light  2217  from light source  2219  is reflected off reflectors  2212  at various angles due to the curved nature of reflectors  2212 . This allows a viewer to see the reflected light from multiple angles. 
     Partial reflectors  2212  can be constructed using thin metallic films that are thin enough to transmit some light, yet thick enough to reflect some light. For example, aluminum having a thickness ranging from  200  to 3000 angstroms could be used as it provides various degrees of reflectivity versus transmission. In other embodiments, partial reflectors  2212  may be constructed by depositing Rugate coatings onto substrate  2211 . Rugate coatings can be made to reflect certain wavelengths of light while transmitting other wavelengths. 
     Light  2217  from light source  2219  is illuminated onto reflective surface  2212  after passing through polarizer  2216 , LCD pixels  2214 , and polarizer  2215 . LCD pixels  2214  modulate the gray levels of light transmitted through polarizer  2215  and on to reflective surface  2212 . This modulation of individual pixels forms an image. Some or all of this light is reflected by reflectors  2212  at divergent angles back through polarizer  2215  and LCD pixels  2214 . The size of the curved surfaces of reflectors  2212  should be the same size or smaller as LCD pixels  2214 . Each pixel is reflected in a diverging manner as if the light was emanating from the reflective surface. 
     Optics and filters in contact lens  1501  enable the wearer to see the image being reflected by reflective surface  2212  even though it is placed very near to the wearer’s eye. 
     In those embodiments where the reflective surface  2212  is a narrow band Rugate coating, only narrow bands of light from light source  2219  are reflected towards the viewer. Filter  1504  blocks the reflected light from entering the pupil except through the aperture opening at the center of filter  1504 . The light passing through this aperture is substantially collimated by lenslet  1502  and passes through filter  1503  before entering the pupil. From there, the eye’s biological optics focus the light onto the retina. 
     Optionally, narrow bandpass filter  2220  can be added to light source  2219  so that only narrow bands of light are projected onto narrow band reflectors  2211 , thereby preventing any projected light from being seen by an observer. 
     Broadband light  2218  from the surrounding environment mostly passes through reflectors  2212  un-modified. Polarizer  2215  polarizes light  2218  and LCD pixels  2214  alter this polarization orientation, without modulating the intensity of light  2218 . After passing through LCD pixels  2214 , light  2218  illuminates the eye  1500  and contact lens  1501 . Since it is broadband light, it mostly passes through the narrow band spectral notch filter  1504  and enters the pupil, where it is imaged onto the retina by the eye’s biological optics. Light  2218  passing through lenslet  1502  is blocked from entering the pupil by filter  1503 . 
     In some embodiments, partial reflectors  2212  may be neutral filters rather than narrow band spectral filters. In such embodiments, the light  2217  is still a narrow band light. Some of this narrow band light  2217  from light source  2219  is partially reflected by reflectors  2212  back to the viewer’s eye and is blocked from entering the pupil by RGB notch filter  1504  except through the center aperture opening. The light passing through the center aperture opening is substantially collimated by lenslet  1502  and passes through filter  1503 . It then enters the pupil, where it is imaged onto the retina by the eye’s biological optics. 
     Some of light  2218  from the surrounding environment is transmitted through partial reflectors  2212  and illuminates the eye  1500  and contact lens  1501 . It passes through notch filter  1504  into the pupil, where it is imaged onto the retina by the eye’s biological optics. 
       FIG.  23    illustrates an example configuration of a contact lens and an LCD panel that is side-illuminated through a light spreader in accordance with one embodiment of the present invention. Referring to  FIG.  23   , a viewer’s eye  1500  is shown wearing a contact lens  1501  for viewing an LCD panel  2300  that is side-illuminated through a light spreader  2315  while simultaneously viewing the surrounding ambient light  2318  visible through the LCD display panel  2300 . 
     Transparent substrate  2311  is etched or molded to have concave or convex surfaces on one side. Partially reflective material is then deposited onto these surfaces to form partial reflectors  2312 . 
     Light spreader  2315  is bonded to the first substrate  2311  by an optical adhesive  2313  that is substantially of the same coefficient of refraction as substrates  2311  and  2315 . Adhesive  2313  completely fills the voids between reflectors  2312  and substrate  2315 . 
     The reflective panel is constructed of substrate  2311 , reflectors  2312 , adhesive  2313 , and light spreader  2315  in such manner that the thickness of panel  2300  is substantially uniform in thickness and substantially uniform in its coefficient of refraction. As a result, light transmitting through LCD panel  2300  passes through without any refraction. However, light reflected by reflectors  2312  is reflected at various angles due to the curved nature of reflectors  2312 . This allows a viewer to see the reflected light from multiple angles. 
     In some embodiments, partial reflectors  2312  may be constructed using thin metallic films that are thin enough to transmit some light, yet thick enough to reflect some light. For example, aluminum having a thicknesses ranging from  200  to 3000 angstroms could be used as it provides various degrees of reflectivity versus transmission. In other embodiments, partial reflectors  2312  may also be constructed by depositing Rugate coatings onto substrate  2311 . Rugate coatings can be made to reflect certain wavelengths of light while transmitting other wavelengths. 
     Light  2320  from light source  2319  is illuminated onto reflective surface  2312  after passing through polarizer  2321  of a first polarization and being spread out uniformly by light spreader  2315 . LCD pixels  2314  modulate the gray levels of light transmitted through polarizer  2317 . This modulation of individual pixels forms an image. 
     Optics and filters in contact lens  1501  enable the wearer to see the image generated by LCD panel  2300  even though it is placed very near to the wearer’s eye. 
     In those embodiments where the reflective surface  2312  is a narrow band Rugate coating, only narrow bands of light from light source  2319  are reflected towards the viewer. In such embodiments, filter  1504  is a narrow band notch filter blocking the reflected light from entering the pupil except through the aperture opening at the center of filter  1504 . The light passing through this aperture is substantially collimated by lenslet  1502  and passes through filter  1503  before entering the pupil. From there, the eye’s biological optics focuses the light onto the retina. 
     Broadband light  2318  from the surrounding environment passes through polarizer  2316  of a second polarization and then mostly passes through reflectors  2312  un-modified. Since light  2318  is now polarized to a second polarization, LCD pixels  2314  modulate its gray levels in the negative of the gray levels for light  2319 . Thus, the bright pixels from light  2319  correspond to dim pixel of light  2318  and vice versa. 
     The pixel modulated light  2318  illuminates the eye  1500  and contact lens  1501 . Since it is broadband light, it mostly passes through the narrow band spectral notch filter  1504  and enters the pupil, where it is imaged onto the retina by the eye’s biological optics. Light  2318  passing through lenslet  1502  is blocked from entering the pupil by filter  1503 . 
     In some embodiments, partial reflectors  2312  may be neutral filters rather than narrow band spectral filters. In such embodiments, the light  2320  is still narrow band light. Some of this narrow band light  2320  from light source  2319  is partially reflected by reflectors  2312  back to the viewer’s eye and is blocked from entering the pupil by RGB notch filter  1504 , except through the center aperture opening. The light passing through the center aperture opening is substantially collimated by lenslet  1502  and passes through filter  1503 . It then enters the pupil, where it is imaged onto the retina by the eye’s biological optics. 
     Some of light  2318  from the surrounding environment is transmitted through partial reflectors  2312  and illuminates the eye  1500  and contact lens  1501 . It passes through notch filter  1504  into the pupil, where it is imaged onto the retina by the eye’s biological optics. 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. Likewise, the various diagrams may depict an example architectural or other configuration for the invention, which is done to aid in understanding the features and functionality that can be included in the invention. The invention is not restricted to the illustrated example architectures or configurations, but the desired features can be implemented using a variety of alternative architectures and configurations. Indeed, it will be apparent to one of skill in the art how alternative functional, logical or physical partitioning and configurations can be implemented to implement the desired features of the present invention. Also, a multitude of different constituent module names other than those depicted herein can be applied to the various partitions. Additionally, with regard to flow diagrams, operational descriptions and method claims, the order in which the steps are presented herein shall not mandate that various embodiments be implemented to perform the recited functionality in the same order unless the context dictates otherwise. 
     Although the invention is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the other embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. 
     Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as meaning “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; the terms “a” or “an” should be read as meaning “at least one,” “one or more” or the like; and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, where this document refers to technologies that would be apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future. 
     A group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although items, elements or components of the invention may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. 
     The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent. The use of the term “module” does not imply that the components or functionality described or claimed as part of the module are all configured in a common package. Indeed, any or all of the various components of a module, whether control logic or other components, can be combined in a single package or separately maintained and can further be distributed in multiple groupings or packages or across multiple locations. 
     Additionally, the various embodiments set forth herein are described in terms of exemplary block diagrams, flow charts and other illustrations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives can be implemented without confinement to the illustrated examples. For example, block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.