Patent Publication Number: US-2020298761-A1

Title: Display system for a vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/821,204, filed on Mar. 20, 2019, and entitled “E-MIRROR MATRIX SCATTER ABSORPTION,” and U.S. Provisional Patent Application No. 62/824,559, filed on Mar. 27, 2019, and entitled “MIRROR ASSEMBLY FOR A VEHICLE,” which are incorporated by reference in their entirety in this disclosure. 
    
    
     BACKGROUND 
     Vehicles are equipped with electronic rear-view mirrors that allow drivers to see the environment behind the vehicles without turning their heads around. In the vehicular space, electronic-mirrors or e-mirrors have been developed to convey information in a vehicle. An electronic mirror is a display device that allows content to be viewable in the reflective state and to be a display device in the display state. 
     However, there is a need to have a traditional reflection-based mirror as a backup if the cameras or other image processing electronics become non-operational. Although not required, it is also desirable to have the features of automatic luminance control when in the display mode and auto dimming when in the traditional mirror mode. 
     Automatic dimming rear-view mirrors utilize a rear light sensor to measure an intensity of trailing headlights and a forward light sensor to measure an intensity of an ambient light to control the dimming. As the trailing headlight intensity changes, an electrochromic element within the automatic dimming rear-view mirrors changes an attenuation level of the trailing headlights reflected by the rear-view mirror. The attenuation adjustment of the rear-view mirror is based on an intensity of the ambient light. In low ambient conditions, the attenuation rapidly adjusts to changes in the trailing headlights. In higher ambient conditions, the attenuation slowly adjusts to the changes in the trailing headlights. The attenuation does not consider a human eye adaptation to changes in the ambient light and the trailing headlights. 
       FIG. 1  illustrates an electronic mirror or e-mirror  10  according to one prior art implementation. A rear cover  12  serves as a housing  14  for the mirror  10 . The housing  14  cooperates with a front bezel  16  having an opening  18  sized to receive a lens  20 . The lens  20  is adjusted between a reflective state and a display state by a toggle switch  22  to allow the electronic mirror to be oriented towards a headliner of a vehicle during a display mode. 
       FIG. 2  illustrates a side-view of the prior art electronic mirror  10  as described in  FIG. 1 . As shown, a display  24  cooperates with a mirror element  26 , which is disposed proximate an electrochromic absorber  28 . Conventionally, electrochromic materials have been used for the electrochromic absorber  28  of the electrochromic mirror element. Illumination  30  from a source element, such as headlights from a vehicle rearward of the mirror, may be projected through the electrochromic absorber  28  toward the mirror element  26 . 
     The mirror element  26  may reflect about 50% of the light  32  and allow 50% transmission of content from the display  24  to be seen. A phenomenon known as matrix scatter may occur when light  32  enters the display  24 . In an electronic mirror  10  that includes a display state and a mirror or reflective state, matrix scatter may be particularly noticeable when mirror reflectance is at its lowest level. Matrix scatter may form a star pattern and may include multiple colors due to, for example, a diffraction pattern. Collimated light  32 , such as the light from headlights, may increase the visual effect of matrix scatter. Accordingly, rear view electronic mirrors that have a display state and a reflective state may experience a high level of matrix scatter in the reflective mode. 
     SUMMARY 
     A display system includes a display disposed in a housing. An electronic lens assembly is disposed in the housing proximate to and cooperating with the display. The electronic lens assembly includes one or more layers including a mirror element layer, a reflective polarizer layer cooperating with the mirror element layer, a rotator cell layer cooperating with the reflective polarizer layer, and a linear polarizer layer cooperating with the rotator cell layer and disposed opposite the reflective polarizer layer. A controller cooperates with the display and the electronic lens assembly and is configured to adjust the rotator cell layer of the electronic lens assembly between a reflective state in a first mode and a semi-transparent display state in a second mode. 
     In another aspect, an electronic mirror assembly includes a housing and a bezel cooperating with the housing, the bezel defining at least one aperture therein. A display is disposed in the housing. The display includes a display element configured to present content and a backlight cooperating with the display element to source light to generate an image on the display element. 
     An electronic lens assembly is disposed in the housing proximate the display. The electronic lens assembly includes one or more layers, including a mirror element layer, a reflective polarizer layer cooperating with the mirror element layer, a rotator cell layer cooperating with the reflective polarizer layer, and a linear polarizer layer cooperating with the rotator cell layer and disposed opposite the reflective polarizer layer. 
     A light sensing system having at least one sensor that receives and detects light from a light source is provided. A controller is disposed in the housing and cooperates with the display, the electronic lens assembly and the light sensing system. The controller is configured to adjust the rotator cell layer of the electronic lens assembly between a reflective state in a first mode and a semi-transparent display state in a second mode in response to input from the light sensing system. 
     In yet another aspect, a light sensing system for adjusting a reflective state of an electronic lens assembly of an electronic mirror assembly includes at least one sensor. The at least one sensor includes an aspherical lens, a light sensor device, and a light pipe defining an optical center. The light pipe includes a first end proximate the aspherical lens and a second end proximate the light sensor device. The light sensor device is offset from the optical center of the light pipe and includes a photosensitive area that receives and detects the light from the light source. 
     A controller cooperates with the at least one sensor. The controller is configured to adjust the electronic lens assembly between a reflective state in a first mode and a semi-transparent display state in a second mode in response to input from the at least one light sensor. 
     The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a prior art electronic mirror. 
         FIG. 2  is an exploded side view of the prior art electronic mirror of  FIG. 1 . 
         FIG. 3  is an exploded perspective view of an electronic display system in accordance with one or more aspects of the disclosure. 
         FIG. 4  is a perspective view of a light sensing system for the electronic display system, which is in accordance with one or more aspects. 
         FIG. 5  is a top view of the light sensing system of  FIG. 4 , which is in accordance with one or more aspects. 
         FIG. 6  is a side, cutaway view of the light sensing system of  FIG. 4 , which is in accordance with one or more aspects. 
         FIG. 7  is a side, cutaway view of the light sensing system of  FIG. 4 , which is in accordance with one or more aspects. 
         FIG. 8  is a graph of optical gain of the light sensing system of  FIG. 4 , which is in accordance with one or more aspects. 
         FIG. 9  is a graph of optical gain of the light sensing system of  FIG. 4 , which is in accordance with one or more aspects. 
         FIG. 10  is a schematic diagram illustrating an exemplary implementation of the electronic display system including a display and electronic lens assembly in accordance with one or more aspects of the disclosure. 
         FIG. 11  is a fragmentary side plan view illustrating at least one exemplary implementation of the electronic display system including a display and electronic lens assembly in accordance with one or more aspects of the disclosure. 
     
    
    
     The present disclosure may have various modifications and alternative forms, and some representative aspects are shown by way of example in the drawings and will be described in detail herein. Novel aspects of this disclosure are not limited to the forms illustrated in the above-enumerated drawings. Rather, the disclosure is to cover modifications, equivalents, and combinations falling within the scope of the disclosure as encompassed by the appended claims. 
     DETAILED DESCRIPTION 
     Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” “forward,” “rearward,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions. 
     Referring to the Figures, wherein like numerals indicate like parts throughout the several views,  FIG. 3  illustrates an electronic display system  40 . The electronic display system  40  may be a display system in the form of a mirror assembly, such as an electronic mirror or e-mirror. The mirror assembly may include a rear-view mirror, a visor mirror, an exterior side mirror or another type of vehicle display and/or mirror. Alternatively, the display system  40  in accordance with one or more aspects of the disclosure may comprise another type of display system, such as an instrument cluster, heads-up display or the like. 
     The electronic display system  40  shown in  FIG. 3  may be configures as an electronic mirror assembly  42  for use in the interior of a motor vehicle. The electronic mirror assembly  42  may be positioned adjacent a forward portion of a vehicle interior (not shown). For example, in one or more aspects, the electronic mirror assembly  42  may additionally be positioned on or proximate a windshield or windscreen (not shown) of the vehicle. It is understood that the electronic mirror assembly  42  or other form of electronic display system could be implemented in other regions of the vehicle, such as dashboard, console or other interior space and positioned on or proximate a structural portion of the vehicle, including, but not limited to, a vehicle panel or headliner, vehicle roof surface or vehicle frame to accomplish the objectives of this disclosure. 
     The electronic mirror assembly  42  includes housing  44  that may receive and support one or more components of the electronic mirror assembly  42 . The housing  44  cooperates with positioning elements  46  to mount the electronic mirror assembly  42  to a portion of the vehicle interior (not shown). The electronic mirror assembly  42  of the electronic display system  40  may include a control circuit or controller  48  having a printed wire board or printed circuit board (PCB)  50  and one more input devices  52  mounted thereon in electrical communication with the PCB  50 . The PCB  50  may include one or more sensors, a processor, and memory, as well as other components, such as a display driver, and a battery. 
     The controller  48  may include one or more processors, each of which may be embodied as a separate processor, an application specific integrated circuit (ASIC), or a dedicated electronic control unit. The controller  48  may be any sort of electronic processor (implemented in hardware, software, or a combination of both) installed in a vehicle to allow the various electrical subsystems to communicate with each other. The controller  48  also includes tangible, non-transitory memory (M), e.g., read only memory in the form of optical, magnetic, and/or flash memory. 
     The controller  48  may be equipped with memory for performing a set of program instructions. The memory may be a non-transitory computer-readable medium. At least one memory including computer-program instructions may be configured to, with at least one processor, cause the controller to carry out a process. Computer-readable and executable instructions embodying the present method may be stored in memory (M) and executed as set forth herein. The executable instructions may be a series of instructions employed to run applications on the controller  48  (either in the foreground or background), and allow either automated control of the vehicular subsystems, or direct control through engagement of an occupant of the vehicle in any of the provided human machine interface (HMI) techniques, such as the input device  52 . 
     The input device  52  may include any type of device that provides input the controller  48 , such as touch-activated instructions inputted from a touch screen, voice-activated commands input from an audio device, manual inputs, such as a mechanical or electrical stimulus, external inputs from an external device, or the like, that activates, deactivate, or adjusts one or more functions of the electronic mirror assembly  42 . In one or more non-limiting aspects of the disclosures, the input device  52  may be a button on the PCB  50  that communicates with the controller  48  to adjust the electronic mirror assembly  42  between one or more display modes, such as from a reflective state in a first mode or a mirror mode and a display state in a second mode or a video mode, may activate or deactivate a display  54  or adjust an optical property of the electronic mirror assembly  42 . 
     The electronic mirror assembly  42  includes a projection device or display  54  disposed within the housing  44 . The display  54  may be any sort of device capable of generating or configured to generate an image or digitally render information to present to a viewer for display on a projection surface such as an electronic display. For example, in one or more aspects, the display  54  may include a backlight  70  and a projection surface or display element  72  cooperating with the backlight  70  as shown in  FIG. 10 . 
     The display  54  may implement a standard display with a variable luminance capability. The display  54  is generally operational to provide visual information to a user. In some aspects, the display  54  may be a thin-film-transistor display with an active backlight. In other aspects, the display  54  may be a liquid crystal display with the active backlight. Other display technologies may be implemented to meet the design criteria of a particular application. In a first mode or mirror mode, a brightness of the display  54  may be set to a minimum controlled value. In a display mode, the brightness of the visual information presented by the display  54  may be controlled based on the rear light intensity and the ambient light intensity. 
     An electronic lens assembly  55  may be configured as an electronically variable optical device adjustable between a first mode or mirror mode and a second mode or display mode. The electronic lens assembly  55  is generally operational to provide an active system to control the mirror reflection rate (or level). In the first mode or mirror mode, the electronic lens assembly  55  may be adjusted by the controller  48  to vary the reflection rate based on the rear light intensity and the ambient light intensity. In the second mode or display mode, the electronic lens assembly  55  may be adjusted by the controller  48  to provide a maximum transmission rate of the visual information on the display  54  that is viewable through the electronic lens assembly  55 . The maximum controlled transmission rate may occur at a minimum controlled reflection rate. 
     The electronic lens assembly  55  may include one or more layers cooperating to provide the electronically variable optical device. The one or more layers of the electronic lens assembly may include a mirror element or mirror element layer  56  having a first side disposed proximate to and adjustable relative to a light emission direction of the display  54  and a second side opposite the first side. The mirror element layer  56  includes a semi-transparent reflective surface. The semi-transparent reflective surface of the mirror element layer  56  may be one of a semi-transparent mirror or a semi-transparent reflective polarizing layer. 
     For example, the mirror element layer  56  may include a partially reflective surface that provides a mirror surface to reflect images from the rear of the vehicle when the display  54  is inactive. The mirror element layer  56  may additionally incorporate a partially transparent surface that allows information or content generated on the display  54  to be viewed by a viewer through the mirror element layer  56 . The mirror element layer  56  may also be an active polarizer. 
     A flex element  57  may implement an electrical interface. The flex element  57  is generally operational to operate or energize the one or more layers of the electronic lens assembly  55  in the electronic mirror assembly  42 . In completed assemblies, the flex element  57  may electrically connect to the one or more layers of the electronic lens assembly  55 . 
     The housing  44  of the electronic mirror assembly  42  may further include a cover surface or bezel  58  at least partially enclosing one or more of the controller  48 , display  54  and electronic lens assembly  55  of the electronic mirror assembly  42 . A bezel  58  cooperates with the housing and defines at least one aperture  59  or open side therein may be configured to face a viewer of the electronic mirror assembly  42  and is sized to at least partially receive and cooperate with a lens  60 . The bezel  58  may also include one or more openings for other elements, switches and/or sensors. The lens  60  may be disposed proximate the electronic lens assembly  55  and is generally transparent to allow images generated by the display  54  or images reflected by the electronic lens assembly  55  to be viewed by the viewer. It is also understood that the lens  60  may be incorporated as part of the electronic lens assembly  55 . The electronic lens assembly  55  may be in a generally parallel, coplanar arrangement with the lens  60 . 
     A switch or button  62  cooperates with the input device  52  and extends through an aperture  64  in the bezel  58 . The button  62  may be positioned to align with an opening  64  in the front bezel  58 . The button  62  may have one or more functions and may be configured as one or more buttons  62 . 
     In one or more of the aspects, the switch or button  62  additionally may cooperate with the input device  52  to adjust the one or more components of the electronic mirror assembly  42 , such as adjustment of the electronic lens assembly  55  from a first position to at least one second position. A light sensing system  100  may also be provided in the bezel  58 . The light sensing system may include a rear facing light sensor, shown as reference numeral  66  in the Figures, and may further include a front facing light sensor  68 . The light sensing system  100  may record ambient lighting conditions and cooperate with the controller  48  to adjust the luminance settings of the display  54  or the mirror reflectance of the electronic lens assembly  55 . 
     Referring now to  FIGS. 4-9 , the light sensing system  100  of the electronic display system is described in greater detail. The light sensing system  100  may include at least one sensor having an aspherical lens  102 . The aspherical lens  102  may be disposed on the bezel  58  as shown in  FIG. 3  and may include an anti-glare coating. The aspherical lens  102  may be adjacent to a light pipe  112 . The light pipe may define an optical center include a first end that may be proximal to the aspherical lens  102 , and a second end that may be distal to a light sensor device. 
     In one non-limiting aspect, the aspherical lens  102  may be formed with a 2.0 mm diameter, a 1.0 mm radius spherical dome, and a 2.0 mm overall length. In another non-limiting aspect, the aspherical lens  102  may be formed with a 3.0 mm diameter, a 1.0 mm radius spherical dome, and a 2.0 mm overall length. Alternative dimensional values are also envisioned for the aspherical lens  102 . 
     The at least one sensor of the light sensing system  100  may further include at least one light sensor device  104 . The light sensor device  104  may be disposed at the second end of the light pipe  112 . The light sensor device  104  may be a logarithmic light sensor. The light sensor device  104  may include a dynamic range of operation, particularly for light levels. For example, the light sensor device  104  may be used in daytime operation or similar high illuminance conditions, the light sensor device  104  may be used in nighttime operation or similar low illuminance conditions, and the light sensor device  104  may be used throughout a range between daytime operation and nighttime operation. 
     For example, when the light sensor device  104  is the logarithmic sensor, the logarithmic sensor may perform automatic dimming during nighttime operation, and the logarithmic sensor may perform automatic luminance control during daytime operation. The light sensor  104  may be an SFH 5711, High Accuracy Ambient Light Sensor, from OSRAM Opto Semiconductors GmbH, with headquarters in Regensburg, Germany. In the light sensing system  100 , the light sensor  104  may sense light at levels less than 1 LUX, such as 0.1 LUX, to levels far greater than 1 LUX, such as 60 LUX. 
     The light sensor device  104  may include a photosensitive area  106 . The light sensor device  104  may be offset  110  from the optical center defined by the light pipe  112 . The offset  110  of the light sensor device  104  may be set at a predetermined distance. For example, the offset  110  of the light sensor device  104 , such as the photosensitive area  106 , may be 0.4 mm. As another example, the offset  110  of the light sensor may be 0.65 mm. The offset  110  may be selected based on a design value for the angle of the mirror assembly  10  relative to the center-plane of the vehicle. The light sensor device  104  may include electrically conductive pins  108 . The electrically conductive pins  108  may be disposed at the second end of the light pipe  112 . 
     In one non-limiting aspect of the disclosure shown in  FIG. 3 , the light sensing system  100  may include a first sensor  66  cooperating with the bezel  58  of the electronic mirror assembly  42  and a second sensor  68  disposed on the housing  44  of the electronic mirror assembly  42  of the electronic display system  40 . The housing  44  may include an aperture for receiving the second sensor  68 . The second sensor  68  may generally be disposed on the electronic mirror assembly  42  opposite the first sensor  66 , wherein the first light sensor  66  may have a field of view directed toward a rear of the vehicle. Conversely, the second light sensor  68  may have a field of view directed toward a front of the vehicle. As such, the first light sensor  66  may be referred to as a rear-facing light sensor, and the second light sensor  68  may be referred to as a front-facing light sensor. 
     In one non-limiting aspect, the second light sensor  68  or front-facing light sensor of the electronic mirror assembly  42  of the electronic display system  40  may be an ambient light sensor that may be configured to generate an ambient intensity value by logarithmic sensing the ambient light signal. The first light sensor  66  or rear-facing light sensor of the electronic mirror assembly  42  may be configured to generate a rear intensity value by logarithmic sensing the rear light signal proximate the electronic mirror assembly  42 . A controller  48  of the electronic display system  40  may be configured to generate the reflectance value in response to the ambient intensity value and the rear intensity value measured by the first light sensor  66  and second light sensor  68 . The refection value generally adjusts the reflectance rate of the rear light signal by the electronic display system  40  with a negative fractional power of the rear intensity value. The reflected light signal may be viewed by the user at an intensity level that is based on both a brightness of the rear light signal and a brightness of the ambient light signal. 
     Referring to  FIG. 6 , a side, cutaway view of the light sensing system  100  is illustrated, which is in accordance with one or more aspects. Light  114  is shown entering the aspherical lens  102 , wherein at least some of the light  114  being focused by the aspherical lens  102  is directed toward the photosensitive area  106  of the light sensor device  104 . 
     Referring to  FIG. 7 , a side, cutaway view of the light sensing system  100  is illustrated, which is in accordance with one or more aspects. The light sensing system  100  includes an aperture collar  116 . The aperture collar  116  may receive the aspherical lens  102 . The aperture collar  116  may surround the aspherical lens  102 . The aperture collar  116  may conceal a portion of the aspherical lens  102 . As one example, the aperture collar  116  may form part of the bezel  58 . The aperture collar  116  may prevent a double-peak condition from occurring for optical gain. 
     The light sensing system  100  may include an amplifier that boosts an output from the light sensor  104 . The amplifier may be a “rail-to-rail” output type amplifier. The amplifier may include one or more load resistors. The amplifier and/or the one or more load resistors may set a gain factor for the light sensor device  104 . For example, the gain of the amplifier may be set at approximately 1.18. The gain factor may be set to not exceed the dynamic range of the light sensor  104 . 
     According to one or more aspects, in a light sensing system  100 , optical gains may be adjustable depending on dimensional size of an aspherical lens  102 . For example, for the vehicle, the size of the aspherical lens  102  may be selected to compensate for vehicle rear window light transmission characteristics. Additionally, a focus point of the aspherical lens  102  may be optimized to achieve a desired diffusion profile. Further, an offset for the light sensor device  104  in relation to an optical center of a light pipe  112  may be optimized to achieve a desired optical gain profile. Additionally, the light sensing system  100  may be used in conjunction with or separate from a second light sensing system. 
       FIG. 8  illustrates a graph  120  of optical gain versus collimator source angle of light from the light source for the light sensing system  100 , where the offset  110  is set at 0.65 mm and the overall length from the light pipe  112  to the aspherical lens  102  is 5.1 mm. As shown in the graph of  FIG. 8 , optical gain is at a maximum of around 8.5 at 10° (10 degrees) for the angle of light from the light source. Additionally, at 12° (12 degrees) for the angle of light from the light source, the optical gain is around 7.75. A defocusing condition exists, which reduces optical gain at, for example, the 12° (12 degree) angle of light from the light source. That defocusing condition generally flattens out the optical gain, which may allow the occupant greater flexibility in orienting the mirror assembly  42 , particularly in relation to the center plane. 
       FIG. 9  illustrates a graph  122  of optical gain versus collimator source angle of light from the light source for the light sensing system  100 , where the offset  110  is set at 0.65 mm, the overall length from the light pipe  112  to the aspherical lens  102  is 5.1 mm, and the aperture collar  116  is used. The aperture collar  116  yields a single-peak condition, as opposed to the double-peak condition witnessed in  FIG. 8 . For example, as seen in the graph  120  of  FIG. 8 , a first peak for optical gain occurs at 10° (10 degrees) and a second peak occurs at 20° (20 degrees). Including the aperture collar with the offset set at 0.65 mm and the overall length from the light pipe  112  to the aspherical lens  102  set at 5.1 mm may result in a single-peak condition for optical gain, instead of the double-peak condition witnessed in the graph  122  in  FIG. 9 . 
     In  FIG. 9 , the maximum optical gain, which may be around 8.1, may occur at 10° (10 degrees) for the angle of light from the light source. At 12° (12 degrees), the optical gain may be around 7.5. As such, the aperture collar  116  may achieve the single-peak condition, while having negligible impact on optical gain at certain angles of light. For example, when compared to  FIG. 8 , the maximum optical gains may occur at 10° (10 degrees) and may be nearly identical, as may the values for optical gains at 12° (12 degrees). 
     Referring now to  FIGS. 10-11 , a diagram of the electronic mirror assembly  42  of the electronic display system  40  is illustrated. The electronic mirror assembly  42  includes a display  54  having at least a backlight  70  and a projection surface or display element  72  cooperating with the backlight  70  and configured to present content on the display element  72 . The backlight  70  sources light to the display element  72 . The display  54  may be a light emitting display, such as an organic light emitting diode (OLED) display, liquid crystal display (LCD) a thin-film transistor (TFT) display or other suitable display for the presentation of information. The backlight  70  sources light to the projection surface or display element  72 , which, using technology such as liquid crystal cell-based technology, determines a pattern to illuminate and make viewable to the viewer of the display  54 . 
     As is best shown in  FIG. 10 , the one or more layers of the electronic lens assembly  55  may include a mirror element layer  56  and a reflective polarizer or reflective polarizer layer  76  disposed proximate to and cooperating with the second side  56   b  of the mirror element layer  56 . The reflective polarizer layer  76  may be formed as a reflective polarizer film. Two or more classes of reflective polarizer materials may be used for the reflective polarizer layer  76 , including, but not limited to, 3M′ Reflective Polarizer Mirror (RPM) and 3M™ Windshield Combiner Film (WCF), both available from THE 3M COMPANY, with headquarters located in Maplewood, MN. Other reflective polarizer materials having similar properties such as wire grid polarizers may be used to form the reflective polarizer layer  76  in other aspects. 
     A rotator cell layer  78  may be disposed adjacent and cooperate with the reflective polarizer layer  76 . The rotator cell layer  78  may be formed as an electronically controlled active wave plate. The rotator cell layer  78  may include a liquid crystal layer such as a Thin Film Transistor (TFT) liquid crystal display (LCD), otherwise referred to as the TFT display layer. Alternatively, the rotator cell layer  78  may be formed as another form of liquid crystal cell device configuration, such as multiplexed film compensated super twist nematic (FSTN), twisted nematic (TN), in-plane switching (IPS), multi-domain vertical alignment (MVA) or another type of liquid crystal display mode that causes light polarization rotation. 
     The rotator cell layer  78  may be an active half-wave plate and may have two controllable states, which may be controlled by controller  48 . The controller  48  may be configured to control the rotator cell layer  78  to be in a selected state according to a desired mode of operation of the electronic mirror assembly  42 . One of these states may be no change to polarized light. In this state, polarized light may be pass through without rotation. The other state of the two states may be rotation of polarized light by 90° (90 degrees). One of these states may be used for the first mode or mirror mode and the other state may be used for the second mode or display mode. 
     The liquid crystal layer of the rotator cell layer  78  rotates polarized light by 90° (90 degrees). In one non-limiting aspect, the rotator cell layer  78  further comprises a liquid crystal layer, wherein the liquid crystal layer of the rotator cell layer  78  is activated to rotate polarized light by 90 degrees for the reflective state in the first mode and is deactivated for the semi-transparent display state in the second mode. In general, propagating light waves generate an electric field. The electric field oscillates in a direction that is perpendicular/orthogonal to the light wave&#39;s direction of propagation. Light is unpolarized when the fluctuation of the electric field direction is random. Light may be described as polarized when fluctuation of the electric field is highly structured, with laser beams being a common example of highly polarized light and sunlight or diffuse overhead incandescent lighting being examples of unpolarized light. 
     In one or more aspects of the disclosure, the display  54  and the rotator cell layer  78  may be electrically coupled to a controllable voltage source and the controller  48 . In response to activation of the display  54  by the controller  48 , the controllable voltage source may be configured to apply a voltage to adjust the rotator cell layer  78 . In response to activation of the display  54  by the controller  48  based upon output received from at least one of the input device  52  or light sensor system  100 , the controllable voltage source may be configured to apply a voltage to adjust the rotator cell layer  78  to adjust the electronic mirror assembly  55  between a reflective state in a first mode or mirror mode and a semi-transparent display state in a second mode or a display mode. The control voltage source may be applied by the controller  48  so that the crystals of the rotator cell layer  78  may either be orthogonal to the display  54  or perpendicular to the display  54 . When the crystals are parallel to the display  54 , the polarization of light is rotated. The controller  48  may either apply a drive voltage to turn on the rotator layer or remove the drive voltage to turn off the rotator cell layer  78 . The controller  48  may further apply a pulse width modulated (PWM) voltage to the display  54  described herein. 
     A linear polarizer or linear polarizer layer  80  may be disposed adjacent and cooperate with the rotator cell layer  78 . The linear polarizer layer  80  may be disposed on an opposing portion or side of the rotator cell layer  78  from the reflective polarizer layer  76 . 
     In a non-limiting aspect of the disclosure, at least one air gap layer  74  may provided between the display  54  and the linear polarizer layer  80  of the electronic lens assembly  55 . The at least one air gap layer  74 , or index matching layer, may overlap the display  54  and/or the electronic lens assembly  55 .  FIG. 11  illustrates a variation for implementation of the at least one air gap layer  74  in the display system  40 . Referring to  FIG. 11 , the at least one air gap layer  74  introduced in between the display element  72  of the display  54  and the linear polarizer layer  80  of the electronic lens assembly  55 . 
     The electronic lens assembly  55  of the electronic mirror assembly  42  may eliminate or reduce the scattering of light by rotating the polarization of the light passing through the reflective polarizer layer  76  so that light is absorbed by the linear polarizer layer  80 . One way to rotate the polarization is to use the active half-wave plate of the rotator cell layer  78  placed between the reflective polarizer layer  76  and the linear polarizer layer  80 . The active half-wave plate of the rotator cell layer  78 , which may use a twisted nematic (TN) liquid crystal cell, may have two operating positions. 
     In a first mode or mirror mode, the active half-wave plate of the rotator cell layer  78  is not driven or activated by the controller  48 . Polarized ambient light from a headlight or the like is rotated by 90° (90 degrees) and may be absorbed by the linear polarizer layer  80 , which eliminates light matrix scatter by eliminating light entering the display element  72  of the display  54 . In a second mode position or display mode, the rotator cell layer  78  is driven or activated by the controller  48 , such that no change is made to polarized light. The polarized light is not rotated by the rotator cell layer  78  such that the polarized light is aligned to the transmission axis and may pass through the reflective polarizer layer  76  and thereby, the light from the display  54  through the linear polarizer layer  80 . The controller  48  may drive or activate the rotator cell layer  78  of the electronic lens assembly  55  in response to input from one or more output sources, including, but not limited to, a signal or output from the input device  52  and/or as signal or output from the light sensor system  100  as described herein. 
     A solution to eliminate matrix scatter from the display  54  from the electronic mirror assembly  42  of the electronic display system  40  is described in greater detail. Matrix scatter is described as a star pattern emanating from the specular distinct image, and often there will be different colors visible because of the diffraction pattern generating matrix scatter. Therefore, reflected matrix scatter causes the light component, which is passed through an electronic lens assembly  55 , to not be effectively absorbed as a beam stop by a display  54 , which is, in turn, reflected towards the viewer. Since the matrix scatter is caused by structures (e.g. row and column lines) internal to the display  54 , external anti-reflection counter measures are not be effective for this reflection component. 
     In one or more aspects of the disclosure, an antireflection (AR) layer may be provided between the display  54  and the electronic lens assembly  55  to reduce the reflection rate by approximately 4%. Between the display  54  and the electronic lens assembly  55 , the use of an AR layer reduces the amount of reflection by 2% for each air to glass interface because only half of the light may go through the electronic lens assembly  55  due to the reflective polarization film. In one or more aspects, when index matching the glass to air or front display polarizer to air with AR coating or motheye film, light is minimally reflected at these interfaces to a reflectance of less than 0.4% reflection. 
       FIG. 11  illustrates one aspect to compensate for matrix scatter, namely, to tilt or position the display  54  on an angle in a non-planar arrangement relative to the electronic lens assembly  55  to reduce matrix scatter. In one non-limiting example, the display  54  may be tilted or positioned at an angle of about 4° (4 degrees) relative to the electronic lens assembly  55 . For example, the top portion of the display  54  may be tilted away or positioned an angle of about 4° (4 degrees) from the electronic lens assembly  55  while the bottom portion of the display may be tilted toward the electronic lens assembly  55 . Alternatively, the top portion of the display  54  may be tilted toward or positioned an angle of about 4° (4 degrees) relative to the electronic lens assembly  55  while the bottom portion of the display  54  may be tilted away from the electronic lens assembly  55 . 
     The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other aspects for carrying out the claimed teachings have been described in detail, various alternative designs and aspects exist for practicing the disclosure defined in the appended claims.