PATENT DOCUMENT

Publication Number: US-12136691-B2
Application Number: US-202218145489-A
Country: US
Kind Code: B2

Title: System with one-way filter over light-emitting elements

Abstract:
A system may have an exterior display. The exterior display may display symbols that correspond to intended actions for the system or instructions for nearby viewers. The exterior display may include an array of light-emitting diodes, a collimator, a one-way filter to prevent sunlight from washing out the display, and a cover layer. The one-way filter may include a microlens array and a masking layer. The collimator is configured to collimate light from the array of light-emitting diodes and provide the collimated light to the one-way filter. The microlens array receives the collimated light and focuses the collimated light through a plurality of holes in the masking layer. In this way, the majority of display light is passed through the one-way filter towards a viewer. However, the majority of ambient sunlight is blocked by the masking layer, thus preserving a high contrast for the exterior display even in bright sunlight.

Claims:
What is claimed is: 
     
       1. A display, comprising:
 an array of light-emitting diodes configured to emit light; 
 a collimator that is configured to collimate the light; 
 a masking layer that includes a plurality of holes, wherein the masking layer has first and second opposing sides and wherein the masking layer is configured to block a majority of ambient light from passing from the second side to the first side; 
 a microlens array layer that is configured to focus a majority of the light from the collimator through the plurality of holes from the first side to the second side; 
 a spacer layer having different portions with different thicknesses, wherein the spacer layer is interposed between the masking layer and the microlens array layer, and 
 a transparent cover layer having a non-planar exterior surface, wherein the masking layer is interposed between the spacer layer and the transparent cover layer. 
 
     
     
       2. The display defined in  claim 1 , wherein each microlens in the microlens array layer is on a respective one of the different portions of the spacer layer. 
     
     
       3. The display defined in  claim 2 , wherein each one of the different portions of the spacer layer has a non-planar side that conforms to the masking layer and a planar side that is adjacent to the microlens array layer. 
     
     
       4. The display defined in  claim 3 , wherein the non-planar exterior surface of the transparent cover layer has convex curvature. 
     
     
       5. The display defined in  claim 4 , wherein the masking layer conforms to the transparent cover layer. 
     
     
       6. The display defined in  claim 1 , wherein the microlens array layer and the masking layer form a one-way filter. 
     
     
       7. The display defined in  claim 6 , wherein the one-way filter passes a majority of light from the array of light-emitting diodes in a first direction away from the array of light-emitting diodes. 
     
     
       8. The display defined in  claim 1 , wherein each microlens of the microlens array layer has a focal point that is aligned with a respective hole of the plurality of holes. 
     
     
       9. The display defined in  claim 1 , wherein a first center-to-center spacing of the plurality of holes is less than a second center-to-center spacing of the array of light-emitting diodes. 
     
     
       10. The display defined in  claim 9 , wherein the first center-to-center spacing is less than 0.3 millimeters and wherein the second center-to-center spacing is greater than 1 millimeter. 
     
     
       11. The display defined in  claim 1 , further comprising:
 a color conversion layer that is interposed between the microlens array layer and the masking layer, wherein the color conversion layer is configured to convert the light from the array of light-emitting diodes from a first color to a second, different color. 
 
     
     
       12. A display, comprising:
 a plurality of light sources; 
 a collimator that is configured to collimate light from the plurality of light sources; 
 a microlens array layer that includes a plurality of microlenses, wherein the collimator is interposed between the plurality of light sources and the microlens array layer; 
 a masking layer that includes a plurality of holes, wherein the microlens array layer is interposed between the collimator and the masking layer and wherein each microlens of the plurality of microlenses is aligned with a respective hole of the plurality of holes; 
 a transparent cover layer, wherein the masking layer is interposed between the transparent cover layer and the microlens array layer; and 
 an anisotropic filtering layer that is interposed between the transparent cover layer and the masking layer, wherein the anisotropic filter layer passes more light at an on-axis incident angle than at an off-axis incident angle. 
 
     
     
       13. The display defined in  claim 12 , wherein the microlens array layer and the masking layer form a one-way filter. 
     
     
       14. The display defined in  claim 13 , wherein the one-way filter passes a majority of light from the plurality of light sources in a first direction away from the plurality of light sources. 
     
     
       15. The display defined in  claim 12 , wherein a first center-to-center spacing of the plurality of holes is less than a second center-to-center spacing of the plurality of light sources. 
     
     
       16. The display defined in  claim 15 , wherein the first center-to-center spacing is less than 0.3 millimeters and wherein the second center-to-center spacing is greater than 1 millimeter. 
     
     
       17. The display defined in  claim 12 , further comprising:
 a color conversion layer that is interposed between the microlens array layer and the masking layer, wherein the color conversion layer is configured to convert the light from the plurality of light sources from a first color to a second, different color.

Description:
This application claims priority to U.S. provisional patent application No. 63/300,529, filed Jan. 18, 2022, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to systems and, more particularly, systems that have light-emitting elements. 
     BACKGROUND 
     Some systems have external output devices such as light-emitting elements. However, these external output devices may be limited in the type of information they can convey. These external output devices may also have worse contrast than desired in bright ambient light. 
     SUMMARY 
     A vehicle may have an exterior display. The exterior display may display symbols that correspond to intended actions for the vehicle or symbols that correspond to instructions for nearby pedestrians. 
     The exterior display may include an array of light-emitting diodes, a collimator, a one-way filter to prevent ambient sunlight from washing out the display, and a cover layer. The one-way filter may include a microlens array and a masking layer. The collimator is configured to collimate light from the array of light-emitting diodes and provide the collimated light to the one-way filter. 
     The microlens array in the one-way filter receives the collimated light and focuses the collimated light through a plurality of holes in the masking layer. In this way, the majority of display light is passed through the one-way filter towards a viewer. However, the majority of ambient sunlight is blocked by the masking layer, thus preserving a high contrast for the exterior display even in bright sunlight. 
     The masking layer in the exterior display may be formed by a black material (giving the display a black appearance in its off state). Alternatively, the masking layer may be a non-black color to provide a non-black appearance in the off state. As yet another option, the masking layer may have a high specular reflection. With this type of arrangement, ambient sunlight is reflected towards the ground (away from the viewer) to preserve display contrast and the display has a mirror-like appearance in the off state. 
     The exterior display may optionally include a color conversion layer, a filtering layer, and/or a supplemental diffuser layer. The exterior display may have a planar output surface (with corresponding planar display layers) or a non-planar output surface (with corresponding non-planar display layers). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side view of an illustrative vehicle in accordance with an embodiment. 
         FIG.  2    is a cross-sectional side view of an illustrative display with a one-way filter in accordance with an embodiment. 
         FIG.  3    is a front view of an illustrative masking layer in a one-way filter in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of an illustrative one-way filter in accordance with an embodiment. 
         FIG.  5    is a cross-sectional side view of an illustrative display with a one-way filter and a color conversion layer in accordance with an embodiment. 
         FIG.  6    is a cross-sectional side view of an illustrative display with a one-way filter and a diffuser layer in accordance with an embodiment. 
         FIG.  7    is a cross-sectional side view of an illustrative display with non-planar layers in accordance with an embodiment. 
         FIG.  8    is a front view of an illustrative display in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A system such as a vehicle or other system may have components that emit light. The components may include an exterior display that displays symbols and/or other information. The exterior display for a vehicle may be viewable by pedestrians or nearby vehicles and may signal the intentions of the vehicle. For example, the exterior display may display a stop symbol when the vehicle is about to stop or in the act of stopping. 
     The exterior display may routinely be operated in daytime conditions where sunlight levels are very high. If care is not taken, the bright sunlight may reduce contrast and wash out the display content. To preserve contrast in an exterior display, the display may be covered by a one-way filter that includes a microlens array and a mask with a plurality of holes. The microlens array may focus display light through the holes in the mask, allowing the display light to be visible to a viewer. At the same time, the mask may block the majority of sunlight, preventing reflections from washing out the display light. 
       FIG.  1    is a side view of a portion of an illustrative vehicle. In the example of  FIG.  1   , vehicle  10  is the type of vehicle that may carry passengers (e.g., an automobile, truck, or other automotive vehicle). Configurations in which vehicle  10  is a robot (e.g., an autonomous robot) or other vehicle that does not carry human passengers may also be used. Vehicles such as automobiles may sometimes be described herein as an example. 
     Vehicle  10  may be manually driven (e.g., by a human driver), may be operated via remote control, and/or may be autonomously operated (e.g., by an autonomous driving system or other autonomous propulsion system). Using vehicle sensors such as lidar, radar, visible and/or infrared cameras (e.g., two-dimensional and/or three-dimensional cameras), proximity (distance) sensors, and/or other sensors, an autonomous driving system and/or driver-assistance system in vehicle  10  may perform automatic braking, steering, and/or other operations to help avoid pedestrians, inanimate objects, and/or other external structures on roadways. 
     Vehicle  10  may include a body such as vehicle body  12 . Body  12  may include vehicle structures such as body panels formed from metal and/or other materials, may include doors  18 , a hood, a trunk, fenders, a chassis to which wheels are mounted, a roof, etc. Windows may be formed in doors  18  and other portions of vehicle body  12  (e.g., on the sides of vehicle body  12 , on the roof of vehicle  10 , and/or in other portions of vehicle  10 ). Windows, doors  18 , and other portions of body  12  may separate the interior of vehicle  10  from the exterior environment that is surrounding vehicle  10 . Doors  18  may be opened and closed to allow people to enter and exit vehicle  10 . Seats and other structures may be formed in the interior of vehicle body  12 . 
     Vehicle  10  may have automotive lighting such as one or more headlights (sometimes referred to as headlamps), driving lights, fog lights, daytime running lights, turn signals, brake lights, and/or other lights. In some cases, vehicle  10  may include an exterior display that is configured to display content at the exterior of the vehicle. As shown in  FIG.  1   , for example, vehicle  10  may have an exterior display such as display  16 . In general, display  16  may be mounted on front F of vehicle  10 , on an opposing rear portion of vehicle  10 , on the left and/or right sides of vehicle  10 , and/or on other portions of body  12 . In an illustrative configuration, which may sometimes be described herein as an example, display  16  is mounted to front F of body  12 . Display  16  may, for example, emit illumination  20  in the forward direction (e.g., in the +X direction in which vehicle  10  moves when driven forward in the example of  FIG.  1   ). 
     A wide variety of content may be displayed on display  16 . If desired, display  16  may be used to communicate with pedestrians or others nearby. Display  16  may display instructions or indicators for pedestrians. As an example, pedestrians may be waiting to cross in front of vehicle  10  after vehicle  10  has come to a stop at a crosswalk. To help inform the pedestrians that it is safe to cross, vehicle  10  may use display  16  to display an animation or image of a person walking. Alternatively, display  16  may display a green light or arrow to indicate safe crossing conditions. As yet another example, display  16  may convey an intended action for vehicle  10 . When vehicle  10  is in the process of stopping, about to stop, or actively stopped, display  16  may display an image of a stop sign, a symbol associated with stopping (e.g., a square or a red square), the word “stop” or “stopping” in text form, or another desired indicator. In general, any desired image or content may be displayed on display  16  to provide information to people in the vicinity of vehicle  10 . 
     Display  16  may have a viewing angle that is aligned with likely positions of pedestrians relative to vehicle  10 . If desired, multiple displays  16  may be positioned on the front of vehicle  10 . A first display may be positioned on the left side of the front of the vehicle and may be configured to display content towards the front-left of the vehicle. A second display may be positioned on the right side of the front of the vehicle and may be configured to display content towards the front-right of the vehicle. This example is merely illustrative. In general, vehicle  10  may include any desired number of exterior displays  16  at any desired position(s) on the body of the vehicle. 
     Vehicle  10  may have components  24 . Components  24  may include propulsion and steering systems (e.g., manually adjustable driving systems and/or autonomous driving systems having wheels coupled to body  12 , steering controls, one or more motors for driving the wheels, etc.), and other vehicle systems. Components  24  may include control circuitry and input-output devices. Control circuitry in components  24  may be configured to run an autonomous driving application, a navigation application (e.g., an application for displaying maps on a display), and software for controlling vehicle climate control devices, lighting, media playback, window movement, door operations, sensor operations, and/or other vehicle operations. For example, the control system may form part of an autonomous driving system that drives vehicle  10  on roadways autonomously using data such as sensor data. The control circuitry may include processing circuitry and storage and may be configured to perform operations in vehicle  10  using hardware (e.g., dedicated hardware or circuitry), firmware and/or software. Software code for performing operations in vehicle  10  and other data is stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) in the control circuitry. The software code may sometimes be referred to as software, data, program instructions, computer instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory, one or more hard drives (e.g., magnetic drives or solid-state drives), one or more removable flash drives or other removable media, or other storage. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of components  24 . The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, a central processing unit (CPU) or other processing circuitry. 
     The input-output devices of components  24  may include displays, light-emitting diodes and other light-emitting devices, haptic devices, speakers, and/or other devices for providing output. Output devices in components  24  may, for example, be used to provide vehicle occupants and others with haptic output, audio output, visual output (e.g., displayed content, light, etc.), and/or other suitable output. The input-output devices of components  24  may also include input devices such as buttons, sensors, and other devices for gathering user input, for gathering environmental measurements, for gathering information on vehicle operations, and/or for gathering other information. The sensors in components  24  may include ambient light sensors, touch sensors, force sensors, proximity sensors, optical sensors such as cameras operating at visible, infrared, and/or ultraviolet wavelengths (e.g., fisheye cameras, two-dimensional cameras, three-dimensional cameras, and/or other cameras), capacitive sensors, resistive sensors, ultrasonic sensors (e.g., ultrasonic distance sensors), microphones, radio-frequency sensors such as radar sensors, lidar (light detection and ranging) sensors, door open/close sensors, seat pressure sensors and other vehicle occupant sensors, window sensors, position sensors for monitoring location, orientation, and movement, speedometers, satellite positioning system sensors, and/or other sensors. 
     During operation, the control circuitry of components  24  may gather information from sensors and/or other input-output devices such as lidar data, camera data (e.g., two-dimensional images), radar data, and/or other sensor data. This information may be used by an autonomous driving system and/or driver&#39;s assistance system in vehicle  10 . Based on these measurements, user input, or other information, vehicle  10  may adjust exterior display  16 . 
     A vehicle occupant or other user of vehicle  10  may provide user input to the control circuitry of vehicle  10 . Cameras, touch sensors, physical controls, and other input devices may be used to gather the user input. Using wireless communications with vehicle  10 , remote data sources may provide the control circuitry of components  24  with database information. If desired, display  16  and/or other vehicle components may be adjusted based on user input and/or information from a remote data source. For example, information on road conditions (e.g., road size, road type, road shape, road surface, etc.) may be stored in a remote database and this information may be provided to vehicle  10  over a wireless communications link. During operation, vehicle  10  may adjust display  16  based on the road condition information. 
     Display  16  may have two-dimensional arrays of components. Display  16  may, for example, have arrays of light-emitting diodes and/or other light sources. The arrays may be arranged to form two-dimensional arrays with rows and columns or may be arranged with other two-dimensional layouts. 
     Because display  16  is positioned at the exterior of vehicle  10 , the display may be exposed to high levels of sunlight during daytime operation. If care is not taken, sunlight may reduce contrast in display  16  and wash out the display content. To preserve contrast in display  16  in bright sunlight, the display may be covered by a one-way filter. The one-way filter may allow the majority of display light to pass through the filter to the display viewer(s). The one-way filter may prevent the majority of ambient sunlight from reflecting off the display and also being viewable the display viewer(s). 
       FIG.  2    is a cross-sectional side view of an illustrative exterior display for vehicle  10 . Display  16  of  FIG.  2    may be mounted to body  12 . Body  12  may have a cavity that receives display  16 , display  16  may be attached to an outer surface of body  12 , and/or display  16  may be otherwise supported by body  12 . Display  16  may optionally have a housing formed separately from body  12 . As shown in  FIG.  2   , display  16  may include light sources  32  on a substrate  34 . Light sources  32  may be light-emitting diodes (LEDs) such as organic light-emitting diodes (OLEDs) or inorganic LEDs, lasers, lamps, etc. Substrate  34  may be a printed circuit or other desired substrate. 
     Light sources  32  may include light sources of a single color (e.g., blue LEDs or white LEDs) or light sources of multiple colors (e.g., red, blue, and green LEDs). In arrangements in which light sources  32  include different color light sources, light color may be adjusted by selectively activating and deactivating light sources  32 . 
     The light sources  32  emit light that travels in the positive X-direction through collimator  36 , one-way filter  38 , and cover layer  40 . Cover layer  40  (sometimes referred to as display cover layer  40 , transparent cover layer  40 , etc.) may be formed from a transparent material such as glass, plastic, sapphire, etc. The cover layer may have a transparency that is greater than 80%, greater than 90%, greater than 95%, greater than 99%, etc. 
     Light collimator  36  may be formed from one or more optical components such as illustrative collimating lenses  42 . In  FIG.  2   , each light source  32  is covered by a respective collimating lens  42 . Each collimating lens  42  collimates light for a respective light source  32 . The light collimator  36  in  FIG.  2    is formed using refraction-based lenses. However, this example is merely illustrative and other types of light collimators may be used if desired. For example, collimator  36  may include reflective structures such as conical mirrors, structures that propagate light using total internal reflection such as light pipes, etc. 
     As shown in  FIG.  2   , light sources  32  may emit light with a first angular spread  44  (sometimes referred to as viewing angle). The total magnitude of viewing angle  44  may be greater than 45 degrees, greater than 60 degrees, greater than 70 degrees, greater than 80 degrees, greater than 90 degrees, etc. Light collimator  36  collimates the light from each light source, thereby reducing the angular spread of the light. As shown in  FIG.  2   , after passing through light collimator  36 , the light from each light source  32  has a second angular spread  46  (sometimes referred to as viewing angle  46 ). The total magnitude of viewing angle  46  may be less than 40 degrees, less than 30 degrees, less than 25 degrees, less than 20 degrees, less than 10 degrees, etc. 
     The light that is collimated by collimator  36  is then incident on one-way filter  38 . One-way filter  38  may allow the majority of the collimated light from light sources  32  to pass through the filter in the positive X-direction (e.g., to a viewer  48 ). The light from light sources  32  may sometimes be referred to as display light. In addition to passing the majority of display light in the positive X-direction, one-way filter  38  may block the majority of ambient sunlight  56  from reflecting off of the display and washing out the display light. To achieve the desired filtering, one-way filter  38  includes a microlens array  50  and a masking layer  52  (sometimes referred to as mask  52 , light blocking layer  52 , light absorbing layer  52 , etc.). 
     Masking layer  52  may be formed from a light absorbing material that has a plurality of holes  54  (sometimes referred to as openings  54 , pinholes  54 , etc.). Each hole  54  may be aligned with a respective microlens in microlens array  50 . Each microlens in the microlens array receives collimated light from collimator  36  and focuses the collimated light through a respective hole  54 . In this way, the display light passes through masking layer  52  and reaches viewer  48 . 
     Ambient sunlight  56 , meanwhile, strikes the masking layer  52 . The majority of the sunlight will strike the non-hole area of the masking layer and be blocked (e.g., absorbed). Some amount of sunlight may still pass through holes  54  and be reflected back towards viewer  48 . However, the amount of ambient light reflections is sufficiently small to preserve a high contrast between the display light and reflections of the ambient sunlight (even in bright sunlight). 
     An alternative technique for mitigating ambient sunlight reflections is to include a heavily tinted layer in display  16 . However, the heavily tined layer may mitigate the brightness of the display light in addition to ambient sunlight reflections. The one-way filter of the display in  FIG.  2    mitigates the amount of attenuated display light, which improves the efficiency of display  16  (e.g., reduces power consumption). 
       FIG.  3    is a front view of masking layer  52  in  FIG.  2   . As shown, the masking layer includes an array of holes  54 . Each hole  54  may be aligned with a respective microlens in microlens array  50 . The masking layer may be formed from a black material that absorbs light. For example, the masking layer may absorb more than 80% of incident light, more than 90% of incident light, more than 95% of incident light, more than 99% of incident light, etc. 
     The appearance of the masking layer may dictate the off state cosmetic appearance of display  16 . When the display is on, the content formed by display light from display  16  will be viewable. However, when the display is off, masking layer  52  will be viewable through cover layer  40 . When the display is formed from a black light absorbing material, the display will appear to be black when turned off. The masking layer may be formed from other materials to provide display  16  with a difference appearance in its off state. As one example, the masking layer  52  may be formed from a material with a high specular reflection. In specular reflection, incident light at a given incident angle is reflected at the same (or similar angle). Since the sun is normally positioned at a high angle relative to the display, specular reflection may cause ambient light from the sun to be reflected into the ground (where it is not visible to viewer  48  in  FIG.  2   ). Therefore, even though the masking layer does not absorb the light in this scenario, the masking layer prevents (blocks) ambient sunlight from reaching the viewer (which ensures a high contrast in the display). When a display having a masking layer  52  with high specular reflection is in the off state, the display may have a mirror-like appearance. Masking layer  52  may also be formed from a light absorbing material having a non-black color (e.g., red, blue, purple, yellow, etc.) if desired. Masking layer  52  may also have different portions with different colors/appearances (e.g., a central portion of a first color and a peripheral ring-shaped portion with a second color, a left half of a first color and a right half with a second color, etc.). 
     If care is not taken, holes  54  in masking layer  52  may be visible to a viewer when the display is in the off state. To prevent this, the diameter of holes  54  and the pitch  58  between adjacent holes (e.g., the center-to-center spacing in the Y-direction and/or Z-direction) may be small. The diameter of holes  54  may be less than 0.2 millimeters, less than 0.1 millimeters, less than 0.5 millimeters, less than 0.1 millimeters, greater than 0.1 millimeters, etc. Pitch  58  may be less than 1 millimeter, less than 0.5 millimeters, less than 0.3 millimeters, less than 0.2 millimeters, less than 0.1 millimeters, between 0.2 millimeters and 0.3 millimeters, between 0.1 millimeter and 0.5 millimeters, etc. The smaller the pitch, the closer a viewer has to be to display  16  to be able to detect the presence of holes  54 . For example, at a pitch of 0.25 millimeters, holes  54  may not be detectable to the average human eye at about a 1-meter viewing distance. 
     In addition to mitigating the detectability of the holes when the display is off, using a small magnitude for pitch  58  prevents a screen door effect (a black mesh that is viewable between light-emitting areas) when display  16  is on. For example, at a pitch of 0.25 millimeters, a viewer may not be able to detect discrete light-emitting areas in the display (and instead perceive a continuous light-emitting area despite the fact that light only exits the display through holes  54 ) at about a 1-meter viewing distance. 
     The pitch of holes  54  is the same as the pitch of the microlenses in microlens array  50  (since each hole is aligned with a single respective microlens). The pitch of holes  54  may be lower than the pitch of light sources  32 . As shown in  FIG.  2   , light sources  32  may have a center-to-center spacing  60  (sometimes referred to as pitch  60 ). Pitch  60  may be greater than 1 millimeter, greater than 2 millimeters, greater than 3 millimeters, greater than 5 millimeters, between 2 millimeters and 3 millimeters, between 0.1 millimeter and 10 millimeters, less than 1 millimeter, less than 2 millimeters, less than 3 millimeters, less than 5 millimeters, etc. The ratio of pitch  60  to pitch  58  may be greater than 2, greater than 3, greater than 5, greater than 8, greater than 10, greater than 20, less than 2, less than 3, less than 5, less than 8, less than 10, less than 20, greater than 0.5, greater than 0.1, less than 0.5, less than 0.1, etc. 
     The total percent surface area taken up by holes  54  in masking layer  52  may be less than 20%, less than 15%, less than 10%, less than 5%, greater than 15%, greater than 10%, greater than 5%, greater than 1%, between 5% and 15%, etc. Take an example where the total percent surface area of holes  54  in masking layer  52  is 10%. This means that 90% of incident ambient sunlight will be blocked by masking layer  52 . The majority of the display light is focused through the holes, resulting in a high contrast between display light and reflected sunlight. 
     As shown in  FIG.  2   , there may be an air gap  62  between collimator  36  and one-way filter  38 . The magnitude of air gap  62  may be greater than 1 millimeter, greater than 3 millimeters, greater than 5 millimeters, greater than 10 millimeters, greater than 15 millimeters, between 10 millimeters and 15 millimeters, less than 20 millimeters, less than 15 millimeters, less than 10 millimeters, etc. If desired, a transparent filler (e.g., a low-index filler) may be used to fill air gap  62 . The transparent filler may conform to the surfaces of collimator  36  and microlens array  50 . 
       FIG.  4    is a cross-sectional side view of one-way filter  38  from  FIG.  2   . As shown in  FIG.  4   , the one-way filter  38  includes a microlens array  50  and a masking layer  52 . Microlens array  50  includes microlenses  64  and a spacer layer  66 . Microlenses  64  are formed on a first side of spacer layer  66  and masking layer  52  is formed on a second, opposing side of spacer layer  66 . 
     Microlenses  64  and spacer layer  66  may be formed from the same material or from different materials. Microlenses  64  and spacer layer  66  may be formed during a single manufacturing step (e.g., molded from a single material) or during multiple manufacturing steps. 
     Masking layer  52  may be formed by molding (e.g., a two-shot mold with microlens array  50 ), printing, one or more thin films (foils) that are attached to the microlens array, etc. 
     Spacer layer  66  may have a thickness  68  that matches the focal length of microlenses  64 . In this way, microlenses  64  focus light onto respective focal points (e.g., in a focal plane) that align with masking layer  52 . As shown in  FIG.  4   , collimated light  70  received by the microlens array is focused through holes  54  and passes through the masking layer  52 . Thickness  68  may be less than 1 millimeter, less than 0.5 millimeters, less than 0.3 millimeters, less than 0.2 millimeters, less than 0.1 millimeters, between 0.2 millimeters and 0.3 millimeters, between 0.1 millimeter and 0.5 millimeters, etc. The magnitude of thickness  68  may be within 20% of the focal length of microlenses  64 , within 10% of the focal length of microlenses  64 , within 5% of the focal length of microlenses  64 , within 3% of the focal length of microlenses  64 , etc. 
     The shape (and corresponding focal length) of microlenses  64  may be tuned to determine the viewing angle of light output from display  16 . Microlenses with small amounts of curvature (and a corresponding larger focal length) result in a smaller viewing angle in the light output from display  16 . Microlenses with large amounts of curvature (and a corresponding smaller focal length) result in a larger viewing angle in the light output from display  16 . 
     As previously mentioned, forming the holes in masking layer  52  with a small pitch may mitigate screen door effect in the display. Additionally, the screen door effect is mitigated because each microlens serves as a diffusing element that diffuses the light from light sources  32 . 
     If desired, one or more additional layers may optionally be incorporated into one-way filter  38  and/or display  16 .  FIG.  5    is a cross-sectional side view of an illustrative display with a color conversion layer. As shown in  FIG.  5   , color conversion layer  72  may be interposed between spacer layer  66  and masking layer  52 . The color conversion layer  72  (sometimes referred to as phosphor layer  72 , quantum dot layer  72 , etc.) may convert light of a first color into light of a second, different color. For example, the color conversion layer may convert blue light from light sources  32  into white light that is emitted from the display. The color conversion layer may include quantum dots such as red quantum dots (that convert blue light into red light) and green quantum dots (that convert blue light into green light). Color conversion layer  72  may be a blanket layer that covers the entire masking layer  52 . Alternatively, color conversion layer  72  may be patterned to provide display  16  with different colors of emitted light in different portions of the display. For example, the color conversion layer  72  may be formed over only a first half of the display but not a second half of the display. Alternatively, the color conversion layer  72  may output a first color of light in a first half of the display and a second, different color of light in a second half of the display. 
       FIG.  5    also shows how a filter layer  74  may optionally be included in display  16 . The filter layer is interposed between masking layer  52  and cover layer  40 . Filter layer  74  may filter one or more colors of light, as an example. The filter layer may filter (block) one or more colors of visible light and/or light at other wavelengths (e.g., infrared light, ultraviolet light, etc.). The filter layer may have anisotropic performance based on the incident angle of light. For example, the filter layer may pass more light at on-axis incident angles (e.g., light that is orthogonal to the surface of filter  74 ) than at off-axis incident angles (e.g., light that is at a shallow angle relative to the surface of filter  74 ). This type of anisotropic filtering may allow display light (from light sources  32 ) to pass through the filter while blocking light at other viewing angles. 
       FIG.  6    is a cross-sectional side view of an illustrative display with a diffuser layer in addition to a one-way filter. As shown in  FIG.  6   , the diffuser layer  76  is positioned between masking layer  52  and cover layer  40 . The diffuser layer  76  may provide additional diffusion of light from display  16  to mitigate the screen door effect in the display. Diffuser layer  76  may be susceptible to diffuse reflections from sunlight that reduce contrast in display  16 . Therefore, diffuser layer  76  may have a relatively low haze to prevent excessive sunlight reflections. Haze may be measured as the percentage of incident light scattered by more than 2.5 degrees through the material. The haze of diffuser layer  76  may be less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, between 1% and 20%, etc. 
     In  FIGS.  2  and  4 - 6   , the output surface of display  16  (e.g., the exterior surface of cover layer  40 ) is depicted as being planar. This example is merely illustrative. If desired, the display may have a non-planar output surface. Any or all of the components in the display may have a non-planar shape that conforms to the non-planar output surface.  FIG.  7    is a cross-sectional side view of an illustrative display with a convex output surface. As shown in  FIG.  7   , cover layer  40  has an outer surface  80  with convex curvature. Masking layer  52  has convex curvature that conforms to the curvature of cover layer  40 . This example is merely illustrative. The outer surface  80  may have concave curvature or other desired curvature (e.g., curvature with both convex and concave portions). 
     When the display has a non-planar output surface, spacer layer  66  in microlens array  50  may have different portions with different thicknesses. Each spacer layer portion has a corresponding microlens  64 . Including different spacer layer portions allows for the thickness of each spacer layer to be tuned to ensure that the focal point of each microlens aligns with a respective opening  54  in the masking layer  52 . 
       FIG.  8    is a front view of an illustrative display  16  that may be included in vehicle  10 . As shown in  FIG.  8   , the display may have a circular footprint. This example is merely illustrative. In general, display  16  may have any desired footprint (e.g., square, non-square rectangular, oval, etc.). Display  16  may be used to display a symbol  78 , an animation of a symbol, text, or any other desired content. As previously discussed, symbol  78  may correspond to an intended action for vehicle  10  (e.g., a square when the vehicle is stopped or stopping, a triangle when the vehicle is moving without intending to stop) and/or instructions to nearby pedestrians (e.g., a raised hand when pedestrians should not cross in front of the vehicle, a walking person when pedestrians should cross in front of the vehicle, etc.). 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20221222
Publication Date: 20241105
Grant Date: 20241105
Priority Date: 20220118
Inventors: TANG, XIAOFENG
WALLIS, BRYCE E
CHILD, CHRISTOPHER P
MAZUIR, Clarisse
STIEHL, KURT R
LIU, RONG
CHOI, YONG SEOK
Sun, Yu P
Assignee: APPLE INC
CPC Classifications: [{"code": "H10H29/142", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10H20/855", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10H20/856", "inventive": true, "first": true, "tree": "[]"}, {"code": "F21S43/2605", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21Y2115/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "F21S43/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L25/0753", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09F27/008", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09F21/048", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60Q1/507", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60Q1/543", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60Q1/547", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60Q1/5035", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09F9/33", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/255", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60Q1/0035", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/14", "inventive": false, "first": false, "tree": "[]"}, {"code": "F21S43/26", "inventive": true, "first": true, "tree": "[]"}, {"code": "F21Y2115/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L27/156", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S43/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L33/60", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 87161255