PATENT DOCUMENT

Publication Number: US-12153746-B1
Application Number: US-202217698669-A
Country: US
Kind Code: B1

Title: Electronic devices with illuminated reconfigurable touch controls and notifications

Abstract:
An electronic device may have a surface area that may or may not overlap a touch sensor and that may be illuminated. The surface area may have an appearance that matches adjacent housing surfaces when not illuminated from within the device. When it is desired to create notifications or reconfigurable touch controls, a pixel array under the surface area may be used to produce patterned illumination. A louver layer may be interposed between the pixel array and the surface area. The louver layer may have louvers that are tilted with respect to a surface normal associated with the surface area. The louver layer may have cores and claddings that are formed from materials that help impart a non-black appearance to the surface area when corresponding portions of the underlying pixel array are inactive and not emitting light.

Claims:
What is claimed is: 
     
       1. An electronic device having a touch sensitive surface area, comprising:
 a housing; 
 a touch sensor overlapped by the touch sensitive surface area; 
 layers including a louver layer overlapping the touch sensor; and 
 a pixel array configured to produce light that passes through the louver layer and creates illuminated reconfigurable touch controls on the touch sensitive surface area, wherein the layers are configured to provide a portion of the touch sensitive surface area in which no light from the pixel array is present with an appearance matched in color to an appearance of an adjacent surface of the housing. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the layers have a haze of at least 10%. 
     
     
       3. The electronic device defined in  claim 2  wherein the layers are partially transparent and wherein the portion of the touch sensitive surface area in which no light from the pixel area is present has a gray appearance. 
     
     
       4. The electronic device defined in  claim 2 , wherein the layers are partially transparent and wherein the portion of the touch sensitive area in which no light from the pixel array is present has a non-neutral color matching a non-neutral color of the adjacent surface of the housing. 
     
     
       5. The electronic device defined in  claim 4  wherein the adjacent surface of the housing and the touch sensitive surface area have matched textures. 
     
     
       6. The electronic device defined in  claim 2  wherein the layers are partially transparent and wherein the portion of the touch sensitive area in which no light from the pixel array is present has a non-neutral color. 
     
     
       7. The electronic device defined in  claim 2  wherein the touch sensitive surface area is characterized by a surface normal, wherein the louvers each have a louver core surrounded by louver claddings, and wherein the louver cores are tilted at a non-zero angle with respect to the surface normal. 
     
     
       8. The electronic device defined in  claim 7 , wherein the louver layer is configured to provide the portion of the touch sensitive surface with a gray appearance matched in color and texture to the appearance of the adjacent surface of the housing. 
     
     
       9. The electronic device defined in  claim 2 , wherein the louver layer is configured to provide the portion of the touch sensitive surface with a non-neutral color. 
     
     
       10. The electronic device defined in  claim 2 , wherein the louver layer is configured to provide the portion of the touch sensitive surface with a neutral color. 
     
     
       11. The electronic device defined in  claim 10  wherein the neutral color is gray and wherein the louver layer is configured to provide the portion of the touch sensitive surface with a gray color. 
     
     
       12. The electronic device defined in  claim 10  wherein the neutral color is white and wherein the louver layer is configured to provide the portion of the touch sensitive surface with a white color. 
     
     
       13. The electronic device defined in  claim 1  wherein the louver layer has a haze of at least 5%. 
     
     
       14. The electronic device defined in  claim 1  wherein the layers have a transmission of 10-90%. 
     
     
       15. The electronic device defined in  claim 1  wherein the pixel array comprises pixels selected from the group consisting of organic light-emitting diode pixels and crystalline semiconductor light-emitting diode pixels. 
     
     
       16. The electronic device defined in  claim 1  wherein the pixel array comprises a thin film transistor liquid crystal display, the electronic device further comprising a backlight that provides illumination for the pixel array. 
     
     
       17. The electronic device defined in  claim 1  wherein the pixel array comprises a scanning laser. 
     
     
       18. The electronic device defined in  claim 1  wherein the pixel array comprises a projection source. 
     
     
       19. The electronic device defined in  claim 18  wherein the projection source comprises a projection source selected from the group consisting of a digital light projector and a liquid-crystal-on silicon display. 
     
     
       20. The electronic device defined in  claim 1  wherein the pixel array comprises ultraviolet light-emitting pixels. 
     
     
       21. The electronic device defined in  claim 20  wherein the layers include a phosphor layer that creates visible light where struck by ultraviolet light from the pixel array. 
     
     
       22. The electronic device defined in  claim 1  wherein the pixel array comprises an array of adjustable-transmission pixels. 
     
     
       23. The electronic device defined in  claim 22  further comprising a backlight that produces backlight illumination for the array of adjustable-transmission pixels. 
     
     
       24. The electronic device defined in  claim 23  wherein the backlight has a light guide layer and a light source that emits light into the light guide layer that is scattered out of the light guide layer to produce the backlight illumination. 
     
     
       25. The electric device defined in  claim 23  wherein the backlight has an array of light-emitting diodes that produce the backlight illumination. 
     
     
       26. The electronic device defined in  claim 1  further comprising a light source that produces ultraviolet light. 
     
     
       27. The electronic device defined in  claim 26  wherein the layers comprise a phosphor layer that creates visible light where struck by the ultraviolet light. 
     
     
       28. The electronic device defined in  claim 27  further comprising a filter that blocks ultraviolet light that overlaps the phosphor layer, wherein the light source comprises an array of ultraviolet light-emitting pixels in the pixel array. 
     
     
       29. The electronic device defined in  claim 27  wherein the pixel array comprises an array of adjustable-transmission pixels, wherein the phosphor layer is between the array of adjustable-transmission pixels and the touch sensitive surface area, wherein ultraviolet light from the light source strikes the phosphor layer after passing through the array of adjustable-transmission pixels to create the visible light, and wherein the visible light passes through the louver layer and creates the illuminated reconfigurable touch controls on the touch sensitive surface area. 
     
     
       30. The electronic device defined in  claim 29  further comprising a filter between the touch sensitive surface area and the phosphor layer that blocks ultraviolet light. 
     
     
       31. The electronic device defined in  claim 29  further comprising a filter between the phosphor layer and the array of adjustable-transmission pixels that is configured to pass the ultraviolet light from the light source to the phosphor layer. 
     
     
       32. The electronic device defined in  claim 1  wherein the louver layer comprises a plurality of electrically adjustable louvers. 
     
     
       33. The electronic device defined in  claim 1  wherein the pixel array is not overlapped by a black masking layer. 
     
     
       34. The electronic device defined in  claim 1  further comprising a non-black opaque masking layer having openings aligned with emission areas of the pixel array. 
     
     
       35. The electronic device defined in  claim 34  wherein the non-black opaque masking layer has a checkerboard pattern or a striped pattern. 
     
     
       36. The electronic device defined in  claim 1  wherein the layers include a layer of colloidal semiconductor nanocrystals that generates visible light where struck by ultraviolet light. 
     
     
       37. The electronic device defined in  claim 1  wherein the layers comprise:
 a first layer of quantum dots selectively quenched using a first control voltage; 
 a second layer of quantum dots selectively quenched using a second control voltage; and 
 a third layer of quantum dots selectively quenched using a third control voltage. 
 
     
     
       38. The electronic device defined in  claim 1  further comprising:
 a backlight that produces backlight illumination for the pixel array, wherein the backlight has a light guide layer and a light source that emits light into the light guide layer that is scattered out of the light guide layer to produce the backlight illumination and wherein the light guide layer has holographic optical elements formed on one or more substrate layers. 
 
     
     
       39. The electronic device defined in  claim 1  further comprising:
 a backlight that produces backlight illumination for the pixel array, wherein the backlight has a light guide layer and a light source that emits light into the light guide layer that is scattered out of the light guide layer to produce the backlight illumination; and 
 a lenticular lens film formed over the light guide layer. 
 
     
     
       40. The electronic device defined in  claim 1  wherein the layers further include an image transport layer disposed between the pixel array and the louver layer and wherein the image transport layer comprises a coherent fiber bundle or is formed from a layer of Anderson localization material. 
     
     
       41. The electronic device of  claim 1  wherein the layers are configured to provide the portion of the touch sensitive surface area with an appearance matched in texture to the appearance of the adjacent surface of the housing. 
     
     
       42. An electronic device having a touch sensitive region, comprising:
 a touch sensor configured to gather touch input on the touch sensitive region; 
 louvers overlapping the touch sensor, wherein the louvers are tilted at a non-zero angle with respect to a surface normal of the touch sensitive region; and 
 a pixel array configured to produce light that passes through the louvers and creates illuminated touch controls on the touch sensitive region, wherein the louvers are configured to provide a colored appearance to the touch sensitive region when the pixel array is not producing light. 
 
     
     
       43. The electronic device of  claim 42  wherein each louver comprises a louver core surrounded by a louver cladding and wherein the louver cores are titled at the non-zero angle with respect to the surface normal of the touch sensitive region. 
     
     
       44. An electronic device having a touch sensitive surface area, comprising:
 a pixel array that is configured to emit light, wherein the light creates reconfigurable touch controls on the touch sensitive surface area; 
 a touch sensor overlapping the pixel array and configured to gather touch input on the touch sensitive surface area; and 
 a louver layer configured to provide a non-black appearance to a portion of the touch sensitive surface area in which no light from the pixel array is present, wherein the touch sensor is interposed between the pixel array and the louver layer.

Description:
This application claims the benefit of U.S. Provisional Application No. 63/169,544, filed Apr. 1, 2021, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, electronic devices with touch sensors. 
     BACKGROUND 
     Electronic devices may have touch sensors. For example, a laptop computer may have a track pad with touch sensor. During operation of the laptop computer, a user may provide touch input to the trackpad to control the laptop computer. 
     SUMMARY 
     An electronic device may have a touch sensitive surface area that is configured to receive touch input such as a trackpad surface area. Adjustable illumination may be provided that creates illuminated touch sensor controls in the touch sensitive area. 
     A trackpad surface area or other touch sensitive area on an electronic device housing may be provided with an appearance when not illuminated from within that has a non-black appearance such as a neutral appearance (e.g., white or gray) or a non-neutral color (e.g., gold, red, blue, etc.). 
     When it is desired to create reconfigurable buttons or other reconfigurable controls on the trackpad surface area, a pixel array under the trackpad surface area may be used to produce illumination. The portion of the trackpad surface area that is currently active and responding to touch input may be adjusted dynamically. For example, the trackpad surface area may have an active area that can be moved between a left half of the trackpad surface area and a right half of the trackpad surface area. 
     A louver layer may be interposed between the pixel array and the trackpad surface area. The louver layer may have louvers that are tilted with respect to a surface normal associated with the trackpad surface area. The presence of the louver layer may help prevent the pixel array from appearing black when not illuminated, thereby providing the trackpad surface area of the device with an attractive appearance and an appearance that matches that of other portions of the exterior surface of the device. 
     Light from the pixel array may pass through the louver layer. The louver layer and/or other layers between the touch sensitive surface and the pixel array may have cores and claddings that are formed from materials that impart a non-black appearance (e.g., a white appearance, a gray appearance, or a non-neutral color), a desired haze (e.g., a frosted appearance), and/or other desired appearance to the touch sensitive surface area when corresponding portions of the pixel array are inactive and not emitting light. 
     Colored materials, light-scattering structures, and/or adjustable components may be incorporated into the louver layer or other portions of the layers under the trackpad surface area and above the pixel array to impart desired fixed and/or adjustable optical properties. These properties may include, for example, desired neutral or non-neutral colors, desired amounts of haze, desired amounts of opacity, and/or other desired properties that affect the appearance of the trackpad surface area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional side view of an illustrative electronic device in accordance with an embodiment. 
         FIG.  2    is a top view of an illustrative portion of an electronic device showing how the electronic device may have a touch sensitive surface area overlapping a touch sensor with reconfigurable illumination and sensing areas in accordance with an embodiment. 
         FIG.  3    is a top view of a housing for an electronic device such as a laptop computer having a touch sensor surface area with reconfigurable illumination and sensing areas in accordance with an embodiment. 
         FIGS.  4  and  5    are side views of illustrative backlights in accordance with embodiments. 
         FIG.  6    is a cross-sectional side view of a portion of an electronic device with an illuminated touch sensor area in accordance with an embodiment. 
         FIG.  7    is a cross-sectional side view of an adjustable louver structure in a louver layer in accordance with an embodiment. 
         FIG.  8    is a cross-sectional side view of a portion of an electronic device with an illuminated touch sensor area having an opaque masking layer in accordance with an embodiment. 
         FIG.  9    is top (plan) view of an illustrative opaque masking layer having a checkerboard pattern in accordance with an embodiment. 
         FIG.  10    is a top (plan) view of an illustrative opaque masking layer having a striped pattern in accordance with an embodiment. 
         FIG.  11    is a cross-sectional side view of illustrative adjustable photoluminescent layers in accordance with an embodiment. 
         FIG.  12    is a cross-sectional side view of an illustrative light guide layer having holographic optical elements in accordance with an embodiment. 
         FIG.  13    is a cross-sectional side view of an illustrative lenticular lens film disposed on a light guide layer in accordance with an embodiment. 
         FIG.  14    is a top (plan) view of a lenticular lens film of the type shown in  FIG.  13    in accordance with an embodiment. 
         FIG.  15    is a cross-sectional side view of a portion of an electronic device with an illuminated touch sensor area having an image transport layer in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may have one or more touch sensitive surface areas. A touch sensitive surface area may overlap a touch sensor that is selectively illuminated to create illuminated reconfigurable touch controls. 
     To provide the touch sensitive surface area with an attractive appearance such as an appearance that matches that of adjacent housing structures, partially transparent layers may overlap and hide the touch sensor. These partially transparent layers may have a desired neutral or non-neutral color. The partially transparent layers may include a layer of louvers covering a pixel array that can be used to provide adjustable illumination for the touch sensitive surface area. For example, adjustable illuminated icon-shaped buttons or other reconfigurable touch controls can be displayed through the partially transparent layers in some modes of operation. In other modes of operation, all illumination may be turned off. 
     The partially transparent layers are preferably sufficiently opaque to provide the touch sensitive surface area with an opaque appearance such as a non-black appearance that matches the appearance of other exterior surfaces of the device. When touch sensor illumination is turned off, for example, the outer surface of the electronic device in the touch sensor area may have a neutral color appearance such as a light gray or dark gray appearance (e.g., a silver/gray appearance that matches the appearance of a silver/gray laptop computer housing, etc.). If desired, coloration may be provided to the partially transparent layers so that the surface of the electronic device overlapping the touch sensor area has a non-neutral color (e.g., gold, rose gold, blue, green, red, etc.). 
     A cross-sectional side view of a portion of an illustrative electronic device with a touch sensor that is covered by a partially transparent layer (sometimes referred to as a partially transparent sensor cover layer or partially transparent sensor cover structure) is shown in  FIG.  1   . In general, device  10  of  FIG.  1    may be any suitable electronic device. For example, electronic device  10  of  FIG.  1    may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch or other device worn on a user&#39;s wrist, a pendant device, a headphone or earpiece device, a head-mounted device such as eyeglasses, goggles, or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, a removable battery case such as an enclosure for a head-mounted device, a removable cellular telephone battery case, a battery case for holding earbuds or other accessories, equipment that implements the functionality of two or more of these devices, or other electronic equipment. Illustrative configurations in which device  10  is a portable device such as a laptop computer of may sometimes be described herein as an example. 
     As shown in  FIG.  1   , device  10  may have a housing such as housing  12 . Housing  12  may be formed from polymer, metal, glass, crystalline material such as sapphire, ceramic, fabric, fibers, fiber composite material, natural materials such as wood and cotton, other materials, and/or combinations of such materials. The appearance of the some or all of the exterior surfaces of housing  12  may be neutral in color such as white or silver (gray) and/or may be non-neutral in color. Housing  12  may be configured to form structural layers such as housing walls. The housing walls may enclose one or more interior regions such as interior region  24  and may separate interior region  24  from exterior region  22 . Components  18  may be mounted in interior  24  (e.g., using one or more substrates such as printed circuit  20 ). Components  18  may include control circuitry (e.g., microprocessors, microcontrollers, digital signal processors, baseband processors, application specific integrated circuits, storage such as volatile and/or non-volatile memory), may include input-output devices such as sensors (e.g., ambient light sensors, fingerprint sensors, image sensors, touch sensors, force sensors, accelerometers, etc.), may include output devices such as light-emitting diodes, displays, haptic output devices, audio output devices such as speakers and tone generators, and/or may contain other input-output devices for gathering user input and environmental measurements and for providing output. If desired, components  18  may include cellular telephone transceiver circuitry, wireless local area network circuitry, and other wired and/or wireless communications circuitry. Components  18  may also include a battery for providing device  10  with power. Components 
     In the example of  FIG.  1   , interior region  24  is sandwiched between upper and lower portions of housing  12 . At rear R, housing  12  forms a rear housing wall. At front F, one or more structural layers may form a front housing wall. As an example, front F may have an inner structural layer such as layer  12 W and/or an outer structural layer such as layer  12 W. Layer  12 W and/or layer  12 W, which may sometimes be referred to as housing structures, housing walls, structural layers, etc., may be used to support layers  26 . Layers  26  may include a touch sensor that covers an area of the surface of device  10  (sometimes referred to as a touch sensor coverage area or touch sensitive surface area). Some or all of layers  26  (and layer  12 W) have partially transparent structures that provide the touch sensitive surface area with a desired outward appearance and may sometimes be referred to as partially transparent layers. 
     Inner layers such as layer  12 W may be formed from transparent or opaque material. Outer layers such as layer  12 W may be formed from transparent material (e.g., glass or clear polymer) and/or may be formed from partially transparent material (e.g., gray polymer, colored glass, and/or glass, polymer, or other material covered with a partially transparent coating, provided with haze using light-scattering coatings and/or embedded light-scattering structure, etc.). In the example of  FIG.  1   , layer  12 W has been omitted and inner layer  12 W is providing structural support for layers  26  and helping to separate exterior region  22  from interior region  24 . 
     Layers  26  may include components that emit light such as pixel array  14 P. Pixel array  14 P may have a two-dimensional array of pixels P (e.g., light-emitting pixels formed from respective light-emitting diodes or backlit adjustable-transmission pixels such as liquid crystal pixels in a thin-film liquid crystal display that receive backlight illumination from a separate backlight unit). During operation, pixel array  14 P may be adjusted to produce light that creates visible icons and other patterns of illumination on the outer surface of device  10  (e.g., on the touch sensitive surface area on front F, where these icons and other patterns of illumination can be viewed by a viewer such as user  30  who is viewing device  10  in direction  32 ) and/or some or all of the pixels in pixel array  14 P may be turned off, so that no interior illumination is visible on front F. 
     Layers  26  may include structures that form a touch sensor. As shown in  FIG.  1   , for example, layers  26  may include two-dimensional touch sensor  34 . Touch sensor  34  may be a two-dimensional capacitive touch sensor with transparent electrodes (e.g., electrodes formed from transparent conductive material such as indium tin oxide or other transparent conductive electrode material) or may be any other suitable type of touch sensor. During operation, a user may supply touch input to touch sensor  34  (e.g., using an external object that contacts the outer surface of device  10  such as finger  50  or a compute stylus). Touch sensor  34  can detect touch input to determine the location of one or more external objects such as finger  50  in the X and Y dimensions. In arrangements in which device  10  is a laptop computer, the outermost surface of device  10  at front F may correspond to the horizontal top surface of the base (lower) laptop housing in a two-part laptop computer housing (e.g., a housing that has an upper display housing that encloses a display and a lower base housing that encloses a keyboard and track pad). Touch sensor  34  in this configuration may serve as a track pad touch sensor. In devices with other form factors, touch sensor  34  may be oriented vertically and may face to the side, may be oriented horizontally while facing the rear of a device, etc. 
     Louver layer  36  and optional covering layer  38  may be provided over touch sensor  34  and pixel array  14 P to help visually obscure display  14 P while providing the exterior of device  10  on front F with a desired opaque appearance. Covering layer  38  may include one or more sublayers  38 ′. In an illustrative configuration, covering layer  38  may include a diffuser. The diffuser may be formed from a polymer layer containing light-scattering structures such as groove, pits, or other recesses, bumps, ridges, or other protrusions, and/or voids and/or other embedded particles such as inorganic dielectric particles that have refractive index values that differ from the polymer of the polymer layer in which the particles are embedded. Covering layer  38  may also have one or more textured surfaces (e.g., the outer surface of layer  38  may have texture, the inner surface of layer  38  may have texture, etc.). Layer(s) of polymer (e.g., paint) that contains colorant such as dye and/or pigment may form one or more of layers  38 ′. Layers  38 ′ may also include thin-film coating layers, thin-film interference filters formed from stacks of dielectric layers of alternating refractive index, and/or other sublayers. The presence of layer  38  in layers  26  may help provide device  10  with a desired appearance. For example, layer  38  (and/or other layers in layer  26  and/or layer  12 W) may be configured to exhibit a haze of at least 5%, at least 10%, at least 20%, at least 50%, less than 95%, or other suitable amount of haze to provide layers  26  with a hazy (frosted) appearance (e.g., a haze of at least 5%, at least 10%, at least 20%, at least 50%, less than 95%, or other suitable amount of haze). The inclusion of haze in layers  26  and/or layer  12 W above pixel array  14 P may create a hazy appearance for pixels P, but the haze of layers  26  can enhance the appearance of the touch sensitive surface area and haze in pixels P may be acceptable when using pixels P to illuminate reconfigurable touch controls as opposed to presenting high-resolution imagery of the type typically displayed on a computer display. Layer  38  (and/or other layers in layer  26  and/or layer  12 W) may also be configured to provide the touch sensitive surface area on device  10  with a desired color (e.g., a non-black neutral color such as gray or white, a non-neutral color) and that provide the touch sensitive surface area on device  10  with a desired reflectivity for ambient light (e.g., a reflectivity of at least 5%, at least 10%, at least 25%, at least 50%, at least 75%, less than 95%, less than 60%, less than 40%, etc.). 
     Louver layer  36  may be formed between layer  38  and touch sensor  34  (as an example. Louver layer  36  may have a series of parallel louvers, each of which includes a louver core  40  sandwiched between a pair of louver claddings  42 . The louvers run across the touch sensitive area parallel to the Y axis in the example of  FIG.  1   . Light  46  from pixel array  14 P may be guided through the louvers (e.g., claddings  42  may have refractive index values that are lower than cores  20  so that the louvers may form light guides in which light is guided in accordance with the principal of total internal reflection and/or may be high-reflectivity metal coatings or other structures with optical properties that help confine light in the louver cores as the light passes through layer  36 . In this way, light  46  that is emitted by the individually adjustable pixels P of layer  14 P may pass through layer  36  from the lower surface of layer  36  that faces pixel array  14 P to the opposing upper surface of layer  36  that faces away from pixel array  14 P. 
     The louvers of layer  36  may be tilted so that they extend along longitudinal axes that are tilted with respect to surface normal n of the touch sensitive surface area at the exterior surface of device  10  on front F. As shown by illustrative louver longitudinal axis  44 , louvers may be tilted away from surface normal n by a non-zero angle A. The value of A may be at least 10°, at least 20°, at least 30°, at least 40°, at least 50°, at least 60°, less than 95° less than 85°, less than 75°, less than 65°, or less than 55° (as examples). When the louvers of louver layer  36  are tilted in this way, structures in layer  36  such as claddings  42  are visible in direction  32 , so ambient light illuminating layer  36  and/or light passing through layer  36  from array  14 P can be affected by the structures of layer  36 . The selection of the materials used in forming claddings  42  and other portions of layer  36  may therefore help provide layer  36  with a desired appearance. (e.g., these structures may be configured to help impart a desired color, haze, opacity, reflectivity, etc.) 
     When adjusting the appearance of layers  26 , thin-film layers (e.g., thin-film metal coatings, thin-film layers of dielectric, etc.), colorant (e.g., dye and/or pigment), and/or light-scattering structures (texture and/or embedded particles) may be included in the structures of louver layer  36  in addition to or instead of providing layer  38  and/or layer  12 W with thin-film layers, colorant, and/or light-scattering structures. In this way, the appearance of device  10  may be adjusted by adjusting the structures of layers  36  in addition to or instead of adjusting the structures of layer  38  (and/or layer  12 W). 
     Consider, as an example, a scenario in which one or more thin-film coating layers are included in layer  36  and/or layer  38 . The thin-film layers may include metal, semiconductor, and/or dielectric. By adjusting the number of layers, the thickness of the layers, and the composition of the layers, the amount of light reflected, absorbed, and transmitted by layers  26  can be adjusted. As one example, including a thin metal layer in layers  26  may help block light and provide layers  26  with a desired partial transparency and partial mirror reflectivity. In an illustrative configuration, the reflectivity of the surface of device  10  (e.g., layer  12 W and layers  26  viewed from direction  32 ) may be 10-90%, at least 10%, at least 25%, at least 45%, less than 90%, less than 80%, less than 60%, or less than 30% (as examples), the absorption of layers  26  may be 10-90%, at least 10%, at least 25%, at least 45%, less than 90%, less than 80%, less than 60%, or less than 30% (as examples), and the transmission of layers  26  may be 10-90%, at least 10%, at least 25%, at least 45%, less than 90%, less than 80%, less than 60%, or less than 30% (as examples). These properties and other optical properties of layers  26  can also be adjusted by incorporating colorant and/or light-scattering particles into layers  26  and/or layer  12 W. As an example, the haze of layers  26  (and/or layer  12 W) can be adjusted by including light-scattering structures (e.g., embedded particles) in cores  40  and/or claddings  42  (and/or layer  38  and/or layer  12 W) so that the haze has a value of 10-90%, at least 10%, at least 25%, at least 45%, less than 90%, less than 80%, less than 60%, or less than 30% (as examples). In an illustrative configuration, cores  40  and/or claddings  42  (and/or layer  38  and/or layer  12 W) may also be provided with colorant (e.g., dye and/or pigment). The colorant may provide layer  36  (and/or layer  38  and/or layer  12 W) and therefore the touch sensitive surface area of device  10  with a neutral color (e.g., white, light gray, dark gray, or black) or may provide the touch sensitive surface area with a non-neutral color (e.g., gold, rose gold, red, blue, green, etc.). With sufficient haze in layer  36  and/or layer  38  and/or layer  12 W, device  10  may have a diffuse “frosted” outward appearance. By providing layer  36  and/or layer  38  and/or layer  12 W with sufficient reflectivity and opacity, the user will not be able to view black ink and other structures in pixel array  14 P (i.e., the outward appearance of device  10  need not be a black appearance dictated by black structures in array  14 P), but rather may have a more attractive appearance such as a silver appearance, rose gold appearance, gold appearance, white appearance, etc.). The presence of louver layer  36  may also help ensure that the color and other appearance attributes observed by user  30  when viewing device  10  in direction  32  are determined by the color attributes and other appearance attributes of cladding  42 , cores  40 , etc. This is because the tilt associated with angle A of louvers helps prevent direct viewing of pixels P along the louver cores. On the other hand, when it is desired to illuminate portions of the surface of device  10  overlapping layers  38  and  36 , this light may pass through cores  40  to adjacent portions of layer  38 . Layer  38  may include a diffuser that diffuses light  46  that reaches layer  48  through the louvers (see, e.g., diffuse light  48 , which is created when light  46  passes through a louver and, at the exit to the lover, illuminates a portion of layer  38  and causes layer  38  to scatter light  46  over a wide range of angles). Because diffuse light  48  is produced where light  46  strikes layer  38 , it will appear to user  30  that any light patterns produced by pixel array  14 P are being created directly in layer  38  (e.g., directly at the exterior surface of device  10  in arrangements in which layer  12 W is not present), rather than behind layer  38  at the surface of array  14 P. This may help create a pleasing appearance for the illuminated light patterns on device  10 . An additional layer between the pixel array  14 P and the louvers  36  may be required to properly collimate the light and improve optical efficiency of the illumination thru the layers. This may be in the form of a microlens array, dielectric film stack, Fresnel lens structure, holographic recording, or other diffractive structure that has the ability to properly redirect all angles of illumination from the pixel array directly toward (and effectively normal to) the louver layer  36 . 
     In an effort to create an illusion that the display content from pixel array  14 P is located directly on the surface of device  10 , layers  26  may optionally be provided with an image transport layer.  FIG.  15    illustrates an embodiment where layers  26  of electronic device  10  include an image transport layer  140  interposed between pixel array  14 P and the louver layer  36 . Image transport layer  140  may be formed from a coherent fiber bundle or Anderson localization layer and may be invariant along the axis of light propagation (the Z axis in the example of  FIG.  15   ). If desired, the fibers in layer  140  may be tilted with respect to the surface normal of the touch sensitive area at the exterior surface of device  10 , similar to the tilt of the louver claddings in layer  36 . As examples, the tilt of fibers with respect to the surface normal of the exterior housing surface may be at least 10°, at least 20°, at least 30°, at least 40°, at least 50°, at least 60°, less than 95° less than 85°, less than 75°, less than 65°, or less than 55°. The selection of the materials used in forming these fibers such as the color of the binding agent used to hold the fiber elements together and other portions of layer  140  may help provide layer  140  with a desired appearance (e.g., these structures may be configured to help impart a desired color, haze, opacity, reflectivity, etc.). Layer  140  may also help provide additional structural rigidity for layers  26  by providing additional thickness especially when the surrounding support layers such as layer  36  or  12 W are relatively thin. Configured in this way, image transport layer  140  may provide enhanced structural integrity while minimizing loss of light traveling from pixels P to the external housing surface of device  10 . 
     During operation, light emitted from pixels P passes vertically through layer  140  from input surface  142  to output surface  144  (e.g., due to the vertically oriented fibers in the fiber bundle forming layer  140  or the longitudinally invariant refractive index features in an Anderson localization material forming layer  140 ). The structures of  FIG.  15    may, if desired, be located along a straight section of the peripheral edge of device  10  and/or along a rounded corner section of the peripheral edge of device  10 . In some embodiments, output surface  144  may be curved (e.g., output surface  144  may exhibit a curved profile). For example, output surface  144  may have compound curvature when image transport layer  140  is being used at a corner of device  10 . 
     The example of  FIG.  15    in which there are no intervening layers between louver layer  36  and image transport layer  140  is merely illustrative. If desired, one or more of layers  84 ,  86 , and  88  may be formed between layers  136  and  140  and/or between layers  12 W and  36 . If desired, layer  12 W (e.g., an outer cover glass layer) may be completely omitted from device  10 . In yet other arrangements, one or more additional diffusive layers, light extraction layers, textured layers, adhesive layers, cover layers, or other optical control layers may be formed within layers  26  to further improve the appearance of the illuminated display content when the display is on and to match the appearance of layers  26  to that of surrounding portions of housing  12  (e.g., portions of housing  12  that do not contain layers  26 ). 
     Unlike conventional displays, display pixel array  14 P of device  10  need not include a black matrix layer. A black matrix layer is typically used to preserve or enhance the black level of a display. Omitting such black matrix from pixel array  14 P under touch sensor  34  can thus help to maintain a non-black appearance such as a neutral appearance (e.g., white, gray, or silver) or a non-neutral color (e.g., gold, red, blue, etc.). In some embodiments, a non-black masking layer such as masking layer  100  may be disposed on pixel array  14 P (see, e.g.,  FIG.  8   ). As shown in  FIG.  8   , masking layer  100  may be interposed between pixel array  14 P and touch sensor  34  (as an example). Masking layer  100  may include opaque portions such as opaque portions  101  that are aligned with non-emissive areas of pixel array  14 P. Opaque portions  101  may form openings (or windows) that are aligned with and overlap the emissive regions of pixel array  14 P.  FIG.  9    shows in suitable arrangement where masking layer  100 A forms a checkerboard pattern having openings  102  aligned with corresponding pixels in the display module.  FIG.  10    shows another suitable arrangement where masking layer  100 B includes opaque stripe portions  101  that form openings (or channels)  104  aligned with corresponding rows or columns of pixels in the display module. The patterns of  FIGS.  9  and  10    are merely illustrative. In general, masking layer  100  may have opaque portions forming any regular or irregular pattern that at least partially overlap with the non-emissive areas of pixel array  14 P. 
     As described above, masking layer  101  should not be black to help prevent pixel array  14 P from appearing black when not illuminated (e.g., to provide the trackpad surface area of device  10  with an attractive appearance and an appearance that matches that of other portions of the exterior surface of device  10 ). To accomplish this, masking layer  101  may be formed using white opaque material such as titanium dioxide, titanium nitride, white polymer, white paint, or other suitable white material. Layer  101  might therefore sometimes be referred to as a non-black opaque masking layer such as a white matrix layer. Using a white masking layer  101  might be suitable for device  10  with a white exterior housing. If device  10  has an exterior housing of a different color (e.g., gray, black, gold, red, blue, green, etc.), masking layer  101  may be formed from opaque material having a color that helps match the outward appearance of surrounding portions of the device housing in terms of color, texture, reflectivity, haze, etc. 
     The light patterns produced by pixel array  14 P may correspond to icons, reconfigurable button shapes, notifications, and/or other visual elements. Touch sensor  34  can receive input from these illuminated areas and from non-illuminated regions of the touch sensitive surface area. Consider, as an example, the arrangement of device  10  of  FIG.  2   . In this configuration, a portion of the exterior of device  10  forming a touch sensitive surface area may be overlapped by layers  26 . During operation of device  10 , the control circuitry in device  10  can use pixel array  14 P to display illumination that creates illuminated touch controls  60  on the surface of device  10  (e.g., on layer  38  of layers  26 ). The illuminated touch controls can be created dynamically (e.g., by adjusting pixels P to produce a desired illumination pattern on layer  38 ). This allows the touch controls to be animated, to move in response to user input, to be adjusted to accommodate different modes of operation, to change as a function of which software application is running on device  10 , etc. Because the illuminated touch controls can be adjusted (e.g., in shape, location, functionality, etc.), the illuminated touch controls may sometimes be referred to as reconfigurable touch controls, reconfigurable illuminated touch controls, reconfigurable illuminated touch sensor regions, etc.). 
     In the example of  FIG.  2   , the right-hand illuminated touch control is a sliding button. As shown in  FIG.  3   , this touch control may include sliding button portion  60 ′, which can be moved up and down parallel to the Y axis as a user drags finger  50  up and down parallel to the Y axis (as an example). In general, reconfigurable touch controls for device  10  may have any suitable fixed and/or adjustable visual appearance (e.g., different portions that can move in response to user touch input, portions that can change color, portions that can change from solid to blinking, areas that exhibit changeable brightness, fixed icon shapes, text labels, and/or other features). If desired, the overall layout and type of controls that are presented can also be adjusted depending on the mode of operation, based on user input, etc. 
     The portion of touch sensor  34  that is used in gathering touch input may be adjusted depending on the location and type of illuminated touch controls that are being presented. As an example, all portions of touch sensor  34  except those in the immediate vicinity of the touch controls may be deactivated to prevent inadvertent touch input or, in an alternative arrangement, all or some of the area of touch sensor  34  other than the portion of touch sensor  34  that is in the immediate vicinity of the touch controls may also remain active (e.g., to receive track pad input separate from touch input provided to the reconfigurable controls). 
     Consider, as an example, device  10  of  FIG.  3   . In the example of  FIG.  3   , device  10  is a laptop computer.  FIG.  3    is a top view of the base housing portion of housing  12 . Keyboard  62  and track pad  70  may be formed on the exposed top surface of the base housing, so that these input devices may be accessed by a user. For example, keyboard  62  may be a QWERTY keyboard containing alphanumeric keys (e.g., movable mechanical keys that each have movable key member that actuates a corresponding switch or other keys) that a user may use to enter text by typing. Keyboard  62  may include function keys, numeric keys, and/or other keyboard keys. Track pad  70 , which may sometimes be referred to as a touch pad or touch controller, may have a two-dimensional capacitive touch sensor such as touch sensor  34  of  FIG.  1    that forms a touch sensitive surface area on housing  12 . Touch sensor  34  and the other layers in layers  26  of  FIG.  1    (e.g., pixel array  14 P, louver layer  36 , etc.) may have any suitable shape. In the example of  FIG.  3   , layers  26  have a rectangular outline with a width that is equal to or nearly equal to the width of keyboard  62  (e.g., the width of the rectangular region that includes layers  26  may be equal to that of the width of keyboard  62  within +/−20%, within +/−10%, or within +/−5%). If desired, the touch area and pixel array  14 P may also extend to include keyboard region  62 , with the keyboard “key elements” being created dynamically by pixel array  14 P and key presses being detected by the touch sensor. 
     During operation, illuminated touch controls  60  may be displayed on some or all of layers  26  (e.g., in some or all of the surface area of track pad  70 ). Track pad  70  may or may not be visible to the user. Touch sensor  34  may likewise be configured to be active over some or all of the area consumed by track pad  70 . If desired, the touch and/or illumination functions of layers  26  in track pad  70  may be configured differently in different modes of operation. 
     For example, in a first mode of operation, touch sensor  34  may be configured to sense touch input over the entire surface of track pad  70  (e.g., all capacitive touch sensor electrodes in sensor  34  may be active and used in monitoring for touch input), whereas in other modes of operation, only a subset of the surface of track pad  70  is active and remaining portions of the surface of track pad  70  are inactive. For example, in a second mode of operation, track pad  70  may be active in left area  64  but not in right area  68 . In this second mode of operation, an outline of the left area  64  might be displayed on some or all of layers  26  and a user may supply touch input to area  64  (e.g., track pad input to control a cursor on a display in device  10 , etc.), but any touch input to area  68  on the right side of track pad  70  will be ignored by device  10 . Similarly, in an illustrative third mode of operation, track pad  70  may be configured so that area  68  on the right of track pad  70  is active, whereas area  64  on the left of track pad  70  is inactive. In this third mode, an outline of the right area  68  might be displayed on some or all of layers  26  and the user may supply touch input to area  68 . Any touch input on the left of track pad  70  (e.g., in area  64 ) will be ignored. One or more additional modes may be supported, if desired. For example, a fourth mode of operation may be supported in which only center portion  66  of track pad  70  is active and remaining portions to the left and right of this central area are inactive. In this fourth mode, an outline of the center area  66  might be displayed on some or all of layers  26  and the user may supply touch input to area  66 . 
     Selectable illuminated options (e.g., buttons, sliders, knobs, and/or other reconfigurable illuminated touch controls) may be displayed in the active area of track pad  70 . If desired, portions of track pad  70  that might otherwise be inactive (e.g., left area  64  in the illustrative third mode of operation) may be active so long as these portions directly coincide with an illuminated touch control. For example, area  64  may be inactive in the third mode except where a selectable set of illuminated icons are located. Selectable buttons may also be present within the active area of track pad  70  that is being used to gather track pad input such as cursor positioning input that is not generally associated with illuminated controls. 
     As the foregoing example demonstrates, the active touch sensing regions and illuminated controls of the touch sensitive surface area of device  10  that is covered with layers  26  (e.g., track pad  70  in the example of  FIG.  3   ) may be dynamically reconfigured. Different illuminated touch controls and/or active touch areas may be present in different contexts. For example, different patterns of illuminated touch controls and active touch areas may be used in response to the use of different software programs (e.g., different applications running on the control circuitry of device  10 ), may be used in response to changing operating modes within a software program (e.g., transitioning between a review mode and an edit mode in a drawing program or word processing program, etc.), may be used in response to the position and/or relative orientation of different portions of housing  12  (e.g., depending on whether the lid of a laptop computer is open or closed, may be used depending on whether a tablet computer is operated in portrait or landscape mode, etc.), and/or may be used in response to other suitable conditions. The example of  FIG.  3    in which track pad  70  is reconfigurable between several different operating modes is illustrative. 
     To produce backlight illumination for pixels P in pixel array  14 P, pixel array  14 P may be provided with a backlight unit (sometimes referred to as a backlight or backlight structures). Illustrative backlight units for device  10  are shown in  FIGS.  4  and  5   . In the example of  FIG.  4   , backlight  72  has a light guide layer  78 . Light guide layer  78  may sometimes be referred to as a waveguide. Light  74  is emitted into the edge of light guide layer  78  by light source  76 . Light guide layer  78  may be a layer of polymer (e.g., a flexible polymer film or rigid polymer plate), glass, or other transparent substrates capable of guiding light via the principle of total internal reflection. Light source  76  may include one or more light-emitting devices such as laser diodes, light-emitting diodes, micro LEDs, micro-projectors, microelectromechanical system (MEMS)-based displays, digital micromirror device (DMD) displays, liquid crystal on silicon (LCoS) displays, computer-generated holography (CGH) displays, or spatial light modulator displays that can directly display content using the light guide layer  78 . These light-emitting devices may be mounted along one or more edges of light guide layer  78 . Light source  76  may emit infrared, visible, and/or ultraviolet light. This light (light  74 ) may travel laterally within light guide layer  78  in accordance with the principle of total internal reflection. Light guide layer  78  may include light-scattering structures that scatter some of this light (e.g., light  74 ′ in the example of  FIG.  4   ) outwardly to serve as backlight for pixel array  14 P or for directly outputting display content. The light-scattering structures may include bumps, ridges, and/or other protrusions on one or both surfaces of layer  78 , may include pits, grooves, and/or other recesses on one or both surfaces of layer  78 , may include embedded light-scattering particles such as titanium dioxide particles or other inorganic dielectric particles having a refractive index that varies from that of layer  78 , and/or may include embedded fluid-filled bubbles. If desired, a reflector such as reflector  80  (e.g., a polymer film with a stack of alternating-refractive-index layers that form a thin-film interference filter mirror, a reflective layer of white ink, and/or other reflective materials) may be included in backlight  72  to help recycle scattered light that has been scattered out of layer  78  in the downwards (−Z) direction. 
     If desired, light guide (waveguide) layer  78  may optionally include holographic (diffractive) optical elements.  FIG.  12    shows a cross-sectional side view of light guide layer  78  having holographic optical element  124  interposed between substrates  120  and  122 . Holographic optical element  124  may include holographic media such as photopolymers, gelatin such as dichromated gelatin, silver halides, holographic polymer dispersed liquid crystal, or other suitable volume holographic media. Holographic recordings (e.g., holographic phase gratings sometimes referred to herein as holograms) may be stored in the holographic media. The holographic media may sometimes be referred to herein as grating media. A holographic recording may be stored as an optical interference pattern (e.g., alternating regions of different indices of refraction) within a photosensitive optical material such as the holographic media. The optical interference pattern may create a holographic phase grating that, when illuminated with a given light source, diffracts light to create a three-dimensional reconstruction of the holographic recording. The holographic phase grating may be a non-switchable diffractive grating that is encoded with a permanent interference pattern or may be a switchable diffractive grating in which the diffracted light can be modulated by controlling an electric field applied to the holographic recording medium. Multiple holographic phase gratings (holograms) may be recorded within (e.g., superimposed within) the same volume of grating medium if desired. The holographic phase gratings may be, for example, volume holograms in the grating medium. 
     Holographic optical element  124  may include a set of diffractive gratings configured to diffract light  126  traveling through light guide layer  78  out of light guide layer  78  towards a user&#39;s eye, as shown by exiting light ray  126 ′. In this example, holographic optical element  124  may include transmissive gratings. This is merely illustrative. Light guide layer  78  may include reflective gratings and/or transmissive gratings. 
     In some embodiments, additional optical elements such as lenticular films may be disposed on top of light guide layer  78  (see, e.g.,  FIG.  13   ). As shown in  FIG.  13   , lenticular lens film  130  (sometimes referred to as a stereoscopic lens film, light redirecting film, or lens film) may be formed over light guide layer  78 . Lenticular lens film  130  includes lenses  134  and a base film portion  132  (e.g., a planar film portion to which lenses  134  are attached). Lenses  134  may be lenticular lenses that extend along respective longitudinal axes (e.g., axes that extend into the page parallel to the Y-axis). Lenses  134  may be referred to as lenticular elements, lenticular lenses, optical elements, etc. 
     The lenticular lenses may redirect light emitted from light guiding layer  78  or other overlapping display pixels (see, e.g., display pixels P of  FIG.  1    or  FIG.  6   ) to enable stereoscopic viewing of the display pixel array. Consider the example of the display being viewed by a viewer with a first eye (e.g., a right eye)  48 - 1  and a second eye (e.g., a left eye)  48 - 2 . Light  138  from light guide layer  78  is directed by the lenticular lens film  130  towards left eye  48 - 2 , whereas light  136  from light guide layer  78  is directed by the lenticular lens film  130  towards right eye  48 - 1 . Configured in this way, the viewer&#39;s right eye  48 - 1  and left eye  48 - 2  may see slightly different images projected from the display. Consequently, the viewer may perceive the received images as a single three-dimensional image floating above the surface of the device housing. 
       FIG.  14    is a top view of illustrative lenticular lens film  132  of the type shown in  FIG.  13   . As shown in  FIG.  14   , elongated lenses  134  extend across the display parallel to the Y-axis. For example, the cross-sectional side view of  FIG.  13    may be taken looking in direction  139 . Lens film  130  may include any desired number of lenticular lenses  134  (e.g., more than 10, more than 100, more than 1,000, more than 10,000, etc.). In the example of  FIG.  14   , the lenticular lenses  134  extend perpendicular to the upper and lower edge of the display panel. This arrangement is merely illustrative, and the lenticular lenses may instead extend at a non-zero, non-perpendicular angle (e.g., diagonally) relative to the display panel if desired. With the arrangement of  FIG.  14   , the lenticular lenses  134  split the display into distinct viewing zones along the X-axis. 
     In the example of  FIG.  5   , backlight  72  is a direct-lit backlight having a two-dimensional array of light sources  76  (e.g., a two-dimensional array of light-emitting diodes and/or lasers) that produce backlight  74 ′ directly. Light sources  76  of  FIG.  5    may be mounted on a substrate such as printed circuit  82  (e.g., a flexible printed circuit formed from a bendable sheet of polyimide or other flexible layer of polymer or a rigid printed circuit formed from fiberglass-filled epoxy or other rigid printed circuit board substrate material). Light sources  76  of  FIG.  5    may, if desired, be individually controlled (e.g., so that backlight  74 ′ is only produced in areas of pixel array  14 P where this backlight is being used to illuminate reconfigurable touch controls). 
     Backlights such as backlights  72  of  FIGS.  4  and  5    may be used to backlight arrays of pixels P in pixel array  14 P such as liquid crystal pixel arrays. A liquid crystal pixel array may be formed from a liquid crystal layer sandwiched between a thin-film transistor layer and a color filter layer. The thin-film transistor layer may have a two-dimensional array of individually controlled pixel circuits each of which has electrodes to control an associated pixel-sized portion of the liquid crystal layer. Polarizers may be formed on the upper and lower surfaces of the pixel array (e.g., so that the color filter layer and thin-film transistor layer are sandwiched between the polarizers). With this arrangement and other suitable liquid crystal pixel array arrangements, each pixel may be individually adjusted to control its light transmission. By adjusting the transmission of each liquid crystal pixel, a desired illumination pattern for the reconfigurable touch controls on the touch sensitive surface area can be produced. In general, any suitable type of adjustable pixels may be used in forming a backlit pixel array. The use of a two-dimensional array of liquid crystal pixels to form pixel array  14 P is illustrative. 
     If desired, backlight  72  can be omitted by providing pixel array  14 P with an array of light-emitting pixels P. Pixels P may be, for example, light sources such as laser diodes or light-emitting diodes. Light-emitting diode pixels may each have a light-emitting diode such as a thin-film organic light-emitting diode or a light-emitting diode formed from a crystalline semiconductor die. An array of pixels P for providing device  10  with the ability to display images may also be implemented using other display technologies. For example, pixel array  14 P may be implemented using a scanning display design such as a scanning laser, may be implemented using a display projector (e.g., a projection source such as a digital light projector, a liquid-crystal-on silicon projector, or other projector). 
     In some configurations, ultraviolet backlight is produced by backlight  72  (e.g., when light sources  76  of  FIG.  4    or  FIG.  5    are ultraviolet light sources such as ultraviolet lasers or light-emitting diodes). An example of this type of configuration is shown in  FIG.  6   . Backlight  72  of  FIG.  6    produces ultraviolet light that passes through the pixels P of pixel array  14 P that have been placed into a fully or partially transparent state (see, e.g., partially or fully transparent pixels P′ of  FIG.  6   ). After passing through selected pixels P′ in pixel array  14 P, ultraviolet light  74 ′ may pass through optional filter  84 . Filter  84  may be a thin-film interference filter that is formed from a stack of dielectric layers of alternating refractive index and/or other dielectric layers with refractive index values and thicknesses configured to provide filer  84  with desired spectral characteristics for absorption, reflection, and transmission. In an illustrative arrangement, filter  84  is configured to pass ultraviolet light  74 ′ while absorbing and/or reflecting visible light. The optical characteristics of filter  84  may be used in adjusting the outward appearance of device  10  in the touch sensing surface area of housing  12  (e.g., the area of housing  12  overlapped by layer  12 W and layers  26 ). If desired, pixel array  14 P may be formed from an array of ultraviolet organic light-emitting diodes or ultraviolet crystalline light-emitting diode dies that are tuned to emit ultraviolet light. In this type of arrangement, ultraviolet light from pixel array  14 P need not pass through adjustable-transmission pixels and backlight  72  may be omitted. 
     Layers  26  may include louver layer  36  and optional layers above and below louver layer  36  such as layers  86  and  88 . Touch sensor  34  may be located in layer  86  or layer  88 . Layer  88  (or, in some embodiments, layer  86  or even layer  12 W) may also include a photoluminescent layer or material such as a phosphor layer or other layer of material that exhibits fluorescence when exposed to ultraviolet light  74 ′. The photoluminescent layer may be located above or below touch sensor  34 . In some embodiments, louver layer  36  may be omitted. Configurations in which louver layer  36  is present may sometimes be described as an example. 
     If desired, texture, light-scattering particles, colorant (e.g., dye and/or pigment), and/or other materials may be incorporated into layers  26 . For example, layer  36 , and/or other layers over array  14 P (e.g., layer  86  and/or layer  12 W) may be provided with materials that absorb and/or reflect visible light, thereby adjusting the color, texture, and other visual attributes of device  10  (e.g., so that the touch sensitive surface of device  10  that is covered by layers  26  has an outward appearance that matches that of surrounding portions of housing  12  in color, texture, reflectivity, etc.). 
     In configurations in which layer  88  includes a photoluminescent layer that fluoresces under ultraviolet illumination, the photoluminescent layer may be covered by a filter coating that blocks ultraviolet ambient light while passing visible light. The filter may be a thin-film interference filter that is formed from a stack of dielectric layers of alternating refractive index and/or other dielectric layers with refractive index values and thicknesses configured to provide the filter with desired spectral characteristics for absorption, reflection, and transmission. In an illustrative arrangement, the filter of layer  88  is configured to block ultraviolet light such as ultraviolet ambient light, so that ultraviolet ambient light does not pass through the filter to the photoluminescent layer. This prevents the photoluminescent layer from fluorescing due to exposure from ambient light. The filter of layer  88  may be configured to pass some or all visible light, so that layer  36  may be viewed by a user (e.g., so that colored structures, structures with desired haze, and/or structures with other desired optical characteristics that are formed in layer  36  and/or other portions of layers  26  may be viewed from the exterior of device  10 ). 
     In general, any suitable portions of layers  26  may be provided with desired visible attributes such as a desired color, desired texture, desired haze, etc.). As an example, in scenarios in which the photoluminescent layer is located in layer  88 , color, texture, haze, and/or other desired properties may be imparted to portions of layer  36 , layer  86 , and/or layer  84 , which are visible through layer  88 . Layer  88  (e.g., the filter coating on the photoluminescent layer in layer  88 ) may also be provided with a desired color, texture, and/or other desired visual properties. These visual properties of layers  26  may be selected so that layers  26  have an appearance that matches that of surrounding portions of housing  12  (e.g., portions of housing  12  that do not contain layers  26 ). 
     Housing  12  may be configured to form a housing for a laptop computer (e.g., in a scenario in which layer  26  overlap a reconfigurable trackpad and/or a reconfigurable keyboard), may be configured to form a housing for a cellular telephone, a housing for other portable devices, a housing for a removable case, cover, or folio, a housing for a battery case for holding earbuds or other accessories, housing structures for other electrical components, and/or other structures for electronic devices. 
     During operation, ultraviolet light that passes from backlight  72  through adjustable-transmission pixels in array  14 P or that is emitted directly by ultraviolet-light-emitting diodes or lasers in pixel array  14 P in a scenario in which backlight  72  is omitted reaches the photoluminescent layer and generates visible light. In an illustrative embodiment, layer  88  contains the photoluminescent layer and light  46  (e.g., ultraviolet light  74 ′ that is passing through optional louver layer  36 ) strikes the photoluminescent layer and creates corresponding visible light (e.g., white visible light, as an example). The pattern of ultraviolet light that strikes the photoluminescent layer determines the corresponding pattern of visible light that is created. As with the other illustrative arrangements for layers  26 , the pattern of visible light that is created may correspond to a notification, a reconfigurable touch control, or other visual output. 
     In arrangements in which the photoluminescent layer is located in layer  88 , the illuminated pattern that is created in the photoluminescent layer will appear close to the outermost surface of device  10 . Layer  36  in this type of configuration may be transparent to ultraviolet light so that the ultraviolet light can reach the photoluminescent layer. In arrangements in which the photoluminescent layer is located in layer  86 , visible light from the photoluminescent layer that is produced when ultraviolet light strikes the photoluminescent layer may pass through layer  36 . 
     The desired appearance that is produced for layers  26  may include a desired neutral or non-neutral color, a desired reflectivity, a desired opacity, a desired haze, etc. This desired appearance may match the appearance of surrounding portions of device  10  (e.g., adjacent portions of housing  12  that do not overlap layers  26  may have a color, reflectivity, haze, texture, and/or other attributes that are the same as or nearly the same as the corresponding color, reflectivity, haze, texture, and/or other attributes of the portion of device  10  overlapping layers  26 ). 
     Optional internal supporting layer(s) and/or external supporting structures such as optional outer layer  12 W may overlap layer  88 . As described in connection with  FIG.  1   , layer  12 W may be a housing wall in housing  12  or other structural layer that is used to support layers  26 . If desired, layer  12 W may have a first area that coincides with the touch sensitive surface area of layers  26  and may have a second area that is not touch sensitive (e.g., layer  12 W may overlap the top of a laptop base housing so that a given portion of layer  12 W overlaps a trackpad region and a remaining portion does not overlap the trackpad region). Layer  12 W may be formed from polymer, glass, crystalline material such as sapphire, and/or other suitable materials and may be clear, may be partially transparent, may have a neutral color (e.g., gray), may have a non-neutral color (e.g., gold, red, blue, green, etc.), may or may not have texture and/or light-scattering particles that create haze, and/or may have other suitable attributes that help provide the exterior of device  10  that layers  26  with a desired appearance. 
     The outward appearance of device  10  over layers  26  may also be adjusted by providing layer  36 , and/or other layers  26  with desired optical properties (e.g., by providing the louver cores and/or claddings with light-scattering particles, dye, pigment, and/or other colorant, surface texture, one or more optional coating layers with desired optical characteristics, etc.). Touch sensor functionality may be included in layers  26  of  FIG.  6   , if desired (e.g., by incorporating touch sensor  34  of  FIG.  1    into layers  26  above or below louver layer  36 ). In this way, the appearance of layer  12 W and/or the layers under layer  12 W such as louver layer  36  and/or other layers  26  may create a desired visual appearance for device  10 . For example, layers  26  may be sufficiently transparent to allow light  46  to exit device  10  and thereby form notifications or reconfigurable illuminated touch controls visible on the surface of layers  26 , while being provided with an attractive appearance (e.g., a desired non-neutral color or a partially transparent neutral shade such as light or dark grey) where internal illumination from layers  26  is not present. 
     In yet other embodiments, layer  88  may include one or more layers of colloidal semiconductor nanocrystalline particles, sometimes referred to as quantum dots. Similar to other photoluminescent materials, quantum dots can respond to short wavelength illumination in the ultraviolet or near-ultraviolet range. When a quantum dot is illuminated by ultraviolet light, an electron in the quantum dot jumps from the valence band to the conductance band. The excited electron will drop back to the valence band, releasing its energy via an emission of light. Depending on their atomic structure, size, and/or geometry, a quantum dot particle can, when excited using ultraviolet (or near-UV) light, emit red, green or blue light. For example, smaller quantum dots are configured to emit blue (bluish) light, whereas larger quantum dots are configured to emit red (reddish) light. Medium sized quantum dots are configured to emit green (greenish) light. Quantum dots are small enough such that layer  88  would appear transparent to the human eye and their resulting illumination would appear near or directly on the surface of the device housing. 
     In general, photoluminescent material such as phosphors and quantum dots react equally to a given excitation of ultraviolet light (or near-UV light). Thus, using a single illumination source to excite the photoluminescent material in layer  88  would generate a single color or a constant mix of several colors.  FIG.  11    illustrates another embodiment of layer  88  that includes multiple layers of quantum dots configured to generate a full color RGB image from a single illumination source. As shown in  FIG.  11   , layer  88  may include a first quantum dot layer  110 B having blue quantum dots  112 B disposed between adjacent conductive layers  114 , a second quantum dot layer  110 G having green quantum dots  112 G disposed between adjacent conductive layers  114 , and a third quantum dot layer  110 R having red quantum dots  112 R disposed between adjacent conductive layers  114 . 
     Quantum dots can be quenched using an applied electric field, which causes the quantum dots to ignore the incoming illumination  116  (e.g., application of an electric field can prevent the quenched quantum dots from responding to incoming ultraviolet excitation light source  116 ). In  FIG.  11   , red quantum dots  112 B can be selectively quenched by applying a non-zero voltage V 1  across conductive plates  114  to generate an electric field in layer  110 B; green quantum dots  112 G can be selectively quenched by applying a non-zero voltage V 2  across conductive plates  114  to generate an electric field in layer  110 G; and red quantum dots  112 R can be selectively quenched by applying a non-zero voltage V 3  across conductive plates  114  to generate an electric field in layer  110 R. When none of the layers are quenched, all three layers will be excited to generate white light. One or more of layers  110 B,  110 G, and  110 R can be sequentially quenched to generate a full color RBG image using a single illumination light source (e.g., ultraviolet light). As an example, quenching only layers  110 G and  110 R will allow layer  110 B to emit blue light. As another example, quenching only layers  110 R and  110 B will allow layer  110 G to emit green light. As yet another example, quenching only layer  110 B will allow layers  110 G and  110 R to collectively emit yellow light. 
     If desired, the louvers of louver layer  36  may be adjustable. As shown in  FIG.  7   , for example, louver claddings  42  (or coatings on portions of claddings  42 ) may form electrodes that are used to apply adjustable electric fields across louver cores  40 . In the example of  FIG.  7   , core  40 ′ has a pair of associated electrodes that are electrically connected to terminals  90  and  92 , respectively. Louver cores such as core  40 ′ (and/or some or all of claddings  42 ) may contain a material that is adjusted in response to changed electric field strength (e.g., guest-host liquid crystal material, electrophoretic ink, polymer dispersed liquid crystal material, electrochromic material, and/or other material that exhibits adjustable optical properties such as an adjustable absorption spectrum, an adjustable transmission spectrum, and/or an adjustable reflection spectrum that varies as a function of applied electric field and/or an adjustable haze and/or an adjustable polarization). By providing the core material and/or cladding material of layer  36  with material(s) having adjustable optical properties, the appearance of layer  36  and therefore the exterior of device  10  overlapping layers  26  may be adjusted (e.g., to exhibit a desired neutral or non-neutral color, to exhibit a desired haze, to exhibit a desired transmission, etc.). Adjustable louvers in louver layer  36  may be adjusted separately from adjustments made to pixels P in pixel array  14 P and/or louver adjustments may be made in place of adjustments to pixels P (e.g., in arrangements in which the electrodes in the louvers are pixelated). As an example, pixel array  14 P may be omitted and louvers  36  may contain an array of adjustable louvers that serve as adjustable pixels. The adjustable pixels of louvers  36  can be adjusted to create desired patterns of illumination such as illumination patterns associated with reconfigurable touch controls. Backlight illumination for adjustable louvers may be provided by backlight  72  (see, e.g.,  FIGS.  4  and  5   ). 
     Device  10  may be operated in a system that uses personally identifiable information. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     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: 20220318
Publication Date: 20241126
Grant Date: 20241126
Priority Date: 20210401
Inventors: Segler, Jr., Dana F
CHEN, WEI
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B6/0043", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133617", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B30/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133617", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0043", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B30/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133617", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B30/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0043", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 93566850