PATENT DOCUMENT

Publication Number: US-10512157-B2
Application Number: US-201715713378-A
Country: US
Kind Code: B2

Title: Electronic devices having ambient light sensors with electrostatic shields

Abstract:
An electronic device may be provided with a display. An opaque layer may be formed on an inner surface of a display cover layer in an inactive area of the display. An optical component window may be formed from the opening and may be aligned with an ambient light sensor such as a color ambient light sensor. The color ambient light sensor may have photodetectors on a light detector integrated circuit. Electrostatic shielding may be incorporated into the color ambient light sensor to prevent perturbations in the output of the color ambient light sensor due to the presence of electrostatic charge in the vicinity of the optical component window. The shielding may include a grounded shield layer on a surface of an ambient light sensor support structure that faces the display cover layer and may include a transparent shield layer overlapping the photodetectors.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a transparent member having an optical component window; 
 a support structure having a surface facing the transparent member; 
 a light detector integrated circuit coupled to the support structure; 
 an electrostatic shield layer on the surface that is configured to shield the light detector; and 
 optical components in the support structure between the light detector and the transparent member. 
 
     
     
       2. The electronic device defined in  claim 1  further comprising a signal path that is configured to short the electrostatic shield layer to a fixed potential. 
     
     
       3. The electronic device defined in  claim 2  wherein the optical components comprise a light diffuser. 
     
     
       4. The electronic device defined in  claim 3  wherein the optical components comprise a visible-light-transmitting-and-infrared-light-blocking filter. 
     
     
       5. The electronic device defined in  claim 4  wherein the optical components comprise a light guide interposed between the light diffuser and the visible-light-transmitting and-infrared-light-blocking filter. 
     
     
       6. The electronic device defined in  claim 2  wherein the support structure comprises a plastic support having an interior in which the optical components are mounted and having an exterior surface on which the signal path is formed. 
     
     
       7. The electronic device defined in  claim 2  wherein the light detector integrated circuit comprises a plurality of photodetectors overlapped by respective color filters of different colors. 
     
     
       8. The electronic device defined in  claim 7  further comprising:
 a display having a brightness; and 
 control circuitry configured to adjust the brightness based on information from the light detector integrated circuit. 
 
     
     
       9. The electronic device defined in  claim 8  wherein the photodetectors include photodetectors corresponding to a clear channel and to a channel of a given color and wherein the control circuitry is configured to adjust the brightness at least partly in response to a ratio of an output from the clear channel to an output from the channel of the given color. 
     
     
       10. The electronic device defined in  claim 1  wherein the light detector integrated circuit includes photodetectors and wherein the light detector integrated circuit further comprises an additional electrostatic shield layer covering the photodetectors. 
     
     
       11. The electronic device defined in  claim 10  wherein the additional electrostatic shield layer comprises a layer of transparent conductive material. 
     
     
       12. The electronic device defined in  claim 11  further comprising a signal path configured to short the layer of transparent conductive material to a fixed potential. 
     
     
       13. An electronic device, comprising:
 an array of pixels configured to display images; 
 a display cover layer that overlaps the pixels; 
 an optical component window in a portion of the display cover layer through which ambient light passes; and 
 a color ambient light sensor aligned with the optical component window, wherein the color ambient light sensor includes:
 an opaque support structure; 
 a light detector integrated circuit that is at least partially surrounded by the opaque support structure, wherein the light detector integrated circuit has a plurality of photodetectors each overlapped by a color filter that is configured to pass a different respective band of visible light wavelengths; and 
 an electrostatic shield configured to shield the light detector integrated circuit from signal perturbations. 
 
 
     
     
       14. The electronic device defined in  claim 13  wherein the opaque support structure has a surface facing the display cover layer and wherein the electrostatic shield comprises a metal layer on the surface that is shorted to a fixed potential. 
     
     
       15. The electronic device defined in  claim 14  further comprising a layer of adhesive interposed between the surface and the display cover layer. 
     
     
       16. The electronic device defined in  claim 13  wherein the electrostatic shield comprises a transparent conductive layer on the light detector integrated circuit that overlaps the photodiodes and is shorted to a fixed potential. 
     
     
       17. The electronic device defined in  claim 16  wherein the opaque support structure has a surface facing the display cover layer and wherein the electronic device further comprises a metal layer on the surface that is shorted to the fixed potential. 
     
     
       18. The electronic device defined in  claim 13  further comprising:
 a flexible printed circuit with metal traces; 
 a signal path on the support structure that shorts the electrostatic shield to a trace at a fixed potential in the metal traces. 
 
     
     
       19. An electronic device, comprising:
 a display having a display cover layer; 
 an ambient light sensor window in the display cover layer; and 
 an ambient light sensor configured to receive ambient light through the ambient light sensor window, wherein the ambient light sensor comprises:
 a light detector; and 
 a ring of metal at a fixed potential that surrounds the ambient light sensor window and that faces an inner surface of the display cover layer, wherein the ring of metal is configured to serve as an electrostatic shield for the light detector. 
 
 
     
     
       20. The electronic device defined in  claim 19  wherein the light detector comprises:
 a plurality of photodetectors; and 
 a layer of transparent conductive material at the fixed potential that overlaps the photodetectors.

Description:
FIELD 
     This relates generally to electronic devices, and, more particularly, to electronic devices with optical components such as ambient light sensors. 
     BACKGROUND 
     Electronic devices such as laptop computers, cellular telephones, and other equipment are sometimes provided with optical components. For example, an electronic device may have an ambient light sensor for gathering measurements of ambient light levels. Ambient light information may be used in adjusting screen brightness during operation of an electronic device. If ambient light levels brighten, for example, display brightness can be increased to ensure that content is not obscured on a user&#39;s display. 
     Sensors such as ambient light sensors can be adversely affected by electrostatic charge when a user touches an electronic device near to the sensors. If care is not taken, signal perturbations from the presence of a user&#39;s finger can create noise in an ambient light sensor output signal. This can lead to undesired fluctuations in screen brightness. 
     SUMMARY 
     An electronic device may be provided with a display mounted in a housing. The display may have an array of pixels that form an active area and may have an inactive area that runs along an edge of the active area. An opaque layer may be formed on an inner surface of a display cover layer in the inactive area of the display or may be formed on another transparent layer in the electronic device. An optical component window may be formed from the opening and may be aligned with an ambient light sensor such as a color ambient light sensor. The color ambient light sensor may have photodetectors on a light detector integrated circuit. 
     Electrostatic shielding may be incorporated into a color ambient light sensor to prevent perturbations in the output of the color ambient light sensor due to the presence of electrostatic charge in the vicinity of the optical component window. The shielding may include a shield layer on a surface of an ambient light sensor support structure that faces the display cover layer and may include a transparent shield layer overlapping the photodetectors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative electronic device with a display having optical component windows overlapping optical components such as an ambient light sensor in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of an illustrative electronic device that has optical components such as a light source, image sensor, and ambient light sensor in accordance with an embodiment. 
         FIG. 4  is a diagram showing how a user&#39;s finger may be capacitively coupled to an ambient light sensor integrated circuit through a display cover layer in an electronic device in accordance with an embodiment. 
         FIG. 5  is a circuit diagram showing how the output signal from a photodetector in a light detector integrated circuit may be perturbed due to capacitive coupling from a user&#39;s finger in an electronic device in accordance with an embodiment. 
         FIG. 6  is a side view of an illustrative ambient light sensor with shielding in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative light detector integrated circuit with shielding in accordance with an embodiment. 
         FIG. 8  is a top view of an illustrative light detector integrated circuit with shielding in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A schematic diagram of an illustrative electronic device of the type that may be provided with an optical component such as an ambient light sensor is shown in  FIG. 1 . Electronic device  10  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 wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses 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, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     As shown in  FIG. 1 , electronic device  10  may have control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  16  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc. 
     Device  10  may have input-output circuitry such as input-output devices  12 . Input-output devices  12  may include user input devices that gather user input and output components that provide a user with output. Devices  12  may also include communications circuitry that receives data for device  10  and that supplies data from device  10  to external devices. Devices  12  may also include sensors that gather information from the environment. 
     Input-output devices  12  may include one or more displays such as display  14 . Display  14  may be a touch screen display that includes a touch sensor for gathering touch input from a user or display  14  may be insensitive to touch. A touch sensor for display  14  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. Display  14  may be a liquid crystal display, a light-emitting diode display (e.g., an organic light-emitting diode display), an electrophoretic display, or other display. 
     Input-output devices  12  may include optical components  18 . Optical components  18  may include light-emitting diodes and other light sources. As an example, optical components  18  may include one or more visible light-emitting diodes such as light-emitting diode  20 . Light-emitting diode  20  may provide constant illumination (e.g., to implement a flashlight function for device  10 ) and/or may emit pulses of flash illumination for a visible light camera such as visible light image sensor  26 . Optical components  18  may also include an infrared light source (e.g., a laser, lamp, light-emitting diode, etc.) such as infrared light-emitting diode  22 . Infrared light-emitting diode  22  may provide constant and/or pulsed illumination at an infrared wavelength such as 940 nm, a wavelength in the range of 800-1100 nm, etc. For example, infrared-light-emitting diode  22  may provide constant illumination for an infrared camera such as infrared image sensor  28 . Infrared image sensor  28  may, as an example, be configured to capture iris scan information from the eyes of a user and/or may be used to capture images for a facial recognition process implemented on control circuitry  16 . 
     Optical components  18  may also include optical proximity detector  24  and ambient light sensor  30 . 
     Optical proximity detector  24  may include an infrared light source such as an infrared light-emitting diode and a corresponding light detector such as an infrared photodetector for detecting when an external object that is illuminated by infrared light from the light-emitting diode is in the vicinity of device  10 . 
     Ambient light sensor  30  may be a monochrome ambient light sensor that measures the intensity of ambient light or may be a color ambient light sensor that measures ambient light color and intensity by making light measurements with multiple photodetectors each of which is provided with a corresponding color filter (e.g., a corresponding bandpass filter that passes red light, blue light, yellow light, green light, or light of other colors) and each of which therefore responds to ambient light in a different wavelength band. 
     In addition to optical components  18 , input-output devices  12  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, light-emitting diodes and other status indicators, non-optical sensors (e.g., temperature sensors, microphones, capacitive touch sensors, force sensors, gas sensors, pressure sensors, sensors that monitor device orientation and motion such as inertial measurement units formed from accelerometers, compasses, and/or gyroscopes), data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  12  and may receive status information and other output from device  10  using the output resources of input-output devices  12 . 
     Device  10  may have a housing. The housing may form a laptop computer enclosure, an enclosure for a wristwatch, a cellular telephone enclosure, a tablet computer enclosure, or other suitable device enclosure. A perspective view of a portion of an illustrative electronic device is shown in  FIG. 2 . In the example of  FIG. 2 , device  10  includes a display such as display  14  mounted in housing  32 . Housing  32 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  32  may be formed using a unibody configuration in which some or all of housing  32  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). Housing  32  may have any suitable shape. In the example of  FIG. 2 , housing  32  has a rectangular outline (footprint when viewed from above) and has four peripheral edges (e.g., opposing upper and lower edges and opposing left and right edges). Sidewalls may run along the periphery of housing  32 . 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, sapphire, or other clear layer (e.g., a transparent planar member that forms some or all of a front face of device  10  or that is mounted in other portions of device  10 ). Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button, a speaker port such as speaker port  34 , or other components. Openings may be formed in housing  32  to form communications ports (e.g., an audio jack port, a digital data port, etc.), to form openings for buttons, etc. In some configurations, housing  32  may have a rear housing wall formed from a planar glass member or other transparent layer (e.g., a planar member formed on a rear face of device  10  opposing a front face of device  10  that includes a display cover layer). 
     Display  14  may have an array of pixels  38  in active area AA (e.g., liquid crystal display pixels, organic light-emitting diode pixels, electrophoretic display pixels, etc.). Pixels  38  of active area AA may display images for a user of device  10 . Active area AA may be rectangular, may have notches along one or more of its edges, may be circular, may be oval, may be rectangular with rounded corners, and/or may have other suitable shapes. 
     Inactive portions of display  14  such as inactive border area IA may be formed along one or more edges of active area AA. Inactive border area IA may overlap circuits, signal lines, and other structures that do not emit light for forming images. To hide inactive circuitry and other components in border area IA from view by a user of device  10 , the underside of the outermost layer of display  14  (e.g., the display cover layer or other display layer) may be coated with an opaque masking material such as a layer of black ink (e.g., polymer containing black dye and/or black pigment, opaque materials of other colors, etc.) and/or other layers (e.g., metal, dielectric, semiconductor, etc.). Opaque masking materials such as these may also be formed on an inner surface of a planar rear housing wall formed from glass, ceramic, polymer, crystalline transparent materials such as sapphire, or other transparent material. 
     In the example of  FIG. 2 , speaker port  34  is formed from an elongated opening (e.g., a strip-shaped opening) that extends along a dimension parallel to the upper peripheral edge of housing  32 . A speaker may be mounted within device housing  32  in alignment with the opening for speaker port  34 . During operation of device  10 , speaker port  34  serves as an ear speaker port for a user of device  10  (e.g., a user may place opening  34  adjacent to the user&#39;s ear during telephone calls). 
     Optical components  18  (e.g., a visible digital image sensor, an infrared digital image sensor, a light-based proximity sensor, an ambient light sensor, visible and/or infrared light-emitting diodes that provide constant and/or pulsed illumination, etc.) may be mounted under one or more optical component windows such as optical component windows  40 . In the example of  FIG. 2 , four of windows  40  have circular outlines (e.g., circular footprints when viewed from above) and one of windows  40  has an elongated strip-shaped opening (e.g., an elongated strip-shaped footprint when viewed from above). The elongated window  40  is mounted between the sidewall along the upper peripheral edge of device  10  and speaker port  34  and extends parallel to the upper peripheral edge of housing  32 . If desired, windows such as optical windows  40  may have shapes other than circular and rectangular shapes. The examples of  FIG. 2  are merely illustrative. 
     Optical component windows such as windows  40  may be formed in inactive area IA of display  14  (e.g., an inactive border area in a display cover layer such as an inactive display region extending along the upper peripheral edge of housing  32 ) or may be formed in other portions of device  10  such as portions of a rear housing wall formed from a transparent member coated with opaque masking material, portions of a metal housing wall, polymer wall structures, etc. In the example of  FIG. 2 , windows  40  are formed adjacent to the upper peripheral edge of housing  32  between speaker port opening  34  in the display cover layer for display  14  and the sidewall along the upper edge of housing  32 . In some configurations, an opaque masking layer is formed on the underside of the display cover layer in inactive area IA and optical windows  40  are formed from openings within the opaque masking layer. To help optical windows  40  visually blend with the opaque masking layer, a dark ink layer, a metal layer, a thin-film interference filter formed from a stack of dielectric layers, and/or other structures may be overlap windows  40 . 
     In some modes of operation, device  10  may emit infrared light that has the potential to interfere with ambient light sensor operation. Consider, as an example, a scenario in which control circuitry  16  of device  10  is using infrared image sensor  28  to capture eye scan information and/or facial images (e.g., images of a user&#39;s face for use in performing face recognition operations to authenticate the user of device  10 ). As shown in  FIG. 3 , to ensure that the eyes and/or face of a user are sufficiently illuminated, device  10  may use infrared light source  22  (e.g., an infrared light-emitting diode, an infrared laser, etc.) to produce infrared light  48 . Light  48  may illuminate external objects in the vicinity of device  10  such as external object  44  (e.g., a user&#39;s face and/or eyes). Reflected infrared light  50  from external object  44  may be received and imaged using infrared digital image sensor  28  to produce infrared images of the face and/or eyes. 
     While reflected infrared light  50  is being imaged, stray infrared light reflected from object  44  such as stray infrared light  52  may be present at ambient light sensor  30 . To ensure that stray infrared light  52  does not interfere with the ambient light measurements being made with ambient light sensor  30 , ambient light sensor  30  may have an infrared blocking filter such as filter  60 . Filter  60  may be formed from materials that are transparent to visible light and that block infrared light such as blue glass (e.g., blue borosilicate glass or other infrared-light-blocking glass) and/or from thin-film interference filters formed from stacks of dielectric layers configured to block infrared light (e.g., infrared light at the wavelengths associated with stray light  52  and, if desired, additional infrared wavelengths) while passing visible light. 
     Ambient light  54  may be present in the surroundings of device  10  and may include light emitted from a light source such as light source  46  (e.g., the sun, a lamp, etc.). In some situations, ambient light  54  may be directional (e.g., the rays of light  54  from light source  46  may be aligned in a particular direction due to the nature of light source  46 ). To ensure that the response of ambient light detector  30  is even over a range of different orientations relative to light source  46  and ambient light  54 , a light diffuser such as diffuser  62  may be incorporated into ambient light sensor  30 . Ambient light sensor  30  may have one or more photodetectors (e.g., photodiodes) and associated amplifier and digitizing circuitry implemented on light detector integrated circuit  58 . Diffuser  62  may overlap visible-light-transmitting-and-infrared-light-blocking filter layer  60  and integrated circuit  58 . Diffuser  62  may be formed from polymer, glass, or other suitable materials. 
       FIG. 4  is a cross-sectional side view of ambient light sensor  30  in an illustrative electronic device  10 . As shown in  FIG. 4 , light detector integrated circuit  58  for ambient light sensor  30  may be mounted in alignment with optical component window  40  under display cover layer  78 . Display cover layer  78  may be formed from glass, polymer, ceramic, sapphire, and/or other transparent materials. In active area AA, display cover layer  78  may overlap pixels  38 , as shown in  FIG. 2 . In inactive areas of display  14  such as inactive area IA of  FIG. 4 , display cover layer  78  and optical component window  40  in layer  78  may overlap ambient light sensor  30 . 
     Ambient light sensor  30  may include light detector integrated circuit  58 . Light detector integrated circuit  58  may have one or more photodetectors  106  for making ambient light measurements (e.g., intensity measurements and color measurements). The photodetectors may be associated with different color sensitivities (e.g., a red channel, a blue channel, a green channel, a clear (non-colored) channel, etc.). 
     Light detector integrated circuit  58  may be supported using support structure  86 . Structures RG may be present between the portion of display cover layer  78  that is contacted by user&#39;s finger  80  and light detector integrated circuit  58 . Structures RG may include light diffusers, light collimators, visible-light-transmitting-and-infrared-light-blocking filters, light guides, lenses, and/or other optical components. These structures may be formed from glass, polymer, ceramic, sapphire and other crystalline materials, and/or other transparent dielectric structures. 
       FIG. 5  is a circuit diagram of an illustrative ambient light sensor. As shown in  FIG. 5 , ambient light sensor  30  may include integrating analog-to-digital converter  30 AD for converting analog output signals from photodetectors  106  into digital signals for control circuitry  16 . The signals produced by photodetectors  106  on their outputs (see, e.g., node N) are provided to corresponding inputs of integrating analog-to-digital converter  30 AD. During operation, the sensor output signals can be perturbed when a user&#39;s finger  80  or other external object contacts display cover layer  78  in the vicinity of ambient light sensor  30 . When, for example, a user&#39;s finger  80  overlaps or is adjacent to optical component window  40 , user&#39;s finger  80  may be capacitively coupled to light detector integrated circuit and photodetectors  106  via parasitic capacitance  82  ( FIG. 4 ). The user&#39;s finger may carry electrostatic charge. The presence of finger  80  can therefore perturb the signals on photodetectors  106 , which can lead to noise in the signals measured using ambient light sensor  30 . 
     To prevent noise from being generated when finger  80  is present, ambient light sensor  30  (and, if desired, other optical components  18 ) can be provided with electrostatic shielding. Shielding may be provided on support structures  86 , on light detector integrated circuit  58 , and/or other portions of ambient light sensor  30 . The shielding may be shorted to a fixed potential such as a ground potential, which helps block signal perturbations on node(s) N due to the presence of user&#39;s finger  80 . It may be desirable to use ground potential as the fixed potential for the shielding in some configurations as ground potential may be accessible with the system and may have less impact to the system than other fixed potentials. 
       FIG. 6  is a cross-sectional side view of an illustrative ambient light sensor of the type that may incorporate shielding. In the example of  FIG. 6 , ambient light sensor  30  is formed in alignment with optical component window  40  (sometimes referred to as an ambient light sensor window) in display  14 . Ambient light sensor  30  may be a color ambient light sensor having multiple channels each of which has a respective photodetector  106  configured to measure light in a different range of wavelengths (e.g., a different color). Using these photodetectors, ambient light sensors  30  can make color and intensity measurements on ambient light in the vicinity of device  10 . 
     Display  14  has an array of pixels  38  overlapped by display cover layer  78  in an active area (AA) of display  14 . In inactive area IA, portions of the underside of display cover layer  78  may be coated with a layer of opaque masking material  80  (e.g., black ink, etc.) to block internal components from view from the exterior of device  10 . Window  40  may be formed from an opening in the opaque masking material  80 . In window  40 , a thin layer of black ink  82  or other material that is at least partially transparent to visible light (e.g., a layer with a light transmission of at least 1%, at least 2%, at least 5%, 1-10%, less than 30%, etc.) may be present to help visually match the appearance of window  40  to the visual appearance of surrounding portions of display cover layer  78  (e.g., to match the appearance of opaque masking material  80 ) while still allowing ambient light sensor  30  to measure ambient light. 
     Color ambient light sensor  30  may include support structures such as support structure  86  (sometimes referred to as a sensor wall, a sensor body structure, a sensor housing structure, etc.). Clear adhesive such as a layer of pressure sensitive adhesive  84  may be used to couple support structure  86  to the underside of display cover layer  78  in alignment with optical component window  40 . Adhesive  84  may be transparent and may overlap optical window  40  and/or adhesive  84  may have a ring shape surrounding the periphery of window  40 . 
     Optional light guide  100  may be used to help guide light from optical window  40  at layer  78  to light detector integrated circuit  58 . Light guide  100  may include core  104  and cladding  102 . Core  104  and cladding  102  may be formed from transparent materials such as glass, polymer, sapphire or other crystalline material, etc. Core  104  may be formed from a material with a higher refractive index than cladding  102  to support light guiding in accordance with the principal of total internal reflection as light passes vertically through light guide  100 . 
     Optional optical layers  107  may be interposed between layer  82  and light guide  100 . Optional optical layers  126  may be interposed between light guide  100  and light detector integrated circuit  58 . Layers  107  and/or  126  may include light diffuser layers, light collimating layers, visible-light-transparent-and-infrared-light-blocking filter layers, and/or other optical films. As an example, layers  107  may include one or more light diffusers separated by air gaps and may include a light collimating layer. Layers  126  may include one or more visible-light-transmitting-and-infrared-blocking filters. Other configurations may be used for ambient light sensor  30 , if desired. The configuration of  FIG. 6  is merely illustrative. 
     As shown in  FIG. 6 , support structure  86  may form walls that surround layers  107  (e.g., light diffuser layers, etc.), that surround light guide  100 , and that surround layers  126  (e.g., visible-light-transmitting-and-infrared-light-blocking filter layer(s)). Viewed from above through layer  78 , support structure  86  may extend around the periphery of optical window  40 . Support structure  86  may be formed from an opaque material that blocks visible and infrared light such as black plastic and/or other opaque materials. 
     Support structure  86  may be used to form a one-piece or a multi-piece housing for sensor  30 . In the example of  FIG. 6 , support structure  86  has an upper portion  86 - 1  that houses components such as layers  107 , optional light guide  100 , and lower layers  126  and has a lower portion  86 - 2  (e.g., a printed circuit, a plastic substrate, etc.). Lower portion  86 - 2  may support and surround light detector integrated circuit  58 . 
     If desired, lower portion  86 - 2  may contain vias  114  and other metal traces (see, e.g., contacts  112 ). Light detector integrated circuit  58  can be mounted to the traces in portion  86 - 2  using wire bonds such as wire bond  140  or solder joints formed from solder  110 . Solder  110  may be used to couple contacts on light detector integrated circuit  58  such as solder pads  108  to corresponding contacts on portion  86 - 2  such as solder pads  112 . Metal traces such as vias  114  and other conductive signal paths in portion  86 - 2  may be used to couple contacts  112  to respective contacts (solder pads)  116  on the lower surface of portion  86 - 2 . Contacts  116  may, in turn, be soldered to contacts (solder pads)  120  on flexible printed circuit  96 . Flexible printed circuit  96  may be formed from metal traces  122  supported by dielectric printed circuit material  124  (e.g., polymer or other suitable dielectric). Metal traces  122  may include signal traces and one or more signal paths that short shielding to a fixed potential (e.g., ground traces that short shielding to a ground potential). 
     Electrostatic shield  92  may help prevent noise from finger  80  or other external objects from being coupled into photodetectors  106  of light detector integrated circuit  58 . Shield  92  may be formed from a metal coating (e.g., copper plated with gold and/or other metals) or other conductive layer on support structures  86 . As shown in  FIG. 6 , for example, shield  92  may be formed from metal on upper end of portion  86 - 1  (e.g., a metal layer on uppermost surface  86 ′ of portion  86 - 1 ). In this location, shield  92  may form a metal ring that runs around the periphery of window  40  (e.g., a shield layer that faces the inner surface of display cover layer  78 ). Adhesive layer  84  may be interposed between shield  92  and display cover layer  78 . 
     During operation, shield  92  can help shield ambient light sensor  30  from the influence of the user&#39;s finger or other external object adjacent to optical window  40 . A coupling capacitance between shield  92  and the user&#39;s finger is formed that is larger than the coupling capacitance between the user&#39;s finger and light detector integrated circuit  58  (which is farther from the user&#39;s finger). As a result, static charge on the user&#39;s finger will interact mostly with shield  92  and will not interact with photodetector  106  or significantly perturb the signal on node N. 
     Shield path  92 ′, which may be considered to form part of shield  92  and which may sometimes be referred to as a grounding path or shield signal path, may be formed from some of the same metal layer that is used in forming the portions of shield  92  at the upper surfaces of structure  86  and/or may be formed from other conductive material. Shield path  92 ′ may be shorted to a source of fixed potential such as ground  50  through a solder connection (solder joint  118 ) that is connected to a fixed potential (e.g., ground) formed from a trace at a fixed potential (e.g., a ground trace at ground) in metal traces  122  of printed circuit  96 . If desired, shielding such as shield  92  and path  92 ′ may cover all of the exterior sidewall surfaces of structures  86  and/or may be formed on other structures in ambient light sensor  30  (e.g., interior portions of structure  86 , metal embedded in the walls of support structure  86 , etc.). Shielding such as shield  92  may be formed from metal paint, metal deposited using physical vapor deposition, metal deposited using chemical vapor deposition, metal deposited using electroplating, and/or conductive material deposited using other techniques. If desired, shield  92  may include or be formed using a layer such as transparent conductive layer  92 ″ on the inner surface of display cover layer  78 . Layer  92 ″ may be, for example, a transparent conductive layer such as a layer of indium tin oxide. 
     In some configurations, electrostatic shielding may be provided using a transparent conductive layer that overlaps photodetectors  106 . Consider, as an example, the cross-sectional side view of illustrative light detector integrated circuit  58  that is shown in  FIG. 7 . As shown in  FIG. 7 , light detector integrated circuit  58  may include a semiconductor substrate such as substrate  132 . Substrate  132  may be formed from silicon or other semiconductor material. Photodetectors  106  may be formed from photodiodes in substrate  132 . As shown in  FIG. 7 , each photodetector  106  may include first terminal such as anode  142  and a second terminal such as cathode  144 . With one illustrative configuration, substrate  132  is a p-type substrate, cathode  144  is an n+ region, and anode  142  is a p+ region. Dielectric layers  134  (e.g., inorganic dielectric layers such as silicon oxide layers) and dielectric layer  152  (e.g., a silicon nitride layer) may be deposited on top of photodetectors  106 . A transparent conductive layer such as a layer of indium tin oxide or other transparent conductive material may overlap dielectric layer  152 , as shown by shielding layer (shield)  130 . The presence of shield  130  may help prevent perturbations to the signals produced by photodetector  106  during operation (e.g., noise from a user&#39;s finger or other source of static charge may be blocked). 
     Signal lines in light detector integrated circuit  58  may be formed from patterned metal traces in layers  134  such as vias  136  and metal pads  138 . As shown on the left-hand side of  FIG. 7 , for example, a contact pad for bonding wire  140  may be formed from a stack of metal pads  138 . Metal pads  138 , vias  136 , and other metal traces in dielectric layers  134  may also be used to form an electrical path that shorts anode  142  to shield layer  130  and to a fixed potential such as ground  50  ( FIG. 5 ) and may be used to form an electrical path that couples cathode  144  to the input of integrating analog-to-digital converter  30 AD ( FIG. 5 ). 
       FIG. 8  is a top view of light detector integrated circuit  58  showing how shield  130  may overlap and shield multiple photodetectors  106  on light detector integrated circuit. Each photodetector  106  may be overlapped by a respective color filter. Each color filter may be formed from colored ink or other material that selectively passes a desired range of wavelengths to an associated overlapped photodetector  106  (e.g., an organic color filter material such as polymer containing dyes and/or pigments). For example, a red-pass color filter may overlap a first photodetector  106  to form a red-light-sensing channel in ambient light sensor  30 , a blue-pass color filter may overlap a second photodetector  106  to form a blue-light-sensing channel in ambient light sensor  30 , etc. If desired, one or more of photodetectors  106  may have no overlapping color filter (e.g., these photodetectors may be associated with clear or “all color” channels). Stray infrared light may be blocked using a thin-film interference filter in layers  126 . The thin-film interference filter may be formed from a stack of dielectric layers (e.g., alternating higher and lower refractive index thin-film inorganic layers). An infrared blocking filter may be formed from any suitable number of dielectric layers (e.g., at least 5, at least 10, at least 20, 20-80, fewer than 100, etc.). Color filters and infrared blocking filters may be formed above and/or below shield  130 . 
     In addition to using shields such as shield  92  and/or shield  130 , electronic device  10  can use signal processing techniques to help reduce the likelihood of adjusting display brightness for display  14  or taking other action based on potentially noisy information from ambient light sensor  30 . 
     With a first illustrative arrangement, ambient light sensor readings from sensor  30  are averaged over time. A median filter or other filter may be used to discard or otherwise deemphasize or ignore ambient light sensor output spikes, thereby reducing the likelihood that a noisy signal will cause a fluctuation in display brightness. 
     With a second illustrative arrangement, an optical or capacitive proximity sensor (see, e.g., components  18 , photodetectors  106  in sensor  30 , etc.) or other sensor may be configured to detect the presence of user&#39;s finger  80  in the vicinity of optical window  40  (e.g., adjacent to ambient light sensor  30 ). When the user&#39;s finger or other object whose presence may perturb the output of the ambient light sensor is detected, corresponding ambient light sensor readings can be discarded. 
     With a third illustrative arrangement, control circuitry  16  can compare a clear (not-colored) channel in the photodetectors  106  of ambient light sensor  30  to a channel of a particular color (e.g., blue). The clear channel has an uncolored (clear) photodetector  106  and therefore receives visible light of all visible wavelengths with this photodetector. The channel of the particular color (blue in this example), receives only blue light. In normal usage, when finger  80  is not present, the output of the clear channel, which receives light for all colors, will be larger than the output for the blue channel. In response to static charge on a user&#39;s finger  80  that is capacitively coupled to ambient light sensor  30 , both the clear channel output and the blue channel output will be equally affected. Control circuitry  16  can use the ratio of the blue output to clear output to determine whether a given signal is noise or is a valid ambient light signal. If the ratio of clear to blue is high (e.g., above a predetermined threshold ratio of at least 1, at least 1.5, at least 2, at least 5, at least 25, etc.), the signal can be trusted as corresponding to an ambient light reading. If the ratio of clear to blue is low (e.g., at or below unity), noise is likely present and the reading can be discarded. Techniques such as these can be used in an electronic device that incorporates shield  92  and/or that incorporates shield  130 . 
     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: 20170922
Publication Date: 20191217
Grant Date: 20191217
Priority Date: 20170922
Inventors: GUO, DIANBO
ZHENG, DONG
Assignee: APPLE INC
CPC Classifications: [{"code": "H05B47/11", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05B47/11", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2330/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1688", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2330/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K9/0079", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/2007", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04107", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04107", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1684", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/2007", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0079", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05B37/0218", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0259", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10151", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2330/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/0259", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02B20/40", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 65808299