PATENT DOCUMENT

Publication Number: US-11594199-B2
Application Number: US-202217731755-A
Country: US
Kind Code: B2

Title: Electronic device with multiple ambient light sensors

Abstract:
An electronic device such as a cellular telephone or other device may have a housing with front and rear faces joined by a sidewall. A display may be mounted on the front face. The electronic device may include multiple ambient light sensors such as a front ambient light sensor on the front face and one or more supplemental ambient light sensors on the rear face and/or on the sidewall. The front ambient light sensor gathers a front ambient light intensity measurement and the supplemental ambient light sensor gathers a supplemental ambient light intensity measurement. During operation, control circuitry in the electronic device adjusts the display brightness based on data from the ambient light sensors. The control circuitry may implement power saving restrictions that limit when the supplemental ambient light intensity measurement is taken into account and/or that impose a brightness cap on the display brightness.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having opposing front and rear faces; 
 a display on the front face; 
 a front ambient light sensor on the front face that is configured to gather a front ambient light intensity measurement; 
 a rear ambient light sensor on the rear face that is configured to gather a rear ambient light intensity measurement; and 
 control circuitry configured to:
 compare the front and rear ambient light intensity measurements; 
 determine a ratio of the rear ambient light intensity measurement to the front ambient light intensity measurement and compare the ratio to a third threshold; 
 adjust a display brightness based on the front ambient light intensity measurement when the front ambient light intensity measurement is greater than the rear ambient light intensity measurement and greater than a first threshold; 
 adjust the display brightness based on the front ambient light intensity measurement when the ratio is less than the third threshold; and 
 adjust the display brightness based on the rear ambient light intensity measurement when the rear ambient light intensity measurement is greater than the front ambient light intensity measurement and greater than a second threshold, wherein the first and second thresholds are different. 
 
 
     
     
       2. The electronic device defined in  claim 1  wherein the control circuitry is configured to determine a brightness cap based on the front ambient light intensity measurement. 
     
     
       3. The electronic device defined in  claim 2  wherein the control circuitry is configured to compare the brightness cap to a brightness value that is based on the rear ambient light intensity measurement. 
     
     
       4. The electronic device defined in  claim 3  wherein the control circuitry is configured to set the display brightness to the brightness cap when the brightness value is greater than the brightness cap and when the rear ambient light intensity measurement is greater than the front ambient light intensity measurement and greater than the second threshold. 
     
     
       5. The electronic device defined in  claim 4  wherein the control circuitry is configured to set the display brightness to the brightness value when the brightness value is less than the brightness cap and when the rear ambient light intensity measurement is greater than the front ambient light intensity measurement and greater than the second threshold. 
     
     
       6. The electronic device defined in  claim 2  wherein the control circuitry is configured to determine a brightness value based on the front ambient light intensity measurement and wherein the brightness cap is equal to a multiple of the brightness value. 
     
     
       7. The electronic device defined in  claim 1  wherein the control circuitry is configured to adjust the display brightness based on the rear ambient light intensity measurement when the ratio is greater than the third threshold. 
     
     
       8. The electronic device defined in  claim 7  wherein the third threshold is greater than two. 
     
     
       9. The electronic device defined in  claim 1  further comprising a sensor configured to gather sensor data, wherein the control circuitry is configured to determine whether to use the front or rear ambient light intensity measurement based at least party on the sensor data, and wherein the sensor is selected from the group consisting of: a camera and a motion sensor. 
     
     
       10. An electronic device, comprising:
 a housing having opposing front and rear faces; 
 a display on the front face; 
 a first ambient light sensor on the housing that is configured to gather a first ambient light intensity measurement; 
 a second ambient light sensor on the housing that is configured to gather a second ambient light intensity measurement, wherein the first and second ambient light sensors face in different directions; and 
 control circuitry configured to:
 compare the first ambient light intensity measurement with a first threshold; 
 compare the second ambient light intensity measurement with a second threshold; 
 compare a ratio of the second ambient light intensity measurement to the first ambient light intensity measurement with a third threshold; and 
 adjust a display brightness based on whether the first ambient light intensity measurement is greater than the first threshold, the second ambient light intensity measurement is greater than the second threshold, and the ratio of the second ambient light intensity measurement to the first ambient light intensity measurement is greater than the third threshold. 
 
 
     
     
       11. The electronic device defined in  claim 10  wherein the first ambient light sensor is mounted on the front face of the housing. 
     
     
       12. The electronic device defined in  claim 11  wherein the second ambient light sensor is mounted on the rear face of the housing. 
     
     
       13. The electronic device defined in  claim 11  wherein the housing comprises a sidewall that joins the front and rear faces on an upper portion of the housing and wherein the second ambient light sensor is mounted on the sidewall of the housing. 
     
     
       14. The electronic device defined in  claim 10  further comprising a sensor configured to gather sensor data, wherein the control circuitry is configured to determine whether to use the first or second ambient light intensity measurement based at least party on the sensor data, and wherein the sensor is selected from the group consisting of: a camera and a motion sensor. 
     
     
       15. An electronic device, comprising:
 a housing having front and rear faces joined by a sidewall; 
 a display mounted on the front face; 
 a first ambient light sensor on the front face that is configured to gather a first ambient light intensity measurement; 
 a second ambient light sensor on the sidewall that is configured to gather a second ambient light intensity measurement; and 
 control circuitry configured to:
 compare a ratio of the second ambient light intensity measurement to the first ambient light intensity measurement with a threshold; 
 adjust a display brightness based on the first ambient light intensity measurement when the ratio of the second ambient light intensity measurement to the first ambient light intensity measurement is less than the threshold; and 
 adjust the display brightness based on the second ambient light intensity measurement when the ratio of the second ambient light intensity measurement to the first ambient light intensity measurement is greater than the threshold. 
 
 
     
     
       16. The electronic device defined in  claim 15  wherein the control circuitry is configured to:
 compare the first ambient light intensity measurement to a first threshold intensity; 
 compare the second ambient light intensity measurement to a second threshold intensity; and 
 adjust the display brightness based on whether the first ambient light intensity measurement is greater than the first threshold intensity and the second ambient light intensity measurement is greater than the second threshold intensity. 
 
     
     
       17. The electronic device defined in  claim 16  wherein the first threshold intensity is less than the second threshold intensity and wherein the threshold is greater than two.

Description:
This application claims the benefit of U.S. provisional patent application No. 63/182,467, filed Apr. 30, 2021, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     BACKGROUND 
     Electronic devices such as cellular telephones, tablet computers, and other equipment are sometimes provided with light sensors. For example, ambient light sensors may be incorporated into a device to provide the device with information on current lighting conditions. Ambient light readings may be used in controlling an electronic device. For example, the brightness of a display may be increased in bright ambient light conditions and decreased in dim ambient light conditions. 
     In conventional electronic devices, ambient light readings may not accurately represent the ambient light conditions perceived by a user, which can cause the display to appear too dim or too bright in certain situations. 
     SUMMARY 
     An electronic device such as a cellular telephone, tablet computer, or other device may have an electronic device housing with front and rear faces joined by a sidewall. The electronic device may include multiple ambient light sensors such as a front ambient light sensor on the front face and a supplemental ambient light sensor on the rear face, sidewall, or other surface of the electronic device. 
     A front ambient light sensor may gather a front ambient light intensity measurement, and a supplemental ambient light sensor may gather a supplemental ambient light intensity measurement. During operation, control circuitry in the electronic device may take action based on data from the ambient light sensors. For example, the brightness of a display may be adjusted and/or other display adjustments may be made. 
     The control circuitry may implement power saving restrictions that limit when the supplemental ambient light intensity measurement is taken into account and/or that impose a brightness cap on the display brightness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front perspective view of an illustrative electronic device having a display, a front ambient light sensor, and one or more supplemental ambient light sensors in accordance with an embodiment. 
         FIG.  2    is a rear perspective view of an illustrative electronic device of the type shown in  FIG.  1    having one or more supplemental ambient light sensors in accordance with an embodiment. 
         FIG.  3    is a schematic diagram of an illustrative electronic device with a front ambient light sensor and one or more supplemental ambient light sensors in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of an illustrative electronic device with a front ambient light sensor and one or more supplemental ambient light sensors in accordance with an embodiment. 
         FIGS.  5  and  6    are flow charts of illustrative steps involved in using ambient light sensor information from front and supplemental ambient light sensors to make display adjustments in accordance with embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may include one or more displays and one or more ambient light sensors. The ambient light sensors may be mounted on a front surface of the electronic device, a rear surface of the electronic device, a side surface of the electronic device (e.g., a top sidewall, a bottom sidewall, a left sidewall, a right sidewall, etc.). The ambient light sensors may gather ambient light intensity readings that may be used to adjust the brightness of a display in the electronic device. 
     If desired, one or more of the ambient light sensors in an electronic device may be color ambient light sensors that make measurements of light intensity in multiple color channels (e.g., multiple different overlapping visible light wavelength ranges) and that use this information in producing ambient light color information. The ambient light color information may be provided in the form of color coordinates in a desired color space, a color temperature, a correlated color temperature, a color spectrum, and/or other color data format. Configurations in which ambient light color measurements are made using color coordinates may sometimes be described herein as an example. 
       FIG.  1    is a perspective view of an illustrative electronic device having one or more ambient light sensors. As shown in  FIG.  1   , electronic device  10  may have a housing such as housing  12  that supports a display such as display  14 . Housing  12 , 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  12  may be formed using a unibody configuration in which some or all of housing  12  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.). If desired, housing  12  may form an enclosure for a cellular telephone or a tablet computer. Configurations in which housing  12  forms an enclosure for other types of electronic devices such laptop computers, desktop computers, wristwatch devices, and/or other devices may also be used. 
     Device  10  has opposing front and rear faces joined by sidewalls. In the illustrative configuration of  FIG.  1   , display  14  may be mounted on front face F of device  10 . A transparent portion of housing  12 , which may sometimes be referred to as a display cover layer, may cover display  14  on front face F. The display cover layer portion of housing  12  may be formed from a layer of transparent glass, clear plastic, sapphire, or other clear layer. 
     A rear perspective view of device  10  (e.g., device  10  of  FIG.  1   ) is shown in  FIG.  2   . As shown in  FIG.  2   , housing  12  may have portions that form a rear wall on rear face R of device  10  and portions that form sidewalls W (e.g., curved and/or planar sidewalls) for device  10 . 
     Ambient light sensors and other components may be mounted within housing  12 . With one illustrative configuration, which is sometimes described herein as an example, a first ambient light sensor such as front ambient light sensor  42  is mounted on front face F of housing  12 . One or more additional ambient light sensors such as supplemental ambient light sensor  44  may be mounted on one or more of sidewalls W (e.g., a top sidewall W on an upper portion of housing  12 , as shown in  FIG.  1   ) and/or may be mounted on rear face R of housing  12  (e.g., as shown in  FIG.  2   ). This is merely illustrative, however. If desired, supplemental ambient light sensor  44  may be mounted on sidewall W instead of or in addition to mounting supplemental ambient light sensor  44  on rear face R, or supplemental ambient light sensor  44  may be mounted on rear face R without any supplemental ambient light sensors  44  on sidewalls W. 
     In one illustrative configuration, device  10  includes a front ambient light sensor  42  on front face F of device  10  and a supplemental ambient light sensor  44  (sometimes referred to as a rear ambient light sensor) on rear face R of device  10 . The front and rear ambient light sensors face opposing (opposite) directions and gather ambient light measurements in opposing directions. Other arrangements in which device  10  has multiple ambient light sensors may be used, if desired. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma pixels, an array of organic light-emitting diode pixels or other light-emitting diodes, an array of electrowetting pixels, or pixels based on other display technologies. The array of pixels of display  14  forms an active area that displays images for a user of device  10 . The active area may be rectangular or may have other suitable shapes. The active area may cover all of front face F or an inactive border area may run along one or more edges of the active area and/or may form isolate island(s) within the active area. An ambient light sensor may be mounted in an area of front face F that is adjacent to the pixels of display  14  (e.g., outside of the active area of display  14 ) or that operates through a window within the pixels of display  14  (e.g., inside the active area of display  14 ). 
     During operation, control circuitry in device  10  may be used in processing ambient light measurements and taking appropriate action. For example, ambient light data (e.g., ambient light intensity and/or ambient light color) may be used in determining how to adjust display intensity and/or display color. Display color adjustments, which may sometimes be referred to as color cast adjustments or white point adjustments, may be made to adjust the color cast of images on display  14  (e.g., to make images appear warmer or cooler, more or less greenish, more or less blue, more or less yellow, etc.). The ambient light measurements that are obtained by the control circuitry in device  10  may be obtained from ambient light sensors mounted on front face F of device  10 , rear face R of device  10 , and/or one or more of sidewalls W of device  10 . 
     A schematic diagram of an illustrative electronic device  10  of the type that may be provided with one or more light sensors is shown in  FIG.  3   . 
     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.  3   , device  10  may include control circuitry  30 , communications circuitry  32 , and input-output devices  34 . 
     Control circuitry  30  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as 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  30  may be used to gather input from sensors and other input devices and may be used to control output devices. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communications circuits, power management units, audio chips, application specific integrated circuits, etc. 
     To support communications between device  10  and external electronic equipment, control circuitry  30  may communicate using communications circuitry  32 . Communications circuitry  32  may include antennas, radio-frequency transceiver circuitry, and other wireless communications circuitry and/or wired communications circuitry. Circuitry  32 , which may sometimes be referred to as control circuitry and/or control and communications circuitry, may, for example, support wireless communications using wireless local area network links, near-field communications links, cellular telephone links, millimeter wave links, and/or other wireless communications paths. 
     Input-output devices  34  may be used in gathering user input, in gathering information on the environment surrounding the user, and/or in providing a user with output. Input-output devices  34  in device  10  may include display  14  (e.g., a display mounted on front face F of housing  12 ). Display  14  has an array of pixels for displaying images to users. Display  14  may be a light-emitting diode display (e.g., an organic light-emitting diode or a display with a pixel array having light-emitting diodes formed from crystalline semiconductor dies), an electrophoretic display, a liquid crystal display, or other display. Display  14  may include a two-dimensional capacitive touch sensor or other touch sensor for gathering touch input or display  14  may be insensitive to touch. Haptic elements may be used to provide haptic feedback (e.g., haptic feedback in response to display touch sensor input, etc.). 
     Devices  34  may include sensors  36 . Sensors  36  may include force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors such as microphones, capacitive touch sensors, capacitive proximity sensors, non-capacitive touch sensors, ultrasonic sensors, sensors for detecting position, orientation, and/or motion (e.g., accelerometers, magnetic sensors such as compass sensors, gyroscopes, and/or inertial measurement units that contain some or all of these sensors), muscle activity sensors (EMG), heart rate sensors, electrocardiogram sensors, and other biometric sensors, radio-frequency sensors (e.g., radar and other ranging and positioning sensors), humidity sensors, moisture sensors, and/or other sensors. 
     Sensors  36  and other input-output devices  34  may include optical components such as light-emitting diodes (e.g., for camera flash or other blanket illumination, etc.), lasers such as vertical cavity surface emitting lasers and other laser diodes, laser components that emit multiple parallel laser beams (e.g., for three-dimensional sensing), lamps, and light sensing components such as photodetectors and digital image sensors. For example, sensors  36  in devices  34  may include optical sensors such as depth sensors (e.g., structured light sensors and/or depth sensors based on stereo imaging devices that can optically sense three-dimensional shapes), optical sensors such as self-mixing sensors and light detection and ranging (lidar) sensors that gather time-of-flight measurements and/or other measurements to determine distance between the sensor and an external object and/or that can determine relative velocity, proximity sensors based on light (e.g., optical proximity sensors that include light sources such as infrared light-emitting diodes and/or lasers and corresponding light detectors such as infrared photodetectors that can detect when external objects are within a predetermined distance), optical sensors such as visual odometry sensors that gather position and/or orientation information using images gathered with digital image sensors in cameras, gaze tracking sensors, visible light and/or infrared cameras having digital image sensors configured to gather image data, optical sensors for measuring ultraviolet light, and/or other optical sensor components (e.g., light sensitive devices and, if desired, light sources), photodetectors coupled to light guides, associated light emitters, and/or other optical components (one or more light-emitting devices, one or more light-detecting devices, etc.). 
     The optical sensors of sensors  36  may include color ambient light sensors that can measure ambient light levels. Each color sensor may have multiple photodetectors (e.g., photodiodes) covered with respective color filters corresponding to multiple respective color channels. The color filters may be configured to pass light of different colors (e.g., a red filter may pass red light for detection by a red photodiode in a red ambient light sensor channel, a blue filter may pass blue light for detection by a blue photodiode in a blue ambient light sensor channel, etc.). There may be, for example, 3-8 overlapping channels, at least 3 channels, at least 5 channels, fewer than 10 channels, or other suitable number of channels in each color ambient light sensor. 
     As shown in  FIG.  3   , the ambient light sensors of device  10  may include front color ambient light sensor  42 , which may sometimes be referred to as a front sensor or front light sensor, and one or more additional ambient light sensors such as supplemental ambient light sensor  44 , which may sometimes be referred to as a rear light sensor (e.g., in arrangements where sensor  44  is mounted to rear wall R of device  10 ) or a sidewall light sensor or side light sensor (e.g., in arrangements where sensor  44  is mounted on a sidewall W of device  10 ). The ambient light sensors in device  10  may face in different directions and/or may have different angles of view, thereby helping device  10  to satisfactorily sense the intensity and/or color of light in the user&#39;s environment. For example, sensors  42  and  44  may face in opposite directions and/or orthogonal directions, and/or two or more or three or more ambient light sensors in device  10  may otherwise face in different directions to allow light readings from different directions to be used in determining how to adjust the white point of display  14 . 
     One or more of ambient light sensors  42  and  44  may be color ambient light sensors. In some arrangements, only front ambient light sensor  42  may be color-sensitive while supplemental ambient light sensor  44  may be configured to measure light intensity without measuring light color. In other arrangements, both front light sensor  42  and supplemental light sensor  44  may be color-sensitive. Arrangements in which supplemental light sensor  44  is color-sensitive and front ambient light sensor  42  is not color-sensitive may also be used, if desired. 
     If desired, device  10  may include other components  40  such as audio components, power components, batteries, haptic devices, etc. 
     A cross-sectional side view of device  10  of  FIG.  3    is shown in  FIG.  4   . As shown in  FIG.  4   , portions of housing  12  may be formed on front face F and opposing rear face R. Sidewall portions of housing  12  such as sidewalls W may extend between front face F and rear face R. Display  14  has pixels that display an image viewable on front face F (e.g., an image viewable through optional overlapping transparent portions of housing  12  that form a display cover layer on front face F). Front sensor  42  is mounted on front face F of housing  12  or elsewhere in device  10  that allows front sensor  42  to face outwardly from front face F (e.g., in direction  54 , towards user  46 ). Front sensor  42  can therefore sense ambient light such as ambient light  52  from light source(s)  50  that are located in front of device  10 . 
     Supplemental sensor  44  may be mounted on rear face R of housing  12  (as shown in the example of  FIG.  4   ) or may otherwise be mounted on housing  12  to sense light in a different direction than front sensor  42 . For example, supplemental sensor  44  may face outwardly from rear face R (e.g., in direction  56 , away from rear face R and away from user  46 ). This allows rear sensor  44  to measure ambient light  60  from light source(s)  58  to the rear of device  10 . By gathering ambient light measurements in multiple directions, control circuitry  30  can make satisfactory dynamic adjustments to display  14  such as intensity adjustments, color adjustments (e.g., white point adjustments), and/or other adjustments to display  14  during operation of device  10 . For example, dynamic display brightness adjustments may be made to ensure that images are sufficiently bright for the user&#39;s lighting environment. Additionally, dynamic white point adjustments may be made to ensure that images that are presented on display  14  for user  46  are pleasing to the eye and are not too warm or too cold for the user&#39;s lighting environment. 
     As a user views display  14  on front face F, some ambient illumination in the user&#39;s environment may come from behind device  10 . For example, device  10  may be used indoors near a window. The window may allow bright cool daylight (e.g., from light source  58  such as the sun) into the user&#39;s viewing environment. As the user views images on display  14 , the user&#39;s eyes will adapt to the relatively bright cool daylight from the window. If the brightness and/or color cast of display  14  is not adjusted, the difference between the color and brightness of the ambient window light and the color cast and brightness of the image on display  14  may be unsettling to the user (e.g., the image on display  14  will appear too warm and/or may be insufficiently bright). To ensure that an image on display  14  is pleasing to the user in this scenario, control circuitry  30  may automatically adjust (e.g., increase) the brightness of display  14  based on the brightness of the ambient window light  60  from light source  58  and/or may automatically adjust the white point of display  14  to a colder value based on the color of ambient window light  60  from light source  58 . At night, when the window behind device  10  is dark, the user&#39;s viewing environment may be lit by indoor light sources (e.g., light source  50 ), such as a warm incandescent light source in front of display  14 . In these lighting conditions, the user&#39;s eyes will adapt to the dim and warm ambient light that is present, and control circuitry  30  may automatically adjust (e.g., reduce) the brightness of display  14  based on the brightness of the\light  52  from light source  50  and/or may automatically adjust the white point of display  14  to a warmer value based on the color of light  52  from light source  50  to ensure that images on display  14  are pleasing to the user. 
     The illustrative example of using device  10  indoors near a window is merely illustrative. Other scenarios in which the user&#39;s ambient lighting environment may be dominated by a light source behind device  10  include using device  10  in a vehicle, using device  10  outdoors (e.g., pointing a rear-facing camera in device  10  towards a bright outdoor scene such as a sunset), using device  10  in a dim indoor environment near a lamp that is behind device  10 , etc. Arrangements in which supplemental sensor  44  is on a top sidewall W of housing  12  (e.g., as shown in the example of  FIG.  1   ) may be beneficial for detecting a dominant light source in arrangements where device  10  is held more horizontal than vertical. For example, the user may view display  14  while holding device  10  horizontal to the ground (or otherwise not vertical to the ground). In this type of scenario, supplemental sensor  44  on top sidewall W can be used to measure ambient light brightness in the direction that is faced by top sidewall W. Control circuitry  30  may use this top sensor brightness value to adjust the brightness of display  14  when the measurements from sensor  44  and sensor  42  indicate that the user&#39;s ambient light viewing environment is dominated by a light source in the direction faced by top sidewall W. 
     Often user  46  will use display  14  in an ambient lighting environment that has a mixture of light sources. For example, warm and/or cold light with a first brightness may be present to the rear of device  10  and warm and/or cold light with a second brightness may be present to the front of device  10 . In these mixed lighting conditions, control circuitry  30  can perform weighting operations or other operations that allow color and/or brightness measurements from front sensors  42  and  44  to be combined, or control circuitry  30  may select a given one of the color and/or brightness measurements from sensors  42  and  44 . Control circuitry  30  may then adjust the brightness and/or color of display  14  based on the combined measurement or based on the selected measurement from a given one of sensors  42  and  44 . In other words, the color cast of display  14  may be adjusted based on an ambient light color measurement from front sensor  42 , may be adjusted based on an ambient light color measurement from supplemental sensor  44 , and/or may be adjusted based on a combined measurement resulting from weighting the front sensor data and supplemental sensor data. Similarly, the brightness of display  14  may be adjusted based on an ambient light brightness measurement from front sensor  42 , may be adjusted based on ambient light brightness measurement from supplemental sensor  44 , and/or may be adjusted based on a combined measurement resulting from weighting the front sensor data and supplemental data. 
     In many scenarios, a user&#39;s viewing environment may be dominated by the brightest light source in the environment. If desired, control circuitry  30  may obtain ambient light brightness readings from front sensor  42  and from supplemental sensor  44  and may compare the two readings to determine which measurement has a greater luminance value. Control circuitry  30  may automatically adjust the brightness of display  14  based on the greater of the two luminance values. If desired, control circuitry  30  may apply power saving constraints such as applying a brightness cap and/or only taking into account the supplemental sensor reading in certain scenarios (e.g., when the supplemental intensity measurement is sufficiently greater than the front intensity measurement, when the front and supplemental intensity measurements are greater than respective thresholds, when other input-output devices  34  such as motion sensors and/or cameras indicate device  10  is being used in a rear-lit scenario, etc.). 
     During use of device  10  by a user, the user tends to persistently view display  14  in direction  48 . As a result, the user&#39;s eyes can be more easily influenced by ambient light to the rear of device  10  than to the front of device  10 . 
     Consider, as an example, a first illustrative scenario in which front light  52  is brighter than rear light  60 . In this type of scenario, which may sometimes be referred to as a front-lit scenario, a front sensor luminance value may be used to determine the brightness of display  14 . For example, control circuitry  30  may input the sensor luminance reading from front sensor  42  (e.g., instead of the sensor luminance reading from supplemental sensor  44 ) into a function that maps sensor readings to display brightness values. 
     In a second illustrative scenario, rear light  60  is brighter than front light  52 . In this type of scenario, which may sometimes be referred to as a rear-lit scenario, the rear sensor luminance value measured using supplemental sensor  44  may be used to determine the brightness of display  14 . For example, control circuitry  30  may input the sensor luminance reading from supplemental sensor  44  (e.g., instead of the sensor luminance reading from front sensor  42 ) into a function that maps sensor readings to display brightness values. 
     A flow chart of illustrative operations involved in using ambient light readings from front sensor  42  and supplemental sensor  44  is shown in  FIG.  5   . During the operations of block  62 , control circuitry  30  may gather ambient light sensor readings from front ambient light sensor  42  and from supplemental ambient light sensor  44 . Each reading may include an ambient light luminance (light intensity) value (and, if desired, an ambient light color value). The front and rear intensities may be compared to determine whether the magnitude of the ambient light to the rear of device  10  (or upwards of device  10  in arrangements where sensor  44  is on an upper wall W of housing  12 , as shown in the example of  FIG.  1   ) is greater than or less than the magnitude of the ambient light to the front of device  10 . 
     If the light intensity reading of supplemental sensor  44  is greater than the light intensity reading of front sensor  42 , control circuitry  30  can conclude that device  10  is being operated in a rear-lit scenario (e.g., in which the dominant light source in the user&#39;s viewing environment is behind or otherwise not in front of device  10 ). In this type of scenario, the rear sensor luminance value measured using supplemental sensor  44  may be used to determine the brightness of display  14  (see, e.g., the operations of block  66 ). This may include, for example, inputting the sensor luminance reading from supplemental sensor  44  (e.g., instead of the sensor luminance reading from front sensor  42 ) into a function that maps sensor readings to display brightness values. 
     If the light intensity of front sensor  42  exceeds that of supplemental sensor  44 , control circuitry  30  can conclude that device  10  is being operated in a front-lit scenario (e.g., in which the dominant light source in the user&#39;s viewing environment is in front of device  10 ). In this type of scenario, the front sensor luminance value may be used to determine the brightness of display  14  (see, e.g., the operations of block  64 ). This may include, for example, inputting the sensor luminance reading from front sensor  42  (e.g., instead of the sensor luminance reading from supplemental sensor  44 ) into a function that maps sensor readings to display brightness values. 
     After determining the appropriate brightness value for display  14 , control circuitry  30  may adjust the brightness of display  14  accordingly during the operations of block  68 . If desired, control circuitry  30  may make other adjustments based on one or more of the sensor readings from sensors  42  and  44 , such as white point adjustments for display  14 , white point adjustments for cameras in device  10 , adjustments to camera flash color casts, and/or adjustments to other optical components in device  10 . 
     Because supplemental sensor  44  may face relatively bright light sources in many common scenarios, always adjusting the display brightness based on the bright ambient light measured by supplemental sensor  44  may result in excessive power consumption in device  10 . If desired, power saving restrictions may be implemented to ensure that the operation of display  14  does not consume excessive power during use of device  10 . For example, control circuitry  30  may impose restrictions that limit when the sensor reading from supplemental sensor  42  is taken into account for display brightness adjustments and/or may impose a brightness cap that limits the maximum brightness of display  14  in rear-lit scenarios. 
     A flow chart of illustrative operations involved in implementing illustrative power saving restrictions when using ambient light readings from front sensor  42  and supplemental sensor  44  is shown in  FIG.  6   . 
     During the operations of block  70 , control circuitry  30  may gather ambient light sensor readings from front ambient light sensor  42  and from supplemental ambient light sensor  44 . Each reading may include an ambient light luminance (light intensity) value (and, if desired, an ambient light color value). 
     During the operations of block  72 , control circuitry  30  may compare the front sensor luminance from front sensor  42  with a first threshold (e.g., a front threshold luminance value), may compare the supplemental sensor luminance from supplemental sensor  44  with a second threshold (e.g., a supplemental threshold luminance value), and may compare a ratio of the supplemental sensor luminance to the front sensor luminance with a third threshold (e.g., a non-zero value such as 2, 3, 4, 5, 6, greater than 1, greater than 2, greater than 6, less than 6, etc.). The first threshold (e.g., the front threshold luminance value) may be 50 lux, 80 lux, 100 lux, 200 lux, 500 lux, less than 500 lux, more than 500 lux, or any other suitable luminance value. The second threshold (e.g., the supplemental threshold luminance value) may be 500 lux, 800 lux, 1000 lux, 1200 lux, greater than 1200 lux, less than 1200 lux, or any other suitable luminance value. If desired, the supplemental threshold value may be greater than the front threshold luminance value. 
     If either the front sensor luminance or the supplemental sensor luminance is too low (e.g., below their respective thresholds) or if the ratio of the supplemental sensor luminance to the front sensor luminance is less than the third threshold (for example, if the supplemental sensor luminance is less than five times the front sensor luminance, less than three times the front sensor luminance, less than two times the front sensor luminance, etc.), then control circuitry  30  may determine the brightness for display  14  based on the front sensor luminance (e.g., during the operations of block  76 ). This may include, for example, inputting the sensor luminance reading from front sensor  42  (e.g., instead of the sensor luminance reading from supplemental sensor  44 ) into a function that maps sensor readings to display brightness values. 
     If both the front sensor luminance and the supplemental sensor luminance are sufficiently bright (e.g., greater than their respective thresholds) and if the ratio of the supplemental sensor luminance to the front sensor luminance is greater than the third threshold (for example, if the supplemental sensor luminance is at least five times the front sensor luminance, at least three times the front sensor luminance, at least two times the front sensor luminance, etc.), then processing may proceed to the operations of block  74 . 
     During the operations of block  74 , control circuitry  30  may determine what the brightness of the display  14  would be using the supplemental sensor luminance (e.g., by inputting the sensor luminance reading from supplemental sensor  44  into a function that maps sensor readings to display brightness values to obtain a supplemental-sensor-based brightness value). Control circuitry  30  may compare this supplemental-sensor-based brightness value with a brightness cap. The brightness cap may be a fixed value or may be based on the front sensor luminance from front sensor  42 . For example, the brightness cap may be some factor multiplied with what the display brightness would be if the display brightness were calculated based on the front sensor luminance from front sensor  42 . Control circuitry  30  may determine what the brightness for display  14  would be using the front sensor luminance by inputting the sensor luminance reading from front sensor  42  into a function that maps sensor readings to display brightness values to obtain a front-sensor-based brightness value. Control circuitry  30  may multiply this front-sensor-based brightness value by a factor (e.g., 1.5, 2, 2.5 3, 4, etc.) to obtain the brightness cap. If the supplemental-sensor-based brightness value (i.e., the display brightness calculated based on the supplemental sensor luminance) is greater than the brightness cap, then control circuitry  30  may set the display brightness to the brightness cap. If the supplemental-sensor-based brightness value is less than the brightness cap, then control circuitry  30  may set the display brightness to the supplemental-sensor-based brightness value. 
     After determining the appropriate brightness value for display  14 , control circuitry  30  may adjust the brightness of display  14  accordingly during the operations of block  78 . If desired, control circuitry  30  may make other adjustments based on one or more of the sensor readings from sensors  42  and  44 , such as white point adjustments for display  14 , white point adjustments for cameras in device  10 , adjustments to camera flash color casts, and/or adjustments to other optical components in device  10 . 
     The power saving restrictions discussed in connection with  FIG.  6    are merely illustrative. If desired, some of these restrictions may be implemented individually (e.g., the first and second thresholds may be imposed without imposing the third threshold, the third threshold may be imposed without imposing the first and second thresholds, the brightness cap may or may not be imposed, etc.). In some arrangements, different or additional restrictions may be applied to achieve power savings. For example, information from input-output devices  34  and/or communications circuitry  32  may be used to gather contextual information about the environment in which device  10  is being used, which in turn can be used to limit or allow when supplemental ambient light sensor data is taken into account. For example, control circuitry  30  may use input-output devices  34  (e.g., motion sensors, cameras, etc.) and/or communications circuitry  32  (e.g., global positioning system receiver circuitry, Bluetooth® communications circuitry, etc.) to determine when device  10  is being used in a car, when device  10  is being used to take a picture outdoors, when device  10  is being used indoors at night, etc. Based on this information, control circuitry  30  may determine when device  10  is likely operating in a rear-lit scenario and may limit use of supplemental ambient light sensor data to these scenarios to save power, if desired. 
     This is, however, merely illustrative. If desired, control circuitry  30  may not implement any power saving restrictions and/or may lift power saving restrictions in any suitable scenario. For example, if control circuitry  30  detects that device  10  is connected to a power source, control circuitry  30  may lift some or all power saving restrictions (e.g., by adjusting display brightness based on the brightest ambient light measurement regardless of whether the various threshold conditions discussed in connection with  FIG.  6    are met). 
     Device  10  may gather and use 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 by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20220428
Publication Date: 20230228
Grant Date: 20230228
Priority Date: 20210430
Inventors: YUNG, AMANDA K
JOHNSON, PAUL V
KUMAR, DANIEL P
WU, JIAYING
Assignee: APPLE INC
CPC Classifications: [{"code": "G09G5/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2360/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2360/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G5/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0626", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0626", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0626", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2360/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G5/10", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 83808656