PATENT DOCUMENT

Publication Number: US-11751462-B1
Application Number: US-202217842357-A
Country: US
Kind Code: B1

Title: Devices with displays having transparent openings and touch sensor metal

Abstract:
A display may have both a full pixel density region and a pixel removal region with a plurality of high-transmittance areas that overlap an optical sensor. Each high-transmittance area may be devoid of thin-film transistors and other display components. To improve transmission while maintaining satisfactory touch sensing performance, one or more segments of the touch sensor metal in the pixel removal region may have a reduced width relative to the touch sensor metal in the full pixel density region and/or one or more segments of the touch sensor metal in the pixel removal region may be omitted relative to the touch sensor metal in the full pixel density region. To mitigate a different appearance between the pixel removal region and the full pixel density region at off-axis viewing angles, the position of the touch sensor metal in the pixel removal region may be tuned.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 an input-output component; and 
 a display having an array of pixels, wherein the display has:
 a first portion that includes first touch sensor metal, wherein the first touch sensor metal includes a plurality of segments having a first width; and 
 a second portion that includes second touch sensor metal, wherein the second portion overlaps the input-output component, wherein the second touch sensor metal has a different arrangement than the first touch sensor metal, wherein the second touch sensor metal includes a second plurality of segments, wherein each segment of a first subset of the second plurality of segments has a second width that is less than the first width, and wherein each segment of a second subset of the second plurality of segments has the first width. 
 
 
     
     
       2. The electronic device defined in  claim 1 , wherein each segment of the second subset of the second plurality of segments is directly adjacent to a side of a pixel in the array of pixels. 
     
     
       3. The electronic device defined in  claim 2 , wherein each segment of the first subset of the second plurality of segments is not directly adjacent to a side of any pixel in the array of pixels. 
     
     
       4. The electronic device defined in  claim 1 , wherein the first touch sensor metal forms a first mesh that defines a first plurality of openings and wherein each one of the first plurality of openings overlaps a respective pixel in the array of pixels. 
     
     
       5. The electronic device defined in  claim 4 , wherein the second touch sensor metal forms a second mesh that defines a second plurality of openings, wherein each opening of a first subset of the second plurality of openings overlaps a respective pixel in the array of pixels, and wherein each opening of a second subset of the second plurality of openings does not overlap a respective pixel in the array of pixels. 
     
     
       6. The electronic device defined in  claim 1 , wherein the first touch sensor metal forms a first mesh that defines a first plurality of openings and wherein each one of the first plurality of openings overlaps a respective pixel in the array of pixels. 
     
     
       7. The electronic device defined in  claim 6 , wherein the second touch sensor metal has omitted segments relative to the first touch sensor metal. 
     
     
       8. The electronic device defined in  claim 6 , wherein the second touch sensor metal has portions that each form a mesh that defines a respective plurality of openings, wherein each opening in each respective plurality of openings overlaps a respective pixel in the array of pixels, and wherein the second touch sensor metal includes connecting segments that electrically connect adjacent portions. 
     
     
       9. The electronic device defined in  claim 8 , wherein the second touch sensor metal includes, for each row of pixels in the second portion, one connecting segment for each group of four pixels. 
     
     
       10. The electronic device defined in  claim 1 , wherein, in the first touch sensor metal, a first touch sensor metal segment is directly adjacent to a first side of a first pixel of a first color, wherein, in the second touch sensor metal, a second touch sensor metal segment is directly adjacent to a second side of a second pixel of the first color, wherein the first touch sensor metal segment is separated from the first side of the first pixel by a first distance, and wherein the second touch sensor metal segment is separated from the second side of the second pixel by a second distance that is different than the first distance. 
     
     
       11. The electronic device defined in  claim 1 , wherein the first touch sensor metal defines a first number of openings per unit area, wherein the second touch sensor metal defines a second number of openings per unit area, and wherein the second number of openings per unit area is less than the first number of openings per unit area. 
     
     
       12. The electronic device defined in  claim 1 , wherein the first touch sensor metal has a first total coverage per unit area and wherein the second touch sensor metal has a second total coverage per unit area that is lower than the first total coverage per unit area. 
     
     
       13. The electronic device defined in  claim 1 , wherein the first portion of the display has a first pixel density and wherein the second portion of the display has a second pixel density that is lower than the first pixel density. 
     
     
       14. The electronic device defined in  claim 1 , further comprising:
 a signal line having at least one non-planar portion that is adjacent to the array of pixels; and 
 a planar touch sensor metal patch that overlaps the signal line. 
 
     
     
       15. An electronic device, comprising:
 an input-output component; and 
 a display having an array of pixels, wherein the display has:
 a first portion that includes first touch sensor metal; and 
 a second portion that includes second touch sensor metal, wherein the second portion overlaps the input-output component, wherein, in the first touch sensor metal, a first touch sensor metal segment is directly adjacent to a first side of a first pixel of a first color, wherein, in the second touch sensor metal, a second touch sensor metal segment is directly adjacent to a second side of a second pixel of the first color, wherein the first touch sensor metal segment is separated from the first side of the first pixel by a first distance, and wherein the second touch sensor metal segment is separated from the second side of the second pixel by a second distance that is different than the first distance. 
 
 
     
     
       16. The electronic device defined in  claim 15 , wherein the first pixel has a third side that is orthogonal to the first side and that is longer than the first side, wherein the second pixel has a fourth side that is orthogonal to the second side and that is longer than the second side, and wherein the second distance is smaller than the first distance. 
     
     
       17. The electronic device defined in  claim 15 , wherein the first pixel has a third side that is orthogonal to the first side and that is shorter than the first side, wherein the second pixel has a fourth side that is orthogonal to the second side and that is shorter than the second side, and wherein the second distance is greater than the first distance. 
     
     
       18. The electronic device defined in  claim 15 , wherein, in the first touch sensor metal, a third touch sensor metal segment is directly adjacent to a third side of the first pixel, wherein, in the second touch sensor metal, a fourth touch sensor metal segment is directly adjacent to a fourth side of the second pixel, wherein the third touch sensor metal segment has a first width, and wherein the fourth touch sensor metal segment has a second width that is greater than the first width. 
     
     
       19. The electronic device defined in  claim 15 , wherein the second pixel has a third side that is orthogonal to the second side, wherein the second touch sensor metal has a third touch sensor metal segment that is directly adjacent to the third side, wherein the third touch sensor metal segment is separated from the third side of the second pixel by a third distance that is different than the second distance. 
     
     
       20. The electronic device defined in  claim 15 , wherein the second touch sensor metal segment is interposed between the second pixel and a third pixel, wherein the second touch sensor metal segment is separated from a third side of the third pixel by a third distance, and wherein the second distance is smaller than the third distance. 
     
     
       21. An electronic device comprising a display, wherein the display comprises:
 an array of pixels arranged in a first area; 
 a signal line in a second area that is adjacent to the first area; and 
 touch sensor metal having a first portion arranged in a repeating pattern over the first area and a second portion that forms a patch that overlaps the signal line in the second area. 
 
     
     
       22. The electronic device defined in  claim 21 , wherein the repeating pattern comprises a repeating grid of segments, wherein each segment has a first width, and wherein the patch has a second width that is at least five times greater than the first width. 
     
     
       23. The electronic device defined in  claim 21 , wherein the first area is an active area and wherein the second area is an inactive area. 
     
     
       24. The electronic device defined in  claim 21 , wherein the signal line has at least one non-planar portion and wherein the patch is a planar patch that overlaps the signal line. 
     
     
       25. The electronic device defined in  claim 21 , wherein the signal line has a first footprint and wherein the patch has a second footprint that matches the first footprint. 
     
     
       26. An electronic device, comprising:
 an input-output component; and 
 a display having an array of pixels, wherein the display has:
 a portion that overlaps the input-output component, wherein the portion includes touch sensor metal, wherein the touch sensor metal comprises:
 a first touch sensor metal segment that is directly adjacent to a first side of a pixel, wherein the first side has a first length, and wherein the first touch sensor metal segment has a first width; and 
 a second touch sensor metal segment that is directly adjacent to a second side of the pixel, wherein the second side is orthogonal to the first side, wherein the second side has a second length, wherein the first length is smaller than the second length, wherein the second touch sensor metal segment has a second width, and wherein the first width is greater than the second width.

Description:
This application claims the benefit of provisional patent application No. 63/315,432, filed Mar. 1, 2022, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     Electronic devices often include displays. For example, an electronic device may have an organic light-emitting diode (OLED) display based on organic light-emitting diode pixels. In this type of display, each pixel includes a light-emitting diode and thin-film transistors for controlling application of a signal to the light-emitting diode to produce light. The light-emitting diodes may include OLED layers positioned between an anode and a cathode. 
     There is a trend towards borderless electronic devices with a full-face display. These devices, however, may still need to include sensors such as cameras, ambient light sensors, and proximity sensors to provide other device capabilities. Since the display now covers the entire front face of the electronic device, the sensors will have to be placed under the display stack. In practice, however, the amount of light transmission through the display stack is very low (i.e., the transmission might be less than 20% in the visible spectrum), which severely limits the sensing performance under the display. 
     It is within this context that the embodiments herein arise. 
     SUMMARY 
     An electronic device may include a display and an optical sensor formed underneath the display. The display may have both a full pixel density region and a partial pixel density region or pixel removal region. The pixel removal region includes a plurality of high-transmittance areas that overlap the optical sensor. Each high-transmittance area may be devoid of thin-film transistors and other display components. The plurality of high-transmittance areas regions is configured to increase the transmittance of light through the display to the sensor. The high-transmittance areas may therefore be referred to as transparent windows in the display. 
     To increase transmittance in the pixel removal region, the arrangement of touch sensor metal in the pixel removal region may be different than the arrangement of touch sensor metal in the full pixel density region. In particular, the touch sensor metal in the pixel removal region may have a lower total coverage per unit area than in the full pixel density region. 
     To improve transmission while maintaining satisfactory touch sensing performance, one or more segments of the touch sensor metal in the pixel removal region may have a reduced width relative to the touch sensor metal in the full pixel density region and/or one or more segments of the touch sensor metal in the pixel removal region may be omitted relative to the touch sensor metal in the full pixel density region. 
     To mitigate a different appearance between the pixel removal region and the full pixel density region at off-axis viewing angles, the position of the touch sensor metal in the pixel removal region may be tuned. Some of the touch sensor metal segments in the pixel removal region may be shifted towards or away from their adjacent pixel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an illustrative electronic device having a display and one or more sensors in accordance with various embodiments. 
         FIG.  2    is a schematic diagram of an illustrative display with light-emitting elements in accordance with various embodiments. 
         FIG.  3    is a cross-sectional side view of an illustrative display stack that at least partially covers a sensor in accordance with various embodiments. 
         FIG.  4    is a cross-sectional side view of an illustrative display stack with a high-transmittance area that overlaps a sensor in accordance with various embodiments. 
         FIG.  5    is a top view of an illustrative display with transparent openings that overlap a sensor in accordance with various embodiments. 
         FIGS.  6 A- 6 F  are top views of illustrative displays showing possible positions for pixel removal regions in accordance with various embodiments. 
         FIG.  7    is a top view of an illustrative full pixel density region of a display that includes touch sensor metal in accordance with various embodiments. 
         FIG.  8    is a top view of an illustrative pixel removal region of a display that includes touch sensor metal in accordance with various embodiments. 
         FIG.  9    is a top view of an illustrative pixel removal region of a display that includes touch sensor metal with narrowed segments in accordance with various embodiments. 
         FIGS.  10 - 13    are top views of illustrative pixel removal regions that include touch sensor metal with omitted segments in accordance with various embodiments. 
         FIG.  14    is a diagram showing how a pixel removal process may result in green emissive sub-pixels of a single orientation being present in a layout for a pixel removal region in accordance with various embodiments. 
         FIG.  15    is a top view of an illustrative full pixel density region showing the spacing of touch sensor metal in accordance with various embodiments. 
         FIG.  16    is a top view of an illustrative pixel removal region showing how the spacing of touch sensor metal may be shifted to mitigate differences in off-axis color shift between the pixel removal region and the full pixel density region in accordance with various embodiments. 
         FIG.  17    is a top view of an illustrative pixel removal region with thick touch sensor metal segments to mitigate differences in off-axis color shift between the pixel removal region and the full pixel density region in accordance with various embodiments. 
         FIG.  18 A  is a top view of an illustrative display with a signal line adjacent to an array of pixels in accordance with various embodiments. 
         FIG.  18 B  is a cross-sectional side view of the illustrative display of  FIG.  18 A  in accordance with various embodiments. 
         FIG.  19 A  is a top view of an illustrative display with a planar touch sensor metal patch that overlaps a non-planar signal line in accordance with various embodiments. 
         FIG.  19 B  is a cross-sectional side view of the illustrative display of  FIG.  19 A  in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device of the type that may be provided with a display 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 display, a computer display that contains an embedded computer, 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, or other electronic equipment. Electronic device  10  may have the shape of a pair of eyeglasses (e.g., supporting frames), may form a housing having a helmet shape, or may have other configurations to help in mounting and securing the components of one or more displays on the head or near the eye of a user. 
     As shown in  FIG.  1   , electronic device  10  may include control circuitry  16  for supporting the operation of device  10 . Control circuitry  16  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. 
     Input-output circuitry in device  10  such as input-output devices  12  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  12  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input resources of input-output devices  12  and may receive status information and other output from device  10  using the output resources of input-output devices  12 . 
     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. A touch sensor for display  14  may be formed from electrodes formed on a common display substrate with the display pixels of display  14  or may be formed from a separate touch sensor panel that overlaps the pixels of display  14 . If desired, display  14  may be insensitive to touch (i.e., the touch sensor may be omitted). Display  14  in electronic device  10  may be a head-up display that can be viewed without requiring users to look away from a typical viewpoint or may be a head-mounted display that is incorporated into a device that is worn on a user&#39;s head. If desired, display  14  may also be a holographic display used to display holograms. 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images on display  14 . 
     Input-output devices  12  may also include one or more sensors  13  such as force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors such as microphones, touch and/or proximity sensors such as capacitive sensors (e.g., a two-dimensional capacitive touch sensor associated with a display and/or a touch sensor that forms a button, trackpad, or other input device not associated with a display), and other sensors. In accordance with some embodiments, sensors  13  may include optical sensors such as optical sensors that emit and detect light (e.g., optical proximity sensors such as transreflective optical proximity structures), ultrasonic sensors, and/or other touch and/or proximity sensors, monochromatic and color ambient light sensors, image sensors, fingerprint sensors, temperature sensors, proximity sensors and other sensors for measuring three-dimensional non-contact gestures (“air gestures”), pressure 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), health sensors, radio-frequency sensors, depth sensors (e.g., structured light sensors and/or depth sensors based on stereo imaging devices), optical sensors such as self-mixing sensors and light detection and ranging (lidar) sensors that gather time-of-flight measurements, humidity sensors, moisture sensors, gaze tracking sensors, and/or other sensors. In some arrangements, device  10  may use sensors  13  and/or other input-output devices to gather user input (e.g., buttons may be used to gather button press input, touch sensors overlapping displays can be used for gathering user touch screen input, touch pads may be used in gathering touch input, microphones may be used for gathering audio input, accelerometers may be used in monitoring when a finger contacts an input surface and may therefore be used to gather finger press input, etc.). 
     Display  14  may be an organic light-emitting diode display, an array of discrete light-emitting diodes (microLEDs) each formed from a crystalline semiconductor die, or may be a display based on other types of display technology (e.g., liquid crystal displays). Device configurations in which display  14  is an organic light-emitting diode display are sometimes described herein as an example. This is, however, merely illustrative. Any suitable type of display may be used, if desired. In general, display  14  may have a rectangular shape (i.e., display  14  may have a rectangular footprint and a rectangular peripheral edge that runs around the rectangular footprint) or may have other suitable shapes. Display  14  may be planar or may have a curved profile. 
     A top view of a portion of display  14  is shown in  FIG.  2   . As shown in  FIG.  2   , display  14  may have an array of pixels  22  formed on a substrate. Pixels  22  may receive data signals over signal paths such as data lines D and may receive one or more control signals over control signal paths such as horizontal control lines G (sometimes referred to as gate lines, scan lines, emission control lines, etc.). There may be any suitable number of rows and columns of pixels  22  in display  14  (e.g., tens or more, hundreds or more, or thousands or more). Each pixel  22  may include a light-emitting diode  26  that emits light  24  under the control of a pixel control circuit formed from thin-film transistor circuitry such as thin-film transistors  28  and thin-film capacitors. Thin-film transistors  28  may be polysilicon thin-film transistors, semiconducting-oxide thin-film transistors such as indium zinc gallium oxide (IGZO) transistors, or thin-film transistors formed from other semiconductors. Pixels  22  may contain light-emitting diodes of different colors (e.g., red, green, and blue) to provide display  14  with the ability to display color images or may be monochromatic pixels. 
     Display driver circuitry may be used to control the operation of pixels  22 . The display driver circuitry may be formed from integrated circuits, thin-film transistor circuits, or other suitable circuitry. Display driver circuitry  30  of  FIG.  2    may contain communications circuitry for communicating with system control circuitry such as control circuitry  16  of  FIG.  1    over path  32 . Path  32  may be formed from traces on a flexible printed circuit or other cable. During operation, the control circuitry (e.g., control circuitry  16  of  FIG.  1   ) may supply display driver circuitry  30  with information on images to be displayed on display  14 . 
     To display the images on display pixels  22 , display driver circuitry  30  may supply image data to data lines D while issuing clock signals and other control signals to supporting display driver circuitry such as gate driver circuitry  34  over path  38 . If desired, display driver circuitry  30  may also supply clock signals and other control signals to gate driver circuitry  34  on an opposing edge of display  14 . 
     Gate driver circuitry  34  (sometimes referred to as row control circuitry) may be implemented as part of an integrated circuit and/or may be implemented using thin-film transistor circuitry. Horizontal control lines G in display  14  may carry gate line signals such as scan line signals, emission enable control signals, and other horizontal control signals for controlling the display pixels  22  of each row. There may be any suitable number of horizontal control signals per row of pixels  22  (e.g., one or more row control signals, two or more row control signals, three or more row control signals, four or more row control signals, etc.). 
     The region on display  14  where the display pixels  22  are formed may sometimes be referred to herein as the active area. Electronic device  10  has an external housing with a peripheral edge. The region surrounding the active area and within the peripheral edge of device  10  is the border region. Images can only be displayed to a user of the device in the active region. It is generally desirable to minimize the border region of device  10 . For example, device  10  may be provided with a full-face display  14  that extends across the entire front face of the device. If desired, display  14  may also wrap around over the edge of the front face so that at least part of the lateral edges and/or at least part of the back surface of device  10  is used for display purposes. 
     Device  10  may include a sensor  13  mounted behind display  14  (e.g., behind the active area of the display).  FIG.  3    is a cross-sectional side view of an illustrative display stack of display  14  that at least partially covers a sensor in accordance with an embodiment. As shown in  FIG.  3   , the display stack may include a substrate such as substrate  300 . Substrate  300  may be formed from glass, metal, plastic, ceramic, sapphire, or other suitable substrate materials. In some arrangements, substrate  300  may be an organic substrate formed from polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) (as examples). One or more polyimide (PI) layers  302  may be formed over substrate  300 . The polyimide layers may sometimes be referred to as an organic substrate (e.g., substrate  300  is a first substrate layer and substrate  302  is a second substrate layer). The surface of substrate  302  may optionally be covered with one or more buffer layers  303  (e.g., inorganic buffer layers such as layers of silicon oxide, silicon nitride, amorphous silicon, etc.). 
     Thin-film transistor (TFT) layers  304  may be formed over inorganic buffer layers  303  and organic substrates  302  and  300 . The TFT layers  304  may include thin-film transistor circuitry such as thin-film transistors, thin-film capacitors, associated routing circuitry, and other thin-film structures formed within multiple metal routing layers and dielectric layers. Organic light-emitting diode (OLED) layers  306  may be formed over the TFT layers  304 . The OLED layers  306  may include a diode cathode layer, a diode anode layer, and emissive material interposed between the cathode and anode layers. The OLED layers may include a pixel definition layer that defines the light-emitting area of each pixel. The TFT circuitry in layer  304  may be used to control an array of display pixels formed by the OLED layers  306 . 
     Circuitry formed in the TFT layers  304  and the OLED layers  306  may be protected by encapsulation layers  308 . As an example, encapsulation layers  308  may include a first inorganic encapsulation layer, an organic encapsulation layer formed on the first inorganic encapsulation layer, and a second inorganic encapsulation layer formed on the organic encapsulation layer. Encapsulation layers  308  formed in this way can help prevent moisture and other potential contaminants from damaging the conductive circuitry that is covered by layers  308 . Substrate  300 , polyimide layers  302 , buffer layers  303 , TFT layers  304 , OLED layers  306 , and encapsulation layers  308  may be collectively referred to as a display panel. 
     One or more polarizer films  312  may be formed over the encapsulation layers  308  using adhesive  310 . Adhesive  310  may be implemented using optically clear adhesive (OCA) material that offer high light transmittance. One or more touch layers  316  that implement the touch sensor functions of touch-screen display  14  may be formed over polarizer films  312  using adhesive  314  (e.g., OCA material). For example, touch layers  316  may include horizontal touch sensor electrodes and vertical touch sensor electrodes collectively forming an array of capacitive touch sensor electrodes. Lastly, the display stack may be topped off with a cover glass layer  320  (sometimes referred to as a display cover layer  320 ) that is formed over the touch layers  316  using additional adhesive  318  (e.g., OCA material). display cover layer  320  may be a transparent layer (e.g., transparent plastic or glass) that serves as an outer protective layer for display  14 . The outer surface of display cover layer  320  may form an exterior surface of the display and the electronic device that includes the display. 
     Still referring to  FIG.  3   , sensor  13  may be formed under the display stack within the electronic device  10 . As described above in connection with  FIG.  1   , sensor  13  may be an optical sensor such as a camera, proximity sensor, ambient light sensor, fingerprint sensor, or other light-based sensor. In some cases, sensor  13  may include a light-emitting component that emits light through the display. Sensor  13  may therefore sometimes be referred to as input-output component  13 . Input-output component  13  may be a sensor or a light-emitting component (e.g., that is part of a sensor). The performance of input-output component  13  depends on the transmission of light traversing through the display stack, as indicated by arrow  350 . A typical display stack, however, has fairly limited transmission properties. For instance, more than 80% of light in the visible and infrared light spectrum might be lost when traveling through the display stack, which makes sensing under display  14  challenging. 
     Each of the multitude of layers in the display stack contributes to the degraded light transmission to sensor  13 . In particular, the dense thin-film transistors and associated routing structures in TFT layers  304  of the display stack contribute substantially to the low transmission. In accordance with an embodiment, at least some of the display pixels may be selectively removed in regions of the display stack located directly over sensor(s)  13 . Regions of display  14  that at least partially cover or overlap with sensor(s)  13  in which at least a portion of the display pixels have been removed are sometimes referred to as pixel removal regions, low density pixel regions, or high transmittance regions. Removing and/or shrinking display pixels (e.g., removing transistors and/or capacitors associated with one or more sub-pixels) in the pixel removal regions can drastically help increase transmission and improve the performance of the under-display sensor  13 . In addition to removing display pixels, portions of additional layers such as polyimide layers  302  and/or substrate  300  may be removed for additional transmission improvement. Polarizer  312  may also be bleached for additional transmission improvement. 
       FIG.  4    is a cross-sectional side view of an illustrative display showing how pixels may be removed in a pixel removal region  332  to increase transmission through the display. As shown in  FIG.  4   , display  14  may include a pixel region  322  and a high-transmittance area  324 . In the pixel region  322 , the display may include a pixel formed from emissive material  306 - 2  that is interposed between an anode  306 - 1  and a cathode  306 - 3 . Signals may be selectively applied to anode  306 - 1  to cause emissive material  306 - 2  to emit light for the pixel. Circuitry in thin-film transistor layer  304  may be used to control the signals applied to anode  306 - 1 . 
     In high-transmittance area  324 , anode  306 - 1  and emissive material  306 - 2  may be omitted. Without the high-transmittance area, an additional pixel may be formed in area  324  adjacent to the pixel in area  322 . However, to increase the transmittance of light to sensor  13  under the display, the pixels in area  324  are removed. The absence of emissive material  306 - 2  and anode  306 - 1  may increase the transmittance through the display stack. Additional circuitry within thin-film transistor layer  304  may also be omitted in high-transmittance area  324  to increase transmittance. 
     Additional transmission improvements through the display stack may be obtained by selectively removing additional components from the display stack in high-transmittance area  324 . As shown in  FIG.  4   , a portion of cathode  306 - 3  may be removed in high-transmittance area  324 . This results in an opening  326  in the cathode  306 - 3 . Said another way, the cathode  306 - 3  may have conductive material that defines an opening  326  in the pixel removal region. Removing the cathode in this way allows for more light to pass through the display stack to sensor  13 . Cathode  306 - 3  may be formed from any desired conductive material. The cathode may be removed via etching (e.g., laser etching or plasma etching). Alternatively, the cathode may be patterned to have an opening in high-transmittance area  324  during the original cathode deposition and formation steps. 
     Polyimide layers  302  may be removed in high-transmittance area  324  in addition to cathode layer  306 - 3 . The removal of the polyimide layers  302  results in an opening  328  in the pixel removal region. Said another way, the polyimide layer may have polyimide material that defines an opening  328  in the high-transmittance region. The polyimide layers may be removed via etching (e.g., laser etching or plasma etching). Alternatively, the polyimide layers may be patterned to have an opening in high-transmittance area  324  during the original polyimide formation steps. Removing the polyimide layer  302  in high-transmittance area  324  may result in additional transmittance of light to sensor  13  in high-transmittance area  324 . 
     Substrate  300  may be removed in high-transmittance area  324  in addition to cathode layer  306 - 3  and polyimide layer  302 . The removal of the substrate  300  results in an opening  330  in the high-transmittance area. Said another way, the substrate  300  may have material (e.g., PET, PEN, etc.) that defines an opening  330  in the pixel removal region. The substrate may be removed via etching (e.g., with a laser). Alternatively, the substrate may be patterned to have an opening in high-transmittance area  324  during the original substrate formation steps. Removing the substrate  300  in high-transmittance area  324  may result in additional transmittance of light in high-transmittance area  324 . The polyimide opening  328  and substrate opening  330  may be considered to form a single unitary opening. When removing portions of polyimide layer  302  and/or substrate  300 , inorganic buffer layers  303  may serve as an etch stop for the etching step. Openings  328  and  330  may be filled with air or another desired transparent filler. 
     In addition to having openings in cathode  306 - 3 , polyimide layers  302 , and/or substrate  300 , the polarizer  312  in the display may be bleached for additional transmittance in the pixel removal region. 
       FIG.  5    is a top view of an illustrative display showing how high-transmittance areas may be incorporated into a pixel removal region  332  of the display. As shown, the display may include a plurality of pixels. In  FIG.  5   , there are a plurality of red pixels (R), a plurality of blue pixels (B), and a plurality of green pixels (G). The red, blue, and green pixels may be arranged in any desired pattern. Different nomenclature may be used to refer to the red, green, and blue pixels in the display. As one option, the red, blue, and green pixels may be referred to simply as pixels. As another option, the red, blue, and green pixels may instead be referred to as red, blue, and green sub-pixels (or emissive sub-pixels). In this example, a group of sub-pixels of different colors may be referred to as pixel. In high-transmittance areas  324 , no sub-pixels are included in the display (even though sub-pixels would normally be present if the normal sub-pixel pattern was followed). 
     To provide a uniform distribution of sub-pixels across the display surface, an intelligent pixel removal process may be implemented that systematically eliminates the closest sub-pixel of the same color (e.g., the nearest neighbor of the same color may be removed). The pixel removal process may involve, for each color, selecting a given sub-pixel, identifying the closest or nearest neighboring sub-pixels of the same color (in terms of distance from the selected sub-pixel), and then eliminating/omitting those identified sub-pixels in the final pixel removal region. With this type of arrangement, there may be high-transmittance areas in the pixel removal region, allowing a sensor or light-emitting component to operate through the display in the pixel removal region. Additionally, because some of the pixels remain present in the pixel removal region (e.g., 50% of the pixels in the layout of  FIG.  5   ), the pixel removal region may not have a perceptibly different appearance from the rest of the display for a viewer. 
     As shown in  FIG.  5   , display  14  may include high-transmittance areas  324 . Each high-transmittance area  324  may have pixels removed in that area. Each high-transmittance area also has an increased transparency compared to pixel region  322 . The high-transmittance areas  324  may sometimes be referred to as transparent windows  324 , transparent display windows  324 , transparent openings  324 , transparent display openings  324 , etc. The transparent display windows may allow for light to be transmitted through the display to an underlying sensor or for light to be transmitted through the display from a light source underneath the display. The transparency of transparent openings  324  (for visible and/or infrared light) may be greater than 25%, greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 80%, greater than 90%, etc. The transparency of transparent openings  324  may be greater than the transparency of pixel region  322 . The transparency of pixel region  322  may be less than 25%, less than 20%, less than 10%, less than 5%, etc. The pixel region  322  may sometimes be referred to as opaque display region  322 , opaque region  322 , opaque footprint  322 , etc. Opaque region  322  includes light emitting pixels R, G, and B, and blocks light from passing through the display. 
     The pattern of pixels ( 322 ) and high-transmittance areas ( 324 ) in  FIG.  5    is merely illustrative. The pattern of sub-pixels and pixel removal regions in  FIG.  5    is also merely illustrative. In  FIG.  5   , the display edge may be parallel to the X axis or the Y axis. The front face of the display may be parallel to the XY plane such that a user of the device views the front face of the display in the Z direction. In  FIG.  5   , every other sub-pixel may be removed for each color. The resulting pixel configuration has 50% of the sub-pixels removed. In  FIG.  5   , the remaining pixels follow a zigzag pattern across the display (with two green sub-pixels for every one red or blue sub-pixel). In  FIG.  5   , the sub-pixels have edges angled relative to the edges of the display (e.g., the edges of the sub-pixels are at non-zero, non-orthogonal angles relative to the X-axis and Y-axis). This example is merely illustrative. If desired, each individual sub-pixel may have edges parallel to the display edge, a different proportion of pixels may be removed for different colors, the remaining pixels may follow a different pattern, etc. 
     In general, the display sub-pixels may be partially removed from any region(s) of display  14 .  FIGS.  6 A- 6 F  are front views showing how display  14  may have one or more localized pixel removal regions in which the sub-pixels are selectively removed. The example of  FIG.  6 A  illustrates various local pixel removal regions  332  (sometimes referred to as low pixel density regions or high-transmittance region  332 ) physically separated from one another (i.e., the various pixel removal regions  332  are non-continuous) by full pixel density region  334 . The full pixel density region  334  (sometimes referred to as full pixel density area  334 ) does not include any transparent windows  324  (e.g., none of the sub-pixels are removed and the display follows the pixel pattern without modifications). The full pixel density region  334  has a higher pixel density (pixels per unit area) than low pixel density regions  332 . The three pixel removal regions  332 - 1 ,  332 - 2 , and  332 - 3  in  FIG.  6 A  might for example correspond to three different sensors formed underneath display  14  (with one sensor per pixel removal region). 
     The example of  FIG.  6 B  illustrates a continuous pixel removal region  332  formed along the top border of display  14 , which might be suitable when there are many optical sensors positioned near the top edge of device  10 . The example of  FIG.  6 C  illustrates a pixel removal region  332  formed at a corner of display  14  (e.g., a rounded corner area of the display). In some arrangements, the corner of display  14  in which pixel removal region  332  is located may be a rounded corner (as in  FIG.  6 C ) or a corner having a substantially 90° corner. The example of  FIG.  6 D  illustrates a pixel removal region  332  formed only in the center portion along the top edge of device  10  (i.e., the pixel removal region covers a recessed notch area in the display).  FIG.  6 E  illustrates another example in which pixel removal regions  332  can have different shapes and sizes.  FIG.  6 F  illustrates yet another suitable example in which the pixel removal region covers the entire display surface. These examples are merely illustrative and are not intended to limit the scope of the present embodiments. If desired, any one or more portions of the display overlapping with optically based sensors or other sub-display electrical components may be designated as a pixel removal region/area. 
       FIG.  5    shows an example of a pixel removal region where some sub-pixels are removed in favor of transparent openings in the display.  FIG.  5    shows a layout for sub-pixels within the pixel removal region. It should be noted that these layouts are for the emissive layer of each sub-pixel. 
     Each display pixel  22  may include both a thin-film transistor layer and an emissive layer. Each emissive layer portion may have associated circuitry on the thin-film transistor layer that controls the magnitude of light emitted from that emissive layer portion. Both the emissive layer and thin-film transistor layer may have corresponding sub-pixels within the pixel. Each sub-pixel may be associated with a different color of light (e.g., red, green, and blue). The emissive layer portion for a given sub-pixel does not necessarily need to have the same footprint as its associated thin-film transistor layer portion. Hereinafter, the term sub-pixel may sometimes be used to refer to the combination of an emissive layer portion and a thin-film transistor layer portion. Additionally, the thin-film transistor layer may be referred to as having thin-film transistor sub-pixels (e.g., a portion of the thin-film transistor layer that controls a respective emissive area, sometimes referred to as thin-film transistor layer pixels, thin-film transistor layer sub-pixels or simply sub-pixels) and the emissive layer may be referred to as having emissive layer sub-pixels (sometimes referred to as emissive pixels, emissive sub-pixels or simply sub-pixels). 
     The thin-film transistor sub-pixels used to control the emissive sub-pixels in high transmittance region  332  may be consolidated in a transition area of the display that does not overlap sensor  13 . This increases the transparency of the display over sensor  13 . Signal lines may be used to electrically connect thin-film transistor sub-pixels to their respective emissive sub-pixels that overlap sensor  13 . 
       FIG.  7    is a top view of display  14  showing touch sensor metal in full pixel density region  334 . As shown in  FIG.  7   , a touch sensor electrode  112  is formed over emissive sub-pixels (sometimes referred to simply as pixels) in full pixel density region  334 . As discussed in connection with  FIG.  3   , one or more touch layers  316  that implement the touch sensor functions of touch-screen display  14  may be formed over polarizer films  312  using adhesive  314  (e.g., OCA material). The touch layers therefore are formed over the emissive material (e.g., emissive material  306 - 2  in  FIG.  4   ) of the pixels. Touch layers  316  may include electrodes (e.g., horizontal touch sensor electrodes and/or vertical touch sensor electrodes) such as electrode  112  in  FIG.  7   . Electrode  112  may be part of an array of capacitive touch sensor electrodes. 
     The touch sensor electrode may be formed from a conductive material such as metal. The touch sensor electrode may be opaque (e.g., with a transmission of less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, less than 3%, less than 1%, etc.). Accordingly, the touch sensor metal is positioned to not overlap the pixels in the light emitting direction (e.g., in the Z-direction in  FIG.  7   ). As shown in  FIG.  7   , in the full pixel density region  334 , touch sensor electrode  112  (sometimes referred to as touch sensor metal  112 ) may be formed as a mesh that defines a plurality of openings. Each opening overlaps a respective emissive sub-pixel  114  in the Z-direction and is aligned with that respective emissive sub-pixel  114  within the XY-plane. Each emissive sub-pixel is aligned with an opening in the touch sensor electrode such that the emissive sub-pixel is not directly vertically overlapped by the touch sensor electrode. 
       FIG.  8    is a top view of display  14  showing touch sensor metal in pixel removal region  332 . In this example, the touch sensor electrode  112  has the same arrangement as in full pixel density region  334 . Therefore, the touch sensor electrode  112  in pixel removal region  332  is formed as a mesh that defines a plurality of openings. Some of the openings overlap (in the Z-direction) and are aligned with the emissive sub-pixels  114  that remain present in pixel removal region  332 . Some of the openings overlap the position of emissive sub-pixels that are removed in pixel removal region  332 . For example, touch sensor electrode  112  in  FIG.  8    defines an opening  116 - 1  that overlaps a blue emissive sub-pixel that is present in pixel removal region  332 . Touch sensor electrode  112  in  FIG.  8    also defines an opening  116 - 2  that does not overlap any emissive sub-pixels. If no sub-pixels were removed in pixel removal region  332 , opening  116 - 2  would overlap and be aligned with a blue emissive sub-pixel. Even though the corresponding blue emissive sub-pixel is removed in region  332 , the opening is still present. 
     Including a touch sensor electrode in pixel removal region  332  with the same arrangement as in full pixel density region  334  may maximize the touch sensing performance in region  332  of display  14 . However, the presence of touch sensor metal in pixel removal region  332  undesirably blocks light from passing through the display, reducing the overall transmittance of pixel removal region  332 . Removing some of the touch sensor metal improves the transmission through the display (which is better for performance of a camera or other sensor that operates through the display) but reduces touch sensor performance. Including more touch sensor metal improves touch sensor performance but reduces transmission through the display (which is worse for performance of a camera or other sensor that operates through the display). 
     To optimize both touch sensing performance and transmission through the display, the arrangement of the touch sensor metal in pixel removal region  332  may be modified relative to the arrangement of the touch sensor metal in full pixel density region  334 . To improve transmission while maintaining satisfactory touch sensing performance, one or more segments of the touch sensor metal in region  332  may have a reduced width relative to the touch sensor metal in region  334  (as in  FIG.  9   ) and/or one or more segments of the touch sensor metal in region  332  may be omitted relative to the touch sensor metal in region  334  (as in  FIGS.  10 - 13   ). In general, the total coverage per unit area of the touch sensor metal (i.e., the total surface area of the touch sensor metal divided by the total surface area of the unit area) in region  332  may be lower than in region  334  to increase transmittance in region  332 . 
       FIG.  9    is a top view of display  14  showing touch sensor metal in pixel removal region  332 . In this example, the touch sensor metal  112  has one or more segments with a reduced width relative to the touch sensor metal in region  334 . In  FIG.  9   , as in  FIG.  8   , the touch sensor electrode  112  is formed as a mesh that defines a plurality of openings. Some of the openings overlap (in the Z-direction) and are aligned with the emissive sub-pixels  114  that remain present in pixel removal region  332 . Some of the openings overlap the position of emissive sub-pixels that are removed in pixel removal region  332 . For example, touch sensor electrode  112  in  FIG.  9    defines an opening  116 - 1  that overlaps a blue emissive sub-pixel that is present in pixel removal region  332 . Touch sensor electrode  112  in  FIG.  9    also defines an opening  116 - 2  that does not overlap any emissive sub-pixels. 
     Some of the segments of touch sensor electrode  112  in  FIG.  9    (e.g., segments  118 - 1  and  118 - 2 ) have a first width. Some of the segments of touch sensor electrode  112  in  FIG.  9    (e.g., segments  118 - 3  and  118 - 4 ) have a second width. The first width is larger than the second width. In the full pixel density region  334 , all of the touch sensor metal segments may have the first width. In the pixel removal region  332 , only some of the touch sensor metal segments may have the first width. As one example, shown in  FIG.  9   , touch sensor metal segments that are directly adjacent to an edge of an emissive sub-pixel may have the first width. Touch sensor metal segments that are not directly adjacent to an edge of an emissive sub-pixel (e.g., segments  118 - 3  and  118 - 4 ) have the second width. 
     The difference between the first and second widths may be greater than 0.1 microns, greater than 0.5 microns, greater than 1 micron, greater than 2 microns, greater than 5 microns, between 0.1 micron and 2 microns, less than 2 microns, etc. The magnitude of the first width may be greater than 2 microns, greater than 3 microns, greater than 5 microns, less than 10 microns, less than 5 microns, less than 3 microns, between 2 microns and 4 microns, etc. The magnitude of the second width may be greater than 1 micron, greater than 2 microns, greater than 3 microns, less than 5 microns, less than 3 microns, less than 2 microns, between 1 micron and 3 microns, etc. 
     Narrowing some but not all of the touch sensor metal segments in pixel removal region  332  relative to full pixel density region  334  may increase the overall transmittance of pixel removal region  332 . For example, the transmittance in pixel removal region  332  in  FIG.  9    may be at least 1% greater than the transmittance in pixel removal region in  FIG.  8   , at least 2% greater than the transmittance in pixel removal region in  FIG.  8   , etc. 
     In another possible arrangement, all of the touch sensor metal segments in region  332  may have the second width (that is smaller than the first width used in region  334 ). 
     In  FIG.  9   , the total coverage of touch sensor metal per unit area in pixel removal region  332  is lower (e.g., greater than 10% lower, greater than 20% lower, greater than 30% lower, greater than 50% lower, greater than 75% lower, etc.) than the total coverage of touch sensor metal per unit area in full pixel density region  334  (in  FIG.  7   ). 
       FIG.  10    is a top view of display  14  showing another arrangement for touch sensor metal in pixel removal region  332 . In this example, the touch sensor electrode  112  has one or more segments omitted relative to the touch sensor metal in region  334 . In  FIG.  10   , each emissive sub-pixel  114  is laterally surrounded by 4 touch sensor metal segments. In other words, each emissive sub-pixel is positioned within a respective opening in a mesh formed by touch sensor electrode  112 . 
     However, unlike in  FIG.  8   , touch sensor electrode  112  does not define openings around the locations of omitted emissive sub-pixels. In general, the touch sensor metal segments that would normally be present around the omitted emissive sub-pixels are omitted. Touch sensor electrode  112  may be considered to have respective portions  120  that overlap the emissive sub-pixels that are included in pixel removal region  332 . For example, portion  120 - 1  forms a mesh that defines openings for each emissive sub-pixel in a single first zigzag row of emissive sub-pixels and portion  120 - 2  forms a mesh that defines openings for each emissive sub-pixel in a single second zigzag row of emissive sub-pixels. 
     In  FIG.  10   , intermittent touch sensor metal segments  122  are included to electrically connect portions  120  of the touch sensor metal. Including touch sensor metal segments  122  ensures that portions  120  are electrically connected, reducing sheet resistance across electrode  112  and improving current distribution across electrode  112 . In  FIG.  10   , one connecting segment  122  is included for every four lateral emissive sub-pixels in a given zigzag row. This example is merely illustrative. In general, any desired number of connecting segments  122  may be included in the touch sensor electrode. Similarly, in  FIG.  10    a first row of connecting segments is aligned (along the X-direction) with a second row of connecting segments. This example is merely illustrative. If desired, a first row of connecting segments may be offset (along the X-direction) relative to a second row of connecting segments. 
     The touch sensor electrode of  FIG.  7    defines a mesh with a first number of openings per unit area. The touch sensor electrode of  FIG.  10    defines a mesh with a second number of openings per unit area that is lower than the first number of openings per unit area. The total coverage of touch sensor metal per unit area in pixel removal region  332  in  FIG.  10    is lower (e.g., greater than 10% lower, greater than 20% lower, greater than 30% lower, greater than 50% lower, greater than 75% lower, etc.) than the total coverage of touch sensor metal per unit area in full pixel density region (in  FIG.  7   ). This relationship of a lower total coverage per unit area in the pixel removal region holds true for the touch sensor metal in  FIGS.  9 - 14    (relative to the full pixel density region touch sensor metal of  FIG.  7   ). 
     The arrangement in  FIG.  10    is merely illustrative. If desired, additional, fewer, or different touch sensor metal segments may be omitted.  FIG.  11    is a top view of a touch sensor electrode  112  with additional segments omitted relative to  FIG.  10   . In  FIG.  11   , touch sensor electrode  112  has portions  120  that define openings for some but not all of the emissive sub-pixels that are included in pixel removal region  332 . For example, portion  120 - 1  forms a mesh that defines openings for each red and blue emissive sub-pixel in a first zigzag row of emissive sub-pixels and portion  120 - 2  forms a mesh that defines openings for each red and blue emissive sub-pixel in a second zigzag row of emissive sub-pixels. Portions  120 - 1  and  120 - 2  do not define openings for the green emissive sub-pixels in  FIG.  11   . 
     In  FIG.  11   , intermittent touch sensor metal segments  122  are included to electrically connect portions  120  of the touch sensor metal. Including touch sensor metal segments  122  ensures that portions  120  are electrically connected, reducing sheet resistance across electrode  112  and improving current distribution across electrode  112 . In  FIG.  11   , one connecting segment  122  is included for every four lateral emissive sub-pixels in a given zigzag row. This example is merely illustrative. In general, any desired number of connecting segments  122  may be included in the touch sensor electrode. Similarly, in  FIG.  11    a first row of connecting segments is aligned (along the X-direction) with a second row of connecting segments. This example is merely illustrative. If desired, a first row of connecting segments may be offset (along the X-direction) relative to a second row of connecting segments. 
       FIG.  12    is a top view of a touch sensor electrode  112  with additional segments omitted relative to  FIG.  11   . In  FIG.  12   , touch sensor electrode  112  has portions  120  that define openings that overlap some but not all of the emissive sub-pixels that are included in pixel removal region  332 . For example, portion  120 - 1  forms a mesh that defines openings for each red and blue emissive sub-pixel in a first zigzag row of emissive sub-pixels and portion  120 - 2  forms a mesh that defines openings for each red and blue emissive sub-pixel in a second zigzag row of emissive sub-pixels. Portions  120 - 1  and  120 - 2  do not define openings for the green emissive sub-pixels in  FIG.  12   . The connecting segments  122  from  FIGS.  10  and  11    are omitted in  FIG.  12    to further improve the transmittance of pixel removal region  332 . 
       FIG.  13    is a top view of a touch sensor electrode  112  with additional segments omitted relative to  FIG.  12   . In  FIG.  13   , touch sensor electrode  112  has zigzag portions  120  that overlap the space between emissive sub-pixels  114  in pixel removal region  332 . For example, portion  120 - 1  forms a zigzag line with some segments (e.g., segment  118 - 1 ) that are interposed between green and blue emissive sub-pixels and some segments (e.g., segments  118 - 2 ) that are interposed between green and red emissive sub-pixels. The connecting segments  122  from  FIGS.  10  and  11    are omitted in  FIG.  13    to further improve the transmittance of pixel removal region  332 . 
     When connecting segments are not included in the touch sensor electrode (as in  FIGS.  12  and  13   ), the touch sensor electrode may have one more conductive structures at its periphery to electrically connect portions  120 . Alternatively, portions  120  may not be electrically connected and may each serve as individual touch sensor electrodes. 
     Connecting segments  122  (as in  FIGS.  10  and  11   ) may optionally be included between portions  120  in the touch sensor metal of  FIGS.  12  and  13    if desired. 
     It should further be noted that any of the touch sensor electrodes in  FIGS.  10 - 13    (with omitted portions relative to the full pixel density region  334 ) may include one or more narrow segments (as in  FIG.  9   ) to further improve transmittance. In other words, any of the arrangements of  FIGS.  10 - 13    may be combined with the narrow segments of  FIG.  9    if desired. 
     In  FIGS.  10 - 13   , the total coverage of touch sensor metal per unit area in pixel removal region  332  is lower (e.g., greater than 10% lower, greater than 20% lower, greater than 30% lower, greater than 50% lower, greater than 75% lower, etc.) than the total coverage of touch sensor metal per unit area in full pixel density region  334  (in  FIG.  7   ). 
       FIG.  14    is a top view showing how pixels may be removed to form the pattern used in pixel removal region  332 . Layout  132  shows the arrangement of red (R), blue (B), and green (G) pixels in a full pixel density region  334 . To obtain the layout for the pixel removal region  332 , certain pixels (marked with X&#39;s) are removed. To provide a uniform distribution of pixels across the display surface, an intelligent pixel removal process may be implemented that systematically eliminates the closest pixel of the same color (e.g., the nearest neighbor of the same color may be removed). The pixel removal process may involve, for each color, selecting a given pixel, identifying the closest or nearest neighboring pixels of the same color (in terms of distance from the selected pixel), and then eliminating/omitting those identified pixels in the final pixel removal region. 
     The pixel removal process produces layout  134  (with zigzag rows of pixels). As previously shown and discussed, the pixels in the pixel removal region  332  may use layout  134  (shown in  FIG.  14   ). 
     As shown by layout  132 , each green emissive sub-pixel has a non-square rectangular shape with a width (W) and length (L) in the full pixel density region  334  (e.g., before pixels are removed). Although the magnitude of the width and the magnitude of the length of the green emissive sub-pixels are the same across the layout, there are green emissive sub-pixels with two different orientations. Some of the green emissive sub-pixels (e.g., pixels  114 - 1 ) have lengths that extend from the upper left to the lower right. In other words, these lengths extend in the negative Y-direction when extending in the positive X-direction. Some of the green emissive sub-pixels (e.g., pixels  114 - 2 ) have lengths that extend from the lower left to the upper right. In other words, these lengths extend in the positive Y-direction when extending in the positive X-direction. Half of the pixels (e.g., pixels  114 - 1 ) may have the first orientation and the other half of the pixels (e.g., pixels  114 - 2 ) may have the second orientation. 
     As shown in  FIG.  14   , during the pixel removal process, all of the green emissive sub-pixels  114 - 2  are removed while all of the green emissive sub-pixels  114 - 1  remain. Accordingly, all of the green emissive sub-pixels in layout  134  (which is used in pixel removal region  332 ) have the first orientation (with lengths that extend from the upper left to the lower right). In contrast, the full pixel density region  334  includes an even distribution of green emissive sub-pixels of both orientations. If care is not taken, this may result in a difference in off-axis color shift between full pixel density region  334  and pixel removal region  332 . This may result in pixel removal region  332  having a different appearance than full pixel density region  334  at off-axis viewing angles. 
     To mitigate a different appearance between pixel removal region  332  and full pixel density region  334  at off-axis viewing angles, the position of the touch sensor metal in pixel removal region  332  may be tuned.  FIGS.  15 - 17    show examples of this type. 
     For reference,  FIG.  15    shows the spacing between emissive sub-pixels and the touch sensor metal in full pixel density region  334  of the display. As shown, each emissive sub-pixel has four sides. Each side is adjacent to a respective segment of touch sensor electrode  114 . As shown in  FIG.  15   , each green emissive sub-pixel has a first side separated from a respective touch sensor metal segment by distance D 1 , a second side separated from a respective touch sensor metal segment by distance D 2 , a third side separated from a respective touch sensor metal segment by distance D 3 , and a fourth side separated from a respective touch sensor metal segment by distance D 4 . Distances D 1 -D 4  may have the same magnitudes or may have different magnitudes. Distances D 1 -D 4  may be the same for each green emissive sub-pixel (in one possible arrangement). Alternatively, different green emissive sub-pixels may have different magnitudes for one or more of D 1 -D 4 . 
     As shown in  FIG.  15   , each blue emissive sub-pixel has a first side separated from a respective touch sensor metal segment by distance D 5 , a second side separated from a respective touch sensor metal segment by distance D 6 , a third side separated from a respective touch sensor metal segment by distance D 7 , and a fourth side separated from a respective touch sensor metal segment by distance D 8 . Distances D 5 -D 8  may have the same magnitudes or may have different magnitudes. Distances D 5 -D 8  may be the same for each blue emissive sub-pixel (in one possible arrangement). Alternatively, different blue emissive sub-pixels may have different magnitudes for one or more of D 5 -D 8 . 
     As shown in  FIG.  15   , each red emissive sub-pixel has a first side separated from a respective touch sensor metal segment by distance D 9 , a second side separated from a respective touch sensor metal segment by distance D 10 , a third side separated from a respective touch sensor metal segment by distance D 11 , and a fourth side separated from a respective touch sensor metal segment by distance D 12 . Distances D 9 -D 12  may have the same magnitudes or may have different magnitudes. Distances D 9 -D 12  may be the same for each red emissive sub-pixel (in one possible arrangement). Alternatively, different red emissive sub-pixels may have different magnitudes for one or more of D 9 -D 12 . 
     Each one of distances D 1 -D 4  may be greater than 0.1 microns, greater than 0.5 microns, greater than 1 micron, greater than 2 microns, greater than 5 microns, greater than 10 microns, between 1 micron and 10 microns, less than 10 microns, less than 5 microns, etc. 
     To mitigate color differences between pixel removal region  332  and full pixel density region  334 , the position of some of the touch sensor metal segments may be shifted in pixel removal region  332 .  FIG.  16    shows the spacing between emissive sub-pixels and the touch sensor metal in pixel removal region  332  of the display. In  FIG.  16   , some of the touch sensor metal segments are removed (similar to as in  FIG.  10   , for example). In addition, some of the touch sensor metal segments that are present in pixel removal region  332  are shifted relative to their position in full pixel density region  334  to mitigate color differences between pixel removal region  332  and full pixel density region  334 . 
     As shown in  FIG.  16   , each blue emissive sub-pixel has a first side separated from a respective touch sensor metal segment by distance D 5 , a second side separated from a respective touch sensor metal segment by distance D 6 , a third side separated from a respective touch sensor metal segment by distance D 7 , and a fourth side separated from a respective touch sensor metal segment by distance D 8 . Distances D 5 -D 8  may have the same magnitudes or may have different magnitudes. Distances D 5 -D 8  may be the same for each blue emissive sub-pixel (in one possible arrangement). Alternatively, different blue emissive sub-pixels may have different magnitudes for one or more of D 5 -D 8 . 
     As shown in  FIG.  16   , each red emissive sub-pixel has a first side separated from a respective touch sensor metal segment by distance D 9 , a second side separated from a respective touch sensor metal segment by distance D 10 , a third side separated from a respective touch sensor metal segment by distance D 11 , and a fourth side separated from a respective touch sensor metal segment by distance D 12 . Distances D 9 -D 12  may have the same magnitudes or may have different magnitudes. Distances D 9 -D 12  may be the same for each red emissive sub-pixel (in one possible arrangement). Alternatively, different red emissive sub-pixels may have different magnitudes for one or more of D 9 -D 12 . 
     In other words, the relative spacing between the blue emissive sub-pixels and the red emissive sub-pixels and the touch sensor metal is the same in the pixel removal region as in the full pixel density region. However, the relative spacing between the green emissive sub-pixels and the touch sensor metal is different in the pixel removal region than in the full pixel density region. 
     Green emissive sub-pixels in  FIG.  16    have four sides each adjacent to a respective touch sensor metal segment. The touch sensor metal segments that are interposed between adjacent emissive sub-pixels (e.g., segment  118 - 1  between a green emissive sub-pixel and a blue emissive sub-pixel or segment  118 - 2  between a green emissive sub-pixel and a red emissive sub-pixel) may have the same spacing relative to the sub-pixels in pixel removal region  332  as in full pixel density region  334 . However, touch sensor metal segments that are adjacent to a green emissive sub-pixel but that are not interposed between adjacent emissive sub-pixels may be shifted in pixel removal region  332  relative to full pixel density region  334 . 
     For example, consider green emissive sub-pixel  114 - 1  in  FIG.  16   . The green emissive sub-pixel has a first side separated from a respective touch sensor metal segment by distance D 1 , a second side separated from a respective touch sensor metal segment by distance D 2 ′, a third side separated from a respective touch sensor metal segment by distance D 3 , and a fourth side separated from a respective touch sensor metal segment by distance D 4 ′. Distances D 1  and D 3  are the same in  FIG.  16    (in the pixel removal region) as in  FIG.  15    (in the full pixel density region). However, distances D 2 ′ and D 4 ′ in  FIG.  16    have different magnitudes than distances D 2  and D 4  in  FIG.  15   . A first touch sensor metal segment that extends from the lower left to the upper right (e.g., orthogonal to the length of the emissive sub-pixel) is shifted in direction  142  (towards the green emissive sub-pixel) to result in a modified distance D 4 ′ between that segment and the emissive sub-pixel. A second touch sensor metal segment that extends from the upper left to the lower right (parallel to the length of the emissive sub-pixel) is shifted in direction  144  (away from the green emissive sub-pixel) to result in a modified distance D 2 ′ between that segment and the emissive sub-pixel. This shift technique may be applied to all of the green emissive sub-pixels at a lower portion of each zigzag row. 
     The green emissive sub-pixels at an upper portion of each zigzag row may have a similar adjustment. In particular, distances D 1 ′ and D 3 ′ in  FIG.  16    have different magnitudes than distances D 1  and D 3  in  FIG.  15   . A first touch sensor metal segment that extends from the lower left to the upper right (e.g., orthogonal to the length of the emissive sub-pixel) is shifted in direction  142  (towards the green emissive sub-pixel) to result in a modified distance D 3 ′ between that segment and the emissive sub-pixel. A second touch sensor metal segment that extends from the upper left to the lower right (parallel to the length of the emissive sub-pixel) is shifted in direction  144  (away from the green emissive sub-pixel) to result in a modified distance D 1 ′ between that segment and the emissive sub-pixel. 
     To summarize, the touch sensor metal segments that are adjacent to the shorter side (e.g., parallel to the width and orthogonal to the length) of a green emissive sub-pixel without being interposed between adjacent emissive sub-pixels are shifted towards that green emissive sub-pixel. The touch sensor metal segments that are adjacent to the longer side (e.g., parallel to the length and orthogonal to the width) of a green emissive sub-pixel without being interposed between adjacent emissive sub-pixels are shifted away from that green emissive sub-pixel. This mitigates off-axis color shift between pixel removal region  332  and full pixel density region  334 . 
     Each shift amount (e.g., the difference between D 1  in region  334  and D 1 ′ in region  332 , the difference between D 2  in region  334  and D 2 ′ in region  332 , the difference between D 3  in region  334  and D 3 ′ in region  332 , and the difference between D 4  in region  334  and D 4 ′ in region  332 ) may have any desired magnitude (e.g., greater than 0.1 microns, greater than 0.5 microns, greater than 1 micron, greater than 2 microns, greater than 5 microns, between 0.1 micron and 2 microns, less than 2 microns, less than 5 microns, between 1 micron and 3 microns, etc. 
     In one possible arrangement, the difference between D 3  and D 3 ′ is the same as the difference between D 4  and D 4 ′ (since these are both shifts towards the emissive sub-pixel) and the difference between D 2  and D 2 ′ is the same as the difference between D 1  and D 1 ′ (since these are both shifts away from the emissive sub-pixel). 
     In addition to shifting some of the touch sensor metal segments (as in  FIG.  16   ), the touch sensor electrode may include some touch sensor metal segments that are wider than others to mitigate off-axis color shift between pixel removal region  332  and full pixel density region  334 .  FIG.  17    is a top view of a pixel removal region with wide touch sensor metal segments of this type. As shown in  FIG.  17   , each touch sensor metal segment  118  has an increased width relative to the rest of the touch sensor metal segments (and relative to the corresponding touch sensor metal segments in the full pixel density region as in  FIG.  15   ). The wide touch sensor metal segments  118  are adjacent to the shorter side (e.g., parallel to the width and orthogonal to the length) of a green emissive sub-pixel without being interposed between adjacent emissive sub-pixels. Each touch sensor metal segment  118  in this position may have an increased width W 2 . The remaining touch sensor metal segments in pixel removal region  332  have a width W 1 . All of the touch sensor metal segments in the full pixel density region  334  may have the width W 1 . 
     The difference between widths W 1  and W 2  may have any desired magnitude (e.g., greater than 0.1 microns, greater than 0.5 microns, greater than 1 micron, greater than 2 microns, greater than 5 microns, between 0.1 micron and 2 microns, less than 2 microns, less than 5 microns, between 1 micron and 3 microns, between 1 micron and 2 microns, etc.). The magnitude of W 1  may be greater than 2 microns, greater than 3 microns, greater than 5 microns, less than 10 microns, less than 5 microns, less than 3 microns, between 2 microns and 4 microns, etc. The magnitude of W 2  may be greater than 1 micron, greater than 2 microns, greater than 3 microns, greater than 4 microns, less than 5 microns, less than 10 microns, less than 3 microns, between 4 microns and 5 microns, etc. 
       FIGS.  16  and  17    show examples where the position of the touch sensor metal in pixel removal region  332  is tuned to mitigate a different appearance between pixel removal region  332  and full pixel density region  334  at off-axis viewing angles. It should further be noted that the position of the touch sensor metal in pixel removal region  332  and/or full pixel density region  334  may be tuned may be tuned to reduce color asymmetry induced by anode tilt in the pixels. 
     One or more of the techniques for reducing the amount touch sensor metal in pixel removal region  332  (as in  FIGS.  9 - 13   ) may be combined with one or more of the techniques for mitigating off-axis color shift between regions  332  and  334  (as in  FIGS.  16  and  17   ). Additionally, any of the aforementioned techniques may be applied to any display portion that overlaps an input-output component (regardless of the arrangement of the display pixels over the input-output component, whether or not the display has a reduced pixel density over the input-output component, etc.). 
     Instead of or in addition to including the aforementioned touch sensor metal concepts (e.g., reducing touch sensor metal in the pixel removal region and/or tuning the touch sensor metal spacing), an additional touch sensor metal patch may be included in the touch sensor metal to block a reflective structure underneath the display.  FIG.  18 A  is a top view of an illustrative display with touch sensor metal. As shown in  FIG.  18 A , display  14  includes an active area (AA) with display pixels  22  (as shown in  FIG.  2   , for example) and an inactive area without display pixels that emit light for the display. A signal line such as signal line  402  may be included in the inactive area of the display. Signal line  402  may provide a signal (e.g., an initialization voltage) to the pixels  22  within the active area AA. Signal line  402  has a linear portion  402 -L that extends vertically along a left side of the active area and a curved portion  402 -C that extends from the linear portion around a rounded corner of the active area. 
       FIG.  18 A  also shows how touch sensor metal  112  is arranged in a repeating pattern over the display. The touch sensor metal may have portions that overlap the active area (AA) and portions that overlap the inactive area of the display. 
       FIG.  18 B  is a cross-sectional side view of the display of  FIG.  18 A  showing signal line  402 . Signal line  402  may be formed on a substrate  408  and/or planarization layers  406 . One or more planarization layers  404  is formed over the signal line. The signal line is also covered by encapsulation layer(s)  308 , polarizer  312 , and display cover layer  320 . In this example, touch sensor metal  112  is interposed between polarizer  312  and encapsulation layer(s)  308 . In  FIGS.  18 A and  18 B , touch sensor metal  112  has little to no overlap with signal line  402 . 
     Signal line  402  may be formed from a reflective material (e.g., having a reflectance that is greater than 60%, greater than 80%, greater than 90%, greater than 95%, etc.). Reflections from planar portions of signal line  402  (e.g., portions parallel to the XY-plane) may be blocked by polarizer  312 . However, signal line  402  has non-planar portions  402 -NP due to the geometry of underlying planarization layers  406 . The non-planar portions  402 -NP may cause reflections that are not blocked by polarizer  312 . This may cause the display to have a bright line overlapping the footprint of signal line  402  when viewed by a viewer in bright ambient light conditions. 
     As shown in  FIGS.  19 A and  19 B , to mitigate reflections of this type, the touch sensor metal  112  may include a patch  112 -P in addition to the repeating pattern from  FIG.  18 A . Patch  112 -P in  FIG.  19 A  may have a footprint that overlaps (is aligned with) signal line  402 . The patch may have a linear portion that extends vertically along a left side of the active area (to overlap linear portion  402 -L of signal line  402 ) and a curved portion that extends from the linear portion around a rounded corner of the active area (to overlap curved portion  402 -C of signal line  402 ). 
     As shown in  FIG.  19 B , touch sensor metal patch  112 -P overlaps signal line  402 . Ambient light therefore reflects off of the planar touch sensor metal patch  112 -P (instead of the non-planar portions of the signal line  402 ) and are blocked by polarizer  312 . Touch sensor metal patch  112 -P is electrically connected to (and formed during the same manufacturing step as) the repeating pattern portion of the touch sensor metal. 
     In the repeating pattern portion of the touch sensor metal  112  (e.g., the grid shown in  FIG.  18 A ), each segment of touch sensor metal may have a first width that is less than 10 microns, less than 5 microns, less than 3 microns, greater than 1 micron, between 1 micron and 10 microns, between 2 microns and 5 microns, etc. The patch  112 -P may have a second width that is greater than 10 microns, greater than 20 microns, greater than 30 microns, greater than 50 microns, less than 50 microns, between 20 microns and 30 microns, etc. The second width may be at least 50% greater than the first width, at least two times greater than the first width, at least five times greater than the first width, at least ten times greater than the first width, etc. 
     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: 20220616
Publication Date: 20230905
Grant Date: 20230905
Priority Date: 20220301
Inventors: PETERSON, RICARDO A
JAMSHIDI ROUDBARI, ABBAS
GOGTE, Ashray Vinayak
BLONDIN, Christophe
KNITTER, Sebastian
RIEUTORT-LOUIS, Warren S
CHE, Yuchi
MOROZOV, YURII
Hollands, Matthew D
QIAN, Chuang
Lim, Michael H
SCHWENDEMAN, MATTHEW J
KIM, Kenny
TSAI, TSUNG-TING
QU, Yue
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/131", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/352", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0448", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/131", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/352", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 85328905