PATENT DOCUMENT

Publication Number: US-12045427-B2
Application Number: US-202318154693-A
Country: US
Kind Code: B2

Title: Touch electrodes with bar and stripe pattern

Abstract:
This relates to touch sensor panels/touch screens including touch electrodes in a bar-and-stripe pattern. The bar-and-stripe pattern can improve touch signal levels for touch detection and improve uniformity of touch signal as objects move across the touch sensor panel/touch screen. Touch electrodes in a bar-and-stripe pattern can be formed from metal mesh in one or more layers of metal mesh. In some examples, “stripes” can be formed from groups of touch electrode segments in a first layer of metal mesh and can be interconnected by bridges formed in a second layer of metal mesh, different from the first layer of metal mesh, in the active area of the touch screen. Multiple stripes can be interconnected in the border area and/or in the active area to form a row touch electrode. In some examples, “bars” may also include bridges in the second layer of metal mesh.

Claims:
The invention claimed is: 
     
       1. A touch screen comprising:
 a display having an active area; and 
 a plurality of touch electrodes formed over the active area of the display, comprising:
 one or more contiguous column touch electrodes in a first layer that extend along a first direction; and 
 one or more row touch electrodes including a first row touch electrode, the one or more row touch electrodes comprising a plurality of touch electrode segments in the first layer that extend along a second direction that is different from the first direction; 
 wherein:
 each pair of touch electrode segments of the first row touch electrode that are aligned along the first direction has respective first and second edges that face each other; and 
 one or more portions of the one or more contiguous column touch electrodes separate the respective first and second edges of each pair of touch electrode segments of the first row touch electrode that are aligned along the first direction, including at least a first portion of one of the one or more contiguous column touch electrodes that separates the respective first and second edges of a first pair of touch electrode segments of the first row touch electrode that are aligned along the first direction and at least a second portion of the one of the one or more contiguous column touch electrodes that separates the respective first and second edges of a second pair of touch electrode segments of the first row touch electrode that are aligned along the first direction. 
 
 
 
     
     
       2. The touch screen of  claim 1 , wherein the first row touch electrode comprises:
 a two dimensional array of touch electrode segments of the plurality of touch electrode segments. 
 
     
     
       3. The touch screen of  claim 2 , wherein the two dimensional array of the touch electrode segments comprises:
 a first one dimensional array of the touch electrode segments; and 
 a second one dimensional array of the touch electrode segments electrically isolated from the first one dimensional array within the active area of the display. 
 
     
     
       4. The touch screen of  claim 3 , wherein the one or more contiguous column touch electrodes comprise:
 a first column touch electrode in a first region between a first vertical boundary and a second vertical boundary; and 
 a second column touch electrode in a second region between a third vertical boundary and a fourth vertical boundary, wherein:
 a first touch electrode segment of the first one dimensional array includes a first side and a second side opposite from the first side, the first side entirely within the first region, and the second side entirely within the second region. 
 
 
     
     
       5. The touch screen of  claim 3 , wherein the one or more contiguous column touch electrodes comprise:
 a first column touch electrode in a region between a first vertical boundary and a second vertical boundary, wherein:
 a first touch electrode segment of the first one dimensional array includes a first side and a second side opposite from the first side; and 
 the first side and second side are entirely within the region. 
 
 
     
     
       6. The touch screen of  claim 1 , wherein the first layer comprises a first metal mesh layer, and wherein the plurality of touch electrodes is formed of metal mesh disposed in the first metal mesh layer disposed over the active area of the display, and the touch screen further comprises:
 a plurality of bridges formed at least partially in a second metal mesh layer different from the first metal mesh layer, wherein a bridge of the plurality of bridges electrically couples two of the plurality of touch electrode segments along the second direction. 
 
     
     
       7. The touch screen of  claim 6 , wherein the first row touch electrode includes a two dimensional array of touch electrode segments of the plurality of touch electrode segments, the two dimensional array of the touch electrode segments comprising:
 a first one dimensional array of the touch electrode segments; and 
 a second one dimensional array of the touch electrode segments electrically isolated from the first one dimensional array within the active area of the display, wherein:
 the first one dimensional array of the touch electrodes includes a first group of the plurality of touch electrode segments disposed along the second direction that are electrically coupled by one or more first bridges of the plurality of bridges; and 
 the second one dimensional array of the touch electrodes includes a second group of the plurality of touch electrode segments, different from and disposed parallel to the first group of the plurality of touch electrode segments, that are electrically coupled by one or more second bridges of the plurality of bridges. 
 
 
     
     
       8. The touch screen of  claim 7 , wherein:
 the first group of the touch electrodes segments and the second group of the touch electrode segments are electrically coupled via a conductor disposed in a border region around the active area of the display. 
 
     
     
       9. The touch screen of  claim 7 , wherein:
 a respective touch node of the touch screen corresponds to adjacency of one of the one or more contiguous column touch electrodes and a portion of the first row touch electrode; and 
 the portion of the first row touch electrode comprises:
 three touch electrode segments of the first group that are electrically coupled by two bridges of the first bridges; and 
 three touch electrode segments of the second group that are electrically coupled by two bridges of the second bridges. 
 
 
     
     
       10. The touch screen of  claim 7 , wherein:
 a respective touch node of the touch screen corresponds to adjacency of one of the one or more contiguous column touch electrodes and a portion of the first row touch electrode; and 
 the portion of the first row touch electrode comprises:
 two touch electrode segments of the first group that are electrically coupled by a first bridge of the first bridges; and 
 two touch electrode segments of the second group that are electrically coupled by a second bridge of the second bridges. 
 
 
     
     
       11. The touch screen of  claim 1 , further comprising:
 one or more buffer electrodes disposed between one or more portions of the one or more contiguous column touch electrodes and one or more portions of the plurality of touch electrode segments, wherein the one or more buffer electrodes are floating, grounded, or driven with a potential. 
 
     
     
       12. The touch screen of  claim 1 , wherein the first layer comprises a first metal mesh layer, and wherein the plurality of touch electrodes is formed of metal mesh disposed in the first metal mesh layer disposed over the active area of the display, and the touch screen further comprises:
 a plurality of bridges formed at least partially in a second metal mesh layer different from the first metal mesh layer, wherein a bridge of the plurality of bridges electrically couples two of the plurality of touch electrode segments along the second direction; 
 a neck region between two of the plurality of touch electrode segments that tapers from a first width to a second width less than the first width; and 
 a length of the bridge of the plurality of bridges that electrically couples the two of the plurality of touch electrode segments across the neck region is greater than or equal to the second width and less than the length of the first width. 
 
     
     
       13. The touch screen of  claim 1 , wherein:
 the first layer comprises a first metal mesh layer; 
 the plurality of touch electrodes is formed of metal mesh disposed in a first metal mesh layer disposed over the active area of the display; and 
 electrical discontinuities in the first metal mesh layer form boundaries between one of the one or more contiguous column touch electrodes and one or more touch electrode segments of the plurality of touch electrode segments, and wherein the boundaries are a zig-zag pattern. 
 
     
     
       14. The touch screen of  claim 1 , wherein:
 the first layer comprises a first metal mesh layer; 
 the plurality of touch electrodes is formed of metal mesh disposed in a first metal mesh layer disposed over the active area of the display; 
 the metal mesh of one of the one or more contiguous column touch electrodes is at a same electrical potential relative to a reference potential; and 
 the metal mesh of the one of the one or more contiguous column touch electrodes includes electrical discontinuities internal to an area of the one of the one or more contiguous column touch electrodes. 
 
     
     
       15. The touch screen of  claim 1 , wherein:
 the first layer comprises a first metal mesh layer; 
 the plurality of touch electrodes is formed of metal mesh disposed in a first metal mesh layer disposed over the active area of the display; 
 the metal mesh of one of the plurality of touch electrode segments is at a same electrical potential relative to a reference potential; and 
 the metal mesh of the one of the plurality of touch electrode segments includes electrical discontinuities internal to an area of the one of the plurality of touch electrode segments. 
 
     
     
       16. The touch screen of  claim 1 , wherein a pattern of electrical discontinuities internal to an area of one of the plurality of touch electrodes repeats across the area of the one of the plurality of touch electrodes. 
     
     
       17. The touch screen of  claim 1 , wherein:
 the first layer comprises a first metal mesh layer; 
 the plurality of touch electrodes is formed of metal mesh disposed in a first metal mesh layer disposed over the active area of the display; 
 the metal mesh of one of the one or more contiguous column touch electrodes is at a same electrical potential relative to a reference potential; 
 a first region of the metal mesh of the one of the one or more contiguous column touch electrodes includes electrical discontinuities internal to an area of the one of the one or more contiguous column touch electrodes; 
 a second region of the metal mesh of the one of the one or more contiguous column touch electrodes does not include electrical discontinuities internal to the area of the one of the one or more contiguous column touch electrodes; and 
 the second region corresponds to a neck region between two of the plurality of touch electrode segments. 
 
     
     
       18. A touch-sensitive device comprising:
 an energy storage device; 
 communication circuitry; 
 a touch controller; and 
 a touch screen comprising:
 a display having an active area; and 
 a plurality of touch electrodes formed over the active area of the display, comprising:
 one or more contiguous column touch electrodes in a first layer that extend along a first direction; and 
 one or more row touch electrodes including a first row touch electrode, the one or more row touch electrodes comprising a plurality of touch electrode segments in the first layer that extend along a second direction that is different from the first direction; 
 wherein:
 each pair of touch electrode segments of the first row touch electrode that are aligned along the first direction has respective first and second edges that face each other; and 
 one or more portions of the one or more contiguous column touch electrodes separate the respective first and second edges of each pair of touch electrode segments of the first row touch electrode that are aligned along the first direction including at least a first portion of one of the one or more contiguous column touch electrodes that separates the respective first and second edges of a first pair of touch electrode segments of the first row touch electrode that are aligned along the first direction and at least a second portion of the one of the one or more contiguous column touch electrodes that separates the respective first and second edges of a second pair of touch electrode segments of the first row touch electrode that are aligned along the first direction. 
 
 
 
 
     
     
       19. The touch screen of  claim 18 , wherein the first layer comprises a first metal mesh layer, and wherein the plurality of touch electrodes is formed of metal mesh disposed in the first metal mesh layer disposed over the active area of the display, and the touch screen further comprises:
 a plurality of bridges formed at least partially in a second metal mesh layer different from the first metal mesh layer, wherein a bridge of the plurality of bridges electrically couples two of the plurality of touch electrode segments along the second direction. 
 
     
     
       20. The touch screen of  claim 19 , wherein the first row touch electrode includes a two dimensional array of touch electrode segments of the plurality of touch electrode segments, the two dimensional array of the touch electrode segments comprising:
 a first one dimensional array of the touch electrode segments; and 
 a second one dimensional array of the touch electrode segments electrically isolated from the first one dimensional array within the active area of the display, wherein:
 the first one dimensional array of the touch electrodes includes a first group of the plurality of touch electrode segments disposed along the second direction that are electrically coupled by one or more first bridges of the plurality of bridges; and 
 the second one dimensional array of the touch electrodes includes a second group of the plurality of touch electrode segments, different from and disposed parallel to the first group of the plurality of touch electrode segments, that are electrically coupled by one or more second bridges of the plurality of bridges.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/998,812, filed Aug. 20, 2020, and published on Aug. 5, 2021 as U.S. Publication No. 2021-0240303, which claims the benefit under 35 USC 119(e) of U.S. Provisional Application No. 62/969,652, filed Feb. 3, 2020, the contents of which are incorporated herein by reference in their entireties for all purposes. 
    
    
     FIELD OF THE DISCLOSURE 
     This relates generally to touch sensor panels, and more particularly to touch sensor panels including touch electrodes with a bar-and-stripe pattern. 
     BACKGROUND OF THE DISCLOSURE 
     Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch screens, in particular, are popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device such as a liquid crystal display (LCD), light emitting diode (LED) display or organic light emitting diode (OLED) display that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch and the position of the touch on the touch sensor panel, and the computing system can then interpret the touch in accordance with the display appearing at the time of the touch, and thereafter can perform one or more actions based on the touch. In the case of some touch sensing systems, a physical touch on the display is not needed to detect a touch. For example, in some capacitive-type touch sensing systems, fringing electrical fields used to detect touch can extend beyond the surface of the display, and objects approaching near the surface may be detected near the surface without actually touching the surface. 
     Capacitive touch sensor panels can be formed by a matrix of partially or fully transparent or non-transparent conductive plates (e.g., touch electrodes) made of materials such as Indium Tin Oxide (ITO). In some examples, the conductive plates can be formed from other materials including conductive polymers, metal mesh, graphene, nanowires (e.g., silver nanowires) or nanotubes (e.g., carbon nanotubes). It is due in part to their substantial transparency that some capacitive touch sensor panels can be overlaid on a display to form a touch screen, as described above. Some touch screens can be formed by at least partially integrating touch sensing circuitry into a display pixel stackup (i.e., the stacked material layers forming the display pixels). 
     BRIEF SUMMARY OF THE DISCLOSURE 
     This relates to touch sensor panels/touch screens including touch electrodes in a bar-and-stripe pattern. The bar-and-stripe pattern can improve touch signal levels for touch detection and improve uniformity of touch signal as objects move across the touch sensor panel/touch screen. Touch electrodes in a bar-and-stripe pattern can be formed from metal mesh in a single layer of metal mesh. In some examples, “stripes” can be formed from groups of touch electrode segments interconnected by bridges (formed in a second layer of metal mesh different from the first layer of metal mesh) in the active area of the touch screen (visible area of the display) and multiple stripes can be interconnected in the border area (outside of the visible area of the display) and/or in the active area to form a row touch electrode. In some examples, “bars” may also include bridges. To reduce the visibility of the metal mesh touch electrodes, the boundary between touch electrodes can be non-linear (with electrical discontinuities in the metal mesh in a non-linear pattern proceeding along the boundary) in some examples. In some examples, dummy cuts (electrical discontinuities in the metal mesh) can be made within an area of a touch electrode region (e.g., while maintaining the same electrical potential for the touch electrode region). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1 A- 1 E  illustrate example systems that can include a touch screen according to examples of the disclosure. 
         FIG.  2    illustrates an example computing system including a touch screen according to examples of the disclosure. 
         FIG.  3 A  illustrates an example touch sensor circuit corresponding to a self-capacitance measurement of a touch node electrode and sensing circuit according to examples of the disclosure. 
         FIG.  3 B  illustrates an example touch sensor circuit corresponding to a mutual-capacitance drive line and sense line and sensing circuit according to examples of the disclosure. 
         FIG.  4 A  illustrates touch screen with touch electrodes arranged in rows and columns according to examples of the disclosure. 
         FIG.  4 B  illustrates touch screen with touch node electrodes arranged in a pixelated touch node electrode configuration according to examples of the disclosure. 
         FIG.  5 A  illustrates an example touch screen stack-up including a metal mesh layer according to examples of the disclosure. 
         FIG.  5 B  illustrate top views of a portion of a touch screen according to examples of the disclosure. 
         FIGS.  6 A- 6 E  illustrate various example unit cells that can be repeated across a touch sensor panel to form a bar-and-stripe pattern according to examples of the disclosure. 
         FIG.  7    illustrates an example of a touch sensor panel formed from unit cells according to examples of the disclosure. 
         FIG.  8    illustrates a metal mesh corresponding to a portion of unit cell according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     In the following description of examples, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the disclosed examples. 
     This relates to touch sensor panels/touch screens including touch electrodes in a bar-and-stripe pattern. The bar-and-stripe pattern can improve touch signal levels for touch detection and improve uniformity of touch signal as objects move across the touch sensor panel/touch screen. Touch electrodes in a bar-and-stripe pattern can be formed from metal mesh in a single layer of metal mesh. In some examples, “stripes” can be formed from groups of touch electrode segments interconnected by bridges (formed in a second layer of metal mesh different from the first layer of metal mesh) in the active area of the touch screen (visible area of the display) and multiple stripes can be interconnected in the border area (outside of the visible area of the display) and/or in the active area to form a row touch electrode. In some examples, “bars” may also include bridges. To reduce the visibility of the metal mesh touch electrodes, the boundary between touch electrodes can be non-linear (with electrical discontinuities in the metal mesh in a non-linear pattern proceeding along the boundary) in some examples. In some examples, dummy cuts (electrical discontinuities in the metal mesh) can be made within an area of a touch electrode region (e.g., while maintaining the same electrical potential for the touch electrode region). 
       FIGS.  1 A- 1 E  illustrate example systems that can include a touch screen according to examples of the disclosure.  FIG.  1 A  illustrates an example mobile telephone  136  that includes a touch screen  124  according to examples of the disclosure.  FIG.  1 B  illustrates an example digital media player  140  that includes a touch screen  126  according to examples of the disclosure.  FIG.  1 C  illustrates an example personal computer  144  that includes a touch screen  128  according to examples of the disclosure.  FIG.  1 D  illustrates an example tablet computing device  148  that includes a touch screen  130  according to examples of the disclosure.  FIG.  1 E  illustrates an example wearable device  150  that includes a touch screen  132  and can be attached to a user using a strap  152  according to examples of the disclosure. It is understood that a touch screen can be implemented in other devices as well. 
     In some examples, touch screens  124 ,  126 ,  128 ,  130  and  132  can be based on self-capacitance. A self-capacitance based touch system can include a matrix of small, individual plates of conductive material or groups of individual plates of conductive material forming larger conductive regions that can be referred to as touch electrodes or as touch node electrodes (as described below with reference to  FIG.  4 B ). For example, a touch screen can include a plurality of individual touch electrodes, each touch electrode identifying or representing a unique location (e.g., a touch node) on the touch screen at which touch or proximity is to be sensed, and each touch node electrode being electrically isolated from the other touch node electrodes in the touch screen/panel. Such a touch screen can be referred to as a pixelated self-capacitance touch screen, though it is understood that in some examples, the touch node electrodes on the touch screen can be used to perform scans other than self-capacitance scans on the touch screen (e.g., mutual capacitance scans). During operation, a touch node electrode can be stimulated with an alternating current (AC) waveform, and the self-capacitance to ground of the touch node electrode can be measured. As an object approaches the touch node electrode, the self-capacitance to ground of the touch node electrode can change (e.g., increase). This change in the self-capacitance of the touch node electrode can be detected and measured by the touch sensing system to determine the positions of multiple objects when they touch, or come in proximity to, the touch screen. In some examples, the touch node electrodes of a self-capacitance based touch system can be formed from rows and columns of conductive material, and changes in the self-capacitance to ground of the rows and columns can be detected, similar to above. In some examples, a touch screen can be multi-touch, single touch, projection scan, full-imaging multi-touch, capacitive touch, etc. 
     In some examples, touch screens  124 ,  126 ,  128 ,  130  and  132  can be based on mutual capacitance. A mutual capacitance based touch system can include electrodes arranged as drive and sense lines that may cross over each other on different layers (in a double-sided configuration), or may be adjacent to each other on the same layer (e.g., as described below with reference to  FIG.  4 A ). The crossing or adjacent locations can form touch nodes. During operation, the drive line can be stimulated with an AC waveform and the mutual capacitance of the touch node can be measured. As an object approaches the touch node, the mutual capacitance of the touch node can change (e.g., decrease). This change in the mutual capacitance of the touch node can be detected and measured by the touch sensing system to determine the positions of multiple objects when they touch, or come in proximity to, the touch screen. As described herein, in some examples, a mutual capacitance based touch system can form touch nodes from a matrix of small, individual plates of conductive material. 
     In some examples, touch screens  124 ,  126 ,  128 ,  130  and  132  can be based on mutual capacitance and/or self-capacitance. The electrodes can be arranged as a matrix of small, individual plates of conductive material (e.g., as in touch node electrodes  408  in touch screen  402  in  FIG.  4 B ) or as drive lines and sense lines (e.g., as in row touch electrodes  404  and column touch electrodes  406  in touch screen  400  in  FIG.  4 A ), or in another pattern. The electrodes can be configurable for mutual capacitance or self-capacitance sensing or a combination of mutual and self-capacitance sensing. For example, in one mode of operation electrodes can be configured to sense mutual capacitance between electrodes and in a different mode of operation electrodes can be configured to sense self-capacitance of electrodes. In some examples, some of the electrodes can be configured to sense mutual capacitance therebetween and some of the electrodes can be configured to sense self-capacitance thereof. 
       FIG.  2    illustrates an example computing system including a touch screen according to examples of the disclosure. Computing system  200  can be included in, for example, a mobile phone, tablet, touchpad, portable or desktop computer, portable media player, wearable device or any mobile or non-mobile computing device that includes a touch screen or touch sensor panel. Computing system  200  can include a touch sensing system including one or more touch processors  202 , peripherals  204 , a touch controller  206 , and touch sensing circuitry (described in more detail below). Peripherals  204  can include, but are not limited to, random access memory (RAM) or other types of memory or storage, watchdog timers and the like. Touch controller  206  can include, but is not limited to, one or more sense channels  208 , channel scan logic  210  and driver logic  214 . Channel scan logic  210  can access RAM  212 , autonomously read data from the sense channels and provide control for the sense channels. In addition, channel scan logic  210  can control driver logic  214  to generate stimulation signals  216  at various frequencies and/or phases that can be selectively applied to drive regions of the touch sensing circuitry of touch screen  220 , as described in more detail below. In some examples, touch controller  206 , touch processor  202  and peripherals  204  can be integrated into a single application specific integrated circuit (ASIC), and in some examples can be integrated with touch screen  220  itself. 
     It should be apparent that the architecture shown in  FIG.  2    is only one example architecture of computing system  200 , and that the system could have more or fewer components than shown, or a different configuration of components. In some examples, computing system  200  can include an energy storage device (e.g., a battery) to provide a power supply and/or communication circuitry to provide for wired or wireless communication (e.g., cellular, Bluetooth, Wi-Fi, etc.). The various components shown in  FIG.  2    can be implemented in hardware, software, firmware or any combination thereof, including one or more signal processing and/or application specific integrated circuits. 
     Computing system  200  can include a host processor  228  for receiving outputs from touch processor  202  and performing actions based on the outputs. For example, host processor  228  can be connected to program storage  232  and a display controller/driver  234  (e.g., a Liquid-Crystal Display (LCD) driver). It is understood that although some examples of the disclosure may be described with reference to LCD displays, the scope of the disclosure is not so limited and can extend to other types of displays, such as Light-Emitting Diode (LED) displays, including Organic LED (OLED), Active-Matrix Organic LED (AMOLED) and Passive-Matrix Organic LED (PMOLED) displays. Display driver  234  can provide voltages on select (e.g., gate) lines to each pixel transistor and can provide data signals along data lines to these same transistors to control the pixel display image. 
     Host processor  228  can use display driver  234  to generate a display image on touch screen  220 , such as a display image of a user interface (UI), and can use touch processor  202  and touch controller  206  to detect a touch on or near touch screen  220 , such as a touch input to the displayed UI. The touch input can be used by computer programs stored in program storage  232  to perform actions that can include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device connected to the host device, answering a telephone call, placing a telephone call, terminating a telephone call, changing the volume or audio settings, storing information related to telephone communications such as addresses, frequently dialed numbers, received calls, missed calls, logging onto a computer or a computer network, permitting authorized individuals access to restricted areas of the computer or computer network, loading a user profile associated with a user&#39;s preferred arrangement of the computer desktop, permitting access to web content, launching a particular program, encrypting or decoding a message, and/or the like. Host processor  228  can also perform additional functions that may not be related to touch processing. 
     Note that one or more of the functions described herein, can be performed by firmware stored in memory (e.g., one of the peripherals  204  in  FIG.  2   ) and executed by touch processor  202 , or stored in program storage  232  and executed by host processor  228 . The firmware can also be stored and/or transported within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer-readable storage medium” can be any medium (excluding signals) that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. In some examples, RAM  212  or program storage  232  (or both) can be a non-transitory computer readable storage medium. One or both of RAM  212  and program storage  232  can have stored therein instructions, which when executed by touch processor  202  or host processor  228  or both, can cause the device including computing system  200  to perform one or more functions and methods of one or more examples of this disclosure. The computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
     The firmware can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     Touch screen  220  can be used to derive touch information at multiple discrete locations of the touch screen, referred to herein as touch nodes. Touch screen  220  can include touch sensing circuitry that can include a capacitive sensing medium having a plurality of drive lines  222  and a plurality of sense lines  223 . It should be noted that the term “lines” is sometimes used herein to mean simply conductive pathways, as one skilled in the art will readily understand, and is not limited to elements that are strictly linear, but includes pathways that change direction, and includes pathways of different size, shape, materials, etc. Drive lines  222  can be driven by stimulation signals  216  from driver logic  214  through a drive interface  224 , and resulting sense signals  217  generated in sense lines  223  can be transmitted through a sense interface  225  to sense channels  208  in touch controller  206 . In this way, drive lines and sense lines can be part of the touch sensing circuitry that can interact to form capacitive sensing nodes, which can be thought of as touch picture elements (touch pixels) and referred to herein as touch nodes, such as touch nodes  226  and  227 . This way of understanding can be particularly useful when touch screen  220  is viewed as capturing an “image” of touch (“touch image”). In other words, after touch controller  206  has determined whether a touch has been detected at each touch nodes in the touch screen, the pattern of touch nodes in the touch screen at which a touch occurred can be thought of as an “image” of touch (e.g., a pattern of fingers touching the touch screen). As used herein, an electrical component “coupled to” or “connected to” another electrical component encompasses a direct or indirect connection providing electrical path for communication or operation between the coupled components. Thus, for example, drive lines  222  may be directly connected to driver logic  214  or indirectly connected to drive logic  214  via drive interface  224  and sense lines  223  may be directly connected to sense channels  208  or indirectly connected to sense channels  208  via sense interface  225 . In either case an electrical path for driving and/or sensing the touch nodes can be provided. 
       FIG.  3 A  illustrates an example touch sensor circuit  300  corresponding to a self-capacitance measurement of a touch node electrode  302  and sensing circuit  314  according to examples of the disclosure. Touch node electrode  302  can correspond to a touch electrode  404  or  406  of touch screen  400  or a touch node electrode  408  of touch screen  402 . Touch node electrode  302  can have an inherent self-capacitance to ground associated with it, and also an additional self-capacitance to ground that is formed when an object, such as finger  305 , is in proximity to or touching the electrode. The total self-capacitance to ground of touch node electrode  302  can be illustrated as capacitance  304 . Touch node electrode  302  can be coupled to sensing circuit  314 . Sensing circuit  314  can include an operational amplifier  308 , feedback resistor  312  and feedback capacitor  310 , although other configurations can be employed. For example, feedback resistor  312  can be replaced by a switched capacitor resistor in order to minimize a parasitic capacitance effect that can be caused by a variable feedback resistor. Touch node electrode  302  can be coupled to the inverting input (−) of operational amplifier  308 . An AC voltage source  306  (V ac ) can be coupled to the non-inverting input (+) of operational amplifier  308 . Touch sensor circuit  300  can be configured to sense changes (e.g., increases) in the total self-capacitance  304  of the touch node electrode  302  induced by a finger or object either touching or in proximity to the touch sensor panel. Output  320  can be used by a processor to determine the presence of a proximity or touch event, or the output can be inputted into a discrete logic network to determine the presence of a proximity or touch event. 
       FIG.  3 B  illustrates an example touch sensor circuit  350  corresponding to a mutual-capacitance drive line  322  and sense line  326  and sensing circuit  314  according to examples of the disclosure. Drive line  322  can be stimulated by stimulation signal  306  (e.g., an AC voltage signal). Stimulation signal  306  can be capacitively coupled to sense line  326  through mutual capacitance  324  between drive line  322  and the sense line. When a finger or object  305  approaches the touch node created by the intersection of drive line  322  and sense line  326 , mutual capacitance  324  can change (e.g., decrease). This change in mutual capacitance  324  can be detected to indicate a touch or proximity event at the touch node, as described herein. The sense signal coupled onto sense line  326  can be received by sensing circuit  314 . Sensing circuit  314  can include operational amplifier  308  and at least one of a feedback resistor  312  and a feedback capacitor  310 .  FIG.  3 B  illustrates a general case in which both resistive and capacitive feedback elements are utilized. The sense signal (referred to as Vin) can be inputted into the inverting input of operational amplifier  308 , and the non-inverting input of the operational amplifier can be coupled to a reference voltage V ref . Operational amplifier  308  can drive its output to voltage V o  to keep V in  substantially equal to V ref , and can therefore maintain V in  constant or virtually grounded. A person of skill in the art would understand that in this context, equal can include deviations of up to 15%. Therefore, the gain of sensing circuit  314  can be mostly a function of the ratio of mutual capacitance  324  and the feedback impedance, comprised of resistor  312  and/or capacitor  310 . The output of sensing circuit  314  Vo can be filtered and heterodyned or homodyned by being fed into multiplier  328 , where Vo can be multiplied with local oscillator  330  to produce V detect . V detect  can be inputted into filter  332 . One skilled in the art will recognize that the placement of filter  332  can be varied; thus, the filter can be placed after multiplier  328 , as illustrated, or two filters can be employed: one before the multiplier and one after the multiplier. In some examples, there can be no filter at all. The direct current (DC) portion of V detect  can be used to determine if a touch or proximity event has occurred. Note that while  FIGS.  3 A- 3 B  indicate the demodulation at multiplier  328  occurs in the analog domain, output Vo may be digitized by an analog-to-digital converter (ADC), and blocks  328 ,  332  and  330  may be implemented in a digital fashion (e.g.,  328  can be a digital demodulator,  332  can be a digital filter, and  330  can be a digital NCO (Numerical Controlled Oscillator). 
     Referring back to  FIG.  2   , in some examples, touch screen  220  can be an integrated touch screen in which touch sensing circuit elements of the touch sensing system can be integrated into the display pixel stack-ups of a display. The circuit elements in touch screen  220  can include, for example, elements that can exist in LCD or other displays (LED display, OLED display, etc.), such as one or more pixel transistors (e.g., thin film transistors (TFTs)), gate lines, data lines, pixel electrodes and common electrodes. In a given display pixel, a voltage between a pixel electrode and a common electrode can control a luminance of the display pixel. The voltage on the pixel electrode can be supplied by a data line through a pixel transistor, which can be controlled by a gate line. It is noted that circuit elements are not limited to whole circuit components, such as a whole capacitor, a whole transistor, etc., but can include portions of circuitry, such as only one of the two plates of a parallel plate capacitor. 
       FIG.  4 A  illustrates touch screen  400  with touch electrodes  404  and  406  arranged in rows and columns according to examples of the disclosure. Specifically, touch screen  400  can include a plurality of touch electrodes  404  disposed as rows, and a plurality of touch electrodes  406  disposed as columns. Touch electrodes  404  and touch electrodes  406  can be on the same or different material layers on touch screen  400 , and can intersect with each other, as illustrated in  FIG.  4 A . In some examples, the electrodes can be formed on opposite sides of a transparent (partially or fully) substrate and from a transparent (partially or fully) semiconductor material, such as ITO, though other materials are possible. Electrodes displayed on layers on different sides of the substrate can be referred to herein as a double-sided sensor. In some examples, the touch electrodes can be formed on the same layer, and may be referred to herein as a single-sided sensor. In some examples, touch screen  400  can sense the self-capacitance of touch electrodes  404  and  406  to detect touch and/or proximity activity on touch screen  400 , and in some examples, touch screen  400  can sense the mutual capacitance between touch electrodes  404  and  406  to detect touch and/or proximity activity on touch screen  400 . 
       FIG.  4 B  illustrates touch screen  402  with touch node electrodes  408  arranged in a pixelated touch node electrode configuration according to examples of the disclosure. Specifically, touch screen  402  can include a plurality of individual touch node electrodes  408 , each touch node electrode identifying or representing a unique location on the touch screen at which touch or proximity (i.e., a touch or proximity event) is to be sensed, and each touch node electrode being electrically isolated from the other touch node electrodes in the touch screen/panel, as previously described. Touch node electrodes  408  can be on the same or different material layers on touch screen  400 . In some examples, touch screen  402  can sense the self-capacitance of touch node electrodes  408  to detect touch and/or proximity activity on touch screen  402 , and in some examples, touch screen  402  can sense the mutual capacitance between touch node electrodes  408  to detect touch and/or proximity activity on touch screen  402 . 
     As described herein, in some examples, touch electrodes of the touch screen can be formed from a metal mesh.  FIG.  5 A  illustrates an example touch screen stack-up including a metal mesh layer according to examples of the disclosure. Touch screen  500  can include a substrate  509  (e.g., a printed circuit board) upon which display LEDs  508  can be mounted. In some examples, the LEDs  508  can be partially or fully embedded in substrate  509  (e.g., the components can be placed in depressions in the substrate). Substrate  509  can include routing traces in one or more layers (e.g., represented by metal layer  510  in  FIG.  5 A ) to route the LEDs to display driving circuitry (e.g., display driver  234 ). The stack-up of touch screen  500  can also include one or more passivation layers deposited over the LEDs  508 . For example, the stack-up of touch screen  500  illustrated in  FIG.  5    can include a passivation layer  507  (e.g., transparent epoxy) and passivation layer  517 . Passivation layers  507  and  517  can planarize the surface for respective metal mesh layers. Additionally, the passivation layers can provide electrical isolation (e.g., between metal mesh layers and between the LEDs and a metal mesh layer. Metal mesh layer  516  (e.g., copper, silver, etc.) can be deposited on the planarized surface of the passivation layer  517  over the display LEDs  508 , and metal mesh layer  506  (e.g., copper, silver, etc.) can be deposited on the planarized surface of passivation layer  507 . In some examples, the passivation layer  517  can include material to encapsulate the LEDs to protect them from corrosion or other environmental exposure. Metal mesh layer  506  and/or metal mesh layer  516  can include a pattern of conductor material in a mesh pattern described below. In some examples, metal mesh layer  506  and metal mesh layer  516  can be coupled by one or more vias. Additionally, although not shown in  FIG.  5 A , a border region around the display active area can include metallization (or other conductive material) that may or may not be a metal mesh pattern. In some examples, metal mesh is formed of a non-transparent material but the metal mesh wires are sufficiently thin and sparse to appear transparent to the human eye. The touch electrodes (and some routing) as described herein can be formed in the metal mesh layer(s) from portions of the metal mesh. In some examples, polarizer  504  can be disposed above the metal mesh layer  506  (optionally with another planarization layer disposed over the metal mesh layer  506 ). Cover glass (or front crystal)  502  can be disposed over polarizer  504  and form the outer surface of touch screen  500 . It is understood that although two metal mesh layers (and two corresponding planarization layers) are illustrated, in some examples more or fewer metal mesh layers (and corresponding planarization layers) can be implemented. Additionally, it is understood that LEDs  508 , substrate  509 , metal layer  510 , and/or passivation layer  517  can be replaced by a thin-film transistor (TFT) LCD display (or other types of displays), in some examples. Additionally, it is understood that polarizer  504  can include one or more transparent layers including a polarizer, adhesive layers (e.g., optically clear adhesive) and protective layers. 
       FIG.  5 B  illustrates a top view of a portion of touch screen  500  in a diamond pattern according to examples of the disclosure. The top view shows metal mesh  540  (e.g., a portion of metal mesh layer  506 ) together with LEDs  508  of touch screen  500 . The LEDs can be arranged in groups of three proximate LEDs, including a red LED (e.g., red LED  544 ), a green LED (e.g., green LED  546 ), and a blue LED (e.g., blue LED  548 ), to form standard red-green-blue (RGB) display pixels. Although primarily described herein in terms of an RGB display pixel, it is understood that other touch pixels are possible with different numbers of LEDs and/or different color LEDs. The metal mesh can be formed of conductors (e.g., metal mesh wires formed from conductive materials such as copper, silver, etc.) disposed in a pattern to allow light to pass (at least vertically) through the gaps in the mesh (e.g., the LEDs  508  can be disposed in the LED layer opposite openings in the metal mesh disposed in the metal mesh layer(s)  506  and/or  516 ). In other words, the conductors of metal mesh layer can be patterned so that conceptually flattening the metal mesh layer(s) and LEDs into the same layer, the conductors and the LEDs do not overlap. In some examples, the metal mesh wires in the metal mesh layer may overlap (at least partially) some of the LEDs  508 , but may be thin enough or sparse enough to not obstruct a human&#39;s view of the LEDs. The metal mesh  540  can be formed in a diamond pattern around LEDs arranged in a diamond configuration. The pattern of LEDs forming the display pixels can be repeated across the touch screen to form the display. During fabrication, the metal mesh pattern can repeat across the touch screen to form a touch screen with uniform optical characteristics. It should be understood that the arrangement of LEDs and the corresponding metal mesh are merely an example, and other arrangements of LEDs and corresponding metal mesh patterns are possible. For example, the metal mesh can, in some examples, form a rectangular shape (or other suitable shape including polygonal shapes, etc.) around rectangular-shaped LEDs. 
     As described herein, the touch electrodes and/or routing can be formed from the metal mesh. To form the electrically isolated touch electrodes or electrically isolated groups of touch electrodes (e.g., groups of touch electrodes forming row electrodes or column electrodes), the metal mesh can be cut (e.g., chemically or laser etched, among other possibilities) to form a boundary between two adjacent touch electrodes, between two adjacent routing traces or between a routing trace and adjacent touch electrode. The cut in the metal mesh can electrically isolate the metal mesh forming a first touch electrode (or first group of touch electrodes) from the metal mesh forming a second touch electrode (or second group of touch electrodes). Similarly, cuts to the metal mesh can be made to electrically isolate the metal mesh forming a first touch electrode from a first routing trace or to electrically isolate the first routing trace from a second routing trace. 
     As described herein, in some examples, touch electrodes can be arranged in rows and columns formed in a first layer. In some examples, the touch electrodes can be arranged in a bar-and-stripe pattern. The column touch electrodes illustrated in  FIGS.  6 A- 7    can be referred to as “bars” and the row touch electrodes can be formed from interconnected touch electrode segments that can be referred to as “stripes” (e.g., interconnected via bridges).  FIGS.  6 A- 6 E  illustrate various example unit cells that can be repeated across a touch sensor panel to form a bar-and-stripe pattern according to examples of the disclosure.  FIG.  7    illustrates an example of a touch sensor panel formed of nine unit cells (3×3) corresponding to the example unit cell of  FIG.  6 B . 
       FIG.  6 A  illustrates an example unit cell corresponding to a touch node according to examples of the disclosure. The unit cell  600  can include a portion of a column touch electrode  602  (corresponding to a “bar”) and a portion of a row electrode formed from touch electrode segments  604 A- 604 F (corresponding to “stripes”). A mutual capacitance between the column touch electrode and the row touch electrode can, which can change due to the proximity of an object (e.g., a finger) at a touch node corresponding to the unit cell. The column touch electrode  602  can correspond to a contiguous, electrically connected region, including regions around the touch electrode segments  604 A- 604 F. The touch electrode segments  604 A- 604 F of the row electrode can be electrically connected using one or more bridges  606 A- 606 G that bridge across the neck regions  608 A- 608 D of the column touch electrode  602  between the touch electrode segments  604 A- 604 F. In some examples, one bridge can be used to interconnect two touch electrode segments (e.g., bridges  606 A- 606 D). In some examples, more than one bridge can be used to interconnect two touch electrode segments (e.g., bridges  606 A and  606 E, bridges  606 B and  606 F, etc.). Bridge-connected touch electrodes segments  604 A- 604 C (e.g., corresponding to a first “stripe” in the bar-and-stripe pattern) and bridge-connected touch electrode segments  604 D- 604 F (e.g., corresponding to a second “stripe” in the bar-and-stripe pattern) can be electrically connected outside of the unit cell area (e.g., as illustrated in  FIG.  7   ). In some examples, the first and second stripes can be electrically connected to one another within the unit cell area (e.g., with bridges). In some examples, bridges  606 A- 606 G may be achieved using wire bonds or other conductors formed without using a metal mesh layer. In some examples, bridges  606 A- 606 G may be formed using a metal mesh layer (e.g., metal mesh layer  516 ) different than the metal mesh layer used to form column touch electrode  602  and touch electrode segments  604 A- 604 F (e.g., metal mesh layer  506 ). The connection between the metal mesh layers can also include a via (or other interconnection), in some examples, to make connections between the first metal mesh layer and the second metal mesh layer. It is understood that that bridges  606 A- 606 G may include multiple metal mesh wires (e.g., increasing the width of the bridge) to meet the resistance requirements for the rows touch electrodes. 
     The distribution of the touch electrode segments within the unit cell can improve the touch signal levels (and therefore the signal-to-noise ratio (SNR) for touch sensing) because mutual capacitance in a single-layer touch sensor panel can be a function of the distance between the touch electrodes that are driven and sensed. For example, the mutual capacitances can be greater along the boundaries between a touch electrode that is driven and a touch electrode that is sensed as compared with the center of the two touch electrodes. Thus, by dividing the row electrode into multiple stripes (thereby reducing the maximum spacing between a region of the drive electrode and a region of a sense electrode in the unit cell), the signal measured at the unit cell can be increased relative to other touch electrode patterns (e.g., a diamond touch electrode pattern, etc.). The impact of the distributed bar-and-stripe pattern on the mutual capacitance can provide increased modulation between finger and the sensor. Additionally, the distribution of the touch electrode segments can provide improved linearity of the touch signal detected as an object moves across the touch sensor panel (e.g., more uniform signal measured by an object, independent on the location of the object on the touch sensor panel). Improved linearity can provide various benefits of improved touch performance that include more precise and accurate touch location detection, reduced wobble, etc. 
       FIG.  6 B  illustrates an example unit cell corresponding to a touch node according to examples of the disclosure. The unit cell  620  can include a portion of a column touch electrode and a portion of a row electrode formed from touch electrode segments as described with reference to  FIG.  6 A , including column touch electrode  602 , touch electrode segments (e.g., such as representative touch electrode segment  604 ), and interconnections (e.g., such as bridge  606 ) over neck regions between touch electrode segments. For brevity, the details of these features are not repeated again here (and for ease of illustration only one bridge is illustrated between segments). Unlike  FIG.  6 A , unit cell  620  can include buffering regions between portions of column touch electrode  602  and touch electrode segments. The buffer regions can be conductive material that is floating (or grounded or driven with a potential, in some examples). The buffer region can reduce the baseline mutual capacitance of the touch node by increasing the distance between the drive and sense regions. For example, touch electrode segment  604  in  FIG.  6 B  can be separated on a first boundary with column touch electrode  602  by buffer region  622 A and can be separated on a second boundary with column electrode  602  by buffer region  622 B. The remaining touch electrode segments illustrated in  FIG.  6 B  can include similar buffer regions between the column touch electrode  602  and the touch electrode segments. Although  FIG.  6 B  illustrates buffer regions on two sides of each of the touch electrode segments, it is understood that in some examples, the buffering can be on fewer sides (one or no sides) or more sides (three or four sides) of the touch electrode segments. Increasing the separation (e.g., surface area and/or width) can further reduce the baseline capacitance, whereas decreasing the separation can increase the baseline capacitance. In some examples, as illustrated in  FIG.  6 B , the neck region can be free of buffer regions to reduce the impedance of the column touch electrode  602 . Additionally, although buffer regions are shown as continuous along a respective boundary of a touch electrode segment, that the buffer region (e.g., buffer region  622 A) can be discontinuous so as to be present in one or more segments along a portion of the boundary. Additionally, although similar buffer regions are shown on all touch electrode segments in unit cell  620 , it is understood that different touch electrode segments in a unit cell can have different numbers of buffer regions or buffer regions with different properties (dimensions, distributions, etc.). 
       FIG.  6 C  illustrates an example unit cell corresponding to a touch node according to examples of the disclosure. The unit cell  630  can include a portion of a column touch electrode and a portion of a row electrode formed from touch electrode segments as described with reference to  FIG.  6 A , including column touch electrode  602 , touch electrode segments (e.g., such as representative touch electrode segment  604 ), and interconnections (e.g., such as bridge  606 ) over neck regions between touch electrode segments. For brevity, the details of these features are not repeated here. Unlike  FIG.  6 A , unit cell  630  can include fewer touch electrode segments and fewer interconnections between touch electrode segments. For example,  FIG.  6 C  includes four touch electrode segments, rather than the six touch electrode segments of  FIG.  6 A . Likewise,  FIG.  6 C  includes two interconnections, rather than the four interconnections of  FIG.  6 A . Reducing the number of interconnections can reduce the baseline mutual capacitance of the touch node because interconnections of bridges  606  can result in increased mutual capacitance due to the proximity between the drive and sense regions at these interconnections. Additionally, reducing the number of interconnections can reduce the resistance of the row touch electrodes. Although  FIG.  6 C  illustrates two interconnections between four touch electrode segments, it should be understood that fewer or more interconnections and touch electrode segments can be employed. In some examples, to compensate for the reduced number of neck portions in  FIG.  6 C  compared with  FIG.  6 A  (e.g., connecting different portions of column touch electrode  602 ), the width of the neck portion can be increased in  FIG.  6 C  relative to  FIG.  6 A  to avoid increasing the resistance of the column touch electrode. 
       FIG.  6 D  illustrates an example unit cell corresponding to a touch node according to examples of the disclosure. The unit cell  640  can include a portion of a column touch electrode and a portion of a row electrode formed from touch electrode segments as described with reference to  FIG.  6 A , including column touch electrode  602 , touch electrode segments (e.g., such as representative touch electrode segment  604 ), and interconnections (e.g., such as bridge  606 ) over neck regions  608  between touch electrode segments. For brevity, the details of these features are not repeated here. Unlike  FIG.  6 A , unit cell  640  can include a tapered neck region between touch electrode segments. Neck region  608  illustrated in  FIG.  6 D  can taper from a first width W 1  away from the interconnection of bridge  606  to a second width W 2  at (or closer to) the location of the interconnection of bridge  606 . The second width W 2  can be less than the first width W 1 . As a result, the interconnection of bridge  606  can be shorted, which can reduce the baseline mutual capacitance for the touch node. However, by tapering neck region  608 , the resistance of column electrode  602  can be lower than in the configuration of  FIG.  6 D  compared with narrowing the entire neck region to width W 2 . The tapering forming a triangle shape as illustrated in  FIG.  6 D  is an example of tapering, but any linear, non-linear or other narrowing of the neck region can be used to shrink the size of the interconnect. The neck region between other touch electrode segments can be tapered (or not) using the same (or different) tapers. 
       FIG.  6 E  illustrates an example unit cell corresponding to a touch node according to examples of the disclosure. The unit cell  650  can include a portion of a column touch electrode and a portion of a row electrode. However, unlike the description of  FIG.  6 A , the column touch electrode can be formed from touch electrode segments  602 A- 602 C that can be interconnected by bridges  610  in the neck region  608 , and the row touch electrode can be formed from stripes  604 A- 604 B, each of which can be contiguous (e.g., and may be interconnected in the border area). In some examples, the bridges  610  can be implemented may be achieved using wire bonds or other conductors formed without using a metal mesh layer. In some examples, bridges  610  may be formed using a metal mesh layer (e.g., metal mesh layer  516 ) different than the metal mesh layer used to form the column touch electrode segments  602 A- 602 C and row touch electrode stripes  604 A- 604 B (e.g., metal mesh layer  506 ). The connection between the metal mesh layers can also include a via (or other interconnection), in some examples, to make connections between the first metal mesh layer and the second metal mesh layer. It is understood that that bridges  610  may include multiple metal mesh wires (e.g., increasing the width of the bridge) to meet the resistance requirements for the column touch electrodes. It should be understood that other features illustrated in  FIGS.  6 A- 6 D  for row touch electrodes formed from touch electrode segments can be implemented for column touch electrodes formed from touch electrode segments (e.g., multiple bridges, tapered neck regions, etc.) 
     In some examples, the neck region  608  can include bridges for both column touch electrodes and row touch electrodes. Some of the bridges can be used to electrically connect touch electrode segments (e.g., as described with reference to  FIG.  6 A  and  FIG.  6 E  for row and column touch electrodes, respectively), and some bridges can be used to electrically connect regions of column touch electrodes or row touch electrodes to further reduce the impedance of the column touch electrodes or row touch electrodes. For example, unit cell  600  can be modified to include a bridge similar to bridge  610  of  FIG.  6 E , but electrically connecting regions of column touch electrode  602  to further reduce impedance of column touch electrode  602  (rather than to bridge column electrode segments as in  FIG.  6 E , because column touch electrode  602  in  FIG.  6 A  can be contiguous). In a similar manner, unit cell  650  can be modified to include a bridge similar to bridges in  FIG.  6 A  to reduce impedance of row touch electrodes. In some examples, the bridges (in a second metal mesh layer) between different regions of a contiguous electrode (e.g., in the first metal mesh layer) can be restricted to the neck region  608  where the narrowness of the touch electrode can be an impedance bottleneck. In some examples, bridges connecting different regions of a contiguous electrode can extend beyond neck region  608 . 
     It should be understood that although unit cells  600 ,  620 ,  630 ,  640  and  650  in  FIGS.  6 A- 6 E  illustrate two stripes in the unit cell (two rows of interconnected touch electrode segments), that the number of stripes can be greater than two (e.g., three, four, etc.) or less than two (e.g., one) in some examples. It should be understood that unit cells  600 ,  620 ,  630 ,  640  and  650  are example unit cells. The number and dimensions of touch electrode segments, the number and dimensions of interconnections between touch electrode segments (and between portions of a column touch electrodes), and the thickness and dimensions of the neck region can be varied according to design considerations, including trading off the impedance of the row and/or column touch electrodes and the baseline capacitance for the unit cell, including an amount of desired for touch signal, and including the linearity of the touch signals across the touch sensor panel. Although described separately above, one or more of the features illustrated in  FIGS.  6 A- 6 E  can be combined in some examples. For example, the multiple bridges of  FIG.  6 A , the buffer regions of  FIG.  6 B , the reduced number of interconnections of  FIG.  6 C , and/or the shape (dimensions) of the neck region of  FIG.  6 D . It should be understood that although column touch electrodes are illustrated as contiguous and row touch electrodes are illustrated as formed of touch electrode segments, in some examples, row touch electrodes can be contiguous and column touch electrodes can be formed of touch electrode segments. It should be understood that although unit cells  600 ,  620 ,  630 ,  640  and  650  have uniform widths, that the width of “strips” or “bars” in a unit cell may be non-uniform. 
       FIG.  7    illustrates an example of a touch sensor panel formed from unit cells according to examples of the disclosure. For example, touch sensor panel  700  can include nine unit cells corresponding to unit cell  710  (3×3 touch nodes) corresponding to the example unit cell of  FIG.  6 B  (e.g., corresponding to unit cell  620 ). For brevity, the details of the unit cell described with reference to  FIG.  6 B  are not repeated. As illustrated in  FIG.  7   , touch sensor panel  700  can include three column touch electrodes  702 A- 702 C (“bars”) that can be driven during touch sensing operation (e.g., by drive signals provided by routing traces labeled “DRV_N−1”, “DRV_N” and “DRV_N+1”). Touch sensor panel  700  can also include three row touch electrodes. Each of the row touch electrodes illustrated in  FIG.  7    can include two “stripes” formed of touch electrode segments  704 . The touch electrode segments  704  for each “stripe” can be interconnected within the touch sensor panel active area (e.g., in the visible area of the display in a touch screen) by bridges  706  (e.g., metal mesh). Although one bridge  706  between touch electrodes segments is illustrated in  FIG.  7   , it is understood that additional bridges can be used to improve electrostatic discharge protection, improve mechanical and/or electrical reliability of the connection and/or reduce impedance of the row touch electrode, Additionally, although not shown in  FIG.  7   , additional bridges (e.g., as illustrated in and described with reference to  FIG.  6 E ) can be used to provide the same or similar benefits for column touch electrodes. The two “stripes” of a row electrode can be connected in a border area (e.g., outside of the touch sensor panel active area/outside the visible area of the display) by conductive traces (e.g., metal mesh or otherwise). Each row electrode can be sensed during touch sensing operation (e.g., by sense channels coupled to routing traces labeled “SNS_N−1”, “SNS_N”, “SNS_N+1”). The adjacencies of a respective column touch electrode and a respective row touch electrode can form a respective touch node/unit cell of touch sensor panel  700 . 
     Although the example unit cell of  FIG.  6 B  is illustrated in unit cell  710  (e.g., including a buffer region), it should be understood that alternative unit cells can be used, such as the unit cells of  FIGS.  6 A,  6 C,  6 D,  6 E  or some combination of some or all of the unit cells of  FIGS.  6 A- 6 E  (or other unit cells according to the features described herein). Additionally, although a 3×3 grouping of unit cells is illustrated, it is understood that the panel can be of a smaller or larger size (e.g., 2×2, 4×4, 5×5, 10×10, 16×16, etc.) Additionally, although  FIG.  7    illustrates column touch electrodes that are driven and rows touch electrodes that are sensed, in some examples, the row touch electrodes can be driven and the column touch electrodes can be sensed. 
     Although  FIGS.  6 A- 7    illustrate rectangular electrodes for row and column touch electrodes with linear boundaries, it should be understood that due to the pattern of metal mesh and to reduce the visibility of the metal mesh, the true shape of touch electrodes and their boundaries may not be rectangular.  FIG.  8    illustrates a metal mesh corresponding to a portion of unit cell of  FIG.  6 A  according to examples of the disclosure. Metal mesh  800  can correspond, for example, to half of unit cell  600  of  FIG.  6 A . Metal  800  mesh can include a first metal mesh portion  802  corresponding to column touch electrode  602  and second metal mesh portions  804 A- 804 C corresponding to touch electrode segments  604 A- 604 C. Due to the diamond pattern (with 45 degree angles) and to reduce the visibility of the boundaries of the touch electrodes, the first and second metal mesh portions can be non-linear along the boundaries. In some examples, the boundaries between the touch electrodes can be a zig-zag or wave-like pattern. For example, as illustrated in  FIG.  8   , the boundary between first metal mesh portion  802  and second metal mesh portion  804 B can have a zig-zag pattern where the length of segments  812  and  814  can each be a length of three metal mesh wires. A similar pattern can be implemented for the other boundaries illustrated in  FIG.  8    (with slight variations at the corners for continuity according to the geometry of the pattern). It should be understood that the length of segments  812  and  814  are exemplary, and other lengths are possible. Additionally, the lengths can be different at different points along a boundary or different between two different boundaries. In some examples, rather than defining the pattern by the lengths of segments such as segments  812  and  814 , the zig-zag pattern can be defined by other parameters. 
     The touch electrodes (and buffer regions) can be formed from metal mesh in the metal mesh layer (e.g., corresponding to metal mesh layer  506 ) by cuts or electrical discontinuities in the metal mesh wires between the touch electrodes (and/or buffer regions). In some examples, the cuts or electrical discontinuities can be formed at midpoints of metal mesh wires (or otherwise dividing one or more metal mesh wires), rather than having cuts or electrical discontinuities at vertices of two metal mesh wires in the metal mesh pattern. 
     In some examples, dummy cuts can further reduce visibility of the metal mesh boundary cuts. A dummy cut can interrupt one electrical path between two portions of the metal mesh (on either side of the dummy cut), without electrically isolating the metal mesh due to one or more other electrical paths between two portions of the metal mesh (on either side of the dummy cut). In other words, the portions of the metal mesh can remain at substantially the same electrical potential despite the internal cuts because the portions of the metal mesh are electrically connected. For example, dummy cuts can be made within the first metal mesh portion  802  and/or in the second metal mesh portions  804 A- 804 C that form physical separations in the metal mesh without electrically separating the metal mesh in each respective portion. In some examples, the dummy cuts can form a pattern that can be repeated across each of the touch electrodes. For example, a dummy cut unit (e.g., a pattern of discontinuities) can be defined, and the dummy cut unit can be repeated across the touch screen to form the dummy cuts. In some examples, dummy cuts can also be implemented for buffer regions (e.g., buffer region  622 A- 622 B) between the column touch electrodes and touch electrode segments. 
     In some examples, dummy cuts in the first metal mesh portion  802  can be restricted to certain regions. For example, dummy cuts may be excluded, or limited, in neck regions  808  of the first metal mesh portion  802 . Excluding (or limiting) dummy cuts in the neck regions  808  can be beneficial in some instances to reduce the impedance of the column touch sensor (due to the narrow width of the metal mesh in the neck regions). 
     Although  FIGS.  6 A- 8    illustrate column touch electrodes and row touch electrodes disposed in a first metal mesh layer (e.g., corresponding to metal mesh layer  506 ) that may include interconnections in a second metal mesh layer (e.g., corresponding to metal mesh layer  516 ), it should be understood that in some examples, the column touch electrodes can be disposed in one layer and the row touch electrodes can be disposed in another layer (e.g., in a double-sided touch senor configuration as illustrated in  FIG.  4 A ). 
     Therefore, according to the above, some examples of the disclosure are directed to a touch screen comprising: a display having an active area; a plurality of touch electrodes formed of metal mesh disposed in a first metal mesh layer disposed over the active area of the display; and a plurality of bridges formed at least partially in a second metal mesh layer different from the first metal mesh layer. The plurality of touch electrodes can include one or more contiguous column touch electrodes and can include one or more row touch electrodes formed from a plurality of touch electrode segments. A bridge of the plurality of bridges electrically can couple two of the touch electrode segments along a first axis parallel to the one or more row touch electrodes. Additionally or alternatively to the examples disclosed above, in some examples, one of the one or more row touch electrodes can include a two dimensional array of touch electrode segments of the plurality of touch electrode segments. A first group of the touch electrode segments disposed along the first axis can be electrically coupled by one or more first bridges of the plurality of bridges, and a second group of the touch electrode segments, different from and disposed parallel to the first group of the touch electrode segments, can be electrically coupled by one or more second bridges of the plurality of bridges. Additionally or alternatively to the examples disclosed above, in some examples, the first group of the touch electrodes segments and the second group of the touch electrode segments can be electrically coupled via a conductor disposed in a border region around the active area of the display. Additionally or alternatively to the examples disclosed above, in some examples, a respective touch node of the touch screen corresponding to adjacency of one of the one or more column touch electrodes and the one of the one or more row touch electrodes can include three touch electrode segments of the first group that can be electrically coupled by two bridges of the plurality of bridges and the second group can include three touch electrode segments of the second group that can be electrically coupled by another two bridges of the plurality of bridges. Additionally or alternatively to the examples disclosed above, in some examples, a respective touch node of the touch screen corresponding to adjacency of one of the one or more column touch electrodes and the one of the one or more row touch electrodes can include two touch electrode segments of the first group that can be electrically coupled by a first bridge of the plurality of bridges and the second group can include two touch electrode segments of the second group that can be electrically coupled by a second bridge of the plurality of bridges. Additionally or alternatively to the examples disclosed above, in some examples, the touch screen can further comprise: one or more buffer electrodes disposed between one or more portions of the one or more column touch electrode and one or more portions of the plurality of touch electrode segments. The one or more buffer electrodes can be floating or grounded or driven with a potential. Additionally or alternatively to the examples disclosed above, in some examples, a neck region between two of the plurality of touch electrode segments tapers from a first width to a second width less than the first width. A length of the bridge of the plurality of bridges that electrically couples the two of the touch electrode segments across the neck region can be greater than or equal to the second width and less than the length of the first width. Additionally or alternatively to the examples disclosed above, in some examples, electrical discontinuities in the metal mesh disposed in the first metal mesh layer can form boundaries between one of the column touch electrodes and one or more touch electrode segments of the plurality of touch electrode segments. The boundaries can be in a zig-zag pattern. Additionally or alternatively to the examples disclosed above, in some examples, the metal mesh of one of the column touch electrodes can be at a same electrical potential (or substantially the same electrical potential), and the metal mesh of the one of the column touch electrodes can include electrical discontinuities (dummy cuts) internal to an area of the one of the column touch electrodes. Additionally or alternatively to the examples disclosed above, in some examples, the metal mesh of one of the plurality of touch electrode segments can be at a same electrical potential (or substantially the same electrical potential), and the metal mesh of the one of the plurality of touch electrode segments can include electrical discontinuities (dummy cuts) internal to an area of the one of the plurality of touch electrode segments. Additionally or alternatively to the examples disclosed above, in some examples, a pattern of electrical discontinuities (dummy cuts) internal to an area of one of the plurality of touch electrodes can repeat across the area of the one of the plurality of touch electrodes. Additionally or alternatively to the examples disclosed above, in some examples, the metal mesh of one of the column touch electrodes can be at a same electrical potential (or substantially the same electrical potential), and a first region of the metal mesh of the one of the column touch electrodes can include electrical discontinuities (dummy cuts) internal to an area of the one of the column touch electrodes and a second region of the metal mesh of the one of the column touch electrodes may not include electrical discontinuities (dummy cuts) internal to the area of the one of the column touch electrodes. The second region can correspond to a neck region between two of the plurality of touch electrode segments. 
     Some examples of the disclosure are directed to a touch screen comprising: a display having an active area; a plurality of column touch electrodes formed of metal mesh disposed in a first metal mesh layer; and a plurality of row touch electrodes formed of metal mesh disposed in a second metal mesh layer different from the first metal mesh layer. A row touch electrode of the plurality of row touch electrodes (or all of the row touch electrodes) can include at least two electrodes disposed over the active area of the display that can be electrically coupled via a conductor disposed in a border region around the active area of the display. 
     Some examples of the disclosure are directed to a touch-sensitive device. The touch-sensitive device can include an energy storage device (e.g., a battery) and/or (wired or wireless) communication circuitry. The touch-sensitive device can include a touch controller and a display controller. The touch-sensitive device can also include a touch screen. The touch screen can comprise: a display having an active area; a plurality of touch electrodes formed of metal mesh disposed in a first metal mesh layer disposed over the active area of the display; and a plurality of bridges formed at least partially in a second metal mesh layer different from the first metal mesh layer. The plurality of touch electrodes can include one or more contiguous column touch electrodes and can include one or more row touch electrodes formed from a plurality of touch electrode segments. A bridge of the plurality of bridges electrically can couple two of the touch electrode segments along a first axis parallel to the one or more row touch electrodes. Additionally or alternatively to the examples disclosed above, in some examples, one of the one or more row touch electrodes can include a two dimensional array of touch electrode segments of the plurality of touch electrode segments. A first group of the touch electrode segments disposed along the first axis can be electrically coupled by one or more first bridges of the plurality of bridges, and a second group of the touch electrode segments, different from and disposed parallel to the first group of the touch electrode segments, can be electrically coupled by one or more second bridges of the plurality of bridges. Additionally or alternatively to the examples disclosed above, in some examples, the first group of the touch electrodes segments and the second group of the touch electrode segments can be electrically coupled via a conductor disposed in a border region around the active area of the display. Additionally or alternatively to the examples disclosed above, in some examples, a respective touch node of the touch screen corresponding to adjacency of one of the one or more column touch electrodes and the one of the one or more row touch electrodes can include three touch electrode segments of the first group that can be electrically coupled by two bridges of the plurality of bridges and the second group can include three touch electrode segments of the second group that can be electrically coupled by another two bridges of the plurality of bridges. Additionally or alternatively to the examples disclosed above, in some examples, a respective touch node of the touch screen corresponding to adjacency of one of the one or more column touch electrodes and the one of the one or more row touch electrodes can include two touch electrode segments of the first group that can be electrically coupled by a first bridge of the plurality of bridges and the second group can include two touch electrode segments of the second group that can be electrically coupled by a second bridge of the plurality of bridges. Additionally or alternatively to the examples disclosed above, in some examples, the touch screen can further comprise: one or more buffer electrodes disposed between one or more portions of the one or more column touch electrode and one or more portions of the plurality of touch electrode segments. The one or more buffer electrodes can be floating or grounded or driven with a potential. Additionally or alternatively to the examples disclosed above, in some examples, a neck region between two of the plurality of touch electrode segments tapers from a first width to a second width less than the first width. A length of the bridge of the plurality of bridges that electrically couples the two of the touch electrode segments across the neck region can be greater than or equal to the second width and less than the length of the first width. Additionally or alternatively to the examples disclosed above, in some examples, electrical discontinuities in the metal mesh disposed in the first metal mesh layer can form boundaries between one of the column touch electrodes and one or more touch electrode segments of the plurality of touch electrode segments. The boundaries can be in a zig-zag pattern. Additionally or alternatively to the examples disclosed above, in some examples, the metal mesh of one of the column touch electrodes can be at a same electrical potential (or substantially the same electrical potential), and the metal mesh of the one of the column touch electrodes can include electrical discontinuities (dummy cuts) internal to an area of the one of the column touch electrodes. Additionally or alternatively to the examples disclosed above, in some examples, the metal mesh of one of the plurality of touch electrode segments can be at a same electrical potential (or substantially the same electrical potential), and the metal mesh of the one of the plurality of touch electrode segments can include electrical discontinuities (dummy cuts) internal to an area of the one of the plurality of touch electrode segments. Additionally or alternatively to the examples disclosed above, in some examples, a pattern of electrical discontinuities (dummy cuts) internal to an area of one of the plurality of touch electrodes can repeat across the area of the one of the plurality of touch electrodes. Additionally or alternatively to the examples disclosed above, in some examples, the metal mesh of one of the column touch electrodes can be at a same electrical potential (or substantially the same electrical potential), and a first region of the metal mesh of the one of the column touch electrodes can include electrical discontinuities (dummy cuts) internal to an area of the one of the column touch electrodes and a second region of the metal mesh of the one of the column touch electrodes may not include electrical discontinuities (dummy cuts) internal to the area of the one of the column touch electrodes. The second region can correspond to a neck region between two of the plurality of touch electrode segments. 
     Although examples of this disclosure have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of examples of this disclosure as defined by the appended claims.

Metadata:
Filing Date: 20230113
Publication Date: 20240723
Grant Date: 20240723
Priority Date: 20200203
Inventors: BLONDIN, Christophe
ZHOU, XIAOQI
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04112", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/04166", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04112", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04112", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0448", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2203/04112", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/04166", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 77062511