PATENT DOCUMENT

Publication Number: US-11054948-B2
Application Number: US-201916585957-A
Country: US
Kind Code: B2

Title: Light transmissivity-controlled touch sensor panel design

Abstract:
A touch sensor panel is disclosed. In some examples, the touch sensor panel includes a substrate including a first side and a second side, a passivation layer, a first plurality of touch electrodes formed on the first side of the substrate, and a second plurality of touch electrodes formed on the second side of the substrate. In some examples, a component of the touch sensor panel, other than the first plurality of touch electrodes and the second plurality of touch electrodes, is configured to prevent light configured to activate the passivation layer during fabrication of the touch sensor panel from being transmitted from the first side of the substrate to the second side of the substrate.

Claims:
The invention claimed is: 
     
       1. A touch sensor panel comprising:
 a substrate including a first side and a second side; 
 a passivation layer; 
 a first plurality of touch electrodes formed on the first side of the substrate; and 
 a second plurality of touch electrodes formed on the second side of the substrate, 
 wherein a component of the touch sensor panel, other than the first plurality of touch electrodes and the second plurality of touch electrodes, is configured to prevent light configured to activate the passivation layer during fabrication of the touch sensor panel from being transmitted from the first side of the substrate to the second side of the substrate, the component configured with a transmissivity less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. 
 
     
     
       2. The touch sensor panel of  claim 1 , wherein:
 the component is the substrate. 
 
     
     
       3. The touch sensor panel of  claim 1 , wherein:
 the component is an attenuation mask formed in a same material layer as the first plurality of touch electrodes. 
 
     
     
       4. The touch sensor panel of  claim 3 , wherein the attenuation mask is not patterned. 
     
     
       5. The touch sensor panel of  claim 3 , wherein the attenuation mask is patterned. 
     
     
       6. The touch sensor panel of  claim 5 , wherein the pattern of the attenuation mask is such that the attenuation mask does not overlap an alignment feature included in the same material layer as the first touch electrodes. 
     
     
       7. The touch sensor panel of  claim 1 , wherein:
 the component is a light-absorptive layer formed on the first side or the second side of the substrate. 
 
     
     
       8. A method of fabricating a touch sensor panel, the method comprising:
 forming a first plurality of touch electrodes on a first side of a substrate of the touch sensor panel; 
 forming a second plurality of touch electrodes on a second side of the substrate of the touch sensor panel; and 
 forming and activating a first passivation layer on the first side of the substrate and a second passivation layer on the second side of the substrate, 
 wherein a component of the touch sensor panel, other than the first plurality of touch electrodes and the second plurality of touch electrodes, is configured to prevent light configured to activate the passivation layer during the activation from being transmitted from the first side of the substrate to the second side of the substrate, the component configured with a transmissivity less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. 
 
     
     
       9. The method of  claim 8 , wherein:
 the component is the substrate. 
 
     
     
       10. The method of  claim 8 , wherein:
 the component is an attenuation mask formed in a same material layer as the first plurality of touch electrodes. 
 
     
     
       11. The method of  claim 10 , wherein the attenuation mask is not patterned. 
     
     
       12. The method of  claim 10 , wherein the attenuation mask is patterned. 
     
     
       13. The method of  claim 12 , wherein the pattern of the attenuation mask is such that the attenuation mask does not overlap an alignment feature included in the same material layer as the first touch electrodes. 
     
     
       14. The method of  claim 10 , wherein:
 the component is a light-absorptive layer formed on the first side or the second side of the substrate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 62/742,038, filed Oct. 5, 2018, the entire disclosure of which is incorporated herein by reference for all purposes. 
    
    
     FIELD OF THE DISCLOSURE 
     This relates generally to touch sensor panels, and more particularly to touch sensor panel designs that control the transmission of light, for activating passivation layers in the touch sensor panels, from one side of the substrate of the touch sensor panels to the other. 
     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 sensor panels 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 sensor panels 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 sensor panel, as described above. Some touch sensor panels 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). 
     SUMMARY OF THE DISCLOSURE 
     Examples of the disclosure are directed to various touch sensor panel designs that include structure and/or process steps for controlling the amount of light that reaches the other side of the substrate of the touch sensor panels during fabrication, thus preventing unwanted photo-activation of passivation layers during the fabrication. Some examples include an integrated attenuation mask. In some examples, the attenuation mask is solid and in some examples the attenuation mask is patterned. Some examples include a light-absorptive substrate. Some examples include a light-absorptive layer formed on the substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1E  illustrate example systems that can use light-transmissivity controlling techniques according to examples of the disclosure. 
         FIG. 2  illustrates an example computing system including a touch sensor panel that can use light-transmissivity controlling techniques according to examples of the disclosure. 
         FIG. 3A  illustrates an exemplary touch sensor circuit corresponding to a self-capacitance measurement of a touch node electrode and sensing circuit according to examples of the disclosure. 
         FIG. 3B  illustrates an exemplary touch sensor circuit corresponding to a mutual-capacitance drive line and sense line and sensing circuit according to examples of the disclosure. 
         FIG. 4A  illustrates touch sensor panel with touch electrodes arranged in rows and columns according to examples of the disclosure. 
         FIG. 4B  illustrates touch sensor panel with touch node electrodes arranged in a pixelated touch node electrode configuration according to examples of the disclosure. 
         FIG. 5A  illustrates a touch sensor panel with column electrodes and row electrodes according to examples of the disclosure. 
         FIGS. 5B-5C  illustrate a cross section of the touch sensor panel in  FIG. 5A  during an exemplary fabrication process for the touch sensor panel according to some examples of the disclosure. 
         FIG. 6A  illustrates an example of the disclosure in which an attenuation mask is integrated into the touch sensor panel stackup according to some examples of the disclosure. 
         FIG. 6B  illustrates an example of the disclosure in which a substrate in a touch sensor panel stackup is light-absorptive according to some examples of the disclosure. 
         FIG. 6C  illustrates an example of the disclosure in which a light-absorptive layer is formed on a substrate in a touch sensor panel stackup according to some examples of the disclosure. 
         FIGS. 7A-7C  illustrate various patterns of an attenuation mask and/or light-absorptive layer in a touch sensor panel stackup according to some examples of the disclosure. 
         FIG. 8  illustrates an example of the disclosure in which a patterned glass mask is used in conjunction with a patterned attenuation mask (or light-absorptive layer) to control the final intensity of light reaching the other side of a substrate of the touch sensor panel according to examples of the disclosure. 
         FIG. 9A  illustrates a top view of an exemplary touch sensor panel according to some examples of the disclosure. 
         FIG. 9B  illustrates a bottom view of an exemplary touch sensor panel according to some examples of the disclosure. 
         FIG. 10A  illustrates a top view of an exemplary touch sensor panel according to some examples of the disclosure. 
         FIG. 10B  illustrates a bottom view of an exemplary touch sensor panel according to some examples of the disclosure. 
         FIG. 11  illustrates an exemplary process for forming a touch sensor panel including light-transmissibility controlling techniques according to some examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     Examples of the disclosure are directed to various touch sensor panel designs that include structure and/or process steps for controlling the amount of light that reaches the other side of the substrate of the touch sensor panels during fabrication, thus preventing unwanted photo-activation of passivation layers during the fabrication. Some examples include an integrated attenuation mask. In some examples, the attenuation mask is solid and in some examples the attenuation mask is patterned. Some examples include a light-absorptive substrate. Some examples include a light-absorptive layer formed on the substrate. 
       FIGS. 1A-1E  illustrate example systems that can use light-transmissivity controlling techniques according to examples of the disclosure.  FIG. 1A  illustrates an example mobile telephone  136  that includes a touch screen  124  that can use light-transmissivity controlling techniques according to examples of the disclosure.  FIG. 1B  illustrates an example digital media player  140  that includes a touch screen  126  that can use light-transmissivity controlling techniques according to examples of the disclosure.  FIG. 1C  illustrates an example personal computer  144  that includes a touch screen  128  that can use light-transmissivity controlling techniques according to examples of the disclosure.  FIG. 1D  illustrates an example tablet computing device  148  that includes a touch screen  130  that can use light-transmissivity controlling techniques according to examples of the disclosure.  FIG. 1E  illustrates an example wearable device  150  that includes a touch screen  132  and can be attached to a user using a strap  152  and that can use light-transmissivity controlling techniques according to examples of the disclosure. It is understood that a touch screen and light-transmissivity controlling techniques can be implemented in other devices as well. Additionally it should be understood that although the disclosure herein primarily focuses on touch screens, the disclosure of light-transmissivity controlling techniques can be implemented for devices including touch sensor panels (and displays) that may not be implemented as a touch screen. 
     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. 4B ). For example, a touch sensor panel 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 sensor panel 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 sensor panel/panel. Such a touch sensor panel can be referred to as a pixelated self-capacitance touch sensor panel, though it is understood that in some examples, the touch node electrodes on the touch sensor panel can be used to perform scans other than self-capacitance scans on the touch sensor panel (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 sensor panel. 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 sensor panel 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 (e.g., as described below with reference to  FIG. 4A ) 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. 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 sensor panel. 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 arrange as a matrix of small, individual plates of conductive material (e.g., as in touch node electrodes  408  in touch sensor panel  402  in  FIG. 4B ) or as drive lines and sense lines (e.g., as in row touch electrodes  404  and column touch electrodes  406  in touch sensor panel  400  in  FIG. 4A ), 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 that can use light-transmissivity controlling techniques 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. 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 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, including the configuration of switches, 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. 3A  illustrates an exemplary touch sensor circuit  300  corresponding to a self-capacitance measurement of a touch node electrode  302  and sensing circuit  314  (e.g., corresponding to a sense channel  208 ) according to examples of the disclosure. Touch node electrode  302  can correspond to a touch electrode  404  or  406  of touch sensor panel  400  or a touch node electrode  408  of touch sensor panel  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. 3B  illustrates an exemplary touch sensor circuit  350  corresponding to a mutual-capacitance drive line  322  and sense line  326  and sensing circuit  314  (e.g., corresponding to a sense channel  208 ) 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. 3B  illustrates a general case in which both resistive and capacitive feedback elements are utilized. The sense signal (referred to as V in ) 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 yin 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. 
     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. 4A  illustrates touch sensor panel  400  with touch electrodes  404  and  406  arranged in rows and columns according to examples of the disclosure. Specifically, touch sensor panel  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 sensor panel  400 , and can intersect with each other, as illustrated in  FIG. 4A . 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, touch sensor panel  400  can sense the self-capacitance of touch electrodes  404  and  406  to detect touch and/or proximity activity on touch sensor panel  400 , and in some examples, touch sensor panel  400  can sense the mutual capacitance between touch electrodes  404  and  406  to detect touch and/or proximity activity on touch sensor panel  400 . 
       FIG. 4B  illustrates touch sensor panel  402  with touch node electrodes  408  arranged in a pixelated touch node electrode configuration according to examples of the disclosure. Specifically, touch sensor panel  402  can include a plurality of individual touch node electrodes  408 , each touch node electrode identifying or representing a unique location on the touch sensor panel 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 sensor panel/touch screen, as previously described. Touch node electrodes  408  can be on the same or different material layers on touch sensor panel  402 . In some examples, touch sensor panel  402  can sense the self-capacitance of touch node electrodes  408  to detect touch and/or proximity activity on touch sensor panel  402 , and in some examples, touch sensor panel  402  can sense the mutual capacitance between touch node electrodes  408  to detect touch and/or proximity activity on touch sensor panel  402 . 
       FIG. 5A  illustrates touch sensor panel  500  with a plurality of column electrodes  506  and a plurality of row electrodes  504  according to examples of the disclosure. In some examples, touch sensor panel  500  can include one or more touch electrodes disposed as columns that form column electrodes  506  (e.g., single contiguous electrodes, or noncontiguous electrodes electrically coupled together using electrical bridges), and one or more touch electrodes disposed as rows that form row electrodes  504  (e.g., single contiguous electrodes, or noncontiguous electrodes electrically coupled together using electrical bridges), similar to touch sensor panel  400  described above with reference to  FIG. 4A . It should be understood that in some examples, touch sensor panel  500  can include a matrix of touch node electrodes, in a manner similar to touch sensor panel  402  described above with reference to  FIG. 4B . 
     Touch screen  500  can also include bond pads  508  that can facilitate electrical connections between row  504  and/or column electrodes  506  and other circuitry (e.g., touch sensing circuitry, driving circuitry, etc.). For example, touch sensor panel  500  can include bond pads  508  in the border region of touch sensor panel  500  (e.g., a region of the touch sensor panel that is peripheral to the location of the touch electrodes  504  and  506  and optionally one or more display pixels) that can be electrically connected to column electrodes  506  via traces. Touch sensor panel  500  can similarly include other bond pads  508  in the border region of touch sensor panel  500  for electrically connecting to other column electrodes  506  and row electrodes  504  on touch sensor panel. It is understood that in some examples, bond pads  508  can be outside of the border region, such as on a tail that is bent behind the touch sensor panel. 
     In some examples, touch electrodes  504  and  506  can be disposed on a touch sensor panel substrate. The substrate can include a rigid or flexible material to support the touch electrodes  504  and  506  and any other material layers included in the touch sensor panel stackup. In some examples, the substrate can include two or more substrate layers joined together by an adhesive. In some examples, it can be desirable for a passivation layer to cover all or substantially all of one side of the touch sensor panel substrate (e.g., while the other side has no or partial coverage of the passivation layer), at least in certain regions of the touch sensor panel, such as in the border regions of the touch sensor panel (e.g., to help guard against physical stress that can cause damage to the various parts of the touch sensor panel stackup, such as electrodes  504 / 506 ) during fabrication. 
     In instances where a photosensitive passivation layer is used on both sides of the substrate during the fabrication of the touch sensor panel, it can be difficult to achieve full coverage of the passivation layer on one side of the substrate when the other side has no coverage or partial coverage of the passivation layer. In some examples, the substrate can be substantially transparent (e.g., to allow for the touch sensor panel to be overlaid on or integrated with a display, such as in a touch screen), which can allow light (e.g., UV light) that is used to activate the photosensitive passivation layer during fabrication to pass through the substrate from one side of the substrate to the other. When light passes through the substrate in this way, the passivation layer can be activated in areas where photo-activation was not desired. 
     For example,  FIG. 5B  illustrates a cross section  502  of touch sensor panel  500  at A to A′ in  FIG. 5A  during an exemplary fabrication process for touch sensor panel  500  according to some examples of the disclosure. Cross section  502  can include substrate  510 , which can be the substrate on which the touch sensor panel is formed. As mentioned previously, substrate  510  can be transparent or substantially transparent (e.g., glass, plastic, etc.) to allow the touch sensor panel to be used in applications where light should be able to pass through the touch sensor panel during operation (e.g., as in a touch screen). In the example of  FIG. 5B , electrodes  506   a  and  506   b  (corresponding to column electrodes  506  in  FIG. 5A ) bond pad  508   a  (corresponding to a bond pad  508  in  FIG. 5A ) can be formed on the top side of substrate  510 . The bond pad  508   a  can be electrically connected to one (or more) of electrodes  506 . Electrode  504   a  (corresponding to row electrodes  504  in  FIG. 5A ) can be formed on the bottom side of substrate  510 . Thus, in the example of  FIG. 5B , all row electrodes  504  can be formed on the bottom side of substrate  510 , and all column electrodes  506  can be formed on the top side of substrate  510 , though it is understood that in some examples this can be reversed. Moreover, in some examples, the touch sensor panel  500  can include touch node electrodes similar to the touch node electrodes  408  of touch screen  402 . In examples where touch sensor panel  500  includes touch node electrodes, the touch node electrodes can be formed on one or both sides of substrate  510 . 
     In some examples, electrodes  504  and  506 , and bond pads  508  can each be formed of two layers: 1) a indium tin oxide (ITO) layer  520  that is formed on substrate  510 , and 2) a second metal layer  530  (e.g., copper, aluminum, gold, etc.) that is formed on the ITO layer. Once those two layers  520  and  530  have been formed and patterned, a passivation layer  512  can be formed (e.g., deposited, coated, laminated, etc.) on top of electrodes  504  and  506  on both sides of substrate  510 , as shown in  FIG. 5B . 
     The passivation layer  512  can be a photosensitive passivation layer, for example. In some examples, the passivation layer  512  can be formed by depositing a material layer and exposing portions of the material to light with particular characteristics (e.g., sufficient intensity, certain wavelengths, etc., such as UV light). The light can photo-activate portions of the material layer, causing those portions to remain in subsequent process steps (e.g., a post-activation rinse). In some examples, portions of material that are not exposed to light with the particular characteristics are not photo-activated and can therefore be removed in subsequent process steps. 
     In some examples, it can be desired to remove the passivation layer  512  from at least a portion of the bond pad  508   a  on substrate  510  (e.g., so that electrical contact can be made to bond pad  508   a , and thus to the electrode  506  to which bond pad  508   a  is coupled). After passivation layer  512  has been formed on both sides of substrate  510 , a masking layer  514  can be formed over at least a portion of bond pad  508   a  on the top side of substrate  510 , such in the area of the touch sensor panel where bond pad  508   a  is located (e.g., in the border region). In some examples, no masking layer is formed on the bottom side of substrate  510 . 
     After forming the masking layer  514 , light can be directed towards substrate  510  from both the top and bottom sides of substrate  510 . The light can cause photo-activation of portions  512   a  of passivation layer  512 , without photo-activating of portions  512   b  of passivation layer  512 . In particular, in some examples, the ITO layer  520  and metal layer  530  forming electrodes  504  and  506  and bond pad  508   a , and masking layer  514 , can be substantially opaque to the light used to photo-activated passivation layer  512 . Thus, light directed towards substrate  510  from above can terminate at masking layer  514  and areas that include electrodes  506   a  or bond pad  508   a , and light directed towards substrate  510  from below can terminate at electrode  504   a . However, light directed towards substrate  510  from below in areas outside of electrode  504   a  (e.g., below bond pad  508 ) can pass through substrate  510  and activate portions of passivation layer  512  that are under masking layer  514 . Specifically, passivation layer portion  512   a  under masking layer  514  can be activated by light directed towards substrate  510  from below. In some examples, in subsequent process steps, non-activated regions  512   b  of passivation layer  512  can be removed, while activated regions  512   a  of the passivation layer  512  can remain. Thus, in some examples, portions  512   a  of passivation layer  512  can remain in undesired regions of the touch sensor panel (e.g., in the border region of the touch sensor panel outside of bond pad  508   a ), as shown in  FIG. 5C . In particular, a portion  512   c  of the passivation layer to the right of bond pad  508   a  in  FIG. 5C  can be undesirable passivation coverage. 
     It is understood that while  FIGS. 5B and 5C  have been described with reference to bond pad  508   a  on the top side of substrate  510  that is connected to an electrode  506 , bond pads formed on the bottom side of substrate  510  that are connected to respective electrodes  504  can also require passivation layer  512  removal to allow for electrical contact to those bond pads. The above-described problem can similarly occur with respect to such bond pads on the bottom side of substrate  510 , with the relevant details simply being reversed from the top side of substrate  510  to the bottom side of substrate  510  (e.g., the masking layer  514  can be formed on the bottom side of substrate  510  over such bond pads, and undesired activation of portions of passivation layer  512  can result from light entering from the top side of substrate  510  and passing through to the bottom side of substrate). 
       FIGS. 6-11  illustrate various examples of the disclosure that can address the above issue.  FIG. 6A  illustrates an exemplary touch sensor panel stackup  600  having an integrated an attenuation mask  616  according to some examples of the disclosure. In particular, the details of  FIG. 6A  can be that of  FIG. 5B , except where otherwise noted, and  FIG. 6A  can continue to illustrate a cross-section A to A′ of the touch sensor panel of  FIG. 5A . 
     Stackup  600  can include an integrated attenuation mask  616 . Attenuation mask  616  can be formed of and in the same materials/layers as electrodes  504   a  on the bottom side of substrate  610  (e.g., an ITO layer  620  formed on substrate  610 , and a second metal layer  630  formed on the ITO layer). The attenuation mask  616  can be disposed between the passivation layer  612  on the bottom side of substrate  610  and substrate  610 . Thus, attenuation mask  616  can be patterned during the same patterning step used to pattern electrodes  504   a  on the bottom side of substrate  610 . In some examples, attenuation mask  616  can be formed throughout the bottom side of substrate  610 , and in other examples, attenuation mask  616  may only be formed on the bottom side of substrate  610  in the bond pad/border regions of the touch sensor panel (e.g., outside of areas of the touch sensor panel in which electrodes  504  are formed). 
     With the inclusion of attenuation mask  616  on the bottom side of substrate  610 , as shown in  FIG. 6A , light directed towards substrate  610  from below can terminate at attenuation mask  616  and/or electrodes  504 , rather than passing through to passivation layer  612  on the top side of substrate  610 . Thus, the activation of regions of the passivation layer  612  on the top side of substrate can be controlled by light directed towards substrate  610  from above, without being impacted by light directed towards substrate  610  from below. Therefore, mask layer  614 , for example, can define regions  612   a  of the passivation layer to be activated by the light and regions  612   b  of the passivation layer not to be activated by the light on the top side of substrate  610 . It is understood that the examples of  FIG. 6A  can equally be applied to areas of the touch sensor panel at which bond pads on the bottom side of substrate  610  are located (e.g., bond pads that electrically couple to electrodes  504  on the bottom side of substrate  610 ). In such examples, attenuation mask  616  would be formed on the top side of substrate  610 , and mask layer  614  would be formed on the bottom side of substrate  610 , for example. 
       FIG. 6B  illustrates an exemplary touch sensor panel stackup  601  including a light-absorptive substrate  610  according to some examples of the disclosure. In particular, the details of  FIG. 6B  can be that of  FIG. 5B , except where otherwise noted, and  FIG. 6B  can continue to illustrate a cross-section A to A′ of the touch sensor panel of  FIG. 5A . 
     Substrate  610  can be a substrate that is substantially not light-transmissive (e.g., transmissivity less than or equal to a transmissivity threshold that only allows light through substrate  610  at intensities less than the activation intensity threshold of passivation layer  612 ). In some examples, substrate  610  can be transmissive to visible light (e.g., to maintain usability with a touch screen) but not transmissive to light used to activate passivation layer  612  (e.g., UV light). In other words, the substrate  610  can have higher transmissivity for visible light and lower transmissivity for passivation layer-activation light. In some example, substrate  610  can have bulk material properties that results in such transmissivity, and in some examples, substrate  610  can include one or more layers (e.g., not bulk) that are light-absorptive and that result in such transmissivity. 
     In the example of  FIG. 6B , similar to as described with reference to  FIG. 6A , as shown in  FIG. 6B , light directed towards substrate  610  from below can terminate at or within substrate  610  and/or electrodes  604 , rather than passing through to passivation layer  612  on the top side of substrate  610 . Thus, the activation of regions of the passivation layer  612  on the top side of substrate can be controlled by light directed towards substrate  610  from above, and not light directed towards substrate  610  from below. Therefore, mask layer  614 , for example, can define regions  612   a  of the passivation layer that can be activated by the light and regions  612   b  of the passivation layer that may not be activated by the light on the top side of substrate. It is understood that the examples of  FIG. 6B  can equally be applied to areas of the touch sensor panel at which bond pads on the bottom side of substrate  610  are located (e.g., bond pads that electrically couple to electrodes  604  on the bottom side of substrate  610 ). In such examples, mask layer  614  would be formed on the bottom side of substrate  610 , for example. 
       FIG. 6C  illustrates an exemplary touch sensor panel stackup  603  including a light-absorptive layer  618  according to some examples of the disclosure. In particular, the details of  FIG. 6C  can be that of  FIG. 5B , except where otherwise noted, and  FIG. 6C  can continue to illustrate a cross-section A to A′ of the touch sensor panel of  FIG. 5A . 
     In some examples, a light-absorptive layer  618  can be formed on substrate  610  (e.g., on substrate  610 , between the ITO/metal layers that form electrodes  604  and  606  and bond pads  608 , and substrate  610 ). In some examples, light-absorptive layer  618  can be blanket formed across the entirety of substrate  610 , on the top and/or bottom surfaces of substrate  610 , and/or formed only in certain regions of substrate  610  (e.g., in the bond pad/border regions of the touch sensor panel, such as outside of areas of the touch sensor panel in which electrodes  604 / 606  are formed). Light-absorptive layer  618  can be a material layer that is substantially not light-transmissive (e.g., transmissivity less than or equal to a level that only allows light through substrate  610  at intensities less than the activation intensity threshold of passivation layer  612 ). In some examples, light-absorptive layer  618  can be transmissive to visible light (e.g., to maintain usability with a touch screen) but not transmissive to light used to activate passivation layer  612  (e.g., UV light). In other words, the light-absorptive layer  618  can have higher transmissivity for visible light and lower transmissivity for passivation layer-activation light. 
     In the example of  FIG. 6C , similar to as described with reference to  FIGS. 6A and 6B , as shown in  FIG. 6C , light directed towards substrate  610  from below can terminate at or within light-absorptive layer  618  and/or electrodes  604 , rather than passing through to passivation layer  612  on the top side of substrate  610 . Thus, the activation of regions of the passivation layer  612  on the top side of substrate can be controlled by light directed towards substrate  610  from above, and not light directed towards substrate  610  from below. Therefore, mask layer  614 , for example, can define regions  612   a  of the passivation layer  612  that can be activated by the light and regions  612   b  of the passivation layer that may not be activated by the light on the top side of substrate  610  (e.g., regions of passivation layer  612  on the top side of substrate  610  under mask layer  614  can remain non-activated). It is understood that the examples of  FIG. 6C  can equally be applied to areas of the touch sensor panel at which bond pads on the bottom side of substrate  610  are located (e.g., bond pads that electrically couple to electrodes  504  on the bottom side of substrate  610 ). In such examples, mask layer  614  would be formed on the bottom side of substrate  610 , for example. 
     As mentioned above, attenuation mask  616  and/or light-absorptive layer  618  may only be sufficiently opaque to the light used to activate passivation layer  612  such that the intensity of light that reaches the other side of substrate  610  is below the activation intensity threshold of passivation layer  612 . Thus, while in some examples, attenuation mask  616  and/or light-absorptive layer  618  can be contiguous/solid, in other examples, attenuation mask  616  and/or light-absorptive layer  618  can be patterned.  FIGS. 7A-7C  illustrate exemplary patterns that can be applied to attenuation mask  616  and/or light-absorptive layer  618  according to some examples of the disclosure. Attenuation mask  616  and/or light-absorptive layer  618  can be formed with a pattern, such as circle patterns in  FIG. 7A , square patterns in  FIG. 7B , or hexagon patterns in  FIG. 7C . In some examples, electrodes  504 / 506  can be solid or patterned in the same way as attenuation mask  616  and/or light-absorptive layer  618 . As long as attenuation mask  616  and/or light-absorptive layer  618  are patterned such that the intensity of the light that reaches the other side of substrate  610  is below the activation intensity threshold of passivation layer  612 , the results of  FIGS. 6A-6C  can be achieved. 
     In some examples, the intensity of light able to pass through patterned attenuation mask  616  and/or light-absorptive layer  618  can be a function of the pattern size/shape of the attenuation mask  616  and/or light-absorptive layer  618 . Additionally, in some examples, it can be beneficial to pattern attenuation mask  616  and/or light-absorptive layer  618  rather than have them be solid material layers for various reasons. For example, material corrosion considerations can dictate a patterned attenuation mask  616  and/or light-absorptive layer  618 , which can prevent corrosion that might occur at the edge of the touch sensor panel (e.g., due to die cutting) from propagating further into the touch sensor panel (which might occur if attenuation mask  616  and/or light-absorptive layer  618  were solid, contiguous materials). As another example, a patterned attenuation mask  616  can reduce parasitic capacitive coupling that might exist between bond pads  608  and the attenuation mask  616  that is opposite the bond pads  608  on substrate  610  (e.g., by reducing the area of the attenuation mask  616 ). Alternatively, in some examples, attenuation mask  616  can be formed of a solid, contiguous material layer (e.g., ITO plus other metal) that can be floating or coupled to a reference voltage (e.g., ground, other reference voltage, etc.) to reduce parasitic capacitive coupling that might exist between bond pads  608  and the attenuation mask  616  that is opposite the bond pads  608  on substrate  610 . 
     With respect to patterning of attenuation mask  616  and/or light-absorptive layer  618 , in some examples, the opaque areas of attenuation mask  616  and/or light-absorptive layer  618  can be larger than the metal patterning resolution of the fabrication process used, the transparent areas of attenuation mask  616  and/or light-absorptive layer  618  can be smaller than the passivation layer patterning resolution of the fabrication process used, and/or attenuation mask  616  and/or light-absorptive layer  618  can be designed/patterned such that the final light intensity that is able to reach the passivation layer on the other side of substrate  610  is less than the activation intensity threshold of the passivation layer. For example, the attenuation mask  616  and/or light-absorptive layer  618  pattern can be made up of a number of unit cells (e.g., rectangular- or square-shaped) of which a certain portion is opaque (e.g., includes metal or light-absorptive layer) and a remaining portion is transparent (e.g., does not include metal or light-absorptive layer). In some examples, the lateral dimensions of the unit cell (e.g., in both axes) can range from a minimum feature size of the metal pattern (e.g., 5, 10, 15 um) to a minimum pattern size of the passivation layer (e.g., 25, 30, 35 um). In some examples, the lateral dimensions of the unit cell (e.g., in both axes) can range from 1×UV wavelength (e.g., 364 nm, I-line) to 100×UV wavelength (36.4 nm, I-line). 
     In some examples, a separate, patterned glass mask can be combined with the attenuation mask  616  and/or light-absorptive layer  618  examples disclosed above to further control or refine the transmissivity of the light-controlling examples of the disclosure.  FIG. 8  illustrates an exemplary touch sensor panel stackup  800  including a patterned glass mask  820  and a patterned attenuation mask  816  (or light-absorptive layer) to control the final intensity of light reaching the other side of substrate  610  according to examples of the disclosure. The stackup  800  can include passivation layers  812  on the top and bottom of substrate  810 , patterned attenuation mask  816  on the top side of substrate  810  (e.g., between the passivation layer  812  on the top side of substrate  810  and substrate  810 ), and a patterned glass mask  820   a  on top of the passivation layer  812  on the top side of substrate  810 . A non-patterned glass mask  820   b  can be on the bottom side of passivation layer  812  on the bottom side of substrate  810 . 
     In some examples, the patterns of glass mask  820   a  and attenuation mask  816  can be such that, together, the light directed towards substrate  810  from above can be attenuated to below the activation intensity threshold of passivation layer  812  by the time the light reaches the bottom side of substrate  810 . Further, solid glass mask  820   b  can prevent light directed towards substrate  810  from below from activating the passivation layer  812  on the bottom side of substrate  810 . As such, after the light-activation step of the fabrication process, passivation layer  812   a  can be activated (e.g., by light from above), and passivation layer  812   b  can be non-activated. Glass mask  820   a  and attenuation mask  816  can be patterned pursuant to the criteria previously described to achieve the above-described results, and it is understood that, as above, glass mask  820   a  and/or attenuation mask  816  can be utilized on the top and/or bottom sides of substrate  810 , depending on which side of substrate  810  should not include a passivation layer. Combining glass mask  820   a  with attenuation mask  816  allows the use of less metal area in the attenuation mask  816  layer (e.g., which would allow for more light to pass through the attenuation mask  816  layer) that might otherwise be used, which can be beneficial if problems associated with more metal in the attenuation mask  816  layer are observed (e.g., parasitic capacitance and/or corrosion-related problems, as previously discussed). 
     In some examples, the attenuation mask can be patterned in a manner that does not overlap one or more alignment features included in the touch sensor panel.  FIG. 9A  illustrates a top view of an exemplary touch sensor panel  900  according to some examples of the disclosure. In some examples, the touch sensor panel  900  can include traces  906  of metal layer (e.g., metal layers  520 ,  530 ,  620 , or  630 ) and top passivation  912   a . The traces  906  can be touch sensors or traces connecting the touch sensors to a bond pad, for example. In some examples, the traces  908  can include an alignment feature  908  that is used later in the manufacturing process when assembling touch sensor panel  900  into an electronic device including other components, such as a display, circuitry, bezel, etc. As shown in  FIG. 9A , in some examples, the passivation layer does not completely cover the top of the touch sensor panel  900 . For example, a masking layer similar to masking layer  514  or  614  can be used to prevent passivation from being deposited in one or more regions of the top of the touch sensor panel. In some examples, other techniques, such as any of the other techniques disclosed herein, can be used. 
       FIG. 9B  illustrates a bottom view of the exemplary touch sensor panel  900  according to some examples of the disclosure.  FIG. 9B  illustrates the traces  906  and alignment feature  908  described above with reference to  FIG. 9A . The touch sensor panel further includes attenuation mask  916  and bottom passivation  912   b . Attenuation mask  916  can be patterned at locations that prevent passage of light from the bottom of the touch sensor panel stackup at locations between traces  906 . Moreover, in some examples, attenuation mask  916  may not overlap with alignment feature  908 . By patterning attenuation mask  916  in way that does not overlap with alignment feature  908 , alignment feature  908  remains visible during subsequent steps of assembling the electronic device that includes touch sensor panel  900 . In some examples, the attenuation mask  916  is solid with the exception of locations that doe not include the attenuation mask  916  (e.g., attenuation mask  916  is not patterned in one of the ways described above with reference to  FIGS. 7A-7C ). In some examples, however, attenuation mask  916  is patterned in the manner shown in  FIG. 9B  and in a manner illustrated in or similar to one or more of  FIGS. 7A-7C . For example, an electrode patterned as shown in  FIGS. 7A-7C  is disposed in regions of the electronic device as shown in FIG.  9 B. As shown in  FIG. 9B , in some examples, the passivation layer does not completely cover the bottom of the touch sensor panel  900 . For example, a masking layer similar to masking layer  514  or  614  can be used to prevent passivation from being deposited in one or more regions of the bottom of the touch sensor panel that are not covered by attenuation mask  906 . In some examples, other techniques, such as any of the other techniques disclosed herein, can be used. 
       FIG. 10A  illustrates a top view of an exemplary touch sensor panel  1000  according to some examples of the disclosure. Touch sensor panel  1000  includes metal traces  1006 , ITO traces  1007 , and top passivation  1012   a . The metal traces  1006  can be included in a metal layer similar to metal layer  530  or  630  and the ITO traces  1007  can be included in an ITO layer similar to ITO layer  520  or  620 . Metal traces  1006  can be touch sensor electrodes, part(s) of the bond pad, and/or conductive traces to the touch sensor electrodes or the bond pad, for example. The ITO traces  1007  can similarly be touch sensor electrodes, part(s) of the bond pad, and/or conductive traces to the touch sensor electrodes or the bond pad. In some examples, a layer of ITO can be disposed beneath the metal traces  1006 . 
     Metal traces  1006  can include a first alignment feature  1008 A and a second alignment feature  1008 B, for example. In some examples, alignment feature  1008 A and/or  1008 B can be used in later fabrication steps of the electronic device including the touch sensor panel  1000 . For example, alignment feature  1008 A and/or  1008 B can be used to properly align display hardware, other circuitry, and/or a bezel relative to the touch sensor panel  1000 . In some examples, the top passivation  1012   a  may not overlap alignment feature  1008 A. 
     ITO traces  1007  can include a section of ITO  1009  not covered by a metal trace  1006 . In some examples, the section of ITO  1009  can be used to adhere upper passivation  1012   a  to the rest of the touch sensor panel  1000 . In some examples, including the section of ITO  1009  can prevent the upper passivation  1009  from peeling during subsequent fabrication steps of the touch sensor panel  1000 . 
     As shown in  FIG. 10A , in some examples, the passivation layer does not completely cover the top of the touch sensor panel  1000 . For example, a masking layer similar to masking layer  514  or  614  can be used to prevent passivation from being deposited in one or more regions of the top of the touch sensor panel  1000 . In some examples, other techniques, such as any of the other techniques disclosed herein, can be used. 
       FIG. 10B  illustrates a bottom view of the exemplary touch sensor panel  1000  according to some examples of the disclosure. The bottom view of the touch sensor panel  1000  can include bottom passivation covering the entire section of the bottom of the touch sensor panel  1000  shown in  FIG. 10B . In some examples, the entire bottom surface of the touch sensor panel is covered by bottom passivation. Beneath bottom passivation, the touch sensor panel  1000  can include an attenuation mask  1016 , which can be patterned to reveal alignment feature  1008 B and one or more metal traces  1006  and/or ITO traces  1007  (e.g., a stackup of ITO traces  1007  and metal traces  1006 ). In some examples, the attenuation mask  1016  can be a continuous layer of material or can be patterned as shown in one or more of  FIGS. 7A-7C . 
     In some examples, bottom passivation is fully or partially transparent, enabling alignment feature  1008 B to be visible during subsequent fabrication steps of the electronic device incorporating touch sensor panel  1000  (e.g., forming/installing display circuitry, other circuitry, device housing or bezel). 
       FIG. 11  illustrates an exemplary process  1100  for forming a touch sensor panel including light-transmissibility controlling techniques according to some examples of the disclosure. For example, one or more of the touch sensor panels described above with reference to  FIGS. 1A-9B  can be formed according to process  1100 . 
     In some examples, at  1102 , a plurality of touch electrodes can be formed on one side of the substrate. The touch electrodes can be formed as row and column electrodes similar to those described above with reference to  FIG. 4A  or as touch node electrodes as described above with reference to  FIG. 4B , for example. In some examples, either row electrodes  404  or column electrodes  406  can be formed on one side of the substrate and the other of the row or column electrodes can be formed on the other side of the substrate at  1104 , described below. Forming the touch electrodes can include forming a layer of ITO similar to layer  520  or  620  and forming a metal layer similar to layer  530  or  630 , for example. In some examples, one or more alignment features (e.g., alignment features  908 ,  1008   a  or  1008   b ) can be formed while forming the touch electrodes. 
     In some examples, at  1104 , a plurality of touch electrodes can be formed on the other side of the substrate. The electrodes can be formed as row and column electrodes similar to those described above with reference to  FIG. 4A  or as touch node electrodes described above with reference to  FIG. 4B , for example. In some examples, when one of row electrode or column electrodes were formed on one side of the substrate at  1102 , the other of row and column electrodes can be formed on the other side of the substrate. Thus, in some examples, the touch sensor panel can include row electrodes on a first side of the substrate and column electrodes on a second side of the substrate. Forming the touch electrodes can include forming a layer of ITO similar to layer  520  or  620  and forming a metal layer similar to layer  530  or  630 , for example. In some examples, one or more alignment features (e.g., alignment features  908 ,  1008   a  or  1008   b ) not formed at  1102  can be formed while forming the touch electrodes at  1104 . 
     In some examples, at  1106 , a light-absorptive component of the touch sensitive display can be formed. For example, an attenuation mask  616  can be formed on the bottom side of the substrate, including material in ITO layer  620  and metal layer  630 . In some examples, the attenuation mask can be patterned according to one or more of  FIGS. 7A-7C, 9B , or  10 B. In some examples, the attenuation mask is a solid material layer patterned according to  FIG. 9B or 10B . As another example, the light-absorptive component can be the substrate. For example, the substrate  610  can be formed of a material that absorbs light having a characteristic that activates the passivation layer (e.g., UV light) and transmits visible light. Thus, in some examples forming the light-absorptive component  1106  can be executed before forming the touch electrodes  1102 - 1104 . As another example, in some examples, the light-absorptive component can be a light-absorptive layer  618 . In some examples, the light-absorptive layer can be formed on a material layer different from the ITO layer  620  and the metal layer  630 . As shown in  FIG. 6C , the light-absorptive layer can be disposed between touch electrodes  604   a  and substrate  610 . Thus, in some examples, forming the light-absorptive component  1106  can occur before or between forming the touch electrodes  1102 - 1104 . In some examples, an additional masking layer  614  can be formed after passivation  1108  is formed. 
     In some examples, at  1108 , passivation (e.g., passivation  512 ,  612 ,  812 ,  912 ,  1012 ) can be formed on both sides of the substrate. The passivation can be formed from a transparent non-conductive material that becomes activated when exposed to light having a particular characteristic (e.g., light having at least a threshold intensity, light that is persistent for at least a threshold period of time, light that has a particular wavelength, such as UV light), for example. 
     In some examples, at  1110 , the passivation formed at  1108  can be activated. For example, the passivation can be activated by exposing the touch sensor panel to activating light from both sides of the substrate. In some examples, portions of the passivation that are activated will remain when other portions of the passivation are removed at  1112 . 
     In some examples, at  1112 , parts of the passivation not activated by the light can be removed. For example, the touch sensor panel can be exposed to a chemical that removes portions of the passivation that were not activated by the light that was applied at  1110 . For example, a portion of the passivation overlapping a bond pad of the touch sensor panel can be removed, enabling subsequent formation of an electrical connection to the bond pad. 
     Thus, in some examples, a touch sensor panel can be formed according to process  1100 . Additional or alternate operations can be performed when forming the touch sensor panel and the order in which operations  1102 - 1112  are performed can vary depending on the design of the touch sensor panel. 
     Therefore, according to the above, some examples of the disclosure are directed to touch sensor panel designs that selectively prevent light with enough intensity to activate the passivation layer used in the touch sensor panels to reach the passivation layer on the opposite side of the substrates of the touch sensor panels. 
     In accordance with the above, some examples of the disclosure are directed to a touch sensor panel comprising: a substrate including a first side and a second side; a passivation layer; a first plurality of touch electrodes formed on the first side of the substrate; and a second plurality of touch electrodes formed on the second side of the substrate, wherein a component of the touch sensor panel, other than the first plurality of touch electrodes and the second plurality of touch electrodes, is configured to prevent light configured to activate the passivation layer during fabrication of the touch sensor panel from being transmitted from the first side of the substrate to the second side of the substrate. Additionally or alternatively to the above, in some examples, the component is the substrate, and the substrate is configured with a transmissivity less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. Additionally or alternatively to the above, in some examples, the component is an attenuation mask formed in a same material layer as the first plurality of touch electrodes. Additionally or alternatively to the above, in some examples, the attenuation mask is not patterned. Additionally or alternatively to the above, in some examples, the attenuation mask is patterned. Additionally or alternatively to the above, in some examples, the pattern of the attenuation mask is such that a transmissivity of the patterned attenuation mask is less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. Additionally or alternatively to the above, in some examples, the component is a light-absorptive layer formed on the first side or the second side of the substrate, and the light-absorptive layer is configured with a transmissivity less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. 
     Some examples of the disclosure are directed to a method of fabricating a touch sensor panel, the method comprising: forming a first plurality of touch electrodes on a first side of a substrate of the touch sensor panel; forming a second plurality of touch electrodes on a second side of the substrate of the touch sensor panel; and forming and activating a first passivation layer on the first side of the substrate and a second passivation layer on the second side of the substrate, wherein a component of the touch sensor panel, other than the first plurality of touch electrodes and the second plurality of touch electrodes, is configured to prevent light configured to activate the passivation layer during the activation from being transmitted from the first side of the substrate to the second side of the substrate. Additionally or alternatively to the above, in some examples, the component is the substrate, and the substrate is configured with a transmissivity less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. Additionally or alternatively to the above, in some examples, the component is an attenuation mask formed in a same material layer as the first plurality of touch electrodes. Additionally or alternatively to the above, in some examples, the attenuation mask is not patterned. Additionally or alternatively to the above, in some examples, the attenuation mask is patterned. Additionally or alternatively to the above, in some examples, the pattern of the attenuation mask is such that a transmissivity of the patterned attenuation mask is less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. Additionally or alternatively to the above, in some examples, the component is a light-absorptive layer formed on the first side or the second side of the substrate, and the light-absorptive layer is configured with a transmissivity less than or equal to a transmissivity threshold at which an intensity of the light transmitted from the first side of the substrate to the second side of the substrate is equal to an activation intensity threshold of the passivation layer. 
     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: 20190927
Publication Date: 20210706
Grant Date: 20210706
Priority Date: 20181005
Inventors: LEE, SEUNG HOON
CHOI, JI HUN
TUNG, CHUN-HAO
KANG, SUNGGU
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F2203/04112", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0418", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04112", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0418", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 70052017