PATENT DOCUMENT

Publication Number: US-10901543-B1
Application Number: US-201816145034-A
Country: US
Kind Code: B1

Title: Touch screen with transparent electrode structure

Abstract:
Transparent conductors including a silver layer with high transparency and low sheet resistance are described. In some examples, the silver layer can be located between two transparent conductive oxide layers. The transparent conductor can further include additional transparent conductive oxide layers, optical layers, and/or additional conductive layers (e.g., layers including ITO or another fully or partially transparent conductive material), for example. In some examples, transparent conductors including a silver layer can be included in a touch screen device. For example, one or more shielding layers or one or more touch electrodes can include transparent conductors with a silver layer. In some examples, the silver layer can improve transparency, sheet resistance, and/or infrared reflection characteristics of the transparent conductor.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a transparent conductor comprising:
 a layer of Zinc-Tin-Oxide (ZnSnO); and 
 a layer of silver; 
 
 one or more display pixels disposed in a first layer of a touch screen stackup of the electronic device; and 
 a plurality of touch electrodes disposed in a second layer of a touch screen stackup of the electronic device, wherein:
 the transparent conductor is disposed in a respective layer of the touch screen stackup of the electronic device, the respective layer between the first layer of the touch screen stackup that includes the one or more display pixels and the second layer of the touch screen stackup that includes the touch electrodes, and 
 the transparent conductor is coupled to a shielding voltage. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein the layer of ZnSnO is a first layer of ZnSnO, the transparent conductor further comprising:
 a second layer of ZnSnO, wherein the layer of silver is located between the first layer of ZnSnO and the second layer of ZnSnO. 
 
     
     
       3. The electronic device of  claim 2 , wherein the second layer of ZnSnO has a thickness of in the range of 10-40 nanometers. 
     
     
       4. The electronic device of  claim 1 , wherein the transparent conductor further comprises:
 a layer of Zinc Oxide (ZnO), wherein the layer of silver is located between the layer of ZnSnO and the layer of ZnO. 
 
     
     
       5. The electronic device of  claim 4 , wherein the layer of ZnO has a thickness in the range of 1-4 nanometers. 
     
     
       6. The electronic device of  claim 1 , wherein the transparent conductor further comprises:
 a layer of Silicon Dioxide (SiO 2 ), wherein the layer of silver is located between the layer of ZnSnO and the layer of SiO 2 . 
 
     
     
       7. The electronic device of  claim 6 , wherein the layer of SiO 2  has a thickness in the range of 20-150 nanometers. 
     
     
       8. The electronic device of  claim 1 , wherein the transparent conductor further comprises:
 a plastic substrate, wherein the layer of ZnSnO is located between the plastic substrate and the layer of silver. 
 
     
     
       9. The electronic device of  claim 1 , wherein the layer of ZnSnO is a first layer of ZnSnO, and the transparent conductor further comprises:
 a second layer of ZnSnO; 
 a layer of ZnO, the layer of ZnO located between the layer of silver and the second layer of ZnSnO; 
 a layer of SiO 2 , the layer of SiO 2  located such that the second layer of ZnSnO is located between the layer of SiO 2  and the layer of ZnO; and 
 a plastic substrate; wherein the first layer of ZnSnO is located between the plastic substrate and the layer of silver. 
 
     
     
       10. The electronic device of  claim 9 , wherein:
 the first layer of ZnSnO has a thickness in the range of 20-50 nanometers, 
 the layer of silver has a thickness in the range of 3 to 12 nanometers, 
 the layer of ZnO has a thickness in the range of 1-4 nanometers, 
 the second layer of ZnSnO has a thickness in the range of 10-40 nanometers, and 
 the layer of SiO 2  has a thickness in the range of 20-150 nanometers. 
 
     
     
       11. The electronic device of  claim 1 , wherein the layer of silver has a thickness in the range of 3 to 12 nanometers. 
     
     
       12. The electronic device of  claim 1 , wherein the layer of ZnSnO has a thickness in the range of 20-50 nanometers. 
     
     
       13. The electronic device of  claim 1 , wherein the transparent conductor further comprises:
 a layer of indium gallium zinc oxide (IGZO) located such that the silver layer is between the layer of IGZO and the layer of ZnSnO. 
 
     
     
       14. The electronic device of  claim 13 , wherein the transparent conductor further comprises:
 a plastic substrate, wherein 
 the layer of ZnSnO is located between the plastic substrate and the layer of silver, 
 the layer of ZnSnO has a thickness in the range of 20-50 nanometers, 
 the layer of silver has a thickness in the range of 3-12 nanometers, and 
 the layer of IGZO has a thickness in the range of 20-50 nanometers. 
 
     
     
       15. The electronic device of  claim 1 , wherein the layer of silver comprises a silver alloy including on or more of bismuth, copper, platinum, and nickel. 
     
     
       16. The electronic device of  claim 15 , wherein the silver alloy is gradient-doped. 
     
     
       17. The electronic device of  claim 1 , wherein the transparent conductor further comprises:
 a layer of amorphous conductive material, wherein the layer of silver is located between the layer of ZnSnO and the layer of amorphous conductive material. 
 
     
     
       18. An electronic device comprising:
 a transparent conductor comprising:
 a layer of Indium-Tin-Oxide (ITO); 
 a layer of Zinc-Tin-Oxide (ZnSnO); and 
 a layer of silver located between the layer of ITO and the layer of ZnSnO; 
 
 one or more display pixels disposed in a first layer of a touch screen stackup of the electronic device; and 
 a plurality of touch electrodes disposed in a second layer of the touch screen stackup of the electronic device, wherein:
 the transparent conductor is disposed in a respective layer of the touch screen stackup of the electronic device, the respective layer between the first layer of the touch screen stackup that includes the one or more display pixels and the second layer of the touch screen stackup that includes the touch electrodes, and 
 the transparent conductor is coupled to a shielding voltage. 
 
 
     
     
       19. The electronic device of  claim 18 , wherein the transparent conductor further comprises:
 a layer of ZnO located between the layer of ITO and the layer of silver. 
 
     
     
       20. The electronic device of  claim 19 , wherein the layer of ZnO has a thickness in the range of 1-4 nanometers. 
     
     
       21. The electronic device of  claim 18 , wherein the transparent conductor further comprises:
 a layer of ZnO located between the layer of ITO and the layer of silver; and 
 a plastic substrate, wherein the layer of ZnSnO is located between the plastic substrate and the layer of silver, wherein: 
 the layer of ITO has a thickness in the range of 10-50 nanometers, 
 the layer of ZnO has a thickness in the range of 1-4 nanometers, 
 the layer of silver has a thickness in the range of 3 to 12 nanometers, and 
 the layer of ZnSnO has a thickness in the range of 10-50 nanometers. 
 
     
     
       22. The electronic device of  claim 18 , wherein the layer of silver has a thickness in the range of 3 to 12 nanometers. 
     
     
       23. The electronic device of  claim 18 , wherein the layer of ZnSnO has a thickness in the range of 10-50 nanometers.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 USC 119(e) of U.S. Provisional Patent Application No. 62/565,989, filed Sep. 29, 2017, the contents of which are incorporated herein by reference in their entirety for all purposes and of U.S. Provisional Patent Application No. 62/644,768, filed Mar. 19, 2018, the contents of which are incorporated herein by reference in their entirety for all purposes. 
    
    
     FIELD OF DISCLOSURE 
     This relates to transparent conductors, and in particular to transparent conductors including a silver layer with high transparency and low sheet resistance. 
     BACKGROUND OF THE INVENTION 
     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 transparent 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 touch 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. The computing system can interpret the touch in accordance with one or more display images appearing at the time of the touch. The touch screen can perform one or more actions based on the touch. In the case of some touch screens, a physical touch on the display may not be needed to detect a touch. For example, in some capacitive-type touch screens, fringing electrical fields used to detect touch can extend beyond the surface of the display, and an touch object 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 example, the conductive plates can be formed from other materials including conductive polymers, metal mesh, graphene, nanowires (e.g., metallic nanowires) or nanotubes (e.g., carbon nanotubes). In order to detect such changes, in some examples, the touch electrodes can be coupled to sense circuitry using routing traces. 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. Some touch screens can be formed by at least partially integrating touch sensing circuitry into a display pixel stackup (i.e., a stack of material layers forming the display pixels). For example, touch screens can further include one or more shielding electrodes for mitigating the capacitive coupling of electrical noise to one or more touch sensing components (e.g., touch electrodes or routing traces) of the touch screen. In some examples, these one or more shielding electrodes can be formed from a highly conductive material (e.g., a material with low sheet resistance) to increase the efficacy of the shielding. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     This relates to transparent conductors, and in particular to transparent conductors including a silver layer with high transparency and low sheet resistance. In some examples, transparent conductors including a silver layer can be incorporated into touch screen devices to form shielding electrodes and/or touch electrodes. The silver layer can be located between two oxide layers to protect the silver layer and improve transparency of an electrode including the transparent conductor, for example. In some examples, the electrode further includes additional layers, such as additional oxide layers, optical layers, and/or one or more transparent conductive layers (e.g., including ITO). The transparent conductors can be used as a continuous electrode or can be patterned to form patterned electrodes, for example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1D  illustrate an example mobile telephone, an example media player, an example personal computer, and an example tablet computer that can each include an exemplary touch screen according to examples of the disclosure. 
         FIG. 2  illustrates a block diagram of an example computing system that illustrates one implementation of an example self-capacitance touch screen according to examples of the disclosure. 
         FIG. 3A  illustrates an exemplary touch sensor circuit corresponding to a self-capacitance 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. 4  illustrates a top view of an exemplary touch screen including touch electrodes arranged in rows and columns according to examples of the disclosure. 
         FIG. 5  illustrates touch screen with touch node electrodes arranged in a pixelated touch node electrode configuration according to examples of the disclosure. 
         FIGS. 6A-6B  illustrate exploded views of an exemplary touch screen according to examples of the disclosure. 
         FIG. 6C  illustrates an exemplary stackup of a touch screen according to examples of the disclosure. 
         FIGS. 7A-D  illustrate exemplary electrode stackups according to examples of the disclosure. 
         FIG. 8  illustrates an exemplary electrode stackup according to examples of the disclosure. 
         FIGS. 9A-9I  illustrate exemplary steps of forming an electrode stackup according to 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. 
     This relates to transparent conductors, and in particular to transparent conductors including a silver layer with high transparency and low sheet resistance. In some examples, transparent conductors including a silver layer can be incorporated into touch screen devices to form shielding electrodes and/or touch electrodes. The silver layer can be located between two oxide layers to protect the silver layer and improve transparency of an electrode including the transparent conductor, for example. In some examples, the electrode further includes additional layers, such as additional oxide layers, optical layers, and/or one or more transparent conductive layers (e.g., including ITO). The transparent conductors can be used as a continuous electrode or can be patterned to form patterned electrodes, for example. 
       FIGS. 1A-1D  illustrate an example mobile telephone  136 , an example media player  140 , an example personal computer  144 , and an example tablet computer  148  that can each include an exemplary touch screen  124 - 128  according to examples of the disclosure. 
       FIG. 1A  illustrates an example mobile telephone  136  that includes a touch screen  124 .  FIG. 1B  illustrates an example digital media player  140  that includes a touch screen  126 .  FIG. 1C  illustrates an example personal computer  144  that includes a touch screen  128 .  FIG. 1D  illustrates an example tablet computer  148  that includes a touch screen  130 . It is understood that the above touch screens can be implemented in other devices as well, including in wearable devices. 
     In some examples, touch screens  124 ,  126 ,  128  and  130  can be based on self-capacitance. A self-capacitance based touch system can include a matrix of small, individual plates of conductive material that can be referred to as touch node electrodes (as described below with reference to touch screen  220  in  FIG. 2  and with reference to touch screen  502  in  FIG. 5 ). For example, a touch screen can include a plurality of individual touch node electrodes, each touch node electrode identifying or representing a unique location (e.g., a touch node) 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. 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 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 (as described below with reference to touch screen  400  in  FIG. 4 ), 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  and  130  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, 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 screen. In some examples, the electrodes of a mutual-capacitance based touch system can be formed from a matrix of small, individual plates of conductive material, and changes in the mutual capacitance between plates of conductive material can be detected, similar to above. 
     In some examples, touch screens  124 ,  126 ,  128  and  130  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 screen  502  in  FIG. 5 ) or as drive lines and sense lines (e.g., as in touch screen  502  in  FIG. 5 ), 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 a block diagram of an example computing system  200  that illustrates one implementation of an example self-capacitance touch screen  220  according to examples of the disclosure. It is understood that computing system  200  can include a mutual capacitance touch screen, as described above, though the examples of the disclosure will be described in the context of a self-capacitance touch screen. Computing system  200  can be included in, for example, mobile telephone  136 , digital media player  140 , personal computer  144 , tablet computer  148 , or any mobile or non-mobile computing device that includes a touch screen such as a wearable device. Computing system  200  can include a touch screen 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  and channel scan logic  210 . Channel scan logic  210  can access RAM  212 , autonomously read data from sense channels  208 , and provide control for the sense channels. In addition, channel scan logic  210  can control sense channels  208  to generate stimulation signals at various frequencies and phases that can be selectively applied to the touch nodes 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 within touch screen  220  itself. 
     Touch screen  220  can be used to derive touch information at multiple discrete locations of the touch screen, referred to herein as touch nodes. For example, touch screen  220  can include touch sensing circuitry that can include a capacitive sensing medium having a plurality of electrically isolated touch node electrodes  222  (e.g., a plurality of touch node electrodes of pixelated self-capacitance touch screen). Touch node electrodes  222  can be coupled to sense channels  208  in touch controller  206 , can be driven by stimulation signals from the sense channels through drive/sense interface  225 , and can be sensed by the sense channels through the drive/sense interface as well, as described above. 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, touch node electrodes  222  may be directly connected to sense channels or indirectly connected to sense channels via drive/sense interface  225 , but in either case provided an electrical path for driving and/or sensing the touch node electrodes  222 . Labeling the conductive plates used to detect touch (i.e., touch node electrodes  222 ) as “touch node” electrodes can be particularly useful when touch screen  220  is viewed as capturing an “image” of touch (e.g., a “touch image”). In other words, after touch controller  206  has determined an amount of touch detected at each touch node electrode  222  in touch screen  220 , the pattern of touch node electrodes in the touch screen at which a touch occurred can be thought of as a touch image (e.g., a pattern of fingers touching the touch screen). In such examples, each touch node electrode in a pixelated self-capacitance touch screen can be sensed for the corresponding touch node represented in the touch image. 
     Computing system  200  can also 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, such as an LCD driver  234  (or an LED display or OLED display driver). The LCD 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 as described in more detail below. Host processor  228  can use LCD 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 . 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. 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. 
       FIG. 3A  illustrates an exemplary touch sensor circuit  300  corresponding to a self-capacitance touch node electrode  302  and sensing circuit  314  according to examples of the disclosure. Touch node electrode  302  can correspond to touch node electrode  222 . 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 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  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 be altered. This change in mutual capacitance  324  can be detected to indicate a touch or proximity event at the touch node, as described previously and below. 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 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 0  to keep V 1  substantially equal to V ref , and can therefore maintain V 1  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 stackups 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  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 . 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. 5  illustrates touch screen  502  with touch node electrodes  508  arranged in a pixelated touch node electrode configuration according to examples of the disclosure. Specifically, touch screen  502  can include a plurality of individual touch node electrodes  508 , 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  508  can be on the same or different material layers on touch screen  502 . In some examples, touch screen  502  can sense the self-capacitance of touch node electrodes  508  to detect touch and/or proximity activity on touch screen  502 , and in some examples, touch screen  502  can sense the mutual capacitance between touch node electrodes  508  to detect touch and/or proximity activity on touch screen  502 . 
     In some examples, one or more electrodes (e.g., electrodes  404 ,  406 , or  508 ) included in a touch screen (e.g., touch screen  400  or touch screen  502 ) can be formed using techniques and/or materials based on percent light transmission and/or sheet resistance. As will be discussed in more detail below, the inclusion of a thin layer of silver in a transparent conductor stack-up can provide a low sheet resistance (e.g., around 10-20 or 12 ohm/sq) while still allowing for a high percentage (e.g., around 85%-95%, over 90%, over 94%, or 94%) of light transmission in the visible light spectrum. 
       FIG. 6A  illustrates an exploded view of an exemplary touch screen  600  according to examples of the disclosure. In some examples, touch screen  600  can include display circuitry  602 , touch circuitry  620 , and a cover material  610  (e.g., a cover glass). Display circuitry  602  and touch circuitry  620  can be joined together by a first optically clear adhesive  604 , for example. In some examples, display circuitry  602  and cover material  610  can be joined together by a second optically clear adhesive  608 . Display circuitry  620  can include a plurality of touch electrodes  622  (e.g., touch electrodes  404 ,  406 , or  408 ) and a plurality of first low-resistance conductors  624  (e.g., routing traces), for example. In the example of  FIG. 6A , the touch electrodes are illustrated in an arrangement of rows and columns. In some examples, touch circuitry  620  can be formed to exhibit characteristics in region  518  or  520  of graph  500  (i.e., with high percent light transmission and low sheet resistance). In this way, an image displayed by display circuitry  602  can be visible through touch circuitry  620  and touch circuitry can exhibit good electrical performance. As described above, a shielding layer (e.g., bottom shielding) may be disposed between the display circuitry  602  and touch circuitry  620  to prevent interference between the display and the touch circuitry.  FIG. 6B  illustrates an exploded view of the exemplary touch screen  600  having touch electrodes  622  arranged in a pixelated configuration. Accordingly, it should be understood that the physical arrangement of touch electrodes can be varied without departing from the scope of the present disclosure. 
       FIG. 6B  illustrates an exploded view of the exemplary touch screen  600  having touch electrodes  622  arranged in a pixelated configuration. Accordingly, it should be understood that the physical arrangement of touch electrodes can be varied without departing from the scope of the present disclosure. 
       FIG. 6C  illustrates an exemplary stackup of a touch screen  600  according to examples of the disclosure. In particular,  FIG. 6C  corresponds to the pixelated touch electrode  622  configuration illustrated in  FIG. 6B , but it should be understood that a corresponding stackup using the electrode configuration illustrated in  FIG. 6A  can be used without departing from the scope of the present disclosure. In some examples, touch screen  600  can include touch electrodes  622 , first low-resistance conductors  624  (e.g., routing traces), first shielding  626 , and second shielding  628 . First shielding  626  can be electrically coupled to circuitry (not shown) by second low-resistance conductors  632  (e.g., vias), for example. In some examples, second shielding  628  can be coupled to circuitry (not shown) by second low resistance conductors  634  (e.g., vias). Second low-resistance conductors  632  and  634  (e.g., vias) can be disposed in an outer region (e.g., a border region) around an inner region (e.g., a display region) of the touch screen  600 , for example. In some examples, touch screen  600  can further include opaque mask  636  (e.g., black mask), which can be located on top of low-resistance conductors  632 ,  624 , and  634  to fully or partially conceal the vias from a user&#39;s view when the device is assembled. 
     In some examples, touch circuitry  620  can include a first substrate  630  and a second substrate  640 . Touch electrodes  622  and first shielding  626  can be formed on first substrate  630  such that first substrate  630  is a two-layer structure, for example. In some examples, touch electrodes  622  and first shielding  626  can include ITO and first substrate  630  can be a DITO (double ITO) substrate. Second shielding  628  can be formed on second substrate  640 , for example. In some examples, second shielding  628  can include ITO and second substrate  640  can be a SITO (single ITO) substrate. In some examples, touch screen  600  can further include a third adhesive  606  joining together the elements formed on first substrate  630  and the elements formed on second substrate  640 . In some examples, substrates  630  and  640  can each be a transparent insulating material layer that provides structural support to one or more material layers placed on the substrate (e.g., one or more other layers or components). Further, in some examples, each substrate  630  and  640  can include one or more substrates joined together by one or more adhesives (not shown). In some examples, additional or alternative structures and/or layers can be included in touch screen  600  without departing from the scope of the present disclosure. For example, one or more conductive layers can serve an additional or alternative purpose to those discussed with reference to  FIGS. 6A-6C . 
       FIG. 7A  illustrates an exemplary electrode stackup  701  according to examples of the disclosure. Electrode stackup  701  can include substrate  703  (e.g., substrate  630  or  640  illustrated in  FIGS. 6A-6B ) and electrode  705 , for example. In some examples (e.g., a plastic substrate) the substrate  703  material surface may not adhere well to the electrode  705  material due to material characteristics of the substrate. Electrode  705  can be used to form touch electrodes  622 , first shielding  626 , or second shielding  628  disclosed above with reference to  FIGS. 6A-6B , for example. In some examples, stackup  701  can include one or more additional layers. The additional layers can provide mechanical support and/or structure, adhere other layers together, or improve the optical characteristics of stackup  701 , for example. In some examples, layers with other functions are possible. 
     In some examples, electrode  705  can include a silver layer  707 . Silver layer  707  can include pure silver or a silver alloy including a dopant such as bismuth, copper, platinum, and/or nickel in concentrations of 1%-2% or 1%-10%, for example. In some examples, the type and concentration of dopant can depend on the materials used in other layers of the stackup  701  and the processing techniques used to deposit one or more layers of the stackup. For example, the type and concentration of dopant can be selected based on the type of material and type of deposition technique used to form oxide layers  709  and  711  closest to the silver layer  709 . In some examples, silver layer  707  can be formed of multiple layers of silver alloy and pure silver where one or more layers include different materials and/or concentrations of dopant. In some examples, the silver alloy can be gradient-doped, meaning the concentrations of dopant vary with respect to position within the silver layer. Silver alloy can be more resistant to oxidation and corrosion than pure silver, for example. In some examples, the silver layer  707  can have a minimum thickness of at least about 3 nanometers. In some examples, the silver layer  707  can have a minimum thickness of at least about 5 nanometers. In some examples, the silver layer  707  can have a maximum thickness of at most about 20 nanometers. In some examples, the silver layer  707  can have a maximum thickness of at most about 12 nanometers, for example. In some examples, silver layer  707  can be between 5 nm to 10 nm nanometers thick or about 6 nm thick. The thickness of silver layer  707  can be selected to allow visible light from a display (e.g., display circuitry  602 ) to be transmitted through the silver layer while also maintaining a suitably low sheet resistance to reliably conduct electrical signals, for example. 
     In some examples, silver layer  707  can be disposed on a first oxide layer  709 , which can act as a seed to manufacture the silver layer. For example, first oxide layer  709  can provide a smooth surface on which to grow the silver layer, which can allow the silver layer to be deposited with a smooth surface and uniform thickness thereby improving the light transmission and haze performance of stackup  701 . First oxide layer  709  can include an optically clear oxide material (e.g., Zinc-Tin-oxide (ZnSnO) or Indium-gallium-zinc-oxide (IGZO)), for example. In some examples, when the first oxide layer  709  includes IGZO, the IGZO can be in an amorphous state and stackup  701  can be formed without annealing. In particular, in contrast to an ITO layer, an IGZO layer may not require annealing to reduce one or more of the sheet resistance and contact resistance of the first oxide layer  709 , as IGZO with Ag-layer has a low resistance (e.g., around 10-20 or 10-50 ohms per square) even in the amorphous state, for example. Forming stackup  701  without annealing can, for example, avoid degrading substrate  703  during fabrication that can be caused by exposure to excessive heat. In some examples, the first oxide layer  709  can have a thickness of about 20 to 50 nanometers. 
     In some examples, a second oxide layer  711  can be located on the silver layer  707  on a side opposite from the side where the first oxide layer  709  is located. The second oxide layer  711  can include a same material (e.g., ZnSnO or IGZO) or a different material (e.g., ZnO, ZnSnO, or IGZO) from the material included in the first oxide layer  709 . In some examples, the second oxide layer  711  can include a material that can be placed without the presence of oxygen deposition to reduce oxidation of the silver layer  707  while the second oxide layer is formed. As an example, the second oxide layer  711  can have a thickness of at least about 2 nanometers. In some examples, the second oxide layer  711  can have a thickness of about 1-4 nanometers. A third oxide layer  713  can be located on the second oxide layer  711 , for example. In some examples, the third oxide layer  713  can include a clear material, which can be the same material (e.g., ZnSnO or IGZO) included in the first oxide layer  709  or a different oxide material. As discussed above with respect to first oxide layer  709 , when the second oxide layer  711  and/or the third oxide layer  713  include IGZO, the IGZO can be in the amorphous state and stackup  701  can be formed without annealing. The third oxide layer  713  can have a thickness of about 10-40 nanometers, for example. 
     An optical layer  715  with optical properties complementing the optical properties of one or more of the first oxide layer  709 , silver layer  707 , second oxide layer  711 , and third oxide layer  713  can be located on the third oxide layer  711 , for example. In some examples, the optical layer  715  can be “index-matched to” (e.g., having a refractive index and/or a reflective index complementary of) one or more of the remaining layers of electrode  705 . Optical layer  715  can include a fully or partially transparent material (e.g., SiO 2 ). In some examples, optical layer  715  can have a thickness on the order of 20-150 nanometers. 
     In some examples, the combination of layers included in electrode  705  can yield an electrode having a high (e.g., around 85%-95%, over 90%, over 94%, or 94%) light transmission and relatively low (e.g., around 10-20 or 12 ohm/sq) sheet resistance. In particular, the sheet resistance of the combination of layers included in electrode  705  can be less than 20 ohms per square, and preferably less than about 12 ohms per square. When used as a shielding layer, the relatively low sheet resistance provided by the electrode  705  can be used as second shielding (e.g., second shielding  628 ) between touch circuitry and display circuitry of an electronic device, for example. Referring back to  FIG. 6B , a shielding signal can be electrically coupled to the electrode  705  for providing the shielding signal to the second shielding layer. The second low-resistance conductors  634  (e.g., vias) can be included only in a perimeter region of the touch screen and can be formed from a non-transparent conductor with a low resistance. The opaque layer  636  can block visibility of the second low-resistance conductors  634  (e.g., vias). The second low-resistance conductors  634  (e.g., vias) can electrically connect to one of the layers of the layer stackup shown in  FIG. 7A , e.g., layer  713 . In the event that layer  715  is an insulating layer (e.g., SiO 2 ), the layer  715  can be excluded in the perimeter region behind the opaque layer or have holes cut through to allow for contact between layer  713  and the second low-resistance conductors  634  (e.g., vias). The resistance through the thickness of layer  713  in series with the resistance of the second low-resistance conductors  634  (e.g., vias) can be the effective contact resistance for the contact with the silver layer  711 . Accordingly, even when the sheet resistance of layer  711  is made very low, a high contact resistance may counteract the benefits of the low sheet resistance of layer  711 . Further, in some examples, stackup  701  can be flexible, allowing it to be included in a foldable device with reduced risk of cracking. 
     In some examples, electrode  705  can be patterned to form touch electrodes (e.g., touch electrodes  622 ) or first shielding (e.g., first shielding  626 ) between the touch circuitry and a cover material of an electronic device. Although electrode  705  is illustrated as being located on substrate  703  without electrodes on the other side of the substrate, in some examples, substrate  703  can support electrodes on two of its sides. In some examples, substrate  703  can be a transparent insulating material layer that provides structural support to one or more material layers placed on the substrate (e.g., one or more other layers or components). Further, in some examples, substrate  703  can include one or more substrates joined together by one or more adhesives (not shown). 
       FIG. 7B  illustrates an exemplary electrode stackup  721  according to examples of the disclosure. Electrode stackup  721  can include substrate  723  (e.g., substrate  630  or  640  illustrated in  FIGS. 6A-6B ) and electrode  725 , for example. In some examples (e.g., a plastic substrate) the substrate  723  material surface may not adhere well to the electrode  725  material due to material characteristics of the substrate. Electrode  725  can be used to form touch electrodes  622 , first shielding  626 , or second shielding  628  disclosed above with reference to  FIGS. 6A-6B . In some examples, stackup  721  can include one or more additional layers. The additional layers can provide mechanical support and/or structure, adhere other layers together, or improve the optical characteristics of stackup  721 , for example. In some examples, layers with other functions are possible. 
     In some examples, electrode  725  can include a silver layer  727 . Silver layer  727  can include pure silver or a silver alloy including a dopant such as bismuth, platinum, and/or nickel in concentrations of 1%-2% or 1%-10%, for example. In some examples, the type and concentration of dopant can depend on the materials used in other layers of the stackup  721  and the processing techniques used to deposit one or more layers of the stackup. For example, the type and concentration of dopant can be selected based on the type of material and type of deposition technique used to form the oxide layers  729  and  731  closest to the silver layer  729 . In some examples, silver layer  727  can be formed of multiple layers of silver alloy and pure silver where one or more layers include different materials and/or concentrations of dopant. In some examples, the silver alloy can be gradient-doped, meaning the concentrations of dopant vary with respect to position within the silver layer. Silver alloy can be more resistant to oxidation and corrosion than pure silver, for example. The silver layer  727  can have a thickness on the order of 3 to 12 nanometers, for example. In some examples, silver layer  727  can be 5-10 nanometers thick or 6 nm thick. The thickness of silver layer  727  can be selected to allow light from a display (e.g., display circuitry  602 ) to be transmitted through the silver layer while also maintaining a suitable sheet resistance to reliably conduct electrical signals, for example. 
     In some examples, silver layer  727  can be located on a first oxide layer  729 , which can act as a seed to manufacture the silver layer. For example, first oxide layer  729  can provide a smooth surface on which to grow the silver layer, thereby improving the light transmission and haze performance of stackup  721 . First oxide layer  729  can include an optically clear oxide material (e.g., ZnSnO or IGZO), for example. In some examples, when the first oxide layer  729  includes IGZO, the IGZO can be in an amorphous state and stackup  721  can be formed without annealing. In particular, in contrast to an ITO layer, an IGZO layer may not require annealing to reduce one or more of the sheet resistance and the contact resistance of the first oxide layer  729 , as electrodes including IGZO can have a low sheet resistance (e.g., around 10-20 or 10-50 ohms per square) even in the amorphous state, for example. Forming stackup  721  without annealing can, for example, avoid degrading substrate  723  during fabrication that can be caused by exposure to excessive heat. In some examples, first oxide layer can have a thickness on the order of 10-50 nanometers. 
     In some examples, a second oxide layer  721  can be located on the silver layer  727  on a side opposite from the side where the first oxide layer  729  is located. The second oxide layer  731  can include a same material or a different material (e.g., ZnO) from the material included in the first oxide layer  729 . In some examples, the second oxide layer  731  can include a material that can be placed without the use of oxygen deposition to reduce oxidation of the silver layer  727  while the second oxide layer is formed. As an example, the second oxide layer  721  can have a thickness on the order of 1-4 nanometers. 
     A conductive layer  733  can be located on the second oxide layer  731 , for example. In some examples, conductive layer  733  can include a fully or partially transparent material (e.g., ITO). The conductive layer  733  can be index-matched to one or more other components of electrode  725  to increase transparency of electrode  725 , for example. In some examples, the conductive layer  733  can have a thickness on the order of 10-50 nanometers. As discussed above with respect to first oxide layer  729 , when the second oxide layer  731  includes IGZO, the IGZO can be in the amorphous state and stackup  721  can be formed without annealing. 
     In some examples, the combination of layers included in electrode  725  can yield an electrode having a relatively high (e.g., around 85%-95%, over 90%, over 94%, or 94%) percent light transmission and relatively low (e.g., around 10-20 or 12 ohm/sq) sheet resistance. In particular, the sheet resistance of the combination of layers included in electrode  725  can be less than 20 ohms per square, and preferably less than 12 ohms per square. Electrode  725  can be used as second shielding (e.g., second shielding  628 ) between touch circuitry and display circuitry of an electronic device, for example. Referring back to  FIG. 6B , a shielding signal can be electrically coupled to the electrode  705  for providing the shielding signal to the second shielding layer. The second low-resistance conductors  634  (e.g., vias) can be included only in a perimeter region of the touch screen and can be formed from a non-transparent conductor with a low resistance. The opaque layer  636  can block visibility of the second low-resistance conductors  634  (e.g., vias). The second low-resistance conductors  634  (e.g., vias) can electrically connect to one of the layers of the layer stackup shown in  FIG. 7A , e.g., layer  733 . The resistance through the thickness of layer  733  in series with the resistance of the second low-resistance conductors  634  (e.g., vias) can be the effective contact resistance for the contact with the silver layer  711 . Accordingly, even when the sheet resistance of layer  731  is made very low, a high contact resistance may counteract the benefits of the low sheet resistance of layer  731 . Accordingly, in some examples, ITO can provide a suitable contact resistance while also maintaining desired transmission characteristics of visible light. 
     In some examples, electrode  725  can be patterned to form touch electrodes (e.g., touch electrodes  622 ) or first shielding (e.g., first shielding  626 ) between the touch circuitry and a cover material of an electronic device. Although electrode  725  is illustrated as being located on substrate  723  without electrodes on the other side of the substrate, in some examples, substrate  723  can support electrodes on two of its sides. In some examples, substrate  723  can each be a transparent insulating material layer that provides structural support to one or more material layers placed on the substrate (e.g., one or more other layers or components). Further, in some examples, substrate  723  can include one or more substrates joined together by one or more adhesives (not shown). Further, in some examples, stackup  721  can be flexible, allowing it to be included in a foldable device with reduced risk of cracking. 
     In some examples, electrode stackup  701  and electrode stackup  721  can have different performance characteristics. For example, electrode stackup  701  can have improved optical transmission compared to electrode stackup  721  because third oxide layer  713  and optical layer  715  can have a higher percent visible light transmission than ITO layer  733 . In some examples, electrode stackup  721  can have improved electrical conductivity compared to electrode stackup  701  because ITO layer  733  can have improved electrical conductivity (i.e., lower sheet resistance) compared to third oxide layer  713  and optical layer  715 . In some examples, other tradeoffs and design considerations are possible. Further, additional factors such as the thickness of one or more material layers can impact the sheet resistance and/or percent light transmission of electrode stackup  701  or electrode stackup  721 . 
       FIG. 7C  illustrates an exemplary electrode stackup  741  according to examples of the disclosure. Electrode stackup  741  can include substrate  743  (e.g., substrate  630  or  640  illustrated in  FIGS. 6A-6B ) and electrode  745 , for example. In some examples (e.g., a plastic substrate) the substrate  743  material surface may not adhere well to the electrode  745  material due to material surface characteristics of the substrate. Electrode  745  can be used to form touch electrodes  622 , first shielding  626 , or second shielding  628  disclosed above with reference to  FIGS. 6A-6B . In some examples, stackup  741  can include one or more additional layers. The additional layers can provide mechanical support and/or structure, adhere other layers together, or improve the optical characteristics of stackup  741 , for example. In some examples, layers with other functions are possible. 
     In some examples, electrode  745  can include a silver layer  747 . Silver layer  747  can include pure silver or a silver alloy including a dopant such as bismuth, copper, platinum, and/or nickel in concentrations of 1%-2% or 1%-10%, for example. In some examples, the type and concentration of dopant can depend on the materials used in other layers of the stackup  741  and the processing techniques used to deposit one or more layers of the stackup. For example, the type and concentration of dopant can be selected based on the type of material and type of deposition technique used to form the oxide layers  749  and  751  closest to the silver layer  749 . In some examples, silver layer  747  can be formed of multiple layers of silver alloy and pure silver where one or more layers include different materials and/or concentrations of dopant. In some examples, the silver alloy can be gradient-doped, meaning the concentrations of dopant vary with respect to position within the silver layer. Silver alloy can be more resistant to oxidation and corrosion than pure silver, for example. The silver layer  747  can have a thickness on the order of 3 to 12 nanometers, for example. In some examples, silver layer  747  can be 5-10 nanometers thick or 6 nm thick. The thickness of silver layer  747  can be selected to allow light from a display (e.g., display circuitry  602 ) to be transmitted through the silver layer while also maintaining a suitable sheet resistance to reliably conduct electrical signals, for example. 
     In some examples, silver layer  747  can be located on a first oxide layer  749 , which can act as a seed to manufacture the silver layer. For example, first oxide layer  749  can provide a smooth surface on which to grow the silver layer, thereby improving the light transmission and haze performance of stackup  741 . First oxide layer  749  can include an optically clear oxide material (e.g., ZnSnO or IGZO), for example. In some examples, when the first oxide layer  749  includes IGZO, the IGZO can be in an amorphous state and stackup  741  can be formed without annealing. In particular, in contrast to an ITO layer, an IGZO layer may not require annealing to reduce one or more of the sheet resistance and contact resistance of the first oxide layer  749 , as IGZO with Ag-stack has a low resistance (e.g., around 10-20 or 10-50 ohms per square) even in the amorphous state, for example. Forming stackup  701  without annealing can, for example, avoid degrading substrate  743  during fabrication that can be caused by exposure to excessive heat. In some examples, first oxide layer  749  can have a thickness on the order of 10-50 nanometers. 
     In some examples, a second oxide layer  751  can be located on the silver layer  747  on a side opposite from the side where the first oxide layer  749  is located. The second oxide layer  751  can include a same material (e.g., ZnSnO or IGZO) or a different material (e.g., ZnO, ZnSnO, or IGZO) from the material included in the first oxide layer  749 . In some examples, the second oxide layer  751  can include a material that can be placed without the use of oxygen deposition to reduce oxidation of the silver layer  747  while the second oxide layer is formed. As discussed above with respect to first oxide layer  749 , when the second oxide layer  751  includes IGZO, the IGZO can be in the amorphous state and stackup  741  can be formed without annealing. As an example, the second oxide layer  751  can have a thickness on the order of 1-4 nanometers. 
     In some examples, the combination of layers included in electrode  745  can yield an electrode having a relatively high (e.g., around 85%-95%, over 90%, over 94%, or 94%) percent light transmission and relatively low (e.g., around 10-20 or 12 ohm/sq) sheet resistance. In particular, the sheet resistance of the combination of layers included in electrode  745  can be less than 20 ohms per square, and preferably less than 12 ohms per square. Electrode  745  can be used as second shielding (e.g., second shielding  628 ) between touch circuitry and display circuitry of an electronic device, for example. Referring back to  FIG. 6B , a shielding signal can be electrically coupled to the electrode  745  for providing the shielding signal to the second shielding layer. The second low-resistance conductors  634  (e.g., vias) can be included only in a perimeter region of the touch screen and can be formed from a non-transparent conductor with a low resistance. The opaque layer  636  can block visibility of the second low-resistance conductors  634  (e.g., vias). The second low-resistance conductors  634  (e.g., vias) can electrically connect to one of the layers of the layer stackup shown in  FIG. 7C , e.g., layer  751 . The resistance through the thickness of layer  751  in series with the resistance of the second low-resistance conductors  634  (e.g., vias) can be the effective contact resistance for the contact with the silver layer  747 . Further, in some examples, stackup  741  can be flexible, allowing it to be included in a foldable device with reduced risk of cracking. 
       FIG. 7D  illustrates an exemplary electrode stackup  761  according to examples of the disclosure. Electrode stackup  761  can include substrate  763  (e.g., substrate  630  or  640  illustrated in  FIGS. 6A-6B ) and electrode  765 , for example. In some examples (e.g., a plastic substrate) the substrate  763  material surface may not adhere well to the electrode  765  material due to material characteristics of the substrate. Electrode  765  can be used to form touch electrodes  622 , first shielding  626 , or second shielding  628  disclosed above with reference to  FIGS. 6A-6B . In some examples, stackup  761  can include one or more additional layers. The additional layers can provide mechanical support and/or structure, adhere other layers together, or improve the optical characteristics of stackup  761 , for example. In some examples, layers with other functions are possible. 
     In some examples, electrode  765  can include a silver layer  767 . The silver layer  767  can have a thickness on the order of 3 to 15 nanometers, for example. In some examples, silver layer  747  can be 5-10 nanometers thick or 6 nm thick. Silver layer  767  can be built from multiple distinct layers with varying concentrations of dopant within (or no dopant) in each of the individual silver layers  767 - 1 ,  767 - 2 , and  767 - 3 , for example. In some examples, the silver layers  767 - 1  and  767 - 3  can have higher concentration of dopant and can thus be more resistant to oxidation than a pure silver. In this way, silver layer  767 - 2  can be protected by silver layer  767 - 1  and  767 - 3 , for example. In some examples, silver layer  767 - 2  can be pure silver or a silver alloy with a lower concentration of dopant than that of silver layers  767 - 1  and  767 - 3 . In some examples, the three layers  767 - 1 ,  767 - 2 , and  767 - 3  can be deposited as discrete layers. In some examples, the  767 - 1 ,  767 - 2 , and  767 - 3  can actually be formed as a single silver layer that has a doping gradient through its thickness (i.e., the silver layer can be gradient-doped). For simplicity of explanation, the layers  767 - 1 ,  767 - 2 , and  767 - 3  will be described as distinct layers but it should be understood that a single layer (e.g., as described in  FIGS. 7A-7C  above) having a doping gradient or other variable doping through its thickness can also be used without departing from the scope of the present disclosure. One or more of silver layers  767 - 1 ,  767 - 2 , and  767 - 3  can be doped with one or more of bismuth, platinum, and/or nickel in concentrations of around 1% to 2%, for example. The thickness of silver layer  767  can be selected to allow light from a display (e.g., display circuitry  602 ) to be transmitted through the silver layer while also maintaining a suitable sheet resistance to reliably conduct electrical signals, for example. 
     In some examples, silver layer  767  can be located on a first oxide layer  769 , which can act as a seed to manufacture the silver layer. For example, first oxide layer  769  can provide a smooth surface on which to grow the silver layer  767 , thereby improving the light transmission and haze performance of stackup  761 . First oxide layer  769  can include an optically clear oxide material (e.g., ZnSnO or IGZO), for example. In some examples, when the first oxide layer  769  includes IGZO, the IGZO can be in an amorphous state and stackup  761  can be formed without annealing. In particular, in contrast to an ITO layer, an IGZO layer may not require annealing to reduce the contact resistance of the first oxide layer  769 , as electrodes including IGZO may have a low resistance (e.g., around 10-20 or 10-50 ohms per square) even in the amorphous state, for example. Forming stackup  761  without annealing can, for example, avoid degrading substrate  763  during fabrication that can be caused by exposure to excessive heat. In some examples, first oxide layer  769  can have a thickness on the order of 10-50 nanometers. 
     In some examples, a second oxide layer  771  can be located on the silver layer  767  on a side opposite from the side where the first oxide layer  769  is located. The second oxide layer  771  can include a same material (e.g., ZnSnO or IGZO) or a different material (e.g., ZnO, ZnSnO, or IGZO) from the material included in the first oxide layer  769 . In some examples, the second oxide layer  771  can include a material that can be placed without the presence of oxygen deposition to reduce oxidation of the silver layer  767  while the second oxide layer is formed. As an example, the second oxide layer  771  can have a thickness of at least about 2 nanometers. In some examples, the second oxide layer  771  can have a thickness of about 1-4 nanometers. A third oxide layer  763  can be located on the second oxide layer  771 , for example. In some examples, the third oxide layer  773  can include a clear material, which can be the same material (e.g., ZnSnO or IGZO) included in the first oxide layer  769  or a different oxide material. As discussed above with respect to first oxide layer  769 , when the second oxide layer  771  and/or the third oxide layer  773  include IGZO, the IGZO can be in the amorphous state and stackup  761  can be formed without annealing The third oxide layer  773  can have a thickness of about 10-40 nanometers, for example. 
     An optical layer  775  with optical properties complementing the optical properties of one or more of the first oxide layer  769 , silver layer  767 , second oxide layer  771 , and third oxide layer  773  can be located on the third oxide layer  771 , for example. In some examples, the optical layer  775  can be “index-matched to” (e.g., having a refractive index and/or a reflective index complementary of) one or more of the remaining layers of electrode  765 . Optical layer  775  can include a fully or partially transparent material (e.g., SiO 2 ). In some examples, optical layer  775  can have a thickness on the order of 20-150 nanometers. 
     In some examples, the combination of layers included in electrode  765  can yield an electrode having a relatively high (e.g., around 85%-95%, over 90%, over 94%, or 94%) percent light transmission and relatively low (e.g., around 10-20 or 12 ohm/sq) sheet resistance. In particular, the sheet resistance of the combination of layers included in electrode  745  can be less than 20 ohms per square, and preferably less than 12 ohms per square. Electrode  745  can be used as second shielding (e.g., second shielding  628 ) between touch circuitry and display circuitry of an electronic device, for example. Referring back to  FIG. 6B , a shielding signal can be electrically coupled to the electrode  745  for providing the shielding signal to the second shielding layer. The second low-resistance conductors  634  (e.g., vias) can be included only in a perimeter region of the touch screen and can be formed from a non-transparent conductor with a low resistance. The opaque layer  636  can block visibility of the second low-resistance conductors  634  (e.g., vias). The second low-resistance conductors  634  (e.g., vias) can electrically connect to one of the layers of the layer stackup shown in  FIG. 7D , e.g., layer  771 . The resistance through the thickness of layer  751  in series with the resistance of the second low-resistance conductors  634  (e.g., vias) can be the effective contact resistance for the contact with the silver layer  747 . Further, in some examples, stackup  761  can be flexible, allowing it to be included in a foldable device with reduced risk of cracking. 
       FIG. 8  illustrates an exemplary electrode stackup  800  according to examples of the disclosure. In some examples, electrode stackup  800  can include a substrate  801 , a first electrode layer  810 , and a second electrode layer  820 . For example, first electrode layer  810  can include a first conductive layer  811 , second conductive layer  813 , first silver layer  817 , and first passivation  819 . In some examples, second electrode layer  820  can include third conductive layer  821 , fourth conductive layer  823 , second silver layer  823 , and second passivation  829 . For example, conductive layers  811 ,  813 ,  821  and  823  can include a conductive material (e.g., ITO or another fully or partially transparent conductive material). 
     In some examples, first electrode layer  810  can be patterned to create a plurality of electrically isolated electrodes. For example, the electrodes can be electrically isolated by passivation  819 , which can include an insulating and/or non-corrosive material. First silver layer  817  can conduct an electrical signal, transmit visible light (e.g., produced by display circuitry disposed beneath electrode stackup  800 ), and reflect infrared light, for example. In some examples, first silver layer  817  can reflect infrared light emitted by the sun, thereby reducing the amount of solar heating of the electrode stackup  800 . 
     In some examples, second electrode layer  820  can be patterned to create a plurality of electrically isolated electrodes. For example, the electrodes can be electrically isolated by passivation  829 , which can include an insulating and/or non-corrosive material. Second silver layer  827  can conduct an electrical signal, transmit visible light (e.g., produced by display circuitry disposed beneath electrode stackup  800 ), and reflect infrared light, for example. In some examples, second silver layer  827  can reflect infrared light emitted by the sun, thereby reducing the amount of solar heating of the electrode stackup  800 . 
     In some examples, substrate  801  can each be a transparent insulating material layer that provides structural support to one or more material layers placed on the substrate (e.g., one or more other layers or components). Further, in some examples, substrate  801  can include one or more substrates joined together by one or more adhesives (not shown). Substrate  801  can include the first electrode layer  810  and the second electrode layer  820 , making substrate  801  a two layer structure, for example. In some examples, electrode layers  810  and  820  can include ITO, making substrate  801  a DITO substrate. Although  FIG. 8  illustrates substrate  801  as supporting two layers of electrodes, in some examples, substrate  801  can support a single electrode layer (i.e., substrate  801  can be a one layer structure and/or a SITO substrate). In some examples, electrode stackup  800  can include additional or alternative components not illustrated in  FIG. 8 . For example, electrode stackup  800  can include oxide layers (e.g., one or more of oxide layers  709 ,  711 ,  713 ,  729 , and/or  931 ) and/or optical layers (e.g., optical layer  715 ). 
       FIGS. 9A-9I  illustrate exemplary steps of forming an electrode stackup  900  according to examples of the disclosure. In some examples, the electrode stackup  900  can be formed using a sputtering technique, a roll-to-roll coating method, or any other suitable technique.  FIG. 9A  illustrates providing an exemplary substrate  901  on which to support additional layers of electrode stackup  900  according to examples of the disclosure.  FIG. 9B  illustrates forming an exemplary first conductive layer  911  on substrate  901  according to examples of the disclosure. In some examples, first conductive layer  911  can include a conductive material (e.g., ITO or another fully or partially transparent conductive material).  FIG. 9C  illustrates forming a first silver layer  917  of electrode stackup  900  according to examples of the disclosure.  FIG. 9D  illustrates forming an exemplary second conductive layer  913  of electrode stackup  900  according to examples of the disclosure. In some examples, second conductive layer  913  can include a conductive material (e.g., ITO or another fully or partially transparent conductive material). First conductive layer  911 , second conductive layer  913 , and first silver layer  917  can form a first electrode layer  910  of electrode stackup  900 , for example. 
       FIG. 9E  illustrates forming an exemplary second electrode layer  920  according to examples of the disclosure. In some examples, second electrode layer  920  can include third conductive layer  921 , fourth conductive layer  923 , and second silver layer  927 . Third conductive layer  921  and fourth conductive layer  923  can include a conductive material (e.g., ITO or another fully or partially transparent conductive material), for example.  FIG. 9F  illustrates patterning exemplary second and fourth conductive layers  913  and  923  of electrode stackup  900  according to examples of the disclosure.  FIG. 9G  illustrates patterning exemplary first and second silver layers  917  and  927  of electrode stackup  900  according to examples of the disclosure.  FIG. 9H  illustrates patterning first and third  911  and  921  electrode layers of electrode stackup  900  according to examples of the disclosure.  FIG. 9I  illustrates forming exemplary passivation layers  919  and  929  of electrode stackup  900  according to examples of the disclosure. First passivation layer  919  and second passivation layer  929  can include insulating and/or non-corrosive materials, for example. 
     In some examples, electrode stackup  900  can include additional or alternative components not illustrated in  FIG. 8 . For example, electrode stackup  900  can include oxide layers (e.g., one or more of oxide layers  709 ,  711 ,  713 ,  729 , and/or  931 ) and/or optical layers (e.g., optical layer  715 ). In some examples, electrode stackup  900  can be formed using additional or alternative steps to those illustrated in  FIGS. 9A-9I . In some examples, one or more steps illustrate in  FIGS. 9A-9I  can be performed in an order different from the order illustrated in  FIGS. 9A-9I . 
     Some examples of the disclosure are related to a transparent conductor comprising: a layer of Zinc-Tin-Oxide (ZnSnO); and a layer of silver. Additionally or alternatively, in some examples the layer of ZnSnO is a first layer of ZnSnO, the transparent conductor further comprising: a second layer of ZnSnO, wherein the layer of silver is located between the first layer of ZnSnO and the second layer of ZnSnO. Additionally or alternatively, in some examples the second layer of ZnSnO has a thickness of in the range of 10-40 nanometers. Additionally or alternatively, in some examples the transparent conductor further includes a layer of Zinc Oxide (ZnO), wherein the layer of silver is located between the layer of ZnSnO and the layer of ZnO. Additionally or alternatively, in some examples the layer of ZnO has a thickness in the range of 1-4 nanometers. Additionally or alternatively, in some examples the transparent conductor further includes a layer of Silicon Dioxide (SiO 2 ), wherein the layer of silver is located between the layer of ZnSnO and the layer of SiO 2 . 
     Additionally or alternatively, in some examples the layer of SiO 2  has a thickness in the range of 20-150 nanometers. Additionally or alternatively, in some examples the transparent conductor further includes a plastic substrate, wherein the layer of ZnSnO is located between the plastic substrate and the layer of silver. Additionally or alternatively, in some examples the layer of ZnSnO is a first layer of ZnSnO, and the transparent conductor further includes a second layer of ZnSnO; a layer of ZnO, the layer of ZnO located between the layer of silver and the second layer of ZnSnO; a layer of SiO 2 , the layer of SiO 2  located such that the second layer of ZnSnO is located between the layer of SiO 2  and the layer of ZnO and a plastic substrate, wherein the first layer of ZnSnO is located between the plastic substrate and the layer of silver. Additionally or alternatively, in some examples the first layer of ZnSnO has a thickness in the range of 20-50 nanometers, the layer of silver has a thickness in the range of 3 to 12 nanometers, the layer of ZnO has a thickness in the range of 1-4 nanometers, the second layer of ZnSnO has a thickness in the range of 10-40 nanometers, and the layer of SiO2 has a thickness in the range of 20-150 nanometers. Additionally or alternatively, in some examples the layer of silver has a thickness in the range of 3 to 12 nanometers. Additionally or alternatively, in some examples the layer of ZnSnO has a thickness in the range of 20-50 nanometers. Additionally or alternatively, in some examples, the transparent conductor includes a layer of indium gallium zinc oxide (IGZO) located such that the silver layer is between the layer of IGZO and the layer of ZnSnO. Additionally or alternatively, in some examples, the transparent conductor further includes a plastic substrate, wherein the layer of ZnSnO has a thickness in the range of 20-50 nanometers, the layer of silver has a thickness in the range of 3-12 nanometers, and the layer of IGZO has a thickness in the range of 10-150 or 20-50 nanometers. Additionally or alternatively, in some examples the transparent conductor is included in a touch screen, the touch screen further comprising display circuitry and a plurality of touch electrodes, the transparent conductor is disposed between the display circuitry and the touch electrodes, and the transparent conductor is coupled to a shielding voltage. Additionally or alternatively, in some examples, the layer of silver comprises a silver alloy including on or more of bismuth, platinum, and nickel. Additionally or alternatively, in some examples, the transparent conductor further includes a layer of amorphous conductive material, wherein the layer of silver is located between the layer of ZnSnO and the layer of amorphous conductive material. 
     Some examples of the disclosure are related to a transparent conductor comprising: a layer of Indium-Tin-Oxide (ITO); a layer of Zinc-Tin-Oxide (ZnSnO); and a layer of silver located between the layer of ITO and the layer of ZnSnO. Additionally or alternatively, in some examples the transparent conductor further includes a layer of ZnO located between the layer of ITO and the layer of silver. Additionally or alternatively, in some examples the layer of ZnO has a thickness in the range of 1-4 nanometers. Additionally or alternatively, in some examples the transparent conductor further includes a plastic substrate, wherein the layer of ZnSnO is located between the plastic substrate and the layer of silver. Additionally or alternatively, in some examples the transparent conductor further includes a layer of ZnO located between the layer of ITO and the layer of silver; and a plastic substrate, wherein the layer of ZnSnO is located between the plastic substrate and the layer of silver. Additionally or alternatively, in some examples the layer of ITO has a thickness in the range of 10-50 nanometers, the layer of ZnO has a thickness in the range of 1-4 nanometers, the layer of silver has a thickness in the range of 3 to 12 nanometers, and the layer of ZnSnO has a thickness in the range of 10-50 nanometers. Additionally or alternatively, in some examples the layer of silver has a thickness in the range of 3 to 12 nanometers. Additionally or alternatively, in some examples the layer of ZnSnO has a thickness in the range of 10-50 nanometers. Additionally or alternatively, in some examples the transparent conductor is included in a touch screen, the touch screen further comprising display circuitry and a plurality of touch electrodes, the transparent conductor is disposed between the display circuitry and the touch electrodes, and the transparent conductor is coupled to a shielding voltage. 
     Although examples 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 the various examples as defined by the appended claims.

Metadata:
Filing Date: 20180927
Publication Date: 20210126
Grant Date: 20210126
Priority Date: 20170929
Inventors: BAYAT, Khadijeh
CHAN, ISAAC WING-TAK
CHEN, CHENG
YUEN, AVERY P.
DAS, RASMI R.
LE, HIENMINH HUU
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04107", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B15/01", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2307/412", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2311/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/202", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/047", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2311/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B15/01", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2311/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2311/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B15/01", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2307/202", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2311/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/047", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2307/412", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2311/20", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 74191069