PATENT DOCUMENT

Publication Number: US-10955947-B2
Application Number: US-201715493791-A
Country: US
Kind Code: B2

Title: RC tuning of touch electrode connections on a touch sensor panel

Abstract:
A touch sensor panel comprising a first touch node electrode of a plurality of touch node electrodes, the first touch node electrode coupled to a first sense connection comprising a first set of traces, the first sense connection configured to have a first resistance per unit length that varies along a length of the first sense connection, and a second touch node electrode of the plurality of touch node electrodes, the second touch node electrode coupled to a second sense connection comprising a second set of traces, the second sense connection configured to have a second resistance per unit length that varies along a length of the second sense connection differently than the first resistance per unit length varies along the length of the first sense connection. An effective resistance of the first sense connection and the second sense connection are equal.

Claims:
The invention claimed is: 
     
       1. A touch sensor panel comprising:
 a first touch node electrode of a plurality of touch node electrodes, the first touch node electrode coupled to a first sense connection comprising a first set of traces, the first sense connection configured to have a first resistance per unit length that varies along a length of the first sense connection; and 
 a second touch node electrode of the plurality of touch node electrodes, the second touch node electrode coupled to a second sense connection comprising a second set of traces, the second sense connection configured to have a second resistance per unit length that varies along a length of the second sense connection differently than the first resistance per unit length varies along the length of the first sense connection, 
 wherein a resistance of the first sense connection and the second sense connection are equal. 
 
     
     
       2. The touch sensor panel of  claim 1 , wherein the first touch node electrode and the second touch node electrode are both in either a row or a column of touch node electrodes on the touch sensor panel. 
     
     
       3. The touch sensor panel of  claim 1 , wherein the first sense connection comprises a first number of traces, and the second sense connection comprises a second number of traces, equal to the first number of traces. 
     
     
       4. The touch sensor panel of  claim 1 , wherein:
 the first sense connection comprises a first portion and a second portion configured to couple the first touch node electrode to sense circuitry, the first portion of the first sense connection comprising a first number of traces of the first set of traces coupled together, in parallel, and the second portion of the first sense connection comprising a second number of traces, different from the first number of traces, of the first set of traces coupled together, in parallel, and 
 the second sense connection comprises a first portion and a second portion configured to couple the second touch node electrode to the sense circuitry, the first portion of the second sense connection comprising a first number of traces of the second set of traces coupled together, in parallel, and the second portion of the second sense connection comprising a second number of traces, different from the first number of traces, of the second set of traces coupled together, in parallel. 
 
     
     
       5. The touch sensor panel of  claim 4 , wherein a length of the first portion of the first sense connection and a length of the first portion of the second sense connection are different. 
     
     
       6. The touch sensor panel of  claim 4 , wherein a length of the second portion of the first sense connection and a length of the second portion of the second sense connection are different. 
     
     
       7. The touch sensor panel of  claim 1 , wherein a capacitance of the first sense connection is equal to a capacitance of the second sense connection. 
     
     
       8. The touch sensor panel of  claim 1 , wherein a first respective portion of a first trace of the first set of traces is coupled to the second sense connection. 
     
     
       9. The touch sensor panel of  claim 8 , wherein:
 the first trace includes a first portion and a second portion, the second portion of the first trace comprising the first respective portion of the first trace, and the first portion of the first trace decoupled from the second portion of the first trace, 
 the first portion of the first trace is configured to couple the first touch node electrode to sense circuitry, and 
 the second portion of the first trace is configured to couple the second touch node electrode to the sense circuitry. 
 
     
     
       10. The touch sensor panel of  claim 9 , wherein the second portion of the first trace is coupled, in parallel, to at least a portion of the second set of traces in the second sense connection. 
     
     
       11. The touch sensor panel of  claim 9 , further comprising:
 a third touch node electrode of the plurality of touch node electrodes, the third touch node electrode coupled to a third sense connection comprising a third set of traces, 
 wherein a first respective portion of a second trace of the second set of traces, and a second respective portion of the first trace of the first set of traces are coupled to the third sense connection. 
 
     
     
       12. The touch sensor panel of  claim 11 , wherein:
 the first trace further includes a third portion, the third portion of the first trace comprising the second respective portion of the first trace, and the third portion of the first trace decoupled from the first and second portions of the first trace, 
 the second trace includes a first portion and a second portion, the second portion of the second trace comprising the first respective portion of the second trace, and the first portion of the second trace decoupled from the second portion of the second trace, 
 the first portion of the second trace is configured to couple the second touch node electrode to the sense circuitry, and 
 the second portion of the second trace and the third portion of the first trace are configured to couple the third touch node electrode to the sense circuitry. 
 
     
     
       13. The touch sensor panel of  claim 12 , wherein the second portion of the second trace and the third portion of the first trace are coupled, in parallel, to at least a portion of the third set of traces in the third sense connection. 
     
     
       14. The touch sensor panel of  claim 1 , further comprising:
 a third touch node electrode and a fourth touch node electrode in a column of touch node electrodes on the touch sensor panel, the column of touch node electrodes including the first touch node electrode and the second touch node electrode, the third touch node electrode coupled to a third sense connection comprising a third set of traces, and the fourth touch node electrode coupled to a fourth sense connection comprising a fourth set of traces, 
 wherein:
 the first touch node electrode is separated from the second touch node electrode by a first number of touch node electrodes, 
 the third touch node electrode is separated from the fourth touch node electrode by the first number of touch node electrodes, 
 a number of traces in the first set of traces equals a number of traces in the third set of traces, and 
 a number of traces in the second set of traces equals a number of traces in the fourth set of traces. 
 
 
     
     
       15. The touch sensor panel of  claim 14 , wherein the first touch node electrode is adjacent the third touch node electrode on the touch sensor panel, and the second touch node electrode is adjacent the fourth touch node electrode on the touch sensor panel. 
     
     
       16. The touch sensor panel of  claim 14 , wherein the first sense connection and the second sense connection are disposed in a first region of the touch sensor panel, and the third sense connection and the fourth sense connection are disposed in a second region of the touch sensor panel, other than the first region, adjacent the first region. 
     
     
       17. A method of fabricating a touch sensor panel, the method comprising:
 forming a first touch node electrode of a plurality of touch node electrodes, the first touch node electrode coupled to a first sense connection comprising a first set of traces, the first sense connection configured to have a first resistance per unit length that varies along a length of the first sense connection; and 
 forming a second touch node electrode of the plurality of touch node electrodes, the second touch node electrode coupled to a second sense connection comprising a second set of traces, the second sense connection configured to have a second resistance per unit length that varies along a length of the second sense connection differently than the first resistance per unit length varies along the length of the first sense connection, 
 wherein a resistance of the first sense connection and the second sense connection are equal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 62/368,855, filed Jul. 29, 2016, the entire disclosure of which is herein incorporated by reference in its entirety for all purposes. 
    
    
     FIELD OF THE DISCLOSURE 
     This relates generally to touch sensor panels, and more particularly to tuning loads presented by connections to touch electrodes on a touch sensor panel. 
     BACKGROUND OF THE DISCLOSURE 
     Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch screens, in particular, are becoming increasingly 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) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch and the position of the touch on the touch sensor panel, and the computing system can then interpret the touch in accordance with the display appearing at the time of the touch, and thereafter can perform one or more actions based on the touch. In the case of some touch sensing systems, a physical touch on the display is not needed to detect a touch. For example, in some capacitive-type touch sensing systems, fringing electrical fields used to detect touch can extend beyond the surface of the display, and objects approaching near the surface may be detected near the surface without actually touching the surface. 
     Capacitive touch sensor panels can be formed by a matrix of substantially transparent or non-transparent conductive plates made of materials such as Indium Tin Oxide (ITO). It is due in part to their substantial transparency that some capacitive touch sensor panels can be overlaid on a display to form a touch screen, as described above. Some touch screens can be formed by at least partially integrating touch sensing circuitry into a display pixel stackup (i.e., the stacked material layers forming the display pixels). 
     SUMMARY OF THE DISCLOSURE 
     Touch events can be sensed on the above touch sensor panels by detecting changes in the self-capacitance and/or mutual capacitance of the above conductive plates. In order to detect such changes, in some examples, the conductive plates can be coupled to sense circuitry using sense connections. It can be beneficial for the resistances and/or capacitances of these sense connections to be tuned such that transient operation of the sense connections (e.g., their bandwidths) can achieve desired parameters. The examples of the disclosure provide various techniques for tuning the resistances and/or capacitances of these sense connections. 
    
    
     
       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  is 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 and sense line and sensing circuit according to examples of the disclosure. 
         FIG. 4A  illustrates an example configuration in which common electrodes can form portions of the touch sensing circuitry of a touch sensing system according to examples of the disclosure. 
         FIG. 4B  illustrates an exemplary configuration for electrically connecting touch node electrodes in a touch screen to sense channels according to examples of the disclosure. 
         FIG. 5  illustrates an exemplary sense connection configuration in which longer sense connections can be made up of more traces than shorter sense connections according to examples of the disclosure. 
         FIG. 6A-6B  illustrate a “semi-RC matching” sense connection configuration and exemplary characteristics of a “semi-RC matching” sense connection configuration according to examples of the disclosure. 
         FIG. 7  illustrates a sense connection configuration in which excess portions of traces in a sense connection can be decoupled from the remainder of the traces in the sense connection to reduce a load presented to sense circuitry according to examples of the disclosure. 
         FIG. 8  illustrates a sense connection configuration in which cut portions of traces in a sense connection are re-used by other sense connections according to examples of the disclosure. 
         FIG. 9  illustrates a sense connection configuration in which cut portions of traces are used by multiple sense connections to reduce the resistances of those sense connections 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. Further, in the context of this disclosure, description of two quantities being “substantially equal” or “substantially the same” (or the like) is understood to include instances in which the quantities are equal and/or instances in which the quantities are within 15% of one another. 
     Some capacitive touch sensor panels can be formed by a matrix of substantially transparent or non-transparent conductive plates made of materials such as Indium Tin Oxide (ITO), and some touch screens can be formed by at least partially integrating touch sensing circuitry into a display pixel stackup (i.e., the stacked material layers forming the display pixels). Touch events can be sensed on the above touch sensor panels by detecting changes in the self-capacitance and/or mutual capacitance of the above conductive plates. In order to detect such changes, in some examples, the conductive plates can be coupled to sense circuitry using sense connections. It can be beneficial for the resistances and/or capacitances of these sense connections to be tuned such that transient operation of the sense connections (e.g., their bandwidths) can achieve desired parameters. The examples of the disclosure provide various techniques for tuning the resistances and/or capacitances of these sense connections. 
       FIGS. 1A-1D  illustrate example systems in which a touch screen according to examples of the disclosure may be implemented.  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 ). For example, a touch screen can include a plurality of individual touch node electrodes, 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. 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. 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 electrodes of a self-capacitance based touch system can be formed from rows and columns of conductive material, and changes in the self-capacitance to ground of the rows and columns can be detected, similar to above. In some examples, a touch screen can be multi-touch, single touch, projection scan, full-imaging multi-touch, capacitive touch, etc. 
     In some examples, touch screens  124 ,  126 ,  128  and  130  can be based on mutual capacitance. A mutual capacitance based touch system can include 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 be referred to as 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. 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. 
       FIG. 2  is 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 instead include a mutual capacitance touch screen, as described above, though the examples of the disclosure will be described assuming a self-capacitance touch screen is provided. 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, including a wearable device. 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  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 with touch screen  220  itself. 
     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 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. 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). 
     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 . 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  (Vac) 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  322  and sense  326  line 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 Vref. Operational amplifier  308  can drive its output to voltage Vo to keep Vin substantially equal to Vref, and can therefore maintain Vin 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 Vdetect. Vdetect 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 Vdetect 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, 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 an example configuration in which common electrodes  402  can form portions of the touch sensing circuitry of a touch sensing system—in some examples of this disclosure, the common electrodes can form touch node electrodes used to detect a touch image on touch screen  400 , as described above. Each common electrode  402  can include a plurality of display pixels  401 , and each display pixel  401  can include a portion of a common electrode  402 , which can be a circuit element of the display system circuitry in the display pixel stackup (i.e., the stacked material layers forming the display pixels) of the display pixels of some types of LCDs or other displays—in other words, the common electrodes can operate as part of the display system to display a display image on touch screen  400 . 
     In the example shown in  FIG. 4A , each common electrode  402  can serve as a multi-function circuit element that can operate as display circuitry of the display system of touch screen  400  and can also operate as touch sensing circuitry of the touch sensing system. Specifically, each common electrode  402  can operate as a common electrode of the display circuitry of the touch screen  400  (e.g., during a display phase), as described above, and can also operate as a touch node electrode of the touch sensing circuitry of the touch screen (e.g., during a touch sensing phase). Other circuit elements of touch screen  400  can also form part of the touch sensing circuitry. More specifically, in some examples, during the touch sensing phase, a gate line can be connected to a power supply, such as a charge pump, that can apply a voltage to maintain TFTs in display pixels included in a common electrode  402  in an “off” state. Stimulation signals can be applied to the common electrode  402 . Changes in the total self-capacitance of the common electrode  402  can be sensed through one or more operational amplifiers, as previously discussed. The changes in the total self-capacitance of the common electrode  402  can depend on the proximity of an object, such as finger  305 , to the common electrode. In this way, the measured changes in total self-capacitance of the common electrode  402  can provide an indication of touch on or near the touch screen. A mutual capacitance touch screen can similarly be implemented in which common electrodes can form portions of the touch sensing circuitry of the mutual capacitance touch screen. For example the common electrodes can form drive or sense lines used to detect a touch image on the touch screen, as described above. 
     In general, each of the touch sensing circuit elements may be either a multi-function circuit element that can form part of the touch sensing circuitry and can perform one or more other functions, such as forming part of the display circuitry, or may be a single-function circuit element that can operate as touch sensing circuitry only. Similarly, each of the display circuit elements may be either a multi-function circuit element that can operate as display circuitry and perform one or more other functions, such as operating as touch sensing circuitry, or may be a single-function circuit element that can operate as display circuitry only. Therefore, in some examples, some of the circuit elements in the display pixel stackups can be multi-function circuit elements and other circuit elements may be single-function circuit elements. In other examples, all of the circuit elements of the display pixel stackups may be single-function circuit elements. 
     In addition, although examples herein may describe the display circuitry as operating during a display phase, and describe the touch sensing circuitry as operating during a touch sensing phase, it should be understood that a display phase and a touch sensing phase may be operated at the same time, e.g., partially or completely overlapping, or the display phase and touch sensing phase may operate at different times. Also, although examples herein describe certain circuit elements as being multi-function and other circuit elements as being single-function, it should be understood that the circuit elements are not limited to the particular functionality in other examples. In other words, a circuit element that is described in one example herein as a single-function circuit element may be configured as a multi-function circuit element in other examples, and vice versa. 
     The common electrodes  402  (i.e., touch node electrodes) and display pixels  401  of  FIG. 4A  are shown as rectangular or square regions on touch screen  400 . However, it is understood that the common electrodes  402  and display pixels  401  are not limited to the shapes, orientations, and positions shown, but can include any suitable configurations according to examples of the disclosure. Further, the examples of the disclosure will be provided in the context of a touch screen, but it is understood that the examples of the disclosure can similarly be implemented in the context of a touch sensor panel. 
     As described above, the self-capacitance of each touch node electrode (e.g., touch node electrode  222 ) in the touch screen of the disclosure can be sensed to capture an image of touch across the touch screen. To allow for the sensing of the self-capacitance of individual touch node electrodes, it can be necessary to route one or more electrical connections between each of the touch node electrodes and the touch sensing circuitry (e.g., sense channels  208 ) of the touch screen. 
       FIG. 4B  illustrates an exemplary configuration for electrically connecting touch node electrodes  402  in touch screen  400  to sense channels  408  according to examples of the disclosure. In some examples, sense channels  408  can be located in a touch controller separate from the touch screen, but in some examples, the sense channels can be located on the touch screen. Touch screen  400  can include touch node electrodes  402 , as described above. Components of touch screen  400  other than touch node electrodes  402  are not illustrated for ease of description. Each of touch node electrodes  402  can be electrically connected to sense channels  408  through sense connections  404  and connection points  406 . In some examples, sense connections  404  can connect touch node electrodes  402  to a location on the touch screen (e.g., a flex circuit connection area) from which a separate connection (e.g., a flex circuit) can complete the connection to sense channels  408  (e.g., when the sense channels are located separate from touch screen  400 ). In some examples, sense connections  404  can connect touch node electrodes  402  directly to sense channels  408  (e.g., when the sense channels are located on touch screen  400 ). In some examples, connection points  406  can be vias when sense connections  404  and touch node electrodes  402  reside in different layers of touch screen  400  (e.g., when the sense connections reside underneath the touch node electrodes, or when the sense connections reside on top of the touch node electrodes); it is understood, however, that in some examples, the sense connections and the touch node electrodes can reside in the same layer of the touch screen, and the connection points can represent a location where the sense connections and the touch node electrodes connect. As discussed above, in some examples, connection points  406  can allow for an electrical connection between touch node electrodes  402  and sense connections  404  through one or more intervening layers that may exist between the touch node electrodes and the sense connections in touch screen  400 . 
     In connecting sense channels  408  and touch node electrodes  402 , it can be beneficial to tune the load (e.g., the resistance and/or the capacitance) that each sense connection  404  presents to the sense channels so that the transient operation of the sense connections can achieve desired parameters (e.g., an RC time constant for each sense connection can be set to a desired value). The examples of the disclosure are directed to various techniques for achieving the above load tuning. 
     Although the examples of the disclosure are presented in the context of connecting touch node electrodes to sense circuitry (e.g., sense channels), it is understood that the techniques described can be utilized in any context in which load tuning of connections between components can be desired (e.g., connecting mutual capacitance drive lines to drive circuitry). 
       FIG. 5  illustrates an exemplary sense connection configuration  500  in which longer sense connections  504  can be made up of more traces  510  than shorter sense connections according to examples of the disclosure. Touch node electrodes  502   a ,  502   b ,  502   c  and  502   d  (referred to collectively as touch node electrodes  502 ) can correspond to a column (or row) of touch node electrodes  402  on touch screen  400  in  FIGS. 4A-4B , for example. Touch node electrodes  502   a - d  are illustrated as being expanded in the horizontal dimension for ease of illustration. Each touch node electrode  502  can be coupled to sense circuitry  508  (e.g., sense channels  208 ) through respective connection points and sense connections—e.g., touch node electrode  502   a  can be coupled to the sense circuitry through connection point  506   a  and sense connection  504   a . The remaining touch node electrodes  502  can be similarly coupled to sense circuitry  508 , as illustrated. Sense connections  504   a - d  (referred to collectively as sense connections  504 ) can correspond to sense connections  404  in  FIGS. 4A-4B , and connection points  506   a - d  (referred to collectively as connection points  506 ) can correspond to connection points  406  in  FIGS. 4A-4B , for example. 
     Because sense connections  504  that are coupled to touch node electrodes  502  that are towards the top of the touch screen (e.g., relatively far away from sense circuitry  508 , such as touch node electrode  502   a ) may be longer than sense connections coupled to touch node electrodes that are towards the bottom of the touch screen (e.g., relatively close to the sense circuitry, such as touch node electrode  502   d ), it can be beneficial to reduce the resistance per unit length of the sense connections coupled to the touch node electrodes towards the top of the touch screen with respect to the sense connections coupled to the touch node electrodes towards the bottom of the touch screen, so that the total effective resistances of the sense connections do not differ greatly (e.g., do not differ by more than a threshold resistance). In some examples, to achieve the above, sense connections  504  can be made up of one or more traces  510 . For example, sense connection  504   a  can be made up of traces  510   a ,  510   b ,  510   c  and  510   d  connecting, in parallel, a given sense channel (e.g., sensing circuit  314  in  FIG. 3A ) in sense circuitry  508  to touch node electrode  502   a . Traces  510   a ,  510   b ,  510   c  and  510   d  can be electrically connected together at touch node electrode  502  (e.g., at connection point  506   a ) using bridge  512   a . Further, in some examples, traces  510   a ,  510   b ,  510   c  and  510   d  can extend to the top of touch screen  500 , as illustrated. Traces  510   a ,  510   b ,  510   c  and  510   d  and/or bridge  512   a  can be composed of any electrically conductive material, such as indium tin oxide (ITO). Further, in some examples, traces  510   a ,  510   b ,  510   c  and  510   d  (and other traces  510 ) can be routed underneath data lines in the touch screen, and bridge  512   a  (and other bridges  512 ) can be routed underneath gate lines in the touch screen so as to reduce the impact of the traces and/or bridges on the aperture ratio of the touch screen. The effective resistance that sense connection  504   a  can present to sense circuitry  508  can be the resistance of traces  510   a ,  510   b ,  510   c  and  510   d  in parallel along a length from the sense circuitry to touch node electrode  502   a  (or connection point  506   a ). The effective capacitance that sense connection  504   a  can present to sense circuitry  508  can be, substantially, the sum of the capacitances seen by each of traces  510   a ,  510   b ,  510   c  and  510   d  (e.g., capacitances between the traces and other touch screen components) along a total length of the traces (e.g., 4C T , if C T  corresponds to the capacitance seen by a single trace  510   a, b, c  or  d ). Further, in some examples, touch node electrode  502   a  can also present a capacitance to sense circuitry  508 , via sense connection  504   a , which can be included in the effective capacitance that sense connection  504   a  can present to the sense circuitry. 
     Sense connections  504   b ,  504   c  and  504   d  can be similar in configuration to sense connection  504   a , except that sense connections  504   b ,  504   c  and  504   d  can be made up of fewer traces  510  than sense connection  504   a , because touch node electrodes  502   b ,  502   c  and  502   d  can be closer to sense circuitry  508  than is touch node electrode  502   a , and thus fewer traces  510  may be required to achieve a desired effective resistance for sense connections  504   b ,  504   c  and  504   d . For example, sense connection  504   b , which can be made up of traces  510   e ,  510   f  and  510   g , can connect, in parallel, a given sense channel (e.g., sensing circuit  314  in  FIG. 3A ) in sense circuitry  508  to touch node electrode  502   b . Traces  510   e ,  510   f  and  510   g  can be electrically connected together at touch node electrode  502   b  (e.g., at connection point  506   b ) using bridge  512   b . Further, in some examples, traces  510   e ,  510   f  and  510   g  can extend to the top of touch screen  500 , as illustrated. The effective resistance that sense connection  504   b  can present to sense circuitry  508  can be the resistance of traces  510   e ,  510   f  and  510   g  in parallel along a length—less than the length from the sense circuitry to touch node electrode  502   a  described with reference to sense connection  504   a —from the sense circuitry to touch node electrode  502   b  (or connection point  506   b ). The effective capacitance that sense connection  504   b  can present to sense circuitry  508  can be the sum of the capacitances seen by each of traces  510   e ,  510   f  and  510   g  along a total length of the traces (e.g., 3C T , if C T  corresponds to the capacitance seen by a single trace  510   a, b, c  or  d ). Further, in some examples, touch node electrode  502   b  can also present a capacitance to sense circuitry  508 , via sense connection  504   b , which can be included in the effective capacitance that sense connection  504   b  can present to the sense circuitry. 
     Sense connections  504   c  and  504   d  can analogously present effective resistances and capacitances (2C T  and C T , respectively) to sense circuitry  508  via traces  510   h  and  510   i  (corresponding to sense connection  504   c ) and trace  510   j  (corresponding to sense connection  504   d ). As shown above, increasing the number of traces  510  in a sense connection  504  can reduce the resistance of the sense connection, but can also increase the capacitance of the sense connection. In some examples, the number of traces in various sense connections  504  can be adjusted until the RC time constant of the worst-performing sense connection-touch node electrode pair is minimized. 
     As described above, sense connection configuration  500  of  FIG. 5 , in which sense connections  504  for touch node electrodes  502  further away from sense circuitry  508  can include more traces connected in parallel than sense connections for touch node electrodes closer to the sense circuitry, can work to reduce the effective resistances of longer sense connections, and thus improve the RC time constants (and correspondingly, the bandwidths) of those sense connections. However, in some examples, additional design flexibility may be desired. Specifically, the resistances and/or capacitances that sense connections present to the sense circuitry of the touch screen of the disclosure can be tuned such that the RC time constants (and thus bandwidths) of sense connections that are made up of equal numbers of traces can substantially match, despite those sense connections having different lengths (e.g., due to being electrically connected to touch node electrodes that are disposed at different distances from the sense circuitry of the touch screen). This can be accomplished by independently varying the resistance per unit length of the sense connections such that the sense connections have substantially equal RC time constants (and thus bandwidth), as will be described in more detail below. Additionally, sense connections that are made up of different numbers of traces can be similarly configured to have RC time constants (and thus bandwidths) that substantially match, or deviate less than a threshold from, the RC time constants of other sense connections that are made up of different numbers of traces. Such a sense connection scheme can be referred to as a “semi-RC matching” scheme, because while the RC time constants of sense connections having equal numbers of traces can be matched, the RC time constants of sense connections having different numbers of traces may not be. 
       FIG. 6A  illustrates a “semi-RC matching” sense connection configuration  600  according to examples of the disclosure. Sense connection configuration  600  can be similar to sense connection configuration  500  in  FIG. 5 , except as described below. Touch node electrode  602   a  can be coupled to sense circuitry  608  via sense connection  604   a , touch node electrode  602   b  can be coupled to the sense circuitry via sense connection  604   b , touch node electrode  602   c  can be coupled to the sense circuitry via sense connection  604   c , and touch node electrode  602   d  can be coupled to the sense circuitry via sense connection  604   d . Touch node electrodes  602   e  and  602   f  can be disposed between touch node electrode  602   d  and sense circuitry  608  on the touch screen, and can also be coupled to the sense circuitry, though via sense connections not illustrated in  FIG. 6A . 
     As previously described, the effective resistances of two or more sense connections on the touch screen can be substantially matched by varying the resistance per unit length of the sense connections such that the sense connections have substantially equal RC time constants (and thus bandwidth). Specifically, in  FIG. 6A , two or more sense connections on the touch screen can be made up of equal numbers of traces. For example, sense connection  604   a  can be made up of traces  610   a ,  610   b  and  610   c , sense connection  604   b  can be made up of traces  610   d ,  610   e  and  610   f , and sense connection  604   c  can be made up of traces  610   g ,  610   h  and  610   i . The capacitances presented to sense circuitry  608  by sense connections  604   a ,  604   b  and  604   c  can be substantially equal (e.g., 3C T , if C T  corresponds to the capacitance presented by a single trace  610   a, b, c, d, e, f, g, h  or  i ), because traces  610  in those sense connections can all have total lengths that are substantially equal (e.g., from sense circuitry  608  up to/through touch node electrode  602   a , as illustrated in  FIG. 6A ). The effective resistances of sense connections  604   a ,  604   b  and  604   c  can also be made substantially equal, as will be described below, to make the RC time constants (and thus the bandwidths) of sense connections  604   a ,  604   b  and  604   c  substantially equal. 
     Specifically, sense connections  604   a ,  604   b  and  604   c  can comprise two or more portions, each portion including the same number of traces  610 , but each portion having different numbers of traces that are within the signal path between the corresponding touch node electrodes  602   a ,  602   b  and  602   c , respectively, and sense circuitry  608 ; thus, the resistance per unit length of these sense connections can vary along the lengths of the sense connections. For example, sense connection  604   a  can include a first portion  650   a  between sense circuitry  608  and bridge  612   a  (which can electrically couple together traces  610   a ,  610   b  and  610   c ), and a second portion  650   b  between bridge  612   a  and connection point  606   a  connecting to touch node electrode  602   a . The first portion  650   a  of sense connection  604   a  can include the same number of traces  610  as the second portion  650   b  of the sense connection. However, the first portion  650   a  of sense connection  604   a  can have a different number of traces  610  that are within the signal path between touch node electrode  602   a  and sense circuitry  608  than the second portion  650   b  of sense connection  604   a . Specifically, in portion  650   a  of sense connection  604   a , all three of traces  610   a ,  610   b  and  610   c  can be within the signal path between touch node electrode  602   a  and sense circuitry  608  (e.g., because all three of traces  610   a - c  can be electrically connected in parallel between touch node electrode  602   a  and sense circuitry  608 ). In contrast, in portion  650   b  of sense connection  604   a , only trace  610   c  can be within the signal path between touch node electrode  602   a  and sense circuitry  608 , because only trace  610   c  may carry a signal (e.g., a touch signal) from touch node electrode  602   a  to sense circuitry  608 —traces  610   a  and  610   b  in portion  650   b  of sense connection  604   a  may be electrically connected to touch node electrode  602   a , but may be open-circuited in portion  650   b , and thus may not carry the signal from touch node electrode  602   a  to sense circuitry  608 . As such, the resistance per unit length of sense connection  604   a  in portion  650   a  (e.g., the equivalent resistance per unit length of three traces  610  connected in parallel) can be lower than the resistance per unit length of sense connection  604   a  in portion  650   b  (e.g., the equivalent resistance per unit length of one trace  610   c ). 
     By controlling the numbers of traces in a sense connection that are within the signal path between a touch node electrode and the sense circuitry, as well as the lengths of the various portions of the sense connection, the effective resistance of the sense connection can be set as desired (e.g., can be made substantially equal to other sense connections). Further, the capacitances of the various sense connections that have the same number of traces can remain substantially equal regardless of the resistance set above, because the capacitances of the sense connections can be substantially determined by the number of traces making up the sense connections, which can be constant. For example, sense connection  604   b , like sense connection  604   a , can include three traces  610   d - f ; thus, the capacitance presented by sense connection  604   b  to sense circuitry  608  can be substantially equal to the capacitance presented by sense connection  604   a  to sense circuitry  608 . Similar to sense connection  604   a , portion  652   a  of sense connection  604   b  can include traces  610   d ,  610   e  and  610   f  connected in parallel (via bridge  612   b ), and portion  652   b  of sense connection  604   b  can include trace  610   f  connected to connection point  606   b  at touch node electrode  602   b . The lengths of portions  652   a  and  652   b  of sense connection  604   b  can be adjusted (e.g., based on the placement of bridge  612   b ) so that the total effective resistance of sense connection  604   b  is substantially equal to the total effective resistance of sense connection  604   a . For example, in  FIG. 6A , portion  652   a  of sense connection  604   b  can be shorter in length than portion  650   a  of sense connection  604   a , and portion  652   b  of sense connection  604   b  can be longer in length than portion  650   b  of sense connection  604   a . Because the capacitances and effective resistances of sense connections  604   a  and  604   b  can be substantially equal, their RC time constants (and thus their operating bandwidths) can be substantially equal. 
     Finally, sense connection  604   c  can similarly have substantially the same capacitance as sense connections  604   a  and  604   b . The effective resistance of sense connection  604   c  can be set, as described above, to be substantially equal to the effective resistances of sense connections  604   a  and  604   b . Specifically, sense connection  604   c  can include portion  654   a  having traces  610   g - i  connected in parallel (via bridge  612   c ), and portion  654   b  in which traces  610   h - i  can be connected in parallel and to connection point  606   c . Thus, portion  654   b  of sense connection  604   c  can include two traces connected in parallel to connection point  606   c , whereas portion  652   b  of sense connection  604   b  and portion  650   b  of sense connection  604   a  can include a single trace connected to connection points  606   b  and  606   a , respectively. The lengths of portions  654   a  and  654   b  of sense connection  604   c  can be adjusted (e.g., based on the placement of bridge  612   c ) so that the total effective resistance of sense connection  604   c  is substantially equal to the total effective resistances of sense connections  604   a  and  604   b . For example, in  FIG. 6A , portion  654   a  of sense connection  604   c  can be shorter in length than portions  650   a  of sense connection  604   a  and  652   a  of sense connection  604   b , and portion  654   b  of sense connection  604   c  can be longer in length that portions  650   b  of sense connection  604   a  and  652   b  of sense connection  604   b . Because the capacitances and effective resistances of sense connections  604   a ,  604   b  and  604   c  can be substantially equal, their RC time constants (and thus their operating bandwidths) can be substantially equal. 
     It should be noted that as is illustrated in  FIG. 6A , the number of traces within the signal path of a given sense connection can vary differently in different sense connections, even though those sense connections can include the same number of total traces. For example, sense connections  604 A,  604 B and  604 C can all include the same number of total traces (e.g., three traces). However, in sense connections  604 A and  604 B, the number of traces within the signal paths in those sense connections can vary from three traces in the respective lower portions of those sense connections (e.g., portions  650 A and  652 A) to one trace in the respective upper portions of those sense connections (e.g., portions  650 B and  652 B), while the number of traces within the signal path of sense connection  604 C can vary from three traces in the lower portion of that sense connection (e.g., portion  654 A) to two traces in the upper portion of that sense connection (e.g., portion  654 B). Other similar variations are also possible (e.g., some signal paths varying from four traces to one trace, from four traces to two traces, and from four traces to three traces). 
     Sense connection  604   d  can include traces  610   j - k —fewer traces than in sense connections  604   a - c . Thus, the capacitance of sense connection  604   d  can differ substantially from the capacitances of sense connections  604   a - c . However, the effective resistance of sense connection  604   d  can be set, as described above, such that the RC time constant (and thus the bandwidth) of sense connection  604   d  is substantially equal to, or within a threshold of, the RC time constants of sense connections  604   a - c . Similar to sense connections  604   a - 604   c , sense connection  604   d  can include portions with different numbers of traces within the signal path from touch node electrode  602   d  to sense circuitry  608 . Specifically, portion  656   a  of sense connection  604   d  can include traces  610   j - k  connected in parallel (via bridge  612   d ), and portion  656   b  of sense connection  604   d  can include trace  610   k  connected to connection point  606   d . The lengths of portions  656   a  and  656   b  of sense connection  604   d  can be adjusted (e.g., based on the placement of bridge  612   d ), as described above, to achieve an appropriate effective resistance for sense connection  606   d  (e.g., to substantially match the effective resistances of other sense connections on the touch screen that are made up of two traces (not illustrated)). 
     In some examples, the portions of traces  610  that are not within the signal paths from a touch node electrode  602  to sense circuitry  608  can be decoupled (e.g., electrically isolated) from the portions of traces  610  that are within the signal paths from a touch node electrode  602  to sense circuitry  608 , similar to as described in  FIG. 7 . For example, in portion  652 B of sense connection  604 B, traces  610 D and  610 E can be decoupled from (e.g., cut from) traces  610  D and  610 E in portion  652 A of sense connection  604 B. Similarly, trace  610 F above portion  652 B of sense connection  604 B can be decoupled from (e.g., cut from) trace  610 F in portion  652 B of sense connection  604 B. In some examples, these decoupled portions of traces  610  can be floating, or can be coupled to a power source (e.g., AC or DC power source), as shown in  FIG. 7 . Further, in some examples, these decoupled portions of traces  610  can be coupled to neighboring sense connections to reduce the resistances of those sense connections, as shown in  FIGS. 8-9 . By decoupling these portions of traces that are not within the signal paths from a touch node electrode  602  to sense circuitry  608 , the capacitive load presented to the sense circuitry  608  can be reduced. As an alternative, in some examples, the portions of traces  610  that are not within the signal paths from a touch node electrode  602  to sense circuitry  608 , instead of being decoupled as described above, can be nonexistent. That is to say that in some examples, traces may end at bridges  612  if the extensions of those traces past bridges  612  would not be within the signal paths of their corresponding sense connections. For example, trace  610 D in sense connection  604 B can end at bridge  612 B such that trace  610 D may not extend into or above region  652 B of sense connection  604 B. 
     Further, in some examples, the signal path between sense circuitry  608  and a given touch node electrode  602  may not extend above that given touch node electrode  602  (e.g., the signal path may be wholly contained within the area of the given touch node electrode  602  and/or between the given touch node electrode  602  and sense circuitry  608 ). For example, in sense connection  604 B, the signal path between touch node electrode  602 B and sense circuitry may not extend above touch node electrode  602 B (e.g., may not extend into the gap between touch node electrodes  602 A and  602 B, or into touch node electrode  602 A), and may be wholly contained within the area of touch node electrode  602 B and/or between touch node electrode  602 B and sense circuitry  608  on the touch sensor panel. 
       FIG. 6B  illustrates various characteristics of an example “semi-RC matching” sense connection configuration according to the examples of  FIG. 6A  in which the maximum number of traces in a given sense connection is five, according to examples of the disclosure. Plot  652  can indicate the number of traces that are within the signal paths of the sense connections after the bridge in those sense connections (e.g., the number of traces in portions  650 B,  652 B,  654 B,  656 B of sense connections  604 ), plot  654  can indicate the lengths of the signal paths of the sense connections after the bridge in those sense connections (e.g., the lengths of portions  650 B,  652 B,  654 B,  656 B of sense connections  604 ), plot  656  can indicate the RC time constants of the sense connections, and plot  658  can indicate the 1 dB cutoff frequency (Hz) of the sense connections. It is understood that plots  652 ,  654 ,  656  and  658  provide example details of a “semi-RC matching” sense connection configuration, but that other “semi-RC matching” sense connection configurations according to the examples provided herein are within the scope of this disclosure. 
     Plots  652 ,  654 ,  656  and  658  can correspond to sense connections for a column of touch node electrodes on a touch sensor panel (or a row of touch node electrodes on the touch sensor panel, or any other arrangement of touch node electrodes on the touch sensor panel). The horizontal axes of each of plots  652 ,  654 ,  656  and  658  can correspond to the position of each touch node electrode on the touch sensor panel corresponding to those sense connections. For example, the left-most unit on the horizontal axis can correspond to a sense connection for a touch node electrode that is closest to the sense circuitry (e.g., the lower-most touch node electrode in the column of touch node electrodes in a circumstance in which the sense circuitry is located at or close to the bottoms of the columns of touch node electrodes, as in  FIGS. 5-9 ), and the right-most unit on the horizontal axis can correspond to a sense connection for a touch node electrode that is furthest from the sense circuitry (e.g., the upper-most touch node electrode in the column of touch node electrodes in a circumstance in which the sense circuitry is located at or close to the bottoms of the columns of touch node electrodes, as in  FIGS. 5-9 ). 
     The sense connections represented in  FIG. 6B  can include five sets of sense connections: set  603 A (sense connections having one trace, and corresponding to the 11 touch node electrodes closest to the sense circuitry), set  603 B (sense connections having two traces, and corresponding to the next 11 touch node electrodes closest to the sense circuitry), set  603 C (sense connections having three traces, and corresponding to the next eight touch node electrodes closest to the sense circuitry), set  603 D (sense connections having four traces, and corresponding to the next ten touch node electrodes closest to the sense circuitry) and set  603 E (sense connections having five traces, and corresponding to the eight touch node electrodes furthest from the sense circuitry). 
     As mentioned above, sense connections in set  603 E can include five traces. As shown in plot  652 , the sense connection corresponding to the touch node electrode furthest from the sense circuitry can include five sense connections within its signal path the entire distance from the sense circuitry to the touch node electrode. The other sense connections in set  603 E can include a bridge (e.g., bridges  612  in  FIG. 6A ) at which the number of sense connections within their signal paths can be reduced from five to four. The lengths of the upper portions of those sense connections (e.g., portions  650 B,  652 B,  654 B,  656 B in  FIG. 6A ) can gradually increase, as shown in plot  654 , as the sense connections correspond to touch node electrodes closer to the sense circuitry (moving leftward in plots  652  and  654 ). As previously mentioned, sense connections in set  603 D can include four traces. As shown in plot  652 , the sense connection in set  603 D corresponding to the touch node electrode furthest from the sense circuitry can include four sense connections within its signal path the entire distance from the sense circuitry to the touch node electrode. The other sense connections in set  603 D can include a bridge (e.g., bridges  612  in  FIG. 6A ) at which the number of sense connections within their signal paths can be reduced from four to three. The lengths of the upper portions of those sense connections (e.g., portions  650 B,  652 B,  654 B,  656 B in  FIG. 6A ) can gradually increase (in some examples, more slowly than do the lengths of the upper portions of the sense connections in set  603 E), as shown in plot  654 , as the sense connections correspond to touch node electrodes closer to the sense circuitry (moving leftward in plots  652  and  654 ). 
     As previously mentioned, sense connections in set  603 C can include three traces. As shown in plot  652 , the sense connection in set  603 C corresponding to the touch node electrode furthest from the sense circuitry can include three sense connections within its signal path the entire distance from the sense circuitry to the touch node electrode. The other sense connections in set  603 C can include a bridge (e.g., bridges  612  in  FIG. 6A ) at which the number of sense connections within their signal paths can be reduced from three to two. The lengths of the upper portions of those sense connections (e.g., portions  650 B,  652 B,  654 B,  656 B in  FIG. 6A ) can gradually increase (in some examples, more slowly than do the lengths of the upper portions of the sense connections in set  603 D), as shown in plot  654 , as the sense connections correspond to touch node electrodes closer to the sense circuitry (moving leftward in plots  652  and  654 ). As previously mentioned, sense connections in set  603 B can include two traces. As shown in plot  652 , the sense connection in set  603 B corresponding to the touch node electrode furthest from the sense circuitry can include two sense connections within its signal path the entire distance from the sense circuitry to the touch node electrode. The other sense connections in set  603 B can include a bridge (e.g., bridges  612  in  FIG. 6A ) at which the number of sense connections within their signal paths can be reduced from two to one. The lengths of the upper portions of those sense connections (e.g., portions  650 B,  652 B,  654 B,  656 B in  FIG. 6A ) can gradually increase (in some examples, more slowly than do the lengths of the upper portions of the sense connections in set  603 C), as shown in plot  654 , as the sense connections correspond to touch node electrodes closer to the sense circuitry (moving leftward in plots  652  and  654 ). Finally, as previously mentioned, sense connections in set  603 A can include a single trace. As shown in plot  652 , the sense connections in set  603 A can include a single trace within their signal paths the entire distance from the sense circuitry to the touch node electrodes. The lengths of the sense connections can gradually decrease as the sense connections correspond to touch node electrodes closer to the sense circuitry (moving leftward in plots  652  and  654 ). 
     Focusing on plot  656 , sense connections in set  603 E can have the same (e.g., within 10% of each other) RC time constants, sense connections in set  603 D can have the same (e.g., within 10% of each other) RC time constants (in some examples, lower than the RC time constants of the sense connections in set  603 E), sense connections in set  603 C can have the same (e.g., within 10% of each other) RC time constants (in some examples, lower than the RC time constants of the sense connections in set  603 D), and sense connections in set  603 B can have the same (e.g., within 10% of each other) RC time constants (in some examples, lower than the RC time constants of the sense connections in set  603 C). Sense connections in set  603 A can have lower RC time constants than sense connections in set  603 B. However, the RC time constants of sense connections in set  603 A can gradually increase as the sense connections correspond to touch node electrodes further from the sense circuitry (moving rightward in plot  656 ). 
     Finally, focusing on plot  658 , the performance of the lowest-performing sense connection in each set of sense connections can be the same (e.g., within 10% of one another). For example, the 1 dB cutoff frequency of the lowest-performing sense connection in sets  603 A,  603 B,  603 C,  603 D and  603 E can be the same (e.g., within 10% of one another). In some examples, the lowest-performing sense connection in each set of sense connections can be the sense connection that corresponds to the touch node electrode furthest from the sense circuitry in that set (e.g., the right-most sense connection in each set in plot  658 ). The 1 dB cutoff frequencies of the other sense connections in each set can gradually increase as the sense connections correspond to touch node electrodes closer to the sense circuitry (moving leftward in plot  658 ). In some examples, the rate of increase of the 1 dB cutoff frequencies of the sense connections in set  603 A can be greater than the rates of increase of the 1 dB cutoff frequencies of the sense connections in sets  603 B,  603 C,  603 D and  603 E. Thus, as shown in plots  652 ,  654 ,  656  and  658 , in some examples, the sense connections for a given column (or other collection) of touch node electrodes can transition from including five traces (set  603 E) to including four traces (set  603 D), from including four traces (set  603 D) to including three traces (set  603 C), from including three traces (set  603 C) to including two traces (set  603 B), and from including two traces (set  603 B) to including one trace ( 603 A) such that the lowest-performing sense connection in each set can have the same (e.g., within 10% of one another) bandwidth. 
     It is understood that in some examples, one or more sense connections in set  603 A can have physical features that vary (e.g., increase) the resistances of select one(s) of the sense connections such that the RC time constants of the sense connections in set  603 A are the same (e.g., within 10% of one another). For example, the trace forming the left-most sense connection in set  603 A (corresponding to the sense connection for the touch node electrode closest to the sense circuitry) can be extended or lengthened (e.g., can extend up past the touch node electrode to which it corresponds, and can loop back down to finally couple to the touch node electrode, can include a zigzag pattern, etc.) to increase its resistance such that the RC time constant of that sense connection is the same as (e.g., within 10% of) the RC time constant of the right-most sense connection in set  603 A (corresponding to the sense connection for the touch node electrode furthest from the sense circuitry for that set of sense connections). The resistances of other sense connections in set  603 A can similarly be increased such that the RC time constants of those sense connections are also the same as (e.g., within 10% of) the RC time constant of the right-most sense connection in set  603 A. In this way, sense connections in set  603 A can have substantially uniform RC time constants, similar to the RC time constants of sense connections in sets  603 B,  603 C,  603 D and  603 E. 
     Further, such trace- and/or sense connection-extension as discussed above (e.g., sense connection routing from the sense circuitry to the touch node electrodes that is indirect, such as by looping up past the touch node electrodes and then back down to couple to the touch node electrodes, zigzag routing of the traces/sense connections, etc.) can, more generally, be implemented in any of the traces/sense connections in sets  603 A,  603 B,  603 C,  603 D and  603 E. In other words, sense connections in sets  603 A,  603 B,  603 C,  603 D and/or  603 E need not be routed to their corresponding touch node electrodes in the most direct (e.g., shortest, straight line, etc.) manner Rather, those sense connections can be routed to their corresponding touch node electrodes in a more indirect manner while still exhibiting the characteristics of the sense connections described with reference to  FIGS. 6A-6B . As such, in such circumstances, the “distance from the sense circuitry” reflected in  FIG. 6B  can be a function of or correspond to the lengths of the traces/sense connections of touch node electrodes rather than purely to the distances of those touch node electrodes from the sense circuitry. Further, more generally, traces/sense connections illustrated in and described with reference to  FIGS. 5, 7 and 8-9  can similarly be routed in a more indirect manner while still exhibiting the described characteristics of those routing schemes. 
       FIG. 7  illustrates sense connection configuration  700  in which excess portions of traces in a sense connection can be decoupled from the remainder of the traces in the sense connection to reduce a load presented to sense circuitry  708  according to examples of the disclosure. Sense connection configuration  700  can be similar to sense connection configuration  500  in  FIG. 5 , except as described below. In  FIG. 7 , touch node electrode  702   a  can be coupled to sense circuitry  708  via sense connection  704   a , which, in the example illustrated, can be made up of one trace  710   a , though the principles described with reference to  FIG. 7  can be applied to sense connections having more than one trace in accordance with the examples of the disclosure. Trace  710   a  can be continuous from sense circuitry  708  until it couples to touch node electrode  702   a  at connection point  706   a . In order to reduce the capacitive load presented to sense circuitry  708  by sense connection  704   a , trace  710   a  can include break  714   a , which can electrically decouple portion  750   a  of trace  710   a  below connection point  706   a  from portion  750   b  of trace  710   a  above connection point  706   a  (e.g., the portion of trace  710   a  that is not within the signal path between touch node electrode  702   a  and sense circuitry  708 ). In this way, the capacitive load presented by portion  750   b  of trace  710   a  above connection point  706   a  can be isolated from sense circuitry  708 . In some examples, portion  750   b  of trace  710   a  can be electrically coupled to a separate voltage source  712 , which can apply a DC or AC potential to portion  750   b  of trace  710   a  (in some examples, the same potential as is being applied to portion  750   a  of trace  710   a ), so that portion  750   b  of trace  710   a  is not left floating as a potential source of parasitic capacitance. In some examples, however, portion  750   b  of trace  710   a  can be left electrically floating on the touch screen. 
     Traces  710  in sense connections  704   b ,  704   c  and  704   d  can similarly include breaks  714   b ,  714   c  and  714   d  for electrically decoupling portions  752   a ,  754   a  and  756   a  of traces  710   b ,  710   c  and  710   d , respectively, within the signal paths between touch node electrodes  702  and sense circuitry  708  from portions  752   b ,  754   b  and  756   b  of traces  710   b ,  710   c  and  710   d , respectively, not within the signal paths between touch node electrodes  702  and sense circuitry  708 , as illustrated in  FIG. 7 . Additionally, portions  752   b ,  754   b  and  756   b  of traces  710   b ,  710   c  and  710   d , respectively, can be electrically coupled to voltage source  712 , similar to portion  750   b  of trace  710   a , though in some examples, portions  752   b ,  754   b  and  756   b  can be left electrically floating on the touch screen. In this way, the capacitive load presented by each sense connection  704  to sense circuitry  708  can be reduced, which can reduce the RC time constants (and thus increase the operating bandwidths) of the sense connections. For ease of description, portions  750   b ,  752   b ,  754   b  and  756   b  of traces  710   a ,  710   b ,  710   c  and  710   d  can be referred to as the “cut portions” of traces  710   a ,  710   b ,  710   c  and  710   d . Further, it is understood that while the example of  FIG. 7  includes sense connections  704  each having a single trace  710 , sense connections with more than one trace can similarly include breaks to decouple portions of the traces not within the signal paths between corresponding touch node electrodes  702  and sense circuitry  708  from the sense circuitry. 
     In some examples, the cut portions of traces above connection points to corresponding touch node electrodes can be utilized by sense connections of other touch node electrodes to reduce the resistances of those sense connections.  FIG. 8  illustrates a sense connection configuration  800  in which cut portions of traces in a sense connection are re-used by other sense connections according to examples of the disclosure.  FIG. 8  illustrates three touch node electrodes  802   a ,  802   b  and  802   c . Among touch node electrodes  802   a - c , touch node electrode  802   a  can be furthest from sense circuitry  808 , touch node electrode  802   c  can be closest to sense circuitry  808 , and touch node electrode  802   b  can be between touch node electrode  802   a  and touch node electrode  802   c , as illustrated; in some examples, touch node electrode  802   b  can be adjacent touch node electrode  802   c  on the touch screen, though this need not be the case. In some examples, touch node electrode  802   a  can be adjacent touch node electrode  802   b  on the touch screen, though in  FIG. 8 , touch node electrode  802   a  and touch node electrode  802   b  can be separated by one or more other touch node electrodes (not illustrated). 
     Similar to as described with reference to  FIG. 7 , one or more of the traces in sense connections in  FIG. 8  can include breaks after the traces are coupled to their corresponding touch node electrodes. For example, touch node electrode  802   b  can be coupled to sense circuitry  808  via sense connection  804   b , which can include trace  810   a . Trace  810   a  can electrically couple sense circuitry  808  to touch node electrode  802   b  at connection point  806   b . After connection point  806   b , trace  810   a  can include break  814   b  for decoupling portion  850   b  of trace  810   a  from portion  850   a  of trace  810   a  below connection point  806   b  (thus reducing the load presented by trace  810   a  to sense circuitry  808 ). Similarly, trace  810   f  in sense connection  804   c  can include break  814   c  after connection point  806   c  to reduce the load presented by trace  810   f  to sense circuitry  808 . 
     In contrast to  FIG. 7 , in the configuration of  FIG. 8 , the portions of traces that are electrically decoupled from traces connected to sense circuitry  808  (e.g., portions  850   b  and  852   b  of traces  810   a  and  810   f , respectively) can be electrically coupled to the traces of a sense connection of a touch node electrode that is further away from sense circuitry  808  to reduce the resistance of that sense connection. In other words, the cut portions of traces  810   a  and  810   f  can be re-used by sense connections of other touch node electrodes (e.g., touch node electrodes further away from sense circuitry  808 ) to reduce their resistance by reducing their resistance per unit length at one or more locations along the lengths of the sense connections. For example, in  FIG. 8 , sense connection  804   a  can couple touch node electrode  802   a  to sense circuitry  808 . Sense connection  804   a  can include traces  810   b ,  810   c ,  810   d  and  810   e  electrically connected in parallel, which can all be electrically connected to connection point  806   a  at touch node electrode  802   a . To reduce the resistance of sense connection  804   a , portion  850   b  of trace  810   a  can also be electrically connected, in parallel, to traces  810   b ,  810   c ,  810   d  and  810   e  in sense connection  804   a  (e.g., via bridge  812   a ), which can reduce the resistance per unit length of sense connection  804   a  along the length of portion  850   b  of trace  810   a . Additionally or alternatively, portion  852   b  of trace  810   f  can similarly be electrically connected, in parallel, to traces  810   b ,  810   c ,  810   d  and  810   e  in sense connection  804   a  (e.g., via bridge  812   b ), which can reduce the resistance per unit length of sense connection  804   a  along the length of portion  852   b  of trace  810   f  (in some examples, different from the length of portion  850   b  of trace  810   a ). In this way, portions  850   b  of trace  810   a  and  852   b  of trace  810   f  can be used to reduce the resistance of sense connection  804   a . It is understood that while the example of  FIG. 8  includes re-using cut portions of sense connections  804  having a single trace  810 , cut portions of sense connections with more than one trace can similarly be re-used by other sense connections to reduce their resistance. Further, in some examples, cut portions of traces can be connected to adjacent traces in other sense connections, as illustrated in  FIG. 8 , while in other examples, cut portions of traces can be connected to traces in other sense connections that are not adjacent to the cut portions. 
     In some examples, cut portions of a trace can be reused multiple times to reduce the resistances of sense connections on the touch screen of the disclosure.  FIG. 9  illustrates a sense connection configuration  900  in which cut portions of traces are used by multiple sense connections to reduce the resistances of those sense connections according to examples of the disclosure. In  FIG. 9 , touch node electrodes  902   a - h  are illustrated. In some examples, touch node electrodes  902   b  and  902   c  can be separated from each other by one or more other touch node electrodes (not illustrated), touch node electrodes  902   d  and  902   e  can be separated from each other by one or more other touch node electrodes (not illustrated), touch node electrodes  902   f  and  902   g  can be separated from each other by one or more other touch node electrodes (not illustrated), and touch node electrode  902   h  can be separated from sense circuitry  908  by one or more other touch node electrodes (not illustrated). In order to increase the ability to re-use cut portions of traces multiple times to reduce sense connection resistance, sense connection traces can be ordered in regularly repeating groups, as will be described below. 
     In  FIG. 9 , traces  910   a - j  can be included in Group A, and traces  910   k - t  can be included in Group B. Group A traces can be disposed in a first region of the touch screen, and Group B traces can be disposed in a second region of the touch screen, adjacent the first region. Group A traces can be used to couple touch node electrodes  902   b ,  902   d ,  902   f  and  902   h  to sense circuitry  908 , and Group B traces can be used to couple touch node electrodes  902   a ,  902   c ,  902   e  and  902   g  to sense circuitry  908 . Touch node electrodes  902   b ,  902   d ,  902   f  and  902   h  can be separated from each other by equal numbers of touch node electrodes, as can touch node electrodes  902   a ,  902   c ,  902   e  and  902   g . For example, in a column of 48 touch node electrodes, touch node electrodes  902   b ,  902   d ,  902   f  and  902   h  can correspond to the 47 th , 35 th , 23 rd  and 11 th  touch node electrodes in the column, respectively, and touch node electrodes  902   a ,  902   c ,  902   e  and  902   g  can correspond to the 48 th , 36 th , 24 th  and 12 th  touch node electrodes in the column (e.g., the touch node electrodes corresponding to Group A and Group B traces can be separated from each other by 11 touch node electrodes). The column of touch node electrodes can include additional touch node electrodes, the sense connection traces for which can be configured analogously, and in a pattern similar to, as described here with reference Groups A and B of traces. 
     Focusing on the Group A traces (corresponding to touch node electrodes  902   b ,  902   d ,  902   f  and  902   h ), sense connection  904   h  can include trace  910   j . Portion  950   a  of trace  910   j  can couple sense circuitry  908  to touch node electrode  902   h  at connection point  906   h . Similar to as described with reference to  FIG. 8 , the remainder of trace  910   j  (e.g., the cut portion of trace  910   j  after connection point  906   h ) can be decoupled from portion  950   a  of trace  910   j . Portion  950   b  of trace  910   j  can be electrically connected, in parallel, to traces  910   h - i  in sense connection  904   f  (which can electrically couple touch node electrode  902   f  to sense circuitry  908 ), as illustrated in  FIG. 9 , thus reducing the resistance per unit length of sense connection  904   f  along the length of portion  950   b  of trace  910   j  (and reducing the resistance of sense connection  904   f , overall). Similarly, portions  950   c  of traces  910   h - j  that are not used for electrically connecting touch node electrode  902   f  to sense circuitry  908  can be electrically connected, in parallel, to traces  910   e - g  in sense connection  904   d  (which can electrically couple touch node electrode  902   d  to sense circuitry  908 ), as illustrated in  FIG. 9 , thus reducing the resistance of sense connection  904   d . Finally, portions  950   d  of traces  910   e - j  that are not used for electrically connecting touch node electrode  902   d  to sense circuitry  908  can be electrically connected, in parallel, to traces  910   a - d  in sense connection  904   b  (which can electrically couple touch node electrode  902   b  to sense circuitry  908 ), as illustrated in  FIG. 9 , thus reducing the resistance of sense connection  904   b . In this way, substantially the entirety of traces  910   a - 910   j  can be used on the touch screen to electrically connect touch node electrodes  902   b ,  902   d ,  902   f  and  902   h  to sense circuitry  908 . 
     The Group B traces can be configured analogously to the Group A traces to electrically connect touch node electrodes  902   a ,  902   c ,  902   e  and  902   g  to sense circuitry  908 , as illustrated in  FIG. 9 , the details of which will not be repeated here for brevity. Further, groups of traces corresponding to other touch node electrodes not illustrated in  FIG. 9  (e.g., others of the 48 touch node electrodes in the column of touch node electrodes illustrated) can be analogously configured in the same pattern as is shown with respect to the Group A and B traces, as well. 
     Thus, the examples of the disclosure provide one or more sense connection configurations for tuning the resistive and/or capacitive loads presented to drive and/or sense circuitry in a touch screen. 
     Therefore, according to the above, some examples of the disclosure are directed to a touch sensor panel comprising: a first touch node electrode of a plurality of touch node electrodes, the first touch node electrode coupled to a first sense connection comprising a first set of traces, the first sense connection configured to have a first resistance per unit length that varies along a length of the first sense connection; and a second touch node electrode of the plurality of touch node electrodes, the second touch node electrode coupled to a second sense connection comprising a second set of traces, the second sense connection configured to have a second resistance per unit length that varies along a length of the second sense connection differently than the first resistance per unit length varies along the length of the first sense connection, wherein an effective resistance of the first sense connection and the second sense connection are equal. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first touch node electrode and the second touch node electrode are both in either a row or a column of touch node electrodes on the touch sensor panel. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first sense connection comprises a first number of traces, and the second sense connection comprises a second number of traces, equal to the first number of traces. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first sense connection comprises a first portion and a second portion configured to couple the first touch node electrode to sense circuitry, the first portion of the first sense connection comprising a first number of traces of the first set of traces coupled together, in parallel, and the second portion of the first sense connection comprising a second number of traces, different from the first number of traces, of the first set of traces coupled together, in parallel, and the second sense connection comprises a first portion and a second portion configured to couple the second touch node electrode to the sense circuitry, the first portion of the second sense connection comprising a first number of traces of the second set of traces coupled together, in parallel, and the second portion of the second sense connection comprising a second number of traces, different from the first number of traces, of the second set of traces coupled together, in parallel. Additionally or alternatively to one or more of the examples disclosed above, in some examples, a length of the first portion of the first sense connection and a length of the first portion of the second sense connection are different. Additionally or alternatively to one or more of the examples disclosed above, in some examples, a length of the second portion of the first sense connection and a length of the second portion of the second sense connection are different. Additionally or alternatively to one or more of the examples disclosed above, in some examples, a capacitance of the first sense connection is equal to a capacitance of the second sense connection. Additionally or alternatively to one or more of the examples disclosed above, in some examples, a first respective portion of a first trace of the first set of traces is coupled to the second sense connection. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first trace includes a first portion and a second portion, the second portion of the first trace comprising the first respective portion of the first trace, and the first portion of the first trace decoupled from the second portion of the first trace, the first portion of the first trace is configured to couple the first touch node electrode to sense circuitry, and the second portion of the first trace is configured to couple the second touch node electrode to the sense circuitry. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the second portion of the first trace is coupled, in parallel, to at least a portion of the second set of traces in the second sense connection. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the touch sensor panel further comprises: a third touch node electrode of the plurality of touch node electrodes, the third touch node electrode coupled to a third sense connection comprising a third set of traces, wherein a first respective portion of a second trace of the second set of traces, and a second respective portion of the first trace of the first set of traces are coupled to the third sense connection. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first trace further includes a third portion, the third portion of the first trace comprising the second respective portion of the first trace, and the third portion of the first trace decoupled from the first and second portions of the first trace, the second trace includes a first portion and a second portion, the second portion of the second trace comprising the first respective portion of the second trace, and the first portion of the second trace decoupled from the second portion of the second trace, the first portion of the second trace is configured to couple the second touch node electrode to the sense circuitry, and the second portion of the second trace and the third portion of the first trace are configured to couple the third touch node electrode to the sense circuitry. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the second portion of the second trace and the third portion of the first trace are coupled, in parallel, to at least a portion of the third set of traces in the third sense connection. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the touch sensor panel further comprises: a third touch node electrode and a fourth touch node electrode in a column of touch node electrodes on the touch sensor panel, the column of touch node electrodes including the first touch node electrode and the second touch node electrode, the third touch node electrode coupled to a third sense connection comprising a third set of traces, and the fourth touch node electrode coupled to a fourth sense connection comprising a fourth set of traces, wherein: the first touch node electrode is separated from the second touch node electrode by a first number of touch node electrodes, the third touch node electrode is separated from the fourth touch node electrode by the first number of touch node electrodes, a number of traces in the first set of traces equals a number of traces in the third set of traces, and a number of traces in the second set of traces equals a number of traces in the fourth set of traces. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first touch node electrode is adjacent the third touch node electrode on the touch sensor panel, and the second touch node electrode is adjacent the fourth touch node electrode on the touch sensor panel. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first sense connection and the second sense connection are disposed in a first region of the touch sensor panel, and the third sense connection and the fourth sense connection are disposed in a second region of the touch sensor panel, other than the first region, adjacent the first region. 
     Some examples of the disclosure are directed to a touch sensor panel comprising: a first touch node electrode of a plurality of touch node electrodes, the first touch node electrode coupled to a first sense connection comprising a first portion of a first trace and a second portion of the first trace, the first portion of the first trace configured to couple the first touch node electrode to sense circuitry, and the second portion of the first trace decoupled from the first portion of the first trace; and a second touch node electrode of the plurality of touch node electrodes, the second touch node electrode coupled to a second sense connection comprising a first portion of a second trace and a second portion of the second trace, the first portion of the second trace configured to couple the second touch node electrode to the sense circuitry, and the second portion of the second trace decoupled from the first portion of the second trace, wherein a length of the first portion of the first trace is different from a length of the first portion of the second trace. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first touch node electrode and the second touch node electrode are in a row or a column of touch node electrodes on the touch sensor panel. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the second portion of the first trace and the second portion of the second trace are coupled to a voltage source, different from the sense circuitry. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the voltage source is configured to apply a first voltage to the second portion of the first trace and the second portion of the second trace, and the sense circuitry is configured to apply a second voltage to the first portion of the first trace and the first portion of the second trace. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first voltage is the same as the second voltage. 
     Some examples of the disclosure are directed to a method of fabricating a touch sensor panel, the method comprising: forming a first touch node electrode of a plurality of touch node electrodes, the first touch node electrode coupled to a first sense connection comprising a first set of traces, the first sense connection configured to have a first resistance per unit length that varies along a length of the first sense connection; and forming a second touch node electrode of the plurality of touch node electrodes, the second touch node electrode coupled to a second sense connection comprising a second set of traces, the second sense connection configured to have a second resistance per unit length that varies along a length of the second sense connection differently than the first resistance per unit length varies along the length of the first sense connection, wherein an effective resistance of the first sense connection and the second sense connection are equal. 
     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: 20170421
Publication Date: 20210323
Grant Date: 20210323
Priority Date: 20160729
Inventors: BENNETT, PATRICK
YANG, BYUNG DUK
HUANG, CHUN-YAO
CHIU, HAO-LIN
KNEZ, IVAN
CHANG, PEIEN
KITSOMBOONLOHA, RUNGROT
CHANG, SHIH-CHANG
ONO, SHINYA
LEE, SZUHSIEN
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04166", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04166", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04166", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 61011575