PATENT DOCUMENT

Publication Number: US-9195331-B2
Application Number: US-201113312940-A
Country: US
Kind Code: B2

Title: Common electrode connections in integrated touch screens

Abstract:
Common electrodes (Vcom) of integrated touch screens can be segmented into electrically isolated Vcom portions that can be operated as drive lines and/or sense lines of a touch sensing system. The touch screen can include high-resistivity connections between Vcom portions. The resistivity of the high-resistivity connections can be high enough so that touch sensing and image display can be performed by the touch screen, and the high-resistivity connections can provide an added functionality by allowing a charge build up on one of the Vcom portions to be spread to other Vcom portions and/or discharged from system by allowing charge to leak through the high-resistivity connections. In this way, for example, visual artifacts that result from charge build up on a Vcom portion can be reduced or eliminated.

Claims:
What is claimed is:  
     
       1. An integrated touch screen comprising:
 a plurality of display pixels disposed in an active region of the touch screen; 
 a plurality of common electrodes including first common electrodes and second common electrodes, each display pixel being associated with one of the common electrodes, wherein the first common electrodes are sense common electrodes and the second common electrodes are drive common electrodes; 
 a plurality of first connections between the sense common electrodes or between the drive common electrodes, each first connection conductively connecting two of the sense common electrodes or two of the drive common electrodes; and 
 a plurality of second connections between one of the sense common electrodes and one of the drive common electrodes, each second connection conductively connecting two of the common electrodes comprising one of the sense common electrodes and one of the drive common electrodes and configured to allow a charge to leak through the second connection when the touch screen is powered on, wherein each second connection has a resistivity higher than each first connection. 
 
     
     
       2. The integrated touch screen of  claim 1 , further comprising: a pixel material associated with each display pixel, wherein the pixel material is liquid crystal. 
     
     
       3. The integrated touch screen of  claim 1 , further comprising: a stackup of material layers, the stackup including the plurality of display pixels, wherein one or more of the first or second connections connecting common electrodes includes a first material disposed in the stackup. 
     
     
       4. The integrated touch screen of  claim 3 , wherein the first material is disposed in a same material layer of the stackup as the common electrodes. 
     
     
       5. The integrated touch screen of  claim 3 , wherein the first material is disposed in a different material layer than the common electrodes. 
     
     
       6. The integrated touch screen of  claim 1 , wherein one or more of the second connections connecting common electrodes is an exclusive connection between two of the common electrodes. 
     
     
       7. The integrated touch screen of  claim 1 , further comprising:
 a border region adjacent to the active region, the border region including no display pixels; and 
 a plurality of conductive leads, each conductive lead connected to one of the common electrodes, and at least a portion of each conductive lead being disposed in the border region. 
 
     
     
       8. The integrated touch screen of  claim 7 , wherein one or more of the connections between common electrodes includes one or more second connections between the conductive leads in the border region. 
     
     
       9. The integrated touch screen of  claim 8 , wherein the one or more second connections between two of the conductive leads includes a line. 
     
     
       10. The integrated touch screen of  claim 8 , further comprising:
 a common conductive line, at least a portion of the common conductive line being disposed in the border region, wherein the plurality of conductive leads includes first, second, and third conductive leads conductively connected to third, fourth, and fifth common electrodes included in the plurality of first or second common electrodes, respectively, and each of the first, second, and third conductive leads is conductively connected to the common conductive line through a connection between the conductive line and the conductive lead, such that the connection between the third and fourth common electrodes includes two connections between the conductive line and the first and second conductive leads, and the connection between the fourth and fifth common electrodes includes two connections between the conductive line and the second and third conductive leads. 
 
     
     
       11. The integrated touch screen of  claim 10 , further comprising: a ground conductively connected to the conductive line. 
     
     
       12. The integrated touch screen of  claim 10 , further comprising:
 a plurality of data lines, wherein each display pixel includes a pixel electrode and the pixel electrode is electrically connected to one of the data lines; 
 a display driver that controls voltages of the data lines and the common electrodes to apply a voltage to the pixel material associated with each display pixel, wherein a luminance of each display pixel is controlled based on an amount of the voltage applied to the pixel material, and 
 wherein the display driver controls a voltage of the common electrodes by setting the voltage of the common electrodes to a first voltage value, the integrated touch screen further comprising:
 a display common electrode voltage source that supplies a voltage at the first voltage value, wherein the conductive line is conductively connected to the display common electrode voltage source. 
 
 
     
     
       13. The integrated touch screen of  claim 10 , wherein one or more of the connections between the conductive line and the conductive lead includes a diode. 
     
     
       14. The integrated touch screen of  claim 13 , wherein the anode of each of the one or more diodes is conductively connected to the conductive line, the integrated touch screen further comprising:
 a voltage source electrically connected to the conductive line, wherein a voltage level of the voltage source restricts current from the anode to the cathode of the diode, such that the diode operates as a connection from the conductive line to the conductive lead. 
 
     
     
       15. The integrated touch screen of  claim 14 , wherein the voltage source includes one of a ground and a fixed voltage source. 
     
     
       16. The integrated touch screen of  claim 10 , wherein one or more of the connections between the conductive line and the conductive lead includes a transistor, wherein the source and drain of the transistor are conductively connected to the conductive line and the conductive lead, and the gate of the transistor is electrically connected to a first voltage source that supplies a first voltage to the gate of the transistor, the first voltage maintaining the transistor in the off state, such that the transistor operates as the connection between the conductive line and the conductive lead. 
     
     
       17. The integrated touch screen of  claim 16 , further comprising: a ground conductively connected to the conductive line. 
     
     
       18. The integrated touch screen of  claim 12 , wherein the display driver controls the voltage of the common electrodes by setting the voltage of the common electrodes to a second voltage value, the integrated touch screen further comprising:
 a display common electrode voltage source that supplies a voltage at the second voltage value, wherein the conductive line is conductively connected to the display common electrode voltage source. 
 
     
     
       19. The integrated touch screen of  claim 16 , wherein the source and drain of each of the one or more transistors are conductively connected to the conductive lead and conductive line, respectively, and wherein the transistor is in the on state at a gate voltage of zero volts. 
     
     
       20. The integrated touch screen of  claim 12 , further comprising:
 a touch controller that applies drive signals to one or more of the common electrodes and that receives sense signals resulting from the drive signals, the sense signals indicating an amount of touch on the touch screen, wherein each conductive lead electrically connects one of the common electrodes to at least one of the display driver and the touch controller. 
 
     
     
       21. The integrated touch screen of  claim 1 , wherein the sense signals are generated on one or more of the common electrodes.

Description:
FIELD OF THE DISCLOSURE 
     This relates generally to integrated touch screens that include common electrode portions that can be operated as drive lines and/or sense lines, and in particular, to high-resistivity connections between the common electrode portions. 
     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 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 from a matrix of drive and sense lines of a substantially transparent conductive material, such as Indium Tin Oxide (ITO), often arranged in rows and columns in horizontal and vertical directions on a substantially transparent substrate. It is due in part to their substantial transparency that 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 integrating touch sensing circuitry into a display pixel stackup (i.e., the stacked material layers forming the display pixels). 
     SUMMARY 
     This relates to integrated touch screens in which a common electrode (Vcom) of the display system can be segmented into electrically isolated Vcom portions that can be operated as drive lines and/or sense lines of a touch sensing system. The touch screen can include high-resistivity connections between Vcom portions. The resistivity of the high-resistivity connections can be high enough so that touch sensing and image display can be performed by the touch screen, and the high-resistivity connections can provide an added functionality by allowing a charge build up on one of the Vcom portions to be spread to other Vcom portions and/or discharged from system by allowing charge to leak through the high-resistivity connections. In this way, for example, visual artifacts that result from charge build up on a Vcom portion can be reduced or eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1D  illustrate an example mobile telephone, an example media player, an example personal computer, and an example display that each include an example display screen (which can be part of a touch screen) according to embodiments of the disclosure. 
         FIG. 2  is a block diagram of an example computing system that illustrates one implementation of an example touch screen according to embodiments of the disclosure. 
         FIG. 3  is a more detailed view of the touch screen of  FIG. 2  showing an example configuration of drive lines and sense lines according to embodiments of the disclosure. 
         FIG. 4  illustrates an example configuration in which touch sensing circuitry includes common electrodes (Vcom) according to embodiments of the disclosure. 
         FIG. 5  illustrates an exploded view of display pixel stackups according to embodiments of the disclosure. 
         FIG. 6  illustrates an example touch sensing operation according to embodiments of the disclosure. 
         FIG. 7  illustrates of an example integrated touch screen configuration including high-resistivity connections between Vcom portions according to various embodiments. 
         FIGS. 8-9  illustrate an example integrated touch screen configuration in which various embodiments can be implemented. 
         FIGS. 10-17  illustrate example touch screens according to various embodiments. 
         FIG. 18  illustrates a current versus voltage characteristic curve of an example diode that can be implemented according to various embodiments. 
         FIG. 19  illustrates current versus voltage characteristic curves of two example transistors that can be implemented according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of example embodiments, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific embodiments in which embodiments of the disclosure can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the embodiments of this disclosure. 
     This relates to integrated touch screens in which a common electrode (Vcom) of the display system can be segmented into electrically isolated Vcom portions that can be operated as drive lines and/or sense lines of a touch sensing system. The touch screen can include high-resistivity connections between Vcom portions. The resistivity of the high-resistivity connections can be high enough so that touch sensing and image display can be performed by the touch screen, and the high-resistivity connections can provide an added functionality by allowing a charge build up on one of the Vcom portions to be spread to other Vcom portions and/or discharged from system by allowing charge to leak through the high-resistivity connections. In this way, for example, visual artifacts that result from charge build up on a Vcom portion can be reduced or eliminated. 
       FIGS. 1A-1D  show example systems in which display screens (which can be part of touch screens) according to embodiments of the disclosure may be implemented.  FIG. 1A  illustrates an example mobile telephone  136  that includes a display screen  124 .  FIG. 1B  illustrates an example digital media player  140  that includes a display screen  126 .  FIG. 1C  illustrates an example personal computer  144  that includes a display screen  128 . 
       FIG. 1D  illustrates some details of an example display screen  150 .  FIG. 1D  includes a magnified view of display screen  150  that shows multiple display pixels  153 , each of which can include multiple display sub-pixels, such as red (R), green (G), and blue (B) sub-pixels in an RGB display, for example. The magnified view also shows data lines  155  between each display pixel  153 . 
       FIG. 1D  also includes a magnified view of two of the display pixels  153 , which illustrates that each display pixel can include pixel electrodes  157 , each of which can correspond to one of the sub-pixels, for example. Each pixel electrode can include a plurality of pixel electrode fingers  158 . Each display pixel can include a common electrode (Vcom)  159  that can be used in conjunction with pixel electrodes  157  to operate the display pixel, as will be described below in more detail. In this example embodiment, the Vcom  159  of adjacent display pixels  153  can be separated by an opening, Vcom opening  161 . In this example embodiment, a single data line  155  can be used to operate all three pixel electrodes  157  in a display pixel  153 , for example, by multiplexing the data line, while in other embodiments, the sub-pixels of a display pixel can be operated by separate data lines. In some embodiments, common electrodes can span multiple display pixels of the display screen, such as a single Vcom spanning a rectangular or other shape area of display pixels, and Vcom openings can be formed between these larger areas of Vcom. 
     During a display operation, voltages applied to the common electrodes and to the pixel electrodes can create an electric field through a pixel material (not shown), such as liquid crystal, of each display pixel. In the case of liquid crystal, for example, the electric field can cause inclination of the liquid crystal molecules that can control the amount of light from a backlight (not shown) that passes through a transparent cover (not shown), such as color filter glass. The amount of light passing through the color filter glass can be based on an amount of inclination of the liquid crystal, which can be based on the strength of the electric field through the liquid crystal. In this way, for example, controlling the strength of voltages applied to the liquid crystal of a display pixel can control the luminance of the display pixel. Other pixel materials that can control and/or generate light based on application of voltage to the pixel material could be used, as one skilled in the art would understand. 
     In some embodiments, display screens  124 ,  126 ,  128 , and  150  can be touch screens in which touch sensing circuitry can be integrated into the display pixels. For example, in some embodiments, common electrodes such as Vcom  159  can be conductively connected together to form circuitry used by the touch sensing system. Touch sensing can be based on, for example, self-capacitance or mutual capacitance, or another touch sensing technology. For example, in a self-capacitance based touch system, an individual electrode with a self-capacitance to ground can be used to form a touch pixel for detecting touch. As an object approaches the touch pixel, an additional capacitance to ground can be formed between the object and the touch pixel. The additional capacitance to ground can result in a net increase in the self-capacitance seen by the touch pixel. This increase in self-capacitance can be detected and measured by a touch sensing system to determine the positions of multiple objects when they touch the touch screen. A mutual capacitance based touch system can include, for example, drive regions and sense regions, such as drive lines and sense lines. For example, drive lines can be formed in rows while sense lines can be formed in columns (e.g., orthogonal). Touch pixels can be formed at the “cross-overs” or adjacencies of the rows and columns. It is understood that the drive and sense lines do not actually touch each other at the “cross-overs” or adjacencies, and for example, a dielectric layer, a break in a conductive path, etc., can be disposed between drive and sense lines at the “cross-overs” or adjacencies. During operation, the rows can be stimulated with an AC waveform and a mutual capacitance can be formed between the row and the column of the touch pixel. As an object approaches the touch pixel, some of the charge being coupled between the row and column of the touch pixel can instead be coupled onto the object. This reduction in charge coupling across the touch pixel can result in a net decrease in the mutual capacitance between the row and the column and a reduction in the AC waveform being coupled across the touch pixel. This reduction in the charge-coupled AC waveform can be detected and measured by the touch sensing system to determine the positions of multiple objects when they touch the touch screen. In some embodiments, a touch screen can be multi-touch, single touch, projection scan, full-imaging multi-touch, or any capacitive touch. 
       FIGS. 2-6  show example systems in which display screens with high-resistivity connections between common electrodes according to embodiments of the disclosure may be implemented. 
       100251   FIG. 2  is a block diagram of an example computing system  200  that illustrates one implementation of an example touch screen  220  according to embodiments of the disclosure. Computing system  200  could be included in, for example, mobile telephone  136 , digital media player  140 , personal computer  144 , or any mobile or non-mobile computing device that includes a touch screen. Computing system  200  can include a touch sensing system including one or more touch processors  202 , peripherals  204 , a touch controller  206 , and touch sensing circuitry (described in more detail below). Peripherals  204  can include, but are not limited to, random access memory (RAM) or other types of memory or storage, watchdog timers and the like. Touch controller  206  can include, but is not limited to, one or more sense channels  208 , channel scan logic  210  and driver logic  214 . Channel scan logic  210  can access RAM  212 , autonomously read data from the sense channels and provide control for the sense channels. In addition, channel scan logic  210  can control driver logic  214  to generate stimulation signals  216  at various frequencies and phases that can be selectively applied to drive regions of the touch sensing circuitry of touch screen  220 , as described in more detail below. In some embodiments, touch controller  206 , touch processor  202  and peripherals  204  can be integrated into a single application specific integrated circuit (ASIC). 
     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 . Host processor  228  can use LCD driver  234  to generate an image on touch screen  220 , such as an image of a user interface (UI), and can use touch processor  202  and touch controller  206  to detect a touch on or near touch screen  220 , such a touch input to the displayed UI. The touch input can be used by computer programs stored in program storage  232  to perform actions that can include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device connected to the host device, answering a telephone call, placing a telephone call, terminating a telephone call, changing the volume or audio settings, storing information related to telephone communications such as addresses, frequently dialed numbers, received calls, missed calls, logging onto a computer or a computer network, permitting authorized individuals access to restricted areas of the computer or computer network, loading a user profile associated with a user&#39;s preferred arrangement of the computer desktop, permitting access to web content, launching a particular program, encrypting or decoding a message, and/or the like. Host processor  228  can also perform additional functions that may not be related to touch processing. 
     Touch screen  220  can include touch sensing circuitry that can include a capacitive sensing medium having a plurality of drive lines  222  and a plurality of sense lines  223 . It should be noted that the term “lines” is sometimes used herein to mean simply conductive pathways, as one skilled in the art will readily understand, and is not limited to elements that are strictly linear, but includes pathways that change direction, and includes pathways of different size, shape, materials, etc. Drive lines  222  can be driven by stimulation signals  216  from driver logic  214  through a drive interface  224 , and resulting sense signals  217  generated in sense lines  223  can be transmitted through a sense interface  225  to sense channels  208  (also referred to as an event detection and demodulation circuit) in touch controller  206 . In this way, drive lines and sense lines can be part of the touch sensing circuitry that can interact to form capacitive sensing nodes, which can be thought of as touch picture elements (touch pixels), such as touch pixels  226  and  227 . This way of understanding can be particularly useful when touch screen  220  is viewed as capturing an “image” of touch. In other words, after touch controller  206  has determined whether a touch has been detected at each touch pixel in the touch screen, the pattern of touch pixels in the touch screen at which a touch occurred can be thought of as an “image” of touch (e.g. a pattern of fingers touching the touch screen). 
     In some example embodiments, 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 pixels stackups of a display. An example integrated touch screen in which embodiments of the disclosure can be implemented will now be described with reference to  FIGS. 3-6 .  FIG. 3  is a more detailed view of touch screen  220  showing an example configuration of drive lines and sense lines according to embodiments of the disclosure. As shown in  FIG. 3 , each drive line can be formed of one or more drive line segments that can be electrically connected by drive line links that bypass the sense lines. For example, a first drive line  222  can include a first drive line segment one  301   a , a first drive line segment two  301   b , a first drive line segment three  301   c , etc., that are electrically connected through drive line links  303  at connections  305 . Likewise, a second drive line  302  can include a second drive line segment one  304   a , a second drive line segment two  304   b , a second drive line segment three  304   c , etc., that are electrically connected through drive line links  303  at connections  305 . Drive line links  303  are not electrically connected to the sense lines, such as a first sense line  223  and a second sense line  306 , rather, the drive line links can bypass the sense lines through bypasses  307 . The drive lines and the sense lines can interact capacitively to form touch pixels such as touch pixels  226  and  227 . The drive lines (i.e., the drive line segments and corresponding drive line links) and the sense lines can be formed of electrical circuit elements in touch screen  220 . In the example configuration of  FIG. 3 , each of touch pixels  226  and  227  can include a portion of one drive line segment, a portion of a sense line, and a portion of another drive line segment. For example, touch pixel  226  can include a right-half portion  309  of first drive line segment one  301   a , a top portion  311  of first sense line  223 , and a left-half portion  313  of first drive line segment two  301   b.    
     The circuit elements can include, for example, elements that can exist in conventional LCD displays, as described above. It is noted that circuit elements are not limited to whole circuit components, such 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. 
     Referring to  FIGS. 4-5 , an example integrated touch screen configuration in which common electrodes (Vcom) can form portions of the touch sensing circuitry of a touch sensing system will now be described. Common electrodes are circuit elements of the display system circuitry in the pixel stackup (i.e., the stacked material layers forming the display pixels) of the display pixels of some types of conventional LCD displays, e.g., fringe field switching (FFS) displays; common electrodes can operate as part of the display system to display an image.  FIG. 4  illustrates a plan view of a portion of the example touch screen, and  FIG. 5  is a three-dimensional exploded view showing further details of the display pixel stackup. 
     In the example shown in  FIGS. 4-5 , each sense line can be formed of a single common electrode (also referred to as sense Vcom), and each drive line segment can be formed of a single common electrode (also referred to as drive Vcom). Each single common electrode can span multiple display pixels. For example, first drive line segment one  301   a  can be formed of a single common electrode that is shared by multiple display pixels, such as a display pixel  401  and a display pixel  403 . For the sake of clarity, only two display pixels are illustrated, although it is to be understood that touch screen  220  can include many display pixels. Each single common electrode can be separated from other common electrodes by Vcom conductive breaks  405 , which can be physical gaps between common electrodes. Thus, the drive Vcom of the drive lines can be conductively isolated from the sense Vcom of the sense lines. In other words, an electrical open can exist between the drive lines and the sense lines. Likewise, the drive Vcom of each drive line can be conductively isolated from the drive Vcom of the other drive lines. 
     Electrical charge that can build up on one of the conductively isolated portions of Vcom may create a charge imbalance among the portions of Vcom, which can result visual artifacts such as increases or decreases in brightness of the display pixels associated with the Vcom having the charge build up. Charge build up (i.e., positive charge or negative charge) can be caused by, for example, electrostatic discharge (ESD) that can occur during handling of device components by a person or machine in the manufacturing process, during shipping, during handling of the device by a user, during repair of the device, etc. 
     For example, a bonding machine used during manufacture may accidentally create an ESD when touching a conductive line connected to first drive line segment one  301   a.  As described above, the drive line segments of first drive line  222  can be conductively isolated from the other drive lines and the sense lines. The electrical opens existing between the drive lines and between the drive lines and sense lines can prevent the charge from the ESD from spreading from first drive line segment one  301   a  to the sense lines or spreading to other drive lines. However, the charge applied to first drive line segment one  301   a  can be distributed among all of the drive line segments of first drive line  222  through the drive line links that conductively connect together the drive line segments, as described above with reference to  FIG. 3 . In this regard, some of the display pixels in the drive line segments, such as display pixel  401 , can include tunnel connections  407  that connect the drive Vcom of the display pixel&#39;s drive line segment to a conductive pathway that bypasses a sense line and connects to another drive line segment. The build up of charge on first drive line  222  due to the spreading of the ESD charge through drive line links can result in a visual artifact associated with the first drive line, such as the display pixels in the drive line segments of the first drive line appearing abnormally brighter than the other display pixels of touch screen  220 . Various example embodiments that can reduce or eliminate such visual artifacts by distributing charge among all of the portions of Vcom in a touch screen and/or by reducing or removing charge build up using high-resistivity connections to Vcom portions will be described in more detail below with reference to FIGS.  7  and  10 - 19 . 
       FIG. 5  shows further details of an example drive line link that includes a tunnel line that bypasses sense Vcom in an example touch screen according to various embodiments.  FIG. 5  is a three-dimensional illustration of an exploded view (expanded in the z-direction) of example display pixel stackups  500  showing some of the elements within the pixel stackups of example integrated touch screen  220 . Stackups  500  can include elements in a first metal (M 1 ) layer  501 , a second metal (M 2 ) layer  503 , and a common electrode (Vcom) layer  505 . M 1  layer  501  can include gate lines  518 . M 1  layer  501  can also include tunnel lines (also referred to as bypass lines)  519  that can electrically connect together drive line segments of a drive line through conductive vias  521  that connect the tunnel line to tunnel connections  407  in display pixels of two or more drive line segments. Tunnel line  519  can run through the display pixels of sense line  517  with no connections to the Vcom in the sense line, e.g., no vias  521  in display pixels of the sense line. One or more tunnel lines  519  can be used to connect drive line segments together. M 2  layer  503  can include data lines  523 , for example. Only one data line  523  is shown for the sake of clarity; however, a touch screen can include multiple data lines running through each vertical row of pixels. 
     Structures such as tunnel lines  519  and conductive vias  521  can operate as a touch sensing circuitry of a touch sensing system to detect touch during a touch sensing phase of the touch screen. Structures such as data lines  523 , along with other pixel stackup elements such as transistors, pixel electrodes, common voltage lines, etc. (not shown), can operate as display circuitry of a display system to display an image on the touch screen during a display phase. Structures such as the drive Vcom of the drive line segments and the sense Vcom of the sense lines can operate as multifunction circuit elements that can operate as part of both the touch sensing system and the display system. 
     For example, in operation during a touch sensing phase, stimulation signals (also referred to as drive signals) can be transmitted through a drive line, e.g., the drive line segments connected by tunnel lines  519  and conductive vias  521 , to form electric fields between the stimulated drive line segments and the sense lines to create touch pixels, such as touch pixel  226  in  FIG. 2 . In this way, the connected together drive line segments can operate as a drive line, such as drive line  222 . When an object such as a finger approaches or touches a touch pixel, the object can affect the electric fields extending between the drive line segments and the sense line, thereby reducing the amount of charge capacitively coupled to the sense region. This reduction in charge can be sensed by a sense channel of a touch sensing controller connected to the touch screen, such as touch controller  206  shown in  FIG. 2 , and stored in a memory along with similar information of other touch pixels to create an “image” of touch. 
     A touch sensing operation according to embodiments of the disclosure will be described with reference to  FIG. 6 .  FIG. 6  shows partial circuit diagrams of some of the touch sensing circuitry associated with first drive line  222 , including first drive line segment one  301   a  and first drive line segment two  301   b , and first sense line  223  according to embodiments of the disclosure.  FIG. 6  also shows further details of circuit elements of display pixel  401 . For the sake of clarity,  FIG. 6  includes circuit elements illustrated with dashed lines to signify some circuit elements operate primarily as part of the display circuitry and not the touch sensing circuitry. Display pixel  401  can include a TFT  609 , a gate line  612 , a data line  614 , a pixel electrode  616 , and a common electrode  618 . 
     During a touch sensing phase, a drive signal  619 , such as an alternating current (AC) drive signal, can be applied to the drive line segments of drive line  222  through tunnel lines  519  and conductive vias  521  that connect the drive line segments together. Drive signal  619  can generate electrical fields  623  between the drive line segments and the sense lines. For example, electrical fields  623  can be generated between first drive line segment one  301   a  and first sense line  223 , and between first drive line segment two  301   b  and the first sense line. The first sense line can be connected to a sense amplifier, such as a charge amplifier  626 . Thus, drive signal  619  can inject electrical charge into first sense line  223 , and charge amplifier  626  can convert the injected charge into a voltage that can be measured. The amount of charge injected, and consequently the measured voltage, can depend on the proximity of a touch object, such as a finger  627 , to the corresponding region of the touch screen, i.e., touch pixel  226 . In this way, the measured voltage can provide an indication of touch on or near the touch screen. 
       FIG. 7  illustrates of an example integrated touch screen configuration including high-resistivity connections between Vcom portions according to various embodiments. A touch screen  700  can include drive lines including drive Vcom segments and sense lines including sense Vcom, similar to the configuration of example touch screen  220  illustrated in  FIG. 4 . Touch screen  700  can include a first drive line  701  that includes drive Vcom portions including a first drive line segment one  703   a , a first drive line segment two  703   b , and a first drive line segment three  703   c . A second drive line  705  can include a second drive line segment one  707   a,  a second drive line segment two  707   b , and a second drive line segment three  707   c . The drive line segments in each drive line can be conductively connected together through tunnel connections  709  that connect the drive Vcom in each drive line segment to a tunnel line (not shown) such as tunnel line  519 . Touch screen  700  can include a first sense line  711  and a second sense line  713  that each includes a sense Vcom portion. Vcom openings can create Vcom conductive breaks  715  between the drive lines and the sense lines, and between the drive lines. 
     Touch screen  700  can include high-resistivity connections that can conductively connect Vcom portions across a Vcom conductive break  715 . As used herein, a high-resistivity connection is a connection between two or more Vcom portions, where the connection has an electrical resistance that is high enough to allow the Vcom portions to operate as separate circuit elements of the touch sensing system, e.g., a drive line or a sense line, and where the electrical resistance is low enough to allow electrical charge to leak through the connection as a direct electrical current. In the example touch sensing operation described above with reference to  FIG. 6 , a high-resistivity connection between a drive Vcom portion of a drive line and a sense Vcom portion of a sense line would have an electrical resistance high enough to allow drive signal  619  to generate electric field  623  between the drive line and the sense line such that a touch object can be sensed as described above. 
     Referring to  FIG. 7 , some connections, such as high-resistivity connections  717 , can conductively connect together two drive lines. In the example configuration of  FIG. 7 , a single high-resistivity connection  717  between first drive line segment one  703   a  and second drive line segment one  707   a  can conductively connect all of the drive line segments of first drive line  701  and all of the drive line segments of second drive line  705 . Other connections, such as high-resistivity connections  719 , can conductively connect together a drive line and a sense line. In the example configuration of  FIG. 7 , a single high-resistivity connection between first drive line segment one  703   a  and first sense line  711  can conductively connect all of the drive line segments of the first drive line to the first sense line. Likewise, a single high-resistivity connection  719  between first drive line segment two  703   b  and second sense line  713  can conductively connect all of the drive line segments of the first drive line to the second sense line. Therefore, some of the charge in a charge build up on any portion of Vcom in touch screen  700  can leak through one or more high-resistivity connections to spread the charge throughout all of the portions of Vcom. 
     Distributing a charge build up across all Vcom portions can reduce the appearance of visual artifacts in two ways. First, the amount of charge that builds up on a single Vcom portion, due to an ESD on that Vcom portion, for example, can be reduced because the charge can leak out to other Vcom portions. Thus, the amount of localized charge can be reduced, which can reduce the severity of a local visual artifact associated with the Vcom portion initially receiving the ESD. Second, the charge can be distributed evenly among all Vcom portions, which can result a uniform display error, such as a uniform increase or decrease in brightness of all display pixels. A uniform increase or decrease in brightness can be much harder to detect as a visual artifact than a localized increase or decrease in brightness. In sum, distributing a charge build up can result in a smaller, more uniform display error, which can result in a reduced or undetectable visual artifact. 
     In example touch screen  700 , each high-resistivity connection can be an exclusive high-resistivity connection between two conductively isolated Vcom portions. As used herein, an exclusive high-resistivity connection between two conductively isolated Vcom portions is a high-resistivity connection through which charge can flow only from one Vcom portion to the other Vcom portion, or vice versa. It is to be noted that once the charge has flowed from one Vcom portion to the other Vcom portion through the exclusive high-resistivity connection, it is possible that the charge may be leaked from the other Vcom portion into one or more additional conductively isolated Vcom portions through one or more additional high-resistivity connections that may exist. For example, electrical charge flowing from first sense line  711  through high-resistivity connection  719  between the first sense line and drive line segment one  703   a  can only flow into the first drive line segment one, and vice versa. Accordingly, high-resistivity connection  719  between first sense line  711  and first drive line segment one  703   a  is an exclusive high-resistivity connection. 
     In example touch screen  700 , the high-resistivity connections can be, for example, conductive pathways that include a high-resistivity material. In some embodiments, the high-resistivity material can be formed in the same layer of the pixel stackup as the Vcom portions. In some embodiments, the high-resistivity material can be formed in a different layer as the Vcom portions, and can be connected to the Vcom portions through vias, for example. 
     One skilled in the art would readily understand that more or fewer high-resistivity connections and/or different configurations of high-resistivity connections can be used. For example, some embodiments can include only high-resistivity connections between the drive lines and the sense lines, such as high-resistivity connections  719 , and may not include high-resistivity connections between drive line segments, such as high-resistivity connections  717 . In these embodiments, charge on one of the drive lines can be leaked to each sense line through one high-resistivity connection, and leaked to another drive line through two high-resistivity connections in series. Compared to the example configuration illustrated in  FIG. 7 , some embodiments can include additional high-resistivity connections. For example, some embodiments can include a high-resistivity connection at every Vcom conductive break between two Vcom portions. In this way, for example, multiple parallel conductive pathways can be provided, which can allow a localized charge build up to be more quickly distributed among the Vcom portions. 
       FIGS. 8-9  illustrate an example integrated touch screen configuration in which various embodiments can be implemented. An integrated touch screen  800  can include a display pixel stackup with a common electrode layer including Vcom conductive breaks  801  between multiple Vcom portions, which can be configured into drive lines and sense lines, for example, as in example touch screen  220  described above. Each of a first drive line  803 , a second drive line  805 , a third drive line  807 , a fourth drive line  809 , and a fifth drive line  811  can include multiple drive line segments  813  conductively connected together with drive line links (not shown). A first sense line  815 , a second sense line  817 , and a third sense line  819  can each include a single Vcom portion. Each drive line can electrically connected to a driver integrated circuit (IC)  821  through a drive line lead  823 , and each sense line can be electrically connected to the driver IC through a sense line lead  825 . Drive line leads  823  and sense line leads  825  can be conductive wires that can carry drive signals from driver IC  821  to the drive lines and carry sense signals from the sense lines to the driver IC, respectively. Driver IC  821  can control the touch sensing operation of the drive lines and sense lines, for example, as in the example touch sensing operation described above in reference to  FIG. 6 . In some embodiments, driver IC  821  can also control the display operation of touch screen  800  to display images on the touch screen. 
       FIG. 9  shows portions of driver IC  821 , drive line leads  823 , and sense line leads  825  in greater detail. In this example embodiment, drive line leads  823  and sense line leads  825  can run through a border region  901  of touch screen  800 . Border region  901  can be a region bordering the active display and touch sensing area of touch screen  800  and can include circuit elements, such as conductive lines, switches, busses, etc., that can connect the display and touch sensing circuitry in the active area to one or more devices that can control the circuitry to display images and/or sense touches on the touch screen, such as driver IC  821 . In some embodiments, circuit elements in border region  901  can be formed on the same substrate as the circuit elements in the active area. For example, the stackup of display pixels can be formed on silicon dioxide substrate using semiconductor manufacturing processes such as masking, depositing material layers, etching, doping, etc. In some embodiments, the silicon dioxide substrate can extend beyond the active area to create a border region, and circuit elements can be formed in the border region using the same semiconductor manufacturing processes. 
       FIG. 10  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1000  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1001  and sense line leads  1003  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1005  of touch screen  1000 . A driver IC  1007  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1000 . 
     Touch screen  1000  can include high-resistivity connections, such as high-resistivity material lines  1009 , which can be conductive pathways that include a high-resistivity material. Each high-resistivity material line  1009  can connect together two drive line leads  1001 , two sense line leads  1003 , or a drive line lead and a sense line lead. Consequently, a charge build up on the Vcom of one of the drive or sense lines can be spread to each of the other drive and sense lines by leaking through one or more high-resistivity material lines  1009 . For example, charge from a charge build up on the fifth drive line can leak through a single high-resistivity material line  1009  into the fourth drive line, can leak through two high-resistivity material lines  1009  into the third drive line, etc . . . , and can leak through seven high-resistivity material lines  1009  into the third sense line. 
       FIG. 11  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1100  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1101  and sense line leads  1103  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1105  of touch screen  1100 . A driver IC  1107  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1100 . 
     Touch screen  1100  can include high-resistivity connections, such as high-resistivity material lines  1109 , which can be conductive pathways that include a high-resistivity material. Each high-resistivity material line  1109  can connect a single drive line lead  1101  to a common conductive line  1111 , or can connect a single sense line lead  1103  to the common conductive line. In other words, common conductive line can be a common node that connects to each of multiple electrically isolated Vcom portions (e.g., drive lines and sense lines) through a high-resistivity connection (e.g., a high-resistivity material line  1109 ). Consequently, a charge build up on the Vcom of one of the drive or sense lines can be spread to each of the other drive and sense lines by leaking through two high-resistivity material lines  1009 . For example, charge from a charge build up on the fifth drive line can leak into the fourth drive line by leaking through high-resistivity material line  1109  connecting the fifth drive line lead to common conductive line  1111  and then leaking through high-resistivity material line  1109  connecting the fourth drive line lead to the common conductive line. Likewise, charge on any of the drive lines or sense lines can leak into any other drive line or sense line by leaking through two high-resistivity material lines  1109  connected by common conductive line  1111 . 
     In this example configuration of  FIG. 11 , common conductive line  1111  can be electrically isolated from other circuit elements of touch screen  1100 .  FIGS. 12-13  illustrate example configurations in which a common conductive line can be additionally connected to various other circuit elements. 
       FIG. 12  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1200  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1201  and sense line leads  1203  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1205  of touch screen  1200 . A driver IC  1207  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1200 . 
     Touch screen  1200  can include high-resistivity connections, such as high-resistivity material lines  1209 , which can be conductive pathways that include a high-resistivity material. Each high-resistivity material line  1209  can connect a single drive line lead  1201  to a common conductive line  1211 , or can connect a single sense line lead  1203  to the common conductive line. Common conductive line  1211  can be connected to an electrical ground  1213 , such as a chassis ground, an earth ground, etc. Consequently, a charge build up on the Vcom of any of the drive lines or sense lines can be leaked through a single high-resistivity material line  1209  and flow through common conductive line  1211  into ground  1213 . In this way, for example, a charge build up on one, multiple, or all of the drive lines and/or sense lines can be reduced or eliminated. 
       FIG. 13  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1300  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1301  and sense line leads  1303  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1305  of touch screen  1300 . A driver IC  1307  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1300 . 
     Touch screen  1300  can include high-resistivity connections, such as high-resistivity material lines  1309 , which can be conductive pathways that include a high-resistivity material. Each high-resistivity material line  1309  can connect a single drive line lead  1301  to a common conductive line  1311 , or can connect a single sense line lead  1303  to the common conductive line. Common conductive line  1311  can be connected to a display Vcom voltage  1313 . A voltage level of display Vcom voltage  1313  can be the voltage level applied to the Vcom during the display phase to display an image on touch screen  1300 . Consequently, a charge build up on the Vcom of one of the drive or sense lines of touch screen  1300  can be spread to each of the other drive and sense lines by leaking through two high-resistivity material lines  1309 , while display Vcom voltage  1313  can help maintain the desired voltage level on the Vcom portions of touch screen  1300 . 
       100571   FIG. 14  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1400  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1401  and sense line leads  1403  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1405  of touch screen  1400 . A driver IC  1407  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1400 . 
     Touch screen  1400  can include diodes  1409 . Each diode  1409  can connect a single drive line lead  1401  to a common conductive line  1411 , or can connect a single sense line lead  1403  to the common conductive line. Each diode  1409  can be configured such that the cathode is connected to the drive line or sense line and the anode is connected to common conductive line  1411 , which can allow only a small diode leakage current to pass from the cathode to the anode of the diode. Thus, each diode  1409  can provide a high-resistivity connection from the drive line or sense line to common conductive line  1411 . In addition, common conductive line  1411  can be connected to an electrical ground  1413 , such as a chassis ground, an earth ground, etc. In this regard, diodes  1409  can be configured to provide a high-resistivity connection from common conductive line  1411  to the drive lines and sense lines when the common conductive line (and hence the anode of each diode) is connected to ground. 
       FIG. 18  illustrates an example current vs. voltage characteristic curve  1800  of diode  1409  according to various embodiments. At zero volts (e.g., ground) a forward current through diode  1409  can be very low, such that the diode can provide a high-resistivity connection from common conductive line  1411  to the drive lines and sense lines. It should be understood that charge leaking from the drive lines and the sense lines through diodes  1409  into common conductive line  1411  can flow to ground  1413  without causing a significant change in voltage at the anodes of the diodes. Consequently, charge flowing out of the drive and/or sense lines can flow to ground  1413 . In this way, for example, a charge build up on one, multiple, or all of the drive lines and/or sense lines can be reduced or eliminated. 
       FIG. 15  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1500  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1501  and sense line leads  1503  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1505  of touch screen  1500 . A driver IC  1507  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1500 . 
     Touch screen  1500  can include diodes  1509 . Each diode  1509  can connect a single drive line lead  1501  to a common conductive line  1511 , or can connect a single sense line lead  1503  to the common conductive line. Each diode  1509  can be configured such that the cathode is connected to the drive line or sense line and the anode is connected to common conductive line  1511 . Thus, similar to the example configuration of  FIG. 14 , each diode  1509  of touch screen  1500  can provide a high-resistivity connection from the drive line or sense line to common conductive line  1511 . In addition, common conductive line  1511  can be connected to a voltage source, such as a low gate line voltage source (VGL)  1513 . VGL  1513  can be, for example, a shared voltage source that can supply voltage to multiple circuit elements of touch screen  1500 . In this example, the voltage level of VGL  1513  can be fixed at −5V. Diodes  1509  can be configured to provide a high-resistivity connection from common conductive line  1511  to the drive lines and sense lines when the common conductive line (and hence the anode of each diode) is connected to a voltage of −5V. For example, diodes  1509  can have the current versus voltage characteristic curve illustrated in  FIG. 18 . Referring to  FIG. 18 , at a voltage level of −5V, a forward current through diode  1509  can be very low, such that the diode can provide a high-resistivity connection from common conductive line  1511  to the drive lines and sense lines. It should be understood that charge from a charge build up in one drive line or sense line can leak from the drive or sense line through the corresponding diode  1509  into common conductive line  1511 , and can subsequently leak through one or more other diodes  1509  into other drive lines and sense lines. In this way, for example, a charge build up on one or more drive lines and/or sense lines can be distributed throughout all of the drive lines and sense lines. 
       FIG. 16  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1600  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1601  and sense line leads  1603  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1605  of touch screen  1600 . A driver IC  1607  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1600 . 
     Touch screen  1600  can include transistors  1609 . The source of each transistor  1609  can be connected to a single drive line lead  1601  or to a single sense line lead  1603 , and the drain of each of the transistors can be connected to a common conductive line  1611 . The gates of each transistor  1609  can be connected to a voltage source, such as a low gate voltage source (VGL)  1613 , which can be at a fixed voltage, such as −5V. Each transistor  1609  can be configured such that the voltage level of VGL  1613  applied to the gate of the transistor can maintain the transistor in the “off” state, which can allow only small transistor leakage current to pass from the source to the drain, or vice versa. Thus, each transistor  1609  of touch screen  1600  can provide a high-resistivity connection between a drive line and common conductive line  1611 , or between a sense line and the common conductive line. 
     Common conductive line  1611  can be connected to an electrical ground  1613 , such as a chassis ground, an earth ground, etc. Charge leaking from the drive lines and the sense lines through transistors  1609  into common conductive line  1611  can flow to ground  1613 . In this way, for example, a charge build up on one, multiple, or all of the drive lines and/or sense lines can be reduced or eliminated. 
       FIG. 17  illustrates a portion of a border region of an example touch screen according to various embodiments. A touch screen  1700  can include an active area with drive lines and sense lines (not shown) configured as described in example touch screen  800 . Drive line leads  1701  and sense line leads  1703  can be configured as drive line leads  823  and sense line leads  825 , respectively, and can run through a border region  1705  of touch screen  1700 . A driver IC  1707  can be configured as driver IC  821  and can control the touch sensing operation of touch screen  1700 . 
     Touch screen  1700  can include transistors  1709 . The source of each transistor  1709  can be connected to a single drive line lead  1701  or to a single sense line lead  1703 , and the drain of each of the transistors can be connected to a common conductive line  1711 . The gates of each transistor  1709  can be connected to a voltage source, such as a low gate voltage source (VGL)  1713 , which can be at a fixed voltage, such as −5V. Each transistor  1709  can be configured such that the voltage level of VGL  1713  applied to the gate of the transistor can maintain the transistor in the “off” state, which can allow only small transistor leakage current to pass from the source to the drain, or vice versa. Thus, each transistor  1709  of touch screen  1700  can provide a high-resistivity connection between a drive line and common conductive line  1711 , or between a sense line and the common conductive line. 
     Common conductive line  1711  can be connected to a display Vcom voltage  1715 . A voltage level of display Vcom voltage  1715  can be the voltage level applied to the Vcom during the display phase to display an image on touch screen  1700 . Consequently, a charge build up on the Vcom of one of the drive or sense lines of touch screen  1700  can be spread to each of the other drive and sense lines by leaking through two transistors  1709 , while display Vcom voltage  1715  can help maintain the desired voltage level on the Vcom portions of touch screen  1700 . 
       FIG. 19  illustrates current versus voltage characteristic curves of example transistors that can be implemented in high-resistivity connections according to various embodiments. For example, a transistor having a characteristic curve  1900  can be implemented as transistor  1609  or transistor  1709  in the example embodiments above. During operation of the example touch screens in these example embodiments, the gate of the transistor can be held at a voltage of −5 V, for example. As shown in characteristic curve  1900 , a −5 V gate voltage can maintain the transistor in the off state, allowing the transistor to provide a high-resistivity for a high-resistivity connection. When the gate voltage of the transistor is maintained at zero volts, for example, the transistor also be in the off state as shown in characteristic curve  1900 . 
     The gate voltage of the transistor can be zero volts in a variety of different situations. For example, the touch screen can be powered off occasionally during normal operational use. In another example, the gate voltage can be zero volts during the manufacture of the touch screen, e.g., when the gate voltage is electrically floating before the gate is connected to an active voltage source. Because a transistor having a characteristic curve  1900  would be in the off state during a power off situation, when the gate voltage is electrically floating, for example, any charge of a charge build up in one common electrode of the example touch screens would be required to leak through high-resistivity connection in order to spread to other common electrodes. 
     However, as will now be described in more detail, using a transistor having a characteristic curve  1901 , for example, can allow charge spreading among common electrodes to occur more quickly during power off situations, when the gate voltage is electrically floating, etc. For example, a transistor having a characteristic curve  1901  can be implemented as transistor  1609  or transistor  1709  in the example embodiments above. During operation of the example touch screens in these example embodiments, the gate of the transistor can be held at a voltage of −5 V. As shown in characteristic curve  1901 , a −5 V gate voltage can maintain the transistor in the off state, allowing the transistor to provide a high-resistivity for a high-resistivity connection. However, when the gate voltage of the transistor is zero volts, for example, the transistor can be in the on state as shown in characteristic curve  1901 . Therefore, implementing a transistor having a characteristic curve that allows the transistor to be in the off state during operation of the touch screen and to be in the on state when the gate voltage of the transistor is zero volts can provide faster discharge and/or spreading of charge due to, for example, ESD. 
     Although embodiments of this disclosure have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications including, but not limited to, combining features of different embodiments, omitting a feature or features, etc., as will be apparent to those skilled in the art in light of the present description and figures. 
     For example, although the foregoing example embodiments describe integrated touch screens in which Vcom portions can include drive lines and sense lines, one skilled in the art would readily understand that in some embodiments the Vcom portions can include only the drive lines, and that the sense lines can be disposed elsewhere, such as in a different material layer of the stackup. In this case, in some embodiments the sense lines can be dual-function elements that operate as part of the touch sensing circuitry and as part of the display circuitry, or while other embodiments, the sense lines can be single-function elements that operate as part of the touch sensing circuitry only. Likewise, in some embodiments, the Vcom portions can include only the sense lines, and the drive lines can be disposed elsewhere. 
     Furthermore, while the high-resistivity connections of example touch screen  700  are described as lines including high-resistivity material, it is to be understood that in some embodiments these high-resistivity connections can be diodes, transistors, etc., for example, as described in the example embodiments of  FIGS. 14-19 . It is also to be understood that various types of high-resistivity connections can be utilized in various embodiments as exclusive connections and/or non-exclusive connections, and can be formed within the active area of a touch screen, within the border region of a touch screen, and/or at a different location. 
     Also, while each drive line segment and sense line can be formed of a single Vcom that spans multiple display pixels in the various example embodiments, in some embodiments, each drive line segment and sense line can be formed of multiple, separate common electrodes that can be conductively connected together to form drive region segments and sense regions that generally correspond to drive line segments and sense lines. For example, in some embodiments each display pixel can include an individual Vcom, and a Vcom opening can exist between the Vcom each display pixel and the Vcoms of adjacent display pixels, such that the Vcoms are conductively isolated from each other in the Vcom layer of the pixel stackup. Multiple Vcoms can be conductively connected, for example, by conductive lines in an additional metal layer of the pixel stackup, such that the individual display pixel Vcoms can be electrically grouped to form drive line segments and sense lines. In these embodiments, high-resistivity connections can include high-resistivity connections between individual Vcoms in different drive lines and/or between a drive line and a sense line. In some embodiments, high-resistivity connections could include high-resistivity connections between the conductive lines connected to the individual Vcoms of the drive regions of different drive lines or between the drive region of a drive line and the sense region of a sense line. 
     While the each of the drive lines and sense lines in the various example embodiments are shown as generally rectangular regions of multiple Vcom portions or a single Vcom portion, respectively, the drive lines and sense lines are not limited to the shapes, orientations, and positions shown, but can include any suitable configurations as one skilled in the art would understand. For example, in some embodiments each drive line can be formed of a single Vcom portion, and each sense line can be formed of multiple sense line segments of Vcom that can be connected together with sense line links that bypass the drive lines. Furthermore, it is to be understood that the display pixels used to form the touch pixels are not limited to those described above, but can be any suitable size or shape to permit touch capabilities according to embodiments of the disclosure. 
     Although specific materials and types of materials may be included in the descriptions of example embodiments, one skilled in the art will understand that other materials that achieve the same function can be used. In some embodiments, the drive lines and/or sense lines can be formed of other elements including, for example other elements already existing in typical LCD displays (e.g., other electrodes, conductive and/or semiconductive layers, metal lines that would also function as circuit elements in a typical LCD display, for example, carry signals, store voltages, etc.), other elements formed in an LCD stackup that are not typical LCD stackup elements (e.g., other metal lines, plates, whose function would be substantially for the touch sensing system of the touch screen), and elements formed outside of the LCD stackup (e.g., such as external substantially transparent conductive plates, wires, and other elements). For example, part of the touch sensing system can include elements similar to known touch panel overlays. 
     In the foregoing example embodiments, each sub-pixels can be a red (R), green (G) or blue (B) sub-pixel, with the combination of all three R, G and B sub-pixels forming one color display pixel. Although this example embodiment includes red, green, and blue sub-pixels, a sub-pixel may be based on other colors of light or other wavelengths of electromagnetic radiation (e.g., infrared) or may be based on a monochromatic configuration.

Metadata:
Filing Date: 20111206
Publication Date: 20151124
Grant Date: 20151124
Priority Date: 20111206
Inventors: YU CHENG-HO
GE ZHIBING
XU MING
CHANG SHIH CHANG
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L2224/48137", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/13091", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48137", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2924/13091", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04164", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L2224/48137", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/13091", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13338", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/48137", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 46981119