PATENT DOCUMENT

Publication Number: US-8593450-B2
Application Number: US-97697810-A
Country: US
Kind Code: B2

Title: Relay driving of conductive segments in displays

Abstract:
Multiple Vcom segments of display screens can be driven in a relay fashion, such that the driving of different Vcom segments overlaps. For example, a Vcom signal can be applied to a first segment of Vcom, and lines of display pixels in the first segment can be scanned. When scanning nears the end of the first segment, a Vcom signal can be applied to the next segment of Vcom before scanning in the first segment ends. For example, when the second-to-the-last line of display pixels in a segment of Vcom is scanned, the next Vcom segment can be driven with a Vcom signal. Likewise, when scanning in the next segment of Vcom begins, the Vcom signal can continue to be applied to the first segment of Vcom until a few lines of display pixels in the next segment have been scanned.

Claims:
What is claimed is: 
     
       1. A method of displaying an image on a display including a plurality of lines of display pixels, each display pixel being associated with a common electrode, the method comprising:
 applying a first signal to the common electrode associated with each of a plurality of display pixels in a first group of display pixels, the first group including one or more of the plurality of lines of display pixels, wherein the first signal is an alternating current signal; 
 scanning a first set of the lines of display pixels of the first group while not applying a second signal to the common electrode associated with each of a plurality of display pixels in a second group of display pixels, the second group including one or more of the plurality of lines of display pixels different from the first group, wherein the second signal is an alternating current signal; 
 applying the second signal to the common electrode associated with each of the plurality of display pixels in the second group; 
 scanning a second set of the lines of display pixels of the first group while the first and second signals are being applied 
 discontinuing application of the first signal; and 
 scanning a third set of the lines of display pixels of the second group while the second signal is being applied. 
 
     
     
       2. The method of  claim 1 , wherein scanning the third set of the lines includes scanning the third set of the lines prior to discontinuing application of the first signal, such that the third set of lines is scanned while the first and second signals are being applied. 
     
     
       3. The method of  claim 2 , the method further comprising:
 scanning a fourth set of the lines of display pixels of the second group while the second signal is being applied and after discontinuation of the first signal. 
 
     
     
       4. The method of  claim 1 , wherein the common electrode associated with each of the plurality of display pixels in the first group includes a first common electrode that is a contiguous layer of conductive material associated with a plurality of the display pixels. 
     
     
       5. The method of  claim 1 , wherein the common electrode associated with each of the plurality of display pixels in the first group includes an individual common electrode associated with each of the display pixels, wherein a plurality of the individual common electrodes are electrically connected together. 
     
     
       6. The method of  claim 5 , wherein all of the individual common electrodes associated with the display pixels in the first group are electrically connected together through a plurality of conductive lines within a plurality of stackups of the display pixels. 
     
     
       7. The method of  claim 5 , wherein a first subset of the individual common electrodes are electrically connected together, a second subset of the individual common electrodes are electrically connected together, and the first and second subsets are electrically disconnected within a plurality of stackups of the display pixels. 
     
     
       8. The method of  claim 1 , wherein the common electrode associated with the display pixels in the second group is electrically floating after discontinuing application of at least one of the first or second signal to the common electrode. 
     
     
       9. The method of  claim 1 , wherein the common electrode associated with the display pixels in the second group is electrically connected to a fixed voltage after discontinuing application of at least one of the first or second signal to the common electrode. 
     
     
       10. The method of  claim 1 , wherein applying the first and second signals occur during a display operation, the method further comprising:
 operating, during a touch sensing operation, the common electrodes associated with each of the display pixels in the first group as one of a drive line and a sense line, wherein operating the common electrodes as the drive line includes applying stimulation signals to the common electrodes, and operating the common electrodes as the sense line includes receiving sense signals from the common electrodes. 
 
     
     
       11. The method of  claim 10 , further comprising:
 applying a third signal to the common electrode associated with each of a plurality of display pixels in a third group, wherein the third signal is an alternating current signal, the third signal being applied during the scanning of the first, second, and third sets of lines. 
 
     
     
       12. The method of  claim 11 , wherein the third group includes the display pixels in the first, second, and third sets of lines. 
     
     
       13. The method of  claim 11 , further comprising:
 operating, during the touch sensing operation, the common electrodes associated with each of the display pixels in the third group as the drive line, if the common electrodes associated with the first group are being operated as the sense line, and operating the common electrodes associated with the third group as the sense line, if the common electrodes associated with the first group are being operated as the drive line. 
 
     
     
       14. A non-transitory computer-readable storage medium storing computer-executable instructions executable to perform a method of displaying an image on a display including a plurality of lines of display pixels, each display pixel being associated with a common electrode, the method comprising:
 applying a first signal to the common electrode associated with each of a plurality of display pixels in a first group of display pixels, the first group including one or more of the plurality of lines of display pixels, wherein the first signal is an alternating current signal; 
 scanning a first set of the lines of display pixels of the first group while not applying a second signal to the common electrode associated with each of a plurality of display pixels in a second group of display pixels, the second group including one or more of the plurality of lines of display pixels different from the first group, wherein the second signal is an alternating current signal; 
 applying the second signal to the common electrode associated with each of the plurality of display pixels in the second group; 
 scanning a second set of the lines of display pixels of the first group while the first and second signals are being applied; 
 discontinuing application of the first signal; and 
 scanning a third set of the lines of display pixels of the second group while the second signal is being applied. 
 
     
     
       15. The non-transitory computer-readable storage medium of  claim 14 , wherein scanning the third set of the lines includes scanning the third set of the lines prior to discontinuing application of the first signal, such that the third set of lines is scanned while the first and second signals are being applied. 
     
     
       16. The non-transitory computer-readable storage medium of  claim 15 , the method further comprising:
 scanning a fourth set of the lines of display pixels of the second group while the second signal is being applied and after discontinuation of the first signal. 
 
     
     
       17. The non-transitory computer-readable storage medium of  claim 15 , wherein the common electrode associated with each of the plurality of display pixels in the first group includes a first common electrode that is a contiguous layer of conductive material associated with a plurality of the display pixels. 
     
     
       18. The non-transitory computer-readable storage medium of  claim 15 , wherein the common electrode associated with each of the plurality of display pixels in the first group includes an individual common electrode associated with each of the display pixels, wherein a plurality of the individual common electrodes are electrically connected together. 
     
     
       19. The non-transitory computer-readable storage medium of  claim 18 , wherein all of the individual common electrodes associated with the display pixels in the first group are electrically connected together through a plurality of conductive lines within a plurality of stackups of the display pixels. 
     
     
       20. The non-transitory computer-readable storage medium of  claim 18 , wherein a first subset of the individual common electrodes are electrically connected together, a second subset of the individual common electrodes are electrically connected together, and the first and second subsets are electrically disconnected within a plurality of stackups of the display pixels. 
     
     
       21. The non-transitory computer-readable storage medium of  claim 15 , wherein the common electrode associated with the display pixels in the second group is electrically floating after discontinuing application of at least one of the first or second signal to the common electrode. 
     
     
       22. The non-transitory computer-readable storage medium of  claim 15 , wherein the common electrode associated with the display pixels in the second group is electrically connected to a fixed voltage after discontinuing application of at least one of the first or second signal to the common electrode. 
     
     
       23. The non-transitory computer-readable storage medium of  claim 15 , wherein applying the first and second signals occur during a display operation, the method further comprising:
 operating, during a touch sensing operation, the common electrodes associated with each of the display pixels in the first group as one of a drive line and a sense line, wherein operating the common electrodes as the drive line includes applying stimulation signals to the common electrodes, and operating the common electrodes as the sense line includes receiving sense signals from the common electrodes. 
 
     
     
       24. The non-transitory computer-readable storage medium of  claim 23 , further comprising:
 applying a third signal to the common electrode associated with each of a plurality of display pixels in a third group, wherein the third signal is an alternating current signal, the third signal being applied during the scanning of the first, second, and third sets of lines. 
 
     
     
       25. The non-transitory computer-readable storage medium of  claim 24 , wherein the third group includes the display pixels in the first, second, and third sets of lines. 
     
     
       26. The non-transitory computer-readable storage medium of  claim 24 , further comprising:
 operating, during the touch sensing operation, the common electrodes associated with each of the display pixels in the third group as the drive line, if the common electrodes associated with the first group are being operated as the sense line, and operating the common electrodes associated with the third group as the sense line, if the common electrodes associated with the first group are being operated as the drive line.

Description:
FIELD OF THE DISCLOSURE 
     This relates generally to driving common electrodes of display screens and touch screens, and more particularly, to a relay driving of multiple common electrode segments of display screens and touch screens. 
     BACKGROUND OF THE DISCLOSURE 
     Many types of display screens utilize a common electrode within the display panel. For example, liquid crystal displays (LCDs) can use a common electrode that spans the entire display to provide a common voltage to all of the display pixels. Common electrodes can be formed of, for example, a transparent conductor such as indium tin oxide (ITO). Pixel voltages can be applied to pixel electrodes in individual display pixels, for example, to create an electric field between the pixel electrode and the common electrode. In LCDs, the electric field created by a common electrode and a pixel electrode can be controlled to cause the liquid crystal of the display pixel to allow more or less light from a backlight to pass through the display pixel. Consequently, the luminance or brightness of each display pixel can be controlled. Likewise, many touch screens can utilize a common electrode within the display panel. 
     SUMMARY 
     Multiple Vcom segments of display screens can be driven in a relay fashion, such that the driving of different Vcom segments overlaps. For example, a Vcom signal can be applied to a first segment of Vcom, and lines of display pixels in the first segment can be scanned. When scanning nears the end of the first segment, a Vcom signal can be applied to the next segment of Vcom before scanning in the first segment ends. For example, when the second-to-the-last line of display pixels in a segment of Vcom is scanned, the next Vcom segment can be driven with a Vcom signal Likewise, when scanning in the next segment of Vcom begins, the Vcom signal can continue to be applied to the first segment of Vcom until a few lines of display pixels in the next segment have been scanned. In this way, for example, some visual artifacts may be reduced or eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1C  illustrate an example mobile telephone, an example media player, and an example personal computer that each include an example touch screen according to embodiments of the disclosure. 
         FIG. 2  illustrates an example display screen including multiple display pixels arranged in scan lines. 
         FIG. 3  illustrates an example display screen including multiple Vcom segments according to various embodiments. 
         FIG. 4  is a flowchart of an example method of scanning display screen according to various embodiments. 
         FIG. 5  illustrates an example scanning of a display screen at various times according to the example method of scanning shown in  FIG. 4 . 
         FIG. 6  illustrates an exploded perspective view of a portion of an example electrically controlled birefringence (ECB) LCD display screen according to various embodiments. 
         FIG. 7  illustrates an exploded perspective view of a portion of an example in-plane switching (IPS) LCD display screen according to various embodiments. 
         FIG. 8  is a block diagram of an example computing system according to various embodiments. 
         FIG. 9  illustrates example embodiments of sense lines, drive lines, and other example structures including Vcom segments of a touch screen according to various embodiments. 
         FIG. 10  illustrates a more detailed view of an example configuration of drive lines according to various embodiments. 
         FIG. 11  illustrates an example color filter glass design according to various embodiments. 
         FIG. 12  illustrates an example TFT design according to various embodiments. 
         FIG. 13  illustrates a example method of operating a touch screen according to various embodiments. 
         FIG. 14  illustrates example embodiments of sense lines and drive lines according to various embodiments. 
         FIG. 15  further illustrates example embodiments of sense lines and drive lines according to various embodiments. 
         FIG. 16  illustrates a example method of operating a touch screen 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. 
     The following description includes examples of driving multiple Vcom segments of display screens in a relay fashion, such that the driving of different Vcom segments overlaps. In some embodiments, a Vcom signal can be applied to a first segment of Vcom, and lines of display pixels in the first segment can be scanned. When scanning nears the end of the first segment, a Vcom signal can be applied to the next segment of Vcom before scanning in the first segment ends. When scanning in the next segment of Vcom begins, the Vcom signal can continue to be applied to the first segment of Vcom until a few lines of display pixels in the next segment have been scanned. In this way, for example, some visual artifacts may be reduced or eliminated. 
     Although various embodiments include “lines” of display pixels that are scanned to update a displayed image, the scanned lines of display pixels need not be strictly linear, but can include scanned groups of display pixels that are zig-zag, curved, or any group or subset of display pixels that is scanned to update a displayed image. 
       FIGS. 1A-1C  show example systems in which a display screen 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 . In some embodiments, display screens  124 ,  126 , and  128  can be touch screens that include touch sensing functionality based on, for example, mutual capacitance, as described in more detail below. 
       FIG. 2  illustrates an example display screen  200  including multiple display pixels  201  arranged in lines, such as a first scan line  203  and a second scan line  205 . Display screen  200  can include multiple gate lines  209 , with each gate line running through a scan line of display pixels  201 . Display screen  200  can also include multiple data lines  211 , with each data line addressing one of the display pixels in each scan line. Display screen  200  can also include a single common electrode (Vcom)  213  that spans all of the display pixels  201  of the display screen. Vcom  213  can be formed of, for example, a single sheet of transparent conductor, such as indium tin oxide (ITO). 
     A display driver  207  can include a gate line driver  215 , a Vcom driver  217 , and a data line driver  219 . Display driver  207  can display an image on display screen  200  by scanning a scan line to apply a pixel voltage to each display pixel  201  in the scan line, scanning a next scan line to apply the pixel voltages in the next scan line, and so forth. The pixel voltages can control, for example, the luminances of the display pixels. For example, in a liquid crystal display (LCD), the pixel voltage can control the liquid crystal of a display pixel to allow more or less light from a backlight to pass through the display pixel. 
     In one example scanning operation, Vcom driver  217  can apply a Vcom signal, such as an alternating current (AC) signal, to Vcom  213 . For example, the Vcom signal can be a square wave with a period equal to twice a scanning time of a single scan line. Initially, gate line driver  215  can switch pixel transistors of all display pixels  201  to an “off” state. Scanning can begin during the first half of the period of the Vcom signal, for example, when the Vcom signal is a positive voltage. Gate line driver  215  can switch pixel transistors of display pixels  201  in first scan line  203  to an “on” state by applying an appropriate gate line voltage to the gate line  209  of first scan line  203 . Data line driver  219  can apply data signals to data lines  211 , and with the pixel transistors of first scan line  203  in the “on” state, the pixel voltages of display pixels  201  in the first scan line can be set based on the data signals and the positive voltage of the Vcom signal. 
     The next scan line, e.g., second scan line  205 , can be scanned during the second half of the period of the Vcom signal, for example, when the Vcom signal is a negative voltage. Gate line driver  215  can switch “off” the pixel transistors of first scan line  203  and can switch “on” the pixel transistors of second scan line  205 . Data line driver  219  can apply data signals to data lines  211 , and with the pixel transistors in the “on” state, the pixel voltages of display pixels  201  in second scan line  203  can be set based on the data signals and the negative voltage of the Vcom signal. Scanning can continue with the application of pixel voltages to the scan lines occurring during alternating positive and negative Vcom voltages. 
     In example display screen  200 , a single Vcom  213  can be associated with all of the display pixels  201  in the display screen. Vcom driver  217  can drive Vcom  213 , i.e., an entire sheet of ITO spanning all of the display pixels in this example, throughout the scanning of all of the scan lines of the display screen. 
     An example operation of a display screen including Vcom segments will now be described in reference to  FIGS. 3-5 .  FIG. 3  illustrates an example display screen  300  including multiple Vcom segments  301  according to various embodiments. For example, display screen  300  can include  960  scan lines of display pixels and sixteen Vcom segments  301 , with each Vcom segment spanning sixty scan lines. Vcom drive lines  303  can connect each Vcom segment to a Vcom driver  305 . Multiple Vcom segments  301  can be used in place of the single Vcom of display screen  200  shown in  FIG. 2 , for example. Other structures of display screen  300 , such as gate lines, data lines, etc., can be similar to display screen  200 . 
       FIG. 4  is a flowchart of an example method of scanning display screen  300  according to various embodiments.  FIG. 5  illustrates the scanning of display screen  300  at various times according to the example method of scanning shown in  FIG. 4 . Referring to  FIGS. 4-5 , Vcom driver  305  can apply ( 401 ) a first Vcom signal to a first Vcom segment  501  associated with each of the display pixels in first sixty scan lines. The first Vcom signal can be an AC signal, such as a square wave. A first set of the sixty scan lines associated with first Vcom segment  501  can be scanned ( 402 ). The first set of scan lines can include, for example, the first  58  scan lines associated with first Vcom segment  501 . Scanning each scan line can be performed, e.g., as described above in reference to display screen  200  of  FIG. 2 . 
       FIG. 5  illustrates display screen  300  at a Time  1 , during which a scan line  503  of the first set of scan lines, e.g., the 1st through 58th scan lines of display screen  300 , is being scanned. During the scanning of the first set of scan lines, Vcom driver  305  can apply no Vcom signal to the other Vcom segments, including a second Vcom segment  505  and a third Vcom segment  507 . For the purpose of clarity, diagonal hatching through a Vcom segment shown in  FIG. 5  signifies that no Vcom signal is being applied at that time to the Vcom segment. Next, Vcom driver  305  can apply ( 403 ) a second Vcom signal to second Vcom segment  505 , and a second set, e.g., the last two scan lines, of the sixty scan lines associate with first Vcom segment  501  can be scanned ( 404 ). Thus, the last two scan lines associated with first Vcom segment  501  can be scanned while the first and second Vcom signals are being applied to first Vcom segment  501  and second Vcom segment  505 , respectively. In other words, the second Vcom signal can be applied to second Vcom segment  505  during a time in which scan lines associated with first Vcom segment are being scanned. This overlap of driving second Vcom segment  505  during scanning of scan lines of first Vcom segment  501 , for example, may help reduce or eliminate some visual artifacts. 
       FIG. 5  illustrates display screen  300  at a Time  2 , during which a scan line  509  of the second set of scan lines is being scanned. During the scanning of the second set of scan lines, e.g. the 59th and 60th scan lines of display screen  300 , Vcom driver  305  can apply no Vcom signal to Vcom segments other than first Vcom segment  501  and second Vcom segment  505 . Next, a third set of scan lines, e.g., the 1st and 2nd scan lines of second Vcom segment  505  (i.e., the 61st and 62nd scan lines of display screen  300 ), can be scanned ( 405 ). 
       FIG. 5  illustrates display screen  300  at a Time  3 , during which a scan line  511  of the third set of scan lines is being scanned prior to discontinuing the application of the first Vcom signal to first Vcom segment  501 . During the scanning of the third set of scan lines, e.g. the 61st and 62nd scan lines of display screen  300 , Vcom driver  305  can apply no Vcom signal to Vcom segments other than first Vcom segment  501  and second Vcom segment  505 . Next, Vcom driver  305  can discontinue ( 406 ) applying the first Vcom signal to first Vcom segment  501 . In some embodiments, the first Vcom signal can be discontinued prior to scanning of scan lines of second Vcom segment  505 . However, in the example embodiment of  FIGS. 4-5 , the first Vcom signal can be applied to first Vcom segment  501  while the third set of scan lines of second Vcom segment  505  is scanned, such that the third set of scan lines is scanned while the first and second Vcom signals are being applied. This overlap of driving first Vcom segment  501  during scanning of scan lines of second Vcom segment  505 , for example, may further help reduce or eliminate some visual artifacts. 
     Next, a fourth set of scan lines, e.g., the 3rd through 58th scan lines of second Vcom segment  505  (i.e., the 63rd though 118th scan lines of display screen  300 ), can be scanned ( 407 ) while the second Vcom signal is being applied and the first Vcom signal is not being applied.  FIG. 5  illustrates display screen  300  at a Time  4 , during which a scan line  513  of the fourth set of scan lines is being scanned. During the scanning of the fourth set of scan lines, Vcom driver  305  can apply no Vcom signal to Vcom segments other than second Vcom segment  505 . The method of scanning can continue ( 408 ) as described above until the entire display screen has been scanned. 
     In some embodiments, scanning of each scan line can be performed in 16 microseconds, for example. In this case, an overlap of the first and second Vcom signals can be 64 microseconds in the example method of  FIGS. 4-5  with the second and third sets of scan lines each including two scan lines. In other words, the first and second Vcom signals can be applied concurrently during scanning of four scan lines, with application of the second Vcom signal beginning two scan lines prior to the start of scanning in second Vcom segment  505 , and application of the first Vcom signal discontinuing two scan lines after the end of scanning in first Vcom segment  501 . 
     Although sequential scanning of scan lines is described in example embodiments, one skilled in the art would understand that other methods of scanning could be used, such as scanning every other scan line. Furthermore, although example embodiments describe that the second and third sets can include scan lines adjacent to the next (or previous) Vcom segment, it should be understood that scan lines other than the scan lines adjacent to the next (or previous) Vcom segment can be used. 
       FIGS. 6 and 7  illustrate various example structures and configurations of display screens according to embodiments of the disclosure.  FIG. 6  illustrates an exploded perspective view of a portion of an example electrically controlled birefringence (ECB) LCD display screen  600  according to various embodiments. Display screen  600  can include a color filter glass  601 , with Vcom segments  603  and Vcom drive lines  605  formed thereon. A thin-film transistor (TFT) glass  607  can include a gate driver  609  that drives gate line  611 , data lines for blue  613 , green  615 , and red  617  data, and pixel electrodes  619 . Liquid crystal cells  621  can be disposed between pixel electrodes  619  and Vcom segments  603 , such that an electric field can be generated between a pixel electrode and an associated Vcom segment. In this example embodiment, gate driver  609  can scan lines of display pixels associated with gate lines  611 , and a Vcom driver (not shown) can drive Vcom segments  603  according to the method of  FIGS. 4-5 , for example. 
       FIG. 7  illustrates an exploded perspective view of a portion of an example in-plane switching (IPS) LCD display screen  700  according to various embodiments. Display screen  700  can include a color filter glass  701 . A TFT glass  703  can include individual Vcoms  705  associated with each display pixel, Vcom drive lines  707 , a gate driver  709  that drive gate line  711 , data lines for blue  713 , green  715 , and red  717  data, and pixel electrodes  719 . Vcom drive lines  707  can be conductive lines that connect together the Vcom  705  to form Vcom segment regions  723  that can function as Vcom segments. Liquid crystal cells  721  can be disposed over pixel electrodes  719  and Vcom  703 , such that an electric field can be generated between a pixel electrode and an associated Vcom. In this example embodiment, gate driver  709  can scan lines of display pixels associated with gate lines  711 , and a Vcom driver (not shown) can drive Vcom segment regions  723 , which can correspondingly drive individual Vcom  705 , according to the method of  FIGS. 4-5 , for example. 
     In some embodiments, a display screen can include touch sensing functionality, i.e., a touch screen. For example, a mutual capacitance based touch system can include drive regions and sense regions, such as drive lines and sense lines. Drive lines can be formed in rows while sense lines can be formed in columns (e.g., orthogonal), for example. Touch pixels can be formed at the intersections of the rows and columns. 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, capacitive touch, etc. 
       FIG. 8  is a block diagram of an example computing system  800  that illustrates one implementation of an example touch screen  820  according to embodiments of the disclosure. Computing system  800  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  800  can include a touch sensing system including one or more touch processors  802 , peripherals  804 , a touch controller  806 , and touch sensing circuitry (described in more detail below). Peripherals  804  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  806  can include, but is not limited to, one or more sense channels  808 , channel scan logic  810  and driver logic  814 . Channel scan logic  810  can access RAM  812 , autonomously read data from the sense channels and provide control for the sense channels. In addition, channel scan logic  810  can control driver logic  814  to generate stimulation signals  816  at various frequencies and phases that can be selectively applied to drive lines of the touch sensing circuitry of touch screen  820 , as described in more detail below. In some embodiments, touch controller  806 , touch processor  802  and peripherals  804  can be integrated into a single application specific integrated circuit (ASIC). 
     Computing system  800  can also include a host processor  828  for receiving outputs from touch processor  802  and performing actions based on the outputs. For example, host processor  828  can be connected to program storage  832  and a display controller, such as an LCD driver  834 . Host processor  828  can use LCD driver  834  to generate an image on touch screen  820 , such as an image of a user interface (UI), and can use touch processor  802  and touch controller  806  to detect a touch on or near touch screen  820 , such a touch input to the displayed UI. The touch input can be used by computer programs stored in program storage  832  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  828  can also perform additional functions that may not be related to touch processing. 
     Touch screen  820  can include touch sensing circuitry that can include a capacitive sensing medium having a plurality of drive lines  822  and a plurality of sense lines  823 . It should be noted that the term “conductive lines” is a 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, and multiple electrically conductive circuit elements that can be electrically connected to form a single electrically conductive pathway. Drive lines  822  can be driven by stimulation signals  816  from driver logic  814  through drive interfaces  824   a  and  824   b , and resulting sense signals  817  generated in sense lines  823  can be transmitted through a sense interface  825  to sense channels  808  (also referred to as an event detection and demodulation circuit) in touch controller  806 . 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  826  and  827 . This way of understanding can be particularly useful when touch screen  820  is viewed as capturing an “image” of touch. In other words, after touch controller  806  has determined an amount of touch 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). 
       FIG. 9  illustrates example embodiments of sense lines, drive lines, and other example structures including Vcom segments of a touch screen according to various embodiments.  FIG. 9  shows a more detailed view of a lower left hand portion of a touch screen  920 , which can be one example embodiment of touch screen  820  as viewed along line “A” shown in  FIG. 8 . Although reference numerals of elements of  FIG. 8  are used to describe the elements of touch screen  920 , it should be understood that the elements of touch screen  920  are merely one example embodiment of the elements shown in  FIG. 8 . In the example embodiment shown in  FIG. 9 , each sense line  823  can include multiple conductive wires  901 , e.g., five conductive wires in this example embodiment. Conductive wires  901  can be disposed on the underside of a color filter glass  903 , which includes a plurality of color filters  905 . In this example embodiment, color filters  905  each include three colors, blue (B), green (G), and red (R), such as in an RGB display. Each conductive wire  901  can be positioned between two columns of color filters  905 . In this example, the space between the columns of the color filters can be widened to accommodate the conductive wire. The five conductive wires  901  of each sense line  823  are connected to a contact pad  907  that conductively connects the conductive wires of the sense line and allows each group of five conductive wires to operate as a single sense line. Contact pads  907  can be electrically connected to, for example, sense channels  808  of touch controller  806  shown in  FIG. 8 , so that sense signals  817  received by each sense line  823  can be processed by the touch controller. 
       FIG. 9  also shows a TFT glass  909 , on which can be formed circuit elements  911 . 
     Circuit elements  911  can be, for example, multi-function circuit elements that operate as part of the display circuitry of the touch screen and also as part of the touch sensing circuitry of the touch screen. In some embodiments, circuit elements  911  can be single-function circuit elements that operate only as part of the touch sensing system. In addition to circuit elements  911 , other circuit elements (not shown) can be formed on TFT glass  909 , such as transistors, capacitors, conductive vias, data lines, gate lines, etc. Circuit elements  911  and the other circuit elements formed on TFT glass  909  can operate together to perform various display functionality required for the type of display technology used by touch screen  920 , as one skilled in the art would understand. The circuit elements can include, for example, elements that can exist in conventional LCD displays. 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. 
     Some of the circuit elements  911  can be electrically connected together to form drive lines  822 . The example configurations of sense lines  823  and drive lines  822  shown in  FIG. 9  can be laid out as shown in  FIG. 8  as an overlapping orthogonal grid to form touch pixels  826  and  827 , for example. 
       FIG. 9  also shows a pixel material  915  disposed between TFT glass  909  and color filter glass  903 . Pixel material  915  can, for example, be divided among each display pixel of the touch screen. Pixel material  915  can be a material that, when operated on by the display circuitry of touch screen  920 , can generate or control an amount, color, etc., of light produced by each display pixel. For example, in an LCD touch screen, pixel material  915  can be liquid crystal, with each display pixel including a cell of liquid crystal. In this case, for example, various methods exist for operating liquid crystal in a display operation to control the amount of light emanating from each display pixel, e.g., applying an electric field in a particular direction depending on the type of LCD technology employed by the touch screen. In an in-plane switching (IPS) LCD display, for example, electrical fields between pixel electrodes and common electrodes (Vcom) disposed on the same side of the liquid crystal can operate on the liquid crystal to control the amount of light from a backlight that passes through the display pixel. One skilled in the art would understand that various pixel materials can be used, depending on the type of display technology of the touch screen. 
       FIG. 10  illustrates a more detailed view of an example configuration of drive lines  822  according to various embodiments. In this example embodiment, circuit elements  911  can include common electrodes (Vcom)  1001 . Common electrodes  1001  can be operated as multi-function circuit elements that can operate as part of the display circuitry in a display operation and can operate as part of the touch sensing circuitry in a touch sensing operation of the touch screen. Common electrodes  1001  can be electrically connected together with conductive lines  1003  to form Vcom segment regions  1005  that can operate as drive lines  822  during a touch sensing operation, and that can operate as Vcom segments during a display operation. In this example embodiment, common electrodes in a particular functional region can be physically connected with fixed conductive lines. In other words, the common electrodes in each region can be permanently connected through the physical design of the touch screen, for example, grouped together to form drive lines. Grouping multi-function circuit elements of display pixels can include operating the multi-function circuit elements of the display pixels together to perform a common function of the group. Grouping into functional regions may be accomplished through one or a combination of approaches, for example, the structural configuration of the system (e.g., physical breaks and bypasses, voltage line configurations), the operational configuration of the system (e.g., switching circuit elements on/off, changing voltage levels and/or signals on voltage lines), etc. 
     Stimulation signals can be applied to drive lines  822  through Vcom drive lines  1007 . For example, Vcom drive lines  1007  can be electrically connected to driver logic  814 , which can provide the stimulation signals during the touch sensing operation, and can provide Vcom signals during the display operation. For example, during the display operation, driver logic  814  can perform the method of operating Vcom segments to scan lines of display pixels as described above with reference to  FIGS. 4-5 . 
     In the example shown in  FIG. 10 , each common electrode (Vcom)  1001  can serve as a multi-function circuit element that can operate as display circuitry of the display system of touch screen  920  and can also operate as touch sensing circuitry of the touch sensing system. In this example, each common electrode  1001  can operate as a common electrode of the display circuitry of the touch screen, and can also operate together when grouped with other common electrodes as touch sensing circuitry of the touch screen. For example, a group of common electrodes  1001  can operate together as a part of a drive line of the touch sensing circuitry during the touch sensing operation. Other circuit elements of touch screen  920  can form part of the touch sensing circuitry by, for example, electrically connecting together common electrodes  1001  of a region, switching electrical connections, etc. Each display pixel can include a common electrode  1001 , which can be a circuit element 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, that can operate as part of the display system to display an image. 
     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 embodiments, 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 embodiments, all of the circuit elements of the display pixel stackups may be single-function circuit elements. 
       FIGS. 11-12  illustrate an example color filter glass design and an example TFT design, respectively, according to various embodiments.  FIG. 11  includes an example configuration of multiple sense lines  823 , each including multiple conductive wires such as conductive wires  901 , connected to multiple contact pads, such as contact pad  911 . For the sake of clarity, individual color filters are not shown in  FIG. 11 . In this example embodiment, conductive wires  901  and contact pads  907  can be formed on color filter glass  903  by, for example, physical vapor deposition (PVD) or other techniques known to those skilled in the art. 
       FIG. 12  illustrates an example TFT glass according to various example embodiments. TFT glass  1201  can include various touch sensing circuitry and display circuitry. Touch sensing circuitry can include, for example, drive lines  822 . In this example embodiment, each drive line  822  can include multiple Vcom drive rows  1203 . In this example embodiment, each Vcom drive row  1203  in a drive line  822  can be connected to a single conductive contact pad  1205  on the left side of the TFT glass, and connected to a single contact pad  1205  on the right side of TFT glass. Contact pads  1205  can be connected through Vcom drive lines  1207  through touch controller  806  through a touch flex circuit  1209 . In this way, for example, multiple Vcom drive rows  1203  can be driven together as a single drive line  822  during a touch sensing operation, and driven together as a Vcom segment during a display operation. Touch flex circuit  1209  can also be connected to sense signal lines  1213 , which can be connected to contact pads  907  on the color filter glass through conductive paste  1215 . 
       FIG. 13  illustrates an example method of operating a touch screen including Vcom segments as described with respect to  FIGS. 9-12 . In a first display operation, touch screen  920  can be operated, for example, as in the method described with respect to  FIGS. 4-5  to display an image. In particular, driver logic  814  can apply a first Vcom signal  1301  to a first Vcom segment  1303 , LCD driver  834  can scan through a first set of scan lines associated with the first Vcom segment, the driver logic can apply a second Vcom signal  1305  to a second Vcom segment  1307 , the LCD driver can scan a second set of scan lines associated with the first Vcom segment, the LCD driver can scan a third set of scan lines associated with the second Vcom segment (such that there is an overlap  1309  of the application of the first and second Vcom signals), the driver logic can discontinue applying the first Vcom signal, etc. The method can continue through the application of a 16th Vcom signal  1311  to a 16th Vcom segment  1313 . 
     In a first touch sensing operation, driver logic can apply stimulation signals  1315  to all or some of the Vcom segments, thereby operating the Vcom segments as drive lines of the touch sensing system. Sense signals can be received on sense lines  823  and processed by touch controller  806 . In some embodiments, the functionality of driver logic  814  and LCD driver  834  can be integrated into a single component. 
       FIGS. 14-15  illustrate other example embodiments of sense lines and drive lines including Vcom segments according to various embodiments. Although reference numerals of elements of  FIG. 8  are used to describe the elements of shown in  FIGS. 14-15 , it should be understood that the elements shown in  FIGS. 14-15  are merely one example embodiment of the elements shown in  FIG. 8 . In the example embodiment shown in  FIGS. 14-15 , each drive line  822  and sense line  823  of a touch screen  1420  can include multiple circuit elements in the display pixel stackups, such as individual Vcoms associated with each of the display pixels. As shown in  FIG. 14 , each sense line  823  can be formed of a sense Vcom segment  1402 , and each drive line  822  can be formed of multiple drive Vcom segments  1401  that can be electrically connected by drive line links  1403  at connections  1405 . Drive line links  1403  are not electrically connected to sense Vcom segments  1402 , rather, the drive line links can bypass the sense Vcom segments through bypasses  1407 . Drive lines  822  and sense lines  823  can interact capacitively to form touch pixels such as touch pixels  826  and  827 . Drive lines  822  (i.e., drive Vcom segments  1401  and corresponding drive line links  1403 ) and sense lines  823  can be formed of electrical circuit elements in touch screen  820 , including individual Vcoms of the display pixels. In the example configuration of  FIG. 14 , each of touch pixels  826  and  827  can include a portion of one drive Vcom segment  1401 , a portion of a sense Vcom segment  1402 , and a portion of another drive Vcom segment  1401 . For example, touch pixel  826  can include a right-half portion  1409  of a drive Vcom segment on one side of a portion  1411  of a sense Vcom segment, and a left-half portion  1413  of a drive Vcom segment on the opposite side of portion  311  of the sense Vcom segment. 
     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.  FIG. 15  illustrates a more detailed view of the configuration of drive Vcom segments  1401  and sense Vcom segments  1402 , showing each of the segments including multiple individual Vcoms  1501 . For the sake of clarity,  FIG. 15  omits drive line links  1403  and other elements of touch screen  1420 . 
       FIG. 16  illustrates a example method of operating a touch screen including Vcom segments as described with respect to FIGS.  8  and  14 - 15 . In a first display operation, driver logic  814  can apply a sense Vcom signal to all segments  1617  of sense Vcom segments  1402 , the driver logic can apply a first Vcom signal  1601  to a first set  1603  of drive Vcom segments  1401  (i.e., a first drive line), LCD driver  834  can scan through a first set of scan lines associated with the first set of Vcom drive segments (it is noted that the scan lines also run through corresponding portions of sense Vcom segments  1402 ), the driver logic can apply a second Vcom signal  1605  to a second set  1607  of the drive Vcom segments, the LCD driver can scan a second set of scan lines associated with the first set of the drive Vcom segments, the LCD driver can scan a third set of scan lines associated with the second set of drive Vcom segments (such that there is an overlap  1609  of the application of the first and second Vcom signals), the driver logic can discontinue applying the first Vcom signal, etc. The method can continue through the application of a 16th Vcom signal  1311  to a 16th set  1613  of drive Vcom segments, and application of sense Vcom signal  1615  can be discontinued. 
     In a first touch sensing operation, driver logic can apply stimulation signals  1619  to all or some of the sets of drive Vcom segments, thereby operating the sets of drive Vcom segments as drive lines of the touch sensing system. Sense signals can be received on sense Vcom segments  1402  and processed by touch controller  806 . In some embodiments, the functionality of driver logic  814  and LCD driver  834  can be integrated into a single component. 
     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, one or more of the functions of computing system  800  described above can be performed by firmware stored in memory (e.g. one of the peripherals  804  in  FIG. 8 ) and executed by touch processor  802 , or stored in program storage  832  and executed by host processor  828 . The firmware can also be stored and/or transported within any computer-readable 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 “computer-readable medium” can be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The computer readable 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 readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     Example embodiments may be described herein with reference to a Cartesian coordinate system in which the x-direction and the y-direction can be equated to the horizontal direction and the vertical direction, respectively. However, one skilled in the art will understand that reference to a particular coordinate system is simply for the purpose of clarity, and does not limit the direction of the elements to a particular direction or a particular coordinate system. Furthermore, 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. 
     Although various embodiments are described with respect to display pixels, one skilled in the art would understand that the term display pixels can be used interchangeably with the term display sub-pixels in embodiments in which display pixels are divided into sub-pixels. For example, some embodiments directed to RGB displays can include display pixels divided into red, green, and blue sub-pixels. In other words, in some embodiments, each sub-pixel 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. One skilled in the art would understand that other types of touch screen could be used. For example, in some embodiments, 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, in which each structure shown in the figures as a sub-pixel can be a pixel of a single color.

Metadata:
Filing Date: 20101222
Publication Date: 20131126
Grant Date: 20131126
Priority Date: 20101222
Inventors: CHANG SHIH CHANG
BAE HOPIL
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13306", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13306", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04184", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46316035