PATENT DOCUMENT

Publication Number: US-9336723-B2
Application Number: US-201313766376-A
Country: US
Kind Code: B2

Title: In-cell touch for LED

Abstract:
A touch screen having touch circuitry integrated into a display pixel stackup. The touch screen can include a transistor layer, an LED layer and a first layer. The first layer can operate as an LED cathode during a display phase and as touch circuitry during a touch sensing phase. The transistor layer can be at least partially utilized for transitioning between the display phase and the touch sensing phase. The touch screen can be fabricated to reduce or eliminate damage to the LED layer.

Claims:
The invention claimed is: 
     
       1. A touch screen comprising:
 a transistor layer including a first transistor and a second transistor connected to the first transistor; 
 a first layer disposed over the transistor layer and configured to operate as a light-emitting diode (LED) cathode during a display phase and as touch circuitry during a touch sensing phase; 
 an LED layer disposed between the transistor layer and the first layer, wherein the first transistor is connected to the LED layer and a power supply line; and 
 a gate voltage line connected to a gate terminal of the second transistor, wherein during the display phase, the gate voltage line is set to a first voltage, which causes the second transistor to turn on, and during the touch sensing phase, the gate voltage line is set to a second voltage, which causes the second transistor to turn off. 
 
     
     
       2. The touch screen of  claim 1 , wherein the LED layer comprises an organic light-emitting diode (OLED) layer. 
     
     
       3. The touch screen of  claim 1 , wherein during the display phase, the power supply line voltage is set to a first power supply voltage, and during the touch sensing phase, the power supply line voltage is set to a second power supply voltage, different than the first power supply voltage. 
     
     
       4. The touch screen of  claim 3 , wherein the first power supply voltage causes the LED layer to emit light, and the second power supply voltage causes the LED layer to not emit light. 
     
     
       5. The touch screen of  claim 1 , wherein the first layer comprises a plurality of drive lines and a plurality of sense lines. 
     
     
       6. The touch screen of  claim 5 , wherein a drive line comprises:
 a first drive line segment; and 
 a second drive line segment electrically connected to the first drive line segment by a drive line connection. 
 
     
     
       7. The touch screen of  claim 6 , wherein the drive line connection is disposed over the first layer. 
     
     
       8. The touch screen of  claim 6 , wherein the drive line connection is disposed under the first layer. 
     
     
       9. The touch screen of  claim 1 , wherein the second transistor is connected to the first transistor in series. 
     
     
       10. The touch screen of  claim 1 , wherein the first voltage causes the LED layer to emit light, and the second voltage causes the LED layer to not emit light. 
     
     
       11. A method for operating a touch screen comprising:
 operating, during a display phase, a first layer as a cathode of a light-emitting diode (LED) layer by setting a voltage of a gate voltage line to a first voltage, the gate voltage line connected to a gate terminal of a second transistor that is connected to a first transistor, the first transistor connected to the LED layer and a power supply line, and the first voltage causing the second transistor to turn on; and 
 operating, during a touch sensing phase, the first layer as touch circuitry by setting the voltage of the gate voltage line to a second voltage, the second voltage causing the second transistor to turn off. 
 
     
     
       12. The method of  claim 11 , wherein:
 operating the first layer as the cathode of the LED layer comprises setting a voltage of the power supply line connected to a transistor to a first power supply voltage that causes the LED layer to emit light, and 
 operating the first layer as the touch circuitry comprises setting the voltage of the power supply line to a second power supply voltage, different from the first power supply voltage, that causes the LED layer to not emit light. 
 
     
     
       13. The method of  claim 11 , wherein operating the first layer as the touch circuitry comprises:
 operating the first layer as a plurality of drive line segments and a plurality of sense lines; and 
 electrically connecting a first drive line segment to a second drive line segment using a drive line connection. 
 
     
     
       14. The method of  claim 13 , wherein the drive line connection is disposed over the first layer. 
     
     
       15. The method of  claim 13 , wherein the drive line connection is disposed under the first layer. 
     
     
       16. The method of  claim 11 , wherein the second transistor is connected to the first transistor in series. 
     
     
       17. The method of  claim 11 , wherein the first voltage causes the LED layer to emit light, and the second voltage further the LED layer to not emit light.

Description:
FIELD OF THE DISCLOSURE 
     This relates generally to touch sensing, and more specifically to integrating touch circuitry into a Light-Emitting Diode (LED) pixel stackup. 
     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 Light-Emitting Diode (LED) display (for example, an Organic Light-Emitting Diode display (OLED) display) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. OLED displays are becoming more widespread with advances in OLED technology. 
     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 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 LED or OLED displays to form a touch screen (on-cell touch), as described above. However, integrating touch circuitry into an LED or OLED display pixel stackup (i.e., the stacked material layers forming the LED or OLED display pixels) can be desired (in-cell touch). 
     SUMMARY OF THE DISCLOSURE 
     The following description includes examples of integrating touch circuitry into an LED display pixel stackup of a touch screen device. The touch screen can include a transistor layer, an LED layer and a first layer that can be configured to operate as an LED cathode during a display phase and as touch circuitry during a touch sensing phase. The transistor layer can be at least partially utilized for transitioning between the display phase and the touch sensing phase. Furthermore, the touch screen can be fabricated in such a way as to reduce or eliminate damage to the LED layer during fabrication. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates an example mobile telephone that includes a touch screen. 
         FIG. 1B  illustrates an example digital media player that includes a touch screen. 
         FIG. 1C  illustrates an example personal computer that includes a touch screen. 
         FIG. 2  is a block diagram of an example computing system that illustrates one implementation of an example touch screen according to examples of the disclosure. 
         FIG. 3A  is a more detailed view of a touch screen showing an example configuration of drive lines and sense lines according to examples of the disclosure. 
         FIG. 3B  is a more detailed view of a touch screen showing another example configuration of drive lines and sense lines according to examples of the disclosure. 
         FIG. 4  illustrates an example configuration in which common electrodes can form portions of the touch sensing circuitry of a touch sensing system. 
         FIG. 5  is a three-dimensional illustration of an exploded view (expanded in the z-direction) of example display pixel stackups showing some of the elements within the pixel stackups of an example integrated touch screen. 
         FIG. 6  shows partial circuit diagrams of some of the touch sensing circuitry within display pixels in a drive region segment and a sense region of an example touch screen according to examples of the disclosure. 
         FIG. 7A  illustrates an exemplary AMOLED pixel circuit that can be used in a regular top emission OLED display. 
         FIG. 7B  illustrates another exemplary AMOLED pixel circuit that can be used in a regular top emission OLED display. 
         FIG. 7C  illustrates an exemplary AMOLED pixel circuit that can be used in an inverted OLED display. 
         FIGS. 8A and 8B  illustrate an exemplary AMOLED pixel circuit configuration and operation for turning on and off an OLED element during touch sensing and display phases of the touch screen of the disclosure. 
         FIGS. 9A-9D  illustrate further exemplary AMOLED pixel circuit configurations and operations for turning on and off an OLED element during touch sensing and display phases of the touch screen of this disclosure. 
         FIG. 10  illustrates an exemplary top emission OLED material stack according to examples of the disclosure. 
         FIGS. 11A and 11B-1 through 11B-5  illustrate an exemplary process for patterning the cathode layer according to examples of the disclosure. 
         FIGS. 12A and 12B-1 through 12B-5  illustrate another exemplary process for patterning the cathode layer according to examples of the disclosure. 
         FIGS. 13A and 13B-1 through 13B-6  illustrate another exemplary process for patterning the cathode layer according to examples of the disclosure. 
         FIGS. 14A and 14B  illustrate an exemplary way of lowering the sheet resistance of the cathode layer according to examples of the disclosure. 
         FIGS. 15A and 15B-1 through 15B-6  illustrate an exemplary process for forming a drive line connection over OLED layers according to examples of the disclosure. 
         FIGS. 16A-1 through 16A-3 and 16B-1 through 16B-3  illustrate an exemplary process for performing shadow mask deposition of the cathode layer according to examples of this disclosure. 
         FIGS. 17A-1 through 17A-2 and 17B-1 through 17B-3  illustrate an exemplary process for performing laser ablation to form drive and sense segments according to examples of the disclosure. 
         FIGS. 18A through 18C and 18D-1 through 18D-3  illustrate an exemplary process for modifying the distance between adjacent OLED emission layers according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of examples, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the disclosed examples. 
     Many types of input devices are presently available for performing operations in a computing system. 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 Light-Emitting Diode (LED) display (for example, an Organic Light-Emitting Diode display (OLED) display) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. OLED displays are becoming more widespread with advances in OLED technology. 
     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 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 LED or OLED displays to form a touch screen (on-cell touch), as described above. However, integrating touch circuitry into an LED or OLED display pixel stackup (i.e., the stacked material layers forming the LED or OLED display pixels) can be desired (in-cell touch). 
       FIGS. 1A-1C  show example systems in which a touch screen according to examples of the disclosure may be implemented.  FIG. 1A  illustrates an example mobile telephone  136  that includes a touch screen  124 .  FIG. 1B  illustrates an example digital media player  140  that includes a touch screen  126 .  FIG. 1C  illustrates an example personal computer  144  that includes a touch screen  128 . Although not shown in the figures, the personal computer  144  can also be a tablet computer or a desktop computer with a touch-sensitive display. Touch screens  124 ,  126 , and  128  may 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 (touch node) 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 (touch nodes) can be formed at the intersections or adjacencies (in single layer configurations) 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 examples, a touch screen can be multi-touch, single touch, projection scan, full-imaging multi-touch, or any capacitive touch. 
       FIG. 2  is a block diagram of an example computing system  200  that illustrates one implementation of an example touch screen  220  according to examples 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/or phases that can be selectively applied to drive regions of the touch sensing circuitry of touch screen  220 , as described in more detail below. In some examples, touch controller  206 , touch processor  202  and peripherals  204  can be integrated into a single application specific integrated circuit (ASIC). 
     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 Active-Matrix Organic Light-Emitting Diode (AMOLED) driver  234 . It is understood that although the examples of the disclosure are described with reference to AMOLED displays, the scope of the disclosure is not so limited and can extend to other types of LED displays such as Passive-Matrix Organic Light-Emitting Diode (PMOLED) displays. 
     Host processor  228  can use AMOLED 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 as a touch input to the displayed UI. The touch input can be used by computer programs stored in program storage  232  to perform actions that can include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device connected to the host device, answering a telephone call, placing a telephone call, terminating a telephone call, changing the volume or audio settings, storing information related to telephone communications such as addresses, frequently dialed numbers, received calls, missed calls, logging onto a computer or a computer network, permitting authorized individuals access to restricted areas of the computer or computer network, loading a user profile associated with a user&#39;s preferred arrangement of the computer desktop, permitting access to web content, launching a particular program, encrypting or decoding a message, and/or the like. Host processor  228  can also perform additional functions that may not be related to touch processing. 
     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 examples, touch screen  220  can be an integrated touch screen in which touch sensing circuit elements of the touch sensing system can be integrated into the display pixel stackups of a display. An example integrated touch screen in which examples of the disclosure can be implemented will now be described with reference to  FIGS. 3-6 .  FIG. 3A  is a more detailed view of touch screen  220  showing an example configuration of drive lines  222  and sense lines  223  according to examples of the disclosure. As shown in  FIG. 3A , each drive line  222  can be formed of one or more drive line segments  301  that can be electrically connected by drive line links  303  at connections  305 . Drive line links  303  are not electrically connected to sense lines  223 , rather, the drive line links can bypass the sense lines through bypasses  307 . Drive lines  222  and sense lines  223  can interact capacitively to form touch pixels such as touch pixels  226  and  227 . Drive lines  222  (i.e., drive line segments  301  and corresponding drive line links  303 ) and sense lines  223  can be formed of electrical circuit elements in touch screen  220 . In the example configuration of  FIG. 3A , each of touch pixels  226  and  227  can include a portion of one drive line segment  301 , a portion of a sense line  223 , and a portion of another drive line segment. For example, touch pixel  226  can include a right-half portion  309  of a drive line segment  301  on one side of a portion  311  of a sense line  223 , and a left-half portion  313  of a drive line segment on the opposite side of portion  311  of the sense line. 
       FIG. 3B  is a more detailed view of touch screen  220  showing another example configuration of drive lines  222  and sense lines  223  according to examples of the disclosure. As shown in  FIG. 3B , each sense line  223  can be formed of one or more sense line segments  313  that can be electrically connected by sense line links  315  at connections  317 . Sense line links  315  are not electrically connected to drive lines  222 , rather, the sense line links can bypass the drive lines through bypasses  319 . Drive lines  222  and sense lines  223  can interact capacitively to form touch pixels such as touch pixels  226  and  227 . Drive lines  222  and sense lines  223  (i.e., sense line segments  315  and corresponding sense line links  315 ) can be formed of electrical circuit elements in touch screen  220 . In the example of  FIG. 3B , each of touch pixels  226  and  227  can include a portion of a drive line  222  and a sense line segment  313 . For example, touch pixel  226  can include a portion  321  of a drive line  222  and sense line segment  323 . For ease of description, the examples of the disclosure will be described using the example configuration of  FIG. 3A , although it is understood that the examples of the disclosure are not limited to such a configuration. 
     The circuit elements in touch screen  220  can include, for example, elements that can exist in AMOLED displays, as described above. It is noted that circuit elements are not limited to whole circuit components, such as a whole capacitor, a whole transistor, etc., but can include portions of circuitry, such as only one of the two plates of a parallel plate capacitor.  FIG. 4  illustrates an example configuration in which common electrodes  401  can form portions of the touch sensing circuitry of a touch sensing system. Each display pixel  407  can include a portion of a common electrode  401 , which is 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 AMOLED displays that can operate as part of the display system to display an image. 
     In the example shown in  FIG. 4 , each common electrode  401  can serve as a multi-function circuit element that can operate as display circuitry of the display system of touch screen  220  and can also operate as touch sensing circuitry of the touch sensing system. In this example, each common electrode  401  can operate as a common electrode of the display circuitry of the touch screen  220 , and can also operate together when grouped with other common electrodes as touch sensing circuitry of the touch screen. For example, a common electrode  401  can operate as a capacitive part of a drive line (i.e., a drive line segment  403 ) or as a capacitive sense line  405  of the touch sensing circuitry during the touch sensing phase. Other circuit elements of touch screen  220  can form part of the touch sensing circuitry by, for example, switching electrical connections, etc. In general, each of the touch sensing circuit elements may be either a multi-function circuit element that can form part of the touch sensing circuitry and can perform one or more other functions, such as forming part of the display circuitry, or may be a single-function circuit element that can operate as touch sensing circuitry only. Similarly, each of the display circuit elements may be either a multi-function circuit element that can operate as display circuitry and perform one or more other functions, such as operating as touch sensing circuitry, or may be a single-function circuit element that can operate as display circuitry only. Therefore, in some examples, some of the circuit elements in the display pixel stackups can be multi-function circuit elements and other circuit elements may be single-function circuit elements. In other examples, all of the circuit elements of the display pixel stackups may be single-function circuit elements. 
     In addition, although examples herein may describe the display circuitry as operating during a display phase, and describe the touch sensing circuitry as operating during a touch sensing phase, it should be understood that a display phase and a touch sensing phase may be operated at the same time, e.g., partially or completely overlap, or the display phase and touch sensing phase may operate at different times. Also, although examples herein describe certain circuit elements as being multi-function and other circuit elements as being single-function, it should be understood that the circuit elements are not limited to the particular functionality in other examples. In other words, a circuit element that is described in one example herein as a single-function circuit element may be configured as a multi-function circuit element in other examples, and vice versa. 
     Multi-function circuit elements of display pixels of the touch screen can operate in both the display phase and the touch sensing phase. For example, during a touch sensing phase, common electrodes  401  can form touch signal lines, such as drive regions and sense regions. In some examples circuit elements can be grouped to form a continuous touch signal line of one type and a segmented touch signal line of another type. For example,  FIG. 4  shows one example in which drive line segments  403  and sense lines  405  correspond to drive line segments  301  and sense lines  223  of touch screen  220 . Other configurations are possible in other examples; for example, common electrodes  401  could be provided such that drive lines are each formed of a continuous drive region and sense lines are each formed of a plurality of sense region segments linked together through connections that bypass a drive region, as illustrated in the example of  FIG. 3B . 
     The drive regions in the examples of  FIGS. 3A and 4  are shown as rectangular regions including a plurality of display pixels, and the sense regions of  FIGS. 3A, 3B, and 4  are shown as rectangular regions including a plurality of display pixels extending the vertical length of the AMOLED display. In some examples, a touch pixel of the configuration of  FIG. 4  can include, for example, a 64×64 area of display pixels. However, the drive and sense regions are not limited to the shapes, orientations, and positions shown, but can include any suitable configurations according to examples of the disclosure. It is to be understood that the display pixels included in the touch pixels are not limited to those described above, but can be any suitable size or shape to permit touch capabilities according to examples of the disclosure. 
       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 an example integrated touch screen  550 . Stackups  500  can include a configuration of conductive lines that can be used to link drive region segments to form drive lines. 
     Stackups  500  can include elements in a first metal (M1) layer  501 , a second metal (M2) layer  503 , and a common electrode layer  505 . Each display pixel can include a portion of a common electrode  509 , such as common electrodes  401  in  FIG. 4 , that is formed in common electrode layer  505 . In some display pixels, breaks  513  can be included in the common electrodes  509  to separate different segments of common electrodes to form drive region segments  515  and a sense region  517 , such as drive line segments  403  and sense line  405 , respectively. Breaks  513  can include breaks in the x-direction that can separate drive region segments  515  from sense region  517 , and breaks in the y-direction that can separate one drive region segment  515  from another drive region segment. M1 layer  501  can include tunnel lines  519  that can electrically connect together drive region segments  515  through connections, such as conductive vias  521 , which can electrically connect tunnel line  519  to the common electrode in drive region segment display pixels. Tunnel line  519  can run through the display pixels in sense region  517  with no connections to the common electrode  509  in the sense region, i.e., no vias  521  in the sense region. The M1 layer can also include gate lines  520 . M2 layer  503  can include data lines  523 . Only one gate line  520  and one data line  523  are shown for the sake of clarity; however, a touch screen can include a gate line running through each horizontal row of display pixels and multiple data lines running through each vertical row of display pixels, for example, one data line for each red, green, blue (RGB) color sub-pixel in each pixel in a vertical row of an RGB AMOLED display integrated touch screen. Although M1 layer  501  is shown to be below M2 layer  503 , which is shown to be below common electrode layer  505 , it is understood that the ordering of these layers in the z-direction, as well as the ordering of the elements in each of these layers, can differ from what is shown in  FIG. 5 . For example, the elements in M1 layer  501  (e.g., tunnel line  519  and gate line  520 ) can be in M2 layer instead, or can be distributed amongst different metal layers. 
     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  550 . Structures such as data lines  523 , along with other pixel stackup elements such as transistors, pixel electrodes, common voltage lines, data lines, etc. (not shown), can operate as display circuitry of a display system to display an image on the touch screen  550  during a display phase. Structures such as common electrodes  509  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, gate lines  520  can be held to a fixed voltage while stimulation signals can be transmitted through a row of drive region segments  515  connected by tunnel lines  519  and conductive vias  521  to form electric fields between the stimulated drive region segments and sense region  517  to create touch pixels, such as touch pixel  226  in  FIG. 2 . In this way, the row of connected-together drive region segments  515  can operate as a drive line, such as drive line  222 , and sense region  517  can operate as a sense line, such as sense line  223 . When an object such as a finger approaches or touches a touch pixel, the object can affect the electric fields extending between the drive region segments  515  and the sense region  517 , 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  550 , 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 examples of the disclosure will be described with reference to  FIG. 6 .  FIG. 6  shows partial circuit diagrams of some of the touch sensing circuitry within display pixels in a drive region segment  601  and a sense region  603  of an example touch screen according to examples of the disclosure. For the sake of clarity, only one drive region segment is shown. Also 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. In addition, a touch sensing operation is described primarily in terms of a single display pixel  601   a  of drive region segment  601  and a single display pixel  603   a  of sense region  603 . However, it is understood that other display pixels in drive region segment  601  can include the same touch sensing circuitry as described below for display pixel  601   a , and the other display pixels in sense region  603  can include the same touch sensing circuitry as described below for display pixel  603   a . Thus, the description of the operation of display pixel  601   a  and display pixel  603   a  can be considered as a description of the operation of drive region segment  601  and sense region  603 , respectively. 
     Referring to  FIG. 6 , drive region segment  601  can include a plurality of display pixels including display pixel  601   a . Display pixel  601   a  can include a transistor such as thin film transistor (TFT)  607 , a data line  611 , a V DD  line  613 , an LED element such as OLED element  615 , and a portion  619  of common electrode  617 . Sense region  603  can include a plurality of display pixels including display pixel  603   a . Display pixel  603   a  can include a transistor such as TFT  609 , a data line  612 , an LED element such as OLED element  616 , and a portion  620  of common electrode  618 . TFT  609  can be connected to the same V DD  line  613  as TFT  607 . 
     During a touch sensing phase, OLED elements  615  and  616  can be maintained in an off state, the specifics of which will be described later. Drive signals can be applied to common electrode  617  through a tunnel line  621 . The drive signals can generate an electric field  623  between common electrode  617  of drive region segment  601  and common electrode  618  of sense region  603 , which can be connected to a sense amplifier, such as a charge amplifier  626 . Electrical charge can be injected into common electrode  618  of sense region  603 , 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 drive  601  and sense  603  regions. In this way, the measured voltage can provide an indication of touch on or near the touch screen. 
     The operation of part of the display circuitry of the AMOLED touch screen during a display phase according to examples of the disclosure will be described with reference to  FIGS. 7A-7C .  FIG. 7A  illustrates an exemplary AMOLED pixel circuit  750  that can be used in a regular top emission OLED display. The specifics of top emission and bottom emission OLEDs will be described later. The pixel circuit  750  can include an OLED element  701  having two terminals (a cathode  703  terminal and an anode  709  terminal), a p-type transistor such as TFT T 2   705 , and an n-type transistor such as TFT T 1   707 . The cathode  703  terminal of OLED element  701  can be electrically connected to cathode. Cathode  703  can be the signal line common to a plurality of pixel circuits in the touch screen, and can correspond to common electrode  401  or  509 , for example. The anode  709  terminal of OLED element  701  can be electrically connected to anode. OLED element  701  can be connected to cathode  703  and anode  709  in such a way as to allow current to flow through OLED element when the voltage at anode is higher than the voltage at cathode (i.e., OLED element is on, or “forward biased”). OLED element  701  can emit light when it is on. When the voltage at anode  709  is lower than the voltage at cathode  703 , substantially no current can flow through OLED element  701  (i.e., OLED element is off, or “reverse biased”). OLED element  701  can emit substantially no light when it is off. 
     Anode  709  can be electrically connected to the drain terminal of T 2   705 . The gate and source terminals of T 2   705  can be capacitively coupled by way of capacitor C st    711 , where one terminal of C st  can be electrically connected to the gate terminal of T 2  and the other terminal of C st  can be electrically connected to the source terminal of T 2 . The source terminal of T 2   705  can further be electrically connected to V DD    713 . The gate terminal of T 2   705  can further be electrically connected to the drain terminal of T 1   707 . The gate terminal of T 1  can be electrically connected to gate line  715 , and the source terminal of T 1  can be electrically connected to data line  717 . 
       FIG. 7B  illustrates another exemplary AMOLED pixel circuit  752  that can be used in a regular top emission OLED display. In  FIG. 7B , T 2   719  can be an n-type TFT instead of a p-type TFT as in  FIG. 7A . Therefore, the source terminal of T 2   719  can be electrically connected to anode  709 , and the drain terminal of T 2  can be electrically connected to V DD    713 . The gate and source terminals of T 2   719  can continue to be capacitively coupled by way of capacitor C st    711 . The remaining elements of pixel circuit  752  can be the same as that of pixel circuit  750  in  FIG. 7A . 
       FIG. 7C  illustrates an exemplary AMOLED pixel circuit  754  that can be used in an inverted OLED display. In the case of an inverted OLED display, the anode  709 , and not the cathode  703 , can be the common electrode, and the anode can be above the OLED element  701 . The configuration of T 2   719 , C st    711 , T 1   707 , and the other circuit elements can be the same as that in  FIG. 7B . However, the cathode  703  terminal of OLED element  701  can be electrically connected to the drain terminal of T 2   719 , and the anode  709  terminal of OLED element can be electrically connected to V DD    713 . 
     Referring to  FIG. 7A , during a display phase of the touch screen according to the examples of the disclosure, OLED element  701  can be forward biased (and can thus have current flowing through it), and can be emitting light. To allow for current to flow through OLED element  701 , the voltage at gate line  715  can be sufficiently high to turn on T 1   707  (i.e., the gate to source voltage of T 1  can be sufficiently high to turn on T 1 ). When T 1   707  is on, T 1  can act substantially as a short-circuit and can cause the voltage at data line  717  to be substantially mirrored at the gate terminal of T 2   705 . The voltage at data line  717 , and thus the voltage at the gate terminal of T 2   705 , can be sufficiently low to turn on T 2   705  (i.e., the gate to source voltage of T 2  can be sufficiently low to turn on T 2 ). When T 2   705  is on, T 2  can act substantially as a short-circuit and can cause the voltage at V DD    713  to be substantially mirrored at anode  709 . For OLED element  701  to be forward biased, the voltage at anode  709 , and thus the voltage at V DD    713 , can be higher than the voltage at cathode  703 . When this occurs, OLED element  701  can be forward biased, can have current flowing through it, and can be emitting light. Although this description has been provided with respect to the circuit of  FIG. 7A , it is understood that the operation of the circuits of  FIGS. 7B and 7C  is substantially similar to the operation of the circuit of  FIG. 7A . Further, for the sake of clarity, the examples below will be provided with respect to the structure of the circuit of  FIG. 7A ; however, it is understood that the examples may be adapted to be used with the circuits of  FIGS. 7B and 7C . For example, whereas the voltage at the gate terminal of a p-type TFT can be sufficiently low to turn on the p-type TFT, the opposite can be true for an n-type TFT; that is, the voltage at the gate terminal of an n-type TFT can be sufficiently high to turn on the n-type TFT. This modification can be extended to the circuits of  FIGS. 7B and 7C  to allow for proper operation. 
     To facilitate the operation of the AMOLED touch screen according to examples of the disclosure, portions of the display circuitry of the touch screen can be turned off during a touch sensing phase of the touch screen, and can be turned on during a display phase of the touch screen. Exemplary turn-off operations will be described with reference to  FIGS. 8 and 9A-9C . Although  FIGS. 8 and 9A-9C  are provided with display circuits that utilize a p-type TFT, as shown in  FIG. 7A , it is understood that the circuits of  FIGS. 7B and 7C  can be similarly utilized in the structures of  FIGS. 8 and 9A-9C . 
       FIGS. 8A and 8B  illustrate an exemplary AMOLED pixel circuit  850  configuration and operation for turning on and off an OLED element during touch sensing and display phases of the touch screen of the disclosure. The circuit configuration of  FIGS. 8A and 8B  is that of  FIG. 7A , and a partial circuit diagram of the circuit of  FIG. 7A  is provided in  FIG. 8B .  FIG. 8A  illustrates the voltage at V DD    801  during a transition from a pixel circuit ON phase to a pixel circuit OFF phase. During the pixel circuit ON phase, the voltage at V DD    801  can be V ON . V ON  can be sufficiently high, as described with reference to  FIG. 7A , such that OLED element  803  can be forward biased. All of the other voltages of the circuit can be set such that the circuit operates as described with reference to  FIG. 7A . 
     To transition to a touch sensing phase in which OLED element  803  can be off, the voltage at gate line  711  (not shown in  FIG. 8B ) of  FIG. 7A  can be sufficiently low to turn off T 1   707  (not shown in  FIG. 8B ). This can result in the voltage at the gate terminal of T 2   805  to be floating. Because the gate terminal of T 2   805  can be capacitively coupled to the source terminal of T 2  by way of C st    807 , the difference between the gate and source voltages of T 2  can remain substantially constant as long as the gate of T 2  is floating (i.e., C st  can substantially maintain the gate to source voltage of T 2 ). Therefore, T 2   805  can remain on irrespective of the voltage at V DD    801 . 
     Because T 2   805  can remain on irrespective of the voltage at V DD    801 , the voltage at V DD  can be lowered from V ON  to V OFF  while maintaining T 2  in an on state. Because T 2   805  can remain on, it can behave substantially like a short-circuit, and therefore the voltage at V DD    801  can be substantially mirrored at anode  809 . If V OFF  is less than the voltage at cathode  811 , OLED element  803  can be reverse biased, as described previously. As such, OLED element  803  can be off, and can emit substantially no light, thus turning off pixel circuit  850 . 
     During a touch sensing phase, when pixel circuit  850  is off, cathode  811  can be utilized as part of the touch sensing circuitry (i.e., as part of common electrode  617 ), as described with reference to  FIG. 6 . The voltage at V DD    801  during the touch sensing phase (V OFF ) can be sufficiently low such that through the range of voltages that can exist at cathode  811  during the touch sensing phase, OLED element  803  can remain reverse biased, and thus off. For example, if the voltage at cathode  811  during the touch sensing phase can vary from −5V to +5V, V OFF  can be less than −5V to ensure that OLED element  803  can remain reverse biased. To transition from an off state back to an on state, the steps described above can be reversed such that display phase operation can resume. 
       FIGS. 9A-9D  illustrate further exemplary AMOLED pixel circuit configurations and operations for turning on and off an OLED element during touch sensing and display phases of the touch screen of this disclosure. The AMOLED pixel circuit  950  of  FIG. 9B  is that of  FIG. 7A , except that an additional p-type TFT T EM1    915  can be electrically connected in series with T 2   905  and OLED element  903 , positioned between T 2  and OLED element. During a display phase of the touch screen, the voltage at the gate terminal of T EM1    915  (V G-EM    913 ) can be sufficiently low such that T EM1  can be on. When on, T EM1    915  can act substantially as a short-circuit and may not substantially affect the current flowing through OLED element  903 . The remaining elements of the pixel circuit  950  can operate as described with reference to  FIG. 7A . Turning OLED element  903  off (i.e., stopping current flow through OLED element) during a touch sensing phase of the touch screen can be accomplished by setting the voltage at V G-EM    913  to be sufficiently high such that T EM1    915  can be off. When off, T EM1    915  can act substantially as an open-circuit, thus substantially preventing current flow through OLED element  903 . This, in turn, can result in OLED element  903  turning off. In this way, the voltage at V DD    901  need not be regulated as described with reference to  FIG. 8  to turn off the pixel circuit  950 .  FIG. 9A  illustrates the voltage at V G-EM    913  during a display phase and a touch sensing phase of the touch screen. 
       FIGS. 9C and 9D  illustrate alternative configurations of the pixel circuit of  FIG. 9B , but can operate in substantially the same manner. In  FIG. 9C , T EM1    915  can be positioned between V DD    901  and T 2   905 , instead of between T 2  and OLED element  903 ; however, the pixel circuit  952  of  FIG. 9C  can otherwise operate in the same manner as the circuit of  FIG. 9B .  FIG. 9D  illustrates a pixel circuit  954  that has two p-type TFTs electrically connected in series with T 2   905 : T EM1    915  and T EM2    916 . T EM1    915  can be positioned between T 2   905  and OLED element  903 , and T EM2    916  can be positioned between T 2  and V DD    901 . During a touch sensing phase of the touch screen, T EM1    915  and T EM2    916  can be turned off in the manner described above with reference to  FIG. 9B . During a display phase of the touch screen, T EM1    915  and T EM2    916  can be turned on in the manner described above with reference to  FIG. 9B . 
     Although T EM1    915  and T EM2    916  have been described as being p-type transistors such as TFTs, it is understood that either or both can instead be n-type TFTs, in which case the voltages required to turn them on and off would be the reverse of what was described above. That is to say, if T EM1    915  were an n-type TFT, the voltage needed at V G-EM    913  to turn on T EM1  would be high, and the voltage needed at V G-EM  to turn off T EM1  would be low. The appropriate changes to the operation described above can be made to allow for the proper operation of the pixel circuits described. 
     The examples of this disclosure can be implemented in many types of LED displays, including both top emission OLED displays and bottom emission OLED displays. In bottom emission OLED displays, the transistors such as TFTs, metal routing, capacitors and OLED layers can share area on the substrate glass. Because the OLED layers can share space with the TFTs, the metal routing, and the capacitors, the remaining area for use by the OLED layers can be limited. This can result in small-area OLED layers, which can require high driving current densities to generate sufficient OLED light emission. In top emission OLED displays, the OLED layers can be formed on top of the TFT layers, which can provide the OLED layers with fewer area restrictions as compared with bottom emission OLED displays. Thus, lower driving current densities can be required to generate sufficient OLED light emission. 
       FIG. 10  illustrates an exemplary top emission OLED material stack  1050  according to examples of the disclosure. TFT layer  1001  can include various circuit elements of the pixel circuits of  FIG. 7, 8 or 9 , including T 2   905 , T EM1    915  or T EM2    916 . PLN  1003  can be a planarization layer for electrically isolating the circuit elements of TFT layer  1001  from the layers above, and for providing a substantially flat layer for facilitating the fabrication of the layers above it. Anode  1007  can provide an electrical connection between the circuit elements of TFT layer  1001  and OLED layer  1009 . Anode  1007  can correspond to anode  709 ,  809 , and/or  909 . OLED layer  1009  can correspond to OLED element  616 ,  701 ,  803  and/or  903 . PDL  1005  can be a layer for electrically isolating adjacent anodes  1007  and OLED layers  1009 . Finally, cathode  1011  can provide an electrical connection to OLED layers  1009 , and can correspond to cathode  703 ,  811  and/or  911 , for example. Anode  1007  and cathode  1011  can be formed of conductive materials; for example, cathode can be formed of many different types of transparent conductive materials, such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO). During a display phase of the touch screen, when current is flowing from TFT layer  1001 , through anode  1007  and OLED layer  1009 , to cathode  1011 , OLED layer can be on, and can emit light through cathode to display an image on the touch screen. 
     To facilitate the operation of the examples of this disclosure, it can be desired that the cathode  1011  of  FIG. 10  be patterned such that, during a touch sensing phase, cathode can operate as distinct drive and sense segments, and during a display phase, cathode can operate as a common electrode for the pixel circuits of the touch screen. Therefore, it can be necessary to electrically isolate portions of cathode  1011  to form segments such as drive line segment  301  and sense line  223  as shown in  FIG. 3A , while also providing for electrical connections, such as drive links  303 , between adjacent drive line segments to form drive lines  222 . However, OLED layer  1009  underneath cathode  1011  can be sensitive to processing steps taken subsequent to the forming of cathode, which can make it difficult to pattern cathode as described above.  FIGS. 11-17  illustrate various ways to provide the structure of the above-described cathode. 
     Unless otherwise noted, the opening of vias or the removal of material in the exemplary processes of the disclosure can be accomplished by a combination of photolithography and etching. Photolithography can be used to define the desired etch pattern on the surface of the material to be patterned, and the etching of the material in accordance with the desired etch pattern can remove the desired portions of the material. The etching of the material can be performed by utilizing any appropriate etch process, including but not limited to dry etching or wet etching. Further, unless otherwise noted, the deposition or formation of material can be accomplished by any appropriate deposition process, including but not limited to physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), molecular beam epitaxy (MBE), or atomic layer deposition (ALD). 
       FIGS. 11A and 11B  illustrate an exemplary process for patterning the cathode layer according to examples of the disclosure.  FIG. 11A  shows a top-view of a patterned cathode structure  1150  in accordance with examples of the disclosure. Drive line segments  1101  can be on either side of sense line  1103 , and can be electrically isolated from sense line by isolation slits  1110 . Both drive line segments  1101  and sense line  1103  can be formed of cathode  1011  of  FIG. 10 . OLED layers  1105  can be underneath drive line segments  1101  and sense line  1103 , and can correspond to OLED layers  1009  of  FIG. 10 . Drive line segments  1101  can be electrically connected to each other by way of anode connection  1107 . Anode connection  1107  can be formed of anode  1007  of  FIG. 10 , and can be positioned in between adjacent OLED layers  1105  so as to not overlap any OLED layers. Anode connection  1107  can be electrically connected to drive line segments  1101  by way of vias  1109 . The process steps for fabricating the patterned cathode structure  1150  of  FIG. 11A  will be described with reference to  FIG. 11B , which illustrates a cross-sectional view of cross-section X-Y at each process step. 
       FIG. 11B-1  illustrates the first step of the example process. Anode connection  1107  can be formed on PLN  1111 . Anode connection  1107  can be formed at the same time, and of the same material, as anode  1007  of  FIG. 10 , but can be electrically isolated from anode  1007  and can be in a different area of the touch screen (namely, not overlapping OLED layers  1105 ). Organic passivation  1113  can be formed on anode connection  1107 , and vias  1109  can be opened to allow for connection to anode connection  1107 . OLED layers  1105  can be formed in other areas of the touch screen (as shown in  FIG. 11A , not shown in  FIG. 11B ). Finally, cathode  1115  can be blanket deposited in vias  1109  and over organic passivation  1113 . 
       FIG. 11B-2  illustrates the next step of the example process. A thin film encapsulation layer TFE 1   1117  can be formed on cathode  1115 . Thin film encapsulation layers like TFE 1   1117 , with good barrier properties, can protect OLED layers  1105  that are below them from subsequent process steps, such as photolithography and etching. Here, TFE 1   1117  can protect OLED layers  1105  from the next steps in the process. 
       FIG. 11B-3  illustrates the next step of the example process. TFE 1   1117  can be etched to partially open isolation slits  1110 . OLED layers  1105  in other areas of the touch screen can be protected from the etching of TFE 1   1117  at isolation slits  1110  because of the coverage of TFE 1  in those areas. 
       FIG. 11B-4  illustrates the next step of the example process. Cathode  1115  can be etched to complete the opening of isolation slits  1110 . With the etching of cathode  1115  in this step, drive line segments  1101  and sense line  1103  can be defined, and drive line segments  1101  can be electrically isolated from sense line  1103  because of the removal of conductive cathode material between drive line segments and sense line. As described above, OLED layers  1105  in other areas of the touch screen can be protected from the etching of cathode  1115  at isolation slits  1110  because the coverage of TFE 1   1117  in those areas can protect OLED layers. 
       FIG. 11B-5  illustrates the final step of the example process. Thin film encapsulation layer TFE 2   1119  can be blanket deposited as a final protective layer over the material stack. As shown, drive line segments  1101  can be electrically connected to each other through vias  1109  and anode connection  1107 . Drive line segments  1101  can be electrically isolated from sense line  1103  by isolation slits  1110 . By way of the above-described process, the fabrication of the drive and sense line structure of  FIG. 3A , over OLED layers, can be accomplished. 
     Although the steps of the above process have been presented in a particular order, it is understood that the ordering of the process steps can be modified, where appropriate. Such modification can also be done for the processes presented in the remainder of the disclosure. 
       FIGS. 12A and 12B  illustrate another exemplary process for patterning the cathode layer according to examples of the disclosure.  FIG. 12A  shows the same top-view of a patterned cathode structure  1250  as shown in  FIG. 11A . The process steps of  FIG. 12B  can be the same as those of  FIG. 11B , except that in  FIG. 12B-4 , cathode  1215  can be oxidized, instead of etched, at isolation slits  1210 . Oxidization of an electrically conductive material such as cathode  1215  can reduce the conductivity of the material to substantially to that of an electrical insulator. Therefore, oxidization of cathode  1215  at isolation slits  1210  can electrically isolate adjacent portions of cathode, and can thus form drive line segments  1201  and sense line  1203 . In all other respects, the process of  FIG. 12  can be the same as the process of  FIG. 11 . 
       FIGS. 13A and 13B  illustrate another exemplary process for patterning the cathode layer according to examples of the disclosure. Instead of electrically connecting adjacent drive line segments  1301  by way of an electrical connection formed underneath the cathode  1315  of the touch screen, adjacent drive line segments can be electrically connected by way of an electrical connection formed over the cathode of the touch screen.  FIG. 13A  shows the same top-view of a patterned cathode structure  1350  as shown in  FIG. 11A .  FIG. 13B  shows the process steps that can be performed to form the patterned cathode structure  1350  of  FIG. 13A  at cross-section X-Y. 
       FIG. 13B-1  illustrates the first step of the example process. Organic passivation  1313  can be formed on PLN  1311 . OLED layers  1305  can be formed in other areas of the touch screen (as shown in  FIG. 13A , not shown in  FIG. 13B ). Finally, cathode  1315  can be blanket deposited to cover organic passivation  1313 . 
       FIG. 13B-2  illustrates the next step of the example process. Thin film encapsulation layer TFE 1   1317  can be deposited over cathode  1315 . TFE 1   1317  can protect OLED layers  1305  from the next steps in the process. 
       FIG. 13B-3  illustrates the next step of the example process. TFE 1   1317  can be etched to partially open isolation slits  1310 . OLED layers  1305  in other areas of the touch screen can be protected from the etching of TFE 1   1317  because the coverage of TFE 1  in those areas can protect OLED layers. 
       FIG. 13B-4  illustrates the next step of the example process. Cathode  1315  can be etched to complete the opening of isolation slits  1310 . With the etching of cathode  1315  in this step, drive line segments  1301  and sense line  1303  can be defined, and drive line segments can be electrically isolated from the sense line because of the removal of conductive cathode material between drive line segments and the sense line. As described above, OLED layers  1305  in other areas of the touch screen can be protected from the etching of cathode  1315  because the coverage of TFE 1   1317  in those areas can protect OLED layers. 
       FIG. 13B-5  illustrates the next step of the example process. Thin film encapsulation layer TFE 2   1319  can be deposited, and vias  1309  can be etched in TFE 1   1317  and TFE 2  to allow for electrical connection to cathode  1315 . 
       FIG. 13B-6  illustrates the last step of the example process. Drive line connection  1307  can be formed inside vias  1309  and across TFE 2   1319 . Drive line connection  1307  can be formed of ITO or IZO, for example. Finally, thin film layer TFE 3   1323  can be deposited over the material stack. As shown, drive line segments  1301  can be electrically connected to each other through vias  1309  and drive line connection  1307 . Drive line segments  1301  can be electrically isolated from sense line  1303  by isolation slits  1310 . By way of the above-described process, the fabrication of the drive and sense line structure of  FIG. 3A , over OLED layers, can be accomplished. 
     Because the cathode layer (or the anode layer in the case of inverted OLED displays) of the touch screen of this disclosure can be formed over LED layers such as OLED layers, it can be preferable for the cathode layer (or the anode layer) to be transparent. Thus, it can be necessary to make the cathode layer thin. This, in turn, can cause the sheet resistance of the cathode layer to be high. High resistance coupled with the various capacitances inherent in the OLED material stack can result in increased voltage delay in drive lines, for example. Therefore, reducing the sheet resistance of the cathode layer can be desired.  FIGS. 14A and 14B  illustrate an exemplary way of lowering the sheet resistance of the cathode layer according to examples of the disclosure.  FIGS. 14A and 14B  show a top-view of the drive and sense line structure of  FIG. 3A  over OLED layers  1405 . Drive line connections  1407  can correspond to anode connections  1107  or  1207 , or drive line connection  1307 . Extra lines  1421  can be formed as a mesh-like structure across drive line segments  1401  and sense line  1403 , and can be formed in between OLED layers  1405  so as not to obstruct the light emitted from OLED layers. Extra lines  1421  can be electrically connected to the cathode layer by way of vias  1409 . Because extra lines  1421  can be formed between OLED layers  1405 , extra lines need not be as transparent as the cathode layer that can form drive line segments  1401  and sense line  1403 . Therefore, extra lines  1421  can be thicker than the cathode layer, or can be formed of a different, lower resistance, material than the cathode layer, or both. The effective sheet resistance of the cathode layer can therefore be reduced without affecting the transparency of the cathode layer (i.e., drive line segments  1401  and sense line  1403 ). 
     Using the processes of  FIG. 11, 12 , or  13 , extra lines  1421  can be formed of the same material and at the same time as anode connections  1107  or  1207 , or drive line connection  1307 .  FIG. 14A  shows an example with a single drive line connection  1407  between adjacent drive line segments  1401 .  FIG. 14B  shows an example with two drive line connections  1407  between adjacent drive line segments  1401 . More drive line connections  1407  can be used in accordance with the examples of the disclosure. 
     Sometimes, it can be preferable or necessary to connect adjacent drive line segments by way of drive line connections that overlap the LED layers of the touch screen. This can be the case, for example, in high density AMOLED displays where there is minimal space between adjacent OLED layers.  FIGS. 15A and 15B  illustrate an exemplary process for forming a drive line connection over OLED layers according to examples of the disclosure.  FIG. 15A  shows a top-view of a patterned cathode structure  1550  in accordance with the examples of this disclosure. Drive line segments  1501  can be on either side of sense line  1503 , and can be electrically isolated from sense line by isolation slits  1510 . Both drive line segments  1501  and sense line  1503  can be formed of cathode  1011  of  FIG. 10 . OLED layers  1505  can be underneath drive line segments  1501  and sense line  1503 , and can correspond to OLED layers  1009  of  FIG. 10 . Drive line segments  1501  can be electrically connected to each other by way of drive line connection  1507 . Drive line connection  1507  can partially overlap OLED layers  1505 , and it can therefore be preferable for drive line connection  1507  to be substantially transparent. Drive line connection  1507  can be formed of ITO or IZO, for example. Drive line connection  1507  can be electrically connected to drive line segments  1501  by way of vias  1509 . The process steps for fabricating the patterned cathode structure  1550  of  FIG. 15A  will be described with reference to  FIG. 15B , which illustrates a cross-sectional view of cross-section X-Y at each process step. 
       FIG. 15B-1  illustrates the first step of the example process. Anodes  1506  can be formed on PLN  1511 . Anodes  1506  can correspond to anodes  1007  in  FIG. 10 . OLED layers  1505  can be formed on anodes  1506 . OLED layers can correspond to OLED layers  1009  in  FIG. 10 . Anode  1506  and OLED layer  1505  stacks can be electrically isolated from each other by organic passivation  1513 . Organic passivation can correspond to PDL  1005  in  FIG. 10 . Cathode  1515  can be blanket deposited over the material stack, and can correspond to cathode  1011  in  FIG. 10 . 
       FIG. 15B-2  illustrates the next step of the example process. A thin film encapsulation layer TFE 1   1517  can be formed on cathode  1515 . TFE 1   1517  can protect OLED layers  1505  from the next steps in the process. 
       FIG. 15B-3  illustrates the next step of the example process. TFE 1   1517  can be etched to partially open isolation slits  1510 . OLED layers  1505  can be protected from the etching of TFE 1   1517  at isolation slits  1510  because the coverage of TFE 1  over OLED layers can protect OLED layers. 
       FIG. 15B-4  illustrates the next step of the example process. Cathode  1515  can be etched to complete the opening of isolation slits  1510 . With the etching of cathode  1515  in this step, drive line segments  1501  and sense line  1503  can be defined. Drive line segments  1501  can be electrically isolated from sense line  1503  by organic passivation  1513  and because of the removal of conductive cathode  1515  material between drive line segments and sense line. As described above, OLED layers  1505  can be protected from the etching of cathode  1515  because the coverage of TFE 1   1517  over OLED layers can protect OLED layers. 
       FIG. 15B-5  illustrates the next step of the example process. Thin film encapsulation layer TFE 2   1519  can be deposited, and vias  1509  can be etched in TFE 1   1517  and TFE 2  to allow for electrical connection to cathode  1515 . 
       FIG. 15B-6  illustrates the last step of the example process. Drive line connection  1507  can be formed inside vias  1509  and across TFE 2   1519 . As shown, drive line segments  1501  can be electrically connected to each other through vias  1509  and drive line connection  1507 . Drive line segments  1501  can be electrically isolated from sense line  1503  by isolation slits  1510  and organic passivation  1513 . By way of the above-described process, the fabrication of the drive and sense line structure of  FIG. 3A , over OLED layers, can be accomplished. 
     Instead of blanket depositing the cathode layer, and then subsequently etching it to provide isolation for the drive and sense segments of the examples of this disclosure, the cathode layer can be deposited by way of a shadow mask.  FIGS. 16A and 16B  illustrate an exemplary process for performing shadow mask deposition of the cathode layer according to examples of this disclosure.  FIG. 16A  shows a top-view of the process of depositing a cathode layer, corresponding to drive line segments  1601  and sense lines  1603 , by using a shadow mask. A shadow mask allows for selective deposition of a material on a surface by way of a physical mask placed between the source of the material being deposited and the surface onto which the material is being deposited. Areas in the mask with holes or openings allow for the material to pass through and deposit on the surface. Areas in the mask without holes or openings prevent the material from passing through, and therefore no material is deposited at the corresponding area on the surface.  FIG. 16A  shows the deposition of drive line segments  1601  and sense lines  1603  using three shadow masks. More or fewer shadow masks can be used in accordance with this example. Further, it is understood that while the drive and sense line structure of  FIG. 3A  is illustrated, the drive and sense line structure of  FIG. 3B  can be similarly formed. 
       FIG. 16A-1  illustrates the first step of the example process. Alternate rows of drive line segments  1601  can be deposited by way of a shadow mask having openings corresponding to the positioning of drive line segments on the surface of the touch screen.  FIG. 16A-2  illustrates the next step of the example process. Sense lines  1603  can be deposited by way of a shadow mask as described above.  FIG. 16A-3  illustrates the last step of the example process. The remaining alternate rows of drive line segments  1601  can be deposited by way of a shadow mask as described above. Finally, a thin film encapsulation layer can be blanket deposited (not shown in  FIG. 16A ) over drive line segments  1601  and sense line  1603  to encapsulate the material stack. As described throughout this disclosure, it can be necessary to electrically connected adjacent drive line segments  1601  by way of drive line connections  1607  to form drive lines, such as drive lines  222  of  FIG. 3A . In this example, drive line connections  1607  can be formed prior to shadow mask deposition of drive line segments  1601  and sense line  1603 .  FIG. 16B  illustrates a cross-sectional view of cross-section X-Y during the process steps of  FIG. 16A  to better show drive line connections  1607 . 
       FIG. 16B-1  illustrates the first step of the example process. Drive line connection  1607  can be formed on PLN  1611 . Drive line connection  1607  can correspond to anode connections  1107  or  1207 , for example. Organic passivation  1613  can be formed on drive line connection  1607  and PLN  1611 , and can be etched at vias  1609  to allow for electrical connection to drive line connection. OLED layers  1605  (not shown in  FIG. 16B ) can be formed in other areas of the touch screen. Drive line segment  1601  portion of cathode  1615  can be deposited by shadow mask. It is noted that no need exists to further etch cathode  1615  to form drive line segment  1601  portion of cathode because shadow mask deposition can allow for pre-patterned deposition of cathode. 
       FIG. 16B-2  illustrates the next step of the example process. Sense line  1603  portion of cathode  1615  can be deposited by shadow mask. Sense line  1603  and drive line segments  1601  can be electrically isolated from each other because no electrical connection can exist between them, whether in cathode  1615  or by drive line connection  1607 . It is noted that no need exists to further etch cathode  1615  to form sense line segment  1603  portion of cathode for the reasons described above. 
       FIG. 16B-3  illustrates the last step of the example process. A thin film encapsulation layer TFE 1   1617  can be formed on drive line segment  1601  and sense line  1603  portions of cathode  1615 . By way of the above-described process, the fabrication of the drive and sense line structure of  FIG. 3A , over OLED layers, can be accomplished. Further, the shadow mask deposition process of  FIG. 16  allows for no photolithography or etching process steps after the formation of OLED layers  1605 , which can help to prevent damage to OLED layers on the touch screen. 
     Alternatively to shadow mask deposition, laser ablation can be performed to form the drive and sense segments of the examples of this disclosure.  FIGS. 17A and 17B  illustrate an exemplary process for performing laser ablation to form drive and sense segments according to examples of the disclosure.  FIG. 17A  shows a top-view of a process for defining drive line segments  1701  and sense lines  1703  on the surface of the touch screen.  FIG. 17A-1  illustrates the first step of the example process. Cathode  1715  can be blanket deposited over the surface of the touch screen.  FIG. 17A-2  illustrates the second step of the process. Cathode  1715  can be laser patterned to scribe out portions of cathode  1715  to form drive line segments  1701  and sense lines  1703  such that substantially no cathode material exists between drive line segments and sense lines. Finally, a thin film encapsulation layer can be blanket deposited (not shown in  FIG. 17A ) over drive line segments  1701  and sense lines  1703  to encapsulate the material stack. As described throughout this disclosure, it can be necessary to electrically connect adjacent drive line segments  1701  by way of drive line connections  1707  to form drive lines, such as drive lines  222  of  FIG. 3A . In this example, drive line connections  1707  can be formed prior to the deposition, and the laser ablation, of cathode  1715  to form drive line segments  1701  and sense lines  1703 .  FIG. 17B  illustrates a cross-sectional view of cross-section X-Y during the process steps of  FIG. 17A  to better show drive line connections  1707 . 
       FIG. 17B-1  illustrates the first step of the example process. Drive line connection  1707  can be formed on PLN  1711 . Drive line connection  1707  can correspond to anode connections  1107  or  1207 , for example. Organic passivation  1713  can be formed on drive line connection  1707  and PLN  1711 , and can be etched at vias  1709  to allow for electrical connection to drive line connection. OLED layers  1705  (not shown in  FIG. 17B ) can be formed in other areas of the touch screen. Cathode  1715  can be blanket deposited over the material stack. 
       FIG. 17B-2  illustrates the next step of the example process. Cathode  1715  can be laser patterned to form drive line segment  1701  and sense line  1703  portions of cathode. Drive line segments  1701  and sense line  1703  can be electrically isolated from each other because no electrical connection can exist between them, whether in cathode  1715  or by drive line connection  1707 . Further, the laser energy used during the laser patterning can be regulated to avoid damage to the material stack below cathode  1715 , including organic passivation  1713 . 
       FIG. 17B-3  illustrates the last step of the example process. A thin film encapsulation layer TFE 1   1717  can be formed on drive line segment  1701  and sense line  1703  portions of cathode  1715 . By way of the above-described process, the fabrication of the drive and sense line structure of  FIG. 3A , over OLED layers, can be accomplished. 
     Because the drive line segments and sense lines of the examples of the disclosure can operate as a cathode for a pixel circuit during a display phase of the touch screen, it can be beneficial to ensure that the drive line segments and the sense lines properly cover the LED emission layers, such as OLED emission layers, in the touch screen. Therefore, in any of the fabrication procedures described above, it can be preferable to modify the distance between adjacent OLED emission layers to ensure proper cathode layer coverage of the OLED emission layers.  FIGS. 18A-18D  illustrate an exemplary process for modifying the distance between adjacent OLED emission layers according to examples of the disclosure. 
       FIGS. 18A and 18B  illustrate why OLED emission layer distance modification can be necessary.  FIG. 18A  shows a top-view of a portion of a touch screen according to examples of the disclosure. Drive line segment  1801  can be adjacent to sense line  1803 . OLED layers  1805  can be covered by drive line segment  1801  and sense line  1803 , which can act as a cathode for OLED layers during a display phase of the touch screen. 
       FIG. 18B  shows a zoomed-in view of the area between drive line segment  1801  and sense line  1803 . Drive line segment  1801  can be formed over OLED layer  1805 , which can be formed over anode  1807 . Sense line  1803  can be formed over OLED layer  1805 , which can be formed over anode  1807 . OLED distance  1825  can be the distance between adjacent OLED layers  1805 . Isolation width  1827  can be the distance between adjacent portions of cathode  1815 , i.e., the distance between drive line segment  1801  and sense line  1803 . Minimum anode overlap  1829  can be the minimum distance that the edge of anode  1807  needs to extend over the edge of OLED layer  1805  for desired OLED operation. Minimum cathode overlap  1831  can be the minimum distance that the edge of cathode  1815  needs to extend over the edge of OLED layer  1805  for desired OLED operation. If the fabrication steps of forming drive line segment  1801  and sense line  1803  provide no additional constraints to those provided above, then isolation width  1827  can be reduced to almost zero, and OLED distance  1825  can be slightly larger than twice minimum cathode overlap  1831 . OLED distance  1825  cannot be reduced to exactly twice minimum cathode overlap  1831  because it is desired that drive line segment  1801  and sense line  1803  be electrically isolated from each other for proper touch screen operation; reducing OLED distance to twice minimum cathode overlap would mean that isolation width would be zero, which would mean that drive line segment  1801  and sense line  1803  would be touching, and thus not electrically isolated from each other. 
     Sometimes the process for fabricating drive line segment  1801  and sense line  1803  can provide a constraint as to how close drive line segment and sense line can be formed. That is to say, the fabrication process utilized might provide for a minimum distance between drive line segment  1801  and sense line  1803  that is greater than the minimum distance described above. For example, photolithography and etching can have a minimum resolution limit, or shadow mask deposition can have a minimum mask aperture limit. In cases such as these, it can desirable to adjust the spacing of adjacent OLED layers  1805  only at the edges of drive line segment  1801  and sense line  1803  so that the spacing of OLED layers in other areas of the touch screen, and thus the general OLED aperture (i.e., the spacing between OLED pixels), can be left unchanged. 
       FIG. 18C  illustrates one way to reduce the spacing of OLED layers at the edges of touch segments (i.e., drive line segments and sense lines). The touch screen  1800  can include a plurality of OLED pixel banks  1802 . Each pixel bank can include a plurality of OLED layers  1805 ; in this example, it could be three: one OLED layer each for red light, green light, and blue light. The touch screen can also include a plurality of touch segments  1801  overlaying the pixel banks  1802 . The touch segments  1801  can correspond to drive line segments  301  and sense lines  223  of  FIG. 3A , for example. Touch segments  1801  can be separated from each other by isolation width  1827 . To accommodate the minimum necessary isolation width  1827 , as described above, the dimensions of OLED layers  1805  adjacent to touch segment  1801  boundaries can be modified. For example, the right-most OLED layer  1805  in a pixel bank  1802  B can have its size reduced in the x-direction to accommodate the minimum required isolation width  1827 , as shown. The dimensions of all of the OLED layers  1805  in a pixel bank  1802  C can be reduced in the y-direction for the same reason as above. Such modifications can be made to the remaining pixel banks  1802  as needed. However, pixel bank  1802  A need not be modified because pixel bank A, as defined, is not adjacent to a touch segment  1801  boundary. By proceeding with the modifications of the pixel banks  1802  as described above, the general spacing between, and the size of, most OLED layers  1805  on the touch screen  1800  can remain unchanged while allowing for the accommodation of a minimum isolation width  1827  as dictated by process parameters. The process steps for modifying the effective dimensions of certain OLED layers will be described with reference to the cross-sectional view of cross-section X-Y of  FIG. 18C . 
       FIG. 18D  illustrates a process to reduce the dimensions of touch segment boundary OLED layers without the need to modify the shadow mask used to deposit the OLED layers.  FIG. 18D-1  illustrates the first step of the example process. Anodes  1806  can be formed on PLN  1811 . Anodes  1806  can correspond to anodes  1007  in  FIG. 10 , for example. Organic passivation  1813  can be formed between anodes  1806 , and can correspond to PDL  1005  in  FIG. 10 , for example. OLED layers  1805  can be deposited by shadow mask (the concept of shadow mask deposition was described previously). Anode  1806  and OLED layer  1805  stacks can be electrically isolated from each other by organic passivation  1813 . 
     Reduced OLED layer  1807  can be at the boundary of touch segment  1801 , and can be deposited with the same shadow mask as OLED layers  1805 . However, during the formation of organic passivation  1813 , enlarged organic passivation  1814  at the boundary of touch segment  1801  can be formed to extend towards reduced OLED layer  1807 . Therefore, during shadow mask deposition of OLED layers  1805 , reduced OLED layer  1807  can be partially formed on anode  1806  and enlarged organic passivation  1814 . The portion of reduced OLED layer  1807  that is formed on enlarged organic passivation  1814  can correspond to the desired reduction, in the x-direction, of reduced OLED layer. 
       FIG. 18D-2  illustrates the next step of the example process. Touch segments  1801  can be deposited by shadow mask, and can be isolated from each other by isolation width  1827 . 
       FIG. 18D-3  illustrates the last step of the example process. Thin film encapsulation layer TFE  1817  can be deposited over the material stack. The portion of reduced OLED layer  1807  that is not in contact with anode  1806  may not contribute to the light emitted from reduced OLED layer because it is not in contact with anode. Therefore, touch segment  1801  need not overlap the entirety of reduced OLED layer  1807 , but only the portion of reduced OLED layer that is in contact with anode  1806 . Accordingly, the effective dimension of reduced OLED layer  1807  can be smaller than that of OLED layers  1805 . In the way described above, the dimensions of touch segment boundary OLED layers can be reduced without the need to modify the shadow mask used to deposit the OLED layers. 
     Although the above process has been described only with reference to modifying the dimensions of LED layers, such as OLED layers, at the boundaries of touch segments, the dimensions of OLED layers adjacent to drive line connections can similarly be modified. For example, more area can be provided for drive line connection  1807  by modifying the dimensions of OLED layers  1805  that are adjacent to drive line connection in the manner described with reference to  FIGS. 18C and 18D . 
     Although examples of this disclosure have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of examples of this disclosure as defined by the appended claims. 
     Therefore, according to the above, some examples of the disclosure are directed to a touch screen comprising a transistor layer, a first layer disposed over the transistor layer and configured to operate as a light-emitting diode (LED) cathode during a display phase and as touch circuitry during a touch sensing phase, and an LED layer disposed between the transistor layer and the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the LED layer comprises an organic light-emitting diode (OLED) layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the transistor layer comprises a first transistor connected to the LED layer, and a power supply line connected to the first transistor. Additionally or alternatively to one or more of the examples disclosed above, in some examples, during the display phase, the power supply line voltage is set to a first voltage, and during the touch sensing phase, the power supply line voltage is set to a second voltage. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first voltage causes the LED layer to emit light, and the second voltage causes the LED layer to not emit light. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the touch screen further comprises a second transistor connected to the first transistor, and a gate voltage line connected to a gate terminal of the second transistor, wherein during the display phase, the gate voltage line is set to a first voltage, and during the touch sensing phase, the gate voltage line is set to a second voltage. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first voltage causes the second transistor to turn on, and the second voltage causes the second transistor to turn off. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first layer comprises a plurality of drive lines and a plurality of sense lines. Additionally or alternatively to one or more of the examples disclosed above, in some examples, a drive line comprises a first drive line segment, and a second drive line segment electrically connected to the first drive line segment by a drive line connection. 
     Some examples of the disclosure are directed to a method for operating a touch screen comprising operating, during a display phase, a first layer as a cathode of a light-emitting diode (LED) layer, and operating, during a touch sensing phase, the first layer as touch circuitry. Additionally or alternatively to one or more of the examples disclosed above, in some examples, operating the first layer as the cathode of the LED layer comprises operating the first layer as the cathode of an organic light-emitting diode (OLED) layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, operating the first layer as the cathode of the LED layer comprises setting the voltage of a power supply line connected to a transistor to a first voltage that causes the LED layer to emit light, and operating the first layer as touch circuitry comprises setting the voltage of the power supply line to a second voltage that causes the LED layer to not emit light. Additionally or alternatively to one or more of the examples disclosed above, in some examples, operating the first layer as touch circuitry comprises operating the first layer as a plurality of drive line segments and a plurality of sense lines, and electrically connecting a first drive line segment to a second drive line segment. 
     Some examples of the disclosure are directed to a method for fabricating a light-emitting diode (LED) touch screen, the method comprising forming a plurality of LED layers, and forming, over the LED layers, a plurality of regions of a first layer configurable to operate as a plurality of LED cathodes during a display phase and as touch circuitry during a touch sensing phase. Additionally or alternatively to one or more of the examples disclosed above, in some examples, forming the plurality of LED layers comprises forming a plurality of organic light-emitting diode (OLED) layers. Additionally or alternatively to one or more of the examples disclosed above, in some examples, forming the plurality of regions of the first layer comprises depositing the first layer over the LED layers, and removing portions of the first layer to form regions of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, forming the plurality of regions of the first layer comprises depositing the first layer over the LED layers, and oxidizing portions of the first layer to form regions of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method further comprises depositing a second layer over the first layer, and removing portions of the second layer to form regions of the second layer, wherein the second layer protects the LED layer from the removal of portions of the first layer and the second layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing portions of the first layer and the second layer comprises etching portions of the first layer and the second layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing portions of the first layer comprises laser ablating portions of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, forming the plurality of regions of the first layer comprises depositing the first layer using a shadow mask. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method further comprises modifying the dimensions of an LED layer at a boundary of one of the plurality of regions of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, forming the plurality of regions of the first layer comprises forming, of the first layer, a plurality of drive line segments and a plurality of sense lines, and electrically connecting a first drive line segment to a second drive line segment using a drive line connection. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method further comprises forming the drive line connection over the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method further comprises forming the drive line connection under the first layer.

Metadata:
Filing Date: 20130213
Publication Date: 20160510
Grant Date: 20160510
Priority Date: 20130213
Inventors: GUPTA VASUDHA
CHANG SHIH CHANG
PARK YOUNG-BAE
CHANG TING-KUO
Assignee: APPLE INC
CPC Classifications: [{"code": "G09G2300/0866", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3233", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/34", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2300/0861", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/323", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04184", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2300/0861", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/3233", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/3208", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2300/0866", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2300/0866", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2300/0861", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3233", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 50029270