PATENT DOCUMENT

Publication Number: US-8711570-B2
Application Number: US-201113165748-A
Country: US
Kind Code: B2

Title: Flexible circuit routing

Abstract:
Flexible circuits for routing signals of a device, such as a touch sensor panel of a touch sensitive device, are provided. The flexible circuit can include a first set of traces for routing a first set of lines and a second set of traces for routing a second set of lines. The first set of traces can couple together the ends of at least a portion of the first set of lines. Additionally, the first set of traces can be non-intersecting or non-overlapping with the second set of traces. The flexible circuit can have a T-shape configuration and can be incorporated within a touch sensitive device, display device, printed circuit board, or the like. The flexible circuit can be placed over another flexible circuit, and can extend onto the device.

Claims:
What is claimed is: 
     
       1. A flex circuit comprising:
 a first line contact portion operable to couple to a first end of a first set of lines; 
 a second line contact portion operable to couple to a second end of the first set of lines; 
 a third line contact portion operable to couple to a second set of lines; 
 a first output portion; 
 a first set of traces coupling together the first line contact portion, the second line contact portion, and the output portion; and 
 a second set of traces coupling together the third line contact portion and the output portion, wherein the first set of traces and second set of traces are non-overlapping with each other. 
 
     
     
       2. The flex circuit of  claim 1 , wherein the first set of lines comprises a set of drive lines of a touch sensitive display, and wherein the second set of lines comprises a set of sense lines of the touch sensitive display. 
     
     
       3. The flex circuit of  claim 1 , wherein the first set of traces is operable to couple the first end of at least a portion of the first set of lines to the second end of each corresponding line. 
     
     
       4. The flex circuit of  claim 1 , wherein the first set of traces create an open circuit between the first end of at least one line of the first set of lines and the second end of the at least one line. 
     
     
       5. The flex circuit of  claim 1 , wherein the flex circuit comprises a first layer and a second layer. 
     
     
       6. The flex circuit of  claim 5 , wherein the second set of traces is routed through the first layer, and wherein the first set of traces is routed through the first layer and the second layer. 
     
     
       7. The flex circuit of  claim 1  incorporated into at least one of a mobile telephone, a digital media player, an LCD, an OLED display, or a personal computer. 
     
     
       8. A device including the flex circuit of  claim 1 , wherein the flex circuit is a second flex circuit attached to a distal end of a substrate, the device further comprising:
 a first flex circuit attached to the distal end of the substrate, 
 wherein the second flex circuit overlaps the first flex circuit. 
 
     
     
       9. The device of  claim 8 , wherein the first flex circuit is coupled to an integrated circuit at the distal end of the substrate. 
     
     
       10. The device of  claim 8 , further comprising a grounded silver film disposed between the first flex circuit and the second flex circuit. 
     
     
       11. The device of  claim 8 , wherein the second flex circuit comprises at least one pre-bend section operable to reduce a distance between the second flex circuit and the first flex circuit. 
     
     
       12. The device of  claim 8 , further comprising a stiffener disposed on the second flex circuit, the stiffener operable to limit a distance between the second flex circuit and the first flex circuit, wherein the stiffener comprises a grounded metal plate or polyimide film. 
     
     
       13. The device of  claim 8 , wherein the second flex circuit is in a T-shape configuration.

Description:
FIELD 
     This relates generally to flexible printed circuits (FPCs), and, more specifically, to routing signals using an FPC. 
     BACKGROUND 
     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 sensitive devices, such as touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation. A touch sensitive device can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device, such as a liquid crystal display (LCD), that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. The touch sensitive device 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, the touch sensitive device can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event. 
     Some touch sensitive devices that incorporate touch sensor panels can include FPCs for routing signals indicative of a touch event to and from the touch sensor panel. Other devices, such as LCDs, organic light-emitting diode (OLED) displays, printed circuit boards, and the like, can also include FPCs for routing signals. While relatively small, the FPCs can still add to the size of the device and block critical areas that could otherwise be used for other device components, such as receivers, cameras, and the like. Thus, compact FPCs are desired. 
     SUMMARY 
     This relates to flexible circuits for routing signals within a device, for example, routing signals of a touch sensor panel of a touch sensitive device. The flexible circuit can include a first set of traces for routing a first set of lines (e.g., drive lines of the touch sensor panel to stimulate the panel) and a second set of traces for routing a second set of lines (e.g., sense lines of the touch sensor panel to sense a touch event). In some embodiments, the first set of traces can couple together the ends of at least a portion of the first set of lines (e.g., drive lines). Additionally, the first set of traces can be non-intersecting or non-overlapping with the second set of traces. In some embodiments, the flexible circuit can include two layers on which the first and second set of traces can be located. In some embodiments, the flexible circuit can have a T-shape configuration and can be incorporated within a touch sensitive device, display device, printed circuit board (PCB), or the like. The flexible circuit can be placed over another flexible circuit, and can extend onto the device, for example, onto a thin film transistor glass of a touch sensitive device. The flexible circuit can advantageously reduce the capacitive coupling between the first set of lines (e.g., drive lines) and the second set of lines (e.g., sense lines), reduce the impedance of the first set of lines (e.g., drive lines), and limit the size of the flexible circuit. 
     Processes for routing signals of a device, such as a touch sensitive device, display device, PCB, or the like, are also disclosed, including routing first and second sets of traces on a flexible circuit so that the traces are non-overlapping. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary touch sensor panel according to various embodiments. 
         FIG. 2  illustrates a top view of an exemplary T-shaped FPC according to various embodiments. 
         FIG. 3  illustrates a top view of an exemplary touch sensitive device having a T-shaped FPC according to various embodiments. 
         FIG. 4  illustrates a cross-sectional view of an exemplary touch sensitive device having a T-shaped FPC according to various embodiments. 
         FIG. 5  illustrates a top view of an exemplary T-shaped FPC according to various embodiments. 
         FIG. 6  illustrates a top view of another exemplary T-shaped FPC according to various embodiments. 
         FIG. 7  illustrates a cross-sectional view of an exemplary touch sensitive device having a T-shaped FPC according to various embodiments. 
         FIG. 8  illustrates an exemplary process for routing drive lines and sense lines of a touch sensor panel according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of example embodiments, reference is made to the accompanying drawings in which it is shown by way of illustration specific embodiments that can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the various embodiments. 
     This relates to flexible circuits for routing signals within a device, for example, routing signals of a touch sensor panel of a touch sensitive device. The flexible circuit can include a first set of traces for routing a first set of lines (e.g., drive lines of the touch sensor panel to stimulate the panel) and a second set of traces for routing a second set of lines (e.g., sense lines of the touch sensor panel to sense a touch event). The first set of traces can couple together the ends of at least a portion of the first set of lines (e.g., drive lines). Additionally, the first set of traces can be non-intersecting or non-overlapping with the second set of traces. In some embodiments, the flexible circuit can include two layers on which the first and second set of traces can be located. In some embodiments, the flexible circuit can have a T-shape configuration and can be incorporated within a touch sensitive device, display device, PCB, or the like. The flexible circuit can be included within a device, such as a touch sensitive device, display device, PCB, or the like, and placed over another flexible circuit. These will be described in more detail below. The flexible circuit can advantageously reduce the capacitive coupling between the first set of lines (e.g., drive lines) and the second set of lines (e.g., sense lines), reduce the impedance of the first set of lines (e.g., drive lines), and limit the size of the flexible circuit. Processes for routing signals of a device, such as a touch sensitive device, display device, PCB, or the like, are also disclosed. 
     While the flexible circuits are described herein as being used with a touch sensitive device, it should be appreciated that the flexible circuits can similarly be used with other devices, such as display devices, PCBs, and the like. 
       FIG. 1  illustrates a portion of an exemplary touch sensor panel  100  according to various embodiments. Touch sensor panel  100  can include an array of pixels  105  that can be formed at the crossing points between rows of drive lines  101  (D0-D3) and columns of sense lines  103  (S0-S4). Each pixel  105  can have an associated mutual capacitance Csig  111  formed between the crossing drive lines  101  and sense lines  103  when the drive lines are stimulated. The drive lines  101  can be stimulated by stimulation signals  107  provided by drive circuitry (not shown) and can include an alternating current (AC) waveform. The sense lines  103  can transmit touch or sense signals  109  indicative of a touch at the panel  100  to sense circuitry (not shown), which can include a sense amplifier for each sense line. 
     To sense a touch at the panel  100 , drive lines  101  can be stimulated by the stimulation signals  107  to capacitively couple with the crossing sense lines  103 , thereby forming a capacitive path for coupling charge from the drive lines  101  to the sense lines  103 . The crossing sense lines  103  can output touch signals  109 , representing the coupled charge or current. When a user&#39;s finger (or other object) touches the panel  100 , the finger can cause the capacitance Csig  111  to reduce by an amount ΔCsig at the touch location. This capacitance change ΔCsig can be caused by charge or current from the stimulated drive line  101  being shunted through the touching finger to ground rather than being coupled to the crossing sense line  103  at the touch location. The touch signals  109  representative of the capacitance change ΔCsig can be transmitted by the sense lines  103  to the sense circuitry for processing. The touch signals  109  can indicate the pixel where the touch occurred and the amount of touch that occurred at that pixel location. 
     While the embodiment shown in  FIG. 1  includes four drive lines  101  and five sense lines  103 , it should be appreciated that touch sensor panel  100  can include any number of drive lines  101  and any number of sense lines  103  to form the desired number and pattern of pixels  105 . 
     While various embodiments describe a sensed touch, it should be appreciated that the panel  100  can also sense a hovering object and generate hover signals therefrom. 
     In some embodiments, drive lines  101  can be dual gated, meaning that they can be driven from both sides of the row. In these embodiments, the ends of each row of drive line  101  can be coupled together to reduce the impedance of the drive lines  101  and to balance the panel. In some embodiments, as will be described in greater detail below, an FPC can be used to couple the ends of drive lines  101  together. Unlike drive lines  101 , sense lines  103  may not be dual gated, and thus, the ends of sense lines  103  may not be coupled together. 
     In the embodiments having dual gated drive lines  101 , it can be desirable to limit the length of drive lines  101  by coupling together the ends of each drive line using wires or traces having the shortest lengths possible. This can limit the impedance of each drive line, resulting in improved responses to touch events. 
     Additionally, when routing drive lines  101  and sense lines  103  within a device, it can be desirable to avoid intersecting or overlapping the wires or traces used to route sense lines  103  with the wires or traces used to route drive lines  101  outside of the active area (i.e., the pixel area) of the panel  100 . For example, it can be desirable to avoid situations where the wires or traces for drive lines  101  pass above or below the wires or traces for sense lines  103  (but do not make direct electrical contact with each other) outside of the active area. This can be done to avoid creating unwanted capacitances between the wires or traces, which can result in additional “pixels” being formed in areas away from the active area of the panel  100 . These unwanted pixels can generate false touch events and/or “negative touch events” on the panel  100 , in some instances when the user touches the device near the additional pixels and in other instances when no touch is occurring. 
     To prevent the formation of unwanted pixels in this way, a T-shaped FPC according to various embodiments can be used to route drive lines and sense lines of a touch sensor panel.  FIG. 2  illustrates an exemplary T-shaped FPC  201  that can be used to route drive lines and sense lines of a touch sensor panel that are similar or identical to drive lines  101  and sense lines  103  of touch sensor panel  100 . 
       FIG. 3  illustrates a top-view of an exemplary device  300 , such as a mobile phone, touchpad, portable computer, portable media player, or the like. Device  300  can include a touch sensor panel  100  for detecting touch events on the display of the device. In the example shown in  FIG. 3 , touch sensor panel  100  can include eight drive lines  101  and six sense lines  103 . However, it should be appreciated that a touch sensor panel  100  having any number of drive lines  101  and sense lines  103  can be used. 
     In some embodiments, one end of the drive lines  101  can be routed along an edge of device  300  to a first drive line output pad or contact portion  301 , while the other end of the drive lines  101  can be routed along an opposite edge of device  300  to a second drive line output pad or contact portion  303 . The first drive line contact portion  301  and second drive line contact portion  303  can include exposed segments of each of the drive lines  101  and can be used by an external device or connector, such as a flat cable or FPC (also referred to herein as a “flex circuit”), to couple to each end of the drive lines  101 . 
     In some embodiments, one end of a portion of the sense lines  103  can be routed to a first sense line output pad or contact portion  305 , while the remaining sense lines  103  can be routed to a second sense line output pad or contact portion  307 . Similar to the drive line contact portions  301  and  303 , sense line contact portions  305  and  307  can include exposed segments of the sense lines  103  and can be used by an external device or connector, such as a flat cable or FPC, to couple to an end of the sense lines  103 . While the example shown in  FIG. 3  includes three sense lines  103  routed to first sense line contact portion  305  and three sense lines  103  routed to the second sense line contact portion  307 , it should be appreciated that any number of sense lines  103  can be routed to any number of sense line contact portions. For example, in some embodiments, device  300  can include ten sense lines with all ten sense lines  103  being routed to a single sense line contact portion, while in other embodiments, device  300  can include nine sense lines with three sense lines being routed to each of three sense line contact portions. 
     Device  300  can further include an integrated circuit (IC)  309  for performing processing functions relating to device  300 . For example, in some embodiments, IC  309  can be used to control the display of device  300 . The drive lines  101  and sense lines  103  can be routed around IC  309  to contact portions  301 ,  303 ,  305 , and  307 . In other embodiments, contact portions  301 ,  303 ,  305 , and  307  can be located in different areas of device  300  depending on the location of IC  309 , with the drive lines  101  and sense lines  103  being appropriately routed around IC  309  to their corresponding contact portions. 
     Device  300  can further include IC FPC  311  (shown in  FIG. 3  as the grey strip connected to IC  309  and beneath T-shaped FPC  201 ) for coupling IC  309  to other components within device  300 . For example, IC FPC  311  can couple IC  309  to a printed circuit board located within device  300 . In some embodiments, IC FPC  311  can have a width that is smaller than the width of IC  309 , thereby allowing a more compact design of device  300 . 
     Device  300  can further include T-shaped FPC  201  for routing drive lines  101  and sense lines  103  of touch sensor panel  100 . T-shaped FPC  201  can include traces for coupling together the ends of drive lines  101  without intersecting or overlapping with traces coupled to sense lines  103 . As shown in  FIG. 3 , T-shaped FPC  201  can be attached to device  300  such that the crossbar of T-shaped FPC  201  extends beyond the contact portions  301 ,  303 ,  305 , and  307  towards touch sensor panel  100 . As will be discussed in greater detail below, this can allow the traces for drive lines  101  and the traces for sense lines  103  to be routed down towards touch sensor panel  100  before being routed through the neck of T-shaped FPC  201 . This FPC design can avoid intersections between traces for drive lines  101  and sense lines  103  within the FPC. In some embodiments, since the traces of T-shaped FPC  201  can be routed over conductive material formed on the thin film transistor (TFT) glass of device  300  located beyond the contact portions  301 ,  303 ,  305 , and  307  toward touch sensor panel  100 , an insulating material can be placed between the glass of device  300  and T-shaped FPC  201  to reduce or prevent electrical shorts between the conductive material formed on the glass of device  300  and T-shaped FPC  201 . 
     In some embodiments, T-shaped FPC  201  can be placed at least partially on IC FPC  311 . To illustrate,  FIG. 4  shows a cross-sectional view of device  300  cut along line  313 . As shown in  FIG. 4 , T-shaped FPC  201  can be placed above IC FPC  311  and IC  309 . In this way, T-shaped FPC  201  can couple to drive lines  101  and sense lines  103  at contact portions  301 ,  303 ,  305 , and  307 , without interfering with the coupling between IC  309  and IC FPC  311 . 
     In some embodiments, device  300  can include a grounded conductive material  401  placed between IC FPC  311  and T-shaped FPC  201  to reduce noise in T-shaped FPC  201  caused by the high frequency signals transmitted through IC FPC  311 . Grounded conductive material  401  can include a film of conductive material, such as silver or another metal. 
     In some embodiments, device  300  can further include stiffener  403  positioned on T-shaped FPC  201  above IC FPC  311  and IC  309 . Stiffener  403  can be used to limit the height of T-shaped FPC  201  by reducing the amount of bowing that can occur due to misalignment of the FPC on device  300 . For example, misalignment of T-shaped FPC  201  in the lateral direction can cause an increase in height of T-shaped FPC  201 . This can be undesirable since this can add to the thickness of device  300  or can cause pressure on an object, such as a touch panel or cover glass, placed above T-shaped FPC  201 . Stiffener  403  can be used to flatten T-shaped FPC  201  and reduce the effects of the lateral misalignment of the FPC. Stiffener  403  can include any rigid material, such as poly-imide (PI), stainless steel, copper, silver, or the like. In some embodiments, stiffener  403  can include a metal plate coupled to ground. 
     In some embodiments, T-shaped FPC  201  can include pre-bend sections  405  to further reduce the amount of bowing caused by misalignment of the FPC. Pre-bend sections  405  can include portions of T-shaped FPC  201  that are intentionally weakened in order to make the FPC more likely to bend at these locations. Pre-bend sections  405  can be positioned on portions of T-shaped FPC  201  to cause the FPC to conform to the shape of IC FPC  311  and IC  309  (or any other object positioned below T-shaped FPC  201 ). Additionally, pre-bend sections  405  can allow each end of T-shaped FPC  201  to be independently positioned during bonding, thereby preventing manufacturing tolerances from making one side of the bond successful while forcing the other to be misaligned. 
       FIG. 5  illustrates a more detailed view of T-shaped FPC  201  showing the traces for routing drive lines  101  and sense lines  103  of device  300  to an output of the FPC. In the illustrated example, the drive lines  101  and sense lines  103  are being routed to a connector pin  503  of, for example, a printed circuit board coupled to the output of T-shaped FPC  201 . The output of T-shaped FPC  201  can include exposed traces, connector pins, or any other appropriate coupling device. In some embodiments, T-shaped FPC  201  can include two layers of traces with vias  501  for routing the traces between the layers. In  FIG. 5 , the un-bolded solid lines represent traces located on the bottom layer of T-shaped FPC  201 , the dotted lines represent traces located on the top layer of T-shaped FPC  201 , and the large dots represent vias  501  connecting the bottom layer to the top layer. 
     In some embodiments, T-shaped FPC  201  can include drive line traces  509  for routing drive lines  101  from first drive line contact portion  301 , drive line traces  511  for routing drive lines  101  from second drive line contact portion  303 , sense line traces  513  for routing sense lines  103  from first sense line contact portion  305 , and sense line traces  515  for routing sense lines  103  from second sense line contact portion  307 . Thus, in these embodiments, T-shaped FPC  201  can include contact portions on the bottom side of the FPC to allow the traces  509 ,  511 ,  513 , and  515  to couple to the exposed segments of drive lines  101  and sense lines  103  at contact portions  301 ,  303 ,  305 , and  307  of device  300 . 
     As shown in  FIG. 5 , sense line traces  513  and  515  can be routed to connector pin  503  through the bottom layer and along the outer portion of the neck of T-shaped FPC  201 . Routing the sense line traces  513  and  515  in this way can leave open a channel at the crossbar portion of T-shaped FPC  201  (bottom of  FIG. 5 ) through which the drive line traces  509  and  511  can couple together the drive lines  101  from first drive line contact portion  301  and second drive line contact portion  303 . Additionally, a channel can be left open at the center of T-shaped FPC  201  through which the coupled drive line traces  509 / 511  can be routed to connector pin  503 . 
     In some embodiments, as shown in  FIG. 5 , a portion of the drive line traces  509  and  511  (e.g., half of the drive line traces  509  and  511 ) located at the outer ends of T-shaped FPC  201  (left and right sides of  FIG. 5 ) can be routed towards the touch sensor panel  100  of device  300  (bottom of  FIG. 5 ) where they can be routed up to the top layer of T-shaped FPC  201  through vias  501 . From there, the outer drive line traces  509  and  511  can be routed together towards the center of T-shaped FPC  201  where all but one pair of drive line traces  509  and  511  can be coupled together by a second set of vias  501 . In the embodiment shown in  FIG. 5 , the vias  501  coupling together the outer drive line traces  509  and  511  can be arranged in a linear fashion. However, in other embodiments, the vias  501  can be arranged in a staggered fashion, as illustrated by the vias  501  located at the left-middle portion of  FIG. 5 . The combined outer drive line traces  509 / 511  from the second set of vias  501  can then be routed through the bottom layer at the center of T-shaped FPC  201  to connector pin  503 , while the remaining pair of drive line traces  509  and  511  can be coupled together near the second set of vias  501  and routed through the top layer at the center of T-shaped FPC  201  to connector pin  503  where they can be routed to the bottom layer through a via  501  and coupled to connector pin  503 . While all but one pair of outer drive line traces  509  and  511  are shown as being coupled together by the second set of vias  501 , in some embodiments, all pairs of outer drive line traces  509  and  511  can be coupled together by vias  501  at the second set of vias  501  in a manner similar to that shown in  FIG. 5 . 
     In some embodiments, the remaining drive line traces  509  and  511  (e.g., the remaining half of drive line traces  509  and  511 ) located at the inner portion of T-shaped FPC  201  can be routed towards the touch sensor panel  100  of device  300  (bottom of  FIG. 5 ). From there, the inner drive line traces  509  and  511  can be routed towards the center of T-shaped FPC  201  through the bottom layer where all but one pair of drive line traces  509  and  511  can be coupled together by a third set of vias  501 . In the embodiment shown in  FIG. 5 , the vias  501  coupling together the inner drive line traces  509  and  511  can be arranged in a staggered fashion. However, in other embodiments, the vias  501  can be arranged in a linear fashion, as illustrated by the vias  501  located at the right-middle middle portion of  FIG. 5 . The combined inner drive line traces  509 / 511  from the third set of vias  501  can then be routed through the top layer at the center of T-shaped FPC  201  towards connector pin  503 , where the combined inner drive line traces  509 / 511  can then be routed down to the bottom layer of T-shaped FPC  201  through another set of vias  501 . The remaining pair of drive line traces  509  and  511  can be coupled together near the third set of vias  501  and routed through the bottom layer at the center of T-shaped FPC  201  to couple to connector pin  503 . While all but one pair of inner drive line traces  509  and  511  are shown as being coupled together by the third set of vias  501 , in some embodiments, all pairs of inner drive line traces  509  and  511  can be coupled together by vias  501  at the third set of vias  501  in a manner similar to that shown in  FIG. 5 . 
     As illustrated by  FIG. 5 , drive lines  101  and sense lines  103  can be coupled to connector pin  503  using T-shaped FPC  201  without the traces for drive lines  101  and sense lines  103  intersecting or overlapping. For example, drive line traces  509  and  511  may not cross paths with sense line traces  513  or  515  on the same or different layer of T-shaped FPC  201 . This can reduce or prevent the formation of unwanted parasitic capacitance between drive line traces  509  and  511  and sense line traces  513  or  515  that can result in false touch events and/or negative touch events due to the formation of additional pixels away from the active area of the panel  100 . While drive line traces  509  or  511  may overlap with other drive line traces  509  or  511 , the formation of parasitic capacitance between drive line traces  509  or  511  may not result in the formation of additional pixels away from the active area of the panel  100  in the same way. Additionally, the ends of drive lines  101  can be coupled together by drive line traces  509  and  511  using relatively short trace lengths, thereby reducing the overall impedance of the drive lines  101 . 
     In some embodiments, T-shaped FPC  201  can further include guard traces  505  positioned between the drive line traces and sense line traces for reducing the capacitances between the sense line traces  513  and drive line traces  509 , and between sense line traces  515  and drive line traces  511 . In some embodiments, guard traces  505  can be coupled to ground and can include a conductive material, such as silver or other metal. 
     While T-shaped FPC  201  was described above as having traces for eight drive lines  101  and six sense lines  103 , it should be appreciated that the configuration shown in  FIG. 5  can be extended to any number of drive lines  101  and sense lines  103 . For instance, any number of sense line traces  513  and  515  can be routed along the outer edge of T-shaped FPC  201  to allow coupling between any number of drive line traces  509  and  511  and to allow the coupled drive line traces  509 / 511  to be routed through the center of the T-shaped FPC  201  to connector pin  503 . Additionally, the outer drive line traces  509  and  511  can be coupled together on one of the layers (e.g., the top layer) of T-shaped FPC  201 , while the remaining inner drive line traces  509  and  511  can be coupled together on the other layer (e.g., the bottom layer) of T-shaped FPC  201 . The coupled inner and outer drive line traces  509 / 511  can then be routed to the opposite layer through a set of vias  501  arranged in either a staggered fashion or a linear fashion. From there, the drive lines  501  can be routed towards connector pin  503  where they can be routed to the bottom layer of T-shaped FPC  201  and coupled to the corresponding pins of connector pin  503 . 
       FIG. 6  illustrates another embodiment of T-shaped FPC  201  in which one or more pairs (e.g., the outermost drive line traces  509  and  511  corresponding to the bottom drive line  101  row of panel  100 ) of drive line traces  509  and  511  may not be coupled together, thereby leaving a corresponding row of drive lines  101  uncoupled within T-shaped FPC  201 . This can be done to allow measurement of the impedance of the one or more uncoupled drive lines  101  for quality control purposes. For example, if the measured impedance is high, this can indicate that the touch response of touch sensor panel  100  may be poor, while a low impedance can indicate that an electrical short may be present in the device. While problems associated with other drive lines  101  may not be detected by measuring the impedance of the one or more uncoupled drive lines  101 , the one or more uncoupled drive lines  101  can provide a way to quickly compare touch sensor panels  100  that would not otherwise be available. 
     In some embodiments, the one or more uncoupled drive lines  101  can be coupled together in a location other than in the T-shaped FPC  201 . For example, the ends of the one or more uncoupled drive lines  101  can be coupled together on a printed circuit board coupled to the output end of T-shaped FPC  201 . 
       FIG. 7  shows another exemplary embodiment of device  300  in which T-shaped FPC  201  can be incorporated into the LCD FPC  705 . LCD FPC  705  can be coupled to the TFT glass  703  of device  300  and LCD backlight assembly  707 . In these embodiments, LCD FPC  705  can include the already existing traces used for the LCD display, as well as the components of T-shaped FPC  201  with the exemplary trace routing described above. By incorporating the architecture of T-shaped FPC  201  into LCD FPC  705 , the number of FPCs used in device  300  can be reduced. 
       FIG. 8  shows an exemplary process  800  for routing rows of drive lines and columns of sense lines. At block  801  of process  800 , a set of drive lines can be routed to an output using a first set of traces. The drive lines can be part of a touch sensor panel and can be operable to receive an AC stimulation signal for detecting touch events on the panel. For example, the drive lines can be similar or identical to drive lines  101  of touch sensor panel  100 . 
     In some embodiments, the first set of traces can be included within a T-shaped FPC that is similar or identical to T-shaped FPC  201 . Additionally, in some embodiments, the ends of the drive lines can be coupled together by the first set of traces before reaching the output. For example, the drive lines can be coupled together by a first set of traces that is similar or identical to drive line traces  509  and  511 . 
     At block  803 , a set of sense lines can be routed to an output using a second set of traces. The sense lines can be part of a touch sensor panel and can intersect or overlap with the drive lines to form pixels within the touch sensor panel. The sense lines can further be operable to transmit touch or sense signals indicative of a touch event occurring on the panel. For example, the sense lines can be similar or identical to sense lines  103  of touch sensor panel  100 . 
     In some embodiments, the second set of traces can be included within a T-shaped FPC that is similar or identical to T-shaped FPC  201 . In some embodiments, the sense lines can be routed to the output without overlapping or intersecting with the first set of traces used to route the drive lines. For example, the sense lines can be routed by a second set of traces that is similar or identical to sense line traces  513  and  515 . 
     A T-shaped FPC as described above with respect to in  FIGS. 2-8  can be incorporated into a mobile phone, a digital media player, a portable computer, touch pad, display device, PCB, and other suitable devices. 
     Although embodiments have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the various embodiments as defined by the appended claims.

Metadata:
Filing Date: 20110621
Publication Date: 20140429
Grant Date: 20140429
Priority Date: 20110621
Inventors: HOTELLING STEVEN PORTER
WURZEL JOSHUA G.
MARTISAUSKAS STEVEN J.
MILLER THAYNE M.
SUNG KUO-HUA
Assignee: APPLE INC
CPC Classifications: [{"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/147", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/147", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/147", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1658", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1658", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1658", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/028", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/40", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46545241