Abstract:
A system for controlling a boundary of spreading liquid adhesive on a surface is disclosed. The system includes one or more ultra-violet (UV) sources configurable to emit UV light onto the liquid adhesive; and a control circuit coupled to the one or more UV sources and configured to control the one or more UV sources to selectively apply the UV light at selected locations on the liquid adhesive to cure the adhesive and prevent its further spread at those locations.

Description:
FIELD  
       [0001]    This relates generally to the fabrication of circuit panels, and more particularly, to controlling the boundary of liquid adhesive during lamination. 
       BACKGROUND 
       [0002]    Electronic devices can generally include at least one substrate with another substrate and/or electrical components adhered thereto. Fabrication of substrates can involve applying an adhesive to a surface of a substrate and using the applied adhesive to adhere another substrate and/or electrical component to the substrate surface. Liquid adhesive is sometimes preferred because of its flowability and compliance, which allows the adhesive to easily cover many different substrate configurations. However, liquid adhesive&#39;s flowability can also be problematic because of the difficulty in controlling its boundary as it spreads between two substrates under pressure. Any overflow or underfill of the liquid adhesive during fabrication could cause certain defects in the final product. For example, if the adhesive overflows a designated boundary, it could interact with other layers or components of the device, and produce unintended effects in the device being fabricated. Similarly, if the liquid adhesive underfills a desired area, i.e., if the adhesive fails to reach the intended boundary, it may result in defects such as visible lines in the display area of the device. 
         [0003]    Currently, very few boundary control mechanisms exist for controlling the spread of liquid adhesive during manufacturing. One common way to deal with overflow is to simply remove the excess adhesive that has overflowed the intended boundary. However, if the cleaning is not done thoroughly, there could be residue left in the laminate that could affect the quality of the overall device. Sometimes, the laminate can be contaminated if the cleaning is not carried out properly. There may be design constraints or post-lamination processes that prohibit cleaning once the substrates are laminated together. For example, there may not be enough room between the laminated substrates for the cleaning tools to reach the overflowed adhesive. Therefore, it is desirable to have a better mechanism to control the boundary of liquid adhesive to avoid overflow and underfill during fabrication. 
       SUMMARY  
       [0004]    This relates to controlling the boundary of spreading liquid adhesive to prevent overflow and/or underfill from occurring during fabrication of electronic devices. In particular, a UV emitter can be used to pre-cure or full-cure (both referred to simply as “cure” in the remaining portion of this disclosure) liquid adhesive spreading over a surface of a substrate. A segmented shutter or mask can be positioned between the UV emitter and the liquid adhesive to selectively block the UV light from reaching the liquid adhesive at various times and/or locations. In the areas where the liquid adhesive is exposed to the UV light, the liquid adhesive can be cured instantly, thus preventing the adhesive from spreading further. In contract, in the areas where the UV light is blocked by the shutter, the liquid adhesive can continue to spread until either reaching a UV-exposed area or until equilibrium is reached. In some embodiments, a monitoring system can be equipped to monitor the movement of the liquid adhesive in real time. Based on the observed movement pattern, a controller can actively open and close individual segments of the shutter to direct UV light onto the areas where the adhesive has reached an intended boundary. This process can continue until the liquid adhesive fills the area defined by this boundary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIGS. 1   a - 1   e  illustrate a typical lamination process during device fabrication, and the change in the spread pattern of the liquid adhesive used in the process. 
           [0006]      FIG. 2  illustrates an exemplary setup of a UV emitter and segmented shutter for controlling the boundary of liquid adhesive during lamination according to embodiments of the disclosure. 
           [0007]      FIG. 3  is a partial top view illustrating the spread pattern of liquid adhesive over a surface of a substrate and the controlled boundary of the adhesive according to embodiments of the disclosure. 
           [0008]      FIG. 4  illustrates another exemplary setup of a UV emitter and segmented shutter for controlling the boundary of liquid adhesive during lamination according to embodiments of the disclosure. 
           [0009]      FIG. 5  illustrates yet another exemplary setup of a UV emitter and segmented shutter for controlling the boundary of liquid adhesive during lamination according to embodiments of the disclosure. 
           [0010]      FIG. 6  illustrates using an array of individually controlled UV emitters to control the boundary of liquid adhesive during lamination according to embodiments of the disclosure. 
           [0011]      FIG. 7  is a block diagram illustrating exemplary components of an active shutter control system for controlling the boundary of spreading liquid adhesive during lamination according to embodiments of the disclosure. 
           [0012]      FIG. 8  is a block diagram illustrating exemplary components of a time-based shutter control system for controlling the boundary of spreading liquid adhesive during lamination according to embodiments of the disclosure. 
           [0013]      FIG. 9   a  illustrates an exemplary digital media player including panels laminated using liquid adhesive, the boundary of which is controlled according to embodiments of the disclosure. 
           [0014]      FIG. 9   b  illustrates an exemplary mobile telephone including panels laminated using liquid adhesive, the boundary of which is controlled according to embodiments of the disclosure. 
           [0015]      FIG. 9   c  illustrates an exemplary mobile computer including panels laminated using liquid adhesive, the boundary of which is controlled according to embodiments of the disclosure. 
           [0016]      FIG. 9   d  illustrates an exemplary desktop computer including panels laminated using liquid adhesive, the boundary of which is controlled according to embodiments of the disclosure. 
           [0017]      FIG. 10  illustrates an exemplary computing system including a touch sensor panel laminated to another panel or components using liquid adhesive, the boundary of which is controlled according to embodiments of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    In the following description of preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific embodiments in which the disclosure can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the embodiments of this disclosure. 
         [0019]    This relates to controlling the boundary of spreading liquid adhesive to prevent overflow and/or underfill from occurring during fabrication of electronic devices. In particular, a UV emitter can be used to pre-cure or full-cure (both referred to simply as “cure” in the remaining portion of this disclosure) liquid adhesive spreading over a surface of a substrate. A segmented shutter or mask can be positioned between the UV emitter and the liquid adhesive to selectively block the UV light from reaching the liquid adhesive at various times and/or locations. In the areas where the liquid adhesive is exposed to the UV light, the liquid adhesive can be cured instantly, thus preventing the adhesive from spreading further. In contract, in the areas where the UV light is blocked by the shutter, the liquid adhesive can continue to spread until either reaching a UV-exposed area or until equilibrium is reached. In some embodiments, a monitoring system can be equipped to monitor the movement of the liquid adhesive in real time. Based on the observed movement pattern, a controller can actively open and close individual segments of the shutter to direct UV light onto the areas where the adhesive has reached an intended boundary. This process can continue until the liquid adhesive fills the area defined by this boundary. 
         [0020]      FIGS. 1   a - 1   e  illustrate a typical lamination process during device fabrication and the change in the spread pattern of the liquid adhesive used in the process. These figures illustrate both overflow and underfill of the adhesive due to the non-uniform spread of the adhesive when pressed between two substrates. The substrates illustrated in these figures and subsequent figures can be rigid (e.g., glass) or flexible (e.g., plastic). They can be the base substrates from which various layers such as the display layer and the touch panel layers of the device are made. 
         [0021]      FIG. 1   a . illustrates an exemplary initial dispense pattern  100  of liquid adhesive on a surface of a first substrate  102 . The initial dispense pattern  100  can be in any shape or form. However, as detailed later in this disclosure, the initial pattern  100  can be optimized to develop a relatively predictable spread pattern of the adhesive during the lamination process. For example, the double-Y dispense pattern  100  shown in  FIG. 1   a  has been found to be one of the more optimal dispense patterns for producing a relatively even spread pattern of the adhesive. 
         [0022]      FIG. 1   b  provides a side view of the first substrate  102  of  FIG. 1   a . As illustrated, the layer of liquid adhesive  100  is deposited on top of the first substrate  102 . During lamination process, the first substrate  102  can be aligned with a second substrate  104  such that the adhesive  100  on the first substrate is facing the bottom surface of the second substrate  104 . The two substrates  102 ,  104  can be brought towards and pressed against each other to form a sandwich. As illustrated in  FIG. 1   c , when the two substrates  102 ,  104  are pressed against each other, the liquid adhesive  100  naturally starts to spread outward towards the edges of the substrates. 
         [0023]    Although the initial dispense pattern may somewhat dictate how the liquid adhesive  100  spreads when squeezed by the two substrates  102 ,  104 , due to the random nature of the way liquid flows and other factors such as the geometric and surface condition of the substrate, the liquid adhesive  100  is unlikely to spread in a completely uniform and predictable manner that maintains the initial dispense pattern. As shown in the top view of  FIG. 1   d , the overall pattern of the liquid adhesive  100 , as it spreads outward, can be substantially different from the initial double-Y pattern shown in  FIG. 1   a.    
         [0024]    Conventionally, a UV emitter can be turned on after the liquid adhesive has been spreading for a certain period of time. The UV light from the emitter can cure the liquid adhesive, stopping it from spreading further. This period of time typically corresponds to the duration it takes for the adhesive to spread from the initial dispense pattern to the edge area of the substrate and can usually be determined via repeated trials. When the UV emitter is turned on, the entire layer of liquid adhesive is usually exposed to the UV light and cured at the same time. Because of the non-uniform movement of the liquid adhesive  100 , when the adhesive is exposed to UV light, the boundary of the cured adhesive will likely not conform to any particular shape. 
         [0025]    Ideally, the boundary of the cured adhesive should be uniform and without any overflow or underfill areas. For example,  FIG. 1   e  illustrates a band  106  (shown in dotted lines) marking an ideal area within which the boundary of the liquid adhesive should be located when the adhesive is cured. The width of the band  106  can vary in different types of devices. In smaller devices such as smartphones, the band  106  can be very narrow due to the already narrow edge area around the screen. Thus, conventional methods such as cleaning the overflow area may be difficult, if not impossible, to perform. More precise boundary control mechanisms are needed. 
         [0026]    As shown in  FIG. 1   e , the actual boundary of the cured liquid adhesive  100  is unlike to fall completely within the band  106  due to the uncontrolled spread of the adhesive  100 . As a result, the liquid adhesive  100  may overflow pass the band  106  in some areas  108  while failing to reach the band in other areas  110 . As discussed above, this non-uniform spread (i.e., overflow or underfill) of the liquid adhesive can result in various defects in the final product. The embodiments discussed below address this issue by providing various mechanisms to control the boundary of liquid adhesive as it spreads between two substrates. 
         [0027]    In the embodiments of this disclosure, instead of exposing the entire liquid adhesive layer to UV light at the same time, various mechanisms are developed to selectively expose certain boundary areas of the adhesive to UV light to stop further advance of the liquid adhesive in those areas while blocking the UV light in other areas to allow the adhesive to continue to spread freely. More specifically, the areas that would typically overflow can be UV-cured sooner than those areas that would typically underfill. As a result, the final boundary of the liquid adhesive can be substantially uniform (e.g., in straight lines), when completely cured. 
         [0028]    In one embodiment, a segmented shutter can be positioned between the UV emitter and the liquid adhesive.  FIG. 2  illustrates an exemplary UV emitter  200  with a segmented shutter  202  positioned directly over a stack of two substrates  206 ,  208  being laminated together by the liquid adhesive  210  between them. In this embodiment, the top substrate  206  can be transparent. The segmented shutter  202  can include a number of segments  212 - 218 , each of which can be individually opened or shut to control the UV emission  204  from the emitter  200 . In various embodiments, the segments of the shutter can be controlled mechanically, electronically, or by any suitable means. Although the shutter  202  is shown to have seven rectangular segments  212 - 218 , it should be understood that the number of segments and the shape and size of the segments can vary in different embodiments. For example, a large number of smaller segments may be optimal if fine control of the adhesive boundary is desired. The number of segments can also depend on the size of the substrates  206 ,  208  and the amount of liquid adhesive  210  dispensed. 
         [0029]    As illustrated, some of the segments  212 ,  214 ,  215 ,  218  can be shut to block the UV light from the UV emitter  200  from reaching the areas of the liquid adhesive directly under those segments  202 . As a result, the liquid adhesive  210  in those areas is not cured and can continue to move freely. In contrast, segments  213 ,  216 ,  217  can be in a open position to allow the UV light to pass through onto the liquid adhesive  210  in the areas directly below these segments  213 ,  216 ,  217 . The liquid adhesive in the area under segments  213 ,  216 ,  217  can thus be cured by the UV light and stop spreading further. 
         [0030]    To control the boundary of the liquid adhesive as it spreads, the segments  212 - 218  of the shutter  202  can be aligned with a band marking the desired boundary in the border area of one of the substrates  206 ,  208 , although in other embodiments, a two-dimensional array of shutter segments (not shown) can also be employed for additional shape control over the boundary of the cure adhesive.  FIG. 3  provides a partial top view the stacked structure of  FIG. 2 . The sections  312 - 318  along the border area  302  of the substrate can sections of the band marking the desired boundary of the adhesive. Each section  312 - 318  can be aligned directly under a corresponding segment  213 - 218  of the shutter above. As illustrate, the liquid adhesive  300  has spread into the border area  302  in a few sections  313 ,  316 ,  317 . In response, the corresponding segments  213 ,  216 ,  217  of the shutter (shown in  FIG. 2 ) can be opened to allow the UV light from the emitter  200  to reach these sections  313 ,  316 ,  317 . The UV light can in turn cure the adhesive almost instantly in these sections  313 ,  316 ,  317  and thus prevent it from spreading further into the border area  302 . 
         [0031]    In contrast, the segments  212 ,  214 ,  215 ,  218  of the shutter located above sections  312 ,  314 ,  315 ,  318  can remain shut because the adhesive  300  has not reached these sections  312 ,  314 ,  315 ,  318  of the border area  302 . Therefore, sections  312 ,  314 ,  315 ,  318  are not exposed to UV light and the adhesive can continue to spread further in the direction of these sections  312 ,  314 ,  315 ,  318 . When the adhesive finally spreads into the border area in one or more of these sections  312 ,  314 ,  315 ,  318 , the corresponding segments of the shutter can be opened and allow the UV light to pass through. By UV-curing liquid adhesive only in the areas that have reached the band marking a desired boundary, the embodiments disclosed herein can provide more precise mechanisms to form a more uniform boundary of liquid adhesive in lamination processes. 
         [0032]    Although  FIGS. 2 and 3  illustrate that the UV emitter  200  and the shutter  202  are positioned in a top down position directly above the stacked structure, it should be understood that they can be implemented in any orientation. For example,  FIG. 4  illustrates a UV emitter  400  with a segmented shutter  412  positioned obliquely with respect to the surface of the stacked substrates  406 ,  408  and adhesive layer  410  between them. The top substrate  406  can be transparent. As in the previous embodiment, the UV light from the emitter  400  can be directed to a band marking a desired boundary of the liquid adhesive. Because the UV light can reach the liquid adhesive at an angle (when the segments of the shutter are open), the band marking the desired boundary of the liquid adhesive can be slightly closer to the edge or slightly farther away from the edge of the substrates. In some embodiments, it is preferable to have the band located closer to the edge of the substrates to allow the liquid adhesive to advance a bit further, passing the inner boundary of the border area. This can better hide the boundary line of the adhesive underneath the border area which is often opaque so that even when a user is viewing the screen at an oblique angle, the boundary line would not be visible. 
         [0033]      FIG. 5  illustrates another embodiment in which the UV emitter  500  and the segmented shutter  502  can be positioned facing the side of the stacked structure  520 . This can allow the UV light from the emitter  500  to reach the liquid adhesive layer  510  even if both substrates  506 ,  508  are opaque. In this embodiment, a set of UV emitters and shutters may need to be positioned at all four sides of the stacked structure  520 . In another embodiment, the UV emitter and the segmented shutter can be positioned facing the bottom of the stacked structure. 
         [0034]    Although the above-described embodiments all require at least one UV emitter and a shutter with multiple independent segments to control the boundary of liquid adhesive, it should be understood that the same effect can be achieved by using an array of independent UV emitters that can be individually turned on and off. As illustrated in  FIG. 6 , the array of UV emitters (collectively  600 ) can be aligned over the top of the border area of the stacked structure  620 . Each of the emitters  600  can be turned on or off according to the spread pattern of the adhesive. When an emitter is turned on, UV light can be emitted onto the section in the border area directly underneath the emitter.  FIG. 6  shows three of the emitters  600  are turned on and the areas of the adhesive  610  under these emitters can be exposed to UV light from these emitters  600  and be cured. In this embodiment, no segmented shutter may be required. 
         [0035]    Another aspect of this disclosure relates to control mechanisms for the segmented shutter (or a UV emitter array such as the one shown in  FIG. 6 ). In one embodiment the spread of the liquid adhesive can be monitored by a detection module in real time. Based on the observed progression of the boundary of the adhesive, a controller can actively open or shut one or more segments of the shutter (or turn on or off one or more of the emitters in the array) to dynamically control UV curing of the adhesive in different areas.  FIG. 7  is a block diagram illustrating the components of an exemplary active shutter control system  700 . As illustrated, the active shutter control system  700  can include a UV source  706  equipped with segmented shutter (not shown separately) such as those shown in  FIGS. 2 ,  4 , and  5 . The UV source  706  can be positioned to emit UV light to the liquid adhesive in a laminate  702 . As mentioned above, the liquid adhesive can be cured when exposed to UV light. 
         [0036]    The active shutter control system  700  can include a detection module  704  that can monitor the spread of the liquid adhesive in the laminate  702  in real time. The detection  700  module can be an optical detection system. In one embodiment, the detection module can include a camera capable of tracking the flow of the adhesive. If the top substrate is transparent, the camera can be positioned over the top of the laminate  702  to capture an overhead view of progression of the liquid adhesive. In particular, the camera can capture where the boundary of the liquid adhesive is at a particular time. Alternatively, if the top substrate is opaque, the camera can be positioned on the side of the laminate. The boundary of the adhesive can be determined based on the focal length of the lens of camera. In other embodiments, the detection module can be designed to detect the moving boundary of the liquid adhesive by other means such as the optical properties of the adhesive. For example, if the adhesive can reflect a certain amount of infrared (IR) light, an IR transmitter/receiver array can be used to emit IR light and detect when IR light is being reflected off of adhesive appearing in a boundary section of the laminate. 
         [0037]    The detection module  704  can be connected to a controller such as a programmable logic controller (PLC)  708 . In some embodiments, the detection module  704  can feed, either continuously or at preset time intervals, the detected spread pattern of the liquid adhesive as captured by a camera or other means to the PLC  708 . The PLC  708  can include firmware/software for analyzing the spread pattern to determine whether the boundary of the liquid adhesive has reached a predetermined band marking the desired boundary, such as the one shown in  FIG. 1   e . If it has, the PLC  708  can further determine the specific sections of the band into which the liquid adhesive has spread. As illustrated in  FIG. 7 , the PLC  708  can be connected to the segmented shutter of the UV source  706 . If breach into one or more of the sections of the band is detected and the sections identified, the PLC  708  can actively open the corresponding segment(s) of the shutter to initiate UV curing of the liquid adhesive in those sections. This in turn prevents the liquid adhesive from spreading beyond the band, thus effectively preventing overflow from occurring. As the liquid adhesive continue to reach the band in various sections, the PLC  708  can dynamically open and close the corresponding segments of the shutter of the UV source  706  to form a desired boundary of the liquid adhesive when it is cured. 
         [0038]    Because the active shutter control system  700  can monitor the flow of the liquid adhesive in real time and quickly adjust the segments of the shutter in response to the monitored flow, and because liquid adhesive can be UV cured almost instantaneously, precise boundary control can be achieved where the final boundary of the UV-cured liquid adhesive can substantially conform to the predetermined boundary band. 
         [0039]    While the active shutter control system  700  does not directly prevent underfill, underfill is relatively easy to fix and can be eliminated by optimizing the initial dispense pattern of the liquid adhesive. More specifically, even though the exact spread pattern of the adhesive may be difficult to predict, the spread pattern from the same initial dispense pattern can be relatively consistent and thus predictable to some extent. For example, the double-Y dispense pattern shown in  FIG. 1  a may consistently spread in a pattern similar to the one shown in  FIG. 1   d . Thus, the initial dispense pattern of the adhesive can be designed, through trial, to guarantee that the adhesive can at the minimum reach the predetermined boundary band in all directions. This in combination with the active shutter control system of  FIG. 7  can prevent both underfill and overflow from occurring. 
         [0040]    In another embodiment, using the same principle described in the last paragraph, a time-based mechanism can be used for controlling the shutter of a UV source to control the boundary of liquid adhesive during lamination. This can work effectively, especially for a repeating pattern of spreading. As discussed above, a general and relatively consistent spread pattern can be determined from an initial dispense pattern based on repeated trials. Accordingly, a time duration from the initial dispense of the liquid adhesive until the edge of the adhesive reaches each section of the predetermined boundary band can be recorded. In some embodiments, the start of the time duration can be set to when the second substrate is pressed onto the liquid adhesive, effectively starting the spread of the adhesive. 
         [0041]      FIG. 8  illustrates a time-based shutter control system for controlling the boundary of the spreading liquid adhesive. The time-based shutter control system  800  can include a UV source  806  with a segmented shutter (not shown separately) for emitting UV light to a laminate  802  including a layer of liquid adhesive. The system  800  can also include a controller such as a PLC ( 808 ) for controlling the individual segments of the shutter. However, this embodiment is different from the one shown in  FIG. 7  in that the time-based shutter control system  800  does not include a detection module for monitoring the spreading of the liquid adhesive in real time. Instead of controlling the shutter based on the real-time flow pattern of the adhesive, the PLC  808  in this embodiment can be programmed to open and shut each segment of the shutter at various times based on the known spread pattern of the adhesive from a particular initial dispense pattern. For example, some of the segments of the shutter can be opened early to allow UV to reach areas where the adhesive is known to spread the fastest based on the normal spread pattern from the particular initial dispense pattern. Other segments of the shutter can be programmed to open at later times because these segments are over areas where spreading has been empirically determined to be slower based on the same known spread pattern. The PLC  808  can be synchronized with the initial dispense of the adhesive or the start of the lamination process using a timer  810 . 
         [0042]    The time-based shutter control system  800  can be relatively simple and inexpensive to implement because no detection module is required to monitor the spread of the liquid adhesive. It can achieve the same level of boundary control as the active shutter control system, particularly for a repeating pattern of spreading that is relatively consistent and predictable. 
         [0043]    In some embodiments, as an alternative to the segmented shutter, one or more static masks designed based on the known spread pattern can be inserted and removed between the UV source and the liquid adhesive to achieve the same boundary control effects based on the same concept discussed above. 
         [0044]      FIG. 9   a  illustrates exemplary digital media player  910  that can include a screen  915  including multiple panels such as a touch sensor panel, display panel, cover glass that are laminated using liquid adhesive wherein the boundary of the liquid adhesive can be controlled according to embodiments of the disclosure. 
         [0045]      FIG. 9   b  illustrates exemplary mobile telephone or tablet  920  that can include a screen  925  including multiple panels such as a touch sensor panel, display panel, cover glass that are laminated using liquid adhesive wherein the boundary of the liquid adhesive can be controlled according to embodiments of the disclosure. 
         [0046]      FIG. 9   c  illustrates an exemplary personal computer  944  that can include touch sensor panel  924  and display device  930 . The touch sensor panel  924  and the display device can include one or more panels laminated using liquid adhesive wherein the boundary of the liquid adhesive can be controlled according to embodiments of the disclosure. 
         [0047]      FIG. 9   d  illustrates a desktop computer  990  including a display device  992 . The display device  992  and a virtual keyboard  994 , both of which can include one or more panels laminated using liquid adhesive wherein the boundary of the liquid adhesive can be controlled according to embodiments of the disclosure. 
         [0048]      FIG. 10  illustrates exemplary computing system  1000  that can include one or more touch sensor panels laminated to a display panel, a cover glass, or another component using liquid adhesive. The boundary of the liquid adhesive can be controlled during fabrication according to the embodiments of the disclosure described above. Computing system  1000  can include one or more panel processors  1002  and peripherals  1004 , and panel subsystem  1006 . Peripherals  1004  can include, but are not limited to, random access memory (RAM) or other types of memory or storage, watchdog timers and the like. Panel subsystem  1006  can include, but is not limited to, one or more sense channels  1008 , channel scan logic  1010  and driver logic  1014 . Channel scan logic  1010  can access RAM  1012 , autonomously read data from the sense channels and provide control for the sense channels. In addition, channel scan logic  1010  can control driver logic  1014  to generate stimulation signals  1016  at various frequencies and phases that can be selectively applied to drive lines of touch sensor panel  1024 . In some embodiments, panel subsystem  1006 , panel processor  1002  and peripherals  1004  can be integrated into a single application specific integrated circuit (ASIC). 
         [0049]    Touch sensor panel  1024  can include a capacitive sensing medium having a plurality of drive lines and a plurality of sense lines, although other sensing media can also be used. Either or both of the drive and sense lines can be coupled to a thin glass sheet according to embodiments of the disclosure. Each intersection of drive and sense lines can represent a capacitive sensing node and can be viewed as picture element (pixel)  1026 , which can be particularly useful when touch sensor panel  1024  is viewed as capturing an “image” of touch. (In other words, after panel subsystem  1006  has determined whether a touch event has been detected at each touch sensor in the touch sensor panel, the pattern of touch sensors in the multi-touch panel at which a touch event occurred can be viewed as an “image” of touch (e.g. a pattern of fingers touching the panel).) Each sense line of touch sensor panel  1024  can drive sense channel  1008  (also referred to herein as an event detection and demodulation circuit) in panel subsystem  1006 . 
         [0050]    Computing system  1000  can also include host processor  1028  for receiving outputs from panel processor  1002  and performing actions based on the outputs 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 coupled 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  1028  can also perform additional functions that may not be related to panel processing, and can be coupled to program storage  1032  and display device  1030  such as an LCD panel for providing a UI to a user of the device. Display device  1030  together with touch sensor panel  1024 , when located partially or entirely under the touch sensor panel, can form touch screen  1018 . 
         [0051]    Note that one or more of the functions described above can be performed by firmware stored in memory (e.g. one of the peripherals  1004  in  FIG. 10 ) and executed by panel processor  1002 , or stored in program storage  1032  and executed by host processor  1028 . The firmware can also be stored and/or transported within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer-readable storage medium” can be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
         [0052]    The firmware can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
         [0053]    Although embodiments of this disclosure have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of embodiments of this disclosure as defined by the appended claims.