# Patent

## Title
Touch screen stack-ups

## Abstract

A multi-touch sensor panel is disclosed that can include a glass subassembly having a plurality of column traces of substantially transparent conductive material that can be formed on the back side, wherein the glass subassembly can also act as a cover that can be touched on the front side. Row traces of the same or different substantially transparent conductive material can then be located near the column traces, and a layer of dielectric material can be coupled between the column traces and the row traces. The row and column traces can be oriented to cross over each other at crossover locations separated by the dielectric material, and the crossover locations can form mutual capacitance sensors for detecting one or more touches on the front side of the glass subassembly.

## Background
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Patent Application No. 60/878,783, filed on Jan. 5, 2007, the entire disclosures of which are incorporated herein by reference for all intended purposes.


FIELD OF THE INVENTION
This relates to touch screens, and more particularly, to the stack-up of materials comprising the touch screens.
BACKGROUND OF THE INVENTION
Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, touch panels, joysticks, 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 panel, which can be a clear panel with a touch-sensitive surface. The touch panel can be positioned in front of a display screen so that the touch-sensitive surface covers the viewable area of the display screen. Touch screens can allow a user to make selections and move a cursor by simply touching the display screen via a finger or stylus. In general, the touch screen can recognize the touch and position of the touch on the display screen, and the computing system can interpret the touch and thereafter perform an action based on the touch event.
Touch panels can include an array of touch sensors capable of detecting touch events (the touching of fingers or other objects upon a touch-sensitive surface). Future panels may be able to detect multiple touches (the touching of fingers or other objects upon a touch-sensitive surface at distinct locations at about the same time) and near touches (fingers or other objects within the near-field detection capabilities of their touch sensors), and identify and track their locations. Examples of multi-touch panels are described in Applicant's co-pending U.S. application Ser. No. 10/842,862 entitled “Multipoint Touchscreen,” filed on May 6, 2004 and published as U.S. Published Application No. 2006/0097991 on May 11, 2006, the contents of which are incorporated by reference herein.
Various materials, adhesives, and processing steps are required to make a touch screen stackup that can be functional, cost-effective, and space-efficient.
SUMMARY OF THE INVENTION
This relates to a multi-touch sensor panel that can include a glass subassembly that can have a plurality of column traces of substantially transparent conductive material formed on the back side, the glass subassembly also acting in some embodiments as a cover that can be touched on the front side. Row traces of the same or different substantially transparent conductive material can then be located near the column traces, with a layer of dielectric material that can be coupled between the column traces and the row traces. The row and column traces can be oriented to cross over each other at crossover locations separated by the dielectric material, wherein the crossover locations can form mutual capacitance sensors for detecting one or more touches on the front side of the glass subassembly.
Alternative touch screen sensor panel embodiments can be fabricated with (1) rows and columns on the back side of a cover glass, (2) columns on the back side of a cover glass and rows on the bottom side of a separate polyethylene terephthalate (PET) film, (3) columns and rows formed on opposite sides of a single substrate, (4) columns and rows formed on two separate PET films, and (5) columns on the back side of a cover glass and rows on the top side of a separate PET film.



BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a-1d illustrate various exemplary touch screen sensor panel stackups with rows and columns that can be formed on the back side of a cover glass according to one embodiment of this invention.
FIGS. 2a-2d illustrate various exemplary touch screen sensor panel stackups with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIGS. 3a-3c illustrate various exemplary touch screen sensor panel stackups with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIGS. 4a-4d illustrate various exemplary touch screen sensor panel stackups with rows and columns that can be formed on the back side of a cover glass according to one embodiment of this invention.
FIGS. 5a and 5b illustrate various exemplary touch screen sensor panel stackups with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIGS. 6a and 6b illustrate various exemplary touch screen sensor panel stackups with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIGS. 7a-7d illustrate various exemplary touch screen sensor panel stackups with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 8 illustrates an exemplary touch screen sensor panel stackup with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIG. 9 illustrates an exemplary touch screen sensor panel stackup with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 10 illustrates an exemplary touch screen sensor panel stackup with columns that can be formed on the back side of a cover glass and rows that can be formed on the top side of a separate glass substrate according to one embodiment of this invention.
FIGS. 11a-11c illustrate various exemplary touch screen sensor panel stackups with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 12 illustrates a side view of an exemplary flexible printed circuit (FPC) stackup according to one embodiment of this invention.
FIGS. 13a and 13b illustrate top views of an exemplary FPC design according to one embodiment of this invention.
FIG. 14 illustrates top views of exemplary FPC designs that can connect to the rows and columns of the sensor panel according to one embodiment of this invention.
FIG. 15 illustrates a side view of an exemplary flexible printed circuit (FPC) stackup according to one embodiment of this invention.
FIGS. 16a-16c illustrate top views of an exemplary FPC design according to one embodiment of this invention.
FIG. 17a illustrates an exemplary partially fabricated cover for a touch screen sensor panel according to one embodiment of this invention.
FIG. 17b illustrates an exemplary top PET film according to one embodiment of this invention.
FIG. 17c illustrates an exemplary touch screen sensor panel stackup with columns and rows that can be formed on two separate PET films according to one embodiment of this invention.
FIG. 18 illustrates an exemplary computing system that can be operable with the touchscreen stackups according to one embodiment of this invention.
FIG. 19a illustrates an exemplary mobile telephone that can include the touchscreen stackups and computing system according to embodiments of the invention.
FIG. 19b illustrates an exemplary digital audio/video player that can include the touchscreen stackups and computing system according to embodiments of the invention.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
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 invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the preferred embodiments of the present invention.
It should be understood that in all of the figures and descriptions that follow, the listed materials, properties and dimensions (listed in units of millimeters unless otherwise noted) are merely exemplary in nature and are not intended to limit the scope of the invention.
FIGS. 1a-1d illustrate various exemplary touchscreen sensor panel stackups with rows and columns that can be formed on the back side of a cover glass according to one embodiment of this invention.
FIG. 1a shows window 1116 that can be formed in 0.8 to 1.0 polycarbonate (PC) housing 118. Within window 116 can be a stack-up in which the row and column traces can be formed on the back side of a cover glass. Substantially transparent glass subassembly 100 can have a front or top side capable of sensing when the user touches the window above it, and a back side opposite the front side. Glass subassembly 100 can have a stackup of layers that can include, in order from top to bottom, substantially transparent anti-glare (AG) coating 113 (shown as a dashed line at the top of the subassembly) (or this can be anti-reflective (AR) coating, or just plain glass or plastic surface of the window), substantially transparent 0.7 borosilicate or aluminum silicate glass, black mask (in limited areas), substantially transparent conductive material such as patterned Indium Tin Oxide (ITO) (15 to 200 ohms per square max, with 0.3 lines and 0.030 spaces) formed as columns, a substantially transparent 0.025 dielectric layer (e.g. sol-gel TIO2) with vias, and another layer of substantially transparent conductive material such as patterned ITO (15 to 200 ohm max, with 0.3 lines and 0.030 spaces) formed as rows. The two layers of patterned substantially transparent conductive material can be of the same or different composition. The black mask (or a mask of any color) can be used to hide the electrical interconnect such as metal traces located in the border areas of the touchscreen. The dielectric layer can be used as a planarization layer to enable the one layer of patterned ITO to be formed on top of another. Note that these patterned ITO layers and the dielectric layer in between are symbolically illustrated in FIG. 1a as a dashed line representing patterning 102.
Substantially transparent PET subassembly 106 can be bonded to glass subassembly 100 using pressure sensitive adhesive (PSA) 108. One purpose of PET subassembly 106 can be to support a 0.188 continuous sheet of ITO (500 ohm max) that can be formed on the bottom of the PET film which can be used to shield the glass subassembly from LCD 110, and also to provide a low capacitive spacing between the shield layer of ITO and the rows and columns. Together, glass subassembly 100 through PET film subassembly 100, and any intervening layers, can form the touchscreen.
Flexible printed circuit (FPC) 104 can be bonded using anisotropic conductive film (ACF) (0.003 after bonding) to the back side of glass subassembly 100. Conductive tape 112 can be used to ground the ITO formed on the bottom of the PET subassembly 106. Substantially transparent PSA 114 of 0.125 thickness can be used to bond PET film subassembly 106 to the LCD module, which can include a 0.2 polarizer layer 115 and liquid crystals 117. The complete assembly can then be mounted into window 116 in housing 118. Note that when the complete assembly is mounted in housing 118, glass subassembly 100 can be either even with or slightly recessed (0.3 Z step) from the top of the window.
FIG. 1b is similar to FIG. 1a, except that PET film subassembly 106 is not fully laminated to LCD module 110. Instead, air gap 120 can be formed between them, and a ring of Poron 122 can be formed around the perimeter of the touchscreen. The air gap can allow for easier separation of the touchscreen from the LCD module in case repair, replacement or upgrading is needed. Anti-reflective (AR) coating can be applied to one or both surfaces adjacent to the air-gap to minimize reflections and associated contrast ratio degradation.
FIG. 1c is similar to FIG. 1b in that it includes air gap 120, but it can be mounted into an enclosure having overhanging bezel 124. This can be less expensive because bezel 124 can hide electrical interconnect formed in the border areas of the touchscreen, which can eliminate the need for blackmask. In addition, it can be less expensive because the housing can cover the edges of the touchglass, eliminating the need for grinding and polishing steps. Glass subassembly 132 can be identical to glass subassembly 100 in FIG. 1.
FIG. 1d is a hybrid of FIGS. 1a and 1c, wherein overhanging bezel 124 can allow the blackmask step to be eliminated, and full lamination can be used (see full layer of PSA 108). Note that full lamination can result in a mechanically stiffer and stronger stackup, but the benefit of having an air gap is that it can make the parts separable and replaceable.
FIGS. 2a-2d illustrate various exemplary touch screen sensor panel stackups with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIG. 2a shows window 216 that can be formed in 0.8 to 1.0 PC housing 218. Within window 216 can be a stack-up in which the column traces can be formed on the back side of a cover glass and row traces can be formed on the bottom side of a separate PET film. Substantially transparent glass subassembly 234 can have a stackup of layers that can include, in order from top to bottom, substantially transparent AG coating 213 (shown as a dashed line at the top of the subassembly), substantially transparent 0.7 borosilicate or aluminum silicate glass, black mask (in limited areas), and substantially transparent conductive material such as patterned ITO (15 to 200 ohm max, with 0.3 lines and 0.030 spaces) formed as columns. Note that the patterned ITO layer is symbolically illustrated in FIG. 2a as a dashed line representing patterning 250. Substantially transparent PET subassembly 236 of thickness 0.188 can be bonded to glass subassembly 234 using PSA 208. One purpose of PET subassembly 236 can be to support a substantially transparent layer of conductive material such as patterned ITO (75 to 500 ohm max, with 5.0 lines and 0.050 spaces) formed as rows, and also to provide a low capacitive layer between the rows and columns. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Together, glass subassembly 234 through PET film subassembly 236, and any intervening layers, can form the touchscreen.
FPC 204 can be bonded using ACF (0.003 after bonding) to the back side of glass subassembly 234. FPC 226 can be also bonded using ACF to the rows that can be formed on the bottom of PET subassembly 236. Substantially transparent PSA 214 of 0.125 thickness can be used to bond PET film subassembly 236 to LCD module 210, which can include a 0.2 polarizer layer 215 and liquid crystals 217. The complete assembly can then be mounted into window 216 in housing 218. Note that when the complete assembly is mounted in housing 218, glass subassembly 234 can be either even with or slightly recessed (0.3 Z step) from the top of the window.
FIG. 2b is similar to FIG. 2a, except that PET film subassembly 236 is not fully laminated to LCD module 210. Instead, air gap 220 can be formed between them, and a ring of Poron 222 can be formed around the perimeter of the touchscreen.
FIG. 2c is similar to FIG. 2b in that it includes air gap 220, but it can be mounted into an enclosure having overhanging bezel 224.
FIG. 2d is a hybrid of FIGS. 2a and 2c, wherein overhanging bezel 224 can allow the blackmask step to be eliminated, and full lamination can be used (see full layer of PSA 208).
FIGS. 3a and 3b illustrate various exemplary touch screen sensor panel stackups with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 3a shows an approximately 0.9 substantially transparent PC (or glass) housing 318. Bonded to housing 318 using 0.100 substantially transparent PSA 308 can be a stack-up in which the column traces and row traces can be formed on opposite sides of a single substrate. Substantially transparent glass subassembly 338 can have a stackup of layers that can include, in order from top to bottom, for example, substantially transparent conductive material such as patterned ITO (15 to 200 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, substantially transparent 0.7 borosilicate or aluminum silicate or chemically strengthened soda lime glass, and substantially transparent conductive material such as patterned ITO (75 to 200 ohm max, with 5.0 lines and 0.050 spaces) formed as rows. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Note that the patterned ITO layers are symbolically illustrated in FIG. 3a as dashed lines representing patterning 319 and 350.
FPC 330 can be bonded using ACF (0.003 after bonding) to the rows on the back side of glass subassembly 338, and also another FPC (not shown in FIG. 3a) can be bonded to the columns which are on the front or top side of the glass. Clear PSA 314 of 0.100 thickness can be used to bond glass subassembly 338 to LCD module 310, which can include polarizer layer 315 and liquid crystals 317.
FIG. 3b is similar to FIG. 3a, except that glass subassembly 338 is not fully laminated to LCD module 310. Instead, air gap 320 can be formed between them, and a ring of Poron 322 can be formed around the perimeter of glass subassembly 338. AR films or coatings can be applied to the back of the touch glass, and the front of the polarizer, to minimize optical losses.
FIG. 3c is similar to FIG. 3a, except that passivation layers 301 are formed between patterning 319 and PSA 309, and between patterning 350 and PSA 314. Passiviation layers 301 can be formed from silicon oxide, and can serve to prevent acid in the PSA from attacking the patterned ITO. Passivation layers 301 can also physically protect the ITO and metal layers from other corrosive agents, such as sweat from an assembly operator during the manufacturing process, and can physically protect the ITO and metal layers from scratches during assembly. It should be understood that although the use of passivation layers between ITO patterning and the PSA is only shown in FIG. 3c, a passivation layer can be formed between the ITO or metal and the PSA in any of the embodiments described and shown herein.
FIGS. 4a-4d illustrate various exemplary touch screen sensor panel stackups with rows and columns that can be formed on the back side of a cover glass according to one embodiment of this invention.
FIG. 4a shows window 416 that can be formed in 0.8 to 1.0 substantially transparent PC housing 418. Within window 416 can be a stack-up in which the column and row traces can be formed on the back side of a cover glass. Substantially transparent glass subassembly 442 can have a stackup of layers that can include, in order from top to bottom, for example, substantially transparent AG coating 413 (shown as a dashed line at the top of the subassembly), substantially transparent 0.7 borosilicate or aluminum silicate glass, black mask (in limited areas), substantially transparent conductive material such as patterned ITO (15 to 200 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, 0.025 mm substantially transparent dielectric (sol-gel TIO2) with vias, patterned metal (0.025 ohm max, 0.030 lines and 0.030 spaces), and a 0.188 layer of substantially transparent conductive material such as patterned ITO (75 to 200 ohm max, with 0.3 lines and 0.030 spaces) formed as rows. The patterned metal can be formed in the border areas of the touchscreen to connect to the rows and/or columns and route them to an edge of the touchscreen. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Note that the patterned ITO layers, dielectric and metal are symbolically illustrated in FIG. 4a as a dashed line representing patterning 444. Substantially transparent PET subassembly 406 can be bonded to glass subassembly 442 using substantially transparent PSA 408. One purpose of PET subassembly 406 can be to support a 0.188 continuous sheet of ITO (500 ohm). Together, glass subassembly 442 through PET film subassembly 406, and any intervening layers, can form the touchscreen.
FPC 404 can be bonded using ACF (0.003 after bonding) to the back side of glass subassembly 442. Conductive tape 412 can also be bonded using ACF to PET subassembly 406 to ground the continuous sheet of ITO. Substantially transparent PSA 414 of 0.125 thickness can be used to bond PET film subassembly 406 to LCD module 410, which can include a 0.2 polarizer layer 415 and liquid crystals 417. The complete assembly can then be mounted into window 416 in housing 418. Note that when the complete assembly is mounted in housing 418, glass subassembly 442 can be either even with or slightly recessed (0.3 Z step) from the top of the window.
Chip on glass 446 can be connected to metal border traces, rows and column traces on glass subassembly 442. Chip on glass 446 can be supported in a hole or cutout on PET film subassembly 406, and can contain one or more components of a sensor panel subsystem, including one or more processors, drivers, analog channels, and the like. The polarizer may also have a hole or cutout to allow the presence of the chip on glass. Chip on glass 446 can enable only a very small flex connector to be attached to the touchscreen to communicate with the system processor, because now most of the circuitry can be contained on the touchscreen.
FIG. 4b is similar to FIG. 4a, except that PET film subassembly 406 is not fully laminated to LCD module 410. Instead, air gap 420 can be formed between them, and a ring of Poron 422 can be formed around the perimeter of the touchscreen. AR coating can also be used to minimize losses.
FIG. 4c is similar to FIG. 4b in that it includes air gap 420, but it is mounted into clear PC housing 424 having overhanging bezel. A sealing ring of Poron 422 can be formed between the bezel and glass subassembly 442.
FIG. 4d is a hybrid of FIGS. 4a and 4c, wherein an overhanging bezel can allow the blackmask on glass subassembly 442 to be eliminated, and full lamination can be used (see full layer of PSA 414).
FIGS. 5a and 5b illustrate various exemplary touch screen sensor panel stackups with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIG. 5a shows window 516 that can be formed in 0.8 to 1.0 PC housing 518. Within window 516 can be a stack-up in which the column traces can be formed on the back side of a cover glass and row traces can be formed on the bottom side of a separate PET film. Substantially transparent glass subassembly 534 can have a stackup of layers that can include, in order from top to bottom, substantially transparent AG coating 513 (shown as a dashed line at the top of the subassembly), substantially transparent 0.7 borosilicate or aluminum silicate glass, black mask (in limited areas), and substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) formed as columns. Note that the patterned ITO layer is symbolically illustrated in FIG. 5a as a dashed line representing patterning 550. Substantially transparent PET subassembly 536 can be bonded to glass subassembly 534 using substantially transparent PSA 508. One purpose of PET subassembly 536 can be to support a 0.188 layer of substantially transparent conductive material such as patterned ITO (150 ohm max, with 5.0 lines and 0.050 spaces) formed as rows, and also to provide a low capacitive layer between the rows and columns. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Chip on glass 546 can be connected to column traces on glass subassembly 534, and to row traces on PET film subassembly 536. Chip on glass 546 can be supported in a hole on PET film subassembly 536, and can contain one or more components of a sensor panel subsystem, including one or more processors, drivers, analog channels, and the like. Together, glass subassembly 534 through PET film subassembly 536, chip on glass 546 and any intervening layers, can form the touchscreen.
FPC 504 can be bonded using 0.125 thick (max) ACF to the back side of glass subassembly 534. FPC can also be bonded using ACF to the rows formed on the bottom of PET subassembly 536. Substantially transparent PSA 514 of 0.125 thickness can be used to bond PET film subassembly 536 to LCD module 510, which can include a 0.2 polarizer layer 515 and liquid crystals 517. The complete assembly can then be mounted into window 516 in housing 518. Note that when the complete assembly is mounted in housing 518, glass subassembly 534 can be either even with or slightly recessed (0.3 Z step) from the top of the window.
FIG. 5b is similar to FIG. 5a, except that PET film subassembly 536 is not fully laminated to LCD module 510. Instead, air gap 520 can be formed between them, and a ring of Poron 522 can be formed around the perimeter of the touchscreen.
FIGS. 6a and 6b illustrate various exemplary touch screen sensor panel stackups with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIG. 6a shows PC housing 624 having an overhanging bezel. A sealing ring of Poron 622 can be formed between the bezel and substantially transparent glass subassembly 652. Glass subassembly 652 can be part of a stack-up in which the column traces can be formed on the back side of the glass subassembly and row traces can be formed on the bottom side of a separate PET film. Glass subassembly 652 has a stackup of layers that can include, in order from top to bottom, substantially transparent AG coating 613 (shown as a dashed line at the top of the subassembly), substantially transparent 0.7 borosilicate or aluminum silicate glass, black mask (in limited areas), substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, and patterned metal (0.025 ohm max, with 0.030 lines and 0.030 spaces). Note that the patterned ITO and metal layer is symbolically illustrated in FIG. 6a as a dashed line representing patterning 654. Substantially transparent PET subassembly 636 can be bonded to glass subassembly 652 using substantially transparent PSA 608. One purpose of PET subassembly 636 can be to support a 0.188 layer of substantially transparent conductive material such as patterned ITO (150 ohm max, with 5.0 lines and 0.050 spaces) formed as rows, and also to provide a low capacitive layer between the rows and columns. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Chip on glass 646 can be connected to column traces on glass subassembly 652, and to row traces on PET film subassembly 636. Chip on glass 646 can be supported in a hole on PET film subassembly 636, and can contain one or more components of a sensor panel subsystem, including one or more processors, drivers, analog channels, and the like. Together, glass subassembly 652 through PET film subassembly 636, chip on glass 646 and any intervening layers, can form the touchscreen.
FPC 604 can be bonded using 0.125 thick (max) ACF to the back side of glass subassembly 652. FPC 604 can also be bonded using ACF to the rows formed on the bottom of PET subassembly 636. Air gap 620 can be formed between PET film subassembly 636 and LCD module 610, which can include a 0.2 polarizer layer 615 and liquid crystals 617, and a ring of Poron 622 can be formed around the perimeter of the touchscreen.
FIG. 6b is similar to FIG. 6a, except that PET film subassembly 636 can be fully laminated to LCD module 610 using PSA 614.
FIGS. 7a-7d illustrate various exemplary touch screen sensor panel stackups with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 7a shows 0.9 substantially transparent PC (or glass) housing 718. Bonded to housing 718 using 0.100 substantially transparent PSA 708 can be a stack-up in which the column traces and row traces can be formed on opposite sides of a single substrate. Substantially transparent glass subassembly 756 can have a stackup of layers that can include, in order from top to bottom, substantially transparent conductive material such as patterned ITO (15 to 200 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, substantially transparent 0.5 borosilicate or aluminum silicate glass, and substantially transparent conductive material such as patterned ITO (75 ohm max, with 0.5 lines and 0.050 spaces) formed as rows. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Note that the patterned ITO layers are symbolically illustrated in FIG. 7a as dashed lines representing patterning 719 and 750.
FPC 730 and 704 can be bonded using 0.125 thick (max) ACF to the columns and rows on either side of glass subassembly 756. Substantially transparent PSA 714 of 0.100 thickness can be used to bond glass subassembly 756 to LCD module 710, which can include polarizer layer 715 and liquid crystals 717.
FIG. 7b is similar to FIG. 7a, except that glass subassembly 756 is not fully laminated to LCD module 710. Instead, air gap 720 can be formed between them, and a ring of Poron 722 can be formed around the perimeter of glass subassembly 756.
FIG. 7c is similar to FIG. 7a, but additionally shows an implementation of wings 758 on FPC 760 (see thumbnail at lower left corner). Each FPC 760 can be generally long and slender to provide maximum panel utilization. In the thumbnail of FIG. 7c, the upper FPC 704 can get folded back, as can the lower FPC 730, and they can be connected together behind the panel.
FIG. 7d is similar to FIG. 7b, but additionally shows an implementation of wings 758 on FPC 760 (see thumbnail at lower left corner). Each FPC 760 can be generally long and slender to provide maximum panel utilization. In the thumbnail of FIG. 7c, the upper FPC 704 can get folded back, as can the lower FPC 730, and they can be connected together behind the panel.
FIG. 8 illustrates an exemplary touch screen sensor panel stackup with columns that can be formed on the back side of a cover glass and rows that can be formed on the bottom side of a separate PET film according to one embodiment of this invention.
FIG. 8 shows window 816 formed in 0.9 PC housing 818. Within window 816 can be a stack-up in which the column traces can be formed on the back side of a cover glass and row traces can be formed on the bottom side of a separate PET film. Substantially transparent glass subassembly 862 can have a stackup of layers that can include, in order from top to bottom, for example, substantially transparent AG coating 813 (shown as a dashed line at the top of the subassembly), substantially transparent 0.7 borosilicate or aluminum silicate glass, black mask (in limited areas), and substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) formed as columns. Note that the patterned ITO layer is symbolically illustrated in FIG. 8 as a dashed line representing patterning 864. Substantially transparent PET subassembly 868 of thickness 0.188 can be bonded to glass subassembly 862 using PSA 808. One purpose of PET subassembly 868 can be to support a layer of substantially transparent conductive material such as patterned ITO (75 ohm max, with 5.0 lines and 0.050 spaces) that can be formed as rows, and also to provide a low capacitive layer between the rows and columns. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Together, glass subassembly 862 through PET film subassembly 868, and any intervening layers, can form the touchscreen.
FPC 804 can be bonded using 0.125 thick (max) ACF to the back side of glass subassembly 862. FPC 826 can also be bonded using ACF to the rows that can be formed on the bottom of PET subassembly 868. Substantially transparent PSA 814 of 0.125 thickness can be used to bond PET film subassembly 868 to LCD module 810, which can include a 0.2 polarizer layer 815 and liquid crystals 817. The complete assembly can then be mounted into window 816 in housing 818. Note that when the complete assembly is mounted in housing 818, glass subassembly 862 can be either even with or slightly recessed (0.3 Z step) from the top of the window. FIG. 8 also shows additional detail in the thumbnails (at the bottom left of FIG. 8) on how the FPCs 860 can be connected to the sensor panel.
FIG. 9 illustrates an exemplary touch screen sensor panel stackup with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 9 shows window 916 that can be formed in 0.9 PC housing 918. Within window 916 can be a stack-up in which the column traces and row traces can be formed on opposite sides of a single substrate. Substantially transparent glass subassembly 972 can have a stackup of layers that can include, in order from top to bottom, substantially transparent AG coating, substantially transparent 0.5 borosilicate or aluminum silicate glass, and black mask (in limited areas). Substantially transparent glass subassembly 976 can have a stackup of layers that can include, in order from top to bottom, substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, substantially transparent 0.5 borosilicate or aluminum silicate glass, and substantially transparent conductive material such as patterned ITO (75 ohm max, with 0.5 lines and 0.050 spaces) formed as rows. The two layers of patterned substantially transparent conductive material can be of the same or different composition. PSA 908 can be used to bond glass subassemblies 972 and 976 together. Note that the patterned ITO layers are symbolically illustrated in FIG. 9 as dashed lines representing patterning 978 and 980.
FPC can be bonded using 0.125 thick (max) ACF to the columns and rows on either side of glass subassembly 976. Substantially transparent PSA 914 of 0.125 thickness can be used to bond glass subassembly 976 to LCD module 910, which can include polarizer layer 915 and liquid crystals 917.
FIG. 10 illustrates an exemplary touch screen sensor panel stackup with columns that can be formed on the back side of a cover glass and rows that can be formed on the top side of a separate glass substrate according to one embodiment of this invention.
FIG. 10 shows window 1016 that can be formed in 0.9 PC housing 1018. Within window 1016 can be a stack-up in which the column traces can be formed on the back side of a cover glass and row traces can be formed on the top side of a separate PET film. Substantially transparent glass subassembly 1082 can have a stackup of layers that can include, in order from top to bottom, substantially transparent AG coating 1013 (shown as a dashed line at the top of the subassembly), substantially transparent 0.5 borosilicate or aluminum silicate glass, black mask (in limited areas), and substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) that can be formed as columns. Substantially transparent glass subassembly 1084 can have a stackup of layers that can include, in order from top to bottom, substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, substantially transparent 0.5 borosilicate or aluminum silicate glass, and a continuous sheet of substantially transparent ITO (500 ohm max). The two layers of patterned substantially transparent conductive material can be of the same or different composition. Glass subassemblies 1082 and 1084 can be bonded together with substantially transparent PSA 1008. Note that the patterned ITO layers are symbolically illustrated in FIG. 10 as dashed lines representing patterning 1064 and 1086. Together, glass subassembly 1082 through glass subassembly 1084, and any intervening layers, can form the touchscreen.
FPCs can be bonded using 0.125 thick (max) ACF to the back side of glass subassembly 1082 and the top side of glass subassembly 1084. Substantially transparent PSA 1014 of 0.125 thickness can be used to bond glass subassembly 1084 to LCD module 1010, which can include a 0.2 polarizer layer 1015 and liquid crystals 1017. The complete assembly can then be mounted into window 1016 in housing 1018. Note that when the complete assembly is mounted in housing 1018, glass subassembly 1082 can be either even with or slightly recessed (0.3 Z step) from the top of the window.
FIGS. 11a-11c illustrate various exemplary touch screen sensor panel stackups with columns and rows that can be formed on opposite sides of a single substrate according to one embodiment of this invention.
FIG. 11a shows an approximately 0.9 substantially transparent PC housing 1118. Substantially transparent hard film or glass 1188 and blackmask 1190 (in limited areas) can be inserted into the mold when the housing 1118 is being injection-molded to provide a hard surface and hiding properties (where the blackmask is placed). Bonded to housing 1118 using 0.100 substantially transparent PSA 1108 can be a stack-up in which the column traces and row traces can be formed on opposite sides of a single substrate. Substantially transparent glass subassembly 1176 can have a stackup of layers that can include, in order from top to bottom, substantially transparent conductive material such as patterned ITO (15 ohm max, with 0.3 lines and 0.030 spaces) formed as columns, substantially transparent 0.5 borosilicate or aluminum silicate glass, and substantially transparent conductive material such as patterned ITO (75 ohm max, with 5.0 lines and 0.050 spaces) formed as rows. The two layers of patterned substantially transparent conductive material can be of the same or different composition. Note that the patterned ITO layers are symbolically illustrated in FIG. 11a as dashed lines representing patterning 1178 and 1180.
FPCs can be bonded using 0.125 thick (max) ACF to the columns and rows on either side of glass subassembly 1176. Substantially transparent PSA 1114 of 0.100 thickness can be used to bond glass subassembly 1176 to LCD module 1110, which can include polarizer layer 1115 and liquid crystals 1117.
FIG. 11b is similar to FIG. 11a, except that hard film or glass and blackmask are not formed in the housing 1118.
FIG. 11c is similar to FIG. 1b, except that glass subassembly 1176 is not fully laminated to LCD module 1110. Instead, air gap 1120 can be formed between them, and a ring of Poron 1122 can be formed around the perimeter of glass subassembly 1176.
FIG. 12 illustrates a side view of an exemplary FPC stackup according to one embodiment of this invention. FIG. 12 shows an FPC stackup for the thin wings or strips on the FPCs that can include release liner 1210, 0.025 ACF and PSA 1208, 0.012 via plating 1206, 0.018 copper 1204, 0.012 adhesive for the copper 1202, 0.025 polyamide substrate 1212, 0.012 adhesive for the copper 1202, 0.018 copper 1204, 0.012 via plating 1206, 0.025 ACF and PSA 1208, and release liner 1210.
FIGS. 13a and 13b illustrate top views of an exemplary FPC design according to one embodiment of this invention. FIG. 13a shows an ACF-side view of the FPC that connects to the drive rows, including ACF pads 1306 at which the FPC can be bonded to the glass substrate using ACF 1302 that can be 0.5 wide and 0.025 thick. However, traces 1304 having 0.100 widths and 0.100 spacing can be bonded to the glass substrate using insulating PSA 1308 that can be 1.3 wide and 0.025 thick. FIG. 13b shows the non-ACF-side top view of the FPC traces that can connect to the drive rows, including traces 1304 that can be covered by insulating PSA 1308, 0.018 thick.
FIG. 14 illustrates top views of exemplary FPC designs for connecting to the rows and columns of the sensor panel according to one embodiment of this invention. FIG. 14 shows detail of drive FPC 1402 and sense FPC 1400, including drive flex tail 1404 and zero insertion force (ZIF) connector 1406.
FIG. 15 illustrates a side view of an exemplary FPC stackup according to one embodiment of this invention. FIG. 15 shows FPC drive layer stackup 1500 for the thin wings or strips on the FPCs that can include 0.012 coverlay 1514, 0.012 adhesive 1502, 0.025 ACP 1508, 0.012 via plating 1506, 0.018 copper 1504, 0.012 adhesive for the copper 1502, 0.025 polyamide substrate 1512, 0.012 adhesive for the copper 1502, 0.018 copper 1504, 0.012 via plating 1506, 0.012 adhesive 1502, and 0.012 coverlay 1514.
FIGS. 16a-16c illustrate top views of an exemplary FPC design according to one embodiment of this invention. FIG. 16a shows a non-ACF-side view 1600 of the FPC that can connect to the drive rows, including ACF pads 1606 having ACP of 0.025 thickness at which the FPC can be bonded to the glass substrate. However, traces 1610 having 0.075 widths and 0.075 spacing can be bonded to the glass substrate using insulating PSA 1612 that can be 0.025 thick. FIG. 16b shows the ACF-side top view 1618 of the FPC traces that can connect to the drive rows, including traces 1604 that can have 0.075 widths and 0.075 spacing, covered by insulating PSA 1608, 0.025 thick. FIG. 16c shows ITO pattern registration 1620 with visual alignment mark 1614 separating ITO row patterns 1616.
FIG. 17a illustrates an exemplary partially fabricated cover for a touch screen sensor panel according to one embodiment of this invention. FIG. 17a shows plastic top housing 1700 (e.g., injection molded polycarbonate or acrylic of 0.80 thickness) for an individual part with a corner, with hard coat/anti-glare coating 1704 that can be formed on top and black mask 1706 that can be selectively applied to the inside of housing 1702.
FIG. 17b illustrates an exemplary top PET film according to one embodiment of this invention. First, ITO 1712 (e.g., having a resistivity of 40 to 500 ohms per square) can be sputtered onto PET film 1710 (e.g. PET or polymer having a dielectric constant of 3 to 4 and a thickness of about 25 to 75 microns) and patterned (e.g. into 100 micron lines and spaces) using standard photolithography and etching techniques, or laser oblation. Next, a layer of metal (silkscreened silver ink) 1714 (e.g., silver ink having a resistivity of 1 ohm per square max) can be applied over the ITO and patterned (e.g. into 200 micron lines and spaces). A protective sheet of black carbon 1716 (e.g. having 0.25 lines and spaces) can then be printed over the silver ink traces to serve as a protective coating for connector contacts. A tail coverlay 1718 (e.g., PET having a thickness of 25 to 75 microns) can then be formed over the silver ink traces for protection. A sheet of PSA 1720 (e.g., having a thickness of 25 microns) and a sacrificial liner can then be formed over the PET film and ITO. A bottom PET film can be formed using the same process.
FIG. 17c illustrates an exemplary touch screen sensor panel stackup with columns and rows that can be formed on two separate top and bottom PET films 1708 and 1724 according to one embodiment of this invention. Optically clear adhesive 1726 can be used to bond the top and bottom PET films between a cover 1700 and an LCD module that can include LCD polarizer 1728, LCD top glass 1730, and LCD bottom glass 1732.
FIG. 18 illustrates exemplary computing system 1800 operable with the touchscreen stackups described above according to embodiments of this invention. Touchscreen 1842, which can include sensor panel 1824 and display device 1840, can be connected to other components in computing system 1800 through connectors integrally formed on the sensor panel, or using flex circuits. Computing system 1800 can include one or more panel processors 1802 and peripherals 1804, and panel subsystem 1806. The one or more processors 1802 can include, for example, ARM968 processors or other processors with similar functionality and capabilities. However, in other embodiments, the panel processor functionality can be implemented instead by dedicated logic such as a state machine. Peripherals 1804 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 1806 can include, but is not limited to, one or more analog channels 1808, channel scan logic 1810 and driver logic 1814. Channel scan logic 1810 can access RAM 1812, autonomously read data from the analog channels and provide control for the analog channels. This control can include multiplexing columns of multi-touch panel 1824 to analog channels 1808. In addition, channel scan logic 1810 can control the driver logic and stimulation signals being selectively applied to rows of multi-touch panel 1824. In some embodiments, panel subsystem 1806, panel processor 1802 and peripherals 1804 can be integrated into a single application specific integrated circuit (ASIC).
Driver logic 1814 can provide multiple panel subsystem outputs 1816 and can present a proprietary interface that drives high voltage driver 1818. High voltage driver 1818 can provide level shifting from a low voltage level (e.g. complementary metal oxide semiconductor (CMOS) levels) to a higher voltage level, providing a better signal-to-noise (S/N) ratio for noise reduction purposes. Panel subsystem outputs 1816 can be sent to decoder 1820 and level shifter/driver 1838, which can selectively connect one or more high voltage driver outputs to one or more panel row inputs 1822 through a proprietary interface and enable the use of fewer high voltage driver circuits in the high voltage driver 1818. Each panel row input 1822 can drive one or more rows in a multi-touch panel 1824. In some embodiments, high voltage driver 1818 and decoder 1820 can be integrated into a single ASIC. However, in other embodiments high voltage driver 1818 and decoder 1820 can be integrated into driver logic 1814, and in still other embodiments high voltage driver 1818 and decoder 1820 can be eliminated entirely.
Computing system 1800 can also include host processor 1828 for receiving outputs from panel processor 1802 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 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'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 1828 can also perform additional functions that may not be related to panel processing, and can be coupled to program storage 1832 and display device 1840 such as an LCD for providing a user interface (UI) to a user of the device.
As mentioned above, multi-touch panel 1824 can in some embodiments include a capacitive sensing medium that can have a plurality of row traces or driving lines and a plurality of column traces or sensing lines separated by a dielectric. In some embodiments, the dielectric material can be transparent, such as PET or glass. The row and column traces can be formed from a transparent conductive medium such as ITO or antimony tin oxide (ATO), although other non-transparent materials such as copper can also be used. In some embodiments, the row and column traces can be perpendicular to each other, although in other embodiments other non-orthogonal orientations are possible. For example, in a polar coordinate system, the sensing lines can be concentric circles and the driving lines can be radially extending lines (or vice versa). It should be understood, therefore, that the terms “row” and “column,” “first dimension” and “second dimension,” or “first axis” and “second axis” as may be used herein are intended to encompass not only orthogonal grids, but the intersecting traces of other geometric configurations having first and second dimensions (e.g. the concentric and radial lines of a polar-coordinate arrangement).
At the “intersections” of the traces, where the traces can pass above and below each other (but do not make direct electrical contact with each other), the traces can essentially form two electrodes. Each intersection of row and column traces can represent a capacitive sensing node and can be viewed as picture element (pixel) 1826, which can be particularly useful when multi-touch panel 1824 is viewed as capturing an “image” of touch. (In other words, after panel subsystem 1806 has determined whether a touch event has been detected at each touch sensor in multi-touch panel 1824, 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).) When the two electrodes are at different potentials, each pixel can have an inherent self or mutual capacitance formed between the row and column electrodes of the pixel. If an AC signal is applied to one of the electrodes, such as by exciting the row electrode with an AC voltage at a particular frequency, an electric field and an AC or signal capacitance can be formed between the electrodes, referred to as Csig. The presence of a finger or other object near or on multi-touch panel 1824 can be detected by measuring changes to Csig. The columns of multi-touch panel 1824 can drive one or more analog channels 1808 in panel subsystem 1806. In some embodiments, each column can be coupled to one dedicated analog channel 1808. However, in other embodiments, the columns can be couplable via an analog switch to a fewer number of analog channels 1808.
The touchscreen stackups described above can be advantageously used in the system of FIG. 18 to provide a space-efficient touch sensor panel and UI.
FIG. 19a illustrates exemplary mobile telephone 1936 that can include the touchscreen stackups and computing system described above according to embodiments of the invention. PSA 1934 can be used to bond sensor panel 1924 to display device (e.g. LCD module) 1930. FIG. 19b illustrates exemplary digital audio/video player 1940 that can include the touchscreen stackups and computing system described above according to embodiments of the invention. The mobile telephone and digital audio/video player of FIGS. 19a and 19b can advantageously benefit from the touchscreen stackups described above because the touchscreen stackups can allow these devices to be smaller and less expensive, which are important consumer factors that can have a significant effect on consumer desirability and commercial success.
Although the present invention has been fully described in connection with embodiments thereof 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 present invention as defined by the appended claims.

## Claims

1. A multi-touch sensor panel, comprising:
a transparent cover having a front side capable of being touched and a back side opposite the front side;
a subassembly including:
a substrate having a front surface adhered to the back side of the cover and a back surface, opposite the front surface for adhering to a liquid crystal display;
a plurality of first traces of a first substantially transparent conductive material formed by patterning on the front surface of the substrate; and
a plurality of second traces of a second substantially transparent material formed by patterning on the back surface of the substrate; and
wherein the substrate forms a dielectric material between the plurality of first traces and the plurality of second traces; and
wherein the plurality of first and the plurality of second traces are oriented to cross over each other at crossover locations separated by the dielectric material, the crossover locations forming mutual capacitance sensors for detecting one or more touches on the front side of the transparent cover;
wherein an adhesive, distinct from the substrate, is used to adhere the subassembly to the back side of the transparent cover and to adhere at least a portion of the subassembly to the liquid crystal display; and
wherein a passivation layer is disposed between the adhesive and the plurality of first traces and between the adhesive and the plurality of second traces.

2. The multi-touch sensor panel of claim 1 wherein the adhesive comprises a pressure sensitive adhesive and the passivation layer prevents acid in the pressure sensitive adhesive from damaging the plurality of first traces and the plurality of second traces.

3. The multi-touch sensor panel of claim 1, wherein the first and second substantially transparent conductive materials are the same.

4. The multi-touch sensor panel of claim 1, further comprising a flexible printed circuit (FPC) coupled to the plurality of second traces on the back side of the substrate.

5. The multi-touch sensor panel of claim 4, further comprising another flexible printed circuit coupled to the plurality of first traces on the front side of the substrate.

6. The multi-touch sensor panel of claim 1,
the panel further comprising a flexible printed circuit (FPC) coupled to at least one of the plurality of first or second traces, and
wherein the adhesive is a pressure sensitive adhesive and adheres the portion of the glass subassembly to a polarizer of the liquid crystal display.

7. The multi-touch sensor panel of claim 6, wherein flexible printed circuit board is coupled to the plurality of second traces and an anisotropic conductive film is used to bond the flexible printed circuit to at least the back side of glass subassembly.

8. A method for forming a multi-touch sensor panel comprising:
providing a transparent cover having a front side capable of being touched and a back side opposite the front side;
forming a plurality of first traces of a first substantially transparent conductive material by patterning the plurality of first traces on a front surface of a substrate;
forming a plurality of second traces of a second substantially transparent material by patterning the plurality of second traces on a back surface of the substrate, opposite the front surface;
orienting the plurality of first traces and the plurality of second traces to cross over each other at crossover locations separated by the substrate serving as a dielectric material, the crossover locations forming mutual capacitance sensors for detecting one or more touches on the front side of the subassembly; and
disposing a first passivation layer over the plurality of first traces on a front surface of the substrate;
disposing a second passivation layer over the plurality of second traces on a back surface of the substrate;
disposing an adhesive over the first and second passivation layers, the adhesive begin distinct from the substrate;
adhering the transparent cover to the adhesive disposed on the first passivation layer; and
adhering a display to the adhesive on the second passivation layer.