Touch screen stack-up processing
A multi-touch sensor panel is disclosed that can be produced by forming a plurality of first traces of substantially transparent conductive material on a first substrate, forming a plurality of second traces of the substantially transparent material, and creating a fluid-tight gap between the plurality of first traces and the plurality of second traces. The fluid-tight gap can then be filled with a fluid having substantially no bubbles and an optical index similar to the optical index of the first and second traces to make the gap and the first and second traces substantially transparent. The second and first traces can be oriented to cross over each other at crossover locations separated by the fluid, the crossover locations forming mutual capacitance sensors for detecting touches.
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The present invention claims the benefit under 35 USC 119(e) of U.S. provisional patent application Ser. No. 60/878,797 filed Jan. 5, 2007, the contents of which are incorporated by reference herein.
FIELD OF THE INVENTIONThis relates to touch screens, and more particularly, to methods and processes for forming the stack-up of materials comprising the touch screens.
BACKGROUND OF THE INVENTIONMany 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 can cover 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 Applicants 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 is functional, cost-effective, and space-efficient.
SUMMARY OF THE INVENTIONA multi-touch sensor panel can be produced by first forming a plurality of first traces of substantially transparent conductive material on a first substrate, forming a plurality of second traces of the substantially transparent material, and creating a fluid-tight gap between the plurality of first traces and the plurality of second traces. The fluid-tight gap can then be filled with a fluid having substantially no bubbles and an optical index similar to the optical index of the first and second traces to make the gap and the first and second traces substantially transparent. The second and first traces can be oriented to cross over each other at crossover locations separated by the fluid, the crossover locations forming mutual capacitance sensors for detecting touches.
In particular, a touch screen can be formed by first forming column traces on the back of a cover glass, forming row traces on the top of a substrate, and laminating the cover glass and substrate together with spacers in between, forming a fluid-tight gap. The fluid-tight gap can be filled with fluid having optical properties similar to the row and column traces. Integrated circuits (ICs) and flexible printed circuits (FPCs) can be bonded to the cover glass and encapsulated. The cover glass and substrate can further be bonded to an LCD module. Alternatively, both the column and row traces can be formed on the back side of the cover glass, separated by an insulator with dielectric properties.
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.
Because the use of PSA to fully laminate the exemplary first upper and lower layer subassemblies together can cause bubbles to form in the PSA, thereby reducing the clarity of the touch sensor panel, in embodiments of the invention fluid 130 can be used in some areas instead of full lamination for the purpose of providing optical index matching with few or no bubbles.
The first exemplary upper layer subassembly and the second exemplary lower layer subassembly can then be bonded together, and scribed and cut to remove excess material. An IC and/or FPC can then be bonded to the first exemplary upper layer subassembly, encapsulated, scribed and cut again to remove further excess material, and edge finished to form an exemplary second touch sensor panel assembly. The exemplary second touch sensor panel assembly can then be laminated to an LCD module. All of these steps can be performed as described above with regard to the exemplary first touchscreen.
It should be noted that the exemplary upper layer subassemblies of
Bottom ITO layer 562 having a resistivity of 500 ohms per square can then be applied to the bottom of top glass 500, and then covered by temporary protective film 564. ITO 562 can act a shield for the sensing columns. Note that the exemplary third upper layer subassembly of
A number of different computing systems can be operable with the touchscreen stackups described above according to embodiments of this invention. A touchscreen, which can include a sensor panel and a display device (e.g. an LCD module), can be connected to other components in the computing system through connectors integrally formed on the sensor panel, or using flex circuits. The computing system can include one or more panel processors and peripherals, and a panel subsystem. The one or more processors 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 can include, but are not limited to, random access memory (RAM) or other types of memory or storage, watchdog timers and the like.
The panel subsystem can include, but is not limited to, one or more analog channels, channel scan logic and driver logic. The channel scan logic can access RAM, autonomously read data from the analog channels and provide control for the analog channels. This control can include multiplexing columns of the multi-touch panel to analog channels. In addition, channel scan logic can control the driver logic and stimulation signals being selectively applied to rows of the multi-touch panel. In some embodiments, the panel subsystem, panel processor and peripherals can be integrated into a single application specific integrated circuit (ASIC).
Driver logic can provide multiple panel subsystem outputs and can present a proprietary interface that drives a high voltage driver. The high voltage driver can provide level shifting from a low voltage level (e.g. complementary metal oxide semiconductor (CMOS) levels) to a higher voltage level, which can provide a better signal-to-noise (S/N) ratio for noise reduction purposes. Panel subsystem outputs can be sent to a decoder and a level shifter/driver, which can selectively connect one or more high voltage driver outputs to one or more panel row inputs through a proprietary interface and can enable the use of fewer high voltage driver circuits in the high voltage driver. Each panel row input can drive one or more rows in a multi-touch panel. In some embodiments, the high voltage driver and decoder can be integrated into a single ASIC. However, in other embodiments the high voltage driver and decoder can be integrated into the driver logic, and in still other embodiments the high voltage driver and decoder can be eliminated entirely.
The computing system can also include a host processor for receiving outputs from the panel processor 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. The host processor can also perform additional functions that may not be related to panel processing, and can be coupled to program storage and a display device such as an LCD for providing a user interface (UI) to a user of the device.
As mentioned above, the multi-touch panel can in some embodiments include a capacitive sensing medium having 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 dimensions” 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 pass above and below each other (but do not make direct electrical contact with each other), the traces essentially form two electrodes. Each intersection of row and column traces can represent a capacitive sensing node and can be viewed as a picture element (pixel), which can be particularly useful when the multi-touch panel is viewed as capturing an “image” of touch. (In other words, after the panel subsystem has determined whether a touch event has been detected at each touch sensor in the multi-touch 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).) 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 the multi-touch panel can be detected by measuring changes to Csig. The columns of the multi-touch panel can drive one or more analog channels in the panel subsystem. In some embodiments, each column can be coupled to one dedicated analog channel. However, in other embodiments, the columns can be couplable via an analog switch to a fewer number of analog channels.
The touchscreen stackups described above can be advantageously used in the computing system to provide a space-efficient touch sensor panel and UI.
A number of different mobile telephones can include the touchscreen stackups and computing system described above according to embodiments of the invention. PSA can be used to bond the sensor panel to a display device (e.g. LCD module). A number of different digital audio/video players can also include the touchscreen stackups and computing system described above according to embodiments of the invention. These mobile telephones and digital audio/video players can advantageously benefit from the touchscreen stackups described above because the touchscreen stackups allow these devices to be smaller and less expensive, which can be 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 method for forming a multi-touch sensor panel, comprising:
- forming a plurality of first traces of substantially transparent conductive material on a first substrate;
- forming a plurality of second traces of the substantially transparent material;
- creating a fluid-tight gap between the plurality of first traces and the plurality of second traces;
- filling the fluid-tight gap with a fluid having substantially no bubbles and an optical index similar to the optical index of the first and second traces to make the gap and the first and second traces substantially transparent; and
- orienting the second and first traces to cross over each other at crossover locations separated by the fluid, the crossover locations forming mutual capacitance sensors for detecting touches.
2. The method of claim 1, wherein the first substrate is a cover glass having a first side capable of being touched, and a second side opposite the first side on which the plurality of first traces are formed.
3. The method of claim 2, further comprising forming the plurality of second traces on a second substrate.
4. The method of claim 1, further comprising creating the fluid-tight gap by forming compressible spacers between the first and second traces, the compressible spacers capable of being compressed during a touch and changing a mutual capacitance of the mutual capacitance sensors.
5. The method of claim 1, further comprising coupling a chip on glass to the first substrate, the chip on glass including sensor panel circuitry.
6. A method for forming a multi-touch sensor panel, comprising:
- forming a plurality of first traces and a plurality of second traces of substantially transparent conductive material;
- orienting the plurality of second and first traces to cross over each other at crossover locations, the crossover locations forming mutual capacitance sensors for detecting touches;
- separating the second and first traces by a fluid having substantially no bubbles and an optical index similar to the optical index of the first and second traces to make the first and second traces substantially transparent.
7. The method of claim 6, further comprising forming the plurality of first traces on a second side of a first substrate having a first side capable of being touched, the second side opposite the first side.
8. The method of claim 7, further comprising forming the plurality of second traces on a second substrate.
9. The method of claim 6, further comprising separating the second and first traces using compressible spacers, the compressible spacers capable of being compressed during a touch and changing a mutual capacitance of the mutual capacitance sensors.
10. The method of claim 7, further comprising coupling a chip on glass to the first substrate, the chip on glass including sensor panel circuitry.
11. A multi-touch sensor panel, comprising:
- a first substrate having a plurality of first traces of substantially transparent conductive material formed thereon;
- a plurality of second traces of the substantially transparent material;
- a fluid-tight gap formed between the plurality of first and second traces; and
- a fluid having substantially no bubbles and an optical index similar to the optical index of the plurality of first and second traces held within the fluid-tight gap, the fluid for making the gap and the plurality of first and second traces substantially transparent;
- wherein the plurality of first and second traces are oriented to cross over each other at crossover locations separated by the fluid, the crossover locations forming mutual capacitance sensors for detecting touches.
12. The multi-touch sensor panel of claim 11, wherein the first substrate is a cover glass having a first side capable of being touched, and a second side opposite the first side on which the plurality of first traces are formed.
13. The multi-touch sensor panel of claim 12, further comprising a second substrate having the plurality of second traces formed thereon.
14. The multi-touch sensor panel of claim 11, further comprising compressible spacers coupled between the plurality of first and second traces, the compressible spacers capable of being compressed during a touch and changing a mutual capacitance of the mutual capacitance sensors.
15. The multi-touch sensor panel of claim 11, further comprising a chip on glass coupled to the first substrate, the chip on glass including sensor panel circuitry.
16. The multi-touch sensor panel of claim 11, further comprising a liquid crystal display (LCD) module coupled to the multi-touch sensor panel.
17. The multi-touch sensor panel of claim 16, the multi-touch sensor panel incorporated into a computing system.
18. The multi-touch sensor panel of claim 17, the computing system incorporated into a mobile telephone.
19. The multi-touch sensor panel of claim 17, the computing system incorporated into a digital audio player.
20. A mobile telephone including a multi-touch sensor panel, the multi-touch sensor panel comprising:
- a first substrate having a plurality of first traces of substantially transparent conductive material formed thereon;
- a plurality of second traces of the substantially transparent material;
- a fluid-tight gap formed between the plurality of first and second traces; and
- a fluid having substantially no bubbles and an optical index similar to the optical index of the plurality of first and second traces held within the fluid-tight gap, the fluid for making the gap and the plurality of first and second traces substantially transparent;
- wherein the plurality of first and second traces are oriented to cross over each other at crossover locations separated by the fluid, the crossover locations forming mutual capacitance sensors for detecting touches.
21. A digital audio player including a multi-touch sensor panel, the multi-touch sensor panel comprising:
- a first substrate having a plurality of first traces of substantially transparent conductive material formed thereon;
- a plurality of second traces of the substantially transparent material;
- a fluid-tight gap formed between the plurality of first and second traces; and
- a fluid having substantially no bubbles and an optical index similar to the optical index of the plurality of first and second traces held within the fluid-tight gap, the fluid for making the gap and the plurality of first and second traces substantially transparent;
- wherein the plurality of first and second traces are oriented to cross over each other at crossover locations separated by the fluid, the crossover locations forming mutual capacitance sensors for detecting touches.
22. A multi-touch sensor panel, comprising:
- a plurality of first traces and a plurality of second traces of substantially transparent conductive material, the plurality of second and first traces oriented to cross over each other at crossover locations, the crossover locations forming mutual capacitance sensors for detecting touches; and
- a fluid separating the second and first traces, the fluid having substantially no bubbles and an optical index similar to the optical index of the first and second traces to make the first and second traces substantially transparent.
23. The multi-touch sensor panel of claim 22, further comprising a first substrate upon which the plurality of first traces are formed, the first substrate being a cover glass having a first side capable of being touched, and a second side opposite the first side upon which the plurality of first traces are formed.
24. The multi-touch sensor panel of claim 23, further comprising a second substrate having the plurality of second traces formed thereon.
25. The multi-touch sensor panel of claim 22, further comprising compressible spacers coupled between the plurality of first and second traces, the compressible spacers capable of being compressed during a touch and changing a mutual capacitance of the mutual capacitance sensors.
26. The multi-touch sensor panel of claim 22, further comprising a chip on glass coupled to the plurality of first traces, the chip on glass including sensor panel circuitry.
Type: Application
Filed: Jun 13, 2007
Publication Date: Jul 10, 2008
Applicant: Apple Inc. (Cupertino, CA)
Inventors: Steve Porter Hotelling (San Jose, CA), Brian Richards Land (Redwood City, CA), Mark Arthur Hamblin (San Francisco, CA)
Application Number: 11/818,335
International Classification: G06F 3/041 (20060101);