Single-layer touch-sensitive display

The present invention generally relates to an input device for a computing system, and more particularly to a reciprocal capacitance multi-touch sensor panel that can be manufactured on one side of a substrate.

Cross-references to related applications: This application is hereby incorporated by reference in US Provisional Patent Application Nos. 60 / 977,621 and 2008, filed October 4, 2007, both entitled "Single-Layer Touch-Sensitive Display". Claims priority for US Patent Application No. 12 / 038,760 filed on 27th March.

Many types of input devices such as buttons or keys, mice, trackballs, touch sensitive panels, joysticks, touch screens, etc. are now available to operate computing systems. In particular, touch screens are becoming more and more popular because they are easy to operate, versatile, and declining in price. The touch screen can include a touch sensor panel, which is a transparent panel with a touch sensing surface. The touch sensor panel can be placed in front of the display screen so that the touch sensitive surface covers the view area of the display screen. The touch screen allows the user to make selections and move the cursor by simply touching the display screen with a finger or stylus. In general, the touch screen can recognize the touch and the location of the touch on the display screen, and the computing system can interpret the touch and then perform an action based on the touch event.

<p> The touch sensor panel can be embodied as an array of pixels formed by the intersection of multiple drive lines (eg, rows) with multiple sense lines (eg, columns). Separated by a dielectric material. An example of such a touch sensor panel is incorporated herein by reference in a simultaneously pending US Patent Application No. 11 / 650,049 entitled "Double-Sided Touch Sensitive Panel and Flex Circuit Bonding" filed January 3, 2007. It is explained in. However, the touch sensing panel in which the drive line and the sense line are formed on the lower surface and the upper surface of the single substrate is expensive to manufacture. One reason for this additional cost is that the thin film processing steps must be performed on both sides of the glass substrate, and the treated side needs protective measures while processing the other side. .. Another reason is the cost of manufacturing and joining flexible circuits required to connect to both sides of the substrate.</p>

<p> The present invention is coplanar manufactured on one side of a substrate to detect single or multiple touch events (one or more fingers or other objects touching individual positions of a touch-sensitive surface at about the same time). It relates to a substantially transparent touch sensor panel having a single layer touch sensor. In order to avoid the need to produce substantially transparent drive wires and sense wires on both sides of the same substrate, embodiments of the present invention form drive wires and sense wires on the same plane single layer on the same side of the substrate. be able to. The drive line and sense line can be manufactured as a row pattern in the first direction and as a patch in the second direction, and each row pattern in the first direction is individual in the boundary area of the touch sensor panel. All patches in each of the multiple rows in the second direction are connected together using separate metal traces (or other conductive materials) in the boundary area of the touch sensor panel. To. The metal trace in the boundary area is formed on the same substrate side as the patch and row, but can be separated from the patch and row pattern by a dielectric layer. Metal traces allow both patches and row patterns to be routed to the same short edge of the board, allowing small flexible circuits to be joined to small areas on only one side of the board.</p>

<figref num="1A">FIG. 5 is a partial view illustrating a substantially transparent touch sensor panel having a coplanar single-layer touch sensor manufactured on one side of a substrate according to an embodiment of the present invention.</figref><figref num="1B">FIG. 5 is a partial view illustrating a substantially transparent touch sensor panel comprising a metal trace extending into a boundary area of the touch sensor panel according to an embodiment of the present invention.</figref><figref num="1C">It is a figure which illustrates connecting a column and a row patch to a metal trace in the boundary area of a touch sensor panel by one Embodiment of this invention.</figref><figref num="2A">FIG. 5 is a cross-sectional view of a touch sensor panel showing SITO traces and metal traces connected through vias of a dielectric material according to an embodiment of the present invention.</figref><figref num="2B">FIG. 5 is an enlarged view of a cross-sectional view of FIG. 2A according to an embodiment of the present invention.</figref><figref num="3">It is a top view which illustrates the column and the adjacent row patch by one Embodiment of this invention.</figref><figref num="4A">It is a plot of the x-coordinate of a finger touch and the mutual capacitance found in the pixels for two adjacent pixels a-5 and b-5 in a single row with wide spacing.</figref><figref num="4B">A plot of the x-coordinate of a finger touch and the mutual capacitance found in a pixel for two adjacent pixels a-5 and b-5 in a single row with wide spacing, one embodiment of the present invention. The case where spatial interpolation is performed depending on the form is shown.</figref><figref num="4C">FIG. 5 is a top view illustrating a column and adjacent row patch pattern useful for larger pixel spacing in one embodiment of the invention.</figref><figref num="5">It is a figure which illustrates the laminated body of SITO on the touch sensor panel substrate bonded to the cover glass by one Embodiment of this invention.</figref><figref num="6">It is a figure which illustrates the computing system which operates with the touch sensor panel by one Embodiment of this invention.</figref><figref num="7A">It is a figure which illustrates the mobile telephone which can include the touch sensor panel and the computing system by one Embodiment of this invention.</figref><figref num="7B">It is a figure which illustrates the digital audio / video player which can include the touch sensor panel and the computing system by one Embodiment of this invention.</figref>

In the following description of preferred embodiments, reference is made to the accompanying drawings illustrating specific embodiments in which the present invention can be carried out. It should be understood that other embodiments can be used and structural modifications are possible without departing from the scope of the invention.

The present invention is coplanar manufactured on one side of a substrate to detect single or multiple touch events (one or more fingers or other objects touching individual positions of a touch-sensitive surface at about the same time). It relates to a substantially transparent touch sensor panel having a single layer touch sensor. In order to avoid the need to produce substantially transparent drive wires and sense wires on both sides of the same substrate, embodiments of the present invention form drive wires and sense wires on the same plane single layer on the same side of the substrate. be able to. The drive line and sense line can be manufactured as a row pattern in the first direction and as a patch in the second direction, and each row pattern in the first direction is individual in the boundary area of the touch sensor panel. All patches in each of the multiple rows in the second direction are connected together using separate metal traces (or other conductive materials) in the boundary area of the touch sensor panel. To. The metal trace in the boundary area is formed on the same substrate side as the patch and row, but can be separated from the patch and row pattern by a dielectric layer. Metal traces allow both patches and row patterns to be routed to the same short edge of the board, allowing small flexible circuits to be joined to small areas on only one side of the board.

Although some embodiments of the present invention will be described here with respect to the mutual capacitance multi-touch sensor panel, the embodiments of the present invention are not limited to this, and are also applied to self-capacitance sensor panels and single touch sensor panels. Please understand what you can do. Further, the touch sensor in the sensor panel will be described herein with respect to an orthogonal array of touch sensors having rows and columns, but embodiments of the present invention are not limited to orthogonal arrays and are generally diagonal, concentric, concentric. It can be applied to touch sensors arranged in any number of dimensions and directions, including three-dimensional and random directions.

FIG. 1A is a partial view illustrating a substantially transparent touch sensor panel 100 having a coplanar single-layer touch sensor manufactured on one side of a substrate according to an embodiment of the present invention. In the embodiment of FIG. 1A, a touch sensor panel 100 with 8 columns (indicated by a to h) and 6 rows (indicated by 1 to 6) is shown, but it is understood that any number of columns and rows can be used. I want to be. Rows a through h are generally columnar in shape, but in the embodiment of FIG. 1A, one side of each row is designed to produce staggered edges and separate compartments for each row. including. Each of rows 1-6 can be formed by multiple separate patches or pads, each patch being a trace of the same material as the patch and routed to the boundary area of the touch sensor panel 100. Includes traces to allow all patches in a particular line to be connected together via a metal trace (not shown in Figure 1A) that extends into the boundary area. The metal trace can be routed to a small area on one side of the touch sensor panel 100 and connected to the flexible circuit 102. As shown in the examples of FIG. 1A, the patches forming the rows can generally be arranged in a pyramidal configuration. In FIG. 1A, for example, the patches for rows 1 to 3 between columns a and b are arranged in an inverted pyramid configuration, while the patches for rows 4 to 6 between columns a and b are upright pyramids. Arranged in composition.

The columns and patches of FIG. 1A can be formed in a coplanar single layer of conductive material. In the touch screen embodiment, the conductive material is a substantially transparent material such as single layer indium tin oxide (SITO), but other materials can also be used. The SITTO layer can be formed on the back surface of the cover glass or the top surface of the individual substrate. Although SITO is addressed herein for ease of disclosure, it should be understood that other conductive materials may also be used in embodiments of the present invention.

FIG. 1B is a partial view illustrating a substantially transparent touch sensor panel 100 including metal traces 104 and 106 extending into a boundary area of the touch sensor panel according to an embodiment of the present invention. The boundary area in Figure 1B has been enlarged for clarity. Each column a through h can include a SITO trace 108 that allows the column to be connected to the metal trace via vias (not shown in Figure 1B). One side of each row contains staggered edges 114, and a notch 116 designed to generate a separate compartment for each row. Patches 1 to 6 in each row can include SITO trace 110, which allows the patch to be attached to the metal trace via vias (not shown in Figure 1B). This SITO trace 110 allows each patch on a particular line to self-connect to each other. Since the metal tracks 104 and 106 are all formed in the same layer, they can all be routed to the same flexible circuit 102.

When the touch sensor panel 100 acts as a touch sensor panel with mutual capacitance, columns ah or rows 1-6 can be driven by one or more stimulus signals, and adjacent column areas and row patches. Fringe lines of force can be formed between them. In FIG. 1B, for explanation, only the line of force 112 between column a and row patch 1 (a-1) is shown, but with other adjacent columns based on what column or row is stimulated. It should also be understood that lines of force can be formed between row patches (eg, a-2, b-4, g-5, etc.). Thus, each column-row patch pair (eg, a-1, a-2, b-4, g-5, etc.) represents a two-electrode pixel or sensor where charge can be coupled from the drive electrode to the sense electrode. Please understand that. When a finger touches one of these pixels, some of the fringed lines of force extending beyond the cover of the touch sensor panel are blocked by the finger, reducing the amount of charge bound to the sense electrode. Such a decrease in the amount of charge bound can be detected as a determinant of the "picture" that results from the touch. A touch sensor panel design with mutual capacitance as shown in FIG. 1B does not require a separate reference ground, and therefore does not require a second layer on the back side of the board or on a separate board.

The touch sensor panel 100 can also operate as a self-capacitance touch sensor panel. In such an embodiment, the reference ground plane is formed on the back side of the substrate, separated from the patch and row by a dielectric on the same side as the patch and row, or formed on a separate substrate. Can be done. In a self-capacitance touch sensor panel, each pixel or sensor has a self-capacitance that changes with the presence of a finger with respect to the reference ground. In the self-capacitance embodiment, the self-capacitance of column ah can be sensed independently, and the self-capacitance of rows 1-6 can also be sensed independently.

FIG. 1C is a diagram illustrating the connection of column and row patches to metal traces in the boundary area of a touch sensor panel according to an embodiment of the present invention. FIG. 1C represents "detail A" shown in FIG. 1B, showing column "a" and row patch 4-6 connected to metal trace 118 through SITO traces 108 and 110. Since the SITO traces 108 and 110 are separated from the metal trace 118 by the dielectric material, the via 120 formed on the dielectric material allows the SITO trace to be connected to the metal trace.

FIG. 2A is a cross-sectional view of the touch sensor panel 200 showing SITO traces 208 and metal traces 218 connected through via 220 of dielectric material 222 according to embodiments of the present invention. FIG. 2A represents the BB cross section shown in FIG. 1C.

FIG. 2B is an enlarged view of the cross section shown in FIG. 2A according to the embodiment of the present invention. FIG. 2B illustrates an embodiment in which the SITO trace 208 has a resistivity of up to about 155 ohms / square. In one embodiment, the dielectric 222 is an inorganic SiO of about 1500 Å.₂It can be processed at high temperatures and therefore the SITO layer can be sputtered with high quality. In another embodiment, the dielectric 222 is an organic polymer of about 3.0 microns. 1500 Å of inorganic SiO₂Can be used for touch sensor panels small enough that crossover capacitance (between SITO trace 208 and metal trace 218) is not an issue.

For large touch sensor panels (diagonal dimension greater than or equal to about 3.5 "), crossover capacitance becomes an issue and produces error signals that can only be partially compensated. Therefore, for large touch sensor panels, A thick dielectric layer 222 with a low dielectric constant, such as an organic polymer of about 3.0 microns, can be used to reduce the crossover capacitance, however, the use of a thick dielectric layer forces the SITO layer at low temperatures. Spatters into a low optical quality and high resistance.

Again, referring to the example in Figure 1C, column edge 114 and row patch 4-6 can be inconsistent in the x-dimensional. This is because space must be created for SITO trace 110 to connect line patches 4 and 5. (It should be understood that line patch 4 in the example of Figure 1C is actually two patches pasted together.) Pixels a-6, a- for optimum touch sensitivity. It is desirable to balance the area of the electrodes in 5 and a-4. However, if column "a" is held straight, row patch 6 can be made thinner than row patch 5 or 6, resulting in an imbalance between the electrodes of pixel a-6.

FIG. 3 is a top view of a column and adjacent row patch according to an embodiment of the present invention. It is generally desired that the mutual capacitance characteristics of pixels a-4, a-5 and a-6 be relatively constant in order to produce a relatively uniform z-direction touch sensitivity that remains within the range of the touch sensing circuit. Therefore, the column area a₄, A₅And a₆Should be approximately the same as the row patch areas 4, 5 and 6. To achieve this, column division a₄And a₅, And row patches 4 and 5 have column divisions a₆And column segment a, shrinking in the y direction compared to row patch 6₄Area of column segment a₅And a₆Can be matched to the area of. In other words, pixel a₄-4 is a narrow and tall pixel a₆It is wider and shorter than -6.

From the above figures, it is clear that the raw spatial sensitivity is slightly distorted. In other words, the pixel or sensor is slightly skewed or misaligned in the x direction, so the x coordinate of the maximum touch event at pixel a-6 (eg, a finger placed directly above pixel a-6) is For example, it may be slightly different from the x-coordinate of the maximum touch event at pixel a-4. Therefore, in embodiments of the present invention, this misalignment can be de-warped by a software algorithm to remap the pixels and remove distortion.

A typical touch panel grid dimension has pixels centered at 5.0 mm, but to reduce the total number of electrical connections in the touch sensor panel, for example, a more dispersed grid with a center of about 6.0 mm desired. However, if the sensor patterns are dispersed, the touch reading may be erroneous.

FIG. 4A plots the x-coordinate of a finger touch and the mutual capacitance found in the pixels for two adjacent pixels a-5 and b-5 in a single row with wide spacing. In FIG. 4A, plot 400 represents the mutual capacitance seen at pixel a-5 as the finger touch moves continuously from left to right, and plot 402 shows the finger touch moving continuously from left to right. Represents the mutual capacitance found in pixel b-5 when As expected, when a finger touch passes directly above pixel a-5, pixel a-5 sees a drop in mutual capacitance of 404, and when finger touch passes directly above pixel b-5. A drop in mutual capacitance of 406 can be seen at pixel b-5. When line 408 represents a threshold for detecting a touch event, Figure 4A erroneously indicates that the finger was momentarily lifted from the surface, even though the finger was not lifted from the surface of the touch sensor panel. It shows that it appears. This position 410 can represent a point approximately midway between two dispersed pixels.

Figure 4B is a plot of the x-coordinate of a finger touch and the mutual capacitance found in the pixels for two adjacent pixels a-5 and b-5 in a single row with wide spacing. A case where spatial interpolation is performed according to the embodiment of the present invention is shown. As expected, when a finger touch passes directly above pixel a-5, pixel a-5 sees a drop in mutual capacitance of 404, and when finger touch passes directly above pixel b-5. A drop in mutual capacitance of 406 can be seen at pixel b-5. However, it should be noted that the increase and decrease of the mutual capacitance value occurs more gradually than in the case of FIG. 4A. When line 408 represents a threshold for detecting a touch event, Figure 4B shows that the touch event is always pixel a-5 as the finger moves over pixels a-5 and b-5 from left to right. Or it indicates that it is detected by b-5. In other words, this "blurring" of touch events helps prevent the appearance of false non-touch readings.

In one embodiment of the invention, the thickness of the cover glass for the touch sensor panel can be increased to produce some or all of the spatial blur or filtering shown in FIG. 4B.

FIG. 4C is a top view illustrating column and adjacent row patch patterns that are useful for larger pixel spacing according to embodiments of the present invention. FIG. 4C illustrates an embodiment in which the serrated electrode edge 412 is used within a pixel extending in the x direction. The serrated electrode edge allows the fringe electric field line 414 to be present in the x direction over a large area so that touch events can be detected by the same pixel over a large distance in the x direction. It should be understood that the serrated configuration in Figure 4C is merely an example, and that other configurations such as winding edges can be used. These configurations can further soften the touch pattern and generate additional spatial filtering and interpolation between adjacent pixels as shown in FIG. 4B.

FIG. 5 is a diagram illustrating a laminate of SITO on a touch sensor panel substrate bonded to a cover glass according to an embodiment of the present invention. This laminate comprises a touch sensor panel substrate 500 that can be formed of glass, on one side of which an antireflection (AR) film 510 can be formed, and on the other side a metal 502 is deposited and patterned to form a boundary. Bus lines can be formed in the area. Metal 502 has a maximum resistivity of 0.8 Ω / sq. The insulating layer 504 can then be deposited on the substrate 500 and the metal 502. The insulating layer is, for example, a SiO with a thickness of 1500 Å.₂Or is a 3μ organic polymer. Photolithography can be used to form via 506 on insulation 504, and conductive material 508 can be deposited and patterned on top of insulation and metal 502. A single layer 508 of conductive material that can be formed from a transparent conductive material such as ITO with a resistivity of up to 155 Ω / square is more transparent and easier to manufacture than a multi-layer design. Adhesive 514, such as an anisotropic conductive film (ACF), can be used to bond the flexible circuit 512 to the conductive material 508 and metal 502. The entire subassembly can then be joined to the cover glass 516 and the black mask 520 using an adhesive 518 such as pressure sensitive adhesive (PSA).

In another embodiment, the metal, insulating material, conductive material described above can be formed directly on the back surface of the cover glass.

FIG. 6 is a diagram illustrating a computing system 600 that can operate with the touch sensor panel according to the embodiment of the present invention. A touch screen 642, which can include a touch sensor panel 624 and a display device 640 (eg, an LCD module), is a computing system 600 through a connector integrally formed with the sensor panel or using a flexible circuit. You can connect to other components in. The computing system 600 can include one or more panel processors 602 and peripherals 604, as well as a panel subsystem 606. One or more processors 602 can include, for example, the ARM968 processor, or other processors with similar functionality and capabilities. However, in other embodiments, the functionality of the panel processor can also be embodied by dedicated logic such as a state machine. Peripheral device 604 can include, but is not limited to, random access memory (RAM), or other form of memory or storage device, watchdog timer, and the like.

The panel subsystem 606 can include, but is not limited to, one or more analog channels 608, channel scan logic 610 and driver logic 614. The channel scan logic 610 accesses the RAM 612, autonomously reads data from the analog channels, and gives control for the analog channels. This control involves multiplexing and otherwise connecting the sense wire of the touch sensor panel 624 to analog channel 608. Further, the channel scan logic 610 can control the driver logic and the stimulation signal selectively applied to the drive line of the touch sensor panel 624. In certain embodiments, the panel subsystem 606, panel processor 602 and peripheral device 604 can be integrated into a single application specific integrated circuit (ASIC).

The driver logic 614 can generate multiple panel subsystem outputs 616 and provide a dedicated interface to drive the high voltage driver 618. The high voltage driver 618 provides a level shift from low voltage levels (eg complementary metal oxide semiconductor (CMOS) levels) to high voltage levels to provide a good signal-to-noise ratio (S / N) for noise reduction purposes. Can be given. Panel subsystem output 616 can be sent to decoder 620 and level shifter / driver 638, which selectively direct one or more high voltage driver outputs to one or more panel row or drive line inputs 622 through a dedicated interface. Connect to and enable the use of a small number of high voltage driver circuits in the high voltage driver 618. Each panel row input 622 can drive one or more drive lines within the touch sensor panel 624. In certain embodiments, the high voltage driver 618 and decoder 620 can be integrated into a single ASIC. However, in other embodiments, the high voltage driver 618 and decoder 620 can be integrated into the driver logic 614, and in yet another embodiment the high voltage driver 618 and decoder 620 can be completely eliminated. ..

The computing system 600 may also include a host processor 628 for receiving output from the panel processor 602 and performing an action based on that output, the action of which is of a cursor or pointer. Move such objects, scroll or pan, adjust control settings, open files or documents, view menus, make selections, perform instructions, and operate peripherals connected to the host device. , Answer phone calls, make phone calls, end phone calls, change volume or voice settings, related to phone communications like address, frequently dialed numbers, received calls, missed calls Stores the information provided, logs it to the computer or computer network, allows authorized individuals to access the restricted area of the computer or computer network, loads the user profile associated with the user's preferred configuration of the computer desktop, and loads the user profile. It can allow access to web content, launch specific programs, encrypt or decrypt messages, etc. The host processor 628 can also perform additional functions unrelated to panel processing, as well as a program storage device 632 and a display device 640 such as an LCD to provide the user of the device with a user interface (UI). You can connect.

The touch sensor panels described above have been incorporated into the system of Figure 6 to form a space efficient touch sensor panel and UI that is low cost, easy to manufacture and fits into existing mechanical control outlines (same physical jacket). It can be used conveniently.

FIG. 7A is a mobile phone that can include a laminate of the touch sensor panel 724 and display device 730 described above according to an embodiment of the invention (optionally joined together using PSA734) and a computing system. 736 is illustrated. FIG. 7B can include a stack of touch sensor panels 724 and display device 730 described above according to embodiments of the present invention (optionally joined together using PSA734) as well as a computing system. / Video player 740 is illustrated. The mobile phones and digital audio / video players of FIGS. 7A and 7B can conveniently benefit from the touch sensor panels described above. This is because touch sensor panels can make these devices small and inexpensive, as they are important consumer factors that have a significant impact on consumer wishes and commercial success.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, those skilled in the art will appreciate various changes and modifications. It is understood that such changes and amendments are included within the scope of the embodiments of the invention as defined by the claims.

100: Touch sensor panel 102: Flexible circuit 104, 106: Metal trace 108, 110: SITO trace 112: Electric field line 114: Staggered edge 116: Notch 120: Via 200: Touch sensor panel 208: SITO trace 218: Metal Trace 220: Via 222: Dielectric material 404, 406: Mutual capacitance 412: Sawtooth electrode edge 414: Fringe electric field line