US20150346873A1

US20150346873A1 - Capacitive touch panel having improved response characteristics

Info

Publication number: US20150346873A1
Application number: US14/818,073
Authority: US
Inventors: Nathan Y. Moyal; Tao Peng; Jerry L. Doorenbos; Ronald F. Cormier
Original assignee: Texas Instruments Inc
Current assignee: Texas Instruments Inc
Priority date: 2012-07-23
Filing date: 2015-08-04
Publication date: 2015-12-03
Also published as: US9128571B2; US20140022200A1

Abstract

An apparatus is provided. The apparatus comprises a second layer disposed over a first layer. Each of the first and second layers have a set of detection electrodes that are spaced apart and electrically isolated from one another and an associated set of interleavers. Each interleaver is located between adjacent detection electrodes from its associated the set of detection electrodes, and each set of interleavers also includes a pair of complementary interleaving electrodes coupled to those that are electrically coupled to the adjacent detection electrodes from its associated set of detection electrodes. The detection electrodes and interleaving electrodes are also substantially transparent to visible spectrum light.

Description

CROSS-REFERENCE TO RELATED APPLICATION

Under 35 U.S.C. §120, this continuation application claims priority to and the benefit of U.S. patent application Ser. No. 13/555,556, filed on Jul. 23, 2012 and entitled “CAPACITIVE TOUCH PANEL HAVING IMPROVED RESPONSE CHARACTERISTICS,” the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates generally to a touch panel and, more particularly, to a capacitive touch panel having an improved response.

BACKGROUND

Turning to FIGS. 1 and 2, an example of a conventional system 100 can be seen. System 100 generally comprises a touch panel 102 and touch panel controller 104. The touch panel 102 has an array of sensors formed by a set of column electrodes (e.g., electrode 103), where each electrode of each column is coupled together by a strip electrode (e.g., strip electrode 107), and a set of row electrodes (e.g., electrode 109), where each electrode of each row is coupled together by a strip electrode (e.g., strip electrode 107). Usually, the column and row electrodes (e.g., electrodes 103 and 105) are formed in two separate layers with a dielectric or insulating layer formed therebetween, and these conductive layers which form the electrodes (e.g., electrodes 105 and 109) are generally transparent to visible spectrum light (e.g., light having a wavelength from about 380 nm to about 750 nm). The strip electrodes for each column (e.g., strip electrode 107) are then coupled to the interface or I/F 106 of the touch panel controller 104 by terminals X-1 to X-N, while the strip electrodes for each row (e.g., strip electrode 109) are coupled to the interface 106 by terminals Y-1 to Y-M. The interface 106 is able to communicate with the control circuit 108. As shown in greater detail in FIG. 2, the interface 106 is generally comprised of a multiplexer or mux 202 and an exciter 204.
In operation, the interface 106 (which is usually controlled by the control circuit 108) selects and excites columns of electrodes (e.g., electrode 103) and “scans through” the rows of row electrodes (e.g., electrode 105) so that a touch position from a touch event can be resolved. As an example, interface 204 can excite two adjacent columns through terminals X-j and X-(j+1) with excitation signals EXCITE[j] and EXCITE[j+1], and interface 106 receives a measurement signal from a row associated with terminal Y-i. When an object (e.g., finger) is in proximity to the touch panel (which is generally considered to be a touch event), there is a change in capacitance due at least in part to the arrangement of electrodes (e.g., electrodes 103 and 105), and the controller 108 is able to resolve the position of the touch event.
Most conventional touch panels (e.g., touch panel 102) do, however, exhibit a non-uniform response characteristic, which is manifested as non-uniform signal strength across the panel. This non-uniformity is generally caused by natural variations in the patterns forming the column and row electrodes (e.g., electrodes 103 and 105). In other words, the electrodes are arranged to have gaps or non-overlapping regions between the electrodes so that, as an object (e.g., finger) traverses the panel (e.g., panel 102) and passes over these non-overlapping regions, the signal strength or measured capacitance changes. Therefore, there is a need for a touch panel having a more uniform response characteristic.
Some examples of other conventional systems are: U.S. Patent Pre-Grant Publ. No. 2011/0095996; U.S. Patent Pre-Grant Publ. No. 2011/0095997; U.S. Patent Pre-Grant Publ. No. 2011/0102361; and U.S. Patent Pre-Grant Publ. No. 2011/0157079.

SUMMARY

An embodiment of the present disclosure, accordingly, provides an apparatus. The apparatus comprises a first layer having: a first set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the first set of detection electrodes is substantially transparent to visible spectrum light; and a first set of interleavers, wherein each interleaver from the first set of interleavers is located between adjacent detection electrodes from the first set of detection electrodes, and wherein each interleaver from the first set of interleavers includes: a first set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the first set of interleaving electrodes is substantially transparent to visible spectrum light; and a second set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the second set of interleaving electrodes is substantially transparent to visible spectrum light; and a second layer that is disposed over the first layer, wherein the second layer has: a second set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the second set of detection electrodes is substantially transparent to visible spectrum light; and a second set of interleavers, wherein each interleaver from the second set of interleavers is located between adjacent detection electrodes from the second set of detection electrodes, and wherein each interleaver from the second set of interleavers includes: a third set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the third set of interleaving electrodes is substantially transparent to visible spectrum light; and a fourth set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the fourth set of interleaving electrodes is substantially transparent to visible spectrum light.
In accordance with an embodiment of the present disclosure, the first layer further comprises: a substrate that is substantially transparent to visible spectrum light; a conductive layer disposed over the substrate, wherein the conductive layer is patterned to form the first sets of detection electrodes and interleavers; and an insulating layer disposed over the conductive layer.
In accordance with an embodiment of the present disclosure, the conductive layer further comprises a first conductive layer, and wherein the insulating layer further comprises a first insulating layer, and wherein the second layer further comprises: a second conductive layer disposed over the first layer, wherein the second conductive layer is patterned to form the second sets of detection electrodes and interleavers; and a second insulating layer disposed over the conductive layer.
In accordance with an embodiment of the present disclosure, the first set of detection electrodes further comprises a first set of strip electrodes that are substantially parallel with one another and are oriented in a first direction, and wherein the second set of detection electrodes further comprises a second set of strip electrodes that are substantially parallel to one another and oriented in a second direction, and wherein the orientation of the first and second sets of strip electrodes with respect to one another forms a plurality of non-overlapping zones.
In accordance with an embodiment of the present disclosure, the first direction is substantially perpendicular to the second direction.
In accordance with an embodiment of the present disclosure, complementary pairs of interleaving electrodes from at least one of the first and second sets of interleaving electrodes and the third and fourth sets of interleaving electrodes are located in each non-overlapping zone.
In accordance with an embodiment of the present disclosure, each interleaving electrode is substantially rectangular in shape.
In accordance with an embodiment of the present disclosure, each interleaving electrode is substantially triangular in shape.
In accordance with an embodiment of the present disclosure, the first and second sets of strip electrodes further comprise first and second sets of linear strip electrodes.
In accordance with an embodiment of the present disclosure, the first and second sets of strip electrodes further comprise first and second sets of diamond strip electrodes.
In accordance with an embodiment of the present disclosure, the complementary pairs of interleaving electrodes from the first and second sets of interleaving electrodes and from the third and fourth sets of interleaving electrodes are located in each non-overlapping zone.
In accordance with an embodiment of the present disclosure, an apparatus is provided. The apparatus comprises a touch panel screen having a touch sensor disposed over a display, wherein the touch sensor has: a first layer having: a first set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the first set of detection electrodes is substantially transparent to visible spectrum light; and a first set of interleavers, wherein each interleaver from the first set of interleavers is located between adjacent detection electrodes from the first set of detection electrodes, and wherein each interleaver from the first set of interleavers includes: a first set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the first set of interleaving electrodes is substantially transparent to visible spectrum light; and a second set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the first set of detection electrodes, wherein each interleaving electrode from the second set of interleaving electrodes is substantially transparent to visible spectrum light; and a second layer that is disposed over the first layer, wherein the second layer has: a second set of detection electrodes that are spaced apart and electrically isolated from one another, wherein each detection electrode from the second set of detection electrodes is substantially transparent to visible spectrum light; and a second set of interleavers, wherein each interleaver from the second set of interleavers is located between adjacent detection electrodes from the second set of detection electrodes, and wherein each interleaver from the second set of interleavers includes: a third set of interleaving electrodes that are electrically coupled to one of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the third set of interleaving electrodes is substantially transparent to visible spectrum light; and a fourth set of interleaving electrodes that are electrically coupled to the other of its adjacent detection electrodes from the second set of detection electrodes, wherein each interleaving electrode from the fourth set of interleaving electrodes is substantially transparent to visible spectrum light; and a touch panel controller that is electrically coupled to the first and second sets of detection electrodes.
In accordance with the present disclosure, the first set of interleaving electrodes form a first set of first serpentines with its detection electrodes, and wherein the second set of interleaving electrodes form a second set of serpentines with its detection electrodes, and wherein each first serpentine is interleaved with at least one second serpentine.
In accordance with the present disclosure, the third and forth interleaving electrodes form a zig-zag pattern the overlaps the interleaved first and second serpentines.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIGS. 1 and 2 are diagrams of an example of a conventional system;

FIG. 3 is a diagram of an example of a system in accordance with the present disclosure;

FIG. 4 is a cross-sectional view of a touch panel of FIG. 3 along section line I-I;

FIGS. 5 and 6 are plan views of portions of the section of the touch panel depicted in FIG. 4; and

FIGS. 7-20 are examples of the plan views shown in FIGS. 5 and 6.

DETAILED DESCRIPTION

Refer now to the drawings wherein depicted elements are, for the sake of clarity, not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.
Turning to FIG. 3, an example of a system 200 in accordance with an embodiment of the present disclosure can be seen. System 200 is similar in construction to system 100 except that touch panel 102 has been replaced by touch panel 202. Additionally, interconnect 204 has been provided to provide communication channels between the touch panel controller 104 and the touch panel 202.
In FIG. 4, a cross sectional view for section 206 of touch panel can be seen. As shown in this example, the touch panel 202 is generally comprised of a touch sensor 322 disposed over or positioned over a display 316 (which can, for example be a liquid crystal display or LCD) so as to allow the light from the display to project through the sensor 322. This means that each layer of the sensor 322 is substantially transparent to visible spectrum light. As shown, the touch sensor 322 is a dual or two layer sensor, having a row layer 320, column layer 318, and cover plate 314. The column and row layers 318 and 320, in this example, each have a conductive layer 304 and 310 (respectively) disposed on a substrate 302 and 308 (respectively), but one of the substrates 302 or 308 may be used instead of two. Typically, the substrates 302 and 308 are formed of glass (which is substantially transparent to visible spectrum light), and the conductive layers 310 and 304 are usually formed of a conductive material that is generally transparent to visible spectrum light (such as indium tin oxide, aluminum doped zinc oxide, gallium doped zinc oxide, or indium doped zinc oxide). Conductive layers 304 and 310 are also usually formed by electron beam evaporation, physical vapor deposition (PVD), or sputter deposition on the substrates 302 and 308, which can, for example, then be patterned using laser ablation or etching so to form the detection electrodes. The row and column layers 320 and 318 can then be secured to one another and the cover plate 314, using an insulating or dielectric material (which can be an adhesive, like epoxy).
In order to achieve a more uniform response characteristic for the touch sensor 322, the patterns for the conductors 304 and 310 should be modified. As shown in the example of FIGS. 5 and 6, row and column interleavers 404 and 504 (respectively) are introduced between adjacent rows (e.g., rows 402-1 and 402-2) and adjacent columns (e.g., columns 502-1 and 502-2) across the touch sensor 322. The interleavers (e.g., 404 and 504) can vary in configuration based on the shape or configuration of the conductors 304 and 310 but are intended to reduce the size (and, thus, the impact) of the non-overlapping zones and produce a generally uniform response characteristic across the touch sensor 322.
In FIGS. 7-9, an example of an arrangement for the row and column interleavers 404 and 504 is shown (which are labeled 404-A and 504-A, respectively) for section 206-A. In this example, row electrodes 402-A1 and 402-A2 are combined with row interleaver 404-A so as to form serpentine electrodes that are interleaved with one another. The row layer 320-A can also (optionally) include floating regions (e.g., floating region 406) interspersed between sections of the row interleaver 404-A, which can improve optical characteristics and response of the sensor (e.g., 322). Overlapping the row electrodes 402-A1 and 402-A2 and row interleaver 404-A are the column electrodes 502-A1 and 502-A2 and column interleaver 504-A that are arranged in a zig-zag or “fishbone” pattern.
Turning to FIGS. 10-12, another example of an arrangement for the row and column interleavers 404 and 504 (which are labeled 404-B and 504-B, respectively) for section 206 (which is labeled 206-B) can be seen. For this example, column electrodes 502-B1 and 502-B2 and row electrodes 402-B1 and 402-B2 are linear strip conductors that are oriented in different directions so as to be perpendicular to one another. Because linear strip electrodes are employed, the non-overlapping region 602-B is large. So, the row and column interleavers 404-A and 502-A are each formed of complementary pairs of interleaving electrodes that are each electrically coupled to a corresponding electrode (e.g., 402-A1) and that extend into the non-overlapping region 602-B. These complementary pairs of interleaving electrodes, however, remain electrically isolated from one another. By doing this, the effect that the non-overlapping region has on the performance of the touch sensor 322 can be greatly reduced. Alternatively, as shown in FIGS. 13 and 14, all of the complementary pairs of interleaving electrodes do not need to be within the non-overlapping region (as shown with region 602-C), but some (e.g., interleaving electrodes for column interleaver 504-C in column layer 318-C) may be in proximity or substantially over/under corresponding electrodes (e.g., row electrode 402-1) in a staggered pattern.
Additionally, as shown in FIGS. 15-17, the interleaving electrodes may take a variety of shapes. With section 206-B and 206-C (which are described above), the interleaving electrodes are substantially rectangular in shape, but it may be advantageous to employ other shapes. In the example shown in FIGS. 15-17, row interleaver 404-D and column interleaver 504-D employ triangular shaped interleaving electrodes.
The interleaving electrodes may also be employed with various detection electrode shapes as well. In the example shown in FIGS. 18-20, the column electrodes 502-E1 and 502-E2 and row electrodes 402-E1 and 402-E2 are arranged as diamond strip electrodes (similar to the configuration shown with touch panel 102) that are oriented in different directions so as to be perpendicular to one another. In this example, the interleaving electrodes for the column interleaver 504-E and row interleaver 404-E are positioned on the edges of the diamonds in the column electrodes 502-E1 and 502-E2 and row electrodes 402-E1 and 402-E2. This allows the performance of a touch sensor 322 with good response characteristics (e.g., use of diamond strip electrodes) can be further improved.
Having thus described the present disclosure by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.

Claims

What is claimed is:

1. A touch panel sensor comprising:

a first detection electrode extending longitudinally;

a second detection electrode extending longitudinally and parallel with the first detection electrode, the second detection electrode spaced apart and electrically isolated from the first detection electrode;

a first set of interleaving electrodes extending from the first detection electrode without contacting the second detection electrode; and

a second set of interleaving electrodes extending from the second detection electrode without contacting the first detection electrode, the second set of interleaving electrodes interleaving with the first set of interleaving electrodes.

2. The touch panel sensor of claim 1, wherein the first detection electrode, the second detection electrode, the first set of interleaving electrodes, and the second set of interleaving electrodes are substantially transparent to visible spectrum light.

3. The touch panel sensor of claim 1, wherein:

the first set of interleaving electrodes are substantially perpendicular to the first and second detection electrodes; and

the second set of interleaving electrodes are substantially parallel with the first set of interleaving electrodes and substantially perpendicular to the first and second detection electrodes.

4. The touch panel sensor of claim 1, wherein the first set of interleaving electrodes from a first serpentine conductor with the first detection electrode, and the second set of interleaving electrodes from a second serpentine conductor with the second electrode.

5. The touch panel sensor of claim 1, wherein each of the first and second set of interleaving electrodes is substantially rectangular in shape.

6. The touch panel sensor of claim 1, wherein each of the first and second set of interleaving electrodes is substantially triangular in shape.

7. The touch panel sensor of claim 1, further comprising:

a first detection layer having:

a first substrate substantially transparent to visible spectrum light; and

a first conductive layer disposed on the first substrate and patterned to form the first and second detection electrodes and the first and second interleave electrodes in a horizontal direction; and

a second detection layer aligned with the first detection layer in a vertical direction perpendicular to the horizontal direction, the second detection layer having:

a second substrate substantially transparent to the visible spectrum light; and

a second conductive layer disposed on the second substrate and pattern to form third and fourth detection electrodes partially overlapping with the first and second electrodes along the horizontal direction.

8. The touch panel sensor of claim 7, wherein:

the third detection electrode is substantially perpendicular to the first and second detection electrodes along the horizontal direction and has a first extended electrode extending parallel with the first and second detection electrodes along the horizontal direction; and

the fourth detection electrode is arranged parallel with the third detection electrode, the fourth detection electrode is substantially perpendicular to the first and second detection electrodes along the horizontal direction and has a second extended electrode extending parallel with the first and second detection electrodes along the horizontal direction.

9. The touch panel sensor of claim 8, wherein:

the first extended electrode partially overlaps with the first and second sets of interleaving electrodes along the horizontal direction; and

the second extended electrode partially overlaps with the first and second sets of interleaving electrodes along the horizontal direction.

10. A display panel comprising:

a display screen operative to project visible light;

a first detection layer vertically aligned with the display screen and substantially transparent to the projected visible light, the first detection layer having:

a first detection electrode extending longitudinally along a first horizontal direction parallel with the display screen;

a second set of interleaving electrodes extending from the second detection electrode without contacting the first detection electrode, the second set of interleaving electrodes interleaving with the first set of interleaving electrodes; and

a second detection layer vertically aligned with the display screen and the first detection layer, the second detection layer substantially transparent to the projected visible light and configured to sense a touch event along a second horizontal direction substantially perpendicular to the first horizontal direction.

11. The display panel of claim 10, further comprising:

an insulation layer positioned between the first detection layer and the second detection layer.

12. The display panel of claim 10, wherein:

13. The display panel of claim 10, wherein the first set of interleaving electrodes from a first serpentine conductor with the first detection electrode, and the second set of interleaving electrodes from a second serpentine conductor with the second electrode.

14. The display panel of claim 1, wherein each of the first and second set of interleaving electrodes is substantially rectangular in shape.

15. The display panel of claim 1, wherein each of the first and second set of interleaving electrodes is substantially triangular in shape.

16. The display panel of claim 1, wherein the second detection layer includes:

a third detection electrode isolated from and substantially perpendicular to the first and second electrodes, the third detection electrode having a first extended electrode extending parallel with the first and second detection electrodes; and

a fourth detection electrode isolated from and substantially perpendicular to the first and second electrodes, the fourth detection electrode having a second extended electrode extending parallel with the first and second detection electrodes without interleaving with the first extended electrode.

17. A display system comprising:

a display screen operative to project visible light;

a touch panel vertically aligned with the display screen and substantially transparent to the projected visible light, the touch panel having:

a first detection electrode extending longitudinally along a horizontal direction parallel with the display screen;

a control circuit coupled with the touch panel to detect a capacitance change in the first detection electrode and the second detection electrode.

18. The display system of claim 17, wherein:

19. The display system of claim 17, wherein the first set of interleaving electrodes from a first serpentine conductor with the first detection electrode, and the second set of interleaving electrodes from a second serpentine conductor with the second electrode.

20. The display system of claim 17, further comprising:

a row detection layer having:

a first substrate substantially transparent to the projected visible light; and

a first conductive layer disposed on the first substrate and patterned to form the first and second detection electrodes and the first and second interleave electrodes along a row direction; and

a column detection layer vertically aligned with the row detection layer, the column detection layer having:

a second substrate substantially transparent to the projected visible light; and

a second conductive layer disposed on the second substrate and pattern to form third and fourth detection electrodes partially overlapping with the first and second electrodes along a column direction perpendicular to the row direction.