Sensor patterns for mutual capacitance touchscreens

• US 9,075,484 B2
• Filed: 06/02/2009
• Issued: 07/07/2015
• Est. Priority Date: 06/02/2009
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Ritter, Robert, Brewer, Kenneth, Souchkov, Vitali, Narasimhan, Sarangan
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Shapiro, Leonid
• Application Number:
  US12/476,690
• Publication Number:
  US 20100302201A1
• Time in Patent Office: 2,226 Days
• Field of Search: 345/174, 345/156, 345/104
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

According to one embodiment, there is provided a mutual capacitance touchscreen comprising a first set of electrically conductive traces arranged in rows or columns and a second set of electrically conductive traces arranged in rows or columns arranged at right angles with respect to the rows or columns of the first set, where the first and second sets of traces are electrically insulated from and interdigitated respecting one another, and gaps between the first and second sets of traces form boundaries between the first and second sets of traces that undulate and that are not straight or linear. Other embodiments of a mutual capacitance touchscreen are also disclosed, such as “mini-diamond” sensor array patterns and sensor array patterns that may be manufactured at low cost.

Claims

1. A mutual capacitance touchscreen, comprising:

a first set of electrically conductive traces arranged in rows or columns, and

a second set of electrically conductive traces arranged in rows or columns arranged at an angle with respect to the rows or columns of the first set;

wherein the first and second sets of traces are electrically insulated from another, each cell comprising a plurality of sub-cell rectangular or square drive electrodes electrically connected to one another by first cross-over traces and a plurality of sub-cell rectangular or square sense electrodes electrically connected to one another by second cross-over traces, the sub-cell drive and sense electrodes being interleaved with respect to, and disposed in between, one another within each cell, the sub-cell sense and drive electrodes being separated by gaps within each cell, the first and second sets of electrically conductive traces comprising and being electrically connected to the drive and sense electrodes;

wherein the sub-cell rectangular or square drive or sense electrodes each form a pattern having an unfilled empty center surrounded by an electrically conductive material.

2. The mutual capacitance touchscreen of claim 1, wherein the first and second sets of traces form a plurality of substantially rectilinear, rectangular or square cells in each of the rows and columns.

3. The mutual capacitance touchscreen of claim 1, wherein each cell comprises a plurality of diamond-shaped sub-cells.

4. The mutual capacitance touchscreen of claim 1, wherein the first and second sets of traces form a sensor array comprising a plurality of cells, the array having corners and edges, cells located at the corners and edges of the array having reduced width or length with respect to cells not located at the corners and edges.

5. The mutual capacitance touchscreen of claim 1, wherein the angle is about 90 degrees.

6. The mutual capacitance touchscreen of claim 1, wherein the first and second sets of electrically conductive traces are disposed in substantially parallel but vertically-offset first and second planes, respectively.

7. The mutual capacitance touchscreen of claim 1, wherein each of the gaps has a width ranging between about 100 microns and about 300 microns.

8. The mutual capacitance touchscreen of claim 1, wherein the first or second set of electrically conductive traces further comprises a substantially solid pattern.

9. The mutual capacitance touchscreen of claim 1, wherein the first or second set of electrically conductive traces comprises indium tin oxide (“

ITO”

).

10. The mutual capacitance touchscreen of claim 1, wherein the first and second sets of electrically conductive traces form a 9×

16 sensor array or an 8×

12 sensor array.

11. The mutual capacitance touchscreen of claim 1, wherein the first and second sets of electrically conductive traces form an array of cells, where each cell forms a rectangle or square having sides ranging between about 3 mm and about 7 mm in length.

12. The mutual capacitance touchscreen of claim 1, wherein the first and second cross-over traces have widths ranging between about 40 microns and about 140 microns.

13. The mutual capacitance touchscreen of claim 1, wherein each cell further comprises at least one sub-cell diamond-shaped drive electrode extending outside such cell to a neighboring cell, and at least one sub-cell diamond-shaped sense electrode extending outside such cell to another neighboring cell, the at least one sub-cell diamond-shaped drive electrode and the at least one sub-cell diamond-shaped sense electrode being electrically connected to other diamond-shaped sub-cell drive and sense electrodes located within such cell.

14. The mutual capacitance touchscreen of claim 1, wherein a liquid crystal display is disposed therebeneath.

15. The mutual capacitance touchscreen of claim 1, wherein the first and second sets of electrically conductive traces are disposed on a substrate comprising an electrically insulative material.

16. The mutual capacitance touchscreen of claim 15, wherein the substrate is substantially optically transparent.

17. The mutual capacitance touchscreen of claim 1, further comprising a drive signal circuit operably connected to the first or second sets of electrically conductive traces and configured to provide an electrical drive signal thereto.

18. The mutual capacitance touchscreen of claim 1, further comprising a capacitance sensing circuit operably coupled to the first or second sets of electrically conductive traces and configured to detect changes in capacitance occurring in the vicinity thereof.

19. The mutual capacitance touchscreen of claim 17 or 18, wherein at least one of the drive signal circuit and the capacitance sensing circuit is incorporated into an integrated circuit.

20. The mutual capacitance touchscreen of claim 1, wherein the touchscreen is incorporated into or forms a portion of an LCD, a computer display, a laptop computer, a personal data assistant (PDA), a mobile telephone, a radio, an MP3 player, a portable music player, a stationary device, a television, a stereo, an exercise machine, an industrial control, a control panel, an outdoor control device and a household appliance.