Capacitive touch panel with force sensing

Patent metadata

Field	Value
Publication number	US-9182859-B2
Application number	US-201213597950-A
Country	US
Kind code	B2
Filing date	Aug 29, 2012
Priority date	Aug 29, 2012
Publication date	Nov 10, 2015
Grant date	Nov 10, 2015

Abstract

A capacitive type touch sensing device includes a first electrode array including a plurality of drive electrodes and a plurality of sense electrodes, and a second electrode array spaced apart from the first electrode array and including a plurality of discrete, electrically floating conductive regions. At least part of the second electrode array positionally overlaps with at least part of the first electrode array to define a separation distance therebetween, the separation distance varying with a force applied to a surface of the touch sensing device. Further, each conductive region is positioned relative to a respective drive electrode and sense electrode of the first electrode array so that a capacitance between certain pairs of drive and sense electrodes is more sensitive to a variation in the separation distance than a capacitance between other pairs of drive and sense electrodes.

First claim

What is claimed is:

1. A capacitive type touch sensing device, comprising:
a first electrode array of electrode elements formed on a substrate, each electrode element including a drive electrode portion and a sense electrode portion; and
a second electrode array spaced apart from the first electrode array and including a plurality of discrete, electrically floating conductive regions,
wherein at least part of the second electrode array positionally overlaps with at least part of the first electrode array to define a separation distance therebetween, the separation distance varying with a force applied to a surface of the touch sensing device, and at least one of the drive electrode portion or the sense electrode portion of each electrode element is symmetrically divided into a pair of electrode sections, and
wherein each electrically floating conductive region is positioned relative to a respective electrode element of the first electrode array so that a capacitance between certain pairs of drive and sense electrode sections is more sensitive to a variation in the separation distance than a capacitance between other pairs of drive and sense electrode sections.

2. The touch sensing device according to claim 1 , further comprising:
a first substrate including a first electrode layer;
a second substrate including a second electrode layer; and
a deformable medium arranged between the first substrate and the second substrate, wherein the drive electrodes and the sense electrodes are formed in the first electrode layer and the electrically floating conductive regions are formed in the second electrode layer.

3. The touch sensing device according to claim 2 , wherein the first electrode layer and the second electrode layer are formed from a transparent conductive material.

4. The touch sensing device according to claim 2 , wherein the second electrode layer is formed from a transparent film of semiconductor material.

5. The touch sensing device according to claim 2 , wherein the drive electrodes, the sense electrodes, and the second electrode layer are formed from a network of metal tracks.

6. The touch sensing device according to claim 1 , wherein the drive electrodes are patterned into a series of interconnecting diamond shapes in a first direction, and the sense electrodes are patterned into a series of interconnecting diamond shapes in a second direction.

7. The touch sensing device according to claim 6 , wherein the first direction is orthogonal to the second direction.

8. The touch sensing device according to claim 1 , wherein the drive electrodes tessellate with the sense electrodes.

9. The touch sensing device according to claim 1 , wherein the electrically floating conductive regions are positioned to at least partially overlap with the drive electrodes, at least partially overlap with odd numbered sense electrodes, and not overlap with even numbered sense electrodes.

10. The touch sensing device according to claim 1 , wherein the pairs of the electrode sections include a first sense electrode section and a second sense electrode section, and the electrically floating conductive regions are arranged to at least partially overlap with the drive electrodes and the first sense electrode section, and not overlap with the second sense electrode section.

11. The touch sensing device according to claim 1 , wherein the pairs of the electrode sections include a first drive electrode section and a second drive electrode section,
the first drive electrode section does not positionally overlap with the electrically floating conductive regions, and
at least part of the second drive electrode section positionally overlaps with at least part of the electrically floating conductive regions.

12. The touch sensing device according to claim 1 , wherein the sense electrodes are divided into two sections that share a common geometric centroid.

13. The touch sensing device according to claim 12 , wherein each sense electrode is divided into a first ring section and a second center section, the first ring section arranged symmetrically around the second center section.

14. The touch sensing device according to claim 13 , wherein the electrically floating conductive regions are patterned to at least partially overlap the drive electrodes and the first ring section, and not overlap the second center section.

15. The touch sensing device according to claim 13 , where the electrically floating conductive regions overlap the entire drive electrode.

16. The touch sensing device according to claim 13 , wherein the electrically floating conductive regions are arranged to at least partially overlap the drive electrodes and the second center section.

17. The touch sensing device according to claim 1 , further comprising circuitry operatively coupled to the drive electrodes and the sense electrodes, the circuitry configured to:
determine a location on the touch sensing device at which an object touches a surface of the touch sensing device; and
determine a force applied at the determined location.

18. The touch sensing device according to claim 17 , wherein the circuitry comprises a processor configured to:
sequentially apply a stimulus signal to each drive electrode;
sequentially connect each sense electrode to measurement circuitry to measure a signal on each sense electrode, said signal generated in response to an object touching a surface of the touch sensing device and creating capacitive coupling between a stimulated drive electrode and a connected sense electrode; and
calculate a location of the object touching the surface and a force applied at the location based on the signal measured from each sense electrode.

Assignees

• Coulson Michael Paul
• Brown Christopher James
• Slamkul Dauren
• Sharp Kk

Inventors

• Coulson Michael Paul
• Brown Christopher James
• Slamkul Dauren

Classifications

• G06F2203/04105

  Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position · CPC title

• G06F3/0414

  using force sensing means to determine a position · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/0447 Primary

  Position sensing using the local deformation of sensor cells · CPC title

• G06F3/0445

  using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer · CPC title