Capacitive touch panel with a ‘dual layer’ force sensor

• US 9,158,407 B2
• Filed: 08/29/2012
• Issued: 10/13/2015
• Est. Priority Date: 08/29/2012
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Coulson, Michael Paul, Brown, Christopher James, Slamkul, Dauren
• Primary Examiner(s): HARRIS, DOROTHY H
• Application Number:
  US13/597,925
• Publication Number:
  US 20140062933A1
• Time in Patent Office: 1,140 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A capacitive touch panel includes a first substrate and a second substrate arranged relative to the first substrate. A plurality of drive electrodes are arranged on the first substrate, wherein each drive electrode comprises a first drive electrode section and a second drive electrode section. In addition, a plurality of sense electrodes are arranged on the second substrate, the plurality of sense electrodes including touch sensing electrodes and force sensing electrodes. At least part of a sense electrode of the plurality of sense electrodes forms a force sensitive coupling capacitance with a second drive electrode section and not with a first drive electrode section.

Claims

1. A capacitive touch panel, comprising:

a plurality of drive electrodes arranged in a first direction, each drive electrode including a first drive electrode section and a second drive electrode section; and

a plurality of sense electrodes arranged in a second direction, each sense electrode including a touch sensing electrode and a force sensing electrode,

wherein each force sensing electrode of the plurality of sense electrodes is arranged relative to a drive electrode of the plurality of drive electrodes to form a force sensitive coupling capacitance with the second drive electrode section of the respective drive electrode and substantially not with the first drive electrode section of the respective drive electrode,

wherein for a sensor location the first drive electrode section of each drive electrode does not positionally overlap with a touch sensing electrode or a force sensing electrode.

2. The touch panel according to claim 1, wherein the plurality of touch sensing electrodes do not positionally overlap with a drive electrode of the plurality of drive electrodes.

3. The touch panel according to claim 1, further comprising:

a first substrate having a first conductive layer; and

a second substrate having a second conductive layer, wherein the plurality of drive electrodes are formed in the first conductive layer, and the plurality of sense electrodes are formed in the second conductive layer.

4. The touch panel according to claim 3, wherein the second drive electrode section of a drive electrode, in a plane of the first or second substrate, is further from a touch sensing electrode than the first drive electrode section of the respective drive electrode.

5. The touch panel according to claim 4, further comprising a deformable layer arranged between the first substrate and the second substrate.

6. The touch panel according to claim 1, wherein the force sensing electrode is arranged to form a parallel plate capacitor with a corresponding second drive electrode section.

7. The touch panel according to claim 1, wherein the force sensing electrode is smaller in size than the second drive electrode section.

8. The touch panel according to claim 1, wherein the plurality of drive electrodes and the plurality of sense electrodes comprise a series of tessellating shapes.

9. The touch panel according to claim 8, wherein the force sensing electrodes are arranged parallel and adjacent to respective ones of the touch sensing electrodes.

10. The touch panel according to claim 1, wherein the force sensing electrode is arranged to positionally overlap with the second drive electrode section of a drive electrode, the force sensing electrode and respective second drive electrode section forming a parallel plate capacitor.

11. The touch panel according to claim 1, wherein at least one of the drive electrodes, the touch sensing electrodes or the force sensing electrodes are formed from a network of conductive tracks.

12. The touch panel according to claim 1, wherein the drive electrodes and sense electrodes are interdigitated.

13. The touch panel according to claim 1, wherein the force sensing electrodes are arranged symmetrically around the touch sensing electrodes.

14. The touch panel according to claim 1, wherein the force sensing electrodes are arranged such that for each sense electrode a geometric centroid of a force measurement location is coincident with a geometric centroid of a touch measurement location.

15. The touch panel according to claim 1, wherein each touch sensing electrode is split into a first touch sensing electrode section and a second touch sensing electrode section, and the first touch sensing electrode section forms at least a partial ring around the second touch electrode section.

16. The touch panel according to claim 1, wherein the touch sensing electrodes comprise a first touch sensing electrode section and a second touch sensing electrode section, and a majority of the area of the first touch sensing electrode section is closer to odd numbered drive electrode than the second touch sensing electrode section, and the majority of the area of the second touch sensing electrode section is closer to even numbered drive electrodes than the first touch sensing electrode section.

17. The touch panel according to claim 1, further comprising circuitry operatively coupled to the plurality of drive electrodes and the plurality of sense electrodes, the circuitry configured to:

determine a location on the touch panel at which an object touches the touch panel; and

determine a force applied at the determined location.

18. The touch panel according to claim 17, wherein the circuitry comprises a processor configured to:

sequentially apply a stimulus signal to each drive electrode;

measure a signal at the force sensing electrodes and touch sensing electrodes of each sense electrode, said signal in response to capacitive coupling between the drive electrodes and sense electrodes due to an object touching a surface of the touch panel; and

calculate a location and force of the object touching the surface of the touch panel based on the measured signal.

19. A capacitive touch panel, comprising:

a plurality of drive electrodes arranged in a first direction, each drive electrode including a first drive electrode section and a second drive electrode section; and

a plurality of sense electrodes arranged in a second direction, each sense electrode including a touch sensing electrode and a force sensing electrode,

wherein each force sensing electrode of the plurality of sense electrodes is arranged relative to a drive electrode of the plurality of drive electrodes to form a force sensitive coupling capacitance with the second drive electrode section of the respective drive electrode and substantially not with the first drive electrode section of the respective drive electrode, and

wherein the plurality of drive electrodes and the plurality of sense electrodes comprise a series of tessellating shapes having interconnecting diamond shapes, and each first drive electrode section of a drive electrode forms at least a partial ring around the second drive electrode section of the respective drive electrode.