Capacitive Touch-on-Surface Input Apparatus With Touch-Force Sensing Using Profiled Capacitive Electrode

Patent metadata

Field	Value
Publication number	US-2017185186-A1
Application number	US-201615391497-A
Country	US
Kind code	A1
Filing date	Dec 27, 2016
Priority date	Dec 27, 2015
Publication date	Jun 29, 2017
Grant date	—

Abstract

A device (such as for mobile communications) including a capacitive touch-on-surface (ToS) display adapted for capacitive touch-force sensing. A ToS capacitive sensor includes a profiled capacitive sensor electrode, intermediate and spaced from parallel ground plates by elastomeric insulator/dielectric spacer elements. The profiled capacitive sensor electrode has a non-uniform density profile that is relatively lower near a center of the electrode, and relatively higher near edges of the electrode, for example, equalizing touch-force sensitivity such that sensitivity to a touch-force deflection is substantially uniform across the profiled capacitive electrode. Capacitive sensor electronics coupled to the profiled capacitive sensor electrode measures a touch-force deflection of the ToS display panel based on a resulting touch-force deflection of the profiled capacitive electrode, such that the combined distance between the profiled capacitive sensor electrode and the ground electrodes is reduced by compression of the elastomeric spacer elements.

First claim

1 . A device including a touch-on-surface (ToS) display panel adapted for capacitive touch-force (Z) sensing, comprising:
a device case; a capacitive ToS display panel supported around the edges by the device case; and a ToS capacitive sensor assembly disposed adjacent the ToS display panel, including
a profiled capacitive sensor electrode plate,
two ground plates coupled to ground,
the profiled capacitive sensor electrode plate and the ground plates in a parallel plan arrangement with the capacitive sensor electrode plate spaced from the ground plates by respective elastomeric insulator spacer elements; and
the profiled capacitive sensor electrode configured with a density profile that is relatively lower near a center of the electrode, and relatively higher near the edges of the electrode.

2 . The device of claim 1 , wherein the profiled capacitive sensor electrode is configured with a density profile such that sensitivity to a touch-force (Z) deflection of the profiled capacitive sensor electrode is substantially uniform across the electrode.

3 . The device of claim 1 , further comprising capacitive sensor electronics coupled to the profiled capacitive sensor electrode to measure a touch-force deflection (Z) of the ToS display panel based on a resulting touch-force (Z) deflection of the profiled capacitive electrode relative to the ground electrodes.

4 . The device of claim 3 , wherein the capacitive sensor electronics measures touch-force deflection (Z) of the ToS display panel based on a change in capacitance of the profiled capacitive sensor electrode.

5 . The device of claim 1 , wherein a touch press of the ToS display surface causes a corresponding deflection of the profiled capacitive sensor electrode and the ground electrodes such that combined distance between the capacitive sensor electrode and the ground electrodes is reduced by compression of the elastomeric spacer elements.

6 . An ToS capacitive sensor assembly suitable for use in a device including a touch-on-surface (ToS) display panel, comprising:
a profiled capacitive sensor electrode plate, disposed intermediate two ground plates coupled to ground, the profiled capacitive sensor plate and the ground plates configured in a parallel plane arrangement adjacent the ToS display panel, with the capacitive sensor electrode plate spaced from the ground plates by respective elastomeric insulator spacer elements, and the profiled capacitive sensor electrode configured with a density profile that is relatively lower near a center of the electrode, and relatively higher near the edges of the electrode.

7 . The assembly of claim 6 , wherein the profiled capacitive sensor electrode is configured with a density profile such that sensitivity to a touch-force (Z) deflection of the profiled capacitive sensor electrode is substantially uniform across the electrode.

8 . The assembly of claim 6 , further comprising capacitive sensor electronics coupled to the profiled capacitive sensor electrode to measure touch-force deflection (Z) of the ToS display panel based on a corresponding touch-force deflection (Z) of the profiled capacitive sensor electrode relative to the ground electrodes.

9 . The assembly of claim 8 , wherein the capacitive sensor electronics measures touch-force deflection (Z) of the ToS display panel based on a change in capacitance of the profiled capacitive sensor electrode.

10 . The assembly of claim 6 , wherein a touch press of the ToS display surface causes a corresponding deflection of the profiled capacitive sensor electrode and the ground electrodes such that combined distance between the capacitive sensor electrode and the ground electrodes is reduced by compression of the elastomeric spacer elements.

11 . A method suitable for measuring a touch-force (Z) deflection of a touch-on-surface (ToS) display panel based on capacitive touch-force (Z) sensing, comprising:
disposing a ToS capacitive sensor assembly adjacent the ToS display panel, the ToS capacitive sensor assembly including a profiled capacitive sensor electrode plate disposed intermediate two ground plates coupled to ground in a parallel plate arrangement, with the capacitive sensor electrode plate spaced from the ground plates by respective elastomeric insulator spacer elements; configuring the profiled capacitive sensor electrode with a density profile that is relatively lower near a center of the electrode, and relatively higher near the edges of the electrode; and measuring a touch-force deflection (Z) of the ToS display panel based on a resulting touch-force (Z) deflection of the profiled capacitive electrode relative to the ground electrodes.

12 . The method of claim 11 , wherein the profiled capacitive sensor electrode is configured with a density profile such that sensitivity to a touch-force (Z) deflection of the profiled capacitive sensor electrode is substantially uniform across the electrode.

13 . The method of claim 11 , wherein touch-force deflection (Z) of the ToS display panel is measured based on a change in capacitance of the profiled capacitive sensor electrode.

14 . The method of claim 11 , wherein a touch-force deflection (Z) of the ToS display surface causes a corresponding deflection of the profiled capacitive sensor electrode and the ground electrodes, such that combined distance between the capacitive sensor electrode and the ground electrodes is reduced by compression of the elastomeric spacer elements.

Assignees

• Texas Instruments Inc

Inventors

• Liu Dongtai

Classifications

• G06F2203/04106

  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 title

• G06F2203/04105

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

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/0447 Primary

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