Force detection apparatus and method, touch device and electronic terminal

Patent metadata

Field	Value
Publication number	US-10649570-B2
Application number	US-201715678110-A
Country	US
Kind code	B2
Filing date	Aug 16, 2017
Priority date	Jun 15, 2016
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Embodiments of the present disclosure provide a force detection apparatus and method, a touch device and an electronic terminal. The apparatus includes: a first detection capacitor, and a second detection capacitor configured to perform differential processing for a capacitance of the first detection capacitor to cancel an interference signal; wherein the first detection capacitor includes a force detection electrode, and the second detection capacitor includes a reference detection electrode, the force detection electrode and the reference detection electrode being arranged within a surface, such that the first detection capacitor and the second detection capacitor are simultaneously coupled to the interference signal causing interference to force detection, and differential processing is performed for capacitances of the first detection capacitor and the second detection capacitor. In this way, the interference signal, for example, which caused by a display device, is canceled, and sensitivity of force detection is enhanced while temperature drift is inhibited.

First claim

What is claimed is:

1. A force detection apparatus, comprising:
a differential circuit;
a first detection capacitor connected to the differential circuit; and
a second detection capacitor connected to the differential circuit and configured to perform differential processing for a capacitance of the first detection capacitor to cancel an interference signal;
wherein the first detection capacitor comprises a force detection electrode, and the second detection capacitor comprises a reference detection electrode, the force detection electrode and the reference detection electrode being arranged within a surface, such that the first detection capacitor and the second detection capacitor are simultaneously coupled to the interference signal causing interference to force detection, the capacitance of the first detection capacitor is greater than a capacitance of the second detection capacitor for force detection with an area of the reference detection electrode being less than an area of the force detection electrode, and
wherein the first detection capacitor is electrically connected to a first adjustable capacitor configured to adjust the capacitance of the first detection capacitor during force detection, and the first adjustable capacitor is grounded, and/or the second detection capacitor is electrically connected to a second adjustable capacitor configured to adjust capacitance of the second detection capacitor during force detection, and the second adjustable capacitor is grounded.

2. The apparatus according to claim 1 , wherein the force detection electrode is respectively coupled to a first conducting surface and a second conducting surface to form a first effective detection capacitor and a first load detection capacitor respectively; the first detection capacitor comprises the first effective detection capacitor and the first load detection capacitor, the first effective detection capacitor and the first load detection capacitor being connected in series; the reference detection electrode is respectively coupled to the first conducting surface and the second conductive surface to form a second effective detection capacitor and a second load detection capacitor respectively, the second effective detection capacitor and the second load detection capacitor being connected in series; and the second detection capacitor comprises the second effective detection capacitor and the second load detection capacitor.

3. The apparatus according to claim 2 , wherein the first conducting surface is a common reference electrode or a conductive back shell or a conductive middle frame of a terminal comprising the force detection apparatus; the second conducting surface is a conductive back shell or a conductive middle frame of a terminal comprising the force detection apparatus or a common reference electrode.

4. The apparatus according to claim 2 , wherein the first conducting surface and a display device of a terminal which comprises the force detection apparatus forms a first coupling capacitor, the display device and the second conducting surface forms a second coupling capacitor, and the first coupling capacitor and the second coupling capacitor have an identical capacitance during force detection; and the first coupling capacitor and the first detection capacitor are connected in series and the second coupling capacitor and the second detection capacitor are connected in series, such that the interference signal causing interference to force detection is coupled to both the first detection capacitor and the second detection capacitor.

5. The apparatus according to claim 1 , further comprising: a force driving electrode; wherein the force detection electrode is coupled to the force driving electrode to form a first effective mutual capacitor which is the first detection capacitor; and the reference detection electrode is coupled to the force driving electrode to form a second effective mutual capacitor which is the second detection capacitor.

6. The apparatus according to claim 1 , wherein the first detection capacitor is electrically connected to a first switch circuit such that the first detection capacitor is charged or discharged using the first switch circuit during force detection; and/or the second detection capacitor is electrically connected to a second switch circuit such that the second detection capacitor is charged or discharged using the second switch circuit during force inspection.

7. The apparatus according to claim 1 , wherein the differential circuit comprises a positive terminal and a negative terminal, and the first detection capacitor is electrically connected to the positive terminal and the second detection capacitor is electrically connected to the negative terminal to perform differential processing for the capacitances of the first detection capacitor and the second detection capacitor.

8. The apparatus according to claim 7 , wherein the positive terminal is electrically connected to a third switch circuit, the negative terminal is electrically connected to a fourth switch circuit, the first detection capacitor is electrically connected to the positive terminal via the third switch circuit, and the second detection capacitor is electrically connected to the negative terminal via the fourth switch circuit.

9. A force detection method, comprising:
detecting capacitances of a first detection capacitor comprising a force detection electrode and a second detection capacitor comprising a reference detection electrode, the first detection capacitor and the second detection capacitor being both connected to a differential circuit, wherein the force detection electrode and the reference detection electrode are arranged within a surface, such that the first detection capacitor and the second detection capacitor are simultaneously coupled to the interference signal causing interference to force detection, the capacitance of the first detection capacitor is greater than a capacitance of the second detection capacitor for force detection with an area of the reference detection electrode being less than an area of the force detection electrode; and
performing differential processing for the capacitances of the first detection capacitor and the second detection capacitor during force detection to cancel the interference signal to determine a force value,
wherein the first detection capacitor is electrically connected to a first adjustable capacitor configured to adjust the capacitance of the first detection capacitor during force detection, and the first adjustable capacitor is grounded, and/or the second detection capacitor is electrically connected to a second adjustable capacitor configured to adjust capacitance of the second detection capacitor during force detection, and the second adjustable capacitor is grounded.

10. The method according to claim 9 , wherein the detecting capacitances of a first detection capacitor comprising a force detection electrode and a second detection capacitor comprising a reference detection electrode comprises:
detecting capacitances of a first effective detection capacitor and a first load detection capacitor that are formed by coupling of a first conducting surface and a second conducting surface, wherein the first detection capacitor comprises the first effective detection capacitor and the first load detection capacitor, the first effective detection capacitor and the first load detection capacitor are connected in series; and
detecting capacitances of a second effective detection capacitor and a second load detection capacitor that are formed by coupling of the first conducting surface and the second conducting surface, wherein the second detection capacitor comprises the second effective

Assignees

• Shenzhen Goodix Tech Co Ltd

Inventors

• Jiang Hong
• Yang Mengta
• Yang Fuchiang

Classifications

• G06F3/0414 Primary

  using force sensing means to determine a position · CPC title

• G06F3/04883

  for inputting data by handwriting, e.g. gesture or text · CPC title

• G01L1/144

  with associated circuitry (G01L1/146 and G01L1/148 take precedence) · CPC title

• G06F3/0412

  Digitisers structurally integrated in a display · CPC title

• G06F3/044

  by capacitive means · CPC title