Pressure detection chip and method for detection pressure

Patent metadata

Field	Value
Publication number	US-11099092-B2
Application number	US-201916449375-A
Country	US
Kind code	B2
Filing date	Jun 22, 2019
Priority date	Mar 12, 2018
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A pressure detection chip and a method for detection pressure are disclosed. The method is executed by a pressure detection apparatus including a cancellation circuit and a coupling circuit in parallel; the coupling circuit includes a variable capacitance component having a first electrode layer and a second electrode layer. The method for detection pressure includes: inputting a first input signal to the cancellation circuit and outputting a first output signal; and inputting a second input signal to the coupling circuit and outputting a second input signal, where the first input signal and the second input signal are 180 degrees out of phase, and the first output signal is configured to cancel the second output signal; and determining whether the first electrode layer is subjected to the touch pressure, according to the first output signal and the second output signal.

First claim

What is claimed is:

1. A pressure detection apparatus, comprising: a pressure detection chip and a first coupling circuit, wherein:
the pressure detection chip comprises a first cancellation circuit, a driving unit, and a processing unit,
the first cancellation circuit is connected in parallel with the first coupling circuit, the first coupling circuit comprises a variable capacitance component; the variable capacitance component comprises a first electrode layer and a second electrode layer, a distance between the first electrode layer and the second electrode layer changes when the first electrode layer is subjected to a touch pressure, a capacitance value of the variable capacitance component changes with a change of the distance between the first electrode layer and the second electrode layer;
the driving unit is configured to output a first input signal to the first cancellation circuit, and output a second input signal to the first coupling circuit;
the first cancellation circuit is configured to receive the first input signal and output a first output signal;
the first coupling circuit is configured to receive the second input signal and output a second output signal, wherein the first input signal and the second input signal are 180 degrees out of phase, and the first output signal is configured to cancel the second output signal; and
the processing unit is configured to determine whether the first electrode layer is subjected to the touch pressure according to the first output signal and the second output signal;
wherein the processing unit is configured to:
determine the first electrode layer is not subjected to the touch pressure if a difference signal between the first input signal and the second output signal is less than or equal to a first preset value; or
determine the first electrode layer is subjected to the touch pressure if the difference signal between the first input signal and the second output signal is greater than the first preset value.

2. The pressure detection apparatus according to claim 1 , wherein the first cancellation circuit comprises a preset capacitor; capacitance of the preset capacitor is equal to initial capacitance of the variable capacitance component; and the initial capacitance is equivalent capacitance between the first electrode layer and the second electrode layer when the first electrode layer is not subjected to the touch pressure.

3. The pressure detection apparatus according to claim 2 , wherein the pressure detection chip further comprises: an amplifying circuit; both an output end of the first cancellation circuit and an output end of the first coupling circuit connect to an input end of the amplifying circuit; and the amplifying circuit is configured to amplify the first output signal and the second output signal.

4. The pressure detection apparatus according to claim 3 , wherein the first input signal is obtained by inverting a phase of the second input signal by 180 degrees.

5. The pressure detection apparatus according to claim 1 , wherein the pressure detection chip further comprises: an amplifying circuit; both an output end of the first cancellation circuit and an output end of the first coupling circuit connect to an input end of the amplifying circuit; and the amplifying circuit is configured to amplify the first output signal and the second output signal.

6. The pressure detection apparatus according to claim 1 , wherein the first input signal is obtained by inverting a phase of the second input signal by 180 degrees.

7. The pressure detection apparatus according to claim 1 , wherein the processing unit is configured to:
determine a pressure characteristic of the touch pressure, if it determines that the first electrode layer is subjected to the touch pressure, wherein the pressure characteristic comprises magnitude of the touch pressure duration of the touch pressure.

8. A pressure detection apparatus, comprising: a pressure detection chip and a first coupling circuit, wherein:
the pressure detection chip comprises a first cancellation circuit, a driving unit, and a processing unit,
the first cancellation circuit is connected in parallel with the first coupling circuit, the first coupling circuit comprises a variable capacitance component the variable capacitance component comprises a first electrode layer and a second electrode layer, a distance between the first electrode layer and the second electrode layer changes when the first electrode layer is subjected to a touch pressure, a capacitance value of the variable capacitance component changes with a change of the distance between the first electrode layer and the second electrode layer;
the driving unit is configured to output a first input signal to the first cancellation circuit, and output a second input signal to the first coupling circuit;
the first cancellation circuit is configured to receive the first input signal and output a first output signal;
the first coupling circuit is configured to receive the second input signal and output a second output signal, wherein the first input signal and the second input signal are 180 degrees out of phase, and the first output signal is configured to cancel the second output signal; and
the processing unit is configured to determine whether the first electrode layer is subjected to the touch pressure according to the first output signal and the second output signal;
wherein the pressure detection chip further comprises a second cancellation circuit the pressure detection apparatus further comprises a second coupling circuit the second cancellation circuit is connected in parallel with the second coupling circuit an input signal of the second cancellation circuit and an input signal of the second coupling circuit are 180 degrees out of phase; and an output signal of the second cancellation circuit is configured to cancel an output signal of the second coupling circuit;
wherein a difference signal between the first output signal and the second output signal is a first difference signal, a different signal between the output signal of the second cancellation circuit and the output signal of the second coupling circuit is a second difference signal, and the first difference signal is greater than or equal to the second difference signal;
the processing unit is configured to:
determine the first electrode layer is not subjected to the touch pressure if the first difference signal is greater than a first preset value, and a difference signal between the first different signal and the second different signal is less than or equal to a second preset value; or
determine the first electrode layer is subjected to the touch pressure if the first difference signal is greater than the first preset value, and the difference signal between the first difference signal and the second difference signal is greater than the second preset value.

9. The pressure detection apparatus according to claim 8 , wherein the first cancellation circuit comprises a preset capacitor; capacitance of the preset capacitor is equal to initial capacitance of the variable capacitance component; and the initial capacitance is equivalent capacitance between the first electrode layer and the second electrode layer when the first electrode layer is not subjected to the touch pressure.

10. The pressure detection apparatus according to claim 8 , wherein the pressure detection chip further comprises: an amplifying circuit; both an output end of the first cancellation circuit and an output end of the first coupling circuit connect to an input end of the amplifying circuit; and the amplifying circuit is configured to amplify the first output signal and the second output signal.

Assignees

• Shenzhen Goodix Tech Co Ltd

Inventors

• Wei Haijun
• Chen Tujiang

Classifications

• G06F3/041

  Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means · CPC title

• G01L1/26 Primary

  Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload · CPC title

• G06F3/0447

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

• 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