Method for detecting pressure of active pen, device and active pen

Patent metadata

Field	Value
Publication number	US-10955940-B2
Application number	US-201916457790-A
Country	US
Kind code	B2
Filing date	Jun 28, 2019
Priority date	Jan 5, 2018
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

Provided are a method for detecting a pressure of an active pen, a device and an active pen, where a pen body of the active pen is provided with a touch sensor. The method includes: obtaining a sensing change amount of the touch sensor, where the sensing change amount indicates a capacitance change amount of the touch sensor; and determining, according to the sensing change amount, a pressure value on the pen body. The technical solution provided by the disclosure can reduce the cost of the active pen while realizing the pressure detection for the active pen.

First claim

What is claimed is:

1. A method for detecting a pressure of an active pen, a pen body of the active pen being provided with a touch sensor, wherein the method comprises:
obtaining a sensing change amount of the touch sensor, wherein the sensing change amount is used to indicate a capacitance change amount of the touch sensor, and the sensing change amount is positively correlated with a contact area between the pen body and a hand;
determining, according to the sensing change amount, a pressure value received by the pen body; and
transmitting the pressure value to a touch terminal, via a wire or wirelessly, to enable the touch terminal to display a thickness of a handwriting according to the pressure value.

2. The method according to claim 1 , wherein the obtaining a sensing change amount of the touch sensor comprises:
obtaining a reference sensing value of the touch sensor, wherein the reference sensing value is amplitude of a voltage signal fed back by the touch sensor in response to a reference voltage signal applied thereon when the pen body is free of pressure;
obtaining a current sensing value of the touch sensor, wherein the current sensing value is amplitude of a voltage signal fed back by the touch sensor in response to the reference voltage signal applied thereon at a current time; and
obtaining a difference between the reference sensing value and the current sensing value as the sensing change amount of the touch sensor.

3. The method according to claim 2 , wherein the obtaining a reference sensing value of the touch sensor comprises:
obtaining a pre-stored reference sensing value of the touch sensor.

4. The method according to claim 3 , wherein the method further comprises:
updating the pre-stored reference sensing value of the touch sensor when the active pen is powered on or sleeping,
wherein the updating the pre-stored reference sensing value of the touch sensor comprises:
obtaining the current sensing value of the touch sensor; and
updating the pre-stored reference sensing value of the touch sensor with the current sensing value when an absolute value of a difference between the current sensing value and the pre-stored reference sensing value is smaller than a preset sensing threshold.

5. The method according to claim 2 , wherein there are a plurality of touch sensors, and the obtaining the current sensing value of the touch sensor comprises:
scanning each of the touch sensors sequentially using the reference voltage signal, and obtaining amplitude of a voltage signal fed back by each of the touch sensors.

6. An active pen, comprising a pen body and a nib, wherein the pen body is provided with a touch sensor, and the active pen further comprises: a memory and a processor, wherein:
the memory is configured to store executable instructions; and
the processor is configured to implement the method according to claim 1 when executing the executable instructions.

7. The active pen according to claim 6 , wherein there are a plurality of touch sensors, and the plurality of the touch sensors are located at an end of the pen body near the nib, and are axially spaced along the pen body,
wherein each of the touch sensor is a ring electrode, the ring electrode being disposed coaxially with the pen body.

8. The active pen according to claim 6 , wherein the active pen further comprises: a radio circuit, wherein the radio circuit is electrically connected to the processor, and configured to transmit the pressure value to a touch terminal wirelessly according to an instruction of the processor.

9. A touch input system, comprising: a touch terminal and the active pen according to claim 6 .

10. The method according to claim 1 , wherein there are a plurality of touch sensors, and the obtaining a sensing change amount of the touch sensor comprises:
obtaining the sensing change amount of each of the touch sensors separately,
wherein the determining, according to the sensing change amount, a pressure value received by the pen body comprises:
calculating a sum of sensing change amounts of the touch sensors;
determining whether the sum of the sensing change amounts is greater than zero; and
determining the pressure value on the pen body according to the sensing change amounts and a preset mapping relationship if the sum of the sensing change amounts is greater than zero, wherein the mapping relationship comprises mapping information between the pressure value and the sensing change amounts of the touch sensors.

11. The method according to claim 1 , wherein the method further comprises:
controlling the active pen to enter a sleep-low-power state when a duration of the pressure value being smaller than a first pressure threshold is greater than a preset time threshold; and
waking up the active pen from the sleep-low-power state to a normal working state when the pressure value is greater than a second pressure threshold.

12. A device for detecting a pressure of an active pen, a pen body of the active pen being provided with a touch sensor, wherein the device comprises a processor configured to:
obtain a sensing change amount of the touch sensor, wherein the sensing change amount is used to indicate a capacitance change amount of the touch sensor, and the sensing change amount is positively correlated with a contact area between the pen body and a hand; and
determine, according to the sensing change amount obtained by the processor, a pressure value received by the pen body,
wherein the device further comprises:
a radio circuit, configured to transmit the pressure value determined by the processor to a touch terminal, via a wire or wirelessly, to enable the touch terminal to display a thickness of a handwriting according to the pressure value.

13. The device according to claim 12 , wherein the processor is further configured to:
obtain a reference sensing value of the touch sensor, wherein the reference sensing value is amplitude of a voltage signal fed back by the touch sensor in response to a reference voltage signal applied thereon when the pen body is free of pressure;
obtain a current sensing value of the touch sensor, wherein the current sensing value is amplitude of a voltage signal fed back by the touch sensor in response to the reference voltage signal applied thereon at a current time; and
obtain a difference between the reference sensing value obtained by the processor and the current sensing value obtained by the processor as the sensing change amount of the touch sensor.

14. The device according to claim 13 , wherein the device further comprises: a memory, configured to pre-store a reference sensing value of the touch sensor; and
the processor is further configured to:
obtain the reference sensing value of the touch sensor pre-stored in the memory.

15. The device according to claim 14 , wherein the processor is further configured to:
update the reference sensing value of the touch sensor pre-stored in the memory when the active pen is powered on or sleeping,
obtain the current sensing value of the touch sensor; and
update the reference sensing value of the touch sensor pre-stored in the memory with the current sensing value when an absolute value of the difference between the current sensing value obtained by the processor and the reference sensing value pre-stored in the memory is smaller than a preset sensing threshold.

16. The device according to claim 13 , wherein there are a plurality of touch sensors, and the processor is specifically further configured to:
scan each of the touch sensors sequentially using the reference voltage signal,

Assignees

• Shenzhen Goodix Tech Co Ltd
• Shenzhen Goodix Tech Go Ltd

Inventors

• Yin Hailin
• Yao Zhi
• Jin Wenhe
• Liu Yufeng

Classifications

• G06F3/03547

  Touch pads, in which fingers can move on a surface · CPC title

• G06F3/03545 Primary

  Pens or stylus · CPC title

• G06F3/0383

  Signal control means within the pointing device · CPC title

• G06F1/3296

  by lowering the supply or operating voltage · CPC title

• G06F2203/0384

  Wireless input, i.e. hardware and software details of wireless interface arrangements for pointing devices · CPC title