Pressure detection apparatus and intelligent terminal

Patent metadata

Field	Value
Publication number	US-10551977-B2
Application number	US-201715798075-A
Country	US
Kind code	B2
Filing date	Oct 30, 2017
Priority date	Sep 17, 2016
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A pressure detection apparatus includes: a drive power supply, a differential circuit, a pressure calculation unit, and at least one pressure sensor. Each pressure sensor includes a first electrode plate, a second electrode plate, a third electrode plate, a first elastic dielectric layer, and a second elastic dielectric layer. One detection capacitor is formed between the first electrode plate and the second electrode plate, and one detection capacitor is formed between the first electrode plate and the third electrode plate. The pressure sensor is connected between the drive power supply and an input terminal of the differential circuit, and an output terminal of the differential circuit is connected to the pressure calculation unit.

First claim

What is claimed is:

1. A pressure detection apparatus, comprising: a drive power supply, a differential circuit, a pressure calculation unit and at least one pressure sensor;
each pressure sensor comprises a first electrode plate, a second electrode plate, a third electrode plate, a first elastic dielectric layer and a second elastic dielectric layer; the first electrode plate is disposed between the second electrode plate and the third electrode plate; the first elastic dielectric layer is disposed between the first electrode plate and the second electrode plate; the second elastic dielectric layer is disposed between the first electrode plate and the third electrode plate; wherein, one detection capacitor is formed between the first electrode plate and the second electrode plate, and one detection capacitor is formed between the first electrode plate and the third electrode plate;
the pressure sensor is connected between the drive power supply and an input terminal of the differential circuit, and an output terminal of the differential circuit is connected to the pressure calculation unit;
the pressure sensor is configured to output two detection voltages across two terminals of each of the two detection capacitors when the first electrode plate is subject to an external pressure; the differential circuit is configured to output a voltage difference of the two detected voltages; and the pressure calculation unit is configured to calculate the pressure according to the voltage difference.

2. The pressure detection apparatus according to claim 1 , wherein the first electrode plate is connected to the drive power supply, and the second electrode plate and the third electrode plate are connected to the input terminal of the differential circuit respectively.

3. The pressure detection apparatus according to claim 1 , wherein the pressure detection apparatus further comprises: at least one charge switch and at least one discharge switch;
the first electrode plate is grounded; and
the second electrode plate and the third electrode plate are respectively connected to the drive power supply by using the charge switch, and are respectively connected to the input terminal of the differential circuit by using the discharge switch.

4. The pressure detection apparatus according to claim 3 , further comprising:
two charge switches, and the second electrode plate and the third electrode plate are respectively connected to the drive power supply by using the two charge switches; and/or
two discharge switches, and the second electrode plate and the third electrode plate are respectively connected to the input terminal of the differential circuit by using the two discharge switches; wherein
the two detection capacitors are charged when the charge switches are closed, and the two detection capacitors are discharged when the discharge switches are closed.

5. The pressure detection apparatus according to claim 3 , further comprising:
one charge switch and the charge switch is a double-pole double-throw switch; and/or
one discharge switch and the discharge switch is a double-pole double-throw switch, wherein the two detection capacitors are charged when the charge switch is closed, and the two detection capacitors are discharged when the discharge switch is closed.

6. The pressure detection apparatus according to claim 1 , wherein the pressure detection apparatus further comprises two adjustable capacitors; and
the two adjustable capacitors are connected in parallel to the two detection capacitors respectively, wherein the two adjustable capacitors are configured to adjust capacitance values of paths where each of the two detection capacitors locates, so that initial capacitance values of the paths where each of the two detection capacitors locates are equal when the first electrode plate is not subject to an external pressure.

7. The pressure detection apparatus according to claim 1 , further comprising initial capacitance values of paths where each of the two detection capacitors locates are unequal when the first electrode plate is not subject to an external pressure; and
the pressure detection apparatus further comprises an adjustable capacitor, wherein the adjustable capacitor is connected in parallel to a detection capacitor on a path having a smaller initial capacitance value, wherein the adjustable capacitor is configured to adjust a capacitance value of the path where the detection capacitor connected in parallel to the adjustable capacitor locates, so that the initial capacitance values of the paths where each of the two detection capacitors locates are equal when the first electrode plate is not subject to an external pressure.

8. The pressure detection apparatus according to claim 1 , further comprising multiple pressure sensors, and the pressure detection apparatus further comprises a switching unit; and
the multiple pressure sensors are switchably connected to the differential circuit by using the switching unit.

9. An intelligent terminal, comprising: a pressure detection apparatus, the pressure detection apparatus comprising: a drive power supply, a differential circuit, a pressure calculation unit and at least one pressure sensor;
each pressure sensor comprises a first electrode plate, a second electrode plate, a third electrode plate, a first elastic dielectric layer and a second elastic dielectric layer; the first electrode plate is disposed between the second electrode plate and the third electrode plate; the first elastic dielectric layer is disposed between the first electrode plate and the second electrode plate; the second elastic dielectric layer is disposed between the first electrode plate and the third electrode plate; wherein, one detection capacitor is formed between the first electrode plate and the second electrode plate, and one detection capacitor is formed between the first electrode plate and the third electrode plate;
the pressure sensor is connected between the drive power supply and an input terminal of the differential circuit, and an output terminal of the differential circuit is connected to the pressure calculation unit;
the pressure sensor is configured to output two detection voltages across two terminals of each of the two detection capacitors when the first electrode plate is subject to an external pressure; the differential circuit is configured to output a voltage difference of the two detected voltages; the pressure calculation unit is configured to calculate the pressure according to the voltage difference.

10. The intelligent terminal according to claim 9 , wherein: the intelligent terminal comprises an active stylus, and the active stylus further comprises a stylus housing, a stylus core and an insulating stylus cap;
the pressure detection apparatus is mounted in the stylus housing;
one end of the stylus core is fixed to the first electrode plate of the pressure sensor; and
the insulating stylus cap is sleeved over the other end of the stylus core with a preset distance between the insulating stylus cap and the housing, and the preset distance is greater than or equal to a maximum deformation distance of the first electrode plate, wherein if the insulating stylus cap is subject to an external pressure, the pressure is applied on the first electrode plate of the pressure sensor by means of the stylus core.

11. The intelligent terminal according to claim 9 , wherein the intelligent terminal comprises an apparatus with fingerprint recognition, and the apparatus with fingerprint recognition further comprises a fingerprint recognition module that is configured to recognize a fingerprint of a user, and a pressing element; and
one end of the pressing elemen

Assignees

• Shenzhen Goodix Tech Co Ltd

Inventors

• Jiang Hong
• Feng Lin
• Luo Zhongbo

Classifications

• G06F3/0488

  using a touch-screen or digitiser, e.g. input of commands through traced gestures · CPC title

• G06F3/03545

  Pens or stylus · CPC title

• G01L1/144

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

• G06F11/3058

  Monitoring arrangements for monitoring environmental properties or parameters of the computing system or of the computing system component, e.g. monitoring of power, currents, temperature, humidity, position, vibrations (thermal management in cooling arrangements of a computing system G06F1/206) · CPC title

• G06F11/3013

  where the computing system is an embedded system, i.e. a combination of hardware and software dedicated to perform a certain function in mobile devices, printers, automotive or aircraft systems (testing or monitoring of control systems or parts thereof G05B23/02) · CPC title