Pressure sensor and pressure detecting method

Patent metadata

Field	Value
Publication number	US-11320678-B2
Application number	US-201816329506-A
Country	US
Kind code	B2
Filing date	Jul 24, 2018
Priority date	Sep 7, 2017
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

A pressure sensor and a pressure detecting method are provided, the pressure sensor includes a liquid crystal cell including a cholesteric liquid crystal layer, a liquid crystal state detector module and a pressure finder module, and the liquid crystal cell includes a pressure receiving surface. The liquid crystal state detector module is configured to detect a liquid crystal arrangement state in the cholesteric liquid crystal layer in a situation where a pressure is applied on the pressure receiving surface of the liquid crystal cell; the pressure finder module is configured to find a value of the pressure corresponding to the liquid crystal arrangement state from a pre-stored correspondence table.

First claim

What is claimed is:

1. A pressure sensor, comprising: a liquid crystal cell comprising a first substrate and a second substrate which are opposite to each other, a cholesteric liquid crystal layer between the first substrate and the second substrate, a horizontally-oriented alignment layer between the cholesteric liquid crystal layer and the first substrate, and another horizontally-oriented alignment layer between the cholesteric liquid crystal layer and the second substrate; a liquid crystal state detector module and a pressure finder module, wherein
the liquid crystal cell comprises a pressure receiving surface;
the liquid crystal state detector module is configured to detect a liquid crystal arrangement state in the cholesteric liquid crystal layer in a situation where a pressure is applied on the pressure receiving surface of the liquid crystal cell; and
the pressure finder module is configured to find a value of the pressure corresponding to the liquid crystal arrangement state from a pre-stored correspondence table.

2. The pressure sensor according to claim 1 , wherein
the liquid crystal state detector module comprises a light transmittance detector unit;
the light transmittance detector unit is configured to detect a light transmittance of the cholesteric liquid crystal layer, and the light transmittance that is detected represents the liquid crystal arrangement state in the cholesteric liquid crystal layer;
the pressure finder module comprises a first finder unit;
the first finder unit is configured to find the pressure corresponding to the light transmittance from a first correspondence table, and the first correspondence table stores different light transmittances and pressure values corresponding to the light transmittances.

3. The pressure sensor according to claim 2 , wherein
the light transmittance detector unit comprises a first light source, a first light intensity detector subunit and a light transmittance calculator subunit;
the first light source is at a side of the liquid crystal cell and is configured to emit light having a predetermined light-intensity to the liquid crystal cell;
the first light intensity detector subunit is at a side of the cholesteric liquid crystal layer facing away from the first light source, and the first light intensity detector subunit is configured to detect a transmitted-light intensity at the side of the cholesteric liquid crystal layer facing away from the first light source;
the light transmittance calculator subunit is configured to calculate the light transmittance of the cholesteric liquid crystal layer according to the transmitted-light intensity and the predetermined light-intensity, and the light transmittance of the cholesteric liquid crystal layer is equal to a ratio of the transmitted-light intensity to the predetermined light-intensity.

4. The pressure sensor according to claim 3 , wherein
the first light intensity detector subunit comprises a first photoelectric conversion layer and a first data processor;
the first photoelectric conversion layer is coupled to the liquid crystal cell and is configured to generate an electrical signal according to light transmitted to the side of the cholesteric liquid crystal layer facing away from the first light source, and to output the electrical signal to the first data processor;
the first data processor is connected with the first photoelectric conversion layer and is configured to process the electrical signal output by the first photoelectric conversion layer to obtain the transmitted-light intensity corresponding to the electrical signal.

5. The pressure sensor according to claim 2 , wherein
light transmittance detector unit comprises a first light intensity detector subunit, a second light intensity detector subunit and a light transmittance calculator subunit;
the second light intensity detector subunit is at a side of the cholesteric liquid crystal layer facing an ambient light source, and the second light intensity detector subunit is configured to detect an incident-light intensity at the side of the cholesteric liquid crystal layer facing the ambient light source;
the first light intensity detector subunit is at a side of the cholesteric liquid crystal layer facing away from the second light intensity detector submit, and the first light intensity detector subunit is configured to detect a transmitted-light intensity at the side of the cholesteric liquid crystal layer facing away from the second light intensity detector submit;
the light transmittance calculator subunit is configured to calculate the light transmittance of the cholesteric liquid crystal layer according to the transmitted-light intensity and the incident-light intensity, and the light transmittance of the cholesteric liquid crystal layer is equal to a ratio of the transmitted-light intensity to the incident-light intensity.

6. The pressure sensor according to claim 5 , wherein
the first light intensity detector subunit comprises a first photoelectric conversion layer and a first data processor;
the first photoelectric conversion layer is coupled to the liquid crystal cell and is configured to generate an electrical signal according to light transmitted to the side of the cholesteric liquid crystal layer facing away from the ambient source, and to output the electrical signal to the first data processor;
the first data processor is connected with the first photoelectric conversion layer and is configured to process the electrical signal output by the first photoelectric conversion layer to obtain the transmitted-light intensity corresponding to the electrical signal;
the second light intensity detector subunit comprises a second photoelectric conversion layer and a second data processor;
the second photoelectric conversion layer is coupled to the liquid crystal cell and is configured to generate another electrical signal according to light incident at the side of the cholesteric liquid crystal layer facing the ambient source, and to output the another electrical signal to the second data processor;
the second data processor is connected with the second photoelectric conversion layer and is configured to process the another electrical signal output by the second photoelectric conversion layer to obtain the incident-light intensity corresponding to the another electrical signal.

7. The pressure sensor according to claim 1 , wherein
the liquid crystal state detector module comprises a spectrum detector unit;
the spectrum detector unit is configured to detect a spectrum of light reflected by the cholesteric liquid crystal layer, and the spectrum that is detected represents the liquid crystal arrangement state in the cholesteric liquid crystal layer;
the pressure finder module comprises a second finder unit;
the second finder unit is configured to find the pressure corresponding to the spectrum from a second correspondence table, and the second correspondence table stores different spectrums and pressure values corresponding to the spectrums.

8. The pressure sensor according to claim 7 , wherein
the spectrum detector unit comprises a spectrum detector;
the spectrum detector is at a side of the liquid crystal cell and is configured to detect the spectrum of reflected light formed by natural light that is reflected by the cholesteric liquid crystal layer.

9. The pressure sensor according to claim 1 , wherein
the liquid crystal cell comprises a first substrate and a second substrate which are opposite to each other, the cholesteric liquid crystal layer is between the first substrate and the second substrate, a horizontally-oriented alignment layer is between the cholesteric liquid crystal layer and the first substrate, and another ho

Assignees

• Beijing Boe Optoelectronics Tech Co Ltd
• Boe Technology Group Co Ltd

Inventors

• Wang Ying
• Ting Tien Lun
• Cao Xue
• Che Chuncheng
• Xue Hailin
• Shao Xibin
• Cai Peizhi

Classifications

• G02F1/0072 Primary

  Mechanical, acoustic, electro-elastic, magneto-elastic properties · CPC title

• G01L11/02

  by optical means · CPC title

• G02F1/1309 Primary

  Repairing; Testing · CPC title

• G01L1/247

  using distributed sensing elements, e.g. microcapsules (along a single optical fibre G01L1/242) · CPC title

• G02F1/13718

  based on a change of the texture state of a cholesteric liquid crystal · CPC title