Resistive pressure sensor including piezo-resistive electrode

• US 9,645,028 B2
• Filed: 09/05/2014
• Issued: 05/09/2017
• Est. Priority Date: 09/05/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Bae, Jihyun, Lee, Byoungsun, Choong, Chwee Lin, Park, Jongjin, Im, Jungkyun
• Primary Examiner(s): Huber, Robert
• Assistant Examiner(s): Roberts, Herbert K
• Application Number:
  US14/478,755
• Publication Number:
  US 20150059486A1
• Time in Patent Office: 977 Days
• CPC Class Codes: G01L 1/2206 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
• CPC Class Codes: G01L 1/2293 of the semi-conductor type semi-conductor devices controllable by variations of applied mechanical force H01L29/84
• CPC Class Codes: G01L 2009/0069 the transducer being mounted on a flexible element
• CPC Class Codes: G01L 9/0052 of piezoresistive elements circuits therefor G01L9/06

Abstract

Provided is a pressure sensor including an elastic thin film including a first surface and a second surface that face each other, the elastic thin film including an elastomer material, a plurality of protruding deformable structures patterned on the first surface; a piezoresistive electrode formed along surfaces of the plurality of protruding deformable structures; and a counter electrode disposed to face the piezoresistive electrode.

Claims

1. A pressure sensor comprising:

an elastic thin film comprising a first surface and a second surface that face each other, the elastic thin film comprising an elastomer material, and the first surface being patterned to have a plurality of protruding deformable structures;

a piezoresistive electrode formed along surfaces of the plurality of protruding deformable structures, the piezoresistive electrode being shaped to protrude in accordance with a shape of the plurality of protruding deformable structures; and

a counter electrode disposed to face the piezoresistive electrode,

wherein the piezoresistive electrode protrudes toward the counter electrode, and

wherein as pressure applied to the counter electrode becomes stronger, a contact area between the piezoresistive electrode and the counter electrode becomes larger.

2. The pressure sensor of claim 1, wherein the elastic thin film comprises at least one of thermoplastic rubber, silicone rubber, fluoro silicone rubber, vinyl methyl silicone rubber, styrene-butadiene rubber, styrene-ethylene-butylene-strylene rubber, acryl rubber, butadiene rubber, chloro isobutylene isoprene rubber, polychloroprene rubber, epichlorohydrin rubber, ethylene propylene rubber, ethylene propylene diene rubber, polyether urethane rubber, polyisoprene rubber, isobutylene isoprene butyl rubber, acrylonitrile butadiene rubber, polyurethane rubber, and polydimethylsiloxane (PDMS).

3. The pressure sensor of claim 1, wherein the piezoresistive electrode comprises a mixture of a flexible or elastic polymer material and a conductive material.

4. The pressure sensor of claim 3, wherein the conductive material comprises at least one of conductive polymer, metal nanowire, metal nanoparticles, carbon nanotubes, and graphene.

5. The pressure sensor of claim 3, wherein the polymer material comprises at least one of polyester, polyvinyl alcohol, polyvinyl acetate, thermoplastic rubber, and silicone rubber.

6. The pressure sensor of claim 1, wherein cross-sectional areas of the plurality of protruding deformable structures are tapered as the plurality of protruding deformable structures extend towards the counter electrode.

7. The pressure sensor of claim 1, wherein the piezoresistive electrode is thinnest at uppermost portions of the plurality of protruding deformable structures, the uppermost portions being portions which are nearest to the counter electrode, and becomes thicker from the uppermost portions to bottom portions of the plurality of protruding deformable structures.

8. The pressure sensor of claim 1, wherein the piezoresistive electrode is conformably formed along shapes of the plurality of protruding deformable structures.

9. The pressure sensor of claim 1, wherein the plurality of protruding deformable structures comprise at least one of a cylindrical shape, a polygonal pillar shape, a cone shape, a polypyramid shape, a truncated cone shape, and a truncated polypyramid shape.

10. The pressure sensor of claim 1, wherein the counter electrode comprises a metal.

11. The pressure sensor of claim 1, wherein the counter electrode comprises an elastic conductive material.

12. The pressure sensor of claim 1, further comprising a plurality of other protruding deformable structures patterned on the second surface of the elastic thin film.

13. The pressure sensor of claim 12, further comprising:

another piezoresistive electrode formed on surfaces of the plurality of other protruding deformable structures; and

another counter electrode disposed to face the other piezoresistive electrode.

14. The pressure sensor of claim 1, wherein the piezoresistive electrode is continuously formed along the surfaces of the plurality of protruding deformable structures.

15. The pressure sensor of claim 1, wherein the piezoresistive electrode comprises a plurality of sub piezoresistive electrodes discontinuously formed along the surfaces of the plurality of protruding deformable structures, the sub piezoresistive electrodes being spaced apart from one another.

16. The pressure sensor of claim 15, wherein the counter electrode comprises a plurality of sub counter electrodes corresponding to the plurality of sub piezoresistive electrodes.

17. The pressure sensor of claim 15, wherein the counter electrode comprises a flat plate type electrode disposed to face the plurality of sub piezoresistive electrodes.

18. The pressure sensor of claim 1, wherein the counter electrode and the piezoresistive electrode are spaced apart from each other.

19. The pressure sensor of claim 18, wherein, when the pressure is applied to the counter electrode, the counter electrode contacts the piezoresistive electrode to thereby deform the piezoresistive electrode.

20. The pressure sensor of claim 1, wherein an equivalent resistance of the pressure sensor comprises:

a resistance of the counter electrode;

a resistance of the piezoresistive electrode; and

resistance at an interface between the counter electrode and the piezoresistive electrode,

wherein the resistance of the counter electrode is lower than the resistance of the piezoresistive electrode, and the resistance of the counter electrode is also lower than the resistance at the interface between the counter electrode and the piezoresistive electrode.