Sensor capable of sensing shear force

Patent metadata

Field	Value
Publication number	US-2016349124-A1
Application number	US-201514788292-A
Country	US
Kind code	A1
Filing date	Jun 30, 2015
Priority date	May 26, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A sensor able to detect shearing forces as well as simple pressure includes a substrate, a support secured to the substrate, and shear force sensing unit located at an exterior surface of the support facing away from the substrate. The support can be elastically deformed in proportion to the shearing force or pressure. The shear force sensing unit includes first piezoelectric films on outer opposing shoulders of each support, the first piezoelectric film being elastically deformed with the support and outputting a signal accordingly. The magnitude of simple pressure is recorded by similar deformation of a second piezoelectric film entirely covering its support.

First claim

What is claimed is:

1 . A sensor capable of sensing a shear force comprising:
a substrate; at least one support secured to the substrate, each of the at least one support configured to be elastically deformed and three-dimensionally arched away from the substrate; and at least one shear force sensing unit located at an exterior surface of each of the at least one support facing away from the substrate, each of the at least one shear force sensing unit including a first piezoelectric film sandwiched between two first electrodes, wherein the first piezoelectric film is configured to partially cover the support so that each of the at least one shear force sensing unit is three-dimensionally arched, whereby when one of the at least one support is elastically deformed, the first piezoelectric film is configured to output a signal corresponding to a degree of deformation thereof via one of the first electrodes.

2 . The sensor of claim 1 , wherein each of the at least one support comprises two opposite flange portions and an arched portion located between the two flange portions; each of the at least one support is secured to the substrate via the two flange portions; the arched portion is three-dimensionally arched away from the substrate; the first piezoelectric film partially covers the support, with an upper end being secured to a top point of the arched portion and a lower end being secured to a flange portion of the support.

3 . The sensor of claim 2 , wherein each of the at least one support comprises two shear force sensing units; two top points of the arched portion with a distance between them anchor the upper ends of the first piezoelectric films and two opposing flange portions of the support anchor the lower ends of the first piezoelectric films.

4 . The sensor of claim 3 , comprising two supports, wherein the flange portions of the two supports are perpendicular to each other, causing the first piezoelectric films of the shear force sensing units covering the two supports to be able to be elastically deformed along four different directions parallel to the substrate.

5 . The sensor of claim 2 , wherein the output signal from the shear force sensing unit is an electrical vibration corresponding to a vibration produced by a vibration in the first piezoelectric film; the substrate further comprises a vibrator and a processor located on the substrate; the vibrator is electrically connected to one end of the first electrode of each of the at least one shear force sensing unit; the processor is electrically connected to the opposite end of the first electrode of each of the at least one shear force sensing unit; the vibrator is configured to output a reference electrical vibration with a reference frequency to each of the at least one shear force sensing unit; the processor is configured to obtain an actual electrical vibration from each of the at least one shear force sensing unit, and calculate a value of a shear force being applied according to a difference between an actual frequency of the obtained actual electrical vibration and the reference frequency.

6 . The sensor of claim 2 , wherein the output signal from the shear force sensing unit is a voltage signal; the substrate comprises a signal amplifier and a processor located on the substrate; the signal amplifier is electrically connected to the first electrode of each of the at least one shear force sensing unit, and is configured to obtain the voltage signal from each of the at least one shear force sensing unit and amplifies the obtained voltage signal; the processor is configured to filter the amplified voltage signal, and calculate a value of the shear force being applied according to the voltage signal after filtered.

7 . The sensor of claim 2 , wherein the first piezoelectric film is made of organic piezoelectric material or inorganic piezoelectric material.

8 . The sensor of claim 7 , wherein the organic piezoelectric material is selected from a group consisting of polytetrafluoroethylene, polyvinylidene fluoride, polytetrafluoro ethylene, polychlorotrifluoro ethene, polypropylene, polyethylene, and polyethylene terephthalate.

9 . The sensor of claim 7 , wherein the inorganic material is lead zirconate titanate.

10 . The sensor of claim 2 , wherein the two first electrodes are made of a material selected from a group consisting of gold, silver, platinum, aluminum, nickel, copper, titanium, and selenium.

11 . The sensor of claim 2 , further comprising at least one pressure sensing unit, wherein the at least one pressure sensing unit is secured to the exterior surface of each of the at least one support; each of the at least one pressure sensing unit comprises a second piezoelectric film sandwiched between two second electrodes; the second piezoelectric film is configured to partially cover the support, with each end being secured to an opposing flange portion of a support, so that each of the at least one pressure sensing unit is three-dimensionally arched; whereby when one of the at least one support is elastically deformed, the second piezoelectric film is configured to output a signal corresponding to a degree of deformation thereof via one of the second electrodes.

12 . The sensor of claim 11 , wherein the output signal from the pressure sensing unit is an electrical vibration corresponding to a vibration produced by a vibration in the second piezoelectric film; the substrate further comprises a vibrator and a processor located on the substrate; the vibrator is electrically connected to one end of the second electrode of each of the at least one pressure sensing unit; the processor is electrically connected to the opposite end of the second electrode of each of the at least one pressure sensing unit; the vibrator is configured to output a reference electrical vibration with a reference frequency to each of the at least one pressure sensing unit; the processor is configured to obtain an actual electrical vibration from each of the at least one pressure sensing unit, and calculate a value of a pressure being applied according to a difference between an actual electrical frequency of the obtained actual electrical and the reference frequency.

13 . The sensor of claim 11 , wherein the output signal from the pressure sensing unit is a voltage signal; the substrate comprises a signal amplifier and a processor located on the substrate; the signal amplifier is electrically connected to the second electrode of each of the at least one pressure sensing unit, and is configured to obtain the voltage signal from each of the at least one pressure sensing unit and amplifies the obtained voltage signal; the processor is configured to filter the amplified voltage signal, and calculate a value of the pressure being applied according to the voltage signal after filtered.

14 . The sensor of claim 11 , wherein the two second piezoelectric film are made of organic piezoelectric material or inorganic piezoelectric material.

15 . The sensor of claim 14 , wherein the organic piezoelectric material is selected from a group consisting of polytetrafluoroethylene, polyvinylidene fluoride, polytetrafluoro ethylene, polychlorotrifluoro ethene, polypropylene, polyethylene, and polyethylene terephthalate.

16 . The sensor of claim 14 , wherein the inorganic material is lead zirconate titanate.

17 . The sensor of claim 11 , wherein the second electrodes is made of a material selected from a group consisting of gold, silver, platinum, aluminum, nickel, copper, titanium, and selenium.

18 . The sensor of claim

Assignees

• Hon Hai Prec Ind Co Ltd

Inventors

• Chang Jen-Tsorng

Classifications

• G01L1/16 Primary

  using properties of piezoelectric devices · CPC title

• G06F1/1626

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• G06F2203/04105

  Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position · CPC title

• G06F1/1694

  the I/O peripheral being a single or a set of motion sensors for pointer control or gesture input obtained by sensing movements of the portable computer · CPC title

• G06F3/041

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