Pressure sensing element and pressure sensor

Patent metadata

Field	Value
Publication number	US-10048141-B2
Application number	US-201414904782-A
Country	US
Kind code	B2
Filing date	Dec 24, 2014
Priority date	Dec 24, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

Provided is a pressure sensing element configured to be flexible, and capable of demonstrating a stable electrical reliability over a long period; and, a pressure sensor having such pressure sensing element. A pressure sensing element (100) has an electro-conductive pressure sensing film (14), a sensor electrode (12) provided at a position faced to the pressure sensing film (14), and an insulating layer (13) which creates a predetermined distance “A” between the pressure sensing film (14) and the sensor electrode (12) so as to keep them apart from each other, the pressure sensing film (14) being a resin film containing carbon particles (140); and, a pressure sensor (200) has the pressure sensing element (100), and a detection unit (210) which is electrically connected with the pressure sensing element (100) so as to detect contact resistance between the pressure sensing film (14) and the sensor electrode (12).

First claim

The invention claimed is:

1. A pressure sensing element comprising:
an electro-conductive pressure sensing film comprising a resin and carbon particles, the resin comprising polyimide or polyamide-imide as a main ingredient;
a sensor electrode provided at a position faced to the pressure sensing film; and
an insulating layer which creates a predetermined distance between the pressure sensing film and the sensor electrode so as to keep them apart from each other,
wherein a surface of the pressure sensing film, faced to the sensor electrode, has a surface roughness Rz of 0.10 μm or larger and 0.50 μm or smaller.

2. The pressure sensing element according to claim 1 , wherein the predetermined distance, measured in the initial state while keeping the pressure sensing film nearly flat, is 5 μm or longer and 25 μm or shorter.

3. The pressure sensing element according to claim 1 , wherein the pressure sensing film has a thickness of 6.5 μm or larger and 40 μm or smaller.

4. The pressure sensing element according to claim 1 , wherein the Young's modulus of the pressure sensing film is 5 GPa or smaller.

5. The pressure sensing element according to claim 1 , wherein the pressure sensing film has a surface resistivity of 7 kΩ/sq or larger and 30 kΩ/sq or smaller.

6. The pressure sensing element according to claim 1 , wherein the pressure sensing film has a heat resistance of 260 ° C. or higher.

7. The pressure sensing element according to claim 1 , wherein the Young's modulus of the pressure sensing film is smaller than the Young's modulus of a film of the same thickness composed of the resin which composes the pressure sensing film.

8. The pressure sensing element according to claim 1 , comprising a plurality of pressure sensor parts each configured by the pressure sensing film and the sensor electrode opposed to each other, and
a single sheet of pressure sensing film being opposed to the plurality of the sensor electrodes.

9. The pressure sensing element according to claim 8 ,
wherein the single sheet of pressure sensing film has, on the side thereof faced to the sensor electrodes, a slit which extends from the outer surface to a middle depth in the thickness-wise direction, and
the slit falls, in a plan view, between the plurality of sensor electrodes.

10. The pressure sensing element according to claim 1 , further comprising a flexible substrate,
the sensor electrode is formed at least on one surface of the substrate, and
the pressure sensing element being configured to be flexible.

11. The pressure sensing element according to claim 1 , further comprising an adhesion layer provided between a lower surface of the pressure sensing film and an upper surface of the insulating layer for bonding the pressure sensing film with the insulating layer,
the insulating layer has a first opening through which the pressure sensing film and the sensor electrode are opposed while placing a hollow space in between, and
the adhesion layer has a second opening larger than the first opening, the second opening entirely surrounding the first opening in a plan view.

12. A pressure sensor comprising:
the pressure sensing element described in claim 1 ; and
a detection unit which is electrically connected with the pressure sensing element so as to detect contact resistance between the pressure sensing film and the sensor electrode.

13. The pressure sensor according to claim 12 ,
wherein the pressure sensing element curves with a radius of curvature of 15 mm or smaller.

14. The pressure sensing element according to claim 1 , wherein when force is not applied to the pressure sensing element, the pressure sensing film does not directly contact the sensor electrode, wherein when force is applied to the pressure sensing element, the pressure sensing film directly contacts the sensor electrode.

Assignees

• Nippon Mektron Kk

Inventors

• Iwase Masayuki
• Toyama Keizo
• Ozaki Kazuyuki
• Ohdate Hirokazu
• Kimura Taisuke
• Toyoshima Ryoichi

Classifications

• A61B2562/0247

  Pressure sensors · CPC title

• A61B2562/125

  characterised by the manufacture of electrodes · CPC title

• G01L1/2287 Primary

  constructional details of the strain gauges (adjustable resistors H01C10/00) · CPC title

• A61B5/1117

  Fall detection · CPC title

• G01L1/2206

  Special supports with preselected places to mount the resistance strain gauges; Mounting of supports · CPC title