Pressure-sensitive sensor

• US 20040231969A1
• Filed: 05/19/2004
• Published: 11/25/2004
• Est. Priority Date: 05/21/2003
• Status: Active Grant

• Current Assignee: Nitta Corporation
• Original Assignee: Nitta Corporation
• Inventors: Ueda, Tsutomu, Kitano, Mitsumasa
• Granted Patent: US 7,112,755 B2
• Time in Patent Office: Days
• US Class Current: 200/511
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: H01H 2201/036 Variable resistance

Abstract

The pressure sensitive sensor includes a sheet base, an application-side and a receiving-side electrode provided on the sheet base and conducting coatings provided on the electrodes. The conductive electrodes have pressure-sensitive conductive ink containing conductive carbon black. Resistance between the application-side electrode and the receiving-side electrode changes by a contact area between the conductive coatings on the electrodes. The pressure-sensitive conductive ink has an enhanced strength as a resin and an enhanced effect of dispersion of the conductive carbon black by adding 30 to 70 parts by weight of silicon dioxide to 100 parts by weight of silicone elastomer component as a binder. The pressure-sensitive sensor has output stability and linearity at temperatures in a wide range from −40° C. to 85° C.

Claims

1. A pressure sensitive sensor comprising:

a sheet base;

an application-side and a receiving-side electrode provided on the sheet base;

conductive coatings provided on the electrodes, the coating being provided with pressure-sensitive conductive ink containing conductive carbon black;

in which resistance between the application-side electrode and the receiving-side electrode changes by a contact area between the conductive coatings on the electrodes; and

wherein the pressure-sensitive conductive ink has an enhanced strength as a resin and an enhanced effect of dispersion of the conductive carbon black by adding 30 to 70 parts by weight of silicon dioxide to 100 parts by weight of silicone elastomer component as a binder.

2. The pressure-sensitive sensor according to claim 1, wherein the silicon dioxide has a primary particle size of 7 to 40 nm, the conductive carbon black has a primary particle size of 20 to 40 nm and is contained at 3 to 50 parts by weight with respect to 100 parts by weight of the silicone elastomer component.

3. The pressure-sensitive sensor according to claim 1, further comprising a multi-point pressure-sensitive part with 0.3 or less of variation coefficient of output.

4. The pressure-sensitive sensor according to claim 2, further comprising a multi-point pressure-sensitive part with 0.3 or less of variation coefficient of output.

5. The pressure-sensitive sensor according to claim 1, wherein the sheet base is formed with a pair of sheet base members of polyethylene naphthalate, one of the members being provided with the conductive coating covering the application-side electrode and another of the members being provided with the conductive coating covering the receiving-side electrode, wherein a spacer is provided between the sheet base members so as to surround the conductive coatings and obtain a space between the conductive coatings opposing each other at a no-load state, and the spacer is formed with a UV coating agent layer and an adhesive agent layer.

6. The pressure-sensitive sensor according to claim 2, wherein the sheet base is formed with a pair of sheet base members of polyethylene naphthalate, one of the members being provided with the conductive coating covering the application-side electrode and another of the members being provided with the conductive coating covering the receiving-side electrode, wherein a spacer is provided between the sheet base members so as to surround the conductive coatings and obtain a space between the conductive coatings opposing each other at a no-load state, and the spacer is formed with a UV coating agent layer and an adhesive agent layer.

7. The pressure-sensitive sensor according to claim 1, wherein the sheet base is formed with a pair of sheet base members of polyethylene naphthalate, one of the members being provided with the conductive coating covering the application-side electrode and another of the members being provided with the conductive coating covering the receiving-side electrode, wherein a spacer is provided between the sheet base members so as to surround the conductive coatings and obtain a space between the conductive coatings opposing each other at a no-load state, and the spacer is formed a polyethylene naphthalate film and an adhesive agent layer.

8. The pressure-sensitive sensor according to claim 2, wherein the sheet base is formed with a pair of sheet base members of polyethylene naphthalate, one of the members being provided with the conductive coating covering the application-side electrode and another of the members being provided with the conductive coating covering the receiving-side electrode, wherein a spacer is provided between the sheet base members so as to surround the conductive coatings and obtain a space between the conductive coatings opposing each other at a no-load state, and the spacer is formed a polyethylene naphthalate film and an adhesive agent layer.

9. The pressure-sensitive sensor according to claim 1, wherein the sheet base comprises a pair of sheet base members of polyimede, one of the members being provided with the conductive coating covering the application-side electrode and another of the members being provided with the conductive coating covering the receiving-side electrode, wherein a spacer is provided between the sheet base members so as to surround the conductive coatings and obtain a space between the conductive coatings opposing each other at a no-load state, and the space is formed a polyimede film and an adhesive agent layer.

10. The pressure-sensitive sensor according to claim 2, wherein the sheet base comprises a pair of sheet base members of polyimede, one of the members being provided with the conductive coating covering the application-side electrode and another of the members being provided with the conductive coating covering the receiving-side electrode, wherein a spacer is provided between the sheet base members so as to surround the conductive coatings and obtain a space between the conductive coatings opposing each other at a no-load state, and the space is formed a polyimede film and an adhesive agent layer.