Strain gauge including a barrier layer over a resistance body

Patent metadata

Field	Value
Publication number	US-12306053-B2
Application number	US-202218261351-A
Country	US
Kind code	B2
Filing date	Jan 13, 2022
Priority date	Jan 18, 2021
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

A strain gauge includes a flexible substrate; a resistor made from a film containing Cr, CrN, and Cr2N, on one surface of the substrate; and a resin barrier layer covering the resistor, and, in this strain gauge, in the barrier layer, a ratio of a moisture permeability (g/m2/24h) to a thickness (mm) is 5:1 or greater, and the thickness of the barrier layer is 100 μm or more and 3 mm or less.

First claim

The invention claimed is:

1. A strain gauge comprising:
a flexible substrate;
a resistor made from a film containing Cr, CrN, and Cr 2 N, on one surface of the substrate;
a barrier layer covering the resistor, the barrier layer being made of resin; and
an insulating stress relaxing layer between the resistor and the barrier layer,
wherein, in the barrier layer, a ratio of moisture permeability (g/m 2 /24h) to thickness (mm) is 5:1 or greater, and the thickness of the barrier layer is 100 μm or more and 3 mm or less,
wherein the insulating stress relaxing layer is an organic film having a lower Young's modulus than the barrier layer.

2. The strain gauge according to claim 1 , wherein the barrier layer is made from a fluoropolymer, an epoxy resin, or an acrylic resin.

3. The strain gauge according to claim 1 , wherein the barrier layer covers an upper surface and side surfaces of the resistor in a continuous manner.

4. The strain gauge according to claim 1 , wherein a gauge factor is 10 or more.

5. The strain gauge according to claim 1 , wherein the CrN and the Cr 2 N contained in the resistor are 20% by weight or less.

6. The strain gauge according to claim 5 , wherein a proportion of the Cr 2 N in the CrN and the Cr 2 N is 80% or more by weight and less than 90% by weight.

7. The strain gauge according to claim 1 , wherein the organic film includes resin or rubber.

8. The strain gauge according to claim 1 , wherein an entire material of the insulating stress relaxing layer is insulating.

9. A strain gauge comprising:
a flexible substrate;
a resistor made from a film containing Cr, CrN, and Cr 2 N, on one surface of the substrate;
a barrier layer covering the resistor, the barrier layer being made of resin; and
an insulating stress relaxing layer between the resistor and the barrier layer,
wherein, in the barrier layer, a ratio of moisture permeability (g/m 2 /24h) to thickness (mm) is 5:1 or greater, and the thickness of the barrier layer is 100 μm or more and 3 mm or less,
wherein an entire perimeter of the insulating stress relaxing layer is enclosed by the barrier layer.

10. A strain gauge comprising:
a flexible substrate;
a resistor made from a film containing Cr, CrN, and Cr 2 N, on one surface of the substrate;
a barrier layer covering the resistor, the barrier layer being made of resin; and
an electrode electrically connected to the resistor, the electrode having a first sidewall facing a second sidewall of the barrier layer,
wherein, in the barrier layer, a ratio of moisture permeability (g/m 2 /24h) to thickness (mm) is 5:1 or greater, and the thickness of the barrier layer is 100 μm or more and 3 mm or less,
wherein a portion of the flexible substrate is exposed to a gap between the first sidewall of the electrode and the second sidewall of the barrier layer.

Assignees

• Minebea Mitsumi Inc

Inventors

• Takimoto Tatsuya
• Takata Shintaro
• Toda Shinya
• Asakawa Toshiaki
• Adachi Shigeyuki

Classifications

• G01L1/2287 Primary

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

• G01B1/00

  Measuring instruments characterised by the selection of material therefor · CPC title

• G01B7/20 Primary

  formed by printed-circuit technique · CPC title