JP-7855123-B2 - Strain gauge

Inventors

• 美齊津 英司
• 足立 重之
• 北原 昂祐
• 浅川 寿昭
• 北村 厚

Assignees

• ミネベアミツミ株式会社

Dates

Publication Date

20260507

Application Date

20250617

Claims (4)

1. A flexible resin base material, The substrate has a resistor formed from a material containing at least one of chromium and nickel, The resistor is A first functional layer formed directly on a predetermined surface of the substrate from a metal, alloy, or metal compound, and a first resistive portion mainly composed of α-Cr, formed directly on one surface of the first functional layer from a film containing Cr, CrN, and Cr₂N , A second functional layer formed directly on the predetermined surface of the substrate or on a surface parallel to the predetermined surface, from a metal, alloy, or metal compound; and a second resistive portion formed directly on one surface of the second functional layer, from a film containing Cr, CrN, and Cr₂N , with α-Cr as the main component, and formed with the grid direction different from that of the first resistive portion. The substrate comprises a third functional layer formed directly from a metal, alloy, or metal compound on the predetermined surface and an adjacent surface of the substrate, and a third resistive portion mainly composed of α-Cr, formed directly from a film containing Cr, CrN, and Cr₂N on one surface of the third functional layer. The first functional layer, the second functional layer, and the third functional layer have the function of promoting the crystal growth of α-Cr and forming a film mainly composed of α-Cr. The thickness of the first resistor, the second resistor, and the third resistor is 0.05 μm or more and 2 μm or less. A strain gauge in which the thickness of the first functional layer, the second functional layer, and the third functional layer is 1 nm or more and 100 nm or less.
2. The strain gauge according to claim 1, wherein the angle between the predetermined surface and the adjacent surface is an obtuse angle.
3. The strain gauge according to claim 1, wherein the first resistance section, the second resistance section, and the third resistance section are arranged so that their grid directions are perpendicular to each other.
4. A strain gauge according to any one of claims 1 to 3, comprising an insulating resin layer covering the resistor.

Description

This invention relates to strain gauges. A strain gauge is known that is attached to an object to be measured to detect its strain. The strain gauge includes a resistor for detecting strain, and the material used for the resistor is, for example, a material containing Cr (chromium) or Ni (nickel). Furthermore, the resistor is formed on one surface of a substrate made of, for example, an insulating resin (see, for example, Patent Document 1). Japanese Patent Publication No. 2016-74934 This is a perspective view illustrating a strain gauge according to the first embodiment.This is a cross-sectional view illustrating a strain gauge according to the first embodiment.This is a perspective view illustrating a strain gauge according to a modified example 1 of the first embodiment. The following describes embodiments for carrying out the invention with reference to the drawings. In each drawing, identical components are denoted by the same reference numerals, and redundant explanations may be omitted. <First Embodiment> Figure 1 is a perspective view illustrating a strain gauge according to the first embodiment. Figure 2 is a cross-sectional view illustrating a strain gauge according to the first embodiment, showing a cross-section taken along the line A-A in Figure 1 in a direction parallel to the YZ plane. Referring to Figures 1 and 2, the strain gauge 1 includes a base material 10, a resistor 30 (resistance parts 30x, 30y, and 30z), and a terminal part 41 (terminal parts 41x, 41y, and 41z). In this embodiment, for convenience, the side of the strain gauge 1 on which the resistance portion 30x is provided is referred to as the upper side or one side, and the side opposite to the side on which the resistance portion 30x is provided is referred to as the lower side or the other side. Furthermore, the surface on which the resistance portion 30x is provided in each part is referred to as one surface or the upper surface, and the surface opposite to the side on which the resistance portion 30x is provided is referred to as the other surface or the lower surface. However, the strain gauge 1 can be used upside down or positioned at any angle. Furthermore, "planar view" refers to viewing the object from the direction normal to the upper surface 10a of the base material 10, and "planar shape" refers to the shape of the object viewed from the direction normal to the upper surface 10a of the base material 10. The base material 10 is a member that serves as a base layer for forming the resistive portion 30x, etc., and is flexible. The thickness of the base material 10 is not particularly limited and can be appropriately selected depending on the purpose, but for example, it can be approximately 5 μm to 1000 μm. In particular, a thickness of 5 μm to 200 μm for the base material 10 is preferable in terms of strain transmission from the surface of the strain-generating body joined to the lower surface of the base material 10 via an adhesive layer, etc., and dimensional stability against the environment. A thickness of 10 μm or more is even preferable in terms of insulation. The base material 10 can be formed from an insulating resin film such as PI (polyimide) resin, epoxy resin, PEEK (polyetheretherketone) resin, PEN (polyethylene naphthalate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, or polyolefin resin. Note that "film" refers to a flexible material with a thickness of approximately 500 μm or less. Here, "formed from an insulating resin film" does not prevent the base material 10 from containing fillers or impurities in the insulating resin film. For example, the base material 10 may be formed from an insulating resin film containing fillers such as silica or alumina. The resistor 30 is formed on the substrate 10 and is a sensitive part that undergoes a change in resistance when subjected to strain. The resistor 30 includes resistance sections 30x, 30y, and 30z. That is, the resistor 30 is a collective term for the resistance sections 30x, 30y, and 30z, and is referred to as the resistor 30 when there is no need to distinguish between them. For convenience, in Figure 1, the resistance sections 30x, 30y, and 30z are shown with a textured surface. The resistive portion 30x is a thin film formed on the substrate 10 in a predetermined pattern, and is a sensitive portion that generates a change in resistance when subjected to strain. The resistive portion 30x may be formed directly on the upper surface 10a of the substrate 10, or it may be formed on the upper surface 10a of the substrate 10 via another layer. Figure 1 shows a three-dimensional Cartesian coordinate system where the grid direction of the resistive portion 30x is the X direction. Therefore, the resistive portion 30x can detect strain in the X direction. The resistive portion 30y is a thin film formed on the substrate 10 in a predetermined pattern, and is a sensitive portion that generates a change in resistance when strain is