Strain gauge
According to the present disclosure, a strain gauge has: a flexible substrate; a resistor formed on the substrate; and a pair of electrodes formed on the substrate and electrically connected with the resistor via conductive traces, and, in this strain gauge, the conductive traces include a first metal layer and a second metal layer formed over an upper surface of the first metal layer, and the second metal layer is formed in a pattern that is different from a pattern of the first metal layer.
1 . A strain gauge comprising:
a flexible substrate;
a resistor formed on the substrate; and
a pair of electrodes formed on the substrate and electrically connected with the resistor via conductive traces,
wherein the conductive traces include a first metal layer and a second metal layer formed over an upper surface of the first metal layer,
wherein the second metal layer is formed in a pattern that is different from a pattern of the first metal layer, and
wherein, in plan view, part of the upper surface of the first metal layer is exposed from both ends of the second metal layer.
2 . The strain gauge according to claim 1 , wherein, in plan view, the second metal layer includes a part that extends obliquely with respect to a direction in which the first metal layer extends.
3 . The strain gauge according to claim 1 , wherein the second metal layer has a wavy pattern.
4 . The strain gauge according to claim 1 , wherein the second metal layer has a discrete pattern.
5 . The strain gauge according to claim 1 , wherein the first metal layer is formed integrally with the resistor by using a same material.
6 . The strain gauge according to claim 1 , wherein the second metal layer is made of a material that has greater elasticity than a material of the first metal layer.
7 . The strain gauge according to claim 1 , wherein the second metal layer is made of a material having a lower resistance than a material of the first metal layer.
8 . The strain gauge according to claim 1 , wherein a width of the first metal layer is 10 μm or more and 100 μm or less.
9 . The strain gauge according to claim 1 , wherein the conductive traces electrically connect each end of the resistor in a grid width direction with a corresponding one of the pair of electrodes.
10 . The strain gauge according to claim 1 , wherein the resistor is formed with a film containing Cr, CrN, and Cr 2 N.
11 . The strain gauge according to claim 10 , wherein a gauge factor is 10 or more.
12 . The strain gauge according to claim 10 , wherein the CrN and the Cr 2 N contained in the resistor are 20% or less by weight.
13 . The strain gauge according to claim 12 , 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.
14 . The strain gauge according to claim 1 , wherein the both ends of the second metal layer oppose each other in a direction perpendicular to a longitudinal direction of the second metal layer.
15 . The strain gauge according to claim 1 , wherein the part of the upper surface of the first metal layer exposed from the second metal layer extends along a longitudinal direction of the first metal layer.
16 . The strain gauge according to claim 1 , wherein a width of the second metal layer in a direction perpendicular to a longitudinal direction of the second metal layer is smaller than a width of the first metal layer in a direction perpendicular to a longitudinal direction of the first metal layer.