Capacitive type sensor
First Claim
Patent Images
1. A capacitive type sensor comprising:
- an insulating substrate;
first and second electrodes mounted on the insulating substrate to face each other; and
a gas sensitive film provided between the first and second electrodes and supported by the insulating substrate;
wherein the gas sensitive film has a linear thermal expansion coefficient of at least 2×
10−
5 per degree centigrade;
wherein the first and second electrodes have a linear thermal expansion coefficient which is substantially the same as the linear thermal expansion coefficient of the insulating substrate and which is not more than 1×
10−
5 per degree centigrade;
wherein said first and second electrodes each have a thickness from 1 μ
m to 11 μ
m, inclusive; and
wherein a face-to-face distance between said first and second electrodes is from 0.5 μ
m to 5 μ
m, inclusive.
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Abstract
A capacitive type sensor includes a pair of electrodes disposed on a surface of an insulating substrate to face with each other, and a water vapor sensitive disposed between and in contact with the electrodes. These electrodes are each constituted by an electrically conductive material whose linear thermal expansion coefficient is less than that of the water vapor sensitive film and is substantially the same as that of the insulating substrate, and suppresses a swelling of the water vapor sensitive film caused when the sensor is placed in a high temperature/humidity environment, thus suppressing drift deterioration of the sensor.
49 Citations
11 Claims
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1. A capacitive type sensor comprising:
-
an insulating substrate;
first and second electrodes mounted on the insulating substrate to face each other; and
a gas sensitive film provided between the first and second electrodes and supported by the insulating substrate;
wherein the gas sensitive film has a linear thermal expansion coefficient of at least 2×
10−
5 per degree centigrade;
wherein the first and second electrodes have a linear thermal expansion coefficient which is substantially the same as the linear thermal expansion coefficient of the insulating substrate and which is not more than 1×
10−
5 per degree centigrade;
wherein said first and second electrodes each have a thickness from 1 μ
m to 11 μ
m, inclusive; and
wherein a face-to-face distance between said first and second electrodes is from 0.5 μ
m to 5 μ
m, inclusive. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
Specification