Patent ID: 9546948
Date: 2017-01-17
CPC Classifications: G01N

Claim:
1. A gas sensor that detects a gas that is a target of detection, comprising: a prism having a metal layer in an irradiation range of an incident light incident from a light source, and changing a path of the incident light at the metal layer to emit the incident light as an exit light; a gas absorbing liquid provided on a surface of the metal layer, and capable of absorbing the gas; and holding means covering the gas absorbing liquid, and causing the gas absorbing liquid to be held on the metal layer, wherein a dielectric constant of the gas absorbing liquid changes due to absorption of the gas in the gas absorbing liquid, and based on a change in light intensity of the exit light by a surface plasmon resonance phenomenon that occurs in the metal layer in response to the change in the dielectric constant, the gas is detected, and the holding means includes an internal space surrounded and formed by the surface of the metal layer, a wall portion, and a top plate portion having a plurality of through-holes bored therein, said wall portion being fixedly attached to the metal layer, so that the gas absorbing liquid is kept in the internal space while being exposed to an outside from the through-holes.