Patent ID: 9703092
Date: 2017-07-11
CPC Classifications: G01J,G02B,G02F,G03F

Claim:
1. An optical filter comprising: a first glass substrate; a second glass substrate that is disposed so as to oppose the first substrate; a first mirror that is disposed between the first glass substrate and the second glass substrate; a second mirror that is disposed between the first mirror and the second glass substrate; a first electrode that is disposed between the first glass substrate and the second glass substrate; and a second electrode that is disposed between the first electrode and the second glass substrate, the second glass substrate having a groove that surrounds the second mirror when viewed from a second glass substrate side to a first glass substrate side, the groove including a first side surface, a second side surface, a bottom surface, a first curved surface located between the first side surface and the bottom surface, and a second curved surface located between the second side surface and the bottom surface, the first curved surface being configured for easing a first stress concentration of the second glass substrate that is located between the first side surface and the bottom surface and that is generated during application of a voltage between the first electrode and the second electrode, the second curved surface being configured for easing a second stress concentration of the second glass substrate that is located between the second side surface and the bottom surface that is generated during application of the voltage between the first electrode and the second electrode, the first side surface continuing a first surface of the second glass substrate, the first surface opposing a second surface of the second glass substrate that is disposed at the first substrate side.