Optical path system for detecting vacuum degree of vacuum switch and method thereof

An optical path system for detecting a vacuum degree of a vacuum switch, comprising:

• a plasma excitation unit, which excites pulsed laser along an excitation optical path to bombard a shielding case of a vacuum switch to be detected, so as to generate a laser plasma;
• an optical path focusing unit, which focuses the excitation optical path and a collection optical path to focus the pulsed laser to the shielding case of the vacuum switch to be detected, and comprises a visible laser device for generating visible light and an adjustment device for adjusting the excitation optical path, wherein the visible light forms visible light spots on the shielding case of the vacuum switch to be detected along a visible optical path, the visible optical path at least partially overlaps the excitation optical path, and the collection optical path at least partially overlaps the visible optical path;
• an image collection unit, which collects a laser plasma image and a visible light spot focusing image, and comprises a gated detector for collecting the visible light spot image and the laser plasma image via the collection optical path;
• a vacuum degree detection unit, which is connected with the image collection unit to process the laser plasma image and extract characteristic parameters, and comprises a processor for obtaining, according to a relation between the characteristic parameters and a vacuum degree, the vacuum degree of the vacuum switch to be detected;
• and
• the excitation optical path comprises a laser reflector for receiving the pulsed laser, a first long-wave-pass dichroscope, a plano-concave lens, a plano-convex lens, a second long-wave-pass dichroscope, a reflector, and a focusing lens adjacent to the shielding case of the vacuum switch to be detected, which are connected in sequence.