Patent ID: 7987712

Claim:
A seal assembly for an optical sensor comprising: a) an elongated metal guide tube formed from a nickel based alloy and having a distal end portion defining an open distal end and an inner rear wall; b) a sapphire window disposed within the distal end portion of the metal guide tube, the sapphire window having a rear end surface abutting the inner rear wall of the distal end portion of the metal guide tube; c) a mounting sleeve formed from platinum or an alloy thereof for securing the sapphire window to the metal guide tube, the mounting sleeve having one portion joined to the metal guide tube and another portion joined to the sapphire window; and d) a hermetic glass seal located between an outer peripheral surface of the sapphire window and the rear end portion of the mounting sleeve, wherein the mounting sleeve provides a thermal expansion buffer between the metal guide tube and the sapphire window to keep the glass seal intact at operating temperatures.