OPTICAL PYROMETRIC TRANSDUCER OBJECTIVE-LENS Russian patent published in 2015 - IPC G01J5/02 

FIELD: instrumentation.

SUBSTANCE: objective-lens comprises inlet leuco-sapphire window sealed in cylindrical metal case with the help of the frame metal sleeve with bead directed inward, toward leuco-sapphire window axis and telescopically coupled with said case. One of the frame sleeve ends has two opposed beads. Outer bead directed outward is located above said leuco-sapphire window. Inner bead abuts on outer surface of said leuco-sapphire window. Bead ID is smaller than window diameter.

EFFECT: increased aperture speed, stable light transmission.

2 cl, 3 dwg