Patent ID: 7538938

Claim:
An optical filter for flash lamps used in pulsed thermal imaging comprising: at least one optical filter member, said at least one optical filter member substantially covering a flash lamp; and said at least one optical filter member including a stack of multiple plates; said at least one optical filter member being formed of a selected filter material having predefined optical properties and forming said stack of multiple plates for allowing visible wavelengths to penetrate while substantially blocking infrared wavelengths, said blocked infrared wavelengths being in a predefined spectrum band range of an infrared camera, said blocked infrared wavelengths being blocked by said selected filter material forming said stack of multiple plates of said at least one optical filter member in both a flash period and a residual heat period for the flash lamp, said selected filter material forming said at least one optical filter member enabling substantially complete data obtained in a thermal imaging test to be usable and accurate, without errors introduced by flash reflection effect and residual heating effect.