| 摘要 |
PURPOSE:To obtain a highly reliable thermal body detector which deals easily with the size of a line and that of a thermal body by providing a thermal body detection head with a hood for adjusting the size of a spot. CONSTITUTION:At a terminal part of an optical fiber 7, a metallic cable 9 is provided and the metallic case 9, a lens 6 and its periphery define the detection head. The detection head is coupled with an optical receiver 8 and a heat-resistive tube 10 is provided covering the optical fiber 7. The detection head is provided with the hood for adjusting the size of the spot and the hood 11 is freely detachable or expansible and contractible. Consequently, the spot size is adjustable by the attachment and detachment, or expansion and contraction of the hood without moving the detection head itself. |
