| 摘要 |
PURPOSE:To accurately set the limitations of a visual field at high yield by putting a pyroelectric element closely to one surface of an infrared condenser lens at an interval which is <=2 times as long as infrared-ray wavelength and installing a visual field limiting hood on the other surface so that it projects from the lens surface up to a constant distance. CONSTITUTION:The condenser lens 1 is made of germanium and has a convex surface of R=2.5mm as its infrared-ray incidence surface, its diameter is 3mm, and its thickness is 2.07mm; and the pyroelectric element 2 is adhered at the interval which is <=2 times as long as the infrared-ray wavelength, e.g. 3mum. Reflection preventive films 6 are vapor-deposited on both surfaces while its center wavelength is 10mum. Further, signal lead-out wires 3 and 4 are led out of electrodes on both surfaces of the element 2 respectively. Further, the visual field limiting hood 5 of the lens 1 serves as a base for mounting the lens 1, which is put entirely in the hood 5. Here, the hood 5 is 0.8mm high from the lens edge. Consequently, the limitations of the visual field can accurately be set at high yield. |
