| 摘要 |
PROBLEM TO BE SOLVED: To obtain an infrared image of good quality having a large S/N. SOLUTION: An infrared filter 5 is constituted to increase an attenuation amount of transmitting infrared ray at a center as compared with that at a peripheral edge. The filter 5 is disposed between a cold shield opening 3a and an infrared detector 4. An infrared ray amount passed via the opening 3a is constantly reduced at the peripheral edge of the detector 4. Since this reduced infrared ray amount is corrected by the filter 5, a uniform infrared ray amount is obtained by the detector 4 in a totally visual field region. Thus, an infrared image of good quality having no luminance difference can be obtained at the large S/N.
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