| 摘要 |
PROBLEM TO BE SOLVED: To improve the image quality of a subject, not only in a visible region but also in an infrared region, using a simple constitution. SOLUTION: The optical apparatus 100 is provided with an imaging lens 105 and an optical filter 104. The imaging lens 105 has a peak wavelength, at which the transmissivity of the light from the subject O becomes a maximum in the visible region and transmits light from the subject O. Furthermore, the optical filter 104 has a coating layer which lowers transmissivity not only in the visible region, but also in the infrared region at the same ratio at least on one surface between the front surface and the rear surface of a translucent resin substrate having transmissivity characteristics such that the transmissivity in the visible region is lower than that in the infrared region. By means of the optical apparatus 100 having such a constitution, composed transmissivity of the imaging lens 105 and the optical filter 104 becomes substantially constant, from a peak wavelength of the lens to the wavelength in the infrared region. COPYRIGHT: (C)2007,JPO&INPIT
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