| 摘要 |
PROBLEM TO BE SOLVED: To provide a camera which keeps a focal distance of a lens constant even if a peripheral temperature varies. SOLUTION: The camera is equipped with: a light-emitting element 100 which emits light having a specific wavelength area, toward an object; an imaging element 107 which receives the light emitted from the light-emitting element 100; a BPF 105 which selectively transmits the light having the specific wavelength area; and lenses (a first lens group 101, a second lens group 102 and a third lens group 103) which make the light passing through the BPF 105, converge on the imaging element 107. The lenses include diffraction patterns which selectively act on the specific wavelength area. The diffraction patterns are composed so that they compensate variations in the light emission wavelength of the light-emitting element 100 due to temperature variations and variations in the focal distances of the lenses due to the expansion and contraction of the lenses. COPYRIGHT: (C)2011,JPO&INPIT
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