| 摘要 |
PROBLEM TO BE SOLVED: To provide a lens unit 38 in which a plurality of lenses 40a and 40b are accommodated in a lens barrel 39, the lens unit being designed such that optical performance is retained by preventing, for example, expansion/contraction of air in the space A of the lens barrel 39 and condensation of dew on the lenses, and also a phenomenon such as flare is eliminated by preventing adverse effect of outside light. SOLUTION: A communication path 51 by which the space A and the outside B of the lens barrel communicate is formed in the spacer 391 of the lens barrel 39. The communication path 51 includes a circumferential groove 51b, vertical groove 51c, and straight through-hole 51a parallel to an axis O. Light entering the communication path 51 from the opening 39c of a small-diameter part 39b is prevented from entering the effective optical range L of the lens 40a. The arcuate projection 391a of the spacer 391 is used as a partition between the effective optical range L and non-aperture range M of the lens 40a. In addition, a material easy to absorb light is attached to the surface of the lens face a2 of the lens 40a, which is outside the effective optical range L, so that light does not enter the lens face (a) directly through the communication path 51. COPYRIGHT: (C)2007,JPO&INPIT
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