| 摘要 |
Provided is a filter unit which is suitable for imaging devices provided with high-resolution imaging elements. The filter unit (1) comprises: an annular filter frame (2); a discoid filter (3) accommodated in the space at the inner circumferential side of the annular filter frame (2); an annular elastic member (4) having an insertion part (41) inserted into a circumferential groove (32) formed in the circumferential surface (31) of the discoid filter (3); and a pressing ring (5) with which a pressing-force reception part (42) of the annular elastic member (4) is pressed against the annular filter frame (2) and fixed. In the filter unit (1), the discoid filter (3) is held without being in contact with the annular filter frame (2) and the pressing ring (5) which are hard, and thus the filter unit (1) is capable of substantially inhibiting warping of an entrance plane (3a) and an exit plane (3b) of the discoid filter (3), and is suitable for imaging devices provided with high-resolution imaging elements. |
