| 摘要 |
<p>An optical filter comprising a substrate (1) formed of a material transmissible for infrared rays, a band pass layer (2) formed on one side of the substrate and a short/long cutting layer (3) formed on the other side of said substrate, characterized in that the area of both said band pass layer (2) and said short/long cuttung layer (3) is slightly less than that of the substrate (1) so that exposed portions (4a,4b) are formed all over the circumferential portion of the substrate, and in that all the surface of the circumferential portions of the band pass layer and the short/long cutting layer is covered with a mask (5a,5b) formed of a material refelecting infrared rays. With this structure of the optical filter (7), leakage of light due to tipping of the edges of the band pass layer (2) or to mismatch of the band pass layer (2) and the short/long cutting layer (3) can be prevented. <IMAGE></p> |
