| 摘要 |
PURPOSE:To easily and surely decrease the flares and ghosts generated by the internal reflected light of the optical system to a level substantially negligible in practicable use without a limitation of a design by providing the specific reflection part of the effective diameter of the optical system on the effective coupling part of which detrimental rays are made incident by reflection with an antireflection means. CONSTITUTION:The luminous flux imaged on a CCD image pickup plane 3a is reflected by its surface and while the luminous flux diameter thereof is widened, the luminous flux travels backward in the optical system and is reflected again in the specific reflection part 2. At this time, the luminous flux is converted by the curvature of the subject side face 4a of a combined lens 4 and is made incident as flare light of high intensity again on the CCD image pickup surface 3a. An antireflection film is formed over the entire surface of the subject side face 4a of the combined lens 4 including the specific reflection part 2. Then, the intensity of the reflected light is decreased to <=1/10 and the flare light is suppressed down to the level negligible for practicable use. The light transmitted through the specific reflection part 2 is absorbed by a light shielding mask 1 arranged on the subject side of the combined lens 4, by which trouble is prevented. |
