| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical low-pass filter in which influence of a reflected compressional wave is reduced. SOLUTION: At the end part of the advancing direction of the compressional wave of a light transmitting member 41 being one of the constituting elements of an optical low-pass filter, a multiple reflection part 45 is formed. A piezoelectric body is provided at a surface opposed to the multiple reflection part 45 of the light transmitting member 41. When a high-frequency voltage of 1 Mhz to 10 MHz is applied on the piezoelectric body, the compressional wave which advances in the inside of the member 41 is formed, and incident light is branched into the advancing direction by a periodical refraction factor distribution to be generated by the result. The compressional wave advancing upward in the figure is multiply reflected between the surfaces 451A, 451B to be attenuated. As a result, a wide part where the multiple reflection part 45 of the member 41 is not formed can be utilized as a filtering area. COPYRIGHT: (C)2006,JPO&NCIPI |
