| 摘要 |
PURPOSE:To obtain a small-sized reader by providing an optical means of transmitting a part of incident light and reflecting the remainder, in an image forming lens, and shortening optical path length. CONSTITUTION:At the internal center part of an image forming lens 31, a dichroic mirror 32 which transmits a part of incident light to the lens and reflects the remainder is provided. This mirror 32 reflects the 1st light having a long wavelength range including red light and transmits the 2nd light having a short wavelength range including blue light. For this purpose, the 1st light is photodetected by a photodetector 9 and the 2nd light is photodetected by a photodetector 10. Signals from those elements 9 and 10 are used for recording, thereby shortening the length of an optical path by use of a lens with short focal length. |
