| 摘要 |
PURPOSE:To ensure to detect the luster area on the object to be read in, by providing the illumination optical system with a light source for use of illumination having the maximum light emission energy distribution, and providing the photodetection optical system with the photodetector having the maximum sensitivity. CONSTITUTION:The illumination light source 4 having the maximum light emission energy distribution at near-infrared ray area, as shown in the curve (a) of Figure, provides the reflection mirror 5 and illuminates on the mail 2 carried toward the arrow V with an angle of theta to the normal. The illumination light source 4 and the reflection mirror 4 constitute the illumination optical system 6. Further, the surface reflection light from the mail 2 is fed to the photodetector 8 via the image forming lens 7. The photodetector 8 is the self-scanning type CCD image sensor having the maximum sensitivity at near-infrared ray area as shown in the curve (b) of Figure. The image forming lens 7 and the photodetector 8 constitute the photodetection optical system 9. |
