PURPOSE: To eliminate harmful light generated from a hologram disk, and to improve the S/N by inserting an aperture between a perforated mirror and the hologram disk.
CONSTITUTION: An incident beam 11 to which a '0' point is a point light source passes through an opening 2a of a perforated mirror 2, and also, passes through a hole 13a of an aperture, and made incident on a hologram lens 3. The hologram lens 3 works as a transmission type diffracted grating, generates a scanning beam 5, and simultaneously, works as a reflecting diffracted grating, as well, and generates a harmful light 12. Subsequently, when a hologram disk 4 is rotated by a motor 10, a label on a scanning surface 6 is scanned by the scanning beam 5 by the same operation as usual, and a scattered light 8 is condensed onto a photodetector 9. On the other hand, the harmful light 12 is made incident on the aperture 13 since its polarized light is saved in a state of a circularly polarized light by including the rotating direction, as well, but screened by an area part than the opening part of the aperture, and not made incident on the photodetector 9.
| JPS5790783 | CARD COMPOSING CIRCUIT |
| JPH04165580 | MECHANICAL SCANNER |
HATANAKA YASUMUTSU
NISHI KAZUO
