| 摘要 |
<p>PURPOSE:To enable to solve the problem on environmental hygiene like direct radiation to the eyes of workers, by avoiding the radiation of laser beam from the external enclosure. CONSTITUTION:The laser beam (a) passed through the focus lens 2 is reflected at the half mirror 3 and it is in high speed scanning with the oscillation of the mirror drive device 12 through the introduction of radial mirror 4. This beam (a) radiates the bar code plane 7 of carrier through the window of the scanner external enclosure 5. The beam (a) radiated is scatterd at the bar code plane 7, and a part of the scattered light passes through the same optical path as radiation and reflected on the mirror 4. This reflection light (a') is input to the code detection circuit 10 via the mirror 3, signal mirror 8, and light collection lens 9. When the switch 14 is switched from the contact (c) to (c'), the drive unit 12 is connected to the fixed power supply 15. When the voltage of the power supply 15 is taken as a voltage by which the mirror 4 is fixed at dotted lines, the external radiation of the beam (a) can be prevented.</p> |
