| 摘要 |
PURPOSE:To accurately read the bar codes regardless of the distance between the bar code and a bar code reader as well as the soils and the blur by setting the different distances between each face of a rotary polyhedral mirror that reflects the laser beams to radiate the bar codes and a rotational axis. CONSTITUTION:A polyhedral mirror 301 consists of a prism having a regular hexagonal plan, etc., and the perpendicular plane mirrors 3021-3026 are attached to the side faces of the prism. These mirrors revolve around a rotational axis 303 which pierces through a regular hexagonal prism with eccentricity. Then the different distances are set between the center of the axis 303 and the mirrors 3021-3026 respectively. Therefore the reflecting surfaces move back and forth relatively to each other when the laser beams 2 are reflected by each face of the mirror 301. Then the reflecting points moves up and down. In this case, however, both the incident and reflecting angles have no change. Thus a bar code is scanned by the laser beams 21-23 which are parallel to each other. Then the bar codes are read accurately regardless of these bar codes and a bar code reading device as well as the soils and blur of the codes. |
