| 摘要 |
PURPOSE:To accurately read data even when a flaw or dust exists on an optical card, by projecting beams of light on the same dot pattern on the optical card from plural light sources with different incident angles, and receiving the reflected light by a line sensor. CONSTITUTION:The beams of light from the light sources 3 and 5 are changed to parallel rays by passing through collimator lenses 2 and 4, and are made incident on the dot pattern of the optical card 1 at angles different with each other, and the reflected light are image-formed on the line sensor 10 via image- forming lenses 6 and 8 and mirrors 7 and 9. In such a way, even when the flaw or the dust, etc., exists on an optical path on one side, read error can be reduced by the beam of light advancing on the optical path on the other side, and the dot pattern can be read accurately. |
