| 摘要 |
<p>PURPOSE:To realize structure simplification and cost reduction and contrive to improve the signal/noise ratio by using a shielding member annularly arranged between the light receiving element and the light emitting element. CONSTITUTION:Light from the light emitting element 106 is reflected on the reflection plane 102a of the second cylinder 102 and on the outer peripheral surface 103b of the shielding member 103 and then put in irradiation to an object to be inspected which has bar codes via center of the first inner surface 101b of the first cylinder 101. When the irradiated part is a part of black bar code, the object to be inspected does not reflect that light, but reflects it in case of a white part, and the light is made incident to the light emitting element 105 via center of the second inner surface 101b of the first cylinder 101; thus, bar-code information can be read out. Since the first cylinder 101 is made of transparent synthetic resin, the refractive index of light of the light receiving element 106 becomes much smaller; accordingly, the noise made incident to the light receiving element 105 reduces, and the signal/noise ratio improves.</p> |
