| 摘要 |
<p>PURPOSE:To increase the reading sensitivity and to prevent the generation of an error for a bar code reader, by illuminating a bar code label through a semicylindrical lens and with use of plural light sources and compressing the reflected light down to about 1/3 and in the lengthwise direction of the bar to feed the compressed light to a photodetecting element. CONSTITUTION:Plural units of light source lamps 6 are arranged in the direction rectangular to a drawing and illuminate with reflection 17 a bar code 8a of a bar code label 8 through a semicylindrical lens 7. This reflected light is formed into an image to a condenser lens 12b of a reading sensor 12 via a flat reflector 9 and via a lens 10 and a slit 11. In this case, a scanning image is formed by compressing the lengthwise direction (rectangular to the paper surface) of the bar code down to about 1/3. Then the sensors 12 are arranged to perform a photoelectric conversion. The scanning image is detected by an electronic control circuit 13. In such a way, the entire surface of the label 8 is used effectively to increase the reading sensitivity as well as to avoid a reading error.</p> |
