| 摘要 |
PROBLEM TO BE SOLVED: To obtain a card reader which can read information represented by a projection or recessed part by embossing, etc., out of a card which has large difference in the reflection factor of light between the projection or recessed part by embossing, etc., and a plane part or a card which is low in total reflection factor. SOLUTION: In this card reader, the light emitted by an LD (light source) 101 is passed through a cylindrical lens (lienar light generating means) 105 to irradiate the surface of a card 107 with linear light and the reflected light from the surface of the card 107 is guided to a PSD (photodetector) 115 which has its reflected light photodetection part divided at least along the linear light, thereby detecting the displacement distribution of the surface of the card 107 along the height. Here, this card reader is provided with a feedback means 122 which controls at least one of the light intensity of the PSD 115 and the amplification factor of the PSD 115 according to the level of the light signal obtained from the PSD 115 so that the level of the light signal obtained from the PSD 115 is higher than specified. |
