| 摘要 |
PURPOSE: To detect a fingerprint in an IC card by comprising a sheet sensor mounted on an opposite face of a slab line which guides an input light in one direction while making the same reflected, and detecting the fingerprint on the plane coordinates on the basis of the reflected light from the fingerprint pressed to a fingerprint detecting area. CONSTITUTION: An input reference light 12 is totally reflected at a critical angleθo determined by the refraction factor n1 , n2 and is guided toward a right side in a drawing. On this occasion, a little light 13 is leaked. So that a part 13 of the reference light entered into a fingerprint detecting area 5, permeates a fingerprint 3a face of a thumb 3, and the reflected lights 14, 15 are scattered from, for example, one point P. The reflected lights 14, 15 are reflected by a boundary face of a core glass 9 and a clad glass 11 at the critical angleθo , and only the reflected light 14 of a conical part of a solid angleθrepresented by a solid line, reaches a CCD sensor 8. Whereby the distribution of the intensity of a reflection point is obtained on a CCD sensor 8 face just under the reflection point P, and the fingerprint pattern 16 can be obtained by performing the signal process such as the comparison of level, to the same.
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