| 摘要 |
A symbol/character discrimination apparatus having a dark-field light source for applying light beams at a predetermined angle of incidence to the surface of a sample on which symbols and/or characters are formed in an indentation pattern, a CCD camera for detecting reflected light beams from the sample surface, and a condensing lens for illumination, diaphragm, and objective optical lens for detection, arranged between the CCD camera and the sample and having a common optical axis. The condensing lens is located between the light source and the sample to condense the light beams from the light source on the surface of the sample and guides the reflected light beams from the sample to the diaphragm. The diaphragm intercepts regularly reflected light beams among the reflected light beams and guides some of the irregularly reflected light beams to the objective optical lens for detection. The objective optical lens guides some of the irregularly reflected light beams to the CCD camera.
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