| 摘要 |
PURPOSE:To obtain an instrument with an excellent color discriminating capability and a high economical efficiency by changing a voltage applied to one liquid crystal cell, dividing a light signal with a specific wavelength transmitted through the liquid crystal cell into a plurality of kinds and processing each of the divided light signals by a series of signal processing circuit. CONSTITUTION:White light emitted from the light source 2 of a projection system is projected on an object 6 to be inspected. A liquid crystal cell 16 is inserted in a photosensitive circuit for receiving reflected light from the object 6. A plurality of different voltages are applied to the cell 16 by a liquid crystal driving circuit 17. The light transmitted through the cell 16 is received by a photodetector 11 and photoelectrically converted. The photodetector 11 has a high transmittance at a specific wavelength and can change the transmitted specific wavelength by the magnitude of the applied voltage to form a plurality of optical filters whose transmittances take peak values at the specific wavelengths depending on the transmittances corresponding to the applied voltages. The outputs of the photodetector 11 and the circuit 17 are A/D-converted 13, 13a and obtained data are stored in data memories 14, 14a, respectively. The calculation is conducted on the basis of those data in a processing unit 15 and a color is discriminated.
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