| 摘要 |
PURPOSE:To make a color decision with high accuracy by arranging a photodetector for obtaining respective stimulus values on one optical axis of a device for making the color decision by, specially, a three stimulus value method. CONSTITUTION:Two dichroic mirrors (DM) 1 and 2 which have different spectral reflection characteristics are arranged on the optical path of light to be measured at an interval while slanted to the optical path. Then the 1st photodetector 11 is arranged in the reflection direction of the light to be measured which is incident on the 1st DM 1, the 2nd photodetector 12 is arranged in the reflection direction of the 2nd DM 2, and the 3rd photodetector 13 is arranged on the optical path of transmitted light of the DM 2. An arithmetic device which discriminates and decides the color of the light to be measured by arithmetic operation based upon the outputs of those three photodetectors 11-13 are connected to the photodetectors. Thus, light in an optional specific wavelength range is reflected or transmitted by the light interference of a thin film to make the color decision with high accuracy.
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