| 摘要 |
PURPOSE:To increase the quantities of light of weak light sources which differ in light emission wavelength alternately in inverse proportion to the light emission quantities of the respective light sources, and to take a precise color measurement regardless of the ruggedness and luster of an object, by arranging elements over a measurement surface successively along a parallel circle and photodetecting reflected light. CONSTITUTION:Light emitting elements 1-3 of R, G, and B are arranged successively over the measurement surface 6 along the circle in a parallel plane, and the same point on the measurement surface 6 is irradiated. Light which is projected at 45 deg. and photodetected at 0 deg. is condensed by a lens 4 and photodetected by a photodetecting element 5. The number of elements are decreased because of brightness 2-10 tims as great as those of light emitting elements 1-3, and the number of elements 3 of B is decreased; they are arranged symmetrically. A microcomputer 7 sends lighting timing pulses for (n) times to an LED driver 8 to turn on the light emitting elements 1-3 of R, G, and B in time series. A reflection value by disturbing light when the elements are turned off and data when they are turned on are A/D-converted and inputted to the microcomputer 7 to obtain an addition mean for (n) times. The microcomputer 7 performs calculations based upon the both to obtain signal light, finding values of R, G, and B. |
