| 摘要 |
PURPOSE:To take a precise color measurement regardless of variation in the quantity of light of the isochromatic light emitting element due to temperature fluctuations, a secular change, etc., by correcting the quantity variance of light of photodetecting elements for measurement with light emitting elements of red, green, and blue for reference light. CONSTITUTION:A microcomputer 11 sends timing pulses for (n)-time lighting to an LED driver 12, turning on the light emitting elements 1-3 of R, G, and B in time series. When an analog switch 13 is at ''L'', the signal of a photodetecting element 6 is supplied to an A/D converter 14. The values of the quantities of reflected light when the elements 1-3 are turned on and off are A/D-converted and sampled by the microcomputer 11 to calculate the addition mean value for (n) times, obtaining a reflection value from which a disturbing light component is excluded. Then, the switch 13 is switched to ''H'' to send lighting timing pulses to light emitting elements 7-9 of R, G, and B of an LED driver 15, turning on the light emitting elements. At the same time, the signal of a photodetecting element 10 is sent to the converter 14. Similarly, a reference value is calculated. The reflection value is corrected on the basis of a standard white plate, reflection values of R, G, and B for reference values, reflection value of sampling measurement, and respective reflection coefficients to perform the color measurement precisely. |
