| 摘要 |
PURPOSE:To attain high accuracy in the white color balance adjustment by adjusting the intensity of the trichromatic light in the optimum state by means of the tri-color filter area setting and adjustment in terms of an electric circuit. CONSTITUTION:In terms of a lighting device 16, a rotating filter 14 obtained by arranging R, G and B light transmitting filters with different areas in a fan-shape on a light shielding frame is rotated at a constant speed, and hole detecting signals of R, G and B are outputted from a photo-interruptor 22, while an I/O amplitude ratio is inputted to a synchronous signal generator 28 set in accordance with R, G and B, thereby making the signal output into a pulse-like signal of related amplitude. A control voltage of a lamp drive current source 30 is formed out of this signal, and a lamp drive current I is changed in a staged shape, while the incident light quantity of a light source lamp 15 changes corresponding to the current I. When the area ratio of R, G and B filters 18-20, disposed beforehand on the rotating filter 14, is decided, and when the three signal output values of the synchronous signal generator 28 is set appropriately with respect to the hole detection, the spectral sensitivity characteristic of a solid-state image pickup element 3 can be compensated.
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