| 摘要 |
PROBLEM TO BE SOLVED: To provide a picture image having satisfactory brightness even in a distal observation part so as to reduce cost and prolong the service life of a lamp. SOLUTION: This controller is provided with an electronic shutter circuit 16 controlling light exposure quantity in a CCD 12 by an electronic shutter function, a microcomputer 18, a lamp voltage control circuit 23 controlling a lamp voltage of a lamp 21 variably, a DVP 27 forming a luminance signal, etc., to variably control a shutter speed by the electronic shutter circuit 16 based on the luminance signal obtained by the DVP 27. The device applies usually a fixed voltage V1 to the lamp 21 by the control of the microcomputer 18, and a lamp voltage is increased to the maximum V2 only when light quantity is short even in the lowest electronic shutter speed. According to this configuration, the lamp 21 is lit at a low voltage usually, and a high lamp voltage is used only in case of distal observation.
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