Automatic white balance device

Abstract

Abstract PURPOSE:To reduce the possibility of an erroneous white balance correction by automatically adjusting the white balance by a standard color temperature signal when an illuminance is situated outside a prescribed range (proper illuminance) suitable for the adjustment of the white balance. CONSTITUTION:To the inversion input terminal of a comparator 21, a reference voltage VL corresponding to an excessively low illuminance is supplied and to the non-inversion input terminal of a comparator 22, a reference voltage VH corresponding to an excessively high illuminance is supplied. Accordingly, the comparator 21 outputs the signal of L level during the excessively low illuminance and the signal of H level at the time except the excessively low illuminance and the comparator 22 outputs the signal of L level during the excessively high illuminance and the signal of H level at the time except excessively high illuminance. The output signals of the comparators 21, 22 are supplied to an AND circuit 23 and the AND circuit 23 forms and outputs an illuminance discriminating signal of L level during the excessively high illuminance and during the excessively low illuminance and the illuminance discriminating signal of H level during a proper illuminance.

Inventors

• 👤 Kazuhiko Ueda
• 👤 和彦 上田

Bibliographic Details