Patent ID: 6630798
Filing Date: 2003-10-07
Classification: H05B

Abstract:
An electronic flash device of an automatic light adjusting type, including a main capacitor for storing charge at a high voltage, a flash discharge tube for generating flash light with a current upon discharging said main capacitor, and a light adjusting circuit for adjusting a light amount of said flash light,wherein said light adjusting circuit includes: a reflected light measuring unit for outputting an integration voltage for representing a light amount of reflected light from a photographic field illuminated with said flash light; a non-contact switch for short-circuiting terminals of said main capacitor upon being turned on, to quench emission of said flash light in said flash discharge tube; a turn-on capacitor for being charged in response to said emission of said flash light, and for being discharged when said integration voltage comes up to a prescribed level, to turn on said non-contact switch upon a pulse of discharge; and a control switching element for keeping said reflected light measuring unit disabled while said turn-on capacitor is initially charged, and for enabling said reflected light measuring unit after voltage across said turn-on capacitor comes up to a predetermined level.