The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 02, 1979
Filed:
Mar. 22, 1977
Yoshiharu Ohta, Izumi, JP;
Hiroshi Hosomizu, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
In an electronic flash device, wherein electrical energy stored by a main capacitor and an electronic flash tube is fired by the stored energy, a relaxation oscillator is adapted to oscillate when the main capacitor is charged to a given voltage level, which is a condition for completion of preparation for flash tube operation. The relaxation oscillator includes a capacitor, a glow discharge tube, and a resistor and the oscillation thereof causes intermittent glow discharge through the glow discharge tube for indicating the completion of preparation for flash tube operation. The electronic flash tube is triggered to emit a light flash by the stored energy of the relaxation oscillator capacitor. Excitation of the flash device, even with a power supply switch open, is prevented by isolating the main capacitor from the trigger capacitor and also from the glow discharge tube to also prevent an indication of flash preparation. The trigger capacitor is also discharged through the resistor to prevent actuation of the flash device should the flash synchro switch be closed with the power supply switch open.