Lens-fitted photo film unit and electronic flash device for use therewith
US5875357A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 1997 |
| Grant date | Feb 23, 1999 |
| Priority date | — |
| Expiry date | Nov 28, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B2219/045
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lens-fitted photo film unit has an electronic flash device (11, 30; 115) with a printed circuit board (173). The flash device includes a flash-emitting section (6, 170) for emitting flash light toward a photographic field, and a main capacitor (31, 155) for storing charge to be discharged in the flash-emitting section. The printed circuit board converts a current of a battery (12, 127) into a current of high voltage to be supplied to the main capacitor. The printed circuit board has a transistor (13, Tr1) for oscillation. A primary winding (15) has one end connected to the battery, and another end connected to a collector of the transistor. A secondary winding (16) is combined in mutual induction with the primary winding, has one end connected to the main capacitor, and another end connected to a base of the transistor. A tertiary winding (17) is combined in mutual induction with the secondary winding, has one end connected to the battery, and another end connected to the base of the transistor. An LED (21, 180) has a cathode connected to the one end of the tertiary winding with the battery, and an anode connected to the another end of the tertiary winding opposite to the battery…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.