Flash unit
US6345156B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 2000 |
| Grant date | Feb 5, 2002 |
| Priority date | — |
| Expiry date | Feb 25, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B2215/0503
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a flash circuit of a flash device, a Zener diode (37) is connected to a tap point (23f) located at an intermediate position of a secondary coil of an oscillation transformer (23). The oscillation transformer (23) and an oscillation transistor (22) constitutes an oscillation circuit. A potential at the tap point (23f) changes proportionally to a voltage charged in a main capacitor (41). When the main capacitor (41) is charged up to a set voltage, the Zener diode (37) conducts a Zener current, which activates a stopping transistor (38) and thus deactivates the oscillation circuit. When a flash charge switch (51) is turned on, an end of a light guide portion of a charge condition indicator (60) protrudes out of a lens-fitted film unit. When the main capacitor (41) is charged up to the set voltage, a light emission element starts lighting, and the light from the light emission element is projected from the end of the light guide portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.