Photographic illumination apparatus
US4634933A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1984 |
| Grant date | Jan 6, 1987 |
| Priority date | — |
| Expiry date | Dec 5, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides a photographic lighting apparatus for illuminating a photographic object in taking the object with a camera such as a television camera or an 8 mm movie camera. The photographic lighting apparatus is capable of illuminating the object practically at a fixed intensity of illumination regardless of the variation of the distance between the object and the lamp thereof by reducing the brightness of the lamp when the object is located near to the lamp and increasing the same when the object is located remotely. The brightness of the lamp is regulated by controlling the conduction angle of a thyristor connected to the lamp according to the output signal of a photometric circuit which measures the intensity of illumination of the object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.