Fade in and fade out arrangement for a motion picture camera
US4083630A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1975 |
| Grant date | Apr 11, 1978 |
| Priority date | — |
| Expiry date | Jul 24, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B19/26
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The disclosure relates to a fade circuit for a motion picture camera of the type which includes an automatic exposure control. The fade circuit includes a light emitting diode which illuminates the light sensitive device of the automatic exposure control to augment the ambient light levels normally received by the light sensitive device. The intensity of the light emitted by the light emitting diode is controlled by a variable current source which provides the light emitting diode with continuously increasing or decreasing current for increasing or decreasing the intensity of the light from the light emitting diode. Fade-in is obtained as the light intensity of the light emitting diode is gradually decreased from an initial intensity sufficient to close the diaphragm opening to zero intensity to allow the diaphram to assume an opened condition corresponding to ambient light levels. Fade-out is obtained as the light intensity of the light emitting diode is gradually increased from an initial zero intensity which causes the diaphragm to be in an open condition corresponding to ambient light levels to an intensity sufficient to close the diaphragm opening.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.