Divided blade and slit-forming blade for focal plane shutter
US5323205A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1993 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Sep 2, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B9/18
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the focal plane shutter having front and rear curtains disposed between lens and film on the camera, each of the front and rear curtains has a plurality of divided blades, and the shutter performs exposure to the film by forming a slit of a predetermined width between edge surfaces opposed to each other of the front and rear curtains, each of the divided blades comprises a light-reflective lens-side surface and a light-reflective slit-side edge surface having respective predetermined rates of diffused reflection. The lens-side surface is formed to have a rate of diffused reflection in a range of 7 to 30% within the region of visible light, as the predetermined rate of diffused reflection. The slit-side edge surface is formed to have a low rate of diffused reflection of not greater than 15% within the region of visible light, as the predetermined rate of diffused reflection. With this divided blades, the rate of reflection of the surface of the shutter curtain is applicable to a rate of reflection that enables TTL multi-pattern light adjustment and also unevenness of exposure is prevented from occurring.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.