Digital exposure meter
US3990799A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1975 |
| Grant date | Nov 9, 1976 |
| Priority date | — |
| Expiry date | Jan 13, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/56
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an exposure meter having a row of lighting elements, such as lamps or light-emitting diodes, which correspond to respective exposure values, an improvement is made in that by utilizing a capacitor-charging integrating circuit, a constant current circuit and a ring-counter, an exposure value between two neighboring steps of the above-mentioned exposure values can be indicated by lighting said two lighting elements, and in that ranges of exposure indication can be switched by shifting a dial plate, which is facing the lighting elements, in interlocking relation with a range-shifting switch for switching its circuit for range selection, thus enabling a doubling of the steps of exposure values to be indicated with a limited number of lighting elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.