Optical transducer
US4393591A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1981 |
| Grant date | Jul 19, 1983 |
| Priority date | — |
| Expiry date | Nov 13, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E10/50
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical transducer for determining the angular position of a rotating member relative to a fixed structure, comprises a notched disc 13 rotatable inside a support housing 12, a light emitter 18 and a plurality of photovoltaic cells 19 for detecting the passage of light through the disc notches. The active and passive elements of an electronic circuit connected to the photovoltaic cells are carried by a single ceramic plate 21, which also acts as a support for the cells 19. The circuit comprises trimming resistors in the form of films deposited on the ceramic plate and connected to the amplifiers by the photovoltaic cells. In order for the signals generated by the amplifiers to have constant, predetermined peak values, the values of the resistors are trimmed during the production stage by means of a laser which selectively burns away parts thereof. The ceramic plate 21 is cemented on to the transducer housing 12, which is then positioned on the laser apparatus. The operations involved in presetting the resistors is carried out with the transducer in operation, and the laser need only be focused and pre-positioned once for the entire circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.