Photoelectric angle measuring apparatus whose optically projecting focal line coincides with the axis of rotation of the scale carrier
US4987302A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1989 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Apr 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A photoelectric angle measuring apparatus for measuring relative angular positions of two objects which are rotatable relative to each other. The apparatus includes a scanning unit with a scanning scale connected to one of the objects. The scanning unit scans an angle scale of a scale carrier which is connected to the other object. Corresponding graduations of the scanning scale and the angle scale extend parallel to each other. The scanning unit includes an optically projecting element for the light ray path. The optically projecting element has a focal point which is located on the axis of rotation of the scale carrier or a focal line which coincides with the axis of rotation of the scale carrier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.