Opto-electronic scale reading apparatus
US5184014A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 1991 |
| Grant date | Feb 2, 1993 |
| Priority date | — |
| Expiry date | Oct 30, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An opto-electronic scale reading apparatus comprises a light source (20) which projects light via an index grating (22) onto a reflective scale (10). Light is reflected from the scale (10), passes through an auxiliary grating (36) and is incident upon an analyser grating (28), at which a plurality of periodic light patterns are formed. Light from the light source (20) travels initially parallel to the scale plane, and is subsequently deflected through 90.degree. by a beam splitter cube (26); the light is thus incident upon and reflected and off the scale (10) at 90.degree. to the scale plane. This arrangement enables large movements of the readhead in a direction perpendicular to the scale.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.