Focus-type encode device
US6194708A · kind A · utility
Inventors
Key dates
| Filing date | Jun 9, 1999 |
| Grant date | Feb 27, 2001 |
| Priority date | — |
| Expiry date | Jun 9, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An encode device, comprises a light source, an encode wheel and a light detector. A hollow dent is formed on the center part of the incident plane of the encode wheel. The inner circumference of the dent is provided with a ring-shaped lens such that the light impinging on the inner circumference of the dent is focused by the ring-shaped lens. The rim of the encode wheel is provided with a plurality of cylindrical lenses which are perpendicular to the ring-shaped lens such that the light leaving the encode wheel can be further focused. Therefore, the working beam projected toward the chip of the light detector has less interference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.