Encoder measurement based on layer thickness
US6970255B1 · kind B1 · utility
8Cited by
17References
22Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2003 |
| Grant date | Nov 29, 2005 |
| Priority date | — |
| Expiry date | Apr 23, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/34707
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An encoder includes a layer on the scale that has a thickness that varies as a function of position along the length of the scale. The position of the sensor head with respect to the scale may be determined by measuring the thickness of the layer or index of refraction, e.g., using a reflectometer, and converting the thickness to the lateral position. In one embodiment, the thickness of the layer is used to provide a rough position of the sensor head with respect to the scale and an alignment target that includes periodic patterns on both the sensor head and scale is used to provide a refined position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.