Method and apparatus for reading a data record carrier
US4692913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1983 |
| Grant date | Sep 8, 1987 |
| Priority date | — |
| Expiry date | Nov 14, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The method of reading data from a data record carrier on which data has been recorded in arcuately nested, equal radii data rows which are equally spaced apart along a common centerline that is coextensive with a radius for each data row, comprises the steps of: incrementally moving the data record carrier in steps transversely of the data rows; projecting a light beam onto the plane in which the data record carrier moves; rotating the light beam about an axis parallel to the axis of said light beam to rotate said light beam in an arcuate path across the data record carrier, the radius of the arcuate path being the same or approximately the same radius of each data row; detecting scattered light outside the cone of specular reflection from the light beam impinging on the data record carrier, or the lack of scattered light, as the light beam traverses each data row; and sensing, and correcting for, difference between the arcuate path of said light beam and the arcuate path of the data row being traversed by said light beam to ensure that said light beam traverses approximately the same arc as that of each data row.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.