Planar surface scanning system
US4816920A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1986 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Nov 18, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/113
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A surface scanning system defining an optical path for scanning a planar surface, in which an angularly moving scanner deflects a portion of the path, an optical element aligned with stationary portions of the optical path is driven in rectilinear sinusoidal motion for providing focus correction as the surface is scanned, and in which the sinusoidal motion of the optical element and the motion of the scanner are caused to be interdependent in frequency and phase. The sinusoidal motion of the optical element maintains accurate focus on the planar surface. In another aspect a device for moving an optical element in linear resonant motion includes a cantilevered resilient support structure arranged to permit only linear motion of the element, and means for driving the element resonantly. In another aspect apparatus for detecting the position of a beam being scanned on a surface includes oscillator means whose frequency is synchronized to the changing velocity of the scanning on the surface, and means for switching the oscillator to its maximum resolution frequency during portions of the scanning when the beam is not within an active area of the surface. In another aspect, the reading …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.