Multiple focus optical system for data reading applications
US5565668A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Oct 15, 1996 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2207/1013
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An optical system and method for data reading having a light source which generates an optical beam directed toward an object to be read and a focusing system in the outgoing light path which establishes multiple beam functions. In a preferred application, a scanning system includes a multifocal lens having a single lens element having an inner lens portion of a first focal length and an outer annular lens portion with a second focal length, the optical system of a bar code scanner therefore establishing two separate focal positions from a single light source. Alternately, the system includes a focusing lens system with an corrector element disposed in the outgoing optical path, the corrector element having a plurality of optical zones, each zone having a different optical characteristic for modifying a portion of the outgoing optical beam. A zone may be a refractive region, a reflective region, a diffractive region, an empty region, a window region, or combinations thereof. In one embodiment, the system has two optical elements, namely a glass main focusing lens and a plastic corrector plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.