Optical focusing device and method
US6098887A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1998 |
| Grant date | Aug 8, 2000 |
| Priority date | — |
| Expiry date | Sep 11, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10811
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A hand held, omnidirectional symbology or bar code reader for imaging linear and two dimensional (matrix, maxi-code) bar codes over relatively long working distances. The reader includes an imaging system including a focusing objective taking lens and a two-dimensional photodetector that operate to form an image of a bar code in X and Y directions simultaneously and generate an electrical signal representative of the code for subsequent downstream processing which extracts information embedded in a bar code. Focusing is achieved via a rotating disk that carries a plurality of optical shims for different focus zones. A through-the-lens (TTL) targeting system is provided to visually assist the user in positioning the reader for a variety of code modalities to assure that a bar code will be captured within the field of view and be sharply imaged on the photodetector when the lens is focused. Two different forms of artificial illumination are provided to accommodate nearby codes that may be either specular or partially diffuse and more distant codes where the reflection characteristics have less impact on code contrast. Elements of the photodetector are used to assess available light l…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.