Image projecting apparatus with margin detect means
US4903073A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1989 |
| Grant date | Feb 20, 1990 |
| Priority date | — |
| Expiry date | May 1, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K17/0019
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An image projecting apparatus using a microfilm strip carrying a series of image frames which have a margin area between adjacent two thereof, comprising a viewing screen for displaying an image reproduced from the microfilm strip, reels and motors for driving the microfilm strip to travel along a predetermined path, an optical system for irradiating the microfilm strip with a beam of light, the beam of light being transmitted as an information-carrying beam of light carrying image information detected from the microfilm strip, a projection lens for magnifying the information-carrying light beam and projecting the magnified beam of light onto the viewing screen, a photoelectric margin sensor responsive to at least a portion of the information-carrying light beam for producing an electric signal variable with the quantity of light incident on the photoelectric margin sensor, the photoelectric margin sensor being located off the location at which the information-carrying light beam is to be focussed by the projection lens, and a control circuit responsive to the electric signal from the photoelectric margin sensor for detecting the margin area intervening between any adjacent two of …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.