Optical apparatus for the reproduction of images using a liquid crystal cell
US4334734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 1979 |
| Grant date | Jun 15, 1982 |
| Priority date | — |
| Expiry date | Oct 26, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/1252
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This invention relates to an optical apparatus for the reproduction of images, comprising an optical modulator formed by a nematic liquid crystal cell the length of which is at least equal to the width of the paper to be printed, comprising on an inner surface N electrodes corresponding to the N points forming a line and a counter electrode on the other surface, this cell being placed between two polarizers. The modulator produces or does not produce extinction of the radiation for each point, depending on whether a voltage is not or is applied between the counter electrode and the electrode corresponding to the point which is to be reproduced. The light-sensitive paper travels against the second polariser and is printed by a line of light modulated spatially along the N points. To ensure that the optical modulator thus produced functions satisfactorily, the light source should flash on when the liquid crystal has reached a stable state, i.e., just before the fluctuation in the control voltage applied between the counter electrode and the electrodes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.