Devices and process for producing microfilm and microfiche recor

Details Devices and process for producing microfilm and microfiche recor Devices and process for producing microfilm and microfiche recor

1989-06-21

1992-10-20

James, Andrew J.

Optical: systems and elements

Holographic system or element

Using a hologram as an optical element

359 43, 359 44, G02F 113

Patent

active

051575280

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND

1. Field of the Invention
This invention relates to the production of microfilm and microfiche devices, and particularly to the production of microfilm and microfiche records which can be updated. For the sake of simplicity, microfiche devices will be referred to throughout the following description, but it will be apparent that the invention applies equally to the production of microfilm records and other imaging products.
2. Description of Related Art
Microfiches are optical storage media on which very large amounts of data can be stored on a small flexible sheet. For example, a standard A6 size microfiche can store the equivalent of ninety-eight A4 pages of data, arranged in an array of columns and rows. It is quite usual for many copies to be made from a master microfiche, for example where microfiches containing catalogues of books are distributed to libraries.
Such microfiches are usually produced by a photographic process, and because the whole of the photosensitive sheet is developed and fixed in the process, no further data can be subsequently added to the record. It will be apparent, therefore, that if the data requires updating, a new master must be produced and all of the copies must be discarded and new copies made.
A number of updatable microfiches are available. These rely on, for example, electro-photographic processes, or recording on thermoplastic materials, or a combination of dry silver films and thermal processes. Copies of such microfiches are at present made on silver-based photographic sheets or on diazo films, or vesicular copies are made. The copying process may retain the original image polarity or may invert it, depending upon which medium is used for the copies. For example, a positive contrast image will produce a negative copy on a silver-based photographic film. In each case, the copy cannot be altered once it is made, so new copies must be produced each time the master microfiche is updated. The copying process will, in many cases, involve the use of wet chemical processes.


SUMMARY OF THE INVENTION

It is an object of the present invention to provide an updatable optical storage device and a process for producing updatable and/or erasable microfiche masters, and for subsequently producing updatable and/or erasable copies therefrom.
It is a further object of the invention to provide a process for producing such a microfiche master in which all of the data items can be recorded on the microfiche simultaneously, i.e. the microfiche medium is parallel addressed.
According to one aspect of the invention there is provided an updatable optical storage device, comprising first and second electrically conductive layers between which a voltage can be applied; and a layer of a liquid crystal optical storage material and a photoconductive layer disposed between the electrically conductive layers.
According to another aspect of the invention there is provided a process for producing an updatable optical record on a storage device which comprises first and second electrically conductive layers with a layer of a liquid crystal optical storage material and a photoconductive layer disposed therebetween, the process comprising projecting on to the photoconductive layer an image to be stored; applying a voltage between the electrically conductive layers; heating at least those portions of the storage material where the storage image is to be stored; and allowing the storage material to cool while the image is applied.


BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawing, in which:
FIG. 1 shows a schematic cross section through a liquid crystal structure for forming a master or duplicate microfiche; and
FIG. 2 is a schematic cross section through photoconductive and liquid crystal layers of the structure for explaining the operation of the structure.


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic cross section through a liquid crystal structure which is

REFERENCES:
patent: 3723651 (1973-03-01), Gorog
patent: 3764211 (1973-10-01), Morse et al.
patent: 4440473 (1984-04-01), Sekimoto
patent: 4643533 (1987-02-01), Armitage
Kubota et al., "AN 8'.times.8' Display Using a Laser . . . " SID 83 Digest, May, 1983, pp. 44-45.
Nelson K. F. "Model for a Photo Conductor-Liquid Crystal Image Storage Panel", Photographic Science and Engineering, vol. 20, No. 6, Nov.-Dec. 1976, pp. 268-271.

Affiliated with

Also associated with

Rating

Devices and process for producing microfilm and microfiche recor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Devices and process for producing microfilm and microfiche recor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Devices and process for producing microfilm and microfiche recor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-197183