Browse Prior Art Database

Holographic Processes

IP.com Disclosure Number: IPCOM000074558D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 3 page(s) / 16K

Publishing Venue

IBM

Related People

Barrekette, ES: AUTHOR [+2]

Abstract

This description relates to holographic processes. In particular, it relates to their application in data processing apparatus.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 42% of the total text.

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Holographic Processes

This description relates to holographic processes. In particular, it relates to their application in data processing apparatus.

An important problem confronted in computer applications of holography is the "off-line" nature mostly characteristic thereof. Essentially, they are the "slow- write" type where the latter term generally signifies a process time of many seconds in a particular location. An exception to the above is "thermoplastic holography" which is a process that, in principle, at least, permits the writing, reading and erasing the holograms in a self-contained system. This "in situ" writing of erasable holograms is particularly important if holograms are to be useful for computer memories.

In accordance with one aspect of the process, there is provided an arrangement for making reversible, i.e., writable and erasable holograms using the techniques of electrophotographic copiers.

In accordance with this aspect, a hologram is generated in the conventional manner. Thus, in the case of a binary memory, a series of opaque and transparent dots is formed, in some cases, under computer control. The plane containing this information is then illuminated with a laser. The light passing through the information plane interferes with a subject "reference" beam in the plane of the electrophotographic storage medium. An electrostatic hologram is then directly stored.

The photoconductor which is employed may be transparent to the wave length of light used in reconstructing the image (real or virtual; the latter may be of use in display applications). An example of the photoconductor which may be used is, for example, a transparent organic photoconductor. The conducting medium is also transparent. With this aspect, easy reconstruction of the image in the transmission mode can be effected.

The electrostatic hologram can be toned either in the conventional manner or with a liquid toner. (It is realized, in this regard, that the toning with a liquid toner would permit resolution in the toning stage as high as 700 1/mm.) The hologram need not be fixed, and can be erased with a brush or like device. After the recharging of the photoconductor, a new hologram can be written.

In accordance with another aspect of this process, there is recognized the fact that electrostatic photography provides a mechanism for writing, storing, reading and tracing relatively high-resolution holograms/kinoforms. This can be considered from two approaches, as follows:

1) A large (printed) master is optically reduced onto an electrostatic photographic surface.

2) Computer-generated holograms/kinoforms are "printed" directly on the electrostatic photographic surface, either by the use of a matrix of wires or by some optical method such as with LED's (light-emitting diodes).

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In carrying out the above-mentioned process, the starting point can be holograms generated by a computer which may be assumed to be a binary amplitude hologram...