Browse Prior Art Database

Sub-Master for Holographic Disk Copying

IP.com Disclosure Number: IPCOM000036824D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Beam, DL: AUTHOR [+2]

Abstract

This article describes a holographic disk manufacturing process in which an intermediate "sub-master" disk is first created from a master disk. The sub-master disk is then used for creating the copy holographic disks that are used in holographic bar code scanners.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 61% of the total text.

Page 1 of 1

Sub-Master for Holographic Disk Copying

This article describes a holographic disk manufacturing process in which an intermediate "sub-master" disk is first created from a master disk. The sub- master disk is then used for creating the copy holographic disks that are used in holographic bar code scanners.

In the production of the holographic scanning disks used in bar code scanners, copy disks were originally created from silver halide master disks by exposing a glass disk coated with a photo-sensitive film (dichromated gelatin) with laser light that had passed through the master disk under a prescribed set of conditions.

The silver halide master-making procedure is tedious and time consuming, requiring an extensive setup and disk assembly process. The damage of a master disk in the subsequent copying procedure is very costly. Furthermore, it is very difficult to produce subsequent master disks with the same characteristics as the original master disk.

In the sub-master approach, copy disks are first made of the original silver halide master disk. These copies are made on dichromated gelatin (DCG). The DCG copies can then be used to make the second generation copies that are actually used in the scanners. Once several DCG sub-masters are created, the original silver halide master disk can be put into safe storage until more sub- masters are needed.

The greater transmittance of the DCG sub-master disk provides an additional, and very significant, manufacturing bene...