Browse Prior Art Database

Automatic Hologrpahic Disk Identification

IP.com Disclosure Number: IPCOM000039887D
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Cato, RT: AUTHOR [+3]

Abstract

This article describes a technique for automatically identifying the version of a holographic disk being used in an optical scanner. When optical scanners are used in industrial/manufacturing environments, different scanning applications require different holographic disks. One application may require a raster scan disk while another may require an omni-directional scan disk. Disk identification information can be incorporated into the disk, thereby making it possible to automate scanner setup to automatically identify the disk version. A holographic disk can consist of an annular array of holographic optical elements or facets which are separated by "markers" which define the facet edges. A "marker" may be a small reflection or transmission hologram or simply a clear gap.

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Automatic Hologrpahic Disk Identification

This article describes a technique for automatically identifying the version of a holographic disk being used in an optical scanner. When optical scanners are used in industrial/manufacturing environments, different scanning applications require different holographic disks. One application may require a raster scan disk while another may require an omni-directional scan disk. Disk identification information can be incorporated into the disk, thereby making it possible to automate scanner setup to automatically identify the disk version. A holographic disk can consist of an annular array of holographic optical elements or facets which are separated by "markers" which define the facet edges. A "marker" may be a small reflection or transmission hologram or simply a clear gap. In one type of disk design, one of the inter-facet gaps is designated a home position and is defined by an extra wide gap. There are at least two methods of including disk identification information on the disk itself. The first method is to code the home gap to provide a series of short pulses when the home gap traverses the laser beam. The decoded short pulses would identify the disk version. The simplest form of code would be to provide one short pulse for version 1, two short pulses for version 2, etc. Another method of automatically identifying the disk would be to include a second special inter-facet "marker" at a predetermined angular separation...