Browse Prior Art Database

Holographic Disk Clamping Device

IP.com Disclosure Number: IPCOM000035001D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Cowen, CH: AUTHOR

Abstract

Disclosed is a device that locates, clamps, and centers a holographic disk for the purpose of performing a functional test of its diffraction efficiency and other optical parameters. A holographic disk is used in bar code scanning products to deflect the laser beam in order to provide a scan pattern. The holographic disk to be tested is formed by adhering two glass substrates together with optical adhesive. The gel that contains the holographic information is sandwiched between the glass disks. The clamping device had to be designed such that the disk could be loaded automatically using a robot, the disk would be centered automatically, regardless of thickness and inner diameter tolerances, the glass would not be chipped or scratched, and the holograms would not be obscured by the device itself.

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Holographic Disk Clamping Device

Disclosed is a device that locates, clamps, and centers a holographic disk for the purpose of performing a functional test of its diffraction efficiency and other optical parameters. A holographic disk is used in bar code scanning products to deflect the laser beam in order to provide a scan pattern. The holographic disk to be tested is formed by adhering two glass substrates together with optical adhesive. The gel that contains the holographic information is sandwiched between the glass disks. The clamping device had to be designed such that the disk could be loaded automatically using a robot, the disk would be centered automatically, regardless of thickness and inner diameter tolerances, the glass would not be chipped or scratched, and the holograms would not be obscured by the device itself. The clamping action is pneumatically activated. When air pressure is introduced through a rotating union, a piston is forced upward and four clamping slides are pushed radially outward, thus centering and clamping on the inner diameter of the disk (see Figs. 1 and 2). The clamping surfaces are nylon to prevent chipping of the glass and are beveled to accommodate varying disk thicknesses and inner diameters and used to return the piston when air pressure is evacuated and an O-ring returns the four clamping slides as well as provides an additional non-slip gripping surface against the inner diameter of the disk. A beveled piston stop seating...