Del Mar Avionics, Inc.

Robert C Beauchamp

David G Loeppky

Robert B Dobbin

Stephen K Shu

James R Norton

John A Rawson

Jim Norton

Daniel H Burkett

Method and apparatus for a portable clean environment used for recording optical disc masters by enclosing a light sensitive optical disc in a container that prevents ambient contamination from destroying the pristine environment necessary to create optical disc masters. A transparent optical disc, having an optically active lamina on at least one surface of the transparent optical disc, is enclosed in a dish shaped container that is generally free of particulate larger than 0.2 microns, the enclosure assembly effectively preserving a class 10 cleanroom environment. The dish shaped enclosure isolates the surface of the optical disc used to record data from contamination due to ambient conditions while exposing the nonwriting surface of the optical disc to enable laser writing. A foil seal protects the exposed nonwriting surface of the optical disc from ambient contamination during storage and until recording is desired. Once recording is desired, the foil seal is removed, the entire assembly is placed on the spindle of a turntable, and the transparent optical disc allows laser light to pass through the optical disc and focus on the optically active lamina to form pits within the optically active lamina by either ablating the lamina or by consuming the lamina. The optical disc is then removed from the cover in a cleanroom where electroforming is done on the optical disc to create a disc master.

Method and apparatus for creating optical disc masters

The invention discloses a method and an apparatus for creating optical disc recordings by forming pits having ideal shapes. These ideally shaped pits are improvements in the technology of disc mastering, due to the manufacturing and data playback advantages that are inherent in the ideally shaped pits. A disc substrate has a very thin partially reflective layer applied to the surface of the optical disc upon which data will be recorded. The substance used to make the partially reflective layer is normally considered opaque in more commonly occurring thicknesses. However, the partially reflective layer, is created to be so extremely thin that it becomes partially optically transparent. The partially reflective layer then has spin coated, thereon, an optically active lamina to enable the recording of data on the disc by laser means in the form of pits. The pits are created by having a laser light focusing on both the partially reflective layer and the optically active lamina, both which react to the irradiation causing a pit to be formed. The resulting pit is without a raised berm area surrounding the pit, in what is considered to be an ideal shape for a pit. An OD master can be created by finally depositing a conductive and reflective lamina over the pitted active lamina. The invention is also useful in providing increased laser tracking. Here, the partially reflective layer provides increased signal to noise ratio, enhancing laser tracking in both the recording and playback modes.

Optical recording medium and method for improved pit geometry and

A micro cassette recorder-player is disclsoed having capactity for increased signal-to-noise ratio by utilizing a mobile capstan which pulls tape out of a micro cassette and across an enlarged head placed distal to and shielded from all electric motors, solenoids, and inductors which typically create spurious electric and magentic flux fields that traditionally diminish S/N.

Expanded micro cassette player-recorder

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Westminster, CA, United States of America

Robert C Beauchamp