U.S. Philips Corporation

Marinus R De Bont

Petrus J Kivits

Jan Van Der Veen

Adriaan W De Poorter

Pieter Zalm

Cornelis Johannes Schoot

An information recording element which information is recordable by means of light, in particular laser light. The recording element comprises a substrate provided on one side with a radiation-cured layer, in particular a U.V. light-cured layer of a radiation-curable solvent-free liquid composition having at least one ethene group per molecule. Each radiation-cured layer is provided with a servo track on its surface remote from the substrate and an ablative information recording layer capable, by exposure to laser-type radiation, of forming an optically readable information track, situated on the surface of the radiation-cured layer in contact with the servo track.

Information recording element

An optical recording disc which comprises a disc-shaped substrate plate, for example, a plate manufactured from synthetic resin, for example, polymethylmethacrylate, which has on at least one side an ablative recording layer, for example, an amorphorous layer of a tellurium mixture, in which the substrate on the side of the recording layer has extrinsic instabilities, in particular surface discontinuities. For example, the surface of the substrate is roughened or provided with scratches. The substrate may also be provided with a separate coating layer comprising the discontinuities, for example, an inhomogeneous vapor-deposited layer, a coarse-granular layer of a dye, or a light-cured lacquer layer which has been roughened or provided with scratches.

Optical recording disc

The invention relates to an optical recording system and method in which information can be recorded and read by means of laser light on a recording medium. The recording medium comprises a circular substrate plate which is manufactured, for example, from a transparent synthetic resin and has a diameter from 5-50 cm and which is provided on at least one side with a recording layer consisting entirely or substantially entirely of a compound of phthalocyanine with a metal, metal oxide or metal halide. A very suitable recording layer is a layer of vapor-deposited vanodyl phthalocyanine in a maximum thickness of 200 nm. A metal layer of, for example, tellurium may be provided between the substrate and the recording layer or on the side of the recording layer remote from the substrate. The recording medium may also comprise an optically readable servo track. Upon recording information the element is exposed to pulsatory laser light, pits and/or holes being formed in the recording layer. Analog recording is possible. The element can be read both in transmission and in reflection.

Optical recording medium and method of optically recording information

The invention provides an information-recording element in which information can be written and read optically. The element is constructed from a transparent substrate, a laser light-absorbing, dye-containing auxiliary layer provided thereon, as well as a laser light-reflecting recording layer present on the auxiliary layer. Upon recording information the element is exposed to pulsated laser light via the substrate, holes being formed in the recording layer. The auxiliary layer stimulates the formation of holes, a saving of laser light energy being obtained. In a favorable embodiment the auxiliary layer has a laser light absorption of from 20 to 80% and a maximum thickness of 2500 A. In a further favorable embodiment the auxiliary layer also comprises an endothermal material, for example, nitrocellulose having a nitrogen content of at least 11%.

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Eindhoven, Netherlands

Marinus R De Bont