Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.

Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.

Abstract: A method to produce improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. The method includes dual and/or dithered beam writing onto the structure and improved composition of the active layer of the structure.

Abstract: An apparatus to produce optical recording structures displaying improvements in the shape of three-dimensional features displayed therein. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. The apparatus may include dual and/or dithered beam writing elements.

Abstract: A method to produce improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. The method includes dual and/or dithered beam writing onto the structure and improved composition of the active layer of the structure.

Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.

Abstract: Disclosed are improvements in the transverse sectional shape of three-dimensional features displayed in optical recording structures—discs, cylinders, cards, multi-layered devices and structures replicated from them—to increase Figure of Merit. The cross-sectional shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. Disclosed methods include dual and/or dithered beam writing onto the structure and improved composition of the active layer of the structure. Also disclosed are apparatus for producing such improved features on optical recording structures, according to one or more of the disclosed methods.

Abstract: Method and apparatus for improving the characteristics of the surface effects on a replicated optical disc the master for which is recorded on an optical recording apparatus which includes a writing light beam source and an optical modulator for modulating the intensity of the writing beam of light above and below a threshold level of a relatively moving recording medium in response to a modulator drive signal for recording information on the medium, the light beam being capable of forming a track of surface effects or indicia in the relatively moving master recording medium when the writing beam is above threshold and incapable of forming surface effects in the relatively moving recording medium when the writing beam is below threshold. The method includes receiving a substantially rectangular waveform intended to control the optical modulator.

Abstract: Method and apparatus for improving the characteristics of the surface effects on a replicated optical disc the master for which is recorded on an optical recording apparatus which includes a writing light beam source and an optical modulator for modulating the intensity of the writing beam of light above and below a threshold level of a moving recording medium in response to a modulator drive signal for recording information on the medium, the light beam being capable of forming a track of surface effects or indicia in the moving master recording medium when the writing beam is above threshold and incapable of forming surface effects in the moving recording medium when the writing beam is below threshold. The method includes receiving a substantially rectangular waveform intended to control the optical modulator.

Abstract: Method and apparatus for improving the characteristics of the surface effects recorded on an optical disc, for use with an optical recording apparatus which includes a writing light beam source and an optical modulator for modulating the intensity of the writing beam of light above and below a threshold level of a moving recording medium in response to a modulator drive signal for recording information on the medium, the light beam being capable of forming a track of surface effects or indicia in the moving recording medium when the writing beam is above threshold and incapable of forming surface effects in the moving recording medium when the writing beam is below threshold.

Abstract: An optical storage media and information storage system and method for optically recording information in optically readable form. The DRAW recording medium of the present invention consists of a three layer structure: a transparent substrate; a uniform layer of a dielectric light-responsive material having a threshold energy level at which a physical change in the material occurs; and a highly electrically conductive and highly reflective overcoating on the opposite side of the light-responsive layer from the substrate. The recording method and system allow the concentration of the writing energy to a well defined volume within the thickness of the energy responsive layer or the uniform distribution of the energy throughout the layer by setting up a standing wave within the energy responsive layer by use of the electrically conductive reflecting layer.

Abstract: An optical storage media. The DRAW recording medium of the present invention consists of a three layer structure: a transparent substrate; a uniform layer of a dielectric light-responsive material having a threshold energy level at which a physical change in the material occurs; and a highly electrically conductive and highly reflective overcoating on the opposite side of the light-responsive layer from the substrate. The invention provides a DRAW recording medium which is capable of recording information immediately readable in accordance with the International Electrotechnical Commission optical disc standard for videodiscs.

Abstract: A signal processor and method for frequency compensating the drive signal for an optical modulator in an optical recording apparatus to make the exposure level modulation amplitude on the medium independent of the spatial frequency of the information being recorded. The processor compensates for exposure level modulation roll off at high spatial frequencies due to the finite size of the recording spot by increasing the amplitude of the modulator drive signal at high frequencies. The compensation is preferably the inverse of the modulation transfer function of the recording objective lens.

Abstract: An extended play videodisc and a method and apparatus for playing it. The disc carries every m th segment of a video program and the segments are repeated m times to approximate the original program. Prior art extended play discs have contained every other frame or every third frame of video, but the repeating of an entire frame results in poor motion reproduction and flickering scene transitions. The present invention preferably includes the repeating of a field of video an odd number of times. The fields are preferably arranged in order on the disc with n fields per revolution, the disc being rotated such that a new field is read every one and 1/n th revolution of the disc. The new segment is preferably read during the final repeating of the previous segment.

Abstract: A video recorder-playback machine is provided for recording and/or playing back video information from an information disc. The machine includes a "write" laser and a "read" laser respectively for generating record and playback optical beams which are focused upon the disc by an optical record-playback head. An optics carriage movably positions the head with respect to the disc in moving optical alignment with the "write" laser and carries the "read" laser in fixed optical alignment with the head. The machine includes apparatus for monitoring the record optical beam during operation in a record mode, and for substantially simultaneous operation in a playback mode to monitor the playback optical beam during the recording process.

Abstract: A method for recording video and audio information onto a recording medium which involves recording a carrier frequency signal, frequency modulated with composite color video information, and a subcarrier frequency signal, modulated with audio frequency information onto the recording medium and selecting the frequencies of the carrier and subcarrier signals such that the subcarrier frequency is lower than the second lower chroma sideband of the modulated carrier signal.

Abstract: A video recorder-playback machine is provided for recording and/or playing back video information from an information disc. The machine includes a "write" laser and a "read" laser respectively for generating record and playback optical beams which are focused upon the disc by an optical record-playback head. An optics carriage movably positions the head with respect to the disc in moving optical alignment with the "write" laser and carries the "read" laser in fixed optical alignment with the head. The machine includes apparatus for monitoring the record optical beam during operation in a record mode, and for substantially simultaneous operation in a playback mode to monitor the playback optical beam during the recording process.

Abstract: An optical recording medium for use with a recording apparatus of the type that focuses onto the medium, as the medium is moved in a prescribed fashion, a beam of light that is modulated in intensity in accordance with a data signal to be recorded. The recording medium includes a substrate having a smooth, planar upper surface, with a thin light-absorbing coating overlaying the surface, such coating including an explosive material such as nitrocellulose, and a light-absorbing dye. As the medium is moved with respect to the intensity-modulated beam, the explosive coating is selectively energized by the beam to induce spaced explosions threin, whereby corresponding optically readable irregularities, representative of the data signal, are formed in the outer surface of the coating.

Abstract: An improved process for making video discs, which enables the molding of replicas having substantially higher signal-to-noise ratios during playback. One aspect of the invention extends the duration of a photoresist development process to yield developed recording masters having spaced information-bearing pits with unexpectedly steeper sidewalls. Another aspect of the invention forms metallic stampers using an initial vapor deposition step carried out in an extremely low pressure of about 1.times.10.sup.-6 torr, to reduce oxidation and thereby improve conformity between the photoresist geometry and the stamper geometry.

Abstract: A lens assembly is positionally adjusted for precisely focusing a light beam upon a video information disc in a video recorder-playback machine. The lens assembly includes a focusing lens supported on an air bearing within an assembly housing for movement toward and away from the disc. A current conducting coil is movable with the focusing lens and is adapted to receive an electrical current indicative of instantaneous focusing error of the light beam upon the disc. A fixed magnetic field formed by a permanent magnet mounted on the housing between opposite pole pieces comprising portions of the housing is magnetically coupled with the coil whereby variations in the current result in adjustment of the position of the focusing lens with respect to the disc to correct the focusing error.