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 hybrid disc whose recordable-band grooves are wider and shallower than the pre-recorded ROM data pits. The ROM pits may be pre-recorded in ROM grooves that are at least as wide, but shallower than, the ROM pits. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters. The berms normally forming at the radial extremities of the pits and grooves in the masters, by thermal expulsion processes, may be reduced or eliminated by methods taught.

Abstract: A method and apparatus for manufacturing hybrid disc whose recordable-band grooves are wider and shallower than the pre-recorded ROM data pits. The ROM pits may be pre-recorded in ROM grooves that are at least as wide, but shallower than, the ROM pits. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters. The berms normally forming at the radial extremities of the pits and grooves in the masters, by thermal expulsion processes, may be reduced or eliminated by methods taught.

Abstract: A hybrid disc whose ROM grooves are less than 170 nanometers deep, and whose pre-recorded ROM data pits are more than 350 nanometers or less than 250 nanometers deep, as measured from the effective land level. The ROM pits may be pre-recorded in ROM grooves that are shallower than the ROM pits, where the ROM pits are narrower, of equivalent width or up to approximately 10% wider than the ROM grooves, respectively measured at half-depth, although the transverse extent of the ROM pits will not typically exceed that of the ROM grooves. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the R-band pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters.

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: A method and apparatus for manufacturing hybrid disc whose recordable-band grooves are wider and shallower than the pre-recorded ROM data pits. The ROM pits may be pre-recorded in ROM grooves that are at least as wide, but shallower than, the ROM pits. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters. The berms normally forming at the radial extremities of the pits and grooves in the masters, by thermal expulsion processes, may be reduced or eliminated by methods taught.

Abstract: A hybrid disc whose ROM grooves are less than 170 nanometers deep, and whose pre-recorded ROM data pits are more than 350 nanometers or less than 250 nanometers deep, as measured from the effective land level. The ROM pits may be pre-recorded in ROM grooves that are shallower than the ROM pits, where the ROM pits are narrower, of equivalent width or up to approximately 10% wider than the ROM grooves, respectively measured at half-depth, although the transverse extent of the ROM pits will not typically exceed that of the ROM grooves. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the R-band pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters.

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: 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: 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: A hybrid disc whose recordable-band grooves are wider and shallower than the pre-recorded ROM data pits. The ROM pits may be pre-recorded in ROM grooves that are at least as wide, but shallower than, the ROM pits. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. In the preferred embodiment, one beam of a dual beam apparatus records the ROM pits, while the other beam records the pre-grooves, and also records the ROM groove, if present. In most embodiments a thermal mastering process provides smooth feature surfaces to facilitate replication of the hybrid disc masters. The berms normally forming at the radial extremities of the pits and grooves in the masters, by thermal expulsion processes, may be reduced or eliminated by methods taught.

Abstract: Method and apparatus for measuring the spacing between adjacent information tracks on a recording medium. A spot of light is projected onto at least a portion of a first track and maintained in a constant spacing from a second track. A photodetector detects the amount of light reflected off of the disc from the spot in a predetermined direction, and provides an electrical signal as an output. The photodetector output provides a measurement of the track-to-track spacing of the recording medium.

Abstract: Method and apparatus for measuring the spacing between adjacent information tracks on a recording medium. A spot of light is projected onto at least a portion of a first track and maintained in a constant spacing from a second track. A photodetector detects the amount of light reflected off of the disc from the spot in a predetermined direction, and provides an electrical signal as an output. The photodetector output provides a measurement of the track-to-track spacing of the recording medium.

Abstract: Method and apparatus for measuring the spacing between adjacent information tracks on a recording medium. A spot of light is projected onto at least a portion of a first track and maintained in a constant spacing from a second track. A photodetector detects the amount of light reflected off of the disc from the spot in a predetermined direction, and provides an electrical signal as an output. The photodetector output provides a measurement of the track-to-track spacing of the recording medium.

Abstract: Method and apparatus for measuring the spacing between adjacent information tracks on a recording medium. A spot of light is projected onto at least a portion of a first track and maintained in a constant spacing from a second track. A photodetector detects the amount of light reflected off of the disc from the spot in a predetermined direction, and provides an electrical signal as an output. The photodetector output provides a measurement of the track-to-track spacing of the recording medium.

Abstract: A method and apparatus for detecting a property such as a defect in a surface to be scanned. A focusing, or objective lens is provided together with a subsystem for maintaining a substantially fixed distance between the focusing lens and the scanned surface. Scanning is effected by providing lateral movement between the lens and the surface. An off-axis light beam source is provided having a beam of light which is directed to pass through the lens to the scanned surface. A light beam sensing element is positioned so as to detect that portion of the light beam reflected off of the surface and transmitted back through the lens.

Abstract: Tracking apparatus and related method for use in a playback system for recovering information from a selected recording track on an optical record medium such as a video disc. The tracking apparatus produces a tracking error signal representative of the deviation of a scanning reading beam from the centerline of the selected track, and couples this error signal to a movable tracking mirror to form a servo for controllably positioning the beam in alignment with the track. The tracking apparatus further includes a defect detection circuit for monitoring the tracking error signal and producing a pair of control signals that indicate when video disc defects of prescribed types are being scanned, and a threshold detector circuit for comparing the error signal to prescribed positive and negative thresholds that are selectively-variable in accordance with the pair of control signals.