Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information have been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data of a plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information has been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data relating to the plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information have been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data of a plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.

Abstract: An optical pickup apparatus has an optical system and an objective lens. The optical system has a semiconductor laser and an optical element. The semiconductor laser has an astigmatic difference in which an oscillated light beam has a light emission point in a semiconductor junction plane different from that in a plane normal to the semiconductor junction plane. The optical element is arranged in a light path of a light beam radiated from the semiconductor laser for over-correcting the astigmatic aberration of the light beam radiated from the semiconductor laser. The objective lens converges the light beam radiated by the light source via the optical element.

Abstract: A rotating intermediate drum having mounted thereon optical head is made smaller than stationary upper and lower drums in diameter and spiral grooves are formed on the rotating intermediate drum on its surfaces opposing the stationary upper and lower drums. An optical tape is transported in a floated condition relative to a drum circumferential surface owing to a synergy of a dynamic pressure based on the rotation of the rotating intermediate drum and the air exhausted from the spiral grooves. Therefore, an information signal is recorded on and/or reproduced from the optical tape when the optical tape is transported in the floated condition from the head drum having the trilayer structure composed of the stationary upper and lower drums and the rotating intermediate drum therebetween.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information have been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data of a plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information have been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data of a plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information have been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data of a plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.

Abstract: A recording and reproducing apparatus has a communicating unit, a reading unit, a storing unit, a control unit, and an output unit. The communicating unit transmits and receives data to/from an information center in which a plurality of additional information have been stored. The reading unit reads out recorded data from a recording medium on which a plurality of data and index data of a plurality of data have been recorded. The data read out from the recording medium by the reading unit is stored in the storing unit. The control unit reads out the additional information corresponding to the recording medium from which the data is read out by the reading unit from the information center by the communicating unit and writes the read-out additional information into the storing unit as additional data of the recording medium which is read out by the reading unit. The output unit outputs the data stored in the storing unit and the additional data.