178results about "Carrier tracks/pits" patented technology

An optical information recording medium having a ROM area in which pre-pits are arranged in a line in advance, wherein a groove having a depth smaller than a depth of the pre-pits is formed between the pre-pits, and the groove has a width at junction parts smaller than a width of a part of the groove other than the junction parts. Preferably the following relationships are satisfied: ½ Wg<=Wpg<Wg; and Wpg<Wp, where Wp, Wpg and Wg represent a width of the pre-pit, the width of the groove at the junction parts, and the width of the other part of the groove other than the junction parts, respectively.

A recording medium, such as a high-density and / or read-only recording medium, such as BD-ROM, capable of preventing unauthorized duplication of data streams, written thereon, onto another medium, such as a BD-RE or BD-R, which includes physical mark information, and to methods and apparatuses for forming, recording, reproducing, and restricting playback of the recording medium to prevent unauthorized duplication.

Second digital information serving as copyright protection information can be stably and reliably read without any effect of a defect or pit missing on a disk-shaped recording medium. The second digital information is recorded onto a disk-shaped recording medium by wobbling a pit sequence recorded as a first signal. The second digital information is recorded so that a plurality of bits constituting the second digital information are allocated in a unit period of an identical sync signal contained in the first signal. During playback, the plurality of bits constituting the recorded second digital information are read a plurality of times every unit period of the sync signal, and information of the read bits is then integrated. Thus, information from a large number of wobbled pits across unit periods of a plurality of sync signals can be integrated to determine the bit values.

A recording medium and a recoding medium master, and a method of manufacturing the recording medium which comply with the standard of recording / reproducing characteristic established in the MD standard while enabling precise discrimination of the pit track and groove track and optical detection of the pits by optical pickup and the like are provided. Pits and grooves are arranged on a surface of a disc-shaped substrate so as to form a grooves and the ratio is from 1.00 exclusive to 1.13 inclusive. It is preferable that the track pitch of the grooves is from 1.50 mum inclusive to 1.70 mum exclusive. The width of the pits and grooves in the radial direction of the substrate is the same.

At least a portion of groove tracks in a information-data recording region of an optical recording medium comprises a plurality of groove portions separated by groove-absent portions in a rotational direction of the optical recording medium, each of the mark portions or each of the space portions includes one of the groove-absent portions. At least one of two groove tracks adjacent to prepit train, which is formed in land tracks, has a continuous groove portion or a groove-absent portion extending at least from a leading end to a trailing end of at least one prepit included in the prepit train in a rotational direction of the optical recording medium. The frequency band for separation of the groove tracks includes at least a portion of a frequency band of a modulated recording signal for recording information data on the optical recording medium.

A recordable optical recording medium comprising a recording layer containing an organic dye which can absorb a laser beam and a metal reflective layer directly or via another layer on a transparent supporting substrate having a pre-groove and a pre-pit, wherein the organic dye has a refractive index nk of 2.2 or more at a reproduction wavelength lambda2; in relation to the reproduction wavelength lambda2, the depths of the pre-groove and the pre-pit on the substrates are more than lambda2 / 4; and the following equations are satisfied:wherein r is a recording laser beam diameter represented by lambda1 / NA where lambda1 is a recording wavelength [mum] and NA is a numerical aperture for an object lens; wg [mum] and thetagr are a half value width and a cross-section tilting angle in a substrate radial direction for the pre-groove, respectively; and wp [mum], thetapr and thetapt are a half value width, a cross-section tilting angle in a substrate radial direction and a cross-section tilting angle in a tangential direction for the pre-pit, respectively.

Provided is a reproducing apparatus including: an optical system that obtains a signal light by radiating light emitted from a light source and generates a reference light from the light emitted from the light source, with respect to a recording medium, and that generates first to fourth groups of the signal light beams and the reference light beams, with respect to the superposed light in which the signal light and the reference light are superposed onto each other; a light receiving unit that receives light beams of the first to fourth groups of the signal light beams and the reference light beams respectively through first to fourth light receiving elements; and a reproduction signal generation circuit that calculates a first differential signal and a second differential signal, and that generates a reproduction signal by performing an arithmetic operation using the first and second differential signals.

According to the present invention, when a land-groove recording method is adopted, thermal crosstalk between a land and an adjoining groove is suppressed effectively. Inhomogeneity of a recording layer between the land and groove is suppressed effectively. A substrate for optical recording media comprises groove-like concave parts (2) and convex parts each created between adjoining concave parts. A border sidewall (4) between a concave part and an adjoining convex part (2) has a plurality of sidewall planes, that is, at least a first sidewall plane (41) that leads to the bed of the concave part and a second sidewall plane (42) that leads to the apical plane of the convex part. The first sidewall plane meets the bed of the concave part at an angle ranging from 120° to less than 180°. The second sidewall plane meets the bed of the concave part at an angle ranging from 90° to 110°. A discontinuous part (6) is produced at least along a borderline between the first sidewall plane and second sidewall plane. The presence of the discontinuous part (6) is effective in minimizing thermal crosstalk between the concave part (2) and convex part (3) and suppressing inhomogeneity of a recording layer between a land and an adjoining groove.