Optical information recording medium having first and second tracks and apparatus for recording to and reproducing from the medium

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area, the address area of the first track having a control information for the information recording area in a direction of the tracks,
• the address area comprises address pits formed exclusively in a part of the first tracks, the address pits being formed in a pattern,
• a track pitch of the first tracks is smaller than 1.2 .mu.m, and
• a width of the first tracks is smaller than a width of the second tracks.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks,
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern,
• a track pitch of the first tracks is smaller than 1.2 .mu.m,
• a width of the first tracks is smaller than a width of the second tracks, and
• the address area includes at least two zones located in the direction of the tracks, and the first tracks comprise the address pits in at least one of the zones.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks,
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern,
• a track pitch of the first tracks is smaller than 1.2 .mu.m,
• a width of the first tracks is smaller than a width of the second tracks, and
• the first and second tracks further have an address start zone provided prior to the address area indicating a start of the address area, and in the address start zone, patterns of the tracks adjoining to each other are identical.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks,
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern,
• the address area includes at least two zones located in the direction of the tracks, and
• in the address area, a pattern of the address pits of the first track in at least one of the zones is identical to a pattern of the next first track.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam, both of the first and second tracks being used for recording information;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area, the address area of the first track having a control information for the information recording area in a direction of the tracks,
• a width of the first tracks is identical to a width of the second tracks, and
• the address area comprises address pits formed exclusively in a part of the first tracks, the address pits being formed in a pattern.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam, both of the first and second tracks being used for recording information;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks;
• a width of the first tracks is identical to a width of the second tracks,
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern, and
• the address area includes at least two zones located in the direction of the tracks, the first tracks comprise the address pits in at least one of the zones, and the first tracks in the zone adjoining the zone with the address pits have a continuous shape.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam, both of the first and second tracks being used for recording information;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks,
• a width of the first tracks is identical to a width of the second tracks,
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern, and
• the address area includes at least two zones located in the direction of the tracks, and in the address area, a pattern of the address pits of the first track in at least one of the zones is identical to a pattern of the next first track.

An optical information recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam, both of the first and second tracks being used for recording information;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks,
• a width of the first tracks is identical to a width of the second tracks,
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern, and
• the first and second tracks further have an address start zone provided prior to the address area indicating a start of the address area, and in the address start zone, patterns of the tracks adjoining to each other are identical.

An optical information recording/reproducing apparatus for reproducing an information signal be irradiating a laser light beam onto a recording medium, the recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks, and
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern;
• the apparatus comprising:
• light detecting means for detecting a reflected light from the recording medium;
• tracking means for focusing the incident light beam onto the second track based on an output from the light detecting means;
• and
• address demodulating means for demodulating an address signal from the address pits formed in the address area by comparing the output from the light detecting means with a reference level.

An optical information recording/reproducing apparatus for reproducing an information signal by irradiating a laser light beam onto a recording medium, the recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks, and
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern,
• the apparatus comprising:
• light detecting means for detecting a reflected light from the recording medium, the detecting means divided in a direction perpendicular to the direction of the tracks;
• tracking means for focusing the incident light beam onto the second track based on an output from the light detecting means;
• summing means for obtaining a summation signal of the outputs from the light detecting means;
• differential means for obtaining a differential signal of the outputs from the light detecting means;
• absolute value means for obtaining an absolute value signal of an output from the differential means;
• address demodulating means for demodulating an address signal by comparing an output from the absolute value means with a first reference level;
• and
• information demodulating means for demodulating an information recorded on the recording layer by comparing a differential signal between an output from the summing means and the output from the absolute value means with a second reference level.

An optical information recording/reproducing apparatus for reproducing an information signal by irradiating a laser light beam onto a recording medium, the recording medium comprising:

• a substrate including first tracks having a first face and second tracks having a second face, the first face and the second face being optically at different positions in a direction of an incident light beam, both of the first and second tracks being used for recording information;
• and
• a recording layer provided on the substrate on which at least one optically detectable change is caused by irradiating the light beam;
• wherein the first and second tracks have an information recording area and an address area having a control information for the information recording area in a direction of the tracks,
• a width of the first tracks is identical to a width of the second tracks, and
• the address area comprises address pits in a part of the first tracks, the address pits being formed in a pattern,
• the apparatus comprising:
• an optical system for irradiating the light beam on the recording medium;
• tracking error detecting means for detecting an offset between a target track and the light beam based on a reflected light or a transmitted light from the recording medium;
• tracking controlling means for moving the incident light beam to scan the track based on an output from the tracking error detecting means;
• inverting means for inverting a polarity of the tracking controlling means dependent on whether the first tracks or the second tracks are scanned;
• signal level comparing means having a reference level, the reference level changing into at least two levels in accordance with the inverted polarity through the inverting means;
• and
• address demodulating means for demodulating an address signal from an output from the signal level.