Optical disc and manufacturing method for the same

A method for manufacturing an optical disc having a plurality of data recording layers including a recording film for recording data, comprising:

• supplying a substrate;
• coating the substrate with a photosensitive material;
• recording a pattern containing guide grooves in the substrate using a laser beam recorder with a recording beam wavelength of 230 nm or longer;
• developing the substrate to produce a master plate having the recorded pattern;
• duplicating a stamper based on the master plate, and producing a substrate layer with guide grooves at a track pitch of 0.36 μm or less on one side based on the stamper;
• laminating a data recording layer having a recording film on the substrate layer;
• and
• laminating a transparent layer that is substantially transparent to a thickness of 0.3 mm or less on the data recording layer for passing light emitted to the data recording layer;
• the guide grooves being formed on the substrate layer so that the groove width of the guide groove formed on the substrate layer is wider than the groove width of the guide groove of the recording film formed according to the guide grooves on the substrate layer, and is within 50% to 80% of the track pitch.

An optical disc recordable and reproducible using 390 nm to 450 nm wavelength light emitted from a read/write head having an objective lens with a numerical aperture of 0.7 or greater, comprising:

• a plurality of substrate layers each having guide grooves at a track pitch of 0.36 μm or less, the thickness of at least one layer being 0.3 mm or less;
• a plurality of data recording layers laminated onto the substrate layer for recording data to guide grooves in a recording film formed according to the guide grooves of the substrate layer;
• and
• an adhesive layer for bonding the plurality of data recording layers in mutual opposition;
• the groove width of the guide grooves formed on each of the plurality of substrate layers being wider than the groove width of guide grooves of each of the plurality of recording films and within 50% to 80% of the track pitch.

A method for manufacturing an optical disc having a plurality of data recording layers each including a recording film for recording data, comprising:

• supplying a plurality of substrates;
• coating each of the plurality of substrates with a photosensitive material;
• recording a pattern containing guide grooves in each of the plurality of substrates using a laser beam recorder with a recording beam wavelength of 230 nm or longer;
• developing each of the plurality of substrates to produce a plurality of master plates having the recorded pattern;
• duplicating a plurality of stampers based on each of the plurality of master plates, and producing a plurality of substrate layers based on the stampers, each substrate layer having on one side thereof guide grooves with a track pitch of 0.36 μm or less;
• laminating a data recording layer having a recording film on each of the plurality of substrate layers;
• and
• bonding the plurality of data recording layers together by way of an intervening substantially transparent adhesive layer;
• the guide grooves being formed on each of the plurality of substrate layers so that the groove width of the guide grooves formed on each substrate layer is wider than the groove width of the guide grooves of a recording film formed according to the guide groove of each substrate layer, and is within 50% to 80% of the track pitch.

An optical disc recordable and reproducible using 390 nm to 450 nm wavelength light emitted from a read/write head having an objective lens with a numerical aperture of 0.7 or greater, comprising:

• a substrate layer having first guide grooves at a track pitch of 0.36 μm or less;
• a first data recording layer containing a recording film, laminated to the substrate layer for recording data to a second guide groove of a recording film formed according to the first guide groove of the substrate layer;
• an intermediate layer that is a substantially transparent intermediate layer laminated to the first data recording layer for passing light emitted to the first data recording layer, and having third guide grooves with a track pitch of 0.36 μm or less on the side opposite the data recording layer;
• a second data recording layer laminated onto the intermediate layer and including a recording film for recording data to fourth guide grooves of the recording film formed according to the third guide grooves of the intermediate layer;
• and
• a transparent resin layer laminated onto the second data recording layer, the transparent resin layer being substantially transparent with a thickness of 0.3 mm or less for passing the emitted light;
• the groove width of the first guide groove being wider than the groove width of the second guide groove,
• the groove width of the third guide groove being wider than the groove width of the fourth guide groove, and
• the groove width of the first guide groove and the groove width of the third guide groove being within 50% to 80% of the track pitch.

A method for manufacturing an optical disc having a plurality of data recording layers each including a recording film for recording data, comprising:

• supplying a substrate;
• coating the substrate with a photosensitive material;
• recording a pattern containing guide grooves in the substrate using a laser beam recorder with a recording beam wavelength of 230 nm or longer;
• developing the substrate to produce a master plate having the recorded pattern;
• duplicating a stamper based on the master plate, and producing a substrate layer with first guide grooves at a track pitch of 0.36 μm or less on one side based on the stamper;
• laminating a first data recording layer having a recording film on the substrate layer and forming second guide grooves corresponding to the first guide grooves on the recording film;
• laminating a substantially transparent intermediate layer made from a UV setting resin on the first data recording layer for passing light emitted to the first data recording layer, disposing third guide grooves with a track pitch of 0.36 μm or less to the side of the intermediate layer opposite the first data recording layer of the intermediate layer based on a stamper having substantially the same guide groove pattern as the first stamper;
• laminating a second data recording layer having a recording film on the intermediate layer and forming fourth guide grooves corresponding to the first guide grooves on the recording film;
• and
• laminating a transparent resin layer that is substantially transparent and 0.3 mm or less thick on the second data recording layer for passing the emitting light;
• the groove width of the first guide groove being wider than the groove width of the second guide groove,
• the groove width of the third guide groove being wider than the groove width of the fourth guide groove, and
• the groove width of the first guide groove and the groove width of the third guide groove being from 50% to 80% of the track pitch.