Optical information recording medium and method for producing the same, method for recording and reproducing information thereon and recording/reproducing apparatus

A method for producing an optical information recording medium comprising:

• forming a first information layer on a transparent substrate;
• forming a second information layer on a protective substrate;
• and
• attaching the transparent substrate and the protective substrate via a separating layer, thereby forming the first information layer, the separating layer and the second information layer on the transparent substrate in this order,
• wherein as the second information layer, a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, an intermediate layer and a reflective layer are formed in this order from a side near the transparent substrate,
• wherein, of the upper protective layer, the intermediate layer and the reflective layer, a heat conductivity of a layer closest to the recording layer is a smallest of the three layers, and heat conductivities of the others of the three layers increase with increasing distance from the recording layer, and
• a thickness of the recording layer is from 4 nm to 14 nm.

A method for producing an optical information recording medium comprising:

• forming a first information layer on a transparent substrate;
• forming a second information layer on a protective substrate;
• and
• attaching the transparent substrate and the protective substrate via a separating layer, thereby forming the first information layer, the separating layer and the second information layer on the transparent substrate in this order,
• wherein as the second information layer, a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer are formed in this order from a side near the transparent substrate,
• a difference Δn=n1−n2 between a refractive index n1 of the light absorption layer and a refractive index n2 of the reflective layer at a wavelength λ of the light beams is 2 to 6, and
• a thickness of the reflective layer is not smaller than a thickness of the light absorption layer.

A method for producing an optical information recording medium comprising:

• forming a first information layer on a transparent substrate;
• forming a second information layer on a protective substrate;
• and
• attaching the transparent substrate and the protective substrate via a separating layer, thereby forming the first information layer, the separating layer and the second information layer on the transparent substrate in this order,
• wherein as the second information layer, a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer are formed in this order from a side near the transparent substrate, and
• the light absorption layer is formed so that 0.1 λ/(n1·k)≦d1≦1.0 λ/(n1·k1) is satisfied, where d1 is a thickness of the light absorption layer, λ is a wavelength of the light beams, and n1 and k1 are a refractive index and an extinction coefficient, respectively, of the light absorption layer at the wavelength λ.

A method for recording and reproducing an optical information recording medium comprising a transparent substrate and a multi-layered film formed on the transparent substrate, the multi-layered film including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, an intermediate layer and a reflective layer in this order from a side near the transparent substrate, wherein, of the upper protective layer, the intermediate layer and the reflective layer, a heat conductivity of a layer closest to the recording layer is a smallest of the three layers, and heat conductivities of the others of the three layers increase with increasing distance from the recording layer, and a thickness of the recording layer is from 4 nm to 14 nm,

• wherein when an intensity of the light beams is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• at least one recording mark to be recorded in the recording layer is formed with a recording pulse train consisting of a group of pulses generated by modulating the light beams between the power levels P1 and P3,
• when the recording mark is not to be recorded, the light beams are maintained at the power level P2, and
• information recorded in the recording layer is reproduced by irradiating the light beams at the power level P0.

A method for recording and reproducing an optical information recording medium comprising a transparent substrate and a multi-layered film formed on the transparent substrate, the multi-layered film including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, wherein a difference Δn=n1−n2 between a refractive index n1 of the light absorption layer and a refractive index n2 of the reflective layer at a wavelength A of the light beams is 2 to 6, and a thickness of the reflective layer is not smaller than a thickness of the light absorption layer,

• wherein when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P1≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• at least one recording mark to be recorded in the recording layer is formed with a recording pulse train consisting of a group of pulses generated by modulating the light beams between the power levels P1 and P3,
• when the recording mark is not to be recorded, the light beams are maintained at the power level P2, and
• information recorded in the recording layer is reproduced by irradiating the light beams at the power level P0.

A method for recording and reproducing an optical information recording medium comprising a transparent substrate and a multi-layered film formed on the transparent substrate, the multi-layered film including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, wherein the light absorption layer has a thickness d1 in a range of 0.1 λ/(n1·k1)≦d1≦1.0 λ/(n1·k1), where λ is a wavelength of the light beams, and n1 and k1 are a refractive index and an extinction coefficient, respectively, of the light absorption layer at the wavelength λ, wherein

• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P1>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• at least one recording mark to be recorded in the recording layer is formed with a recording pulse train consisting of a group of pulses generated by modulating the light beams between the power levels P1 and P3,
• when the recording mark is not to be recorded, the light beams are maintained at the power level P2, and
• information recorded in the recording layer is reproduced by irradiating the light beams at the power level P0.

A method for recording and reproducing an optical information recording medium comprising a transparent substrate and, on the transparent substrate, a first information layer, a separating layer and a second information layer in this order from a side near the transparent substrate, the first information layer including a first recording layer, the second information layer including a lower protective layer, a second recording layer, an upper protective layer, an intermediate layer and a reflective layer in this order from a side near the transparent substrate, the first and second recording layers changing reversibly between different states detectable optically by irradiation of light beams, wherein, of the upper protective layer, the intermediate layer and the reflective layer, a heat conductivity of a layer closest to the recording layer is a smallest of the three layers, and heat conductivities of the others of the three layers increase with increasing distance from the recording layer, and a thickness of the recording layer is from 4 nm to 14 nm,

• wherein the light beams is incident from a side of the transparent substrate so as to change a state of the first recording layer and the second recording layer, and
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≦P3≦0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• at least one recording mark to be recorded in the recording layer is formed with a recording pulse train consisting of a group of pulses generated by modulating the light beams between the power levels P1 and P3,
• when the recording mark is not to be recorded, the light beams are maintained at the power level P2, and
• information recorded in the recording layer is reproduced by irradiating the light beams at the power level P0.

A method for recording and reproducing an optical information recording medium comprising a transparent substrate and, on the transparent substrate, a first information layer, a separating layer and a second information layer in this order from a side near the transparent substrate, a first information layer including a first recording layer, the second information layer including a lower protective layer, a second recording layer, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, the first and second recording layers changing reversibly between different states detectable optically by irradiation of light beams, wherein a difference Δn=n1−n2 between a refractive index n1 of the light absorption layer and a refractive index n2 of the reflective layer is 2 to 6, and a thickness of the reflective layer is not smaller than a thickness of the light absorption layer,

• wherein the light beams is incident from a side of the transparent substrate so as to change a state of the first recording layer and the second recording layer, and
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• at least one recording mark to be recorded in the recording layer is formed with a recording pulse train consisting of a group of pulses generated by modulating the light beams between the power levels P1 and P3,
• when the recording mark is not to be recorded, the light beams are maintained at the power level P2, and
• information recorded in the recording layer is reproduced by irradiating the light beams at the power level P0.

A method for recording and reproducing an optical information recording medium comprising a transparent substrate and, on the transparent substrate, a first information layer, a separating layer and a second information layer in this order from a side near the transparent substrate, the first recording layer including a first recording layer, the second information layer including a lower protective layer, a second recording layer, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, the first and second recording layers changing reversibly between different states detectable optically by irradiation of light beams, wherein the light absorption layer has a thickness d1 in a range of 0.1 λ/(n1·k1)≦d1≦1.0 λ/(n1·k1), where λ is a wavelength of the light beams, and n1 and k1 are a refractive index and an extinction coefficient, respectively, of the light absorption layer at the wavelength λ,

• wherein the light beams is incident from a side of the transparent substrate so as to change a state of the first recording layer and the second recording layer, and
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• at least one recording mark to be recorded in the recording layer is formed with a recording pulse train consisting of a group of pulses generated by modulating the light beams between the power levels P1 and P3,
• when the recording mark is not to be recorded, the light beams are maintained at the power level P2, and
• information recorded in the recording layer is reproduced by irradiating the light beams at the power level P0.

An apparatus for recording and reproducing an optical information recording medium comprising an optical information recording medium, a light beam generator for generating light beams with which the optical information recording medium is irradiated, and a light beam intensity modulator for modulating an intensity of the light beams,

• wherein the optical information recording medium includes a transparent substrate and a multi-layered film formed on the substrate, the multi-layered film including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, an intermediate layer and a reflective layer in this order from a side near the transparent substrate, wherein, of the upper protective layer, the intermediate layer and the reflective layer, a heat conductivity of a layer closest to the recording layer is a smallest of the three layers, and heat conductivities of the others of the three layers increase with increasing distance from the recording layer, and a thickness of the recording layer is from 4 nm to 14 nm,
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P2≧0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• in the case where information is recorded by forming a recording mark in the recording layer, the light beam intensity modulator modulates the light beams between the power levels P1 and P3, so as to generate a recording pulse train consisting of a group of pulses, thereby forming at least one recording mark, and when the recording mark is not to be recorded, the light beam intensity modulator maintains the intensity of the light beams at the power level P2, and
• in the case where the information recorded in the recording layer is reproduced, the light beam intensity modulator maintains the intensity of the light beams at the power level P0.

An apparatus for recording and reproducing an optical information recording medium comprising an optical information recording medium, a light beam generator for generating light beams with which the optical information recording medium is irradiated, and a light beam intensity modulator for modulating an intensity of the light beams,

• wherein the optical information recording medium includes a transparent substrate and a multi-layered film formed on the transparent substrate, the multi-layered film including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, wherein a difference Δn=n1−n2 between a refractive index n1 of the light absorption layer and a refractive index n2 of the reflective layer at a wavelength λ of the light beams is 2 to 6, and a thickness of the reflective layer is not smaller than a thickness of the light absorption layer,
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P1 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• in the case where information is recorded by forming a recording mark in the recording layer, the light beam intensity modulator modulates the light beams between the power levels P1 and P3, so as to generate a recording pulse train consisting of a group of pulses, thereby forming at least one recording mark, and when the recording mark is not to be recorded, the light beam intensity modulator maintains the intensity of the light beams at the power level P2, and
• in the case where the information recorded in the recording layer is reproduced, the light beam intensity modulator maintains the intensity of the light beams at the power level P0.

An apparatus for recording and reproducing an optical information recording medium comprising an optical information recording medium, a light beam generator for generating light beams with which the optical information recording medium is irradiated, and a light beam intensity modulator for modulating an intensity of the light beams,

• wherein the optical information recording medium includes a transparent substrate and a multi-layered film formed on the transparent substrate, the multi-layered film including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, wherein the light absorption layer has a thickness d1 in a range of 0.1 λ/(n1·k1)≦d1≦1.0 λ/(n1·k1), where λ is a wavelength of the light beams, and n1 and k1 are a refractive index and an extinction coefficient, respectively, of the light absorption layer at the wavelength λ,
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• in the case where information is recorded by forming a recording mark in the recording layer, the light beam intensity modulator modulates the light beams between the power levels P1 and P3, so as to generate a recording pulse train consisting of a group of pulses, thereby forming at least one recording mark, and when the recording mark is not to be recorded, the light beam intensity modulator maintains the intensity of the light beams at the power level P2, and
• in the case where the information recorded in the recording layer is reproduced, the light beam intensity modulator maintains the intensity of the light beams at the power level P0.

An apparatus for recording and reproducing an optical information recording medium comprising an optical information recording medium, a light beam generator for generating light beams with which the optical information recording medium is irradiated, and a light beam intensity modulator for modulating an intensity of the light beams,

• wherein the optical information recording medium includes a transparent substrate and, on the transparent substrate, a first information layer, a separating layer and a second information layer in this order from a side near the transparent substrate, the second information layer including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, an intermediate layer and a reflective layer in this order from a side near the transparent substrate, wherein, of the upper protective layer, the intermediate layer and the reflective layer, a heat conductivity of a layer closest to the recording layer is a smallest of the three layers, and heat conductivities of the others of the three layers increase with increasing distance from the recording layer, and a thickness of the recording layer is from 4 nm to 14 nm,
• wherein the light beam generator is provided on the side of the transparent substrate,
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0≧0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• in the case where information is recorded by forming a recording mark in the recording layer, the light beam intensity modulator modulates the light beams between the power levels P1 and P3, so as to generate a recording pulse train consisting of a group of pulses, thereby forming at least one recording mark, and when the recording mark is not to be recorded, the light beam intensity modulator maintains the intensity of the light beams at the power level P2, and
• in the case where the information recorded in the recording layer is reproduced, the light beam intensity modulator maintains the intensity of the light beams at the power level P0.

An apparatus for recording and reproducing an optical information recording medium comprising an optical information recording medium, a light beam generator for generating light beams with which the optical information recording medium is irradiated, and a light beam intensity modulator for modulating an intensity of the light beams,

• wherein the optical information recording medium includes a transparent substrate and, on the transparent substrate, a first information layer, a separating layer and a second information layer in this order from a side near the transparent substrate, the second information layer including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, wherein a difference Δn=n1−n2 between a refractive index n1 of the light absorption layer and a refractive index n2 of the reflective layer is 2 to 6, and a thickness of the reflective layer is not smaller than a thickness of the light absorption layer,
• wherein the light beam generator is provided on the side of the transparent substrate,
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P3≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0≧0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• in the case where information is recorded by forming a recording mark in the recording layer, the light beam intensity modulator modulates the light beams between the power levels P1 and P3, so as to generate a recording pulse train consisting of a group of pulses, thereby forming at least one recording mark, and when the recording mark is not to be recorded, the light beam intensity modulator maintains the intensity of the light beams at the power level P2, and
• in the case where the information recorded in the recording layer is reproduced, the light beam intensity modulator maintains the intensity of the light beams at the power level P0.

An apparatus for recording and reproducing an optical information recording medium comprising an optical information recording medium, a light beam generator for generating light beams with which the optical information recording medium is irradiated, and a light beam intensity modulator for modulating an intensity of the light beams,

• wherein the optical information recording medium includes a transparent substrate and, on the transparent substrate, a first information layer, a separating layer and a second information layer in this order from a side near the transparent substrate, the second information layer including a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, a light absorption layer and a reflective layer in this order from a side near the transparent substrate, wherein the light absorption layer has a thickness d1 in a range of 0.1 λ/(n1·k1)≦d1≦1.0 λ/(n1·k1), where λ is a wavelength of the light beams, and n1 and k1 are a refractive index and an extinction coefficient, respectively, of the light absorption layer at the wavelength λ,
• wherein the light beam generator is provided on the side of the transparent substrate,
• when an intensity of the light beam is represented by power level P1 that can melt an irradiated portion instantly, power levels P2 and P3 (where P1>P2≧P1≧0) that cannot melt an irradiated portion instantly, and power level P0 (where P1>P0>0) that does not change an optical state of a recording mark and provides reflected beams sufficient to reproduce the recording mark by irradiation,
• in the case where information is recorded by forming a recording mark in the recording layer, the light beam intensity modulator modulates the light beams between the power levels P1 and P3, so as to generate a recording pulse train consisting of a group of pulses, thereby forming at least one recording mark, and when the recording mark is not to be recorded, the light beam intensity modulator maintains the intensity of the light beams at the power level P2, and
• in the case where the information recorded in the recording layer is reproduced, the light beam intensity modulator maintains the intensity of the light beams at the power level P0.