US 2001/0017833 A1Published application

Method of recording and reproducing information and apparatus for recording and reproducing information using the method

AssigneeRicoh Company, Ltd.

InventorsKatsuyuki Yamada, Yuki Nakamura, Masaki Kato

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Abstract

A method of recording and reproducing information in a phase-change optical recording medium by irradiation of an electromagnetic wave for recording, reproducing and/or rewriting information is proposed, wherein when information is recorded in the phase-change optical recording medium by modulating an input signal and conducting pulse width modulation recording, a recording pulse string for recording and rewriting is a continuous electromagnetic wave, and a recording pulse string for input signal, is an electromagnetic wave pulse string having a front-pulse portion fp, a multi-pulse portion mp with a total pulse duration period T and a duty ratio y, and an off-pulse portion op, wherein the duty ratio y is decreased as a recording linear velocity for the phase-change change optical recording medium is increased, whereby multi-speed recording or CAV (constant angular velocity) recording is carried out. An information recording and reproducing apparatus, using the above method, is also proposed.

Claims20

Dependent claims

A method of recording and reproducing information in a phase-change optical recording medium comprising a recording layer which comprises a phase-changeable recording material capable of being subjected to a phase-change by irradiation of an electromagnetic wave for recording, reproducing and/or rewriting information, wherein when information is recorded in said phase-change optical recording medium by modulating an input signal and conducting pulse width modulation recording,

(A) a recording pulse string for recording and rewriting, corresponding to a zero (0) signal with a signal width nT, in which n is a positive integer, and T is a clock unit time, after the modulation of said input signal, is a continuous electromagnetic wave with a power level e, and
(B) a recording pulse string for recording and rewriting, corresponding to a one (1) signal with a signal width nT, in which n is a positive integer, and T is a clock unit time, after the modulation of said input signal, is an electromagnetic wave pulse string having;
a front-pulse portion fp with a power level a and a pulse duration period x,
a multi-pulse portion mp comprising a low level pulse with a power level b and a high-level pulse with a power level c, with a total pulse duration period T and a duty ratio y, alternately repeating (n-n′) times continuously, and
an off-pulse portion op with a power level d and a pulse duration period z, in which x, y and z respectively satisfy 0.5T≦y≦2.0T, 0.125≦y≦0.875, and 0.125T ≦z≦1.0T, n′ is a positive integer which satisfies the condition of n′≦n, and (a and c) ≧e≧ (b and d), wherein said duty ratio y is decreased as a recording linear velocity for said phase-change optical recording medium is increased, whereby multi-speed recording or CAV (constant angular velocity) recording is carrier out.

2 more elements

An information recording and reproducing apparatus for recording and reproducing information by a method of recording and reproducing information in a phase-change optical recording medium comprising a recording layer which comprises a phase-changeable recording material capable of being subjected to a phase-change by irradiation of an electromagnetic wave for recording, reproducing and/or rewriting information, wherein when information is recorded in said phase-change optical recording medium by modulating an input signal and conducting pulse width modulation recording,

(A) a recording pulse string for recording and rewriting, corresponding to a zero (0) signal with signal width nT, in which n is a positive integer, and T is a clock unit time, after the modulation of said input signal, is a continuous electromagnetic wave with a power level e, and
(B) a recording pulse string for recording and rewriting, corresponding to a one (1) signal with A signal width nT, in which n is a positive integer, and T is a clock unit time, after the modulation of said input signal, is an electromagnetic wave pulse string having:
a front-pulse portion fp with a power level a and a pulse duration period x,
a multi-pulse portion mp comprising a low-level pulse with a power level b and a high-level pulse with a power level c, with a total pulse duration period T and a duty ratio y, alternately repeating (n-n′) times continuously, and
an off-pulse portion op with a power level d and a pulse duration period z, in which x, y and z respectively satisfy 0.5T≦x≦2.0T, 0.125≦y≦0.875, and 0.125T ≦z≦1.0T, n′ is a positive integer which satisfies the condition of n′≦n, and (a and c) ≧e≧ (b and d) , wherein said duty ratio y is decreasing as a recording linear velocity for said phase-change optical recording medium is increased, whereby multi-speed recording or CAV (constant angular velocity) recording is carried out.

2 more elements

Dependencies are inferred from the claim text.