Source: http://www.google.com/patents/US5761179?dq=5,664,133
Timestamp: 2016-06-01 00:02:16
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Matched Legal Cases: ['art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1']

Patent US5761179 - Phase-change optical recording method using pulse width modulation technique - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsWhen recording data according to the PWM recording system by modulating signals, pulse modulation for pulse modulation for recording for recording a 0 signal or the like having a signal width of nT (T: Clock time) after modulation is a continuous electro-magnetic wave at a power level e, a record signal...http://www.google.com/patents/US5761179?utm_source=gb-gplus-sharePatent US5761179 - Phase-change optical recording method using pulse width modulation techniqueAdvanced Patent SearchPublication numberUS5761179 APublication typeGrantApplication numberUS 08/631,327Publication dateJun 2, 1998Filing dateApr 12, 1996Priority dateApr 14, 1909Fee statusPaidAlso published asDE69617372D1, DE69617372T2, DE69628499D1, DE69628499T2, DE69638266D1, EP0737962A2, EP0737962A3, EP0737962B1, EP0778565A1, EP0778565B1, EP1271488A2, EP1271488A3, EP1271488B1, EP1739661A2, EP1739661A3, EP1739661B1, US5740149Publication number08631327, 631327, US 5761179 A, US 5761179A, US-A-5761179, US5761179 A, US5761179AInventorsHiroko Iwasaki, Yukio Ide, Yoshiyuki Kageyama, Makoto Harigaya, Michiharu AbeOriginal AssigneeRicoh Company, LimitedExport CitationBiBTeX, EndNote, RefManPatent Citations (15), Non-Patent Citations (20), Referenced by (54), Classifications (40), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetPhase-change optical recording method using pulse width modulation technique
1. A pulse width modulation (PWM) data recording/regenerating method, comprising the steps of:providing a data recording medium comprising a recording layer; and irradiating the recording layer with an electromagnetic wave to generate a phase change therein, whereby data is selectively recorded in, or rewritten in, said recording layer, wherein, in thus transferring data to or from said data recording medium by modulating signals according to the PWM system, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (where T is clock time) after modulation is a continuous electromagnetic wave at a power level e, a record signal pulse array when recording or rewriting one signal having a signal width of "nT" (where n is an integer, and n≦1) after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total, n is an integer, and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total (where n' is also an integer, and n'≦n), and a pulse section op having a time width z and a power level d; x, y and z satisfy the relationships 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T; and also controls are provided so that the relationship (a and c)≧e≧(b and d) is satisfied, pulse modulation for recording when recording or rewriting a signal having a prespecified signal width after modulation is a continuous electromagnetic wave at a first power level, pulse modulation for recording pulse array when recording or rewriting a single signal having a prespecified signal width after modulation is an electromagnetic wave pulse array comprising a pulse section having a first time width and a second power level, a multi-pulse section in which low level pulses each at a third power level having a time width totally equal to a clock time and high level pulses each at a fourth power level alternately appear at a prespecified duty ratio prespecified times, and a pulse section having a second time width and a fifth power level, said first time width, said duty ratio, and said second time width are respectively set according to a linear speed. 2. The method according to claim 1, wherein:a system of modulating a signal to be recorded is one of an EFM modulating system or an improvement thereof, and n'=2. 3. The method according to claim 1, wherein:when regenerating data, a signal detected by a detecting means from the data recording medium is subjected to DC coupling according to m=(I1-I2)/I1�100 in which I1 indicates a high level in an output level of this DC coupling and I2 indicates a low level thereof are computed, and at least one of a and c is substantially decided according to this m. 4. The method according to claim 1, wherein:a signal detected by the detecting means when regenerating data from the data recording medium is subjected to an AC coupling according to &#946;=(S1+S2)/(S1-S2)�100 in which S1 indicates a high level and S2 indicates a low level in an output of the AC coupling and S1 and S2 are computed, and at least one of e, a and c is substantially decided according to this β. 5. The method according to claim 1, comprising the further step of:detecting an error, and deciding b and d substantially according to the error. 6. The method according to claim 1, wherein:a signal is selectively recorded and/or rewritten by controlling a power level of an electromagnetic wave so that β is not less than -2 and not more than 10. 7. The method according to claim 1, wherein:a signal is selectively recorded and/or rewritten by controlling a power level of an electromagnetic wave so that e/a or e/c is not less than 0.3 and not more than 0.7. 8. The method according to claim 1, wherein:x, y, z, and a power level of an electromagnetic wave for regenerating a signal are decided according to an amplitude of a reflected wave when data is regenerated from the data recording medium. 9. The method according to claim 1, wherein:the data recording medium is rotated at a rotational linear speed of not less than 1.2 m/s and not more than 5.6 m/s, where data is recorded therein. 10. The method according to claim 1, wherein:x satisfies the relationship 1 T≦x≦1.75 T. 11. The method according to claim 1, wherein:z satisfies the relationship 0.5 T≦z≦1 T. 12. The method according to claim 1, wherein:x, y and z satisfy the relationships 1 T≦x≦1.75 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T, respectively, when the data recording medium is moved at a standard linear speed for a compact disk. 13. A data recording/regenerating method, comprising the steps of:providing a data recording medium comprising a recording layer; and irradiating the recording layer with an electromagnetic wave to generate a phase change therein, whereby data is selectively recorded in, regenerated from, or rewritten in, said data recording layer, wherein, in thus transferring data to or from said data recording medium by modulating signals according to the PWM recording system, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT is a clock time) after modulation is a continuous electromagnetic wave at a power level e, pulse modulation for recording pulse array when recording or rewriting a signal having a signal width of nT (where n is an integer, and n≦1) after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total, and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total (where n' is also an integer, and n'-n), and a pulse section op having a time width z and a power level d,; x, y, and z satisfy the relationships 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T, respectively, and relationship (a and c)>e>(b and d). 14. The method according to claim 13, wherein:a system of modulating a signal to be recorded is one of an EFM modulating system or an improvement thereof, and n'=2. 15. The method according to claim 13, wherein:when regenerating data, a signal detected by a detecting means from the data recording medium is subjected to DC coupling according to m=(I1=I2)/I1�100 in which I1 indicates a high level and I2 indicates a low level in an output of the DC coupling, and I1 and I2 are computed, and at least one of a and c is substantially decided according to this m. 16. The method according to claim 13, wherein:a signal detected by the detecting means from the data recording medium when regenerating data from the data recording medium is subjected to AC coupling according to: &#946;=(S1+S2)/(S1-S2)�100, in which S1 indicates a high level and S2 indicates a low level in an output level of the AC coupling and S1 and S2 are computed, and at least one of e, a and c is substantially decided according to this β. 17. The method according to claim 13, comprising the further step of:detecting an error and deciding b and d substantially according to the error. 18. The method according to claim 13, wherein:a signal is selectively recorded and/or rewritten by controlling a power level of an electromagnetic wave so that β is not less than -2 and not more than 10. 19. The method according to claim 13, wherein:a signal is selectively recorded and/or rewritten by controlling a power level of an electromagnetic wave so that e/a or e/c is not less than 0.3 and not more than 0.7. 20. The method according to claim 13, wherein:x, y, z, and a power level of an electromagnetic wave for regenerating a signal are decided according to an amplitude of a reflected wave when data is regenerated from the data recording medium. 21. The method according to claim 13, wherein:the data recording medium is rotated at a rotational linear speed of not less than 1.2 m/s and not more than 5.6 m/s, where data is recorded therein. 22. The method according to claim 13, wherein:x satisfies the relationship 1 T≦x≦1.75 T. 23. The method according to claim 13, wherein:z satisfies the relationship 0.5 T≦z≦1 T. 24. The method according to claim 13, wherein:x, y and z satisfy the relationships 1 T≦x≦1.75 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T, respectively when the data recording medium is moved at a standard linear speed for a compact disk. 25. A data recording/regenerating apparatus in which, by irradiating an electromagnetic wave to a data recording medium to generate a phase change in a recording layer, data is recorded in and regenerated from said data recording medium, and in which rewriting of data is also possible, comprising:a recording means for recording data in a data recording medium by modulating signals according to a PWM recording system; and a recording control means for controlling said recording means,wherein, in recording data in said data recording medium by modulating signals according to the PWM recording system, pulse modulation for recording when recording or rewriting a signal having a prespecified signal width after modulation is a continuous electromagnetic wave at a first power level, and wherein pulse modulation for recording pulse array when recording or rewriting a signal having a prespecified signal width after modulation is an electromagnetic wave pulse array comprising a pulse section having a first time width and a second power level, a multi-pulse section in which low level pulses each at a third power level having a time width totally equal to a clock time and high level pulses each at a fourth power level alternately appear at a prespecified duty ratio prespecified times, and a pulse section having a second time width and a fifth power level, and wherein said recording control means sets said first time width, said duty ratio and said second time width, respectively, according to a linear speed. 26. The apparatus according to claim 25, wherein:said recording means modulates a signal to be recorded according to an EFM modulating system or an improvement thereof, and n'=2. 27. The apparatus according to claim 25, comprising:a detecting means for detecting a signal from said data recording medium when regenerating data from said data recording medium; a DC coupling means for subjecting a signal detected by the detecting means to a DC coupling; and a means for computing m=(I1-I2)/I1�100, from a high level I1 to a low level I2 in an output from the DC coupling means, and deciding at least one of a and c according to the computed m. 28. The apparatus according to claim 25, comprising:a detecting means for detecting a signal from the data recording medium when regenerating data from the data recording medium; an AC coupling means for subjecting a signal detected by the detecting means to an AC coupling; and a means for computing β=(S1+S2)/(S1-S2)�100, from a high level S1 to a low level S2 in an output level of the AC coupling, and deciding at least one of e, a and c substantially according to this β. 29. The apparatus according to claim 25, comprising:a means for detecting an error and deciding b and d substantially according to the error. 30. The apparatus according to claim 25, comprising:a means for selectively having a signal recorded and/or rewritten by controlling a power level of an electromagnetic wave so that β is not less than -2 and not more than 10. 31. The apparatus according to claim 25, comprising:a means for selectively having a signal recorded and/or rewritten by controlling a power level of an electromagnetic wave so that e/a and e/c are each not less than 0.3 and not more than 0.7. 32. The apparatus according to claim 25, comprising:a means for deciding x, y, z and a power level of an electromagnetic wave for regenerating a signal according to an amplitude of a reflected wave when regenerating data from the data recording medium. 33. The apparatus according to claim 25, wherein:the data recording medium is rotated at a rotational linear speed of not less than 1.2 m/s and not more than 5.6 m/s when data is recorded therein. 34. The apparatus according to claim 25, wherein:the data recording medium is rotated at a rotational linear speed of not less than 1.2 m/s and not more than 5.6 m/s where data is recorded therein. 35. The apparatus according to claim 25, comprising:a means for temporally storing therein a portion of data to be recorded. 36. The apparatus according to claim 25, comprising:a means for increasing a rotational linear speed of the data recording medium, when data is recorded therein, to a level higher than a rotational linear speed of the data recording medium when data is regenerated therefrom. 37. A data recording/regenerating apparatus in which, by irradiating an electromagnetic wave to a data recording medium to generate a phase change in a recording layer, data is recorded in and regenerated from said data recording medium, and in which rewriting of data is also possible, comprising:a recording means for recording data in said data recording medium by modulating signals according to a PWM recording system,wherein, in said recording means, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (where T is a clock time) after modulation is a continuous electromagnetic wave at a power level e, pulse modulation for recording a pulse array when recording or rewriting a signal having a signal width of nT after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d, wherein x, y, and z satisfy the relationships 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T, respectively, n' is an integer equal to or smaller than n; and relationships (a and c)>e>(b and d) are satisfied. 38. The apparatus according to claim 37, wherein:said recording means modulates a signal to be recorded according to an EFM modulating system or an improvement thereof, and n'=2. 39. The apparatus according to claim 37, comprising:a detecting means for detecting a signal from said data recording medium when regenerating data from said data recording medium; a DC coupling means for subjecting a signal detected by the detecting means to a DC coupling; and a means for computing m=(I1-I2)/I1�100 from a high level I1 to a low level I2 in an output level from the DC coupling means, and deciding at least one of a and c according to the computed m. 40. The apparatus according to claim 37, comprising:a detecting means for detecting a signal from the data recording medium when regenerating data from the data recording medium; an AC coupling means for subjecting a signal detected by this detecting means to an AC coupling; and a means for computing β=(S1+S2)/(S1-S2)�100 from a high level S1 to a low level S2 in an output of the AC coupling, and deciding at least one of e, a and c substantially according to the computed β. 41. The apparatus according to claim 37, comprising:a means for detecting an error and deciding b and d substantially according to the error. 42. The apparatus according to claim 37, comprising:a means for selectively having a signal recorded and/or rewritten by controlling a power level of an electromagnetic wave so that β is not less than -2 and not more than 10. 43. The apparatus according to claim 37, comprising:a means for selectively having a signal recorded and/or rewritten by controlling a power level of an electromagnetic wave so that e/a or e/c is not less than 0.3 and not more than 0.7. 44. The apparatus according to claim 37, comprising:a means for deciding x, y, z and a power level of an electromagnetic wave for regenerating a signal according to an amplitude of a reflected wave when regenerating data from the data recording medium. 45. The apparatus according to claim 37, wherein:the data recording medium is rotated at a rotational linear speed of not less than 1.2 m/s and not more than 5.6 m/s when data is recorded therein. 46. The apparatus according to claim 37, wherein:the data recording medium is rotated at a rotational linear speed of not less than 1.2 m/s and not more than 5.6 m/s, where data is recorded therein. 47. The apparatus according to claim 37, comprising:a means for temporally storing therein a portion of data to be recorded. 48. The apparatus according to claim 37, comprising:a means for increasing a rotational linear speed of the data recording medium, when data is recorded therein, to a level higher than a rotational linear speed of the data recording medium when data is regenerated therefrom. 49. The apparatus according to claim 37, wherein:said data recording medium further comprises at least one of a substrate and a heat-resisting protection layer. 50. The apparatus according to claim 49, wherein:the data recording medium further comprises a reflecting/radiating layer. 51. The apparatus according to claim 49, wherein:said heat-resisting protection layer is provided at both sides of said recording layer so that the heat-resisting protection layer holds the recording layer from the two sides. 52. The apparatus according to claim 49, wherein:a film thickness of said heat-resisting protection layer provided between said substrate and said recording layer is in a range from 500 to 2500 angstroms. 53. The apparatus according to claim 49, wherein:a film thickness of said heat-resisting protection layer is in a range from 100 to 1500 angstroms. 54. The apparatus according to claim 49, wherein:main constituent elements of said recording layer are Ag, In, Sb and Te. 55. The apparatus according to claim 49, wherein:a film thickness of said recording layer is in a range from 100 to 1000 angstroms. 56. The apparatus according to claim 49, wherein:said substrate is composed of at least one of glass, ceramics, or resin. 57. The apparatus according to claim 49, wherein:a material for said heat-resisting protection layer is a metallic oxide such as SiO, SiO2, ZnO, SnO2, Al2 O2, TiO2, In2 O2, MgO, or ZrO2 ; a nitride such as Si2 N4, AlN, TiN, BN, or ZrN; a sulfide such as ZnS, In2 S3, and TaS4 ; a carbide such as SiC, Tac, B4 C, WC, TiC, or ZrC; a diamond carbon or a mixture thereof. 58. The apparatus according to claim 49, wherein:said reflecting/radiating layer is composed of a metallic material selected from a group consisting of Al, Au, and an alloy thereof. 59. The apparatus according to claim 50,wherein:a film thickness of said reflecting/radiating layer is in a range from 300 to 2000 angstroms. 60. The method according to claim 1, wherein:said data recording medium comprises at least a substrate, a heat-resisting protection layer, and a recording layer. Description
The present invention relates to a data recording/regenerating method and a data recording/regenerating apparatus, for recording data in and regenerating data from a data recording medium such as a compact disk in which rewriting of data is possible, and a data recording medium for the same.
As one of data recording medium for recording data by irradiating the same with an electromagnetic wave, especially a laser beam, or for regenerating data or deleting data therefrom, a so-called phase change type of data recording medium making use of transition between a crystalline phase and a non-crystalline phase or between crystalline phases is well known. Especially in the phase change type of data recording medium, overwriting with a single beam is possible, which is difficult in an electrophoto-magnetic memory, memory. It is also simpler than an optical system for a drive system for recording, regenerating and deleting data in and from an electrophoto-magnetic disk, so that recently active researching efforts are made in this field.
pulse modulation for recording when recording or rewriting a 0 signal having a signal width of "nT" (where T is clock time) after modulation is a continuous electromagnetic wave at a power level "e", a record signal pulse array when recording or rewriting one signal having a signal width of "nT" (where "n" is an integer, and n≦1) after modulation is an electromagnetic wave pulse array comprising a pulse section "fp" having a time width "x" and a power level "a", a multi-pulse section mp in which lower level pulses at a power level "b" having a time width of "T" in total, "n" is an integer, and high power level pulses at a power level "c" alternately appear at a duty ratio of "y (n-n')" times in total (where "n'" is also an integer, and n'≦n), and a pulse section "op" having a time width "z" and a power level "d"; "x", "y", and "z" satisfy the relationships 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z ≦1 T; and also controls are provided so that the relationship (a and c)>e>(b and d) is satisfied,
In other words, in the data recording/regenerating method in which, by irradiating an electro-magnetic wave to a data recording medium to generate a phase change in a recording layer thereof, data is recorded in and regenerated from said data recording medium, and also in which rewriting of data is possible; when recording data in said data recording medium by modulating signals according to the PWM recording system, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (T: Clock time) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting one signal having a signal width of "nT" after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width "x" and a power level "a", a multi-pulse section mp in which lower level pulses at a power level "b" having a time width of "T" in total, "n" is an integer, and high power level pulses at a power level "c" alternately appear at a duty ratio of y "(n-n')" times in total, and a pulse section op having a time width "z" and a power level "d,"; "x", "y", and "z" satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T; "n'" is an integer equal to or smaller than n (n'≦n); and also controls are provided so that the relation of (a and c)>e>(b and d) is satisfied.
In the recording means, in recording data according to the PWM recording system, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (n: Prespecified value, T: Clock time: a time corresponding to a cycle of a clock used for modulation of a signal) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting 1 signal having a signal width of nT after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d; x, y, and z satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T; n is an integer not less than 1; n' is an integer equal to or smaller than n (n'≦n); and also the relation of (a and c)>e>(b and d) is satisfied. FIG. 1B is a view in a case of n'=1, FIG. 1C is a view in a case of n'=2, and FIG. 1D is a view in a case of n'=3.
As described above, in the data recording/regenerating method according to the present invention in which, by irradiating an electromagnetic wave to a data recording medium to generate a phase change in a recording layer, data is recorded in and regenerated from the data recording medium, and also in which data is writable; in recording data in the data recording medium by modulating signals according to the PWM recording system, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (T: Clock time) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting 1 signal having a signal width of nT after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d; x, y, and z satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T; n' is an integer equal to or smaller than n (n'≦n); and also the relation of (a and c)>e>(b and d) is satisfied, so that a signal of better quality can stably be recorded and rewritten in the method of recording data in the phase change type of data recording medium in the PWM recording system.
In the recording control means, by controlling the recording section, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (T: Clock time) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting 1 signal having a signal width of nT after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d; x, y, and z satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.8, and 0.5 T≦z≦1 T; n' is an integer equal to or smaller than n (n'≦n); and also the relation of (a and c)>e>(b and d) is satisfied; and at the same time a time width x, a duty ratio y, and a time width z are respectively set according to a linear speed.
In the data recording/regenerating apparatus according to the present invention in which, by irradiating an electromagnetic wave to a data recording medium to generate a phase change in a recording layer, data is recorded in and regenerated from the data recording medium, and also in which data is writable; the apparatus comprises a recording means for recording data in a data recording medium by modulating signals according to the PWM recording system, and a recording control means for controlling the recording means; and in the recording control means, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (T: Clock time) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting 1 signal having a signal width of nT after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d; x, y, and z satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.8, and 0.5 T≦z≦1 T; n' is an integer equal to or smaller than n (n'≦n); and also the relation of (a and c)>e>(b and d) is satisfied, so that a signal of better quality can stably be recorded and rewritten in the apparatus for recording data in the phase change type of data recording medium in the PWM recording system.
In the embodiment of the present invention, the data recording/regenerating apparatus comprises a detecting means for detecting a signal from a data recording medium when data is regenerated from a data recording medium; a DC coupling means for subjecting a signal detected by this detecting means to DC coupling; and a means for calculating m=I1-I2)/I1�100 from the high level I1 and low level I2 in an output level from this DC coupling means and substantially deciding a and/or c from this m, so that an optimal recording power can be obtained in an apparatus for recording data in a phase change type of data recording medium according to the PWM recording system.
Also in the data recording method according to the present invention, a material for the heat-resisting protection layer is a metallic oxide such as SiO, SiO2, ZnO, SnO2, Al2 O2, TiO2, In2 O2, MgO, or ZrO2 ; a nitride such as Si2 N4, AlN, TiN, BN, or ZrN; a sulfide such as ZnS, In2 S3, and TaS4 ; a carbide such as no SiC, Tac, B4 C, WC, TiC, or ZrC; a diamond carbon or a mixture thereof, so that it is possible to provide an optimal data recording medium for recording data in a phase change type of data recording medium according to the PWM recording system.
m0 =m0 (P0)
m (P)=km0 (P), P=qP0 k. q: Constants which are not zero. As clearly understood from the following expressions: ##EQU1## so far as the standardized gradation g (P) is monitored, always a value equal to the standard value g0 (P0) can be obtained.
FIG. 12 shows an example of effects provided in the embodiment of the invention. Relations between amplitude m of pulse modulation for recording recorded and regenerated by 3 types of data recording/regenerating apparatus each different from that according to this embodiment and the recording power P are as shown in FIG. 12, and a saturation value of amplitude of pulse modulation for recording in each case is different: 0.60, 0.75, and 0.50 respectively, so that different curves m (0), m (1) and m (2) are provided, and in this case a uniform target optimal recording power can not be obtained even with reference to a certain pulse modulation for recording amplitude level, and nonuniformity is generated in response to the curves m(o), m (1) and m (2). Furthermore if P is larger than 12 mW (P>12 mW), the three curves m (0), m (1) and m (2) are almost parallel to each other, so that it is impossible even to set a common reference for pulse modulation for recording level.
Also in the embodiment of the present invention, an x, y, z changing means for changing values of x, y and x according to a linear speed of a data recording medium are provided, so that an identical data according medium can be used in both the equal-speed mode in which the data recording medium is rotated at a rotational linear speed in a range from 1.2 to 1.4 m/s which is a reference speed for a compact disk and the double-speed mode in which the data recording medium is rotated at a rotational linear speed 2 times faster than the reference speed for a compact disk (in a range from 2.4 to 2.8 m/s). The x, y, z changing means sets values of x, y, z in the conditions of 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T respectively in the double speed mode, and in the conditions of 1 T≦x≦1.75 T, 0.4≦y≦0.60, and 0.5 T≦z≦1 T respectively in the equivalent speed mode.
In the data recording/regenerating apparatus in which, by irradiating an electromagnetic wave to a data recording medium to generate a phase change in a recording layer, data is recorded in and regenerated from the data recording medium, and also in which data is writable; the apparatus comprises a recording means for recording data in a data recording medium by modulating signals according to the PWM recording system, and a recording control means for controlling the recording means; and in the recording control means, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (T: Clock time) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting 1 signal having a signal width of nT (T: Clock time) after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d; x, y, and z satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.8, and 0.5 T≦z≦1 T; n' is an integer equal to or smaller than n (n'≦n); and also the relation of (a and c)>e>(b and d) is satisfied, so that a signal of better quality can stably be recorded and rewritten in the apparatus for recording data in the phase change type of data recording medium in the PWM recording system.
In the data recording/regenerating apparatus in which, by a irradiating an electro-magnetic wave to a data recording medium to generate a phase change in a recording layer, data is recorded in and regenerated from the data recording medium, and also in which data is writable; the apparatus has a recording means for recording data in the data recording medium by modulating signals according to the PWM recording system, and in the recording means, pulse modulation for recording when recording or rewriting a 0 signal having a signal width of nT (T: Clock time) after modulation is a continuous electromagnetic wave at a power level e; a record signal pulse array when recording or rewriting 1 signal having a signal width of nT (T: Clock time) after modulation is an electromagnetic wave pulse array comprising a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which lower level pulses at a power level b having a time width of T in total and high power level pulses at a power level c alternately appear at a duty ratio of y (n-n') times in total, and a pulse section op having a time width z and a power level d; x, y, and z satisfy the relations of 0.5 T≦x≦2 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T; n' is an integer equal to or smaller than n (n'≦n); and also the relation of (a and c)>e>(b and d) is satisfied, so that a signal of better quality can stably be recorded and rewritten in the method of recording data in the phase change type of data recording medium in the PWM recording system.
In the data recording medium according to the present invention, a material for the heat-resisting protection layer is a metallic oxide such as SiO, SiO2, ZnO, SnO2, Al2 O2, TiO2, In2 O2, MgO, or ZrO2, a nitride such as Si2 N4, AlN, TiN, BN, or ZrN; a sulfide such as ZnS, In2 S3, and TaS4 ; a carbide such as SiC, Tac, B4 C, WC, TiC, or ZrC; a diamond carbon or a mixture thereof, and for this reason it is possible to provide a data recording medium optimal for recording data in the phase change type of data recording medium in the PWM recording system.
In the data recording/regenerating method according to the present invention, x, y and z satisfy the relations of 1 T≦x≦1.75 T, 0.4≦y≦0.6, and 0.5 T≦z≦1 T respectively when the data recording medium is moved at a standard linear speed for a compact disk, so that a signal of a better quality can stably be recorded and rewritten in the method of recording data in the phase change type of data recording medium in the PWM recording system, and also all the recording section can finely and stably be recorded and rewritten when the data recording medium is moved at a standard linear speed for a compact disk and also when the data recording medium is moved at a speed twice as fast as the standard linear speed for a compact disk.
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