US2001041240A1PendingUtilityA1
Optical recording medium, recording material, method of producing optical recording medium, and optical recording, reading and rewriting method

Priority: Mar 31, 2000Filed: Mar 29, 2001Published: Nov 15, 2001
Est. expiryMar 31, 2020(expired)· nominal 20-yr term from priority
Inventors:Kazunori Ito Eiko Hibino Makoto Harigaya Takashi Hibaguchi Hajime Yuzurihara Nobuaki Onagi Hiroko Ohkura Katsuhiko Tani Noriyaki Iwata
G11B 7/243G11B 7/2534G11B 2007/24314G11B 7/00454G11B 2007/24316G11B 7/26G11B 7/268G11B 2007/24312G11B 2007/2431Y10T428/21G11B 2007/24308G11B 2007/24322
PatentIndex Score
Cited by
References
Claims
Abstract

An optical recording medium including a recording layer which includes a reversible phase-change recording material, the recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing the reversible phase change of the phase-change recording material, wherein when a recording mark formed in the recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1 ≦R≦2.0, in which R is δ repeat /δ 1 as defined in the specification, the optical recording medium satisfies a relationship of d 1 >d ow as defined in the specification. The phase-change recording material, a method producing the optical recording medium, and a method of writing information in the optical recording medium, reading written information therefrom and rewriting written information thereare are proposed.
Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . An optical recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material. 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,    wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1 ≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitter δ repeat  to said 1st reading jitter δ 1  is d (=δ repeat /δ 1 ).    said optical recording medium satisfies a relationship of d 1 &gt;d ow , in which d 1  is said jitter increasing ratio of an initial writing mark, and d ow  is a jitter increasing ratio of a 1000-times rewritten recording mark.    
     
     
         2 . The optical recording medium as claimed in    claim 1   , wherein said phase-change recording material comprises a psuedo binary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-Tem, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ce.    
     
     
         3 . The optical recording medium as claimed in    claim 2   , wherein the total content ratio A uL Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         4 . The optical recording medium as claimed in    claim 2   , wherein the contents of Sb and Te in terms of atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         5 . The optical recording medium as claimed in    claim 2   , wherein the content ratio B of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.01≦B≦0.07.  
     
     
         6 . The optical recording medium as claimed in    claim 2   , wherein said pseudo binary comrposition of said phase-change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         7 . The optical recording medium as claimed in    claim 6   , where in said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 0.60 to 0.80,    Te: 0.15 to 0.30,    Ge: 0,01 to 0.07,    Ag: 0.001 to 0.03, and    In: 0.02 to 0.09.    
     
     
         8 . A phase-change recording material for use in a recording layer of an optical recording medium, which phase-change recording material is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material, 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,    wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitter δ repeat  to said 1st reading jitter δ 1  is d (=δ repeat /δ 1 ),    said optical recording medium satisfies a relationship of d 1 &gt;d ow , in which d 1  is said jitter increasing ratio of an initial writing mark, and d 1  is a jitter increasing ratio of a 1000-times rewritten recording mark.    
     
     
         9 . The phase-change recording material as claimed in    claim 8   , wherein said phase-change recording material comprises a pseudo binary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.    
     
     
         10 . The phase-change recording material as claimed in    claim 9   , wherein the total content ratio A of Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         11 . The phase-change recording material as claimed in    claim 9   , wherein the contents of Sb and Te in terms of atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         12 . The phase-change recording material as claimed in    claim 9   , wherein the content ratio B of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.01≦B≦0.07.  
     
     
         13 . The phase-change recording material as claimed in    claim 9   , wherein said pseudo binary composition of said phase-change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         14 . The phase-change recording material as claimed in    claim 13   , wherein said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 0.60 to 0.80,    Te: 0.15 to 0.30,    Ge: 0.01 to 0.07,    Ag: 0.001 to 0.03, and    In: 0.02 to 0.09.    
     
     
         15 . A method of producing an optical recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phaso and vico versa by light irradiation of said phase-change recording material, 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,    wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitters to said 1st reading jitter δ 1  is d (=δ repeat /δ 1 ), said optical recording medium satisfies a relationship of d 1 &gt;d ow , which d 1  is said jitter increasing ratio of an initial writing mark, and d ow  is a jitter increasing ratio of a 1000-times rewritten recording mark, comprising the step of forming said recording layer by performing sputtering, using a target, with a sputtering power of 0.1 kW to 1.5 kW, said target being prepared by fusing and mixing a composition composed of a plurality of elements with a predetermined composition, crushing said composition to prepare a pulverized composition, and sintering said pulverized composition.    
     
     
         16 . The method as claimed in    claim 15   , wherein said phase-change recording material comprises a pseudo binary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.    
     
     
         17 . The method as claimed in    claim 16   , wherein the total content ratio A of Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         18 . The optical recording medium as claimed in    claim 16   , wherein the contents of Sb and Te in terms ot atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         19 . The method as claimed in    claim 16   , wherein the content ratio B of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase change recording material is in a range of 0.01≦B≦0.07.  
     
     
         20 . The method as claimed in    claim 16   , wherein said pseudo binary composition of said phase change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         21 . The method as claimed in    claim 20   , wherein said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 0.60 to 0.80,    Te: 0.15 to 0.30,    Ge: 0.01 to 0.07,    Ag: 0.001 to 0.03, and    In: 0.02 to 0.09.    
     
     
         22 . A method of producing an optical recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material, 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,    wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitter δ repeat  to said 1st reading jitter δ 1  is d (=δ repeat /δ 1 ), said optical recording medium satisfies a relationship of d 1 &gt;d ow , in which d 1  is said jitter increasing ratio of an initial writing mark, and d ow  is a jitter increasing ratio of a 1000-times rewritten recording mark, comprising the step of forming said recording layer by sputtering, using a target, with a sputtering pressure of 0.8 mTorr to 9 mTorr, said target being prepared by fusing and mixing a composition composed of elements with a predetermined composition, crushing said composition to prepare a pulverized composition, and sintering said pulverized composition.    
     
     
         23 . The method as claimed in    claim 22   , wherein said phase-change recording material comprises a pseudo binary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.    
     
     
         24 . The method as claimed in    claim 23   , wherein the total content ratio A of Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         25 . The method as claimed in    claim 23   , wherein the contents of Sb and Te in terms of atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         26 . The method as claimed in    claim 23   , wherein the content ratio B of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.01≦B≦0.07.  
     
     
         27 . The method as claimed in    claim 23   , wherein said pseudo binary composition of said phase-change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         28 . The method as claimed in    claim 27   , wherein said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 60 to 0.80,    Te: 0.15 to 0.30,    Ge: 0.01 to 0.07,    Ag: 0.001 to 0.03, and    In: 0.02 to 0.09.    
     
     
         29 . A method of producing an optical recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material, 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,    wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitter δ repeat  to said 1st readinq jitter δ 1  is d (=δ repeat /δ 1 ), said optical recording medium satisfies a relationship of d 1 &gt;d ow , in which d 1  is said jitter increasing ratio of an initial writing mark, and d ow  is a jitter increasing ratio of a 1000-times rewritten recording mark, comprising the step of forming said recording layer by performing sputtering, using a target, in a sputtering chamber with the pressure in said sputtering chamber being set at a vacuum degree of 9×10 −7  Torr or less immediately before said recording layer is formed, said target being prepared by fusing and mixing a composition composed of a plurality of elements with a predetermined composition, crushing said composition to prepare a pulverized composition, and sintering said pulverized composition.    
     
     
         30 . The method as claimed in    claim 29   , wherein said phase-change recording material comprises a pseudo biinary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.    
     
     
         31 . The method as claimed in    claim 30   , wherein the total content ratio A of Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         32 . The method as claimed in    claim 30   , wherein the contents of Sb and Te in terms of atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         33 . The method as claimed in    claim 30   , wherein the content ratio a of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material in a range of 0.01≦B≦0.07.  
     
     
         34 . The method as claimed in    claim 30   , wherein said pseudo binary composition of said phase-change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         35 . The method as claimed in    claim 34   , wherein said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 0.60 to 0.80,    Te: 0.15 to 030,    Ge: 0.01 to 0.07,    Ag: 0.001 to 0.03, and    In: 0.02 to 0.09.    
     
     
         36 . A method of writing information, reading written information, and rewriting written information in an optical recording medium with irradiating said optical recording medium with a laser beam with a spot diameter of 0.05 μm to 2.0 μm, said optical information recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material, 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,  
 wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitter δ repeat  to said 1st reading jitter δ 1  is d (=δ repeat /δ 1 ), said optical recording medium satisfies a relationship of d 1 &gt;d ow  in which d 1  is said jitter increasing ratio of an initial writing mark, and d ow  is a jitter increasing ratio of a 1000-times rewritten recording mark.  
 
     
     
         37 . The method as claimed in    claim 36   , wherein said phase-change recording material comprises a pseudo binary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represent by TeM, in which X represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.    
     
     
         38 . The method as claimed in    claim 37   , wherein the total content ratio A of Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         39 . The method as claimed in    claim 37   , wherein the contents of Sb and Te in terms of atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         40 . The method as claimed in    claim 37   , wherein the content ratio B of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.01≦B≦0.07.  
     
     
         41 . The method as claimed in    claim 37   , wherein said pseudo binary composition of said phase-change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         42 . The method as claimed in    claim 41   , wherein said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 0.60 to 0.80,    Te: 0.15 to 0.30,    Ge: 0.01 to 0.07,    Ag: 0.001 to 0.03, and    In: 0.02 to 0.09.    
     
     
         43 . A method of writing information, reading written information, and rewriting written information in an optical recording medium with irradiating said optical recording medium with a linear recording speed of 1.2 m/s to 25 m/s, said optical information recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material, 
 said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material,    wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000th repeated reading jitter δ repeat  of a recording mark to a 1st reading jitter δ 1  of said recording mark, namely R is δ repeat /δ 1 , and a jitter increasing ratio of said 5000th repeated reading jitter δ repeat  to said 1st reading jitter δ 1  is d (=δ repeat /δ 1 ), said optical recording medium satisfies a relationship of d 1 &gt;d ow , in which d 1  is said jitter increasing ratio of an initial writing mark, and d ow , is a jitter increasing ratio of a 1000-times rewritten recording mark.    
     
     
         44 . The method as claimed in    claim 43   , wherein said phase-change recording material comprises a pseudo binary composition, which has an NaCl-type crystal structure in the crystalline phase, wherein: 
 said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.    
     
     
         45 . The method as claimed in    claim 44   , wherein the total content ratio A of Sb and Te in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.80≦A≦0.97.  
     
     
         46 . The method as claimed in    claim 41   , wherein the contents of Sb and Te in terms of atomic ratio contained in said pseudo binary eutectic composition of said phase-change recording material satisfy a relationship of 0.65≦Sb/(Sb+Te)≦0.85.  
     
     
         47 . The method as claimed in    claim 44   , wherein the content ratio B of Ge in terms of atomic ratio contained in said pseudo binary composition of said phase-change recording material is in a range of 0.01≦B≦0.07.  
     
     
         48 . The method as claimed in    claim 44   , wherein said pseudo binary composition of said phase-change recording material further comprises as an additional element at least one element selected from the group consisting of Ag, In and Bi.  
     
     
         49 . The method as claimed in    claim 48   , wherein said pseudo binary composition of said phase-change recording material comprises Sb, Te, Ge, Ag, and In in the respective ranges of atomic ratio of: 
 Sb: 0.60 to 0.80,    Te: 0.15 to 0.30,    Ge: 0.01 to 0.07,    Ag; 0.001 to 0.03, and    In: 0.02 to 0.09.
Join the waitlist — get patent alerts

Track US2001041240A1 — get alerts on status changes and closely related new filings.
We store only your email — no account needed. See our privacy policy.