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EP0217293A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Use of compositions as reversible optical information media

Assignee: Panasonic Holdings Corp
•
Filing: 1986-09-25
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Granted: —
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Expires: 2006-09-25
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Abstract

Abstract Phase-change type, reversible optical infor­mation recording medium, being possible for recording, reproducing, erasing, and rewriting of information, by use of a laser beam. This invention consists of recording thin film of ternary compositions, for example, containing Ge, Te, Sb /or Bi or quaternary compositions containing the fourth element of Se with which a part of Te is replaced, which is established on such surface -­flat substrates as glass or plastics. In this case, the component ratio of Te and Se is selected not to be in excess for other elements, such as Ge, Sb /or Bi so as to be fixed as stable compounds of stoichiometric composi­tions of GeTe, Sb₂Te₃ /or Bi₂Te₃, or GeSe, Sb₂Se₃ /­Bi₂Se₃ when crystallized. Strictly speaking, a concentra­tion of each component is selected to have proper ratio of the number of atoms relative to each other so as to represent whole composition as the sum of each component. By this treatment, it is possible to have high crystallization speed and long cyclability of recording/erasing. The effect of Se is to increase the viscosity of the system and to make easily to obtain amorphous state; and moreover, by selecting of proper amount replaced with Te, it is possible to obtain the composition of recording film superior in both characteristics of recording (amorphiza­tion) and erasing (crystallization).

Inventors

  • 👤 Noboru Yamada
  • 👤 Kunio Kimura
  • 👤 Masatoshi Takao
  • 👤 Susumu Sanai

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-01 17:06
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/243; G11B7/2433; G11B2007/24302; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B7/004; G11B7/0045; G11B7/00454; G11B7/252; G11B7/253; G11B7/2531; G11B7/2533; G11B7/257; G11B7/26; G11B7/266; Y; Y10; Y10S; Y10S430/00; Y10S430/146

Claims Analysis

Total Claims: 17
Claim 1
Independent Claim 68 words
An optical information recording medium having a substrate and a recording thin film which produces reversible phase transition between amorphous and crystalline states by laser beam irradiation on said substrate, and said recording thin film is characterized by a) having a crystalline phase containing plural stoichiometric compounds of Te or Se as main components, and b) existing at least one stoichiometric stable compound among said plural stoichiometric phases.
Claim 2
Dependent Claim 68 words
An optical information recording medium having a substrate and a recording thin film which produces reversible phase transition between amorphous and crystalline states by laser beam irradiation on said substrate, and said recording thin film is characterized by a) having a crystalline phase containing plural stoichiometric compounds of Te or Se as main components, and b) existing at least one stoichiometric stable compound among said plural stoichiometric phases.
Claim 3
Dependent Claim 21 words
An optical information recording medium accord­ing to claim l, characterized by forming a metastable single phase at first state in crystallization.
Claim 4
Dependent Claim 18 words
An optical information recording medium according to claim 2, characterized by metastable phase with well symmetrized crystal structure.
Claim 5
Dependent Claim 23 words
An optical information-recording medium accord­ing to claim l, characterized by Te-compounds of Ge and Sb /or Bi as components consisting of crystal phase.
Claim 6
Dependent Claim 25 words
An optical information-recording medium according to claim l, characterized by Te-compounds and Se-compounds of Ge and Sb /or Bi as components consisting of crystal phase.
Claim 7
Dependent Claim 81 words
An optical information-recording medium according to claims l and 4, characterized by Te, Ge and Sb /or Bi as main components in the composition of recording film, and existence of the ratio of the numbers of atoms in the area, which is surrounded by the composition points of A₁ (Te₃₈,Ge₅₉, Sb /or Bi₃), B₁ (Te₅₀, Ge₂, Sb /or Bi₄₈), C₁ (Te₇₀, Ge₂, Sb /or Bi₂₈), and D₁ (Te₆₃, Ge₃₄, Sb /or Bi₃) in a triangle diagram showing the range of composition.
Claim 8
Dependent Claim 76 words
An optical information-recording medium according to claims l and 6, characterized by existence of the ratio of the numbers of Te, Ge and Sb /or Bi atoms in the area, which is surrounded by the composition points of A₂ (Te₄₂, Ge₅₅, Sb /or Bi₃), B₂ (Te₅₃, Ge₂, Sb /or Bi₄₅), C₂ (Te 64.5 , Ge₂, Sb /or Bi 33.5 ), and D₂ (Te₅₇, Ge₄₀, Sb /or Bi₃) in a triangle diagram showing the range of composition.
Claim 9
Dependent Claim 76 words
An optical information-recording medium according to claims l and 7, characterized by existence of the ratio of the numbers of Te, Ge and Sb /or Bi atoms in the area, which is surrounded by the composition points of A₃ (Te 44.5 , Ge 52.5 , Sb /or Bi₃), B3 (Te₅₅, Ge₂, Sb /or Bi₄₃), C₃ (Te₆₃, Ge₂, Sb /or Bi₃₅), and D₃ (Te₅₄, Ge₄₃, Sb /or Bi₃) in a triangle diagram showing the range of composition.
Claim 10
Dependent Claim 79 words
An optical information-recording medium according to claims l and 8, characterized by existence of the ratio of the numbers of Te, Ge, and Sb /or Bi atoms in the area, which is surrounded by the composition points of A₄ (Te 46.5 , Ge 4l.5 , Sb /or Bi₁₂), B₄ (Te₅₄ , Ge 6.5 ,Sb /or Bi 39.5 ), C₄ (Te₆₂, Ge₄, Sb /orBi₃₄), and D₄ (Te₅₅, Ge₃₉, Sb /or Bi₆) in a triangle diagram showing the range of composition.
Claim 11
Dependent Claim 55 words
l0. An optical information-recording medium according to claims l and 9, characterized by satisfac­tion of the following formula by the ratio of the numbers of Te, Ge and Sb /or Bi atoms: x·50 GeTe + (l-x)·20 Sb₂Te₃ / or (l-x)·20 Bi₂Te₃ or Te 60-l0x Ge 50x (Sb/or Bi) 40-40x (wherein 0.05 ≦ × ≦ 0.8)
Claim 12
Dependent Claim 131 words
An optical information-recording medium according to claims l and 5, characterized by Te, Ge, Sb /or Bi and Se as main components and existence of the ratio of the numbers of Te, Ge, and Sb /or Bi atoms in the area, which is surrounded by the composition points. of A₁ (Te₃₈, Ge₅₉, Sb /or Bi₃), B₁ (Te₅₀, Ge₂, Sb /or Bi₄₈), C₁ (Te₇₀, Ge₂, Sb /or Bi₂₈), and D₁ , Ge₃₄, Sb /or Bi₃) in a triangle diagram showing the range of composition, and equipment of substrate material with the recording thin film in which the concentration (atomic %) of Se is 0 ≦ m ≦ 30 atomic % in the following formula of the total composition: (Te x , Ge y , Sb /or Bi z ) l00-m Se m
Claim 13
Dependent Claim 76 words
An optical information-recording medium according to claims l and ll, characterized by existence of the ratio of the numbers of Te, Ge, and Sb /or Bi atoms in the area, which is surrounded by the composition points of A₂ (Te₄₂, Ge₅₅, Sb /or Bi₃), B₂ (Te₅₃, Ge₂, Sb /or Bi₄₅), C₂ (Te 64.5 , Ge₂, Sb /or Bi 33.5 ), and D₂ (Te₅₇, Ge₄₀, Sb /or Bi₃) in a triangle diagram showing the range of composition.
Claim 14
Dependent Claim 76 words
An optical information-recording medium according to claims l and l2, characterized by existence of the ratio of the numbers of Te, Ge, and Sb /or Bi atoms in the area, which is surrounded by the composition points of A₃ (Te 44.5 , Ge 52.5 , Sb /or Bi₃), B₃ (Te₅₅, Ge₂, Sb /or Bi₄₃), C₃ (Te₆₃, Ge₂, Sb /or Bi₃₅), and D₃ (Te₅₄, Ge₄₃, Sb /or Bi₃) in a triangle diagram showing the range of composition.
Claim 15
Dependent Claim 79 words
An optical information-recording medium according to claims l and l3, characterized by existence of the ratio of the numbers of Te, Ge, and Sb /or Bi atoms in the area, which is surrounded by the composition points of A₄ (Te 46.5 , Ge 4l.5 , Sb /or Bi₁₂), B₄ (Te₅₄, Ge 6.5 , Sb/or Bi 39.5 ), C₄ (Te₆₂, Ge₄, Sb /or Bi₃₄), and D₄ (Te₅₅, Ge₃₉, Sb /or Bi₆) in a triangle diagram showing the range of composition.
Claim 16
Dependent Claim 69 words
An optical information-recording medium according to claims l and l4, characterized by consti­tution with quaternary elements of Te, Ge, Sb /or Bi and Se and satisfaction of the following formula by the atomic ratios: x·50 Ge(Te,Se) + (l-x)·20 Sb₂(Te,Se)₃ /or (l-x)₂₀·Bi₂(Te,Se)₃ or (Te,Se) 60-l0x Ge 50x (Sb/or Bi) 40-40x (wherein 0.05 ≦ × ≦ 0.8) and also the Se concentration of 30 or less atomic % of total concentration.
Claim 17
Dependent Claim 51 words
An optical information-recording medium according to claims l and l5, characterized by existence of concentration of Se in the range of 5 ≦ m ≦ l5 atomic % in the following formula of the whole composition: (Te x , Ge y , Sb /or Bi z ) 100-m Se m .

References Cited (Backward Citations)

EP0153807A1 Cited
EP0169367A1 Cited

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