Optical data storage medium

• US 6,228,457 B1
• Filed: 09/20/1999
• Issued: 05/08/2001
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Furuyametals Co., Ltd., Sony Disc & Digital Solutions Incorporated (Sony Group Corp.)
• Original Assignee: Furuyametals Co., Ltd., Sony Corporation (Sony Group Corp.), Sony Disc Technology Incorporated (Sony Group Corp.)
• Inventors: Iwasaki, Masaaki, Jinushi, Keiichiro, Miyake, Ryohei, Ueno, Takashi, Aratani, Katsuhisa
• Primary Examiner(s): MULVANEY, ELIZABETH EVANS
• Application Number:
  US09/399,108
• Time in Patent Office: 596 Days
• Field of Search: 428/64.1, 428/64.2, 428/64.4, 428/457, 428/913, 430/270.11, 430/495.1, 430/945, 369/283, 369/288
• US Class Current: 428/64.1
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007
• CPC Class Codes: G11B 7/243 comprising inorganic materials only, e.g. ablative layers
• CPC Class Codes: G11B 7/2534 polycarbonates [PC]
• CPC Class Codes: G11B 7/2542 consisting essentially of organic resins
• CPC Class Codes: G11B 7/256 of layers improving adhesion between layers
• CPC Class Codes: G11B 7/258 of reflective layers
• CPC Class Codes: G11B 7/2585 based on aluminium
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10S 430/146 Laser beam
• CPC Class Codes: Y10T 428/21 Circular sheet or circular blank

Abstract

There is disclosed an optical data storage medium in which the weather resistance of the semitransparent reflective film is improved and the adhesive property between the semitransparent reflective film and a substrate is enhanced, and which has a higher reliability. In an optical data storage medium (6), on the side on which a reproduction light (8) is incident, a first information layer (9) is located while on the side opposite to the side on which the reproduction light (8) is incident, a second information layer (10) is located. A semitransparent reflective film (3) of first information layer (9) is AgPdCu alloy thin films containing 0.5 to 3.0 weight % Pd and 0.1 to 3.0 weight % Cu or AgPdTi alloy thin films containing 0.5 to 3.0 weight % Pd and 0.1 to 3.0 weight % Ti. At the wavelength 650 nm, the optimum film thickness of AgPdCu alloy thin film is 5 to 18 nm and the optimum film thickness of AgPdTi alloy thin film is 10 to 25 nm. At the wavelength 450 nm, the optimum film thickness of AgPdCu alloy thin film is 10 to 25 nm, and the optimum film thickness of AgPdTi alloy thin film is 15 to 25 nm.

Claims

1. An optical data storage medium comprising a total of two or more layers in which an information layer having a semitransparent reflective film and an information layer having a reflective film are laminated, said optical date storage medium being capable of performing at least one operation selected from recording of information and reproduction of information by light radiation from the same direction, wherein the semitransparent reflective film comprises a thin film of an AgPdCu alloy containing 0.5 to 3.0 weight % Pd and 0.1 to 3.0 weight % Cu.

2. An optical data storage medium according to claim 1, wherein the thickness of the semitransparent reflective film is 10 to 25 nm.

3. An optical data storage medium according to claim 1, wherein the thickness of the semitransparent reflective film is 5 to 18 nm.

4. An optical data storage medium comprising a total of two or more layers in which an information layer having a semitransparent reflective film and an information layer having a reflective film are laminated, said optical date storage medium being capable of performing at least one operation selected from recording of information and reproduction of information by light radiation from the same direction, wherein the semitransparent reflective film comprises a thin film of an AgPdTi alloy containing 0.5 to 3.0 weight % Pd and 0.1 to 3.0 weight % Ti.

5. An optical data storage medium according to claim 4, wherein the thickness of the semitransparent reflective film is 15 to 25 nm.

6. An optical data storage medium according to claim 4, wherein the thickness of the semitransparent reflective film is 5 to 18 nm.