Optical recording medium and disc cartridge

• US 20020054566A1
• Filed: 10/29/2001
• Published: 05/09/2002
• Est. Priority Date: 06/22/1999
• Status: Active Grant

• Current Assignee: Kazuhiko Fujiie, Naohiro Netsu, Takuya Kaeriyama, Tetsu Watanabe, Yasuaki Maeda, Yoshitaka Aoki
• Original Assignee: Kazuhiko Fujiie, Naohiro Netsu, Takuya Kaeriyama, Tetsu Watanabe, Yasuaki Maeda, Yoshitaka Aoki
• Inventors: Fujiie, Kazuhiko, Aoki, Yoshitaka, Kaeriyama, Takuya, Watanabe, Tetsu, Maeda, Yasuaki, Netsu, Naohiro
• Granted Patent: US 6,747,943 B2
• Time in Patent Office: Days
• US Class Current: 720/718
• CPC Class Codes: B29C 2793/0009 Cutting out
• CPC Class Codes: B29C 69/001 a shaping technique combined with cutting, e.g. in parts or slices combined with rearranging and joining the cut parts for reinforced material B29C70/545; B29C49/4278, B29C51/268 take precedence
• CPC Class Codes: B29L 2017/005 CD''s, DVD''s
• CPC Class Codes: G11B 11/10508 by modulating only the magnetic field at the transducer
• CPC Class Codes: G11B 11/10582 Record carriers characterised by the selection of the material or by the structure or form
• CPC Class Codes: G11B 17/03 in containers or trays G11B17/032, G11B17/035 take precedence
• CPC Class Codes: G11B 23/0035 means incorporated in the disc, e.g. hub, to enable its guiding, loading or driving means for driving the head G11B21/06; guiding the disc for centering or locking G11B17/022; turntables or spindles for driving G11B19/2009
• CPC Class Codes: G11B 23/0307 Positioning or centering features
• CPC Class Codes: G11B 23/0308 Shutters G11B23/0317 takes precedence
• CPC Class Codes: G11B 23/0317 Containers with interchangeable record carriers
• CPC Class Codes: G11B 7/007 Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
• 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 7/24038 Multiple laminated recording layers
• CPC Class Codes: G11B 7/24085 Pits

Abstract

An optical recording medium is provided which has a substrate and a signal recording layer provided on the substrate and in which an information signal is recorded in the form of microscopic pits. A light beam is focused on the signal recording layer and some change of the light beam carried by a return light from the signal recording layer is detected to read the information signal recorded on the signal recording layer. The optical recording medium has a diameter of 65 mm or less and a thickness of 0.4 to 0.7 mm. An information signal recording area extends outwardly from a radial position of 12.5 mm or less from the center of the medium. The ratio in area between the information signal recording area and non-signal recording area is 3.4 or more. The storage capacity of this medium is 2 gigabytes or more. The optical recording medium has formed at the center thereof a center hole around which an annular table-abutment convexing to one side of the medium is formed. A magnetic-clamping hub is installed in the center hole and thus the medium is magnetically clamped to a rotation driving mechanism of an optical recording and/or reproducing apparatus. The compactness and high density of recording of the optical recording medium will contribute greatly to a further compact structure of a recording and/or reproducing apparatus in which the medium is to be used.

Claims

1. An optical read/write recording medium comprising:

a disc having a diameter of 65 mm or less and a thickness between and including 0.4 mm and 0.7 mm, the disc further having a center; and

a recording area for recording an information signal on the disc, the recording area extending outwardly 12.5 mm or less from the center of the disc, a ratio in diametrical length between the recording area and a non-recording area on the disc being 3.4 or more, said recording area having an information signal storage capacity of at least 2 Gigabytes.

2. The optical read/write recording medium according to claim 1, wherein said recording area further comprises tracks having a pitch between and including 0.3 μ

m and 0.55 μ

m for recording an information signal represented as pits in said tracks, said pits having a length between and including 0.1 μ

m/bit and 0.22 μ

m/bit.

3. The optical read/write recording medium according to claim 1, further comprising:

a center hole formed at the center of the disc;

an annular table-abutment formed around the center hole and being convex to one side of the disc; and

a magnetic-clamping hub fixed to the annular table-abutment.

4. The optical read/write recording medium according to claim 3, wherein the annular table-abutment is convex by 0.4 mm to 0.7 mm and has an outside diameter of about 14 mm and inside diameter of about 8 mm.

5. An optical read/write recording medium comprising:

a disc having a diameter between 38 mm and 52 mm and a thickness between and including 0.4 mm to 0.7 mm, said disc having a center; and

a recording area on the disc extending outwardly 12.5 mm or less from the center of the disc, said recording area having an information signal storage capacity of at least 1 Gigabyte.

6. The optical read/write recording medium according to claim 5, wherein the recording area further comprises tracks having a pitch between and including 0.3 μ

m and 0.55 μ

m for recording an information signal represented as pits in the tracks, the pits having a length between and including 0.1 μ

m/bit and 0.22 μ

m/bit.

7. The optical read/write recording medium according to claim 5, further comprising:

a center hole formed at the center of the disc;

an annular table-abutment formed around the center hole and being convex to one side of the disc; and

a magnetic-clamping hub fixed to the annular table-abutment.

8. The optical read/write recording medium according to claim 7,

wherein the table-abutment is formed to a same size as that of a second table-abutment formed for a second optical recording medium comprising:

a disc having a diameter of 65 mm or less and a thickness between and including 0.4 mm and 0.7 mm, the disc having a center; and

a recording area for recording an information signal on the disc, the recording area extending outwardly 12.5 mm or less from the center of the disc, a ratio in diametrical length between the recording area and a non-recording area on the disc being 3.4 or more, said recording area having an information signal storage capacity of at least 2 Gigabytes.

9. A read-only optical recording medium simulated to a read/write recording medium, the read/write recording medium having a disc with a diameter of 65 mm or less and a thickness between and including 0.4 mm and 0.7 mm, a recording area on the disc extending outwardly 12.5 mm or less from a center of the disc, the recording area having a storage capacity of at least 2 Gigabytes and a ratio in diametrical length between the recording area and a non-recording area of the disc being 3.4 or more, the read-only optical recording medium comprising:

a substrate formed to a disc shape having a thickness between and including 0.4 mm and 0.6 mm by injecting a resin into a mold having formed thereon a pit pattern on a recording track in which a smallest pit length and a recording track pitch are about 1.4 times larger than a pit length and a track pitch on the read/write recording medium;

a fist information recording layer formed on the pit pattern on the substrate;

a light-transparent sheet between and including 0.05 mm and 0.1 mm in thickness and having on one side thereof a pit pattern formed by thermally stamping a pit-pattern stamper; and

a second information recording layer formed on the pit-pattern side of the light-transparent sheet, wherein the pit pattern on the substrate and pit pattern on the light-transparent sheet join each other with a transparent resin between them, the transparent resin between the substrate and light-transparent sheet having a length between and including 20 μ

m and 35 μ

m.

10. The read-only optical recording medium according to claim 9, wherein the first information recording layer is translucent for optically reading a recorded information signal from the substrate side.

11. The read-only optical recording medium according to claim 9, further comprising:

a center hole formed at the center of the substrate;

an annular table-abutment formed around the center hole and being convex to one side of the substrate; and

a magnetic-clamping hub fixed to the annular table-abutment.

12. The read-only optical recording medium according to claim 11, wherein the annular table-abutment in convex by 0.4 mm to 0.7 mm and has an outside diameter of about 14 mm and inside diameter of about 8 mm.

14. The read-only optical recording medium according to claim 13, wherein the first information recording layer is translucent for optically reading a recorded information signal from the substrate side.

15. The read-only optical recording medium according to claim 13,

a center hole formed at the center of the substrate;

an annular table-abutment formed around the center hole and being convex to one side of the substrate; and

a magnetic-clamping hub fixed to the annular table-abutment.

16. The read-only optical recording medium according to claim 13, wherein the annular table-abutment is convex by 0.4 mm to 0.7 mm and has an outside diameter of about 14 mm and inside diameter of about 8 mm.

18. The disc cartridge according to claim 17, further comprising:

a shutter member slidably mounted along one lateral side of the cartridge for opening and closing at least the writing access opening and reading access opening formed in the cartridge.

20. The disc cartridge according to claim 19, further comprising:

a shutter member slidably mounted along one lateral side of the cartridge for opening and closing at least the writing access opening and reading access opening formed in the cartridge.

13. A read-only optical recording medium simulated to a read-write recording medium, the read-write recording medium including a disc having a diameter between 38 mm and 52 mm and a thickness between and including 0.4 mm and 0.7 mm, a recording area on the disc extending outwardly 12.5 mm or less from a center of the disc, the recording area having an information signal storage capacity of at least 1 GB, the read-only optical recording medium comprising:

a substrate formed to a disc shape having a thickness between and including 0.4 mm and 0.6 mm by injecting a resin in a mold having formed thereon a pit pattern on a recording track in which a smallest pit length and a recording track pitch are about 1.4 times larger than a pit length and a track length on the read-write recording medium;

a fist information recording layer formed on the pit pattern on the substrate;

a light-transparent sheet between and including 0.05 mm and 0.1 mm in thickness and having on one side thereof a pit pattern formed by thermally stamping a pit-pattern stamper; and

a second information recording layer formed on the pit-pattern side of the light-transparent sheet, wherein the pit pattern on the substrate and pit pattern on the light-transparent sheet join each other with a transparent resin between them, the transparent resin between the substrate and light-transparent sheet having a length between and including 20 μ

m and 35 μ

m.

17. A disc cartridge in which a read-write recording medium is encased, the read-write recording medium including a disc having a diameter of 65 mm or less and a thickness between and including 0.4 mm and 0.7 mm, a recording area on the disc extending outwardly 12.5 mm or less from a center of the disc, the recording area having a storage capacity of at least 2 Gigabytes, a ratio in diametrical length between the recording area and a non-recording area of the disc being 3.4 or more, the disc cartridge comprising:

a cartridge having a rectangular shape and including a first side having length between and including 52 mm and 70 mm, and a second side, perpendicular to the first side, having a length between and including 52 mm and 75 mm, the cartridge having a thickness between and including 3 mm and 6 mm; and

at least one opening formed in a side of the cartridge parallel to the read/write recording medium, the opening being a writing and reading access opening through which a radially extending portion of the recording medium is exposed to a light beam from an optical pickup and through which the magnetic-clamping hub is exposed, the opening further being formed deviated to one lateral side from a middle point of a front side of the cartridge.

19. A disc cartridge having a read-write recording medium is encased therein, the read-write recording medium including a disc having a diameter between 38 mm and 52 mm and a thickness between and including 0.4 mm and 0.7 mm, a recording area on the disc extending outwardly 12.5 mm or less from a center of the disc, the recording area having a storage capacity of at least 1 Gigabyte, the disc cartridge comprising:

a cartridge having a rectangular shape and including a first side having a length between and including 41 mm and 57 mm and a second side, perpendicular to the first side, having a length between and including 41 mm and 62 mm, the cartridge having a thickness between and including 3 mm and 6 mm; and

at least an opening formed in a side of the cartridge parallel to the read-write recording medium, the opening being a writing and/or reading access opening through which a radially extending portion of the recording medium is exposed to a light beam from an optical pickup and through which the magnetic-clamping hub is exposed, the opening further being formed deviated to one lateral side from a middle point of a front side of the cartridge.

21. A disc cartridge having a read-only optical recording medium encased therein, the read-only optical recording medium including a disc having a diameter of 65 mm or less and a thickness between and including 0.4 mm and 0.7 mm, a recording area on the disc extending outwardly 12.5 mm or less from a center of the disc, the recording area having a storage capacity of at least 2 Gigabytes, a ratio in diametrical length between the recording area and a non-recording area of the disc being 3.4 or more, the disc cartridge comprising:

a cartridge of a rectangular shape including a first side having a length between and including 52 mm and 70 mm and a second side, perpendicular to the first side, having a length between and including 52 mm and 75 mm, the cartridge having a thickness between and including 3 mm and 6 mm; and

at least one opening formed in a side of the cartridge parallel to the read-only recording medium, the opening being a writing and reading access opening through which a radially extending portion of the recording medium is exposed to a light beam from an optical pickup through which the magnetic-clamping hub is exposed, the opening further being formed deviated to one lateral side from a middle point of a front side the cartridge.

22. The disc cartridge according to claim 21, farther comprising:

a shutter member slidably mounted along one lateral side of the cartridge for opening and closing at least the writing access opening and reading access opening formed in the cartridge.

24. The disc cartridge according to claim 23, further comprising:

a shutter member slidably mounted along one lateral side of the cartridge for opening and closing at least the writing access opening and reading access opening formed in the cartridge.

23. A disc cartridge having a read-only optical recording medium encased therein, the read-only optical recording medium including a disc having a diameter of between 38 mm and 52 mm and a thickness between and including 0.4 μ

m and 0.7 mm, a recording area on the disc extending outwardly 12.5 mm or less from a center of the read-only optical recording medium, the recording area having a storage capacity of at least 1 Gigabyte of an information signal as a pit pattern, the disc cartridge comprising;

a cartridge of a rectangular shape including a first side having a length between and including 41 mm and 52 mm and a second side, perpendicular to the first side, having a second length between and including 41 mm and 62 mm, the cartridge having a thickness between and including 3 mm and 6 mm; and

at least an opening formed in a side parallel to the read-write recording medium, the opening being a writing and/or reading access opening through which a radially extending portion of the optical disc is exposed to a light beam from an optical pickup and through which the magnetic-clamping hub is exposed, the opening being formed deviated to one lateral side from a middle point of a front side of the cartridge.