Patent US4911968A successfully refreshed from Google Patents.
US4911968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical disc
Assignee: Maxell Ltd
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Filing: 1987-11-18
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Granted: 1990-03-27
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Expires: 2007-11-18
Abstract
Abstract An optical recording disc which includes a pair of recording disc substrates opposed to each other with a space therebetween, with a hub situated at the central portion of the disc substrates so that there is formed the closed space between the disc substrates, thereby providing a dual sided recordable optical recording disc. The hub may be formed by a pair of hub halves. There is disposed an annular inner spacer and annular outer spacer around the hub so as to separate the pair of recording disc substrates.
Inventors
- 👤 Tosio Higasihara
- 👤 Ken Yoshizawa
- 👤 Masahiro Suzuki
- 👤 Akira Gotoh
- 👤 Yoshitane Tuburaya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:45
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/24015; G11B7/24097; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
414 words
A dual optical recording disc comprising a first optical disc including a first transparent substrate having a first rotation central hole defined at the center of said first transparent substrate, a first hub half having a hole with a rotation center and a first projected portion juxtapositioned to a first inner surface of said first transparent substrate with a first cylindrical portion of said first hub half projecting through said first rotation central hole juxtapositioned to a second surface of said first transparent substrate circumscribing said first rotation central hole, said rotation center of said hole of said first hub half accurately coinciding with said first rotation central hole of said first transparent substrate, a second optical disc including a second transparent substrate having a second rotation central hole defined at the center of said second transparent substrate, a second hub half having a hole with a rotation center and a second projected portion joined to a first inner surface of said second transparent substrate with a second cylindrical portion of said second hub half projecting through said second rotation central hole juxtapositioned to a second surface of said second transparent substrate circumscribing said second rotation central hole, said rotation center of said hole of the second hub accurately coinciding with said second rotation central hole of said second transparent substrate, wherein the outer surface of the projected portion of the first hub half is bonded with the outer surface of the projected portion of said second hub half, a ring like inner spacer having an inner cylindrical surface engaged with the outer peripheral sides of said first projected portion of said first hub half and said second projected portion of the second hub half, said inner cylindrical surface of said inner spacer being bonded to said respective projected portions of said first hub half and said second hub half, said inner spacer having first and second end surfaces bonded to said first surface of said first transparent substrate and said first surface of said second transparent substrate, and a recording layer for recording tracking signals formed on at least one of the first surfaces of said first transparent substrate and second transparent substrate, a central axis of tracking coinciding with a central axis of said first rotation central hole of said first hub half of said first substrate and a central axis of said second rotation central hole of said second hub half of said second substrate with a high degree of accuracy.
Claim 2
Dependent Claim
414 words
A dual optical recording disc comprising a first optical disc including a first transparent substrate having a first rotation central hole defined at the center of said first transparent substrate, a first hub half having a hole with a rotation center and a first projected portion juxtapositioned to a first inner surface of said first transparent substrate with a first cylindrical portion of said first hub half projecting through said first rotation central hole juxtapositioned to a second surface of said first transparent substrate circumscribing said first rotation central hole, said rotation center of said hole of said first hub half accurately coinciding with said first rotation central hole of said first transparent substrate, a second optical disc including a second transparent substrate having a second rotation central hole defined at the center of said second transparent substrate, a second hub half having a hole with a rotation center and a second projected portion joined to a first inner surface of said second transparent substrate with a second cylindrical portion of said second hub half projecting through said second rotation central hole juxtapositioned to a second surface of said second transparent substrate circumscribing said second rotation central hole, said rotation center of said hole of the second hub accurately coinciding with said second rotation central hole of said second transparent substrate, wherein the outer surface of the projected portion of the first hub half is bonded with the outer surface of the projected portion of said second hub half, a ring like inner spacer having an inner cylindrical surface engaged with the outer peripheral sides of said first projected portion of said first hub half and said second projected portion of the second hub half, said inner cylindrical surface of said inner spacer being bonded to said respective projected portions of said first hub half and said second hub half, said inner spacer having first and second end surfaces bonded to said first surface of said first transparent substrate and said first surface of said second transparent substrate, and a recording layer for recording tracking signals formed on at least one of the first surfaces of said first transparent substrate and second transparent substrate, a central axis of tracking coinciding with a central axis of said first rotation central hole of said first hub half of said first substrate and a central axis of said second rotation central hole of said second hub half of said second substrate with a high degree of accuracy.
Claim 3
Dependent Claim
101 words
The dual optical disc of claim 1, wherein a first recording layer and a second recording layer are formed on the first surface of the first transparent substrate and first surface of the second transparent substrate with the central axis of tracking of the first recording layer, the central axis of tracking of the second recording layer, the central axis of said first rotation central hole of said first hub half of said first substrate and the central axis of said second rotation central hole of said second hub half of said second substrate coinciding with a high degree of accuracy.
Claim 4
Dependent Claim
68 words
The dual optical disc of claim 2, wherein the diameter of the respective holes of the first hub of the first substrate and the second hub of the second substrate is such that a central pin of a stamper for forming a replica layer is tightly engaged in the hole with the central axis of the hole being coaxial with the center of the track of the stamper.
Claim 5
Dependent Claim
44 words
The dual optical disc of claim 2, wherein the respective holes of the first hub and second hub are coaxial with the tracking axis of the first track of the first substrate and the tracking axis of the second track of the second substrate.
Claim 6
Dependent Claim
47 words
The dual optical disc of claim 2, wherein the hole of the first hub of the first substrate and the hole of the second hub of the second substrate are connected and the cylindrical walls of the first and second hubs defining the holes are smoothly connected.
Claim 7
Dependent Claim
50 words
The dual optical disc of claim 2, wherein the projected portion of the first hub in the first surface of the first transparent substrate and the projected portion of the second hub in the first surface of the second transparent substrate form flanges of the respective first and second hubs.
Claim 8
Dependent Claim
293 words
The dual optical recording disc of claim 1, wherein each of said first and second hub halves has a cylindrical member and said first and second projected portions are flanges projecting outward from said cylindrical members, said first and second transparent substrates being provided with a recording layer on at least one surface including recording tracks around a rotation center, each transparent substrate having a central opening at the central portion through which said cylindrical member of said respective hub half is inserted, one surface of each transparent substrate being bonded to a corresponding surface of said flange of the respective hub half around said corresponding central opening so that rotation centers of said recording tracks on said respective recording layer coincide with the center of the respective hub half and said at least one recording layer of one of said transparent substrates is opposed to the surface of the other transparent substrate, said annular inner spacer having a round opening of a diameter for fitting the flange of each hub half, each hub half being accommodated in the round opening of the annular spacer in such a manner that the respective flanges of the hub halves oppose each other with the centers of said hub halves coinciding and the outer cylindrical surfaces of the flanges bonded air tightly with the inner cylindrical surface of the inner spacer defining the round opening, and an annular outer spacer having an inner diameter smaller than the outer diameter of the disc substrate and bonded in an air tight manner between the opposing surfaces of the pair of transparent substrates, whereby the pair of transparent substrates and the outer spacer and inner spacer form a closed space with the recording layer positioned with said closed space.
Claim 9
Dependent Claim
83 words
The dual optical disc of claim 7, wherein one of the hub halves of one of the disc substrates further comprises a flange portion arranged at the end of the cylindrical portion of the one hub half, the other of the hub halves of the other of the disc substrates further comprises a flange portion arranged at the end of the cylindrical portion of the other hub half, and the one hub half is connected to the other hub half as one body.
Claim 10
Dependent Claim
40 words
The optical disc as defined in claim 8 wherein the pair of hub halves comprise a cylindrical body and a flange body in an annular shape respectively, and the flange body is connected on the cylindrical body as one body.
Claim 11
Dependent Claim
22 words
The optical disc as defined in claim 9, wherein the flange body is connected on the cylindrical body with a bonding material.
Claim 12
Dependent Claim
47 words
The optical disc as defined in claim 8, wherein the flange portions of the pair of hub halves are constructed as one body between the pair of substrates so that the flange portion of the one hub half faces the flange portion of the other hub half.
Claim 13
Dependent Claim
33 words
The optical disc as defined in claim 8, wherein a bonding recess is formed on at least one end surface of the flange portions of the pair of hub halves, facing each other.
Claim 14
Dependent Claim
46 words
The optical disc as defined in claim 8, wherein the pair of disc substrates are made of glass, and the hub halves are made of an alloy of iron, nickel and chromium, containing nickel at 42 percent by weight and chromium at 6 percent by weight.
Claim 15
Dependent Claim
44 words
The dual optical recording disc of claim 13, wherein said inner spacer is made of an alloy of iron, nickel and chromium, containing nickel at 42 percent by weight and chromium at 6 percent by weight and the outer spacer is made of aluminum.
Claim 16
Dependent Claim
31 words
The optical disc as defined in claim 8, wherein said hub halves are made of material having a thermal expansion coefficient similar to that of the material of the disc substrate.
Claim 17
Dependent Claim
17 words
The optical recording disc as defined in claim 8, wherein the bonding material is ultraviolet hardening material.
Claim 18
Dependent Claim
149 words
The dual optical recording disc of claim 1, wherein a closed space is formed by the pair of transparent substrates assembled on the bonded hub comprising a cylindrical member inserted in the rotation central hole defined in the central portion of the respective transparent substrates and a flange projected from the cylindrical member in the outward direction so that the transparent substrates are opposed to each other with at least one recording layer formed on one of the opposing surfaces of the transparent disc substrates and an outer spacer disposed between said opposing pair of transparent substrates, characterized in that said flanges are disposed between said transparent substrates and an inner spacer is fitted around the outer cylindrical surface of said flanges and the flanges of the hubs, the inner spacer and the pair of first and second transparent substrates are bonded together by at least one bonding layer.
Claim 19
Dependent Claim
284 words
The dual optical recording disc of claim 1, wherein each of said hub halves has a cylindrical body in which a spindle insertion hole is defined with the center of the spindle hole coinciding with the center of the cylindrical body and a flange having a diameter larger than the diameter of the cylindrical body so that the flange is projected from the cylindrical surface of the cylindrical body and the rotation central hole of each of the first and second transparent substrates coincides with the tracking center of the recording surface formed on the one side of at least one of the transparent substrates, the cylindrical body of the hub half being fitted in the respective rotation central holes of the transparent substrates with the flange of the hub half situated on the surface opposite to the recording surface of the transparent substrate, each of transparent substrates and hub halves being bonded together by bonding material at portions where the disc substrate and the cylindrical surface of the hub half and the disc substrate and the flange are opposed so that a set of disc assembly is formed, the disc assembly being further assembled together in such a manner that the recording layers of the transparent substrates oppose each other with the cylindrical body of the hub half fitted in an annular inner spacer and bonded together by bonding material at portions where the transparent substrates and the inner spacer are opposed, and an outer spacer being fitted between the transparent substrates on the outer peripheral edge portion of the transparent substrates, whereby a closed space surrounded by the outer spacer, inner spacer and the recording surfaces of the transparent substrates is formed.
Claim 20
Dependent Claim
18 words
The dual optical recording disc of claim 18, wherein the bonding material is an ultraviolet light hardening material.
Claim 21
Dependent Claim
48 words
The dual optical disc of claim 1, wherein the recording layer is formed on each of said first substrate and second substrate in such a manner that the rotation center of the hole of the hub is used as the tracking center of pregrooves of said recording layers.
Claim 22
Dependent Claim
45 words
The dual optical recording disc of claim 1, wherein the transparent recording disc substrates are made of glass and the hub is made of an alloy of iron, nickel and chromium, containing nickel at 42 percent by weight and chromium at 6 percent by weight.
Claim 23
Dependent Claim
31 words
The dual optical disc of claim 1, wherein said hub is made of material having a thermal expansion coefficient similar to that of the material of the transparent recording disc substrate.
References Cited (Backward Citations)
JPS56139940A
Cited
US4555716A
Cited
JPS6130653A
Cited
JPS6130654A
Cited
JPS6148143A
Cited
US4686543A
Cited
US4710913A
Cited
EP0498131A1
Cited
EP1092452A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-26 | 1993-09-25 | 1994-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-26 | 1997-09-25 | 1998-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-26 | 2001-09-25 | 2002-03-27 | $7700.00 | Window Closed / Lapsed |