US4385303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical recording and reproducing disc
Assignee: Panasonic Holdings Corp
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Filing: 1981-04-15
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Granted: 1983-05-24
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Expires: 2001-04-15
Abstract
Abstract An optical recording and reproducing disc for recording and/or reproducing information by the application of laser beams having a wavelength λ in the range of 0.7 to 1.0 μm, the disc being constituted by a disc-shaped base having at least one spiral guide track thereon with top surfaces parallel to the surface of the base at a height above the base different from the top surfaces of the portions of the base between the spires of the track, which height is in the range of λ/12 to λ/6, the guide track having a width approximately equal to the effective diameter of the laser beams; and a uniform thickness coating of a light recording material on the top surface of the guide track and the portions of the base between the spires of the guide track, the light recording material being a material the transmittance and/or the reflectance of which is varied by irradiation by the laser beams.
Inventors
- 👤 Nobuo Akahira
- 👤 Michiyoshi Nagashima
- 👤 Shunji Harigae
- 👤 Tomio Yoshida
- 👤 Tadaoki Yamashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:26
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/2407; G11B7/24073; G11B7/24079; G11B7/26
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
An optical recording and reproducing disc for recording and/or producing information by the application of laser beams having a wavelength λ in the range of 0.7 to 1.0 μm, said disc comprising: a disc-shaped base, said base having at least one spiral guide track thereon with top surfaces parallel to the surface of the base at a height above the base different from the top surfaces of the portions of the base between the spires of said track, which height is in the range of λ/12 to λ/6, said guide track having a width approximately equal to the effective diameter of the laser beams; and a uniform thickness coating of a light recording material on said top surface of said guide track and said portions of said base between the spires of said guide track, said light recording material being a material the transmittance and/or the reflectance of which is varied by irradiation by the laser beams.
Claim 2
Dependent Claim
157 words
An optical recording and reproducing disc for recording and/or producing information by the application of laser beams having a wavelength λ in the range of 0.7 to 1.0 μm, said disc comprising: a disc-shaped base, said base having at least one spiral guide track thereon with top surfaces parallel to the surface of the base at a height above the base different from the top surfaces of the portions of the base between the spires of said track, which height is in the range of λ/12 to λ/6, said guide track having a width approximately equal to the effective diameter of the laser beams; and a uniform thickness coating of a light recording material on said top surface of said guide track and said portions of said base between the spires of said guide track, said light recording material being a material the transmittance and/or the reflectance of which is varied by irradiation by the laser beams.
Claim 3
Dependent Claim
28 words
A disc as claimed in claim 1 in which said base is transparent, whereby said laser beams can be directed at said light recording material through said base.
Claim 4
Dependent Claim
34 words
A disc as claimed in claim 1, further comprising a transparent protective layer having a thermal conductivity less than that of said light recording material and placed over said coating of light recording material.
Claim 5
Dependent Claim
53 words
A disc as claimed in claim 1 in which said light recording material is coated on said base in a thickness no greater than two times the difference in height between the top surface of said guide track and the surface of the portions of said base between the spires of said track.
Claim 6
Dependent Claim
29 words
A disc as claimed in claim 1 in which the width of said guide track is in the range of ±20% of the effective diameter of said laser beams.
Claim 7
Dependent Claim
19 words
A disc as claimed in claim 1 in which said guide track comprises a convex portion on said base.
Claim 8
Dependent Claim
19 words
A disc as claimed in claim 1 in which said guide track comprises a concave groove on said base.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |