EP0468468A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical disk reproducing method and optical disk reproducing apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1991-07-24
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Granted: —
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Expires: 2011-07-24
Abstract
Abstract A reproducing method for the V-shape groove optical disk is disclosed in which three laser beams are irradiated on a disk (1), and the reflected laser beams are focused on three light receiving units (Ua, Ub, Uc) through object lens (8). The laser beams irradiated on two light receiving units (Ub, Uc) are used for reproducing signal. Each of the two light receiving units (Ub, Uc) has a light receiving segment (19a, 20a) which receives a portion of the reflected light beam which is greater than a half of the total reflected light so that a quality of the reproduced signal is improved.
Inventors
- 👤 Michiyoshi Nagashima
- 👤 Fumiaki Ueno
- 👤 Toshinori Kishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 04:19
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0901; G11B7/0903; G11B7/12; G11B7/13; G11B7/131; G11B7/135; G11B7/1372; G11B7/1378; G11B7/24; G11B7/2407; G11B7/24073; G11B7/24076
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
103 words
An optical disk reproducing method for reproducing signals from a disk (1) having grooves (2) of a V-shaped cross-section with recording signal pits (3) formed in the slopes of said V grooves, said optical disk reproducing method comprising the steps of: irradiating a laser beam on said disk (1) through an object lens (8) in a direction approximately parallel to the axis of said object lens (8) and approximately perpendicular to said disk (1); and receiving on a photoelectric segment (19a; 20a; 22; 23; 25; 26) a reflected light passing through more than half of the half-circular portion of said object lens (8).
Claim 2
Dependent Claim
103 words
An optical disk reproducing method for reproducing signals from a disk (1) having grooves (2) of a V-shaped cross-section with recording signal pits (3) formed in the slopes of said V grooves, said optical disk reproducing method comprising the steps of: irradiating a laser beam on said disk (1) through an object lens (8) in a direction approximately parallel to the axis of said object lens (8) and approximately perpendicular to said disk (1); and receiving on a photoelectric segment (19a; 20a; 22; 23; 25; 26) a reflected light passing through more than half of the half-circular portion of said object lens (8).
Claim 3
Dependent Claim
32 words
An optical disk reproducing method as claimed in Claim 1, wherein a portion less than half of the reflected light from said V-shaped groove slope is not irradiated on said photoelectric segment.
Claim 4
Dependent Claim
102 words
An optical disk reproducing method as claimed in Claim 1, wherein said laser beam is radiated from a laser source (4) through a diffraction grating (5) for forming a plurality of spots on said disk and for receiving said reflected light on a plurality of photoelectric segments (19a, 20a; 22, 23; 25, 26), and wherein a distance between said grating (5) and said laser light source (4) is adjusted so that a portion which is greater than a half of the reflected light from the V-shaped groove slope irradiates on each of said photoelectric segment for producing signal representing the pits (3).
Claim 5
Dependent Claim
14 words
An optical disk reproducing device for reproducing signals from a disk (1) having grooves
Claim 6
Dependent Claim
14 words
An optical disk reproducing device for reproducing signals from a disk (1) having grooves
Claim 7
Dependent Claim
108 words
(2) of a V-shaped cross-section with recording signal pits (3) formed in the slopes of said V grooves, said optical disk reproducing device comprising: a plurality of laser beam sources (4, 5) for producing a plurality of laser beams onto said disk (1); object lens means (8) inserted in a path of said laser beams; a plurality of photoelectric segments (19a, 20a; 22, 23; 25, 26) for receiving, respectively, reflected laser beams from said disk (1) and passing through said objective lens means (8), each said photoelectric segment receiving a portion which is greater than a half of the reflected light passing through said object lens means (8).
Claim 8
Dependent Claim
108 words
(2) of a V-shaped cross-section with recording signal pits (3) formed in the slopes of said V grooves, said optical disk reproducing device comprising: a plurality of laser beam sources (4, 5) for producing a plurality of laser beams onto said disk (1); object lens means (8) inserted in a path of said laser beams; a plurality of photoelectric segments (19a, 20a; 22, 23; 25, 26) for receiving, respectively, reflected laser beams from said disk (1) and passing through said objective lens means (8), each said photoelectric segment receiving a portion which is greater than a half of the reflected light passing through said object lens means (8).
Claim 9
Dependent Claim
25 words
An optical disk reproducing device as claimed in Claim 4, wherein each said photoelectric segment is formed by dividing a photoelectric element into two parts.
Claim 10
Dependent Claim
18 words
An optical disk reproducing device as claimed in Claim 4, wherein said two parts are symmetric in size.
Claim 11
Dependent Claim
18 words
An optical disk reproducing device as claimed in Claim 4, wherein said two parts are asymmetric in size.
References Cited (Backward Citations)
No citation records indexed.
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