US4484803A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Objective lens for regenerating a video disc
Assignee: Konica Minolta Inc
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Filing: 1982-11-22
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Granted: 1984-11-27
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Expires: 2002-11-22
Abstract
Abstract This invention relates to an objective lens for regenerating a video disc or the like. A semiconductor laser is used as a light source to directly drive an objective lens for carrying out tracking, and thus the lens must be small and light-weight, but the aberration on the optical axis could well be corrected. However, because of small-size of lens, a manufacture error such as eccentricity is greatly affected. A positive meniscus lens on the image side is approximated to a concentric configuration by an objective lens comprising two lenses whereby the influence resulting from eccentricity may be minimized.
Inventors
- 👤 Norikazu Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:53
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/02; G02B13/00; G02B13/24
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
140 words
An objective lens for regenerating a video disc, or the like, comprising a first lens, which is a cemented positive lens having a positive lens and a negative lens arranged in named order from an object side, and a second lens which is a positive meniscus lens with a concave surface directed towards the object, characterized by satisfying itself with the conditions as follows: 1.1f<r5<1.8f (1) -5.2f<(r2/n2-n1)<-3.5f (2) 0.6f<d1+d4<0.72f (3) where f: resultant focal length of an overall system r2: radius of curvature of a cemented surface of a first lens r5: radius of curvature of a surface on an image side of a second lens d1: thickness of an optical axis of a first lens d4: thickness of an optical axis of a second lens n1: refractive index of the first lens n2: refractive index of the second lens.
Claim 2
Dependent Claim
140 words
An objective lens for regenerating a video disc, or the like, comprising a first lens, which is a cemented positive lens having a positive lens and a negative lens arranged in named order from an object side, and a second lens which is a positive meniscus lens with a concave surface directed towards the object, characterized by satisfying itself with the conditions as follows: 1.1f<r5<1.8f (1) -5.2f<(r2/n2-n1)<-3.5f (2) 0.6f<d1+d4<0.72f (3) where f: resultant focal length of an overall system r2: radius of curvature of a cemented surface of a first lens r5: radius of curvature of a surface on an image side of a second lens d1: thickness of an optical axis of a first lens d4: thickness of an optical axis of a second lens n1: refractive index of the first lens n2: refractive index of the second lens.
Claim 3
Dependent Claim
9 words
An objective lens of claim 1 characterized by n2-n1≧0.2.
Claim 4
Dependent Claim
75 words
An objective lens according to claim 2, as specified by the following data: ______________________________________
f = 1.0 N.A. = 0.5 M = 0
dc = 0.2667 W.D. = 0.5113
r.sub.1 = 1.6710
d.sub.1 = 0.4
n.sub.1 = 1.51032
ν.sub.1 = 64.1
r.sub.2 = -1.1148
d.sub.2 = 0.2222
n.sub.2 = 1.78439
ν.sub.2 = 25.4
r.sub.3 = -2.7925
d.sub.3 = 0.0222
r.sub.4 = 0.7172
d.sub.4 = 0.2889
n.sub.3 = 1.78439
ν.sub.3 = 25.4
r.sub.5 = 1.6805
______________________________________
Claim 5
Dependent Claim
75 words
An objective lens according to claim 2, as specified by the following data: ______________________________________
f = 1.0 N.A. = 0.5 M = 0
dc = 0.2667 W.D. = 0.5183
r.sub.1 = 1.4143
d.sub.1 = 0.3556
n.sub.1 = 1.51032
ν.sub.1 = 64.1
r.sub.2 = -1.3234
d.sub.2 = 0.2222
n.sub.2 = 1.82361
ν.sub.2 = 23.9
r.sub.3 = -3.0798
d.sub.3 = 0.0222
r.sub.4 = 0.6882
d.sub.4 = 0.2444
n.sub.3 = 1.82361
ν.sub.3 = 23.9
r.sub.5 = 1.2774
______________________________________
Claim 6
Dependent Claim
75 words
An objective lens according to claim 2, as specified by the following data: ______________________________________
f = 1.0 N.A. = 0.5 M = 0
dc = 0.2667 W.D. = 0.5098
r.sub.1 = 1.7624
d.sub.1 = 0.4
n.sub.1 = 1.51032
ν.sub.1 = 64.1
r.sub.2 = -1.1309
d.sub.2 = 0.2222
n.sub.2 = 1.82361
ν.sub.2 = 23.9
r.sub.3 = -2.7088
d.sub.3 = 0.0222
r.sub.4 = 0.7433
d.sub.4 = 0.3111
n.sub.3 = 1.82361
ν.sub.3 = 23.9
r.sub.5 = 1.7443
______________________________________
Claim 7
Dependent Claim
75 words
An objective lens according to claim 2, as specified by the following data: ______________________________________
f = 1.0 N.A. = 0.45 M = 0
dc = 0.2667 W.D. = 0.5181
r.sub.1 = 1.4077
d.sub.1 = 0.3333
n.sub.1 = 1.51032
ν.sub.1 = 64.1
r.sub.2 = -1.1425
d.sub.2 = 0.2222
n.sub.2 = 1.73705
ν.sub.2 = 27.5
r.sub.3 = -3.0298
d.sub.3 = 0.0222
r.sub.4 = 0.6703
d.sub.4 = 0.2444
n.sub.3 = 1.73705
ν.sub.3 = 27.5
r.sub.5 = 1.3665
______________________________________
Claim 8
Dependent Claim
75 words
An objective lens according to claim 2, as specified by the following data: ______________________________________
f = 1.0 N.A. = 0.47 M = 0
dc = 0.2665 W.D. = 0.5133
r.sub.1 = 1.7057
d.sub.1 = 0.3886
n.sub.1 = 1.51032
ν.sub.1 = 64.1
r.sub.2 = -1.1243
d.sub.2 = 0.1777
n.sub.2 = 1.79236
ν.sub.2 = 40.9
r.sub.3 = -2.6581
d.sub.3 = 0.0222
r.sub.4 = 0.7066
d.sub.4 = 0.2887
n.sub.3 = 1.79236
ν.sub.3 = 40.9
r.sub.5 = 1.5189
______________________________________
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) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |