US4235508A
Expired / Lapsed
US
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Dual focal length objective
Assignee: Questar Corp
•
Filing: 1978-07-17
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Granted: 1980-11-25
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Expires: 1998-07-17
Abstract
Abstract The invention provides a highly corrected, parfocalized, two-focal-length optical system comprising a primary image producing group consisting of a catadioptric lens system which forms its image within a first, positive field lens, and a second group comprising a symmetrical relay system coaxial with the primary group and movable axially relative to the primary image producing group, the relay system reimaging the image formed by the primary group through a second, negative field lens onto the fixed plane of the final image, movement of the relay lens between its extreme positions permitting close focusing of the entire system without altering its overall length.
Inventors
- 👤 Edward K. Kaprelian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:32
CPC Classifications
G; G02; G02B; G02B17/00; G02B17/08; G02B17/0896; G02B17/0804; G02B17/0808; G02B17/0852; G02B17/0884
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
111 words
A parfocalized dual focal length objective comprising a catadioptric primary image former (10) producing a primary image (14), a field lens in the plane of the primary image (L 2 ), a symmetrical, axially movable relay lens system (12) positionable at either of its two conjugate distances for reimaging the primary image at a final focal plane, and a negative field flattener (L 8 ) positioned forward of the final focal plane, said axially movable symmetrical relay system (12) comprising two spaced apart doublets (L 3 , L 4 and L 6 , L 7 ) and a bioconvex crown singlet (L 5 ) between and spaced equidistantly from said doublets.
Claim 2
Dependent Claim
111 words
A parfocalized dual focal length objective comprising a catadioptric primary image former (10) producing a primary image (14), a field lens in the plane of the primary image (L 2 ), a symmetrical, axially movable relay lens system (12) positionable at either of its two conjugate distances for reimaging the primary image at a final focal plane, and a negative field flattener (L 8 ) positioned forward of the final focal plane, said axially movable symmetrical relay system (12) comprising two spaced apart doublets (L 3 , L 4 and L 6 , L 7 ) and a bioconvex crown singlet (L 5 ) between and spaced equidistantly from said doublets.
Claim 3
Dependent Claim
24 words
A parfocalized dual focal length objective according to claim 1, each of said doublets comprising a bioconvex crown element and a meniscus flint element.
Claim 4
Dependent Claim
20 words
A parfocalized dual focal length objective according to claim 2, said flint elements being positioned outermost in the relay system.
Claim 5
Dependent Claim
142 words
A parfocalized dual focal length objective as claimed in claim 1 wherein the elements have the following values: ______________________________________
Thickness &
efl = 1016mm Separation n.sub.d v
______________________________________
R.sub.1 = -191.49 (Aspheric)
t.sub.1 = 14.9
1.5168 64.20
R.sub.2 = -200.00
S.sub.2 = 324.74
R.sub.3 = -783.6
S.sub.2 = 324.74
R.sub.4 = -200.00
S.sub.3 = 296.97
R.sub.4 = +261.7
t.sub.2 = 10.0
1.5168 64.20
R.sub.5 = -261.7
S.sub.4 = 220.27
R.sub.6 = +126
t.sub.3 = 3.0
1.6034 38.02
R.sub.7 = +48.3
t.sub.4 = 6.0
1.4875 70.04
R.sub.8 = -242.3
S.sub.5 = 37.31
R.sub.9 = +235.3
t.sub.5 = 6.0
1.4875 70.04
R.sub.10 = -235.3
S.sub.6 = 37.31
R.sub.11 = +242.3
t.sub.6 = 6.0
1.4875 70.04
R.sub.12 = -48.3
t.sub.7 = 3.0
1.6034 38.02
R.sub.13 = -126
S.sub.7 = 101.75
R.sub.14 = -15.22
t.sub.8 = 5.0
1.5168 64.20
R.sub.15 = ∞
S.sub.8 = 1.0
______________________________________
Claim 6
Dependent Claim
143 words
A parfocalized dual focal length objective as claimed in claim 1 wherein the elements have the following values: ______________________________________
Thickness &
efl = 1016mm Separation n.sub.d v
______________________________________
R.sub.1 = -191.49 (Aspheric)
t.sub.1 = 14.9
1.5168 64.20
R.sub.2 = -200.00
S.sub.2 = 324.5
R.sub.3 = -783.6
S.sub.2 = 324.5
R.sub.2 = -200.00
S.sub.3 = 300.0
R.sub.4 = +200.00
t.sub.2 = 10.0
1.5168 64.20
R.sub.5 = -200
S.sub.4 = 218.6
R.sub.6 = +139.6
t.sub.3 = 3.0
1.6200 36.34
R.sub.7 = +53.7
t.sub.4 = 6.1
1.4875 70.04
R.sub.8 = -202.5
S.sub.5 = 31.6
R.sub.9 = +238.0
t.sub.5 = 6.1
1.4875 70.04
R.sub.10 = -238.0
S.sub.6 = 31.6
R.sub.11 = +202.5
t.sub. 6 = 6.1
1.4875 70.04
R.sub.12 = -53.7
t.sub.7 = 3.0
1.6200 36.34
R.sub.13 = -139.6
S.sub.7 = 104.5
R.sub.14 = -16.33
t.sub.8 = 5.0
1.5168 64.20
R.sub.15 = ∞
S.sub.8 = 1.0
______________________________________
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |