Patent US3891304A successfully refreshed from Google Patents.
US3891304A
Expired / Lapsed
US
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Pancratic objective
Assignee: Individual
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Filing: 1973-01-12
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Granted: 1975-06-24
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Expires: 1993-01-12
Abstract
Abstract A varifocal objective with a basic rear lens group of fixed focal length and an afocal front lens assembly of variable magnification ratio has a performance value Z > 4, with WHERE 2Y IS THE IMAGE DIAGONAL, FGmax is the maximum overall focal length and fGmin is the minimum focal length, with a varifocal ratio fGmax/fGmin of about 4.7. The positively refracting first component of the four-component afocal lens assembly consists of four singlets, namely a negative meniscus, a planoconvex lens and two positive menisci, all with forwardly facing convex surfaces.
Inventors
- 👤 Trude Muszumanski
- 👤 Gunter Kurz
- 👤 Irngard Wendisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:21
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/145; G02B15/1451; G02B15/145125
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
201 words
A varifocal objective comprising a positively refracting rear lens group of fixed focal length and a front lens assembly of variable mangification ratio, said lens assembly including: a positive first component consisting of four simple lenses; negative second and third components, said second component being movable along the optical axis and having a fixed focal length fII, whereas said third component is movable in dependence on the movement of said second component to achieve a constant image plane; and a positive fourth component adjacent to said rear lens group to direct divergent light rays from said third component in substantially axial direction towards said rear lens group; said components conforming substantially to the parameters of the following table given in order from front to rear with r1 to r25 designating the radii of curvature of the lens surfaces, d1 to d24 designating the axial thicknesses and separations, nd designating the indices of refraction and Nu d designating the Abbe numbers, fGmin, fGM and fGmax being the minimum focal length, the mean focal length and the maximum focal length, respectively, 2y being the length of the diagonal of the image frame and Z being a performance value calculated according to the formula
Claim 2
Dependent Claim
201 words
A varifocal objective comprising a positively refracting rear lens group of fixed focal length and a front lens assembly of variable mangification ratio, said lens assembly including: a positive first component consisting of four simple lenses; negative second and third components, said second component being movable along the optical axis and having a fixed focal length fII, whereas said third component is movable in dependence on the movement of said second component to achieve a constant image plane; and a positive fourth component adjacent to said rear lens group to direct divergent light rays from said third component in substantially axial direction towards said rear lens group; said components conforming substantially to the parameters of the following table given in order from front to rear with r1 to r25 designating the radii of curvature of the lens surfaces, d1 to d24 designating the axial thicknesses and separations, nd designating the indices of refraction and Nu d designating the Abbe numbers, fGmin, fGM and fGmax being the minimum focal length, the mean focal length and the maximum focal length, respectively, 2y being the length of the diagonal of the image frame and Z being a performance value calculated according to the formula
Claim 3
Dependent Claim
146 words
A varifocal objective comprising a positively refracting rear lens group and an afocal front lens assembly of variable magnification ratio, satisfying the relationship fII > fGmin 6y, fGmin being the minimum overall focal length of the objective and 2y being its image diagonal, said afocal lens assembly including: a positive first component consisting of four air-spaced singlets each having a forwardly convex surface, all but the first of said singlets being positively refracting; axially shiftable negative second and third components, fII being the individual focal length of said second component; and an axially fixed positive fourth component; said first, second, third and fourth components and said rear lens group having individual focal lengths fI, fII, fIII, fIV and fV, respectively, of substantially the following numerical values referred to a mean focal length of numerical value unity: fI +2.168 fII -0.600 fIII -2.093 fIV +1.237 fV +1.030.
Claim 4
Dependent Claim
146 words
A varifocal objective comprising a positively refracting rear lens group and an afocal front lens assembly of variable magnification ratio, satisfying the relationship fII > fGmin 6y, fGmin being the minimum overall focal length of the objective and 2y being its image diagonal, said afocal lens assembly including: a positive first component consisting of four air-spaced singlets each having a forwardly convex surface, all but the first of said singlets being positively refracting; axially shiftable negative second and third components, fII being the individual focal length of said second component; and an axially fixed positive fourth component; said first, second, third and fourth components and said rear lens group having individual focal lengths fI, fII, fIII, fIV and fV, respectively, of substantially the following numerical values referred to a mean focal length of numerical value unity: fI +2.168 fII -0.600 fIII -2.093 fIV +1.237 fV +1.030.
Claim 5
Dependent Claim
26 words
A varifocal objective as defined in claim 2 wherein said singlets are, from front to rear, a negative meniscus, a planoconvex lens and two positive menisci.
Claim 6
Dependent Claim
26 words
A varifocal objective as defined in claim 2 wherein said second and third components have limiting axial positions defining a varifocal ratio fGmax/fGmin of substantially 4.7.
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) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |