US3840290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens system having four movable members
Assignee: United States Department of the Navy
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Filing: 1973-08-13
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Granted: 1974-10-08
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Expires: 1993-08-13
Abstract
Abstract A zoom lens system having four movable lens groups, the focal length thereof being continuously variable over a range of substantially 6 to 18 inches.
Inventors
- 👤 E Betensky
- 👤 A Schwarz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:13
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/02; G02B7/04; G02B7/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
359 words
A variable focal length zoom lens system having five lens groups successively positioned beginning with the group nearest the object end and ending with the group nearest the image end, comprising: a first lens group including a front singlet negative meniscus lens A, a double convex singlet lens B spaced rearwardly of said lens A at a fixed axial distance S1, and a second singlet positive meniscus lens C spaced rearwardly of said lens B at a fixed axial distance S2; a second lens group movable relative to said first lens group over a variable axial distance S3 including a front singlet negative meniscus lens D, a positive meniscus lens E spaced rearwardly of said lens D at a fixed axial distance S4, and a negative meniscus lens F positioned rearwardly of said lens E and forming a doublet lens therewith; a third lens group movable relative to said second lens group over a variable axial distance S5 including a front double concave lens G and a positive meniscus lens H positioned rearwardly of said lens G and forming a doublet lens therewith; a fourth lens group movable relative to said third lens group over a variable axial distance S6 including a first double convex lens J, a second double convex lens K spaced rearwardly from said lens J at a fixed axial distance S7 and a negative meniscus lens L positioned rearwardly of said lens K and forming a doublet lens therewith; and a fifth lens group including a front double convex lens M, a double concave lens N positioned rearwardly of said lens M and forming a doublet lens therewith, a positive meniscus lens P spaced rearwardly of said lens N at a fixed axial distance S9 and a negative meniscus lens Q spaced rearwardly of said lens P at a fixed axial distance S10, said fourth lens group being movable relative to said fifth lens group over a variable axial distance S8; the values for the thicknesses and the front surface (X)1 and rear surface (X)2 radii of said lenses A to Q and said fixed distances S being substantially as given in the table hereinbelow,
Claim 2
Dependent Claim
359 words
A variable focal length zoom lens system having five lens groups successively positioned beginning with the group nearest the object end and ending with the group nearest the image end, comprising: a first lens group including a front singlet negative meniscus lens A, a double convex singlet lens B spaced rearwardly of said lens A at a fixed axial distance S1, and a second singlet positive meniscus lens C spaced rearwardly of said lens B at a fixed axial distance S2; a second lens group movable relative to said first lens group over a variable axial distance S3 including a front singlet negative meniscus lens D, a positive meniscus lens E spaced rearwardly of said lens D at a fixed axial distance S4, and a negative meniscus lens F positioned rearwardly of said lens E and forming a doublet lens therewith; a third lens group movable relative to said second lens group over a variable axial distance S5 including a front double concave lens G and a positive meniscus lens H positioned rearwardly of said lens G and forming a doublet lens therewith; a fourth lens group movable relative to said third lens group over a variable axial distance S6 including a first double convex lens J, a second double convex lens K spaced rearwardly from said lens J at a fixed axial distance S7 and a negative meniscus lens L positioned rearwardly of said lens K and forming a doublet lens therewith; and a fifth lens group including a front double convex lens M, a double concave lens N positioned rearwardly of said lens M and forming a doublet lens therewith, a positive meniscus lens P spaced rearwardly of said lens N at a fixed axial distance S9 and a negative meniscus lens Q spaced rearwardly of said lens P at a fixed axial distance S10, said fourth lens group being movable relative to said fifth lens group over a variable axial distance S8; the values for the thicknesses and the front surface (X)1 and rear surface (X)2 radii of said lenses A to Q and said fixed distances S being substantially as given in the table hereinbelow,
Claim 3
Dependent Claim
36 words
A variable focal length system as described in claim 1 wherein: the values for the refractive index (N) and Abbe number (V) of said lenses A to Q are substantially as given in the table hereinbelow,
Claim 4
Dependent Claim
32 words
A variable focal length system as described in claim 2 wherein: the values for the lens power (K) of said lenses A to Q are substantially as given in the table hereinbelow,
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |