US3598476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens front member adjustable for focusing
Assignee: Rank Organization Ltd
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Filing: 1969-04-16
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Granted: 1971-08-10
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Expires: 1989-04-16
Abstract
Abstract A front member for a zoom lens which is corrected for aberration defects and incorporates members movable for zooming behind said front member, which front member remains stationary during zooming and consists of three portions, namely a divergent front portion, a convergent intermediate portion and a divergent rear portion, of which only the intermediate portion is movable to effect focusing of the complete objective throughout a range of object distances, the equivalent focal lengths of the three portions being selected in relation to the equivalent focal length of the complete front member to permit stabilization of aberrations throughout the range of focusing movement of the intermediate portion.
Inventors
- 👤 Peter Arnold Merigold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:34
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/143
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
150 words
In an optical objective of the zoom type comprising a front member which for a given object position remains stationary during the zooming relative movements, an assembly located behind the front member and incorporating the members of the objective movable for zooming purposes, and a stationary rear member behind such assembly, the improved front member which is divided into three portions, focusing to suit different object positions being effected by axial movement only of the middle portion of the front member, the front and rear portions thereof remaining stationary, each of such front and rear portions being divergent and having equivalent focal length numerically lying between 1.5fA and 7.5fA (where fA is the equivalent focal length of the complete front member when focused for an infinitely distant object), while the movable middle portion of the front member is convergent and has equivalent focal length lying numerically between 0.25fA and 1.0fA.
Claim 2
Dependent Claim
150 words
In an optical objective of the zoom type comprising a front member which for a given object position remains stationary during the zooming relative movements, an assembly located behind the front member and incorporating the members of the objective movable for zooming purposes, and a stationary rear member behind such assembly, the improved front member which is divided into three portions, focusing to suit different object positions being effected by axial movement only of the middle portion of the front member, the front and rear portions thereof remaining stationary, each of such front and rear portions being divergent and having equivalent focal length numerically lying between 1.5fA and 7.5fA (where fA is the equivalent focal length of the complete front member when focused for an infinitely distant object), while the movable middle portion of the front member is convergent and has equivalent focal length lying numerically between 0.25fA and 1.0fA.
Claim 3
Dependent Claim
35 words
An optical objective front member as claimed in claim 1, in which the rear surface of the stationary front portion of the front member is convex to the front with radius of curvature approximately fA.
Claim 4
Dependent Claim
49 words
An optical objective front member as claimed in claim 2, in which the stationary front portion of the front member consists of a doublet component having a convergent element and a divergent element, with a dispersive internal contact between such elements, such internal contact being concave to the front.
Claim 5
Dependent Claim
92 words
An optical objective front member as claimed in claim 1, in which the front member of the objective comprises a Stationary front portion constituted by a divergent doublet component having its rear surface convex to the front, a stationary rear portion constituted by a simple divergent component having its rear surface convex to the front, and a movable middle portion constituted by two simple convergent components, the total axial movement of such middle portion within the focusing range lying between 0.05 and 2.0 times the equivalent focal length of such middle portion.
Claim 6
Dependent Claim
34 words
An optical objective front member as claimed in claim 1, in which the movable middle portion of the front member consists of two convergent components, each having equivalent focal length between 0.75fA and 1.5fA.
Claim 7
Dependent Claim
43 words
An optical objective front member as claimed in claim 1, in which the total axial movement of the movable middle portion of the front member within the focusing range lies between 0.05 and 2.0 times the equivalent focal length of such middle portion.
Claim 8
Dependent Claim
117 words
In an optical objective of the zoom type, a front member which remains stationary during zooming and comprises three portions of which the middle portion alone is movable for focusing, said front member being constructed substantially in accordance with the following table: Radius Thickness or Refractive Index ndAir Separation R1 + 8.9126 D1 0.1019 1.68868 R2 -18.0832 D2 0.068 1.78456 R3 + 3.9783 S1variable R4 + 5.0561 D3 0.2122 1.62077 R5 - 5.0561 S2 0.0017 R6 + 2.1736 D4 0.2122 1.62093 R7 +16.7001 S3 variable R8 +55.1268 D5 0.068 1.62018 R9 + 5.0911 S4 variable Axial Air Separations Variable for Focusing Purposes d S1 S3 Infinity 0.2547 0.0408 250 0.2239 0.0716 100 0.1750 0.1205 40 0.0408 0.2547
Claim 9
Dependent Claim
117 words
In an optical objective of the zoom type, a front member which remains stationary during zooming and comprises three portions of which the middle portion alone is movable for focusing, said front member being constructed substantially in accordance with the following table: Radius Thickness or Refractive Index ndAir Separation R1 + 8.9126 D1 0.1019 1.68868 R2 -18.0832 D2 0.068 1.78456 R3 + 3.9783 S1variable R4 + 5.0561 D3 0.2122 1.62077 R5 - 5.0561 S2 0.0017 R6 + 2.1736 D4 0.2122 1.62093 R7 +16.7001 S3 variable R8 +55.1268 D5 0.068 1.62018 R9 + 5.0911 S4 variable Axial Air Separations Variable for Focusing Purposes d S1 S3 Infinity 0.2547 0.0408 250 0.2239 0.0716 100 0.1750 0.1205 40 0.0408 0.2547
Claim 10
Dependent Claim
124 words
In an optical objective of the zoom type, a front member which remains stationary during zooming and comprises three portions of which the middle portion alone is movable for focusing, said front member being constructed substantially in accordance with the following table: Radius Thickness or Refractive Index nd Air Separation R1 + 10.5067 D1 0.12 1.68869 R2 -21.3040 D2 0.08 1.78457 R3 + 4.6854 S1 variable R4 + 5.9548 D3 0.25 1.62078 R5 - 5.9548 S2 0.002 R6 + 2.5600 D4 0.25 1.62094 R7 + 19.6616 S3 variable R8 + 67.2000 D5 0.08 1.62109 R9 + 6.0200 S4 variable Axial Air Separations Variable for Focusing Purposes d S1 S3 Infinity 0.30 0.048 250 0.2571 0.0909 150 0.2272 0.1208 75 0.148 0.200 48 0.048 0.30
Claim 11
Dependent Claim
124 words
In an optical objective of the zoom type, a front member which remains stationary during zooming and comprises three portions of which the middle portion alone is movable for focusing, said front member being constructed substantially in accordance with the following table: Radius Thickness or Refractive Index nd Air Separation R1 + 10.5067 D1 0.12 1.68869 R2 -21.3040 D2 0.08 1.78457 R3 + 4.6854 S1 variable R4 + 5.9548 D3 0.25 1.62078 R5 - 5.9548 S2 0.002 R6 + 2.5600 D4 0.25 1.62094 R7 + 19.6616 S3 variable R8 + 67.2000 D5 0.08 1.62109 R9 + 6.0200 S4 variable Axial Air Separations Variable for Focusing Purposes d S1 S3 Infinity 0.30 0.048 250 0.2571 0.0909 150 0.2272 0.1208 75 0.148 0.200 48 0.048 0.30
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) | 1974-08-09 | 1975-02-08 | 1975-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-09 | 1979-02-08 | 1979-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-09 | 1983-02-08 | 1983-08-10 | $7700.00 | Window Closed / Lapsed |