TW330245B - Zoom projection lens with very long rear focal length - Google Patents
Zoom projection lens with very long rear focal lengthInfo
- Publication number
- TW330245B TW330245B TW086107861A TW86107861A TW330245B TW 330245 B TW330245 B TW 330245B TW 086107861 A TW086107861 A TW 086107861A TW 86107861 A TW86107861 A TW 86107861A TW 330245 B TW330245 B TW 330245B
- Authority
- TW
- Taiwan
- Prior art keywords
- lens
- sub
- focal length
- object side
- abbe number
- Prior art date
Links
Landscapes
- Lenses (AREA)
Abstract
A zoom projection lens with a very long rear focal length comprises: - A front lens group including a first lens which is a convex lens, a second and a third lenses of negative meniscus which are convex toward the object side, a fourth lens of positive meniscus with the surface of the smaller radius of curvature facing the object side; and - A rear lens group including a fifth lens which is a planoconvex lens with the plane surface facing the object side, a sixth lens which is a biconvex lens, a seventh lens of negative meniscus cemented to the sixth lens with the surface of the larger radius of curvature facing the image side, an eighth lens of negative meniscus with the surface of the larger radius of curvature facing the object side, a ninth lens which is a planoconvex lens with the plane surface facing the object side, and a tenth lens which is a biconvex lens. The front and rear lens groups must satisfy the following conditions: 1.2 <= [|f.sub.A| / f.sub.W] <= 1.5 V.sub.3 x N.sub.3 >= 90 V.sub.6 - V.sub.7 > 30 [|f.sub.A + f.sub.B| / f.sub.B] <= 0.2 where f.sub.A is the focal length of the front lens group, f.sub.B is the focal length of the rear lens group, f.sub.W is the focal length of the entire zoom lens system at its wide-angle end, N.sub.3 is the refractive index of the third lens, V.sub.3 is the Abbe number of the third lens, V.sub.6 is the Abbe number of the sixth lens, and V.sub.7 is the Abbe number of the seventh lens.1
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
TW086107861A TW330245B (en) | 1997-06-06 | 1997-06-06 | Zoom projection lens with very long rear focal length |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
TW086107861A TW330245B (en) | 1997-06-06 | 1997-06-06 | Zoom projection lens with very long rear focal length |
Publications (1)
Publication Number | Publication Date |
---|---|
TW330245B true TW330245B (en) | 1998-04-21 |
Family
ID=58262575
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
TW086107861A TW330245B (en) | 1997-06-06 | 1997-06-06 | Zoom projection lens with very long rear focal length |
Country Status (1)
Country | Link |
---|---|
TW (1) | TW330245B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106154523A (en) * | 2015-04-15 | 2016-11-23 | 佳凌科技股份有限公司 | Zoom lens |
-
1997
- 1997-06-06 TW TW086107861A patent/TW330245B/en not_active IP Right Cessation
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106154523A (en) * | 2015-04-15 | 2016-11-23 | 佳凌科技股份有限公司 | Zoom lens |
CN106154523B (en) * | 2015-04-15 | 2019-04-19 | 佳凌科技股份有限公司 | Zoom lens |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
MM4A | Annulment or lapse of patent due to non-payment of fees |