Title:
TWO-GROUP ZOOM LENS
Document Type and Number:
Japanese Patent JP3310319
Kind Code:
B2
Abstract:
PURPOSE: To reduce cost and to improve even the performance by using an aspherical plastic lens the two-group zoom lens of six-group and six-element constitution which has an about 38-70mm power variation range.
CONSTITUTION: The zoom lens consists of a 1st positive group I and a 2nd negative group II and varies in power by varying the air interval between both the group. The 1st group consists of a positive meniscus lens L1 which is convex to the object side, a negative lens L2, a positive lens L3, and a positive lens L4 and the 2nd group consists of a positive meniscus lens L5 which is convex to the image side and a negative meniscus lens L6 which is convex to the image side; and L5 is composed of a plastic lens with an aspherical surface, and 0.6<f1/fW<0.9 and 0.6<&verbar f2/fW&verbar <0.9 hold, where f1 and f2 are the focal lengths of the 1st and 2nd groups and fW is the focal length of the whole system at the wide-angle end.
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Inventors:
Koji Ogata
Application Number:
JP3075692A
Publication Date:
August 05, 2002
Filing Date:
February 18, 1992
Export Citation:
Assignee:
Olympus Optical Co., Ltd.
International Classes:
G02B13/18; G02B15/16; (IPC1-7): G02B15/16; G02B13/18
Domestic Patent References:
| JP63311224A | ||||
| JP62138818A | ||||
| JP3116110A | ||||
| JP4124607A | ||||
| JP4161914A | ||||
| JP3267909A | ||||
| JP3146916A |
Attorney, Agent or Firm:
Hiroshi Nirazawa (7 outside)