Title:
【発明の名称】小型のズームレンズ
Document Type and Number:
Japanese Patent JP3352214
Kind Code:
B2
Abstract:
PURPOSE:To obtain the small-sized zoom lens which is shortened in overall lens length while having a power variation ratio of about 2 and a wide field angle, and also has high optical performance over the entire power variation range by composing the zoom lens of two groups and specifying the lens constitution of the respective lens groups. CONSTITUTION:The zoom lens has the 1st group L1 with positive refracting power and the 2nd group L2 with negative refracting power in order from the object side and the interval between both the lens groups L1 and L2 is varied to vary the power. For the purpose, the 1st group L1 has four lenses which are a positive lens 11, a negative lens 12, a positive lens 13, and a positive lens 14, and the 2nd group L2 has two lenses which are a positive lens 21 and a negative lens 22. Then the conditions shown by the expressions are satisfied, where f1 is the focal length of the 1st group L1, fw the focal length of the whole system at the wide-angle end, DL11 the air gap between the lenses 11 and 12, DL21 the air gap between the lenses 21 and 22, and N, 2i the refractive indexes of the materials of the lenses 2i.
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Inventors:
Koji Hoshi
Application Number:
JP4778194A
Publication Date:
December 03, 2002
Filing Date:
February 21, 1994
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B15/16; (IPC1-7): G02B15/16
Domestic Patent References:
| JP5249375A | ||||
| JP5232382A | ||||
| JP2120714A | ||||
| JP7146440A | ||||
| JP273322A | ||||
| JP1193807A | ||||
| JP63311224A | ||||
| JP62251710A | ||||
| JP62138818A | ||||
| JP56128911A | ||||
| JP57201213A | ||||
| JP6256917A | ||||
| JP62284319A |
Attorney, Agent or Firm:
Yukio Takanashi