Varifocal optical system having ultra thin type and low cost

Abstract

The invention discloses a varifocal optical system having ultra thin type and low cost, which comprises a light-sensitive chip, a first lens group, a second lens group, a third lens group and a diaphragm, wherein the first lens group is changed relative to the position of the light-sensitive chip in the zooming process; the second lens group is changed relative to the positions of the light-sensitive chip and the first lens group in the zooming process; the third lens group can directly adjust a back focus; and the diaphragm is arranged between the first lens group and the second lens group. The focus of the whole first lens group is negative, the focus of the whole second lens group is positive, and the focus of the whole third lens group is positive. The system has the advantages of small volume, ultra thin type, light weight, medium aperture, popularized technological requirements and the like, and is widely applied in the aspects of cameras and camera mobile phones.

Description

【Technical field】 [0001] The invention relates to a zoom optical system, in particular to a zoom optical system with small volume, ultra-thin type, light weight, medium aperture, popular process requirements, and low-cost zoom magnification below 3.6 times, which is applied to a camera system. 【Background technique】 [0002] At present, the zoom ratio of the zoom lens of mainstream ultra-thin digital cameras and mobile phones is less than 3.6 times. There are mainly three structures: traditional straight-through type, group side-shift type and periscope type. The disadvantages of these three types of structures are as follows: [0003] 1. Traditional straight-through type: the advantage is that the technology is relatively mature, and the disadvantage is that the thickness of the lens group is too large, resulting in a large lens thickness, which is the thickest among the above three structures. [0004] 2. Group side-shift type: the advantage is that the thickness of the le...

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Problems solved by technology

[0003] 1. Traditional straight-through type: the advantage is that the technology is relatively mature, and the disadvantage is that the thickness of the lens group is too large, resulting in a large lens thickness, which is the thickest among the above three structures

[0004] 2. Group side-shift type: the advantage is that the thickness of the lens is thinner than the traditional straight-through type, but when the lens shrinks, a group needs to be moved sideways, and the optical axis of the lens does not coincide with the center of the lens barrel, resulting in a more difficult process Big

[0005] 3. Periscope type: the advantage is that the thickness is relatively thin, and the disadvantage is that the aperture is relatively small, generally around F3.5, and the imaging effect is not as good as the straight-through type

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