Short-focus lens system

Abstract

The invention relates to the technical field of short-focus lenses, and in particular, relates to a short-focus lens system which comprises a shell and a lens group, the lens group is mounted in the shell, and the shell comprises a main mounting lens cone and a lens adjusting mechanism; the lens adjusting mechanism is connected and mounted on the main mounting lens cone and is used for driving one or more groups of lenses in the lens group to move on the central axis of the main mounting lens cone; and the lens group comprises a refraction lens group and an aspheric reflector which are sequentially arranged from the image incident side to the image emergent side along the central axis of the main installation lens cone. The influence of temperature change on lens deformation is considered in design and selection of surface type parameters of the spherical lens, it can be guaranteed that the short-focus lens system has good image distortion prevention performance in a high-temperature environment; in addition, a middle group adjusting part is arranged to drive the lenses in the lens group to move; therefore, the focal length under different projection pictures can be adjusted, and the definition under pictures of different sizes can be ensured.

Description

technical field [0001] The invention relates to the technical field of short-focus lenses, in particular to a short-focus lens system. Background technique [0002] In recent years, with the development of projection technology, projectors have been widely used in various scenarios. Among them, ultra-short-focus projection equipment is widely used in home and office fields due to its short distance projection and large screen characteristics. [0003] In order to achieve a smaller equipment volume in the existing short-focus lens optical system, more aspheric mirrors are usually added to the optical lens group to process the optical path, but the manufacturing cost of the equipment is high due to the difficulty of processing aspheric mirrors. In addition, since the aspheric mirror is more sensitive to errors, the installation accuracy of the aspheric mirror is relatively high, which is also more likely to lead to the problem that the final product has a low manufacturing yie...

AI Technical Summary

Problems solved by technology

[0003] In order to achieve a smaller equipment volume in the existing short-focus lens optical system, more aspheric mirrors are usually added to the optical lens group to process the optical path, but the manufacturing cost of the equipment is high due to the difficulty of processing aspheric mirrors. In addition, because the aspheric mirror is more sensitive to errors, the aspheric mirror has higher requirements for installation accuracy during installation, which is more likely to lead to the problem of low manufacturing yield of the final product and the inability to carry out mass production

There are also a small number of lenses that directly use a large number of plastic aspheric mirrors in order to reduce costs. However, plastic aspherical mirrors will be deformed due to high temperature and heat during product use, which will affect the final presentation of the picture.

At present, there is no ultra-short-focus lens on the market that can overcome the above shortcomings at the same time.

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