Ultra-short-focus projection optical system

Abstract

The invention discloses an ultra-short-focus projection optical system, which is sequentially provided with a DMD chip, a refractive lens assembly and an aspherical reflecting mirror in the projection direction, and is characterized in that the refractive lens assembly comprises a first lens group capable of moving back and forth relative to the DMD chip, a second lens group capable of moving back and forth relative to the DMD chip, a third lens group capable of moving back and forth relative to the DMD chip and a fourth lens group being static relative to the DMD chip which are sequentially arranged along the projection direction, the focal power of the first lens group is positive, the focal power of the second lens group is negative, the focal power of the third lens group is positive, and the focal power of the fourth lens group is positive. The ultra-short-focus projection optical system is small in volume, high in resolution, less than 0.2 in projection ratio, capable of not defocusing at a high temperature, large in projection distance range and capable of performing batch projection.

Description

[0001] 【Technical field】 [0002] The invention relates to projection technology in the photoelectric display industry, in particular to an ultra-short-focus projection optical system. [0003] 【Background technique】 [0004] In recent years, with the development of projection technology, projectors have been widely used in home, education, office and other fields. Among them, ultra-short-focus projection is widely used in home and office fields due to its short-distance projection of large images. [0005] At present, the design of ultra-short-focus projection lens on the market mainly adopts the structure of refractive lens group and reflective lens group. At present, the ultra-short-focus lens with this structure is usually a telecentric lens, which adopts the principle of secondary imaging, but the size of the reflector Large, and the total length of the entire optical system is long, making it difficult to manufacture and mass-produce; and there are a small number of ultra...

AI Technical Summary

Problems solved by technology

[0005] At present, the design of ultra-short-focus projection lens on the market mainly adopts the structure of refractive lens group and reflective lens group. At present, the ultra-short-focus lens with this structure is usually a telecentric lens, which adopts the principle of secondary imaging, but the size of the reflector Large, and the total length of the entire optical system is long, making it difficult to manufacture and mass-produce; and there are a small number of ultra-short-focus lenses that use plastic aspheric surfaces, but due to high temperature and heat during use, there will be virtual focus. There is no ultra-short-focus lens in the world that can overcome the above shortcomings at the same time.

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