Large-view-field small-size ultra-short-focus projection lens

Abstract

The invention discloses a large-view-field small-size ultra-short-focus projection lens, which comprises a refractor group and a reflector group. The refractor group comprises a first lens group at least comprising an aspherical lens and at least one balsaming lens, a second lens group comprising a low-focal-power aspherical lens and other spherical lenses, and a refraction lens closest to the reflector group is an aspherical lens in a third lens group; the reflector group comprises an aspheric reflector. The lens has the advantages of large projection breadth, good manufacturability, low cost and no virtual focus at high temperature.

Description

technical field [0001] The invention relates to the technical field of projection lenses, in particular to an ultra-short-focus projection lens with a large field of view and a small volume. Background technique [0002] In recent years, with the rise of business, entertainment, and home theaters, ultra-short-throw projection lenses are favored by the market because of their short projection distance, small space, large projection format, and good viewing effects. [0003] At present, there are two common ways to achieve short-distance and large-format projection effects: one is to use traditional refracting lenses, generally reverse-telephoto wide-angle lenses, which have a large number of lenses, high cost, large distortion, and the format size is still relatively limited. . The other is a catadioptric lens composed of a refracting lens and a reflector. This catadioptric lens is easy to achieve a large format. The disadvantage is that it contains more aspherical lenses, g...

AI Technical Summary

Problems solved by technology

The wide-angle lens includes a refraction system and a reflection system, and wherein the refraction system includes a first lens group comprising a plurality of spherical lenses and at least one aspheric lens and a second lens group comprising at least two aspheric lenses and at least one spherical lens, the at least two The at least one spherical lens is arranged between any two of the two aspherical lenses, and its effective focal length (Effective Focal Length, EFFL)=-2.89mm, focal number (f / #)=1.67, offset (offset)= 122%, the resolution can reach 67lp / mm, the screen size that can be projected is 40-60 inches, the projection distance is 282-418mm, and the projection ratio is 0.274-0.278. The projection ratio is too large to be realized at a shorter projection distance. Larger projection format

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