Projection lens and projection equipment

Abstract

The invention provides a projection lens and projection equipment. The projection lens comprises a lens front group and a lens rear group distributed sequentially from an image space to an object space; the front lens group at least comprises five lenses, and the front lens group has negative focal power; and the lens rear group at least comprises four lenses, and the lens rear group has positive focal power. According to the projection lens and projection equipment of the invention, high-precision projection can be realized by using fewer lenses under the condition that the use of a reflection bowl is avoided.

Description

technical field [0001] The present disclosure relates to the technical field of projection display, in particular to a projection lens and projection equipment. Background technique [0002] With the development of micro-projector technology, ultra-short-throw projectors have gradually entered people's field of vision. At present, micro projectors are mainly used in home entertainment, education and learning, business meetings, military and other fields. In the field of projectors, the throw ratio is a key parameter. The lower the throw ratio, the shorter the distance between the projector and the wall, and the smaller the space occupied, but at the same time, the larger the field of view, the more difficult the design. [0003] At present, the throw ratio of projectors is gradually decreasing. There are two mainstream designs, one with a reflective bowl and one without a reflective bowl. The disadvantages of the two options are described below. [0004] With reflective b...

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Problems solved by technology

[0004]With reflective bowl: The reflective surface of the reflective bowl is generally aspherical or free-form surface, which is used to undertake more aberration correction functions, but because the reflective bowl contains many Large optical power, so its tolerances are very sensitive, resulting in a structure with a reflective bowl, which is difficult and time-consuming to assemble

[0005] No reflective bowl: Since this structure does not use a reflective bowl, it generally requires more lenses to correct aberrations. Currently, it meets distortion, CRA (chief ray angle), Projection lenses that require clarity and other requirements generally use more than 11 lenses. Although more lenses can ensure the optical performance of the lens, it will bring more assembly tolerances and increase the difficulty of assembly.

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