Multi-reflection type ultra-short-focus projection optical system

Abstract

The invention discloses a multi-reflection type ultra-short-focus projection optical system. The system is sequentially provided with a refraction optical assembly, a plane reflector, a convex aspherical reflector and a projection surface according to a projection optical path; the plane reflector is arranged above the refraction optical assembly and veers the optical path; the convex aspherical reflector is arranged in the reflection optical path of the plane reflector; and the projection surface is arranged in the reflection optical path of the convex aspherical reflector. According to the multi-reflection type ultra-short-focus projection optical system of the invention, a secondary reflection mode realized by the plane reflector and the convex aspherical reflector is adopted, so that adistance between the optical system and the projection surface can be greatly shortened, and a projection ratio can be improved; and the distance between the optical system and the projection surfaceis smaller than 30CM, and projection ratios below 0.18 can be still supported; and the convex even-power aspherical reflector is adopted, and the convex even-power aspherical reflector is easy to machine.

Description

【Technical field】 [0001] The invention relates to an ultra-short-focus projection optical system, more precisely, a multi-reflection ultra-short-focus projection optical system. 【Background technique】 [0002] At present, ultra-short-throw projectors have been widely used in home and office fields, but the current ultra-short-throw projection optical system has the following disadvantages: [0003] 1. Catadioptric hybrid ultra-short-focus projection optical system, the refraction part of the lens and the reflection part are coaxial, resulting in a large volume, the light output end of the optical system is far from the projection wall, the throw ratio is small, and space is wasted. [0004] 2. The projection ratio of the refraction ultra-short-throw projection optical system is greater than 0.4. When projecting images, the distance from the wall is not close enough, resulting in the projection images being easily blocked and poor user experience. [0005] Therefore, the pre...

AI Technical Summary

Problems solved by technology

[0003] 1. Catadioptric hybrid ultra-short-focus projection optical system, the refraction part and reflection part of the lens are coaxial, resulting in a large volume, the light output end of the optical system is far from the projection wall, the throw ratio is small, and space is wasted

[0004] 2. The projection ratio of the refraction ultra-short-focus projection optical system is greater than 0.4. When projecting images, the distance from the wall is not close enough, resulting in the projection images being easily blocked and poor user experience.

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