Near Infrared Interactive Projection Lens

Abstract

The invention provides a near-infrared interactive projection lens. The near-infrared interactive projection lens sequentially comprises a first lens body, a reflective optical surface, a second lens body, a third lens body and a fourth lens body from the imaging side to the image source side, wherein the first lens body has negative focal power, the imaging side of the first lens body is a convex surface, and the image source side of the first lens body is a concave surface; the reflective optical surface enables an optical path to be bent; the second lens body has positive focal power, and the image source side of the second lens body is a convex surface; the third lens body has positive focal power, the imaging side of the third lens body is a convex surface, and the image source side of the third lens body is a concave surface; the fourth lens body has positive focal power. The lens satisfies the relational expression that ImgH / D is larger than 0.25 and smaller than 0.55, wherein ImgH is one half of the length of the diameter diagonal line of an image source; D is the perpendicular height of a part from the imaging side of the first lens body to the central optical axis perpendicular to the image source. By the adoption of the four lens bodies, the near-infrared interactive projection lens has the advantages of being large in field angle and aperture, small in size and the like; meanwhile, glass and plastic are mixed, different types of focal power and different curvature radiuses are distributed reasonably, therefore, the cost of the lens is reduced, influences caused by thermal differences on a system are avoided effectively, and the image-space telecentric characteristic is achieved.

Description

Technical field [0001] The invention relates to an optical projection system composed of four lenses, in particular to a projection lens applicable to a near-infrared interactive system. Background technique [0002] In recent years, with the continuous advancement of technology and the gradual rise of interactive devices, the application range of projection lenses has become wider and wider. In order to be suitable for miniaturized electronic equipment and interactive needs, the projection lens needs to have a sufficient field of view while ensuring miniaturization to obtain a larger picture in a narrower situation, and ensure good imaging quality and information Obtain. The traditional projection lens is generally used for imaging, by using more lenses to eliminate various aberrations to improve the resolution, but the overall length of the projection lens will be longer, which is not conducive to miniaturization; and the general large field of view projection lens , The dist...

AI Technical Summary

Problems solved by technology

Traditional projection lenses are generally used for imaging. By using more lenses to eliminate various aberrations to improve resolution, but the overall length of the projection lens will be longer, which is not conducive to miniaturization; and the general projection lens with a large field of view , the distortion will be larger, and the image quality will be poor.

For example, in the invention patent with the patent number "CN102879888A", the projection lens has seven lenses and a total reflection prism in sequence. The number of lenses and the position of the prism determine that the size of the lens cannot be further reduced. Quality, but this structure cannot guarantee the telecentric characteristics of the lens system, making the light uneven and shadows may appear

Images