Near infrared lens

Abstract

The invention discloses a near infrared lens, which comprises four groups of lenses along an optical axis from an object space to an image space, wherein a first lens is a falcate lens with negative power; the convex surface of the first lens faces to the object space and is a non-spherical surface; a second lens is a falcate lens with positive or negative power; the convex surface of the second lens faces to the image space; a third lens is a lenticular, convexo-plane or falcate lens with positive power; when the third lens is convexo-plane or falcate, the convex surface of the third lens faces to the object space; and a four lens is a lens with positive power and is a non-spherical surface. Due to the adoption of the design, the requirement of image quality is met under the condition of ensuring a large hole diameter and a large field coverage angle, and the technical effect of small distortion is achieved.

Description

technical field [0001] The invention relates to a near-infrared lens, in particular to a large-aperture, wide-angle, and small-distortion near-infrared lens composed of four groups of lenses. Background technique [0002] The optical lenses used in existing digital products generally adopt ordinary optical lenses, which have a small viewing angle and low image quality. This shortcoming can be overcome by using a wide-angle lens, but the biggest problem with an ordinary wide-angle lens is that the image of an object will be distorted after the optical action of the lens. In the past, there was only spherical glass. Or called barrel deformation, that is, the closer the image is to the edge, the more the image will expand and the straight line will bend into an arc). Eliminate this gap. Ordinary wide-angle lenses need 8 to 10 lenses when the lens angle of view is 80 degrees, and more than 10 to 12 lenses when the lens angle of view is above 100 degrees, resulting in too long ...

AI Technical Summary

Problems solved by technology

As the most common lens in optical instruments, in order to achieve athermalization, generally start with the above three methods, but these methods make the lens structure more complicated, resulting in problems such as increased cost and larger lens volume, which are not suitable for portable lenses. requirement is not met

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