Large-aperture low-cost optical imaging system

Abstract

The invention discloses a low-cost optical imaging system with a large aperture, which is sequentially provided with a first lens, a second lens, a diaphragm, a third lens, an aspheric double-glued lens and an optical filter from the object side to the image surface; the aspheric surface The doublet lens comprises a fourth lens and a fifth lens cemented together, the first lens and the fourth lens are all negative focal length lenses, the second lens, the third lens, and the fifth lens are all positive focal length lenses, the first lens, the second lens The second lens, the fourth lens and the fifth lens are all aspherical lenses, the third lens is a spherical lens; the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, and the fourth lens The focal length of the fifth lens is f4, and the focal length of the fifth lens is f5, where f1, f2, f3, f4, and f5 satisfy: f1<‑3, f4<‑60, f5>30,0.05 <f1 f4<5，‑5<f1 f5<5，f2 f3>2. The aperture of the optical imaging system of the present invention reaches more than Fno1.6, and the relative illuminance reaches more than 70%, which can effectively control the aperture and thickness of the lens and reduce the tolerance sensitivity of the system.< / f1>

Description

【Technical field】 [0001] The invention relates to the field of optical imaging systems, in particular to a low-cost optical imaging system with a large aperture. 【Background technique】 [0002] There are some disadvantages in the monitoring fixed-focus lenses currently used in the market: [0003] (1) The aperture is small, mostly Fno 2.0 or Fno 2.2, so the amount of light entering the lens is small, and the shooting illumination is only about 50%; [0004] (2) The distortion is large, and the deformation caused by shooting and imaging is large, which cannot truly reflect the object; [0005] (3) The amount of infrared defocus is large, and the image taken at night is relatively blurred; [0006] (4) The cost is higher. [0007] The present invention is proposed based on solving the above deficiencies. 【Content of invention】 [0008] The technical problem to be solved by the present invention is to provide a low-cost optical imaging system with a large aperture, the op...

AI Technical Summary

Problems solved by technology

[0003] (1) The aperture is small, mostly Fno 2.0 or Fno 2.2, so the amount of light entering the lens is small, and the shooting illumination is only about 50%;

[0004] (2) The distortion is large, and the deformation caused by shooting and imaging is large, which cannot truly reflect the object;

[0005] (3) The amount of infrared defocus is large, and the image taken at night is relatively blurred;

[0006] (4) Higher cost

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