2.8 mm small wide-angle lens with high light flux

Abstract

The invention discloses a 2.8 mm small wide-angle lens with high light flux. The 2.8 mm small wide-angle lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens sequentially from object space to image space, wherein the first lens is a convex-concave lens with negative focal power; the second lens is a biconcave lens with negative focal power; the third lens is a biconvex lens with positive focal power; the fourth lens is a concave-convex lens with negative focal power; the fifth lens is a biconvex lens with positive focal power; the sixth lens is a biconcave lens with positive focal power; the seventh lens is a biconvex lens with positive focal power. Compared with the prior art, the 2.8 mm small wide-angle lens has the clear aperture as large as F1.4, has high light flux and is small in size, the total length is 22.2 mm, the optical distortion is about 20%, the lens can realize 3-mega pixels under visible light and infrared conditions without refocusing by cooperating with a chip which is 1 / 2.7 inch in size, suppositional focus is avoided at the temperature ranging from subzero 30 DEG C to 80 DEG C, and the lens has a temperature compensation function.

Description

technical field [0001] The invention relates to the field of lens technology, in particular to a 2.8mm Datong light small wide-angle lens. Background technique [0002] With the development of the security industry, the performance of surveillance cameras is becoming more and more high-end, the size of the chip is increasing, and the number of pixels is also increasing. Pixels larger than 3 million are becoming the mainstream. With the perfect cooperation with the chip, an ideal monitoring picture can be obtained. While ensuring the pixels, ultra-wide-angle lenses are becoming more and more popular. They have a wide monitoring range and a wide field of view. For example, a lens with a focal length of 2.8mm is generally a wide-angle lens and is one of the mainstream surveillance lenses on the market today. The current 2.8mm fixed-focus lens also has the following problems: first, the F-number is not large enough, such as the patent CN 105204140 A, CN 203311085U F-number is 1...

AI Technical Summary

Problems solved by technology

While ensuring the pixels, ultra-wide-angle lenses are becoming more and more popular. They have a wide monitoring range and a wide field of view. For example, a lens with a focal length of 2.8mm is generally a wide-angle lens and is one of the mainstream surveillance lenses on the market today. The current 2.8mm fixed-focus lens also has the following problems: first, the F-number is not large enough, such as the patent CN 105204140 A, CN 203311085U F-number is 1.8, the light flux is not sufficient, and the chip cannot obtain sufficient exposure; secondly, the total length of the lens is relatively long. Long, about 30mm; again, the distortion is relatively large, and the image quality is not ideal in a large field of view, such as the patent CN 105467561 A, the optical distortion is close to 50%

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