Zoom optical system with high resolution, large image plane, low cost, no stray light

Abstract

The present invention relates to a zoom optical system with high resolution, large image plane, low cost and no stray light. From the object side to the image side, a first lens group having a positive focal length, a second lens group having a negative focal length, an iris diaphragm, a third lens group having a positive focal length, a fourth lens group having a positive focal length and a photosensitive chip are disposed in this order. The first lens group, the iris diaphragm and the third lens group are fixed relative to the photosensitive chip, and the second lens group and the fourth lens group can move back and forth relative to the photosensitive chip. In the process of changing the optical system from the short focal length to the long focal length, the second lens group moves towards the third lens group gradually, and the fourth lens group is moved relative to the photosensitive chip to realize the focusing effect. Both the front end and the rear end lens of the third lens group and the lens at the rear end of the fourth lens group are aspherical lenses. In the scheme, the aspherical lenses can correct aberration and field curvature, so that the zoom optical system obtains higher imaging quality.

Description

technical field [0001] The invention relates to the technical field of optical lenses, in particular to a zoom optical system with high resolution, large image surface, low cost and no stray light. Background technique [0002] At present, zoom lenses are widely used in people's daily life. The current market is developing in the direction of high resolution and high image quality. In order to obtain better imaging quality, using chips with larger pixels and more pixels is the solution to the problem. One of the fundamental ways, but the current security monitoring and road condition monitoring devices have the following shortcomings: [0003] Ordinary zoom lenses are often not compatible with large image area and volume. The increase of image area will cause a sharp change in lens volume. Currently, large-screen surveillance lenses on the market, such as lenses with a size of about 1″, have an image area of ​​16.0 mm, its volume is relatively large, and most of them are fi...

AI Technical Summary

Problems solved by technology

[0003] Ordinary zoom lenses are often not compatible with large image area and volume. The increase of image area will cause a sharp change in lens volume. Currently, large-screen surveillance lenses on the market, such as lenses with a size of about 1″, have an image area of ​​16.0 mm, its volume is relatively large, and most of them are fixed-focus lenses, which are difficult to control when the monitoring distance changes;

[0004] At present, the mainstream high-quality surveillance cameras on the market have a low resolution, mostly 1080p, with 2 million pixels. However, with the improvement of data transmission speed, higher-quality image transmission becomes possible. It cannot meet the demand; the current mainstream 1080P lens image plane is mainly 1 / 2.8″, using a 1 / 2.8″ CMOS chip with an effective imaging plane diagonal of 6.2mm, its pixel size is only 2.8μm, and the resolution Not very high; and because the pixels are small, its photosensitivity and color reproduction are not very ideal, and performance improvement is urgently needed;

[0005] Most of the surveillance lenses currently on the market are non-infrared confocal lenses. Therefore, in occasions with many optical wavelength bands, such as in the evening, or when there is some lighting at night, the captured picture cannot be clear as a whole, and there will always be some blurring;

[0006] Surveillance lenses currently on the market seldom eliminate the stray light of the lens through the optical structure. When the light source is strong or sunny, the lens stray light phenomenon is serious, which makes the actual imaging effect of the lens poor;

[0007] At present, the monitoring lens on the market uses aspherical glass lenses, and less attention is paid to cost issues. Usually, the diameter is larger than 20mm. Due to the processing accuracy problem, the cost of glass aspheric lenses with a diameter larger than 20mm is usually higher.

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