Variable focal length optical system

Abstract

The invention discloses a variable focal length optical system. A first lens group, a second lens group, a diaphragm, a third lens group, a fourth lens group and a light sensing chip are successivelyarranged from the object face to the image face. The first lens group can be fixed relative to the image face. The focal length of the first lens group is positive. The first lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are successively arranged from the object face to the image face. The focal length of the second lens group is negative. The second lens group comprises a seventh lens, an eighth lens, a ninth lens and a tenth lens. The focal length of the third lens group is positive. The third lens group comprises an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens. The focal length of the fourthlens group is positive. The fourth lens group comprises a fifteenth lens and a sixteenth lens. According to the invention, the optical system is high in resolution, big in image face, high in multiplying power and simple in structure.

Description

【Technical Field】 [0001] The invention relates to an optical system, in particular to a zoom optical system. 【Background technique】 [0002] The zoom lens is widely used in people's daily life, especially in the fields of security monitoring, and there is an increasing demand for lenses for wide-angle and telephoto applications. [0003] The current market is developing towards high resolution and super magnification. In order to obtain better imaging quality, the use of chips with larger pixels and more pixels is one of the fundamental ways to solve the problem, but the current security monitoring and road condition monitoring The device has the following disadvantages: [0004] 1. The infrared at the short focal end is not confocal. When there are some lights at night, the captured picture cannot be clear as a whole, and some corners will always be blurred; large-magnification lenses on the market generally have low pixels, and the resolution is mainly 720P and 1080P; [0005] 2. A...

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Problems solved by technology

[0004] 1. Infrared at the short-focus end is not confocal. When there is some lighting at night, the captured picture cannot be clear as a whole, and some corners will always be blurred; large magnification lenses on the market generally have low pixels, and the resolution is mainly 720P and 1080P;

[0005] 2. At present, the chips used by the mainstream surveillance lenses on the market are relatively small, and the pixels of the chips are small. The image plane of the 1080P lens is mainly 1 / 2.8″, and the effective imaging surface is 1 / 2.8″ with a diagonal line of 6.2mm. The CMOS chip has a pixel size of only 2.8μm, and the resolution is not very high; in a dark environment, the shooting quality is not good;

[0006] 3. Ordinary zoom lenses are often not compatible with large magnification and volume. The increase in magnification will also cause a sharp change in lens volume. Currently, surveillance lenses with a zoom ratio of 50 times or more on the market have a maximum diameter of more than 100mm;

[0007] 4. At present, the higher magnification lens of DC is prone to lens shake when used at the telephoto end, and it is difficult to shoot a stable picture, so there is an urgent need for the lens to have an anti-shake function;

[0008] 5. At present, the monitoring lens needs to be confocal with infrared and visible light at the wide-angle end. Most of the monitoring lenses on the field are non-infrared confocal lenses. When there is some lighting at night, the captured picture cannot be clear as a whole, and there will always be some blurring. Even if some lenses achieve infrared confocal, they will increase the purple fringing

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