Fixed-focus optical system and lens

Abstract

The invention discloses a fixed-focus optical system, which comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens and a hpotosensitive chip which are sequentially arranged from an object side to a phase side; the first lens has positive focal power; the second lens has negative focal power, and the second lens and the first lens are arranged at an interval; the third lens has positive focal power, and the third lens and the second lens are arranged at an interval; the fourth lens has positive focal power, and the fourth lens and the third lens are arranged at an interval; the diaphragm and the fourth lens are arranged at an interval and the diaphragm is used for limiting the aperture of the light beam; the fifth lens has negative focal power, and the fifth lens and the diaphragm are arranged at an interval; the sixth lens has positive focal power, and the sixth lens and the fifth lens form a cemented lens; the seventh lens has positive focal power, and the seventh lens and the sixth lens are arranged at an interval; and the photosensitive chip and the seventh lens are arranged at an interval, and the photosensitive chip is used for capturing an imaging signal and forming an image. By arranging lens combinations of different structures and reasonably distributing the focal power of each lens, low distortion and high relative illumination of the optical system are realized while high-definition resolution is obtained.

Description

technical field [0001] The invention relates to the technical field of optical lenses, in particular to a fixed-focus optical system and a lens. Background technique [0002] Fixed-focus lenses have the characteristics of low cost and high resolution, and occupy a huge market share in the surveillance, security and video communication fields. The current market has very high requirements for the specifications and performance of fixed-focus surveillance lenses, such as high-definition resolution capabilities, resolutions of 4K and above; low distortion, or even no distortion; high relative illuminance; in order to achieve high-definition resolution and smaller images Distortion, high relative illuminance, most of the existing products on the market use lens structures containing plastic aspheric lenses, however, compared with glass lenses, plastic aspheric lenses have the disadvantages of easy aging and poor stability . Contents of the invention [0003] The present inve...

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Problems solved by technology

For this reason, the present invention proposes a fixed-focus optical system and lens, which can solve the problems of low resolution, high distortion and low relative illuminance of existing lenses

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