Large-view-field large-relative-aperture solar blind ultraviolet optical system

Abstract

The invention discloses a large-view-field large-relative-aperture solar blind ultraviolet optical system. The system is formed by combining thirteen lenses and one ultraviolet narrowband optical filter and is sequentially composed of the first lens with positive focal power, the second lens with negative focal power, the third lens with negative focal power, the fourth lens with positive focal power, the fifth lens with positive focal power, the sixth lens with negative focal power, the seventh lens with positive focal power, an aperture diaphragm, the eighth lens with negative focal power, the ninth lens with positive focal power, the tenth lens with negative focal power, the eleventh focal power with positive focal power, the twelfth lens with positive focal power, the ultraviolet narrowband optical filter, the thirteenth lens with positive focal power and a focal plane detector from an object side to an image side. The work waveband is 260-280nm, F / # is 1.5, the focal length is 7.99mm, the view field is 75.2 degrees, and the length of the whole optical system is 157mm. The optical system realizes high illumination uniformity which is higher than 81.6%, improves the image quality by use of three aspheric surfaces and enables the total optical path lens of the optical system to be shorter. Through overall system movement, the system maintains high-quality imaging within a temperature scope from -40 DEG C to 60 DEG C.

Description

technical field [0001] The invention relates to the technical field of optical system design, in particular to a sun-blind ultraviolet optical system with large field of view and large relative aperture. Background technique [0002] Ultraviolet sensing imaging system is mainly used for biomedical analysis, ozone monitoring, offshore oil monitoring, solar illuminance monitoring, corona discharge detection, criminal investigation, forest fire prevention, space observation, diseased grain removal, mercury lamp disinfection control and disaster weather monitoring and forecasting Wait. When sunlight penetrates the earth's atmosphere, the radiation in the 220-280nm ultraviolet band is strongly absorbed by the ozone layer in the atmosphere. The transparent area of ​​the ultraviolet ordinary optical glass near the surface is generally between 350-2400nm, and the radiation is very weak. There is a so-called "Solar Spectral Blind Zone". When detecting ultraviolet targets in this ba...

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Problems solved by technology

[0003] In the sun-blind band, the ultraviolet optical design is divided into refraction and reflection, among which the reflection loses energy due to central occlusion, which is not good for the detection of weak ultraviolet signals

The materials of the refractive optical system are mainly ultraviolet-transparent optical crystal materials, but most of the materials have poor physical and chemical properties and are not suitable for making lenses

Considering the physical and chemical properties, radiation resistance and processing performance of materials, only two or three materials can be used in the design, such as calcium fluoride, quartz and magnesium fluoride, etc., which is difficult to correct aberrations

In addition, the ultraviolet detection system belongs to the field of weak light detection, which requires high filter transmittance, large relative aperture and high uniformity of illumination on the image plane, which further increases the difficulty of optical system design

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