Athermal lens

Abstract

The invention relates to an athermal lens, which adopts a two-piece spherical design. A piece of quartz glass with acid resistance and extremely small thermal expansion coefficient is adopted as a first piece of lens, both the first and the second surfaces of the first piece of lens are spherical surfaces, and a diaphragm is located on the first surface; fluorite is adopted as a second piece of lens, and both surfaces of the lens are spherical surfaces. The principle of the athermal lens is as follows: when being irradiated by laser, a lens is heated to expand, so that the focal length is increased, and as a result, the optical performance is affected; at the moment, the two lenses made of the different materials are used, the refractive index of the two materials can be affected by temperature to decrease; and by scientific calculation, the focal length decreased by the change of the refractive index can counteract the focal length increased by thermal deformation, so that the original focal length can be kept unchanged.

Description

technical field [0001] The invention relates to the field of optics, and is an athermal lens. Background technique [0002] Optical systems usually require stable optical performance within a certain temperature range, and most optical materials have a light-thermal expansion coefficient. As the ambient temperature changes, the refractive index of the optical material, the curvature and thickness of the optical element, and the spacing of the parts will all change. Changes will cause thermal defocusing of the optical system, resulting in poor imaging quality. Therefore, athermal optical systems have become an important research direction for high-precision systems. [0003] The athermal design of the optical system generally uses mechanical, optical, electronic and other technologies to keep the imaging quality of the system stable in a large temperature range. There are usually three methods: electromechanical active, mechanical passive, and optical passive. Although the e...

AI Technical Summary

Problems solved by technology

Although the electromechanical active and mechanical passive systems are easy to implement, they increase the size and weight of the system, and require high adjustment accuracy, which can easily cause optical axis shaking and cause aiming errors; the optical passive athermal system has small size, light weight, and simple structure. , stable optical axis, high reliability, etc.

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