Design and preparation method of large-focal-depth achromatic micro lens

Abstract

The invention discloses a design and preparation method of a large-focal-depth achromatic micro lens, the micro lens is arranged on a transparent substrate; the method comprises the following steps: determining the focal length and the working wave band of the micro lens; determining a material selected by the transparent substrate, and enabling the dispersion of the transparent substrate to be lower than a preset value; setting the geometric parameters of the surface profile of the surface of the micro lens, wherein the surface profile of the surface of the micro lens comprises a spherical surface at the center part and a tangent plane at the outer side part, and the spherical surface and the tangent plane form a smooth surface; and manufacturing and forming the micro lens on the surface of the transparent substrate according to the geometric parameters. According to the invention, by adopting a mode of combining the spherical lens and the axial prism, the defects of a traditional lens and a super-structure lens are overcome, and the functions of high efficiency, large focal depth, achromatic focusing and the like can be realized in a visible light wave band; the device has the remarkable advantages of simple design principle, no need of massive calculation, low processing cost, high preparation efficiency, short period and the like.

Description

technical field [0001] The invention relates to the technical field of optical lenses, in particular to a design and preparation method of an achromatic microlens with a large focal depth. Background technique [0002] Optical lenses are widely used in modern human life, and can be used in mobile phones, cameras, microscopes, lithography machines, etc. However, traditional optical spherical lenses face a series of problems such as spherical aberration, coma, astigmatism, and chromatic aberration. In particular, the existence of chromatic aberration will seriously reduce the image quality. In order to achieve achromatic focusing, traditional achromatic lenses are often only aimed at several fixed wavelengths, and the lens group is constructed by using multiple lenses, which is not only large in size, heavy in weight, and limited in application scenarios, but also cannot achieve continuous achromatic chromatic aberration. [0003] In recent years, the emergence of achromati...

AI Technical Summary

Problems solved by technology

Based on the resonance effect of subwavelength nanostructure units, metalenses can achieve achromatic focusing of incident light of different wavelengths, and have the advantages of small size, light weight, and easy integration; however, in the design process, the nanostructure array needs to be A large number of configurations and simulations, the design is complex, the calculation is large, and the production efficiency is low

On the other hand, since the metalens adopts the equivalent continuous principle, there is inevitably a scattering effect, which reduces the achromatic focusing efficiency; in addition, most metalenses use anisotropic structural units, which are sensitive to the polarization of the incident light. Further reducing its scope of application

Not only that, in terms of processing and preparation, the sub-wavelength fine structure (large aspect ratio) of the achromatic meta-lens requires high-precision micro-nano preparation processes such as electron beam exposure and atomic layer deposition. The processing cycle is long, the process is complicated, and the price is expensive. , cannot be prepared in a large size, and cannot be applied to large-scale production so far

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