Micro lens for realizing bifocal focusing

Abstract

The invention discloses a micro lens for realizing bifocal focusing. The micro lens is characterized in that the micro lens comprises a cylindrical lens made of a uniform dielectric material, the incident plane of the lens is a plane, and the emergent plane of the lens is a concave surface with a stepped grating structure; the stepped grating is provided with a first step grating area corresponding to a focal length f1 and a second step grating area corresponding to a focal length f2 from the incident surface to the emergent surface, wherein f1 is less than f2; and a focus corresponding to the first step grating area is lower than a focus corresponding to the second step grating area, and the interface of the first step grating area and the interface of the second step grating area intersect at one point in the axial direction. The plano-concave lens designed by the invention can realize bifocal focusing at the same time, and effectively reduce the dispersion degree of focal spots so that the focusing is more uniform.

Description

Technical field [0001] The present invention belongs to the field of double focus microlenses, and more particularly to a microlens that realize a double-focus aggregation. Background technique [0002] The focus of the lens has broad application prospects in the fields of optical imaging and photolithography. When the grating period is less than the working wavelength, an equivalent negative refractive index can be obtained according to the sub-wavelength beam negative refractive refractive lens, and the radial polarization light, rotary polarization light and the generalized column vector beam can be superior. Focus. Effect, but the focus focus lens focus focus is large and the energy distribution is uneven, and does not meet the requirements of industrial production. [0003] Through the study, it is found that there is a longer flat step in the structural manner corresponding to the focal length, and the rays emitted from the long-term step do not refer to the mass of the foc...

AI Technical Summary

Problems solved by technology

When the grating period is smaller than the working wavelength, the equivalent negative refractive index can be obtained. The sub-wavelength beam negative refraction lens designed based on this principle can form excellent focusing for radially polarized light, hand-polarized light and generalized cylindrical vector beam. effect, but the focus of the bifocal focusing lens has a large degree of dispersion and uneven energy distribution, which cannot meet the requirements of industrial production

[0003] Through the research, it is found that in the structure with bifocal lens, there is a long flat step at the structural boundary corresponding to the focal length, and the light exiting through the long step will not be refracted, which will affect the quality of the focus field

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