Thin Fresnel lens with a short focal length

A Fresnel lens and short focal length technology, applied in the field of optical instruments, can solve the problems of increasing reflection loss, increasing system size and cost, and increasing focal length

Inactive Publication Date: 2014-05-21
青岛哈工大科创工业技术研究院
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Fresnel lens designed using the light refraction principle of traditional geometric optics, its focal diameter ratio (the ratio of the focal length F of the lens to the diagonal line of the condenser lens) is usually controlled between 0.8 and 1.4. If the focal length ratio is too

Method used

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  • Thin Fresnel lens with a short focal length
  • Thin Fresnel lens with a short focal length

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0020] Example 1:

[0021] figure 1 The plan layout structure of the present invention is shown. The overall shape of the lens is square, with a plano-convex lens projection 3 in the middle, a refractive projection 2 on the periphery of the plano-convex lens projection 3, and a reflective projection 1 on the periphery of the refractive projection 2 The number of rings of the refractive protrusion 2 and the reflective protrusion 1 can be determined according to actual needs. In order to achieve a short focal length in the present invention, in this embodiment, a reflective convex structure is adopted on the periphery of the lens. Attached figure 2 , The lens structure provided with the reflective protrusion 1 is further described. figure 2 It is a cross-sectional view of the lens structure, showing only the upper part. Among them, it includes a base plane 4 and a condensing surface 5 that are parallel to each other. The condensing surface 5 is provided with a condensing proje...

Example Embodiment

[0022] Example 2:

[0023] Compared with the first embodiment, this embodiment is different in that: a reflective film is provided on the inclined surface 11 of the reflective protrusion 1, and the light is reflected on the reflective film on the inclined surface 11. The slope requirement is not high, even if the incident angle is smaller than the critical angle of total reflection, it can still play a condensing effect and shorten the focal length.

Example Embodiment

[0024] Example 3:

[0025] Compared with the first embodiment, this embodiment is different in that the overall shape of the lens is circular.

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Abstract

The invention discloses a thin Fresnel lens with a short focal length. The thin Fresnel lens comprises a reference plane and a light-condensing plane, wherein the light-condensing plane is provided with a light-condensing projection formed by an inclined surface and a vertical surface. The light-condensing projection comprises a reflection projection performing reflection on the inclined surface. The light-condensing plane of the Fresnel lens is provided with the reflection projection such that when light perpendicular to the reference plane is irradiated to the inclined surface of the reflection projection, total reflection occurs on the inclined surface of the reflection projection. And then, light is focused at the focal point of the lens through refraction, thereby effectively shortening the focus length of the lens.

Description

[0001] technical field [0002] The invention belongs to the field of optical instruments, and in particular relates to a thin Fresnel lens with a short focal length. Background technique [0003] Fresnel lenses are widely used in concentrating photovoltaic systems. In order to improve optical efficiency, Fresnel lenses are required to have a large lighting area. Therefore, it is necessary to provide a large-size Fresnel lens. The light is refracted by the Fresnel lens and converges to the focal point of the Fresnel lens. When the focal length is constant, the farther the outer tooth surface from the center of the lens is, the greater the inclination angle is, and the reflection loss increases accordingly. In order to reduce the reflection loss, increasing the size of the Fresnel lens also needs to increase the focal length, but this will increase the overall size of the concentrated solar system and increase the difficulty of control, thereby increasing the system cost. T...

Claims

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Application Information

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IPC IPC(8): G02B3/08G02B1/10
Inventor 田兆硕申海亭付世友孙正和杨茂华孙国栋
Owner 青岛哈工大科创工业技术研究院
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