CN113671667A

CN113671667A - Ultra-wide-angle infrared confocal lens

Info

Publication number: CN113671667A
Application number: CN202110540972.XA
Authority: CN
Inventors: 苏耀
Original assignee: Suzhou Magu Optical Co ltd
Current assignee: Suzhou Magu Optical Co ltd
Priority date: 2021-05-18
Filing date: 2021-05-18
Publication date: 2021-11-19

Abstract

The invention discloses an ultra-wide-angle infrared confocal lens which comprises a lens barrel, a first lens group, a diaphragm, a second lens group, protective glass and a photosensitive chip, wherein the first lens group is a first lens and a second lens which are sequentially arranged, and the second lens group is a third lens which is sequentially arranged. The first lens is a convex-concave type, the second lens is a convex-concave type, and the third lens is a biconvex type. The focal length range of the first lens group is-3 to-1 mm, and the focal length range of the second lens group is 0.5 to 2 mm. The concave and convex combined structure adopted by each lens can better realize infrared confocal property, ultra-wide angle and simultaneously realize no purple edge by reasonably distributing focal power and selecting resin/glass materials with different dispersion coefficients, the visible light wave band implemented by the invention is 400-940 nm, and the infrared wave band is 780-940 nm.

Description

Ultra-wide-angle infrared confocal lens

Technical Field

The invention relates to the technical field of lenses, in particular to an ultra-wide-angle infrared confocal lens.

Background

In order to meet the requirement of working in day and night environments, the technical specification of infrared confocal is provided in the industry at present, the existing fixed focus lens is difficult to combine the requirements of infrared confocal and ultra-wide angle, the high definition requirement of imaging in a bright and dark environment cannot be met, the purple edge phenomenon is serious in a visible mode, the definition is seriously reduced in a high and low temperature environment, the temperature drift is large, the peripheral brightness of an imaging picture is not large enough, the relative illumination is low, the existing infrared confocal lens generally has the problems of complex structure and large size, and the miniaturization requirement is difficult to meet. The present invention has been made to overcome the above disadvantages.

Disclosure of Invention

The invention provides an ultra-wide-angle infrared confocal lens group which has the advantages of large field angle, small structure, high resolution, high color reduction degree, large aperture, infrared confocal and low cost and is used for overcoming the defects of the prior art.

In order to achieve the purpose, the invention provides the following technical scheme: an ultra-wide angle infrared confocal lens which characterized in that: the lens comprises a lens barrel, a first lens group, a diaphragm, a second lens group, protective glass and a photosensitive chip, wherein the first lens group, the diaphragm, the second lens group, the protective glass and the photosensitive chip are sequentially arranged along an optical axis from an object side to an image side; the diaphragm is positioned between the second lens and the third lens;

the first lens is a convex-concave lens, the second lens is a convex-concave lens, and the third lens is a biconvex lens.

Preferably, the first lens is a concave-convex type, the second lens is a convex-concave type, and the third lens is a biconvex type.

Preferably, the convex-concave first lens, the convex-concave second lens and the biconvex third lens are aspheric resin lenses.

Preferably, the image height of the lens is more than or equal to 3.3 mm.

Compared with the prior art, the invention has the beneficial effects that:

the ultra-wide-angle infrared confocal lens group comprises a lens barrel, a first lens group, a diaphragm and a second lens group which are sequentially arranged from an object to an image side along an optical axis, wherein the lens barrel is arranged, and the focal length ranges of the first lens group and the second lens group are limited; the first lens group comprises a first lens and a second lens which are sequentially arranged from the object side to the image side along the optical axis, and the second lens group comprises a third lens which is sequentially arranged from the object side to the image side along the optical axis; the diaphragm is located between second lens and the third lens, and first lens are concave and convex lens, the second lens is concave and convex lens, the third lens is biconvex type lens. The wide-angle infrared confocal lens solves the problems that the existing wide-angle infrared confocal lens cannot meet the requirements of large field angle, small structure, high resolution, high color reduction degree, large aperture, infrared confocal, low cost and the like, can realize the problems, realizes a larger image plane, contributes to realizing the miniaturization of high resolution and structural volume, and has the large field angle and the infrared confocal.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a graph illustrating the optical transfer function resolution of the present invention;

FIG. 3 is a distortion diagram and a field curvature diagram of the present invention;

fig. 4 is a relative illuminance diagram of the present invention.

In the figure: 1. a first lens group; 11. a first lens; 12. a second lens; 2. a diaphragm; 3. a second lens group; 31. a third lens; 4. a lens barrel; 5. protecting glass; 6. and a photosensitive chip.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a super-wide-angle infrared confocal lens assembly according to an embodiment of the present invention, referring to fig. 1, the super-wide-angle infrared confocal lens assembly includes a lens barrel 4, and a first lens group 1, a diaphragm 2, a second lens group 3, a protective glass 5, and a photo sensor 6 arranged in sequence from an object side to an image side along an optical axis, where the first lens group 1 includes a first lens 11 and a second lens 12 arranged in sequence from the object side to the image side along the optical axis, and the second lens group includes a third lens 31 arranged in sequence from the object side to the image side along the optical axis; the diaphragm 2 is located between the second lens 12 and the third lens 31, the first lens 11 is a concave-convex lens, the second lens 12 is a concave-convex lens, and the third lens 31 is a biconvex lens. The focal length range of the first lens group 1 is-3 to-1 mm, and the focal length range of the second lens group 3 is 0.5 to 2 mm.

The concave-convex first lens 11 has negative focal power, the concave-convex second lens 12 has positive focal power, and the biconvex third lens 31 has positive focal power. The convex-concave first lens 11, the convex-concave second lens 12 and the biconvex third lens 31 are all aspheric resin lenses. The image height of the lens is more than or equal to 3.3 mm.

Wherein 3< TTL/EEF <6, and the related parameters have the following meanings under the conditions:

TTL: the total optical length of the lens group; EFL: is the focal length of the lens group.

The focal length of the first lens 11 is f1, the focal length of the second lens 12 is f2, the focal length of the third lens 31 is f3, the f1 and the f2 are in a relation that-1 is not less than f1/f2 is not less than-0.3, the f2 and the f3 are in a relation that 1 is not less than f2/f3 is not less than 3, and the f3 and the f1 are in a relation that-1.5 is not less than f3/f4 is not less than-0.5.

The Nd1, Nd2, and Nd3 respectively represent the d-light refractive index of the first lens 11, the second lens 12, and the third lens 31, and the Nd1, Nd2, and Nd3 are in the relationship of 1.4-1.6 of Nd1, 1.53-1.73 of Nd2, and 1.4-1.6 of Nd 3.

Vd1, Vd2 and Vd3 respectively represent d-light abbe numbers of the first lens 11, the second lens 12 and the third lens 31, and the Vd1, Vd2 and Vd3 are in the relations of 50-70 Vd 1-35, 18-35 Vd 2-70 and 50-70 Vd 3-70; the aperture value of the ultra-wide-angle infrared confocal lens group is expressed by F/NO, and the total optical length of the lens with the F/NO being more than or equal to 1.6 and less than or equal to 3.9 is expressed by TTL; the TTL is not more than 5.5 mm; the height of the lens image is more than or equal to 3.3 mm.

The aperture value F/NO of the invention satisfies the following conditions: F/NO is more than or equal to 1.6 and less than or equal to 3.9, and the total optical length TTL meets the following conditions: TTL is less than or equal to 5.5mm, image height is more than or equal to 3.3mm, distortion is 0-7.3%, and relative illumination is more than or equal to 48.5%.

Where fig. 2 is a schematic diagram of an optical transfer function, where the abscissa is the line logarithm and the ordinate is the modulation value. The logarithm of the line is 160lp/mm, and the modulation value is more than 30%.

FIG. 3 (right) is a schematic diagram of lens distortion performance, which can be seen, where the abscissa is distortion value and the ordinate is image height value; the distortion is between 0 and 7.3% in all fields of view.

FIG. 3 (left) is a schematic diagram of lens curvature of field, where the abscissa is field value and the ordinate is image height value; within the full field of view, the field curvature is within +/-0.058 mm. The optical structure is light and thin, high in resolution, small in distortion and high in contrast.

The working principle of the invention is as follows:

the super wide-angle infrared confocal lens group comprises a convex-concave first lens 11, a convex-concave second lens 12 and a biconvex third lens 31 which are all aspheric resin lenses. The requirements of the lens on imaging definition and good color performance are met, and meanwhile, the lens is lighter and has good light transmission; the lens is made of a professional optical resin material, so that the temperature drift is minimum by reasonably setting the curvature radius and the center thickness of the lens under the working environment of-40-80 ℃, and the imaging pixels of the imaging system are basically unaffected by temperature change.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides an infrared confocal camera lens of super wide angle, includes lens cone and follows first lens group, diaphragm, second lens group, protection glass, sensitization chip that the optical axis was arranged in proper order from the thing to picture side, its characterized in that: the first lens group comprises a first lens and a second lens which are sequentially arranged from the object side to the image side along the optical axis, and the second lens group comprises a third lens which is sequentially arranged from the object side to the image side along the optical axis; the diaphragm is positioned between the second lens and the third lens;

2. The ultra-wide angle infrared confocal lens of claim 1, wherein the first lens of the concave-convex type is of negative optical power, the second lens of the concave-convex type is of positive optical power, and the third lens of the biconvex type is of positive optical power.

3. The ultra-wide angle infrared confocal lens of claim 1, wherein: the convex-concave first lens, the convex-concave second lens and the biconvex third lens are all aspheric resin lenses.

4. The ultra-wide angle infrared confocal lens of claim 1, wherein: the image height of the lens is more than or equal to 3.3 mm.