CN108761736B

CN108761736B - Light path structure

Info

Publication number: CN108761736B
Application number: CN201810778930.8A
Authority: CN
Inventors: 陆文勇
Original assignee: Beijing Future Orange Network Technology Co ltd
Current assignee: Beijing Future Orange Network Technology Co ltd
Priority date: 2018-07-16
Filing date: 2018-07-16
Publication date: 2023-08-29
Anticipated expiration: 2038-07-16
Also published as: CN108761736A

Abstract

The application provides an optical path structure. The optical path structure comprises, coaxially and sequentially from an object side to an image side: the first lens is a convex-concave lens, one side close to the object space adopts an outer convex surface, and one side far away from the object space adopts an inner concave surface; the second lens is a plano-concave lens, one side close to the object space adopts a plane, and one side far away from the object space adopts an inner concave surface; the third lens is a biconvex lens; and the fourth lens is a concave-convex lens, one side close to the object space adopts an inner concave surface, and one side far away from the object space adopts an outer convex surface. The optical path structure provided by the application has the following beneficial effects: the lens can be applied to ultra-wide angle lenses, the parameters of MTF, point spread function, distortion, chromatic aberration and the like are good, the number of lenses is only four, and the cost is greatly reduced.

Description

Light path structure

Technical Field

The application relates to the field of peripheral products of electronic equipment, in particular to an optical path structure.

Background

With the continuous development and expansion of intelligent hardware of the internet, especially the continuous maturation and increasing demands of panoramic photography, panoramic driving recording and virtual reality technology, the demands for high-quality and low-cost ultra-wide-angle optical lenses are increasing. In recent years, with the rapid development of miniaturized imaging lenses, the application fields of the miniaturized imaging lenses are widened, and the requirements of people on the lenses are diversified. With the shrinking pixel size of the photosensitive element and the development of portable electronic products in the light and thin direction, small wide-angle imaging lenses with high imaging quality are becoming the mainstream in the market.

However, the number of lenses used in the existing wide-angle lens is up to 5-10 under the premise of ensuring imaging quality, and the manufacturing cost is too high.

Disclosure of Invention

The application aims to provide a lens which can reduce the cost of an optical path structure by reducing the number of lenses so as to solve the defects.

In order to achieve the above object, according to one aspect of the present application, there is provided an optical path structure.

The optical path structure comprises, coaxially and sequentially from an object side to an image side:

the first lens is a convex-concave lens, one side close to the object space adopts an outer convex surface, and one side far away from the object space adopts an inner concave surface;

the second lens is a plano-concave lens, one side close to the object space adopts a plane, and one side far away from the object space adopts an inner concave surface;

the third lens is a biconvex lens; and

the fourth lens is a concave-convex lens, an inner concave surface is adopted on one side close to the object space, and an outer convex surface is adopted on one side away from the object space.

Further, a distance between the first lens and the second lens is 4.2mm, a distance between the second lens and the third lens is 3.7mm, and a distance between the third lens and the fourth lens is 3.9mm.

Further, the center thickness of the first lens is 0.8mm, the center thickness of the second lens is 1.3mm, the center thickness of the third lens is 1.6mm, and the center thickness of the fourth lens is 1.7mm.

Further, the refractive index of the first lens is 1.7725, the Abbe number is 49.6, the spherical radius of the outer convex surface is 45.2mm, and the spherical radius of the inner concave surface is 4.7mm.

Further, the refractive index of the second lens is 1.593, the Abbe number is 67.3, and the spherical radius of the concave surface is 14.9mm.

Further, the refractive index of the third lens is 1.651, the Abbe number is 56.2, the spherical radius of the outer convex surface near one side of the second lens is 112.1mm, and the spherical radius of the outer convex surface on the other side is 22.03mm.

Further, the refractive index of the fourth lens is 1.65160, the Abbe number is 58.4, the spherical radius of the outer convex surface is 5.6mm, and the spherical radius of the inner concave surface is 8.2mm.

Further, the optical path structure further comprises an optical filter arranged between the fourth lens and the imaging surface.

Further, the light path structure further comprises a diaphragm arranged between the optical filter and the imaging surface.

Further, the maximum horizontal field angle FOV of the light path structure is up to 150 °.

The optical path structure provided by the application has the following beneficial effects: the optical path structure of the application can be applied to ultra-wide angle lenses, and the parameters of MTF, point spread function, distortion, chromatic aberration and the like are all better, and the number of lenses is only four, thus greatly reducing the cost.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to these drawings for a person having ordinary skill in the art.

FIG. 1 is a schematic diagram of an optical path structure according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an optical path structure according to another embodiment of the present application;

FIG. 3 is a light path diagram of the light path structure of the present application;

FIG. 4 is a schematic diagram of the Modulation Transfer Function (MTF) of the optical path structure of the present application;

FIG. 5 is a schematic view of the defocus MTF of the optical path structure of the present application; when the abscissa is 0, the curve names corresponding to the directions from large to small on the ordinate are respectively: 20 (deg) -sagittal, 0 (deg) -tan, 20 (deg) -tan, 60 (deg) -tan, 45 (deg) -tan, 35 (deg) -sagittal, 93 (deg) -tan, 60 (deg) -sagittal, 93 (deg) -sagittal;

FIG. 6 is a schematic diagram of a distorted field curvature of the optical path structure of the present application; in the left graph, when the ordinate is 70, the curve names corresponding to the directions from small to large (from left to right) are respectively: 0.4700-tagetial, 0.5100-tagetial, 0.5500-tagetial, 0.6100-tagetial, 0.4700-tagitial, 0.6500-tagetial, 0.5100-tagittal, 0.5500-tagitial, 0.6100-tagitial, 0.6500-tagitial; the curve in the right graph is 0.6500;

FIG. 7 is a point diagram of an optical path structure of the present application;

FIG. 8 is a color difference diagram of the optical path structure of the present application; at 60 on the ordinate, the names of the curves corresponding to the directions from small to large (from left to right) on the abscissa are respectively: airy, 0.5100, 0.5500, 0.4700, 0.6100, 0.6500, airy;

reference numerals illustrate:

1. a first lens; 2. a second lens; 3. a third lens; 4. a fourth lens; 5. an imaging surface; 6. a light filter; 7. a diaphragm.

Detailed Description

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe the embodiments of the application herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In the present application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate an azimuth or a positional relationship based on that shown in the drawings. These terms are only used to better describe the present application and its embodiments and are not intended to limit the scope of the indicated devices, elements or components to the particular orientations or to configure and operate in the particular orientations.

Also, some of the terms described above may be used to indicate other meanings in addition to orientation or positional relationships, for example, the term "upper" may also be used to indicate some sort of attachment or connection in some cases. The specific meaning of these terms in the present application will be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, the terms "mounted," "configured," "provided," "connected," "coupled," and "sleeved" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; may be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements, or components. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the accompanying drawings 1-8 in conjunction with examples.

Example 1

The optical path structure shown in fig. 1 includes, in order from an object side to an image side: the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4, the distance between the first lens 1 and the second lens 2 is 4.2mm, the distance between the second lens 2 and the third lens 3 is 3.7mm, and the distance between the third lens 3 and the fourth lens 4 is 3.9mm.

Wherein,,

the first lens 1 is a convex-concave lens, an outer convex surface is adopted on one side close to the object side, an inner concave surface is adopted on one side far away from the object side, the central thickness of the first lens 1 is 0.8mm, the refractive index of the first lens 1 is 1.7725, the Abbe number is 49.6, the spherical radius of the outer convex surface is 45.2mm, and the spherical radius of the inner concave surface is 4.7mm;

the second lens 2 is a plano-concave lens, a plane is adopted on one side close to the object space, an inner concave surface is adopted on one side far away from the object space, the central thickness of the second lens 2 is 1.3mm, the refractive index of the second lens 2 is 1.593, the Abbe number is 67.3, and the spherical radius of the inner concave surface is 14.9mm;

the third lens 3 is a biconvex lens, the central thickness of the third lens 3 is 1.6mm, the refractive index of the third lens 3 is 1.651, the Abbe number is 56.2, the spherical radius of the outer convex surface close to one side of the second lens 2 is 112.1mm, and the spherical radius of the outer convex surface on the other side is 22.03mm; and

the fourth lens 4 is a concave-convex lens, an inner concave surface is adopted on one side close to the object side, an outer convex surface is adopted on one side far away from the object side, the central thickness of the fourth lens 4 is 1.7mm, the refractive index of the fourth lens 4 is 1.65160, the Abbe number is 58.4, the spherical radius of the outer convex surface is 5.6mm, and the spherical radius of the inner concave surface is 8.2mm.

In this embodiment, the first lens 1 is a convex-concave lens, the rear end face adopts an inner concave surface, so that an imaging range of a large field of view can be obtained, the convex surface with smaller radian in the third lens 3 is in front and can be used for correcting residual aberration and systematic chromatic aberration, the fourth lens is a meniscus lens, the concave surface is in front, the front end face adopts an inner concave surface, the rear end face adopts an outer convex surface and can be used for correcting aberration generated by a large field of view, and various aberrations which are not corrected by the front three lenses and shaping light beams. The horizontal view angle of the optical path structure can reach 150 degrees.

Example 2

The optical path structure shown in fig. 2 includes, in order from the object side to the image side: the optical lens comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, an optical filter 6 and a diaphragm 7, wherein the distance between the first lens 1 and the second lens 2 is 4.2mm, the distance between the second lens 2 and the third lens 3 is 3.7mm, and the distance between the third lens 3 and the fourth lens 4 is 3.9mm.

Wherein,,

The filter 6 is arranged between the fourth lens 4 and the imaging surface 5. For limiting the band range of the imaging beam; the imaging range of the optical path structure in the application is a visible light wave band, and the optical filter is adopted to mainly select the optimal imaging wave band aiming at the target, so that the optimal imaging resolution can be obtained.

A diaphragm 7 is arranged between the filter 6 and the imaging plane 5 for limiting the beam aperture of the respective fields of view. Wherein the diaphragm 7 is preferably an aperture diaphragm, the aperture size of which is a fixed aperture size or an adjustable aperture size. The aperture stop whose aperture size can be adjusted can be a mechanically rotated or electronically driven iris.

As shown in fig. 3, an optical path diagram of the optical path structure in the present embodiment is given, and the horizontal angle of view thereof can reach 150 °.

Example 3

In order to verify that the optical path structure provided by the application has superior optical performance, the optical path structure provided by the embodiment 2 is tested by the optical design software ZEMAX, and test results are shown in fig. 4-8, wherein fig. 4-8 are respectively an MTF schematic diagram, an out-of-focus MTF schematic diagram, a distorted field curvature schematic diagram, a point column diagram and a chromatic aberration diagram of the optical path structure of the embodiment 2.

As can be seen from fig. 4, the curves of each field of view in the optical path structure of embodiment 2 are relatively concentrated, and the edge field of view dispersion has less influence on actual imaging;

as can be seen from fig. 5, the optical path structure of embodiment 2 is relatively concentrated in the curves of the important field of view;

as can be seen from fig. 6, the distortion in the optical path structure of embodiment 2 is small;

as can be seen from fig. 7, the point spread function of the optical path structure of embodiment 2 is relatively concentrated in the central position, and the edge dispersion degree is relatively uniform;

as can be seen from fig. 8, the chromatic aberration in the optical path structure of embodiment 2 is superior.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The utility model provides a light path structure, its characterized in that, this light path structure comprises four lenses, and coaxial order includes from object space to image space:

the first lens (1) is a convex-concave lens, an outer convex surface is adopted on one side close to the object space, an inner concave surface is adopted on one side far away from the object space, the central thickness is 0.8mm, the refractive index is 1.7725, the Abbe number is 49.6, the spherical radius of the outer convex surface is 45.2mm, and the spherical radius of the inner concave surface is 4.7mm;

the second lens (2) is a plano-concave lens, a plane is adopted on one side close to the object space, an inner concave surface is adopted on one side far away from the object space, the central thickness is 1.3mm, the refractive index is 1.593, the Abbe number is 67.3, and the spherical radius of the inner concave surface is 14.9mm;

the third lens (3) is a biconvex lens, the central thickness is 1.6mm, the refractive index is 1.651, the Abbe number is 56.2, the spherical radius of the outer convex surface close to one side of the second lens (2) is 112.1mm, and the spherical radius of the outer convex surface on the other side is 22.03mm; and

the fourth lens (4) is a concave-convex lens, an inner concave surface is adopted on one side close to the object space, an outer convex surface is adopted on one side far away from the object space, the central thickness is 1.7mm, the refractive index is 1.65160, the Abbe number is 58.4, the spherical radius of the outer convex surface is 5.6mm, and the spherical radius of the inner concave surface is 8.2mm;

the distance between the first lens (1) and the second lens (2) is 4.2mm, the distance between the second lens (2) and the third lens (3) is 3.7mm, and the distance between the third lens (3) and the fourth lens (4) is 3.9mm; the maximum horizontal field of view FOV is up to 150 °.

2. The light path structure according to claim 1, further comprising a filter (6) disposed between the fourth lens (4) and the imaging surface (5).

3. The light path structure according to claim 2, further comprising a diaphragm (7) arranged between the filter (6) and the imaging plane (5).