CN219320570U

CN219320570U - Light-weight long exit pupil eyepiece

Info

Publication number: CN219320570U
Application number: CN202320485201.XU
Authority: CN
Inventors: 贾耘; 戴赋贵; 张增强; 张洪升; 谭勇
Original assignee: Kunming Nan Xu Photoelectric Technologies Co ltd
Current assignee: Kunming Nan Xu Photoelectric Technologies Co ltd
Priority date: 2023-03-14
Filing date: 2023-03-14
Publication date: 2023-07-07
Anticipated expiration: 2033-03-14

Abstract

The utility model discloses a lightweight long-exit pupil eyepiece, which relates to the technical field of optical eyepieces, and comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object space to an image space, wherein diopter of the first lens is negative, an object side surface is a concave surface, and an image side surface is a concave surface; the diopter of the second lens is positive, the object side surface is a convex surface, and the image side surface is a convex surface; the diopter of the third lens is positive, the object side surface is a convex surface, and the image side surface is a concave surface; the diopter of the fourth lens is positive, the object side surface is convex, the image side surface is convex, the eyepiece of the utility model adopts an aspheric lens and glass-plastic mixed lens combination mode, the total optical eyepiece consists of 4 lenses, the number of lenses is small, the structure is simple, the reasonable distribution focal power realizes the performance requirements of long exit pupil, large visual field and the like, and the eyepiece realizes the vision adjustment through integral focusing; the eyepiece has large magnification, large field of view, long exit pupil distance, light weight and higher imaging quality.

Description

Light-weight long exit pupil eyepiece

Technical Field

The utility model relates to the technical field of optical eyepieces, in particular to a lightweight long-exit pupil eyepiece.

Background

The long exit pupil ocular has important roles in the aspects of sighting device, handheld observers and the like, for example, the uncooled infrared detector needs to use 16 times of long exit pupil ocular. Most of the existing long-pupil ocular adopts a traditional ocular optical system, the exit pupil distance is long, and the existing long-pupil ocular rarely adopts an aspheric surface and uses common optical glass. The problems with conventional long exit pupil eyepieces are heavy weight and bulky. The utility model therefore proposes a lightweight long exit pupil eyepiece.

Disclosure of Invention

In order to overcome the problems in the background technology, the utility model provides a lightweight long-exit pupil eyepiece, which adopts a material combination mode of mixing optical plastic and optical glass to lighten the weight of a lens, adopts an aspheric technology to reduce the thickness of the lens, lightens the whole weight of the eyepiece and reduces the outline dimension of an optical system of the eyepiece, thereby solving the problems of heavy weight and large volume of the traditional long-exit pupil eyepiece.

In order to achieve the above purpose, the utility model is realized by the following technical scheme:

a light-weight long exit pupil eyepiece comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object space to an image space, wherein diopter of the first lens is negative, an object side surface is a concave surface, and an image side surface is a concave surface; the diopter of the second lens is positive, the object side surface is a convex surface, and the image side surface is a convex surface; the diopter of the third lens is positive, the object side surface is a convex surface, and the image side surface is a concave surface; the diopter of the fourth lens is positive, the object side surface is a convex surface, and the image side surface is a convex surface.

Further, the first lens and the fourth lens are optical glass lenses, and the second lens and the third lens are optical plastic lenses.

Further, the second lens, the third lens and the fourth lens are mirror surfaces of a higher aspheric surface.

Further, the light-weight long exit pupil eyepiece is a movable fixed focus eyepiece.

Compared with the prior art, the utility model has the beneficial effects that:

the lens group of the utility model adopts the form of combining optical glass and optical plastic, a good balance point is found between imaging quality and the weight of an ocular optical element, and meanwhile, the aspherical technology is adopted to reduce the thickness of the lens, so that the system ensures the image quality, simplifies the optical structure form, reduces the volume and weight of the whole ocular, and is more convenient for use, operation and application.

Drawings

For the purpose of clearly illustrating the technical solutions in the embodiments of the present utility model, the drawings that are required to be used in the description of the embodiments will be described.

FIG. 1 is a schematic view of the optical structure of a lightweight long exit pupil eyepiece of the present utility model;

FIG. 2 is a graph of the transfer function of the lightweight long exit pupil eyepiece of the present utility model at 20 ℃;

FIG. 3 is a plot of diffuse plaques at 20 ℃ for a lightweight long exit pupil eyepiece of the present utility model;

fig. 4 is a graph of distortion of the lightweight long exit pupil eyepiece of the present utility model at 20 ℃.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present utility model more apparent, preferred embodiments of the present utility model will be described in detail below with reference to the accompanying drawings, so as to facilitate understanding of the skilled person.

This example is an example of the utility model applied to a refrigerated infrared detector with a resolution of 1024 x 768, a pixel size of 7.75 μm, an amplification factor of 16, and an application in the range of-40 ℃ to +50 ℃.

Fig. 1 shows the focal length f of the present utility model: 15.6mm, magnification: 16, exit pupil distance: 60mm, weight: referring to fig. 1, a light-weight long exit pupil eyepiece with an optical system diagram of 60g comprises a first lens 1, a second lens 2, a third lens 3 and a fourth lens 4 which are sequentially arranged from an object side to an image side, wherein diopter of the first lens 1 is negative, an object side is a concave surface, and an image side is a concave surface; the diopter of the second lens element 2 is positive, the object-side surface is convex, and the image-side surface is convex; the diopter of the third lens 3 is positive, the object side surface is a convex surface, and the image side surface is a concave surface; the fourth lens element 4 has a positive refractive power, a convex object-side surface and a convex image-side surface.

The light-weight long exit pupil eyepiece is a movable fixed Jiao Mujing, the first lens 1 is a biconcave negative lens, light rays can be effectively contracted, the outline size of the eyepiece is reduced, the second lens 2 is a biconvex positive lens, field curvature can be effectively corrected, the third lens 3 is a convex concave positive lens, light rays can be effectively contracted, spherical aberration and distortion can be effectively corrected, and the fourth lens 4 is a biconvex positive lens, light rays can be effectively contracted, distortion and chromatic aberration can be effectively corrected.

Referring to fig. 1, the first lens 1 and the fourth lens 4 are optical glass lenses, the second lens 2 and the third lens 3 are optical plastic lenses, and the optical glass for the first lens 1 and the fourth lens 4 of the eyepiece has the characteristics of high density and high refractive index, and can effectively improve the imaging quality of the eyepiece; the second lens 2 and the third lens 3 have large diameters, optical plastics are adopted for reducing the weight of the ocular lens, the optical plastics have the characteristics of low density and low refractive index, and a good balance point is found between the imaging quality and the weight of the ocular lens optical element by adopting a mode of combining optical glass and optical plastics.

Referring to fig. 1, the surfaces of the second lens 2, the third lens 3 and the fourth lens 4 are aspheric, and more specifically, to improve the image quality and improve the influence of temperature variation on the image quality, the surfaces of the second lens, the third lens and the fourth lens are aspheric with higher order

Table 1 lists the aspherical coefficients of the surface S4 of the second lens (2), the surface S5 of the third lens (3), and the surface S7 of the fourth lens (4).

Surface of the body	K	A	B	C	D
						S4	0	2.00159E-05	-1.65212E-07	1.36915E-09	1.39895E-12
S5	0	1.71129E-05	1.58767E-08	1.75871E-11	-9.13074E-14
						S7	0	3.87065E-05	-1.62667E-08	-4.45018E-11	2.98728E-13

Table 1: aspheric coefficients of surfaces S4, S5, S7

The above lens even aspherical equation is defined as follows:

the embodiment achieves good imaging quality by adopting 3 aspheric surfaces, has good manufacturability, can reduce the number of lenses and reduces the cost.

Fig. 2 to 4 are diagrams of imaging optical simulation data of the light-weight long exit pupil eyepiece at 20 ℃ in the present embodiment, wherein fig. 2 is an optical transfer function (MTF) graph, the horizontal axis is logarithmic line per millimeter (lp/mm), the vertical axis is contrast value, fig. 3 is a point column graph, and fig. 4 is a distortion graph. From the graph curves of fig. 2 to 4, it can be seen that the MTF, the root mean square value of the diffuse speck and the distortion at the temperature of 20 ℃ are all in the standard range, and the system requirements are satisfied.

Therefore, the light long exit pupil eyepiece has good imaging quality.

The foregoing description is only a preferred embodiment of the present utility model, but the scope of the present utility model is not limited thereto, and any person skilled in the art, who is within the scope of the present utility model, should make equivalent substitutions or modifications according to the technical solution of the present utility model and the inventive concept thereof, and should be covered by the scope of the present utility model.

Claims

1. A lightweight long exit pupil eyepiece characterized by: the light-weight long exit pupil eyepiece comprises a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) which are sequentially arranged from an object space to an image space, wherein diopter of the first lens (1) is negative, an object side surface is a concave surface, and an image side surface is a concave surface; the diopter of the second lens (2) is positive, the object side surface is a convex surface, and the image side surface is a convex surface; the diopter of the third lens (3) is positive, the object side surface is a convex surface, and the image side surface is a concave surface; the diopter of the fourth lens (4) is positive, the object side surface is a convex surface, and the image side surface is a convex surface.

2. The lightweight long exit pupil eyepiece of claim 1, wherein: the first lens (1) and the fourth lens (4) are optical glass lenses, and the second lens (2) and the third lens (3) are optical plastic lenses.

3. The lightweight long exit pupil eyepiece of claim 1, wherein: the second lens (2), the third lens (3) and the fourth lens (4) are mirror surfaces of high-order aspheric surfaces.

4. The lightweight long exit pupil eyepiece of claim 1, wherein: the light long-exit pupil ocular is a movable fixed focus ocular.