CN115202031A - An eyepiece optical system with a 90-degree rotation - Google Patents

Abstract

The invention relates to the technical field of optics, in particular to an eyepiece optical system with a 90-degree image transfer, comprising a diaphragm, a first lens, a turning prism, a second lens, a third lens, a fourth lens and an image side, the diaphragm , the first lens, the turning prism, the second lens, the third lens, the fourth lens and the image side are arranged in order from front to back along the optical axis direction, and the second lens and the third lens are sequentially arranged from top to bottom along the optical axis direction Set and combine into a cemented lens, the first lens and the third lens have positive refractive power, the second lens and the fourth lens have negative refractive power, with large field of view, small distortion, small occlusion, simple optical structure, etc. Features, imaging quality can meet current needs.

Description

An eyepiece optical system with a 90-degree rotation

technical field

The invention relates to the technical field of optics, in particular to an eyepiece optical system with a 90-degree image transfer.

Background technique

With the widespread application of optoelectronic technology in individual soldier equipment, a large number of handheld, head-mounted, gun sights, unmanned loads and other optoelectronic equipment have been continuously developed and distributed to troops. Low-light night vision glasses based on image intensifiers have been upgraded from the second and a half generations to the third and even fourth generations, and the structure also includes a variety of monocular monocular, binocular monocular, and binocular binocular. At the same time, with the requirements for digitization, informatization, and intelligence of optoelectronic equipment, night vision glasses based on low-light imaging technology have shined in recent years, and have been extended to handheld observation, gun sighting and other equipment. However, in low-visibility environments such as smoke, clouds and fog, and in completely dark conditions such as underground spaces, individual soldier equipment based on low-light and low-illumination technologies will greatly reduce the ability to detect and identify targets. Adding infrared or short-wave infrared optical channels to low-light and low-illumination equipment will greatly improve all-weather reconnaissance, camouflage identification, and laser perception capabilities in harsh environments.

But for the existing low-light or low-illumination observation equipment, how to fuse the obtained infrared or short-wave infrared image with the low-light or low-illumination image becomes a real problem. There is a need for a new technique that enables observers to observe desired infrared or short-wave infrared images without compromising low-light or low-light image viewing.

Based on this, the present invention provides an eyepiece optical system with a 90-degree turn image, which can couple infrared or short-wave infrared images into low-light or low-illumination observation equipment through the optical system, as an effective technical means to achieve fusion display, Enhance the recognition effect of the target.

SUMMARY OF THE INVENTION

(1) Technical problems solved

Aiming at the deficiencies of the prior art, the present invention provides an eyepiece optical system with a 90-degree image transfer.

(2) Technical solutions

In order to achieve the above object, the present invention provides the following technical solutions: a 90-degree image-rotating eyepiece optical system, comprising a diaphragm, a first lens, a turning prism, a second lens, a third lens, a fourth lens and an image square, so The diaphragm, the first lens, the turning prism, the second lens, the third lens, the fourth lens and the image side are arranged from front to back in the direction of the optical axis, and the second lens and the third lens are arranged from the top along the direction of the optical axis The first lens and the third lens have positive refractive power, the second lens and the fourth lens have negative refractive power, the cemented lens has positive refractive power, and the first lens and the third lens have positive refractive power. The outermost side of a lens is provided with an exit pupil, and the field angle of the eyepiece optical system is between 25 degrees and 52 degrees.

Preferably, the improvement of the present invention is that the diameter of the exit pupil is between 0.8-1.5 mm.

Preferably, the improvement of the present invention is that the distance between the exit pupil and the first lens is less than 2 mm.

Preferably, the improvement of the present invention is that the distance from the center of the turning prism to the image side is between 13-20 mm.

Preferably, the improvement of the present invention is that the focal length of the first lens is f1, and the ratio of the first lens to the focal length f' of the eyepiece optical system satisfies the following relationship: 2<|f1/f'|<3.5.

Preferably, the improvement of the present invention is that the focal length of the cemented lens is fj, and the ratio to the focal length f' of the eyepiece optical system satisfies the following relationship: 0.5<|fj/f'|<0.9.

(3) Beneficial effects

Compared with the prior art, the present invention provides an eyepiece optical system with a 90-degree image transfer, which has the following beneficial effects:

The eyepiece optical system with a 90-degree turn image has the characteristics of large field of view, small distortion, small occlusion, and simple optical structure, and the imaging quality can meet the current needs.

Description of drawings

Fig. 1 is the structure and optical path schematic diagram of the present invention;

Fig. 2 is MTF curve diagram of the present invention;

Fig. 3 is the distortion diagram of the present invention;

In the figure: 1, entrance pupil; 2, first lens; 3, turning prism; 4, second lens; 5, third lens; 6, fourth lens; 7, image side.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to Figure 1-3, an eyepiece optical system with a 90-degree relay image, including a diaphragm, a first lens 2, a turning prism 3, a second lens 4, a third lens 5, a fourth lens 6 and an image square 7, The diaphragm, the first lens 2, the turning prism 3, the second lens 4, the third lens 5, the fourth lens 6 and the image side 7 are arranged in order from front to back along the optical axis direction. The three lenses 5 are arranged in sequence from top to bottom along the optical axis to form a cemented lens, the first lens 2 and the third lens 5 have positive refractive power, and the second lens 4 and the fourth lens 6 have negative refractive power , the cemented lens has positive refractive power, the outermost of the first lens 2 is provided with an exit pupil, and the field angle of the eyepiece optical system is between 25 degrees and 52 degrees.

Preferably, the diameter of the exit pupil is between 0.8-1.5 mm.

Preferably, the distance between the exit pupil and the first lens 2 is less than 2 mm.

Preferably, the distance from the center of the turning prism 3 to the image side 7 is between 13-20 mm.

Preferably, the focal length of the first lens 2 is f1, and the ratio with the focal length f' of the eyepiece optical system satisfies the following relationship: 2<|f1/f'|<3.5.

Preferably, the focal length of the cemented lens is fj, and its ratio to the focal length f' of the eyepiece optical system satisfies the following relationship: 0.5<|fj/f'|<0.9.

In the content of this application, f1 is the focal length of the fourth lens 6, which is 25 mm, and f' is the focal length of the eyepiece optical system, which is 9 mm.

The first lens 2 is a positive refractive power lens, and its function is to finally convert the light from the image side 7 into parallel light for output.

The turning prism 3 is to turn the optical path by 90 degrees. In this application, the turning prism 3 can be replaced by a reflecting mirror.

The second lens 4 and the third lens 5 are cemented to form a cemented lens with positive refractive power, which functions to condense the light from the image side 7 and improve the aberration and distortion of the eyepiece optical system at the same time.

The fourth lens 6 is a negative refractive power lens, and its function is to shape the light coming from the image side 7 .

The optical materials used in the entire eyepiece optical system are commonly used glass, and the processing cost is low.

The optical system diagram of this embodiment is shown in Figure 1;

The MTF resolution curve of this embodiment is shown in FIG. 2 , where the abscissa represents the spatial frequency of line pairs/mm, and the ordinate represents the MTF value. It can be seen from FIG. 2 that this embodiment exhibits good contrast in the spatial frequency of 661p/mm in the entire imaging area, which meets the requirements of human eye observation.

The optical distortion diagram of this embodiment is shown in FIG. 3 , and the maximum distortion is only 1.03%.

The eyepiece optical system of a 90-degree relay of the present invention has a total of 4 lenses, a prism, and a total of ten surfaces, and the curvature radius, the center thickness of the lens, the center distance of the lens, and the refractive index of the lens meet the following conditions:

In the description herein, it should be noted that relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities or that there is any such actual relationship or sequence between operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus.

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

Claims (6)

1. An eyepiece optical system with a 90-degree image transfer, comprising a diaphragm, a first lens (2), a turning prism (3), a second lens (4), a third lens (5), and a fourth lens (6) and image side (7), characterized in that: the diaphragm, the first lens (2), the turning prism (3), the second lens (4), the third lens (5), the fourth lens (6) and the The image side (7) is sequentially arranged from front to back along the optical axis direction, the second lens (4) and the third lens (5) are sequentially arranged and combined from top to bottom along the optical axis direction to form a cemented lens, and the first lens (2) and the third lens (5) have positive refractive power, the second lens (4) and the fourth lens (6) have negative refractive power, the cemented lens has positive refractive power, the first lens (2) An exit pupil is arranged on the outermost side, and the field angle of the eyepiece optical system is between 25 degrees and 52 degrees. 2 . The eyepiece optical system of claim 1 , wherein the diameter of the exit pupil is between 0.8-1.5 mm. 3 . 3 . The eyepiece optical system with 90-degree relay image according to claim 2 , wherein the distance between the exit pupil and the first lens ( 2 ) is less than 2 mm. 4 . 4 . The eyepiece optical system with 90-degree relay image according to claim 3 , wherein the distance from the center of the turning prism ( 3 ) to the image side ( 7 ) is between 13-20 mm. 5 . 5. The eyepiece optical system of a 90-degree relay image according to claim 4, wherein the focal length of the first lens (2) is f1, and the ratio with the focal length f' of the eyepiece optical system satisfies the following relationship : 2<f1/f'|<3.5. 6. The eyepiece optical system of claim 5, wherein the focal length of the cemented lens is fj, and the ratio with the focal length f' of the eyepiece optical system satisfies the following relationship: 0.5<| fj/f'|<0.9.

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