Dual exit pupil eyepiece optical system

Abstract

The application discloses a double-pupil eyepiece optical system, which is composed of a first lens, a second lens, a third lens and a micro display screen in sequence along an optical axis from an eye to the micro display screen; the first lens is a cemented positive lens and is composed of a biconvex positive lens and a biconcave negative lens in sequence from the eye to the micro display screen, the second lens is a biconcave plastic aspherical negative lens, and the third lens is a biconvex glass positive lens; first, the glass material is adopted for the first lens, so that the environmental adaptability of the eyepiece is improved; second, the aspherical plastic lens is adopted for the lens, so that the imaging quality of the eyepiece is improved and the weight of the whole eyepiece is reduced; third, the eyepiece has two exit pupil distances, so that the eyepiece can be used in front of a sighting device; the second exit pupil distance is greater than 40 mm, and the exit pupil diameter is greater than 6 mm, so that the high eye point requirement of a gun sighting eyepiece can be met; and fourth, only four lenses are adopted for the whole system, so that the structure form is simple and a structure lens barrel is easy to make.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical systems, in particular to a dual-pupil eyepiece optical system. BACKGROUND

[0002] With the continuous development of individual equipment, head-mounted glasses, sighting scopes and the like are also expanding in the direction of informatization, intelligentization, light weight, multi-purpose and the like. In particular, in special environmental conditions such as a battlefield, a soldier can use an individual sighting device as an observation mirror, a gun sight and a front sight.

[0003] However, a general gun sighting scope requires a long exit pupil distance, and an eyepiece for a front sight generally requires a large exit pupil diameter. The existing eyepieces are generally not shared, and therefore, a dual-pupil eyepiece optical system is proposed to solve the above-mentioned problems. SUMMARY

[0004] The present application aims to provide a dual-pupil eyepiece optical system to solve the problems mentioned in the background.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0006] A dual-pupil eyepiece optical system, the optical system is composed of a first lens, a second lens, a third lens and a micro display screen in order along the optical axis from the eye to the micro display screen; the first lens is a cemented positive lens, and is composed of a biconvex positive lens and a biconcave negative lens in order from the eye to the micro display screen, the second lens is a biconcave plastic aspherical negative lens, and the third lens is a biconvex glass positive lens.

[0007] The ratio of the focal length of the first lens to the focal length of the entire lens satisfies the following relationship:

[0008] 0.3 < |f1 / f| < 1

[0009] Wherein, f is the focal length of the entire lens, and f1 is the focal length of the first lens.

[0010] As a further scheme of the present application, the first lens adopts a glass lens, which improves the environmental adaptability of the eyepiece.

[0011] As a further scheme of the present application, the other side of the first lens is provided with a second entrance pupil, and the other side of the second entrance pupil is provided with a first entrance pupil.

[0012] As a further scheme of the present application, the center thickness of the biconvex lens of the cemented positive lens is 6.1mm, and the center thickness of the biconcave lens is 1.1mm; the materials of the cemented positive lens are heavy flint glass and heavy lanthanum flint glass, respectively.

[0013] As a further scheme of the present application: the central thickness of the plastic aspheric negative lens is 2.2mm; the material of the plastic aspheric negative lens is PMMA, E48R, K26R, F52R, APL5014DP, PAL5514ML, ep5000; the aspheric coefficients of the plastic aspheric negative lens are A=-1.2292151E-5, B=2.7596927-10, C=-3.2466247E-11, D=7.7502617E-14.

[0014] As a further scheme of the present application: the diameters of the first and second entrance pupils are between 7.5mm and 9.5mm.

[0015] As a further scheme of the present application: the optical system is arranged inside the eyepiece barrel, the outer side of the eyepiece barrel is provided with an eyepiece frame, the outer side of the eyepiece frame is provided with a lens seat, one end of the eyepiece frame is provided with a socket, the lens seat is provided with a through slot, the through slot is provided with a plug rod, one end of the plug rod is arranged inside the socket, the other end of the plug rod passes through the through slot and is connected with a plug block, and the plug rod is used in cooperation with the socket.

[0016] As a further scheme of the present application: two groups of clamping rods are arranged on the outer wall of the plug rod, and a plurality of groups of clamping grooves are arranged on the outer wall of the lens seat, the clamping grooves are arranged equidistantly on the outer wall of the lens seat, and the clamping rods are used in cooperation with the clamping grooves.

[0017] As a further scheme of the present application: the other end of the eyepiece frame is provided with a fixing bolt, the outer wall of the eyepiece barrel is provided with a plurality of groups of positioning holes, the positioning holes are arranged equidistantly on the outer wall of the eyepiece barrel, an inner thread is arranged on the inner wall of each of the positioning holes, and the inner thread is used in cooperation with the thread on the fixing bolt.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] First, the lens is made of glass material, which improves the environmental adaptability of the eyepiece.

[0020] Second, the lens is made of an aspheric plastic lens, which improves the imaging quality of the eyepiece and reduces the weight of the entire eyepiece, and the batch molding cost is much lower than that of the glass lens.

[0021] Third, the eyepiece of the present application has two exit pupil distances, the first exit pupil distance is greater than 20mm and the exit pupil diameter is greater than 12mm, which can be used in front of the sighting eyepiece; the second exit pupil distance is greater than 40mm and the exit pupil diameter is greater than 6mm, which can meet the high eye point requirement of the gun sighting eyepiece.

[0022] Fourth, the whole system only uses 4 pieces of lens, simple structure, easy to do structure mirror tube.

[0023] The double-pupil eyepiece optical system, by setting the jack, the through slot, the insertion rod, the insertion block, the clamping rod, the clamping groove, the fixing bolt and the positioning hole, when the distance of the eyepiece barrel needs to be adjusted, the insertion rod is separated from the inside of the jack, then the eyepiece frame is moved in the inside of the mirror seat, so that the eyepiece frame is moved to the appropriate position, then the insertion rod is inserted into the inside of the jack, at the same time, the two clamping rods are clamped in the corresponding clamping grooves, so that the eyepiece frame is stably clamped in the inside of the mirror seat, at the same time, the fixing bolt can be separated from the corresponding positioning hole by rotating the fixing bolt, then the eyepiece barrel is adjusted to the appropriate position in the inside of the eyepiece frame, then the fixing bolt is clamped in the corresponding positioning hole, the locking effect is more convenient and better in stability, the position of the eyepiece barrel in the inside of the eyepiece frame and the position of the eyepiece frame in the inside of the mirror seat can be conveniently adjusted, at the same time, the mirror seat, the eyepiece frame and the eyepiece barrel can be conveniently disassembled and replaced and repaired, the diopter can be adjusted, the overall structure is simple, and the assembly, disassembly and adjustment operation are more convenient. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structure schematic view of the eyepiece optical system in the application.

[0025] Figure 2 It is an MTF curve diagram of the eyepiece exit pupil distance 20mm in the double-pupil eyepiece optical system of the application.

[0026] Figure 3 It is an MTF curve diagram of the eyepiece exit pupil distance 40mm in the double-pupil eyepiece optical system of the application.

[0027] Figure 4 It is a distortion curve diagram of the double-pupil eyepiece optical system of the application.

[0028] Figure 5 It is a structure schematic view of the mirror seat in the application.

[0029] Figure 6 It is a structure schematic view of the jack in the application. Figure 5

[0030] Figure 7 It is a structure schematic view of the jack in the application. Figure 5

[0031] Figure 8 It is a structure schematic view of the jack in the application.

[0032] ​​The components are: 1. First entrance pupil; 2. Second entrance pupil; 3. First lens; 4. Second lens; 5. Third lens; 6. Micro-display screen; 7. Lens mount; 8. Eyepiece frame; 9. Eyepiece tube; 10. Insertion hole; 11. Through slot; 12. Insert rod; 13. Insert block; 14. Locking rod; 15. Locking groove; 16. Fixing bolt; 17. Positioning hole. Detailed Implementation

[0033] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0035] In one embodiment, such as Figures 1-4 As shown, a dual exit pupil eyepiece optical system has a focal length of 27mm, a magnification of 9.25X, a total optical length of 29mm, and a weight of only 12g; it includes an aperture, a first lens 3, a second lens 4, a third lens 5, and a microdisplay 6 arranged sequentially along the optical axis from the eye toward the microdisplay 6; the first lens 3 is a convex-concave cemented positive lens, the second lens 4 is a biconcave plastic aspherical negative lens, and the third lens 5 is a biconvex glass positive lens;

[0036] The ratio of the focal length of the first lens 3 to the focal length of the entire lens satisfies the following relationship:

[0037] 0.3 < |f1 / f| < 1

[0038] Where f is the focal length of the entire lens, and f1 is the focal length of the first lens, which is 20.7mm;

[0039] The first lens 3 uses a glass lens, which improves the environmental adaptability of the eyepiece;

[0040] A second entrance pupil 2 is provided on the other side of the first lens 3, and a first entrance pupil 1 is provided on the other side of the second entrance pupil 2;

[0041] The center thickness of the cemented positive lens is 6.1 mm for the biconvex lens and 1.1 mm for the biconcave lens; the materials of the cemented positive lens are heavy flint glass and heavy lanthanum flint glass, respectively.

[0042] The central thickness of the plastic aspheric negative lens is 2.2 mm; the material of the plastic aspheric negative lens is PMMA, E48R, K26R, F52R, APL5014DP, PAL5514ML, ep5000, etc., which have excellent optical performance and the density is generally not greater than 1.25 g / cm3, obviously smaller than the density of glass, so that the weight of the ocular optical system is significantly reduced, and the batch molding cost is much lower than that of glass lenses;

[0043] The aspheric coefficients of the plastic aspheric negative lens are A=-1.2292151E-5, B=2.7596927-10, C=-3.2466247E-11, and D=7.7502617E-14.

[0044] The diameters of the first entrance pupil 1 and the second entrance pupil 2 are both between 7.5 mm and 9.5 mm.

[0045] As shown in Figures 2-3 , the abscissa represents the spatial frequency of line pairs per millimeter, and the ordinate represents the MTF value. Figure 2 It can be seen that the embodiment exhibits better contrast within the spatial frequency of 30 lp / mm in the central region, meeting the requirements of human eye observation.

[0046] As shown in Figure 4 , the maximum distortion is only 2.2%.

[0047] The 4 lenses of the double-exit-pupil ocular optical system of the application have a total of 7 surfaces, and the curvature radius, lens center thickness, lens center distance, and lens refractive index meet the following conditions:

[0048] Surface No. Surface Type R (radius of curvature) D (center distance) Nd (refractive index) 1 Stop Infinite 40（20） 2 Spherical 14.37 6.1 1.88 3 Spherical -38.04 1.1 1.96 4 Spherical 59.05 6.44 5 Aspherical -23.11 2.2 1.54 6 Aspherical 9.84 1.23 7 Spherical 12.39 3.3 1.65 8 Spherical -137.17 8.7 9 Spherical Infinite

[0049] The surfaces with surface numbers 5 and 6 in the table are aspheric surfaces, and the aspheric lenses meet the following formula:

[0050]

[0051] Wherein, c=1 / R, R is the vertex radius of the aspheric surface, and k is the quadratic surface parameter. In the embodiment, the aspheric surface type parameters are shown in the following table:

[0052] Surface No. k (quadratic surface constant) A (4th order coefficient) B (6th order coefficient) C (8th order coefficient) 5 4.12 0 0 0 6 0.366 0.000187 0 0

[0053] It should be noted that the two surfaces of the plastic lens can be aspheric surfaces, and appropriate adjustments can be made according to the parameters of the system, the material of the plastic lens, and the difficulty of processing.

[0054] In summary, the double-exit-pupil ocular optical system provided by the application has the following beneficial effects:

[0055] First, the first lens is made of glass, which improves the eyepiece's environmental adaptability.

[0056] Secondly, the second lens uses a plastic lens, which improves the image quality of the eyepiece and reduces the overall weight of the eyepiece. The mass production molding cost is far lower than that of glass lenses.

[0057] Third, the eyepiece of the present invention has two exit pupil distances. The first exit pupil distance is greater than 20mm and the exit pupil diameter is greater than 12mm, which can be used as a front-mounted aiming eyepiece. The second exit pupil distance is greater than 40mm and the exit pupil diameter is greater than 6mm, which can meet the high eyepoint requirements of a gun aiming eyepiece.

[0058] Fourth, the entire system uses only 4 lenses, and its structure is simple and easy to construct.

[0059] like Figures 5-8 As shown, the optical system is located inside the eyepiece tube 9. An eyepiece frame 8 is located on the outside of the eyepiece tube 9, and a lens mount 7 is located on the outside of the eyepiece frame 8. An insertion hole 10 is provided on the outer wall of one end of the eyepiece frame 8. A through groove 11 is provided on the lens mount 7, and an insertion rod 12 is located inside the through groove 11. One end of the insertion rod 12 is located inside the insertion hole 10, and the other end of the insertion rod 12 passes through the through groove 11 and is connected to an insertion block 13. The insertion rod 12 and the insertion hole 10 are used in conjunction. Two sets of locking levers 14 are provided on the outer wall of the insertion rod 12, and the outer wall of the lens mount 7 is provided with… Multiple sets of slots 15 are provided, and the multiple sets of slots 15 are equally spaced on the outer wall of the lens base 7. The locking rods 14 are used in conjunction with the slots 15. When it is necessary to adjust the distance of the eyepiece tube 9, the insertion rod 12 is disengaged from the inside of the insertion hole 10, and then the eyepiece frame 8 is moved inside the lens base 7 so that the eyepiece frame 8 is moved to the appropriate position. Then the insertion rod 12 is inserted into the inside of the insertion hole 10, and at the same time, the two sets of locking rods 14 are locked into the corresponding slots 15, so that the eyepiece frame 8 is stably locked into the inside of the lens base 7.

[0060] like Figures 7-8 As shown, a fixing bolt 16 is provided at the other end of the eyepiece frame 8, and a positioning hole 17 is provided on the outer wall of the eyepiece tube 9. Multiple sets of positioning holes 17 are equally spaced on the outer wall of the eyepiece tube 9. Each set of positioning holes 17 has an internal thread on its inner wall, which is used to cooperate with the thread on the fixing bolt 16. At the same time, by rotating the fixing bolt 16, the fixing bolt 16 can be disengaged from the corresponding positioning hole 17, and the eyepiece tube 9 can be adjusted to a suitable position inside the eyepiece frame 8. Then, the fixing bolt 16 is engaged inside the corresponding positioning hole 17, which achieves a more convenient and stable locking effect. It also facilitates the disassembly of the lens base 7, eyepiece frame 8, and eyepiece tube 9, and makes it convenient to replace and repair the lens base 7, eyepiece frame 8, and eyepiece tube 9, and adjust the diopter. The overall structure is simple, and the assembly, disassembly, and adjustment operations are all convenient.

[0061] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent substitutions or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A dual eye relief eyepiece optical system characterized by, The optical system is composed of a first lens (3), a second lens (4), a third lens (5) and a micro display screen (6) in sequence along the optical axis from the eye to the micro display screen (6); the first lens (3) is a cemented positive lens, and is composed of a biconvex positive lens and a biconcave negative lens in sequence from the eye to the micro display screen (6), the second lens (4) is a biconcave plastic aspheric negative lens, and the third lens (5) is a biconvex glass positive lens; The ratio of the focal length of the first lens (3) to the focal length of the entire lens satisfies the following relationship: 0.3 < |f1 / f| < 1 Wherein, f is the focal length of the entire lens, and f1 is the focal length of the first lens.

2. The dual eyebox eyepiece optical system of claim 1, wherein, The first lens (3) adopts a glass lens, thereby improving the environmental adaptability of the ocular lens.

3. The dual eyebox eyepiece optical system of claim 1, wherein, The other side of the first lens (3) is provided with a second entrance pupil (2), and the other side of the second entrance pupil (2) is provided with a first entrance pupil (1).

4. The dual eyebox eyepiece optical system of claim 1, wherein, The center thickness of the biconvex lens of the cemented positive lens is 6.1 mm, and the center thickness of the biconcave lens is 1.1 mm; the materials of the cemented positive lens are heavy flint glass and heavy lanthanum flint glass, respectively.

5. The dual eyebox eyepiece optical system of claim 1, wherein, The center thickness of the plastic aspheric negative lens is 2.2 mm; the aspheric coefficients of the plastic aspheric negative lens are A=-1.2292151E-5, B=2.7596927-10, C=-3.2466247E-11 and D=7.7502617E-14.

6. The dual eyebox eyepiece optical system of claim 3, wherein, The diameters of the first entrance pupil (1) and the second entrance pupil (2) are both between 7.5 mm and 9.5 mm.

7. The dual eyebox eyepiece optical system of claim 1, wherein, The optical system is arranged in the inside of an ocular lens barrel (9), the outside of the ocular lens barrel (9) is provided with an ocular lens frame (8), the outside of the ocular lens frame (8) is provided with a lens seat (7), one end of the ocular lens frame (8) is provided with a jack (10), the lens seat (7) is provided with a through slot (11), the inside of the through slot (11) is provided with a plug rod (12), one end of the plug rod (12) is arranged in the inside of the jack (10), the other end of the plug rod (12) passes through the through slot (11) and is connected with a plug block (13), and the plug rod (12) is used in cooperation with the jack (10).

8. A dual eyebox eyepiece optical system according to claim 7, wherein, The outside of the plug rod (12) is provided with two groups of clamping rods (14), the outside of the lens seat (7) is provided with multiple groups of clamping grooves (15), the multiple groups of clamping grooves (15) are arranged equidistantly on the outside of the lens seat (7), and the clamping rods (14) are used in cooperation with the clamping grooves (15).

9. A dual eyebox eyepiece optical system according to claim 8, wherein, The other end of the ocular lens frame (8) is provided with a fixing bolt (16), the outside of the ocular lens barrel (9) is provided with a positioning hole (17), multiple groups of the positioning holes (17) are arranged equidistantly on the outside of the ocular lens barrel (9), and an inner thread is arranged on the inner wall of each of the multiple groups of the positioning holes (17), and the inner thread is used in cooperation with the thread on the fixing bolt (16).

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