Relay lens system and optical observation equipment

Abstract

The invention provides a relay lens system and optical observation equipment. The relay lens system comprises at least one relay lens group; the relay lens group comprises a front lens group and a rear lens group, and the front lens group and the rear lens group are respectively a triplet rod-shaped lens and are symmetrically arranged from an intermediate image according to optical characteristics; the triple-glued rodlike lens comprises a first double-meniscus lens, a second double-meniscus lens and a third double-meniscus lens which are glued in sequence. The focal length f1 of the first double-meniscus lens and the focal length f of the triple-cemented rod-shaped lens meet the requirements, the focal length f2 of the second double-meniscus lens and the focal length f of the triple-cemented rod-shaped lens meet the requirements, and the focal length f3 of the third double-meniscus lens and the focal length f of the triple-cemented rod-shaped lens meet the requirements. According to the invention, the tolerance requirement is low during assembly, installation and adjustment are facilitated, and high-standard image quality transmission can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical technology, in particular to a relay lens system and an optical observation device. BACKGROUND

[0002] An endoscope is a device for checking and treating internal tissues of a human body through a head probe and an optical lens. Its working principle is based on optical imaging and probe technology. By introducing a light source and a lens into a body cavity or tissue, microscopic structures or diseased tissues in the body can be observed. The optical imaging of the endoscope is mainly realized by the optical system arranged inside the endoscope. The optical system is composed of an objective lens, a relay lens and a magnifying lens arranged in sequence from the front end (the end of the biological tissue) to the rear end.

[0003] The relay lens is located behind the objective lens and is responsible for transmitting the real image formed by the objective lens to the rear end of the endoscope without loss. Therefore, the image transmission performance of the relay lens has a great influence on the final imaging quality of the optical observation device such as the endoscope. Most of the existing relay lenses are finite conjugate systems, which can image alone, and the object distance and image distance are both finite values. Therefore, the finite conjugate relay lens (i.e. the relay lens of the finite conjugate system) needs to image multiple times within the finite object image distance, resulting in the gradual superposition of aberrations such as spherical aberration, coma, field curvature, etc. In addition, during adjustment, the requirement for the alignment of the image plane of the objective lens and the object plane of the relay lens is high, and optical tilt and translation are easily caused in the actual manufacturing process, which affects the imaging quality.

[0004] Therefore, it is necessary to improve the relay lens in the prior art to solve the above problems.

[0005] It should be noted that the above introduction to the background technology is only for the convenience of clearly and completely describing the technical solutions of the present application, and for the convenience of understanding by those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art only because they are described in the background section of the present application. SUMMARY

[0006] The present application aims at the fact that the existing relay lens needs to image multiple times within the finite object image distance, resulting in the gradual superposition of aberrations such as spherical aberration, coma, field curvature, etc. In addition, during adjustment, the requirement for the alignment of the image plane of the objective lens and the object plane of the relay lens is high, and optical tilt and translation are easily caused in the actual manufacturing process, which affects the imaging quality.

[0007] To achieve the above-mentioned purpose, the present application provides a relay lens system for receiving and transmitting parallel light beams from an objective lens system, the relay lens system comprising: at least one set of relay lens groups; The relay lens group comprises a front lens group and a rear lens group, an intermediate image is formed between the front lens group and the rear lens group, and the front lens group and the rear lens group are both three cemented rod lenses and are arranged in optical property symmetry from the intermediate image; The three cemented rod lenses comprise a first double-crescent lens with negative focal power, a second double-crescent lens with positive focal power, and a third double-crescent lens with positive focal power, a concave surface of the first double-crescent lens and a convex surface of the second double-crescent lens are cemented to form a first cemented surface, a concave surface of the second double-crescent lens and a convex surface of the third double-crescent lens are cemented to form a second cemented surface, and the second cemented surface is located between the first cemented surface and the intermediate image; Wherein, a focal length f1 of the first double-crescent lens and a focal length f of the three cemented rod lenses satisfy A focal length f2 of the second double-crescent lens and the focal length f of the three cemented rod lenses satisfy A focal length f3 of the third double-crescent lens and the focal length f of the three cemented rod lenses satisfy .

[0008] As a further improvement of the present application, a central thickness h1 of the first double-crescent lens, a central thickness h2 of the second double-crescent lens, a central thickness h3 of the third double-crescent lens, and the focal length f of the three cemented rod lenses satisfy .

[0009] As a further improvement of the present application, the focal length f1 of the first double-crescent lens, an Abbe number v1 of the first double-crescent lens, the focal length f2 of the second double-crescent lens, an Abbe number v2 of the second double-crescent lens, the focal length f3 of the third double-crescent lens, and an Abbe number v3 of the third double-crescent lens satisfy .

[0010] As a further improvement of the present application, a pupil diameter D2 of the relay lens group and an effective clear aperture CA2 of the relay lens group satisfy .

[0011] As a further improvement of the present application, a corresponding radius of curvature r1 of a surface of the first double-crescent lens away from the intermediate image, a corresponding radius of curvature r2 of a surface of the first double-crescent lens close to the intermediate image, and a central thickness h1 of the first double-crescent lens satisfy .

[0012] As a further improvement of the present application, a refractive index n1 of the first double-crescent lens and a refractive index n2 of the second double-crescent lens satisfy A refractive index n2 of the second double-crescent lens and a refractive index n3 of the third double-crescent lens satisfy .

[0013] As a further improvement of the present application, the curvature radius r2 corresponding to the first cemented surface and the curvature radius r3 corresponding to the second cemented surface satisfy .

[0014] As a further improvement of the present application, the light flux of the relay lens system is greater than or equal to the light flux of the objective lens system, the wavelength of the relay lens system is equal to the wavelength of the objective lens system, the entrance pupil diameter of the relay lens system is greater than or equal to the exit pupil diameter of the objective lens system, and the field angle of the relay lens system is equal to the field angle of the objective lens system.

[0015] Based on the same design idea, the present application further discloses an optical observation device, comprising: an objective lens system and a relay lens system as described in any one of the above-mentioned inventions, which are arranged in sequence along the same optical axis from the object side.

[0016] As a further improvement of the present application, the optical observation device further comprises: a magnifying lens system arranged on the image side of the relay lens system.

[0017] Compared with the prior art, the present application has the following beneficial effects: The relay lens system comprises: at least one relay lens group, the relay lens group comprising: a front lens group and a rear lens group. An intermediate image is formed between the front lens group and the rear lens group, and the front lens group and the rear lens group are both three-cemented rod lenses and are arranged symmetrically in optical properties from the intermediate image. The three-cemented rod lens comprises: a first double-crescent lens with negative optical power, a second double-crescent lens with positive optical power, and a third double-crescent lens with positive optical power. The concave surface of the first double-crescent lens and the convex surface of the second double-crescent lens are cemented to form a first cemented surface, the concave surface of the second double-crescent lens and the convex surface of the third double-crescent lens are cemented to form a second cemented surface, and the second cemented surface is formed between the first cemented surface and the intermediate image. Wherein, the focal length f1 of the first double-crescent lens and the focal length f of the three-cemented rod lens satisfy , the focal length f2 of the second double-crescent lens and the focal length f of the three-cemented rod lens satisfy , and the focal length f3 of the third double-crescent lens and the focal length f of the three-cemented rod lens satisfy The front lens group in the relay lens group is a lens structure with negative, positive, and positive refractive powers from the object side to the image side, and the rear lens group is a lens structure with positive, positive, and negative refractive powers from the object side to the image side. The focal length of a single lens in the three-cemented rod lens and the overall focal length are limited. The focal length of the first double-crescent lens in the three-cemented rod lens functions in aberration compensation and telecentricity control. The combined focal length of the second double-crescent lens and the third double-crescent lens functions in basic light deflection. Therefore, the relay lens system can realize lossless transmission of the pupil under the premise of low tolerance requirement and better assembly and adjustment, that is, the exit pupil plane of the objective lens system is accurately and correctly transmitted to the subsequent optical system (such as a magnifying lens system or an eyepiece system) through the relay lens system, high-standard image quality transmission is ensured, and the number of lenses is less than that of the prior art, and the cost performance is higher. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A cross-sectional structure of a relay lens system in an embodiment; Figure 2 A cross-sectional structure of a relay lens system in another embodiment; Figure 3 A cross-sectional structure of a relay lens system in still another embodiment; Figure 4 A cross-sectional structure of a relay lens system in still another embodiment; Figure 1 An MTF curve diagram of the relay lens system shown in FIG. 1 under a 0.707 field of view; Figure 5 An MTF curve diagram of the relay lens system shown in FIG. 1 under an edge field of view; Figure 1 An MTF curve diagram of the relay lens system shown in FIG. 1 under a central field of view; Figure 6 Figure 1 An MTF curve diagram of the relay lens system shown in FIG. 2 under a 0.707 field of view; Figure 7 An MTF curve diagram of the relay lens system shown in FIG. 2 under an edge field of view; Figure 2 An MTF curve diagram of the relay lens system shown in FIG. 2 under a central field of view; Figure 8 Figure 2 An MTF curve diagram of the relay lens system shown in FIG. 3 under a 0.707 field of view; Figure 9 An MTF curve diagram of the relay lens system shown in FIG. 3 under an edge field of view; Figure 2 An MTF curve diagram of the relay lens system shown in FIG. 3 under a central field of view; Figure 10 Figure 3 An MTF curve diagram of the relay lens system shown in FIG. 4 under a 0.707 field of view; Figure 11 An MTF curve diagram of the relay lens system shown in FIG. 4 under an edge field of view; Figure 3 An MTF curve diagram of the relay lens system shown in FIG. 4 under a central field of view; Figure 12 Figure 3 ​​​​The MTF curve of the relay lens system in the central field of view is shown. DETAILED DESCRIPTION

[0019] The present application will be described in detail below with reference to the embodiments shown in the drawings, but it should be noted that these embodiments are not limiting to the present application, and equivalent transformations or substitutions of functions, methods, or structures made by those skilled in the art based on these embodiments are within the scope of the present application.

[0020] It should be noted that in the present application, the "object side" refers to the side of the relay lens system 20 close to the entrance pupil plane, i.e., the side of the relay lens system 20 through which light enters from the objective lens system (not shown); the "image side" refers to the side of the relay lens system 20 close to the exit pupil plane, i.e., the side of the relay lens system 20 through which light exits.

[0021] The specific embodiments of the present application will be described in detail below with reference to the drawings. Figure 1 The relay lens system 20a containing the optical axis 25a under the first lens structure of the present application is shown, Figure 2 The relay lens system 20b containing the optical axis 25b under the second lens structure of the present application is shown, Figure 3 The relay lens system 20c containing the optical axis 25c under the third lens structure of the present application is shown.

[0022] Please refer to Figures 1 to 12 As shown, the present application shows a specific embodiment of a relay lens system 20. The relay lens system 20 can be specifically installed in an optical observation device (not shown) used for observing an observation object (such as living or ex vivo biological tissue), which can be, for example, an endoscope. The relay lens system 20 is arranged on the side of the objective lens system away from the observation object, and specifically works in an infinite conjugate distance optical path, for receiving and transmitting parallel light beams from the objective lens system, and emitting parallel light beams, so as to achieve lossless relay transmission of the pupil and optical information between the objective lens system and the magnifying lens system.

[0023] Specifically, the relay mirror system 20 comprises at least one set of relay mirror groups 21, the relay mirror groups 21 comprising a front mirror group 22 and a rear mirror group 24. An intermediate image 23 is formed between the front mirror group 22 and the rear mirror group 24, and the front mirror group 22 and the rear mirror group 24 are both three-cemented rod lenses and are arranged in optical property symmetry from the intermediate image 23. The three-cemented rod lens comprises a first double-curved moon lens 201 with negative focal power, a second double-curved moon lens 202 with positive focal power, and a third double-curved moon lens 203 with positive focal power. The concave surface of the first double-curved moon lens 201 and the convex surface of the second double-curved moon lens 202 are cemented to form a first cemented surface 204, the concave surface of the second double-curved moon lens 202 and the convex surface of the third double-curved moon lens 203 are cemented to form a second cemented surface 205, and the second cemented surface 205 is formed between the first cemented surface 204 and the intermediate image 23.

[0024] wherein the focal length f1 of the first double-curved moon lens 201 and the focal length f of the three-cemented rod lens satisfy , the focal length f2 of the second double-curved moon lens 202 and the focal length f of the three-cemented rod lens satisfy , and the focal length f3 of the third double-curved moon lens 203 and the focal length f of the three-cemented rod lens satisfy .

[0025] More specifically, the front mirror group 22 and the rear mirror group 24 are both three-cemented rod lenses, and the front mirror group 22 and the rear mirror group 24 are arranged in optical property symmetry from the intermediate image 23, and the second cemented surface 205 is located between the first cemented surface 204 and the intermediate image 23. The front mirror group 22 comprises, from the object side to the same optical axis in sequence, the first double-curved moon lens 201, the second double-curved moon lens 202, and the third double-curved moon lens 203. The rear mirror group 24 comprises, from the object side to the same optical axis in sequence, the third double-curved moon lens 203, the second double-curved moon lens 202, and the first double-curved moon lens 201. The concave surface of the first double-curved moon lens 201 and the convex surface of the second double-curved moon lens 202 are cemented to form the first cemented surface 204, and the concave surface of the second double-curved moon lens 202 and the convex surface of the third double-curved moon lens 203 are cemented to form the second cemented surface 205.

[0026] It should be noted that in the front mirror group 22, the object side surface of the first double-curved moon lens 201 is convex, the image side surface is concave, the object side surface of the second double-curved moon lens 202 is convex, the image side surface is concave, and the object side surface of the third double-curved moon lens 203 is convex, the image side surface is concave. In the rear mirror group 24, the object side surface of the third double-curved moon lens 203 is concave, the image side surface is convex, the object side surface of the second double-curved moon lens 202 is concave, the image side surface is convex, and the object side surface of the first double-curved moon lens 201 is concave, the image side surface is convex. In this way, the front mirror group 22 and the rear mirror group 24 are arranged in optical property symmetry from the intermediate image 23.

[0027] In the present application, the front lens group 22 in the relay lens group 21 is a lens structure with negative, positive, and positive refractive powers from the object side to the image side, the rear lens group 24 is a lens structure with positive, positive, and negative refractive powers from the object side to the image side, and the focal length of a single lens and the overall focal length of the three-cemented rod lens are limited. The focal length of the first double-crescent lens 201 in the three-cemented rod lens serves to compensate for aberration and control the telecentricity, and the combined focal length of the second double-crescent lens 202 and the third double-crescent lens 203 serves to deflect the basic light rays. Thus, the relay lens system 20 disclosed in the present application has low tolerance requirements between itself and other optical systems used in combination, and can achieve lossless transmission of the pupil under the premise of low tolerance requirements and better adjustment, that is, the exit pupil plane of the objective lens system is accurately and correctly transmitted to the subsequent optical system (such as a magnifying lens system or an eyepiece system) through the relay lens system 20, ensuring high-standard image quality transmission, and compared with the prior art, the number of lenses is smaller and the cost performance is higher.

[0028] It should be noted that the tolerance of the present application itself includes the manufacturing tolerance between each lens and the assembly tolerance of each lens included in the present application. The aforementioned optical system refers to the objective lens system (not shown) located on the object side of the relay lens system 20 and the magnifying lens system (not shown) located on the image side of the relay lens system 20 in the optical observation device. Since the objective lens system and the magnifying lens system are not the points of the present application, they are not specifically shown in the present application.

[0029] As for the specific number of the relay lens group 21 in the relay lens system 20, the relay lens system 20 includes at least one relay lens group 21, that is, one, two, or more relay lens groups 21. If multiple relay lens groups 21 are included, the multiple relay lens groups 21 are arranged in sequence along the optical axis. The present embodiment does not make more specific limitations on the number of relay lens groups 21, and one relay lens group 21 is exemplarily described in the following embodiments, but this cannot limit the protection scope of the present application.

[0030] In an embodiment, the central thickness h1 of the first double-crescent lens 201, the central thickness h2 of the second double-crescent lens 202, the central thickness h3 of the third double-crescent lens 203, and the focal length f of the three-cemented rod lens satisfy The total length and focal length of the three-cemented rod lens are limited to ensure the stability of the three-cemented rod lens while making the overall relay lens group 21 structure more compact and stable in parameters, facilitating processing.

[0031] In an embodiment, the focal length f1 of the first double-crescent lens 201, the Abbe number v1 of the first double-crescent lens 201, the focal length f2 of the second double-crescent lens 202, the Abbe number v2 of the second double-crescent lens 202, the focal length f3 of the third double-crescent lens 203, and the Abbe number v3 of the third double-crescent lens 203 satisfy The material and focal length of the three double-crescent lenses are limited to eliminate chromatic aberration.

[0032] In an embodiment, the pupil diameter D2 of the relay lens group 21 and the effective clear aperture CA2 of the relay lens group 21 satisfy Thus, it is ensured that all the light rays of all the fields of view can pass through the relay lens group 21, realizing uniform illumination of the full field of view without vignetting, and reserving a safety margin for the processing error and assembly error of the lenses contained in the relay lens group 21, to ensure that the optical performance requirements can be stably met under actual manufacturing conditions.

[0033] In an embodiment, the corresponding curvature radius r1 of the side of the first double-crescent lens 201 away from the intermediate image 23, the corresponding curvature radius r2 of the side of the first double-crescent lens 201 close to the intermediate image 23, and the central thickness h1 of the first double-crescent lens 201 satisfy Thus, the first double-crescent lens 201 is facilitated to be processed.

[0034] In an embodiment, by limiting the material of the three double-crescent lenses, the refractive index n1 of the first double-crescent lens 201 and the refractive index n2 of the second double-crescent lens 202 satisfy Thus, the higher-order spherical aberration and coma are controlled, and it is ensured that the curvature radius of the first cemented surface 204 is not too small to be difficult to process; the refractive index n2 of the second double-crescent lens 202 and the refractive index n3 of the third double-crescent lens 203 satisfy Thus, chromatic aberration is corrected, and the correction of the flat image field is facilitated.

[0035] In an embodiment, the corresponding curvature radius r2 of the first cemented surface 204 and the corresponding curvature radius r3 of the second cemented surface 205 satisfy Thus, by controlling the shape of the three-cemented rod lens, the three-cemented rod lens is facilitated to be processed, and the manufacturing cost and difficulty are reduced.

[0036] In an embodiment, the light flux of the relay lens system 20 is greater than or equal to the light flux of the objective lens system, the wavelength of the relay lens system 20 is equal to the wavelength of the objective lens system, the entrance pupil diameter of the relay lens system 20 is greater than or equal to the exit pupil diameter of the objective lens system, and the field of view angle of the relay lens system 20 is equal to the field of view angle of the objective lens system, to transfer the optical information of the object captured by the objective lens system to the rear end of the optical observation equipment, realizing lossless connection between the exit pupil of the objective lens system and the entrance pupil of the relay lens system 20, and ensuring efficient and vignetting-free transmission of the light flux.

[0037] Based on the same design idea, the present application also discloses an optical observation equipment (not shown), which comprises an objective lens system and the relay lens system 20 disclosed above arranged in sequence on the same optical axis from the object side, and specific details are as described above, which will not be repeated here.

[0038] In one embodiment, the optical observation device further includes a magnifying glass system (not shown) disposed on the image side of the relay mirror system 20, the magnifying glass system being used to receive the parallel light beam from the relay mirror system 20 and convert the parallel light into a real image of the object to be measured.

[0039] Preferably, the objective lens system and the magnifying lens system are both infinitely conjugate, so each optical system is designed independently and corrects its own aberrations independently. Finally, they are combined to achieve the target function. Thus, under the premise of the same light flux, different optical functions can be achieved by changing the optical system, such as adapting to different CMOS cameras, different object-side fields of view, etc.

[0040] The following describes a numerical embodiment of the relay mirror system 20 of this application.

[0041] [Example 1] like Figure 1 As shown, a front lens group 22a is formed by cementing a first double meniscus lens 201a, a second double meniscus lens 202a, and a third double meniscus lens 203a sequentially from the object side. A rear lens group 24a is formed by cementing the third double meniscus lens 203a, the second double meniscus lens 202a, and the first double meniscus lens 201a sequentially from the object side. The front lens group 22a and the rear lens group 24a are arranged sequentially from the object side to form a relay lens group 21a. Simultaneously, in the relay lens group 21a, the concave surface of the first double meniscus lens 201a and the convex surface of the second double meniscus lens 202a are cemented together to form a first cemented surface 204a, and the concave surface of the second double meniscus lens 202a and the convex surface of the third double meniscus lens 203a are cemented together to form a second cemented surface 205a.

[0042] Table 1 shows the basic parameters of the relay mirror system 20a of Embodiment 1, including the incident pupil plane and the intermediate image 23a, including the serial number, radius of curvature, center thickness, refractive index and Abbe number.

[0043] In the basic parameter table, number 1 corresponds to the incident pupil plane, numbers 2 to 5 correspond to the planes closest to the object side to the planes closest to the image side in the front lens group 22a, number 6 corresponds to the intermediate image 23a, and numbers 7 to 10 correspond to the planes closest to the object side to the planes closest to the image side in the rear lens group 24a.

[0044] The "Radius of Curvature" column indicates the radius of curvature corresponding to the surface with the current serial number. The sign of the radius of curvature is positive if the surface bulges towards the object side and negative if it bulges towards the image side.

[0045] The center thickness column indicates the distance between the center positions of the current numbered face and the next numbered face.

[0046] The refractive index column represents the refractive index of each lens under light with a wavelength of 546 nm, and it is filled in the serial number corresponding to the object-side surface of the lens.

[0047] The Abbe number column represents the Abbe number corresponding to the material of each lens, and it is filled in the serial number corresponding to the object-side surface of the lens.

[0048] The focal length of the relay lens system 20a shown in Example 1 is 20.25 (unit: millimeter, mm), the entrance pupil diameter is 3.20 (unit: millimeter, mm), the effective clear aperture is 3.2 (unit: millimeter, mm), and the half field angle is 4.3 (unit: degree, °). The length unit of the values in Table 1 is "millimeter" (abbreviation "mm"), but it is only one column and can be scaled up or down proportionally, so other appropriate units can also be used. At the same time, the values shown in Table 1 are rounded to the specified number of digits.

[0049]

[0050] Table 2 shows the calculated values of the relay lens system 20a shown in Example 1.

[0051]

[0052] See Figures 4 to 6 The MTF curves of Example 1 are respectively shown at 0.707 field of view, edge field of view, and central field of view, and Figures 4 to 6 the MTF curve in the ideal case is also shown for comparison. In Figures 4 to 6 it, the black solid line (Diff.Limit-Tangential) and the black dashed line (Diff. Limit-Sagittal) respectively refer to the MTF curves of the relay lens system 20a in the meridional direction and the sagittal direction under ideal conditions. And the MTF curves in the meridional direction and the sagittal direction coincide under ideal conditions. Therefore, Figures 4 to 6The black solid lines and black dashed lines in the diagram overlap, and only the black solid lines are shown. The green solid line (3.0406 (deg) - Tangential) and the green dashed line (3.0406 (deg) - Sagittal) refer to the MTF curves of the relay system 20a in the meridional and sagittal directions under a 0.707 field of view, respectively; the red solid line (4.3000 (deg) - Tangential) and the red dashed line (4.3000 (deg) - Sagittal) refer to the MTF curves of the relay system 20a in the meridional and sagittal directions under a peripheral field of view, respectively; the blue solid line (0.0000 (deg) - Tangential) and the blue dashed line (0.0000 (deg) - Sagittal) refer to the MTF curves of the relay system 20a in the meridional and sagittal directions under a central field of view, respectively. Since the blue solid lines and blue dashed lines overlap, only the blue solid lines are shown.

[0053] Unless otherwise specified, the above-described methods of illustrating the relay mirror system 20a of Embodiment 1, the symbols, meanings, and recording methods of various data are also applicable to the relay mirror systems 20b and 20c of Embodiments 2 and 3 below, so repeated descriptions are omitted below.

[0054] [Example 2] like Figure 2 As shown, a front lens group 22b is formed by cementing a first double meniscus lens 201b, a second double meniscus lens 202b, and a third double meniscus lens 203b sequentially from the object side. A rear lens group 24b is formed by cementing a third double meniscus lens 203b, a second double meniscus lens 202b, and a first double meniscus lens 201b sequentially from the object side. The front lens group 22b and the rear lens group 24b are arranged sequentially from the object side to form a relay lens group 21b. Simultaneously, the concave surface of the first double meniscus lens 201b and the convex surface of the second double meniscus lens 202b in the first relay lens group 21b are cemented together to form a first cemented surface 204b, and the concave surface of the second double meniscus lens 202b and the convex surface of the third double meniscus lens 203b are cemented together to form a second cemented surface 205b.

[0055] Table 3 shows the basic parameters of the lens surfaces included in the relay mirror system 20b of Embodiment 2, including the incident pupil surface and the intermediate image 23b, which include the serial number, radius of curvature, center thickness, refractive index, and Abbe number.

[0056] The relay lens system 20b shown in Example 2 has a focal length of 19.6 mm, an entrance pupil diameter of 3.2 mm, an effective aperture of 3.2 mm, and a half field of view of 4.3 degrees.

[0057]

[0058] The calculated values of the relay mirror system 20b shown in Example 2 are shown in Table 4.

[0059]

[0060] Refer Figures 7 to 9 The MTF curves of Example 2 shown respectively at a 0.707 field of view, an edge field of view, and a central field of view, and Figures 7 to 9 also show the MTF curve under ideal conditions for comparison. In Figures 7 to 9 it, the solid black line (Diff.Limit-Tangential) and the dashed black line (Diff. Limit-Sagittal) respectively refer to the MTF curves of the relay mirror system 20b in the meridional direction and the sagittal direction under ideal conditions, and the MTF curves in the meridional direction and the sagittal direction coincide under ideal conditions. Therefore, Figures 7 to 9 the solid black line and the dashed black line included in it coincide with each other, and only the solid black line can be shown. The solid green line (3.0406 (deg)-Tangential) and the dashed green line (3.0406 (deg)-Sagittal) respectively refer to the MTF curves of the relay mirror system 20b in the meridional direction and the sagittal direction at a 0.707 field of view; the solid red line (4.3000 (deg)-Tangential) and the dashed red line (4.3000 (deg)-Sagittal) respectively refer to the MTF curves of the relay mirror system 20b in the meridional direction and the sagittal direction at the edge field of view; the solid blue line (0.0000 (deg)-Tangential) and the dashed blue line (0.0000 (deg)-Sagittal) respectively refer to the MTF curves of the relay mirror system 20b in the meridional direction and the sagittal direction at the central field of view. Since the solid blue line and the dashed blue line overlap, only the solid blue line can be shown.

[0061] [Example 3] As Figure 3 shown, the front lens group 22c is formed by sequentially gluing the first double meniscus lens 201c, the second double meniscus lens 202c, and the third double meniscus lens 203c from the object side, the rear lens group 24c is formed by sequentially gluing the third double meniscus lens 203c, the second double meniscus lens 202c, and the first double meniscus lens 201c from the object side, and the front lens group 22c and the rear lens group 24c are arranged sequentially from the object side to form the relay lens group 21c. At the same time, the concave surface of the first double meniscus lens 201c and the convex surface of the second double meniscus lens 202c in the first relay lens group 21c are glued to form the first glued surface 204c, and the concave surface of the second double meniscus lens 202c and the convex surface of the third double meniscus lens 203c are glued to form the second glued surface 205c.

[0062] Table 5 shows the basic parameter table of the lens surfaces contained in the relay mirror system 20c of Example 3, including the entrance pupil surface and the intermediate image 23c, which includes serial number, radius of curvature, central thickness, refractive index, and Abbe number.

[0063] The focal length of the relay mirror system 20c shown in Example 3 is 18.44 (unit: millimeter, mm), the entrance pupil diameter is 3.2 (unit: millimeter, mm), the effective clear aperture is 3.2 (unit: millimeter, mm), and the half field angle is 4.3 (unit: degree, °).

[0064]

[0065] Table 6 shows the calculated values of the relay mirror system 20c shown in Example 3.

[0066]

[0067] Ref. Figures 10 to 12 The MTF curves of Example 3 are respectively shown at 0.707 field of view, edge field of view, and central field of view, and Figures 10 to 12 also shows the MTF curve under ideal conditions for comparison. In Figures 10 to 12 it, the black solid line (Diff. Limit-Tangential) and the black dashed line (Diff. Limit-Sagittal) respectively refer to the MTF curves of the relay mirror system 20c in the meridional direction and the sagittal direction under ideal conditions, and the MTF curves in the meridional direction and the sagittal direction under ideal conditions coincide. Therefore, Figures 10 to 12 the black solid line and the black dashed line contained in it coincide with each other and only the black solid line can be shown. The green solid line (3.0406 (deg)-Tangential) and the green dashed line (3.0406 (deg)-Sagittal) respectively refer to the MTF curves of the relay mirror system 20c in the meridional direction and the sagittal direction at 0.707 field of view; the red solid line (4.3000 (deg)-Tangential) and the red dashed line (4.3000 (deg)-Sagittal) respectively refer to the MTF curves of the relay mirror system 20c in the meridional direction and the sagittal direction at the edge field of view; the blue solid line (0.0000 (deg)-Tangential) and the blue dashed line (0.0000 (deg)-Sagittal) respectively refer to the MTF curves of the relay mirror system 20c in the meridional direction and the sagittal direction at the central field of view. Since the blue solid line and the blue dashed line overlap, only the blue solid line can be shown.

[0068] In summary, in the ideal case, the MTF curves in the meridional direction and the sagittal direction coincide to achieve the best imaging effect, and the lower the distortion rate is, in the actual test case, the closer the ordinate corresponding to the same abscissa is, which proves that the MTF curves in the meridional direction and the sagittal direction are closer to each other; at the same time, from the actual imaging angle, the closer the ordinate corresponding to the same abscissa in the test case and the ordinate corresponding to the same abscissa in the ideal case is, the better the imaging efficiency is, the image tends to be real, and the lower the distortion rate of the image is. Based on this, from the above, it can be known that the relay mirror system 20 disclosed in the present application can realize lossless transmission of the pupil under the premise of low tolerance requirement and being more conducive to adjustment and installation. Figures 4 to 12 It can be known that the relay mirror system 20 disclosed in the present application can realize lossless transmission of the pupil under the premise of low tolerance requirement and being more conducive to adjustment and installation.

[0069] The series of detailed descriptions listed above are only specific descriptions of the feasible implementation manners of the present application, and are not used to limit the protection scope of the present application, and equivalent implementation manners or changes made without departing from the spirit of the present application should be included in the protection scope of the present application.

[0070] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and the person skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that can be understood by the person skilled in the art.

Claims

1. A relay mirror system for receiving and passing on a parallel light beam from an objective lens system, characterized in that The relay lens system comprises at least one set of relay lens groups; The relay lens groups comprise a front lens group and a rear lens group, an intermediate image is formed between the front lens group and the rear lens group, and the front lens group and the rear lens group are both three cemented rod lenses and are arranged in optical property symmetry from the intermediate image; The three cemented rod lenses comprise a first double-crescent lens with negative optical power, a second double-crescent lens with positive optical power, and a third double-crescent lens with positive optical power, the concave surface of the first double-crescent lens and the convex surface of the second double-crescent lens are cemented to form a first cemented surface, the concave surface of the second double-crescent lens and the convex surface of the third double-crescent lens are cemented to form a second cemented surface, and the second cemented surface is located between the first cemented surface and the intermediate image; Wherein, the focal length f1 of the first double-crescent lens and the focal length f of the three-cemented rod lens satisfy , the focal length f2 of the second double-crescent lens and the focal length f of the three-cemented rod lens satisfy , the focal length f3 of the third double-crescent lens and the focal length f of the three-cemented rod lens satisfy .

2. The relay mirror system of claim 1, wherein, The central thickness h1 of the first double-crescent lens, the central thickness h2 of the second double-crescent lens, the central thickness h3 of the third double-crescent lens, and the focal length f of the triple-cemented rod lens satisfy .

3. The relay mirror system of claim 1, wherein, focal length f1 of the first double-crescent lens, Abbe number v1 of the first double-crescent lens, focal length f2 of the second double-crescent lens, Abbe number v2 of the second double-crescent lens, focal length f3 of the third double-crescent lens, Abbe number v3 of the third double-crescent lens satisfy .

4. The relay mirror system of claim 1, wherein, The pupil diameter D2 of the relay lens group and the effective clear aperture CA2 of the relay lens group satisfy .

5. The relay mirror system of claim 1, wherein, The corresponding curvature radius r1 of the side of the first double-crescent lens far from the intermediate image, the corresponding curvature radius r2 of the side of the first double-crescent lens close to the intermediate image, and the central thickness h1 of the first double-crescent lens satisfy .

6. The relay mirror system of claim 1, wherein, The refractive index n1 of the first double-crescent lens and the refractive index n2 of the second double-crescent lens satisfy The refractive index n2 of the second double-crescent lens and the refractive index n3 of the third double-crescent lens satisfy .

7. The relay mirror system of claim 1, wherein, The curvature radius r2 corresponding to the first gluing surface and the curvature radius r3 corresponding to the second gluing surface satisfy .

8. The relay mirror system of claim 1, wherein, The light flux of the relay lens system is greater than or equal to the light flux of the objective lens system, the wavelength of the relay lens system is equal to the wavelength of the objective lens system, the entrance pupil diameter of the relay lens system is greater than or equal to the exit pupil diameter of the objective lens system, and the field of view angle of the relay lens system is equal to the field of view angle of the objective lens system.

9. An optical viewing device, characterized by Comprise: An objective lens system and the relay lens system according to any one of claims 1 to 8 are arranged in sequence on the optical axis from the object side.

10. The optical viewing device of claim 9, wherein, The optical observation device further comprises a magnifying lens system arranged on the image side of the relay lens system.

Images