Illumination and image rotation light path integrated superfine hard optical fiber endoscope

Abstract

The invention discloses an illumination and image rotation light path integrated superfine hard optical fiber endoscope which is characterized in that an optical fiber image transmission bundle is used for replacing a traditional rodlike lens to serve as a relay system, and an objective lens group, an image rotation system, an inverted image group, an eyepiece group and a cubic beam splitter prism are sequentially arranged in a single-channel steel pipe of the endoscope; a cold light source is connected into a light guide opening through a light guide beam for illumination, illumination light rays are sequentially transmitted to an object plane through a cubic prism and a front optical system, and then imaging is achieved through a follow-up optical system by reflection light rays of the object, so that the illumination and imaging integrated design is completed. Illuminating optical fibers on the periphery of the objective lens are removed, a double-channel steel pipe of the endoscope is replaced with a single-channel steel pipe, the aperture of an optical system of the insertion part ranges from 0.4 mm to 0.8 mm successfully, and the overall mechanical diameter of the insertion part is smaller than 1 mm. The overall diameter of the endoscope is reduced, the relative aperture of the objective lens group is increased, and the resolution of the whole optical system is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of endoscopes, and in particular to an ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths. Background Art

[0002] Ultrafine rigid endoscopes are mainly used in the fields of medical treatment and industrial inspection. In the medical field, they can be used to inspect the narrower parts of the human body's natural cavities, so that doctors can better understand the condition of the diseased tissue; in the field of animal medical experiments, they can also be used for artificial insemination, pregnancy diagnosis, embryo transplantation, etc. in animal husbandry, and their experimental results play an important role in animal medicine and other aspects; in industrial inspection, they can be used to inspect the internal conditions of some small-caliber pipes, such as the tiny pipes inside the engine in the aerospace field, to check whether there is damage or blockage; they are also used to inspect the internal structure of precision instruments and the subtle defects of parts to ensure the quality and performance of the instruments.

[0003] Therefore, designing an ultra-fine endoscope with a small caliber, high resolution, the ability to deeply observe and detect the target area, and easy operation is an urgent problem to be solved. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides an ultra-fine rigid fiber endoscope with integrated illumination and image transfer optical paths, using an optical fiber image transmission bundle to replace the traditional rod lens as a relay system, the objective lens group, image transfer system, inverted image group, eyepiece group, and cubic beam splitter prism are sequentially arranged in the single-channel steel tube of the endoscope, and a cold light source is used to connect to the light guide port through a light guide beam for illumination. After the illumination light is sequentially transmitted to the object surface through the cubic prism and the front optical system, the reflected light of the object is imaged through the subsequent optical system, completing the integrated design of illumination and imaging. The present invention removes the illumination optical fiber outside the objective lens, replaces the double-channel steel tube of the endoscope with a single-channel steel tube, and successfully achieves an insertion part optical system aperture of 0.4 to 0.8 mm, and the overall mechanical diameter of the insertion part is less than 1 mm. The present invention not only reduces the overall diameter of the endoscope, but also increases the relative aperture of the objective lens group, greatly improving the resolution of the entire optical system.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] An ultra-fine rigid fiber endoscope with integrated illumination and image transfer optical paths comprises a housing, a cold light source, an image transfer system, an optical system and a cubic beam splitter prism; the optical system comprises an objective lens group G1, an inverted image group G2 and an eyepiece group G3; the image transfer system comprises an optical fiber image transmission bundle F; the rigid fiber endoscope uses an optical fiber image transmission bundle to replace a traditional rod lens as a relay system, integrating illumination and imaging; the objective lens group G1, the optical fiber image transmission bundle F, the inverted image group G2, the eyepiece group G3 and the cubic beam splitter prism SP are placed in sequence; the cold light source is connected to the light guide port through a light guide beam for illumination, and the illumination light passes through the cubic beam splitter prism SP, the eyepiece group G3, the inverted image group G2, the optical fiber image transmission bundle F and the objective lens group G1 in sequence and then is transferred to an object surface, and the reflected light of the object passes through the objective lens group G1, the optical fiber image transmission bundle F, the inverted image group G2, the eyepiece group G3 and the cubic beam splitter prism SP in sequence and then is received by the image surface to form an image.

[0007] As a preferred embodiment of the above scheme, each lens of the optical system has matching parameters, so that the aperture of the optical system of the insertion part of the endoscope of the present invention is less than 0.4-0.8 mm, and the overall mechanical diameter is less than 1 mm.

[0008] As a preferred embodiment of the above scheme, the objective lens group G1 includes a protective glass P1, a first lens L1, a parallel plate P2, a second lens L2, a third lens L3, and a fourth lens L4 in sequence; the image relay system includes an optical fiber image transmission bundle F; the inverted image group G2 includes a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 in sequence; the eyepiece group G3 includes a ninth lens L9, a tenth lens L10, and an eleventh lens L11 in sequence.

[0009] As a preferred embodiment of the above scheme, the ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths is characterized in that the focal lengths of the first lens L1 to the eleventh lens L11 are f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, f21, f22, f23, f24, f25, f26, f27, f28, f30, f31, f32, f33, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, f21, f22, f33, f4, f5 10 、f 11 The clear apertures of the first lens L1 to the eleventh lens L11 are D1, D2, D3, D4, D5, D6, D7, D8, D9, D 10 , D 11 ; The relationship between the focal length and the aperture of each lens satisfies the following conditions:

[0010] (-0.9~-0.8)≤f1 / D1≤(-0.7~-0.6);

[0011] (2.0~2.1)≤f2 / D2≤(2.2~2.3);

[0012] (0.7~0.8)≤f3 / D3≤(1.0~1.1);

[0013] (-1.9~-1.8)≤f4 / D4≤(-1.7~-1.6);

[0014] (-1.6~-1.5)≤f5 / D5≤(-1.3~-1.2);

[0015] (1.0~1.1)≤f6 / D6≤(1.2~1.3);

[0016] (-1.9~-1.8)≤f7 / D7≤(-1.5~-1.4);

[0017] (1.1~1.2)≤f8 / D8≤(1.3~1.4);

[0018] (2.8~2.9)≤f9 / D9≤(3.0~3.1);

[0019] (3.0~3.1)≤f 10 / D 10 ≤(3.2~3.3);

[0020] (-5.5~-5.4)≤f 11 / D 11 ≤(-5.3~-5.2).

[0021] As a preferred embodiment of the above scheme, in the objective lens group G1, the protective glass P1 has no optical power; the first lens L1 has a negative optical power, (-1.77 to -1.76) ≤ Φ1 ≤ (-1.74 to -1.73); the parallel plate P2 has no optical power; the second lens L2 has a positive optical power, (0.72 to 0.73) ≤ Φ2 ≤ (0.74 to 0.75); the third lens L3 has a positive optical power, 1.60 to 1.61 ≤ Φ3 ≤ 1.62 to 1.63; the fourth lens L4 has a negative optical power, (-0.85 to -0.84) ≤ Φ4 ≤ (-0.83 to -0.82); in the inverted image group G2, the fifth lens L5 The sixth lens L6 has a positive focal power, (1.17-1.16)≤Φ6≤(1.18-1.19); the seventh lens L7 has a negative focal power, (-0.79--0.78)≤Φ7≤(-0.76--0.75); the eighth lens L8 has a positive focal power, (1.15-1.16)≤Φ8≤(1.17-1.18); in the eyepiece group G3, the ninth lens L9 has a positive focal power, (0.44-0.45)≤Φ9≤(0.46-0.47); the tenth lens L10 has a positive focal power, 0.62-0.63≤Φ 10 ≤0.64~0.65; the eleventh lens L11 has negative power, (-0.33~-0.32)≤Φ11 ≤(-0.31~-0.30).

[0022] As a preferred embodiment of the above scheme, in the objective lens group G1, the material refractive index of the protection glass P1 is 1.75≤Nd1≤1.85, and the Abbe number is 70≤Vd1≤80; the material refractive index of the first lens L1 is 1.85≤Nd1≤1.95, and the Abbe number is 30≤Vd1≤40; the material refractive index of the parallel plate P2 is 1.75≤Nd1≤1.85, and the Abbe number is 20≤Vd1≤30; the material refractive index of the second lens L2 is 1.80≤Nd2≤1.90, and the Abbe number is 40≤Vd2≤50; the material refractive index of the third lens L3 is 1.70≤Nd3≤1.80, and the Abbe number is 40≤Vd3≤50; the material refractive index of the fourth lens is 1.75≤Nd4≤1.85, and the Abbe number is is 20≤Vd4≤30; in the inverted image group G2, the material refractive index of the fifth lens L5 is 1.95≤Nd5≤2.05, and the Abbe number is 20≤Vd5≤30; the material refractive index of the sixth lens L6 is 1.70≤Nd6≤1.80, and the Abbe number is 40≤Vd6≤50; the material refractive index of the seventh lens L7 is 1.90≤Nd7≤2.00, and the Abbe number is 20≤Vd7≤30; the material refractive index of the eighth lens L8 is 1.70≤Nd8≤1.80, and the Abbe number is 40≤Vd8≤50; in the eyepiece group G3, the material refractive index of the ninth lens L9 is 1.55≤Nd9≤1.65, and the Abbe number is 60≤Vd9≤70; the material refractive index of the tenth lens L10 is 1.45≤Nd 10 ≤1.55, Abbe number is 40≤Vd 10 ≤50; the refractive index of the material of the eleventh lens L11 is 1.90≤Nd 11 ≤2.00, Abbe number is 20≤Vd 11 ≤30.

[0023] As a preferred embodiment of the above scheme, the distance between the second lens L2 and the third lens L3 is 1.98 mm to 2.02 mm; the aperture is located between the second lens L2 and the third lens L3; the distance between the sixth lens L6 and the seventh lens L7 is 2.98 mm to 3.02 mm; the distance between the eighth lens L8 and the ninth lens L9 is 2.20 mm to 2.24 mm; the distance between the ninth lens L9 and the tenth lens L10 is 2.14 mm to 2.18 mm.

[0024] As a preferred embodiment of the above scheme, the third lens L3 and the fourth lens L4 form a doublet lens, the fifth lens L5 and the sixth lens L6 form a doublet lens, the seventh lens L7 and the eighth lens L8 form a doublet lens, and the tenth lens L10 and the eleventh lens L11 form a doublet lens.

[0025] As a preferred embodiment of the above scheme, the size range of the fiber optic imaging bundle is diameter Φ0.35mm*length L50mm~5000mm; the image acquisition end at the front end and the output end at the rear end of the fiber optic imaging bundle are respectively connected behind the endoscope objective lens group and in front of the inverted image group through coupling optical glue.

[0026] As a preferred embodiment of the above solution, the size of the cubic beam splitter prism ranges from 3mm*3mm to 8mm*8mm; the cubic beam splitter prism is fixed at the connection between the light guide port and the optical system through an endoscope base.

[0027] The present invention has the following beneficial effects:

[0028] The present invention provides an ultra-fine rigid fiber endoscope with integrated illumination and image transfer optical paths, which uses a cold light source instead of an ordinary light source. It has good color reproduction, less heat generation, can achieve long-term light source use, and has excellent imaging function. In addition, its brightness, color temperature and other properties can be flexibly adjusted by an electronic system, which is convenient for operators to adapt to different environments when using it.

[0029] The present invention removes the light-guiding optical fiber portion of the outer layer of the objective lens and replaces the double-channel steel tube with a single-channel steel tube. Compared with the traditional rigid endoscope, the light aperture of the endoscope is increased to a certain extent, and it has the advantages of relatively large aperture and higher resolution.

[0030] The invention makes the mechanical diameter of the insertion part of the endoscope ≤1mm by matching the objective lens group, the image transfer system, the inverted image group, the eyepiece group, the cubic beam splitter prism and the cold light source. The final imaging quality can reach the diffraction limit. It has a simple structure and low cost, and can well meet the current needs of deep hole visualization observation in the medical industry and industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings:

[0032] Figure 1 This is a schematic diagram of the mechanical structure of an ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as described in Example 1 of the present invention;

[0033] Figure 2 This is a light path diagram of an ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer light paths as described in Example 1 of the present invention;

[0034] Figure 3This is a schematic diagram of the optical system composition of an ultra-fine rigid fiber optic endoscope with integrated illumination and image transfer optical paths as described in Example 1 of the present invention;

[0035] Figure 4 The MTF curve diagram of the ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths on the image plane described in Example 1 of the present invention;

[0036] Figure 5 The MTF curve diagram on the image plane of an ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as described in Example 2 of the present invention;

[0037] In the figure:

[0038] 1-housing; 2-cold light source; 3-light guide port; G1-objective lens group; F-fiber image transmission bundle; G2-inverted image group; G3-eyepiece group, SP-cube beam splitter;

[0039] FT-light cone; ILP-illumination optical path; IMP-imaging optical path;

[0040] P1-protective glass; L1-first lens; P2-parallel plate; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens; L8-eighth lens; L9-ninth lens; L10-tenth lens; L11-eleventh lens. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described and illustrated below in conjunction with the drawings in the embodiments of the present invention.

[0042] The present invention is an ultra-fine rigid endoscope system, which can also be called an ultra-fine diameter fiber optic endoscope system. It can be used in the medical field to examine the narrower parts of the human body's natural cavities, so that doctors can better understand the condition of the diseased tissue; in the field of animal medical experiments, it can also be used for artificial insemination, pregnancy diagnosis, embryo transplantation, etc. in animal husbandry; in the industrial field, it can be used to inspect automobile manufacturing, ultra-fine apertures, etc.

[0043] Example 1

[0044] like Figure 1 , Figure 2As shown, this embodiment is an ultra-fine rigid fiber endoscope with integrated illumination and image transfer optical paths, comprising a housing 1, a cold light source 2, a light guide port 3, an image transfer system, an optical system, and a cubic beam splitter SP; the optical system comprises an objective lens group G1, an inverted image group G2, and an eyepiece group G3; the image transfer system comprises an optical fiber image transmission bundle F; this rigid fiber endoscope uses an optical fiber image transmission bundle to replace a traditional rod lens as a relay system, integrating illumination and imaging; the objective lens group G1, the optical fiber image transmission bundle F, the inverted image group G2, the eyepiece group G3 ... The lens group G3 and the cubic beam splitter prism SP are placed in the single-channel steel tube of the endoscope in sequence; the cold light source 2 is connected to the light guide port 3 through the light guide beam for illumination, and the illumination light passes through the cubic beam splitter prism SP, the eyepiece group G3, the inverted image group G2, the optical fiber image transmission bundle F, and the objective lens group G1 in sequence and is transmitted to the object surface; the reflected light of the object passes through the objective lens group G1, the optical fiber image transmission bundle F, the inverted image group G2, the eyepiece group G3 and the cubic beam splitter prism SP in sequence and is received by the image surface to form an image, thereby realizing the integrated design of the illumination optical path and the image transfer optical path.

[0045] Furthermore, if Figure 3 As shown, the objective lens group G1 includes a protective glass P1, a first lens L1, a parallel plate P2, a second lens L2, a third lens L3, and a fourth lens L4 in sequence; the image relay system includes an optical fiber image transmission bundle F; the inverted image group G2 includes a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 in sequence; the eyepiece group G3 includes a ninth lens L9, a tenth lens L10, and an eleventh lens L11 in sequence.

[0046] Specifically, the cold light source 2 is connected to the light guide port 3 for illumination through the light guide beam. The illumination light passes through the cubic beam splitter SP and then passes through the eleventh lens L11, the tenth lens L10, the ninth lens L9 of the eyepiece group G3, the eighth lens L8, the seventh lens L7, the sixth lens L6, the fifth lens L5 of the inverted image group G2, the optical fiber image bundle F, the fourth lens L4, the third lens L3, the second lens L2, the parallel plate P2, the first lens L1, and the protective glass P1 of the objective lens group G1, and finally reaches the object surface. The reflected light of the object passes through the objective lens group G1 and the subsequent optical system in sequence and is received by the image surface to form an image.

[0047] In the ultra-fine rigid fiber optic endoscope with integrated illumination and image transfer optical paths described in this embodiment, each lens has compatible optical parameters, so that the mechanical caliber of the insertion part of the ultra-fine rigid endoscope is less than 1mm, the caliber of the optical system of the insertion part is 0.4-0.8mm, and the working distance is 10mm. The optical parameters include: the type of lens, the focal length of the lens, the radius of curvature of each surface of the lens, the aperture of the lens, the material of the lens, and the working distance and caliber of the ultra-fine rigid endoscope.

[0048] Furthermore, the focal lengths of the lenses (the first lens, the second lens, ..., the eleventh lens) in this embodiment are f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, f21, f22, f23, f24, f25, f26, f 10 、f 11 ; The apertures of each lens are D1, D2, D3, D4, D5, D6, D7, D8, D9, D 10 , D 11 ; The relationship between the focal length and the aperture of each lens satisfies the following conditions:

[0049] -0.9≤f1 / D1≤-0.7;

[0050] 2.1≤f2 / D2≤2.3;

[0051] 0.8≤f3 / D3≤1.0;

[0052] -1.9≤f4 / D4≤-1.7;

[0053] -1.5≤f5 / D5≤-1.3;

[0054] 1.0≤f6 / D6≤1.2;

[0055] -1.8≤f7 / D7≤-1.6;

[0056] 1.2≤f8 / D8≤1.4;

[0057] 2.8≤f9 / D9≤3;

[0058] 3.0≤f 10 / D 10 ≤3.2;

[0059] -5.4≤f 11 / D 11 ≤-5.2;

[0060] As a preferred embodiment of the above scheme, in the objective lens group G1, the protection glass P1 has no optical power; the first lens L1 has negative optical power, -1.76≤Φ1≤-1.74; the parallel plate P2 has no optical power; the second lens L2 has positive optical power, 0.72≤Φ2≤0.74; the third lens L3 has positive optical power, 1.60≤Φ3≤1.62; and the fourth lens L4 has negative optical power, -0.84≤Φ4≤-0.82.

[0061] As a preferred embodiment of the above scheme, in the inverted image group G2, the fifth lens L5 has a negative optical power, -0.87≤Φ5≤-0.85; the sixth lens L6 has a positive optical power, 1.17≤Φ6≤1.19; the seventh lens L7 has a negative optical power, -0.78≤Φ7≤-0.76; and the eighth lens L8 has a positive optical power, 1.16≤Φ8≤1.18.

[0062] As a preferred embodiment of the above scheme, in the eyepiece group G3, the ninth lens L9 has a positive optical power, 0.44≤Φ9≤0.46; the tenth lens L10 has a positive optical power, 0.63≤Φ 10 ≤0.65; the eleventh lens L11 has negative power, -0.32≤Φ 11 ≤-0.30.

[0063] As a preferred embodiment of the above scheme, in the objective lens group G1, the material refractive index of the protection glass P1 is 1.75≤Nd1≤1.85, and the Abbe number is 70≤Vd1≤80; the material refractive index of the first lens L1 is 1.85≤Nd1≤1.95, and the Abbe number is 30≤Vd1≤40; the material refractive index of the parallel plate P2 is 1.75≤Nd1≤1.85, and the Abbe number is 20≤Vd1≤30; the material refractive index of the second lens L2 is 1.80≤Nd2≤1.90, and the Abbe number is 40≤Vd2≤50; the material refractive index of the third lens L3 is 1.70≤Nd3≤1.80, and the Abbe number is 40≤Vd3≤50; the material refractive index of the fourth lens is 1.75≤Nd4≤1.85, and the Abbe number is is 20≤Vd4≤30; in the inverted image group G2, the material refractive index of the fifth lens L5 is 1.95≤Nd5≤2.05, and the Abbe number is 20≤Vd5≤30; the material refractive index of the sixth lens L6 is 1.70≤Nd6≤1.80, and the Abbe number is 40≤Vd6≤50; the material refractive index of the seventh lens L7 is 1.90≤Nd7≤2.00, and the Abbe number is 20≤Vd7≤30; the material refractive index of the eighth lens L8 is 1.70≤Nd8≤1.80, and the Abbe number is 40≤Vd8≤50; in the eyepiece group G3, the material refractive index of the ninth lens L9 is 1.55≤Nd9≤1.65, and the Abbe number is 60≤Vd9≤70; the material refractive index of the tenth lens L10 is 1.45≤Nd 10 ≤1.55, Abbe number is 40≤Vd 10 ≤50; the refractive index of the material of the eleventh lens L11 is 1.90≤Nd 11 ≤2.00, Abbe number is 20≤Vd 11 ≤30.

[0064] In this embodiment, the third lens L3 and the fourth lens L4 form a doublet lens, the fifth lens L5 and the sixth lens L6 form a doublet lens, the seventh lens L7 and the eighth lens L8 form a doublet lens, and the tenth lens L10 and the eleventh lens L11 form a doublet lens.

[0065] In this embodiment, surface 1 and surface 2 are protective glasses made of sapphire. The aperture is the ninth surface, and the curvature radius of all lenses is different, so that the problem of eccentricity can be reduced during assembly, while obtaining good imaging quality.

[0066] The focal length of the ultra-fine rigid endoscope described in this embodiment is 1.73 and the F / # is 13.85.

[0067] The object side numerical aperture of the ultra-thin rigid endoscope described in this embodiment is up to 0.0056.

[0068] Figure 4 This is the MTF curve diagram on the surface of an ultra-fine rigid fiber optic endoscope with integrated illumination and image transfer optical paths described in this embodiment, which respectively gives the meridian and sagittal MTF curves of 0 field of view, 0.707 field of view and 1.0 field of view, as well as the MTF curve under diffraction limit conditions. The design has almost reached the diffraction limit, indicating that the imaging quality of the ultra-fine rigid endoscope is excellent.

[0069] Example 2

[0070] This embodiment is an ultra-fine rigid fiber optic endoscope with integrated illumination and image transfer optical paths. Its mechanical structure and optical system are the same as those of embodiment 1.

[0071] Compared with Example 1, Example 2 is another excellent solution for achieving high-quality imaging. In the matched optical parameters, the radius of curvature, thickness, optical power, aperture, lens spacing and working distance of the lens of Example 2 are all different from those of Example 1, but the lens materials are the same.

[0072] The focal lengths of the lenses in this embodiment are f1, f2, f3, f4, f5, f6, f7, f8, f9, f 10 、f 11 ; The apertures of each lens are D1, D2, D3, D4, D5, D6, D7, D8, D9, D 10 , D 11 ; The relationship between the focal length and the aperture of each lens satisfies the following conditions:

[0073] -0.9≤f1 / D1≤-0.7;

[0074] 2.1≤f2 / D2≤2.3;

[0075] 0.8≤f3 / D3≤1.0;

[0076] -1.8≤f4 / D4≤-1.6;

[0077] -1.3≤f5 / D5≤-1.5;

[0078] 1.1≤f6 / D6≤1.3;

[0079] -1.6≤f7 / D7≤-1.8;

[0080] 1.2≤f8 / D8≤1.4;

[0081] 2.9≤f9 / D9≤3.1;

[0082] 3.0≤f 10 / D 10 ≤3.2;

[0083] -5.5≤f 11 / D 11 ≤-5.3;

[0084] As a preferred embodiment of the above scheme, in the objective lens group G1, the protective glass P1 has no optical power; the first lens L1 has a negative optical power, -1.76≤Φ1≤-1.74; the parallel plate P2 has no optical power; the second lens L2 has a positive optical power, 0.73≤Φ2≤0.75; the third lens L3 has a positive optical power, 1.60≤Φ3≤1.62; the fourth lens L4 has a negative optical power, -0.85≤Φ4≤-0.83;

[0085] As a preferred embodiment of the above scheme, in the inverted image group G2, the fifth lens L5 has a negative focal power, -0.87≤Φ5≤-0.85; the sixth lens L6 has a positive focal power, 1.16≤Φ6≤1.18; the seventh lens L7 has a negative focal power, -0.78≤Φ7≤-0.76; the eighth lens L8 has a positive focal power, 1.16≤Φ8≤1.18;

[0086] As a preferred embodiment of the above scheme, in the eyepiece group G3, the ninth lens L9 has a positive optical power, 0.45≤Φ9≤0.47; the tenth lens L10 has a positive optical power, 0.63≤Φ 10 ≤0.65; the eleventh lens L11 has negative power, -0.33≤Φ 11 ≤-0.31.

[0087] In this embodiment, surface 1 and surface 2 are protective glasses made of sapphire. The aperture is the ninth surface, and the curvature radius of all lenses is different, so that the problem of eccentricity can be reduced during assembly, while obtaining good imaging quality.

[0088] The lenses of the ultra-fine rigid fiber optic endoscope described in this embodiment have compatible optical parameters, so that the mechanical aperture of the insertion part of the ultra-fine rigid endoscope is less than 1mm, the working distance is 30mm, and the aperture of the optical system of the insertion part is 0.4-0.8mm.

[0089] The focal length of the ultra-fine rigid endoscope described in this embodiment is 1.62, and the F / # (number) is 13.64.

[0090] The object side numerical aperture of the ultra-thin rigid endoscope described in this embodiment reaches 0.0020.

[0091] The image acquisition end at the front end and the output end at the rear end of the optical fiber image transmission bundle described in this embodiment are respectively connected behind the endoscope objective lens group and in front of the inverted image group through coupling optical glue. The cold light source transmits light to the optical system and the object surface through the light guiding part, and completes imaging on the image sensor.

[0092] Figure 5 This is the MTF curve diagram on the surface of an ultra-fine rigid fiber optic endoscope with integrated illumination and image transfer optical paths described in this embodiment, which respectively gives the meridian and sagittal MTF curves of 0 field of view, 0.707 field of view and 1.0 field of view, as well as the MTF curve under diffraction limit conditions. The design has almost reached the diffraction limit, indicating that the imaging quality of the ultra-fine rigid endoscope is excellent.

[0093] The above detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0094] It should be noted that like reference numerals and letters denote similar items in the drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths, characterized in that: It includes a shell, a cold light source, a light guide port, an image transfer system, an optical system and a cubic beam splitter prism; the optical system includes an objective lens group G1, an inverted image group G2 and an eyepiece group G3; the image transfer system includes an optical fiber image transmission bundle F; the objective lens group G1, the optical fiber image transmission bundle F, the inverted image group G2, the eyepiece group G3 and the cubic beam splitter prism SP are placed in sequence; the cold light source is connected to the light guide port through a light guide beam for illumination, and the illumination light passes through the cubic beam splitter prism SP, the eyepiece group G3, the inverted image group G2, the optical fiber image transmission bundle F and the objective lens group G1 in sequence and then is transmitted to the object surface, and the reflected light of the object passes through the objective lens group G1, the optical fiber image transmission bundle F, the inverted image group G2, the eyepiece group G3 and the cubic beam splitter prism SP in sequence and then is received by the image surface to form an image.

2. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 1, characterized in that: The lenses of the optical system have matching parameters, so that the optical system aperture of the insertion part of the ultra-fine rigid optical fiber endoscope is less than 0.4-0.8 mm.

3. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 1, characterized in that: The objective lens group G1 includes a protective glass P1, a first lens L1, a parallel plate P2, a second lens L2, a third lens L3, and a fourth lens L4 in sequence; the inverted image group G2 includes a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 in sequence; the eyepiece group G3 includes a ninth lens L9, a tenth lens L10, and an eleventh lens L11 in sequence.

4. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 3, characterized in that: The focal lengths of the first lens L1 to the eleventh lens L11 are f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, f21, f22, f33, f4, f5, f6, f7, f8, f9, f10, f 10 、f 11 The clear apertures of the first lens L1 to the eleventh lens L11 are D1, D2, D3, D4, D5, D6, D7, D8, D9, D 10 , D 11 ; The relationship between the focal length and the aperture of each lens satisfies the following conditions: -0.9~-0.8≤f1 / D1≤-0.7~-0.6; 2.0~2.1≤f2 / D2≤2.2~2.3; 0.7~0.8≤f3 / D3≤1.0~1.1; -1.9~-1.8≤f4 / D4≤-1.7~-1.6; -1.6~-1.5≤f5 / D5≤-1.3~-1.2; 1.0~1.1≤f6 / D6≤1.2~1.3; -1.9~-1.8≤f7 / D7≤-1.5~-1.4; 1.1~1.2≤f8 / D8≤1.3~1.4; 2.8~2.9≤f9 / D9≤3.0~3.1; 3.0~3.1≤f 10 / D 10 ≤3.2~3.3; -5.5~-5.4≤f 11 / D 11 ≤-5.3~-5.2。 5. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 3, characterized in that: In the objective lens group G1, the protective glass P1 has no optical power; the first lens L1 has a negative optical power, -1.77~-1.76≤Φ1≤-1.74~-1.73; the parallel plate P2 has no optical power; the second lens L2 has a positive optical power, 0.72~0.73≤Φ2≤0.74~0.75; the third lens L3 has a positive optical power, 1.60~1.61≤Φ3≤1.62~1.63; the fourth lens L4 has a negative optical power, -0.85~-0.84≤Φ4≤-0.83~-0.82; in the inverted image group G2, the fifth lens L5 has a negative optical power. The sixth lens L6 has a positive focal power, 1.17 to 1.16 ≤ Φ6 ≤ 1.18 to 1.19; the seventh lens L7 has a negative focal power, -0.79 to -0.78 ≤ Φ7 ≤ -0.76 to -0.75; the eighth lens L8 has a positive focal power, 1.15 to 1.16 ≤ Φ8 ≤ 1.17 to 1.18; in the eyepiece group G3, the ninth lens L9 has a positive focal power, 0.44 to 0.45 ≤ Φ9 ≤ 0.46 to 0.47; the tenth lens L10 has a positive focal power, 0.62 to 0.63 ≤ Φ 10 ≤0.64~0.65; the eleventh lens L11 has a negative optical power, -0.33~-0.32≤Φ 11 ≤-0.31~-0.

30.

6. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 3, characterized in that: In the objective lens group G1, the material refractive index of the protection glass P1 is 1.75≤Nd1≤1.85, and the Abbe number is 70≤Vd1≤80; the material refractive index of the first lens L1 is 1.85≤Nd1≤1.95, and the Abbe number is 30≤Vd1≤40; the material refractive index of the parallel plate P2 is 1.75≤Nd1≤1.85, and the Abbe number is 20≤Vd1≤30; the material refractive index of the second lens L2 is 1.80≤Nd2≤1.90, and the Abbe number is 40≤Vd2≤50; the material refractive index of the third lens L3 is 1.70≤Nd3≤1.80, and the Abbe number is 40≤Vd3≤50; the material refractive index of the fourth lens is 1.75≤Nd4≤1.85, and the Abbe number is 20≤Vd4≤1.85 d4≤30; in the inverted image group G2, the material refractive index of the fifth lens L5 is 1.95≤Nd5≤2.05, and the Abbe number is 20≤Vd5≤30; the material refractive index of the sixth lens L6 is 1.70≤Nd6≤1.80, and the Abbe number is 40≤Vd6≤50; the material refractive index of the seventh lens L7 is 1.90≤Nd7≤2.00, and the Abbe number is 20≤Vd7≤30; the material refractive index of the eighth lens L8 is 1.70≤Nd8≤1.80, and the Abbe number is 40≤Vd8≤50; in the eyepiece group G3, the material refractive index of the ninth lens L9 is 1.55≤Nd9≤1.65, and the Abbe number is 60≤Vd9≤70; the material refractive index of the tenth lens L10 is 1.45≤Nd 10 ≤1.55, Abbe number is 40≤Vd 10 ≤50; the refractive index of the material of the eleventh lens L11 is 1.90≤Nd 11 ≤2.00, Abbe number is 20≤Vd 11 ≤30.

7. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 3, characterized in that: The distance between the second lens L2 and the third lens L3 is 1.98 mm to 2.02 mm; the aperture is located between the second lens L2 and the third lens L3; the distance between the sixth lens L6 and the seventh lens L7 is 2.98 mm to 3.02 mm; the distance between the eighth lens L8 and the ninth lens L9 is 2.20 mm to 2.24 mm; the distance between the ninth lens L9 and the tenth lens L10 is 2.14 mm to 2.18 mm.

8. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 3, characterized in that: The third lens L3 and the fourth lens L4 form a doublet lens, the fifth lens L5 and the sixth lens L6 form a doublet lens, the seventh lens L7 and the eighth lens L8 form a doublet lens, and the tenth lens L10 and the eleventh lens L11 form a doublet lens.

9. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 1, characterized in that: The size range of the optical fiber image transmission bundle is diameter Φ0.35mm*length L50mm~5000mm; the image acquisition end at the front end and the output end at the rear end of the optical fiber image transmission bundle are respectively connected behind the endoscope objective lens group and in front of the inverted image group through coupling optical glue.

10. The ultra-fine rigid optical fiber endoscope with integrated illumination and image transfer optical paths as claimed in claim 1, characterized in that: The size of the cubic beam splitter prism ranges from 3mm*3mm to 8mm*8mm; the cubic beam splitter prism is fixed at the connection between the light guide port and the optical system through the endoscope base.

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