Infrared Endoscope Eyepiece Optical System for Flow Blood Imaging

Abstract

The present invention provides an infrared endoscope eyepiece optical system suitable for imaging flowing blood, which is characterized in that it is composed of a first lens, a second lens and a third lens sequentially arranged along the optical axis from the object surface to the image surface; the surface of the first lens facing the object surface is defined as the first surface, and the surface facing the image surface is defined as the second surface; the surface of the second lens facing the object surface is defined as the third surface, and the surface facing the image surface is defined as the fourth surface; the surface of the third lens facing the object surface is defined as the fifth surface, and the surface facing the image surface is defined as the sixth surface. Through the optimization of the lens structure, the present invention realizes the advantages of small image plane distortion while ensuring a compact structure and fewer lenses used, can be better coupled with the front imaging fiber bundle, and all lenses adopt spherical structures, reducing the processing difficulty and saving costs.

Description

Technical Field

[0001] The present invention relates to an infrared endoscope adapter lens optical system suitable for imaging flowing blood, belonging to the technical field of medical devices. Background Art

[0002] Endoscope technology, which combines modern optics, precision machinery, and electronic technology, has been widely used since its invention. It not only provides non-destructive testing during industrial production without disassembling or stopping equipment operation, but also has developed many categories such as oral endoscopes, laparoscopes, and otolaryngology endoscopes in the medical field, effectively improving the detection rate of lesions and the surgical recovery ability.

[0003] Endoscopes are usually placed in media with low scattering and weak absorption such as air. Therefore, using visible light as the light source can achieve excellent imaging effects, but this cannot meet the usage requirements in certain specific solution environments. In the medical field, with the continuous development of interventional surgery technology, people have begun to use near-infrared light as the light source for imaging in the blood environment. Because the absorption and scattering coefficients of visible light in such media are relatively large, it is difficult to achieve effective light transmission, and thus it is impossible to image the target substance. To solve this problem, relevant personnel have proposed a new type of endoscope based on an infrared light source. This endoscope uses infrared laser in the near-infrared band as the light source of the endoscope, realizing visualization in the blood environment.

[0004] Currently, the main endoscopes on the market mainly use visible light as the light source, and related matching optical elements such as eyepieces can only support visible light. This results in the lack of available eyepieces for endoscopes using infrared laser as the light source, and an optical imaging system cannot be formed without an eyepiece component. Summary of the Invention

[0005] The object of the present invention is to provide an eyepiece lens adapted to an infrared endoscope, which has a simple structure, is small and compact, has small geometric distortion, and operates in the near-infrared band.

[0006] To achieve the above object, the technical solution of the present invention is to provide an infrared endoscope eyepiece optical system suitable for imaging flowing blood, characterized in that it is composed of a first lens, a second lens, and a third lens arranged in sequence along the optical axis from the object plane to the image plane;

[0007] Define the surface of the first lens facing the object plane as the first surface, and the surface facing the image plane as the second surface; define the surface of the second lens facing the object plane as the third surface, and the surface facing the image plane as the fourth surface; define the surface of the third lens facing the object plane as the fifth surface, and the surface facing the image plane as the sixth surface, then there is:

[0008] The first surface is convex towards the object surface with a radius of curvature equal to 19.950 mm, and the second surface is convex towards the image surface with a radius of curvature equal to -21.980 mm; the third surface is convex towards the object surface with a radius of curvature equal to 14.500 mm, and the fourth surface is a plane with an infinite radius of curvature; the fifth surface is convex towards the object surface with a radius of curvature equal to 7.521 mm, and the sixth surface is convex towards the object surface with a radius of curvature equal to 7.651 mm.

[0009] Preferably, the first lens has a positive optical power with a focal length f1 = 21.430 mm; the second lens has a positive optical power with a focal length f2 = 28.787 mm; the third lens has a positive optical power with a focal length f3 = 87.286 mm.

[0010] Preferably, the central thickness of the first lens is 3.900 mm; the central thickness of the second lens is 3.200 mm; the central thickness of the third lens is 3.520 mm.

[0011] Preferably, the distance between the second surface and the third surface is 0.800 mm; the distance between the fourth surface and the fifth surface is 0.199 mm.

[0012] Preferably, the clear apertures of the first lens, the second lens, and the third lens are all less than 12 mm, and the diameter sizes are all 10 mm.

[0013] Preferably, the first lens, the second lens, and the third lens are all spherical lenses made of BK7 material.

[0014] Preferably, the optimal working band of the infrared endoscope eyepiece optical system is 1.25 - 1.35 microns, and the optical tube length is less than 30 mm.

[0015] Through the optimization of the lens structure, the present invention realizes the advantages of small image plane distortion while ensuring a compact structure and a small number of lenses used. It can be better coupled with the front imaging fiber bundle, and all lenses adopt spherical structures, reducing the processing difficulty and saving costs.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. In view of the special working requirements of the infrared endoscope applicable to flowing blood, the present invention designs and optimizes an objective optical system adapted thereto. Through ZEMAX simulation, based on the imaging indicators of the near-infrared laser that can fully support the near-infrared band, not only the effective coupling of the system with the front imaging fiber bundle is realized, but also the system size is strictly controlled to achieve a small and compact structure.

[0018] 2. The infrared endoscope eyepiece optical system designed by the present invention for imaging flowing blood uses spherical lenses, which reduces the processing difficulty and cost and is conducive to large-scale popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of an infrared endoscope eyepiece optical system for imaging flowing blood according to the present invention;

[0020] Figure 2 It is a simulation diagram of the MTF optical transfer function curve of the eyepiece in the embodiment of the present invention;

[0021] Figure 3 It is a simulation diagram of the relative illuminance of the eyepiece in the embodiment of the present invention;

[0022] Figure 4 It is a simulation diagram of the distortion of the eyepiece in the embodiment of the present invention;

[0023] Figure 5 It is a schematic diagram of the combined use of the eyepiece and the conversion lens in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following further elaborates the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0025] The structure of an infrared endoscope eyepiece optical system provided by the present invention is as Figure 1 shown, and it is composed of a first lens 1, a second lens 2, and a third lens 3 arranged in sequence along the optical axis from the object surface to the image surface. The surface of the first lens 1 facing the object surface is defined as the first surface 11, and the surface facing the image surface is defined as the second surface 12. The surface of the second lens 2 facing the object surface is defined as the third surface 21, and the surface facing the image surface is defined as the fourth surface 22. The surface of the third lens 3 facing the object surface is defined as the fifth surface 31, and the surface facing the image surface is defined as the sixth surface 32.

[0026] The first lens 1 has a positive optical power, and the focal length f1 = 21.430 mm. The first surface 11 is convex toward the object surface, and the radius of curvature is 19.950 mm; the second surface 12 is convex toward the image surface, and the radius of curvature is -21.980 mm. The central thickness of the first lens 1 is 3.900 mm.

[0027] The second lens 2 has a positive optical power, with a focal length f2 = 28.787 mm. The third surface 21 is convex towards the object surface, with a radius of curvature of 14.500 mm; the fourth surface 22 is a plane, with an infinite radius of curvature. The central thickness of the second lens 2 is 3.200 mm.

[0028] The third lens 3 has a positive optical power, with a focal length f3 = 87.286 mm. The fifth surface 31 is convex towards the object surface, with a radius of curvature of 7.521 mm; the sixth surface 32 is convex towards the object surface, with a radius of curvature of 7.651 mm. The central thickness of the third lens 3 is 3.520 mm.

[0029] To ensure a small and compact overall structure, the clear apertures of the first lens 1, the second lens 2, and the third lens 3 in the eyepiece optical system are all less than 12 mm, and the diameter sizes are all 10 mm. Also, the distance between the second surface and the third surface is 0.800 mm; the distance between the fourth surface and the fifth surface is 0.199 mm. To ensure simple processing and reduce costs, the first lens 1, the second lens 2, and the third lens 3 are all spherical lenses made of BK7 material.

[0030] The optimal working wavelength band of the eyepiece optical system provided in this embodiment is 1.25 - 1.35 microns, and the optical tube length is less than 30 mm.

[0031] The application environment based on the above - mentioned embodiment is as follows: There is an imaging fiber bundle with a diameter of 3 mm connected in front. The fiber bundle is composed of multiple single - filament fibers, ensuring that the imaging fiber has a pixel number in the tens of thousands.

[0032] Based on the above - mentioned application environment, as Figure 2 shown, the optimized eyepiece optical system in the above - mentioned embodiment has an MTF greater than 0.62 at the full - field angle with a cut - off frequency of 30 lp / mm. As Figure 3 shown, the optimized eyepiece optical system in the above - mentioned embodiment has a relative illuminance greater than 95% on the image plane, ensuring the lighting uniformity during imaging. As Figure 4 shown, the optimized eyepiece optical system in the above - mentioned embodiment has a distortion less than 2.2% on the image plane.

[0033] The eyepiece optical system provided by the present invention can not only be used alone to see the magnified image of the fiber end face, but also, as Figure 5 shown, be used in combination with the conversion lens proposed in the infrared endoscope adapter lens optical system for flowing blood imaging applied for another case by the present applicant. After magnifying the image of the fiber end face by 2.65 times, it is imaged onto the camera photosensitive surface.

[0034] The above embodiments are only one implementation manner of the present invention. However, the implementation manners of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement manners and are all included in the protection scope of the present invention.

Claims

1. An infrared endoscope eyepiece optical system applicable to flowing blood imaging, characterized in that, It is composed of a first lens, a second lens, and a third lens arranged in sequence along the optical axis from the object surface to the image surface; Define the surface of the first lens facing the object surface as the first surface, and the surface facing the image surface as the second surface; Define the surface of the second lens facing the object surface as the third surface, and the surface facing the image surface as the fourth surface; define the surface of the third lens facing the object surface as the fifth surface, and the surface facing the image surface as the sixth surface, then there are: The first surface is convex towards the object surface with a curvature radius of 19.950 mm, and the second surface is convex towards the image surface with a curvature radius of -21.980 mm; the third surface is convex towards the object surface with a curvature radius of 14.500 mm, and the fourth surface is a plane with an infinite curvature radius; the fifth surface is convex towards the object surface with a curvature radius of 7.521 mm, and the sixth surface is convex towards the object surface with a curvature radius of 7.651 mm; The first lens has a positive optical power, and the focal length f1 = 21.430 mm; the second lens has a positive optical power, and the focal length f2 = 28.787 mm; the third lens has a positive optical power, and the focal length f3 = 87.286 mm; The central thickness of the first lens is 3.900 mm; the central thickness of the second lens is 3.200 mm; the central thickness of the third lens is 3.520 mm; The distance between the second surface and the third surface is 0.800 mm; the distance between the fourth surface and the fifth surface is 0.199 mm; The clear apertures of the first lens, the second lens, and the third lens are all less than 12 mm, and the diameter sizes are all 10 mm; The first lens, the second lens, and the third lens are all spherical lenses made of BK7 material; The optimal working band of the infrared endoscope eyepiece optical system is 1.25 - 1.35 microns, and the optical tube length is less than 30 mm.

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