An endoscopic microscope objective lens for parallel optical coherence tomography system

Abstract

The present invention provides an endoscope microscope objective lens for a parallel optical coherence tomography imaging system, comprising eight lenses, which are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens from the object end to the image end; wherein the sixth lens and the eighth lens have negative optical focal lengths, and the remaining lenses have positive optical focal lengths. The endoscope microscope objective lens, by setting eight lenses of different types and positions, obtains an endoscope microscope objective lens with high-resolution limited imaging and a small lens diameter, i.e., an aperture, and is suitable for the work of collecting image information in clinical practice.

Description

Technical Field

[0001] The invention belongs to the technical field of endoscopic microscopic imaging, and in particular relates to an endoscopic microscopic objective lens used in a parallel optical coherence tomography imaging system. Background Art

[0002] In the process of clinical diagnosis and treatment, endoscopic equipment is often needed. The equipment can send the probe to the designated part through the natural channels of the human body and transmit the collected image information to the outside of the body for the doctor to diagnose. However, these devices can only provide image information of the surface of the tissue and have limited magnification. In order to further confirm the diagnosis, it is often necessary to pass the biopsy forceps through the working channel of the endoscope to obtain tissue specimens. This not only brings pain to the patient and increases the risk of lesion spread, but also requires a long time to wait for the pathological test results, resulting in low diagnosis and treatment efficiency.

[0003] Based on the above problems, people have proposed endoscopic microscope systems, including endoscopic microscopes based on traditional optics, endoscopic microscopes based on laser confocal imaging, and endoscopic microscopes based on optical coherence tomography. The common feature of these systems is that a micro-microscope with an image transmission fiber bundle reaches the lesion through the working channel of a traditional endoscope. The micro-microscope magnifies the tissue and images it on the end face of the image transmission fiber bundle and transmits it to the camera outside the body through the image transmission fiber bundle, thereby realizing endoscopic microscopic imaging of the lesion.

[0004] The working channel of a traditional endoscope is very narrow, with a diameter between 1.2mm and 4.2mm. In order for the microscope objective to pass through the working channel smoothly, its outer diameter must be very small. Since the resolution of the microscope is positively correlated with the aperture, the existing endoscopic microscope objective lenses generally sacrifice a certain resolution in order to meet the large numerical aperture requirements of the object side; or sacrifice the flexibility of the objective lens for the sake of resolution. For example, in the patent document "CN200510029661.8", a refractive index matching liquid is added between the surface and the lens, which will bring great obstacles to the assembly and maintenance of the lens; therefore, how to achieve high-resolution microscopic imaging while meeting the large numerical aperture requirements of the object side is a challenge and research direction in the field of endoscopic microscopic imaging technology. Summary of the invention

[0005] In view of this, one of the objectives of the present invention is to provide an endoscopic microscope objective lens for a parallel optical coherence tomography system, which can reduce the lens diameter of the endoscopic microscope objective lens.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] An endoscope microscope objective lens for a parallel optical coherence tomography imaging system comprises eight lenses, which are, from the object end to the image end, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; wherein the distance between the fourth lens and the fifth lens is 3 mm to 5 mm, and a light barrier is arranged between the fourth lens and the fifth lens;

[0008] The distance between the sixth lens and the seventh lens is 1.5mm-3mm; the distance between other two adjacent lenses is 0.05mm-0.3mm; the sixth lens and the eighth lens have negative focal powers, and the other lenses have positive focal powers.

[0009] Furthermore, the object side surface of the first lens is a flat surface, and the image side surface is a convex surface;

[0010] The object side surfaces of the second lens, the third lens and the sixth lens are concave, and the image side surfaces are convex;

[0011] The object side surfaces of the fourth lens and the fifth lens are convex, and the image side surfaces are also convex;

[0012] The object side surfaces of the seventh lens and the eighth lens are convex, and the image side surfaces are concave.

[0013] Furthermore, the object plane is 60 μm away from the first lens.

[0014] Furthermore, the image side surface of the first lens has a curvature radius of 1.23 mm, a thickness of 0.4 mm, and a material refractive index of 1.514.

[0015] Furthermore, the object side surface of the second lens has a curvature radius of 0.99 mm, the image side surface has a curvature radius of 0.95 mm, and the material refractive index is 1.835.

[0016] Furthermore, the object side surface curvature radius of the third lens is 5.42 mm, the image side surface curvature radius is 1.82 mm, and the material refractive index is 1.835.

[0017] Furthermore, the object side surface curvature radius of the fourth lens is 4.44 mm, the image side surface curvature radius is 8.88 mm, and the material refractive index is 1.697.

[0018] Furthermore, the fifth lens has an object side surface curvature radius of 4.73 mm, an image side surface curvature radius of 7.80 mm, and a material refractive index of 1.835.

[0019] Furthermore, the object side surface of the sixth lens has a curvature radius of 2 mm, the image side surface has a curvature radius of 4.46 mm, and the material refractive index is 1.847.

[0020] Furthermore, the seventh lens has an object side surface curvature radius of 2.22 mm, an image side surface curvature radius of 13.37 mm, and a material refractive index of 1.835.

[0021] The radius of curvature of the object side of the eighth lens is 1.02mm, the radius of curvature of the image side is 0.50mm, and the refractive index of the material is 1.835.

[0022] The present invention provides an endoscopic microscope objective lens for a parallel optical coherence tomography system. By setting 8 lenses of different types and positions, an endoscopic microscope objective lens with high-resolution limited imaging and a small lens diameter, i.e., an aperture, is obtained, which is suitable for the work of collecting image information in clinical practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0024] Figure 1 It is a schematic structural diagram of an embodiment of an endoscopic microscope objective lens for a parallel optical coherence tomography imaging system of the present invention;

[0025] Figure 2 A dot matrix diagram of an embodiment of an endoscopic microscope objective lens for a parallel optical coherence tomography system of the present invention;

[0026] Figure 3 A field curvature and F-distortion curve diagram of an embodiment of an endoscopic microscope objective lens for a parallel optical coherence tomography imaging system of the present invention;

[0027] Figure 4 FIG. 4 is an MTF curve diagram of an embodiment of an endoscopic microscope objective lens for a parallel optical coherence tomography system according to the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0029] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0030] refer to Figure 1 , is a structural diagram of an endoscopic microscope objective lens for a parallel optical coherence tomography imaging system in this embodiment. Specifically, an endoscopic microscope objective lens for a parallel optical coherence tomography imaging system includes eight lenses, which are a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8 from the object end to the image end;

[0031] Preferably, the distance between the fourth lens 4 and the fifth lens 5 is 3mm-5mm, and a light barrier is arranged in the middle;

[0032] The distance between the sixth lens 6 and the seventh lens 7 is 1.5 mm-3 mm; the distance between other two adjacent lenses is 0.05 mm-0.3 mm; the sixth lens 6 and the eighth lens 8 have negative focal powers, and the remaining lenses have positive focal powers.

[0033] In this embodiment, the object side surface of the first lens 1 is a plane, the image side surface is a convex surface, the radius of curvature is 1.23 mm, the thickness is 0.4 mm, and the material refractive index is 1.514;

[0034] The object side surface of the second lens 2 is concave with a curvature radius of 0.99 mm, the image side surface is convex with a curvature radius of 0.95 mm, and the material refractive index is 1.835;

[0035] The object side surface of the third lens 3 is concave with a curvature radius of 5.42 mm, the image side surface is convex with a curvature radius of 1.82 mm, and the material refractive index is 1.835;

[0036] The object side surface of the fourth lens 4 is convex, with a radius of curvature of 4.44 mm, the image side surface is convex, with a radius of curvature of 8.88 mm, and the material refractive index is 1.697;

[0037] The optical lens is located 0.06mm behind the fourth lens, with a thickness of 3.45mm and a mechanical aperture of 1.76mm;

[0038] The object side surface of the fifth lens 5 is convex, with a radius of curvature of 4.73 mm, the image side surface is convex, with a radius of curvature of 7.80 mm, and the material refractive index is 1.835;

[0039] The object side surface of the sixth lens 6 is concave with a curvature radius of 2 mm, the image side surface is convex with a curvature radius of 4.46 mm, and the material refractive index is 1.847;

[0040] The object side surface of the seventh lens 7 is convex, with a radius of curvature of 2.22 mm, the image side surface is concave, with a radius of curvature of 13.37 mm, and the material refractive index is 1.835;

[0041] The object side surface of the eighth lens 8 is convex with a curvature radius of 1.02 mm, the image side surface is concave with a curvature radius of 0.50 mm, and the material refractive index is 1.835.

[0042] Specific lens structure parameters are shown in Table 1 below (length unit: mm):

[0043] Table 1 Lens structure parameters

[0044]

[0045]

[0046] In this embodiment, the object-side numerical aperture NA=1.0, the image-side numerical aperture NA=0.3, the image-side of the endoscopic microscope objective lens for the parallel optical coherence tomography imaging system is coupled with the end face of the image transmission fiber bundle connected to the endoscopic microscope objective lens, and the object-side numerical aperture and the numerical aperture of the image transmission fiber bundle can achieve a good match, which can improve the transmission efficiency.

[0047] Preferably, when using the endoscopic microscope objective lens for the parallel optical coherence tomography imaging system in this embodiment, the microscope objective lens can be raised into the human body or organism to collect image information. At this time, the object plane is 60 μm away from the first lens, and the space between the object plane and the first lens 1 is filled with biological tissue fluid, and the refractive index of the tissue fluid is n=1.39.

[0048] When the incident wavelength is 850 nm, the point diagram of the endoscope objective lens used in the parallel optical coherence tomography imaging system in this embodiment is as follows: Figure 2 As shown; under the condition of 850 wavelength, the diameter of the Airy disk is 1.805μm, and the root mean square radius values ​​​​RMS radius at each position on the point diagram are 0.62μm, 0.662μm, 0.788μm, 1.007μm, 1.278μm, and 1.913μm respectively. It can be seen that within the field of view of 200μm, the RMS radius is equivalent to the Airy disk radius, and the phase difference has been well corrected.

[0049] Figure 3 The field curvature and F-distortion of the endoscope microscope objective lens used in the parallel optical coherence tomography imaging system in this embodiment when the incident wavelength is 850nm. It can be seen that within the field of view of 200μm, the distortion is about 2.5%.

[0050] Figure 4: is an MTF curve diagram of the endoscope microscope objective lens used in the parallel optical coherence tomography imaging system in this embodiment when the incident wavelength is 850nm. At the edge of the field of view, at 170pl / mm, the MTF modulus is 0.45.

[0051] The maximum optical aperture outer diameter of the endoscope microscope objective lens used in the parallel optical coherence tomography imaging system in this embodiment is less than 1.8 mm, the optical length is less than 9.67 mm, and the reference Figures 2 to 4 It can be seen that the maximum lens diameter of the endoscopic microscope objective lens for the parallel optical coherence tomography imaging system of the present invention is 1.8 mm, the outer diameter of the lens is smaller, it is suitable for the working channel of clinically collected image information and has high imaging resolution.

[0052] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. An endoscopic microscope objective lens for a parallel optical coherence tomography system, characterized in that: It includes eight lenses, which are the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens from the object end to the image end; wherein, The distance between the fourth lens and the fifth lens is 3mm-5mm, and a light barrier is arranged between the fourth lens and the fifth lens; The distance between the sixth lens and the seventh lens is 1.5mm-3mm; the distance between other two adjacent lenses is 0.05mm-0.3mm; The sixth lens and the eighth lens have negative optical power, and the remaining lenses have positive optical power; the object side surface of the first lens is a plane, and the image side surface is a convex surface; The object side surfaces of the second lens, the third lens and the sixth lens are concave, and the image side surfaces are convex; The object side surfaces of the fourth lens and the fifth lens are convex, and the image side surfaces are also convex; The object side surfaces of the seventh lens and the eighth lens are convex, and the image side surfaces are concave; The object side surface of the second lens has a curvature radius of 0.99 mm, the image side surface has a curvature radius of 0.95 mm, and the material refractive index is 1.835; The object plane is 60 μm away from the first lens; The image side surface of the first lens has a curvature radius of 1.23 mm, a thickness of 0.4 mm, and a material refractive index of 1.514; The object side surface curvature radius of the third lens is 5.42 mm, the image side surface curvature radius is 1.82 mm, and the material refractive index is 1.

835.

2. The endoscopic microscope objective lens for a parallel optical coherence tomography system according to claim 1, characterized in that: The object side surface curvature radius of the fourth lens is 4.44 mm, the image side surface curvature radius is 8.88 mm, and the material refractive index is 1.

697.

3. The endoscopic microscope objective lens for a parallel optical coherence tomography system according to claim 1, characterized in that: The fifth lens has an object side surface with a curvature radius of 4.73 mm, an image side surface with a curvature radius of 7.80 mm, and a material refractive index of 1.

835.

4. The endoscopic microscope objective lens for a parallel optical coherence tomography system according to claim 1, characterized in that: The object side surface of the sixth lens has a curvature radius of 2 mm, the image side surface has a curvature radius of 4.46 mm, and the material refractive index is 1.

847.

5. The endoscopic microscope objective lens for a parallel optical coherence tomography system according to claim 1, characterized in that: The seventh lens has an object side surface with a curvature radius of 2.22 mm, an image side surface with a curvature radius of 13.37 mm, and a material refractive index of 1.835; The radius of curvature of the object side of the eighth lens is 1.02mm, the radius of curvature of the image side is 0.50mm, and the refractive index of the material is 1.835.

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