阅读说明：本技术 一种大视场微型显微物镜 (Large-view-field micro microscope objective ) 是由 付玲 李华 刘谦 郑刚 骆清铭 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种大视场微型显微物镜,沿其光轴方向从物端到像端依次包括：物面、具有正屈亮度的第一透镜、具有正屈亮度的第二透镜、第三透镜、具有正屈亮度的第四透镜、具有负屈亮度的第五透镜、具有负屈亮度的第六透镜以及成像面；由物面发射的光线依次经过所述第一透镜、第二透镜、第三透镜、第四透镜、第五透镜和第六透镜后成像于成像面上。本发明提供的大视场微型显微物镜的尺寸小,有效成像视场可达570μm。(The invention discloses a large-view-field micro-objective, which sequentially comprises the following components from an object end to an image end along the optical axis direction: the imaging lens comprises an object plane, a first lens with positive bending brightness, a second lens with positive bending brightness, a third lens, a fourth lens with positive bending brightness, a fifth lens with negative bending brightness, a sixth lens with negative bending brightness and an imaging plane; and light rays emitted by the object plane sequentially pass through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens and then are imaged on an imaging plane. The large-view-field micro microscope objective provided by the invention has small size, and the effective imaging view field can reach 570 mu m.)

1. The utility model provides a miniature microobjective of big visual field which characterized in that includes in proper order from the object end to the image end along its optical axis direction: the imaging lens comprises an object plane, a first lens with positive bending brightness, a second lens with positive bending brightness, a third lens, a fourth lens with positive bending brightness, a fifth lens with negative bending brightness, a sixth lens with negative bending brightness and an imaging plane;

the light rays emitted by the object plane sequentially pass through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens and then are imaged on the imaging plane.

2. The large-field micro-microscope objective of claim 1, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy the following condition: R1F is more than 0, and R1R is less than 0; R2F < R2R < 0; R3F > R3R > 0; R4F is more than 0, and R4R is less than 0; R5F > R5R > 0; R6F < R6R < 0; R7F > R7R > 0;

wherein R1F is a radius of curvature of a first object end surface of the first lens; R1R is the radius of curvature of the first image end surface of the first lens; R2F is the radius of curvature of the second end surface of the second lens; R2R is the radius of curvature of the second image end surface of the second lens; R3F is a radius of curvature of a third object end surface of one of the third lenses having negative refractive power; R3R is a radius of curvature of a third image end surface of a lens having negative dioptric brightness among the third lenses; R4F is a radius of curvature of a fourth object end surface of one of the third lenses having positive refractive power; R4R is a radius of curvature of a fourth image end surface of a lens having positive refractive power among the third lenses; R5F is a radius of curvature of a fifth object end surface of the fourth lens; R5R is a radius of curvature of a fifth image end surface of the fourth lens; R6F is a radius of curvature of a sixth object end surface of the fifth lens; R6R is a radius of curvature of a sixth image end surface of the fifth lens; R7F is a radius of curvature of a seventh object end surface of the sixth lens; R7R is a radius of curvature of the seventh image end surface of the sixth lens.

3. The large-field micro-microscope objective of claim 1 or 2, wherein the first lens has a first object-end surface and a first image-end surface,

the second lens has a second object end surface and a second image end surface;

the third lens is provided with a third object end surface, a third image end surface, a fourth object end surface and a fourth image end surface, and the third image end surface and the fourth object end surface are closely superposed;

the fourth lens has a fifth object end surface and a fifth image end surface,

the fifth lens has a sixth object end surface and a sixth image end surface,

the sixth lens has a seventh object end surface and a seventh image end surface.

4. The large-field micro-microscope objective of claim 3, wherein the first lens is a plano-convex lens and the first object end surface is planar.

5. The large field micro microscope objective of claim 3, wherein the third lens is a cemented doublet comprising one lens with negative dioptric intensity and one lens with positive dioptric intensity.

6. The large-field micro microscope objective of any one of claims 3 to 5, wherein the sixth lens is an aspheric meniscus lens.

7. The large-field micro microscope objective of any one of claims 1 to 6, wherein the object plane is aspheric and the material of the object plane is SEAWATER.

Technical Field

The invention belongs to the field of medical images, and particularly relates to a large-field-of-view micro objective and a probe comprising the same.

Background

Digestive tract tumors have the characteristics of high morbidity and high lethality. The incidence and the fatality rate of the digestive tract tumor are more prominent in China. The survival time of the patients can be obviously improved by early diagnosis and treatment of the digestive tract tumor. Early manifestations of digestive tract lesions will first be reflected in the microstructure and morphology of digestive tract mucosal cells, and then gradually manifest themselves in macroscopic morphology. Therefore, having a high resolution detection method at the cellular level is crucial for the early diagnosis of cancer of the digestive tract.

The confocal endoscope is one of the most advanced endoscopic imaging technologies at present, has micron-scale optical resolution, can perform real-time and accurate observation on the forms of cells and tissues of the alimentary tract mucosa during common endoscopic examination, and provides a powerful tool for early diagnosis of alimentary tract diseases. The micro objective probe is one of the key technologies of a confocal endoscope, and is used for focusing divergent light emitted by a single optical fiber on a sample to excite fluorescence, and simultaneously collecting the fluorescence of the sample and coupling the fluorescence into the single optical fiber of an optical fiber bundle.

The prior patent literature is searched and found that the Chinese invention has the following application numbers: CN201710639015.6, the patent itself with publication date of 2017, 10 and 27 is as follows: ' a micro microscope objective used in alimentary canal, belonging to medical image field. The micro microscope objective lens used in the alimentary canal is provided with an outer diameter of 3.5mm, and sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object end to an image end along the optical axis direction, wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens satisfy the following conditional expressions: R1F is more than 0, and R1R is less than 0; R2F > R2R > 0; R3F is more than 0, and R3R is less than 0; R4F > R4R > 0; R5F is more than 0, R5R is less than 0, the first lens is a plano-convex lens, the second lens and the third lens are double-cemented lenses, the second image end surface and the third object end surface are cemented, and the fourth lens is an aspheric meniscus lens. The micro microscope objective lens used in the alimentary canal has small size, can be matched with a fluorescence confocal endoscope for use, enters a human body through a working channel of a conventional enteroscope to carry out clinical diagnosis on intestinal diseases, and can meet various optical performances during diagnosis. The effective field of view of the micro microscope objective is 360 μm. "

The disadvantages are that: (1) the micro microscope objective has an outer diameter of 3.5mm, which is larger than a working channel of a conventional gastroscope, and cannot realize the observation of the upper digestive tract; (2) the effective field of view is 360 μm, and tissue imaging over a larger range, such as 500 μm, cannot be achieved.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a large-field micro microscope objective which has a small size compatible with a conventional gastroscope working channel, has an effective field of view of 570 mu m and can meet the optical performance, and a probe comprising the micro objective.

The invention provides a large-field-of-view micro-objective, which sequentially comprises the following components from an object end to an image end along the optical axis direction: the imaging lens comprises an object plane, a first lens with positive bending brightness, a second lens with positive bending brightness, a third lens, a fourth lens with positive bending brightness, a fifth lens with negative bending brightness, a sixth lens with negative bending brightness and an imaging plane; the light rays emitted by the object plane sequentially pass through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens and then are imaged on the imaging plane; the micro microscope objective can realize tissue imaging with an effective field of view larger than 500 mu m under the condition of being compatible with a conventional gastroscope biopsy channel; the invention adopts the matching of positive and negative lenses and the combination of a spherical lens and an aspherical lens, and uses the aspherical lens to correct aberration on the last lens, thereby realizing effective imaging field of view reaching 570 mu m while ensuring small size.

Further, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens satisfy the following condition: R1F is more than 0, and R1R is less than 0; R2F < R2R < 0; R3F > R3R > 0; R4F is more than 0, and R4R is less than 0; R5F > R5R > 0; R6F < R6R < 0; R7F > R7R > 0; wherein R1F is a radius of curvature of a first object end surface of the first lens; R1R is the radius of curvature of the first image end surface of the first lens; R2F is the radius of curvature of the second end surface of the second lens; R2R is the radius of curvature of the second image end surface of the second lens; R3F is a radius of curvature of a third object end surface of one of the third lenses having negative refractive power; R3R is a radius of curvature of a third image end surface of a lens having negative dioptric brightness among the third lenses; R4F is a radius of curvature of a fourth object end surface of one of the third lenses having positive refractive power; R4R is a radius of curvature of a fourth image end surface of a lens having positive refractive power among the third lenses; R5F is a radius of curvature of a fifth object end surface of the fourth lens; R5R is a radius of curvature of a fifth image end surface of the fourth lens; R6F is a radius of curvature of a sixth object end surface of the fifth lens; R6R is a radius of curvature of a sixth image end surface of the fifth lens; R7F is a radius of curvature of a seventh object end surface of the sixth lens; R7R is a radius of curvature of the seventh image end surface of the sixth lens.

Wherein the first lens has a first object end surface and a first image end surface, and the second lens has a second object end surface and a second image end surface; the third lens is provided with a third object end surface, a third image end surface, a fourth object end surface and a fourth image end surface, and the third image end surface and the fourth object end surface are closely superposed; the fourth lens has a fifth object end surface and a fifth image end surface, the fifth lens has a sixth object end surface and a sixth image end surface, and the sixth lens has a seventh object end surface and a seventh image end surface.

Furthermore, the first lens is a plano-convex lens, and the first object end surface is a plane. The third lens is a double cemented lens comprising one lens with negative dioptre brightness and one lens with positive dioptre brightness. The sixth lens is an aspheric meniscus lens. The object surface is an aspheric surface, the material of the object surface is SEAWATER, and the object surface is similar to a water immersion environment when the alimentary canal tissue is imaged.

The large-field micro microscope objective provided by the invention adopts a mode of matching positive and negative lenses and combining a spherical lens and an aspherical lens, and the aberration of the last lens is corrected by using the aspherical lens, so that the effective imaging field of view reaches 570 mu m while the small size is ensured. The large-field micro microscope objective can be bonded with an optical fiber bundle to form an optical fiber endoscopic probe, is matched with a fluorescence confocal endoscope to be used, enters a human body through a working channel of a conventional gastroscope to carry out clinical diagnosis on esophagus and stomach diseases, and can meet various optical performances during diagnosis.

Drawings

Fig. 1 is a schematic diagram of an optical path structure of a large-field micro-objective provided by the invention.

Fig. 2 is a diagram of the image side dots of fig. 1.

Fig. 3 is a graph of optical path difference of fig. 1 at twelve fields of view along the image side.

FIG. 4 is the image-side field curve and distortion curve of FIG. 1, where (a) is the image-side field curve showing the distance from the current image plane to the paraxial focal plane as a function of field coordinates, and (b) is the distortion curve whose distortion value is defined as the actual chief ray height minus the paraxial chief ray height, divided by the paraxial chief ray height, and multiplied by 100.

Fig. 5 is the MTF curves and chromatic aberration focal shift curves of fig. 1, where (a) is the MTF curves of the meridian plane and the sagittal plane at twelve different positions, and the MTF curves under the diffraction limit condition are given for comparison, and (b) is the chromatic aberration focal shift curve, which shows the optical near focal shift of different wavelengths in the operating wavelength range of the large-field micro microscope objective.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a large-field micro-objective lens, which adopts a mode of matching positive and negative lenses and combining a spherical lens and an aspherical lens, wherein the last lens uses the aspherical lens to correct aberration, and the thickness of a conventional shell is 0.2mm on the premise of ensuring that the clear aperture is less than 2mm, the outer diameter of the large-field micro-objective lens is 2.6mm, and the large-field micro-objective lens sequentially comprises the following components from an object end to an image end along the optical axis direction: the optical imaging lens comprises an object plane, a first lens with positive refraction brightness, a second lens with positive refraction brightness, a third lens consisting of a lens with negative refraction brightness and a lens with positive refraction brightness, a fourth lens with positive refraction brightness, a fifth lens with negative refraction brightness, a sixth lens with negative refraction brightness, and an imaging plane, wherein light rays emitted by the object plane sequentially pass through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens and are finally imaged on the imaging plane. The first lens comprises a first object end surface and a first image end surface, the second lens comprises a second object end surface and a second image end surface, the third lens comprises a third object end surface, a third image end surface, a fourth object end surface and a fourth image end surface, and the third image end surface and the fourth object end surface are closely overlapped; the fourth lens element includes a fifth object end surface and a fifth image end surface, the fifth lens element includes a sixth object end surface and a sixth image end surface, the sixth lens element includes a seventh object end surface and a seventh image end surface, and the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element and the sixth lens element satisfy the following conditional expressions: R1F is more than 0, and R1R is less than 0; R2F < R2R < 0; R3F > R3R > 0; R4F is more than 0, and R4R is less than 0; R5F > R5R > 0; R6F < R6R < 0; R7F > R7R > 0; wherein R1F is a radius of curvature of a first object end surface of the first lens; R1R is the radius of curvature of the first image end surface of the first lens; R2F is the radius of curvature of the second end surface of the second lens; R2R is the radius of curvature of the second image end surface of the second lens; R3F is a radius of curvature of the third object end surface of the lens having negative refractive power of the third lens; R3R is a radius of curvature of the third image end surface of the lens having negative refractive power of the third lens; R4F is a radius of curvature of the fourth object end surface of the lens having positive refractive power of the third lens; R4R is a radius of curvature of the fourth image end surface of the lens having positive refractive power in the third lens; R5F is a radius of curvature of the fifth object-end surface of the fourth lens; R5R is a radius of curvature of the fifth image end surface of the fourth lens; R6F is a radius of curvature of the sixth object end surface of the fifth lens; R6R is a radius of curvature of the sixth image end surface of the fifth lens; R7F is a radius of curvature of the seventh object end surface of the sixth lens; R7R is a curvature radius of a seventh image end surface of the sixth lens element, the first lens element is a plano-convex lens element, the first object end surface is a flat surface, the third lens element is a double cemented lens element, the third image end surface is attached to the fourth object end surface, and the sixth lens element is an aspheric meniscus lens element.

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

As shown in FIG. 1, the magnification of the micro-objective with large field of view provided by the present invention is 2.18, and the effective field of view of the micro-objective can be calculated to be 570 μm according to the clear aperture of the optical fiber bundle. Since the clear aperture is less than 2mm, the conventional housing has a thickness of 0.2mm, and thus the probe with the housing made therefrom will have a diameter of less than 2.6 mm.

Include from the object end to the image end along its optical axis direction in proper order: the imaging lens comprises an object plane, a first lens 10 with positive refraction brightness, a second lens 20 with positive refraction brightness, a third lens consisting of a lens 30 with negative refraction brightness and a lens 40 with positive refraction brightness, a fourth lens 50 with positive refraction brightness, a fifth lens 60 with negative refraction brightness, a sixth lens 70 with negative refraction brightness, and an imaging plane 80, wherein light emitted by the object plane sequentially passes through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens and is finally imaged on the imaging plane.

The object plane is set to be an aspherical surface, matching the irregularity of the tissue. The material is set as SEAWATER, which meets the requirement of water immersion environment during tissue imaging.

The first lens 10 is a plano-convex lens which is convenient to directly contact with tissues, and because the size is reduced, the H-LAF50B which is a glass material with a higher refractive index is selected, so that the light beam is deflected at a large angle. The first lens 10 includes a first object-side surface S11 and a first image-side surface S12, corresponding to a first receiving surface and a first emitting surface of the emitted light from the object plane, respectively.

The second lens 20 is a convex lens and is made of H-LAK 3. And the first lens 10 is matched with the light source to limit the light beam in the whole light path within the effective clear aperture of the micro-objective. The second lens 20 includes a second object end surface S21 and a second image end surface S22 corresponding to a second receiving surface and a second emitting surface, respectively, of the object plane emitted light.

The third lens is a double-cemented lens formed by combining the lens 30 and the lens 40, and chromatic aberration is corrected by matching H-ZF72A with high refractive index and high dispersion coefficient and H-ZLAF89L with high refractive index and low dispersion coefficient respectively; the lens 30 includes a third object end surface S31 and a third image end surface S32, respectively corresponding to a third receiving surface and a third emitting surface of the object plane emitting light; the lens 40 comprises a fourth object end surface S41 and a fourth image end surface S42, which respectively correspond to a fourth receiving surface and a fourth emergent surface of emergent light from the object surface; the third image end surface S32 closely coincides with the fourth object end surface S41.

The fourth lens 50 is a convex lens and made of H-LAK4L, and the fourth lens 50 includes a fifth object-side surface S51 and a fifth image-side surface S52, which correspond to a fifth receiving surface and a fifth emitting surface of the object-side emitted light, respectively.

The fifth lens 60 is a concave lens and is made of H-ZF39, and the fifth lens 60 includes a sixth object-side surface S61 and a sixth image-side surface S62, which correspond to a sixth receiving surface and a sixth emitting surface of the object-side emitted light, respectively. The fourth lens 50 and the fifth lens 60 are made of two materials with similar refractive indexes and larger dispersion coefficient difference, namely H-LAK4L and H-ZF39, and simultaneously adopt a positive and negative lens combination structure, so that part of positive and negative aberrations can be offset, and the aberration correction is facilitated.

The sixth lens 70 is an aspheric meniscus lens, which can be used for correcting spherical aberration and curvature of field, and is made of D-ZLAF67, which is a common aspheric lens material, and has the advantages of high thermal resistance, high transmittance for light, and the like. The sixth lens includes a seventh object end surface S71 and a seventh image end surface S72 corresponding to a seventh receiving surface and a seventh emitting surface, respectively, of the object plane emitted light. Meanwhile, the aspheric lens is used as the last lens of the micro-objective and is mainly used for overall aberration correction.

The first object end surface S11 is planar to facilitate direct contact with tissue. The first image end surface S12, the second image end surface S22, the third object end surface S31, the fourth object end surface S41, the fourth image end surface S42, the fifth object end surface S51, the sixth image end surface S62, and the seventh object end surface S71 are convex. The second object end surface S21, the third image end surface S32, the fifth image end surface S52, the sixth object end surface S61, and the seventh image end surface S72 are all concave surfaces.

Namely, the large-field micro microscope objective satisfies the following conditional expression:

(1)R1F＞0，R1R＜0；

(2)R2F＜R2R＜0；

(3)R3F＞R3R＞0；

(4)R4F＞0，R4R＜0；

(5)R5F＞R5R＞0；

(6)R6F＜R6R＜0；

(7)R7F＞R7R＞0；

wherein R1F is a radius of curvature of the first object end surface S11 of the first lens 10; R1R is the radius of curvature of the first image end surface S12 of the first lens 10; R2F is the radius of curvature of the second end surface S21 of the second lens 20; R2R is the radius of curvature of the second image end surface S22 of the second lens 20; R3F is the radius of curvature of the third object-end surface S31 of the lens 30; R3R is the radius of curvature of the third image end surface S32 of the lens 30; R4F is the radius of curvature of the fourth object-end surface S41 of the lens 40; R4R is the radius of curvature of the fourth image end surface S42 of the lens 40; R5F is a radius of curvature of the fifth object end surface S51 of the fourth lens 50; R5R is a radius of curvature of the fifth image end surface S52 of the fourth lens 50; R6F is a radius of curvature of the sixth object end surface S61 of the fifth lens 60; R6R is a radius of curvature of the sixth image end surface S62 of the fifth lens 60; R7F is a radius of curvature of the seventh object end surface S71 of the sixth lens 70; R7R is a radius of curvature of the seventh image end surface S72 of the sixth lens 70.

The micro-objective with an outer diameter of 2.6mm is shown in Table 1, wherein a represents an aspherical surface. The following were used: specific parameters of micro microscope objective with outer diameter of 2.6mm

TABLE 1

The aspheric coefficients of the aspheric lens are shown in table 2, where the conic coefficient of aspheric surface 12 is-0.546, with no other aspheric coefficients. The aspherical surface coefficient of the aspherical surface 13 is as follows:

TABLE 2

FIG. 2 is a plot of image space points showing the diffuse speckle patterns and root mean square dimensions at twelve different positions of image space center, 69 μm, 138 μm, 208 μm, 278 μm, 349 μm, 418 μm, 485 μm, 550 μm, 581 μm, 591 μm and 620 μm. The radius of the Airy spots is 1.272 mu m, the root-mean-square size of the diffuse spots of all the fields is close to the size of the Airy spots, and the design can be considered to reach the approximate diffraction limit. The root-mean-square size of the scattered spots in all fields is smaller than 4 mu m, namely, the root-mean-square size of the scattered spots is smaller than the diameter of a single optical fiber of the optical fiber bundle, and the requirements of the micro microscope objective are met.

Fig. 3 is an optical path difference curve of the large-field micro-objective lens at twelve fields in the radial direction of an image. The optical path difference curve represents the difference between the optical path of the light and the optical path of the chief ray. The two graphs of each view field respectively represent a meridian plane and a sagittal plane, and the abscissa is a normalized entrance pupil coordinate. Ideally, the optical path difference value should be 0, i.e. the curve coincides with the abscissa axis. However, the optical path difference curve shows a different state due to the existence of aberration. In the design, the maximum curve optical path difference corresponding to the wavelength of 550nm can reach 1.86 lambda at the pupil edge. However, the root mean square value of the wave front aberration corresponding to the design is 0.04 lambda and less than 0.25 lambda, and the micro microscope objective lens can be considered to be approximate to the diffraction limit.

Fig. 4 shows the image field curvature and distortion curve of the large-field micro-objective, from which three aberrations of the design can be analyzed: field curvature, astigmatism and distortion. From the field curvature curve, the maximum value of field curvature was 9.03 μm and the maximum value of astigmatism was 10.53 μm for the three wavelengths. The maximum value of field curvature converted to the object space is 2.74 μm, and the maximum value of astigmatism is 3.19 μm, which is smaller than the axial resolution of the fluorescence confocal endoscope. In the distortion curve, the maximum distortion value is 1.25%, which is smaller than the distortion distinguishable by human eyes, and the imaging is not influenced. The field curvature and distortion diagram of fig. 4 illustrates that the design corrects for field curvature, astigmatism and distortion very well.

FIG. 5 shows the MTF curve and chromatic aberration focus-shift curve of the large-field micro-objective. Wherein, the graph (a) is the MTF curves of the meridian plane and the sagittal plane of twelve different positions, and the MTF curves under the diffraction limit condition are given for comparison. The 24 MTF curves have a certain difference with the MTF curves under the diffraction limit condition, and the MTFs at 128lp/mm are all larger than 0.6 and meet the design index larger than 0.5. In the chromatic aberration focal shift curve of the graph (b), the maximum chromatic aberration focal shift is 14.52 μm, the maximum object focus displacement is 4.4 μm, which is smaller than the axial resolution of the confocal system, so that the chromatic aberration can be considered to be well corrected by the design.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.