Endoscope optical system and endoscope

Abstract

The application discloses an endoscope optical system and an endoscope, and the endoscope optical system comprises a first fixed lens group, a first movable lens group, a second movable lens group and a second fixed lens group arranged in sequence along an optical axis from an incident surface to an image surface, during magnification adjustment, the relative positions of an imaging object, the first fixed lens group, the second fixed lens group and the image surface remain constant, the first movable lens group and the second movable lens group are synchronously and reversely moved to compensate for optical path changes during zooming, the imaging focus is stable during continuous magnification adjustment, and the total optical path length of the optical system remains constant. The optical path length remains constant during magnification adjustment, the focus drift is avoided, the object distance does not need to be adjusted during the whole magnification process, doctors can quickly switch to the required magnification, from large-scale screening to fine tissue examination, the operation is smooth and accurate, and clearer lesion image observation conditions are provided for doctors.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of endoscopes, in particular to an endoscope optical system and an endoscope. BACKGROUND

[0002] An endoscope is an important device for medical examination and surgery, and is widely used in the fields of gastroscopes, bronchoscopes and cystoscopes. The development trend of modern endoscope technology is to provide higher resolution, wider field of view and higher magnification images, so that doctors can accurately observe subtle lesions or complex anatomical structures. However, the traditional endoscope optical system has some problems in the adjustment of magnification and the maintenance of image quality, which brings great inconvenience to the operation of doctors, as follows:

[0003] If the observation of subtle lesions is realized by relying on electronic magnification, this method inevitably loses image quality and has loss of clarity and details.

[0004] If the adjustment of magnification is realized by adjusting the distance between the entire optical system and the imaging object (object distance), as the magnification increases, the object distance will correspondingly decrease, which increases the complexity of operation and makes it difficult to ensure the convenience of use and the consistency of imaging quality. Moreover, due to the limited moving range of the lens group, this design has limitations in the magnification range, imaging quality and system aplanatic characteristics.

[0005] In addition, during the adjustment of the object distance to adjust the magnification, imaging jitter or loss of field of view, and focus drift may also occur, which requires re-focusing (i.e. secondary focusing), which will lead to a decrease in operation efficiency and increase the burden of the user on the system operation.

[0006] Therefore, the current endoscope still needs to be improved, which limits the development and popularization of high-resolution medical imaging technology of endoscopes. SUMMARY

[0007] To solve the problems of complex magnification adjustment process and focus drift in the imaging of existing endoscopes, the purpose of the present application is to provide an endoscope optical system and an endoscope which do not need to adjust the object distance during the magnification process, improve the operation efficiency and reduce the operation burden of doctors.

[0008] To achieve the above-mentioned application purpose, an embodiment of the present application provides an endoscope optical system, comprising, arranged in order along the optical axis from the incident surface to the image surface:

[0009] a first fixed lens group for preliminarily converging incident light;

[0010] a first movable lens group, which is a movable concave lens group, for adjusting the focal length of the optical system by moving;

[0011] The second mobile lens group is a mobile convex lens group, which is used to compensate the focus change caused by the movement of the second lens group;

[0012] The second fixed lens group is used to focus the light to the image plane;

[0013] During the adjustment of the magnification, the relative positions of the imaging object, the first fixed lens group, the second fixed lens group and the image plane remain constant, and the first mobile lens group and the second mobile lens group are synchronously and reversely moved to compensate the change of the optical path during the zooming, so that the imaging focus is stable during the continuous adjustment of the magnification, and the total optical path length of the optical system remains constant.

[0014] As a further improvement of the present application, the first fixed lens group has a positive refractive power, the first mobile lens group has a negative refractive power, the second mobile lens group has a positive refractive power, and the second fixed lens group has a positive refractive power.

[0015] As a further improvement of the present application, the endoscope optical system further comprises a third fixed lens group arranged between the first mobile lens group and the second mobile lens group, and the third fixed lens group has a negative refractive power.

[0016] As a further improvement of the present application, the focal length of the lens satisfies the following conditions:

[0017] The focal length fa of the first fixed lens group: 4mm<fa<8mm;

[0018] The focal length fb of the first mobile lens group: -7.0mm<fb<-6.5mm;

[0019] The focal length fc of the third fixed lens group: -7.8mm<fc<-7.3mm;

[0020] The focal length fd of the second mobile lens group: 5.2mm<fd<5.7mm;

[0021] The focal length fe of the second fixed lens group: 2mm<fe<5mm.

[0022] As a further improvement of the present application, the first fixed lens group comprises:

[0023] The first single lens L1 is a plano-concave lens, and the focal length f1 is: -1.5mm<f1<-1.0mm;

[0024] The first filter F1 is an afocal single lens;

[0025] The second single lens L2 is an aspheric lens, and the focal length f2 is: 3.2mm<f2<4.2mm;

[0026] The third doublet lens L3 is a double convex lens with a focal length f3: 11.2mm < f3 < 12.2mm, and comprises:

[0027] The first lens L3.1 is a meniscus lens with a focal length f3.1: -0.79 < f3.1 / f3 < -0.74;

[0028] The second lens L3.2 is a double convex lens with a focal length f3.2: 0.42 < f3.2 / f3 < 0.48.

[0029] As a further improvement of the present application, the first moving lens group comprises: a fourth doublet lens L4 which is a double concave lens with a focal length f4: -7.0mm < f4 < -6.5mm, and comprises:

[0030] The first lens L4.1 is a meniscus lens with a focal length f4.1: -1.27 < f4.1 / f4 < -1.21;

[0031] The second lens L4.2 is a double concave lens with a focal length f4.2: 3.81 < f4.2 / f4 < 3.87.

[0032] As a further improvement of the present application, the third fixed lens group comprises: a fifth single lens L5 which is a double concave lens with a focal length f5: -7.8mm < f5 < -7.3mm.

[0033] As a further improvement of the present application, the second moving lens group comprises:

[0034] The sixth doublet lens L6 is a double convex lens with a focal length f6: 5.2mm < f6 < 5.7mm, and comprises:

[0035] The first lens L6.1 is a double convex lens with a focal length f6.1: 0.46 < f6.1 / f6 < 0.52;

[0036] The second lens L6.2 is a meniscus lens with a focal length f6.2: -1.06 < f6.2 / f6 < -1.01.

[0037] As a further improvement of the present application, the second fixed lens group comprises:

[0038] The seventh doublet lens L7 is a meniscus lens with a focal length f7: -15.4mm < f7 < -14.4mm, and comprises:

[0039] The first lens L7.1 is a double convex lens with a focal length f7.1: -0.26 < f7.1 / f7 < -0.20;

[0040] The second lens L7.2 is a double-concave lens, and a focal length f7.2 satisfies 0.18 < f7.2 / f7 < 0.22;

[0041] The eighth doublet lens L8 is a double-convex lens, and a focal length f8 satisfies 3.9 mm < f8 < 4.5 mm, and the eighth doublet lens L8 comprises:

[0042] The first lens L8.1 is a double-convex lens, and a focal length f8.1 satisfies 0.51 < f8.1 / f8 < 0.56;

[0043] The second lens L8.2 is a meniscus lens, and a focal length f8.2 satisfies -1.38 < f8.2 / f8 < -1.33;

[0044] The ninth doublet lens L9 is a double-convex lens, and a focal length f9 satisfies 6.8 mm < f9 < 7.3 mm, and the ninth doublet lens L9 comprises:

[0045] The first lens L9.1 is a double-convex lens, and a focal length f9.1 satisfies 0.36 < f9.1 / f9 < 0.40;

[0046] The second lens L9.2 is a meniscus lens, and a focal length f9.2 satisfies -0.49 < f9.2 / f9 < -0.45;

[0047] The tenth single lens L10 is a double-concave lens, and a focal length f10 satisfies -2.7 mm < f10 < -2.2 mm;

[0048] The second filter F2 is an afocal single lens.

[0049] To achieve one of the above-mentioned purposes, an embodiment of the present application provides an endoscope, which comprises the endoscope optical system described above, and an electronic imaging module and a control device connected thereto.

[0050] Compared with the prior art, the endoscope optical system has the following beneficial effects: the synchronous reverse movement design of the first moving lens group and the second moving lens group keeps the optical path length constant when the magnification is adjusted, avoids focal point drift, realizes seamless switching from wide-angle observation to high-magnification zooming, and the entire zooming process does not need to adjust the object distance, so that the system always remains parfocal, thereby improving the operation efficiency and reducing the operation burden of the doctor. The continuous adjustable magnification enables the doctor to quickly switch to the required magnification, from large-scale screening to fine tissue examination, smooth and accurate operation, and provides the doctor with clearer lesion image observation conditions. The endoscope optical system realizes comprehensive improvement in performance and structure in the field of optical zoom endoscopes. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1is a structural schematic diagram of an endoscope optical system according to an embodiment of the present application;

[0052] Figure 2 is a size symbol schematic diagram of an endoscope optical system according to an embodiment of the present application;

[0053] Figure 3 is a schematic diagram of continuous magnification adjustment of an endoscope optical system according to an embodiment of the present application;

[0054] Figure 4 is a numerical relationship diagram of synchronous reverse movement of the first and second movable lens groups according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] The present application will be described in detail below with reference to the specific embodiments shown in the drawings. However, these embodiments do not limit the present application, and the structural, method, or functional changes made by those of ordinary skill in the art based on these embodiments are included in the protection scope of the present application.

[0056] It should be understood that the terms such as "upper", "above", "lower", "below", and the like used herein to indicate spatial relative positions are for the purpose of facilitating description to describe the relationship of one unit or feature relative to another unit or feature as shown in the drawings. The spatial relative position terms can be intended to include different orientations of the device in use or operation other than the orientation shown in the drawings.

[0057] An embodiment of the present application provides an endoscope optical system and an endoscope which do not need to adjust the object distance during the magnification process, improve the operation efficiency, and reduce the operation burden of doctors.

[0058] An endoscope optical system according to an embodiment of the present application includes a first fixed lens group, a first movable lens group, a second movable lens group, and a second fixed lens group arranged in sequence along the optical axis from the entrance surface to the image surface. The arrangement is compact, the optical path layout is optimized, and the actual application requirements of the endoscope are met.

[0059] The first fixed lens group is located at the front end of the optical system and is used to preliminarily converge the incident light reflected from the imaged object. The first fixed lens group is designed to have a positive refractive power to provide a preliminary convergence effect for the entire system.

[0060] The first movable lens group is designed as a movable concave lens group with a negative refractive power. By changing the relative position between the first movable lens group and other lens groups, the overall focal length of the optical system is adjusted, thereby realizing the adjustment of the magnification.

[0061] The second movable lens group is a movable convex lens group designed to have a positive refractive power. It is used to compensate for the change of the focal point caused by the movement of the first movable lens group, so as to ensure that the light is always accurately focused on the image surface.

[0062] The second fixed lens group is used to further converge and correct the light rays, and finally focus them to the image plane to provide a clear high-resolution image output.

[0063] During the adjustment of the magnification, the relative positions of the imaging object, the first fixed lens group, the second fixed lens group, and the image plane remain constant, and the first moving lens group and the second moving lens group are synchronously and reversely moved to compensate for the change in the optical path during zooming, so that the imaging focus is stable during continuous adjustment of the magnification, and the total optical path length of the optical system remains constant.

[0064] As shown in FIG. 1, when the first moving lens group moves toward the image side to increase the magnification of the system, the second moving lens group simultaneously moves toward the object side to compensate for the change in the optical path and maintain the total optical path length of the system constant. Figure 3 The total optical path length of the optical system includes the object distance + the image distance + the lens group spacing within the optical system, and the sum of D0, D1, …, D12 below is the total optical path length of the optical system. The constant total optical path length means that during continuous adjustment of the magnification of the endoscope optical system, the distance of the endoscope optical system to the object side is unchanged, the imaging distance is unchanged, and only the movement of the lenses within the endoscope optical system occurs, thereby maintaining the focal position of the imaging plane unchanged.

[0065] The distance and rate of synchronous and reverse movement are precisely designed and optimized to ensure that the total optical path in the light ray propagation path is unchanged, thereby realizing the parfocal characteristic. The parfocal characteristic enables the system to adjust the magnification without the need for secondary focusing, and the imaging focus is always stable on the image plane, greatly improving the use efficiency and the continuity of the image. The complexity of operation caused by adjusting the object distance in the traditional endoscope is eliminated, and the use burden of the doctor is reduced.

[0066] The endoscope optical system of the embodiment supports continuous adjustment of the magnification, and the magnification adjustment range can reach 1:6. In the wide-angle mode (lower magnification), the doctor can quickly complete a large range of lesion screening while maintaining the high resolution and low distortion characteristics of the imaging. In the detail observation mode (higher magnification), the system provides a clear local image of the lesion through optical magnification to help the doctor observe the subtle anatomical structure or lesion characteristics. The continuously adjustable magnification improves the diagnosis efficiency, enabling the doctor to quickly adapt to different observation needs, avoids the loss of image quality caused by electronic magnification, and improves the accuracy of diagnosis.

[0067] The endoscope optical system of the embodiment is designed for the visible light wavelength band of 415 nm to 675 nm, providing the doctor with clearer and more accurate lesion observation images, reducing the risk of misdiagnosis and missed diagnosis.

[0068] The endoscope optical system of the embodiment is designed for the visible light wavelength band of 415 nm to 675 nm, providing the doctor with clearer and more accurate lesion observation images, reducing the risk of misdiagnosis and missed diagnosis.

[0069] The endoscope optical system of the embodiment takes an innovative lens group design and movement mechanism as the core, not only meets the needs of high resolution, high magnification and parfocal characteristics of medical endoscopes, but also significantly improves the operation convenience and diagnosis efficiency of doctors, providing reliable technical support for the popularization and application of optical magnification endoscopes in the medical field.

[0070] The first fixed lens group has positive refractive power, the first moving lens group has negative refractive power, the second moving lens group has positive refractive power, and the second fixed lens group has positive refractive power.

[0071] The first fixed lens group preliminarily converges light from the object through positive refractive power, so that the light has higher optical efficiency when entering the first moving lens group. The first moving lens group has negative refractive power, and adjusts the optical path dynamically by diverging light, thereby adjusting the system focal length and providing a basis for subsequent magnification changes. The second moving lens group converges light through positive refractive power, compensates for the change of the optical path when the first moving lens group moves, and ensures the stability of the focal point. The positive refractive power of the second fixed lens group further converges light, accurately focuses it on the image plane, and completes high-resolution imaging. In this way, the endoscope optical system of the embodiment can maintain imaging quality in a larger magnification range, while ensuring the stability of the optical path, and provides doctors with clear and distortion-free images.

[0072] Further, the endoscope optical system further comprises a third fixed lens group arranged between the first moving lens group and the second moving lens group, and the third fixed lens group has negative refractive power.

[0073] When the first moving lens group adjusts the focal length, the third fixed lens group can compensate for the optical distortion that may be caused by the change of the optical path, so that the subsequent lens group can efficiently converge light to the image plane. In addition, the third fixed lens group can also help to expand the magnification range, which is especially effective in high magnification observation mode, ensuring the uniformity of light distribution during detail imaging, further optimizing the optical performance of the system, and improving the imaging stability and clarity. Especially in the process of dynamically adjusting the magnification, it can effectively eliminate the imaging error in the high magnification mode.

[0074] Further, the focal length of the lens satisfies the following conditions:

[0075] The focal length fa of the first fixed lens group: 4mm < fa < 8mm;

[0076] The focal length fb of the first moving lens group: -7.0mm < fb < -6.5mm;

[0077] The focal length fc of the third fixed lens group: -7.8mm < fc < -7.3mm;

[0078] The focal length fd of the second mobile lens group: 5.2mm < fd < 5.7mm;

[0079] The focal length fe of the second fixed lens group: 2mm < fe < 5mm.

[0080] The endoscope optical system with the above-mentioned focal length range ensures that the system can maintain high-resolution imaging during continuous adjustment of the magnification, while reducing the aberration and distortion problems in dynamic magnification. Whether in large-scale screening or subtle lesion observation, the system can quickly adapt and provide consistent high-quality images.

[0081] The design of the specific values of the present embodiment is based on the following specifications: field of view angle: 120°, effective F number: 8.0, focal length: 0.99mm, zoom ratio 1:6, image height: 0.97mm.

[0082] The specific dimensions of the endoscope optical system will be described below in combination with Figure 1 , 2 , and the specific numerical values corresponding to the symbols in Table 1.

[0083] Specifically, as shown in Figure 1 and 2 , the first fixed lens group comprises:

[0084] The first single lens L1 is a plano-concave lens, and the focal length f1 is -1.5mm < f1 < -1.0mm. The thickness of the first single lens L1 is CT1. The front surface of the first single lens L1 is a plane, and the rear surface has a radius R2. In addition, the design surface of the endoscope optical system is located in front of the center of the front surface of the first single lens L1 with a distance D0.

[0085] The first filter F1 is an afocal single lens, which does not change the optical path characteristics of the optical system, and can filter unnecessary spectrum to improve image contrast and quality. The thickness of the first filter F1 is CTF1, and the first filter F1 follows the first single lens L1 with an air gap D1. The front and rear surfaces R3 and R4 of the first filter F1 are planes.

[0086] The second single lens L2 is an aspheric lens, and the focal length f2 is 3.2mm < f2 < 4.2mm. The second single lens L2 corrects the aberration in the initial optical path, significantly reduces the spherical aberration and other high-order aberration problems of the system through the surface curvature and optimized design. The thickness of the second single lens L2 is CT2, and the second single lens L2 follows the first filter F1 with an air gap D2. The front surface radius R5 of the second single lens L2 is an aspheric surface, and the rear surface has a radius R6, a conic coefficient k, and high-order coefficients A4, A6, and A8.

[0087] The third doublet lens L3 is a biconvex lens with a focal length f3: 11.2mm < f3 < 12.2mm, and a thickness CT3 of the third doublet lens L3 is followed by the second single lens L2 with an air gap D3.

[0088] The third doublet lens L3 comprises:

[0089] The first lens L3.1 is a meniscus lens with a thickness CT3.1, a focal length f3.1: -0.79 < f3.1 / f3 < -0.74, a front surface radius R7 and a back surface radius R8.

[0090] The second lens L3.2 is a biconvex lens with a thickness CT3.2, a focal length f3.2: 0.42 < f3.2 / f3 < 0.48, a front surface radius R9 and a back surface radius R10.

[0091] The combined design of the first lens L3.1 and the second lens L3.2 optimizes the converging effect of the initial light rays while reducing chromatic aberration in the optical path.

[0092] The first fixed lens group provides a clear initial imaging path for the entire optical system, ensuring the imaging quality before magnification adjustment.

[0093] As shown in Table 1, the first moving lens group comprises: Figure 1 、 2 and Table 1, the fourth doublet lens L4 is a biconcave lens with a thickness CT4, a focal length f4: -7.0mm < f4 < -6.5mm, and the fourth doublet lens L4 is followed by the third doublet lens L3 with an air gap D4, the fourth doublet lens L4 comprises:

[0094] The first lens L4.1 is a meniscus lens with a thickness CT4.1, a focal length f4.1: -1.27 < f4.1 / f4 < -1.21, a front surface radius R11 and a back surface radius R12. The negative refractive power of the first lens L4.1 performs preliminary dynamic adjustment on the optical path through divergence, and the ratio of the design focal length f4.1 to the focal length f4 of the entire lens group is precisely optimized to ensure that the system does not introduce additional aberrations during dynamic adjustment of the optical path.

[0095] The second lens L4.2 is a biconcave lens with a thickness CT4.2, a focal length f4.2: 3.81 < f4.2 / f4 < 3.87, a front surface radius R13 and a back surface radius R14. The second lens L4.2 enhances the flexibility of dynamic adjustment, and through its divergent characteristics of light rays, it expands the magnification range of the system.

[0096] The stop STOP is followed by the fourth doublet lens L4 with an air gap D5.

[0097] As shown in Table 1, the first moving lens group comprises: Figure 1 ,2 and Table 1, the third fixed lens group includes: a fifth single lens L5, which is a double-concave lens, has a focal length f5: -7.8mm < f5 < -7.3mm, and a thickness CT5 of the fifth single lens L5 is spaced apart from a stop STOP by an air gap D6, and the fifth single lens L5 has a front surface R15 and a rear surface R16. The third fixed lens group is arranged between the first moving lens group and the second moving lens group, and compensates and balances the dynamic optical path by using the negative refractive power. The double-concave lens structure of the fifth single lens L5 can adjust the ratio of converging light and diverging light, so as to ensure that the system does not introduce obvious distortion when adjusting the magnification, effectively reduces the aberration and field distortion caused by dynamic magnification during detail observation in the high magnification mode, and at the same time maintains the overall imaging clarity of the system.

[0098] As Figure 1 , 2 and Table 1, the second moving lens group includes:

[0099] A sixth double cemented lens L6, which is a double-convex lens, has a focal length f6: 5.2mm < f6 < 5.7mm, and a thickness CT6 of the sixth double cemented lens L6 is spaced apart from the fifth single lens L5 by an air gap D7, and the sixth double cemented lens L6 includes:

[0100] A first lens L6.1, which is a double-convex lens, has a focal length f6.1: 0.46 < f6.1 / f6 < 0.52, a front surface radius R17 and a rear surface radius R18. The positive refractive power of the first lens L6.1 preliminarily adjusts the convergence of the optical path, and the focal length range and design ratio thereof are matched with the optical parameters of the entire lens group, so as to realize stable convergence of light rays during dynamic magnification.

[0101] A second lens L6.2, which is a meniscus lens, has a focal length f6.2: -1.06 < f6.2 / f6 < -1.01, a front surface radius R19 and a rear surface radius R20. The negative refractive power of the second lens L6.2 compensates and balances the converging effect of the first lens L6.1, and reduces the problems of aberration and high-order optical distortion.

[0102] The first moving lens group functions to change the focusing mode of light rays by dispersing the light rays. During zooming, the fourth double cemented lens L4 acts as a focusing lens, which is responsible for adjusting the focal position of imaging by changing the focal length. Because a concave lens scatters light rays, it is usually used to change the relationship between the object distance and the imaging distance, so as to realize magnification or reduction. The purpose of focusing is to keep the focal point of the system on the photosensitive surface of the sensor at all times, so as to ensure image clarity. The imaging position is adjusted by changing the focal length.

[0103] The second moving lens group is responsible for adjusting the overall imaging effect of the system by compensation when the fourth doublet lens L4 changes the focal length, ensuring the stability of the focal point position and avoiding image blur caused by the focusing of the fourth doublet lens L4. The compensation process of the sixth doublet lens L6, which is a biconvex lens, offsets the focal length change caused by the fourth doublet lens L4, so that the focal point does not shift during the entire zooming process, thereby realizing the parfocal state.

[0104] The synchronous reverse movement of the first moving lens group and the second moving lens group keeps the optical path length constant during dynamic adjustment of the magnification, ensuring the parfocal characteristic, and provides higher imaging resolution and clarity through optical optimization.

[0105] Continuing as shown in Figure 1 、 2 and Table 1, the second fixed lens group includes:

[0106] The seventh doublet lens L7 is a meniscus lens with a focal length f7: -15.4mm < f7 < -14.4mm, and the thickness CT7 of the seventh doublet lens L7 is followed by the sixth doublet lens L6 with an air gap D8. The seventh doublet lens L7 can reduce the divergence offset of light, and the seventh doublet lens L7 includes:

[0107] The first lens L7.1 has a thickness CT7.1 and is a biconvex lens with a focal length f7.1: -0.26 < f7.1 / f7 < -0.20, a front surface radius R21 and a back surface radius R22.

[0108] The second lens L7.2 has a thickness CT7.2 and is a biconcave lens with a focal length f7.2: 0.18 < f7.2 / f7 < 0.22, a front surface radius R23 and a back surface radius R24.

[0109] The eighth doublet lens L8 is a biconvex lens with a focal length f8: 3.9mm < f8 < 4.5mm, and the eighth doublet lens L8 realizes imaging distortion correction at high magnification. The thickness CT8 of the eighth doublet lens L8 is followed by the seventh doublet lens L7 with an air gap D9, and the eighth doublet lens L8 includes:

[0110] The first lens L8.1 has a thickness CT8.1 and is a biconvex lens with a focal length f8.1: 0.51 < f8.1 / f8 < 0.56, a front surface radius R25 and a back surface radius R26.

[0111] The second lens L8.2 has a thickness CT8.2 and is a meniscus lens with a focal length f8.2: -1.38 < f8.2 / f8 < -1.33, a front surface radius R27 and a back surface radius R28.

[0112] A ninth doublet lens L9, which is a double convex lens, has a focal length f9: 6.8mm < f9 < 7.3mm, and supports high resolution imaging, and a thickness CT9 of the ninth doublet lens L9 is spaced apart from the eighth doublet lens L8 by an air gap D10, and the ninth doublet lens L9 includes:

[0113] A first lens L9.1 has a thickness CT9.1, is a double convex lens, has a focal length f9.1: 0.36 < f9.1 / f9 < 0.40, and has a front surface that is an aspheric surface, a conic constant k, and higher order coefficients A4, A6, A8, and a back surface radius R30.

[0114] A second lens L9.2 has a thickness CT9.2, is a meniscus lens, has a focal length f9.2: -0.49 < f9.2 / f9 < -0.45, and has a front surface radius R31 and a back surface radius R32.

[0115] A tenth single lens L10, which is a double concave lens, has a thickness CT10 spaced apart from the ninth doublet lens L9 by an air gap D11, has a focal length f10: -2.7mm < f10 < -2.2mm, and has a front surface R33 and a back surface R34.

[0116] A second filter F2, which is an afocal single lens, is a protective glass for an image sensor, and is spaced apart from the tenth single lens L10 by an air gap D12.

[0117] The tenth single lens L10 and the second filter F2 further enhance the spectral range and anti-reflection performance of the system, and particularly in the visible light band (415nm ~ 675nm), the contrast and the resolution of the imaging are significantly improved.

[0118] The radii of curvature of the optical lenses L1 ~ L10, the thicknesses thereof, and the air gaps D therebetween are shown in Table 1 below.

[0119]

[0120]

[0121]

[0122] Table 1

[0123] In the aspheric surface, the conic constant k and the higher order coefficients A4, A6, A8 satisfying the aspheric surface shape are shown in Table 2. The aspheric surface is expressed by the following equation:

[0124]

[0125] k A2 A4 A6 A8 R6 0.756 - 5.375E-07 8.237E-09 4.534E-11 R29 -0.45 - 1.53E-06 -7.837E-08 -

[0126] Table 2

[0127] In addition, the process of synchronous reverse movement of the first mobile lens group and the second mobile lens group is described, wherein the fourth double cemented lens L4 of the first mobile lens group is taken as the mobile group one, the sixth double cemented lens L6 of the second mobile lens group is taken as the mobile group two, and other lenses are relatively static. The position changes of the mobile group one and the mobile group two will cause the changes of D4, D5, D7 and D8. In the whole zooming process, D4+D5 and D7+D8 remain constant. The numerical relationship diagram of the movement amount is shown in the following table 2. Figure 4 The specific values are shown in the following table 3.

[0128] Mobile Group 2 Mobile Group 1 1 12.62 0.47 1.2 12.43 1.48 1.4 12.13 2.46 1.8 11.76 3.45 2.5 11.35 4.4 3.5 10.77 5.15 4.4 10.1 5.68 5.2 9.44 5.95 6 8.67 6.1

[0129] Table 3

[0130] In addition, the embodiment also provides an endoscope, which comprises the endoscope optical system and an electronic imaging module and a control device connected thereto.

[0131] The electronic imaging module comprises an image sensor, and the image plane of the endoscope optical system is directly connected to the image sensor, such as a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) imaging module. The endoscope optical system is responsible for accurately focusing the optical image on the image sensor. The image sensor converts the received optical image into an electrical signal and performs digital processing through a subsequent processing module. The image sensor is closely arranged on the image plane of the optical system to minimize signal loss or distortion that may occur during optical signal transmission, ensuring that the clarity and resolution of the final image reach medical standards.

[0132] The endoscope optical system is integrated in a soft control device, and the control device comprises:

[0133] The insertion part is designed as a flexible structure with a small diameter, which can freely bend in a complex cavity to meet the needs of surgery. The front end of the insertion part is provided with an endoscope optical system and an electronic imaging module for obtaining high-resolution images of the lesion.

[0134] The bending part connects the insertion part and the front end part, and by operating the bending operation knob on the handle, the bending part can direct the field of view of the endoscope optical system to the target position.

[0135] The operation part includes a control handle, an image output interface and an operation knob. The doctor can adjust the magnification, field of view direction and image output of the optical system through the control handle.

[0136] The imaging signal transmission module: the image signal is transmitted from the image sensor to the operation part, which can be transmitted to the external display device through optical fiber, cable or wireless mode to realize real-time monitoring.

[0137] The endoscope of the embodiment has flexibility and operability in clinical operation, and the application of the soft component can significantly improve the adaptability of the endoscope in the complex cavity of the human body.

[0138] The endoscope realizes the perfect balance of miniaturization, high resolution and flexible operation by the close combination of the endoscope optical system, the electronic imaging module and the control device. The endoscope has flexibility and operability in clinical operation, and can significantly improve the parfocal shooting, high-resolution imaging and dynamic magnification adjustment of the endoscope in the complex cavity of the human body, thereby providing new technical support for modern medical diagnosis and treatment.

[0139] Compared with the common technology, the embodiment has the following beneficial effects:

[0140] The endoscope optical system is designed by synchronous reverse movement of the first moving lens group and the second moving lens group, the optical path length remains constant when adjusting the magnification, the focal drift is avoided, the seamless switching from wide-angle observation to high magnification is realized, the object distance does not need to be adjusted during the entire magnification process, the system always maintains the parfocal state, thereby improving the operation efficiency and reducing the operation burden of the doctor. The magnification is continuously adjustable, so that the doctor can quickly switch to the required magnification, from large-scale screening to fine tissue examination, the operation is smooth and accurate, and the doctor is provided with clearer lesion image observation conditions. The endoscope optical system realizes the overall improvement of performance and structure in the field of optical magnification endoscopes.

[0141] It should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and the skilled person should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by the skilled person.

[0142] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present application, and are not used to limit the protection scope of the present application. Any equivalent embodiments or changes made without departing from the spirit of the present application should be included in the protection scope of the present application.

Claims

1. An endoscope optical system characterized by comprising: Comprise, in order along the optical axis from the entrance surface to the image surface: A first fixed lens group for preliminarily converging incident light rays, the first fixed lens group having a positive refractive power; A first movable lens group, which is a movable concave lens group for adjusting the focal length of the optical system by moving, the first movable lens group having a negative refractive power, the first movable lens group comprising a fourth doublet lens L4, which is a double concave lens; A second movable lens group, which is a movable convex lens group for compensating for the focal point change caused by the movement of the second lens group, the second movable lens group having a positive refractive power, the second movable lens group comprising a sixth doublet lens L6, which is a double convex lens; A second fixed lens group for focusing light rays to the image surface, the second fixed lens group having a positive refractive power; A third fixed lens group disposed between the first movable lens group and the second movable lens group, the third fixed lens group having a negative refractive power; During the process of adjusting the magnification, the relative positions of the imaging object, the first fixed lens group, the second fixed lens group and the image surface remain constant, and the first movable lens group and the second movable lens group move synchronously and reversely to compensate for the change in the optical path during the zooming process, so that the imaging focal point is stable during the continuous adjustment of the magnification, and the total optical path length of the optical system remains constant.

2. The endoscope optical system according to claim 1, characterized by, The focal length of the lens satisfies the following conditions: The focal length fa of the first fixed lens group: 4mm < fa < 8mm; The focal length fb of the first movable lens group: -7.0mm < fb < -6.5mm; The focal length fc of the third fixed lens group: -7.8mm < fc < -7.3mm; The focal length fd of the second movable lens group: 5.2mm < fd < 5.7mm; The focal length fe of the second fixed lens group: 2mm < fe < 5mm.

3. The endoscope optical system according to claim 2, characterized by, The first fixed lens group comprises: A first single lens L1, which is a plano-concave lens, having a focal length f1: -1.5mm < f1 < -1.0mm; A first filter F1, which is an afocal single lens; A second single lens L2, which is an aspherical lens, having a focal length f2: 3.2mm < f2 < 4.2mm; A third doublet lens L3, which is a double convex lens, having a focal length f3: 11.2mm < f3 < 12.2mm, the third doublet lens L3 comprising: A first lens L3.1, which is a meniscus lens, having a focal length f3.1: -0.79 < f3.1 / f3 < -0.74; A second lens L3.2, which is a double convex lens, having a focal length f3.2: 0.42 < f3.2 / f3 < 0.

48.

4. The endoscope optical system according to claim 2, characterized by, The fourth doublet lens L4 has a focal length f4: -7.0mm < f4 < -6.5mm, the fourth doublet lens L4 comprising: A first lens L4.1, which is a meniscus lens, having a focal length f4.1: -1.27 < f4.1 / f4 < -1.21; A second lens L4.2, which is a double concave lens, having a focal length f4.2: 3.81 < f4.2 / f4 < 3.

87.

5. The endoscope optical system according to claim 2, characterized by, The third fixed lens group includes a fifth single lens L5 which is a double-concave lens having a focal length f5 of -7.8mm < f5 < -7.3mm.

6. The endoscope optical system according to claim 2, characterized by, The sixth double cemented lens L6 has a focal length f6 of 5.2mm < f6 < 5.7mm, and includes: The first lens L6.1 is a double-convex lens having a focal length f6.1 of 0.46 < f6.1 / f6 < 0.52; The second lens L6.2 is a meniscus lens having a focal length f6.2 of -1.06 < f6.2 / f6 < -1.

01.

7. The endoscope optical system according to claim 2, characterized by, The second fixed lens group includes: The seventh double cemented lens L7 is a meniscus lens having a focal length f7 of -15.4mm < f7 < -14.4mm, and includes: The first lens L7.1 is a double-convex lens having a focal length f7.1 of -0.26 < f7.1 / f7 < -0.20; The second lens L7.2 is a double-concave lens having a focal length f7.2 of 0.18 < f7.2 / f7 < 0.22; The eighth double cemented lens L8 is a double-convex lens having a focal length f8 of 3.9mm < f8 < 4.5mm, and includes: The first lens L8.1 is a double-convex lens having a focal length f8.1 of 0.51 < f8.1 / f8 < 0.56; The second lens L8.2 is a meniscus lens having a focal length f8.2 of -1.38 < f8.2 / f8 < -1.33; The ninth double cemented lens L9 is a double-convex lens having a focal length f9 of 6.8mm < f9 < 7.3mm, and includes: The first lens L9.1 is a double-convex lens having a focal length f9.1 of 0.36 < f9.1 / f9 < 0.40; The second lens L9.2 is a meniscus lens having a focal length f9.2 of -0.49 < f9.2 / f9 < -0.45; The tenth single lens L10 is a double-concave lens having a focal length f10 of -2.7mm < f10 < -2.2mm. The second filter F2 is an afocal single lens.

8. An endoscope characterized by comprising: The endoscope includes the endoscope optical system according to any one of claims 1 to 7, and an electronic imaging module and a control device connected thereto.

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