Endoscope optical system and endoscope

Abstract

The invention 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 which are sequentially arranged from an incident plane to an image plane along an optical axis. The relative positions of an imaging object and the first fixed lens group, the second fixed lens group and the image surface are kept constant, and the first movable lens group and the second movable lens group synchronously and reversely move to compensate for the light path change in the zooming process, so that the imaging focus is stable in the amplification factor continuous adjustment process, and the total light path length of the optical system is kept constant. When the magnification is adjusted, the length of an optical path is kept constant, focus drift is avoided, an object distance does not need to be adjusted in the whole magnification process, a doctor can rapidly switch to the required magnification, fine tissue examination is screened from a large range, operation is smooth and accurate, and clearer focus image observation conditions are provided for the doctor.

Description

Technical Field

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

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

[0003] If electronic magnification is relied upon to observe subtle lesions, this approach will inevitably result in loss of image quality, resulting in loss of clarity and detail.

[0004] If the magnification is adjusted by adjusting the distance between the entire optical system and the imaging object (object distance), as the magnification increases, the object distance will decrease accordingly, which increases the complexity of the operation and makes it difficult to ensure the convenience of use and the consistency of the imaging quality. In addition, due to the limited range of movement of the lens group, this design has limitations in terms of magnification range, imaging quality and system parfocality.

[0005] In addition, in the process of adjusting the object distance and magnification, image jitter or loss of field of view and focus drift are prone to occur, all of which require refocusing (i.e., secondary focusing), which will lead to a decrease in operating efficiency and increase the user's burden on system operation.

[0006] Therefore, current endoscopes still need to be improved, which limits the development and promotion of endoscopic high-resolution medical imaging technology. Summary of the invention

[0007] In order to solve the problems of complex magnification adjustment process and focus drift in existing endoscopic imaging, the purpose of the present invention is to provide an endoscopic optical system and endoscope that does not require adjustment of object distance during the magnification process, improves operating efficiency and reduces the operating burden of doctors.

[0008] To achieve the above-mentioned object of the invention, one embodiment of the present invention provides an endoscope optical system, comprising:

[0009] A first fixed lens group, used for initially converging incident light;

[0010] The first movable lens group is a movable concave lens group, which is used to adjust the focal length of the optical system by moving;

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

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

[0013] During the process of adjusting the magnification, the relative positions of the imaging object and the first fixed lens group, the second fixed lens group and the image plane are kept constant, and the first movable lens group and the second movable lens group move synchronously in opposite directions to compensate for the changes in the optical path during the magnification change, so that the imaging focus is stable during the continuous adjustment of the magnification, and the total optical path length of the optical system is kept constant.

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

[0015] As a further improvement of the present invention, the endoscope optical system further includes a third fixed lens group disposed between the first movable lens group and the second movable lens group, and the third fixed lens group has a negative refractive power.

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

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

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

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

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

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

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

[0023] The first single lens L1 is a plano-concave lens with a focal length of -1.5 mm. <f1<-1.0mm;

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

[0025] The second single lens L2 is an aspherical lens with a focal length f2 of 3.2 mm. <f2<4.2mm;

[0026] The third doublet lens L3 is a biconvex lens, and its focal length f3 satisfies: 11.2mm < f3 < 12.2mm. The third doublet lens L3 includes:

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

[0028] The second lens L3.2 is a biconvex lens, and its focal length f3.2 satisfies: 0.42 < f3.2 / f3 < 0.48.

[0029] As a further improvement of the present invention, the first moving lens group includes: a fourth doublet lens L4, which is a biconcave lens, and its focal length f4 satisfies: -7.0mm < f4 < -6.5mm. The fourth doublet lens L4 includes:

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

[0031] The second lens L4.2 is a biconcave lens, and its focal length f4.2 satisfies: 3.81 < f4.2 / f4 < 3.87.

[0032] As a further improvement of the present invention, the third fixed lens group includes: a fifth singlet lens L5, which is a biconcave lens, and its focal length f5 satisfies: -7.8mm < f5 < -7.3mm.

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

[0034] A sixth doublet lens L6, which is a biconvex lens, and its focal length f6 satisfies: 5.2mm < f6 < 5.7mm. The sixth doublet lens L6 includes:

[0035] The first lens L6.1 is a biconvex lens, and its focal length f6.1 satisfies: 0.46 < f6.1 / f6 < 0.52;

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

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

[0038] A seventh doublet lens L7, which is a meniscus lens, and its focal length f7 satisfies: -15.4mm < f7 < -14.4mm. The seventh doublet lens L7 includes:

[0039] The first lens L7.1 is a biconvex lens, and its focal length f7.1 satisfies: -0.26 < f7.1 / f7 < -0.20;

[0040] The second lens L7.2 is a biconcave lens, and its focal length f7.2 satisfies: 0.18 < f7.2 / f7 < 0.22;

[0041] The eighth doublet lens L8 is a biconvex lens, and its focal length f8 satisfies: 3.9 mm < f8 < 4.5 mm. The eighth doublet lens L8 includes:

[0042] The first lens L8.1 is a biconvex lens, and its focal length f8.1 satisfies: 0.51 < f8.1 / f8 < 0.56;

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

[0044] The ninth doublet lens L9 is a biconvex lens, and its focal length f9 satisfies: 6.8 mm < f9 < 7.3 mm. The ninth doublet lens L9 includes:

[0045] The first lens L9.1 is a biconvex lens, and its focal length f9.1 satisfies: 0.36 < f9.1 / f9 < 0.40;

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

[0047] The tenth singlet lens L10 is a biconcave lens, and its focal length f10 satisfies: -2.7 mm < f10 < -2.2 mm;

[0048] The second filter F2 is a afocal singlet lens.

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

[0050] Compared with the prior art, the present invention has the following beneficial effects: Through the synchronous reverse movement design of the first moving lens group and the second moving lens group, the optical path length remains constant when adjusting the magnification, avoiding focus drift, realizing seamless switching from wide-angle observation to high-magnification zoom, and the object distance does not need to be adjusted during the entire zoom process, so that the system always maintains an afocal state, thereby improving the operation efficiency and reducing the operation burden on doctors. Moreover, the magnification is continuously adjustable, enabling doctors to quickly switch to the required magnification, from large-scale screening to microscopic tissue examination, with smooth and precise operation, providing doctors with clearer observation conditions for lesion images. The endoscope optical system has achieved a comprehensive improvement in performance and structure in the field of optical magnification endoscopes. Brief Description of the Drawings

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

[0052] Figure 2 is a schematic diagram of dimension symbols of an endoscope optical system according to an embodiment of the present invention;

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

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

[0055] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0056] It should be understood that the terms used herein, such as "upper", "above", "lower", "below", etc., indicating spatial relative positions, are used for the purpose of convenience to describe the relationship of one unit or feature relative to another unit or feature as shown in the drawings. The terms of spatial relative positions may 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 invention provides an endoscopic optical system and an endoscope that do not require adjustment of the object distance during the magnification process, thereby improving the operating efficiency and reducing the operating burden of the doctor.

[0058] An endoscope optical system of this embodiment 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 incident surface to the image surface. The arrangement is compact, the optical path layout is optimized, and it adapts to the actual application requirements of the endoscope.

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

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

[0061] The second movable lens group is a movable convex lens group designed with positive refractive power, which is used to compensate for the focus change caused by the movement of the first movable lens group, ensuring that the light is always accurately focused on the image plane.

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

[0063] During the process of adjusting the magnification, the relative positions of the imaging object and the first fixed lens group, the second fixed lens group and the image plane are kept constant, and the first movable lens group and the second movable lens group move synchronously in opposite directions to compensate for the changes in the optical path during the magnification change, so that the imaging focus is stable during the continuous adjustment of the magnification, and the total optical path length of the optical system is kept constant.

[0064] like Figure 3 As shown, when the first movable lens group moves toward the image side to increase the magnification of the system, the second movable lens group moves toward the object side at the same time to compensate for the change in the optical path and maintain the total optical path length of the system constant.

[0065] The total optical path length of the optical system includes the object distance + image distance + lens group spacing in the optical system. 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 the process of continuous adjustment of the magnification of the endoscope optical system, the distance from the endoscope optical system to the object side remains unchanged, the imaging distance remains unchanged, and only the movement of the lens occurs inside the endoscope optical system, thereby maintaining the focal position of the imaging plane unchanged.

[0066] The distance and rate of synchronous reverse movement are precisely designed and optimized to ensure that the total optical path in the light propagation path remains unchanged, thereby achieving parfocality. The parfocality eliminates the need for secondary focusing during the magnification adjustment process, and the imaging focus is always stable on the image plane, greatly improving the efficiency of use and the consistency of the image. It eliminates the operational complexity caused by adjusting the object distance in traditional endoscopes and reduces the burden on doctors.

[0067] The endoscope optical system of this embodiment supports continuous adjustment of magnification, and the adjustment range of magnification can reach 1:6. In wide-angle mode (low magnification), doctors can quickly complete a wide range of lesion screening while maintaining high resolution and low distortion characteristics of imaging. In detail observation mode (higher magnification), the system provides clear local images of lesions through optical magnification to help doctors observe subtle anatomical structures or pathological features. And the continuously adjustable magnification improves diagnostic efficiency, allowing doctors to quickly adapt to different observation needs, avoiding image quality loss caused by electronic magnification, and improving diagnostic accuracy.

[0068] The endoscope optical system of this embodiment is designed with a wavelength in the visible light band of 415nm to 675nm, which provides doctors with clearer and more accurate lesion observation images and reduces the risks of misdiagnosis and missed diagnosis.

[0069] The endoscope optical system of this embodiment is centered on the innovative lens group design and moving mechanism, which not only meets the requirements of high resolution, high magnification and parfocality of medical endoscopes, but also significantly improves the doctor's operational convenience and diagnostic efficiency, and provides a reliable technical guarantee for the promotion and application of optical magnifying endoscopes in the medical field.

[0070] In this embodiment, the first fixed lens group has positive refractive power, the first movable lens group has negative refractive power, the second movable lens group has positive refractive power, and the second fixed lens group has positive refractive power.

[0071] The first fixed lens group initially converges the light from the object through positive refractive power, so that it has higher optical efficiency when entering the first movable lens group. The first movable lens group has negative refractive power, and realizes dynamic adjustment of the light path by diverging light, thereby adjusting the focal length of the system and providing a basis for subsequent magnification changes. The second movable lens group converges the light through positive refractive power, compensates for the change of the light path when the first movable lens group moves, and ensures the stability of the focus. The positive refractive power of the second fixed lens group further converges the light, accurately focusing it on the image plane to complete high-resolution imaging. In this way, the endoscopic optical system of this embodiment can maintain imaging quality within a larger magnification range, while ensuring the stability of the light path, providing doctors with clear, distortion-free images.

[0072] Furthermore, the endoscope optical system also includes a third fixed lens group disposed between the first movable lens group and the second movable lens group, and the third fixed lens group has negative refractive power.

[0073] When the first movable lens group adjusts the focal length, the third fixed lens group can compensate for the optical distortion that may be caused by the change in the optical path, ensuring that the subsequent lens groups can efficiently converge light to the image plane. In addition, the third fixed lens group can also help expand the magnification range, which is particularly effective in high-magnification observation mode, ensuring uniform light distribution when imaging details, further optimizing the optical performance of the system, and improving imaging stability and clarity. In particular, in the process of dynamically adjusting the magnification, it can effectively eliminate imaging errors in high-magnification mode.

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

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

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

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

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

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

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

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

[0082] Next, in combination with Figure 1 、 2 , and the specific numerical parameter table 1 corresponding to the symbols, the specific dimensions of the endoscopic optical system are described.

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

[0084] The first single lens L1, which is a plano-concave lens, with its focal length f1: -1.5 mm < f1 < -1.0 mm. The thickness of the first single lens L1 is CT1, its front surface is a plane, and its rear surface has a radius R2. In addition, the designed object plane of the endoscopic optical system is located before the center of the front surface of the first single lens L1 at a distance D0.

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

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

[0087] The third cemented lens L3 is a biconvex lens with a focal length f3 satisfying 11.2 mm < f3 < 12.2 mm. The thickness of the third cemented lens L3 is CT3, and it follows the second singlet lens L2 with an air gap D3.

[0088] The third cemented lens L3 includes:

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

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

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

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

[0093] As Figure 1 、 2 and shown in Table 1, the first movable lens group includes: The fourth cemented lens L4 has a thickness CT4 and is a biconcave lens with a focal length f4 satisfying -7.0 mm < f4 < -6.5 mm. The fourth cemented lens L4 follows the third cemented lens L3 with an air gap D4. The fourth cemented lens L4 includes:

[0094] The first lens L4.1 has a thickness CT4.1 and is a meniscus lens with a focal length f4.1 satisfying -1.27 < f4.1 / f4 < -1.21, with a front surface radius R11 and a rear surface radius R12. The negative refractive power of the first lens L4.1 performs a preliminary dynamic adjustment on the optical path through divergence. The ratio of its designed focal length range f4.1 to the focal length f4 of the entire lens group is precisely optimized to ensure that no additional aberrations are introduced into the system during the dynamic adjustment of the optical path.

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

[0096] The aperture STOP follows the fourth cemented lens L4 with an air gap D5.

[0097] As Figure 1 、2 As shown in Table 1, the third fixed lens group includes: a fifth single lens L5, which is a biconcave lens with a focal length f5: -7.8 mm < f5 < -7.3 mm. The thickness CT5 of the fifth single lens L5 is followed by an air gap D6 and the stop STOP, with the front surface R15 and the rear surface R16 of the fifth single lens L5. The third fixed lens group is arranged between the first moving lens group and the second moving lens group, and uses its negative refractive power to compensate and balance the dynamic optical path. The biconcave lens structure of the fifth single lens L5 can adjust the ratio of converging light to diverging light, thereby ensuring that the system does not introduce obvious distortion when adjusting the magnification. In the high-magnification mode, it effectively reduces the aberration and field distortion caused by dynamic magnification during the detailed observation process, while maintaining the overall imaging clarity of the system.

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

[0099] A sixth doublet lens L6, which is a biconvex lens with a focal length f6: 5.2 mm < f6 < 5.7 mm. The thickness CT6 of the sixth doublet lens L6 is followed by an air gap D7 and the fifth single lens L5. The sixth doublet lens L6 includes:

[0100] A first lens L6.1 with a thickness CT6.1, which is a biconvex lens with a focal length f6.1: 0.46 < f6.1 / f6 < 0.52, with the front surface radius R17 and the rear surface radius R18; the positive refractive power of the first lens L6.1 makes a preliminary adjustment to the convergence of the optical path, and its focal length range and design ratio match the optical parameters of the entire lens group, so as to achieve stable convergence of light during the dynamic magnification process.

[0101] A second lens L6.2 with a thickness CT6.2, which is a meniscus lens with a focal length f6.2: -1.06 < f6.2 / f6 < -1.01, with the front surface radius R19 and the 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, reducing the problems of aberration and high-order optical distortion.

[0102] The function of the first moving lens group is to disperse light and change the focusing mode of light. During the zooming process, the fourth doublet lens L4 serves as a focusing lens and is responsible for adjusting the focal position of the image by changing the focal length. Since a concave lens scatters light, it is usually used to change the relationship between the object distance and the imaging distance, thereby achieving magnification or reduction. The purpose of focusing is to keep the focus of the system always on the photosensitive surface of the sensor to ensure clear images. 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 through compensation when the focal length of the fourth doublet lens L4 changes, ensuring the stability of the focal position and avoiding image blurring caused by the focusing of the fourth doublet lens L4. The compensation process of the biconvex sixth doublet lens L6 cancels out the focal length change caused by the biconcave fourth doublet lens L4, so that during the entire zooming process, the focal point does not shift, thus achieving the parfocal state.

[0104] The synchronous reverse movement of the first moving lens group and the second moving lens group always keeps the optical path length constant when dynamically adjusting the magnification, ensuring the parfocal characteristic. At the same time, higher imaging resolution and clarity are provided through optical optimization.

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

[0106] The seventh doublet lens L7, which is a meniscus lens, with its focal length f7: -15.4mm < f7 < -14.4mm. The thickness CT7 of the seventh doublet lens L7 follows the sixth doublet lens L6 with an air gap D8. The seventh doublet lens L7 can reduce the divergent deviation of light. The seventh doublet lens L7 includes:

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

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

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

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

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

[0112] The ninth doublet lens L9 is a biconvex lens with a focal length f9 satisfying 6.8 mm < f9 < 7.3 mm. The ninth doublet lens L9 supports high-resolution imaging. The thickness CT9 of the ninth doublet lens L9 is followed by an air gap D10 after the eighth doublet lens L8. The ninth doublet lens L9 includes:

[0113] The first lens L9.1 with a thickness CT9.1 is a biconvex lens with a focal length f9.1 satisfying 0.36 < f9.1 / f9 < 0.40. Its front surface is an aspherical surface with a radius R29, a conic coefficient k, and higher-order coefficients A4, A6, and A8, and the rear surface radius is R30.

[0114] The second lens L9.2 with a thickness CT9.2 is a meniscus lens with a focal length f9.2 satisfying -0.49 < f9.2 / f9 < -0.45. The front surface radius is R31 and the rear surface radius is R32.

[0115] The tenth singlet lens L10 is a biconcave lens. Its thickness CT10 is followed by an air gap D11 after the ninth doublet lens L9. Its focal length f10 satisfies -2.7 mm < f10 < -2.2 mm. Its front surface is R33 and the rear surface is R34.

[0116] The second filter F2 is a afocal singlet lens. The second filter F2 is the protective glass of the image sensor and is followed by an air spacing D12 after the tenth singlet lens L10.

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

[0118] The radius of curvature, thickness, and spacing D of these optical lenses L1 - L10 are shown in Table 1 below.

[0119]

[0120]

[0121]

[0122] Table 1

[0123] Among them, the conic coefficient k and higher-order coefficients A4, A6, and A8 satisfied by the aspherical surface are shown in Table 2. The curve equation of the aspherical surface is expressed as follows:

[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 movable lens group and the second movable lens group is described, wherein the fourth double cemented lens L4 of the first movable lens group is used as the movable group 1, the sixth double cemented lens L6 of the second movable lens group is used as the movable group 2, and the other lenses are relatively stationary. The position change of the movable group 1 and the movable group 2 will cause the change of D4, D5, D7, and D8. During the whole zooming process, D4+D5, D7+D8 remain constant. The numerical relationship diagram of the movement amount is referenced. Figure 4 The specific values ​​are shown in Table 3 below:

[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, this embodiment also provides an endoscope, which includes the above-mentioned endoscope optical system, and an electronic imaging module and a control device connected thereto.

[0131] The electronic imaging module includes 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 CMOS (complementary metal oxide semiconductor) imaging module. The endoscope optical system is responsible for accurately focusing the optical image on the image sensor, which converts the received optical image into an electrical signal and digitizes it through a subsequent processing module. The image sensor is set close to the image plane of the optical system to minimize the signal loss or distortion that may occur during the transmission of the optical signal, ensuring that the clarity and resolution of the final image reach medical grade.

[0132] The endoscope optical system is integrated into a flexible control device, which includes:

[0133] Insertion part: The insertion part is designed as a thin and flexible structure, which can bend freely in a complex cavity to meet the needs of surgery. The front end of the insertion part is equipped with an endoscope optical system and its electronic imaging module to obtain high-resolution images of the lesion.

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

[0135] Operation part: includes control handle, image output interface and operation knob. Doctors can use the control handle to adjust the magnification, field of view direction and image output of the optical system.

[0136] Imaging signal transmission module: The image signal is transmitted from the image sensor to the operating unit, and can be transmitted to an external display device via optical fiber, cable or wirelessly to achieve real-time monitoring.

[0137] The endoscope of this embodiment is flexible and operable in clinical operations, and in particular, the application of soft components can significantly improve the adaptability of the endoscope in complex cavities of the human body.

[0138] The endoscope achieves a perfect balance of miniaturization, high resolution and flexible operation by tightly combining the endoscope optical system, electronic imaging module and control device. The endoscope is flexible and operable in clinical operation, and can significantly improve the endoscope's parfocal shooting, high-resolution imaging and dynamic magnification adjustment in complex cavities of the human body, providing new technical support for modern medical diagnosis and treatment.

[0139] Compared with the commonly used technology, this embodiment has the following beneficial effects:

[0140] The endoscope optical system adopts the synchronous reverse movement design of the first movable lens group and the second movable lens group. When adjusting the magnification, the optical path length remains constant, avoiding focus drift, and realizing seamless switching from wide-angle observation to high-magnification magnification. The entire magnification process does not require adjustment of the object distance, so that the system always maintains a parfocal state, thereby improving operational efficiency and reducing the operating burden of doctors. The magnification is continuously adjustable, allowing doctors to quickly switch to the required magnification, from large-scale screening to fine tissue examination, with smooth and precise operation, providing doctors with clearer lesion image observation conditions. The endoscope optical system has achieved a comprehensive improvement in performance and structure in the field of optical magnification endoscopes.

[0141] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0142] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. An endoscope optical system, characterized in that: Including, arranged in sequence along the optical axis from the incident surface to the image surface: The first fixed lens group, used for initially converging the incident light; The first movable lens group, which is a movable concave lens group, used for adjusting the focal length of the optical system by moving; The second movable lens group, which is a movable convex lens group, used for compensating for the focus change caused by the movement of the second lens group; The second fixed lens group, used for focusing the light onto the image surface; 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 all remain constant. The first movable lens group and the second movable lens group move synchronously in opposite directions to compensate for the optical path change during the zooming process, 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.

2. The endoscope optical system according to claim 1, characterized in that: The first fixed lens group has a positive refractive power, the first movable lens group has a negative refractive power, the second movable lens group has a positive refractive power, and the second fixed lens group has a positive refractive power.

3. The endoscope optical system according to claim 2, characterized in that: The endoscope optical system further includes a third fixed lens group disposed between the first movable lens group and the second movable lens group, and the third fixed lens group has a negative refractive power.

4. The endoscope optical system according to claim 3, characterized in that: The focal lengths of the lenses satisfy the following conditions: The focal length fa of the first fixed lens group: 4 mm < fa < 8 mm; The focal length fb of the first movable lens group: -7.0 mm < fb < -6.5 mm; The focal length fc of the third fixed lens group: -7.8 mm < fc < -7.3 mm; The focal length fd of the second movable lens group: 5.2 mm < fd < 5.7 mm; The focal length fe of the second fixed lens group: 2 mm < fe < 5 mm.

5. The endoscope optical system according to claim 4, characterized in that: The first fixed lens group includes: The first single lens L1, which is a plano-concave lens, and its focal length f1: -1.5 mm < f1 < -1.0 mm; The first filter F1, which is an afocal single lens; The second single lens L2, which is an aspherical lens, and its focal length f2: 3.2 mm < f2 < 4.2 mm; The third doublet lens L3, which is a biconvex lens, and its focal length f3: 11.2 mm < f3 < 12.2 mm. The third doublet lens L3 includes: The first lens L3.1, which is a meniscus lens, and its focal length f3.1: -0.79 < f3.1 / f3 < -0.74; The second lens L3.2, which is a biconvex lens, and its focal length f3.2: 0.42 < f3.2 / f3 < 0.

48.

6. The endoscope optical system according to claim 4, characterized in that: The first movable lens group includes: The fourth doublet lens L4, which is a biconcave lens, and its focal length f4: -7.0 mm < f4 < -6.5 mm. The fourth doublet lens L4 includes: The first lens L4.1, which is a meniscus lens, and its focal length f4.1: -1.27 < f4.1 / f4 < -1.21; The second lens L4.2, which is a biconcave lens, and its focal length f4.2: 3.81 < f4.2 / f4 < 3.

87.

7. The endoscope optical system according to claim 4, characterized in that: The third fixed lens group includes: The fifth single lens L5, which is a biconcave lens, and its focal length f5: -7.8 mm < f5 < -7.3 mm.

8. The endoscope optical system according to claim 4, characterized in that: The second movable lens group includes: The sixth doublet lens L6 is a biconvex lens, and its focal length f6 satisfies: 5.2mm < f6 < 5.7mm. The sixth doublet lens L6 includes: The first lens L6.1 is a biconvex lens, and its focal length f6.1 satisfies: 0.46 < f6.1 / f6 < 0.52; The second lens L6.2 is a meniscus lens, and its focal length f6.2 satisfies: -1.06 < f6.2 / f6 < -1.

01.

9. The endoscope optical system according to claim 4, characterized in that: The second fixed lens group includes: The seventh doublet lens L7 is a meniscus lens, and its focal length f7 satisfies: -15.4mm < f7 < -14.4mm. The seventh doublet lens L7 includes: The first lens L7.1 is a biconvex lens, and its focal length f7.1 satisfies: -0.26 < f7.1 / f7 < -0.20; The second lens L7.2 is a biconcave lens, and its focal length f7.2 satisfies: 0.18 < f7.2 / f7 < 0.22; The eighth doublet lens L8 is a biconvex lens, and its focal length f8 satisfies: 3.9mm < f8 < 4.5mm. The eighth doublet lens L8 includes: The first lens L8.1 is a biconvex lens, and its focal length f8.1 satisfies: 0.51 < f8.1 / f8 < 0.56; The second lens L8.2 is a meniscus lens, and its focal length f8.2 satisfies: -1.38 < f8.2 / f8 < -1.33; The ninth doublet lens L9 is a biconvex lens, and its focal length f9 satisfies: 6.8mm < f9 < 7.3mm. The ninth doublet lens L9 includes: The first lens L9.1 is a biconvex lens, and its focal length f9.1 satisfies: 0.36 < f9.1 / f9 < 0.40; The second lens L9.2 is a meniscus lens, and its focal length f9.2 satisfies: -0.49 < f9.2 / f9 < -0.45; The tenth singlet lens L10 is a biconcave lens, and its focal length f10 satisfies: -2.7mm < f10 < -2.2mm; The second filter F2 is a afocal singlet lens.

10. An endoscope, characterized in that: The endoscope includes the endoscope optical system according to any one of claims 1 to 9, and an electronic imaging module and a control device connected thereto.

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