High-magnification liquid telecentric optical system and lens

Abstract

The invention relates to the technical field of visual inspection, in particular to a high-magnification liquid telecentric optical system and a lens. The optical system comprises a first lens, a first balsaming lens, a second lens, a second balsaming lens, a liquid lens, a seventh lens, an eighth lens and a third balsaming lens which are sequentially arranged in the main optical axis direction of the optical system from the object side to the image side. The first lens is a concave-convex lens, the first balsaming lens is a convex lens, the second lens is a concave-convex lens, and the second balsaming lens is a convex lens. The seventh lens is a plane mirror, the eighth lens is a concave-convex lens, and the third bonding lens is a concave-convex lens. According to the invention, while five-time high-magnification optical detection is realized, low telecentricity is stably maintained in a focusing range of 30mm-60mm, the contradiction between high magnification and small depth of field is effectively improved, low optical distortion can be realized in a detection depth range, and detection precision, application range, cost control and imaging quality are considered.

Description

Technical Field

[0001] This invention relates to the field of visual inspection technology, and in particular to a high-magnification liquid telecentric optical system and lens. Background Technology

[0002] With the continuous development of mechanical intelligence, telecentric lenses are used in fields such as high-precision dimensional measurement, micro-component identification, and high-precision defect detection. Telecentric lenses have attracted attention due to their excellent optical performance, such as no parallax, small distortion, high resolution, and greater depth of field compared to other lenses.

[0003] Visual inspection typically requires high imaging accuracy and a large detection depth in scenarios with small fields of view. High optical magnification can bring high imaging accuracy. However, in geometric optics, the optical magnification of a lens is inversely proportional to its depth of field; that is, the higher the optical magnification, the smaller the depth of field. This situation creates a contradictory limitation between detection accuracy and detection depth in many visual inspection applications.

[0004] The conventional solution on the market is to use a bulky vision platform to address changes in detection depth caused by environmental vibrations, and then use manual rollers or precision motors to compensate for the working distance of each refocusing during movement. This results in very low efficiency for each manual refocusing during inspection, making it almost impossible to meet the requirements of automated vision inspection. On the other hand, motorized compensation often requires precise laser ranging for guidance, which is too expensive and difficult to apply to many equipment and inspection scenarios where inspection costs are limited. Summary of the Invention

[0005] To address the challenges of balancing imaging accuracy and detection depth, low focusing efficiency, and high system costs in high-magnification visual inspection, this invention aims to provide a high-magnification liquid telecentric optical system and lens that resolves the conflict between accuracy and depth of field at high optical magnification, while avoiding the problems of low focusing efficiency or high testing costs caused by manual focusing or electric compensation.

[0006] To achieve the objectives of this invention, firstly, this invention provides a high-magnification liquid telecentric optical system, employing the following technical solution: A high-magnification liquid telecentric optical system includes: a first lens, a first cemented lens, a second lens, a second cemented lens, a liquid lens, a seventh lens, an eighth lens, and a third cemented lens arranged sequentially along the principal optical axis of the optical system from the object plane side to the image plane side. The focusing position of the optical system is adjusted by controlling the driving voltage or driving current of the liquid lens. The object plane of the first lens is a concave spherical surface, and the image plane is a convex spherical surface. The object plane and image plane of the first cemented lens are both convex spherical surfaces. The object plane and image plane of the second lens are both concave spherical surfaces, and the image plane of the second cemented lens are both convex spherical surfaces. The object plane and image plane of the seventh lens are plane mirrors. The object plane and image plane of the eighth lens are both concave spherical surfaces, and the image plane of the third cemented lens are both concave spherical surfaces.

[0007] The implementation can include any or all of the following features.

[0008] In one embodiment, the first cemented lens includes a third lens and a fourth lens, the third lens being fixed to the object side of the fourth lens, the object surface of the third lens being a convex spherical surface and the image surface being a concave spherical surface, and the object surface and image surface of the fourth lens being convex spherical surfaces; the second cemented lens includes a fifth lens and a sixth lens, the fifth lens being fixed to the object side of the sixth lens, the object surface and image surface of the fifth lens being convex spherical surfaces, and the object surface of the sixth lens being a concave spherical surface and the image surface being a convex spherical surface; the third cemented lens includes a ninth lens and a tenth lens, the ninth lens being fixed to the object side of the tenth lens, the object surface of the ninth lens being a concave spherical surface and the image surface being a convex spherical surface, and the object surface of the tenth lens being a concave spherical surface and the image surface being a convex spherical surface.

[0009] In one embodiment, the first lens has an object plane radius of curvature of -53.72 mm and an image plane radius of curvature of -28.98 mm; the third lens has an object plane radius of curvature of 72.97 mm and an image plane radius of curvature of 25.62 mm; the fourth lens has an object plane radius of curvature of 25.62 mm and an image plane radius of curvature of -25.62 mm; the second lens has an object plane radius of curvature of -21.24 mm and an image plane radius of curvature of -114.27 mm; and the fifth lens has an object plane radius of curvature of... The sixth lens has an object plane radius of curvature of -35.61 mm and an image plane radius of curvature of -47.29 mm; the eighth lens has an object plane radius of curvature of -9.87 mm and an image plane radius of curvature of -57.24 mm; the ninth lens has an object plane radius of curvature of -9.62 mm and an image plane radius of curvature of -6.45 mm; and the tenth lens has an object plane radius of curvature of -6.45 mm and an image plane radius of curvature of -12.21 mm.

[0010] In one embodiment, the optical interval between the first lens and the first cemented lens is 0.08 mm to 0.12 mm, the optical interval between the first cemented lens and the second lens is 0.08 mm to 0.12 mm, the optical interval between the second lens and the second cemented lens is 0.13 mm to 0.17 mm, the optical interval between the second cemented lens and the liquid lens is 69.98 mm to 70.02 mm, the optical interval between the liquid lens and the seventh lens is 11.98 mm to 12.02 mm, the optical interval between the seventh lens and the eighth lens is 13.98 mm to 14.02 mm, and the optical interval between the eighth lens and the third cemented lens is 4.98 mm to 5.02 mm.

[0011] In one embodiment, the initial focusing object distance is 43 mm, and the distance from the center of curvature of the image plane of the tenth lens to the image plane of the optical system is 15 mm.

[0012] In one embodiment, the focal length of the first lens is 75.484 mm; the focal length of the third lens is -43.187 mm; the focal length of the fourth lens is 26.956 mm; the focal length of the second lens is -38.472 mm; the focal length of the fifth lens is 33.262 mm; the focal length of the sixth lens is -145.394 mm; the focal length of the seventh lens is infinity; the focal length of the eighth lens is -16.896 mm; the focal length of the ninth lens is 14.916 mm; and the focal length of the tenth lens is -16.048 mm.

[0013] In one embodiment, the optical system has a focal length of 9mm and an aperture of F17.

[0014] In one embodiment, the optical system is object-side telecentric with a telecentricity of 0.011% and an optical magnification of 5x.

[0015] In one embodiment, the liquid lens is provided with an aperture stop, the focusing distance of the liquid lens is in the range of 30mm to 60mm, and the liquid lens is a Corning A58 liquid lens.

[0016] Secondly, the lens provided by this invention adopts the following technical solution: A lens comprising the optical system described in any of the preceding claims.

[0017] In summary, the present invention provides a high-magnification liquid telecentric optical system and lens, which has the following beneficial effects: First, this invention integrates a liquid lens into the telecentric optical path and precisely designs the number, shape, radius of curvature, focal length parameters, and optical spacing between the lenses on both sides of the liquid lens. This expands the optical magnification to 5x, achieving high-precision detection while maintaining a stable low level of telecentricity. Furthermore, it achieves focusing within a range of 30mm to 60mm through the liquid lens, expanding the effective detection depth and resolving the contradiction between high magnification and shallow depth of field. Moreover, it can achieve fast autofocus without relying on a bulky vision platform and drive motor, resulting in lower costs.

[0018] Secondly, the optical system of the present invention sets the system focal length to 9mm and the aperture to F17, and with the specific optical parameters of each lens, achieves low optical distortion within the detection depth range, further optimizing the balance between imaging clarity and depth of field, and ensuring that the image is clearly distinguishable within the detection depth range at high magnification. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the optical path structure of the optical system in the embodiment; Figure 2 The optical sector diagram of the embodiment's optical system; Figure 3 Distortion and field curvature diagrams of the optical system in the example; Figure 4 The modulation optical transfer function curve of the optical system in the example is shown. Figure 5 The image plane illuminance curve of the optical system in the example is shown. Figure 6 This is a schematic diagram of the circle of confusion of the optical system in the example.

[0020] Explanation of reference numerals in the attached figures: 1. First lens group; 11. First lens; 12. First cemented lens; 121. Third lens; 122. Fourth lens; 13. Second lens; 14. Second cemented lens; 141. Fifth lens; 142. Sixth lens; 2. Liquid lens; 3. Second lens group; 31. Seventh lens; 32. Eighth lens; 33. Third cemented lens; 331. Ninth lens; 332. Tenth lens. Detailed Implementation

[0021] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, back, bottom, and top, are only for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present invention.

[0022] To address the challenges of balancing imaging accuracy and detection depth, low focusing efficiency, or high system costs in high-magnification visual inspection, this invention first discloses a high-magnification liquid telecentric optical system. This system resolves the conflict between detection accuracy and depth of field at high optical magnification and avoids the problems of low focusing efficiency or high testing costs caused by manual focusing or electric compensation.

[0023] Figure 1 This is a schematic diagram of the high-magnification liquid telecentric optical system of the present invention, hereinafter referred to as the optical system. (Refer to...) Figure 1 The optical system consists of a liquid lens 2, an aperture stop, and multiple glass lenses. All lenses and aperture stops are arranged in sequence according to a certain optical interval and rotate around the principal optical axis of the optical system.

[0024] Reference Figure 1The optical system has an object side on the left, with an object plane A, and an image side on the right, with an image plane B. Object plane A is the ideal object plane of the optical system, and image plane B is the ideal image plane of the optical system. The photosensitive target surface of the CMOS chip coincides with the image plane B of the optical system. The lens of the optical system includes a first lens group 1, a liquid lens 2, and a second lens group 3 arranged sequentially along the principal optical axis from the object plane A side to the image plane B side. The liquid lens 2 is positioned close to the second lens group 3. The first lens group 1, from the object plane A side to the image plane B side, includes a first lens 11, a first cemented lens 12, a second lens 13, and a second cemented lens 14. The first cemented lens 12 includes a third lens 121 and a fourth lens 122. The third lens 121 is fixed to the object plane A side of the fourth lens 122. The second cemented lens 14 includes a fifth lens 141 and a sixth lens 142. The fifth lens 141 is fixed to the object plane A side of the sixth lens 142. The second lens group 3, from the object plane A side to the image plane B side, includes a seventh lens 31, an eighth lens 32, and a third cemented lens 33. The third cemented lens 33 includes a ninth lens 331 and a tenth lens 332. The ninth lens 331 is fixed to the object plane A side of the tenth lens 332. The cemented lenses can be fixed by optical adhesives or by mechanical means, such as positioning grooves for clamping and fixing.

[0025] Reference Figure 1 For ease of description, the optical surface of each lens facing the object plane A of the optical system is defined as the object plane of that lens, and the optical surface of each lens facing the image plane B of the optical system is defined as the image plane of that lens. The curvature of the optical surface of each lens facing the object plane A is defined as the object plane curvature, and the curvature of the optical surface of each lens facing the image plane B is defined as the image plane curvature, with the curvature being positive when the convex side faces the object plane A and negative when the convex side faces the image plane B. In the first lens group 1, the object plane of the first lens 11 is a concave spherical surface, and the image plane is a convex spherical surface. The object plane of the third lens 121 is a convex spherical surface, and the image plane is a concave spherical surface. The object plane and image plane of the fourth lens 122 are both convex spherical surfaces. The object plane of the second lens 13 is a concave spherical surface, and the image plane is a convex spherical surface. The object plane and image plane of the fifth lens 141 are both convex spherical surfaces, and the object plane of the sixth lens 142 is a concave spherical surface, and the image plane is a convex spherical surface. The first lens group 1 is used to receive the light emitted by the object, initiate the convergence process, and complete most of the aberration correction to form a high-quality intermediate image.

[0026] Referring to the figure, in the second lens group 3, the object plane and image plane of the seventh lens 31 are plane mirrors; the object plane of the eighth lens 32 is a concave spherical surface and the image plane is a convex spherical surface; the object plane of the ninth lens 331 is a concave spherical surface and the image plane is a convex spherical surface; and the object plane of the tenth lens 332 is a concave spherical surface and the image plane is a convex spherical surface. The second lens group 3 transmits the light beam at the liquid lens 2 and adjusts it into parallel light output, completing telecentric imaging and image plane matching.

[0027] Reference Figure 1 The light-transmitting aperture within the liquid lens 2 serves as an aperture stop and is integrated within the liquid lens 2. The liquid lens 2 includes a driving circuit that applies a driving voltage or current to the electrodes of the liquid lens 2, changing its diopter and enabling rapid focusing at different working distances. By combining the liquid lens 2 within the optical path of the glass lens, object-side telecentricity is achieved, and by changing its diopter in milliseconds, the focal position of the optical system is rapidly adjusted. This allows for clear imaging of objects at different object distances within the working range of the liquid lens onto a fixed sensor, effectively extending the detection depth.

[0028] Reference Figure 1 The curvature data of each lens are as follows: The object plane curvature radius of the first lens 11 is -53.72 mm, and the image plane curvature radius is -28.98 mm. The object plane curvature radius of the third lens 121 is 72.97 mm, and the image plane curvature radius is 25.62 mm. The object plane curvature radius of the fourth lens 122 is 25.62 mm, and the image plane curvature radius is -25.62 mm. The object plane curvature radius of the second lens 13 is -21.24 mm, and the image plane curvature radius is -114.27 mm. The object plane curvature radius of the fifth lens 141 is 55.17 mm, and the image plane curvature radius is -35.61 mm. The object plane curvature radius of the sixth lens 142 is -35.61 mm, and the image plane curvature radius is -47.29 mm. The eighth lens 32 has an object plane radius of curvature of -9.87 mm and an image plane radius of curvature of -57.24 mm. The ninth lens 331 has an object plane radius of curvature of -9.62 mm and an image plane radius of curvature of -6.45 mm; the tenth lens 332 has an object plane radius of curvature of -6.45 mm and an image plane radius of curvature of -12.21 mm. The surface profile tolerances for all curvatures are f / 3-5, with local f / 3-0.5 tolerances, which can be measured using an interferometer.

[0029] Referring to the reference figure, the distance from the center of curvature of the object surface of the first lens 11 to the image plane B of the optical system is the total optical length of the optical system, which is 164.971 mm. The initial focusing object distance refers to the distance from the center of curvature of the object surface of the first lens 11 to the object plane A of the optical system, which is 43 mm. The image distance refers to the distance from the center of curvature of the image surface of the tenth lens 332 to the image plane B of the optical system, which is 15 mm. Specifically, the optical interval between the first lens 11 and the first cemented lens 12 is 0.08mm~0.12mm, the optical interval between the first cemented lens 12 and the second lens 13 is 0.08mm~0.12mm, the optical interval between the second lens 13 and the second cemented lens 14 is 0.13mm~0.17mm, the optical interval between the second cemented lens 14 and the liquid lens 2 is 69.98mm~70.02mm, the optical interval between the liquid lens 2 and the seventh lens 31 is 11.98mm~12.02mm, the optical interval between the seventh lens 31 and the eighth lens 32 is 13.98mm~14.02mm, and the optical interval between the eighth lens 32 and the third cemented lens 33 is 4.98mm~5.02mm.

[0030] Reference Figure 1 The optical system has a focal length of 9mm. The first lens 11 has a focal length of 75.484mm, possessing the strongest positive optical power. Its main function is to initiate the light convergence process and undertake most of the refractive task of the optical system. Its meniscus design helps control aberrations from the outset. The third lens 121 has a focal length of -43.187mm, and the fourth lens 122 has a focal length of 26.956mm. The first cemented lens 12, composed of the third lens 121 and the fourth lens 122, serves as the first cemented group to eliminate chromatic aberration, correcting axial chromatic aberration and spherical aberration to ensure that light of different colors converges to a single point. The second lens 13 has a focal length of -38.472mm, and its negative optical power is used to balance the total optical power of the optical system. The fifth lens 141 has a focal length of 33.262mm, and the sixth lens 142 has a focal length of -145.394mm. The second cemented lens 14, composed of the fifth lens 141 and the sixth lens 142, serves as the second cemented group to eliminate chromatic aberration, further correcting residual chromatic aberration. Ultimately, the optical characteristics of each lens in the first lens group 1 work together to ensure that the optical system can still achieve extremely low distortion and high optical modulation transfer function (MTF) at a high magnification of 5x.

[0031] Reference Figure 1The focusing distance range of the liquid lens 2 is 30mm to 60mm, and the focal length of the seventh lens 31 is infinite. The focal length of the eighth lens 32 is -16.896mm, and its negative power and surface design are used to collimate and preprocess the diverging beam emitted from the aperture stop (liquid lens). The focal length of the ninth lens 331 is 14.916mm, and the focal length of the tenth lens 332 is -16.048mm. The third cemented lens 33, composed of the ninth lens 331 and the tenth lens 332, is used to control the final phase aberration balance and match its focal length to the image plane, achieving high illumination uniformity and high edge sharpness.

[0032] Reference Figure 1 The optical system consists of 7 groups of 10 glass lenses and a liquid lens 2. All glass lenses are made of Chengdu Guangming colorless glass. Specifically, the first lens 11 is made of crown glass H-K9L, the third lens 121 is made of heavy lanthanum flint glass H-ZLaF75A, and the fourth lens 122 is made of fluorine crown glass H-FK61. The second lens 13 is made of lanthanum crown glass H-LaK8B, the fifth lens 141 is made of heavy phosphorus crown glass H-ZPK5, and the sixth lens 142 is made of lanthanum flint glass H-LaF4. The seventh lens 31 is made of crown glass H-K9L, and the eighth lens 32 is made of heavy crown glass H-ZK3. The ninth lens 331 is made of heavy flint glass H-ZF10, and the tenth lens 332 is made of heavy crown glass H-ZK14. The liquid lens 2 is a Corning A58 series liquid lens, preferably a Corning A58N0 liquid lens.

[0033] Reference Figure 1 The optical system is object-side telecentric with a telecentricity of 0.011%, an optical magnification of 5x, an aperture of F17, an object-side numerical aperture of 0.145, a maximum optical distortion of 0.0594%, an optimal focusing distance of 43mm, and operates in a visible light environment within the wavelength range of 486nm-650nm. It is suitable for industrial cameras with an image plane diameter of 11.2mm or less.

[0034] The high-magnification liquid telecentric optical system of this embodiment can be applied to telecentric lenses. When using this telecentric lens to detect non-planar (curved surfaces, stepped surfaces, etc.) feature objects, the image within the detection depth range is clearly distinguishable, and fast focusing can be achieved, thereby improving detection efficiency.

[0035] The following will combine Figure 2-6 The imaging quality of the high-magnification liquid telecentric optical system in this embodiment will be further explained.

[0036] Figure 2The optical sector diagram of the optical system in this embodiment shows the set of aberrations generated in different field-of-view regions. In the optical sector diagram of each object plane, the left image represents the meridional plane, and the right image represents the sagittal plane. The difference between the meridional and sagittal plane aberrations can be seen in each field-of-view region. It can be seen that the aberration curves in the meridional and sagittal directions under each object plane are within a very small offset range, and the curve shape is highly consistent under different object distances. This indicates that the optical system effectively corrects the aberrations in both the meridional and sagittal planes throughout the entire detection depth, and can simultaneously ensure the imaging accuracy in the object height and perpendicular to the object height directions, achieving image quality stability after the combination of the telecentric optical path and the liquid lens.

[0037] Figure 3 This is a distortion and field curvature diagram of the optical system in this embodiment. The left side shows the field curvature (image plane curvature). Different curves represent different wavelengths. It can be seen that the maximum field of view is 1.120 mm, the sagittal field curvature is 0.1785 mm, and the meridional field curvature is 0.2411 mm. The maximum deviation of the image plane curvature is no more than 0.2411 mm, which can be ignored. The right side shows the optical distortion. The maximum field of view is 1.120 mm. Generally, the position of the largest distortion occurs at the edge of the entire field of view, and the maximum optical distortion is less than 0.0594%, which meets the design requirements.

[0038] Figure 4 This is the modulation optical transfer function (MTF) curve of the optical system in this embodiment, representing the spatial transfer function of the entire optical system within the operating wavelength band, reflecting the imaging quality of the entire imaging system. The horizontal axis represents line pairs / mm, and the vertical axis represents frequency. Different lines represent different fields of view and differences in meridion or sagitta. It can be seen that at low to medium spatial frequencies, the MTF value remains above 0.4, and at high spatial frequencies, the MTF value still remains above the resolvable threshold. Furthermore, the MTF curves corresponding to different object distances and different fields of view highly overlap, with minimal deviation. This indicates that the contrast transfer capability of this optical system is relatively stable and efficient, with excellent imaging consistency, ensuring that the detailed information of the detected target is clearly transmitted within a detection depth range of 30mm~60mm at 5x magnification.

[0039] Figure 5 This is an image plane illuminance curve of the optical system in this embodiment, mainly showing the illumination distribution in different areas of the image plane after light passes through the optical system, and reflecting the attenuation of illuminance in different fields of view. This figure is an important indicator for evaluating the image plane illuminance of the entire optical system. It can be seen from the figure that the image illuminance at the edge can reach more than 95% of the illuminance at the center.

[0040] Figure 6This is a schematic diagram of the circle of confusion of the optical system in this embodiment, representing the diffusion of all entrance pupil rays converging on the image plane in different field-of-view areas. Different curves represent different wavelengths, which is also an important way to evaluate the overall imaging characteristics of an optical system. As can be seen from this figure, within the designed wavelength range, the geometric radii of the center field-of-view confusion spot and the edge field-of-view confusion spot can both reach within 12.22 micrometers of the Airy disk radius.

[0041] The optical system in this embodiment integrates liquid lenses into the telecentric optical path. Through precise design of lens configuration, optical parameters, and spacing, it achieves multi-lens synergy, extending the optical magnification to 5x. This meets the demands of high-precision inspection while maintaining stable low telecentricity within a focusing range of 30mm to 60mm, thus expanding the detection depth and effectively mitigating the conflict between high magnification and shallow depth of field. Furthermore, it achieves low optical distortion within the detection depth range, balancing inspection accuracy, applicability, cost control, and image quality, providing a more efficient, flexible, and economical solution for high-precision optical inspection.

[0042] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention.

Claims

1. A high-magnification liquid telecentric optical system, characterized in that, include: The optical system consists of a first lens, a first cemented lens, a second lens, a second cemented lens, a liquid lens, a seventh lens, an eighth lens, and a third cemented lens arranged sequentially from the object plane side to the image plane side along the principal optical axis. The focusing position of the optical system is adjusted by controlling the driving voltage or driving current of the liquid lens. The first lens has a concave spherical object plane and a convex spherical image plane; the first cemented lens has a convex spherical object plane and a convex spherical image plane; the second lens has a concave spherical object plane and a convex spherical image plane; the seventh lens has a plane mirror object plane and an image plane; the eighth lens has a concave spherical object plane and a convex spherical image plane; and the third cemented lens has a concave spherical object plane and a convex spherical image plane.

2. The high-magnification liquid telecentric optical system as described in claim 1, characterized in that, The first cemented lens includes a third lens and a fourth lens. The third lens is fixed to the object side of the fourth lens. The object surface of the third lens is a convex spherical surface, and the image surface is a concave spherical surface. The object surface and image surface of the fourth lens are both convex spherical surfaces. The second cemented lens includes a fifth lens and a sixth lens. The fifth lens is fixed to the object side of the sixth lens. The object surface and image surface of the fifth lens are both convex spherical surfaces. The object surface of the sixth lens is a concave spherical surface, and the image surface is a convex spherical surface. The third cemented lens includes a ninth lens and a tenth lens. The ninth lens is fixed to the object side of the tenth lens. The object surface of the ninth lens is a concave spherical surface, and the image surface is a convex spherical surface. The object surface of the tenth lens is a concave spherical surface, and the image surface is a convex spherical surface.

3. The high-magnification liquid telecentric optical system as described in claim 2, characterized in that, The first lens has an object plane radius of curvature of -53.72 mm and an image plane radius of curvature of -28.98 mm; the third lens has an object plane radius of curvature of 72.97 mm and an image plane radius of curvature of 25.62 mm; the fourth lens has an object plane radius of curvature of 25.62 mm and an image plane radius of curvature of -25.62 mm; the second lens has an object plane radius of curvature of -21.24 mm and an image plane radius of curvature of -114.27 mm; and the fifth lens has an object plane radius of curvature of 55.1 mm. The object plane radius of curvature of the sixth lens is -35.61mm, and the image plane radius of curvature is -47.29mm; the object plane radius of curvature of the eighth lens is -9.87mm, and the image plane radius of curvature is -57.24mm; the object plane radius of curvature of the ninth lens is -9.62mm, and the image plane radius of curvature is -6.45mm; the object plane radius of curvature of the tenth lens is -6.45mm, and the image plane radius of curvature is -12.21mm.

4. The high-magnification liquid telecentric optical system as described in claim 3, characterized in that, The optical spacing between the first lens and the first cemented lens is 0.08mm~0.12mm, the optical spacing between the first cemented lens and the second lens is 0.08mm~0.12mm, the optical spacing between the second lens and the second cemented lens is 0.13mm~0.17mm, the optical spacing between the second cemented lens and the liquid lens is 69.98mm~70.02mm, the optical spacing between the liquid lens and the seventh lens is 11.98mm~12.02mm, the optical spacing between the seventh lens and the eighth lens is 13.98mm~14.02mm, and the optical spacing between the eighth lens and the third cemented lens is 4.98mm~5.02mm.

5. A high-magnification liquid telecentric optical system as described in claim 3, characterized in that, The initial focusing object distance is 43mm, and the distance from the center of curvature of the image plane of the tenth lens to the image plane of the optical system is 15mm.

6. The high-magnification liquid telecentric optical system as described in claim 2, characterized in that, The first lens has a focal length of 75.484 mm; the third lens has a focal length of -43.187 mm; the fourth lens has a focal length of 26.956 mm; the second lens has a focal length of -38.472 mm; the fifth lens has a focal length of 33.262 mm; the sixth lens has a focal length of -145.394 mm; the seventh lens has an infinite focal length; the eighth lens has a focal length of -16.896 mm; the ninth lens has a focal length of 14.916 mm; and the tenth lens has a focal length of -16.048 mm.

7. A high-magnification liquid telecentric optical system as described in claim 6, characterized in that, The optical system has a focal length of 9mm and an aperture of F17.

8. The high-magnification liquid telecentric optical system as described in claim 1, characterized in that, The optical system is object-centric with a telecentricity of 0.011% and an optical magnification of 5x.

9. A high-magnification liquid telecentric optical system as described in claim 1, characterized in that, The liquid lens has an aperture stop inside, and the focusing distance of the liquid lens is in the range of 30mm to 60mm. The liquid lens is a Corning A58 liquid lens.

10. A lens, characterized in that, Includes the optical system described in any one of claims 1 to 9.

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