Optical lens

Abstract

An optical lens disclosed by the present invention comprises a first lens group, a liquid lens and a second lens group which are sequentially arranged from an object space to an image space along an optical axis, the first lens group has positive focal power, the second lens group has positive focal power, the first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, and the fifth lens comprises a fourth lens and a fifth lens. The second lens group comprises a sixth lens, a seventh lens, an eighth lens and a ninth lens, the first lens has negative focal power, the second lens has negative focal power, the third lens has positive focal power, the fourth lens has positive focal power, the fifth lens has negative focal power, the sixth lens has positive focal power, the seventh lens has negative focal power, and the ninth lens has negative focal power. The eighth lens has positive focal power, and the ninth lens has negative focal power. According to the optical lens provided by the embodiment of the invention, the original fixed working distance focusing optical lens is expanded into the working distance adjustable optical lens within the range of 1935mm, and the optical lens is small in size, light in weight and low in cost.

Description

Technical Field

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

[0002] With the development of science and technology in the field of intelligent automation, the application of machine vision in automated inspection and code scanning has become more and more extensive, especially in the fields of high-precision dimensional measurement, rapid detection of tiny defects and accurate identification of tiny devices, where optical lenses are used.

[0003] Among them, the tilt-shift optical lens has received widespread attention in application scenarios such as code scanning due to its excellent optical properties such as small distortion, high resolution, and small size, and its ability to provide a relatively large depth of field and special viewing angle adjustment capabilities.

[0004] However, with the continuous improvement of the requirements for detection speed, although ordinary tilt-shift optical lenses provide a larger depth of field compared to other traditional lenses, they still cannot meet some application scenarios that require an ultra-large depth of field. In addition, the current tilt-shift optical lenses have a relatively large number of lenses and a relatively complex structure, which makes the optical lenses heavy, requires a large space and is costly. Summary of the invention

[0005] The present invention provides an optical lens to solve the problems of insufficient depth of field, large size, high cost, etc.

[0006] The present invention provides an optical lens, comprising a first lens group, a liquid lens and a second lens group, which are sequentially arranged from the object side to the image side along the optical axis;

[0007] The first lens group has positive optical power, and the second lens group has positive optical power;

[0008] The first lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object side to the image side;

[0009] The second lens group includes a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the object side to the image side;

[0010] The first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power.

[0011] Optionally, the object side surface of the first lens is convex, and the image side surface is concave;

[0012] The object side surface of the second lens is concave, and the image side surface is concave;

[0013] The object side surface of the third lens is convex, and the image side surface is convex;

[0014] The object side surface of the fourth lens is convex, and the image side surface is convex;

[0015] The object side surface of the fifth lens is convex, and the image side surface is concave;

[0016] The object side surface of the sixth lens is concave, and the image side surface is convex;

[0017] The object side surface of the seventh lens is concave, and the image side surface is convex;

[0018] The object side surface of the eighth lens is convex, and the image side surface is convex;

[0019] The object side surface of the ninth lens is concave, and the image side surface is convex.

[0020] Optionally, the optical lens further includes a diaphragm;

[0021] The aperture is located in the optical path between the fifth lens and the liquid lens;

[0022] or,

[0023] The aperture is located in the optical path between the liquid lens and the sixth lens.

[0024] Optionally, the optical lens further includes a flat glass, and the flat glass is located on the image side of the ninth lens;

[0025] The distance between the first lens and the second lens on the optical axis is d1; the distance between the second lens and the third lens on the optical axis is d2; the distance between the third lens and the fourth lens on the optical axis is d3; the distance between the fourth lens and the fifth lens on the optical axis is d4;

[0026] 1.11mm≤d1≤1.31mm; 0.52mm≤d2≤0.72mm;

[0027] 0.11mm≤d3≤0.31mm; 0.04mm≤d4≤0.24mm;

[0028] The aperture is located between the fifth lens and the liquid lens, the distance between the fifth lens and the aperture on the optical axis is d5, the distance between the aperture and the liquid lens on the optical axis is d6, the distance between the liquid lens and the sixth lens on the optical axis is d7, the distance between the seventh lens and the eighth lens on the optical axis is d8, and the distance between the ninth lens and the flat glass on the optical axis is d9;

[0029] 0.55mm≤d5≤0.75mm; 0.05mm≤d6≤0.25mm;

[0030] 0.55mm≤d7≤0.75mm; 0.12mm≤d8≤0.32mm;

[0031] 6.02mm≤d9≤6.82mm.

[0032] Optionally, the refractive power of the liquid lens is D, -9≤D≤6.

[0033] Optionally, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5,

[0034] -1≤f4 / f5<0.

[0035] Optionally, the distance between the object side surface of the fourth lens and the image side surface of the fourth lens on the optical axis is d10, the distance between the image side surface of the fifth lens and the object side surface of the liquid lens on the optical axis is d11, and 0<d10 / d11≤5.

[0036] Optionally, the chief ray angle of the optical lens is greater than or equal to 10° and less than or equal to 15°.

[0037] Optionally, the focal length of the second lens is f2, and the focal length of the optical lens is f, -3≤f2 / f<0.

[0038] Optionally, a central curvature radius of the object side surface of the second lens is R1, a central curvature radius of the image side surface of the second lens is R2, and 0≤(R1+R2) / (R1-R2)≤1.22.

[0039] Optionally, the sixth lens and the seventh lens form a first cemented lens group;

[0040] and / or,

[0041] The eighth lens and the ninth lens form a second cemented lens group.

[0042] Optionally, the focal length of the third lens is f3, the focal length of the fourth lens is f4, and 0<f3 / f4≤1.

[0043] Optionally, the thickness of the first lens on the optical axis is d12, the total optical length of the optical lens is TTL, and 0<d12 / TTL≤0.08.

[0044] Optionally, a distance between the third lens and the fourth lens on the optical axis is d3, a distance between the object side surface of the fourth lens and the image side surface of the fourth lens on the optical axis is d10, and 0≤d3 / d10≤5.

[0045] Optionally, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, and -20≤f5 / f6<1.

[0046] The optical lens provided by the embodiment of the present invention is provided with a first lens group, a liquid lens and a second lens group that cooperate with each other, and realizes variable compensation for different working distances by the variable optical focal length of the liquid lens, and eliminates the aberration introduced by the liquid lens when the curvature changes at a large depth of field by setting the number of lenses (10 optical lenses) in the first lens group and the second lens group located on both sides of the liquid lens and the optical focal length distribution of each lens, thereby expanding the original optical lens with a fixed working distance focus to an optical lens with an adjustable working distance within a range of 1935mm, so that the optical lens has a wider range of applications, and the number of lenses is small, and the total optical length can be reduced to about 20mm. It is small in size, light in weight and low in cost, which helps to reduce the overall hardware cost of the visual detection solution, thereby significantly improving work efficiency.

[0047] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 A schematic diagram of the structure of an optical lens provided by an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of the optical path of another optical lens provided by an embodiment of the present invention;

[0051] Figure 3 A field curvature diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm;

[0052] Figure 4 A field curvature diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000mm;

[0053] Figure 5 A distortion diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm;

[0054] Figure 6 A distortion diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000 mm;

[0055] Figure 7 An optical transfer function diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm;

[0056] Figure 8 An optical transfer function diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000 mm;

[0057] Fig. 9 An axial chromatic aberration diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm;

[0058] Fig.10 An axial chromatic aberration diagram of an optical lens provided in an embodiment of the present invention when the working distance is 2000 mm. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0061] Figure 1 A schematic diagram of the structure of an optical lens provided by an embodiment of the present invention, Figure 2 A schematic diagram of the optical path of another optical lens provided by an embodiment of the present invention is shown in FIG. Figure 1 and Figure 2 As shown, the optical lens provided by the embodiment of the present invention includes a first lens group 100, a liquid lens LQ and a second lens group 200 arranged in sequence from the object side to the image side along the optical axis. The first lens group 100 has positive optical power, and the second lens group 200 has positive optical power. The first lens group 100 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5 arranged in sequence from the object side to the image side. The second lens group 200 includes a sixth lens 6, a seventh lens 7, an eighth lens 8 and a ninth lens 9 arranged in sequence from the object side to the image side. The first lens 1 has a negative optical power, the second lens 2 has a negative optical power, the third lens 3 has a positive optical power, the fourth lens 4 has a positive optical power, the fifth lens 5 has a negative optical power, the sixth lens 6 has a positive optical power, the seventh lens 7 has a negative optical power, the eighth lens 8 has a positive optical power, and the ninth lens 9 has a negative optical power.

[0062] The optical axis refers to the principal optical axis of the optical lens. The object side is also called the object side, and the image side is also called the image side.

[0063] The focal power is used to characterize the refraction of an incident parallel light beam by an optical system. When the focal power is positive, the refraction is convergent, and when the focal power is negative, the refraction is divergent. Moreover, the larger the absolute value of the focal power, the stronger the light bending ability, and the smaller the absolute value of the focal power, the weaker the light bending ability.

[0064] In this embodiment, if Figure 1 and Figure 2 As shown, the first lens group 100, the liquid lens LQ and the second lens group 200 are arranged in sequence along the propagation direction of the incident light, and the centers of the lenses in the first lens group 100, the liquid lens LQ and the second lens group 200 are collinear.

[0065] The first lens group 100 has a positive optical power, and is used to correspond to the main optical path of the object field of view and converge the light emitted from various angles of the object light emitting point.

[0066] Further, the first lens group 100 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5, and the first lens 1, the second lens 2, the third lens 3, the fourth lens 4 and the fifth lens 5 are arranged in sequence from the object side to the image side along the optical axis.

[0067] The first lens 1 has negative optical power and is mainly used to collect light emitted from the object.

[0068] The second lens 2 has negative optical power and is used to deflect the light passing through the first lens 1 and to perform a certain optical power adjustment.

[0069] The third lens 3 has positive refractive power and is used to reduce the incident angle of light so that the light can enter the subsequent lens more smoothly.

[0070] The fourth lens 4 has positive refractive power and is used to balance aberrations and ensure the quality of light after passing through the first few lenses.

[0071] The fifth lens 5 has negative optical power, and mainly introduces light to the object side surface of the liquid lens LQ (eg, the location of the aperture), so as to prepare for subsequent light adjustment.

[0072] Continue to refer Figure 1 and Figure 2 The optical power of the second lens group 200 is positive, and it is used to correspond to the optical path of the image field, converging the optical paths at various angles of the image side to ensure the image size and the magnification of the optical lens.

[0073] The second lens group 200 includes a sixth lens 6, a seventh lens 7, an eighth lens 8 and a ninth lens 9, and the sixth lens 6, the seventh lens 7, the eighth lens 8 and the ninth lens 9 are arranged in sequence from the object side to the image side along the optical axis.

[0074] Furthermore, the sixth lens 6 has positive focal power, the seventh lens 7 has negative focal power, the eighth lens 8 has positive focal power, and the ninth lens 9 has negative focal power. Through the combination of different lenses and their specific focal power design, the remaining aberrations can be corrected more finely to ensure that the light can be accurately converged onto the image plane, and the size of the final image and the optical magnification of the lens can be accurately controlled to ensure good imaging effects.

[0075] It should be noted that the ninth lens element 9 has a negative optical power, which can be used to reduce the field curvature of the optical lens, thereby reducing aberrations and improving image quality.

[0076] Furthermore, if Figure 1 and Figure 2 As shown, a liquid lens LQ is arranged between the first lens group 100 and the second lens group 200. The liquid lens LQ is an optical element without mechanical connection made of one or more liquids, and has a fast and stable deformation characteristic under the control of a driving signal.

[0077] The liquid lens LQ can change the focal length by changing the curvature of the liquid in the liquid lens LQ through the control of an external driving signal (such as a driving voltage or a driving current).

[0078] Therefore, the focus position of the optical lens can be adjusted in real time by adjusting the driving signal (such as driving voltage or driving current) applied to the liquid lens LQ, that is, the focal length of the optical lens can be adjusted. The curvature of the liquid lens LQ is different for different driving signals, so that it can correspond to different working distances and achieve the purpose of fast focusing at different working distances.

[0079] In this embodiment, the dynamic compensation of the working distance (i.e., the object distance) is achieved by changing the front and rear curvatures of the liquid lens LQ, thereby playing a zooming role on the entire optical lens, which can enable the optical lens to maintain a good focusing effect within a wider working distance range, so as to achieve the purpose of clear imaging of the optical lens at different object distances. For example, the optical lens provided in the embodiment of the present invention can quickly focus within the object distance range of 65mm-2000mm to obtain a clear image, and achieve a depth of field of 1935mm, which helps to improve the detection efficiency and greatly reduce the cost of the detection equipment.

[0080] Among them, since the liquid lens LQ is used to achieve focusing, during the focusing process, each lens does not move, the stability is better, and the focusing speed is faster.

[0081] At the same time, the first lens group 100, the liquid lens LQ and the second lens group 200 cooperate with each other to achieve variable compensation for different working distances through the variable optical focal length of the liquid lens LQ, and by setting the number of lenses in the first lens group 100 and the second lens group 200 located on both sides of the liquid lens LQ and the optical focal length distribution of each lens, the aberration introduced by the liquid lens LQ when the curvature changes at a large depth of field is eliminated, thereby expanding the original optical lens with a fixed working distance focus to an optical lens with an adjustable working distance within the range of 1935mm, so that the optical lens has a wider range of applications, which helps to reduce the overall hardware cost of the visual inspection solution and significantly improve work efficiency.

[0082] Among them, the optical lens provided by the embodiment of the present invention can be used to work in a wide wavelength range of 430nm to 650nm, which includes the main part of the visible spectrum and is suitable for a variety of high-precision imaging and detection applications.

[0083] Optionally, the liquid lens LQ can adopt an electrowetting effect lens, which regulates the wetting characteristics of the liquid on the solid surface through an electric field, thereby changing the shape of the droplet and the curvature of the lens to achieve dynamic adjustment of the focal length, so that the liquid lens LQ does not require any mechanical movement, has a fast response speed, low energy consumption, and a simple structure.

[0084] In other embodiments, the liquid lens LQ may also be other types of liquid lenses, such as a gradient refractive index lens, etc., which is not specifically limited in the embodiment of the present invention.

[0085] In summary, the optical lens provided in the embodiment of the present invention is provided with a first lens group, a liquid lens and a second lens group that cooperate with each other, and realizes variable compensation for different working distances through the variable optical focal length of the liquid lens, and eliminates the aberration introduced by the liquid lens when the curvature changes at a large depth of field by setting the number of lenses (10 optical lenses) in the first lens group and the second lens group located on both sides of the liquid lens and the optical focal length distribution of each lens, thereby expanding the original optical lens with a fixed working distance focus to an optical lens with an adjustable working distance within a range of 1935mm, so that the optical lens has a wider range of applications, and the number of lenses is small, and the total optical length can be reduced to about 20mm. It is small in size, light in weight and low in cost, which helps to reduce the overall hardware cost of the visual detection solution, thereby significantly improving work efficiency.

[0086] As a feasible implementation method, Figure 1 and Figure 2 As shown, the object side surface of the first lens 1 is convex, and the image side surface is concave; the object side surface of the second lens 2 is concave, and the image side surface is concave; the object side surface of the third lens 3 is convex, and the image side surface is convex; the object side surface of the fourth lens 4 is convex, and the image side surface is convex; the object side surface of the fifth lens 5 is convex, and the image side surface is concave; the object side surface of the sixth lens 6 is concave, and the image side surface is convex; the object side surface of the seventh lens 7 is concave, and the image side surface is convex; the object side surface of the eighth lens 8 is convex, and the image side surface is convex; the object side surface of the ninth lens 9 is concave, and the image side surface is convex.

[0087] The object side of the lens refers to the side of the lens facing the object, and the image side refers to the side of the lens facing the image.

[0088] In this embodiment, if Figure 1 and Figure 2 As shown, the first lens 1 is a convex-concave lens, that is, the object side of the first lens 1 is convex toward the object side, and the image side of the first lens 1 is concave toward the image side. The second lens 2 is a biconcave lens, the object side of the second lens 2 is concave toward the object side, and the image side of the second lens 2 is concave toward the image side. The third lens L3 is a biconvex lens, the object side of the third lens 3 is convex toward the object side, and the image side of the third lens 3 is convex toward the image side. The fourth lens 4 is a biconvex lens. The object side of the fourth lens 4 is convex toward the object side, and the image side of the fourth lens 4 is convex toward the image side. The fifth lens 5 is a convex-concave lens. The object side of the fifth lens 5 is convex toward the object side, and the image side of the fifth lens 5 is concave toward the image side. This helps to converge the divergent light toward the optical axis, and through the combination of different lenses and their specific curved surface design (such as convex-concave combination), the aberration is corrected to a certain extent, providing a partially converged light beam with preliminary aberration correction for the subsequent liquid lens LQ and the second lens group 200, laying the foundation for the final formation of a clear and high-quality image.

[0089] Continue to refer Figure 1 and Figure 2 , the sixth lens 6 is a concave-convex lens, the object side of the sixth lens 6 is concave toward the object side, and the image side of the sixth lens 6 is convex toward the image side. The seventh lens 7 is a concave-convex lens, the object side of the seventh lens 7 is concave toward the object side, and the image side of the seventh lens 7 is convex toward the image side. The eighth lens 8 is a biconvex lens, the object side of the eighth lens 8 is convex toward the object side, and the image side of the eighth lens 8 is convex toward the image side. The ninth lens 9 is a concave-convex lens, the object side of the ninth lens 9 is concave toward the object side, and the image side of the ninth lens 9 is convex toward the image side. Among them, through the combination of different lenses and their specific curved surface design (such as a concave-convex combination), the remaining aberrations can be corrected more finely to ensure that the light can be accurately converged on the image plane, and the size of the final image and the optical magnification of the lens can be accurately controlled to ensure that the final image has high resolution and good visual effects.

[0090] It should be noted that the ninth lens 9 adopts a concave-convex lens, which is beneficial to reducing the field curvature of the optical lens, thereby reducing aberrations and improving image quality.

[0091] As a feasible implementation method, Figure 1 and Figure 2 As shown, the optical lens further includes a stop STO, which is located in the optical path between the fifth lens 5 and the liquid lens LQ.

[0092] Alternatively, the stop STO is located in the optical path between the liquid lens LQ and the sixth lens 6 .

[0093] Among them, the aperture STO is used to limit the light beam or the size of the imaging range (field of view). The aperture STO is set between the fifth lens 5 and the liquid lens LQ, or between the liquid lens LQ and the sixth lens 6. That is, the aperture STO is placed in front of or behind the liquid lens LQ, which can control the incident light beam and brightness and improve the imaging quality.

[0094] As a feasible implementation, the aperture STO can be located on the edge, frame or specially provided perforated screen of the liquid lens LQ. In other words, the optical lens may not be provided with an independent aperture, but the edge, frame, etc. of the liquid lens LQ may be used as an aperture to limit the size of the light beam passing through the lens, which helps to simplify the lens structure and reduce the number of components.

[0095] As a feasible implementation method, Figure 1 and Figure 2 As shown, the optical lens further includes a flat glass PL, and the flat glass PL is located on the image side of the ninth lens 9.

[0096] The distance between the first lens 1 and the second lens 2 on the optical axis is d1; the distance between the second lens 2 and the third lens 3 on the optical axis is d2; the distance between the third lens 3 and the fourth lens 4 on the optical axis is d3; and the distance between the fourth lens 4 and the fifth lens 5 on the optical axis is d4.

[0097] 1.11mm≤d1≤1.31mm; 0.52mm≤d2≤0.72mm;

[0098] 0.11mm≤d3≤0.31mm; 0.04mm≤d4≤0.24mm;

[0099] The aperture STO is located between the fifth lens 5 and the liquid lens LQ, the distance between the fifth lens 5 and the aperture STO on the optical axis is d5, the distance between the aperture STO and the liquid lens LQ on the optical axis is d6, the distance between the liquid lens LQ and the sixth lens 6 on the optical axis is d7, the distance between the seventh lens 7 and the eighth lens 8 on the optical axis is d8, and the distance between the ninth lens 9 and the flat glass PL on the optical axis is d9.

[0100] 0.55mm≤d5≤0.75mm; 0.05mm≤d6≤0.25mm;

[0101] 0.55mm≤d7≤0.75mm; 0.12mm≤d8≤0.32mm;

[0102] 6.02mm≤d9≤6.82mm.

[0103] The distance between adjacent lenses on the optical axis is also the optical spacing distance between the two lenses.

[0104] Specifically, the optical spacing between the first lens 1 and the second lens 2 is between 1.21 mm ± 0.1 mm, that is, the optical spacing between the first lens 1 and the second lens 2 is greater than or equal to 1.11 mm and less than or equal to 1.31 mm. The optical spacing between the second lens 2 and the third lens 3 is between 0.62 mm ± 0.1 mm, that is, the optical spacing between the second lens 2 and the third lens 3 is greater than or equal to 0.52 mm and less than or equal to 0.72 mm, and so on. The optical spacing between the third lens 3 and the fourth lens 4 is between 0.21 mm ± 0.1 mm, and the optical spacing between the fourth lens 4 and the fifth lens 5 is between 0.14 mm ± 0.1 mm.

[0105] Continue to refer Figure 1 and Figure 2, taking the aperture STO being located between the fifth lens 5 and the liquid lens LQ as an example, the optical spacing between the fifth lens 5 and the aperture STO is between 0.65 mm±0.1 mm; the optical spacing between the aperture STO and the liquid lens LQ is between 0.15 mm±0.1 mm.

[0106] In addition, the optical distance between the liquid lens LQ and the sixth lens 6 is between 0.65 mm±0.1 mm; the optical distance between the seventh lens 7 and the eighth lens 8 is between 0.22 mm±0.1 mm.

[0107] Furthermore, the optical interval between the ninth lens 9 and the flat glass PL is between 6.42 mm±0.4 mm.

[0108] In this embodiment, by properly setting the spacing between adjacent lenses on the optical axis, it is helpful to further correct imaging aberrations and achieve high-definition imaging in a wide range of object distances. At the same time, the overall structure of the optical imaging lens can be made more compact, and the miniaturized design of the optical imaging lens can be achieved, which is beneficial for later assembly.

[0109] It should be noted that the optical spacing distances between the above-mentioned lenses can be flexibly adjusted as needed and are not limited to the distances listed above.

[0110] As a feasible implementation manner, the refractive power of the liquid lens LQ is D, -9≤D≤6.

[0111] Specifically, according to different driving voltages or driving currents, the liquid lens LQ may have different refractive powers to correspond to different working distances.

[0112] In this embodiment, by changing the diopter range of the liquid lens LQ, the working distance range of the optical lens can be adjusted, thereby expanding the depth of field range of the optical lens.

[0113] Furthermore, by setting the refractive power D of the liquid lens LQ to satisfy -9≤D≤6, a large depth of field of 1935 mm can be achieved while maintaining the imaging quality. For example, when the refractive power of the liquid lens LQ is -9, the corresponding working distance of the optical lens can reach 2000 mm; when the refractive power of the liquid lens LQ is 6, the corresponding working distance of the optical lens can reach 65 mm.

[0114] In this way, in barcode scanning applications, the dynamic adjustment capability of the liquid lens LQ can enable the optical lens to quickly adapt to barcodes at different distances, ensuring the accuracy and efficiency of scanning.

[0115] In industrial automation, this optical lens can be used to detect workpieces at different distances, such as large mechanical parts, small electronic components, etc., providing high-resolution and low-color-difference images to improve detection accuracy.

[0116] As a feasible implementation manner, the focal length of the fourth lens 4 is f4, the focal length of the fifth lens 5 is f5, and -1≤f4 / f5<0.

[0117] Among them, the convergence ability of the fourth lens 4 enables the light to be more concentratedly converged to the aperture position after the fifth lens 5, providing a better basis for the dynamic adjustment of the liquid lens LQ.

[0118] The divergence effect of the fifth lens 5 can offset part of the aberration introduced by the fourth lens 4, ensuring that the light has been preliminarily corrected before entering the liquid lens LQ.

[0119] In this embodiment, by reasonably setting the focal length ratio of the fourth lens 4 and the fifth lens 5, the same magnification can be achieved under different object distance ranges, so that the optical lens can maintain stable imaging quality under different working distances, which is beneficial to reducing the parallax of the final imaging, especially in large depth of field applications, and can ensure that different objects from near to far can be clearly imaged.

[0120] As a feasible implementation, the distance between the object side surface of the fourth lens 4 and the image side surface of the fourth lens 4 on the optical axis is d10, and the distance between the image side surface of the fifth lens 5 and the object side surface of the liquid lens LQ on the optical axis is d11, 0<d10 / d11≤5.

[0121] Among them, the fourth lens 4 is used as a converging lens, which can further converge the light after passing through the third lens 3. The distance d10 between the object side surface of the fourth lens 4 and the image side surface of the fourth lens 4 on the optical axis (that is, the thickness of the fourth lens 4) can affect the propagation path of the light inside the lens, and thus affect the imaging quality.

[0122] The fifth lens 5 is a diverging lens, which can be used to adjust the path of the light so that it reaches an appropriate diverging state before entering the liquid lens LQ. The distance d11 between the fifth lens 5 and the liquid lens LQ can affect the convergence point position of the light and the aberration correction effect.

[0123] In this embodiment, by reasonably setting the distance d10 between the object side surface of the fourth lens 4 and the image side surface of the fourth lens 4 on the optical axis and the distance d11 between the image side surface of the fifth lens 5 and the object side surface of the liquid lens LQ on the optical axis to satisfy 0<d10 / d11≤5, it is ensured that the light can be more concentratedly converged to the aperture position (i.e., the object side position of the liquid lens LQ) after the fifth lens 5. This design helps to improve the clarity and resolution of the imaging, and can achieve the same magnification under different object distance ranges, so that the optical lens can maintain stable imaging quality under different working distances, which is conducive to reducing the parallax of the final imaging, especially in large depth of field applications, it can ensure that different objects from near to far can be clearly imaged.

[0124] As a feasible implementation, the chief ray angle of the optical lens is greater than or equal to 10° and less than or equal to 15°.

[0125] The chief ray angle CRA refers to the angle between the light emitted from the object point and the optical axis on the image plane after passing through the lens system.

[0126] In this embodiment, by setting the chief ray angle CRA of the optical lens to satisfy 10°≤CRA≤15°, it is possible to ensure uniform distribution of light on the image plane without significantly increasing the number of lenses, and to achieve the same magnification under different object distance ranges, which is beneficial to reducing the parallax of the final imaging, thereby helping to expand the depth of field and ensure that light can form a clear image on objects at different distances, especially in large depth of field applications, such as barcode scanning, industrial detection, etc., which can effectively reduce aberrations and improve imaging clarity and resolution.

[0127] As a feasible implementation manner, the focal length of the second lens 2 is f2, the focal length of the optical lens is f, -3≤f2 / f<0.

[0128] The second lens 2 is a diverging lens, which can be used to deflect the light after passing through the first lens 1 and undertake a certain optical focal adjustment task.

[0129] In this embodiment, by reasonably setting the ratio between the focal length f2 of the second lens 2 and the focal length f of the optical lens, the aberration can be effectively balanced and the imaging quality of the optical lens can be improved. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the focal length design of the second lens 2 can further optimize the propagation path of the light, so that the lens can maintain stable imaging quality at different working distances. Especially in large depth of field applications, it can ensure that different objects from near to far can be clearly imaged.

[0130] As a feasible implementation manner, the central curvature radius of the object side surface of the second lens 2 is R1, the central curvature radius of the image side surface of the second lens 2 is R2, and 0≤(R1+R2) / (R1-R2)≤1.22.

[0131] Among them, by reasonably setting the relationship between the central curvature radius R1 of the object side of the second lens 2 and the central curvature radius R2 of the image side of the second lens 2, the aberration can be effectively reduced without significantly affecting the overall optical focal length, thereby improving the imaging quality of the optical lens. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the focal length design of the second lens 2 can further optimize the propagation path of the light, so that the lens can maintain stable imaging quality at different working distances. Especially in large depth of field applications, it can ensure that different objects from near to far can be clearly imaged.

[0132] As a feasible implementation method, Figure 1 and Figure 2 As shown, the sixth lens 6 and the seventh lens 7 form a first cemented lens group 11.

[0133] The sixth lens 6 and the seventh lens 7 are provided to form the first cemented lens group 11, which is beneficial to reducing the spherical aberration between the light of the near optical axis and the light of the far optical axis, and reducing the influence of dispersion on imaging.

[0134] At the same time, the air gap between the sixth lens 6 and the seventh lens 7 can be effectively reduced, thereby further reducing the total length of the lens. Under the premise of compact structure, the resolution can be improved, the optical properties such as distortion can be optimized, and the light loss caused by reflection between lenses can be reduced, the illumination can be increased, thereby improving the image quality and the clarity of the lens imaging.

[0135] In addition, the use of the first cemented lens group 11 can also reduce the number of assembly components between the two lenses, simplify the assembly procedures in the lens manufacturing process, reduce costs, and effectively reduce errors that occur when configuring the lens, reduce the tolerance sensitivity of the lens unit due to tilt / eccentricity and other tolerances generated during the assembly process, and improve imaging resolution and imaging quality.

[0136] As a feasible implementation method, Figure 1 and Figure 2 As shown, the eighth lens 8 and the ninth lens 9 form a second cemented lens group 12.

[0137] The eighth lens 8 and the ninth lens 9 are provided to form the second cemented lens group 12, which is beneficial to reducing the spherical aberration between the light of the near optical axis and the light of the far optical axis, and reducing the influence of dispersion on imaging.

[0138] At the same time, the air gap between the eighth lens 8 and the ninth lens 9 can be effectively reduced, thereby further reducing the total length of the lens. Under the premise of compact structure, the resolution can be improved, the optical properties such as distortion can be optimized, and the light loss caused by reflection between lenses can be reduced, the illumination can be increased, thereby improving the image quality and the clarity of the lens imaging.

[0139] In addition, the use of the second cemented lens group 12 can also reduce the number of assembly components between the two lenses, simplify the assembly procedures during the lens manufacturing process, reduce costs, and effectively reduce errors that occur when configuring the lens, reduce the tolerance sensitivity of the lens unit due to tilt / eccentricity and other tolerances generated during the assembly process, and improve imaging resolution and imaging quality.

[0140] As a feasible implementation manner, the focal length of the third lens 3 is f3, the focal length of the fourth lens 4 is f4, and 0<f3 / f4≤1.

[0141] The third lens 3 is used as a converging lens, which can further converge the light after passing through the second lens 2, reduce the diffusion angle of the light, and ensure that the light can enter the subsequent lens more concentratedly.

[0142] The fourth lens 4 also serves as a converging lens, and its larger focal length can be used to balance aberrations, ensuring that the light can be more concentratedly converged to the aperture position (i.e., the object side position of the liquid lens LQ) after the fifth lens 5.

[0143] In this embodiment, by reasonably setting the focal length f3 of the third lens 3 and the focal length f4 of the fourth lens 4 to satisfy 0<f3 / f4≤1, the aberration can be effectively reduced without significantly affecting the overall optical focal length, thereby improving the imaging quality of the optical lens. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the same magnification can be achieved under different object distance ranges, which is conducive to reducing the parallax of the final imaging, thereby extending the depth of field and ensuring that the light can be clearly imaged on objects at different distances, especially in large depth of field applications, such as barcode scanning, industrial detection, etc., which can effectively reduce aberrations and improve the clarity and resolution of imaging.

[0144] As a feasible implementation manner, the thickness of the first lens 1 on the optical axis is d12, the total optical length of the optical lens is TTL, and 0<d12 / TTL≤0.08.

[0145] The thickness d12 of the first lens 1 on the optical axis can be understood as the distance between the object-side surface of the first lens 1 and the image-side surface of the first lens 1 on the optical axis.

[0146] The total optical length TTL of the optical lens refers to the distance from the center of the optical axis of the object side of the first lens 1 to the image plane.

[0147] As the first lens of the optical system, the first lens 1 can be used to initially introduce light and adjust the incident angle of the light. The thickness d12 of the first lens 1 on the optical axis has a direct impact on the propagation path of the light. An appropriate thickness helps to reduce aberrations and improve imaging quality.

[0148] In this embodiment, by limiting the ratio between the thickness d12 of the first lens 1 on the optical axis and the total optical length TTL, the volume and weight of the lens can be greatly reduced without significantly affecting the optical performance, making it more compact.

[0149] As a feasible implementation manner, the distance between the third lens 3 and the fourth lens 4 on the optical axis is d3, the distance between the object side surface of the fourth lens 4 and the image side surface of the fourth lens 4 on the optical axis is d10, and 0≤d3 / d10≤5.

[0150] The distance d3 between the third lens 3 and the fourth lens 4 on the optical axis can be understood as the on-axis distance from the image side surface of the third lens 3 to the object side surface of the fourth lens 4 .

[0151] The distance d10 between the object-side surface of the fourth lens 4 and the image-side surface of the fourth lens 4 on the optical axis can be understood as the thickness of the fourth lens 4 on the optical axis.

[0152] In this embodiment, by reasonably limiting the distance d3 between the third lens 3 and the fourth lens 4 on the optical axis and the distance d10 between the object side surface of the fourth lens 4 and the image side surface of the fourth lens 4 on the optical axis to satisfy 0≤d3 / d10≤5, the propagation path of the light can be optimized and the aberration can be reduced without significantly affecting the overall optical power. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the same magnification can be achieved under different object distance ranges, which is conducive to reducing the parallax of the final imaging, thereby extending the depth of field and ensuring that the light can form a clear image on objects at different distances.

[0153] As a feasible implementation manner, the focal length of the fifth lens 5 is f5, the focal length of the sixth lens 6 is f6, and -20≤f5 / f6<1.

[0154] Among them, by reasonably limiting the focal length f5 of the fifth lens 5 and the focal length f6 of the sixth lens 6 to satisfy -20≤f5 / f6<1, the absolute value of the focal length of the fifth lens 5 is greater than the absolute value of the focal length of the sixth lens 6. At this time, the fifth lens 5 has a larger divergence angle for light than the sixth lens 6, so that the fifth lens 5 can optimize the light path in a wider angle range and reduce aberrations. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the same magnification can be achieved under different object distance ranges, which is conducive to reducing the parallax of the final imaging, thereby extending the depth of field and ensuring that the light can be clearly imaged on objects at different distances.

[0155] As a feasible implementation manner, the radius of curvature of the object side surface of the first lens 1 is 15.2mm±0.1mm, and the radius of curvature of the image side surface is 6.3mm±0.1mm. The radius of curvature of the object side surface of the second lens 2 is -22.2mm±0.2mm, and the radius of curvature of the image side surface is 15.4mm±0.1mm. The radius of curvature of the object side surface of the third lens 3 is 987.2mm±0.1mm, and the radius of curvature of the image side surface is -21.2mm±0.2mm. The radius of curvature of the object side surface of the fourth lens 4 is 15.6mm±0.2mm, and the radius of curvature of the image side surface is 19.2mm±0.2mm. The radius of curvature of the object side surface of the fifth lens 5 is 8.3mm±0.1mm, and the radius of curvature of the image side surface is 5.2mm±0.1mm. The object side surface of the sixth lens 6 has a radius of curvature of -21.1 mm ± 0.1 mm, and the image side surface has a radius of curvature of -5.4 mm ± 0.2 mm. The object side surface of the seventh lens 7 has a radius of curvature of -5.4 mm ± 0.2 mm, and the image side surface has a radius of curvature of -8.6 mm ± 0.2 mm. The object side surface of the eighth lens 8 has a radius of curvature of 18.2 mm ± 0.1 mm, and the image side surface has a radius of curvature of -7.3 mm ± 0.1 mm. The object side surface of the ninth lens 9 has a radius of curvature of -7.3 mm ± 0.1 mm, and the image side surface has a radius of curvature of -22.4 mm ± 0.2 mm.

[0156] The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface is bent toward the object plane, with the center of the circle close to the image plane; a negative value means that the surface is bent toward the image plane, with the center of the circle close to the object plane.

[0157] In this embodiment, by reasonably setting the curvature radius of the object side and the image side of each lens, the imaging aberration can be further corrected and the imaging quality can be improved. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the same magnification can be achieved under different object distance ranges, which is beneficial to reduce the parallax of the final imaging, thereby extending the depth of field and ensuring that light can form a clear image on objects at different distances.

[0158] As a feasible implementation manner, the refractive index of the first lens 1 is 1.56±0.05, and the Abbe number is 64.8±0.02. The refractive index of the second lens 2 is 1.78±0.05, and the Abbe number is 34.2±0.02. The refractive index of the third lens 3 is 1.65±0.05, and the Abbe number is 55.3±0.02. The refractive index of the fourth lens 4 is 1.76±0.05, and the Abbe number is 45.8±0.02. The refractive index of the fifth lens 5 is 1.90±0.05, and the Abbe number is 30.6±0.02. The refractive index of the sixth lens 6 is 1.65±0.05, and the Abbe number is 58.6±0.02. The refractive index of the seventh lens 7 is 1.78±0.05, and the Abbe number is 30.6±0.02. The refractive index of the eighth lens 8 is 1.56±0.05, and the Abbe number is 56.6±0.02. The refractive index of the ninth lens 9 is 1.82±0.05, and the Abbe number is 23.6±0.02.

[0159] Among them, the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices.

[0160] The Abbe number is an index used to indicate the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0161] In this embodiment, by reasonably limiting the refractive index and Abbe number of each lens, the aberration can be corrected to a greater extent and the imaging quality can be improved. At the same time, combined with the dynamic adjustment capability of the liquid lens LQ, the same magnification can be achieved under different object distance ranges, which is beneficial to reduce the parallax of the final imaging, thereby extending the depth of field and ensuring that light can form a clear image on objects at different distances.

[0162] It should be noted that the curvature radius, refractive index and Abbe number of the first lens 1 to the ninth lens 9 are examples in which each lens is a glass spherical mirror, but are not limited thereto.

[0163] In other embodiments, the first lens 1 to the ninth lens 9 may also be a plastic aspherical lens, a glass spherical lens or a combination of the two, which is not specifically limited in the embodiment of the present invention.

[0164] In addition, in order to ensure the imaging quality, the aperture deviation of each lens is not large, and the radius of curvature of each lens can be constrained within the 3 aperture range of Newton's rings. While achieving a wide object distance range and improving the imaging quality, the thickness of each lens can also be made uniform, making it easy to process and assemble.

[0165] It is understandable that the shape parameters of each lens can be flexibly adjusted as needed and are not limited to the parameters listed above. The curvature and materials of all the above lenses can also be optimized through various aberration corrections to ensure the optical performance and stability of the optical lens.

[0166] As a feasible implementation, the liquid lens LQ includes a driving circuit assembly, which is used to apply a driving voltage or a driving current to the electrodes of the liquid lens LQ to adjust the curvature of the object side and the image side of the liquid lens, thereby changing the focal length, thereby achieving the focusing purpose at different working distances.

[0167] Specific embodiments of the optical lens applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0168] Table 1 describes in detail the radius of curvature, thickness, refractive index and Abbe number of each lens in the optical lens provided in the embodiment in a feasible implementation manner. The optical lens in Table 1 may correspond to Figure 1 and Figure 2 The lens shown.

[0169] Table 1 Parameters of each lens in the optical lens

[0170] Surface number Radius of curvature thickness Refractive Index Abbe number 1 15.2 1.22 1.56 64.8 2 6.3 1.21 3 -22.2 1.12 1.78 34.2 4 15.4 0.62 5 987.2 1.98 1.65 55.3 6 -21.2 0.21 7 15.6 1.56 1.76 45.8 8 19.2 0.14 9 8.3 2.98 1.90 30.6 10 5.2 0.80 LQ \ 0.65 11 -21.1 1.23 1.65 58.6 12 -5.4 0.88 1.78 30.6 13 -8.6 0.22 14 18.2 2.34 1.56 56.6 15 -7.3 1.24 1.82 23.6 16 -22.4 6.42

[0171] Wherein, a lens usually includes two surfaces, each of which is a refractive surface, and the surface numbers in Table 1 are numbered according to the surfaces of each lens. Wherein, surface number 1 is the object side surface of the first lens 1, and surface number 2 is the image side surface of the first lens 1. Surface number 3 is the object side surface of the second lens 2, and surface number 4 is the image side surface of the second lens 2. Surface number 5 is the object side surface of the third lens 3, and surface number 6 is the image side surface of the third lens 3. Surface number 7 is the object side surface of the fourth lens 4, and surface number 8 is the image side surface of the fourth lens 4. Surface number 9 is the object side surface of the fifth lens 5, and surface number 10 is the image side surface of the fifth lens 5. Surface number 11 is the object side surface of the sixth lens 6, surface number 12 is the image side surface of the sixth lens 6 or the object side surface of the seventh lens 7, surface number 13 is the image side surface of the seventh lens 7, and surface number 14 is the object side surface of the eighth lens 8. The image-side surface of the eighth lens 8 with surface number 15 is the object-side surface of the ninth lens 9 , and the surface with surface number 16 is the image-side surface of the ninth lens 9 .

[0172] The radius of curvature represents the degree of curvature of the lens surface. A positive radius of curvature value indicates that the center of curvature is on the side of the surface close to the image, and a negative radius of curvature value indicates that the center of curvature is on the side of the surface far from the image. The "\" in the radius of curvature column indicates that the surface is a plane. The unit of the radius of curvature is mm. The value in the thickness column indicates the axial distance from the current surface to the next surface, and the unit of thickness is mm. The refractive index column indicates the refractive index of the medium between the current surface and the next surface. The blank space in the refractive index column is the refractive index of air, and the refractive index of air is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light, and the blank space indicates that the current position is air.

[0173] Among them, the working wavelength of the optical lens is between 430nm-650nm, the working distance is between 65mm-2000mm, the maximum half field of view is 882.2mm±5mm, and the focal length is 8mm±0.5mm.

[0174] The optical lens can achieve the purpose of focusing without moving the lens by applying a driving signal to the liquid lens to make its surface deform rapidly.

[0175] Therefore, the optical lens of the above embodiment can focus quickly within the object distance range of 65mm-2000mm, which not only improves the efficiency of detection, but also greatly reduces the cost of detection equipment and labor costs.

[0176] Further, Figure 3 A field curvature diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm, Figure 4 A field curvature diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000 mm, such as Figure 3 and Figure 4 As shown, the solid line represents the Tangential curve, and the dotted line represents the Sagittal curve. The unit of the horizontal axis is millimeter, and the vertical axis corresponds to the (half) field of view interval +Y of the optical lens.

[0177] Figure 5 A distortion diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm, Figure 6 The distortion diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000mm is as follows: Figure 5 and Figure 6 As shown, the horizontal axis is the percentage of distortion, and the vertical axis corresponds to the (half) field of view range of the optical lens.

[0178] The analysis images shown in this embodiment only study the half-field performance. From the field curvature diagram and distortion diagram of the optical lens at different working distances, it can be seen that the field curvature of the optical lens provided in this embodiment is effectively controlled at the working distances of 65mm and 2000mm. At the same time, the maximum distortion generally appears at the entire edge of the field of view, and the distortion is distributed according to the law of gradually increasing from small to large fields of view. The maximum distortion of the optical lens is 1%. Therefore, the distortion of the optical lens at the working distances of 65mm and 2000mm is also well corrected, so that the optical lens can maintain a high imaging quality at a wide range of working distances.

[0179] Figure 7 The optical transfer function diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm, Figure 8 The optical transfer function diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000mm is as follows: Figure 7 and Figure 8 As shown, the horizontal axis is the spatial frequency, the vertical axis is the optical transfer function modulus (Modulus of the OTF), the solid line represents the tangential curve, and the dotted line represents the sagittal curve. From the figure, we can see the spatial transfer function of the optical lens in the working band. This is one of the performance parameters of the optical lens in this band and a way to evaluate the resolution of the optical lens. The modulation transfer function (FFT MTF) of each Fourier transform shows the corresponding meridian and sagittal curves of different fields of view. The higher the modulus of the optical transfer function, the clearer the image. Figure 7 and Figure 8 It can be seen that at working distances of 65 mm and 2000 mm, the optical lens provided in this embodiment has very good imaging quality within a large field of view.

[0180] Fig. 9 The axial chromatic aberration diagram of an optical lens provided by an embodiment of the present invention when the working distance is 65 mm, Fig.10 The axial chromatic aberration diagram of an optical lens provided by an embodiment of the present invention when the working distance is 2000 mm, wherein: Fig. 9 The axial chromatic aberration diagram of the optical lens with a working distance of 65 mm at wavelengths of 430 nm, 486 nm, 546 nm, 588 nm and 656 nm is shown. Fig.10 The axial chromatic aberration diagram of the optical lens with a working distance of 2000mm at wavelengths of 430nm, 486nm, 546nm, 588nm and 656nm is shown. Fig. 9 and Fig.10As shown in the figure, the above-mentioned axial chromatic aberrations respectively reflect the imaging aberrations of the optical lens with working distances of 65mm and 2000mm at different wavelengths. The distribution of aberrations at different wavelengths is also an important way to evaluate the overall imaging characteristics of an optical system. From the analysis diagram, the optical lens has achieved good results in correcting chromatic aberrations.

[0181] It should be noted that this embodiment expands the object distance focusing range of the original fixed focal length optical lens to 1935 mm, thereby expanding the use scenarios of the optical lens and saving human resources and overall costs to a great extent.

[0182] In the embodiment of the present invention, the optical lens has a small number of lenses and low cost, the depth of field can reach within the range of 1935mm, the working distance can be between 65mm-2000mm, the magnification can reach more than 90%, it has a wide wavelength range of 430nm-650nm, and the parallax and aberration are small.

[0183] Among them, since the focus position of the optical lens is adjusted in real time by controlling the driving voltage or driving current of the liquid lens, the purpose of fast focusing at different working distances is achieved. The lens does not move during the focusing process, and the stability is better and the focusing speed is faster. At the same time, driving the optical lens does not require the use of driving motors and other equipment. Not only is the overall size smaller, the structure more compact, and the use more convenient, but the cost is also relatively low. It can avoid the problems of high testing cost and low efficiency caused by moving the internal lens of the camera or moving the camera position to meet the testing requirements when testing a large depth of field.

[0184] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0185] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical lens, characterized in that: It includes a first lens group, a liquid lens and a second lens group which are arranged in sequence from the object side to the image side along the optical axis; The first lens group has positive optical power, and the second lens group has positive optical power; The first lens group includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object side to the image side; The second lens group includes a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the object side to the image side; The first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power.

2. The optical lens according to claim 1, characterized in that: The object side surface of the first lens is convex, and the image side surface is concave; The object side surface of the second lens is concave, and the image side surface is concave; The object side surface of the third lens is convex, and the image side surface is convex; The object side surface of the fourth lens is convex, and the image side surface is convex; The object side surface of the fifth lens is convex, and the image side surface is concave; The object side surface of the sixth lens is concave, and the image side surface is convex; The object side surface of the seventh lens is concave, and the image side surface is convex; The object side surface of the eighth lens is convex, and the image side surface is convex; The object side surface of the ninth lens is concave, and the image side surface is convex.

3. The optical lens according to claim 1, characterized in that: The optical lens further includes a diaphragm; The aperture is located in the optical path between the fifth lens and the liquid lens; or, The aperture is located in the optical path between the liquid lens and the sixth lens.

4. The optical lens according to claim 3, characterized in that: The optical lens further comprises a flat glass, and the flat glass is located on the image side of the ninth lens; The distance between the first lens and the second lens on the optical axis is d1; the distance between the second lens and the third lens on the optical axis is d2; the distance between the third lens and the fourth lens on the optical axis is d3; the distance between the fourth lens and the fifth lens on the optical axis is d4; 1.11mm≤d1≤1.31mm; 0.52mm≤d2≤0.72mm; 0.11mm≤d3≤0.31mm; 0.04mm≤d4≤0.24mm; The aperture is located between the fifth lens and the liquid lens, the distance between the fifth lens and the aperture on the optical axis is d5, the distance between the aperture and the liquid lens on the optical axis is d6, the distance between the liquid lens and the sixth lens on the optical axis is d7, the distance between the seventh lens and the eighth lens on the optical axis is d8, and the distance between the ninth lens and the flat glass on the optical axis is d9; 0.55mm≤d5≤0.75mm; 0.05mm≤d6≤0.25mm; 0.55mm≤d7≤0.75mm; 0.12mm≤d8≤0.32mm; 6.02mm≤d9≤6.82mm.

5. The optical lens according to claim 1, characterized in that: The refractive power of the liquid lens is D, -9≤D≤6.

6. The optical lens according to claim 1, characterized in that: The focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and -1≤f4 / f5<0.

7. The optical lens according to claim 1, characterized in that: The distance between the object side surface of the fourth lens and the image side surface of the fourth lens on the optical axis is d10, and the distance between the image side surface of the fifth lens and the object side surface of the liquid lens on the optical axis is d11, 0<d10 / d11≤5.

8. The optical lens according to claim 1, characterized in that: The chief ray angle of the optical lens is greater than or equal to 10° and less than or equal to 15°.

9. The optical lens according to claim 1, characterized in that: The focal length of the second lens is f2, and the focal length of the optical lens is f, -3≤f2 / f<0.

10. The optical lens according to claim 1, characterized in that: The central curvature radius of the object side surface of the second lens is R1, the central curvature radius of the image side surface of the second lens is R2, and 0≤(R1+R2) / (R1-R2)≤1.

22.

11. The optical lens according to claim 1, characterized in that: The sixth lens and the seventh lens form a first cemented lens group; and / or, The eighth lens and the ninth lens form a second cemented lens group.

12. The optical lens according to claim 1, characterized in that: The focal length of the third lens is f3, the focal length of the fourth lens is f4, and 0<f3 / f4≤1.

13. The optical lens according to claim 1, characterized in that: The thickness of the first lens on the optical axis is d12, the total optical length of the optical lens is TTL, and 0<d12 / TTL≤0.

08.

14. The optical lens according to claim 1, characterized in that: The distance between the third lens and the fourth lens on the optical axis is d3, the distance between the object side surface of the fourth lens and the image side surface of the fourth lens on the optical axis is d10, and 0≤d3 / d10≤5.

15. The optical lens according to claim 1, characterized in that: The focal length of the fifth lens is f5, the focal length of the sixth lens is f6, and -20≤f5 / f6<1.

Images