Optical lens, camera module and microscope

Abstract

The embodiment of the invention relates to the technical field of optical imaging, and provides an optical lens, a camera module and a microscope, and the optical lens comprises twelve lenses which are arranged from an image side to an object side. In the direction from the image side to the object side, the lens located at the first position and the lens located at the second position form a first glued lens, and the focal power of the first glued lens is negative; the focal length EFL of the optical lens meets the relational expression: 3.5 < = EFL < = 6.5; the entrance pupil diameter ENTD of the optical lens satisfies the relational expression: 6.6 < = ENTD < = 9.5. The optical lens achieves the purposes of large numerical aperture, long working distance and high resolution.

Description

Technical Field

[0001] The present application relates to the field of optical imaging technology, and in particular to an optical lens, a camera module and a microscope. Background Art

[0002] Microscopes have important applications in many fields such as biology, medicine, materials science, and nanotechnology. With the improvement of the requirements for observation resolution, imaging speed, and working distance in the field of industrial semiconductor inspection, the performance of microscope objectives has gradually improved, and microscope objectives have gradually tended to develop in the direction of larger field of view, larger numerical aperture, and safer working distance. To improve the clarity of the microscope, the magnification of the microscope objective can be increased, and the numerical aperture can be increased. However, a larger magnification usually means a shorter focal length, and a large numerical aperture usually has a shorter working distance, which is inconvenient to use in many occasions. Summary of the invention

[0003] The embodiments of the present application provide an optical lens and a camera module for solving the problem that the microscope objective lens in the related art cannot have a large numerical aperture, a long working distance and a high resolution at the same time.

[0004] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0005] In a first aspect, an embodiment of the present application provides an optical lens for use in a microscope, the optical lens comprising twelve lenses; from the image side to the object side, the lens located at the first position and the lens located at the second position form a first cemented lens, and the optical focal length of the first cemented lens is negative; the focal length EFL of the optical lens satisfies the relationship: 3.5≤EFL≤6.5; the entrance pupil diameter ENTD of the optical lens satisfies the relationship: 6.6≤ENTD≤9.5.

[0006] In some embodiments, the total optical length TTL of the optical lens satisfies the relationship: TTL≤68mm.

[0007] In some embodiments, the curvature radius R of the image side surface of the lens located at the last position arranged from the image side to the object side is 12A The radius of curvature R of the side surface 12B Satisfy the relationship: 0.267≤R 12A / R 12B ≤0.514.

[0008] In some embodiments, the combined focal length F of the three lenses at the last three positions arranged from the image side to the object side is 10_11_12 The focal length EFL of the optical lens satisfies the relationship: 1.26≤F 10_11_12 / EFL≤2.1.

[0009] In some embodiments, the maximum aperture D of the optical lens MAX With minimum diameter D MIN The absolute value of satisfies the relationship: 1.809<|D MAX / D MIN |<2.5.

[0010] In some embodiments, the optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from the image side to the object side; the first lens and the second lens constitute the first cemented lens, the third lens, the fourth lens and the fifth lens constitute the second cemented lens, and the sixth lens and the seventh lens constitute the third cemented lens.

[0011] In some embodiments, the optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from the image side to the object side; the first lens is a biconvex lens with positive optical power, the second lens is a biconcave lens with negative optical power, the third lens is a biconvex lens with positive optical power, the fourth lens is a biconcave lens with negative optical power, the fifth lens is a biconvex lens with positive optical power, the sixth lens is a biconvex lens with positive optical power, the seventh lens is a meniscus lens or a biconcave lens with negative optical power, the eighth lens is a biconvex lens with positive optical power, the ninth lens is a biconcave lens with negative optical power, the tenth lens is a biconvex lens with positive optical power, the eleventh lens is a meniscus lens with positive optical power, and the twelfth lens is a meniscus lens with positive optical power.

[0012] In some embodiments, the optical power of the second cemented lens is negative, and the optical power of the third cemented lens is positive.

[0013] In some embodiments, the optical lens further includes a stop, and the stop is located between the ninth lens and the tenth lens.

[0014] In some embodiments, the optical lens further includes a cover glass, and the cover glass is located on a side of the twelfth lens close to the object plane.

[0015] Among the twelve lenses of the optical lens in the embodiment of the present application, from the image side to the object side, the lens located at the first position and the lens located at the second position form a first cemented lens, that is, the first position close to the image side is the first cemented lens, and the optical focal length of the first cemented lens is negative, forming a reverse telephoto structure. At the same time, on this basis, on the one hand, by reasonably selecting and designing the entrance pupil diameter of the optical lens, the numerical aperture can be appropriately reduced, thereby achieving the purpose of taking into account both a large numerical aperture and a long working distance; on the other hand, the design of the first cemented lens reduces the tolerance sensitivity of the optical lens. At the same time, the optical focal length of each lens is reasonably selected, so that when the focal length of the optical lens satisfies the above relationship, it is beneficial to reduce the aberration of the optical lens, thereby facilitating the improvement of the resolution of the optical lens, thereby enabling the optical lens to achieve the purpose of taking into account both a large numerical aperture, a long working distance and a high resolution.

[0016] In a second aspect, an embodiment of the present application provides a microscope comprising the optical lens as described in the first aspect.

[0017] The optical lens in the microscope of the embodiment of the present application has the same structure and technical effects as the optical lens in the first aspect, and will not be described in detail here.

[0018] In a third aspect, an embodiment of the present application provides a camera module, comprising a photosensitive element and the optical lens described in the first aspect, wherein the photosensitive element is arranged on the image side of the optical lens.

[0019] The optical lens in the camera module of the embodiment of the present application has the same structure and technical effects as the optical lens in the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of an optical lens provided in Example 1 of the present application;

[0021] Figure 2 This is the MTF diagram of the optical lens provided in Example 1 of the present application;

[0022] Figure 3 A distortion diagram of the optical lens provided in Example 1 of the present application;

[0023] Figure 4 A schematic diagram of the structure of an optical lens provided in Example 2 of the present application;

[0024] Figure 5 This is the MTF diagram of the optical lens provided in Example 2 of the present application;

[0025] Figure 6 A distortion diagram of the optical lens provided in Example 2 of the present application;

[0026] Figure 7 A schematic diagram of the structure of an optical lens provided in Embodiment 3 of the present application;

[0027] Figure 8 This is the MTF diagram of the optical lens provided in Example 3 of the present application;

[0028] Fig. 9 This is a distortion diagram of the optical lens provided in Example 3 of the present application.

[0029] Among them, the reference numerals in the figure are:

[0030] The first cemented lens J1; the second cemented lens J2; the third cemented lens J3; the fourth cemented lens J4;

[0031] A first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, an eleventh lens L11, a twelfth lens L12, a cover glass L20, and an aperture stop STOP. DETAILED DESCRIPTION

[0032] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of the present application are explained and described below.

[0033] Focal power is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam. It characterizes the ability of an optical lens to deflect light.

[0034] The optical power of the lens or lens group is positive, and the lens or lens group has a positive focal length, which has the effect of converging light.

[0035] The optical power of the lens or lens group is negative, and the lens or lens group has a negative focal length, which has the effect of diverging light.

[0036] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical lens. It refers to the vertical distance from the optical center of a lens or lens group to the focal plane when an infinitely distant scene forms a clear image on the focal plane through the lens or lens group. For a fixed-focus lens, the position of its optical center is fixed; for a telephoto lens, the change of the optical center of the lens brings about a change in the focal length of the lens.

[0037] The effective focal length (EFL) of a lens refers to the distance from the center of the lens to the focus.

[0038] The composite focal length is the combination of the focal lengths of the individual lenses in the lens group.

[0039] The object side is bounded by the lens. The side where the object is located is called the object side, and the surface of the lens close to the object side is called the object side.

[0040] The image side is bounded by the lens. The side where the image of the object is located is called the image side, and the surface of the lens close to the image side is called the image side.

[0041] The aperture (aperture diaphragm) is a device used to control the amount of light that passes through the lens and enters the photosensitive surface inside the camera body. It is usually inside the lens.

[0042] The object plane is located on the object side of all lenses in the optical lens and is the surface on which the object to be photographed is placed.

[0043] The optical axis is an axis that passes vertically through the center of the lens. The optical axis of the lens is the axis that passes through the center of each lens of the lens.

[0044] Focus is the point where parallel light rays converge after being refracted by a lens or lens group.

[0045] The Abbe number, or dispersion coefficient, is the difference ratio of the refractive index of an optical material at different wavelengths, representing the degree of dispersion of the material.

[0046] Aberration: An optical lens has the properties of an ideal optical system at the optical axis. The near-axis light emitted from a point on the object intersects the image plane at one point (also known as the optical axis image point). However, the light rays that actually pass through the lens with different apertures are difficult to intersect perfectly at one point, but have a certain deviation from the position of the near-axis image point. These differences are collectively called aberrations.

[0047] Distortion, also known as distortion, is the degree of distortion of the image formed by an optical lens relative to the object itself. Distortion is due to the influence of aperture spherical aberration. The height of the intersection of the main light of different fields of view with the Gaussian image plane after passing through the optical lens is not equal to the ideal image height. The difference between the two is the distortion.

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] In the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "plurality" means two or more.

[0050] like Figure 1 , Figure 4 and Figure 7 As shown, an embodiment of the present application provides a microscope, including an optical lens.

[0051] The above optical lens may be, but is not limited to, an objective lens of a microscope.

[0052] like Figure 1 As shown, the optical lens includes twelve lenses; from the image side to the object side, the lens at the first position (such as Figure 1 The first lens L1 in the figure and the lens at the second position (such as Figure 1 The second lens L2 in the middle forms a first cemented lens J1, and the optical power of the first cemented lens J1 is negative.

[0053] Among the twelve lenses of the optical lens in the embodiment of the present application, from the image side to the object side, the lens located at the first position and the lens located at the second position form a first cemented lens, that is, the first position close to the image side is the first cemented lens, and the optical focal length of the first cemented lens is negative, forming a reverse telephoto structure, which can not only well extend the working distance, but also reduce the tolerance sensitivity of the optical lens. At the same time, by reasonably allocating the optical focal length of the twelve lenses, the aberration of the optical lens can be made smaller, which is more conducive to improving the resolution. In addition, it is convenient to assemble the optical lens.

[0054] It should be noted that the above optical lens is a semi-closed wireless optical conjugate system, which is a type of wireless conjugate system. When parallel light rays are transmitted from the image side to the object side through the optical lens to the object plane, the light rays on the side close to the object plane converge on the object plane, that is, the light rays close to the object plane are closed, and the light rays close to the image side are wireless, so it is called a semi-closed wireless optical conjugate system.

[0055] During the design process of the above-mentioned optical lenses, the main optical parameters are more important.

[0056] In the embodiment of the present application, the focal length EFL of the optical lens satisfies the relationship: 3.5≤EFL≤6.5.

[0057] By rationally selecting the optical power of each lens, when the focal length of the optical lens satisfies the above relationship, it is helpful to reduce the aberration of the optical lens, thereby helping to improve the resolution of the optical lens.

[0058] The entrance pupil diameter ENTD of the optical lens satisfies the relationship: 6.6≤ENTD≤9.5.

[0059] The smaller the entrance pupil diameter ENTD is, the smaller the numerical aperture NA is, and the larger the working distance is.

[0060] By rationally selecting and designing the entrance pupil diameter of the optical lens, the numerical aperture can be appropriately reduced, thereby achieving the goal of both a large numerical aperture and a long working distance.

[0061] In addition, the F number and relative aperture of the optical lens are also related to the focal length EFL and the entrance pupil diameter ENTD mentioned above. Therefore, by reasonably selecting the two optical parameters of the focal length EFL and the entrance pupil diameter ENTD mentioned above, the F number and relative aperture of the optical lens can also be reasonably selected accordingly so that the performance of the optical lens meets the requirements.

[0062] Therefore, in summary, the optical lens achieves the goal of large numerical aperture, long working distance and high resolution.

[0063] In some embodiments, the total optical length TTL of the optical lens satisfies the relationship: TTL≤68mm.

[0064] Through the above settings, the optical lens can be matched with different tube lenses to achieve different magnifications, and the length of the system can be adjusted according to actual needs in combination with the tube lens.

[0065] In some embodiments, the lens located at the last position arranged from the image side to the object side (eg Figure 1 The curvature radius R of the image side surface of the twelfth lens L12) 12A The radius of curvature R of the side surface 12B Satisfy the relationship: 0.267≤R 12A / R 12B ≤0.514.

[0066] When the above ratio is relatively small, the field curvature of the optical lens is corrected, but the aberration is not well corrected; when the above ratio is relatively large, not only the processing difficulty of the twelfth lens L12 is increased and the coating is not good, but also the aberration of the optical lens is increased.

[0067] When the above relationship is satisfied, not only the processing difficulty of the twelfth lens L12 is reduced, and coating is convenient, but also the aberration is reduced, which is beneficial to improving the resolution.

[0068] In some embodiments, the three lenses arranged from the image side to the object side at the last three positions (eg, Figure 1The combined focal length F of the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 10_11_12 The focal length EFL of the optical lens satisfies the relationship: 1.26≤F 10_11_12 / EFL≤2.1.

[0069] The above F 10_11_12 It is the combined focal length of the last three lenses arranged from the image side to the object side in the optical lens, that is, the sum of the focal lengths of the tenth lens L10, the eleventh lens L11 and the twelfth lens L12.

[0070] When the above F 10_11_12 When the combined focal length F of the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 is smaller, that is, 10_11_12 is relatively small and difficult to achieve; when the above F 10_11_12 When the combined focal length F of the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 is larger, that is, 10_11_12 If it is relatively large, it will cause the length of the optical lens to be longer, which is not conducive to the miniaturization design of the optical lens.

[0071] When the above ratios satisfy the above relationship, the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 are sequentially arranged in close contact, so that the optical lens can reduce the length of the optical lens while meeting the optical requirements, thereby facilitating the miniaturization design of the optical lens.

[0072] It should be noted that, closely contacting one another means that the gap between two adjacent lenses is small.

[0073] In some embodiments, the maximum aperture D of the optical lens MAX With minimum diameter D MIN The absolute value of satisfies the relationship: 1.809<|D MAX / D MIN |<2.5.

[0074] When |D MAX / D MIN | is too small, making the overall aperture of the optical lens more uniform, but increasing the difficulty of optical lens design; when |D MAX / D MIN |When it is too large, the difference between the maximum and minimum apertures of the optical lens is relatively large, resulting in a larger overall volume of the optical lens.

[0075] When the maximum aperture of the optical lens is D MAX With minimum diameter D MINWhen the absolute value of satisfies the above relationship, the optical lens reduces the difference between the maximum and minimum apertures of the optical lens on the basis of meeting the optical requirements, that is, the overall aperture of the optical lens is relatively uniform. In this way, when the optical lens is placed in the lens barrel, the space utilization rate in the lens barrel is relatively high, thereby achieving the purpose of taking into account the miniaturization design of the optical lens and improving the space utilization rate of the lens barrel where the optical lens is placed.

[0076] Figure 1 The structure diagram of the optical lens of the first embodiment is shown. The optical lens comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a stop STOP, a tenth lens L10, an eleventh lens L11, a twelfth lens L12 and a cover glass L20 arranged in sequence from the image side to the object side; the first lens L1 and the second lens L2 form a first cemented lens J1, the third lens L3, the fourth lens L4 and the fifth lens L5 form a second cemented lens J2, and the sixth lens L6 and the seventh lens L7 form a third cemented lens J3; the optical power of the first cemented lens J1 is negative, the optical power of the second cemented lens J2 is negative, and the optical power of the third cemented lens J3 is positive.

[0077] In the embodiment of the present application, the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 are in close contact with each other in sequence. The specific distances between the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 are shown in Table 1a.

[0078] Table 1a to Table 1d respectively give specific parameter values ​​of each lens of an optical lens of an optional embodiment in Example 1 of the present application.

[0079] Table 1a

[0080] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 35.413 1.778 1.922859 20.8846 Sur2 Standard -18.619 1 1.58599 64.5999 Sur3 Standard 7.636 20.548 Sur4 Standard 32.784 3.784 1.497 81.6128 Sur5 Standard -10.985 1 2.00069 25.4258 Sur6 Standard 17.027 4.081 1.5928 68.342 Sur7 Standard -22.017 0.1 Sur8 Standard 37.268 6.362 1.5928 68.342 Sur9 Standard -11.096 1 1.497 81.6128 Sur10 Standard -92.042 0.1 STOP Standard 17.265 5.562 1.5928 68.342 Sur12 Standard -21.76 1 1.672707 32.181 Sur13 Standard 14.115 2.778 Sur14 Standard Infinity 0.1 Sur15 Standard 37.413 2.47 1.922859 20.8846 Sur16 Standard -65.41 0.1 Sur17 Standard 12.854 2.583 1.755 52.3001 Sur18 Standard 25.897 0.1 Sur19 Standard 7.459 3.618 1.755 52.3001 Sur20 Standard 17.455 1.136 Sur21 Standard Infinity 0.7 1.501371 56.4092 Sur22 Standard Infinity 0.1 1.4645 65.7687 Sur23 Standard Infinity 3.05

[0081] It should be noted that in Table 1a, "Surface Number" is the number of each surface arranged in sequence from the object side to the image side, the radius R value is the lens with the corresponding surface number, that is, the curvature radius of the object side or image side of the lens corresponding to each surface number at the optical axis, and the "Infinity" in the "Curvature Radius" parameter series of the lens means that the object side or image side of the lens is a plane; the value of "Sur23" at "Thickness" is the working distance of the optical lens.

[0082] The optical parameters of the optical lens in Example 1 and the relationship they satisfy are shown in Table 1b.

[0083] Table 1b

[0084] parameter Numerical aperture Object side field of view CRA angle Working distance Numeric 0.8 0.25 0.8 3.05mm parameter EFL ENTD TTL Numeric 4.486mm 8.589mm 63.05mm Relational <![CDATA[R 12A / R 12B ]]> <![CDATA[D MAX / D MIN ]]> <![CDATA[F 10_11_12 / EFL]]> Numeric 0.427 2.022 1.677

[0085] Note: The following are the explanations of the relationship between the optical lenses in each embodiment:

[0086] EFL is the focal length of the optical lens;

[0087] ENTD is the entrance pupil diameter of the optical lens;

[0088] TTL is the total optical length of the optical lens;

[0089] F 10_11_12 It is the combined focal length of the last three lenses arranged from the image side to the object side in the optical lens, that is, the sum of the focal lengths of the tenth lens L10, the eleventh lens L11 and the twelfth lens L12;

[0090] R 12A is the curvature radius of the image side surface of the last lens arranged from the image side to the object side in the optical lens, that is, the curvature radius of the image side surface of the twelfth lens L12;

[0091] R 12B is the curvature radius of the object side surface of the last lens arranged from the image side to the object side in the optical lens; that is, the curvature radius of the object side surface of the twelfth lens L12;

[0092] The Chinese meaning of CRA (Chief Ray Angle) is "chief ray angle". In optical lens design, CRA refers to the maximum angle of light that can be focused on a pixel on one side of the optical lens sensor. The pixel responsivity at this angle is 80% of the pixel responsivity at zero degree angle.

[0093] The positive and negative conditions of the focal length of each lens in the optical lens of Example 1 are shown in Table 1c.

[0094] Table 1c

[0095]

[0096] It should be noted that the "+" and "-" in Table 1c represent the positive and negative conditions of the focal length of each lens in the optical lens in Example 1. Among them, "+" represents that the focal length of the lens is positive; "-" represents that the focal length of the lens is negative.

[0097] The concave-convex condition of the object side surface or image side surface of each lens in the optical lens of Example 1 at the optical axis is shown in Table 1d.

[0098] Table 1d

[0099]

[0100] It should be noted that the "-+", "+-", and "--" in Table 1d represent the concave-convex situation of the object side or image side of each lens at the optical axis. Among them, "-+" represents that the object side of the lens is concave toward the object side at the optical axis, and the image side is convex toward the object side at the optical axis; "+-" represents that the object side of the lens is convex toward the object side at the optical axis, and the image side is convex toward the object side at the optical axis, that is, a double convex structure; "--" represents that both the object side and the image side of the lens are concave toward the object side at the optical axis. Of course, in addition to the above-mentioned concave and convex conditions, each lens in the optical lens may also include any one or more of "++", "∞+", "+∞", "∞-", and "-∞". "++" represents that both the object side and the image side of the lens are convex toward the object side at the optical axis; "∞+" represents that the object side of the lens is a plane at the optical axis, and the image side is convex toward the object side at the optical axis; "+∞" represents that the object side of the lens is convex toward the object side at the optical axis, and the image side is a plane at the optical axis; among them, "∞-" represents that the object side of the lens is a plane at the optical axis, and the image side is concave toward the object side at the optical axis; "-∞" represents that the object side of the lens is concave toward the object side at the optical axis, and the image side is a plane at the optical axis, and no specific limitation is made here.

[0101] Combination Figure 1 From the structural schematic diagram of the optical lens in Example 1 and the main parameters of the optical lens in Example 1 given in Tables 1a, 1c and 1d, it can be obtained that the first lens in the optical lens in this embodiment is a biconvex lens with positive focal power, the second lens is a biconcave lens with negative focal power, the third lens is a biconvex lens with positive focal power, the fourth lens is a biconcave lens with negative focal power, the fifth lens is a biconvex lens with positive focal power, the sixth lens is a biconvex lens with positive focal power, the seventh lens is a meniscus lens with negative focal power, the eighth lens is a biconvex lens with positive focal power, the ninth lens is a biconcave lens with negative focal power, the tenth lens is a biconvex lens with positive focal power, the eleventh lens is a meniscus lens with positive focal power, and the twelfth lens is a meniscus lens with positive focal power.

[0102] In the optical lens of the first embodiment, the refractive powers of the first lens L1, the third lens L3 and the fifth lens L5 are positive.

[0103] The refractive index nd of the first lens L1 L1 is 1.922859, the Abbe number vd L1 It is 20.8846.

[0104] The refractive index nd of the third lens L3 L3 is 1.497, the Abbe number vd L3 It is 81.6128.

[0105] The refractive index nd of the fifth lens L5 L5 is 1.5928, the Abbe number vdL5 It is 68.342.

[0106] Combination Figure 1 The structural diagram of the optical lens in the first embodiment, and the main parameters of the optical lens in the first embodiment given in Tables 1a to 1d satisfy the relationship in Table 1b, and the concave-convex condition of each lens at the optical axis. The MTF diagram and distortion diagram of the optical lens in the first embodiment obtained by simulation are as follows: Figure 2 and Figure 3 shown.

[0107] in: Figure 2 The MTF diagram of the optical lens provided in Example 1 of the present application. MTF is the abbreviation of Modulation Transfer Function in English, which means that the function of modulation degree changing with spatial frequency is called modulation degree transfer function. The MTF diagram is a curve diagram reflecting the restoration of contrast (reduction degree) by the optical lens. The horizontal axis of the MTF diagram is the distance from the center to the edge, and the vertical axis of the MTF diagram reflects the quality of the contrast, or the quality of the reduction degree.

[0108] Figure 3 This is a distortion diagram of the optical lens provided in Example 1 of the present application. The distortion diagram represents the distortion percentage of the optical lens as the field of view changes, wherein the horizontal axis represents the distortion percentage and the vertical axis represents the normalized field of view height.

[0109] The above descriptions about the MTF graph and the distortion graph are the same as those in other embodiments and will not be repeated hereinbelow.

[0110] from Figure 2 It can be seen that the MTF of the 0-1.0 field of view lens at 100lp / mm, 200lp / mm, 300lp / mm and 400lp / mm is greater than 0.6, indicating that the optical lens has a good degree of restoration, high resolution and excellent imaging.

[0111] from Figure 3 It can be seen that the distortion of the optical lens is less than 0.02%.

[0112] Figure 4 The structure diagram of the optical lens of the second embodiment is shown. The main difference between the optical lens of the second embodiment and the optical lens of the first embodiment is the structure of the seventh lens, and the parameters of each lens and the conditions they meet are different.

[0113] Tables 2a to 2d respectively give specific parameter values ​​of each lens of an optical lens of an optional embodiment in Example 2 of the present application.

[0114] Table 2a

[0115] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 75.522 2.605 1.94595 17.942 Sur2 Standard -20.906 2.776 1.497 81.6128 Sur3 Standard 7.358 24.832 Sur4 Standard 31.451 2.998 1.5928 68.342 Sur5 Standard -12.62 1 1.92286 20.8799 Sur6 Standard 16.588 3.289 1.437001 95.1004 Sur7 Standard -19.233 0.1 Sur8 Standard 14.023 4.015 1.617998 63.4058 Sur9 Standard -24.097 1.113 1.497 81.6128 Sur10 Standard 28.381 1.524 STOP Standard 12.313 3.944 1.570989 50.7999 Sur12 Standard -18.002 1.015 1.699678 34.9255 Sur13 Standard 8.651 2.13 Sur14 Standard Infinity 0.1 Sur15 Standard 27.289 1.868 1.92286 20.8799 Sur16 Standard -54.33 0.1 Sur17 Standard 9.386 1.704 1.92286 20.8799 Sur18 Standard 13.015 0.1 Sur19 Standard 6.325 3.388 1.755 52.3221 Sur20 Standard 19.943 0.598 Sur21 Standard Infinity 0.7 1.501371 56.4092 Sur22 Standard Infinity 0.1 1.4645 65.7687 Sur23 Standard Infinity 2.8

[0116] The optical parameters of the optical lens in Example 2 and the relationship they satisfy are shown in Table 2b.

[0117] Table 2b

[0118] parameter Numerical aperture Object side field of view CRA angle Working distance Numeric 0.73 0.24 0.92 2.8mm parameter EFL ENTD TTL Numeric 4.532mm 7.1mm 62.779mm Relational <![CDATA[R 12A / R 12B ]]> <![CDATA[D MAX / D MIN ]]> <![CDATA[F 10_11_12 / EFL]]> Numeric 0.317 1.809 1.315

[0119] The optical power of each lens of the optical lens in Example 2 is shown in Table 2c.

[0120] Table 2c

[0121]

[0122] The concave-convex condition of the object side surface or image side surface of each lens of the optical lens in Example 2 at the optical axis is shown in Table 2d.

[0123] Table 2d

[0124]

[0125] Combination Figure 4 From the structural diagram of the optical lens in the second embodiment and the main parameters of the optical lens in the first embodiment given in Tables 2a, 2c and 2d, it can be obtained that the seventh lens in the optical lens in this embodiment is a double concave lens with negative optical power. In this embodiment, the number of lenses is the same as that of the lenses in the first embodiment, except that the structure and optical power of the seventh lens L7 are different from those in the first embodiment, the rest of the optical power and concave-convex conditions of the lenses are the same as those in the first embodiment, and no further description is given here.

[0126] In the optical lens of the second embodiment, the refractive powers of the first lens L1, the third lens L3 and the fifth lens L5 are positive.

[0127] The refractive index nd of the first lens L1 L1 is 1.94595, the Abbe number vd L1 It is 17.942.

[0128] The refractive index nd of the third lens L3 L3 is 1.5928, the Abbe number vd L3 It is 68.342.

[0129] The refractive index nd of the fifth lens L5 L5 is 1.437001, the Abbe number vd L5 It is 95.1004.

[0130] Combination Figure 4The structural diagram of the optical lens in the second embodiment, and the main parameters of the optical lens in the second embodiment given in Tables 2a to 2d satisfy the relationship in Table 2b, and the concave-convex condition of each lens at the optical axis. The MTF diagram and distortion diagram of the optical lens in the second embodiment obtained by simulation are as follows: Figure 5 and Figure 6 shown.

[0131] from Figure 5 It can be seen that the MTF of the 0-1.0 field of view lens at 100lp / mm, 200lp / mm, 300lp / mm and 400lp / mm is greater than 0.5, indicating that the optical lens has a good degree of restoration, high resolution and excellent imaging.

[0132] from Figure 6 It can be seen that the distortion of the optical lens is less than 0.08%.

[0133] Figure 7 The structure diagram of the optical lens of the third embodiment is shown. In this embodiment, the number and frame of the lenses in the optical lens are the same as those in the first embodiment, and the main difference between the optical lens in the third embodiment and the optical lens in the first embodiment is that the parameters of each lens and the conditions to be satisfied are different.

[0134] Tables 3a to 3d respectively give specific parameter values ​​of each lens of an optical lens of an optional embodiment in Example 3 of the present application.

[0135] Table 3a

[0136] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 44.772 1.692 1.92286 20.8799 Sur2 Standard -22.315 1 1.437001 95.1004 Sur3 Standard 7.475 27.727 Sur4 Standard 51.775 2.597 1.60625 63.711 Sur5 Standard -10.468 1 1.92286 20.8799 Sur6 Standard 15.448 2.727 1.525005 70.3302 Sur7 Standard -21.292 4 Sur8 Standard 17.947 4.57 1.613091 60.3837 Sur9 Standard -10.997 1 1.497003 81.1382 Sur10 Standard 43.125 0.1 STOP Standard 19.769 3.864 1.58286 59.5046 Sur12 Standard -10.607 2.981 1.728277 28.5326 Sur13 Standard 13.05 1.647 Sur14 Standard Infinity 0.375 Sur15 Standard 60.905 1.897 1.92286 20.8799 Sur16 Standard -25.363 0.487 Sur17 Standard 10.791 1.704 1.92286 20.8799 Sur18 Standard 17.801 0.1 Sur19 Standard 5.859 3.022 1.72903 54.0413 Sur20 Standard 14.966 0.709 Sur21 Standard Infinity 0.7 1.501371 56.4092 Sur22 Standard Infinity 0.1 1.4645 65.7687 Sur23 Standard Infinity 2.68

[0137] The optical parameters of the optical lens in Example 3 and the relationship they satisfy are shown in Table 3b.

[0138] Table 3b

[0139] parameter Numerical aperture Object side field of view CRA angle Working distance Numeric 0.69 0.27 0.5 2.68mm parameter EFL ENTD TTL Numeric 4.79mm 8.81mm 66.679mm Relational <![CDATA[R 12A / R 12B ]]> <![CDATA[D MAX / D MIN ]]> <![CDATA[F 10_11_12 / EFL]]> Numeric 0.391 1.556 1.222

[0140] The optical power of each lens of the optical lens in Example 3 is shown in Table 3c.

[0141] Table 3c

[0142]

[0143] The concave-convex condition of the object side surface or image side surface of each lens of the optical lens in Example 3 at the optical axis is shown in Table 3d.

[0144] Table 3d

[0145]

[0146] In the optical lens of the third embodiment, the refractive powers of the first lens L1, the third lens L3 and the fifth lens L5 are positive.

[0147] The refractive index nd of the first lens L1 L1 is 1.92286, the Abbe number vd L1 It is 20.8799.

[0148] The refractive index nd of the third lens L3 L3 is 1.60625, the Abbe number vd L3 It is 63.711.

[0149] The refractive index nd of the fifth lens L5 L5 is 1.525005, the Abbe number vd L5 It is 70.3302.

[0150] Combination Figure 7 The schematic diagram of the structure of the optical lens in the third embodiment, and the main parameters of the optical lens in the third embodiment given in Tables 3a to 3d satisfy the relationship in Table 3b, and the concave-convex condition of each lens at the optical axis. The MTF diagram and distortion diagram of the optical lens in the third embodiment obtained by simulation are as follows: Figure 8 and Fig. 9 shown.

[0151] from Figure 8 It can be seen that the MTF of the 0-1.0 field of view lens at 100lp / mm, 200lp / mm, 300lp / mm and 400lp / mm is greater than 0.65, indicating that the optical lens has a good degree of restoration, high resolution and excellent imaging.

[0152] from Fig. 9 It can be seen that the distortion of the optical lens is less than 0.05%.

[0153] In summary, when the optical lens of the present application is used as a microscope objective lens, the numerical aperture of the optical lens can reach 0.8, the maximum working distance can reach 4.4 mm, and the maximum object field angle can reach 0.3. Combined with the MTF graphs and distortion graphs in the above three embodiments, it can be shown that the optical lens achieves the purpose of taking into account a large numerical aperture, a long working distance and a high resolution. That is, the microscope can also achieve the purpose of taking into account a large numerical aperture, a long working distance and a high resolution.

[0154] Embodiment 4 of the present application further provides a camera module, which includes an optical lens and a photosensitive element (not shown in the figure), and the photosensitive element is located on the image side of the optical lens.

[0155] The working principle of the camera module is as follows: the light reflected by the photographed scene generates an optical image through the optical lens and is projected onto the photosensitive surface of the photosensitive element. The photosensitive element converts the optical image into an electrical signal, namely an analog image signal, and transmits it to the processor.

[0156] Among them, the photosensitive element (also called image sensor) is a semiconductor chip with hundreds of thousands to millions of photodiodes on its surface. When exposed to light, it will generate electric charge. The photosensitive element can be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). CCD is made of a highly sensitive semiconductor material that can convert light into electric charge. Charge coupled devices are composed of many photosensitive units, usually in units of millions of pixels. When the surface of the photosensitive element is exposed to light, each photosensitive unit will reflect the charge on the component, and the signals generated by all the photosensitive units are added together to form a complete picture.

[0157] Among them, the camera module mainly uses the refraction principle of the lens to form an image, that is, the light of the scene passes through the optical lens to form a clear image on the focal plane, and the image of the scene is recorded through the photosensitive element located on the focal plane.

[0158] In this embodiment, the structure of the optical lens is the same as the structure of the optical lens in the above-mentioned embodiments 1 to 3 and the effects obtained are the same, and will not be described in detail here.

[0159] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical lens, applied to a microscope, characterized in that: The optical lens comprises twelve lenses; From the image side to the object side, the lens at the first position and the lens at the second position form a first cemented lens, and the optical power of the first cemented lens is negative; The focal length EFL of the optical lens satisfies the relationship: 3.5≤EFL≤6.5; The entrance pupil diameter ENTD of the optical lens satisfies the relationship: 6.6≤ENTD≤9.

5.

2. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens satisfies the relationship: TTL≤68mm.

3. The optical lens according to claim 1, characterized in that: The curvature radius R of the image side surface of the lens located at the last position arranged from the image side to the object side 12A The radius of curvature R of the side surface 12B Satisfy the relationship: 0.267≤R 12A / R 12B ≤0.

514.

4. The optical lens according to claim 1, characterized in that: The combined focal length F of the three lenses at the last three positions arranged from the image side to the object side is 10_11_12 The focal length EFL of the optical lens satisfies the relationship: 1.26≤F 10_11_12 / EFL≤2.

1.

5. The optical lens according to claim 1, characterized in that: The maximum aperture D of the optical lens MAX With minimum diameter D MIN The absolute value of satisfies the relationship: 1.809<|D MAX / D MIN |<2.

5.

6. The optical lens according to any one of claims 1 to 5, characterized in that: The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from the image side to the object side; the first lens and the second lens constitute the first cemented lens, the third lens, the fourth lens and the fifth lens constitute the second cemented lens, and the sixth lens and the seventh lens constitute the third cemented lens.

7. The optical lens according to any one of claims 1 to 5, characterized in that: The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from the image side to the object side; the first lens is a biconvex lens with positive optical power, the second lens is a biconcave lens with negative optical power, the third lens is a biconvex lens with positive optical power, the fourth lens is a biconcave lens with negative optical power, the fifth lens is a biconvex lens with positive optical power, the sixth lens is a biconvex lens with positive optical power, the seventh lens is a meniscus lens or a biconcave lens with negative optical power, the eighth lens is a biconvex lens with positive optical power, the ninth lens is a biconcave lens with negative optical power, the tenth lens is a biconvex lens with positive optical power, the eleventh lens is a meniscus lens with positive optical power, and the twelfth lens is a meniscus lens with positive optical power.

8. The optical lens according to claim 6, characterized in that: The optical power of the second cemented lens is negative, and the optical power of the third cemented lens is positive.

9. The optical lens according to claim 6, characterized in that: The optical lens further includes a stop, and the stop is located between the ninth lens and the tenth lens.

10. The optical lens according to claim 6, characterized in that: The optical lens also includes a cover glass, and the cover glass is located on a side of the twelfth lens close to the object plane.

11. A microscope, characterized in that: include: The optical lens according to any one of claims 1 to 10.

12. A camera module, characterized in that: include: The optical lens according to any one of claims 1 to 10; A photosensitive element is arranged on the image side of the optical lens.

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