Lens and line scanning detection device

Abstract

The invention provides a lens and a line scanning detection device. The lens comprises a first lens group with positive focal power, a diaphragm and a second lens group with negative focal power which are sequentially arranged from an object side to an image side, the first lens group comprises a first positive focus lens group, the first positive focus lens group is located on one side, close to the diaphragm, of the first lens group, and the first positive focus lens group at least comprises a positive lens; the second lens group comprises a second positive focus lens group, the second positive focus lens group is located on the side, close to the diaphragm, of the second lens group, and the second positive focus lens group at least comprises one positive lens. The lens provided by the invention is beneficial to correcting off-axis aberration and reducing distortion, and enables the image quality to be uniform in a multiplying power range at the same time.

Description

Technical Field

[0001] The present application belongs to the field of optical lenses, and more specifically, to a lens and a line scanning detection device. Background Art

[0002] Scanning detection devices are widely used in a variety of industrial inspections and service industries such as textile inspection, QR code and railway inspection. The lens is a key component in the scanning detection device. The current scanning detection device lens has large distortion and uneven image quality within the magnification range. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a lens and a line scan detection device to solve the technical problems existing in the prior art such as large lens distortion and uneven image quality within a magnification range.

[0004] To achieve the above object, the technical solution adopted by the present application is: to provide a lens, the lens comprising a first lens group with positive focal power, an aperture, and a second lens group with negative focal power, arranged in sequence from the object side to the image side;

[0005] The first lens group includes a first positive focus lens group, the first positive focus lens group is located at a side of the first lens group close to the aperture, and the first positive focus lens group includes at least one positive lens;

[0006] The second lens group includes a second positive focus lens group, the second positive focus lens group is located at a side of the second lens group close to the aperture, and the second positive focus lens group includes at least one positive lens.

[0007] Optionally, the first lens group includes a first spherical meniscus positive lens close to the object side, the first spherical meniscus positive lens is convex toward the object side, and the focal length of the first spherical meniscus positive lens satisfies the condition: f1 / f>0.42, wherein f1 is the focal length of the first spherical meniscus positive lens, and f is the focal length of the lens.

[0008] Optionally, the first lens group includes at least one first cemented lens, the first cemented lens is located on a side of the first spherical meniscus positive lens close to the image side, the first cemented lens includes a positive lens and a negative lens, and the refractive index and Abbe number of the positive lens and the negative lens in the first cemented lens satisfy: vd p -vd n >20; and nd n -nd p >0.1;

[0009] Among them, vd p is the Abbe number of the positive lens of the first doublet, nd p is the refractive index of the positive lens of the first cemented lens, vd n is the Abbe number of the negative lens of the first doublet, nd nis the refractive index of the negative lens of the first cemented lens.

[0010] Optionally, the first positive focus lens group is located on a side of the first cemented lens close to the aperture, and the first positive focus lens group satisfies the condition: 0.4<fU1 / f<1.8, wherein fU1 is the focal length of the first positive focus lens group, and f is the focal length of the lens.

[0011] Optionally, the distance of the second positive focus lens group meets the condition: 0.8<fU2 / f, wherein fU2 is the focal length of the second positive focus lens group, and f is the focal length of the lens.

[0012] Optionally, the second lens group also includes a first negative focal length lens group, which is located on the side of the second positive focus lens group close to the image side, and the first negative focal length lens group satisfies the condition: fU3 / f<-0.31, wherein fU3 is the focal length of the first negative focal length lens group, and f is the focal length of the lens.

[0013] Optionally, the first negative power lens group includes at least one negative lens made of flint glass.

[0014] Optionally, the second lens group further includes a second spherical meniscus positive lens close to the image side, the second spherical meniscus positive lens is convexly arranged toward the image side, and the second spherical meniscus positive lens satisfies the condition: nd>1.8, where nd is the refractive index of the second spherical meniscus positive lens.

[0015] Optionally, the first lens group satisfies the condition: FG1 / f>0.78, wherein FG1 is the focal length of the first lens group, and f is the focal length of the lens.

[0016] Optionally, the first lens group, the aperture and the second lens group are arranged to be able to move synchronously along the optical axis of the lens relative to the image plane corresponding to the lens.

[0017] The present application also provides a line scan detection device, which includes the above-mentioned lens.

[0018] The lens and line scan detection device provided by the present application have the following beneficial effects: compared with the prior art, the lens in the embodiment of the present application is provided with a first lens group with positive optical focal length, an aperture, and a second lens group with negative optical focal length in sequence from the object side to the image side, the first lens group includes a first positive focus lens group close to the aperture, the second lens group includes a second lens group on the side close to the aperture, the first positive focus lens group is arranged in front of the aperture to effectively correct coma and spherical aberration, the second positive focus lens group is arranged behind the aperture, and can be symmetrical with the first positive focus lens, which is beneficial to correcting off-axis aberrations, reducing distortion, and making the image quality uniform within the magnification range. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1A It is a 2D structural diagram of the first embodiment;

[0021] Figure 1B This is the FFT MTF diagram of Example 1 at the center magnification;

[0022] Figure 1C The normalized field of view vs. vertical axis chromatic aberration diagram at the center magnification and the edge magnification of Example 1;

[0023] Figure 1D The normalized field of view vs. distortion diagram at the center magnification and the edge magnification of Example 1;

[0024] Figure 2A It is a 2D structural diagram of the second embodiment;

[0025] Figure 2B This is the FFT MTF diagram of Example 2 at the center magnification;

[0026] Figure 2C The normalized field of view vs. vertical axis chromatic aberration diagram at the center magnification and the edge magnification of Example 2;

[0027] Figure 2D The normalized field of view vs. distortion diagram at the center magnification and edge magnification of Example 2;

[0028] Figure 3A It is a 2D structural diagram of Example 3;

[0029] Figure 3B This is the FFT MTF diagram of Example 3 at the center magnification;

[0030] Figure 3C The normalized field of view vs. vertical axis chromatic aberration diagram at the center magnification and the edge magnification of Example 3;

[0031] Figure 3D The normalized field of view vs. distortion diagram at the center magnification and edge magnification of Example 3.

[0032] Reference numerals: first lens group G1, second lens group G2, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, ninth lens L9, tenth lens L10, first positive power lens group U1, second positive power lens group U2, first negative power lens group U3. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0035] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] In addition, 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 this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] Traditional industrial imaging systems mostly use area array cameras, whose sensors are mostly rectangular. The entire sensor is composed of many (usually tens of thousands) photosensitive units arranged in a matrix. With the replacement of chips, while maintaining the advantage of large target surface, the resolution and system detection accuracy of area array cameras are getting higher and higher, such as the 151 million pixel industrial camera TTS151MCL. But in fact, the lateral resolution of area array cameras is still lower than that of mainstream line scan cameras. Therefore, in the field of high-precision detection of large-size targets, the use of line scan cameras is still a better choice. Line scan detection cameras are long strips, and the sensor consists of multiple photosensitive elements arranged in a row. The cost of use is lower than that of area array cameras, and the detection speed is fast, which can provide better quality detection services. With its technical and cost advantages. Line scan cameras are widely used in a variety of industrial inspections and service industries such as textile inspection, QR code and railway inspection. However, existing line scan lenses always have a compromise in performance indicators. Some do not support large target areas, some are limited by a narrow magnification range, some cannot meet the requirements of large apertures, etc. They have low tolerance for detection scenes, some have high distortion and uneven image quality, and are time-consuming and labor-intensive to use, and are inefficient.

[0038] See also Figure 1A , Figure 2A and Figure 3A , the lens provided by the embodiment of the present application is now described. The lens comprises a first lens group with positive focal power, an aperture, and a second lens group with negative focal power, which are arranged in sequence from the object side to the image side;

[0039] The first lens group includes a first positive focus lens group, the first positive focus lens group is located at a side of the first lens group close to the aperture, and the first positive focus lens group includes at least one positive lens;

[0040] The second lens group includes a second positive focus lens group, the second positive focus lens group is located at a side of the second lens group close to the aperture, and the second positive focus lens group includes at least one positive lens.

[0041] The first lens group with positive focal power is located at the front end of the lens from the object side to the image side, and is used to initially collect and focus the light from the object. The aperture is located after the first lens group and is used to limit the range of light entering the lens, thereby controlling the field of view of the image. The second lens group is located after the aperture and has negative focal power, which is used to further adjust the path and focal length of the light to achieve clear imaging.

[0042] The first lens group includes a first positive focus lens group, and the first positive focus lens group includes at least one positive lens. The first positive focus lens may specifically include one or more positive lenses, and may also include a negative lens. For example, Figure 1A and Figure 3A The first positive focus lens group shown includes a positive lens and a negative lens. Figure 2A The first positive focus lens group shown includes only one positive lens. The first positive focus lens group is located on the side of the first lens group close to the aperture, that is, the first positive focus lens is located before the aperture. The first positive focus lens group located before the aperture can converge light and compensate for the deviation of light when passing through different paths through its shape and refractive index distribution, thereby effectively correcting coma and spherical aberration.

[0043] The second lens group includes a second positive focus lens group, the second positive focus lens group includes at least one positive lens, and the second positive focus lens may specifically include one or more positive lenses, and may also include a negative lens. For example, Figure 1A The second positive focus lens group shown includes a positive lens and a negative lens. Figure 2A The second positive focus lens group shown includes two positive lenses and one negative lens. Figure 3A The second positive focus lens group shown in the figure only includes one positive lens. The second positive focus lens group is located on the side of the second lens group close to the aperture, that is, the second positive focus lens group is located behind the aperture. In this way, positive focal lens groups are arranged before and after the aperture. This symmetrical design is beneficial for correcting off-axis aberrations. By making the light trend symmetrical before and after the aperture, the uniformity of image quality within the magnification range can be ensured.

[0044] See also Figure 1A , Figure 2A and Figure 3A In some embodiments of the present application, the first lens group includes a first spherical meniscus positive lens close to the object side, the first spherical meniscus positive lens is convex toward the object side, and the focal length of the first lens satisfies the condition: f1 / f>0.42, wherein f1 is the focal length of the first spherical meniscus positive lens, and f is the focal length of the lens.

[0045] The first spherical meniscus positive lens is the lens of the first lens group close to the object side, and is also the first spherical lens of the entire lens. The spherical meniscus positive lens convex toward the object side helps to collect light with a large field of view on the object side. The first spherical meniscus positive lens can reduce the height of off-axis light and can effectively correct off-axis aberrations.

[0046] In this embodiment, by controlling the ratio of the focal length f1 of the first spherical meniscus positive lens to the focal length f of the lens to be greater than 0.42, the sensitivity of the lens during assembly can be reduced, which means that even if there is a slight assembly error, it will not have a significant impact on the imaging performance.

[0047] See also Figure 1A , Figure 2A and Figure 3AIn some embodiments of the present application, the first lens group includes at least one first cemented lens, the first cemented lens is located on the side of the first spherical meniscus positive lens close to the image side, the first cemented lens includes a positive lens and a negative lens, and the refractive index and Abbe number of the positive lens and the negative lens in the first cemented lens satisfy: vd p -vd n >20; and nd n -nd p >0.1;

[0048] Among them, vd p is the Abbe number of the positive lens of the first doublet, nd p is the refractive index of the positive lens of the first cemented lens, vd n is the Abbe number of the negative lens of the first doublet, nd n is the refractive index of the negative lens of the first cemented lens.

[0049] A cemented lens is a lens system in which multiple lens elements are bonded together by a cement. The lens of this embodiment includes one or more first cemented lenses, and the first cemented lens is located on the side of the first spherical meniscus positive lens close to the image side, that is, along the optical axis toward the image side, the first cemented lens is located behind the first spherical meniscus positive lens. The cemented lens has the function of reducing the total length of the lens system and improving the optical performance, such as reducing chromatic aberration and spherical aberration, and improving the imaging quality.

[0050] In this embodiment, the first cemented lens includes a positive lens and a negative lens, and the refractive index and Abbe number of the positive lens and the negative lens in the first cemented lens satisfy: vd p -vd n >20; and nd n -nd p >0.1. By controlling the relative size of the refractive index and the Abbe number in the first cemented lens, the chromatic aberration can be accurately corrected and the imaging quality can be improved. When the parameters do not meet the above conditions, the chromatic aberration of the system is in a state of under-correction or over-correction, and the lens is prone to overall color cast.

[0051] In some embodiments of the present application, the first positive focus lens group is located on a side of the first cemented lens close to the aperture, and the first positive focus lens group satisfies the condition: 0.4<fU1 / f<1.8, wherein fU1 is the focal length of the first positive focus lens group, and f is the focal length of the lens. The first positive focus lens group needs to be arranged in front of the aperture, and thus it is arranged on a side of the first cemented lens close to the aperture. The focal length of the first positive focus lens group has the function of correcting coma and spherical aberration. In this embodiment, the focal length of the first positive focus lens group needs to be controlled, wherein fU1 / f>0.4 is used to control the lower limit of the focal length of the first positive focus lens group, and a focal length greater than the lower limit helps to reduce aberrations, especially spherical aberration and coma, thereby improving imaging quality. fU1 / f<1.8 is used to control the upper limit of the focal length of the first positive focus lens group, and a focal length less than the upper limit helps to achieve a more compact lens design while maintaining sufficient imaging performance.

[0052] In some embodiments of the present application, the distance of the second positive focus lens group satisfies the condition: 0.8<fU2 / f, where fU2 is the focal length of the second positive focus lens group and f is the focal length of the lens. The second positive focus lens group is located after the aperture and can cooperate with the first positive focus lens group to make the light trend before and after the aperture symmetrical, which is beneficial to correct off-axis aberrations and make the image quality uniform within the magnification range. In this embodiment, the ratio of the focal length fU2 of the second positive focus lens group and the focal length f of the lens is controlled to be greater than 0.8, which ensures that the second positive focus lens group has sufficient positive focal length in the lens design, which helps to control the convergence of light and the imaging quality.

[0053] See also Figure 1A , Figure 2A and Figure 3A In some embodiments of the present application, the second lens group also includes a first negative focal length lens group, which is located on the side of the second positive focus lens group close to the image side, and the first negative focal length lens group satisfies the condition: fU3 / f<-0.31, wherein fU3 is the focal length of the first negative focal length lens group, and f is the focal length of the lens.

[0054] The first negative focal lens group is located on the side of the second positive focal lens group close to the image side, that is, located behind the first positive focal lens group. The focal length of the first negative focal lens group is a negative value. Due to the existence of the first negative focal lens group, the lens can cover a larger imaging area. The first negative focal lens group can include one or more negative lenses to share the optical focal length, so that the light height transition is smooth, which can better achieve a large imaging target surface and is beneficial to reduce assembly sensitivity. In this embodiment, the focal length fU3 of the first negative focal lens group and the focal length f of the lens are less than -0.31, which can ensure that the lens has sufficient negative focal length to achieve a large imaging target surface.

[0055] In some embodiments of the present application, the first negative power lens group includes at least one negative lens made of flint glass. The first negative power lens group may include one or more lenses, for example, Figure 1A and Figure 2A The first negative power lens group contains two lenses, and Figure 3A The first negative power lens group includes 3 lenses. Since the optical power of the first negative power lens group is negative, it includes at least one negative lens, or multiple negative lenses. At least one of these negative lenses is a negative lens made of flint glass. The high refractive index and high dispersion characteristics of flint glass are beneficial to correcting off-axis aberrations and chromatic aberrations, thereby improving imaging quality.

[0056] In addition, the optical power of the first cemented lens can also be negative, so that the light trends of the first negative power lens group and the optical power of the first cemented lens are symmetrically distributed, which is beneficial to correcting off-axis aberrations and making the image quality uniform within the magnification range.

[0057] See also Figure 1A , Figure 2A and Figure 3A In some embodiments of the present application, the second lens group further includes a second spherical meniscus positive lens close to the image side, the second spherical meniscus positive lens is convexly arranged toward the image side, and the second spherical meniscus positive lens satisfies the condition: nd>1.8, where nd is the refractive index of the second spherical meniscus positive lens.

[0058] The second spherical meniscus positive lens is the lens close to the image side in the second lens group. The lens is in the shape of a meniscus and is convex to the image side. This shape helps to control the deflection and focusing of light, so that the light is concentrated on the photosensitive element on the image side. The first negative focal length lens group is located before the second spherical meniscus positive lens. By matching the negative and positive lenses, a smaller main light angle is achieved, which is beneficial to improve the relative illumination.

[0059] In some embodiments of the present application, the first lens group satisfies the condition: FG1 / f>0.78, where FG1 is the focal length of the first lens group and f is the focal length of the lens. In this embodiment, by controlling the ratio of the focal length FG1 of the first lens group to the focal length f of the lens, the light of the first lens group can enter the aperture more smoothly, thereby reducing the aperture aberration.

[0060] In some embodiments of the present application, the first lens group, the aperture, and the second lens group are configured to move synchronously along the optical axis of the lens relative to the image plane corresponding to the lens. Figure 1AFor example, an image plane IMA is set on the right side of the second lens group. The image plane IMA is the image plane corresponding to the lens. The light passes through the first lens group, the aperture and the second lens group of the lens and converges on the image plane. The distance between the last lens of the lens and the image plane IMA is S1. The first lens group, the aperture and the second lens group can move synchronously along the optical axis of the lens. Therefore, the first lens group, the aperture and the second lens group can be moved synchronously, and the whole lens group can be focused, so as to achieve the change of magnification within a certain range.

[0061] Based on the above-mentioned lens, the present application also provides a line scanning detection device, which includes the lens in the above-mentioned embodiments. The lens in the embodiments of the present application is usually arranged in a line scanning detection device such as a line scanning camera for use, which can effectively correct off-axis aberrations and ensure uniform image quality. In addition, in combination with the above-mentioned embodiments, it can be seen that the lens in the embodiments of the present application has the advantages of supporting a large target surface, uniform image quality within the magnification range, large aperture, low distortion, and high relative illumination, and is particularly suitable for line scanning detection devices. It can improve the situation in which the lens performance indicators of the existing line scanning detection device always tend to lose sight of one thing while focusing on another.

[0062] The following are some embodiments of the present application.

[0063] Conditional data:

[0064] Embodiment 1 Embodiment 2 Embodiment 3 f1 / f>0.42 1.16 2.28 0.88 0.4<fU1 / f<1.8 1.13 0.44 0.81 0.8<fU2 / f 5.50 0.99 0.88 fU3 / f<-0.31 -0.60 -0.35 -0.34 FG1 / f>0.78 0.82 0.82 0.90

[0065] Embodiment 1:

[0066] The lens surface parameters of the lens are as follows:

[0067]

[0068]

[0069] Figure 1A It is a 2D structural diagram of the first embodiment;

[0070] The first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are arranged in sequence from the object side to the image side, wherein the first cemented lens is composed of the second lens L2 and the third lens L3; the first positive power lens group U1 is composed of the fourth lens L4 and the fifth lens L5.

[0071] The aperture stop is located between the first lens group G1 and the second lens group G2.

[0072] The second lens group G2 includes a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10 arranged in sequence from the object side to the image side, wherein the second positive focal power lens group U2 is composed of the sixth lens L6 and the seventh lens L7; the first negative focal power lens group U3 is composed of the eighth lens L8 and the ninth lens L9. The distance S1 between the tenth lens L10 and the image plane IMA is adjustable.

[0073] Figure 1B This is the FFT MTF diagram of Example 1 at the center magnification. The dotted line represents the sagittal direction, and the solid line represents the meridional direction. From the figure, the lens resolution reaches: 80lp / mm full field MTF is greater than 0.4, and the imaging is excellent;

[0074] Figure 1C The normalized field of view vs. vertical axis chromatic aberration diagram at the center magnification and the edge magnification of Example 1. It can be seen from the diagram that the chromatic aberration performance of the lens at different magnifications is good and relatively uniform;

[0075] Figure 1D The normalized field of view vs. distortion diagram at the center magnification and the edge magnification of Example 1. It can be seen from the diagram that the distortion of the lens at different magnifications is less than 0.1% and is relatively uniform.

[0076] Embodiment 2:

[0077] The lens surface parameters of the lens are as follows:

[0078] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 55.6 2.6 1.9 31.3 Sur2 Standard 75.6 4.3 Sur3 Standard -79.2 3.4 1.7 29.3 Sur4 Standard 34.4 10.0 1.6 64.0 Sur5 Standard 159.9 0.1 Sur6 Standard 50.0 8.3 2.0 28.3 Sur7 Standard -232.8 7.8 Stop Standard Infinity 2.1 Sur8 Standard 40.9 4.9 1.6 68.3 Sur9 Standard -50.6 1.5 1.8 25.5 Sur10 Standard 33.8 1.5 Sur11 Standard 66.8 10.1 2.0 28.3 Sur12 Standard -140.6 1.9 Sur13 Standard -56.0 10.2 1.6 38.0 Sur14 Standard 82.9 15.3 Sur15 Standard -20.9 2.9 1.5 70.4 Sur16 Standard -34.8 0.6 Sur17 Standard -239.4 9.2 1.6 68.3 Sur18 Standard -44.0 -

[0079] Figure 2A It is a 2D structural diagram of the second embodiment.

[0080] The first lens group G1 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 arranged in sequence from the object side to the image side, wherein the first cemented lens is composed of the second lens L2 and the third lens L3; the first positive focal power lens group U1 is composed of the fourth lens L4.

[0081] The aperture stop is located between the first lens group G1 and the second lens group G2.

[0082] The second lens group G2 includes a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10, which are arranged in sequence from the object side to the image side. The second positive focal power lens group U2 is composed of the fifth lens L5, the sixth lens L6, and the seventh lens L7; the first negative focal power lens group U3 is composed of the eighth lens L8 and the ninth lens L9. The distance S1 between the tenth lens L10 and the image plane IMA is adjustable.

[0083] Figure 2BThis is the FFT MTF diagram of Example 2 at the center magnification. The dotted line represents the sagittal direction, and the solid line represents the meridional direction. From the figure, the lens resolution reaches: 80lp / mm full field MTF is greater than 0.4, and the imaging is excellent;

[0084] Figure 2C The normalized field of view vs. vertical axis chromatic aberration diagram at the center magnification and the edge magnification of Example 2. It can be seen from the diagram that the chromatic aberration performance of the lens at different magnifications is good and relatively uniform;

[0085] Figure 2D The normalized field of view vs. distortion diagram at the center magnification and the edge magnification of Example 2. It can be seen from the diagram that the distortion of the lens at different magnifications is less than 0.1% and is relatively uniform.

[0086] Embodiment three:

[0087] The lens surface parameters of the lens are as follows:

[0088] Surface number Surface type R-Value thickness Refractive Index Abbe number Sur1 Standard 56.5 3.9 1.9 35.3 Sur2 Standard 199.5 1.9 Sur3 Standard -170.0 1.5 1.8 25.5 Sur4 Standard 25.2 8.6 1.6 62.0 Sur5 Standard 642.4 1.5 Sur6 Standard -103.9 10.0 1.6 42.8 Sur7 Standard 35.3 6.8 1.9 31.3 Sur8 Standard -110.3 4.1 Stop Standard Infinity 7.5 Sur9 Standard 94.2 5.0 2.0 25.4 Sur10 Standard -1247.4 0.7 Sur11 Standard -145.5 6.9 1.7 30.0 Sur12 Standard 22.9 10.0 1.6 62.0 Sur13 Standard 84.3 19.1 Sur14 Standard -23.2 1.5 1.8 32.2 Sur15 Standard -37.4 2.9 Sur16 Standard -157.9 6.7 1.8 52.3 Sur17 Standard -51.4 -

[0089] Figure 3A It is a 2D structural diagram of Example 3;

[0090] The first lens group G1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are arranged in sequence from the object side to the image side, wherein the first cemented lens is composed of the second lens L2 and the third lens L3; the first positive power lens group U1 is composed of the fourth lens L4 and the fifth lens L5.

[0091] The aperture stop is located between the first lens group G1 and the second lens group G2.

[0092] The second lens group G2 includes a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10, which are arranged in sequence from the object side to the image side. The second positive focal power lens group U2 is composed of the sixth lens L6; the first negative focal power lens group U3 is composed of the seventh lens L7, the eighth lens L8, and the ninth lens L9. The distance between the tenth lens L10 and the image plane IMA is adjustable.

[0093] Figure 3B This is the FFT MTF diagram of Example 3 at the center magnification. The dotted line represents the sagittal direction, and the solid line represents the meridional direction. From the figure, the lens resolution reaches: 80lp / mm full field MTF is greater than 0.4, and the imaging is excellent;

[0094] Figure 3C The normalized field of view vs. vertical axis chromatic aberration diagram at the center magnification and the edge magnification of Example 3. It can be seen from the diagram that the chromatic aberration performance of the lens at different magnifications is good and relatively uniform;

[0095] Figure 3D The normalized field of view vs. distortion diagram at the center magnification and edge magnification of Example 3. From the diagram, it can be seen that the distortion of the lens at different magnifications is less than 0.1% and is relatively uniform;

[0096] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A lens, characterized in that: The lens comprises a first lens group with positive focal power, an aperture, and a second lens group with negative focal power, which are arranged in sequence from the object side to the image side; The first lens group includes a first positive focus lens group, the first positive focus lens group is located on a side of the first lens group close to the aperture stop, and the first positive focus lens group includes at least one positive lens; The second lens group includes a second positive focus lens group, the second positive focus lens group is located at a side of the second lens group close to the aperture stop, and the second positive focus lens group includes at least one positive lens.

2. The lens according to claim 1, characterized in that: The first lens group includes a first spherical meniscus positive lens close to the object side, the first spherical meniscus positive lens is convex toward the object side, and the focal length of the first spherical meniscus positive lens satisfies the condition: f1 / f>0.42, wherein f1 is the focal length of the first spherical meniscus positive lens, and f is the focal length of the lens.

3. The lens according to claim 2, characterized in that: The first lens group includes at least one first cemented lens, the first cemented lens is located on the side of the first spherical meniscus positive lens close to the image side, the first cemented lens includes a positive lens and a negative lens, and the refractive index and Abbe number of the positive lens and the negative lens in the first cemented lens satisfy: vd p -vd n >20; and nd n -nd p >0.1; Among them, vd p is the Abbe number of the positive lens of the first cemented lens, nd p is the refractive index of the positive lens of the first cemented lens, vd n is the Abbe number of the negative lens of the first cemented lens, nd n is the refractive index of the negative lens of the first cemented lens.

4. The lens according to claim 3, characterized in that: The first positive focus lens group is located on a side of the first cemented lens close to the aperture, and the first positive focus lens group satisfies the condition: 0.4<fU1 / f<1.8, wherein fU1 is the focal length of the first positive focus lens group, and f is the focal length of the lens.

5. The lens according to claim 1, wherein: The distance of the second positive focus lens group meets the condition: 0.8<fU2 / f, where fU2 is the focal length of the second positive focus lens group and f is the focal length of the lens.

6. The lens according to claim 5, characterized in that: The second lens group also includes a first negative focal length lens group, which is located on a side of the second positive focus lens group close to the image side, and the first negative focal length lens group satisfies the condition: fU3 / f<-0.31, wherein fU3 is the focal length of the first negative focal length lens group, and f is the focal length of the lens.

7. The lens according to claim 6, characterized in that: The first negative power lens group includes at least one negative lens made of flint glass.

8. The lens according to claim 6, wherein: The second lens group further includes a second spherical meniscus positive lens close to the image side. The second spherical meniscus positive lens is convexly arranged toward the image side. The second spherical meniscus positive lens satisfies the condition: nd>1.8, where nd is the refractive index of the second spherical meniscus positive lens.

9. The lens according to any one of claims 1 to 8, characterized in that: The first lens group satisfies the condition: FG1 / f>0.78, wherein FG1 is the focal length of the first lens group, and f is the focal length of the lens.

10. The lens according to any one of claims 1 to 8, characterized in that: The first lens group, the aperture and the second lens group are arranged to be able to move synchronously along the optical axis of the lens relative to the image plane corresponding to the lens.

11. A line scan detection device, characterized in that: The line scan detection device comprises the lens described in any one of claims 1-10.

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