Industrial lens and camera module
By rationally designing the lens group power and refractive index temperature coefficient of industrial lenses, the problem of out-of-focus in industrial lenses under temperature changes is solved, and high-quality imaging in visible light and near-infrared bands is achieved.
Patent Information
- Application Number
- CN202422360978.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2034-09-26
AI Technical Summary
Existing industrial lenses have clear imaging in the visible and near-infrared band ranges, but cannot adapt to the temperature changes in the actual environment, resulting in out-of-focus problems.
An industrial lens is designed to maintain confocality in the range of 10°C to 40°C by reasonably allocating the power and refractive index temperature coefficient of the lens group, including at least two lenses with positive power, whose refractive index temperature coefficient satisfies the relationship between (dndT) Lx≥10×10-6/°C.
Confocal in the temperature range of 10°C to 40°C is achieved, ensuring high-quality imaging in the visible light and near-infrared band, with an image surface offset of less than 0.15mm and excellent imaging quality.
Smart Images
Figure CN223166965U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical imaging technology, and particularly to an industrial lens and a camera module. Background Art
[0002] Machine vision inspection technology is widely applied to various links of manufacturing industry. As the core imaging component of the machine vision system, the industrial lens occupies an indispensable position in the machine vision industry chain. The quality of the industrial lens is directly related to the performance of the entire vision system. Imaging is the basis for the operation of the machine vision system. Whether it is information acquisition, processing or analysis, it is inseparable from high-quality image data captured by the industrial lens. Therefore, the performance of the industrial lens directly affects the effective processing and accurate judgment of image information by the machine vision system.
[0003] The industrial lenses in the related art achieve clear imaging in the visible light and near-infrared wavelength ranges. However, the fluctuations of the actual environment are ignored. For example, the change of the on-site working temperature causes defocusing and other phenomena of the industrial lens. Summary of the Utility Model
[0004] The embodiments of this application provide an industrial lens and a camera module that can achieve confocal imaging in visible light and near-infrared light, and will not defocus within the range of 10°C - 40°C, and have excellent imaging performance.
[0005] To achieve the above object, the embodiments of this application adopt the following technical solutions:
[0006] In a first aspect, the embodiments of this application provide an industrial lens, whose working frequency band is 400nm - 1000nm. The industrial lens includes a first lens group and a second lens group arranged from the object side to the image side. The first lens group has a positive optical power, and the second lens group has a positive optical power; the industrial lens includes at least 2 lenses with positive optical power, and the refractive index temperature coefficient (dn / dT) of the lens with positive optical power Lx satisfies the relation at 10°C - 40°C: (dn / dT) Lx ≥10×10 -6 / °C; where n is the refractive index of the x-th lens Lx arranged from the object side to the image side in the industrial lens, and T is the temperature.
[0007] By reasonably distributing the optical power of each lens group of the industrial lens, the aberration can be well corrected, thereby improving the imaging quality; by reasonably designing each optical parameter in the industrial lens, and when the refractive index temperature coefficient of the lens with optical power in the industrial lens satisfies the above relationship, the industrial lens can be confocal in the working wavelength range of 400nm to 1000nm, that is, in the visible light and near-infrared wavelength range, and at the same time, the image plane shift meets the requirements in the range of 10°C to 40°C, so as to achieve confocal in the temperature range of 10°C to 40°C.
[0008] In some embodiments, the focal length f1 of the first lens group and the focal length f of the industrial lens satisfy the relationship: 0.5 ≤ f / f1 ≤ 0.75.
[0009] In some embodiments, the focal length f2 of the second lens group and the focal length f of the industrial lens satisfy the relationship: 0.7 ≤ f / f2 ≤ 1.
[0010] In some embodiments, the absolute value |β| of the lateral magnification of the industrial lens satisfies the relationship: 0.3 ≤ |β| ≤ 1.
[0011] In some embodiments, the industrial lens includes at least 2 lenses with positive optical power, and the refractive index nd of the lens with positive optical power Lx and the Abbe number vd Lx satisfy the relationship: 1.4 ≤ nd Lx ≤ 1.6; 65 ≤ vd Lx ≤ 95.5.
[0012] In some embodiments, the first lens group includes 2 lenses with positive optical power and 1 lens with negative optical power, and the second lens group includes 2 lenses with positive optical power and 3 lenses with negative optical power.
[0013] In some embodiments, the first lens group includes a first lens, a second lens, and a third lens arranged from the object side to the image side, the first lens and the second lens have positive optical power, and the third lens has negative optical power; the second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged from the object side to the image side, the sixth lens and the eighth lens have positive optical power, and the fourth lens, the fifth lens, and the seventh lens have negative optical power.
[0014] In some embodiments, the second lens and the third lens form a cemented lens; the fifth lens and the sixth lens form a cemented lens, and / or, the seventh lens and the eighth lens form a cemented lens.
[0015] In some embodiments, the industrial lens further includes a diaphragm, and the diaphragm is located between the first lens and the second lens.
[0016] In a second aspect, an embodiment of the present application provides a camera module including the industrial lens described in the first aspect.
[0017] The structure and the achieved technical effects of the camera module in the embodiment of the present application are the same as those of the industrial lens in the first aspect, and will not be elaborated here. Description of the Drawings
[0018] Figure 1 Schematic diagram of the structure of the industrial lens provided in Embodiment 1 of the present application;
[0019] Figure 2 MTF diagram of the industrial lens provided in Embodiment 1 of the present application at room temperature of 25°C;
[0020] Figure 3 MTF diagram of the industrial lens provided in Embodiment 1 of the present application at low temperature of 10°C;
[0021] Figure 4 MTF diagram of the industrial lens provided in Embodiment 1 of the present application at high temperature of 40°C;
[0022] Figure 5 MTF diagram of the industrial lens provided in Embodiment 1 of the present application in the confocal state of near-infrared and visible light;
[0023] Figure 6 Lateral chromatic aberration diagram of the industrial lens provided in Embodiment 1 of the present application;
[0024] Figure 7 Schematic diagram of the structure of the industrial lens provided in Embodiment 2 of the present application;
[0025] Figure 8 MTF diagram of the industrial lens provided in Embodiment 2 of the present application at room temperature of 25°C;
[0026] Figure 9 MTF diagram of the industrial lens provided in Embodiment 2 of the present application at low temperature of 10°C;
[0027] Figure 10 MTF diagram of the industrial lens provided in Embodiment 2 of the present application at high temperature of 40°C;
[0028] Figure 11 MTF diagram of the industrial lens provided in Embodiment 2 of the present application in the confocal state of near-infrared and visible light;
[0029] Figure 12 Lateral chromatic aberration diagram of the industrial lens provided in Embodiment 2 of the present application;
[0030] Figure 13 Schematic diagram of the structure of the industrial lens provided in Embodiment 3 of the present application;
[0031] Figure 14 MTF diagram of the industrial lens provided in Embodiment 3 of the present application at room temperature of 25°C;
[0032] Figure 15 MTF diagram of the industrial lens provided in Embodiment 3 of the present application in the confocal state of near-infrared and visible light;
[0033] Figure 16 MTF diagram of the industrial lens provided in Embodiment 3 of the present application at low temperature of 10°C;
[0034] Figure 17 MTF diagram of the industrial lens provided in Embodiment 3 of the present application at high temperature of 40°C;
[0035] Figure 18 Lateral chromatic aberration diagram of the industrial lens provided in Embodiment 3 of the present application;
[0036] Figure 19 Schematic diagram of the structure of the industrial lens provided in Embodiment 4 of the present application;
[0037] Figure 20 MTF diagram of the industrial lens provided in Embodiment 4 of the present application at room temperature of 25°C;
[0038] Figure 21 MTF diagram of the industrial lens provided in Embodiment 4 of the present application at low temperature of 10°C;
[0039] Figure 22 MTF diagram of the industrial lens provided in Embodiment 4 of the present application at high temperature of 40°C;
[0040] Figure 23 MTF diagram of the industrial lens provided in Embodiment 4 of the present application in the confocal state of near-infrared and visible light;
[0041] Figure 24 Lateral chromatic aberration diagram of the industrial lens provided in Embodiment 4 of the present application.
[0042] Among them, each reference numeral in the figure:
[0043] The first lens group G1; the second lens group G2; the first lens L1; the second lens L2; the third lens L3; the fourth lens L4; the fifth lens L5; the sixth lens L6; the seventh lens L7; the eighth lens L8; the aperture STOP; the imaging surface IMAGE. Detailed implementation manners
[0044] For the convenience of understanding, the following first explains and describes the English abbreviations and related technical terms involved in the embodiments of the present application.
[0045] Focal power, which is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, characterizes the ability of an optical lens to deflect light rays.
[0046] A lens or lens group with positive focal power has a positive focal length and has the effect of converging light rays.
[0047] A lens or lens group with negative focal power has a negative focal length and has the effect of diverging light rays.
[0048] Focal length, also known as the focal length, is a measure of the aggregation or divergence of light in an optical lens. It refers to the perpendicular distance from the optical center of the 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 in the optical center of the lens brings about a change in the focal length of the lens.
[0049] The effective focal length (EFL) of a lens is the distance from the center of the lens to the focus.
[0050] The combined focal length is the combination of the focal lengths of the individual lenses in a lens group.
[0051] Object side: Taking the lens as the boundary, the side where the object to be photographed is located is the object side, and the surface of the lens close to the object side is called the object side surface.
[0052] Image side: Taking the lens as the boundary, the side where the image of the object to be photographed is located is the image side, and the surface of the lens close to the image side is called the image side surface.
[0053] Aperture diaphragm is a device used to control the amount of light passing through the lens and entering the photosensitive surface inside the camera body. It is usually inside the lens.
[0054] The imaging plane is located on the image side of all the lenses in the optical lens, and is the plane where the light forms an image after passing through each lens in the optical lens in sequence.
[0055] The optical axis is an axis perpendicular to the center of the lens. The optical axis of an optical lens is the axis passing through the centers of all the lenses of the lens.
[0056] The focus is the convergence point of parallel light rays refracted by a lens or lens group.
[0057] The Abbe number, i.e., the dispersion coefficient, is the ratio of the difference in refractive indices of an optical material at different wavelengths, representing the degree of material dispersion.
[0058] Aberration: An optical lens has the properties of an ideal optical system on the optical axis. The light rays emitted from a point on an object and close to the axis intersect at a point on the image plane (i.e., the axial image point). However, the light rays actually passing through different apertures of the lens are difficult to perfectly intersect at a point, but deviate from the position of the paraxial image point by a certain amount. These differences are collectively referred to as aberrations.
[0059] Distortion, also known as aberration, is the degree of distortion of the image formed by an optical lens with respect to the object itself. Distortion is due to the influence of spherical aberration of the diaphragm. The height of the chief ray passing through the optical lens at different fields of view does not equal the ideal image height when intersecting with the Gaussian image plane, and the difference between the two is the distortion.
[0060] The lateral magnification (β) represents the ratio of the image height to the object height of conjugate planes. In an optical system, the lateral magnification describes the proportional relationship between the height of the image and the height of the object in a plane perpendicular to the optical axis.
[0061] Relative Illumination (RI), relative illumination is the ratio of the central illumination to the peripheral illumination. Illumination is defined as the degree of brightness presented by an object or a surface being illuminated by a light source.
[0062] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.
[0063] In the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "plural" is two or more.
[0064] As Figure 1 shown, in some embodiments, the camera module includes an industrial lens and a photosensitive element (IMAGE in Figure 1), and the photosensitive element is located on the image side of the industrial lens ( Figure 1 the right side in
[0065] The working principle of the camera module is as follows: The light reflected by the object to be photographed passes through the industrial lens to generate an optical image, which is projected onto the photosensitive surface of the photosensitive element. The photosensitive element converts the optical image into an electrical signal, i.e., an analog image signal, and transmits it to the processor.
[0066] Among them, the photosensitive element (also known as the image sensor, located at the imaging surface IMA on the far right) is a semiconductor chip with hundreds of thousands to millions of photodiodes on its surface. When irradiated by light, it generates electric charges. The photosensitive element can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor device (CMOS). CCD is made of a high-sensitivity semiconductor material and can convert light into electric charges. The charge-coupled device consists of many photosensitive units, usually in units of millions of pixels. When the surface of the photosensitive element is irradiated by light, each photosensitive unit reflects the electric charge on the component, and the signals generated by all the photosensitive units are added together to form a complete picture. Figure 1 Among them, the industrial lens mainly uses the refraction principle of the lens for imaging, that is, the light of the scene passes through the industrial lens to form a clear image on the focal plane, and the image of the scene is recorded by the photosensitive element located on the focal plane.
[0067] It should be noted that the optical lens can be, but is not limited to, a line scan lens, and its working wavelength range is 400nm - 1000nm, that is, the visible light and near-infrared wavelength ranges.
[0068] As shown in the figure, the industrial lens includes a first lens group G1 and a second lens group G2 arranged from the object side to the image side. The first lens group G1 has a positive focal power, and the second lens group G2 has a positive focal power; the industrial lens includes at least 2 lenses with positive focal power, and the refractive index temperature coefficient (dn / dT) of the lens with positive focal power
[0069] such as Figure 1 satisfies the relationship: (dn / dT) Lx ≥ 10 × 10 Lx / ℃ at 10℃ - 40℃. -6 / ℃.
[0070] The above (dn / dT) Lx is the derivative of the refractive index of the x-th lens Lx arranged from the object side to the image side in the industrial lens with respect to the temperature T.
[0071] By reasonably distributing the optical power of each lens group of the industrial lens, the aberration can be well corrected, thereby improving the imaging quality; by reasonably designing each optical parameter in the industrial lens, and when the refractive index temperature coefficient of the lens with optical power in the industrial lens satisfies the above relationship, the industrial lens can be confocal in the working wavelength range of 400nm to 1000nm, that is, the visible light and near-infrared wavelength range, and at the same time, within the range of 10°C to 40°C, the image plane shift meets the requirements, so as to achieve confocal within the temperature range of 10°C to 40°C.
[0072] It should be noted that the refractive index temperature coefficient of the lens with positive optical power is limited. That is to say, in the process of designing the industrial lens, it is necessary to meet the requirement that at least two lenses simultaneously have positive optical power and the refractive index temperature coefficient of the material of the lens satisfies the above relationship. However, the refractive index temperature coefficients of at least two lenses with positive optical power can be the same or different.
[0073] Figure 1 The structural diagram of the industrial lens of Embodiment 1 is shown. The industrial lens includes a first lens group G1, a stop STOP, and a second lens group G2 arranged from the object side to the image side. The first lens group G1 has positive optical power, and the second lens group G2 has positive optical power;
[0074] Among them: The first lens group G1 includes a first lens L1, a second lens L2, and a third lens L3 arranged from the object side to the image side; the second lens L2 and the third lens L3 are glued together to form a glued lens;
[0075] Among them: The second lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 arranged from the object side to the image side; the fifth lens L5 and the sixth lens L6 are glued together to form a first glued lens, and the seventh lens L7 and the eighth lens L8 are glued together to form a first glued lens.
[0076] Tables 1a to 1c respectively give the specific parameter values of each lens of the industrial lens in an optional embodiment of Embodiment 1 of the present application.
[0077] Table 1a
[0078] Surface Number Surface Type R Value Thickness Refractive Index Abbe Number Sur1 Standard 67.87 9.06 1.83 37.2 Sur2 Standard 287.68 1.32 Sur3 Standard 37.28 5.74 1.50 81.6 Sur4 Standard -491.25 7.09 1.65 39.5 Sur5 Standard 28.77 8.27 STOP Standard Infinity 5.71 Sur7 Standard -74.09 2.41 1.95 17.9 Sur8 Standard -52.86 3.98 Sur9 Standard -42.63 6.22 1.77 29.7 Sur10 Standard 73.31 7.03 1.59 68.3 Sur11 Standard -41.04 4.53 Sur12 Standard -32.54 1.75 1.55 45.8 Sur13 Standard 197.2 6.93 1.83 37.2 Sur14 Standard -44.58 137.48 Image Standard Infinity -
[0079] It should be noted that in Table 1a, the "surface serial number" is the serial number of each surface arranged in sequence from the object side to the image side. The radius R value is for the lens corresponding to the surface number, that is, the curvature radius of the object side or image side of the lens corresponding to each surface serial number at the optical axis. The "infinity" in the "curvature radius" parameter sequence of the lens means that the object side or image side of the lens is a plane; the first value in the "thickness / spacing" parameter sequence for each lens is the thickness of the lens on the optical axis, and the second value is the distance on the optical axis from the image side of this lens to the object side of the subsequent lens.
[0080] In the industrial lens of Embodiment 1, the positive and negative situations of the optical power of each lens are shown in Table 1b.
[0081] Table 1b
[0082]
[0083] It should be noted that the "+" and "-" in Table 1b represent the positive and negative situations of the optical power of each lens in the industrial lens of Embodiment 1. Among them, "+" represents that the lens has positive optical power; "-" represents that the lens has negative optical power.
[0084] In the industrial lens of Embodiment 1, the convex and concave situations of the object side or image side of each lens at the optical axis are shown in Table 1c.
[0085] Table 1c
[0086]
[0087] It should be noted that the "++", "+-", "-+", "--" in Table 1c represent the convex and concave situations of the object side or image side of each lens at the optical axis. Among them, "++" represents that both the object side and the image side of the lens convex towards the object side at the optical axis; "+-" represents that the object side of the lens convex towards the object side at the optical axis and the image side convex towards the image side at the optical axis, that is, a biconvex structure; "-+" represents that the object side of the lens concave towards the object side at the optical axis and the image side convex towards the image side at the optical axis, that is, a biconcave structure; "--" represents that both the object side and the image side of the lens concave towards the object side at the optical axis. Of course, in addition to the above convex and concave situations, each lens in the industrial lens can also include any one or more of "∞-", "+∞", "∞+", "-∞". Among them, "∞-" represents that the object side of the lens is a plane at the optical axis and the image side concave towards the object side at the optical axis; "+∞" represents that the object side of the lens convex towards the object side at the optical axis and the image side is a plane at the optical axis; "∞+" represents that the object side of the lens is a plane at the optical axis and the image side convex towards the image side at the optical axis; "-∞" represents that the object side of the lens concave towards the object side at the optical axis and the image side is a plane at the optical axis. No specific limitations are made here.
[0088] As can be seen from Table 1a and Table 1b, the second lens L2 in this industrial lens has a positive focal power, and the refractive index and Abbe number of the second lens L2: nd L2 is 1.50, vd L2 is 81.6; the refractive index and Abbe number of the sixth lens L6: nd L6 is 1.59, vd L6 is 68.3.
[0089] The working wavelength range of the industrial lens in this embodiment is 400 - 1000 nm, i.e., the visible light and near-infrared wavelength range; the total optical length TTL is 207.52 mm, the focal length f is 133.35 mm, and the absolute value of the lateral magnification |β| is 0.3 times.
[0090] In this embodiment, the first lens L1 of the industrial lens has a positive focal power, and the refractive index temperature coefficient of the first lens L1 at 10 °C to 40 °C: (dndT) L1 = 10.3×10 -6 / °C;
[0091] The eighth lens L8 of the industrial lens has a positive focal power, and the refractive index temperature coefficient of the eighth lens L8 at 10 °C to 40 °C: (dndT) L8 = 10.3×10 -6 / °C.
[0092] Combined with Figure 1 the structural schematic diagram of the industrial lens in Embodiment 1, and the main parameters of the industrial lens in Embodiment 1 given in Table 1a to Table 1c and the concavity and convexity of each lens at the optical axis. The MTF graph and the lateral chromatic aberration graph of the industrial lens in Embodiment 1 in the working wavelength range of 400 - 1000 nm and the temperature range of 10 °C to 40 °C are obtained through simulation, as shown in Figures 2 to 6 .
[0093] Among them: The MTF graphs are all curves reflecting the reduction of the contrast (reduction degree) of the industrial lens. Among them, the MTF graph is a Modulation transfer function graph, the dashed line represents the sagittal direction, and the solid line represents the meridional direction. The ordinate of the MTF graph reflects the quality of the contrast, or rather, the quality of the reduction degree. The higher the ordinate value of the MTF graph, the better the reduction degree and the higher the resolution of the industrial lens.
[0094] The lateral color aberration diagram usually shows the deviation of light rays of different wavelengths on the image plane. The abscissa in the diagram usually represents the position of the light ray on the image plane, and the ordinate represents the distance of the light ray of different wavelengths from the chief ray. The lateral color aberration is manifested as different dispersion spots formed by light rays of different wavelengths on the image plane, resulting in a colored edge of the image. The shape and slope of the curve in the diagram can help judge the severity of the lateral color aberration.
[0095] The above descriptions of the MTF diagram and the lateral color aberration diagram are the same as those in other embodiments, and will not be repeated hereinafter.
[0096] Combined with Figures 2 to 4 It can be seen that in the industrial lens of this embodiment, within the temperature range of 10°C to 40°C, the image plane offset is small, achieving confocal imaging.
[0097] From Figure 5 It can be seen that in the industrial lens of this embodiment, within the working wavelength range of 400 - 1000nm, the image plane offset is small, achieving confocal imaging.
[0098] From Figure 6 It can be seen that the maximum target surface of the industrial lens in this embodiment can reach 82mm, and the curve slope is small, indicating excellent imaging quality of the industrial lens.
[0099] Combined with Figures 1 to 6 It can be seen that the maximum target surface of the industrial lens in this embodiment can reach 82mm. Within the working wavelength range of 400 - 1000nm and the temperature range of 10°C to 40°C, the image plane offset is less than 0.15mm, that is, confocal imaging is achieved within the visible light and near-infrared wavelength range, and the imaging quality is excellent.
[0100] Figure 7 The structural diagram of the industrial lens of Embodiment 2 is shown. The main differences between the industrial lens in Embodiment 2 and the industrial lens in the above First Embodiment are the number of lenses in the industrial lens and the position of the first cemented lens, the parameters and conditions satisfied by each lens in the industrial lens, and the concavity and convexity of the object side or image side of each lens at the optical axis.
[0101] Tables 2a to 2c respectively give the specific parameter values of each lens of the industrial lens in an optional embodiment of Embodiment 2 of this application.
[0102] Table 2a
[0103] Surface Number Surface Type R Value Thickness Refractive Index Abbe Number Sur1 Standard 67.87 9.06 1.83 37.2 Sur2 Standard 287.68 2.36 Sur3 Standard 40.24 5.7 1.50 81.6 Sur4 Standard -227.48 7.28 1.65 39.5 Sur5 Standard 30.73 6.96 STOP Standard Infinity 5.74 Sur7 Standard -74.09 2.41 1.95 17.9 Sur8 Standard -52.86 4.96 Sur9 Standard -42.52 2.55 1.77 29.7 Sur10 Standard 69.82 10.01 1.59 68.3 Sur11 Standard -41.64 3.04 Sur12 Standard -32.54 1.75 1.55 45.8 Sur13 Standard 197.2 6.93 1.83 37.2 Sur14 Standard -44.58 167.83 Image Standard Infinity -
[0104] In the industrial lens of Embodiment 2, the positive and negative conditions of the optical power of each lens are shown in Table 2b.
[0105] Table 2b
[0106]
[0107] In the industrial lens of the second embodiment, the concavity and convexity of the object side or the image side of each lens on the optical axis are shown in Table 2c.
[0108] Table 2c
[0109]
[0110] As can be seen from Table 2a and Table 2b, the second lens L2 in this industrial lens has a positive optical power, and the refractive index and Abbe number of the second lens L2: nd L2 is 1.50, vd L2 is 81.6; the sixth lens L6 has a positive optical power, and the refractive index and Abbe number of the sixth lens L6: nd L6 is 1.59, vd L6 is 68.3.
[0111] The working wavelength range of the industrial lens in this embodiment is 400 - 1000 nm, i.e., the visible light and near-infrared wavelength range; the overall optical length TTL is 236.58 mm, the focal length f is 138.09 mm, and the absolute value of the lateral magnification |β| is 0.5 times.
[0112] In this embodiment, the first lens L1 of the industrial lens has a positive optical power, and the refractive index temperature coefficient of the first lens L1 at 10 °C to 40 °C: (dndT) L1 = 10.3×10 -6 / °C;
[0113] The eighth lens L8 of the industrial lens has a positive optical power, and the refractive index temperature coefficient of the eighth lens L8 at 10 °C to 40 °C: (dndT) L8 = 10.3×10 -6 / °C.
[0114] Combined with Figure 7 the structural schematic diagram of the industrial lens in the second embodiment, and the main parameters of the industrial lens in the second embodiment given in Tables 2a to 2c and the concavity and convexity of each lens on the optical axis. The MTF graph and the lateral chromatic aberration graph of the industrial lens in the second embodiment in the working wavelength range of 400 - 1000 nm and the temperature range of 10 °C to 40 °C are obtained through simulation, as Figures 8 to 12 shown.
[0115] Combined with Figures 8 to 10 it can be seen that in the temperature range of 10 °C to 40 °C, the image plane offset of the industrial lens in this embodiment is small, and confocal is achieved.
[0116] From Figure 11It can be seen that in the industrial lens of this embodiment, within the working wavelength range of 400 - 1000 nm, the image plane offset is small, achieving confocal imaging.
[0117] From Figure 12 It can be seen that the maximum target surface of the industrial lens in this embodiment can reach 82 mm, and the curve slope is small, indicating excellent imaging quality of the industrial lens.
[0118] Combined with Figures 7 to 12 It can be seen that the target surface of the industrial lens in this embodiment can reach 82 mm. Within the working wavelength range of 400 - 1000 nm and the temperature range of 10℃ - 40℃, the image plane offset is less than 0.15 mm, that is, confocal imaging is achieved within the visible light and near-infrared wavelength ranges, and the imaging quality is excellent.
[0119] Figure 13 The structural diagram of the industrial lens of Embodiment 3 is shown. The main differences between the industrial lens of Embodiment 3 and the industrial lens of the above First Embodiment lie in the number of lenses in the industrial lens and the position of the first cemented lens, the parameters and satisfied conditions of each lens in the industrial lens, and the concavity and convexity of the object side or image side of each lens at the optical axis.
[0120] Tables 3a to 3c respectively give the specific parameter values of each lens of the industrial lens of an optional embodiment in Embodiment 3 of this application.
[0121] Table 3a
[0122] Surface Number Surface Type R Value Thickness Refractive Index Abbe Number Sur1 Standard 67.87 9.06 1.83 37.2 Sur2 Standard 287.68 6.15 Sur3 Standard 37.22 5.06 1.50 81.6 Sur4 Standard -279.24 5.08 1.65 39.5 Sur5 Standard 28.9 9.22 STOP Standard Infinity 5.74 Sur7 Standard -74.09 2.41 1.95 17.9 Sur8 Standard -52.86 3.97 Sur9 Standard -36.79 1.09 1.77 29.7 Sur10 Standard 76.48 6.39 1.59 68.3 Sur11 Standard -31.2 1.78 Sur12 Standard -25.49 3.52 1.55 45.8 Sur13 Standard 267.06 7.07 1.83 37.2 Sur14 Standard -37.92 172.667 Image Standard Infinity -
[0123] For the industrial lens of Embodiment 3, the positive and negative situations of the optical power of each lens are shown in Table 3b.
[0124] Table 3b
[0125]
[0126] For the industrial lens of Embodiment 3, the concavity and convexity of the object side or image side of each lens at the optical axis are shown in Table 3c.
[0127] Table 3c
[0128]
[0129] As can be seen from Table 3a and Table 3b, the second lens L2 in this industrial lens has positive optical power, and the refractive index and Abbe number of the second lens L2 are: ndL2 is 1.50, vdL2 is 81.6; the sixth lens L6 has positive optical power, and the refractive index and Abbe number of the sixth lens L6 are: ndL6 is 1.59, vdL6 is 68.3.
[0130] In this embodiment, the working wavelength range of the industrial lens is 400 - 1000nm, i.e., the visible light and near-infrared wavelength range; the total optical length TTL is 239.21mm, the focal length f is 129.11mm, and the absolute value of the lateral magnification |β| is 0.6x.
[0131] In this embodiment, the first lens L1 of the industrial lens has a positive optical power. The refractive index temperature coefficient of the first lens L1 at 10℃ - 40℃: (dn / dT) L1 = 10.3×10 -6 / ℃;
[0132] The eighth lens L8 of the industrial lens has a positive optical power. The refractive index temperature coefficient of the eighth lens L8 at 10℃ - 40℃: (dn / dT) L8 = 10.3×10 -6 / ℃.
[0133] Combined with Figure 13 the structural schematic diagram of the industrial lens in Embodiment 3, and the main parameters of the industrial lens in Embodiment 3 given in Tables 3a to 3c and the concavity and convexity of each lens on the optical axis. The MTF graph and lateral chromatic aberration graph of the industrial lens in Embodiment 3 in the working wavelength range of 400 - 1000nm and the temperature range of 10℃ - 40℃ are obtained through simulation, as Figures 14 to 15 shown.
[0134] Combined with Figure 14 Figure 16 It can be seen that the image plane offset of the industrial lens in this embodiment is small in the temperature range of 10℃ - 40℃, achieving confocal.
[0135] From Figure 17 it can be seen that the image plane offset of the industrial lens in this embodiment is small in the working wavelength range of 400 - 1000nm, achieving confocal.
[0136] From Figure 18 it can be seen that the maximum target surface of the industrial lens in this embodiment can reach 82mm, and the curve slope is small, indicating excellent imaging quality of the industrial lens.
[0137] Combined with Figures 13 to 18 it can be seen that the target surface of the industrial lens in this embodiment can reach 82mm. In the working wavelength range of 400 - 1000nm and the temperature range of 10℃ - 40℃, the image plane offset is less than 0.15mm, that is, confocal is achieved in the visible light and near-infrared wavelength range, and the imaging quality is excellent.
[0138] Figure 19Shows the structural diagram of the industrial lens of the fourth embodiment. The main differences between the industrial lens in the fourth embodiment and the industrial lens in the above-mentioned first embodiment lie in the parameters of each lens in the industrial lens and the conditions satisfied, as well as the concavity and convexity of the object side or the image side of each lens at the optical axis.
[0139] Tables 4a to 4d respectively give the specific parameter values of each lens of the industrial lens of an optional embodiment in the fourth embodiment of the present application.
[0140] Table 4a
[0141] Surface Number Surface Type R Value Thickness Refractive Index Abbe Number Sur1 Standard 67.87 9.06 1.83 37.2 Sur2 Standard 287.68 9.44 Sur3 Standard 30.33 5.89 1.59 68.3 Sur4 Standard -126.59 1.18 1.65 39.5 Sur5 Standard 24.78 6.68 STOP Standard Infinity 5.66 Sur7 Standard -58.17 2.48 1.95 17.9 Sur8 Standard -42.34 3.75 Sur9 Standard -32.97 2.42 1.77 29.7 Sur10 Standard 66.54 8.4 1.59 68.3 Sur11 Standard -31.23 2.1 Sur12 Standard -25.49 3.52 1.55 45.8 Sur13 Standard 267.06 7.07 1.83 37.2 Sur14 Standard -37.92 193.04 Image Standard Infinity -
[0142] In the industrial lens of the fourth embodiment, the positive and negative conditions of the optical power of each lens are shown in Table 4b.
[0143] Table 4b
[0144]
[0145] In the industrial lens of the fourth embodiment, the concavity and convexity of the object side or the image side of each lens at the optical axis are shown in Table 4c.
[0146] Table 4c
[0147]
[0148] It can be seen from Table 4a and Table 4b that the second lens L2 in this industrial lens has a positive optical power, and the refractive index and Abbe number of the second lens L2: nd L2 is 1.59, vd L2 is 68.3; the sixth lens L6 has a positive optical power, and the refractive index and Abbe number of the sixth lens L6: nd L6 is 1.59, vd L6 is 68.3.
[0149] The working wavelength range of the industrial lens in this embodiment is 400 - 1000 nm, that is, the visible light and near-infrared wavelength range; the total optical length TTL is 260.69 mm, the focal length f is 114.96 mm, and the absolute value of the lateral magnification |β| is 1.0 times.
[0150] In this embodiment, the first lens L1 of the industrial lens has a positive optical power, and the refractive index temperature coefficient of the first lens L1 at 10 °C to 40 °C: (dndT) L1 = 10.3×10 -6 / °C;
[0151] The eighth lens L8 of the industrial lens has a positive optical power, and the refractive index temperature coefficient of the eighth lens L8 at 10 °C to 40 °C: (dndT) L8 = 10.3×10-6 / °C.
[0152] Combined with Figure 19 The structural schematic diagram of the industrial lens in Embodiment 4, and the main parameters of the industrial lens in Embodiment 4 given in Tables 4a to 4c and the concavity and convexity of each lens at the optical axis. Through simulation, the MTF diagram and the lateral chromatic aberration diagram of the industrial lens in Embodiment 4 in the working wavelength range of 400 - 1000 nm and the temperature range of 10°C to 40°C are obtained, as Figures 20 to 24 shown.
[0153] Combined with Figures 20 to 22 It can be seen that in the industrial lens of this embodiment, in the temperature range of 10°C to 40°C, the image plane offset is small, and confocal imaging is achieved.
[0154] From Figure 23 It can be seen that in the industrial lens of this embodiment, in the working wavelength range of 400 - 1000 nm, the image plane offset is small, and confocal imaging is achieved.
[0155] From Figure 24 It can be seen that the maximum target surface of the industrial lens in this embodiment can reach 82 mm, and the curve slope is small, indicating that the imaging quality of the industrial lens is excellent.
[0156] Combined with Figures 19 to 24 It can be seen that the target surface of the industrial lens in this embodiment can reach 82 mm. In the working wavelength range of 400 - 1000 nm and the temperature range of 10°C to 40°C, the image plane offset is less than 0.15 mm, that is, confocal imaging is achieved in the visible light and near-infrared wavelength ranges, and the imaging quality is excellent.
[0157] In some embodiments, the industrial lens further includes an optical element (not shown in the figure), and the optical element is located between the second lens group G2 and the photosensitive element.
[0158] The above optical element is mainly to achieve a specific imaging effect for the optical element. For example, the optical element can be, but is not limited to, a filter. Through the setting of the filter, the industrial lens transmits light in a specific wavelength range and blocks light in a specific wavelength range, so that the functions of the industrial lens are diversified and specific optical requirements are achieved.
[0159] Table 5 gives the optical parameters of the industrial lenses in the above four embodiments.
[0160] Example 1 Example 2 Example 3 Example 4 <![CDATA[f / f1]]> 0.614 0.507 0.520 0.739 <![CDATA[f / f2]]> 0.810 0.804 0.910 0.751 |β| 0.30 0.50 0.60 1.00
[0161] Note: The following explanatory notes on the relationship of the industrial lenses in each embodiment:
[0162] f is the focal length of the industrial lens;
[0163] f1 is the combined focal length of the first lens group G1;
[0164] f2 is the combined focal length of the second lens group G2;
[0165] β is the lateral magnification of the industrial lens, and |β| is the absolute value of the lateral magnification of the industrial lens.
[0166] From the optical parameters of the industrial lenses in the four embodiments given in Table 5 above, it can be seen that the industrial lens of the present application satisfies the relational expression: 0.5 ≤ f / f1 ≤ 0.75.
[0167] If the ratio f / f1 is too small, the optical power of the first lens group G1 is too large, the incident angle of the light passing through the aperture of the diaphragm STO is relatively large, and the coma and other diaphragm aberrations introduced are too large, resulting in a decline in imaging performance; if the ratio f / f1 is too large, the incident angle of the light passing through the aperture of the diaphragm STO is reduced, improving the imaging quality, but it will cause an increase in the length of the industrial lens, which is not conducive to the miniaturization of the industrial lens.
[0168] By reasonably selecting the above parameters, when the ratio f / f1 satisfies the above relational expression, the optical power of each lens group in the industrial lens can be reasonably adjusted, making the light path smooth, reducing the sensitivity of the industrial lens, maintaining good image quality in the marginal field of view, so as to reduce the length of the industrial lens while improving the imaging quality, which is conducive to the miniaturization of the industrial lens.
[0169] From the optical parameters of the industrial lenses in the four embodiments given in Table 5 above, it can be seen that the industrial lens of the present application satisfies the relational expression: 0.7 ≤ f / f2 ≤ 1.
[0170] If the ratio f / f2 is too small, it can effectively undertake the distribution of the optical power of the system and improve the imaging quality of the industrial lens, but it will cause the length of the industrial lens to be too long; if the ratio f / f2 is too large, it will increase the difficulty of balancing the optical power distribution of the first lens group G1.
[0171] By reasonably selecting the above parameters, when the ratio f / f2 satisfies the above relational expression, it can not only effectively undertake the distribution of the optical power of the system and improve the imaging quality of the industrial lens, but also can well balance the length and conjugate distance of the industrial lens, while ensuring that the optical apertures before and after the system are within a certain range, without the phenomenon of "top-heavy and bottom-light".
[0172] From the optical parameters of the industrial lenses in the above four embodiments, it can be seen that by changing the various optical parameters and the convexity and concavity in the industrial lens, the absolute value |β| of the lateral magnification ratio of the industrial lens of the present application can satisfy the relational expression: 0.3 ≤ |β| ≤ 1.
[0173] In summary, when the target surface of the industrial lens of the present application can reach 82 mm, in the working wavelength range of 400 - 1000 nm and the temperature range of 10 °C to 40 °C, the image plane offset is less than 0.15 mm, that is, the industrial lens achieves confocal imaging in the visible light and near-infrared wavelength ranges, and the imaging quality is excellent.
[0174] It should be noted that the four embodiments of the present application give the structure of an industrial lens including 8 lenses with a "front three and back five" configuration, and the first lens L1 and the eighth lens L8 both have positive optical power. The refractive index temperature coefficient (dn / dT) L8 is 10.3 x 10-6 / °C. That is to say, the first lens L1 and the eighth lens L8 are made of materials that meet the above refractive index temperature coefficient. By adjusting the optical parameters and the convexity and concavity of each lens in the industrial lens, the industrial lens meets the above optical performance requirements. Of course, for other lenses with positive optical power in the industrial lens, such as the second lens L2 and the sixth lens L6, the refractive index temperature coefficient of the materials can also be the above refractive index temperature coefficient, or other refractive index temperature coefficients different from the above can be selected according to needs, and no specific limitation is made here. In addition, on the basis that the optical performance parameters of the industrial lens meet the above requirements, the number of lenses in the industrial lens can also be other numbers, such as 6, 7, 9, 10 ···. When the number of lenses changes, the number and optical power of the lenses in the first lens group G1 and the second lens group G2 need to be adjusted accordingly, and no specific limitation is made here.
[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. An industrial lens, characterized in that, The working frequency band of the industrial lens is 400nm to 1000nm. The industrial lens includes a first lens group and a second lens group arranged from the object side to the image side. The first lens group has a positive optical power, and the second lens group has a positive optical power; The industrial lens includes at least two lenses with positive optical power, and the refractive index temperature coefficient (dn / dT) of the lens with positive optical power Lx satisfies the relational expression at 10°C to 40°C: (dn / dT) Lx ≥10×10 -6 / °C; where n is the refractive index of the x-th lens Lx arranged from the object side to the image side in the industrial lens, and T is the temperature.
2. The industrial lens according to claim 1, wherein The focal length f1 of the first lens group and the focal length f of the industrial lens satisfy the relation: 0.5 ≤ f / f1 ≤ 0.
75.
3. The industrial lens according to claim 1, wherein The focal length f2 of the second lens group and the focal length f of the industrial lens satisfy the relation: 0.7 ≤ f / f2 ≤ 1.
4. The industrial lens according to claim 1, characterized in that The industrial lens includes at least two lenses with positive optical power, and the refractive index nd of the lens with positive optical power Lx and the Abbe number vd Lx satisfy the relational expression: 1.4 ≤ nd Lx ≤ 1.6; 65 ≤ vd Lx ≤ 95.
5.
5. The industrial lens according to claim 1, characterized in that, The absolute value |β| of the lateral magnification of the industrial lens satisfies the relation: 0.3 ≤ |β| ≤ 1.
6. The industrial lens according to any one of claims 1 to 5, characterized in that, The first lens group includes 2 lenses with positive optical power and 1 lens with negative optical power. The second lens group includes 2 lenses with positive optical power and 3 lenses with negative optical power.
7. The industrial lens according to claim 6, wherein The first lens group includes a first lens, a second lens, and a third lens arranged from the object side to the image side. The first lens and the second lens have positive optical power, and the third lens has negative optical power; The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged from the object side to the image side. The sixth lens and the eighth lens have positive optical power, and the fourth lens, the fifth lens, and the seventh lens have negative optical power.
8. The industrial lens according to claim 7, wherein The second lens and the third lens form a cemented lens; the fifth lens and the sixth lens form a cemented lens, and / or, the seventh lens and the eighth lens form a cemented lens.
9. The industrial lens according to any one of claims 1 to 5, characterized in that The industrial lens further includes a diaphragm, and the diaphragm is located between the first lens and the second lens.
10. A camera module, characterized in that, Comprising: The industrial lens according to any one of claims 1 to 9.