Imaging system

Abstract

This application discloses an imaging system comprising, along the optical axis from the object side to the image side, a first lens group having positive optical power and a second lens group having positive optical power. The first lens group 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, and a ninth lens. The second lens group includes a tenth lens. The imaging system also includes an aperture stop located between the fifth and sixth lenses; the position of the first lens group along the optical axis is adjustable; and the imaging system satisfies: 0.65 ≤ f2 / f1 ≤ 1.86.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to an imaging system. Background Technology

[0002] Machine vision refers to using machines to replace human eyes for measurement and judgment. In machine vision applications, an imaging system (such as a lens) mounted on the machine captures images. An image acquisition device (such as an industrial camera) converts the captured images into image signals, and transmits these signals, such as position, size, and appearance, to an image processing system. The image processing system outputs the acquired results according to preset conditions to achieve functions such as automatic recognition, judgment, and measurement.

[0003] Therefore, imaging systems play a crucial role in machine vision applications, with their pixel count, image uniformity, distortion, brightness, and color reproduction directly impacting the quality of the system. However, current imaging systems used in machine vision generally suffer from at least one of the following problems: small image size, significant distortion, uneven image sharpness, limited working distance range, large transmittance deviation, and significant susceptibility to temperature fluctuations. Consequently, the application areas of current imaging systems are somewhat limited, especially in high-precision, high-tech fields where they cannot fully realize their intended functions. Summary of the Invention

[0004] This application provides an imaging system comprising, along the optical axis from the object side to the image side, a first lens group with positive optical power and a second lens group with positive optical power. The first lens group 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, and a ninth lens. The second lens group includes a tenth lens. The imaging system also includes an aperture stop located between the fifth and sixth lenses; the position of the first lens group along the optical axis is adjustable; and the imaging system satisfies: 0.65 ≤ f2 / f1 ≤ 1.86, where f1 is the effective focal length of the first lens group and f2 is the effective focal length of the second lens group.

[0005] In one embodiment, the first lens, the fourth lens, the fifth lens, the sixth lens, and the eighth lens all have positive optical power; and the second lens, the third lens, the seventh lens, and the ninth lens all have negative optical power.

[0006] In one embodiment, the tenth lens has positive optical power.

[0007] In one embodiment, the object-side surface of the first lens is convex and the image-side surface is concave; the object-side surface of the second lens is convex and the image-side surface is concave; the object-side surface of the third lens is concave and the image-side surface is concave; the object-side surface of the fourth lens is convex and the image-side surface is convex; the object-side surface of the fifth lens is convex; the object-side surface of the sixth lens is convex and the image-side surface is convex; the object-side surface of the seventh lens is concave and the image-side surface is concave; the object-side surface of the eighth lens is convex and the image-side surface is convex; and the object-side surface of the ninth lens is concave.

[0008] In one embodiment, the image-side surface of the tenth lens is convex.

[0009] In one embodiment, at least two cemented lenses include: a sixth lens and a seventh lens cemented together to form a first cemented lens; and an eighth lens and a ninth lens cemented together to form a second cemented lens.

[0010] In one embodiment, the third lens and the fourth lens are cemented together to form a third cemented lens.

[0011] In one embodiment, the imaging system may satisfy: 1.30≤f1 / f≤1.89, where f1 is the effective focal length of the first lens group and f is the total effective focal length of the imaging system when it is in the intermediate state.

[0012] In one implementation, the imaging system may satisfy: 0.93 ≤ f 12 / f 13 ≤1.81, where f 12 It is the effective focal length of the second lens, f 13 It is the effective focal length of the third lens.

[0013] In one embodiment, at least one of the lenses having positive optical power in the first cemented lens and the second cemented lens satisfies: 59.3 ≤ Vd + ≤86.1 and 1.47≤Nd + ≤1.65, where Vd + It is the Abbe number of at least one lens, Nd + It is the refractive index of at least one lens.

[0014] In one embodiment, at least one of the lenses having positive optical power among the first cemented lens, the second cemented lens, and the third cemented lens satisfies: 59.3 ≤ Vd + ≤86.1 and 1.47≤Nd + ≤1.65, where Vd + It is the Abbe number of at least one lens, Nd + It is the refractive index of at least one lens.

[0015] In one implementation, the imaging system may satisfy: 1.62 ≤ Nd L2 ≤1.92 and 36.4≤Vd L2 ≤65.0, where Nd L2 Vd is the refractive index of the second lens. L2 It is the Abbe number of the second lens.

[0016] In one embodiment, the imaging system may satisfy: -0.81≤f9 / f≤-0.36, where f9 is the effective focal length of the ninth lens and f is the total effective focal length of the imaging system when it is in the intermediate state.

[0017] In one embodiment, the imaging system may satisfy: 0.33≤Y / TTL≤0.38, where Y is the image height corresponding to the maximum field of view when the imaging system is in the intermediate state, and TTL is the distance on the optical axis from the center of the object side of the first lens to the imaging surface of the imaging system when the imaging system is in the intermediate state.

[0018] In the exemplary embodiments of this application, by reasonably setting the lens composition of the first lens group and the second lens group, as well as the optical power of each lens group and each lens, the position of the first lens group, and the main technical parameters, the imaging system provided by this application can have at least one of the following beneficial effects: large target area, low distortion, uniform image quality, wide working distance range, and good temperature performance. Attached Figure Description

[0019] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of the imaging system according to Embodiment 1 of this application in an intermediate state during the process of switching from the initial state to the final state.

[0021] Figures 2A to 2C The modulation transfer function (MTF) curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve of the imaging system of Example 1 in an intermediate state are shown respectively.

[0022] Figure 3 This is a schematic diagram of the imaging system according to Embodiment 2 of this application in an intermediate state during the process of switching from the initial state to the final state;

[0023] Figures 4A to 4C The modulation transfer function (MTF) curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve of the imaging system in Example 2 when it is in an intermediate state are shown respectively.

[0024] Figure 5This is a schematic diagram of the imaging system according to Embodiment 3 of this application in an intermediate state during the process of switching from the initial state to the final state;

[0025] Figures 6A to 6C The modulation transfer function (MTF) curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve of the imaging system in Example 3 when it is in an intermediate state are shown respectively.

[0026] Figure 7 This is a schematic diagram of the imaging system according to Embodiment 4 of this application during an intermediate state in the process of switching from the initial state to the final state; and

[0027] Figures 8A to 8C The modulation transfer function (MTF) curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve of the imaging system in Example 4 are shown respectively when it is in an intermediate state. Detailed Implementation

[0028] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0029] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0030] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0031] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0032] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0033] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] The features, principles and other aspects of this application are described in detail below.

[0036] An imaging system according to an exemplary embodiment of this application may include two lens groups with optical power, namely a first lens group and a second lens group. These two lens groups are arranged sequentially along the optical axis from the object side to the image side. The first lens group may include nine lenses with optical power, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. These nine lenses are arranged sequentially along the optical axis from the object side to the image side. The second lens group may include one lens with optical power, such as a tenth lens.

[0037] In an exemplary embodiment, the position of the first lens group along the optical axis is adjustable to enable continuous zooming of the imaging system. Specifically, by changing the position of the first lens group on the optical axis, the imaging system can switch from an initial state to a final state or vice versa, thus enabling continuous zooming. For example, the focal length of the imaging system is adjusted by regulating the distance between the ninth and tenth lenses on the optical axis, allowing the imaging system to achieve an optimal imaging position and thus enabling continuous zooming, ensuring clear imaging at different distances from the subject.

[0038] In this application, the initial state of the imaging system can be the state when the imaging system is closest to the object (compared to the state when it is farthest from the object). The final state of the imaging system can be the state when the imaging system is farthest from the object (compared to the state when it is closest to the object). The state of the imaging system between the initial state and the final state is the intermediate state of the imaging system. For example, the initial state of the imaging system can be the state when the imaging system is 700mm away from the object, the intermediate state of the imaging system can be the state when the imaging system is 1000mm away from the object, and the final state of the imaging system can be the state when the imaging system is infinitely far away from the object.

[0039] In an exemplary embodiment, the first lens group may have positive optical power; the second lens group may have positive optical power. Exemplarily, the first lens may have positive optical power; the second lens may have negative optical power; the third lens may have negative optical power; the fourth lens may have positive optical power; the fifth lens may have positive optical power; the sixth lens may have positive optical power; the seventh lens may have negative optical power; the eighth lens may have positive optical power; the ninth lens may have negative optical power; and the tenth lens may have positive optical power. This application, by reasonably setting the optical power of each lens, facilitates the imaging system's ability to better correct optical aberrations and distortions at different distances from the subject. This allows incident light rays to pass through the surfaces of each lens sequentially at smaller angles, reducing the system's tolerance sensitivity and improving image uniformity. Exemplarily, by setting the first lens to have positive optical power and the second lens to have negative optical power, this application can effectively control the incident angle of light, reduce system aberrations and tolerances, and improve the imaging quality of the imaging system.

[0040] In an exemplary embodiment, the object-side surface of the first lens may be convex, and the image-side surface may be concave; the object-side surface of the second lens may be convex, and the image-side surface may be concave; the object-side surface of the third lens may be concave, and the image-side surface may be concave; the object-side surface of the fourth lens may be convex, and the image-side surface may be convex; the object-side surface of the fifth lens may be convex, and the image-side surface may be either convex or concave; the object-side surface of the sixth lens may be convex, and the image-side surface may be convex; the object-side surface of the seventh lens may be concave, and the image-side surface may be concave; the object-side surface of the eighth lens may be convex, and the image-side surface may be convex; the object-side surface of the ninth lens may be concave, and the image-side surface may be either convex or concave; and the object-side surface of the tenth lens may be either convex or concave, and the image-side surface may be convex. This application, by reasonably setting the optical power and surface features of each lens, is beneficial for correcting system distortion and aberrations, and improving the system's imaging quality.

[0041] In an exemplary embodiment, at least two lenses in the first lens group can be cemented together to form a cemented lens. The first lens group may include at least two cemented lenses. In one exemplary embodiment, the first lens group may include a first cemented lens formed by cementing a sixth and a seventh lens, and a second cemented lens formed by cementing an eighth and a ninth lens. In another exemplary embodiment, the first lens group may include a first cemented lens formed by cementing a sixth and a seventh lens, a second cemented lens formed by cementing an eighth and a ninth lens, and a third cemented lens formed by cementing a third and a fourth lens. In this application, by providing cemented lenses, it is beneficial to correct various aberrations of the imaging system, reduce the sensitivity of lens fit, and improve resolution. Exemplarily, the fifth lens and the first cemented lens can be combined to form a Gaussian structure, which can effectively reduce the incident angle of light to reduce tolerance sensitivity and also effectively correct distortion.

[0042] In one exemplary embodiment, the imaging system according to this application satisfies: 0.65 ≤ f2 / f1 ≤ 1.86, where f1 is the effective focal length of the first lens group and f2 is the effective focal length of the second lens group. By reasonably setting f2 and f1, this application facilitates adjusting the focal length of the imaging system at different distances from the subject, ensuring clear imaging at all distances, reducing field curvature, guaranteeing image quality, and balancing the tolerance sensitivity between the first and second lens groups.

[0043] In one exemplary embodiment, the imaging system according to this application satisfies: 1.30 ≤ f1 / f ≤ 1.89, where f1 is the effective focal length of the first lens group, and f is the total effective focal length of the imaging system in the intermediate state. By reasonably setting f and f1, this application facilitates adjusting the focal length of the imaging system at different distances from the subject, ensuring clear imaging at all distances, reducing field curvature, guaranteeing image quality, and balancing the tolerance sensitivity between the first and second lens groups.

[0044] In one exemplary embodiment, the imaging system according to this application satisfies: 0.93 ≤ f 12 / f 13 ≤1.81, where f 12 It is the effective focal length of the second lens, f 13 It is the effective focal length of the third lens. This application achieves this by reasonably setting f. 12 and f 13 This helps to reduce the angle of refraction of incident light and decrease tolerance sensitivity.

[0045] In one exemplary embodiment, at least one of the lenses having positive optical power in the first and second cemented lenses (such as the sixth and eighth lenses) can satisfy: 59.3 ≤ Vd + ≤86.1 and 1.47≤Nd + ≤1.65, where Vd + It is the Abbe number of at least one lens, Nd + It is the refractive index of at least one lens. For example, the eighth lens can satisfy: 59.3 ≤ Vd + ≤86.1 and 1.47≤Nd + ≤1.65, where Vd + It is the Abbe number of the eighth lens, Nd + This refers to the refractive index of the eighth lens. By reasonably setting the refractive index and Abbe number of at least one of the sixth and eighth lenses to meet the above-mentioned range, this application can effectively correct the chromatic aberration of the imaging system, thereby improving the imaging quality of the imaging system. At the same time, it can also improve the temperature correction capability of the system, enabling the imaging system to produce clear images over a wide temperature range.

[0046] In one exemplary embodiment, at least one of the lenses having positive optical power among the first cemented lens, the second cemented lens, and the third cemented lens (such as the fourth lens, the sixth lens, and the eighth lens) can satisfy: 59.3 ≤ Vd + ≤86.1 and 1.47≤Nd + ≤1.65, where Vd + It is the Abbe number of at least one lens, Nd + It is the refractive index of at least one lens. For example, the eighth lens can satisfy: 59.3 ≤ Vd + ≤86.1 and 1.47≤Nd + ≤1.65, where Vd + It is the Abbe number of the eighth lens, Nd + This refers to the refractive index of the eighth lens. By reasonably setting the refractive index and Abbe number of at least one of the fourth, sixth, and eighth lenses to meet the above-mentioned range, this application can effectively correct the chromatic aberration of the imaging system, thereby improving the imaging quality of the imaging system. At the same time, it can also improve the temperature correction capability of the system, enabling the imaging system to produce clear images over a wide temperature range.

[0047] In one exemplary embodiment, the imaging system according to this application satisfies: 1.62 ≤ Nd L2 ≤1.92 and 36.4≤Vd L2 ≤65.0, where Nd L2 Vd is the refractive index of the second lens. L2This refers to the Abbe number of the second lens. By rationally setting the refractive index and Abbe number of the second lens, this application can better compensate for on-axis aberrations of the imaging system and further improve imaging quality.

[0048] In one exemplary embodiment, the imaging system according to this application satisfies: -0.81 ≤ f9 / f ≤ -0.36, where f9 is the effective focal length of the ninth lens, and f is the total effective focal length of the imaging system in the intermediate state. By reasonably setting f9 and f, this application facilitates the imaging system to have characteristics such as a large back focal length and a large target surface.

[0049] In one exemplary embodiment, the imaging system according to this application satisfies: 0.33 ≤ Y / TTL ≤ 0.38, where Y is the image height corresponding to the maximum field of view when the imaging system is in its intermediate state, and TTL is the distance on the optical axis from the center of the object side of the first lens to the imaging surface of the imaging system when the imaging system is in its intermediate state. This application, by reasonably setting Y and TTL, facilitates the achievement of imaging quality for larger target surfaces. Otherwise, if Y / TTL is too large, it is difficult to guarantee the image quality of a large target surface; if Y / TTL is too small, the imaging image surface will be small.

[0050] In an exemplary embodiment, the imaging system according to this application further includes an aperture stop disposed between the fifth lens and the sixth lens. Optionally, the imaging system may also include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface. This application can adjust the focal length of the imaging system by adjusting the distance between the ninth and tenth lenses on the optical axis, thereby enabling the imaging system to have a better imaging position and achieving continuous zoom, so that the imaging system can achieve clear imaging at different distances from the subject. This application proposes an imaging system with characteristics such as continuous zoom, smooth image transition during zooming, large target area, small distortion, uniform image quality, wide working distance range, good temperature performance, and high imaging quality. For example, the imaging system provided by this application can achieve clear imaging at distances from the subject from 700mm to infinity, and can achieve clear imaging when used in a temperature range of -20℃ to 70℃. The imaging system according to the above embodiments of this application can use multiple lenses, such as the ten lenses mentioned above. By rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis spacing between each lens, incident light rays can be effectively converged, the overall optical length of the imaging lens can be reduced, and the manufacturability of the imaging lens can be improved, making the imaging system more conducive to production and processing.

[0051] However, those skilled in the art will understand that the number of lenses constituting the imaging system can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although ten lenses are described as an example in the embodiments, the imaging system is not limited to including ten lenses. If desired, the imaging system may also include other numbers of lenses.

[0052] Specific embodiments of the imaging system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0053] Example 1

[0054] The following is for reference Figures 1 to 2C An imaging system according to Embodiment 1 of this application is described. Figure 1 This is a schematic diagram of the imaging system according to Embodiment 1 of this application in an intermediate state (e.g., 1000mm away from the object) during the process of switching from the initial state to the final state.

[0055] like Figure 1 As shown, the imaging system includes, in sequence from the object side to the image side: a first lens group G1 (first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, aperture STO, sixth lens L6, seventh lens L7, eighth lens L8 and ninth lens L9), a second lens group G2 (tenth lens L10), a filter and / or protective glass CG, and an imaging surface.

[0056] The first lens L1 has positive optical power, with a convex object-side surface and a concave image-side surface. The second lens L2 has negative optical power, with a convex object-side surface and a concave image-side surface. The third lens L3 has negative optical power, with a concave object-side surface and a concave image-side surface. The fourth lens L4 has positive optical power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has positive optical power, with a convex object-side surface and a convex image-side surface. The sixth lens L6 has positive optical power, with a convex object-side surface and a convex image-side surface. The seventh lens L7 has negative optical power, with a concave object-side surface and a concave image-side surface. The eighth lens L8 has positive optical power, with a convex object-side surface and a convex image-side surface. The ninth lens L9 has negative optical power, with a concave object-side surface and a convex image-side surface. The tenth lens L10 has positive optical power, with a concave object-side surface and a convex image-side surface. The sixth lens L6 and the seventh lens L7 can be cemented together to form a first cemented lens. The eighth lens L8 and the ninth lens L9 can be cemented together to form a second cemented lens. Light from the object passes sequentially through each surface (i.e., sequentially through the object-side surface of the first lens L1 to the image-side surface of the filter and / or protective glass CG) and is finally imaged on the imaging surface, where an image sensor chip IMA can be disposed. The filter and / or protective glass can be used to correct color deviation and / or protect the image sensor chip IMA located on the imaging surface.

[0057] Table 1 shows the basic parameters of the imaging system of Example 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0058]

[0059]

[0060] Table 1

[0061] In this example, surface 11 is the object-side surface of the first lens, and surface 12 is the image-side surface of the first lens. Surface 21 is the object-side surface of the second lens, and surface 22 is the image-side surface of the second lens. Surface 31 is the object-side surface of the third lens, and surface 32 is the image-side surface of the third lens. Surface 41 is the object-side surface of the fourth lens, and surface 42 is the image-side surface of the fourth lens. Surface 51 is the object-side surface of the fifth lens, and surface 52 is the image-side surface of the fifth lens. Surface 61 is the object-side surface of the sixth lens, and surface 62 is the image-side surface of the sixth lens. Surface 71 is the object-side surface of the seventh lens, and surface 72 is the image-side surface of the seventh lens. Surface 81 is the object-side surface of the eighth lens, and surface 82 is the image-side surface of the eighth lens. Surface 91 is the object-side surface of the ninth lens, and surface 92 is the image-side surface of the ninth lens. Surface 101 is the object-side surface of the tenth lens, and surface 102 is the image-side surface of the tenth lens. Surface 111 is the object-side surface of the filter, and surface 112 is the image-side surface of the filter.

[0062] In this example, by changing the position of the first lens group on the optical axis, the total effective focal length of the imaging system can change with the distance from the subject, thus achieving continuous zoom. In other words, by changing the distance D between the first and second lens groups on the optical axis (i.e., the air gap between the ninth lens L9 and the tenth lens L10 on the optical axis), the imaging system can be sequentially switched from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. The total effective focal length f, the maximum half field of view HFOV, and the aperture value Fno of the imaging system change as the imaging system sequentially switches from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. In this example, the initial state of the imaging system can be the state when the imaging system is 700mm away from the subject, the intermediate state can be the state when the imaging system is 1000mm away from the subject, and the final state can be the state when the imaging system is at infinity away from the subject.

[0063] Table 2 shows the total effective focal length f, the maximum half field of view HFOV, the aperture value Fno, and the specific parameter values ​​of the air gap D between the ninth and tenth lenses on the optical axis when the imaging system of Example 1 is in the intermediate state. Here, the units of f and D are millimeters (mm), and the unit of HFOV is degrees (°).

[0064] Status / Parameters f HFOV Fno D intermediate state 34.8 31.46 4.06 14.55

[0065] Table 2

[0066] In this example, when the imaging system is in its initial state, the air gap D between the ninth and tenth lenses on the optical axis is 15.65 mm; when the imaging system is in its final state, the air gap D between the ninth and tenth lenses on the optical axis is 12.08 mm.

[0067] Figure 2A The modulation transfer function (MTF) curves of the imaging system in Example 1 in the 0.449μm to 0.680μm band are shown when the imaging system is in the intermediate state (i.e., 1000mm away from the subject). These curves represent the pixel size in the meridional and sagittal fields of view at different frequencies. Figure 2B The image system of Example 1 is shown in an intermediate state, with an on-axis chromatic aberration curve in the 0.449μm to 0.680μm band, which indicates the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 2CThe image system of Example 1 is shown in its intermediate state, exhibiting field curvature and distortion curves within the 0.449 μm to 0.680 μm band. The field curvature represents the meridional and sagittal image plane curvature, while the distortion curves represent the distortion magnitudes corresponding to different image heights. According to... Figures 2A to 2C It can be seen that the imaging system given in Example 1 can achieve good imaging quality in the intermediate state.

[0068] Example 1 only exemplifies the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in an intermediate state. To avoid redundancy, the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in the initial and final states are not listed. It should be understood that the imaging system provided in Example 1 of this application can achieve good imaging quality in all states.

[0069] Example 2

[0070] The following is for reference Figures 3 to 4C An imaging system according to Embodiment 2 of this application is described. In this embodiment and the following embodiments, for the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted. Figure 3 A schematic diagram of the structure of the imaging system according to Embodiment 2 of this application is shown in an intermediate state (e.g., 1000 mm away from the object) during the process of switching from the initial state to the final state.

[0071] like Figure 3 As shown, the imaging system includes, in sequence from the object side to the image side: a first lens group G1 (first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, aperture STO, sixth lens L6, seventh lens L7, eighth lens L8 and ninth lens L9), a second lens group G2 (tenth lens L10), a filter and / or protective glass CG, and an imaging surface.

[0072] Lens L1 has positive optical power, with a convex object-side and a concave image-side. Lens L2 has negative optical power, with a convex object-side and a concave image-side. Lens L3 has negative optical power, with a concave object-side and a concave image-side. Lens L4 has positive optical power, with a convex object-side and a convex image-side. Lens L5 has positive optical power, with a convex object-side and a concave image-side. Lens L6 has positive optical power, with a convex object-side and a convex image-side. Lens L7 has negative optical power, with a concave object-side and a concave image-side. Lens L8 has positive optical power, with a convex object-side and a convex image-side. Lens L9 has negative optical power, with a concave object-side and a concave image-side. Lens L10 has positive optical power, with a convex object-side and a convex image-side. The sixth lens L6 and the seventh lens L7 can be cemented together to form a first cemented lens. The eighth lens L8 and the ninth lens L9 can be cemented together to form a second cemented lens. The third lens L3 and the fourth lens L4 can be cemented together to form a third cemented lens. Light from the object passes sequentially through each surface (i.e., sequentially through the object-side surface of the first lens L1 to the image-side surface of the filter and / or protective glass CG) and is finally imaged on the imaging surface, where an image sensor chip (IMA) can be disposed. The filter and / or protective glass can be used to correct color deviation and / or protect the image sensor chip (IMA) located on the imaging surface.

[0073] Table 3 shows the basic parameters of the imaging system of Example 2, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0074]

[0075] Table 3

[0076] In this example, by changing the position of the first lens group on the optical axis, the total effective focal length of the imaging system can change with the distance from the subject, thus achieving continuous zoom. In other words, by changing the distance D between the first and second lens groups on the optical axis (i.e., the air gap between the ninth lens L9 and the tenth lens L10 on the optical axis), the imaging system can be sequentially switched from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. The total effective focal length f, the maximum half field of view HFOV, and the aperture value Fno of the imaging system change as the imaging system sequentially switches from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. In this example, the initial state of the imaging system can be the state when the imaging system is 700mm away from the subject, the intermediate state can be the state when the imaging system is 1000mm away from the subject, and the final state can be the state when the imaging system is at infinity away from the subject.

[0077] Table 4 shows the total effective focal length f, the maximum half field of view HFOV, the aperture value Fno, and the air gap D between the ninth and tenth lenses on the optical axis of the imaging system in the intermediate state of the imaging system in Example 2. The units of f and D are millimeters (mm), and the unit of HFOV is degrees (°).

[0078] Status / Parameters f HFOV Fno D intermediate state 34.62 31.53 4.07 13.02

[0079] Table 4

[0080] In this example, when the imaging system is in its initial state, the air gap D between the ninth and tenth lenses on the optical axis is 14.77 mm; when the imaging system is in its final state, the air gap D between the ninth and tenth lenses on the optical axis is 8.94 mm.

[0081] Figure 4A The modulation transfer function (MTF) curves of the imaging system in Example 2 are shown in the 0.449μm to 0.680μm band when the imaging system is in the intermediate state (i.e., 1000mm away from the subject). These curves represent the pixel size in the meridional and sagittal fields of view at different frequencies. Figure 4B The on-axis chromatic aberration curve of the imaging system in the 0.449μm to 0.680μm band is shown when the imaging system of Example 2 is in the intermediate state. It shows the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 4C The image system of Example 2 is shown in its intermediate state, exhibiting field curvature and distortion curves within the 0.449 μm to 0.680 μm band. The field curvature represents the meridional and sagittal image plane curvature, while the distortion curves represent the distortion magnitudes corresponding to different image heights. According to... Figures 4A to 4C It can be seen that the imaging system given in Example 2 can achieve good imaging quality in the intermediate state.

[0082] Example 2 only exemplifies the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in an intermediate state. To avoid redundancy, the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in the initial and final states are not listed. It should be understood that the imaging system provided in Example 1 of this application can achieve good imaging quality in all states.

[0083] Example 3

[0084] The following is for reference Figures 5 to 6C An imaging system according to Embodiment 3 of this application is described. Figure 5This is a schematic diagram of the imaging system according to Embodiment 3 of this application in an intermediate state (e.g., 1000mm away from the object being photographed) during the process of switching from the initial state to the final state.

[0085] like Figure 5 As shown, the imaging system includes, in sequence from the object side to the image side: a first lens group G1 (first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, aperture STO, sixth lens L6, seventh lens L7, eighth lens L8 and ninth lens L9), a second lens group G2 (tenth lens L10), a filter and / or protective glass CG, and an imaging surface.

[0086] The first lens L1 has positive optical power, with a convex object-side surface and a concave image-side surface. The second lens L2 has negative optical power, with a convex object-side surface and a concave image-side surface. The third lens L3 has negative optical power, with a concave object-side surface and a concave image-side surface. The fourth lens L4 has positive optical power, with a convex object-side surface and a convex image-side surface. The fifth lens L5 has positive optical power, with a convex object-side surface and a concave image-side surface. The sixth lens L6 has positive optical power, with a convex object-side surface and a convex image-side surface. The seventh lens L7 has negative optical power, with a concave object-side surface and a concave image-side surface. The eighth lens L8 has positive optical power, with a convex object-side surface and a convex image-side surface. The ninth lens L9 has negative optical power, with a concave object-side surface and a convex image-side surface. The tenth lens L10 has positive optical power, with a convex object-side surface and a convex image-side surface. The sixth lens L6 and the seventh lens L7 can be cemented together to form a first cemented lens. The eighth lens L8 and the ninth lens L9 can be cemented together to form a second cemented lens. The third lens L3 and the fourth lens L4 can be cemented together to form a third cemented lens. Light from the object passes sequentially through each surface (i.e., sequentially through the object-side surface of the first lens L1 to the image-side surface of the filter and / or protective glass CG) and is finally imaged on the imaging surface, where an image sensor chip (IMA) can be disposed. The filter and / or protective glass can be used to correct color deviation and / or protect the image sensor chip (IMA) located on the imaging surface.

[0087] Table 5 shows the basic parameters of the imaging system of Example 3, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0088]

[0089] Table 5

[0090] In this example, by changing the position of the first lens group on the optical axis, the total effective focal length of the imaging system can change with the distance from the subject, thus achieving continuous zoom. In other words, by changing the distance D between the first and second lens groups on the optical axis (i.e., the air gap between the ninth lens L9 and the tenth lens L10 on the optical axis), the imaging system can be sequentially switched from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. The total effective focal length f, the maximum half field of view HFOV, and the aperture value Fno of the imaging system change as the imaging system sequentially switches from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. In this example, the initial state of the imaging system can be the state when the imaging system is 700mm away from the subject, the intermediate state can be the state when the imaging system is 1000mm away from the subject, and the final state can be the state when the imaging system is at infinity away from the subject.

[0091] Table 6 shows the total effective focal length f, the maximum half field of view HFOV, the aperture value Fno, and the air gap D between the ninth and tenth lenses on the optical axis of the imaging system in the intermediate state of the imaging system in Example 3. The units of f and D are millimeters (mm), and the unit of HFOV is degrees (°).

[0092] Status / Parameters f HFOV Fno D intermediate state 34.68 31.46 4.06 12.49

[0093] Table 6

[0094] In this example, when the imaging system is in its initial state, the air gap D between the ninth and tenth lenses on the optical axis is 14.22 mm; when the imaging system is in its final state, the air gap D between the ninth and tenth lenses on the optical axis is 9.02 mm.

[0095] Figure 6A The modulation transfer function (MTF) curves of the imaging system in Example 3 in the 0.449μm to 0.680μm band are shown when the imaging system is in the intermediate state (i.e., 1000mm away from the subject). These curves represent the pixel size in the meridional and sagittal fields of view at different frequencies. Figure 6B The image system of Example 3 is shown in an intermediate state, with an on-axis chromatic aberration curve in the 0.449μm to 0.680μm band, which shows the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 6CThe image system of Example 3 is shown in its intermediate state, exhibiting field curvature and distortion curves within the 0.449μm to 0.680μm band. The field curvature represents the meridional and sagittal image plane curvature, while the distortion curves represent the distortion magnitudes corresponding to different image heights. According to... Figures 6A to 6C It can be seen that the imaging system given in Example 3 can achieve good imaging quality in the intermediate state.

[0096] Example 3 only exemplifies the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in an intermediate state. To avoid redundancy, the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in the initial and final states are not listed. It should be understood that the imaging system provided in Example 1 of this application can achieve good imaging quality in all states.

[0097] Example 4

[0098] The following is for reference Figures 7 to 8C An imaging system according to Embodiment 4 of this application is described. Figure 7 A schematic diagram of the structure of the imaging system according to Embodiment 4 of this application is shown in an intermediate state (e.g., 1000 mm away from the object) during the process of switching from the initial state to the final state.

[0099] like Figure 7 As shown, the imaging system includes, in sequence from the object side to the image side: a first lens group G1 (first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, aperture STO, sixth lens L6, seventh lens L7, eighth lens L8 and ninth lens L9), a second lens group G2 (tenth lens L10), a filter and / or protective glass CG, and an imaging surface.

[0100] Lens L1 has positive optical power, with a convex object-side and a concave image-side. Lens L2 has negative optical power, with a convex object-side and a concave image-side. Lens L3 has negative optical power, with a concave object-side and a concave image-side. Lens L4 has positive optical power, with a convex object-side and a convex image-side. Lens L5 has positive optical power, with a convex object-side and a concave image-side. Lens L6 has positive optical power, with a convex object-side and a convex image-side. Lens L7 has negative optical power, with a concave object-side and a concave image-side. Lens L8 has positive optical power, with a convex object-side and a convex image-side. Lens L9 has negative optical power, with a concave object-side and a convex image-side. Lens L10 has positive optical power, with a concave object-side and a convex image-side. The sixth lens L6 and the seventh lens L7 can be cemented together to form a first cemented lens. The eighth lens L8 and the ninth lens L9 can be cemented together to form a second cemented lens. The third lens L3 and the fourth lens L4 can be cemented together to form a third cemented lens. Light from the object passes sequentially through each surface (i.e., sequentially through the object-side surface of the first lens L1 to the image-side surface of the filter and / or protective glass CG) and is finally imaged on the imaging surface, where an image sensor chip (IMA) can be disposed. The filter and / or protective glass can be used to correct color deviation and / or protect the image sensor chip (IMA) located on the imaging surface.

[0101] Table 7 shows the basic parameters of the imaging system of Example 4, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0102]

[0103] Table 7

[0104] In this example, by changing the position of the first lens group on the optical axis, the total effective focal length of the imaging system can change with the distance from the subject, thus achieving continuous zoom. In other words, by changing the distance D between the first and second lens groups on the optical axis (i.e., the air gap between the ninth lens L9 and the tenth lens L10 on the optical axis), the imaging system can be sequentially switched from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. The total effective focal length f, the maximum half field of view HFOV, and the aperture value Fno of the imaging system change as the imaging system sequentially switches from the initial state to the intermediate state, the final state, or from the final state to the intermediate state and the initial state. In this example, the initial state of the imaging system can be the state when the imaging system is 700mm away from the subject, the intermediate state can be the state when the imaging system is 1000mm away from the subject, and the final state can be the state when the imaging system is at infinity away from the subject.

[0105] Table 8 shows the total effective focal length f, the maximum half field of view HFOV, the aperture value Fno, and the air gap D between the ninth and tenth lenses on the optical axis of the imaging system in the intermediate state of the imaging system of Example 4. The units of f and D are millimeters (mm), and the unit of HFOV is degrees (°).

[0106] Status / Parameters f HFOV Fno D intermediate state 34.76 31.37 4.06 15.17

[0107] Table 8

[0108] In this example, when the imaging system is in its initial state, the air gap D between the ninth and tenth lenses on the optical axis is 16.37 mm; when the imaging system is in its final state, the air gap D between the ninth and tenth lenses on the optical axis is 12.32 mm.

[0109] Figure 8A The modulation transfer function (MTF) curves of the imaging system in Example 4 are shown in the 0.449μm to 0.680μm band range when the imaging system is in the intermediate state (i.e., 1000mm away from the subject). These curves represent the pixel size in the meridional and sagittal fields of view at different frequencies. Figure 8B The image system of Example 4 is shown in an intermediate state, with an on-axis chromatic aberration curve in the 0.449μm to 0.680μm band, which indicates the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 8C The image system of Example 4 is shown in its intermediate state, exhibiting field curvature and distortion curves within the 0.449μm to 0.680μm band. The field curvature represents the meridional and sagittal image plane curvature, while the distortion curves represent the distortion magnitude corresponding to different image heights. According to... Figures 8A to 8C It can be seen that the imaging system given in Example 4 can achieve good imaging quality in the intermediate state.

[0110] Example 4 only exemplifies the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in an intermediate state. To avoid redundancy, the MTF curve, on-axis chromatic aberration curve, field curvature curve, and distortion curve when the imaging system is in the initial and final states are not listed. It should be understood that the imaging system provided in Example 1 of this application can achieve good imaging quality in all states.

[0111] In summary, Examples 1 to 4 satisfy the relationships shown in Table 9.

[0112]

[0113]

[0114] Table 9

[0115] This application also provides an imaging device, wherein the electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a machine vision system, or an imaging module integrated into a mobile electronic device such as a machine vision system. The imaging device is equipped with the imaging system described above.

[0116] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An imaging system, characterized by, sequentially from the object side to the image side along the optical axis comprises: a first lens group with positive refractive power, the first lens group comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens; a second lens group with positive refractive power, comprising a tenth lens; the imaging system further comprises a stop between the fifth lens and the sixth lens; wherein the number of lenses with refractive power in the first lens group is nine; the number of lenses with refractive power in the second lens group is one; the first lens, the fourth lens, the fifth lens, the sixth lens and the eighth lens all have positive refractive power; the second lens, the third lens, the seventh lens and the ninth lens all have negative refractive power; the tenth lens has positive refractive power; the position of the first lens group along the optical axis is adjustable; and the imaging system satisfies: 0.65≤f2 / f1≤1.86, wherein f1 is the effective focal length of the first lens group, and f2 is the effective focal length of the second lens group.

2. The imaging system according to claim 1, wherein: the sixth lens and the seventh lens are cemented to form a first cemented lens; and the eighth lens and the ninth lens are cemented to form a second cemented lens.

3. The imaging system of claim 2, wherein, the third lens and the fourth lens are cemented to form a third cemented lens.

4. The imaging system of claim 1, wherein, the imaging system satisfies: 1.30≤f1 / f≤1.89, wherein f1 is the effective focal length of the first lens group, and f is the total effective focal length of the imaging system in the intermediate state.

5. The imaging system of claim 1, wherein, The imaging system satisfies: 0.93 ≤ f 12 / f 13 ≤ 1.81, where f 12 is the effective focal length of the second lens, and f 13 is the effective focal length of the third lens.

6. The imaging system of claim 2, wherein, At least one of the lenses having positive refractive power among the first cemented lens and the second cemented lens satisfies: 59.3 ≤ Vd + ≤ 86.1 and 1.47 ≤ Nd + ≤ 1.65, where Vd + is the Abbe number of the at least one lens, Nd + is the refractive index of the at least one lens.

7. The imaging system of claim 3, wherein, At least one of the lenses having positive refractive power among the first cemented lens, the second cemented lens, and the third cemented lens satisfies: 59.3 ≤ Vd + ≤ 86.1 and 1.47 ≤ Nd + ≤ 1.65, wherein Vd + is the Abbe number of the at least one lens, Nd + is the refractive index of the at least one lens.

8. The imaging system of claim 1, wherein, The imaging system satisfies: 1.62 ≤ Nd L2 ≤ 1.92 and 36.4 ≤ Vd L2 ≤ 65.0, where Nd L2 is the refractive index of the second lens and Vd L2 is the Abbe number of the second lens.

9. The imaging system of claim 1, wherein, the imaging system satisfies: -0.81≤f9 / f≤-0.36, wherein f9 is the effective focal length of the ninth lens, and f is the total effective focal length of the imaging system in the intermediate state.

10. The imaging system of any of claims 1-9, wherein, the imaging system satisfies: 0.33≤Y / TTL≤0.38, wherein Y is the image height corresponding to the maximum field angle of the imaging system in the intermediate state, and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the imaging system on the optical axis when the imaging system is in the intermediate state.

11. The imaging system according to any one of claims 1-9, wherein: the object side surface of the first lens is convex, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is concave; the object side surface of the third lens is concave, and the image side surface is concave; the object side surface of the fourth lens is convex, and the image side surface is convex; the object side surface of the fifth lens is convex; the object side surface of the sixth lens is convex, and the image side surface is convex; the object side surface of the seventh lens is concave, and the image side surface is concave; the object side surface of the eighth lens is convex, and the image side surface is convex; and the object side surface of the ninth lens is concave.

12. The imaging system of any one of claims 1-9, wherein, the image side surface of the tenth lens is convex.

Images