Optical system and monitoring device

Abstract

The present invention discloses an optical system and a monitoring device, wherein the optical system includes a plurality of lens groups arranged sequentially from the object side to the image side, with an optical axis formed between the plurality of lens groups. The plurality of lens groups include a first lens group, a second lens group, and a third lens group. The first lens group has negative optical power and is movable along the extension direction of the optical axis, and includes first to third lenses. The second lens group has positive optical power and is movable along the extension direction of the optical axis, and includes fourth to tenth lenses. The third lens group has positive or negative optical power and includes an eleventh lens. The first, sixth, eighth, and ninth lenses are glass spherical lenses, the second, third, fifth, seventh, tenth, and eleventh lenses are plastic aspherical lenses, and the fourth lens is a glass aspherical lens. The present invention aims to improve the imaging effect of the optical system.

Description

Technical Field

[0001] The present invention relates to the technical field of optical equipment, and in particular to an optical system and a monitoring device. Background Art

[0002] Current surveillance zoom optical systems suffer from common shortcomings: low system resolution, black-and-white infrared mode, high cost, and the inability to guarantee complete parfocality at every focal length during zooming. Currently, no lens on the market fully addresses these characteristics. A few improve one aspect at the expense of others. For example, achieving full-color infrared mode requires the use of multiple glass spherical and aspherical lenses. This results in high costs and little resolution improvement, hindering widespread adoption. Summary of the Invention

[0003] The main purpose of the present invention is to provide an optical system and a monitoring device, aiming to improve the imaging effect of the optical system.

[0004] To achieve the above object, the present invention provides an optical system, wherein the optical system includes a plurality of lens groups arranged sequentially from the object side to the image side, wherein the plurality of lens groups form an optical axis, wherein the plurality of lens groups include:

[0005] a first lens group having negative optical power and being movable along the extension direction of the optical axis, the first lens group comprising a first lens, a second lens, and a third lens arranged in sequence from the object side to the image side;

[0006] a second lens group having positive refractive power and movable along the extension direction of the optical axis, the second lens group comprising a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens arranged in sequence from the object side to the image side; and

[0007] a third lens group having positive or negative refractive power and including an eleventh lens;

[0008] Among them, the first lens, the sixth lens, the eighth lens and the ninth lens are glass spherical lenses, the second lens, the third lens, the fifth lens, the seventh lens, the tenth lens and the eleventh lens are plastic aspherical lenses, and the fourth lens is a glass aspherical lens.

[0009] Optionally, the interval between the first lens group and the aperture is a, and 0.883 mm ≤ a ≤ 13.055 mm; and / or,

[0010] The interval between the aperture and the second lens group is b, and -0.08 mm ≤ b ≤ 7.62 mm.

[0011] Optionally, the fourth lens in the second lens group has positive optical power, the fifth lens has positive or negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, the ninth lens has negative optical power, and the tenth lens has positive optical power.

[0012] Optionally, the second lens is cemented to the third lens.

[0013] Optionally, the eighth lens and the ninth lens are bonded together using optical glue.

[0014] Optionally, each lens has an object-side surface and an image-side surface,

[0015] The object-side surface of the first lens is a convex surface convex toward the object, and the image-side surface is a concave surface convex toward the object;

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

[0017] The object side surface of the third lens is a convex surface convex toward the object side, and the image side surface thereof is a convex surface convex toward the image side;

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

[0019] The object side surface of the fifth lens is a convex surface convex toward the object side, and the image side surface is a concave surface convex toward the object side;

[0020] The object side surface of the sixth lens is a convex surface convex toward the object side, and the image side surface thereof is a convex surface convex toward the image side;

[0021] The object side surface of the seventh lens is a concave surface convex toward the image side, and the image side surface is a concave surface convex toward the object side;

[0022] The object side surface of the eighth lens is a convex surface convex toward the object side, and the image side surface thereof is a convex surface convex toward the image side;

[0023] The object side surface of the ninth lens is a concave surface convex toward the image side, and the image side surface is a concave surface convex toward the object side;

[0024] The object side surface of the tenth lens is a convex surface convex toward the object side, and the image side surface is a concave surface convex toward the object side;

[0025] The object side surface of the eleventh lens is a concave surface convex toward the image side, and the image side surface is a convex surface convex toward the image side.

[0026] The present invention also proposes a monitoring device, wherein the monitoring device includes the optical system, the optical system includes a plurality of lens groups arranged in sequence from the object side to the image side, and an optical axis is formed correspondingly between the plurality of lens groups, wherein the plurality of lens groups include a first lens group, a second lens group and a third lens group, the first lens group has a negative optical focal length and can be movably set along the extension direction of the optical axis, the first lens group includes a first lens, a second lens and a third lens arranged in sequence from the object side to the image side; the second lens group has a positive optical focal length and can be movably set along the extension direction of the optical axis, the second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens arranged in sequence from the object side to the image side; the third lens group has a positive optical focal length or a negative optical focal length and includes an eleventh lens; wherein the first lens, the sixth lens, the eighth lens and the ninth lens are glass spherical lenses, the second lens, the third lens, the fifth lens, the seventh lens, the tenth lens and the eleventh lens are plastic aspherical lenses, and the fourth lens is a glass aspherical lens.

[0027] In the technical solution of the present invention, to achieve complete infrared confocality, multiple lens groups are used to ensure that the refractive index and Abbe number of light from the object side to the image side complement each other, ensuring minimal chromatic aberration in the visible band while also maintaining resolution in the infrared band, achieving a perfect match of lens materials. Furthermore, to achieve ultra-high resolution, control purple fringing, and full-power infrared confocality, the positions of the first and second lens groups are adjusted so that the change in the conjugate distance of the first lens group and the change in the conjugate distance after magnification of the second lens group offset each other, achieving image plane compensation. Furthermore, the technical solution of this application rationally considers lens layout, particularly the combination of plastic and glass lenses, significantly reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0029] Figure 1 A simplified structural diagram of an embodiment of the optical system provided by the present invention.

[0030] Description of Figure Numbers:

[0031]

[0032]

[0033] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] Current surveillance zoom optical systems suffer from common shortcomings: low system resolution, black-and-white infrared mode, high cost, and the inability to guarantee complete parfocality at every focal length during zooming. Currently, no lens on the market fully addresses these characteristics. A few improve one aspect at the expense of others. For example, achieving full-color infrared mode requires the use of multiple glass spherical and aspherical lenses. This results in high costs and little resolution improvement, hindering widespread adoption.

[0038] In view of this, the present invention provides an optical system, Figure 1 The embodiments of the optical system provided by the present invention will be described below with reference to specific drawings.

[0039] See also Figure 1 The optical system 100 includes a plurality of lens groups arranged in sequence from the object side to the image side, and an optical axis 4 is formed between the plurality of lens groups. The plurality of lens groups include a first lens group 1, a second lens group 2, and a third lens group 3. The first lens group 1 has negative optical power and can be movably arranged along the extension direction of the optical axis 4. The first lens group 1 includes a first lens 11, a second lens 12, and a third lens 13 arranged in sequence from the object side to the image side; the second lens group 2 has positive optical power and can be movably arranged along the extension direction of the optical axis 4. The second lens group 2 includes a first lens 11, a second lens 12, and a third lens 13 arranged in sequence from the object side to the image side. The fourth lens 21, the fifth lens 22, the sixth lens 23, the seventh lens 24, the eighth lens 25, the ninth lens 26 and the tenth lens 27 are provided. The third lens group 3 has positive or negative optical power and includes an eleventh lens 31. The first lens 11, the sixth lens 23, the eighth lens 25 and the ninth lens 26 are glass spherical lenses, the second lens 12, the third lens 13, the fifth lens 22, the seventh lens 24, the tenth lens 27 and the eleventh lens 31 are plastic aspherical lenses, and the fourth lens 21 is a glass aspherical lens.

[0040] In the technical solution of the present invention, in order to achieve complete infrared confocality, multiple lens groups are used to ensure that the refractive index and Abbe number of light from the object side to the image side are complementary, ensuring the resolution effect in the infrared band while ensuring small chromatic aberration in the visible band, and realizing a perfect match of lens materials. At the same time, in order to achieve ultra-high resolution, control of purple fringing and full-power confocality in the infrared, the positions of the first lens group 1 and the second lens group 2 are adjusted so that the change in the conjugate distance of the first lens group 1 and the change in the conjugate distance after magnification of the second lens group 2 are offset to achieve image plane compensation. In addition, the technical solution of the present application reasonably considers the lens layout, especially the combination of plastic and glass lenses, which greatly controls costs. Specifically, the third lens group 3 in this embodiment uses positive focal length.

[0041] Specifically, an aperture 5 is provided between the first lens group 1 and the second lens group 2, which is beneficial for blocking part of the light during the zooming process and improving the imaging quality.

[0042] Furthermore, the spacing between the first lens group 1 and the aperture 5 is a, and 0.883mm≤a≤13.055mm; and / or the spacing between the aperture 5 and the second lens group 2 is b, and -0.08mm≤b≤7.62mm. In this embodiment, the spacing between the first lens group 1 and the aperture 5 is set between 0.883mm and 13.055mm, and the spacing between the second lens group 2 and the aperture 5 is set between -0.08mm and 7.62mm.

[0043] In addition, the optical system 100 further includes a photosensitive chip 7, which is disposed on the image side of the third lens group 3, with the photosensitive surface of the photosensitive chip 7 facing the third lens group 3, so as to receive an object image on the image side of the optical system 100.

[0044] Furthermore, a filter 6 is provided between the photosensitive chip 7 and the third lens group 3 to adjust the color of the final image.

[0045] In addition, the first lens 11 in the first lens group 1 is independently arranged, and the second lens 12 and the third lens 13 are in contact with each other to form a quasi-cemented structure, thereby eliminating glue and bonding time and achieving the effect of bonding lenses. In this way, not only can the chromatic aberration of the lens be corrected well to ensure infrared confocality, but also the spherical aberration and sine difference at high magnification positions can be corrected.

[0046] Furthermore, the fourth lens 21 in the second lens group 2 uses a high Abbe number glass aspherical lens, which can reduce the deflection angle of marginal light, make the lens smaller and more compact, and thus achieve a larger magnification. The fifth lens 22, the sixth lens 23, the seventh lens 24 and the eighth lens 25 abut against each other to form the above-mentioned quasi-glued structure. The eighth lens 25 and the ninth lens 26 are bonded with optical glue. The ninth lens 26 and the tenth lens 27 are also abutted to form a quasi-glued structure, so that the plastic aspherical lens and the glass spherical lens abut against each other to form a quasi-glued structure, and the two glass spherical lenses are bonded with optical glue.

[0047] In addition, the fourth lens 21 in the second lens group 2 has positive focal power, the fifth lens 22 has positive or negative focal power, the sixth lens 23 has positive focal power, the seventh lens 24 has negative focal power, the eighth lens 25 has positive focal power, the ninth lens 26 has negative focal power, and the tenth lens 27 has positive focal power. Specifically, in this embodiment, the fifth lens 22 has negative focal power, so that the second lens group 2 forms a lens combination of positive, negative, positive, negative, positive, negative, and positive to form a chromatic aberration-eliminating structure, achieve high-order aberration correction and ensure chromatic aberration correction; not only eliminates the chromatic aberration of the entire system, but also well balances the aberration of the entire system, achieving chromatic aberration correction.

[0048] Furthermore, the third lens group 3 is a plastic lens that corrects aberrations of light reaching the image plane. This ensures the clarity of the entire system, achieving ultra-high-definition resolution and full parfocality at all magnifications in infrared. Finally, a certain degree of vignetting is added to block peripheral stray light without affecting image illumination, achieving high resolution at the center of the image plane while also achieving very high resolution at the edges.

[0049] Specifically, in order to achieve high and low temperature confocality of the system, the design of this application fully considers the changes in the refractive index and Abbe number of various lens materials at high and low temperatures, and at the same time matches the changes in surface shape and air spacing to achieve the matching of various high and low temperature elements, thereby achieving synchronization and clarity of the image surface at high and low temperatures.

[0050] Specifically, please refer to Tables 1 and 2 below, wherein Tables 1 and 2 provide specific data of an embodiment of the optical system 100 proposed in this application.

[0051] As shown in Table 1, it specifically includes the surface number, surface type, radius, thickness, material and effective diameter; the positive and negative signs of the radius meet the basic sign rules of optics.

[0052] As shown in Table 2, these are the conic quadratic curve coefficients and aspheric coefficients corresponding to the two surfaces of the aspheric lens in Table 1.

[0053] Table 1

[0054]

[0055]

[0056] Table 2

[0057]

[0058] The surface shape of each aspheric surface should satisfy the following equation:

[0059]

[0060] Where c is the curvature corresponding to the radius; y is the radial coordinate (its units are the same as the lens length); k is the conic coefficient, and a1, a2, a3, a4, a5, a6, a7, and a8 are the coefficients corresponding to the radial coordinates. These parameters can be used to set the shape and dimensions of the lens's aspheric surface facing the projection plane and light source.

[0061] Among them, when k is less than -1, the corresponding surface curve of the lens is a hyperbola; when k is equal to -1, the corresponding surface curve of the lens is a parabola; when -1 is less than k and less than 0, the corresponding surface curve of the lens is an ellipse; when k is equal to 0, the corresponding surface curve of the lens is a circle; when k is greater than 0, the corresponding surface curve of the lens is an oblate circle.

[0062] The surface numbers are the surfaces of each lens from the object side to the image side. For example, S1 is a surface of the first lens 11 close to the object side, and S2 is a surface of the first lens 11 close to the image side.

[0063] Specifically, each lens has an object side surface and an image side surface. The object side surface of the first lens 11 is a convex surface convex toward the object, and the image side surface is a concave surface convex toward the object; the object side surface of the second lens 12 is a concave surface convex toward the image, and the image side surface is a concave surface convex toward the object; the object side surface of the third lens 13 is a convex surface convex toward the object, and the image side surface is a convex surface convex toward the image; the object side surface of the fourth lens 21 is a convex surface convex toward the object, and the image side surface is a convex surface convex toward the image; the object side surface of the fifth lens 22 is a convex surface convex toward the object, and the image side surface is a concave surface convex toward the object; the sixth lens 2 The object side surface of the seventh lens element 24 is a convex surface convex toward the image side, and the image side surface is a convex surface convex toward the object side; the object side surface of the eighth lens element 25 is a convex surface convex toward the object side, and the image side surface is a convex surface convex toward the image side; the object side surface of the ninth lens element 26 is a concave surface convex toward the image side, and the image side surface is a concave surface convex toward the object side; the object side surface of the tenth lens element 27 is a convex surface convex toward the object side, and the image side surface is a concave surface convex toward the object side; the object side surface of the eleventh lens element 31 is a concave surface convex toward the image side, and the image side surface is a convex surface convex toward the image side.

[0064] In summary, the optical system 100 proposed in the present application achieves complete confocality in the visible band and the infrared band, ensuring the imaging clarity of the visible band and the infrared band during the 3.45-11mm zoom process; most of the zoom lenses on the market will appear out of focus or blurred at high temperatures of 70°C or low temperatures of -30°C when in focus at room temperature of 20°C; the optical system 100 proposed in the present application ensures complete confocality at all magnifications and high and low temperatures; most of such small zoom lenses on the market have a W-end FNO greater than 1.35, and the W-end FNO of the optical system 100 proposed in the present application reaches 1.0, so that in low-light environments, the image plane has sufficient brightness, ensuring the clarity of the entire picture and full-color effects; most of such small zoom lenses on the market can only match 5MP chips, and the optical system 100 proposed in the present application has taken good consideration of the material matching and fully corrected the various aberrations of the lens, which can meet the use requirements of 4K chips and ensure high clarity of the image plane.

[0065] The present invention further provides a monitoring device, comprising the optical system 100. The specific structure of the optical system 100 is described in the aforementioned embodiments. Because the monitoring device utilizes all of the technical solutions of all of the aforementioned embodiments, it possesses at least all of the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and thus will not be further detailed here.

[0066] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An optical system, characterized in that: The optical system includes a plurality of lens groups arranged sequentially from the object side to the image side, wherein an optical axis is formed between the plurality of lens groups, wherein the plurality of lens groups include: a first lens group having negative optical power and being movable along the extension direction of the optical axis, the first lens group comprising a first lens, a second lens, and a third lens arranged in sequence from the object side to the image side; a second lens group having positive refractive power and movable along the extension direction of the optical axis, the second lens group comprising a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens arranged in sequence from the object side to the image side; and a third lens group having positive or negative refractive power and including an eleventh lens; The first lens, the sixth lens, the eighth lens, and the ninth lens are made of glass spherical lenses, the second lens, the third lens, the fifth lens, the seventh lens, the tenth lens, and the eleventh lens are made of plastic aspherical lenses, and the fourth lens is made of glass aspherical lenses. The second lens abuts against the third lens; The eighth lens and the ninth lens are bonded together by optical glue.

2. The optical system according to claim 1, wherein A stop is provided between the first lens group and the second lens group; The interval between the first lens group and the aperture is a, and 0.883 mm ≤ a ≤ 13.055 mm; and / or, The interval between the aperture and the second lens group is b, and -0.08 mm ≤ b ≤ 7.62 mm.

3. The optical system according to claim 1, wherein The fourth lens has positive optical power, the fifth lens has positive or negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, the ninth lens has negative optical power, and the tenth lens has positive optical power.

4. The optical system according to claim 1, wherein Each lens has an object side surface and an image side surface. The object-side surface of the first lens is a convex surface convex toward the object, and the image-side surface is a concave surface convex toward the object; The object side surface of the second lens is a concave surface convex toward the image side, and the image side surface is a concave surface convex toward the object side; The object side surface of the third lens is a convex surface convex toward the object side, and the image side surface thereof is a convex surface convex toward the image side; The object side surface of the fourth lens is a convex surface convex toward the object side, and the image side surface is a convex surface convex toward the image side; The object side surface of the fifth lens is a convex surface convex toward the object side, and the image side surface is a concave surface convex toward the object side; The object side surface of the sixth lens is a convex surface convex toward the object side, and the image side surface thereof is a convex surface convex toward the image side; The object side surface of the seventh lens is a concave surface convex toward the image side, and the image side surface is a concave surface convex toward the object side; The object side surface of the eighth lens is a convex surface convex toward the object side, and the image side surface thereof is a convex surface convex toward the image side; The object side surface of the ninth lens is a concave surface convex toward the image side, and the image side surface is a concave surface convex toward the object side; The object side surface of the tenth lens is a convex surface convex toward the object side, and the image side surface is a concave surface convex toward the object side; The object side surface of the eleventh lens is a concave surface convex toward the image side, and the image side surface is a convex surface convex toward the image side.

5. A monitoring device, characterized in that: Comprising the optical system according to any one of claims 1 to 4.

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