Zoom optical system and monitoring lens
By designing the first lens group with negative power and the second lens group with positive power, combined with the aperture and aspherical lens, the existing monitoring lens has solved the problems of low pixels and small magnification, and the monitoring lens with ultra-high definition, large magnification and small zoom is achieved.
Patent Information
- Application Number
- CN202422777758.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-11-13
AI Technical Summary
The problem of existing monitoring lenses that cannot guarantee full confocal confocal per focal length during low pixels, small magnification and zooming has affected the popularity of lenses.
A zoom optical system is designed, including a first lens group, a diaphragm and a second lens group arranged in sequence along the optical axis direction. The lens group has negative and positive energy. The lens group can move along the optical axis. The field size is adjusted in combination with the diaphragm to avoid distal-axial light affecting the imaging quality. An aspherical lens and glued lens design are used to correct aberration and chromatic aberration.
It achieves ultra-high-definition, large-magnification, and small zoom effects, improves imaging quality and light transmission, and ensures consistency in imaging quality during zooming.
Smart Images
Figure CN223244886U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optics, in particular to a zoom optical system and a monitoring lens. Background Art
[0002] Currently, the zoom optical systems used for surveillance generally have the following shortcomings: low pixel count, small magnification under the same total length, and inability to ensure complete confocality of each focal length infrared during the zoom process.
[0003] Currently, there is no lens on the market that fully takes into account the above characteristics. There are only a few lenses that improve one aspect at the expense of other aspects. For example, in order to achieve ultra-high definition, the magnification is designed to be very small, and the infrared at each focal length is not guaranteed to be completely confocal, etc., which affects the popularity of the lens. Utility Model Content
[0004] The main purpose of the utility model is to propose a zoom optical system and a monitoring lens, aiming to provide a zoom optical system with ultra-high definition, large magnification and small zoom.
[0005] To achieve the above-mentioned object, the present invention provides a zoom optical system, wherein the zoom optical system has an object side and an image side disposed opposite to each other along an optical axis, and comprises a first lens group, an aperture, a second lens group, and a photosensitive chip arranged in sequence from the object side to the image side;
[0006] Wherein, the first lens group has negative optical power; the second lens group has positive optical power;
[0007] At least one of the first lens group and the second lens group is movable along the optical axis to enable the zoom optical system to perform zooming.
[0008] In one embodiment, the interval between the first lens group and the aperture is L1, the interval between the second lens group and the aperture is L2, and the intervals satisfy the following relationship: 0.8 mm ≤ L1 ≤ 8.483 mm, 0.73 mm ≤ L2 ≤ 10.594 mm.
[0009] In one embodiment, 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 along the optical axis;
[0010] The optical power of the first lens is negative, the optical power of the second lens is negative, and the optical power of the third lens is positive.
[0011] In one embodiment, the second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens, which are arranged in sequence from the object side to the image side along the optical axis;
[0012] Among them, the fourth lens has a positive optical power, the fifth lens has a negative optical power, the sixth lens has a positive optical power, the ninth lens has a positive optical power, the tenth lens has a negative optical power, and the eleventh lens has a negative optical power.
[0013] In one embodiment, 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 along the optical axis, and the second lens and the third lens are cemented together; and / or,
[0014] The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in sequence from the object side to the image side along the optical axis, the fifth lens and the sixth lens are cemented together, and the ninth lens and the tenth lens are cemented together.
[0015] In one embodiment, the fourth lens is a glass aspheric lens, and the seventh lens, the eighth lens, and the eleventh lens are plastic aspheric lenses.
[0016] In one embodiment, the eleventh lens has a mirror surface edge vignetting arrangement.
[0017] In one embodiment, the seventh lens and the eighth lens are cemented lenses.
[0018] In one embodiment, the zoom optical system further includes a filter, which is disposed between the second lens group and the photosensitive chip along the optical axis and is disposed close to the photosensitive chip.
[0019] The present invention further provides a surveillance lens, comprising a zoom optical system, wherein the zoom optical system has an object side and an image side disposed opposite to each other along an optical axis, and the zoom optical system comprises a first lens group, an aperture, a second lens group, and a photosensitive chip arranged in sequence from the object side to the image side;
[0020] wherein the first lens group has negative optical power, and the second lens group has positive optical power;
[0021] At least one of the first lens group and the second lens group is movable along the optical axis to enable the zoom optical system to perform zooming.
[0022] In the technical solution of the present invention, at least one of the first lens group and the second lens group moves along the optical axis toward the image side, and different positions of the two lens groups correspond to different overall focal lengths, so that the zoom optical system continuously changes from the wide-angle end to the telephoto end to achieve zooming; the aperture is arranged between the first lens group and the second lens group, which can adjust the field of view size, block the far-axis light, avoid the far-axis light from affecting the imaging quality, improve the image quality, and make the lens have a large light throughput; through the reasonable arrangement of the structure and position of the first lens group with negative optical focal power and the second lens group with positive optical focal power, the zoom optical system has the effects of ultra-high definition, large magnification, small zoom, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] 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.
[0024] Figure 1 This is a structural schematic diagram of an embodiment of the wide-angle end of the zoom optical system provided by the present invention.
[0025] Description of Figure Numbers:
[0026] 100. Zoom optical system; 1. First lens group; 11. First lens; 12. Second lens; 13. Third lens; 2. Second lens group; 21. Fourth lens; 22. Fifth lens; 23. Sixth lens; 24. Seventh lens; 25. Eighth lens; 26. Ninth lens; 27. Tenth lens; 28. Eleventh lens; 3. Aperture; 4. Filter; 5. Photosensitive chip.
[0027] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0029] 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 components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.
[0030] 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 implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning 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.
[0031] The present invention provides a zoom optical system 100 .
[0032] First of all, it can be understood that the optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is a positive number, the refraction of light is convergent; when the optical power is a negative number, the refraction of light is divergent. The optical power can be applied to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be applied to characterize a certain lens, and can also be applied to characterize a system formed by multiple lenses (i.e., a lens group).
[0033] See also Figure 1 In one embodiment of the present invention, the zoom optical system 100 has an object side and an image side that are oppositely arranged along the optical axis direction. The zoom optical system 100 includes a first lens group 1, an aperture 3, a second lens group 2 and a photosensitive chip 5, which are arranged in sequence from the object side to the image side; wherein, the first lens group 1 has negative optical power, and the second lens group 2 has positive optical power; at least one of the first lens group 1 and the second lens group 2 can be moved along the optical axis direction to enable the zoom optical system 100 to zoom.
[0034] In the technical solution of the present invention, at least one of the first lens group 1 and the second lens group 2 moves along the optical axis toward the image side, and different positions of the two lens groups correspond to different overall focal lengths, so that the zoom optical system 100 continuously changes from the wide-angle end to the telephoto end to achieve zooming; the aperture 3 is arranged between the first lens group 1 and the second lens group 2, which can adjust the field of view, block the far-axis light, avoid the far-axis light from affecting the imaging quality, improve the image quality, and make the lens have a large light throughput; through the reasonable arrangement of the structure and position of the first lens group 1 with negative optical focal power and the second lens group 2 with positive optical focal power, the zoom optical system 100 has the effects of ultra-high definition, large magnification, and small zoom.
[0035] Specifically, in one embodiment of the present invention, it should be understood that when the optical projection system is at the wide-angle end, the focal length is the shortest and the distance between the lens groups is the smallest. When the optical projection system is at the telephoto end, the focal length is the longest and the distance between the lens groups is also the largest. At the wide-angle end and the telephoto end, the optical projection system has different focal lengths and optical powers, and also has different lengths or shapes. When the optical projection system zooms from the wide-angle end to the telephoto end, in order to further improve the imaging effect, the first lens group 1 and the second lens group 2 are linked together, and the first lens group 1 is connected to the second lens group 2. The interval between the lens group 1 and the aperture 3 is L1, and the interval between the second lens group 2 and the aperture 3 is L2. The intervals satisfy the following relationship: 0.8mm≤L1≤8.483mm, 0.73mm≤L2≤10.594mm. By limiting the zoom distance of the first lens group 1 and the second lens group 2, the focal plane position is ensured to remain unchanged during the zooming process, thereby achieving true zoom, that is, the image quality does not change substantially from the wide-angle end to the telephoto end during the zooming process, and according to actual use needs, the zoom ratio can be achieved to 3.5 times.
[0036] Furthermore, in one embodiment of the present invention, the first lens group 1 includes a first lens 11, a second lens 12, and a third lens 13, which are arranged in sequence from the object side to the image side along the optical axis. The first lens 11 has a positive optical power and a convex object-side surface and a concave image-side surface, thereby allowing for the introduction of more light. The second lens 12 has a concave object-side surface and a concave image-side surface, while the third lens 13 has a convex object-side surface and a convex image-side surface. This arrangement ensures that the concave and convex surfaces of the second lens 12 and the third lens 13 complement each other, resulting in a more compact structure. Furthermore, the second lens 12 has a negative optical power and the third lens 13 has a positive optical power, thereby controlling the direction of light and improving resolution. By limiting the positive and negative optical powers of the first lens 11, the second lens 12, and the third lens 13 in the first lens group 1, the height of light entering the rear group is reduced, thereby reducing aberrations in the off-axis system.
[0037] In addition, in one embodiment of the present invention, the second lens group 2 includes a fourth lens 21, a fifth lens 22, a sixth lens 23, a seventh lens 24, an eighth lens 25, a ninth lens 26, a tenth lens 27, and an eleventh lens 28, which are arranged in sequence from the object side to the image side along the optical axis; wherein the fourth lens 21 has a positive optical power, the fifth lens 22 has a negative optical power, the sixth lens 23 has a positive optical power, the ninth lens 26 has a positive optical power, the tenth lens 27 has a negative optical power, and the eleventh lens 28 has a negative optical power. By limiting the positive and negative optical powers of the lenses, residual spherical aberration of the system can be corrected, and at the same time, the light height of the off-axis field of view can be increased, so that the system has a larger target surface.
[0038] In one embodiment of the present invention, 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 along the optical axis, and the second lens 12 and the third lens 13 are cemented together; the first lens group 1 uses a single lens and two spherical lenses cemented together for use, which can not only effectively correct the chromatic aberration of the zoom optical system 100, but also reduce the surface sensitivity, thereby ensuring the high resolution of the system.
[0039] In addition, in another embodiment of the utility model, the second lens group 2 includes a fourth lens 21, a fifth lens 22, a sixth lens 23, a seventh lens 24, an eighth lens 25, a ninth lens 26, a tenth lens 27, and an eleventh lens 28, which are arranged in sequence from the object side to the image side along the optical axis. The fifth lens 22 and the sixth lens 23 are cemented together, and the ninth lens 26 and the tenth lens 27 are cemented together. By arranging the fifth lens 22 and the sixth lens 23 to be cemented together, chromatic aberration is reduced while correcting light. By cementing the ninth lens 26 and the tenth lens 27 together, aberration and chromatic aberration are further reduced, thereby improving imaging quality.
[0040] Specifically, the fourth lens 21 is a glass aspheric lens, the seventh lens 24, the eighth lens 25, and the eleventh lens 28 are plastic aspheric lenses;
[0041] As can be understood, aspherical lenses are characterized by a continuously changing curvature from the lens center to the periphery. Unlike spherical lenses, which have a constant curvature from the center to the periphery, aspherical lenses have a more optimal curvature radius, improving distortion and astigmatism. Using aspherical lenses can minimize aberrations that occur during imaging, thereby improving the image quality of the lens. Furthermore, using a plastic aspherical lens as the final eleventh lens 28 can optimize and adjust the angle and direction of light entering the image plane, resulting in clearer images.
[0042] Specifically, in one embodiment of the present invention, the surface shape of the aspheric lens in the projection optical system should satisfy the following equation:
[0043]
[0044] Where c is the curvature corresponding to the radius; y is the radial coordinate (its unit is the same as the lens length unit); k is the conic coefficient, and A, B, C, D, E, F, G... represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order... aspheric coefficients, respectively.
[0045] More specifically, in one embodiment of the present invention, the even-order coefficients of each aspheric surface are shown in Table 1 below.
[0046] Table 1
[0047] k a2 a3 a4 a5 Object side of the fourth lens -1.17066 1.1509341e-004 1.1269779e-006 0 0 Side view of the fourth lens -6.282085 2.5371786e-4 -5.338235e-007 0 0 Object side of the seventh lens 37.86793 -8.6965705e-5 -8.1277096e-006 0 0 Side view of the seventh lens 300.2933 -8.0591686e-4 4.7984483e-007 0 0 Object side of the eighth lens 2.597696 -8.6150505e-004 2.4050817e-006 0 0 Side view of the eighth lens 253.6668 -8.3122613e-4 7.6248559e-007 0 0 The object side of the eleventh lens 1.430072 -3.1624826e-3 -1.455295e-005 0 0 Eleventh lens image side view 6.249964 -2.5846742e-3 1.9329853e-005 0 0
[0048] The above parameters can be used to accurately set the shape and size of the aspheric surfaces on the front and back of the lens. At the same time, the use of plastic lenses greatly reduces costs.
[0049] In one embodiment of the present invention, the eleventh lens element 28 is provided with vignetting at the edges of its mirror surface. It should be noted that vignetting refers to the phenomenon in which light entering the optical system from the edge is partially blocked due to the physical limitations of optical components (such as the lens edge, aperture 3, and lens frame). This phenomenon weakens the light intensity at the edges of the image, resulting in a vignetting effect. By providing vignetting at the edges of the mirror surface of the eleventh lens element 28, stray light from the periphery is blocked without affecting image brightness, maintaining the same resolution at the center and edges of the image.
[0050] Furthermore, in one embodiment of the present invention, the seventh lens 24 and the eighth lens 25 are quasi-cemented lenses. It should be noted that quasi-cemented refers to an optical system in which the combination and optimized design of multiple plastic lenses achieve functions and performance similar to those of traditional cemented lenses. Traditional cemented lenses achieve similar effects by gluing lenses made of different materials together. Quasi-cemented designs achieve similar effects by combining multiple plastic lenses without gluing. Compared to cemented designs, the combination of multiple plastic lenses achieves functions similar to those of traditional cemented lenses, including reducing chromatic aberration, spherical aberration, and other aberrations, while maintaining a low cost and lightweight design.
[0051] Furthermore, in one embodiment of the present invention, the first lens 11, the second lens 12, the third lens 13, the fifth lens 22, the sixth lens 23, the ninth lens 26, and the tenth lens 27 are glass spherical lenses. To improve the imaging quality of the lens at various magnifications, the present invention combines high-refractive-index glass with ultra-low-dispersion glass materials to reduce various optical aberrations while effectively suppressing chromatic aberration of the system. Furthermore, because glass lenses are less susceptible to thermal expansion and contraction, resulting in focus shift, they are well resistant to thermal deformation and maintain high lens precision over a long period of time. Furthermore, aberrations that occur during imaging are minimized, achieving a positive and negative balance of the varying values of various elements at high and low temperatures, ensuring synchronization and clarity of the image plane at both high and low temperatures, thereby improving the lens's imaging quality and minimizing the impact of temperature on the system's optical performance.
[0052] Specifically, in an embodiment of the present invention, the parameters of the zoom optical system 100 are shown in Table 2 below.
[0053] Table 2
[0054]
[0055]
[0056] In one embodiment of the present invention, the zoom optical system 100 also includes a filter 4, which is arranged between the second lens group 2 and the photosensitive chip 5 along the optical axis and is arranged close to the photosensitive chip 5. By setting the filter 4, the filter 4 can filter out stray light and prevent stray light from reaching the photosensitive chip 5 and interfering with normal visible light imaging, thereby improving imaging quality.
[0057] It can be understood that the light carrying the information of the subject can pass through the first lens 11, the second lens 12, the third lens 13, the aperture 3, the fourth lens 21, the fifth lens 22, the sixth lens 23, the seventh lens 24, the eighth lens 25, the ninth lens 26, the tenth lens 27, the eleventh lens 28, the filter 4 in sequence and finally form an image on the photosensitive chip 5.
[0058] The present invention also provides a monitoring lens, which includes a zoom optical system. The specific structure of the zoom optical system refers to the above-mentioned embodiment. Since the monitoring lens adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.
[0059] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical 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. A zoom optical system, characterized in that: The zoom optical system has an object side and an image side that are opposite to each other along the optical axis, and includes a first lens group, an aperture, a second lens group, and a photosensitive chip that are arranged in sequence from the object side to the image side; wherein the first lens group has negative optical power, and the second lens group has positive optical power; At least one of the first lens group and the second lens group is movable along the optical axis to enable the zoom optical system to zoom; The interval between the first lens group and the aperture is L1, the interval between the second lens group and the aperture is L2, and the intervals satisfy the following relationship: 0.8 mm ≤ L1 ≤ 8.483 mm, 0.73 mm ≤ L2 ≤ 10.594 mm.
2. The zoom optical system according to claim 1, wherein: 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 along the optical axis; The optical power of the first lens is negative, the optical power of the second lens is negative, and the optical power of the third lens is positive.
3. The zoom optical system according to claim 1, wherein: The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens, which are arranged in sequence from the object side to the image side along the optical axis; Among them, the fourth lens has a positive optical power, the fifth lens has a negative optical power, the sixth lens has a positive optical power, the ninth lens has a positive optical power, the tenth lens has a negative optical power, and the eleventh lens has a negative optical power.
4. The zoom optical system according to claim 1, wherein: 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 along the optical axis, and the second lens and the third lens are cemented together; and / or, The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in sequence from the object side to the image side along the optical axis, the fifth lens and the sixth lens are cemented together, and the ninth lens and the tenth lens are cemented together.
5. The zoom optical system according to claim 4, wherein: The fourth lens is a glass aspheric lens, and the seventh lens, the eighth lens, and the eleventh lens are plastic aspheric lenses.
6. The zoom optical system according to claim 5, wherein: The edge of the mirror surface of the eleventh lens is vignetted.
7. The zoom optical system according to claim 5, wherein: The seventh lens and the eighth lens are cemented lenses.
8. The zoom optical system according to claim 1, wherein: The zoom optical system also includes a filter, which is arranged between the second lens group and the photosensitive chip along the optical axis and is arranged close to the photosensitive chip.
9. A surveillance camera, characterized in that: Comprising the zoom optical system according to any one of claims 1 to 8.