imaging device

Abstract

The application discloses an imaging device, which comprises a zoom system, the zoom system comprising a lens barrel and sequentially arranged from an object side to an image side a first lens group, a second lens group, a third lens group, a fourth lens group and a fifth lens group, the image surface size being set as φ7.7mm, the zoom system wide-angle end focal length being 5.59mm, the zoom system telephoto end focal length being 151.10mm, the zoom system wide-angle end aperture number being 1.66, the zoom system telephoto end aperture number being 4.97, the optical distortion range being controlled between-4% and 4%, and the total optical length TTL of the zoom system being only 92mm, so that the imaging device can work stably in the day and night and in the environment with large temperature difference, and has high imaging quality, small size, high magnification and wide application environment.

Description

Technical Field

[0001] This invention relates to the field of optical system design technology, and in particular to an imaging device. Background Technology

[0002] With the rapid development of the security monitoring industry, zoom lenses are playing an increasingly important role. Currently, mainstream zoom lenses with higher magnification often come with larger sizes, limiting the development of zoom systems towards higher magnification and miniaturization. Therefore, developing a high-magnification, miniaturized lens is key to solving this problem. Summary of the Invention

[0003] The main objective of this invention is to provide an imaging device that offers high imaging quality, small size, high magnification, and wide applicability.

[0004] To achieve the above objectives, the present invention provides an imaging device, the imaging device including a zoom system having an object side and an image side arranged opposite to each other along the optical axis, the zoom system including a lens barrel and a plurality of lens groups disposed within the lens barrel, the plurality of lens groups including:

[0005] The first lens group is fixed inside the lens barrel, and the optical power of the first lens group is positive.

[0006] The second lens group is movably disposed along the extension direction of the optical axis. The second lens group is used to zoom the zoom system from the wide-angle end to the telephoto end when it moves toward the image side. The optical power of the second lens group is negative.

[0007] A third lens group is movably disposed along the extension direction of the optical axis, and the optical power of the third lens group is positive; and,

[0008] A fourth lens group is movably disposed along the extension direction of the optical axis so as to enable the zoom system to focus when moving along the optical axis direction, wherein the optical power of the fourth lens group is positive;

[0009] The fifth lens group is fixed inside the lens barrel, and the optical power of the fifth lens group is positive;

[0010] Wherein, the focal length of the zoom system at the wide-angle end is fw, the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, the focal length of the fourth lens group is f4, and the focal length of the fifth lens group is f5. The zoom system satisfies the following conditions:

[0011] 0.119 < fw / f1 < 0.178, and -0.906 < fw / f2 < -0.604, and 0.171 < fw / f3 < 0.257, and 0.231 < fw / f4 < 0.346, and 0.011 < fw / f5 < 0.016.

[0012] Optionally, the first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged in sequence from the object side to the image side;

[0013] The second lens group includes a fifth lens, a sixth lens, and a seventh lens arranged in sequence from the object side to the image side;

[0014] The third lens group includes an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens arranged in sequence from the object side to the image side;

[0015] The fourth lens group includes a thirteenth lens, a fourteenth lens, and a fifteenth lens arranged in sequence from the object side to the image side;

[0016] The fifth lens group includes a sixteenth lens.

[0017] Optionally, the first lens has a negative focal power, the second lens has a positive focal power, the third lens has a positive focal power, and the fourth lens has a positive focal power;

[0018] The first lens and the second lens are adhesively connected;

[0019] The focal length of the first lens is f11, the focal length of the second lens is f12, the focal length of the third lens is f13, the focal length of the fourth lens is f14, and the lenses within the first lens group satisfy the following conditions:

[0020] -0.545 < f1 / f11 < -0.364, and 0.440 < f1 / f12 <​​​​​​​​​

[0024] Optionally, the eighth lens has a positive optical power, the ninth lens has a positive optical power, the tenth lens has a positive optical power, the eleventh lens has a negative optical power, and the twelfth lens has a positive optical power;

[0025] The tenth lens and the eleventh lens are cemented together;

[0026] The focal length of the eighth lens is f31, the focal length of the ninth lens is f32, the focal length of the tenth lens is f33, the focal length of the eleventh lens is f34, and the focal length of the twelfth lens is f35. The lenses in the third lens group satisfy the following conditions:

[0027] 0.733 < f3 / f31 < 1.100, and 1.009 < f3 / f32 < 1.514, and 0.345 < f3 / f33 < 0.517, and -3.340 < f3 / f34 < -2.226, and 0.561 < f3 / f35 < 0.842.

[0028] Optionally, the thirteenth lens has a positive optical power, the fourteenth lens has a positive optical power, and the fifteenth lens has a negative optical power;

[0029] The fourteenth lens and the fifteenth lens are cemented together;

[0030] The focal length of the thirteenth lens is f41, the focal length of the fourteenth lens is f42, and the focal length of the fifteenth lens is f43. The lenses in the fourth lens group satisfy the following conditions:

[0031] 0.225 < f4 / f41 < 0.337, and 0.998 < f4 / f42 < 1.497, and -0.567 < f4 / f43 < -0.378.

[0032] Optionally, the sixteenth lens has a positive optical power.

[0033] Optionally, the first lens, the second lens, the third lens, and the fourth lens are all glass spherical lenses;

[0034] The fifth lens and the sixth lens are both glass aspherical lenses, and the seventh lens is a glass spherical lens;

[0035] The eighth lens is a glass aspherical lens, the ninth lens, the tenth lens, and the eleventh lens are glass spherical lenses, and the twelfth lens is a glass aspherical lens;

[0036] The thirteenth lens, the fourteenth lens, and the fifteenth lens are glass spherical lenses;

[0037] The sixteenth lens is a plastic aspherical lens.

[0038] Optionally, the zoom system satisfies the following conditions:

[0039] in, The effective aperture of the first lens is denoted by , and TTL is the total optical length of the zoom system.

[0040] Optionally, the zoom system satisfies the following condition: -0.301 < ΔZ1 W-T / TTL<-0.231, and 0.096<ΔZ2 W-T / TTL<0.125;

[0041] Wherein, ΔZ1 W-T ΔZ2 represents the relative displacement of the fifth lens when the zoom system is in the wide-angle position and when it is in the telephoto position. W-T The eighth lens represents the relative displacement between the zoom system when it is in the wide-angle position and when it is in the telephoto position, and TTL represents the total optical length of the zoom system.

[0042] In the technical solution provided by this invention, the second lens group, the third lens group, and the fourth lens group are movably mounted on the lens barrel along the optical axis. The second and third lens groups are used for zooming, and the fourth lens group moves in coordination along the optical axis to perform moving focus corresponding to the position, imaging wavelength, and imaging object distance of the second and third lens groups. This ensures that the zoom system maintains sharp image on the image plane during zooming. The image plane size is set to φ7.7mm. This is achieved through the reasonable arrangement of the five lens groups. Despite the conditional limitations on the focal length ratio of the wide-angle end of the zoom system and the focal length ratio of each lens group, a focal length (fw) of 5.59mm is achieved at the wide-angle end and a focal length (ft) of 151.10mm at the telephoto end; the aperture number reaches 1.66 at the wide-angle end and 4.97 at the telephoto end; the optical distortion range is controlled between -4% and 4%; and the total optical length (TTL) of the zoom system is only 92mm. It can also work stably in day and night, and in environments with large temperature differences, thus providing an imaging device with high image quality, small size, high magnification, and wide application range. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the first embodiment of the zoom system provided by the present invention when it is at the wide-angle end;

[0045] Figure 2 This is a schematic diagram of the zoom system at an intermediate magnification.

[0046] Figure 3 This is a schematic diagram of the zoom system when it is at the telephoto end.

[0047] Figure 4 for Figure 1 Aberration diagram of the zoom system at the wide-angle end;

[0048] Figure 5 for Figure 1 Field curvature / distortion diagram of the zoom system at the wide-angle end;

[0049] Figure 6 for Figure 2 Spherical aberration map of the zoom system at intermediate magnification;

[0050] Figure 7 for Figure 2 Field curvature / distortion diagram of the zoom system at intermediate magnification;

[0051] Figure 8 for Figure 3 Aberration diagram of the zoom system at the telephoto end;

[0052] Figure 9 for Figure 3 Field curvature / distortion diagram of the zoom system at the telephoto end.

[0053] Explanation of icon numbers:

[0054]

[0055]

[0056] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0058] It should be noted that if the embodiments of the present invention involve directional indication, the directional indication is only used to explain the relative positional relationship and movement of the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0059] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Moreover, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0060] The security monitoring industry has also experienced rapid development, and zoom monitoring lenses are playing an increasingly important role. Currently, mainstream zoom monitoring lenses with higher magnification often come with larger sizes, limiting the development of zoom systems towards higher magnification and miniaturization. Therefore, developing a high-magnification, miniaturized lens is key to solving this problem.

[0061] This invention provides an imaging device, which can be configured as a monitoring device, camera, etc. It aims to provide an imaging device with high imaging quality, high magnification, miniaturization, and wide applicability. Please refer to [reference needed]. Figures 1 to 9 The attached figure shows a specific embodiment of the imaging device.

[0062] Figures 1 to 9 This is an embodiment of the imaging device provided by the present invention.

[0063] Please refer to Figures 1 to 3, the imaging device includes a zoom system, the zoom system having an object side and an image side disposed opposite to each other along the optical axis direction. The zoom system includes a lens barrel (not shown in the figure) and a plurality of lens groups. The lens barrel extends along the optical axis direction, and the lens groups are disposed inside the lens barrel. The plurality of lens groups includes a first lens group 1, a second lens group 2, a third lens group 3, a fourth lens group 4, and a fifth lens group 5 arranged in sequence from the object side to the image side. The first lens group 1 is fixedly disposed inside the lens barrel, and the optical power of the first lens group 1 is positive; the second lens group 2 is movably disposed along the extension direction of the optical axis, and the second lens group 2 is used to zoom the zoom system from the wide-angle end to the telephoto end when moving toward the image side, and the optical power of the second lens group 2 is negative; the third lens group 3 is movably disposed along the extension direction of the optical axis, and the optical power of the third lens group 3 is positive; the fourth lens group 4 is movably disposed along the extension direction of the optical axis to focus the zoom system when moving along the optical axis direction, and the optical power of the fourth lens group 4 is positive; the fifth lens group 5 is fixedly disposed inside the lens barrel, and the optical power of the fifth lens group 5 is positive; wherein, the focal length of the zoom system at the wide-angle end is fw, the focal length of the first lens group 1 is f1, the focal length of the second lens group 2 is f2, the focal length of the third lens group 3 is f3, the focal length of the fourth lens group 4 is f4, and the focal length of the fifth lens group 5 is f5. The zoom system satisfies the following conditions:

[0064] 0.119 < fw / f1 < 0.178, and -0.906 < fw / f2 < -0.604, and 0.171 < fw / f3 < 0.257, and 0.231 < fw / f4 < 0.346, and 0.011 < fw / f5 < 0.016.

[0065] It should be noted that the second lens group 2 and the third lens group 3 are used for zooming when moving along the extension direction of the optical axis. The fourth lens group 4 is driven by an external force to move along the optical axis in correspondence with the positions of the second lens group 2 and the third lens group 3, the imaging wavelength, and the imaging object distance for focusing, so that the zoom system maintains a clear image formation on the image plane 6 during the zooming process.

[0066] It should also be noted that the second lens group 2, the third lens group 3, and the fourth lens group 4 can all be driven by an external force to move along the optical axis direction. Among them, the external force drive can be a drive motor drive or manual adjustment by a human, which is not limited here.

[0067] In the technical solution provided by this invention, the second lens group 2, the third lens group 3, and the fourth lens group 4 are movably mounted on the lens barrel along the optical axis. The second lens group 2 and the third lens group 3 are used for zooming, and the fourth lens group 4 moves in coordination along the optical axis to perform moving focus corresponding to the position, imaging wavelength, and imaging object distance of the second lens group 2 and the third lens group 3, so that the zoom system keeps the image plane 6 in sharp focus during the zooming process. The size of the image plane 6 is set to φ7.7mm, and the five lens groups are used for zooming. By rationally setting up the zoom system and conditionally limiting the focal length ratio of each lens group at the wide-angle end, a focal length (fw) of 5.59mm is achieved at the wide-angle end and a focal length (ft) of 151.10mm at the telephoto end; the aperture number at the wide-angle end reaches 1.66, and the aperture number at the telephoto end reaches 4.97. The optical distortion range is controlled between -4% and 4%, and the total optical length (TTL) of the zoom system is only 92mm. It can work stably in both day and night, and in environments with large temperature differences, thus providing an imaging device with high imaging quality, small size, high magnification, and wide application environment.

[0068] In one specific embodiment, the ratio of the focal length of the zoom system at the wide-angle end to the focal length of each lens group is as follows:

[0069] fw / f1 = 0.142; fw / f2 = -0.724; fw / f3 = 0.206; fw / f4 = 0.277; and fw / f5 = 0.013.

[0070] Specifically, in this embodiment, the first lens group 1 includes a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 arranged in sequence from the object side to the image side; the second lens group 2 includes a fifth lens 21, a sixth lens 22, and a seventh lens 23 arranged in sequence from the object side to the image side; the third lens group 3 includes an eighth lens 31, a ninth lens 32, a tenth lens 33, an eleventh lens 34, and a twelfth lens 35 arranged in sequence from the object side to the image side; the fourth lens group 4 includes a thirteenth lens 41, a fourteenth lens 42, and a fifteenth lens 43 arranged in sequence from the object side to the image side; the fifth lens group 5 includes a sixteenth lens 51. Thus, by specifically setting the above sixteen lenses, the technical parameters achievable by the present invention can be reached. Of course, it can be understood that the first lens group 1, the second lens group 2, the third lens group 3, the fourth lens group 4, and the fifth lens group 5 may also include other combination forms. Each lens group is restricted by comprehensive constraints such as the number, material, refractive index, and focal length of the lenses. Ultimately, the combination forms within the range of 0.119 < fw / f1 < 0.178, -0.906 < fw / f2 < -0.604, 0.171 < fw / f3 < 0.257, 0.231 < fw / f4 < 0.346, and 0.011 < fw / f5 < 0.016 of the zoom system in the imaging device are within the protection scope of this application.

[0071] Specifically, the first lens 11 has a negative optical power, the second lens 12 has a positive optical power, the third lens 13 has a positive optical power, and the fourth lens 14 has a positive optical power; the focal length of the first lens 11 is f11, the focal length of the second lens 12 is f12, the focal length of the third lens 13 is f13, and the focal length of the fourth lens 14 is f14. The lenses within the first lens group 1 satisfy the following conditions:

[0072] -0.545 < f1 / f11 < -0.364, and 0.44 < f1 / f12 < 0.66, and 0.42 < f1 / f13 < 0.63, and 0.354 < f1 / f14 < 0.531.

[0073] More specifically, in this embodiment, the first lens 11 is a convex-concave spherical lens with a negative optical power, that is, the object side of the first lens 11 is convex and the image side is concave. The second lens 12 is a biconvex spherical lens with a positive optical power. The third lens 13 is a convex-concave spherical lens with a positive optical power, that is, the object side of the third lens 13 is convex and the image side is concave. The fourth lens 14 is a convex-concave spherical lens with a positive optical power, that is, the object side of the fourth lens 14 is convex and the image side is concave. The focal length ratios of the first lens group 1 to each of the lenses are specifically as follows: f1 / f11 = -0.436; f1 / f12 = 0.528; f1 / f13 = 0.504; f1 / f14 = 0.425.

[0074] More specifically, in this embodiment, the focal lengths of the first lens group 1 and each of the lenses are: f1 = 39.2; f11 = -89.902; f12 = 74.259; f13 = 77.827; f14 = 92.359.

[0075] Further, in order to reduce light energy loss, increase imaging clarity, protect the scale surface, and further optimize the processing flow to meet the design requirements, in this embodiment, the first lens 11 and the second lens 12 are adhesively connected to form an adhesive component, improving the image quality of the optical system.

[0076] Specifically, the fifth lens 21 has a negative optical power, the sixth lens 22 has a negative optical power, and the seventh lens 23 has a positive optical power; the focal length of the fifth lens 21 is f21, the focal length of the sixth lens 22 is f22, and the focal length of the seventh lens 23 is f23. Each lens in the second lens group 2 satisfies the following conditions:

[0077] 0.673 < f2 / f21 < 1.009, and 0.409 < f2 / f22 < 0.614, and -0.439 < f2 / f23 < -0.293.

[0078] More specifically, in this embodiment, the fifth lens 21 is a convex-concave aspherical lens with a negative optical power, that is, the object side of the fifth lens 21 is convex and the image side is concave. The sixth lens 22 is a biconcave aspherical lens with a negative optical power. The seventh lens 23 is a biconvex spherical lens with a positive optical power; the focal length ratios of the second lens group 2 to each of the lenses are as follows:

[0079] f2 / f21 = 0.807; f2 / f22 = 0.491; f2 / f23 = -0.351.

[0080] More specifically, in this embodiment, the focal length values of the second lens group 2 and each lens in the second lens group 2 are: f2 = -7.7; f21 = -9.556; f22 = -15.706; f23 = 21.972.

[0081] Specifically, the eighth lens 31 has a positive optical power, the ninth lens 32 has a positive optical power, the tenth lens 33 has a positive optical power, the eleventh lens 34 has a negative optical power, and the twelfth lens 35 has a positive optical power; the focal length of the eighth lens 31 is f31, the focal length of the ninth lens 32 is f32, the focal length of the tenth lens 33 is f33, the focal length of the eleventh lens 34 is f34, and the focal length of the twelfth lens 35 is f35. Each lens in the third lens group 3 satisfies the following conditions:

[0082] 0.733 < f3 / f31 < 1.100, and 1.009 < f3 / f32 < 1.514, and 0.345 < f3 / f33 < 0.517, and -3.340 < f3 / f34 < -2.226, and 0.561 < f3 / f35 < 0.842.

[0083] More specifically, the eighth lens 31 is a convex-concave aspherical lens with a positive optical power, that is, the object side of the eighth lens is convex and the image side is concave. The ninth lens 32 is a biconvex spherical lens with a positive optical power, the tenth lens 33 is a biconvex spherical lens with a positive optical power, the eleventh lens is a biconcave spherical lens with a negative optical power, and the twelfth lens 35 is a convex-concave aspherical lens with a positive optical power, that is, the object side of the twelfth lens 35 is convex and the image side is concave. The focal length ratios of the third lens group 3 to each lens are as follows:

[0084] f3 / f31 = 0.880; and f3 / f32 = 1.211; and f3 / f33 = 0.414; and f3 / f34 = -2.672; and f3 / f35 = 0.674.

[0085] More specifically, in this embodiment, the focal length values of the second lens group 2 and each lens in the second lens group 2 are: f3 = 27.2; f31 = 30.889; f32 = 22.442; f33 = 65.717; f34 = -10.175; f35 = 40.354.

[0086] Further, in order to reduce light energy loss, increase imaging clarity, protect the scale surface, and further optimize the processing process to meet the design requirements, in this embodiment, the tenth lens 33 and the eleventh lens 34 are glued together to form a glued part, improving the image quality of the optical system.

[0087] Specifically, the thirteenth lens 41 has a positive optical power, the fourteenth lens 42 has a positive optical power, and the fifteenth lens 43 has a negative optical power; the focal length of the thirteenth lens 41 is f41, the focal length of the fourteenth lens 42 is f42, and the focal length of the fifteenth lens 43 is f43. The lenses in the fourth lens group 4 satisfy the following conditions:

[0088] 0.225 < f4 / f41 < 0.337, and 0.998 < f4 / f42 < 1.497, and -0.567 < f4 / f43 < -0.378.

[0089] More specifically, in this embodiment, the thirteenth lens 41 is a convex-concave spherical lens with a positive optical power, the fourteenth lens 42 is a biconvex spherical lens with a positive optical power, and the fifteenth lens 43 is a concave-convex spherical lens with a negative optical power. That is, the object side surface of the fifteenth lens 43 is concave, and the image side surface is convex; the ratio of the focal length of the fourth lens group 4 to that of each lens therein is as follows:

[0090] f4 / f41 = 0.270; f4 / f42 = 1.197; f4 / f43 = -0.454.

[0091] More specifically, in this embodiment, the focal length values of the fourth lens group 4 and each lens in the fourth lens group 4 are: f4 = 20.2; f41 = 74.794; f42 = 16.861; f43 = -44.486.

[0092] Furthermore, the fourteenth lens 42 and the fifteenth lens 43 are adhesively connected to improve the image quality of the optical system.

[0093] Specifically, the sixteenth lens 51 has a positive optical power. In one embodiment, the sixteenth lens 51 is a concave-convex spherical lens with a positive optical power. That is, the object side surface of the sixteenth lens 51 is concave, and the image side surface is convex. The focal length of the sixteenth lens 51 is f51, where f5 = f'51 = 426.4.

[0094] Furthermore, the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 are all glass spherical lenses; the fifth lens 21 and the sixth lens 22 are both glass aspherical lenses; the seventh lens 23 is a glass spherical lens; the eighth lens 31 is a glass aspherical lens; the ninth lens 32, the tenth lens 33, and the eleventh lens 34 are glass spherical lenses; the twelfth lens 35 is a glass aspherical lens; and the thirteenth lens 41, the fourteenth lens 42, and the fifteenth lens 43 are glass spherical lenses. Because glass lenses can effectively resist lens deformation due to heat, they are less prone to focus shift due to thermal expansion and contraction, thus ensuring the stability of the zoom system under temperature changes.

[0095] Because resin lenses are highly impact-resistant, lightweight, and low-cost, in this embodiment, the sixteenth lens 51 is a plastic aspherical lens. The zoom system uses a glass-plastic hybrid material, which not only saves costs and provides strong impact resistance but also ensures system stability and adaptability to high and low temperatures.

[0096] It should be noted that the characteristic of aspherical lenses is that the curvature changes continuously from the center to the periphery of the lens. Unlike spherical lenses, which have a constant curvature from the center to the periphery, aspherical lenses have better curvature radius characteristics, which has the advantages of improving distortion aberration and astigmatism. By using aspherical lenses, aberrations that occur during imaging can be eliminated as much as possible, thereby improving the image quality of the lens. Furthermore, using glass lenses can reduce the impact of temperature on the optical performance of the lens.

[0097] By rationally allocating the lens power and adjusting the glass shape and material combination, chromatic aberration and secondary spectrum are effectively eliminated, and spherical aberration, coma, astigmatism and other aberrations on each lens are mutually compensated and canceled out to achieve a clear imaging effect, so as to achieve optimal correction of higher-order aberrations and chromatic aberration.

[0098] Specifically, in one embodiment, the refractive index, radius of curvature, and thickness spacing of the lens material are shown in the table below:

[0099]

[0100]

[0101] Furthermore, in this embodiment, the aspherical surface shape of the aspherical lens satisfies the following condition:

[0102]

[0103] 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 quadratic coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola; when the k coefficient is equal to -1, it is a parabola; when the k coefficient is between -1 and 0, it is an ellipse; when the k coefficient is equal to 0, it is a circle; and when the k coefficient is greater than 0, it is an oval), and A, B, C, D, E, F, and G are higher-order aspherical coefficients (please refer to Table 2 below). The shape and size of the aspherical surfaces of the object side and image side of the lens can be set by using the above parameters.

[0104] Table 2 Conic and Aspherical Coefficients for Aspherical Lenses

[0105]

[0106]

[0107] Specifically, the zoom system further includes an aperture stop 7, which is located between the second lens group 2 and the third lens group 3; that is, the aperture stop 7 is located between the seventh lens 23 and the eighth lens 31.

[0108] Specifically, in this embodiment, the zoom system further includes a filter located between the fifth lens group 5 and the image plane 6. The filter is used to filter out unnecessary wavelengths of light and stray light to reduce optical noise and reduce difficulties for subsequent photoelectric module processing. The filter can also be used to adjust the color saturation of the image during final imaging, thereby improving image quality.

[0109] Specifically, the image plane 6 can be understood as the surface of the photosensitive chip facing the object, that is, the surface of a camera element such as a CCD or CMOS. It can be understood that the light carrying the information of the object being photographed can pass through the first lens group 1, the second lens group 2, the aperture 7, the third lens group 3, the fourth lens group 4, the fifth lens group 5, and the filter in sequence and finally be imaged on the image plane 6.

[0110] Specifically, the zoom system satisfies the following conditions: in, The effective aperture of the first lens 11 is denoted by TTL, and the total optical length of the zoom system is denoted by TTL.

[0111] Specifically, the zoom system satisfies the following conditions: -0.301 < ΔZ1W-T / TTL < -0.231, and 0.096 < ΔZ2W-T / TTL < 0.125; where ΔZ1W-T is the relative displacement of the fifth lens 21 when the zoom system is in the wide-angle position and when the zoom system is in the telephoto position, ΔZ2W-T is the relative displacement of the eighth lens 31 when the zoom system is in the wide-angle position and when the zoom system is in the telephoto position, and TTL is the total optical length of the zoom system.

[0112] Specifically, in this embodiment, the size of image plane 6 is set to φ7.7mm, achieving the following performance parameters:

[0113] The focal length at the wide-angle end is fw = 5.59mm, and the focal length at the telephoto end is ft = 151.10mm; the aperture number at the wide-angle end is f / 1.66, and the aperture number at the telephoto end is f / 4.97; the optical distortion range is between -4% and 4%; the total optical length of the zoom system is TTL = 92mm.

[0114] Table 3. Zoom magnification data for the zoom system at wide-angle, mid-magnification, and telephoto ends.

[0115] Wide-angle end Intermediate multiplier Observation Depth T(7) 0.450 23.958 24.924 T(13) 25.574 2.066 1.100 T(14) 10.264 3.921 0.100 T(23) 4.076 10.438 22.811 T(28) 9.581 9.562 1.009

[0116] Table 4 shows the focal length values ​​of a specific embodiment of the zoom system lens at the wide-angle end, mid-magnification position, and telephoto end.

[0117] Focal length / mm Wide-angle end 5.6 Intermediate multiplier 82.8 Observation Depth 151.1

[0118] In this embodiment, please refer to Figures 1 to 3 The diagram shows the structure of the zoom system when it is at the wide-angle end, the intermediate magnification, and the telephoto end; wherein, the intermediate magnification can be understood as the position diagram of each lens group in the zoom system when the zoom system is between the wide-angle end and the telephoto end.

[0119] Figures 4 to 5 The diagrams show the longitudinal aberration and field curvature / distortion of the zoom system at the wide-angle end, respectively. In the diagrams, S and T represent the aberrations corresponding to the sagittal and meridional image planes, respectively.

[0120] Please refer to Figures 6 to 7 , which are the aberration diagram and field curvature / distortion diagram of the zoom system at the intermediate magnification. S and T in the diagram are the aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0121] Please refer to Figures 8 to 9, are the spherical aberration diagram and field curvature / distortion diagram of the zoom system when it is at the telephoto end. S and T in the diagram are the aberrations corresponding to the sagittal image plane and the meridional image plane, respectively.

[0122] As can be seen from the above figures, the zoom system in this embodiment can achieve good correction of spherical aberration, field curvature, and distortion at intermediate magnification, wide-angle end, and telephoto end.

[0123] As can be seen from the above figures, the zoom system in this embodiment can achieve good correction of spherical aberration, field curvature, and distortion at intermediate magnification, wide-angle end, and telephoto end.

[0124] The above description is merely an optional 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's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An image forming apparatus characterized by comprising: The imaging device comprises a zoom system having an object side and an image side oppositely arranged along an optical axis direction, the zoom system comprising: a first lens group fixedly arranged in the lens barrel, the first lens group having positive refractive power; a second lens group movably arranged along the extension direction of the optical axis, the second lens group being used to zoom the zoom system from a wide-angle end to a telephoto end when moving towards the image side, the second lens group having negative refractive power; a third lens group movably arranged along the extension direction of the optical axis, the third lens group having positive refractive power; and a fourth lens group movably arranged along the extension direction of the optical axis to focus the zoom system when moving along the optical axis direction, the fourth lens group having positive refractive power; a fifth lens group fixedly arranged in the lens barrel, the fifth lens group having positive refractive power; wherein the focal length of the zoom system at the wide-angle end is fw, the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, the focal length of the fourth lens group is f4, and the focal length of the fifth lens group is f5, the zoom system satisfying the following conditions: 0.119<fw / f1<0.178, and -0.906<fw / f2<-0.604, and 0.171<fw / f3<0.257, and 0.231<fw / f4<0.346, and 0.011<fw / f5<0.016; the first lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the object side to the image side; the second lens group comprises a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object side to the image side; the third lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from the object side to the image side; the fourth lens group comprises a thirteenth lens, a fourteenth lens and a fifteenth lens arranged in sequence from the object side to the image side; the fifth lens group comprises a sixteenth lens; the first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, and the fourth lens has positive refractive power; the first lens and the second lens are cemented together; the focal length of the first lens is f11, the focal length of the second lens is f12, the focal length of the third lens is f13, and the focal length of the fourth lens is f14, the lenses in the first lens group satisfying the following conditions: -0.545<f1 / f11<-0.364, and 0.440<f1 / f12<0.660, and 0.420<f1 / f13<0.630, and 0.354<f1 / f14<0.531; the fifth lens has negative refractive power, the sixth lens has negative refractive power, and the seventh lens has positive refractive power; The focal length of the fifth lens is f21, the focal length of the sixth lens is f22, the focal length of the seventh lens is f23, and each lens in the second lens group satisfies the following conditions: 0.673 < f2 / f21 < 1.009, and 0.409 < f2 / f22 < 0.614, and -0.439 < f2 / f23 < -0.293; The eighth lens has positive refractive power, the ninth lens has positive refractive power, the tenth lens has positive refractive power, the eleventh lens has negative refractive power, and the twelfth lens has positive refractive power; The tenth lens and the eleventh lens are cemented together; The focal length of the eighth lens is f31, the focal length of the ninth lens is f32, the focal length of the tenth lens is f33, the focal length of the eleventh lens is f34, and the focal length of the twelfth lens is f35. Each lens in the third lens group satisfies the following conditions: 0.733 < f3 / f31 < 1.100, and 1.009 < f3 / f32 < 1.514, and 0.345 < f3 / f33 < 0.517, and -3.340 < f3 / f34 < -2.226, and 0.561 < f3 / f35 < 0.842; The thirteenth lens has positive refractive power, the fourteenth lens has positive refractive power, and the fifteenth lens has negative refractive power; The fourteenth lens and the fifteenth lens are cemented together; The focal length of the thirteenth lens is f41, the focal length of the fourteenth lens is f42, and the focal length of the fifteenth lens is f43. Each lens in the fourth lens group satisfies the following conditions: 0.225 < f4 / f41 < 0.337, and 0.998 < f4 / f42 < 1.497, and -0.567 < f4 / f43 < -0.

378.

2. The imaging apparatus of claim 1, wherein The sixteenth lens has positive refractive power.

3. The imaging apparatus of claim 1, wherein The first lens, the second lens, the third lens, and the fourth lens are all glass spherical lenses; The fifth lens and the sixth lens are both glass aspherical lenses, and the seventh lens is a glass spherical lens; The eighth lens is a glass aspherical lens, the ninth lens, the tenth lens, and the eleventh lens are glass spherical lenses, and the twelfth lens is a glass aspherical lens; The thirteenth lens, the fourteenth lens, and the fifteenth lens are glass spherical lenses; The sixteenth lens is a plastic aspherical lens.

4. The imaging apparatus of claim 1, wherein The zoom system satisfies the following condition: 0.369 < øL11 / TTL < 0.451; Wherein, øL11 is the effective clear aperture of the first lens, and TTL is the total optical length of the zoom system.

5. The imaging apparatus of claim 1, wherein The zoom system satisfies the following conditions: -0.301 < ΔZ1 W-T / TTL < -0.231, and 0.096 < ΔZ2 W-T / TTL < 0.125; Wherein, ΔZ1W-T is the relative displacement of the fifth lens when the zoom system is at the wide-angle end position and the zoom system is at the telephoto end position, ΔZ2W-T is the relative displacement of the eighth lens when the zoom system is at the wide-angle end position and the zoom system is at the telephoto end position, and TTL is the total optical length of the zoom system.

Images