Zoom optical system

Abstract

The utility model discloses a zoom optical system, and relates to the technical field of zoom optical systems, the zoom optical system is provided with an object side and an image side which are oppositely arranged along the direction of an optical axis, the zoom optical system comprises a first lens group, a second lens group and an image surface which are sequentially arranged from the object side to the image side, the first lens group and the second lens group are movably arranged along the direction of an optical axis, the second lens group is used for zooming, the first lens group is used for focusing, the maximum optical total length of the zoom optical system is within 51mm, the focal length of the zoom optical system at a 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, and the zoom optical system meets the following conditions: fw, f1, f2 and fw respectively. -0.55 < = fw / f1 < =-0.1; and 0.2323 < = fw / f2 < = 0.75. By means of the arrangement, the zoom optical system has the field angle of 140 degrees or above when located at the wide-angle end, and the zoom optical system is wide in view field, small in size, low in cost, high in resolution ratio and capable of meeting the requirement for face recognition in the high-low-temperature environment.

Description

TECHNICAL FIELD

[0001] The utility model relates to zoom optical system technical field, especially zoom optical system. BACKGROUND

[0002] The zoom optical system can be applied to various monitoring scenes because its focal length is variable, for example, meeting the requirements of image collection of long-distance monitoring scene and close-range face recognition in the security market.

[0003] However, the existing lens has a small aperture, cannot meet the requirements of image brightness in low-illumination environment, cannot take into account large image surface and small volume, cannot meet the space requirements of the lens, has low pixels, and cannot take into account infrared performance and high-low temperature performance, resulting in the inability to meet the real-time requirements of face recognition in high-low temperature environment. CONTENT

[0004] The utility model discloses a zoom optical system, aiming at improving the existing zoom optical system cannot meet the requirements of image brightness in low-illumination environment, cannot take into account large image surface and small volume, cannot meet the space requirements of the lens, has low pixels, and cannot take into account infrared performance and high-low temperature performance, resulting in the inability to meet the real-time requirements of face recognition in high-low temperature environment.

[0005] To achieve the above object, the utility model provides a zoom optical system, which has an object side and an image side arranged oppositely along the optical axis direction, and comprises a first lens group, a second lens group and an image surface arranged in sequence from the object side to the image side.

[0006] The focal length of the zoom optical 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, and the zoom optical system satisfies the following conditions:

[0007] -0.55≤fw / f1≤-0.1; and 0.2323≤fw / f2≤0.75.

[0008] In an embodiment, the optical power of the first lens group is negative.

[0009] The optical power of the second lens group is positive.

[0010] In an embodiment, the first lens group comprises a first lens, a second lens and a third lens arranged in sequence from the object side to the image side.

[0011] The focal length of the first lens is f11, the focal length of the second lens is f12, and the focal length of the third lens is f13, wherein 0.67≤f1 / f11≤0.90; 0.44≤f1 / f12≤0.60; and -0.41≤f1 / f13≤-0.30.

[0012] In an embodiment, the object side surface of the first lens is convex, and the image side surface is concave.

[0013] The object side surface of the second lens is concave, and the image side surface is concave.

[0014] The object side surface of the third lens is convex, and the image side surface is convex.

[0015] In an embodiment, the second lens group includes, in order from the object side to the image side, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0016] The focal length of the fourth lens is f21, the focal length of the fifth lens is f22, the focal length of the sixth lens is f23, the focal length of the seventh lens is f24, and the focal length of the eighth lens is f25, wherein 0.68≤f2 / f21≤0.91, 1.34≤f2 / f22≤1.81, 1.95≤f2 / f23≤2.64, -0.66≤f2 / f24≤-0.49, and 1.08≤f2 / f25≤1.46.

[0017] In an embodiment, the object side surface of the fourth lens is convex, and the image side surface is convex.

[0018] The object side surface of the fifth lens is convex, and the image side surface is convex.

[0019] The object side surface of the sixth lens is concave, and the image side surface is convex.

[0020] The object side surface of the seventh lens is concave, and the image side surface is concave.

[0021] The object side surface of the eighth lens is convex, and the image side surface is concave.

[0022] In an embodiment, the target surface size of the zoom optical system is φ, and φ≤6.6mm.

[0023] In an embodiment, the aperture of the zoom optical system is Fno, and 1.57≤Fno≤2.64.

[0024] In an embodiment, the focal length of the zoom optical system is f, and 3.46mm≤f≤10.48mm.

[0025] In an embodiment, the zoom optical system further comprises a diaphragm and a filter, the diaphragm is arranged between the first lens group and the second lens group, and the filter is arranged on a side of the second lens group towards an image side.

[0026] In the technical scheme of the utility model, the first lens group and the second lens group are movably arranged along the optical axis direction, the second lens group is movably arranged along the optical axis direction, used for zooming the zoom optical system, and the first lens group is movably arranged along the optical axis direction, used for focusing the zoom optical system, so that the zoom optical system keeps the image plane clear during zooming, by limiting the focal length ratio of the first lens group and the zoom optical system at the wide-angle end within the range of -0.55 <= fw / f1 <= -0.1, limiting the focal length ratio of the second lens group and the zoom optical system at the wide-angle end within the range of 0.2323 <= fw / f2 <= 0.75, and limiting the maximum optical total length of the zoom optical system within 51mm, the zoom optical system has a field of view angle of more than 140 degrees at the wide-angle end, so that a zoom optical system with a wide field of view, small volume, low cost, high resolution and capable of meeting the demand of face recognition under high and low temperature environment is provided. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained from the structures shown in the drawings without creative labor for those skilled in the art.

[0028] Figure 1 The structural schematic diagram of an embodiment of the zoom optical system provided by the utility model is shown in the figure.

[0029] Figure 2 The LON schematic diagram of the zoom optical system provided by the utility model at the wide-angle end is shown in the figure.

[0030] Figure 3 The LON schematic diagram of the zoom optical system provided by the utility model at the telephoto end is shown in the figure.

[0031] BRIEF DESCRIPTION OF DRAWINGS

[0032] 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; 3, diaphragm; 4, filter.

[0033] The purposes, functional features and advantages of the utility model will be further explained in combination with embodiments and with reference to the drawings. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0035] It should be noted that if the embodiments of the utility model 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 condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0036] In addition, if the embodiments of the utility model involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features with "first" and "second" can explicitly or implicitly include at least one feature. In addition, if "and / or" or "and / or" appears in the entire text, it means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skill in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the utility model.

[0037] The utility model provides a kind of zoom optical system. It aims at improving the determination that existing zoom optical system cannot meet the requirement of image to brightness under low-illumination environment, and cannot take into account large image surface and small volume, cannot meet the space requirement of lens, pixel is lower, and cannot take into account infrared performance and high-low temperature performance, leading to unable to meet the real-time requirement of face recognition under high-low temperature environment.

[0038] Please refer to Figure 1In an embodiment of the utility model, this zoom optical system 100 has opposite arrangement along the optical axis direction object side and image side, the zoom optical system 100 includes the first mirror group 1, the second mirror group 2 and the image plane in turn from object side to image side, the first mirror group 1 and the second mirror group 2 are all along the optical axis direction activity setting, the second mirror group 2 is used for zooming, the first mirror group 1 is used for focusing, and the maximum optical total length of the zoom optical system 100 is within 51mm, the focal length of the zoom optical system 100 at wide-angle end is fw, the focal length of the first mirror group 1 is f1, the focal length of the second mirror group 2 is f2, and the zoom optical system 100 satisfies the following conditions: -0.55≤fw / f1≤-0.1; and 0.2323≤fw / f2≤0.75.

[0039] In the technical scheme of the utility model, the first mirror group 1 and the second mirror group 2 are all along the optical axis direction activity setting, the second mirror group 2 is along the optical axis direction activity, to zoom the zoom optical system 100, and the first mirror group 1 is along the optical axis direction cooperative movement, to focus the zoom optical system 100, so that the zoom optical system 100 keeps the imaging of the image plane clear in the zooming process, thus, by limiting the focal length ratio of the first mirror group 1 and the zoom optical system 100 at wide-angle end within the range of -0.55≤fw / f1≤-0.1, and limiting the focal length ratio of the second mirror group 2 and the zoom optical system 100 at wide-angle end within the range of 0.2323≤fw / f2≤0.75, and limiting the maximum optical total length of the zoom optical system 100 within 51mm, so that the zoom optical system 100 has a field of view angle of more than 140° at wide-angle end, to provide a zoom optical system 100 with wide field of view, small volume, low cost, high resolution and capable of meeting the demand of face recognition under high and low temperature environment.

[0040] It should be noted that the utility model does not limit the specific driving form of the first mirror group 1 and the second mirror group 2 along the optical axis activity, in an embodiment of the utility model, the driving force of the first mirror group 1 and the second mirror group 2 along the optical axis activity can be driving motor driving, and in another embodiment of the utility model, the driving force of the first mirror group 1 and the second mirror group 2 along the optical axis activity can also be artificial manual adjustment, in still another embodiment of the utility model, the driving force of one of the first mirror group 1 and the second mirror group 2 along the optical axis activity is driving motor driving, and the driving force of the other along the optical axis activity is artificial manual adjustment. In actual setting, it can be selected according to demand, and the utility model does not limit here.

[0041] It can be understood that, in the utility model, the first mirror group 1's focal power is negative, the second mirror group 2's focal power is positive. So set up, through the cooperation of the focal power of multiple mirror groups, to ensure the imaging quality of the zoom optical system 100.

[0042] In addition, in the utility model, the focal length of the zoom optical system 100 is f, 3.46mm≤f≤10.48mm.

[0043] Specifically, in an embodiment of the utility model, the first mirror group 1 includes the first lens 11 of negative focal power, the second lens 12 of negative focal power and the third lens 13 of positive focal power arranged in sequence along the optical axis direction.

[0044] In a specific embodiment of the utility model, the focal length of the first lens 11 is f11, the focal length of the second lens 12 is f12, and the focal length of the third lens 13 is f13.

[0045] It can be understood that the utility model does not limit the specific value of the focal length of the first lens 11, the second lens 12 and the third lens 13, and in the embodiment of the utility model, the first lens 11, the second lens 12 and the third lens 13 can be set to any value in the range.

[0046] In addition, in the embodiment, the first lens 11 adopts glass spherical lens, so set up, the lens of glass material can reduce the influence of temperature on the optical performance of the lens, and the glass lens is not easy to be affected by thermal expansion and contraction to appear running focus phenomenon, so the glass lens can well resist the problem of lens thermal deformation, and keep the high precision of the lens for a long time, the second lens 12 and the third lens 13 adopt plastic aspherical lens, so set up, the aspherical lens has better curvature radius characteristics, has the advantages of improving distortion aberration and improving astigmatism aberration, after adopting the aspherical lens, the aberration appearing during imaging can be eliminated as much as possible, so as to improve the imaging quality of the lens, and at the same time, the plastic aspherical lens can also reduce the manufacturing cost of the projection optical system.

[0047] At the same time, setting the second lens 12 and the third lens 13 as plastic aspherical lens is also beneficial to the collection of light rays of the zoom optical system 100, can effectively increase the field of view range, correct distortion and reduce the volume.

[0048] Specifically, in an embodiment of the utility model, the object side of the first lens 11 is convex, and the image side is concave, the object side of the second lens 12 is concave, and the image side is concave, the object side of the third lens 13 is convex, and the image side is convex.

[0049] Further, in another embodiment of the present application, the second lens group 2 comprises a fourth lens 21, a fifth lens 22, a sixth lens 23, a seventh lens 24 and an eighth lens 25 arranged in order from the object side to the image side.

[0050] In further embodiments of the present application, the focal length of the fourth lens 21 is f21, the focal length of the fifth lens 22 is f22, the focal length of the sixth lens 23 is f23, the focal length of the seventh lens 24 is f24, and the focal length of the eighth lens 25 is f25, wherein 0.68≤f2 / f21≤0.91, 1.34≤f2 / f22≤1.81, 1.95≤f2 / f23≤2.64, -0.66≤f2 / f24≤-0.49, and 1.08≤f2 / f25≤1.46.

[0051] It can be understood that the present application does not limit the specific values of the focal lengths of the fourth lens 21, the fifth lens 22, the sixth lens 23, the seventh lens 24 and the eighth lens 25, and in the embodiments of the present application, the focal lengths of the fourth lens 21, the fifth lens 22, the sixth lens 23, the seventh lens 24 and the eighth lens 25 can be set to any value within the range.

[0052] It should be further noted that in the present embodiment, the fourth lens 21 is a glass spherical lens, and the fifth lens 22, the sixth lens 23, the seventh lens 24 and the eighth lens 25 are plastic aspherical lenses.

[0053] In further embodiments of the present application, the object side of the fourth lens 21 is convex, the image side is convex, the object side of the fifth lens 22 is convex, the image side is convex, the object side of the sixth lens 23 is concave, the image side is convex, the object side of the seventh lens 24 is concave, the image side is concave, and the object side of the eighth lens 25 is convex, the image side is concave.

[0054] It should be noted that in the present application, the target surface size of the zoom optical system 100 is φ, and φ≤6.6mm.

[0055] It should be further noted that in the present application, the aperture of the zoom optical system 100 is Fno, and 1.57≤Fno≤2.64. In this way, the zoom optical system 100 has the characteristic of a large aperture, so that the zoom optical system 100 still has excellent imaging effect in a low-illumination environment, can meet the imaging needs of bright and dark environments, and realizes night vision function.

[0056] In addition, in the embodiment of the utility model, the zoom optical system 100 further includes diaphragm 3 and filter 4, diaphragm 3 is located between first mirror group 1 and second mirror group 2, filter 4 is located on the side of second mirror group 2 towards the image side. Diaphragm 3 is used to adjust luminous flux according to actual conditions, improve imaging quality, the setting of filter 4 can effectively filter out stray light of non-working waveband, to reduce light noise, reduce the difficulty for subsequent optoelectronic module processing part, thereby improving the imaging quality.

[0057] Specifically, in a specific embodiment of the utility model, the object side of the first lens 11 is S1, the image side is S2, the object side of the second lens 12 is S3, the image side is S4, the object side of the third lens 13 is S5, the image side is S6, the object side of the diaphragm 3 is S7, the object side of the fourth lens 21 is S8, the image side is S9, the object side of the fifth lens 22 is S10, the image side is S11, the object side of the sixth lens 23 is S12, the image side is S13, the object side of the seventh lens 24 is S14, the image side is S15, the object side of the eighth lens 25 is S16, the image side is S17, the object side of the filter 4 is S18, the image side is S19, and the image plane is S20.

[0058] It should be noted that in the embodiment, the lens face type, curvature radius, thickness, material refractive index and material Abbe number of the zoom optical system 100 are as shown in Table 1:

[0059] Table 1

[0060]

[0061]

[0062] It can be understood that in the embodiment, the second lens 12, the third lens 13, the fifth lens 22, the sixth lens 23, the seventh lens 24 and the eighth lens 25 are all aspherical lenses. The aspherical lens has the characteristic that the curvature is continuously changed from the center of the lens to the periphery of the lens. Unlike the spherical lens with constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has better curvature radius characteristics, has the advantages of improving distortion and improving astigmatism, and after using the aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens.

[0063] Correspondingly, in the embodiment, the first lens 11 and the fourth lens 21 are provided as spherical lenses. The use of spherical lenses reduces costs, has low assembly sensitivity and improves the yield of finished products under the premise of ensuring image quality and reliability.

[0064] Further, in the present embodiment, the aspherical surface shape of the aspherical lens satisfies the following condition:

[0065]

[0066] where c is the radius corresponding to the curvature, y is the radial coordinate (which has the same unit as the lens length), k is the conic quadratic curve 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 a flat circle), A, B, C, D, E, F, G, H are high-order aspherical coefficients (see Table 2 below), and the shape and size of the lens object side and image side aspherical surfaces can be set by the above parameters. Please refer to Table 2 below:

[0067] Table 2 Conic coefficients and aspherical coefficients of aspherical lenses

[0068]

[0069]

[0070] In this way, by reasonably allocating the lens power, adjusting the glass shape and material matching, effectively eliminating chromatic aberration and secondary spectrum, the spherical aberration, coma, astigmatism and other aberrations on each lens are compensated and offset, to achieve clear imaging effect, to achieve optimal correction of high-order aberration and chromatic aberration.

[0071] In addition, the interval between each lens group of the zoom optical system 100 in the present embodiment changes from the Wide end (wide angle end) to the Tele end (telephoto end) as shown in Table 3:

[0072] Table 3

[0073] Surface Number Wide Angle Telescopic 6 13.4 1.1 7 7.7 1.7 17 0.26 6.2

[0074] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the contents of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A zoom optical system characterized in that, The zoom optical system has an object side and an image side oppositely arranged along an optical axis direction, and comprises a first lens group, a second lens group and an image plane arranged in sequence from the object side to the image side, the first lens group and the second lens group are movably arranged along the optical axis direction, the second lens group is used for zooming, the first lens group is used for focusing, and a maximum total optical length of the zoom optical system is within 51 mm; wherein, a focal length of the zoom optical system at a wide-angle end is fw, a focal length of the first lens group is f1, a focal length of the second lens group is f2, and the zoom optical system satisfies the following conditions: -0.55≤fw / f1≤-0.1; and 0.2323≤fw / f2≤0.

75.

2. The zoom optical system according to claim 1, characterized by The first lens group has a negative refractive power. The second lens group has a positive refractive power.

3. The zoom optical system according to claim 1, wherein The first lens group comprises a first lens, a second lens and a third lens arranged in sequence from the object side to the image side. The first lens has a focal length f11, the second lens has a focal length f12, and the third lens has a focal length f13, wherein 0.67≤f1 / f11≤0.90; and 0.44≤f1 / f12≤0.60; and -0.41≤f1 / f13≤-0.

30.

4. The zoom optical system according to claim 3, characterized by The object side surface of the first lens is a convex surface, and the image side surface is a concave surface. The object side surface of the second lens is a concave surface, and the image side surface is a concave surface. The object side surface of the third lens is a convex surface, and the image side surface is a convex surface.

5. The zoom optical system according to claim 1, wherein The second lens group comprises a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence from the object side to the image side. The fourth lens has a focal length f21, the fifth lens has a focal length f22, the sixth lens has a focal length f23, the seventh lens has a focal length f24, and the eighth lens has a focal length f25, wherein 0.68≤f2 / f21≤0.91, and 1.34≤f2 / f22≤1.81, and 1.95≤f2 / f23≤2.64, and -0.66≤f2 / f24≤-0.49, and 1.08≤f2 / f25≤1.

46.

6. The zoom optical system according to claim 5, characterized by The object side surface of the fourth lens is a convex surface, and the image side surface is a convex surface. The object side surface of the fifth lens is a convex surface, and the image side surface is a convex surface. The object side surface of the sixth lens is a concave surface, and the image side surface is a convex surface. The object side surface of the seventh lens is a concave surface, and the image side surface is a concave surface. The object side surface of the eighth lens is a convex surface, and the image side surface is a concave surface.

7. The zoom optical system according to claim 1, wherein The target surface size of the zoom optical system is φ, and φ≤6.6 mm.

8. The zoom optical system according to claim 1, wherein The aperture of the zoom optical system is Fno, and 1.57≤Fno≤2.

64.

9. The zoom optical system according to claim 1, wherein The focal length of the zoom optical system is f, and 3.46 mm≤f≤10.48 mm.

10. The zoom optical system according to claim 1, wherein The zoom optical system further comprises a diaphragm and a filter, the diaphragm is arranged between the first lens group and the second lens group, and the filter is arranged on a side of the second lens group towards the image side.

Images