Fixed-focus optical system and surveillance camera equipment

Abstract

The present invention discloses a fixed-focus optical system and a surveillance camera device. The fixed-focus optical system includes a housing and a lens group. The lens group includes a first lens group with positive optical power, a second lens group with negative optical power, and a third lens group with positive optical power, which are arranged in sequence from the object side to the image side. The first lens group and the third lens group are fixedly mounted on the housing, and the second lens group is movably mounted on the housing along the optical axis. In the technical solution of the present invention, through the reasonable arrangement of the three lens groups and the conditional restriction of the focal length of the fixed-focus optical system and the focal length ratio of each lens group, the fixed-focus optical system achieves an ultra-long focal length of f500mm, and the second lens group can be movably arranged to achieve focusing under different objective lenses, work in an unstable environment and ensure the resolution of the lens, thereby improving the technical problem of poor resolution performance in extreme environments in the prior art.

Description

Technical Field

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[0001] The present invention relates to the technical field of optical system design, and particularly relates to a fixed-focus optical system and a monitoring camera device. Background Art

[0002] At present, fixed-focus optical systems for monitoring generally have the following disadvantages: short focal length, inability to capture clearly at long distances, inability to quickly focus at different object distances, the lens cannot work or the resolution decreases in extreme environments, etc. There is no lens in the current market that fully takes into account the above disadvantages. Only a few lenses improve certain aspects at the expense of other aspects. There are also lenses that use multiple glass aspherical lenses to meet the resolution requirements and ensure the use in extreme environments, resulting in an increase in cost and affecting the popularization and promotion of the lens. Summary of the Invention

[0003] The main object of the present invention is to provide a fixed-focus optical system and a monitoring camera device, aiming to improve the technical problem of poor resolution performance in extreme environments in the prior art.

[0004] To achieve the above object, the present invention provides a fixed-focus optical system. The fixed-focus optical system has an object side and an image side that are relatively arranged along the optical axis direction. The fixed-focus optical system includes a housing and a first lens group with a positive optical power, an aperture stop, a second lens group with a negative optical power, a third lens group with a negative optical power, and a photosensitive chip that are sequentially arranged in the housing from the object side to the image side. Among them, the first lens group and the third lens group are fixedly installed in the housing, and the second lens group is movably arranged along the extension direction of the optical axis;

[0005] Among them, the focal length of the fixed-focus optical system is f, the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the focal length of the third lens group is f3. The fixed-focus optical system satisfies the following conditions:

[0006] 2.2 < f / f1 < 3, and -4.4 < f / f2 < -3.2, and -1.8 < f / f3 < -1.2.

[0007] Optionally, the first lens group includes a first lens with a positive optical power, a second lens with a negative optical power, a third lens with a positive optical power, and a fourth lens with a negative optical power that are sequentially arranged from the object side to the image side;

[0008] 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 first lens group and the first lens, the second lens, the third lens, and the fourth lens satisfy the following conditions:

[0009] 0.15 < f1 / f11 < 21, and -0.52 < f1 / f12 < -0.38, and 0.68 < f1 / f13 < 0.92, and -0.25 < f1 / f14 < -0.18.

[0010] Optionally, the first lens and the second lens are adhesively connected;

[0011] The third lens and the fourth lens are adhesively connected.

[0012] Optionally, the optical power of the first cemented lens group formed by the first lens and the second lens is positive, the optical power of the second cemented lens group formed by the third lens and the fourth lens is positive, the focal length of the first cemented lens group is f1112, the focal length of the second cemented lens group is f1314, and the first lens group, the first cemented lens group, and the second cemented lens group satisfy the following conditions:

[0013] 0.24 < f1 / f1112 < 0.33, and 0.63 < f1 / f1314 < 0.86.

[0014] Optionally, the second lens group includes a fifth lens with positive optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power arranged in sequence from the object side to the image side;

[0015] 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 the second lens group, the fifth lens, the sixth lens, and the seventh lens satisfy the following conditions:

[0016] -0.38 < f2 / f21 < -0.28, and -1.18 < f2 / f22 < -0.87, and 2.2 < f2 / f23 < 2.98.

[0017] Optionally, the third lens group includes an eighth lens with negative optical power, a ninth lens with negative optical power, and a tenth lens with positive optical power arranged in sequence from the object side to the image side;

[0018] 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, and the third lens group, the eighth lens, the ninth lens, and the tenth lens satisfy the following conditions:

[0019] 0.72 < f3 / f31 < 0.97, and 1.0 < f3 / f32 < 1.4, and -3.5 < f3 / f33 < -2.5.

[0020] Optionally, the eighth lens and the ninth lens are adhesively connected to form a third cemented lens group, and the third cemented lens group is movably arranged in a plane perpendicular to the optical axis.

[0021] Optionally, the optical power of the third cemented lens group is negative, the focal length of the third cemented lens group is f3132, and the third lens group and the third cemented lens group satisfy the following conditions:

[0022] 3.5 < f3 / f3132 < 4.9.

[0023] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are all glass spherical lenses.

[0024] The present invention further provides a monitoring camera device, which includes a fixed-focus optical system. The fixed-focus optical system has an object side and an image side arranged oppositely along the optical axis direction. The fixed-focus optical system includes a housing and, arranged in the housing from the object side to the image side in sequence, a first lens group with positive optical power, an aperture stop, a second lens group with negative optical power, a third lens group with negative optical power, and a photosensitive chip. Among them, the first lens group and the third lens group are fixedly installed in the housing, and the second lens group is movably arranged along the extension direction of the optical axis;

[0025] Among them, the focal length of the fixed-focus optical system is f, the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the focal length of the third lens group is f3. The fixed-focus optical system satisfies the following conditions:

[0026] 2.2 < f / f1 < 3, and -4.4 < f / f2 < -3.2, and -1.8 < f / f3 < -1.2.

[0027] In the technical solution provided by the present invention, the first lens group and the third lens group are fixedly mounted on the housing, and the second lens group is movably mounted on the housing along the optical axis, wherein the second lens group is driven by an external force to move and focus along the optical axis corresponding to the positions, imaging wavelength, and imaging object distance of the first lens group and the third lens group, so that the fixed-focus optical system maintains clear imaging on the imaging surface after focusing, and the first lens group has positive focal power, the second lens group has negative focal power, and the third lens group has negative focal power. Through the reasonable arrangement of the three lens groups and the conditional restrictions on the focal length of the fixed-focus optical system and the focal length ratio of each lens group, the fixed-focus optical system achieves an ultra-long focal length of f500mm, works in an unstable environment and ensures the resolution of the lens, and can correct the image jitter caused by external force by adjusting the eccentricity of the lens in the XY direction, thereby improving the technical problem of poor resolution performance in extreme environments in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0029] Figure 1 A schematic structural diagram of the fixed-focus optical system provided by the present invention;

[0030] Figure 2 for Figure 1 Aberration diagram of the fixed-focus optical system in ;

[0031] Figure 3 for Figure 1 Field curvature diagram of fixed focus optical system in;

[0032] Figure 4 for Figure 1 Distortion diagram of the fixed-focus optical system in .

[0033] Description of Figure Numbers:

[0034] Label name Label name 1 First lens group 23 Seventh lens 11 First lens 3 The third lens group 12 Second lens 31 Eighth lens 13 The third lens 32 Ninth lens 14 Fourth lens 33 Tenth lens 2 Second lens group 4 aperture 21 Fifth lens 5 Photosensitive chip 22 Sixth lens 6 filter

[0035] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] It should be noted that if a directional indication is involved in an embodiment of the present invention, the directional indication is 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 indication will also change accordingly.

[0038] 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 defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement it. 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.

[0039] The mainstream high-quality zoom surveillance lenses currently on the market require a sufficiently large field of view to achieve a wider field of view, often designed to have a wide-angle effect. The design concept of wide-angle lenses sacrifices lens distortion, allowing as much light as possible with extreme distortion. As a result, the edges of the image are severely compressed due to the huge distortion, making it impossible to distinguish image information around the frame, resulting in poor image quality. In outdoor surveillance, high requirements for image distortion are placed on ensuring clear coverage of a large area. Existing surveillance lenses generally use multiple glass aspherical lenses to reduce the effects of distortion, but the high manufacturing cost cannot meet market demand.

[0040] The present invention provides a fixed-focus optical system, which aims to improve the technical problem of poor resolution performance in extreme environments in the prior art. Figure 1 , the accompanying drawings show a specific embodiment of the fixed-focus optical system.

[0041] Figures 1 to 4 This is the first embodiment of the fixed-focus optical system provided by the present invention.

[0042] Please refer to Figure 1 , the fixed-focus optical system has an object side and an image side that are oppositely arranged along the optical axis direction. The fixed-focus optical system includes a housing (not shown in the figure) and a plurality of lens groups. The housing extends along the optical axis direction. The lens groups include a first lens group 1 with a positive optical power, a second lens group 2 with a negative optical power, an aperture 4, a third lens group 3 with a negative optical power, and a photosensitive chip 5, which are arranged in sequence from the object side to the image side. Moreover, the optical power of the fifth lens 21 group can be positive or negative. Among them, the first lens group 1 and the third lens group 3 are fixedly installed on the housing, and the second lens group 2 is movably arranged along the extension direction of the optical axis. Among them, the focal length of the fixed-focus optical system is f, the focal length of the first lens group 1 is f1, the focal length of the second lens group 2 is f2, and the focal length of the third lens group 3 is f3. The fixed-focus optical system satisfies the following conditions: 2.2 < f / f1 < 3, and -4.4 < f / f2 < -3.2, and -1.8 < f / f3 < -1.2.

[0043] In the technical solution provided by the present invention, the first lens group 1 and the third lens group 3 are fixedly installed on the housing, and the second lens group 2 is movably installed on the housing along the optical axis direction. Among them, the second lens group 2 is driven by an external force to move along the optical axis to perform moving focusing corresponding to the positions of the first lens group 1 and the third lens group 3, the imaging wavelength, and the imaging object distance, so that the imaging surface of the fixed-focus optical system remains clear after focusing. Moreover, the first lens group 1 has a positive optical power, the second lens group 2 has a negative optical power, and the third lens group 3 has a negative optical power. Through the reasonable setting of the three lens groups and the conditional limitation of the focal length ratio of the fixed-focus optical system and the focal lengths of each lens group, the fixed-focus optical system realizes an ultra-long focal length, reaching f500mm. The jitter of the picture caused by the lens due to external force can be corrected by adjusting the eccentricity of the lens in the XY direction, so as to improve the technical problem of poor resolution performance in extreme environments in the prior art.

[0044] It should be noted that the second lens group 2 can 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 hand, and no limitation is made here.

[0045] Specifically, in this embodiment, the first lens group 1 includes a first lens 11 with a positive optical power, a second lens 12 with a negative optical power, a third lens 13 with a positive optical power, and a fourth lens 14 with a negative optical power, which are arranged in sequence from the object side to the image side; 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 first lens group 1 and the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 satisfy the following conditions: 0.15 < f1 / f11 < 21, and -0.52 < f1 / f12 < -0.38, and 0.68 < f1 / f13 < 0.92, and -0.25 < f1 / f14 < -0.18.

[0046] More specifically, in this embodiment, the first lens 11 is a convex-concave spherical lens with a positive optical power, that is, the object side surface of the first lens 11 is a convex surface and the image side surface is a concave surface. The second lens 12 is a spherical lens with a negative optical power. The third lens 13 is a spherical lens with a positive optical power. The fourth lens 1413 is a convex-concave spherical lens with a negative optical power. And the optical power of the first lens 11 is 1104.21, the optical power of the second lens 12 is -445.23, the optical power of the third lens 13 is 251.43, and the optical power of the fourth lens 14 is -933.61.

[0047] Further, the first lens 11 and the second lens 12 are glued together to form a first glued lens group with a positive optical power. And the optical power of the first glued lens group is 706.4.

[0048] The third lens 13 and the fourth lens 14 are glued together to form a second glued lens group with a positive optical power. And the optical power of the second glued lens group is 270.38.

[0049] The first lens group 1 and the first glued lens group, the second glued lens group satisfy the following conditions: 0.24 < f1 / f1112 < 0.33, 0.63 < f1 / f1314 < 0.86; where f1 is the focal length of the first lens group 1, f1112 is the focal length of the first glued lens group, and f1314 is the focal length of the second glued lens group. In this way, the glued parts are reasonably used to enable the optical components to improve the image quality of the optical system, reduce the loss of light energy, increase the imaging clarity, protect the scale surface, and further optimize the processing process to meet the design requirements.

[0050] Specifically, the second lens group 2 includes a fifth lens 21 with a negative optical power, a sixth lens 22 with a positive optical power, and a seventh lens 23 with a negative optical power, which are arranged in sequence from the object side to the image side; moreover, the focal length of the fifth lens 21 is f21, the focal length of the sixth lens 22 is f22, the focal length of the seventh lens 23 is f23, and the second lens group 2 and the fifth lens 21, the sixth lens 22, and the seventh lens 23 satisfy the following conditions: -0.38 < f2 / f21 < -0.28, and -1.18 < f2 / f22 < -0.87, and 2.2 < f2 / f23 < 2.98.

[0051] More specifically, in this embodiment, the fifth lens 21 is a spherical lens with a positive optical power, the sixth lens 22 is a spherical lens with a positive optical power, and the seventh lens 23 is a spherical lens with a negative optical power. Preferably, the optical power of the fifth lens 21 is 416.43, the optical power of the sixth lens 22 is 132.78, and the optical power of the seventh lens 23 is -52.56.

[0052] Specifically, the third lens group 3 includes an eighth lens 31 with a positive optical power, a ninth lens 32 with a positive optical power, and a tenth lens 33 with a negative optical power, which are arranged in sequence from the object side to the image side; 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, and the third lens group 3 and the eighth lens 31, the ninth lens 32, and the tenth lens 33 satisfy the following conditions: 0.72 < f3 / f31 < 0.97, and 1.0 < f3 / f32 < 1.4, and -3.5 < f3 / f33 < -2.5.

[0053] More specifically, in this embodiment, the eighth lens 31 is a spherical lens with a negative optical power, the ninth lens 32 is a spherical lens with a negative optical power, and the tenth lens 33 is a spherical lens with a positive optical power. Preferably, the optical power of the eighth lens 31 is -413.27, the optical power of the ninth lens 32 is -286.87, and the optical power of the tenth lens 33 is 114.92.

[0054] Further, the eighth lens 31 and the ninth lens 32 are glued together to form a third glued lens group with a negative optical power. Moreover, the optical power of the first glued lens group is -82.81. The third glued lens group is movably arranged in the plane where it is located along the direction perpendicular to the optical axis. When the fixed-focus optical system shakes, the third glued lens group can correct the shake at the center of the picture through eccentricity, and can correct the picture shake caused by external force on the lens by adjusting the eccentricity of the lens in the XY direction, ensuring the resolution of the lens when working in an unstable environment.

[0055] The third lens group 3 and the third glued lens group satisfy the following condition: 3.5 < f3 / f3132 < 4.9; where f3 is the focal length of the third lens group 3, and f3132 is the focal length of the first glued lens group. The glued components are reasonably used to enable the optical components to improve the image quality of the optical system, reduce the loss of light energy, increase the imaging clarity, protect the scale surface, and further optimize the processing flow to meet the design requirements.

[0056] With such a setting, by reasonably distributing the optical power of the lenses, adjusting the glass shape and material combination, the chromatic aberration and secondary spectrum are effectively eliminated, and the spherical aberration, coma, astigmatism, etc. on each lens are compensated and offset from each other to achieve the effect of clear imaging, so as to achieve the optimal correction of high-order aberrations and chromatic aberration.

[0057] It can be understood that the surface of the photosensitive chip 5 facing the object side is the imaging surface.

[0058] Specifically, the fixed-focus optical system further includes an aperture 4, and the aperture 4 is located between the first lens group 1 and the second lens group 2; that is, the aperture 4 is located between the fourth lens 14 and the fifth lens 21. In this embodiment, the aperture 4 is an adjustable aperture, and the adjustable aperture can perform corresponding aperture scaling measures according to the change of the ambient light intensity.

[0059] Specifically, in this embodiment, the fixed-focus optical system further includes a filter ⑥, and the filter ⑥ is located between the third lens group 3 and the imaging surface. The filter ⑥ is used to filter unnecessary wavelength bands of light and stray light to reduce optical noise and reduce the difficulty for the subsequent optoelectronic module processing part. The filter ⑥ can also be used to adjust the color degree of the object image during the final imaging, thereby improving the imaging quality.

[0060] Specifically, the imaging surface can be understood as the surface of the photosensitive chip facing the object side, that is, it can be the surface of a camera element such as a CCD or a CMOS. It can be understood that the light carrying the information of the photographed object can sequentially pass through the first lens group 1, the aperture 4, the second lens group 2, the third lens group 3, the filter ⑥ and finally form an image on the imaging surface.

[0061] Specifically, in this embodiment, the refractive index, curvature radius, and thickness interval of the lens material are shown in the following table, where the units of radius and thickness are both millimeters (mm).

[0062] Table 1 Lens parameters

[0063]

[0064]

[0065] Specifically, considering the influence of temperature changes, lenses made of glass have the characteristics of high hardness, strong wear resistance and long service life. In addition, the chemical properties of all-glass lenses are stable, and they are not easily affected by thermal expansion and contraction to cause focus deviation, nor are they easily corroded. All-glass lenses can well resist the problem of lens deformation caused by heat and maintain the high precision of the lens for a long time. In this embodiment, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 21, the sixth lens 22, the seventh lens 23, the eighth lens 31, the ninth lens 32, and the tenth lens 33 are all glass spherical lenses, which can reduce the influence of temperature on the optical performance of the lens. Because the reflection of the spherical lens obeys the law of reflection of light, it converges or diverges the light, which reduces the cost while ensuring image quality and reliability, has low assembly sensitivity, and improves the yield rate of finished products.

[0066] Furthermore, in this embodiment, the surface shape of the lens satisfies the following conditions:

[0067]

[0068] Where c is the curvature corresponding to the radius, y is the radial coordinate (its unit is the same as the lens length unit), and k is the conic 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 oblate).

[0069] Figures 2 to 4 The longitudinal aberration diagram, field curvature diagram, and distortion diagram of the fixed-focus optical system are respectively displayed. S and T in the diagram represent the aberration corresponding to the sagittal image plane and the meridional image plane, respectively.

[0070] As can be seen from the above figures, the spherical aberration, field curvature and distortion of the fixed-focus optical system in this embodiment can all be well corrected.

[0071] In summary, the fixed-focus optical system described in the present invention adopts a "positive-negative-negative" three-group structure, in which the second lens group 2 can be movably set to prevent shaking, operate in unstable environments and ensure the image resolution of the lens; and each lens in the fixed-focus optical system is a glass spherical mirror, which fully guarantees good optical performance.

[0072] In addition, the present invention also provides a monitoring camera device, which includes the fixed-focus optical system described in the above technical solution. Since the monitoring camera device includes the fixed-focus optical system, the specific structure of the fixed-focus optical system refers to the above embodiment. Since the fixed-focus optical system of this monitoring camera device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0073] The above descriptions are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's description and drawings, or direct / indirect applications in other related technical fields, within the scope of the present invention are included in the patent protection scope of the present invention.

Claims

1. A fixed-focus optical system, characterized in that: The fixed-focus optical system has an object side and an image side that are oppositely arranged along the optical axis direction. The fixed-focus optical system includes a housing and a first lens group with a positive focal power, an aperture stop, a second lens group with a negative focal power, a third lens group with a negative focal power, and a photosensitive chip that are sequentially arranged in the housing from the object side to the image side. Among them, the first lens group and the third lens group are fixedly installed in the housing, and the second lens group is movably arranged along the extension direction of the optical axis; Among them, the focal length of the fixed-focus optical system is f, 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, and the fixed-focus optical system satisfies the following conditions: 2.2 < f / f1 < 3, and -4.4 < f / f2 < -3.2, and -1.8 < f / f3 < -1.2; The first lens group includes a first lens with a positive focal power, a second lens with a negative focal power, a third lens with a positive focal power, and a fourth lens with a negative focal power that are sequentially arranged from the object side to the image side; 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 first lens group and the first lens, the second lens, the third lens, and the fourth lens satisfy the following conditions: 0.15 < f1 / f11 < 21, and -0.52 < f1 / f12 < -0.38, and 0.68 < f1 / f13 < 0.92, and -0.25 < f1 / f14 < -0.18; The second lens group includes a fifth lens with a positive focal power, a sixth lens with a positive focal power, and a seventh lens with a negative focal power that are sequentially arranged from the object side to the image side; 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 the second lens group and the fifth lens, the sixth lens, and the seventh lens satisfy the following conditions: -0.38 < f2 / f21 < -0.28, and -1.18 < f2 / f22 < -0.87, and 2.2 < f2 / f23 < 2.98; The third lens group includes an eighth lens with a negative focal power, a ninth lens with a negative focal power, and a tenth lens with a positive focal power that are sequentially arranged from the object side to the image side; 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, and the third lens group and the eighth lens, the ninth lens, and the tenth lens satisfy the following conditions: ​ 2. The fixed-focus optical system according to claim 1, wherein: ​ ​ 3. The fixed-focus optical system according to claim 2, wherein: The optical power of the first cemented lens group formed by the first lens and the second lens is positive, the optical power of the second cemented lens group formed by the third lens and the fourth lens is positive, the focal length of the first cemented lens group is f1112, the focal length of the second cemented lens group is f1314, and the first lens group, the first cemented lens group, and the second cemented lens group satisfy the following conditions: 0.24 < f1 / f1112 < 0.33, and 0.63 < f1 / f1314 < 0.

86.

4. The fixed-focus optical system according to claim 1, wherein: The eighth lens and the ninth lens are cemented and connected to form a third cemented lens group, and the third cemented lens group is movably arranged in a direction perpendicular to the optical axis on the plane where it is located.

5. The fixed-focus optical system according to claim 4, wherein: The optical power of the third cemented lens group is negative, the focal length of the third cemented lens group is f3132, and the third lens group and the third cemented lens group satisfy the following conditions: 3.5 < f3 / f3132 < 4.

9.

6. The fixed-focus optical system according to claim 1, wherein: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are all glass spherical lenses.

7. A surveillance camera device, characterized in that: The monitoring camera device includes the fixed-focus optical system according to any one of claims 1 to 6.

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