Periscopic wide-angle lens and surveillance camera

Abstract

The application provides a periscopic wide-angle lens and a monitoring camera. The periscopic wide-angle lens comprises, in order from an object side to an image side, a first lens group, a first mirror group, a second lens group and a third lens group. A first diaphragm is arranged at one end of the first lens group towards the object side, and a second diaphragm is arranged between the second lens group and the third lens group. The periscopic wide-angle lens can optimize the structure of the periscopic wide-angle lens and improve the use quality of the monitoring camera.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical equipment, in particular to a periscopic wide-angle lens. The present application also relates to a monitoring camera provided with the periscopic wide-angle lens. BACKGROUND

[0002] In modern industrial production, especially in the metallurgical, energy conversion and glass manufacturing industries involving high temperature and extreme environment operation, the furnace as the core process equipment, the precise monitoring of the internal combustion condition is directly related to the production safety, energy efficiency improvement and product quality stability. Since the internal temperature of the furnace is extremely high, a high-temperature monitoring lens structure is needed to monitor the situation inside the furnace.

[0003] Such special needs have led to the birth of an elongated rod-shaped monitoring lens, which is designed to overcome the problem of narrow opening and limited space of the furnace, while ensuring that the lens tip can carry high-precision sensors to penetrate the internal furnace and capture key parameters such as flame shape, combustion efficiency and temperature distribution in real time.

[0004] However, due to its elongated shape, the field of view of such a lens is inevitably greatly limited. Most of the high-temperature furnace monitoring cameras on the market can only provide an effective field of view of about 60°. A single lens often cannot fully cover the complex space inside the furnace, especially the corners and deep areas of the furnace, which may become a blind area of monitoring, posing a hidden danger to safe production. In order to make up for this deficiency, production enterprises have to adopt a multi-lens layout strategy, by installing multiple sets of monitoring equipment to monitor the furnace from multiple angles and positions, which undoubtedly increases the system complexity and maintenance cost, and is not conducive to improving the use quality of the monitoring camera. SUMMARY

[0005] Therefore, the present application aims to provide a periscopic wide-angle lens to optimize the structure of the periscopic wide-angle lens and improve the use quality of the monitoring camera.

[0006] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0007] A periscopic wide-angle lens, comprising a first lens group, a first mirror group, a second lens group and a third lens group arranged in order from the object side to the image side;

[0008] Wherein, a first diaphragm is arranged at one end of the first lens group towards the object side, and a second diaphragm is arranged between the second lens group and the third lens group.

[0009] Further, the first lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged in order from the object side to the image side;

[0010] The first lens is sapphire window glass;

[0011] The second lens is a meniscus positive lens curved towards the first diaphragm;

[0012] The third lens is a meniscus positive lens curved towards the first diaphragm;

[0013] The fourth lens is a biconvex positive lens;

[0014] The fifth lens is a meniscus negative lens curved towards the first diaphragm;

[0015] The sixth lens is a biconvex positive lens.

[0016] Further, the first lens, the second lens, the third lens, the fourth lens and the fifth lens are made of heavy crown glass or lanthanum crown glass, and the sixth lens is made of heavy barium flint glass or lanthanum crown glass.

[0017] Further, the second lens group comprises a seventh lens, an eighth lens and a ninth lens;

[0018] The seventh lens is a biconvex lens;

[0019] The eighth lens is a negative lens with a convex object side and a concave image side;

[0020] The ninth lens is a biconvex lens;

[0021] The eighth lens and the ninth lens constitute a pair of doublet lenses.

[0022] Further, the seventh lens is made of heavy crown glass or lanthanum crown glass, the eighth lens is made of heavy barium flint glass, lanthanum crown glass or lanthanum flint glass, and the ninth lens is made of crown glass, light crown glass or heavy crown glass.

[0023] Further, the third lens group comprises a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens;

[0024] The tenth lens is a biconvex lens;

[0025] The eleventh lens is a negative lens with a convex object side and a concave image side;

[0026] The twelfth lens is a biconvex lens;

[0027] The thirteenth lens is a biconvex lens;

[0028] The fourteenth lens is a biconcave lens;

[0029] The eleventh lens and the twelfth lens constitute a pair of double cemented lenses, and the thirteenth lens and the fourteenth lens constitute a pair of cemented lenses.

[0030] Further, the tenth lens and the eleventh lens are made of heavy barium flint glass, lanthanum crown glass or lanthanum flint glass, the twelfth lens and the thirteenth lens are made of crown glass, light crown glass or heavy crown glass, and the fourteenth lens is made of heavy flint glass.

[0031] Further, the focal length of the lens is 3.5mm-6mm, the ratio of the focal length of the second lens group to the focal length of the lens is 40:1-50:1, the ratio of the third lens group to the focal length of the lens is 70:1-95:1, the relative aperture is 1 / 3.5-1 / 20, and the aperture range of the first diaphragm is 0.5mm-1.5mm.

[0032] Further, the second diaphragm is a variable diaphragm; and / or,

[0033] The first reflecting mirror group is a right-angle prism or a plane mirror.

[0034] Compared with the prior art, the present application has the following advantages:

[0035] The periscopic wide-angle lens can realize large field angle imaging through the lens optical structure composed of the first lens group, the second lens group, the third lens group, the first reflecting mirror group, the first diaphragm and the second diaphragm, and can be used for axial shooting of a high-temperature furnace through the periscopic lens structure and the reflection of the first lens group by the first reflecting mirror group, thereby helping to improve the use range and use quality of the periscopic wide-angle lens.

[0036] The first lens group performs first imaging on an object, and cooperates with each lens of the first lens group to bear a large field angle and preliminarily correct aberration, thereby helping to improve the imaging clarity and design implementation.

[0037] The second lens group performs second imaging on the object, and cooperates with each lens of the second lens group to correct the aberration of the first lens group, thereby helping to improve the imaging clarity and design implementation.

[0038] The third lens group performs third imaging on the object, and cooperates with each lens of the third lens group to correct the residual aberration of the second lens group, thereby helping to improve the imaging clarity and design implementation.

[0039] The lenses in the first lens group, the second lens group and the third lens group are made of materials with high transition temperature and low thermal expansion coefficient, thereby helping to improve the use effect of the first lens group in a high-temperature environment and design implementation.

[0040] The first diaphragm has a small aperture range, which reduces the heat and dust entering the lens and ensures the stability of the optical performance of the lens.

[0041] The second diaphragm is a variable diaphragm, which is used to adjust the aperture size of the second diaphragm and the amount of light entering the lens, so that the amount of light entering the lens is adjusted to an appropriate range, and the camera is prevented from being overexposed.

[0042] In addition, the present application also provides a monitoring camera, wherein the periscopic wide-angle lens is arranged in the monitoring camera.

[0043] The monitoring camera has the same beneficial effects as the periscopic wide-angle lens described above, and thus will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0044] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation of the present application. In the drawings:

[0045] Figure 1 A structural schematic diagram of the periscopic wide-angle lens according to the embodiments of the present application;

[0046] Figure 2 Optical resolution of the periscopic wide-angle lens according to the embodiments of the present application;

[0047] Figure 3 Vignetting of the periscopic wide-angle lens according to the embodiments of the present application;

[0048] Legend of reference signs:

[0049] 1, first lens group;

[0050] 100, first diaphragm; 101, first lens; 102, second lens; 103, third lens; 104, fourth lens; 105, fifth lens; 106, sixth lens;

[0051] 2, first mirror group;

[0052] 3, second lens group;

[0053] 301, seventh lens; 302, eighth lens; 303, ninth lens;

[0054] 4, third lens group;

[0055] 400, second diaphragm; 401, tenth lens; 402, eleventh lens; 403, twelfth lens; 404, thirteenth lens; 405, fourteenth lens. DETAILED DESCRIPTION

[0056] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0057] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0058] Embodiment one

[0059] The present embodiment relates to a periscopic wide-angle lens, to improve the use quality of the periscopic wide-angle lens by optimizing the lens structure.

[0060] Overall structure, the periscopic wide-angle lens in the present embodiment includes first mirror group 1, first mirror group 2, second mirror group 3 and third mirror group 4 arranged in order from object side to image side.

[0061] Among them, the first diaphragm 100 is arranged at the end of the first mirror group 1 towards the object side, and the second diaphragm 400 is arranged between the second mirror group 3 and the third mirror group 4.

[0062] As arranged above, the periscopic wide-angle lens in the present embodiment, through the lens optical structure composed of the first mirror group 1, the second mirror group 3, the third mirror group 4, the first mirror group 2, the first diaphragm 100 and the second diaphragm 400, can realize large field angle imaging, and through the periscopic lens structure, the first mirror group 2 is used to reflect the imaging of the first mirror group 1, so that the lens can be used for axial shooting of high-temperature furnace, which helps to improve the use range of the periscopic wide-angle lens and improve the use quality of the periscopic wide-angle lens.

[0063] Based on the overall introduction above, as an exemplary structure, the first mirror group 2 of the periscopic wide-angle lens in the present embodiment is a right-angle prism or a plane mirror, which may, for example, be a plane mirror arranged obliquely in the present embodiment, and only needs to satisfy that it can reflect the imaging of the first mirror group 1 to the second mirror group 3.

[0064] The second diaphragm 400 of the periscopic wide-angle lens in the present embodiment is a variable diaphragm, so that the second diaphragm 400 is a variable diaphragm, which is conducive to adjusting the aperture size of the second diaphragm 400 and adjusting the light amount to a suitable range to avoid overexposure of the camera.

[0065] It should be noted that when the periscopic wide-angle lens in the present embodiment is applied in the high-temperature furnace, the brightness of the flame in the high-temperature furnace will change, so by arranging the variable diaphragm, the light amount can be adjusted to a suitable range to avoid overexposure of the camera.

[0066] In order to have a larger field of view, the first lens group 1 of the periscopic wide-angle lens in the embodiment includes first lens 101, second lens 102, third lens 103 and fourth lens 104 arranged in order from the object side to the image side, the first lens 101 is sapphire window glass, the second lens 102 is a crescent-shaped positive lens bending towards the first diaphragm 100, the third lens 103 is a crescent-shaped positive lens bending towards the first diaphragm 100, the fourth lens 104 is a biconvex positive lens, the fifth lens 105 is a crescent-shaped negative lens bending towards the first diaphragm 100, and the sixth lens 106 is a biconvex positive lens. The first lens group 1 performs the first imaging on the object, and through the cooperation of the lenses of the first lens group 1, a larger field of view is achieved, and the aberration is preliminarily corrected, which is beneficial to improve the definition of imaging and helps the design implementation.

[0067] Specifically, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104 and the fifth lens 105 in the embodiment are made of heavy crown glass or lanthanum crown glass, and the sixth lens 106 is made of heavy barium flint glass or lanthanum crown glass. The grade of the heavy crown glass or lanthanum crown glass may be, for example, H-Zk3A, H-ZK7A, H-ZK9A, H-ZK6A, H-LAK3, H-LAK4L, and the grade of the heavy barium flint glass or lanthanum crown glass may be, for example, H-ZBAF1, H-ZBAF3, H-LAF2, H-LAF50B.

[0068] In order to improve the definition of imaging, the second lens group 3 in the embodiment includes seventh lens 301, eighth lens 302 and ninth lens 303, the seventh lens 301 is a biconvex lens, the eighth lens 302 is a negative lens with the object side convex and the image side concave, and the ninth lens 303 is a biconvex lens. The eighth lens 302 and the ninth lens 303 constitute a pair of doublet lenses, the second lens group 3 performs the second imaging on the object, and the aberration of the first lens group 1 is corrected through the cooperation of the lenses of the second lens group 3, which is beneficial to improve the definition of imaging and helps the design implementation.

[0069] Specifically, the seventh lens 301 of the second lens group 3 in the embodiment is made of heavy crown glass or lanthanum crown glass, the eighth lens 302 is made of heavy barium flint glass, lanthanum crown glass or lanthanum flint glass, and the ninth lens 303 is made of crown glass, light crown glass or heavy crown glass. The grade of the heavy crown glass or lanthanum crown glass may be, for example, H-Zk3A, H-ZK7A, H-ZK9A, H-ZK6A, H-LAK3, H-LAK4L.

[0070] In order to improve the clarity of imaging, the third lens group 4 in the embodiment includes a tenth lens 401, an eleventh lens 402, a twelfth lens 403, a thirteenth lens 404 and a fourteenth lens 405, the tenth lens 401 is a double convex lens, the eleventh lens 402 is a negative lens with a convex object side and a concave image side, the twelfth lens 403 is a double convex lens, the thirteenth lens 404 is a double convex lens, and the fourteenth lens 405 is a double concave lens, wherein the eleventh lens 402 and the twelfth lens 403 form a pair of double cemented lenses, the thirteenth lens 404 and the fourteenth lens 405 form a pair of cemented lenses, the third lens group 4 performs the third imaging on the object, and the residual aberration of the second lens group 3 is corrected through the cooperation of the lenses of the third lens group 4, which is beneficial to improve the clarity of imaging and helps the design and implementation.

[0071] Specifically, the tenth lens 401 and the eleventh lens 402 of the third lens group 4 in the embodiment are made of heavy barium flint glass, lanthanum crown glass or lanthanum flint glass, the twelfth lens 403 and the thirteenth lens 404 are made of crown glass, light crown glass or heavy crown glass, and the fourteenth lens 405 is made of heavy flint glass.

[0072] The periscopic wide-angle lens in the embodiment performs the first imaging on the object through the first lens group 1, undertakes a larger field of view angle through the cooperation of the lenses of the first lens group 1, and preliminarily corrects the aberration, which is beneficial to improve the clarity of imaging and helps the design and implementation. The second imaging on the object is performed through the second lens group 3, and the aberration of the first lens group 1 is corrected through the cooperation of the lenses of the second lens group 3, which is beneficial to improve the clarity of imaging and helps the design and implementation. The third imaging on the object is performed through the third lens group 4, and the residual aberration of the second lens group 3 is corrected through the cooperation of the lenses of the third lens group 4, which is beneficial to improve the clarity of imaging and helps the design and implementation.

[0073] The focal length range of the periscopic wide-angle lens in the embodiment is 3.5mm-6mm, for example, it can be 3.5mm, 4mm, 4.5mm, 5mm, etc., the ratio of the focal length of the second lens group 3 to the focal length of the lens is in the range of 40:1-50:1, for example, it can be 40:1, 45:1, etc., the ratio of the third lens group 4 to the focal length of the lens is in the range of 70:1-95:1, for example, it can be 75:1, 80:1, 90:1, etc., the relative aperture is in the range of 1 / 3.5-1 / 20, for example, it can be 1 / 4, 1 / 5, 1 / 6, 1 / 10, etc., the aperture range of the first diaphragm 100 is 0.5mm-1.5mm, for example, it can be 0.5mm, 1mm, 1.5mm, etc., so that the aperture range of the first diaphragm 100 is a small aperture, which is beneficial to reduce the heat and dust entering the lens and ensure the stability of the optical performance of the lens.

[0074] When the focal length of the periscopic wide-angle lens in the embodiment is 4mm, the maximum relative aperture is 1 / 4, the total field of view 2w=80°, the total length of the lens is 822mm, and the lens aperture is less than or equal to 22mm, the periscopic wide-angle lens in the embodiment is applicable to a 1 / 2.7 inch CMOS sensor with a resolution of 1920*1080. In order to meet the use requirements of the sensor, the optical resolution of the lens needs to reach 186lp / mm. In combination with FIG. 6, it can be seen that the optical resolution of the lens in the total field of view can reach more than 0.3 at a frequency of 1861p / mm. In combination with FIG. 7, it can be seen that the chromatic aberration of the lens in the embodiment is less than 1μm, and the lens has good color restoration. Figure 2 Figure 3

[0075] The optical parameters of the periscopic wide-angle lens in the embodiment are shown in Table 1.

[0076] Table 1. Optical parameters of the periscopic wide-angle lens in the embodiment

[0077]

[0078]

[0079] The periscopic wide-angle lens of the present application is applicable to the metallurgy, energy, glass melting and other industries that need to work in a high-temperature furnace and need to monitor the combustion conditions of the fuel in the furnace in real time to ensure safety and efficiency.

[0080] Embodiment two

[0081] The embodiment relates to a monitoring camera, wherein the periscopic wide-angle lens described in embodiment one is arranged in the monitoring camera.

[0082] The monitoring camera in the embodiment can work in a high-temperature furnace through the periscopic wide-angle lens in embodiment one, can clearly monitor the combustion conditions in the furnace, and is beneficial to improving the use quality of the monitoring camera.

[0083] The above only describes preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.​​

Claims

1. A periscopic wide-angle lens characterized in that: it comprises, in order from the object side to the image side, a first lens group (1), a first mirror group (2), a second lens group (3), and a third lens group (4); wherein a first diaphragm (100) is arranged at the end of the first lens group (1) toward the object side, and a second diaphragm (400) is arranged between the second lens group (3) and the third lens group (4); the first lens group (1) comprises, in order from the object side to the image side, a first lens (101), a second lens (102), a third lens (103), and a fourth lens (104), a fifth lens (105), and a sixth lens (106); the first lens (101) is a sapphire window glass; the second lens (102) is a meniscus positive lens bent toward the first diaphragm (100); the third lens (103) is a meniscus positive lens bent toward the first diaphragm (100); the fourth lens (104) is a biconvex positive lens; the fifth lens (105) is a meniscus negative lens bent toward the first diaphragm (100); the sixth lens (106) is a biconvex positive lens; the first lens (101), the second lens (102), the third lens (103), the fourth lens (104), and the fifth lens (105) are made of heavy crown glass or lanthanum crown glass, and the sixth lens (106) is made of heavy barium flint glass or lanthanum crown glass; the second lens group (3) comprises a seventh lens (301), an eighth lens (302), and a ninth lens (303); the seventh lens (301) is a biconvex lens; the eighth lens (302) is a negative lens with the object side convex and the image side concave; the ninth lens (303) is a biconvex lens; wherein the eighth lens (302) and the ninth lens (303) constitute a pair of double cemented lenses; the seventh lens (301) is made of heavy crown glass or lanthanum crown glass, the eighth lens (302) is made of heavy barium flint glass, lanthanum crown glass, or lanthanum flint glass, and the ninth lens (303) is made of crown glass, light crown glass, or heavy crown glass; the third lens group (4) comprises a tenth lens (401), an eleventh lens (402), a twelfth lens (403), a thirteenth lens (404), and a fourteenth lens (405); the tenth lens (401) is a biconvex lens; the eleventh lens (402) is a negative lens with the object side convex and the image side concave; the twelfth lens (403) is a biconvex lens; the thirteenth lens (404) is a biconvex lens; the fourteenth lens (405) is a biconcave lens; wherein the eleventh lens (402) and the twelfth lens (403) constitute a pair of double cemented lenses, and the thirteenth lens (404) and the fourteenth lens (405) constitute a pair of cemented lenses. The tenth mirror (401) and the eleventh mirror (402) are made of heavy barium flint glass, lanthanum crown glass or lanthanum flint glass, the twelfth mirror (403) and the thirteenth mirror (404) are made of crown glass, light crown glass or heavy crown glass, and the fourteenth mirror (405) is made of heavy flint glass.

2. The periscopic wide-angle lens according to claim 1, wherein: a focal length of the lens is 3.5-6 mm, a ratio of a focal length of the second lens group (3) to the focal length of the lens is 40:1-50:1, a ratio of the third lens group (4) to the focal length of the lens is 70:1-95:1, a relative aperture is 1 / 3.5-1 / 20, and an aperture range of the first diaphragm (100) is 0.5-1.5 mm.

3. The periscopic wide-angle lens according to claim 2, wherein: the second diaphragm (400) is a variable diaphragm; and / or, the first mirror group (2) is a right-angle prism or a plane mirror.

4. A surveillance camera, wherein: the periscopic wide-angle lens according to any one of claims 1-3 is used in the surveillance camera. ​ ​ ​ ​

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