Infrared confocal lens

Abstract

The utility model relates to the technical field of optical imaging, in particular to an infrared confocal lens, which comprises optical lens groups sequentially arranged from an object space to an image space, and the optical lens groups are respectively a first lens group with positive refractive power, a second lens group with positive refractive power and an optical filter. The ratio of the focal distance of the optical lens group to the image height is 0.4-2, and the ratio of the focal distance of the optical lens group to the focal distance of the first lens group is 0-1.5; the ratio of the focal distance of the optical lens group to the focal distance of the second lens group is between 0 and 1.9. According to the infrared confocal lens optical system, the focal distance, the refractive index and the Abbe number of the first lens group and the second lens group are limited, so that the field curvature, the aberration and the eccentric sensitivity of the infrared confocal lens optical system are further improved; therefore, the optical performance of the infrared confocal lens optical system is ensured, and the infrared confocal lens optical system has the characteristics of large aperture, high resolution, small chromatic aberration and infrared confocal.

Description

Technical Field

[0001] This utility model relates to the technical field of optical imaging, specifically to an infrared confocal lens. Background Technology

[0002] With the rapid development of optical camera lenses, optical imaging lenses have also seen rapid advancements in recent years, finding widespread application in various fields such as smartphones, tablets, video conferencing, vehicle monitoring, security monitoring, and intelligent transportation systems. Therefore, day / night confocal lenses achieve the same clarity during both day and night, which is particularly advantageous for nighttime monitoring. Most road monitoring lenses on the market lack day / night confocal functionality and instead use filters of varying thicknesses to achieve this.

[0003] However, most infrared confocal lenses currently used in automotive and security applications generally suffer from large infrared visible defocus, resulting in reduced sharpness.

[0004] Based on this, the present invention designs an infrared confocal lens to solve the above problems. Utility Model Content

[0005] To achieve the above objectives, this utility model provides the following technical solution: an infrared confocal lens, comprising optical lens groups arranged sequentially from the object side to the image side, wherein the optical lens groups are a first lens group with positive refractive power, a second lens group with positive refractive power, and a filter; the first lens group comprises, from the object side to the image side, a first lens with negative refractive power and a second lens with positive refractive power; the second lens group comprises, from the object side to the image side, a third lens with positive refractive power, a fourth lens with negative refractive power, a fifth lens with positive refractive power, a sixth lens with positive refractive power, a seventh lens with negative refractive power, an eighth lens with positive refractive power, a ninth lens with positive refractive power, and a tenth lens with negative refractive power; the ratio of the focal distance to the image height of the optical lens group is between 0.4 and 2, the ratio of the focal distance of the optical lens group to the focal distance of the first lens group is between 0 and 1.5, and the ratio of the focal distance of the optical lens group to the focal distance of the second lens group is between 0 and 1.9.

[0006] Preferably, the focal distance ratio between the first lens and the first lens group is between 0 and 2; the focal distance ratio between the second lens and the first lens group is between 0 and 1.9; the focal distance ratio between the third lens and the second lens group is between 0 and 19; the focal distance ratio between the fourth lens and the second lens group is between 0 and 1.3; the focal distance ratio between the fifth lens and the second lens group is between 0 and 1.5; the focal distance ratio between the sixth lens and the second lens group is between 0 and 1.9; the focal distance ratio between the seventh lens and the second lens group is between 0 and 1.5; the focal distance ratio between the eighth lens and the second lens group is between 0 and 1.6; the focal distance ratio between the ninth lens and the second lens group is between 0 and 4.1; and the focal distance ratio between the tenth lens and the second lens group is between 0 and 2.5.

[0007] Preferably, the refractive index of the first lens is less than 1.85, the refractive index of the second lens is greater than 1.75, the refractive index of the third lens is greater than 1.65, the refractive index of the fourth lens is greater than 1.75, the refractive index of the fifth lens is less than 1.7, the refractive index of the sixth lens is less than 1.7, the refractive index of the seventh lens is greater than 1.45, the refractive index of the eighth lens is greater than 1.65, the refractive index of the ninth lens is less than 1.80, and the refractive index of the tenth lens is less than 1.85.

[0008] Preferably, the Abbe number of the first lens is greater than 25, the Abbe number of the second lens is less than 50, the Abbe number of the third lens is less than 80, the Abbe number of the fourth lens is less than 50, the Abbe number of the fifth lens is greater than 25, the Abbe number of the sixth lens is greater than 25, the Abbe number of the seventh lens is less than 80, the Abbe number of the eighth lens is less than 80, the Abbe number of the ninth lens is less than 80, and the Abbe number of the tenth lens is greater than 25.

[0009] In summary, this application has the following beneficial technical effects: by setting up a first lens group and a second lens group, both the first and second lens groups have positive refractive power, resulting in excellent optical performance of the infrared confocal lens optical system. By limiting the focal distance, refractive index, and Abbe number of the first and second lens groups, the field curvature, aberration, and eccentricity sensitivity of the infrared confocal lens optical system are further improved, thereby ensuring the optical performance of the infrared confocal lens optical system. This results in the infrared confocal lens optical system having the characteristics of large aperture, high resolution, small chromatic aberration, and infrared confocality. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a structural diagram of Embodiment 1 of the present invention;

[0012] Figure 2 This is a defocus curve of the visible light 435-650nm of Embodiment 1 of the present invention;

[0013] Figure 3 This is a defocus curve of infrared light at 870-830nm according to Embodiment 1 of the present invention;

[0014] Figure 4 This is a field curvature and distortion diagram of the visible light 435-650nm of Embodiment 1 of the present invention;

[0015] Figure 5 This is a field curvature and distortion diagram of the visible light 870-830nm of Embodiment 1 of the present invention;

[0016] Figure 6 This is a structural diagram of Embodiment 2 of the present invention;

[0017] Figure 7 This is a defocus curve of the visible light 435-650nm in Embodiment 2 of the present invention;

[0018] Figure 8 This is a defocus curve of infrared light at 870-830nm in Embodiment 2 of the present invention;

[0019] Figure 9 This is a field curvature and distortion diagram of the visible light range of 435-650nm in Embodiment 2 of the present invention;

[0020] Figure 10 This is a field curvature and distortion diagram of the visible light 870-830nm of Embodiment 2 of the present invention.

[0021] The attached diagram lists the components represented by each number as follows:

[0022] 711. First lens; 712. Second lens; 721. Third lens; 722. Fourth lens; 723. Fifth lens; 724. Sixth lens; 725. Seventh lens; 726. Eighth lens; 727. Ninth lens; 728. Tenth lens. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0024] The following is in conjunction with the appendix Figure 1-10 This application will be further described in detail.

[0025] Referring to Figures 1-5 , an infrared confocal lens includes an optical lens group arranged in sequence from the object side to the image side. The optical lens group includes a first lens group with positive refractive power, a second lens group with positive refractive power, and a filter; the optical lenses of the first lens group arranged in sequence from the object side to the image side are: a first lens 711 with negative refractive power and a second lens 712 with positive refractive power; the optical lenses of the second lens group arranged in sequence from the object side to the image side are: a third lens 721 with positive refractive power, a fourth lens 722 with negative refractive power, a fifth lens 723 with positive refractive power, a sixth lens 724 with positive refractive power, a seventh lens 725 with negative refractive power, an eighth lens 726 with positive refractive power, a ninth lens 727 with positive refractive power, and a tenth lens 728 with negative refractive power;

[0026] Referring to Figures 1-5 , the focal length of the optical lens group is represented by f, and the image height is represented by IH. The ratio of the two satisfies 0.4 < f / IH < 2; the focal length of the first lens group is represented by f1, and the focal length of the second lens group is represented by f2. The ratio of the focal length of the optical lens group to the focal length of the first lens group satisfies 0 < |f / f1| < 1.5; the ratio of the focal length of the optical lens group to the focal length of the second lens group satisfies 0 < |f / f2| < 1.9.

[0027] Referring to Figures 1-5 , the focal length of the first lens 711 is represented by f11, the focal length of the second lens 712 is represented by f12, the focal length of the third lens 721 is represented by f21, the focal length of the fourth lens 722 is represented by f22, the focal length of the fifth lens 723 is represented by f23, the focal length of the sixth lens 724 is represented by f24, the focal length of the seventh lens 725 is represented by f25, the focal length of the eighth lens 726 is represented by f26, the focal length of the ninth lens 727 is represented by f27, and the focal length of the tenth lens 728 is represented by f28; the focal lengths of each lens satisfy: 0 < |f11 / f1| < 2.0, 0 < |f12 / f1| < 1.9, 0 < |f21 / f2| < 1.9, 0 < |f22 / f2| < 1.3, 0 < |f23 / f2| < 1.5, 0 < |f24 / f2| < 1.9, 0 < |f25 / f2| < 1.5, 0 < |f26 / f2| < 1.6, 0 < |f27 / f2| < 4.1, 0 < |f28 / f2| < 2.5.

[0028] Referring to Figures 1-5The refractive index of the first lens 711 is denoted by N11, the refractive index of the second lens 712 is denoted by N12, the refractive index of the third lens 721 is denoted by N21, the refractive index of the fourth lens 722 is denoted by N22, the refractive index of the fifth lens 723 is denoted by N23, the refractive index of the sixth lens 724 is denoted by N24, the refractive index of the seventh lens 725 is denoted by N25, the refractive index of the eighth lens 726 is denoted by N26, the refractive index of the ninth lens 727 is denoted by N27, and the refractive index of the tenth lens 728 is denoted by N28; the refractive indices of each lens satisfy the following:

[0029] N11<1.85, N12>1.75, N21>1.65, N22>1.75, N23<1.70, N24<1.70, N25

[0030] >1.45, N26>1.65, N27<1.80, N28<1.85.

[0031] Reference Figures 1-5 The Abbe number of the first lens 711 is denoted by V11, the Abbe number of the second lens 712 by V12, the Abbe number of the third lens 721 by V21, the Abbe number of the fourth lens 722 by V22, the Abbe number of the fifth lens 723 by V23, the Abbe number of the sixth lens 724 by V24, the Abbe number of the seventh lens 725 by V25, the Abbe number of the eighth lens 726 by V26, the Abbe number of the ninth lens 727 by V27, and the Abbe number of the tenth lens 728 by V28; the Abbe number of each lens satisfies:

[0032] V11>25, V12<50, V21<80, V22<50, V23>25, V24>25, V25<80, V26<80, V27<80, V28>25.

[0033] Reference Figures 1-5 In this embodiment: the focal length f11 of the first lens 711 is -13.85mm, the refractive index N11 is 1.49, and the Abbe number V11 is 70.4.

[0034] The second lens 712 has a focal length f12 of 13.63 mm, a refractive index N12 of 2.02, and an Abbe number V12 of 19.3.

[0035] The third lens 721 has a focal length f21 of 10.57 mm, a refractive index N21 of 1.80, and an Abbe number V21 of 39.6.

[0036] The fourth lens 722 has a focal length f22 of -4.04mm, a refractive index N22 of 1.81, and an Abbe number V22 of 22.7.

[0037] The fifth lens 723 has a focal length f23 of 6.31 mm, a refractive index N23 of 1.50, and an Abbe number V23 of 81.6.

[0038] The sixth lens 724 has a focal length f24 of 8.23 ​​mm, a refractive index N24 of 1.44, and an Abbe number V24 of 94.5.

[0039] The seventh lens, 725, has a focal length (f25) of -2.91 mm, a refractive index (N25) of 1.75, and an Abbe number (V25) of 25.0.

[0040] The eighth lens 726 has a focal length f26 of 3.77 mm, a refractive index N26 of 1.92, and an Abbe number V26 of 24.0.

[0041] The ninth lens 727 has a focal length (f27) of 11.39 mm, a refractive index (N27) of 1.72, and an Abbe number (V27) of 43.7.

[0042] The tenth lens 728 has a focal length f28 of -6.28mm, a refractive index N28 of 1.75, and an Abbe number V28 of 37.5.

[0043] Reference Figures 1-5 It can be seen that the infrared confocal lens in this embodiment can produce images of better quality when the aberrations are small.

[0044] Figure 2 and Figure 3 The comparison shows that the infrared defocusing amount is controlled within 3µm.

[0045] The implementation principle of this embodiment is as follows: by setting the first lens group and the second lens group, the first lens group has positive refractive power and the second lens group has positive refractive power, so that the infrared confocal lens optical system has good optical performance. By limiting the focal distance, refractive index and Abbe number of the first lens group and the second lens group, the field curvature, aberration and eccentricity sensitivity of the infrared confocal lens optical system are further improved, thereby ensuring the optical performance of the infrared confocal lens optical system, so that the infrared confocal lens optical system has the characteristics of large aperture, high resolution, small chromatic aberration and infrared confocal.

[0046] Reference Figures 6-10 In Example 2, the focal length f11 of the first lens 711 is -9.03mm, the refractive index N11 is 1.69, and the Abbe number V11 is 31.1.

[0047] The second lens 712 has a focal length f12 of 10.03 mm, a refractive index N12 of 1.92, and an Abbe number V12 of 20.9.

[0048] The third lens 721 has a focal length f21 of 19.52 mm, a refractive index N21 of 1.78, and an Abbe number V21 of 37.1.

[0049] The fourth lens 722 has a focal length f22 of -4.55mm, a refractive index N22 of 1.92, and an Abbe number V22 of 24.0;

[0050] The fifth lens 723 has a focal length f23 of 8.95mm, a refractive index N23 of 1.44, and an Abbe number V23 of 95.1;

[0051] The sixth lens 724 has a focal length f24 of 6.70 mm, a refractive index N24 of 1.50, and an Abbe number V24 of 81.6.

[0052] The seventh lens 725 has a focal length f25 of -3.92mm, a refractive index N25 of 1.58, and an Abbe number V25 of 40.9.

[0053] The eighth lens 726 has a focal length f26 of 4.53 mm, a refractive index N26 of 1.80, and an Abbe number V26 of 46.6;

[0054] The ninth lens 727 has a focal length f27 of 24.84 mm, a refractive index N27 of 1.49, and an Abbe number V27 of 70.4;

[0055] The tenth lens 728 has a focal length f28 of -9.29mm, a refractive index N28 of 1.49, and an Abbe number V28 of 70.4.

[0056] Reference Figures 7-10 The infrared confocal lens in this second embodiment can produce images of better quality when the aberration is relatively small.

[0057] Figure 7 and Figure 8 The comparison shows that the infrared defocusing amount is controlled within 3µm.

[0058] The implementation principle of this embodiment is as follows: by setting the first lens group and the second lens group, the first lens group 711 and the second lens group are made to have positive refractive power, so that the infrared confocal lens optical system has good optical performance. By limiting the focal distance, refractive index and Abbe number of the first lens group and the second lens group, the field curvature, aberration and eccentricity sensitivity of the infrared confocal lens optical system are further improved, thereby ensuring the optical performance of the infrared confocal lens optical system. This makes the infrared confocal lens optical system have the characteristics of large aperture, high resolution, small chromatic aberration and infrared confocality.

[0059] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0060] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0061] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An infrared confocal lens, characterized in that: The system includes an optical lens group arranged sequentially from the object side to the image side. The optical lens group consists of a first lens group with positive refractive power, a second lens group with positive refractive power, and a filter. The first lens group consists of the following optical lenses arranged sequentially from the object side to the image side: a first lens (711) with negative refractive power and a second lens (712) with positive refractive power. The second lens group consists of the following optical lenses arranged sequentially from the object side to the image side: a third lens (721) with positive refractive power, a fourth lens (722) with negative refractive power, a fifth lens (723) with positive refractive power, a sixth lens (724) with positive refractive power, a seventh lens (725) with negative refractive power, an eighth lens (726) with positive refractive power, a ninth lens (727) with positive refractive power, and a tenth lens (728) with negative refractive power. The ratio of the focal distance to the image height of the optical lens group is between 0.4 and 2, and the ratio of the focal distance of the optical lens group to the focal distance of the first lens group is between 0 and 1.

5. The ratio of the focal distance of the optical lens group to the focal distance of the second lens group is between 0 and 1.

9.

2. An infrared confocal lens according to claim 1, characterized in that: The focal distance ratio between the first lens (711) and the first lens group is between 0 and 2; the focal distance ratio between the second lens (712) and the first lens group is between 0 and 1.9; the focal distance ratio between the third lens (721) and the second lens group is between 0 and 19; the focal distance ratio between the fourth lens (722) and the second lens group is between 0 and 1.3; the focal distance ratio between the fifth lens (723) and the second lens group is between 0 and 1.5; the focal distance ratio between the sixth lens (724) and the second lens group is between 0 and 1.9; the focal distance ratio between the seventh lens (725) and the second lens group is between 0 and 1.5; the focal distance ratio between the eighth lens (726) and the second lens group is between 0 and 1.6; the focal distance ratio between the ninth lens (727) and the second lens group is between 0 and 4.1; and the focal distance ratio between the tenth lens (728) and the second lens group is between 0 and 2.

5.

3. An infrared confocal lens according to claim 2, characterized in that: The refractive index of the first lens (711) is less than 1.85, the refractive index of the second lens (712) is greater than 1.75, the refractive index of the third lens (721) is greater than 1.65, the refractive index of the fourth lens (722) is greater than 1.75, the refractive index of the fifth lens (723) is less than 1.7, the refractive index of the sixth lens (724) is less than 1.7, the refractive index of the seventh lens (725) is greater than 1.45, the refractive index of the eighth lens (726) is greater than 1.65, the refractive index of the ninth lens (727) is less than 1.80, and the refractive index of the tenth lens (728) is less than 1.

85.

4. An infrared confocal lens according to claim 3, characterized in that: The Abbe number of the first lens (711) is greater than 25, the Abbe number of the second lens (712) is less than 50, the Abbe number of the third lens (721) is less than 80, the Abbe number of the fourth lens (722) is less than 50, the Abbe number of the fifth lens (723) is greater than 25, the Abbe number of the sixth lens (724) is greater than 25, the Abbe number of the seventh lens (725) is less than 80, the Abbe number of the eighth lens (726) is less than 80, the Abbe number of the ninth lens (727) is less than 80, and the Abbe number of the tenth lens (728) is greater than 25.

Images