A telephoto infrared synchronous imaging lens

Abstract

The present invention relates to a telephoto infrared synchronous imaging lens, which includes a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), an aperture, a sixth lens (L6), a seventh lens (L7), an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11) and a twelfth lens (L12) in sequence from the object side to the image side along the optical axis; the first lens (L1), the second lens (L2), the fifth lens (L5), the sixth lens (L6) and the eighth lens (L8) are positive focal length lenses; the third lens (L3), the fourth lens (L4) and the seventh lens (L7) are negative focal length lenses. The telephoto infrared synchronous imaging lens of the present invention can realize the confocal of visible light and infrared light, and has the superior performance of large aperture (FNO≤1.6) and large target surface (half image height IH≥7.8mm), and is not out of focus in the temperature range of ‑40°C to +85°C.

Description

Technical Field

[0001] The invention relates to the technical field of optical system and device design, and in particular to a telephoto infrared synchronous imaging lens. Background Art

[0002] Intelligent traffic monitoring lenses are high-end optical devices for application scenarios and are crucial to the establishment of traffic safety systems. Most existing intelligent traffic monitoring lenses can only image the visible spectrum, and at night they need to be equipped with fill-in lighting equipment to work. If the fill-in lighting equipment is too bright, it can easily cause dizziness in the driver's eyes. Summary of the invention

[0003] The purpose of the present invention is to solve the above problems and provide a telephoto infrared synchronous imaging lens to solve the problem that the existing lens cannot achieve confocality of the visible spectrum and the infrared spectrum.

[0004] To achieve the above-mentioned object of the present invention, the present invention provides a telephoto infrared synchronous imaging lens, which includes, from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, an aperture, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens;

[0005] The first lens, the second lens, the fifth lens, the sixth lens and the eighth lens are positive power lenses;

[0006] The third lens, the fourth lens and the seventh lens are negative power lenses.

[0007] According to one aspect of the present invention, along the direction from the object side to the image side, the first lens and the second lens are convex-concave lenses, and the third lens is a convex-concave lens, a concave-concave lens or a plano-concave lens.

[0008] According to one aspect of the present invention, the fourth lens and the seventh lens are concave-concave lenses, and the fifth lens, the sixth lens and the eighth lens are convex-convex lenses.

[0009] According to one aspect of the present invention, the second lens and the third lens are arranged as a single lens or form a doublet lens.

[0010] According to one aspect of the present invention, the fourth lens and the fifth lens form a doublet lens.

[0011] According to one aspect of the present invention, the sixth lens, the seventh lens and the eighth lens form a triplet lens.

[0012] According to one aspect of the present invention, the ninth lens and the tenth lens form a doublet lens.

[0013] According to one aspect of the present invention, the eleventh lens and the twelfth lens form a doublet lens.

[0014] According to one aspect of the present invention, the refractive index Nd4 and the Abbe number Vd4 of the fourth lens satisfy the relationship: 1.60≤Nd4≤1.75, 29.00≤Vd4≤34.00.

[0015] According to one aspect of the present invention, the refractive index Nd5 and the Abbe number Vd5 of the fifth lens satisfy the relationship: 1.75≤Nd5≤1.85, 22.00≤Vd4≤26.00.

[0016] According to one aspect of the present invention, the refractive index Nd6 and the Abbe number Vd6 of the sixth lens satisfy the relationship: 1.45≤Nd6≤1.65, 55.00≤Vd6≤82.00.

[0017] According to one aspect of the present invention, the refractive index Nd7 and the Abbe number Vd7 of the seventh lens satisfy the relationship: 1.60≤Nd7≤1.80, 29.00≤Vd7≤32.50.

[0018] According to one aspect of the present invention, the refractive index Nd8 and the Abbe number Vd8 of the eighth lens satisfy the relationship: 1.45≤Nd8≤1.65, 55.00≤Vd8≤82.00.

[0019] According to one aspect of the present invention, the refractive index Nd9 and the Abbe number Vd9 of the ninth lens satisfy the relationship: 1.55≤Nd9≤1.65, 35.00≤Vd9≤38.50.

[0020] According to one aspect of the present invention, the refractive index Nd10 and the Abbe number Vd10 of the tenth lens satisfy the relationship: 1.85≤Nd10≤2.05, 28.00≤Vd10≤36.50.

[0021] According to one aspect of the present invention, the half image height IH of the telephoto infrared synchronous imaging lens and the effective focal length EFL of the telephoto infrared synchronous imaging lens satisfy the relationship: 0.13≤IH / EFL≤0.20.

[0022] According to one aspect of the present invention, the relationship is satisfied: 1.70≤TTL / EFL≤2.00;

[0023] The TTL represents the on-axis distance from the object side surface of the first lens to the target surface, and the EFL represents the effective focal length of the telephoto infrared synchronous imaging lens.

[0024] The telephoto infrared synchronous imaging lens of the present invention reasonably configures positive focal length and negative focal length lenses at different positions, which can receive incident light at a certain angle, ensure that the light obtains a sufficient image height when reaching the image plane, and avoid large-angle refraction of the incident light when passing through each optical surface, so that the light travels smoothly, which is conducive to correcting aberrations and reducing the system tolerance sensitivity.

[0025] The invented telephoto infrared synchronous imaging lens sets the above-mentioned specific shape of lens at a specific position, which ensures that the lens can meet certain field of view angle and image height requirements, while effectively controlling optical distortion to achieve low-distortion imaging effects. It can also make the light trend smooth, which is conducive to correcting aberrations and reducing system tolerance sensitivity.

[0026] The telephoto infrared synchronous imaging lens of the present invention is reasonably designed to use double or triple cemented lenses, which is beneficial to correcting the chromatic aberration of the visible spectrum of the lens, ensuring the imaging quality and improving the resolution performance; achieving the confocality of visible light and infrared light to ensure that the resolution requirements of visible light and infrared light can be taken into account at the same time; and is also beneficial to reducing tolerance sensitivity and improving production yield.

[0027] The telephoto infrared synchronous imaging lens of the present invention can realize the confocality of visible light and infrared light, and does not need to set up additional fill-light equipment for nighttime operation. At the same time, it has the superior performance of large aperture (FNO≤1.6) and large target surface (half-image height IH≥7.8mm), can obtain high-definition imaging pictures for both visible spectrum and infrared spectrum, and has a temperature compensation function, and is not out of focus within the temperature range of -40°C to +85°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram showing the structure of a telephoto infrared synchronous imaging lens according to Embodiment 1 of the present invention;

[0029] Figure 2 Schematically showing a visible light MTF diagram of a telephoto infrared synchronous imaging lens according to Embodiment 1 of the present invention;

[0030] Figure 3 The infrared light Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Embodiment 1 of the present invention is schematically shown;

[0031] Figure 4 The Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Example 1 of the present invention at -40°C is schematically shown;

[0032] Figure 5 The Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Example 1 of the present invention at 85° C. is schematically shown;

[0033] Figure 6 A schematic diagram showing the structure of a telephoto infrared synchronous imaging lens according to Embodiment 2 of the present invention;

[0034] Figure 7 Schematically showing a visible light MTF diagram of a telephoto infrared synchronous imaging lens according to Embodiment 2 of the present invention;

[0035] Figure 8 The infrared light Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Embodiment 2 of the present invention is schematically shown;

[0036] Fig. 9 The Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Example 2 of the present invention at -40°C is schematically shown;

[0037] Fig.10 The Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Example 2 of the present invention at 85° C. is schematically shown;

[0038] Fig.11 A schematic diagram showing the structure of a telephoto infrared synchronous imaging lens according to Embodiment 3 of the present invention;

[0039] Fig.12 Schematically showing a visible light MTF diagram of a telephoto infrared synchronous imaging lens according to Embodiment 3 of the present invention;

[0040] Fig.13 The infrared light Through-Focus-MTF diagram of the telephoto infrared synchronous imaging lens according to Embodiment 3 of the present invention is schematically shown;

[0041] Fig.14 The Through-Focus-MTF diagram of the telephoto infrared synchronous imaging lens according to Example 3 of the present invention at -40°C is schematically shown;

[0042] Fig.15 The Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Example 3 of the present invention at 85° C. is schematically shown;

[0043] Fig.16 A schematic diagram showing the structure of a telephoto infrared synchronous imaging lens according to Embodiment 4 of the present invention;

[0044] Fig.17 Schematically showing a visible light MTF diagram of a telephoto infrared synchronous imaging lens according to Embodiment 4 of the present invention;

[0045] Fig.18The infrared light Through-Focus-MTF diagram of the telephoto infrared synchronous imaging lens according to Embodiment 4 of the present invention is schematically shown;

[0046] Fig.19 The Through-Focus-MTF diagram of the telephoto infrared synchronous imaging lens according to Example 4 of the present invention at -40°C is schematically shown;

[0047] Fig. 20 The Through-Focus-MTF diagram of the long-focus infrared synchronous imaging lens according to Example 4 of the present invention at 85° C. is schematically shown. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0050] Reference Figure 1 As shown, the present invention provides a telephoto infrared synchronous imaging lens, which includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, an aperture, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11 and a twelfth lens L12.

[0051] In the long-focus infrared synchronous imaging lens of the present invention, the first lens L1, the second lens L2, the fifth lens L5, the sixth lens L6 and the eighth lens L8 are positive focal length lenses, and the third lens L3, the fourth lens L4 and the seventh lens L7 are negative focal length lenses.

[0052] The telephoto infrared synchronous imaging lens of the present invention reasonably configures positive focal length and negative focal length lenses at different positions, which can receive incident light at a certain angle, ensure that the light obtains a sufficient image height when reaching the image plane, and avoid large-angle refraction of the incident light when passing through each optical surface, so that the light travels smoothly, which is conducive to correcting aberrations and reducing the system tolerance sensitivity.

[0053] In the telephoto infrared synchronous imaging lens of the present invention, along the direction from the object side to the image side, the first lens L1 and the second lens L2 are convex-concave lenses, and the third lens L3 is a convex-concave lens, a concave-concave lens or a plano-concave lens. The fourth lens L4 and the seventh lens L7 are concave-concave lenses, and the fifth lens L5, the sixth lens L6 and the eighth lens L8 are convex-convex lenses. In the telephoto infrared synchronous imaging lens of the present invention, the lenses of the above-mentioned specific shapes are arranged at specific positions, which ensures that the lens can meet certain field of view angles and image height requirements, and effectively controls optical distortion to achieve low-distortion imaging effects. It can also make the light trend smooth, which is conducive to correcting aberrations and reducing system tolerance sensitivity.

[0054] In the telephoto infrared synchronous imaging lens of the present invention, the second lens L2 and the third lens L3 are arranged as separate lenses or form a doublet lens. The fourth lens L4 and the fifth lens L5 form a doublet lens. The sixth lens L6, the seventh lens L7 and the eighth lens L8 form a triplet lens. The ninth lens L9 and the tenth lens L10 form a doublet lens. The eleventh lens L11 and the twelfth lens L12 form a doublet lens.

[0055] The telephoto infrared synchronous imaging lens of the present invention is reasonably designed to use double or triple cemented lenses, which is beneficial to correcting the chromatic aberration of the visible spectrum of the lens, ensuring the imaging quality and improving the resolution performance; achieving the confocality of visible light and infrared light to ensure that the resolution requirements of visible light and infrared light can be taken into account at the same time; and is also beneficial to reducing tolerance sensitivity and improving production yield.

[0056] In the telephoto infrared synchronous imaging lens of the present invention, the refractive index Nd4 and the Abbe number Vd4 of the fourth lens L4 satisfy the relationship: 1.60≤Nd4≤1.75, 29.00≤Vd4≤34.00. The refractive index Nd5 and the Abbe number Vd5 of the fifth lens L5 satisfy the relationship: 1.75≤Nd5≤1.85, 22.00≤Vd4≤26.00. Meeting the above setting range is conducive to correcting the aberration of the lens of the present invention and ensuring the resolution performance.

[0057] In the telephoto infrared synchronous imaging lens of the present invention, the refractive index Nd6 and the Abbe number Vd6 of the sixth lens L6 satisfy the relationship: 1.45≤Nd6≤1.65, 55.00≤Vd6≤82.00. Such a setting is conducive to correcting the chromatic aberration of the telephoto infrared synchronous imaging lens and ensuring the resolution performance. At the same time, it can maintain the stability of the effective focal length of the lens in different temperature environments, realize the automatic temperature compensation function, and ensure the imaging quality in different temperature environments.

[0058] In the telephoto infrared synchronous imaging lens of the present invention, the refractive index Nd7 and the Abbe number Vd7 of the seventh lens L7 satisfy the relationship: 1.60≤Nd7≤1.80, 29.00≤Vd7≤32.50. Such a setting is conducive to correcting the aberration of the lens of the present invention and ensuring the resolution performance.

[0059] In the telephoto infrared synchronous imaging lens of the present invention, the refractive index Nd8 and the Abbe number Vd8 of the eighth lens L8 satisfy the relationship: 1.45≤Nd8≤1.65, 55.00≤Vd8≤82.00. Such a setting is conducive to correcting the chromatic aberration of the telephoto infrared synchronous imaging lens and ensuring the resolution performance. At the same time, it can maintain the stability of the effective focal length of the lens in different temperature environments, realize the automatic temperature compensation function, and ensure the imaging quality in different temperature environments.

[0060] In the telephoto infrared synchronous imaging lens of the present invention, the refractive index Nd9 and the Abbe number Vd9 of the ninth lens L9 satisfy the relationship: 1.55≤Nd9≤1.65, 35.00≤Vd9≤38.50. Such a setting is conducive to correcting the chromatic aberration of the telephoto infrared synchronous imaging lens and ensuring the resolution performance. It can achieve the confocal of visible light and infrared light, ensuring that the resolution requirements of visible light and infrared light can be taken into account at the same time.

[0061] In the telephoto infrared synchronous imaging lens of the present invention, the refractive index Nd10 and the Abbe number Vd10 of the tenth lens L10 satisfy the relationship: 1.85≤Nd10≤2.05, 28.00≤Vd10≤36.50. Such a setting is conducive to correcting the chromatic aberration of the telephoto infrared synchronous imaging lens and ensuring the resolution performance. It can achieve the confocal of visible light and infrared light, ensuring that the resolution requirements of visible light and infrared light can be taken into account at the same time.

[0062] The telephoto infrared synchronous imaging lens of the present invention satisfies the relationship between the half image height IH of the telephoto infrared synchronous imaging lens and the effective focal length EFL of the telephoto infrared synchronous imaging lens: 0.13≤IH / EFL≤0.20. Satisfying the above relationship can ensure that the lens system meets the advantageous performance of a large target surface, can be used with various types of chips, and can effectively control the distortion of the optical system to achieve a low-distortion imaging effect.

[0063] The telephoto infrared synchronous imaging lens of the present invention satisfies the relationship: 1.70≤TTL / EFL≤2.00;

[0064] Wherein, TTL represents the on-axis distance from the object side of the first lens L1 to the target surface, and EFL represents the effective focal length of the telephoto infrared synchronous imaging lens. With such an arrangement, under the premise of ensuring the total length of the optical system, there is sufficient space from the image plane of the twelfth lens L12 to the target surface to meet the flange distance requirement; there is sufficient space to place the filter element to effectively filter out the influence of the non-imaging spectrum, ensuring that high-resolution visible light and infrared light imaging quality can be obtained respectively.

[0065] In summary, the telephoto infrared synchronous imaging lens of the present invention can achieve confocality of visible light and infrared light, and does not require additional fill light equipment for night operation. It also has the superior performance of large aperture (FNO≤1.6) and large target surface (half image height IH≥7.8mm), can obtain high-definition imaging pictures for both visible and infrared spectra, and has a temperature compensation function.

[0066] According to the above configuration of the present invention, four groups of specific implementations are given below to specifically illustrate the lens according to the present invention.

[0067] The data of the four implementation methods are shown in Table 1 below:

[0068] Conditional expression Example 1 Example 2 Example 3 Example 4 0.13≤IH / EFL≤0.20 0.189 0.173 0.157 0.149 1.60≤Nd4≤1.75 1.71 1.68 1.66 1.64 29.00≤Vd4≤34.00 29.51 31.16 33.05 33.84 1.75≤Nd5≤1.85 1.84 1.80 1.80 1.78 22.00≤Vd5≤26.00 23.78 22.70 25.46 25.72 1.45≤Nd6≤1.65 1.61 1.61 1.60 1.49 55.00≤Vd6≤82.00 55.77 63.39 65.47 81.61 1.60≤Nd7≤1.80 1.67 1.68 1.69 1.71 29.0≤Vd7≤32.50 32.17 31.16 30.05 29.50 1.45≤Nd8≤1.65 1.61 1.61 1.60 1.49 55.00≤Vd8≤82.00 55.77 63.39 65.47 81.61 1.55≤Nd9≤1.65 1.60 1.61 1.62 1.62 35.00≤Vd9≤38.50 38.01 37.00 36.35 35.70 1.85≤Nd10≤2.05 1.95 2.00 1.91 1.90 28.00≤Vd10≤36.50 32.31 28.32 35.25 31.42 1.70≤TTL / EFL≤2.00 1.98 1.91 1.82 1.83

[0069] Table 1

[0070] Implementation method 1:

[0071] Figure 1 FIG. 1 is a schematic diagram showing the structure of a telephoto infrared synchronous imaging lens according to Embodiment 1 of the present invention.

[0072] Table 2 below lists the relevant parameters of each lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0073] Surface number Surface type Radius of curvature thickness Refractive Index Abbe number S1 Spherical 39.63 3.01 1.80 41.02 S2 Spherical 70.68 0.10 S3 Spherical 23.83 4.80 1.83 37.22 S4 Spherical 40.13 0.80 1.68 31.16 S5 Spherical 17.82 8.01 S6 Spherical -47.02 0.90 1.71 29.50 S7 Spherical 20.73 7.57 1.84 23.78 S8 Spherical -57.44 1.94 S9(STOP) Spherical Infinity 2.32 S10 Spherical 90.47 9.14 1.61 55.77 S11 Spherical -17.33 1.20 1.67 32.17 S12 Spherical 15.70 7.89 1.61 55.77 S13 Spherical -45.81 3.91 S14 Spherical -20.92 2.50 1.60 38.01 S15 Spherical 35.44 6.50 1.95 32.31 S16 Spherical -35.44 8.25 S17 Spherical -20.18 0.80 1.59 39.22 S18 Spherical 30.04 3.56 1.88 40.13 S19 Spherical -145.55 0.56 S20 Spherical Infinity 1.60 1.51 64.21 S21 Spherical Infinity 18.93 S22 (image plane) Spherical Infinity

[0074] Table 2

[0075] In this embodiment, the effective focal length EFL of the lens is 47.62 mm, the aperture FNO is 1.59, and the half image height IH is 9.00. The second lens L2 and the third lens L3, the fourth lens L4 and the fifth lens L5, the ninth lens L9 and the tenth lens L10, the eleventh lens L11 and the second lens L12 respectively form a doublet, and the sixth lens L6, the seventh lens L7 and the eighth lens L8 form a triplet.

[0076] Figure 2-5The visible light MTF diagram, infrared light Through-Focus-MTF diagram, Through-Focus-MTF diagram at -40°C and Through-Focus-MTF diagram at 85°C of the telephoto infrared synchronous imaging lens of Example 1 are schematically shown respectively. It can be seen from the accompanying drawings that the telephoto infrared synchronous imaging lens obtained according to Example 1 of the present invention can achieve confocality of visible light and infrared light, and has the superior performance of large aperture (FNO≤1.6) and large target surface (half image height IH≥7.8mm), and has a temperature compensation function, and is not out of focus in the temperature range of -40°C to +85°C.

[0077] Implementation method 2:

[0078] Figure 6 FIG. 1 is a schematic diagram showing the structure of a telephoto infrared synchronous imaging lens according to Embodiment 2 of the present invention.

[0079] Table 3 below lists the relevant parameters of each lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0080] Surface number Surface type Radius of curvature thickness Refractive Index Abbe number S1 Spherical 40.68 2.88 1.85 23.80 S2 Spherical 96.16 0.10 S3 Spherical 31.64 5.55 1.75 51.20 S4 Spherical 1288.01 1.52 S5 Spherical -400.58 0.80 1.67 34.20 S6 Spherical 20.00 5.85 S7 Spherical -42.81 0.8 1.68 31.16 S8 Spherical 49.47 3.08 1.8 22.70 S9 Spherical -160.97 5.14 S10(STOP) Spherical Infinity 2.24 S11 Spherical 60.45 8.37 1.61 63.39 S12 Spherical -30.46 0.80 1.68 31.16 S13 Spherical 16.08 7.17 1.61 63.39 S14 Spherical -100.43 0.10 S15 Spherical 30.25 7.08 1.61 37 S16 Spherical -90.48 0.80 2 28.32 S17 Spherical 19.80 8.05 S18 Spherical 50.39 5.38 1.61 36.3 S19 Spherical 17.37 7.52 1.89 39.60 S20 Spherical 89.90 3.26 S21 Spherical Infinity 1.60 1.52 64.20 S22 Spherical Infinity 15.86 S23 (image plane) Spherical Infinity

[0081] Table 3

[0082] In this embodiment, the effective focal length EFL of the lens is 49.13 mm, the aperture FNO is 1.60, and the half image height IH is 8.50. The second lens L2 and the third lens L3 are independent lenses, the fourth lens L4 and the fifth lens L5, the ninth lens L9 and the tenth lens L10, the eleventh lens L11 and the second lens L12 respectively form a doublet, and the sixth lens L6, the seventh lens L7 and the eighth lens L8 form a triplet.

[0083] Figure 7-10 The visible light MTF diagram, infrared light Through-Focus-MTF diagram, Through-Focus-MTF diagram at -40°C and Through-Focus-MTF diagram at 85°C of the telephoto infrared synchronous imaging lens of Example 2 are schematically shown respectively. It can be seen from the accompanying drawings that the telephoto infrared synchronous imaging lens obtained according to Example 2 of the present invention can achieve confocality of visible light and infrared light, and has the superior performance of large aperture (FNO≤1.6) and large target surface (half image height IH≥7.8mm), and has a temperature compensation function, and is not out of focus in the temperature range of -40°C to +85°C.

[0084] Implementation method three:

[0085] Fig.11Schematically shows the structure of a telephoto infrared synchronous imaging lens according to the third embodiment of the present invention.

[0086] Table 4 below lists the relevant parameters of each lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0087] Surface number Surface type Radius of curvature thickness Refractive Index Abbe number S1 Spherical 40.00 3.35 1.80 41.02 S2 Spherical 90.02 0.10 S3 Spherical 23.49 3.20 1.83 42.74 S4 Spherical 25.63 1.60 S5 Spherical 45.81 0.80 1.64 33.84 S6 Spherical 17.70 7.98 S7 Spherical -30.07 0.80 1.66 33.05 S8 Spherical 29.01 6.55 1.80 25.46 S9 Spherical -42.06 1.95 S10(STOP) Spherical Infinity 2.00 S11 Spherical 90.05 7.00 1.60 65.47 S12 Spherical -17.43 0.80 1.69 30.05 S13 Spherical 16.55 8.36 1.60 65.47 S14 Spherical -44.01 4.70 S15 Spherical -28.87 0.80 1.62 36.35 S16 Spherical 35.50 7.04 1.91 35.25 S17 Spherical -32.50 9.90 S18 Spherical -20.91 2.68 1.59 39.22 S19 Spherical -150.00 1.87 1.88 40.13 S20 Spherical -42.23 0.43 S21 Spherical Infinity 1.60 1.52 64.20 S22 Spherical Infinity 18.96 S23 (image plane) Spherical Infinity

[0088] Table 4

[0089] In this embodiment, the effective focal length EFL of the lens is 50.83 mm, the aperture FNO is 1.60, and the half image height IH is 7.98. The second lens L2 and the third lens L3 are independent lenses, the fourth lens L4 and the fifth lens L5, the ninth lens L9 and the tenth lens L10, the eleventh lens L11 and the second lens L12 respectively form a doublet lens, and the sixth lens L6, the seventh lens L7 and the eighth lens L8 form a triplet lens.

[0090] Figure 12-15 The visible light MTF diagram, infrared light Through-Focus-MTF diagram, Through-Focus-MTF diagram at -40°C and Through-Focus-MTF diagram at 85°C of the telephoto infrared synchronous imaging lens of Example 3 are schematically shown respectively. It can be seen from the accompanying drawings that the telephoto infrared synchronous imaging lens obtained according to Example 3 of the present invention can achieve confocality of visible light and infrared light, and has the superior performance of large aperture (FNO≤1.6) and large target surface (half image height IH≥7.8mm), and has a temperature compensation function, and is not out of focus in the temperature range of -40°C to +85°C.

[0091] Implementation Method 4

[0092] Fig.16 FIG. 4 is a diagram schematically showing the structure of a telephoto infrared synchronous imaging lens according to a fourth embodiment of the present invention.

[0093] Table 5 below lists the relevant parameters of each lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number:

[0094] Surface number Surface type Radius of curvature thickness Refractive Index Abbe number S1 Spherical 39.59 3.05 1.85 23.80 S2 Spherical 50.11 0.71 S3 Spherical 27.66 5.82 1.78 50.40 S4 Spherical 210.41 1.76 S5 Spherical 700.32 0.80 1.69 34.80 S6 Spherical 15.62 6.83 S7 Spherical -36.75 1.20 1.64 33.84 S8 Spherical 60.35 3.12 1.78 25.72 S9 Spherical -70.43 1.95 S10(STOP) Spherical Infinity 2.00 S11 Spherical 88.33 8.62 1.49 81.61 S12 Spherical -16.04 0.80 1.71 29.50 S13 Spherical 17.45 8.73 1.49 81.60 S14 Spherical -63.66 0.81 S15 Spherical 56.65 7.62 1.62 35.7 S16 Spherical -24.02 0.82 1.90 31.42 S17 Spherical 21.73 6.33 S18 Spherical 29.48 9.00 1.88 41.00 S19 Spherical -160.00 4.67 1.49 70.40 S20 Spherical 46.810 3.40 S21 Spherical Infinity 1.60 1.51 64.21 S22 Spherical Infinity 16.00 S23 (image plane) Spherical Infinity

[0095] Table 5

[0096] In this embodiment, the effective focal length EFL of the lens is 52.35 mm, the aperture FNO is 1.60, and the half image height IH is 7.80. The second lens L2 and the third lens L3 are independent lenses, the fourth lens L4 and the fifth lens L5, the ninth lens L9 and the tenth lens L10, the eleventh lens L11 and the second lens L12 respectively form a doublet lens, and the sixth lens L6, the seventh lens L7 and the eighth lens L8 form a triplet lens.

[0097] Figure 17-20 The visible light MTF diagram, infrared light Through-Focus-MTF diagram, Through-Focus-MTF diagram at -40°C and Through-Focus-MTF diagram at 85°C of the telephoto infrared synchronous imaging lens of Example 4 are schematically shown respectively. It can be seen from the accompanying drawings that the telephoto infrared synchronous imaging lens obtained according to Example 4 of the present invention can achieve confocality of visible light and infrared light, and has the superior performance of large aperture (FNO≤1.6) and large target surface (half image height IH≥7.8mm), and has a temperature compensation function, and is not out of focus in the temperature range of -40°C to +85°C.

[0098] The above is only one embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A telephoto infrared synchronous imaging lens, characterized in that: The optical system includes, from the object side to the image side, a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a stop, a sixth lens (L6), a seventh lens (L7), an eighth lens (L8), a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11) and a twelfth lens (L12); The first lens (L1), the second lens (L2), the fifth lens (L5), the sixth lens (L6) and the eighth lens (L8) are positive power lenses; The third lens (L3), the fourth lens (L4) and the seventh lens (L7) are negative power lenses.

2. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: Along the direction from the object side to the image side, the first lens (L1) and the second lens (L2) are convex-concave lenses; the third lens (L3) is a convex-concave lens, a concave-concave lens or a plano-concave lens.

3. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The fourth lens (L4) and the seventh lens (L7) are concave-concave lenses, and the fifth lens (L5), the sixth lens (L6) and the eighth lens (L8) are convex-convex lenses.

4. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The second lens (L2) and the third lens (L3) are arranged as a single lens or form a doublet lens.

5. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The fourth lens (L4) and the fifth lens (L5) form a doublet lens.

6. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The sixth lens (L6), the seventh lens (L7) and the eighth lens (L8) form a triplet lens.

7. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The ninth lens (L9) and the tenth lens (L10) form a doublet lens.

8. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The eleventh lens (L11) and the twelfth lens (L12) form a doublet lens.

9. The telephoto infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd4 and the Abbe number Vd4 of the fourth lens (L4) satisfy the relationship: 1.60≤Nd4≤1.75, 29.00≤Vd4≤34.

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10. The long-focus infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd5 and the Abbe number Vd5 of the fifth lens (L5) satisfy the relationship: 1.75≤Nd5≤1.85, 22.00≤Vd4≤26.

00.

11. The long-focus infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd6 and the Abbe number Vd6 of the sixth lens (L6) satisfy the relationship: 1.45≤Nd6≤1.65, 55.00≤Vd6≤82.

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12. The long-focus infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd7 and the Abbe number Vd7 of the seventh lens (L7) satisfy the relationship: 1.60≤Nd7≤1.80, 29.00≤Vd7≤32.

50.

13. The telephoto infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd8 and the Abbe number Vd8 of the eighth lens (L8) satisfy the relationship: 1.45≤Nd8≤1.65, 55.00≤Vd8≤82.

00.

14. The telephoto infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd9 and the Abbe number Vd9 of the ninth lens (L9) satisfy the relationship: 1.55≤Nd9≤1.65, 35.00≤Vd9≤38.

50.

15. The telephoto infrared synchronous imaging lens according to any one of claims 1 to 8, characterized in that: The refractive index Nd10 and the Abbe number Vd10 of the tenth lens (L10) satisfy the relationship: 1.85≤Nd10≤2.05, 28.00≤Vd10≤36.

50.

16. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: The half image height IH of the telephoto infrared synchronous imaging lens and the effective focal length EFL of the telephoto infrared synchronous imaging lens satisfy the relationship: 0.13≤IH / EFL≤0.

20.

17. The telephoto infrared synchronous imaging lens according to claim 1, characterized in that: As mentioned above, the relationship is satisfied: 1.70≤TTL / EFL≤2.00; The TTL represents the on-axis distance from the object side surface of the first lens (L1) to the target surface, and the EFL represents the effective focal length of the telephoto infrared synchronous imaging lens.

Images