A vehicle-mounted infrared camera

Abstract

This invention provides a vehicle-mounted infrared lens, comprising: a first lens, a second lens, and a third lens arranged sequentially from the object side to the image side along the optical axis, all having positive optical power; the second lens is a superlens; the front surface of the first lens is convex, and the rear surface is concave; the rear surface of the third lens is convex. The vehicle-mounted infrared lens provided by this invention, because the second lens is a superlens with good pyrolysis effect, makes the vehicle-mounted infrared lens insensitive to temperature and enables clear imaging; since the vehicle-mounted infrared lens does not include other cooling devices, it has a smaller overall system length, a simpler structure, and better aligns with the trend of miniaturization in vehicle-mounted lenses, thus reducing costs.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and more specifically, to a vehicle-mounted infrared lens. Background Technology

[0002] With the development of artificial intelligence, autonomous driving is gaining increasing popularity, which in turn places higher demands on in-vehicle imaging systems that capture environmental information. In-vehicle infrared cameras utilize the principle of thermal imaging, capturing the heat radiated by objects to form images. In specific environments such as nighttime, areas with alternating light and dark, and foggy weather, in-vehicle infrared cameras can observe surrounding objects in a timely and accurate manner. However, because of the thermal imaging principle of in-vehicle infrared cameras, the lenses are susceptible to temperature effects, which ultimately affects the image quality.

[0003] Current automotive infrared lenses consist of three traditional lenses and two spacers. One spacer is positioned between the first and second lenses, while the other is positioned between the second and third lenses. Heat dissipation holes on the spacers help maintain the optical system's temperature within a reasonable range, achieving clear imaging. However, this type of automotive infrared lens has a relatively large overall system length and a complex structure, which does not align with the trend towards miniaturization in automotive lenses and also increases costs. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a vehicle-mounted infrared lens.

[0005] In a first aspect, embodiments of the present invention provide a vehicle-mounted infrared lens comprising a first lens, a second lens, and a third lens arranged sequentially along a common optical axis from the object side to the image side; the first lens, the second lens, and the third lens all have positive optical power; the second lens is a superlens, and the first lens and the third lens are refractive lenses; the front surface of the first lens is convex, and the rear surface is concave; the rear surface of the third lens is convex; the front surface represents the side of the lens closer to the object side, and the rear surface represents the side of the lens farther from the object side.

[0006] Optionally, the material of the refractive lens satisfies the following condition:

[0007] in, The temperature coefficient of refractive index represents the material of the refracting lens.

[0008] Optionally, the vehicle-mounted infrared camera meets the following condition:

[0009]

[0010] Wherein, Fov represents the half field of view of the vehicle-mounted infrared camera; TTL represents the total system length of the vehicle-mounted infrared camera.

[0011] Optionally, the vehicle-mounted infrared camera meets the following condition:

[0012]

[0013] Where f represents the focal length of the vehicle-mounted infrared lens; D e This indicates the entrance pupil diameter of the vehicle-mounted infrared lens.

[0014] Optionally, the optical power of the first lens and the third lens satisfies the following condition:

[0015]

[0016] in, This indicates the optical power of the first lens. This indicates the optical power of the third lens.

[0017] Optionally, the optical power of the second lens satisfies the following condition:

[0018]

[0019] in, This indicates the optical power of the second lens; This indicates the optical power of the vehicle-mounted infrared lens.

[0020] Optionally, the curvature of the front surface and the curvature of the rear surface of the refractive lens satisfy the following condition:

[0021]

[0022] Wherein, c1 represents the curvature of the front surface of the refractive lens; and c2 represents the curvature of the rear surface of the refractive lens.

[0023] Optionally, the refractive lens satisfies the following condition:

[0024]

[0025] Wherein, R represents the radius of curvature of the refractive lens; d represents the thickness of the refractive lens; CT represents the center thickness of the refractive lens; and ET represents the edge thickness of the refractive lens.

[0026] Optionally, the Abbe number of the refracting lens satisfies the following condition:

[0027]

[0028] Among them, v d The Abbe number of the refracting lens; v m This represents the Abbe number of the second lens.

[0029] Optionally, the second lens includes a substrate and nanostructures periodically arranged on at least one side of the substrate; wherein the refractive index temperature coefficient of the nanostructures is less than the reference refractive index temperature coefficient; or, the nanostructures are composed of at least two materials, and the product of the refractive index temperature coefficients of the at least two materials is less than zero; the reference refractive index temperature coefficient is greater than or equal to 0.01 × 10⁻⁶. -6 / K, and less than or equal to 3000×10 -6 / K.

[0030] In the solution provided by the first aspect of the present invention, since the second lens is a superlens with good pyrolysis effect, the vehicle infrared lens is not sensitive to temperature and can achieve clear imaging. In addition, since the superlens has the advantages of light weight, thin thickness and low price, and the vehicle infrared lens does not include any other cooling devices, the vehicle infrared lens has a small overall system length, simple structure, which is more in line with the development trend of miniaturization of vehicle lenses, and also reduces costs.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This diagram illustrates the structure of a vehicle-mounted infrared lens provided in an embodiment of the present invention.

[0034] Figure 2 A schematic diagram of the modulation transfer function of Embodiment 1 provided in this invention is shown;

[0035] Figure 3 A schematic diagram of the vertical color difference of Embodiment 1 provided in this invention is shown;

[0036] Figure 4 A schematic diagram of field curvature and distortion of Embodiment 1 provided by the present invention is shown;

[0037] Figure 5 This diagram illustrates the modulation transfer function of Embodiment 1 provided by the present invention at -40 degrees Celsius.

[0038] Figure 6This diagram illustrates the modulation transfer function of Embodiment 1 provided by the present invention at 80 degrees Celsius.

[0039] Figure 7 A schematic diagram of the structure of Embodiment 2 provided by the present invention is shown;

[0040] Figure 8 A schematic diagram of the modulation transfer function of Embodiment 2 provided in this invention is shown;

[0041] Figure 9 A schematic diagram of the vertical color difference of Embodiment 2 provided in this invention is shown;

[0042] Figure 10 A schematic diagram of field curvature and distortion of Embodiment 2 provided by the present invention is shown;

[0043] Figure 11 This diagram illustrates the modulation transfer function of Embodiment 2 provided by the present invention at -40 degrees Celsius.

[0044] Figure 12 This diagram illustrates the modulation transfer function of Embodiment 2 provided by the present invention at 80 degrees Celsius.

[0045] Figure 13 A schematic diagram of the structure of Embodiment 3 provided in this invention is shown;

[0046] Figure 14 A schematic diagram of the modulation transfer function of Embodiment 3 provided in this embodiment of the invention is shown;

[0047] Figure 15 A schematic diagram of the vertical color difference of Embodiment 3 provided in this invention is shown;

[0048] Figure 16 A schematic diagram of field curvature and distortion of Embodiment 3 provided in this invention is shown;

[0049] Figure 17 This diagram illustrates the modulation transfer function of Embodiment 3 provided by the present invention at -40 degrees Celsius.

[0050] Figure 18 The diagram shows the modulation transfer function of Embodiment 3 provided by the present invention at 80 degrees Celsius.

[0051] icon:

[0052] 1-First lens, 2-Second lens, 3-Third lens, 4-Filter, 5-Image plane. Detailed Implementation

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] This invention provides a vehicle-mounted infrared camera, see [link / reference]. Figure 1 As shown, the vehicle-mounted infrared camera includes: a first lens 1, a second lens 2, and a third lens 3 arranged sequentially along the optical axis from the object side to the image side; all three lenses have positive optical power; the second lens 2 is a superlens, and the first lens 1 and the third lens 3 are refractive lenses. Figure 1 The left side represents the object side, and the right side represents the image side. Figure 1 The rightmost side also shows filter 4 and image plane 5.

[0057] like Figure 1 As shown, the front surface of the first lens 1 is convex, and the rear surface is concave; the rear surface of the third lens 3 is convex. The front surface refers to the side of the lens closest to the object, such as... Figure 1 As shown, the front surface of the first lens 1 is the left side surface of the first lens 1; the rear surface represents the side of the lens away from the object, as shown. Figure 1As shown, the rear surface of the first lens 1 is the right side surface of the first lens 1, and the rear surface of the third lens 3 is the right side surface of the third lens 3. It should be noted that the front surface of the third lens 3 (i.e.,...) Figure 1 The left surface of the third lens 3 can be either convex or concave, and this embodiment of the invention does not limit this. Therefore, based on the surface shape of the two sides of the first lens 1, it can be known that the first lens 1 can be a meniscus convex towards the object.

[0058] The vehicle-mounted infrared lens may also include an aperture stop, which can be positioned at any location before the front surface of the second lens 2. Specifically, the aperture stop can be positioned on the front surface of the second lens 2, or on any surface of the first lens 1, or between the first lens 1 and the second lens 2, or before the front surface of the first lens 1. For example, the aperture stop can be positioned on the surface of the second lens 2 closer to the object to control the amount of light entering.

[0059] The vehicle-mounted infrared lens provided in this embodiment of the invention has a second lens 2 that is a superlens with good pyrolysis effect, which makes the vehicle-mounted infrared lens insensitive to temperature and can achieve clear imaging. In addition, since the superlens has the advantages of being lightweight, thin, and inexpensive, and since the vehicle-mounted infrared lens does not include any other cooling devices, the vehicle-mounted infrared lens has a small overall system length and a simple structure, which is more in line with the development trend of miniaturization of vehicle-mounted lenses and also reduces costs.

[0060] Optionally, in order to further eliminate the thermal difference effect of the system, the materials of the refractive lenses (i.e., the first lens 1 and the third lens 3) in this embodiment of the invention must satisfy the following condition:

[0061]

[0062] in, The temperature coefficient of refractive index represents the material of the refractive lens, Δn represents the change in refractive index, and Δt represents the change in temperature. Based on the conditional formula of this temperature coefficient of refractive index, it can be seen that the lower the temperature coefficient of refractive index of the material of the refractive lens (i.e., the first lens 1 and the third lens 3), the smaller the range of change of the refractive index of the material with temperature. In other words, the material is not sensitive to temperature. The performance output of the refractive lens made of this material is more stable under different temperature environments, thus making the vehicle infrared lens less sensitive to temperature and enabling clearer imaging.

[0063] Optionally, the vehicle-mounted infrared camera meets the following condition:

[0064]

[0065] Where Fov represents the half field of view of the vehicle-mounted infrared lens; TTL represents the total system length of the vehicle-mounted infrared lens; in conditional equation (2), the lower limit (e.g., 0.94) helps control the total system length, making the system more compact; the upper limit (e.g., 1.09) helps control the light deflection amplitude, that is, to make the light deflect reasonably as much as possible, avoiding the introduction of unnecessary aberrations, thereby increasing the number of lenses or using more aspherical lenses to correct the introduced aberrations. For example, The value can be 0.98, 1.00, 1.05 or 1.03, etc.

[0066] Specifically, when the ratio of Fov to TTL is larger, although the system is more compact (the smaller the TTL), it also leads to a greater degree of light deflection, making it difficult for the light to converge smoothly on the image plane, resulting in more aberrations. When the ratio of Fov to TTL is smaller, the system is more loose (the larger the TTL), resulting in a larger size. Therefore, when the embodiment of the present invention satisfies the above conditional expression (2), the total length of the system can be reduced as much as possible, making the overall size of the vehicle-mounted infrared lens more compact. In addition, the light can be reasonably deflected, for example, the light can converge smoothly on the image plane, avoiding the introduction of more aberrations.

[0067] Optionally, the vehicle-mounted infrared camera meets the following condition:

[0068]

[0069] Where f represents the focal length (e.g., effective focal length) of the vehicle-mounted infrared camera; D e This indicates the entrance pupil diameter of the vehicle-mounted infrared lens. In this embodiment of the invention, condition (3) can be used to represent the aperture of the vehicle-mounted infrared lens, i.e., the aperture of the optical system; the smaller the ratio of the focal length to the entrance pupil diameter of the vehicle-mounted infrared lens, the larger the aperture of the vehicle-mounted infrared lens; in other words, when the aperture of the vehicle-mounted infrared lens satisfies the above condition (3), the vehicle-mounted infrared lens can have a large aperture. For example, The value can be 1.00, 0.80, etc.

[0070] Optionally, the optical power of the first lens 1 and the third lens 3 satisfies the following condition:

[0071]

[0072] in, This indicates the optical power of the first lens 1. This indicates the optical power of the third lens 3.

[0073] In this embodiment of the invention, the control condition (4) helps to reduce entrance pupil aberration, smooth light deflection, and improve the imaging quality of the system. Specifically, the smaller the ratio of the above condition (4), the better. The larger the value of the first lens 1, the more optical power it can allocate. However, excessive optical power of the first lens 1 can introduce a large amount of entrance pupil aberration, reducing the system's imaging quality and slowing down ray tracing. Therefore, setting a lower limit (e.g., 1.8) in the above conditional equation (4) is to prevent the introduction of excessive entrance pupil aberration. The larger the ratio of the above conditional equation (4), the more optical power is allocated to the first lens 1. The larger the focal length, the more optical power the third lens 3 allocates. However, when the third lens 3 occupies too much optical power, the light rays are significantly deflected on its surface, which will also introduce excessive aberrations, resulting in poor system imaging quality. Furthermore, the system is sensitive to tolerances. Therefore, setting an upper limit (e.g., 4.1) in the above conditional equation (4) is to prevent excessive light deflection from introducing aberrations and simultaneously reduce the system's tolerance sensitivity. For example, The value can be 1.90, 2.00, 2.50, 2.80, 3.00, 3.40, 3.80 or 4.00, etc.

[0074] Optionally, the optical power of the second lens 2 satisfies the following condition:

[0075]

[0076] in, This indicates the optical power of the second lens 2, i.e., the optical power of the superlens; This indicates the optical power of the vehicle-mounted infrared camera, i.e., the overall optical power. The optical power provided by the second lens 2 (superlens) The larger the value, the more pronounced the chromatic dispersion on the surface of the second lens 2, resulting in greater axial chromatic aberration. Therefore, excessive axial chromatic aberration can be avoided by setting an upper limit (e.g., 0.75) in conditional expression (5). That is, setting an upper limit in conditional expression (5) helps control the axial chromatic aberration of the system, while setting a lower limit (e.g., 0.20) ensures that the second lens 2 (superlens) can provide sufficient optical power. Based on this, when the vehicle-mounted infrared lens satisfies conditional expression (5), the second lens 2 can provide reasonable optical power to the system and avoid excessive axial chromatic aberration. For example, The value can be 0.22, 0.25, 0.40, 0.50, 0.60, 0.70 or 0.72, etc.

[0077] Optionally, the curvature of the front surface and the curvature of the rear surface of the refractive lens satisfy the following condition:

[0078]

[0079] Where c1 represents the curvature of the front surface of the refractive lens; and c2 represents the curvature of the rear surface of the refractive lens.

[0080] Optionally, the refractive lens satisfies the following condition:

[0081]

[0082]

[0083] Where R represents the radius of curvature of the refractive lens; d represents the thickness of the refractive lens; CT represents the center thickness of the refractive lens; and ET represents the edge thickness of the refractive lens.

[0084] In this embodiment of the invention, the refractive lens includes a first lens 1 and a third lens 3. The curvature of the front surface and the curvature of the rear surface of the first lens 1 can satisfy the above-mentioned condition (6), and the curvature of the front surface and the curvature of the rear surface of the third lens 3 can also satisfy the above-mentioned condition (6); the radius of curvature of the first lens 1 can satisfy the above-mentioned condition (7), and the radius of curvature of the third lens 3 can also satisfy the above-mentioned condition (7); the center thickness and the edge thickness of the first lens 1 can satisfy the above-mentioned condition (8), and the center thickness and the edge thickness of the third lens 3 can also satisfy the above-mentioned condition (8).

[0085] Specifically, in this embodiment of the invention, the curvature of the refractive lens can be controlled by controlling the curvature of the front and rear surfaces of the refractive lens to satisfy the above-mentioned condition (6). By controlling the radius of curvature of the refractive lens to satisfy the above-mentioned condition (7), and by controlling the center thickness and edge thickness of the refractive lens to satisfy the above-mentioned condition (8), it can be ensured that the first lens 1 and the third lens 3 in the vehicle-mounted infrared lens can be processed by conventional methods, reducing the processing difficulty, and also ensuring that the light is gently deflected in the vehicle-mounted infrared lens, increasing the tolerance.

[0086] For example, The value can be 0.95, 1.70, 2.50, 3.50, 5.00, 7.00, 8.00, 10.00, or 12.00, etc.; The value can be 1.60, 1.80, or 2.00, etc.; The value can be 1.28, 1.40, 1.55 or 1.66, etc.

[0087] Optionally, the Abbe number of the refracting lens satisfies the following condition:

[0088]

[0089] The Abbe number is an index used to represent the dispersion capability of a transparent medium; v d The Abbe number of a refracting lens, i.e., v d Indicates the dispersive ability of a refracting lens; v m This represents the Abbe number of the second lens 2, i.e., v m This indicates the dispersive power of the second lens 2 (superlens). Specifically, And λ1 < λ2 < λ3; where λ1, λ2, and λ3 can be any infrared wavelength, for example, λ1 can be equal to 8μm, λ2 can be equal to 10μm, and λ3 can be equal to 12μm. Therefore, the dispersion introduced by the second lens 2 (superlens) is negative dispersion. Thus, to eliminate the chromatic aberration of the system, the refractive lens needs to provide a certain amount of positive dispersion for chromatic aberration correction. The smaller the value of the above conditional equation (9), the smaller the Abbe number of the refractive lens; where the lower limit of the above conditional equation (9) is to prevent the refractive lens from introducing excessive dispersion, and the upper limit is to ensure that the refractive lens can provide sufficient positive dispersion to correct the negative dispersion introduced by the second lens 2, thereby effectively controlling the system dispersion. For example, The value can be 40.00, 50.50, 65.00, 70.00 or 81.00, etc.

[0090] Optionally, the second lens 2 includes a substrate and nanostructures periodically arranged on at least one side of the substrate; wherein the refractive index temperature coefficient of the nanostructures is less than the reference refractive index temperature coefficient; or, the nanostructures are composed of at least two materials, and the product of the refractive index temperature coefficients of the at least two materials is less than zero; the reference refractive index temperature coefficient is greater than or equal to 0.01 × 10⁻⁶. -6 / K, and less than or equal to 3000×10 -6 / K, preferably, the reference refractive index temperature coefficient is less than or equal to 1500 × 10⁻⁶. -6 / K.

[0091] The refractive index temperature coefficient refers to the change in refractive index per unit temperature, and the reference refractive index temperature coefficient is determined by the operating temperature range of the second lens 2. The nanostructure can be composed of a single material, preferably a material with a refractive index temperature coefficient smaller than the reference refractive index temperature coefficient. Alternatively, it can be composed of two or more materials. In such nanostructures, the product of the refractive index temperature coefficients of all materials is less than zero. This embodiment of the invention adjusts the equivalent refractive index temperature coefficient of the nanostructure to make the equivalent refractive index of the nanostructure insensitive to temperature, thereby making the second lens 2 insensitive to temperature.

[0092] Among them, the first lens 1 is a spherical lens or an even-order aspherical lens; the third lens 3 is an even-order aspherical lens.

[0093] Refractive lenses can be divided into spherical lenses and aspherical lenses; aspherical lenses can be further divided into odd-order aspherical lenses and even-order aspherical lenses. In this embodiment of the invention, the first lens 1, which is closer to the object side, can be a spherical lens or an even-order aspherical lens; the third lens 3, which is closer to the image side, can be an even-order aspherical lens.

[0094] Among them, the surface sag of even-order aspherical lenses satisfies:

[0095]

[0096] Where z represents the surface sag of the even-order aspherical lens (such as the third lens 3), specifically, the surface sag is a surface vector parallel to the z-axis, which is the principal optical axis of the vehicle-mounted infrared lens provided in this embodiment of the invention; c represents the curvature of the vertex of the even-order aspherical lens; k represents the conic coefficient of the even-order aspherical lens, and in order to meet the process requirements, the value range of k is (-100, 100); r1 represents the distance from a point on the surface of the even-order aspherical lens to the center; A, B, C, D, E, F, G, H and I are the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th and 20th order coefficients of the even-order aspherical lens, respectively.

[0097] The second lens 2 includes a nanostructure disposed on one side surface (such as the front surface of the second lens 2). By arranging the nanostructure according to a certain phase distribution, the second lens 2 can provide phase compensation for the system, thereby correcting system aberrations. The phase distribution of the second lens 2 satisfies one of the following formulas:

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] Where r2 represents the distance from the center of the second lens 2 to any nanostructure on its surface, and λ represents the operating wavelength of the second lens 2; The phase is related to the operating wavelength; (x,y) represents the coordinates of the nanostructure on the second lens 2; f m Indicates the focal length of the second lens 2; a i b i a ij and b ij Each represents the phase coefficient of its respective order.

[0107] In this embodiment of the invention, the phase distribution of the second lens 2 (i.e., the superlens) can be expressed by a high-order polynomial, which includes odd-order polynomials and even-order polynomials. In order not to destroy the rotational symmetry of the phase distribution of the second lens 2, it is usually only possible to optimize the phase corresponding to the even-order polynomial, which greatly reduces the design freedom of the superlens. However, among the above formulas (10) to (17), formulas (13), (14) and (15) can also optimize the phase that satisfies the odd-order polynomial without destroying the rotational symmetry of the phase distribution of the second lens 2, thereby greatly improving the optimization freedom of the second lens 2.

[0108] The present application will now be described by way of example with reference to Embodiments 1 to 3.

[0109] Example 1:

[0110] This embodiment 1 provides a vehicle-mounted infrared camera, see [link]. Figure 1 As shown, in this embodiment 1, a first lens 1, a second lens 2, and a third lens 3 are sequentially arranged from the object side to the image side. The first lens 1 and the third lens 3 are both even-order aspherical lenses, and the second lens 2 is a superlens. The system parameters, surface parameters, and aspherical coefficients of each order of the vehicle-mounted infrared lens are shown in Tables 1-1, 1-2, and 1-3, respectively.

[0111] parameter data Total System Length (TTL) 22.0mm Field of view (2ω) 41.4° F-number 1.03 Effective focal length 13.3mm Operating band Far-infrared (8μm-12μm)

[0112] Table 1-1

[0113]

[0114]

[0115] Table 1-2

[0116]

[0117] Table 1-3

[0118] It should be noted that in Table 1-2, surface number 1 is the front surface of the first lens 1, surface number 2 is the rear surface of the first lens 1, surface number 3 is the front surface of the second lens 2, surface number 4 is the rear surface of the second lens 2, surface number 5 is the front surface of the third lens 3, and surface number 6 is the rear surface of the third lens 3. In addition, surface number 7 and surface number 8 are used to represent the front and rear surfaces of the filter 4, respectively, and surface number 9 is the image plane. The following embodiments are consistent and will not be described again.

[0119] Furthermore, the performance output of Example 1 is as follows: Figures 2 to 6 As shown, Figure 2A schematic diagram of the modulation transfer function (MTF) of the vehicle-mounted infrared camera provided in Embodiment 1 is shown. Figure 3 This diagram illustrates the vertical chromatic aberration of the vehicle-mounted infrared lens provided in Embodiment 1. Figure 4 A schematic diagram of the field curvature and distortion of the vehicle-mounted infrared lens provided in Embodiment 1 is shown. Figure 5 This diagram illustrates the modulation transfer function of the vehicle-mounted infrared lens provided in Embodiment 1 at -40 degrees Celsius. Figure 6 A schematic diagram of the modulation transfer function of the vehicle-mounted infrared lens provided in Embodiment 1 at 80 degrees Celsius is shown. Figure 2 It can be seen that the modulation transfer function of the vehicle-mounted infrared lens in Example 1 is close to the diffraction limit in different fields of view, and the curve is flat, indicating that the system has high contrast for low-frequency signals of the imaged object and high resolution for high-frequency signals of the imaged object; Figure 3 It can be seen that the system's chromatic aberration is controlled within the Airy disk, and the chromatic aberration is well constrained; Figure 4 As shown in the left part, the field curvature of this vehicle-mounted infrared camera is within the range of (-0.05mm, 0.05mm), indicating excellent field curvature control capability; Figure 4 As shown in the right part, the absolute value of the distortion of this vehicle-mounted infrared camera is less than 5%, indicating excellent distortion control capabilities; Figure 5 and Figure 6 It can be seen that the vehicle-mounted infrared lens provided in Embodiment 1 is not sensitive to temperature. In summary, the field curvature, distortion, and chromatic aberration of the vehicle-mounted infrared lens provided in Embodiment 1 are well constrained, resulting in good system imaging quality and insensitivity to temperature.

[0120] Example 2:

[0121] This embodiment 1 provides a vehicle-mounted infrared camera, see [link]. Figure 7 As shown, in this embodiment 2, a first lens 1, a second lens 2, and a third lens 3 are sequentially arranged from the object side to the image side. The first lens 1 is a spherical lens, the third lens 3 is an even-order aspherical lens, and the second lens 2 is a superlens. The system parameters of the vehicle-mounted infrared lens in embodiment 2 are consistent with those in embodiment 1, as shown in Table 1-1, and will not be repeated here. The surface parameters and aspherical coefficients of each order in this embodiment 2 are shown in Tables 2-2 and 2-3 below.

[0122]

[0123]

[0124] Table 2-2

[0125]

[0126] Table 2-3

[0127] Furthermore, the performance output of Example 2 is as follows: Figures 8 to 12 As shown, Figure 8 A schematic diagram of the modulation transfer function (MTF) of the vehicle-mounted infrared camera provided in Embodiment 2 is shown. Figure 9 This diagram illustrates the vertical chromatic aberration of the vehicle-mounted infrared lens provided in Embodiment 2. Figure 10 A schematic diagram of the field curvature and distortion of the vehicle-mounted infrared lens provided in Embodiment 2 is shown. Figure 11 This diagram illustrates the modulation transfer function of the vehicle-mounted infrared lens provided in Embodiment 2 at -40 degrees Celsius. Figure 12 A schematic diagram of the modulation transfer function of the vehicle-mounted infrared lens provided in Embodiment 2 at 80 degrees Celsius is shown. Figure 8 It can be seen that the modulation transfer function of the vehicle-mounted infrared lens in Example 2 is close to the diffraction limit in different fields of view, and the curve is flat, indicating that the system has high contrast for low-frequency signals of the imaged object and high resolution for high-frequency signals of the imaged object; Figure 9 It can be seen that the system's chromatic aberration is controlled within the Airy disk, and the chromatic aberration is well constrained; Figure 10 As shown in the left part, the field curvature of this vehicle-mounted infrared camera is within the range of (-0.05mm, 0.05mm), indicating excellent field curvature control capability; Figure 10 As shown in the right part, the absolute value of the distortion of this vehicle-mounted infrared camera is less than 5%, indicating excellent distortion control capabilities; Figure 11 and Figure 12 It can be seen that the vehicle-mounted infrared lens provided in Embodiment 2 is not sensitive to temperature. In summary, the field curvature, distortion, and chromatic aberration of the vehicle-mounted infrared lens provided in Embodiment 2 are well constrained, resulting in good system imaging quality and insensitivity to temperature.

[0128] Example 3:

[0129] This embodiment 3 provides a vehicle-mounted infrared camera, see [link]. Figure 13As shown in this embodiment 3, a first lens 1, a second lens 2, and a third lens 3 are sequentially arranged from the object side to the image side. The first lens 1 is a spherical lens, the third lens 3 is an even-order aspherical lens, and the second lens 2 is a superlens. The system parameters, surface parameters, and aspherical coefficients of this vehicle-mounted infrared lens are shown in Tables 3-1, 3-2, and 3-3, respectively.

[0130] parameter data Total System Length (TTL) 19.60mm Field of view (2ω) 41.4° F-number 1.00 Effective focal length 13.22mm Operating band Far-infrared (8μm-12μm)

[0131] Table 3-1

[0132]

[0133]

[0134] Table 3-2

[0135]

[0136] Table 3-3

[0137] Furthermore, the performance output of Example 3 is as follows: Figures 14 to 18 As shown, Figure 14 A schematic diagram of the modulation transfer function (MTF) of the vehicle-mounted infrared camera provided in Embodiment 3 is shown. Figure 15 This diagram illustrates the vertical chromatic aberration of the vehicle-mounted infrared lens provided in Embodiment 3. Figure 16 A schematic diagram of the field curvature and distortion of the vehicle-mounted infrared lens provided in this embodiment 3 is shown. Figure 17 This diagram illustrates the modulation transfer function of the vehicle-mounted infrared lens provided in Embodiment 3 at -40 degrees Celsius. Figure 18 A schematic diagram of the modulation transfer function of the vehicle-mounted infrared lens provided in Embodiment 3 at 80 degrees Celsius is shown. Figure 14 It can be seen that the modulation transfer function of the vehicle-mounted infrared lens in Example 3 is close to the diffraction limit in different fields of view, and the curve is flat, indicating that the system has high contrast for low-frequency signals of the imaged object and high resolution for high-frequency signals of the imaged object; Figure 15 It can be seen that the system's chromatic aberration is controlled within the Airy disk, and the chromatic aberration is well constrained; Figure 16 As shown in the left part, the field curvature of this vehicle-mounted infrared camera is within the range of (-0.05mm, 0.05mm), indicating excellent field curvature control capability; Figure 16 As shown in the right part, the absolute value of the distortion of this vehicle-mounted infrared camera is less than 5%, indicating excellent distortion control capabilities; Figure 17 and Figure 18It can be seen that the vehicle-mounted infrared lens provided in Embodiment 3 is not sensitive to temperature. In summary, the field curvature, distortion, and chromatic aberration of the vehicle-mounted infrared lens provided in Embodiment 3 are well constrained, the system has good imaging quality, and it is not sensitive to temperature.

[0138] Conditional summary

[0139]

[0140] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A vehicle-mounted infrared camera, characterized in that, include: A first lens (1), a second lens (2), and a third lens (3) are arranged in sequence from the object side to the image side, sharing the same optical axis. The first lens (1), the second lens (2), and the third lens (3) all have positive optical power. The second lens (2) is a superlens, and the first lens (1) and the third lens (3) are refractive lenses. The front surface of the first lens (1) is convex and the rear surface is concave; the rear surface of the third lens (3) is convex; the front surface represents the side of the lens that is closer to the object and the rear surface represents the side of the lens that is farther from the object. The curvature of the front surface and the curvature of the rear surface of the refractive lens satisfy the following condition: ； in, This represents the curvature of the front surface of the refractive lens; This indicates the curvature of the rear surface of the refractive lens.

2. The vehicle-mounted infrared lens according to claim 1, characterized in that, The material of the refractive lens satisfies the following condition: ； in, The temperature coefficient of refractive index represents the material of the refracting lens.

3. The vehicle-mounted infrared lens according to claim 1, characterized in that, The vehicle-mounted infrared camera satisfies the following condition: ； in, This indicates the half field of view of the vehicle-mounted infrared camera; This indicates the total system length of the vehicle-mounted infrared camera.

4. The vehicle-mounted infrared lens according to claim 1, characterized in that, The vehicle-mounted infrared camera satisfies the following condition: ； in, This indicates the focal length of the vehicle-mounted infrared lens; This indicates the entrance pupil diameter of the vehicle-mounted infrared lens.

5. The vehicle-mounted infrared lens according to claim 1, characterized in that, The optical power of the first lens (1) and the third lens (3) satisfies the following condition: ； in, This indicates the optical power of the first lens (1). This indicates the optical power of the third lens (3).

6. The vehicle-mounted infrared lens according to claim 1, characterized in that, The optical power of the second lens (2) satisfies the following condition: ； in, This indicates the optical power of the second lens (2); This indicates the optical power of the vehicle-mounted infrared lens.

7. The vehicle-mounted infrared lens according to claim 1, characterized in that, The refractive lens satisfies the following condition: ； ； in, This represents the radius of curvature of the refractive lens; This indicates the thickness of the refractive lens; This indicates the center thickness of the refractive lens; This indicates the edge thickness of the refractive lens.

8. The vehicle-mounted infrared camera according to claim 1, characterized in that, The Abbe number of the refracting lens satisfies the following condition: ； in, This indicates the Abbe number of the refracting lens; This represents the Abbe number of the second lens (2).

9. The vehicle-mounted infrared lens according to claim 1, characterized in that, The second lens (2) includes a substrate and nanostructures periodically arranged on at least one side of the substrate; wherein the refractive index temperature coefficient of the nanostructures is less than a reference refractive index temperature coefficient; or, the nanostructures are composed of at least two materials, the product of the refractive index temperature coefficients of the at least two materials being less than zero; the reference refractive index temperature coefficient is greater than or equal to 0.01 × 10⁻⁶. -6 / K, and less than or equal to 3000×10 -6 / K.

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