Day and night confocal catadioptric lens and image acquisition equipment

Abstract

The invention relates to a day and night confocal refraction and super lens and an image acquisition device, and belongs to the field of optical lenses, the lens has focus consistency in a visible light band and an infrared band, six lenses are sequentially arranged from an object plane to an image plane along an optical axis, at least one lens is a super-surface lens, and the rest lenses are non-super-surface lenses. According to the technical scheme, the volume and weight of the lens of the optical system are reduced, the lens can be conveniently integrated into a day and night confocal system, and miniaturization, light weight and integrated design is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of optical lenses, and in particular relates to a day and night confocal refractive index lens and image acquisition equipment. Background Art

[0002] In the security monitoring and automotive fields, cameras require lenses with day and night confocal capabilities, mainly to meet the needs of high-quality imaging in all-weather and complex environments. Visible light is the main imaging method during the day, while infrared light or low-light environments are used at night. Security monitoring needs to work around the clock, and the imaging quality must not be reduced during the day or at night. In-vehicle cameras are used for assisted driving (such as reversing images, driving recorders, ADAS, etc.), and nighttime driving safety is crucial. Ordinary lenses have different focal positions under visible and infrared light, and the focusing speed is slow in low-light conditions, which may result in blurred night images and limited application scenarios. Day and night confocal lenses, on the other hand, do not require manual adjustment and can automatically adapt to changes in lighting, providing clear images at night to help drivers identify roads and obstacles.

[0003] The day and night confocal lens includes an optical lens group, an aperture mechanism, an autofocus mechanism, a zoom mechanism, an infrared correction mechanism, a filter switching mechanism, a housing and sealing structure, a temperature compensation mechanism, an electronic control module, interface and connection components, and an auxiliary function module. These components work together to ensure that the lens can provide high-quality imaging effects both during the day and at night, and adapt to complex lighting and environmental conditions. Among them, the optical lens group is a key part of the day and night confocal lens. The resolution of traditional day and night confocal lenses in the infrared light band is usually lower than that in the visible light band, which affects the detail performance of night imaging, and its relative illumination is low, and the edge image is dark, which affects image viewing. At the same time, traditional day and night confocal lenses usually use special materials (such as low-dispersion glass) and complex processes, resulting in high manufacturing costs. Summary of the Invention

[0004] The present application provides a day and night confocal hyper-reflective lens and an image acquisition device to at least solve the above technical problems existing in the prior art.

[0005] On the one hand, an embodiment of the present application provides a day-night confocal refracting metalens, which has consistent focus in the visible light band and the infrared band. The lens includes six lenses arranged in sequence from the object plane to the image plane along the optical axis, at least one of which is a metasurface lens, and the remaining lenses are non-metasurface lenses.

[0006] The lens meets the following requirements:

[0007]

[0008] Among them, Mis the thickness of the metasurface substrate of the day-night confocal refracting metalens, TTL is the total length of the optical system, and M0 is the MTF value of the central field of view.

[0009] In one embodiment, the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the optical axis from the object plane to the image plane, at least one of which is a metasurface lens, and the remaining lenses are spherical and aspherical lenses.

[0010] In one embodiment, the sixth lens is a metasurface lens, the first lens, the third lens, the fourth lens, and the fifth lens are spherical lenses, and the second lens is an aspherical lens.

[0011] In one embodiment, the third lens and the fourth lens are cemented lenses.

[0012] In one embodiment, the first lens is a lens with positive optical power, whose object side surface is convex and the image side surface is concave; the object side surface and the image side surface of the first lens are both spherical; the second lens is a lens with negative optical power, whose object side surface is convex and the image side surface is concave, and the object side surface and the image side surface of the second lens are both aspherical; the third lens is a spherical lens with negative optical power, whose object side surface is concave and the image side surface is concave, and the object side surface and the image side surface of the third lens are both spherical; the fourth lens is a spherical lens with positive optical power, whose object side surface is convex and the image side surface is convex; the object side surface and the image side surface of the fourth lens are both spherical; the fifth lens is a lens with positive optical power, whose object side surface is convex and the image side surface is concave, and the object side surface and the image side surface of the fifth lens are both spherical; the sixth lens is a metasurface lens, whose object side surface is flat and the image side surface has a microstructure arrangement.

[0013] In one embodiment, the distance from the center of the optical axis of the object side of the first lens to the object plane is L, where L is ≥ 0.3 m.

[0014] In one embodiment, the center field MTF value of the lens is M0, where M0 ≥ 0.7@60lp / mm.

[0015] In one embodiment, the maximum lens aperture D of the lens satisfies: D≤8.0 mm.

[0016] In one possible implementation manner, the relative illumination RI of the lens satisfies: RI≥70%.

[0017] In one possible implementation manner, the field of view (Fov) of the lens satisfies: Fov ≥ 70°.

[0018] In one embodiment, a stop is further included.

[0019] Another aspect of an embodiment of the present application provides an image acquisition device, comprising any one of the day-night confocal refracting super lens and an image sensor as described in claims 1-11.

[0020] In one embodiment, the lens has focus consistency in the visible light band and the infrared band, and is used to generate clear images without focusing in a day-night environment; the device is suitable for an in-vehicle driving assistance system or a security monitoring system.

[0021] Compared with the prior art, this application has the following advantages:

[0022] 1. The lens of this application adopts a technical solution that combines a metasurface lens with a traditional lens, which reduces the volume and weight of the lens of the optical system, facilitates integration into the day and night confocal system, and realizes a miniaturized, lightweight, and integrated design;

[0023] 2. This application utilizes superlens technology to achieve high imaging resolution in both visible and infrared light bands, thus realizing high-resolution imaging;

[0024] 3. The technical solution of refractive-supermixing in this application can improve the relative illumination of the optical system, enhance the edge image clarity, and facilitate image viewing;

[0025] 4. The manufacturing process of the super surface in this application is relatively simple, and conventional photolithography, etching, sputtering, spraying and other methods can be used, with low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of the day and night confocal refracting metalens in Examples 1 and 2 of the present application;

[0027] Figure 2 Schematic diagram of the MTF of the day-night confocal refracting super lens in Example 1 of the present application;

[0028] Figure 3 Schematic diagram of the diffuse spots of the day-night confocal refracting hyperlens in Example 1 of the present application;

[0029] Figure 4 Schematic diagram of relative illumination of the day and night confocal refracting super lens in Example 1 of the present application;

[0030] Figure 5 Schematic diagram of the MTF of the day-night confocal refracting super lens in Example 2 of the present application;

[0031] Figure 6 Schematic diagram of the diffuse spots of the day-night confocal refracting hyperlens in Example 2 of the present application;

[0032] Figure 7 Schematic diagram of relative illumination of the day and night confocal refracting hyperlens in Example 2 of the present application;

[0033] Description of reference numerals:

[0034] 110 , first lens; 120 , second lens; 130 , aperture; 140 , third lens; 150 , fourth lens; 160 , fifth lens; 170 , sixth lens; 180 , protective window; 190 , imaging surface. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below with reference to the accompanying drawings.

[0036] In the description of this application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0037] Metasurfaces are composed of periodic or non-periodic micro-nanostructures (such as nanopillars and nanoholes), the size of which is much smaller than the wavelength of light. By adjusting the shape, size and arrangement of the micro-nanostructures, the phase, amplitude and polarization of the light wave can be precisely controlled. Metasurface technology has broken through the limitations of traditional optics and provided a new path for the miniaturization, multifunctionality and high performance of optical devices. Through optimized design, metasurfaces can operate in the ultraviolet, visible, infrared and even terahertz bands, and can effectively correct aberrations to provide high-quality imaging effects. Metasurfaces can be mass-produced using mature semiconductor manufacturing processes (such as photolithography and etching), which has the advantage of low cost. With the advancement of manufacturing technology, the manufacturing cost of metasurfaces is expected to be further reduced. Based on the above advantages, metasurfaces have broad application prospects in imaging, display, communication, sensing and other fields, and are expected to promote revolutionary development of optical technology in the future.

[0038] The folding-meta hybrid system formed by combining metasurface lenses with traditional lenses can effectively solve the problems existing in traditional day and night confocal lenses. The folding-meta hybrid system can usually realize light path folding, thereby achieving the required light path length in a relatively small optical system, while reducing the lens size, which helps to reduce the volume and weight of the optical system. In the visible light and infrared light bands, its imaging resolution and relative illumination are relatively high, which can achieve high-quality imaging, while having a low manufacturing cost.

[0039] This application discloses a day-night confocal refracting metalens with consistent focus in the visible and infrared bands. The lens comprises six lenses arranged sequentially along the optical axis from the object plane to the image plane, at least one of which is a metasurface lens, and the remaining lenses are non-metasurface lenses.

[0040] The lens of the embodiment of the present application satisfies the following formula:

[0041]

[0042] Among them, M is the thickness of the metasurface substrate of the day-night confocal refracting metalens, TTL is the total length of the optical system, and M0 is the MTF value of the central field of view.

[0043] In some embodiments, the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the optical axis from the object plane to the image plane, at least one of which is a metasurface lens, and the remaining lenses are spherical and aspherical lenses.

[0044] In a preferred embodiment, the sixth lens is a metasurface lens, the first lens, the third lens, the fourth lens, and the fifth lens are spherical lenses, and the second lens is an aspherical lens.

[0045] In this embodiment, the metasurface lens consists of a substrate and a micro-nanostructure mounted on the substrate. This micro-nanostructure is composed of an array of subwavelength-scale micro-nanounits, each with a specific shape, size, and arrangement to precisely control the phase, amplitude, or polarization state of the incident light wave. Through the design of these micro-nanostructures, the metasurface lens achieves optical performance comparable to or even superior to that of traditional lenses, such as high transmittance, low chromatic aberration, and low distortion, while maintaining a lightweight and thin design.

[0046] As a feasible implementation, the first, third, fourth, and fifth lenses are made of glass, the second lens is made of resin, the sixth lens's substrate material includes, but is not limited to, amorphous silicon, crystalline silicon, borosilicate, silicon dioxide, quartz, and glass, and the sixth lens's micro-nanostructure material includes, but is not limited to, amorphous silicon, crystalline silicon, silicon dioxide, silicon nitride, and titanium dioxide. By coordinating the materials and optical power of each lens, an athermal design is achieved, reducing both material costs and system size.

[0047] In a preferred embodiment, the third lens and the fourth lens are cemented lenses.

[0048] Further, in some embodiments, the first lens is a lens with positive optical power, whose object side surface is convex and the image side surface is concave; both the object side surface and the image side surface of the first lens are spherical; the second lens is a lens with negative optical power, whose object side surface is convex and the image side surface is concave, and both the object side surface and the image side surface of the second lens are aspherical; the third lens is a spherical lens with negative optical power, whose object side surface is concave and the image side surface is concave, and both the object side surface and the image side surface of the third lens are spherical; the fourth lens is a spherical lens with positive optical power, whose object side surface is convex and the image side surface is convex; both the object side surface and the image side surface of the fourth lens are spherical; the fifth lens is a lens with positive optical power, whose object side surface is convex and the image side surface is concave, and both the object side surface and the image side surface of the fifth lens are spherical; the sixth lens is a metasurface lens, whose object side surface is flat and the image side surface has a microstructure arrangement.

[0049] In some embodiments, the distance from the center of the optical axis of the object-side surface of the first lens to the object plane is L, where L is ≥ 0.3 m.

[0050] Based on the above solution, the MTF value of the center field of view of the lens is M0, where M0 ≥ 0.7@60lp / mm.

[0051] Based on the above solution, the maximum lens aperture D of the lens satisfies: D≤8.0mm.

[0052] Based on the above solution, the relative illumination RI of the lens satisfies: RI ≥ 70%.

[0053] In some embodiments, the field of view (Fov) of the lens satisfies: Fov ≥ 70°.

[0054] In a preferred embodiment, any of the above lenses includes an aperture, which is disposed before the first lens, after the sixth lens, or between any two lenses.

[0055] This application exemplarily provides two day and night confocal folded metal lenses that meet usage requirements in two embodiments. The day and night confocal folded metal lenses provided by the two specific embodiments of this application are introduced in detail below.

[0056] Example 1

[0057] For example, Table 1 describes in detail the specific optical data parameters of each lens in the day and night confocal refracting lens provided by the embodiment of the present invention in a feasible implementation manner. The optical data parameters in Table 1 correspond to Figure 1 The day-night confocal folding metalens is shown.

[0058] Figure 1 This is a schematic diagram of the structure of a day and night confocal refracting metal lens at room temperature provided by an embodiment of the present invention. Figure 1As shown, the day-night confocal refracting hyperlens provided by the embodiment of the present invention includes a first lens 110, a second lens 120, an aperture 130, a third lens 140, a fourth lens 150, a fifth lens 160, and a sixth lens 170, which are arranged in sequence along the optical axis from the object plane to the image plane.

[0059] The incident light enters through the object side of the first lens 110 , passes through the second lens 120 , and then passes through the aperture 130 , the third lens 140 , the fourth lens 150 , the fifth lens 160 , and the sixth lens 170 , passes through the protective window 180 , and finally converges on the imaging surface 190 .

[0060] At the same time, set the lens to meet The optical lens size of the day and night confocal refractive index lens is small, and the maximum lens effective aperture meets D≤8.0mm. The resolution of visible light and infrared light of the day and night confocal refractive index lens is relatively high, and the imaging quality of the central field of view meets M0≥0.7@60lp / mm, while the relative illumination meets RI≥70%.

[0061] Among them, the first lens 110 is a lens with positive optical power, whose object-side surface is convex; the second lens 120 is a lens with negative optical power, whose object-side surface is convex, and both the object-side and image-side surfaces are aspherical; the third lens 140 is a spherical lens with negative optical power, whose object-side surface is concave, and whose image-side surface is concave; the fourth lens 150 is an aspherical lens with positive optical power, whose object-side surface is convex, and whose image-side surface is convex; the fifth lens 160 is a spherical lens with positive optical power, whose object-side and image-side surfaces are both spherical; the sixth lens 170 is a metasurface lens; the third lens 140 and the fourth lens 150 are doublet lenses; the aperture 130 is located after the second lens 120.

[0062] Table 1

[0063]

[0064]

[0065] Among them, the surface numbers are numbered according to the order of the surfaces of each lens. For example, surface number 1 represents the object surface, surface number 2 represents the object side surface of the first lens 110, surface number 3 represents the image side surface of the first lens 110, and so on. Among them, the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "Infinity" represents that the surface is flat. The spacing represents the axial distance from the center of the current surface to the next surface. The units of the curvature radius and spacing are both millimeters (mm).

[0066] Its even-order aspheric surface satisfies the following equation:

[0067]

[0068] Where z is the distance from the vertex of the even-order aspheric surface along the optical axis, r is the height from the optical axis, c is the curvature 1 / R, R is the radius of curvature at the vertex of the lens; k is the cone coefficient -e2, and a2, a3, a4, a5, and a6 are the higher-order coefficients of the aspheric surface.

[0069] For example, Table 2 describes in detail the conic coefficient k and the higher-order coefficients a2, a3, a4, a5, and a6 of the aspheric lens surface in this embodiment in a feasible implementation manner.

[0070] Table 2

[0071] Surface number a2 a3 a4 a5 a6 4 8.22E-003 5.17E-006 4.18E-006 5.43E-005 7.23E-007 5 3.69E-003 4.16E-003 6.05E-003 7.25E-005 9.69E-003

[0072] Among them, 8.22E-003 means that the coefficient a2 of surface number 4 is 8.22E-003, and so on.

[0073] Exemplarily, Table 3 details the phase of the metasurface in this embodiment in a feasible implementation manner.

[0074] Table 3

[0075] Surface number R1 A1 A2 A3 A4 A5 13 1 4.25E+001 3.98E+000 1.05E-001 5.30E-002 7.64E-003

[0076] Where R1 is the normalized radius of the binary surface.

[0077] In this embodiment, the relationship between the thickness of the metasurface substrate, the total optical length and the central field of view MTF satisfies The optical object distance satisfies L = 0.65m; the central field MTF value satisfies M0 = 0.785@60lp / mm; the maximum lens effective aperture satisfies D = 6.49mm; the field of view angle satisfies Fov = 74.2°;

[0078] The working band of the day and night confocal lens provided in this embodiment is visible light 436-656nm and infrared light 940nm, Fno is 2.2, and visible light and infrared light are confocal, which meets the use requirements of the day and night confocal lens.

[0079] Figure 2 This is a schematic diagram of the MTF of the day-night confocal lens provided by an embodiment of the present invention. The day-night confocal lens provided by an embodiment of the present invention has high resolution and can meet the high-quality imaging requirements of day and night confocal.

[0080] Figure 3 Schematic diagram of the diffuse spot of the day-night confocal lens provided by an embodiment of the present invention. The day-night confocal refracting metalens provided by an embodiment of the present invention has a relatively concentrated and evenly distributed diffuse pattern over the entire long-wavelength band, which can meet the requirements of high-resolution imaging.

[0081] Figure 4 This is a schematic diagram of the relative illumination of the day and night confocal lens provided by an embodiment of the present invention, which represents the relative illumination values corresponding to different fields of view, such as Figure 4 As shown, the day and night confocal lens provided by the embodiment of the present invention has a relative illumination greater than 70% in the entire field of view in the working band, and the brightness is uniform.

[0082] Example 2

[0083] For example, Table 4 describes in detail the specific optical data parameters of each lens in the day and night confocal refractive index lens provided by the embodiment of the present invention in a feasible implementation manner. The optical data parameters in Table 4 correspond to Figure 1 The day-night confocal folding metalens is shown.

[0084] Figure 1 This is a schematic diagram of the structure of a day and night confocal refracting metal lens at room temperature provided by an embodiment of the present invention. Figure 1 As shown, the day-night confocal refracting hyperlens provided by the embodiment of the present invention includes a first lens 110, a second lens 120, an aperture 130, a third lens 140, a fourth lens 150, a fifth lens 160, and a sixth lens 170, which are arranged in sequence along the optical axis from the object plane to the image plane.

[0085] The incident light enters through the object side of the first lens 110 , passes through the second lens 120 , and then passes through the aperture 130 , the third lens 140 , the fourth lens 150 , the fifth lens 160 , and the sixth lens 170 , passes through the protective window 180 , and finally converges on the imaging surface 190 .

[0086] At the same time, set the lens to meet The optical lens size of the day and night confocal refractive metal lens is small, and the maximum lens effective aperture meets D≤8.0mm. The resolution of visible light and infrared light of the day and night confocal refractive metal lens is relatively high. The imaging quality of the central field of view meets M0≥0.7@60lp / mm, and the relative illumination meets RI≥70%.

[0087] Among them, the first lens 110 is a lens with positive optical power, whose object-side surface is convex; the second lens 120 is a lens with negative optical power, whose object-side surface is convex, and both the object-side and image-side surfaces are aspherical; the third lens 140 is a spherical lens with negative optical power, whose object-side surface is concave, and whose image-side surface is concave; the fourth lens 150 is an aspherical lens with positive optical power, whose object-side surface is convex, and whose image-side surface is convex; the fifth lens 160 is a spherical lens with positive optical power, whose object-side and image-side surfaces are both spherical; the sixth lens 170 is a metasurface lens; the third lens 140 and the fourth lens 150 are doublet lenses; the aperture 130 is located after the second lens 120.

[0088] Table 4

[0089] Surface number Face shape Curvature radius (mm) Spacing (mm) Material Semi-diameter (mm) 1OBJECT Standard Infinity 10000.00 7567.08 2 Standard 7.13 0.75 Glass 3.12 3 Standard 29.66 0.006 3.96 4 EvenAsphere 5.05 1.25 resin 2.32 5 EvenAsphere 1.07 0.80 1.32 6STOP Standard Infinity 0.04 2.07 7 Standard -16.56 0.49 Glass 1.08 8 Standard 14.33 2.61 Glass 1.42 9 Standard -5.88 0.16 2.30 10 Standard 5.85 1.99 Glass 3.03 11 Standard 8.33 0.99 2.93 12 Standard Infinity 1.10 Glass 3.00 13 Binary2 Infinity 0.45 4.19 14 Standard Infinity 0.40 Glass 3.32 15 Standard Infinity 1.47 3.39 16IMAGE Standard Infinity - 3.79

[0090] Among them, the surface numbers are numbered according to the order of the surfaces of each lens. For example, surface number 1 represents the object surface, surface number 2 represents the object side surface of the first lens 110, surface number 3 represents the image side surface of the first lens 110, and so on. Among them, the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the image side, and a negative value represents that the surface is curved toward the object side. "Infinity" represents that the surface is flat. The spacing represents the axial distance from the center of the current surface to the next surface. The units of the curvature radius and spacing are both millimeters (mm).

[0091] Its even-order aspheric surface satisfies the following equation:

[0092]

[0093] Where z is the distance from the vertex of the even-order aspheric surface along the optical axis, r is the height from the optical axis, c is the curvature 1 / R, R is the radius of curvature at the vertex of the lens; k is the cone coefficient -e2, and a2, a3, a4, a5, and a6 are the higher-order coefficients of the aspheric surface.

[0094] For example, Table 5 describes in detail the conic coefficient k and the higher-order coefficients a2, a3, a4, a5, and a6 of the aspheric lens surface in this embodiment in a feasible implementation manner.

[0095] Table 5

[0096] Surface number a2 a3 a4 a5 a6 4 5.76E-003 3.11E-004 3.51E-005 3.43E-005 1.38E-006 5 8.01E-003 6.38E-003 6.81E-003 4.20E-004 1.43E-003

[0097] Among them, 5.76E-003 means that the coefficient a2 of surface number 4 is 5.76E-003, and so on.

[0098] Exemplarily, Table 6 details the phase of the metasurface in this embodiment in a feasible implementation manner.

[0099] Table 6

[0100] Surface number R1 A1 A2 A3 A4 A5 13 1 9.68E+001 2.07E+000 7.57E-003 3.94E-002 1.68E-003

[0101] Where R1 is the normalized radius of the binary surface.

[0102] The thickness of the metasurface substrate, the total optical length and the central field of view MTF meet the requirements. The optical object distance satisfies L = 10.00m; the central field MTF value satisfies M0 = 0.802@60lp / mm; the maximum lens effective aperture satisfies D = 6.38mm; the field of view angle satisfies Fov = 74.2°;

[0103] The working band of the day and night confocal lens provided in this embodiment is visible light 436-656nm and infrared light 940nm, Fno is 2.2, and visible light and infrared light are confocal, which meets the use requirements of the day and night confocal lens.

[0104] Figure 5 This is a schematic diagram of the MTF of the day-night confocal lens provided by an embodiment of the present invention. The day-night confocal lens provided by an embodiment of the present invention has high resolution and can meet the high-quality imaging requirements of day and night confocal.

[0105] Figure 6 Schematic diagram of the diffuse spot of the day-night confocal lens provided by an embodiment of the present invention. The day-night confocal refracting metalens provided by an embodiment of the present invention has a relatively concentrated and evenly distributed diffuse pattern over the entire long-wavelength band, which can meet the requirements of high-resolution imaging.

[0106] Figure 7 This is a schematic diagram of the relative illumination of the day and night confocal lens provided by an embodiment of the present invention, which represents the relative illumination values corresponding to different fields of view, such as Figure 7 As shown, the day and night confocal lens provided by the embodiment of the present invention has a relative illumination greater than 73% in the entire field of view in the working band, and the brightness is uniform.

[0107] In summary, the day-night confocal lens provided by the embodiment of the present invention has a small size, low cost, high relative illumination, and clear imaging, and can meet the requirements of high-quality imaging and lightweight integration.

[0108] Example 1 and Example 2 respectively satisfy the relationship shown in Table 7 below:

[0109] Table 7

[0110]

[0111] This application also discloses an image acquisition device comprising any of the aforementioned day / night confocal refracting metal lenses and an image sensor. The day / night confocal refracting metal lens has consistent focus in both the visible and infrared bands, enabling it to produce clear images without focusing in day / night environments. The image acquisition device is suitable for use in vehicle-mounted driver assistance systems or security monitoring systems.

[0112] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A day and night confocal refracting metalens, characterized in that: The lens has consistent focus in the visible light band and the infrared band, and includes six lenses arranged in sequence from the object plane to the image plane along the optical axis, at least one of which is a metasurface lens, and the remaining lenses are non-metasurface lenses; The lens meets the following requirements: Among them, M is the thickness of the metasurface substrate of the day-night confocal refracting metalens, TTL is the total length of the optical system, and M0 is the MTF value of the central field of view.

2. The day and night confocal refracting metalens according to claim 1, characterized in that: The lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along the optical axis from the object plane to the image plane, wherein at least one lens is a metasurface lens, and the remaining lenses are spherical lenses and aspherical lenses.

3. The day / night confocal refracting metalens according to claim 2, characterized in that: The sixth lens is a metasurface lens, the first lens, the third lens, the fourth lens, and the fifth lens are spherical lenses, and the second lens is an aspherical lens.

4. The day / night confocal refracting metalens according to claim 3, characterized in that: The third lens and the fourth lens are cemented lenses.

5. The day / night confocal refracting metalens according to claim 3, characterized in that: The first lens is a lens with positive refractive power, the object side surface of which is convex and the image side surface of which is concave; both the object side surface and the image side surface of the first lens are spherical surfaces; The second lens is a lens with negative optical power, the object side surface of which is convex and the image side surface is concave, and both the object side surface and the image side surface of the second lens are aspherical; The third lens is a spherical lens with negative optical power, the object side surface of which is concave, and the image side surface of which is concave, and both the object side surface and the image side surface of the third lens are spherical; The fourth lens is a spherical lens with positive optical power, the object side surface of which is convex, and the image side surface of which is convex; both the object side surface and the image side surface of the fourth lens are spherical surfaces; The fifth lens is a lens with positive refractive power, the object side surface of which is convex and the image side surface is concave, and both the object side surface and the image side surface of the fifth lens are spherical; The sixth lens is a metasurface lens, the object side of which is a plane and the image side of which has a microstructure arrangement.

6. The day and night confocal refracting metalens according to claim 2, characterized in that: The distance from the center of the optical axis of the object side surface of the first lens to the object plane is L, where L is ≥ 0.3 m.

7. The day and night confocal refracting metalens according to claim 1, characterized in that: The center field MTF value of the lens is M0, where M0 ≥ 0.7@60lp / mm.

8. The day and night confocal refracting metalens according to claim 1, characterized in that: The maximum lens aperture D of the lens satisfies: D≤8.0mm.

9. The day and night confocal refracting metalens according to claim 1, characterized in that: The relative illumination RI of the lens satisfies: RI≥70%.

10. The day and night confocal refracting metalens according to claim 1, characterized in that: The field of view (Fov) of the lens satisfies: Fov ≥ 70°.

11. The day-night confocal refracting metalens according to claim 1, characterized in that: Also includes the aperture.

12. An image acquisition device, characterized in that: The invention comprises any one of the day and night confocal refracting metalens and image sensor as described in claims 1 to 11.

13. The image acquisition device according to claim 12, characterized in that: The lens has consistent focus in the visible light band and the infrared band, and is used to generate clear images without focusing in a day-night environment; The device is suitable for an on-vehicle driving assistance system or a security monitoring system.

Images