Refraction and diffraction hybrid vehicle-mounted lens and camera device with same

Abstract

The invention discloses a refraction and diffraction hybrid vehicle-mounted lens and a camera device with the same, the lens comprises a first lens and a second lens which are sequentially arranged from an object side to an image side along an optical axis direction, the first lens or the second lens is a diffraction lens, the first lens has positive or negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has positive focal power, and the image side surface of the second lens is a convex surface. According to the invention, a binary optical technology is innovatively introduced, the first lens is designed to be a diffraction lens and the image side surface of the first lens is a binary diffraction surface, or the second lens is designed to be a diffraction lens and the object side surface of the second lens is a binary diffraction surface, only two lenses are adopted, a back focus drift phenomenon is effectively controlled in a wide temperature range of-40 DEG C to + 85 DEG C, and the imaging quality is improved. The requirement for clear imaging is met, double optimization of cost and assembly efficiency is achieved, the total optical length of the lens is controlled within 7 mm, the aperture reaches 1 / 2, the optical performance is further improved, and a new thought is provided for wide application of an optical system.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical lenses, and particularly relates to a refractive-diffractive hybrid vehicle-mounted lens and an imaging device having the same. Background Art

[0002] With the increasing maturity of intelligent driving technology, vehicle-mounted optical lenses have completed the technological leap from single perception to global integration. Their application scenarios have achieved full coverage, their core optical parameters have completed standardized iteration, and the product form has entered the stage of platform development. Under this technical background, the innovation focus of vehicle manufacturers is undergoing a strategic transformation from parameter breakthroughs to system-level optimization. The industry competition dimension has been upgraded to the collaborative construction of the full-cycle cost control and zero-defect quality system, driving the industrial chain to evolve towards a lean and highly reliable ecological closed-loop.

[0003] Currently, the disclosed designs of vehicle-mounted optical lenses on the market are all based on the principle of refractive imaging. In order to effectively eliminate chromatic aberration and expand the field of view angle, the industry mainstream solutions generally adopt a compound optical path structure of multiple lenses (3-7 lenses). However, with the increase in the number of lenses, the processing and assembly difficulty of the lens also increases accordingly, and it is also not conducive to realizing the thin and light design of the lens. The limitations of this technical path have become the core technical barriers restricting the breakthrough of vehicle-mounted optical lenses to higher performance dimensions. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a refractive-diffractive hybrid vehicle-mounted lens and an imaging device having the same.

[0005] In order to achieve the above purpose and reach the above technical effects, the technical solution adopted by the present invention is as follows:

[0006] A refractive-diffractive hybrid vehicle-mounted lens includes a first lens and a second lens arranged in sequence along the optical axis direction from the object side towards the image side. The first lens or the second lens is a diffractive lens. The first lens has positive or negative optical power, its object side surface is convex, and its image side surface is concave. The second lens has positive optical power, and its image side surface is convex.

[0007] Further, the image side surface of the first lens is a binary diffractive surface.

[0008] Further, the object side surface of the second lens is a binary diffractive surface.

[0009] Further, the object side surface of the second lens is concave or convex.

[0010] Further, the first lens satisfies the following conditions:

[0011] 0.61 ≤ 2*D1 / f ≤ 0.66;

[0012] Among them, 2*D1 is the effective diameter of the first lens, and f is the overall focal length value of the lens.

[0013] Furthermore, the refractive index Nd1 of the first lens satisfies 1.54 ≤ Nd1 ≤ 1.66, and the Abbe number Vd1 of its material satisfies 20.4 ≤ Vd1 ≤ 56; the refractive index Nd2 of the second lens satisfies 1.54 ≤ Nd2 ≤ 1.66, and the Abbe number Vd2 of its material satisfies 20.4 ≤ Vd2 ≤ 56.

[0014] Furthermore, the refractive-diffractive hybrid vehicle-mounted lens satisfies the following conditions:

[0015] -4.8 ≤ f1 / f ≤ 3.32;

[0016] 0.90 ≤ f2 / f ≤ 1.83;

[0017] Among them, f1 and f2 are the focal lengths of the first lens and the second lens respectively, and f is the overall focal length value of the lens.

[0018] Furthermore, the refractive-diffractive hybrid vehicle-mounted lens satisfies the following conditions:

[0019] 6.57 ≤ FOV / Ym / 2 ≤ 6.85;

[0020] Among them, FOV is the horizontal or maximum lens field of view angle, and Ym is the image height corresponding to the field of view angle FOV.

[0021] Furthermore, the refractive-diffractive hybrid vehicle-mounted lens satisfies the following conditions:

[0022] 1.51 ≤ TTL / f ≤ 1.65;

[0023] Among them, TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the lens on the optical axis, and f is the overall focal length value of the lens.

[0024] Furthermore, the refractive-diffractive hybrid vehicle-mounted lens satisfies the following conditions:

[0025] 4.24 ≤ Y1*180 / pi;

[0026] Among them, Y1 is the lens image height corresponding to the half field of view angle of 1°, and pi is the circumference ratio.

[0027] Furthermore, the refractive-diffractive hybrid vehicle-mounted lens satisfies the following conditions:

[0028] BFL / TTL > 0.31;

[0029] Among them, BFL is the distance from the center of the image side surface of the second lens to the imaging surface of the lens on the optical axis, and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the lens on the optical axis.

[0030] The present invention also discloses a camera device, including an electronic photosensitive element and a diffractive-refractive hybrid vehicle-mounted lens as described above.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The present invention discloses a diffractive-refractive hybrid vehicle-mounted lens and a camera device having the same. The binary optical technology is innovatively introduced, and the unique thermally induced deformation characteristic of the diffractive optical element is creatively utilized. This characteristic has a weak correlation with the refractive index change of the substrate material. By introducing an aspherical-diffractive composite surface type design, the replacement of 1-2 traditional spherical lenses is realized. Only two lenses are required. In the wide temperature range of -40°C to +85°C, the phenomenon of back focal drift is effectively controlled, meeting the requirements of clear imaging. And the optical path of the system is shortened to 2 / 3 of the traditional scheme. On the premise of ensuring the imaging quality, the cost problem is solved, the material cost is reduced by 30%-45% compared with the traditional structure, and the axial dimension of the lens is reduced by more than 30%, realizing the lightweight design of the optical lens, providing strong support for the miniaturization and integration of the optical system, and greatly reducing the assembly difficulty. The tolerance accumulation effect during the assembly process is greatly reduced compared with the traditional scheme, and the process tolerance window is expanded to ±15μm, increasing the mass production yield rate to more than 95%. At the same time, the overall optical length of the lens is controlled within 7mm, and the aperture reaches 1 / 2, further improving the optical performance, having excellent industrial implementation prospects, and providing new ideas for the wide application of the optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention;

[0034] Figure 2 It is the field curvature curve of Embodiment 1 of the present invention;

[0035] Figure 3 It is the distortion curve of Embodiment 1 of the present invention;

[0036] Figure 4 It is the MTF VS Field curve graph of Embodiment 1 of the present invention;

[0037] Figure 5 It is the relative illumination curve of the lens of Embodiment 1 of the present invention under the Y field of view;

[0038] Figure 6 It is the temperature analysis curve of the lens of Embodiment 1 of the present invention in a -40°C temperature environment;

[0039] Figure 7 It is the temperature analysis curve of the lens of Embodiment 1 of the present invention in a 20°C temperature environment;

[0040] Figure 8 Temperature analysis curve of the lens of Embodiment 1 of the present invention at a temperature environment of 85°C;

[0041] Figure 9 Schematic structural diagram of Embodiment 2 of the present invention;

[0042] Figure 10 Field curvature curve of Embodiment 2 of the present invention;

[0043] Figure 11 Distortion curve of Embodiment 2 of the present invention;

[0044] Figure 12 MTF VS Field curve graph of Embodiment 2 of the present invention;

[0045] Figure 13 Relative illuminance curve of the lens of Embodiment 2 of the present invention under the Y field of view;

[0046] Figure 14 Temperature analysis curve of the lens of Embodiment 2 of the present invention at a temperature environment of -40°C;

[0047] Figure 15 Temperature analysis curve of the lens of Embodiment 2 of the present invention at a temperature environment of 20°C;

[0048] Figure 16 Temperature analysis curve of the lens of Embodiment 2 of the present invention at a temperature environment of 85°C;

[0049] Figure 17 Schematic structural diagram of Embodiment 3 of the present invention;

[0050] Figure 18 Field curvature curve of Embodiment 3 of the present invention;

[0051] Figure 19 Distortion curve of Embodiment 3 of the present invention;

[0052] Figure 20 MTF VS Field curve graph of Embodiment 3 of the present invention;

[0053] Figure 21 Relative illuminance curve of the lens of Embodiment 3 of the present invention under the Y field of view;

[0054] Figure 22 Temperature analysis curve of the lens of Embodiment 3 of the present invention at a temperature environment of -40°C;

[0055] Figure 23 Temperature analysis curve of the lens of Embodiment 3 of the present invention at a temperature environment of 20°C;

[0056] Figure 24 This is the temperature analysis curve of the lens in Embodiment 3 of the present invention under a temperature environment of 85°C. Detailed implementation manners

[0057] The present invention will be elaborated in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0058] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to attempt to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description to follow.

[0059] As Figure 1-24 shown, a refractive-diffractive hybrid vehicle-mounted lens includes a first lens 1, a diaphragm 2, a second lens 3, a filter 4, and an image plane IMA 5 that are sequentially arranged along the optical axis direction from the object side to the image side.

[0060] The present invention introduces binary optical technology. The first lens 1 can be designed as a diffractive lens and the image side surface of the first lens 1 can be a binary diffractive surface, or the second lens 3 can be designed as a diffractive lens and the object side surface of the second lens 3 can be a binary diffractive surface. Compared with traditional optical technology, diffractive lenses exhibit significant advantages: thinner thickness, lighter weight, and higher design flexibility. These characteristics provide strong support for the miniaturization and integration of optical systems.

[0061] Among the two lenses (the first and second lenses) of the present invention, the lens with the largest optical power adopts a plastic material with a refractive index temperature coefficient dn / dt not greater than -3.35*10 -5 plastic material.

[0062] The first lens 1 has positive or negative optical power. Its object side surface is convex and its image side surface is concave. The first lens 1 is meniscus-shaped, which is beneficial for collecting light, reducing distortion, and improving imaging quality.

[0063] The second lens 3 has positive optical power, and its image side surface is convex.

[0064] The diaphragm 2 is arranged between the first lens 1 and the second lens 3, which is beneficial for reducing assembly sensitivity, reducing aberration, and also beneficial for reducing the lens aperture, so as to keep the picture clear within the temperature range of -40°C to +85°C.

[0065] In some implementation manners, the object side surface of the second lens 3 is concave or convex.

[0066] In some embodiments, the first lens 1 satisfies the following conditions:

[0067] 0.61 ≤ 2*D1 / f ≤ 0.66;

[0068] where 2*D1 is the effective diameter of the first lens 1, and f is the overall focal length value of the lens.

[0069] In some embodiments, the refractive index Nd1 of the first lens 1 satisfies 1.54 ≤ Nd1 ≤ 1.66, and the Abbe number Vd1 of its material satisfies 20.4 ≤ Vd1 ≤ 56.

[0070] In some embodiments, the refractive index Nd2 of the second lens 3 satisfies 1.54 ≤ Nd2 ≤ 1.66, and the Abbe number Vd2 of its material satisfies 20.4 ≤ Vd2 ≤ 56.

[0071] In some embodiments, the diffractive-refractive hybrid vehicle-mounted lens satisfies the following conditions:

[0072] -4.8 ≤ f1 / f ≤ 3.32;

[0073] 0.90 ≤ f2 / f ≤ 1.83;

[0074] where f1 and f2 are the focal lengths of the first lens 1 and the second lens 3 respectively, and f is the overall focal length value of the lens. By reasonably matching the focal lengths of the lenses, it is beneficial to reduce the assembly sensitivity, so that within the temperature range of -40°C to +85°C, the back focal drift is controlled within a very small range, meeting the requirements for clear imaging.

[0075] In some embodiments, the diffractive-refractive hybrid vehicle-mounted lens satisfies the following conditions:

[0076] 6.57 ≤ FOV / Ym / 2 ≤ 6.85;

[0077] where FOV is the horizontal or maximum lens field of view angle, and Ym is the image height corresponding to the field of view angle FOV.

[0078] In some embodiments, the diffractive-refractive hybrid vehicle-mounted lens satisfies the following conditions:

[0079] 1.51 ≤ TTL / f ≤ 1.65;

[0080] where TTL is the distance from the center of the object side surface of the first lens 1 to the imaging surface of the lens on the optical axis, and f is the overall focal length value of the lens.

[0081] In some embodiments, the diffractive-refractive hybrid vehicle-mounted lens satisfies the following conditions:

[0082] 4.24 ≤ Y1*180 / pi;

[0083] Wherein, Y1 is the image height of the lens corresponding to a half field of view angle of 1°, and pi is the pi.

[0084] In some embodiments, the refractive-diffractive hybrid vehicle-mounted lens satisfies the following conditions:

[0085] BFL / TTL > 0.31;

[0086] Wherein, BFL is the distance from the center of the image side of the second lens 3 to the imaging surface of the lens on the optical axis, and TTL is the distance from the center of the object side of the first lens 1 to the imaging surface of the lens on the optical axis. Further, BFL / TTL > 0.38, which is beneficial to increasing the optical back focal length of the lens and leaving sufficient space for the module.

[0087] The present invention also discloses an imaging device, including an electronic photosensitive element and a refractive-diffractive hybrid vehicle-mounted lens as described above.

[0088] Embodiment 1

[0089] As Figure 1-8 shown, a refractive-diffractive hybrid vehicle-mounted lens includes a first lens 1, a diaphragm 2, a second lens 3, a filter 4, and an image plane IMA 5 arranged in sequence along the optical axis direction from the object side to the image side.

[0090] In this embodiment, the binary optical technology is introduced, and the first lens 1 is designed as a diffractive lens, and the image side of the first lens 1 is a binary diffractive surface. Compared with the traditional optical technology, the diffractive lens shows significant advantages: thinner thickness, lighter weight, and higher design flexibility, which provide strong support for the miniaturization and integration of the optical system.

[0091] The first lens 1 has a negative optical power, its object side is convex, its image side is concave, and the first lens 1 is crescent-shaped, which is beneficial to collecting light, reducing distortion, and improving imaging quality.

[0092] The second lens 3 has a positive optical power, and its image side is convex.

[0093] The diaphragm 2 is arranged between the first lens 1 and the second lens 3, which is beneficial to reducing the assembly sensitivity, reducing aberration, and also beneficial to reducing the lens aperture, so as to keep the picture clear within the temperature range of -40°C to +85°C.

[0094] The specific parameters of each lens in this embodiment are shown in Table 1.

[0095] Table 1

[0096]

[0097] When the radius of curvature of the surfaces of the diaphragm 2, the filter 4, and the image plane IMA 5 in Table 1 is Infinity, it means that this surface is a plane.

[0098] The aspheric surface in the lens is described by the following formula (1):

[0099] z = (cr 2 ) / {1 + [1 - (k + 1)(c 2 r 2 )]1 / 2} + A4r 4 + A6r 6 + A8r 8 + A10r 10 + A12r 12 + A14r 14 + A16r 16 (1)

[0100] Among them, k is the conic coefficient, A4, A6, A8, A10, A12, A14, A16 are the aspheric surface high-order term coefficients, c is the curvature at the center of the optical surface, c = 1 / r, r is the perpendicular distance from the point on the aspheric curve to the optical axis, and z is the aspheric depth (the perpendicular distance between the point on the aspheric surface with a distance r from the optical axis and the tangent plane at the vertex of the aspheric optical axis). For convenience, the aspheric surfaces of each lens surface use the aspheric surface shown in the above formula (1). However, the present invention is not limited to the aspheric polynomial form represented by this formula (1).

[0101] The parameters of the aspheric lenses of each lens in this embodiment are shown in Table 2.

[0102] Table 2

[0103] Surface number k A4 A6 A8 A10 A12 A14 A16 S1 -3.04E-01 6.07E-03 1.68E-03 -2.03E-04 5.77E-04 -2.37E-04 5.82E-05 0.00E+00 S2 2.22E-01 -2.10E-02 -6.15E-02 -4.57E-02 1.69E-01 -6.64E-02 -2.92E-02 0.00E+00 S4 -1.00E+02 -1.72E-02 2.63E-03 -4.17E-03 1.32E-03 5.57E-04 -1.99E-04 0.00E+00 S5 -1.99E+00 -2.40E-02 -3.15E-03 2.71E-04 1.33E-05 -5.18E-05 3.16E-06 0.00E+00

[0104] The binary diffraction surface coefficients in the lenses of this embodiment can be defined by the following diffraction surface equation, but are not limited to the following representation methods:

[0105] Φ = α 1 ρ 2 + α 2 ρ 4 + α 3 ρ 6 + α 4 ρ 8 + α 5 ρ 10 + α 6 ρ 12 + α 7 ρ 14 (2)

[0107] Among them, Φ is the phase of the diffraction surface; ρ is the normalized semi-aperture perpendicular to the optical axis of the lens; α 1 、α 2 、α 3, α 4 , α 5 , α 6 , α 7 is the diffraction surface phase coefficient.

[0108] The diffraction surface phase coefficient of the lens in this embodiment is shown in Table 3.

[0109] Table 3

[0110]

[0111] The optical parameters of the lens of this embodiment are shown in Table 4.

[0112] Table 4

[0113] Focal length f1 of the first lens -21.34 Focal length f2 of the second lens 4.05 Overall focal length f of the lens 4.46 BFL 2.1 FOV 57.9 <![CDATA[Y m > 4.4 <![CDATA[D 1 > 1.46 <![CDATA[Y 1 > 0.078 TTL 6.75 <![CDATA[FOV / Y m / 2]]> 6.58 TTL / f 1.51 <![CDATA[2*D 1 / f]]> 0.65 <![CDATA[Y 1 *180 / pi]]> 4.47

[0114] In this embodiment, the second lens 3 has the largest optical power, and a plastic material with a refractive index temperature coefficient of dn / dt of -3.35×10 -5 is selected to offset the influence of the linear expansion coefficient of the high-refraction and high-Abbe material, which causes the high-temperature focal plane to move away from the object plane.

[0115] Figure 2 is the field curvature curve of Embodiment 1. The ordinate is the field angle, and the abscissa is the distance of the image point from the paraxial image plane. The field curvature curve shows the distance from the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and is divided into meridional field curvature and sagittal field curvature. Figure 2 The two lines in it are relatively close, indicating that the optical field curvature of the lens is small, the resolution is good, and the image is clear.

[0116] Figure 3 is the distortion curve of Embodiment 1. The ordinate is the field angle, and the abscissa is the percentage of distortion. Distortion belongs to the chief ray aberration and reflects the similarity degree of the object image. From Figure 3 it can be seen that the lens of this embodiment has a small distortion and a low image distortion degree.

[0117] Figure 4 is the MTF VS Field curve graph of Embodiment 1, which reflects the resolution ability of the lens. From Figure 4 it can be seen that for the lens of this embodiment, the curve of 60LP / mm is concentrated and the MTF value is very high, which can reflect that the lens has a high resolution and clear imaging.

[0118] Figure 5 is the relative illumination curve of the lens of Embodiment 1 in the Y field of view, which reflects the uniformity of the picture illumination of the lens. From Figure 5It can be seen that for the lens of this embodiment, under the condition of a maximum field of view angle of 60°, the relative illumination remains stably above 0.8. This technical indicator is significantly better than the conventional design standard of vehicle-mounted lenses (usually requiring RI>0.6). Thanks to this characteristic, the lens has achieved a substantial improvement in the illumination uniformity from the center to the edge. It can still maintain the brightness consistency of the picture edge in an extremely dark environment with an illumination as low as 0.001 lux, effectively eliminating the common edge vignetting phenomenon of traditional vehicle-mounted lenses in backlight or tunnel scenes, ensuring that the imaging picture has no dark corner defects, and providing a reliable optical guarantee for the visual perception module of the intelligent driving system.

[0119] Figure 6 , 7 Figures 6, 7, and 8 are the temperature analysis curves of the lens of Embodiment 1 of this embodiment at temperature environments of -40°C, 20°C, and 85°C respectively. It can be seen that the defocus amounts of the lens of Embodiment 1 at high temperature of 85°C and low temperature of -40°C are both less than 10μm. Such a small defocus amount ensures that the lens can capture high-definition pictures at high temperature of 85°C and low temperature of -40°C.

[0120] Embodiment 2

[0121] As Figure 9-16 shown, a diffractive-refractive hybrid vehicle-mounted lens includes a first lens 1, a diaphragm 2, a second lens 3, a filter 4, and an image plane IMA 5 sequentially arranged along the optical axis direction from the object side to the image side.

[0122] In this embodiment, binary optical technology is introduced. The second lens 3 is designed as a diffractive lens, and the object side surface of the second lens 3 is a binary diffractive surface. Compared with traditional optical technology, diffractive lenses exhibit significant advantages: thinner thickness, lighter weight, and higher design flexibility. These characteristics provide strong support for the miniaturization and integration of optical systems.

[0123] The first lens 1 has a positive optical power. Its object side surface is convex, and its image side surface is concave. The first lens 1 is crescent-shaped, which is beneficial for collecting light, reducing distortion, and improving imaging quality.

[0124] The second lens 3 has a positive optical power. Its object side surface is concave, and its image side surface is convex.

[0125] The diaphragm 2 is arranged between the first lens 1 and the second lens 3, which is beneficial for reducing the assembly sensitivity, reducing aberration, and also beneficial for reducing the lens aperture, enabling the picture to remain clear within the temperature range of -40°C to +85°C.

[0126] The specific parameters of each lens in this embodiment are shown in Table 5.

[0127] Table 5

[0128]

[0129]

[0130] When the radius of curvature of the surfaces of the aperture stop 2, the filter 4, and the image plane IMA 5 in Table 5 is Infinity, it indicates that this surface is a plane.

[0131] The aspherical surface in the lens is described by the following formula (1):

[0132] z = (cr 2 ) / {1 + [1 - (k + 1)(c 2 r 2 )]1 / 2} + A4r 4 + A6r 6 + A8r 8 + A10r 10 + A12r 12 + A14r 14 + A16r 16 (1)

[0133] Where k is the conic coefficient, A4, A6, A8, A10, A12, A14, A16 are the aspherical high-order term coefficients, c is the curvature at the center of the optical surface, c = 1 / r, r is the perpendicular distance from the point on the aspherical curve to the optical axis, and z is the aspherical depth (the perpendicular distance between the point on the aspherical surface at a distance r from the optical axis and the tangent plane at the vertex of the aspherical surface on the optical axis). For convenience, the aspherical surfaces of each lens surface use the aspherical surface shown in the above formula (1). However, the present invention is not limited to the aspherical polynomial form represented by this formula (1).

[0134] The parameters of the aspherical lenses of each lens in this embodiment are shown in Table 6.

[0135] Table 6

[0136] Surface number k A4 A6 A8 A10 A12 A14 A16 S1 -2.80E-01 1.26E-02 2.07E-03 4.45E-03 -9.72E-05 -1.22E-03 6.84E-04 6.90E-05 S2 2.10E+00 -1.96E-02 -1.12E-03 -7.79E-02 9.73E-02 -4.43E-02 -4.49E-02 -9.43E-13 S4 6.12E+00 -1.05E-02 -8.14E-03 5.29E-03 1.07E-02 2.06E-05 2.78E-03 4.80E-15 S5 -1.83E+00 -1.30E-02 -2.22E-03 2.47E-04 3.78E-05 -4.74E-05 5.87E-06 0.00E+00

[0137] In the lens of this embodiment, the binary diffraction surface coefficients can be defined by the following diffraction surface equation, but are not limited to the following representation:

[0138] Φ = α 1 ρ 2 + α 2 ρ 4 + α 3 ρ 6 + α 4 ρ 8 + α 5 ρ 10 + α 6 ρ 12 + α 7 ρ 14 + α 8 ρ16 (3)

[0139] Among them, Φ is the phase of the diffraction surface; ρ is the normalized semi-aperture of the lens perpendicular to the optical axis; α 1 , α 2 , α 3 , α 4 , α 5 , α 6 , α 7 , α 8 are the diffraction surface phase coefficients.

[0140] The diffraction surface phase coefficients of the lens in this embodiment are shown in Table 7.

[0141] Table 7

[0142]

[0143] The optical parameters of the lens of this embodiment are shown in Table 8.

[0144] Table 8

[0145] Focal length f1 of the first lens 12.74 Focal length f2 of the second lens 7.68 Overall focal length f of the lens 4.37 BFL 2.65 FOV 57.8 <![CDATA[Y m > 4.4 <![CDATA[D 1 > 1.33 <![CDATA[Y 1 > 0.076 TTL 6.95 <![CDATA[FOV / Y m / 2]]> 6.57 TTL / f 1.59 <![CDATA[2*D 1 / f]]> 0.61 <![CDATA[Y 1 *180 / pi]]> 4.35

[0146] In this embodiment, the first lens 1 has the largest optical power, and a plastic material with a refractive index temperature coefficient dn / dt of -7.1×10 -5 is selected to offset the influence of the linear expansion coefficient of the high-refractive-index and high-Abbe material on the high-temperature focal plane moving away from the object plane.

[0147] Figure 10 is the field curvature curve of Embodiment 2. The ordinate is the field angle, and the abscissa is the distance of the image point deviating from the paraxial image plane. The field curvature curve shows the distance from the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and is divided into meridional field curvature and sagittal field curvature. Figure 10 The two lines in

[0148] Figure 11 are relatively close, indicating that the optical field curvature of the lens is small, the resolution is good, and the image is clear. Figure 11 As can be seen from

[0149] Figure 12 is the distortion curve of Embodiment 2. The ordinate is the field angle, and the abscissa is the percentage of distortion. Distortion belongs to the principal ray aberration and reflects the similarity degree of the object and image. From Figure 12 it can be seen that the distortion of the lens in this embodiment is small and the image distortion degree is low.

[0150] Figure 13This is the relative illumination curve of the lens in Embodiment 2 under the Y field of view, which reflects the uniformity of the picture illumination of the lens. From Figure 13 It can be seen that for the lens of this embodiment, under the condition of the maximum field of view angle of 60°, the relative illumination still stably maintains above 0.8. This technical index is significantly better than the conventional design standard of vehicle-mounted lenses (usually requiring RI>0.6). Thanks to this characteristic, the lens has achieved a significant improvement in the illumination uniformity from the center to the edge, and can still maintain the brightness consistency of the picture edge in an extremely dark light environment with an illumination as low as 0.001 lux. It can effectively eliminate the common edge vignetting phenomenon of traditional vehicle-mounted lenses in backlight or tunnel scenes, ensuring that the imaging picture has no dark corner defect, and providing a reliable optical guarantee for the visual perception module of the intelligent driving system.

[0151] Figure 14 、 15 、16 are respectively the temperature analysis curves of the lens in Embodiment 2 under the temperature environments of -40°C, 20°C, and 85°C. It can be seen that the defocus amounts of the lens in Embodiment 2 at the high temperature of 85°C and the low temperature of -40°C are both less than 10μm. Such a small defocus amount ensures that the lens can capture high-definition pictures at both the high temperature of 85°C and the low temperature of -40°C.

[0152] The rest is the same as Embodiment 1.

[0153] Embodiment 3

[0154] As Figure 17-24 shown, a diffractive-refractive hybrid vehicle-mounted lens includes a first lens 1, a diaphragm 2, a second lens 3, a filter 4, and an image plane IMA 5 sequentially arranged along the optical axis direction from the object side to the image side.

[0155] In this embodiment, binary optical technology is introduced, and the second lens 3 is designed as a diffractive lens, and the object side surface of the second lens 3 is a binary diffractive surface. Compared with traditional optical technology, diffractive lenses exhibit significant advantages: thinner thickness, lighter weight, and higher design flexibility. These characteristics provide strong support for the miniaturization and integration of optical systems.

[0156] The first lens 1 has a positive optical power. Its object side surface is convex, and its image side surface is concave. The first lens 1 is crescent-shaped, which is beneficial for collecting light, reducing distortion, and improving imaging quality.

[0157] The second lens 3 has a positive optical power. Its object side surface is concave, and its image side surface is convex.

[0158] The diaphragm 2 is arranged between the first lens 1 and the second lens 3, which is beneficial for reducing the assembly sensitivity, reducing aberration, and also beneficial for reducing the lens aperture, so as to keep the picture clear within the temperature range of -40°C to +85°C.

[0159] The specific parameters of each lens in this embodiment are shown in Table 9.

[0160] Table 9

[0161]

[0162] When the radius of curvature of the surfaces of the diaphragm 2, the filter 4, and the image plane IMA 5 in Table 9 is Infinity, it means that this surface is a plane.

[0163] The description of the aspherical surface in the lens is as follows in Equation (1):

[0164] z = (cr 2 ) / {1 + [1 - (k + 1)(c 2 r 2 )]1 / 2} + A4r 4 + A6r 6 + A8r 8 + A10r 10 + A12r 12 + A14r 14 + A16r 16 (1)

[0165] Among them, k is the conic coefficient, A4, A6, A8, A10, A12, A14, A16 are the aspherical high-order term coefficients, c is the curvature at the center of the optical surface, c = 1 / r, r is the perpendicular distance from the point on the aspherical curve to the optical axis, and z is the aspherical depth (the perpendicular distance between the point on the aspherical surface with a distance of r from the optical axis and the tangent plane at the vertex of the aspherical optical axis). For convenience, the aspherical surfaces of each lens surface use the aspherical surface shown in the above Equation (1). However, the present invention is not limited to the aspherical polynomial form represented by this Equation (1).

[0166] The parameters of the aspherical lenses of each lens in this embodiment are shown in Table 10.

[0167] Table 10

[0168] Surface number k A4 A6 A8 A10 A12 A14 A16 S1 -3.01E-01 1.20E-02 1.57E-03 3.62E-03 4.16E-04 -1.11E-03 4.75E-04 7.30E-05 S2 2.13E+00 -2.12E-02 4.41E-03 -8.78E-02 1.02E-01 -4.43E-02 -4.49E-02 -3.67E-12 S4 5.05E+00 -8.63E-03 -6.29E-03 6.48E-03 1.10E-02 5.65E-04 2.78E-03 -4.75E-12 S5 -1.84E+00 -1.31E-02 -2.09E-03 2.63E-04 3.97E-05 -4.65E-05 6.15E-06 0.00E+00

[0169] The binary diffraction surface coefficients in the lenses of this embodiment can be defined by the following diffraction surface equation, but are not limited to the following representation:

[0170] Φ = α 1 ρ 2 + α 2 ρ 4 + α 3 ρ 6 + α 4 ρ 8 + α 5 ρ 10 + α6 ρ 12 +α 7 ρ 14 +α 8 ρ 16 (3)

[0171] where Φ is the phase of the diffraction surface; ρ is the normalized semi-aperture of the lens perpendicular to the optical axis; α 1 、α 2 、α 3 、α 4 、α 5 、α 6 、α 7 、α 8 are the phase coefficients of the diffraction surface.

[0172] The phase coefficients of the diffraction surface of the lens in this embodiment are shown in Table 11.

[0173] Table 11

[0174]

[0175] The optical parameters of the lens in this embodiment are shown in Table 12.

[0176] Table 12

[0177]

[0178]

[0179] In this embodiment, the first lens 1 has the largest optical power, and a plastic material with a refractive index temperature coefficient dn / dt of -3.35×10 -5 is selected to offset the influence of the linear expansion coefficient of the high-refractive-index and high-Abbe material on the high-temperature focal plane moving away from the object plane.

[0180] Figure 18 is the field curvature curve of Embodiment 3. The ordinate is the field angle, and the abscissa is the distance of the image point from the paraxial image plane. The field curvature curve shows the distance from the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and is divided into meridional field curvature and sagittal field curvature. Figure 18 The two lines in it are relatively close, indicating that the optical field curvature of the lens is small, the resolution is good, and the image is clear.

[0181] Figure 19 is the distortion curve of Embodiment 3. The ordinate is the field angle, and the abscissa is the percentage of distortion. Distortion belongs to the chief ray aberration and reflects the similarity degree of the object and image. As can be seen from Figure 19 , the distortion of the lens in this embodiment is small, and the image distortion degree is low.

[0182] Figure 20This is the MTF VS Field curve graph of Embodiment 3, which reflects the resolution ability of the lens. From Figure 20 it can be seen that for the lens of this embodiment, the curve of 60LP / mm is concentrated and the MTF value is very high, which can reflect that the lens has high resolution and clear imaging.

[0183] Figure 21 This is the relative illumination curve of the lens of Embodiment 3 under the Y field of view, which reflects the evenness of the picture illumination of the lens. From Figure 21 it can be seen that for the lens of this embodiment, under the condition of the maximum field of view angle of 60°, the relative illumination still stably maintains above 0.8. This technical index is significantly better than the conventional design standard of vehicle-mounted lenses (usually requiring RI>0.6). Thanks to this characteristic, the lens has achieved a significant improvement in the illumination uniformity from the center to the edge, and can still maintain the brightness consistency of the picture edge in an extremely dark environment with an illumination as low as 0.001 lux, effectively eliminating the common edge vignetting phenomenon of traditional vehicle-mounted lenses in backlight or tunnel scenes, ensuring that the imaging picture has no dark corner defect, and providing a reliable optical guarantee for the visual perception module of the intelligent driving system.

[0184] Figure 22 , 23 and 24 are the temperature analysis curves of the lens of Embodiment 3 under the temperature environments of -40°C, 20°C, and 85°C respectively. It can be seen that the defocus amounts of the lens of Embodiment 3 at the high temperature of 85°C and the low temperature of -40°C are both less than 10μm. Such a small defocus amount ensures that the lens can capture high-definition pictures at the high temperature of 85°C and the low temperature of -40°C.

[0185] The rest is the same as Embodiment 1.

[0186] For the parts or structures not specifically described in the present invention, existing technologies or existing products can be adopted, and no further elaboration will be made here.

[0187] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, are similarly included in the patent protection scope of the present invention.

Claims

1. A refractive-diffractive hybrid vehicle lens, characterized in that: The invention comprises a first lens and a second lens which are arranged in sequence along the optical axis from the object side toward the image side. The first lens or the second lens is a diffractive lens. The first lens has positive or negative optical power, and its object side surface is convex and its image side surface is concave. The second lens has positive optical power and its image side surface is convex.

2. The refractive-diffractive hybrid vehicle lens according to claim 1, characterized in that: The image-side surface of the first lens is a binary diffraction surface.

3. The refractive-diffractive hybrid vehicle lens according to claim 1, characterized in that: The object side surface of the second lens is a binary diffraction surface.

4. The refractive-diffractive hybrid vehicle-mounted lens according to claim 1, characterized in that: The object side surface of the second lens is a concave surface or a convex surface.

5. The refractive-diffractive hybrid vehicle lens according to claim 1, characterized in that: The first lens meets the following conditions: 0.61≤2*D1 / f≤0.66; Wherein, 2*D1 is the effective diameter of the first lens, and f is the focal length of the entire lens group.

6. The refractive-diffractive hybrid vehicle-mounted lens according to claim 1, characterized in that: The refractive index Nd1 of the first lens satisfies 1.54≤Nd1≤1.66, and the Abbe constant Vd1 of its material satisfies 20.4≤Vd1≤56; the refractive index Nd2 of the second lens satisfies 1.54≤Nd2≤1.66, and the Abbe constant Vd2 of its material satisfies 20.4≤Vd2≤56.

7. The refractive-diffractive hybrid vehicle-mounted lens according to claim 1, characterized in that: The refractive-diffractive hybrid vehicle-mounted lens meets the following conditions: -4.8≤f1 / f≤3.32; 0.90≤f2 / f≤1.83; Among them, f1 and f2 are the focal lengths of the first lens and the second lens respectively, and f is the focal length value of the entire lens group.

8. The refractive-diffractive hybrid vehicle-mounted lens according to claim 1, characterized in that: The refractive-diffractive hybrid vehicle-mounted lens meets the following conditions: 6.57≤FOV / Ym / 2≤6.85; Among them, FOV is the horizontal or maximum lens field of view, and Ym is the image height corresponding to the field of view angle FOV.

9. The refractive-diffractive hybrid vehicle lens according to claim 1, characterized in that: The refractive-diffractive hybrid vehicle-mounted lens meets the following conditions: 1.51≤TTL / f≤1.65; Wherein, TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the lens on the optical axis, and f is the focal length value of the entire lens.

10. The refractive-diffractive hybrid vehicle lens according to claim 1, characterized in that: The refractive-diffractive hybrid vehicle-mounted lens meets the following conditions: 4.24≤Y1*180 / pi; Among them, Y1 is the lens image height corresponding to the half field angle of 1°, and pi is the pi.

11. The refractive-diffractive hybrid vehicle-mounted lens according to claim 1, characterized in that: The refractive-diffractive hybrid vehicle-mounted lens meets the following conditions: BFL / TTL>0.31; Wherein, BFL is the distance from the center of the image side surface of the second lens to the imaging surface of the lens on the optical axis, and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the lens on the optical axis.

12. A camera device, characterized in that: The invention comprises an electronic photosensitive element and a refractive-diffractive hybrid vehicle-mounted lens as claimed in any one of claims 1 to 11.

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