WO2023216219A1 - Infrared projection lens - Google Patents

Abstract

An infrared projection lens with an excellent projection performance is provided. The lens is comprised of a diaphragm, a first lens, a second lens, and a third lens, which are sequentially arranged from an imaging side to a light source side. The first lens is a lens having a positive focal power, and has a concave surface on a paraxial imaging side and a convex surface on a paraxial light source side, and at least one of the two surfaces of the first lens is aspheric. The second lens is a lens having a negative focal power, and has a concave surface on the paraxial imaging side and a convex surface on the paraxial light source side, and at least one of the two surfaces of the second lens is aspheric. The third lens is a lens having a positive focal power, and has a convex surface on the paraxial imaging side, and at least one of two surfaces of the third lens is aspheric. The lens satisfies 0.1<|Y/(f*TTL)|<0.4, where f is a focal length of the lens, Y is a maximum object height of the lens, and TTL is a distance between a diaphragm surface and an imaging surface of the lens.

Description

Infrared projection lens Technical field

Embodiments of the present application relate to the field of optics, and more specifically, to infrared projection lenses.

Background technique

With the rise of face recognition, somatosensory games, pattern recognition and other fields, 3D depth detection has become a hot topic. In three-dimensional depth detection, the 940nm light source is usually used as the signal light source. First, it is to avoid the interference of the visible light band in sunlight on the signal. Second, the water molecules in the air absorb less 940nm light. As a signal transmitting device in depth detection, the infrared projection lens is crucial to the accuracy and field of view range in depth detection. Therefore, how to improve the performance of infrared projection lenses has become an urgent problem to be solved.

Contents of the invention

Embodiments of the present application provide an infrared projection lens with excellent projection performance.

In a first aspect, an infrared projection lens is provided. The lens is composed of an aperture, a first lens, a second lens and a third lens arranged in sequence from the imaging side to the light source side, wherein: the first lens is positive light. The first lens has a concave surface on the paraxial imaging side, the first lens has a convex surface on the paraxial light source side, and at least one of the two surfaces of the first lens is aspherical. ; The second lens is a lens with negative optical power, the second lens is concave on the imaging side of the paraxial axis, and is convex on the light source side of the paraxial axis, and at least one of the two surfaces of the second lens is The surface is an aspheric surface; the third lens is a lens with positive optical power, the third lens is a convex surface on the paraxial imaging side, and at least one of the two surfaces of the third lens is an aspheric surface; wherein, The lens satisfies 0.1<|Y/(f*TTL)|<0.4, where f is the focal length of the lens, Y is the maximum object height of the lens, and TTL is the diaphragm surface to the imaging surface of the lens. the distance between.

In one implementation, the lens also satisfies 0.3<f/TTL<0.5.

In one implementation, the lens also satisfies 0.2<Y/TTL<0.4.

In one implementation, the field of view angle FOV of the lens satisfies 60°<FOV<85°, and/or the F-number of the lens satisfies F-number<2.4.

In one implementation, the lens meets at least one of the following conditions: |Y/(f*TTL)|=0.299, f/TTL=0.416, Y/TTL=0.347, and the F number of the lens= 2.27, the FOV of the lens=80°.

In one implementation, the lens meets at least one of the following conditions: |Y/(f*TTL)|=0.218, f/TTL=0.410, Y/TTL=0.295, and the F number of the lens= 1.78, FOV of the lens=72°.

In one implementation, the lens meets at least one of the following conditions: |Y/(f*TTL)|=0.182, f/TTL=0.410, Y/TTL=0.269, and the F number of the lens= 1.9, the FOV of the lens=66°.

In one implementation, the lens meets at least one of the following conditions: |Y/(f*TTL)|=0.214, f/TTL=0.450, Y/TTL=0.305, and the F number of the lens= 1.8, FOV of the lens=68°.

In one implementation, the focal length f ₁ of the first lens and the focal length f ₂ of the second lens satisfy -1.3<f ₂ /f ₁ <-0.5; and/or, the third lens The focal length f ₃ and the focal length f ₁ of the first lens satisfy 0.3<f ₃ /f ₁ <1.

In one implementation, the lens satisfies at least one of the following conditions: the focal length f ₁ of the first lens and the focal length f of the lens satisfy 0.8<f ₁ /f<1.3; The focal length f ₂ of the second lens and the focal length f of the lens satisfy -1.3<f ₂ /f<-0.5; the focal length f ₃ of the third lens and the focal length f of the lens satisfy 0.4<f ₃ /f<1.1.

In one implementation, the center thickness CT1 of the first lens and the center thickness CT2 of the second lens satisfy 0.5<CT1/CT2<1.5; and/or the center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy 0.2<CT2/CT3<1.

In one implementation, the focal length f ₁ of the first lens and the radius of curvature R1 of the imaging side of the first lens satisfy -1<f ₁ /R1<-0.2; and/or, the first lens The relationship between the focal length f ₁ of a lens and the radius of curvature R2 on the light source side of the first lens satisfies -2.5<f ₁ /R2<-1.5.

In one implementation, the focal length f ₂ of the second lens and the radius of curvature R3 of the imaging side of the second lens satisfy: 2<f ₂ /R3<4.5; the focal length f of the second lens ₂ and the curvature radius R4 on the light source side of the second lens satisfy 0.4<f ₂ /R4<2.

In one implementation, the focal length f ₃ of the third lens and the radius of curvature R5 of the imaging side of the third lens satisfy 1.4<f ₃ /R5<1.6; the focal length f ₃ of the third lens and the radius of curvature R6 on the light source side of the third lens satisfies -0.2<f ₃ /R6<0.1.

In one implementation, the lens satisfies at least one of the following conditions: the radius of curvature R1 on the imaging side of the first lens and the radius of curvature R2 on the light source side of the first lens satisfy 2<R1 /R2<4.5; the radius of curvature R3 of the imaging side of the second lens and the radius of curvature R4 of the light source side of the second lens satisfy 0.2<R3/R4<0.45; the radius of curvature of the imaging side of the third lens The radius of curvature R5 and the radius of curvature R6 on the light source side of the third lens satisfy -0.2<R5/R6<0.1.

In one implementation, the refractive index of the material of the first lens is n ₁ >1.6, the refractive index of the material of the second lens is n ₂ >1.6, and the refractive index of the material of the third lens is n ₃ >1.6; and/or, the dispersion coefficient v ₁ of the material of the first lens > 22.0, the dispersion coefficient v ₂ of the material of the second lens > 22.0, the dispersion coefficient v ₃ of the material of the third lens > 22.0 .

In one implementation, the infrared projection lens is used for depth detection.

In the embodiment of the present application, the infrared projection lens is a three-piece lens. The lens includes a first lens, a second lens and a third lens arranged in sequence from the imaging side to the light source side, which can project the lattice of the light source to a longer distance. on the target and generates reflected light carrying depth information of the target. By designing the power and shape of the three lenses and making the f, Y and TTL of the lens meet the appropriate conditions, that is, 0.1<|Y/(f*TTL)|<0.4, the lens has a large The FOV and small F number can meet the needs of a larger detection field of view and maintain good projection performance.

Description of the drawings

Figure 1 is a schematic structural diagram of an infrared projection lens module according to an embodiment of the present application.

Figure 2 is a schematic diagram of the imaging optical path in the infrared projection lens module shown in Figure 1.

FIG. 3 is a possible structural diagram of the infrared projection lens shown in FIG. 2 .

FIG. 4 is a schematic diagram of aberration of the lens shown in FIG. 3 .

FIG. 5 is a schematic diagram of the MTF curve of the lens shown in FIG. 3 .

FIG. 6 is a schematic diagram of an RI curve of the lens shown in FIG. 3 .

FIG. 7 is a possible structural diagram of the infrared projection lens shown in FIG. 2 .

FIG. 8 is a schematic diagram of aberration of the lens shown in FIG. 7 .

FIG. 9 is a schematic diagram of the MTF curve of the lens shown in FIG. 7 .

FIG. 10 is a schematic diagram of the RI curve of the lens shown in FIG. 7 .

FIG. 11 is a possible structural diagram of the infrared projection lens shown in FIG. 2 .

FIG. 12 is a schematic diagram of aberration of the lens shown in FIG. 11 .

FIG. 13 is a schematic diagram of the MTF curve of the lens shown in FIG. 11 .

FIG. 14 is a schematic diagram of an RI curve of the lens shown in FIG. 11 .

FIG. 15 is a possible structural diagram of the infrared projection lens shown in FIG. 2 .

FIG. 16 is a schematic diagram of aberration of the lens shown in FIG. 15 .

FIG. 17 is a schematic diagram of the MTF curve of the lens shown in FIG. 15 .

FIG. 18 is a schematic diagram of an RI curve of the lens shown in FIG. 15 .

Detailed ways

The technical solutions in this application will be described below with reference to the accompanying drawings.

Figure 1 is a schematic structural diagram of an infrared projection lens according to an embodiment of the present application. As shown in FIG. 1 , the infrared projection lens 100 includes a projection lens (hereinafter also referred to as lens) 110 and an infrared light source 130 .

Among them, the projection lens 110 is an optical imaging element, which can be an optical structure composed of a spherical surface and/or an aspheric surface, and is used to project the lattice of the light source onto the target. The projection lens 110 can be composed of one lens or multiple lenses. Lenses can usually be injection molded from materials such as resin. The infrared light source 130 is an infrared light source lattice with certain arrangement rules, such as a vertical cavity surface emitting laser (VCSEL) array light source that is usually rectangular or has a certain special arrangement rule. The wavelength of this light source is usually 940nm. The projection lens 110 projects the VCSEL light source lattice onto the detection target, and carries the depth information of the target through reflection on the target surface.

The infrared projection lens 100 may also include other structures and devices. For example, as shown in Figure 1, the infrared projection lens 100 also includes a holder (Holder) 120. The holder 120 is used to connect the projection lens 110 and the infrared light source 130 together. The accuracy of controlling the defocus and eccentricity of the projection lens 110 is controlled.

It should be understood that the structure of the infrared projection lens 100 shown in FIG. 1 is only an example. The embodiment of the present application mainly designs the projection lens 110 part, and does not impose any restrictions on the positions and parameters of other structures and devices.

The infrared projection lens provided by the embodiment of the present application has a larger field of view and a smaller F number, which can meet the needs of a larger detection field of view and ensure its ability to project light.

To facilitate better understanding, firstly, the parameter indicators involved in the embodiments of the present application that can be used to evaluate the performance of the infrared projection lens are briefly introduced.

Field of View (FOV): Used to characterize the field of view of the lens. When the lens sizes are equal, the larger the FOV of the lens, the larger the range of the lens's projection field of view.

Working F-number, or F-number (Fno): The reciprocal of the relative aperture of the lens, used to characterize the amount of light projected by the lens. The smaller the F number, the more light the lens projects.

Distortion: used to measure the degree of visual distortion of an image. The smaller the distortion, the better the imaging effect.

Relative Illumination (RI): refers to the ratio of the illumination of different coordinate points on the imaging surface to the illumination of the center point. The smaller the relative illumination, the more uneven the illumination of the imaging surface, which can easily lead to underexposure or overexposure of the center in some positions. Exposure issues affect imaging quality; the greater the relative illumination, the higher the imaging quality.

In the embodiment of the present application, the infrared projection lens 100 can be used in depth detection, for example, to use infrared light to achieve depth detection of a target.

Figure 2 is a schematic diagram of an infrared projection lens according to an embodiment of the present application. The lens 110 includes a first lens 111, a second lens 112 and a third lens 113 arranged in sequence from the imaging side to the light source side. The imaging side is the projection target side.

The first lens 111 is a lens with positive optical power. The first lens 111 is a concave surface on the imaging side of the paraxial axis. The first lens 111 is a convex surface on the light source side of the paraxial axis. At least one of the two surfaces of the first lens 111 is is aspherical.

The second lens 112 is a lens with negative refractive power. The second lens 112 has a concave surface on the imaging side of the paraxial axis and a convex surface on the light source side of the paraxial axis. At least one of the two surfaces of the second lens 112 is an aspherical surface. .

The third lens 113 is a lens with positive optical power. The third lens 113 is a convex surface on the paraxial imaging side. At least one of the two surfaces of the third lens 113 is an aspherical surface.

The first lens 111 , the second lens 112 and the third lens 113 may be injection molded using resin material or other plastic materials, for example.

In some implementations, the lens 110 further includes an aperture 114 disposed on a side of the first lens 111 close to the imaging side.

The embodiment of the present application designs the parameters of each of the above lenses in the lens 100, such as the focal length f of the lens 110, the maximum object height Y of the lens 110, and the total longitudinal length (Total Trace Length, TTL) of the lens 110, that is, the lens Parameters such as the distance between the aperture surface of 110 and the imaging surface enable the lens 110 to have a larger field of view FOV and a smaller F number. For example, the focal length f of the lens 110, the maximum object height Y of the lens 110, and TTL can satisfy the preset condition 0.1<|Y/(f*TTL)|<0.4.

The lens 110 in the embodiment of the present application is a three-piece lens. The lens 110 includes a first lens 111, a second lens 112 and a third lens 113 arranged in sequence from the imaging side to the light source side. It can project the dot matrix of the light source 110 to a relatively large area. on a distant target and generates reflected light that carries depth information about the target. By designing the power and shape of the three lenses and making the f, Y and TTL of the lens 110 meet appropriate conditions such as 0.1<|Y/(f*TTL)|<0.4, the lens 110 With a large field of view FOV and a small F number, it can meet the needs of a larger detection field of view and maintain good projection performance.

The f, Y and TTL of the lens 110 affect the FOV and F number of the lens, and f, Y and TTL also restrict and influence each other. Therefore, by controlling f, Y and TTL, the above-mentioned relationship is satisfied, for example, 0.1< |Y/(f*TTL)|<0.4, can make the lens 110 have a larger FOV, allow the lens to obtain a larger wide-angle field of view, detect a larger range, and can make the lens 110 have a smaller F number. Gather more light to improve Lens 111 performance.

For example, when the relationship between f, Y and TTL of the lens 110 is 0.1<|Y/(f*TTL)|<0.4, the FOV of the lens 110 satisfies 60°<FOV<85°. Further, it can also be used The FOV of the lens 110 meets the requirements of 65°＜FOV＜85°, 65°＜FOV≤80°, 65°＜FOV≤75° or 65°＜FOV≤70°, etc., to meet the accuracy requirements and field of view requirements of depth detection. Balance; when the relationship between f, Y and TTL of the lens 110 is 0.1<|Y/(f*TTL)|<0.4, the F number of the lens 110 satisfies the F number <2.4. Furthermore, the lens 110 can also be made The F number satisfies F number <2.3 or F number <2.0, so that the lens 110 can collect more light.

It should be understood that the above preset conditions are conditions that the f, Y and TTL of the lens 110 should meet when designing the lens 110, thereby improving the projection performance of the lens 110 while ensuring the required FOV and F number. In some cases, in order to obtain better projection performance, the above preset conditions can also be adjusted appropriately. For example, the preset conditions are 0.1<|Y/(f*TTL)|<0.30, 0.2<|Y/ (f*TTL)|<0.30, 0.1<|Y/(f*TTL)|<0.25, 0.15<|Y/(f*TTL)|<0.30 or 0.15<|Y/(f*TTL)|<0.25 wait.

Furthermore, in other implementations, the relationship between f, Y and TTL of the lens 110 can also satisfy 0.3<f/TTL<0.5 and/or 0.2<Y/TTL<0.4. By further limiting the relationship between f, Y and TTL of the lens 110, the FOV of the lens 110 can be made as large as possible within the above range, and the F number of the lens 110 can be made as small as possible within the above range. This condition can also be adjusted appropriately, for example, 0.3<f/TTL<0.46, 0.4<f/TTL<0.46, 0.2<Y/TTL<0.35, 0.25<Y/TTL<0.35 or 0.2<Y/TTL<0.3 wait.

The above describes the conditions satisfied by each parameter of the lens 110 as a whole. The following describes the parameter design of the first lens 111 , the second lens 112 and the third lens 113 in the lens 110 respectively. When some or all of the following conditions are met among the parameters of each lens, the FOV and F number of the lens 110 can be respectively 60°<FOV<85° and F number<2.4.

The first lens 111 is a lens with positive optical power. The distribution of the positive optical power of the first lens 111 can expand the angle at which the light emerges, so that the lens 110 has a larger FOV. Optionally, the first lens 111 may also satisfy at least one of the following conditions: the focal length f ₁ of the first lens 111 and the radius of curvature R1 of the imaging side of the first lens 111 satisfy -1<f ₁ /R1<-0.2; the focal length f ₁ of the first lens and the radius of curvature R2 of the light source side of the first lens satisfy -2.5<f ₁ /R2<-1.5; the radius of curvature R1 of the imaging side of the first lens 111 and the radius of curvature R1 of the first lens 111 The curvature radius R2 of the light source side of 111 satisfies 2<R1/R2<4.5. Reasonable distribution of the curvature radii of the two surfaces of the first lens 111 helps the lens 110 correct the aberration of the lens 110 when deflecting light.

The second lens 112 is a lens with negative power. The distribution of the negative power of the second lens 112 can effectively correct the aberration of the lens 110 and improve the projection quality of the lens 110 . Optionally, the second lens 112 may also satisfy at least one of the following conditions: the focal length f ₂ of the second lens 112 and the radius of curvature R3 of the imaging side of the second lens 112 satisfy: 2<f ₂ /R3<4.5; the focal length f ₂ of the second lens 112 and the radius of curvature R4 of the light source side of the second lens satisfy 0.4<f ₂ /R4<2; the radius of curvature R3 of the imaging side of the second lens 112 and the radius of curvature R3 of the second lens 112 The radius of curvature R4 on the light source side satisfies 0.2<R3/R4<0.45. Reasonable distribution of the curvature radii of the two surfaces of the second lens 112 helps the second lens 112 better correct the aberration of the lens 110 while contributing negative power.

The third lens 113 is a lens with positive optical power. Optionally, the third lens 113 can also meet at least one of the following conditions: the focal length f ₃ of the third lens and the radius of curvature R5 of the imaging side of the third lens 113 The distance between the focal length f ₃ of the third lens 113 and the radius of curvature R6 of the light source side of the third lens 113 satisfies -0.2<f ₃ /R6<0.1; the imaging side of the third lens 113 satisfies 1.4<f ₃ /R5<1.6. The relationship between the radius of curvature R5 and the radius of curvature R6 of the light source side of the third lens satisfies -0.2<R5/R6<0.1. The third lens 113 is the lens closest to the light source. After the light is emitted from the light source, it first passes through the third lens 113 with positive refractive power to deflect the light to reduce the effective aperture of the first lens 111 and the second lens 112 size, while ensuring that the lens 110 has a larger FOV.

In addition, since 2<R1/R2<4.5, 0.2<R3/R4<0.45, and -0.2<R5/R6<0.1, by designing the respective curvature radii of the three lenses in the lens 110, the FOV and While the F number meets the demand, it can also reduce the sensitivity of the lens 110 and improve the product yield.

In some implementations, the distribution of optical power between each lens in the lens 110 satisfies at least one of the following conditions: the focal length f ₁ of the first lens 111 and the focal length f of the lens 110 satisfy 0.8<f ₁ /f<1.3; the focal length f ₂ of the second lens 112 and the focal length f of the lens 110 satisfy -1.3<f ₂ /f<-0.5; the focal length f ₃ of the third lens 113 and the focal length f of the lens 110 satisfy 0.4<f ₃ /f<1.1; the focal length f ₁ of the first lens 111 and the focal length f ₂ of the second lens 112 satisfy -1.3<f ₂ /f ₁ <-0.5; the focal length f ₃ of the third lens 113 and The focal length f ₁ of the first lens 111 satisfies 0.3<f ₃ /f ₁ <1. By designing the respective focal lengths of the three lenses and reasonably allocating the focal lengths of the first lens 111, the second lens 112 and the third lens 113, the lens 110 can have a larger FOV range and a smaller F number, and at the same time The aberration of the lens 110 is better corrected, and the projection quality of the lens 110 is effectively improved.

In order to make the structure of the lens 110 stronger and extend the service life of the lens 110, the center thickness of the first lens 111, the second lens 112 and the third lens 113, that is, the thickness of the lenses along the optical axis direction, can also be designed. For example, the center thickness CT1 of the first lens 111 and the center thickness CT2 of the second lens 112 satisfy 0.5<CT1/CT2<1.5; for another example, the center thickness CT2 of the second lens 112 and the center thickness CT3 of the third lens 113 It satisfies 0.2<CT2/CT3<1.

In addition, in order to meet dispersion requirements, reduce production costs, and provide a suitable phase difference balance, the refractive index and dispersion coefficient of the materials of the first lens 111 , the second lens 112 , and the third lens 113 can also be designed. For example, the refractive index n ₁ of the material of the first lens 111 is >1.6, and the dispersion coefficient v ₁ of the material of the first lens 111 is >22.0; for another example, the refractive index n2 of the material of the second lens 112 is >1.6, and the refractive index of the material of the second lens 112 is n2 >1.6. The material of the third lens 113 has a dispersion coefficient v2>22.0; for another example, the material of the third lens 113 has a refractive index n3>1.6, and the material of the third lens 113 has a dispersion coefficient v3>22.0.

In the embodiment of the present application, physical parameters such as the curvature radius, thickness, material, and cone coefficient of the first lens 111, the second lens 112, and the third lens 113 in the lens 110 can be controlled, and/or non-linear parameters in the lens 110 can be controlled. The even-order terms in the aspherical higher-order coefficients of the spherical lens enable the parameters of the lens 110 to meet the above conditions, thereby making the FOV of the lens 110 satisfy 60°<FOV<85° and the F number<2.4. Below, some possible specific implementations of the lens 110 in the embodiment of the present application are described in detail, taking Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 as examples.

Example 1

The lens 110 includes three lenses. As shown in FIG. 3 , the lens 110 includes, in order from the imaging side to the light source side: an aperture 114, a first lens 111, a second lens 112 and a third lens 113, and a light source surface 115. The first lens 111 is a lens with positive optical power, the second lens 112 is a lens with negative optical power, and the third lens 113 is a lens with positive optical power.

In order to facilitate distinction and description, in order from the imaging side to the light source side, the imaging surface is marked as S0, the aperture 114 is marked as S1, the two surfaces of the first lens 111 are marked as S2 and S3 respectively, and the second lens 112 The two surfaces of the third lens 113 are marked as S4 and S5 respectively, the two surfaces of the third lens 113 are marked as S6 and S7 respectively, and the light source surface 115 is marked as S8. At least one surface of the lens 110 is an aspherical surface.

Further, by setting the focal length, curvature radius, center thickness, material, cone coefficient and other parameters of each lens in the lens 110, as well as the aspheric higher-order coefficient of the aspheric lens in the lens 110, so that the FOV, F Number, relative illumination, aberration, etc. meet the requirements.

In Embodiment 1, the parameters such as focal length, radius of curvature, and center thickness of each lens are set as shown in Table 1. The settings of the curvature radius, thickness, material (n, v) and conic coefficient of each surface in S0 to S8 are shown in Table 2. The settings of the aspherical higher-order term coefficients A4, A6, A8, A10, A12, A14, and A16 of the aspherical surfaces in S2 to S7 are shown in Table 3. In Table 2, the curvature radii of planes such as S0, S1, and S8 are infinite.

Table 1

project	Parameter value
f 1 /f	1.088
f 2 /f	-1.219
f 3 /f	0.941
f 2 /f 1	-1.120
f 3 /f 1	0.865
f 1 /R1	-0.682
f 1 /R2	-2.076
f 2 /R3	3.819
f 2 /R4	1.482
f 3 /R5	1.511
f 3 /R6	-0.166
CT1/CT2	1.059
CT2/CT3	0.630
R1/R2	3.046
R3/R4	0.388
R5/R6	-0.110
Y/f	0.836
Y/TTL	0.347
Y/(f*TTL)	0.299
f/TTL	0.416

Table 2

table 3

surface	S2	S3	S4	S5	S6	S7
A4	-1.21E+00	3.05E-02	-2.81E+00	-2.16E+00	-1.07E+00	3.69E-01
A6	1.10E+00	2.01E+00	1.25E+01	4.82E+00	1.88E+00	-1.81E+00
A8	-1.37E+01	-7.03E+00	-3.18E+01	-6.67E+00	-1.80E+00	4.48E+00
A10	8.25E+01	1.16E+01	4.98E+01	5.93E+00	6.06E-01	-5.71E+00
A12	-3.66E+03	-6.55E+01	-4.39E+01	-3.91E+00	4.86E-01	3.91E+00
A14	-1.83E+04	1.20E+02	2.51E+01	1.86E+00	-6.03E-01	-1.42E+00
A16	5.21E+05	1.01E+03	9.14E-01	1.02E-01	1.87E-01	2.13E-01

Based on the parameters shown in Table 1, Table 2 and Table 3, the overall focal length of the three-piece infrared wide-angle lens 110 in Embodiment 1 is f=1.161mm, the F number of the lens 110=2.27, and the maximum field of view of the lens 110 is FOV =80°, TTL=2.792mm. It can be seen that the lens 110 in Embodiment 1 has a larger FOV, a smaller working F number, and a smaller lens size (TTL).

Figure 4 shows the aberration curve of the lens 110; Figure 5 shows the modulation transfer function (MTF) curve of the lens 110, that is, the optical transfer function (Optical Transfer Function, OTF) module value; Figure 6 shows The relative illumination of lens 110 is shown. It can be seen from Figures 4 to 6 that when the parameters TTL, f, and Y of the lens 110 meet the above conditions, while the FOV and F number of the lens 110 meet the requirements, the lens 110 also has smaller optical distortion such as distortion. The absolute value of is less than 3%, and the lens 110 has a higher MTF, has higher projection quality, and maintains a higher relative illumination while maintaining a larger FOV.

Example 2

The lens 110 includes three lenses. As shown in FIG. 7 , the lens 110 includes, in order from the imaging side to the light source side: an aperture 114, a first lens 111, a second lens 112 and a third lens 113, and a light source surface 115. The first lens 111 is a lens with positive optical power, the second lens 112 is a lens with negative optical power, and the third lens 113 is a lens with positive optical power.

In order to facilitate distinction and description, in order from the imaging side to the light source side, the imaging surface is marked as S0, the aperture 114 is marked as S1, the two surfaces of the first lens 111 are marked as S2 and S3 respectively, and the second lens 112 The two surfaces of the third lens 113 are marked as S4 and S5 respectively, the two surfaces of the third lens 113 are marked as S6 and S7 respectively, and the light source surface 115 is marked as S8. At least one surface of the lens 110 is an aspherical surface.

Further, by setting the focal length, curvature radius, center thickness, material, cone coefficient and other parameters of each lens in the lens 110, as well as the aspheric higher-order coefficient of the aspheric lens in the lens 110, so that the FOV, F Number, relative illumination, aberration, etc. meet the requirements.

In Embodiment 2, the parameters such as focal length, radius of curvature, and center thickness of each lens are set as shown in Table 4. The settings of the curvature radius, thickness, material (n, v) and conic coefficient of each surface in S0 to S8 are shown in Table 2. The settings of the aspherical higher-order term coefficients A4, A6, A8, A10, A12, A14, and A16 of the aspherical surfaces in S2 to S7 are shown in Table 3. In Table 5, the curvature radii of planes such as S0, S1, and S8 are infinite.

Table 4

table 5

Table 6

surface

S2

S3

S4

S5

S6

S7

A4	-5.01E-01	-2.03E-01	-2.81E+00	-2.09E+00	-1.07E+00	3.36E-01
A6	7.33E-01	7.46E-01	1.26E+01	4.85E+00	1.89E+00	-1.83E+00
A8	-2.14E+01	-6.70E+00	-3.17E+01	-6.65E+00	-1.80E+00	4.48E+00
A10	1.87E+02	2.32E+01	4.97E+01	5.97E+00	6.00E-01	-5.70E+00
A12	-6.92E+02	-4.56E+01	-4.51E+01	-3.83E+00	4.77E-01	3.92E+00
A14	1.22E+03	3.94E+01	2.16E+01	1.96E+00	-6.07E-01	-1.42E+00
A16	2.75E+01	-1.21E+01	-3.68E+00	-3.70E-01	1.91E-01	2.13E-01

Based on the parameters shown in Table 4, Table 5 and Table 6, the overall focal length of the three-piece infrared wide-angle lens 110 in Embodiment 2 is f=1.35mm, the F number of the lens 110=1.78, and the maximum field of view angle of the lens 110 is FOV =72°, TTL=3.29mm. It can be seen that the lens 110 in Embodiment 2 has a larger FOV, a smaller working F number, and a smaller lens size (TTL).

FIG. 8 shows the aberration curve of the lens 110; FIG. 9 shows the MTF curve, that is, the OTF module value of the lens 110; FIG. 10 shows the relative illumination of the lens 110. It can be seen from Figures 8 to 10 that when the parameters TTL, f, and Y of the lens 110 meet the above conditions, while the FOV and F number of the lens 110 meet the requirements, the lens 110 also has smaller optical distortion such as distortion. The absolute value of is less than 2%, and the lens 110 has a higher MTF, has higher projection quality, and maintains a higher relative illumination while maintaining a larger FOV.

Example 3

The lens 110 includes three lenses. As shown in FIG. 11 , the lens 110 includes, in order from the imaging side to the light source side: an aperture 114, a first lens 111, a second lens 112 and a third lens 113, and a light source surface 115. The first lens 111 is a lens with positive optical power, the second lens 112 is a lens with negative optical power, and the third lens 113 is a lens with positive optical power.

In order to facilitate distinction and description, in order from the imaging side to the light source side, the imaging surface is marked as S0, the aperture 114 is marked as S1, the two surfaces of the first lens 111 are marked as S2 and S3 respectively, and the second lens 112 The two surfaces of the third lens 113 are marked as S4 and S5 respectively, the two surfaces of the third lens 113 are marked as S6 and S7 respectively, and the light source surface 115 is marked as S8. At least one surface of the lens 110 is an aspherical surface.

Further, by setting parameters such as the focal length, radius of curvature, center thickness, material, and cone coefficient of each lens in the lens 110, as well as the aspheric higher-order coefficients of the aspheric lenses in the lens 110, the FOV, F Number, relative illumination, aberration, etc. meet the requirements.

In Embodiment 3, the parameters such as focal length, curvature radius, and center thickness of each lens are set as shown in Table 7. The settings of the curvature radius, thickness, material (n, v) and conic coefficient of each surface in S0 to S8 are shown in Table 2. The settings of the aspherical higher-order term coefficients A4, A6, A8, A10, A12, A14, and A16 of the aspherical surfaces in S2 to S7 are shown in Table 9. In Table 8, the curvature radii of planes such as S0, S1, and S8 are infinite.

Table 7

project	Parameter value
f 1 /f	1.102
f 2 /f	-0.887
f 3 /f	0.780
f 2 /f 1	-0.805
f 3 /f 1	0.708
f 1 /R1	-0.555
f 1 /R2	-2.012
f 2 /R3	2.927
f 2 /R4	0.915
f 3 /R5	1.521
f 3 /R6	-0.165
CT1/CT2	1.144
CT2/CT3	0.566
R1/R2	3.621
R3/R4	0.313
R5/R6	-0.108
Y/f	0.657
Y/TTL	0.269
Y(/f*TTL)	0.182
f/TTL	0.410

Table 8

Table 9

surface	S2	S3	S4	S5	S6	S7
A4	-7.02E-01	-8.19E-02	-2.86E+00	-2.07E+00	-1.06E+00	3.32E-01
A6	1.71E+00	9.78E-01	1.26E+01	4.85E+00	1.89E+00	-1.82E+00
A8	-2.56E+01	-6.35E+00	-3.17E+01	-6.67E+00	-1.80E+00	4.48E+00
A10	1.74E+02	2.31E+01	4.96E+01	5.94E+00	6.00E-01	-5.70E+00
A12	-6.96E+02	-4.49E+01	-4.51E+01	-3.88E+00	4.78E-01	3.92E+00
A14	1.27E+03	4.20E+01	2.15E+01	1.89E+00	-6.05E-01	-1.42E+00
A16	-6.27E+02	-1.05E+01	-4.08E+00	-4.68E-01	1.92E-01	2.15E-01

Based on the parameters shown in Table 7, Table 8 and Table 9, the overall focal length of the three-piece infrared wide-angle lens 110 in Embodiment 3 is f=1.477mm, the F number of the lens 110=1.9, and the maximum field of view angle of the lens 110 is FOV =66°, TTL=3.6mm. It can be seen that the lens 110 in Embodiment 3 has a larger FOV, a smaller working F number, and a smaller lens size (TTL).

FIG. 12 shows the aberration curve of the lens 110; FIG. 13 shows the MTF curve, that is, the OTF module value of the lens 110; FIG. 14 shows the relative illumination of the lens 110. It can be seen from Figures 12 to 14 that when the parameters TTL, f, and Y of the lens 110 meet the above conditions, while the FOV and F number of the lens 110 meet the requirements, the lens 110 also has smaller optical distortion such as distortion. The absolute value of is less than 3%, and the lens 110 has a higher MTF, has higher projection quality, and maintains a higher relative illumination while maintaining a larger FOV.

Example 4

The lens 110 includes three lenses. As shown in FIG. 15 , the lens 110 includes, in order from the imaging side to the light source side: an aperture 114, a first lens 111, a second lens 112 and a third lens 113, and a light source surface 115. The first lens 111 is a lens with positive optical power, the second lens 112 is a lens with negative optical power, and the third lens 113 is a lens with positive optical power.

In order to facilitate distinction and description, in order from the imaging side to the light source side, the imaging surface is marked as S0, the aperture 114 is marked as S1, the two surfaces of the first lens 111 are marked as S2 and S3 respectively, and the second lens 112 The two surfaces of the third lens 113 are marked as S4 and S5 respectively, the two surfaces of the third lens 113 are marked as S6 and S7 respectively, and the light source surface 115 is marked as S8. At least one surface of the lens 110 is an aspherical surface.

Further, by setting the focal length, curvature radius, center thickness, material, cone coefficient and other parameters of each lens in the lens 110, as well as the aspherical higher-order coefficient of the aspheric lens in the lens 110, so that the FOV, F Number, relative illumination, aberration, etc. meet the requirements.

In Embodiment 4, the parameters such as focal length, curvature radius, and center thickness of each lens are set as shown in Table 10. The settings of the curvature radius, thickness, material (n, v) and conic coefficient of each surface in S0 to S8 are shown in Table 11. The settings of the aspherical higher-order term coefficients A4, A6, A8, A10, A12, A14, and A16 of the aspherical surfaces in S2 to S7 are shown in Table 12. In Table 11, the curvature radii of planes such as S0, S1, and S8 are infinite.

Table 10

Table 11

Table 12

surface	S2	S3	S4	S5	S6	S7
A4	-6.93E-01	-1.05E-01	-2.68E+00	-2.02E+00	-1.09E+00	2.87E-01

A6	-2.83E-01	6.58E-01	1.24E+01	4.85E+00	1.77E+00	-1.89E+00
A8	-2.26E+01	-6.38E+00	-3.18E+01	-6.70E+00	-1.76E+00	4.34E+00
A10	1.78E+02	2.37E+01	4.99E+01	5.84E+00	6.03E-01	-5.50E+00
A12	-7.51E+02	-4.53E+01	-4.51E+01	-3.82E+00	4.29E-01	3.85E+00
A14	1.05E+03	2.91E+01	2.09E+01	1.91E+00	-5.93E-01	-1.41E+00

Based on the parameters shown in Table 10, Table 11 and Table 12, the overall focal length of the three-piece infrared wide-angle lens 110 in Embodiment 4 is f=1.429mm, the F number of the lens 110=1.8, and the maximum field of view angle of the lens 110 is FOV =68°, TTL=3.178mm. It can be seen that the lens 110 in Embodiment 4 has a larger FOV, a smaller working F number, and a smaller lens size (TTL).

FIG. 16 shows the aberration curve of the lens 110; FIG. 17 shows the MTF curve, that is, the OTF module value of the lens 110; FIG. 18 shows the relative illumination of the lens 110. It can be seen from Figures 16 to 18 that when the parameters TTL, f, and Y of the lens 110 meet the above conditions, while the FOV and F number of the lens 110 meet the requirements, the lens 110 also has smaller optical distortion such as distortion. The absolute value of is less than 2%, and the lens 110 has a higher MTF, has higher projection quality, and maintains a higher relative illumination while maintaining a larger FOV.

Among them, if the positions corresponding to the parameters in Table 1 to Table 12 are blank, it means that there is no such parameter or the value of the parameter is 0.

The Y, f and TTL of the lens 110 affect the size, FOV, F number, relative illumination, etc. of the lens. In the embodiment of the present application, by designing parameter relationships such as Y/(f*TTL), f/TTL and Y/TTL, the lens 110 can have a larger FOV and a smaller F number, for example, 60°<FOV <85°, F number <2.4. In order to ensure that the lens 110 has good projection capability, the lens 110 is also made to have a smaller size, such as TTL<4.0 or TTL<3.3. And by optimizing the relative illumination, the uniformity of the depth error of the lens 110 in the entire field of view is improved.

In practical applications, a suitable lens can be selected according to the actual situation and meeting the lens parameters of this application. For example, the lenses in Embodiment 1 and 2 have larger FOVs of 80° and 72° respectively, and the lens 110 of Embodiment 2 has a smaller F number, F number = 1.78, while Embodiment 1 The TTL of the lens 110 is smaller, TTL=2.792. As another example, the lenses in Example 3 and Example 4 have smaller F numbers, with F numbers being 1.9 and 1.8 respectively.

It can be seen from Figures 3 to 6, Figures 7 to 10, Figures 11 to 14, and Figures 15 to 18 that the lens 110 of the present application has a larger FOV and a smaller F number, and can meet the needs of larger meet the detection field of view requirements and maintain good projection performance. At the same time, the lens 110 also has smaller optical distortion, and the lens 110 has a higher MTF, has higher projection quality, and maintains a higher relative illumination while maintaining a larger FOV.

It should be noted that, on the premise of no conflict, the various embodiments described in this application and/or the technical features in each embodiment can be combined with each other arbitrarily, and the technical solution obtained after the combination should also fall within the protection scope of this application. .

It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art better understand the embodiments of the present application, but do not limit the scope of the embodiments of the present application. Those skilled in the art can use the above embodiments to Various improvements and deformations are made, and these improvements or deformations fall within the protection scope of the present application.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims (17)

1. An infrared projection lens, characterized in that the lens is composed of an aperture, a first lens, a second lens and a third lens arranged in sequence from the imaging side to the light source side, wherein:

   The first lens is a lens with positive optical power. The first lens is a concave surface on the imaging side of the paraxial axis. The first lens is a convex surface on the light source side of the paraxial axis. Among the two surfaces of the first lens, At least one surface is aspherical;

   The second lens is a lens with negative optical power. The second lens is concave on the imaging side of the paraxial axis and convex on the light source side of the paraxial axis. At least one of the two surfaces of the second lens is is an aspheric surface;

   The third lens is a lens with positive optical power, the third lens is convex on the paraxial imaging side, and at least one of the two surfaces of the third lens is aspherical;

   Wherein, the lens satisfies 0.1<|Y/(f*TTL)|<0.4, where f is the focal length of the lens, Y is the maximum object height of the lens, and TTL is the aperture surface of the lens to The distance between imaging surfaces.
2. The infrared projection lens according to claim 1, characterized in that the lens also satisfies 0.3<f/TTL<0.5.
3. The infrared projection lens according to claim 1 or 2, characterized in that the lens also satisfies 0.2<Y/TTL<0.4.
4. The infrared projection lens according to any one of claims 1 to 3, characterized in that the field of view angle FOV of the lens satisfies 60°<FOV<85°, and/or the F number of the lens satisfies F Number <2.4.
5. The infrared projection lens according to any one of claims 1 to 4, characterized in that the lens satisfies at least one of the following conditions: |Y/(f*TTL)|=0.299, f/TTL=0.416 , Y/TTL=0.347, F number of the lens=2.27, FOV of the lens=80°.
6. The infrared projection lens according to any one of claims 1 to 5, characterized in that the lens satisfies at least one of the following conditions: |Y/(f*TTL)|=0.218, f/TTL=0.410 , Y/TTL=0.295, F number of the lens=1.78, FOV of the lens=72°.
7. The infrared projection lens according to any one of claims 1 to 6, characterized in that the lens satisfies at least one of the following conditions: |Y/(f*TTL)|=0.182, f/TTL=0.410 , Y/TTL=0.269, F number of the lens=1.9, FOV of the lens=66°.
8. The infrared projection lens according to any one of claims 1 to 7, characterized in that the lens satisfies at least one of the following conditions: |Y/(f*TTL)|=0.214, f/TTL=0.450 , Y/TTL=0.305, F number of the lens=1.8, FOV of the lens=68°.
9. The infrared projection lens according to any one of claims 1 to 8, wherein the focal length f ₁ of the first lens and the focal length f ₂ of the second lens satisfy -1.3<f ₂ /f ₁ <-0.5; and/or, the focal length f ₃ of the third lens and the focal length f ₁ of the first lens satisfy 0.3<f ₃ /f ₁ <1.
10. The infrared projection lens according to any one of claims 1 to 9, characterized in that the lens satisfies at least _one of the following conditions: the focal length f of the first lens and the focal length f of the lens. between the focal length f ₂ of the second lens and the focal length f _of the lens satisfies -1.3<f ₂ /f<-0.5; and the focal length f ₃ of the third lens and the focal length f of the lens satisfy 0.4<f ₃ /f<1.1.
11. The infrared projection lens according to any one of claims 1 to 10, characterized in that the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy 0.5<CT1/CT2<1.5 ; and/or, the center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy 0.2<CT2/CT3<1.
12. The infrared projection lens according to any one of claims 1 to 11, wherein the focal length f ₁ of the first lens and the radius of curvature R1 of the imaging side of the first lens satisfy -1<f ₁ /R1<-0.2; and/or, the focal length f ₁ of the first lens and the radius of curvature R2 of the light source side of the first lens satisfy -2.5<f ₁ /R2<-1.5.
13. The infrared projection lens according to any one of claims 1 to 12, wherein the focal length f ₂ of the second lens and the radius of curvature R3 of the imaging side of the second lens satisfy: 2<f ₂ /R3<4.5; the focal length f ₂ of the second lens and the radius of curvature R4 on the light source side of the second lens satisfy 0.4<f ₂ /R4<2.
14. The infrared projection lens according to any one of claims 1 to 13, wherein the focal length _f3 of the third lens and the radius of curvature R5 of the imaging side of the third lens satisfy 1.4< _f3 /R5<1.6; the relationship between the focal length f ₃ of the third lens and the radius of curvature R6 of the light source side of the third lens satisfies -0.2<f ₃ /R6<0.1.
15. The infrared projection lens according to any one of claims 1 to 14, characterized in that the lens satisfies at least one of the following conditions: the curvature radius R1 of the imaging side of the first lens is consistent with the first The radius of curvature R2 on the light source side of the lens satisfies 2<R1/R2<4.5; the radius of curvature R3 on the imaging side of the second lens and the radius of curvature R4 on the light source side of the second lens satisfy 0.2<R3 /R4<0.45; the radius of curvature R5 of the imaging side of the third lens and the radius of curvature R6 of the light source side of the third lens satisfy -0.2<R5/R6<0.1.
16. The infrared projection lens according to any one of claims 1 to 15, wherein the refractive index of the material of the first lens is n ₁ >1.6, and the refractive index of the material of the second lens is n ₂ >1.6. , the refractive index n ₃ of the material of the third lens >1.6; and/or the dispersion coefficient v ₁ of the material of the first lens > 22.0, the dispersion coefficient v ₂ of the material of the second lens > 22.0, The material of the third lens has a dispersion coefficient v ₃ >22.0.
17. The infrared projection lens according to any one of claims 1 to 16, characterized in that the infrared projection lens is used for depth detection.

Images