WO2022052133A1 - Infrared collimating lens and infrared lens module - Google Patents

Abstract

Provided is an infrared collimating lens (110), comprising, sequentially arranged from the imaging side to the light source side, a diaphragm (115), a first lens (111), a second lens (112), and a third lens (113). The first and third lenses (111, 113) have a positive optical power, and the second lens (112) has a negative optical power. The near-axis region of the first lens (111) near the light source side is a concave surface, and the near-axis region near the imaging side is a convex surface; the near-axis region of the second lens (112) near the imaging side is a concave surface; the near-axis region of the third lens (113) near the light source side is a convex surface. At least one of the two surfaces of each lens is a non-spherical surface. Parameters of the lens (110) satisfy: 0.2<|(Y/f)*TTL|<0.8, 0.6<f/TTL<1.4, 0.1<Y/f<0.2, f is the focal length of the lens (110), Y is the maximum object height of the lens (110), and TTL is the distance between the side of the first lens (111) close to the imaging side and the light source.

Description

Infrared collimating lens and infrared lens module technical field

The embodiments of the present application relate to the field of optics, and more particularly, to an infrared collimating lens and an infrared lens module.

Background technique

With the rise of face recognition, somatosensory games and pattern recognition, 3D depth detection has become a hot spot. The 940nm light source is usually used as the signal light source in 3D depth detection. One is to avoid the interference of the visible light band in the sunlight to the signal, and the other is that the water molecules in the air absorb less light of 940 nm. As an important part of the infrared lens module, the infrared collimation lens is very important to the accuracy and field of view of depth detection. Therefore, how to improve the performance of the infrared collimating lens has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

The embodiments of the present application provide an infrared collimating lens and an infrared lens module, and the infrared collimating lens has a larger field of view and a smaller F-number.

In a first aspect, an infrared collimating lens is provided, and the lens includes a first lens, a second lens and a third lens sequentially arranged from the imaging side to the light source side, wherein:

The first lens is a lens with positive refractive power, the first lens is convex in the paraxial region close to the light source side, and is concave in the paraxial region close to the imaging side, the two surfaces of the first lens are At least one face is aspheric;

The second lens is a lens with negative refractive power, the second lens is concave in the paraxial region close to the imaging side, and at least one of the two surfaces of the second lens is aspherical;

The third lens is a lens with positive refractive power, the third lens is convex in the paraxial region close to the light source side, and at least one of the two surfaces of the third lens is aspherical;

The parameters of the lens satisfy: 0.2<|Y/(f*TTL)|<0.8, 0.6<f/TTL<1.4, where f is the focal length of the lens, Y is the maximum object height of the lens, TTL is the distance from the surface of the first lens close to the imaging side to the light source.

In a possible implementation manner, the parameters of the lens also satisfy: 0.1<Y/f<0.2.

In a possible implementation manner, the field of view angle FOV of the lens satisfies: 15°<FOV<30°.

In a possible implementation manner, the F-number of the lens satisfies: F-number<2.85.

In a possible implementation manner, the relative illuminance RI of the lens satisfies: RI>92%.

In one possible implementation, Y/f*TTL=0.49; f/TTL=1.13; Y/f=0.19; FOV=24°; F-number=2.8.

In one possible implementation, Y/f*TTL=0.66; f/TTL=0.84; Y/f=0.18; FOV=24°; F-number=2.84.

In one possible implementation, Y/f*TTL=0.42; f/TTL=1.10; Y/f=0.18; FOV=24°; F-number=2.81.

In one possible implementation, Y/f*TTL=0.35; f/TTL=1.22; Y/f=0.15; FOV=20°; F-number=2.8.

In a possible implementation manner, the relationship between the focal length f ₁ of the first lens and the focal length f ₂ of the second lens satisfies: -0.7<f ₂ /f ₁ <-0.2.

In a possible implementation manner, the relationship between the focal length f ₁ of the first lens and the focal length f ₃ of the third lens satisfies: 0.6<f ₃ /f ₁ <1.2.

In a possible implementation manner, the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 1.2<CT1/CT2<3.0.

In a possible implementation manner, the central thickness CT2 of the second lens and the central thickness CT3 of the third lens satisfy: 0<CT2/CT3<0.6.

In a possible implementation manner, the refractive index n ₁ of the material of the first lens is >1.6.

In a possible implementation manner, the refractive index of the material of the second lens n ₂ >1.6.

In a possible implementation manner, the refractive index of the material of the third lens n ₃ >1.6.

In a possible implementation manner, the focal length f ₁ of the first lens and the focal length f of the lens satisfy: 0.3<f ₁ /f<0.8.

In a possible implementation manner, the relationship between the focal length f ₃ of the third lens and the focal length f of the lens satisfies: 0.2<f ₃ /f<0.6.

In a possible implementation manner, the focal length f ₁ of the first lens and the radius of curvature R1 of the paraxial region of the first lens close to the imaging side satisfy: 2.0<f ₁ /R1<2.5.

In a possible implementation manner, the focal length f ₁ of the first lens and the radius of curvature R2 of the paraxial region of the first lens close to the light source side satisfy: 0.5<f ₁ /R2<1.4.

In a possible implementation manner, the focal length f ₂ of the second lens and the radius of curvature R3 of the paraxial region of the second lens close to the imaging side satisfy: 0.8<f ₂ /R3<1.6.

In a possible implementation manner, the relationship between the focal length f ₂ of the second lens and the radius of curvature R4 of the paraxial region of the second lens close to the light source side satisfies: -0.8<f ₂ /R4<0.

In a possible implementation manner, the focal length f ₃ of the third lens and the radius of curvature R6 of the paraxial region of the third lens close to the imaging side satisfy: -2<f ₃ /R6<-1 .

In a possible implementation manner, the radius of curvature R1 of the first lens in the paraxial region near the imaging side and the radius of curvature R2 of the first lens in the paraxial region near the light source side satisfy: 0.2< R1/R2<0.6.

In a possible implementation manner, the radius of curvature R3 of the second lens in the paraxial region near the imaging side and the radius of curvature R4 of the second lens in the paraxial region near the light source side satisfy: -0.8 <R3/R4<0.

In a possible implementation manner, the lens further includes a diaphragm, and the diaphragm is disposed on a side of the first lens close to the imaging side.

In a possible implementation, the lens is used in depth detection.

In a second aspect, an infrared lens module is provided, including:

The infrared collimating lens according to the first aspect or any possible implementation manner of the first aspect;

And, an array light source with a plurality of light-emitting points.

The light source can be, for example, a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser, VCSEL) light-emitting array.

Based on the above technical solution, the infrared collimating lens includes three lenses. By designing the power and shape of the three lenses, the focal length f of the lens, the maximum object height Y of the lens, and the longitudinal distance TTL between the side of the first lens near the imaging side and the light source satisfy 0.2<|Y /(f*TTL)|<0.8, 0.6<f/TTL<1.4, so it has a larger field of view FOV, a smaller F-number and a larger relative illuminance, thereby improving the viewing angle of the infrared collimating lens. field and precision.

Description of drawings

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

FIG. 2 is a schematic diagram of a collimated optical path of a lens in the infrared lens module shown in FIG. 1 .

FIG. 3 is a schematic diagram of an infrared collimating lens according to an embodiment of the present application.

FIG. 4 is a schematic diagram of a layout of a lens according to an embodiment of the present application.

FIG. 5 is a schematic diagram of an astigmatic aberration curve of the lens shown in FIG. 4 .

FIG. 6 is a schematic diagram of a distortion curve of the lens shown in FIG. 4 .

FIG. 7 is a schematic diagram of the MTF curve of the lens shown in FIG. 4 .

FIG. 8 is a schematic diagram of a curve of relative illuminance of the lens shown in FIG. 4 .

FIG. 9 is a schematic diagram of another layout of a lens according to an embodiment of the present application.

FIG. 10 is a schematic diagram of an astigmatic aberration curve of the lens shown in FIG. 9 .

FIG. 11 is a schematic diagram of the distortion curve of the lens shown in FIG. 9 .

FIG. 12 is a schematic diagram of the MTF curve of the lens shown in FIG. 9 .

FIG. 13 is a schematic diagram of a curve of relative illuminance of the lens shown in FIG. 10 .

FIG. 14 is a schematic diagram of another layout of the lens according to the embodiment of the present application.

FIG. 15 is a schematic diagram of an astigmatic aberration curve of the lens shown in FIG. 14 .

FIG. 16 is a schematic diagram of a distortion curve of the lens shown in FIG. 14 .

FIG. 17 is a schematic diagram of the MTF curve of the lens shown in FIG. 14 .

FIG. 18 is a schematic diagram of a curve of relative illuminance of the lens shown in FIG. 14 .

FIG. 19 is a schematic diagram of another layout of the lens according to the embodiment of the present application.

FIG. 20 is a schematic diagram of an astigmatic aberration curve of the lens shown in FIG. 19 .

FIG. 21 is a schematic diagram of a distortion curve of the lens shown in FIG. 19 .

FIG. 22 is a schematic diagram of the MTF curve of the lens shown in FIG. 19 .

FIG. 23 is a schematic diagram of a relative illuminance curve of the lens shown in FIG. 19 .

detailed description

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

FIG. 1 is a schematic structural diagram of an infrared lens module according to an embodiment of the present application. As shown in FIG. 1 , the infrared lens module 100 at least includes an infrared collimating lens (hereinafter referred to as a lens) 110 , a lens barrel 120 and a light source 130 .

The lens 110 is a signal collection part, and is the core component of the infrared lens module 100 , which may be an optical structure composed of a spherical surface or an aspherical surface, and is used to focus the incident light onto the photosensitive chip. The lens 110 may be formed by a combination of one or more lenses, and each lens may be, for example, injection-molded by using materials such as resin.

The lens barrel 120 (Barrel) is a non-light-absorbing support for fixing the lens 110 .

It should be understood that the structure of the infrared lens module 100 shown in FIG. 1 is only an example, and the embodiment of the present application mainly improves the lens 110 therein, and does not limit the positions and parameters of other structures and devices.

As shown in FIG. 2 , the lens 110 includes an imaging surface 116 , an optical axis 117 , a diaphragm 115 , a lens 111 , a lens 112 , a lens 113 and a light source surface 114 . For example, the lens 110 in the embodiment of the present application may use, for example, a semiconductor laser light source or other laser light sources. Taking the light in the central field of view as an example, the light emitted by the light source surface 114 is condensed by the collimating lens group to form parallel light successively, and is finally projected onto the imaging surface 116 .

The embodiment of the present application designs an infrared collimating lens, which has a larger field of view and a smaller F-number, so that the infrared collimating lens has better performance.

In order to facilitate better understanding, the parameter indicators designed in the embodiments of the present application that may be used for evaluating the performance of the infrared collimating lens are briefly introduced first.

Field of View (FOV): It is used to characterize the field of view of the lens. In the case of the same lens size, the larger the FOV of the lens, the more information that the lens can obtain, that is, the lens can obtain the information of a larger area. more information.

Working F-number, or F-number (F-number, Fno): that is, the reciprocal of the relative aperture of the lens, which is used to characterize the amount of light entering the photosensitive chip through the lens. The smaller the F-number, the greater the amount of light entering the lens.

TV Distortion: It is used to measure the degree of visual distortion of the image. Understandably, the smaller the TV distortion, the better the lens.

Relative Illumination (RI): refers to the ratio of the illuminance of different coordinate points on the imaging surface to the illuminance of the center point. The problem of exposure affects the image quality; the greater the relative illumination, the higher the image quality.

The lens 110 in the infrared lens module 100 shown in FIG. 1 is shown in FIG. 3 . The lens 110 includes a first lens 111 , a second lens 112 , and a first lens 111 , a second lens 112 and a first lens 111 , which are sequentially arranged from the imaging side (the light-emitting side of the module) to the light source side. Three lenses 113 .

The first lens 111 is a lens with positive refractive power. The first lens 111 is convex in the paraxial region near the imaging side, and concave in the paraxial region near the light source, and at least one of the two surfaces of the first lens 111 is aspheric.

The second lens 112 is a lens with negative refractive power. The paraxial region of the second lens 112 near the imaging side is concave, and at least one of the two surfaces of the second lens 112 is aspheric.

The third lens 113 is a lens with positive refractive power. The paraxial region of the third lens 113 near the light source side is convex, and at least one of the two surfaces of the third lens 113 is aspheric.

It should be understood that "the lens is in the paraxial region near the light source side" described in the embodiments of the present application can also be expressed as "the lens is in the light source side of the paraxial region"; "the lens is in the paraxial region near the imaging side", It can also be expressed as "the lens is on the imaging side of the paraxial region". For example, the first lens 111 is convex in the paraxial region close to the imaging side, that is, the first lens 111 is convex in the imaging side of the paraxial region.

It should also be understood that the "paraxial" or "paraxial region" of the lens may refer to the region of the paraxial light having an included angle θ with the optical axis, where θ satisfies: θ≈sinθ. For example, θ may be less than 5°.

For example, the first lens 111 , the second lens 112 and the third lens 113 can be injection-molded by using resin materials or other plastic materials, which are not limited here.

Wherein, the focal length f of the lens 110, the maximum object height Y of the lens 110, and the distance from the side of the first lens 111 close to the imaging side to the light source, that is, the total longitudinal length (Total Trace Length, TTL) of the lens 110, satisfy the predetermined conditions , so that the lens 110 has a larger FOV, a smaller F-number, and a larger relative illuminance.

The preset condition is, for example, at least one of the following conditions: 0.2<|Y/(f*TTL)|<0.8, 0.6<f/TTL<1.4, and 0.1<Y/f<0.2.

In the embodiment of the present application, a three-piece lens is used as the signal collecting device, and the lens includes three lenses. By designing the power and shape of the three lenses, the f, Y and TTL of the lens meet the preset conditions, so that the lens has a larger FOV and a smaller F number without increasing the infrared accuracy. The vertical space occupied by the straight lens when assembled in the electronic equipment improves the field of view and the precision of the infrared collimating lens under the condition of satisfying the increasingly tight size constraints of the electronic equipment.

For example, the infrared collimating lens can be applied to depth detection, so as to realize the depth detection of the target by using infrared light.

Further, in the depth detection, the infrared collimation lens can realize the collimation of light, and the divergence angle of the light spot emitted by the light source after passing through the infrared collimation lens can be smaller than, for example, 0.1°, thereby ensuring the collimation effect. In the embodiment of the present application, a surface light source may be used to form an infrared lens consisting of a vertical resonant cavity surface emitting laser (VCSEL) light-emitting array, the above-mentioned collimator and diffuser, etc. module or near-infrared lens module.

The f, Y, and TTL of the lens 110 affect the FOV and F number of the lens, and f, Y, and TTL also affect each other. Therefore, by controlling the relationship between f, Y, and TTL to satisfy the preset relationship, the lens 110 can have The larger FOV and smaller F-number meet the collimation requirements of the lens, further enabling the photosensitive chip 150 to obtain more light carrying target information, maximizing the use of the effective photosensitive area of the photosensitive chip 150, thereby improving the resolution and precision.

When the f, Y, and TTL of the lens 110 meet the preset conditions, the FOV, F number, relative illuminance, etc. of the lens 110 can be made to meet the requirements. For example, make the FOV of the lens 110 satisfy: 15°<FOV<30° to achieve a balance between the accuracy requirement of depth detection and the field of view requirement; for another example, make the F-number of the lens 110 satisfy: F-number<2.85 to achieve a weak Signal detection and shorten the exposure time; for another example, the relative illuminance of the lens 110 satisfies: RI>92%, so as to improve the uniformity of the depth error in the entire field of view, and further, the uniformity of the lens 110 can reach 2.5%. In addition, the lens 110 may also have a smaller size, eg, a TTL smaller than 3.7mm.

The conditions that the parameters of the lens 110 should meet are described above as a whole, and the following describes the respective parameter designs of the first lens 111 , the second lens 112 and the third lens 113 in the lens 110 . When the parameters of each lens satisfy some or all of the following conditions, the FOV and F-number of the lens 110 may satisfy 15°<FOV<30°, F-number<2.85, and RI>92%, respectively.

For the first lens 111 , optionally, a certain relationship is satisfied between the focal length f ₁ of the first lens 111 and the radius of curvature of the first lens 111 . For example, the focal length f ₁ and the curvature radius R1 of the paraxial region near the imaging side of the first lens 111 satisfy 2.0<f ₁ /R1<2.5; for another example, the distance between the focal length f ₁ and the first lens 111 near the light source side The radius of curvature R2 of the paraxial region satisfies 0.5<f ₁ /R2<1.4.

For the second lens 112 , optionally, a certain relationship is satisfied between the focal length f ₂ of the second lens 112 and the radius of curvature of the second lens 112 . For example, 0.8<f ₂ /R3<1.6 is satisfied between the focal length f ₂ and the radius of curvature R3 of the paraxial region of the second lens 112 on the imaging side; for another example, the focal length f ₂ and the second lens 112 on the side of the light source are close to the light source. The radius of curvature R4 of the paraxial region satisfies -0.8<f ₂ /R4<0.

For the third lens 113 , optionally, a certain relationship is satisfied between the focal length f ₃ of the third lens 113 and the curvature radius of the third lens 113 . For example, -2<f ₃ /R6<-1 is satisfied between the focal length f ₃ and the curvature radius R 6 of the paraxial region of the third lens 113 near the light source side.

For each lens, there are two surfaces respectively close to the light source side and the imaging side. Optionally, a certain relationship is satisfied between the curvature radii of the two surfaces. For example, the radius of curvature R1 of the paraxial region of the first lens 111 near the imaging side and the radius of curvature R2 of the paraxial region of the first lens 111 near the light source side satisfy 0.2<R1/R2<0.6; -0.8<R3/R4<0 between the curvature radius R3 of the paraxial region of the second lens 112 near the imaging side and the curvature radius R4 of the paraxial region of the second lens 112 near the light source side.

It can be seen that by designing the respective focal lengths and curvature radii of the three lenses, the FOV of the lens 110 can meet the requirements, and the length and weight of the lens 110 can be effectively reduced so that they can be mounted on thin and light electronic products, while reducing aberrations and increasing The field of view of the lens, thereby effectively improving the performance of the lens 110 .

In the embodiment of the present application, the first lens 111 and the third lens 113 are lenses with positive refractive power (positive refractive power), and the second lens 112 is a lens with negative refractive power (negative refractive power). Specifically, for the power distribution between lenses, the following relationship exists between the respective focal lengths of the first lens 111 , the second lens 112 and the third lens 113 and the focal length f of the lens 110 . In this case, the length of the lens 110 is shortened, the sensitivity of the lens 110 is reduced, and the product yield is improved.

For example, the focal length f ₁ of the first lens 111 and the focal length f of the lens 110 satisfy 0.3<f ₁ /f<0.8; for another example, the focal length f ₃ of the third lens 113 and the focal length f of the lens 110 satisfy 0.2< f ₃ /f<0.6.

In addition, by adjusting the focal length ratio between the first lens 111 , the second lens 112 and the third lens 113 , aberrations can be effectively reduced. For example, the focal length f 1 of the first lens 111 and the focal length f ₂ of the second lens 112 satisfy -0.7<f ₂ /f ₁ <-0.2; for another example, the focal length f ₁ of the _first lens 111 and the third lens The focal length f ₃ and 112 satisfy 0.6<f ₃ /f ₁ <1.2.

In order to ensure the formability and uniformity of the lens, make the structure of the lens 110 stronger, and improve 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 lens along the The thickness in the optical axis direction is designed.

For example, the center thickness CT1 of the first lens 111 and the center thickness CT2 of the second lens satisfy 1.2<CT1/CT2<3.0; for another example, the center thickness CT2 of the second lens 112 and the center thickness CT3 of the third lens 113 satisfy The time satisfies 0<CT2/CT3<0.6.

In addition, in order to meet the dispersion requirements, reduce the production cost, and provide a suitable aberration balance, the refractive indices of the materials of the first lens 111 , the second lens 112 and the third lens 113 may also be designed.

For example, the refractive index of the material of the first lens 111 is n1>1.6; for another example, the refractive index of the material of the second lens 112 is n2>1.6; for example, the refractive index of the material of the third lens 113 is n3>1.6.

Optionally, in some implementations, the lens 110 further includes a diaphragm 115, which may also be called an aperture. The diaphragm 115 may be provided, for example, on the side of the first lens 111 close to the imaging side.

The aperture 115 can be used to adjust the size of the light range. By setting the aperture 115 to adjust the light range, the light carrying the target information can be retained to the greatest extent, so that the photosensitive chip can obtain more target information and further improve the infrared lens model. The resolving power of the group's depth detection of the target.

In this embodiment of the present application, various components in the lens 110 can be controlled by controlling physical parameters such as the radius of curvature, thickness, material, and focal length of the first lens, the second lens, the third lens, and the diaphragm, and/or the The even-order term in the aspheric high-order term coefficient of the aspheric lens in the lens 110, etc., make the parameters of the lens 110 satisfy the above-mentioned preset relationship, and then make the FOV of the lens 110 satisfy 15°<FOV<30°, F number Less than 2.85, relative illuminance RI>92%. Hereinafter, some possible specific forms of the lens 110 in the embodiments of the present application will be described in detail by taking Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 as examples. The infrared collimating lens in Embodiments 1 to 4 adopts 3-piece plastic aspherical lenses, which can form, for example, an infrared single-wavelength collimating lens group, thereby realizing infrared collimation with high-quality image sensing function and ultra-low height lens.

Example 1

The lens 110 includes three lenses, as shown in the layout of each lens in FIG. 4 , in which, from the imaging side to the light source side, are: a diaphragm 115 , a first lens 111 , a second lens 112 and a third lens 113 and the light source surface 114.

For the convenience of distinction and description, in the order from the imaging side to the light source side, the imaging surface is denoted as S0, the diaphragm 115 is denoted as S1, the two surfaces of the first lens 111 are denoted as S2 and S3, respectively, and the second lens 112 The two surfaces of the lens 113 are denoted as S4 and S5 respectively, the two surfaces of the third lens 113 are denoted as S6 and S7 respectively, and the light source surface 114 is denoted as S8.

Further, by setting at least one of parameters such as the focal length, center thickness, radius of curvature, material, etc. of each lens in the lens 110, and the aspheric high-order coefficient of the aspheric lens in the lens 110, the FOV of the lens 110 is set. , F number and relative illuminance meet the requirements.

In Example 1, the settings of the relationship among the focal length, radius of curvature, and center thickness of each lens are shown in Table 1. The settings of the radius of curvature, thickness, material (refractive index, dispersion rate), and focal length of each surface in S0 to S8 are shown in Table 2, where the thickness of the imaging surface can represent, for example, the distance between the imaging surface and the lens 110, that is, the target The projected distance. The settings of the aspheric higher-order coefficients A2, A4, A6, A8, A10, A12, A14, A16, and A18 of the aspheric surfaces in S2 to S7 are shown in Table 3, where the coefficients of A2 are all 0, and the parameter K is Conic constant.

Table 1

Table 2

table 3

surface	S2	S3	S4	S5	S6	S7
K	-3.80E-01	0.00E+00	-8.42E+00	8.46E-05	-2.05E+00	-5.00E-01
A4	1.36E-01	1.75E-01	-2.31E+00	3.95E+00	2.47E-01	-4.87E-01
A6	4.81E-01	8.62E-02	-3.68E+01	-8.59E-01	1.99E+00	6.21E+00
A8	-4.91E-01	-7.69E+00	1.24E+03	-4.80E+02	-1.90E+01	-3.71E+01
A10	-1.72E+00	8.78E+01	-2.66E+04	6.53E+03	8.24E+01	1.19E+02
A12	3.71E+01	-4.27E+02	2.15E+05	-4.34E+04	-1.64E+02	-2.12E+02
A14	-7.12E+01	6.29E+02	-1.03E+06	1.13E+05	1.69E+02	1.73E+02
A16	0.00E+00	0.00E+00	0.00E+00	-9.33E+04	-6.86E+01	-6.87E+00
A18	0.00E+00	0.00E+00	0.00E+00	0.00E+00	0.00E+00	-4.71E+01

Based on the parameters shown in Table 1, Table 2 and Table 3, the parameters of the lens 110 shown in Embodiment 1 can be determined as follows: TTL=2.7mm, f=3.00mm, F-number=2.8, FOV=24°.

Fig. 5 shows the astigmatism curve of the lens 110; Fig. 6 shows the distortion curve of the lens 110; Fig. 7 shows the Modulation Transfer Function (MTF) curve of the lens 110; 8 shows the relative illuminance of the lens 110. It can be seen from the simulation diagrams shown in FIG. 5 to FIG. 8 that when the parameters TTL, f, and Y of the lens 110 meet the above preset conditions, the lens 110 has a larger FOV, a smaller working F number, and a higher Small lens size (TTL), less TV distortion, and greater relative illumination, and the lens performs better.

Example 2

The lens 110 includes three lenses, as shown in the layout of each lens in FIG. 9 , wherein, from the imaging side to the light source side are: diaphragm 115 , first lens 111 , second lens 112 , third lens 113 and light source surface 114.

For the convenience of distinction and description, in the order from the imaging side to the light source side, the imaging surface is denoted as S0, the diaphragm 115 is denoted as S1, the two surfaces of the first lens 111 are denoted as S2 and S3, respectively, and the second lens 112 The two surfaces of the lens 113 are denoted as S4 and S5 respectively, the two surfaces of the third lens 113 are denoted as S6 and S7 respectively, and the light source surface 114 is denoted as S8.

Further, by setting at least one of the parameters such as the focal length, center thickness, radius of curvature, material, etc. of each lens in the lens 110, and the aspheric high-order coefficient of the aspheric lens in the lens 110, so that the FOV of the lens 110 is set. , F number and relative illuminance meet the requirements.

In Example 2, the settings of the relationship among the focal length, radius of curvature, and center thickness of each lens are shown in Table 4. The settings of the radius of curvature, thickness, material (refractive index, dispersion rate), and focal length of each surface in S0 to S8 are shown in Table 5, where the thickness of the imaging surface can, for example, represent the distance between the imaging surface and the lens 110, that is, the target The projected distance. The settings of the aspheric high-order coefficients A2, A4, A6, A8, A10, A12, A14, A16, and A18 of the aspheric surfaces in S2 to S7 are shown in Table 6. The coefficients of A2 are all 0, and the parameter K is Conic constant.

Table 4

table 5

Table 6

surface	S2	S3	S4	S5	S6	S7
K	0.00E+00	0.00E+00	-1.95E+00	-3.00E-01	0.00E+00	-5.00E-01
A4	9.33E-03	1.75E-01	-3.58E-01	1.73E-01	-1.30E+00	-3.10E-02
A6	3.46E-02	8.62E-02	6.62E+00	1.31E+01	6.32E+00	-6.99E-02
A8	1.12E-01	-7.69E+00	-9.69E+01	-9.24E+01	-2.69E+01	3.18E-01
A10	-2.92E-01	8.78E+01	4.67E+02	3.78E+02	9.21E+01	-8.93E-01
A12	3.40E+00	-4.27E+02	-5.89E+02	-3.73E+02	-2.00E+02	1.61E+00
A14	-9.12E+00	6.29E+02	-3.05E+03	-2.18E+03	2.33E+02	-1.62E+00
A16	1.59E+01	0.00E+00	5.87E+07	4.11E+03	-1.11E+02	7.88E-01
A18	0.00E+00	0.00E+00	0.00E+00	0.00E+00	0.00E+00	1.13E+05

Based on the parameters shown in Table 4, Table 5 and Table 6, the parameters of the lens 110 shown in Embodiment 1 can be determined as follows: TTL=3.6mm, f=3.00mm, F-number=2.84, FOV=24°.

FIG. 10 shows the astigmatism curve of the lens 110; FIG. 11 shows the distortion curve of the lens 110; FIG. 12 shows the MTF curve of the lens 110; FIG. 13 shows the relative illuminance of the lens 110 . It can be seen from the simulation diagrams shown in FIG. 10 to FIG. 13 that when the parameters f, Y and TTL of the lens 110 meet the above preset conditions, the lens 110 has a larger FOV, a smaller working F number, and a higher FOV. Small lens size, less TV distortion, and greater relative illumination, and the lens performs better.

Example 3

The lens 110 includes three lenses, as shown in the layout of each lens in FIG. 14 , wherein, from the imaging side to the light source side are: diaphragm 115 , first lens 111 , second lens 112 , third lens 113 and light source surface 114.

For the convenience of distinction and description, in the order from the imaging side to the light source side, the imaging surface is denoted as S0, the diaphragm 115 is denoted as S1, the two surfaces of the first lens 111 are denoted as S2 and S3, respectively, and the second lens 112 The two surfaces of the lens 113 are denoted as S4 and S5 respectively, the two surfaces of the third lens 113 are denoted as S6 and S7 respectively, and the light source surface 114 is denoted as S8.

Further, by setting at least one of the parameters such as the focal length, center thickness, radius of curvature, material, etc. of each lens in the lens 110, and the aspheric high-order coefficient of the aspheric lens in the lens 110, so that the FOV of the lens 110 is set. , F number and relative illuminance meet the requirements.

In Example 3, the settings of the relationship among the focal length, radius of curvature, and center thickness of each lens are shown in Table 7. The settings of the radius of curvature, thickness, material (refractive index, dispersion rate), and focal length of each surface in S0 to S8 are shown in Table 8, where the thickness of the imaging surface can, for example, represent the distance between the imaging surface and the lens 110, that is, the target The projected distance. The settings of the aspheric higher-order coefficients A2, A4, A6, A8, A10, A12, A14, A16, and A18 of the aspheric surfaces in S2 to S7 are shown in Table 9, where the coefficients of A2 are all 0, and the parameter K is Conic constant.

Table 7

Table 8

Table 9

surface

S2

S3

S4

S5

S6

S7

K	0.00E+00	0.00E+00	5.52E-01	4.36E+00	0.00E+00	-5.00E-01
A4	2.31E-02	-1.31E-01	-2.23E+00	-1.18E+02	-1.87E-01	-7.35E-01
A6	-6.55E+00	1.34E+01	8.36E+01	3.06E+03	5.43E+00	1.79E+00
A8	1.17E+02	-2.99E+02	-6.81E+03	-4.13E+04	-4.16E+01	4.56E+00
A10	-1.12E+03	3.33E+03	5.81E+05	2.61E+05	1.99E+02	-2.85E+01
A12	5.08E+03	-1.97E+04	-3.12E+06	-6.92E+05	-5.52E+02	-6.21E+01
A14	-9.35E+03	4.33E+04	1.74E+07	5.81E+05	7.76E+02	6.23E+02
A16	0.00E+00	0.00E+00	0.00E+00	-9.33E+04	-4.54E+02	-1.29E+03
A18	0.00E+00	0.00E+00	0.00E+00	0.00E+00	4.46E+01	8.40E+02

Based on the parameters shown in Table 7, Table 8 and Table 9, the parameters of the lens 110 shown in Embodiment 3 can be determined as follows: TTL=2.32mm, f=2.55mm, F-number=2.81, FOV=24°.

FIG. 15 shows the astigmatism curve of the lens 110; FIG. 16 shows the distortion curve of the lens 110; FIG. 17 shows the MTF curve of the lens 110; FIG. 18 shows the relative illuminance of the lens 110 . It can be seen from the simulation diagrams shown in FIG. 15 to FIG. 18 that when the parameters f, Y and TTL of the lens 110 meet the above preset conditions, the lens 110 has a larger FOV, a smaller working F number, and a higher FOV. Small lens size, less TV distortion, and greater relative illumination, and the lens performs better.

Example 4

The lens 110 includes three lenses, as shown in the layout of each lens in FIG. 19 , in which, from the imaging side to the light source side are: diaphragm 115 , first lens 111 , second lens 112 , third lens 113 and light source surface 114.

For the convenience of distinction and description, in the order from the imaging side to the light source side, the imaging surface is denoted as S0, the diaphragm 115 is denoted as S1, the two surfaces of the first lens 111 are denoted as S2 and S3, respectively, and the second lens 112 The two surfaces of the lens 113 are denoted as S4 and S5 respectively, the two surfaces of the third lens 113 are denoted as S6 and S7 respectively, and the light source surface 114 is denoted as S8.

Further, by setting at least one of the parameters such as the focal length, center thickness, radius of curvature, material, etc. of each lens in the lens 110, and the aspheric high-order coefficient of the aspheric lens in the lens 110, so that the FOV of the lens 110 is set. , F number and relative illuminance meet the requirements.

In Example 4, the settings of the relationship among the focal length, curvature radius, and center thickness of each lens are shown in Table 10. The settings of the radius of curvature, thickness, material (refractive index, dispersion rate), and focal length of each surface in S0 to S8 are shown in Table 11, where the thickness of the imaging surface can, for example, represent the distance between the imaging surface and the lens 110, that is, the target The projected distance. The settings of the aspheric high-order coefficients A2, A4, A6, A8, A10, A12, A14, A16, and A18 of the aspheric surfaces in S2 to S7 are shown in Table 12. The coefficients of A2 are all 0, and the parameter K is Conic constant.

Table 10

project	parameter value
f 1 /f	0.49
f 2 /f	-0.15
f 3 /f	0.29
f 2 /f 1	-0.30
f 3 /f 1	0.60
f 1 /R1	2.35
f 1 /R2	0.95
f 2 /R3	1.54
f 2 /R4	-0.05
f3 /R5	0.37
f3 /R6	-1.33
CT1/CT2	1.56
CT2/CT3	0.52
R1/R2	0.41
R3/R4	-0.03
R5/R6	-3.55
Y/f	0.15
Y/TTL	0.18
Y/f*TTL	0.35
f/TTL	1.22

Table 11

Table 12

surface	S2	S3	S4	S5	S6	S7
K	0.00E+00	0.00E+00	6.16E+00	0.00E+00	0.00E+00	-5.00E-01
A4	4.27E-01	-1.25E+00	-1.29E+03	-1.47E+01	-3.75E+00	-6.12E-01
A6	-1.95E+01	1.69E+01	4.92E+04	4.15E+02	1.24E+01	5.17E+01
A8	2.32E+02	-2.30E+02	-9.67E+05	-8.41E+03	-9.90E+00	-1.28E+03
A10	-1.53E+03	1.45E+03	9.91E+06	1.03E+05	2.42E+02	1.46E+04
A12	4.91E+03	-4.88E+03	-4.08E+07	-6.17E+05	-5.78E+02	-9.27E+04
A14	-6.54E+03	6.82E+03	-3.05E+03	1.59E+06	-1.87E+02	3.34E+05
A16	1.59E+01	0.00E+00	5.87E+07	-1.32E+06	-7.23E+03	-6.36E+05
A18	0.00E+00	0.00E+00	0.00E+00	0.00E+00	4.71E+03	4.93E+05

Based on the parameters shown in Table 10, Table 11 and Table 12, the parameters of the lens 110 shown in Embodiment 4 can be determined as follows: TTL=2.3mm, f=2.80mm, F-number=2.8, FOV=20°.

FIG. 20 shows the astigmatism curve of the lens 110; FIG. 21 shows the distortion curve of the lens 110; FIG. 22 shows the MTF curve of the lens 110; FIG. 23 shows the relative illuminance of the lens 110 . It can be seen from the simulation diagrams shown in FIG. 20 to FIG. 23 that when the parameters f, Y and TTL of the lens 110 meet the above preset conditions, the lens 110 has a larger FOV, a smaller working F number, and a higher Small lens size, less TV distortion, and greater relative illumination, and the lens performs better.

Wherein, the positions corresponding to the parameters in Table 1 to Table 12 are blank, indicating that there is no such parameter or the value of this parameter is 0.

The Y', f, and TTL of the lens 110 affect the size, FOV, F-number, relative illumination, etc. of the lens. The space size of the lens 110, that is, TTL, directly affects the design difficulty of the lens 110. In the embodiment of the present application, by designing Y'/(f*TTL) and f/TTL, the lens 110 can have a smaller TTL, such as TTL <3.7, especially in Examples 3 and 4, the TTL is less than 2.4. Under the condition of ensuring that the lens 110 has a good resolution, it is avoided to occupy a large space size. In addition, the field of view FOV of the lens 110 is also related to Y/f. By designing Y/f, the lens 110 can have a larger field of view FOV, so as to meet the increasingly tight size constraints of electronic equipment. , which improves the field of view and accuracy of the infrared collimating lens.

On the other hand, the lens 110 of the present application has a larger field of view, and a balance is achieved between the size of the apertures corresponding to the collimating lens groups formed by the lenses in the lens 110 .

By optimizing the relative illumination, the uniformity of the depth error of the lens 110 within the full field of view is also improved.

In addition, the lens 110 also has better parallelism of light output, which increases the accuracy and recognition speed of depth detection.

It should be noted that, on the premise of no conflict, each embodiment described in this application and/or the technical features in each embodiment can be arbitrarily combined with each other, 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 to better understand the embodiments of the present application, rather than limiting the scope of the embodiments of the present application, and those skilled in the art can Various improvements and modifications can be made, and these improvements or modifications all fall within the protection scope of the present application.

The above are only specific implementations of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims (26)

1. An infrared collimating lens, characterized in that the lens comprises a first lens, a second lens and a third lens in sequence from the imaging side to the light source side, wherein:

   The first lens is a lens with positive refractive power, the first lens is convex in the paraxial region close to the imaging side, and is concave in the paraxial region close to the light source side, the two surfaces of the first lens are At least one face is aspheric;

   The second lens is a lens with negative refractive power, the second lens is concave in the paraxial region close to the imaging side, and at least one of the two surfaces of the second lens is aspherical;

   The third lens is a lens with positive refractive power, the third lens is convex in the paraxial region close to the light source side, and at least one of the two surfaces of the third lens is aspherical;

   Wherein, the parameters of the lens satisfy: 0.2<|Y/(f*TTL)|<0.8, 0.6<f/TTL<1.4, 0.1<Y/f<0.2, where f is the focal length of the lens, Y is the maximum object height of the lens, and TTL is the distance from the surface of the first lens close to the imaging side to the light source.
2. The infrared collimating lens according to claim 1, wherein the FOV of the lens satisfies: 15°<FOV<30°.
3. The infrared collimating lens according to claim 1 or 2, wherein the F-number of the lens satisfies: F-number<2.85.
4. The infrared collimating lens according to any one of claims 1 to 3, characterized in that, Y/f*TTL=0.49; f/TTL=1.13; Y/f=0.19; FOV=24°; F number= 2.8.
5. The infrared collimating lens according to any one of claims 1 to 4, characterized in that, Y/f*TTL=0.66; f/TTL=0.84; Y/f=0.18; FOV=24°; F number= 2.84.
6. The infrared collimating lens according to any one of claims 1 to 5, characterized in that, Y/f*TTL=0.42; f/TTL=1.10; Y/f=0.18; FOV=24°; F number= 2.81.
7. The infrared collimating lens according to any one of claims 1 to 6, characterized in that, Y/f*TTL=0.35; f/TTL=1.22; Y/f=0.15; FOV=20°; F number= 2.8.
8. The infrared collimating lens according to any one of claims 1 to 7, wherein the focal length f ₁ of the first lens and the focal length f ₂ of the second lens satisfy: -0.7<f ₂ /f ₁ <-0.2.
9. The infrared collimating 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 ₃ of the third lens satisfy: 0.6<f ₃ /f ₁ < 1.2.
10. The infrared collimating lens according to any one of claims 1 to 9, wherein the central thickness CT1 of the first lens and the central thickness CT2 of the second lens satisfy: 1.2<CT1/CT2 <3.0.
11. The infrared collimating lens according to any one of claims 1 to 10, wherein the central thickness CT2 of the second lens and the central thickness CT3 of the third lens satisfy: 0<CT2/CT3 <0.6.
12. The infrared collimating lens according to any one of claims 1 to 11, wherein the material of the first lens has a refractive index n ₁ >1.6.
13. The infrared collimating lens according to any one of claims 1 to 12, wherein the material of the second lens has a refractive index n ₂ >1.6.
14. The infrared collimating lens according to any one of claims 1 to 13, wherein the refractive index of the material of the third lens is n ₃ >1.6.
15. The infrared collimating lens according to any one of claims 1 to 14, wherein the focal length f ₁ of the first lens and the focal length f of the lens satisfy: 0.3<f ₁ /f<0.8 .
16. The infrared collimating lens according to any one of claims 1 to 15, wherein the focal length f ₃ of the third lens and the focal length f of the lens satisfy: 0.2<f ₃ /f<0.6 .
17. The infrared collimating lens according to any one of claims ₁ to 16, wherein the focal length f1 of the first lens is between the radius of curvature R1 of the paraxial region of the first lens near the imaging side satisfies: 2.0<f ₁ /R1<2.5.
18. The infrared collimating lens according to any one of claims ₁ to 17, wherein the focal length f1 of the first lens is between the curvature radius R2 of the paraxial region of the first lens near the light source side satisfies: 0.5<f ₁ /R2<1.4.
19. The infrared collimating lens according to any one of claims 1 to 18, wherein the focal length f2 of the _second lens is between the curvature radius R3 of the second lens in the paraxial region near the imaging side time to satisfy: 0.8<f ₂ /R3<1.6.
20. The infrared collimating lens according to any one of claims 1 to 19, wherein the focal length f2 of the _second lens is between the radius of curvature R4 of the paraxial region of the second lens near the light source side time to satisfy: -0.8<f ₂ /R4<0.
21. The infrared collimating lens according to any one of claims 1 to 20, wherein the focal length _f3 of the third lens is between the curvature radius R6 of the third lens in the paraxial region near the imaging side satisfies: -2<f ₃ /R6<-1.
22. The infrared collimating lens according to any one of claims 1 to 21, wherein the curvature radius R1 of the paraxial region of the first lens near the imaging side is the same as that of the first lens near the light source side. The radius of curvature R2 of the paraxial region satisfies: 0.2<R1/R2<0.6.
23. The infrared collimating lens according to any one of claims 1 to 22, wherein the curvature radius R3 of the paraxial region of the second lens near the imaging side is the same as the radius of curvature R3 of the second lens near the light source side The radius of curvature R4 of the paraxial region satisfies: -0.8<R3/R4<0.
24. The infrared collimating lens according to any one of claims 1 to 23, further comprising a diaphragm, the diaphragm being disposed on the side of the first lens close to the imaging side.
25. The infrared collimating lens according to any one of claims 1 to 24, wherein the infrared collimating lens is applied in depth detection.
26. An infrared lens module, comprising:

    The infrared collimating lens of any one of claims 1 to 25; and,

    An array light source with multiple light-emitting points.

Images