WO2021082223A1 - High-pixel infrared optical system and applied camera module thereof - Google Patents

Abstract

A high-pixel infrared optical system, comprising a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) sequentially arranged from an object plane to an image plane along an optical axis. The object plane side of the first lens (1) is a convex surface and the image plane side is a concave surface, and the focal power thereof is negative. The object plane side of the second lens (2) is a convex surface and the image plane side is a concave surface, and the focal power thereof is positive. The object plane side of the third lens (3) is a concave surface and the image plane side is a convex surface, and the focal power thereof is positive. The object plane side of the fourth lens (4) is a convex surface and the image plane side is a concave surface. Also provided is a camera module. According to the optical system and the camera module, the system is mainly composed of four lenses; and because of a few of lenses, the structure of the system is simplified. On the basis of mutual combination of different lenses and reasonable distribution of focal powers, the optical system has good performances of large aperture, small distortion, high pixel, good athermalization and the like.

Description

High-pixel infrared optical system and its applied camera module Technical field:

The invention relates to an optical system and an applied camera module, in particular to a high-pixel infrared optical system and an applied camera module.

Background technique:

With the application of infrared imaging technology and the development of intelligent driving assistance systems, infrared lenses are more and more widely used in the automotive field. However, the traditional infrared lens has the problem of a large number of lenses and a complicated structure.

Summary of the invention:

In order to overcome the problems of a large number of lenses and high cost of traditional infrared lenses, an embodiment of the present invention provides a high-pixel infrared optical system.

A high-pixel infrared optical system, which includes a first lens, a second lens, a third lens, and a fourth lens in order from the object surface to the image surface along the optical axis;

The object surface side of the first lens is a convex surface, and the image surface side is a concave surface, and its refractive power is negative;

The object surface side of the second lens is a convex surface, and the image surface side is a concave surface, and its refractive power is positive;

The object surface side of the third lens is concave, the image surface side is convex, and its refractive power is positive;

The object surface side of the fourth lens is convex, and the image surface side is concave.

On the other hand, the embodiment of the present invention also provides a camera module.

A camera module includes at least an optical lens, and the above-mentioned high-pixel infrared optical system is installed in the optical lens.

The optical system and camera module of the embodiment of the present invention are mainly composed of 4 lenses, the number of lenses is small, and the structure is simple; different lenses are combined with each other and the optical power is reasonably distributed, with large aperture, small distortion, high pixels, and very Good optical properties such as good heat dissipation.

Description of the drawings:

In order to explain the technical solutions in the embodiments of the present invention more clearly, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained from these drawings without creative work.

Fig. 1 is a first structural diagram of the optical system or camera module of the present invention;

Figure 2 is a distortion curve diagram of the optical system or camera module of the present invention at +25°C;

Fig. 3 is a graph of the MTF curve at +25°C of the optical system or camera module of the present invention;

Fig. 4 is a relative illuminance diagram of the optical system or camera module of the present invention at +25°C;

Figure 5 is a graph of the MTF curve at -40°C of the optical system or camera module of the present invention;

Fig. 6 is a graph of the MTF curve at +85°C of the optical system or camera module of the present invention;

FIG. 7 is a second structural diagram of the optical system or camera module of the present invention;

Detailed ways:

In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

When the embodiments of the present invention refer to ordinal numbers such as "first" and "second", unless they actually express the meaning of the order according to the context, they should be understood as only for distinguishing purposes.

In the description of the present invention, it should be noted that the terms "installed", "connected", and "connected" should be understood in a broad sense unless otherwise clearly specified and limited. For example, they can be fixed or detachable. Connected or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in the present invention can be understood in specific situations.

The embodiment of the present invention provides a high-pixel infrared optical system, which includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 in order from the object plane to the image plane along the optical axis.

The object surface side of the first lens 1 is a convex surface, and the image surface side is a concave surface, and its refractive power is negative;

The object surface side of the second lens 2 is a convex surface, and the image surface side is a concave surface, and its refractive power is positive;

The object surface side of the third lens 3 is a concave surface, and the image surface side is a convex surface, and its refractive power is positive;

The object surface side of the fourth lens 4 is a convex surface, and the image surface side is a concave surface, and its refractive power can be positive or negative.

The optical system of the embodiment of the present invention is mainly composed of 4 lenses, the number of lenses is small, and the structure is simple; different lenses are combined with each other and the optical power is reasonably distributed, with large aperture, small distortion, high pixels, and very good heat dissipation Poor performance.

Exemplarily, as a specific implementation of this solution without limitation, as shown in FIG. 1, the object surface side of the first lens 1 in this embodiment is a convex surface, the image surface side is a concave surface, and its refractive power is negative; The object surface side of the second lens 2 is a convex surface, and the image surface side is a concave surface, and its refractive power is positive; the object surface side of the third lens 3 is a concave surface, and the image surface side is a convex surface, and its refractive power is positive; The object surface side of the lens 4 is a convex surface, and the image surface side is a concave surface, and its refractive power is positive.

Exemplarily, as a specific implementation of this solution and not a limitation, as shown in FIG. 7, the object surface side of the first lens 1 in this embodiment is a convex surface, the image surface side is a concave surface, and its refractive power is negative; The object surface side of the second lens 2 is a convex surface, and the image surface side is a concave surface, and its refractive power is positive; the object surface side of the third lens 3 is a concave surface, and the image surface side is a convex surface, and its refractive power is positive; The object surface side of the lens 4 is a convex surface, and the image surface side is a concave surface, and its refractive power is negative.

Further, as a preferred embodiment of this solution and not a limitation, the optical system satisfies: TTL/EFL≤1.79, where TTL is the distance from the vertex of the first lens 1 of the optical system to the imaging surface 6, and EFL is the optical system. The effective focal length of the system. Using different lenses to combine with each other and reasonably distribute the optical power, it has good performance such as large aperture, small distortion, high pixels, and very good athermalization.

Still further, as a preferred embodiment of this solution but not a limitation, the first lens and the second lens are cemented with each other to form a combined lens. The structure is simple and compact, and the combination of different lenses and the reasonable distribution of optical power can ensure good optical performance.

Still further, as a preferred embodiment of this solution but not a limitation, each lens of the optical system satisfies the following conditions:

(1)-10<f1<-3;

(2) 2<f2<5;

(3) 3<f3<10;

(4)-270<f4<100;

Among them, f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, and f4 is the focal length of the fourth lens 4. Through the mutual combination of different lenses and the reasonable distribution of optical power, the optical system has good performance such as large aperture, small distortion, high pixels, and very good athermalization.

Furthermore, as a preferred embodiment of this solution but not a limitation, each lens of the optical system satisfies the following conditions:

(1)-3.0<f1/f<-1.0;

(2) 0.5<f2/f<3.0;

(3) 0.5<f3/f<3.0;

(4) -50.0<f4/f<20.0;

Where, f is the focal length of the entire optical system, f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, and f4 is the focal length of the fourth lens 4. Through the mutual combination of different lenses and the reasonable distribution of optical power, the optical system has good performance such as large aperture, small distortion, high pixels, and very good athermalization.

Still further, as a preferred embodiment of this solution but not a limitation, the material refractive index Nd1 of the first lens 1 and the material Abbe constant Vd1 satisfy: 1.40<Nd1<1.70, 50<Vd1<90. The structure is simple, and good optical performance can be guaranteed.

Furthermore, as a preferred embodiment of the present solution but not a limitation, the material refractive index Nd2 of the second lens 2 and the material Abbe's constant Vd2 satisfy: 1.85<Nd2<2.05, 20<Vd2<40. The structure is simple, and good optical performance can be guaranteed.

Furthermore, as a preferred embodiment of this solution but not a limitation, the material refractive index Nd3 and the material Abbe constant Vd3 of the third lens 3 satisfy: 1.50<Nd3<1.70, 20<Vd3<40. The structure is simple, and good optical performance can be guaranteed.

Still further, as a preferred embodiment of this solution but not a limitation, the material refractive index Nd4 and the material Abbe constant Vd4 of the fourth lens 4 satisfy: 1.50<Nd4<1.70, 20<Vd4<40. The structure is simple, and good optical performance can be guaranteed.

Furthermore, as a specific implementation of this solution without limitation, the diaphragm 5 of the optical system is located between the second lens 2 and the third lens 3. For adjusting the intensity of the light beam, preferably, the diaphragm 5 is arranged on the second lens 2 close to the object side. In this embodiment, the positions of the lenses and the diaphragm are fixed.

Still further, as a preferred embodiment of this solution but not a limitation, the third lens 3 and the fourth lens 4 are plastic aspheric lenses. It can effectively eliminate the impact of spherical aberration on the lens performance, improve the resolution of the optical lens, effectively achieve athermalization, and reduce the processing difficulty and production cost of the lens.

Furthermore, as a preferred embodiment of this solution but not a limitation, a band-pass filter is provided between the fourth lens 4 and the image plane 6. It can filter the visible light in the environment to avoid visible light interference.

Specifically, with reference to Fig. 1, in this embodiment, the focal length of the first lens 1 is f1=-7.938mm, the focal length of the second lens 2 is f2=3.562mm, the focal length of the third lens 3 is f3=8.168mm, and the fourth lens The focal length of 4 is f4=67.417mm. In this embodiment, along the optical axis direction, the thickness value D2 from the object surface vertex of the first lens 1 to its image surface vertex, the thickness value D2 from the object surface vertex of the second lens 2 to its image surface vertex, and the first lens 2 The distance D3 from the vertex on the image side of the second lens 2 to the vertex on the object side of the third lens 3 satisfies: D1+D2<D3. The basic parameters of this optical system are shown in the following table:

surface Radius of curvature R(mm) Interval D(mm) Refractive index Nd Dispersion value Vd S1 12.0 0.50 1.5 70 S2 2.5 1.00 1.9 35 S3 17.0 0.15 To To STO INFINITY 1.80 To To S5 -2.0 1.30 1.6 twenty three S6 -1.5 0.10 To To S7 4.5 1.50 1.6 twenty three S8 4.0 2.00 To To S9 INFINITY 0.70 1.5 64 S10 INFINITY 0.30 To To IMA INFINITY 0.00 To To

In the above table, from the object plane to the image plane along the optical axis, S1 and S2 correspond to the two surfaces of the first lens 1; S2 and S3 correspond to the two surfaces of the second lens 2; STO is the position of the diaphragm; S5 , S6 correspond to the two surfaces of the third lens 3; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 correspond to the two surfaces of the bandpass filter; IMA is the image plane 6.

其中，参数c＝1/R，即为半径所对应的曲率，y为径向坐标，其单位和透镜长度单位相同，k为圆锥二次曲线系数，a ₁至a ₆分别为各径向坐标所对应的系数。所述第三透镜3的S5表面和S6表面、第四透镜4的S7表面和S8表面的非球面相关数值如下表所示： More specifically, the surfaces of the third lens 3 and the fourth lens 4 are aspherical, which satisfies the following equation:

Among them, the parameter c=1/R, which is the curvature corresponding to the radius, y is the radial coordinate, and its unit is the same as the lens length unit, k is the conic conic coefficient, and a ₁ to a ₆ are the radial coordinates respectively The corresponding coefficient. The aspherical related values of the S5 surface and S6 surface of the third lens 3, the S7 surface and the S8 surface of the fourth lens 4 are shown in the following table:

To K a ₁ a ₂ a ₃ a ₄ S5 -0.40 0 -0.003409507633833000 -0.016038167970829999 0.012480154401390000 S6 -0.70 0 0.000235028520440300 -0.000038830217112540 0.000330841178015300 S7 0.20 0 -0.022305296602539999 0.005448659620065000 -0.000838933906264700 S8 0.80 0 -0.040782844476839997 0.006602358763897000 -0.000803390991681700

It can be seen from FIGS. 2 to 6 that the optical system in this embodiment has good optical performance such as high resolution and very good athermalization performance.

A camera module includes at least an optical lens, and the high-pixel infrared optical system described above is installed in the optical lens.

The optical system and camera module of the embodiment of the present invention are mainly composed of 4 lenses, the number of lenses is small, the structure is simple; different lenses are combined with each other and the optical power is reasonably distributed, with large aperture, small distortion, high pixels, and very Good performance such as good heat dissipation.

The above is one or more implementation manners provided in combination with specific content, and it is not deemed that the specific implementation of the present invention is limited to these descriptions. Any similarity or similarity with the method and structure of the present invention, or several technical deductions or substitutions made under the premise of the concept of the present invention, should be regarded as the protection scope of the present invention.

Claims (10)

A high-pixel infrared optical system, which includes a first lens, a second lens, a third lens, and a fourth lens in order from the object surface to the image surface along the optical axis; and is characterized in that, The object surface side of the first lens is a convex surface, and the image surface side is a concave surface, and its refractive power is negative; The object surface side of the second lens is a convex surface, and the image surface side is a concave surface, and its refractive power is positive; The object surface side of the third lens is concave, the image surface side is convex, and its refractive power is positive; The object surface side of the fourth lens is convex, and the image surface side is concave. The high-pixel infrared optical system of claim 1, wherein the optical system satisfies: TTL/EFL≤1.79, where TTL is the distance from the vertex of the first lens of the optical system to the imaging surface, and EFL is The effective focal length of the optical system. The high-pixel infrared optical system of claim 1, wherein the first lens and the second lens are cemented with each other to form a combined lens. The high-pixel infrared optical system of claim 1, wherein the diaphragm of the optical system is located between the second lens and the third lens, and is close to the second lens side. The high-pixel wide-angle infrared optical system of claim 1, 2, 3, or 4, wherein each lens of the optical system satisfies the following conditions: (1)-10<f1<-3; (2) 2<f2<5; (3) 3<f3<10; (4)-270<f4<100; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f4 is the focal length of the fourth lens; and/or Each lens of the optical system satisfies the following conditions: (1)-3.0<f1/f<-1.0; (2) 0.5<f2/f<3.0; (3) 0.5<f3/f<3.0; (4) -50.0<f4/f<20; Among them, f is the focal length of the entire optical system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f4 is the focal length of the fourth lens. The high-pixel infrared optical system of claim 1, 2, 3 or 4, wherein the refractive index Nd1 of the material of the first lens and the Abbe constant Vd1 of the material satisfy: 1.40<Nd1<1.70, 50<Vd1<90 . The high-pixel wide-angle infrared optical system according to claim 1, 2, 3 or 4, wherein the material refractive index Nd2 of the second lens and the material Abbe constant Vd2 satisfy: 1.85<Nd2<2.05, 20<Vd2< 40. The high-pixel wide-angle infrared optical system according to claim 1, 2, 3 or 4, wherein the material refractive index Nd3 and the material Abbe constant Vd3 of the third lens satisfy: 1.50<Nd3<1.70, 20<Vd3< 40. The high-pixel wide-angle infrared optical system according to claim 1, 2, 3 or 4, wherein the material refractive index Nd4 and the material Abbe constant Vd4 of the fourth lens satisfy: 1.50<Nd4<1.70, 20<Vd4< 40. A camera module comprising at least an optical lens, wherein the high-pixel infrared optical system according to any one of claims 1-9 is installed in the optical lens.

Images