A visible and infrared confocal lens

Abstract

The utility model discloses a visible light and infrared confocal lens belongs to camera lens technical field. A visible light and infrared confocal lens, including first lens, second lens, third lens, fourth lens and fifth lens, the object side and the image side of first lens, second lens, third lens, fourth lens and fifth lens are all aspherical surface, still include the diaphragm of setting in first lens front, first lens, third lens and fourth lens all have positive refractive power, the utility model discloses a five lens formula design that adopts first lens, second lens, third lens, fourth lens, fifth lens and diaphragm, and the best range of the surface shape structure and optical parameter of each lens is combined, makes the focus of visible light and infrared light confocal, ensures that the lens can high imaging quality and low distortion in day and night, meets the development trend of the present electronic product with good function and day and night confocal.

Description

Technical Field

[0001] This utility model relates to the field of camera lens technology, and in particular to a visible light and infrared confocal lens. Background Technology

[0002] With the development of technology, people have higher and higher requirements for vehicle cameras, facial recognition, and security cameras. The imaging requirements for cameras are also higher. The lenses need to have high transmittance, high resolution and low distortion for visible light, and also need to have high resolution and low distortion for infrared imaging at night to ensure image clarity and recognition accuracy.

[0003] However, traditional lenses have poorly optimized surface structure and optical parameters of each lens, making it difficult to achieve better co-focusing of visible and infrared light. This results in poor image quality and resolution, which is difficult to meet the current trend of electronic products that require high functionality and co-focusing day and night. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing lenses, which make it difficult to achieve co-focusing of visible and infrared light, affecting image quality and resolution, and failing to meet the requirement of day and night co-focusing. Therefore, this invention proposes a lens that allows for co-focusing of visible and infrared light.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A confocal lens for visible light and infrared light includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The object-side and image-side surfaces of the first, second, third, fourth, and fifth lenses are aspherical. The lens also includes an aperture stop disposed in front of the first lens. The first, third, and fourth lenses all have positive refractive power, while the second and fifth lenses all have negative refractive power. The object-side surface of the first lens is convex at its paraxial position. The object-side surfaces of the second and fifth lenses are both convex, and the image-side surfaces of the third and fourth lenses are both convex. (2.03 < f / R4 < 2.18, 1.32) <TTL / EFL<1.68。

[0006] In a preferred embodiment of this utility model, 0.08 < (R2 + R3) / (R2 - R3) < 0.23.

[0007] In a preferred embodiment of this utility model, 0.43 < ∑CT / TTL < 0.52.

[0008] As a preferred embodiment of this utility model, 0.8 <ct1 / ct2<1.30。

[0009] As a preferred embodiment of this utility model, 1.2 <TTL / f<1.56。

[0010] As a preferred embodiment of this utility model, 1.43 <TL / Dg<1.97。

[0011] As a preferred embodiment of this utility model, 25.3 <f23 / f4<31.2。

[0012] As a preferred embodiment of this utility model, 1.65 <f2 / R3<1.95。

[0013] As a preferred embodiment of this utility model, 4.12 <f3 / R5<4.68。

[0014] Compared with the prior art, this utility model provides a visible light and infrared confocal lens, which has the following beneficial effects: 1. This visible light and infrared confocal lens employs a five-lens design consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and an aperture stop. The optimal range of surface structure and optical parameters of each lens is combined with optimization of aspherical coefficient, radius of curvature, and air gap. This allows visible light and infrared light to be confocal, resulting in good image quality and high resolution due to high pixel count. It ensures high image quality and low distortion both day and night, aligning with the current trend in electronic products that prioritize functionality and day / night confocal focus.

[0015] The parts not covered in this device are the same as or can be implemented using existing technologies. This utility model solves the problem that existing lenses are not optimized enough, making it difficult to achieve co-focus of visible light and infrared light, which affects image quality and resolution and does not meet the requirements of day and night co-focus. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the planar structure of a visible light and infrared confocal lens proposed in this utility model; Figure 2 This invention proposes a distortion correction method for a confocal lens that integrates visible light and infrared light. Figure One ; Figure 3 This invention proposes an axial chromatic aberration curve for a confocal lens for visible light and infrared. Figure One ; Figure 4 This invention proposes a distortion correction method for a confocal lens that integrates visible light and infrared light. Figure Two ; Figure 5 This invention proposes an axial chromatic aberration curve for a confocal lens for visible light and infrared. Figure Two ; Figure 6 This invention proposes a distortion correction method for a confocal lens that integrates visible light and infrared light.Figure Three ; Figure 7 This invention proposes an axial chromatic aberration curve for a confocal lens for visible light and infrared. Figure Three ; Figure 8 This invention proposes a distortion correction method for a confocal lens that integrates visible light and infrared light. Figure Four ; Figure 9 This invention proposes an axial chromatic aberration curve for a confocal lens for visible light and infrared. Figure Four ; Figure 10 This invention proposes a distortion correction method for a confocal lens that integrates visible light and infrared light. Figure Five ; Figure 11 This invention proposes an axial chromatic aberration curve for a confocal lens for visible light and infrared. Figure Five .

[0017] In the diagram: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Aperture stop. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0019] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] Example 1: Reference Figure 1This utility model provides a visible light and infrared confocal lens, including a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 5. The object-side and image-side surfaces of the first lens 1, second lens 2, third lens 3, fourth lens 4, and fifth lens 5 are all aspherical. It also includes an aperture stop 6 disposed in front of the first lens 1, used to control the amount of light passing through the lens. The first lens 1, third lens 3, and fourth lens 4 all have positive refractive power, while the second lens 2 and fifth lens 5 have negative refractive power. These positive and negative refractive powers cause the incident light to diffuse outward, expanding the field of view and reducing distortion, thereby optimizing the optical performance of the entire system. The object-side surface of the first lens 1 is convex at the paraxial position, the object-side surfaces of the second lens 2 and fifth lens 5 are both convex, and the image-side surfaces of the third lens 3 and fourth lens 4 are both convex. In some embodiments, the ratio of the overall focal length of the lens group to the radius of curvature of the image-side surface of the second lens 2 satisfies the following range: 2.03 < f / R4 < 2.18; In some embodiments, the ratio of the total optical length of the camera lens to the focal length of the lens group satisfies the following range: 1.32 <TTL / EFL<1.68。

[0021] The optimal parameter range for the lens can be obtained using the above ratios. Specifically, in use, a five-lens design consisting of a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and an aperture stop 6 is adopted. The surface structure of each lens is combined with the optimal range of optical parameters. Through the optimization of aspherical coefficient, radius of curvature, and air gap, the focal point of visible light and infrared light is confocal, resulting in good image quality and high resolution due to high pixel count. This ensures that the lens can achieve high image quality and low distortion day and night, which is in line with the current development trend of electronic products that are functional and have confocal day and night.

[0022] In some embodiments, the ratio of the radius of curvature of the object side surface of the second lens 2 plus the radius of curvature of the image side surface of the third lens 3 to the radius of curvature of the object side surface of the second lens 2 minus the radius of curvature of the image side surface of the third lens 3 satisfies the following range: 0.08 < (R2 + R3) / (R2 - R3) < 0.23.

[0023] In some embodiments, the ratio of the sum of the center thicknesses of the first lens 1 to the fifth lens 5 along the optical axis to the total optical length of the imaging optical lens satisfies the following range: 0.43 < ∑CT / TTL < 0.52.

[0024] In some embodiments, the ratio of the center thickness of the first lens 1 to the center thickness of the second lens 2 satisfies the following range: 0.8 <ct1 / ct2<1.30。

[0025] In some embodiments, the ratio of the total optical length of the camera lens to the overall focal length of the lens group satisfies the following range: 1.2 <TTL / f<1.56。

[0026] In some embodiments, the ratio of the distance between the object-side vertex of the first lens 1 and the imaging plane to the diagonal length of the image plane at the maximum usable viewing angle of the lens group satisfies the following range: 1.43 <TL / Dg<1.97。

[0027] In some embodiments, the ratio of the focal length of the combination of the second lens 2 and the third lens 3 to the focal length of the fourth lens 4 satisfies the following range: 25.3 <f23 / f4<31.2。

[0028] In some embodiments, the ratio of the focal length of the second lens 2 to the radius of curvature of the image-side surface of the third lens 3 satisfies the following range: 1.65 <f2 / R3<1.95。

[0029] In some embodiments, the ratio of the focal length of the third lens 3 to the radius of curvature of the image-side surface of the fifth lens 5 satisfies the following range: 4.12 <f3 / R5<4.68。

[0030] The optimal parameter range for the lens can be obtained by using the above ratios.

[0031] The meanings of "alphanumeric" in this utility model are as follows: f: The overall focal length of the lens group; R4: Radius of curvature of the image side of the second lens 2; V2: Dispersion coefficient of the second lens 2; V3: Dispersion coefficient of the third lens 3; R2: The radius of curvature of the object-side surface of the second lens 2; R3: Radius of curvature of the side surface of the third lens 3; TTL: Total optical length of a camera lens; ∑CT: The sum of the center thicknesses of the first lens 1 to the fifth lens 5 on the optical axis; CT1: Center thickness of the first lens 1; CT2: Center thickness of the second lens 2; TL: Distance between the object-side vertex of the first lens 1 and the imaging plane; Dg: The diagonal length of the image formed on the image plane at the maximum usable viewing angle of the lens group; f23: The focal length of the combination of the second lens 2 and the third lens 3; f2: Focal length of the second lens 2; f3: Focal length of the third lens 3; f4: Focal length of the fourth lens 4; R5: Radius of curvature of the side surface of the fifth lens 5; EFL: Focal length of the lens assembly.

[0032] Example 2: Based on Example 1, specific parameters were selected as f=4.90mm, Fno=2.11, FOV=71.84°, and the aspheric coefficient was used to obtain the following table:

[0033]

[0034] Specifically, the data in the table above can be used to generate... Figure 2 and Figure 3 .

[0035] Example 3: Based on Example 1, specific parameters were selected as f=4.83mm, Fno=2.12, FOV=72.03°, and the aspheric coefficient was used to obtain the following table:

[0036]

[0037] Specifically, the data in the table above can be used to generate... Figure 4 and Figure 5 .

[0038] Example 4: Based on Example 1, specific parameters were selected as f=4.84mm, Fno=2.10, FOV=72.06°, and the aspheric coefficient was used to obtain the following table:

[0039]

[0040] Specifically, the data in the table above can be used to generate... Figure 6 and Figure 7 .

[0041] Example 5: Based on Example 1, specific parameters were selected as f=4.86mm, Fno=2.11, FOV=71.91°, and the aspheric coefficient, resulting in the following table:

[0042]

[0043] Specifically, the data in the table above can be used to generate... Figure 8 and Figure 9 .

[0044] Example 6: Based on Example 1, specific parameters were selected as f=4.87mm, Fno=2.11, FOV=71.781°, and the aspheric coefficient, resulting in the following table:

[0045]

[0046] Specifically, the data in the table above can be used to generate... Figure 10 and Figure 11 .

[0047] In the table above: f represents focal length, Fno represents aperture number, and FOV represents field of view. These three parameters work together in the design of a visible light and infrared confocal lens to ensure high image quality and low distortion both day and night.

[0048] This utility model is achieved through... Figure 2 , Figure 4 , Figure 6 , Figure 8 , Figure 10 By comparing the changes in the distortion curves, we can see that the lens performs well at different focal lengths, and the amount of deformation of the object after it is imaged through the lens. The closer the distortion curve is to 0, the closer the shape of the image is to the shape of the object. And, through Figure 3 , Figure 5 , Figure 7 , Figure 9 , Figure 11 The comparison of the changes in the central axis chromatic aberration curves shows that each curve represents the focal point of light of different wavelengths after passing through the lens, and the closer the different curves are, the better the lens's chromatic aberration effect.

[0049] This visible light and infrared confocal lens employs a five-lens design consisting of a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and an aperture 6. The optimal range of surface structure and optical parameters for each lens is combined with optimization of aspherical coefficient, radius of curvature, and air gap. This allows for confocal focusing of visible light and infrared light, resulting in superior image quality and high resolution due to high pixel count. The lens ensures high image quality and low distortion both day and night, aligning with the current trend in electronic products that prioritize functionality and day / night confocal focusing.

[0050] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A confocal lens for visible light and infrared, comprising a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), and a fifth lens (5), characterized in that, The object-side surface and image-side surface of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4) and the fifth lens (5) are both aspherical, and an aperture stop (6) is also provided in front of the first lens (1). Among them, the first lens (1), the third lens (3), and the fourth lens (4) all have positive refractive power, the second lens (2) and the fifth lens (5) all have negative refractive power, the object-side surface of the first lens (1) is convex at the paraxial position, the object-side surfaces of the second lens (2) and the fifth lens (5) are both convex, and the image-side surfaces of the third lens (3) and the fourth lens (4) are both convex. 2.03 < f / R4 < 2.18, 1.32 <TTL / EFL<1.68。 2. The visible light and infrared confocal lens according to claim 1, characterized in that, 0.08 < (R2 + R3) / (R2 - R3) < 0.

23.

3. A visible light and infrared confocal lens according to claim 1, characterized in that, 0.43 < ∑CT / TTL < 0.

52.

4. A visible light and infrared confocal lens according to claim 1, characterized in that, The 0.8 <ct1 / ct2<1.30。 5. A visible light and infrared confocal lens according to claim 1, characterized in that, 1.2 <TTL / f<1.56。 6. A visible light and infrared confocal lens according to claim 1, characterized in that, 1.43 <TL / Dg<1.97。 7. A visible light and infrared confocal lens according to claim 1, characterized in that, 25.3 <f23 / f4<31.2。 8. A visible light and infrared confocal lens according to claim 1, characterized in that, 1.65 <f2 / R3<1.95。 9. A visible light and infrared confocal lens according to claim 1, characterized in that, 4.12 <f3 / R5<4.68。

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