An optical lens, a camera module and an electronic device

Abstract

The present application discloses an optical lens, which includes, from the object side to the image side along the optical axis, at least: an aperture, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, and a fourth lens with negative refractive power; the effective focal length f of the optical lens and the effective focal length f2 of the second lens satisfy the following relationship: |f / f2| < 0.73. The present application also discloses a camera module and an electronic device.

Description

Technical Field

[0001] This application relates to the field of optical elements, and particularly to an optical lens, a camera module, and an electronic device. Background Art

[0002] With the wide application of electronic devices, the requirements for the imaging function of electronic devices are getting higher and higher; therefore, an optical lens capable of clearly photographing objects at a short distance (such as a distance on the order of millimeters) is needed. Summary of the Invention

[0003] Embodiments of this application provide an optical lens, a camera module, and an electronic device, which can clearly photograph objects at a short distance (such as a distance on the order of millimeters).

[0004] The technical solution of the embodiments of this application is implemented as follows:

[0005] Embodiments of this application provide an optical lens, which includes at least:

[0006] An aperture, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, and a fourth lens with negative refractive power, along the optical axis from the object side to the image side;

[0007] The effective focal length f of the optical lens and the effective focal length f2 of the second lens satisfy the following relationship: |f / f2| < 0.73.

[0008] In the above solution, the entrance pupil diameter EPD of the optical lens and the effective semi-aperture DTg of the aperture at the object side surface of the aperture satisfy the following relationship: EPD / DTg > 1.6.

[0009] In the above solution, the height H1 of the object and the image height H2 of the object after passing through the optical lens satisfy the following relationship: 0.70 < H2 / H1 < 0.85.

[0010] In the above solution, the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens and the effective focal length f of the optical lens satisfy the following relationship: 1.0 < ImgH / f < 1.6.

[0011] In the above solution, the radius of curvature R1 of the object side surface of the first lens and the effective focal length f1 of the first lens satisfy the following relationship: 0.5 < R1 / f1 < 1.3.

[0012] In the above solution, the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, and the distance TTL on the optical axis from the object side surface of the first lens to the imaging surface of the optical lens satisfy the following relationship: 0.5 < (CT1 + CT2) / TTL * 5 < 1.4.

[0013] In the above solution, the entrance pupil diameter EPD of the optical lens and the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens satisfy the following relationship: 0.3 < EPD / ImgH < 0.6.

[0014] In the above solution, the distance TTL on the optical axis from the object side surface of the first lens to the imaging surface of the optical lens and the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens satisfy the following relationship: TTL / ImgH ≤ 1.6.

[0015] In the above solution, along the optical axis from the object side to the image side, after the fourth lens, the optical lens further includes: a fifth lens.

[0016] The embodiment of the present application further provides a camera module, and the camera module includes the above optical lens and an image sensor.

[0017] The embodiment of the present application further provides an electronic device, and the electronic device includes the above optical lens.

[0018] The optical lens, camera module and electronic device provided by the embodiment of the present application include at least: an aperture, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, and a fourth lens with negative refractive power along the optical axis from the object side to the image side; the effective focal length f of the optical lens and the effective focal length f2 of the second lens satisfy the following relationship: |f / f2| < 0.73. Using the optical lens and electronic device provided by the embodiment of the present application, it is possible to clearly photograph an object at a short distance, such as clearly photographing an object with an object distance of 3 millimeters. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of an external attachment optical lens provided for the present application outside an electronic device;

[0020] Figure 2 It is a schematic diagram of an optional structure of the optical lens according to the embodiment of the present application;

[0021] Figure 3 It is another schematic diagram of an optional structure of the optical lens according to the embodiment of the present application;

[0022] Figure 4Schematic diagram of the optical path inside the optical lens when the imaging object distance of the embodiment of the present application is 3 mm;

[0023] Figure 5 Schematic diagram of the optical performance of the optical lens according to an alternative embodiment of the present application Figure 1 ;

[0024] Figure 6 Schematic diagram of the optical performance of the optical lens according to an alternative embodiment of the present application Figure 2 ;

[0025] Figure 7 Schematic diagram of the optical performance of the optical lens according to an alternative embodiment of the present application Figure 3 . Detailed implementation manners

[0026] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] In order to be able to photograph an object with an object distance in the millimeter range, such as when photographing an object with an object distance less than 3 mm, the optical lens inside the electronic device cannot achieve focusing and cannot image an object with an object distance in the millimeter range. However, it can be achieved by setting an external optical lens outside the electronic device and attaching the external optical lens to the surface of the main camera lens of the electronic device, as Figure 1 shown. However, using an external optical lens will increase the volume of the electronic device and is not convenient to use.

[0028] Based on the above problems, the present application provides an optical lens. A schematic diagram of an alternative structure of the optical lens is shown in Figure 2 , and along the optical axis of the optical lens, from the object side to the image side, it at least includes: an aperture 10, a first lens 11 with positive refractive power, a second lens 12 with negative refractive power, a third lens 13 with positive refractive power, and a fourth lens 14 with negative refractive power.

[0029] In some embodiments, the first lens 11 has an object side 1 and an image side 2, and both the object side 1 and the image side 2 are convex surfaces. The second lens 12 has an object side 3 and an image side 4, and the object side 3 is a concave surface. The third lens 13 has an object side 5 and an image side 6, the object side 5 is a concave surface, and the image side 6 is a convex surface. The fourth lens 14 has an object side 7 and an image side 8, the object side 7 is a convex surface, and the image side 8 is a concave surface.

[0030] In some embodiments, the entrance pupil diameter EPD of the optical lens and the effective semi-aperture DTg of the aperture 10 at the object side of the aperture 10 satisfy the following relationship: EPD / DTg > 1.6; for example, EPD / DTg = 2.0.

[0031] In some embodiments, the effective focal length f of the optical lens and the effective focal length f2 of the second lens satisfy the following relationship: |f / f2| < 0.73; for example, f / f2 = -0.5, or f / f2 = 0.4.

[0032] In some embodiments, the height H1 of the object and the image height H2 of the object after passing through the optical lens satisfy the following relationship: 0.70 < H2 / H1 < 0.85; that is, the magnification ratio of the image formed by the object after passing through the optical lens is 0.70 to 0.85 times. In specific implementation, the magnification ratio can be calculated by calculating the ratio of the height of the image to the height of the object.

[0033] In some embodiments, the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens and the effective focal length f of the optical lens satisfy the following relationship: 1.0 < ImgH / f < 1.6; for example, ImgH / f = 1.3.

[0034] In some embodiments, the radius of curvature R1 of the object side 1 of the first lens 11 and the effective focal length f1 of the first lens 11 satisfy the following relationship: 0.5R1 / f1 1.3; for example, R1 / f1 = 0.8.

[0035] In some embodiments, the central thickness CT1 of the first lens 11 on the optical axis, the central thickness CT2 of the second lens on the optical axis, and the distance TTL on the optical axis from the object side of the first lens to the imaging surface of the optical lens satisfy the following relationship:

[0036] 0.5 < (CT1 + CT2) / TTL * 5 < 1.4.

[0037] In some embodiments, the entrance pupil diameter EPD of the optical lens and the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens satisfy the following relationship: 0.3 < EPD / ImgH < 0.6.

[0038] In some embodiments, the distance TTL on the optical axis from the object side of the first lens 11 to the imaging surface of the optical lens and the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens satisfy the following relationship: TTL / ImgH ≤ 1.6.

[0039] In some embodiments, another optional structural schematic diagram of the optical lens, such as Figure 3As shown, in addition to including the above-mentioned components, along the optical axis from the object side to the image side, after the fourth lens 14, the optical lens further includes: a fifth lens 15. The fifth lens 15 has an object side surface 9 and an image side surface 10; the fifth lens 15 can be a filter, or the fifth lens can be a glass sheet.

[0040] In the embodiments of the present application, the basic parameter table of the optical lens is shown in Table 1 below:

[0041]

[0042]

[0043] Table 1

[0044] Among them, the radius of curvature in Table 1 refers to the radius of curvature at the intersection of the optical axis and the object side surface or the image side surface. The distance -0.043mm in Table 1 refers to the distance between the vertex of the object side surface 1 of the first lens 11 and the aperture 10 on the optical axis. The distance 0.579mm in Table 1 refers to the distance between the vertex of the object side surface 1 and the vertex of the image side surface 2 of the first lens 11. The distance 0.018mm in Table 1 refers to the distance between the vertex of the image side surface 2 of the first lens 11 and the vertex of the object side surface 3 of the second lens 12 on the optical axis. And so on, the distance 0.210mm in Table 1 refers to the distance between the vertex of the object side surface 3 and the vertex of the image side surface 4 of the second lens 12 on the optical axis. The 0.241 in Table 1 refers to the distance between the vertex of the image side surface 4 of the second lens 12 and the vertex of the object side surface 5 of the third lens 13 on the optical axis. The distance 0.934mm in Table 1 refers to the distance between the vertex of the object side surface 5 and the vertex of the image side surface 6 of the third lens 13 on the optical axis. The distance 0.020mm in Table 1 refers to the distance between the vertex of the image side surface 6 of the third lens 13 and the vertex of the object side surface 7 of the fourth lens 14 on the optical axis. The distance 0.407mm in Table 1 refers to the distance between the vertex of the object side surface 7 and the vertex of the image side surface 8 of the fourth lens 14 on the optical axis. The distance 0.666mm in Table 1 refers to the distance between the vertex of the image side surface 8 of the fourth lens 14 and the vertex of the object side surface 9 of the fifth lens 15 on the optical axis. The 0.210 in Table 1 refers to the distance between the vertex of the object side surface 9 and the vertex of the image side surface 10 of the fifth lens 15 on the optical axis. The distance 0.285mm in Table 1 refers to the distance between the vertex of the image side surface 10 of the fifth lens 15 and the object imaging on the optical axis.

[0045] In some embodiments of the present application, the object side surfaces and the image side surfaces of the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 are all aspherical surfaces, and the surface profiles of the aspherical surfaces satisfy the following formula:

[0046]

[0047] Among them, z is the depth of the aspheric surface, that is, the distance between the point on the aspheric surface with a distance of Y from the optical axis and the tangent plane perpendicular to the optical axis and passing through the vertex of the aspheric surface; c = 1 / r, where r is the surface curvature radius, h is the distance between the point on the aspheric surface and the optical axis, k is the conic coefficient, A is the fourth-order coefficient, B is the sixth-order coefficient, C is the eighth-order coefficient, D is the tenth-order coefficient, E is the twelfth-order coefficient, F is the fourteenth-order coefficient, and G is the sixteenth-order coefficient. The parameters of each aspheric surface are shown in Table 2 below:

[0048]

[0049] Table 2

[0050] Based on Figure 2 Table 1 and Table 2, the effective focal length f of an optical lens is 1.335 mm. The distance TTL on the optical axis from the object side of the first lens to the imaging surface of the optical lens is 3.57 mm. The maximum image height field of view (Field Of View, FOV) is 77.6 degrees, and the f-number is 2.8.

[0051] The above Table 1 and Table 2 are only examples, and the basic parameters of the optical lens and the parameters of each aspheric surface can be appropriately changed within the scope of the claims of this application.

[0052] In an alternative embodiment of this application, when the imaging object distance of the optical lens is 3 mm, the light path inside the optical lens is as Figure 4 shown. The light passes through the aperture 10, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, and the fifth lens 15 in sequence and then forms an image.

[0053] Schematic diagram of the optical performance of the optical lens in an alternative embodiment of this application Figure 1 , as Figure 5 shown, is a schematic diagram of the resolution of the optical lens, where the resolution is the number of line pairs that the optical lens can resolve per millimeter. According to Figure 5 , it can be known that when the imaging height on the Y-axis is 0.8 mm and the resolution of the optical lens is 110 LP / mm, the MTF is 0.7.

[0054] Schematic diagram of the optical performance of the optical lens in an alternative embodiment of this application Figure 2 , as Figure 6 shown, is a schematic diagram of the lateral chromatic aberration of the image; taking the light with a wavelength of 555 nm as the reference, the lateral chromatic aberration of light with different wavelengths.

[0055] Schematic diagram of the optical performance of the optical lens in an alternative embodiment of this application Figure 3 , as Figure 7As shown, it is a schematic diagram of the distortion curve of imaging. The optical lens provided by the embodiments of the present application is located inside the camera module. By using the optical lens provided by the embodiments of the present application or the camera module including the optical lens provided by the embodiments of the present application, objects at close range can be clearly photographed, such as objects with an object distance in the millimeter range; specifically, an object with an object distance of 3 mm can be clearly photographed; and, according to Figure 5 , Figure 6 and Figure 7 shown in the schematic diagram of optical performance, the optical lens provided by the embodiments of the present application can achieve good imaging quality.

[0056] The camera module provided by the embodiments of the present application may further include an image sensor in addition to the optical lens provided by the embodiments of the present application.

[0057] The embodiments of the present application also provide an electronic device including the optical lens provided by the above embodiments of the present application.

[0058] It should be noted that in the embodiments of the present application, the expressions such as first, second, and third are only used to distinguish one feature from another feature, or to distinguish different elements in the same type of elements, and do not represent any limitation on the features or elements. Therefore, without departing from the teachings of the present application, the first lens in the embodiments of the present application may also be referred to as the seventh lens, the eighth lens, etc.

[0059] For the convenience of description and explanation of the present application, the sizes, thicknesses, and shapes of each lens may be exaggerated. That is, the spherical or aspherical shapes shown in the drawings are given by way of example. Therefore, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes described in the drawings; the drawings are only examples and are not drawn strictly to scale.

[0060] In the embodiments of the present application, when the terms "include", "include with", "have", "contain", and "contain with" are used in the specification of the present application, it means that the stated features, elements, and components exist, but do not exclude the existence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when the term "at least include" is used in the specification of the present application, it means that in addition to the at least included features or elements stated, other features or elements may also be included.

[0061] In the embodiments of the present application, the surface of each lens closest to the object to be photographed is called the object side of the lens, and the surface of each lens closest to the imaging surface is called the image side of the lens.

[0062] As described above, it is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claimed rights.

Claims

1. An optical lens, characterized in that, From the object side to the image side along the optical axis, it includes: An aperture, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, and a fourth lens with negative refractive power; The effective focal length f of the optical lens and the effective focal length f2 of the second lens satisfy the following relationship: |f / f2| < 0.73; The height H1 of the object and the image height H2 of the object after passing through the optical lens satisfy the following relationship: 0.70 < H2 / H1 < 0.85; The number of lenses with refractive power in the optical lens is four.

2. The optical lens according to claim 1, wherein The entrance pupil diameter EPD of the optical lens and the effective semi-aperture DTg of the aperture at the object side surface of the aperture satisfy the following relationship: EPD / DTg > 1.

6.

3. The optical lens according to claim 1, wherein The semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens and the effective focal length f of the optical lens satisfy the following relationship: 1.0 < ImgH / f < 1.

6.

4. The optical lens according to claim 1, wherein The radius of curvature R1 of the object side surface of the first lens and the effective focal length f1 of the first lens satisfy the following relationship: 0.5 < R1 / f1 < 1.

3.

5. The optical lens according to claim 1, characterized in that, The central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, and the distance TTL on the optical axis from the object side surface of the first lens to the imaging surface of the optical lens satisfy the following relationship: 0.5 < (CT1 + CT2) / TTL * 5 < 1.

4.

6. The optical lens according to claim 1, wherein, The entrance pupil diameter EPD of the optical lens and the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens satisfy the following relationship: 0.3 < EPD / ImgH < 0.

6.

7. The optical lens according to claim 1, wherein The distance TTL on the optical axis from the object side surface of the first lens to the imaging surface of the optical lens and the semi-diagonal length ImgH of the effective pixel region on the imaging surface of the optical lens satisfy the following relationship: TTL / ImgH ≤ 1.

6.

8. A camera module, characterized in that, The camera module includes an optical lens and an image sensor, and the optical lens is the optical lens according to any one of claims 1 to 7.

9. An electronic device, characterized in that, The electronic device includes the optical lens according to any one of claims 1 to 7.

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