An optical system, a camera module and a terminal device

Abstract

The application discloses an optical system, a camera module and a terminal device. The optical system comprises a first lens, a second lens, a third lens and a fourth lens. The first lens, the second lens, the third lens and the fourth lens are arranged in sequence from the object side to the image side of the optical system. The first lens, the second lens, the third lens and the fourth lens are located on the same optical axis. The optical system satisfies the following relationship: 0.445<=f1 / f<=0.481, wherein f1 is the focal length of the first lens, f is the focal length of the optical system, f1 / f2<0, f3 / f4<0, and |f4 / f3|>1, wherein f1, f2, f3 and f4 are the focal lengths of the first lens, the second lens, the third lens and the fourth lens respectively. Through the technical scheme provided by the application, the optical power of each lens is reasonably distributed, and the effect of reducing the aperture of the optical system is realized under the premise of ensuring a large aperture.

Description

Technical Field

[0001] This application belongs to the field of optoelectronic technology, and in particular relates to an optical system, a camera module and a terminal device. Background Technology

[0002] Telephoto lenses for mobile phones, due to their large focal lengths, typically have an optical length exceeding 8mm and a considerable thickness, making a vertical mounting impossible. To accommodate them, a periscope design is necessary, where the lens lies horizontally, and light from the surrounding environment is diverted through a 45° light-adjusting element before entering the lens and forming an image. However, this design has a drawback: the thickness of the phone body limits the potential for increasing the lens's relative aperture. The relative aperture of a lens equals its diameter divided by its focal length. When the focal length remains constant, increasing the relative aperture only increases the lens diameter, which inevitably leads to an increase in lens thickness, resulting in a thicker phone body. Summary of the Invention

[0003] The embodiments of this application provide an optical system, a camera module, and a terminal device, which achieve the effect of reducing the aperture of the optical system while ensuring a large aperture by reasonably allocating the optical power of each lens.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] According to a first aspect of the embodiments of this application, an optical system is provided, including a first lens, a second lens, a third lens, and a fourth lens, wherein the first lens, the second lens, the third lens, and the fourth lens are arranged sequentially from the object side to the image side of the optical system;

[0006] The first lens, the second lens, the third lens, and the fourth lens are located on the same optical axis;

[0007] The optical system satisfies the following relationship:

[0008] 0.445≤f1 / f≤0.481, where f1 is the focal length of the first lens and f is the focal length of the optical system;

[0009] f1 / f2<0, f3 / f4<0, |f4 / f3|>1, where f1, f2, f3 and f4 are the focal lengths of the first lens, the second lens, the third lens and the fourth lens, respectively.

[0010] In some embodiments, the optical system satisfies the following relationship:

[0011] 23.7≤|V2-V1|≤31, 26.8≤|V4-V3|≤38.2, where V1, V2, V3 and V4 are the Abbe numbers of the first lens, the second lens, the third lens and the fourth lens, respectively.

[0012] In some embodiments, the optical system satisfies the following relationship:

[0013] 184.8≤BFL*FOV≤231.77, where BFL is the back focal length of the optical system and FOV is the field of view of the optical system.

[0014] In some embodiments, a filter and an aperture stop are further included, the aperture stop being located on the incident surface side of the first lens, and the filter being located on the exit surface side of the fourth lens, the filter satisfying the following relationship:

[0015] 0.134≤dIR / n5≤0.138, where dIR represents the thickness of the filter and n5 represents the refractive index of the filter.

[0016] In some embodiments, the optical system satisfies the following relationship:

[0017] 0.9641≤n2 / n3≤0.9878, where n2 represents the refractive index of the second lens and n3 represents the refractive index of the third lens.

[0018] In some embodiments, the optical system satisfies the following relationship:

[0019] |R4-R5| / d5*FOV>100, where R4 represents the radius of curvature of the second surface of the second lens, R5 represents the radius of curvature of the first surface of the third lens, d5 represents the interval between the second lens and the third lens, and FOV represents the field of view of the optical system.

[0020] In some embodiments, the optical system satisfies the following relationship:

[0021] 0.63≤(|R1|-|R2|) / (|R1|+|R2|)≤0.7865, where R1 represents the radius of curvature of the first surface of the first lens and R2 represents the radius of curvature of the second surface of the first lens.

[0022] In some embodiments, the optical system satisfies the following relationship:

[0023] 0.418≤BFL / TTL≤0.514, where BFL represents the back focal length of the optical system and TTL represents the total length of the optical system.

[0024] According to a second aspect of the embodiments of this application, a camera module is provided, comprising:

[0025] The optical system described in any of the above items;

[0026] First dimming element;

[0027] Imaging chip;

[0028] Externally incident light enters the optical system through the first dimming element, and after exiting the optical system, it enters the imaging chip for imaging.

[0029] In some embodiments, the imaging surface of the imaging chip is arranged parallel to the optical axis of the optical system, and further includes:

[0030] The second dimming element is located in the light transmission path between the optical system and the imaging chip. The light emitted from the optical system is deflected by the second dimming element to the imaging chip for imaging.

[0031] In some embodiments, the second dimming element includes an incident light surface, an emitting light surface, a reflective surface, a first connecting surface, and a second connecting surface, wherein the first connecting surface is connected between the reflective surface and the incident light surface, and the second connecting surface is connected between the reflective surface and the emitting light surface.

[0032] In some embodiments, the image chip is further comprising: an optical focusing and image stabilization motor, wherein the image chip is disposed on the optical focusing and image stabilization motor;

[0033] The optical focusing and image stabilization motor is used to drive the imaging chip to move along the optical axis of the imaging chip to achieve focusing, and to drive the imaging chip to move in a direction parallel to the imaging surface of the imaging chip to achieve image stabilization.

[0034] In some embodiments, the device further includes: an optical focusing motor and an optical image stabilization motor, wherein the imaging chip is disposed on the optical focusing motor and the first dimming element is disposed on the optical image stabilization motor;

[0035] The optical focusing motor is used to drive the imaging chip to move along the optical axis of the imaging chip to achieve focusing, and the optical image stabilization motor is used to drive the first dimming element to move in a direction parallel to the imaging surface of the imaging chip to achieve image stabilization.

[0036] In some embodiments, the device further includes an optical focusing motor and an optical image stabilization motor, wherein the imaging chip and the second dimming element are assembled together and disposed on the optical focusing motor, and the first dimming element is disposed on the optical image stabilization motor.

[0037] The optical focusing motor is used to drive the second dimming element and the imaging chip together to move along the optical axis of the optical system to achieve focusing, and the optical image stabilization motor is used to drive the first dimming element to move in a direction parallel to the imaging surface of the imaging chip to achieve image stabilization.

[0038] According to a third aspect of the embodiments of this application, a terminal device is provided, including: the camera module described above.

[0039] In some embodiments, the terminal device further includes:

[0040] A housing, wherein a first receiving cavity is provided on the inner side of the housing;

[0041] Camera protective cover;

[0042] The camera protective cover protrudes from the outside of the housing, forming a second receiving cavity that communicates with the first receiving cavity. The optical system is located within the second receiving cavity, and the optical axis of the optical system is perpendicular to the thickness direction of the camera protective cover.

[0043] In this application, the optical system according to the above-described embodiments of the present invention, by rationally allocating the optical power, focal length and other parameters of each lens through the above-described relationship, can ensure a large aperture of F no < 2.5, achieving a greater amount of light transmission and increasing the amount of information captured by the lens. It has the characteristics of a wide imaging range and high imaging quality. That is, under the premise that the optical system has a large aperture, it can also achieve a ratio of NA (entrance pupil diameter) to waist lens diameter D greater than 0.95, that is, while achieving a large aperture, it also makes the local diameter of the lens smaller, which is conducive to the miniaturization of the camera module, thereby achieving the effect of reducing the thickness of the terminal device (such as a mobile phone) containing the camera module.

[0044] The beneficial effects of the embodiments of the second to third aspects described above can be referred to the beneficial effects of the first aspect and the embodiments of the first aspect described above, and will not be repeated here.

[0045] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0047] Figure 1aA schematic diagram of the optical system of Example 1 in this application is shown;

[0048] Figure 1b The polychromatic light diffraction MTF of the optical system of Example 1 in this application is shown;

[0049] Figure 1c The relative illumination curve of the optical system in Example 1 of this application is shown;

[0050] Figure 1d The field curvature and distortion curves of the optical system in Example 1 of this application are shown;

[0051] Figure 1e The axial aberration curves of the optical system of Example 1 in this application are shown;

[0052] Figure 1f The transverse chromatic aberration curve of the optical system of Example 1 in this application is shown;

[0053] Figure 2a A schematic diagram of the optical system in Example 2 of this application is shown;

[0054] Figure 2b The polychromatic light diffraction MTF of the optical system of Example 2 in this application is shown;

[0055] Figure 2c The relative illumination curve of the optical system in Example 2 of this application is shown;

[0056] Figure 2d The field curvature and distortion curves of the optical system in Example 2 of this application are shown;

[0057] Figure 2e The axial aberration curves of the optical system in Example 2 of this application are shown;

[0058] Figure 2f The transverse chromatic aberration curve of the optical system in Example 2 of this application is shown;

[0059] Figure 3a A schematic diagram of the optical system in Example 3 of this application is shown;

[0060] Figure 3b The polychromatic light diffraction MTF of the optical system of Example 3 in this application is shown;

[0061] Figure 3c The relative illumination curve of the optical system in Example 3 of this application is shown;

[0062] Figure 3d The field curvature and distortion curves of the optical system in Example 3 of this application are shown;

[0063] Figure 3eThe axial aberration curves of the optical system in Example 3 of this application are shown;

[0064] Figure 3f The transverse chromatic aberration curve of the optical system in Example 3 of this application is shown;

[0065] Figure 4 This paper shows a schematic diagram of the camera module without a dimming element in this application;

[0066] Figure 5 This invention illustrates a schematic diagram of the camera module with an added second dimming element.

[0067] Figure 6 It shows the Figure 5 A schematic diagram of the structure of a camera module with an improved second dimming element;

[0068] Figure 7 A schematic diagram of the effective imaging area and the ineffective imaging area in the imaging surface of the imaging chip in this application is shown;

[0069] Figure 8 It shows the Figure 4 A schematic diagram of the structure of a camera module that integrates an imaging chip with optical focusing and image stabilization motors;

[0070] Figure 9 It shows the Figure 5 A schematic diagram of the structure of a camera module that integrates an imaging chip with optical focusing and image stabilization motors;

[0071] Figure 10 It shows the Figure 4 A schematic diagram of a camera module in which an optical focusing motor is installed on the imaging chip and an optical image stabilization motor is installed on the first dimming component;

[0072] Figure 11 It shows the Figure 5 A schematic diagram of a camera module in which an optical focusing motor is installed on the imaging chip and an optical image stabilization motor is installed on the first dimming component;

[0073] Figure 12 It shows that Figure 5 A schematic diagram of a camera module in which the imaging chip and the second dimming component are assembled together, an optical focusing motor is installed on the imaging chip, and an optical image stabilization motor is installed on the first dimming component.

[0074] Figure 13 A schematic diagram of a terminal device equipped with a camera module is shown. Detailed Implementation

[0075] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0076] The accompanying drawings illustrate various structural schematics according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0077] In the description of this application, it should be noted that the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this application, unless otherwise stated, "multiple" means two or more. In the formulas listed herein, "*" represents a multiplication sign, and " / " represents a division sign.

[0078] The implementation details of the technical solutions in the embodiments of this application are described in detail below:

[0079] Reference Figure 1a The diagram shows a schematic representation of an optical system 100 according to an embodiment of this application. The optical system 100 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. The first lens L1, second lens L2, third lens L3, and fourth lens L4 are arranged sequentially from the object side to the image side of the optical system. Each lens is independent of the others, and there is an air gap between each lens along the optical axis. The first lens L1, second lens L2, third lens L3, and fourth lens L4 are located on the same optical axis.

[0080] The optical system 100 satisfies the following relationship: 0.445≤f1 / f≤0.481, where f1 is the focal length of the first lens L1 and f is the focal length of the optical system 100; f1 / f2<0, f3 / f4<0, |f4 / f3|>1, where f1, f2, f3 and f4 are the focal lengths of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4, respectively.

[0081] It is important to understand that the first lens L1 plays a role in converging a portion of the light, the second lens L2 has positive and negative optical power relative to the first lens L1, and the fourth lens L4 has positive optical power relative to the third lens L3, which can better correct chromatic aberration. The fourth lens L1 has a much larger focal length than the third lens L3, which makes the light focusing ability of the fourth lens L4 very small, which is beneficial for correcting the edge aberration of the optical system.

[0082] According to the above-described embodiment of the present invention, the optical system 100 rationally allocates parameters such as optical power and focal length of each lens through the above-described relationship, which can ensure a large aperture of F no < 2.5, achieve a larger amount of light transmission, and increase the amount of information captured by the lens. It has the characteristics of wide imaging range and high imaging quality. That is, under the premise that the optical system 100 has a large aperture, it can also achieve a ratio of NA (entrance pupil diameter) to waist lens diameter D greater than 0.95. That is, while achieving a large aperture, the local diameter of the lens is small, which is conducive to the miniaturization of the camera module, thereby achieving the effect of reducing the thickness of the terminal device (such as a mobile phone) containing the camera module.

[0083] In some embodiments of this application, the optical system satisfies the following relationships: 23.7≤|V2-V1|≤31, 26.8≤|V4-V3|≤38.2, where V1, V2, V3 and V4 are the Abbe numbers of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4, respectively.

[0084] It is important to understand that by ensuring that the Abbe numbers of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 satisfy the above relationship, a combination of high and low dispersion coefficients can be achieved, thereby better correcting chromatic aberration.

[0085] In some embodiments of this application, the optical system 100 satisfies the following relationship: 184.8≤BFL*FOV≤231.77, where BFL is the back focal length of the optical system 100 and FOV is the field of view of the optical system 100.

[0086] It is important to understand that by making the back focal length and FOV of the optical system 100 satisfy the above relationship, the back focal length and FOV of the optical system 100 can be balanced, ensuring that there is a large image height and a large field of view while maintaining a low optical back focal length.

[0087] In some embodiments of this application, a filter IR and an aperture stop are also included. The aperture stop is located on the incident surface side of the first lens L1, and the filter IR is located on the exit surface side of the fourth lens L4. The filter IR satisfies the following relationship: 0.134≤dIR / n5≤0.138, where dIR represents the thickness of the filter IR and n5 represents the refractive index of the filter IR.

[0088] Optionally, the optical system 100 may also include a protective glass for protecting the photosensitive element located on the imaging surface.

[0089] It is important to understand that the IR filter is placed after the optical system 100. The IR filter is used to correct the chromatic aberration produced by all the lenses of the IR filter, which has the best effect on correcting chromatic aberration and is conducive to achieving a large aperture and low total length.

[0090] In some embodiments of this application, the optical system 100 satisfies the following relationship: 0.9641≤n2 / n3≤0.9878, where n2 represents the refractive index of the second lens L2 and n3 represents the refractive index of the third lens L3.

[0091] It is important to understand that by ensuring that the refractive indices of the second lens L2 and the third lens L3 satisfy the above relationship, the light transition is smoother, primary aberrations are reduced, and aberration correction is facilitated.

[0092] In some embodiments of this application, the optical system 100 satisfies the following relationship: |R4-R5| / d5*FOV>100, where R4 represents the radius of curvature of the second surface of the second lens L2, R5 represents the radius of curvature of the first surface of the third lens L3, d5 represents the interval between the second lens L2 and the third lens L3, and FOV represents the field of view of the optical system 100.

[0093] It should be understood that by making the second surface curvature radius of the second lens L2, the first surface curvature radius of the third lens L3, the interval characterizing the second lens L2 and the third lens L3, and the field of view of the optical system 100 satisfy the above relationship, the curvature radius, air gap, and field of view are balanced, thereby increasing the field of view of the overall optical path of the optical system 100.

[0094] In some embodiments of this application, the optical system 100 satisfies the following relationship: 0.63≤(|R1|-|R2|) / (|R1|+|R2|)≤0.7865, where R1 represents the radius of curvature of the first surface of the first lens L1 and R2 represents the radius of curvature of the second surface of the first lens L1.

[0095] It should be understood that by making the first surface radius of curvature of the first lens L1 and the second surface radius of curvature of the first lens L1 satisfy the above relationship, the shape of the first lens can be controlled, so that the first lens can effectively correct the spherical aberration of the optical system.

[0096] In some embodiments of this application, the optical system 100 satisfies the following relationship:

[0097] 0.418≤BFL / TTL≤0.514, where BFL represents the back focal length of optical system 100 and TTL represents the total length of optical system 100.

[0098] It should be noted that the total length of the optical system 100 is defined as the distance between the first lens L1 and the imaging plane.

[0099] It is important to understand that by ensuring that the back focal length of the optical system 100 and the total length of the optical system satisfy the above relationship, the telephoto ratio (total optical length / focal length) can be less than 1.01, the total optical length is short, the lens structure is more compact, and the lens is made smaller.

[0100] In an exemplary embodiment, at least one of the mirror surfaces of each lens is an aspherical mirror surface; that is, at least one mirror surface from the object side of the first lens to the image side of the eighth lens is an aspherical mirror surface. Aspherical lenses are characterized by a continuously changing curvature from the lens center to the lens periphery. Unlike spherical lenses, which have a constant curvature from the lens center to the lens periphery, aspherical lenses have better curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism.

[0101] By using aspherical lenses, aberrations that occur during imaging can be eliminated as much as possible, thereby improving image quality.

[0102] However, those skilled in the art will understand that the number of lenses constituting the optical system 100 can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although four lenses are described as an example in the embodiment, the optical system 100 is not limited to including four lenses, and may include other numbers of lenses if necessary.

[0103] Examples of the optical system 100 applicable to the above embodiments are further described below with reference to the accompanying drawings. Specifically, three examples are given.

[0104] Table 1 below shows the parameters that satisfy the above conditions for three examples:

[0105] Table 1

[0106]

[0107]

[0108] Example 1

[0109] Figure 1a A schematic diagram of the optical system 100 in Example 1 of this application is shown. The specific parameters of the optical system 100 in Example 1 are shown in Tables 2, 3 and 4.

[0110] Table 2 below shows the basic parameters of the optical system 100 in Example 1.

[0111] Table 2

[0112] focal length 13.45mm equivalent focal length 72.7mm band 470-650nm aperture 2.38 Imaging circle 8.5mm Field of view 33° Overall optical length 13.59mm Number of lenses 4 pieces

[0113] Tables 3 and 4 below show the basic parameters of each lens in the optical system 100. The units for radius of curvature, thickness, aperture and focal length are all mm.

[0114] Table 3

[0115]

[0116] Table 4

[0117]

[0118]

[0119] As can be seen from Table 3, the maximum aperture of the waist of the optical system 100 in Example 1 (second lens L2, third lens L3 and fourth lens L4) is 5.36 mm, which is smaller than the aperture diameter of 5.6 mm in Example 1, thus achieving a reduction in the maximum aperture of the waist.

[0120] Figure 1b The diagram shows the polychromatic light diffraction MTF of Example 1 of the optical system 100 in this application. The horizontal axis represents frequency, and the vertical axis represents the MTF value (i.e., OTF modulus). A higher MTF value indicates better imaging performance. The MTF gradually decreases as the frequency increases. Figure 1b It can be seen that the MTF is close to the diffraction limit, indicating a good effect. Figure 1c The figure shows the relative illumination curve of example 1 of the optical system 100 in this application. The horizontal axis represents the image height, and the vertical axis represents the relative illumination value. The image height represents the highest value of 100% (0). The relative illumination value gradually decreases as the image height increases. Figure 1c It can be seen that the relative illuminance is greater than 75%, and the brightness of the image is uniform. Figure 1d The field curvature and distortion curves of Example 1 of the optical system 100 in this application are shown. In the field curvature curve, the horizontal axis represents the field curvature value, and the vertical axis represents the image height. Different curves represent the field curvature values ​​of different colors of light at different image heights. In the distortion curve, the horizontal axis represents the distortion magnitude, and the vertical axis represents the image height. Different curves represent the distortion magnitude of different colors of light at different image heights. Figure 1d As can be seen, the field curvature is less than 0.06 nm and the distortion is less than 2%, indicating that both the field curvature and distortion are well corrected. Figure 1eThe figure shows the axial aberration curves of optical system 100 example 1 in this application. The horizontal axis represents the aberration magnitude, and the vertical axis represents the normalized aperture. Different curves represent the aberration magnitudes of different colors of light at different apertures. Figure 1e It can be seen that when the axial aberration is 0.707, the aperture is less than 0.03 mm, indicating that the correction is relatively good. Figure 1f The figure shows the chromatic aberration curve of the optical system 100 example 1 in this application. The horizontal axis represents the magnitude of chromatic aberration, and the vertical axis represents the image height. Different curves represent the magnitude of chromatic aberration of different colors of light at different image heights. Figure 1f It can be seen that the vertical color difference is within ±2µm, which is well corrected.

[0121] according to Figures 1b to 1f As can be seen from the figure, the optical system 100 given in Example 1 can achieve good imaging quality.

[0122] Example 2

[0123] Figure 2a A schematic diagram of the optical system 100 in Example 2 of this application is shown. The specific parameters of the optical system 100 in Example 2 are shown in Tables 5, 6 and 7.

[0124] Table 5 below shows the basic parameters of the optical system 100 in Example 2.

[0125] Table 5

[0126] focal length 16mm equivalent focal length 86.5mm band 470~650nm aperture 2.4 Imaging circle 8.1 Field of view 28° Overall optical length 15.8mm Number of lenses 4 pieces

[0127] Tables 6 and 7 below show the basic parameters of each lens in the optical system 100. The units for radius of curvature, thickness, aperture and focal length are all mm.

[0128] Table 6

[0129]

[0130] Table 7

[0131]

[0132]

[0133] As can be seen from Table 6, the maximum aperture of the waist of the optical system 100 in Example 2 (the second lens L2, the third lens L3 and the fourth lens L4) is 6.0 mm, which is smaller than the aperture diameter of 6.59 mm in this Example 2, thus achieving a reduction in the maximum aperture of the waist.

[0134] Figure 2bThe diagram shows the polychromatic light diffraction MTF of Example 1 of the optical system 100 in this application. The horizontal axis represents frequency, and the vertical axis represents the MTF value (i.e., OTF modulus). A higher MTF value indicates better imaging performance. The MTF gradually decreases as the frequency increases. Figure 2b It can be seen that the MTF is close to the diffraction limit, indicating a good effect. Figure 2c The figure shows the relative illumination curve of example 1 of the optical system 100 in this application. The horizontal axis represents the image height, and the vertical axis represents the relative illumination value. The image height represents the highest value of 100% (0). The relative illumination value gradually decreases as the image height increases. Figure 2c It can be seen that the relative illuminance is greater than 78%, and the brightness of the image is uniform. Figure 2d The field curvature and distortion curves of Example 1 of the optical system 100 in this application are shown. In the field curvature curve, the horizontal axis represents the field curvature value, and the vertical axis represents the image height. Different curves represent the field curvature values ​​of different colors of light at different image heights. In the distortion curve, the horizontal axis represents the distortion magnitude, and the vertical axis represents the image height. Different curves represent the distortion magnitude of different colors of light at different image heights. Figure 2d As can be seen, the field curvature is less than 0.03 nm and the distortion is less than 3%, indicating that both the field curvature and distortion are well corrected. Figure 2e The figure shows the axial aberration curves of optical system 100 example 1 in this application. The horizontal axis represents the aberration magnitude, and the vertical axis represents the normalized aperture. Different curves represent the aberration magnitudes of different colors of light at different apertures. Figure 2e It can be seen that when the axial aberration is 0.707, the aperture is less than 0.03 mm, indicating that the correction is relatively good. Figure 2f The figure shows the chromatic aberration curve of the optical system 100 example 1 in this application. The horizontal axis represents the magnitude of chromatic aberration, and the vertical axis represents the image height. Different curves represent the magnitude of chromatic aberration of different colors of light at different image heights. Figure 2f It can be seen that the vertical color difference is within ±2µm, which is well corrected.

[0135] according to Figures 2b to 2f As shown, the optical system 100 given in Example 2 can achieve good imaging quality.

[0136] Example 3

[0137] Figure 3a A schematic diagram of the optical system 100 in Example 1 of this application is shown. The specific parameters of the optical system 100 in Example 1 are shown in Tables 8, 9 and 10:

[0138] The following 8 are the basic parameters of the optical system 100 in Example 3.

[0139] Table 8

[0140] focal length 13.6 equivalent focal length 66.8mm band 470~650nm aperture 2.4 Imaging circle 8.8 Field of view 36° Overall optical length 13.45mm Number of lenses 4 pieces

[0141] Tables 3 and 4 below show the basic parameters of each lens in the optical system. The units for radius of curvature, thickness, aperture, and focal length are all mm.

[0142] Table 9

[0143]

[0144] Table 10

[0145]

[0146] As can be seen from Table 9, the maximum waist diameter (second lens L2, third lens L3 and fourth lens L4) of the optical system 100 in Example 3 is 5.33 mm, which is smaller than the aperture diameter of 5.61 mm in Example 2, thus achieving a reduction in the maximum waist diameter.

[0147] Figure 3b The diagram shows the polychromatic light diffraction MTF of Example 1 of the optical system 100 in this application. The horizontal axis represents frequency, and the vertical axis represents the MTF value (i.e., OTF modulus). A higher MTF value indicates better imaging performance. The MTF gradually decreases as the frequency increases. Figure 3b It can be seen that the MTF is close to the diffraction limit, indicating a good effect. Figure 3c The figure shows the relative illumination curve of example 1 of the optical system 100 in this application. The horizontal axis represents the image height, and the vertical axis represents the relative illumination value. The image height represents the highest value of 100% (0). The relative illumination value gradually decreases as the image height increases. Figure 3c It can be seen that the relative illuminance is greater than 68%, and the brightness of the image is uniform. Figure 3d The field curvature and distortion curves of Example 1 of the optical system 100 in this application are shown. In the field curvature curve, the horizontal axis represents the field curvature value, and the vertical axis represents the image height. Different curves represent the field curvature values ​​of different colors of light at different image heights. In the distortion curve, the horizontal axis represents the distortion magnitude, and the vertical axis represents the image height. Different curves represent the distortion magnitude of different colors of light at different image heights. Figure 3d As can be seen, the field curvature is less than 0.12 nm and the distortion is less than 3%, indicating that both the field curvature and distortion are well corrected. Figure 3e The figure shows the axial aberration curves of optical system 100 example 1 in this application. The horizontal axis represents the aberration magnitude, and the vertical axis represents the normalized aperture. Different curves represent the aberration magnitudes of different colors of light at different apertures. Figure 3e It can be seen that when the axial aberration is 0.707, the aperture is less than 0.02 mm, indicating that the correction is relatively good. Figure 3fThe figure shows the chromatic aberration curve of the optical system 100 example 1 in this application. The horizontal axis represents the magnitude of chromatic aberration, and the vertical axis represents the image height. Different curves represent the magnitude of chromatic aberration of different colors of light at different image heights. Figure 3f It can be seen that the vertical color difference is within ±2.2µm, which is well corrected.

[0148] according to Figures 3b to 3f As can be seen from the figure, the optical system 100 given in Example 3 can achieve good imaging quality.

[0149] Reference Figure 4 The diagram shows a schematic representation of the camera module 10 in this embodiment. The camera module 10 includes an optical system 100, a first dimming element 200, and an imaging chip 300. Externally incident light passes through the first dimming element 200 and enters the optical system 100, then exits the optical system 100 and enters the imaging chip 300 for imaging.

[0150] For example, the first dimming element 200 can be a prism or a plane mirror.

[0151] It should be understood that by adopting a periscope optical path based on the aforementioned optical system 100, that is, by deflecting the object-side incident light by 90 degrees through the first dimming element 200 and exiting the optical system 100 to the imaging chip 300 for imaging, the thickness of the mobile phone can be reduced to a greater extent.

[0152] In some embodiments of this application, reference is made to Figure 5 As shown, the imaging surface of the imaging chip 300 is arranged parallel to the optical axis of the optical system 100 (i.e., along the Z-axis direction in the figure). The camera module 10 also includes a second dimming element 400. The second dimming element 400 is located in the light transmission path between the optical system 100 and the imaging chip 300. Light rays emitted from the optical system 100 are deflected by the second dimming element 400 to the imaging chip 300 for imaging.

[0153] For example, the second dimming element 400 can be a prism or a plane mirror.

[0154] It is important to understand that by deflecting the light emitted from the optical system 100 by 90 degrees through the second dimming element 400 to the imaging chip 300 for imaging, it is possible to shorten the thickness of the phone without increasing its length.

[0155] In some embodiments of this application, reference is made to Figure 6As shown, the second dimming element 400 includes an incident light surface 401, an emitted light surface 402, a reflective surface 403, a first connecting surface 404, and a second connecting surface 405. The first connecting surface 404 connects the reflective surface 403 and the incident light surface 401, and the second connecting surface 405 connects the reflective surface 403 and the emitted light surface 402.

[0156] For example, the first connecting surface 404 is a plane parallel to the light-emitting surface 402, and the second connecting surface 405 is a plane parallel to the light-incident surface 401.

[0157] It is important to understand that, referring to Figure 6 and Figure 7 As shown, in order to reduce the thickness of the rear assembly, a new structure was designed for the second dimming element 400 (e.g. Figure 6 As shown), generally, the effective imaging portion S1 of the imaging surface on the imaging circle where the imaging chip 300 is located is rectangular. In the new structure, the short side of the effective imaging portion S1 of the imaging surface of the imaging chip 300 is required to be perpendicular to the optical axis of the optical system 100, and the long side of the effective imaging portion S2 of the imaging surface of the imaging chip 300 is required to be parallel to the optical axis of the optical system 100. Since the square imaging chip 300 only utilizes the portion within the rectangle of the imaging circle of the optical system 100 (i.e., the effective imaging portion S1), the remaining portion outside the rectangle is the ineffective imaging portion S2 (see reference). Figure 7 As shown), the two 45° angle portions of the second dimming element 400 are cut off. This cuts off the invalid light and reduces the thickness of the phone. It should be noted that the size of the cut-off varies for different parameters of the optical system 100, so as not to affect the imaging within the 0.6 field of view.

[0158] In some embodiments of this application, reference is made to Figure 8 As shown, it also includes: an optical focusing and image stabilization motor 500, and an imaging chip 300 disposed in the optical focusing and image stabilization motor 500;

[0159] The optical focusing and image stabilization motor 500 is used to drive the imaging chip 300 to move along the optical axis of the imaging chip 300 (i.e., along the Z-axis direction in the figure) to achieve focusing, and to drive the imaging chip 300 to move in a direction parallel to the imaging surface of the imaging chip 300 (i.e., along the XY plane direction in the figure) to achieve image stabilization.

[0160] It should be noted that this focusing and image stabilization solution is applicable to camera modules 10 without a second dimming unit 400 (such as...). Figure 8 (as shown) or after adding a second dimming element 400 to the camera module 10 (such as... Figure 9 (As shown) Two focusing schemes.

[0161] In the focusing scheme of the camera module 10 without the addition of the second dimming element 400, such as Figure 8As shown, the optical focusing and image stabilization motor 500a is used to move the imaging chip 300 along the Z-axis direction in the figure to achieve focusing, and to move the imaging chip 300 along the XY plane direction in the figure to achieve image stabilization.

[0162] In the focusing scheme of the camera module 10 with the addition of the second dimming element 400, such as Figure 9 As shown, the optical focusing and image stabilization motor 500b is used to move the imaging chip 300 along the Z-axis direction in the figure to achieve focusing, and to move the imaging chip 300 along the XZ plane direction in the figure to achieve image stabilization.

[0163] It is important to understand that this approach enables the entire camera module 10 to focus and stabilize on the same end of the imaging chip 300.

[0164] In some embodiments of this application, reference is made to Figure 10 and Figure 11 As shown, it also includes: an optical focusing motor 600a and an optical image stabilization motor 700a, with the imaging chip 300 disposed on the optical focusing motor 600a and the first dimming element 200 disposed on the optical image stabilization motor 700a.

[0165] The optical focusing motor 600a is used to drive the imaging chip 300 to move along the optical axis of the imaging chip 300 to achieve focusing, and the optical image stabilization motor 700a is used to drive the first dimming element 200 to move in a direction parallel to the imaging surface of the imaging chip 300 to achieve image stabilization.

[0166] It should be noted that this focusing and image stabilization solution is applicable to camera modules 10 without a second dimming unit 400 (such as...). Figure 10 (as shown) or after adding a second dimming element 400 to the camera module 10 (such as... Figure 11 (As shown) Two focusing schemes.

[0167] In the focusing scheme of the camera module 10 without the addition of the second dimming element 400, such as Figure 10 As shown, the optical focusing motor 600a is used to drive the imaging chip 300 to move along the Z-axis to achieve focusing, and the optical image stabilization motor 700a is used to drive the first dimming element 200 to move along the XY plane to achieve image stabilization.

[0168] In the focusing scheme of the camera module 10 without the addition of the second dimming element 400, such as Figure 11 As shown, the optical focusing motor 600b is used to drive the imaging chip 300 to move along the Z-axis to achieve focusing, and the optical image stabilization motor 700b is used to drive the first dimming element 200 to move along the XZ plane to achieve image stabilization.

[0169] It is important to understand that this approach enables the entire camera module 10 to focus at the imaging chip 300 end and to stabilize the image at the first dimming element 400 end.

[0170] In some embodiments of this application, reference is made to Figure 12 As shown, the system also includes an optical focusing motor 600b and an optical image stabilization motor 700b. The imaging chip 300 and the second dimming element 400 are assembled together and disposed on the optical focusing motor 600b, while the first dimming element 200 is disposed on the optical image stabilization motor 700b. The optical focusing motor 600b is used to drive the second dimming element 400 and the imaging chip 400 together to move along the optical axis direction of the optical system 300 (i.e., the Z-axis direction in the figure) to achieve focusing. The optical image stabilization motor 700b is used to drive the first dimming element 200 to move in a direction parallel to the imaging surface of the imaging chip 300 (i.e., the XZ plane direction in the figure) to achieve image stabilization.

[0171] It is important to understand that during the focusing process, the optical focusing motor 600b drives the second dimming element 200 and the imaging chip 300 to move together along the optical axis of the optical system 100 (i.e., the Z-axis direction in the figure) to achieve focusing. The advantage of this focusing method is that by setting the second dimming element 200 to deflect the light from the Z-axis to the Y-axis, the length of the camera module 10 along the optical axis of the optical system 100 (i.e., the Z-axis direction in the figure) is shortened. Furthermore, by making the imaging chip 300 focus on the Z-axis in the figure, the focus on the direction perpendicular to the imaging surface of the imaging chip 300 (i.e., the Y-axis direction) is avoided, which would increase the thickness of the mobile phone.

[0172] Reference Figure 13 The diagram shows a schematic diagram of the structure of the terminal device 1 in the embodiment of this application. The terminal device 1 includes a camera module 10.

[0173] It should be understood that the terminal device 1 includes the aforementioned camera module 10, which enables the terminal device 1, such as a mobile phone or tablet, to be made thinner and lighter.

[0174] In some embodiments of this application, reference is made to Figure 13 As shown, the terminal device 1 further includes: a housing 11, a first receiving cavity 111 is provided inside the housing 11, a camera protective cover 12, the camera protective cover 12 protrudes from the outside of the housing 11 to form a second receiving cavity 121 that communicates with the first receiving cavity 111, and an optical system 100 is partially located in the second receiving cavity 121, with the optical axis of the optical system 100 perpendicular to the thickness direction of the camera protective cover 12 (i.e., the Y-axis direction in the figure).

[0175] It should be noted that the portion located in the second receiving cavity 121 is not limited to the optical system 100. The first dimming element 200 and the second dimming element 400, together with the optical system 100, or even a portion of the imaging chip 300, can also be placed in the second receiving cavity 121.

[0176] It should be understood that the optical system 100 is located in the second receiving cavity 121, which can place at least a part of the relatively large optical system 100 in the second receiving cavity 121 and the rest in the first receiving cavity 111. The height of the camera protective cover 12 can be used to further reduce the depth of the first receiving cavity 111, thereby making the terminal device 1 such as the mobile phone or tablet thinner and lighter.

[0177] It should also be noted that the accompanying drawings of the embodiments of this application only involve structures relevant to the embodiments of this application; other structures can refer to general designs. Where there is no conflict, the embodiments of this application and the features described therein can be combined to obtain new embodiments.

[0178] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A camera module, characterized in that, Applied to terminal devices, the camera module includes a first dimming element, an optical system, and an imaging chip. External incident light is deflected by 90 degrees through the first dimming element, passes through the optical system, and exits to the imaging chip for imaging. The optical axis of the optical system is perpendicular to the thickness direction of the terminal device. The optical system includes a first lens, a second lens, a third lens, and a fourth lens, and the optical system has four lenses with optical power. The first lens, the second lens, the third lens, and the fourth lens are arranged sequentially from the object side to the image side of the optical system. The first lens has positive optical power, and the second lens has negative optical power. The first lens, the second lens, the third lens, and the fourth lens are located on the same optical axis; The optical system satisfies the following relationship: f1 / f2=-0.665, f3 / f4=-0.107, |f4 / f3|=9.31, f1 / f=0.445; or, f1 / f2=-0.885, f3 / f4=-0.293, |f4 / f3|=3.43, f1 / f=0.481; or, f1 / f2=-0.861, f3 / f4=-0.779, |f4 / f3|=1.285, f1 / f=0.453; where f1, f2, f3 and f4 are the focal lengths of the first lens, the second lens, the third lens and the fourth lens, respectively, and f is the focal length of the optical system.

2. The camera module according to claim 1, characterized in that, The optical system satisfies the following relationship: 0.9641≤n2 / n3≤0.9878, where n2 represents the refractive index of the second lens and n3 represents the refractive index of the third lens.

3. The camera module according to claim 1, characterized in that, The optical system satisfies the following relationship: |R4-R5| / d5*FOV>100°, where R4 represents the radius of curvature of the second surface of the second lens, R5 represents the radius of curvature of the first surface of the third lens, d5 represents the interval between the second lens and the third lens, and FOV represents the field of view of the optical system.

4. The camera module according to any one of claims 1-3, characterized in that, The imaging chip's imaging surface is arranged parallel to the optical axis of the optical system, and it further includes: The second dimming element is located in the light transmission path between the optical system and the imaging chip. The light emitted from the optical system is deflected by the second dimming element to the imaging chip for imaging.

5. The camera module according to claim 4, characterized in that, The second dimming element includes an incident light surface, an emitted light surface, a reflective surface, a first connecting surface, and a second connecting surface. The first connecting surface is connected between the reflective surface and the incident light surface, and the second connecting surface is connected between the reflective surface and the emitted light surface.

6. The camera module according to any one of claims 1-3, characterized in that, Also includes: An optical focusing and image stabilization motor, wherein the imaging chip is disposed in the optical focusing and image stabilization motor; The optical focusing and image stabilization motor is used to drive the imaging chip to move along the optical axis of the imaging chip to achieve focusing, and to drive the imaging chip to move in a direction parallel to the imaging surface of the imaging chip to achieve image stabilization.

7. The camera module according to any one of claims 1-3, characterized in that, Also includes: An optical focusing motor and an optical image stabilization motor are provided, with the imaging chip disposed on the optical focusing motor and the first dimming element disposed on the optical image stabilization motor. The optical focusing motor is used to drive the imaging chip to move along the optical axis of the imaging chip to achieve focusing, and the optical image stabilization motor is used to drive the first dimming element to move in a direction parallel to the imaging surface of the imaging chip to achieve image stabilization.

8. The camera module according to claim 4, characterized in that, It also includes an optical focusing motor and an optical image stabilization motor. The imaging chip and the second dimming element are assembled together and disposed on the optical focusing motor, and the first dimming element is disposed on the optical image stabilization motor. The optical focusing motor is used to drive the second dimming element and the imaging chip together to move along the optical axis of the optical system to achieve focusing, and the optical image stabilization motor is used to drive the first dimming element to move in a direction parallel to the imaging surface of the imaging chip to achieve image stabilization.

9. A terminal device, characterized in that, include: The camera module according to any one of claims 1-8, and: A housing, wherein a first receiving cavity is provided on the inner side of the housing; Camera protective cover; The camera protective cover protrudes from the outside of the housing, forming a second receiving cavity that communicates with the first receiving cavity. The optical system is located within the second receiving cavity, and the optical axis of the optical system is perpendicular to the thickness direction of the camera protective cover.

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