Camera module and electronic device

Abstract

The application relates to a camera module and electronic equipment. The camera module comprises a first lens with positive focal length, the object side is convex at the near optical axis; a second lens with positive focal length, the object side is convex at the near optical axis, and the image side is concave at the near optical axis; a third lens with negative focal length, the object side and the image side are both concave at the near optical axis; a fourth lens with negative focal length, the object side of the fourth lens is convex at the near optical axis, and the image side is concave at the near optical axis; wherein the camera module has an imaging surface on the image side of the fourth lens, the fourth lens is fixed relative to the imaging surface, the first lens, the second lens and the third lens form a focusing lens group, and the focusing lens group can move along the optical axis relative to the fourth lens. The above-mentioned camera module can shorten the focusing stroke of the focusing lens group, thereby being beneficial to compressing the occupied space of the focusing driving element.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of camera technology, in particular to a camera module and an electronic device. BACKGROUND

[0002] A conventional camera module usually includes a lens group and an image sensor, and incident light is imaged on the image sensor after being adjusted by each lens in the lens group. In a conventional camera module, a focusing driving element such as a voice coil motor is usually arranged to move the lens group or the image sensor to achieve the optical focusing function of the camera module. However, the arrangement of the focusing driving element in the conventional camera module is likely to cause the excessive increase of the occupied space of the camera module, which is not conducive to the miniaturization design of the camera module. SUMMARY

[0003] Embodiments of the present application provide a camera module and an electronic device to compress the occupied space of the camera module while achieving the optical focusing function.

[0004] A camera module includes a focusing lens group and a fourth lens arranged on the image side of the focusing lens group, the position of the fourth lens is fixed relative to the imaging surface of the camera module, and the focusing lens group can move along the optical axis relative to the fourth lens.

[0005] The focusing lens group includes, in order from the object side to the image side along the optical axis, a first lens with positive refractive power, a second lens with positive refractive power, and a third lens with negative refractive power. The object side surface of the first lens is convex at the near optical axis, the object side surface of the second lens is convex at the near optical axis, and the image side surface of the second lens is concave at the near optical axis. The object side surface and the image side surface of the third lens are both concave at the near optical axis. The fourth lens has negative refractive power, the object side surface of the fourth lens is convex at the near optical axis, and the image side surface of the fourth lens is concave at the near optical axis.

[0006] An electronic device includes the camera module according to any one of the above embodiments.

[0007] The camera module is designed by the power and surface shape of each lens, so that each lens can jointly cooperate to constrain the trend of the light path, suppress various aberrations such as distortion, improve the imaging quality of the camera module, and realize long-focus design. Moreover, the camera module realizes the inner focusing function by the movement of the focusing lens group composed of the first lens, the second lens and the third lens on the optical axis, which can effectively shorten the focusing stroke of the focusing lens group under the same range of object distance change while realizing long-focus design, thereby being beneficial to compress the occupied space of the focusing driving element of the focusing lens group, and further being beneficial to compress the volume of the camera module and realize miniaturization design. In addition, the design of moving the first lens, the second lens and the third lens as a whole relative to the fourth lens to realize focusing, in cooperation with the power and surface shape design of each lens, can effectively correct the aberration under different object distance states, reasonably constrain the light path trend under different object distance states, so that the camera module can have good imaging quality under different object distance states. BRIEF DESCRIPTION OF DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0009] Figure 1 The structure schematic diagram of the electronic device in some embodiments.

[0010] Figure 2 The structure schematic diagram of the camera module in the first embodiment.

[0011] Figure 3 The light path schematic diagram of the optical transmission element reflecting light three times in some embodiments.

[0012] Figure 4 The structure schematic diagram of the optical transmission element in some embodiments.

[0013] Figure 5 The structure schematic diagram of the camera module in the second embodiment.

[0014] Figure 6 The structure schematic diagram of the camera module in the third embodiment.

[0015] Figure 7 The astigmatism curve and distortion curve of the camera module in the first embodiment.

[0016] Figure 8 The astigmatism curve and distortion curve of the camera module in the second embodiment.

[0017] Figure 9 The astigmatism curve and the distortion curve of the camera module in the third embodiment.

[0018] Figure 10 The structural schematic diagram of the electronic device further comprising other components in some embodiments.

[0019] Reference signs:

[0020] 10, electronic device; 11, housing; 111, light inlet; 20, camera module; 21, focusing lens group; L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; 22, imaging surface; 23, image sensor; 24, focusing driving element; 25, diaphragm; 26, filter; 27, optical conducting element; 271, light transmission surface; 2711, light inlet area; 2712, light outlet area; 272, first reflecting surface; 273, second reflecting surface; 274, bottom surface. DETAILED DESCRIPTION

[0021] For the purpose of facilitating the understanding of the present application, a more complete description of the present application will be provided below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0022] As used herein, “electronic device” refers to, but is not limited to, a device capable of receiving and / or transmitting communication signals via any one or more of the following connection methods:

[0023] (1) via a wired connection method, such as via a public switched telephone network (PSTN), a digital subscriber line (DSL), a digital cable, a direct cable connection;

[0024] (2) via a wireless interface method, such as a cellular network, a wireless local area network (WLAN), a digital television network such as a DVB-H network, a satellite network, an AM-FM broadcast transmitter.

[0025] An electronic device configured to communicate via a wireless interface can be referred to as a “mobile terminal”. Examples of mobile terminals include, but are not limited to, the following electronic devices:

[0026] (1) a satellite phone or a cellular phone;

[0027] (2) Personal Communications System (PCS) terminal that can combine a cellular radiotelephone with data processing, facsimile, and data communications capabilities;

[0028] (3) a radiotelephone, a pager, Internet / Intranet access, a Web browser, a notepad, a calendar, a Personal Digital Assistant (PDA) equipped with a Global Positioning System (GPS) receiver;

[0029] (4) a conventional laptop and / or palmtop receiver;

[0030] (5) a conventional laptop and / or palmtop radiotelephone transceiver, etc.

[0031] See Figure 1 and Figure 2 , Figure 1 FIG. 1 is a schematic diagram of an electronic device 10 according to some embodiments, Figure 2 FIG. 2 is a schematic diagram of a camera module 20 according to some embodiments. The camera module 20 provided in the present application includes but is not limited to being used in any applicable electronic device 10 such as a smartphone, a tablet computer, an e-reader, a wearable device, etc. The camera module 20 can capture image information on the object side so that the electronic device 10 has the functions of taking pictures and shooting. In the embodiments of the present application, a smartphone is taken as an example for illustration.

[0032] In some embodiments, the electronic device 10 further includes a housing 11, and the camera module 20 is arranged in the housing 11. The housing 11 can include a middle frame and a back cover plate. The middle frame can be substantially in the shape of a rectangular frame. The back cover plate is arranged on one side of the middle frame. The camera module 20 is located in a receiving space formed by the back cover plate and the middle frame and is exposed to the back cover plate to capture light on the side of the back cover plate of the electronic device 10. The electronic device 10 can further include a display screen. The display screen is arranged on the side of the middle frame opposite to the back cover plate. When the camera module 20 is used to capture light on the side of the back cover plate of the electronic device 10, the camera module 20 can be a rear camera. In other embodiments, the camera module 20 can also be a front camera. In this case, the camera module 20 can be exposed to the side where the display screen is located and be used to capture light on the side where the display screen is located. The electronic device 10 can further include any other applicable components to realize more functions, which are not described in detail in the present application.

[0033] Reference is made to Figure 2 and Figure 3As shown, in some embodiments, the camera module 20 includes, along the optical axis from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. Each lens includes an object side surface facing the object side, and an image side surface facing the image side. The object side surface can be regarded as the light entrance surface of the lens, and the image side surface can be regarded as the light exit surface of the lens. The lenses in the camera module 20 can be coaxially arranged, and the optical axis of the camera module 20 passes through the common axis of the lenses. The camera module 20 further includes an imaging surface 22 located on the image side of the fourth lens L4. The imaging surface 22 can be understood as the converging surface of the light rays from the object side after being adjusted by the lenses on the image side of the fourth lens L4. The imaging surface 22 can be a virtual plane. When the camera module 20 further includes an image sensor 23 located on the image side of the fourth lens L4, the light sensitive surface of the image sensor 23 can coincide with the imaging surface 22, and the light rays from the object side can be sequentially adjusted by the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4, and then conducted to the light sensitive surface of the image sensor 23 to form an image.

[0034] Further, in combination with Figure 2 and Figure 3 As shown, in some embodiments, the first lens L1 has a positive focal power, and the object side surface of the first lens L1 is a convex surface at the near optical axis. The second lens L2 has a positive focal power, and the object side surface of the second lens L2 is a convex surface at the near optical axis, and the image side surface is a concave surface at the near optical axis. The third lens L3 has a negative focal power, and both the object side surface and the image side surface of the third lens L3 are concave surfaces at the near optical axis. The fourth lens L4 has a negative focal power, and the object side surface of the fourth lens L4 is a convex surface at the near optical axis, and the image side surface is a concave surface at the near optical axis. The fourth lens L4 is fixed relative to the imaging surface 22, and the first lens L1, the second lens L2, and the third lens L3 are fixed relative to each other to form a focusing lens group 21. The focusing lens group 21 can move along the optical axis on the object side of the fourth lens L4 relative to the imaging surface 22 to realize the optical focusing function of the camera module 20. The camera module 20 can further include a focusing driving element 24, which includes but is not limited to a voice coil motor, etc. The focusing driving element 24 is used to drive the focusing lens group 21 to move along the optical axis relative to the fourth lens L4 and the imaging surface 22.

[0035] The positive focal length and the convex object side surface of the first lens L1 can effectively converge the incident light towards the image side, which is conducive to realizing the long-focus design and avoiding excessive increase of the total optical length. The positive focal length and the surface type design of the first lens L1 and the second lens L2 complement each other, which can smoothly transition the light collected by the first lens L1 and suppress the generation of aberrations such as distortion, thereby being conducive to improving the imaging quality of the camera module 20 and reducing the burden of the third lens L3 and the fourth lens L4 for deflecting light, reducing the surface type design difficulty of the third lens L3 and the fourth lens L4, and reducing the tolerance sensitivity and aberration sensitivity of the camera module 20. The negative focal length of the third lens L3 and the concave design of the object side surface and the image side surface can converge the light transmitted by the first lens L1 and the second lens L2 towards the image side, which is conducive to increasing the size of the imaging surface 22 and improving the imaging quality. The focal length and surface type design of the third lens L3, in combination with the negative focal length and the convex-concave surface type design of the fourth lens L4, can reasonably transition the light to the imaging surface 22, improve the matching degree of the incident angle of the light on the imaging surface 22 and the image sensor 23, and be conducive to further improving the imaging quality of the camera module 20. Therefore, by designing the focal length and surface type of each lens, the lenses can jointly constrain the trend of the light path, suppress various aberrations such as distortion, improve the imaging quality of the camera module 20, and realize long-focus design.

[0036] In addition, the focusing lens group 21 composed of the first lens L1, the second lens L2, and the third lens L3 can realize the internal focusing function by moving on the optical axis, and the focal length of the camera module 20 will also change during the focusing process. Therefore, while realizing the long-focus design, the focusing stroke of the focusing lens group 21 under the same object distance change range can be effectively shortened, the stroke requirement of the focusing driving element 24 of the camera module 20 is reduced, and the design of moving only three lenses is conducive to reducing the load requirement of the focusing driving element 24 of the camera module 20. Therefore, it is conducive to compressing the occupied space of the focusing driving element 24, and further conducive to compressing the volume of the camera module 20, which is conducive to realizing the miniaturization design and facilitating the assembly of the camera module 20 in the electronic device 10. In addition, the design of moving the first lens L1, the second lens L2, and the third lens L3 as a whole relative to the fourth lens L4 to realize focusing, in combination with the focal length and surface type design of each lens, can effectively correct the aberration under different object distance states while reducing the focusing stroke, reasonably constrain the trend of the light path under different object distance states, so that the camera module 20 can have good imaging quality under different object distance states.

[0037] In some embodiments, the camera module 20 is provided with a diaphragm 25, which can be arranged on the object side of the first lens L1, or between any two lenses in other embodiments. In some embodiments, the camera module 20 further comprises a filter 26 arranged between the fourth lens L4 and the imaging surface 22. The filter 26 includes, but is not limited to, an infrared cut-off filter 26, which is used to filter out interference light and prevent interference light from reaching the imaging surface 22 and affecting normal imaging. Of course, the filter 26 can also be replaced with a protective glass, or omitted. When the filter 26 is omitted, the distance between the image side surface of the fourth lens L4 and the imaging surface 22 can remain unchanged.

[0038] In some embodiments, the object side surface and the image side surface of the first lens L1 are both spherical surfaces, and the object side surface and the image side surface of at least one of the second lens L2, the third lens L3 and the fourth lens L4 are both aspherical surfaces. In this application, the object side surface and the image side surface of the second lens L2, the third lens L3 and the fourth lens L4 are all aspherical surfaces. In this way, the design difficulty, the manufacturing cost and the design flexibility can be considered, and the aspherical surface can effectively correct the spherical aberration and other aberrations, which is beneficial to improve the imaging quality of the camera module 20. In some embodiments, the maximum effective aperture of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 decreases in turn, which is beneficial to realize the long-focus design, increase the depth of field of the camera module 20, suppress the spherical aberration, chromatic aberration and other aberrations, reduce the phenomena such as light halo and flare, and thus improve the imaging quality and long-focus shooting experience of the camera module 20. It can be understood that when a surface of a lens is a spherical surface, the surface type at the near optical axis and the circumference is the same, and when a surface of a lens is an aspherical surface, the surface type at the near optical axis and the circumference can be the same or different. The surface type at the circumference can be designed according to the imaging requirements, and in this application, the surface type at the circumference of each aspherical lens is not limited.

[0039] In some embodiments, the material of each lens in the camera module 20 can be glass or plastic. The lens made of plastic material can reduce the weight and production cost of the camera module 20, and cooperate with the small size of the camera module 20 to realize the lightweight design of the camera module 20. The lens made of glass material makes the camera module 20 have excellent optical performance and high temperature resistance. It should be noted that the material of each lens in the camera module 20 can also be any combination of glass and plastic, and it does not have to be all glass or all plastic.

[0040] In some embodiments, the camera module 20 satisfies a condition formula: 0.5≤|EFL1 / F4|≤0.8; where EFL1 is the effective focal length of the focusing lens group 21, and F4 is the effective focal length of the fourth lens L4. For example, |EFL1 / F4| can be 0.5, 0.6, 0.7, or 0.8. When the above condition formula is satisfied, the ratio of the effective focal lengths of the focusing lens group 21 and the fourth lens L4 can be reasonably configured, that is, the distribution relationship of the effective focal lengths of the focusing part and the fixed part of the camera module 20 is reasonably configured, which can effectively reduce the focusing stroke of the focusing lens group 21 while maintaining good imaging quality at different object distance ranges.

[0041] In some embodiments, the camera module 20 satisfies a condition formula: TTL / IMGH≤12; where TTL is the distance from the object side surface of the first lens L1 to the imaging surface 22 on the optical axis, that is, the total optical length of the camera module 20, and IMGH is the half image height of the camera module 20. When the camera module 20 matches an image sensor 23 with a square photosurface, IMGH can be half of the diagonal length of the effective pixel area on the imaging surface 22. For example, TTL / IMGH can be 2, 5, 7, 8, 9, 11, or 12. When the above condition formula is satisfied, the ratio of the total optical length and the half image height of the camera module 20 can be reasonably configured, which is beneficial to improve the matching degree of the camera module 20 structure and the image sensor 23, thereby improving the imaging quality of the camera module 20.

[0042] In some embodiments, the camera module 20 satisfies a condition formula: 8°≤FOV≤20°; where FOV is the maximum field of view angle of the camera module 20. For example, FOV can be 8, 10, 13, 15, 18, or 20, with the unit of °. By reasonably configuring the maximum field of view angle of the camera module 20, the long focal characteristic and the field of view angle can be balanced, so that the camera module 20 has a large enough field of view angle and good imaging quality while realizing long focal design.

[0043] In some embodiments, the camera module 20 satisfies a condition formula: 2.8≤EFL / EPD≤3.8; where EFL is the effective focal length of the camera module 20, and EPD is the entrance pupil diameter of the camera module 20. For example, EFL / EPD can be 2.8, 3, 3.2, 3.5, 3.6, or 3.8. When the above condition formula is satisfied, the relative aperture of the camera module 20 can be designed, which is beneficial to increase the aperture of the camera module 20 and improve the light throughput of the camera module 20, thereby improving the imaging quality of the camera module 20 in a weak light environment.

[0044] In some embodiments, the camera module 20 satisfies the condition: 0.4 ≤ F1 / EFL ≤ 0.6; where F1 is the effective focal length of the first lens L1 and EFL is the effective focal length of the camera module 20. For example, F1 / EFL can be 0.4, 0.5, or 0.6. When the above condition is satisfied, the ratio of the effective focal length of the first lens L1 to the effective focal length of the camera module 20 can be reasonably configured, thereby reasonably allocating the deflection function undertaken by the first lens L1 in the camera module 20. This ensures that the first lens L1 has sufficient deflection force to deflect light rays with a large field of view, achieving effective light collection and improving the imaging quality of the camera module 20. At the same time, it can also avoid excessive deflection force of the first lens L1, which would cause the surface to be too curved. This is beneficial to reducing the tolerance sensitivity and aberration sensitivity of the first lens L1, and reducing the molding and assembly difficulty of the first lens L1.

[0045] In some embodiments, the camera module 20 satisfies the condition: 0.3 ≤ R1 / F1 ≤ 0.7; where R1 is the radius of curvature of the object-side surface of the first lens L1 at the optical axis, and F1 is the effective focal length of the first lens L1. For example, R1 / F1 can be 0.3, 0.4, 0.5, 0.6, or 0.7. When the above condition is satisfied, the ratio of the radius of curvature of the object-side surface of the first lens L1 to the effective focal length of the first lens L1 can be reasonably configured, which is beneficial to suppressing spherical aberration and chromatic aberration generated by the first lens L1, and also to avoiding strong total internal reflection ghosting caused by excessive deflection angle in the first lens L1, thereby improving the imaging quality of the camera module 20.

[0046] Combination Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, the camera module 20 further includes an optical transmission element 27 disposed along the optical axis between the fourth lens L4 and the image sensor 23. The optical transmission element 27 is used to transmit light to the image sensor 23 after at least one reflection. By reflecting light through the optical transmission element 27, the effect of folding the optical path can be achieved, for example, realizing a periscope design. When the camera module 20 is used in the electronic device 10, it is beneficial to reduce the size of the telephoto-designed camera module 20 in the thickness direction of the electronic device 10. It should be noted that, for the convenience of the design of each lens, Figure 2 , Figure 5 and Figure 6 In this method, only a cuboid glass element 27 is replaced with an optical transmission element 27, and the optical path length of light is equal in both the cuboid glass and the optical transmission element 27. However, in... Figure 3 In the illustrated embodiment, four lenses are represented by four elliptical structures. No limitation is shown on the shape or size of the lenses. The shape design of each lens varies in different embodiments. Figure 2 , Figure 5 and Figure 6The shape of the optical conducting element 27 in one embodiment is designed as shown in Figure 3 and Figure 4 .

[0047] In some embodiments, the optical conducting element 27 is configured to conduct the light to the image sensor 23 after at least two reflections, so that the axis of the fourth lens L4 is perpendicular to the imaging surface 22, that is, the optical conducting element 27 can fold the light path by 180°, Figure 3 In the illustrated embodiment, the optical conducting element 27 reflects the light path three times. In this way, the optical conducting element 27 can fold the light path by multiple reflections, effectively compressing the volume of the optical conducting element 27, and when the axes of the first lens L1 to the fourth lens L4 are parallel to the thickness direction of the electronic device 10, the image sensor 23 and the optical filter 26 are in the height direction of the electronic device 10, and the size of at least part of the lens is overlapped, which can effectively compress the size of the camera module 20 in the thickness direction of the electronic device 10.

[0048] In combination with Figure 1 and Figure 3 , in some embodiments, the housing 11 is provided with a light inlet hole 111 that penetrates the housing, and when the camera module 20 is accommodated in the housing 11, the light inlet side of the camera module 20 corresponds to the light inlet hole 111, so as to facilitate the collection of light entering the light inlet hole 111, that is, the object side of the first lens L1 is opposite to the light inlet hole 111. Therefore, the light inlet hole 111 can be circular in shape to adapt to other hole structures of the electronic device 10, which is advantageous to improve the aesthetics of the electronic device 10 compared with the conventional light inlet hole 111 that is square in shape to adapt to the shape of the prism.

[0049] In some embodiments, the camera module 20 satisfies the condition formula: 0.6≤L / TTL≤0.85; wherein L is the optical path of the light in the optical conducting element 27, and TTL is the distance from the object side of the first lens L1 to the imaging surface 22 on the optical axis. For example, L / TTL can be 0.6, 0.71, 0.75, 0.79, 0.82 or 0.85. When the above condition formula is satisfied, the optical path occupied by the optical conducting element 27 in the camera module 20 can be reasonably configured, which is suitable for the telephoto design of the camera module 20, and is also advantageous for the assembly of the camera module 20 while making full use of the optical conducting element 27 to fold the light path.

[0050] In some embodiments, the optical conducting element 27 has a light-transmitting surface 271, a first reflecting surface 272 and a second reflecting surface 273, the light-transmitting surface 271 has an entrance light area 2711 opposite to the fourth lens L4 and an exit light area 2712 opposite to the image sensor 23, the first reflecting surface 272 is inclined to the light-transmitting surface 271 and arranged corresponding to the entrance light area 2711, and the second reflecting surface 273 is inclined to the light-transmitting surface 271 and arranged corresponding to the exit light area 2712, that is, the projection of the first reflecting surface 272 on the light-transmitting surface 271 is at least partially within the range of the entrance light area 2711, and the projection of the second reflecting surface 273 on the light-transmitting surface 271 is at least partially within the range of the exit light area 2712.

[0051] It can be understood that, after being adjusted by the first lens L1 to the fourth lens L4, at least part of the light rays emitted from the fourth lens L4 can enter the optical conducting element 27 from the entrance light area 2711 and be incident on the first reflecting surface 272, the first reflecting surface 272 can reflect at least part of the light rays incident on the first reflecting surface 272 to the light-transmitting surface 271, the light-transmitting surface 271 can reflect at least part of the light rays reflected from the first reflecting surface 272 to the light-transmitting surface 271 to the second reflecting surface 273 in a total reflection manner, and the second reflecting surface 273 can reflect at least part of the light rays reflected from the light-transmitting surface 271 to the second reflecting surface 273 to the exit light area 2712, so that at least part of the light rays are emitted from the optical conducting element 27 from the exit light area 2712 and are incident on the image sensor 23. That is, the light rays incident on the optical conducting element 27 from the entrance light area 2711 can be sequentially reflected by the first reflecting surface 272, the light-transmitting surface 271 and the second reflecting surface 273 and then emitted from the exit light area 2712. The total reflection on the light-transmitting surface 271 can be realized by designing the difference between the refractive index of the optical conducting element 27 and the refractive index of the air medium, and a reflecting film can be arranged on the first reflecting surface 272 and the second reflecting surface 273 to improve the reflectivity of the light rays.

[0052] In some embodiments, the included angles between the first reflecting surface 272 and the light-transmitting surface 271 and between the second reflecting surface 273 and the light-transmitting surface 271 are both greater than or equal to 25° and less than or equal to 35°, for example, 32.5°. In this way, the efficiency and accuracy of the light rays reflected by the first reflecting surface 272, the second reflecting surface 273 and the light-transmitting surface 271 can be improved, so that the optical conducting element 27 can successfully fold the light path by 180°.

[0053] In this embodiment, the optical transmission element 27 can reflect at least a portion of the light three times before projecting it onto the image sensor 23. This makes the optical transmission element 27 suitable for the telephoto design of the camera module 20. Through a periscope design, the size of the camera module 20 in the thickness direction of the electronic device 10 is reduced while being paired with a telephoto-designed camera module 20. For example, it is suitable for a camera module 20 with a magnification of 2x to 4x (equivalent focal length approximately 40mm to 90mm). When the camera module 20 has a higher magnification, the optical transmission element 27 can deflect the light more times to further extend the propagation path of the light in the optical transmission element 27, adapting to the telephoto design of the camera module 20.

[0054] It should be noted that the first reflecting surface 272 and the second reflecting surface 273 can be connected to each other, meaning that the optical transmission element 27 can be approximately prism-shaped. (Reference) Figure 3 As shown, in some embodiments, the optical transmission element 27 may also have a bottom surface 274 connecting the first reflecting surface 272 and the second reflecting surface 273. The bottom surface 274 is opposite to the light-transmitting surface 271, for example, the bottom surface 274 is approximately parallel to the light-transmitting surface 271, and the cross-section of the optical transmission element 27 can be approximately an isosceles trapezoidal shape. Of course, the bottom surface 274 should be positioned to avoid the effective field of view of the first reflecting surface 272 and the second reflecting surface 273, or partially correspond to the stray light portion at the edge of the effective field of view, so as not to affect the normal imaging of the camera module 20. The bottom surface 274 of the optical transmission element 27 can be formed by cutting a prism, or it can be formed directly during the injection molding process. Without affecting the imaging quality of the camera module 20, setting the bottom surface 274, compared to using a prism as the optical transmission element 27, can reduce the size of the optical transmission element 27 in the thickness direction of the electronic device 10, which is beneficial to the miniaturization design of the electronic device 10.

[0055] In some embodiments, the optical transmission element 27 may be made of, but is not limited to, glass or plastic. The refractive index of the optical transmission element 27 may be between 1.5 and 1.9, which can effectively deflect the light path, realize the periscope design of the camera module 20, and also reasonably plan the refractive index difference with the air medium, so that the light reflected from the first reflecting surface 272 can undergo total internal reflection on the light-transmitting surface 271. For example, the optical transmission element 27 may be made of glass with a refractive index of 1.61.

[0056] Of course, in other embodiments, the optical transmission element 27 can also be configured to reflect the light twice before the light exits, the first reflecting surface 272 can reflect the light towards the second reflecting surface 273, that is, the light entering the optical transmission element 27 from the light-in area 2711 can be reflected by the first reflecting surface 272 and the second reflecting surface 273 in sequence before the light exits from the light-out area 2712. In this embodiment, the angle between the first reflecting surface 272 and the light-transmitting surface 271, and the angle between the second reflecting surface 273 and the light-transmitting surface 271 can both be 45°, and the first reflecting surface 272 can be perpendicular to the second reflecting surface 273.

[0057] In some embodiments, the camera module 20 can further include an anti-shake driving element (not shown in the figure), which is configured to drive the focusing lens group 21 to move in a plane perpendicular to the optical axis. The anti-shake driving element can include any combination of magnets, electromagnets, etc. as long as it can drive the focusing lens group 21 to move in a plane perpendicular to the optical axis to achieve the optical anti-shake function of the camera module 20. Figure 3 In the figure, the solid double-headed arrow indicates the direction in which the focusing driving element 24 drives the focusing lens group 21 to move, and the dashed double-headed arrow indicates the direction in which the focusing driving element 24 drives the focusing lens group 21 to move.

[0058] It can be understood that the camera module 20, the focusing driving element 24 and the anti-shake driving element only need to bear the weight of the first lens L1, the second lens L2 and the third lens L3, which is beneficial to reduce the volume and cost of the focusing driving element 24 and the anti-shake driving element. The cooperation of the focal power and surface type of each lens is also beneficial to reduce the focusing driving element 24, further compressing the volume and cost of the focusing driving element 24. At the same time, the focusing lens group 21 is located on the side of the fourth lens L4 away from the optical transmission element 27, and the focusing driving element 24 and the anti-shake driving element are not easily interfered with the optical transmission element 27. The size of the focusing driving element 24 and the anti-shake driving element in the thickness direction of the electronic device 10 also overlaps with the size of the optical filter 26 and the image sensor 23, effectively compressing the volume of the camera module 20 and the size of the camera module 20 in the thickness direction of the electronic device 10, which is beneficial to the miniaturization design of the camera module 20 and the electronic device 10.

[0059] According to the description of the above embodiments, the following more specific embodiments and drawings are proposed for detailed description.

[0060] Please refer to Figure 2 , Figure 2 is a structural schematic diagram of the camera module 20 in the first embodiment. The parameters of the camera module 20 in the first embodiment are given in Table 1 below. Figure 2In the illustrated embodiment, the optical path length between the object side surface and the image side surface of the optical conducting element 27 is equal to the optical path length between the light entrance region 2711 and the light exit region 2712. Figure 3 In the illustrated embodiment, the optical path length between the light entrance region 2711 and the light exit region 2712 is equal, and the same applies to other embodiments. In the first embodiment and other embodiments below, the image side surface of the first lens L1 can be a concave surface.

[0061] Table 1

[0062]

[0063] In the first embodiment, the aspherical coefficients of the object side surface and the image side surface of the second lens L2, the third lens L3 and the fourth lens L4 are given in Table 2 below, where A4-A20 represent the types of aspherical coefficients, A4 represents the fourth aspherical coefficient, A6 represents the sixth aspherical coefficient, A8 represents the eighth aspherical coefficient, and so on. The aspherical coefficient formula is as follows:

[0064]

[0065] where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, K is the conic coefficient, and Ai is the coefficient corresponding to the ith high-order term in the aspherical surface formula.

[0066] Table 2

[0067]

[0068] In the first embodiment, the F-number FNO of the camera module 20 is 3.28, and the maximum field of view FOV is 12.4°. The close focus distance is 80 cm, and the focusing stroke of the focusing lens group 21 is 462 um. The anti-shake angle of the camera module 20 is 0.7°, and the anti-shake stroke of the focusing lens group 21 is ±234 um.

[0069] Please refer to Figure 5 , Figure 5 Figure 2 is a schematic diagram of the structure of the camera module 20 in the second embodiment, and the parameters of the camera module 20 in the second embodiment are given in Table 3 below.

[0070] Table 3

[0071]

[0072] The aspherical coefficients of the object side surface and the image side surface of the second lens L2, the third lens L3 and the fourth lens L4 in the second embodiment are given in Table 4 below, where the meanings of the parameters can be obtained from the description of the first embodiment.

[0073] Table 4

[0074]

[0075]

[0076] In the second embodiment, the F-number of the camera module 20 is FNO=3.5, and the maximum field of view is FOV=12.6°. The close focus distance is 100 cm, and the focusing stroke of the focusing lens group 21 is 400 um. The anti-shake angle of the camera module 20 is 0.7°, and the anti-shake stroke of the focusing lens group 21 is ±244 um.

[0077] Referring to Figure 6 , Figure 6 Fig. 3 is a structural schematic diagram of the camera module 20 in the third embodiment. The parameters of the camera module 20 in the third embodiment are given in Table 5 below.

[0078] Table 5

[0079]

[0080] The aspheric coefficients of the object side and the image side of the second lens L2, the third lens L3 and the fourth lens L4 in the third embodiment are given in Table 6 below, wherein the meanings of the parameters can be obtained from the description of the first embodiment.

[0081] Table 6

[0082]

[0083]

[0084] In the third embodiment, the F-number of the camera module 20 is FNO=3.22, and the maximum field of view is FOV=12.6°. The close focus distance is 90 cm, and the focusing stroke of the focusing lens group 21 is 409 um. The anti-shake angle of the camera module 20 is 0.7°, and the anti-shake stroke of the focusing lens group 21 is ±233 um.

[0085] The above embodiments also satisfy the data in Table 7 below, the meanings of the parameters in Table 7, and the effects that can be obtained by satisfying the data in Table 7 can be obtained from the above description, and will not be described here.

[0086] Table 7

[0087] Conditional expression First embodiment Second embodiment Third embodiment | EFL1 / F4 | 0.601 0.611 0.589 TTL / IMGH 10.36 9.88 10.03 TTL / IMGH 10.36 9.88 10.03 L / TTL 0.759 0.763 0.751 F1 / EFL 0.502 0.47 0.506 R1 / F1 0.498 0.489 0.499

[0088] Referring to Figure 7 , Figure 8 and Figure 9 , Figures 7-9 respectively are the astigmatism curve and the distortion curve of the camera module 20 in the first embodiment, the second embodiment and the third embodiment, respectively, and Figures 7-9It can be seen that the astigmatism and distortion of the camera module 20 in each embodiment of the present application are well controlled, and the camera module 20 has good imaging quality.

[0089] Reference Figure 10 , Figure 10 A structural schematic diagram of an electronic device 10 provided by an embodiment of the present application is shown. The electronic device 10 can include radio frequency (RF) circuit 501, memory 502 including one or more computer readable storage media, input unit 503, display unit 504, sensor 505, audio circuit 506, wireless fidelity (WiFi) module 507, processor 508 including one or more processing cores, and power supply 509, and the like. Those skilled in the art can understand that the electronic device 10 structure shown in the figure does not constitute a limitation on the electronic device 10, and can include more or fewer components than shown, or combine certain components, or different component arrangements. Figure 10 The electronic device 10 structure shown in the figure does not constitute a limitation on the electronic device 10, and can include more or fewer components than shown, or combine certain components, or different component arrangements.

[0090] The radio frequency circuit 501 can be used to receive and send information or signals during a call, in particular, after receiving the downlink information of the base station, it is processed by one or more processors 508; in addition, the data related to the uplink is sent to the base station. Generally, the radio frequency circuit 501 includes, but is not limited to, an antenna, at least one amplifier, a tuner, one or more oscillators, a subscriber identity module (SIM) card, a transceiver, a coupler, a low noise amplifier (LNA), a duplexer, and the like. In addition, the radio frequency circuit 501 can also communicate with the network and other devices through wireless communication. The wireless communication can use any communication standard or protocol, including but not limited to global system for mobile communication (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), long term evolution (LTE), email, short message service (SMS), and the like.

[0091] The memory 502 can be used to store applications and data. The applications stored in the memory 502 include executable code. The applications can constitute various functional modules. The processor 508 executes various functional applications and data processing by running the applications stored in the memory 502. The memory 502 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required by a function (such as a sound playing function, an image playing function, etc.), and the like; and the data storage area can store data created according to the use of the electronic device 10 (such as audio data, a phone book, etc.), and the like. In addition, the memory 502 can include a high-speed random access memory, and can further include a nonvolatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device. Accordingly, the memory 502 can further include a memory controller to provide the processor 508 and the input unit 503 with access to the memory 502.

[0092] The input unit 503 can be used to receive inputted numbers, character information or user feature information (such as a fingerprint), and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control. Specifically, in one specific embodiment, the input unit 503 can include a touch-sensitive surface and other input devices. The touch-sensitive surface, also called a touch display screen or touchpad, can collect user touch operations (such as user operations using a finger, a stylus, or any suitable object or accessory on or near the touch-sensitive surface) on or near it, and drive the corresponding connection device according to the pre-set program. Optionally, the touch-sensitive surface can include two parts of a touch detection device and a touch controller. The touch detection device detects the user's touch position and detects the signal generated by the touch operation, and transmits the signal to the touch controller; the touch controller receives the touch information from the touch detection device, converts it into touch coordinates, and sends it to the processor 508, and can also receive commands from the processor 508 and execute them.

[0093] The display unit 504 can be used to display information input by a user or provided to the user, as well as various graphical user interfaces of the electronic device 10, which can be composed of graphics, text, icons, video, and any combination thereof. The display unit 504 can include a display panel. Optionally, the display panel can be configured in the form of a liquid crystal display (LCD), an organic light-emitting diode (OLED), or the like. Further, a touch-sensitive surface can cover the display panel, which, when a touch operation is detected thereon or in the vicinity thereof, transmits to the processor 508 to determine the type of touch event, and then the processor 508 provides corresponding visual output on the display panel according to the type of touch event. Although in the above description, the touch-sensitive surface and the display panel are implemented as two independent components to realize input and output functions, in some embodiments, the touch-sensitive surface and the display panel can be integrated to realize input and output functions. It can be understood that the display screen 110 can include the input unit 503 and the display unit 504. Figure 10

[0094] The electronic device 10 can further include at least one sensor 505, such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor can include an ambient light sensor that can adjust the brightness of the display panel according to the brightness of ambient light, and a proximity sensor that can turn off the display panel and / or backlight when the electronic device 10 is moved to the ear. As one of the motion sensors, the gravity acceleration sensor can detect the magnitude of acceleration in each direction (generally three axes), and when at rest, can detect the magnitude and direction of gravity, which can be used for applications such as recognizing the posture of the mobile phone (such as switching between landscape and portrait screens, related games, magnetometer posture calibration), vibration recognition related functions (such as pedometers, taps), and the like. As for other sensors that the electronic device 10 can be configured, such as a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, and the like, they will not be described here.

[0095] The audio circuit 506 can provide an audio interface between the user and the electronic device 10 through the speaker and the microphone. The audio circuit 506 can convert received audio data into an electrical signal, transmit it to the speaker, and convert it into a sound signal output by the speaker. On the other hand, the microphone collects sound signals and converts them into electrical signals, which are received by the audio circuit 506 and converted into audio data. After being processed by the processor 508, the audio data is output to the radio frequency circuit 501 to be transmitted to, for example, another electronic device 10, or to the memory 502 for further processing. The audio circuit 506 can also include a headset jack to provide communication between an external headset and the electronic device 10.

[0096] ​Wireless Fidelity (WiFi) is short-range wireless technology that allows an electronic device 10 with WiFi capability to exchange data with other devices at a great speed and in a short range. The WiFi module 507 of the electronic device 10 helps the user to exchange emails, browse web pages and access streaming media, and so on. Although Figure 10 The WiFi module 507 is shown, but it is understood that it does not belong to the essential components of the electronic device 10, and can be omitted without changing the nature of the application.

[0097] The processor 508 is the control center of the electronic device 10, which connects all parts of the electronic device 10 through various interfaces and lines, and performs various functions of the electronic device 10 and processes data by running or executing the application programs stored in the memory 502 and calling the data stored in the memory 502, thereby monitoring the whole electronic device 10. Optionally, the processor 508 can include one or more processing cores; preferably, the processor 508 can integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application programs, etc., and the modem processor mainly processes wireless communication. It is understood that the above-mentioned modem processor can also not be integrated into the processor 508.

[0098] The electronic device 10 further includes a power supply 509 for supplying power to various components. Preferably, the power supply 509 can be logically connected to the processor 508 through a power management system, so as to realize the functions of managing charging, discharging and power consumption management, etc. through the power management system. The power supply 509 can also include one or more than one direct or alternating current power supply, a recharging system, a power failure detection circuit, a power converter or inverter, a power state indicator and any other components.

[0099] Although Figure 10 The electronic device 10 can also include a Bluetooth module and the like, which are not described here in detail. In specific implementation, the above modules can be implemented as independent entities, or can be combined as the same or several entities, and the specific implementation of the above modules can refer to the method embodiments described above, which are not described here in detail.

[0100] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered that they are within the scope of the present disclosure.

[0101] The above embodiments only express several implementation ways of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A camera module, characterized in that, It includes a focusing lens group and a fourth lens disposed on the image side of the focusing lens group. The position of the fourth lens is fixed relative to the imaging surface of the camera module, and the focusing lens group can move relative to the fourth lens along the optical axis. The focusing lens assembly includes, along the optical axis from the object side to the image side, a first lens with positive optical power, a second lens with positive optical power, and a third lens with negative optical power. The object side of the first lens is convex near the optical axis, the object side of the second lens is convex near the optical axis, and the image side is concave near the optical axis. Both the object side and the image side of the third lens are concave near the optical axis. The fourth lens has negative optical power, and its object side is convex near the optical axis, while its image side is concave near the optical axis.

2. The camera module according to claim 1, characterized in that, The camera module satisfies the following condition: 0.5 ≤ |EFL1 / F4| ≤ 0.8; Wherein, EFL1 is the effective focal length of the focusing lens group, and F4 is the effective focal length of the fourth lens.

3. The camera module according to claim 1, characterized in that, The camera module satisfies the following condition: TTL / IMGH≤12; Wherein, TTL is the distance on the optical axis from the object side of the first lens to the imaging surface, and IMGH is the half-image height of the camera module.

4. The camera module according to claim 1, characterized in that, The camera module satisfies the following condition: 8°≤FOV≤20°; Wherein, FOV is the maximum field of view of the camera module.

5. The camera module according to claim 1, characterized in that, The camera module satisfies the following condition: 2.8 ≤ EFL / EPD ≤ 3.8; Wherein, EFL is the effective focal length of the camera module, and EPD is the entrance pupil diameter of the camera module.

6. The camera module according to claim 1, characterized in that, The camera module satisfies the following condition: 0.4 ≤ F1 / EFL ≤ 0.6; Wherein, F1 is the effective focal length of the first lens, and EFL is the effective focal length of the camera module.

7. The camera module according to claim 1, characterized in that, The camera module satisfies the following condition: 0.3≤R1 / F1≤0.7; Wherein, R1 is the radius of curvature of the object side of the first lens at the optical axis, and F1 is the effective focal length of the first lens.

8. The camera module according to any one of claims 1-7, characterized in that, The object-side surface and image-side surface of the first lens are both spherical, while the object-side surface and image-side surface of at least one of the second lens, the third lens, and the fourth lens are both aspherical.

9. The camera module according to any one of claims 1-7, characterized in that, The maximum effective aperture of the first lens, the second lens, the third lens, and the fourth lens decreases sequentially.

10. The camera module according to any one of claims 1-7, characterized in that, The camera module also includes an image sensor disposed at the imaging surface and an optical transmission element disposed between the fourth lens and the image sensor along the optical axis. The optical transmission element is used to transmit light to the image sensor after at least one reflection.

11. The camera module according to claim 10, characterized in that, The camera module satisfies the following condition: 0.6≤L / TTL≤0.85; Where L is the optical path length of the light within the optical transmission element, and TTL is the distance on the optical axis from the object side of the first lens to the imaging surface.

12. The camera module according to claim 10, characterized in that, The optical transmission element is used to transmit light to the image sensor after at least two reflections, so that the axis of the fourth lens is perpendicular to the imaging surface.

13. The camera module according to claim 12, characterized in that, The optical transmission element includes a light-transmitting surface, a first reflective surface, and a second reflective surface. The light-transmitting surface has an incident light area and an exit light area. The incident light area is opposite to the fourth lens, and the exit light area is opposite to the image sensor. The first reflective surface is obliquely opposite to the incident light area, and the second reflective surface is obliquely opposite to the exit light area.

14. The camera module according to claim 12, characterized in that, The optical transmission element includes a light-transmitting surface, a first reflective surface, and a second reflective surface. The light-transmitting surface has an incident light area and an exit light area. The incident light area is opposite to the fourth lens, and the exit light area is opposite to the image sensor. Light rays incident on the optical transmission element from the incident light area can be reflected sequentially by the first reflective surface, the light-transmitting surface, and the second reflective surface before exiting from the exit light area.

15. The camera module according to claim 12, characterized in that, The optical transmission element includes a light-transmitting surface, a first reflective surface, and a second reflective surface. The light-transmitting surface has an incident light area and an exit light area. The incident light area is opposite to the fourth lens, and the exit light area is opposite to the image sensor. Light rays incident on the optical transmission element from the incident light area can be reflected sequentially by the first reflective surface and the second reflective surface and then exit from the exit light area.

16. The camera module according to any one of claims 1-7, characterized in that, The camera module also includes a focus driving element, which is used to drive the focusing lens group to move relative to the imaging surface along the optical axis.

17. The camera module according to any one of claims 1-7, characterized in that, The camera module also includes an image stabilization drive element, which is used to drive the focusing lens group to move in a plane perpendicular to the optical axis.

18. An electronic device, characterized in that, Includes the camera module as described in any one of claims 1-17.

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