Optical system, camera module, and electronic device

Abstract

The present application relates to an optical system (30), a camera module (20), and an electronic device (10). The optical system (30) comprises a lens assembly (31) and a prism (32) arranged between the lens assembly (31) and an imaging plane (33) along an optical path propagation direction. There are three or four lenses having focal power in the lens assembly (31); the lens assembly (31) comprises an object-side lens (311) having positive focal power and an image-side lens (312) having negative focal power; the object-side lens (311) is the lens in the lens assembly (31) closest to the object side, and the object-side surface of the object-side lens (311) is convex near the optical axis; the image-side lens (312) is the lens in the lens assembly (31) closest to the image side. The optical system (30) satisfies: 11≤L / IMGH≤15; and TTL / IMGH≤17.

Description

Optical systems, camera modules and electronic devices

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on December 18, 2024, application number 2024118787797, entitled "Optical System, Camera Module and Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of camera technology, and in particular to an optical system, camera module and electronic device. Background Technology

[0004] The optical system of a periscope camera module typically includes a lens assembly and a prism. The prism guides the light emitted from the lens assembly through one or more reflections to the imaging surface of the optical system. Currently, to accommodate the long back focal length design of the lens assembly, the prism in periscope camera modules is usually quite thick, resulting in an increased size of the camera module in the thickness direction of the electronic device, which is detrimental to the design of thinner and lighter electronic devices. Summary of the Invention

[0005] On one hand, this application provides an optical system including a lens assembly and a prism disposed between the lens assembly and the imaging plane along the optical path propagation direction; the lens assembly has three or four lenses with optical power, the lens assembly includes an object-end lens with positive optical power and an image-end lens with negative optical power, the object-end lens is the lens closest to the object side in the lens assembly, the object side of the object-end lens is convex near the optical axis, and the image-end lens is the lens closest to the image side in the lens assembly;

[0006] The optical system satisfies the following conditions: 11≤L / IMGH≤15; TTL / IMGH≤17;

[0007] Where L is the geometric path of light in the prism, IMGH is half the diagonal length of the effective pixel area on the imaging surface, and TTL is the on-axis distance from the object side of the object lens to the imaging surface.

[0008] On the other hand, this application provides a camera module, including an image sensor and an optical system as described in any of the above embodiments, wherein the image sensor is disposed at the imaging surface of the optical system.

[0009] In another aspect, this application provides an electronic device including the camera module described above. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the disclosed drawings without creative effort.

[0011] Figure 1 is a schematic diagram of the structure of the electronic device with a light-transmitting hole in some embodiments.

[0012] Figure 2 is a schematic diagram of the optical path of the camera module in some embodiments.

[0013] Figure 3 is a schematic diagram of the optical system in the first embodiment.

[0014] Figure 4 is a schematic diagram of the optical system in the second embodiment.

[0015] Figure 5 is a schematic diagram of the optical system in the third embodiment.

[0016] Figure 6 shows the astigmatism curve and distortion curve of the optical system in the first embodiment.

[0017] Figure 7 shows the astigmatism curve and distortion curve of the optical system in the second embodiment.

[0018] Figure 8 shows the astigmatism curve and distortion curve of the optical system in the third embodiment.

[0019] Figure 9 is a schematic diagram of the camera module structure in some embodiments.

[0020] Figure 10 is a schematic diagram of the structure of an electronic device in some embodiments. Detailed Implementation

[0021] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

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

[0023] (1) Via wired connection, such as via Public Switched Telephone Networks (PSTN), Digital Subscriber Line (DSL), digital cable, or direct cable connection;

[0024] (2) Via wireless interfaces, such as cellular networks, wireless local area networks (WLANs), digital television networks such as DVB-H networks, satellite networks, and AM-FM broadcast transmitters.

[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) Satellite phone or cellular phone;

[0027] (2) A personal communications system (PCS) terminal that can combine cellular radio telephone with data processing, fax and data communication capabilities;

[0028] (3) Radio telephone, pager, Internet / intranet access, web browser, notepad, calendar, personal digital assistant (PDA) equipped with a Global Positioning System (GPS) receiver;

[0029] (4) Conventional above-knee and / or palm-sized receivers;

[0030] (5) Conventional knee-mounted and / or handheld wireless telephone transceivers, etc.

[0031] This application provides an optical system, including a lens assembly and a prism disposed between the lens assembly and an imaging plane along the optical path propagation direction; the lens assembly has three or four lenses with optical power, the lens assembly includes an object-end lens with positive optical power and an image-end lens with negative optical power, the object-end lens is the lens closest to the object side in the lens assembly, the object-side surface of the object-end lens is convex near the optical axis, and the image-end lens is the lens closest to the image side in the lens assembly.

[0032] The optical system satisfies the following conditions: 11≤L / IMGH≤15; TTL / IMGH≤17;

[0033] Where L is the geometric path of light in the prism, IMGH is half the diagonal length of the effective pixel area on the imaging surface, and TTL is the on-axis distance from the object side of the object lens to the imaging surface.

[0034] In one embodiment, the image-side surface of the object-end lens is concave near the optical axis, and both the object-side surface and the image-side surface of the image-end lens are concave near the optical axis.

[0035] In one embodiment, the lens assembly further includes a second lens disposed between the object-side lens and the image-side lens, and having a negative optical power, wherein the object-side and image-side surfaces of the second lens are both concave near the optical axis.

[0036] In one embodiment, the lens assembly further includes a second lens and a third lens arranged sequentially between the object-side lens and the image-side lens along the optical path propagation direction. The second lens has positive optical power, and both the object-side and image-side surfaces of the second lens are convex near the optical axis. The third lens has negative optical power, and the object-side surface of the third lens is concave near the optical axis, while the image-side surface is convex near the optical axis.

[0037] In one embodiment, the optical system satisfies the following condition: 8°≤FOV≤12°;

[0038] Wherein, FOV is the maximum field of view of the optical system.

[0039] In one embodiment, the optical system satisfies the following condition: 3 ≤ EFL / EPD ≤ 3.8;

[0040] Wherein, EFL is the effective focal length of the optical system, and EPD is the entrance pupil diameter of the optical system.

[0041] In one embodiment, the optical system satisfies the following condition: 0.3 ≤ F1 / EFL ≤ 0.7;

[0042] Wherein, F1 is the effective focal length of the object lens, and EFL is the effective focal length of the optical system.

[0043] In one embodiment, the optical system satisfies the following condition: 0.5 ≤ R1 / F1 ≤ 0.9;

[0044] Wherein, R1 is the radius of curvature of the object side surface of the object lens at the optical axis, and F1 is the effective focal length of the object lens.

[0045] In one embodiment, the object-side surface and image-side surface of the object-end lens are both spherical, while the object-side surface and image-side surface of the lenses other than the object-end lens in the lens assembly are both aspherical.

[0046] In one embodiment, the prism has a first surface, a second reflecting surface, and a third reflecting surface. The lens assembly and the imaging surface are both located on one side of the first surface and opposite to the first surface. The second reflecting surface is inclined to the first surface and opposite to the lens assembly in the axial direction of the lens assembly. The third reflecting surface is inclined to the first surface and opposite to the imaging surface in the perpendicular direction of the imaging surface. At least a portion of the light emitted from the lens assembly can enter the prism from the first surface and, after being reflected by at least the second reflecting surface and the third reflecting surface, exit from the first surface onto the imaging surface.

[0047] In one embodiment, the prism further has a fourth reflecting surface opposite to the first surface and located between the second reflecting surface and the third reflecting surface, so that light rays incident on the prism from the first surface can be reflected sequentially by the second reflecting surface, the first surface, the fourth reflecting surface, the first surface, the fourth reflecting surface, the first surface, the third reflecting surface, and then exit from the first surface.

[0048] In one embodiment, the lenses in the lens assembly, except for the image-end lens, are relatively fixed, and the image-end lens is axially movable among the other lenses in the lens assembly and the prism.

[0049] In one embodiment, the optical system further includes an aperture stop disposed on the object side of the object-end lens.

[0050] In one embodiment, the optical system further includes a filter disposed between the prism and the imaging surface.

[0051] A camera module includes an image sensor and an optical system as described in any of the above embodiments, wherein the image sensor is disposed at the imaging surface of the optical system.

[0052] In one embodiment, the camera module further includes a stabilization drive mechanism for driving the image sensor to move on a plane parallel to the imaging surface to achieve optical image stabilization.

[0053] A camera module includes an optical system and an image sensor. The optical system includes a lens assembly and a prism. The prism has a first surface, a second reflective surface, and a third reflective surface. The lens assembly and the image sensor are located on one side of the first surface and opposite to the first surface. The second reflective surface is inclined to the first surface and opposite to the lens assembly in the axial direction of the lens assembly. The third reflective surface is inclined to the first surface and opposite to the image sensor in the perpendicular direction of the imaging surface of the lens assembly.

[0054] At least a portion of the light emitted from the lens assembly can enter the prism from the first surface, and after being reflected by at least the second and third reflecting surfaces, exit from the first surface onto the image sensor.

[0055] In one embodiment, the prism further has a fourth reflecting surface opposite to the first surface and located between the second reflecting surface and the third reflecting surface, so that light rays incident on the prism from the first surface can be reflected sequentially by the second reflecting surface, the first surface, the fourth reflecting surface, the first surface, the fourth reflecting surface, the first surface, the third reflecting surface, and then exit from the first surface.

[0056] In one embodiment, the lens assembly includes multiple lenses arranged coaxially, wherein the lens closest to the image side is the image-end lens, and the lenses in the lens assembly other than the image-end lens are fixed relative to the image sensor, and the image-end lens is axially movable among the other lenses in the lens assembly and the prism.

[0057] In one embodiment, the optical system satisfies the following conditions: 11 ≤ L / IMGH ≤ 15; TTL / IMGH ≤ 17;

[0058] Where L is the geometric path of light in the prism, IMGH is half the diagonal length of the effective pixel area on the imaging surface of the optical system, and TTL is the on-axis distance from the object side of the lens closest to the object end in the lens assembly to the imaging surface.

[0059] An electronic device includes a camera module as described in any of the above embodiments.

[0060] Please refer to Figures 1 and 2. Figure 1 is a schematic diagram of the structure of the electronic device 10 in some embodiments, and Figure 2 is a schematic diagram of the structure of the camera module 20 in some embodiments. The camera module 20 provided in this application includes, but is not limited to, any applicable electronic device 10 such as smartphones, tablets, e-readers, and wearable devices. The camera module 20 can collect image information from the object side, so that the electronic device 10 has the functions of image capture and shooting. The embodiments of this application use smartphones as an example for description.

[0061] In some embodiments, the electronic device 10 further includes a housing 11, within which a camera module 20 is disposed. The housing 11 may include a mid-frame and a rear cover. The mid-frame may be generally rectangular, and the rear cover covers one side of the mid-frame. The camera module 20 is located within the receiving space formed by the rear cover and the mid-frame, and is exposed to the rear cover to collect light from the rear cover side of the electronic device 10. The electronic device 10 may also include a display screen, which covers the side of the mid-frame facing away from the rear cover. When the camera module 20 is used to collect light from the rear cover side of the electronic device 10, the camera module 20 may be a rear-facing camera. In other embodiments, the camera module 20 may also be a front-facing camera, in which case the camera module 20 may be exposed to the side where the display screen is located and used to collect light from that side. The electronic device 10 may also include any other suitable components to achieve richer functionality, which will not be elaborated upon in this application.

[0062] In some embodiments, the camera module 20 includes an optical system 30 and an image sensor 21. The image sensor 21 includes, but is not limited to, a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). The optical system 30 has an imaging surface 33. The image sensor 21 is disposed at the imaging surface 33 of the optical system 30. For example, the imaging surface 33 may at least partially overlap with the photosensitive surface of the image sensor 21. The light collected by the camera module 20 is regulated and transmitted by the optical system 30 and then projected onto the imaging surface 33 to form an image on the image sensor 21.

[0063] In some embodiments, the optical system 30 includes a lens assembly 31 and a prism 32 disposed between the lens assembly 31 and the imaging surface 33 along the light path propagation direction. The lens assembly 31 includes one or more lenses with optical power. The lens assembly 31 can be opposite to the light-transmitting hole 111 of the housing 11 and collect ambient light through the light-transmitting hole 111. The light passes through the adjustment of the lens assembly 31 and the conduction of the prism 32 in sequence and is projected onto the image sensor 21. The axis of the lens assembly 31 can be parallel to the thickness direction of the electronic device 10, so the thickness direction of the camera module 20 corresponds to the thickness direction of the electronic device 10.

[0064] Furthermore, in some embodiments, the lens assembly 31 has three or four lenses with optical power. The lens assembly 31 includes an object-end lens 311 with positive optical power and an image-end lens 312 with negative optical power. The object-end lens 311 is the lens closest to the object side in the lens assembly 31, and the object side of the object-end lens 311 is convex near the optical axis. The image-end lens 312 is the lens closest to the image side in the lens assembly 31. The optical system 30 satisfies the following conditions: 11≤L / IMGH≤15; TTL / IMGH≤17; where L is the geometric path of light in the prism 32. For example, the prism 32 may have an incident light area 3211 and an exit light area 3212. At least part of the light emitted from the lens assembly 31 can enter the prism 32 from the incident light area 3211 and exit from the exit light area 3212 after being transmitted through the prism 32. Then L is the geometric path of light between the incident light area 3211 and the exit light area 3212. IMGH is half the diagonal length of the effective pixel area on the imaging surface 33, which is the half image height of the optical system 30. TTL is the axial distance from the object side of the object lens 311 to the imaging surface 33, which is the total optical length of the optical system 30.

[0065] The aforementioned optical system 30, with its positive optical power of the object-end lens 311 and its convex shape near the optical axis, facilitates control of the light entering the optical system 30, balances aberrations, and improves imaging quality. Combined with the negative optical power of the image-end lens 312, it increases the back focal length of the optical system 30, enabling a telephoto design. Simultaneously, the optical system 30 satisfies 11≤L / IMGH≤15 and TTL / IMGH≤17. This increases the geometric path of light in the prism 32 to achieve a long back focal length while simultaneously reducing the overall optical length of the optical system 30, balancing imaging quality. The combined optical power and surface design of the object-end lens 311 and image-end lens 312 allow the optical system 30 to balance a long back focal length, a smaller thickness, and good imaging quality. Therefore, when the camera module 20 is applied to the electronic device 10, it satisfies both the telephoto design and good imaging quality while also reducing the thickness of the electronic device 10, contributing to a thinner and lighter design. Using only three or four lenses with optical power in the optical system 30 achieves a telephoto design and good imaging quality. It also helps to reduce the on-axis dimensions of the optical system 30, simplify the parts of the optical system 30, and reduce the manufacturing cost of the optical system 30.

[0066] In some embodiments, the image-side surface of the object lens 311 is concave near the optical axis, and both the object-side surface and the image-side surface of the image lens 312 are concave near the optical axis. The combination of the optical power and surface design of the object lens 311 and the image lens 312 can reasonably control the direction of light and increase the back focal length of the optical system 30, so as to take into account both telephoto design and good imaging quality.

[0067] Referring to Figures 2 and 3, in some embodiments, the lens assembly 31 further includes a second lens 313 and a third lens 314 sequentially arranged along the optical path propagation direction between the object lens 311 and the image lens 312. The second lens 313 has positive optical power, and both its object-side and image-side surfaces are convex near the optical axis. The third lens 314 has negative optical power, and its object-side surface is concave near the optical axis, while its image-side surface is convex near the optical axis. The arrangement of four lenses with optical power in the lens assembly 31, along with the matching of the optical power and surface shape of the second lens 313 and the object lens 311, facilitates reasonable control of the light path, allowing the light collected by the object lens 311 to transition smoothly. This helps suppress various aberrations in the lens assembly 31 and improves the imaging quality of the optical system 30. Furthermore, the optical power and surface shape design of the third lens 314, in conjunction with the other three lenses, helps balance various aberrations while achieving a telephoto design, thus balancing telephoto capability with good imaging quality.

[0068] Referring to Figure 4, in some embodiments, the lens assembly 31 contains three lenses with optical power. The lens assembly 31 also includes a second lens 313 with negative optical power, located between the object lens 311 and the image lens 312. The object-side and image-side surfaces of the second lens 313 are concave near the optical axis. Therefore, the optical power and surface design of the second lens 313 can form a good match with the object lens 311 and the image lens 312, creating a reasonable transition of light between them. This allows for a long back focal length design and good image quality with only three lenses, which helps to reduce the on-axis dimensions of the optical system 30 and thus reduce the thickness of the electronic device 10.

[0069] In some embodiments, the optical system 30 satisfies the condition: 8°≤FOV≤12°; where FOV is the maximum field of view of the optical system 30. When the above condition is satisfied, combined with 11≤L / IMGH≤15; TTL / IMGH≤17, it not only meets the light-gathering requirements of the optical system 30 but also helps to suppress the generation of aberrations such as distortion, and is beneficial to balancing telephoto design, small on-axis size and good image quality.

[0070] In some embodiments, the optical system 30 satisfies the condition: 3 ≤ EFL / EPD ≤ 3.8; where EFL is the effective focal length of the optical system 30, and EPD is the entrance pupil diameter of the optical system 30. When the above condition is satisfied, the aperture number of the optical system 30 can be reasonably configured, thereby achieving both a telephoto design and a large aperture design, increasing the amount of light entering the optical system 30, and thus improving the imaging brightness and imaging quality of the optical system 30.

[0071] In some embodiments, the optical system 30 satisfies the condition: 0.3 ≤ F1 / EFL ≤ 0.7; where F1 is the effective focal length of the object lens 311 and EFL is the effective focal length of the optical system 30. Satisfying this condition allows for a reasonable configuration of the ratio between the effective focal length of the object lens 311 and the effective focal length of the optical system 30, thus reasonably balancing the deflection burden of the object lens 311 within the optical system 30. This not only ensures that the object lens 311 has sufficient deflection force to effectively deflect imaging light rays with a large field of view, suppressing aberrations in the optical system 30 and improving the imaging quality of the optical system 30, but also facilitates the excessive concentration of optical power in the object lens 311, reducing its aberration sensitivity and tolerance sensitivity, and providing more relaxed tolerance conditions for the molding and assembly processes of the object lens 311.

[0072] In some embodiments, the optical system 30 satisfies the condition: 0.5 ≤ R1 / F1 ≤ 0.9; where R1 is the radius of curvature of the object-side surface of the object lens 311 at the optical axis, and F1 is the effective focal length of the object lens 311. When the above condition is satisfied, the ratio of the radius of curvature of the object-side surface of the object lens 311 to the effective focal length can be rationally configured, thereby rationally controlling the light path. This is beneficial for suppressing aberrations such as spherical aberration and chromatic aberration generated by the object lens 311, and also helps to avoid strong total internal reflection ghosting caused by excessive deflection angle in the object lens 311, thus improving the imaging quality of the optical system 30.

[0073] In some embodiments, the object-side and image-side surfaces of the object lens 311 are both spherical, while the object-side and image-side surfaces of at least one lens in the lens assembly 31 are both aspherical. For example, the object-side and image-side surfaces of all lenses in the lens assembly 31 other than the object lens 311 are aspherical. This arrangement balances design difficulty, manufacturing cost, and design flexibility. The aspherical surface effectively corrects aberrations such as spherical aberration, thus improving the imaging quality of the optical system 30. It is understood that when a surface of a lens is spherical, its surface shape is the same near the optical axis and at the circumference. When a surface of a lens is aspherical, its surface shape near the optical axis and at the circumference can be the same or different. The surface shape at the circumference can be designed according to imaging requirements. This application does not limit the surface shape of each aspherical lens at the circumference.

[0074] In some embodiments, the optical system 30 may also be provided with an aperture stop 34, which may be disposed on the object side of the object lens 311, for example, on the object side of the object lens 311. In other embodiments, the aperture stop 34 may also be disposed between any two lenses. In some embodiments, the camera module 20 may also include a filter 23 disposed between the prism 32 and the imaging surface 33. The filter 23 may include, but is not limited to, an infrared cut-off filter. The filter 23 is used to filter out interference light and prevent interference light from reaching the imaging surface 33 and affecting normal imaging. Of course, the filter 23 may also be replaced by a flat protective glass or omitted. When the filter 23 is omitted, the axial distance between the light-emitting area 3212 of the prism 32 and the imaging surface 33 remains unchanged.

[0075] In some embodiments, the lenses and prisms 32 in the optical system 30 can all be made of glass or all of plastic. Using plastic lenses reduces the weight of the optical system 30 and lowers production costs, allowing for a slimmer and lighter design of the camera module 20 in conjunction with its smaller size. Using glass lenses, on the other hand, gives the optical system 30 excellent optical performance and high temperature resistance. It should be noted that the lenses in the camera module 20 can also be made of any combination of glass and plastic, and do not necessarily have to be made entirely of glass or entirely of plastic.

[0076] Based on the descriptions of the above embodiments, more specific embodiments and accompanying drawings are provided below for detailed explanation.

[0077] Please refer to Figure 3, which is a schematic diagram of the structure of the optical system 30 in the first embodiment. In the first embodiment, the lens assembly 31 includes four lenses with optical power. The parameters of the optical system 30 in the first embodiment are given in Table 1 below.

[0078] Table 1

[0079] In the first embodiment, the object-side and image-side surfaces of the second lens 313, the third lens 314, and the image-end lens 312 are all aspherical surfaces, and the aspherical coefficients are given in Table 2 below, where A4-A20 represent the types of aspherical coefficients, A4 represents a fourth-order aspherical coefficient, A6 represents a sixth-order aspherical coefficient, A8 represents an eighth-order aspherical coefficient, and so on. The formula for the aspherical coefficient is as follows:

[0080] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, K is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula.

[0081] Table 2

[0082] Please refer to Figure 4 again. Figure 4 is a schematic diagram of the structure of the optical system 30 in the second embodiment. In the second embodiment, the lens assembly 31 has three lenses with optical power. The parameters of the optical system 30 in the second embodiment are given in Table 3 below.

[0083] Table 3

[0084] In the second embodiment, the object-side surface and image-side surface of the second lens 313 and the image-end lens 312 are both aspherical, and the aspherical coefficients are given in Table 4 below, wherein the meaning of each parameter can be obtained from the description in the first embodiment.

[0085] Table 4

[0086] Please refer to Figure 5, which is a schematic diagram of the structure of the optical system 30 in the third embodiment. The lens assembly 31 in the third embodiment has four lenses with optical power. The parameters of the optical system 30 in the third embodiment are given in Table 5 below.

[0087] Table 5

[0088] In the third embodiment, the object-side surface and image-side surface of the second lens 313, the third lens 314, and the image-end lens 312 are all aspherical, and the aspherical coefficients are given in Table 6 below, wherein the meaning of each parameter can be obtained from the description in the first embodiment.

[0089] Table 6

[0090] Please refer to Figures 6, 7 and 8. Figures 6-8 are astigmatism curves and distortion curves of the optical system 30 in the first embodiment, the second embodiment and the third embodiment, respectively. As can be seen from Figures 6-8, the astigmatism and distortion of the optical system 30 in each embodiment of this application can be effectively corrected, thereby achieving good imaging quality while realizing the telephoto design.

[0091] It should be noted that in the embodiments shown in Figures 2-5, in order to facilitate the illustration of the light path, the prism 32 is replaced by an equivalent flat glass, which should not be construed as a limitation on the structure of the prism 32. In this application, the camera module 20 can adopt a periscope design, so the prism 32 can transmit light through one or more reflections, thereby further reducing the space occupied by the camera module 20 in the thickness direction of the electronic device 10, which is conducive to the thin design of the electronic device 10.

[0092] Referring to Figure 9, in some embodiments, the prism 32 has a first surface 321, a second reflecting surface 322, and a third reflecting surface 323. The lens assembly 31 and the imaging surface 33 are located on the same side of the first surface 321 and are both opposite to the first surface 321. The light-incident region 3211 of the prism 32 is formed in the region of the first surface 321 opposite to the lens assembly 31, and the light-exit region 3212 is formed in the region of the first surface 321 opposite to the lens assembly 31. The second reflecting surface 322 is inclined to the first surface 321 and is opposite to the lens assembly 31 in the axial direction of the lens assembly 31. The third reflecting surface 323 is inclined to the first surface 321 and is opposite to the image sensor 21 in the perpendicular direction of the imaging surface 33. At least a portion of the light emitted from the lens assembly 31 can enter the prism 32 from the light-incident area 3211 of the first surface 321, and after being reflected by at least the second reflecting surface 322 and the third reflecting surface 323, exit the prism 32 from the light-outceasing area 3212 of the first surface 321 and then reach the image sensor 21. The reflection of light by the prism 32 can achieve the effect of folding the light path, thereby transferring part of the light path from the thickness direction of the electronic device 10 to the length direction, which is beneficial to reducing the size of the telephoto-designed camera module 20 in the thickness direction of the electronic device 10.

[0093] Understandably, since light is reflected at least twice by the second reflecting surface 322 and the third reflecting surface 323 in the prism 32, the prism 32 is used to guide the light to the image sensor 21 after at least two reflections, so that the axis of the lens assembly 31 is perpendicular to the imaging surface 33. That is, the prism 32 can deflect the light path by 180°. With this configuration, the prism 32 can fold the light path through multiple reflections, increasing the geometric path of light within the prism 32 to achieve a telephoto design while effectively compressing the volume of the prism 32. Furthermore, when the axis of the lens assembly 31 is parallel to the thickness direction of the electronic device 10, the dimensions of the image sensor 21 and the filter 23 in the thickness direction of the electronic device 10 at least partially coincide with those of the lens assembly 31, which can effectively compress the size of the camera module 20 in the thickness direction of the electronic device 10.

[0094] Referring to Figures 1 and 9, in some embodiments, a light-transmitting hole 111 is provided on the housing 11. When the camera module 20 is housed within the housing 11, the light-incident side of the camera module 20 corresponds to the light-transmitting hole 111 to facilitate the collection of light entering the light-transmitting hole 111. In other words, the lens assembly 31 is opposite to the light-transmitting hole 111. Therefore, the light-transmitting hole 111 can be adapted to the shape of the lens in the lens assembly 31 by being circular, thus matching the other hole structures of the electronic device 10. Compared to the traditional method where a prism is opposite to the light-transmitting hole, requiring a square light-transmitting hole to adapt to the shape of the prism, this improves the overall appearance consistency of the electronic device 10. Furthermore, compared to traditional camera modules where the prism is located on the object side of the lens assembly, requiring the lens in the lens assembly to be chamfered to accommodate the light guiding of the prism, the lens assembly 31 in this embodiment, as the object-side light-receiving component of the camera module 20, does not require lens chamfering. This also helps to increase the aperture of the camera module 20, improve the light-receiving effect of the camera module 20, and thus improve the imaging brightness and imaging quality of the camera module 20.

[0095] It is understandable that the angles between the second and third reflecting surfaces 322 and 323 and the first surface 321, as well as the different lengths of the prism 32, will result in different numbers of reflections of light within the prism 32. For example, the smaller the acute angle between the second and third reflecting surfaces 322 and the first surface 321, and the larger the length of the prism 32, the more times the light can be reflected within the prism 32, and the longer the geometric path of the light within the prism 32. This improves the flexibility of the optical path design of the prism 32 and the camera module 20, adapting to different telephoto design requirements. For instance, in some embodiments, light incident on the prism 32 from the light-incident region 3211 can be reflected sequentially by the second and third reflecting surfaces 322 and then exit, resulting in two reflections within the prism 32. In other embodiments, light rays incident on the prism 32 from the light incident region 3211 can be reflected sequentially by the second reflecting surface 322, the first surface 321 and the third reflecting surface 323 before exiting. The light rays undergo two reflections within the prism 32, which can achieve a longer focal length and a greater magnification.

[0096] Furthermore, referring to FIG9, in some embodiments, the prism 32 also has a fourth reflecting surface 324 opposite to the first surface 321 and located between the second reflecting surface 322 and the third reflecting surface 323. Light rays incident on the prism 32 from the first surface 321 can be reflected sequentially by the second reflecting surface 322, the first surface 321, the fourth reflecting surface 324, the first surface 321, the fourth reflecting surface 324, the first surface 321, and the third reflecting surface 323 before exiting from the first surface 321. For example, at least a portion of the light rays incident from the first surface 321 can reach the second reflecting surface 322, and then be reflected by the second reflecting surface 322 back onto the first surface 321. The light is then reflected by the first surface 321 onto the fourth reflecting surface 324, then back onto the first surface 321, and again reflected by the first surface 321 back onto the fourth reflecting surface 324. Finally, the light is reflected by the fourth reflecting surface 324 back onto the first surface 321, reflected by the first surface 321 onto the third reflecting surface 323, and exits from the first surface 321. In other words, in this embodiment, the light can undergo seven reflections within the prism 32, effectively increasing the geometric path length of the light within the prism 32. This allows the camera module 20 to achieve a longer focal length design, such as an optical zoom of 10x or more, meeting the requirements of a telephoto design. This also helps to reduce the size of the prism 32 in the axial direction of the lens assembly 31, thereby helping to reduce the size of the camera module 20 in the thickness direction of the electronic device 10. Combined with the design of 11≤L / IMGH≤15 and TTL / IMGH≤17 in the optical system 30, it can take into account both small thickness size and long focal length design.

[0097] In some embodiments, the lenses in the lens assembly 31, except for the image-end lens 312, are relatively fixed, while the image-end lens 312 is axially movable among the other lenses in the lens assembly 31 and the prism 32. The camera module 20 may also include a focusing drive mechanism 22, which includes, but is not limited to, a voice coil motor. The other lenses in the lens assembly 31, except for the image-end lens 312, can be fixed to the structural components of the focusing drive mechanism 22, while the image-end lens 312 can be fixed to a movable component inside the focusing drive mechanism 22. The focusing drive mechanism 22 is used to drive the image-end lens 312 to move axially relative to the other lenses and the prism 32. Therefore, by driving the image-end lens 312 to move along the axial direction, the internal focusing function of the camera module 20 can be achieved. This effectively shortens the focusing stroke of the image-end lens 312 within the same object distance range while achieving a telephoto design, reducing the stroke requirements of the camera module 20 on the focusing drive mechanism 22. The design of only driving the image-end lens 312 also helps to reduce the load requirements of the camera module 20 on the focusing drive mechanism 22. This helps to reduce the space occupied by the focusing drive mechanism 22, thereby reducing the size of the camera module 20, facilitating miniaturization, and making it easier to assemble the camera module 20 in the electronic device 10. In addition, the setting of the image-end lens 312 moving relative to other lenses, combined with the optical power and surface shape design of each lens in the lens assembly 31, can effectively correct aberrations under different object distances while reducing the focusing stroke, and reasonably constrain the optical path trend under different object distances, so that the camera module 20 can have good image quality under different object distances.

[0098] In some embodiments, the camera module 20 may further include an image stabilization drive mechanism (not shown). This mechanism includes, but is not limited to, a voice coil motor, a cantilever stabilization mechanism, or a shape memory metal stabilization mechanism. The image stabilization drive mechanism drives the image sensor 21 to move on a plane parallel to the imaging plane 33 to achieve optical image stabilization of the camera module 20. It is understood that in the above-described camera module 20, the focusing drive mechanism 22 and the image stabilization drive mechanism only need to support the weight of the image-end lens 312 and the image sensor 21, respectively. This helps reduce the size and cost of the focusing drive mechanism 22 and the image stabilization drive components. The optical power and surface shape matching of each lens also helps reduce the focusing stroke, further compressing the size and cost of the focusing drive mechanism 22. Simultaneously, the focusing drive mechanism 22 and the image stabilization drive mechanism drive different components respectively, and their operation is relatively independent, making mutual interference less likely and improving the operational stability of the camera module 20. The focusing drive mechanism 22 and the image stabilization drive mechanism overlap at least partially in the thickness direction of the electronic device 10, which is beneficial to effectively compressing the thickness of the camera module 20 and to the thinner design of the camera module 20 and the electronic device 10.

[0099] Referring to FIG10, FIG10 is a schematic diagram of the structure of an electronic device 10 provided in an embodiment of this application. The electronic device 10 may include a radio frequency (RF) circuit 501, a memory 502 including one or more computer-readable storage media, an input unit 503, a display unit 504, a sensor 505, an audio circuit 506, a wireless Fidelity (WiFi) module 507, a processor 508 including one or more processing cores, and a power supply 509, etc. Those skilled in the art will understand that the structure of the electronic device 10 shown in FIG10 does not constitute a limitation on the electronic device 10, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0100] The radio frequency (RF) circuit 501 can be used to send and receive information, or to receive and send signals during a call. Specifically, it receives downlink information from the base station and hands it over to one or more processors 508 for processing; additionally, it sends uplink data to the base station. Typically, the RF 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, etc. Furthermore, the RF circuit 501 can also communicate wirelessly with networks and other devices. This wireless communication can use any communication standard or protocol, including but not limited to GSM, GPRS, CDMA, WCDMA, LTE, email, and SMS.

[0101] Memory 502 can be used to store applications and data. The applications stored in memory 502 contain executable code. Applications can be composed of various functional modules. Processor 508 executes various functional applications and data processing by running the applications stored in memory 502. Memory 502 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, applications required for at least one function (such as sound playback, image playback, etc.), etc.; the data storage area may store data created based on the use of electronic device 10 (such as audio data, phonebook, etc.). Furthermore, memory 502 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, memory 502 may also include a memory controller to provide access to memory 502 for processor 508 and input unit 503.

[0102] Input unit 503 can be used to receive input numbers, character information, or user characteristic information (such as fingerprints), and to generate keyboard, mouse, joystick, optical, or trackball signal inputs related to user settings and function control. Specifically, in one embodiment, input unit 503 may include a touch-sensitive surface and other input devices. The touch-sensitive surface, also known as a touch display or touchpad, can collect touch operations performed by the user on or near it (such as operations performed by the user using a finger, stylus, or any suitable object or accessory on or near the touch-sensitive surface), and drive corresponding connection devices according to a pre-set program. Optionally, the touch-sensitive surface may include two parts: a touch detection device and a touch controller. The touch detection device detects the user's touch orientation and the signal generated by the touch operation, transmitting the signal to the touch controller; the touch controller receives touch information from the touch detection device, converts it into touch point coordinates, sends it to the processor 508, and can receive and execute commands from the processor 508.

[0103] Display unit 504 can be used to display information input by the user or information provided to the user, as well as various graphical user interfaces of electronic device 10. These graphical user interfaces can be composed of graphics, text, icons, video, and any combination thereof. Display unit 504 may include a display panel. Optionally, the display panel can be configured in the form of a liquid crystal display (LCD), organic light-emitting diode (OLED), or the like. Further, a touch-sensitive surface can cover the display panel. When the touch-sensitive surface detects a touch operation on or near it, it transmits the information to processor 508 to determine the type of touch event. Subsequently, processor 508 provides corresponding visual output on the display panel according to the type of touch event. Although in FIG. 10, the touch-sensitive surface and the display panel are implemented as two separate 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.

[0104] The electronic device 10 may also include at least one sensor 505, such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor may include an ambient light sensor and a proximity sensor. The ambient light sensor can adjust the brightness of the display panel according to the ambient light level, and the proximity sensor can turn off the display panel and / or backlight when the electronic device 10 is moved to the ear. As a type of motion sensor, a gravity acceleration sensor can detect the magnitude of acceleration in various directions (generally three axes). When stationary, it can detect the magnitude and direction of gravity and can be used for applications that recognize the phone's posture (such as landscape / portrait switching, related games, magnetometer posture calibration), vibration recognition-related functions (such as pedometer, tapping), etc. Other sensors that may be configured in the electronic device 10, such as gyroscopes, barometers, hygrometers, thermometers, and infrared sensors, will not be described in detail here.

[0105] Audio circuit 506 provides an audio interface between the user and electronic device 10 via a speaker and microphone. Audio circuit 506 converts received audio data into electrical signals, transmits them to the speaker, and the speaker outputs them as sound signals. Conversely, the microphone converts collected sound signals into electrical signals, which are then received by audio circuit 506, converted back into audio data, and processed by processor 508. The audio data is then transmitted via radio frequency circuit 501 to, for example, another electronic device 10, or output to memory 502 for further processing. Audio circuit 506 may also include a headphone jack to facilitate communication between peripheral headphones and electronic device 10.

[0106] Wi-Fi is a short-range wireless transmission technology. Electronic device 10, through Wi-Fi module 507, can help users send and receive emails, browse web pages, and access streaming media, providing users with wireless broadband internet access. Although Figure 10 shows Wi-Fi module 507, it is understood that it is not an essential component of electronic device 10 and can be omitted as needed without changing the essence of the invention.

[0107] The processor 508 is the control center of the electronic device 10. It connects various parts of the electronic device 10 via various interfaces and lines. By running or executing applications stored in the memory 502 and calling data stored in the memory 502, it performs various functions and processes data of the electronic device 10, thereby providing overall monitoring of the electronic device 10. Optionally, the processor 508 may include one or more processing cores; preferably, the processor 508 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into the processor 508.

[0108] The electronic device 10 also includes a power supply 509 that supplies power to the various components. Preferably, the power supply 509 can be logically connected to the processor 508 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply 509 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0109] Although not shown in Figure 10, the electronic device 10 may also include a Bluetooth module, etc., which will not be described in detail here. In specific implementation, the above modules can be implemented as independent entities, or they can be arbitrarily combined and implemented as the same or several entities. For the specific implementation of the above modules, please refer to the previous method embodiments, which will not be described in detail here.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

An optical system includes a lens assembly and a prism disposed between the lens assembly and an imaging plane along the optical path propagation direction; the lens assembly has three or four lenses with optical power, the lens assembly includes an object-end lens with positive optical power and an image-end lens with negative optical power, the object-end lens is the lens closest to the object side of the lens assembly, the object-side surface of the object-end lens is convex near the optical axis, and the image-end lens is the lens closest to the image side of the lens assembly. The optical system satisfies the following condition: 11≤L / IMGH≤15; TTL / IMGH≤17; wherein L is the geometric path length of light in the prism, IMGH is half the diagonal length of the effective pixel area on the imaging surface, and TTL is the on-axis distance from the object side of the object lens to the imaging surface. The optical system according to claim 1, wherein The image-side surface of the object-end lens is concave near the optical axis, and both the object-side surface and the image-side surface of the image-end lens are concave near the optical axis. The optical system according to claim 1, wherein The lens assembly further includes a second lens disposed between the object-side lens and the image-side lens, and having a negative optical power. The object-side and image-side surfaces of the second lens are both concave near the optical axis. The optical system according to claim 1, wherein The lens assembly further includes a second lens and a third lens arranged sequentially between the object-side lens and the image-side lens along the optical path propagation direction. The second lens has positive optical power, and both the object-side and image-side surfaces of the second lens are convex near the optical axis. The third lens has negative optical power, and both the object-side and image-side surfaces of the third lens are concave near the optical axis and convex near the optical axis. The optical system according to claim 1, wherein The optical system satisfies the following condition: 8°≤FOV≤12°; Wherein, FOV is the maximum field of view of the optical system. The optical system according to claim 1, wherein The optical system satisfies the following condition: 3 ≤ EFL / EPD ≤ 3.8; Wherein, EFL is the effective focal length of the optical system, and EPD is the entrance pupil diameter of the optical system. The optical system according to claim 1, wherein The optical system satisfies the following condition: 0.3≤F1 / EFL≤0.7; Wherein, F1 is the effective focal length of the object lens, and EFL is the effective focal length of the optical system. The optical system according to claim 1, wherein The optical system satisfies the following condition: 0.5≤R1 / F1≤0.9; Wherein, R1 is the radius of curvature of the object side surface of the object lens at the optical axis, and F1 is the effective focal length of the object lens. The optical system according to claim 1, wherein The object-side and image-side surfaces of the object-end lens are both spherical, while the object-side and image-side surfaces of the lenses other than the object-end lens in the lens assembly are both aspherical. The optical system according to any one of claims 1 to 9, wherein The prism has a first surface, a second reflecting surface, and a third reflecting surface. The lens assembly and the imaging surface are both located on one side of the first surface and opposite to the first surface. The second reflecting surface is inclined to the first surface and is opposite to the lens assembly in the axial direction of the lens assembly. The third reflecting surface is inclined to the first surface and is opposite to the imaging surface in the perpendicular direction of the imaging surface. At least a portion of the light emitted from the lens assembly can enter the prism from the first surface and, after being reflected by at least the second reflecting surface and the third reflecting surface, exit from the first surface onto the imaging surface. The optical system according to claim 10, wherein The prism also has a fourth reflecting surface opposite to the first surface and located between the second reflecting surface and the third reflecting surface. Light rays incident on the prism from the first surface can be reflected sequentially by the second reflecting surface, the first surface, the fourth reflecting surface, the first surface, the fourth reflecting surface, the first surface, the first surface, and the third reflecting surface before exiting from the first surface. The optical system according to any one of claims 1 to 9, wherein In the lens assembly, all lenses except the image-end lens are relatively fixed, while the image-end lens is axially movable among the other lenses in the lens assembly and the prism. The optical system according to any one of claims 1 to 9, wherein The optical system also includes an aperture stop, which is disposed on the object side of the object-end lens. The optical system according to any one of claims 1 to 9, wherein The optical system also includes a filter disposed between the prism and the imaging surface. A camera module includes an image sensor and an optical system as described in any one of claims 1-14, wherein the image sensor is disposed at the imaging surface of the optical system. The camera module of claim 15, wherein, The camera module also includes a stabilization drive mechanism, which drives the image sensor to move on a plane parallel to the imaging surface to achieve optical image stabilization. A camera module includes an optical system and an image sensor. The optical system includes a lens assembly and a prism. The prism has a first surface, a second reflective surface, and a third reflective surface. The lens assembly and the image sensor are located on one side of the first surface and opposite to the first surface. The second reflective surface is inclined to the first surface and opposite to the lens assembly in the axial direction of the lens assembly. The third reflective surface is inclined to the first surface and opposite to the image sensor in the perpendicular direction of the imaging surface of the lens assembly. At least a portion of the light emitted from the lens assembly can enter the prism from the first surface and exit from the first surface onto the image sensor after being reflected by at least the second and third reflecting surfaces. The camera module of claim 17, wherein, The prism also has a fourth reflecting surface opposite to the first surface and located between the second reflecting surface and the third reflecting surface. Light rays incident on the prism from the first surface can be reflected sequentially by the second reflecting surface, the first surface, the fourth reflecting surface, the first surface, the fourth reflecting surface, the first surface, the first surface, and the third reflecting surface before exiting from the first surface. The camera module of claim 17, wherein, The lens assembly includes multiple lenses arranged coaxially, wherein the lens closest to the image side is the image-end lens. The lenses in the lens assembly other than the image-end lens are fixed relative to the image sensor, and the image-end lens is axially movable among the other lenses in the lens assembly and the prism. The camera module of claim 17, wherein, The optical system satisfies the following condition: 11≤L / IMGH≤15; TTL / IMGH≤17; Where L is the geometric path of light in the prism, IMGH is half the diagonal length of the effective pixel area on the imaging surface of the optical system, and TTL is the on-axis distance from the object side of the lens closest to the object end in the lens assembly to the imaging surface. An electronic device comprising a camera module as described in any one of claims 15-20.

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