Lens assembly, camera module, and electronic device

Abstract

The present application provides a lens assembly, a camera module, and an electronic device. The lens assembly includes a first lens group, a prism, and a second lens group arranged consecutively from an object side to an image side. The prism has a first surface, a second surface, and a third surface. The second and third surfaces are located on a first side of the first surface. The first lens group and the second lens group are located on a second side of the first surface. The first side faces the second side. The object side and the image side are located on the second side of the first surface. A first included angle between the first surface and the second surface is equal to a second included angle between the first surface and the third surface. The first included angle is greater than 0° and less than 45°. A first reflective film is located on the second surface, and a second reflective film is located on the third surface. With this arrangement, an upright camera module can be implemented, and as a result, the volume of the camera module can be reduced, assuming a long focal length is implemented.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202211661120.7, entitled "Lens Assembly, Camera Module, and Electronic Device," filed with the State Intellectual Property Administration of China on December 23, 2022, which application is incorporated herein by reference in its entirety.

[0002] TECHNICAL FIELD Embodiments of the present application relate to the field of optical imaging technology, and in particular to lens assemblies, camera modules, and electronic devices. [Background technology]

[0003] Camera modules have become an essential functional component in electronic products such as mobile phones, tablets, notebook computers, and wearable devices. The development of lighter, thinner, and more multi-functional electronic devices has led to the gradual development of smaller and thinner camera modules on electronic devices. However, the image capture efficiency and requirements are expected to be as high as those of single-lens reflex cameras, and the functional efficiency and volume of camera modules are gradually becoming one of the important features of electronic devices.

[0004] A camera module includes a lens assembly and an image sensor. The lens assembly typically includes multiple lenses arranged consecutively along an optical axis. After passing through the lens assembly, light is emitted to the image sensor, which performs photoelectric conversion for imaging. Therefore, the performance of the lens assembly directly determines the imaging performance of the camera module. As the demand for long-distance photography by cameras in electronic devices becomes increasingly apparent, camera modules in related art use a "periscope" design to achieve a long focal length to meet the long-distance photography demand. However, the "periscope" camera module has a problem of large volume. When the "periscope" camera module is placed in an electronic device, it is difficult to place other components in the electronic device.

[0005] Therefore, how to reduce the volume of a camera module assuming that a long focal length will be implemented is an urgent issue that needs to be resolved. Summary of the Invention

[0006] SUMMARY OF THE INVENTION Embodiments of the present application provide a lens assembly, a camera module, and an electronic device to reduce the volume of a camera module provided that the camera module implements a long focal length.

[0007] A first aspect of the present application provides a lens assembly including at least a first lens group, a prism, and a second lens group arranged consecutively from an object side to an image side. The prism has a first surface, a second surface, and a third surface. The second surface and the third surface are located on a first side of the first surface. The first lens group and the second lens group are located on a second side of the first surface. The first side faces the second side. The object side and the image side are located on the second side of the first surface. A first included angle between the first surface and the second surface is equal to a second included angle between the first surface and the third surface. The first included angle is greater than 0° and less than 45°. A first reflective film is located on the second surface, and a second reflective film is located on the third surface. The first surface is configured to: transmit light passing through the first lens group to the prism; reflect, to the third surface, at least a portion of the light reflected from the first reflecting film to the first surface; and transmit, to the outside of the prism, the light reflected from the second reflecting film to the first surface. The first reflecting film is configured to reflect, to the first surface, the light entering the prism via the first surface. The second reflecting film is configured to reflect, to the first surface, the light reflected from the first surface to the third surface.

[0008] This embodiment of the present application uses a prism to refract the optical path, so that the first lens group and the second lens group can be located on the same side of the prism, reducing the size of the lens assembly in the horizontal direction and implementing an upright design. In this way, the volume of the lens assembly can be reduced, reducing the volume of the camera module, thereby implementing a compact and low-cost camera module. Additionally, because the lens assembly adopts an upright design, the size of the image sensor cooperating with the second lens group is no longer limited by the thickness of the electronic device. The size of the image sensor depends on the height or width of the electronic device. Therefore, the image sensor can be enlarged, and the detection target surface of the image sensor can be enlarged, resulting in a large target surface design.

[0009] In a possible implementation, the prism satisfies the relation sin2θ1>>1 / n, where θ1 is the first included angle and n is the refractive index of the prism.

[0010] In this arrangement, it can be ensured that the total internal reflection phenomenon occurs for the light reflected by the first reflective film to the first surface, and a part of the light can be prevented from being transmitted from the first surface to the outside of the prism, thereby avoiding the waste of signal energy and the risk of stray light.

[0011] In a possible implementation, at least one of the first lens group, the second lens group, and the prism may move along a preset direction, the preset direction being parallel to an optical axis direction of the first lens group and an optical axis direction of the second lens group.

[0012] In this arrangement, focusing can be implemented at a short object distance, thereby implementing a long focus minute distance effect and capturing detailed scenarios by using a long focus camera module.

[0013] In a possible implementation, the prism is an isosceles triangle prism or an isosceles trapezoid prism, and can refract the optical path to implement an upright camera module.

[0014] In a possible implementation, the first reflective film is a metal reflective film or an insulating reflective film. The second reflective film is a metal reflective film or an insulating reflective film.

[0015] In a possible implementation, the first lens group has a positive focal refractive power.

[0016] In this arrangement, light is converged and incident on the prism through the first lens group. As a result, the size of the prism can be effectively reduced, and a miniaturized design of the camera module can be implemented.

[0017] In a possible implementation, the lens closest to the subject side within the first lens group has a positive focal refractive power, and the subject side surface of the lens is a convex surface.

[0018] In this arrangement, light can be converged, which helps to increase the amount of light entering the lens assembly.

[0019] In a possible implementation, the first lens group satisfies the relational expression 0.05 < <TTL1 / f < <0.3, where TTL1 is the total optical length of the first lens group and f is the focal length of the lens assembly. <00000 June 3>

[0020] In this arrangement, the total system length of the lens assembly can be reduced. A smaller value indicates a smaller total system length.

[0021] In a possible implementation, the first lens group satisfies the relational expression 0.5 < <L / TTL1 < <3, where L is the relative maximum movement amount of the first lens group and the second lens group at different subject distances.

[0022] In this arrangement method, the occupied space required by the lens assembly can be reduced. A smaller value indicates a smaller minute distance movement stroke and a smaller occupied space.

[0023] In a possible implementation, the second lens group satisfies the relational expression 0.05 < <TTL2 / f < <0.3, where TTL2 is the total optical length of the second lens group.

[0024] In this arrangement method, the total system length of the lens assembly can be reduced. A smaller value indicates a smaller total system length.

[0025] In a possible implementation, the first lens group includes at least two lenses having a focusing power. The second lens group includes at least one lens having a focusing power.

[0026] The second aspect of the present application provides a camera module. The camera module includes at least an image sensor and a lens assembly according to any one of the first aspects. The image sensor is of the second lens group of the lens assembly and is located on the side facing the image side. An upright lens assembly is included. Therefore, miniaturized design, a large target surface, and low cost can be implemented for the camera module.

[0027] The third aspect of the present application provides an electronic device. The electronic device includes at least a housing and a camera module according to the second aspect. The camera module is disposed on the housing. The camera module is included, and the camera module is characterized by low cost, better imaging quality, and ultra-thin performance. This helps to reduce the cost of the electronic device, improve the shooting performance of the electronic device, and facilitate the thin-type design of the electronic device.

Brief Description of the Drawings

[0028] [Figure 1] It is a diagram of the structure of an electronic device according to an embodiment of the present application. [Figure 2] FIG. 1 is a cross-sectional view of a camera module according to a related art. [Figure 3] 1 is a diagram of a structure of a camera module according to an embodiment of the present application; [Figure 4] 3A and 3B are diagrams illustrating the structure of a first prism according to an embodiment of the present application. [Figure 5] 4A and 4B are diagrams illustrating the structure of a second prism according to an embodiment of the present application. [Figure 6] FIG. 2 is a top view of a third prism according to an embodiment of the present application. [Figure 7] FIG. 10 is a top view of a fourth prism according to an embodiment of the present application. [Figure 8] FIG. 10 is a diagram of a simulated configuration of another camera module in a short object distance state according to an embodiment of the present application. [Figure 9] FIG. 10 is a diagram of a simulated configuration of another camera module in a long object distance state according to an embodiment of the present application. [Figure 10] FIG. 9 is a diagram of a spherical aberration curve for the lens assembly according to the embodiment shown in FIG. 8.

[0029] Reference Number: 100: Electronic devices; 10: Camera module; 11: Lens assembly; 111: first lens group; 1111: first lens; 1112: second lens; 1113: third lens; 112: Prism; 113: second lens group; 1131: fourth lens; 1132: fifth lens; 114: 1st reflective film; 115:Second reflective film; 12: Image sensor; 13: Optical filter; 20: Housing; X: Width direction; Y: thickness direction; Z: Height direction. DETAILED DESCRIPTION OF THE INVENTION

[0030] The terms used in the implementation of this application are only used to describe specific embodiments of this application, but are not intended to limit the application.

[0031] For ease of understanding, relevant technical terms in the embodiments of the present application will first be explained and described.

[0032] Focal length, also called focal length, is a measurement method for measuring the convergence or divergence of light in an optical system, and refers to the vertical distance from the optical center of a lens or lens group to the focal plane when a sharp image of an infinite scene is formed on the focal plane through the lens or lens group. From a practical point of view, focal power can be understood as the distance from the center of the lens assembly to the image plane.

[0033] The total track length (TTL) is the total length from the vertex of the first lens located adjacent to the subject side of the lens assembly to the image plane of the lens assembly, and is also called the total optical length.

[0034] The subject-side space partitioned by the lens is the space in which the photographed subject is located.

[0035] The subject side bounded by the lens assembly is the side on which the subject being photographed is located. The surface of the lens facing the subject side is the subject-side surface of the lens.

[0036] The image side is the side on which the image of the photographed subject is located. The surface of a lens that faces the image side is the image-side surface.

[0037] The focal power represents the ability of a lens to refract incident parallel rays of light.

[0038] Positive focal power indicates that the lens has a positive focal length and has the effect of converging light.

[0039] Negative focal power indicates that the lens has a negative focal length and has the effect of diverging light.

[0040] Target surface refers to the light-sensitive surface of the image sensor. A larger target surface indicates a larger amount of light sensed by the image sensor and a larger image height for imaging.

[0041] The electronic devices provided in the embodiments of the present application may include, but are not limited to, electronic devices having a camera module, such as a mobile phone, a tablet computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, an intercom, a netbook, a point-of-sale machine, a personal digital assistant (PDA), a wearable device, a virtual reality device, or an in-vehicle device.

[0042] In this embodiment of the present application, an example in which the electronic device is a mobile phone is used. The mobile phone may be a bar-shaped mobile phone, or the mobile phone may be a foldable mobile phone. Specifically, the following uses an example in which the electronic device is a bar-shaped mobile phone for description.

[0043] FIG. 1 is a diagram of the structure of an electronic device according to an embodiment of the present application.

[0044] See Fig. 1. The electronic device 100 may include a housing 20 and a camera module 10. The camera module 10 may be disposed on the housing 20, and the camera module 10 is configured to implement a photographing function.

[0045] Camera module 10 may be located on the front side (the side having the display screen) of electronic device 100 and configured to take a selfie or photograph another subject. Alternatively, referring to FIG. 1 , camera module 10 may be located on the rear side (the side having the display screen) of electronic device 100 and configured to photograph another subject, or of course, configured to take a selfie.

[0046] The number of camera modules 10 included in the electronic device 100 may be one, or the number of camera modules 10 may be multiple to meet different photographing requirements.

[0047] The electronic device 100 may further include other structural members. For example, still referring to FIG. 1 , a speaker 30 may further be disposed on the housing 20 of the electronic device 100. The speaker 30 may be configured to reproduce audio, etc., of the electronic device 100. The housing 20 of the electronic device 100 may further be provided with a data interface 40. The data interface 40 may be configured to provide power to the electronic device 100. Alternatively, the data interface 40 may be configured to connect the electronic device 100 to a headset, an external multimedia device (e.g., an external camera or an external projection device), or the like.

[0048] Of course, in some other examples, the electronic device 100 may further include other structural members, such as sensors, processors, circuit boards, and driving structures, to complete the functionality of the electronic device 100. The structural members are not limited in this embodiment of the present application.

[0049] Typically, camera module 10 may include a lens assembly 11 and an image sensor 12. Light may enter camera module 10 from lens assembly 11. Specifically, light reflected from a photographed object may enter lens assembly 11. After the light enters lens assembly 11 and lens assembly 11 adjusts and controls the light path, an optical image is generated, and the light is irradiated onto a photosensitive surface of image sensor 12. Image sensor 12 may implement a photoelectric conversion function, and image sensor 12 receives the optical image and converts the optical image into an electrical signal for imaging display.

[0050] The camera module 10 may further include an image processor, a memory, etc. The image sensor 12 may send electrical signals to the image processor and memory for processing, and then display the captured image of the subject via a display screen of the electronic device 100.

[0051] The optical performance of lens assembly 11 significantly affects the imaging quality and effectiveness of camera module 10. For example, the number of apertures in lens assembly 11 affects functions such as night photography, video shooting, background blur, and image capture. In other words, a camera module 10 using a wider aperture has better imaging quality and effectiveness in scenarios such as night photography, video shooting, background blur, and image capture.

[0052] The size of the target surface of the lens assembly 11 is also one of the important factors affecting the imaging quality. A camera module 10 with a larger target surface helps to improve the brightness and resolution of the imaging of the camera module 10, and obtains better imaging quality.

[0053] The volume of the camera module 10 affects the thin design of the electronic device 100. A camera module 10 with a smaller volume requires less space. On the one hand, it may be less difficult to install the camera module 10. On the other hand, it may be easier to arrange other components in the electronic device 100.

[0054] FIG. 2 is a cross-sectional view of a camera module in the related art. As the demand for long-distance photography by cameras in electronic devices becomes increasingly apparent, camera modules in the related art use a "periscope" design. As shown in FIG. 2, an image sensor 33 is located at the rear end of an optical system 32. A reflecting prism 31 is introduced at the front end of the optical system 32 to fold the optical axis (e.g., the dashed line with an arrow in the figure). The lenses of the optical system 32 are arranged in parallel to implement a long focal length design, so that the demand for long-distance photography can be met. However, the volume of a "periscope" camera module is large. When a "periscope" camera module is placed in an electronic device, it occupies a lot of space in the electronic device, making it difficult to place other components in the electronic device. In addition, when a "periscope" camera module is placed in an electronic device, the horizontal size A of the "periscope" camera module is the size in the height direction of the electronic device, and the vertical size B of the "periscope" camera module is the size in the thickness direction of the electronic device. Because the thickness of the electronic device is small, the vertical dimension B of the "periscope" camera module cannot be excessively large. As a result, the size of the image sensor is limited by the vertical dimension B, and the target surface of the image sensor cannot be large, so a large target surface design cannot be implemented. Therefore, how to reduce the volume of the camera module on the premise that a long focal length is implemented becomes an urgent problem to be solved.

[0055] In consideration of this, the embodiment of the present application provides a lens assembly 11 with an upright design to implement a camera module 10 with a long focal length. In addition, provided that a long focal length is implemented, the volume of the camera module 10 can be reduced, the design requirements for large target surfaces can be met, and the cost of the camera module 10 can be further reduced.

[0056] Hereinafter, the lens assembly 11 provided in the embodiment of the present application and the camera module 10 including the lens assembly 11 will be described in detail with reference to the accompanying drawings.

[0057] FIG. 3 is a diagram of the structure of a camera module according to an embodiment of the present application. Please refer to FIG. 3. The camera module 10 provided in the embodiment of the present application includes a lens assembly 11 and an image sensor 12. The image sensor 12 is located at an end of the lens assembly 11 closer to the image side. A photosensitive surface (which may also be referred to as an image surface) of the image sensor 12 faces the second lens group 113 of the lens assembly 11. Light entering the camera module 10 from the lens assembly 11 may be irradiated onto the photosensitive surface of the image sensor 12 after passing through the lens assembly 11 to implement light imaging.

[0058] Image sensor 12 may be a charge-coupled device (CCD), a complementary metal oxide semiconductor (CMOS), or another device capable of implementing a photoelectric conversion function.

[0059] Still referring to Figure 3, camera module 10 may further include an optical filter 13. Optical filter 13 may be located between lens assembly 11 and image sensor 12. Light passing through lens assembly 11 passes through optical filter 13 and is then irradiated onto the photosensitive surface of image sensor 12. Optical filter 13 has an optical filtering function and allows light within a specific wavelength range to pass, which may help to filter out stray light that does not contribute to imaging and improve imaging quality.

[0060] The camera module 10 may further include a lens cone (not shown), in which the lens assembly 11, the optical filter 13, the image sensor 12, etc. may be disposed.

[0061] 3, the lens assembly 11 may include a first lens group 111, a prism 112, and a second lens group 113 arranged consecutively from the object side to the image side. The first lens group 111 and the second lens group 113 are located on the same side of the prism 112. The first lens group 111 is configured to connect the object-side space and the prism 112. The second lens group 113 is configured to connect the image sensor 12 and the prism 112. Light entering the camera module 10 enters the prism 112 via the first lens group 111 and then enters the second lens group 113 via the prism 112. Light passing through the second lens group 113 may be irradiated onto the photosensitive surface of the image sensor 12.

[0062] 3 that because the prism 112 can refract the light path, the first lens group 111 and the second lens group 113 can be located on the same side of the prism 112, thereby reducing the size of the lens assembly 11 in the horizontal direction, which helps to reduce the volume of the camera module 10 and implements miniaturization and low cost. When the camera module 10 is disposed in the electronic device 100, the space occupied by the camera module 10 is reduced, making it easier to arrange other components in the electronic device 100.

[0063] It can be seen from FIG. 3 that because the second lens group 113 and the first lens group 111 are located on the same side of the prism 112, this is equivalent to placing the first lens group 111 and the second lens group 113 in parallel. Therefore, the image sensor 12 cooperating with the second lens group 113 can be arranged parallel to the first lens group 111. When the camera module 10 is placed in the electronic device 100, the first lens group 111 faces the light entrance. Therefore, the horizontal size of the camera module 10 is the size of the camera module 10 in the height or width direction of the electronic device 100. The vertical size of the camera module 10 is the size of the camera module 10 in the thickness direction of the electronic device 100. Therefore, the thickness of the image sensor 12 may be limited by the thickness of the electronic device 100. However, the length and width of the image sensor 12 may not be limited by the thickness of the electronic device 100. Therefore, to implement large target surface designs, the size of image sensor 12 may be increased and the photosensitive surface of image sensor 12 may be enlarged.

[0064] As shown in FIG. 3, the prism 112 has a first surface, a second surface, and a third surface. The second surface and the third surface are located on a first side of the first surface. The first lens group 111 and the second lens group 113 are located on a second side of the first surface. The first side faces the second side. The object side and the image side are located on the second side of the first surface. A first included angle (θ1 shown in FIG. 3) between the first surface and the second surface is equal to a second included angle (θ2 shown in FIG. 3) between the first surface and the third surface. The first included angle is greater than 0° and less than 45°. A first reflective film 114 is disposed on the second surface, and a second reflective film 115 is disposed on the third surface. In this arrangement, it can be ensured that the light passing through the first lens group 111 and entering the prism 112 enters the second lens group 113 after being refracted by the prism 112, thereby achieving the purpose of refracting the optical path.

[0065] The first included angle is equal to the second narrow angle, so that the optical axis of the incident light beam of the prism 112 can be ensured to be parallel to the optical axis of the emerging light beam of the prism 112, thereby avoiding chromatic aberration caused by the dispersion effect of the prism 112 and affecting imaging. In addition, this further helps ensure that the photosensitive surface of the image sensor 12 is parallel to the light entrance. The optical axis of the incident light beam of the prism 112 is equal to the optical axis of the first lens group 111 (e.g., dashed line L1 in FIG. 3). The optical axis of the emerging light beam of the prism 112 is equal to the optical axis of the second lens group 113 (e.g., dashed line L2 in FIG. 3).

[0066] The first included angle is set between 0° and 45° to ensure that the light ray reflected by the first reflective film 114 can reach the first surface. In addition, since the first included angle is equal to the second narrow angle, the second narrow angle is also between 0° and 45°, which can also ensure that the light ray reflected by the second reflective film 115 can reach the first surface.

[0067] As shown in FIG. 3 , when light from the subject side enters the lens assembly 11, the light first enters the first lens group 111. The light passing through the first lens group 111 then passes through the prism 112 via the first surface. The light passing through the first surface is then reflected back to the first surface by the first reflective film 114 on the second surface. The first surface then reflects the light reflected from the first reflective film 114 back to the first surface to the third surface. The light reflected from the first surface to the third surface is immediately reflected back to the first surface by the second reflective film 115. Finally, the light reflected from the first surface by the second reflective film 115 is transmitted out of the prism 112 via the first surface and enters the second lens group 113. The light transmitted out of the prism 112 via the first surface passes successively through the second lens group 113 and the optical filter 13 and is then irradiated onto the image sensor 12.

[0068] It should be noted that when the incident angle of the light reflected by the first reflective film 114 to the first surface on the first surface is small, part of the light reflected by the first reflective film 114 to the first surface is transmitted to the outside of the first surface via the first surface. Therefore, to ensure that the light passing through the first lens group 111 can enter the second lens group 113 via the prism 112, the first surface can reflect at least part of the light reflected from the first reflective film 114 to the first surface to the third surface.

[0069] It should be noted that the first surface can be a flat or curved surface. When the first surface is flat, the optical axis direction of the first lens group 111 and the optical axis direction of the second lens group 113 are perpendicular to the first surface.

[0070] In a possible implementation, the prism 112 satisfies the relationship sin 2 θ 1 >> 1 / n, where θ 1 is the first included angle and n is the refractive index of the prism 112 .

[0071] If the incident angle on the first surface of the light reflected by the first reflective film 114 to the first surface is small, part of the light reflected by the first reflective film 114 to the first surface will be transmitted to the outside of the first surface through the first surface, which may result in wasted signal energy and the risk of stray light. Therefore, the relationship sin2θ1>>1 / n is used, so that the incident angle on the first surface of the light reflected by the first reflective film 114 to the first surface is greater than or equal to the critical angle. In this way, the total internal reflection phenomenon can be guaranteed to occur for the light reflected by the first reflective film 114 to the first surface, and part of the light can be prevented from being transmitted to the outside of the prism 112 from the first surface, thereby avoiding the wasted signal energy and the risk of stray light.

[0072] In a possible implementation, the first reflective film 114 is a metallic reflective film or an insulating reflective film, and the second reflective film 115 is a metallic reflective film or an insulating reflective film.

[0073] The material of the metallic reflective film may include, but is not limited to, at least one of the following materials: silver, aluminum, copper, and gold. The insulating reflective film may be a non-metallic composite film. In addition, the material of the first reflective film 114 may be the same as or different from that of the second reflective film 115.

[0074] In a possible implementation, the prism 112 may be an isosceles triangular prism (e.g., as shown in FIG. 4) or an isosceles trapezoidal prism (e.g., as shown in FIG. 5), which may refract the optical path to implement an upright camera module 10. FIG. 4 is a diagram of the structure of a first prism according to an embodiment of the present application. FIG. 5 is a diagram of the structure of a second prism according to an embodiment of the present application.

[0075] It should be noted that in addition to being an isosceles triangular prism or an isosceles trapezoidal prism, prism 112 may alternatively be a polygonal prism, such as a pentagonal prism or a hexagonal prism, provided that prism 112 has a first surface, a second surface, and a third surface, and the first surface, the second surface, and the third surface form an isosceles triangle relationship, satisfying θ1=θ2 and 0°<θ1°.

[0076] Assuming that an isosceles triangle relationship is formed, at least two of the first, second, and third surfaces may intersect, or the first, second, and third surfaces may not intersect with each other. For example, as shown in FIG. 6, the second surface intersects with the third surface, and the first surface does not intersect with the second and third surfaces. FIG. 6 is a top view of a third prism according to an embodiment of the present application. Alternatively, any two of the first, second, and third surfaces may not intersect, as shown in FIG. 7. FIG. 7 is a top view of a fourth prism according to an embodiment of the present application.

[0077] In a possible implementation, at least one of the first lens group 111, the second lens group 113, and the prism 112 may move along a preset direction that is parallel to the optical axis direction of the first lens group 111 (e.g., L1 in FIG. 3) and the optical axis direction of the second lens group 113 (e.g., L2 in FIG. 3). In this arrangement, focusing can be implemented at a short object distance, thereby implementing a long focus minute distance effect and capturing detailed scenarios by using the long focus camera module 10.

[0078] It may be understood that at least one of the first lens group 111, the second lens group 113, and the prism 112 may be moved at a close object distance. For example, the first lens group 111 and the second lens group 113 may be moved along a preset direction relative to the prism 112, and both the first lens group 111 and the second lens group 113 may be moved to implement a long focal length effect.

[0079] In a possible implementation, the first lens group 111 has a positive focal power. In this arrangement, light is converged and incident on the prism 112 through the first lens group 111, so that the size of the prism 112 can be effectively reduced and a compact design of the camera module 10 can be implemented.

[0080] In a possible implementation, the lens in the first lens group 111 closest to the subject side has a positive focal power and the subject-facing side of the lens is convex. In this arrangement, light can be focused, which helps to increase the amount of light entering the lens assembly 11.

[0081] It can be understood that the lenses in the first lens group 111 other than the lens closest to the subject side can have positive or negative focal power, but this is not limited here.

[0082] In a possible implementation, the first lens group 111 satisfies the relational expression 0.05 << TTL1 / f << 0.3, where TTL1 is the total optical length of the first lens group 111 and f is the focal length of the lens assembly 11. In this arrangement method, the total system length of the lens assembly 11 can be reduced.

[0083] The specific ratio of TTL1 / f is not limited in this specification. For example, the ratio of TTL1 / f, although not limited, may include 0.055, 0.06, 0.065, 0.067, 0.07, 0.08, 0.09, 0.1, 0.15, 0.18, 0.19, 0.2, 0.21, 0.22, 0.25, 0.256, 0.287, 0.289, 0.297, etc.

[0084] In a possible implementation, the first lens group 111 satisfies the relational expression 0.5 << L / TTL1 << 3, where L is the relative maximum movement amount of the first lens group 111 and the second lens group 113 at different object distances. In this arrangement method, the occupied space required by the lens assembly 11 can be reduced.

[0085] The specific ratio of L / TTL1 is not limited in this specification. For example, the ratio of L / TTL1, although not limited, may include 0.6, 0.65, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.25, 1.3, 1.39, 1.5, 1.9, 2.0, 2.5, 2.6, 2.7, 2.9, 2.95, 2.987, etc.

[0086] It should be noted that the relative maximum movement amount is the maximum movement amount of the relative movement of the first lens group 111 and the second lens group 113 in the optical axis direction. When the first lens group 111 and the second lens group 113 move relative to each other in the optical axis direction, at least one of the first lens group 111 and the second lens group 113 moves along the optical axis direction.

[0087] In a possible implementation, the second lens group 113 satisfies the relational expression 0.05 < <TTL2 / f < <0.3, where TTL2 is the total optical length of the second lens group 113. In this arrangement method, the total system length of the lens assembly 11 can be reduced.

[0088] The specific ratio of TTL2 / f is not limited in this specification. For example, the ratio of TTL2 / f, although not limited, may include 0.055, 0.06, 0.065, 0.067, 0.07, 0.08, 0.09, 0.1, 0.15, 0.18, 0.19, 0.2, 0.21, 0.22, 0.25, 0.256, 0.287, 0.289, 0.297, etc.

[0089] In a possible implementation, the first lens group 111 includes at least two lenses having focal refractive power. The second lens group 113 includes at least one lens having focal refractive power. In this arrangement method, it can be guaranteed that light enters the prism 112 through the first lens group 111, and the light passing through the prism 112 can be irradiated onto the image sensor 12 through the second lens group 113.

[0090] Hereinafter, with reference to specific embodiments, the structure and performance of the lens assembly 11 provided in the present application will be described.

[0091] FIG. 8 is a diagram of a simulation structure of another camera module in a short subject distance state according to an embodiment of the present application. FIG. 9 is a diagram of a simulation structure of another camera module in a long subject distance state according to an embodiment of the present application.

[0092] In the present embodiment of the present application, as shown in FIGS. 8 and 9, the camera module 10 includes a lens assembly 11, an image sensor 12, and an optical filter 13. The optical filter 13 is located between the second lens group 113 and the image sensor 12. During use, light is incident from the first lens group 111 onto the prism 112. The light emerging from the prism 112 continuously passes through the second lens group 113 and the optical filter 13, and finally converges onto the image sensor 12.

[0093] The prism 112 is an isosceles prism 112. A first reflective film 114 is disposed on the second surface of the prism 112, and a second reflective film 115 is disposed on the third surface of the prism 112. In addition, the first included angle is 30°, so that the light reflected by the first reflective film 114 and the second reflective film 115 can reach the first surface. In addition, the refractive index n of the prism 112 is equal to 1.7, sin 2θ1 is approximately equal to 0.866, and 1 / n is approximately equal to 0.588, which can ensure that the total internal reflection phenomenon occurs for the light reflected by the first reflective film 114 to the first surface.

[0094] The first lens group 111 includes three lenses with focal power, and the second lens group 113 includes two lenses with focal power.

[0095] When the camera module 10 photographs objects at different subject distances, the first lens group 111 moves along the optical axis direction of the first lens group 111 to implement focusing and ensure clarity.

[0096] The first lens group 111 is a lens group with positive focal power, which can compress and converge the light rays into the prism 112, so that the size of the prism 112 can be effectively reduced.

[0097] The lens in the first lens group 111 closest to the object side has positive focal power, and the object side surface of the lens is convex.

[0098] The total optical length of the first lens group 111 and the focal length of the lens assembly 11 are:

number

[0099] The total optical length of the second lens group 113 and the focal length of the lens assembly 11 are:

number

[0100] At different object distances, the maximum relative movement L of the first lens group 111 and the second lens group 113 and the total optical length of the first lens group 111 are:

number

[0101] Table 1 shows the optical parameters of each optical element in the camera module 10 provided in this embodiment. [Table 1] L1 is the first lens 1111, L2 is the second lens 1112, L3 is the third lens 1113, L4 is the fourth lens 1131, L5 is the fifth lens 1132, and IR is the optical filter 13.

[0102] R is the radius of curvature of the optical element (such as the lens or optical filter 13) at the position corresponding to the optical axis.

[0103] D1 is the thickness of the optical element or the thickness of the gap between the optical elements in the optical axis direction.

[0104] Nd is the refractive index of each optical element irradiated by the d-line, and VD is the Abbe number of the optical element.

[0105] Table 2 shows the conic coefficients and aspherical coefficients of each lens in the camera module 10 according to this embodiment. [Table 2] It can be seen from Table 2 that the first through fifth lenses include a total of eight aspheric surfaces. That is, lens assembly 11 includes four aspheric lenses. All even aspheric types z of lenses in lens assembly 11 have, but are not limited to, the following aspheric formulas:

number

[0106] See Table 3 for the optical parameters of the camera module 10 including the above mentioned lenses.

[0107] Table 3 shows the optical parameters of the camera module 10 provided in this embodiment. [Table 3] It can be seen from Table 3 that the camera module 10 provided in this embodiment of the present application features a large target surface and can implement a long focal length effect.

[0108] FIG. 10 is a diagram of spherical aberration curves for the lens assembly 11 according to the embodiment shown in FIG. 8. The horizontal coordinate represents the defocus amount (unit: mm). The vertical coordinate represents the normalized aperture. The different curves from left to right represent different wavelengths: 470 nm, 510 nm, 555 nm, 610 nm, and 650 nm. The curves represent the deviation (defocus amount) between the optimal image plane and the actual image plane of the system with different aperture bands. A smaller absolute value represents a better aberration correction effect and higher imaging quality of the system. According to the results in FIG. 10, within the current full wavelength and full aperture band range, all spherical aberrations are less than or equal to 0.04 mm, and the system aberrations are well corrected.

[0109] It should be noted that in the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installation," "connected to," and "connection" should be understood in a broad sense. For example, the connection may be a fixed connection, an indirect connection using an intermediate medium, or an indirect connection between two elements or an interaction relationship between two elements. Those skilled in the art may understand the specific meanings of the above terms in the embodiments of the present application based on specific situations.

[0110] In this specification, claims, and accompanying drawings of embodiments of this application, the terms "first," "second," "third," "fourth," etc. (when present) are intended to distinguish between similar objects, but do not necessarily indicate a particular order or sequence.

Claims

1. A lens assembly comprising a first lens group, a prism, and a second lens group arranged successively from a subject side to an image side, the prism has a first surface, a second surface, and a third surface, the second surface and the third surface being located on a first side of the first surface, the first lens group and the second lens group being located on a second side of the first surface, the first side facing the second side, and the subject side and the image side being located on the second side of the first surface; a first included angle between the first surface and the second surface equal to a second included angle between the first surface and the third surface, the first included angle being greater than 0° and less than 45°, a first reflective film being disposed on the second surface, and a second reflective film being disposed on the third surface; The first surface is configured to: transmit light passing through the first lens group to the prism; reflect, to the third surface, at least a portion of the light reflected from the first reflecting film to the first surface; and transmit, to the outside of the prism, the light reflected from the second reflecting film to the first surface; the first reflective film is configured to reflect, to the first surface, light that enters the prism through the first surface; The second reflective film is configured to reflect, to the first surface, light reflected from the first surface to the third surface. Lens assembly.

2. The prism has a relational expression sin2θ １ >>1 / n, where θ １ 2. The lens assembly of claim 1, wherein: is the first included angle; and n is the refractive index of the prism.

3. 3. The lens assembly of claim 1, wherein at least one of the first lens group, the second lens group, and the prism is movable along a predetermined direction, the predetermined direction being parallel to an optical axis direction of the first lens group and an optical axis direction of the second lens group.

4. 4. The lens assembly according to claim 1, wherein the prism is an isosceles triangular prism or an isosceles trapezoidal prism.

5. The lens assembly according to claim 1 , wherein the first reflective film is a metallic reflective film or an insulating reflective film, and the second reflective film is a metallic reflective film or an insulating reflective film.

6. 6. A lens assembly according to claim 1, wherein the first lens group has a positive focal power.

7. 7. The lens assembly of claim 1, wherein the lens in the first lens group closest to the subject side has a positive focal power and the subject-side surface of the lens is convex.

8. 8. The lens assembly of claim 1, wherein the first lens group satisfies the relationship 0.05<<TTL1 / f<<0.3, where TTL1 is the total optical length of the first lens group and f is the focal length of the lens assembly.

9. 9. The lens assembly of claim 1, wherein the first lens group satisfies a relationship 0.5<<L / TTL1<<3, where L is a maximum relative movement amount of the first lens group and the second lens group at different object distances.

10. 10. The lens assembly of claim 1, wherein the second lens group satisfies the relationship 0.05<<TTL2 / f<<0.3, where TTL2 is the total optical length of the second lens group.

11. 11. A lens assembly according to any one of claims 1 to 10, wherein the first lens group comprises at least two lenses with focal power and the second lens group comprises at least one lens with focal power.

12. 12. A camera module comprising at least an image sensor and a lens assembly according to claim 1, wherein the image sensor is in the second lens group of the lens assembly and is located on a side facing the image side.

13. An electronic device comprising at least a housing and a camera module according to claim 12, wherein the camera module is disposed on the housing.

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