Periscopic optical system and anti-shake mechanism driving method

Abstract

The invention discloses a periscopic optical system and an anti-shake mechanism driving method.The periscopic optical system comprises a lens group and a light turning element located on the object side of the lens group, the light turning element is used for turning light from a first optical axis AX1 to a second optical axis AX2 so that the light can penetrate through the lens group, and the periscopic optical system further comprises an anti-shake lens with positive focal power, the anti-shake lens is located between the light steering element and the lens group, and the anti-shake lens is suitable for translating in a plane perpendicular to the second optical axis AX2; and the anti-shake mechanism is used for driving the anti-shake lens to translate, so that the overall size of the periscopic optical system is reduced and the reliability of the driving motor is improved on the basis of correcting the shake of the periscopic optical system.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging, and in particular to a periscope optical system and an anti-shake mechanism driving method. Background Art

[0002] In recent years, with the widespread adoption of portable electronic devices like smartphones and smartwatches, the market has focused on their camera performance. To meet the market's demand for telephoto and super-telephoto imaging, telephoto lenses have become increasingly popular. Periscope optical systems, which fold the optical path, facilitate the miniaturization of telephoto lenses, allowing them to be integrated into compact pan-tilt devices.

[0003] In addition, portable electronic devices are prone to shaking during shooting due to various reasons. For example, when holding a smartphone for shooting, it is often difficult for users to hold the phone steady for a long time, and the key presses during shooting can easily cause the phone to become unstable. These situations will cause the image in the viewfinder to shake, affecting the image quality.

[0004] Currently, the main methods for achieving anti-shake functions in periscope optical systems are lens group translation and prism rotation. Compensating for the jitter of the periscope optical system by translating the lens group results in a relatively large overall weight of the lens group, and the required displacement distance for achieving the anti-shake function is also relatively large, which results in excessive power consumption and slow response speed for the motor used to drive the lens group translation. Furthermore, it is not conducive to reducing the shoulder height of the camera module. Compensating for the jitter of the periscope optical system by prism rotation, due to technological development and increased requirements for image quality, the size of the photosensitive chip and aperture of the camera module in small devices have increased accordingly. The size and weight of the prism in the periscope optical system have also increased, resulting in excessive power consumption and slow response of the motor used to drive the prism rotation. Furthermore, it is not conducive to reducing the overall size of the camera module.

[0005] In summary, how to achieve optical image stabilization in a periscope optical system at a smaller space cost is a major problem that needs to be solved urgently. Summary of the Invention

[0006] One object of the present invention is to provide a periscope optical system that overcomes the shortcomings of the prior art and is able to reduce the overall size of the periscope optical system and improve the reliability of the drive motor on the basis of correcting the jitter of the periscope optical system.

[0007] Another object of the present invention is to provide a method for driving an anti-shake mechanism of a periscope optical system, so as to correct the shake of the periscope optical system.

[0008] In order to achieve at least one of the above purposes, the technical solution adopted by the present invention is: a periscope optical system, including a lens group and a light deflection element located on the object side of the lens group, the light deflection element is used to deflect light from the first optical axis AX1 to the second optical axis AX2 to pass through the lens group, and also includes: an anti-shake lens with positive optical power, the anti-shake lens is located between the light deflection element and the lens group, the anti-shake lens is suitable for translation in a plane perpendicular to the second optical axis AX2; an anti-shake mechanism, the anti-shake mechanism is used to drive the anti-shake lens to translate to correct the jitter of the periscope optical system.

[0009] Preferably, the first optical axis AX1 and the second optical axis AX2 are perpendicular to each other, the anti-shake lens is suitable for translating in a plane perpendicular to the optical axis AX2 and in a direction parallel to the first optical axis AX1, and / or the anti-shake lens is suitable for translating in a plane perpendicular to the optical axis AX2 and in a direction perpendicular to the first optical axis AX1.

[0010] As a preferred embodiment, the center thickness of the anti-shake lens is TC F , satisfying the following relationship: 0.96mm <TC F <2.4mm.

[0011] As a preferred embodiment, the center thickness of the anti-shake lens is TC F , the effective focal length of the periscope optical system is EFL X , satisfying the following relationship: 0.043<(TC F / EFL X )<0.107.

[0012] As a preferred embodiment, the effective aperture of the anti-shake lens is D F , the effective focal length of the periscope optical system is EFL X , the entrance pupil diameter of the periscope optical system is EPD X , satisfying the following relationship: (D F / EFL X )>0.17, (D F / EPD X )>0.418.

[0013] As a preferred embodiment, the effective focal length of the periscope optical system is EFL X The effective focal length of the anti-shake lens is EFL F , satisfying the following relationship: 1<(EFL X / EFL F )<1.55.

[0014] As a preference, the minimum gap between the anti-shake lens and the light deflection element is H1, and the minimum gap between the anti-shake lens and the lens group is H2, satisfying the following relationship: (H1 / H2)≥2.

[0015] As a preferred embodiment, the minimum gap between the anti-shake lens and the light deflection element is greater than the center thickness TC of the anti-shake lens. F .

[0016] As a preference, the periscope optical system also includes a front lens with positive optical power, the object side of the front lens is convex, the image side is concave, and the object side curvature radius of the front lens is smaller than the image side curvature radius of the front lens, and the front lens is located on the object side of the light deflecting element to converge the light.

[0017] As a preferred embodiment, the effective focal length of the periscope optical system is EFL X , the effective focal length of the front lens is EFL Q , satisfying the following relationship: 2.71<(EFL X / EFL Q )<4.45.

[0018] As a preference, the lens group includes at least five lenses, and the at least five lenses include: the first lens has a positive focal length, its object side is convex, and the image side is concave; the second lens has a negative focal length, its object side is convex, and the image side is concave; the third lens has a positive focal length, its object side is convex, and the image side is convex; the fourth lens has a positive focal length, its object side is concave, and the image side is convex; the fifth lens has a negative focal length, its object side is convex, and the image side is concave; wherein the anti-shake lens and the lenses in the lens group are all made of plastic.

[0019] As a preferred embodiment, the center thickness of the anti-shake lens is TC F The effective aperture of the anti-shake lens is D F , satisfying the following relationship: 5<((D F +0.05)×2 / TC F )<11.

[0020] To achieve at least one of the above objectives, the technical solution adopted by the present invention is: a method for driving an anti-shake mechanism, applied to the above-mentioned periscope optical system, comprising the steps of: a. setting a displacement plane, wherein the displacement plane is perpendicular to the second optical axis AX2 and has an X-axis and a Y-axis that are orthogonal to each other; b. obtaining an anti-shake signal from the periscope optical system and converting it into a correction amount along the X-axis and a correction amount along the Y-axis; c. the anti-shake mechanism drives the anti-shake lens to translate along the X-axis and / or the Y-axis within the displacement plane according to the correction amount to correct the shake of the periscope optical system.

[0021] As a preferred embodiment, the step b specifically includes detecting the jitter of the periscope optical system through a gyroscope, and converting the jitter into the anti-shake signal and feeding it back to the micro-control unit. The micro-control unit calculates the tilt angle caused by the jitter based on the anti-shake signal, and converts the tilt angle into a correction amount along the X-axis and a correction amount along the Y-axis.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The anti-shake function of the periscope optical system is achieved by translating a single anti-shake lens, and the anti-shake lens is made of plastic, which is beneficial to reducing the power consumption of the anti-shake mechanism, improving reliability, and also helping to reduce the volume of the anti-shake mechanism, thereby reducing the size of the periscope optical system;

[0024] (2) Both the front lens and the anti-shake lens have positive focal length, which can converge light, which is conducive to reducing the aperture of the lens group, thereby reducing the size of the periscope optical system and lowering the height of the camera module;

[0025] (3) The lenses in the lens group are all made of plastic, which helps to reduce the weight of the periscope optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the anti-shake principle of an existing periscope optical system using a lens group translation method;

[0027] Figure 2 This is a schematic diagram of the anti-shake principle of an existing periscope optical system using a prism rotation method;

[0028] Figure 3 is a schematic diagram of the anti-shake principle of the periscope optical system according to the present application;

[0029] Figure 4A is a schematic structural diagram of a periscope optical system according to the present application;

[0030] Figure 4B is a schematic diagram of the optical path of the periscope optical system according to the present application;

[0031] Figure 5A Schematic diagram of the optical path of the periscope optical system before anti-shake correction according to the present application;

[0032] Figure 5B Schematic diagram of the optical path after anti-shake correction of the periscope optical system according to the present application;

[0033] Figure 6 This is a schematic diagram of the position of the center of the image point on the imaging surface before anti-shake correction.

[0034] In the figure: 10, front lens; 20, light deflection element; 30, lens group; 40, filter; 50, imaging surface; 60, anti-shake lens. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0036] In the description of the present invention, it should be noted that, for directional words, such as the terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating directions and positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present invention.

[0037] It should be noted that the terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0038] The terms "comprises" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, product or apparatus.

[0039] Traditional periscope optical systems usually use the following two types of structures for anti-shake. Figure 1 and Figure 2As shown, the light deflection element 20 is a prism, which is disposed on the object side of the lens assembly 30, and the imaging surface 50 is disposed on the image side of the lens assembly 30. The prism has a reflective surface, which can deflect light from the first optical axis AX1 to the second optical axis AX2, allowing the light to pass through the lens assembly 30 located on the second optical axis AX2 and form an image on the imaging surface 50. Typically, the first optical axis AX1 is perpendicular to the second optical axis AX2, the Z axis is parallel to the second optical axis AX2, the X axis is parallel to the first optical axis AX1, and the Y axis is perpendicular to the plane formed by the X and Z axes. The specific anti-shake method is as follows:

[0040] (1) Lens group translation method: Figure 1 As shown, when vibration of the periscope optical system is detected, the lens group 30 is driven to translate along the X-axis and / or the Y-axis. However, in a periscope optical system, the longer the focal length, the greater the translation stroke required for the lens group 30 to achieve the anti-shake function. This leads to problems such as complex motor configuration, increased power consumption, and reduced mechanical reliability required to drive the lens group 30 translation.

[0041] (2) Prism rotation method: Figure 2 As shown, when vibration of the periscope optical system is detected, the prism is driven to rotate about the Y-axis and / or the Z-axis. However, this method generates a rotational component, causing the calibrated image center to be offset relative to the second optical axis AX2, resulting in poor anti-shake reliability. Furthermore, in a periscope optical system, a larger image plane and a larger aperture require a larger prism, which in turn increases the power consumption of the motor driving the prism. This can easily lead to problems such as complex anti-shake mechanism design, slow response, and excessive overall size of the camera module housing the periscope optical system.

[0042] Based on the above content, the present application provides a periscope optical system, such as Figure 3-5B As shown, the periscope optical system includes a lens assembly 30 and a light deflection element 20 located on the object side of the lens assembly 30. The light deflection element 20 is used to deflect light from the first optical axis AX1 to the second optical axis AX2 so that it can pass through the lens assembly 30. The periscope optical system also includes an anti-shake lens 60 and an anti-shake mechanism. The anti-shake lens 60 has positive optical power and is located between the light deflection element 20 and the lens assembly 30. The anti-shake mechanism is used to drive the anti-shake lens 60 to translate in a plane perpendicular to the second optical axis AX2 to correct the shake of the periscope optical system.

[0043] Specifically, when the periscope optical system is stable, the light deflection element 20 redirects light from the first optical axis AX1 to the second optical axis AX2. The first optical axis AX1 is perpendicular to the light incident surface of the light deflection element 20, the second optical axis AX2 is perpendicular to the light exit surface of the light deflection element 20, and the second optical axis AX2 coincides with the optical axis of the lens assembly 30. Light incident along the first optical axis AX1 passes through the light incident surface, deflects to the second optical axis AX2, then exits from the light exit surface and is projected onto the lens assembly 30, ultimately arriving at the imaging surface 50 on the image side of the lens assembly 30 for formation.

[0044] When the periscope optical system shakes, the anti-shake lens 60 translates in a plane perpendicular to the second optical axis AX2. Compared with achieving anti-shake function by driving the prism to rotate or driving the lens group 30 to translate, the anti-shake lens 60 of the present application is smaller in size and lighter in weight. While correcting the shake of the periscope optical system, it is able to reduce the load and power consumption of the motor and improve the reliability and response speed of the motor.

[0045] It is understood that the driving force of a motor is generally positively correlated with its size. The greater the driving force, the larger the overall size of the motor. Therefore, in this application, anti-shake is achieved by driving the relatively lightweight anti-shake lens 60 in translation. This reduces the size of the motor, which also helps to reduce the design difficulty and volume of the anti-shake mechanism, thereby helping to reduce the size of the periscope optical system. Preferably, the anti-shake lens 60 is made of plastic to further reduce its weight.

[0046] Moreover, compared to achieving anti-shake function by driving the prism to rotate, the light deflection element 20 of the present application is fixed, and anti-shake is achieved only by driving the anti-shake lens 60 to translate in a plane perpendicular to the second optical axis AX2, thereby avoiding the generation of additional rotational components during the anti-shake process, thereby reducing the impact on the imaging position and improving the imaging quality, which is conducive to further improving the reliability of the anti-shake function of the periscope optical system.

[0047] It is worth mentioning that the anti-shake lens 60 has a positive optical focal length, which enables the light emitted from the light deflection element 20 to be further converged and then projected onto the lens group 30, which is beneficial to reducing the aperture of the lens group 30, thereby reducing the overall size of the periscope optical system, and helping to reduce the shoulder height of the camera module equipped with the periscope optical system.

[0048] In an alternative embodiment, if Figure 3 and Figure 4AAs shown, the light deflection element 20 is a prism, with its light-entry and light-exit surfaces perpendicular to each other. The prism also has a reflective surface that deflects light 90°. The front lens 10 is positioned on the object side of the prism, while the anti-shake lens 60 and the lens assembly 30 are positioned sequentially on the image side of the prism. It is understood that the prism must cover the entire field of view of the periscope optical system. In other words, the movable travel of the anti-shake lens 60 is entirely within the projection area of ​​the prism. That is, the projection area of ​​the prism on the plane where the anti-shake lens 60 lies covers the travel range of the anti-shake lens 60. This ensures that the anti-shake lens 60 receives all light emitted from the prism while translating within its movable travel, thereby avoiding reducing the image area and shrinking the frame. Therefore, it is understood that, in the direction perpendicular to the optical axis, the prism is larger than the anti-shake lens 60 and the lens assembly 30, resulting in the prism being a convex portion of the periscope optical system. Through the structural coordination of the prism and the anti-shake lens 60, the overall size of the periscope optical system can be made more compact while satisfying the anti-shake function.

[0049] Specifically, when the periscope optical system is stable, the optical axis of the anti-shake lens 60 coincides with the optical axis of the light-emitting surface of the prism. When the periscope optical system is vibrating, the maximum travel of the anti-shake lens 60 in the X-axis direction is referred to as the X-displacement dimension, and the maximum travel of the anti-shake lens 60 in the Y-axis direction is referred to as the Y-displacement dimension. Both the X-displacement dimension and the Y-displacement dimension should be less than or equal to the size of the prism's projection area in the XY plane. In other words, while the size of the anti-shake lens 60 remains unchanged, the prism's size can be adjusted so that the prism's projection area in the XY plane only covers the maximum range of motion of the anti-shake lens 60 in the XY plane, thereby reducing the size of the prism.

[0050] In an alternative embodiment, if Figure 3 As shown, the first optical axis AX1 and the second optical axis AX2 are perpendicular to each other, and the anti-shake lens 60 is suitable for translating in a plane perpendicular to the optical axis AX2 and in a direction parallel to the first optical axis AX1, and / or the anti-shake lens 60 is suitable for translating in a plane perpendicular to the optical axis AX2 and in a direction perpendicular to the first optical axis AX1.

[0051] Specifically, the Z axis is set to coincide with the second optical axis AX2, the X axis is parallel to the first optical axis AX1, and the Y axis is perpendicular to the plane formed by the X and Z axes. The anti-shake lens 60 is located in the XY plane formed by the X and Y axes. When the periscope optical system is not shaking, the anti-shake lens 60 is not driven by the anti-shake mechanism. At this time, the optical axis of the anti-shake lens 60 coincides with the Z axis, that is, the optical axis of the anti-shake lens 60 coincides with the optical axis of the lens group 30.

[0052] When the periscope optical system shakes, the anti-shake lens 60 is driven by the anti-shake mechanism to translate along the X-axis and / or along the Y-axis within the displacement plane, which is beneficial for decomposing the light offset on the displacement plane into two components along the X-axis and along the Y-axis. Then, by driving the anti-shake lens 60 to translate the corresponding displacement amounts in the X-axis and Y-axis directions, the light offset components along the X-axis and along the Y-axis are corrected respectively, which is beneficial for controlling the displacement amount of the anti-shake lens 60, thereby improving the controllability and reliability of the anti-shake function of the periscope optical system.

[0053] In some embodiments, as Figure 3 and Figure 4A As shown, the periscope optical system also includes a front lens 10 with positive optical power. The object side of the front lens 10 is convex, and the image side is concave. The object side radius of curvature of the front lens 10 is smaller than the image side radius of curvature of the front lens 10. The front lens 10 is located on the object side of the light deflection element 20 to converge the light. In other words, the light is converged by the front lens 10 before entering the light deflection element 20. This reduces the required aperture of the anti-shake lens 60 and the lens assembly 30, and also reduces the displacement required by the anti-shake lens 60 to correct the shake of the periscope optical system. This reduces the impact of the displacement of the anti-shake lens 60 on the overall size of the periscope optical system, which helps to reduce the shoulder height of the camera module equipped with the periscope optical system.

[0054] Furthermore, the effective focal length of the periscope optical system is EFL X , the effective focal length of the front lens 10 is EFL Q , satisfying the following relationship: 2.71<(EFL X / EFL Q )<4.45. Furthermore, the object side curvature radius of the front lens 10 is less than 100 mm, the object side curvature radius of the front lens 10 is less than 150 mm, and the EFL Q <100mm. This is beneficial for converging light, thereby reducing the diameter of the anti-shake lens 60 and the lens group 30.

[0055] In an optional embodiment, the anti-shake mechanism is arranged on both sides of the anti-shake lens 60 along the Y-axis direction, so as to reduce the impact on the size of the periscope optical system along the X-axis direction, so that the structure of the periscope optical system is more compact, which is conducive to reducing the shoulder height of the camera module loaded with the periscope optical system.

[0056] In some embodiments, the center thickness of the anti-shake lens 60 is TC F , satisfying the following relationship: 0.96mm <TC F <2.4mm, it can be understood that the anti-shake lens 60 has positive focal length, when 0.96mm <TC FWhen the diameter of the lens element is less than 2.4 mm, the volume and weight of the anti-shake lens 60 can be reduced while ensuring the focusing effect and reducing the aperture of the lens group 30. This allows the anti-shake lens 60 to have both a good focusing effect and a smaller size, thereby reducing the size of the motor and the anti-shake mechanism, which is beneficial to reducing the overall size of the periscope optical system and reducing manufacturing costs.

[0057] Furthermore, the center thickness of the anti-shake lens 60 is TC F , the effective focal length of the periscope optical system is EFL X , satisfying the following relationship: 0.043<(TC F / EFL X ) < 0.107. It is understandable that the anti-shake lens 60 is smaller than the entire periscope optical system, but it is able to share the greater sensitivity of the periscope optical system. In other words, the anti-shake lens 60 can achieve a larger displacement of the imaging plane with a shorter displacement stroke.

[0058] Furthermore, the edge thickness of the anti-shake lens 60 is TE F , satisfying the following relationship: 0.4mm <TE F <1mm, 1<(TC F / TE F ) < 2.4. While ensuring high processability of the anti-shake lens 60, the volume of the anti-shake lens 60 is reduced, thereby reducing the weight of the anti-shake lens 60. This helps reduce the size of the motor required to drive the translation of the anti-shake lens 60, thereby reducing the design difficulty and volume of the anti-shake mechanism, and thus helping to reduce the overall size of the periscope optical system.

[0059] In some embodiments, the effective aperture of the anti-shake lens 60 is D F , the effective focal length of the periscope optical system is EFL X , the entrance pupil diameter of the periscope optical system is EPD X , satisfying the following relationship: (D F / EFL X )>0.17, (D F / EPD X )>0.418. It can be understood that the effective focal length EFL of the periscope optical system X And the entrance pupil diameter EPD of the periscope optical system X , are proportional to the maximum travel of the anti-shake lens 60 in the XY plane. When the effective aperture D of the anti-shake lens 60 F Satisfaction (D F / EFL X )>0.17, (D F / EPD X)>0.418, so that when the anti-shake lens 60 translates in the XY plane, the light aperture of the anti-shake lens 60 is still within the effective aperture of the anti-shake lens 60, which is beneficial to ensuring the imaging quality of the periscope optical system.

[0060] In some embodiments, the effective focal length of the anti-shake lens 60 is EFL F , the effective focal length of the periscope optical system is EFL X , satisfying the following relationship: EFL F <EFL X When the periscope optical system shakes, the anti-shake lens 60 has sufficient refractive power to refract the offset light, so that the light convergence effect is better, which is beneficial to correct the shake of the periscope optical system.

[0061] Preferably, the effective focal length EFL of the periscope optical system is X and the effective focal length EFL of the image stabilization lens 60 F , satisfying the following relationship: 1<(EFL X / EFL F ) < 1.55, enabling the anti-shake lens 60 to have a longer focal length, thereby improving the anti-shake effect of the periscope optical system. It is understandable that periscope optical systems typically have a longer focal length, and therefore require a relatively large number of lenses to correct optical issues such as jitter that occur within the focal range. A longer focal length of the anti-shake lens 60 is beneficial for improving the anti-shake effect of the anti-shake lens 60 within a unit of travel.

[0062] In some embodiments, the minimum gap between the anti-shake lens 60 and the light deflection element 20 is H1, and the minimum gap between the anti-shake lens 60 and the lens group 30 is H2, satisfying the following relationship: (H1 / H2)≥2. The gap between the anti-shake lens 60 and the light deflection element 20 is able to avoid the anti-shake mechanism, so that the anti-shake mechanism is set close to the light deflection element 20, thereby making the structure of the periscope optical system more compact.

[0063] It can be understood that when the light deflection element 20 is a prism, the driving end of the anti-shake mechanism installed on the anti-shake lens 60 is arranged close to the prism and the front lens 10. Since the prism and the front lens 10 are relatively large in size, the anti-shake mechanism is arranged on a part of the anti-shake lens 60 that is smaller than the prism. In other words, it is best to avoid making the size of the anti-shake mechanism larger than the size of the prism that exceeds the anti-shake lens 60, which is beneficial to avoid the anti-shake mechanism from increasing the size of the periscope optical system.

[0064] Preferably, the minimum gap H1 between the anti-shake lens 60 and the light redirecting element 20 is greater than 0.6 mm, and the minimum gap H2 between the anti-shake lens 60 and the lens group 30 is greater than 0.3 mm. This reduces the risk of collision between the anti-shake lens 60 and the light redirecting element 20, as well as the risk of collision between the anti-shake lens 60 and the lens group 30, thereby preventing damage to the anti-shake lens 60 and improving the reliability of the periscope optical system. In an optional embodiment, the minimum gap between the anti-shake lens 60 and the light redirecting element 20 is greater than the center thickness TC of the anti-shake lens 60. F , so that the anti-shake lens 60 can maintain good optical performance.

[0065] In some embodiments, the center thickness of the anti-shake lens 60 is TC F The effective aperture of the anti-shake lens 60 is D F , satisfying the following relationship: 5<((D F +0.05)×2 / TC F )<11, where ((D F +0.05)×2 / TC F ) is calculated as the outer diameter-to-thickness ratio of the anti-shake lens 60, which makes the structure of the periscope optical system more compact while ensuring the high machinability of the anti-shake lens 60, and is conducive to reducing the shoulder height of the camera module equipped with the periscope optical system.

[0066] In some embodiments, the object-side surface of the anti-shake lens 60 is a 14th to 20th order aspheric surface with a positive radius of curvature; the image-side surface of the anti-shake lens 60 is a 14th to 20th order aspheric surface with a negative radius of curvature. It is understood that the use of aspheric surfaces on both the object-side and image-side surfaces of the anti-shake lens 60 reduces the spherical aberration of the periscope optical system, thereby improving the final image quality. Furthermore, the positive radius of curvature of the object-side surface of the anti-shake lens 60 and the negative radius of curvature of the image-side surface indicate that the anti-shake lens 60 is a biconvex lens, which deflects light in the same direction through both the object-side and image-side surfaces, resulting in better light convergence and improving the anti-shake effect within the unit travel of the anti-shake lens 60.

[0067] In some embodiments, as Figures 4A-5B As shown, the lens assembly 30 includes at least five lenses, which are capable of imaging the light corrected by the anti-shake lens 60 onto the imaging surface 50 located on the image side of the lens assembly 30. Furthermore, the lenses in the lens assembly 30 are all made of plastic, which can reduce the weight of the lens assembly 30, thereby reducing the weight of the periscope optical system and the total weight of the camera module equipped with the periscope optical system.

[0068] Furthermore, a filter 40 for cutting off stray light is provided between the image side of the lens assembly 30 and the imaging surface 50, thereby further improving the imaging quality. Preferably, an infrared cut-off filter is used to improve the brightness and color reproduction of the final image.

[0069] <Example 1>

[0070] Figure 4A and Figure 4B An embodiment of the periscope optical system of the present application is presented. In this embodiment, the periscope optical system includes, from the object side to the image side, the following: a front lens 10 with orthogonal luminosity, for focusing light; a prism with total reflection capability, for turning light from the first optical axis AX1 to the second optical axis AX2; an anti-shake lens 60 that translates in the XY plane perpendicular to the second optical axis AX2 to correct the shake of the periscope optical system; an aperture, for adjusting the intensity of light; and a lens group, for imaging the light corrected by the anti-shake lens 60 onto an imaging surface 50 located on the image side of the lens group 30.

[0071] Among them, the focal length of the periscope optical system is EFL, the aperture value is FNO, the maximum viewing angle is FOV, the half image height is H, the diameter of the maximum imaging circle is MIC, and the pixel size is Pixelsize. The specific parameter values ​​are as follows: EFL = 22.46mm, FOV = 28.34mm, FNO = 2.35, half image height = 5.72mm, MIC = 12.36mm, Pixelsize = 0.56um.

[0072] It will be appreciated that in this embodiment, the light deflecting element 20 is a prism with total internal reflection capability. The prism has an incident surface and an exit surface, and the incident and exit surfaces are perpendicular to each other, that is, the first optical axis AX1 and the second optical axis AX2 are orthogonal. The prism also has a reflective surface, and the reflective surface forms an angle of 45° with the first optical axis AX1. This allows light entering the prism from the incident surface to be deflected 90° by the reflective surface before exiting the exit surface.

[0073] Furthermore, in the present embodiment, the total length of the lens group 30 is 10.9 mm, and the maximum semi-aperture is 3.79 mm. Specifically, the lens group 30 includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens in order from the object side to the image side. The focal length EFL1 of the first lens is a positive focal length, the object side surface is a convex surface, and the image side surface is a concave surface, which is used to converge the incident light, thereby narrowing the range of the light, and thus helping to reduce the size of the periscope optical system. Preferably, EFL1 = 127.2 mm; the focal length EFL2 of the second lens is a negative focal length, the object side surface is a convex surface, and the image side surface is a concave surface, which is used to correct primary and secondary spherical aberrations. Preferably, EFL2 = -9.17 mm; the focal length EFL3 of the third lens is a positive focal length, the object side surface is a convex surface, and the image side surface is a concave surface. , the image side surface is convex, which is used to correct astigmatism, preferably, EFL3=8.8mm; the fourth lens focal length EFL4 is a positive focal length, the object side surface is concave, and the image side surface is convex, which is used to correct coma, primary astigmatism and distortion, preferably, EFL4=82.8mm; the fifth lens focal length EFL5 is a negative focal length, the object side surface is convex at the near axis, and the image side surface is concave at the near axis, preferably, EFL5=-15.22mm, and the minimum gap between the fifth lens and the imaging surface 50 is greater than 4mm.

[0074] In this embodiment, the first, second, and third lenses are fixed relative to the imaging plane 50, while the fourth and fifth lenses are adapted to translate together relative to the imaging plane 50 to achieve focusing of the periscope optical system. It will be appreciated that, compared to moving the lens assembly 30 to achieve focusing of the periscope optical system, this embodiment utilizes the method of moving the fourth and fifth lenses to achieve focusing, thereby reducing the driving force required to drive the motor, thereby reducing the size of the motor and facilitating a reduction in the overall size of the periscope optical system.

[0075] Table 1 below shows the optical parameters of each optical element of this embodiment, including refractive index Nd, dispersion coefficient Vd and material, where

[0076] Table 1 Optical parameters of each optical element in Example 1

[0077] A method for driving an anti-shake mechanism, applied to the aforementioned periscope optical system, comprises the following steps: a. setting a displacement plane, the displacement plane being perpendicular to the second optical axis AX2 and having mutually orthogonal X-axis and Y-axis; b. obtaining an anti-shake signal from the periscope optical system and converting it into a correction amount along the X-axis and a correction amount along the Y-axis; and c. driving the anti-shake mechanism to translate the anti-shake lens 60 along the X-axis and / or Y-axis within the displacement plane according to the correction amount to correct the shake of the periscope optical system.

[0078] It is understandable that compared with the prism and lens group 30, the single anti-shake lens 60 is smaller in size and lighter in weight. By driving the anti-shake lens 60 to translate within the displacement plane according to the correction amount, it is possible to reduce the load and power consumption of the motor while achieving the anti-shake function, improve the response speed, and also help to reduce the design difficulty of the anti-shake mechanism.

[0079] In addition, compared with rotating the prism to achieve the anti-shake function, the displacement plane is perpendicular to the second optical axis AX2, that is, the optical axis of the lens group 30. The anti-shake function is completely achieved by the translation of the anti-shake lens 60 within the displacement plane, which can avoid the generation of additional rotation components in the process of correcting the shake of the periscope optical system, which is beneficial to reduce the impact on the position of the final image, thereby improving the image quality.

[0080] In an optional embodiment, the first optical axis AX1 and the second optical axis AX2 are perpendicular to each other. Step a specifically includes setting a displacement plane perpendicular to the second optical axis AX2, wherein the displacement plane has an X-axis parallel to the first optical axis AX2 and a Y-axis perpendicular to the X-axis. Step b specifically includes detecting the jitter of the periscope optical system using a gyroscope, converting the jitter into an anti-shake signal and feeding it back to the micro-control unit. The micro-control unit calculates the tilt angle caused by the jitter based on the anti-shake signal and converts the tilt angle into a correction amount along the X-axis and a correction amount along the Y-axis. Step c specifically includes the anti-shake mechanism driving the anti-shake lens 60 to translate along the X-axis direction within the displacement plane based on the correction amount along the X-axis direction, and / or the anti-shake mechanism driving the anti-shake lens 60 to translate along the Y-axis direction within the displacement plane based on the correction amount along the Y-axis direction.

[0081] It can be understood that the displacement plane is perpendicular to the second optical axis AX2, and the anti-shake lens 60 is driven by the anti-shake mechanism to translate along the X-axis and / or along the Y-axis within the displacement plane. Through the orthogonal X-axis and Y-axis, it is beneficial to decompose the offset of the light on the displacement plane into two components along the X-axis direction and along the Y-axis direction, thereby facilitating the controllability of the anti-shake function of the periscope optical system.

[0082] <Example 2>

[0083] Figure 5A and Figure 5B An embodiment of the periscope optical system correction of the present application is presented.

[0084] When it is detected that the object is relatively perpendicular to the second optical axis AX2 along the plane Figure 5A When the direction shown is offset and rotated by 1°, the position of the final image point center on the object side plane of the imaging surface 50 is offset on the X axis relative to the intersection of the second optical axis AX2 and the imaging surface 50, as shown in FIG. Figure 6As shown. Through the above anti-shake mechanism driving method, as shown Figure 5B As shown, the anti-shake mechanism drives the anti-shake lens 60 to translate 0.5 mm along the X-axis direction, so that the center of the final image point is corrected to the intersection of the second optical axis AX2 and the imaging surface 50, thereby realizing the anti-shake function of the periscope camera module.

[0085] The above describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and description merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A periscope optical system comprising a lens assembly and a light deflecting element located on an object side of the lens assembly, wherein the light deflecting element is configured to deflect light from a first optical axis AX1 to a second optical axis AX2 to pass through the lens assembly, wherein: Also includes: an anti-shake lens having positive optical power, the anti-shake lens being located between the light deflecting element and the lens group, the anti-shake lens being adapted to translate in a plane perpendicular to the second optical axis AX2; An anti-shake mechanism is used to drive the anti-shake lens to translate to correct the shake of the periscope optical system.

2. The periscope optical system according to claim 1, wherein: The first optical axis AX1 and the second optical axis AX2 are perpendicular to each other, and the anti-shake lens is suitable for translating in a direction parallel to the first optical axis AX1 within a plane perpendicular to the optical axis AX2, and / or the anti-shake lens is suitable for translating in a direction perpendicular to the first optical axis AX1 within a plane perpendicular to the optical axis AX2.

3. The periscope optical system according to claim 1 or 2, characterized in that: The center thickness of the anti-shake lens is TC F , satisfying the following relationship: 0.96mm <TC F <2.4mm.

4. The periscope optical system according to claim 3, wherein: The center thickness of the anti-shake lens is TC F , the effective focal length of the periscope optical system is EFL X , satisfying the following relationship: 0.043<(TC F / EFL X )<0.

107.

5. The periscope optical system according to claim 1 or 2, characterized in that: The effective aperture of the anti-shake lens is D F , the effective focal length of the periscope optical system is EFL X , the entrance pupil diameter of the periscope optical system is EPD X , satisfying the following relationship: (D F / EFL X )>0.17, (D F / EPD X )>0.

418.

6. The periscope optical system according to claim 1 or 2, characterized in that: The effective focal length of the periscope optical system is EFL X The effective focal length of the anti-shake lens is EFL F , satisfying the following relationship: 1<(EFL X / EFL F )<1.

55.

7. The periscope optical system according to claim 1 or 2, characterized in that: The minimum gap between the anti-shake lens and the light deflection element is H1, and the minimum gap between the anti-shake lens and the lens group is H2, satisfying the following relationship: (H1 / H2)≥2.

8. The periscope optical system according to claim 1 or 2, characterized in that: The minimum gap between the anti-shake lens and the light deflection element is greater than the center thickness TC of the anti-shake lens F .

9. The periscope optical system according to claim 1 or 2, characterized in that: It also includes a front lens with positive optical power, the object side of the front lens is convex, the image side is concave, and the object side curvature radius of the front lens is smaller than the image side curvature radius of the front lens. The front lens is located on the object side of the light deflecting element to converge the light.

10. The periscope optical system according to claim 9, characterized in that: The effective focal length of the periscope optical system is EFL X , the effective focal length of the front lens is EFL Q , satisfying the following relationship: 2.71<(EFL X / EFL Q )<4.

45.

11. The periscope optical system according to claim 1 or 2, characterized in that: The lens group includes at least five lenses, and the at least five lenses include: The first lens has a positive focal length, a convex object-side surface, and a concave image-side surface; The second lens has a negative focal length, its object side is convex, and its image side is concave; The third lens has a positive focal length, and its object-side surface is convex, and its image-side surface is convex; The fourth lens has a positive focal length, a concave object-side surface, and a convex image-side surface; The fifth lens has a negative focal length, its object side surface is convex, and its image side surface is concave; Wherein, the anti-shake lens and the lenses in the lens group are all made of plastic.

12. The periscope optical system according to claim 1 or 2, characterized in that: The center thickness of the anti-shake lens is TC F The effective aperture of the anti-shake lens is D F , satisfying the following relationship: 5<((D F +0.05)×2 / TC F )<11.

13. A method for driving an anti-shake mechanism, applied to the periscope optical system according to any one of claims 1 to 12, characterized in that: Including steps: a. Setting a displacement plane, wherein the displacement plane is perpendicular to the second optical axis AX2 and has an X-axis and a Y-axis that are orthogonal to each other; b. Obtaining an anti-shake signal of the periscope optical system and converting it into a correction amount along the X-axis and a correction amount along the Y-axis; c. The anti-shake mechanism drives the anti-shake lens to translate along the X-axis and / or the Y-axis in the displacement plane according to the correction amount to correct the shake of the periscope optical system.

14. The anti-shake mechanism driving method according to claim 13, wherein: Step b specifically includes detecting the jitter of the periscope optical system through a gyroscope, and converting the jitter into the anti-shake signal and feeding it back to the micro-control unit. The micro-control unit calculates the tilt angle caused by the jitter based on the anti-shake signal, and converts the tilt angle into a correction amount along the X-axis and a correction amount along the Y-axis.

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