Optical lens, camera, and electronic device

Abstract

An optical lens (101), a camera, and an electronic device, having the characteristics of miniaturization, low cost, high imaging performance, and high thermal stability. The optical lens (101) comprises four lens groups. A relatively small amount of lens groups are used while it is ensured that the function of the optical lens (101) is implemented, thereby facilitating miniaturization. At least one lens group in the optical lens (101) comprises an even number of aspheric plastic lenses. On one hand, use of some aspheric plastic lenses can ensure good imaging quality while reducing costs; and on the other hand, design of an even number of aspheric plastic lenses in the same lens group helps to improve the thermal stability of the optical lens (101), that is, the impact of the ambient temperature on imaging quality is reduced, and good imaging can be ensured in an environment of -30°C to 70°C.

Description

Optical lens, camera and electronic device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on January 18, 2024, with application number 202410079653.7 and application name “An optical lens, camera and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical imaging, and in particular to an optical lens, a camera, and an electronic device. Background Art

[0003] As a window for information input, surveillance cameras play an irreplaceable role in smart transportation, smart homes, and smart security. In particular, in open environments, to capture all aspects of a large scene, rotating and zooming dome cameras are required for filming and tracking. Dome cameras integrate pan / tilt systems, communication systems, and camera systems, including motor control, image transmission, and recording, and are generally large and heavy.

[0004] Furthermore, the demand for higher resolution and higher zoom lenses has been increasing in recent years, resulting in a larger and larger proportion of the lens space being occupied. This has further increased the weight of dome cameras, hindering their miniaturization and cost control. Therefore, there is an urgent need for a lens that combines miniaturization, low cost, high imaging performance, and high thermal stability.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide an optical lens, a camera, and an electronic device that have the characteristics of miniaturization, low cost, high imaging performance, and high thermal stability.

[0007] In a first aspect, an embodiment of the present application provides an optical lens, comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged along an optical axis from the object side to the image side. The first lens group and the third lens group are fixed in position, and the second lens group and the fourth lens group are movable along the optical axis. The first lens group, the third lens group, and the fourth lens group have positive optical power, and the second lens group has negative optical power. At least one lens group in the optical lens includes an even number of aspherical plastic lenses.

[0008] In this embodiment, the optical lens includes four lens groups. While ensuring the functionality of the optical lens, a relatively small number of lens groups are used, facilitating miniaturization. At least one lens group in the optical lens includes an even number of aspheric plastic lenses. On the one hand, the use of some aspheric plastic lenses reduces costs while ensuring good imaging quality. On the other hand, designing an even number of aspheric plastic lenses in the same lens group helps improve the thermal stability of the optical lens, thereby reducing the impact of ambient temperature on imaging quality and ensuring good imaging in an environment of -30°C to 70°C.

[0009] In some possible implementations, taking two aspherical plastic lenses in a pair in the same lens group as an example, the signs of the optical powers of these two aspherical plastic lenses are opposite, and further, the absolute values ​​of the optical powers of these two aspherical plastic lenses are close to or equal. In this way, the total optical power of the lens group remains as constant as possible as the temperature changes, thereby helping to reduce the impact of ambient temperature on the stability of lens performance and further improve the thermal stability of the entire lens. For example, these two aspherical plastic lenses are respectively recorded as the first aspherical plastic lens and the second aspherical plastic lens. represents the optical power of the first aspherical plastic lens, Represents the optical power of the second aspherical plastic lens, then In one possible scenario, Right now In another possible scenario, The two aspherical plastic lenses with a larger absolute value of optical focal length are recorded as the first aspherical plastic lens, and the one with a smaller absolute value of optical focal length is recorded as the second aspherical plastic lens. It should be understood that the present application does not limit the specific value of the preset value. In practical applications, the preset value can be flexibly set according to actual needs. For example, the preset value is 5, that is, It is considered that the absolute values ​​of the optical powers of the two aspherical plastic lenses are close to or equal.

[0010] In some possible implementations, each lens group in the optical lens includes at least one glass lens, which is beneficial for improving the zoom capability, imaging quality and thermal stability of the optical lens.

[0011] In some possible implementations, each glass lens in the optical lens is a glass spherical lens, which can appropriately reduce costs compared to using a glass aspherical lens.

[0012] In some possible implementations, the optical lens further includes a fixed aperture stop located between the second lens group and the third lens group. The diameter of the aperture stop is adjustable to facilitate flexible adjustment of the aperture size of the optical lens.

[0013] In some possible implementations, the minimum distance between the aperture stop and the second lens group is greater than or equal to 0.5 mm, and the distance between the aperture stop and the third lens group is greater than or equal to 0.5 mm. In other words, a certain distance is maintained between the aperture stop and both the second and third lens groups, allowing the second lens group to have a certain positional margin during movement, facilitating control of the movement stroke and avoiding collision with the aperture stop.

[0014] In some possible implementations, the optical lens satisfies the following relationship: -0.5 < f2 / f1 < 0, 0 < f3 / f1 < 1, and 0.5 < f4 / f1 < 1. Here, f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, f3 represents the focal length of the third lens group, and f4 represents the focal length of the fourth lens group. This design enables the optical lens to have excellent zoom capability and imaging quality.

[0015] In some possible implementations, the first lens group includes two aspherical plastic lenses, the second lens group includes two aspherical plastic lenses, and the third lens group includes two aspherical plastic lenses. A specific embodiment of a paired aspherical plastic lens arrangement is provided herein, which combines the advantages of miniaturization, low cost, high imaging performance, and high thermal stability.

[0016] In some possible embodiments, the first lens group includes lens 1-1, lens 1-2, lens 1-3, lens 1-4, and lens 1-5; the second lens group includes lens 2-1, lens 2-2, and lens 2-3; the third lens group includes lens 3-1, lens 3-2, and lens 3-3; and the fourth lens group includes lens 4-1, lens 4-2, and lens 4-3. Lens 1-1, lens 1-2, lens 1-4, lens 2-1, lens 3-2, lens 4-1, lens 4-2, and lens 4-3 are spherical glass lenses. Lens 1-3, lens 1-5, lens 2-2, lens 2-3, lens 3-1, and lens 3-3 are aspherical plastic lenses. A specific design method for each lens group in an optical lens is provided herein, which has good practical effects.

[0017] In some possible implementations, the second lens group includes two aspherical plastic lenses, the third lens group includes two aspherical plastic lenses, and the fourth lens group includes two aspherical plastic lenses. Another specific embodiment of a paired aspherical plastic lens arrangement is provided herein, combining miniaturization, low cost, high imaging performance, and high thermal stability.

[0018] In some possible implementations, the first lens group includes lens 1-1, lens 1-2, lens 1-3, lens 1-4, and lens 1-5; the second lens group includes lens 2-1, lens 2-2, and lens 2-3; the third lens group includes lens 3-1, lens 3-2, and lens 3-3; and the fourth lens group includes lens 4-1, lens 4-2, and lens 4-3. Lenses 1-1, lens 1-2, lens 1-3, lens 1-4, lens 1-5, lens 2-1, lens 3-2, and lens 4-2 are spherical glass lenses. Lenses 2-2, lens 2-3, lens 3-1, lens 3-3, lens 4-1, and lens 4-3 are aspherical plastic lenses. Another specific design method for each lens group in an optical lens is provided herein, enriching the implementation methods of this solution.

[0019] In some possible implementations, the second lens group is used to zoom by moving along the optical axis, and the fourth lens group is used to compensate for the offset of the image plane position by moving along the optical axis. In other words, the fourth lens group is used to move in conjunction with the movement of the second lens group to keep the position of the image plane unchanged, that is, to keep the total optical length of the optical lens unchanged.

[0020] In some possible implementations, as the positions of the second lens group and the fourth lens group move, the focal length of the optical lens changes from 5.5 mm to 129 mm, having good zoom capability.

[0021] In some possible implementations, the first lens group has the largest aperture in the optical lens, which is conducive to achieving a large field of view.

[0022] In some possible implementations, the optical lens further includes a protective glass, which is located on a side of the fourth lens group close to the image side, thereby providing good sealing for the optical lens.

[0023] In some possible implementations, the aperture number of the optical lens ranges from 1.6 to 4.8, having a relatively large aperture adjustable range.

[0024] In a second aspect, embodiments of the present application provide a camera. The camera includes a photosensitive element and an optical lens as described in any embodiment of the first aspect. The photosensitive element is located on the image side of the optical lens. The optical lens is used to project a light beam from the object to be photographed onto the photosensitive element, and the photosensitive element is used to convert the light beam into image data.

[0025] In a third aspect, an embodiment of the present application provides an electronic device. The electronic device includes an image processor and the camera described in the second aspect. The image processor is connected to the camera and is configured to acquire image data from the camera and process the image data.

[0026] In the embodiment of the present application, the optical lens includes four lens groups. While ensuring the functionality of the optical lens, a relatively small number of lens groups are used, facilitating miniaturization. At least one lens group in the optical lens includes an even number of aspheric plastic lenses. On the one hand, the use of some aspheric plastic lenses can reduce costs while ensuring good imaging quality. On the other hand, designing an even number of aspheric plastic lenses in the same lens group helps improve the thermal stability of the optical lens, thereby reducing the impact of ambient temperature on imaging quality and ensuring good imaging in an environment of -30°C to 70°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of a ball camera;

[0028] FIG2 is a schematic diagram of a first structural example of an optical lens according to an embodiment of the present application;

[0029] FIG3 is a schematic diagram of a second structure of an optical lens in an embodiment of the present application;

[0030] FIG4 is a schematic diagram of a zoom mode of an optical lens in an embodiment of the present application;

[0031] FIG5 is a schematic structural diagram of a camera according to an embodiment of the present application;

[0032] FIG6 is a schematic structural diagram of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The embodiments of the present application provide an optical lens, a camera, and an electronic device that have the characteristics of miniaturization, low cost, high imaging performance, and high thermal stability.

[0034] It should be noted that the terms "first", "second", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] To facilitate understanding, the technical terms involved in the embodiments of the present application are first explained below.

[0036] Focal power, equal to the difference between the image-side and object-side convergence, characterizes an optical system's ability to deflect light. A lens or lens group with positive focal power, or a lens or lens group with a positive focal length, converges light. A lens or lens group with negative focal power, or a lens or lens group with a negative focal length, diverges light.

[0037] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical system. It refers to the vertical distance from the optical center of a lens or lens group to the focal plane when a scene at infinite distance is formed into a sharp image on the focal plane. For thin lenses, the focal length is the distance from the lens center to the image plane; for thick lenses or lens groups, the focal length is equal to the effective focal length (EFL), which is the distance from the rear principal plane of the lens or lens group to the image plane.

[0038] The object side, with the lens as the boundary, is the side where the scene to be imaged is located.

[0039] The image side is the side where the image of the scene to be imaged is located, with the lens as the boundary.

[0040] The object side is divided by the lens. The side where the object is located is called the object side, and the surface of the lens close to the object side is called the object side.

[0041] The image side, with the lens as the boundary, the side where the image of the object is located is called the image side, and the surface of the lens close to the image side is called the image side.

[0042] The imaging plane is located on the image side of all lenses in the optical lens, and is the plane on which the image is formed after the light passes through each lens in the optical lens in sequence.

[0043] The aperture is a device used to control the amount of light that passes through the lens and enters the photosensitive surface inside the camera body. It is usually inside the lens.

[0044] Aperture number, also known as F-number (Fno), is a relative value calculated by dividing the focal length of a lens by the diameter of its entrance pupil (the inverse of the relative aperture). The smaller the aperture, the more light enters per unit time. A larger aperture reduces the depth of field, blurring the background in photos, similar to the effect of a telephoto lens.

[0045] In optical instruments, the field of view (FOV) is the angle between the two edges of the maximum range through which the image of the measured object can pass, with the lens as the vertex. The field of view determines the visual range of the optical instrument. A larger field of view means a wider field of view and a smaller optical magnification.

[0046] Aberration: The paraxial region of an optical system has the properties of an ideal optical system. The paraxial light emitted from a point on the object intersects the image plane at one point (also known as the paraxial image point). However, the light rays that actually pass through different apertures of the lens are unlikely to intersect perfectly at one point. Instead, there is a certain deviation from the position of the paraxial image point. These differences are collectively called aberrations.

[0047] The optical axis is a ray of light that passes perpendicularly through the center of an ideal lens. When light rays parallel to the optical axis enter a convex lens, all rays converge at a single point behind the lens. This point is the focal point. As light rays propagate along the optical axis, their direction of travel remains unchanged.

[0048] The optical lens provided in the embodiment of the present application can be applied to a dome camera for monitoring and identifying a wide range of scenes.

[0049] Figure 1 is a schematic diagram of the structure of a dome camera. A dome camera, also known as a spherical camera, is used to capture video. A dome camera may include a pan / tilt head (PTZ) driven by a stepper motor and a camera mounted on the PTZ. The PTZ is a support device used to secure the camera, and the camera includes an optical lens. The PTZ can rotate horizontally or vertically, and the camera mounted on the PTZ can rotate horizontally or vertically with the PTZ. The focal length of the camera's optical lens is adjustable. By controlling the rotation of the PTZ and adjusting the focal length of the optical lens, the camera's monitoring range can be adjusted. The camera's monitoring range can be considered the camera's visual range or the range of the video it captures.

[0050] It should be understood that the optical lens provided in the embodiments of the present application has a lower cost on the basis of better performance. In this way, by adopting the optical lens provided in the embodiments of the present application, the cost of the ball camera can be effectively reduced. For example, while having the performance of a 6-inch ball camera, the total length of the structure can be shortened to the size of a 5-inch ball camera. In other words, applying the optical lens provided in the embodiments of the present application to a 5-inch ball camera can achieve the performance of the original 6-inch ball camera. This will save the cost of the lens packaging structure while maintaining the high performance of the lens. The cost of the optical lens can be reduced by about 30%, and the cost of the mechanical structure can be reduced by about 40%. The optical lens provided in the embodiments of the present application is introduced in detail below.

[0051] FIG2 is a schematic diagram of the first structure of the optical lens in the embodiment of the present application. As shown in FIG2 , the optical lens comprises lens group 1, lens group 2, lens group 3 and lens group 4 arranged along the optical axis from the object side to the image side. Among them, the positions of lens group 1 and lens group 3 are fixed, lens group 1 is mainly used to correct large field of view aberrations, and lens group 3 mainly plays the role of focusing light and correcting spherical aberrations. Lens group 2 and lens group 4 can move along the direction of the optical axis, lens group 2 zooms by moving along the optical axis, and lens group 4 compensates for the offset of the image plane position by moving along the optical axis to correct various aberrations. In other words, lens group 4 is used to move in coordination with the movement of lens group 2 to keep the position of the image plane unchanged, that is, to keep the total optical length of the optical lens unchanged. For example, the total optical length of the optical lens is 93.3 mm.

[0052] Specifically, lens group 1, lens group 3 and lens group 4 have positive optical focal power, and lens group 2 has negative optical focal power, which is conducive to achieving an ideal zoom ratio. The focal length of lens group 1 is recorded as f1, the focal length of lens group 2 is recorded as f2, the focal length of lens group 3 is recorded as f3, and the focal length of lens group 4 is recorded as f4. As an example, the optical lens satisfies the following relationship: -0.5<f2 / f1<0, 0<f3 / f1<1, 0.5<f4 / f1<1. This design enables the optical lens to have better zoom capability and imaging quality. In some specific scenarios, the central field of view 0F resolution of the optical lens is higher than 1250TVline, and the peripheral 0.7F field of view resolution is higher than 1000TVline.

[0053] In some possible embodiments, the optical lens further includes an aperture stop and a protective glass, wherein the position of the aperture stop is fixed and is located between the lens group 2 and the lens group 3, and the protective glass is located on the side of the lens group 4 close to the image side. The aperture stop can limit the light entering the lens, and the diameter of the aperture stop is adjustable. By adjusting the aperture stop, the aperture size of the optical lens can be changed. For example, the aperture number of the optical lens provided in the embodiment of the present application ranges from 1.6 to 4.8. In practical applications, the aperture stop and the lens group 2 and the lens group 3 must maintain a certain distance so that the lens group 2 has a certain position margin during the movement process, which is convenient for controlling the movement stroke and avoiding collision with the aperture stop. For example, the minimum distance between the aperture stop and the lens group 2 is greater than or equal to 0.5 mm, that is, when the lens group 2 moves to the position closest to the aperture stop, the distance is 0.5 mm, and the distance between the aperture stop and the lens group 3 is greater than or equal to 0.5 mm.

[0054] It should be noted that at least one of the above four lens groups includes an even number of aspheric plastic lenses. This design is mainly based on the following considerations. First, under the premise that the number of lenses remains unchanged, the cost of using some plastic lenses is lower than that of glass lenses. Second, the aberration of imaging using aspheric lenses is smaller than that of spherical lenses, and the imaging quality is better. Third, since the thermal expansion coefficient of plastic materials is larger than that of glass materials, they are more affected by high and low temperature environments. The thermal expansion and contraction of the material itself will also have a greater impact on the lens surface shape and thickness, which will cause the thermal stability of the optical lens to be worse in extreme temperature environments. Therefore, the embodiment of the present application places the aspheric plastic lenses in pairs in the same lens group, which helps to improve the thermal stability of the optical lens, that is, reduces the impact of ambient temperature on imaging quality, and can ensure good imaging in an environment of -30°C to 70°C.

[0055] Alternatively, taking two aspheric plastic lenses in a pair in the same lens group as an example, the signs of the optical powers of the two aspheric plastic lenses are opposite, and further, the absolute values ​​of the optical powers of the two aspheric plastic lenses are close to or equal. In this way, the total optical power of the lens group remains as constant as possible as the temperature changes, thereby reducing the impact of the ambient temperature on the stability of the lens performance and improving the thermal stability of the entire lens. For example, the two aspheric plastic lenses are respectively recorded as the first aspheric plastic lens and the second aspheric plastic lens. represents the optical power of the first aspherical plastic lens, Represents the optical power of the second aspherical plastic lens, then In one possible scenario, Right now In another possible scenario, The two aspherical plastic lenses with a larger absolute value of optical focal length are recorded as the first aspherical plastic lens, and the one with a smaller absolute value of optical focal length is recorded as the second aspherical plastic lens. It should be understood that the present application does not limit the specific value of the preset value. In practical applications, the preset value can be flexibly set according to actual needs. For example, the preset value is 5, that is, It is considered that the absolute values ​​of the optical powers of the two aspherical plastic lenses are close to or equal.

[0056] It should be understood that the embodiments of the present application do not limit the number of lenses in each lens group, nor do they limit which specific lens groups include an even number of aspheric plastic lenses. Typically, lens group 1 is the lens group with the largest aperture in the optical lens, which is conducive to achieving a large field of view. Providing paired aspheric plastic lenses in lens group 1 helps to maximize cost reduction. In addition to the several embodiments provided in this application, other embodiments that can be flexibly transformed by those skilled in the art on this basis are also within the scope of protection of this application.

[0057] It should also be understood that, with the exception of the paired aspheric plastic lenses mentioned above, the materials and types of the other lenses in the optical lens are not limited here. As an example, the other lenses can all be glass lenses, which is beneficial for improving the zoom capability, imaging quality, and thermal stability of the optical lens. For example, a high refractive index glass material can be used to improve the zoom capability. For another example, a low dispersion glass material can be used to reduce the impact of chromatic aberration on imaging quality. Furthermore, the glass lens used can specifically be a glass spherical lens, which can appropriately reduce some costs compared to using a glass aspheric lens.

[0058] Furthermore, when used in low-light environments, the optical lens provided by the present embodiment can image light in the near-infrared band, thereby combining it with visible light to enhance the lens's resolution. In other words, the optical lens provided by the present embodiment can achieve co-focus between the visible and infrared bands, enabling the clear capture of the outline and color information of objects even in dark, low-light environments.

[0059] A specific structural design of an optical lens is introduced below using FIG. 2 as an example. The reference numerals of the lenses in FIG. 2 can refer to the following Table 1.

[0060] Table 1

[0061] Lens group 1 includes two aspherical plastic lenses, lens group 2 includes two aspherical plastic lenses, and lens group 3 includes two aspherical plastic lenses. Specifically, lens 1-1, lens 1-2, lens 1-4, lens 2-1, lens 3-2, lens 4-1, lens 4-2, and lens 4-3 are glass spherical lenses. Lens 1-3, lens 1-5, lens 2-2, lens 2-3, lens 3-1, and lens 3-3 are aspherical plastic lenses. Detailed parameters of each lens in the embodiment shown in Figure 2 are shown in Table 2 below.

[0062] Table 2

[0063] In the embodiment shown in FIG2 , the optical lens includes six aspherical plastic lenses, and the aspherical surface shapes of the aspherical plastic lenses meet the following conditions:

[0064] Where c is the radius of curvature, y is the radial coordinate (in the same units as the lens length), and k is the conic coefficient (conic coefficient). When the conic coefficient is less than -1, the surface shape is a hyperbola; when the conic coefficient is equal to -1, it is a parabola; when the conic coefficient is between -1 and 0, it is an ellipse; when the conic coefficient is equal to 0, it is a circle; and when the conic coefficient is greater than 0, it is an oblate circle. A1, A2, A3, A4, A5, A6, A7, and A8 are high-order aspheric coefficients. These parameters can be used to set the aspheric surface shape of the lens. The aspheric coefficients of each aspheric plastic lens in the embodiment shown in Figure 2 are shown in Table 3 below.

[0065] Table 3

[0066] Figure 3 is a schematic diagram of the second structure of the optical lens in the embodiment of the present application. Different from the optical lens shown in Figure 2 above, Figure 3 shows the specific structural design of another optical lens. Among them, the figure marks of each lens in Figure 3 can still refer to Table 1. Lens group 2 includes two aspherical plastic lenses, lens group 3 includes two aspherical plastic lenses, and lens group 4 includes two aspherical plastic lenses. Specifically, lens 1-1, lens 1-2, lens 1-3, lens 1-4, lens 1-5, lens 2-1, lens 3-2 and lens 4-2 are glass spherical lenses. Lens 2-2, lens 2-3, lens 3-1, lens 3-3, lens 4-1 and lens 4-3 are aspherical plastic lenses. The detailed parameters of each lens in the embodiment shown in Figure 3 are shown in Table 4 below.

[0067] Table 4

[0068] The aspheric coefficients of the aspheric plastic lenses in the embodiment shown in FIG. 3 are shown in Table 5 below.

[0069] Table 5

[0070] The following describes the zooming scenarios of the optical lens in the embodiments of the present application. For example, as lens group 2 and lens group 4 move, the focal length of the optical lens can vary from 5.5mm to 129mm. That is, the focal length of the optical lens provided in the embodiments of the present application reaches 5.5mm at the wide-angle end and 129mm at the telephoto end.

[0071] FIG4 is a schematic diagram of a zoom mode of the optical lens in an embodiment of the present application. As shown in FIG4 , as the positions of lens group 2 and lens group 4 move, the focal length of the optical lens can change. Based on the change in the focal length of the optical lens, this embodiment can divide the optical lens into three states: short focus, medium focus, and long focus. Taking the initial state of the optical lens as an example of short focus, lens group 2 moves in the direction close to lens group 3, and lens group 4 moves in the direction close to lens group 3, so that the optical lens switches to the medium focus state. Then, lens group 2 continues to move in the direction close to lens group 3, and lens group 4 moves in the direction away from lens group 3, so that the optical lens switches to the long focus state.

[0072] In the scenario shown in FIG2 , as lens group 2 and lens group 4 move, the focal length change parameters of the optical lens can be shown in the following Table 6. In Table 6, Spacing 1 represents the distance between lens group 1 and lens group 2, Spacing 2 represents the distance between lens group 2 and lens group 3, Spacing 3 represents the distance between lens group 3 and lens group 4, and Spacing 4 represents the distance between lens group 4 and the protective glass.

[0073] Table 6

[0074] In the scenario shown in FIG3 , as lens group 2 and lens group 4 move, the focal length change parameters of the optical lens can be shown in Table 7 below. In Table 7, Spacing 1 represents the distance between lens group 1 and lens group 2, Spacing 2 represents the distance between lens group 2 and lens group 3, Spacing 3 represents the distance between lens group 3 and lens group 4, and Spacing 4 represents the distance between lens group 4 and the protective glass.

[0075] Table 7

[0076] From the above introduction, it can be seen that in the embodiment of the present application, the optical lens includes four lens groups. The number of lens groups used is relatively small while ensuring the realization of the optical lens function, which facilitates miniaturization. At least one lens group in the optical lens includes an even number of aspherical plastic lenses. On the one hand, the use of some aspherical plastic lenses can reduce costs while ensuring good imaging quality; on the other hand, designing an even number of aspherical plastic lenses in the same lens group helps to improve the thermal stability of the optical lens, that is, reduces the impact of ambient temperature on imaging quality, and can ensure good imaging in an environment of -30°C to 70°C.

[0077] The present application also provides a camera and an electronic device, which are described below. It should be understood that the electronic device can be a mobile phone, tablet computer, wearable device, dome camera, or other device with a shooting function, and the specific details are not limited here.

[0078] FIG5 is a schematic diagram of the structure of a camera in an embodiment of the present application. As shown in FIG5 , the camera includes an optical lens 101 and a photosensitive element 102. The photosensitive element 102 is located on the image side of the optical lens 101. The optical lens 101 is used to project a light beam from the object to be photographed onto the photosensitive element 102, and the photosensitive element 102 is used to convert the light beam into image data. In some possible implementations, the camera further includes a prism or a reflector for changing the direction of the light path so that the light after passing through the prism or reflector can propagate along the extension direction of the optical axis of the optical lens 101. For example, this forms a light path deflection to realize a periscope light path.

[0079] It should be understood that the optical lens 101 can be any of the optical lenses described in the above embodiments and will not be further described here. The photosensitive element 102 is a semiconductor chip with hundreds of thousands to millions of photodiodes on its surface. When exposed to light, these photodiodes generate an electric charge. The photosensitive element 102 can be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). A CCD is made of a highly sensitive semiconductor material and can convert light into an electric charge. A CCD consists of many photosensitive units, typically measured in megapixels. When light strikes the surface of a CCD, each photosensitive unit reflects an electric charge on the component. The signals generated by all the photosensitive units are added together to form a complete image. CMOS devices primarily utilize semiconductors made of silicon and germanium, resulting in the coexistence of semiconductors with N (negative charge) and P (positive charge) levels on the CMOS device. The current generated by these two complementary effects can be recorded and interpreted by the image sensor as an image.

[0080] FIG6 is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. As shown in FIG6 , the electronic device includes a camera 201 and an image processor 202. The camera 201 may be the camera described in FIG5 . The image processor 202 is connected to the camera 201 and is configured to acquire image data from the camera 201 and process the image data.

[0081] It should be noted that the communication connection between the camera 201 and the image processor 202 may include data transmission through electrical connection methods such as wiring, or data transmission may be achieved through coupling and other methods. It should be understood that the camera 201 and the image processor 202 may also achieve communication connection through other methods that can achieve data transmission. The function of the image processor 202 is to optimize the digital image signal through a series of complex mathematical algorithms, and finally transmit the processed signal to the display for display. The image processor 202 can be an image processing chip or a digital signal processing chip (DSP), etc., which can process image signals and digital signals. Its function is to transmit the data obtained by the photosensitive chip of the camera 201 to the central processing unit in a timely and rapid manner and refresh the photosensitive chip. Therefore, the quality and stability of the DSP chip directly affect the picture quality (such as color saturation, clarity, etc.).

[0082] In some possible implementations, the electronic device may further include an analog-to-digital converter (ADC). The ADC is connected between the camera 201 and the image processor 202. The ADC is used to convert the signal generated by the camera 201 into a digital image signal and transmit it to the image processor 202. The image processor 202 then processes the digital image signal and ultimately displays the image or video on the display.

[0083] In some possible implementations, the electronic device may further include a memory that is communicatively connected to the image processor 202. The image processor 202 processes the digital image signal and then transfers the image to the memory, allowing the image to be retrieved from the memory and displayed on the display at any time when the image is needed. In some embodiments, the image processor 202 may also compress the processed digital image signal before storing it in the memory to conserve memory space.

[0084] As described above, the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of this application. In the absence of conflict, the embodiments of this application and the features therein can be combined with each other.

Claims

1. An optical lens, characterized in that, Comprising: A first lens group, a second lens group, a third lens group, and a fourth lens group arranged along the optical axis from the object side to the image side, wherein the positions of the first lens group and the third lens group are fixed, and the second lens group and the fourth lens group can move along the optical axis; The first lens group, the third lens group, and the fourth lens group have positive optical powers, the second lens group has a negative optical power, and at least one lens group in the optical lens includes an even number of aspherical plastic lenses.

2. The optical lens according to claim 1, wherein Every two aspherical plastic lenses in the same lens group form a pair. The signs of the optical powers of the two aspherical plastic lenses in the same pair are opposite, and the ratio of the absolute values of the optical powers of the two aspherical plastic lenses in the same pair satisfies wherein, represents the optical power of the first aspherical plastic lens among the two aspherical plastic lenses in the same pair, represents the optical power of the second aspherical plastic lens among the two aspherical plastic lenses in the same pair.

3. The optical lens according to claim 1 or 2, characterized in that, Each lens group in the optical lens includes at least one glass lens.

4. The optical lens according to claim 3, characterized in that Each glass lens in the optical lens is a spherical glass lens.

5. The optical lens according to any one of claims 1 to 4, characterized in that, The optical lens further includes a fixed-position aperture stop located between the second lens group and the third lens group, and the diameter of the aperture stop can be adjusted.

6. The optical lens according to claim 5, wherein The minimum distance between the aperture stop and the second lens group is greater than or equal to 0.5 mm, and the distance between the aperture stop and the third lens group is greater than or equal to 0.5 mm.

7. The optical lens according to any one of claims 1 to 6, characterized in that, The optical lens satisfies the following relational expressions: -0.5 < f2 / f1 < 0, 0 < f3 / f1 < 1, 0.5 < f4 / f1 < 1; wherein, f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, f3 represents the focal length of the third lens group, and f4 represents the focal length of the fourth lens group.

8. The optical lens according to any one of claims 1 to 7, characterized in that, The first lens group includes two aspherical plastic lenses, the second lens group includes two aspherical plastic lenses, and the third lens group includes two aspherical plastic lenses.

9. The optical lens according to claim 8, wherein, The first lens group includes lens 1-1, lens 1-2, lens 1-3, lens 1-4, and lens 1-5, the second lens group includes lens 2-1, lens 2-2, and lens 2-3, the third lens group includes lens 3-1, lens 3-2, and lens 3-3, and the fourth lens group includes lens 4-1, lens 4-2, and lens 4-3; Lens 1-1, lens 1-2, lens 1-4, lens 2-1, lens 3-2, lens 4-1, lens 4-2, and lens 4-3 are spherical glass lenses, and lens 1-3, lens 1-5, lens 2-2, lens 2-3, lens 3-1, and lens 3-3 are aspherical plastic lenses.

10. The optical lens according to any one of claims 1 to 7, characterized in that, The second lens group includes two aspherical plastic lenses, the third lens group includes two aspherical plastic lenses, and the fourth lens group includes two aspherical plastic lenses.

11. The optical lens according to claim 10, wherein The first lens group includes lens 1-1, lens 1-2, lens 1-3, lens 1-4, and lens 1-5, the second lens group includes lens 2-1, lens 2-2, and lens 2-3, the third lens group includes lens 3-1, lens 3-2, and lens 3-3, and the fourth lens group includes lens 4-1, lens 4-2, and lens 4-3; Lens 1-1, lens 1-2, lens 1-3, lens 1-4, lens 1-5, lens 2-1, lens 3-2, and lens 4-2 are spherical glass lenses, and lens 2-2, lens 2-3, lens 3-1, lens 3-3, lens 4-1, and lens 4-3 are aspherical plastic lenses.

12. The optical lens according to any one of claims 1 to 11, characterized in that The second lens group is used for zooming by moving along the optical axis, and the fourth lens group is used for compensating for the shift of the image plane position by moving along the optical axis.

13. The optical lens according to any one of claims 1 to 12, characterized in that, As the positions of the second lens group and the fourth lens group move, the focal length of the optical lens varies in the range of 5.5 mm to 129 mm.

14. The optical lens according to any one of claims 1 to 13, characterized in that, In the optical lens, the first lens group has the largest aperture.

15. The optical lens according to any one of claims 1 to 14, characterized in that, The optical lens further includes a protective glass, and the protective glass is located on the image side of the fourth lens group.

16. The optical lens according to any one of claims 1 to 15, characterized in that, The aperture number of the optical lens varies in the range of 1.6 to 4.

8.

17. A camera, characterized in that, Comprising: An image sensor and the optical lens according to any one of claims 1 to 16, the image sensor being located on the image side of the optical lens, the optical lens being configured to project a light beam from a subject onto the image sensor, and the image sensor being configured to convert the light beam into image data.

18. An electronic device, characterized in that, Comprising: An image processor and the camera according to claim 17, the image processor being connected to the camera, the image processor being configured to obtain image data from the camera and process the image data.

Images