Optical lens, camera module and electronic equipment

Abstract

The invention provides an optical lens, a camera module and electronic equipment, the optical lens comprises a first lens group, a first prism and a second lens group which are sequentially arranged from an object side to an image side, and the first lens group has positive focal power; the first prism is used for reflecting the light from the first lens group at least twice; the second lens group comprises a first lens and a second lens which are sequentially arranged in the optical axis direction, the first lens is provided with a first free-appearance curved surface, the second lens is provided with a second free-appearance curved surface, and the first lens and the second lens can generate relative displacement in the direction perpendicular to the optical axis of the second lens group so as to achieve optical focusing. The first prism and the second lens group can be arranged more tightly along the direction of the optical axis, so that the size of the optical lens is reduced, the space required by movement of the first lens and the second lens can be compensated by empty areas existing at the peripheries of the first lens and the second lens in the direction perpendicular to the optical axis, and the overall size of the optical lens can be reduced. And miniaturization, lightening and thinning of the electronic equipment can be realized.

Description

TECHNICAL FIELD

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

[0002] With the continuous development of portable electronic devices such as mobile phones, users have increasingly high requirements for the shooting performance of the camera modules of electronic devices. Not only is it required that the camera modules configured by electronic devices can realize functions such as background blurring and clear night shooting, but it is also required that the camera modules configured by electronic devices can realize long-focus shooting and macro shooting.

[0003] In related technologies, the optical lens in the camera module realizes optical focusing by moving the movable lens group inside the optical lens on the optical axis in the front and back directions, so that the camera module can shoot clear pictures in long-focus shooting and macro shooting scenes. However, the focusing stroke required for optical lens focusing is large, which makes the volume of the camera module also large, which is not conducive to the miniaturization and thinning of electronic devices. SUMMARY

[0004] Embodiments of the present application provide an optical lens, a camera module and an electronic device. By improving the structure of the optical lens and changing the moving direction of the lens in the movable lens group during focusing, the problem of large size of the camera module in the prior art is solved.

[0005] In a first aspect, an optical lens is provided, comprising a first lens group, a first prism and a second lens group arranged in sequence from an object side to an image side;

[0006] The first lens group has positive refractive power;

[0007] The first prism is configured to reflect light from the first lens group at least twice;

[0008] The second lens group is configured to receive light emitted from the first prism, and comprises a first lens and a second lens arranged in sequence along the optical axis of the second lens group. The first lens has a first free-form surface, the second lens has a second free-form surface, and the first lens and the second lens can be relatively displaced in a direction perpendicular to the optical axis of the second lens group to realize optical focusing of the optical lens.

[0009] It should be noted that the optical axis of the second lens group herein refers to the axis line perpendicular to each lens of the second lens group, and the optical axis of the second lens group is part of the optical axis of the optical lens.

[0010] It should be noted that the first lens group has positive refractive power, and the first lens group has a converging effect on light. A group of light emitted from the first lens group gradually converges during propagation, and eventually the group of light may intersect at a point.

[0011] It should be noted that the free-form surface can have no symmetry axis, or can be symmetrical about a certain direction, or can be symmetrical about two directions, and the surface type of the free-form surface can be defined by a formula.

[0012] It should be noted that the first lens and the second lens can be relatively displaced in the direction perpendicular to the optical axis, and the focal length of the first lens and the second lens can be changed in a manner of changing the position by simultaneously moving the first lens and the second lens to achieve the focusing of the optical lens. For example, the first lens and the second lens can move towards opposite directions, and at this time, the moving distance of the first lens and the second lens can be equal or not equal, such as the first lens moves 2 mm and the second lens moves 2 mm or 2.5 mm; for another example, the first lens and the second lens can move towards the same direction, but the moving distance of the first lens and the second lens is different, thereby generating a relative displacement, such as the first lens moves 2 mm and the second lens moves 3 mm, at this time, a displacement of 1 mm is generated between the first lens and the second lens; for another example, the first lens and the second lens can also move towards two directions arranged at an included angle respectively, that is, the first lens and the second lens move towards different directions and the moving directions of the first lens and the second lens are not parallel, thereby generating a relative displacement.

[0013] In other examples, the optical focusing of the optical lens can also be achieved by moving the first lens or the second lens alone, for example, the first lens can be moved alone so that the focal length of the first lens is changed in a manner of changing the position, and the second lens can be fixed, at this time, the second lens can be a liquid lens, a liquid crystal lens or the like, and the focal length of the second lens can be adjusted by changing the surface type of the second free-form surface thereof. The liquid lens is a kind of optical element without mechanical connection made of one or more liquids, and the internal parameters of the optical element can be changed by external control, simply speaking, the medium of the lens is changed from glass to liquid, and more accurately, the liquid lens is a kind of new optical element which dynamically adjusts the refractive index of the lens or changes the focal length by changing the surface shape; the liquid crystal lens is a kind of optical element which changes the arrangement of liquid crystal molecules by changing the voltage applied on the liquid crystal material, so as to change the refractive index distribution of the lens and achieve the adjustment of optical power.

[0014] It should be noted that the focal length of the first lens and the second lens located in the part of the optical axis can be changed to achieve the focusing of the optical lens, and both belong to the zoom lens.

[0015] The first free-form surface is arranged on the first lens, and the second free-form surface is arranged on the second lens. The shapes of the first lens and the second lens are changed so that the first lens and the second lens can be relatively displaced in the direction perpendicular to the optical axis to achieve focusing. Compared with the traditional design of moving focusing in the direction of the optical axis, the focusing stroke required in the direction perpendicular to the optical axis is smaller, and in the direction perpendicular to the optical axis, the size of the first prism usually constitutes the size bottleneck of the optical lens, that is, the size of the first prism is usually larger than the size of the lens in the direction perpendicular to the optical axis. Therefore, the smaller focusing stroke of the first lens and the second lens does not additionally or excessively occupy the space in the direction perpendicular to the optical axis, so that the size of the camera module can be saved. The first lens and the second lens do not produce displacement in the direction of the optical axis, so that the first lens and the second lens can be arranged more closely. Therefore, the total optical length of the optical lens can be reduced, the volume of the camera module is further reduced, and the miniaturization and thin design of the electronic device are facilitated.

[0016] Since the first prism can reflect the light from the first lens group at least twice, the propagation distance of the light in the first prism is extended, and the first lens group with positive focal power converges the light. Therefore, the light emitted from the first prism has a higher convergence degree, and the required light aperture of the light passing through the second lens group is smaller. Therefore, the size of the first lens and the second lens can be reduced, and the focusing stroke of the first lens and the second lens can be correspondingly reduced. The space required for the movement of the first lens and the second lens can be compensated by the space generated at the periphery of the first lens and the second lens due to the size reduction. Therefore, the space reserved for focusing in the optical lens can be reduced or not required. Therefore, the focusing stroke of the first lens and the second lens in the direction perpendicular to the optical axis can be further reduced, the size of the camera module can be saved, and the miniaturization and thin design of the electronic device are facilitated.

[0017] Through the above arrangement, the at least twice reflection of the light by the first prism can reduce the required light aperture of the light passing through the second lens group, thereby reducing the size of the first lens and the second lens and the focusing stroke of the two. The smaller focusing stroke of the first lens and the second lens does not additionally or excessively occupy the space in the direction perpendicular to the optical axis, and the arrangement of the first prism and the second lens group in the direction of the optical axis can be more closely arranged. Therefore, the size of the camera module can be saved in the direction of the optical axis and the direction perpendicular to the optical axis, the volume of the camera module can be reduced, and the miniaturization and thin design of the electronic device are facilitated.

[0018] In the example, the first lens and the second lens can be moved in a direction perpendicular to the optical axis, and in an example, a mechanical member such as a focusing motor can be arranged in the camera module and connected to the controller of the electronic device, and the first lens and the second lens are driven to move by the mechanical member to realize automatic focusing of the optical lens.

[0019] In some examples, the moving direction and distance of the first lens and the second lens can be designed by using a pre-calibration method, for example, before the electronic device is shipped, the distance information of the first lens and the second lens to be moved at different object distances is obtained by testing, and the related information parameters are recorded in the memory of the corresponding electronic device. When the electronic device is used to take a photo, the actual object distance information can be measured and obtained by the camera module of the electronic device, and then the actual object distance information is fed back to the controller of the electronic device. The position moving information of the first lens and the second lens is fed back to the corresponding mechanical member by the cooperation of the controller and the memory, and the corresponding mechanical member is driven to move the first lens and the second lens, so as to realize the automatic focusing of the optical lens.

[0020] In a possible implementation, the moving direction of the first lens and the second lens is perpendicular to the light-in direction of the optical lens.

[0021] In a possible implementation, the first free-form surface and the second free-form surface are both Alvarez free-form surfaces.

[0022] In order to accurately define the parameters of the Alvarez free-form surface, a rectangular coordinate system with X-axis, Y-axis and Z-axis perpendicular to each other can be used, wherein the direction of the Z-axis is the optical axis direction, the direction of the X-axis is the moving direction of the lens, and the direction of the Y-axis is perpendicular to the directions of the Z-axis and the X-axis. The surface type of the Alvarez free-form surface can be described by formula (1):

[0023]

[0024] In order to ensure that the thinnest part of the lens element has sufficient mechanical strength without changing the optical properties of the lens, a constant can be added to formula (1) to obtain the thickness expression of the two Alvarez lenses:

[0025]

[0026] Wherein, A and C are constants, and C can ensure that the thinnest part of the lens element has sufficient mechanical strength; when the two Alvarez lenses are combined and no relative displacement occurs between them, the combined thickness of the two Alvarez lenses T = T1 + T2 = 2C, in this case, the combined effect of the two Alvarez lenses is equivalent to a parallel plate, which has no deflection ability for light.

[0027] When two Alvarez lenses are moved in opposite directions by the same distance e, formula (2) and formula (3) can be changed to:

[0028]

[0029]

[0030] The thickness of the combination of two Alvarez lenses is:

[0031]

[0032] Where -2Ae(y 2 +x 2 ) can be expressed as a spherical surface with a positive focal power proportional to Ae, and the rest of the terms in formula (6) are independent of the values of xy, so it can be concluded that the combination of two Alvarez lenses can form a spherical mirror.

[0033] From formula (6), it can be seen that the value of A determines the range of change of the focal power when e is displaced, and the focal length of the spherical mirror equivalent to the combination of two Alvarez lenses is:

[0034]

[0035] Where n is the refractive index of the lens material.

[0036] From formula (7), it can be seen that the focal length of the spherical mirror equivalent to the combination of two Alvarez lenses can change with the displacement of the two Alvarez lenses, so the first lens and the second lens can adjust the combined focal length during the movement in the direction perpendicular to the optical axis, and realize focusing on different object distances.

[0037] From formula (7), it can be seen that the focal length of the spherical mirror equivalent to the combination of two Alvarez lenses can change with the displacement of the two Alvarez lenses, so in this example, the first lens and the second lens can adjust the combined focal length during the movement in the direction perpendicular to the optical axis, and realize focusing on different object distances.

[0038] It should be noted that the moving direction of the Alvarez lens is related to its surface type, and the Alvarez lens defined in formula (1) needs to be moved in the X-axis direction in the formula, if you want to change the moving direction of the Alvarez lens, for example, set the moving direction of the Alvarez lens to move in the Y-axis direction, then formula (1) can be adjusted to:

[0039]

[0040] Therefore, the first free-form surface and the second free-form surface are set as Alvarez free-form surfaces, and the surface formula of the Alvarez free-form surfaces can be determined according to the moving direction of the Alvarez free-form surfaces, so that the design difficulty of the optical lens is reduced.

[0041] In an example, the first free-form surface and the second free-form surface can also be free-form surfaces other than the Alvarez free-form surfaces, that is, the first lens and the second lens can also be lenses other than the Alvarez lenses, for example, the first lens and the second lens can also be Lohmann lenses; of course, the first free-form surface on the first lens and the second free-form surface on the second lens can also be defined by other surface formulas.

[0042] In a possible implementation, one of the first lens and the second lens has positive focal power, and the other has negative focal power, and the moving directions of the first lens and the second lens are opposite.

[0043] For example, the first lens can be set to have positive focal power so that the first lens can converge light rays, and the second lens can be set to have negative focal power so that the second lens can diverge light rays, or the first lens can be set to have negative focal power and the second lens can be set to have positive focal power. The first lens and the second lens are set to move in opposite directions, and the optical axis position of the second lens group does not change during the movement of the first lens and the second lens, so that the center of the group of light rays entering the second lens group can coincide with the optical axis of the second lens group; the first lens and the second lens can cause the propagation direction of the light rays to be deflected during the processing of the light rays, the first lens (or the second lens) having positive focal power can converge the light rays, and the second lens (or the first lens) having negative focal power can diverge the light rays, the opposite processing of the light rays by the first lens and the second lens can cause the deflection directions of the light rays by the first lens and the second lens to be opposite, so that the adjustment of the deflection direction of the light rays by the first lens and the second lens can be complementary, the deviation between the light rays and the optical axis can be reduced, the off-axis aberration of the final imaging can be reduced, and the imaging quality of the camera module can be improved.

[0044] In some examples, the first free-form surface is located on a side of the first lens close to the second lens, and the second free-form surface is located on a side of the second lens close to the first lens, so that the relative distance between the first free-form surface and the second free-form surface can be shortened. It can be understood that the deviation of the light from the optical axis direction caused by the first lens will gradually increase after the light exits the first lens and before the light enters the second lens. Shortening the relative distance between the first free-form surface and the second free-form surface can shorten the distance of the light between the first free-form surface and the second free-form surface. In this way, the deviation of the light from the optical axis direction after the light exits the first lens and before the light enters the second lens can be reduced, the correction difficulty of the second lens to the aberration of the first lens can be reduced, the off-axis aberration of the final imaging can be reduced, and thus the imaging quality of the camera module can be improved.

[0045] Of course, in some examples, the first free-form surface can be arranged on a side of the first lens away from the second lens, and the second free-form surface can be arranged on a side of the second lens away from the first lens.

[0046] The first lens also has a first surface opposite to the first free-form surface, and the first surface can be a plane, a spherical surface, an aspherical surface, or a free-form surface. Correspondingly, the second lens also has a second surface opposite to the second free-form surface, and the second surface can be a plane, a spherical surface, an aspherical surface, or a free-form surface.

[0047] In a possible implementation, the second lens group further includes a third lens having a third free-form surface. The third lens is arranged in the second lens group and can process the light. The third lens is close to the first lens and the second lens, which can reduce the correction difficulty of the aberration and improve the imaging quality of the camera module. The arrangement of the third lens can increase the number of lenses in the second lens group, so that the processing of the light is supplemented in the manner of increasing the number of lenses. In this way, the processing pressure of the first lens and the second lens on the light can be reduced, the sensitivity of the lenses is further reduced, and the stability of the optical lens is improved.

[0048] In an example, the third lens can be a lens with positive focal power or a lens with negative focal power.

[0049] In an example, the third free-form surface can also be an Alvarez free-form surface.

[0050] In an example, the third lens is fixedly arranged, that is, the third lens will not move during focusing.

[0051] The defocus MTF curves of the optical lens in this example at a spatial frequency of 100 lp / mm at an infinite object distance are concentrated between 0.4 and 0.8, which indicates that the optical lens can realize high-quality imaging at an infinite object distance when the third lens remains fixed, that is, the optical lens can realize high-quality imaging in the long-focus shooting mode.

[0052] In a possible implementation, the third lens is movable in a direction perpendicular to the optical axis of the second lens group.

[0053] The defocus MTF curves of the optical lens in this example at a spatial frequency of 100 lp / mm at an infinite object distance are concentrated between 0.4 and 0.8, which indicates that the optical lens can realize high-quality imaging at an infinite object distance when the third lens remains fixed, that is, the optical lens can realize high-quality imaging in the long-focus shooting mode.

[0054] In some examples, the moving direction and distance of the first lens, the second lens and the third lens can be designed by using a pre-calibration method, for example, before the electronic device is shipped, the distance that the first lens, the second lens and the third lens need to move at different object distances is obtained through testing, and the related parameters are recorded in the memory of the corresponding electronic device. When the electronic device is used to take a photo, the object distance information can be measured by the camera module of the electronic device, and then fed back to the controller of the electronic device. The position moving information of the first lens, the second lens and the third lens is fed back to the corresponding mechanical mover by the controller and the memory, and the corresponding mechanical mover is used to drive the first lens, the second lens and the third lens to move, so as to realize automatic focusing of the camera module.

[0055] In some examples, the moving direction of the third lens can be parallel to the moving direction of the first lens, and in other examples, the moving direction of the third lens can be non-parallel to the moving direction of the first lens, that is, the moving direction of the third lens is arranged at an angle with the moving direction of the first lens.

[0056] In a possible implementation, the moving direction of the third lens is perpendicular to the light-in direction of the optical lens, and the third free-form surface is symmetrical about a first symmetry axis, and the straight line direction of the first symmetry axis is arranged at an angle with the moving direction of the third lens.

[0057] In an example, the straight line direction of the first symmetry axis can be perpendicular to the moving direction of the third lens.

[0058] In a possible implementation, the third lens is located on a side of the first lens away from the second lens; or,

[0059] The third lens is located between the first lens and the second lens; or,

[0060] The third lens is located on a side of the second lens away from the first lens.

[0061] In some examples, the third lens is located on a side of the first lens away from the second lens, and in this case, the light passes through the third lens, the first lens and the second lens in sequence, or the third lens is located on a side of the second lens away from the first lens, and in this case, the light passes through the first lens, the second lens and the third lens in sequence. By arranging the third lens on a side of the first lens and the second lens used in pairs, the distance between the first lens and the second lens can be shortened, and thus the focusing effect of the optical lens can be improved, and the imaging quality of the camera module can be improved. In this example, the third free-form surface of the third lens can face the first lens or be away from the first lens.

[0062] In some examples, the third lens is located between the first lens and the second lens, and in this case, the light passes through the first lens, the third lens and the second lens in sequence, and thus the distance between the third lens and the first lens and the second lens is small, and in this case, the third lens can better correct the aberration generated by the first lens and the second lens; in this example, the third free-form surface of the third lens can face the first lens or the second lens.

[0063] In some examples, the third lens further has a third surface opposite to the third free-form surface, and the third surface can be a plane, a spherical surface, an aspherical surface or a free-form surface.

[0064] In one possible implementation, the combined focal length of the first lens and the second lens is F1, and the focal length of the second lens group is F2, where |F1| > 2|F2|.

[0065] It should be noted that the combined focal length of the first lens and the second lens can be understood as the equivalent focal length exhibited when the first lens and the second lens are used together. The refraction effect of light after passing through the first lens and the second lens can be equivalent to a single lens with a specific focal length. The focal length of this equivalent lens is the combined focal length of the first lens and the second lens.

[0066] The focal length of the second lens group is the combined focal length of all lenses within it. In this example, the second lens group includes a first lens, a second lens, and a third lens. Therefore, the focal length of the second lens group is equivalent to the combined focal length of the first, second, and third lenses. The combined focal length F1 of the first and second lenses can be positive, in which case the focal length of the third lens can be negative. Conversely, the combined focal length F1 of the first and second lenses can also be negative, in which case the focal length of the third lens can be positive. It is understandable that for lenses with negative optical power, the larger the absolute value of their focal length, the weaker their ability to diverge light; for lenses with positive optical power, the larger the value of their focal length, the stronger their ability to converge light. The weaker the focusing ability, the greater the divergence / convergence of light by a lens. This means that the stronger the divergence / convergence of light by a lens, the greater the deflection of light after passing through it, and the greater the aberrations caused by the lens. In other words, the greater the impact of the lens on the final image quality. Therefore, setting the absolute value of the combined focal length of the first and second lenses to be greater than twice the absolute value of the focal length of the second lens group can control the divergence / convergence of light by the first and second lenses, thereby reducing the aberrations caused by them and minimizing the impact of a single lens on the final image effect. Furthermore, the aberrations generated by the first and second lenses can be corrected by the third lens, thus reducing the aberrations generated by the second lens group and improving the imaging effect of the camera module.

[0067] In some embodiments, the first lens group includes a sixth lens. The surface of the sixth lens can be spherical or aspherical, that is, the surface of the sixth lens can be spherical or aspherical with a rotation axis and central symmetry. The sixth lens can process the light entering the first lens group to reduce aberrations and improve the imaging quality of the camera module. Within the first lens group, a seventh lens, an eighth lens, and other lenses can also be provided. The surfaces of these lenses can be spherical or aspherical with a rotation axis and central symmetry. In this way, the first lens group has multiple lenses to process the light.

[0068] In one possible implementation, the first lens group includes a fourth lens having a fourth free-form surface. The fourth lens can converge light rays entering the optical lens, allowing the light rays entering the first prism to gradually approach the optical axis during propagation, thus reducing the aperture required for the light rays to pass through the second lens group. The fourth free-form surface on the fourth lens allows it to process the light rays to reduce aberrations and improve the imaging quality of the camera module.

[0069] In one example, the fourth lens also has a fourth surface opposite to the fourth freeform surface. This fourth surface can be a plane, a spherical surface, an aspherical surface, or a freeform surface. The fourth freeform surface of the fourth lens can be located on the object side or the image side of the fourth lens.

[0070] In one possible implementation, the fourth freeform surface is symmetrical about the second axis of symmetry, and the first lens group further includes a fifth lens, which has a fifth freeform surface. The fifth freeform surface is symmetrical about the third axis of symmetry, and the straight line direction of the second axis of symmetry and the straight line direction of the third axis of symmetry are set at an angle.

[0071] The fifth lens can converge the light entering the optical lens. In this way, the fifth lens and the fourth lens can be used together to appropriately reduce the optical power of the fourth lens, thereby weakening the fourth lens's ability to converge light and reducing the deflection of light in the direction of propagation when passing through the fourth lens, thus reducing the aberrations caused by the fourth lens. By setting the straight line containing the second axis of symmetry and the straight line containing the third axis of symmetry to form an angle, the fourth lens and the fifth lens can correct the aberrations of the optical lens from different directions, thereby improving the imaging quality of the camera module.

[0072] In some examples, the direction of the line containing the second axis of symmetry is perpendicular to the direction of the line containing the third axis of symmetry.

[0073] In some examples, the fifth lens also has a fifth surface opposite to the fifth freeform surface. The fifth surface can be a plane, a sphere, an aspherical surface, or a freeform surface. The fifth freeform surface of the fifth lens can be located on the object side of the fifth lens or on the image side of the fifth lens.

[0074] In one possible implementation, the second group of mirrors has negative optical power.

[0075] The first lens group has positive optical power, and the second lens group with negative optical power works in conjunction with the first lens group with positive optical power to balance the optical path, making the overall structure of the optical lens more compact and reducing the length and size of the optical lens; in addition, it can also improve the sharpness and contrast of the optical lens, making the image sharper and more delicate.

[0076] In one possible implementation, the focal length of the second lens group is F3, and in macro shooting mode, the focal length of the second lens group is F4, and the optical lenses satisfy the following relationship:

[0077] |F3|<|F4|.

[0078] In telephoto shooting mode, light from distant objects strikes in a nearly parallel manner, while in macro shooting mode, light from close objects strikes in a nearly divergent manner. Without changing the focal length of the optical lens, the different points of intersection of these two types of light result in different positions of the image plane. This necessitates adjusting the image sensor's position. However, to ensure the image sensor receives all the light processed by the optical lens, its size is typically large. If a movable image sensor is used, the camera module requires a larger space, which is detrimental to miniaturization and thinning of electronic devices. To fix the image plane position of the camera module, the focal length of the second lens group can be adjusted, ensuring the image plane position remains essentially unchanged at different object distances, thus reducing image sensor movement. In macro shooting mode, where light strikes in a nearly divergent manner, the divergence capability of the second lens group can be reduced. In telephoto shooting mode, where light strikes in a nearly parallel manner, the divergence capability of the second lens group can be improved. For objects with negative focal lengths... For the second lens group, the weaker its ability to diverge light, the larger its optical power (i.e., the smaller the absolute value of the optical power). Numerically, focal length and optical power are inversely related; the smaller the absolute value of the optical power, the larger the absolute value of the focal length. Therefore, the ability of the second lens group to diverge light can be adjusted by changing the focal length. In macro shooting mode, the absolute value of the focal length of the second lens group can be increased; in telephoto shooting mode, the absolute value of the focal length of the second lens group can be decreased. In other words, by setting the absolute value of the focal length of the second lens group to be smaller in telephoto shooting mode than in macro shooting mode, the second lens group can achieve a stronger light-diffusing ability in telephoto shooting mode than in macro shooting mode. This allows the optical lens to focus, ensuring that the position of light rays at different object distances on the imaging surface within the camera module remains essentially unchanged. Thus, even with reduced or no movement of the image sensor, light rays can still converge on the image sensor and form a clear image on it.

[0079] In one possible implementation, the focal length of the first lens group is F5, the focal length of the optical lens is F6, and the optical lens satisfies the following relationship:

[0080] 0.2≤F5 / F6≤5.

[0081] The focal length of the first lens group is the combined focal length of all lenses within it. Similarly, the focal length of the optical lens is the combined focal length of all lenses within it. In this example, the first lens group includes a fourth and a fifth lens, and the focal length of the first lens group is the combined focal length of the fourth and fifth lenses. The optical lens includes a first, second, third, fourth, and fifth lens, and the focal length of the optical lens is the combined focal length of the first, second, third, fourth, and fifth lenses. The optical lens needs to converge light so that it can form an image on the image sensor; therefore, the optical lens has positive optical power. Setting the ratio of the focal length of the first lens group to the focal length of the optical lens between 0.2 and 5 allows control over the focal length of the first lens group, thereby controlling its optical power, reducing aberrations caused by the first lens group, and ultimately improving the imaging effect of the camera module.

[0082] For example, the value of F6 can be 20 to 25.

[0083] In one possible implementation, the maximum effective optical area size of the second lens group is D, and the optical lenses satisfy the following relationship:

[0084] D / IMH≤1.

[0085] Lenses have an optically effective area and an optically ineffective area located around the periphery of the optically effective area. The optically effective area refers to the region of the lens that can achieve the expected optical performance. Within this region, the refraction, reflection, and transmission characteristics of light meet the design requirements, enabling clear imaging or specific optical functions such as focusing, collimation, and beam splitting. The quality and performance of this region play a crucial role in the imaging quality, resolution, and optical efficiency of the entire optical system. The optically ineffective area refers to the region of the lens that cannot effectively participate or will negatively affect the expected optical performance. This may include the edge portion of the lens. Surface defects, irregular shapes, and non-uniform refractive indices caused by manufacturing processes, installation errors, or other factors cause additional aberrations, scattering, or absorption when light passes through these areas, thereby reducing the performance of the optical system. In some designs, the optically ineffective area may be blocked by a light shield or other structure to avoid its adverse effects on the optical system. When two or more lenses are used in combination, the overlap of the optically effective areas between the lenses changes with the position of the lenses, thus changing the size of the overall optically effective area of ​​the lens group.

[0086] In this example, during focusing, the movement of the lens changes the overlapping portion of the first and second lenses, altering the size of the optically effective area of ​​the second lens group. By setting the maximum optically effective area size D of the second lens group to be smaller than the system image height IMH of the optical lens, the optically effective areas of the first and second lenses can be appropriately reduced, thereby reducing the size of the first and second lenses. This results in a larger empty area around the first and second lenses to compensate for the space required for their movement, allowing for further reduction or elimination of the space reserved for focusing within the optical lens. This reduces the overall size of the optical lens and consequently the size of the camera module, which is beneficial for miniaturizing and thinning electronic devices.

[0087] In one possible implementation, the optical lens further includes a second prism located on the image side of the second lens group, the second prism being used to reflect light from the second lens group.

[0088] The second prism can reflect light from the second group of mirrors, thereby changing the direction of light propagation. This allows the orientation of the image sensor to be adjusted. For example, the surface of the image sensor used to receive light (usually the surface with the largest area of ​​the image sensor) can be set parallel to the width and length of the electronic device. In other words, the surface of the image sensor used to receive light can be perpendicular to the thickness direction of the electronic device, reducing the space occupied by the image sensor in the thickness direction of the electronic device and helping to reduce the thickness of the electronic device.

[0089] In one possible implementation, the first prism includes a first side surface, a second side surface, and a third side surface, wherein the angle between the first side surface and the second side surface is less than 45°, and light rays from the first mirror group are incident from the first side surface, reflected sequentially by the second side surface and the first side surface, and exit from the third side surface.

[0090] The angle between the first side surface of the first prism 20 and the second side surface of the first prism is set to less than 45°, which helps to reduce the size of the optical lens in the thickness direction of the electronic device, thereby helping to reduce the size of the camera module in the thickness direction of the electronic device, which is beneficial to reducing the thickness of the electronic device.

[0091] The value of the included angle α between the first side and the second side is related to the refractive index of the first prism 20. In order to satisfy total internal reflection, the included angle α and the refractive index n1 of the first prism can satisfy the following relationship: n1≥1 / sin(2α).

[0092] In one possible implementation, the second prism includes a fourth side surface, a fifth side surface, and a sixth side surface, wherein the angle between the fifth side surface and the sixth side surface is less than 45°, and light rays from the second prism group are incident on the fourth side surface, reflected sequentially by the fifth side surface and the fourth side surface, and exit from the sixth side surface.

[0093] Setting the angle between the fifth and sixth sides of the second prism to less than 45° helps to reduce the size of the optical lens in the thickness direction of the electronic device, thereby helping to reduce the size of the camera module in the thickness direction of the electronic device, which is beneficial to reducing the thickness of the electronic device.

[0094] The value of the angle β between the fifth and sixth sides is related to the refractive index of the second prism. In order to satisfy total internal reflection, the angle β and the refractive index n2 of the second prism can satisfy the following relationship: n2≥1 / sin(2β).

[0095] In one example, the ranges for α and β can be: 22° < α = β < 28°.

[0096] Secondly, a camera module is provided, including an image sensor and the aforementioned optical lens, wherein the optical lens is used to image a scene on the object side onto the image sensor.

[0097] Because the optical lens in the above example has a small overall size, the camera module containing this optical lens is also small in size, taking up less space in the electronic device, which is beneficial for achieving miniaturization and thinning of the electronic device.

[0098] For example, a possible design of the camera module is as follows: The camera module includes an aperture stop, a first lens group, a first prism, a second lens group, a second prism, a filter, and an image sensor arranged sequentially from the object side to the image side. The first lens group includes a fourth lens and a fifth lens. The fourth freeform surface of the fourth lens and the fifth freeform surface of the fifth lens are arranged opposite to each other, and the fourth freeform surface is symmetrical about a second axis of symmetry, while the fifth freeform surface is symmetrical about a third axis of symmetry. The second and third axes of symmetry are perpendicular. The second lens group includes a first lens, a second lens, and a third lens. Each of the first, second, and third lenses can be... The first and second lenses move in opposite directions along a direction perpendicular to the optical axis. The first freeform surface of the first lens and the second freeform surface of the second lens are positioned opposite each other, and both the first and second freeform surfaces are Alvarez freeform surfaces. The third lens is located on the image side of the first lens, and the third freeform surface of the third lens is positioned towards the first lens. The third freeform surface is symmetrical about the first axis of symmetry. The angle α between the first and second sides of the first prism is equal to the angle β between the fifth and sixth sides of the second prism, and 22° < α = β < 28°.

[0099] Thirdly, an electronic device is provided, including an image processor and the aforementioned camera module, wherein the camera module is used to acquire image data and input the image data into the image processor, and the image processor is used to process the image data.

[0100] Since the camera module in any of the above examples is small in size and occupies little space in the electronic device, this example can reduce the size of the electronic device, achieving miniaturization and thinning.

[0101] When shooting with an electronic device, the first prism of the optical lens inside the electronic device can reflect light entering the camera module at least twice. This increases the convergence of the light emitted from the first prism and reduces the aperture required for the light to pass through the second lens group. This allows for a reduction in the size of the first and second lenses. The reduced size of the first and second lenses creates a periphery that compensates for the space required for their movement, thus reducing the extra space needed for focusing. Furthermore, the first prism's at least two reflections of light from the first lens group further reduce the aperture of the second lens group. Reducing the size of the lens also reduces the travel distance of the first and second lenses during focusing, i.e., reducing the focusing distance of the first and second lenses. This reduces or eliminates the need for additional space reserved for focusing within the optical lens. Since the first and second lenses do not shift in direction, the first prism and the second lens group can be arranged more closely along the optical axis to reduce the size of the optical lens. In the direction perpendicular to the optical axis, the empty areas around the first and second lenses can compensate for the space required for their movement. Therefore, the space reserved for focusing within the optical lens can be reduced or eliminated, which is beneficial for miniaturizing and thinning electronic devices. Attached Figure Description

[0102] Figure 1 This is a schematic diagram of the optical lens structure in related technologies. Figure 1 .

[0103] Figure 2 This is a schematic diagram of the optical lens structure in related technologies. Figure 2 .

[0104] Figure 3 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application.

[0105] Figure 4 This is a schematic diagram of the structure of the optical lens and image sensor provided in the embodiments of this application.

[0106] Figure 5 yesFigure 4 A schematic diagram of the second lens group in the optical lens shown.

[0107] Figure 6 This is a schematic diagram illustrating the principle of a zoom lens in an optical system.

[0108] Figure 7 yes Figure 4 The diagram shows the equivalent optical path of the optical lens at infinity in one embodiment.

[0109] Figure 8 yes Figure 4 The diagram shown illustrates the equivalent optical path of the optical lens at an object distance of 10 cm in one embodiment.

[0110] Figure 9 This is a schematic diagram of the optically effective area in the lens provided in this embodiment.

[0111] Figure 10 This is a schematic diagram of the principle of the Alvarez freeform surface provided in the embodiments of this application.

[0112] Figure 11 yes Figure 4 The diagram shows the modulation transfer function of the optical lens at infinity in one embodiment.

[0113] Figure 12 yes Figure 4 The diagram shows the modulation transfer function of the optical lens at an object distance of 10 cm in one embodiment.

[0114] Figure 13 yes Figure 4 The diagram shows an imaging distortion of an optical lens in one embodiment.

[0115] Figure 14 yes Figure 4 The diagram shows the equivalent optical path of the optical lens at infinity in another embodiment.

[0116] Figure 15 yes Figure 4 The diagram shows the equivalent optical path of the optical lens at an object distance of 10 cm in another embodiment.

[0117] Figure 16 yes Figure 4 The diagram shows the modulation transfer function of the optical lens at infinity in another embodiment.

[0118] Figure 17 yes Figure 4 The diagram shows the modulation transfer function of the optical lens at an object distance of 10 cm in another embodiment.

[0119] Figure 18 yes Figure 4The diagram shows an imaging distortion of the optical lens in another embodiment.

[0120] Figure 19 yes Figure 5 A schematic diagram of the A-direction viewing angle of the third lens in the second lens group shown.

[0121] Figure 20 yes Figure 4 A schematic diagram of the first lens group in the optical lens shown.

[0122] Figure 21 yes Figure 20 A schematic diagram of the B-direction viewing angle of the fourth and fifth lenses in the first lens group shown.

[0123] Figure label:

[0124] 1' Front prism; 2' Fixed lens group; 21' First lens; 3' Image sensor; 4' Rear prism; 5' Movable lens group; 51' Second lens;

[0125] 1000. Electronic devices;

[0126] 100. Housing; 1001. Frame; 1002. Back cover; 1003. Lens protection lens; 200. Display screen; 300. Camera module;

[0127] 1. Optical lens; 10. First lens group; 11. Fourth lens; S4. Fourth freeform surface; G4. Fourth surface; 12. Fifth lens; S5. Fifth freeform surface, G5. Fifth surface; 20. First prism; 21. First side surface; 22. Second side surface; 23. Third side surface; 30. Second lens group; 31. First lens; S1. First freeform surface; G1. First surface; 32. Second lens; S2. Second freeform surface; G2. Second surface; 33. Third lens; S3. Third freeform surface; G3. Third surface; 34. First axis of symmetry; 35. Second axis of symmetry; 36. Third axis of symmetry; P1. Optical effective area; P2. Optical ineffective area; 40. Second prism; 41. Fourth side surface; 42. Fifth side surface; 43. Sixth side surface; 50. Aperture stop; 60. Image sensor; 70. Filter. Detailed Implementation

[0128] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0129] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0130] In the description of this application, it should be understood that the terms "upper", "lower", "side", "front", "rear", etc., indicate the orientation or positional relationship based on the installation orientation or positional relationship, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0131] Hereinafter, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0132] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0133] For ease of understanding, the technical terms used in this application will be explained and described below.

[0134] Lens: A component that uses the refraction principle of a lens to allow light from a scene to pass through the lens and form a clear image on the focal plane.

[0135] Lens group: A combination of one or more lenses. The entire lens group can be moved, or at least one lens in the lens group can be moved. In this application, lens group can also be understood as a lens assembly or lens group.

[0136] Optical axis (OA): This is an axis perpendicular to the lens. The lens optical axis is the axis perpendicular to all the lenses within the lens. Depending on the arrangement of the lenses within the lens, the lens optical axis can be a straight line (i.e., the centers of all lenses lie on the same straight line), or it can be a broken line with one or more bends (i.e., at least some lenses are not collinear). When light rays parallel to the optical axis enter a convex lens, an ideal convex lens should converge all the light rays to a single point behind the lens; this point where all the light rays converge is the focal point.

[0137] Object side and image side: With the lens as the boundary, the side where the object is located is called the object side, and the surface of the lens closest to the object side can be called the object side surface; 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 closest to the image side can be called the image side surface.

[0138] 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 distance from the optical center of a lens or lens group to the focal point when a distant object is projected into a sharp image on the focal plane. It can also be understood as the perpendicular distance from the optical center of the lens or lens group to the focal plane. From a practical perspective, it can be understood as the distance from the center of the lens to the image plane. For fixed-focus lenses, the position of their optical center remains constant; for camera modules, changes in the lens's optical center result in changes in the lens's focal length.

[0139] Effective focal length (EFFL): The distance from the principal plane of an optical system to the corresponding focal point.

[0140] Equivalent focal length: The equivalent focal length is the focal length of an optical lens that corresponds to the same imaging angle on a 135 camera module, converted from the viewing angle of images on different sized image sensors. In other words, the 135 camera module serves as a standard, converting the focal length of non-135 camera modules to the equivalent focal length of a 135 camera module. Equivalent focal length = Effective focal length of the optical lens * Focal length factor (or focal length multiplier), where the focal length factor is the ratio of the diagonal length of the sensor in a non-135 camera module to the diagonal length of the image sensor in a 135 camera module. Therefore, equivalent focal length = Effective focal length of the optical lens * Diagonal length of the image sensor in a 135 camera module / Total image height. For example, if the effective focal length of the optical lens is 14.8mm, the full image height is 7.0mm, and the diagonal length of the image sensor in the 135 format camera module is 43.27mm, then the equivalent focal length of the optical lens is approximately 14.8 * 43.27 / 7.0 ≈ 91.5mm.

[0141] Focal power: equal to the difference between the image-side convergence and the object-side convergence; it characterizes the ability of an optical system to deflect light rays. Focal power is commonly represented by the letter […]. Indicates the optical power of the refracting spherical surface. Where n' is the image-side refractive index, n is the object-side refractive index, r is the radius of the sphere, f' is the image focal length, and f is the object focal length. Optical power is generally expressed as the reciprocal of the image-side focal length (approximately assuming the refractive index of air is 1). The above optical power equation is universal for any optical system (regardless of paraxiality).

[0142] Optical power characterizes the ability of an optical system to refract incident parallel light rays. The larger the value, the more the parallel light rays are refracted; At that time, bending is convergent; At that time, the bending is divergent. When this occurs, it corresponds to plane refraction. In this case, axially parallel rays remain axially parallel rays after refraction, and no bending phenomenon occurs.

[0143] Autofocus (AF): Autofocus utilizes the principle of light reflection from the subject. The reflected light passes through the lens and is imaged and received on the image sensor. The computer then processes the image to determine the subject's distance and automatically moves the lens accordingly to achieve focus. The purpose of autofocus is to ensure that objects at different distances are clearly imaged on the image sensor. The camera module typically uses a voice coil motor (VCM) or similar power mechanism to control the forward and backward movement of the optical lens along the optical axis, thereby adjusting the distance between the lens and the image sensor to achieve autofocus.

[0144] Distortion, also known as image distortion, refers to the degree of distortion in the image formed by an optical system relative to the object itself. Distortion occurs due to the spherical aberration of the aperture. The height of the intersection point between the principal ray from different fields of view and the Gaussian image plane is not equal to the ideal image height; this difference is the distortion. Therefore, distortion only changes the imaging position of an off-axis object point on the ideal plane, causing a distortion in the image shape, but it does not affect the image's sharpness.

[0145] Total track length (TTL): refers to the total length from the head of the lens barrel to the imaging plane, and is the main factor that determines the height of the camera.

[0146] Freeform surfaces: In optics, surfaces without a rotational axis of symmetry are generally referred to as freeform surfaces.

[0147] Aberrations: In an optical system, the paraxial region possesses the properties of an ideal optical system, where paraxial rays emitted from a point on an object intersect the image plane at a single point. However, in reality, light rays passing through different apertures of a lens rarely intersect perfectly at a single point; instead, they deviate from the position of the paraxial image point. These differences are collectively referred to as aberrations.

[0148] Image height (IMH): This refers to half the diagonal length of the effective pixel area on the image sensor.

[0149] Field of view (FOV): In optical instruments, the field of view is the angle between the two edges of the lens, representing the maximum range through which the image of the object can pass through the lens. The size of the FOV determines the field of view of the optical instrument; a larger FOV results in a wider field of view but a smaller optical magnification. A shorter focal length results in a wider horizontal field of view, and consequently, a smaller image. The horizontal field of view narrows as the focal length increases, while the object being photographed increases in size.

[0150] Aperture stop (STO): It is an aperture stop that limits the maximum tilt angle of the edge rays in the imaging rays of an on-axis point, that is, the aperture stop with the smallest incident aperture angle.

[0151] Aperture: Aperture refers to the effective diameter through which light passes by an optical element (such as a lens or aperture). For a lens, aperture usually refers to the diameter of the largest circular area through which light can pass. The size of the aperture directly affects the amount of light passing through the optical system. For example, in a camera lens, a larger aperture allows more light to enter the camera, resulting in brighter and clearer images in low-light conditions and reduced noise. However, a large aperture may also lead to a shallower depth of field, where only a smaller area of ​​objects can be clearly imaged. Similarly, in a telescope, a larger aperture collects more light, resulting in brighter and clearer observations of celestial objects and the ability to resolve more details.

[0152] With the continuous development of portable electronic devices such as mobile phones, users have increasingly higher requirements for the photography performance of the camera modules of electronic devices. They not only require the camera modules of electronic devices to achieve functions such as background blur and clear shooting at night, but also require the camera modules of electronic devices to achieve telephoto shooting and macro shooting.

[0153] Telephoto photography refers to bringing distant objects closer for shooting, while macro photography refers to shooting objects at a relatively close shooting distance with a large magnification. It is often used to shoot very small objects, such as flowers and insects.

[0154] Figure 1 Schematic diagram of optical lens and image sensor structure in related technologies Figure 1 ,Figure 2 Schematic diagram of optical lens and image sensor structure in related technologies Figure 2 ;reference Figure 1 and Figure 2 The optical lens shown in the figure can be applied to electronic devices. The following example illustrates the application of an optical lens and image sensor in a mobile phone: Figure 1 The X' axis shown represents the incident direction of the object-side light rays, which is also the thickness direction of the phone. The Y' axis shown in the figure represents the length direction of the phone. The optical lens includes a front prism 1', multiple mirror groups, and a rear prism 4' arranged sequentially from the object side to the image side. The front prism 1' reflects the light rays incident along the X' axis, causing them to deflect by 90° and propagate along the Y' axis. The multiple mirror groups sequentially perform optical processing on the light rays from the front prism. The rear prism 4' reflects the light rays from the mirror groups, causing them to deflect by 90° and propagate along the X' axis. Since the rear prism 4' reflects the light rays, causing their propagation direction to deflect again, the image sensor 3' and the rear prism can be arranged along the X' axis, thereby giving the image sensor 3' a larger imaging area and improving image quality.

[0155] In the above scheme, the optical lens also includes a focusing motor (not shown in the figure). Between the front prism 1' and the rear prism 4', there are two lens groups. One lens group is a fixed lens group 2', which has multiple first lenses 21' arranged along the optical axis. The other lens group is a movable lens group 5' for focusing, which has multiple second lenses 51' arranged along the optical axis. When focusing is required, the focusing motor drives the movable lens group 5' to move back and forth along the optical axis to achieve optical focusing of the optical lens, meeting the user's shooting needs in different scenarios.

[0156] However, in the above scheme, the focusing stroke of the movable lens group 5' is relatively large, and a large gap is required between the fixed lens group 2' and the movable lens group 5' to meet the space required for the movement of the movable lens group 5'. This results in the optical lens having a large size in the Y' axis direction, which also makes the camera module larger in size, which is not conducive to the miniaturization and thinning of electronic devices.

[0157] In view of this, embodiments of this application provide an optical lens, a camera module, and an electronic device, which improve the structure of the optical lens and change the moving direction of the lens in the movable lens group during focusing, in order to solve the problem of the large size of the camera module in the prior art.

[0158] This application first provides an electronic device, which may be, for example, a mobile phone, tablet computer, laptop computer, television, in-vehicle equipment, wearable device, personal digital assistant (PDA), point of sale (POS), camera, video surveillance equipment, or other electronic products with photography or video recording functions. A mobile phone may be, for example, a conventional candybar phone or a foldable phone, such as a small vertical folding phone, a left-right inward folding phone, or a left-right outward folding phone. Wearable devices may be, for example, smart bracelets, smartwatches, wireless headphones, augmented reality (AR) glasses, AR headsets, virtual reality (VR) glasses, or VR headsets. This application embodiment uses a mobile phone as an example for illustration.

[0159] Figure 3 This is a schematic diagram of the structure of the electronic device 1000 provided in this application embodiment. This application embodiment uses a mobile phone as an example for description of the electronic device 1000.

[0160] Reference Figure 3 The electronic device 1000 includes a housing 100, a display screen 200, an image processor (not shown), and a camera module 300. In some embodiments, the housing 100 includes a frame 1001 and a back cover 1002. The frame 1001 and the back cover 1002 can be integrally formed or assembled into an integral structure. The display screen 200 and the back cover 1002 are respectively mounted on both sides of the frame 1001, together enclosing the internal cavity of the device. The display screen 200 can be a liquid crystal display (LCD) screen, an organic light emitting diode (OLED) screen, etc., wherein the OLED screen can be a flexible display screen or a rigid display screen.

[0161] The display screen 200 can be used to display images and can also integrate touch functionality for human-computer interaction. The camera module 300 is housed within the overall cavity of the device. The camera module 300 is used to acquire optical information from outside the electronic device 1000 and form corresponding image signals. The image processor is communicatively connected to the camera module 300. The image processor acquires and processes the image signals from the camera module 300. The communication connection between the camera module 300 and the image processor can include data transmission via electrical connections such as wiring, or data transmission via coupling. It is understood that the camera module 300 and the image processor can also communicate via other methods capable of data transmission.

[0162] In practical applications, the electronic device 1000 may have one camera module 300, that is, only include the camera module 300, or it may have two, three, four, five or more camera modules 300, including the camera module 300. When there are multiple camera modules 300, these multiple camera modules 300 can be arranged on the side of the electronic device 1000 in a certain way. For example, one or more of them can be set on the front side where the display screen 200 is located, and used as a front-facing camera, while the remaining one or more camera modules 300 can be set on the rear cover 1002, and used as a rear-facing camera.

[0163] In some examples, electronic device 1000 may include one or more of the following: a front-facing camera (module), a rear-facing camera, a main camera lens, a secondary camera lens, a telephoto lens, an ultra-wide-angle lens, a macro lens, or a depth-of-field lens, and camera module 300 may be any of the aforementioned lenses.

[0164] In some examples, the back cover 1002 may have a camera hole through which the camera module 300 collects light. The camera module 300 can be used as a rear camera of the electronic device 1000. Exemplarily, the electronic device 1000 may also include a lens protective lens 1003 for protecting the lens module. The lens protective lens 1003 is disposed on the housing 100 and covers the lens module. When the lens protective lens 1003 is used to protect the front-facing lens module, it may cover only the front-facing lens module or cover the entire front of the electronic device 1000. When the lens protective lens 1003 covers the entire front of the electronic device 1000, it can simultaneously protect both the front-facing lens module and the display screen 200. The lens protective lens 1003 is essentially a cover glass (CG). When the lens protective lens 1003 is used to protect the rear lens module, it can cover the entire back of the electronic device 1000, or it can be placed only at the corresponding position of the rear lens module to protect it. The lens protective lens 1003 can be made of glass, sapphire, ceramic, etc., and this application embodiment does not impose any special limitations. In some embodiments, the lens protective lens 1003 is transparent, so that light from outside the electronic device 1000 can pass through the lens protective lens 1003 and enter the lens module.

[0165] In some examples, the electronic device 1000 may also include an analog-to-digital converter (also called an A / D converter, not shown in the figure). The analog-to-digital converter is connected between the camera module 300 and the image processor. The analog-to-digital converter is used to convert the analog image signal generated by the camera module 300 into a digital image signal and transmit it to the image processor. The image processor then processes the digital image signal to obtain a processed image signal, which can be displayed as an image or video on the display screen 200.

[0166] In some examples, the electronic device 1000 may also include a memory (not shown) communicatively connected to an image processor. The image processor transmits processed image signals to the memory so that the processed image signals can be retrieved from the memory and displayed on the display screen 200 whenever the image needs to be viewed later. In some embodiments, the image processor may also compress the processed image signals before storing them in the memory to save memory space.

[0167] It should be understood that Figure 3 The electronic device 1000 shown is not limited to the above-mentioned devices, but may also include other devices, such as batteries, flashlights, fingerprint recognition modules, earpieces, buttons, sensors, etc. This application embodiment only uses an electronic device 1000 with a lens module as an example for illustration, but the components installed on the electronic device 1000 are not limited to this.

[0168] Figure 4 This is a schematic diagram of the optical lens 1 and image sensor 60 provided in an embodiment of this application. The camera module 300 provided in this embodiment is disposed in the inner cavity of the device, as shown in the figure. Figure 4 The camera module 300 includes an optical lens 1 and an image sensor 60. The image sensor 60 can be positioned on the imaging surface of the camera module 300, specifically on the image side of the optical lens 1. Light rays processed by the optical lens 1 are then recognized by the image sensor 60. The camera module 300 may also include a circuit board (not shown), on which the image sensor 60 can be mounted. Exemplarily, the camera module 300 operates as follows: light reflected from the subject passes through the optical lens 1 to generate an optical image, which is projected onto the image sensor 60. The image sensor 60 converts the optical image into an electrical signal, i.e., an analog image signal, and transmits it to an analog-to-digital converter (ADC), which then converts it into a digital image signal for the image processor.

[0169] The image sensor 60 (also called a photosensitive element) is a semiconductor chip containing hundreds of thousands to millions of photodiodes on its surface, which generate electrical charges when illuminated. The image sensor 60 can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). A CCD is made of a highly sensitive semiconductor material that converts light into electrical charges. It consists of many photosensitive units, typically measured in megapixels. When the surface of the CCD (the photosensitive surface) is illuminated, each photosensitive unit reflects a charge onto the component. The signals generated by all the photosensitive units are added together to form a complete image. A CMOS primarily utilizes silicon and germanium, creating a semiconductor where N- and P-polar semiconductors coexist. The current generated by these complementary effects can be recorded and interpreted by the processing chip as an image.

[0170] In some examples, refer to Figure 4 The camera module 300 also includes a filter 70. The filter 70 can be located between the optical lens 1 and the image sensor 60 to filter out unwanted wavelengths of light, preventing the image sensor 60 from producing false colors or ripples, thereby improving its effective resolution and color reproduction. Exemplarily, the filter 70 can be an infrared filter, such as an infrared radiation-cut filter (IRCF). In this embodiment, the filter 70 is a separate component located between the optical lens 1 and the image sensor 60. In other embodiments, the filter 70 can be placed at any position before the image sensor 60, or the filter 70 can be omitted entirely, and filtering can be achieved by surface treatment or material treatment of at least one optical element of the optical lens 1. This application does not strictly limit the specific embodiments of the structure or component used to achieve filtering.

[0171] For example, filter 70 can be achieved by vapor-depositing an infrared (IR) material coating onto a sapphire substrate.

[0172] For example, filter 70 can be a white glass filter or a blue glass filter, etc.

[0173] In some embodiments, the optical lens 1 may further include an aperture stop 50, see reference 1. Figure 4The aperture stop 50 can also be located on the object side of the first lens group 10; in other embodiments, the aperture stop 50 can be located between the first lens group 10 and the first prism 20; in still other embodiments, the aperture stop 50 can also be located between the first prism 20 and the second lens group 30. It should be understood that the aperture stop 50 can be used to adjust the aperture, filter out stray light, and improve the imaging quality of the lens module.

[0174] The aperture stop 50 can be a spacer structure or a variable fan blade structure; alternatively, the aperture stop 50 can be achieved through a surface coating process, such as forming the aperture stop 50 by spraying a light-shielding material onto the lens. The position of the aperture stop 50 can be fixed or variable. For example, the position of the aperture stop 50 can be variable, allowing it to be adjusted according to focusing conditions to be positioned between different lenses.

[0175] The embodiments of this application mainly involve structural improvements to the optical lens 1. The structure of the optical lens 1 will be described in detail below with reference to the accompanying drawings.

[0176] Figure 5 yes Figure 4 A schematic diagram of the second lens group 30 in optical lens 1 is shown; refer to Figure 4 and Figure 5 The optical lens 1 provided in this application includes a first lens group 10, a first prism 20 and a second lens group 30 arranged sequentially from the object side to the image side. The first lens group 10 has positive optical power. The first prism 20 is used to reflect light from the first lens group 10 at least twice. The second lens group 30 is used to receive light emitted from the first prism 20. The second lens group 30 includes a first lens 31 and a second lens 32 arranged sequentially along the optical axis. The first lens 31 has a first free-form surface S1 and the second lens 32 has a second free-form surface S2. The first lens 31 and the second lens 32 can be relatively displaced in a direction perpendicular to the optical axis of the second lens group 30 to achieve optical focusing of the optical lens 1.

[0177] It should be noted that the optical axis of the second lens group 30 here refers to the axis perpendicular to each lens passing through the second lens group 30, and the optical axis of the second lens group 30 is part of the optical axis of the optical lens 1.

[0178] It should be noted that the first group of mirrors 10 has positive optical power and has a converging effect on light. A group of light rays emitted from the first group of mirrors gradually approach each other during propagation, and eventually, the group of light rays may intersect at a point.

[0179] It should be noted that a freeform surface can be without an axis of symmetry, or it can be symmetrical about a certain direction, or symmetrical about two directions. The shape of a freeform surface can be defined by a formula.

[0180] It should be noted that the first lens 31 and the second lens 32 can be relatively displaced in the direction perpendicular to the optical axis. They can move simultaneously to change their positions and thus alter their focal lengths, achieving focusing of the optical lens 1. For example, the first lens 31 and the second lens 32 can move in opposite directions. For instance, when the first lens 31 moves along the positive X-axis as shown in the diagram, the second lens 32 moves along the negative X-axis as shown in the diagram. In this case, the moving distances of the first lens 31 and the second lens 32 can be equal or unequal. For example, if the first lens 31 moves 2mm, the second lens 32 can move 2mm, or 2.5mm. Similarly, the first lens 31 and the second lens 32 can move... Lens 32 can move in the same direction, but the first lens 31 and the second lens 32 move different distances, thus producing relative displacement. For example, if the first lens 31 and the second lens 32 both move along the X-axis direction shown in the figure, the first lens 31 moves 2mm and the second lens 32 moves 3mm. At this time, a displacement of 1mm will occur between the first lens 31 and the second lens 32. Alternatively, the first lens 31 and the second lens 32 can also move in two directions that are set at an angle to each other, that is, the first lens 31 and the second lens 32 move in different directions and their directions of movement are not parallel, thus producing relative displacement. For example, the first lens 31 can move along the X-axis direction shown in the figure, and the second lens 32 can move along the Y-axis direction shown in the figure.

[0181] In other embodiments, optical focusing of the optical lens 1 can be achieved by moving either the first lens 31 or the second lens 32 separately. For example, the first lens 31 can be moved separately to change its focal length by changing its position, while the second lens 32 can remain fixed. In this case, the second lens 32 can be a liquid lens, a liquid crystal lens, or a similar type of lens. The focal length of the second lens 32 can be adjusted by changing the surface shape of its second freeform surface. A liquid lens is an optical element made of one or more liquids without mechanical connections. The internal parameters of the optical element can be changed by external control. Simply put, the medium of the lens changes from glass to liquid. More accurately, a liquid lens is a new type of optical element that dynamically adjusts the refractive index of the lens or changes the focal length by changing its surface shape. A liquid crystal lens is an optical element that adjusts the optical power by changing the voltage applied to the liquid crystal material, thereby changing the arrangement of the liquid crystal molecules and thus changing the refractive index distribution of the lens.

[0182] It should be noted that both the first lens 31 and the second lens 32 can change their focal length on the optical axis to achieve focusing of the optical lens 1, and both are zoom lenses.

[0183] Figure 6This is a schematic diagram illustrating the principle of a zoom lens in an optical system. (Refer to...) Figure 6 The optical system includes lenses W1 and W2 arranged sequentially along the optical axis. The distance between lenses W1 and W2 is m. The focal length of lens W1 is f′1, the focal length of lens W2 is f′2, the object distance of lens W1 is l1 (-l1 = l in the figure), the distance between lens W1 and the imaging plane is l′1 (l′1 = m + n in the figure), the object distance of lens W2 is l2, and the distance between lens W2 and the imaging plane is l′2 (l′2 = n in the figure).

[0184] In an optical system with only one zoom lens, assuming that one of lenses W1 and W2 is a zoom lens and the other is a fixed focal length lens, the following system of equations can be obtained using Gauss's formula:

[0185] -l1=l

[0186]

[0187] l2=l′1-n

[0188]

[0189] l′2=n

[0190] When lens W1 is a zoom lens and lens W2 is a fixed focal length lens, we can obtain:

[0191]

[0192] Since lens W2 is a fixed focal length lens, f2' does not change with other parameters, so the derivative of f2' is:

[0193]

[0194] Similarly, when lens W2 is a zoom lens and lens W1 is a fixed focal length lens, we can obtain:

[0195]

[0196] Differentiating f1', we get:

[0197]

[0198] It can be seen that the above equation can only be true when l or n is zero. However, the object distance l and the back intercept n cannot be zero. Therefore, an optical system using only a zoom lens cannot satisfy the condition that the image plane remains stationary.

[0199] For an optical system with two zoom lenses, i.e., both lens W1 and lens W2 are zoom lenses, the following system of equations can be obtained according to Gauss's formula:

[0200] -l1=l

[0201]

[0202] l2=l′1-m

[0203]

[0204] l′2=n

[0205]

[0206] In some cases, l1, m, and l2' are known quantities, so solving them yields equations for f2' and f' with respect to f1':

[0207]

[0208] This demonstrates that at least two zoom lenses are required in an optical system to achieve focusing. Therefore, in this embodiment, both the first lens 31 and the second lens 32 are provided with free-form curved surfaces, and the first lens 31 and the second lens 32 can generate relative displacement to achieve focusing of the optical lens 1.

[0209] Figure 7 yes Figure 4 The diagram shown is an equivalent optical path diagram of the optical lens 1 at an infinity object distance in one embodiment; Figure 8 yes Figure 4 The diagram shown is an equivalent optical path of the optical lens 1 at an object distance of 10 cm in one embodiment. Figure 7 Corresponding to the telephoto shooting mode of the 300 camera module, Figure 8 Corresponds to the macro shooting mode of camera module 300; refer to Figure 7 and Figure 8 During focusing, the first lens 31 and the second lens 32 move only in the direction perpendicular to the optical axis. That is, the second lens group 30 does not shift in the direction of the optical axis during focusing. Therefore, Figure 7 The distance between the first group of mirrors 10 and the second group of mirrors 30 is equal to Figure 8 The distance between the first mirror group 10 and the second mirror group 30 is such that the light path within the first prism 20 can be equivalent to... Figure 7 and Figure 8 The optical path within the interval between the first mirror group 10 and the second mirror group 30; reference Figure 4 Light rays emitted from the first mirror group 10 are reflected but not refracted after entering the first prism 20. Therefore, in Figure 7 and Figure 8 Within the interval between the first mirror group 10 and the second mirror group 30, light rays can be considered to travel in a straight line; (Refer to...)Figure 7 Light rays from a distant object enter optical lens 1 in a nearly parallel incident manner, as shown in the reference. Figure 8 Light rays from nearby objects enter the optical lens 1 in a manner similar to divergent light incidence. The first lens group 10 can converge parallel and divergent light, causing the light rays emitted from the first lens group 10 to gradually approach the center of the optical axis during propagation. Figure 7 and Figure 8 Within the interval between the first group of mirrors 10 and the second group of mirrors 30, the longer the propagation path of light, the closer it is to the optical axis, meaning the higher the degree of convergence between the light rays. The at least two reflections of light by the first prism 20 effectively extend the [propagation path]. Figure 7 and Figure 8 The distance between the first lens group 10 and the second lens group 30 makes the light rays entering the second lens group 30 converge more. As a result, the light rays need to pass through the second lens group 30 with smaller apertures, which can reduce the size of each lens in the second lens group 30.

[0210] The beneficial effects of the embodiments of this application are as follows:

[0211] A first free-form surface S1 is provided on the first lens 31, and a second free-form surface S2 is provided on the second lens 32. This changes the shape of the first lens 31 and the second lens 32, allowing the first lens 31 and the second lens 32 to move relative to each other in a direction perpendicular to the optical axis to achieve focusing. Compared with the traditional design of focusing by moving along the optical axis, the present embodiment requires a smaller focusing stroke in the direction perpendicular to the optical axis. Furthermore, in the direction perpendicular to the optical axis, the size of the first prism 20 usually constitutes a size bottleneck for the optical lens 1. That is, in the direction perpendicular to the optical axis, the first prism... Since the size of the lens 20 is usually larger than that of the lens, the smaller focusing stroke of the first lens 31 and the second lens 32 will not occupy extra or excessive space in the direction perpendicular to the optical axis. In this way, the size of the camera module 300 can be saved. Moreover, the first lens 31 and the second lens 32 do not shift in the direction of the optical axis. Therefore, the first lens 31 and the second lens 32 can be arranged more closely. This can reduce the total optical length of the optical lens 1 and further reduce the volume of the camera module 300, thereby facilitating the miniaturization and thinning design of the electronic device 1000.

[0212] Since the first prism 20 can reflect light from the first lens group 10 at least twice, it is equivalent to extending the propagation path of light within the first prism 20. Furthermore, the first lens group 10, which has positive optical power, has a converging effect on light. Thus, the light emitted from the first prism 20 is more convergent, and the light requires a smaller aperture when passing through the second lens group 30. Therefore, the size of the first lens 31 and the second lens 32 can be reduced, and the focusing stroke of the first lens 31 and the second lens 32 can be reduced accordingly. The empty area generated around the first lens 31 and the second lens 32 due to the reduction in size can compensate for the space required for the movement of the first lens 31 and the second lens 32. In this way, the space reserved for focusing within the optical lens 1 can be reduced or eliminated. This further reduces the space in the direction perpendicular to the optical axis occupied by the focusing stroke of the first lens 31 and the second lens 32, thereby saving the size of the camera module 300 and facilitating the miniaturization and thinning design of the electronic device 1000.

[0213] With the above settings, the first prism 20 reflects light at least twice, which can reduce the aperture required for light to pass through the second lens group 30, thereby reducing the size of the first lens 31 and the second lens 32, and reducing their focusing stroke. The smaller focusing stroke of the first lens 31 and the second lens 32 will not occupy extra or excessive space in the direction perpendicular to the optical axis, and the arrangement of the first prism 20 and the second lens group 30 in the optical axis direction can be more compact. In this way, the size of the camera module 300 can be saved in both the optical axis direction and the direction perpendicular to the optical axis, which is conducive to reducing the volume of the camera module 300, and thus brings convenience to the miniaturization and thinning design of the electronic device 1000.

[0214] In this embodiment, both the first lens 31 and the second lens 32 can move in a direction perpendicular to the optical axis. In some embodiments, a mechanical actuator (such as a focusing motor, not shown in the figure) can be provided in the camera module 300. The mechanical actuator is connected to the controller of the electronic device 1000 and drives the first lens 31 and the second lens 32 to move, thereby realizing the automatic focusing of the optical lens 1.

[0215] In some embodiments, the moving direction and moving distance of the first lens 31 and the second lens 32 can be designed by pre-calibration. For example, before the electronic device 1000 leaves the factory, the distance information that the first lens 31 and the second lens 32 need to move under different object distances is obtained by testing, and the relevant information parameters are recorded in the memory of the corresponding electronic device 1000. When taking pictures with the electronic device 1000, the camera module 300 of the electronic device 1000 can measure and obtain the actual object distance information, and then feed the actual object distance information back to the controller of the electronic device 1000. The controller and the memory work together to feed back the position movement information of the first lens 31 and the second lens 32 to the corresponding mechanical actuators, and the corresponding mechanical actuators drive the first lens 31 and the second lens 32 to move, thereby realizing the automatic focusing of the optical lens 1.

[0216] In some embodiments, the size of the largest optically effective area P1 of the second lens group 30 is D, and the relationship between D and the system image height (IMH) of the optical lens 1 satisfies the following formula: D / IMH≤1. Figure 9 This is a schematic diagram of the optically effective area P1 in the lens provided in the embodiments of this application, with reference to... Figure 9 In (a), the lens has an optically effective region P1 and an optically ineffective region P2 located around the optically effective region P1. The optically effective region P1 refers to the area of ​​the lens that achieves the expected optical performance. Within this region, the refraction, reflection, and transmission characteristics of light meet the design requirements, enabling clear imaging or specific optical functions such as focusing, collimation, and beam splitting. The quality and performance of this region play a crucial role in the imaging quality, resolution, and optical efficiency of the entire optical system. The optically ineffective region P2 refers to the area of ​​the lens that cannot effectively participate or will negatively affect the expected optical performance. This may include the edge portion of the lens. Surface defects, irregular shapes, and non-uniform refractive indices caused by manufacturing processes, installation errors, or other factors cause additional aberrations, scattering, or absorption when light passes through these areas, thereby reducing the performance of the optical system. In some designs, the optically ineffective region P2 may be blocked by a light shield or other structure to avoid its adverse effects on the optical system. (Refer to...) Figure 9 In (b), when two or more lenses are used in combination, the overlapping part of the optical effective area P1 between each lens will change as the position between the lenses changes. Thus, the size of the overall optical effective area P1 of the lens group will also change.

[0217] In this embodiment, during the focusing process, the movement of the lens changes the overlapping portion of the first lens 31 and the second lens 32, and changes the size of the optical effective area P1 of the second lens group 30. By setting the maximum optical effective area P1 size D of the second lens group 30 to be smaller than the system image height IMH of the optical lens 1, the optical effective area P1 of the first lens 31 and the second lens 32 can be appropriately reduced, thereby reducing the size of the first lens 31 and the second lens 32. In this way, there is a larger empty area around the first lens 31 and the second lens 32 to compensate for the space required for their movement, so that the space reserved for focusing within the optical lens 1 can be further reduced or eliminated, thereby reducing the overall size of the optical lens 1 and the size of the camera module 300, which is beneficial to achieving miniaturization and thinning of the electronic device 1000.

[0218] In some embodiments, one of the first lens 31 and the second lens 32 has a positive optical power and the other has a negative optical power, and the first lens 31 and the second lens 32 move in opposite directions; for example, the first lens 31 can be set to a positive optical power so that the first lens 31 can converge light, and the second lens 32 can be set to a negative optical power so that the second lens 32 can diverge light, or the first lens 31 can be set to a negative optical power and the second lens 32 can be set to a positive optical power. The first lens 31 and the second lens 32 are set to move in opposite directions. During the movement of the first lens 31 and the second lens 32, the optical axis position of the second lens group 30 remains unchanged, so that the center of the light rays entering the second lens group 30 can be kept in conjunction with the optical axis of the second lens group 30. The first lens 31 and the second lens 32 will deflect the direction of light propagation during the processing of light. The first lens 31 (or the second lens 32) with positive optical power can converge the light, while the second lens 32 (or the first lens 31) with negative optical power can diverge the light. The opposite processing of light by the first lens 31 and the second lens 32 will cause the first lens 31 and the second lens 32 to deflect the light in opposite directions. In this way, the first lens 31 and the second lens 32 can complement each other in adjusting the direction of light deflection, reducing the deviation between the light and the optical axis, reducing the off-axis aberration of the final image, and thus improving the imaging quality of the camera module 300.

[0219] Reference Figure 5In some embodiments, the first freeform surface S1 is located on the side of the first lens 31 closer to the second lens 32, and the second freeform surface S2 is located on the side of the second lens 32 closer to the first lens 31. This shortens the relative distance between the first freeform surface S1 and the second freeform surface S2. It is understood that after the light exits the first lens 31 and before it enters the second lens 32, the deviation of the light from the optical axis caused by the first lens 31 gradually increases. Shortening the relative distance between the first freeform surface S1 and the second freeform surface S2 can shorten the path of the light between the first freeform surface S1 and the second freeform surface S2. This reduces the deviation of the light from the optical axis after exiting the first lens 31 and before entering the second lens 32, reduces the difficulty of the second lens 32 in correcting the aberrations of the first lens 31, reduces the off-axis aberration in the final image, and thus improves the imaging quality of the camera module 300.

[0220] Of course, in some embodiments, the first freeform surface S1 can be disposed on the side of the first lens 31 away from the second lens 32, and the second freeform surface S2 can be disposed on the side of the second lens 32 away from the first lens 31.

[0221] Reference Figure 5 The first lens 31 also has a first surface G1 opposite to the first freeform surface S1. The first surface G1 can be a plane, a sphere, an aspherical surface or a freeform surface. Correspondingly, the second lens 32 also has a second surface G2 opposite to the second freeform surface S2. The second surface G2 can be a plane, a sphere, an aspherical surface or a freeform surface.

[0222] In some embodiments, the first freeform surface S1 and the second freeform surface S2 are both Alvarez freeform surfaces; in this case, the first lens 31 and the second lens 32 are both Alvarez lenses.

[0223] Figure 10 This is a schematic diagram of the principle of the Alvarez freeform surface provided in the embodiments of this application; see reference. Figure 10 To accurately define the parameters of the Alvarez freeform surface, a rectangular coordinate system with mutually perpendicular X, Y, and Z axes can be used. The Z-axis is the optical axis, the X-axis is the direction of lens movement, and the Y-axis is perpendicular to both the Z and X axes. The surface shape of the Alvarez freeform surface can be described by formula (1):

[0224]

[0225] Without changing the optical properties of the lens, in order to ensure that the thinnest part of the lens element has sufficient mechanical strength, a constant can be added to formula (1) to obtain the thickness expressions for the two Alvarez lenses:

[0226]

[0227] Where A and C are constants, and C ensures that the thinnest part of the lens element has sufficient mechanical strength; refer to Figure 10 In (a), when two Alvarez lenses are combined and there is no relative displacement between them, the combined thickness of the two Alvarez lenses is T = T1 + T2 = 2C. In this case, the combined effect of the two Alvarez lenses is equivalent to a parallel plate, which has no ability to deflect light.

[0228] Reference Figure 10 (b) and Figure 10 In equation (c), when the two Alvarez lenses move the same distance e in opposite directions, equations (2) and (3) change as follows:

[0229]

[0230] The thickness of the combined two Alvarez lenses is:

[0231]

[0232] Among them, -2Ae(y 2 +x 2 ) can be represented as a spherical surface with positive optical power, whose optical power is proportional to Ae. In addition, the other terms in formula (6) are independent of the values ​​of xy. Thus, it can be concluded that two Alvarez lenses can be combined to form a spherical mirror.

[0233] As can be seen from formula (6), the value of A determines the range of optical power variation at displacement e, and the equivalent focal length of the spherical mirror for the combination of two Alvarez lenses is:

[0234]

[0235] Where n is the refractive index of the lens material.

[0236] As can be seen from formula (7), the focal length of the spherical mirror equivalent to the combination of two Alvarez lenses can be changed with the displacement of the two Alvarez lenses. Thus, in this embodiment, the combined focal length of the first lens 31 and the second lens 32 can be adjusted during the movement of the first lens 31 and the second lens 32 along the direction perpendicular to the optical axis, so as to achieve focusing on different object distances.

[0237] It should be noted that the direction of movement of the Alvarez lens is related to its surface shape. The Alvarez lens defined by formula (1) needs to move along... Figure 10 The movement along the X-axis is shown. If we want to change the direction of movement of the Alvarez lens, for example, to set the direction of movement of the Alvarez lens to be along the Y-axis, then formula (1) can be adjusted as follows:

[0238]

[0239] Thus, by setting the first freeform surface S1 and the second freeform surface S2 as Alvarez freeform surfaces, their surface shape formulas can be determined based on their direction of movement, thereby reducing the design difficulty of the optical lens 1.

[0240] In embodiments of the electronic device 1000 where the camera module 300 is located on the front side of the display screen 200 or on the rear cover 1002, Figure 4 The X-axis direction corresponds to the width direction of electronic device 1000. Figure 4 The first direction in the diagram corresponds to the thickness direction of electronic device 1000. Figure 4 The second direction corresponds to the length direction of electronic device 1000.

[0241] In some embodiments, the moving direction of the first lens 31 and the second lens 32 is perpendicular to the light incident direction of the optical lens 1. For example, the light incident direction of the optical lens 1 may be along... Figure 4 In the first direction, the moving direction of the first lens 31 and the second lens 32 is perpendicular to the incident light direction of the optical lens 1 and the optical axis direction of the second lens group 30. Thus, the first lens 31 and the second lens 32 can move along the X-axis. At this time, the surface shape of the first free-form surface S1 and the second free-form surface S2 can be defined by formula (1). In the thickness direction of the electronic device 1000, the first lens 31 and the second lens 32 will not be displaced during focusing. Thus, in the thickness direction of the electronic device 1000, there is no need to reserve moving space for the first lens 31 and the second lens 32. This can reduce the space occupied by the first lens 31 and the second lens 32 in the thickness direction of the electronic device 1000, which is beneficial to reducing the thickness of the electronic device 1000.

[0242] Of course, in some embodiments, the first lens 31 and the second lens 32 can move along the Y-axis. In this case, the surface shape of the first freeform surface S1 and the second freeform surface S2 can be defined by formula (8). In this embodiment, the first lens 31 and the second lens 32 will not be displaced during focusing in the width direction of the electronic device 1000. Thus, there is no need to reserve moving space for the first lens 31 and the second lens 32 in the width direction of the electronic device 1000. This can reduce the space occupied by the first lens 31 and the second lens 32 in the width direction of the electronic device 1000, which is beneficial to reduce the width of the electronic device 1000.

[0243] Of course, in other embodiments, the first lens 31 and the second lens 32 may also move along the angle between the X-axis and the Y-axis.

[0244] In this embodiment, the first lens 31 and the second lens 32 move along the X-axis. At this time, the moving direction of the first lens 31 and the second lens 32 is perpendicular to the plane formed by the Z-axis and the Y-axis and parallel to the plane formed by the X-axis and the Y-axis. The first freeform surface S1 and the second freeform surface S2 are both Alvarez freeform surfaces.

[0245] It should be noted that during the focusing process, the first lens 31 and the second lens 32 move in opposite directions. The movement values ​​of the first lens 31 and the second lens 32 can be equal or unequal. For example, when the movement value of the first lens 31 is 3mm, the movement value of the second lens 32 can be 3mm or 4mm.

[0246] In other embodiments, the first freeform surface S1 and the second freeform surface S2 can also be freeform surfaces other than the Alvarez freeform surface, that is, the first lens 31 and the second lens 32 can also be lenses other than the Alvarez lens. For example, the first lens 31 and the second lens 32 can also be Lohmann lenses. Of course, the first freeform surface S1 on the first lens 31 and the second freeform surface S2 on the second lens 32 can also be defined by other surface formulas.

[0247] In some embodiments, the second lens group 30 further includes a third lens 33, which has a third free-form surface S3. The third lens 33, located in the second lens group 30, can process light. Its proximity to the first lens 31 and the second lens 32 reduces the difficulty of aberration correction and improves the imaging quality of the camera module 300. The third lens 33 increases the number of lenses within the second lens group 30, thus supplementing light processing by increasing the number of lenses. This reduces the light processing burden on the first lens 31 and the second lens 32, thereby reducing lens sensitivity and improving the stability of the optical lens 1.

[0248] In some embodiments, the third lens 33 may be a lens with positive optical power or a lens with negative optical power.

[0249] In some embodiments, the second lens group 30 has negative optical power. In this embodiment, the first lens group 10 has positive optical power. The second lens group 30 with negative optical power is used in conjunction with the first lens group 10 with positive optical power to balance the optical path, making the overall structure of the optical lens 1 more compact and reducing the length and volume of the optical lens 1. In addition, it can also improve the sharpness and contrast of the optical lens 1, making the image sharper and more delicate.

[0250] In some embodiments, the optical power of the first lens group 10 is fixed. That is, light rays with different incident angles undergo essentially the same deflection angle after being converged by the first lens group 10. When shooting close-up objects (i.e., macro mode), the light rays are incident in a manner that is approximately divergent, while when shooting distant objects (i.e., telephoto mode), the light rays are incident in a manner that is approximately parallel. (Refer to...) Figure 7 and Figure 8 Within the interval between the first lens group 10 and the second lens group 30, the angle formed by the light rays of distant objects and the optical axis will be greater than the angle formed by the light rays of nearby objects and the optical axis.

[0251] In some embodiments, the focal length of the second lens group 30 is F3 in telephoto shooting mode and F4 in macro shooting mode, and the optical lens 1 satisfies the following relationship: |F3| < |F4|. It is understood that, referring to... Figure 7 In telephoto shooting mode, light rays from distant objects are incident in an approximately parallel manner, referring to... Figure 8In macro shooting mode, light from close-range objects is incident in a manner that is approximately divergent. Without changing the focal length of the optical lens 1, the intersection points of the two types of light rays are different, resulting in different positions of the imaging surface. This necessitates adjusting the position of the image sensor 60. However, to ensure that the image sensor 60 can receive all the light processed by the optical lens 1, its size is typically set relatively large. If a movable image sensor 60 is used, the camera module 300 would require a larger space, which is not conducive to the miniaturization and thinning of the electronic device 1000. To fix the position of the imaging surface of the camera module 300, the focal length of the second lens group 30 can be adjusted, ensuring that the position of the imaging surface of the camera module 300 remains essentially unchanged at different object distances, thus reducing the movement of the image sensor. (Refer to...) Figure 8 In macro shooting mode, light enters in a manner that is approximately divergent. This reduces the divergence of light by the second lens group 30. (Refer to...) Figure 7 In telephoto shooting mode, light enters in a nearly parallel manner, which enhances the light-diverging ability of the second lens group 30. For the second lens group 30 with negative optical power, the weaker its light-diverging ability, the larger its optical power value (i.e., the smaller the absolute value of the optical power value). Numerically, focal length and optical power have an inverse relationship; the smaller the absolute value of the optical power value, the larger the absolute value of the focal length value. Therefore, the light-diverging ability of the second lens group 30 can be adjusted by changing the focal length. (Refer to...) Figure 8 In macro shooting mode, the absolute value of the 30mm focal length of the second lens group can be increased; refer to Figure 7 In telephoto shooting mode, the absolute value of the focal length of the second lens group 30 can be reduced. That is, the absolute value of the focal length of the second lens group 30 in telephoto shooting mode is set to be smaller than that in macro shooting mode. This makes the light-diffusing ability of the second lens group 30 stronger in telephoto shooting mode than in macro shooting mode. In this way, the optical lens 1 can be focused, so that the position of light rays at different object distances on the imaging surface within the camera module 300 remains basically unchanged. Thus, even if the movement of the image sensor 60 is reduced or not moved, the light rays can still converge on the image sensor 60 and form a clear image on the image sensor 60.

[0252] In some embodiments, the combined focal length of the first lens 31 and the second lens 32 is F1, and the focal length of the second lens group 30 is F2, where |F1|>2|F2|.

[0253] It should be noted that the combined focal length of the first lens 31 and the second lens 32 can be understood as the equivalent focal length exhibited when the first lens 31 and the second lens 32 are used together. The refraction effect of light after passing through the first lens 31 and the second lens 32 can be equivalent to a single lens with a specific focal length. The focal length of this equivalent lens is the combined focal length of the first lens 31 and the second lens 32.

[0254] The focal length of the second lens group 30 is the combined focal length of all lenses within the second lens group 30. In this embodiment, the second lens group 30 includes a first lens 31, a second lens 32, and a third lens 33. Therefore, the focal length of the second lens group 30 is equivalent to the combined focal length of the first lens 31, the second lens 32, and the third lens 33. The combined focal length F1 of the first lens 31 and the second lens 32 can be positive, in which case the focal length of the third lens 33 can be negative. Conversely, the combined focal length F1 of the first lens 31 and the second lens 32 can also be negative, in which case the focal length of the third lens 33 can be positive. It is understood that for a lens with negative optical power, the larger the absolute value of its focal length, the weaker its ability to diverge light; for a lens with positive optical power, the larger the value of its focal length, the weaker its ability to diverge light. The weaker the light-gathering ability, the stronger the light-gathering divergence / convergence ability of a lens, the greater the deflection of the light's propagation direction after passing through the lens, and the greater the aberration caused by the lens. In other words, the lens has a greater impact on the final image quality. Therefore, by setting the absolute value of the combined focal length of the first lens 31 and the second lens 32 to be greater than twice the absolute value of the focal length of the second lens group 30, the light-gathering divergence / convergence ability of the first lens 31 and the second lens 32 can be controlled to reduce the aberrations caused by the first lens 31 and the second lens 32, thereby reducing the impact of a single lens on the final imaging effect. In addition, the aberrations generated by the first lens 31 and the second lens 32 can also be corrected by the third lens 33, which can reduce the aberrations generated by the second lens group 30 and improve the imaging effect of the camera module 300.

[0255] In this embodiment, the second lens group 30 is provided with three lenses (i.e., the first lens 31, the second lens 32 and the third lens 33). In other embodiments, the second lens group 30 may also be provided with four, five or even more lenses. In addition, the number of Alvarez lenses in the second lens group 30 is not limited to two. For example, the third lens 33 may also be an Alvarez lens. In this case, the third freeform surface S3 may also be an Alvarez freeform surface.

[0256] In some embodiments, reference is made to Figure 5The third lens 33 is located on the side of the first lens 31 away from the second lens 32. In this case, light passes through the third lens 33, the first lens 31, and the second lens 32 in sequence. Alternatively, the third lens 33 can be located on the side of the second lens 32 away from the first lens 31. In this case, light passes through the first lens 31, the second lens 32, and the third lens 33 in sequence. Placing the third lens 33 on one side of the paired first lens 31 and second lens 32 can shorten the distance between the first lens 31 and the second lens 32, thereby improving the focusing effect of the optical lens 1 and the imaging quality of the camera module 300. In this embodiment, the third free-form surface S3 of the third lens 33 can be facing towards the first lens 31 or away from the first lens 31.

[0257] Of course, in some other embodiments, the third lens 33 is located between the first lens 31 and the second lens 32. In this case, light passes through the first lens 31, the third lens 33, and the second lens 32 in sequence. Thus, the distance between the third lens 33 and the first lens 31 and the second lens 32 is small, and the third lens 33 can better correct the aberrations produced by the first lens 31 and the second lens 32. The positional relationship between the third lens 33 and the first lens 31 and the second lens 32 can be set according to actual needs, and this embodiment does not impose any limitations. In this embodiment, the third freeform surface S3 of the third lens 33 can face the first lens 31 or the second lens 32.

[0258] In some embodiments, the third lens 33 further has a third surface G3 opposite to the third freeform surface S3, and the third surface G3 may be a plane, a sphere, an aspherical surface or a freeform surface.

[0259] In some embodiments, refer to Figure 7 and Figure 8 The third lens 33 is fixed, meaning that it will not move during the focusing process.

[0260] Figure 11 yes Figure 4 The diagram shown illustrates the modulation transfer function (MTF) of the optical lens 1 at infinity in one embodiment. Figure 12 yes Figure 4 The modulation transfer function graph of the optical lens 1 shown in one embodiment at an object distance of 10 cm is as follows. Figure 13 yes Figure 4 The diagram shown illustrates the imaging distortion of the optical lens 1 in one embodiment; wherein, Figure 11 This is the defocusing MTF curve of the optical lens 1 in this embodiment at a spatial frequency of 100 lp / mm at an infinity object distance. Figure 11It can be seen that the modulation transfer function (MTF) at infinity object distances under different fields of view is concentrated between 0.4 and 0.8, which indicates that... Figure 4 The optical lens 1 shown can achieve high-quality imaging at infinity object distance when the third lens 33 is kept fixed, that is, the optical lens 1 can achieve high-quality imaging in telephoto shooting mode. Figure 12 This is the defocusing MTF curve of the optical lens 1 in this embodiment at a spatial frequency of 100 lp / mm at an object distance of 10 cm. Figure 12 It can be seen that the modulation transfer function (MTF) at different fields of view with an object distance of 10 cm is concentrated between 0.5 and 0.8. This result indicates that... Figure 4 The optical lens 1 shown can achieve high-quality imaging at an object distance of 10cm when the third lens 33 is kept fixed, that is, the optical lens 1 can achieve high-quality imaging in macro shooting mode; Figure 13 It can be seen that the paraxial FOV of the optical lens 1 in this embodiment differs little from the actual FOV, which indicates that... Figure 4 With the third lens 33 fixed, the optical lens 1 shown exhibits minimal distortion in its imaging; thus, Figure 4 With the third lens 33 fixed, the optical lens 1 shown can produce high-quality images in both telephoto and macro shooting modes.

[0261] The relevant parameters of the camera module 300, which includes the optical lens 1 of this embodiment, can be described in conjunction with Table 1.

[0262] Table 1: Basic Parameters of Camera Module (Third Lens Fixed)

[0263]

[0264] Figure 14 yes Figure 4 The diagram shown is an equivalent optical path diagram of the optical lens 1 at infinity object distance in another embodiment. Figure 15 yes Figure 4 The optical lens 1 shown is illustrated in another embodiment with an equivalent optical path diagram at an object distance of 10 cm; see reference. Figure 14 and Figure 15 In other embodiments, the third lens 33 is movable in a direction perpendicular to the optical axis of the second lens group 30. That is, during the process of the first lens 31 and the second lens 32 moving to achieve focusing, the third lens 33 can also move in a direction perpendicular to the optical axis to generate displacement.

[0265] In some embodiments, a mechanical actuator (such as a focusing motor) may be provided within the camera module 300 to drive the third lens 33 to move.

[0266] In some embodiments, the moving direction and moving distance of the first lens 31, the second lens 32, and the third lens 33 can be designed using a pre-calibration method. For example, before the electronic device 1000 leaves the factory, the distance that the first lens 31, the second lens 32, and the third lens 33 need to move under different object distances is obtained through testing, and the relevant parameters are recorded in the memory of the corresponding electronic device 1000. When taking pictures using the electronic device 1000, the camera module 300 of the electronic device 1000 can measure the object distance information and then feed the object distance information back to the controller of the electronic device 1000. The controller and the memory work together to feed back the position movement information of the first lens 31, the second lens 32, and the third lens 33 to the corresponding mechanical actuators, which then drive the first lens 31, the second lens 32, and the third lens 33 to move, thereby realizing the automatic focusing of the camera module 300.

[0267] Figure 16 yes Figure 4 The modulation transfer function diagram of optical lens 1 at infinity object distance in another embodiment is shown. Figure 17 yes Figure 4 The diagram shown is a schematic of the modulation transfer function of the optical lens 1 at an object distance of 10 cm in another embodiment. Figure 18 yes Figure 4 The diagram shows an imaging distortion of the optical lens 1 in another embodiment; wherein, Figure 16 This is the defocusing MTF curve of the optical lens 1 in this embodiment at a spatial frequency of 100 lp / mm at an infinity object distance. Figure 16 It can be seen that the modulation transfer function (MTF) at infinity object distances under different fields of view is concentrated between 0.4 and 0.8, which indicates that... Figure 4 The optical lens 1 shown can achieve high-quality imaging at infinity object distance when the third lens 33 is movable, that is, the optical lens 1 can achieve high-quality imaging in telephoto shooting mode. Figure 17 This is the defocusing MTF curve of the optical lens 1 in this embodiment at a spatial frequency of 100 lp / mm at an object distance of 10 cm. Figure 17 It can be seen that the modulation transfer function (MTF) at different fields of view with an object distance of 10 cm is concentrated between 0.5 and 0.8. This result indicates that... Figure 4 The optical lens 1 shown can achieve high-quality imaging at an object distance of 10cm when the third lens 33 is movable, that is, the optical lens 1 can achieve high-quality imaging in macro shooting mode; compared to Figure 13 , Figure 18 The paraxial FOV shown is smaller than the actual FOV, indicating that the movable third lens 33 can reduce the distortion of the image formed by the optical lens 1 compared to the case where the third lens 33 is fixed; thus, Figure 4With the third lens 33 movable, the optical lens 1 shown can achieve higher quality imaging in both telephoto and macro shooting modes.

[0268] In some embodiments, the moving direction of the third lens 33 may be parallel to the moving direction of the first lens 31. In other embodiments, the moving direction of the third lens 33 may not be parallel to the moving direction of the first lens 31, that is, the moving direction of the third lens 33 is set at an angle to the moving direction of the first lens 31.

[0269] Figure 19 yes Figure 5 A schematic diagram of the A-direction viewing angle of the third lens 33 in the second lens group 30 shown. In this embodiment, refer to... Figure 5 and Figure 19 The moving direction of the third lens 33 is perpendicular to the incident light direction of the optical lens 1. The free-form curved surface of the third lens 33 is symmetrical about the first axis of symmetry 34. The straight line direction of the first axis of symmetry 34 is set at an angle to the moving direction of the third lens 33. As can be seen from the surface shape formula of the Alvarez freeform surface, the Alvarez freeform surface has a symmetrical relationship. In this embodiment, the first freeform surface S1 and the second freeform surface S2 are defined by formula (1). In some embodiments, the first lens 31, the second lens 32 and the third lens 33 all move along the X direction shown in the figure. The first freeform surface S1 and the second freeform surface S2 are symmetrical about the plane formed by the X axis shown in the figure and the optical axis of the second lens group 30. The first axis of symmetry 34 is set at an angle to the plane formed by the X axis shown in the figure and the optical axis of the second lens group 30. The axis of symmetry of the third freeform surface S3 is not parallel to the axis of symmetry of the first freeform surface S1 (which is also the axis of symmetry of the second freeform surface S2). During the movement of the third lens 33, the relative position of the first axis of symmetry 34 and the axis of symmetry of the first freeform surface S1 (which is also the axis of symmetry of the second freeform surface S2) will change. In this way, the third lens 33 can correct the aberrations generated by the first lens 31 and the second lens 32 by moving its own position.

[0270] In this embodiment, the straight line direction of the first axis of symmetry 34 can be perpendicular to the moving direction of the third lens 33. That is, the first axis of symmetry 34 can be perpendicular to the plane formed by the X-axis and the optical axis of the second lens group 30, and parallel to the plane formed by the Y-axis and the optical axis of the second lens group 30. For example, the first axis of symmetry 34 can extend along the Y-axis direction.

[0271] The relevant parameters of the camera module 300, which includes the optical lens 1 of this embodiment, can be described in conjunction with Table 2.

[0272] Table 2: Basic Parameters of Camera Module (Third Lens is Movable)

[0273]

[0274] In some embodiments, the first lens group 10 includes a sixth lens (not shown in the figure). The surface of the sixth lens can be spherical or aspherical, that is, the surface of the sixth lens can be spherical or aspherical with a rotation axis. The sixth lens can process the light entering the first lens group 10 to reduce aberrations and improve the imaging quality of the camera module 300. The first lens group 10 can also be provided with a seventh lens, an eighth lens, etc. The surface of these lenses can be spherical or aspherical with a rotation axis and central symmetry. In this way, the first lens group 10 has multiple lenses to process the light.

[0275] Figure 20 yes Figure 4 A schematic diagram of the first lens group 10 in the optical lens 1 shown; refer to Figure 20 In other embodiments, the first lens group 10 includes a fourth lens 11, which has a fourth free-form surface S4. The fourth lens 11 can converge the light rays entering the optical lens 1, so that the light rays entering the first prism 20 can gradually approach the optical axis during propagation, reducing the aperture required for the light rays to pass through the second lens group 30; by providing the fourth free-form surface S4 on the fourth lens 11, the fourth lens 11 can process the light rays to reduce aberrations and improve the imaging quality of the camera module 300.

[0276] In some embodiments, the fourth lens 11 further has a fourth surface G4 opposite to the fourth freeform surface S4. The fourth surface G4 can be a plane, a spherical surface, an aspherical surface, or a freeform surface. The fourth freeform surface S4 of the fourth lens 11 can be disposed on the object side of the fourth lens 11 or on the image side of the fourth lens 11. Figure 20 The fourth free-form surface S4 is located on the object side of the fourth lens 11.

[0277] Figure 21 yes Figure 20 A schematic diagram of the B-direction viewing angle of the fourth lens 11 and the fifth lens 12 in the first lens group 10 shown; refer to Figure 20 and Figure 21The fourth free-form surface S4 is symmetrical about the second axis of symmetry 35. The first lens group 10 also includes a fifth lens 12, which has a fifth free-form surface S5. The fifth free-form surface S5 is symmetrical about the third axis of symmetry 36. The direction of the second axis of symmetry 35 and the direction of the third axis of symmetry 36 are set at an angle, that is, the direction of the second axis of symmetry 35 and the direction of the third axis of symmetry 36 are not parallel. The fifth lens 12 can converge the light rays entering the optical lens 1. In this way, the fifth lens 12 and the fourth lens 11 can be used together to appropriately reduce the optical power of the fourth lens 11, thereby weakening the ability of the fourth lens 11 to converge light rays and reducing the deflection of the light rays when passing through the fourth lens 11, thereby reducing the aberrations caused by the fourth lens 11. By setting the direction of the second axis of symmetry 35 and the direction of the third axis of symmetry 36 at an angle, the fourth lens 11 and the fifth lens 12 can correct the aberrations of the optical lens 1 from different directions, thus improving the imaging quality of the camera module 300.

[0278] In some embodiments, the direction of the line containing the second axis of symmetry 35 is perpendicular to the direction of the line containing the third axis of symmetry 36. For example, refer to Figure 20 and Figure 21 The second axis of symmetry can be parallel to the X-axis, and the third axis of symmetry can be perpendicular to the X-axis. Of course, in other embodiments, the third axis of symmetry can be parallel to the X-axis, and the second axis of symmetry can be perpendicular to the X-axis.

[0279] In some embodiments, the fifth lens 12 further has a fifth surface G5 opposite to the fifth freeform surface S5. The fifth surface G5 can be a plane, a spherical surface, an aspherical surface, or a freeform surface. The fifth freeform surface S5 of the fifth lens 12 can be disposed on the object side of the fifth lens 12 or on the image side of the fifth lens 12. Figure 20 The fifth free-form surface S5 is located on the image side of the fifth lens 12, and the fifth surface G5 of the fifth lens 12 is positioned opposite to the fourth surface G4 of the fourth lens 11.

[0280] In some embodiments, the focal length of the first lens group 10 is F5, and the focal length of the optical lens 1 is F6. The optical lens 1 satisfies the following relationship: 0.2 ≤ F5 / F6 ≤ 5. The focal length of the first lens group 10 is the combined focal length of all lenses within the first lens group 10, and the focal length of the optical lens 1 is the combined focal length of all lenses within the optical lens 1. In this embodiment, the first lens group 10 includes a fourth lens 11 and a fifth lens 12, and the focal length of the first lens group 10 is the combined focal length of the fourth lens 11 and the fifth lens 12. The optical lens 1 includes a first lens 31, a second lens 32, a third lens 33, a fourth lens 11, and a fifth lens 12, and the focal length of the optical lens 1 is the combined focal length of the first lens 31, the second lens 32, the third lens 33, the fourth lens 11, and the fifth lens 12. The optical lens 1 needs to converge light so that the light can be imaged on the image sensor 60; therefore, the optical lens 1 has positive optical power. By setting the ratio of the focal length of the first lens group 10 to the focal length of the optical lens 1 between 0.2 and 5, the focal length of the first lens group 10 can be controlled, thereby controlling the optical power of the first lens group 10, reducing the aberrations caused by the first lens group 10, and improving the imaging effect of the camera module 300.

[0281] In some embodiments, the focal length F6 of the optical lens 1 can be designed as needed; for example, the value of F6 can be 20 to 25.

[0282] Reference Figure 4 The optical lens 1 also includes a second prism 40, located on the image side of the second mirror group 30. The second prism 40 is used to reflect light from the second mirror group 30. The second prism 40 can reflect light from the second mirror group 30, thereby changing the direction of light propagation. This allows adjustment of the orientation of the image sensor 60. For example, the surface of the image sensor 60 used to receive light (this surface is typically the largest surface area of ​​the image sensor 60) can be aligned parallel to the width direction (X-axis direction in the diagram) and length direction of the electronic device 1000. Figure 4 The second direction shown is configured such that the surface of the image sensor 60 used to receive light can be aligned with the thickness direction of the electronic device 1000. Figure 4 The first direction shown is perpendicular to the image sensor 60, which reduces the space occupied by the image sensor 60 in the thickness direction of the electronic device 1000, and is conducive to reducing the thickness of the electronic device 1000.

[0283] Of course, in some embodiments, the image sensor 60 may also be tilted, that is, the image sensor 60 may be tilted relative to the width direction (X-axis direction in the figure) and length direction (in the electronic device 1000). Figure 4 The plane formed by the second direction shown is set at an angle.

[0284] Continue to refer to Figure 4In some embodiments, the first prism 20 includes a first side surface 21, a second side surface 22, and a third side surface 23. The angle between the first side surface 21 and the second side surface 22 is less than 45°. Light rays from the first mirror group 10 are incident on the first side surface 21, reflected sequentially by the second side surface 22 and the first side surface 21, and exit from the third side surface 23. The angle between the first side surface 21 and the second side surface 22 can be denoted as the first angle, corresponding to angle α in the figure, where α < 45°. It should be noted that the first side surface 21 is the surface where light transmission and total internal reflection occur. It transmits light rays from the first mirror group 10, which are reflected by the second side surface 22 and then incident on the first side surface 21 again, where total internal reflection occurs. The reflected light finally exits the first prism 20 through the third side surface 23. A reflective coating can be applied to the second side surface 22 to improve its reflectivity.

[0285] It should be noted that the value of the first included angle α is related to the refractive index of the first prism 20. To satisfy total internal reflection, the first included angle α and the refractive index n1 of the first prism 20 can satisfy the following relationship: n1≥1 / sin(2α). In a conventional folding lens system, the angle between the first side surface 21 and the second side surface 22 of the first prism 20 is usually 45°. In this embodiment, the angle between the first side surface 21 and the second side surface 22 of the first prism 20 is set to be less than 45°, which helps to reduce the impact of the optical lens 1 on the refractive index. Figure 4 The dimension in the first direction (i.e., the thickness direction of the electronic device 1000) shown helps to reduce the dimension of the camera module 300 in the thickness direction of the electronic device 1000, which is beneficial to reducing the thickness of the electronic device 1000.

[0286] In the above embodiments, the first prism 20 is a non-45° prism. In other embodiments, the first prism 20 can also be selected from other types of prisms to achieve at least two reflections of light. For example, a Schmidt-Pechan prism, an Abbe-Koenig prism, or a Porro prism can be selected.

[0287] In some embodiments, the second prism 40 includes a fourth side surface 41, a fifth side surface 42, and a sixth side surface 43. The angle between the fifth side surface 42 and the sixth side surface 43 is less than 45°. Light rays from the second mirror group 30 are incident on the fourth side surface 41, reflected sequentially by the fifth side surface 42 and the fourth side surface 41, and exit from the sixth side surface 43. The angle between the fifth side surface 42 and the sixth side surface 43 can be denoted as the second angle, corresponding to angle β in the figure, where β < 45°. It should be noted that the fourth side surface 41 is the surface where light transmission and total internal reflection occur. It transmits light rays from the second mirror group 30, which are reflected by the fifth side surface 42 and then incident on the fourth side surface 41 again, where total internal reflection occurs. The reflected light finally exits the second prism 40 through the sixth side surface 43. A reflective coating can be applied to the fifth side surface 42 to enhance its reflectivity.

[0288] It should be noted that the value of the second included angle β is related to the refractive index of the second prism 40. In order to satisfy total internal reflection, the second included angle β and the refractive index n2 of the second prism 40 can satisfy the following relationship: n2≥1 / sin(2β). Setting the angle between the fifth side surface 42 and the sixth side surface 43 of the second prism 40 to be less than 45° helps to reduce the size of the optical lens 1 in the first direction shown in the figure (i.e., the thickness direction of the electronic device 1000), thereby helping to reduce the size of the camera module 300 in the thickness direction of the electronic device 1000, which is beneficial to reducing the thickness of the electronic device 1000.

[0289] In the above embodiments, the second prism 40 is a non-45° prism. In other embodiments, the second prism 40 can also be selected from other types of prisms to achieve at least two reflections of light. For example, a Schmidt-Pechan prism, an Abbe-Koenig prism, or a Porro prism can be selected.

[0290] In some embodiments, both the first prism 20 and the second prism 40 can be non-45° prisms.

[0291] In some embodiments, the first included angle and the second included angle are equal in size, so that light rays can travel along... Figure 4 The light emitted from the second prism 40 is emitted in the first direction (corresponding to the thickness direction of the electronic device 1000). At this time, the surface of the image sensor 60 used to receive light (this surface is usually the surface with the largest area of ​​the image sensor 60) can be positioned parallel to the width direction (X-axis direction in the figure) and length direction of the electronic device 1000. Figure 4 The second direction shown is configured such that the surface of the image sensor 60 used to receive light can be aligned with the thickness direction of the electronic device 1000. Figure 4The first direction shown is perpendicular to the image sensor 60, which reduces the space occupied by the image sensor 60 in the thickness direction of the electronic device 1000, and is conducive to reducing the thickness of the electronic device 1000.

[0292] For example, the ranges of α and β can be: 0°<α=β<10°, 10°≤α=β<20°, 20°≤α=β<25°, 25°≤α=β<30°, 30°≤α=β<35°, 35°≤α=β<40°, and 40°≤α=β<45°.

[0293] For example, the ranges of α and β can be: 22° < α = β < 28°.

[0294] In some embodiments, the third side surface 23 of the first prism 20 may be a surface with optical power, so that the first prism 20 has the ability to converge / diverge light, and thus the first prism 20 can correct aberrations.

[0295] In some embodiments, the fourth side surface 41 of the second prism 40 may be a surface with optical power, so that the second prism 40 has the ability to converge / diverge light, and thus the second prism 40 can correct aberrations.

[0296] Reference Figure 4 The aperture stop 50 of the optical lens 1 can be disposed on the object side of the first lens group 10. In other embodiments, the aperture stop 50 can be disposed between the first lens group 10 and the first prism 20, or between the first prism 20 and the second lens group 30, or between the second lens group 30 and the second prism 40. This application does not limit this to any particular embodiment.

[0297] This application provides a camera module 300, which includes an image sensor 60 and an optical lens 1 as described in any of the above embodiments. The optical lens 1 is used to image the scene on the object side onto the image sensor 60. Since the overall size of the optical lens 1 in any of the above embodiments is small, the camera module 300 including this optical lens 1 is small in size and occupies less space in the electronic device 1000, which is beneficial to the miniaturization and thinning of the electronic device 1000.

[0298] This application provides a possible design for a camera module 300:

[0299] Reference Figure 4The camera module 300 includes an aperture stop 50, a first lens group 10, a first prism 20, a second lens group 30, a second prism 40, a filter 70, and an image sensor 60 arranged sequentially from the object side to the image side. The first lens group 10 includes a fourth lens 11 and a fifth lens 12. The fourth freeform surface S4 of the fourth lens 11 and the fifth freeform surface S5 of the fifth lens 12 are arranged opposite to each other, that is, the fourth surface G4 of the fourth lens 11 and the fifth surface G5 of the fifth lens 12 are arranged facing each other. The fourth freeform surface S4 is symmetrical about a second axis of symmetry 35, and the fifth freeform surface S5 is symmetrical about a third axis of symmetry 36. The second axis of symmetry 35 and the third axis of symmetry 36 are perpendicular. The second lens group 30 includes a first lens 31, a second lens 32, and a third lens 33. The first lens 31... 1. Both the second lens 32 and the third lens 33 can move along the X-axis direction shown in the figure, and the first lens 31 and the second lens 32 move in opposite directions. The first freeform surface S1 of the first lens 31 and the second freeform surface S2 of the second lens 32 are arranged opposite to each other, and both the first freeform surface S1 and the second freeform surface S2 are Alvarez freeform surfaces. The third lens 33 is located on the image side of the first lens 31. The third freeform surface S3 of the third lens 33 is arranged facing the first lens 31, and the third freeform surface S3 is symmetrical about the first axis of symmetry 34. The angle α between the first side surface 21 and the second side surface 22 of the first prism 20 is equal in size to the angle β between the fifth side surface 42 and the sixth side surface 43 of the second prism 40, and 22° < α = β < 28°.

[0300] Reference Figure 4 In this embodiment of the application, the surface of the image sensor 60 of the camera module 300 used to receive light (this surface is typically the surface with the largest area of ​​the image sensor 60) is parallel to... Figure 4 Figure 4 The X-axis direction is set as shown, so that the thickness direction of the image sensor 60 is consistent with the thickness direction of the electronic device 1000. This can reduce the space occupied by the image sensor 60 in the thickness direction of the electronic device 1000, which is conducive to the miniaturization and thinning of the electronic device 1000.

[0301] This application provides an electronic device 1000, which includes an image processor and a camera module 300 as described in any of the above embodiments. The camera module 300 is used to acquire image data and input the image data into the image processor, which is used to process the image data. Since the camera module 300 in any of the above embodiments is small in size and occupies little space within the electronic device 1000, this embodiment can reduce the volume of the electronic device 1000, achieving miniaturization and thinning.

[0302] In this embodiment, when the electronic device 1000 is used for shooting, the first prism 20 of the optical lens 1 within the electronic device 1000 can reflect the light entering the camera module 300 at least twice. This improves the convergence of the light emitted from the first prism 20 and reduces the aperture required for the light to pass through the second lens group 30. This reduces the size of the first lens 31 and the second lens 32. Due to the reduced size, the first lens 31 and the second lens 32 have a periphery with a void area. This void area can compensate for the space required for the movement of the first lens 31 and the second lens 32, thus reducing the extra space reserved for the first lens 31 and the second lens 32 when moving to focus. In addition, the first prism 20 reflects the light from the first lens group 10 at least twice, which can reduce the size of the second lens group 30. The reduction in the light-transmitting aperture can also reduce the movement of the first lens 31 and the second lens 32 during focusing, that is, reduce the focusing distance of the first lens 31 and the second lens 32. In this way, the space reserved for focusing can be reduced or eliminated within the optical lens 1. Since the first lens 31 and the second lens 32 do not shift in the direction, the first prism 20 and the second lens group 30 can be arranged more closely along the optical axis to reduce the size of the optical lens 1. In the direction perpendicular to the optical axis, the empty area around the first lens 31 and the second lens 32 can compensate for the space required for their movement. Therefore, the space reserved for focusing can be reduced or eliminated within the optical lens 1, which is beneficial to the miniaturization and thinning of the electronic device 1000.

[0303] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical lens characterized in that, The first mirror group (10), the first prism (20) and the second mirror group (30) are sequentially arranged from the object side to the image side; The first mirror group (10) has positive focal power; The first prism (20) is used for reflecting light from the first mirror group (10) at least twice; The second mirror group (30) is used for receiving light emitted from the first prism (20), and includes a first lens (31) and a second lens (32) sequentially arranged along the optical axis direction, the first lens (31) has a first free-form surface (S1), the second lens (32) has a second free-form surface (S2), and the first lens (31) and the second lens (32) can be relatively displaced in a direction perpendicular to the optical axis of the second mirror group (30) to realize optical focusing of the optical lens (1).

2. The optical lens of claim 1, wherein, The moving direction of the first lens (31) and the second lens (32) is perpendicular to the light entering direction of the optical lens (1).

3. The optical lens according to claim 1 or 2, characterized in that, The first free-form surface (S1) and the second free-form surface (S2) are both Alvarez free-form surfaces.

4. The optical lens according to any one of claims 1 to 3, characterized in that, One of the first lens (31) and the second lens (32) has positive focal power, and the other has negative focal power, and the moving direction of the first lens (31) and the second lens (32) is opposite.

5. The optical lens according to any one of claims 1 to 4, characterized in that, The second mirror group (30) further includes a third lens (33) having a third free-form surface (S3).

6. The optical lens of claim 5, wherein, The third lens (33) is movable in a direction perpendicular to the optical axis of the second mirror group (30).

7. The optical lens of claim 6, wherein, The moving direction of the third lens (33) is perpendicular to the light entering direction of the optical lens (1), the third free-form surface (S3) is symmetrical about a first symmetry axis (34), and the first symmetry axis (34) is arranged at an angle with the moving direction of the third lens (33).

8. The optical lens according to any one of claims 5-7, characterized in that, The third lens (33) is located on the side of the first lens (31) away from the second lens (32); or, The third lens (33) is located between the first lens (31) and the second lens (32); or, The third lens (33) is located on the side of the second lens (32) away from the first lens (31).

9. The optical lens according to any one of claims 5 to 8, characterized in that, The combined focal length of the first lens (31) and the second lens (32) is F1, the focal length of the second mirror group (30) is F2, and |F1|>2|F2|.

10. The optical lens according to any one of claims 1 to 9, characterized in that, The first mirror group (10) includes a fourth lens (11) having a fourth free-form surface (S4).

11. The optical lens of claim 10, wherein, The fourth free-form surface (S4) is symmetrical about a second symmetry axis (35), the first mirror group (10) further includes a fifth lens (12) having a fifth free-form surface (S5), the fifth free-form surface (S5) is symmetrical about a third symmetry axis (36), and the straight line direction of the second symmetry axis (35) and the straight line direction of the third symmetry axis (36) are arranged at an angle.

12. The optical lens of any of claims 1-11, wherein, The second mirror group (30) has negative focal power.

13. The optical lens of claim 12, wherein, In the long-focus shooting mode, the focal length of the second lens group (30) is F3, and in the macro shooting mode, the focal length of the second lens group (30) is F4, and the optical lens (1) satisfies the following relationship: |F3|<|F4|.

14. The optical lens of any of claims 1-13, wherein, The focal length of the first lens group (10) is F5, the focal length of the optical lens (1) is F6, and the optical lens (1) satisfies the following relationship: 0.2≤F5 / F6≤5.

15. The optical lens of any of claims 1-14, wherein, The maximum optical effective region (P1) size of the second lens group (30) is D, and the optical lens (1) satisfies the following relationship: D / IMH≤1.

16. The optical lens of any of claims 1-15, wherein, The optical lens (1) further comprises a second prism (40), the second prism (40) is located on the image side of the second lens group (30), and the second prism (40) is used for reflecting light from the second lens group (30).

17. The optical lens of claim 16, wherein, The first prism (20) comprises a first side (21), a second side (22) and a third side (23), the included angle between the first side (21) and the second side (22) is less than 45°, and the light from the first lens group (10) is incident from the first side (21), then reflected from the second side (22) and the first side (21) in turn and emitted from the third side (23).

18. The optical lens of claim 17, wherein, The second prism (40) comprises a fourth side (41), a fifth side (42) and a sixth side (43), the included angle between the fifth side (42) and the sixth side (43) is less than 45°, and the light from the second lens group (30) is incident from the fourth side (41), then reflected from the fifth side (42) and the fourth side (41) in turn and emitted from the sixth side (43).

19. An image capture module comprising an image sensor (60), characterised in that, Further comprising the optical lens (1) according to any one of claims 1 to 18, the optical lens (1) is used for imaging the scene on the object side on the image sensor (60).

20. An electronic device comprising an image processor, characterized in that Further comprising the camera module (300) according to claim 19, the camera module (300) is used for acquiring image data and inputting the image data into the image processor, and the image processor is used for processing the image data.

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