Optical lenses, imaging modules and electronic devices

Abstract

An optical lens (L0), an imaging module (30), and an electronic device, which belong to the technical field of optical imaging, include a first lens (L1) having positive refractive power, from the object side to the image side along an optical axis, the first lens (L1) having a convex surface (L1S1) facing the object side of the first lens (L1) and a convex surface (L1S2) facing the image side of the first lens (L1); and a second lens (L2) having negative refractive power, the second The optical lens (L0) includes a second lens (L2) having a convex surface (L2S1) facing the object side and a concave surface (L2S2) facing the image side of the second lens (L2), and a third lens (L3) having negative refractive power, wherein a concave surface (L3S1) facing the object side of the third lens (L3) and a convex surface (L3S2) facing the image side of the third lens (L3), and the effective focal length of the optical lens (L0) is f, where f is greater than 20 mm.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to Chinese Patent Application No. 202110074970.6 filed in China on January 20, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of optical imaging, in particular to optical lenses, imaging modules and electronic devices. [Background technology]

[0003] At present, with the continuous advancement of smart terminal technology, the photographing function of a smartphone or the like has become indispensable, and the user's demands for photographing quality are also increasing. Therefore, the demands for cameras are also increasing, and the demands for image quality, focusing speed, and zoom magnification are also increasing.

[0004] Currently, the pixels of the main camera of a smart terminal can reach 50 million pixels or more, exceeding those of some SLR cameras, but there is a big difference from SLR cameras in terms of telephoto end and high-magnification zoom lenses. The current smartphone camera arrangement is generally a combination of one main camera with an equivalent focal length of about 24mm to 25mm, one ultra-wide-angle camera with an equivalent focal length of about 16mm to 18mm, and one long focal length lens with an equivalent focal length of 50mm to 130mm. The optical zoom magnification of the camera arranged as above is up to 5.2x, which is obviously insufficient when a higher magnification and longer distance shooting scenario is required. Summary of the Invention [Problem to be solved by the invention]

[0005] The present application proposes an optical lens, an imaging module and an electronic device that can provide a small, high-magnification lens for a mobile terminal, improve the zoom magnification, and meet the lens magnification demand in longer shooting scenarios.

Means for Solving the Problem

[0006] To achieve the above object, the present application adopts the following solutions.

[0007] According to a first aspect, an embodiment of the present application provides an optical lens, which, along the optical axis, from the object side to the image side, is a first lens having a positive refractive power, wherein the surface facing the object side of the first lens is convex, and the surface facing the image side of the first lens is convex; is a second lens having a negative refractive power, wherein the surface facing the object side of the second lens is convex, and the surface facing the image side of the second lens is concave; is a third lens having a negative refractive power, wherein the surface facing the object side of the third lens is concave, and the surface facing the image side of the third lens is convex, and the Abbe numbers of the first lens, the second lens, and the third lens are V1, V2, and V3, respectively, 3.4 < V1 / V2 < 3.9 and 0.45 < V2 / V3 < 0.55 are satisfied, the effective focal length of the optical lens is f, and f > 20 mm.

[0008] According to a second aspect, an embodiment of the present application provides an imaging module, which includes the optical lens described in the first aspect and an image sensor installed on the image side of the optical lens.

[0009] According to a third aspect, an embodiment of the present application provides an electronic device, which includes the imaging module described in the second aspect.

Advantages of the Invention

[0010] The beneficial effects of the technical solutions according to the embodiments of the present application include at least the following: an optical lens is provided, the optical lens including, along an optical axis from an object side to an image side, a first lens having positive refractive power, the surface of the first lens facing the object side being convex, and the surface of the first lens facing the image side being convex, a second lens having negative refractive power, the surface of the second lens facing the object side being convex, and the surface of the second lens facing the image side being concave, and a third lens having negative refractive power, the surface of the third lens facing the object side being concave, and the surface of the third lens facing the image side being convex, the effective focal length of the optical lens is f, where f>20mm, and when an imaging module made of the optical lens is combined with a small image sensor, an equivalent focal length of 200mm or more can be reached, and a zoom magnification of 10x can be reached, which can meet the long focal length demands of a shooting scenario in which an electronic device, such as a mobile terminal, equipped with the imaging module according to the embodiments of the present application is farther away. [Brief description of the drawings]

[0011] [Figure 1] 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application. [Diagram 2] 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application. [Diagram 3] FIG. 2 is a structural schematic diagram of an imaging module according to an embodiment of the present application. [Figure 4] 2 is an optical distortion curve of an optical lens according to an embodiment of the present application. [Diagram 5] 2 is a relative illuminance curve of an optical lens according to an embodiment of the present application. [Figure 6] 1 is an axial chromatic aberration curve of an optical lens according to an embodiment of the present application. [Figure 7] 2 is a field curvature curve of an optical lens according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following clearly and completely describes the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application.

[0013] The terms "first," "second," etc. in the specification and claims of this application are intended to distinguish between similar objects and are not intended to describe a particular order or sequence. It is to be understood that the data so used may be interchanged where appropriate, such that the embodiments of this application may be performed in an order other than that shown or described herein. Note that "and / or" in the specification and claims indicates at least one of the objects connected, and the character " / " generally indicates that the related objects are in an "or" relationship.

[0014] Hereinafter, the optical lens, imaging module and electronic device according to the embodiments of the present application will be described in detail with reference to specific embodiments and application scenarios thereof in conjunction with the drawings.

[0015] FIG. 1 is a structural schematic diagram of an optical lens according to an embodiment of the present application, which has the following components along an optical axis from an object side to an image side: a first lens L1 having a positive refractive power, the surface of the first lens L1 facing an object side being convex, and the surface of the first lens L1 facing an image side being convex; a second lens L2 having a negative refractive power, the surface of the second lens L2 facing the object side being convex and the surface of the second lens L2 facing the image side being concave; a third lens L3 having a negative refractive power, the surface of the third lens L3 facing the object side being concave and the surface of the third lens L3 facing the image side being convex; the Abbe numbers of the first lens, the second lens and the third lens are V1, V2 and V3, respectively; 3.4 < V1 / V2 < 3.9 and 0.45 < V2 / V3 < 0.55 are satisfied, The effective focal length of the optical lens L0 is f, and f > 20 mm.

[0016] Exemplarily, the optical lens L0 shown in FIG. 1 includes a first lens L1, a second lens L2, and a third lens L3 from the object side to the image side along the optical axis. Here, the first lens L1 is a biconvex lens, and the two surfaces of L1 are convex toward the object side and the image side along the center of the optical axis, respectively. The second lens L2 is a convex-concave lens, the surface of L2 facing the object side is convex toward the object side along the center of the optical axis, and the surface of L2 facing the image side is concave along the center of the optical axis. The third lens L3 is a concave-convex lens, the surface of L3 facing the object side is concave toward the object side along the center of the optical axis, and the surface of L3 facing the image side is convex toward the image side along the center of the optical axis.

[0017] Specifically, the lower the Abbe number, the worse the dispersion control. To ensure the color performance of the optical lens, the Abbe numbers of the first lens, the second lens, and the third lens are V1, V2, and V3, respectively, and it is required to satisfy the following proportional requirements.

[0018] 3.4 < V1 / V2 < 3.9 and 0.45 < V2 / V3 < 0.55.

[0019] In addition, generally, there is a relationship between the Abbe number and the refractive index of the lens that the higher the Abbe number, the better the dispersion control, and the lower the refractive index of the corresponding material.

[0020] Specifically, the effective focal length of the optical lens L0 is f, where f>20 mm, and the combined focal length of the optical lens L0, the first lens L1, the second lens L2, and the third lens L3 shown in FIG. 1 is greater than 20 mm. When the optical lens is applied to an electronic device, such as a mobile terminal, it can be combined with a small image sensor to achieve an equivalent focal length of 200 mm or more and a zoom magnification of 10x, and the viewing angle can be optimized. Here, the small image sensor is, for example, a Complementary Metal Oxide Semiconductor (CMOS) or Charge Coupled Device (CCD) photosensitive sensor with an effective imaging size of a diagonal length of 3.8 mm to 4.4 mm.

[0021] Specifically, the effective focal length referred to in this application means the effective focal length (EFL), ie, the actual focal length of this optical lens or lenses.

[0022] The equivalent focal length refers to the focal length of a 35mm camera lens that corresponds to the actual focal length of the lens when the diagonal length of the chip image area of ​​the camera photoelectric sensor (imaging sensor) is equivalent to the diagonal length (42.27 mm) of the size of a 35mm camera.

[0023] Equivalent focal length = effective focal length x lens conversion factor, Lens conversion factor = 43.3 mm (diagonal length of the imaging area of ​​the full-frame camera sensor) ÷ (diagonal length of the imaging area of ​​the image sensor), In general, the smaller the sensor size (the smaller the diagonal length of the imaging area), the higher the lens conversion factor. For example, if the lens conversion factor of a full-frame camera sensor is 1, the equivalent focal length of an optical lens with f=20mm in this full-frame camera is also 20mm. For example, a 1 / 2.7-inch image sensor has a diagonal of about 6.64 mm, a lens conversion factor of about 6.5, and when combined with an optical lens with f = 20 mm, the equivalent focal length is about 130 mm. Therefore, the optical lens according to the present application can reach an equivalent focal length of 200 mm or more when combined with a small sensor. For example, a 1 / 4-inch image sensor with a diagonal of about 4 mm can be used to reach a lens conversion factor of 10.82, and a 1 / 3-inch image sensor with a diagonal of about 3 mm can be used to reach a lens conversion factor of 14.42.

[0024] And because the size of the sensor is small, the imaging module composed of this optical lens and a small sensor can be mounted on electronic devices such as mobile phones and tablet computers, meeting the user's demand for using a long focal length.

[0025] Optionally, the refractive indices of the first lens L1, the second lens L2, and the third lens L3 are N1, N2, and N3 respectively. It satisfies N1 < N3 < N2.

[0026] Specifically, the first lens L1 uses a material with a relatively low refractive index, such as glass. Lenses manufactured with materials with a relatively low refractive index can generally obtain better dispersion control. The second lens L2 and the third lens L3 can each use plastic (resin) lenses with a relatively high refractive index and be combined with plastic (resin) lenses with a relatively low refractive index, which can reduce costs and at the same time not impair the dispersion performance of the optical lens L0.

[0027] Specifically, make the refractive index N1 of the first lens L1 smaller than the refractive index N3 of the third lens L3, and make the refractive index N3 of the third lens L3 smaller than the refractive index N2 of the second lens L2.

[0028] Referring to FIG. 2, L1, L2, L3 and their respective surfaces are labeled. The surface L1S1 of the first lens L1 facing the object side is a spherical surface with a radius of curvature R1 and a radius of curvature of 0 mm. <R1<10mmである。

[0029] Specifically, the above-mentioned L1S1 is a convex surface, which can effectively prevent ghost-like stray light from occurring in the long focal length lens, and uses a low refractive index glass lens to effectively suppress dispersion.

[0030] Optionally, the surface L1S2 of the first lens L1 facing the image side is spherical, the radius of curvature is R2, and the radius of curvature is −28 mm. <R2<-10mmであり、 The surface L2S1 of the second lens L2 facing the object side is aspheric and has a radius of curvature R3 of 20 mm. <R3<50mmである。

[0031] Specifically, the combination of L1S2 and L2S1 can reduce the light incidence angle to avoid stray light.

[0032] Optionally, the surface L2S2 of the second lens L2 facing the image side is aspheric, the radius of curvature is R4, and the radius of curvature is less than 10 mm. <R4<25mmである。

[0033] Specifically, the curved surface of L2S2 is flat, which can reduce spherical aberration.

[0034] Optionally, the surface L3S1 of the third lens L3 facing the object side is aspheric, the radius of curvature is R5, and the maximum curvature is less than −10 mm. <R5<-1mmであり、 The surface L3S2 of the third lens L3 facing the image side is aspheric and has a radius of curvature R6 of −13 mm. <R6<-2mmである。

[0035] Specifically, when the combination of R5 and R6 is a lens with negative refractive power, the optical lens according to the embodiments of the present application can be controlled to achieve a high modulation transfer function (MTF) effect with curvature of field and aberration when using an image sensor with a diagonal length of 3.8 mm to 4.4 mm.

[0036] Optionally, the effective focal lengths of the first lens L1, the second lens L2, and the third lens L3 are f1, f2, and f3 respectively, 8.0 mm < f1 < 15 mm, -80 mm < f2 < -40 mm, -30 mm < f3 < -15 mm are satisfied.

[0037] Specifically, after combining L1, L2, and L3, the effective focal length f of the optical lens L0 can be made > 20 mm.

[0038] Optionally, the central thicknesses of the first lens, the second lens, and the third lens are CT1, CT2, and CT3 respectively, 1 mm < CT1 < 3 mm, 1 mm < CT2 < 4 mm, 1 mm < CT3 < 4 mm are satisfied.

[0039] Specifically, due to the thin central thickness, the optical lens according to the embodiments of the present application can be made more compact and is easy to be mounted on a mobile terminal, such as a mobile phone or a tablet computer.

[0040] Optionally, the optical lens further includes a diaphragm disposed between the first lens and the second lens.

[0041] Specifically, the position of the diaphragm L6 is located between L1 and L2. Referring to FIG. 3, by disposing the diaphragm L6 between L1 and L2, the aberration and relatively good manufacturing sensitivity can be effectively controlled.

[0042] Optionally, referring to FIG. 2, the optical lens further includes an infrared filter L4 installed on the image side of the third lens L3.

[0043] Optionally, referring to FIG. 2, the optical lens is installed on the image side of the third lens L3 and further includes a prism L5 for changing the direction of light rays.

[0044] Specifically, referring to FIG. 3, an infrared filter L4 and a prism L5 are sequentially provided on the image side of the third lens L3. By installing the prism L5, the imaging sensor C1 can be mounted above the lenses L1 - L3, and L4, L5, so that it is not necessary to mount C1 on the image side of the optical lens along the optical axis. Thereby, the volume of the optical lens is reduced, and more space is saved when it is mounted on an electronic device.

[0045] Specifically, the optical lens and the image sensor according to the embodiments of the present application can constitute an imaging module. When applied to an electronic device (such as a mobile phone, a tablet computer, etc.), it can be used in combination with an image sensor (photosensitive element, such as a CDD, CMOS, etc.) with a diagonal length of the effective imaging size of 3.8 mm to 4.4 mm, and is suitable for visible light with a wavelength range of 400 nm to 700 nm.

[0046] Specifically, referring to FIGS. 4 - 7, they are the performance parameters of the optical lens according to the embodiments of the present application.

[0047] Specifically, the effective focal length EFL of the optical lens L0 satisfies 24 mm < EFL < 25 mm, the aperture value is F3.5, the diagonal field of view (DFOV) = 9.4°, the equivalent focal length can reach 250 mm, the zoom ratio can reach 10x, and the DFOV is optimized within 10 degrees.

[0048] FIG. 4 shows the optical distortion, where - 1% < optical distortion < 1%. FIG. 5 shows the relative illumination, where the relative illumination is >95%. FIG. 6 shows axial chromatic aberration for light rays with wavelengths of 470 nm, 550 nm, and 650 nm, respectively. FIG. 7 shows the field curvature, and shows the sagittal and tangential field curvatures, respectively.

[0049] Specifically, the two surfaces L2 and L3 are both aspheric, and the aspheric coefficients are obtained according to the aspheric equation.

[0050] The aspheric equation is:

[0051] JPEG0007606621000001.jpg14150 Here, the parameters are: z: position of the aspheric surface Z axis, c: reciprocal of radius of curvature, r: position of the aspheric R axis, k: conic coefficient, α i : aspheric coefficient, ρ: The position of the equivalent aspheric surface R axis.

[0052] [Table 1] Optical lens parameter comparison table (unit: mm) JPEG0007606621000002.jpg87170 The aspherical coefficients A, B, and C are coefficient values ​​when the orders of the aspherical terms are i=1, i=2, and i=3, respectively.

[0053] In summary, when an imaging module including an optical lens according to an embodiment of the present application is combined with an imaging module including a small image sensor and installed in an electronic device, an equivalent focal length of 200 mm or more can be achieved, and a zoom magnification of 10x can be achieved. An electronic device, such as a mobile terminal, equipped with an imaging module according to an embodiment of the present application can meet the demand for long focal lengths in longer shooting scenarios.

[0054] Referring to FIG. 3, an embodiment of the present application provides an imaging module 30, which includes an optical lens L0 described in any one of the embodiments of the present application, and an image sensor C1 installed on the image side of the optical lens L0.

[0055] Specifically, an optical signal is transmitted to the image sensor C1 by the optical lens L0, and the image sensor C1 converts the optical signal into an electrical signal corresponding to an image optical signal and transmits it to an electronic device in which the imaging module 30 is mounted.

[0056] Specifically, the effective imaging size of the image sensor C1 is a diagonal length of 3.8 mm to 4.4 mm.

[0057] Specifically, the combination of the image sensor C1 and the optical lens L0 realizes a zoom magnification of 10x and an equivalent focal length of 200mm or more, thereby satisfying the demand for long focal lengths.

[0058] An embodiment of the present application further provides an electronic device, which includes an imaging module according to an embodiment of the present application. The electronic device further includes a display module such as a display screen, and a user can take a picture by viewing the viewing effect through the display module such as the screen of the electronic device.

[0059] The electronic device in the embodiment of the present application may be a mobile electronic device or a non-mobile electronic device. For example, the mobile electronic device may be a mobile phone, a tablet computer, a notebook computer, a palmtop computer, an in-vehicle electronic device, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a personal digital assistant (PDA), and the non-mobile electronic device may be a personal computer (PC), a television (TV), a deposit and payment machine, or a self-service machine, and the embodiment of the present application is not specifically limited.

[0060] The electronic device in the embodiment of the present application may be a device having an operating system, which may be an Android operating system, an ios operating system, or other possible operating systems, and the embodiment of the present application is not specifically limited.

[0061] The electronic device according to the embodiment of the present application can be equipped with the optical lenses of Figures 1 to 7 and the imaging module of Figure 3, thereby achieving a zoom magnification of 10x and an equivalent focal length of 200 mm or more, thereby meeting the demand for long focal length use.

[0062] It should be explained that in this specification, the terms "comprise", "include", "includes" or any other variants thereof are intended to cover the non-exclusive "comprise", whereby a process, method, article or apparatus that includes a set of elements includes not only those elements, but also other elements not expressly listed or inherent to such process, method, article or apparatus. Absent any further limitations, an element limited by the phrase "comprises one or more" does not preclude the presence of other identical elements in the process, method, article or apparatus that includes the element. It should be pointed out that the scope of the method and apparatus in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may include performing functions in an essentially simultaneous manner or in the reverse order based on the functions involved, for example, the described method can be performed in a different order than described, and various steps can be added, omitted or combined. Also, features described with reference to some examples can be combined in other examples.

[0063] From the above description of the embodiments, it is clear to those skilled in the art that the methods of the above embodiments can be realized in the form of software and a necessary general-purpose hardware platform. Of course, they can also be realized in hardware, but in many cases the former is a more preferred embodiment. Based on this understanding, the technical solution of the present application may be substantially or in part embodied in the form of a software product. The computer software product is stored in a storage medium (e.g., a Read-Only Memory (ROM) / Random Access Memory (RAM), a magnetic disk, an optical disk) and includes some instructions for causing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in the embodiments of the present application.

[0064] The above describes the embodiments of the present application in conjunction with the drawings, but the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not limiting. Those skilled in the art can take the suggestions of this application and make many forms without departing from the spirit and scope of the claims of this application, all of which belong to the protection scope of this application.

Claims

1. An optical lens, comprising: a first lens having a positive refractive power, the first lens having a convex surface facing an object side and a convex surface facing an image side; a second lens having negative refractive power, the surface of the second lens facing the object side being convex and the surface of the second lens facing the image side being concave; a third lens having negative refractive power, the surface of the third lens facing the object side being concave and the surface of the third lens facing the image side being convex, the Abbe numbers of the first lens, the second lens, and the third lens are V1, V2, and V3, respectively; 3.4<V1 / V2<3.9 and 0.45<V2 / V3<0.55 are satisfied, The optical lens has an effective focal length, f, where f>20 mm.

2. 2. The optical lens according to claim 1, wherein the surface of the first lens facing the object side is spherical, has a radius of curvature R1, and satisfies 0 mm<R1<10 mm.

3. the surface of the first lens facing the image side is a spherical surface, the radius of curvature is R2, and −28 mm<R2<−10 mm; 2. The optical lens according to claim 1, wherein the surface of the second lens facing the object side is aspheric, has a radius of curvature R3, and satisfies 20 mm<R3<50 mm.

4. 2. The optical lens according to claim 1, wherein the surface of the second lens facing the image side is aspheric, has a radius of curvature R4, and is in the range of 10 mm<R4<25 mm.

5. the surface of the third lens facing the object side is aspheric, the radius of curvature is R5, and −10 mm<R5<−1 mm; 2. The optical lens according to claim 1, wherein the surface of the third lens facing the image side is aspheric, has a radius of curvature R6, and is in the range of −13 mm<R6<−2 mm.

6. the effective focal lengths of the first lens, the second lens, and the third lens are f1, f2, and f3, respectively; 8.0mm<f1<15mm, -80mm<f2<-40mm, 2. The optical lens according to claim 1, wherein −30 mm<f3<−15 mm is satisfied.

7. The center thicknesses of the first lens, the second lens, and the third lens are CT1, CT2, and CT3, respectively; 1mm<CT1<3mm, 1mm<CT2<4mm, The optical lens according to claim 1 , wherein 1 mm<CT3<4 mm is satisfied.

8. The optical lens of claim 1 , further comprising an aperture located between the first lens and the second lens.

9. The optical lens of claim 1 , further comprising an infrared filter located on the image side of the third lens.

10. The optical lens of claim 1 , further comprising a prism disposed on the image side of the third lens for redirecting light rays.

11. 11. An imaging module comprising: an optical lens according to claim 1; and an image sensor disposed on an image side of the optical lens.

12. An electronic device comprising the imaging module according to claim 11.

Images