Optical imaging lens

Abstract

The application provides an optical imaging lens, which comprises a first lens, a second lens, a third lens and a fourth lens in sequence from an object side to an image side along an optical axis, the first lens has a positive focal length; the second lens has a negative focal length, and a curvature radius of an object side surface thereof is positive; the third lens has a positive focal length; the fourth lens has a negative focal length; at least one spacer is arranged between any two adjacent lenses of the first lens to the fourth lens and between the fourth lens and the image side, wherein the spacer in contact with the image side of the first lens is a first spacer, the spacer in contact with the image side of the second lens is a second spacer, the spacer in contact with the image side of the third lens is a third spacer, and the spacer in direct contact with the image side of the fourth lens is a fourth spacer; the optical imaging lens satisfies 20.0 < CP2*D3s / (T23*CP3) < 50.0.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical elements, in particular, to an optical imaging lens. BACKGROUND

[0002] With the popularization of face recognition technology, users have higher and higher requirements for infrared lenses. At present, the optical design of mainstream infrared lenses on the market mostly only considers the cooperation of optical imaging lenses, ignoring the influence of assembly structure on the performance of the lens, especially the arrangement of spacers between structures. How to design an infrared lens that takes into account high imaging quality, easy assembly and controllable cost has become a difficult problem to be solved. SUMMARY

[0003] The present application provides an optical imaging lens, which comprises a first lens, a second lens, a third lens and a fourth lens in order from the object side to the image side along the optical axis, the first lens has a positive focal length; the second lens has a negative focal length, the curvature radius of the object side surface thereof is negative; the third lens has a positive focal length; the fourth lens has a negative focal length; at least one spacer is arranged between any two adjacent lenses of the first lens to the fourth lens and between the fourth lens and the image side, wherein the spacer in contact with the image side surface of the first lens is a first spacer, the spacer in contact with the image side surface of the second lens is a second spacer, the spacer in contact with the image side surface of the third lens is a third spacer, and the spacer in direct contact with the image side surface of the fourth lens is a fourth spacer; the optical imaging lens satisfies: 20.0 D3s / (T23 CP3)<50.0, wherein CP2 is the maximum thickness of the second spacer, CP3 is the maximum thickness of the third spacer, D3s is the outer diameter of the object side surface of the third spacer, and T23 is the interval distance of the second lens and the third lens along the optical axis.

[0004] In one embodiment, the optical imaging lens satisfies: -11.0≤(R3 D2m) / (R2 D1m)≥<-2.0, wherein R2 is the curvature radius of the image side surface of the first lens, R3 is the curvature radius of the object side surface of the second lens, D1m is the outer diameter of the image side surface of the first spacer, and D2m is the outer diameter of the image side surface of the second spacer.

[0005] In one embodiment, the optical imaging lens satisfies: 40.0<EP12 f1 / (R1 CP1) < 55.0, wherein CP1 is the maximum thickness of the first spacer, EP12 is the interval between the first spacer and the second spacer, f1 is the effective focal length of the first lens, and R1 is the curvature radius of the object side surface of the first lens.

[0006] In one embodiment, the optical imaging lens satisfies: 20.0 < R2 d1s / (CT1 R1-T12 R1) < 50.0, wherein R2 is the curvature radius of the image side surface of the first lens, d1s is the inner diameter of the object side surface of the first spacer, CT1 is the central thickness of the first lens on the optical axis, T12 is the interval distance of the first lens and the second lens on the optical axis, and R1 is the curvature radius of the object side surface of the first lens.

[0007] In one embodiment, the optical imaging lens satisfies: -12.0 < (R4 D2s) / (R5 D3s) < -3.0, wherein R4 is the curvature radius of the image side surface of the second lens, R5 is the curvature radius of the object side surface of the third lens, D2s is the outer diameter of the object side surface of the second spacer, and D3s is the outer diameter of the object side surface of the third spacer.

[0008] In one embodiment, the optical imaging lens satisfies: 11.0 < R7 / CP3 + (R6 / T34) < 28.0, wherein R6 is the curvature radius of the image side surface of the third lens, R7 is the curvature radius of the object side surface of the fourth lens, T34 is the interval distance of the third lens and the fourth lens on the optical axis, and CP3 is the maximum thickness of the third spacer.

[0009] In one embodiment, the optical imaging lens satisfies: 1.0 < (TD-d2s) / T23 < 6.0, wherein TD is the axial distance from the object side surface of the first lens to the image side surface of the fourth lens, T23 is the interval distance of the second lens and the third lens on the optical axis, and d2s is the inner diameter of the object side surface of the second spacer.

[0010] In one embodiment, the optical imaging lens satisfies: 5.0 < (TD-d1m) / (CT1-CT2) < 8.0, wherein TD is the axial distance from the object side surface of the first lens to the image side surface of the fourth lens, CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and d1m is the inner diameter of the image side surface of the first spacer.

[0011] In one embodiment, the optical imaging lens satisfies: -12.0 < f2 / d2m < 5.0, where f2 is the effective focal length of the second lens and d2m is the inner diameter of the image side of the second spacer.

[0012] In one embodiment, the optical imaging lens satisfies: 1.0 < T12 / T23 < 8.0, where T12 is the distance between the first lens and the second lens on the optical axis, and T23 is the distance between the second lens and the third lens on the optical axis.

[0013] In one embodiment, the optical imaging lens satisfies: 10.0 < f1 / T12 < 15.0, where f1 is the effective focal length of the first lens and T12 is the distance between the first lens and the second lens on the optical axis.

[0014] This application provides a four-element lens architecture. By rationally configuring the focal length of each lens, the number of spacers between each lens, the maximum thickness of the second and third spacers, the outer diameter of the object side of the third spacer, and the spacing between the second and third lenses on the optical axis, the overall light deflection angle can be effectively controlled while meeting the lens imaging requirements. This helps to balance the aberrations of the entire system and effectively reduces the sensitivity of the second and third lenses, enhancing their resistance to changes under harsh environmental conditions and thus further improving their quality. Attached Figure Description

[0015] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0016] Figure 1 A schematic diagram illustrating the elimination of stray light by an optical imaging lens according to Embodiments 1 to 3 of this application is shown;

[0017] Figures 2 to 4 A schematic diagram of the structure of an optical imaging lens according to Embodiment 1 of this application is shown;

[0018] Figures 5A to 5D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging lens of Example 1 are shown respectively.

[0019] Figures 6 to 7 A schematic diagram of the structure of an optical imaging lens according to Embodiment 2 of this application is shown;

[0020] Figures 8A to 8D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging lens of Example 2 are shown respectively.

[0021] Figures 9 to 10A schematic diagram of the structure of an optical imaging lens according to Embodiment 3 of this application is shown; and

[0022] Figures 11A to 11D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging lens of Example 3 are shown respectively. Detailed Implementation

[0023] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0025] The imaging lens group, lens barrel structure and spacer element in the various embodiments of this application can be arbitrarily combined, and are not limited to the imaging lens group in one embodiment being combined only with the lens barrel structure and spacer element of that embodiment.

[0026] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0027] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0028] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0029] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] The features, principles and other aspects of this application are described in detail below.

[0032] An optical imaging lens according to an exemplary embodiment of this application may include four lenses with focal lengths, namely a first lens, a second lens, a third lens, and a fourth lens. These four lenses are arranged sequentially along the optical axis from the object side to the image side. Any two adjacent lenses among the first to fourth lenses may have a spacing distance.

[0033] In an exemplary embodiment, the first lens may have a negative focal length; the second lens has a negative focal length and a negative radius of curvature on its object-side surface; the third lens has a positive focal length; and the fourth lens has a negative focal length. At least one spacer is provided between any two adjacent lenses from the first lens to the fourth lens, and between the fourth lens and its image side. The spacer in contact with the image side of the first lens is the first spacer, the spacer in contact with the image side of the second lens is the second spacer, the spacer in contact with the image side of the third lens is the third spacer, and the spacer in contact with the image side of the fourth lens is the fourth spacer. By appropriately setting the focal lengths of the first lens to the fourth lens, the overall light refraction angle can be effectively controlled, and the aberrations of the entire system can be balanced.

[0034] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 20.0 < CP2. D3s / (T23 CP3) < 50.0, where CP2 is the maximum thickness of the second spacer, CP3 is the maximum thickness of the third spacer, D3s is the outer diameter of the object-side surface of the third spacer, and T23 is the distance between the second and third lenses on the optical axis. Reasonably controlling the distance between the second and third lenses on the optical axis helps achieve a compact lens structure and corrects off-axis aberrations, improving image quality. By reasonably controlling the maximum thickness of the second and third spacers, the outer diameter of the object-side surface of the third spacer, and the distance between the second and third lenses on the optical axis, the sensitivity of the second and third lenses can be effectively reduced, enhancing their resistance to changes under harsh environmental conditions and further improving their quality. More specifically, the ratio of the product of CP2 and D3s to the product of T23 and CP3 can further satisfy: 23.0 < CP2. D3s / (T23 CP3) < 35.0.

[0035] In an exemplary embodiment, the optical imaging lens according to this application satisfies: -11.0 ≤ (R3 D2m) / (R2 D1m < -2.0, R2 is the radius of curvature of the image side of the first lens, R3 is the radius of curvature of the object side of the second lens, D1m is the outer diameter of the image side of the first spacer, and D2m is the outer diameter of the image side of the second spacer. By reasonably setting the dimensions of the radius of curvature of the image side of the first lens, the radius of curvature of the object side of the second lens, the outer diameter of the first spacer, and the outer diameter of the second spacer, the reflected light path through the object side of the second lens and the light passing through this position to the next lens can be minimized, reducing stray light and ghosting, and giving the optical imaging lens a strong ability to balance astigmatism. Reasonably controlling the deflection angle of the principal ray also helps the optical imaging lens recognize more information. More specifically, the product of R3 and D2m and the product of R2 and D1m can further satisfy: -6.0 ≤ (R3m / D2m) D2m) / (R2 D1m) < -2.0.

[0036] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 40.0 < EP12 f1 / (R1 CP1) < 55.0, where CP1 is the maximum thickness of the first spacer, EP12 is the spacing between the first and second spacers, f1 is the effective focal length of the first lens, and R1 is the radius of curvature of the object-side surface of the first lens. By controlling the radius of curvature R1 of the object-side surface of the first lens and constraining the optical power of the first lens within a certain range, it is convenient to correct meridional astigmatism and off-axis coma. Furthermore, by controlling the thickness of the first spacer and the spacing between the first and second spacers, assembly stability is ensured. More specifically, the product of EP12 and f1 and the product of R1 and CP1 can further satisfy: 43.0 < EP12. f1 / (R1 CP1) < 53.0.

[0037] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 20.0 < R2 d1s / (CT1 R1-T12 R1)≤50.0, R2 is the radius of curvature of the image-side surface of the first lens, d1s is the inner diameter of the object-side surface of the first spacer, CT1 is the center thickness of the first lens on the optical axis, T12 is the spacing between the first and second lenses on the optical axis, and R1 is the radius of curvature of the object-side surface of the first lens. By controlling the values ​​of the radius of curvature R2 of the image-side surface of the first lens, the inner diameter d1s of the object-side surface of the first spacer, the spacing T12 of the first and second lenses on the optical axis, the center thickness CT1 of the first lens on the optical axis, and the radius of curvature R1 of the object-side surface of the first lens within a reasonable range, the distortion contribution of each field of view of the system can be effectively controlled, and the system distortion can be kept within 3%. By configuring the inner diameter parameter of the first spacer, stray light between the first and second lenses can also be effectively improved. More specifically, R2, d1s, CT1, T12, and R1 can further satisfy: 20.0<2R2 d1s / (CT1 R1-T12 R1)≤46.0.

[0038] In an exemplary embodiment, the optical imaging lens according to this application satisfies: -12.0 ≤ (R4 D2s) / (R5 Where D3s) < -3.0, R4 is the radius of curvature of the image-side surface of the second lens, R5 is the radius of curvature of the object-side surface of the third lens, D2s is the outer diameter of the object-side surface of the second spacer, and D3s is the outer diameter of the object-side surface of the third spacer. Controlling the radius of curvature R4 of the image-side surface of the second lens, R5 of the object-side surface of the third lens, and the outer diameters D2s and D3s of the object-side surface of the second and third spacers within a reasonable range can control the total deflection angle of the edge field of view on the two surfaces and effectively reduce the sensitivity of the system. More specifically, the product of R4 and D2s and the product of R5 and D3s can further satisfy: -11.0 ≤ (R4) D2s) / (R5 D3s) < -3.5.

[0039] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 11.0 ≤ R7 / CP3 + (R6 / T34) < 28.0, where R6 is the radius of curvature of the image-side surface of the third lens, R7 is the radius of curvature of the object-side surface of the fourth lens, T34 is the spacing between the third and fourth lenses on the optical axis, and CP3 is the maximum thickness of the third spacer. By reasonably controlling the values ​​of the radius of curvature R6 of the image-side surface of the third lens, the radius of curvature R7 of the object-side surface of the fourth lens, the spacing between the third and fourth lenses on the optical axis T34, and the maximum thickness CP3 of the third spacer, it is beneficial to balance advanced spherical aberration and avoid collisions caused by the third and fourth lenses being too close, thereby improving the lens yield. More specifically, R7, CP3, R6, and T34 can satisfy: 11.0 ≤ R7 / CP3 + (R6 / T34) < 27.5.

[0040] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 1.0 < (TD - d2s) / T23 < 6.0, where TD is the axial distance from the object side of the first lens to the image side of the fourth lens, T23 is the optical axis spacing between the second and third lenses, and d2s is the inner diameter of the object side of the second spacer. By reasonably controlling the axial distance TD from the object side of the first lens to the image side of the fourth lens, the lens can be miniaturized. By controlling the inner diameter d2s of the object side of the second spacer, stray light entering the third lens is reduced. Furthermore, by controlling the optical axis spacing T23 between the second and third lenses, the lens spacing can be avoided from being too small, thereby reducing assembly difficulty. More specifically, the difference between TD and d2s and T23 satisfies: 1.5 < (TD - d2s) / T23 < 5.5.

[0041] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 5.0 < (TD - d1m) / (CT1 - CT2) < 8.0, where TD is the axial distance from the object-side surface of the first lens to the image-side surface of the fourth lens, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and d1m is the inner diameter of the image-side surface of the first spacer. By reasonably controlling the center thicknesses CT1 of the first lens and CT2 of the second lens, the focal length distribution of the optical imaging lens is constrained, and the lens forming process meets the manufacturing requirements while ensuring the total optical length; by controlling the inner diameter d1m of the image-side surface of the first spacer, edge stray light is controlled, ghosting is eliminated, and the lens imaging quality is improved. More specifically, the difference between TD and d1m and the difference between CT1 and CT2 can satisfy: 5.5 < (TD - d1m) / (CT1 - CT2) < 7.1.

[0042] In an exemplary embodiment, the optical imaging lens according to this application satisfies: -12.0 < f2 / d2m < 5.0, where f2 is the effective focal length of the second lens and d2m is the inner diameter of the image-side surface of the second spacer. By reasonably controlling the effective focal length of the second lens and the ratio of f2 to the inner diameter d2m of the image-side surface of the second spacer, it is beneficial to adjust the angles of the incident light and the initial light of the optical system, effectively correct the chromatic aberration of the system, and improve the imaging quality of the optical imaging lens. More specifically, the ratio of f2 to d2m can satisfy: -12.0 < f2 / d2m < -5.0.

[0043] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 1.0 < T12 / T23 < 8.0, where T12 is the distance between the first lens and the second lens on the optical axis, and T23 is the distance between the second lens and the third lens on the optical axis. By reasonably arranging the distance T12 between the first lens and the second lens on the optical axis and the distance T23 between the second lens and the third lens on the optical axis, a compact layout of the first lens and the second lens can be achieved, thereby helping to shorten the overall lens length, ensuring lens miniaturization, and making the optical imaging lens suitable for portable electronic products. More specifically, the ratio of T12 to T23 satisfies: 1.0 < T12 / T23 < 4.0.

[0044] In an exemplary embodiment, the optical imaging lens according to this application satisfies: 10.0 < f1 / T12 < 15.0, where f1 is the effective focal length of the first lens, and T12 is the distance between the first and second lenses on the optical axis. By reasonably controlling the spatial ratio between the effective focal length f1 of the first lens and the distance between the first and second lenses on the optical axis, it is beneficial to ensure the lens assembly process and to achieve miniaturization of the optical imaging lens. More specifically, the ratio of f to T12 satisfies: 12.0 < f1 / T12 < 14.0.

[0045] In an exemplary embodiment, the effective focal length f1 of the first lens may be in the range of 2.0 mm to 4.0 mm, the effective focal length f2 of the second lens may be in the range of -20.0 mm to -9.0 mm, and the axial distance TD between the object side of the first lens and the image side of the fourth lens may be in the range of 1.5 mm to 2.5 mm.

[0046] In an exemplary embodiment, the inner diameter d1m of the image side of the first spacer can be, for example, in the range of 1.0mm to 1.5mm, the inner diameter d1s of the object side of the first spacer can be, for example, in the range of 1.0mm to 1.5mm, the outer diameter D1m of the image side of the first spacer and the outer diameter D2m of the image side of the second spacer can both be, for example, in the range of 2.0mm to 3.0mm, the outer diameter D2s of the object side of the second spacer can be, for example, in the range of 1.5mm to 3.5mm, the inner diameter d2s and the outer diameter d2m of the object side of the second spacer can both be, for example, in the range of 1.5mm to 2.0mm, the outer diameter D3s of the object side of the third spacer can be, for example, in the range of 3.0mm to 4.0mm, the gap EP12 between the first spacer and the second spacer can be, for example, in the range of 0.3mm to 0.5mm, and the maximum thickness CP1 of the first spacer and the maximum thickness CP3 of the third spacer can both be, for example, in the range of 0.02mm to 0.03mm.

[0047] In an exemplary embodiment, the optical imaging lens according to this application further includes an aperture stop disposed between the object side and the first lens. Optionally, the optical imaging lens may also include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging plane. This application proposes an optical imaging lens with characteristics such as small aberrations, high imaging quality, and strong resistance to changes. The optical imaging lens according to the above embodiments of this application can employ multiple lenses, such as the four lenses described above. By rationally allocating the focal length, surface shape, center thickness of each lens, and on-axis spacing between each lens, incident light can be effectively converged, the overall optical length of the imaging lens can be reduced, and the manufacturability of the imaging lens can be improved, making the optical imaging lens more conducive to production and processing.

[0048] In embodiments of this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface; that is, at least one mirror surface from the object-side surface of the first lens to the image-side surface of the fourth lens is an aspherical mirror surface. The characteristic of an aspherical lens is that its curvature changes continuously from the lens center to the lens periphery. Unlike a spherical lens, which has a constant curvature from the lens center to the lens periphery, an aspherical lens has better curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. Optionally, at least one of the object-side and image-side surfaces of each of the first, second, third, and fourth lenses is an aspherical mirror surface. Optionally, both the object-side and image-side surfaces of each of the first, second, third, and fourth lenses are aspherical mirror surfaces.

[0049] However, those skilled in the art will understand that the number of lenses constituting the optical imaging lens can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although four lenses are described as an example in the embodiments, the optical imaging lens is not limited to including four lenses. If desired, the optical imaging lens may also include other numbers of lenses.

[0050] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the optical imaging lens applicable to the above-described embodiments. Figure 1 Schematic diagrams illustrating the elimination of stray light by optical imaging lenses according to Embodiments 1 to 3 of this application are shown. Figure 1 As shown, stray light enters the lens from the object side and exits from the image side. By adjusting the image-side curvature radius of the first lens, the object-side curvature radius of the second lens, the outer diameter of the first spacer, the outer diameter of the second spacer, or any combination thereof, the reflected light path through the object-side position of the second lens and the light rays penetrating to the next lens through that position can be significantly reduced, thereby reducing stray light and ghosting, and enabling the optical imaging lens to have a strong ability to balance astigmatism.

[0051] Example 1

[0052] The following is for reference Figures 2 to 5D This application describes an optical imaging lens according to Embodiment 1. Embodiment 1 includes Embodiment 1-1 and Embodiment 1-2. Figure 2 and Figure 3 A schematic diagram of the structure of an optical imaging lens according to Embodiment 1-1 of this application is shown. Figure 4 A schematic diagram of the structure of an optical imaging lens according to embodiments 1-2 of this application is shown.

[0053] like Figure 3 and Figure 4As shown, the optical imaging lenses in Examples 1-1 and 1-2 include, in order from the object side to the image side: aperture stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter and imaging surface (not shown).

[0054] The first lens E1 has a positive focal length, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has a negative focal length, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has a positive focal length, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has a negative focal length, with its object-side surface S7 being convex and its image-side surface S8 being concave. The filter has an object-side surface S9 and an image-side surface S10. Light from the object passes sequentially through each surface S1 to S10 and is finally imaged on the imaging surface S11.

[0055] Table 1 shows the basic parameters of the optical imaging lens of Example 1-1 / Example 1-2, where the units for radius of curvature, thickness / distance and focal length are millimeters (mm).

[0056]

[0057] Table 1

[0058] In Example 1-1, the inner diameter d1m of the image-side surface of the first spacer P1 of the optical imaging lens is 1.366 mm, the inner diameter d1s of the object-side surface of the first spacer P1 is 1.410 mm, the outer diameter D1m of the image-side surface of the first spacer P1 is 2.200 mm, the outer diameter D2m of the image-side surface of the second spacer P2 and the outer diameter D2s of the object-side surface of the second spacer P2 are both 3.300 mm, the inner diameter d2s of the object-side surface of the second spacer P2 is 1.729 mm, the inner diameter d2m of the image-side surface of the second spacer P2 is 1.685 mm, the outer diameter D3s of the object-side surface of the third spacer P3 is 3.400 mm, the spacing EP12 between the first spacer P1 and the second spacer P2 is 0.465 mm, the maximum thickness CP1 of the first spacer P1 and the maximum thickness CP3 of the third spacer P3 are both 0.022 mm. The axial distance TD from the object-side surface of the first lens E1 to the image-side surface of the fourth lens E4 is 2.06 mm.

[0059] In embodiments 1-2, the inner diameter d1m of the image-side surface of the first spacer P1 of the optical imaging lens is 1.339 mm, the inner diameter d1s of the object-side surface of the first spacer P1 is 1.383 mm, the outer diameter D1m of the image-side surface of the first spacer P1 is 2.200 mm, the outer diameter D2m of the image-side surface of the second spacer P2 and the outer diameter D2s of the object-side surface of the second spacer P2 are both 3.300 mm, the inner diameter d2s of the object-side surface of the second spacer P2 is 1.707 mm, the inner diameter d2m of the image-side surface of the second spacer P2 is 1.663 mm, the outer diameter D3s of the object-side surface of the third spacer P3 is 3.400 mm, the spacing EP12 between the first spacer P1 and the second spacer P2 is 0.465 mm, the maximum thickness CP1 of the first spacer P1 and the maximum thickness CP3 of the third spacer P3 are both 0.022 mm. The axial distance TD from the object-side surface of the first lens E1 to the image-side surface of the fourth lens E4 is 2.06 mm.

[0060] In Examples 1-1 and 1-2, the object-side surface and image-side surface of any one of the first lens E1 to the fourth lens E4 are aspherical, and the surface shape of each aspherical lens is... The following aspherical formulas can be used for limitation:

[0061] (1)

[0062] in, For an aspherical surface along the optical axis at a height of h When the position is such that the distance from the vertex of the non-spherical surface is the sag; c For the paraxial curvature of an aspherical surface, c =1 / R (i.e., paraxial curvature) c (The reciprocal of the radius of curvature R in Table 1 above). k The conic coefficient; Ai Is it an aspherical first i -th order correction coefficients. Table 2 below shows the higher-order coefficients that can be used for each aspherical mirror S1-S8 in Example 1-1 / Example 1-2. A 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0063]

[0064] Table 2

[0065] Figure 5A The on-axis chromatic aberration curves of the optical imaging lenses of Embodiment 1-1 / Embodiment 1-2 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 5B The astigmatism curves of the optical imaging lenses of Embodiment 1-1 / Embodiment 1-2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 5C The distortion curves of the optical imaging lenses of Embodiment 1-1 / Embodiment 1-2 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 5D The magnification chromatic aberration curves of the optical imaging lenses of Embodiment 1-1 / Embodiment 1-2 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to... Figures 5A to 5D It can be seen that the optical imaging lens given in Example 1-1 / Example 1-2 can achieve good imaging quality.

[0066] Example 2

[0067] Example 2 includes Example 2-1 and Example 2-2. Refer to the following... Figures 6 to 8D This paper describes optical imaging lenses according to Embodiments 2-1 and 2-2 of this application. For the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted in this embodiment and the following embodiments. Figure 6 and Figure 7 Schematic diagrams of the optical imaging lenses according to Embodiments 2-1 and 2-2 of this application are shown respectively.

[0068] like Figure 6 and Figure 7 As shown, the optical imaging lenses of Embodiments 2-1 and 2-2 both include, from the object side to the image side, the following components in sequence: aperture stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter, and imaging surface (not shown).

[0069] The first lens E1 has a positive focal length, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has a negative focal length, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has a positive focal length, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has a negative focal length, with its object-side surface S7 being convex and its image-side surface S8 being concave. The filter has an object-side surface S9 and an image-side surface S10. Light from the object passes sequentially through each surface S1 to S10 and is finally imaged on the imaging surface S11.

[0070] In Example 2-1, the inner diameter d1m of the image-side surface of the first spacer P1 of the optical imaging lens is 1.331 mm, the inner diameter d1s of the object-side surface of the first spacer P1 is 1.375 mm, the outer diameter D1m of the image-side surface of the first spacer P1 is 2.240 mm, the outer diameter D2m of the image-side surface of the second spacer P2 and the outer diameter D2s of the object-side surface of the second spacer P2 are both 2.483 mm, the inner diameter d2s of the object-side surface of the second spacer P2 is 1.693 mm, the inner diameter d2m of the image-side surface of the second spacer P2 is 1.649 mm, the outer diameter D3s of the object-side surface of the third spacer P3 is 3.400 mm, the spacing EP12 between the first spacer P1 and the second spacer P2 is 0.400 mm, the maximum thickness CP1 of the first spacer P1 and the maximum thickness CP3 of the third spacer P3 are both 0.022 mm. The axial distance TD from the object-side surface of the first lens E1 to the image-side surface of the fourth lens E4 is 1.99 mm.

[0071] In Example 2-2, the inner diameter d1m of the image side of the first spacer P1 of the optical imaging lens is 1.382mm, the inner diameter d1s of the object side of the first spacer P1 is 1.426mm, the outer diameter D1m of the image side of the first spacer P1 is 2.240mm, the outer diameter D2m of the image side of the second spacer P2 is 3.300mm, the outer diameter D2s of the object side of the second spacer P2 is 1.634mm, the inner diameter d2s of the object side of the second spacer P2 is 1.707mm, the inner diameter d2m of the image side of the second spacer P2 is 1.678mm, the outer diameter D3s of the object side of the third spacer P3 is 3.440mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.400mm, and the maximum thickness CP1 of the first spacer P1 and the maximum thickness CP3 of the third spacer P3 are both 0.022mm. The on-axis distance TD from the object side of the first lens E1 to the image side of the fourth lens E4 is 1.99 mm.

[0072] Table 3 shows the basic parameters of the optical imaging lens of Embodiment 2-1 / Embodiment 2-2, wherein the units of radius of curvature, thickness / distance and focal length are millimeters (mm). Table 4 shows the higher-order coefficients that can be used for each aspherical mirror surface of Embodiment 2-1 / Embodiment 2-2, wherein each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0073]

[0074] Table 3

[0075]

[0076] Table 4

[0077] Figure 8AThe on-axis chromatic aberration curves of the optical imaging lenses of Embodiment 2-1 / Embodiment 2-2 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 8B The astigmatism curves of the optical imaging lens of Embodiment 2-1 / Embodiment 2-2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 8C The distortion curves of the optical imaging lenses of Embodiment 2-1 / Embodiment 2-2 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 8D The magnification chromatic aberration curves of the optical imaging lenses of Embodiment 2-1 / Embodiment 2-2 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to... Figures 8A to 8D It can be seen that the optical imaging lens given in Example 2-1 / Example 2-2 can achieve good imaging quality.

[0078] Example 3

[0079] Example 3 includes Example 3-1 and Example 3-2. Refer to the following... Figures 9 to 11D The optical imaging lenses according to Embodiments 3-1 and 3-2 of this application are described. In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to those in Embodiment 1 will be omitted. Figure 9 and Figure 10 Schematic diagrams of the optical imaging lenses according to Embodiments 3-1 and 3-2 of this application are shown respectively.

[0080] like Figure 9 and Figure 10 As shown, the optical imaging lenses of Embodiments 3-1 and 3-2 both include, from the object side to the image side, the following components in sequence: aperture stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter, and imaging surface (not shown).

[0081] The first lens E1 has a positive focal length, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has a negative focal length, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has a positive focal length, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has a negative focal length, with its object-side surface S7 being convex and its image-side surface S8 being concave. The filter has an object-side surface S9 and an image-side surface S10. Light from the object passes sequentially through each surface S1 to S10 and is finally imaged on the imaging surface S11.

[0082] In Example 3-1, the inner diameter d1m of the image-side surface of the first spacer P1 of the optical imaging lens is 1.320 mm, the inner diameter d1s of the object-side surface of the first spacer P1 is 1.364 mm, the outer diameter D1m of the image-side surface of the first spacer P1 is 2.200 mm, the outer diameter D2m of the image-side surface of the second spacer P2 and the outer diameter D2s of the object-side surface of the second spacer P2 are both 3.300 mm, the inner diameter d2s of the object-side surface of the second spacer P2 is 1.792 mm, the inner diameter d2m of the image-side surface of the second spacer P2 is 1.685 mm, the outer diameter D3s of the object-side surface of the third spacer P3 is 3.400 mm, the spacing EP12 between the first spacer P1 and the second spacer P2 is 0.465 mm, the maximum thickness CP1 of the first spacer P1 and the maximum thickness CP3 of the third spacer P3 are both 0.022 mm. The axial distance TD from the object-side surface of the first lens E1 to the image-side surface of the fourth lens E4 is 1.99 mm.

[0083] In Example 3-2, the inner diameter d1m of the image-side surface of the first spacer P1 of the optical imaging lens is 1.299 mm, the inner diameter d1s of the object-side surface of the first spacer P1 is 1.343 mm, the outer diameter D1m of the image-side surface of the first spacer P1 is 2.200 mm, the outer diameter D2m of the image-side surface of the second spacer P2 and the outer diameter D2s of the object-side surface of the second spacer P2 are both 3.300 mm, the inner diameter d2s of the object-side surface of the second spacer P2 is 1.785 mm, the inner diameter d2m of the image-side surface of the second spacer P2 is 1.741 mm, the outer diameter D3s of the object-side surface of the third spacer P3 is 3.400 mm, the spacing EP12 between the first spacer P1 and the second spacer P2 is 0.465 mm, the maximum thickness CP1 of the first spacer P1 and the maximum thickness CP3 of the third spacer P3 are both 0.022 mm. The axial distance TD from the object-side surface of the first lens E1 to the image-side surface of the fourth lens E4 is 2.01 mm.

[0084] Table 5 shows the basic parameters of the optical imaging lens of Embodiment 3-1 / Embodiment 3-2, wherein the units of radius of curvature, thickness / distance and focal length are millimeters (mm). Table 6 shows the higher-order coefficients that can be used for each aspherical mirror surface of Embodiment 3-1 / Embodiment 3-2, wherein each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0085]

[0086] Table 5

[0087]

[0088] Table 6

[0089] Figure 11AThe on-axis chromatic aberration curves of the optical imaging lenses of Embodiment 3-1 / Embodiment 3-2 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 11B The astigmatism curves of the optical imaging lenses of Embodiment 3-1 / Embodiment 3-2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 11C The distortion curves of the optical imaging lenses of Embodiment 3-1 / Embodiment 3-2 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 11D The magnification chromatic aberration curves of the optical imaging lenses of Embodiment 3-1 / Embodiment 3-2 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to... Figures 11A to 11D It can be seen that the optical imaging lens given in Example 3-1 / Example 3-2 can achieve good imaging quality.

[0090] In summary, Examples 1 to 3 respectively satisfy the relationships shown in Table 7.

[0091]

[0092] Table 7

[0093] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging lens described above.

[0094] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical imaging lens, characterized in that, Along the optical axis from the object side to the image side, the lenses sequentially include a first lens, a second lens, a third lens, and a fourth lens. The first lens has a positive focal length, and the radius of curvature of its object side is positive, and the radius of curvature of its image side is positive; The second lens has a negative focal length, and its object-side radius of curvature is negative while its image-side radius of curvature is positive. The third lens has a positive focal length, and its object-side radius of curvature is negative, as is its image-side radius of curvature. The fourth lens has a negative focal length, and its object-side radius of curvature is positive, as is its image-side radius of curvature. The optical imaging lens has four lenses with optical power. At least one spacer is provided between any two adjacent lenses from the first lens to the fourth lens, and between the fourth lens and the image side. The spacer that contacts the image side of the first lens is the first spacer, the spacer that contacts the image side of the second lens is the second spacer, the spacer that contacts the image side of the third lens is the third spacer, and the spacer that directly contacts the image side of the fourth lens is the fourth spacer. The optical imaging lens satisfies: 23.42 ≤ CP2 D3s / (T23 CP3)≤49.12, -11.0≤(R3) D2m) / (R2 D1m)≤-2.13,1.81≤T12 / T23≤3.53,11.35≤f1 / T12≤13.30, Wherein, CP2 is the maximum thickness of the second spacer, CP3 is the maximum thickness of the third spacer, D3s is the outer diameter of the object side of the third spacer, T23 is the spacing distance between the second lens and the third lens on the optical axis, R2 is the radius of curvature of the image side of the first lens, R3 is the radius of curvature of the object side of the second lens, D1m is the outer diameter of the image side of the first spacer, D2m is the outer diameter of the image side of the second spacer, T12 is the spacing distance between the first lens and the second lens on the optical axis, and f1 is the effective focal length of the first lens.

2. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 43.30≤EP12 f1 / (R1 CP1)≤52.79, Wherein, CP1 is the maximum thickness of the first spacer, EP12 is the spacing between the first spacer and the second spacer, f1 is the effective focal length of the first lens, and R1 is the radius of curvature of the object side of the first lens.

3. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 24.89≤R2 d1s / (CT1 R1-T12 R1)<46.0, Wherein, R2 is the radius of curvature of the image side of the first lens, d1s is the inner diameter of the object side of the first spacer, CT1 is the center thickness of the first lens on the optical axis, T12 is the spacing between the first lens and the second lens on the optical axis, and R1 is the radius of curvature of the object side of the first lens.

4. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: -11.20≤(R4 D2s) / (R5 D3s)≤-3.82, Wherein, R4 is the radius of curvature of the image side of the second lens, R5 is the radius of curvature of the object side of the third lens, D2s is the outer diameter of the object side of the second spacer, and D3s is the outer diameter of the object side of the third spacer.

5. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 11.0≤R7 / CP3+(R6 / T34)≤27.23, Wherein, R6 is the radius of curvature of the image side of the third lens, R7 is the radius of curvature of the object side of the fourth lens, T34 is the distance between the third lens and the fourth lens on the optical axis, and CP3 is the maximum thickness of the third spacer.

6. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 1.95≤(TD-d2s) / T23≤5.10, Wherein, TD is the axial distance from the object side of the first lens to the image side of the fourth lens, T23 is the distance between the second lens and the third lens on the optical axis, and d2s is the inner diameter of the object side of the second spacer.

7. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 5.5<(TD-d1m) / (CT1-CT2)≤7.05, Wherein, TD is the axial distance from the object side of the first lens to the image side of the fourth lens, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and d1m is the inner diameter of the image side of the first spacer.

8. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: -11.47≤f² / d²m≤-5.45, Where f2 is the effective focal length of the second lens, and d2m is the inner diameter of the image side of the second spacer.

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