Imaging lens

Abstract

The application relates to an imaging lens, comprising a lens barrel, a lens set and a plurality of spacer elements assembled in the lens barrel, the lens set sequentially comprises a first lens, a second lens, a third lens and a fourth lens from the object side to the image side, wherein the second lens is a super lens, and the image side of the second lens is a super surface; the plurality of spacer elements sequentially comprise a first spacer element located between the first lens and the second lens and abutting against the image side of the first lens, a second spacer element located between the second lens and the third lens and abutting against the image side of the second lens, and a third spacer element located between the third lens and the fourth lens and abutting against the image side of the third lens; and the imaging lens further satisfies 8.45 < L / (EP12 + CP2) < 11.00 and 9.95 < (d3s + d3m) / T34 < 13.25.

Description

Technical Field

[0001] This invention relates to the field of optical device technology, and in particular to an imaging lens. Background Technology

[0002] With the rapid development of foldable phones, the requirements for lenses are becoming increasingly stringent, with miniaturization and thinning gradually becoming the trend. Ensuring the performance of the lens optical system while pursuing miniaturization and thinning is a challenge in the research and development process, especially since the lens's stray light performance under high-light conditions directly reflects the upper limit of its optical performance.

[0003] The use of superlenses can improve the light-gathering efficiency of lenses, which helps to reduce the length of the lens along the optical axis, thereby promoting the miniaturization of lenses. It is worth noting that when a superlens is used, light rays will be sharply amplified after passing through the lens. This increased light can easily lead to stray light, which can actually reduce the performance of the optical system. Summary of the Invention

[0004] Given that existing imaging lenses are prone to stray light problems after using superlenses, it is necessary to provide an imaging lens.

[0005] According to one aspect of this application, an imaging lens is provided, including a lens barrel and a lens group and a plurality of spacers mounted in the lens barrel; the lens group, from the object side to the image side, sequentially includes: a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, and a fourth lens with negative optical power; the plurality of spacers, from the object side to the image side, sequentially includes: a first spacer, a second spacer, and a third spacer, wherein the first spacer is located between the first lens and the second lens and abuts against the image side of the first lens, the second spacer is located between the second lens and the third lens and abuts against the image side of the second lens, and the third spacer is located between the third lens and the image side of the second lens. The fourth lens is positioned between and abuts against the image-side surface of the third lens; the second lens is a superlens, and the image-side surface of the second lens is a metasurface; the imaging lens also satisfies: 8.45 < L / (EP12+CP2) < 11.00, 9.95 < (d3s+d3m) / T34 < 13.25, where L is the maximum height from the object-side surface of the lens barrel to the image-side surface of the lens barrel, EP12 is the distance along the optical axis from the image-side surface of the first spacer element to the object-side surface of the second spacer element, CP2 is the maximum thickness of the second spacer element along the optical axis, d3s is the inner diameter of the object-side surface of the third spacer element, d3m is the inner diameter of the image-side surface of the third spacer element, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

[0006] In some embodiments of this application, the imaging lens satisfies: 1.90 < ∑CT / (EP23+CP3) < 2.60; where ∑CT is the sum of the center thicknesses of the first lens, the second lens, the third lens, and the fourth lens along the optical axis, EP23 is the distance from the image side of the second spacer element to the object side of the third spacer element along the optical axis, and CP3 is the maximum thickness of the third spacer element along the optical axis.

[0007] In some embodiments of this application, the imaging lens satisfies: 0.45 < (D0m - d0m) / R8 < 1.40; where D0m is the outer diameter of the image side of the lens barrel, d0m is the inner diameter of the image side of the lens barrel, and R8 is the radius of curvature of the image side of the fourth lens.

[0008] In some embodiments of this application, the imaging lens satisfies: 0.90 < EP01 / (CT1+T12) < 1.55; where EP01 is the distance from the side of the lens barrel to the side of the first spacer element along the optical axis, CT1 is the center thickness of the first lens on the optical axis, and T12 is the air gap between the first lens and the second lens on the optical axis.

[0009] In some embodiments of this application, the imaging lens satisfies: 5.25≤(D1m-d1m) / CT2≤6.58; where D1m is the outer diameter of the image side of the first spacer element, d1m is the inner diameter of the image side of the first spacer element, and CT2 is the center thickness of the second lens on the optical axis.

[0010] In some embodiments of this application, the imaging lens satisfies: 3.03≤f2 / (d1s+d2s)≤4.35; where f2 is the effective focal length of the second lens, d1s is the inner diameter of the side surface of the first spacer element, and d2s is the inner diameter of the side surface of the second spacer element.

[0011] In some embodiments of this application, the imaging lens satisfies: 2.20 < (R2 + R3) / D1s < 2.85; where 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, and D1s is the outer diameter of the object side of the first spacer element.

[0012] In some embodiments of this application, the imaging lens satisfies: 2.60≤f1 / (D0s-d0s)≤6.19; where f1 is the effective focal length of the first lens, D0s is the outer diameter of the side surface of the lens barrel, and d0s is the inner diameter of the side surface of the lens barrel.

[0013] In some embodiments of this application, the imaging lens satisfies: 3.38≤d2m / T23≤4.75; where d2m is the inner diameter of the image side of the second spacer element, and T23 is the air gap between the second lens and the third lens on the optical axis.

[0014] In some embodiments of this application, the imaging lens satisfies: 2.25 < (D2s + D2m) / f < 3.20; where D2s is the outer diameter of the object side of the second spacer element, D2m is the outer diameter of the image side of the second spacer element, and f is the system focal length of the imaging lens.

[0015] In some embodiments of this application, the imaging lens satisfies: 9.05 < D3m / CT4 < 11.55; where D3m is the outer diameter of the image side of the third spacer element, and CT4 is the center thickness of the fourth lens on the optical axis.

[0016] In some embodiments of this application, the imaging lens satisfies: 1.30≤D3s / L≤2.22; where D3s is the outer diameter of the object side of the third spacer element, and L is the maximum height from the object side of the lens barrel to the image side of the lens barrel.

[0017] In some embodiments of this application, the imaging lens satisfies: 3.80≤f / (EP01+CP1)≤6.03; where f is the system focal length of the imaging lens, EP01 is the distance from the side of the lens barrel to the side of the first spacer element along the optical axis, and CP1 is the maximum thickness of the first spacer element along the optical axis.

[0018] In summary, the imaging lens in this application employs a four-element lens group, with the second lens being a superlens. Under the condition that 8.45 < L / (EP12+CP2) < 11.00, to ensure the machinability, strength, and assembly stability of the lenses, light intensity increases sharply after passing through the second lens. This results in stray light directly reflected onto the third spacer element, as well as stray light reflected from the filter (IR) onto the spacer element. This stray light affects image quality, especially under high brightness or strong light source conditions. By controlling the condition 9.95 < (d3s+d3m) / T34 < 13.25, direct reflection of light passing through the second and third lenses onto the inner inclined surface of the spacer element is prevented. This also effectively reduces light reflected from the filter onto the inner inclined surface, improving the arc-shaped stray light problem generated by the third spacer element itself and enhancing overall image quality. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the parameters of an imaging lens according to one embodiment of the present application;

[0020] Figure 2This is a schematic diagram of the imaging lens according to Embodiment 1 of this application;

[0021] Figure 3 This is a schematic diagram of the imaging lens according to Embodiment 2 of this application;

[0022] Figure 4 This is a schematic diagram of the imaging lens according to Embodiment 3 of this application;

[0023] Figure 5A A schematic diagram of the on-axis chromatic aberration curves of the imaging lenses according to the above-described Embodiment 1, Embodiment 2 and Embodiment 3 of this application is shown.

[0024] Figure 5B A schematic diagram of the astigmatism curves of the imaging lenses according to the above-described Embodiment 1, Embodiment 2 and Embodiment 3 of this application is shown.

[0025] Figure 5C The diagram shows the distortion curves of the imaging lenses according to Embodiment 1, Embodiment 2 and Embodiment 3 of this application.

[0026] Figure 6 This is a schematic diagram of the imaging lens according to Embodiment 4 of this application;

[0027] Figure 7 This is a schematic diagram of the imaging lens according to Embodiment 5 of this application;

[0028] Figure 8 This is a schematic diagram of the imaging lens according to Embodiment Six of this application;

[0029] Figure 9A A schematic diagram of the on-axis chromatic aberration curves of the imaging lenses according to Embodiments 4, 5 and 6 of this application is shown.

[0030] Figure 9B A schematic diagram of the astigmatism curves of the imaging lenses according to Embodiments 4, 5 and 6 of this application is shown.

[0031] Figure 9C A schematic diagram of the distortion curves of the imaging lenses according to Embodiments 4, 5 and 6 of this application is shown.

[0032] Figure 10 This is a schematic diagram of the imaging lens according to Embodiment 7 of this application;

[0033] Figure 11 This is a schematic diagram of the imaging lens according to Embodiment 8 of this application;

[0034] Figure 12This is a schematic diagram of the imaging lens according to Embodiment 9 of this application;

[0035] Figure 13A A schematic diagram of the on-axis chromatic aberration curve of the imaging lens according to Embodiments 7, 8 and 9 of this application is shown.

[0036] Figure 13B A schematic diagram of the astigmatism curves of the imaging lenses according to Embodiments 7, 8 and 9 of this application is shown.

[0037] Figure 13C A schematic diagram of the distortion curves of the imaging lenses according to Embodiments 7, 8 and 9 of this application is shown.

[0038] Figure 14A The image shows the spot pattern when the imaging lens satisfies L / (EP12+CP2)=9.71 and (d3s+d3m) / T34=11.9;

[0039] Figure 14B for Figure 14A The light path diagram corresponding to the light spot diagram shown;

[0040] Figure 15A The image shows the spot pattern when the imaging lens satisfies L / (EP12+CP2)=9.71 and (d3s+d3m) / T34=13.8;

[0041] Figure 15B for Figure 15A The light path diagram corresponding to the light spot diagram shown;

[0042] Figure 16A The image shows the spot pattern when the imaging lens satisfies L / (EP12+CP2)=9.71 and (d3s+d3m) / T34=9.1;

[0043] Figure 16B for Figure 16A The light path diagram corresponding to the light spot pattern shown.

[0044] Figure label:

[0045] E1, First lens; E2, Second lens; E3, Third lens; E4, Fourth lens; E5, Filter; P0, Lens barrel; P1, First spacer element; P2, Second spacer element; P3, Third spacer element. Detailed Implementation

[0046] 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.

[0047] 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.

[0048] 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.

[0049] In this paper, 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 shape in the paraxial region can be determined according to methods commonly used in the art, such as using the sign of the R value (R refers to the radius of curvature of the paraxial region) to determine concavity or convexity. In this paper, 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. For the object-side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the image-side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0050] 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.

[0051] 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 a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The following embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this application. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] Please see Figure 1 According to one aspect of this application, one embodiment provides an imaging lens, including a lens barrel P0 and a lens group and a plurality of spacers housed in the lens barrel P0; the lens group, from the object side to the image side, sequentially includes: a first lens E1 having positive optical power, a second lens E2 having positive optical power, a third lens E3 having negative optical power, and a fourth lens E4 having negative optical power; the plurality of spacers, from the object side to the image side, sequentially include: a first spacer P1, a second spacer P2, and a third spacer P3, wherein the first spacer P1 is located between the first lens E1 and the second lens E2 and abuts against the image side of the first lens E1, the second spacer P2 is located between the second lens E2 and the third lens E3 and abuts against the image side of the second lens E2, and the third spacer P3 is located between the object side and the third lens E3. The third lens E3 is positioned between and abuts against the image-side surface of the third lens E3; the second lens E2 is a superlens, and the image-side surface of the second lens E2 is a metasurface; the imaging lens also satisfies: 8.45 < L / (EP12+CP2) < 11.00, 9.95 < (d3s+d3m) / T34 < 13.25, where L is the maximum height from the object-side surface of the lens barrel P0 to the image-side surface of the lens barrel P0, EP12 is the distance along the optical axis from the image-side surface of the first spacer element P1 to the object-side surface of the second spacer element P2, CP2 is the maximum thickness of the second spacer element P2 along the optical axis, d3s is the inner diameter of the object-side surface of the third spacer element P3, d3m is the inner diameter of the image-side surface of the third spacer element P3, and T34 is the air gap between the third lens E3 and the fourth lens E4 on the optical axis.

[0054] According to the aforementioned imaging lens, the imaging lens in this application employs a four-lens optical system. The second lens E2 is a superlens, and the thickness of the edge structure of the second lens E2 and the thickness of the second spacer element P2 along the optical axis are constrained by the relationship 8.45 < L / (EP12+CP2) < 11.00, ensuring the lens's manufacturability, strength, and assembly stability. However, light rays experience a sharp increase after passing through the second lens E2, resulting in stray light directly reflected to the third spacer element P3 and stray light reflected from the filter E5 (IR) onto the spacer element. This stray light affects image quality, especially under high brightness or strong light source environments. By controlling the condition 9.95 < (d3s+d3m) / T34 < 13.25, direct reflection of light rays passing through the second lens E2 and the third lens E3 onto the inner inclined surface of the spacer element is prevented. This also effectively reduces light reflected from the filter E5 onto the inner inclined surface, improving the arc-shaped stray light problem generated by the third spacer element P3 itself and enhancing the overall image quality.

[0055] It is worth noting that, Figure 14A The image shows the light spot pattern when the imaging lens satisfies L / (EP12+CP2)=9.71 and (d3s+d3m) / T34=11.9 at a light incident angle of 48°. Figure 14B for Figure 14A The light path diagram corresponding to the light spot diagram shown in the figure can be easily seen from the figure. When the imaging lens satisfies the constraint of the relationship 9.95<(d3s+d3m) / T34<13.25, the light path is normal, there is no stray light generated at the position of the reflecting structure, and the imaging quality is better. Figure 15A The image shows the light spot pattern when the imaging lens satisfies L / (EP12+CP2)=9.71 and (d3s+d3m) / T34=13.8 at a light incident angle of 48°. Figure 15B for Figure 15A The light path diagram corresponding to the light spot diagram shown in the figure is easy to see from the figure. When the relationship (d3s+d3m) / T34 satisfied by the imaging lens exceeds the upper limit, there is a stray light problem above the light source. The light reflected from the filter E5 to the inner inclined surface of the third spacer element P3 will enter the picture and form an arc-shaped stray light, resulting in a decrease in image quality. Figure 16A The diagram shows the light spot when the imaging lens satisfies L / (EP12+CP2)=9.71 and (d3s+d3m) / T34=9.1 at a light incident angle of 48°. Figure 16B for Figure 16AThe light path diagram corresponding to the light spot diagram shown in the figure is easy to see. When the relationship (d3s+d3m) / T34 satisfied by the imaging lens exceeds the lower limit, there is a stray light problem below the light source. The light transmitted from the third lens E3 will be blocked by the inner inclined surface of the third spacer element P3. Some light is easily reflected directly into the image by the inner inclined surface of the third spacer element P3, thus forming stray light and causing a decrease in image quality.

[0056] According to some embodiments of this application, the imaging lens satisfies: 1.90 < ∑CT / (EP23+CP3) < 2.60; where ∑CT is the sum of the center thicknesses of the first lens E1, the second lens E2, the third lens E3, and the fourth lens E4 along the optical axis; EP23 is the distance along the optical axis from the image side of the second spacer element P2 to the object side of the third spacer element P3; and CP3 is the maximum thickness of the third spacer element P3 along the optical axis. Since the step difference between the third lens E3 and the fourth lens E4 is large, the thickness of the third lens E3 and the thickness of the spacer element are reasonably allocated by rationally controlling the value of the relationship ∑CT / (EP23+CP3), thereby improving the stability of the optical performance of the imaging lens while ensuring manufacturability.

[0057] According to some embodiments of this application, the imaging lens satisfies: 0.45 < (D0m - d0m) / R8 < 1.40; where D0m is the outer diameter of the image-side surface of the lens barrel P0, d0m is the inner diameter of the image-side surface of the lens barrel P0, and R8 is the radius of curvature of the image-side surface of the fourth lens E4. By reasonably controlling the range of values ​​for this relationship, while ensuring the width of the test support, the light height can be further controlled, avoiding performance testing problems caused by excessively low light height.

[0058] According to some embodiments of this application, the imaging lens satisfies: 0.90 < EP01 / (CT1+T12) < 1.55; where EP01 is the distance along the optical axis from the object side of the lens barrel P0 to the object side of the first spacer element P1, CT1 is the center thickness of the first lens E1 on the optical axis, and T12 is the air gap between the first lens E1 and the second lens E2 on the optical axis. By controlling the relationship EP01 / (CT1+T12) within a reasonable range, the manufacturability of the first lens E1 and the assembly thickness requirements of the front end of the lens barrel P0 can be effectively guaranteed, ensuring performance stability.

[0059] According to some embodiments of this application, the imaging lens satisfies: 5.25 ≤ (D1m - d1m) / CT2 ≤ 6.58; where D1m is the outer diameter of the image-side surface of the first spacer element P1, d1m is the inner diameter of the image-side surface of the first spacer element P1, and CT2 is the center thickness of the second lens E2 on the optical axis. (D1m - d1m) is the annular width of the first spacer element P1. By controlling (D1m - d1m) / CT2, the outer diameter-to-center thickness ratio of the second lens E2 can be effectively guaranteed. Since the second lens E2 is crucial in the entire optical system, ensuring the manufacturability of the second lens E2 can effectively improve the performance of the entire optical system.

[0060] According to some embodiments of this application, the imaging lens satisfies: 3.03 ≤ f2 / (d1s+d2s) ≤ 4.35; where f2 is the effective focal length of the second lens E2, d1s is the inner diameter of the object-side surface of the first spacer element P1, and d2s is the inner diameter of the object-side surface of the second spacer element P2. Light passing through the second lens E2 is prone to stray light; by controlling f2 / (d1s+d2s) within a reasonable range, stray light can be effectively reduced, and the lens imaging quality can be improved.

[0061] According to some embodiments of this application, the imaging lens satisfies: 2.20 < (R2 + R3) / D1s < 2.85; where R2 is the radius of curvature of the image side of the first lens E1, R3 is the radius of curvature of the object side of the second lens E2, and D1s is the outer diameter of the object side of the first spacer element P1. Reasonably controlling the range of this relationship can ensure the curvature of the first lens E1 and the second lens E2, as well as the outer diameter, structure, and effective optical diameter of the lenses, thus guaranteeing the manufacturability of the first two lenses.

[0062] According to some embodiments of this application, the imaging lens satisfies: 2.60 ≤ f1 / (D0s-d0s) ≤ 6.19; where f1 is the effective focal length of the first lens E1, D0s is the outer diameter of the object side of the lens barrel P0, and d0s is the inner diameter of the object side of the lens barrel P0. The difference (D0s-d0s) is actually the width of the lens top surface support. By controlling f1 / (D0s-d0s) within a reasonable range, the step difference between the first lens E1 and the top surface support can be reduced. During assembly, the force misalignment can be effectively avoided from affecting the surface shape of the first lens E1, thus ensuring the optical performance of the entire lens.

[0063] According to some embodiments of this application, the imaging lens satisfies: 3.38 ≤ d2m / T23 ≤ 4.75; where d2m is the inner diameter of the image side of the second spacer element P2, and T23 is the air gap between the second lens E2 and the third lens E3 on the optical axis. Since excessively large gaps between the second lens E2 and the third lens E3 can also lead to significant stray light, reasonably controlling this condition range allows the second spacer element P2 to effectively intercept this stray light, thereby improving the lens imaging quality.

[0064] According to some embodiments of this application, the imaging lens satisfies: 2.25 < (D2s + D2m) / f < 3.20; where D2s is the outer diameter of the object side of the second spacer element P2, D2m is the outer diameter of the image side of the second spacer element P2, and f is the system focal length of the imaging lens. By controlling the ratio (D2s + D2m) / f, the outer diameter of the second spacer element P2 can be ensured to be within a reasonable range. Since the current lens barrel P0 has a relatively thin wall thickness, controlling the outer diameter can effectively ensure the thickness uniformity of the lens barrel P0, ensure the strength of the lens barrel P0 and the structural stability during the assembly and reliability testing of the entire lens barrel P0, and reduce the influence of external factors on the lens.

[0065] According to some embodiments of this application, the imaging lens satisfies: 9.05 < D3m / CT4 < 11.55; where D3m is the outer diameter of the image side of the third spacer element P3, and CT4 is the center thickness of the fourth lens E4 on the optical axis. Since the filling process during molding can also lead to stray light risks due to appearance and bonding line issues, controlling the outer diameter-to-center thickness ratio of the fourth lens E4 within a reasonable range using the relationship D3m / CT4 can effectively ensure the lens's manufacturability, thereby effectively avoiding this stray light risk.

[0066] According to some embodiments of this application, the imaging lens satisfies: 1.30 ≤ D3s / L ≤ 2.22; where D3s is the outer diameter of the object side of the third spacer element P3, and L is the maximum height from the object side of the lens barrel P0 to the image side of the lens barrel P0. By controlling the D3s / L ratio, the total height of the lens can be effectively controlled, ensuring the lens's thin and light characteristics, which is in line with the trend of lens miniaturization.

[0067] According to some embodiments of this application, the imaging lens satisfies: 3.80 ≤ f / (EP01+CP1) ≤ 6.03; where f is the system focal length of the imaging lens, EP01 is the distance along the optical axis from the object side of the lens barrel P0 to the object side of the first spacer element P1, and CP1 is the maximum thickness of the first spacer element P1 along the optical axis. By controlling the f / (EP01+CP1) ratio to be within a reasonable range, the field curvature stability of the lens optical system can be ensured, and the performance can be optimized and improved by adjusting the thickness of the spacer element.

[0068] It should be noted that those skilled in the art should understand that, without departing from the technical solutions claimed in this application, the number of spacers constituting the imaging lens can be changed to obtain the various results and advantages described in this specification, and this application does not specifically limit this. For example, as needed, the optical imaging lens may also include other numbers of spacers than those described in the above embodiments.

[0069] The following describes in more detail some specific, non-limiting embodiments of the above-described embodiments of this application with reference to the accompanying drawings. For ease of description, in the following embodiments, OBJ represents the object plane of the imaging lens, STO represents the surface of the aperture stop, S1 represents the object-side plane of the first lens E1, S2 represents the image-side plane of the first lens E1, S3 represents the object-side plane of the second lens E2, S4 represents the image-side plane of the second lens E2, S5 represents the object-side plane of the third lens E3, S6 represents the image-side plane of the third lens E3, S7 represents the object-side plane of the fourth lens E4, S8 represents the image-side plane of the fourth lens E4, S9 represents the object-side plane of the fifth lens, S10 represents the image-side plane of the fifth lens, and S11 represents the image plane.

[0070] Example 1

[0071] like Figure 2 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0072] In this embodiment, the first lens E1 has positive optical power, the object side of the first lens E1 is convex and the image side is concave; the second lens E2 has positive optical power, the object side of the second lens E2 is convex and the image side is flat; the third lens E3 has negative optical power, the object side of the third lens E3 is concave and the image side is convex; and the fourth lens E4 has negative optical power, the object side of the fourth lens E4 is convex and the image side is concave.

[0073] In addition, Table 1 shows the basic optical parameters of the optical imaging lens of Embodiment 1, where the units for radius of curvature and thickness are millimeters (mm).

[0074] Table 1

[0075]

[0076] In this embodiment, the object-side surface and image-side surface of any one of the first lens E1, the third lens E3, and the fourth lens E4 are aspherical, and the object-side surface of the second lens E2 is aspherical. The surface shape x of each aspherical surface can be defined using, but is not limited to, the following aspherical formula:

[0077]

[0078] Where x is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Tables 2-1 and 2-2 below give the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical surface S1, S2, S3, S5, S6, S7, and S8 in Example 1.

[0079] Table 2-1

[0080]

[0081] Table 2-2

[0082]

[0083] In this embodiment, the image-side surface of the second lens E2 is a metasurface, which can be defined using, but is not limited to, the following metasurface phase equation:

[0084] ;

[0085] Where φ(r) is the phase profile, d is the diffraction order, λ0 is the reference wavelength, r is the radial coordinate, and Ci is the coefficient of the metasurface phase equation, i=1, 2, 3, 4, 5.

[0086] Table 3 below gives the coefficient values ​​of the metasurface phase equation applicable to S4 in this embodiment.

[0087] Table 3

[0088]

[0089] Example 2

[0090] like Figure 3 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0091] It is worth noting that, compared with Embodiment 1 above, the imaging lens of Embodiment 2 has the same optical parameters. That is, the basic optical parameter table of the imaging lens of Embodiment 2 is the same as Table 1, the aspherical coefficient table is the same as Tables 2-1 and 2-2, and the phase equation coefficient is the same as Table 3. However, the imaging lens of Embodiment 2 has different structural parameters than the imaging lens of Embodiment 1 above. That is, the difference between Embodiment 2 and Embodiment 1 above lies in the different dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the imaging lens.

[0092] Specifically, the values ​​of the relevant structural parameters in Embodiment 2 and Embodiment 1 above are shown in Table 11 below. It should be understood that the units of the values ​​for each parameter shown in Table 11 are millimeters (mm), and the schematic diagrams of each parameter in the imaging lens structure are as follows... Figure 1 As shown.

[0093] Example 3

[0094] like Figure 4 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0095] It is worth noting that, compared with Embodiment 1 above, the imaging lens of Embodiment 3 has the same optical parameters. That is, the basic optical parameter table of the imaging lens of Embodiment 3 is the same as Table 1, the aspherical coefficient table is the same as Tables 2-1 and 2-2, and the phase equation coefficient is the same as Table 3. However, the imaging lens of Embodiment 3 has different structural parameters than the imaging lens of Embodiment 1 above. That is, the difference between Embodiment 3 and Embodiment 1 above lies in the different dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the imaging lens.

[0096] In conclusion, Figure 5A The on-axis chromatic aberration curves of the imaging lenses in Embodiments 1, 2, and 3 are shown, representing the degree of deflection of the focal point after light of different wavelengths passes through the imaging lens. Figure 5B The on-axis astigmatism curves of the imaging lenses in Embodiments 1, 2, and 3 are shown, representing the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 5C The distortion curves of the imaging lenses in Embodiments 1, 2, and 3 are shown, representing the relative deviation between the actual image and the ideal image. According to... Figure 5A , Figure 5B and Figure 5C It can be seen that the imaging lenses in Embodiment 1, Embodiment 2 and Embodiment 3 can all achieve good imaging quality.

[0097] Example 4

[0098] like Figure 6 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0099] In this embodiment, the first lens E1 has positive optical power, the object side of the first lens E1 is convex and the image side is concave; the second lens E2 has positive optical power, the object side of the second lens E2 is convex and the image side is flat; the third lens E3 has negative optical power, the object side of the third lens E3 is concave and the image side is convex; and the fourth lens E4 has negative optical power, the object side of the fourth lens E4 is convex and the image side is concave.

[0100] In addition, Table 4 shows the basic optical parameters of the optical imaging lens of Embodiment 7, where the units for radius of curvature and thickness are millimeters (mm).

[0101] Table 4

[0102]

[0103] In this embodiment, the object-side surface and image-side surface of any one of the first lens E1, the third lens E3, and the fourth lens E4 are aspherical, and the object-side surface of the second lens E2 is aspherical. The surface shape x of each aspherical lens can be defined using, but is not limited to, the aspherical formula in Embodiment 1.

[0104] Tables 5-1 and 5-2 below give the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical surface S1, S2, S3, S5, S6, S7, and S8 in Example 4.

[0105] Table 5-1

[0106]

[0107] Table 5-2

[0108]

[0109] In this embodiment, the image-side surface of the second lens E2 is a metasurface, which can be defined using, but is not limited to, the metasurface phase equation in Embodiment 1.

[0110] Table 6 below gives the coefficient values ​​of the metasurface phase equation applicable to S4 in this embodiment.

[0111] Table 6

[0112]

[0113] Example 5

[0114] like Figure 7As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0115] It is worth noting that, compared with Embodiment 4 above, the imaging lens of Embodiment 5 has the same optical parameters. That is, the basic optical parameter table of the imaging lens of Embodiment 5 is the same as Table 4, the aspherical coefficient table is the same as Tables 5-1 and 5-2, and the phase equation coefficient is the same as Table 6. However, the imaging lens of Embodiment 5 has different structural parameters than the imaging lens of Embodiment 4 above. That is, the difference between Embodiment 5 and Embodiment 4 above is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the imaging lens are different.

[0116] Specifically, the values ​​of the relevant structural parameters in Embodiment 5 and Embodiment 4 above are shown in Table 11 below. It should be understood that the unit of the values ​​of each parameter shown in Table 11 is millimeters (mm), and the schematic diagram of each parameter in the imaging lens structure is shown below. Figure 1 As shown.

[0117] Example 6

[0118] like Figure 8 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0119] It is worth noting that, compared with Embodiment 4 above, the imaging lens of Embodiment 6 has the same optical parameters. That is, the basic optical parameter table of the imaging lens of Embodiment 6 is the same as Table 4, the aspherical coefficient table is the same as Tables 5-1 and 5-2, and the phase equation coefficient is the same as Table 6. However, the imaging lens of Embodiment 6 has different structural parameters than the imaging lens of Embodiment 4 above. That is, the difference between Embodiment 6 and Embodiment 4 above lies in the different dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the imaging lens.

[0120] Specifically, the values ​​of the relevant structural parameters in Embodiment Six and Embodiment Four are shown in Table 11 below. It should be understood that the units of the values ​​shown in Table 11 are millimeters (mm), and the schematic diagrams of the parameters in the imaging lens structure are as follows: Figure 1 As shown.

[0121] In conclusion, Figure 9A The on-axis chromatic aberration curves of the imaging lenses in Embodiments 4, 5, and 6 are shown, representing the degree of deflection of the focal point after light of different wavelengths passes through the imaging lens. Figure 9B The on-axis astigmatism curves of the imaging lenses in Embodiments 4, 5, and 6 are shown, representing the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 9C The distortion curves of the imaging lenses in Embodiments 4, 5, and 6 are shown, representing the relative deviation between the actual image and the ideal image. According to... Figure 9A , Figure 9B and Figure 9C It can be seen that the imaging lenses in Embodiments 4, 5 and 6 can all achieve good imaging quality.

[0122] Example 7

[0123] like Figure 10 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0124] In this embodiment, the first lens E1 has positive optical power, the object side of the first lens E1 is convex and the image side is concave; the second lens E2 has positive optical power, the object side of the second lens E2 is convex and the image side is flat; the third lens E3 has negative optical power, the object side of the third lens E3 is concave and the image side is convex; and the fourth lens E4 has negative optical power, the object side of the fourth lens E4 is convex and the image side is concave.

[0125] In addition, Table 7 shows the basic optical parameters of the optical imaging lens of Embodiment 7, where the units for radius of curvature and thickness are millimeters (mm).

[0126] Table 7

[0127]

[0128] In this embodiment, the object-side surface and image-side surface of any one of the first lens E1, the third lens E3, and the fourth lens E4 are aspherical, and the object-side surface of the second lens E2 is aspherical. The surface shape x of each aspherical lens can be defined using, but is not limited to, the aspherical formula in Embodiment 1.

[0129] Tables 8-1 and 8-2 below give the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical surface S1, S2, S3, S5, S6, S7, and S8 in Example 7.

[0130] Table 8-1

[0131]

[0132] Table 8-2

[0133]

[0134] In this embodiment, the image-side surface of the second lens E2 is a metasurface, which can be defined using, but is not limited to, the metasurface phase equation in Embodiment 1.

[0135] Table 9 below gives the coefficient values ​​of the metasurface phase equation applicable to S4 in this embodiment.

[0136] Table 9

[0137]

[0138] Example 8

[0139] like Figure 11As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0140] It is worth noting that, compared with Embodiment 7 above, the imaging lens of Embodiment 8 has the same optical parameters. That is, the basic optical parameter table of the imaging lens of Embodiment 8 is the same as Table 7, the aspherical coefficient table is the same as Tables 8-1 and 8-2, and the phase equation coefficient is the same as Table 9. However, the imaging lens of Embodiment 8 has different structural parameters than the imaging lens of Embodiment 7 above. That is, the difference between Embodiment 8 and Embodiment 7 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the imaging lens are different.

[0141] Specifically, the values ​​of the relevant structural parameters in Embodiment 8 and Embodiment 7 are shown in Table 11 below. It should be understood that the units of the values ​​shown in Table 11 are millimeters (mm), and the schematic diagrams of the parameters in the imaging lens structure are as follows: Figure 1 As shown.

[0142] Example 9

[0143] like Figure 12 As shown, in this embodiment, the imaging lens includes a lens barrel P0 and a lens group and a plurality of spacers mounted within the lens barrel P0; the lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4; the plurality of spacers include, from the object side to the image side, a first spacer P1 positioned between the first lens E1 and the second lens E2 and abutting against the image side of the first lens E1, a second spacer P2 positioned between the second lens E2 and the third lens E3 and abutting against the image side of the second lens E2, and a third spacer P3 positioned between the third lens E3 and the fourth lens E4 and abutting against the image side of the third lens E3, wherein the second lens E2 is a superlens, and the image side of the second lens E2 is a metasurface.

[0144] It is worth noting that, compared with Embodiment 7 above, the imaging lens of Embodiment 9 has the same optical parameters. That is, the basic optical parameter table of the imaging lens of Embodiment 9 is the same as Table 7, the aspherical coefficient table is the same as Tables 8-1 and 8-2, and the phase equation coefficient is the same as Table 9. However, the imaging lens of Embodiment 9 has different structural parameters than the imaging lens of Embodiment 7 above. That is, the difference between Embodiment 9 and Embodiment 7 is that the dimensions of some structural parameters of the lens barrel P0 and multiple spacer elements in the imaging lens are different.

[0145] Specifically, the values ​​of the relevant structural parameters in Embodiment Nine and Embodiment Seven above are shown in Table 11 below. It should be understood that the unit of the values ​​of each parameter shown in Table 11 is millimeters (mm), and the schematic diagram of each parameter in the imaging lens structure is shown below. Figure 1 As shown.

[0146] In conclusion, Figure 13A The on-axis chromatic aberration curves of the imaging lenses in Embodiments 7, 8, and 9 are shown, representing the degree of deflection of the focal point after light of different wavelengths passes through the imaging lens. Figure 13B The on-axis astigmatism curves of the imaging lenses in Embodiments 7, 8, and 9 are shown, representing the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 13C The distortion curves of the imaging lenses in Embodiments 7, 8, and 9 are shown, representing the relative deviation between the actual image and the ideal image. According to... Figure 13A , Figure 13B and Figure 13C It can be seen that the imaging lenses in Embodiments 7, 8 and 9 can all achieve good imaging quality.

[0147] In summary, in Examples 1 to 9, the effective focal length f of the imaging lens, the effective focal lengths f1 to f4 of the first lens E1 to the fourth lens E4 in the imaging lens, the effective focal length f of the imaging lens, and the sum of the center thicknesses ∑CT of the first lens E1, the second lens E2, the third lens E3 and the fourth lens E4 in the imaging lens on the optical axis are shown in Table 10 below.

[0148] Table 10

[0149]

[0150] In addition, some structural parameters of the imaging lenses in Examples 1 to 9 are shown in Table 11.

[0151] Table 11

[0152]

[0153] In Table 11 above, the structural parameters are defined as follows: d1s is the inner diameter of the object side of the first spacer element P1, d1m is the inner diameter of the image side of the first spacer element P1, D1s is the outer diameter of the object side of the first spacer element P1, D1m is the outer diameter of the image side of the first spacer element P1, d2s is the inner diameter of the object side of the second spacer element P2, d2m is the inner diameter of the image side of the second spacer element P2, D2s is the outer diameter of the object side of the second spacer element P2, D2m is the outer diameter of the image side of the second spacer element P2, d3s is the inner diameter of the object side of the third spacer element P3, d3m is the inner diameter of the image side of the third spacer element P3, D3s is the outer diameter of the object side of the third spacer element P3, D3m is the outer diameter of the image side of the third spacer element P3, d0s is the inner diameter of the lens barrel P0 The inner diameter of the object side, d0m is the inner diameter of the image side of the lens barrel P0, D0s is the outer diameter of the object side of the lens barrel P0, D0m is the outer diameter of the image side of the lens barrel P0, EP01 is the distance from the object side of the lens barrel P0 to the object side of the first spacer element P1 along the optical axis, CP1 is the maximum thickness of the first spacer element P1 along the optical axis, EP12 is the maximum thickness from the image side of the first spacer element P1 to the object side of the second spacer element P2 along the optical axis, CP2 is the maximum thickness of the second spacer element P2 along the optical axis, EP23 is the distance from the image side of the second spacer element P2 to the object side of the third spacer element P3 along the optical axis, CP3 is the maximum thickness of the third spacer element P3 along the optical axis, and L is the maximum height from the object side of the lens barrel P0 to the image side of the lens barrel P0.

[0154] In summary, the imaging lenses in Examples 1 to 9 satisfy the relationships in Table 12.

[0155] Table 12

[0156]

[0157] It is worth mentioning that, according to one aspect of this application, one embodiment of this application further provides a camera module, which may include the aforementioned imaging lens and a photosensitive element, the photosensitive element being disposed on the image side of the imaging lens for imaging. It is understood that the photosensitive element mentioned in this application may, but is not limited to, be implemented as a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) device, and this application will not elaborate further on this.

[0158] Furthermore, according to another aspect of this application, one embodiment of this application provides an electronic device that may include a camera module and a processor as described above. The camera module is communicatively connected to the processor for acquiring image data and inputting the image data into the processor for processing. It is understood that the electronic device mentioned in this application may, but is not limited to, a device such as a mobile phone equipped with the camera module, and this application will not elaborate further on this.

[0159] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0160] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An imaging lens, comprising a lens barrel and a lens group and a plurality of spacer elements mounted in the lens barrel, characterized in that: The lens group, from the object side to the image side, includes, in sequence: a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, and a fourth lens with negative optical power. The imaging lens has four lenses with optical power. The object-side surface and image-side surface of the first lens are convex and concave, respectively; the object-side surface and image-side surface of the second lens are convex and flat, respectively; the object-side surface and image-side surface of the third lens are concave and convex, respectively; and the object-side surface and image-side surface of the fourth lens are convex and concave, respectively. The plurality of spacers, from the object side to the image side, sequentially include: a first spacer, a second spacer, and a third spacer, wherein the first spacer is located between the first lens and the second lens and abuts against the image side of the first lens, the second spacer is located between the second lens and the third lens and abuts against the image side of the second lens, and the third spacer is located between the third lens and the fourth lens and abuts against the image side of the third lens; The second lens is a superlens, and the image-side surface of the second lens is a metasurface; The imaging lens also satisfies the following conditions: 8.45 < L / (EP12+CP2) < 11.00, 9.95 < (d3s+d3m) / T34 < 13.25, 3.03 ≤ f2 / (d1s+d2s) ≤ 4.35, and 2.60 ≤ f1 / (D0s-d0s) ≤ 6.19, where L is the maximum height from the object side of the lens barrel to the image side of the lens barrel, EP12 is the distance along the optical axis from the image side of the first spacer element to the object side of the second spacer element, and CP2 is the distance along the optical axis from the image side of the first spacer element to the object side of the second spacer element. The maximum thickness of the spacer element along the optical axis, d3s is the inner diameter of the object side of the third spacer element, d3m is the inner diameter of the image side of the third spacer element, T34 is the air gap between the third lens and the fourth lens on the optical axis, f2 is the effective focal length of the second lens, d1s is the inner diameter of the object side of the first spacer element, d2s is the inner diameter of the object side of the second spacer element, f1 is the effective focal length of the first lens, D0s is the outer diameter of the object side of the lens barrel, and d0s is the inner diameter of the object side of the lens barrel.

2. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 1.90 < ∑CT / (EP23+CP3) < 2.60; where ∑CT is the sum of the center thicknesses of the first lens, the second lens, the third lens and the fourth lens on the optical axis, EP23 is the distance from the image side of the second spacer element to the object side of the third spacer element along the optical axis, and CP3 is the maximum thickness of the third spacer element along the optical axis.

3. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 0.45 < (D0m - d0m) / R8 < 1.40; where D0m is the outer diameter of the image side of the lens barrel, d0m is the inner diameter of the image side of the lens barrel, and R8 is the radius of curvature of the image side of the fourth lens.

4. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 0.90 < EP01 / (CT1 + T12) < 1.55; where EP01 is the distance from the side of the lens barrel to the side of the first spacer element along the optical axis, CT1 is the center thickness of the first lens on the optical axis, and T12 is the air gap between the first lens and the second lens on the optical axis.

5. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 5.25≤(D1m-d1m) / CT2≤6.58; where D1m is the outer diameter of the image side of the first spacer element, d1m is the inner diameter of the image side of the first spacer element, and CT2 is the center thickness of the second lens on the optical axis.

6. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 2.20 < (R2 + R3) / D1s < 2.85; where 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, and D1s is the outer diameter of the object side of the first spacer element.

7. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 3.38≤d2m / T23≤4.75; where d2m is the inner diameter of the image side of the second spacer element, and T23 is the air gap between the second lens and the third lens on the optical axis.

8. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 2.25 < (D2s + D2m) / f < 3.20; where D2s is the outer diameter of the object side of the second spacer element, D2m is the outer diameter of the image side of the second spacer element, and f is the system focal length of the imaging lens.

9. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 9.05 < D3m / CT4 < 11.55; where D3m is the outer diameter of the image side of the third spacer element, and CT4 is the center thickness of the fourth lens on the optical axis.

10. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 1.30≤D3s / L≤2.22; where D3s is the outer diameter of the object side of the third spacer element, and L is the maximum height from the object side of the lens barrel to the image side of the lens barrel.

11. The imaging lens according to claim 1, characterized in that, The imaging lens satisfies: 3.80≤f / (EP01+CP1)≤6.03; where f is the system focal length of the imaging lens, EP01 is the distance from the side of the lens barrel to the side of the first spacer element along the optical axis, and CP1 is the maximum thickness of the first spacer element along the optical axis.

Images