Optical imaging system

Abstract

The application discloses an optical imaging system, which comprises: a lens group, comprising a first lens, a second lens, a third lens and a fourth lens arranged in sequence from an object side to an image side along an optical axis; at least one spacer element, the spacer element comprising a third spacer element located between the third lens and the fourth lens and directly contacting an image side surface of the third lens; and a lens barrel for accommodating the lens group and the spacer element; wherein an outer diameter D3m of an image side surface of the third spacer element, an outer diameter D3s of an object side surface of the third spacer element and a curvature radius R8 of an image side surface of the fourth lens satisfy: 0.5<|R8 / (D3s+D3m)|<9.5.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to an optical imaging system comprising four lenses. Background Technology

[0002] With the rapid development of the electronics industry, various electronic products are paying more attention to human-computer interaction, and the requirements for recognition systems are becoming increasingly stringent. This, in turn, leads to ever-increasing demands on camera performance and appearance. Furthermore, as electronic products become increasingly miniaturized and lighter, the size of various electronic components must also be reduced accordingly, while performance requirements continue to rise. Therefore, cameras require new optical imaging systems to meet the demands of smaller form factors while maintaining superior imaging performance. Summary of the Invention

[0003] This application provides an optical imaging system comprising: a lens group including a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side along the optical axis; at least one spacer element, the spacer element including a third spacer element located between the third lens and the fourth lens and in direct contact with the image side surface of the third lens; and a lens barrel for accommodating the lens group and the spacer element; wherein the outer diameter D3m of the image side surface of the third spacer element, the outer diameter D3s of the object side surface of the third spacer element, and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0.5 < |R8 / (D3s+D3m)| < 9.5.

[0004] In one or more embodiments, the spacer element further includes a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens.

[0005] In one or more embodiments, the air gap T12 between the first lens and the second lens on the optical axis, the sum of the air gaps ∑AT between any two adjacent lenses with optical power from the first lens to the lens closest to the imaging surface, the maximum thickness CP1 of the first spacer element, and the maximum height L of the lens barrel satisfy: 0.5 < (T12 * ∑AT) / (CP1 * L) < 1.0.

[0006] In one or more embodiments, the effective focal length f1 of the first lens, the center thickness CT1 of the first lens on the optical axis, the spacing EP01 between the front end face of the lens barrel near the object side and the first spacer element, and the maximum thickness P1 of the first spacer element satisfy: 113.0 < f1*CT1 / (EP01*CP1) < 336.0.

[0007] In one or more embodiments, the effective focal length f of the optical imaging system, the outer diameter D0s of the front end face of the lens barrel closest to the object side, the inner diameter d0s of the front end face of the lens barrel closest to the object side, the outer diameter D1s of the object side surface of the first spacer element, the inner diameter d1s of the object side surface of the first spacer element, and the effective focal length f1 of the first lens satisfy: 0.5 < f*(D0s-d0s) / (f1*(D1s-d1s)) < 3.0.

[0008] In one or more embodiments, the radius of curvature R1 of the object side of the first lens, the radius of curvature R2 of the image side of the first lens, the inner diameter d1s of the object side of the first spacer element, and the inner diameter d1m of the image side of the first spacer element satisfy: 1.0 < |R1+R2| / (d1s+d1m) < 5.0.

[0009] In one or more embodiments, the spacer element further includes a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens.

[0010] In one or more embodiments, the effective focal length f2 of the second lens, the spacing EP12 between the first and second spacers, the maximum thickness CP2 of the second spacer, and the air spacing T23 between the second and third lenses on the optical axis satisfy: 2.5 < |f2*EP12| / (CP2*T23) < 6.0.

[0011] In one or more embodiments, the combined focal length f12 of the first lens and the second lens, the inner diameter d2m of the image side of the second spacer element, and the inner diameter d2s of the object side of the second spacer element satisfy: 14.0 < f12 / (d2m-d2s) < 17.0.

[0012] In one or more embodiments, the radius of curvature R3 of the object side of the second lens, the radius of curvature R4 of the image side of the second lens, the center thickness CT2 of the second lens on the optical axis, the maximum thickness CP2 of the second spacer element, and the spacing EP23 between the second spacer element and the third spacer element satisfy: -27.0 < (R3 + R4) / (CP2 + CT2 + EP23) < -1.0.

[0013] In one or more embodiments, the radius of curvature R3 of the object side of the second lens, the center thickness CT3 of the third lens on the optical axis, the maximum thickness CP2 of the second spacer element, the outer diameter D2m of the image side of the second spacer element, and the inner diameter d2m of the image side of the second spacer element satisfy: 0.5 < |R5*CT3| / (CP2*(D2m+d2m)) < 1.5.

[0014] In one or more embodiments, the effective focal length f3 of the third lens, the effective focal length f4 of the fourth lens, the outer diameter D3s of the object side of the third spacer element, and the outer diameter D2m of the image side of the second spacer element satisfy: 0.0 < (f3 + f4) / (D3s - D2m) < 1.0.

[0015] In one or more embodiments, the combined focal length f34 of the third lens and the fourth lens, the maximum thickness CP3 of the third spacer element, the spacing EP23 between the second spacer element and the third spacer element, the center thickness CT3 of the third lens on the optical axis, and the air spacing T34 between the third lens and the fourth lens on the optical axis satisfy: 5.5 < f34 / (CP3+EP23+CT3+T34) < 12.5.

[0016] In one or more embodiments, the effective focal length f4 of the fourth lens, the radius of curvature R7 of the object side surface of the fourth lens, the inner diameter d3s of the object side surface of the third spacer element, and the maximum thickness CP3 of the third spacer element satisfy: 1.5 < |f4*R7| / (d3s*CP3) < 3.5.

[0017] In one or more embodiments, half of the maximum field of view (Semi-FOV) of the optical imaging system, the effective focal length (f) of the optical imaging system, the outer diameter (D0m) of the rear end face of the lens barrel closest to the image side, and the outer diameter (D3m) of the image side face of the third spacer element satisfy: 1.0 < TAN(Semi-FOV)*f / (D0m-D3m) < 2.0.

[0018] In one or more embodiments, the combined focal length f23 of the second lens and the third lens, the spacing EP12 between the first spacer element and the second spacer element, and the spacing EP23 between the second spacer element and the third spacer element satisfy: 2.5 < f23 / (EP12+EP23) < 6.5.

[0019] In one or more embodiments, the radius of curvature R5 of the object side of the third lens, the radius of curvature R6 of the image side of the third lens, the spacing EP12 between the first spacer element and the second spacer element, the maximum thickness CP2 of the second spacer element, and the air spacing T23 between the second lens and the third lens on the optical axis satisfy: 2.5 < |R5 + R6| / (EP12 + CP2 + T23) < 5.0.

[0020] The optical imaging system provided in this application includes a lens group and at least one spacer element. The lens group includes four lenses with optical power and may also include a lens barrel for housing the lens group and the spacer element. The spacer element may include a third spacer element located between the third and fourth lenses and in direct contact with the image-side surface of the third lens. By reasonably controlling the outer diameter parameters of the object-side and image-side surfaces of the third spacer element, the assembly step difference of the air gap between the third and fourth lenses can be reasonably controlled, resulting in better assembly stability. Simultaneously, in conjunction with the control of the curvature radius of the image-side surface of the fourth lens, the outgoing light rays can be well constrained, obtaining an image size that matches the design, thereby increasing pixel count and facilitating miniaturization. Attached Figure Description

[0021] 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:

[0022] Figure 1 A schematic diagram of the structure of an optical imaging system provided according to an embodiment of this application is shown;

[0023] Figure 2 A schematic diagram illustrating the elimination of stray light in an optical imaging system according to an embodiment of this application is shown;

[0024] Figure 3A and Figure 3B A schematic diagram of the structure of an optical imaging system according to Embodiment 1 of this application is shown;

[0025] Figures 4A to 4D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system according to Embodiment 1 of this application are shown respectively.

[0026] Figure 5A and Figure 5B A schematic diagram of the structure of an optical imaging system according to Embodiment 2 of this application is shown;

[0027] Figures 6A to 6D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system according to Embodiment 2 of this application are shown respectively.

[0028] Figure 7A and Figure 7B A schematic diagram of the structure of an optical imaging system according to Embodiment 3 of this application is shown;

[0029] Figures 8A to 8D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system according to Embodiment 3 of this application are shown respectively.

[0030] Figure 9A and Figure 9B A schematic diagram of the structure of an optical imaging system according to Embodiment 4 of this application is shown; and

[0031] Figures 10A to 10D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system according to Embodiment 4 of this application are shown respectively. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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 formalized sense, unless expressly so specified herein.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. For example, the lens groups (i.e., the first lens to the fourth lens), lens barrel structure, and spacer elements in the various embodiments of this application can be arbitrarily combined, and it is not limited to the lens group in one embodiment being only combined with the lens barrel structure, spacer elements, etc. of that embodiment.

[0039] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Figure 1 This diagram illustrates the structural layout and schematic diagram of some parameters of an optical imaging system according to this application. Those skilled in the art will understand that some parameters frequently used in the art, such as the center thickness CT1 of the first lens on the optical axis, are not shown. Figure 1 As shown in the figure, Figure 1 The illustration only shows partial parameters of the lens barrel and spacer elements of an optical imaging system according to this application, to facilitate a better understanding of the invention. Figure 1 As shown, L represents the maximum height of the lens barrel along the optical axis; EP01 represents the distance between the front end face of the lens barrel near the object side and the object side face of the first spacer element along the optical axis; EP12 represents the distance between the image side face of the first spacer element and the object side face of the second spacer element along the optical axis; CP1 represents the maximum thickness of the first spacer element along the optical axis; CP2 represents the maximum thickness of the second spacer element along the optical axis; D0s represents the outer diameter of the front end face of the lens barrel closest to the object side; d0s represents the inner diameter of the front end face of the lens barrel closest to the object side; D1s represents the outer diameter of the object side face of the first spacer element; d1s represents the inner diameter of the object side face of the first spacer element; D1m represents the outer diameter of the image side face of the first spacer element; d1m represents the inner diameter of the image side face of the first spacer element; d2s represents the inner diameter of the object side face of the second spacer element; d2m represents the inner diameter of the image side face of the second spacer element, and so on.

[0040] The features, principles and other aspects of this application are described in detail below.

[0041] An optical imaging system according to an exemplary embodiment of this application includes a lens barrel, a lens group, and at least one spacer element, wherein the lens group and one or more spacer elements are all housed within the lens barrel. The lens group may include four lenses with optical power, namely a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical path. These four lenses are arranged sequentially from the object side to the image side along the optical axis. Any two adjacent lenses among the first to fourth lenses may have a spacer distance.

[0042] In an exemplary embodiment, the spacer element includes at least a third spacer element between the third lens and the fourth lens, which is in direct contact with the image-side surface of the third lens. The outer diameter D3m of the image-side surface of the third spacer element, the outer diameter D3s of the object-side surface of the third spacer element, and the radius of curvature R8 of the image-side surface of the fourth lens satisfy the condition: 0.5 < |R8 / (D3s+D3m)| < 9.5. According to the optical imaging system of the exemplary embodiment of this application, by setting a third spacer element between the third lens and the fourth lens and satisfying the above condition, the outer diameter parameters of the object-side and image-side surfaces of the third spacer element can be reasonably controlled. This allows for reasonable control of the assembly step difference of the air gap between the third and fourth lenses, resulting in better assembly stability. Simultaneously, in conjunction with the control of the radius of curvature of the fourth lens, the emitted light rays can be well constrained, obtaining an image size that matches the design, thereby increasing pixel count and facilitating the miniaturization of the optical imaging system.

[0043] In an exemplary embodiment, the spacer element may further include a first spacer element, which is located between the first lens and the second lens and in direct contact with the image-side surface of the first lens. The optical imaging system according to this application satisfies: 0.5 < (T12 * ∑AT) / (CP1 * L) < 1.0. Wherein, T12 is the air gap between the first lens and the second lens on the optical axis, ∑AT is the sum of the air gaps on the optical axis between any two adjacent lenses with optical power from the first lens to the lens closest to the imaging surface, CP1 is the maximum thickness of the first spacer element, and L is the maximum height of the lens barrel. By setting a first spacer element between the first lens and the second lens, and satisfying the condition 0.5 < (T12*∑AT) / (CP1*L) < 1.0, the air gap between the first lens and the second lens on the optical axis and the total air gap of all adjacent lenses can be controlled. This effectively controls the axial height of the lens barrel, making it more compact in shape. At the same time, the maximum thickness of the first spacer element can enhance the stability of the air gap between the first lens and the second lens, thereby reducing the impact of gap changes on field curvature. Furthermore, by reasonably designing the maximum height of the lens barrel, the front and rear ends of the lens will not protrude and be scratched.

[0044] In an exemplary embodiment, the optical imaging system according to this application satisfies: 113.0 < f1*CT1 / (EP01*CP1) < 336.0. Where f1 is the effective focal length of the first lens, CT1 is the center thickness of the first lens on the optical axis, EP01 is the spacing between the front end face of the lens barrel and the first spacer element, and CP1 is the maximum thickness of the first spacer element. By satisfying 113.0 < f1*CT1 / (EP01*CP1) < 336.0, the effective focal length and center thickness of the first lens are reasonably controlled, which is more conducive to the shaping of the first lens, less prone to shrinkage marks, and avoids the generation of oblique stray light. Simultaneously, the maximum thickness design of the first spacer element increases the amount of incident light, thereby obtaining a larger aperture and improving the overall brightness of the image.

[0045] In an exemplary embodiment, the optical imaging system according to this application satisfies: 0.5 < f*(D0s-d0s) / (f1*(D1s-d1s)) < 3.0. Where f is the effective focal length of the optical imaging system, D0s is the outer diameter of the front face of the lens barrel closest to the object side, d0s is the inner diameter of the front face of the lens barrel closest to the object side, D1s is the outer diameter of the object side of the first spacer element, d1s is the inner diameter of the object side of the first spacer element, and f1 is the effective focal length of the first lens. By satisfying 0.5 < f*(D0s-d0s) / (f1*(D1s-d1s)) < 3.0, the effective focal length of the optical imaging system can be controlled, effectively controlling the image plane position, thereby keeping the module height within the design range. Simultaneously, controlling the inner and outer diameters of the front face of the lens barrel and the inner and outer diameters of the first spacer element allows for a larger assembly support space on the lens top surface, which is beneficial for improving assembly stability. Furthermore, in conjunction with the effective focal length design of the first lens, the lens can obtain a larger field of view, improving application performance.

[0046] In an exemplary embodiment, the optical imaging system according to this application satisfies: 1.0 < |R1+R2| / (d1s+d1m) < 5.0. Wherein, R1 is the radius of curvature of the object-side surface of the first lens, 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 element, and d1m is the inner diameter of the image-side surface of the first spacer element. By satisfying 1.0 < |R1+R2| / (d1s+d1m) < 5.0, the radii of curvature of the object-side and image-side surfaces of the first lens are reasonably controlled, resulting in a smoother curvature, which is beneficial for image formation. Simultaneously, in conjunction with the inner diameters of the object-side and image-side surfaces of the first spacer element, the amount of incident light can be effectively controlled, reducing the entry of invalid edge light rays, preventing stray light spots, and improving image quality.

[0047] In an exemplary embodiment, the spacer element may further include a second spacer element, which is located between the second lens and the third lens and directly contacts the image-side surface of the second lens. The optical imaging system according to this application satisfies: 2.5 < |f2*EP12| / (CP2*T23) < 6.0. Where f2 is the effective focal length of the second lens, EP12 is the gap between the first and second spacer elements, CP2 is the maximum thickness of the second spacer element, and T23 is the air gap between the second and third lenses on the optical axis. By satisfying 2.5 < |f2*EP12| / (CP2*T23) < 6.0, controlling the effective focal length of the second lens and the gap between the first and second spacer elements allows the edge thickness data of the second lens to be within the design range, resulting in better lens thickness-to-weight ratio data, which is beneficial for lens forming. Simultaneously, by combining the maximum thickness of the second spacer element and the gap between the first and second spacer elements, the system sensitivity at this air gap can be effectively reduced, resulting in a more stable imaging system.

[0048] In an exemplary embodiment, the optical imaging system according to this application satisfies: 14.0 < f12 / (d2m-d2s) < 17.0. Here, f12 is the combined focal length of the first and second lenses, d2m is the inner diameter of the image-side surface of the second spacer element, and d2s is the inner diameter of the object-side surface of the second spacer element. By satisfying 14.0 < f12 / (d2m-d2s) < 17.0, the effective focal lengths of the first and second lenses are reasonably controlled, effectively controlling the light focusing position. Simultaneously, by combining this with the inner diameter data of the image-side and object-side surfaces of the second spacer element, the light-gathering ability is improved, and the overall optical length is shortened, thereby achieving the design objective and requirement of miniaturization.

[0049] In an exemplary embodiment, the optical imaging system according to this application satisfies: -27.0 < (R3 + R4) / (CP2 + CT2 + EP23) < -1.0. Here, R3 is the radius of curvature of the object-side surface of the second lens, R4 is the radius of curvature of the image-side surface of the second lens, CT2 is the center thickness of the second lens on the optical axis, CP2 is the maximum thickness of the second spacer element, and EP23 is the spacing between the second and third spacers. By satisfying -27.0 < (R3 + R4) / (CP2 + CT2 + EP23) < -1.0, controlling the radii of curvature of the object-side and image-side surfaces of the second lens avoids excessive bending of the second lens, reducing manufacturing difficulty. Furthermore, by combining parameters such as the center thickness of the second lens and the maximum thickness of the second spacer element, the optical lens can achieve better balance between chromatic aberration and distortion.

[0050] In an exemplary embodiment, the optical imaging system according to this application satisfies: 0.5 < |R5*CT3| / (CP2*(D2m+d2m)) < 1.5. Here, R5 is the radius of curvature of the object-side surface of the third lens, CT3 is the center thickness of the third lens along the optical axis, CP2 is the maximum thickness of the second spacer element, D2m is the outer diameter of the image-side surface of the second spacer element, and d2m is the inner diameter of the image-side surface of the second spacer element. By satisfying 0.5 < |R5*CT3| / (CP2*(D2m+d2m)) < 1.5, controlling the radius of curvature and center thickness of the third lens allows the aspherical lens thickness ratio to fall within a more easily processed range. Simultaneously, in conjunction with the maximum thickness and inner / outer diameter parameters of the second spacer element, field curvature sensitivity can be effectively improved, while absorbing excess edge stray light and improving image clarity.

[0051] In an exemplary embodiment, the optical imaging system according to this application satisfies: 0.0 < (f3 + f4) / (D3s - D2m) < 1.0. Here, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, D3s is the outer diameter of the object-side surface of the third spacer element, and D2m is the outer diameter of the image-side surface of the second spacer element. By satisfying 0.0 < (f3 + f4) / (D3s - D2m) < 1.0, the effective focal lengths of the third and fourth lenses are controlled, allowing for a reasonable allocation of the optical power of the optical imaging system, thus canceling out the positive and negative spherical aberrations generated by the front and rear lenses. Simultaneously, controlling the outer diameter parameters of the second and third spacers allows for a controllable gradient in the lens outer diameter distribution, reducing step differences and improving assembly stability.

[0052] In an exemplary embodiment, the optical imaging system according to this application satisfies: 5.5 < f34 / (CP3+EP23+CT3+T34) < 12.5. Here, f34 is the combined focal length of the third and fourth lenses, CP3 is the maximum thickness of the third spacer element, EP23 is the spacing between the second and third spacers, CT3 is the center thickness of the third lens on the optical axis, and T34 is the air gap between the third and fourth lenses on the optical axis. By satisfying 5.5 < f34 / (CP3+EP23+CT3+T34) < 12.5, controlling the combined focal length of the third and fourth lenses effectively controls the system's astigmatism. Simultaneously, it effectively shortens the focal length of the optical system, making its axial height controllable. Furthermore, by considering the thickness of the third spacer element, the thickness of the third lens, and the relevant parameters of the air gaps before and after it, it effectively improves the field curvature sensitivity, making its change proportional to the change in field curvature, thus facilitating subsequent MTF (Modulation Transfer Function) yield improvement.

[0053] In an exemplary embodiment, the optical imaging system according to this application satisfies: 1.5 < |f4*R7| / (d3s*CP3) < 3.5. Here, f4 is the effective focal length of the fourth lens, R7 is the radius of curvature of the object-side surface of the fourth lens, d3s is the inner diameter of the object-side surface of the third spacer element between the third and fourth lenses and in direct contact with the image-side surface of the third lens, and CP3 is the maximum thickness of the third spacer element between the third and fourth lenses and in direct contact with the image-side surface of the third lens. By satisfying 1.5 < |f4*R7| / (d3s*CP3) < 3.5, the effective focal length of the fourth lens and the radius of curvature of its object-side surface are controlled, effectively controlling the degree of curvature of the fourth lens, which is beneficial for processing and shaping. Simultaneously, in conjunction with the inner diameter and maximum thickness of the object-side surface of the third spacer element, the angle of the emitted light rays can be effectively controlled, obtaining the desired image size and reducing stray light generation.

[0054] In an exemplary embodiment, the optical imaging system according to this application satisfies: 1.0 < TAN(Semi-FOV)*f / (D0m-D3m) < 2.0. Wherein, Semi-FOV is half of the maximum field of view of the optical imaging system, f is the effective focal length of the optical imaging system, D0m is the outer diameter of the rear end face of the lens barrel closest to the imaging plane, and D3m is the outer diameter of the image-side surface of the third spacer element. By satisfying 1.0 < TAN(Semi-FOV)*f / (D0m-D3m) < 2.0, controlling the parameters of half of the maximum field of view of the imaging lens and the effective focal length of the optical system allows for a wider field of view to be captured. Simultaneously, the effective focal length shortens the distance between the lens and the image plane, reducing the module size. Furthermore, by controlling the rear end diameter of the lens barrel and the outer diameter of the image-side surface of the third spacer element, the parameters of the printing position at the rear end of the lens barrel and the fixed position of the module can be ensured to be within the target range, improving reliability.

[0055] In an exemplary embodiment, the optical imaging system according to this application satisfies: 2.5 < f23 / (EP12+EP23) < 6.5. Here, f23 is the combined focal length of the second and third lenses, EP12 is the spacing between the first and second spacers, and EP23 is the spacing between the second and third spacers. By satisfying 2.5 < f23 / (EP12+EP23) < 6.5, the combined focal length of the second and third lenses is reasonably controlled, effectively correcting distortion in the paraxial range of the image plane, thereby improving the imaging quality of the system. Simultaneously, by coordinating the distances between the first and second spacers and between the second and third spacers, the edge thickness data of the second and third lenses can be effectively controlled, resulting in better reliability performance in assembly pressure simulations.

[0056] In an exemplary embodiment, the optical imaging system according to this application satisfies: 2.5 < |R5 + R6| / (EP12 + CP2 + T23) < 5.0. Here, R5 is the radius of curvature of the object-side surface of the third lens, R6 is the radius of curvature of the image-side surface of the third lens, EP12 is the spacing between the first and second spacers, CP2 is the maximum thickness of the second spacer, and T23 is the air gap between the second and third lenses on the optical axis. By satisfying 2.5 < |R5 + R6| / (EP12 + CP2 + T23) < 5.0, controlling the radius of curvature parameter of the third lens allows for better control of the lens curvature, reducing residual molding stress. Simultaneously, by coordinating the distance parameters between the first and second spacers, the thickness parameters of the second spacer, and the spacing parameters between the first and second spacers, the light convergence in front of the third lens can be effectively controlled. Furthermore, the third lens enables a more ideal light emission angle and light quantity, improving the overall brightness of the system and thus enhancing image quality.

[0057] In an exemplary embodiment, the effective focal length f1 of the first lens may be in the range of 2.56 mm to 3.04 mm, the effective focal length f2 of the second lens may be in the range of -4.73 mm to -3.39 mm, the effective focal length f3 of the third lens may be in the range of 2.85 mm to 3.36 mm, and the effective focal length f4 of the fourth lens may be in the range of -2.86 mm to -2.64 mm.

[0058] In an exemplary embodiment, the outer diameter D1s of the object side of the first spacer element can be, for example, in the range of 2.0 mm to 4.0 mm; the outer diameter D1m of the image side of the first spacer element can be, for example, in the range of 2.0 mm to 4.0 mm; the inner diameters d1s and d1m of both the object side and image side of the first spacer element can be, for example, in the range of 1.5 mm to 2.5 mm; the outer diameter D2s of the object side of the second spacer element can be, for example, in the range of 3.0 mm to 4.5 mm; the outer diameter D2m of the image side of the second spacer element can be, for example, in the range of 3.5 mm to 4.5 mm; the inner diameters d2s and d2m of both the object side and image side of the second spacer element can be, for example, in the range of 2.0 mm to 3.5 mm; the outer diameter D3s of the object side of the third spacer element can be, for example, in the range of 4.0 mm to 5.0 mm; and the outer diameter of the object side of the third spacer element... The outer diameter D3m of the image side can be, for example, in the range of 4.0 mm to 5.5 mm; the inner diameter d3s of the object side of the third spacer can be, for example, in the range of 2.5 mm to 3.5 mm; the inner diameter d3m of the image side of the third spacer can be, for example, in the range of 3.0 mm to 4.0 mm; the spacing EP12 between the first spacer and the second spacer can be, for example, in the range of 0.6 mm to 0.8 mm; the spacing EP23 between the second spacer and the third spacer can be, for example, in the range of 0.4 mm to 0.6 mm; the maximum thickness CP1 of the first spacer can be, for example, in the range of 0.01 mm to 0.02 mm; the maximum thickness CP2 of the second spacer can be, for example, in the range of 0.6 mm to 0.9 mm; and the maximum thickness CP3 of the third spacer can be, for example, in the range of 0.4 mm to 0.8 mm.

[0059] It should be understood that this application does not specifically limit the number of spacers; any number of spacers may be included between any two lenses, and the entire optical imaging system may also include any number of spacers. Spacers help the optical imaging system intercept excess reflective light paths, reducing stray light and ghosting. Adding auxiliary support between the spacers and the lens barrel helps improve problems such as poor assembly stability and low performance yield caused by large step differences between lenses.

[0060] In some embodiments, the optical imaging system according to this application may further include a filter and / or protective glass disposed between the fourth lens and the imaging surface, for filtering light of different wavelengths, correcting color deviations, and protecting the photosensitive element located on the imaging surface.

[0061] In some embodiments, the optical imaging system according to this application may further include an aperture stop disposed between the object side and the first lens. The placement of the aperture stop facilitates the effective focusing of light entering the optical lens and helps to reduce the aperture of the lens.

[0062] According to the optical imaging system of the above embodiments of this application, its lens group can adopt multiple lenses, such as the four lenses described above. By reasonably allocating the focal length, surface shape, center thickness of each lens, and on-axis spacing between each lens, incident light rays can be effectively converged, the total optical length can be reduced, and manufacturability can be improved, making the optical imaging system more conducive to production and processing.

[0063] In embodiments of this application, at least one of the mirror surfaces of the first to fourth lenses is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike a spherical lens, which has a constant curvature from its center to its periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. Optionally, both the object-side and image-side surfaces of each of the first to fourth lenses are aspherical mirror surfaces.

[0064] However, those skilled in the art will understand that the number of lenses constituting the optical imaging system 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 system is not limited to including four lenses. If desired, the optical imaging system may also include other numbers of lenses.

[0065] Embodiments 1 to 4 of the optical imaging system applicable to the above exemplary embodiments are further described below with reference to the accompanying drawings. Figure 2 Schematic diagrams illustrating the elimination of stray light in the optical imaging systems of Embodiments 1 to 4 according to this application are shown. Figure 2 As shown, stray light enters the lens from the object side and exits from the image side. The third spacer element, located between the third and fourth lenses and in direct contact with the image side of the third lens, effectively blocks stray light at the edge of the third lens. Furthermore, by rationally controlling the outer diameter parameters of the object and image sides of the third spacer element, the assembly step difference of the air gap between the third and fourth lenses can be rationally controlled, resulting in superior assembly stability. Simultaneously, in conjunction with the control of the curvature radius of the fourth lens, the outgoing light rays can be well constrained, significantly reducing the reflected light path at this location, thereby obtaining an image size that matches the design, increasing pixel count, and facilitating miniaturization.

[0066] Example 1

[0067] The following is for reference Figures 3A to 4D An optical imaging system according to Embodiment 1 of this application is described. Embodiment 1 includes Embodiment 1-1 and Embodiment 1-2. Figure 3Aand Figure 3B Schematic diagrams of the optical imaging systems according to Embodiments 1-1 and 1-2 of this application are shown respectively.

[0068] like Figure 3A and Figure 3B As shown, the optical imaging system includes a lens barrel P0, a lens group, and at least one spacer element. The lens group, from the object side to the image side, includes, in sequence: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter, and an imaging surface (not shown in the figure).

[0069] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being convex. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The filter E5 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] Table 1 shows the basic parameters of the optical imaging system of Example 1-1 / Example 1-2, where the units for radius of curvature, thickness / distance and focal length are millimeters (mm).

[0071]

[0072] Table 1

[0073] In this embodiment, the effective focal length f of the optical imaging system is 4.20 mm, the focal length f1 of the first lens is 2.56 mm, the focal length f2 of the second lens is -3.39 mm, the focal length f3 of the third lens is 3.36 mm, and the focal length f4 of the fourth lens is -2.86 mm; the combined focal length f12 of the first and second lenses is 6.21 mm, the combined focal length f23 of the second and third lenses is 7.01 mm, the combined focal length f34 of the third and fourth lenses is 21.67 mm, and half of the maximum field of view (Semi-FOV) of the optical imaging system is 24.82°.

[0074] like Figure 3A and Figure 3BAs shown, in the optical imaging systems of Embodiments 1-1 and 1-2 of this application, the spacer element may include: a first spacer element P1 located between the first lens E1 and the second lens E2 and in direct contact with the image side of the first lens E1; a second spacer element P2 located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2; and a third spacer element P3 located between the third lens E3 and the fourth lens E4 and in direct contact with the image side of the third lens E3.

[0075] like Figure 3B As shown, in the optical imaging system of embodiments 1-2 of this application, the spacer element may further include a fourth spacer element P2b located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2.

[0076] In this embodiment, the first spacer element P1 and the fourth spacer element P2b are spacers with a thickness in the range of 0.01mm-0.02mm, while the second spacer element P2 and the third spacer element P3 are spacers or spacers with a certain thickness in the range of 0.6-0.9mm. Multiple spacers can block excess external light from entering, allowing the lens and lens barrel to better support each other and enhancing the structural stability of the imaging system.

[0077] In Example 1-1, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 3.43 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.21 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 5.58 mm; the outer diameter D1s of the object side of the first spacer element P1 is 3.38 mm; the inner diameters d1s and d1m of the object side and image side of the first spacer element P1 in the optical imaging system are both 1.57 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.63 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.12 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.5 mm. The image-side inner diameter d2m of the second spacer P2 is 2.50mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.67mm, the object-side outer diameter D3s of the third spacer P3 is 4.23mm, the object-side inner diameter d3s of the third spacer P3 is 2.74mm, the image-side outer diameter D3m of the third spacer P3 is 4.35mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.45mm, the maximum thickness CP1 of the first spacer P1 is 0.02mm, the maximum thickness CP2 of the second spacer P2 is 0.82mm, the maximum thickness CP3 of the third spacer P3 is 0.69mm, and the maximum height L of the lens barrel P0 is 4.28mm.

[0078] In embodiments 1-2, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 3.85 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.48 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 5.69 mm; the outer diameter D1s of the object side of the first spacer element P1 is 2.49 mm; the inner diameters d1s and d1m of the object side of the first spacer element P1 in the optical imaging system are both 1.64 mm; the distance EP01 between the front end face of the lens barrel P0 closest to the object side and the first spacer element P1 along the optical axis is 0.63 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.23 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.6 mm. The lens barrel has the following dimensions: 7mm, the inner diameter d2m of the image side of the second spacer P2 is 2.61mm, the spacing EP12 between the first spacer P1 and the second spacer P2 is 0.66mm, the outer diameter D3s of the object side of the third spacer P3 is 4.34mm, the inner diameter d3s of the object side of the third spacer P3 is 2.85mm, the outer diameter D3m of the image side of the third spacer P3 is 4.51mm, the spacing EP23 between the second spacer P2 and the third spacer P3 is 0.47mm, the maximum thickness CP1 of the first spacer P1 is 0.02mm, the maximum thickness CP2 of the second spacer P2 is 0.80mm, the maximum thickness CP3 of the third spacer P3 is 0.64mm, and the maximum height L of the lens barrel P0 is 4.28mm.

[0079] 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 surfaces, and the surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0080]

[0081] 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, A1, A2, A3, A4, A5, A6, A8, A1, A1, A2, A3, A4, A5, A6, A1, A2, A3, A4, A5, A6, A7, A8, A1, A1, A1, A1, A2, A1 ... 10 A 12 A 14 A 16 A 18 A 20 A 22 A 24 A 26 A 28 and A30 .

[0082] Face number A4 A6 A8 A10 A12 A14 A16 S1 -3.9870E-03 2.3564E-03 4.0448E-04 2.3573E-04 -1.5987E-05 3.5385E-05 -6.0803E-06 S2 3.8705E-02 2.9459E-03 8.4173E-04 9.1058E-05 5.6478E-05 -3.3474E-06 3.7318E-05 S3 1.5117E-02 -1.0775E-03 3.4828E-04 -1.1114E-04 5.0043E-05 -3.0983E-05 5.4236E-05 S4 9.5736E-03 2.8016E-04 -4.3197E-04 1.9211E-04 -9.5982E-05 5.4726E-05 -4.1302E-05 S5 9.3562E-02 2.2231E-02 -7.8048E-04 5.4757E-04 -1.9656E-04 1.6053E-04 7.2440E-06 S6 1.8545E-01 3.1113E-02 5.9787E-03 1.4422E-03 1.3277E-04 -2.0978E-05 1.2166E-04 S7 2.4265E-01 -8.0065E-03 2.1040E-02 1.4963E-03 2.0815E-03 -1.1791E-03 7.8755E-04 S8 -1.8302E-01 -5.8392E-02 2.4546E-02 -5.0499E-03 2.3232E-03 -3.3988E-03 9.4138E-04

[0083] Table 2-1

[0084] Face number A18 A20 A22 A24 A26 A28 A30 S1 2.3689E-05 2.5220E-06 2.2382E-05 1.1795E-05 1.5166E-05 7.7263E-06 1.0796E-05 S2 -8.2097E-06 -4.2718E-06 -1.1772E-05 6.7294E-07 5.9309E-06 9.0101E-06 -6.0284E-06 S3 2.8056E-07 2.0768E-05 4.4227E-06 1.7822E-05 7.3240E-06 5.0581E-06 -9.0544E-06 S4 1.3207E-05 -1.6779E-05 -7.3348E-07 -1.1689E-05 -1.3259E-06 -2.0596E-06 1.2726E-06 S5 -4.0048E-06 -2.4493E-05 1.5429E-05 1.7351E-06 1.9524E-05 1.2859E-08 -1.4616E-05 S6 6.7076E-05 1.7228E-05 -2.9712E-06 1.9142E-05 -7.1917E-06 -2.2043E-05 -1.2841E-05 S7 -2.4114E-04 5.3649E-04 -3.5126E-04 1.9052E-04 -2.6918E-04 -1.8826E-05 2.2288E-05 S8 -1.0065E-03 1.0995E-03 -4.8694E-04 8.7880E-04 -4.4603E-04 2.9504E-04 -1.0405E-04

[0085] Table 2-2

[0086] Figure 4A The on-axis chromatic aberration curves of the optical imaging systems 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 4B Astigmatism curves of the optical imaging systems of Embodiment 1-1 / Embodiment 1-2 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 4C The distortion curves of the optical imaging systems of Embodiment 1-1 / Embodiment 1-2 are shown, representing the distortion magnitude values ​​corresponding to different image heights. Figure 4D The magnification chromatic aberration curves of the optical imaging systems 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 4A to 4D It can be seen that the optical imaging system given in Example 1-1 / Example 1-2 can achieve good imaging quality.

[0087] Example 2

[0088] The following is for reference Figures 5A to 6D An optical imaging system according to Embodiment 2 of this application is described. Embodiment 2 includes Embodiment 2-1 and Embodiment 2-2. Figure 5A and Figure 5B Schematic diagrams of the optical imaging systems according to Embodiments 2-1 and 2-2 of this application are shown respectively.

[0089] like Figure 5A and Figure 5B As shown, the optical imaging system includes a lens barrel P0, a lens group, and at least one spacer element. The lens group, from the object side to the image side, includes, in sequence: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter, and an imaging surface (not shown in the figure).

[0090] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being convex. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The filter E5 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.

[0091] Table 3 shows the basic parameters of the optical imaging system of Example 2-1 / Example 2-2, where the units for radius of curvature, thickness / distance and focal length are millimeters (mm).

[0092]

[0093] Table 3

[0094] In this embodiment, the effective focal length f of the optical imaging system is 4.09 mm, the focal length f1 of the first lens is 2.97 mm, the focal length f2 of the second lens is -5.03 mm, the focal length f3 of the third lens is 3.29 mm, and the focal length f4 of the fourth lens is -2.83 mm; the combined focal length f12 of the first and second lenses is 5.50 mm, the combined focal length f23 of the second and third lenses is 5.05 mm, the combined focal length f34 of the third and fourth lenses is 32.80 mm, and half of the maximum field of view (Semi-FOV) of the optical imaging system is 25.32°.

[0095] like Figure 5A and Figure 5B As shown, in the optical imaging systems of Embodiments 2-1 and 2-2 of this application, the spacer element may include: a first spacer element P1 located between the first lens E1 and the second lens E2 and in direct contact with the image side of the first lens E1; a second spacer element P2 located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2; and a third spacer element P3 located between the third lens E3 and the fourth lens E4 and in direct contact with the image side of the third lens E3.

[0096] like Figure 5B As shown, in the optical imaging system of Embodiment 2-2 of this application, the spacer element may further include a fourth spacer element P2b located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2.

[0097] In this embodiment, the first spacer element P1 and the fourth spacer element P2b are spacers with a thickness in the range of 0.01mm-0.02mm, while the second spacer element P2 and the third spacer element P3 are spacers or spacers with a thickness in the range of 0.6mm-0.8mm. Multiple spacers can block excess external light from entering, allowing the lens and lens barrel to better support each other and enhancing the structural stability of the imaging system.

[0098] In Example 2-1, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 3.40 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.18 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 5.55 mm; the outer diameter D1s of the object side of the first spacer element P1 is 3.35 mm; the inner diameters d1s and d1m of the object side and image side of the first spacer element P1 in the optical imaging system are both 1.54 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.63 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.08 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.5 mm. The image-side inner diameter d2m of the second spacer P2 is 2.47mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.67mm, the object-side outer diameter D3s of the third spacer P3 is 4.03mm, the object-side inner diameter d3s of the third spacer P3 is 2.70mm, the image-side outer diameter D3m of the third spacer P3 is 4.41mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.48mm, the maximum thickness CP1 of the first spacer P1 is 0.02mm, the maximum thickness CP2 of the second spacer P2 is 0.68mm, the maximum thickness CP3 of the third spacer P3 is 0.71mm, and the maximum height L of the lens barrel P0 is 4.28mm.

[0099] In Example 2-2, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 3.82 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.45 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 5.66 mm; the outer diameter D1s of the object side of the first spacer element P1 is 2.45 mm; the inner diameters d1s and d1m of the object side and image side of the first spacer element P1 in the optical imaging system are both 1.61 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.64 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.20 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.7 mm. The image-side inner diameter d2m of the second spacer P2 is 2.58mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.64mm, the object-side outer diameter D3s of the third spacer P3 is 4.23mm, the object-side inner diameter d3s of the third spacer P3 is 2.82mm, the image-side outer diameter D3m of the third spacer P3 is 4.48mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.55mm, the maximum thickness CP1 of the first spacer P1 is 0.02mm, the maximum thickness CP2 of the second spacer P2 is 0.69mm, the maximum thickness CP3 of the third spacer P3 is 0.69mm, and the maximum height L of the lens barrel P0 is 4.34mm.

[0100] In Examples 2-1 and 2-2, the object-side and image-side surfaces of any one of the first lens E1 to the fourth lens E4 are aspherical, and the surface shape x of each aspherical lens can be defined using formula (1) given in Example 1 above. Tables 4-1 and 4-2 below give the higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror S1-S8 in Example 1. 10 A 12 A 14 A 16 A 18 A 20 A 22 A 24 A 26 A 28 and A 30 .

[0101]

[0102]

[0103] Table 4-1

[0104] Face number A18 A20 A22 A24 A26 A28 A30 S1 -6.3462E-06 -7.5610E-06 7.5156E-06 6.1521E-06 1.0594E-05 3.9385E-06 2.5920E-06 S2 -5.1212E-05 -3.6537E-05 -6.5418E-05 -5.1140E-05 -4.8880E-05 -2.3174E-05 -1.4811E-05 S3 2.0810E-05 3.6976E-05 1.6172E-05 1.3231E-05 -2.0856E-06 6.8200E-07 -1.7853E-06 S4 2.6253E-06 -3.5962E-06 -2.4267E-07 -2.2794E-06 4.2872E-07 5.3505E-07 9.6180E-07 S5 4.6842E-05 -1.0716E-05 1.6080E-05 -1.0898E-05 7.9445E-06 -4.2355E-06 4.2943E-06 S6 -3.2644E-05 -2.6138E-05 -4.1489E-05 -1.0949E-05 -1.8449E-05 9.5005E-07 -7.0011E-06 S7 -8.8854E-05 -3.0329E-05 -3.1420E-05 8.8409E-07 -2.8698E-05 -9.9052E-06 -3.6516E-06 S8 -1.9131E-04 7.3293E-05 -5.8510E-05 2.1346E-05 -3.6682E-05 2.0314E-05 -2.4088E-05

[0105] Table 4-2

[0106] Figure 6A The on-axis chromatic aberration curves of the optical imaging systems of Embodiment 2-1 / 2-2 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 6B Astigmatism curves of the optical imaging systems of Embodiment 2-1 / 2-2 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 6C The distortion curves of the optical imaging system of Embodiment 2-1 / Embodiment 2-2 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 6D The magnification chromatic aberration curves of the optical imaging systems of Embodiment 2-1 / 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 6A to 6D It can be seen that the optical imaging system given in Example 2-1 / Example 2-2 can achieve good imaging quality.

[0107] Example 3

[0108] The following is for reference Figures 7A to 8D An optical imaging system according to Embodiment 3 of this application is described. Embodiment 3 includes Embodiment 3-1 and Embodiment 3-2. Figure 7A and Figure 7B Schematic diagrams of the optical imaging systems according to Embodiments 3-1 and 3-2 of this application are shown respectively.

[0109] like Figure 7A and Figure 7B As shown, the optical imaging system includes a lens barrel P0, a lens group, and at least one spacer element. The lens group, from the object side to the image side, includes, in sequence: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter, and an imaging surface (not shown in the figure).

[0110] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being convex. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The filter E5 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.

[0111] Table 5 shows the basic parameters of the optical imaging system of Example 3-1 / Example 3-2, where the units for radius of curvature, thickness / distance and focal length are millimeters (mm).

[0112]

[0113]

[0114] Table 5

[0115] In this embodiment, the effective focal length f of the optical imaging system is 4.36 mm, the focal length f1 of the first lens is 2.83 mm, the focal length f2 of the second lens is -4.26 mm, the focal length f3 of the third lens is 2.85 mm, and the focal length f4 of the fourth lens is -2.77 mm; the combined focal length f12 of the first and second lenses is 6.15 mm, the combined focal length f23 of the second and third lenses is 3.80 mm, the combined focal length f34 of the third and fourth lenses is 15.80 mm, and half of the maximum field of view (Semi-FOV) of the optical imaging system is 24.10°.

[0116] like Figure 7A and Figure 7B As shown, in the optical imaging systems of Embodiments 3-1 and 3-2 of this application, the spacer element may include: a first spacer element P1 located between the first lens E1 and the second lens E2 and in direct contact with the image side of the first lens E1; a second spacer element P2 located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2; and a third spacer element P3 located between the third lens E3 and the fourth lens E4 and in direct contact with the image side of the third lens E3.

[0117] like Figure 7B As shown, in the optical imaging system of Embodiment 3-2 of this application, the spacer element may further include a fourth spacer element P2b located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2.

[0118] In this embodiment, the first spacer element P1 and the fourth spacer element P2b are spacers with a thickness in the range of 0.01mm-0.02mm, while the second spacer element P2 and the third spacer element P3 are spacers or spacers with a thickness in the range of 0.5mm-0.8mm. Multiple spacers can block excess external light from entering, allowing the lens and lens barrel to better support each other and enhancing the structural stability of the imaging system.

[0119] In Example 3-1, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 3.56 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.34 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 5.71 mm; the outer diameter D1s of the object side of the first spacer element P1 is 3.51 mm; the inner diameters d1s and d1m of the object side of the first spacer element P1 in the optical imaging system are both 1.70 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.65 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.25 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.6 mm. The image-side inner diameter d2m of the second spacer P2 is 2.63mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.71mm, the object-side outer diameter D3s of the third spacer P3 is 4.40mm, the object-side inner diameter d3s of the third spacer P3 is 2.87mm, the image-side outer diameter D3m of the third spacer P3 is 4.57mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.48mm, the maximum thickness CP1 of the first spacer P1 is 0.01mm, the maximum thickness CP2 of the second spacer P2 is 0.77mm, the maximum thickness CP3 of the third spacer P3 is 0.57mm, and the maximum height L of the lens barrel P0 is 4.91mm.

[0120] In Example 3-2, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 4.03 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.66 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 5.87 mm; the outer diameter D1s of the object side of the first spacer element P1 is 2.66 mm; the inner diameters d1s and d1m of the object side and image side of the first spacer element P1 in the optical imaging system are both 1.82 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.64 mm; the inner diameter d2s of the object side of the second spacer element P2 is 241 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.84 mm. The inner diameter d2m of the image side of the second spacer P2 is 2.79 mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.70 mm, the outer diameter D3s of the object side of the third spacer P3 is 4.66 mm, the inner diameter d3s of the object side of the third spacer P3 is 3.02 mm, the outer diameter D3m of the image side of the third spacer P3 is 4.68 mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.55 mm, the maximum thickness CP1 of the first spacer P1 is 0.02 mm, the maximum thickness CP2 of the second spacer P2 is 0.78 mm, the maximum thickness CP3 of the third spacer P3 is 0.54 mm, and the maximum height L of the lens barrel P0 is 4.90 mm.

[0121] In Examples 3-1 and 3-2, the object-side and image-side surfaces of any one of the first lens E1 to the fourth lens E4 are aspherical, and the surface shape x of each aspherical lens can be defined using formula (1) given in Example 1 above. Tables 6-1 and 6-2 below give the higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror S1-S8 in Example 1. 10 A 12 A 14 A 16 A 18 A 20 A 22 A 24 A 26 A 28 and A 30 .

[0122] Face number A4 A6 A8 A10 A12 A14 A16 S1 -8.3234E-04 2.7104E-03 5.0550E-04 9.8299E-05 -5.6890E-05 -3.2956E-05 -4.7577E-05 S2 4.9236E-02 4.9570E-03 1.1499E-03 1.4746E-04 5.3321E-05 -2.9174E-05 -2.1984E-06 S3 1.7113E-02 -6.6811E-04 9.1617E-05 1.0267E-05 1.8127E-05 -1.1176E-05 -8.6230E-06 S4 2.6635E-02 -1.0045E-03 -1.1687E-04 8.7751E-05 -6.2158E-06 3.5675E-05 3.8972E-06 S5 6.7186E-02 1.5109E-02 2.6256E-03 1.5159E-03 -1.1383E-06 -5.3492E-05 0.0000E+00 S6 3.2764E-01 4.2850E-02 1.6542E-02 6.3452E-03 2.5535E-03 8.5939E-04 4.2054E-04 S7 4.5499E-01 2.4976E-02 3.4029E-02 1.3365E-02 7.1839E-03 3.4824E-03 1.8153E-03 S8 6.4075E-02 -8.9269E-02 1.7313E-02 -1.8929E-03 1.3931E-03 -4.9720E-05 1.2881E-04

[0123] Table 6-1

[0124] Face number A18 A20 A22 A24 A26 A28 A30 S1 -2.1077E-05 -2.4621E-05 -1.2832E-05 -1.2020E-05 -5.4375E-06 -4.8942E-06 1.8814E-06 S2 -1.3315E-05 6.9206E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -1.3562E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 1.1815E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 1.1644E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 8.3115E-04 3.3248E-04 5.1593E-05 6.8747E-05 2.7027E-04 1.0528E-03 1.2984E-03 S8 1.2627E-05 4.2231E-05 -7.8028E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0125] Table 6-2

[0126] Figure 8A The on-axis chromatic aberration curves of the optical imaging systems 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 8B Astigmatism curves of the optical imaging systems of Embodiment 3-1 / Embodiment 3-2 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 8C The distortion curves of the optical imaging systems of Embodiment 3-1 / Embodiment 3-2 are shown, representing the distortion magnitude values ​​corresponding to different image heights. Figure 8D The magnification chromatic aberration curves of the optical imaging systems of Embodiment 3-1 / 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 8A to 8D It can be seen that the optical imaging system given in Example 3-1 / Example 3-2 can achieve good imaging quality.

[0127] Example 4

[0128] The following is for reference Figures 9A to 10D An optical imaging system according to Embodiment 4 of this application is described. Embodiment 4 includes Embodiment 4-1 and Embodiment 4-2. Figure 9A and Figure 9B Schematic diagrams of the optical imaging systems according to Embodiments 4-1 and 4-2 of this application are shown respectively.

[0129] like Figure 9A and Figure 9B As shown, the optical imaging system includes a lens barrel P0, a lens group, and at least one spacer element. The lens group, from the object side to the image side, includes, in sequence: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter, and an imaging surface (not shown in the figure).

[0130] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being convex. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being concave. The filter E5 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.

[0131] Table 7 shows the basic parameters of the optical imaging system of Example 4-1 / Example 4-2, where the units for radius of curvature, thickness / distance and focal length are millimeters (mm).

[0132]

[0133] Table 7

[0134] In this embodiment, the effective focal length f of the optical imaging system is 4.89 mm, the focal length f1 of the first lens is 3.04 mm, the focal length f2 of the second lens is -4.73 mm, the focal length f3 of the third lens is 2.85 mm, and the focal length f4 of the fourth lens is -2.64 mm; the combined focal length f12 of the first and second lenses is 6.31 mm, the combined focal length f23 of the second and third lenses is 3.58 mm, the combined focal length f34 of the third and fourth lenses is 28.68 mm, and half of the maximum field of view (Semi-FOV) of the optical imaging system is 21.61°.

[0135] like Figure 9A and Figure 9B As shown, in the optical imaging systems of Embodiments 4-1 and 4-2 of this application, the spacer element may include: a first spacer element P1 located between the first lens E1 and the second lens E2 and in direct contact with the image side of the first lens E1; a second spacer element P2 located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2; and a third spacer element P3 located between the third lens E3 and the fourth lens E4 and in direct contact with the image side of the third lens E3.

[0136] like Figure 9B As shown, in the optical imaging system of Embodiment 4-2 of this application, the spacer element may further include a fourth spacer element P2b located between the second lens E2 and the third lens E3 and in direct contact with the image side of the second lens E2.

[0137] In this embodiment, the first spacer element P1 and the fourth spacer element P2b are spacers with a thickness ranging from 0.01mm to 0.02mm, while the second spacer element P2 and the third spacer element P3 are spacers or spacers with a thickness ranging from 0.4mm to 0.9mm. Multiple spacers can block excess external light from entering, allowing the lens and lens barrel to better support each other and enhancing the structural stability of the imaging system.

[0138] In Example 4-1, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 3.93 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.71 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 6.08 mm; the outer diameter D1s of the object side of the first spacer element P1 is 3.88 mm; the inner diameters d1s and d1m of the object side of the first spacer element P1 in the optical imaging system are both 2.07 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.68 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.62 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 3.8 mm. The image-side inner diameter d2m of the second spacer P2 is 3.00mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.69mm, the object-side outer diameter D3s of the third spacer P3 is 4.92mm, the object-side inner diameter d3s of the third spacer P3 is 3.23mm, the image-side outer diameter D3m of the third spacer P3 is 4.94mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.48mm, the maximum thickness CP1 of the first spacer P1 is 0.01mm, the maximum thickness CP2 of the second spacer P2 is 0.88mm, the maximum thickness CP3 of the third spacer P3 is 0.45mm, and the maximum height L of the lens barrel P0 is 5.56mm.

[0139] In Example 4-2, the outer diameter D0s of the front end face of the lens barrel P0 closest to the object side is 4.30 mm; the inner diameter d0s of the front end face of the lens barrel P0 closest to the object side is 2.92 mm; the outer diameter D0m of the rear end face of the lens barrel P0 closest to the image plane is 6.13 mm; the outer diameter D1s of the object side of the first spacer element P1 is 2.93 mm; the inner diameters d1s and d1m of the object side of the first spacer element P1 in the optical imaging system are both 2.09 mm; the distance EP01 between the front end face of the lens barrel P0 and the first spacer element P1 along the optical axis is 0.66 mm; the inner diameter d2s of the object side of the second spacer element P2 is 2.67 mm; and the outer diameter D2m of the image side of the second spacer element P2 is 4.0 mm. The image-side inner diameter d2m of the second spacer P2 is 3.06mm, the gap EP12 between the first spacer P1 and the second spacer P2 is 0.69mm, the object-side outer diameter D3s of the third spacer P3 is 4.92mm, the object-side inner diameter d3s of the third spacer P3 is 3.29mm, the image-side outer diameter D3m of the third spacer P3 is 5.01mm, the gap EP23 between the second spacer P2 and the third spacer P3 is 0.55mm, the maximum thickness CP1 of the first spacer P1 is 0.01mm, the maximum thickness CP2 of the second spacer P2 is 0.89mm, the maximum thickness CP3 of the third spacer P3 is 0.48mm, and the maximum height L of the lens barrel P0 is 5.55mm.

[0140] In Examples 4-1 and 4-2, the object-side and image-side surfaces of any one of the first lens E1 to the fourth lens E4 are aspherical, and the surface shape x of each aspherical lens can be defined using formula (1) given in Example 1 above. Tables 8-1 and 8-2 below give the higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror S1-S8 in Example 1. 10 A 12 A 14 A 16 A 18 A 20 A 22 A 24 A 26 A 28 and A 30 .

[0141] Face number A4 A6 A8 A10 A12 A14 A16 S1 -5.8751E-04 4.0914E-03 9.8152E-04 2.7783E-04 3.8603E-05 3.0699E-05 -3.4879E-06 S2 6.5441E-02 7.4536E-03 1.9979E-03 5.7993E-04 3.4873E-04 2.3346E-04 2.0888E-04 S3 2.7665E-02 -1.8025E-03 6.9160E-05 5.2704E-05 1.3632E-04 1.4478E-04 1.1512E-04 S4 3.1691E-02 -2.9409E-03 -3.8171E-04 -5.2859E-05 -4.8238E-05 1.9827E-06 -1.9814E-05 S5 6.7696E-02 3.3608E-03 -2.5716E-04 4.1069E-04 4.0457E-06 1.4418E-05 0.0000E+00 S6 3.5566E-01 2.9128E-02 1.3052E-02 4.1494E-03 1.5286E-03 5.8628E-04 2.3284E-04 S7 1.9278E-01 -2.9649E-02 6.5642E-03 4.2472E-04 6.8795E-04 2.2055E-04 1.3911E-04 S8 -5.4945E-02 -6.3248E-02 1.1238E-02 -2.0955E-03 9.7772E-04 -3.5345E-04 -7.6642E-05

[0142] Table 8-1

[0143] Face number A18 A20 A22 A24 A26 A28 A30 S1 1.0253E-05 -3.9314E-06 3.6838E-07 -5.8000E-06 -1.9920E-07 -1.5137E-06 2.2096E-06 S2 1.5022E-04 1.0034E-04 4.0440E-05 1.1623E-05 -4.2609E-06 -1.1117E-06 -1.1356E-06 S3 8.2148E-05 4.2837E-05 8.1699E-06 -6.6521E-06 -6.6925E-06 -1.0278E-06 2.2188E-06 S4 -1.1671E-05 -9.9831E-06 -2.3615E-07 8.7207E-07 7.0633E-07 2.6131E-06 -8.4179E-07 S5 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 7.4662E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 6.7629E-05 2.0276E-05 1.8502E-05 1.1238E-05 -9.6460E-07 -3.4858E-06 -9.1284E-06 S8 -3.8813E-05 -6.0890E-05 -1.0396E-04 -6.6057E-05 -4.5091E-05 -3.0273E-05 -5.1041E-05

[0144] Table 8-2

[0145] Figure 10A The on-axis chromatic aberration curves of the optical imaging systems of Embodiment 4-1 / Embodiment 4-2 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 10B Astigmatism curves of the optical imaging systems of Embodiment 4-1 / 4-2 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 10C The distortion curves of the optical imaging systems of Embodiment 4-1 / Embodiment 4-2 are shown, representing the distortion magnitude values ​​corresponding to different image heights. Figure 10D The magnification chromatic aberration curves of the optical imaging systems of Embodiment 4-1 / 4-2 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to... Figures 10A to 10D It can be seen that the optical imaging system given in Example 4-1 / Example 4-2 can achieve good imaging quality.

[0146] In summary, in Examples 1 to 4, the optical imaging systems respectively satisfy the conditions in Table 9.

[0147] Conditional / Example 1-1 1-2 2-1 2-2 3-1 3-2 4-1 4-2 (T12*∑AT) / (CP1*L) 0.79 0.65 0.95 0.94 0.94 0.63 0.76 0.92 f1*CT1 / (EP01*CP1) 138.23 113.10 169.13 166.49 228.07 154.90 272.60 335.06 f*(D0s-d0s) / (f1*(D1s-d1s)) 1.10 2.67 0.93 2.24 1.03 2.51 1.08 2.62 |R1+R2| / (d1s+d1m) 1.49 1.42 4.73 4.51 1.41 1.32 1.15 1.14 |f2*EP12| / (CP2*T23) 2.86 2.91 5.85 5.38 3.78 3.68 3.25 3.23 f12 / (d2m-d2s) 16.15 16.15 14.30 14.30 15.99 15.99 16.40 16.40 (R3+R4) / (CP2+CT2+EP23) -2.92 -2.92 -26.55 -25.20 -1.20 -1.14 -1.81 -1.74 |R5*CT3| / (CP2*(D2m+d2m)) 1.39 1.37 1.12 1.04 1.13 1.04 0.94 0.90 |R5+R6| / (EP12+CP2+T23) 4.48 4.52 3.25 3.27 3.18 3.18 2.96 2.94 (f3+f4) / (D3s-D2m) 0.73 0.75 0.97 0.97 0.10 0.09 0.20 0.23 f34 / (CP3+EP23+CT3+T34) 7.44 7.53 11.16 10.95 6.00 5.89 12.38 11.89 |f4*R7| / (d3s*CP3) 2.31 2.39 1.90 1.86 2.22 2.19 2.84 2.64 |R8 / (D3s+D3m)| 9.04 8.77 1.03 1.00 1.30 1.25 2.49 2.47 TAN(Semi-FOV)*f / (D0m-D3m) 1.58 1.64 1.71 1.64 1.72 1.65 1.71 1.73 f23 / (EP12+EP23) 6.28 6.20 4.38 4.26 3.20 3.04 3.07 2.88

[0148] Table 9

[0149] 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 system, characterized in that, The optical imaging system includes: The lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object side to the image side; At least one spacer element, the spacer element comprising a second spacer element located between the second lens and the third lens and in direct contact with the image-side surface of the second lens, and a third spacer element located between the third lens and the fourth lens and in direct contact with the image-side surface of the third lens; and A lens barrel for housing the lens group and the spacer element; The optical imaging system has four lenses with optical power. The first lens has positive optical power, and its object side is convex, and its image side is convex. The second lens has negative optical power, and its object side is concave, as is its image side; The third lens has positive optical power, with its object side being concave and its image side being convex. The fourth lens has negative optical power and its object side is concave. The outer diameter D3m of the image side of the third spacer element, the outer diameter D3s of the object side of the third spacer element, and the radius of curvature R8 of the image side of the fourth lens satisfy: 1.00≤|R8 / (D3s+D3m)|≤9.04; The combined focal length f34 of the third lens and the fourth lens, the maximum thickness CP3 of the third spacer element, the spacing EP23 between the second spacer element and the third spacer element, the center thickness CT3 of the third lens on the optical axis, and the air spacing T34 between the third lens and the fourth lens on the optical axis satisfy: 5.89≤f34 / (CP3+EP23+CT3+T34)≤12.

38.

2. The optical imaging system according to claim 1, wherein, The spacer element further includes a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens. The air gap T12 between the first lens and the second lens on the optical axis, the sum of the air gaps ∑AT between any two adjacent lenses from the first lens to the fourth lens on the optical axis, the maximum thickness CP1 of the first spacer element, and the maximum height L of the lens barrel satisfy: 0.63 ≤ (T12) ∑AT) / (CP1 L) < 1.

0.

3. The optical imaging system according to claim 1, wherein, The spacer element further includes a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens. The effective focal length f1 of the first lens, the center thickness CT1 of the first lens on the optical axis, the distance EP01 between the front end face of the lens barrel near the object side and the first spacer element, and the maximum thickness P1 of the first spacer element satisfy: 113.10 ≤ f1 CT1 / (EP01 CP1)≤335.

06.

4. The optical imaging system according to claim 1, wherein, The spacer element further includes a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens. The effective focal length f of the optical imaging system, the outer diameter D0s of the front face of the lens barrel closest to the object side, the inner diameter d0s of the front face of the lens barrel closest to the object side, the outer diameter D1s of the object side surface of the first spacer element, the inner diameter d1s of the object side surface of the first spacer element, and the effective focal length f1 of the first lens satisfy: 0.93 ≤ f (D0s-d0s) / (f1 (D1s-d1s))≤2.

67.

5. The optical imaging system according to claim 1, wherein, The spacer element further includes a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens. The radius of curvature R1 of the object side of the first lens, the radius of curvature R2 of the image side of the first lens, the inner diameter d1s of the object side of the first spacer element, and the inner diameter d1m of the image side of the first spacer element satisfy: 1.14≤|R1+R2| / (d1s+d1m)≤4.

73.

6. The optical imaging system according to claim 2, wherein, The effective focal length f2 of the second lens, the spacing EP12 between the first and second spacers, the maximum thickness CP2 of the second spacer, and the air gap T23 between the second and third lenses on the optical axis satisfy: 2.86 ≤ |f2| EP12| / (CP2 T23)≤5.

85.

7. The optical imaging system according to claim 1, wherein, The spacer element further includes a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens. The combined focal length f12 of the first lens and the second lens, the inner diameter d2m of the image side of the second spacer element, and the inner diameter d2s of the object side of the second spacer element satisfy: 14.30≤f12 / (d2m-d2s)≤16.

40.

8. The optical imaging system according to claim 1, wherein, The spacer element further includes a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens. The radius of curvature R3 of the object side of the second lens, the radius of curvature R4 of the image side of the second lens, the center thickness CT2 of the second lens on the optical axis, the maximum thickness CP2 of the second spacer element, and the interval EP23 between the second spacer element and the third spacer element satisfy: -26.55≤(R3+R4) / (CP2+CT2+EP23)≤-1.

14.

9. The optical imaging system according to claim 1, wherein, The spacer element further includes a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens. The radius of curvature R5 of the object-side surface of the third lens, the center thickness CT3 of the third lens on the optical axis, the maximum thickness CP2 of the second spacer element, the outer diameter D2m of the image-side surface of the second spacer element, and the inner diameter d2m of the image-side surface of the second spacer element satisfy: 0.90≤|R5 CT3| / (CP2 (D2m+d2m))≤1.

39.

10. The optical imaging system according to claim 1, wherein, The spacer element further includes a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens. The effective focal length f3 of the third lens, the effective focal length f4 of the fourth lens, the outer diameter D3s of the object side of the third spacer element, and the outer diameter D2m of the image side of the second spacer element satisfy: 0.09≤(f3+f4) / (D3s-D2m)<1.

0.

11. The optical imaging system according to claim 1, wherein, The effective focal length f4 of the fourth lens, the radius of curvature R7 of the object-side surface of the fourth lens, the inner diameter d3s of the object-side surface of the third spacer element, and the maximum thickness CP3 of the third spacer element satisfy: 1.86 ≤ |f4| R7| / (d3s CP3)≤2.

84.

12. The optical imaging system according to any one of claims 1 to 10, wherein, The semi-FOV (half of the maximum field of view) of the optical imaging system, the effective focal length f of the optical imaging system, the outer diameter D0m of the rear end face of the lens barrel closest to the image side, and the outer diameter D3m of the image side face of the third spacer element satisfy: 1.58 ≤ TAN(Semi-FOV) f / (D0m-D3m)≤1.

73.

13. The optical imaging system according to claim 6, wherein, The combined focal length f23 of the second lens and the third lens, the spacing EP12 between the first spacing element and the second spacing element, and the spacing EP23 between the second spacing element and the third spacing element satisfy: 2.88≤f23 / (EP12+EP23)≤6.

28.

14. The optical imaging system according to claim 6, wherein, The radius of curvature R5 of the object side of the third lens, the radius of curvature R6 of the image side of the third lens, the spacing EP12 between the first spacer element and the second spacer element, the maximum thickness CP2 of the second spacer element, and the air spacing T23 between the second lens and the third lens on the optical axis satisfy: 2.94≤|R5+R6| / (EP12+CP2+T23)≤4.52.

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