Optical imaging system

Abstract

An optical imaging system includes, in order from an object side to an image side along an optical axis, a first lens having a refractive power, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The optical imaging system also includes second, third, fourth, fifth, sixth, seventh, and eighth spacer elements located at image side surfaces of the second through eighth lenses, respectively. The optical imaging system satisfies: 0 < f / CT7 < 5.0 and 5.0 < f / CT8 < 12. The refractive power of any one of the first, second, fifth, sixth, seventh, and eighth lenses satisfies: 0 < f / CTj < 5.0 and 5.0 < f / CTj+1 < 12, where j is selected from 1, 2, 5, 6, 7, and 8.

Description

Technical Field

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

[0002] With the development of technology, users have placed higher demands on the photography performance of mobile phones in different scenarios, which has led the mobile phone industry to impose increasingly higher requirements on the hardware and software installed in mobile phones. In particular, in order to improve the competitiveness of their products, major smartphone manufacturers have put forward higher design requirements for the optical imaging systems installed in smartphones.

[0003] In the field of optical imaging systems, the presence of stray light and deviations in assembly stability significantly affect the imaging quality. For example, improper settings of the optical power of each lens in an optical imaging system can lead to chaotic light deflection paths, resulting in stray light. Conversely, improper design of elements such as the placement of spacers in an optical imaging system can also cause chaotic light deflection paths, leading to stray light. Furthermore, improper design of elements such as the placement of spacers can result in poor stability between lenses, leading to poor assembly stability of the optical imaging system.

[0004] Therefore, how to rationally arrange the lenses and spacers in an optical imaging system, and rationally set the optical parameters of the optical imaging system, in order to control the light path in the optical imaging system, optimize the assembly stability of the optical imaging system, and reduce the sensitivity of the optical imaging system, is one of the urgent problems to be solved in the field of optical imaging. Summary of the Invention

[0005] This application provides an optical imaging system comprising, along the optical axis from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, each having an optical power. The third lens has an optical power... Optical power of the fourth lens It can be satisfied: The optical power of the fifth lens Optical power of the sixth lens It can be satisfied: The optical power of the seventh lens Optical power of the eighth lens It can be satisfied: The optical power of any one of the following lenses: the first lens, the second lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens. It can be satisfied: as well as Where j is selected from 1, 2, 5, 6, 7, and 8. The optical imaging system also includes a second spacer element located between the second and third lenses; a third spacer element located between the third and fourth lenses; a fourth spacer element located between the fourth and fifth lenses; a fifth spacer element located between the fifth and sixth lenses; a sixth spacer element located between the sixth and seventh lenses; a seventh spacer element located between the seventh and eighth lenses; and an eighth spacer element located on the image-side surface of the eighth lens. The optical imaging system can satisfy: 5.0 < f / (CT7 + EP78 - T67) < 12, where f is the total effective focal length of the optical imaging system, CT7 is the center thickness of the seventh lens, EP78 is the spacing distance from the image-side surface of the seventh spacer element to the object-side surface of the eighth spacer element in the direction parallel to the optical axis, and T67 is the air gap between the sixth and seventh lenses on the optical axis.

[0006] In one embodiment, at least one of the object-side surfaces of the first lens to the image-side surface of the eighth lens is an aspherical mirror.

[0007] In one embodiment, the optical imaging system may satisfy: -15 < f6 / f7 / (CP6+CT7+CP7-T67) ≤ -4.0, where f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, CP6 is the maximum thickness of the sixth spacer element, CP7 is the maximum thickness of the seventh spacer element, and CT7 is the center thickness of the seventh lens.

[0008] In one embodiment, the optical imaging system may satisfy: 12≤d7s / (CT7+EP78)+d7m / (EP78+CT8)<22, where d7s is the inner diameter of the object side of the seventh spacer element, d7m is the inner diameter of the image side of the seventh spacer element, CT7 is the center thickness of the seventh lens, and CT8 is the center thickness of the eighth lens.

[0009] In one embodiment, the optical imaging system may satisfy: 14.0 < f / CT6 + (D6m - d6s) / (CT6 + T67) < 20, where D6m is the outer diameter of the image side of the sixth spacer element, d6s is the inner diameter of the object side of the sixth spacer element, and CT6 is the center thickness of the sixth lens.

[0010] In one embodiment, the optical imaging system may satisfy: -10 < (R4 + R7) / AVE(D2s, D3s) × ((T23 + T34) / EP23) < -5.0, where AVE(D2s, D3s) is the average of the outer diameters D2s of the object side of the second spacer and D3s of the object side of the third spacer, EP23 is the spacing distance between the image side of the second spacer and the object side of the third spacer in the direction parallel to the optical axis, T23 is the air gap between the second lens and the third lens on the optical axis, T34 is the air gap between the third lens and the fourth lens on the optical axis, R4 is the radius of curvature of the image side of the second lens, and R7 is the radius of curvature of the object side of the fourth lens.

[0011] In one embodiment, the optical imaging system may satisfy: 7≤AVE(f3,f4) / D3m / ((EP23+EP34) / T34)≤15, where AVE(f3,f4) is the average of the effective focal length f3 of the third lens and the effective focal length f4 of the fourth lens, D3m is the outer diameter of the image side of the third spacer element, EP23 is the spacing distance between the image side of the second spacer element and the object side of the third spacer element in the direction parallel to the optical axis, EP34 is the spacing distance between the image side of the third spacer element and the object side of the fourth spacer element in the direction parallel to the optical axis, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

[0012] In one embodiment, the optical imaging system may satisfy: 7.0 < D3s / (T34+EP34-CT4) < 12, where D3s is the outer diameter of the object side of the third spacer element, T34 is the air gap between the third lens and the fourth lens on the optical axis, EP34 is the distance between the image side of the third spacer element and the object side of the fourth spacer element in the direction parallel to the optical axis, and CT4 is the center thickness of the fourth lens.

[0013] In one embodiment, the optical imaging system may satisfy: 0 < (D(i+1)m - Dim) / EPi(i+1) < 6.5, where i is selected from 4, 5, and 6, where Dim is the outer diameter of the image side of the i-th spacer element, D(i+1)m is the outer diameter of the image side of the (i+1)-th spacer element, and EPi(i+1) is the spacing distance between the image side of the i-th spacer element and the object side of the (i+1)-th spacer element in the direction parallel to the optical axis.

[0014] In one embodiment, the optical imaging system further includes a first spacer element located between the first lens and the second lens, and the optical imaging system can satisfy: 10≤d1s / CT1×(CP1 / T12)≤15, where d1s is the inner diameter of the object side of the first spacer element, CP1 is the maximum thickness of the first spacer element, CT1 is the center thickness of the first lens, and T12 is the air gap between the first lens and the second lens on the optical axis.

[0015] In one embodiment, the optical imaging system further includes a lens barrel housing the first to eighth lenses. The optical imaging system may satisfy: 12≤D0m / (L-CT1)×(D0s / CT1)<20, where L is the maximum thickness of the lens barrel, D0m is the outer diameter of the image side of the lens barrel, D0s is the outer diameter of the object side of the lens barrel, and CT1 is the center thickness of the first lens.

[0016] In one embodiment, the optical imaging system may satisfy: 25 < (d0m - d3s) / (d0s - d3s) × (EPD / T34) < 36, where d0m is the inner diameter of the image side of the lens barrel, d0s is the inner diameter of the object side of the lens barrel, d3s is the inner diameter of the object side of the third spacer element, EPD is the entrance pupil diameter of the optical imaging system, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

[0017] In one embodiment, the optical imaging system further includes a first spacer element located between the first lens and the second lens. The optical imaging system can satisfy: 0 < CP1 / (EP01-CT1) < 2.5, where CP1 is the maximum thickness of the first spacer element, CT1 is the center thickness of the first lens, and EP01 is the distance between the object side of the lens barrel and the object side of the first spacer element in a direction parallel to the optical axis.

[0018] In one embodiment, the lens barrel is a one-piece lens barrel.

[0019] In one embodiment, the lens barrel includes a first lens barrel that houses a first lens and a second lens barrel that houses a second to an eighth lens, wherein the first lens and the second lens barrel are fixed together by adhesive material.

[0020] In an exemplary embodiment of this application, the optical power of each lens is reasonably controlled, such as satisfying... as well as It can effectively balance low-order aberrations in the imaging system, achieving a large image area while improving image quality. For example, it satisfies... That is, the third and fourth lenses have the same sign for their optical power, which is beneficial for correcting off-axis aberrations in the optical imaging system and improving image quality; satisfying The seventh and eighth lenses have opposite signs of optical power, which helps to increase the tilt angle of light rays and achieve a larger image plane. For example, by setting the first to eighth spacer elements, this application can both adjust the light path in the optical imaging system and improve the assembly stability of the optical imaging system. For example, by setting 5.0 < f / (CT7+EP78-T67) < 12, this application can effectively control the uniformity of the seventh lens, enhance its structural stability, and reduce field curvature sensitivity, thereby reducing the impact of air gap changes on the optical imaging system. 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 1A A schematic diagram of the lens group in an optical imaging system according to Embodiment 1 of this application is shown;

[0023] Figures 1B to 1D Schematic diagrams of the lens barrel and various spacer elements under three different implementations of the optical imaging system of Embodiment 1 are shown respectively.

[0024] Figures 2A to 2D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system of Example 1 are shown respectively.

[0025] Figure 3A A schematic diagram of the lens group in an optical imaging system according to Embodiment 2 of this application is shown;

[0026] Figures 3B to 3D Schematic diagrams of the lens barrel and various spacer elements under three different implementations of the optical imaging system of Embodiment 2 are shown respectively.

[0027] Figures 4A to 4D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system of Example 2 are shown respectively.

[0028] Figure 5A A schematic diagram of the lens group in an optical imaging system according to Embodiment 3 of this application is shown;

[0029] Figures 5B to 5D Schematic diagrams of the lens barrel and various spacer elements under three different implementations of the optical imaging system of Embodiment 3 are shown respectively.

[0030] Figures 6A to 6D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical imaging system of Example 3 are shown respectively; and

[0031] Figure 7 A schematic diagram showing some parameters of an optical imaging system according to an embodiment of this application is provided. 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, and the first spacer element may also be referred to as the second spacer element or the third spacer element.

[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 drawn strictly to scale. It should be understood that, for ease of illustration, the thickness, size, and shape of the spacer elements and lens barrel have also been slightly exaggerated in the accompanying drawings.

[0035] In this text, 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. It should be understood that the surface of each spacer element closest to the subject is called the object-side surface of the spacer element, and the surface of each spacer element closest to the imaging plane is called the image-side surface of the spacer element. The surface of the lens barrel closest to the subject is called the object-side surface of the lens barrel, and the surface of the lens barrel closest to the imaging plane is called the image-side surface of the lens barrel.

[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 imaging lens group (i.e., the first lens to the eighth lens), lens barrel structure, and spacer element in the various embodiments of this application can be arbitrarily combined, and it is not limited to the imaging lens group in one embodiment being only combined with the lens barrel structure, spacer element, etc. of that embodiment. The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] The features, principles and other aspects of this application are described in detail below.

[0040] An optical imaging system according to an exemplary embodiment of this application may include eight lenses with optical power, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. These eight lenses are arranged sequentially along the optical axis from the object side to the image side. Any two adjacent lenses from the first lens to the eighth lens may have a gap between them.

[0041] According to an exemplary embodiment of this application, each of the first to eighth lenses may have an optical region for optical imaging and a non-optical region extending outward from the outer periphery of the optical region. Generally speaking, the optical region refers to the area of ​​the lens used for optical imaging, while the non-optical region is the structural area of ​​the lens. During the assembly of the optical imaging system, spacer elements can be set at the non-optical regions of each lens using processes such as adhesive bonding, and each lens can be connected to the lens barrel. During the imaging process of the optical imaging system, the optical regions of each lens can transmit light from the object to form an optical path, forming the final optical image; while the non-optical regions of each assembled lens are housed in the lens barrel, which cannot transmit light, thus the non-optical regions do not directly participate in the imaging process of the optical imaging system. It should be noted that, for ease of description, this application describes each lens as divided into two parts: an optical region and a non-optical region. However, it should be understood that the optical region and the non-optical region of the lens can be formed as a whole during the manufacturing process, rather than as two separate parts.

[0042] An optical imaging system according to an exemplary embodiment of this application may include seven spacer elements located on the image-side surfaces of a second to an eighth lens, namely a second spacer element, a third spacer element, a fourth spacer element, a fifth spacer element, a sixth spacer element, a seventh spacer element, and an eighth spacer element. Specifically, the optical imaging system may include a second spacer element located between a second and a third lens, which may abut against a non-optical region on the image-side surface of the second lens; a third spacer element located between a third and a fourth lens, which may abut against a non-optical region on the image-side surface of the third lens; a fourth spacer element located between a fourth and a fifth lens, which may abut against a non-optical region on the image-side surface of the fourth lens; a fifth spacer element located between a fifth and a sixth lens, which may abut against a non-optical region on the image-side surface of the fifth lens; a sixth spacer element located between a sixth and a seventh lens, which may abut against a non-optical region on the image-side surface of the sixth lens; a seventh spacer element located between a seventh and an eighth lens, which may abut against a non-optical region on the image-side surface of the seventh lens; and an eighth spacer element located on the image-side surface of the eighth lens, which may abut against a non-optical region on the image-side surface of the eighth lens. For example, the second spacer element may contact a non-optical region on the image side of the second lens, and simultaneously contact a non-optical region on the object side of the third lens. For instance, the object side of the second spacer element may contact a non-optical region on the image side of the second lens, and the image side of the second spacer element may contact a non-optical region on the object side of the third lens; and so on, the object side of the eighth spacer element may contact a non-optical region on the image side of the eighth lens.

[0043] An optical imaging system according to an exemplary embodiment of this application may include eight spacer elements located on the image-side surfaces of the first lens to the eighth lens, namely a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, a fifth spacer element, a sixth spacer element, a seventh spacer element, and an eighth spacer element. Specifically, the optical imaging system may include a first spacer element located between a first lens and a second lens, which may abut against a non-optical region on the image-side side of the first lens; a second spacer element located between a second lens and a third lens, which may abut against a non-optical region on the image-side side of the second lens; a third spacer element located between a third lens and a fourth lens, which may abut against a non-optical region on the image-side side of the third lens; a fourth spacer element located between a fourth lens and a fifth lens, which may abut against a non-optical region on the image-side side of the fourth lens; a fifth spacer element located between a fifth lens and a sixth lens, which may abut against a non-optical region on the image-side side of the fifth lens; a sixth spacer element located between a sixth lens and a seventh lens, which may abut against a non-optical region on the image-side side of the sixth lens; a seventh spacer element located between a seventh lens and an eighth lens, which may abut against a non-optical region on the image-side side of the seventh lens; and an eighth spacer element located on the image-side side of the eighth lens, which may abut against a non-optical region on the image-side side of the eighth lens. Exemplarily, the first spacer element may contact the non-optical region on the image-side side of the first lens and simultaneously contact the non-optical region on the object-side side of the second lens. For example, the object-side surface of the first spacer element may contact the non-optical region of the image-side surface of the first lens, and the image-side surface of the first spacer element may contact the non-optical region of the object-side surface of the second lens; and so on, the object-side surface of the eighth spacer element may contact the non-optical region of the image-side surface of the eighth lens.

[0044] An optical imaging system according to an exemplary embodiment of this application may include a lens barrel housing a first lens to an eighth lens. Exemplarily, such as... Figure 1B and Figure 1C As shown, the lens barrel 100 can be a segmented lens barrel, such as a two-section lens barrel. Specifically, the lens barrel 100 may include a first lens barrel 110 and a second lens barrel 120. The first lens barrel 110 can accommodate a first lens, and the second lens barrel 120 can accommodate a second to an eighth lens. In this case, the optical imaging system may include seven spacer elements P2 to P8 respectively located on the image-side surfaces of the second to eighth lenses. Exemplarily, the first lens and the second lens barrel 120 can be fixed by adhesive material, for example, by dispensing adhesive to fix the first lens to the second lens barrel 120. Exemplarily, the first lens can be a glass lens. Fixing the first lens to the second lens barrel by dispensing adhesive can reduce the impact of radial pressure on the glass lens from the second lens barrel on the field area, improving performance yield. In addition, since glass lenses are expensive, this assembly method allows the first lens to be reused, which is beneficial to improving utilization and achieving the effect of reducing costs.

[0045] In another exemplary embodiment, such as Figure 1D As shown, the lens barrel 100' can be a one-piece lens barrel that can accommodate the first lens to the eighth lens. In this case, the optical imaging system may include eight spacer elements P1 to P8 respectively located on the image-side surface of the first lens to the eighth lens.

[0046] According to an exemplary embodiment of this application, the spacer element may include at least one spacer plate. By reasonably setting the number, thickness, inner diameter, and outer diameter of the spacers, it is beneficial to improve the assembly of the optical imaging system, to block stray light, and to improve the imaging quality of the optical imaging system. Exemplarily, the spacer element may also include at least one spacer ring. By controlling the thickness and structure of the spacer ring, it is beneficial to improve the assembly stability of the optical imaging system. Exemplarily, the eighth spacer element may include at least one pressure ring, which is beneficial to improve the stability of the assembled optical imaging system and make the optical imaging system reliable.

[0047] According to an exemplary embodiment of this application, the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens can all have positive or negative optical power. For example, the optical power of the third lens... Optical power of the fourth lens It can be satisfied: The optical power of the fifth lens Optical power of the sixth lens It can be satisfied: The optical power of the seventh lens Optical power of the eighth lens It can be satisfied: The optical power of any one of the following lenses: the first lens, the second lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens. It can be satisfied: as well as Where j is selected from 1, 2, 5, 6, 7, 8.

[0048] In an exemplary embodiment, the optical imaging system according to this application satisfies: 5.0 < f / (CT7+EP78-T67) < 12, where f is the total effective focal length of the optical imaging system, CT7 is the center thickness of the seventh lens, EP78 is the distance between the image side of the seventh spacer element and the object side of the eighth spacer element in the direction parallel to the optical axis, and T67 is the air gap between the sixth and seventh lenses on the optical axis. More specifically, f, CT7, EP78, and T67 can further satisfy: 5.8 < f / (CT7+EP78-T67) < 11. Satisfying 5.0 < f / (CT7+EP78-T67) < 12 can effectively control the uniformity of the seventh lens, enhance the structural stability of the seventh lens, reduce field curvature sensitivity, and thus help reduce the impact of air gap changes on the imaging system.

[0049] In an exemplary embodiment, the optical imaging system according to this application satisfies: -15 < f6 / f7 / (CP6+CT7+CP7-T67) ≤ -4.0, where f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, and CP6 is the maximum thickness of the sixth spacer element. Figure 7 CP7 is the maximum thickness of the seventh spacer element, and CT7 is the center thickness of the seventh lens. Satisfying -15 < f6 / f7 / (CP6+CT7+CP7-T67) ≤ -4.0 is beneficial for reducing the air gap between the sixth and seventh lenses on the optical axis, as well as the edge thickness of the sixth and seventh spacer elements. This reduces the structural sensitivity of the sixth and seventh spacer elements, thereby reducing the impact of the air gap on the imaging system's sensitivity.

[0050] In an exemplary embodiment, the optical imaging system according to this application satisfies: 12≤d7s / (CT7+EP78)+d7m / (EP78+CT8)<22, where d7s is the inner diameter of the object-side surface of the seventh spacer element, and d7m is the inner diameter of the image-side surface of the seventh spacer element. Figure 7 CT7 is the center thickness of the seventh lens, and CT8 is the center thickness of the eighth lens. More specifically, d7s, CT7, EP78, d7m, and CT8 can further satisfy: 12 ≤ d7s / (CT7+EP78) + d7m / (EP78+CT8) < 21.5. Satisfying 12 ≤ d7s / (CT7+EP78) + d7m / (EP78+CT8) < 22 is beneficial for reducing the stray light intensity of the seventh spacer element, reducing the angle at which stray light is generated, and improving the imaging quality of the imaging system.

[0051] In an exemplary embodiment, the optical imaging system according to this application satisfies: 14.0 < f / CT6 + (D6m - d6s) / (CT6 + T67) < 20, where D6m is the outer diameter of the image-side surface of the sixth spacer element, d6s is the inner diameter of the object-side surface of the sixth spacer element, and CT6 is the center thickness of the sixth lens. More specifically, f, CT6, D6m, d6s, CT6, and T67 further satisfy: 14.0 < f / CT6 + (D6m - d6s) / (CT6 + T67) < 18.5. Satisfying 14.0 < f / CT6 + (D6m - d6s) / (CT6 + T67) < 20 is beneficial for effectively controlling the thickness ratio of the sixth lens, enhancing the structural stability of the sixth lens, and reducing field curvature sensitivity.

[0052] In an exemplary embodiment, the optical imaging system according to this application satisfies: -10 < (R4 + R7) / AVE(D2s, D3s) × ((T23 + T34) / EP23) < -5.0, where AVE(D2s, D3s) is the average of the outer diameters D2s of the object side of the second spacer and D3s of the object side of the third spacer, and EP23 is the spacing distance between the image side of the second spacer and the object side of the third spacer in the direction parallel to the optical axis. Figure 7 T23 is the air gap between the second and third lenses on the optical axis, T34 is the air gap between the third and fourth lenses on the optical axis, R4 is the radius of curvature of the image side of the second lens, and R7 is the radius of curvature of the object side of the fourth lens. Satisfying -10 < (R4 + R7) / AVE(D2s, D3s) × ((T23 + T34) / EP23) < -5.0 is beneficial for controlling the second air gap element within a reasonable range, avoiding the generation of water ripple stray light, and also helps control the sensitivity of the air gap between the second and third lenses, thereby reducing the impact of air gap changes on the imaging system and enabling the imaging system to achieve better performance and reliability.

[0053] In an exemplary embodiment, the optical imaging system according to this application satisfies: 7≤AVE(f3,f4) / D3m / ((EP23+EP34) / T34)≤15, where AVE(f3,f4) is the average of the effective focal length f3 of the third lens and the effective focal length f4 of the fourth lens, D3m is the outer diameter of the image-side surface of the third spacer element, EP23 is the distance between the image-side surface of the second spacer element and the object-side surface of the third spacer element in the direction parallel to the optical axis, EP34 is the distance between the image-side surface of the third spacer element and the object-side surface of the fourth spacer element in the direction parallel to the optical axis, and T34 is the air gap between the third lens and the fourth lens on the optical axis. Satisfying 7≤AVE(f3,f4) / D3m / ((EP23+EP34) / T34)≤15 is beneficial for effectively reducing the field sensitivity of the fourth spacer element and ensuring the thickness ratio of the third lens and the fourth lens. Once the third and fourth lenses are formed and stabilized, it will be easier to make the forming process of the seventh and eighth lenses gentler, reducing the deformation of the lens outer diameter caused by internal stress.

[0054] In an exemplary embodiment, the optical imaging system according to this application satisfies: 7.0 < D3s / (T34+EP34-CT4) < 12, where D3s is the outer diameter of the object-side surface of the third spacer element, T34 is the air gap between the third and fourth lenses on the optical axis, EP34 is the distance between the image-side surface of the third spacer element and the object-side surface of the fourth spacer element in a direction parallel to the optical axis, and CT4 is the center thickness of the fourth lens. Satisfying 7.0 < D3s / (T34+EP34-CT4) < 12 is beneficial for keeping the ratio of the outer diameter to the center thickness of the third lens within a reasonable range, ensuring the feasibility of the molding process, and also for keeping the air gap between the third and fourth lenses small, which is beneficial for improving assembly stability and reducing the sensitivity of the air gap to the imaging system.

[0055] In an exemplary embodiment, the optical imaging system according to this application satisfies: 0 < (D(i+1)m - Dim) / EPi(i+1) < 6.5, where i is selected from 4, 5, and 6, Dim is the outer diameter of the image-side surface of the i-th spacer element, D(i+1)m is the outer diameter of the image-side surface of the (i+1)-th spacer element, and EPi(i+1) is the distance between the image-side surface of the i-th spacer element and the object-side surface of the (i+1)-th spacer element in the direction parallel to the optical axis. Satisfying 0 < (D(i+1)m - Dim) / EPi(i+1) < 6.5 is beneficial for reducing the radial step difference of the air gap between the fourth and sixth lenses, ensuring the assembly stability of the lenses, reducing structural sensitivity, and also for reducing the risk of stray light generated by the fifth spacer element, thereby improving the imaging quality of the imaging system.

[0056] In an exemplary embodiment, the optical imaging system according to this application satisfies: 10 ≤ d1s / CT1 × (CP1 / T12) ≤ 15, where d1s is the inner diameter of the object side of the first spacer element ( Figure 7 CP1 is the maximum thickness of the first spacer element, CT1 is the center thickness of the first lens, and T12 is the air gap between the first and second lenses on the optical axis. Satisfying 10 ≤ d1s / CT1 × (CP1 / T12) ≤ 15 is beneficial for effectively improving edge stray light of the first lens, reducing ghosting in the optical imaging system, and improving the imaging capability of the optical imaging system. Simultaneously, by reasonably setting the inner diameter of the first spacer element, the flatness of each lens can be improved, and assembly tilt can be reduced.

[0057] In an exemplary embodiment, the optical imaging system according to this application satisfies: 12 ≤ D0m / (L-CT1)×(D0s / CT1) < 20, where L is the maximum thickness of the lens barrel, and D0m is the outer diameter of the image-side surface of the lens barrel. Figure 7 D0s is the outer diameter of the object side of the microscope tube. Figure 7 ), and CT1 is the center thickness of the first lens. Satisfying 12≤D0m / (L-CT1)×(D0s / CT1)<20 helps to avoid the impact of large differences in lens barrel thickness on the formation of the optical imaging system. By controlling the ratio of the outer diameter of the object side and the image side of the lens barrel, it is beneficial to control the uniformity of the lens barrel wall thickness, improve the overall structural strength, and obtain better assembly performance and lens barrel appearance.

[0058] In an exemplary embodiment, the optical imaging system according to this application satisfies: 25 < (d0m - d3s) / (d0s - d3s) × (EPD / T34) < 36, where d0m is the inner diameter of the image-side surface of the lens barrel ( Figure 7 ), d0s is the inner diameter of the object side of the microscope tube ( Figure 7 d3s is the inner diameter of the object side of the third spacer element, EPD is the entrance pupil diameter of the optical imaging system, and T34 is the air gap between the third and fourth lenses on the optical axis. Satisfying 25 < (d0m - d3s) / (d0s - d3s) × (EPD / T34) < 36 helps reduce stray feather light. Furthermore, controlling the air gap between the third and fourth lenses improves field curvature stability, enhances overall structural strength, and achieves better reliability.

[0059] In an exemplary embodiment, the optical imaging system according to this application satisfies: 0 < CP1 / (EP01-CT1) < 2.5, where CP1 is the maximum thickness of the first spacer element, CT1 is the center thickness of the first lens, and EP01 is the distance between the object side of the lens barrel and the object side of the first spacer element in the direction parallel to the optical axis. Satisfying 0 < CP1 / (EP01-CT1) < 2.5 is beneficial for effectively improving the smoothness of the first lens, reducing ghosting in the optical imaging system, and improving the imaging capability of the optical imaging system. At the same time, by reasonably controlling the reasonable inner diameter of the first spacer element, the flatness of each lens can be improved, and assembly tilt can be reduced.

[0060] In an exemplary embodiment, the optical imaging system according to this application further includes an aperture stop disposed between the object side and the first lens. Optionally, the optical imaging system may also include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface. This application proposes an optical imaging system with characteristics such as good assembly stability, low stray light, and high imaging quality. The optical imaging system according to the above embodiments of this application can employ multiple lenses, such as the eight lenses mentioned above. By rationally allocating the optical power, surface shape, material, center thickness of each lens, and on-axis spacing between each lens, incident light can be effectively converged, the overall optical length of the imaging lens can be reduced, and the manufacturability of the imaging lens can be improved, making the optical imaging system more conducive to manufacturing.

[0061] In the embodiments of this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one mirror surface from the object-side surface of the first lens to the image-side surface of the eighth lens is an aspherical mirror surface. The characteristic of an aspherical lens is that its curvature changes continuously from the center to the periphery of the lens. Unlike a spherical lens, which has a constant curvature from the center to the periphery, an aspherical lens has better radius of curvature characteristics, and has the advantages of improving distortion aberrations and astigmatism aberrations. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. Optionally, at least one of the object-side and image-side surfaces of each of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses is an aspherical mirror surface. Optionally, both the object-side and image-side surfaces of each of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are aspherical mirror surfaces.

[0062] 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 eight lenses are described as an example in the embodiments, the optical imaging system is not limited to including eight lenses. If desired, the optical imaging system may also include other numbers of lenses. At least one spacer may be included between any two adjacent lenses.

[0063] Specific embodiments of the optical imaging system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0064] Example 1

[0065] The following is for reference Figures 1A to 2D An optical imaging system according to Embodiment 1 of this application is described. Figure 1A A schematic diagram of the lens group in an optical imaging system according to Embodiment 1 of this application is shown; and Figures 1B to 1D Schematic diagrams of the lens barrel and various spacer elements in three different implementations of the optical imaging system of Embodiment 1 are shown respectively.

[0066] like Figure 1A As shown, the optical imaging system includes, from the object side to the image side, the following components in sequence: aperture STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, seventh lens E7, eighth lens E8, filter E9, and imaging surface S19.

[0067] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The eighth lens E8 has negative optical power, with its object-side surface S15 being concave and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes sequentially through each surface S1 to S18 and is finally imaged onto the imaging surface S19.

[0068] Table 1 shows the basic parameters of the optical imaging system of Example 1, where the units for radius of curvature, thickness / distance, and focal length are millimeters (mm).

[0069]

[0070]

[0071] Table 1

[0072] like Figure 1B and Figure 1C As shown, the optical imaging system may include a segmented lens barrel 100 housing a first lens to an eighth lens. The segmented lens barrel 100 may include a first lens barrel 110 and a second lens barrel 120. The first lens barrel 110 houses the first lens, and the second lens barrel 120 houses the second to eighth lenses. The optical imaging system may include seven spacer elements located on the image-side surfaces of the second to eighth lenses, namely, second spacer element P2, third spacer element P3, fourth spacer element P4, fifth spacer element P5, sixth spacer element P6', seventh spacer element P7, and eighth spacer element P8.

[0073] For example, such as Figure 1B As shown, the second spacer element P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. By setting appropriate spacers, stray light can be blocked, improving the imaging quality of the optical imaging system. The sixth spacer element P6' may include a first spacer P6, a second spacer P6c, and a spacer ring P6b located between the first spacer P6 and the second spacer P6c, wherein the first spacer P6 is closer to the object side of the optical imaging system, and the second spacer P6c is closer to the image side of the optical imaging system. The seventh spacer element P7 may include a spacer ring. By controlling the thickness and structure of spacers P6b and P7, the assembly stability of the optical imaging system can be improved. The eighth spacer element P8 may include a retaining ring. Providing a retaining ring P8 at the image side of the eighth lens improves the stability of the assembled optical imaging system, making the optical imaging system reliable.

[0074] For example, such as Figure 1CAs shown, the second spacer element P2, the third spacer element P3, the fourth spacer element P4, the fifth spacer element P5, and the seventh spacer element P7 can be spacers. By setting appropriate spacers, stray light can be blocked, improving the imaging quality of the optical imaging system. The sixth spacer element P6' may include a first spacer P6, a second spacer P6c, and a spacer ring P6b located between the first spacer P6 and the second spacer P6c. The first spacer P6 is closer to the object side of the optical imaging system, and the second spacer P6c is closer to the image side. By controlling the thickness and structure of the spacer ring P6b, the assembly stability of the optical imaging system can be improved. The eighth spacer element P8 can be a retaining ring. Setting the retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system reliable.

[0075] like Figure 1D As shown, the optical imaging system may include an integral lens barrel 100' housing a first lens to an eighth lens. The optical imaging system may include eight spacer elements located on the image-side surfaces of the first to eighth lenses, namely, a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, a fifth spacer element P5, a sixth spacer element P6', a seventh spacer element P7, and an eighth spacer element P8. The first spacer element P1 may include a spacer ring. Controlling the thickness and structure of the spacer ring P1 can improve the assembly stability of the optical imaging system. The second spacer element P2, the third spacer element P3, the fourth spacer element P4, the fifth spacer element P5, and the seventh spacer element P7 may include spacers. Properly positioned spacers can help block stray light and improve the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer ring P6 and a spacer ring P6b, wherein the spacer ring P6 is closer to the object side of the optical imaging system, and the spacer ring P6b is closer to the image side of the optical imaging system. Controlling the thickness and structure of the spacer ring P6b can improve the assembly stability of the optical imaging system. The eighth spacer element P8 may include a retaining ring. Providing the retaining ring P8 on the image-side surface of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system more reliable.

[0076] Table 2 shows the basic parameters of the lens barrel and each spacer element under three implementations of the optical imaging system of Example 1. In Table 2, the unit of each parameter is millimeters (mm).

[0077]

[0078]

[0079] It should be understood that this example only exemplifies the structure and parameters of the lens barrel and each spacer element under three implementation methods, and does not explicitly limit the specific structure and actual parameters of the lens barrel and each spacer element. In actual production, the specific structure and actual parameters of the lens barrel and each spacer element can be set in any suitable manner.

[0080] In this example, the total effective focal length f of the optical imaging system is 9.44 mm, and the aperture value Fno of the optical imaging system is 1.86.

[0081] In Embodiment 1, the object-side surface and image-side surface of any one of the first lens E1 to the eighth lens E8 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:

[0082]

[0083] 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 3-1 and 3-2 below give the higher-order coefficients A4, A6, A8, A16, A26, A36, A47, A18, A19 ... 10 A 12 A 14 A 16 A 18 A 20 A 22 A 24 A 26 A 28 and A 30 .

[0084]

[0085]

[0086] Table 3-1

[0087] Face number A18 A20 A22 A24 A26 A28 A30 S1 3.2116E-10 -5.0235E-11 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 1.5577E-08 -4.2757E-10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -8.5593E-07 6.7578E-08 -2.2409E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 6.9450E-07 -4.1361E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 1.9598E-06 -9.7709E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 1.4152E-06 -1.8306E-07 9.5762E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 -1.1303E-06 3.6755E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 1.4500E-05 -3.1371E-06 3.8457E-07 -2.5945E-08 7.5227E-10 0.0000E+00 0.0000E+00 S9 -1.0854E-06 -3.0638E-08 1.1454E-08 -8.3848E-10 2.1918E-11 0.0000E+00 0.0000E+00 S10 -1.9630E-06 1.4818E-07 -7.3735E-09 2.1555E-10 -2.7898E-12 0.0000E+00 0.0000E+00 S11 -1.0426E-05 1.2479E-06 -1.0745E-07 6.4673E-09 -2.5787E-10 6.1123E-12 -6.5156E-14 S12 -2.6415E-08 7.9249E-10 -6.6022E-13 -5.4941E-13 9.5626E-15 0.0000E+00 0.0000E+00 S13 2.1053E-08 -9.8698E-10 3.2447E-11 -7.3183E-13 1.0786E-14 -9.3574E-17 3.6239E-19 S14 -7.2829E-09 2.5919E-10 -6.7784E-12 1.2638E-13 -1.5869E-15 1.2004E-17 -4.1253E-20 S15 -4.3828E-09 1.2876E-10 -2.7167E-12 4.0149E-14 -3.9462E-16 2.3172E-18 -6.1497E-21 S16 -1.1089E-09 2.5392E-11 -4.0005E-13 4.1255E-15 -2.5057E-17 6.7924E-20 0.0000E+00

[0088] Table 3-2

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

[0090] Example 2

[0091] The following is for reference Figures 3A to 4D An optical imaging system according to Embodiment 2 of this application is described. In this embodiment and the following embodiments, for the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted. Figure 3A A schematic diagram of the lens group in an optical imaging system according to Embodiment 2 of this application is shown; and Figures 3B to 3D Schematic diagrams of the lens barrel and various spacer elements in three different implementations of the optical imaging system of Embodiment 2 are shown respectively.

[0092] like Figure 3A As shown, the optical imaging system includes, from the object side to the image side, the following components in sequence: aperture STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, seventh lens E7, eighth lens E8, filter E9, and imaging surface S19.

[0093] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The eighth lens E8 has negative optical power, with its object-side surface S15 being concave and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes sequentially through each surface S1 to S18 and is finally imaged onto the imaging surface S19.

[0094] like Figure 3B and Figure 3CAs shown, the optical imaging system may include a segmented lens barrel 100 housing a first lens to an eighth lens. The segmented lens barrel 100 may include a first lens barrel 110 and a second lens barrel 120. The first lens barrel 110 houses the first lens, and the second lens barrel 120 houses the second to eighth lenses. The optical imaging system may include seven spacer elements located on the image-side surfaces of the second to eighth lenses, namely, second spacer element P2, third spacer element P3, fourth spacer element P4, fifth spacer element P5, sixth spacer element P6', seventh spacer element P7', and eighth spacer element P8.

[0095] For example, such as Figure 3B As shown, the second spacer element P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. By setting appropriate spacers, stray light can be blocked, improving the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer P6 and a spacer ring P6b, wherein the spacer P6 is close to the object side of the optical imaging system, and the spacer ring P6b is close to the image side of the optical imaging system. The seventh spacer element P7' may include a spacer P7 and a spacer ring P7b, wherein the spacer P7 is close to the object side of the optical imaging system, and the spacer ring P7b is close to the image side of the optical imaging system. By controlling the thickness and structure of the spacers P6b and P7b, the assembly stability of the optical imaging system can be improved. The eighth spacer element P8 may include a retaining ring. Setting the retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system reliable.

[0096] For example, such as Figure 3C As shown, the second spacer element P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. By setting appropriate spacers, stray light can be blocked, improving the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer P6 and a spacer ring P6b, wherein the spacer P6 is close to the object side of the optical imaging system, and the spacer ring P6b is close to the image side of the optical imaging system. The seventh spacer element P7' may include a spacer ring P7 and a spacer P7b, wherein the spacer ring P7 is close to the object side of the optical imaging system, and the spacer ring P7b is close to the image side of the optical imaging system. By controlling the thickness and structure of the spacers P6b and P7, the assembly stability of the optical imaging system can be improved. The eighth spacer element P8 may include a retaining ring. Setting the retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system reliable.

[0097] like Figure 3DAs shown, the optical imaging system may include an integral lens barrel 100' housing a first lens to an eighth lens. The optical imaging system may include eight spacer elements located on the image-side surfaces of the first to eighth lenses, namely, a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, a fifth spacer element P5, a sixth spacer element P6', a seventh spacer element P7', and an eighth spacer element P8. The first spacer element P1 may include a spacer ring. Controlling the thickness and structure of the spacer ring P1 helps improve the assembly stability of the optical imaging system. The second spacer elements P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. Properly positioned spacers help block stray light and improve the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer ring P6 and a spacer plate P6b, wherein the spacer ring P6 is closer to the object side of the optical imaging system, and the spacer plate P6b is closer to the image side of the optical imaging system. The seventh spacer element P7' may include a first spacer P7, a second spacer P7c, and a spacer ring P7b located between the first spacer P7 and the second spacer P7c. The first spacer P7 is closer to the object side of the optical imaging system, and the second spacer P7c is closer to the image side of the optical imaging system. Controlling the thickness and structure of spacers P6 and P7b helps improve the assembly stability of the optical imaging system. The eighth spacer element P8 may include a retaining ring. Providing a retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system more reliable.

[0098] In this example, the total effective focal length f of the optical imaging system is 8.55 mm, and the aperture value Fno of the optical imaging system is 1.86.

[0099] Table 4 shows the basic parameters of the optical imaging system of Embodiment 2, wherein the units of radius of curvature, thickness / distance, and focal length are all millimeters (mm). Table 5 shows the basic parameters of the lens barrel and each spacer element under three implementations of the optical imaging system of Embodiment 2, wherein the units of each parameter in Table 5 are all millimeters (mm). Tables 6-1 and 6-2 show the higher-order coefficients that can be used for each aspherical mirror in Embodiment 2, wherein each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0100]

[0101] Table 4

[0102] Structural parameters Implementation Method 1 Implementation Method 2 Implementation Method 3 d1s / / 4.44 D2s 6.80 5.69 5.69 d3s 3.91 3.91 3.91 D3s 7.00 5.66 5.66 D3m 7.00 5.66 5.66 D4m 7.30 7.30 7.30 D5m 8.10 8.50 8.50 d6s 7.04 7.04 7.36 D6m 10.50 9.66 10.40 d7s 10.38 10.46 10.31 d7m 10.38 11.71 10.31 D7m 12.60 12.50 12.21 d0s 6.81 6.81 6.49 d0m 15.08 15.08 14.88 D0s 9.53 9.53 7.32 D0m 15.36 15.36 15.16 EP01 / / 1.38 CP1 / / 0.32 EP23 0.37 0.37 0.37 EP34 0.56 0.56 0.56 EP45 0.57 0.57 0.57 EP56 0.42 0.42 0.43 CP6 0.02 0.02 0.67 EP67 1.05 1.07 0.38 CP7 0.02 0.65 0.02 EP78 1.16 0.51 1.16 L 8.65 8.65 8.65

[0103] Table 5

[0104]

[0105]

[0106] Table 6-1

[0107] Face number A18 A20 A22 A24 A26 A28 A30 S1 1.7760E-07 -1.0012E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -7.7390E-07 3.3268E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -2.0925E-05 2.0445E-06 -8.4773E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 -2.5283E-06 2.7731E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 1.2740E-05 -7.5728E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 7.4196E-05 -1.0069E-05 5.8795E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 4.8973E-06 -5.0774E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 8.7542E-04 -1.9448E-04 2.7338E-05 -2.2137E-06 7.8831E-08 0.0000E+00 0.0000E+00 S9 -5.8169E-06 -1.4788E-06 3.3498E-07 -2.8473E-08 9.2746E-10 0.0000E+00 0.0000E+00 S10 -2.4530E-05 2.5451E-06 -1.7274E-07 6.8580E-09 -1.2028E-10 0.0000E+00 0.0000E+00 S11 -1.6046E-04 2.6604E-05 -3.1714E-06 2.6411E-07 -1.4558E-08 4.7662E-10 -7.0105E-12 S12 -1.9473E-06 1.4631E-07 -6.9438E-09 1.8911E-10 -2.2576E-12 0.0000E+00 0.0000E+00 S13 1.3372E-07 -7.6340E-09 3.0797E-10 -8.5704E-12 1.5638E-13 -1.6825E-15 8.0832E-18 S14 -5.1670E-08 2.3526E-09 -7.8798E-11 1.8858E-12 -3.0530E-14 2.9971E-16 -1.3479E-18 S15 6.3166E-09 -2.2876E-10 6.0239E-12 -1.1240E-13 1.4082E-15 -1.0619E-17 3.6384E-20 S16 3.1718E-09 -9.6808E-11 2.0433E-12 -2.8385E-14 2.3358E-16 -8.6259E-19 0.0000E+00

[0108] Table 6-2

[0109] Figure 4A The on-axis chromatic aberration curve of the optical imaging system of Embodiment 2 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 4B The astigmatism curves of the optical imaging system of Embodiment 2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 4C The distortion curves of the optical imaging system of Example 2 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 4D The magnification chromatic aberration curve of the optical imaging system of Embodiment 2 is shown, which represents the deviation of different image heights on the imaging plane after light passes through the lens. According to Figures 4A to 4D It can be seen that the optical imaging system given in Example 2 can achieve good imaging quality.

[0110] Example 3

[0111] The following is for reference Figures 5A to 6D An optical imaging system according to Embodiment 3 of this application is described. Figure 5A A schematic diagram of the lens group in an optical imaging system according to Embodiment 3 of this application is shown; and Figures 5B to 5D Schematic diagrams of the lens barrel and various spacer elements in three different implementations of the optical imaging system of Embodiment 3 are shown respectively.

[0112] like Figure 5A As shown, the optical imaging system includes, from the object side to the image side, the following components in sequence: aperture STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6, seventh lens E7, eighth lens E8, filter E9, and imaging surface S19.

[0113] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The eighth lens E8 has negative optical power, with its object-side surface S15 being concave and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes sequentially through each surface S1 to S18 and is finally imaged onto the imaging surface S19.

[0114] like Figure 5B and Figure 5C As shown, the optical imaging system may include a segmented lens barrel 100 housing a first lens to an eighth lens. The segmented lens barrel 100 may include a first lens barrel 110 and a second lens barrel 120. The first lens barrel 110 houses the first lens, and the second lens barrel 120 houses the second to eighth lenses. The optical imaging system may include seven spacer elements located on the image-side surfaces of the second to eighth lenses, namely, second spacer element P2, third spacer element P3, fourth spacer element P4, fifth spacer element P5, sixth spacer element P6', seventh spacer element P7', and eighth spacer element P8.

[0115] For example, such as Figure 5B As shown, the second spacer element P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. By setting appropriate spacers, stray light can be blocked, improving the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer ring P6 and a spacer P6b, wherein the spacer ring P6 is close to the object side of the optical imaging system, and the spacer P6b is close to the image side of the optical imaging system. The seventh spacer element P7' may include a spacer P7 and a spacer ring P7b, wherein the spacer P7 is close to the object side of the optical imaging system, and the spacer ring P7b is close to the image side of the optical imaging system. By controlling the thickness and structure of the spacer rings P6 and P7b, the assembly stability of the optical imaging system can be improved. The eighth spacer element P8 may include a retaining ring. Setting the retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system reliable.

[0116] For example, such as Figure 5CAs shown, the second spacer element P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. By setting appropriate spacers, stray light can be blocked, improving the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer P6 and a spacer ring P6b, wherein the spacer P6 is close to the object side of the optical imaging system, and the spacer ring P6b is close to the image side of the optical imaging system. The seventh spacer element P7' may include a spacer P7 and a spacer ring P7b, wherein the spacer P7 is close to the object side of the optical imaging system, and the spacer ring P7b is close to the image side of the optical imaging system. By controlling the thickness and structure of the spacers P6b and P7b, the assembly stability of the optical imaging system can be improved. The eighth spacer element P8 may include a retaining ring. Setting the retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system reliable.

[0117] like Figure 5D As shown, the optical imaging system may include an integral lens barrel 100' housing a first lens to an eighth lens. The optical imaging system may include eight spacer elements located on the image-side surfaces of the first to eighth lenses, namely, a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, a fifth spacer element P5, a sixth spacer element P6', a seventh spacer element P7', and an eighth spacer element P8. The first spacer element P1 may include a spacer ring. Controlling the thickness and structure of the spacer ring P1 helps improve the assembly stability of the optical imaging system. The second spacer elements P2, the third spacer element P3, the fourth spacer element P4, and the fifth spacer element P5 may include spacers. Properly positioned spacers help block stray light and improve the imaging quality of the optical imaging system. The sixth spacer element P6' may include a spacer ring P6 and a spacer plate P6b, wherein the spacer ring P6 is closer to the object side of the optical imaging system, and the spacer plate P6b is closer to the image side of the optical imaging system. The seventh spacer element P7' may include a first spacer P7, a second spacer P7c, and a spacer ring P7b located between the first spacer P7 and the second spacer P7c. The first spacer P7 is closer to the object side of the optical imaging system, and the second spacer P7c is closer to the image side of the optical imaging system. Controlling the thickness and structure of spacers P6 and P7b helps improve the assembly stability of the optical imaging system. The eighth spacer element P8 may include a retaining ring. Providing a retaining ring P8 at the image side of the eighth lens helps improve the stability of the assembled optical imaging system, making the optical imaging system more reliable.

[0118] In this example, the total effective focal length f of the optical imaging system is 8.87 mm, and the aperture value Fno of the optical imaging system is 1.86.

[0119] Table 7 shows the basic parameters of the optical imaging system of Embodiment 3, wherein the units of radius of curvature, thickness / distance, and focal length are all millimeters (mm). Table 8 shows the basic parameters of the lens barrel and each spacer element in the three embodiments of the optical imaging system of Embodiment 3, wherein the units of each parameter in Table 8 are all millimeters (mm). Tables 9-1 and 9-2 show the higher-order coefficients that can be used for each aspherical mirror in Embodiment 3, wherein each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0120]

[0121]

[0122] Table 7

[0123] Structural parameters Implementation Method 1 Implementation Method 2 Implementation Method 3 d1s / / 5.17 D2s 6.80 6.80 6.80 d3s 4.08 4.08 4.08 D3s 5.57 7.00 5.57 D3m 5.57 7.00 5.57 D4m 7.30 7.30 7.30 D5m 9.00 8.40 9.00 d6s 7.36 7.20 7.36 D6m 10.17 10.50 10.43 d7s 10.71 10.71 10.71 d7m 10.71 10.71 10.71 D7m 12.80 12.80 12.80 d0s 6.81 6.81 6.81 d0m 15.08 15.08 15.08 D0s 7.91 9.53 7.91 D0m 15.36 15.36 15.36 EP01 / / 1.34 CP1 / / 0.38 EP23 0.39 0.39 0.39 EP34 0.62 0.62 0.62 EP45 0.66 0.66 0.66 EP56 0.46 0.44 0.46 CP6 0.75 0.02 0.75 EP67 0.44 1.19 0.44 CP7 0.02 0.02 0.02 EP78 1.19 1.19 1.19 L 8.65 8.65 8.65

[0124] Table 8

[0125] Face number A4 A6 A8 A10 A12 A14 A16 S1 5.2693E-05 7.7979E-05 -8.4292E-05 3.9958E-05 -1.3228E-05 2.6751E-06 -3.9186E-07 S2 -4.5666E-03 1.1663E-03 -5.2271E-05 -1.3580E-04 7.4976E-05 -2.2144E-05 3.8427E-06 S3 -6.0495E-03 1.0772E-03 6.2269E-04 -7.1511E-04 4.5205E-04 -1.8316E-04 4.7594E-05 S4 -2.5064E-03 2.6417E-04 5.4184E-04 -3.3411E-04 1.4311E-04 -3.2414E-05 2.1953E-06 S5 -3.5943E-03 4.7866E-05 -5.9429E-04 7.2370E-04 -4.2675E-04 1.6462E-04 -3.8442E-05 S6 -3.5785E-03 -2.1222E-04 -7.0589E-04 1.0956E-03 -8.9770E-04 4.8553E-04 -1.6834E-04 S7 -5.9879E-03 -3.0039E-03 9.2640E-04 -6.8429E-04 2.2546E-04 -2.5748E-05 -5.7441E-06 S8 1.8819E-06 -1.0797E-02 8.0847E-03 -3.7453E-03 1.2868E-04 9.4428E-04 -6.3409E-04 S9 5.0756E-04 -1.8942E-02 1.4901E-02 -7.6969E-03 2.8356E-03 -7.5714E-04 1.4404E-04 S10 3.2190E-03 -1.7328E-02 1.2048E-02 -5.7309E-03 2.0079E-03 -5.2179E-04 9.9666E-05 S11 1.0275E-02 -1.0832E-02 8.4376E-03 -5.6908E-03 2.9065E-03 -1.1019E-03 3.0803E-04 S12 -3.3692E-02 8.4037E-03 -1.0065E-03 -2.3360E-04 1.4003E-04 -3.4225E-05 5.1522E-06 S13 -2.8349E-02 4.8770E-03 -1.2879E-03 3.1117E-04 -6.1124E-05 8.8629E-06 -9.1790E-07 S14 1.0845E-02 -7.6356E-03 2.0638E-03 -3.9383E-04 5.4302E-05 -5.4872E-06 4.1149E-07 S15 -6.1999E-03 1.3898E-03 -2.4272E-04 4.7078E-05 -6.9044E-06 7.0675E-07 -5.1442E-08 S16 -1.0936E-02 1.8838E-03 -3.4267E-04 5.1940E-05 -6.0004E-06 5.0229E-07 -2.9916E-08

[0126] Table 9-1

[0127] Face number A18 A20 A22 A24 A26 A28 A30 S1 3.8709E-08 -2.2818E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -3.6964E-07 1.5048E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -7.6056E-06 6.7637E-07 -2.5501E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 5.3732E-07 -8.3672E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 5.0921E-06 -2.9008E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 3.6259E-05 -4.4095E-06 2.3192E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 2.1365E-06 -2.0403E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 2.2413E-04 -4.8810E-05 6.5675E-06 -5.0275E-07 1.6804E-08 0.0000E+00 0.0000E+00 S9 -1.8438E-05 1.3920E-06 -3.7779E-08 -2.0210E-09 1.2994E-10 0.0000E+00 0.0000E+00 S10 -1.3695E-05 1.3061E-06 -8.1459E-08 2.9719E-09 -4.7905E-11 0.0000E+00 0.0000E+00 S11 -6.3269E-05 9.4836E-06 -1.0217E-06 7.6821E-08 -3.8186E-09 1.1258E-10 -1.4888E-12 S12 -5.0766E-07 3.2826E-08 -1.3506E-09 3.2375E-11 -3.4793E-13 0.0000E+00 0.0000E+00 S13 6.7769E-08 -3.5661E-09 1.3250E-10 -3.3919E-12 5.6849E-14 -5.6104E-16 2.4696E-18 S14 -2.3034E-08 9.5945E-10 -2.9324E-11 6.3876E-13 -9.3908E-15 8.3568E-17 -3.4028E-19 S15 2.7091E-09 -1.0358E-10 2.8448E-12 -5.4620E-14 6.9506E-16 -5.2612E-18 1.7915E-20 S16 1.2612E-09 -3.7335E-11 7.5914E-13 -1.0101E-14 7.9208E-17 -2.7752E-19 0.0000E+00

[0128] Table 9-2

[0129] Figure 6A The on-axis chromatic aberration curve of the optical imaging system of Embodiment 3 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 6B The astigmatism curves of the optical imaging system of Example 3 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 6C The distortion curves of the optical imaging system of Example 3 are shown, which represent the distortion magnitude values ​​corresponding to different image heights. Figure 6D The magnification chromatic aberration curve of the optical imaging system of Embodiment 3 is shown, which represents the deviation of different image heights on the imaging plane after light passes through the lens. According to Figures 6A to 6D It can be seen that the optical imaging system given in Example 3 can achieve good imaging quality.

[0130] In summary, Examples 1 to 3 satisfy the relationships shown in Tables 10-1, 10-2 and 10-3, respectively.

[0131]

[0132] Table 10-1

[0133]

[0134]

[0135] Table 10-2

[0136]

[0137] Table 10-3

[0138] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging system described above.

[0139] 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 comprising, sequentially from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, each having optical power, characterized in that, The first lens, the third lens, the fourth lens, and the seventh lens have positive optical power; The second lens, the fifth lens, the sixth lens, and the eighth lens have negative optical power; The object-side surface of the first lens, the second lens, the third lens, the fifth lens, and the seventh lens is convex, and the image-side surface is concave. The object-side surface of the fourth lens and the sixth lens is concave and the image-side surface is convex. The object-side surface of the eighth lens is concave, and the image-side surface is also concave. The optical imaging system has eight lenses with optical power. The optical power of any one of the first lens, the second lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens j satisfies: | j|>| 3| and| j|>| 4|, where j is selected from 1, 2, 5, 6, 7, 8; as well as The optical imaging system also includes: A second spacer element located between the second lens and the third lens; A third spacer element located between the third lens and the fourth lens; A fourth spacer element located between the fourth lens and the fifth lens; A fifth spacer element located between the fifth lens and the sixth lens; A sixth spacer element located between the sixth lens and the seventh lens; The seventh spacer element located between the seventh lens and the eighth lens; and The eighth spacer element is located on the image-side surface of the eighth lens, wherein, The optical imaging system satisfies: 5.84 ≤ f / (CT7+EP78-T67) ≤ 10.64 and 7.39 ≤ AVE(f3,f4) / D3m / ((EP23+EP34) / T34) ≤ 14.83, where f is the total effective focal length of the optical imaging system, CT7 is the center thickness of the seventh lens, EP78 is the spacing distance between the image side of the seventh spacer element and the object side of the eighth spacer element in the direction parallel to the optical axis, and T67 is the distance between the sixth lens and the seventh lens on the optical axis. Air gap, AVE(f3,f4) is the average of the effective focal length f3 of the third lens and the effective focal length f4 of the fourth lens, D3m is the outer diameter of the image side of the third spacer element, EP23 is the distance between the image side of the second spacer element and the object side of the third spacer element in the direction parallel to the optical axis, EP34 is the distance between the image side of the third spacer element and the object side of the fourth spacer element in the direction parallel to the optical axis, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

2. The optical imaging system according to claim 1, characterized in that, The optical imaging system satisfies: -14.57≤f6 / f7 / (CP6+CT7+CP7-T67)≤-4.14, where f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, CP6 is the maximum thickness of the sixth spacer element, and CP7 is the maximum thickness of the seventh spacer element.

3. The optical imaging system according to claim 1, characterized in that, The optical imaging system satisfies: 12.09≤d7s / (CT7+EP78)+d7m / (EP78+CT8)≤21.19, where d7s is the inner diameter of the object side of the seventh spacer element, d7m is the inner diameter of the image side of the seventh spacer element, and CT8 is the center thickness of the eighth lens.

4. The optical imaging system according to claim 1, characterized in that, The optical imaging system satisfies: 14.66≤f / CT6+(D6m-d6s) / (CT6+T67)≤18.04, where D6m is the outer diameter of the image side of the sixth spacer element, d6s is the inner diameter of the object side of the sixth spacer element, and CT6 is the center thickness of the sixth lens.

5. The optical imaging system according to claim 1, characterized in that, The optical imaging system satisfies: -9.30≤(R4+R7) / AVE(D2s,D3s)×((T23+T34) / EP23)≤-6.77, where AVE(D2s,D3s) is the average of the outer diameters D2s of the object side of the second spacer and D3s of the object side of the third spacer, EP23 is the distance between the image side of the second spacer and the object side of the third spacer in the direction parallel to the optical axis, T23 is the air gap between the second lens and the third lens on the optical axis, T34 is the air gap between the third lens and the fourth lens on the optical axis, R4 is the radius of curvature of the image side of the second lens, and R7 is the radius of curvature of the object side of the fourth lens.

6. The optical imaging system according to claim 1, characterized in that, The optical imaging system satisfies: 7.96≤D3s / (T34+EP34-CT4)≤11.21, where D3s is the outer diameter of the object side of the third spacer element, T34 is the air gap between the third lens and the fourth lens on the optical axis, EP34 is the distance between the image side of the third spacer element and the object side of the fourth spacer element in a direction parallel to the optical axis, and CT4 is the center thickness of the fourth lens.

7. The optical imaging system according to claim 1, characterized in that, The optical imaging system satisfies: 0.89≤(D(i+1)m-Dim) / EPi(i+1)≤6.01, where i is selected from 4, 5, and 6, where Dim is the outer diameter of the image-side surface of the i-th spacer element, D(i+1)m is the outer diameter of the image-side surface of the (i+1)-th spacer element, and EPi(i+1) is the distance between the image-side surface of the i-th spacer element and the object-side surface of the (i+1)-th spacer element in the direction parallel to the optical axis.

8. The optical imaging system according to claim 1, characterized in that, The optical imaging system further includes a first spacer element located between the first lens and the second lens. The optical imaging system satisfies: 10.36≤d1s / CT1×(CP1 / T12)≤14.75, where d1s is the inner diameter of the object side of the first spacer element, CP1 is the maximum thickness of the first spacer element, CT1 is the center thickness of the first lens, and T12 is the air gap between the first lens and the second lens on the optical axis.

9. The optical imaging system according to any one of claims 1-8, characterized in that, The optical imaging system further includes a lens barrel that houses the first lens to the eighth lens. The optical imaging system satisfies: 12.24≤D0m / (L-CT1)×(D0s / CT1)≤18.47, where L is the maximum thickness of the lens barrel, D0m is the outer diameter of the image side of the lens barrel, D0s is the outer diameter of the object side of the lens barrel, and CT1 is the center thickness of the first lens.

10. The optical imaging system according to claim 9, characterized in that, The optical imaging system satisfies: 28.78≤(d0m-d3s) / (d0s-d3s)×(EPD / T34)≤35.02, where d0m is the inner diameter of the image side of the lens barrel, d0s is the inner diameter of the object side of the lens barrel, d3s is the inner diameter of the object side of the third spacer element, EPD is the entrance pupil diameter of the optical imaging system, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

11. The optical imaging system according to claim 9, characterized in that, The optical imaging system further includes a first spacer element located between the first lens and the second lens. The optical imaging system satisfies: 0.94≤CP1 / (EP01-CT1)≤2.01, where CP1 is the maximum thickness of the first spacer element, CT1 is the center thickness of the first lens, and EP01 is the distance between the object side of the lens barrel and the object side of the first spacer element in a direction parallel to the optical axis.

12. The optical imaging system according to claim 9, characterized in that, The lens barrel is a one-piece lens barrel.

13. The optical imaging system according to claim 9, characterized in that, The lens barrel includes a first lens barrel that houses the first lens and a second lens barrel that houses the second lens to the eighth lens, wherein the first lens and the second lens barrel are fixed together by adhesive material.

Images