Optical imaging system

Abstract

This application discloses an optical imaging system, comprising: an imaging lens group consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side; wherein the first lens has positive optical power; the second lens has negative optical power; the third and fourth lenses have different signs of optical power; the fifth lens has positive optical power; the sixth lens has negative optical power; at least one of the object side and image side of the sixth lens has an inflection point; and the Abbe number of both the second and fourth lenses is less than 25; a plurality of spacer elements including a third spacer element and a fourth spacer element; and a lens barrel; wherein the radius of curvature R9 of the object side of the fifth lens, the spacing EP34 of the image side and object side of the third spacer element along the optical axis, and the maximum thickness CP4 of the fourth spacer element along the optical axis satisfy: 11 <R9 / (EP34+CP4)<33。

Description

[0001] Divisional application statement

[0002] This application is a divisional application of Chinese invention patent application filed on September 15, 2022, entitled "Optical Imaging System" and with application number 202211123589.5. Technical Field

[0003] This application relates to the field of optical components, and more specifically, to an optical imaging system. Background Technology

[0004] In recent years, with the widespread use of mobile phones in daily life, people have not only placed higher demands on the image quality of mobile phone lenses, but also paid more attention to the appearance of the lenses. As a result, ultra-thin, large-aperture mobile phone lenses have gradually become an industry trend. However, ultra-thin, large-aperture lenses often have limitations in the size of the lens barrel, especially for multi-element imaging lenses, which present significant design challenges. For example, for 6P ultra-thin, large-aperture, large-aperture imaging lenses, the overall lens barrel is relatively thin, and the gap between the last two lens elements is large, resulting in significant discontinuity. This can easily affect the performance of the imaging system, and the light-gathering ability needs to be further enhanced. At the same time, when the discontinuity of the imaging lens is large, assembly instability can easily occur, thus affecting the overall quality of the lens.

[0005] Therefore, while meeting customers' requirements for the appearance and overall size of the lens, how to improve the assembly stability and stray light problem of lenses with large gaps, so as to make the lens have good image quality, is one of the key research topics for designers. Summary of the Invention

[0006] This application provides an optical imaging system comprising: an imaging lens group consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side; wherein the first lens has positive optical power, the third and fourth lenses have optical power with different signs, the fifth lens has positive optical power, the sixth lens has negative optical power, at least one of the object side and the image side of the sixth lens has an inflection point, and the Abbe number of the second and fourth lenses is less than 25; A spacer element, including a third spacer element placed between a third lens and a fourth lens and in contact with the image side of the third lens, and a fifth spacer element placed between a fifth lens and a sixth lens and in contact with the image side of the fifth lens; and a lens barrel for accommodating the imaging lens group and the multiple spacer elements; the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, the maximum thickness CP3 of the third spacer element along the optical axis and the maximum thickness CP5 of the fifth spacer element along the optical axis satisfy: 0.7 < (f5 + f6) / (CP3 + CP5) < 11.

[0007] In one embodiment, the plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and contacting the image side of the first lens, a second spacer element disposed between the second lens and the third lens and contacting the image side of the second lens, and a fourth spacer element disposed between the fourth lens and the fifth lens and contacting the image side of the fourth lens. The optical imaging system satisfies 0.5 < Dim / TD < 2.0, where Dim is the outer diameter of the image side of the spacer element of the lens with an Abbe number greater than 50 in the imaging lens group, and TD is the distance on the optical axis from the object side of the first lens to the image side of the sixth lens; when i = 1, D1m represents the outer diameter of the image side of the first spacer element; when i = 2, D2m represents the outer diameter of the image side of the second spacer element; when i = 3, D3m represents the outer diameter of the image side of the third spacer element; when i = 4, D4m represents the outer diameter of the image side of the fourth spacer element; and when i = 5, D5m represents the outer diameter of the image side of the fifth spacer element.

[0008] In one embodiment, the plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and contacting the image side of the first lens, a second spacer element disposed between the second lens and the third lens and contacting the image side of the second lens, and a fourth spacer element disposed between the fourth lens and the fifth lens and contacting the image side of the fourth lens. The optical imaging system satisfies 1 < f / djm < 3, where f is the effective focal length of the optical imaging system, and djm is the inner diameter of the image side of the spacer element of the lens with a negative optical power in the imaging lens group; when j = 1, d1m represents the inner diameter of the image side of the first spacer element; when j = 2, d2m represents the inner diameter of the image side of the second spacer element; when j = 3, d3m represents the inner diameter of the image side of the third spacer element; when j = 4, d4m represents the inner diameter of the image side of the fourth spacer element; and when j = 5, d5m represents the inner diameter of the image side of the fifth spacer element.

[0009] In one embodiment, the plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and contacting the image side of the first lens; the combined focal length f12 of the first lens and the second lens, the distance EP01 along the optical axis between the front end face of the lens barrel near the object side and the object side of the first spacer element, and the maximum thickness CP1 of the first spacer element along the optical axis satisfy 4 < f12 / (EP01 + CP1) < 8.

[0010] In one embodiment, the plurality of spacers further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens, and a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens; wherein the radius of curvature R3 of the object-side surface of the second lens, the radius of curvature R4 of the image-side surface of the second lens, the inner diameter d1m of the image-side surface of the first spacer element and the inner diameter d2s of the object-side surface of the second spacer element satisfy: 9<(R3×R4) / (d1m×d2s)<34.

[0011] In one embodiment, at least two of the first to third lenses are meniscus lenses in the paraxial region.

[0012] In one embodiment, the radius of curvature R2 of the image-side surface of the first lens and the radius of curvature R12 of the image-side surface of the sixth lens satisfy: R2>R12.

[0013] In one embodiment, the plurality of spacers further includes a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens, wherein the combined focal length f23 of the second lens and the third lens and the inner diameter d2m of the image-side surface of the second spacer element satisfy: 4 < |f23| / d2m < 12.

[0014] In one embodiment, the combined focal length f34 of the third lens and the fourth lens, the outer diameter D3s of the object side of the third spacer element, and the outer diameter D3m of the image side of the third spacer element satisfy: 3<|f34| / (D3s+D3m)<24.

[0015] In one embodiment, the plurality of spacers further includes a fourth spacer element disposed between the fourth lens and the fifth lens and in contact with the image side of the fourth lens, wherein the effective focal length f4 of the fourth lens, the inner diameter d4s of the object side of the fourth spacer element and the outer diameter D4s of the object side of the fourth spacer element satisfy: 1<|f4| / (d4s+D4s)<18.

[0016] In one embodiment, the plurality of spacers further includes a fourth spacer element disposed between the fourth lens and the fifth lens and in contact with the image-side surface of the fourth lens, wherein the radius of curvature R9 of the object-side surface of the fifth lens, the spacing EP34 between the image-side surface of the third spacer element and the object-side surface of the fourth spacer element along the optical axis, and the maximum thickness CP4 of the fourth spacer element along the optical axis satisfy: 11 <R9 / (EP34+CP4)<33。

[0017] In one embodiment, the plurality of spacers further includes a fourth spacer element disposed between the fourth lens and the fifth lens and in contact with the image-side surface of the fourth lens, wherein the radius of curvature R10 of the image-side surface of the fifth lens, the radius of curvature R11 of the object-side surface of the sixth lens, and the spacing EP45 of the image-side surface of the fourth spacer element and the object-side surface of the fifth spacer element along the optical axis satisfy: -13<(R10+R11) / EP45<-5.

[0018] In one embodiment, the inner diameter d5s of the object side of the fifth spacer element, the inner diameter d5m of the image side of the fifth spacer element, and the air gap T56 between the fifth lens and the sixth lens on the optical axis satisfy: 23 < (d5s + d5m) / T56 < 32.

[0019] In one embodiment, the inner diameter d0s of the front end face of the lens barrel near the object side, the outer diameter D0s of the front end face of the lens barrel near the object side, and the entrance pupil diameter EPD of the optical imaging system satisfy: 2<(d0s+D0s) / EPD<5.

[0020] In one embodiment, the plurality of spacers further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens, and a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens; wherein the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the spacing EP12 between the image-side surface of the first spacer element and the object-side surface of the second spacer element along the optical axis, and the spacing EP23 between the image-side surface of the second spacer element and the object-side surface of the third spacer element along the optical axis satisfy: 6<|f1+f2| / (EP12+EP23)<18.

[0021] This application also provides an optical imaging system comprising: an imaging lens group consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side, wherein the first lens has positive optical power, the second lens has negative optical power, the optical powers of the third and fourth lenses have different signs, the optical powers of the fifth and sixth lenses have different signs, the object side and image side of the sixth lens both have inflection points, and the refractive indices of the second and fourth lenses are both greater than 1.6; multiple spacer elements, including a third spacer element placed between the third and fourth lenses and in contact with the image side of the third lens, and a fourth spacer element placed between the fourth and fifth lenses and in contact with the image side of the fourth lens; and a lens barrel for accommodating the imaging lens group and the multiple spacer elements; wherein the radius of curvature R9 of the object side of the fifth lens, the spacing EP34 of the image side and object side of the fourth spacer element along the optical axis, and the maximum thickness CP4 of the fourth spacer element along the optical axis satisfy: 11 <R9 / (EP34+CP4)<33。

[0022] This application also provides an optical imaging system comprising: an imaging lens group consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side; wherein the first lens has positive optical power, and both its object-side and image-side radii of curvature are positive; the second lens has negative optical power, and both its object-side and image-side radii of curvature are positive; the third and fourth lenses have different signs of optical power, with the third lens having a positive object-side radius of curvature; the fourth lens having a positive image-side radius of curvature; the fifth lens having positive optical power, with a positive object-side radius of curvature and a negative image-side radius of curvature; and the sixth lens having negative optical power. At least one of the object-side and image-side surfaces of the lens has an inflection point; the radius of curvature of the object-side surface of the sixth lens is negative, and the radius of curvature of the image-side surface is positive; and the Abbe numbers of the second and fourth lenses are both less than 25; multiple spacer elements, including a third spacer element placed between the third and fourth lenses and in contact with the image-side surface of the third lens, and a fourth spacer element placed between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens; and a lens barrel for accommodating the imaging lens group and the multiple spacer elements; the radius of curvature R9 of the object-side surface of the fifth lens, the spacing EP34 of the image-side surface of the third spacer element and the object-side surface of the fourth spacer element along the optical axis, and the maximum thickness CP4 of the fourth spacer element along the optical axis satisfy: 11 <R9 / (EP34+CP4)<33。

[0023] In one embodiment, the plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and in contact with the image side of the first lens, a second spacer element disposed between the second lens and the third lens and in contact with the image side of the second lens, and a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image side of the fifth lens. wherein, the optical imaging system satisfies: 0.5 < Dim / TD < 2.0, where Dim is the outer diameter of the image side of the spacer element of the lens with an Abbe number greater than 50 in the imaging lens group, and TD is the distance on the optical axis from the object side of the first lens to the image side of the sixth lens; when i = 1, D1m represents the outer diameter of the image side of the first spacer element; when i = 2, D2m represents the outer diameter of the image side of the second spacer element; when i = 3, D3m represents the outer diameter of the image side of the third spacer element; when i = 4, D4m represents the outer diameter of the image side of the fourth spacer element; and when i = 5, D5m represents the outer diameter of the image side of the fifth spacer element.

[0024] In one embodiment, the plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and in contact with the image side of the first lens, a second spacer element disposed between the second lens and the third lens and in contact with the image side of the second lens, and a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image side of the fifth lens. wherein, the optical imaging system satisfies: 1 < f / djm < 3, where f is the effective focal length of the optical imaging system, and djm is the inner diameter of the image side of the spacer element of the lens with a negative optical power in the imaging lens group; when j = 1, d1m represents the inner diameter of the image side of the first spacer element; when j = 2, d2m represents the inner diameter of the image side of the second spacer element; when j = 3, d3m represents the inner diameter of the image side of the third spacer element; when j = 4, d4m represents the inner diameter of the image side of the fourth spacer element; and when j = 5, d5m represents the inner diameter of the image side of the fifth spacer element.

[0025] In one embodiment, the plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and in contact with the image side of the first lens; wherein, the combined focal length f12 of the first lens and the second lens, the distance EP01 along the optical axis between the front end face of the lens barrel near the object side and the object side of the first spacer element, and the maximum thickness CP1 of the first spacer element along the optical axis satisfy: 4 < f12 / (EP01 + CP1) < 8.

[0026] In one embodiment, the plurality of spacers further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens, and a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens; wherein the radius of curvature R3 of the object-side surface of the second lens, the radius of curvature R4 of the image-side surface of the second lens, the inner diameter d1m of the image-side surface of the first spacer element and the inner diameter d2s of the object-side surface of the second spacer element satisfy: 9<(R3×R4) / (d1m×d2s)<34.

[0027] In one embodiment, at least two of the first to third lenses are meniscus lenses in the paraxial region.

[0028] In one embodiment, the radius of curvature R2 of the image-side surface of the first lens and the radius of curvature R12 of the image-side surface of the sixth lens satisfy: R2>R12.

[0029] In one embodiment, the plurality of spacers further includes a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens, wherein the combined focal length f23 of the second lens and the third lens and the inner diameter d2m of the image-side surface of the second spacer element satisfy: 4 < |f23| / d2m < 12.

[0030] In one embodiment, the combined focal length f34 of the third lens and the fourth lens, the outer diameter D3s of the object side of the third spacer element, and the outer diameter D3m of the image side of the third spacer element satisfy: 3<|f34| / (D3s+D3m)<24.

[0031] In one embodiment, the effective focal length f4 of the fourth lens, the inner diameter d4s of the object side of the fourth spacer element, and the outer diameter D4s of the object side of the fourth spacer element satisfy: 1<|f4| / (d4s+D4s)<18.

[0032] In one embodiment, the plurality of spacers further includes a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image side of the fifth lens, wherein the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, the maximum thickness CP3 of the third spacer element along the optical axis and the maximum thickness CP5 of the fifth spacer element along the optical axis satisfy: 0.7 < (f5 + f6) / (CP3 + CP5) < 11.

[0033] In one embodiment, the plurality of spacers further includes a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image-side surface of the fifth lens, wherein the radius of curvature R10 of the image-side surface of the fifth lens, the radius of curvature R11 of the object-side surface of the sixth lens, and the spacing EP45 of the image-side surface of the fourth spacer element and the object-side surface of the fifth spacer element along the optical axis satisfy: -13<(R10+R11) / EP45<-5.

[0034] In one embodiment, the plurality of spacers further includes a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image side of the fifth lens, wherein the inner diameter d5s of the object side of the fifth spacer element, the inner diameter d5m of the image side of the fifth spacer element, and the air gap T56 between the fifth lens and the sixth lens on the optical axis satisfy: 23<(d5s+d5m) / T56<32.

[0035] In one embodiment, the inner diameter d0s of the front end face of the lens barrel near the object side, the outer diameter D0s of the front end face of the lens barrel near the object side, and the entrance pupil diameter EPD of the optical imaging system satisfy: 2<(d0s+D0s) / EPD<5.

[0036] In one embodiment, the plurality of spacers further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens, and a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens; wherein the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the spacing EP12 between the image-side surface of the first spacer element and the object-side surface of the second spacer element along the optical axis, and the spacing EP23 between the image-side surface of the second spacer element and the object-side surface of the third spacer element along the optical axis satisfy: 6<|f1+f2| / (EP12+EP23)<18.

[0037] The optical imaging system provided in this application is a six-element lens with a large step difference. On the one hand, by rationally configuring the optical power and partial surface shape of each lens, ultra-thin lenses can be achieved under the premise of good manufacturing feasibility, providing greater flexibility for the shape design of electronic devices such as mobile phones. By controlling the Abbe number of the second and fourth lenses to be less than 25, the light direction of the optical imaging system can be effectively guaranteed, reducing the risk of stray light generation while balancing dispersion. Furthermore, by setting spacers between the lenses, stray light can be improved, and the optical imaging system can meet the requirements of assembly stability and reliability.

[0038] The optical imaging system provided by this application is a six-piece lens with a large step difference. By controlling the effective focal lengths of the fifth lens and the sixth lens, it is beneficial to ensure that more light enters the image plane, and it is also beneficial to control the total length of the lens, ensuring that the lens meets the requirements of being ultra-thin and miniaturized. Then, according to the intervals of the optical imaging system, the thicknesses of the third spacer element and the fifth spacer element are selected to reasonably optimize the system structure, ensuring the overall strength of the lens and making the lens meet the requirements of assembly and reliability.

[0039] The optical imaging system provided by this application is a six-piece lens with a large step difference. By controlling the curvature radius of the object side surface of the fifth lens, the profile of the object side surface of the fifth lens is improved. By controlling the interval EP34 along the optical axis between the image side surface of the third spacer element and the object side surface of the fourth spacer element, the edge thickness of the fourth lens is optimized, thereby effectively preventing internal reflection stray light reflected from the edge of the fifth lens to the fourth lens. Further, by adjusting the thickness of the fourth spacer element, while ensuring the wall thickness, it is beneficial to ensure the stability of the assembly interval between the fourth lens and the fifth lens, and it is also beneficial to adjust the field curvature and improve the yield rate.

[0040] The optical imaging system according to this application satisfies: 11 < R9 / (EP34 + CP4) < 33, where R9 is the curvature radius of the object side surface of the fifth lens, EP34 is the interval along the optical axis between the image side surface of the third spacer element and the object side surface of the fourth spacer element, and CP4 is the maximum thickness of the fourth spacer element along the optical axis. Satisfying 11 < R9 / (EP34 + CP4) < 33 is beneficial to meet the requirements of ensuring the assembly stability of the lens. The curvature radius R9 of the object side surface of the fifth lens determines the profile of the object side surface of the fifth lens. The interval EP34 along the optical axis between the image side surface of the third spacer element and the object side surface of the fourth spacer element determines the edge thickness of the fourth lens, which can effectively prevent internal reflection stray light reflected from the edge of the fifth lens to the fourth lens. The fourth spacer element uses a plastic spacer ring, which is beneficial to have high processing accuracy and stable assembly interval while ensuring the wall thickness. It can also adjust the field curvature by adjusting the thickness of the fourth spacer element to improve the yield rate. Brief Description of the Drawings

[0041] By reading the detailed description of the non-restrictive embodiments made with reference to the following drawings, other features, purposes, and advantages of this application will become more obvious:

[0042] Figure 1 Shows the structural layout diagram of an optical imaging system according to this application and a schematic diagram of some parameters;

[0043] Figures 2A to 2C Shows the structural schematic diagram of the optical imaging system according to Embodiment 1 of this application;

[0044] Figures 3A to 3CThe on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system according to Embodiment 1 of this application are shown respectively.

[0045] Figures 4A to 4C A schematic diagram of the structure of an optical imaging system according to Embodiment 2 of this application is shown;

[0046] Figures 5A to 5C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system according to Embodiment 2 of this application are shown respectively.

[0047] Figures 6A to 6C A schematic diagram of the structure of an optical imaging system according to Embodiment 3 of this application is shown; and

[0048] Figures 7A to 7C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical imaging system according to Embodiment 3 of this application are shown. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In this article, curvature or paraxial curvature refers to the curvature of the region near the optical axis. If the curvature of a lens surface is positive and its location is not defined, it means that the curvature of the lens surface is positive at least in the paraxial region; if the curvature of a lens surface is negative and its location is not defined, it means that the curvature of the lens surface is negative 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.

[0053] 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.

[0054] 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.

[0055] 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 to sixth lenses), lens barrel structures, 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 combined only with the lens barrel structure, spacer elements, etc. of that embodiment.

[0056] 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 diagrams 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 air gap T56 between the fifth and sixth lenses on the optical axis, are not shown. Figure 1 As shown in the figure, Figure 1 The present application only exemplarily illustrates some parameters of the lens barrel and spacer element of an optical imaging system to facilitate a better understanding of the invention. Figure 1As 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; CP5 represents the maximum thickness of the fifth spacer element along the optical axis; 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; D0s represents the outer diameter of the front end face of the lens barrel near the object side; d0s represents the inner diameter of the front end face of the lens barrel near the object side; D5m represents the outer diameter of the image side face of the fifth spacer element; d5m represents the inner diameter of the image side face of the fifth spacer element; D0m represents the outer diameter of the rear end face of the lens barrel near the image side; d0m represents the inner diameter of the rear end face of the lens barrel near the image side.

[0057] The features, principles and other aspects of this application are described in detail below.

[0058] An optical imaging system according to an exemplary embodiment of this application includes an imaging lens group and multiple spacer elements. The imaging lens group, along the optical axis from the object side to the image side, sequentially includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens has positive optical power, the second lens has either positive or negative optical power, the third lens has either positive or negative optical power, the fourth lens has either positive or negative optical power, the fifth lens has positive optical power, and the sixth lens has negative optical power. The third and fourth lenses have different signs of optical power, and the sixth lens has at least one inflection point on either the object side or the image side. Furthermore, the Abbe numbers of both the second and fourth lenses are less than 25. By rationally configuring the optical power and surface shape of each lens, ultra-thin lenses can be achieved while maintaining good manufacturing feasibility, providing greater flexibility for the design of mobile phones and other electronic devices. Controlling the Abbe numbers of the second and fourth lenses to be less than 25 effectively ensures the light path of the optical imaging system, reducing the risk of stray light generation while balancing dispersion.

[0059] In an exemplary embodiment, the optical imaging system further includes a lens barrel for housing an imaging lens group and a plurality of spacer elements.

[0060] In an exemplary embodiment, at least two of the first to third lenses are meniscus lenses. More specifically, at least two of the first to third lenses are meniscus lenses in the paraxial region. Lenses of different shapes have different focal lengths and different light processing effects. An imaging lens group is a superposition of different lens surfaces. By superimposing the focal lengths of different lens surfaces, a certain imaging effect is achieved. Meniscus lenses can stably increase the imaging size, effectively shorten the overall lens length while ensuring good manufacturability, achieving ultra-thin characteristics and meeting the imaging requirements of the lens, thus improving image quality.

[0061] In an exemplary embodiment, the plurality of spacer elements may include a first spacer element disposed between a first lens and a second lens and in contact with the image-side surface of the first lens, a second spacer element disposed between a second lens and a third lens and in contact with the image-side surface of the second lens, a third spacer element disposed between a third lens and a fourth lens and in contact with the image-side surface of the third lens, a fourth spacer element disposed between a fourth lens and a fifth lens and in contact with the image-side surface of the fourth lens, and a fifth spacer element disposed between a fifth lens and a sixth lens and in contact with the image-side surface of the fifth lens.

[0062] 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.

[0063] In an exemplary embodiment, the optical imaging system according to this application satisfies: 0.7 < (f5 + f6) / (CP3 + CP5) < 11, where f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, CP3 is the maximum thickness of the third spacer element along the optical axis, and CP5 is the maximum thickness of the fifth spacer element along the optical axis. Satisfying 0.7 < (f5 + f6) / (CP3 + CP5) < 11 facilitates control of the optical power of the fifth and sixth lenses, ensuring more light enters the image plane. Furthermore, by selecting the thicknesses of the third and fifth spacers based on the spacing of the optical imaging system, the system structure is rationally optimized, ensuring the overall strength of the lens and enabling the lens to meet assembly and reliability requirements.

[0064] In an exemplary embodiment, the optical imaging system according to the present application may satisfy: 0.5 < Dim / TD < 2.0, where Dim is the outer diameter of the image side of the spacer element on the image side of the lens with an Abbe number greater than 50 in the imaging lens group; TD is the distance on the optical axis from the object side of the first lens to the image side of the sixth lens; Exemplarily, when i = 1, D1m represents the outer diameter of the image side of the first spacer element; when i = 2, D2m represents the outer diameter of the image side of the second spacer element; when i = 3, D3m represents the outer diameter of the image side of the third spacer element; when i = 4, D4m represents the outer diameter of the image side of the fourth spacer element; when i = 5, D5m represents the outer diameter of the image side of the fifth spacer element. Since it is necessary to control the overall chromatic aberration of the lens in the early stage of the design of the optical imaging system, materials with low refractive index and high Abbe number are reasonably selected. The optical imaging system according to the present application satisfies 0.5 < Dim / TD < 2.0, which can ensure the overall height of the lens, save costs while ensuring performance, reduce the overall space, and well meet the characteristics of the ultra-thin large image plane lens.

[0065] In an exemplary embodiment, the optical imaging system according to the present application may satisfy: 1 < f / djm < 3, where f is the effective focal length of the optical imaging system, and djm is the inner diameter of the image side of the spacer element on the image side of the lens with a negative optical power in the imaging lens group; Exemplarily, when j = 1, d1m represents the inner diameter of the image side of the first spacer element; when j = 2, d2m represents the inner diameter of the image side of the second spacer element; when j = 3, d3m represents the inner diameter of the image side of the third spacer element; when j = 4, d4m represents the inner diameter of the image side of the fourth spacer element; and when j = 5, d5m represents the inner diameter of the image side of the fifth spacer element. Satisfying 1 < f / djm < 3 can effectively control the steepness of the light rays, ensure the stability of the optical parameters of the lens, and effectively improve the stray light of the lens and improve the imaging quality.

[0066] In an exemplary embodiment, the optical imaging system according to the present application may satisfy: 4 < f12 / (EP01 + CP1) < 8, where f12 is the combined focal length of the first lens and the second lens, EP01 is the distance along the optical axis between the front end face of the lens barrel near the object side and the object side face of the first spacer element, and CP1 is the maximum thickness of the first spacer element along the optical axis. Satisfying 4 < f12 / (EP01 + CP1) < 8, by controlling the distance EP01 along the optical axis between the front end face of the lens barrel near the object side and the object side face of the first spacer element, it is beneficial to ensure the wall thickness at the front end of the lens barrel and the edge thickness of the first lens. The thicker the wall thickness at the front end of the lens barrel, the more beneficial it is for the molding of the lens barrel. The filling of the aperture will be full, and the risk of flocculent stray light in the lens barrel will be lower. Secondly, the combined focal length of the first lens and the second lens and the edge thickness of the first lens directly affect its molding. Since the first lens is a key part of the entire lens, good processability of the first lens is more beneficial to the overall performance of the lens. By selecting different thicknesses of CP1 during the trial production process, the field curvature can be optimized and the performance yield can be improved.

[0067] In an exemplary embodiment, the optical imaging system according to the present application may satisfy: 9 < (R3 × R4) / (d1m × d2s) < 34, where R3 is the curvature radius of the object side face of the second lens, R4 is the curvature radius of the image side face of the second lens, d1m is the inner diameter of the image side face of the first spacer element, and d2s is the inner diameter of the object side face of the second spacer element. Satisfying 9 < (R3 × R4) / (d1m × d2s) < 34, by controlling the curvature radii of the object side face and the image side face of the second lens, the processability of the second lens can be ensured. Additionally, by controlling the inner diameter of the image side face of the first spacer element and the inner diameter of the object side face of the second spacer element, the risk of internal reflection stray light on the inner diameter surfaces of the first spacer element and the second spacer element can be reduced, the stray light state can be improved, and the imaging quality can be enhanced.

[0068] In an exemplary embodiment, the optical imaging system according to the present application may satisfy: R2 > R12, where R2 is the curvature radius of the image side face of the first lens, and R12 is the curvature radius of the image side face of the sixth lens. More specifically, R2 and R12 may further satisfy: R2 > R12 > 0. Satisfying R2 > R12, by controlling the relationship between the curvature radii of the image side faces of the first lens and the sixth lens, it is beneficial to optimize the shapes of the first lens and the sixth lens and improve the processing manufacturability of the first lens and the sixth lens.

[0069] In an exemplary embodiment, the optical imaging system according to this application satisfies: 4 < |f23| / d2m < 12, where f23 is the combined focal length of the second and third lenses, and d2m is the inner diameter of the image-side surface of the second spacer element. By satisfying 4 < |f23| / d2m < 12 and controlling the ratio of the combined focal length f23 of the second and third lenses to the inner diameter d2m of the image-side surface of the second spacer element, the relative illumination of the optical parameters can be effectively guaranteed to meet customer requirements, and the risk of stray light reflected from the inner diameter surface can be reduced.

[0070] In an exemplary embodiment, the optical imaging system according to this application satisfies: 3 < |f34| / (D3s+D3m) < 24, where f34 is the combined focal length of the third and fourth lenses, D3s is the outer diameter of the object-side surface of the third spacer element, and D3m is the outer diameter of the image-side surface of the third spacer element. Satisfying 3 < |f34| / (D3s+D3m) < 24 effectively ensures the manufacturability of the lens profiles of the third and fourth lenses by controlling the combined focal length f34 of the third and fourth lenses. By controlling the outer diameters of the object-side and image-side surfaces of the third spacer element, the outer diameters of the third and fourth lenses can be essentially locked, thus controlling the overall uniformity of the lenses and ensuring surface stability.

[0071] In an exemplary embodiment, the optical imaging system according to this application satisfies: 1 < |f4| / (d4s+D4s) < 18, where f4 is the effective focal length of the fourth lens, d4s is the inner diameter of the object-side surface of the fourth spacer element, and D4s is the outer diameter of the object-side surface of the fourth spacer element. Satisfying 1 < |f4| / (d4s+D4s) < 18, by controlling the ratio of the effective focal length f4 of the fourth lens to the inner and outer diameters of the object-side surface of the fourth spacer element, the assembly of the optical imaging lens and the need to improve stray light can be guaranteed. Due to the influence of the thickness of the raw material of the spacer element, the more complex the required spacer element structure, the more complex the stray light state. The inner and outer diameters d4s and D4s of the object-side surface of the fourth spacer element that satisfy the condition 1 < |f4| / (d4s+D4s) < 18 determine the contact area between the spacer element and the fourth lens; the larger the contact area, the more stable the assembled structure.

[0072] In an exemplary embodiment, the optical imaging system according to the present application can satisfy: 11 < R9 / (EP34 + CP4) < 33, where R9 is the radius of curvature of the object side surface of the fifth lens, EP34 is the distance between the image side surface of the third spacer element and the object side surface of the fourth spacer element along the optical axis direction, and CP4 is the maximum thickness of the fourth spacer element along the optical axis direction. Satisfying 11 < R9 / (EP34 + CP4) < 33 is beneficial to meet the requirement of ensuring the lens assembly stability. The radius of curvature R9 of the object side surface of the fifth lens determines the profile of the object side surface of the fifth lens. The distance EP34 between the image side surface of the third spacer element and the object side surface of the fourth spacer element along the optical axis determines the edge thickness of the fourth lens, which can effectively prevent the internal stray light reflected from the edge of the fifth lens to the fourth lens. The fourth spacer element uses a plastic spacer ring, which is beneficial to have high processing accuracy and stable assembly spacing while ensuring the wall thickness. Also, the field curvature can be adjusted by adjusting the thickness of the fourth spacer element, improving the yield rate.

[0073] In an exemplary embodiment, the optical imaging system according to the present application can satisfy: -13 < (R10 + R11) / EP45 < -5, where R10 is the radius of curvature of the image side surface of the fifth lens, R11 is the radius of curvature of the object side surface of the sixth lens, and EP45 is the distance between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element along the optical axis direction. Satisfying -13 < (R10 + R11) / EP45 < -5 is beneficial to control the incident angle of off-axis field light on the imaging surface by controlling the radii of curvature of the image side surface of the fifth lens and the object side surface of the sixth lens, increasing the matching with the photosensitive element and the band-pass filter; in addition, by controlling the distance between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element along the optical axis direction, the edge thickness of the fifth lens can be ensured. This condition is also beneficial to control the thickness ratio and surface shape of the last two lenses, ensuring good processing feasibility of the last two lenses.

[0074] In an exemplary embodiment, the optical imaging system according to the present application can satisfy: 23 < (d5s + d5m) / T56 < 32, where d5s is the inner diameter of the object side surface of the fifth spacer element, d5m is the inner diameter of the image side surface of the fifth spacer element, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis. The fifth spacer element is between the fifth lens and the sixth lens, and it is exactly at the position with the largest step difference in the large image plane model. Therefore, satisfying 23 < (d5s + d5m) / T56 < 32, the inner diameter inclined surface angle of the fifth spacer element is controlled by the inner diameters of the image side surface and the object side surface of the fifth spacer element, effectively avoiding the stray light reflected from the filter at this position. In addition, in order to stabilize the air gap T56 between the fifth lens and the sixth lens on the optical axis, the fifth spacer element at this position is a plastic spacer ring, and the method of auxiliary support with the lens barrel is adopted, which is beneficial to reducing the stability of the gap.

[0075] In an exemplary embodiment, the optical imaging system according to this application satisfies: 2 < (d0s + D0s) / EPD < 5, where d0s is the inner diameter of the front end face of the lens barrel near the object side, D0s is the outer diameter of the front end face of the lens barrel near the object side, and EPD is the entrance pupil diameter of the optical imaging system. Satisfying 2 < (d0s + D0s) / EPD < 5, controlling the inner and outer diameters of the front end face of the lens barrel ensures the assembly support length; a longer length results in better assembly stability. Furthermore, the selection of the entrance pupil position effectively ensures that optical performance requirements are met and avoids the risk of stray light caused by the thickness of the lens barrel at the exit aperture.

[0076] In an exemplary embodiment, the optical imaging system according to this application satisfies: 6 < |f1 + f2| / (EP12 + EP23) < 18, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, EP12 is the distance between the image-side surface of the first spacer element and the object-side surface of the second spacer element along the optical axis, and EP23 is the distance between the image-side surface of the second spacer element and the object-side surface of the third spacer element along the optical axis. Satisfying 6 < |f1 + f2| / (EP12 + EP23) < 18 ensures that the effective focal lengths f1 and f2 of the first and second lenses maintain their edge curvature, effectively reducing the risk of light leakage at the effective diameter edge. The distance between the image-side surface of the first spacer element and the object-side surface of the second spacer element along the optical axis (EP12) and the distance between the image-side surface of the second spacer element and the object-side surface of the third spacer element along the optical axis (EP23) can affect the edge thickness of the second and third lenses. Ensuring the uniformity of the thickness of the first three lenses and guaranteeing the strength and processing precision of the mold are prerequisites for improving lens performance yield.

[0077] In exemplary embodiments, the optical imaging system described above may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface. The optical imaging system according to the above embodiments of this application may employ multiple lenses, such as the six lenses mentioned above. By rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis spacing between lenses, 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.

[0078] In embodiments of this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface; that is, at least one mirror surface from the object-side surface of the first lens to the image-side surface of the sixth lens is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from the lens center to the lens periphery. Unlike a spherical lens, which has a constant curvature from the lens center to the lens periphery, an aspherical lens has better curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. Optionally, the object-side surface and image-side surface of each of the first, second, third, fourth, fifth, and sixth lenses are both aspherical mirror surfaces.

[0079] Specific embodiments of the optical imaging system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0080] Example 1

[0081] The following is for reference Figures 2A to 3C The optical imaging system 1001, optical imaging system 1002 and optical imaging system 1003 according to Embodiment 1 of this application are described. Figures 2A to 2C Schematic diagrams of optical imaging systems 1001, 1002 and 1003 according to Embodiment 1 of this application are shown respectively.

[0082] like Figures 2A to 2C As shown, optical imaging systems 1001, 1002 and 1003 each include a lens barrel P0, imaging lens groups E1 to E6 and multiple spacer elements P1 to P5.

[0083] like Figures 2A to 2CAs shown, optical imaging systems 1001, 1002, and 1003 employ the same imaging lens group, which, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. Specifically, the first lens E1 has positive optical power and has an object-side surface S1 and an image-side surface S2. The second lens E2 has negative optical power and has an object-side surface S3 and an image-side surface S4. The third lens E3 has negative optical power and has an object-side surface S5 and an image-side surface S6. The fourth lens E4 has positive optical power and has an object-side surface S7 and an image-side surface S8. The fifth lens E5 has positive optical power and has an object-side surface S9 and an image-side surface S10. The sixth lens E6 has negative optical power and has an object-side surface S11 and an image-side surface S12. The filter E7 (not shown) has an object side surface S13 (not shown) and an image side surface S14 (not shown). Light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15 (not shown).

[0084] Table 1 shows the basic parameters of the imaging lens groups of optical imaging systems 1001, 1002 and 1003 of Embodiment 1, wherein the units of radius of curvature, thickness and effective focal length are millimeters (mm).

[0085]

[0086]

[0087] Table 1

[0088] In this example, optical imaging systems 1001, 1002, and 1003 also have the following basic parameters: the distance TD between the object side of the first lens and the image side of the sixth lens on the optical axis is 5.185 mm; half the diagonal length ImgH of the effective pixel area on the imaging surface of the optical imaging system is 4.75 mm; the effective focal length f of the optical imaging system is 5.57 mm; and the entrance pupil diameter EPD of the optical imaging system is 3.01 mm.

[0089] In Embodiment 1, the object-side surface and image-side surface of the first lens E1 to the sixth lens E6 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:

[0090]

[0091] Where x is the distance vector from the vertex of the aspherical surface at a height 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. Table 2 gives the higher-order coefficients A4, A6, A8, A12 that can be used for each aspherical mirror S1-S12 in Example 1. 10 A 12 A 14 A 16 A 18 and A 20 .

[0092]

[0093] Table 2

[0094] like Figures 2A to 2C As shown, the optical imaging systems 1001, 1002, and 1003 each include a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5. Specifically, the first spacer element P1 is disposed between the first lens E1 and the second lens E2 and contacts the image-side surface of the first lens E1; the second spacer element P2 is disposed between the second lens E2 and the third lens E3 and contacts the image-side surface of the second lens E2; the third spacer element P3 is disposed between the third lens E3 and the fourth lens E4 and contacts the image-side surface of the third lens E3; the fourth spacer element P4 is disposed between the fourth lens E4 and the fifth lens E5 and contacts the image-side surface of the fourth lens E4; and the fifth spacer element P5 is disposed between the fifth lens E5 and the sixth lens E6 and contacts the image-side surface of the fifth lens E5. The aforementioned multiple spacer elements can block excess external light from entering, allowing the lens to better support the lens barrel and enhancing the structural stability of optical imaging systems 1001, 1002, and 1003.

[0095] Table 3 shows the basic parameters of the spacer elements and lens barrels of the optical imaging systems 1001, 1002 and 1003 of Embodiment 1. The unit of each parameter in Table 3 is millimeters (mm).

[0096] Example parameters Optical Imaging System 1001 Optical Imaging System 1002 Optical Imaging System 1003 d1m 2.779 2.795 2.770 D1m 4.102 4.402 4.816 d2s 2.403 2.429 2.382 d2m 2.403 2.429 2.382 d3m 3.041 2.978 2.818 D3s 5.381 4.816 6.288 D3m 5.381 4.816 6.288 d4s 4.351 4.126 4.046 d4m 4.351 4.126 4.046 D4s 7.278 7.278 7.198 d5s 6.493 6.340 6.469 d5m 7.333 7.330 7.356 D5m 7.815 7.936 7.834 d0s 4.108 4.216 4.271 D0s 5.508 5.906 5.508 EP01 1.050 1.028 1.028 CP1 0.018 0.018 0.022 EP12 0.552 0.574 0.568 EP23 0.396 0.358 0.352 CP3 0.016 0.018 0.030 EP34 0.564 0.600 0.588 CP4 0.037 0.037 0.037 EP45 0.583 0.557 0.557 CP5 0.472 0.463 0.425

[0097] Table 3

[0098] Figure 3A The on-axis chromatic aberration curves of optical imaging systems 1001, 1002 and 1003 of Embodiment 1 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 3B Astigmatism curves of optical imaging systems 1001, 1002 and 1003 of Embodiment 1 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 3C The distortion curves of optical imaging systems 1001, 1002, and 1003 of Embodiment 1 are shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figures 3A to 3C It can be seen that the optical imaging system 1001, optical imaging system 1002 and optical imaging system 1003 given in Example 1 can achieve good imaging quality.

[0099] Example 2

[0100] The following is for reference Figures 4A to 5C The optical imaging system 2001, optical imaging system 2002, and optical imaging system 2003 according to Embodiment 2 of this application are described. In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to those in Embodiment 1 will be omitted. Figures 4A to 4C Schematic diagrams of optical imaging systems 2001, 2002 and 2003 according to Embodiment 2 of this application are shown respectively.

[0101] like Figures 4A to 4C As shown, optical imaging systems 2001, 2002 and 2003 each include a lens barrel P0, imaging lens groups E1 to E6 and multiple spacer elements P1 to P5.

[0102] like Figures 4A to 4C As shown, optical imaging systems 2001, 2002, and 2003 employ the same imaging lens group, which, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. Specifically, the first lens E1 has positive optical power and has an object-side surface S1 and an image-side surface S2. The second lens E2 has negative optical power and has an object-side surface S3 and an image-side surface S4. The third lens E3 has positive optical power and has an object-side surface S5 and an image-side surface S6. The fourth lens E4 has negative optical power and has an object-side surface S7 and an image-side surface S8. The fifth lens E5 has positive optical power and has an object-side surface S9 and an image-side surface S10. The sixth lens E6 has negative optical power and has an object-side surface S11 and an image-side surface S12. The filter E7 (not shown) has an object side surface S13 (not shown) and an image side surface S14 (not shown). Light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15 (not shown).

[0103] In this example, optical imaging systems 2001, 2002, and 2003 also have the following basic parameters: the distance TD between the object side of the first lens and the image side of the sixth lens on the optical axis is 4.558 mm; half the diagonal length ImgH of the effective pixel area on the imaging surface of the optical imaging system is 4.75 mm; the effective focal length f of the optical imaging system is 4.65 mm; and the entrance pupil diameter EPD of the optical imaging system is 2.51 mm.

[0104] Table 4 shows the basic parameters of the imaging lens groups of optical imaging systems 2001, 2002, and 2003 in Embodiment 2, wherein the units of radius of curvature, thickness, and effective focal length are millimeters (mm). Table 5 shows 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.

[0105]

[0106]

[0107] Table 4

[0108]

[0109] Table 5

[0110] like Figures 4A to 4C As shown, the optical imaging systems 2001, 2002, and 2003 each include a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5. Specifically, the first spacer element P1 is disposed between the first lens E1 and the second lens E2 and contacts the image-side surface of the first lens E1; the second spacer element P2 is disposed between the second lens E2 and the third lens E3 and contacts the image-side surface of the second lens E2; the third spacer element P3 is disposed between the third lens E3 and the fourth lens E4 and contacts the image-side surface of the third lens E3; the fourth spacer element P4 is disposed between the fourth lens E4 and the fifth lens E5 and contacts the image-side surface of the fourth lens E4; and the fifth spacer element P5 is disposed between the fifth lens E5 and the sixth lens E6 and contacts the image-side surface of the fifth lens E5. The aforementioned multiple spacer elements can block excess external light from entering, allowing the lens to better support the lens barrel and enhancing the structural stability of optical imaging systems 2001, 2002, and 2003.

[0111] Table 6 shows the basic parameters of the spacer elements and lens barrels of optical imaging systems 2001, 2002 and 2003 of Embodiment 2. The unit of each parameter in Table 6 is millimeters (mm).

[0112] Example parameters Optical Imaging System 2001 Optical Imaging System 2002 Optical Imaging System 2003 d1m 2.322 2.353 2.343 D1m 3.928 3.713 4.204 d2s 2.169 2.162 2.123 d2m 2.169 2.162 2.123 d3m 2.471 2.535 2.511 D3s 4.308 4.296 5.310 D3m 4.308 4.296 5.310 d4s 3.868 3.823 3.701 d4m 3.868 3.823 3.701 D4s 7.375 6.778 6.656 d5s 5.907 5.907 5.948 d5m 6.901 6.927 6.846 D5m 7.504 7.530 7.392 d0s 3.799 3.783 3.819 D0s 6.011 5.482 5.127 EP01 0.894 0.881 0.964 CP1 0.018 0.018 0.019 EP12 0.379 0.370 0.351 EP23 0.410 0.406 0.374 CP3 0.018 0.018 0.030 EP34 0.567 0.592 0.567 CP4 0.030 0.037 0.037 EP45 0.429 0.452 0.494 CP5 0.463 0.433 0.504

[0113] Table 6

[0114] Figure 5A The on-axis chromatic aberration curves of optical imaging systems 2001, 2002 and 2003 of Embodiment 2 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 5B Astigmatism curves of optical imaging systems 2001, 2002 and 2003 of Embodiment 2 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 5C The distortion curves of optical imaging systems 2001, 2002, and 2003 of Embodiment 2 are shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figures 5A to 5C It can be seen that the optical imaging system 2001, optical imaging system 2002 and optical imaging system 2003 given in Example 2 can achieve good imaging quality.

[0115] Example 3

[0116] The following is for reference Figures 6A to 7C The optical imaging system 3001, optical imaging system 3002 and optical imaging system 3003 according to Embodiment 3 of this application are described. Figures 6A to 6B Schematic diagrams of optical imaging systems 3001, 3002 and 3003 according to Embodiment 3 of this application are shown respectively.

[0117] like Figures 6A to 6C As shown, optical imaging systems 3001, 3002 and 3003 each include a lens barrel P0, imaging lens groups E1 to E6 and multiple spacer elements P1 to P5.

[0118] like Figures 6A to 6CAs shown, optical imaging systems 3001, 3002, and 3003 employ the same imaging lens group, which, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. Specifically, the first lens E1 has positive optical power and has an object-side surface S1 and an image-side surface S2. The second lens E2 has negative optical power and has an object-side surface S3 and an image-side surface S4. The third lens E3 has positive optical power and has an object-side surface S5 and an image-side surface S6. The fourth lens E4 has negative optical power and has an object-side surface S7 and an image-side surface S8. The fifth lens E5 has positive optical power and has an object-side surface S9 and an image-side surface S10. The sixth lens E6 has negative optical power and has an object-side surface S11 and an image-side surface S12. The filter E7 (not shown) has an object side surface S13 (not shown) and an image side surface S14 (not shown). Light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15 (not shown).

[0119] In this example, optical imaging systems 3001, 3002, and 3003 also have the following basic parameters: the distance TD between the object side of the first lens and the image side of the sixth lens on the optical axis is 5.242 mm; half the diagonal length of the effective pixel area ImgH on the imaging surface of the optical imaging system is 4.74 mm; the effective focal length f of the optical imaging system is 5.24 mm; and the entrance pupil diameter EPD of the optical imaging system is 2.86 mm.

[0120] Table 7 shows the basic parameters of the imaging lens groups of optical imaging systems 3001, 3002, and 3003 in Embodiment 3, wherein the units of radius of curvature, thickness, and effective focal length are millimeters (mm). Table 8 shows 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.

[0121]

[0122] Table 7

[0123]

[0124]

[0125] Table 8

[0126] like Figures 6A to 6CAs shown, the optical imaging systems 3001, 3002, and 3003 each include a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5. Specifically, the first spacer element P1 is disposed between the first lens E1 and the second lens E2 and contacts the image-side surface of the first lens E1; the second spacer element P2 is disposed between the second lens E2 and the third lens E3 and contacts the image-side surface of the second lens E2; the third spacer element P3 is disposed between the third lens E3 and the fourth lens E4 and contacts the image-side surface of the third lens E3; the fourth spacer element P4 is disposed between the fourth lens E4 and the fifth lens E5 and contacts the image-side surface of the fourth lens E4; and the fifth spacer element P5 is disposed between the fifth lens E5 and the sixth lens E6 and contacts the image-side surface of the fifth lens E5. The aforementioned multiple spacer elements can block excess external light from entering, allowing the lens to better support the lens barrel and enhancing the structural stability of optical imaging systems 3001, 3002, and 3003.

[0127] Table 9 shows the basic parameters of the spacer elements and lens barrels of the optical imaging systems 3001, 3002 and 3003 of Embodiment 3. The unit of each parameter in Table 9 is millimeters (mm).

[0128]

[0129]

[0130] Table 9

[0131] Figure 7A The on-axis chromatic aberration curves of optical imaging systems 3001, 3002 and 3003 of Embodiment 3 are shown, which indicate the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 7B Astigmatism curves of optical imaging systems 3001, 3002 and 3003 of Embodiment 3 are shown, representing meridional image plane curvature and sagittal image plane curvature. Figure 7C The distortion curves of optical imaging systems 3001, 3002, and 3003 of Embodiment 3 are shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figures 7A to 7C It can be seen that the optical imaging system 3001, optical imaging system 3002 and optical imaging system 3003 given in Example 3 can achieve good imaging quality.

[0132] In summary, the optical imaging systems 1001, 1002, 1003, 2001, 2002, 2003, 3001, 3002 and 3003 of Examples 1 to 3 satisfy the relationships shown in Table 10.

[0133] Conditional / Optical Imaging System 1001 1002 1003 2001 2002 2003 3001 3002 3003 (f5+f6) / (CP3+CP5) 2.96 3.00 3.17 1.08 1.16 0.98 10.16 10.72 8.54 f12 / (EP01+CP1) 6.09 6.22 6.19 6.61 6.70 6.13 6.16 6.01 5.14 (R3×R4) / (d1m×d2s) 9.63 9.47 9.74 11.81 11.69 11.95 32.48 32.45 33.52 |f23| / d2m 4.56 4.51 4.60 10.82 10.85 11.05 10.58 10.48 10.65 |f34| / (D3s+D3m) 20.62 23.04 17.64 4.09 4.10 3.32 4.32 4.51 3.80 |f4| / (d4s+D4s) 16.74 17.07 17.32 2.05 2.18 2.23 1.50 1.52 1.58 R9 / (EP34+CP4) 15.94 15.04 15.33 32.73 31.05 32.36 12.32 11.60 12.18 (R10+R11) / EP45 -9.44 -9.88 -9.88 -12.44 -11.81 -10.80 -6.10 -5.98 -6.01 (d5s+d5m) / T56 24.91 24.63 24.91 23.39 23.44 23.37 29.76 31.09 30.85 (d0s+D0s) / EPD 3.19 3.36 3.25 3.90 3.69 3.56 3.49 3.50 3.49 |f1+f2| / (EP12+EP23) 6.87 6.99 7.08 16.12 16.38 17.51 11.33 11.33 11.12 Dim / TD(D1m / TD) 0.79 0.85 0.93 0.86 0.81 0.92 0.75 0.71 0.90 Dim / TD(D3m / TD) 1.04 0.93 1.21 0.95 0.94 1.16 0.85 0.81 0.97 Dim / TD(D5m / TD) 1.51 1.53 1.51 1.65 1.65 1.62 1.76 1.72 1.70 f / djm(f / d2m) 2.32 2.29 2.34 2.14 2.15 2.19 2.19 2.17 2.20 f / djm(f / d3m) 1.83 1.87 1.98 / / / / / / f / djm(f / d4m) / / / 1.20 1.22 1.26 1.30 1.26 1.33

[0134] Table 10

[0135] 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.

[0136] 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, include: An imaging lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side. The first lens has positive optical power, with a convex object side and a concave image side. The second lens has negative optical power, with a convex object side and a concave image side. The third and fourth lenses have different signs of optical power; the third lens has a convex object side and a concave image side. The fifth lens has positive optical power, with both its object and image sides being convex. The sixth lens has negative optical power, with at least one inflection point on either its object or image side, and both its object and image sides being concave. The Abbe numbers of the second and fourth lenses are both less than 25. Multiple spacer elements, including a third spacer element placed between the third lens and the fourth lens and in contact with the image-side surface of the third lens, and a fourth spacer element placed between the fourth lens and the fifth lens and in contact with the image-side surface of the fourth lens; as well as A lens barrel for housing the imaging lens group and the plurality of spacer elements; The optical imaging system has six lenses with optical power. The radius of curvature R9 of the object side of the fifth lens, the spacing EP34 of the image side of the third spacer and the object side of the fourth spacer along the optical axis, and the maximum thickness CP4 of the fourth spacer along the optical axis satisfy: 11.60≤R9 / (EP34+CP4)≤32.

73.

2. The optical imaging system according to claim 1, characterized in that, The plurality of spacers further includes a first spacer element placed between the first lens and the second lens and in contact with the image-side surface of the first lens, a second spacer element placed between the second lens and the third lens and in contact with the image-side surface of the second lens, and a fifth spacer element placed between the fifth lens and the sixth lens and in contact with the image-side surface of the fifth lens, wherein Dim is the outer diameter of the image-side surface of the spacer element of the image-side surface of the lens with an Abbe number greater than 50 in the imaging lens group, and TD is the distance from the object-side surface of the first lens to the image-side surface of the sixth lens on the optical axis. Where i is 1, D1m represents the outer diameter of the image side of the first spacer element, and D1m and TD satisfy: 0.71≤D1m / TD≤0.93; When i is 3, D3m represents the outer diameter of the image-side surface of the third spacer element, and D3m and TD satisfy: 0.81 ≤ D3m / TD ≤ 1.21; and When i is 5, D5m represents the outer diameter of the image side of the fifth spacer element, and D5m and TD satisfy: 1.51≤D5m / TD≤1.

76.

3. The optical imaging system according to claim 1, characterized in that, The plurality of spacers further includes a first spacer element placed between the first lens and the second lens and in contact with the image-side surface of the first lens, a second spacer element placed between the second lens and the third lens and in contact with the image-side surface of the second lens, and a fifth spacer element placed between the fifth lens and the sixth lens and in contact with the image-side surface of the fifth lens, wherein f is the effective focal length of the optical imaging system, and djm is the inner diameter of the image-side surface of the spacer element of the image-side surface of the lens with negative optical power in the imaging lens group; in, When j is 2, d2m represents the inner diameter of the image side of the second spacer element, and f and d2m satisfy: 2.14≤f / d2m≤2.34; When j is 3, d3m represents the inner diameter of the image side of the third spacer element, and f and d3m satisfy: 1.83≤f / d3m≤1.98; When j is 4, d4m represents the inner diameter of the image side of the fourth spacer element, and f and d4m satisfy: 1.20≤f / d4m≤1.

33.

4. The optical imaging system according to claim 1, characterized in that, The plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens; wherein, The combined focal length f12 of the first lens and the second lens, the spacing EP01 of 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 direction and the maximum thickness CP1 of the first spacer element along the optical axis direction satisfy: 5.14≤f12 / (EP01+CP1)≤6.

70.

5. The optical imaging system according to claim 1, characterized in that, The plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens, and a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens; wherein, 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 inner diameter d1m of the image side of the first spacer element and the inner diameter d2s of the object side of the second spacer element satisfy: 9.47≤(R3×R4) / (d1m×d2s)≤33.

52.

6. The optical imaging system according to claim 1, characterized in that, At least two of the first to the third lenses are meniscus lenses in the paraxial region.

7. The optical imaging system according to claim 1, characterized in that, The radius of curvature R2 of the image side surface of the first lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: R2>R12>0.

8. The optical imaging system according to any one of claims 1 to 7, characterized in that, The plurality of spacer elements further includes a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens, wherein, The combined focal length f23 of the second lens and the third lens and the inner diameter d2m of the image side of the second spacer element satisfy: 4.51≤|f23| / d2m≤11.

05.

9. The optical imaging system according to any one of claims 1 to 7, characterized in that, The combined focal length f34 of the third lens and the fourth lens, the outer diameter D3s of the object side of the third spacer element, and the outer diameter D3m of the image side of the third spacer element satisfy: 3.32≤|f34| / (D3s+D3m)≤23.

04.

10. The optical imaging system according to any one of claims 1 to 7, characterized in that, The effective focal length f4 of the fourth lens, the inner diameter d4s of the object side of the fourth spacer element, and the outer diameter D4s of the object side of the fourth spacer element satisfy: 1.50≤|f4| / (d4s+D4s)≤17.

32.

11. The optical imaging system according to any one of claims 2 to 7, characterized in that, The plurality of spacer elements further includes a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image-side surface of the fifth lens, wherein, The effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, the maximum thickness CP3 of the third spacer element along the optical axis and the maximum thickness CP5 of the fifth spacer element along the optical axis satisfy: 0.98≤(f5+f6) / (CP3+CP5)≤10.

72.

12. The optical imaging system according to any one of claims 1 to 7, characterized in that, The plurality of spacer elements further includes a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image-side surface of the fifth lens, wherein, The radius of curvature R10 of the image side of the fifth lens, the radius of curvature R11 of the object side of the sixth lens, and the spacing EP45 of the image side of the fourth spacer element and the object side of the fifth spacer element along the optical axis satisfy: -12.44≤(R10+R11) / EP45≤-5.

98.

13. The optical imaging system according to any one of claims 1 to 7, characterized in that, The plurality of spacer elements further includes a fifth spacer element disposed between the fifth lens and the sixth lens and in contact with the image-side surface of the fifth lens, wherein, The inner diameter d5s of the object side of the fifth spacer element, the inner diameter d5m of the image side of the fifth spacer element, and the air gap T56 between the fifth lens and the sixth lens on the optical axis satisfy: 23.37≤(d5s+d5m) / T56≤31.

09.

14. The optical imaging system according to any one of claims 1 to 7, characterized in that, The inner diameter d0s of the front end face of the lens barrel near the object side, the outer diameter D0s of the front end face of the lens barrel near the object side, and the entrance pupil diameter EPD of the optical imaging system satisfy the following condition: 3.19≤(d0s+D0s) / EPD≤3.

90.

15. The optical imaging system according to any one of claims 1 to 7, characterized in that, The plurality of spacer elements further includes a first spacer element disposed between the first lens and the second lens and in contact with the image-side surface of the first lens, and a second spacer element disposed between the second lens and the third lens and in contact with the image-side surface of the second lens; wherein, The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the spacing EP12 between the image side of the first spacer element and the object side of the second spacer element along the optical axis, and the spacing EP23 between the image side of the second spacer element and the object side of the third spacer element along the optical axis satisfy: 6.87≤|f1+f2| / (EP12+EP23)≤17.51.

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