Optical image capturing system

Abstract

The invention provides an optical imaging system. The optical imaging system comprises a lens barrel, a lens group and a plurality of spacing elements, and the lens group and the spacing elements are arranged in the lens barrel. The lens group comprises a first lens with positive focal power, a second lens with focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power and a sixth lens with negative focal power which are sequentially arranged along the optical axis direction of the optical imaging system from the object side to the image side; the optical imaging system satisfies the following conditions: 1.90 < = TD / f * tan (Semi-FOV) lt; 2.10, 2.10; 0.85 lt, 0.85 lt; (d0m-d0s) / f is less than or equal to 1.05. The six-piece wide-angle optical imaging system solves the problem that in a six-piece wide-angle optical imaging system in the prior art, marginal light is prone to being deflected to the inner wall face of the lens barrel to form stray light.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical imaging devices, in particular to an optical imaging system. BACKGROUND

[0002] With the continuous progress of the field of optical imaging technology, more and more electronic devices have imaging functions such as photographing and video recording, and users have higher and higher requirements for the imaging quality of optical imaging systems applied to such electronic devices. In order to meet the high imaging quality of optical imaging systems, the design of optical imaging systems faces many challenges.

[0003] For a six-piece optical imaging system, in some wide-angle optical imaging systems, the interval distance of the object side of the first lens and the image side of the sixth lens in the optical axis direction is relatively large with respect to the effective focal length of the optical imaging system, the effective focal length of the optical imaging system is relatively small, the deflection ability of the lens group to light is relatively large, and more light can be collected into the optical imaging system, the effective focal length of the optical imaging system is relatively small, so that the effective focal length of a single lens is more sensitive to the effective focal length of the entire optical imaging system, and when the effective focal length of a single lens changes, the edge light is easily deflected to the inner wall surface of the lens barrel, and the stray light is formed by the reflection of the inner wall surface of the lens barrel, which affects the imaging quality.

[0004] That is, the six-piece wide-angle optical imaging system in the prior art has the problem that the edge light is easily deflected to the inner wall surface of the lens barrel to form stray light. SUMMARY

[0005] The main purpose of the present application is to provide an optical imaging system to solve the problem that the six-piece wide-angle optical imaging system in the prior art has the problem that the edge light is easily deflected to the inner wall surface of the lens barrel to form stray light.

[0006] In order to achieve the above object, according to one aspect of the present application, there is provided an optical imaging system, comprising a lens barrel, and a lens group and a plurality of spacer elements arranged in the lens barrel, the lens group consisting of six lenses, the lens group comprising, in order from an object side to an image side along an optical axis direction of the optical imaging system, a first lens having a positive refractive power, a second lens having a refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, a fifth lens having a positive refractive power, and a sixth lens having a negative refractive power, an image side surface of the first lens being a convex surface, an image side surface of the fourth lens being a concave surface, an object side surface of the fifth lens being a concave surface, an image side surface of the fifth lens being a convex surface, and an air gap being provided between any two adjacent lenses in the lens group; the plurality of spacer elements comprising at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element, the first spacer element being arranged between the first lens and the second lens and being in contact with the image side surface of the first lens, the second spacer element being arranged between the second lens and the third lens and being in contact with the image side surface of the second lens, the third spacer element being arranged between the third lens and the fourth lens and being in contact with the image side surface of the third lens, the fourth spacer element being arranged between the fourth lens and the fifth lens and being in contact with the image side surface of the fourth lens, and the fifth spacer element being arranged between the fifth lens and the sixth lens and being in contact with the image side surface of the fifth lens; a distance TD in the optical axis direction between an object side surface of the first lens and an image side surface of the sixth lens, an effective focal length f of the optical imaging system, and a half of a maximum field of view angle Semi-FOV of the optical imaging system satisfy: 1.90≤TD / f×tan(Semi-FOV)<2.10; and an inner diameter d0m of an image side end surface of the lens barrel, an inner diameter d0s of an object side end surface of the lens barrel, and the effective focal length f of the optical imaging system satisfy: 0.85<(d0m-d0s) / f≤1.05.

[0007] According to another aspect of the present application, there is provided an optical imaging system, comprising a lens barrel, and a plurality of spacer elements and a lens group arranged in the lens barrel, the lens group consisting of six lenses, the lens group comprising, in order from an object side to an image side along an optical axis direction of the optical imaging system, a first lens having a positive refractive power, a second lens having a refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, a fifth lens having a positive refractive power, and a sixth lens having a negative refractive power, the image side surface of the first lens being convex, the image side surface of the fourth lens being concave, the object side surface of the fifth lens being concave, the image side surface of the fifth lens being convex, and an air gap being provided between any two adjacent lenses in the lens group; the plurality of spacer elements comprising at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element, the first spacer element being located between the first lens and the second lens and being in contact with the image side surface of the first lens, the second spacer element being located between the second lens and the third lens and being in contact with the image side surface of the second lens, the third spacer element being located between the third lens and the fourth lens and being in contact with the image side surface of the third lens, the fourth spacer element being located between the fourth lens and the fifth lens and being in contact with the image side surface of the fourth lens, and the fifth spacer element being located between the fifth lens and the sixth lens and being in contact with the image side surface of the fifth lens; a distance TD between the object side surface of the first lens and the image side surface of the sixth lens along the optical axis direction, an effective focal length f of the optical imaging system, and a half of a maximum field of view angle Semi-FOV of the optical imaging system satisfy: 1.90≤TD / f x tan(Semi-FOV)<2.10; an outer diameter D4m of the image side surface of the fourth spacer element, an inner diameter d4s of the object side surface of the fourth spacer element, an effective focal length f5 of the fifth lens, and an effective focal length f4 of the fourth lens satisfy: 0.10<(D4m-d4s) / (f5-f4)≤0.50.

[0008] According to another aspect of the present invention, an optical imaging system is provided, including a lens barrel and a lens group and a plurality of spacer elements disposed within the lens barrel. The lens group consists of six lenses, including a first lens with positive optical power, a second lens with optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, arranged sequentially from the object side to the image side along the optical axis of the optical imaging system. The image-side surface of the first lens is convex, the image-side surface of the fourth lens is concave, the object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. An air gap exists between adjacent lenses in the lens group. The plurality of spacer elements include at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element. The first spacer element is located between the first lens and the second lens and adjacent to the image-side surface of the first lens. The second spacer element is located between the second and third lenses and in contact with the image-side surface of the second lens; the third spacer element is located between the third and fourth lenses and in contact with the image-side surface of the third lens; the fourth spacer element is located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens; and the fifth spacer element is located between the fifth and sixth lenses and in contact with the image-side surface of the fifth lens. The distance TD between the object-side surface of the first lens and the image-side surface of the sixth lens in the optical axis direction, the effective focal length f of the optical imaging system, and half of the maximum field of view (Semi-FOV) of the optical imaging system satisfy the following: 1.90 ≤ TD / f × tan(Semi-FOV) < 2.10. The inner diameter d0s of the object-side end face of the lens barrel, the inner diameter d1s of the object-side surface of the first spacer element, and the maximum height L of the lens barrel satisfy the following: 0.50 < (d0s - d1s) / L < 0.82.

[0009] Furthermore, the maximum height L of the microscope tube and the outer diameter D0s of the object-side end face of the microscope tube satisfy the following relationship: 0.75 <L / D0s<0.90。

[0010] Furthermore, among the multiple spacer elements, the second spacer element has the smallest inner diameter, and the central thickness CT3 of the third lens on the optical axis of the optical imaging system, the central thickness CT2 of the second lens on the optical axis, and the inner diameter d2s of the object side of the second spacer element satisfy the following condition: 0.20 < (CT3 - CT2) / d2s < 0.35.

[0011] Furthermore, the outer diameter D1s of the object side of the first spacer element, the inner diameter d1s of the object side of the first spacer element, and the effective diameter DT12 of the object side of the first lens satisfy the following condition: 1.15 < (D1s - d1s) / DT12 < 1.65.

[0012] Furthermore, the following condition is satisfied among the inner diameter d3s of the object side surface of the third spacer element, the inner diameter d2m of the image side surface of the second spacer element, and the effective focal length f3 of the third lens: 0.05 ≤ (d3s - d2m) / f3 < 0.30.

[0013] Furthermore, the object side surface of the third lens is convex, the image side surface of the third lens is convex, and the following condition is satisfied among the curvature radius R5 of the object side surface of the third lens, the curvature radius R6 of the image side surface of the third lens, and the interval distance EP23 in the optical axis direction between the image side surface of the second spacer element and the object side surface of the third spacer element: 11.00 < (R5 + R6) / EP23 < 54.50.

[0014] Furthermore, the following condition is satisfied among the outer diameter D4m of the image side surface of the fourth spacer element, the inner diameter d4s of the object side surface of the fourth spacer element, the effective focal length f5 of the fifth lens, and the effective focal length f4 of the fourth lens: 0.10 < (D4m - d4s) / (f5 - f4) ≤ 0.50.

[0015] Furthermore, the following condition is satisfied among the outer diameter D5m of the image side surface of the fifth spacer element, the inner diameter d5m of the image side surface of the fifth spacer element, and the effective focal length f6 of the sixth lens: -1.80 < (D5m - d5m) / f6 < -0.25.

[0016] Furthermore, the center thickness of the fifth lens on the optical axis in the lens group is the largest, and the following condition is satisfied between the center thickness CT5 of the fifth lens on the optical axis and the interval distance EP45 in the optical axis direction between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element: 1.15 < CT5 / EP45 < 3.05.

[0017] Furthermore, when the following condition 1.55 < CT5 / EP45 < 3.05 is satisfied between the center thickness CT5 of the fifth lens on the optical axis and the interval distance EP45 in the optical axis direction between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element, the fifth auxiliary spacer element is located between the fifth lens and the sixth lens and contacts the image side surface of the fifth spacer element.

[0018] Furthermore, the following condition is satisfied among the maximum axial thickness CP5 of the fifth spacer element, the maximum axial thickness CP5b of the fifth auxiliary spacer element, the curvature radius R11 of the object side surface of the sixth lens, and the curvature radius R10 of the image side surface of the fifth lens: 0.10 < (CP5 + CP5b) / (R11 - R10) ≤ 0.20.

[0019] According to the technical solution of this invention, the optical imaging system includes a lens barrel and a lens group and multiple spacer elements disposed within the lens barrel. The lens group consists of six lenses, including a first lens with positive optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, arranged sequentially from the object side to the image side along the optical axis of the optical imaging system. The image-side surface of the first lens is convex, the image-side surface of the fourth lens is concave, the object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. There is an air gap between adjacent lenses in the lens group. The multiple spacer elements include at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element. The first spacer element is located between the first lens and the second lens and is in contact with the image-side surface of the first lens. The second spacer element is located between the second and third lenses and in contact with the image-side surface of the second lens; the third spacer element is located between the third and fourth lenses and in contact with the image-side surface of the third lens; the fourth spacer element is located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens; and the fifth spacer element is located between the fifth and sixth lenses and in contact with the image-side surface of the fifth lens. The distance TD between the object-side surface of the first lens and the image-side surface of the sixth lens in the optical axis direction, the effective focal length f of the optical imaging system, and half of the maximum field of view (Semi-FOV) of the optical imaging system satisfy the following: 1.90 ≤ TD / f × tan(Semi-FOV) < 2.10. The inner diameter d0m of the image-side end face of the lens barrel, the inner diameter d0s of the object-side end face of the lens barrel, and the effective focal length f of the optical imaging system satisfy the following: 0.85 < (d0m - d0s) / f ≤ 1.05.

[0020] The optical imaging system of this application consists of a lens barrel, six lenses, and at least five spacer elements, satisfying 1.90≤TD / f×tan(Semi-FOV)<2.10. Under the premise of wide-angle imaging, the distance between the object side of the first lens and the image side of the sixth lens in the optical axis direction is relatively large compared with the effective focal length of the optical imaging system. This makes the lens group have a greater ability to deflect light and can collect more light into the optical imaging system. The small effective focal length of the optical imaging system makes the contribution of the effective focal length of a single lens to the effective focal length of the entire optical imaging system more sensitive. When the effective focal length of a single lens changes, it is easy to deflect the edge light to the inner wall surface of the lens barrel, which is reflected by the inner wall surface of the lens barrel to form stray light and affect the image quality. Based on this, this application limits the entry of large-angle light rays into the optical imaging system by constraining (d0m-d0s) / f within a reasonable range and by constraining the inner diameter of the object-side end face of the lens barrel. This restricts the range of light rays entering the lens group, reducing the risk of stray light being formed by edge rays deflecting to the inner wall of the lens barrel. Simultaneously, by constraining the inner diameter of the image-side end face of the lens barrel, some light rays are limited from escaping the optical imaging system. This allows the lens barrel to effectively block light rays that deviate from their normal paths due to changes in the effective focal length of individual lenses, thereby reducing stray light falling onto the imaging surface. In other words, by constraining the relationship between the inner diameter of the object-side end face of the lens barrel, the inner diameter of the image-side end face of the lens barrel, and the effective focal length of the optical imaging system, stray light falling onto the imaging surface can be effectively reduced, improving image quality. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 A dimensioned diagram of an optical imaging system according to an alternative embodiment of the present invention is shown;

[0023] Figure 2 A partial structural schematic diagram of the optical imaging system of Embodiment 1-1 of the present invention is shown;

[0024] Figure 3 A partial structural schematic diagram of the optical imaging system of Embodiments 1-2 of the present invention is shown;

[0025] Figure 4 A partial structural schematic diagram of the optical imaging system of Embodiments 1-3 of the present invention is shown;

[0026] Figure 5 The on-axis chromatic aberration curve of the optical imaging system according to Embodiment 1 of the present invention is shown;

[0027] Figure 6The astigmatism curve of the optical imaging system according to Embodiment 1 of the present invention is shown;

[0028] Figure 7 The distortion curve of the optical imaging system according to Embodiment 1 of the present invention is shown;

[0029] Figure 8 A partial structural schematic diagram of the optical imaging system of Embodiment 2-1 of the present invention is shown;

[0030] Figure 9 A partial structural schematic diagram of the optical imaging system of Embodiment 2-2 of the present invention is shown;

[0031] Figure 10 A partial structural schematic diagram of the optical imaging system of Embodiments 2-3 of the present invention is shown;

[0032] Figure 11 The on-axis chromatic aberration curve of the optical imaging system according to Embodiment 2 of the present invention is shown;

[0033] Figure 12 The astigmatism curve of the optical imaging system according to Embodiment 2 of the present invention is shown;

[0034] Figure 13 The distortion curve of the optical imaging system according to Embodiment 2 of the present invention is shown;

[0035] Figure 14 A partial structural schematic diagram of the optical imaging system of Embodiment 3-1 of the present invention is shown;

[0036] Figure 15 A partial structural schematic diagram of the optical imaging system of Embodiment 3-2 of the present invention is shown;

[0037] Figure 16 A partial structural schematic diagram of the optical imaging system of Embodiments 3-3 of the present invention is shown;

[0038] Figure 17 The on-axis chromatic aberration curve of the optical imaging system of Embodiment 3 of the present invention is shown;

[0039] Figure 18 The astigmatism curve of the optical imaging system of Embodiment 3 of the present invention is shown;

[0040] Figure 19 The distortion curve of the optical imaging system of Embodiment 3 of the present invention is shown;

[0041] Figure 20 The diagram shows the principal ray path of an optical imaging system according to an optional embodiment of the present invention, which satisfies TD / f×tan(Semi-FOV)=1.94 and (d0m-d0s) / f=0.96.

[0042] Figure 21 The stray light spot diagram of an optical imaging system according to an optional embodiment of the present invention, satisfying TD / f×tan(Semi-FOV)=1.94 and (d0m-d0s) / f=0.96, is shown.

[0043] Figure 22 The principal ray path diagram of an example optical imaging system that satisfies TD / f×tan(Semi-FOV)=1.94 and (d0m-d0s) / f=0.70 is shown.

[0044] Figure 23 A stray light spot diagram of an example optical imaging system that satisfies TD / f×tan(Semi-FOV)=1.94 and (d0m-d0s) / f=0.70 is shown.

[0045] Figure 24 Another example of an optical imaging system with principal ray path diagrams satisfying TD / f×tan(Semi-FOV)=1.94 and (d0m-d0s) / f=1.30 is shown.

[0046] Figure 25 Another example of stray light spot pattern of an optical imaging system that satisfies TD / f×tan(Semi-FOV)=1.94 and (d0m-d0s) / f=1.30 is shown.

[0047] The above figures include the following reference numerals:

[0048] E1, First lens; P1, First spacer element; E2, Second lens; P2, Second spacer element; E3, Third lens; P3, Third spacer element; P3b, Third auxiliary spacer element; E4, Fourth lens; P4, Fourth spacer element; P4b, Fourth auxiliary spacer element; E5, Fifth lens; P5, Fifth spacer element; P5b, Fifth auxiliary spacer element; E6, Sixth lens; S1, Object-side surface of the first lens; S2, Image-side surface of the first lens; S3, Object-side surface of the second lens; S4, Image-side surface of the second lens; S5, Object-side surface of the third lens; S6, Image-side surface of the third lens; S7, Object-side surface of the fourth lens; S8, Image-side surface of the fourth lens; S9, Object-side surface of the fifth lens; S10, Image-side surface of the fifth lens; S11, Object-side surface of the sixth lens; S12, Image-side surface of the sixth lens. Detailed Implementation

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0051] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0052] 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.

[0053] 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.

[0054] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The determination of the surface shape in the paraxial region can be based on the judgment method commonly known in the art, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens database of optical software) to determine convexity or concavity. For the object side, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the image side, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex. In this application, the left side is the object side, and the right side is the image side.

[0055] To address the problem in existing six-element wide-angle optical imaging systems where edge rays are easily deflected to the inner wall of the lens barrel, forming stray light, this invention provides an optical imaging system.

[0056] like Figures 1 to 21As shown, the optical imaging system includes a lens barrel and a lens group and multiple spacer elements disposed within the lens barrel. The lens group consists of six lenses, including a first lens with positive optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, arranged sequentially from the object side to the image side along the optical axis of the optical imaging system. The image-side surface of the first lens is convex, the image-side surface of the fourth lens is concave, the object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. There is an air gap between adjacent lenses in the lens group. The multiple spacer elements include at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element. The first spacer element is located between the first lens and the second lens and is in contact with the image-side surface of the first lens. The second spacer element is located between the first lens and the second lens and is in contact with the image-side surface of the first lens. The element is located between the second and third lenses and in contact with the image-side surface of the second lens; the third spacer element is located between the third and fourth lenses and in contact with the image-side surface of the third lens; the fourth spacer element is located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens; the fifth spacer element is located between the fifth and sixth lenses and in contact with the image-side surface of the fifth lens; the distance TD between the object-side surface of the first lens and the image-side surface of the sixth lens in the optical axis direction, the effective focal length f of the optical imaging system, and half of the maximum field of view (Semi-FOV) of the optical imaging system satisfy the following: 1.90≤TD / f×tan(Semi-FOV)<2.10; the inner diameter d0m of the image-side end face of the lens barrel, the inner diameter d0s of the object-side end face of the lens barrel, and the effective focal length f of the optical imaging system satisfy the following: 0.85<(d0m-d0s) / f≤1.05.

[0057] The optical imaging system of this application consists of a lens barrel, six lenses, and at least five spacer elements, satisfying 1.90≤TD / f×tan(Semi-FOV)<2.10. Under the premise of wide-angle imaging, the distance between the object side of the first lens and the image side of the sixth lens in the optical axis direction is relatively large compared to the effective focal length of the optical imaging system. This makes the lens group have a greater ability to deflect light, and can collect more light into the optical imaging system. The small effective focal length of the optical imaging system makes the contribution of the effective focal length of a single lens to the effective focal length of the entire optical imaging system more sensitive. When the effective focal length of a single lens changes, it is easy to deflect edge light to the inner wall surface of the lens barrel, which is reflected by the inner wall surface of the lens barrel to form stray light, affecting the image quality. Based on this, this application limits the entry of large-angle light rays into the optical imaging system by constraining (d0m-d0s) / f within a reasonable range and by constraining the inner diameter of the object-side end face of the lens barrel. This restricts the range of light rays entering the lens group, reducing the risk of stray light being formed by edge rays deflecting to the inner wall of the lens barrel. Simultaneously, by constraining the inner diameter of the image-side end face of the lens barrel, some light rays are limited from escaping the optical imaging system. This allows the lens barrel to effectively block light rays that deviate from their normal paths due to changes in the effective focal length of individual lenses, thereby reducing stray light falling onto the imaging surface. In other words, by constraining the relationship between the inner diameter of the object-side end face of the lens barrel, the inner diameter of the image-side end face of the lens barrel, and the effective focal length of the optical imaging system, stray light falling onto the imaging surface can be effectively reduced, improving image quality.

[0058] In addition, please refer to the following Figures 20 to 25 As shown, under the premise that the optical imaging system satisfies 1.90≤TD / f×tan(Semi-FOV)<2.10, for example, TD / f×tan(Semi-FOV)=1.94, Figures 20 to 21 The principal ray path diagram and stray light spot diagram of an optical imaging system according to an optional embodiment of the present invention are shown respectively. Specifically, in this embodiment, the optical imaging system satisfies (d0m-d0s) / f=0.96. This embodiment is referred to as Scheme 1. Figures 22 to 23 The principal ray path diagram and stray light spot diagram of an example optical imaging system are shown respectively. Specifically, in this example, the optical imaging system satisfies (d0m-d0s) / f=0.70. This example is referred to as Example 1. Figures 24 to 25The diagrams show the principal ray path diagram and stray light spot diagram of another example optical imaging system. Specifically, in this example, the optical imaging system satisfies (d0m-d0s) / f=1.30, hereinafter referred to as Example 2. The stray light spot diagram simulates the geometrical ray points (Geometrical Ray SPOTS) formed by geometrical rays on the imaging surface. It also shows the energy intensity distribution of the stray light. The X and Y axes represent the spatial position of the imaging surface, showing the peak position of the stray light's energy distribution on the imaging surface. The color intensity represents the strength of the stray light's energy, i.e., the luminous flux (in lumens per square millimeter) of stray light on the imaging surface.

[0059] like Figure 20 As shown, when the optical imaging system satisfies (d0m-d0s) / f=0.96, controlling d0m and d0s within an appropriate range results in a reasonable ratio between the difference in inner diameter between the image-side and object-side end faces of the lens barrel and the effective focal length of the optical imaging system. This limits the range of light rays entering and exiting the optical imaging system, resulting in weak stray light energy on the imaging surface, thus reducing the risk of stray light generation and minimizing its impact on image quality. Combined with... Figure 21 It can be seen that only a small amount of light is reflected from near the inner diameter of the image-side end face of the lens tube to form a small amount of scattered stray light, indicating that the optical imaging system in Scheme 1 has good imaging quality.

[0060] like Figure 22 As shown, when the optical imaging system satisfies (d0m-d0s) / f=0.70, the ratio of the difference between the inner diameters of the image-side end face and the object-side end face of the lens barrel to the effective focal length of the optical imaging system is too small. In this case, the inner diameter of the object-side end face of the lens barrel is too large, resulting in a large amount of light incident from the object-side end of the lens barrel. Especially large-angle light entering the optical imaging system leads to a large light range, and edge light rays are easily deflected into the non-effective diameter region of the lens, forming stray light, resulting in severe stray light on the imaging surface. Combined with... Figure 23 It can be seen that the edge rays are reflected by the inner diameter of the first lens and the first spacer element to form arc-shaped stray light, indicating that the imaging quality of the optical imaging system in Example 1 is poor.

[0061] like Figure 24 As shown, when the optical imaging system satisfies (d0m-d0s) / f=1.30, the ratio of the difference between the inner diameters of the image-side end face and the object-side end face of the lens barrel to the effective focal length of the optical imaging system is too large. In this case, the inner diameter of the image-side end face of the lens barrel is too large, resulting in a large amount of light emanating from the optical imaging system. In particular, stray light generated in the non-effective diameter region of the rear lens cannot be blocked by the image-side end face of the lens barrel, allowing stray light to reach the imaging plane, leading to severe stray light on the imaging plane. Combined with... Figure 25It can be seen that the light is reflected by the image-side end face of the sixth lens and the barrel, forming fan-shaped stray light with a relatively high energy intensity, indicating that the imaging quality of the optical imaging system in Example 2 is poor.

[0062] In summary, when the optical imaging system satisfies 1.90 ≤ TD / f × tan(Semi-FOV) < 2.10 and 0.85 < (d0m - d0s) / f ≤ 1.05, the ratio of the difference in the inner diameters of the image-side end face and the object-side end face of the barrel to the effective focal length of the optical imaging system is relatively reasonable. The light entering and exiting the optical imaging system is restricted within a reasonable range, and the stray light on the imaging surface is minimized, resulting in the best imaging quality of the optical imaging system. Therefore, in this application, by constraining TD / f × tan(Semi-FOV) and (d0m - d0s) / f within a reasonable range, by constraining the inner diameter of the object-side end face of the barrel to restrict some light from entering the optical imaging system, and at the same time constraining the inner diameter of the image-side end face of the barrel to restrict some light from exiting the optical imaging system, the barrel can effectively block the light deviating from the normal path caused by the change in the effective focal length of a single lens, thereby reducing the risk of generating stray light.

[0063] For example, in some optional embodiments, the first lens has a positive optical power and converges the light from the object side to facilitate controlling the range of light entering the optical imaging system. For another example, in some optional embodiments, the third lens has a positive optical power and can moderately converge the light, enabling the light to transition smoothly to the subsequent lenses, which is beneficial to improving the imaging quality of the optical imaging system. For another example, in some optional embodiments, the fourth lens has a negative optical power, which can balance the aberration of the front lens and reasonably diverge the light to maintain a stable light trend. For another example, in some optional embodiments, the fifth lens has a positive optical power and appropriately converges the light to maintain a stable light trend. For another example, in some optional embodiments, the sixth lens has a negative optical power, which can balance the aberration of the front lens and reasonably diverge the light to the imaging surface to ensure the imaging quality. For another example, in some optional embodiments, the image side surface of the first lens is convex. The image side surface of the fourth lens is concave. The object side surface of the fifth lens is concave, and the image side surface of the fifth lens is convex. By reasonably constraining the surface types of each lens, it is beneficial to reasonably constrain the light trend, ensure the smooth transition of the light, and is beneficial to correcting the aberration.

[0064] In some optional embodiments, the following relationship is satisfied between the maximum height L of the barrel and the outer diameter D0s of the object-side end face of the barrel: 0.75 < L / D0s < 0.90. By controlling L / D0s within a reasonable range, the ratio of the outer diameter of the object-side end face of the barrel to the maximum height of the barrel can be controlled, which can constrain the overall size of the optical imaging system and is beneficial to reducing the forming difficulty of the barrel while realizing the miniaturization of the optical imaging system.

[0065] It should be noted that the maximum height L of the microscope tube is the distance between the object-side end face and the image-side end face of the microscope tube in the optical axis direction.

[0066] In some optional embodiments, the inner diameter of the second spacer element is the smallest among the multiple spacer elements. The central thickness CT3 of the third lens on the optical axis of the optical imaging system, the central thickness CT2 of the second lens on the optical axis, and the inner diameter d2s of the object side of the second spacer element satisfy the following condition: 0.20 < (CT3 - CT2) / d2s < 0.35. By controlling (CT3 - CT2) / d2s within a reasonable range and ensuring that the inner diameter of the second spacer element is the smallest among the multiple spacer elements, and by constraining the central thicknesses of the third and second lenses and the inner diameter of the object side of the second spacer element between them, it is ensured that the second spacer element can effectively block non-imaging light rays between the second and third lenses, reduce stray light, and improve the imaging quality of the optical imaging system.

[0067] In some alternative embodiments, the outer diameter D1s of the object side of the first spacer element, the inner diameter d1s of the object side of the first spacer element, and the effective diameter DT12 of the object side of the first lens satisfy the following relationship: 1.15 < (D1s - d1s) / DT12 < 1.65. By controlling (D1s - d1s) / DT12 within a reasonable range, the outer diameter of the object side of the first spacer element and the width of the annular band can be constrained, enabling the first spacer element to block stray light rays from the edge of the effective optical diameter region of the first lens, thereby reducing the number and intensity of stray light spots on the imaging surface.

[0068] In some alternative embodiments, the inner diameter d3s of the object side of the third spacer, the inner diameter d2m of the image side of the second spacer, and the effective focal length f3 of the third lens satisfy the following: 0.05 ≤ (d3s - d2m) / f3 < 0.30. By controlling (d3s - d2m) / f3 within a reasonable range, the ratio of the difference between the inner diameter of the object side of the third spacer and the inner diameter of the image side of the second spacer to the effective focal length of the third lens can be configured. While maintaining the refractive power of the third lens, stray light rays from the third lens can be effectively blocked by the spacers on its object side and image side.

[0069] In some alternative embodiments, the object side surface of the third lens is convex, the image side surface of the third lens is convex, and the following relationship is satisfied among the radius of curvature R5 of the object side surface of the third lens, the radius of curvature R6 of the image side surface of the third lens, and the axial distance EP23 between the image side surface of the second spacer element and the object side surface of the third spacer element: 11.00 < (R5 + R6) / EP23 < 54.50. By controlling the surface shape of the third lens and keeping (R5 + R6) / EP23 within a reasonable range, it is beneficial to improve the rationality of the surface shape of the third lens, and at the same time control the edge thickness of the third lens within a reasonable range, thereby ensuring the processing feasibility and molding yield of the third lens.

[0070] In some alternative embodiments, the following relationship is satisfied among the outer diameter D4m of the image side surface of the fourth spacer element, the inner diameter d4s of the object side surface of the fourth spacer element, the effective focal length f5 of the fifth lens, and the effective focal length f4 of the fourth lens: 0.10 < (D4m - d4s) / (f5 - f4) ≤ 0.50. By controlling (D4m - d4s) / (f5 - f4) within a reasonable range, and by reasonably controlling the difference between the effective focal lengths of the fifth lens and the fourth lens and the difference between the outer diameter of the image side surface and the inner diameter of the object side surface of the fourth spacer element between the two lenses, it is possible to effectively ensure that the fourth spacer element blocks the internal reflection stray light generated by the fourth lens and reduce the refraction angle of the light entering the fifth lens, thereby improving the imaging quality of the optical imaging system.

[0071] In some alternative embodiments, the central thickness of the fifth lens in the lens group on the optical axis of the optical imaging system is the largest, and the following relationship is satisfied between the central thickness CT5 of the fifth lens on the optical axis and the axial distance EP45 between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element: 1.15 < CT5 / EP45 < 3.05. By controlling CT5 / EP45 within a reasonable range, the central thickness of the fifth lens and the edge thickness of the non-effective diameter region can be constrained within a reasonable range, improving the surface shape uniformity of the fifth lens, which is beneficial to the mold processing and injection molding of the fifth lens, and reducing the risk of assembly sensitivity (AS, Assembly Sensitivity) of the optical imaging system.

[0072] In some optional embodiments, when the central thickness CT5 of the fifth lens on the optical axis of the optical imaging system and the spacing distance EP45 between the image side of the fourth spacer element and the object side of the fifth spacer element in the optical axis direction satisfy 1.55 < CT5 / EP45 < 3.05, the plurality of spacer elements further includes a fifth auxiliary spacer element, which is located between the fifth lens and the sixth lens and contacts the image side of the fifth spacer element. When the central thickness of the fifth lens is relatively large with respect to the edge thickness of its non-effective diameter region, stray light is likely to occur between the fifth lens and the sixth lens. At this time, setting the fifth auxiliary spacer element can effectively block the primary reflected stray light from the fifth spacer element and part of the internal reflected stray light of the sixth lens, further reducing the stray light of the optical imaging system and improving the imaging quality.

[0073] In some optional embodiments, the outer diameter D5m of the image side of the fifth spacer element, the inner diameter d5m of the image side of the fifth spacer element, and the effective focal length f6 of the sixth lens satisfy: -1.80 < (D5m - d5m) / f6 < -0.25. By controlling (D5m - d5m) / f6 within a reasonable range, the annular width of the image side of the fifth spacer element can be controlled, effectively reducing the stray light rays entering the sixth lens.

[0074] In some optional embodiments, the maximum axial thickness CP5 of the fifth spacer element, the maximum axial thickness CP5b of the fifth auxiliary spacer element, the curvature radius R11 of the object side of the sixth lens, and the curvature radius R10 of the image side of the fifth lens satisfy: 0.10 < (CP5 + CP5b) / (R11 - R10) ≤ 0.20. By controlling (CP5 + CP5b) / (R11 - R10) within a reasonable range, by adjusting the difference between the maximum axial thicknesses of the fifth spacer element and the fifth auxiliary spacer element and the curvature radii of the object side of the sixth lens and the image side of the fifth lens, the thickness of the spacer element between the image side of the fifth lens and the object side of the sixth lens is reasonably controlled, and the gap between their non-effective diameter regions is filled by the spacer element, thereby ensuring the assembly stability between the fifth lens and the sixth lens.

[0075] In some optional embodiments, half of the maximum field angle Semi-FOV of the optical imaging system satisfies: 52.40° ≤ Semi-FOV < 53.8°.

[0076] In another alternative embodiment, an optical imaging system is provided, including a lens barrel and a lens group and multiple spacer elements disposed within the lens barrel. The lens group consists of six lenses, including a first lens with positive optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, arranged sequentially from the object side to the image side along the optical axis of the optical imaging system. The image-side surface of the first lens is convex, the image-side surface of the fourth lens is concave, the object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. An air gap exists between adjacent lenses in the lens group. The multiple spacer elements include at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element. The first spacer element is located between the first lens and the second lens and contacts the image-side surface of the first lens. The second spacer element... The first lens is located between the second and third lenses and in contact with the image-side surface of the second lens; the third spacer is located between the third and fourth lenses and in contact with the image-side surface of the third lens; the fourth spacer is located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens; the fifth spacer is located between the fifth and sixth lenses and in contact with the image-side surface of the fifth lens; the distance TD between the object-side surface of the first lens and the image-side surface of the sixth lens in the optical axis direction, the effective focal length f of the optical imaging system, and half of the maximum field of view (Semi-FOV) of the optical imaging system satisfy: 1.90≤TD / f×tan(Semi-FOV)<2.10; the outer diameter D4m of the image-side surface of the fourth spacer, the inner diameter d4s of the object-side surface of the fourth spacer, the effective focal length f5 of the fifth lens, and the effective focal length f4 of the fourth lens satisfy: 0.10<(D4m-d4s) / (f5-f4)≤0.50.

[0077] The optical imaging system of this application consists of a lens barrel, six lenses, and at least five spacer elements, satisfying 1.90≤TD / f×tan(Semi-FOV)<2.10. Under the premise of wide-angle imaging, the distance between the object side of the first lens and the image side of the sixth lens in the optical axis direction is relatively large compared with the effective focal length of the optical imaging system. This makes the lens group have a greater ability to deflect light and can collect more light into the optical imaging system. The small effective focal length of the optical imaging system makes the contribution of the effective focal length of a single lens to the effective focal length of the entire optical imaging system more sensitive. When the effective focal length of a single lens changes, it is easy to deflect the edge light to the inner wall surface of the lens barrel to form reflected stray light, which affects the image quality. Based on this, by constraining (D4m-d4s) / (f5-f4) within a reasonable range, and by reasonably controlling the difference in effective focal length between the fifth and fourth lenses and the difference in outer diameter of the image side and inner diameter of the object side of the fourth spacer between the two lenses, this application can effectively ensure that the fourth spacer blocks the internal stray light generated by the fourth lens and reduce the refraction angle of light entering the fifth lens, thereby improving the imaging quality of the optical imaging system.

[0078] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0079] In another alternative embodiment, an optical imaging system is provided, including a lens barrel and a lens group and multiple spacer elements disposed within the lens barrel. The lens group consists of six lenses, including a first lens with positive optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, arranged sequentially from the object side to the image side along the optical axis of the optical imaging system. The image-side surface of the first lens is convex, the image-side surface of the fourth lens is concave, the object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. An air gap exists between adjacent lenses in the lens group. The multiple spacer elements include at least a first spacer element, a second spacer element, a third spacer element, a fourth spacer element, and a fifth spacer element. The first spacer element is located between the first lens and the second lens and is adjacent to the first lens. The image side of the first lens is in contact with the image side of the second lens, the second spacer element is located between the second and third lenses and in contact with the image side of the second lens, the third spacer element is located between the third and fourth lenses and in contact with the image side of the third lens, the fourth spacer element is located between the fourth and fifth lenses and in contact with the image side of the fourth lens, and the fifth spacer element is located between the fifth and sixth lenses and in contact with the image side of the fifth lens; the distance TD between the object side of the first lens and the image side of the sixth lens in the optical axis direction, the effective focal length f of the optical imaging system, and half of the maximum field of view (Semi-FOV) of the optical imaging system satisfy: 1.90≤TD / f×tan(Semi-FOV)<2.10; the inner diameter d0s of the object side end face of the lens barrel, the inner diameter d1s of the object side face of the first spacer element, and the maximum height L of the lens barrel satisfy: 0.50<(d0s-d1s) / L<0.82.

[0080] The optical imaging system of this application consists of a lens barrel, six lenses, and at least five spacer elements, satisfying 1.90≤TD / f×tan(Semi-FOV)<2.10. Under the premise of wide-angle imaging, the distance between the object side of the first lens and the image side of the sixth lens in the optical axis direction is relatively large compared with the effective focal length of the optical imaging system. This makes the lens group have a greater ability to deflect light and can collect more light into the optical imaging system. The small effective focal length of the optical imaging system makes the contribution of the effective focal length of a single lens to the effective focal length of the entire optical imaging system more sensitive. When the effective focal length of a single lens changes, it is easy to deflect the edge light to the inner wall surface of the lens barrel to form reflected stray light, which affects the image quality. Based on this, by constraining (d0s-d1s) / L within a reasonable range, this application, while constraining the overall axial dimensions of the optical imaging system, not only restricts the entry of some large-angle light rays on the object-side end face of the lens barrel and constrains the range of light rays entering the lens group, reducing the risk of stray light being formed by edge light rays deflected to the inner wall surface of the lens barrel, but also allows the first spacer element to block stray light generated by the edge portion of the optical effective diameter region of the image side of the first lens, which helps to improve the problem of internal reflection stray light of the first lens, thereby reducing the overall internal stray light of the optical imaging system and improving the imaging quality of the optical imaging system.

[0081] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0082] Optionally, the optical imaging system described above may also include a filter located between the imaging plane and the sixth lens.

[0083] Optionally, the optical imaging system described above may also include protective glass for protecting the photosensitive element located on the imaging surface.

[0084] It should be noted that each lens consists of an effective optical diameter region at the center and an optical structure region at the edge. The optical structure region is located on the outer periphery of the effective optical diameter region and is arranged circumferentially around it. The effective optical diameter region is used for the passage of imaging light rays, while the optical structure region is not used for the passage of imaging light rays. The optical structure region is used to contact the lens barrel, adjacent lenses, or adjacent spacer elements. The optical structure region is also called the non-effective optical diameter region.

[0085] In this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike a spherical lens, which has a constant curvature from its center to its periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism (also known as astigmatism). By using aspherical lenses, aberrations occurring during image formation can be eliminated as much as possible, thereby improving image quality.

[0086] Figure 1 A schematic diagram showing the dimensions of an optical imaging system according to this application is provided. Figure 1 The figures clearly indicate parameters such as d1s, D1s, d2s, d2m, d3s, d4s, D4m, d5s, D5m, d0s, d0m, D0s, EP23, EP45, CP5, L, CP5b, and DT12 to provide a clear and intuitive understanding of their meaning. To facilitate the description of the optical imaging system and the specific lens profiles, these parameters will not be shown in the accompanying figures when describing specific embodiments.

[0087] It should be noted that the object-side end face of the lens tube refers to the surface of the lens tube closest to the object side and perpendicular to the optical axis, the image-side end face of the lens tube refers to the surface of the lens tube closest to the image side and perpendicular to the optical axis, the object-side side of the spacer element refers to the surface of the spacer element closest to the object side and perpendicular to the optical axis, and the image-side side of the spacer element refers to the surface of the spacer element closest to the image side and perpendicular to the optical axis.

[0088] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters applicable to the optical imaging systems described above.

[0089] It should be noted that in the following Embodiment 1, there are Embodiments 1-1, 1-2, and 1-3; in Embodiment 2, there are Embodiments 2-1, 2-2, and 2-3; and in Embodiment 3, there are Embodiments 3-1, 3-2, and 3-3. In the three embodiments within the same embodiment, the parameters such as the radius of curvature, center thickness, and inter-lens spacing and higher-order coefficients of the optical imaging system from the first to the sixth lens are the same. However, the parameters such as the thickness, inner diameter, and outer diameter of the lens barrel, the first to fifth spacer elements, and the shape of some lenses are different. In other words, the main structure used for imaging is the same, but the auxiliary structures used for imaging are different.

[0090] It should be noted that any of the embodiments described in Examples 1 to 3 below are applicable to all implementation methods of this application.

[0091] Example 1

[0092] like Figures 2 to 7 As shown, the optical imaging system of Embodiment 1 is described. Figure 2 A schematic diagram of the optical imaging system of Embodiment 1-1 is shown. Figure 3 A schematic diagram of the optical imaging system of Embodiments 1-2 is shown. Figure 4 A schematic diagram of the optical imaging system of Examples 1-3 is shown.

[0093] like Figures 2 to 4As shown, the optical imaging system includes a lens barrel, six lenses, and multiple spacer elements. The lens barrel includes, in order from the object side to the image side, a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3, a fourth lens E4, a fourth spacer element P4, a fifth lens E5, a fifth spacer element P5, a fifth auxiliary spacer element P5b, and a sixth lens E6.

[0094] like Figure 2 The diagram shows a schematic of the optical imaging system of Embodiment 1-1. In this embodiment, the object-side surface S1 of the first lens is in contact with the lens barrel; the object-side surface and image-side surface of the first spacer element P1 are in contact with the image-side surface S2 of the first lens and the object-side surface S3 of the second lens, respectively; the object-side surface and image-side surface of the second spacer element P2 are in contact with the image-side surface S4 of the second lens and the object-side surface S5 of the third lens, respectively; the object-side surface and image-side surface of the third spacer element P3 are in contact with the image-side surface S6 of the third lens and the object-side surface S7 of the fourth lens, respectively; the object-side surface and image-side surface of the fourth spacer element P4 are in contact with the image-side surface S8 of the fourth lens and the object-side surface S9 of the fifth lens, respectively; the object-side surface and image-side surface of the fifth spacer element P5 are in contact with the image-side surface S10 of the fifth lens and the object-side surface of the fifth auxiliary spacer element P5b, respectively; the image-side surface of the fifth auxiliary spacer element P5b is in contact with the object-side surface S11 of the sixth lens; and the image-side surface S12 of the sixth lens is spaced apart from the lens barrel.

[0095] like Figure 3 The diagram shown is a schematic representation of the optical imaging system of Embodiment 1-2. The difference from Embodiment 1-1 is that a third auxiliary spacer element P3b is also provided on the image side of the third lens. In this case, the image side of the third spacer element P3b contacts the object side of the third auxiliary spacer element P3b, and the image side of the third auxiliary spacer element P3b contacts the object side S7 of the fourth lens. The bearing method of the other spacers is the same as in Embodiment 1-1, and can be referred to the relevant description in Embodiment 1-1, which will not be repeated here.

[0096] like Figure 4 The diagram shown is a schematic representation of the optical imaging system of Embodiments 1-3. The support method of each spacer element is the same as that of Embodiment 1-1, and can be referred to the relevant description in Embodiment 1-1, which will not be repeated here.

[0097] In summary, the structural parameters of the optical imaging system of Embodiment 1 under Embodiments 1-1, 1-2, and 1-3 are shown in Table 8.

[0098] In Embodiment 1, the first lens E1 has positive optical power, its object-side surface S1 is concave, and its image-side surface S2 is convex. The second lens E2 has negative optical power, its object-side surface S3 is convex, and its image-side surface S4 is concave. The third lens E3 has positive optical power, its object-side surface S5 is convex, and its image-side surface S6 is convex. The fourth lens E4 has negative optical power, its object-side surface S7 is convex, and its image-side surface S8 is concave. The fifth lens E5 has positive optical power, its object-side surface S9 is concave, and its image-side surface S10 is convex. The sixth lens E6 has negative optical power, its object-side surface S11 is convex, and its image-side surface S12 is concave. In Table 1, OBJ (not shown in the figure) is the object plane of the optical imaging system; S13 and S14 (not shown in the figure) can be the object-side and image-side surfaces of the filter or protective glass; S15 (not shown in the figure) is the imaging plane of the optical imaging system; and STO (not shown in the figure) is the aperture stop, located between the second lens E2 and the third lens E3. Light rays from the object plane pass through S1 to S14 to reach S15 (the imaging plane).

[0099] Table 1 shows the basic structural parameters of the optical imaging system in Embodiment 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0100] Table 1

[0101]

[0102] In Embodiment 1, the object-side surface and image-side surface of the first lens E1 to the sixth lens E6 are both aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0103] Formula (1)

[0104] 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 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 that can be used for each aspherical mirror S1-S12 in Example 1.

[0105] Table 2

[0106]

[0107] Figure 5The 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 optical imaging system. Figure 6 The astigmatism curves of the optical imaging system of Embodiment 1 are shown, which represent the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 7 The distortion curves of the optical imaging system of Embodiment 1 are shown, which represent the distortion magnitude values ​​corresponding to different field of view angles.

[0108] according to Figures 5 to 7 As can be seen, the optical imaging system given in Example 1 can achieve good imaging quality.

[0109] Example 2

[0110] like Figures 8 to 13 As shown, the optical imaging system of Embodiment 2 is described. Figure 8 A schematic diagram of the optical imaging system of Embodiment 2-1 is shown. Figure 9 A schematic diagram of the optical imaging system of Embodiment 2-2 is shown. Figure 10 A schematic diagram of the optical imaging system of Embodiments 2-3 is shown.

[0111] like Figures 8 to 10 As shown, the optical imaging system includes a lens barrel, six lenses, and multiple spacer elements. The lens barrel includes a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3, a fourth lens E4, a fourth spacer element P4, a fifth lens E5, a fifth spacer element P5, and a sixth lens E6 arranged sequentially from the object side to the image side.

[0112] like Figure 8 The diagram shows a schematic of the optical imaging system of Embodiment 2-1. In this embodiment, the optical imaging system further includes a fifth auxiliary spacer element P5b located on the image side of the fifth spacer element P5. The object side surface S1 of the first lens is in contact with the lens barrel; the object side surface and image side surface of the first spacer element P1 are in contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively; the object side surface and image side surface of the second spacer element P2 are in contact with the image side surface S4 of the second lens and the object side surface S5 of the third lens, respectively; the object side surface and image side surface of the third spacer element P3 are in contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, respectively; the object side surface and image side surface of the fourth spacer element P4 are in contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively; the object side surface and image side surface of the fifth spacer element P5 are in contact with the image side surface S10 of the fifth lens and the object side surface of the fifth auxiliary spacer element P5b, respectively; the image side surface of the fifth auxiliary spacer element P5b is in contact with the object side surface S11 of the sixth lens; and the image side surface S12 of the sixth lens is spaced apart from the lens barrel.

[0113] like Figure 9 The diagram shown is a schematic representation of the optical imaging system of Embodiment 2-2. In this embodiment, the optical imaging system further includes a fifth auxiliary spacer element P5b located on the image side of the fifth spacer element P5. The bearing method of each spacer element is the same as that in Embodiment 2-1, and can be referred to the relevant description in Embodiment 2-1, which will not be repeated here.

[0114] like Figure 10 The diagram shown is a schematic representation of the optical imaging system of Embodiment 2-3. The difference from Embodiment 2-1 is that only the fifth spacer element P5 is provided on the image side of the fifth lens. In this case, the object side and image side of the fifth spacer element P5 are in contact with the image side side S10 of the fifth lens and the object side side S11 of the sixth lens, respectively. The bearing method of the other spacer elements is the same as in Embodiment 2-1, and can be referred to the relevant description in Embodiment 2-1, which will not be repeated here.

[0115] In summary, the structural parameters of the optical imaging system of Embodiment 2 under Embodiments 2-1, 2-2, and 2-3 are shown in Table 8.

[0116] In Embodiment 2, the first lens E1 has positive optical power, its object-side surface S1 is convex, and its image-side surface S2 is convex. The second lens E2 has positive optical power, its object-side surface S3 is convex, and its image-side surface S4 is concave. The third lens E3 has positive optical power, its object-side surface S5 is convex, and its image-side surface S6 is convex. The fourth lens E4 has negative optical power, its object-side surface S7 is concave, and its image-side surface S8 is concave. The fifth lens E5 has positive optical power, its object-side surface S9 is concave, and its image-side surface S10 is convex. The sixth lens E6 has negative optical power, its object-side surface S11 is convex, and its image-side surface S12 is concave. In Table 3, OBJ (not shown in the figure) is the object plane of the optical imaging system; S13 and S14 (not shown in the figure) can be the object-side and image-side surfaces of the filter or protective glass; S15 (not shown in the figure) is the imaging plane of the optical imaging system; and STO (not shown in the figure) is the aperture stop, located between the second lens E2 and the third lens E3. Light rays from the object plane pass through S1 to S14 to reach S15 (the imaging plane).

[0117] Table 3 shows the basic structural parameters of the optical imaging system in Embodiment 2, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0118] Table 3

[0119]

[0120] Table 4 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for each aspherical mirror S1-S12 in Example 2. The surface shape of each aspherical surface can be defined by formula (1) given in Example 1 above.

[0121] Table 4

[0122]

[0123] Figure 11 The on-axis chromatic aberration curve of the optical imaging system of Embodiment 2 is shown, which represents the deflection of the focal point after light of different wavelengths passes through the optical imaging system. Figure 12 The astigmatism curves of the optical imaging system of Embodiment 2 are shown, which represent the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 13 The distortion curves of the optical imaging system of Embodiment 2 are shown, which represent the distortion magnitude values ​​corresponding to different field of view angles.

[0124] according to Figures 11 to 13 It can be seen that the optical imaging system given in Example 2 can achieve good imaging quality.

[0125] Example 3

[0126] like Figures 14 to 19 As shown, the optical imaging system of Embodiment 3 is described. Figure 14 A schematic diagram of the optical imaging system of Embodiment 3-1 is shown. Figure 15 A schematic diagram of the optical imaging system of Embodiment 3-2 is shown. Figure 16 A schematic diagram of the optical imaging system of Embodiment 3-3 is shown.

[0127] like Figures 14 to 16 As shown, the optical imaging system includes a lens barrel, six lenses, and multiple spacer elements. The lens barrel includes a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, a third lens E3, a third spacer element P3, a fourth lens E4, a fourth spacer element P4, a fifth lens E5, a fifth spacer element P5, and a sixth lens E6 arranged sequentially from the object side to the image side.

[0128] like Figure 14The diagram shows a schematic of the optical imaging system of Embodiment 3-1. In this embodiment, the object-side surface S1 of the first lens is in contact with the lens barrel; the object-side surface and image-side surface of the first spacer element P1 are in contact with the image-side surface S2 of the first lens and the object-side surface S3 of the second lens, respectively; the object-side surface and image-side surface of the second spacer element P2 are in contact with the image-side surface S4 of the second lens and the object-side surface S5 of the third lens, respectively; the object-side surface and image-side surface of the third spacer element P3 are in contact with the image-side surface S6 of the third lens and the object-side surface S7 of the fourth lens, respectively; the object-side surface and image-side surface of the fourth spacer element P4 are in contact with the image-side surface S8 of the fourth lens and the object-side surface S9 of the fifth lens, respectively; the object-side surface and image-side surface of the fifth spacer element P5 are in contact with the image-side surface S10 of the fifth lens and the object-side surface S11 of the sixth lens, respectively; and the image-side surface S12 of the sixth lens is spaced apart from the lens barrel.

[0129] like Figure 15 The diagram shown is a schematic representation of the optical imaging system of Embodiment 3-2. The difference from Embodiment 3-1 is that a fifth auxiliary spacer element P5b is also provided on the image side of the fifth lens. In this case, the image side of the fifth spacer element P5b contacts the object side of the fifth auxiliary spacer element P5b, and the image side of the fifth auxiliary spacer element P5b contacts the object side S11 of the sixth lens. The bearing method of the other spacers is the same as in Embodiment 3-1, and can be referred to the relevant description in Embodiment 3-1, which will not be repeated here.

[0130] like Figure 16 The diagram shown is a schematic representation of the optical imaging system of Embodiment 3-3. The difference from Embodiment 3-1 is that a fourth auxiliary spacer element P4b is also provided on the image side of the fourth spacer element P4, and a fifth auxiliary spacer element P5b is also provided on the image side of the fifth spacer element P5. In this case, the image side of the fourth spacer element P4 contacts the object side of the fourth auxiliary spacer element P4b, and the image side of the fourth auxiliary spacer element P4b contacts the object side S9 of the fifth lens; the image side of the fifth spacer element P5 contacts the object side of the fifth auxiliary spacer element P5b, and the image side of the fifth auxiliary spacer element P5b contacts the object side S11 of the sixth lens. The bearing method of the other spacer elements is the same as in Embodiment 3-1, and can be referred to the relevant description in Embodiment 3-1, which will not be repeated here.

[0131] In summary, the structural parameters of the optical imaging system of Embodiment 3 under Embodiments 3-1, 3-2, and 3-3 are shown in Table 8.

[0132] In Embodiment 3, the first lens E1 has positive optical power, its object-side surface S1 is concave, and its image-side surface S2 is convex. The second lens E2 has negative optical power, its object-side surface S3 is convex, and its image-side surface S4 is concave. The third lens E3 has positive optical power, its object-side surface S5 is convex, and its image-side surface S6 is convex. The fourth lens E4 has negative optical power, its object-side surface S7 is concave, and its image-side surface S8 is concave. The fifth lens E5 has positive optical power, its object-side surface S9 is concave, and its image-side surface S10 is convex. The sixth lens E6 has negative optical power, its object-side surface S11 is convex, and its image-side surface S12 is concave. In Table 5, OBJ (not shown in the figure) is the object plane of the optical imaging system; S13 and S14 (not shown in the figure) can be the object-side and image-side surfaces of the filter or protective glass; S15 (not shown in the figure) is the imaging plane of the optical imaging system; and STO (not shown in the figure) is the aperture stop, located between the second lens E2 and the third lens E3. Light rays from the object plane pass through S1 to S14 to reach S15 (the imaging plane).

[0133] Table 5 shows the basic structural parameters of the optical imaging system in Embodiment 3, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0134] Table 5

[0135]

[0136] Table 6 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 that can be used for each aspherical mirror S1-S12 in Example 3. Among them, each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0137] Table 6

[0138]

[0139] Figure 17 The on-axis chromatic aberration curve of the optical imaging system of Embodiment 3 is shown, which represents the deflection of the focal point after light of different wavelengths passes through the optical imaging system. Figure 18 The astigmatism curves of the optical imaging system of Embodiment 3 are shown, which represent the curvature of the meridional image plane and the curvature of the sagittal image plane. Figure 19 The distortion curves of the optical imaging system of Embodiment 3 are shown, which represent the distortion magnitude values ​​corresponding to different field of view angles.

[0140] according to Figures 17 to 19As can be seen, the optical imaging system given in Example 3 can achieve good imaging quality.

[0141] In summary, the optical imaging systems of Examples 1 to 3 respectively satisfy the relationships shown in Table 7.

[0142] Table 7

[0143]

[0144] Table 8 shows some parameters of the optical imaging systems of Embodiments 1 to 3. Wherein, Fno is the aperture value of the optical imaging system, Semi-FOV is half of the maximum field of view of the optical imaging system, f is the effective focal length of the optical imaging system, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, and f6 is the effective focal length of the sixth lens.

[0145] Table 8

[0146]

[0147] 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.

[0148] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0149] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0150] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0151] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical imaging system, characterized in that, It includes a lens barrel and a lens assembly and multiple spacer elements disposed within the lens barrel. The lens group consists of six lenses, including a first lens with positive optical power, a second lens with optical power, a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, and a sixth lens with negative optical power, arranged sequentially from the object side to the image side along the optical axis of the optical imaging system. The image side of the first lens is convex, the image side of the fourth lens is concave, the object side of the fifth lens is concave, and the image side of the fifth lens is convex. There is an air gap between adjacent lenses in the lens group. The plurality of spacers includes at least a first spacer, a second spacer, a third spacer, a fourth spacer, and a fifth spacer. The first spacer is located between the first lens and the second lens and is in contact with the image-side surface of the first lens. The second spacer is located between the second lens and the third lens and is in contact with the image-side surface of the second lens. The third spacer is located between the third lens and the fourth lens and is in contact with the image-side surface of the third lens. The fourth spacer is located between the fourth lens and the fifth lens and is in contact with the image-side surface of the fourth lens. The fifth spacer is located between the fifth lens and the sixth lens and is in contact with the image-side surface of the fifth lens. The distance TD between the object-side surface of the first lens and the image-side surface of the sixth lens in the optical axis direction, the effective focal length f of the optical imaging system, and half of the maximum field of view (Semi-FOV) of the optical imaging system satisfy the following condition: 1.90 ≤ TD / f × tan(Semi-FOV) < 2.10; The inner diameter d0m of the image-side end face of the lens tube, the inner diameter d0s of the object-side end face of the lens tube, and the effective focal length f of the optical imaging system satisfy the following condition: 0.85 < (d0m - d0s) / f ≤ 1.

05.

2. The optical imaging system according to claim 1, characterized in that, The maximum height L of the microscope tube and the outer diameter D0s of the object-side end face of the microscope tube satisfy the following relationship: 0.75 <L / D0s<0.90。 3. The optical imaging system according to claim 1, characterized in that, Among the plurality of spacers, the second spacer has the smallest inner diameter. The central thickness CT3 of the third lens on the optical axis of the optical imaging system, the central thickness CT2 of the second lens on the optical axis, and the inner diameter d2s of the object side of the second spacer satisfy the following: 0.20 < (CT3 - CT2) / d2s < 0.

35.

4. The optical imaging system according to claim 1, characterized in that, The outer diameter D1s of the object side of the first spacer element, the inner diameter d1s of the object side of the first spacer element, and the effective diameter DT12 of the object side of the first lens satisfy the following condition: 1.15 < (D1s - d1s) / DT12 < 1.

65.

5. The optical imaging system according to claim 1, characterized in that, The inner diameter d3s of the object side of the third spacer, the inner diameter d2m of the image side of the second spacer, and the effective focal length f3 of the third lens satisfy the following condition: 0.05≤(d3s-d2m) / f3<0.

30.

6. The optical imaging system according to claim 1, characterized in that, The object side of the third lens is convex, the image side of the third lens is convex, and the following condition is satisfied among the radius of curvature R5 of the object side of the third lens, the radius of curvature R6 of the image side of the third lens, and the distance EP23 in the optical axis direction between the image side of the second spacer element and the object side of the third spacer element: 11.00 < (R5 + R6) / EP23 < 54.

50.

7. The optical imaging system according to claim 1, characterized in that, The following condition is satisfied among the outer diameter D4m of the image side of the fourth spacer element, the inner diameter d4s of the object side of the fourth spacer element, the effective focal length f5 of the fifth lens, and the effective focal length f4 of the fourth lens: 0.10 < (D4m - d4s) / (f5 - f4) ≤ 0.

50.

8. The optical imaging system according to claim 1, characterized in that, The following condition is satisfied among the outer diameter D5m of the image side of the fifth spacer element, the inner diameter d5m of the image side of the fifth spacer element, and the effective focal length f6 of the sixth lens: -1.80 < (D5m - d5m) / f6 < -0.

25.

9. The optical imaging system according to any one of claims 1 to 8, characterized in that, Among the lenses in the lens group, the center thickness of the fifth lens on the optical axis of the optical imaging system is the largest, and the following condition is satisfied between the center thickness CT5 of the fifth lens on the optical axis and the distance EP45 in the optical axis direction between the image side of the fourth spacer element and the object side of the fifth spacer element: 1.15 < CT5 / EP45 < 3.

05.

10. The optical imaging system according to any one of claims 1 to 8, characterized in that, When the following condition is satisfied between the center thickness CT5 of the fifth lens on the optical axis of the optical imaging system and the distance EP45 in the optical axis direction between the image side of the fourth spacer element and the object side of the fifth spacer element: 1.55 < CT5 / EP45 < 3.05, the plurality of spacer elements further includes a fifth auxiliary spacer element, and the fifth auxiliary spacer element is located between the fifth lens and the sixth lens and contacts the image side of the fifth spacer element.

11. The optical imaging system according to claim 10, characterized in that, The following condition is satisfied among the maximum axial thickness CP5 of the fifth spacer element, the maximum axial thickness CP5b of the fifth auxiliary spacer element, the radius of curvature R11 of the object side of the sixth lens, and the radius of curvature R10 of the image side of the fifth lens: 0.10 < (CP5 + CP5b) / (R11 - R10) ≤ 0.20.

Images