Internal focusing lens system

Abstract

The utility model discloses an internal focusing lens system, which comprises a lens barrel assembly and an optical lens group, and is characterized in that the lens barrel assembly comprises a first lens barrel, a second lens barrel and a third lens barrel which are sequentially arranged from an object side to an image plane along an optical axis; the optical lens group sequentially comprises a first lens group, a second lens group, a third lens group and a fourth lens group from the object side to the image plane along the optical axis, the second lens group is arranged in the second lens barrel, has positive focal power and comprises a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens and a sixth lens with positive focal power; the third lens group is arranged in the third lens barrel and comprises a seventh lens with negative focal power; the inner focusing lens system satisfies: 0 lt; (F2 + F3) / F1lt; 0.2, 1.3 < = F2 / L2 < = 1.5, 1.5 lt; f3 / L3 < = 2.2, F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, F3 is the effective focal length of the third lens group, L2 is the length of the second lens barrel in the direction of the optical axis, and L3 is the length of the third lens barrel in the direction of the optical axis.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and in particular to an inner focusing lens system composed of three lens groups. Background Art

[0002] In recent years, smart products have been rapidly updated and iterated, and the lens used for taking photos and videos is the focus of the update and iteration. Taking a smartphone as an example, a mobile phone is usually equipped with a front small lens and a rear telephoto, wide-angle, and ultra-wide-angle lens, so as to meet the shooting needs of multiple scenes and multiple focal lengths. The switching and zooming of different lenses in a smartphone are often achieved by digital zoom. However, the digital zoom process will cause image quality loss, thus affecting the overall imaging effect. Utility Model Content

[0003] The present application provides an inner focus lens system that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0004] One aspect of the present application provides such an inner focusing lens system, which includes a lens barrel assembly and an optical lens group, wherein the lens barrel assembly includes a first lens barrel, a second lens barrel and a third lens barrel arranged in sequence from the object side to the image plane along the optical axis; wherein the optical lens group includes in sequence from the object side to the image plane along the optical axis: a first lens group disposed in the first lens barrel, including a first lens with optical power; a second lens group disposed in the second lens barrel and having positive optical power, including a second lens with positive optical power, a third lens with negative optical power, a fourth lens with negative optical power, a fifth lens with optical power and a sixth lens with positive optical power; and a lens group disposed in the third lens barrel The third lens group inside includes a seventh lens with negative optical power; the positions of the first lens group and the third lens group relative to the image plane on the optical axis are fixed, and the distance of the second lens group relative to the first lens group on the optical axis is adjustable; the inner focusing lens system satisfies: 0<(F2+|F3|) / |F1|<0.2, 1.3≤F2 / L2≤1.5, 1.5<|F3| / L3≤2.2, wherein F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, F3 is the effective focal length of the third lens group, L2 is the length of the second lens barrel along the direction of the optical axis, and L3 is the length of the third lens barrel along the direction of the optical axis.

[0005] According to an exemplary embodiment of the present application, the entrance pupil diameter EPD of the inner focus lens system, the inner diameter d01m of the image side end surface of the first lens barrel and the inner diameter d02s of the object side end surface of the second lens barrel satisfy: 1.5 <EPD / (d01m-d02s)≤2.1。

[0006] According to an exemplary embodiment of the present application, the outer diameter D01m of the image side end surface of the first lens barrel, the inner diameter d01s of the object side end surface of the first lens barrel and the length L1 of the first lens barrel along the optical axis direction satisfy: 1.0≤(D01m-d01s) / L1≤1.3.

[0007] According to an exemplary embodiment of the present application, the outer diameter D03m of the image side end surface of the third lens barrel, the inner diameter d03s of the object side end surface of the third lens barrel and the length L3 of the third lens barrel along the direction of the optical axis satisfy: 1.0≤L3 / (D03m-d03s)≤1.3.

[0008] According to an exemplary embodiment of the present application, the effective focal length F3 of the third lens group, the outer diameter D03s of the object side end surface of the third lens barrel, and the inner diameter d03s of the object side end surface of the third lens barrel satisfy: -2.5 <F3 / (D03s-d03s)≤-2.0。

[0009] According to an exemplary embodiment of the present application, the effective focal length F3 of the third lens group, the length L3 of the third lens barrel along the direction of the optical axis, and the center thickness CT7 of the seventh lens on the optical axis satisfy: -3.0 <F3 / (L3-CT7)<-2.3。

[0010] According to an exemplary embodiment of the present application, the effective focal length F2 of the second lens group, the effective focal length F3 of the third lens group and the maximum movable distance ΔEP0 of the second lens barrel along the optical axis direction satisfy: 38<(F2+|F3|) / ΔEP0<45.

[0011] According to an exemplary embodiment of the present application, the sum ∑T13 of the air interval on the optical axis between the first lens and the second lens and the air interval on the optical axis between the sixth lens and the seventh lens and the maximum movable distance ΔEP0 of the second lens barrel along the optical axis direction satisfies: 7≤∑T13 / ΔEP0<8.0.

[0012] According to an exemplary embodiment of the present application, the inner focusing lens system further includes a second spacer disposed on the image side of the second lens and in contact with the image side of the second lens, wherein the effective focal length f2 of the second lens, the air interval T23 between the second lens and the third lens on the optical axis, the object side end surface of the second lens barrel, and the interval EP022 of the second spacer along the optical axis satisfy: 5.5 <f2 / (EP022-T23)≤8.0。

[0013] According to an exemplary embodiment of the present application, the inner focusing lens system further includes a second spacer disposed on the image side of the second lens and in contact with the image side of the second lens, and a third spacer disposed on the image side of the third lens and in contact with the image side of the third lens, wherein the interval EP23 between the second spacer and the third spacer along the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis, and the refractive index N3 of the third lens satisfy: 1.0 <EP23 / (T34×(N3-1))<1.5。

[0014] According to an exemplary embodiment of the present application, the internal focusing lens system also includes a third spacer disposed on the image side surface of the third lens and in contact with the image side surface of the third lens, and a fourth spacer disposed on the image side surface of the fourth lens and in contact with the image side surface of the fourth lens, wherein the interval EP34 between the third spacer and the fourth spacer along the optical axis, the air interval T45 between the fourth lens and the fifth lens on the optical axis, and the center thickness CT4 of the fourth lens on the optical axis satisfy: 0.1≤(EP34-T45) / CT4<1.5.

[0015] According to an exemplary embodiment of the present application, the internal focusing lens system also includes a fourth spacer disposed on the image side surface of the fourth lens and in contact with the image side surface of the fourth lens, and a fifth spacer disposed on the image side surface of the fifth lens and in contact with the image side surface of the fifth lens, wherein the interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the maximum thickness CP5 of the fifth spacer, and the air interval T56 between the fifth lens and the sixth lens on the optical axis satisfy: 1.5≤(EP45+CP5) / T56<3.5.

[0016] The internal focus lens system provided by the present application includes three lens groups, and the three lens groups are respectively assembled in three lens barrels, and the focus adjustment of the internal focus lens system can be achieved by moving the second lens group. When the internal focus lens system satisfies "0<(F2+|F3|) / |F1|<0.2", the ratio of the effective focal length of the second lens group to the length of the second lens barrel along the direction where the optical axis is located and the ratio of the effective focal length of the third lens group to the length of the third lens barrel along the direction where the optical axis is located are reasonably configured, so that the focusing degree of the three lens groups can be effectively allocated, the feasibility of the zoom of the second lens group can be ensured, and the on-axis distance of the second lens group and the third lens group can be effectively regulated, so as to prevent the second lens group from colliding with the first lens group or the third lens group during the zooming process of the internal focus lens system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings, in which:

[0018] Figure 1shows a parameter annotation diagram of an inner focus lens system according to the present application;

[0019] Figure 2 A schematic structural diagram of an optical lens assembly according to Embodiment 1, 2 or 3 of the present application is shown;

[0020] Figure 3 A schematic structural diagram of an inner focus lens system according to Embodiment 1 of the present application is shown;

[0021] Figure 4 A schematic structural diagram of an inner focus lens system according to Embodiment 2 of the present application is shown;

[0022] Figure 5 A schematic structural diagram of an inner focus lens system according to Embodiment 3 of the present application is shown;

[0023] FIG. 6A to FIG. 6C The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the inner focus lens system of Embodiment 1, 2 or 3 of the present application in a telephoto state (for example, the distance of the object from the inner focus lens system is infinite) are respectively shown;

[0024] 7A to 7C The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the inner focus lens system in the close-up state (for example, the distance of the object from the inner focus lens system is 150 mm) of Embodiment 1, 2 or 3 of the present application are respectively shown;

[0025] Figure 8 A schematic structural diagram of an optical lens assembly according to Embodiment 4, 5 or 6 of the present application is shown;

[0026] Fig. 9 A schematic structural diagram of an inner focus lens system according to Embodiment 4 of the present application is shown;

[0027] Fig.10 A schematic structural diagram of an inner focus lens system according to Embodiment 5 of the present application is shown;

[0028] Fig.11 A schematic structural diagram of an inner focus lens system according to Embodiment 6 of the present application is shown;

[0029] FIG. 12A to FIG. 12C The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the inner focus lens system of Embodiment 4, 5 or 6 of the present application in a telephoto state (for example, the distance of the object from the inner focus lens system is infinite) are respectively shown;

[0030] FIG. 13A to FIG. 13C The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the inner focus lens system of Embodiment 4, 5 or 6 of the present application in a close-up state (for example, the distance of the object from the inner focus lens system is 150 mm) are respectively shown;

[0031] Fig.14 A schematic structural diagram of an optical lens assembly according to Embodiment 7, 8 or 9 of the present application is shown;

[0032] Fig.15 A schematic structural diagram of an inner focus lens system according to Embodiment 7 of the present application is shown;

[0033] Fig.16 A schematic structural diagram of an inner focus lens system according to Embodiment 8 of the present application is shown;

[0034] Fig.17 A schematic structural diagram of an inner focus lens system according to Embodiment 9 of the present application is shown;

[0035] 18A to 18C The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the inner focus lens system of Embodiment 7, 8 or 9 of the present application in a telephoto state (for example, the distance of the subject from the inner focus lens system is infinite) are respectively shown; and

[0036] FIG. 19A to FIG. 19C The axial chromatic aberration curve, astigmatism curve and distortion curve of the close-up state of the inner focus lens system of Embodiment 7, 8 or 9 of the present application (for example, the distance of the subject from the inner focus lens system is 150 mm) are respectively shown. DETAILED DESCRIPTION

[0037] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numerals refer to the same elements.

[0038] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0039] In the 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 shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0040] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the image plane is called the image side of the lens.

[0041] It should also be understood that the terms "including" and / or "having", 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. In addition, when describing the embodiments of the present application, the term "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0042] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0043] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] Figure 1 FIG. 1 is a parameter annotation diagram of an inner focus lens system according to an exemplary embodiment of the present application. Figure 1 , L1 represents the length of the first lens barrel along the direction of the optical axis, L2 represents the length of the second lens barrel along the direction of the optical axis, L3 represents the length of the third lens barrel along the direction of the optical axis, d01s represents the inner diameter of the object side end surface of the first lens barrel, d01m represents the inner diameter of the image side end surface of the first lens barrel, D01m represents the outer diameter of the image side end surface of the first lens barrel, d02s represents the inner diameter of the object side end surface of the second lens barrel, d03s represents the inner diameter of the object side end surface of the third lens barrel, and D03s represents the outer diameter of the object side end surface of the third lens barrel. The outer diameter of the end face, D03m represents the outer diameter of the image side end face of the third lens barrel, ΔEP0 represents the maximum movable distance of the second lens barrel along the optical axis, EP022 represents the interval between the object side end face of the second lens barrel and the second spacer along the optical axis, EP23 represents the interval between the second spacer and the third spacer along the optical axis, EP34 represents the interval between the third spacer and the fourth spacer along the optical axis, EP45 represents the interval between the fourth spacer and the fifth spacer along the optical axis, and CP5 represents the maximum thickness of the fifth spacer.

[0045] refer to Figures 2 to 5 , Figures 8 to 11 as well as Figures 14 to 17 In a first aspect of the present application, an inner focusing lens system is provided. The inner focusing lens system may include an optical lens group, and the optical lens group may include a first lens group, a second lens group, and a third lens group arranged in sequence from the object side to the image plane along the optical axis. In the first lens group to the third lens group, any two adjacent lens groups may have an air gap between them.

[0046] The positions of the first lens group and the third lens group on the optical axis relative to the image plane are fixed. The second lens group can move relative to the first lens group along the optical axis, that is, the distance of the second lens group relative to the first lens group on the optical axis is adjustable. When the distance of the object to be photographed from the inner focus lens system changes from far to near, the distance between the second lens group and the first lens group on the optical axis is adjusted, so that the inner focus lens system can be switched between the telephoto state and the close-up state, thereby realizing the focus adjustment of the inner focus lens system.

[0047] In an exemplary embodiment, the inner focus lens system may further include a lens barrel assembly, which may include a first lens barrel, a second lens barrel, and a third lens barrel arranged in sequence from the object side to the image plane along the optical axis. The first lens group may be placed in the first lens barrel. The second lens group may be placed in the second lens barrel. The third lens group may be placed in the third lens barrel. Accordingly, the first lens barrel and the third lens barrel are fixed assemblies, and their positions relative to the image plane are fixed; the second lens barrel is a moving assembly, which can move with the movement of the second lens group during the zooming process of the inner focus lens system.

[0048] In example embodiments, the first lens group may include a first lens having optical power.

[0049] In an exemplary embodiment, the second lens group may have positive power and include, in order from the object side to the image plane along the optical axis, a second lens having positive power, a third lens having negative power, a fourth lens having negative power, a fifth lens having power, and a sixth lens having positive power.

[0050] In example embodiments, the third lens group may include a seventh lens having negative power.

[0051] In an exemplary embodiment, the inner focus lens system may further include one or more of a second spacer, a third spacer, a fourth spacer, and a fifth spacer. The second spacer may be placed on the image side of the second lens and at least partially contact the image side of the second lens. The third spacer may be placed on the image side of the third lens and at least partially contact the image side of the third lens. The fourth spacer may be placed on the image side of the fourth lens and at least partially contact the image side of the fourth lens. The fifth spacer may be placed on the image side of the fifth lens and at least partially contact the image side of the fifth lens. Reasonable use of spacers can effectively avoid stray light risks, reduce interference with image quality, and thereby improve the imaging quality of the inner focus lens system. In the example, the second spacer, the third spacer, the fourth spacer, and the fifth spacer may be placed in the second lens barrel.

[0052] In an exemplary embodiment, the second lens group may further include a stop disposed between the object side and the second lens.

[0053] In an exemplary embodiment, the effective focal length F1 of the first lens group, the effective focal length F2 of the second lens group, and the effective focal length F3 of the third lens group may satisfy: 0<(F2+|F3|) / |F1|<0.2. Reasonable allocation of the effective focal lengths of the first lens group, the second lens group, and the third lens group is conducive to improving the imaging quality of the inner focus lens system.

[0054] In an exemplary embodiment, the effective focal length F2 of the second lens group and the length L2 of the second lens barrel along the direction of the optical axis may satisfy: 1.3≤F2 / L2≤1.5, and the effective focal length F3 of the third lens group and the length L3 of the third lens barrel along the direction of the optical axis may satisfy: 1.5<|F3| / L3≤2.2. When the inner focus lens system satisfies "0<(F2+|F3|) / |F1|<0.2", the ratio of the effective focal length of the second lens group to the length of the second lens barrel along the direction of the optical axis and the ratio of the effective focal length of the third lens group to the length of the third lens barrel along the direction of the optical axis are reasonably configured, so that the focusing degree of the three lens groups can be effectively distributed, the feasibility of the zooming of the second lens group can be ensured, and the on-axis distance of the second lens group and the third lens group can be effectively regulated, so as to prevent the second lens group from colliding with the first lens group or the third lens group during the zooming process of the inner focus lens system.

[0055] In an exemplary embodiment, the entrance pupil diameter EPD of the internal focusing lens system, the inner diameter d01m of the image-side end face of the first lens barrel, and the inner diameter d02s of the object-side end face of the second lens barrel may satisfy: 1.5 < EPD / (d01m - d02s) ≤ 2.1. By reasonably configuring the ratio of the entrance pupil diameter of the internal focusing lens system to the difference between the inner diameters of the image-side end face of the first lens barrel and the object-side end face of the second lens barrel, when the entrance pupil diameter of the internal focusing lens system is fixed, it is possible to better match the image-side end face of the first lens barrel and the object-side end face of the second lens barrel, avoiding light blocking at the image-side end face of the first lens barrel and affecting the main value parameters of the internal focusing lens system; it can also ensure that while the internal focusing lens system has a large aperture under a certain lens barrel assembly space, light leakage caused by an overly large entrance pupil diameter is avoided, thereby improving the imaging quality of the internal focusing lens system.

[0056] In an exemplary embodiment, the outer diameter D01m of the image-side end face of the first lens barrel, the inner diameter d01s of the object-side end face of the first lens barrel, and the length L1 of the first lens barrel in the direction of the optical axis may satisfy: 1.0 ≤ (D01m - d01s) / L1 ≤ 1.3. By reasonably configuring the ratio of the difference between the outer diameter of the image-side end face and the inner diameter of the object-side end face of the first lens barrel to the length of the first lens barrel in the direction of the optical axis, it is possible to make the thickness of the first lens barrel uniform in the axial and vertical directions, improving the forming feasibility of the first lens barrel; at the same time, it can also avoid problems such as excessive occupation of the lens group space caused by an overly large length of the first lens barrel in the direction of the optical axis and easy interference between the first lens barrel and the second lens group during the zooming process of the internal focusing lens system, or avoid the problem of the first lens protruding outward due to an overly small length of the first lens barrel in the direction of the optical axis.

[0057] In an exemplary embodiment, the outer diameter D03m of the image-side end face of the third lens barrel, the inner diameter d03s of the object-side end face of the third lens barrel, and the length L3 of the third lens barrel in the direction of the optical axis may satisfy: 1.0 ≤ L3 / (D03m - d03s) ≤ 1.3. By reasonably configuring the ratio of the length of the third lens barrel in the direction of the optical axis to the difference between the outer diameter of the image-side end face and the inner diameter of the object-side end face of the third lens barrel, it is possible to make the thickness of the third lens barrel uniform in the axial and vertical directions, improving the forming feasibility of the third lens barrel; at the same time, it can also avoid problems such as excessive occupation of the lens group space caused by an overly large length of the third lens barrel in the direction of the optical axis and easy interference between the third lens barrel and the second lens group during the zooming process of the internal focusing lens system, or avoid the problem of the seventh lens protruding outward due to an overly small length of the third lens barrel in the direction of the optical axis.

[0058] In an exemplary embodiment, the effective focal length F3 of the third lens group, the outer diameter D03s of the object-side end face of the third lens barrel, and the inner diameter d03s of the object-side end face of the third lens barrel may satisfy: -2.5 < F3 / (D03s - d03s) ≤ -2.0. By reasonably configuring the ratio of the effective focal length of the third lens group to the difference between the outer and inner diameters of the object-side end face of the third lens barrel, the field light passing through the third lens group can be better transitioned, so that the exit angle of the light exiting from the third lens group can better match the chip; at the same time, the difference between the outer diameter and the inner diameter of the object-side end face of the third lens barrel can be constrained within a certain range, ensuring that the seventh lens can be better assembled and supported in the third lens barrel, and avoiding deformation caused by the seventh lens being too large.

[0059] In an exemplary embodiment, the effective focal length F3 of the third lens group, the length L3 of the third lens barrel in the direction of the optical axis, and the central thickness CT7 of the seventh lens on the optical axis may satisfy: -3.0 < F3 / (L3 - CT7) < -2.3. By controlling the above conditional expression, while making the effective focal length of the third lens group negative, the ratio of the central thickness of the seventh lens to the length of the third lens barrel in the direction of the optical axis can be constrained within a certain range, avoiding the problem of insufficient structural strength of the seventh lens caused by the central thickness of the seventh lens being too small. At the same time, space can be reserved for the non-effective diameter part of the seventh lens, improving the forming feasibility of the seventh lens.

[0060] In an exemplary embodiment, the effective focal length F2 of the second lens group, the effective focal length F3 of the third lens group, and the maximum movable distance ΔEP0 of the second lens barrel in the optical axis direction may satisfy: 38 < (F2 + |F3|) / ΔEP0 < 45. By controlling the above conditional expression, the sum of the absolute values of the effective focal lengths of the second lens group and the third lens group can be constrained within a reasonable range, effectively distributing the focusing degree between the second lens group and the third lens group, ensuring the zoom feasibility of the second lens group; at the same time, the maximum movable distance of the second lens barrel in the optical axis direction can be limited, thereby effectively regulating the axial zoom distance of the second lens group and preventing the second lens barrel from colliding with the first lens barrel during the zoom process of the internal focusing lens system.

[0061] In an exemplary embodiment, the sum ∑T13 of the air spaces on the optical axis between the first lens and the second lens and between the sixth lens and the seventh lens and the maximum movable distance ΔEP0 of the second lens barrel in the optical axis direction may satisfy: 7 ≤ ∑T13 / ΔEP0 < 8.0. Reasonably configuring the ratio of the sum of the air spaces on the optical axis between any two adjacent lens groups among the first lens group to the third lens group to the maximum movable distance of the second lens barrel in the optical axis direction can ensure that there is sufficient space distance between the second lens group and the first lens group and the third lens group during the zooming process of the internal focusing lens system, avoiding interference between adjacent lens groups; at the same time, it can also leave enough space for these three lens groups during module assembly, avoiding interference during the assembly of these three lens groups.

[0062] In an exemplary embodiment, the effective focal length f2 of the second lens, the air space T23 between the second lens and the third lens on the optical axis, and the space EP022 between the object-side end face of the second lens barrel and the second spacer along the optical axis may satisfy: 5.5 < f2 / (EP022 - T23) ≤ 8.0. Reasonably configuring the mutual relationship between the effective focal length of the second lens, the space between the object-side end face of the second lens barrel and the second spacer along the optical axis, and the air space between the second lens and the third lens on the optical axis can, when the effective focal length of the second lens is fixed, make the bearing thickness of the second lens barrel and the edge thickness of the second lens fall within a certain range, improving the forming feasibility of the second lens barrel and the second lens.

[0063] In an exemplary embodiment, the space EP23 between the second spacer and the third spacer along the optical axis, the air space T34 between the third lens and the fourth lens on the optical axis, and the refractive index N3 of the third lens may satisfy: 1.0 < EP23 / (T34×(N3 - 1)) < 1.5. Reasonably configuring the mutual relationship between the space between the second spacer and the third spacer along the optical axis, the air space between the third lens and the fourth lens on the optical axis, and the refractive index of the third lens can constrain the edge thickness of the third lens within a certain range, ensuring that the edge thickness of the third lens meets the forming requirements and improving the forming feasibility of the third lens; at the same time, it can also limit the air space between the third lens and the fourth lens on the optical axis, ensuring the stability of the intermediate gap when the third lens and the fourth lens are assembled, and improving the imaging field curvature stability of the internal focusing lens system.

[0064] In an exemplary embodiment, the interval EP34 between the third spacer and the fourth spacer along the optical axis, the air interval T45 between the fourth lens and the fifth lens on the optical axis, and the center thickness CT4 of the fourth lens on the optical axis may satisfy: 0.1≤(EP34-T45) / CT4<1.5. Reasonable configuration of the relationship between the interval between the third spacer and the fourth spacer along the optical axis, the air interval between the fourth lens and the fifth lens on the optical axis, and the center thickness of the fourth lens on the optical axis is conducive to constraining the ratio of the center thickness to the edge thickness of the fourth lens within a certain range, ensuring the processability and assembly feasibility of the fourth lens, and avoiding the problem that the fourth lens cannot be processed due to the edge being too thin or the assembly step is too large due to the edge being too thick, which affects the assembly of the fourth lens.

[0065] In an exemplary embodiment, the interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the maximum thickness CP5 of the fifth spacer, and the air interval T56 between the fifth lens and the sixth lens on the optical axis can satisfy: 1.5≤(EP45+CP5) / T56<3.5. Reasonable configuration of the relationship between the interval between the fourth spacer and the fifth spacer along the optical axis, the maximum thickness of the fifth spacer, and the air interval between the fifth lens and the sixth lens on the optical axis is conducive to limiting the overall maximum thickness of the fifth lens and the size of the edge axial step difference, ensuring the overall uniformity of the fifth lens; at the same time, the maximum thickness of the fifth spacer can be constrained within a certain range, and when the step difference between the fifth lens and the sixth lens is too large, the problem of insufficient structural strength of the fifth spacer caused by the maximum thickness of the fifth spacer is avoided, thereby improving the assembly stability of the inner focusing lens system.

[0066] According to the above-mentioned embodiment of the present application, the inner focus lens system can use seven lenses, three lens barrels, and at least one spacer. By reasonably allocating the parameters of each lens, each lens barrel, and each spacer, the zoom feasibility of the second lens group can be guaranteed, and the second lens group can be prevented from interfering with the first lens group and the third lens group during the zoom process of the inner focus lens system, and the molding feasibility, assembly stability, and imaging quality of the inner focus lens system can also be improved.

[0067] In an embodiment of the present application, at least one of the surfaces of each lens in the first lens to the seventh lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, the object side surface and the image side surface of each lens in the first lens to the seventh lens are both aspherical surfaces.

[0068] The second aspect of the present application provides an internal focusing lens system, which includes a lens barrel assembly and an optical lens group. The lens barrel assembly includes a first lens barrel, a second lens barrel, and a third lens barrel arranged in sequence along the optical axis from the object side to the image plane. The optical lens group includes, in sequence along the optical axis from the object side to the image plane: a first lens group disposed in the first lens barrel, including a first lens having a focal power; a second lens group disposed in the second lens barrel and having a positive focal power, including a second lens having a positive focal power, a third lens having a negative focal power, a fourth lens having a negative focal power, a fifth lens having a focal power, and a sixth lens having a positive focal power; and a third lens group disposed in the third lens barrel, including a seventh lens having a negative focal power. The positions of the first lens group and the third lens group on the optical axis relative to the image plane are fixed, and the distance of the second lens group on the optical axis relative to the first lens group is adjustable.

[0069] Wherein, the entrance pupil diameter EPD of the internal focusing lens system, the inner diameter d01m of the image-side end face of the first lens barrel, and the inner diameter d02s of the object-side end face of the second lens barrel can satisfy: 1.5 < EPD / (d01m - d02s) ≤ 2.1. The internal focusing lens system provided by the present application includes three lens groups, and the three lens groups are respectively assembled in three lens barrels. By moving the second lens group, the focusing of the internal focusing lens system can be achieved. At the same time, by reasonably configuring the ratio of the entrance pupil diameter of the internal focusing lens system to the difference between the inner diameters of the image-side end face of the first lens barrel and the object-side end face of the second lens barrel, when the entrance pupil diameter of the internal focusing lens system is certain, it can make the image-side end face of the first lens barrel and the object-side end face of the second lens barrel better match, avoiding light blocking by the image-side end face of the first lens barrel and affecting the main value parameters of the internal focusing lens system; it can also ensure that while the internal focusing lens system realizes a large aperture, light leakage caused by an overly large entrance pupil diameter is avoided when the space of the lens barrel assembly is certain, thereby improving the imaging quality of the internal focusing lens system.

[0070] The third aspect of the present application provides an internal focusing lens system, which includes a lens barrel assembly and an optical lens group. The lens barrel assembly includes a first lens barrel, a second lens barrel, and a third lens barrel arranged in sequence along the optical axis from the object side to the image plane. The optical lens group includes, in sequence along the optical axis from the object side to the image plane: a first lens group disposed in the first lens barrel, including a first lens having a focal power; a second lens group disposed in the second lens barrel and having a positive focal power, including a second lens having a positive focal power, a third lens having a negative focal power, a fourth lens having a negative focal power, a fifth lens having a focal power, and a sixth lens having a positive focal power; and a third lens group disposed in the third lens barrel, including a seventh lens having a negative focal power. The positions of the first lens group and the third lens group on the optical axis relative to the image plane are fixed, and the distance of the second lens group on the optical axis relative to the first lens group is adjustable.

[0071] Among them, the effective focal length F2 of the second lens group, the effective focal length F3 of the third lens group and the maximum movable distance ΔEP0 of the second lens barrel along the optical axis direction can satisfy: 38<(F2+|F3|) / ΔEP0<45. The internal focus lens system provided in the present application includes three lens groups, and the three lens groups are respectively assembled in three lens barrels. The focus adjustment of the internal focus lens system can be achieved by moving the second lens group. At the same time, by controlling the internal focus lens system to satisfy "38<(F2+|F3|) / ΔEP0<45", the sum of the absolute values ​​of the effective focal length of the second lens group and the effective focal length of the third lens group can be constrained within a reasonable range, the focusing degree between the second lens group and the third lens group can be effectively allocated, and the zoom feasibility of the second lens group can be ensured; at the same time, the maximum movable distance of the second lens barrel along the optical axis direction can be limited, thereby effectively regulating the axial zoom distance of the second lens group and preventing the second lens barrel from colliding with the first lens barrel during the zooming process of the internal focus lens system.

[0072] Those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses and spacers constituting the inner focusing lens system can be changed to obtain the various results and advantages described in this specification.

[0073] Specific embodiments of the inner focus lens system applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0074] Example 1

[0075] The following reference Figure 2 and Figure 3 An inner focus lens system according to Embodiment 1 of the present application is described.

[0076] like Figure 2 and Figure 3 As shown, the inner focus lens system includes a lens barrel assembly and an optical lens group. The lens barrel assembly includes a first lens barrel P01, a second lens barrel P02 and a third lens barrel P03 arranged in sequence from the object side to the image plane along the optical axis.

[0077] The optical lens group includes a first lens group G1 placed in the first lens barrel P01, a second lens group G2 placed in the second lens barrel P02 and having positive focal power, and a third lens group G3 placed in the third lens barrel P03 and having negative focal power in order from the object side to the image plane along the optical axis. The first lens group G1 and the third lens group G3 are fixed relative to the image plane on the optical axis. The second lens group G2 can move relative to the first lens group G1 along the optical axis. When the inner focusing lens system is from far to near at the distance of the object, adjusting the distance between the second lens group G2 and the first lens group G1 on the optical axis can switch the inner focusing lens system between the telephoto state and the close-up state, thereby realizing the focus adjustment of the inner focusing lens system. In the example, the first lens group G1 includes a first lens E1. The second lens group G2 includes a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image plane along the optical axis. The third lens group G3 includes a seventh lens E7. The second lens group G2 further includes a stop STO, which is disposed between the object side and the second lens E2.

[0078] The first lens E1 has negative focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive focal power, and its object side surface S3 is convex, and its image side surface S4 is convex. The third lens E3 has negative focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has negative focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has negative focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. A filter E8 is also arranged between the seventh lens E7 and the image surface S17, and the filter E8 has an object side surface S15 and an image side surface S16. Light from the object passes through the surfaces S1 to S16 in sequence and is finally imaged on the image plane S17.

[0079] The inner focus lens system includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second lens barrel P02. The spacers can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the second lens barrel P02 better supported, thereby enhancing the structural stability of the inner focus lens system.

[0080] Table 1 shows the basic parameters of the inner focus lens system of Example 1, wherein the units of the curvature radius, thickness / distance, and focal length are all millimeters (mm).

[0081]

[0082] Table 1

[0083] In this embodiment, the object side surface and the image side surface of any lens among the first lens E1 to the seventh lens E7 are both aspherical surfaces, and the surface shape x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0084]

[0085] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 shows the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0086] Face number A4 A6 A8 A10 A12 A14 A16 S1 -4.3319E-03 -1.9088E-04 6.8345E-05 -1.3657E-05 1.9734E-06 -1.7814E-07 8.7244E-09 S2 -4.2176E-03 -4.1688E-04 1.6687E-04 -4.1040E-05 6.8678E-06 -7.0866E-07 3.9982E-08 S3 1.4678E-03 -5.2892E-04 4.3603E-04 -2.2941E-04 8.0752E-05 -1.8400E-05 2.6527E-06 S4 -3.8724E-03 7.2404E-03 -5.6443E-03 2.9219E-03 -1.0182E-03 2.3444E-04 -3.3959E-05 S5 -1.4032E-02 9.8207E-03 -6.2320E-03 3.0136E-03 -1.0277E-03 2.3712E-04 -3.5019E-05 S6 -1.1513E-02 5.0946E-03 -2.4565E-03 1.3043E-03 -5.8904E-04 1.9425E-04 -4.1265E-05 S7 -1.0478E-02 9.0836E-04 -5.4124E-04 1.9335E-04 -3.5731E-05 3.6399E-06 -3.2985E-07 S8 -1.1453E-02 1.6472E-03 2.1273E-04 -1.3512E-03 1.2892E-03 -6.9689E-04 2.4530E-04 S9 -1.3858E-02 5.6990E-03 -1.9466E-03 4.8903E-04 -9.0828E-05 1.2026E-05 -1.0703E-06 S10 -3.4649E-02 1.0445E-02 -2.6004E-03 4.6882E-04 -4.7033E-05 -8.2344E-07 1.0242E-06 S11 -1.7626E-02 3.1493E-03 -6.5621E-04 9.9856E-05 -1.2467E-05 1.3113E-06 -1.1320E-07 S12 4.5865E-03 -1.9232E-03 3.4215E-04 -5.5444E-05 6.5729E-06 -5.0155E-07 1.9930E-08 S13 -2.2789E-02 2.9528E-03 -3.1429E-04 2.8890E-05 -1.9333E-06 8.4048E-08 -1.9558E-09 S14 -2.3691E-02 3.6738E-03 -5.0233E-04 5.3894E-05 -4.3658E-06 2.6314E-07 -1.1782E-08 Face number A18 A20 A22 A24 A26 A28 A30 S1 -1.7572E-10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -9.3799E-10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -2.2227E-07 8.4972E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 2.7936E-06 -9.8924E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 2.9868E-06 -1.1215E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 4.9757E-06 -2.5662E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 7.3776E-08 -6.3444E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 -5.8083E-05 9.1993E-06 -9.3579E-07 5.5345E-08 -1.4482E-09 0.0000E+00 0.0000E+00 S9 6.1369E-08 -2.3858E-09 8.7548E-11 -3.4633E-12 7.3236E-14 0.0000E+00 0.0000E+00 S10 -1.5502E-07 1.2313E-08 -5.6493E-10 1.4158E-11 -1.5046E-13 0.0000E+00 0.0000E+00 S11 7.5657E-09 -3.6417E-10 1.1635E-11 -2.1828E-13 1.8060E-15 0.0000E+00 0.0000E+00 S12 1.7682E-10 -7.0881E-11 4.1920E-12 -1.2854E-13 2.1149E-15 -1.4801E-17 0.0000E+00 S13 -5.6587E-12 2.1381E-12 -7.9418E-14 1.6118E-15 -1.9757E-17 1.3802E-19 -4.2499E-22 S14 3.9246E-10 -9.6970E-12 1.7554E-13 -2.2646E-15 1.9730E-17 -1.0406E-19 2.5093E-22

[0087] Table 2

[0088] In this embodiment, the total effective focal length f of the inner focus lens system is 8.60 mm.

[0089] Table 3 shows the distance U of the inner focus lens system from the object, the air interval D1 between the first lens group and the second lens group on the optical axis, and the air interval D2 between the second lens group and the third lens group on the optical axis of Example 1, wherein the units of U, D1, and D2 are all millimeters (mm). When U is infinite, the inner focus lens system is in a telephoto state; when U is 150 mm, the inner focus lens system is in a close-up state.

[0090]

[0091]

[0092] Table 3

[0093] Example 2

[0094] The following reference Figure 2 and Figure 4 An inner focus lens system according to Example 2 of the present application is described.

[0095] like Figure 2 and Figure 4 As shown, the inner focusing lens system includes a barrel assembly and an optical lens group. The barrel assembly includes a first barrel P01, a second barrel P02 and a third barrel P03 arranged in sequence from the object side to the image plane along the optical axis. The structure of the optical lens group is the same as that of the optical lens group of Example 1. The inner focusing lens system also includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second barrel P02.

[0096] The structure of the optical lens group of this embodiment is the same as that of the optical lens group of embodiment 1, that is, the basic parameter table of the inner focus lens system of this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and embodiment 1 is that the structural dimensions of the first lens barrel P01, the second lens barrel P02, the third lens barrel P03, the second spacer P2, the third spacer P3, the fourth spacer P4 and the fifth spacer P5 are different. For example, the parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45 and CP5 are different.

[0097] Example 3

[0098] The following reference Figure 2 and Figure 5 An inner focus lens system according to Example 3 of the present application is described.

[0099] like Figure 2 and Figure 5 As shown, the inner focusing lens system includes a barrel assembly and an optical lens group. The barrel assembly includes a first barrel P01, a second barrel P02 and a third barrel P03 arranged in sequence from the object side to the image plane along the optical axis. The structure of the optical lens group is the same as that of the optical lens group of Example 1. The inner focusing lens system also includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second barrel P02.

[0100] The structure of the optical lens group of this embodiment is the same as that of the optical lens group of embodiment 1, that is, the basic parameter table of the inner focus lens system of this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and embodiment 1 is that the structural dimensions of the first lens barrel P01, the second lens barrel P02, the third lens barrel P03, the second spacer P2, the third spacer P3, the fourth spacer P4 and the fifth spacer P5 are different. For example, the parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45 and CP5 are different.

[0101] Fig. 6A The axial chromatic aberration curve of the inner focusing lens system of Example 1, 2 or 3 in the telephoto state is shown, which indicates the deviation of the focal point of light rays of different wavelengths after passing through the inner focusing lens system. Figure 6B The astigmatism curve of the inner focus lens system of Example 1, 2 or 3 in the telephoto state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 6C The distortion curve of the inner focus lens system of Embodiment 1, 2 or 3 in the telephoto state is shown, which indicates the distortion magnitude values ​​corresponding to different image heights. FIG. 6A to FIG. 6C It can be seen that the inner focus lens system of Example 1, 2 or 3 can achieve good imaging quality in the telephoto state.

[0102] Fig. 7A The axial chromatic aberration curve of the inner focus lens system of Example 1, 2 or 3 in the close-up state is shown, which indicates the deviation of the focal point of light rays of different wavelengths after passing through the inner focus lens system. Figure 7B The astigmatism curve of the inner focus lens system of Example 1, 2 or 3 in the close-up state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 7C The distortion curve of the close-up state of the inner focus lens system of Embodiment 1, 2 or 3 is shown, which indicates the distortion magnitude values ​​corresponding to different image heights. 7A to 7C It can be seen that the inner focus lens system of Embodiment 1, 2 or 3 can achieve good imaging quality in the close-up state.

[0103] Example 4

[0104] The following reference Figure 8 and Fig. 9 An inner focus lens system according to Example 4 of the present application is described.

[0105] like Figure 8 and Fig. 9 As shown, the inner focus lens system includes a lens barrel assembly and an optical lens group. The lens barrel assembly includes a first lens barrel P01, a second lens barrel P02 and a third lens barrel P03 arranged in sequence from the object side to the image plane along the optical axis.

[0106] The optical lens group includes a first lens group G1 placed in the first lens barrel P01, a second lens group G2 placed in the second lens barrel P02 and having positive focal power, and a third lens group G3 placed in the third lens barrel P03 and having negative focal power in order from the object side to the image plane along the optical axis. The first lens group G1 and the third lens group G3 are fixed relative to the image plane on the optical axis. The second lens group G2 can move relative to the first lens group G1 along the optical axis. When the inner focusing lens system is from far to near at the distance of the object, adjusting the distance between the second lens group G2 and the first lens group G1 on the optical axis can switch the inner focusing lens system between the telephoto state and the close-up state, thereby realizing the focus adjustment of the inner focusing lens system. In the example, the first lens group G1 includes a first lens E1. The second lens group G2 includes a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image plane along the optical axis. The third lens group G3 includes a seventh lens E7. The second lens group G2 further includes a stop STO, which is disposed between the object side and the second lens E2.

[0107] The first lens E1 has negative focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive focal power, and its object side surface S3 is convex, and its image side surface S4 is convex. The third lens E3 has negative focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has negative focal power, and its object side surface S9 is concave, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has negative focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. A filter E8 is also arranged between the seventh lens E7 and the image surface S17, and the filter E8 has an object side surface S15 and an image side surface S16. Light from the object passes through the surfaces S1 to S16 in sequence and is finally imaged on the image plane S17.

[0108] The inner focus lens system includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second lens barrel P02. The spacers can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the second lens barrel P02 better supported, thereby enhancing the structural stability of the inner focus lens system.

[0109] Table 4 shows the basic parameters of the inner focus lens system of Example 4, wherein the units of the curvature radius, thickness / distance, and focal length are all millimeters (mm).

[0110]

[0111] Table 4

[0112] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the seventh lens E7 are both aspherical surfaces. Table 5 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A5 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0113] Face number A4 A6 A8 A10 A12 A14 A16 S1 -5.8922E-03 2.3970E-04 -4.4019E-04 2.2722E-04 -6.7964E-05 1.2615E-05 -1.4156E-06 S2 -6.0541E-03 3.8568E-04 -8.8120E-04 5.6244E-04 -2.0654E-04 4.6763E-05 -6.3821E-06 S3 1.9001E-03 6.1939E-04 -9.9361E-04 8.4352E-04 -4.2052E-04 1.3045E-04 -2.4517E-05 S4 -3.3539E-03 1.2514E-02 -1.3471E-02 9.0643E-03 -4.0305E-03 1.1815E-03 -2.1900E-04 S5 -1.6049E-02 1.6525E-02 -1.5654E-02 1.1098E-02 -5.7390E-03 2.1556E-03 -5.7158E-04 S6 -1.3165E-02 5.5886E-03 -7.1147E-04 -1.8799E-03 2.2360E-03 -1.3153E-03 4.7202E-04 S7 -8.6909E-03 2.0361E-03 -6.4750E-04 -1.6727E-03 2.0942E-03 -1.2258E-03 4.2254E-04 S8 -2.2343E-02 2.2742E-02 -2.6490E-02 2.3415E-02 -1.5181E-02 7.0715E-03 -2.3461E-03 S9 -4.2719E-02 2.6282E-02 -1.7137E-02 9.2917E-03 -3.7211E-03 1.0496E-03 -2.0324E-04 S10 -4.7631E-02 1.3376E-02 -1.7192E-03 -1.4894E-03 1.2906E-03 -5.2426E-04 1.3171E-04 S11 -1.7619E-02 3.2567E-03 -1.1796E-03 4.4763E-04 -1.4339E-04 3.4087E-05 -5.8387E-06 S12 6.1199E-03 -1.7154E-03 -1.4434E-04 1.8784E-04 -6.3504E-05 1.3090E-05 -1.8488E-06 S13 -3.4652E-02 6.3016E-03 -9.5375E-04 1.2408E-04 -1.2396E-05 9.2830E-07 -5.2778E-08 S14 -3.7797E-02 7.9936E-03 -1.4977E-03 2.1841E-04 -2.3926E-05 1.9508E-06 -1.1829E-07 Face number A18 A20 A22 A24 A26 A28 A30 S1 8.7692E-08 -2.2984E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 4.8000E-07 -1.5257E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 2.5479E-06 -1.1060E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 2.3227E-05 -1.0711E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 1.0080E-04 -1.0518E-05 4.8723E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 -1.0434E-04 1.3103E-05 -7.1702E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 -8.7951E-05 1.0293E-05 -5.2136E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 5.4820E-04 -8.7993E-05 9.2201E-06 -5.6691E-07 1.5483E-08 0.0000E+00 0.0000E+00 S9 2.7494E-05 -2.8101E-06 2.3607E-07 -1.4727E-08 4.5534E-10 0.0000E+00 0.0000E+00 S10 -2.1433E-05 2.2486E-06 -1.4624E-07 5.3434E-09 -8.3485E-11 0.0000E+00 0.0000E+00 S11 7.1672E-07 -6.2735E-08 3.8634E-09 -1.6271E-10 4.4398E-12 -7.0399E-14 4.9009E-16 S12 1.8547E-07 -1.3341E-08 6.8303E-10 -2.4280E-11 5.6909E-13 -7.9014E-15 4.9178E-17 S13 2.3022E-09 -7.6764E-11 1.9180E-12 -3.4602E-14 4.2350E-16 -3.1341E-18 1.0554E-20 S14 5.3252E-09 -1.7663E-10 4.2459E-12 -7.1750E-14 8.0653E-16 -5.4058E-18 1.6327E-20

[0114] Table 5

[0115] In this embodiment, the total effective focal length f of the inner focus lens system is 7.67 mm.

[0116] Table 6 shows the distance U of the inner focus lens system from the object, the air interval D1 between the first lens group and the second lens group on the optical axis, and the air interval D2 between the second lens group and the third lens group on the optical axis of Example 4, wherein the units of U, D1, and D2 are all millimeters (mm). When U is infinite, the inner focus lens system is in a telephoto state; when U is 150 mm, the inner focus lens system is in a close-up state.

[0117] Object distance U Infinity 150 D1 0.9600 0.6788 D2 1.6840 1.9652

[0118] Table 6

[0119] Example 5

[0120] The following reference Figure 8 and Fig.10 An inner focus lens system according to Example 5 of the present application is described.

[0121] like Figure 8 and Fig.10 As shown, the inner focusing lens system includes a barrel assembly and an optical lens group. The barrel assembly includes a first barrel P01, a second barrel P02 and a third barrel P03 arranged in sequence from the object side to the image plane along the optical axis. The structure of the optical lens group is the same as that of the optical lens group of Example 4. The inner focusing lens system also includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second barrel P02.

[0122] The structure of the optical lens group of this embodiment is the same as that of the optical lens group of embodiment 4, that is, the basic parameter table of the inner focus lens system of this embodiment is the same as that of table 4, and the aspheric coefficient table is the same as that of table 5. The difference between this embodiment and embodiment 4 is that the structural dimensions of the first lens barrel P01, the second lens barrel P02, the third lens barrel P03, the second spacer P2, the third spacer P3, the fourth spacer P4 and the fifth spacer P5 are different. For example, the parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45 and CP5 are different.

[0123] Example 6

[0124] The following reference Figure 8 and Fig.11 An inner focus lens system according to Example 6 of the present application is described.

[0125] like Figure 8 and Fig.11 As shown, the inner focusing lens system includes a barrel assembly and an optical lens group. The barrel assembly includes a first barrel P01, a second barrel P02 and a third barrel P03 arranged in sequence from the object side to the image plane along the optical axis. The structure of the optical lens group is the same as that of the optical lens group of Example 4. The inner focusing lens system also includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second barrel P02.

[0126] The structure of the optical lens group of this embodiment is the same as that of the optical lens group of embodiment 4, that is, the basic parameter table of the inner focus lens system of this embodiment is the same as that of table 4, and the aspheric coefficient table is the same as that of table 5. The difference between this embodiment and embodiment 4 is that the structural dimensions of the first lens barrel P01, the second lens barrel P02, the third lens barrel P03, the second spacer P2, the third spacer P3, the fourth spacer P4 and the fifth spacer P5 are different. For example, the parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45 and CP5 are different.

[0127] Fig. 12A The axial chromatic aberration curve of the inner focusing lens system of Example 4, 5 or 6 in the telephoto state is shown, which indicates the deviation of the focal point of light rays of different wavelengths after passing through the inner focusing lens system. Fig. 12B The astigmatism curve of the inner focus lens system of Example 4, 5 or 6 in the telephoto state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Fig. 12CThe distortion curve of the inner focus lens system of Embodiment 4, 5 or 6 in the telephoto state is shown, which indicates the distortion magnitude values ​​corresponding to different image heights. FIG. 12A to FIG. 12C It can be seen that the internal focus lens system of Example 4, 5 or 6 can achieve good imaging quality in the telephoto state.

[0128] Fig.13A The axial chromatic aberration curve of the inner focus lens system of Example 4, 5 or 6 in the close-up state is shown, which indicates the deviation of the focal point of light rays of different wavelengths after passing through the inner focus lens system. Fig. 13B The astigmatism curve of the inner focus lens system of Example 4, 5 or 6 in the close-up state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Fig. 13C The distortion curve of the close-up state of the inner focus lens system of Embodiment 4, 5 or 6 is shown, which indicates the distortion magnitude values ​​corresponding to different image heights. FIG. 13A to FIG. 13C It can be seen that the inner focus lens system of Example 4, 5 or 6 can achieve good imaging quality in the close-up state.

[0129] Example 7

[0130] The following reference Fig.14 and Fig.15 An inner focus lens system according to Example 7 of the present application is described.

[0131] like Fig.14 and Fig.15 As shown, the inner focus lens system includes a lens barrel assembly and an optical lens group. The lens barrel assembly includes a first lens barrel P01, a second lens barrel P02 and a third lens barrel P03 arranged in sequence from the object side to the image plane along the optical axis.

[0132] The optical lens group includes a first lens group G1 placed in the first lens barrel P01, a second lens group G2 placed in the second lens barrel P02 and having positive focal power, and a third lens group G3 placed in the third lens barrel P03 and having negative focal power in order from the object side to the image plane along the optical axis. The first lens group G1 and the third lens group G3 are fixed relative to the image plane on the optical axis. The second lens group G2 can move relative to the first lens group G1 along the optical axis. When the inner focusing lens system is from far to near at the distance of the object, adjusting the distance between the second lens group G2 and the first lens group G1 on the optical axis can switch the inner focusing lens system between the telephoto state and the close-up state, thereby realizing the focus adjustment of the inner focusing lens system. In the example, the first lens group G1 includes a first lens E1. The second lens group G2 includes a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6 in order from the object side to the image plane along the optical axis. The third lens group G3 includes a seventh lens E7. The second lens group G2 further includes a stop STO, which is disposed between the object side and the second lens E2.

[0133] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has positive focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has negative focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has negative focal power, and its object side surface S13 is concave, and its image side surface S14 is concave. A filter E8 is also arranged between the seventh lens E7 and the image surface S17, and the filter E8 has an object side surface S15 and an image side surface S16. Light from the object passes through the surfaces S1 to S16 in sequence and is finally imaged on the image plane S17.

[0134] The inner focus lens system includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second lens barrel P02. The spacers can block the excess light in the imaging process from entering the next lens, and at the same time make the lens and the second lens barrel P02 better supported, thereby enhancing the structural stability of the inner focus lens system.

[0135] Table 7 shows the basic parameter table of the inner focus lens system of Example 7, wherein the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0136]

[0137] Table 7

[0138] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the seventh lens E7 are both aspherical surfaces. Table 8 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A5 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0139]

[0140]

[0141] Table 8

[0142] In this embodiment, the total effective focal length f of the inner focus lens system is 8.35 mm.

[0143] Table 9 shows the distance U of the inner focus lens system at the object distance, the air interval D1 between the first lens group and the second lens group on the optical axis, and the air interval D2 between the second lens group and the third lens group on the optical axis of Example 7, wherein the units of U, D1, and D2 are all millimeters (mm). When U is infinite, the inner focus lens system is in a telephoto state; when U is 150 mm, the inner focus lens system is in a close-up state.

[0144] Object distance U Infinity 150 D1 0.9464 0.6276 D2 1.8073 2.1261

[0145] Table 9

[0146] Example 8

[0147] The following reference Fig.14 and Fig.16 An inner focus lens system according to Example 8 of the present application is described.

[0148] like Fig.14 and Fig.16 As shown, the inner focusing lens system includes a barrel assembly and an optical lens group. The barrel assembly includes a first barrel P01, a second barrel P02 and a third barrel P03 arranged in sequence from the object side to the image plane along the optical axis. The structure of the optical lens group is the same as that of the optical lens group of Example 7. The inner focusing lens system also includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second barrel P02.

[0149] The structure of the optical lens group of this embodiment is the same as that of the optical lens group of embodiment 7, that is, the basic parameter table of the inner focus lens system of this embodiment is the same as that of table 7, and the aspheric coefficient table is the same as that of table 8. The difference between this embodiment and embodiment 7 is that the structural dimensions of the first lens barrel P01, the second lens barrel P02, the third lens barrel P03, the second spacer P2, the third spacer P3, the fourth spacer P4 and the fifth spacer P5 are different. For example, the parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45 and CP5 are different.

[0150] Example 9

[0151] The following reference Fig.14 and Fig.17 An inner focus lens system according to Example 9 of the present application is described.

[0152] like Fig.14 and Fig.17 As shown, the inner focusing lens system includes a barrel assembly and an optical lens group. The barrel assembly includes a first barrel P01, a second barrel P02 and a third barrel P03 arranged in sequence from the object side to the image plane along the optical axis. The structure of the optical lens group is the same as that of the optical lens group of Example 7. The inner focusing lens system also includes a second spacer P2, a third spacer P3, a fourth spacer P4 and a fifth spacer P5 placed in the second barrel P02.

[0153] The structure of the optical lens group of this embodiment is the same as that of the optical lens group of embodiment 7, that is, the basic parameter table of the inner focus lens system of this embodiment is the same as that of table 7, and the aspheric coefficient table is the same as that of table 8. The difference between this embodiment and embodiment 7 is that the structural dimensions of the first lens barrel P01, the second lens barrel P02, the third lens barrel P03, the second spacer P2, the third spacer P3, the fourth spacer P4 and the fifth spacer P5 are different. For example, the parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45 and CP5 are different.

[0154] Fig.18A The axial chromatic aberration curve of the inner focusing lens system of Example 7, 8 or 9 in the telephoto state is shown, which indicates the deviation of the focal point of light rays of different wavelengths after passing through the inner focusing lens system. Fig.18B The astigmatism curve of the inner focus lens system of Example 7, 8 or 9 in the telephoto state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Fig.18C The distortion curve of the telephoto state of the inner focus lens system of Embodiment 7, 8 or 9 is shown, which indicates the distortion magnitude values ​​corresponding to different image heights. 18A to 18C It can be seen that the internal focus lens system of Example 7, 8 or 9 can achieve good imaging quality in the telephoto state.

[0155] Fig.19A The axial chromatic aberration curve of the inner focusing lens system of Example 7, 8 or 9 in the close-up state is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the inner focusing lens system. Fig.19B The astigmatism curve of the inner focus lens system of Example 7, 8 or 9 in the close-up state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Fig.19C The distortion curve of the close-up state of the inner focus lens system of Embodiment 7, 8 or 9 is shown, which indicates the distortion magnitude values ​​corresponding to different image heights. FIG. 19A to FIG. 19C It can be seen that the inner focus lens system of Example 7, 8 or 9 can achieve good imaging quality in the close-up state.

[0156] Table 10 shows the values ​​of parameters such as L1, L2, L3, d01s, d01m, D01m, d02s, d03s, D03s, D03m, ΔEP0, EP022, EP23, EP34, EP45, CP5, F2 and EPD in each embodiment of Examples 1-9. Among them, some of the above parameters can be calculated according to Figure 1 The units of the parameters listed in Table 10 are all mm.

[0157]

[0158]

[0159] Table 10

[0160] Table 11 shows the values ​​of the conditional expressions of each of Examples 1 to 9.

[0161] Conditional / Example 1 2 3 4 5 6 7 8 9 (F2+|F3|) / |F1| 0.16 0.16 0.16 0.09 0.09 0.09 0.06 0.06 0.06 F2 / L2 1.33 1.33 1.33 1.36 1.36 1.36 1.45 1.45 1.45 |F3| / L3 2.09 2.09 2.09 1.89 1.89 1.89 1.75 1.75 1.75 EPD / (d01m-d02s) 2.09 2.09 2.09 1.73 1.73 1.73 1.98 1.98 1.98 (D01m-d01s) / L1 1.25 1.25 1.25 1.16 1.16 1.16 1.27 1.27 1.27 L3 / (D03m-d03s) 1.17 1.17 1.17 1.27 1.27 1.27 1.19 1.19 1.19 f2 / (EP022-T23) 6.74 6.90 6.35 6.06 6.30 6.00 7.51 7.94 7.47 EP23 / (T34×(N3-1)) 1.16 1.24 1.29 1.32 1.33 1.33 1.11 1.23 1.22 (EP34-T45) / CT4 0.11 0.26 0.66 0.73 0.78 0.67 1.40 1.42 1.29 (EP45+CP5) / T56 3.20 2.81 2.24 2.00 1.94 1.81 1.71 1.57 1.51 F3 / (D03s-d03s) -2.41 -2.41 -2.41 -2.35 -2.35 -2.35 -2.06 -2.06 -2.06 F3 / (L3-CT7) -2.82 -2.82 -2.82 -2.54 -2.54 -2.54 -2.43 -2.43 -2.43 (F2+|F3|) / ΔEP0 38.31 38.31 38.31 44.37 44.37 44.37 42.67 42.67 42.67 ∑AT / ΔEP0 7.07 7.07 7.07 7.86 7.86 7.86 7.47 7.47 7.47

[0162] Table 11

[0163] The present application also provides an imaging device, whose electronic photosensitive element can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in a mobile electronic device such as a mobile phone. The imaging device is equipped with the internal focus lens system described above.

[0164] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other.

Claims

1. An inner focusing lens system, characterized in that: The invention comprises a lens barrel assembly and an optical lens group, wherein the lens barrel assembly comprises a first lens barrel, a second lens barrel and a third lens barrel which are arranged in sequence from the object side to the image plane along the optical axis; wherein, The optical lens group includes, in sequence from the object side to the image plane along the optical axis: A first lens group disposed in the first lens barrel includes a first lens having optical power; a second lens group disposed in the second lens barrel and having positive power, comprising a second lens having positive power, a third lens having negative power, a fourth lens having negative power, a fifth lens having power, and a sixth lens having positive power; and A third lens group disposed in the third lens barrel includes a seventh lens having negative optical power; The positions of the first lens group and the third lens group on the optical axis relative to the image plane are fixed, and the distance of the second lens group on the optical axis relative to the first lens group is adjustable; The inner focus lens system satisfies: 0<(F2+|F3|) / |F1|<0.2, 1.3≤F2 / L2≤1.5, 1.5<|F3| / L3≤2.2, Among them, F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, F3 is the effective focal length of the third lens group, L2 is the length of the second lens barrel along the direction of the optical axis, and L3 is the length of the third lens barrel along the direction of the optical axis.

2. The inner focus lens system according to claim 1, characterized in that: The entrance pupil diameter EPD of the inner focusing lens system, the inner diameter d01m of the image side end surface of the first lens barrel and the inner diameter d02s of the object side end surface of the second lens barrel satisfy: 1.5 <EPD / (d01m-d02s)≤2.1。 3. The inner focus lens system according to claim 1, characterized in that: An outer diameter D01m of the image side end surface of the first lens barrel, an inner diameter d01s of the object side end surface of the first lens barrel, and a length L1 of the first lens barrel along the direction of the optical axis satisfy: 1.0≤(D01m-d01s) / L1≤1.

3.

4. The inner focus lens system according to claim 1, characterized in that: The outer diameter D03m of the image side end surface of the third lens barrel, the inner diameter d03s of the object side end surface of the third lens barrel and the length L3 of the third lens barrel along the direction of the optical axis satisfy: 1.0≤L3 / (D03m-d03s)≤1.

3.

5. The inner focus lens system according to claim 1, characterized in that: The effective focal length F3 of the third lens group, the outer diameter D03s of the object side end surface of the third lens barrel and the inner diameter d03s of the object side end surface of the third lens barrel satisfy: -2.5 <F3 / (D03s-d03s)≤-2.0。 6. The inner focus lens system according to claim 1, wherein: The effective focal length F3 of the third lens group, the length L3 of the third lens barrel along the direction of the optical axis and the center thickness CT7 of the seventh lens on the optical axis satisfy: -3.0 <F3 / (L3-CT7)<-2.3。 7. The inner focus lens system according to claim 1, wherein: The effective focal length F2 of the second lens group, the effective focal length F3 of the third lens group and the maximum movable distance ΔEP0 of the second lens barrel along the optical axis direction satisfy: 38<(F2+|F3|) / ΔEP0<45.

8. The inner focus lens system according to claim 1, wherein: The sum ΣT13 of the air interval between the first lens and the second lens on the optical axis and the air interval between the sixth lens and the seventh lens on the optical axis and the maximum movable distance ΔEP0 of the second lens barrel along the optical axis satisfy: 7≤ΣT13 / ΔEP0<8.

0.

9. The inner focus lens system according to any one of claims 1 to 8, characterized in that: The inner focus lens system further includes a second spacer disposed on the image side surface of the second lens and in contact with the image side surface of the second lens. The effective focal length f2 of the second lens, the air interval T23 between the second lens and the third lens on the optical axis, and the interval EP022 between the object side end surface of the second lens barrel and the second spacer along the optical axis satisfy: 5.5 <f2 / (EP022-T23)≤8.0。 10. The inner focus lens system according to any one of claims 1 to 8, characterized in that: The inner focus lens system further includes a second spacer disposed on the image side surface of the second lens and in contact with the image side surface of the second lens, and a third spacer disposed on the image side surface of the third lens and in contact with the image side surface of the third lens. The interval EP23 between the second spacer and the third spacer along the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis and the refractive index N3 of the third lens satisfy: 1.0 <EP23 / (T34×(N3-1))<1.5。 11. The inner focus lens system according to any one of claims 1 to 8, characterized in that: The inner focus lens system further includes a third spacer disposed on the image side surface of the third lens and in contact with the image side surface of the third lens, and a fourth spacer disposed on the image side surface of the fourth lens and in contact with the image side surface of the fourth lens. Among them, the interval EP34 between the third spacer and the fourth spacer along the optical axis, the air interval T45 between the fourth lens and the fifth lens on the optical axis and the center thickness CT4 of the fourth lens on the optical axis satisfy: 0.1≤(EP34-T45) / CT4<1.

5.

12. The inner focus lens system according to any one of claims 1 to 8, characterized in that: The inner focus lens system further includes a fourth spacer disposed on the image side surface of the fourth lens and in contact with the image side surface of the fourth lens, and a fifth spacer disposed on the image side surface of the fifth lens and in contact with the image side surface of the fifth lens. The interval EP45 between the fourth spacer and the fifth spacer along the optical axis, the maximum thickness CP5 of the fifth spacer, and the air interval T56 between the fifth lens and the sixth lens on the optical axis satisfy: 1.5≤(EP45+CP5) / T56<3.5.

Images