Focusing lens set

Abstract

The present application provides a focusing lens group, comprising three lens barrels, the second lens barrel being movably arranged between the first lens barrel and the third lens barrel, the first lens barrel containing a first lens, the second lens barrel containing second to fifth lenses, and the third lens barrel containing a sixth lens and a seventh lens, the optical powers of the lens groups in the three lens barrels being distributed according to "positive-positive-negative", the optical powers of the seven lenses being distributed according to "positive-positive-negative-positive-positive-negative-negative", and spacer elements being sequentially arranged on the image side surfaces of each of the second to fourth lenses and the sixth lens, and the focusing lens group further satisfying the following conditions: 4.95<(F1+F2+F3) / |Δf|<5.85; 2.35<(DT2s+DT2m) / Td2≤3.30. By virtue of the limitations of these conditional expressions, the focusing lens group can balance focusing range and imaging quality, and can also achieve miniaturization of the focusing lens group while ensuring the imaging quality of the focusing lens group.

Description

Technical Field

[0001] The present application relates to the technical field of optical devices, and in particular to a focusing lens assembly. Background Art

[0002] In recent years, with the rapid development of smartphones, mobile photography has become popular among a wide range of users. Users are no longer satisfied with simple recording of mobile photography, and are beginning to pursue higher imaging effects, including higher picture clarity, richer details, and faster and more accurate focusing capabilities. This has made optical zoom technology increasingly important. Because optical zoom lens systems require the configuration of multiple lens groups, the overall length of such systems is relatively long, so they are mainly used in periscope telephoto camera modules. The number of groups in current optical zoom systems has evolved from a simple two-lens group to a three-lens group, and the corresponding zoom method has also evolved from the external focus of the two-lens group to the internal focus of the three-lens group, as well as continuous zoom technology in which two lens groups in the three-lens group work together to focus.

[0003] Compared with external focus and continuous zoom lens systems, the length of the entire lens system of the internal focus lens system does not change, avoiding the problem of external focus and continuous zoom lens systems sucking in dust and impurities during the extension and retraction process. At the same time, it has higher imaging quality than the traditional dual-lens external focus system, and has a shorter space occupancy than the three-lens continuous zoom system, a simpler and more stable module zoom structure, and a faster focusing speed. This makes the internal focus lens system more popular with high-end flagship mobile phones. As the market pursues higher pixels and larger imaging sizes for mobile phone lenses, while also taking into account the smallest possible module height, higher requirements are placed on the design of the focusing lens group and the processability and manufacturability of the overall internal focus lens system. Summary of the Invention

[0004] One advantage of the present application is that it provides a focusing lens assembly that can solve the problem of difficulty in controlling image clarity and distortion when the lens changes too drastically during the focusing process.

[0005] In one aspect, the present application provides a focusing lens assembly, comprising a first lens barrel, a second lens barrel, and a third lens barrel arranged in sequence along the same optical axis, wherein the second lens barrel is movably disposed between the first lens barrel and the third lens barrel;

[0006] a first lens group mounted on the first lens barrel, the first lens group including a first lens with positive optical power;

[0007] a second lens group mounted on the second lens barrel, the second lens group having positive refractive power, the second lens group comprising a second lens having positive refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens having positive refractive power;

[0008] The third lens group is installed in the third lens barrel. The third lens group has a negative optical power. The third lens group includes a sixth lens with a negative optical power and a seventh lens with a negative optical power;

[0009] At least one spacer element is included between any two adjacent lenses in the second lens group, and the object side surface of the spacer element contacts the adjacent lens;

[0010] The focusing lens group satisfies: 4.95 < (F1 + F2 + F3) / |Δf| < 5.85; and 2.35 ≤ (DT2s + DT2m) / Td2 ≤ 3.30;

[0011] Where, 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; △f is the difference in the effective focal length of the focusing lens group when the second lens barrel moves from the position closest to the first lens barrel to the position closest to the third lens barrel; DT2s is the clear aperture diameter on the object side of the second lens barrel, DT2m is the clear aperture diameter on the image side of the second lens barrel; Td2 is the distance on the optical axis from the object side surface of the second lens in the second lens group to the image side surface of the fifth lens.

[0012] In some embodiments of the present application, the second lens barrel satisfies: 0.80 ≤ DT2s / DT2m < 1.40;

[0013] Where, DT2s is the clear aperture diameter on the object side of the second lens barrel, DT2m is the clear aperture diameter on the image side of the second lens barrel.

[0014] In some embodiments of the present application, the focusing lens group satisfies: 2.10 < F2 / L2 ≤ 2.95; and 2.10 ≤ F2 / Td2 ≤ 2.85;

[0015] Where, F2 is the effective focal length of the second lens group, L2 is the maximum height of the second lens barrel, Td2 is the distance on the optical axis from the object side surface of the second lens in the second lens group to the image side surface of the fifth lens.

[0016] In some embodiments of the present application, a second spacer element that contacts the image side surface of the second lens is provided on the image side of the second lens. The focusing lens group further satisfies: 1.65 ≤ f2 / d2s < 5.20;

[0017] Where, f2 is the effective focal length of the second lens, d2s is the inner diameter of the object side surface of the second spacer element.

[0018] In some embodiments of the present application, a third spacer element in contact with the image side surface of the third lens is provided on the image side of the third lens, and the focusing lens group further satisfies: 0.50 < (f3 + f4) / d3s < 2.15;

[0019] Where f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, and d3s is the inner diameter of the object side surface of the third spacer element.

[0020] In some embodiments of the present application, a fourth spacer element in contact with the image side surface of the fourth lens is provided on the image side of the fourth lens, and the focusing lens group further satisfies: 2.15 < f4 / d4m < 3.45;

[0021] Where f4 is the effective focal length of the fourth lens, and d4m is the inner diameter of the image side surface of the fourth spacer element.

[0022] In some embodiments of the present application, the focusing lens group further satisfies: 4.95 ≤ DT2m / (CT5 × N5) < 11.95;

[0023] Where DT2m is the clear aperture diameter on the image side of the second lens barrel, CT5 is the central thickness of the fifth lens, and N5 is the refractive index of the fifth lens.

[0024] In some embodiments of the present application, the focusing lens group further satisfies: 3.35 < DT2s / (CT2 × N2) < 6.45;

[0025] Where DT2s is the clear aperture diameter on the object side of the second lens barrel, CT2 is the central thickness of the second lens, and N2 is the refractive index of the second lens.

[0026] In some embodiments of the present application, the focusing lens group satisfies: -3.50 < F3 / L3 ≤ -2.55; and 0.80 ≤ Td3 / L3 < 0.95;

[0027] Where L3 is the maximum height of the third lens barrel along the optical axis direction, F3 is the effective focal length of the third lens group, and Td3 is the distance on the optical axis from the object side surface of the sixth lens to the image side surface of the seventh lens in the third lens group.

[0028] In some embodiments of the present application, the focusing lens group further satisfies: 3.65 < |F3| / (L3 - T67) ≤ 5.10;

[0029] Where F3 is the effective focal length of the third lens group, L3 is the maximum height of the third lens barrel along the optical axis direction, and T67 is the air gap between the sixth lens and the seventh lens on the optical axis.

[0030] In some embodiments of the present application, the focusing lens group further satisfies: 0.40 < ET6 / (CT6 + T67) ≤ 0.95;

[0031] Where, ET6 is the maximum thickness of the non-transmissive region of the sixth lens, CT6 is the central thickness of the sixth lens, and T67 is the air gap between the sixth lens and the seventh lens on the optical axis.

[0032] In some embodiments of the present application, the focusing lens group further satisfies: 0.35 < ET7 / (T67 + CT7) < 1.10;

[0033] Where, ET7 is the maximum thickness of the non-transmissive region of the seventh lens, CT7 is the central thickness of the seventh lens, and T67 is the air gap between the sixth lens and the seventh lens on the optical axis.

[0034] In some embodiments of the present application, the focusing lens group satisfies: 1.45 < F1 / F2 < 2.45; and -3.60 < F1 / F3 ≤ -2.10;

[0035] Where, F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, and F3 is the effective focal length of the third lens group.

[0036] In some embodiments of the present application, the focusing lens group further satisfies: 1.70 ≤ (T12 + T56) / ΔEP0 < 2.20;

[0037] Where, T12 is the air gap between the first lens and the second lens on the optical axis, T56 is the air gap between the fifth lens and the sixth lens on the optical axis, and ΔEP0 is the maximum distance that the second lens barrel can move along the optical axis.

[0038] In some embodiments of the present application, the focusing lens group further satisfies: 4.40 < (L1 + L2 + L3) / ΔEP0 < 5.55;

[0039] Where, L1 is the maximum height of the first lens barrel along the optical axis, L2 is the maximum height of the second lens barrel along the optical axis, L3 is the maximum height of the third lens barrel along the optical axis, and ΔEP0 is the maximum distance that the second lens barrel can move along the optical axis.

[0040] In summary, the focusing lens group of the present application adopts a three-barrel combination structure, and the first to third lens groups are sequentially built in the first to third lens barrels, wherein the first lens group includes the first lens, the second lens group includes the second to fifth lenses, and the third lens group includes the sixth and seventh lenses. By distributing the optical focal lengths of the three lens groups in sequence according to "positive-positive-negative" and distributing the optical focal lengths of the first to seventh lenses in sequence according to "positive-positive-negative-positive-positive-negative-negative" and further movably arranging the second lens barrel between the first and third lens barrels along the optical axis, the focusing lens group can take into account the imaging performance of different focal lengths such as far focus, near focus and macro; by controlling the ratio between the sum of the focal lengths of the three lens groups and the maximum value of the effective focal length change of the focusing lens group, the focusing lens group can take into account the focusing range and imaging quality. On the one hand, constraining the lower limit of the ratio enables the focusing range of the focusing lens group to cover the requirements for different focal lengths in actual use. On the other hand, when the effective focal length of the focusing lens group changes too drastically, the image clarity, distortion, etc. are difficult to control during the focusing process. By constraining the upper limit of the ratio, the impact of the rapid change of the effective focal length of the focusing lens group during the focusing process on the imaging quality can be reduced; further, the ratio of the sum of the clear diameters on the object side and the image side of the second lens barrel in the second lens group to the distance on the optical axis from the object side of the second lens to the image side of the fifth lens is controlled to be within a reasonable range. On the one hand, an appropriate clear diameter can ensure the amount of light entering the optical system in the focusing lens group, and ensure the brightness, contrast and high performance of the imaging. On the other hand, an appropriate distance on the optical axis from the object side of the second lens to the image side of the fifth lens will make the overall structure of the optical system compact, which is conducive to the miniaturization of the focusing lens group. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic structural diagram of a focusing lens assembly provided in this application;

[0042] Figure 2 for Figure 1 Dimensional diagram of the focusing lens assembly shown;

[0043] Figure 3A This is a schematic structural diagram of the focusing lens assembly under working condition 1-1 in Example 1 provided in this application;

[0044] Figure 3B This is a schematic structural diagram of the focusing lens assembly under working condition 1-2 in Example 1 provided in this application;

[0045] Figure 3C This is a schematic structural diagram of the focusing lens assembly under working conditions 1-3 in Example 1 provided in this application;

[0046] Figure 4Aaxial chromatic aberration curves of the focusing lens assembly under the three working conditions shown in Example 1 when the object distance is infinite;

[0047] Figure 4B Graphs showing astigmatism curves of the focusing lens assembly under the three working conditions shown in Example 1 when the object distance is infinite;

[0048] Figure 4C Graphs showing distortion of the focusing lens assembly under the three working conditions shown in Example 1 when the object distance is infinite;

[0049] Figure 5A axial chromatic aberration curves of the focusing lens assembly under the three working conditions shown in Example 1 when the object distance is 57.8556 mm;

[0050] Figure 5B Graphs showing astigmatism curves of the focusing lens assembly under the three working conditions shown in Example 1 when the object distance is 57.8556 mm;

[0051] Figure 5C Graphs showing distortion of the focusing lens assembly under the three working conditions shown in Example 1 when the object distance is 57.8556 mm;

[0052] Figure 6A This is a schematic diagram of the structure of the focusing lens assembly under working condition 2-1 in Example 2 provided in this application;

[0053] Figure 6B This is a schematic structural diagram of the focusing lens assembly under working condition 2-2 in Example 2 provided in this application;

[0054] Figure 6C This is a schematic structural diagram of the focusing lens assembly under working condition 2-3 in Example 2 provided in this application;

[0055] Figure 7A axial chromatic aberration curves of the focusing lens assembly under the three working conditions shown in Example 2 when the object distance is infinite;

[0056] Figure 7B Graphs showing astigmatism curves of the focusing lens assembly under the three working conditions shown in Example 2 when the object distance is infinite;

[0057] Figure 7C Graphs showing distortion of the focusing lens assembly at infinite object distance under the three working conditions shown in Example 2;

[0058] Figure 8A axial chromatic aberration curves of the focusing lens assembly under the three working conditions shown in Example 2 when the object distance is 52.6455 mm;

[0059] Figure 8B Graphs showing astigmatism curves of the focusing lens assembly under the three working conditions shown in Example 2 when the object distance is 52.6455 mm;

[0060] Figure 8C Graphs showing distortion of the focusing lens assembly under the three working conditions shown in Example 2 when the object distance is 52.6455 mm;

[0061] Figure 9A This is a schematic diagram of the structure of the focusing lens assembly under working condition 3-1 in Example 3 provided in this application;

[0062] Figure 9B This is a schematic diagram of the structure of the focusing lens assembly under working condition 3-2 in Example 3 provided in this application;

[0063] Figure 9C This is a schematic structural diagram of the focusing lens assembly under working condition 3-3 in Example 3 provided in this application;

[0064] Figure 10A axial chromatic aberration curves of the focusing lens assembly under the three working conditions shown in Example 3 when the object distance is infinite;

[0065] Figure 10B Graphs showing astigmatism curves of the focusing lens assembly under the three working conditions shown in Example 3 when the object distance is infinite;

[0066] Figure 10C Graphs showing distortion of the focusing lens assembly under the three working conditions shown in Example 3 when the object distance is infinite;

[0067] Figure 11A axial chromatic aberration curves of the focusing lens assembly under the three working conditions shown in Example 3 when the object distance is 66.6675 mm;

[0068] Figure 11B Graphs showing astigmatism of the focusing lens assembly under the three working conditions shown in Example 3 when the object distance is 66.6675 mm;

[0069] Figure 11C Graphs showing distortion of the focusing lens assembly under the three working conditions shown in Example 3 when the object distance is 66.6675 mm;

[0070] Figure 12 Schematic diagram of the MTF curve when the focusing lens group meets (F1+F2+F3) / |Δf|=5.58;

[0071] Figure 13 Schematic diagram of the MTF curve when the focusing lens group meets (F1+F2+F3) / |Δf|=4.35;

[0072] Figure 14 Schematic diagram of the MTF curve when the focusing lens group meets (F1+F2+F3) / |Δf|=8.22.

[0073] Reference numerals:

[0074] E1, first lens; E2, second lens; E3, third lens; E4, fourth lens; E5, fifth lens; E6, sixth lens; E7, seventh lens; P01, first lens barrel; P02, second lens barrel; P03, third lens barrel; P2, second spacer; P3, third spacer; P4, fourth spacer; P6, sixth spacer; E8, prism; E9, filter. DETAILED DESCRIPTION

[0075] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0076] It should be noted that in this specification, the terms "first," "second," "third," etc., are used merely to distinguish one feature from another, and do not constitute any limitation upon the features. Thus, the first lens E1 discussed below could also be referred to as the second lens E2 or the third lens E3 without departing from the teachings of the present application.

[0077] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0078] In this document, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it indicates that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it indicates that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined according to common methods in the art, for example, by determining whether it is concave or convex based on the positive or negative R value (R refers to the radius of curvature of the paraxial region). In this document, the surface of each lens closest to the subject is called the object-side surface, and the surface of each lens closest to the imaging plane is called the image-side surface. For the object-side surface, a positive R value indicates a convex surface, and a negative R value indicates a concave surface. For the image-side surface, a positive R value indicates a concave surface, and a negative R value indicates a convex surface.

[0079] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "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.

[0080] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0081] 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 following examples only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the patent of this application. It should be pointed out that for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all fall within the scope of protection of the present application. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0082] It is worth noting that in the present application, the non-light-transmitting area of the lens is located at the edge of the lens. This area is mainly used to contact the lens barrel or spacer element to support the lens. The edge thickness of the lens is the thickness of the non-light-transmitting area along the optical axis.

[0083] According to one aspect of this application, Figure 1 and Figure 2 As shown, Figure 1 This is a schematic structural diagram of a focusing lens assembly provided in this application. Figure 2 for Figure 1 A schematic diagram of the dimensions of a focusing lens assembly is shown. One embodiment of the present application provides a focusing lens assembly, which may include a first lens barrel, a second lens barrel, and a third lens barrel arranged in sequence along the same optical axis, wherein the second lens barrel is movably disposed between the first lens barrel and the third lens barrel;

[0084] A first lens group is mounted on the first lens barrel P01, wherein the first lens group includes a first lens E1 having positive refractive power;

[0085] a second lens group mounted on the second lens barrel P02, the second lens group having positive refractive power, comprising a second lens E2 having positive refractive power, a third lens E3 having negative refractive power, a fourth lens E4 having positive refractive power, and a fifth lens E5 having positive refractive power;

[0086] a third lens group, mounted on the third lens barrel P03, the third lens group having negative optical power, and comprising a sixth lens E6 having negative optical power and a seventh lens E7 having negative optical power;

[0087] At least one spacer element is included between any two adjacent lenses in the second lens group, and the object-side surface of the spacer element is in contact with the adjacent lenses;

[0088] The focusing lens group satisfies the following conditions: 4.95<(F1+F2+F3) / |Δf|<5.85; and 2.35≤(DT2s+DT2m) / Td2≤3.30;

[0089] Among them, F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, and F3 is the effective focal length of the third lens group; Δf is the difference in the effective focal length change of the focusing lens group when the second lens barrel P02 moves from the position closest to the first lens barrel P01 to the position closest to the third lens barrel P03; DT2s is the light-clearing diameter on the object side of the second lens barrel P02, and DT2m is the light-clearing diameter on the image side of the second lens barrel P02; Td2 is the distance on the optical axis from the object side surface of the second lens E2 in the second lens group to the image side surface of the fifth lens E5.

[0090] It is worth noting that the focusing lens group of the present application adopts a three-barrel combination structure, in which the first to third lens groups are sequentially built in the first to third barrels, wherein the first lens group includes the first lens E1, the second lens group includes the second lens E2 to the fifth lens E5, and the third lens group includes the sixth lens E6 and the seventh lens E7. By distributing the focal lengths of the three lens groups in sequence according to "positive-positive-negative" and distributing the focal lengths of the first to seventh lenses E7 in sequence according to "positive-positive-negative-positive-positive-negative-negative" and further movably arranging the second barrel between the first barrel and the third barrel along the optical axis, the focusing lens group can take into account the imaging performance of different focal lengths such as telephoto, near focus and macro; by controlling the ratio between the sum of the focal lengths of the three lens groups and the maximum value of the effective focal length change of the focusing lens group, the focusing lens group can take into account the focusing range and imaging quality. On the one hand, constraining the ratio The lower limit enables the focusing range of the focusing lens group to cover the requirements for different focal lengths in actual use. On the other hand, when the effective focal length of the focusing lens group changes too drastically, the image clarity, distortion, etc. are difficult to control during the focusing process. By constraining the upper limit of the ratio, the impact of the rapid change of the effective focal length of the focusing lens group on the imaging quality during the focusing process can be reduced. Furthermore, the ratio of the sum of the clear diameters on the object side and image side of the second lens barrel P02 in the second lens group to the distance on the optical axis from the object side surface of the second lens E2 to the image side surface of the fifth lens E5 is controlled to be within a reasonable range. On the one hand, the appropriate clear diameter can ensure the amount of light entering the optical system in the focusing lens group, and ensure the brightness, contrast and high performance of the imaging. On the other hand, the appropriate distance on the optical axis from the object side surface of the second lens E2 to the image side surface of the fifth lens E5 will make the overall structure of the optical system compact, which is conducive to the miniaturization of the focusing lens group.

[0091] In addition, the object-side surface of the first lens E1 is convex; the object-side surface of the second lens E2 is convex; the image-side surface of the third lens E3 is concave; the object-side surface of the fourth lens E4 is convex, and the image-side surface is concave; the image-side surface of the fifth lens E5 is convex; the object-side surface of the sixth lens E6 is concave, and the image-side surface is convex; and the object-side surface of the seventh lens E7 is convex, and the image-side surface is concave.

[0092] For example, this application provides MTF curves under three schemes. Scheme 1 corresponds to Figure 12 , Option 2 corresponds to Figure 13 , Option 3 corresponds to Figure 14 , Figure 12 The MTF curve and modulation transfer function curve of the focusing lens group are shown when (F1+F2+F3) / |Δf|=5.58; Figure 13 The MTF curve and modulation transfer function curve of the focusing lens group are shown when (F1+F2+F3) / |Δf|=4.35; Figure 14 The MTF curve and modulation transfer function curve of the focusing lens group are respectively shown when (F1+F2+F3) / |Δf|=8.22 is satisfied.

[0093] It is easy to see from the figure: Figure 12 As shown in Scheme 1, when the relationship (F1+F2+F3) / |Δf| is within the range of greater than 4.95 and less than 6.25, the MTF curve of the focusing lens group is stable, so that the focusing lens group has good MTF performance; Figure 13 As shown in the figure, in the second scheme, when the relationship (F1+F2+F3) / |Δf| is within the range of less than 4.95, as the image height increases, especially when the image height is greater than 5mm, the MTF curve of the focusing lens group shows a significant drop phenomenon, and the optical performance decreases and does not meet the imaging requirements; Figure 14 As shown in the figure, in solution 3, when the relationship (F1+F2+F3) / |Δf| is greater than 5.80, the MTF of the focusing lens group fluctuates significantly with the increase of image height, and there is a significant drop when the image height is greater than 5mm, and the optical performance is reduced and does not meet the imaging requirements.

[0094] Preferably, the focusing lens group satisfies: 4.97≤(F1+F2+F3) / |Δf|≤5.84, and 2.35≤(DT2s+DT2m) / Td2≤3.26.

[0095] According to some embodiments of the present application, the second lens barrel P02 further satisfies: 0.80≤DT2s / DT2m<1.40;

[0096] Wherein, DT2s is the light-transmitting diameter of the second lens barrel P02 on the object side, and DT2m is the light-transmitting diameter of the second lens barrel P02 on the image side.

[0097] In this way, by reasonably limiting the ratio range of the light-clearing diameter of the object side of the second lens barrel P02 to the light-clearing diameter of the image side of the second lens barrel P02, firstly, it is ensured that the light is relatively uniform when passing through the second lens group, and the loss of marginal light is avoided, which causes the edge portion of the image to be darker than the central portion, forming an imaging dark corner, and affecting the overall quality of the image; secondly, during the zoom movement of the second lens group, the change in illumination and other factors can also be made smaller, and obvious differences in brightness and darkness can be avoided during the zooming process, which affects the continuous effect of zoom shooting; furthermore, by constraining the upper limit of the ratio, stray light can also be reduced. If the light-clearing diameter of the object side of the lens barrel is too large relative to the light-clearing diameter of the image side of the lens barrel, more non-imaging light may enter the system, forming a stray light background on the image plane, reducing the contrast of the image, and affecting the imaging effect.

[0098] Preferably, the second lens barrel P02 satisfies: 0.8 ≤ DT2s / DT2m ≤ 1.39.

[0099] According to some embodiments of the present application, the focusing lens group further satisfies: 2.10 < F2 / L2 ≤ 2.95 and 2.10 ≤ F2 / Td2 ≤ 2.85;

[0100] where F2 is the effective focal length of the second lens group, L2 is the maximum height of the second lens barrel P02, and Td2 is the distance on the optical axis from the object side surface of the second lens E2 to the image side surface of the fifth lens E5 in the second lens group.

[0101] In this way, reasonably controlling the ratio of the effective focal length of the second lens group to the maximum height of the second lens barrel P02 helps to ensure the mechanical stability of the optical system. First, when the ratio is within a reasonable range, the size ratio of the second lens barrel P02 and the second lens group is relatively coordinated, which is convenient for installation and fixation, and can reduce problems such as vibration and offset caused by unreasonable structure, improving the reliability and stability of the system; second, further restricting the ratio of the effective focal length of the second lens group to the distance on the optical axis from the object side surface of the second lens E2 to the image side surface of the fifth lens E5 can keep the aberration at a good level. If the distance Td2 is too short, the propagation angle of light between the lens groups changes violently, increasing the difficulty of aberration correction, and spherical aberration, coma, etc. may occur; furthermore, it avoids problems such as edge blurring and deformation when shooting distant objects. If the effective focal length is too long and the distance Td2 is relatively short at the same time, the degree of light convergence or divergence exceeds the correction ability of the lens group, which will also reduce the image quality.

[0102] Preferably, the focusing lens group satisfies: 2.13 ≤ F2 / L2 ≤ 2.95 and 2.10 ≤ F2 / Td2 ≤ 2.85.

[0103] According to some embodiments of the present application, a second spacer element P2 in contact with the image side surface of the second lens E2 is provided on the image side of the second lens E2, and the focusing lens group further satisfies: 1.65 ≤ f2 / d2s < 5.20;

[0104] where f2 is the effective focal length of the second lens E2, and d2s is the inner diameter of the object side surface of the second spacer element P2.

[0105] In this way, properly limiting the ratio of the effective focal length of the second lens element E2 to the inner diameter of the object side surface of the second spacer element P2 can reduce light loss and the assembly sensitivity of the second lens E2. If the ratio is too large, the second spacer element P2 intercepts too much light, resulting in light energy loss and reduced image brightness and contrast. If the ratio is too small, the second lens E2's ability to converge or diverge light is too strong, resulting in excessive sensitivity of the second lens E2 and excessively high assembly requirements for the second lens E2, affecting the yield rate of the second lens assembly and, by extension, the entire focusing lens assembly.

[0106] Preferably, the focusing lens group satisfies: 1.65≤f2 / d2s≤5.18.

[0107] According to some embodiments of the present application, a third spacer element P3 is provided on the image side of the third lens E3 and contacts the image side surface of the third lens E3. The focusing lens group further satisfies the following conditions: 0.50<(f3+f4) / d3s<2.15;

[0108] Wherein, f3 is the effective focal length of the third lens E3, f4 is the effective focal length of the fourth lens E4, and d3s is the inner diameter of the object side surface of the third spacing element P3.

[0109] In this way, by properly controlling the ratio of the sum of the effective focal lengths of the third lens E3 and the fourth lens E4 to the inner diameter of the object side surface of the third spacer element P3, the transition light passing through the middle of the second lens E2 system is more stable and aberrations can be corrected. On the one hand, if this ratio is small, that is, if the sum of the effective focal lengths of the third lens E3 and the fourth lens E4 is small, the third lens E3 and the fourth lens E4 will have excessive light deflection capabilities, which can easily cause significant aberrations such as coma and astigmatism at the inner edge of the third spacer element P3, resulting in distortion and blurring of the image edges. Conversely, if this ratio is too large, the third lens E3 and the fourth lens E4 will not be able to deflect light sufficiently, resulting in insufficient correction of light during propagation, which will also reduce image quality. On the other hand, under certain conditions of the effective focal lengths of the third lens element E3 and the fourth lens element E4, if the inner diameter of the object side surface of the third spacer element P3 is too large, it will introduce excess light to form stray light, affecting the imaging quality; if it is too small, it will intercept and affect the illumination, causing a sharp drop in illumination at the edge of the image plane, resulting in vignetting, affecting the imaging effect.

[0110] Preferably, the focusing lens group satisfies: 0.51≤(f3+f4) / d3s≤2.14.

[0111] According to some embodiments of the present application, the image side of the fourth lens E4 is provided with a fourth spacer element P4 in contact with the image side surface of the fourth lens E4, and the focusing lens group further satisfies: 2.15 <f4 / d4m<3.45;

[0112] Wherein, f4 is the effective focal length of the fourth lens E4, and d4m is the inner diameter of the image side surface of the fourth spacer element P4.

[0113] In this way, by appropriately limiting the ratio of the effective focal length of the fourth lens element E4 to the inner diameter of the image-side surface of the fourth spacer element P4, the effective focal length of the fourth lens element E4 is more precisely controlled, thereby controlling the amount of light passing through the fourth lens element E4 and the inner diameter of the fourth spacer element P4, and thus the light distribution. Maintaining the effective focal length of the fourth lens E4 within an appropriate range ensures a high overall illumination level. Maintaining the inner diameter of the image-side surface of the fourth spacer element P4 within an appropriate range controls the amount of light passing through the edge of the image, thereby ensuring high illumination levels at the edge. This results in a superior image quality with no back-bow or abrupt drops in illumination.

[0114] Preferably, the focusing lens group satisfies: 2.16≤f4 / d4m≤3.42.

[0115] According to some embodiments of the present application, the focusing lens assembly further satisfies: 4.95≤DT2m / (CT5×N5)<11.95;

[0116] Wherein, DT2m is the clear diameter of the image side of the second lens barrel P02, CT5 is the center thickness of the fifth lens E5, and N5 is the refractive index of the fifth lens E5.

[0117] In this way, the ratio of the image-side clear diameter of the second lens barrel P02 to the center thickness of the fifth lens element E5 and the refractive index of the fifth lens element E5 is reasonably limited. On the one hand, under the condition that the image-side clear diameter of the second lens barrel P02 remains unchanged, the light rays at the center thickness of the fifth lens element E5 (i.e., the optical path at the center of the fifth lens element E5) are reasonably distributed, thereby making room for the multiple lenses of the second lens group. On the other hand, under the condition that the center thickness and refractive index of the fifth lens element E5 remain unchanged, the aperture of the outgoing light rays of the second lens group is controlled to ensure sufficient outgoing light rays while intercepting excess stray light rays. On the other hand, this is conducive to improving the assembly convenience and accuracy of the second lens group. When the ratio is appropriate, the sizes of the second lens barrel P02 and the fifth lens element E5 are reasonably matched, facilitating the use of conventional assembly processes, ensuring the concentricity and relative position accuracy of the lens and the lens barrel, and reducing the impact of assembly errors on optical performance.

[0118] Preferably, the focusing lens group satisfies: 4.95≤DT2m / (CT5×N5)≤11.93.

[0119] According to some embodiments of the present application, the focusing lens group further satisfies: 3.35 < DT2s / (CT2 × N2) < 6.45;

[0120] Where, DT2s is the clear aperture diameter of the object side of the second lens barrel P02, CT2 is the central thickness of the second lens E2, and N2 is the refractive index of the second lens E2.

[0121] Thus, similarly, by reasonably restricting the ratio of the clear aperture diameter of the object side of the second lens barrel P02 to the central thickness of the second lens E2 and the refractive index of the second lens E2, on the one hand, under the condition that the clear aperture diameter of the object side of the second lens barrel P02 remains unchanged, the light is reasonably distributed in the central thickness of the second lens E2 (i.e., the optical path at the center of the second lens E2), leaving space for the other multiple lenses in the second lens group; under the condition that the optical path in the second lens E2 remains unchanged, the incident light angle of the second lens group is controlled to ensure sufficient incident light while intercepting excess stray light. On the other hand, it is beneficial to improve the assembly convenience and accuracy of the second lens group. When the ratio is appropriate, the sizes of the second lens barrel P02 and the second lens E2 are reasonably matched, facilitating the use of conventional assembly processes, ensuring the concentricity and relative position accuracy of the lens and the lens barrel, and reducing the influence of assembly errors on the optical performance.

[0122] Preferably, the focusing lens group satisfies: 3.39 ≤ DT2s / (CT2 × N2) ≤ 6.42.

[0123] According to some embodiments of the present application, the focusing lens group satisfies: -3.50 < F3 / L3 ≤ -2.55 and 0.80 ≤ Td3 / L3 < 0.95;

[0124] Where, L3 is the maximum height of the third lens barrel P03 along the optical axis direction, F3 is the effective focal length of the third lens group, and Td3 is the distance on the optical axis from the object side surface of the sixth lens E6 to the image side surface of the seventh lens E7 in the third lens group.

[0125] In this way, reasonable control of the ratio of the effective focal length of the third lens group to the maximum height of the third lens barrel P03 along the optical axis helps to ensure the mechanical stability of the optical system. When the ratio is within a reasonable range, the size ratio of the third lens barrel P03 and the third lens group is relatively coordinated, which is convenient for installation and fixation, can reduce problems such as vibration and offset caused by unreasonable structure, and improve the reliability and stability of the system. Further limiting the ratio of the distance from the object side surface of the sixth lens E6 to the image side surface of the seventh lens E7 on the optical axis to the maximum height of the third lens barrel P03 along the optical axis ensures that the third lens group does not protrude from the outer end of the lens barrel as much as possible when assembled in the third lens barrel P03. Even if it protrudes, the object side surface of the third lens group is only allowed to protrude a little toward the second lens group, so as to avoid the third lens group protruding too much from the third lens barrel P03 and contacting with the second lens group or with other module structures located on the image side of the third lens group (such as Figure 1 The prism E8 and filter E9 in the image processing unit collide with each other, resulting in poor appearance.

[0126] Preferably, the focusing lens group satisfies: -3.49≤F3 / L3≤-2.55 and 0.8≤Td3 / L3≤0.92.

[0127] According to some embodiments of the present application, the focusing lens assembly further satisfies: 3.65<|F3| / (L3-T67)≤5.10;

[0128] Wherein, F3 is the effective focal length of the third lens group, L3 is the maximum height of the third lens barrel P03 along the optical axis, and T67 is the air distance between the sixth lens E6 and the seventh lens E7 on the optical axis.

[0129] In this way, reasonably limiting the ratio of the effective focal length of the third lens group to the maximum height of the third lens barrel P03 and the difference in the air spacing between the sixth lens element E6 and the seventh lens element E7 on the optical axis helps, on the one hand, to ensure the thickness and spacing of the sixth lens element E6 and the seventh lens element E7, thus ensuring the strength and workability of both lenses. A suitable air spacing also ensures the stability of the third lens group. Furthermore, as the entire optical system passes through the third lens group and emerges at the image plane, controlling the effective focal length of the third lens group helps improve aberrations. If light rays are excessively converged or divergent after being refracted by the third lens group and then directly emerge at the image plane, aberrations such as spherical aberration and coma will increase, resulting in reduced resolution and difficulty in distinguishing image details, affecting image clarity.

[0130] Preferably, the focusing lens group satisfies: 3.69≤|F3| / (L3-T67)≤5.10.

[0131] According to some embodiments of the present application, the focusing lens group further satisfies: 0.40 <ET6 / (CT6+T67)≤0.95;

[0132] Wherein, ET6 is the maximum thickness of the non-light-transmitting area of the sixth lens E6, CT6 is the central thickness of the sixth lens E6, and T67 is the air gap between the sixth lens E6 and the seventh lens E7 on the optical axis.

[0133] In this way, by reasonably controlling the ratio of the maximum thickness of the non-light-transmitting area of the sixth lens E6 to the sum of the central thickness of the sixth lens E6 and the air gap between the sixth lens E6 and the seventh lens E7 on the optical axis, parameters such as the edge thickness and central thickness of the sixth lens E6 are ensured to meet the molding requirements, with good processability, and the occurrence of poor molding problems is avoided. It can also make the cooperation between the sixth lens E6 and the seventh lens E7 more stable. When affected by external factors such as vibration and temperature change, the optical performance can be better maintained, and the decrease in imaging quality caused by the change of the lens structure and the air gap between the sixth lens E6 and the seventh lens E7 on the optical axis can be reduced.

[0134] Preferably, the focusing lens group satisfies: 0.43 ≤ ET6 / (CT6 + T67) ≤ 0.91.

[0135] According to some embodiments of the present application, the focusing lens group further satisfies: 0.35 < ET7 / (T67 + CT7) < 1.10;

[0136] Wherein, ET7 is the maximum thickness of the non-light-transmitting area of the seventh lens E7, CT7 is the central thickness of the seventh lens E7, and T67 is the air gap between the sixth lens E6 and the seventh lens E7 on the optical axis.

[0137] In this way, similarly, by reasonably controlling the ratio of the maximum thickness of the non-light-transmitting area of the seventh lens E7 to the sum of the central thickness of the seventh lens E7 and the air gap between the sixth lens E6 and the seventh lens E7 on the optical axis, parameters such as the edge thickness and central thickness of the seventh lens E7 are ensured to meet the molding requirements, with good processability, and the occurrence of poor molding problems is avoided. It can also make the cooperation between the sixth lens E6 and the seventh lens E7 more stable. When affected by external factors such as vibration and temperature change, the optical performance can be better maintained, and the decrease in imaging quality caused by the change of the lens structure and the air gap between the sixth lens E6 and the seventh lens E7 on the optical axis can be reduced.

[0138] Preferably, the focusing lens group satisfies: 0.37 ≤ ET7 / (T67 + CT7) ≤ 1.08.

[0139] According to some embodiments of the present application, the focusing lens group satisfies: 1.45 < F1 / F2 < 2.45 and -3.60 < F1 / F3 ≤ -2.10;

[0140] Wherein, F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, and F3 is the effective focal length of the third lens group.

[0141] In this way, reasonably limiting the ratio of the effective focal length of the first lens group to the effective focal length of the second lens group, and the ratio of the effective focal length of the first lens group to the effective focal length of the third lens group, on the one hand, helps to balance the optical effects between the different lens groups, thereby better correcting aberrations such as spherical aberration and coma. The first lens group, the second lens group, and the third lens group cooperate with each other to achieve clearer and sharper images. On the other hand, it is conducive to the balance of light propagation and energy distribution, preventing the majority of light from focusing on a single lens group or excessive divergence from a single lens group, affecting the overall image brightness and contrast. This also avoids redundant system design and fully utilizes the advantages of multiple lens groups to ensure more reasonable light propagation and energy distribution among the three lens groups.

[0142] Preferably, the focusing lens group satisfies: 1.48≤F1 / F2≤2.43 and -3.59≤F1 / F3≤-2.1.

[0143] According to some embodiments of the present application, the focusing lens assembly further satisfies: 1.70≤(T12+T56) / ΔEP0<2.20;

[0144] Wherein, T12 is the air distance between the first lens E1 and the second lens E2 on the optical axis, T56 is the air distance between the fifth lens E5 and the sixth lens E6 on the optical axis, and ΔEP0 is the movable distance of the second lens barrel P02 along the optical axis.

[0145] In this way, by properly controlling the ratio of the sum of the air spacing on the optical axis between the first lens E1 and the second lens E2, and the air spacing on the optical axis between the fifth lens E5 and the sixth lens E6, to the maximum distance that the second lens barrel P02 can move along the optical axis, it is possible to ensure that the change in the air spacing between the lenses matches the change in focal length as the lens barrel moves. When the second lens barrel P02 moves along the optical axis, by adjusting the air spacing between the first and second lenses and the fifth and sixth lenses, a smooth zooming process is achieved, avoiding focal length jumps or degradation in image quality. Furthermore, controlling the distance between the second lens group, the first lens group, and the third lens group prevents collisions and damage to the lens groups during zooming.

[0146] Preferably, the focusing lens group satisfies: 1.7≤(T12+T56) / ΔEP0≤2.18.

[0147] According to some embodiments of the present application, the focusing lens assembly further satisfies: 4.40<(L1+L2+L3) / ΔEP0<5.55;

[0148] Among them, L1 is the maximum height of the first lens barrel P01 along the optical axis, L2 is the maximum height of the second lens barrel P02 along the optical axis, L3 is the maximum height of the third lens barrel P03 along the optical axis, and ΔEP0 is the maximum distance that the second lens barrel P02 can move along the optical axis.

[0149] Thus, by reasonably limiting the ratio of the sum of the maximum heights of the first lens barrel P01, the second lens barrel P02, and the third lens barrel P03 to the maximum distance that the second lens barrel P02 can move along the optical axis, the mechanical structure of the optical system can be made more compact and space utilization can be improved. If the ratio is large, that is, the total height of the three lens barrels is too large relative to the maximum distance that the second lens barrel P02 can move along the optical axis, the entire system may appear too tall, occupying too much space, which is not conducive to the miniaturization and portability of the device. If the ratio is small, the total height of the three lens barrels is relatively low, and the travel distance of the second lens barrel P02 is too long, which may make the structure too loose and increase the lateral size of the system. Keeping the ratio within this range helps to make the system structure more compact and reasonable while ensuring optical performance.

[0150] Preferably, the focusing lens group satisfies: 4.42≤(L1+L2+L3) / ΔEP0≤5.53.

[0151] It should be noted that those skilled in the art will appreciate that, without departing from the claimed technical solution, the number of spacer elements comprising the focusing lens assembly may be varied to achieve the various results and advantages described herein, and this application does not impose any specific limitations thereon. For example, the focusing lens assembly may include a different number of spacer elements than that described in the above embodiment, as desired.

[0152] Some specific but non-limiting examples of the above-mentioned embodiments of the present application are described in more detail below with reference to the accompanying drawings. For ease of description, in the following embodiments, OBJ represents the object plane of the focusing lens group, STO represents the surface of the aperture, S1 represents the object-side surface of the first lens E1, S2 represents the image-side surface of the first lens E1, S3 represents the object-side surface of the second lens E2, S4 represents the image-side surface of the second lens E2, S5 represents the object-side surface of the third lens E3, S6 represents the image-side surface of the third lens E3, S7 represents the object-side surface of the fourth lens E4, and S8 represents the image-side surface of the fourth lens E4; S9 represents the object-side surface of the fifth lens E5, S10 represents the image-side surface of the fifth lens E5, S11 represents the object-side surface of the sixth lens E6, S12 represents the image-side surface of the sixth lens E6, S13 represents the object-side surface of the seventh lens E7, S14 represents the image-side surface of the seventh lens E7, S15 represents the object-side surface of the prism E8, S16 represents the image-side surface of the prism E8, S17 represents the object-side surface of the filter E9, S18 represents the image-side surface of the filter E9, and S19 represents the image plane. In addition, Aj represents the j-th order aspheric coefficient, j=4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30.

[0153] It is worth noting that the following three embodiments each include multiple working conditions, and the differences between the multiple working conditions in each embodiment lie in some structural dimension parameters of the lens barrel and the spacer element.

[0154] Example 1

[0155] like Figure 1 、 Figure 2 and Figures 3A to 3C As shown, Figures 3A to 3C They are respectively structural schematic diagrams of the focusing lens group of Example 1 in three working conditions. In this embodiment, the focusing lens group includes a first lens barrel P01, a second lens barrel P02 and a third lens barrel P03 arranged in sequence along the optical axis from the object side to the image side. The first lens barrel P01 has a built-in first lens group, which includes a first lens E1; the second lens barrel P02 has a built-in second lens group, which includes second to fifth lenses E2 to E5; the third lens barrel P03 has a built-in third lens group, which includes a sixth lens E6 and a seventh lens E7; the three lens groups distribute optical power according to "positive-positive-negative", and the seven lenses distribute optical power according to "positive-positive-negative-positive-positive-negative-negative".

[0156] In this embodiment, at least one spacer element is included between any two adjacent lenses in the second lens group. The plurality of spacers are sequentially divided into a second spacer element P2, a third spacer element P3, and a fourth spacer element P4 from the object side to the image side. The object-side surface and the image-side surface of the second spacer element P2 are in contact with the image-side surface of the second lens E2 and the object-side surface of the third lens E3, respectively. The object-side surface and the image-side surface of the third spacer element P3 are in contact with the image-side surface of the third lens E3 and the object-side surface of the fourth lens E4, respectively. The object-side surface and the image-side surface of the fourth spacer element P4 are in contact with the image-side surface of the fourth lens E4 and the object-side surface of the fifth lens E5, respectively.

[0157] In this embodiment, the third lens group further includes a sixth spacer element P6 , the object-side surface and the image-side surface of the sixth spacer element P6 are in contact with the image-side surface of the sixth lens E6 and the object-side surface of the seventh lens E7 , respectively.

[0158] In this embodiment, the object-side surface S1 of the first lens element E1 is convex, and the image-side surface S2 is convex; the object-side surface S3 of the second lens element E2 is convex, and the image-side surface S4 is concave; the object-side surface S5 of the third lens element E3 is convex, and the image-side surface S6 is concave; the object-side surface S7 of the fourth lens element E4 is convex, and the image-side surface S8 is concave; the object-side surface S9 of the fifth lens element E5 is convex, and the image-side surface S10 is convex; the object-side surface S11 of the sixth lens element E6 is concave, and the image-side surface S12 is convex; and the object-side surface S13 of the seventh lens element E7 is convex, and the image-side surface S14 is concave.

[0159] It is worth noting that, in this embodiment, the first lens E1 is made of glass, and the second lens E2 to the seventh lens E7 are made of plastic, which helps to reduce the weight of the entire focusing lens assembly.

[0160] In summary, some structural parameters of the lens barrel and the spacer element of the focusing lens assembly in Example 1 under working conditions 1-1, 1-2, and 1-3 are shown in the following Table 8.

[0161] In addition, Table 1 shows the basic optical parameters of the focusing lens assembly of Example 1, wherein the units of the curvature radius, thickness / distance, and effective radius are all in millimeters (mm).

[0162] Table 1: Basic optical parameters of the focusing lens assembly of Example 1

[0163]

[0164] It should be noted that the materials in Table 1 include refractive indices and Abbe numbers. For example, the materials 1.489 and 70.420 of S1 in Table 1 respectively indicate that the refractive index of the first lens E1 is 1.489 and the Abbe number is 70.420.

[0165] 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. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0166] ;

[0167] Where x is the distance vector from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; and Ai is the correction coefficient for the i-th order of the aspheric surface. Table 2 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, 18, 20, 22, 24, 26, 28, and 30 that can be used for each aspheric mirror surface S1 to S14 in Example 1.

[0168] Table 2: Aspheric coefficients of the focusing lens assembly of Example 1

[0169]

[0170] like Figures 4A to 4C and Figures 5A to 5C As shown, Figures 4A to 4C They are respectively the axial chromatic aberration curve, the astigmatism curve and the distortion curve of the focusing lens assembly shown in Example 1 when the object distance is infinite, Figures 5A to 5C They are respectively the axial chromatic aberration curve, astigmatism curve and distortion curve of the focusing lens assembly shown in Example 1 when the object distance is 57.8556 mm. Figures 4A to 4C and Figures 5A to 5C It can be seen that the focusing lens assembly provided in Example 1 has good optical performance and imaging effect.

[0171] Example 2

[0172] like Figure 1 、 Figure 2 and Figures 6A to 6C As shown, Figures 6A to 6C They are respectively schematic structural diagrams of the focusing lens group of Example 2 in three working conditions. In this embodiment, the focusing lens group includes a first lens barrel P01, a second lens barrel P02 and a third lens barrel P03 arranged in sequence along the optical axis from the object side to the image side. The first lens barrel P01 has a built-in first lens group, which includes a first lens E1; the second lens barrel P02 has a built-in second lens group, which includes second to fifth lenses E2 to E5; the third lens barrel P03 has a built-in third lens group, which includes a sixth lens E6 and a seventh lens E7; the three lens groups distribute optical power according to "positive-positive-negative", and the seven lenses distribute optical power according to "positive-positive-negative-positive-positive-negative-negative".

[0173] In this embodiment, at least one spacer element is included between any two adjacent lenses in the second lens group. The plurality of spacers are sequentially divided into a second spacer element P2, a third spacer element P3, and a fourth spacer element P4 from the object side to the image side. The object-side surface and the image-side surface of the second spacer element P2 are in contact with the image-side surface of the second lens E2 and the object-side surface of the third lens E3, respectively. The object-side surface and the image-side surface of the third spacer element P3 are in contact with the image-side surface of the third lens E3 and the object-side surface of the fourth lens E4, respectively. The object-side surface and the image-side surface of the fourth spacer element P4 are in contact with the image-side surface of the fourth lens E4 and the object-side surface of the fifth lens E5, respectively.

[0174] In this embodiment, the third lens group further includes a sixth spacer element P6 , the object-side surface and the image-side surface of the sixth spacer element P6 are in contact with the image-side surface of the sixth lens E6 and the object-side surface of the seventh lens E7 , respectively.

[0175] In this embodiment, the object-side surface S1 of the first lens element E1 is convex, and the image-side surface S2 is concave; the object-side surface S3 of the second lens element E2 is convex, and the image-side surface S4 is concave; the object-side surface S5 of the third lens element E3 is concave, and the image-side surface S6 is concave; the object-side surface S7 of the fourth lens element E4 is convex, and the image-side surface S8 is concave; the object-side surface S9 of the fifth lens element E5 is convex, and the image-side surface S10 is convex; the object-side surface S11 of the sixth lens element E6 is concave, and the image-side surface S12 is convex; and the object-side surface S13 of the seventh lens element E7 is convex, and the image-side surface S14 is concave.

[0176] It is worth noting that, in this embodiment, the first lens E1 is made of glass, and the second lens E2 to the seventh lens E7 are made of plastic, which helps to reduce the weight of the entire focusing lens assembly.

[0177] In summary, some structural parameters of the lens barrel and the spacer element of the focusing lens assembly in Example 2 under working conditions 2-1, 2-2, and 2-3 are shown in the following Table 8.

[0178] In addition, Table 3 shows the basic optical parameters of the focusing lens assembly of Example 2, wherein the units of the curvature radius, thickness / distance, and effective radius are all millimeters (mm).

[0179] Table 3: Basic optical parameters of the focusing lens assembly of Example 2

[0180]

[0181] It should be noted that the materials in Table 3 include refractive indices and Abbe numbers. For example, the materials 1.498 and 81.56 of S1 in Table 3 respectively indicate that the refractive index of the first lens E1 is 1.498 and the Abbe number is 81.56.

[0182] 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. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0183] ;

[0184] Where x is the distance vector from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; and Ai is the correction coefficient for the i-th order of the aspheric surface. Table 4 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, 18, 20, 22, 24, 26, 28, and 30 that can be used for each aspheric mirror surface S1 to S14 in Example 2.

[0185] Table 4: Aspheric coefficients of the focusing lens assembly of Example 2

[0186]

[0187] like 7A to 7C and Figures 8A to 8C As shown, 7A to 7C They are respectively the axial chromatic aberration curve, astigmatism curve and distortion curve of the focusing lens assembly shown in Example 2 when the object distance is infinite, Figures 8A to 8C They are respectively the axial chromatic aberration curve, astigmatism curve and distortion curve of the focusing lens group shown in Example 2 when the object distance is 52.6455 mm. 7A to 7C and Figures 8A to 8C It can be seen that the focusing lens assembly provided in the second embodiment has good optical performance and imaging effect.

[0188] Example 3

[0189] like Figure 1 、 Figure 2 and Figures 9A to 9C As shown, Figures 9A to 9C They are respectively schematic structural diagrams of the focusing lens group of Example 3 in three working conditions. In this embodiment, the focusing lens group includes a first lens barrel P01, a second lens barrel P02 and a third lens barrel P03 arranged in sequence along the optical axis from the object side to the image side. The first lens barrel P01 has a built-in first lens group, which includes a first lens E1; the second lens barrel P02 has a built-in second lens group, which includes second to fifth lenses E2 to E5; the third lens barrel P03 has a built-in third lens group, which includes a sixth lens E6 and a seventh lens E7; the three lens groups distribute optical power according to "positive-positive-negative", and the seven lenses distribute optical power according to "positive-positive-negative-positive-positive-negative-negative".

[0190] In this embodiment, at least one spacer element is included between any two adjacent lenses in the second lens group. The plurality of spacers are sequentially divided into a second spacer element P2, a third spacer element P3, and a fourth spacer element P4 from the object side to the image side. The object-side surface and the image-side surface of the second spacer element P2 are in contact with the image-side surface of the second lens E2 and the object-side surface of the third lens E3, respectively. The object-side surface and the image-side surface of the third spacer element P3 are in contact with the image-side surface of the third lens E3 and the object-side surface of the fourth lens E4, respectively. The object-side surface and the image-side surface of the fourth spacer element P4 are in contact with the image-side surface of the fourth lens E4 and the object-side surface of the fifth lens E5, respectively.

[0191] In this embodiment, the third lens group further includes a sixth spacer element P6 , the object-side surface and the image-side surface of the sixth spacer element P6 are in contact with the image-side surface of the sixth lens E6 and the object-side surface of the seventh lens E7 , respectively.

[0192] In this embodiment, the object-side surface S1 of the first lens element E1 is convex, and the image-side surface S2 is concave; the object-side surface S3 of the second lens element E2 is convex, and the image-side surface S4 is convex; the object-side surface S5 of the third lens element E3 is concave, and the image-side surface S6 is concave; the object-side surface S7 of the fourth lens element E4 is convex, and the image-side surface S8 is concave; the object-side surface S9 of the fifth lens element E5 is concave, and the image-side surface S10 is convex; the object-side surface S11 of the sixth lens element E6 is concave, and the image-side surface S12 is convex; and the object-side surface S13 of the seventh lens element E7 is convex, and the image-side surface S14 is concave.

[0193] It is worth noting that, in this embodiment, the first lens E1 is made of glass, and the second lens E2 to the seventh lens E7 are made of plastic, which helps to reduce the weight of the entire focusing lens assembly.

[0194] In summary, some structural parameters of the lens barrel and the spacer element of the focusing lens assembly in Example 3 under working conditions 3-1, 3-2, and 3-3 are shown in the following Table 8.

[0195] In addition, Table 5 shows the basic optical parameters of the focusing lens assembly of Example 3, wherein the units of the curvature radius, thickness / distance and effective radius are all millimeters (mm).

[0196] Table 5: Basic optical parameters of the focusing lens assembly of Example 3

[0197]

[0198] It should be noted that the materials in Table 5 include refractive indices and Abbe numbers. For example, the materials 1.489 and 70.420 of S1 in Table 5 respectively indicate that the refractive index of the first lens E1 is 1.489 and the Abbe number is 70.420.

[0199] 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. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0200] ;

[0201] Where x is the distance vector from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; and Ai is the correction coefficient for the i-th order of the aspheric surface. Table 6 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, 18, 20, 22, 24, 26, 28, and 30 that can be used for each aspheric mirror surface S1 to S14 in Example 3.

[0202] Table 6: Aspheric coefficients of the focusing lens assembly of Example 3

[0203]

[0204] like 10A to 10C and Figures 11A to 11C As shown, Figures 10A to 10C They are respectively the axial chromatic aberration curve, astigmatism curve and distortion curve of the focusing lens assembly shown in Example 3 when the object distance is infinite, Figures 11A to 11C They are respectively the axial chromatic aberration curve, astigmatism curve and distortion curve of the focusing lens group shown in Example 3 when the object distance is 66.6675 mm. 10A to 10C and Figures 11A to 11C It can be seen that the focusing lens assembly provided in the third embodiment has good optical performance and imaging effect.

[0205] In summary, in Examples 1 to 3, the effective focal lengths F1 to F3 of the first to third lens groups in the focusing lens group, the effective focal length f of the focusing lens group at object distances of infinity and close distance, and the aperture coefficient Fno of the focusing lens group are respectively shown in Table 7 below.

[0206] Table 7: System optical parameters of focusing lens group

[0207]

[0208] In addition, some structural parameters (DT2s, DT2m, d2s, d3s, d4m, L1, L2, L3, ΔEP0, ET6, ET7) of the lens barrel and spacer element of the focusing lens assembly in Examples 1 to 3 are specifically shown in Table 8.

[0209] Table 8: Partial structural parameters of focusing lens group

[0210]

[0211] In summary, the focusing lens groups in Examples 1 to 3 satisfy the relationship shown in Table 9:

[0212] Table 9: Relationships satisfied by the focusing lens group

[0213]

[0214] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0215] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A focusing lens assembly, characterized by: It includes a first lens barrel, a second lens barrel and a third lens barrel arranged in sequence along the same optical axis, and the second lens barrel is movably arranged between the first lens barrel and the third lens barrel; A first lens group is installed in the first lens barrel, and the first lens group includes a first lens with a positive focal power; A second lens group is installed in the second lens barrel, the second lens group has a positive focal power, and the second lens group includes a second lens with a positive focal power, a third lens with a negative focal power, a fourth lens with a positive focal power and a fifth lens with a positive focal power; A third lens group is installed in the third lens barrel, the third lens group has a negative focal power, and the third lens group includes a sixth lens with a negative focal power and a seventh lens with a negative focal power; At least one spacer element is included between any two adjacent lenses in the second lens group, and the object side surface of the spacer element contacts the adjacent lens; The focusing lens group satisfies: 4.95 < (F1 + F2 + F3) / |Δf| < 5.85; and 2.35 ≤ (DT2s + DT2m) / Td2 ≤ 3.30; Where, 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; △f is the difference in the effective focal length of the focusing lens group when the second lens barrel moves from the position closest to the first lens barrel to the position closest to the third lens barrel; DT2s is the clear aperture diameter on the object side of the second lens barrel, DT2m is the clear aperture diameter on the image side of the second lens barrel; Td2 is the distance on the optical axis from the object side surface of the second lens to the image side surface of the fifth lens in the second lens group.

2. The focusing lens assembly according to claim 1, wherein: The second lens barrel satisfies: 0.80 ≤ DT2s / DT2m < 1.40; Where, DT2s is the clear aperture diameter on the object side of the second lens barrel, DT2m is the clear aperture diameter on the image side of the second lens barrel.

3. The focusing lens assembly according to claim 1, wherein: The focusing lens group satisfies: 2.10 < F2 / L2 ≤ 2.95; and 2.10 ≤ F2 / Td2 ≤ 2.85; Where, F2 is the effective focal length of the second lens group, L2 is the maximum height of the second lens barrel, Td2 is the distance on the optical axis from the object side surface of the second lens to the image side surface of the fifth lens in the second lens group.

4. The focusing lens assembly according to claim 1, wherein: A second spacer element that contacts the image side surface of the second lens is provided on the image side of the second lens, and the focusing lens group further satisfies: 1.65 ≤ f2 / d2s < 5.20; Where, f2 is the effective focal length of the second lens, d2s is the inner diameter of the object side surface of the second spacer element.

5. The focusing lens assembly according to claim 1, wherein: A third spacer element that contacts the image side surface of the third lens is provided on the image side of the third lens, and the focusing lens group further satisfies: 0.50 < (f3 + f4) / d3s < 2.15; Where, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, d3s is the inner diameter of the object side surface of the third spacer element.

6. The focusing lens assembly according to claim 1, wherein: A fourth spacer element that contacts the image side surface of the fourth lens is provided on the image side of the fourth lens, and the focusing lens group further satisfies: 2.15 <f4 / d4m<3.45; Wherein, f4 is the effective focal length of the fourth lens, and d4m is the inner diameter of the image side surface of the fourth spacer element.

7. The focusing lens assembly according to claim 1, wherein: The focusing lens assembly also satisfies: 4.95≤DT2m / (CT5×N5)<11.95; Wherein, DT2m is the light-transmitting diameter of the second lens barrel on the image side, CT5 is the center thickness of the fifth lens, and N5 is the refractive index of the fifth lens.

8. The focusing lens assembly according to claim 1, wherein: The focusing lens assembly also satisfies: 3.35 <DT2s / (CT2×N2)<6.45; Wherein, DT2s is the clear diameter of the second lens barrel on the object side, CT2 is the center thickness of the second lens, and N2 is the refractive index of the second lens.

9. The focusing lens assembly according to claim 1, wherein: The focusing lens group satisfies: -3.50 <F3 / L3≤-2.55; and 0.80≤Td3 / L3<0.95; Wherein, L3 is the maximum height of the third lens barrel along the optical axis, F3 is the effective focal length of the third lens group, and Td3 is the distance on the optical axis from the object side surface of the sixth lens in the third lens group to the image side surface of the seventh lens.

10. The focusing lens assembly according to claim 1, wherein: The focusing lens assembly also satisfies: 3.65<|F3| / (L3-T67)≤5.10; Wherein, F3 is the effective focal length of the third lens group, L3 is the maximum height of the third lens barrel along the optical axis, and T67 is the air distance between the sixth lens and the seventh lens on the optical axis.

11. The focusing lens assembly according to claim 1, wherein: The focusing lens assembly also satisfies: 0.40 <ET6 / (CT6+T67)<0.95; ET6 is the maximum thickness of the non-light-transmitting area of the sixth lens, CT6 is the center thickness of the sixth lens, and T67 is the air gap between the sixth lens and the seventh lens on the optical axis.

12. The focusing lens assembly according to claim 1, wherein: The focusing lens assembly also satisfies: 0.35 <ET7 / (T67+CT7)<1.10; ET7 is the maximum thickness of the non-light-transmitting area of the seventh lens, CT7 is the center thickness of the seventh lens, and T67 is the air gap between the sixth lens and the seventh lens on the optical axis.

13. The focusing lens assembly according to any one of claims 1 to 12, wherein: The focusing lens group satisfies: 1.45 <F1 / F2<2.45; and -3.60 <F1 / F3≤-2.10; Wherein, F1 is the effective focal length of the first lens group, F2 is the effective focal length of the second lens group, and F3 is the effective focal length of the third lens group.

14. The focusing lens assembly according to any one of claims 1 to 12, wherein: The focusing lens assembly also satisfies: 1.70≤(T12+T56) / ΔEP0<2.20; Wherein, T12 is the air distance between the first lens and the second lens on the optical axis, T56 is the air distance between the fifth lens and the sixth lens on the optical axis, and ΔEP0 is the maximum distance that the second lens barrel can move along the optical axis.

15. The focusing lens assembly according to any one of claims 1 to 12, wherein: The focusing lens assembly also satisfies: 4.40<(L1+L2+L3) / ΔEP0<5.55; Among them, L1 is the maximum height of the first lens barrel along the optical axis, L2 is the maximum height of the second lens barrel along the optical axis, L3 is the maximum height of the third lens barrel along the optical axis, and ΔEP0 is the maximum distance that the second lens barrel can move along the optical axis.

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