Optical lens set

Abstract

The application provides an optical lens set. The optical lens set comprises, along an optical axis from a light ray incident side to a light ray emission side, a first lens, a diaphragm, a second lens, a third lens and a fourth lens in sequence, wherein a surface close to the incident side of the first lens is a convex surface, and a surface close to the emission side of the first lens is a convex surface; an on-axis distance BFL from a surface close to the emission side of the fourth lens to an imaging surface and an effective focal length f of the optical lens set satisfy 0.6 < BFL / f < 0.8; and an on-axis distance BFL from the surface close to the emission side of the fourth lens to the imaging surface and an on-axis distance TTL from a surface close to the incident side of the first lens to the imaging surface satisfy 0.5 < BFL / TTL < 0.7. The application solves the problem that long focal length, large aperture and high image quality are difficult to be simultaneously considered in the prior art.

Description

[0001] This application is a divisional application of the patent application with the application number 202111518805.1, titled "Optical Lens Group", which was submitted to the China National Intellectual Property Administration on December 13, 2021. Technical Field

[0002] The present invention relates to the technical field of optical imaging devices, and specifically, to an optical lens group. Background Art

[0003] With the continuous improvement of people's requirements for the photo-taking quality and various performance aspects of mobile phones, optical lens groups with characteristics such as telephoto, wide-angle, large image plane, and large aperture are constantly updated, and the images taken by mobile phones are becoming clearer and clearer, which are deeply loved by the majority of consumers.

[0004] Currently, in the prior art, an optical lens group is provided. This optical lens group has the characteristic of telephoto, but the relative aperture size is difficult to meet the user's requirements, resulting in a poor imaging effect and poor clarity when shooting objects at a relatively long distance, and it is difficult to ensure that enough imaging light enters the optical system in a relatively dark environment, which is likely to affect the final imaging quality, making the imaging effect of the photos taken in a dark scene environment poor.

[0005] That is to say, there is a problem in the optical lens group in the prior art that it is difficult to simultaneously achieve telephoto, large aperture, and high image quality. Summary of the Invention

[0006] The main purpose of the present invention is to provide an optical lens group to solve the problem in the optical lens group in the prior art that it is difficult to simultaneously achieve telephoto, large aperture, and high image quality.

[0007] To achieve the above object, according to one aspect of the present invention, an optical lens group is provided, which sequentially includes, along the optical axis from the light incident side to the light exit side: a first lens, the surface of which close to the incident side is a convex surface, and the surface close to the exit side is a convex surface; an aperture stop; a second lens; a third lens; a fourth lens; wherein, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy: 0.9 < f / TTL < 1; the on-axis distance BFL from the surface of the fourth lens close to the exit side to the imaging surface and the effective focal length f of the optical lens group satisfy: 0.6 < BFL / f < 0.8.

[0008] Furthermore, the on-axis distance BFL from the surface of the fourth lens close to the exit side to the imaging surface and the on-axis distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy: 0.5 < BFL / TTL < 0.7.

[0009] Furthermore, the distance SD from the aperture stop to the surface of the fourth lens near the exit side on the optical axis and the distance TD from the surface of the first lens near the incident side to the surface of the fourth lens near the exit side on the optical axis satisfy the following condition: 0.5 <SD / TD<0.8。

[0010] Furthermore, the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy the following relationship: 0.3 <f1 / f<0.6。

[0011] Furthermore, the effective focal length f1 of the first lens and the radius of curvature R1 of the surface of the first lens near the incident side satisfy the following relationship: 0.5 <R1 / f1<1。

[0012] Furthermore, the air gap T23 between the second and third lenses on the optical axis satisfies the condition ∑AT between the sum of the air gaps ∑AT between any two adjacent lenses from the first to the fourth lenses: 0.5 <T23 / ∑AT<1。

[0013] Furthermore, the center thickness CT2 of the second lens on the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: 0.5 <CT2 / CT3<1.1。

[0014] Furthermore, the center thickness CT1 of the first lens on the optical axis and the sum of the center thicknesses ∑CT of the first to fourth lenses on the optical axis satisfy the following relationship: 0.35 <CT1 / ∑CT<0.5。

[0015] Furthermore, the Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy the following relationship: 0.4 <V2 / V1<0.5。

[0016] Furthermore, the refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy the following relationship: 0.8 <N3 / N2<1.1。

[0017] Furthermore, the maximum effective radius DT11 of the surface of the first lens near the incident side and the maximum effective radius DT42 of the surface of the fourth lens near the exit side satisfy the following relationship: 0.6 <DT42 / DT11<1。

[0018] Furthermore, the sum of the edge thicknesses ∑ET of the first to fourth lenses on the optical axis and the sum of the center thicknesses ∑CT of the first to fourth lenses on the optical axis satisfy the following condition: 0.8 < ∑ET / ∑CT < 0.9.

[0019] Furthermore, the edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis satisfy the following condition: 0.8≤ET2 / ET1≤1.2.

[0020] Further, the edge thickness ET2 of the second lens on the optical axis and the central thickness CT2 of the second lens on the optical axis satisfy: 1 < ET2 / CT2 < 2.

[0021] Further, the maximum central thickness CT on the optical axis among the first lens to the fourth lens

[0028] ,

[0027] , ,

[0026] , ,

[0025] , ,

[0024] , and the minimum central thickness CT on the optical axis among the first lens to the fourth lens MIN satisfy: 2 < CT MAX / CT MIN < 5.

[0022] According to another aspect of the present invention, an optical lens group is provided, which sequentially includes along the optical axis from the light incident side to the light exit side: a first lens, the surface near the incident side is a convex surface, and the surface near the exit side is a convex surface; an aperture stop; a second lens; a third lens; a fourth lens; wherein, the on-axis distance BFL from the surface near the exit side of the fourth lens to the imaging surface and the effective focal length f of the optical lens group satisfy: 0.6 < BFL / f < 0.8; the on-axis distance BFL from the surface near the exit side of the fourth lens to the imaging surface and the on-axis distance TTL from the surface near the incident side of the first lens to the imaging surface satisfy: 0.5 < BFL / TTL < 0.7.

[0023] Further, the distance SD on the optical axis from the aperture stop to the surface near the exit side of the fourth lens and the distance TD on the optical axis from the surface near the incident side of the first lens to the surface near the exit side of the fourth lens satisfy: 0.5 < SD / TD < 0.8.

[0024] Further, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface near the incident side of the first lens to the imaging surface satisfy: 0.9 < f / TTL < 1; the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy: 0.3 < f1 / f < 0.6.

[0025] Further, the effective focal length f1 of the first lens and the radius of curvature R1 of the surface near the incident side of the first lens satisfy: 0.5 < R1 / f1 < 1.

[0026] Further, the air gap T23 on the optical axis between the second lens and the third lens and the sum ∑AT of the air gaps on the optical axis between adjacent two lenses among the first lens to the fourth lens satisfy: 0.5 < T23 / ∑AT < 1.

[0027] Further, the central thickness CT2 of the second lens on the optical axis and the central thickness CT3 of the third lens on the optical axis satisfy: 0.5 < CT2 / CT3 < 1.1.

[0028] Further, the central thickness CT1 of the first lens on the optical axis satisfies 0.35 < CT1 / ∑CT < 0.5 with the sum ∑CT of the central thicknesses of the first lens to the fourth lens on the optical axis.

[0029] Further, the Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy 0.4 < V2 / V1 < 0.5.

[0030] Further, the refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy 0.8 < N3 / N2 < 1.1.

[0031] Further, the maximum effective radius DT11 of the surface of the first lens near the incident side and the maximum effective radius DT42 of the surface of the fourth lens near the exit side satisfy 0.6 < DT42 / DT11 < 1.

[0032] Further, the sum ∑ET of the edge thicknesses of the first lens to the fourth lens on the optical axis satisfies 0.8 < ∑ET / ∑CT < 0.9 with the sum ∑CT of the central thicknesses of the first lens to the fourth lens on the optical axis.

[0033] Further, the edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis satisfy 0.8 ≤ ET2 / ET1 ≤ 1.2.

[0034] Further, the edge thickness ET2 of the second lens on the optical axis and the central thickness CT2 of the second lens on the optical axis satisfy 1 < ET2 / CT2 < 2.

[0035] Further, the maximum central thickness CT MAX among the first lens to the fourth lens on the optical axis and the minimum central thickness CT MIN among the first lens to the fourth lens on the optical axis satisfy 2 < CT MAX / CT MIN < 5.

[0036] Applying the technical solution of the present invention, the optical lens group sequentially includes a first lens, an aperture stop, a second lens, a third lens, and a fourth lens along the optical axis from the light incident side to the light exit side; the surface of the first lens near the incident side is a convex surface, and the surface near the exit side is a convex surface; wherein, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface satisfy 0.9 < f / TTL < 1; the on-axis distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the effective focal length f of the optical lens group satisfy 0.6 < BFL / f < 0.8.

[0037] By properly controlling the surface shape of the lenses, aberrations in the optical lens group can be effectively eliminated, improving the quality of light captured by the optical lens group. By reasonably constraining the ratio between the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging plane, and the ratio between the on-axis distance BFL from the surface of the fourth lens near the exit side to the imaging plane and the effective focal length f of the optical lens group, the user's ultra-long-distance shooting needs can be met. Simultaneously, in conjunction with module requirements, stray light at the tail end can be reduced, ensuring image quality.

[0038] Furthermore, the optical lens group of this application can be fitted with a prism to function as a periscope telephoto lens. Compared to similar telephoto lenses on the market, it has a larger aperture, thus ensuring not only clear imaging of distant objects during actual shooting but also sufficient light entering the optical system in night shooting, reducing image noise and resulting in excellent image quality in low-light conditions. Attached Figure Description

[0039] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0040] Figure 1 A schematic diagram of the optical lens assembly of Example 1 of the present invention is shown;

[0041] Figures 2 to 5 They are shown respectively Figure 1 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group in the image;

[0042] Figure 6 A schematic diagram of the optical lens assembly of Example 2 of the present invention is shown;

[0043] Figures 7 to 10 They are shown respectively Figure 6 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group in the image;

[0044] Figure 11 A schematic diagram of the optical lens assembly of Example 3 of the present invention is shown;

[0045] Figures 12 to 15 They are shown respectively Figure 11 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group in the image;

[0046] Figure 16 A schematic diagram of the optical lens assembly of Example 4 of the present invention is shown;

[0047] Figures 17 to 20They are shown respectively Figure 16 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group in the image;

[0048] Figure 21 A schematic diagram of the optical lens assembly of Example 5 of the present invention is shown;

[0049] Figures 22 to 25 They are shown respectively Figure 21 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group in the image;

[0050] Figure 26 A schematic diagram of the optical lens assembly of Example Six of the present invention is shown;

[0051] Figures 27 to 30 They are shown respectively Figure 26 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group in the image;

[0052] Figure 31 A schematic diagram of the optical lens assembly of Example Seven of the present invention is shown;

[0053] Figures 32 to 35 They are shown respectively Figure 31 The on-axis chromatic aberration curve, magnification chromatic aberration curve, astigmatism curve, and distortion curve of the optical lens group.

[0054] The above figures include the following reference numerals:

[0055] E1, First lens; S1, Surface of the first lens near the incident side; S2, Surface of the first lens near the exit side; STO, Aperture stop; E2, Second lens; S3, Surface of the second lens near the incident side; S4, Surface of the second lens near the exit side; E3, Third lens; S5, Surface of the third lens near the incident side; S6, Surface of the third lens near the exit side; E4, Fourth lens; S7, Surface of the fourth lens near the incident side; S8, Surface of the fourth lens near the exit side; E5, Filter; S9, Surface of the filter near the incident side; S10, Surface of the filter near the exit side; S11, Imaging plane. Detailed Implementation

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0057] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0058] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0059] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second or third lens.

[0060] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0061] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the light incident side is called the incident side surface of the lens, and the surface of each lens closest to the light emitting side is called the emitting side surface of the lens. The surface shape in the paraxial region can be determined according to the judgment method commonly known in the field, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens database of optical software) to determine concavity and convexity. For the surface closest to the incident side, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the surface closest to the emitting side, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0062] To address the problem that existing optical lens assemblies cannot simultaneously achieve telephoto capabilities, large aperture, and high image quality, this invention provides an optical lens assembly.

[0063] Example 1

[0064] like Figures 1 to 35As shown, the optical lens group includes a first lens, an aperture stop, a second lens, a third lens, and a fourth lens in sequence along the optical axis from the light incident side to the light exit side; the surface of the first lens near the incident side is convex, and the surface near the exit side is convex; wherein, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface satisfy: 0.9 < f / TTL < 1; the on-axis distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the effective focal length f of the optical lens group satisfy: 0.6 < BFL / f < 0.8.

[0065] By reasonably controlling the surface shape of the lenses, the aberration of the optical lens group can be effectively eliminated, and the quality of capturing light by the optical lens group can be improved. By reasonably restricting the ratio between the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface, and the ratio between the on-axis distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the effective focal length f of the optical lens group, the user's ultra-long-distance shooting requirements can be met. At the same time, in cooperation with the requirements of the module end, the stray light at the tail end can be improved, and the imaging quality can be guaranteed.

[0066] In addition, a prism can be added to the optical lens group of the present application to form a periscope telephoto lens. Compared with similar telephoto lenses on the market, the aperture is larger. Therefore, during actual shooting, it can not only maintain a clear imaging ability for distant objects, but also ensure that sufficient imaging light enters the optical system during night shooting, reducing the noise of the imaging picture, so that in a dark scene environment, the taken photos can have a good imaging effect.

[0067] In this embodiment, the on-axis distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface satisfy: 0.5 < BFL / TTL < 0.7. By reasonably restricting the ratio between the on-axis distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface, on the one hand, the rear focus requirement of the optical lens group is met, and on the other hand, the unnecessary stray light caused by the tail end of the lens barrel is effectively reduced.

[0068] In this embodiment, the distance SD on the optical axis from the aperture stop to the surface of the fourth lens near the exit side and the distance TD on the optical axis from the surface of the first lens near the incident side to the surface of the fourth lens near the exit side satisfy: 0.5 < SD / TD < 0.8. By restricting the ratio between the distance SD on the optical axis from the aperture stop to the surface of the fourth lens near the exit side and the distance TD on the optical axis from the surface of the first lens near the incident side to the surface of the fourth lens near the exit side, the air gap between the last three optical lenses can be restricted, which not only reduces the number of thick spacers used in the optical lens group, but also reduces the contact area between light and the spacers, effectively reducing the stray light caused by the thick spacers and improving the imaging quality

[0069] In this embodiment, the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy: 0.3 < f1 / f < 0.6. Meeting this conditional formula can not only slow down the deflection of light in the first lens, avoid excessive optical power of the first lens, thereby reducing the sensitivity of the first lens and avoiding overly strict tolerance requirements, but also reduce the spherical aberration generated by the first lens.

[0070] In this embodiment, the effective focal length f1 of the first lens and the radius of curvature R1 of the surface of the first lens close to the incident side satisfy: 0.5 < R1 / f1 < 1. Meeting this conditional formula can effectively control the shape of the first lens, improve the processability, and at the same time significantly improve the ghost image.

[0071] In this embodiment, the air gap T23 between the second lens and the third lens on the optical axis and the sum ∑AT of the air gaps between adjacent lenses among the first lens to the fourth lens on the optical axis satisfy: 0.5 < T23 / ∑AT < 1. Meeting this conditional formula can effectively reduce the size of the spacer in the optical lens group, reduce the contact area between light and the spacer, thereby reducing the stray light influence brought by the spacer and ensuring the imaging quality.

[0072] In this embodiment, the central thickness CT2 of the second lens on the optical axis and the central thickness CT3 of the third lens on the optical axis satisfy: 0.5 < CT2 / CT3 < 1.1. Such a setting is for the uniformity of the lens thickness on the one hand, reducing the processing difficulty, and on the other hand improving the ghost image reflected between the second lens and the third lens.

[0073] In this embodiment, the central thickness CT1 of the first lens on the optical axis and the sum ∑CT of the central thicknesses of the first lens to the fourth lens on the optical axis satisfy: 0.35 < CT1 / ∑CT < 0.5. Meeting this conditional formula can avoid the situation where the central thickness of the first lens on the optical axis is too large or too small, resulting in an increase in the process processing difficulty.

[0074] In this embodiment, the Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy: 0.4 < V2 / V1 < 0.5. Meeting this conditional formula is beneficial to balancing the chromatic aberration generated by the first lens and the second lens.

[0075] In this embodiment, the refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy: 0.8 < N3 / N2 < 1.1. Meeting this conditional formula can effectively control the light propagation trend, improve the light collection ability of the optical lens group, improve the illuminance, and effectively reduce the sensitivity of the lens.

[0076] In this embodiment, the following condition is satisfied between the maximum effective radius DT11 of the surface of the first lens near the incident side and the maximum effective radius DT42 of the surface of the fourth lens near the exit side: 0.6 < DT42 / DT11 < 1. Meeting this conditional expression can, on the one hand, reduce the size of the tail end of the lens barrel and reserve space for the motor on the premise of having little impact on the performance of the optical lens group; on the other hand, ensure the stability of the assembly process.

[0077] In this embodiment, the following condition is satisfied between the sum ∑ET of the edge thicknesses of the first lens to the fourth lens on the optical axis and the sum ∑CT of the central thicknesses of the first lens to the fourth lens on the optical axis: 0.8 < ∑ET / ∑CT < 0.9. Meeting this conditional expression can, on the one hand, ensure the uniformity of each lens in the optical lens group and reduce the process difficulty; on the other hand, effectively improve stray light and ghost images.

[0078] In this embodiment, the following condition is satisfied between the edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis: 0.8 ≤ ET2 / ET1 ≤ 1.2. Meeting this conditional expression can, on the one hand, be beneficial to the improvement of stray light and ghost images; on the other hand, provide feasibility for process processing.

[0079] In this embodiment, the following condition is satisfied between the edge thickness ET2 of the second lens on the optical axis and the central thickness CT2 of the second lens on the optical axis: 1 < ET2 / CT2 < 2. Meeting this conditional expression can, on the one hand, ensure that the second lens does not appear in a state of being too thick or too thin, resulting in a situation where it cannot be processed in terms of technology; on the other hand, improve the ghost images of the second lens. Preferably, 1.2 < ET2 / CT2 < 1.8.

[0080] In this embodiment, the maximum central thickness CT on the optical axis among the first lens to the fourth lens MAX and the minimum central thickness CT on the optical axis among the first lens to the fourth lens MIN satisfy the following: 2 < CT MAX / CT MIN < 5. Meeting this conditional expression is beneficial to ensuring the stability of the optical lens group. Preferably, 2.1 < CT MAX / CT MIN < 4.2.

[0081] Embodiment Two

[0082] As Figures 1 to 35As shown, the optical lens group sequentially includes a first lens, an aperture stop, a second lens, a third lens, and a fourth lens along the optical axis from the light incident side to the light exit side; the surface of the first lens close to the incident side is convex, and the surface of the first lens close to the exit side is convex; wherein, the axial distance BFL from the surface of the fourth lens close to the exit side to the imaging surface and the effective focal length f of the optical lens group satisfy: 0.6 < BFL / f < 0.8; the axial distance BFL from the surface of the fourth lens close to the exit side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface satisfy: 0.5 < BFL / TTL < 0.7.

[0083] By reasonably controlling the surface shape of the lenses, the aberration of the optical lens group can be effectively eliminated, and the quality of capturing light by the optical lens group can be improved. By reasonably restricting the ratio between the axial distance BFL from the surface of the fourth lens close to the exit side to the imaging surface and the effective focal length f of the optical lens group, the user's ultra-long-distance shooting requirements can be met. At the same time, in cooperation with the requirements of the module end, the stray light at the tail end can be improved, and the imaging quality can be guaranteed. By reasonably restricting the ratio between the axial distance BFL from the surface of the fourth lens close to the exit side to the imaging surface and the axial distance TTL from the surface of the first lens close to the incident side to the imaging surface, on the one hand, the requirements for the back focal length of the optical lens group are met, and on the other hand, the unnecessary stray light caused by the tail end of the lens barrel can be effectively reduced.

[0084] In addition, a prism can be added to the optical lens group of the present application to form a periscope telephoto lens. Compared with similar telephoto lenses on the market, the aperture is larger. Therefore, during actual shooting, it can not only maintain a clear imaging ability for distant objects, but also ensure that sufficient imaging light enters the optical system during night shooting, reducing the noise of the imaging picture, so that in a dark scene environment, the taken photos can have a good imaging effect.

[0085] In this embodiment, the distance SD on the optical axis from the aperture stop to the surface of the fourth lens close to the exit side and the distance TD on the optical axis from the surface of the first lens close to the incident side to the surface of the fourth lens close to the exit side satisfy: 0.5 < SD / TD < 0.8. By restricting the ratio between the distance SD on the optical axis from the aperture stop to the surface of the fourth lens close to the exit side and the distance TD on the optical axis from the surface of the first lens close to the incident side to the surface of the fourth lens close to the exit side, the air gaps between the last three optical lenses can be restricted, which not only reduces the number of thick spacers used in the optical lens group, but also reduces the contact area between light and the spacers, effectively reducing the stray light caused by the thick spacers and improving the imaging quality.

[0086] In this embodiment, the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface satisfy: 0.9 < f / TTL < 1. By reasonably restricting the ratio between the effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface, the user's ultra-long-distance shooting requirements can be met. At the same time, in coordination with the requirements of the module end, the stray light at the tail end can be improved, and the imaging quality can be guaranteed.

[0087] In this embodiment, the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy: 0.3 < f1 / f < 0.6. Meeting this conditional formula can not only slow down the refraction of light in the first lens, avoid excessive optical power of the first lens, thereby reducing the sensitivity of the first lens and avoiding overly strict tolerance requirements, but also reduce the spherical aberration generated by the first lens.

[0088] In this embodiment, the effective focal length f1 of the first lens and the radius of curvature R1 of the surface of the first lens near the incident side satisfy: 0.5 < R1 / f1 < 1. Meeting this conditional formula can effectively control the shape of the first lens, improve the processability, and at the same time significantly improve the ghost image.

[0089] In this embodiment, the air gap T23 between the second lens and the third lens on the optical axis and the sum ∑AT of the air gaps between adjacent two lenses among the first lens to the fourth lens on the optical axis satisfy: 0.5 < T23 / ∑AT < 1. Meeting this conditional formula can effectively reduce the size of the spacer in the optical lens group, reduce the contact area between the light and the spacer, thereby reducing the influence of stray light brought by the spacer and guaranteeing the imaging quality.

[0090] In this embodiment, the central thickness CT2 of the second lens on the optical axis and the central thickness CT3 of the third lens on the optical axis satisfy: 0.5 < CT2 / CT3 < 1.1. Such a setting is一方面 for the uniformity of the lens thickness, reducing the processing difficulty, and另一方面 improving the ghost image reflected between the second lens and the third lens.

[0091] In this embodiment, the central thickness CT1 of the first lens on the optical axis and the sum ∑CT of the central thicknesses of the first lens to the fourth lens on the optical axis satisfy:​​​​​In this embodiment, the refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy: 0.8 < N3 / N2 < 1.1. Satisfying this conditional formula can effectively control the light propagation trend, improve the light collection ability of the optical lens group, improve the illuminance, and effectively reduce the sensitivity of the lens.

[0094] In this embodiment, the maximum effective radius DT11 of the surface of the first lens near the incident side and the maximum effective radius DT42 of the surface of the fourth lens near the exit side satisfy: 0.6 < DT42 / DT11 < 1. Satisfying this conditional formula can, on the premise of having little impact on the performance of the optical lens group, on the one hand, reduce the size of the tail end of the lens barrel and reserve space for the motor; on the other hand, ensure the stability of the assembly process.

[0095] In this embodiment, the sum ∑ET of the edge thicknesses of the first lens to the fourth lens on the optical axis and the sum ∑CT of the central thicknesses of the first lens to the fourth lens on the optical axis satisfy: 0.8 < ∑ET / ∑CT < 0.9. Satisfying this conditional formula can, on the one hand, ensure the uniformity of each lens in the optical lens group and reduce the process difficulty; on the other hand, effectively improve stray light and ghost images.

[0096] In this embodiment, the edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis satisfy: 0.8 ≤ ET2 / ET1 ≤ 1.2. Satisfying this conditional formula can, on the one hand, be beneficial to the improvement of stray light and ghost images; on the other hand, provide feasibility for process processing.

[0097] In this embodiment, the edge thickness ET2 of the second lens on the optical axis and the central thickness CT2 of the second lens on the optical axis satisfy: 1 < ET2 / CT2 < 2. Satisfying this conditional formula can, on the one hand, ensure that the second lens does not have a state of being too thick or too thin, resulting in a situation where it cannot be processed in the process; on the other hand, improve the ghost image of the second lens. Preferably, 1.2 < ET2 / CT2 < 1.8.

[0098] In this embodiment, the maximum central thickness CT on the optical axis of the first lens to the fourth lens MAX and the minimum central thickness CT on the optical axis of the first lens to the fourth lens MIN satisfy: 2 < CT MAX / CT MIN < 5. Satisfying this conditional formula is beneficial to ensuring the stability of the optical lens group. Preferably, 2.1 < CT MAX / CT MIN < 4.2.

[0099] Optionally, the above optical lens group may further include a filter for correcting color deviation or a protective glass for protecting the photosensitive element located on the imaging surface.

[0100] The optical lens assembly in this application can employ multiple lenses, such as the four lenses mentioned above. By rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis distance between each lens, the sensitivity of the lens can be reduced and the lens's manufacturability improved. This makes the optical lens assembly more suitable for manufacturing and processing, and applicable to portable electronic devices such as smartphones. The left side is the light incident side, and the right side is the light exit side.

[0101] In this application, at least one of the lens surfaces is an aspherical lens. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike spherical lenses, which have a constant curvature from their center to their periphery, aspherical lenses possess superior curvature radius characteristics, offering advantages in improving distortion and astigmatism. By employing aspherical lenses, aberrations occurring during image formation can be eliminated as much as possible, thereby improving image quality.

[0102] However, those skilled in the art will understand that the number of lenses constituting the optical lens group can be changed without departing from the technical solutions claimed in this application to obtain the various results and advantages described in this specification. For example, although four lenses are described as an example in the embodiments, the optical lens group is not limited to including four lenses. If necessary, the optical lens group may also include other numbers of lenses.

[0103] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters of optical lens assemblies applicable to the above embodiments.

[0104] It should be noted that any of the examples one through seven below are applicable to all embodiments of this application.

[0105] Example 1

[0106] like Figures 1 to 5 As shown, an optical lens group of Example 1 of this application is described. Figure 1 A schematic diagram of the optical lens group structure of Example 1 is shown.

[0107] like Figure 1 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0108] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is convex, and its surface S4, near the exit side, is concave. The third lens E3 has positive optical power. Its surface S5, near the incident side, is concave, and its surface S6, near the exit side, is convex. The fourth lens E4 has positive optical power. Its surface S7, near the incident side, is convex, and its surface S8, near the exit side, is concave. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0109] In this example, the effective focal length f of the optical lens group is 17.41 mm, the optical back focal length BFL of the optical lens group is 11.64 mm, and the total system length TTL of the optical lens group is 18.64 mm.

[0110] Table 1 shows the basic structural parameters of the optical lens group in Example 1, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0111]

[0112] Table 1

[0113] In Example 1, the surfaces of any one of the first lens E1 to the fourth lens E4 that are near the incident side and near the exit side are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0114]

[0115] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 that can be used for the aspherical mirrors S1-S8 in Example 1.

[0116] Face number A4 A6 A8 A10 A12 A14 A16 S1 -2.9758E-04 4.9752E-05 -4.5661E-05 1.6119E-05 -3.1805E-06 3.3497E-07 -1.4430E-08 S2 3.3412E-03 -1.0952E-03 3.9242E-04 -9.3338E-05 1.2928E-05 -8.9307E-07 2.0172E-08 S3 -4.5680E-03 -6.0091E-04 2.9237E-04 -2.9838E-05 -1.1731E-05 3.4353E-06 -2.7497E-07 S4 -1.2774E-02 -1.3143E-04 -3.1861E-05 1.0616E-04 -8.0154E-05 1.9027E-05 -1.7292E-06 S5 2.7172E-02 -6.7446E-03 4.1425E-03 -1.5206E-03 2.8011E-04 -1.9668E-05 -1.9503E-07 S6 8.3964E-03 4.1010E-03 -2.9559E-04 -3.9392E-04 1.1433E-04 -1.0022E-05 1.5694E-07 S7 -2.4074E-02 7.3976E-03 -7.8259E-04 -4.4918E-04 1.6324E-04 -2.0072E-05 8.6723E-07 S8 -1.8344E-02 2.8676E-03 2.0416E-04 -3.1525E-04 8.0744E-05 -8.9789E-06 3.8446E-07

[0117] Table 2

[0118] Figure 2 The on-axis chromatic aberration curve of an optical lens group in Example 1 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical lens group. Figure 3The magnification chromatic aberration curve of the optical lens group in Example 1 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 4 The astigmatism curves of the optical lens group in Example 1 are shown, representing the meridional image plane curvature and the sagittal image plane curvature. Figure 5 The distortion curves of the optical lens group in Example 1 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0119] according to Figures 2 to 5 As can be seen, the optical lens group given in Example 1 can achieve good imaging quality.

[0120] Example 2

[0121] like Figures 6 to 10 The image shows an optical lens assembly of Example 2 of this application. For the sake of brevity, descriptions similar to those in Example 1 will be omitted in this example and the following examples. Figure 6 A schematic diagram of the optical lens group structure of Example 2 is shown.

[0122] like Figure 6 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0123] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is convex, and its surface S4, near the exit side, is concave. The third lens E3 has positive optical power. Its surface S5, near the incident side, is concave, and its surface S6, near the exit side, is convex. The fourth lens E4 has positive optical power. Its surface S7, near the incident side, is concave, and its surface S8, near the exit side, is convex. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0124] In this example, the effective focal length f of the optical lens group is 17.41 mm, the optical back focal length BFL of the optical lens group is 11.70 mm, and the total system length TTL of the optical lens group is 18.20 mm.

[0125] Table 3 shows the basic structural parameters of the optical lens group in Example 2, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0126]

[0127] Table 3

[0128] Table 4 shows the higher-order coefficients that can be used for each aspherical mirror in Example 2, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0129] Face number A4 A6 A8 A10 A12 A14 A16 S1 2.6386E-05 1.8180E-06 -9.7200E-06 5.6677E-07 2.0288E-07 -3.7927E-08 1.7720E-09 S2 5.4567E-03 -2.2177E-03 5.8072E-04 -9.0825E-05 8.0627E-06 -3.7251E-07 6.9405E-09 S3 -3.1155E-03 -6.5222E-04 -1.5847E-04 1.7438E-04 -4.9217E-05 6.3029E-06 -3.2084E-07 S4 -1.2706E-02 1.6119E-03 -1.4598E-03 7.3004E-04 -2.3683E-04 4.1522E-05 -3.3057E-06 S5 1.5115E-02 -1.3786E-03 5.5938E-04 6.3328E-05 -1.5225E-04 4.8219E-05 -5.0287E-06 S6 5.1885E-03 1.6480E-03 5.9930E-04 -5.5924E-04 1.2889E-04 -9.9572E-06 6.6049E-08 S7 -1.3113E-02 1.8930E-03 1.0351E-03 -8.3125E-04 2.1301E-04 -2.3720E-05 9.8137E-07 S8 -9.4437E-03 3.3307E-04 5.2214E-04 -2.6608E-04 5.6506E-05 -5.7457E-06 2.3284E-07

[0130] Table 4

[0131] Figure 7 The on-axis chromatic aberration curve of the optical lens group in Example 2 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical lens group. Figure 8 The magnification chromatic aberration curve of the optical lens group in Example 2 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 9 The astigmatism curves of the optical lens group in Example 2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 10 The distortion curves of the optical lens group in Example 2 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0132] according to Figures 7 to 10 As can be seen, the optical lens group given in Example 2 can achieve good imaging quality.

[0133] Example 3

[0134] like Figures 11 to 15 As shown, an optical lens group of Example 3 of this application is described. Figure 11 A schematic diagram of the optical lens group structure of Example 3 is shown.

[0135] like Figure 11 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0136] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is convex, and its surface S4, near the exit side, is concave. The third lens E3 has positive optical power. Its surface S5, near the incident side, is concave, and its surface S6, near the exit side, is convex. The fourth lens E4 has positive optical power. Its surface S7, near the incident side, is concave, and its surface S8, near the exit side, is convex. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0137] In this example, the effective focal length f of the optical lens group is 17.41 mm, the optical back focal length BFL of the optical lens group is 11.11 mm, and the total system length TTL of the optical lens group is 18.21 mm.

[0138] Table 5 shows the basic structural parameters of the optical lens group in Example 3, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0139]

[0140] Table 5

[0141] Table 6 shows the higher-order coefficients that can be used for each aspherical mirror in Example 3, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0142]

[0143]

[0144] Table 6

[0145] Figure 12 The on-axis chromatic aberration curve of the optical lens group in Example 3 is shown, which indicates the deflection of the focal point of light of different wavelengths after passing through the optical lens group. Figure 13 The magnification chromatic aberration curve of the optical lens group in Example 3 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 14 The astigmatism curves of the optical lens group in Example 3 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 15 The distortion curves of the optical lens group in Example 3 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0146] according to Figures 12 to 15 As can be seen, the optical lens group given in Example 3 can achieve good imaging quality.

[0147] Example 4

[0148] like Figures 16 to 20 As shown, an optical lens group of Example 4 of this application is described. Figure 16 A schematic diagram of the optical lens group structure of Example 4 is shown.

[0149] like Figure 16 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0150] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is convex, and its surface S4, near the exit side, is concave. The third lens E3 has positive optical power. Its surface S5, near the incident side, is concave, and its surface S6, near the exit side, is convex. The fourth lens E4 has positive optical power. Its surface S7, near the incident side, is convex, and its surface S8, near the exit side, is concave. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0151] In this example, the effective focal length f of the optical lens group is 17.40 mm, the optical back focal length BFL of the optical lens group is 11.42 mm, and the total system length TTL of the optical lens group is 18.26 mm.

[0152] Table 7 shows the basic structural parameters of the optical lens group in Example 4, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0153]

[0154] Table 7

[0155] Table 8 shows the higher-order coefficients that can be used for each aspherical mirror in Example 4, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0156] Face number A4 A6 A8 A10 A12 A14 S1 -4.5317E-04 3.6560E-05 -5.0826E-05 2.2906E-05 -6.0215E-06 9.2455E-07 S2 1.7292E-03 -7.6012E-05 -1.3743E-05 1.0899E-05 -2.6564E-06 3.3801E-07 S5 3.3950E-02 5.4852E-04 -1.4209E-02 2.7398E-02 -2.9996E-02 2.1727E-02 S6 3.5892E-02 -3.2054E-02 4.0810E-02 -3.6979E-02 2.4670E-02 -1.1990E-02 S7 -5.9136E-03 -2.0759E-02 2.7615E-02 -2.2918E-02 1.3652E-02 -5.9064E-03 S8 -2.0957E-02 5.6093E-03 -3.4384E-03 2.5475E-03 -1.3751E-03 4.8780E-04 Face number A16 A18 A20 A22 A24 A26 S1 -7.6151E-08 2.6146E-09 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -1.9626E-08 3.1209E-10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -1.0768E-02 3.6651E-03 -8.4128E-04 1.2414E-04 -1.0602E-05 3.9663E-07 S6 4.1857E-03 -1.0278E-03 1.7156E-04 -1.8346E-05 1.1189E-06 -2.9035E-08 S7 1.8232E-03 -3.8854E-04 5.4008E-05 -4.3882E-06 1.5765E-07 0.0000E+00 S8 -1.1163E-04 1.5859E-05 -1.2709E-06 4.3892E-08 0.0000E+00 0.0000E+00

[0157] Table 8

[0158] Figure 17 The on-axis chromatic aberration curve of the optical lens group in Example 4 is shown, which indicates the deflection of the focal point of light of different wavelengths after passing through the optical lens group. Figure 18 The magnification chromatic aberration curve of the optical lens group in Example 4 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 19 The astigmatism curves of the optical lens group in Example 4 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 20 The distortion curves of the optical lens group in Example 4 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0159] according to Figures 17 to 20 As can be seen, the optical lens group given in Example 4 can achieve good imaging quality.

[0160] Example 5

[0161] like Figures 21 to 25 As shown, an optical lens group of Example 5 of this application is described. Figure 21 A schematic diagram of the optical lens group structure of Example 5 is shown.

[0162] like Figure 21 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0163] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is convex, and its surface S4, near the exit side, is concave. The third lens E3 has negative optical power. Its surface S5, near the incident side, is concave, and its surface S6, near the exit side, is convex. The fourth lens E4 has positive optical power. Its surface S7, near the incident side, is concave, and its surface S8, near the exit side, is convex. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0164] In this example, the effective focal length f of the optical lens group is 17.42 mm, the optical back focal length BFL of the optical lens group is 11.69 mm, and the total system length TTL of the optical lens group is 18.28 mm.

[0165] Table 9 shows the basic structural parameters of the optical lens group in Example 5, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0166]

[0167] Table 9

[0168] Table 10 shows the higher-order coefficients that can be used for each aspherical mirror in Example 5, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0169] Face number A4 A6 A8 A10 A12 A14 A16 A18 S1 1.2342E-04 -1.4137E-05 6.0268E-07 -2.3558E-06 1.7022E-07 7.5137E-08 -1.2687E-08 5.1984E-10 S2 5.2494E-03 -7.7348E-04 -4.7776E-04 2.7375E-04 -6.2839E-05 7.7179E-06 -5.0304E-07 1.3536E-08 S3 -4.5590E-03 9.6832E-04 -8.4268E-04 1.6690E-04 3.4476E-05 -1.8534E-05 2.7221E-06 -1.4266E-07 S4 -1.4688E-02 1.8293E-03 -1.3832E-04 -9.3617E-04 6.9129E-04 -2.3189E-04 3.8614E-05 -2.6755E-06 S5 1.3365E-02 -1.4095E-03 1.6380E-03 -1.2080E-03 5.9634E-04 -1.9482E-04 3.6253E-05 -2.8739E-06 S6 -1.7986E-03 7.5929E-03 -2.9228E-03 7.0930E-04 -1.1453E-04 2.7969E-06 2.8114E-06 -3.2618E-07 S7 -1.7815E-02 6.7816E-03 -2.1540E-03 4.8030E-04 -1.0394E-04 1.3715E-05 1.2258E-07 -1.2614E-07 S8 -9.1302E-03 -8.8615E-06 7.6789E-04 -3.8757E-04 9.9153E-05 -1.5662E-05 1.5425E-06 -7.1614E-08

[0170] Table 10

[0171] Figure 22 The on-axis chromatic aberration curve of the optical lens group in Example 5 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical lens group. Figure 23The magnification chromatic aberration curve of the optical lens group in Example 5 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 24 The astigmatism curves of the optical lens group in Example 5 are shown, representing the meridional image plane curvature and the sagittal image plane curvature. Figure 25 The distortion curves of the optical lens group in Example 5 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0172] according to Figures 22 to 25 As can be seen, the optical lens group given in Example 5 can achieve good imaging quality.

[0173] Example 6

[0174] like Figures 26 to 30 As shown, an optical lens group of Example Six of this application is described. Figure 26 A schematic diagram of the optical lens group structure of Example 6 is shown.

[0175] like Figure 26 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0176] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is convex, and its surface S4, near the exit side, is concave. The third lens E3 has positive optical power. Its surface S5, near the incident side, is convex, and its surface S6, near the exit side, is convex. The fourth lens E4 has positive optical power. Its surface S7, near the incident side, is concave, and its surface S8, near the exit side, is convex. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0177] In this example, the effective focal length f of the optical lens group is 17.40 mm, the optical back focal length BFL of the optical lens group is 12.24 mm, and the total system length TTL of the optical lens group is 18.40 mm.

[0178] Table 11 shows the basic structural parameters of the optical lens group in Example 6, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0179]

[0180] Table 11

[0181] Table 12 shows the higher-order coefficients that can be used for each aspherical mirror in Example 6, wherein each aspherical surface type can be defined by formula (1) given in Example 1 above.

[0182] Face number A4 A6 A8 A10 A12 S1 -6.8781E-04 3.6170E-04 -4.1285E-05 -1.6106E-05 6.9087E-06 S2 7.3567E-03 -2.0500E-03 4.6639E-04 -1.5470E-04 4.8168E-05 S3 -1.2440E-02 -1.7537E-03 3.0289E-04 0.0000E+00 0.0000E+00 S4 -3.6506E-02 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 1.0812E-02 -3.5198E-03 7.3922E-04 -1.7084E-04 5.0528E-06 S6 4.2936E-03 -2.5212E-03 2.7545E-03 -2.8847E-03 1.9647E-03 Face number A14 A16 A18 A20 A22 S1 -1.1834E-06 9.9163E-08 -3.1586E-09 0.0000E+00 0.0000E+00 S2 -9.4552E-06 1.0253E-06 -4.5679E-08 0.0000E+00 0.0000E+00 S3 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 2.7389E-06 -2.6225E-07 0.0000E+00 0.0000E+00 0.0000E+00 S6 -8.5937E-04 2.3905E-04 -4.0919E-05 3.9342E-06 -1.6275E-07

[0183] Table 12

[0184] Figure 27 The on-axis chromatic aberration curve of the optical lens group in Example Six is ​​shown, which indicates the deflection of the focal point of light of different wavelengths after passing through the optical lens group. Figure 28 The magnification chromatic aberration curve of the optical lens group in Example 6 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 29 The astigmatism curves of the optical lens group in Example Six are shown, representing the meridional image plane curvature and the sagittal image plane curvature. Figure 30 The distortion curves of the optical lens group in Example 6 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0185] according to Figures 27 to 30 As can be seen, the optical lens group given in Example 6 can achieve good imaging quality.

[0186] Example 7

[0187] like Figures 31 to 35 As shown, an optical lens group of Example Seven of this application is described. Figure 31 A schematic diagram of the optical lens group structure of Example 7 is shown.

[0188] like Figure 31 As shown, the optical lens group includes, in sequence from the light incident side to the light emitting side: first lens E1, aperture STO, second lens E2, third lens E3, fourth lens E4, filter E5, and imaging surface S11.

[0189] The first lens E1 has positive optical power. Its surface S1, near the incident side, is convex, and its surface S2, near the exit side, is convex. The second lens E2 has negative optical power. Its surface S3, near the incident side, is concave, and its surface S4, near the exit side, is concave. The third lens E3 has positive optical power. Its surface S5, near the incident side, is convex, and its surface S6, near the exit side, is convex. The fourth lens E4 has negative optical power. Its surface S7, near the incident side, is concave, and its surface S8, near the exit side, is convex. The filter E5 has a surface S9 near the incident side and a surface S10 near the exit side. Light from the object passes sequentially through surfaces S1 to S10 and is finally imaged on the imaging surface S11.

[0190] In this example, the effective focal length f of the optical lens group is 17.40 mm, the optical back focal length BFL of the optical lens group is 10.40 mm, and the total system length TTL of the optical lens group is 18.44 mm.

[0191] Table 13 shows the basic structural parameters of the optical lens group in Example 7, where the units for radius of curvature, thickness / distance, focal length, and effective radius are all millimeters (mm).

[0192]

[0193] Table 13

[0194] Table 14 shows the higher-order coefficients that can be used for each aspherical mirror in Example 7, wherein each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0195]

[0196]

[0197] Table 14

[0198] Figure 32 The on-axis chromatic aberration curve of the optical lens group in Example 7 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the optical lens group. Figure 33 The magnification chromatic aberration curve of the optical lens group in Example 7 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical lens group. Figure 34 The astigmatism curves of the optical lens group in Example 7 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 35 The distortion curves of the optical lens group in Example 7 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles.

[0199] according to Figures 32 to 35 As can be seen, the optical lens group given in Example 7 can achieve good imaging quality.

[0200] In summary, Examples 1 through 7 satisfy the relationships shown in Table 15.

[0201] Conditional / Example 1 2 3 4 5 6 7 f / TTL 0.93 0.96 0.96 0.95 0.95 0.95 0.94 BFL / f 0.67 0.67 0.64 0.66 0.67 0.70 0.60 BFL / TTL 0.62 0.64 0.61 0.63 0.64 0.66 0.56 SD / TD 0.72 0.71 0.75 0.68 0.71 0.68 0.58 f1 / f 0.46 0.43 0.46 0.39 0.43 0.36 0.50 R1 / f1 0.77 0.67 0.65 0.72 0.67 0.91 0.57 T23 / ∑AT 0.94 0.94 0.93 0.87 0.95 0.82 0.52 CT2 / CT3 0.92 0.77 1.06 1.00 0.70 0.56 0.64 CT1 / ∑CT 0.41 0.40 0.37 0.40 0.40 0.41 0.48 V2 / V1 0.42 0.42 0.42 0.49 0.42 0.49 0.49 N3 / N2 0.94 0.94 1.00 0.88 0.94 0.88 1.07 DT42 / DT11 0.69 0.86 0.90 0.78 0.87 0.86 0.76 ∑ET / ∑CT 0.87 0.85 0.84 0.87 0.85 0.87 0.89 ET2 / ET1 0.93 1.03 1.20 1.14 0.99 1.04 0.80 ET2 / CT2 1.27 1.30 1.31 1.21 1.31 1.73 1.56 <![CDATA[CT MAX / CT MIN ]]> 2.65 2.27 2.12 2.33 2.29 2.85 4.11

[0202] Table 15

[0203] Table 16 shows the effective focal length f of the optical lens groups in Examples 1 to 7, and the effective focal lengths f1 to f4 of each lens.

[0204]

[0205]

[0206] Table 16

[0207] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical lens group described above.

[0208] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0209] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0210] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0211] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical lens assembly, characterized in that, The optical lens group comprises a total of 4 lenses with optical power, arranged sequentially along the optical axis from the light incident side to the light emitting side: The first lens has positive optical power, and its surface near the incident side is convex, and its surface near the exit side is convex. Aperture; The second lens has negative optical power, and the surface of the second lens near the exit side is concave. The third lens has a convex surface on the side near the emission point. Fourth lens; Both the third lens and the fourth lens have positive optical power, or the optical power of the third lens and the optical power of the fourth lens are opposite in sign; Wherein, the axial distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the effective focal length f of the optical lens group satisfy the following condition: 0.60≤BFL / f≤0.70; the axial distance BFL from the surface of the fourth lens near the exit side to the imaging surface and the axial distance TTL from the surface of the first lens near the incident side to the imaging surface satisfy the following condition: 0.56≤BFL / TTL≤0.66; The effective focal length f1 of the first lens and the radius of curvature R1 of the surface of the first lens near the incident side satisfy the following relationship: 0.57≤R1 / f1≤0.91; The center thickness CT1 of the first lens on the optical axis and the sum of the center thicknesses of the first lens to the fourth lens on the optical axis ∑CT satisfy the following condition: 0.37≤CT1 / ∑CT≤0.

48.

2. The optical lens assembly according to claim 1, characterized in that, The distance SD from the aperture to the surface of the fourth lens near the exit side on the optical axis and the distance TD from the surface of the first lens near the incident side to the surface of the fourth lens near the exit side on the optical axis satisfy the following condition: 0.58 ≤ SD / TD ≤ 0.

75.

3. The optical lens assembly according to claim 1, characterized in that, The effective focal length f of the optical lens group and the on-axis distance TTL from the surface of the first lens near the incident side to the imaging surface satisfy the following: 0.93≤f / TTL≤0.96; the effective focal length f of the optical lens group and the effective focal length f1 of the first lens satisfy the following: 0.36≤f1 / f≤0.

50.

4. The optical lens assembly according to claim 1, characterized in that, The air gap T23 between the second and third lenses on the optical axis and the sum of the air gaps ∑AT between adjacent lenses from the first to the fourth lens on the optical axis satisfy the following condition: 0.52≤T23 / ∑AT≤0.

95.

5. The optical lens assembly according to claim 1, characterized in that, The center thickness CT2 of the second lens on the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: 0.56≤CT2 / CT3≤1.

06.

6. The optical lens assembly according to claim 1, characterized in that, The Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy the following: 0.42≤V2 / V1≤0.

49.

7. The optical lens assembly according to claim 1, characterized in that, The refractive index N2 of the second lens and the refractive index N3 of the third lens satisfy the following condition: 0.88≤N3 / N2≤1.

07.

8. The optical lens assembly according to claim 1, characterized in that, The maximum effective radius DT11 of the surface of the first lens near the incident side and the maximum effective radius DT42 of the surface of the fourth lens near the exit side satisfy the following condition: 0.69≤DT42 / DT11≤0.

90.

9. The optical lens assembly according to claim 1, characterized in that, The sum of the edge thicknesses ∑ET of the first lens to the fourth lens on the optical axis and the sum of the center thicknesses ∑CT of the first lens to the fourth lens on the optical axis satisfy the following condition: 0.84≤∑ET / ∑CT≤0.

89.

10. The optical lens assembly according to claim 1, characterized in that, The edge thickness ET1 of the first lens on the optical axis and the edge thickness ET2 of the second lens on the optical axis satisfy the following condition: 0.80≤ET2 / ET1≤1.

20.

11. The optical lens assembly according to claim 1, characterized in that, The edge thickness ET2 of the second lens on the optical axis and the center thickness CT2 of the second lens on the optical axis satisfy the following condition: 1.21≤ET2 / CT2≤1.

73.

12. The optical lens assembly according to claim 1, characterized in that, The maximum center thickness CT of the first to the fourth lenses along the optical axis MAX The minimum center thickness CT of the first to fourth lenses on the optical axis MIN The condition is satisfied that: 2.12 ≤ CT MAX / CT MIN ≤4.11.

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