Imaging Lens and Imaging Device

Abstract

The present invention discloses an imaging lens and a camera device, wherein the imaging lens includes a first lens group with positive focal power, a second lens group with negative focal power, and a third lens group with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis. During focusing of the imaging lens, the second lens group moves along the optical axis. The first lens group includes a front lens group, a stop, and a rear lens group in sequence. The imaging lens satisfies 2.5≤|f1a / f23|≤20, where f1a is the focal length of the front lens group and f23 is the combined focal length of the second and third lens groups. The imaging lens of the present invention achieves good optical performance by arranging a rear lens group and a second lens group to reduce spherical aberration and astigmatism. By limiting the relationship between the focal length of the front lens group and the combined focal length of the second and third lens groups to satisfy 2.5≤|f1a / f23|≤20, the imaging lens achieves high-quality imaging performance while meeting the requirements of large aperture, low chromatic aberration, miniaturization, and low cost.

Description

Technical Field

[0001] The present invention belongs to the field of optical technology, and particularly relates to an imaging lens and a camera device including the imaging lens. Background Art

[0002] As a traditional camera, for a single-lens reflex camera, due to the need to avoid the reflex mirror in lens design, it must ensure a relatively long back focal length, resulting in a relatively large lens, and the design freedom will also be greatly restricted. In recent years, mirrorless cameras have developed rapidly. Since the reflex mirror is removed, the back focal length of the lens becomes shorter and the design freedom becomes higher. However, for the characteristics of mirrorless lenses such as lens miniaturization and focusing group lightweight, there are problems such as difficulty in correcting aberrations in design, low performance, and high sensitivity leading to manufacturing difficulties. Summary of the Invention

[0003] In view of this, in order to overcome the defects in the prior art, the purpose of the present invention is to provide an imaging lens that has high imaging performance while having a large aperture, low chromatic aberration, and miniaturization.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] An imaging lens includes a first lens group with positive optical power, a second lens group with negative optical power, and a third lens group with positive optical power, which are sequentially arranged along the optical axis from the object side to the image side; during the focusing process of the imaging lens, the second lens group moves along the optical axis direction; the first lens group sequentially includes a front lens group, a diaphragm, and a rear lens group;

[0006] The imaging lens satisfies the following conditional formula:

[0007] 2.5 ≤ |f1a / f23| ≤ 20 (1)

[0008] Wherein, f1a is the focal length of the front lens group; f23 is the combined focal length of the second lens group and the third lens group.

[0009] When the lower limit value of the conditional formula (1) is exceeded, the optical power of f23 is relatively weak, and it is difficult for the exit pupil to move towards the object side, resulting in a relatively large light emission angle; when the upper limit of the conditional formula (1) is exceeded, the optical power of f1a also becomes very weak, and the back focal length will also become longer, which is not conducive to the miniaturization of the lens. Through the above lens structure and conditional limitations, the imaging lens satisfies the requirements of a large aperture, low chromatic aberration, miniaturization, and low cost, while also having high-quality imaging performance.

[0010] According to some preferred embodiments of the present invention, the first lens group satisfies the following conditional formula:

[0011] 1.1 < f / f1 < 1.5 (2)

[0012] Wherein, f1 is the focal length of the first lens group; f is the focal length of the imaging lens.

[0013] When the conditional formula (2) exceeds the lower limit value, the optical power of the first lens group becomes weaker, and the influence of the lens group from the second lens group to the imaging surface on the optical performance becomes smaller, so that the aberration changes are smaller during focusing, and the optical performance can be well maintained. However, this will cause the movement amount of the focusing group (the second lens group) to become larger, and further make it difficult to achieve the miniaturization of the optical system of the lens and fast focusing; when the conditional formula (2) exceeds the upper limit, the combined magnification of the second lens group and the third lens group becomes larger, and the movement amount of the focusing group (the second lens group) becomes smaller, which is beneficial to the miniaturization of the lens. However, the correction of spherical aberration and astigmatism will become difficult.

[0014] According to some preferred embodiments of the present invention, the second lens group satisfies the following conditional formula:

[0015] -1.8 < f / f2 < -0.6 (3)

[0016] Wherein, f2 is the focal length of the second lens group; f is the focal length of the imaging lens.

[0017] The conditional formula (3) limits the suitable focal length range of the second lens group, and within this range, it has good effects on controlling the length of the lens and controlling the aberration changes. When the conditional formula (3) exceeds the lower limit value, the optical power of the second lens group becomes stronger, which brings certain advantages to the miniaturization of the lens. However, at the same time, spherical aberration, coma aberration, especially when focusing at a short distance, will be more difficult to correct. When the conditional formula (3) exceeds the upper limit, the optical power of the second lens group becomes weaker, and various aberrations, especially the Petzval sum, become larger, resulting in more difficult correction of astigmatism and chromatic aberration distortion. At the same time, it is also more difficult to achieve the miniaturization of the lens.

[0018] According to some preferred embodiments of the present invention, the third lens group satisfies the following conditional formula:

[0019] 0.5 < f / f3 < 1.4 (4)

[0020] Wherein, f3 is the focal length of the third lens group; f is the focal length of the imaging lens.

[0021] Conditional expression (4) restricts the appropriate focal length range of the third lens group. Within this range, it also contributes to compensating for aberration variations during focusing of the lens and reducing the moving distance of the second lens group (focusing group). At the same time, it also provides good correction for chromatic aberration and Petzval sum. When conditional expression (4) exceeds the lower limit value, the optical power of the third lens group is weak, the back focal length will become longer, and it will be difficult to miniaturize the lens. At the same time, it will result in insufficient correction of chromatic aberration and Petzval sum. When conditional expression (4) exceeds the upper limit, the optical power of the third lens group is strong, the back focal length will become shorter, and it may not be usable for some cameras.

[0022] According to some preferred implementation aspects of the present invention, the imaging lens satisfies the following conditional expression:

[0023] 1 < (TL - BF) / f < 3.5 (5)

[0024] Wherein, TL is the overall length of the imaging lens; BF is the distance between the lens surface closest to the image side in the imaging lens and the image plane; f is the focal length of the imaging lens.

[0025] Conditional expression (5) is used to regulate the size of the lens, ensuring the back focal length of the lens and a reasonable exit pupil position. When conditional expression (5) exceeds the lower limit value, the lens is short, and it is difficult to correct astigmatism, coma, and lateral chromatic aberration; when conditional expression (5) exceeds the upper limit, the lens may have insufficient back focal length and cannot meet the use requirements of specific cameras.

[0026] According to some preferred implementation aspects of the present invention, the front lens group sequentially includes a first positive lens, a second negative lens, a third negative lens, and a fourth positive lens, and the rear lens group includes an aspherical lens with positive optical power.

[0027] According to some preferred implementation aspects of the present invention, the second lens group includes an aspherical lens with negative optical power.

[0028] Due to the large aperture of the imaging lens, during the focusing process of the second lens group from infinity to the closest shooting distance, the changes in spherical aberration and astigmatism are very large. Therefore, an aspherical lens with positive optical power is arranged on the image side of the first lens group, that is, the rear lens group, and an aspherical lens with negative optical power is arranged in the second lens group to reduce spherical aberration and astigmatism and achieve good optical performance. The material of the aspherical lens is not limited and can be glass or high molecular plastic.

[0029] According to some preferred implementation aspects of the present invention, the aspherical lens satisfies the following conditional expression:

[0030] z = CY 2 / [1 + {1 - (1 + k)c 2 Y 2} 1 / 2 + A4Y 4+A6Y 6 +A8Y 8 +A10Y 10

[0031] Wherein, z is the aspherical depth; C is the paraxial curvature (1 / r); Y is the height from the optical axis to the lens; k is the eccentricity; A4 is the 4th-order aspherical coefficient; A6 is the 6th-order aspherical coefficient; A8 is the 8th-order aspherical coefficient; A10 is the 10th-order aspherical coefficient.

[0032] The present invention also provides a camera device including the imaging lens as described above.

[0033] According to some preferred embodiments of the present invention, the camera device further includes an imaging element for outputting a camera signal corresponding to the optical image formed by the imaging lens.

[0034] Due to the implementation of the above technical solutions, the imaging lens of the present invention has the following advantages compared with the prior art: By providing a rear lens group and a second lens group, the spherical aberration and astigmatism are reduced, achieving good optical performance; By defining that the focal length of the front lens group and the combined focal length of the second lens group and the third lens group satisfy 2.5 ≤ |f1a / f23| ≤ 20, the imaging lens satisfies large aperture, low chromatic aberration, miniaturization, and low cost, and also has high-quality imaging performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 Shows the lens structure schematic diagram of the imaging lens in Embodiment 1 of the present invention;

[0037] Figure 2A Shows the aberration schematic diagram of the imaging lens in Embodiment 1 of the present invention when focused at infinity (inf);

[0038] Figure 2B Shows the aberration schematic diagram of the imaging lens in Embodiment 1 of the present invention when focused at an intermediate distance (β = 0.025);

[0039] Figure 2C Shows the aberration schematic diagram of the imaging lens in Embodiment 1 of the present invention when focused at the closest distance;

[0040] Figure 3Shows the schematic diagram of the lens structure of the imaging lens in the second embodiment of the present invention;

[0041] Figure 4A Shows the aberration schematic diagram of the imaging lens in the second embodiment of the present invention when focused at infinity (inf);

[0042] Figure 4B Shows the aberration schematic diagram of the imaging lens in the second embodiment of the present invention when focused at an intermediate distance (β = 0.025);

[0043] Figure 4C Shows the aberration schematic diagram of the imaging lens in the second embodiment of the present invention when focused at the closest distance;

[0044] Figure 5 Shows the schematic diagram of the lens structure of the imaging lens in the third embodiment of the present invention;

[0045] Figure 6A Shows the aberration schematic diagram of the imaging lens in the third embodiment of the present invention when focused at infinity (inf);

[0046] Figure 6B Shows the aberration schematic diagram of the imaging lens in the third embodiment of the present invention when focused at an intermediate distance (β = 0.025);

[0047] Figure 6C Shows the aberration schematic diagram of the imaging lens in the third embodiment of the present invention when focused at the closest distance;

[0048] Figure 7 Shows the schematic diagram of the lens structure of the imaging lens in the fourth embodiment of the present invention;

[0049] Figure 8A Shows the aberration schematic diagram of the imaging lens in the fourth embodiment of the present invention when focused at infinity (inf);

[0050] Figure 8B Shows the aberration schematic diagram of the imaging lens in the fourth embodiment of the present invention when focused at an intermediate distance (β = 0.025);

[0051] Figure 8C Shows the aberration schematic diagram of the imaging lens in the fourth embodiment of the present invention when focused at the closest distance;

[0052] Figure 9 Shows the schematic diagram of the lens structure of the imaging lens in the fifth embodiment of the present invention;

[0053] Figure 10A Shows the aberration schematic diagram of the imaging lens in the fifth embodiment of the present invention when focused at infinity (inf);

[0054] Figure 10BIt shows the aberration schematic diagram of the imaging lens in the middle distance focusing (β = 0.025) in the fifth embodiment of the present invention;

[0055] Figure 10C It shows the aberration schematic diagram of the imaging lens in the closest distance focusing in the fifth embodiment of the present invention;

[0056] Figure 11 It shows the lens structure schematic diagram of the imaging lens in the sixth embodiment of the present invention;

[0057] Figure 12A It shows the aberration schematic diagram of the imaging lens in the infinite distance focusing (inf) in the sixth embodiment of the present invention;

[0058] Figure 12B It shows the aberration schematic diagram of the imaging lens in the middle distance focusing (β = 0.025) in the sixth embodiment of the present invention;

[0059] Figure 12C It shows the aberration schematic diagram of the imaging lens in the closest distance focusing in the sixth embodiment of the present invention;

[0060] In the above drawings: The first lens group - G1, the front lens group - G1a, the first positive lens - L11, the second negative lens - L12, the third negative lens - L13, the fourth positive lens - L14, the aperture - ST, the rear lens group - G1b, the fifth positive lens - L15, the second lens group - G2, the negative lens - L21, the third lens group - G3, the positive lens - L31, the imaging glass plate - GG. Detailed implementation manners

[0061] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0062] Hereinafter, the imaging lens of the present invention and the photographing device having the same will be described in detail based on the drawings. In the lens data, the refractive index and the focal length are the values of the d line (wavelength 587.56 nm). Among them, in the relevant data of the imaging lens, the unit of length is mm, and its unit will be omitted from showing.

[0063] In this specification, the same reference numerals are attached to the same components throughout the text. It should be noted that the symbol explanations used in the following tables and descriptions are as follows:

[0064] "No." represents the surface number; "R" is the radius of curvature; "D" is the on-axis surface distance between the i-th surface and the (i + 1)-th surface; "Nd" is the refractive index; "Vd" is the Abbe number; "FNo" is the F-number; "ω" is the semi-field angle; "f" is the focal length of the imaging lens. Regarding the surface number, "ASPH" indicates that the surface is an aspherical surface, and "STO" represents the aperture stop. In addition, regarding the on-axis surface distance, the variable distances in each table are indicated in the order of "infinity focus (inf)", "intermediate distance focus (β = 0.025)", and "closest distance focus".

[0065] The imaging lens of the present application includes a first lens group G1 with a positive optical power, a second lens group G2 with a negative optical power, a third lens group G3 with a positive optical power, and an imaging glass plate GG, which are sequentially arranged along the optical axis from the object side to the image side. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction.

[0066] The first lens group G1 sequentially includes a front lens group G1a, an aperture stop ST, and a rear lens group G1b. The front lens group G1a sequentially includes a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14. The rear lens group G1b includes an aspherical lens with a positive optical power, namely a fifth positive lens L15; the second lens group G2 includes an aspherical lens with a negative optical power, namely a negative lens L21, and the third lens group G3 includes a positive lens L31. The first positive lens L11, the second negative lens L12, the third negative lens L13, the fourth positive lens L14, the aperture stop ST, the fifth positive lens L15, the negative lens L21, and the positive lens L31 are sequentially arranged along the optical axis direction.

[0067] Due to the large aperture of the imaging lens, during the focusing process of the second lens group G2 from infinity to the closest shooting distance, the changes in spherical aberration and astigmatism are both large. Therefore, an aspherical lens with a positive optical power is arranged on the image side of the first lens group G1, that is, the rear lens group G1b, and an aspherical lens with a negative optical power is arranged in the second lens group G2 to reduce spherical aberration and astigmatism and achieve good optical performance. The material of the aspherical lens is not limited and can be glass or polymer plastic.

[0068] The aspherical lens in the present application satisfies the following conditional formula:

[0069] z = CY 2 / [1 + {1 - (1 + k)c 2 Y 2} 1 / 2 +A4Y 4 +A6Y 6 +A8Y 8 +A10Y 10

[0070] Wherein, z is the aspherical depth, the height in the direction perpendicular to the optical axis (i.e., the diameter-height); c is the paraxial curvature of the vertex of the lens, i.e., the reciprocal of the radius of curvature (1 / r); Y is the height from the optical axis to the lens, the distance from the surface vertex in the direction of the optical axis (i.e., the sag amount); k is the eccentricity, the taper constant; A4 is the 4th order aspherical coefficient; A6 is the 6th order aspherical coefficient; A8 is the 8th order aspherical coefficient; A10 is the 10th order aspherical coefficient.

[0071] The imaging lens sequence of the present application satisfies the following conditions:

[0072] 1) The imaging lens satisfies the following conditional formula:

[0073] 2.5 ≤ |f1a / f23| ≤ 20 (1)

[0074] Wherein, f1a is the focal length of the front lens group G1a; f23 is the combined focal length of the second lens group G2 and the third lens group G3.

[0075] When the lower limit value of the conditional formula (1) is exceeded, the optical power of f23 is relatively weak, and it is difficult for the exit pupil to move toward the object side, resulting in a large light emission angle; when the upper limit of the conditional formula (1) is exceeded, the optical power of f1a also becomes very weak, and the back focal length will also become longer, which is not conducive to the miniaturization of the lens. Through the above lens structure and condition limitations, the imaging lens satisfies large aperture, low chromatic aberration, miniaturization, and low cost, and also has high-quality imaging performance.

[0076] 2) The first lens group G1, the second lens group G2, and the third lens group G3 need to respectively satisfy the following conditional formulas (2), (3), and (4):

[0077] 1.1 < f / f1 < 1.5 (2)

[0078] -1.8 < f / f2 < -0.6 (3)

[0079] 0.5 < f / f3 < 1.4 (4)

[0080] Wherein, f1 is the focal length of the first lens group G1; f2 is the focal length of the second lens group G2; f3 is the focal length of the third lens group G3; f is the focal length of the imaging lens.

[0081] When the conditional formula (2) exceeds the lower limit value, the optical power of the first lens group G1 becomes weaker, and the influence of the lens group from the second lens group G2 to the imaging surface on the optical performance becomes smaller. As a result, the aberration variations during focusing are smaller, and the optical performance can be well maintained. However, this will cause the movement amount of the focusing group (the second lens group G2) to become larger, and further make it difficult to achieve miniaturization of the lens optical system and fast focusing. When the conditional formula (2) exceeds the upper limit, the combined magnification of the second lens group G2 and the third lens group G3 becomes larger, and the movement amount of the focusing group (the second lens group G2) becomes smaller, which is beneficial for the miniaturization of the lens. However, the correction of spherical aberration and astigmatism will become difficult.

[0082] The conditional formula (3) limits the appropriate focal length range of the second lens group G2, and within this range, it has good effects on controlling the length of the lens and controlling aberration variations. When the conditional formula (3) exceeds the lower limit value, the optical power of the second lens group G2 becomes stronger, which brings certain advantages to the miniaturization of the lens. However, spherical aberration, coma aberration, especially during close focusing, will be more difficult to correct. When the conditional formula (3) exceeds the upper limit, the optical power of the second lens group G2 becomes weaker, and various aberrations, especially the Petzval sum, become larger, resulting in difficulties in correcting astigmatism and chromatic aberration distortion. At the same time, it is also more difficult to achieve the miniaturization of the lens.

[0083] The conditional formula (4) limits the appropriate focal length range of the third lens group G3, and within this range, it also makes certain contributions to compensating for aberration variations during lens focusing and reducing the movement distance of the second lens group G2 (the focusing group). At the same time, it also has good compensation for chromatic aberration and the Petzval sum. When the conditional formula (4) exceeds the lower limit value, the optical power of the third lens group G3 is weaker, the back focal length will become longer, and it will be difficult to miniaturize the lens. At the same time, it will cause insufficient compensation for chromatic aberration and the Petzval sum. When the conditional formula (4) exceeds the upper limit, the optical power of the third lens group G3 is stronger, the back focal length will become shorter, and it may not be usable for some cameras.

[0084] 3) The imaging lens satisfies the following conditional formula:

[0085] 1 < (TL - BF) / f < 3.5 (5)

[0086] Wherein, TL is the overall length of the imaging lens; BF is the distance between the lens surface closest to the image side in the imaging lens and the imaging surface; f is the focal length of the imaging lens.

[0087] The conditional formula (5) is used to regulate the size of the lens, ensuring the back focal length of the lens and a reasonable exit pupil position. When the conditional formula (5) exceeds the lower limit value, the lens is shorter, and it is more difficult to correct astigmatism, coma aberration, and lateral chromatic aberration. When the conditional formula (5) exceeds the upper limit, there may be insufficient back focal length for the lens, and it cannot meet the use of specific cameras.

[0088] The present application also provides an imaging device including the above imaging lens and an imaging element, and the imaging element is used to output an imaging signal corresponding to the optical image formed by the imaging lens.

[0089] The following combines the accompanying drawings and specific numerical values to illustrate the technical effects of the imaging lens provided by the present application.

[0090] Embodiment 1

[0091] The following refers to Figure 1 、 Figures 2A - 2C to describe in detail the imaging lens involved in Embodiment 1 of the present invention.

[0092] Figure 1 is a cross-sectional view along the optical axis of the structure of the imaging lens according to Embodiment 1 of the present invention.

[0093] The imaging lens in this embodiment is configured such that the following lens groups are sequentially arranged from the Figure 1 shown object side: a first lens group G1 with a positive refractive power, a second lens group G2 with a negative refractive power, and a third lens group G3 with a positive refractive power. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction. A diaphragm ST with a predetermined aperture is provided in the first lens group G1. The first lens group GR1 is configured such that a front lens group G1a, a diaphragm ST, and a rear lens group G1b are sequentially arranged from the object side; the second lens group G2 is composed of a negative lens L21; and the third lens group G13 is composed of a positive lens L31.

[0094] The front lens group G1a is sequentially provided with a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14 from the object side, and the third negative lens L13 and the fourth positive lens L14 are mutually cemented to form a cemented lens; the rear lens group G1b is composed of a fifth positive lens L15.

[0095] An imaging glass plate GG is arranged between the positive lens L31 of the third lens group G3 and the image surface IMG. The back focal length is the distance from the image side of L31 to the image surface IMG.

[0096] The following shows various numerical data regarding the imaging lens of Embodiment 1. In this embodiment: f = 18.025, FNo = 1.854, 2ω = 63.46.

[0097] Table 1. Optical data of the imaging lens in Embodiment 1

[0098] No. R D Nd Vd 1 73.679 4 1.91694 35.25 2 -158.232 0.636 3 -114.631 2 1.53333 68.7 4 11.204 13.735 5 -22.689 1 1.80803 26.08 6 31.157 6 1.91681 35.25 7 -23.851 4 STO inf 5.370 ASPH 18.400 5.5 1.53342 56.04 ASPH -22.758 D(10) ASPH -10.000 2.2 1.62061 25.92 ASPH -36.459 D(12) 13 142.272 5.4926 1.52792 70.33 14 -17.635 15.000 15 inf 2 1.51872 64.2 21 inf 1

[0099] Table 2. Focusing data of the imaging lens in Embodiment 1

[0100] Infinity Intermediate distance Closest distance D(0) inf 705.73 104.88 D(10) 5.30 5.55 6.79 D(12) 6.76 6.52 5.28

[0101] Table 3, Aspherical Data in the Structural Parameters of the Imaging Lens in Embodiment 1

[0102]

[0103]

[0104] Figures 2A - 2C They are diagrams respectively illustrating the various aberration diagrams of the imaging lens in Embodiment 1 when focusing at infinity (β = 0.0, inf), at an intermediate distance (β = 0.025), and at the closest distance. Among them, Figures 2A - 2C from left to right in [Figure] are the schematic diagrams of spherical aberration, astigmatism, and distortion obtained based on the imaging lens in Embodiment 1. In the schematic diagram of spherical aberration, the dotted line, solid line, and dash-dotted line respectively represent the spherical aberration at the d-line (wavelength 587.56 nm), c-line (wavelength 656.28 nm), and g-line (wavelength 435.84 nm). In the schematic diagram of astigmatism, the dotted line S represents the value of the chief ray at the d-line on the sagittal image plane, and the dotted line T represents the value of the chief ray at the d-line on the meridional image plane.

[0105] Just as Figures 2A to 2C shown in [Figure], the imaging lens of Embodiment 1 has excellent imaging performance.

[0106] Embodiment 2

[0107] The following will refer to Figure 3 、 Figures 4A - 4C to describe in detail the imaging lens involved in Embodiment 2 of the present invention.

[0108] Figure 3 is a cross-sectional view along the optical axis of the structure of the imaging lens of Embodiment 2 of the present invention.

[0109] The imaging lens in this embodiment is configured such that the following lens groups are sequentially arranged from the object side shown in Figure 3 : a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, and a third lens group G3 with positive optical power. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction. A diaphragm ST with a predetermined aperture is provided in the first lens group G1. The first lens group GR1 is configured such that a front lens group G1a, a diaphragm ST, and a rear lens group G1b are sequentially arranged from the object side; the second lens group G2 is composed of a negative lens L21; and the third lens group G13 is composed of a positive lens L31.

[0110] The front lens group G1a is sequentially arranged with a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14 from the object side, wherein the third negative lens L13 and the fourth positive lens L14 are cemented to each other; the rear lens group G1b is composed of a fifth positive lens L15.

[0111] The imaging glass plate GG is arranged between the positive lens L31 of the third lens group G3 and the image surface IMG. The back intercept is the distance from the image side of L31 to the image surface IMG.

[0112] Hereinafter, various numerical data of the imaging lens according to the second embodiment are shown. In this embodiment: f = 20.60, FNo = 1.854, 2ω = 56.84.

[0113] Table 4. Optical data of the imaging lens in the second embodiment

[0114]

[0115]

[0116] Table 5. Focusing data of the imaging lens in the second embodiment

[0117] Infinity Intermediate distance Closest distance D(0) inf 0.00 807.79 D(10) 5.73 6.03 7.52 D(12) 6.95 6.65 5.16

[0118] Table 6. Aspherical data in the structural parameters of the imaging lens in the second embodiment

[0119] No. K A4 A6 A8 A10 12 1.0396E+00 -5.3684E-05 -1.7733E-08 -8.3410E-10 1.0005E-12 13 2.5510E+00 2.8461E-05 6.6088E-07 -5.3815E-09 3.0494E-11 15 -4.8274E+00 5.9871E-04 -1.0525E-05 1.0409E-07 -4.7519E-10 16 2.6894E+00 9.9078E-04 -1.2339E-05 9.9500E-08 -3.9139E-10

[0120] Figures 4A - 4C They are respectively diagrams illustrating various aberration diagrams of the imaging lens according to the second embodiment when focusing at infinity (β = 0.0, inf), at an intermediate distance (β = 0.025), and at the closest distance. Among them, Figures 4A - 4C from left to right are the schematic diagrams of spherical aberration, astigmatism, and distortion obtained based on the imaging lens according to the second embodiment. The above descriptions of various aberration curves are the same as those in other examples, and the repeated descriptions are omitted here.

[0121] Just as Figures 4A to 4C shown in, the imaging lens of the second embodiment has excellent imaging performance.

[0122] Embodiment Three

[0123] Hereinafter, reference is made to Figure 5 , Figures 6A - 6C to describe in detail the imaging lens according to the third embodiment of the present invention.

[0124] Figure 5 is a cross-sectional view along the optical axis of the structure of the imaging lens according to the third embodiment of the present invention.

[0125] The imaging lens in this embodiment is configured such that the following lens groups are sequentially arranged from the object side as shown: a first lens group G1 with a positive refractive power, a second lens group G2 with a negative refractive power, and a third lens group G3 with a positive refractive power. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction. A diaphragm ST with a predetermined aperture is provided within the first lens group G1. The first lens group GR1 is configured such that a front lens group G1a, a diaphragm ST, and a rear lens group G1b are sequentially arranged from the object side; the second lens group G2 is composed of a negative lens L21; and the third lens group G13 is composed of a positive lens L31. Figure 5 The front lens group G1a is sequentially arranged with a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14 from the object side, where the third negative lens L13 and the fourth positive lens L14 are cemented together; the rear lens group G1b is composed of a fifth positive lens L15.

[0126] An imaging glass plate GG is arranged between the positive lens L31 of the third lens group G3 and the image surface IMG. The back focal length is the distance from the image side of L31 to the image surface IMG.

[0127] Hereinafter, various numerical data regarding the imaging lens of the third embodiment are shown. In this embodiment: f = 25.75, FNo = 1.854, 2ω = 46.8.

[0128] Table 7, Optical data of the imaging lens in the third embodiment

[0129] Table 8, Focusing data of the imaging lens in the third embodiment

[0130] No. R D Nd Vd 1 34.800 5 1.90029 31.39 2 446.032 3.000 3 -120.037 2 1.52273 72 4 10.830 10.428 5 -24.235 1 1.80767 25.26 6 20.175 6 1.91694 35.25 7 -23.036 1.5 STO inf 2.500 ASPH 22.639 5.5 1.53342 56.04 ASPH -29.256 D(10) ASPH -12.158 2.2 1.62061 25.92 ASPH -66.524 D(12) 13 88.614 5 1.75337 41.34 14 -28.045 19.758 15 inf 2 1.51872 64.2 21 inf 1

[0131] Table 9, Aspherical data among the structural parameters of the imaging lens in the third embodiment

[0132] Infinity Intermediate distance Closest distance D(0) inf 1016.53 158.17 D(10) 2.80 3.20 5.23 D(12) 10.31 9.91 7.89

[0133] Table 9, Aspherical data among the structural parameters of the imaging lens in the third embodiment

[0134] No. K A4 A6 A8 A10 12 -1.1017E-01 -3.9575E-05 -2.4523E-07 1.5801E-09 -3.0189E-11 13 6.0021E+00 -2.0147E-05 9.2554E-07 -1.1074E-08 5.2170E-11 15 -6.1748E+00 4.2716E-04 -6.3071E-06 4.7463E-08 -1.5623E-10 16 -1.0000E+01 7.4871E-04 -8.8292E-06 6.4047E-08 -2.2685E-10

[0135] Figures 6A - 6C They are respectively diagrams illustrating various aberration diagrams of the imaging lens according to the third embodiment when focused at infinity (β = 0.0, inf), at an intermediate distance (β = 0.025), and at the closest distance. Among them, Figures 6A - 6C from left to right are a schematic diagram of spherical aberration, a schematic diagram of astigmatism, and a schematic diagram of distortion obtained based on the imaging lens in the third embodiment. The above description of various aberration curves is the same as that in other examples, and the repeated description is omitted here.

[0136] Just asFigures 6A to 6C As shown, the imaging lens of Embodiment 3 has excellent imaging performance.

[0137] Embodiment 4

[0138] The following refers to Figure 7 and Figures 8A - 8C to describe in detail the imaging lens involved in Embodiment 4 of the present invention.

[0139] Figure 7 is a cross-sectional view along the optical axis of the structure of the imaging lens of Embodiment 4 of the present invention.

[0140] The imaging lens in this embodiment is configured such that the following lens groups are sequentially arranged from the Figure 7 object side shown: a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, and a third lens group G3 with positive optical power. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction. A diaphragm ST with a predetermined aperture is provided in the first lens group G1. The first lens group GR1 is configured such that a front lens group G1a, a diaphragm ST, and a rear lens group G1b are sequentially arranged from the object side; the second lens group G2 is composed of a negative lens L21; and the third lens group G13 is composed of a positive lens L31.

[0141] The front lens group G1a is sequentially provided with a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14 from the object side, where the third negative lens L13 and the fourth positive lens L14 are mutually cemented; the rear lens group G1b is composed of a fifth positive lens L15.

[0142] An imaging glass plate GG is arranged between the positive lens L31 of the third lens group G3 and the image surface IMG. The back focal length is the distance from the image side of L31 to the image surface IMG.

[0143] The following shows various numerical data regarding the imaging lens of Embodiment 4. In this embodiment: f = 30.9, FNo = 1.854, 2ω = 39.5.

[0144] Table 10. Optical data of the imaging lens in Embodiment 4

[0145]

[0146]

[0147] Table 11. Focusing data of the imaging lens in Embodiment 4

[0148] Infinity Intermediate distance Closest distance D(0) inf 1227.20 197.17 D(10) 3.25 3.77 6.38 D(12) 10.74 10.22 7.61

[0149] Table 12. Aspherical data among the structural parameters of the imaging lens in Embodiment 4

[0150] No. K A4 A6 A8 A10 12 -4.9560E-01 -4.6701E-05 -3.0489E-07 9.6910E-10 -2.8989E-11 13 5.9512E+00 -3.3772E-05 4.2862E-07 -5.7612E-09 2.3281E-11 15 -6.6719E+00 3.9270E-04 -6.0717E-06 5.1604E-08 -2.0200E-10 16 1.0000E+01 6.6138E-04 -7.8352E-06 6.0618E-08 -2.3628E-10

[0151] Figures 8A - 8C These are respectively the aberration diagrams of the imaging lens according to the fourth embodiment when focusing at infinity (β = 0.0, inf), at an intermediate distance (β = 0.025), and at the closest distance. Among them, Figures 8A - 8C from left to right are respectively the schematic diagrams of spherical aberration, astigmatism, and distortion obtained based on the imaging lens in the fourth embodiment. The above descriptions of various aberration curves are the same as those in other examples, and the repeated descriptions are omitted here.

[0152] Just as Figures 8A to 8C shown in, the imaging lens of the fourth embodiment has excellent imaging performance.

[0153] Embodiment Five

[0154] The following refers to Figure 9 and Figures 10A - 10C to describe in detail the imaging lens related to the fifth embodiment of the present invention.

[0155] Figure 9 is a cross-sectional view along the optical axis of the structure of the imaging lens of the fifth embodiment of the present invention.

[0156] The imaging lens in this embodiment is configured such that the following lens groups are sequentially arranged from the Figure 9 shown object side: a first lens group G1 with a positive optical power, a second lens group G2 with a negative optical power, and a third lens group G3 with a positive optical power. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction. A diaphragm ST with a predetermined aperture is provided in the first lens group G1. The first lens group GR1 is configured such that a front lens group G1a, a diaphragm ST, and a rear lens group G1b are sequentially arranged from the object side; the second lens group G2 is composed of a negative lens L21; and the third lens group G13 is composed of a positive lens L31.

[0157] The front lens group G1a is sequentially provided with a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14 from the object side, where the third negative lens L13 and the fourth positive lens L14 are mutually cemented; the rear lens group G1b is composed of a fifth positive lens L15.

[0158] An imaging glass plate GG is arranged between the positive lens L31 of the third lens group G3 and the image surface IMG. The back focal length is the distance from the image side of L31 to the image surface IMG.

[0159] The following shows various numerical data of the imaging lens according to Embodiment 5. In this embodiment: f = 34.1, FNo = 1.925, 2ω = 35.8.

[0160] Table 13. Optical Data of the Imaging Lens in Embodiment 5

[0161] No. R D Nd Vd 1 25.933 5 1.91342 34.37 2 365.399 3.000 3 -98.408 2 1.51872 64.2 4 10.553 5.716 5 -23.136 1 1.81927 24.87 6 15.141 6 1.90763 35.5 7 -25.157 1.5 STO inf 5.714 ASPH 29.962 5.5 1.53342 56.04 ASPH -28.812 D(10) ASPH -14.291 2.2 1.62061 25.92 ASPH -92.180 D(12) 13 63.601 5 1.81659 38.46 14 -37.228 20.137 15 inf 2 1.51872 64.2 21 inf 1

[0162] Table 14. Focusing Data of the Imaging Lens in Embodiment 5

[0163] Infinity Intermediate distance Closest distance D(0) inf 1356.58 219.74 D(10) 3.46 4.11 7.41 D(12) 10.77 10.12 6.82

[0164] Table 15. Aspherical Data among the Structural Parameters of the Imaging Lens in Embodiment 5

[0165] No. K A4 A6 A8 A10 12 2.1067E-01 -4.1644E-05 -2.1509E-07 1.5922E-10 -1.4131E-11 13 5.1054E+00 -2.1062E-05 3.1140E-07 -3.9437E-09 1.8817E-11 15 -5.9966E+00 3.6536E-04 -5.3557E-06 4.4939E-08 -1.7631E-10 16 1.0000E+01 5.5579E-04 -6.0581E-06 4.3760E-08 -1.5919E-10

[0166] Figures 10A - 10C They are respectively diagrams illustrating various aberration diagrams of the imaging lens according to Embodiment 5 when focusing at infinity (β = 0.0, inf), at intermediate distance (β = 0.025), and at the closest distance. Among them, Figures 10A - 10C from left to right are a schematic diagram of spherical aberration, a schematic diagram of astigmatism, and a schematic diagram of distortion obtained based on the imaging lens according to Embodiment 5. The above descriptions of various aberration curves are the same as those in other examples, and the repeated descriptions are omitted here.

[0167] Just as Figures 10A to 10C shown, the imaging lens of Embodiment 5 has excellent imaging performance.

[0168] Embodiment 6

[0169] The following refers to Figure 11 、 Figures 12A - 12C to describe in detail the imaging lens involved in Embodiment 6 of the present invention.

[0170] Figure 11 is a sectional view along the optical axis of the structure of the imaging lens according to Embodiment 6 of the present invention.

[0171] The imaging lens in this embodiment is configured such that the following lens groups are sequentially arranged from the object side shown in Figure 11 : a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, and a third lens group G3 with positive refractive power. During the focusing process of the imaging lens, the second lens group G2 can move along the optical axis direction. A diaphragm ST with a predetermined aperture is disposed within the first lens group G1. The first lens group GR1 is configured such that a front lens group G1a, the diaphragm ST, and a rear lens group G1b are sequentially arranged from the object side; the second lens group G2 is composed of a negative lens L21; and the third lens group G13 is composed of a positive lens L31.

[0172] The front lens group G1a is sequentially provided with a first positive lens L11, a second negative lens L12, a third negative lens L13, and a fourth positive lens L14 from the object side, wherein the third negative lens L13 and the fourth positive lens L14 are cemented to each other; the rear lens group G1b is composed of a fifth positive lens L15.

[0173] The imaging glass plate GG is disposed between the positive lens L31 of the third lens group G3 and the image surface IMG. The back intercept is the distance from the image side of L31 to the image surface IMG.

[0174] Hereinafter, various numerical data of the imaging lens according to Example 6 are shown. In this embodiment: f = 38.8, FNo = 1.90, 2ω = 31.0.

[0175] Table 1. Optical data of the imaging lens in Example 6

[0176] No. R D Nd Vd 1 23.614 5 1.91367 35.34 2 271.260 2.929 3 -129.464 2 1.52362 63.84 4 10.844 6.250 5 -25.499 1 1.84655 24.03 6 15.075 7 1.89646 35.81 7 -28.035 1.5 STO inf 4.747 ASPH 26.457 5.5 1.53342 56.04 ASPH -31.261 D(10) ASPH -11.438 2.2 1.62061 25.92 ASPH -47.751 D(12) 13 67.421 5 1.79323 31.23 14 -33.590 17.304 15 inf 2 1.51872 64.2 21 inf 1

[0177] Table 2. Focus adjustment data of the imaging lens in Example 6

[0178] Infinity Intermediate distance Closest distance D(0) inf 1541.28 247.75 D(10) 5.70 6.31 9.45 D(12) 10.87 10.26 7.12

[0179] Table 3. Aspherical data in the structural parameters of the imaging lens in Example 6

[0180] No. K A4 A6 A8 A10 12 9.3418E-01 -3.7862E-05 -2.1869E-08 -1.4650E-09 7.6640E-13 13 5.7736E+00 -1.1710E-05 4.1878E-07 -4.8038E-09 2.4151E-11 15 -5.2208E+00 4.5747E-04 -7.1551E-06 6.2454E-08 -2.4604E-10 16 -2.0097E+00 7.3672E-04 -8.5926E-06 6.4837E-08 -2.3411E-10

[0181] Figures 12A - 12C They are respectively diagrams illustrating various aberration diagrams of the imaging lens according to Example 6 at infinity focus (β = 0.0, inf), intermediate distance focus (β = 0.025), and closest distance focus. Among them, Figures 12A - 12C from left to right are a schematic diagram of spherical aberration, a schematic diagram of astigmatism, and a schematic diagram of distortion obtained based on the imaging lens according to Example 6. The above description of various aberration curves is the same as that in other examples, and the repeated description thereof is omitted here.

[0182] Just as Figures 12A to 12C shown in, the imaging lens of Example 6 has excellent imaging performance.

[0183] For the imaging lens of the present invention, by providing an aspherical lens with a positive optical power in the rear lens group and an aspherical lens with a negative optical power in the second lens group to reduce spherical aberration and astigmatism, good optical performance is achieved; by defining that the focal length of the front lens group satisfies 2.5 ≤ |f1a / f23| ≤ 20 with the combined focal length of the second lens group and the third lens group, the imaging lens satisfies large aperture, low chromatic aberration, miniaturization, and low cost, and also has high-quality imaging performance.

[0184] It should be noted that the specific parameters in the above table are only illustrative. The parameters of each lens are not limited to the values shown in the above numerical examples, and other values can be adopted, and similar or the same technical effects can be achieved.

[0185] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It is not intended to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An imaging lens, characterized in that: It includes a first lens group with positive optical power, a second lens group with negative optical power, and a third lens group with positive optical power, which are sequentially arranged along the optical axis from the object side to the image side; During the focusing process of the imaging lens, the second lens group moves along the optical axis direction; the first lens group sequentially includes a front lens group, a diaphragm, and a rear lens group; The imaging lens satisfies the following conditional formula: 2.5 ≤ |f1a / f23| ≤ 20 (1) where f1a is the focal length of the front lens group; f23 is the combined focal length of the second lens group and the third lens group; The front lens group sequentially includes a first positive lens, a second negative lens, a third negative lens, and a fourth positive lens, and the rear lens group includes an aspherical lens with positive optical power; the second lens group includes an aspherical lens with negative optical power; The first lens group satisfies the following conditional formula: 1.1 < f / f1 < 1.5 (2) where f1 is the focal length of the first lens group; f is the focal length of the imaging lens.

2. The imaging lens according to claim 1, wherein The second lens group satisfies the following conditional formula: -1.8 < f / f2 < -0.6 (3) where f2 is the focal length of the second lens group; f is the focal length of the imaging lens.

3. The imaging lens according to claim 2, characterized in that, The third lens group satisfies the following conditional formula: 0.5 < f / f3 < 1.4 (4) where f3 is the focal length of the third lens group; f is the focal length of the imaging lens.

4. The imaging lens according to any one of claims 1-3, characterized in that, The imaging lens satisfies the following conditional formula: 1 <(TL-BF) / f < 3.5 (5) where TL is the overall length of the imaging lens; BF is the distance between the lens surface closest to the image side in the imaging lens and the image plane; f is the focal length of the imaging lens.

5. The imaging lens according to claim 1, wherein The aspherical lens satisfies the following conditional formula: z = CY 2 / [1 + {1 - (1 + k)c 2 Y 2} 1 / 2 + A4Y 4 + A6Y 6 + A8Y 8 + A10Y 10 where z is the aspherical depth; C is the paraxial curvature; Y is the height from the optical axis to the lens; k is the eccentricity; A4 is the 4th-order aspherical coefficient; A6 is the 6th-order aspherical coefficient; A8 is the 8th-order aspherical coefficient; A10 is the 10th-order aspherical coefficient.

6. A camera device including the imaging lens according to any one of claims 1 to 5.

7. The imaging device according to claim 6, characterized in that, The camera device further includes an imaging element, and the imaging element is used to output a camera signal corresponding to the optical image formed by the imaging lens.

Images