Imaging lens and camera device

Abstract

The present application provides an imaging lens capable of shortening the total length of the lens system and having good optical performance, and a camera device provided with the imaging lens. The imaging lens comprises, in order from the object side, a first lens group, an aperture, a positive second lens group and a third lens group. During focusing, at least the second lens group moves, and the third lens group does not move. The second lens group comprises at least two negative lenses. The third lens group comprises one negative lens and one positive lens.

Description

Technical Field

[0001] This invention relates to an imaging lens and a camera device. Background Technology

[0002] Previously, the lens system described in Patent Document 1 below was known as an imaging lens for digital cameras and the like.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-029658

[0004] In recent years, there has been a demand for imaging lenses with a short overall length and good optical performance. Summary of the Invention

[0005] The present invention was made in view of the above circumstances, and its object is to provide an imaging lens that can shorten the total length of the lens system and has good optical performance, and a camera device having the imaging lens.

[0006] The imaging lens of the present invention includes, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group. During focusing, at least the second lens group moves along the optical axis, and the third lens group is fixed relative to the image plane. The second lens group includes at least two negative lenses, and the third lens group includes one negative lens and one positive lens.

[0007] When the focal length of the first lens group is set to f1 and the focal length of the second lens group is set to f2, the imaging lens of the present invention preferably satisfies the following condition (1), and more preferably satisfies the following condition (1-1).

[0008] -0.5<f2 / f1<1 (1)

[0009] -0.3 < f2 / f1 < 0.9 (1-1)

[0010] Preferably, the second lens group includes at least two positive lenses, and a meniscus lens with its concave surface facing the object side is disposed on the image-side of the second lens group.

[0011] When the paraxial radius of curvature of the object-side surface of the lens closest to the image side of the second lens group is set to R2rA and the paraxial radius of curvature of the image-side surface of the lens closest to the image side of the second lens group is set to R2rB, the imaging lens of the present invention preferably satisfies the following condition (2), and more preferably satisfies the following condition (2-1).

[0012] -0.3<(R2rB-R2rA) / (R2rB+R2rA)<0.3 (2)

[0013] -0.15<(R2rB-R2rA) / (R2rB+R2rA)<0.15 (2-1)

[0014] When the focal length of the second lens group is set to f2 and the focal length of the lens closest to the image side of the second lens group is set to f2R, the imaging lens of the present invention preferably satisfies the following condition (3), and more preferably satisfies the following condition (3-1).

[0015] -0.4 < f2 / f2R < 0.6 (3)

[0016] -0.3 < f2 / f2R < 0.5 (3-1)

[0017] Preferably, the second lens group includes, from the object side to the image side, two sets of conjoined lenses and a meniscus lens with its concave surface facing the object side.

[0018] Preferably, the first lens group includes at least one negative lens and at least one positive lens.

[0019] Preferably, the first lens group includes two negative lenses and one positive lens sequentially from the object side to the image side.

[0020] Preferably, the absolute value of the radius of curvature of the object-side surface of the negative lens of the third lens group is smaller than the absolute value of the radius of curvature of the image-side surface.

[0021] Preferably, the third lens group is provided with a negative lens and a positive lens in sequence from the object side to the image side.

[0022] When the focal length of the imaging lens is set to f when it is focused on an object at infinity, and the focal length of the first lens group is set to f1, the imaging lens of the present invention preferably satisfies the following condition (4).

[0023] -0.6 < f / f1 < 1.5 (4)

[0024] When the focal length of the imaging lens is set to f when focusing on an object at infinity, and the focal length of the second lens group is set to f2, the imaging lens of the present invention preferably satisfies the following condition (5).

[0025] 0.6 < f / f² < 1.8 (5)

[0026] When the focal length of the imaging lens is set to f when focusing on an object at infinity, and the focal length of the third lens group is set to f3, the imaging lens of the present invention preferably satisfies the following condition (6).

[0027] -0.8 < f / f3 < 0.4 (6)

[0028] When the focal length of the positive lens of the third lens group is set to f3p and the focal length of the imaging lens in the state of focusing on an object at infinity is set to f, the imaging lens of the present invention preferably satisfies the following condition (7).

[0029] 0.5 < f3p / f < 3 (7)

[0030] Preferably, when the maximum half angle of view of the imaging lens in the state of focusing on an object at infinity is set to ωmax, the distance on the optical axis from the lens surface of the third lens group closest to the object to the lens surface of the third lens group closest to the image is set to T3, and the focal length of the imaging lens in the state of focusing on an object at infinity is set to f, ωmax is 30 degrees or more, and the imaging lens of the present invention satisfies the following conditional expression (8).

[0031] 0.2<T3 / {f×tan(ωmax)}<0.6 (8)

[0032] When the paraxial radius of curvature of the object-side surface of the negative lens of the third lens group is set to R3nA and the paraxial radius of curvature of the image-side surface of the negative lens of the third lens group is set to R3nB, the imaging lens of the present invention preferably satisfies the following condition (9).

[0033] 0.2<(R3nB-R3nA) / (R3nB+R3nA)<2 (9)

[0034] The camera device of the present invention includes the imaging lens of the present invention.

[0035] In addition, the terms "including" and "including" in this specification mean that, in addition to the constituent elements listed, it may also include lenses that do not substantially have refractive power, as well as optical elements other than lenses such as apertures, filters and cover glass, and mechanism parts such as lens flanges, lens barrels, imaging elements and hand shaking correction mechanisms.

[0036] In addition, in this specification, "a group with positive refractive power" means that the group as a whole has positive refractive power. Similarly, "a group with negative refractive power" means that the group as a whole has negative refractive power. "Lens with positive refractive power," "positive lens," and "positive lens" have the same meaning. "Lens with negative refractive power," "negative lens," and "negative lens" have the same meaning. "A group of lenses" is not limited to a structure that includes multiple lenses; it can also be a structure that includes only one lens. "Single lens" means a single lens that is not joined together.

[0037] A compound aspherical lens (a lens in which a spherical lens and an aspherical film formed on the spherical lens are integrated to function as a single aspherical lens) is used as a single lens and not considered as a combined lens. Unless otherwise specified, the sign of the refractive power, surface shape, and radius of curvature associated with lenses including aspherical surfaces are assumed to be considered in the paraxial region. Regarding the sign of the radius of curvature, the radius of curvature of a surface with a convex shape facing the object side is given a positive sign, and the radius of curvature of a surface with a convex shape facing the image side is given a negative sign.

[0038] The "focal length" used in the conditional expressions refers to the paraxial focal length. Except for some dispersion ratios, the values ​​used in the conditional expressions are based on the d-line. The "d-line," "C-line," "F-line," and "g-line" described in this specification are bright lines. In this specification, the wavelength of the d-line is considered to be 587.56 nm, the wavelength of the C-line is considered to be 656.27 nm, the wavelength of the F-line is considered to be 486.13 nm, and the wavelength of the g-line is considered to be 435.84 nm.

[0039] Invention Effects

[0040] According to the present invention, it is possible to provide an imaging lens that shortens the overall length of the lens system and has good optical performance, and a camera device having the imaging lens. Attached Figure Description

[0041] Figure 1 The image lens corresponding to Embodiment 1 is a cross-sectional view showing the structure and beam of the image lens according to one embodiment.

[0042] Figure 2 This is a diagram of the aberrations of the imaging lens in Example 1.

[0043] Figure 3 This is a cross-sectional view showing the structure of the imaging lens and the light beam of Embodiment 2.

[0044] Figure 4 This is a diagram of the aberrations of the imaging lens in Example 2.

[0045] Figure 5 This is a cross-sectional view showing the structure of the imaging lens and the light beam of Embodiment 3.

[0046] Figure 6 These are aberration diagrams of the imaging lens in Example 3.

[0047] Figure 7 This is a cross-sectional view showing the structure of the imaging lens and the beam of Embodiment 4.

[0048] Figure 8 This is a diagram of the aberrations of the imaging lens in Example 4.

[0049] Figure 9 This is a cross-sectional view showing the structure of the imaging lens and the beam of Embodiment 5.

[0050] Figure 10 This is a diagram of the aberrations of the imaging lens in Example 5.

[0051] Figure 11 This is a cross-sectional view showing the structure of the imaging lens and the beam of Embodiment 6.

[0052] Figure 12This is a diagram of the aberrations of the imaging lens in Example 6.

[0053] Figure 13 This is a cross-sectional view showing the structure of the imaging lens and the light beam of Embodiment 7.

[0054] Figure 14 This is a diagram of the aberrations of the imaging lens in Example 7.

[0055] Figure 15 This is a perspective view of the front side of a camera device according to an embodiment of the present invention.

[0056] Figure 16 This is a perspective view of the rear side of a camera device according to an embodiment of the present invention. Detailed Implementation

[0057] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 The diagram illustrates the structure of an imaging lens, including a cross-section of the optical axis Z, and the beam according to an embodiment of the present invention. Figure 1 The example shown corresponds to the imaging lens of Embodiment 1, which will be described later. Figure 1 In the image, the left side is the object side, and the right side is the image side, illustrating the state of focusing on an object at infinity. As a light beam, Figure 1 The image also shows the on-axis beam 2 and the beam 3 with the maximum viewing angle. In the following description, the "imaging lens of the present invention" will also be referred to simply as the "imaging lens".

[0058] In addition, Figure 1 The image illustrates an example where, assuming the imaging lens is suitable for a camera device, a parallel flat optical component PP is positioned between the imaging lens and the image plane (Sim). The optical component PP is assumed to be a component such as various filters and / or cover glass. These filters include, for example, low-pass filters, infrared cutoff filters, and filters that cut off specific wavelength regions. The optical component PP may be a component without refractive power, or it may be a structure in which the optical component PP is omitted.

[0059] The imaging lens, along the optical axis Z from the object side to the image side, consists of a first lens group G1, an aperture St, a second lens group G2, and a third lens group G3. As an example, in... Figure 1 In the imaging lens shown, the first lens group G1 includes three lenses L11 to L13 from the object side to the image side, the second lens group G2 includes five lenses L21 to L25 from the object side to the image side, and the third lens group G3 includes two lenses L31 to L32 from the object side to the image side.

[0060] The imaging lens is configured such that, when focusing from an object at infinity to the nearest object, at least the second lens group G2 moves along the optical axis Z, while the third lens group G3 remains fixed relative to the image plane Sim. Figure 1 The image shows an example where the second lens group G2 moves toward the object side when focusing from an object at infinity to the nearest object. Figure 1 The arrow pointing to the left on the lower side of the second lens group G2 shown indicates that when focusing from an object at infinity to the nearest object, the second lens group G2 is a focusing group that moves towards the object. Hereinafter, the lens group that moves during focusing will be referred to as the "focusing group".

[0061] By fixing the third lens group G3 during focusing, the distortion of the image plane during focusing can be suppressed. Furthermore, compared to a structure where the entire imaging lens moves during focusing, the structure where the third lens group G3 is fixed during focusing allows for the miniaturization and weight reduction of the focusing group and its associated mechanical parts, thus reducing the load on the drive system and accelerating the focusing speed.

[0062] exist Figure 1 As an example, this example illustrates an internal focusing lens system where, when focusing from an object at infinity to the nearest object, the first lens group G1, in addition to the third lens group G3, is also fixed relative to the image plane Sim, while only the second lens group G2 moves. By configuring the first lens group G1 to remain fixed during focusing, further miniaturization and weight reduction of the focusing group can be achieved. Furthermore, the internal focusing structure also provides dust and water resistance.

[0063] The first lens group G1 includes a plurality of lenses with refractive power. Specifically, preferably, the first lens group G1 includes at least one negative lens and at least one positive lens. By including both negative and positive lenses in the first lens group G1, it is beneficial to effectively correct chromatic aberration at magnification.

[0064] More specifically, preferably, the first lens group G1 comprises two negative lenses and one positive lens sequentially from the object side to the image side. In this case, it is easy to achieve wide-angle coverage while suppressing distortion aberrations.

[0065] As an example, Figure 1 The first lens group G1 shown includes, from the object side to the image side, a negative lens L11, a negative lens L12, and a positive lens L13. Lens L11 is a single lens. Lenses L12 and L13 are joined together.

[0066] The second lens group G2 is configured as a lens group with positive refractive power. By setting the refractive power of the second lens group G2, which is close to the aperture St, it is easy to give the entire lens system sufficient refractive power while suppressing the effects on distortion aberrations and astigmatism.

[0067] Furthermore, the second lens group G2 is configured to include at least two negative lenses. By having two or more lenses share the negative refractive power, spherical aberration can be easily and effectively corrected.

[0068] Furthermore, preferably, the second lens group G2 includes at least two positive lenses. By having two or more lenses share the positive refractive power required by the second lens group G2, the generation of spherical aberration can be suppressed.

[0069] Preferably, a meniscus lens with its concave surface facing the object side is disposed on the image-side of the second lens group G2. By setting the image-side lens of the second lens group G2 as a meniscus lens with its concave surface facing the object side, it is beneficial to maintain the balance of astigmatism.

[0070] When a meniscus lens with its concave surface facing the object side is disposed on the image side of the second lens group G2, it is preferable that at least one of the object-side surface and the image-side surface of the meniscus lens is aspherical. In this case, it is beneficial to correct spherical aberration, suppress variations in spherical aberration during focusing, and suppress variations in image plane curvature during focusing.

[0071] Preferably, the second lens group G2 comprises, from the object side to the image side, two sets of conjoined lenses and a meniscus lens with its concave surface facing the object side. In this case, a simple structure can be adopted, and it is easy to maintain the balance between on-axis chromatic aberration, magnification chromatic aberration, spherical aberration, and image plane curvature.

[0072] As an example, Figure 1 The second lens group G2 shown includes, from the object side to the image side, a positive lens L21, a negative lens L22, a negative lens L23, a positive lens L24, and a negative lens L25. Lenses L21 and L22 are joined together. Lenses L23 and L24 are joined together. Lens L25 is an aspherical lens and is a meniscus lens with its concave surface facing the object side in the paraxial region.

[0073] The third lens group G3 is configured to include one negative lens and one positive lens. This structure facilitates effective correction of chromatic aberration and distortion aberrations. Furthermore, by using only two lenses to constitute the third lens group G3, the overall length of the lens system can be shortened, thus contributing to a thinner optical system.

[0074] Preferably, the third lens group G3 has a negative lens and a positive lens arranged sequentially from the object side to the image side. By arranging the negative lens and positive lens sequentially from the object side, it is easy to reduce the angle of incidence of the principal ray relative to the image plane Sim.

[0075] Preferably, the absolute value of the radius of curvature of the object-side surface of the negative lens of the third lens group G3 is smaller than the absolute value of the radius of curvature of the image-side surface. In this case, astigmatism can be suppressed.

[0076] Next, the conditional expressions that the imaging lens preferably satisfies will be described. However, the conditional expressions that the imaging lens preferably satisfies are not limited to those expressed in formula form, but also include all conditional expressions obtained by arbitrarily combining the lower and upper limits from the preferred, more preferred and further preferred conditional expressions.

[0077] When the focal length of the first lens group G1 is set to f1 and the focal length of the second lens group G2 is set to f2, the imaging lens preferably satisfies the following condition (1). By ensuring that the corresponding value of condition (1) is not below the lower limit, it is beneficial to shorten the total length of the lens system. By ensuring that the corresponding value of condition (1) is not above the upper limit, it is beneficial to ensure the back focal length. In order to obtain better characteristics, the imaging lens more preferably satisfies the following condition (1-1), and even more preferably satisfies the following condition (1-2).

[0078] -0.5<f2 / f1<1 (1)

[0079] -0.3 < f2 / f1 < 0.9 (1-1)

[0080] -0.2 < f2 / f1 < 0.8 (1-2)

[0081] When the paraxial radius of curvature of the object-side surface of the lens closest to the image side of the second lens group G2 is set to R2rA, and the paraxial radius of curvature of the image-side surface of the lens closest to the image side of the second lens group G2 is set to R2rB, the imaging lens preferably satisfies the following condition (2). By ensuring that the corresponding value of condition (2) is not below the lower limit, the generation of astigmatism can be suppressed. By ensuring that the corresponding value of condition (2) is not above the upper limit, it is beneficial to correct spherical aberration. In order to obtain better characteristics, the imaging lens more preferably satisfies the following condition (2-1), and even more preferably satisfies the following condition (2-2).

[0082] -0.3<(R2rB-R2rA) / (R2rB+R2rA)<0.3 (2)

[0083] -0.15<(R2rB-R2rA) / (R2rB+R2rA)<0.15 (2-1)

[0084] -0.1<(R2rB-R2rA) / (R2rB+R2rA)<0.1 (2-2)

[0085] When the focal length of the second lens group G2 is set to f2 and the focal length of the lens closest to the image side of the second lens group G2 is set to f2R, the imaging lens preferably satisfies the following condition (3). By making the corresponding value of condition (3) within the range of condition (3), the generation of magnification chromatic aberration can be suppressed. In order to obtain better characteristics, the imaging lens more preferably satisfies the following condition (3-1), and even more preferably satisfies the following condition (3-2).

[0086] -0.4 < f2 / f2R < 0.6 (3)

[0087] -0.3 < f2 / f2R < 0.5 (3-1)

[0088] -0.2 < f2 / f2R < 0.4 (3-2)

[0089] When the focal length of the imaging lens is set to f when focusing on an object at infinity, and the focal length of the first lens group G1 is set to f1, the imaging lens preferably satisfies the following condition (4). By ensuring that the corresponding value of condition (4) is not below the lower limit, it is beneficial to shorten the total length of the lens system. By ensuring that the corresponding value of condition (4) is not above the upper limit, it is beneficial to achieve a wide angle. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (4-1), and even more preferably satisfies the following condition (4-2).

[0090] -0.6 < f / f1 < 1.5 (4)

[0091] -0.4 < f / f1 < 1.1 (4-1)

[0092] -0.2 < f / f1 < 0.88 (4-2)

[0093] When the focal length of the imaging lens is set to f when focusing on an object at infinity, and the focal length of the second lens group G2 is f2, the imaging lens preferably satisfies the following condition (5). By ensuring that the corresponding value of condition (5) is not below the lower limit, the amount of movement of the second lens group G2 during focusing can be shortened, thereby facilitating a reduction in the overall length of the lens system. By ensuring that the corresponding value of condition (5) is not above the upper limit, variations in spherical aberration and image plane curvature during focusing can be suppressed. To obtain even better characteristics, the imaging lens more preferably satisfies the following condition (5-1), and even more preferably satisfies the following condition (5-2).

[0094] 0.6 < f / f² < 1.8 (5)

[0095] 0.8 < f / f² < 1.6 (5-1)

[0096] 0.9 < f / f² < 1.4 (5-2)

[0097] When the focal length of the imaging lens is set to f when focusing on an object at infinity, and the focal length of the third lens group G3 is f3, the imaging lens preferably satisfies the following condition (6). By ensuring that the corresponding value of condition (6) is not below the lower limit, it is easy to reduce the angle of incidence of the principal ray relative to the image plane Sim. By ensuring that the corresponding value of condition (6) is not above the upper limit, a stronger positive refractive power can be configured on the object side within the imaging lens, which is beneficial for shortening the overall length of the lens system. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (6-1), and even more preferably satisfies the following condition (6-2).

[0098] -0.8 < f / f3 < 0.4 (6)

[0099] -0.6 < f / f3 < 0.2 (6-1)

[0100] -0.5 < f / f3 < 0.1 (6-2)

[0101] When the focal length of the positive lens of the third lens group G3 is set to f3p, and the focal length of the imaging lens when focusing on an object at infinity is set to f, the imaging lens preferably satisfies the following condition (7). By ensuring that the corresponding value of condition (7) is not below the lower limit, the generation of distortion aberrations can be suppressed. By ensuring that the corresponding value of condition (7) is not above the upper limit, the angle of incidence of the principal ray relative to the image plane Sim can be easily reduced. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (7-1), and even more preferably satisfies the following condition (7-2).

[0102] 0.5 < f3p / f < 3 (7)

[0103] 0.6 < f3p / f < 2 (7-1)

[0104] 0.8 < f3p / f < 1.8 (7-2)

[0105] Preferably, when the maximum half-angle of the imaging lens is set to ωmax, the distance on the optical axis from the lens surface of the third lens group G3 closest to the object to the lens surface of the third lens group G3 closest to the image is set to T3, and the focal length of the imaging lens is set to f, ωmax is 30 degrees or more, and the imaging lens satisfies the following condition (8). By making ωmax 30 degrees or more, it is easy to achieve a wide angle. To further achieve a wide angle, ωmax is more preferably 34 degrees or more, and more preferably 35 degrees or more. By ensuring that the corresponding value of condition (8) is not below the lower limit, it is easy to maintain a balance of astigmatism, distortion aberration, and chromatic aberration at both low and high angles. By ensuring that the corresponding value of condition (8) is not above the upper limit, the distance between the second lens group G2 and the image plane Sim that moves during focusing can be shortened relative to the maximum image height, thus increasing the amount of movement of the focusing group during focusing while shortening the total length of the lens system. Therefore, variations in spherical aberration and image plane curvature during focusing can be suppressed. To obtain even better characteristics, the imaging lens more preferably satisfies the following condition (8-1), and even more preferably satisfies the following condition (8-2).

[0106] 0.2<T3 / {f×tan(ωmax)}<0.6 (8)

[0107] 0.24<T3 / {f×tan(ωmax)}<0.5 (8-1)

[0108] 0.26<T3 / {f×tan(ωmax)}<0.45 (8-2)

[0109] When the paraxial radius of curvature of the object-side surface of the negative lens of the third lens group G3 is set to R3nA, and the paraxial radius of curvature of the image-side surface of the negative lens of the third lens group G3 is set to R3nB, the imaging lens preferably satisfies the following condition (9). By ensuring that the corresponding value of condition (9) is not below the lower limit, the generation of spherical aberration can be suppressed. By ensuring that the corresponding value of condition (9) is not above the upper limit, the generation of distortion aberration can be suppressed. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (9-1), and even more preferably satisfies the following condition (9-2).

[0110] 0.2<(R3nB-R3nA) / (R3nB+R3nA)<2 (9)

[0111] 0.4<(R3nB-R3nA) / (R3nB+R3nA)<1.6 (9-1)

[0112] 0.5<(R3nB-R3nA) / (R3nB+R3nA)<1.4 (9-2)

[0113] When the distance on the optical axis from the object-side lens surface of the third lens group G3 to the image-side lens surface of the third lens group G3 is set to T3, and the back focal length of the imaging lens of the air-converted telescope is set to Bf, the imaging lens preferably satisfies the following condition (10). "Back focal length of the air-converted telescope" is the air-converted distance on the optical axis from the image-side lens surface to the image-side focal position of the imaging lens. By ensuring that the corresponding value of condition (10) is not below the lower limit, it is easy to maintain a balance of astigmatism, distortion aberration, and magnification chromatic aberration at both low and high angles. By ensuring that the corresponding value of condition (10) is not above the upper limit, the distance between the second lens group G2 and the image plane Sim, which moves during focusing, can be shortened relative to the back focal length. Therefore, it is possible to increase the amount of movement of the focusing group during focusing while shortening the total length of the lens system. As a result, it is possible to suppress the variation of spherical aberration and the variation of image plane curvature during focusing. To obtain better characteristics, the imaging lens is more preferably satisfied with the following condition (10-1), and even more preferably satisfied with the following condition (10-2).

[0114] 0.15 < T3 / Bf < 0.8 (10)

[0115] 0.2 < T3 / Bf < 0.7 (10-1)

[0116] 0.4 < T3 / Bf < 0.65 (10-2)

[0117] When the paraxial radius of curvature of the surface of the second lens from the image side of the second lens group G2 is set to R2sB, and the distance on the optical axis from the aperture St to the surface of the second lens from the image side of the second lens group G2 is set to S2sB, the imaging lens preferably satisfies the following condition (11). By making the corresponding value of condition (11) within the range of condition (11), astigmatism can be suppressed. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (11-1), and even more preferably satisfies the following condition (11-2).

[0118] 0.7 < -R2sB / S2sB < 1.7 (11)

[0119] 0.8 < -R²sB / S²sB < 1.5 (11-1)

[0120] 0.85<-R2sB / S2sB<1.4 (11-2)

[0121] Preferably, the first lens group G1 includes at least one negative lens and at least one positive lens. When the average value of the dispersion coefficients of all negative lenses in the first lens group G1 along the d-line reference is set to v1n, and the average value of the dispersion coefficients of all positive lenses in the first lens group G1 along the d-line reference is set to v1p, the imaging lens satisfies the following conditional expression (12). By ensuring that the corresponding value of conditional expression (12) is not below the lower limit, it is beneficial to correct magnification chromatic aberration. By ensuring that the corresponding value of conditional expression (12) is not above the upper limit, it is beneficial to correct on-axis chromatic aberration. To obtain even better characteristics, the imaging lens more preferably satisfies the following conditional expression (12-1), and even more preferably satisfies the following conditional expression (12-2).

[0122] -10<v1n-v1p<40 (12)

[0123] -4<v1n-v1p<30 (12-1)

[0124] 0 < v1n - v1p < 19 (12-2)

[0125] Preferably, the first lens group G1 includes at least one negative lens and at least one positive lens. When the average value of the partial dispersion ratio between the g-line and F-line of all the negative lenses in the first lens group G1 is set to θ1n, and the average value of the partial dispersion ratio between the g-line and F-line of all the positive lenses in the first lens group G1 is set to θ1p, the imaging lens satisfies the following conditional expression (13). By ensuring that the corresponding value of conditional expression (13) is within the range of conditional expression (13), the generation of secondary chromatic aberration can be suppressed. Furthermore, when the refractive indices of one lens relative to the g-line, F-line, and C-line are set to Ng, NF, and NC, respectively, the partial dispersion ratio θ between the g-line and F-line of that lens is defined by θ = (Ng - NF) / (NF - NC). To obtain even better characteristics, the imaging lens more preferably satisfies the following conditional expression (13-1), and even more preferably satisfies the following conditional expression (13-2).

[0126] -0.1<θ1n-θ1p<0.1 (13)

[0127] -0.06<θ1n-θ1p<0.06 (13-1)

[0128] -0.04<θ1n-θ1p<0.05 (13-2)

[0129] When the refractive index of the positive lens of the third lens group G3 relative to the d-line is set to N3p, the imaging lens preferably satisfies the following condition (14). When correcting astigmatism and distortion aberrations at low viewing angles, astigmatism and distortion aberrations at high viewing angles are easily generated, but by ensuring that the corresponding value of condition (14) is not below the lower limit, the generation of astigmatism and distortion aberrations at high viewing angles can be suppressed. By ensuring that the corresponding value of condition (14) is not above the upper limit, it is beneficial to correct astigmatism and distortion aberrations at low viewing angles. In order to obtain better characteristics, the imaging lens more preferably satisfies the following condition (14-1), and even more preferably satisfies the following condition (14-2).

[0130] 1.6 < N3p < 2.5 (14)

[0131] 1.8 < N3p < 2.2 (14-1)

[0132] 1.85 < N3p < 2.1 (14-2)

[0133] When the refractive index of the negative lens of the third lens group G3 relative to the d-line is set to N3n, the imaging lens preferably satisfies the following condition (15). By ensuring that the corresponding value of condition (15) is not below the lower limit, the generation of astigmatism and distortion aberrations at high viewing angles, which are easily generated when correcting astigmatism and distortion aberrations at low viewing angles, can be suppressed. By ensuring that the corresponding value of condition (15) is not above the upper limit, it is beneficial to correct astigmatism and distortion aberrations at low viewing angles. In order to obtain better characteristics, the imaging lens more preferably satisfies the following condition (15-1), and even more preferably satisfies the following condition (15-2).

[0134] 1.55 < N3n < 2.5 (15)

[0135] 1.6 < N3n < 2.2 (15-1)

[0136] 1.65 < N3n < 1.95 (15-2)

[0137] Preferably, the first lens group G1 includes at least one positive lens. When the average refractive index of all the positive lenses in the first lens group G1 relative to the d-line is set to N1p, the imaging lens satisfies the following condition (16). By ensuring that the corresponding value of condition (16) is not below the lower limit, astigmatism can be suppressed. By ensuring that the corresponding value of condition (16) is not above the upper limit, distortion aberrations can be suppressed. To obtain even better characteristics, the imaging lens more preferably satisfies the following condition (16-1), and even more preferably satisfies the following condition (16-2).

[0138] 1.55 < N1p < 2.5 (16)

[0139] 1.65 < N1p < 2.2 (16-1)

[0140] 1.7 < N1p < 1.95 (16-2)

[0141] Preferably, the first lens group G1 includes at least one negative lens. When the average refractive index of all the negative lenses in the first lens group G1 relative to the d-line is set to N1n, the imaging lens satisfies the following conditional expression (17). By ensuring that the corresponding value of conditional expression (17) is not below the lower limit, the generation of distortion aberrations can be suppressed. By ensuring that the corresponding value of conditional expression (17) is not above the upper limit, the generation of chromatic aberration can be suppressed. To obtain even better characteristics, the imaging lens more preferably satisfies the following conditional expression (17-1), and even more preferably satisfies the following conditional expression (17-2).

[0142] 1.43 < N1n < 2.1 (17)

[0143] 1.48 < N1n < 1.8 (17-1)

[0144] 1.5 < N1n < 1.7 (17-2)

[0145] When the average value of the dispersion coefficient of the d-line reference of all positive lenses of the second lens group G2, excluding the lens closest to the image side, is set to v2Fp, the imaging lens preferably satisfies the following condition (18). By ensuring that the corresponding value of condition (18) is not below the lower limit, the generation of axial chromatic aberration can be suppressed. By ensuring that the corresponding value of condition (18) is not above the upper limit, the refractive index of the positive lenses of the second lens group G2, excluding the lens closest to the image side, can be suppressed from becoming too low, thus suppressing the generation of spherical aberration. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (18-1), and even more preferably satisfies the following condition (18-2).

[0146] 35 < v2Fp < 85 (18)

[0147] 37 < v2Fp < 75 (18-1)

[0148] 40 < v2Fp < 61 (18-2)

[0149] When the average value of the dispersion coefficients of the d-line reference of all negative lenses in the second lens group G2, excluding the lens closest to the image side, is set to v2Fn, the imaging lens preferably satisfies the following condition (19). By ensuring that the corresponding value of condition (19) is not below the lower limit, the generation of axial secondary chromatic aberration can be suppressed. By ensuring that the corresponding value of condition (19) is not above the upper limit, it is beneficial to correct axial chromatic aberration. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (19-1), and even more preferably satisfies the following condition (19-2).

[0150] 28 < v2Fn < 55 (19)

[0151] 35 < v2Fn < 50 (19-1)

[0152] 37 < v2Fn < 45 (19-2)

[0153] Preferably, the lens closest to the object in the first lens group G1 and the second lens from the object in the first lens group G1 are negative lenses. When the focal length of the lens closest to the object in the first lens group G1 is set to fL1 and the focal length of the second lens from the object in the first lens group G1 is set to fL2, the imaging lens satisfies the following condition (20). By ensuring that the corresponding value of condition (20) is not below the lower limit, it is beneficial for wide-angle viewing. By ensuring that the corresponding value of condition (20) is not above the upper limit, it is beneficial for correcting distortion aberration and chromatic aberration. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (20-1), and even more preferably satisfies the following condition (20-2).

[0154] 0 < fL2 / fL1 < 1 (20)

[0155] 0.05 < fL2 / fL1 < 0.8 (20-1)

[0156] 0.1 < fL2 / fL1 < 0.7 (20-2)

[0157] When the focal length of the negative lens of the third lens group G3 is set to f3n, the focal length of the positive lens of the third lens group G3 is set to f3p, and the focal length of the imaging lens when focusing on an object at infinity is set to f, the imaging lens preferably satisfies the following condition (21). When both the negative and positive lenses of the third lens group G3 have strong refractive power, the absolute value of (1 / f3n-1 / f3p)×f increases. By ensuring that the corresponding value of condition (21) is not below the lower limit, the increase in chromatic aberration at high viewing angles can be suppressed. By ensuring that the corresponding value of condition (21) is not above the upper limit, it is beneficial to correct chromatic aberration and distortion aberration. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (21-1), and even more preferably satisfies the following condition (21-2).

[0158] -4<(1 / f3n-1 / f3p)×f<-1 (21)

[0159] -3.5<(1 / f3n-1 / f3p)×f<-1.2 (21-1)

[0160] -3<(1 / f3n-1 / f3p)×f<-1.3 (21-2)

[0161] When the lateral magnification of the second lens group G2 is set to β2 when focusing on an object at infinity, and the lateral magnification of the third lens group G3 is set to β3 when focusing on an object at infinity, the imaging lens preferably satisfies the following conditional expression (22). By ensuring that the corresponding value of conditional expression (22) is not below the lower limit, the amount of movement of the second lens group G2 during focusing can be shortened. By ensuring that the corresponding value of conditional expression (22) is not above the upper limit, variations in spherical aberration and image plane curvature during focusing can be suppressed. To obtain better characteristics, the imaging lens more preferably satisfies the following conditional expression (22-1), and even more preferably satisfies the following conditional expression (22-2).

[0162] 0.8 < (1-β2) 2 )×β3 2 <2.6 (22)

[0163] 1<(1-β2 2 )×β3 2 <2.4 (22-1)

[0164] 1.2 < (1-β2) 2 )×β3 2 <2.2 (22-2)

[0165] When the lateral magnification of the third lens group G3 is set to β3 when focusing on an object at infinity, the imaging lens preferably satisfies the following condition (23). By ensuring that the corresponding value of condition (23) is not below the lower limit, the amount of movement of the focusing group during focusing can be shortened. By ensuring that the corresponding value of condition (23) is not above the upper limit, variations in spherical aberration and image plane curvature during focusing can be suppressed. To obtain better characteristics, the imaging lens more preferably satisfies the following condition (23-1), and even more preferably satisfies the following condition (23-2).

[0166] 1.4 < β3 2 <3 (23)

[0167] 1.55<β3 2 <2.3 (23-1)

[0168] 1.7 < β3 2 <2.1 (23-2)

[0169] in addition, Figure 1 The example shown only includes the second lens group G2, but the focusing group can be configured in various ways. For example, it can be configured such that the first lens group G1 and the second lens group G2 move together along the optical axis Z during focusing. By moving the first lens group G1 and the second lens group G2 together during focusing, variations in spherical aberration and image plane curvature during focusing can be suppressed. Here, "moving together" means moving simultaneously by the same amount in the same direction.

[0170] As another approach to the focusing group, it can be configured such that during focusing, the first lens group G1 and the second lens group G2 change their spacing by moving along the optical axis Z. By moving the first lens group G1 and the second lens group G2 along different trajectories during focusing, variations in image plane curvature during focusing can be suppressed more effectively. Furthermore, when the first lens group G1 and the second lens group G2 change their spacing by moving along the optical axis Z during focusing, it is preferable that the movement of the first lens group G1 is less than the movement of the second lens group G2. In this case, it is advantageous to reduce the effective diameter of the lens in the first lens group G1.

[0171] The aperture St during focusing can be used in various ways. For example, the aperture St can be moved together with the second lens group G2 during focusing. In this case, the variation of the principal ray during focusing can be reduced, thus suppressing the variation of astigmatism during focusing. Alternatively, the aperture St can be moved together with the first lens group G1 or fixed together with the first lens group G1 during focusing. In this case, it is advantageous to reduce the effective diameter of the lens of the first lens group G1. Alternatively, the aperture St can be moved along the optical axis Z by changing the spacing between the first lens group G1 and the second lens group G2 during focusing. In this case, it is easy to suppress the variation of various aberrations during focusing evenly. Alternatively, the aperture St can also be moved as follows: Figure 1 As shown in the example, the image plane (S) is fixed during focusing. In this case, the structure can be simplified.

[0172] Next, feasible structural examples of the imaging lens of the present invention will be described. The following 1 to 6 structural examples all include, from the object side, a first lens group G1, an aperture St, a second lens group G2, and a third lens group G3.

[0173] The first structural example corresponds to the structure of Embodiment 1 described later. In the first structural example, the first lens group G1, from the object side to the image side, sequentially includes a negative meniscus lens with its convex surface facing the object side and a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side. The second lens group G2, from the object side to the image side, sequentially includes a combined lens formed by sequentially joining a biconvex lens and a biconcave lens from the object side, a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side, and a negative meniscus lens with its concave surface facing the object side. The third lens group G3, from the object side to the image side, sequentially includes a biconcave lens and a biconvex lens.

[0174] The second structural example corresponds to the structure of Embodiment 2 described later. The first lens group G1 of the second structural example has the same structure as the first lens group G1 of the first structural example. The second lens group G2 of the second structural example includes a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side, a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side, and a negative meniscus lens with its concave surface facing the object side. The third lens group G3 of the second structural example has the same structure as the third lens group G3 of the first structural example.

[0175] The third structural example corresponds to the structure of Embodiment 3 described later. In the third structural example, the first lens group G1, from the object side to the image side, sequentially includes a negative meniscus lens with its convex surface facing the object side, and a combined lens formed by sequentially joining the negative meniscus lens with its convex surface facing the object side and a biconvex lens from the object side. The second lens group G2 in the third structural example includes a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side, a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side, and a positive meniscus lens with its concave surface facing the object side. The third lens group G3 in the third structural example, from the object side to the image side, sequentially includes a negative meniscus lens with its concave surface facing the object side and a biconvex lens.

[0176] The fourth structural example corresponds to the structures of Embodiments 4 and 5 described later. The first lens group G1 of the fourth structural example has the same structure as the first lens group G1 of the first structural example. The second lens group G2 and the third lens group G3 of the fourth structural example have the same structure as the second lens group G2 and the third lens group G3 of the third structural example, respectively.

[0177] The fifth structural example corresponds to the structure of Embodiment 6 described later. The first lens group G1 and the second lens group G2 of the fifth structural example have the same structure as the first lens group G1 and the second lens group G2 of the third structural example. The third lens group G3 of the fifth structural example includes, from the object side to the image side, a negative meniscus lens with its concave surface facing the object side and a positive meniscus lens with its concave surface facing the object side.

[0178] The sixth structural example corresponds to the structure of Embodiment 7 described later. In the sixth structural example, the first lens group G1, from the object side to the image side, sequentially includes a positive meniscus lens with its convex surface facing the object side and a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side. The second lens group G2, from the object side to the image side, sequentially includes a combined lens formed by sequentially joining a biconcave lens and a biconvex lens from the object side, a combined lens formed by sequentially joining a negative meniscus lens with its concave surface facing the object side and a positive meniscus lens with its concave surface facing the object side, and a positive meniscus lens with its concave surface facing the object side. The third lens group G3, from the object side to the image side, sequentially includes a positive meniscus lens with its concave surface facing the object side and a biconcave lens.

[0179] Including structures related to conditional expressions, the above-mentioned preferred structures and implementable structures can be combined arbitrarily, and preferably selected appropriately according to the required specifications.

[0180] Next, an embodiment of the imaging lens of the present invention will be described.

[0181] [Example 1]

[0182] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 1 is shown. Figure 1The illustrated method and structure are as described above, therefore some repetitive descriptions are omitted here. The imaging lens of Embodiment 1, from the object side to the image side, includes a first lens group G1 with negative refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The first lens group G1, from the object side to the image side, includes three lenses: L11 to L13. The second lens group G2, from the object side to the image side, includes five lenses: L21 to L25. The third lens group G3, from the object side to the image side, includes two lenses: L31 to L32.

[0183] exist Figure 1 As an example, the example shown illustrates that the focusing group comprises only the second lens group G2. However, as mentioned above, it is also possible to configure the focusing group to move integrally with the first lens group G1 and the second lens group G2 during focusing, or to configure the first lens group G1 and the second lens group G2 to move by changing their intervals with each other during focusing. In these configurations, when focusing from an object at infinity to the nearest object, the focusing group moves towards the object side. This aspect related to the focusing group is also the same in the following embodiments.

[0184] Regarding the imaging lens of Example 1, basic lens data is shown in Table 1, specifications and variable surface spacing are shown in Table 2, and aspherical coefficients are shown in Table 3. In Table 1, the Sn column shows the surface numbering when the surface closest to the object side is designated as surface 1 and the numbering increases sequentially towards the image side; the R column shows the radius of curvature of each surface; and the D column shows the surface spacing on the optical axis between each surface and its image-side adjacent surface. The Nd column shows the refractive index of each component relative to the d-line; the vd column shows the dispersion coefficient of each component based on the d-line; and the θgF column shows the partial dispersion ratio between the g-line and F-line of each component. Regarding the lens, the material name and manufacturer's name of each lens are shown in the Material column by adding a period in the middle. The manufacturer's name is shown approximate. “OHARA” stands for OHARA INC., “HOYA” stands for HOYACorporation, “NHG” stands for Hubei Xinhua Optoelectronic Materials Co., Ltd., “CDGM” stands for Chengdu Guangming Optoelectronic Co., Ltd., and “SUMITA” stands for SUMITA OPTICAL GLASS, Inc.

[0185] In Table 1, the radius of curvature of the convex surface facing the object side is marked positive, and the radius of curvature of the convex surface facing the image side is marked negative. Table 1 also shows the aperture St and optical components PP. The term (St) is recorded along with the surface number in the surface number column corresponding to the aperture St. The value in the bottom column of D in Table 1 is the interval between the surface closest to the image side and the image plane Sim. In Table 1, the variable surface interval that changes during focusing is indicated by the notation DD[], with the object-side surface number of the interval marked in [] and recorded in column D.

[0186] Table 2 shows the values ​​for focal length f, back focal length Bf (equivalent to an air telemeter), F-number FNo., maximum full angle of view 2ωmax, and variable surface spacing. The (°) in the 2ωmax column indicates the unit as degrees. The values ​​shown in Table 2 are based on the d-line. In Table 2, the values ​​for an object at infinity and 400 mm are shown in the columns described as "infinity" and "400 mm," respectively. Object distance is the distance from the object to the optical axis of the lens surface closest to the object.

[0187] In Table 1, the surface numbers of aspherical surfaces are marked with an asterisk (*), and the paraxial radius of curvature is recorded in the radius of curvature column. In Table 3, the surface number of the aspherical surface is shown in the Sn column, and the aspherical coefficients for each aspherical surface are shown in the KA and Am (m = 3, 4, 5, ... 20) columns. The "E±n" (n: integer) values ​​for the aspherical coefficients in Table 3 represent "×10" ±n KA and Am are the aspheric coefficients in the aspheric formula expressed by the following equation.

[0188] Zd=C×h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+∑Am×h m

[0189] in,

[0190] Zd: Aspherical depth (the length of the perpendicular line from a point on the aspherical surface at height h to a plane tangent to the vertex of the aspherical surface and perpendicular to the optical axis);

[0191] h: Height (distance from the optical axis to the lens surface);

[0192] C: The reciprocal of the paraxial radius of curvature;

[0193] KA, Am: Aspheric coefficients

[0194] In aspherical form, ∑ represents the summation related to m.

[0195] In the data in each table, degrees are used as the unit for angles and millimeters as the unit for lengths. Optical systems can be used at both magnified and reduced scales, so other appropriate units may also be used. Furthermore, the values ​​are rounded to a specified number of decimal places in the tables shown below.

[0196] [Table 1]

[0197] Example 1

[0198] Sn R D Nd vd θgF Material *1 75.68710 1.854 1.51633 64.06 0.53345 L-BSL7.OHARA *2 19.28374 5.511 3 -38.47773 1.110 1.51742 52.43 0.55649 S-NSL36.OHARA 4 16.16828 5.385 1.87070 40.73 0.56825 TAFD32.HOYA 5 -202.09283 5.000 6 (St) ∞ DD[6] 7 22.64638 4.411 1.49700 81.54 0.53748 S-FPL51.OHARA 8 -11.76112 1.000 1.62588 35.71 0.58964 H-F13.NHG 9 83.51630 0.700 10 -183.75799 1.010 1.58144 40.75 0.57757 S-TIL25.OHARA 11 29.46568 5.132 1.88300 39.22 0.57295 H-ZLAF68N.CDGM 12 -21.06025 3.156 *13 -10.93318 2.008 1.80998 40.95 0.56644 K-VC89.SUMITA *14 -12.72668 DD

[14] 15 -25.00000 2.000 1.78472 25.68 0.61621 S-TIH11.OHARA 16 250.76231 3.000 17 88.23734 6.373 2.00100 29.13 0.59952 TAFD55.HOYA 18 -103.84217 13.696 19 ∞ 0.900 1.54763 54.98 0.55247 20 ∞ 1.200 21 ∞ 0.700 1.54763 54.98 0.55247 22 ∞ 0.600 1.54763 54.98 0.55247 23 ∞ 3.800 24 ∞ 1.000 1.49784 54.98 0.55000 25 ∞ 1.060

[0199] [Table 2]

[0200] Example 1

[0201] object distance Infinity 400mm f 30.919 30.566 Bf 21.845 19.482 FNo. 4.62 4.76 2ωmax(°) 90.6 88.2 DD[6] 3.956 2.763 DD

[14] 2.000 3.193

[0202] [Table 3]

[0203] Example 1

[0204] Sn 1 2 13 14 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 3.1098861E-04 3.7296493E-04 3.2495662E-04 2.9236238E-04 A5 0.0000000E+00 0.0000000E+00 -1.5636182E-05 -1.5516557E-05 A6 -3.0872307E-06 -1.9055929E-06 4.3641307E-06 3.6624541E-06 A7 0.0000000E+00 0.0000000E+00 -1.7115477E-08 8.7555789E-09 A8 2.3437272E-08 -3.2610975E-09 -2.4945541E-08 -1.5897468E-08 A9 0.0000000E+00 0.0000000E+00 -1.7751671E-09 -1.1569703E-09 A10 -6.1436321E-11 2.7348696E-10 -6.7738174E-12 -2.5650006E-11 A11 0.0000000E+00 0.0000000E+00 1.1487420E-11 3.7963003E-12 A12 -4.6510997E-13 1.8726414E-12 1.2409708E-12 6.0817614E-13 A13 0.0000000E+00 0.0000000E+00 8.0757576E-14 4.2272228E-14 A14 3.0960624E-15 -6.1675238E-14 -1.3812329E-16 1.3131510E-15 A15 0.0000000E+00 0.0000000E+00 -3.6933243E-16 -1.7015354E-16 A16 9.4249837E-18 1.1801651E-16 -5.2820560E-17 -2.8776897E-17 A17 0.0000000E+00 0.0000000E+00 -4.8233626E-18 -1.9776109E-18 A18 -1.2161288E-19 4.4461493E-18 -1.3493871E-19 4.9115316E-20 A19 0.0000000E+00 0.0000000E+00 -1.7661879E-21 2.3166274E-20 A20 2.7547312E-22 -2.2186314E-20 6.1362281E-21 -7.6602814E-22

[0205] Figure 2 The diagram shows the aberrations of the imaging lens in Example 1. Figure 2 In the image, from left to right, spherical aberration, astigmatism, distortion aberration, and magnification chromatic aberration are shown. Figure 2 In the diagram, the upper section marked "Infinity" shows the aberration diagrams for focusing on an object at infinity, and the lower section marked "400mm" shows the aberration diagrams for focusing on an object at a distance of 400mm. In the spherical aberration diagram, aberrations below the d-line, C-line, F-line, and g-line are shown with solid lines, long dashed lines, short dashed lines, and single-dot dashed lines, respectively. In the astigmatism diagram, aberrations below the d-line in the sagittal direction are shown with solid lines, and aberrations below the d-line in the meridional direction are shown with short dashed lines. In the distortion aberration diagram, aberrations below the d-line are shown with solid lines. In the magnification chromatic aberration diagram, aberrations below the C-line, F-line, and g-line are shown with long dashed lines, short dashed lines, and single-dot dashed lines, respectively. FNo. in the spherical aberration diagram represents the F-value, and ω in other aberration diagrams represents the half-angle of view. Figure 2 The values ​​of FNo. and ω corresponding to the upper end of the vertical axis of each graph are also shown.

[0206] Unless otherwise specified, the notation, meaning, recording method and illustration method of the data related to Embodiment 1 above are the same in the following embodiments, so repeated descriptions are omitted below.

[0207] [Example 2]

[0208] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 2 is shown. Figure 3The imaging lens of Embodiment 2, from the object side to the image side, comprises, in sequence, a first lens group G1 with positive refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The first lens group G1 comprises three lenses, L11 to L13, from the object side to the image side. The second lens group G2 comprises five lenses, L21 to L25, from the object side to the image side. The third lens group G3 comprises two lenses, L31 and L32, from the object side to the image side.

[0209] Regarding the imaging lens of Example 2, the basic lens data is shown in Table 4, the specifications and variable surface spacing are shown in Table 5, the aspherical coefficients are shown in Table 6, and the various aberrations are illustrated in Table 7. Figure 4 .exist Figure 4 In the middle section, the upper section shows the aberration diagrams for the state of focusing on an object at infinity, and the lower section shows the aberration diagrams for the state of focusing on an object at a distance of 400 mm.

[0210] [Table 4]

[0211] Example 2

[0212] Sn R D Nd vd θgF Material *1 68.18783 1.600 1.50670 70.54 0.53890 K-PG325.SUMITA *2 26.10177 5.044 3 -37.92101 1.008 1.57099 50.80 0.55887 S-BAL2.OHARA 4 15.40862 4.400 1.74100 52.64 0.54676 S-LAL61.OHARA 5 -33.34498 3.267 6 (St) ∞ DD[6] 7 -51.97967 0.510 1.54814 45.78 0.56859 S-TIL1.OHARA 8 19.96008 3.783 1.88300 39.22 0.57295 H-ZLAF68N.CDGM 9 -28.29840 0.674 10 -17.78837 0.810 1.64769 33.87 0.59124 K-SFLD2.SUMITA 11 20.78401 7.273 1.62041 60.29 0.54266 S-BSM16.OHARA 12 -17.85754 0.912 *13 -13.45927 1.800 1.80139 45.45 0.55814 M-TAF31.HOYA *14 -14.39669 DD

[14] 15 -24.42897 1.000 1.78880 28.43 0.60092 S-NBH58.OHARA 16 886.37116 3.076 17 116.51731 6.000 2.00100 29.13 0.59952 TAFD55.HOYA 18 -86.93889 8.800 19 ∞ 0.900 1.51680 64.20 0.53430 20 ∞ 0.820 21 ∞ 0.700 1.51680 64.20 0.53430 22 ∞ 0.600 1.51350 77.00 0.52020 23 ∞ 4.000 24 ∞ 1.000 1.51000 55.00 0.55105 25 ∞ 5.429

[0213] [Table 5]

[0214] Example 2

[0215] object distance Infinity 400mm f 35.913 34.706 Bf 21.162 18.066 FNo. 4.10 4.17 2ωmax(°) 83.0 82.2 DD[6] 5.868 4.166 DD

[14] 4.665 6.367

[0216] [Table 6]

[0217] Example 2

[0218] Sn 1 2 13 14 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 0.0000000E+00 A4 2.1230134E-04 2.3451300E-04 1.0207953E-04 1.1195837E-04 A5 -1.5711054E-05 4.9641260E-06 6.5367997E-05 4.6399935E-05 A6 5.6624754E-07 -7.8084655E-06 -1.5360901E-05 -1.0333753E-05 A7 2.3188763E-07 1.8540643E-06 -7.4820417E-07 -2.7077306E-07 A8 -8.7784656E-08 2.0838939E-08 9.4656756E-07 5.0610206E-07 A9 2.3845006E-09 -8.6573901E-08 -7.4419021E-08 -3.8266950E-08 A10 1.5876579E-09 6.7127573E-09 -2.2527813E-08 -1.0508806E-08 A11 -9.6944842E-11 1.8350339E-09 3.2642523E-09 1.4270063E-09 A12 -1.4462554E-11 -2.0919183E-10 2.4343580E-10 1.0173411E-10 A13 1.0875520E-12 -2.1446300E-11 -6.0302429E-11 -2.3589635E-11 A14 7.5832079E-14 2.9889778E-12 -5.0783413E-13 -1.9564324E-13 A15 -6.0075259E-15 1.4182869E-13 5.8816504E-13 2.0889575E-13 A16 -2.3508505E-16 -2.3089902E-14 -1.3842503E-14 -4.7319709E-15 A17 1.6726501E-17 -4.9644097E-16 -2.9620717E-15 -9.6409012E-16 A18 4.1585325E-19 9.3408529E-17 1.2577862E-16 3.9569910E-17 A19 -1.8753117E-20 7.1354964E-19 6.0511396E-18 1.8467718E-18 A20 -3.4119061E-22 -1.5542213E-19 -3.3279376E-19 -9.8835214E-20

[0219] [Example 3]

[0220] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 3 is shown. Figure 5 The imaging lens of Embodiment 3, from the object side to the image side, comprises, in sequence, a first lens group G1 with positive refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The first lens group G1 comprises three lenses L11 to L13 from the object side to the image side. The second lens group G2 comprises five lenses L21 to L25 from the object side to the image side. The third lens group G3 comprises two lenses L31 to L32 from the object side to the image side.

[0221] Regarding the imaging lens of Example 3, the basic lens data is shown in Table 7, the specifications and variable surface spacing are shown in Table 8, the aspherical coefficients are shown in Table 9, and the various aberrations are illustrated in Table 1. Figure 6 .exist Figure 6 In the middle section, the upper section shows the aberration diagrams for the state of focusing on an object at infinity, and the lower section shows the aberration diagrams for the state of focusing on an object at a distance of 400 mm.

[0222] [Table 7]

[0223] Example 3

[0224] Sn R D Nd vd θgF Material 1 250.30127 0.900 1.47047 66.88 0.53218 H-QK1.CDGM 2 25.14676 8.000 3 41.22340 1.310 1.77047 29.74 0.59514 NBFD29.HOYA 4 16.95976 3.208 1.88300 40.76 0.56679 S-LAH58.OHARA 5 -1504.42231 3.106 6 (St) ∞ DD[6] 7 -30.64661 0.510 1.51742 52.43 0.55649 S-NSL36.OHARA 8 27.10340 3.615 1.85883 30.00 0.59793 NBFD30.HOYA 9 -20.97398 0.500 10 -15.58132 0.860 1.68893 31.07 0.60041 S-TIM28.OHARA 11 16.39102 7.111 1.71300 53.87 0.54587 S-LAL8.OHARA 12 -20.00041 1.554 *13 -18.19793 3.105 1.77250 49.50 0.55193 M-TAF105.HOYA *14 -19.11171 DD

[14] 15 -21.52053 1.000 1.89286 20.36 0.63944 S-NPH4.OHARA 16 -2587.45558 1.954 17 485.01350 8.039 2.00069 25.46 0.61364 TAFD40.HOYA 18 -38.07825 9.410 19 ∞ 0.900 1.51680 64.20 0.53430 20 ∞ 0.820 21 ∞ 0.700 1.51680 64.20 0.53430 22 ∞ 0.600 1.51350 77.00 0.52020 23 ∞ 4.000 24 ∞ 1.000 1.51000 55.00 0.55105 25 ∞ 5.421

[0225] [Table 8]

[0226] Example 3

[0227] object distance Infinity 400mm f 35.983 34.897 Bf 21.765 18.669 FNo. 4.10 4.15 2ωmax(°) 78.8 79.8 DD[6] 5.804 3.978 DD

[14] 4.588 6.414

[0228] [Table 9]

[0229] Example 3

[0230] Sn 13 14 KA 1.0000000E+00 1.0000000E+00 A3 O.0000000E+00 0.0000000E+00 A4 9.0363217E-05 9.3545039E-05 A5 -7.0384815E-06 -2.9726223E-06 A6 1.7524377E-06 3.1360222E-07 A7 -4.5819132E-08 6.6339273E-08 A8 -9.1117551E-09 5.1917233E-10 A9 3.8980160E-10 -4.5372050E-10 A10 7.1063115E-11 -3.5781489E-11 A11 2.1201288E-12 2.0152910E-12 A12 -1.8380372E-12 2.1927496E-13 A13 5.5635889E-15 5.7705323E-15 A14 1.8104507E-14 9.1795658E-16 A15 1.0517148E-16 -1.6308789E-16 A16 -1.2383231E-16 -1.2699045E-17 A17 -3.1640418E-18 -2.6267555E-20 A18 8.1013368E-19 -4.8482345E-20 A19 -8.3410298E-21 2.6088371E-20 A20 -9.1911895E-22 -1.2550831E-21

[0231] [Example 4]

[0232] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 4 is shown. Figure 7 The imaging lens of Example 4, from the object side to the image side, comprises, in sequence, a first lens group G1 with positive refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The first lens group G1 comprises three lenses, L11 to L13, from the object side to the image side. The second lens group G2 comprises five lenses, L21 to L25, from the object side to the image side. The third lens group G3 comprises two lenses, L31 and L32, from the object side to the image side.

[0233] Regarding the imaging lens of Example 4, the basic lens data is shown in Table 10, the specifications and variable surface spacing are shown in Table 11, the aspherical coefficients are shown in Table 12, and the various aberrations are illustrated in Table 13. Figure 8 .exist Figure 8 In the middle section, the upper section shows the aberration diagrams for the state of focusing on an object at infinity, and the lower section shows the aberration diagrams for the state of focusing on an object at a distance of 400 mm.

[0234] [Table 10]

[0235] Example 4

[0236] Sn R D Nd vd θgF Material *1 49.99993 1.600 1.51742 52.43 0.55649 S-NSL36.OHARA *2 22.36296 7.578 3 -58.46285 1.010 1.57501 41.50 0.57672 S-TIL27.OHARA 4 19.28420 3.451 1.88300 40.80 0.56557 TAFD30.HOYA 5 -57.67722 2.950 6 (St) ∞ DD[6] 7 -59.43953 0.510 1.51742 52.43 0.55649 S-NSL36.OHARA 8 24.46458 3.361 1.88300 39.22 0.57295 H-ZLAF68N.CDGM 9 -32.34629 0.650 10 -19.53860 0.810 1.74077 27.76 0.60777 E-FD13.HOYA 11 30.06008 6.112 1.62041 60.29 0.54266 S-BSM16.OHARA 12 -18.78286 0.800 *13 -15.30009 1.800 1.80139 45.45 0.55814 M-TAF31.HOYA *14 -14.28645 DD

[14] 15 -19.08460 1.000 1.77047 29.74 0.59514 NBFD29.HOYA 16 -122.83559 2.695 17 160.84222 6.000 2.00069 25.46 0.61364 TAFD40.HOYA 18 -70.59491 8.800 19 ∞ 0.900 1.51680 64.20 0.53430 20 ∞ 0.820 21 ∞ 0.700 1.51680 64.20 0.53430 22 ∞ 0.600 1.51350 77.00 0.52020 23 ∞ 4.000 24 ∞ 1.000 1.51000 55.00 0.55105 25 ∞ 5.395

[0237] [Table 11]

[0238] Example 4

[0239] object distance Infinity 400mm f 35.949 34.626 Bf 21.128 18.055 FNo. 4.11 4.16 2ωmax(°) 82.0 82.0 DD[6] 5.918 4.191 DD

[14] 5.519 7.246

[0240] [Table 12]

[0241] Example 4

[0242] Sn 1 2 13 14 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 O.0000000E+00 A4 2.0999062E-04 1.4192221E-04 5.4122167E-05 1.5298021E-04 A5 -2.7473829E-05 5.0844648E-05 5.1837317E-05 -2.8693085E-05 A6 3.1727260E-06 -1.8623451E-05 -1.4216216E-05 7.4732375E-06 A7 4.8599971E-07 1.5011938E-06 -3.8959374E-07 7.4716003E-07 A8 -1.9001292E-07 6.3937765E-07 8.0832489E-07 -6.6889821E-07 A9 2.9828494E-09 -1.4457669E-07 -6.6007194E-08 7.0312915E-08 A10 3.2534144E-09 -6.4134959E-09 -1.6634399E-08 1.7918877E-08 A11 -1.6444086E-10 3.9091388E-09 2.2947320E-09 -3.5602975E-09 A12 -2.8547286E-11 -8.1862178E-11 1.4639356E-10 -1.6801059E-10 A13 1.9228545E-12 -5.3208663E-11 -3.1998566E-11 6.9632201E-11 A14 1.3970454E-13 2.6059185E-12 -2.3022186E-13 -6.6217174E-13 A15 -1.0728799E-14 3.9696681E-13 1.9790695E-13 -6.9114163E-13 A16 -3.7212134E-16 -2.5731582E-14 -3.3561948E-15 2.4986584E-14 A17 2.9759734E-17 -1.5498704E-15 -3.2867307E-16 3.4636730E-15 A18 4.6916729E-19 1.1648642E-16 2.9891045E-18 -1.7867123E-16 A19 -3.2989206E-20 2.4803655E-18 -9.5859101E-19 -6.9499850E-18 A20 -1.7234047E-22 -2.0473550E-19 8.0001532E-20 4.2783610E-19

[0243] [Example 5]

[0244] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 5 is shown. Figure 9 The imaging lens of Embodiment 5, from the object side to the image side, comprises, in sequence, a first lens group G1 with positive refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The first lens group G1 comprises three lenses, L11 to L13, from the object side to the image side. The second lens group G2 comprises five lenses, L21 to L25, from the object side to the image side. The third lens group G3 comprises two lenses, L31 and L32, from the object side to the image side.

[0245] Regarding the imaging lens of Example 5, the basic lens data is shown in Table 13, the specifications and variable surface spacing are shown in Table 14, the aspherical coefficients are shown in Table 15, and the various aberrations are illustrated in Table 16. Figure 10 .exist Figure 10 In the middle section, the upper section shows the aberration diagrams for the state of focusing on an object at infinity, and the lower section shows the aberration diagrams for the state of focusing on an object at a distance of 400 mm.

[0246] [Table 13]

[0247] Example 5

[0248] Sn R D Nd vd θgF Material *1 50.01787 1.600 1.51760 63.54 0.53369 K-PBK40.SUMITA *2 22.75246 7.266 3 -60.67412 1.010 1.58144 40.75 0.57757 S-TIL25.OHARA 4 21.10337 3.264 1.88300 40.80 0.56557 TAFD30.HOYA 5 -58.92870 2.950 6 (St) ∞ DD[6] 7 -75.12002 0.510 1.51823 58.90 0.54567 S-NSL3.OHARA 8 23.62088 3.248 1.88300 40.76 0.56679 S-LAH58.OHARA 9 -38.53773 0.650 10 -21.49582 0.810 1.71736 29.52 0.60483 S-TIH1.OHARA 11 25.99923 6.398 1.61800 63.33 0.54414 S-PHM52.OHARA 12 -18.96038 0.800 *13 -15.21758 1.800 1.80139 45.45 0.55814 M-TAF31.HOYA *14 -14.28632 DD

[14] 15 -18.22828 1.000 1.74000 28.30 0.60790 S-TIH3.OHARA 16 -154.87496 2.451 17 185.24806 6.330 2.00069 25.46 0.61364 TAFD40.HOYA 18 -61.73385 8.800 19 ∞ 0.900 1.51680 64.20 0.53430 20 ∞ 0.820 21 ∞ 0.700 1.51680 64.20 0.53430 22 ∞ 0.600 1.51350 77.00 0.52020 23 ∞ 4.000 24 ∞ 1.000 1.51000 55.00 0.55105 25 ∞ 5.411

[0249] [Table 14]

[0250] Example 5

[0251] object distance Infinity 400mm f 35.950 34.702 Bf 21.145 18.057 FNo. 4.11 4.16 2ωmax(°) 82.2 81.8 DD[6] 5.888 4.224 DD

[14] 5.786 7.450

[0252] [Table 15]

[0253] Example 5

[0254] Sn 1 2 13 14 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 0.0000000E+00 O.0000000E+00 A4 2.2374349E-04 1.4975617E-04 6.5638650E-05 1.6124693E-04 A5 -3.4501536E-05 5.0201891E-05 4.5652609E-05 -3.3975429E-05 A6 4.3234994E-06 -2.0178055E-05 -1.3582743E-05 8.6390652E-06 A7 6.1179190E-07 1.9533273E-06 2.9604040E-08 8.1547778E-07 A8 -2.3742041E-07 6.8391369E-07 6.9287336E-07 -7.4396116E-07 A9 3.1464875E-09 -1.7151938E-07 -7.3258786E-08 7.7247224E-08 A10 4.0670067E-09 -5.9181785E-09 -1.1342064E-08 1.9572770E-08 A11 -1.9274210E-10 4.5772780E-09 2.1031774E-09 -3.8507376E-09 A12 -3.6315756E-11 -1.2088424E-10 3.2108979E-11 -1.8158845E-10 A13 2.2760712E-12 -6.1888863E-11 -2.1965182E-11 7.4596261E-11 A14 1.8459980E-13 3.2939326E-12 9.5643551E-13 -7.0553697E-13 A15 -1.2746692E-14 4.5920743E-13 3.1112416E-14 -7.3503751E-13 A16 -5.3150816E-16 -3.1511204E-14 -7.3131880E-15 2.6544470E-14 A17 3.5441018E-17 -1.7835706E-15 9.2170881E-16 3.6617383E-15 A18 7.9651809E-19 1.4058482E-16 -1.7767576E-17 -1.8883113E-16 A19 -3.9371197E-20 2.8397477E-18 -4.5320398E-18 -7.3113230E-18 A20 -4.7519002E-22 -2.4486315E-19 2.1817791E-19 4.5013629E-19

[0255] [Example 6]

[0256] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 6 is shown. Figure 11The imaging lens of Embodiment 6, from the object side to the image side, comprises, in sequence, a first lens group G1 with positive refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with positive refractive power. The first lens group G1 comprises three lenses, L11 to L13, from the object side to the image side. The second lens group G2 comprises five lenses, L21 to L25, from the object side to the image side. The third lens group G3 comprises two lenses, L31 and L32, from the object side to the image side.

[0257] Regarding the imaging lens of Example 6, the basic lens data is shown in Table 16, the specifications and variable surface spacing are shown in Table 17, the aspherical coefficients are shown in Table 18, and the various aberrations are illustrated in Table 19. Figure 12 .exist Figure 12 In the middle section, the upper section shows the aberration diagrams for the state of focusing on an object at infinity, and the lower section shows the aberration diagrams for the state of focusing on an object at a distance of 400 mm.

[0258] [Table 16]

[0259] Example 6

[0260] Sn R D Nd vd θgF Material 1 250.56377 0.900 1.59282 68.62 0.54414 FCD515.HOYA 2 39.94603 8.000 3 87.91370 1.310 1.59551 39.24 0.58043 S-TIM8.OHARA 4 22.11687 2.700 1.88300 40.80 0.56557 TAFD30.HOYA 5 -1580.67256 2.950 6 (St) ∞ DD[6] 7 -24.41885 0.510 1.53172 48.84 0.56309 S-TIL6.OHARA 8 22.78484 3.725 1.88100 40.14 0.57010 TAFD33.HOYA 9 -21.52847 0.500 10 -15.97351 0.860 1.68893 31.07 0.60041 S-TIM28.OHARA 11 23.48310 5.668 1.72916 54.09 0.54490 S-LAL19.OHARA 12 -21.16307 1.425 *13 -18.26069 3.338 1.77250 49.50 0.55193 M-TAF105.HOYA *14 -19.44901 DD

[14] 15 -20.98862 1.000 1.72047 34.71 0.58350 S-NBH8.OHARA 16 -76.23784 5.697 17 -145.35396 6.744 1.90043 37.37 0.57668 TAFD37A.HOYA 18 -35.00906 9.410 19 ∞ 0.900 1.51680 64.20 0.53430 20 ∞ 0.820 21 ∞ 0.700 1.51680 64.20 0.53430 22 ∞ 0.600 1.51350 77.00 0.52020 23 ∞ 4.000 24 ∞ 1.000 1.51000 55.00 0.55105 25 ∞ 5.497

[0261] [Table 17]

[0262] Example 6

[0263] object distance Infinity 400mm f 36.045 35.513 Bf 21.841 18.662 FNo. 4.10 4.19 2ωmax(°) 81.2 81.6 DD[6] 6.068 3.877 DD

[14] 4.693 6.884

[0264] [Table 18]

[0265] Example 6

[0266] Sn 13 14 KA 1.0000000E+00 1.0000000E+00 A3 0.0000000E+00 0.0000000E+00 A4 9.1272949E-05 8.9835214E-05 A5 -8.3594616E-06 -3.2853942E-06 A6 1.8272657E-06 3.1360222E-07 A7 -2.5037120E-08 7.0031975E-08 A8 -1.0535938E-08 5.1917233E-10 A9 2.8801111E-10 -4.6813188E-10 A10 7.4076321E-11 -3.5781489E-11 A11 2.1201288E-12 2.0152910E-12 A12 -1.7045693E-12 2.1927496E-13 A13 5.5635889E-15 5.7705323E-15 A14 1.6168490E-14 9.1795658E-16 A15 1.0517148E-16 -1.6308789E-16 A16 -1.0689216E-16 -1.2699045E-17 A17 -3.1640418E-18 -2.6267555E-20 A18 7.2820091E-19 -4.8482345E-20 A19 -8.3410298E-21 2.6088371E-20 A20 -7.5094115E-22 -1.2550831E-21

[0267] [Example 7]

[0268] A cross-sectional view showing the structure and beam of the imaging lens of Embodiment 7 is shown. Figure 13 The imaging lens of Example 7, from the object side to the image side, comprises, in sequence, a first lens group G1 with positive refractive power, an aperture St, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The first lens group G1 comprises three lenses, L11 to L13, from the object side to the image side. The second lens group G2 comprises five lenses, L21 to L25, from the object side to the image side. The third lens group G3 comprises two lenses, L31 and L32, from the object side to the image side.

[0269] Regarding the imaging lens of Example 7, the basic lens data is shown in Table 19, the specifications and variable surface spacing are shown in Table 20, the aspherical coefficients are shown in Table 21, and the various aberrations are illustrated in Table 22. Figure 14 .exist Figure 14 In the middle section, the upper section shows the aberration diagrams for the state of focusing on an object at infinity, and the lower section shows the aberration diagrams for the state of focusing on an object at a distance of 400 mm.

[0270] [Table 19]

[0271] Example 7

[0272] Sn R D Nd vd θgF Material *1 74.86804 3.000 1.68893 31.16 0.60382 MC-FD80.HOYA *2 153.84549 1.860 3 -29.19165 1.010 1.68960 31.14 0.60319 E-FD80.HOYA 4 16.21723 4.072 1.89190 37.13 0.57813 S-LAH92.OHARA 5 -41.97201 3.419 6 (St) ∞ DD[6] 7 -20.18566 0.510 1.51680 64.20 0.53430 BSC7.HOYA 8 41.78736 3.316 2.00100 29.13 0.59952 TAFD55.HOYA 9 -21.62527 0.763 10 -14.49034 0.810 1.89286 20.36 0.63944 S-NPH4.OHARA 11 -117.23082 4.010 1.75500 52.32 0.54757 S-LAH97.OHARA 12 -17.85566 0.800 *13 -19.30623 1.800 1.80139 45.45 0.55814 M-TAF31.HOYA *14 -16.66196 DD

[14] 15 -40.00000 3.000 2.00100 29.13 0.59952 TAFD55-W.HOYA 16 -33.32334 2.000 17 -100.03883 1.830 1.83400 37.34 0.57908 NBFD10.HOYA 18 100.09741 8.800 19 ∞ 0.900 1.51680 64.20 0.53430 20 ∞ 0.820 21 ∞ 0.700 1.51680 64.20 0.53430 22 ∞ 0.600 1.51350 77.00 0.52020 23 ∞ 4.000 24 ∞ 1.000 1.51000 55.00 0.55105 25 ∞ 5.452

[0273] [Table 20]

[0274] Example 7

[0275] object distance Infinity 400mm f 36.930 34.826 Bf 21.186 17.997 FNo. 4.09 4.17 2ωmax(°) 72.6 73.2 DD[6] 6.375 3.809 DD

[14] 3.200 5.766

[0276] [Table 21]

[0277] Example 7

[0278] Sn 1 2 13 14 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 2.6316398E-19 3.8549411E-19 -2.2204460E-19 3.3365080E-19 A4 3.0240589E-05 -3.5425844E-06 1.4130437E-04 2.0592837E-04 A5 1.1269398E-05 5.0755326E-05 -5.7050819E-05 -9.8502688E-05 A6 -4.0210575E-06 -1.5744332E-05 -1.2928160E-06 1.8354871E-05 A7 4.5562139E-07 9.5875534E-07 6.5602234E-06 2.2541664E-06 A8 5.5290028E-08 5.2969172E-07 -9.4078194E-07 -1.0904248E-06 A9 -1.5318852E-08 -9.7339087E-08 -2.2301950E-07 3.9678002E-08 A10 4.6403527E-11 -5.2471699E-09 6.0086743E-08 2.4866054E-08 A11 2.1276716E-10 2.4495662E-09 1.4262077E-09 -2.4277604E-09 A12 -8.1149500E-12 -4.6855350E-11 -1.4687295E-09 -2.6344050E-10 A13 -1.6291961E-12 -3.0687303E-11 6.5799712E-11 4.2730775E-11 A14 8.7621071E-14 1.5550773E-12 1.6720696E-11 9.5313649E-13 A15 7.2343000E-15 2.1063077E-13 -1.5071571E-12 -3.7020625E-13 A16 -4.2896821E-16 -1.4613101E-14 -7.4361547E-14 5.1130555E-15 A17 -1.7558793E-17 -7.5695008E-16 1.2313001E-14 1.6078307E-15 A18 1.0083676E-18 6.2811756E-17 -8.7510339E-17 -5.4275846E-17 A19 1.8051701E-20 1.1135563E-18 -3.6223383E-17 -2.7721816E-18 A20 -9.0864012E-22 -1.0578392E-19 1.2259799E-18 1.2821233E-19

[0279] Tables 22 and 23 show the corresponding values ​​of conditional equations (1) to (23) for the imaging lenses of Examples 1 to 7. Examples 1 to 7 use the d-line as the reference wavelength. In Tables 22 and 23, except for some dispersion ratios, the values ​​are represented with the d-line as the reference.

[0280] [Table 22]

[0281]

[0282] [Table 23]

[0283]

[0284] As can be seen from the data above, the total length of the lens system of the imaging lenses in Examples 1 to 7 is shorter than the image size, resulting in a compact structure. Furthermore, the imaging lenses in Examples 1 to 7 achieve high optical performance by effectively correcting various aberrations.

[0285] Next, the imaging device according to the embodiments of the present invention will be described. Figure 15 and Figure 16 The diagram shows an external view of a camera 30, an imaging device according to an embodiment of the present invention. Figure 15 This is a stereoscopic view of camera 30 viewed from the front side. Figure 16This is a perspective view of the camera 30 as seen from the rear side. The camera 30 is a so-called mirrorless digital camera, which can be detachably fitted with an interchangeable lens 20. The interchangeable lens 20 is configured to include an imaging lens 1 according to an embodiment of the present invention housed within a lens barrel.

[0286] The camera 30 includes a camera body 31, and a shutter button 32 and a power button 33 are provided on the upper surface of the camera body 31. Furthermore, an operation unit 34, an operation unit 35, and a display unit 36 ​​are provided on the back of the camera body 31. The display unit 36 ​​can display the captured image and the image existing within the field of view before shooting.

[0287] A camera body 31 has a camera aperture for light from the subject to enter at the center of the front. A bayonet 37 is provided at the position corresponding to the camera aperture, and the interchangeable lens 20 is mounted on the camera body 31 via the bayonet 37.

[0288] The camera body 31 contains an imaging element such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) that outputs an image signal corresponding to the image of the subject formed by the interchangeable lens 20, a signal processing circuit that processes the image signal output from the imaging element to generate an image, and a recording medium for recording the generated image. In the camera 30, still images or moving images can be captured by pressing the shutter button 32, and the image data obtained through this capture is recorded in the aforementioned recording medium.

[0289] The above description, through examples and embodiments, illustrates the technology of the present invention. However, the technology of the present invention is not limited to the above examples and embodiments, and various modifications are possible. For example, the radius of curvature, interplanar spacing, refractive index, dispersion coefficient, and aspherical coefficient of each lens are not limited to the values ​​shown in the above embodiments, and other values ​​may be used.

[0290] Furthermore, the imaging device involved in the embodiments of the present invention is not limited to the examples described above. For example, it can also be configured as a camera other than a mirrorless camera, a film camera, a video camera, or other similar devices.

[0291] Symbol Explanation

[0292] 1-Imaging lens, 2-On-axis beam, 3-Brightness beam with maximum angle of view, 20-Interchangeable lens, 30-Camera, 31-Camera body, 32-Shutter button, 33-Power button, 34, 35-Operation unit, 36-Display unit, 37-Mount, G1-First lens group, G2-Second lens group, G3-Third lens group, L11~L13, L21~L25, L31~L32-Lens, PP-Optical components, Sim-Image plane, St-Aperture, Z-Optical axis.

Claims

1. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. The second lens group consists of two sets of conjoined lenses and a meniscus lens with its concave surface facing the object side, arranged sequentially from the object side to the image side. The third lens group consists of a negative lens and a positive lens.

2. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. The maximum half-angle of the imaging lens when focusing on an object at infinity is set to ωmax. The distance on the optical axis from the lens surface closest to the object side of the third lens group to the lens surface closest to the image side of the third lens group is defined as T3. When the focal length of the imaging lens is set to f while focusing on an object at infinity, ωmax is above 30 degrees. The imaging lens satisfies the following condition (8). 0.2<T3 / {f×tan(ωmax)<0.6 (8).

3. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. The third lens group consists of one negative lens and one positive lens. The paraxial radius of curvature of the object-side surface of the negative lens in the third lens group is set as R3nA. When the paraxial radius of curvature of the image-side surface of the negative lens in the third lens group is set to R3nB. The imaging lens satisfies the following condition (9). 0.2<(R3nB-R3nA) / (R3nB+R3nA)<2 (9).

4. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. The first lens group includes at least one negative lens and at least one positive lens. When the average value of the partial dispersion ratio between the g-line and F-line of all negative lenses in the first lens group is set as θ1n, and the average value of the partial dispersion ratio between the g-line and F-line of all positive lenses in the first lens group is set as θ1p, the following condition (13) is satisfied. -0.1<θ1n-θ1p<0.1 (13).

5. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. The lens closest to the object in the first lens group and the second lens from the object side of the first lens group are negative lenses. When the focal length of the lens closest to the object in the first lens group is set to fL1, and the focal length of the second lens from the object side of the first lens group is set to fL2, the following condition (20-1) is satisfied. 0.05<fL2 / fL1<0.8 (20-1).

6. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. When the lateral magnification of the second lens group is set to β2 when the object is focused at infinity, and the lateral magnification of the third lens group is set to β3 when the object is focused at infinity, the following condition (22) is satisfied. 0.8＜（1-β2 2 ）×β3 2 ＜2.6 （22）。 7. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. When the lateral magnification of the third lens group is set to β3 when the focus is on an object at infinity, the following condition (23) is satisfied. 1.4＜β3 2 ＜3 （23）。 8. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. With the distance along the optical axis from the lens surface closest to the object side of the third lens group to the lens surface closest to the image side of the third lens group defined as T3, and the back focal length of the imaging lens after air-converted distance defined as Bf, The imaging lens satisfies the following condition (10-2). 0.4<T3 / Bf<0.65 (10-2).

9. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, a second lens group with positive refractive power, and a third lens group, in sequence. During focusing, at least the second lens group moves along the optical axis, while the third lens group remains fixed relative to the image plane. The second lens group includes at least two negative lenses. When the average value of the dispersion coefficient of the d-line reference of all negative lenses in the second lens group, excluding the lens closest to the image side, is set to ν2Fn, The imaging lens satisfies the following condition (19-2). 37<ν2Fn<45 (19-2)。 10. The imaging lens according to any one of claims 1 to 9, wherein, During focusing, the first lens group and the second lens group move by changing their spacing from each other.

11. The imaging lens according to any one of claims 2 and 4 to 9, wherein, The third lens group consists of a negative lens and a positive lens.

12. The imaging lens according to any one of claims 1 to 9, wherein, When the focal length of the first lens group is set to f1, When the focal length of the second lens group is set to f2... The imaging lens satisfies the following condition (1). -0.5<f2 / f1<1 (1)。 13. The imaging lens according to any one of claims 1 to 9, wherein, The second lens group includes at least two positive lenses. A meniscus lens with its concave surface facing the object side is disposed on the image side of the second lens group.

14. The imaging lens according to any one of claims 1 to 9, wherein, Let the paraxial radius of curvature of the object-side surface of the lens closest to the image side of the second lens group be R2rA. When the paraxial radius of curvature of the image-side surface of the lens closest to the image side of the second lens group is set to R2rB, The imaging lens satisfies the following condition (2). -0.3<(R2rB-R2rA) / (R2rB+R2rA)<0.3 (2).

15. The imaging lens according to any one of claims 1 to 9, wherein, When the focal length of the second lens group is set to f2, When the focal length of the lens closest to the image side in the second lens group is set to f2R, The imaging lens satisfies the following condition (3). -0.4<f2 / f2R<0.6 (3).

16. The imaging lens according to any one of claims 1 to 9, wherein, The first lens group includes at least one negative lens and at least one positive lens.

17. The imaging lens according to any one of claims 1 to 9, wherein, The first lens group consists of two negative lenses and one positive lens, arranged sequentially from the object side to the image side.

18. The imaging lens according to claim 3, wherein, The absolute value of the radius of curvature of the object-side surface of the negative lens of the third lens group is smaller than the absolute value of the radius of curvature of the image-side surface.

19. The imaging lens according to claim 3, wherein, The third lens group consists of the negative lens and the positive lens arranged sequentially from the object side to the image side.

20. The imaging lens according to any one of claims 1 to 9, wherein, The focal length of the imaging lens when focusing on an object at infinity is set to f. When the focal length of the first lens group is set to f1... The imaging lens satisfies the following condition (4). -0.6 < f / f1 < 1.5 (4).

21. The imaging lens according to any one of claims 1 to 9, wherein, The focal length of the imaging lens when focusing on an object at infinity is set to f. When the focal length of the second lens group is set to f2... The imaging lens satisfies the following condition (5). 0.6 < f / f2 < 1.8 (5).

22. The imaging lens according to any one of claims 1 to 9, wherein, The focal length of the imaging lens when focusing on an object at infinity is set to f. When the focal length of the third lens group is set to f3... The imaging lens satisfies the following condition (6). -0.8 < f / f3 < 0.4 (6).

23. The imaging lens according to claim 3, wherein, When the focal length of the positive lens in the third lens group is set to f3p, When the focal length of the imaging lens is set to f while focusing on an object at infinity, The imaging lens satisfies the following condition (7). 0.5 < f3p / f < 3 (7).

24. The imaging lens according to any one of claims 1 to 9, wherein, When the paraxial radius of curvature of the surface of the second lens group from the image side to the image side of the second lens is set to R2sB, and the distance from the aperture to the optical axis from the surface of the second lens group from the image side to the image side of the second lens is set to S2sB, the following condition (11) is satisfied. 0.7<-R2sB / S2sB<1.7 (11).

25. The imaging lens according to any one of claims 1 to 9, wherein, The first lens group includes at least one negative lens and at least one positive lens. When the average value of the dispersion coefficients of the d-line reference of all negative lenses in the first lens group is set to ν1n, and the average value of the dispersion coefficients of the d-line reference of all positive lenses in the first lens group is set to ν1p, the following condition (12) is satisfied. -10<ν1n-ν1p<40 (12).

26. The imaging lens according to claim 3, wherein, When the refractive index of the positive lens of the third lens group relative to the d-line is set to N3p, the following condition (14) is satisfied. 1.6 < N3p < 2.5 (14).

27. The imaging lens according to claim 3, wherein, When the refractive index of the negative lens of the third lens group relative to the d line is set to N3n, the following condition (15) is satisfied. 1.55 < N3n < 2.5 (15).

28. The imaging lens according to any one of claims 1 to 9, wherein, The first lens group includes at least one positive lens. When the average refractive index of all positive lenses in the first lens group relative to the d line is set to N1p, the following condition (16) is satisfied. 1.55 < N1p < 2.5 (16).

29. The imaging lens according to any one of claims 1 to 9, wherein, The first lens group includes at least one negative lens. When the average refractive index of all negative lenses in the first lens group relative to the d line is set to N1n, the following condition (17) is satisfied. 1.43 < N1n < 2.1 (17).

30. The imaging lens according to any one of claims 1 to 9, wherein, When the average value of the dispersion coefficients of the d-line reference of all positive lenses in the second lens group, except for the lens on the image side of the second lens group, is set to ν2Fp, the following condition (18) is satisfied. 35<ν2Fp<85 (18)。 31. The imaging lens according to claim 3, wherein, When the focal length of the negative lens of the third lens group is set to f3n, the focal length of the positive lens of the third lens group is set to f3p, and the focal length of the imaging lens in the state of focusing on an object at infinity is set to f, the following condition (21) is satisfied. -4<(1 / f3n-1 / f3p)×f<-1 (21).

32. The imaging lens according to any one of claims 1 to 9, wherein, During focusing, the first lens group is fixed relative to the image plane.

33. The imaging lens according to any one of claims 1 to 9, wherein, During focusing, the first lens group and the second lens group move as a whole.

34. The imaging lens according to claim 12, wherein, The imaging lens satisfies the following condition (1-1). -0.3<f2 / f1<0.9 (1-1).

35. The imaging lens according to claim 12, wherein, The imaging lens satisfies the following condition (1-2). -0.2<f2 / f1<0.8 (1-2).

36. The imaging lens according to claim 14, wherein, The imaging lens satisfies the following condition (2-1). -0.15<(R2rB-R2rA) / (R2rB+R2rA)<0.15 (2-1).

37. The imaging lens according to claim 14, wherein, The imaging lens satisfies the following condition (2-2). -0.1<(R2rB-R2rA) / (R2rB+R2rA)<0.1 (2-2).

38. The imaging lens according to claim 15, wherein, The imaging lens satisfies the following condition (3-1). -0.3<f2 / f2R<0.5 (3-1).

39. The imaging lens according to claim 15, wherein, The imaging lens satisfies the following condition (3-2). -0.2<f2 / f2R<0.4 (3-2).

40. The imaging lens according to claim 20, wherein, The imaging lens satisfies the following condition (4-1). -0.4<f / f1<1.1 (4-1).

41. The imaging lens according to claim 20, wherein, The imaging lens satisfies the following condition (4-2). -0.2<f / f1<0.88 (4-2).

42. The imaging lens according to claim 21, wherein, The imaging lens satisfies the following condition (5-1). 0.8 < f / f2 < 1.6 (5-1).

43. The imaging lens according to claim 21, wherein, The imaging lens satisfies the following condition (5-2). 0.9 < f / f2 < 1.4 (5-2).

44. The imaging lens according to claim 22, wherein, The imaging lens satisfies the following condition (6-1). -0.6<f / f3<0.2 (6-1).

45. The imaging lens according to claim 22, wherein, The imaging lens satisfies the following condition (6-2). -0.5<f / f3<0.1 (6-2).

46. ​​The imaging lens according to claim 23, wherein, The imaging lens satisfies the following condition (7-1). 0.6 < f3p / f < 2 (7-1).

47. The imaging lens according to claim 23, wherein, The imaging lens satisfies the following condition (7-2). 0.8<f3p / f<1.8 (7-2).

48. The imaging lens according to claim 2, wherein, The imaging lens satisfies the following condition (8-1). 0.24<T3 / {f×tan(ωmax)}<0.5 (8-1).

49. The imaging lens according to claim 2, wherein, The imaging lens satisfies the following condition (8-2). 0.26<T3 / {f×tan(ωmax)<0.45 (8-2).

50. The imaging lens according to claim 3, wherein, The imaging lens satisfies the following condition (9-1). 0.4<(R3nB-R3nA) / (R3nB+R3nA)<1.6 (9-1).

51. The imaging lens according to claim 3, wherein, The imaging lens satisfies the following condition (9-2). 0.5<(R3nB-R3nA) / (R3nB+R3nA)<1.4 (9-2).

52. The imaging lens according to claim 24, wherein, The imaging lens satisfies the following condition (11-1). 0.8<-R2sB / S2sB<1.5 (11-1).

53. The imaging lens according to claim 24, wherein, The imaging lens satisfies the following condition (11-2). 0.85<-R2sB / S2sB<1.4 (11-2).

54. The imaging lens according to claim 25, wherein, The imaging lens satisfies the following condition (12-1). -4<ν1n-ν1p<30 (12-1).

55. The imaging lens according to claim 25, wherein, The imaging lens satisfies the following condition (12-2). 0<ν1n-ν1p<19 (12-2).

56. The imaging lens according to claim 4, wherein, The imaging lens satisfies the following condition (13-1). -0.06<θ1n-θ1p<0.06 (13-1).

57. The imaging lens according to claim 4, wherein, The imaging lens satisfies the following condition (13-2). -0.04<θ1n-θ1p<0.05 (13-2).

58. The imaging lens according to claim 26, wherein, The imaging lens satisfies the following condition (14-1). 1.8 < N3p < 2.2 (14-1).

59. The imaging lens according to claim 26, wherein, The imaging lens satisfies the following condition (14-2). 1.85<N3p<2.1 (14-2).

60. The imaging lens according to claim 27, wherein, The imaging lens satisfies the following condition (15-1). 1.6 < N3n < 2.2 (15-1).

61. The imaging lens according to claim 27, wherein, The imaging lens satisfies the following condition (15-2). 1.65<N3n<1.95 (15-2).

62. The imaging lens according to claim 28, wherein, The imaging lens satisfies the following condition (16-1). 1.65<N1p<2.2 (16-1).

63. The imaging lens according to claim 28, wherein, The imaging lens satisfies the following condition (16-2). 1.7<N1p<1.95 (16-2).

64. The imaging lens according to claim 29, wherein, The imaging lens satisfies the following condition (17-1). 1.48<N1n<1.8 (17-1).

65. The imaging lens according to claim 29, wherein, The imaging lens satisfies the following condition (17-2). 1.5 < N1n < 1.7 (17-2).

66. The imaging lens according to claim 30, wherein, The imaging lens satisfies the following condition (18-1). 37<ν2Fp<75 (18-1)。 67. The imaging lens according to claim 30, wherein, The imaging lens satisfies the following condition (18-2). 40<ν2Fp<61 (18-2)。 68. The imaging lens according to claim 5, wherein, The imaging lens satisfies the following condition (20-2). 0.1<fL2 / fL1<0.7 (20-2).

69. The imaging lens according to claim 31, wherein, The imaging lens satisfies the following condition (21-1). -3.5<(1 / f3n-1 / f3p)×f<-1.2 (21-1).

70. The imaging lens according to claim 31, wherein, The imaging lens satisfies the following condition (21-2). -3<(1 / f3n-1 / f3p)×f<-1.3 (21-2).

71. The imaging lens according to claim 6, wherein, The imaging lens satisfies the following condition (22-1). 1＜（1-β2 2 ）×β3 2 ＜2.4 （22-1）。 72. The imaging lens according to claim 6, wherein, The imaging lens satisfies the following condition (22-2). 1.2＜（1-β2 2 ）×β3 2 ＜2.2 （22-2）。 73. The imaging lens according to claim 7, wherein, The imaging lens satisfies the following condition (23-1). 1.55＜β3 2 ＜2.3 （23-1）。 74. The imaging lens according to claim 7, wherein, The imaging lens satisfies the following condition (23-2). 1.7＜β3 2 ＜2.1 （23-2）。 75. A camera device comprising an imaging lens according to any one of claims 1 to 74.

Images