Imaging lens and imaging device

Abstract

The invention provides an imaging lens which is small in F value, small in size and capable of maintaining good optical performance and an imaging device provided with the imaging lens. The imaging lens includes, in order from an object side to an image side, a first lens group, an aperture, and a second lens group. During focusing, the whole imaging lens moves, or a part of the first lens group, the diaphragm, and the second lens group moves. The imaging lens satisfies the conditional expression 0.1 < f / f1 < 1.5, where f is the focal length of the imaging lens in a state in which the imaging lens is focused on an object at infinity, and f1 is the focal length of the first lens group.

Description

Technical Field

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

[0002] Previously, as an imaging lens that can be used in imaging devices such as digital cameras, there is a known imaging optical system as described in Patent Document 1.

[0003] Patent Document 1: International Publication No. 2014 / 034040

[0004] There is a need for imaging lenses that are small in size, have a low F-number, and maintain good optical performance. These requirements are increasing year by year. Summary of the Invention

[0005] The present invention provides an imaging lens with a small F-number, a small size, and good optical performance, and a camera device having the imaging lens.

[0006] One aspect of the present invention is an imaging lens, which includes a first lens group, an aperture, and a second lens group in sequence from the object side to the image side. During focusing, the imaging lens moves as a whole, or a portion of the first lens group, the aperture, and the second lens group moves. 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 is set to f1, the imaging lens satisfies the following conditional expression (1):

[0007] 0.1 <f / f1<1.5(1)。

[0008] The first lens group includes at least one positive lens. When the focal length of the positive lens with the strongest optical power among the positive lenses included in the first lens group is set to fp1, the imaging lens of the above method preferably satisfies the following condition (2):

[0009] 0.1 <f / fp1<4(2)。

[0010] The first lens group includes at least one positive lens and at least one negative lens. When the focal length of the positive lens closest to the object in the first lens group is set to fp1F and the focal length of the negative lens with the strongest optical power in the first lens group is set to fn1, the imaging lens of the above-described manner preferably satisfies the following condition (3):

[0011] 0.3 <fp1F / |fn1|<6 (3)。

[0012] The second lens group includes at least one negative lens. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group is set to fn2, the imaging lens of the above method preferably satisfies the following condition (4):

[0013] 0.3 <f / |fn2|<6 (4)。

[0014] The first lens group includes at least one positive lens and at least one negative lens. When the focal length of the positive lens with the strongest optical power among the positive lenses included in the first lens group is set to fp1, and the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1, the imaging lens of the above-described manner preferably satisfies the following conditional expression (5):

[0015] 0.15 <fp1 / |fn1|<6 (5)。

[0016] The first lens group includes at least one positive lens. When the radius of curvature of the object-side surface of the positive lens with the highest optical power among the positive lenses included in the first lens group is set to Rf, and the radius of curvature of the image-side surface of the positive lens with the highest optical power among the positive lenses included in the first lens group is set to Rr, the imaging lens of the above-described manner preferably satisfies the following conditional expression (6):

[0017] 0.05<(Rr+Rf) / (Rr-Rf)<6 (6).

[0018] The first lens group includes at least one positive lens. When the focal length of the positive lens with the strongest optical power among the positive lenses included in the first lens group is set to fp1, the imaging lens of the above method preferably satisfies the following conditional expression (7):

[0019] 0.3 <f1 / fp1<4.5 (7)。

[0020] The first lens group includes at least one negative lens, and the second lens group includes at least one negative lens. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1, and the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group is set to fn2, the imaging lens of the above-described manner preferably satisfies the following conditional expression (8):

[0021] 0.1 <fn1 / fn2<6 (8)。

[0022] The first lens group includes at least one negative lens. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1, the imaging lens of the above method preferably satisfies the following condition (9):

[0023] 0.2 <f / |fn1|<5(9)。

[0024] Preferably, the lens surface of the first lens group closest to the image is concave, and the lens surface of the second lens group closest to the object is concave.

[0025] The first lens group preferably includes two or more positive lenses.

[0026] Preferably, a positive meniscus lens with its convex surface facing the object side is disposed on the object side of the first lens group.

[0027] The first lens group includes at least one positive lens. When the refractive index of the positive lens closest to the object in the first lens group is set to Np1F relative to the d-line, the imaging lens of the above manner preferably satisfies the following condition (10):

[0028] 1.5 <Np1F<2.03 (10)。

[0029] The second lens group preferably includes at least one lens surface with a pole. The pole is a point on the lens surface other than on the optical axis, and the tangent of the lens surface at the pole intersects the optical axis perpendicularly.

[0030] The second lens group consists of a front part and a rear part, arranged sequentially from the object side to the image side.

[0031] It can be configured such that, during focusing, the first lens group, the aperture, and the front part group move as a whole, while the rear part group is fixed relative to the image plane.

[0032] The rear portion preferably includes one or more lenses, each lens comprising at least one lens surface with a pole. The pole is a point on the lens surface other than on the optical axis, and the tangent of the lens surface at the pole intersects the optical axis perpendicularly.

[0033] The rear portion preferably includes two or more lenses, each lens including at least one lens surface with a pole.

[0034] When the sum of the air gaps on the optical axis within the rear section group is set to D2Rair, and the distance on the optical axis from the lens surface closest to the object side of the rear section group to the lens surface closest to the image side of the rear section group is set to D2R, the imaging lens of the above manner preferably satisfies the following condition (11):

[0035] 0≤D2Rair / D2R<0.45(11).

[0036] When focusing on an object at infinity, the distance along the optical axis from the lens surface closest to the object in the first lens group to the lens surface closest to the image in the rear lens group is set to DT.

[0037] The imaging lens described above preferably satisfies the following condition (12):

[0038] 0.05 <D2R / DT<0.5(12)。

[0039] Another aspect of the present invention is a camera device having an imaging lens as described above.

[0040] 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 optical 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.

[0041] In this specification, "a group with positive optical power" means that the group as a whole has positive optical power. Similarly, "a group with negative optical power" means that the group as a whole has negative optical power. "A lens with positive optical power" has the same meaning as "positive lens." "A lens with negative optical power" has the same meaning as "negative lens." In this specification, "a group" is not limited to a structure that includes multiple lenses; it can also be a structure that includes only one lens.

[0042] The "focal length" used in the conditional expressions is the paraxial focal length. Unless otherwise specified, the "distance on the optical axis" used in the conditional expressions is the geometric distance. Unless otherwise specified, the values ​​used in the conditional expressions are those relative to the d-line when focusing on an object at infinity.

[0043] Unless otherwise specified, the signs for radii of curvature, optical power, and surface shapes related to lenses including aspherical surfaces shall use the signs for paraxial radii of curvature, optical power, and surface shapes. Regarding the sign of the radii of curvature, the sign of the radii of curvature of the convex surface facing the object side shall be positive, and the sign of the radii of curvature of the convex surface facing the image side shall be negative.

[0044] The “d-line”, “C-line” and “F-line” described in this specification are bright lines. The wavelength of the d-line is considered to be 587.56 nm (nanometers), the wavelength of the C-line is considered to be 656.27 nm (nanometers), and the wavelength of the F-line is considered to be 486.13 nm (nanometers).

[0045] Invention Effects

[0046] According to the present invention, it is possible to provide an imaging lens with a small F-number, a small size, and good optical performance, and an imaging device having the imaging lens. Attached Figure Description

[0047] Figure 1 This is a cross-sectional view showing the structure of an imaging lens according to an embodiment corresponding to the imaging lens of Example 1.

[0048] Figure 2 It means Figure 1 The structure of the imaging lens in various states and the cross-sectional view of the beam.

[0049] Figure 3 It is a diagram used to illustrate poles.

[0050] Figure 4 It is a diagram used to illustrate the location of the maximum effective diameter.

[0051] Figure 5 This is a diagram of the aberrations of the imaging lens in Example 1.

[0052] Figure 6 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 2.

[0053] Figure 7 This is a diagram of the aberrations of the imaging lens in Example 2.

[0054] Figure 8 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 3.

[0055] Figure 9 This is a diagram of the aberrations of the imaging lens in Example 3.

[0056] Figure 10 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 4.

[0057] Figure 11 This is a diagram of the aberrations of the imaging lens in Example 4.

[0058] Figure 12 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 5.

[0059] Figure 13 This is a diagram of the aberrations of the imaging lens in Example 5.

[0060] Figure 14 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 6.

[0061] Figure 15 This is a diagram of the aberrations of the imaging lens in Example 6.

[0062] Figure 16 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 7.

[0063] Figure 17 This is a diagram of the aberrations of the imaging lens in Example 7.

[0064] Figure 18 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 8.

[0065] Figure 19 This is a diagram of the aberrations of the imaging lens in Example 8.

[0066] Figure 20This is a cross-sectional view showing the structure of the imaging lens in Embodiment 9.

[0067] Figure 21 This is a diagram of the aberrations of the imaging lens in Example 9.

[0068] Figure 22 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 10.

[0069] Figure 23 This is a diagram of the aberrations of the imaging lens in Example 10.

[0070] Figure 24 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 11.

[0071] Figure 25 This is a diagram of the aberrations of the imaging lens in Example 11.

[0072] Figure 26 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 12.

[0073] Figure 27 This is a diagram of the aberrations of the imaging lens in Example 12.

[0074] Figure 28 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 13.

[0075] Figure 29 This is a diagram of the aberrations of the imaging lens in Example 13.

[0076] Figure 30 This is a cross-sectional view showing the structure of the imaging lens in Embodiment 14.

[0077] Figure 31 This is a diagram of the aberrations of the imaging lens in Example 14.

[0078] Figure 32 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 15.

[0079] Figure 33 This is a diagram of the aberrations of the imaging lens in Example 15.

[0080] Figure 34 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 16.

[0081] Figure 35 This is a diagram of the aberrations of the imaging lens in Example 16.

[0082] Figure 36 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 17.

[0083] Figure 37This is a diagram of the aberrations of the imaging lens in Example 17.

[0084] Figure 38 This is a cross-sectional view showing the structure of the imaging lens of Embodiment 18.

[0085] Figure 39 This is a diagram of the aberrations of the imaging lens in Example 18.

[0086] Figure 40 This is a perspective view of the front side of a camera device according to one embodiment.

[0087] Figure 41 This is a perspective view of the rear side of a camera device according to one embodiment.

[0088] Symbol Explanation

[0089] 1-Imaging lens, 20-Interchangeable lens, 30-Camera, 31-Camera body, 32-Shutter button, 33-Power button, 34-Operation unit, 35-Operation unit, 36-Display unit, 37-Mount, 38-Imaging element, ED-Effective diameter, G1-First lens group, G2-Second lens group, G2F-Front side group, G2R-Rear side group, L11~L28-Lens, Lx-Lens, P-Pole, Px-Position of maximum effective diameter, Sim-Image plane, St-Aperture stop, Tp-Cut plane, Xa-On-axis beam, Xb-Off-axis beam, Xb1-Ray, Z-Optical axis. Detailed Implementation

[0090] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0091] exist Figure 1 A cross-sectional view of the structure of an imaging lens according to an embodiment of the present invention is shown. Figure 2 In, it is shown Figure 1 The structure of the imaging lens and a cross-sectional view of the beam. In Figure 2 In the image, the upper section marked "infinity" shows the state of focusing on an object at infinity, while the lower section marked "close distance" shows the state of focusing on an object at close distance. Figure 2 The lower segment represents a state where the absolute value of the magnification is 0.15x. Figure 2 In the diagram, an on-axis beam focused on an object at infinity and a beam with its maximum half-angle are shown, as well as an on-axis beam focused on a nearby object and a beam with its maximum half-angle. Figure 1 and Figure 2 In the image, the left side is the object side, and the right side is the image side. Figure 1 and Figure 2 The example shown corresponds to the imaging lens of Embodiment 1 described later. The following mainly refers to... Figure 1Please provide an explanation.

[0092] The imaging lens of this invention is a fixed-focus optical system, which comprises, along the optical axis Z from the object side to the image side, a first lens group G1, an aperture stop St, and a second lens group G2. During focusing, the imaging lens moves as a whole, or during focusing, a portion of the first lens group G1, the aperture stop St, and the second lens group G2 moves, while the remaining portions of the second lens group G2 remain fixed relative to the image plane Sim. By adopting this focusing mechanism, the overall optical length can be shortened.

[0093] As an example, Figure 1 The imaging lens group is configured as follows. The first lens group G1 consists of three lenses, L11 to L13, arranged sequentially from the object side to the image side. The second lens group G2 consists of five lenses, L21 to L25, arranged sequentially from the object side to the image side. Figure 1 The aperture stop St indicates the position along the optical axis, not its size or shape. This method of illustrating the aperture stop St is also used in other cross-sectional views.

[0094] exist Figure 1 In the example, during focusing, the imaging lens moves as a single unit. Furthermore, "moves as a single unit" in this specification means moving simultaneously by the same amount in the same direction. Figure 1 The brackets and arrows below the imaging lens indicate the lens that moves and its direction of movement when focusing from an object at infinity to a closer object.

[0095] The first lens group G1 preferably includes two or more positive lenses. This configuration is advantageous for correcting spherical aberration.

[0096] Preferably, a positive meniscus lens with its convex surface facing the object side is positioned on the object side of the first lens group G1. This configuration is advantageous for correcting spherical aberration.

[0097] Preferably, the lens surface of the first lens group G1, closest to the image, is concave, and the lens surface of the second lens group G2, closest to the object, is concave. With this configuration, the symmetry of the optical system with respect to the aperture stop St is improved, which is beneficial for the proper correction of various aberrations.

[0098] The second lens group G2 preferably includes at least one lens surface with a pole. With this configuration, it is easy to correct various aberrations well while achieving a significant reduction in the size of the optical system.

[0099] Furthermore, the term "lens surface" in this specification is not limited to the air-contact surface, but also includes the boundary surfaces of lenses that are not in contact with air and are made of different materials, such as the bonding surface of a joint lens. Moreover, the term "lens surface" in this specification refers to the surface of a lens through which light rays used for imaging pass.

[0100] In this specification, "pole" refers to a point on the lens surface other than the optical axis, and the tangent of the lens surface at the pole intersects the optical axis Z perpendicularly. Figure 3 The section shown includes the optical axis Z. Figure 1 An enlarged view of the aperture stop St of the imaging lens and the second lens group G2. As an example, in... Figure 3 The image shows the pole P of the lens surface on the image side of lens L23, and the tangent plane Tp of this lens surface at pole P is shown in dashed lines. The tangent plane Tp intersects the optical axis Z perpendicularly. Furthermore, Figure 3 The second lens group G2 has poles in addition to the pole P shown in the figure, but the symbols for the other poles are omitted.

[0101] The imaging lens of the present invention preferably includes at least one of the first to fourth aspherical lenses described below as a lens having a pole.

[0102] The first aspherical lens is a lens having at least one lens surface with a convex shape facing the object side in the paraxial region and having a pole. With the first aspherical lens, it is easy to correct off-axis aberrations while miniaturizing the optical system without worsening spherical aberrations.

[0103] The second aspherical lens is a lens having at least one lens surface with a concave shape facing the object side in the paraxial region and having a pole. The second aspherical lens helps to suppress image plane curvature while reducing the incident angle of the off-axis principal ray onto the image plane Sim.

[0104] The third aspherical lens is a lens having at least one lens surface with a convex shape facing the image side in the paraxial region and having a pole. The third aspherical lens facilitates the correction of off-axis aberrations while simultaneously enabling miniaturization of the optical system.

[0105] The fourth aspherical lens is a lens having at least one lens surface with a concave shape facing the image side in the paraxial region and having a pole. Astigmatism can be easily corrected with the fourth aspherical lens.

[0106] Next, the preferred structure of the imaging lens of the present invention related to the conditional expressions will be described. In the following description of the conditional expressions, to avoid redundancy, the same notation will be used for the same definition of the same part, and repeated descriptions of the notation will be omitted. Furthermore, in the following, to avoid redundancy, "the imaging lens of the present invention" will also be simply referred to as "imaging lens".

[0107] Furthermore, in this specification, "positive lens" and "negative lens" refer to a single lens that is a constituent element. For example, in the following description, when the first lens group G1 includes a joint lens and that joint lens includes a positive lens, "the positive lens included in the first lens group G1" does not refer to the joint lens, but rather to a single positive lens within the joint lens. Similarly, when the first lens group G1 includes a joint lens and that joint lens includes a negative lens, "the negative lens included in the first lens group G1" does not refer to the joint lens, but rather to a single negative lens within the joint lens. These cases remain the same even if the first lens group G1 is replaced with the second lens group G2.

[0108] The imaging lens preferably satisfies the following condition (1). Here, the focal length of the imaging lens in the state of focusing on an object at infinity is set to f. The focal length of the first lens group G1 is set to f1. By ensuring that the corresponding value of condition (1) is not below the lower limit, the positive optical power of the first lens group G1 can be ensured, which is beneficial for shortening the total length of the lens. By ensuring that the corresponding value of condition (1) is not above the upper limit, the positive optical power of the first lens group G1 will not become too strong, which makes it easy to suppress spherical aberration and astigmatism. By easily suppressing spherical aberration, it is easy to reduce the F-value.

[0109] 0.1 <f / f1<1.5(1)

[0110] To obtain better characteristics, the lower limit of conditional expression (1) is more preferably set to 0.19, further preferably 0.24, further preferably 0.29, further preferably 0.34, further preferably 0.37, and further preferably 0.39. To obtain better characteristics, the upper limit of conditional expression (1) is more preferably set to 1, further preferably 0.75, further preferably 0.65, further preferably 0.62, further preferably 0.59, and further preferably 0.56. For example, the imaging lens more preferably satisfies the following conditional expression (1-1).

[0111] 0.29 <f / f1<0.65(1-1)

[0112] In a structure where the first lens group G1 includes at least one positive lens, the imaging lens preferably satisfies the following condition (2). Here, the focal length of the positive lens with the strongest optical power among the positive lenses included in the first lens group G1 is set to fp1. By ensuring that the corresponding value of condition (2) is not below the lower limit, the optical system can be easily miniaturized. By ensuring that the corresponding value of condition (2) is not above the upper limit, spherical aberration can be easily corrected.

[0113] 0.1 <f / fp1<4(2)

[0114] To obtain better characteristics, the lower limit of condition (2) is more preferably set to 0.4, more preferably 0.6, more preferably 0.8, more preferably 0.9, more preferably 0.95, and more preferably 1. To obtain better characteristics, the upper limit of condition (2) is more preferably set to 2, more preferably 1.7, more preferably 1.4, more preferably 1.3, more preferably 1.27, and more preferably 1.25. For example, the imaging lens more preferably satisfies the following condition (2-1).

[0115] 0.9 <f / fp1<1.3(2-1)

[0116] In the structure where the first lens group G1 includes at least one positive lens and at least one negative lens, the imaging lens preferably satisfies the following condition (3). Here, the focal length of the positive lens closest to the object side among the positive lenses included in the first lens group G1 is set to fp1F. The focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group G1 is set to fn1. By ensuring that the corresponding value of condition (3) is not below the lower limit, spherical aberration can be easily corrected. By ensuring that the corresponding value of condition (3) is not above the upper limit, miniaturization of the optical system can be easily achieved.

[0117] 0.3 <fp1F / |fn1|<6 (3)

[0118] To obtain better characteristics, the lower limit of condition (3) is more preferably set to 0.8, more preferably 1.3, more preferably 1.9, more preferably 2.2, more preferably 2.3, more preferably 2.4, and more preferably 2.5. To obtain better characteristics, the upper limit of condition (3) is more preferably set to 5, more preferably 4.5, more preferably 4.1, more preferably 3.7, more preferably 3.4, more preferably 3.2, and more preferably 3. For example, the imaging lens more preferably satisfies the following condition (3-1).

[0119] 2.2 <fp1F / |fn1|<3.7 (3-1)

[0120] In the structure where the second lens group G2 includes at least one negative lens, the imaging lens preferably satisfies the following condition (4). Here, the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group G2 is set to fn2. By ensuring that the corresponding value of condition (4) is not below the lower limit, the miniaturization of the optical system can be easily achieved. By ensuring that the corresponding value of condition (4) is not above the upper limit, chromatic aberration due to magnification can be easily corrected.

[0121] 0.3 <f / |fn2|<6 (4)

[0122] To obtain better characteristics, the lower limit of condition (4) is more preferably set to 0.7, more preferably 1.05, more preferably 1.3, more preferably 1.55, more preferably 1.8, more preferably 2, and more preferably 2.2. To obtain better characteristics, the upper limit of condition (4) is more preferably set to 5, more preferably 4, more preferably 3.3, more preferably 3.1, more preferably 3, more preferably 2.9, and more preferably 2.8. For example, the imaging lens more preferably satisfies the following condition (4-1).

[0123] 1.55 <f / |fn2|<3.1 (4-1)

[0124] In the structure where the first lens group G1 includes at least one positive lens and at least one negative lens, the imaging lens preferably satisfies the following condition (5). By ensuring that the corresponding value of condition (5) is not below the lower limit, spherical aberration can be easily corrected. By ensuring that the corresponding value of condition (5) is not above the upper limit, miniaturization of the optical system can be easily achieved.

[0125] 0.15 <fp1 / |fn1|<6 (5)

[0126] To obtain better characteristics, the lower limit of condition (5) is more preferably set to 0.35, more preferably 0.75, more preferably 1, more preferably 1.3, more preferably 1.6, more preferably 1.7, and more preferably 1.75. To obtain better characteristics, the upper limit of condition (5) is more preferably set to 5, more preferably 4.5, more preferably 4, more preferably 3.5, more preferably 3.35, more preferably 3, and more preferably 2.6. For example, the imaging lens more preferably satisfies the following condition (5-1).

[0127] 1.6 <fp1 / |fn1|<3.5 (5-1)

[0128] In a structure where the first lens group G1 includes at least one positive lens, the imaging lens preferably satisfies the following condition (6). Here, the radius of curvature of the object-side surface of the positive lens with the strongest optical power among the positive lenses included in the first lens group G1 is set as Rf. The radius of curvature of the image-side surface of the positive lens with the strongest optical power among the positive lenses included in the first lens group G1 is set as Rr. By ensuring that the corresponding value of condition (6) is not below the lower limit, off-axis aberrations can be easily corrected. By ensuring that the corresponding value of condition (6) is not above the upper limit, the positive optical power of the positive lens with the strongest optical power among the positive lenses included in the first lens group G1 can be sufficiently enhanced, thus facilitating the miniaturization of the optical system.

[0129] 0.05 < (Rr + Rf) / (Rr - Rf) < 6 (6)

[0130] To obtain better characteristics, the lower limit of condition (6) is more preferably set to 0.2, more preferably 0.35, more preferably 0.5, more preferably 0.65, more preferably 0.8, more preferably 0.9, and more preferably 1. To obtain better characteristics, the upper limit of condition (6) is more preferably set to 4, more preferably 3, more preferably 2.5, more preferably 2.2, more preferably 2, more preferably 1.9, and more preferably 1.8. For example, the imaging lens more preferably satisfies the following condition (6-1).

[0131] 0.5 < (Rr + Rf) / (Rr - Rf) < 2.5 (6-1)

[0132] In the structure where the first lens group G1 includes at least one positive lens, 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 miniaturization of the optical system can be easily achieved. By ensuring that the corresponding value of condition (7) is not above the upper limit, spherical aberration can be easily corrected.

[0133] 0.3 <f1 / fp1<4.5 (7)

[0134] To obtain better properties, the lower limit of condition (7) is more preferably set to 0.5, more preferably 0.7, more preferably 0.8, more preferably 0.9, more preferably 1, more preferably 1.1, and more preferably 1.2. To obtain better properties, the upper limit of condition (7) is more preferably set to 3.8, more preferably 3.1, more preferably 2.8, more preferably 2.7, more preferably 2.6, more preferably 2.5, and more preferably 2.45.

[0135] In a structure in which the first lens group G1 includes at least one negative lens and the second lens group G2 includes at least one negative lens, the imaging lens preferably satisfies the following condition (8). By ensuring that the corresponding value of condition (8) is not below the lower limit, spherical aberration and image plane curvature can be easily corrected. By ensuring that the corresponding value of condition (8) is not above the upper limit, on-axis chromatic aberration can be easily corrected.

[0136] 0.1 <fn1 / fn2<6 (8)

[0137] To obtain better properties, the lower limit of condition (8) is more preferably set to 0.15, further preferably 0.2, further preferably 0.35, further preferably 0.4, further preferably 0.45, further preferably 0.5, and further preferably 0.55. To obtain better properties, the upper limit of condition (8) is more preferably set to 4, further preferably 2, further preferably 1.7, further preferably 1.5, further preferably 1.3, further preferably 1.1, and further preferably 1.

[0138] In a structure where the first lens group G1 includes at least one negative lens, the imaging lens preferably satisfies the following condition (9). By ensuring that the corresponding value of condition (9) is not below the lower limit, axial chromatic aberration can be easily corrected. By ensuring that the corresponding value of condition (9) is not above the upper limit, spherical aberration can be easily corrected.

[0139] 0.2 <f / |fn1|<5 (9)

[0140] To obtain better properties, the lower limit of condition (9) is more preferably set to 0.5, more preferably 0.8, more preferably 1.1, more preferably 1.4, more preferably 1.7, more preferably 1.9, and more preferably 2.1. To obtain better properties, the upper limit of condition (9) is more preferably set to 4, more preferably 3.7, more preferably 3.5, more preferably 3.3, more preferably 3.2, more preferably 3.1, and more preferably 3.

[0141] In a structure where the first lens group G1 includes at least one positive lens, the imaging lens preferably satisfies the following condition (10). Here, the refractive index of the positive lens closest to the object side among the positive lenses included in the first lens group G1 relative to the d-line is set to NplF. By ensuring that the corresponding value of condition (10) is not below the lower limit, it is beneficial to miniaturize the optical system. By ensuring that the corresponding value of condition (10) is not above the upper limit, it is possible to suppress the weight increase of the lens.

[0142] 1.5 <Np1F<2.03 (10)

[0143] To obtain better properties, the lower limit of condition (10) is more preferably set to 1.6, more preferably 1.7, more preferably 1.74, and more preferably 1.78. To obtain better properties, the upper limit of condition (10) is more preferably set to 1.98, more preferably 1.94, more preferably 1.92, and more preferably 1.9.

[0144] When the focal length of the second lens group G2 is set to f2 when focusing on an object at infinity, the imaging lens preferably satisfies the following condition (14). By ensuring that the corresponding value of condition (14) is not below the lower limit, the positive optical power of the second lens group G2 can be ensured, which is beneficial for shortening the overall length of the lens. By ensuring that the corresponding value of condition (14) is not above the upper limit, the positive optical power of the second lens group G2 will not become too strong, which makes it easier to suppress spherical aberration and / or astigmatism.

[0145] 0.4 <f / f2<2.5 (14)

[0146] To obtain better properties, the lower limit of condition (14) is more preferably set to 0.6, more preferably 0.75, and more preferably 0.9. To obtain better properties, the upper limit of condition (14) is more preferably set to 2, more preferably 1.6, and more preferably 1.2.

[0147] When the radius of curvature of the lens surface closest to the object in the second lens group G2 is set to R21f, the imaging lens preferably satisfies the following condition (16). By ensuring that the corresponding value of condition (16) is not below the lower limit, overcorrection of spherical aberration can be prevented. By ensuring that the corresponding value of condition (16) is not above the upper limit, undercorrection of spherical aberration can be prevented.

[0148] -2 <R21f / f2<-0.1 (16)

[0149] To obtain better characteristics, the lower limit of condition (16) is more preferably set to -1.6, further preferably -1.2, and even more preferably -0.8. To obtain better characteristics, the upper limit of condition (16) is more preferably set to -0.2, further preferably -0.25, and even more preferably -0.3.

[0150] When the back focal length of the imaging lens at the air-converted distance is set to Bf, the imaging lens preferably satisfies the following condition (17). The back focal length at the air-converted distance is the air-converted distance along the optical axis from the lens surface closest to the image side to the image plane Sim. By ensuring that the corresponding value of condition (17) is not below the lower limit, the back focal length required for interchangeable lenses of the camera can be easily ensured. By ensuring that the corresponding value of condition (17) is not above the upper limit, the increase in the total length of the lens can be suppressed.

[0151] 0.05 <Bf / f<0.7 (17)

[0152] To obtain better properties, the lower limit of condition (17) is more preferably set to 0.1, more preferably 0.15, and more preferably 0.2. To obtain better properties, the upper limit of condition (17) is more preferably set to 0.6, more preferably 0.5, and more preferably 0.45.

[0153] The imaging lens preferably satisfies the following condition (18). Here, the Abbe number of the d-line reference of the positive lens with the strongest optical power among the positive lenses included in the first lens group G1 is set to νp1. By ensuring that the corresponding value of condition (18) is not below the lower limit, axial chromatic aberration can be easily corrected. By ensuring that the corresponding value of condition (18) is not above the upper limit, the refractive index of the positive lens with the strongest optical power among the positive lenses included in the first lens group G1 will not become too low, thus easily ensuring the positive optical power of this positive lens.

[0154] 38 <vp1<96 (18)

[0155] To obtain better properties, the lower limit of condition (18) is more preferably set to 48, further preferably 58, further preferably 64, and further preferably 70. To obtain better properties, the upper limit of condition (18) is more preferably set to 90, further preferably 86, further preferably 84, and further preferably 82.

[0156] In a structure where the imaging lens includes a first aspherical lens, at least one first aspherical lens preferably satisfies the following condition (20). Here, the radius of curvature at the position of the maximum effective diameter of the object-side surface of the first aspherical lens is set as Raly. The paraxial radius of curvature of the object-side surface of the first aspherical lens is set as Ra1c. By ensuring that the corresponding value of condition (20) is not below the lower limit, the negative optical power of the peripheral portion of the lens will not become too weak, thus making it easy to correct off-axis aberrations. By ensuring that the corresponding value of condition (20) is not above the upper limit, the positive optical power in the paraxial region will not become too weak, thus making it easy to correct spherical aberrations.

[0157] -10 <Ra1y / Ralc<0(20)

[0158] To obtain better properties, the lower limit of condition (20) is more preferably set to -5, further preferably -3, further preferably -1, and further preferably -0.8. To obtain better properties, the upper limit of condition (20) is more preferably set to -0.05, further preferably -0.1, further preferably -0.15, and further preferably -0.2.

[0159] Here, for reference Figure 4 The location of the maximum effective diameter in this specification will be explained. Figure 4This is an illustrative diagram showing the structure within a cross-section including the optical axis Z. Figure 4 In the image, the left side is the object side, and the right side is the image side. Figure 4 The image shows the on-axis beam Xa and off-axis beam Xb passing through lens Lx. Figure 4 In the example, the upper ray of the off-axis beam Xb, i.e., ray Xbl, is the ray that passes through the outermost edge. Here, "outer edge" refers to the radially outer edge centered on the optical axis Z, i.e., the side furthest from the optical axis Z. In this specification, the position of the intersection of this outermost ray and the lens surface is the position Px of the maximum effective diameter. Furthermore, twice the distance from the position Px of the maximum effective diameter to the optical axis Z is the effective diameter ED of the object-side surface of the lens Lx. Additionally, in... Figure 4 In the example, the upper ray of the off-axis beam Xb is the ray that passes through the outermost edge, but which ray becomes the ray that passes through the outermost edge varies depending on the optical system.

[0160] In a structure where the imaging lens includes a second aspherical lens, at least one second aspherical lens preferably satisfies the following condition (21). Here, the radius of curvature at the position of the maximum effective diameter of the object-side surface of the second aspherical lens is set as Ra2y. The paraxial radius of curvature of the object-side surface of the second aspherical lens is set as Ra2c. By ensuring that the corresponding value of condition (21) is not below the lower limit, the positive optical power of the peripheral portion of the lens will not become too weak, thus facilitating a reduction in the incident angle of the off-axis principal ray towards the image plane Sim. By ensuring that the corresponding value of condition (21) is not above the upper limit, the negative optical power in the paraxial region will not become too weak, thus easily preventing overcorrection of spherical aberration.

[0161] -10 <Ra2y / Ra2c<0(21)

[0162] To obtain better properties, the lower limit of condition (21) is more preferably set to -5, further preferably -3, further preferably -1, and further preferably -0.8. To obtain better properties, the upper limit of condition (21) is more preferably set to -0.05, further preferably -0.1, further preferably -0.15, and further preferably -0.2.

[0163] In a structure where the imaging lens includes a third aspherical lens, at least one third aspherical lens preferably satisfies the following condition (22). Here, the radius of curvature at the position of the maximum effective diameter of the image-side surface of the third aspherical lens is set as Ra3y. The paraxial radius of curvature of the image-side surface of the third aspherical lens is set as Ra3c. By ensuring that the corresponding value of condition (22) is not below the lower limit, the negative optical power of the peripheral portion of the lens will not become too weak, thus making it easy to correct off-axis aberrations. By ensuring that the corresponding value of condition (22) is not above the upper limit, the positive optical power in the paraxial region will not become too weak, thus making it easy to correct spherical aberrations.

[0164] -10 <Ra3y / Ra3c<0(22)

[0165] To obtain better properties, the lower limit of condition (22) is more preferably set to -5, further preferably -3, further preferably -1, and further preferably -0.8. To obtain better properties, the upper limit of condition (22) is more preferably set to -0.05, further preferably -0.1, further preferably -0.15, and further preferably -0.2.

[0166] In a structure where the imaging lens includes a fourth aspherical lens, at least one fourth aspherical lens preferably satisfies the following condition (23). Here, the radius of curvature at the position of the maximum effective diameter of the image-side surface of the fourth aspherical lens is set as Ra4y. The paraxial radius of curvature of the image-side surface of the fourth aspherical lens is set as Ra4c. By ensuring that the corresponding value of condition (23) is not below the lower limit, the positive optical power of the peripheral portion of the lens will not become too weak, thus facilitating a reduction in the incident angle of the off-axis principal ray towards the image plane Sim. By ensuring that the corresponding value of condition (23) is not above the upper limit, the negative optical power in the paraxial region will not become too weak, thus easily preventing overcorrection of spherical aberration.

[0167] -10 <Ra4y / Ra4c<0(23)

[0168] To obtain better properties, the lower limit of condition (23) is more preferably set to -5, further preferably -3, further preferably -1, and further preferably -0.6. To obtain better properties, the upper limit of condition (23) is more preferably set to -0.05, further preferably -0.1, further preferably -0.15, and further preferably -0.2.

[0169] in addition, Figure 1 The example shown is one illustration; the imaging lens of the present invention can be modified in various ways without departing from the technical spirit of the invention. For example, the number of lenses included in each lens group can be [number missing]. Figure 1 The number of examples varies.

[0170] In the imaging lens of the present invention, as described later in Embodiment 3 (see reference) Figure 8 As shown in the figures, the second lens group G2 can be configured to include a front portion group G2F and a rear portion group G2R sequentially from the object side to the image side. Furthermore, it can be configured such that, during focusing, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally along the optical axis Z, while the rear portion group G2R is fixed relative to the image plane Sim. Setting the rear portion group G2R fixed during focusing simplifies the mechanism. The rear portion group G2R can be a group with positive optical power or a group with negative optical power.

[0171] The rear section group G2R preferably includes one or more lenses, each including at least one lens surface with a pole. With this configuration, aberrations associated with focusing are easily suppressed. To further improve this effect, the rear section group G2R more preferably includes two or more lenses, each including at least one lens surface with a pole.

[0172] The second lens group G2, from the object side to the image side, includes a front portion group G2F and a rear portion group G2R. The rear portion group G2R includes one or more lenses, each including at least one lens surface with a pole. During focusing, the rear portion group G2R is fixed relative to the image surface Sim, while the other groups and the aperture stop St move together. In this structure, the imaging lens preferably satisfies the following condition (11). Here, the sum of the air gaps on the optical axis within the rear portion group G2R is defined as D2Rair. The distance on the optical axis from the lens surface closest to the object side of the rear portion group G2R to the lens surface closest to the image side of the rear portion group G2R is defined as D2R. By satisfying condition (11), it is beneficial to suppress various aberrations.

[0173] 0≤D2Rair / D2R<0.45 (11)

[0174] To obtain better properties, the lower limit of condition (11) is more preferably set to 0.01, more preferably 0.015, more preferably 0.02, and more preferably 0.025. To obtain better properties, the upper limit of condition (11) is more preferably set to 0.4, more preferably 0.36, more preferably 0.32, and more preferably 0.29.

[0175] The second lens group G2 includes a front portion group G2F and a rear portion group G2R sequentially from the object side to the image side. The rear portion group G2R includes one or more lenses, each including at least one lens surface with a pole. During focusing, the rear portion group G2R is fixed relative to the image surface Sim, while the other groups and the aperture stop St move together. In this structure, the imaging lens preferably satisfies the following condition (12). Here, the distance on the optical axis from the lens surface closest to the object side of the first lens group G1 to the lens surface closest to the image side of the rear portion group G2R when focusing on an object at infinity is set to DT. By ensuring that the corresponding value of condition (12) is not below the lower limit, it is easy to achieve a significant reduction in the size of the optical system while ensuring the optical path length used to correct various aberrations within the rear portion group G2R. By ensuring that the corresponding value of condition (12) is not above the upper limit, the thickness of the rear portion group G2R in the optical axis direction will not become too large, thus facilitating a reduction in the overall optical length.

[0176] 0.05 <D2R / DT<0.5(12)

[0177] To obtain better characteristics, the lower limit of condition (12) is more preferably set to 0.12, more preferably 0.18, and even more preferably 0.22. To obtain better characteristics, the upper limit of condition (12) is more preferably set to 0.45, more preferably 0.4, and even more preferably 0.36. For example, the imaging lens more preferably satisfies the following condition (12-1).

[0178] 0.22 <D2R / DT<0.36(12-1)

[0179] The second lens group G2 comprises a front portion group G2F and a rear portion group G2R sequentially from the object side to the image side. During focusing, the rear portion group G2R is fixed relative to the image plane Sim, while the other groups and the aperture stop St move together. In this structure, the rear portion group G2R preferably includes at least one lens that satisfies the following condition (13). Here, the refractive index of the lens included in the rear portion group G2R relative to the d-line is set to N2R. The Abbe number of the lens included in the rear portion group G2R based on the d-line is set to ν2R. By ensuring that the corresponding value of condition (13) is not below the lower limit, materials other than those with low refractive index and low Abbe number can be selected, thus making it easy to correct chromatic aberration. By ensuring that the corresponding value of condition (13) is not above the upper limit, materials other than those with high refractive index and high Abbe number can be selected, thus making it easy to select materials with low specific gravity and achieve lightweight design.

[0180] 1.8 <N2R+0.01×ν2R<2.14 (13)

[0181] To obtain better properties, the lower limit of condition (13) is more preferably set to 1.85, more preferably 1.9, and even more preferably 1.95. To obtain better properties, the upper limit of condition (13) is more preferably set to 2.13, more preferably 2.12, and even more preferably 2.11.

[0182] The second lens group G2 consists of a front portion group G2F and a rear portion group G2R, arranged sequentially from the object side to the image side. During focusing, the rear portion group G2R is fixed relative to the image plane Sim, while the other groups and the aperture stop St move together. In this structure, the imaging lens preferably satisfies the following condition (15). Here, the focal length of the rear portion group G2R is set to f2R. By satisfying condition (15), the absolute value of the Pezvar sum can be made close to zero, thus preventing an increase in image plane curvature. Furthermore, by satisfying condition (15), variations in various aberrations can be suppressed when focusing from an object at infinity to a closer object.

[0183] 0.05 < |f / f²R| < 1.5 (15)

[0184] To obtain better properties, the lower limit of condition (15) is more preferably set to 0.15, more preferably 0.25, and more preferably 0.3. To obtain better properties, the upper limit of condition (15) is more preferably set to 1.2, more preferably 0.9, and more preferably 0.75.

[0185] As described in Example 10 below (see reference) Figure 22 As shown in the figures, the imaging lens of the present invention may include a three-piece combined lens consisting of a first positive lens, a second positive lens, and a negative lens joined sequentially. This three-piece combined lens can be joined sequentially from the object side to the image side, or sequentially from the image side to the object side. This three-piece combined lens is advantageous for suppressing chromatic aberration.

[0186] In a structure comprising a three-element composite lens consisting of a first positive lens, a second positive lens, and a negative lens joined sequentially, the imaging lens preferably satisfies the following conditional expression (19). Here, the Abbe number of the d-line reference of the first positive lens of the three-element composite lens is set as vcp1. The Abbe number of the d-line reference of the second positive lens of the three-element composite lens is set as vcp2. By ensuring that the corresponding value of conditional expression (19) is not below the lower limit, chromatic aberration can be easily corrected. By ensuring that the corresponding value of conditional expression (19) is not above the upper limit, the refractive index of the first positive lens will not become too low, thus facilitating the correction of spherical aberration.

[0187] 16<ν cp1-ν cp2<83 (19)

[0188] To obtain better properties, the lower limit of condition (19) is more preferably set to 17.5, and even more preferably to 18.5. To obtain better properties, the upper limit of condition (19) is more preferably set to 78, and even more preferably to 75.

[0189] The above-mentioned preferred structures and achievable structures can be arbitrarily combined within a non-contradictory range, and preferably selected appropriately according to the required specifications.

[0190] As an example, a preferred embodiment of the imaging lens of the present invention is an imaging lens comprising a first lens group G1, an aperture stop St, and a second lens group G2 in sequence from the object side to the image side. During focusing, the imaging lens moves as a whole, or a portion of the first lens group G1, the aperture stop St, and the second lens group G2 moves, and satisfies the above conditional expression (1).

[0191] Next, embodiments of the imaging lens of the present invention will be described with reference to the accompanying drawings. Furthermore, the reference numerals labeled in the cross-sectional views and on the lens of each embodiment are used independently for each embodiment to avoid complexity in the description and drawings caused by an increase in the number of reference numerals. Therefore, even if common reference numerals are used in the drawings of different embodiments, they do not necessarily represent a common structure.

[0192] [Example 1]

[0193] exist Figure 1 The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 1. The illustration method and structure are as described above, and therefore some repetitive descriptions are omitted here. The imaging lens of Embodiment 1, from the object side to the image side, sequentially includes a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical power. When focusing from an object at infinity to a closer object, the imaging lens as a whole moves integrally towards the object side along the optical axis Z.

[0194] Regarding the imaging lens of Example 1, the basic lens data is shown in Table 1, the specifications and variable surface spacing are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0195] The basic lens data sheet is as follows. The "Sn" column shows the surface numbering with the object-side surface designated as surface 1 and the numbering increasing sequentially towards the image side. The "R" column shows the radius of curvature of each surface. The "D" column shows the surface spacing along the optical axis of each surface and its image-side neighbor. The "Nd" column shows the refractive index of each lens relative to the d-line. The "νd" column shows the Abbe number of each lens based on the d-line reference.

[0196] The "Material" column in the basic lens data table is listed as follows. In this column, lenses made of resin are listed as "Plastic." Lenses made of materials other than resin are indicated by a period between the material name and the name of the manufacturing company. The manufacturing company names are briefly shown in the table below: "CDGM" represents Chengdu Guangming Optoelectronics Co., Ltd.; "OHARA" represents OHARA INC.; and "HOYA" represents HOYA Corporation.

[0197] The effective diameter of each surface is shown in the "ED" column. Furthermore, on the left side of the "Sn" column, the rows corresponding to the lenses of the 1st, 2nd, 3rd, and 4th aspherical lenses are labeled "La1", "La2", "La3", and "La4", respectively.

[0198] In the table of basic lens data, the radius of curvature of the surface that makes the convex shape face the object side is marked with a positive sign, and the radius of curvature of the surface that makes the convex shape face the image side is marked with a negative sign. The surface number and the term (St) are recorded in the column corresponding to the aperture stop St. The bottom column of column D in the table shows the interval between the image-side surface and the image plane Sim. Regarding the variable surface interval during focusing, the notation DD[] is used, with the object-side surface number of that interval marked in [] and recorded in the surface interval column.

[0199] Table 2 shows the focal length, back focal length, open F-number, maximum angle of view, and variable plane spacing of the imaging lens, using the d-line as a reference. The [°] in the maximum angle of view column indicates the unit as degrees. Table 2 shows the values ​​for focusing on an object at infinity in the "Infinity" column and the values ​​for focusing on a nearby object in the "Close" column. The focal length is only shown for focusing on an object at infinity. In the "Close" column, the absolute value of the magnification for focusing on a nearby object is indicated by "times".

[0200] In the basic lens data, aspherical surfaces are marked with an asterisk (*), and the paraxial radius of curvature is recorded in the aspherical surface radius of curvature column. Table 3 shows the aspherical surface number in row Sn, and the aspherical coefficient values ​​for each aspherical surface in rows KA and Am. Furthermore, m in Am is an integer greater than or equal to 3, and varies depending on the surface. For example, in the 10th surface of Example 1, m = 4, 6, 8, 10, 12, 14, 16, 18. The "E±n" (n: integer) value for the aspherical coefficient values ​​in Table 3 represents "×10". ±n KA and Am are the aspheric coefficients in the aspheric formula expressed by the following equation.

[0201] Zd=C×h2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+∑Am×h m

[0202] Where Zd: Aspheric depth (the length of the perpendicular line from a point on the aspheric surface at height h to a plane tangent to the vertex of the aspheric surface and perpendicular to the optical axis Z).

[0203] h: Height (distance from the optical axis Z to the lens surface)

[0204] C: The reciprocal of the paraxial radius of curvature

[0205] KA, Am: Aspheric coefficients

[0206] In aspherical form, ∑ represents the sum related to m.

[0207] In the data in each table, degrees are used as the unit of angle, and millimeters (mm) are used as the unit of length. The optical system can use both magnification and reduction scales, so other appropriate units can also be used. Furthermore, the values ​​rounded to a preset number of decimal places are recorded in the tables shown below.

[0208] [Table 1]

[0209] Example 1

[0210]

[0211] [Table 2]

[0212] Example 1

[0213]

[0214] [Table 3]

[0215] Example 1

[0216]

[0217] Figure 5 The diagram shows the aberrations of the imaging lens in Example 1. Figure 5 In the middle, from left to right, are shown spherical aberration, astigmatism, distortion aberration, and magnification chromatic aberration. Figure 5In the diagram, the upper section labeled "Infinity" shows the aberration diagrams for focusing on an object at infinity, and the lower section labeled "Near Distance" shows the aberration diagrams for focusing on a near object. In the spherical aberration diagram, the aberrations of the d-line, C-line, and F-line are shown using solid lines, long dashed lines, and short dashed lines, respectively. In the astigmatism diagram, the aberration of the d-line in the sagittal direction is shown using solid lines, and the aberration of the d-line in the meridional direction is shown using short dashed lines. In the distortion aberration diagram, the aberration of the d-line is shown using solid lines. In the chromatic aberration diagram, the aberrations of the C-line and F-line are shown using long dashed lines and short dashed lines, respectively. In the spherical aberration diagram, the open F-value is shown after "FNo.=". In other aberration diagrams, the maximum half-angle value is shown after "ω=".

[0218] The notations, meanings, recording methods, and illustration methods of the data related to Embodiment 1 above are basically the same in the following embodiments unless otherwise specified, so repeated descriptions are omitted below.

[0219] [Example 2]

[0220] Figure 6 The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 2. The imaging lens of Embodiment 2, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 four lenses, L21 to L24, from the object side to the image side. When focusing from an object at infinity to a closer object, the entire imaging lens moves integrally towards the object side along the optical axis Z.

[0221] 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 7 .

[0222] [Table 4]

[0223] Example 2

[0224]

[0225] [Table 5]

[0226] Example 2

[0227]

[0228] [Table 6]

[0229] Example 2

[0230] Sn 11 12 13 14 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A4 3.5192725E-06 2.6928550E-05 9.3429706E-05 8.7894932E-05 A6 2.2642027E-08 1.0946193E-07 -8.9106463E-08 -1.7572633E-07 A8 2.7059542E-10 3.4621068E-10 5.2090671E-10 5.1163778E-10 A10 1.0340795E-12 -1.8786076E-13 4.4026398E-14 1.0297447E-12 A12 -2.2807761E-15 6.5775949E-15 -5.7047490E-15 -8.5962546E-15

[0231] [Example 3]

[0232] Figure 8 The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 3. The imaging lens of Embodiment 3, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R consists of one lens, L25. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0233] 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 9 .

[0234] [Table 7]

[0235] Example 3

[0236]

[0237] [Table 8]

[0238] Example 3

[0239]

[0240] [Table 9]

[0241] Example 3

[0242]

[0243] [Example 4]

[0244] Figure 10The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 4. The imaging lens of Embodiment 4, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R consists of one lens, L25. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0245] 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 11 .

[0246] [Table 10] Example 4

[0247]

[0248] [Table 11]

[0249] Example 4

[0250]

[0251] [Table 12]

[0252] Example 4

[0253]

[0254] [Example 5]

[0255] Figure 12 The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 5. The imaging lens of Embodiment 5, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R consists of one lens, L25. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0256] 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 13 .

[0257] [Table 13]

[0258] Example 5

[0259]

[0260] [Table 14]

[0261] Example 5

[0262]

[0263] [Table 15]

[0264] Example 5

[0265]

[0266] [Example 6]

[0267] Figure 14 The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 6. The imaging lens of Embodiment 6, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises two lenses, L25 to L26, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0268] 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 15 .

[0269] [Table 16]

[0270] Example 6

[0271]

[0272] [Table 17]

[0273] Example 6

[0274]

[0275] [Table 18]

[0276] Example 6

[0277] Sn 14 15 16 17 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A4 -2.8253644E-05 5.6216746E-05 1.2434340E-04 2.4921498E-05 A6 -8.6165184E-09 3.0961641E-07 3.3284430E-07 -1.5563145E-07 A8 -1.0573101E-09 -2.5233117E-09 -1.9851876E-09 1.5723376E-09 A10 1.5308446E-11 1.0021559E-11 6.0254705E-13 -8.0174739E-12 A12 -5.0994669E-14 -7.9588567E-15 1.6392441E-14 2.0716244E-14 A14 -1.0634277E-16 -5.6305233E-17 8.1527567E-18 -8.2647243E-18 A16 9.8954758E-19 1.5788102E-19 -2.2444765E-19 -7.0554552E-20 A18 -1.6752916E-21 -6.5635025E-23 3.9040994E-22 1.0089161E-22

[0278] [Example 7]

[0279] Figure 16 The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 7. The imaging lens of Embodiment 7, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises two lenses, L25 to L26, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0280] 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 17 .

[0281] [Table 19]

[0282] Example 7

[0283]

[0284] [Table 20]

[0285] Example 7

[0286]

[0287] [Table 21]

[0288] Example 7

[0289] Sn 13 14 15 16 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A4 -2.6835506E-05 6.7995710E-05 1.3702655E-04 2.3059681E-05 A6 -1.4419760E-08 3.0422367E-07 3.4468525E-07 -1.5255884E-07 A8 -1.3175644E-09 -2.6440179E-09 -1.9536639E-09 1.6421350E-09 A10 1.5012424E-11 9.9001164E-12 6.5592162E-13 -7.8247116E-12 A12 -2.9361824E-15 -4.0173796E-15 1.4895066E-14 2.0105144E-14 A14 -3.9149114E-16 4.2585344E-17 -2.7077425E-17 -2.1017559E-17 A16 1.2608941E-18 -7.2163925E-19 6.1180123E-21 -3.1324492E-20 A18 -1.0402942E-21 1.6833075E-21 -4.3333127E-23 3.9443728E-23

[0290] [Example 8]

[0291] Figure 18The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 8. The imaging lens of Embodiment 8, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises three lenses, L21 to L23, from the object side to the image side. The rear portion group G2R comprises two lenses, L24 to L25, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0292] Regarding the imaging lens of Example 8, the basic lens data is shown in Table 22, the specifications and variable surface spacing are shown in Table 23, the aspherical coefficients are shown in Table 24, and the various aberrations are illustrated in Table 25. Figure 19 .

[0293] [Table 22]

[0294] Example 8

[0295]

[0296] [Table 23]

[0297] Example 8

[0298]

[0299] [Table 24]

[0300] Example 8

[0301] Sn 12 13 14 15 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A4 -1.7862292E-05 1.2570630E-04 1.7040648E-04 -3.1215346E-05 A6 2.3668946E-07 1.0218487E-07 2.4052271E-07 1.7196317E-07 A8 -2.2704951E-09 -1.3092084E-09 -3.8306731E-09 -3.5481652E-11 A10 1.9886943E-11 2.1327048E-12 7.7776485E-12 -7.4385832E-12 A12 -5.6906836E-14 1.4265676E-14 4.1560550E-14 4.2992450E-14 A14 -5.3587649E-16 9.7539059E-17 -1.5595827E-16 -8.6127541E-17 A16 4.7736159E-18 -1.0074751E-18 -1.2407286E-19 -7.1994147E-20 A18 -1.0979001E-20 2.5564056E-21 1.1005447E-21 4.1683287E-22

[0302] [Example 9]

[0303] Figure 20The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 9. The imaging lens of Embodiment 9, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises three lenses, L21 to L23, from the object side to the image side. The rear portion group G2R comprises two lenses, L24 to L25, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0304] Regarding the imaging lens of Example 9, the basic lens data is shown in Table 25, the specifications and variable surface spacing are shown in Table 26, the aspherical coefficients are shown in Table 27, and the various aberrations are illustrated in Table 28. Figure 21 .

[0305] [Table 25]

[0306] Example 9

[0307]

[0308] [Table 26]

[0309] Example 9

[0310]

[0311] [Table 27]

[0312] Example 9

[0313]

[0314] [Example 10]

[0315] Figure 22The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 10. The imaging lens of Embodiment 10, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises five lenses, L21 to L25, from the object side to the image side. The rear portion group G2R comprises two lenses, L26 to L27, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0316] Regarding the imaging lens of Example 10, the basic lens data is shown in Table 28, the specifications and variable surface spacing are shown in Table 29, the aspherical coefficients are shown in Table 30, and the various aberrations are illustrated in Table 30. Figure 23 .

[0317] [Table 28]

[0318] Example 10

[0319]

[0320] [Table 29]

[0321] Example 10

[0322]

[0323] [Table 30]

[0324] Example 10

[0325] Sn 14 15 16 17 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A4 -1.8898160E-05 6.6948595E-05 7.1703356E-05 -3.2607326E-05 A6 2.5832024E-07 6.0982421E-07 8.3680986E-07 1.2810581E-07 A8 -3.3171118E-09 -2.6889785E-09 -2.4141994E-09 5.7017102E-10 A10 1.9896151E-11 6.7958769E-12 2.0624405E-12 -9.3661245E-12 A12 6.7011942E-15 1.1410780E-14 5.9663417E-15 3.7855070E-14 A14 -4.0083385E-16 6.3710009E-17 -6.8762976E-17 -8.3411974E-18 A16 9.5294214E-19 -1.2059108E-18 2.7125346E-19 -2.4204936E-19 A18 -2.0020798E-22 2.8123567E-21 -1.9917493E-22 3.0602016E-22

[0326] [Example 11]

[0327] Figure 24The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 11. The imaging lens of Embodiment 11, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises three lenses, L25 to L27, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0328] Regarding the imaging lens of Example 11, the basic lens data is shown in Table 31, the specifications and variable surface spacing are shown in Table 32, the aspherical coefficients are shown in Table 33, and the various aberrations are illustrated in Table 34. Figure 25 .

[0329] [Table 31]

[0330] Example 11

[0331]

[0332] [Table 32]

[0333] Example 11

[0334]

[0335] [Table 33]

[0336] Example 11

[0337]

[0338] [Example 12]

[0339] Figure 26The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 12. The imaging lens of Embodiment 12, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical power. The first lens group G1 comprises four lenses, L11 to L14, from the object side to the image side. The second lens group G2 comprises a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises three lenses, L25 to L27, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0340] Regarding the imaging lens of Example 12, the basic lens data is shown in Table 34, the specifications and variable surface spacing are shown in Table 35, the aspherical coefficients are shown in Table 36, and the various aberrations are illustrated in Table 37. Figure 27 .

[0341] [Table 34]

[0342] Example 12

[0343]

[0344] [Table 35]

[0345] Example 12

[0346]

[0347] [Table 36]

[0348] Example 12

[0349]

[0350] [Example 13]

[0351] Figure 28The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 13. The imaging lens of Embodiment 13, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises three lenses, L25 to L27, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0352] Regarding the imaging lens of Example 13, the basic lens data is shown in Table 37, the specifications and variable surface spacing are shown in Table 38, the aspherical coefficients are shown in Table 39, and the various aberrations are illustrated in Table 30. Figure 29 .

[0353] [Table 37] Example 13

[0354]

[0355] [Table 38]

[0356] Example 13

[0357]

[0358] [Table 39]

[0359] Example 13

[0360]

[0361] [Example 14]

[0362] Figure 30The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 14. The imaging lens of Embodiment 14, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical power. The first lens group G1 comprises four lenses, L11 to L14, from the object side to the image side. The second lens group G2 comprises a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises three lenses, L21 to L23, from the object side to the image side. The rear portion group G2R comprises three lenses, L24 to L26, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0363] Regarding the imaging lens of Example 14, the basic lens data is shown in Table 40, the specifications and variable surface spacing are shown in Table 41, the aspherical coefficients are shown in Table 42, and the various aberrations are illustrated in Table 43. Figure 31 .

[0364] [Table 40]

[0365] Example 14

[0366]

[0367] [Table 41]

[0368] Example 14

[0369]

[0370] [Table 42]

[0371] Example 14

[0372]

[0373] [Example 15]

[0374] Figure 32The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 15. The imaging lens of Embodiment 15, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical 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 a front portion group G2F and a rear portion group G2R from the object side to the image side. The front portion group G2F comprises three lenses, L21 to L23, from the object side to the image side. The rear portion group G2R comprises three lenses, L24 to L26, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0375] Regarding the imaging lens of Example 15, the basic lens data is shown in Table 43, the specifications and variable surface spacing are shown in Table 44, the aspherical coefficients are shown in Table 45, and the various aberrations are illustrated in Table 46. Figure 33 .

[0376] [Table 43]

[0377] Example 15

[0378]

[0379] [Table 44]

[0380] Example 15

[0381]

[0382] [Table 45]

[0383] Example 15

[0384]

[0385] [Example 16]

[0386] Figure 34The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 16. The imaging lens of Embodiment 16, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical power. The first lens group G1 comprises four lenses, L11 to L14, from the object side to the image side. The second lens group G2 comprises a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises three lenses, L21 to L23, from the object side to the image side. The rear portion group G2R comprises three lenses, L24 to L26, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0387] Regarding the imaging lens of Example 16, the basic lens data is shown in Table 46, the specifications and variable surface spacing are shown in Table 47, the aspherical coefficients are shown in Table 48, and the various aberrations are illustrated in Table 49. Figure 35 .

[0388] [Table 46] Example 16

[0389]

[0390] [Table 47]

[0391] Example 16

[0392]

[0393] [Table 48]

[0394] Example 16

[0395]

[0396] [Example 17]

[0397] Figure 36The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 17. The imaging lens of Embodiment 17, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical power. The first lens group G1 comprises four lenses, L11 to L14, from the object side to the image side. The second lens group G2 comprises a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises four lenses, L25 to L28, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0398] Regarding the imaging lens of Example 17, the basic lens data is shown in Table 49, the specifications and variable surface spacing are shown in Table 50, the aspherical coefficients are shown in Table 51, and the various aberrations are illustrated in Table 52. Figure 37 .

[0399] [Table 49] Example 17

[0400]

[0401] [Table 50]

[0402] Example 17

[0403]

[0404] [Table 51]

[0405] Example 17

[0406]

[0407] [Example 18]

[0408] Figure 38The diagram shows a cross-sectional view of the imaging lens structure of Embodiment 18. The imaging lens of Embodiment 18, from the object side to the image side, comprises a first lens group G1 with positive optical power, an aperture stop St, and a second lens group G2 with positive optical power. The first lens group G1 comprises four lenses, L11 to L14, from the object side to the image side. The second lens group G2 comprises a front portion group G2F and a rear portion group G2R, from the object side to the image side. The front portion group G2F comprises four lenses, L21 to L24, from the object side to the image side. The rear portion group G2R comprises four lenses, L25 to L28, from the object side to the image side. When focusing from an object at infinity to a closer object, the first lens group G1, the aperture stop St, and the front portion group G2F move integrally towards the object side along the optical axis Z, while the rear portion group G2R remains fixed relative to the image plane Sim.

[0409] Regarding the imaging lens of Example 18, the basic lens data is shown in Table 52, the specifications and variable surface spacing are shown in Table 53, the aspherical coefficients are shown in Table 54, and the various aberrations are illustrated in Table 55. Figure 39 .

[0410] [Table 52] Example 18

[0411]

[0412] [Table 53]

[0413] Example 18

[0414]

[0415] [Table 54]

[0416] Example 18

[0417]

[0418] Tables 55 to 58 show the corresponding values ​​of conditional expressions (1) to (23) for the imaging lenses of Examples 1 to 18. The corresponding values ​​of the examples shown in Tables 55 to 58 can be used as upper or lower limits of the conditional expressions to set the preferred range of the conditional expressions.

[0419] [Table 55]

[0420]

[0421] [Table 56]

[0422]

[0423] [Table 57]

[0424]

[0425] [Table 58]

[0426]

[0427] The imaging lenses of Examples 1 to 18 all have small F-numbers. Specifically, the F-number when focused on an object at infinity is less than 1.5 in all imaging lenses of Examples 1 to 18, and less than 1.3 in some of the imaging lenses of Examples 1 to 16. Furthermore, the imaging lenses of Examples 1 to 16 are all configured to be small, and all aberrations are well corrected while maintaining high optical performance.

[0428] Next, the imaging device according to the embodiments of the present invention will be described. Figure 40 and Figure 41 The diagram shows the external appearance of the camera 30 of the imaging device according to one embodiment of the present invention. Figure 40 This is a stereoscopic view of camera 30 viewed from the front side. Figure 41 This 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 allows for the detachable mounting of 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.

[0429] The camera 30 includes a camera body 31. 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 in the field of view before shooting.

[0430] A photographic opening for light from the photographed object is provided at the center of the front surface of the camera body 31. A bayonet 37 is provided at a position corresponding to the photographic opening, through which the interchangeable lens 20 is mounted on the camera body 31.

[0431] An imaging element 38 is provided within the camera body 31. The imaging element 38 outputs an imaging signal corresponding to the image of the subject formed by the interchangeable lens 20. The imaging element 38 can be, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). A signal processing circuit (not shown) and a recording medium (not shown) are provided within the camera body 31. The signal processing circuit processes the imaging signal output from the imaging element 38 to generate an image. The recording medium is used to record 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.

[0432] 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, Abbe number, and aspherical coefficient of each lens are not limited to the values ​​shown in the above embodiments, and other values ​​may be used.

[0433] Furthermore, the imaging device involved in the embodiments of the present invention is not limited to the examples described above, and can be configured in various ways, such as a camera other than a mirrorless camera, a film camera, a video camera, and a security camera.

[0434] The following notes further disclose the above-described implementation methods and embodiments.

[0435] [Postscript 1]

[0436] An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, and a second lens group, wherein,

[0437] During focusing, the imaging lens moves as a whole, or a portion of the first lens group, the aperture, and the second lens group moves.

[0438] 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 is set to f1,

[0439] The imaging lens satisfies the following conditional expression (1):

[0440] 0.1 <f / f1<1.5(1)。

[0441] [Postscript 2]

[0442] According to the imaging lens described in Appendix 1, wherein,

[0443] The first lens group includes at least one positive lens.

[0444] When the focal length of the strongest positive lens among the positive lenses included in the first lens group is set to fp1,

[0445] The imaging lens satisfies the following condition (2):

[0446] 0.1 <f / fp1<4(2)。

[0447] [Postscript 3]

[0448] According to the imaging lens described in Appendix 1 or 2, wherein,

[0449] The first lens group includes at least one positive lens and at least one negative lens.

[0450] The focal length of the positive lens closest to the object in the first lens group is set to fp1F.

[0451] When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1,

[0452] The imaging lens satisfies the following condition (3):

[0453] 0.3 <fp1F / |fn1|<6 (3)。

[0454] [Postscript 4]

[0455] The imaging lens according to any one of Appendices 1 to 3, wherein,

[0456] The second lens group includes at least one negative lens.

[0457] When the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group is set to fn2,

[0458] The imaging lens satisfies the following condition (4):

[0459] 0.3 <f / |fn2|<6 (4)。

[0460] [Postscript 5]

[0461] The imaging lens according to any one of Appendices 1 to 4, wherein,

[0462] The first lens group includes at least one positive lens and at least one negative lens.

[0463] The focal length of the positive lens with the strongest optical power among the positive lenses included in the first lens group is set as fp1.

[0464] When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1,

[0465] The imaging lens satisfies the following condition (5):

[0466] 0.15 <fp1 / |fn1|<6(5)。

[0467] [Postscript 6]

[0468] The imaging lens according to any one of Appendices 1 to 5, wherein,

[0469] The first lens group includes at least one positive lens.

[0470] Let the radius of curvature of the object-side surface of the positive lens with the highest optical power among the positive lenses included in the first lens group be Rf.

[0471] If the radius of curvature of the image-side surface of the positive lens with the highest optical power among the positive lenses included in the first lens group is set to Rr, then...

[0472] The imaging lens satisfies the following condition (6):

[0473] 0.05<(Rr+Rf) / (Rr-Rf)<6(6).

[0474] [Postscript 7]

[0475] The imaging lens according to any one of Appendices 1 to 6, wherein,

[0476] The first lens group includes at least one positive lens.

[0477] When the focal length of the strongest positive lens among the positive lenses included in the first lens group is set to fp1,

[0478] The imaging lens satisfies the following condition (7):

[0479] 0.3 <f1 / fp1<4.5(7)。

[0480] [Postscript 8]

[0481] The imaging lens according to any one of Appendices 1 to 7, wherein,

[0482] The first lens group includes at least one negative lens.

[0483] The second lens group includes at least one negative lens.

[0484] The focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set as fn1.

[0485] When the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group is set to fn2,

[0486] The imaging lens satisfies the following condition (8):

[0487] 0.1 <fn1 / fn2<6(8)。

[0488] [Postscript 9]

[0489] The imaging lens according to any one of Appendices 1 to 8, wherein,

[0490] The first lens group includes at least one negative lens.

[0491] When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1,

[0492] The imaging lens satisfies the following condition (9):

[0493] 0.2 <f / |fn1|<5(9)。

[0494] [Postscript 10]

[0495] The imaging lens according to any one of Appendices 1 to 9, wherein,

[0496] The lens surface closest to the image side of the first lens group is concave.

[0497] The lens surface of the second lens group closest to the object is concave.

[0498] [Postscript 11]

[0499] The imaging lens according to any one of Appendices 1 to 10, wherein,

[0500] The first lens group includes two or more positive lenses.

[0501] [Postscript 12]

[0502] The imaging lens according to any one of Appendices 1 to 11, wherein,

[0503] A positive meniscus lens with its convex surface facing the object side is disposed on the object side of the first lens group.

[0504] [Postscript 13]

[0505] The imaging lens according to any one of Appendices 1 to 12, wherein,

[0506] The first lens group includes at least one positive lens.

[0507] When the refractive index of the positive lens closest to the object in the first lens group is set to Np1F relative to the d-line,

[0508] The imaging lens satisfies the following conditional expression (10):

[0509] 1.5 <Np1F<2.03 (10)。

[0510] [Postscript 14]

[0511] The imaging lens according to any one of Appendices 1 to 13, wherein,

[0512] The second lens group includes at least one lens surface with poles.

[0513] The pole is a point on the lens surface other than the optical axis, and the tangent of the lens surface at the pole intersects the optical axis perpendicularly.

[0514] [Postscript 15]

[0515] The imaging lens according to any one of Appendices 1 to 14, wherein,

[0516] The second lens group includes a front part and a rear part from the object side to the image side.

[0517] During focusing, the first lens group, the aperture, and the front part group move as a whole, while the rear part group remains fixed relative to the image plane.

[0518] [Postscript 16]

[0519] According to the imaging lens described in Appendix 15, wherein,

[0520] The rear portion group includes one or more lenses, each lens including at least one lens surface with a pole.

[0521] The pole is a point on the lens surface other than the optical axis, and the tangent of the lens surface at the pole intersects the optical axis perpendicularly.

[0522] [Postscript 17]

[0523] According to the imaging lens described in Appendix 16, wherein,

[0524] The rear portion group includes two or more lenses, and each lens includes at least one lens surface having the pole.

[0525] [Postscript 18]

[0526] The imaging lens according to any one of Appendices 15 to 17, wherein,

[0527] When the sum of the air gaps on the optical axis within the rear portion group is set to D2Rair, and the distance on the optical axis from the lens surface closest to the object side of the rear portion group to the lens surface closest to the image side of the rear portion group is set to D2R,

[0528] The imaging lens satisfies the following conditional expression (11):

[0529] 0≤D2Rair / D2R<0.45(11).

[0530] [Postscript 19]

[0531] The imaging lens according to any one of Appendices 15 to 18, wherein,

[0532] The distance along the optical axis from the lens surface closest to the object side of the rear part group to the lens surface closest to the image side of the rear part group is defined as D2R.

[0533] When focusing on an object at infinity, the distance along the optical axis from the lens surface of the first lens group closest to the object to the lens surface of the rear part group closest to the image is set to DT.

[0534] The imaging lens satisfies the following conditional expression (12):

[0535] 0.05 <D2R / DT<0.5(12)。

[0536] [Postscript 20]

[0537] A camera device comprising an imaging lens as described in any one of Appendices 1 to 19.

Claims

1. An imaging lens, comprising, from the object side to the image side, a first lens group, an aperture, and a second lens group, wherein, During focusing, the imaging lens moves as a whole, or a portion of the first lens group, the aperture, and the second lens group moves. 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 is set to f1, The imaging lens satisfies the following conditional expression (1): 0.1 <f / f1<1.5 (1)。 2. The imaging lens according to claim 1, wherein, The first lens group includes at least one positive lens. When the focal length of the strongest positive lens among the positive lenses included in the first lens group is set to fp1, The imaging lens satisfies the following condition (2): 0.1 <f / fp 1<4(2)。 3. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one positive lens and at least one negative lens. The focal length of the positive lens closest to the object in the first lens group is set to fplF. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1, The imaging lens satisfies the following condition (3): 0.3 <fplF / fnl|<6(3)。 4. The imaging lens according to claim 1 or 2, wherein, The second lens group includes at least one negative lens. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group is set to fn2, The imaging lens satisfies the following condition (4): 0.3 <f / fn2 |<6(4)。 5. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one positive lens and at least one negative lens. The focal length of the positive lens with the strongest optical power among the positive lenses included in the first lens group is set as fp1. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fn1, The imaging lens satisfies the following condition (5): 0.15 <fp1 / fn1|<6(5)。 6. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one positive lens. Let the radius of curvature of the object-side surface of the positive lens with the highest optical power among the positive lenses included in the first lens group be Rf. If the radius of curvature of the image-side surface of the positive lens with the highest optical power among the positive lenses included in the first lens group is set to Rr, then... The imaging lens satisfies the following condition (6): 0.05<(Rr+Rf) / (Rr-Rf)<6 (6).

7. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one positive lens. When the focal length of the strongest positive lens among the positive lenses included in the first lens group is set to fp1, The imaging lens satisfies the following condition (7): 0.3 <f1 / fpl<4.5 (7)。 8. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one negative lens. The second lens group includes at least one negative lens. The focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fnl. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the second lens group is set to fn2, The imaging lens satisfies the following condition (8): 0.1 <fnl / fn2<6 (8)。 9. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one negative lens. When the focal length of the negative lens with the strongest optical power among the negative lenses included in the first lens group is set to fnl, The imaging lens satisfies the following condition (9): 0.2 <f / fnl|<5(9)。 10. The imaging lens according to claim 1 or 2, wherein, The lens surface closest to the image side of the first lens group is concave. The lens surface of the second lens group closest to the object is concave.

11. The imaging lens according to claim 1 or 2, wherein, The first lens group includes two or more positive lenses.

12. The imaging lens according to claim 1 or 2, wherein, A positive meniscus lens with its convex surface facing the object side is disposed on the object side of the first lens group.

13. The imaging lens according to claim 1 or 2, wherein, The first lens group includes at least one positive lens. When the refractive index of the positive lens closest to the object in the first lens group is set to NplF relative to the d-line, The imaging lens satisfies the following conditional expression (10): 1.5 <Np1F<2.03 (10)。 14. The imaging lens according to claim 1 or 2, wherein, The second lens group includes at least one lens surface with poles. The pole is a point on the lens surface other than the optical axis, and the tangent of the lens surface at the pole intersects the optical axis perpendicularly.

15. The imaging lens according to claim 1 or 2, wherein, The second lens group includes a front part and a rear part from the object side to the image side. During focusing, the first lens group, the aperture, and the front part group move as a whole, while the rear part group remains fixed relative to the image plane.

16. The imaging lens according to claim 15, wherein, The rear portion group includes one or more lenses, each lens including at least one lens surface having a pole. The pole is a point on the lens surface other than the optical axis, and the tangent of the lens surface at the pole intersects the optical axis perpendicularly.

17. The imaging lens according to claim 16, wherein, The rear portion group includes two or more lenses, each lens including at least one lens surface having the pole.

18. The imaging lens according to claim 16, wherein, The sum of the air gaps on the optical axis within the rear section group is set as D2Rair. If the distance along the optical axis from the lens surface closest to the object side of the rear part group to the lens surface closest to the image side of the rear part group is defined as D2R, The imaging lens satisfies the following conditional expression (11): 0≤D2Rair / D2R<0.45 (11).

19. The imaging lens according to claim 18, wherein, When focusing on an object at infinity, the distance along the optical axis from the lens surface of the first lens group closest to the object to the lens surface of the rear part group closest to the image is set to DT. The imaging lens satisfies the following conditional expression (12): 0.05 <D2R / DT<0.5 (12)。 20. A camera device comprising an imaging lens according to any one of claims 1 to 19.

Images