Imaging lens, imaging device, and mobile body

Abstract

To provide an imaging lens with improved optical performance. [Solution] The imaging lens 10 according to this disclosure comprises a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, the front lens group being composed of four lenses including two or fewer lenses having negative refractive power, and the rear lens group being composed of three lenses including one or fewer lenses having negative refractive power.

Description

Technical Field

[0001] The present disclosure relates to an imaging lens, an imaging device, and a moving body.

Background Art

[0002] Conventionally, in order to provide an imaging lens that is small, lightweight, resistant to environmental changes, and has good imaging performance across the entire screen for applications such as surveillance cameras and in-vehicle cameras, development has been carried out. For example, Patent Document 1 discloses a lens unit with high chromatic aberration correction accuracy in a wide temperature range.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in recent years, surveillance cameras and in-vehicle cameras have added a sensing function for detecting objects from conventional visual recognition applications, and image sensors are also becoming more highly pixelated. Therefore, imaging lenses are required to have even higher optical performance while being small, lightweight, and inexpensive.

[0005] Therefore, the object of the present disclosure, which focuses on these points, is to provide an imaging lens having high optical performance, as well as an imaging device and a moving body using the same.

Means for Solving the Problems

[0006] The imaging lens according to one embodiment of the present disclosure is (1) The device comprises a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, the front lens group consisting of four lenses including two or fewer lenses having negative refractive power, and the rear lens group consisting of three lenses including one or fewer lenses having negative refractive power.

[0007] (2) The imaging lens described in (1) above, The front lens group may consist of a first lens having negative refractive power, a second lens having negative refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power, arranged in order from the object side, while the rear lens group may consist of a fifth lens having positive refractive power, a sixth lens having positive refractive power, and a seventh lens having negative refractive power, arranged in order from the object side.

[0008] (3) The OTO lens described in (2) above, If R1 is the radius of curvature of the object side of the first lens, R2 is the radius of curvature of the image side of the first lens, R11 is the radius of curvature of the object side of the sixth lens, R12 is the radius of curvature of the image side of the sixth lens, D2 is the on-axial distance from the image side of the first lens to the object side of the second lens, f is the focal length of the imaging lens with respect to the d line, and D1 is the on-axial thickness of the first lens, then the conditional equation is, 1.9 < (R1 + R2) / (R1 - R2) < 2.1 (1) 0.2<(R11+R12) / (R11-R12)<0.4 (2) 0.4 <D2 / f<0.6 (3) 0.1 <D1 / f<0.3 (4) It is acceptable to satisfy this condition.

[0009] (4) The imaging lens described in (3) above, If R6 is the radius of curvature of the image surface of the third lens, then the conditional equation is: 3.2 <R1 / f<3.4 (5) -5 <R6 / f<-3.7 (6) 3.2 <R11 / f<4.1 (7) may be satisfied.

[0010] (5) The imaging lens according to (3) or (4) above, the image side surface of the third lens is convex, Let the Abbe number of the first lens with respect to the d-line be ν1, the refractive index of the first lens with respect to the d-line be n1, and the refractive index of the seventh lens with respect to the d-line be n7. Then, the conditional expressions, 12 < ν1 / f < 12.3 (8) 0.3 < n1 / f < 0.4 (9) 0.3 < n7 / f < 0.4 (10) may be satisfied.

[0011] (6) The imaging lens according to any one of (3) to (5) above, Let the focal length of the first lens with respect to the d-line be f1 and the focal length of the second lens with respect to the d-line be f2. Then, the conditional expressions, -2.5 < f1 / f < -2.2 (11) -1.4 < f2 / f < -1.2 (12) may be satisfied.

[0012] (7) The imaging lens according to (2) above, the object side surface of the fourth lens is convex, Let the focal length of the imaging lens with respect to the d-line be f, the on-axis distance from the image side surface of the first lens to the object side surface of the second lens be D2, the radius of curvature of the object side surface of the second lens be R3, and the radius of curvature of the image side surface of the second lens be R4. Then, the conditional expressions, 3.3 < R7 / f < 4.3 (13) 0 < D2 / f < 0.2 (14) -0.2 < (R3 + R4) / (R3 - R4) < 0 (15) may be satisfied.

[0013] (8) The imaging lens according to (7) above, Let the radius of curvature of the object side surface of the seventh lens be R13, the radius of curvature of the image side surface of the seventh lens be R14, the on-axis thickness of the second lens be D3, and the radius of curvature of the image side surface of the first lens be R2. Then, the conditional expressions -0.7 < (R13 + R14) / (R13 - R14) < -0.5 (16) 0.2 < D3 / f < 0.3 (17) 1 < R2 / f < 1.2 (18) may be satisfied.

[0014] (9) The imaging lens according to (7) or (8) above, Let the radius of curvature of the image side surface of the sixth lens be R12, the radius of curvature of the object side surface of the seventh lens be R13, the Abbe number of the second lens with respect to the d-line be ν2, and the refractive index of the second lens with respect to the d-line be n2. Then, the conditional expressions -2 < R12 / f < -1.9 (19) -2 < R13 / f < -1.9 (20) 6.8 < ν2 / f < 6.9 (21) 0.3 < n2 / f < 0.4 (22) may be satisfied.

[0015] (10) The imaging lens according to any one of (7) to (9) above, Let the focal length of the fourth lens with respect to the d-line be f4, and the focal length of the fifth lens with respect to the d-line be f5. Then, the conditional expressions 2.8 < f4 / f < 3 (23) 2.1 < f5 / f < 2.3 (24) may be satisfied.

[0016] (11) The imaging lens according to (2) above, Let the radius of curvature of the object side surface of the third lens be R5, the radius of curvature of the image side surface of the third lens be R6, the refractive index of the third lens with respect to the d-line be n3, the focal length of the imaging lens with respect to the d-line be f, the focal length of the fourth lens with respect to the d-line be f4, and the radius of curvature of the image side surface of the fourth lens be R8. Then, the conditional expressions 0 < (R5 + R6) / (R5 - R6) < 0.2 (25) 0.3 <n3 / f<0.4 (26) 2.8 <f4 / f<3 (27) -4.3 <R8 / f<-3.4 (28) It is acceptable to satisfy this condition.

[0017] (12) The imaging lens described in (11) above, If we let ν3 be the Abbe number of the third lens with respect to the d line, ν6 be the Abbe number of the sixth lens with respect to the d line, and D5 be the on-axial thickness of the third lens, then the conditional equation is: 5.8 < ν³ / f < 5.9 (29) 14.4 < ν6 / f < 14.5 (30) 0.7 <D5 / f<0.9 (31) It is acceptable to satisfy this condition.

[0018] (13) The imaging lens described in (11) or (12) above, The object side of the second lens is concave, If the on-axial thickness of the sixth lens is D12, the on-axial distance from the image side of the third lens to the object side of the fourth lens is D6, and the radius of curvature of the object side of the second lens is R3, then the conditional equation is: 0.5 <D12 / f<0.6 (32) 0 <D6 / f<0.1 (33) -1.8 <R3 / f<-1.5 (34) It is acceptable to satisfy this condition.

[0019] (14) An imaging lens as described in any one of (11) to (13) above, If the focal length of the third lens with respect to the d line is f3 and the focal length of the fifth lens with respect to the d line is f5, then the conditional equation is, 2.9 <f3 / f<3.4 (35) 2.1 <f5 / f<2.3 (36) It is acceptable to satisfy this condition.

[0020] (15) The OTO lens described in (2) above, If R7 is the radius of curvature of the object side of the fourth lens, R8 is the radius of curvature of the image side of the fourth lens, R9 is the radius of curvature of the object side of the fifth lens, f is the focal length of the imaging lens with respect to the d line, and D10 is the on-axial thickness of the fifth lens, then the conditional equation is: -0.1 < (R7 + R8) / (R7 - R8) < 0.1 (37) 2.4 <R9 / f<2.6 (38) 1 <D10 / f<1.2 (39) It is acceptable to satisfy this condition.

[0021] (16) The imaging lens described in (15) above, Each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens is made of glass material. If the refractive index of the fourth lens with respect to the d line is n4 and the on-axial thickness of the seventh lens is D14, then the conditional equation is: 0.3 <n4 / f<0.4 (40) 0.1 <D14 / f<0.4 (41) It is acceptable to satisfy this condition.

[0022] (17) The imaging lens described in (15) or (16) above, The image side and object side of the fifth lens are formed as aspherical shapes. The sixth lens and the seventh lens are formed as a cemented lens. If D89 is the on-axial distance from the image side of the fourth lens to the object side of the fifth lens, and R4 is the radius of curvature of the image side of the second lens, then the conditional equation is: 1.1 <D89 / f<1.3 (42) 2 <R4 / f<2.2 (43) It is acceptable to satisfy this condition.

[0023] (18) An imaging lens as described in any one of (15) to (17) above, If the focal length of the sixth lens with respect to the d line is f6 and the focal length of the seventh lens with respect to the d line is f7, then the conditional equation is, 2 <f6 / f<2.3 (44) -2 <f7 / f<-1.7 (45) It is acceptable to satisfy this condition.

[0024] (19) The OTO lens described in (2) above, The object side and image side of the fifth lens are formed as aspherical shapes. If R9 is the radius of curvature of the object side of the fifth lens, R10 is the radius of curvature of the image side of the fifth lens, D7 is the on-axial thickness of the fourth lens, f is the focal length of the imaging lens with respect to the d line, and D11 is the on-axial distance from the image side of the fifth lens to the object side of the sixth lens, then the conditional equation is: 0.1<(R9+R10) / (R9-R10)<0.3 (46) 0.6 <D7 / f<0.8 (47) 0 <D11 / f<0.1 (48) It is acceptable to satisfy this condition.

[0025] (20) The imaging lens described in (19) above, The sixth lens and the seventh lens are formed as a cemented lens. The object side of the third lens is convex, If R5 is the radius of curvature of the object side of the third lens, then the conditional equation is: 4.1 <R5 / f<5.2 (49) It is acceptable to satisfy this condition.

[0026] (twenty one) The OTO lens described in (19) or (20) above, The image surface of the seventh lens is concave. If the refractive index of the fifth lens with respect to the d line is n5, the radius of curvature of the image surface of the fifth lens is R10, and the Abbe number of the fifth lens with respect to the d line is ν5, then the conditional equation is, 0.3 <n5 / f<0.4 (50) -1.8 <R10 / f<-1.5 (51) 17 < ν5 / f < 18 (52) It is acceptable to satisfy this condition.

[0027] (twenty two) An imaging lens as described in any one of (19) to (21) above, If the focal length of the seventh lens with respect to the d line is f7 and the focal length of the second lens with respect to the d line is f2, then the conditional equation is, -2 <f7 / f<-1.7 (53) -1.4 <f2 / f<-1.2 (54) It is acceptable to satisfy this condition.

[0028] An imaging apparatus according to one embodiment of the present disclosure, (twenty three) An imaging lens comprising a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, wherein the front lens group consists of four lenses including two or fewer lenses having negative refractive power, and the rear lens group consists of three lenses including one or fewer lenses having negative refractive power, An image sensor that converts the optical image formed through the aforementioned imaging lens into an electrical signal. It is equipped with.

[0029] (twenty four) A mobile body according to one embodiment of this disclosure is An imaging lens comprising a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, wherein the front lens group consists of four lenses including two or fewer lenses having negative refractive power, and the rear lens group consists of three lenses including one or fewer lenses having negative refractive power, An image sensor that converts the optical image formed through the aforementioned imaging lens into an electrical signal. It has an imaging device equipped with the following features. [Effects of the Invention]

[0030] According to one embodiment of the present disclosure, the imaging lens, imaging device, and moving body can improve optical performance. [Brief explanation of the drawing]

[0031] [Figure 1] This is a lens configuration diagram of the imaging lens according to Embodiment 1 of the present disclosure. [Figure 2A] Figure 1 is a graph showing the astigmatism of the imaging lens. [Figure 2B] Figure 1 is a graph showing the distortion aberration of the imaging lens. [Figure 2C] Figure 1 is a graph showing the spherical aberration of the imaging lens. [Figure 3] This is a lens configuration diagram of the imaging lens according to Embodiment 2 of the present disclosure. [Figure 4A] Figure 2 is a graph showing the astigmatism of the imaging lens. [Figure 4B] Figure 2 is a graph showing the distortion aberration of the imaging lens. [Figure 4C] Figure 2 is a graph showing the spherical aberration of the imaging lens. [Figure 5] This is a lens configuration diagram of the imaging lens according to Embodiment 3 of the present disclosure. [Figure 6A] Figure 5 is a graph showing the astigmatism of the imaging lens. [Figure 6B] Figure 5 is a graph showing the distortion aberration of the imaging lens. [Figure 6C] Figure 5 is a graph showing the spherical aberration of the imaging lens. [Figure 7] This is a lens configuration diagram of the imaging lens according to Embodiment 4 of the present disclosure. [Figure 8A] Figure 7 is a graph showing the astigmatism of the imaging lens. [Figure 8B] Figure 7 is a graph showing the distortion aberration of the imaging lens. [Figure 8C] Figure 7 is a graph showing the spherical aberration of the imaging lens. [Figure 9] This is a lens configuration diagram of the imaging lens according to Embodiment 5 of the present disclosure. [Figure 10A]Figure 9 is a graph showing the astigmatism of the imaging lens. [Figure 10B] Figure 9 is a graph showing the distortion aberration of the imaging lens. [Figure 10C] Figure 9 is a graph showing the spherical aberration of the imaging lens. [Figure 11] This is a lens configuration diagram of the imaging lens according to Embodiment 6 of the present disclosure. [Figure 12A] Figure 11 is a graph showing the astigmatism of the imaging lens. [Figure 12B] Figure 11 is a graph showing the distortion aberration of the imaging lens. [Figure 12C] Figure 11 is a graph showing the spherical aberration of the imaging lens. [Figure 13] This is a lens configuration diagram of the imaging lens according to Embodiment 7 of the present disclosure. [Figure 14A] Figure 13 is a graph showing the astigmatism of the imaging lens. [Figure 14B] Figure 13 is a graph showing the distortion aberration of the imaging lens. [Figure 14C] Figure 13 is a graph showing the spherical aberration of the imaging lens. [Figure 15] This is a lens configuration diagram of the imaging lens according to Embodiment 8 of the present disclosure. [Figure 16A] Figure 15 is a graph showing the astigmatism of the imaging lens. [Figure 16B] Figure 15 is a graph showing the distortion aberration of the imaging lens. [Figure 16C] Figure 15 is a graph showing the spherical aberration of the imaging lens. [Modes for carrying out the invention]

[0032] Embodiments relating to this disclosure will be described below with reference to the drawings.

[0033] The following description will explain an imaging lens 10 and imaging device 1 according to one embodiment, with appropriate use of the drawings. In each attached drawing showing the configuration of the imaging lens 10 and imaging device 1, the "object side" corresponds to the left side and the "image side" corresponds to the right side. The figures used in the following description are schematic, and the dimensional ratios shown in the drawings do not necessarily correspond to those in reality.

[0034] (Imaging device 1) As shown in Figure 1, the imaging device 1 includes an imaging lens 10 and an image sensor 20 that converts the optical image formed through the imaging lens 10 into an electrical signal. For example, the image sensor 20 includes solid-state image sensors such as charge-coupled devices (CCDs) and complementary metal-oxide-semiconductors (CMOSs). The image sensor 20 has an image plane 21 on its surface. The imaging device 1 images an object by having the imaging lens 10 form an image of the object onto the image plane 21 of the image sensor 20. For example, the imaging device 1 can be used for video recording, which involves continuously repeating image capture. More specifically, for example, the imaging device 1 can be used in surveillance cameras or in-vehicle cameras. When the imaging device 1 is used in an in-vehicle camera, for example, the imaging device 1 is located in at least one of the side, front, and rear of a vehicle equipped with a control device that controls the imaging device 1. In other words, the imaging device 1 captures images of at least one of the vehicle's sides, front, and rear.

[0035] (Imaging lens 10) The imaging lens 10 has a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170. In addition to the first to seventh lenses 110 to 170, the imaging lens 10 may also have lenses that have substantially no refractive power, as well as other optical elements other than lenses, including an aperture and a cover glass. For example, in addition to the first to seventh lenses 110 to 170, the imaging lens 10 has an aperture diaphragm 180 and a flat plate 190.

[0036] The imaging lens 10 has a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture diaphragm 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170, arranged in order from the object side to the image side. The imaging lens 10 is a fixed-focus imaging lens with a seven-element configuration. The imaging lens 10 may also have a flat plate 190 located on the image side of the seventh lens 170. The first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 constitute the front lens group. The front lens group consists of four lenses, including up to two lenses with negative refractive power. The fifth lens 150, the sixth lens 160, and the seventh lens 170 constitute the rear lens group. The rear lens group consists of three lenses, including up to one lens with negative refractive power.

[0037] In one embodiment, the first lens 110 has a negative refractive power. The second lens 120 has a negative refractive power. The third lens 130 has a positive refractive power. The fourth lens 140 has a positive refractive power. The fifth lens 150 has a positive refractive power. The sixth lens 160 has a positive refractive power. The seventh lens 170 has a negative refractive power.

[0038] In one embodiment, the first lens 110 has a spherical shape. The object-side surface of the first lens 110 is convex. The image-side surface of the first lens 110 is concave. The second lens 120 has a spherical shape. The object-side surface and the image-side surface of the second lens 120 are concave. The third lens 130 has a spherical shape. The object-side surface and the image-side surface of the third lens 130 are convex. The fourth lens 140 has a spherical shape. The object-side surface and the image-side surface of the fourth lens 140 are convex. The object-side surface and the image-side surface of the fifth lens 150 are aspherical. The object-side surface and the image-side surface of the fifth lens 150 are convex. The sixth lens 160 has a spherical shape. The object-side surface and the image-side surface of the sixth lens 160 are convex. The seventh lens 170 has a spherical shape. The object-side and image-side surfaces of the seventh lens 170 are concave.

[0039] The imaging lens 10 has two positive refractive lenses positioned before and after the aperture diaphragm 180, resulting in a more symmetrical arrangement around the aperture diaphragm 180. As a result, the back focus is shorter than that of a typical retrofocus lens. This configuration allows the imaging lens 10 to relax the constraints on each lens and achieve good aberration correction with only one aspherical lens, the fifth lens 150. Consequently, the imaging lens 10 can be constructed at a lower cost than imaging lenses that use multiple aspherical lenses.

[0040] The aperture diaphragm 180 is located between the fourth lens 140 and the fifth lens 150. Placing the aperture diaphragm 180 closer to the image than the fifth lens 150 is undesirable because it would increase the size of the lens system. Also, placing the aperture diaphragm 180 closer to the object than the fourth lens 140 is undesirable because it would make it difficult to widen the angle of the imaging lens 10. Therefore, by placing the aperture diaphragm 180 between the fourth lens 140 and the fifth lens 150, it is possible to correct various aberrations well and make the lens system more compact.

[0041] The sixth lens 160 and the seventh lens 170 may be formed as a cemented lens. The image-side surface of the sixth lens 160 and the object-side surface of the seventh lens 170 may be in contact. For example, the sixth lens 160 and the seventh lens 170 may be joined together with an adhesive.

[0042] Each of the first to seventh lenses 110 to 170 may be made of glass material. This makes it possible to reduce yellowing due to ultraviolet light and changes in optical properties due to temperature changes. Each of the first to seventh lenses 110 to 170 may be made of glass material with a different refractive index. The material of the first to seventh lenses 110 to 170 is not limited to glass. For example, only one of the first to seventh lenses 110 to 170 may be made of a material other than glass. For example, only one of the first to seventh lenses 110 to 170 may be made of a resin material or the like.

[0043] For example, the flat plate 190 may be an optical filter that reduces the amount of light transmitted in a predetermined wavelength band. For example, the flat plate 190 may be composed of an optical element such as an infrared cut filter or an ultraviolet cut filter. If the flat plate 190 is composed of an infrared cut filter, for example, the flat plate 190 can reduce the effect of infrared rays on the image plane 21. If the flat plate 190 is composed of an ultraviolet cut filter, for example, the flat plate 190 can reduce the effect of ultraviolet rays on the image sensor 20. For example, the material of the infrared cut filter and the ultraviolet cut filter may be glass.

[0044] In one embodiment, the imaging lens 10 may satisfy the following conditions (1) to (4). 1.9 < (R1 + R2) / (R1 - R2) < 2.1 (1) 0.2<(R11+R12) / (R11-R12)<0.4 (2) 0.4 <D2 / f<0.6 (3) 0.1 <D1 / f<0.3 (4) However, R1 is the radius of curvature of the object side of the first lens 110. R2 is the radius of curvature of the image side of the first lens 110. R11 is the radius of curvature of the object side of the sixth lens 160. R12 is the radius of curvature of the image side of the sixth lens 160. D2 is the on-axial distance from the image side of the first lens 110 to the object side of the second lens 120. f is the focal length of the imaging lens 10 with respect to the d line. D1 is the on-axial thickness of the first lens 110.

[0045] Conditional equation (1) relates the radius of curvature R1 of the object side of the first lens 110 to the radius of curvature R2 of the image side. If the value of (R1+R2) / (R1-R2) is greater than or equal to the upper limit of 2.1, the absolute value of the difference in radii of curvature becomes too small, resulting in large axial chromatic aberration. If the value of (R1+R2) / (R1-R2) is less than or equal to the lower limit of 1.9, the absolute value of the difference in radii of curvature becomes too large, resulting in excessive refractive power of the first lens 110 and large over-spherical aberration. By satisfying conditional equation (1), the occurrence of axial chromatic aberration and spherical aberration can be suppressed.

[0046] Conditional equation (2) relates the radius of curvature R11 on the object side of the sixth lens 160 to the radius of curvature R12 on the image side. If the value of (R11+R12) / (R11-R12) is greater than or equal to the upper limit of 0.4, the absolute value of the difference in radii of curvature becomes too large, causing excessive spherical aberration. If the value of (R11+R12) / (R11-R12) falls below the lower limit of 0.2, the refractive power of the sixth lens 160 is too large, causing significant axial chromatic aberration. By satisfying conditional equation (2), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0047] Conditional equation (3) is an equation that relates the on-axial distance D2 from the image side of the first lens 110 to the object side of the second lens 120 to the focal length f of the imaging lens 10 with respect to the d line. If the value of D2 / f is 0.6 or higher, which is the upper limit, the distance between the first lens 110, which has negative refractive power, and the lenses from the second lens 120 onward becomes too wide, causing significant astigmatism. If the value of D2 / f is 0.4 or lower, which is the lower limit, the distance between the first lens 110, which has negative refractive power, and the lenses from the second lens 120 onward becomes too narrow, causing the meridional image plane to tilt to the under-focused side. By satisfying conditional equation (3), the occurrence of astigmatism can be suppressed, and the tilting of the meridional image plane to the under-focused side can be suppressed.

[0048] Conditional equation (4) is an equation that relates the axial thickness D1 of the first lens 110 to the focal length f of the imaging lens 10 with respect to the d line. If the value of dropD1 / f is greater than or equal to the upper limit of 0.3, the axial thickness D1 of the first lens 110, which has negative refractive power, becomes too thick, causing the refractive power to become too small and resulting in large astigmatism. If the value of D1 / f is less than or equal to the lower limit of 0.1, the axial thickness D1 of the first lens 110, which has negative refractive power, becomes too thin, causing the refractive power to become too large and resulting in large lateral chromatic aberration at intermediate image heights. By satisfying conditional equation (4), the occurrence of astigmatism and lateral chromatic aberration can be suppressed.

[0049] Furthermore, the imaging lens 10 may satisfy the following conditions (5) to (7). 3.2 <R1 / f<3.4 (5) -5 <R6 / f<-3.7 (6) 3.2 <R11 / f<4.1 (7) However, R1 is the radius of curvature of the object side of the first lens 110. f is the focal length of the imaging lens 10 with respect to the d line. R6 is the radius of curvature of the image side of the third lens 130. R11 is the radius of curvature of the object side of the sixth lens 160.

[0050] Conditional equation (5) is an equation that relates the radius of curvature R1 of the object side surface of the first lens 110 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R1 / f is 3.4 or higher, the object side surface of the first lens 110 approaches a plane, and the meridional image plane tilts to the under-side. When the value of R1 / f is 3.2 or lower, the radius of curvature R1 of the object side surface of the first lens 110 becomes smaller, and the meridional image plane tilts to the over-side. By satisfying conditional equation (5), it is possible to suppress the meridional image plane from tilting to the under-side or over-side.

[0051] Conditional equation (6) is an equation that relates the radius of curvature R6 of the image side of the third lens 130 to the focal length f of the imaging lens 10 with respect to the d line. If the value of R6 / f is greater than or equal to the upper limit of -3.7, the radius of curvature R6 of the image side of the third lens 130, which has positive refractive power, becomes too small, causing significant axial chromatic aberration. If the value of R6 / f is less than or equal to the lower limit of -5, the radius of curvature R6 of the image side of the third lens 130, which has positive refractive power, becomes too large, causing significant field curvature. When conditional equation (6) is satisfied, the occurrence of axial chromatic aberration and field curvature is suppressed.

[0052] Conditional equation (7) relates the radius of curvature R11 of the object side of the sixth lens 160 to the focal length f of the imaging lens 10 with respect to the d line. If the value of R11 / f is greater than or equal to the upper limit of 4.1, the radius of curvature R11 of the object side of the sixth lens 160, which has positive refractive power, becomes too large, causing the meridional image plane to tilt to the under-angle side. If the value of R11 / f is less than or equal to the lower limit of 3.2, the radius of curvature R11 of the object side of the sixth lens 60, which has positive refractive power, becomes too small, causing significant axial chromatic aberration. When conditional equation (7) is satisfied, the meridional image plane does not tilt to the under-angle side, and the occurrence of axial chromatic aberration is suppressed.

[0053] Furthermore, the image surface of the third lens 130 of the imaging lens 10 is convex, and the imaging lens 10 may satisfy the following conditions (8) to (10). 12 < ν 1 / f < 12.3 (8) 0.3 <n1 / f<0.4 (9) 0.3 <n7 / f<0.4 (10) However, ν1 is the Abbe number of the first lens 110 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. n1 is the refractive index of the first lens 110 with respect to the d line. n7 is the refractive index of the seventh lens 170 with respect to the d line.

[0054] By making the image surface of the third lens 130, which the light rays pass through first and second lenses 110 and 120 (both of which have negative refractive power), a convex surface, it becomes easier to focus the light rays, contributing to miniaturization.

[0055] Conditional equation (8) is an equation that relates the Abbe number ν1 of the first lens 110 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of ν1 / f is 12.3 or higher, the Abbe number ν1 of the first lens 110, which is a lens with negative refractive power, becomes too large, causing large chromatic aberration to occur on the overexposed side at peripheral image height. If the value of ν1 / f is 12 or lower, which is the lower limit, the Abbe number ν1 of the first lens 110, which is a lens with negative refractive power, becomes too small, causing large chromatic aberration to occur on the underexposed side at intermediate image height. By satisfying conditional equation (8), it is possible to suppress chromatic aberration to occur on the overexposed side at peripheral image height and chromatic aberration to occur on the underexposed side at intermediate image height.

[0056] Conditional equation (9) relates the refractive index n1 of the first lens 110 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of n1 / f is greater than or equal to the upper limit of 0.4, the refractive index n1 of the first lens 110, which is a lens with negative refractive power, becomes too high, causing the meridional image plane to tilt to the under-field. If the value of n1 / f is less than or equal to the lower limit of 0.3, the refractive index n1 of the first lens 110, which is a lens with negative refractive power, becomes too low, causing the meridional image plane to tilt to the over-field. When conditional equation (9) is satisfied, the tilting of the meridional image plane to the under-field or over-field is suppressed.

[0057] Conditional equation (10) is an equation that relates the refractive index n7 of the seventh lens 170 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of n7 / f is 0.4 or higher, the refractive index of the seventh lens 170, which has the closest negative refractive power to the image plane 21, becomes too high, causing excessive spherical aberration at peripheral image height. If the value of n7 / f is 0.3 or lower, the refractive index of the seventh lens 170, which has the closest negative refractive power to the image plane 21, becomes too low, causing axial chromatic aberration. By satisfying conditional equation (10), the occurrence of spherical aberration and axial chromatic aberration at peripheral image height can be suppressed.

[0058] Furthermore, the imaging lens 10 may satisfy the following conditions (11) and (12). -2.5 <f1 / f<-2.2 (11) -1.4 <f2 / f<-1.2 (12) However, f1 is the focal length of the first lens 110 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. f2 is the focal length of the second lens 120 with respect to the d line.

[0059] Conditional equation (11) relates the focal length f1 of the first lens 110 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f1 / f is greater than or equal to the upper limit of -2.2, the refractive power of the first lens 110 becomes too large, causing the meridional image plane to tilt to the under-angle side. If the value of f1 / f is less than or equal to the lower limit of -2.5, the refractive power of the first lens 110 becomes too small, causing significant axial chromatic aberration. When conditional equation (11) is satisfied, the meridional image plane does not tilt to the under-angle side, and the occurrence of axial chromatic aberration is suppressed.

[0060] Conditional equation (12) relates the focal length f2 of the second lens 120 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f2 / f is greater than or equal to the upper limit of -1.2, the refractive power of the second lens 120 becomes too large, causing the meridional image plane to tilt to the over-angle side. If the value of f2 / f is less than or equal to the lower limit of -1.4, the refractive power of the second lens 120 becomes too small, causing field curvature to occur to the under-angle side. By satisfying conditional equation (12), it is possible to suppress the meridional image plane from tilting to the over-angle side and the occurrence of field curvature.

[0061] In one embodiment, the object side surface of the fourth lens 140 is convex, and the imaging lens 10 may satisfy the following conditions (13) to (15). 3.3 <R7 / f<4.3 (13) 0 <D2 / f<0.2 (14) -0.2 < (R3 + R4) / (R3 - R4) < 0 (15) However, R7 is the radius of curvature of the object side of the fourth lens 140. f is the focal length of the imaging lens 10 with respect to the d line. D2 is the on-axial distance from the image side of the first lens 110 to the object side of the second lens 120. R3 is the radius of curvature of the object side of the second lens 120. R4 is the radius of curvature of the image side of the second lens 120.

[0062] By making the object-side surface of the fourth lens 140, which is the lens closest to the aperture diaphragm 180 and is on the object side, the light entering the aperture diaphragm 180 can be focused, making it easier to create a more compact configuration.

[0063] Conditional equation (13) relates the radius of curvature R7 of the object side of the fourth lens 140 to the focal length of the imaging lens 10 with respect to the d line. When the value of R7 / f is 4.3 or higher, the radius of curvature R7 of the object side of the fourth lens 140 becomes large, and spherical aberration occurs to the over-spherical side. When the value of R7 / f is 3.3 or lower, the radius of curvature R7 of the object side of the fourth lens 140 becomes small, and axial chromatic aberration occurs to a large extent. By satisfying conditional equation (13), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0064] Conditional equation (14) relates the on-axial distance D2 from the image side of the first lens 110 to the object side of the second lens 120 to the focal length f of the imaging lens 10 with respect to the d line. If the value of D2 / f is greater than or equal to the upper limit of 0.2, the distance between the second lens 120 and the third lens 130 is too long, resulting in a large refractive power for the entire optical system and causing spherical aberration to be underexposed. If the value of D2 / f is less than or equal to the lower limit of 0, the distance between the second lens 120 and the third lens 130 is too short, resulting in a small refractive power for the entire optical system and causing spherical aberration to be overexposed. By satisfying conditional equation (14), the occurrence of spherical aberration can be suppressed.

[0065] Conditional equation (15) relates the radius of curvature R3 of the object side of the second lens 120 to the radius of curvature R4 of the image side of the second lens 120. If the value of (R3+R4) / (R3-R4) is greater than or equal to the upper limit of 0, the difference in the absolute values ​​of the radii of curvature between the object side and the image side of the second lens 120 is too small, resulting in significant astigmatism. If the value of (R3+R4) / (R3-R4) is greater than or equal to the lower limit of -0.2, the difference in the absolute values ​​of the radii of curvature between the object side and the image side of the second lens 120 is too large, resulting in underexposure of spherical aberration. By satisfying conditional equation (15), the occurrence of astigmatism and spherical aberration can be suppressed.

[0066] Furthermore, the imaging lens 10 may satisfy the following conditions (16) to (18). -0.7<(R13+R14) / (R13-R14)<-0.5 (16) 0.2 <D3 / f<0.3 (17) 1 <R2 / f<1.2 (18) However, R13 is the radius of curvature of the object side of the seventh lens 170. R14 is the radius of curvature of the image side of the seventh lens 170. D3 is the on-axial thickness of the second lens 120. f is the focal length of the imaging lens 10 with respect to the d line. R2 is the radius of curvature of the image side of the first lens 110.

[0067] Conditional equation (16) relates the radius of curvature R13 of the object side of the seventh lens 170 to the radius of curvature R14 of the image side of the seventh lens 170. If the value of (R13+R14) / (R13-R14) is greater than or equal to the upper limit of -0.5, the difference in the absolute values ​​of the radii of curvature between the object side and the image side of the seventh lens 170 is too small, causing excessive spherical aberration. If the value of (R13+R14) / (R13-R14) is less than or equal to the lower limit of -0.7, the difference in the absolute values ​​of the radii of curvature between the object side and the image side of the seventh lens 170 is too large, causing significant axial chromatic aberration. By satisfying conditional equation (16), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0068] Conditional equation (17) relates the axial thickness D3 of the second lens 120 to the focal length f of the imaging lens 10 with respect to the d line. If the value of D3 / f is greater than or equal to the upper limit of 0.3, the axial thickness D3 of the second lens 120 is too thick, causing significant axial chromatic aberration. If the value of D3 / f is less than or equal to the lower limit of 0.2, the axial thickness D3 of the second lens 120 is too thin, causing excessive spherical aberration in the peripheral image height. By satisfying conditional equation (17), the occurrence of axial chromatic aberration and spherical aberration in the peripheral image height can be suppressed.

[0069] Conditional equation (18) relates the radius of curvature R2 of the image side of the first lens 110 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R2 / f is greater than or equal to the upper limit of 1.2, the radius of curvature R2 of the image side of the first lens 110 becomes large, and the meridional image plane becomes significantly overexposed. When the value of R2 / f is greater than or equal to the lower limit of 1, the radius of curvature R2 of the image side of the first lens 110 becomes small, and peripheral spherical aberration becomes significantly overexposed. By satisfying conditional equation (18), it is possible to suppress the significant overexposure of the meridional image plane and the significant overexposure of peripheral spherical aberration.

[0070] Furthermore, the imaging lens 10 may satisfy the following conditions (19) to (22). -2 <R12 / f<-1.9 (19) -2 <R13 / f<-1.9 (20) 6.8 < ν² / f < 6.9 (21) 0.3 <n2 / f<0.4 (22) However, R12 is the radius of curvature of the image side of the sixth lens 160. f is the focal length of the imaging lens 10 with respect to the d line. R13 is the radius of curvature of the object side of the seventh lens 170. ν2 is the Abbe number of the second lens 120 with respect to the d line. n2 is the refractive index of the second lens 120 with respect to the d line.

[0071] Conditional equation (19) relates the radius of curvature R12 of the image side of the sixth lens 160 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R12 / f is greater than or equal to the upper limit of -1.9, the absolute value of the radius of curvature R12 of the image side of the sixth lens 160 becomes small, and peripheral spherical aberration becomes large on the overexposure side. When the value of R12 / f is greater than or equal to the lower limit of -2, the absolute value of the radius of curvature R12 of the image side of the sixth lens 160 becomes large, and axial chromatic aberration becomes large. By satisfying conditional equation (19), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0072] Conditional equation (20) relates the radius of curvature R13 of the object side of the seventh lens 170 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R13 / f is greater than or equal to the upper limit of -1.9, the absolute value of the radius of curvature R13 of the object side of the seventh lens 170 becomes small, and peripheral spherical aberration becomes large on the overexposure side. When the value of R13 / f is less than or equal to the lower limit of -2, the absolute value of the radius of curvature R13 of the object side of the seventh lens 170 becomes large, and axial chromatic aberration becomes large. By satisfying conditional equation (20), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0073] Conditional equation (21) relates the Abbe number ν2 of the second lens 120 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. When the value of ν2 / f is 6.9 or higher, the Abbe number ν2 of the second lens 120 becomes high, and large axial chromatic aberration occurs where the focus of long wavelengths is on the over-focus side. When the value of ν2 / f is 6.8 or lower, the Abbe number ν2 of the second lens 120 becomes low, and large axial chromatic aberration occurs where the focus of short wavelengths is on the over-focus side. By satisfying conditional equation (21), the occurrence of axial chromatic aberration can be suppressed.

[0074] Conditional equation (22) relates the refractive index n2 of the second lens 120 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. When the value of n2 / f is 0.4 or higher, the refractive index n2 of the second lens 120 becomes high, and large field curvature occurs on the overexposure side. When the value of n2 / f is 0.3 or lower, the refractive index n2 of the second lens 120 becomes low, and large axial chromatic aberration occurs where the focus of long wavelengths is on the overexposure side. By satisfying conditional equation (22), the occurrence of field curvature and axial chromatic aberration can be suppressed.

[0075] Furthermore, the imaging lens 10 may satisfy the following conditions (23) and (24). 2.8 <f4 / f<3 (23) 2.1 <f5 / f<2.3 (24) However, f4 is the focal length of the fourth lens 140 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. f5 is the focal length of the fifth lens 150 with respect to the d line.

[0076] Conditional equation (23) relates the focal length f4 of the fourth lens 140 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f4 / f is greater than or equal to the upper limit of 3, the refractive power of the fourth lens 140 becomes too small, causing excessive spherical aberration at the peripheral image height. If the value of f4 / f is less than or equal to the lower limit of 2.8, the refractive power of the fourth lens 140 becomes too large, causing significant axial chromatic aberration. By satisfying conditional equation (23), the occurrence of spherical aberration and axial chromatic aberration at the peripheral image height can be suppressed.

[0077] Conditional equation (24) is an equation that relates the focal length f5 of the fifth lens 150 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f5 / f is 2.3 or higher, the refractive power of the fifth lens 150, which has positive refractive power on the image side of the aperture diaphragm 180, becomes too small, resulting in significant astigmatism. If the value of f5 / f is 2.1 or lower, which is the lower limit, the refractive power of the fifth lens 150, which has positive refractive power on the image side of the aperture diaphragm 180, becomes too large, resulting in underexposure of spherical aberration. By satisfying conditional equation (24), the occurrence of astigmatism and spherical aberration can be suppressed.

[0078] In one embodiment, the imaging lens 10 may satisfy the following conditions (25) to (28). 0 < (R5 + R6) / (R5 - R6) < 0.2 (25) 0.3 <n3 / f<0.4 (26) 2.8 <f4 / f<3 (27) -4.3 <R8 / f<-3.4 (28) However, R5 is the radius of curvature of the object side of the third lens 130. R6 is the radius of curvature of the image side of the third lens 130. n3 is the refractive index of the third lens 130 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. f4 is the focal length of the fourth lens 140 with respect to the d line. R8 is the radius of curvature of the image side of the fourth lens 140.

[0079] Conditional equation (25) relates the radius of curvature R5 of the object side of the third lens 130 to the radius of curvature R6 of the image side of the third lens 130. When the value of (R5+R6) / (R5-R6) is greater than or equal to the upper limit of 0.2, the difference in the absolute values ​​of the radii of curvature R5 of the object side of the third lens 130 and the radius of curvature R6 of the image side becomes large, causing significant over-spherical aberration. When the value of (R5+R6) / (R5-R6) is less than or equal to the lower limit of 0, the difference in the absolute values ​​of the radius of curvature R5 of the object side of the third lens 130 and the radius of curvature R6 of the image side becomes small, causing significant axial chromatic aberration. By satisfying conditional equation (25), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0080] Conditional equation (26) relates the refractive index n3 of the third lens 130 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of n3 / f is greater than or equal to the upper limit of 0.4, the positive refractive power of the third lens 130 becomes too large, causing significant axial chromatic aberration. If the value of n3 / f is less than or equal to the lower limit of 0.3, the positive refractive power of the third lens 130 becomes too small, causing the sagittal image plane to tilt. By satisfying conditional equation (26), the occurrence of axial chromatic aberration and the tilting of the sagittal image plane can be suppressed.

[0081] Conditional equation (27) relates the focal length f4 of the fourth lens 140 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f4 / f is greater than or equal to the upper limit of 3, the refractive power of the fourth lens 140 becomes too small, causing excessive spherical aberration at the peripheral image height. If the value of f4 / f is less than or equal to the lower limit of 2.8, the refractive power of the fourth lens 140 becomes too large, causing significant axial chromatic aberration. By satisfying conditional equation (27), the occurrence of spherical aberration and axial chromatic aberration at the peripheral image height can be suppressed.

[0082] Conditional equation (28) relates the radius of curvature R8 of the image side of the fourth lens 140 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R8 / f is greater than or equal to the upper limit of -3.4, the radius of curvature R8 of the image side of the fourth lens 140, which is in front of the aperture diaphragm 180, becomes smaller, and spherical aberration occurs on the underexposure side. When the value of R8 / f is less than or equal to the lower limit of -4.3, the radius of curvature R8 of the image side of the fourth lens 140, which has positive refractive power, becomes larger, and astigmatism occurs significantly. By satisfying conditional equation (28), the occurrence of spherical aberration and astigmatism can be suppressed.

[0083] Furthermore, the imaging lens 10 may satisfy the following conditions (29) to (31). 5.8 < ν³ / f < 5.9 (29) 14.4 < ν6 / f < 14.5 (30) 0.7 <D5 / f<0.9 (31) However, ν3 is the Abbe number of the third lens 130 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. ν6 is the Abbe number of the sixth lens 160 with respect to the d line. D5 is the on-axial thickness of the third lens 130.

[0084] Conditional equation (29) is an equation that relates the Abbe number ν3 of the third lens 130 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. When the value of ν3 / f is 5.9 or higher, the Abbe number ν3 of the third lens 130, which has positive refractive power in front of the aperture diaphragm 180, becomes large, and lateral chromatic aberration occurs on the underexposure side. When the value of ν3 / f is 5.8 or lower, which is the lower limit, the Abbe number ν3 of the third lens 130, which has positive refractive power in front of the aperture diaphragm 180, becomes small, and axial chromatic aberration occurs greatly. By satisfying conditional equation (29), the occurrence of lateral chromatic aberration and axial chromatic aberration can be suppressed.

[0085] Conditional equation (30) is an equation that relates the Abbe number ν6 of the sixth lens 160 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. When the value of ν6 / f is 14.5 or higher, the Abbe number ν6 of the sixth lens 160, which has positive refractive power behind the aperture diaphragm 180, becomes large, and lateral chromatic aberration occurs on the over-angle side. When the value of ν6 / f is 14.4 or lower, the Abbe number ν6 of the sixth lens 160, which has positive refractive power behind the aperture diaphragm 180, becomes small, and axial chromatic aberration occurs greatly. By satisfying conditional equation (30), the occurrence of lateral chromatic aberration and axial chromatic aberration can be suppressed.

[0086] Conditional equation (31) relates the axial thickness D5 of the third lens 130 to the focal length f of the imaging lens 10 with respect to the d line. When the value of D5 / f is greater than or equal to the upper limit of 0.9, the optical path length through the third lens 130 becomes longer, and spherical aberration becomes significantly underexposed. When the value of D5 / f is less than or equal to the lower limit of 0.7, the optical path length through the third lens 130 becomes shorter, and spherical aberration becomes significantly overexposed. By satisfying conditional equation (31), the occurrence of spherical aberration can be suppressed.

[0087] Furthermore, the object side of the second lens 120 of the imaging lens 10 is concave, and the imaging lens 10 may satisfy the following conditions (32) to (34). 0.5 <D12 / f<0.6 (32) 0 <D6 / f<0.1 (33) -1.8 <R3 / f<-1.5 (34) However, D12 is the on-axial thickness of the sixth lens 160. f is the focal length of the imaging lens 10 with respect to the d line. D6 is the on-axial distance from the image side of the third lens 130 to the object side of the fourth lens 140. R3 is the radius of curvature of the object side of the second lens 120.

[0088] By making the object side surface of the second lens 120 concave, it is possible to create a structure that contacts the edge surface of the image side surface of the first lens 110, which leads to a reduction in the number of parts and a reduction in part variation.

[0089] Conditional equation (32) relates the axial thickness D12 of the sixth lens 160 to the focal length f of the imaging lens 10 with respect to the d line. When the value of D12 / f is 0.6 or higher, the optical path length passing through the sixth lens 160, which has positive refractive power, becomes longer, and large axial chromatic aberration occurs. When the value of D12 / f is 0.5 or lower, which is lower than the lower limit, the optical path length passing through the sixth lens 160, which has positive refractive power, becomes shorter, and large spherical aberration occurs on the over-saturated side. By satisfying conditional equation (32), the occurrence of axial chromatic aberration and spherical aberration can be suppressed.

[0090] Conditional equation (33) relates the on-axial distance D6 from the image side of the third lens 130 to the object side of the fourth lens 140 to the focal length f of the imaging lens 10 with respect to the d line. When the value of D6 / f is greater than or equal to the upper limit of 0.1, the on-axial distance D6 from the image side of the third lens 130 to the object side of the fourth lens 140 widens, causing spherical aberration to be underexposed. When the value of D6 / f is less than or equal to the lower limit of 0, the on-axial distance D6 from the image side of the third lens 130 to the object side of the fourth lens 140 narrows, causing spherical aberration to be overexposed. By satisfying conditional equation (33), the occurrence of spherical aberration can be suppressed.

[0091] Conditional equation (34) relates the radius of curvature R3 of the object side of the second lens 120 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R3 / f is greater than or equal to the upper limit of -1.5, the radius of curvature R3 of the object side of the second lens 120, which has negative refractive power, becomes small, and large axial chromatic aberration occurs. When the value of R3 / f is less than or equal to the lower limit of -1.8, the radius of curvature R3 of the object side of the second lens 120, which has negative refractive power, becomes large, and large astigmatism occurs. By satisfying conditional equation (34), the occurrence of axial chromatic aberration and astigmatism can be suppressed.

[0092] Furthermore, the imaging lens 10 may satisfy the following conditions (35) and (36). 2.9 <f3 / f<3.4 (35) 2.1 <f5 / f<2.3 (36) However, f3 is the focal length of the third lens 130 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. f5 is the focal length of the fifth lens 150 with respect to the d line.

[0093] Conditional equation (35) is an equation that relates the focal length f3 of the third lens 130 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f3 / f is 3.4 or higher, the refractive power of the third lens 130 becomes too small, causing spherical aberration at the peripheral image height to be overexposed. If the value of f3 / f is 2.9 or lower, the refractive power of the third lens 130 becomes too large, causing spherical aberration at the peripheral image height to be underexposed. By satisfying conditional equation (35), the occurrence of spherical aberration at the peripheral image height can be suppressed.

[0094] Conditional equation (36) is an equation that relates the focal length f5 of the fifth lens 150 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f5 / f is 2.3 or higher, the refractive power of the fifth lens 150, which has a positive refractive power on the image side of the aperture diaphragm 180, becomes too small, resulting in significant astigmatism. If the value of f5 / f is 2.1 or lower, which is the lower limit, the refractive power of the fifth lens 150, which has a positive refractive power on the image side of the aperture diaphragm 180, becomes too large, resulting in underexposure of spherical aberration. By satisfying conditional equation (36), the occurrence of astigmatism and spherical aberration can be suppressed.

[0095] In one embodiment, the imaging lens 10 may satisfy the following conditions (37) to (39). -0.1 < (R7 + R8) / (R7 - R8) < 0.1 (37) 2.4 <R9 / f<2.6 (38) 1 <D10 / f<1.2 (39) However, R7 is the radius of curvature of the object side of the fourth lens 140. R8 is the radius of curvature of the image side of the fourth lens 140. R9 is the radius of curvature of the object side of the fifth lens 150. f is the focal length of the imaging lens 10 with respect to the d line. D10 is the on-axial thickness of the fifth lens 150.

[0096] Conditional equation (37) relates the radius of curvature R7 of the object side of the fourth lens 140 to the radius of curvature R8 of the image side of the fourth lens 140. When the value of (R7+R8) / (R7-R8) is greater than or equal to the upper limit of 0.1, the absolute value of the radius of curvature R7 of the object side of the fourth lens 140 becomes larger than the absolute value of the radius of curvature R8 of the image side, and spherical aberration becomes significantly overexposed. When the value of (R7+R8) / (R7-R8) is less than or equal to the lower limit of -0.1, the absolute value of the radius of curvature R8 of the image side of the fourth lens 140 becomes larger than the absolute value of the radius of curvature R7 of the object side, and astigmatism becomes significantly overexposed. By satisfying conditional equation (37), the occurrence of spherical aberration and astigmatism can be suppressed.

[0097] Conditional equation (38) relates the radius of curvature R9 of the object side surface of the fifth lens 150 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R9 / f is 2.6 or higher, the absolute value of the radius of curvature R9 of the object side surface, which is convex on the fifth lens 150, becomes large, and spherical aberration occurs on the over-spheric side. When the value of R9 / f is 2.4 or lower, the absolute value of the radius of curvature R9 of the object side surface, which is convex on the fifth lens 150, becomes small, and astigmatism occurs on the under-spheric side. By satisfying conditional equation (38), the occurrence of astigmatism can be suppressed.

[0098] Conditional equation (39) relates the axial thickness D10 of the fifth lens 150 to the focal length f of the imaging lens 10 with respect to the d line. When the value of D10 / f is 1.2 or higher, the optical path length of the fifth lens 150 becomes longer, causing spherical aberration to be overexposed. When the value of D10 / f is 1 or lower, the optical path length of the fifth lens 150 becomes shorter, causing spherical aberration to be underexposed. By satisfying conditional equation (39), the occurrence of spherical aberration can be suppressed.

[0099] Furthermore, each of the first lens 110, second lens 120, third lens 130, fourth lens 140, fifth lens 150, sixth lens 160, and seventh lens 170 of the imaging lens 10 is made of glass material, and the imaging lens 10 may satisfy the following conditions (40) and (41). 0.3 <n4 / f<0.4 (40) 0.1 <D14 / f<0.4 (41) However, n4 is the refractive index of the fourth lens 140 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. D14 is the on-axial thickness of the seventh lens 170.

[0100] Each of the first lens 110, second lens 120, third lens 130, fourth lens 140, fifth lens 150, sixth lens 160, and seventh lens 170 is made of glass material, which makes it possible to suppress yellowing due to ultraviolet light and / or changes in optical properties due to temperature changes.

[0101] Conditional equation (40) relates the refractive index n4 of the fourth lens 140 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. When the value of n4 / f is greater than or equal to the upper limit of 0.4, the refractive power of the fourth lens 140, which has positive refractive power, becomes large, causing significant chromatic aberration. When the value of n4 / f is less than or equal to the lower limit of 0.3, the refractive power of the fourth lens 140, which has positive refractive power, becomes small, causing excessive spherical aberration. By satisfying conditional equation (40), the occurrence of chromatic aberration and spherical aberration can be suppressed.

[0102] Conditional equation (41) relates the axial thickness D14 of the seventh lens 170 to the focal length f of the imaging lens 10 with respect to the d line. When the value of D14 / f is greater than or equal to the upper limit of 0.4, the optical path length of the seventh lens 170, which has negative refractive power, becomes longer, causing the meridional image plane to tilt to the overexposure side. When the value of D14 / f is less than or equal to the lower limit of 0.1, the optical path length of the seventh lens 170, which has negative refractive power, becomes shorter, causing significant axial chromatic aberration. By satisfying conditional equation (41), it is possible to suppress the meridional image plane from tilting to the overexposure side and to suppress the occurrence of axial chromatic aberration.

[0103] Furthermore, the image side and object side of the fifth lens 150 of the imaging lens 10 are formed as aspherical shapes, and the sixth lens 160 and the seventh lens 170 are formed as a cemented lens, and the imaging lens 10 may satisfy the following conditions (42) and (43). 1.1 <D89 / f<1.3 (42) 2 <R4 / f<2.2 (43) However, D89 is the on-axial distance from the image side of the fourth lens 140 to the object side of the fifth lens 150. D89 is the sum of the on-axial distance D8 from the image side of the fourth lens 140 to the aperture diaphragm 180 and the on-axial distance D9 from the aperture diaphragm 180 to the object side of the fifth lens 150. f is the focal length of the imaging lens 10 with respect to the d line. R4 is the radius of curvature of the image side of the second lens 120.

[0104] By making the object side and image side of the fifth lens 150, which is positioned on the image side of the aperture diaphragm 180 within the entire optical system, aspherical shapes are made easier to correct for aberrations.

[0105] By creating a cemented structure between the seventh lens 170 and the sixth lens 160, which are closest to the image plane 21, the correction of chromatic aberration and / or the construction of the integrated lens becomes easier.

[0106] Conditional equation (42) is an equation that relates the axial distance D89 from the image side of the fourth lens 140 to the object side of the fifth lens 150 to the focal length f of the imaging lens 10 with respect to the d line. If the value of D89 / f is 1.3 or higher, the distance between the front lens group and the rear lens group becomes too large, making it difficult to correct aberrations, especially those of the meridional ray, and causing large overexposure of astigmatism. If the value of D89 / f is 1.1 or lower, the distance between the front lens group and the rear lens group becomes too small, making it difficult to correct aberrations, especially those of the meridional ray, and causing large underexposure of astigmatism. By satisfying conditional equation (42), aberration correction of the meridional ray can be facilitated and the occurrence of astigmatism can be suppressed.

[0107] Conditional equation (43) relates the radius of curvature R4 of the image side of the second lens 120 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R4 / f is 2.2 or higher, the absolute value of the radius of curvature R4 of the image side of the second lens 120 becomes large, and axial chromatic aberration occurs in large quantities. When the value of R4 / f is 2 or lower, the absolute value of the radius of curvature R4 of the image side of the second lens 120 becomes small, and spherical aberration occurs in excess. By satisfying conditional equation (43), the occurrence of axial chromatic aberration and spherical aberration can be suppressed.

[0108] Furthermore, the imaging lens 10 may satisfy the following conditions (44) and (45). 2 <f6 / f<2.3 (44) -2 <f7 / f<-1.7 (45) However, f6 is the focal length of the sixth lens 160 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. f7 is the focal length of the seventh lens 170 with respect to the d line.

[0109] Conditional equation (44) is an equation that relates the focal length f6 of the sixth lens 160 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f6 / f is 2.3 or higher, the refractive power of the sixth lens 160, which has positive refractive power, becomes too small, causing the meridional image plane to tilt to the under-angle side. If the value of f6 / f is 2 or lower, which is the lower limit, the refractive power of the sixth lens 160, which has positive refractive power, becomes too large, causing significant axial chromatic aberration. By satisfying conditional equation (44), it is possible to suppress the tilt of the meridional image plane to the under-angle side and the occurrence of axial chromatic aberration.

[0110] Conditional equation (45) relates the focal length f7 of the seventh lens 170 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f7 / f is greater than or equal to the upper limit of -1.7, the refractive power of the seventh lens 170, which has the closest negative refractive power to the imaging surface, becomes too large, causing significant overexposure of chromatic aberration. If the value of f7 / f is less than or equal to the lower limit of -2, the refractive power of the seventh lens 170, which has the closest negative refractive power to the imaging surface, becomes too small, causing the meridional image plane to tilt to the overexposure side. By satisfying conditional equation (45), the occurrence of chromatic aberration and the tilting of the meridional image plane to the overexposure side can be suppressed.

[0111] In one embodiment, the image side and object side of the fifth lens 150 of the imaging lens 10 are formed as aspherical shapes, and the imaging lens 10 may satisfy the following conditions (46) to (48). 0.1<(R9+R10) / (R9-R10)<0.3 (46) 0.6 <D7 / f<0.8 (47) 0 <D11 / f<0.1 (48) However, R9 is the radius of curvature of the object side of the fifth lens 150. R10 is the radius of curvature of the image side of the fifth lens 150. D7 is the on-axial thickness of the fourth lens 140. f is the focal length of the imaging lens 10 with respect to the d line. D11 is the on-axial distance from the image side of the fifth lens 150 to the object side of the sixth lens 160.

[0112] By making the fifth lens 150, which is the first lens to receive light after the light ray passes through the longest air gap following the aperture 180 within the entire optical system, aspherical, effective aberration correction becomes possible.

[0113] Conditional equation (46) relates the radius of curvature R9 of the object side of the fifth lens 150 to the radius of curvature R10 of the image side. When the value of (R9+R10) / (R9-R10) is 0.3 or higher, the absolute difference between the radius of curvature R9 of the object side and the radius of curvature R10 of the image side of the fifth lens 150, which is the rear group convex lens closest to the aperture diaphragm 180, becomes large, and spherical aberration occurs to a large extent on the over-spherical side. When the value of (R9+R10) / (R9-R10) is 0.1 or lower, the absolute difference between the radius of curvature R9 of the object side and the radius of curvature R10 of the image side of the fifth lens 150 becomes small, and axial chromatic aberration occurs to a large extent. By satisfying conditional equation (46), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0114] Conditional equation (47) relates the axial thickness D7 of the fourth lens 140 to the focal length f of the imaging lens 10 with respect to the d line. When the value of D7 / f is greater than or equal to the upper limit of 0.8, the optical path length of the fourth lens 140, which has positive refractive power, becomes longer, and the meridional image plane tilts to the over-angle side. When the value of D7 / f is less than or equal to the lower limit of 0.6, the optical path length of the fourth lens 140, which has positive refractive power, becomes shorter, and the meridional image plane tilts to the under-angle side. By satisfying conditional equation (47), it is possible to suppress the meridional image plane from tilting to the over-angle or under-angle side.

[0115] Conditional equation (48) is an equation that relates the axial distance D11 from the image side of the fifth lens 150 to the object side of the sixth lens 160 to the focal length f of the imaging lens 10 with respect to the d line. If the value of D11 / f is greater than or equal to the upper limit of 0.1, the air gap between the cemented lens and the other lenses becomes longer, causing spherical aberration to occur on the underexposure side. If the value of D11 / f is less than or equal to the lower limit of 0, the air gap becomes shorter, making the mechanism design unfeasible from a tolerance standpoint. By satisfying conditional equation (48), the occurrence of spherical aberration can be suppressed, and the mechanism design can be made feasible.

[0116] Furthermore, the sixth lens 160 and the seventh lens 170 of the imaging lens 10 are formed as a cemented lens, the object side surface of the third lens 130 is convex, and the imaging lens 10 may satisfy the following condition (49). 4.1 <R5 / f<5.2 (49) However, R5 is the radius of curvature of the object side of the third lens 130. f is the focal length of the imaging lens 10 with respect to the d line.

[0117] By creating a cemented structure between the seventh lens 170 and the sixth lens 160, which are closest to the image plane 21, the imaging lens 10 becomes easier to correct for chromatic aberration and / or to incorporate into the lens frame.

[0118] By making the object side surface of the third lens 130, which is the next surface after the first lens 110 and the second lens 120 having negative refractive power, a convex surface is made, the imaging lens 10 can be easily widened in angle and also easily miniaturized in the radial direction.

[0119] Conditional equation (49) relates the radius of curvature R5 of the object side of the third lens 130 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R5 / f is greater than or equal to the upper limit of 5.2, the radius of curvature R5 of the object side of the third lens 130 becomes large, and spherical aberration occurs to the over-spherical side. When the value of R5 / f is less than or equal to the lower limit of 4.1, the radius of curvature R5 of the object side of the third lens 130 becomes small, and axial chromatic aberration occurs to a large extent. By satisfying conditional equation (49), the occurrence of spherical aberration and axial chromatic aberration can be suppressed.

[0120] Furthermore, the image surface of the seventh lens 170 of the imaging lens 10 is concave, and the imaging lens 10 may satisfy the following conditions (50) to (52). 0.3 <n5 / f<0.4 (50) -1.8 <R10 / f<-1.5 (51) 17 < ν5 / f < 18 (52) However, n5 is the refractive index of the fifth lens 150 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. R10 is the radius of curvature of the image side of the fifth lens 150. ν5 is the Abbe number of the fifth lens 150 with respect to the d line.

[0121] By making the image-side surface of the seventh lens 170, which is closest to the image plane 21, concave, a flat edge can be created, making it easier to assemble into the lens frame.

[0122] Conditional equation (50) relates the refractive index n5 of the fifth lens 150 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of n5 / f is 0.4 or higher, the refractive index n5 of the fifth lens 150, which has positive refractive power, becomes too high, causing significant axial chromatic aberration. If the value of n5 / f is 0.3 or lower, the refractive index n5 of the fifth lens 150, which has positive refractive power, becomes too low, causing excessive spherical aberration. By satisfying conditional equation (50), the occurrence of axial chromatic aberration and spherical aberration can be suppressed.

[0123] Conditional equation (51) relates the radius of curvature R10 of the image side surface of the fifth lens 150 to the focal length f of the imaging lens 10 with respect to the d line. When the value of R10 / f is greater than or equal to the upper limit of -1.5, the radius of curvature R10 of the convex surface of the image side surface of the fifth lens 150 becomes smaller, and astigmatism occurs on the under-biased side. When the value of R10 / f is less than or equal to the lower limit of -1.8, the radius of curvature R10 of the convex surface of the image side surface of the fifth lens 150 becomes larger, and spherical aberration occurs significantly on the over-biased side. By satisfying conditional equation (51), the occurrence of astigmatism and spherical aberration can be suppressed.

[0124] Conditional equation (52) is an equation that relates the Abbe number ν5 of the fifth lens 150 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of ν5 / f is 18 or higher, which is the upper limit, the Abbe number ν5 of the fifth lens 150, which has positive refractive power, becomes too large, causing a large over-aspect ratio of chromatic aberration. If the value of ν5 / f is 17 or lower, which is the lower limit, the Abbe number ν5 of the fifth lens 150, which has positive refractive power, becomes too small, causing a large over-aspect ratio of chromatic aberration. By satisfying conditional equation (52), the occurrence of both over-aspect ratio and over-aspect ratio of chromatic aberration can be suppressed.

[0125] Furthermore, the imaging lens 10 may satisfy the following conditions (53) and (54). -2 <f7 / f<-1.7 (53) -1.4 <f2 / f<-1.2 (54) However, f7 is the focal length of the seventh lens 170 with respect to the d line. f is the focal length of the imaging lens 10 with respect to the d line. f2 is the focal length of the second lens 120 with respect to the d line.

[0126] Conditional equation (53) relates the focal length f7 of the seventh lens 170 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f7 / f is greater than or equal to the upper limit of -1.7, the refractive power of the seventh lens 170, which has the closest negative refractive power to the imaging surface, becomes too large, causing significant overexposure of chromatic aberration. If the value of f7 / f is less than or equal to the lower limit of -2, the refractive power of the seventh lens 170, which has the closest negative refractive power to the imaging surface, becomes too small, causing the meridional image plane to tilt to the overexposure side. By satisfying conditional equation (53), the occurrence of chromatic aberration and the tilting of the meridional image plane to the overexposure side can be suppressed.

[0127] Conditional equation (54) is an equation that relates the focal length f2 of the second lens 120 with respect to the d line to the focal length f of the imaging lens 10 with respect to the d line. If the value of f2 / f is greater than or equal to the upper limit of -1.2, the refractive power of the second lens 120 becomes too large, causing the meridional image plane to tilt to the over-angle side. If the value of f2 / f is less than or equal to the lower limit of -1.4, the refractive power of the second lens 120 becomes too small, causing field curvature to occur to the under-angle side. By satisfying conditional equation (54), it is possible to suppress the meridional image plane from tilting to the over-angle side and the field curvature from occurring to the under-angle side. [Examples]

[0128] Next, the lens configuration of the embodiments relating to the imaging lens 10 of this disclosure will be mainly described. More specifically, Embodiments 1 to 8 with specific numerical values ​​for the imaging lens 10 will be shown. Embodiments 1 to 8 have the characteristics of the imaging lens 10 described above in terms of the positive or negative refractive power of each lens, the surface shape, and the parameters shown in conditional equations (1) to (54).

[0129] In Examples 1 to 8, the focal length of the imaging lens 10, the F-number on the optical axis Ax of the imaging lens 10, and the total length Da are as shown in Table 1. In the data for each example in Table 1, the values ​​derived from the lens specifications, including the focal length, are also values ​​relative to the d line unless otherwise specified.

[0130] [Table 1]

[0131] In Examples 1 to 8, the parameter values ​​included in each of the conditional expressions (1) to (12) are as shown in Table 2 below.

[0132] [Table 2]

[0133] In Examples 1 to 8, the parameter values ​​included in each of the conditional expressions (13) to (24) are as shown in Table 3.

[0134] [Table 3]

[0135] In Examples 1 to 8, the parameter values ​​included in each of the conditional expressions (25) to (36) are as shown in Table 4.

[0136] [Table 4]

[0137] In Examples 1 to 8, the parameter values ​​included in each of the conditional expressions (37) to (45) are as shown in Table 5.

[0138] [Table 5]

[0139] In Examples 1 to 8, the parameter values ​​included in each of the conditional expressions (46) to (54) are as shown in Table 6.

[0140] [Table 6]

[0141] In the basic lens data for each embodiment, the number i (where i is a natural number from 1 to 17) in the lens specifications is the surface number assigned sequentially from the object side to each surface of all lenses included in the imaging lens 10, the aperture diaphragm 180, and the flat plate 190. Si shown in Figure 1 represents the i-th surface. Di is the distance on the optical axis Ax between the i-th surface Si and the (i+1)th surface Si+1. Rj (where j is a natural number from 1 to 16) is the radius of curvature of each surface of each lens and the flat plate 190. The radius of curvature of the object side of the k-th lens (where k is a natural number from 1 to 7) is Rj (j=2k-1), and the radius of curvature of the image side is Rj (j=2k). The radii of curvature of the object side and image side of the flat plate 190 are represented by R15 and R16, respectively. Nd is the refractive index for the d line. νd is the Abbe number for the d line. The interplanar spacing Di is shown only in Figure 1 of Example 1, and is omitted from the drawings of the other examples.

[0142] In all the following specifications, the units of length, such as the radius of curvature Rj and interplanar spacing Di, are millimeters (mm) unless otherwise specified, and their notation in each table is omitted. In each table, "E" indicates exponential expression (power of 10). The configuration of the imaging lens 10 is not limited to the configuration in the following embodiments, and equivalent optical performance can be obtained in both proportional magnification and proportional reduction.

[0143] In the following examples, the shape of the aspherical surface of the lens is expressed by the following equation (55). Equation (55) is the aspherical equation.

[0144]

number

[0145] In equation (55), each value is considered positive in the direction from the object to the image. k is the conicity coefficient, A is the 4th-order aspheric coefficient, B is the 6th-order aspheric coefficient, C is the 8th-order aspheric coefficient, and D is the 10th-order aspheric coefficient. h is the height of the ray, c is the reciprocal of the central radius of curvature, and Z is the depth from the tangent plane to the vertex of the surface. The aspheric data in each of the following examples shows the aspheric coefficients, etc., when the shape of the aspheric surface on the lens surface marked with "*" in the basic lens data is expressed in equation (55).

[0146] (Example 1) Figure 1 is a lens configuration diagram of the imaging lens 10 according to Embodiment 1 of the present disclosure. Figure 1 shows the lens configuration of the imaging lens 10 according to Embodiment 1 in an optical cross-section. As shown in Figure 1, in the imaging lens 10 of Embodiment 1, the refractive power and shape of the first lens 110 to the seventh lens 170 are as described above.

[0147] In Figure 1, D1 corresponds to the thickness of the first lens 110 on the optical axis Ax. D3 corresponds to the thickness of the second lens 120 on the optical axis Ax. D5 corresponds to the thickness of the third lens 130 on the optical axis Ax. D7 corresponds to the thickness of the fourth lens 140 on the optical axis Ax. D10 corresponds to the thickness of the fifth lens 150 on the optical axis Ax. D12 corresponds to the thickness of the sixth lens 160 on the optical axis Ax. D14 corresponds to the thickness of the seventh lens 170 on the optical axis Ax. D16 corresponds to the thickness of the flat plate 190 on the optical axis Ax. The above explanation regarding the interplanar spacing Di also applies to the following other embodiments.

[0148] Table 7 shows the basic lens data, including the specifications of the imaging lens 10 according to Example 1. In Table 7, for the aspherical surfaces S10 and S11 indicated by "*", the values ​​of curvature radii R9 and R10 represent the paraxial radius of curvature.

[0149] [Table 7]

[0150] Table 8 shows the aspherical data, including the aspherical coefficient, of the imaging lens 10 according to Example 1. The aspherical data shown in Table 8 are the data for surfaces S10 and S11 of the fifth lens 150, respectively.

[0151] [Table 8]

[0152] Figures 2A, 2B, and 2C are graphs showing the various aberrations of the imaging lens 10 in Figure 1.

[0153] Figure 2A is a graph showing the astigmatism of the imaging lens 10 in Figure 1. In Figure 2A, the vertical axis represents the incident height on the entrance pupil normalized to a pupil diameter of 1, and the horizontal axis represents the shift in the image formation position. Each line in the graph represents the astigmatism (mm) for light of each wavelength shown on the right of the graph. "Sagittal" refers to the image plane value in the sagittal direction, and "Tangential" refers to the image plane value in the vertical (hereinafter referred to as tangential) direction.

[0154] Figure 2B is a graph showing the distortion aberration of the imaging lens 10 in Figure 1. In Figure 2B, the vertical axis represents the incident height on the entrance pupil normalized to a pupil diameter of 1, and the horizontal axis represents the shift in the image formation position. Each line in the graph represents the distortion aberration (%) for light of each wavelength shown on the right of the graph.

[0155] Figure 2C is a graph showing the spherical aberration of the imaging lens 10 in Figure 1. In Figure 2C, the vertical axis represents the incident height on the entrance pupil normalized to a pupil diameter of 1, and the horizontal axis represents the shift in the image formation position. Each line in the graph represents the spherical aberration (mm) for light of each wavelength shown on the right of the graph.

[0156] As shown in Figures 2A, 2B, and 2C, according to Example 1, astigmatism, distortion, and spherical aberration are well corrected, and an imaging lens 10 with excellent imaging performance is obtained.

[0157] The above explanation regarding the aberration diagrams also applies to the aberration diagrams shown in other embodiments, so further explanation will be omitted below.

[0158] (Example 2) Figure 3 is a lens configuration diagram of the imaging lens 10 according to Embodiment 2 of this disclosure. Figure 3 shows the lens configuration of the imaging lens 10 according to Embodiment 2 in an optical cross-section. As shown in Figure 3, in the imaging lens 10 of Embodiment 2, the refractive power and shape of the first lens 110 to the seventh lens 170 are as described above.

[0159] Table 9 shows the basic lens data, including the specifications of the imaging lens 10 according to Example 2. In Table 9, for the aspherical surfaces S10 and S11 indicated by "*", the values ​​of curvature radii R9 and R10 represent the paraxial radius of curvature.

[0160] [Table 9]

[0161] Table 10 shows the aspherical data, including the aspherical coefficient, of the imaging lens 10 according to Example 2. The aspherical data shown in Table 10 are the data for surfaces S10 and S11 of the fifth lens 150, respectively.

[0162] [Table 10]

[0163] Figures 4A, 4B, and 4C are aberration diagrams of the imaging lens 10 in Figure 3. Figure 4A is a graph showing the astigmatism of the imaging lens 10 in Figure 3. Figure 4B is a graph showing the distortion of the imaging lens 10 in Figure 3. Figure 4C is a graph showing the spherical aberration of the imaging lens 10 in Figure 3. As shown in Figures 4A, 4B, and 4C, according to Embodiment 2, astigmatism, distortion, and spherical aberration are well corrected, and an imaging lens 10 with excellent imaging performance is obtained.

[0164] (Example 3) Figure 5 is a lens configuration diagram of the imaging lens 10 according to Embodiment 3 of this disclosure. Figure 5 shows the lens configuration of the imaging lens 10 according to Embodiment 3 in an optical cross-section. As shown in Figure 5, in the imaging lens 10 of Embodiment 3, the refractive power and shape of the first lens 110 to the seventh lens 170 are as described above.

[0165] Table 11 shows the basic lens data, including the specifications of the imaging lens 10 according to Example 3. In Table 11, for the aspherical surfaces S10 and S11 indicated by "*", the values ​​of curvature radii R9 and R10 represent the paraxial curvature radius.

[0166] [Table 11]

[0167] Table 12 shows the aspherical data, including the aspherical coefficient, of the imaging lens 10 according to Example 3. The aspherical data shown in Table 12 are the data for surfaces S10 and S11 of the fifth lens 150, respectively.

[0168] [Table 12]

[0169] Figures 6A, 6B, and 6C are aberration diagrams of the imaging lens 10 in Figure 5. Figure 6A is a graph showing the astigmatism of the imaging lens 10 in Figure 5. Figure 6B is a graph showing the distortion of the imaging lens 10 in Figure 5. Figure 6C is a graph showing the spherical aberration of the imaging lens 10 in Figure 5. As shown in Figures 6A, 6B, and 6C, according to Example 3, astigmatism, distortion, and spherical aberration are well corrected, and an imaging lens 10 with excellent imaging performance is obtained.

[0170] (Example 4) Figure 7 is a lens configuration diagram of the imaging lens 10 according to Embodiment 4 of this disclosure. Figure 7 shows the lens configuration of the imaging lens 10 according to Embodiment 4 in an optical cross-section. As shown in Figure 7, in the imaging lens 10 of Embodiment 4, the refractive power and shape of the first lens 110 to the seventh lens 170 are as described above.

[0171] Table 13 shows the basic lens data, including the specifications of the imaging lens 10 according to Example 4. In Table 13, for the aspherical surfaces S10 and S11 indicated by "*", the values ​​of curvature radii R9 and R10 represent the paraxial radius of curvature.

[0172] [Table 13]

[0173] Table 14 shows the aspherical data, including the aspherical coefficient, of the imaging lens 10 according to Example 4. The aspherical data shown in Table 14 are the data for surfaces S10 and S11 of the fifth lens 150, respectively.

[0174] [Table 14]

[0175] Figures 8A, 8B, and 8C are aberration diagrams of the imaging lens 10 in Figure 7. Figure 8A is a graph showing the astigmatism of the imaging lens 10 in Figure 7. Figure 8B is a graph showing the distortion of the imaging lens 10 in Figure 7. Figure 8C is a graph showing the spherical aberration of the imaging lens 10 in Figure 7. As shown in Figures 8A, 8B, and 8C, according to Example 4, astigmatism, distortion, and spherical aberration are well corrected, and an imaging lens 10 with excellent imaging performance is obtained.

[0176] (Example 5) FIG. 9 is a lens configuration diagram of the imaging lens 10 according to Embodiment 5 of the present disclosure. FIG. 9 shows the lens configuration of the imaging lens 10 according to Embodiment 5 in an optical cross-section. As shown in FIG. 9, in the imaging lens 10 of Embodiment 5, the refractive powers and shapes of the first lens 110 to the seventh lens 170 are as described above.

[0177] Table 15 shows the basic lens data including the specifications of the imaging lens 10 according to Embodiment 5. In Table 15, for the aspherical surfaces S10 and S11 indicated by "※", the values of the radii of curvature R9 and R10 represent the paraxial radii of curvature.

[0178]

Table 15

[0179] Table 16 shows the aspherical data including the aspherical coefficients of the imaging lens 10 according to Embodiment 5. The aspherical data shown in Table 16 are the data for each of the surfaces S10 and S11 of the fifth lens 150.

[0180]

Table 16

[0181] FIGS. 10A, 10B, and 10C are aberration diagrams of the imaging lens 10 of FIG. 9. FIG. 10A is a graph showing the astigmatism of the imaging lens 10 of FIG. 9. FIG. 10B is a graph showing the distortion of the imaging lens 10 of FIG. 9. FIG. 10C is a graph showing the spherical aberration of the imaging lens 10 of FIG. 9. As shown in FIGS. 10A, 10B, and 10C, according to Embodiment 5, an imaging lens 10 with good correction of astigmatism, distortion, spherical aberration, etc. and excellent imaging performance can be obtained.

[0182] (Embodiment 6) Figure 11 is a lens configuration diagram of the imaging lens 10 according to Embodiment 6 of this disclosure. Figure 11 shows the lens configuration of the imaging lens 10 according to Embodiment 6 in an optical cross-section. As shown in Figure 11, in the imaging lens 10 of Embodiment 6, the refractive power and shape of the first lens 110 to the seventh lens 170 are as described above.

[0183] Table 17 shows the basic lens data, including the specifications of the imaging lens 10 according to Example 6. In Table 17, for the aspherical surfaces S10 and S11 indicated by "*", the values ​​of curvature radii R9 and R10 represent the paraxial radius of curvature.

[0184] [Table 17]

[0185] Table 18 shows the aspherical data, including the aspherical coefficient, of the imaging lens 10 according to Example 2. The aspherical data shown in Table 18 are the data for surfaces S10 and S11 of the fifth lens 150, respectively.

[0186] [Table 18]

[0187] Figures 12A, 12B, and 12C are aberration diagrams of the imaging lens 10 in Figure 11. Figure 12A is a graph showing the astigmatism of the imaging lens 10 in Figure 11. Figure 12B is a graph showing the distortion of the imaging lens 10 in Figure 11. Figure 12C is a graph showing the spherical aberration of the imaging lens 10 in Figure 11. As shown in Figures 12A, 12B, and 12C, according to Example 6, astigmatism, distortion, and spherical aberration are well corrected, and an imaging lens 10 with excellent imaging performance is obtained.

[0188] (Example 7) FIG. 13 is a lens configuration diagram of the imaging lens 10 according to Embodiment 7 of the present disclosure. FIG. 13 shows the lens configuration of the imaging lens 10 according to Embodiment 7 in an optical cross section. As shown in FIG. 13, in the imaging lens 10 of Embodiment 7, the refractive powers and shapes of the first lens 110 to the seventh lens 170 are as described above.

[0189] Table 19 shows the basic lens data including the specifications of the imaging lens 10 according to Embodiment 7. In Table 19, for the aspherical surfaces S10 and S11 indicated by "※", the values of the curvature radii R9 and R10 represent the paraxial curvature radii.

[0190]

Table 19

[0191] Table 20 shows the aspherical data including the aspherical coefficients of the imaging lens 10 according to Embodiment 7. The aspherical data shown in Table 20 are the data for each of the surfaces S10 and S11 of the fifth lens 150.

[0192] ]>

Table 20

[0193] FIG. 14A, FIG. 14B, and FIG. 14C are aberration diagrams of the imaging lens 10 of FIG. 13. FIG. 14A is a graph showing the astigmatism of the imaging lens 10 of FIG. 13. FIG. 14B is a graph showing the distortion of the imaging lens 10 of FIG. 13. FIG. 14C is a graph showing the spherical aberration of the imaging lens 10 of FIG. 1-. As shown in FIG. 14A, FIG. 14B, and FIG. 14C, according to Embodiment 7, an imaging lens 10 with good correction of astigmatism, distortion, spherical aberration, etc. and excellent imaging performance can be obtained.

[0194] (Embodiment 8) Figure 15 is a lens configuration diagram of the imaging lens 10 according to Embodiment 8 of this disclosure. Figure 15 shows the lens configuration of the imaging lens 10 according to Embodiment 8 in an optical cross-section. As shown in Figure 15, in the imaging lens 10 of Embodiment 8, the refractive power and shape of the first lens 110 to the seventh lens 170 are as described above.

[0195] Table 21 shows the basic lens data, including the specifications of the imaging lens 10 according to Example 8. In Table 21, for the aspherical surfaces S10 and S11 indicated by "*", the values ​​of curvature radii R9 and R10 represent the paraxial radius of curvature.

[0196] [Table 21]

[0197] Table 22 shows the aspherical data, including the aspherical coefficient, of the imaging lens 10 according to Example 8. The aspherical data shown in Table 22 are the data for surfaces S10 and S11 of the fifth lens 150, respectively.

[0198] [Table 22]

[0199] Figures 16A, 16B, and 16C are aberration diagrams of the imaging lens 10 in Figure 15. Figure 16A is a graph showing the astigmatism of the imaging lens 10 in Figure 15. Figure 16B is a graph showing the distortion of the imaging lens 10 in Figure 15. Figure 16C is a graph showing the spherical aberration of the imaging lens 10 in Figure 15. As shown in Figures 16A, 16B, and 16C, according to Example 8, astigmatism, distortion, and spherical aberration are well corrected, and an imaging lens 10 with excellent imaging performance is obtained.

[0200] As described above, the imaging lens 10 and imaging device 1 according to the embodiments of this disclosure enable high optical performance with a seven-element configuration. As a result, it is possible to realize an imaging lens 10 and imaging device 1 with high optical performance that can be mounted on cameras, including surveillance cameras and in-vehicle cameras. The imaging lens 10 and imaging device 1 according to one embodiment of this disclosure may be mounted on a moving body. The moving body may include, for example, automobiles, industrial vehicles, railway vehicles, residential vehicles, and fixed-wing aircraft that travel on runways. Automobiles may include, for example, passenger cars, trucks, buses, motorcycles, and trolleybuses. Industrial vehicles may include, for example, industrial vehicles for agriculture and construction. Industrial vehicles may include, for example, forklifts and golf carts. Industrial vehicles for agriculture may include, for example, tractors, cultivators, transplanters, binders, combines, and lawnmowers. Industrial vehicles for construction may include, for example, bulldozers, scrapers, excavators, cranes, dump trucks, and road rollers. The moving body may include those that are moved by human power.

[0201] It will be apparent to those skilled in the art that this disclosure can be implemented in other predetermined forms besides the embodiments described above without deviating from its spirit or essential features. Therefore, the prior description is illustrative and not limiting. The scope of the disclosure is defined not by the prior description but by the added claims. Any modifications within their equivalent scope are included therein.

[0202] For example, the shape, size, arrangement, orientation, and number of each component described above are not limited to those shown in the above description and drawings. The shape, size, arrangement, orientation, and number of each component may be configured arbitrarily as long as they can achieve their function.

[0203] Although an imaging lens 10 according to one embodiment has been described, this disclosure is not limited to the imaging lens 10 of each embodiment described above, and various modifications are possible without departing from the spirit of the invention. For example, the specifications of the imaging lens 10 of each embodiment are illustrative, and various parameters can be changed within the scope of this disclosure. [Explanation of Symbols]

[0204] 1. Imaging device 10 imaging lenses 110 First Lens 120 Second lens 130 Third Lens 140 Fourth Lens 150 Fifth Lens 160 6th lens 170 7th lens 180 aperture diaphragm 190 flat plate 20 Image sensors 21 Image plane Ax optical axis Di inter-plane spacing Da Total Length Rj radius of curvature Si surface

Claims

1. An imaging lens comprising a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, wherein the front lens group consists of four lenses, including two or fewer lenses having negative refractive power, and the rear lens group consists of three lenses, including one or fewer lenses having negative refractive power.

2. The imaging lens according to claim 1, wherein the front lens group is composed of a first lens having negative refractive power, a second lens having negative refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power, arranged in order from the object side, and the rear lens group is composed of a fifth lens having positive refractive power, a sixth lens having positive refractive power, and a seventh lens having negative refractive power, arranged in order from the object side.

3. If R1 is the radius of curvature of the object side of the first lens, R2 is the radius of curvature of the image side of the first lens, R11 is the radius of curvature of the object side of the sixth lens, R12 is the radius of curvature of the image side of the sixth lens, D2 is the on-axial distance from the image side of the first lens to the object side of the second lens, f is the focal length of the imaging lens with respect to the d line, and D1 is the on-axial thickness of the first lens, then the conditional equation is: 1.9<(R1+R2) / (R1-R2)<2.1 (1) 0.2<(R11+R12) / (R11-R12)<0.4 (2) 0.4<D2 / f<0.6 (3) 0.1<D1 / f<0.3 (4) An imaging lens according to claim 2 that satisfies the following conditions.

4. If R6 is the radius of curvature of the image surface of the third lens, then the conditional equation is: 3.2<R1 / f<3.4 (5) -5<R6 / f<-3.7 (6) 3.2<R11 / f<4.1 (7) An imaging lens according to claim 3 that satisfies the following conditions.

5. The image surface of the third lens is convex, If ν1 is the Abbe number of the first lens with respect to the d line, n1 is the refractive index of the first lens with respect to the d line, and n7 is the refractive index of the seventh lens with respect to the d line, then the conditional equation is: 12<ν1 / f<12.3 (8) 0.3<n1 / f<0.4 (9) 0.3<n7 / f<0.4 (10) An imaging lens according to claim 4 that satisfies the following conditions.

6. If the focal length of the first lens with respect to the d line is f1 and the focal length of the second lens with respect to the d line is f2, then the conditional equation is, -2.5<f1 / f<-2.2 (11) -1.4<f2 / f<-1.2 (12) The imaging lens according to claim 5, which satisfies the condition.

7. The object side surface of the fourth lens is convex, If the focal length of the imaging lens with respect to the d-line is f, the on-axial distance from the image side of the first lens to the object side of the second lens is D2, the radius of curvature of the object side of the second lens is R3, and the radius of curvature of the image side of the second lens is R4, then the conditional equation is, 3.3<R7 / f<4.3 (13) 0<D2 / f<0.2 (14) -0.2<(R3+R4) / (R3-R4)<0 (15) An imaging lens according to claim 2 that satisfies the following conditions.

8. If the radius of curvature of the object side of the seventh lens is R13, the radius of curvature of the image side of the seventh lens is R14, the on-axial thickness of the second lens is D3, and the radius of curvature of the image side of the first lens is R2, then the conditional equation is: -0.7<(R13+R14) / (R13-R14)<-0.5 (16) 0.2<D3 / f<0.3 (17) 1<R2 / f<1.2 (18) An imaging lens according to claim 7 that satisfies the following conditions.

9. If R12 is the radius of curvature of the image side of the sixth lens, R13 is the radius of curvature of the object side of the seventh lens, ν2 is the Abbe number of the second lens with respect to the d line, and n2 is the refractive index of the second lens with respect to the d line, then the conditional equation is: -2<R12 / f<-1.9 (19) -2<R13 / f<-1.9 (20) 6.8<ν2 / f<6.9 (21) 0.3<n2 / f<0.4 (22) An imaging lens according to claim 8 that satisfies the following conditions.

10. If the focal length of the fourth lens with respect to the d line is f4 and the focal length of the fifth lens with respect to the d line is f5, then the conditional equation is, 2.8<f4 / f<3 (23) 2.1<f5 / f<2.3 (24) The imaging lens according to claim 9, which satisfies the condition.

11. If R5 is the radius of curvature of the object side of the third lens, R6 is the radius of curvature of the image side of the third lens, n3 is the refractive index of the third lens with respect to the d line, f is the focal length of the imaging lens with respect to the d line, f4 is the focal length of the fourth lens with respect to the d line, and R8 is the radius of curvature of the image side of the fourth lens, then the conditional equation is: 0<(R5+R6) / (R5-R6)<0.2 (25) 0.3<n3 / f<0.4 (26) 2.8<f4 / f<3 (27) -4.3<R8 / f<-3.4 (28) An imaging lens according to claim 2 that satisfies the following conditions.

12. If the Abbe number of the third lens with respect to the d line is ν3, the Abbe number of the sixth lens with respect to the d line is ν6, and the on-axial thickness of the third lens is D5, then the conditional equation is: 5.8<ν3 / f<5.9 (29) 14.4<ν6 / f<14.5 (30) 0.7<D5 / f<0.9 (31) The imaging lens according to claim 11, which satisfies the condition.

13. The object side surface of the second lens is concave, If the on-axial thickness of the sixth lens is D12, the on-axial distance from the image side of the third lens to the object side of the fourth lens is D6, and the radius of curvature of the object side of the second lens is R3, then the conditional equation is, 0.5<D12 / f<0.6 (32) 0<D6 / f<0.1 (33) -1.8<R3 / f<-1.5 (34) The imaging lens according to claim 12, which satisfies the condition.

14. If the focal length of the third lens with respect to the d line is f3 and the focal length of the fifth lens with respect to the d line is f5, then the conditional equation is, 2.9<f3 / f<3.4 (35) 2.1<f5 / f<2.3 (36) The imaging lens according to claim 13, which satisfies the condition.

15. If R7 is the radius of curvature of the object side of the fourth lens, R8 is the radius of curvature of the image side of the fourth lens, R9 is the radius of curvature of the object side of the fifth lens, f is the focal length of the imaging lens with respect to the d line, and D10 is the on-axial thickness of the fifth lens, then the conditional equation is: -0.1<(R7+R8) / (R7-R8)<0.1 (37) 2.4<R9 / f<2.6 (38) 1<D10 / f<1.2 (39) An imaging lens according to claim 2 that satisfies the following conditions.

16. Each of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens is made of glass material. If the refractive index of the fourth lens with respect to the d line is n4 and the on-axial thickness of the seventh lens is D14, then the conditional equation is: 0.3<n4 / f<0.4 (40) 0.1<D14 / f<0.4 (41) The imaging lens according to claim 15, which satisfies the condition.

17. The image side and object side of the fifth lens are formed as aspherical shapes. The sixth lens and the seventh lens are formed as a cemented lens. If D89 is the on-axial distance from the image side of the fourth lens to the object side of the fifth lens, and R4 is the radius of curvature of the image side of the second lens, then the conditional equation is: 1.1<D89 / f<1.3 (42) 2<R4 / f<2.2 (43) An imaging lens according to claim 16 that satisfies the following conditions.

18. If the focal length of the sixth lens with respect to the d line is f6 and the focal length of the seventh lens with respect to the d line is f7, then the conditional equation is, 2<f6 / f<2.3 (44) -2<f7 / f<-1.7 (45) An imaging lens according to claim 17 that satisfies the following conditions.

19. The image side and object side of the fifth lens are formed as aspherical shapes. If R9 is the radius of curvature of the object side of the fifth lens, R10 is the radius of curvature of the image side of the fifth lens, D7 is the on-axial thickness of the fourth lens, f is the focal length of the imaging lens with respect to the d line, and D11 is the on-axial distance from the image side of the fifth lens to the object side of the sixth lens, then the conditional equation is: 0.1<(R9+R10) / (R9-R10)<0.3 (46) 0.6<D7 / f<0.8 (47) 0<D11 / f<0.1 (48) An imaging lens according to claim 2 that satisfies the following conditions.

20. The sixth lens and the seventh lens are formed as a cemented lens. The object side surface of the third lens is convex, If the radius of curvature of the object side of the third lens is R5, then the conditional equation is: 4.1<R5 / f<5.2 (49) An imaging lens according to claim 19 that satisfies the following conditions.

21. The image surface of the seventh lens is concave. If the refractive index of the fifth lens with respect to the d line is n5, the radius of curvature of the image surface of the fifth lens is R10, and the Abbe number of the fifth lens with respect to the d line is ν5, then the conditional equation is: 0.3<n5 / f<0.4 (50) -1.8<R10 / f<-1.5 (51) 17<ν5 / f<18 (52) The imaging lens according to claim 20, which satisfies the condition.

22. If the focal length of the seventh lens with respect to the d line is f7 and the focal length of the second lens with respect to the d line is f2, then the conditional equation is, -2<f7 / f<-1.7 (53) -1.4<f2 / f<-1.2 (54) The imaging lens according to claim 21, which satisfies the condition.

23. An imaging lens comprising a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, wherein the front lens group consists of four lenses including two or fewer lenses having negative refractive power, and the rear lens group consists of three lenses including one or fewer lenses having negative refractive power, An image sensor that converts the optical image formed through the aforementioned imaging lens into an electrical signal. An imaging device equipped with the following features.

24. An imaging lens comprising a front lens group, an aperture diaphragm, and a rear lens group arranged in order from the object side, wherein the front lens group consists of four lenses including two or fewer lenses having negative refractive power, and the rear lens group consists of three lenses including one or fewer lenses having negative refractive power, An image sensor that converts the optical image formed through the aforementioned imaging lens into an electrical signal. A mobile body having an imaging device equipped with a [specific component].

Images