wide-angle lens

Abstract

A wide-angle lens is provided, which can be applied to large imaging elements and has good chromatic aberration correction. The wide-angle lens (1) includes a front group (10), an aperture (30) and a rear group (20) from the object side (La) to the image side (Lb). The front group (10) includes a first group (110) with negative optical power and a second group (120) with positive optical power from the object side (La) to the image side (Lb). The second group (120) includes a second first lens (121), a second second lens (122) and a second third lens (123) from the object side (La) to the image side (Lb). If the Abbe number of the d-line of the second second lens (122) is set to ν4 and the Abbe number of the d-line of the second third lens (123) is set to ν5, then the following conditions (1) and (2) are satisfied: ν4 < 30.00……(1); 44.00 < ν5……(2).

Description

Technical Field

[0001] This disclosure relates to a wide-angle lens. Background Technology

[0002] Previously, lens structures for achieving high resolution in wide-angle lenses have been proposed. For example, Patent Document 1 discloses a wide-angle lens with the following lens structure: arranged sequentially from the object side: a first lens and a second lens having negative optical power; a third lens having positive optical power; an aperture; a fourth lens and a fifth lens having positive optical power; a sixth lens having negative optical power; and a seventh lens having positive optical power.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 7547679 Summary of the Invention

[0006] In recent years, the size of camera sensors has been increasing. However, when the wide-angle lens described in Patent Document 1 is applied to large camera sensors, it is difficult to obtain the required optical performance. In particular, the wide-angle lens structure described in Patent Document 1 is difficult to correct for chromatic aberration.

[0007] This disclosure provides a wide-angle lens that can be applied to large camera elements and has good chromatic aberration correction.

[0008] The wide-angle lens of this disclosure comprises, from the object side to the image side, a front group, an aperture group, and a rear group. The front group comprises, from the object side to the image side, a first group with negative optical power and a second group with positive optical power. The second group comprises, from the object side to the image side, a second group of first lenses, a second group of second lenses, and a second group of third lenses. When the Abbe number of the d-line of the second group of second lenses is set to ν4, and the Abbe number of the d-line of the second group of third lenses is set to ν5, the following conditions (1) and (2) are satisfied: ν4<30.00……(1) 44.00<ν5……(2) According to this disclosure, chromatic aberration can be well corrected, thus wide-angle lenses can be applied to large camera elements. Attached Figure Description

[0009] Figure 1 This is an explanatory diagram of the wide-angle lens according to Embodiment 1 of this disclosure.

[0010] Figure 2 It is shown Figure 1 The graph shows the data for a wide-angle lens.

[0011] Figure 3 It is shown Figure 1The diagram shows the spherical aberration of a wide-angle lens.

[0012] Figure 4 It is shown Figure 1 The diagram shows the chromatic aberration of a wide-angle lens.

[0013] Figure 5 It is shown Figure 1 The image shown shows astigmatism and distortion.

[0014] Figure 6 It is shown Figure 1 The diagram shows the lateral aberrations.

[0015] Figure 7 This is an explanatory diagram of the wide-angle lens according to Embodiment 2 of this disclosure.

[0016] Figure 8 It is shown Figure 7 The graph shows the data for a wide-angle lens.

[0017] Figure 9 It is shown Figure 7 The diagram shows the spherical aberration of a wide-angle lens.

[0018] Figure 10 It is shown Figure 7 The diagram shows the chromatic aberration of a wide-angle lens.

[0019] Figure 11 It is shown Figure 7 The image shown shows astigmatism and distortion.

[0020] Figure 12 It is shown Figure 7 The diagram shows the lateral aberrations.

[0021] Figure 13 This is an explanatory diagram of the wide-angle lens according to Embodiment 3 of this disclosure.

[0022] Figure 14 It is shown Figure 13 The graph shows the data for a wide-angle lens.

[0023] Figure 15 It is shown Figure 13 The diagram shows the spherical aberration of a wide-angle lens.

[0024] Figure 16 It is shown Figure 13 The diagram shows the chromatic aberration of a wide-angle lens.

[0025] Figure 17 It is shown Figure 13 The image shown shows astigmatism and distortion.

[0026] Figure 18 It is shown Figure 13The diagram shows the lateral aberrations.

[0027] Figure 19 This is an explanatory diagram of the wide-angle lens according to Embodiment 4 of this disclosure.

[0028] Figure 20 It is shown Figure 19 The graph shows the data for a wide-angle lens.

[0029] Figure 21 It is shown Figure 19 The diagram shows the spherical aberration of a wide-angle lens.

[0030] Figure 22 It is shown Figure 19 The diagram shows the chromatic aberration of a wide-angle lens.

[0031] Figure 23 It is shown Figure 19 The image shown shows astigmatism and distortion.

[0032] Figure 24 It is shown Figure 19 The diagram shows the lateral aberrations.

[0033] Figure 25 This is an explanatory diagram of the wide-angle lens according to Embodiment 5 of this disclosure.

[0034] Figure 26 It is shown Figure 25 The graph shows the data for a wide-angle lens.

[0035] Figure 27 It is shown Figure 25 The diagram shows the spherical aberration of a wide-angle lens.

[0036] Figure 28 It is shown Figure 25 The diagram shows the chromatic aberration of a wide-angle lens.

[0037] Figure 29 It is shown Figure 25 The image shown shows astigmatism and distortion.

[0038] Figure 30 It is shown Figure 25 The diagram shows the lateral aberrations. Detailed Implementation

[0039] The wide-angle lens 1 will now be described with reference to the accompanying drawings. The wide-angle lens 1 is used, for example, in sensor devices for automobiles, etc.

[0040] (Implementation Method 1)

[0041] Figure 1 This is an explanatory diagram of the wide-angle lens 1 according to Embodiment 1 of this disclosure. (As shown...) Figure 1As shown, the wide-angle lens 1 of this embodiment includes a front group 10, an aperture 30, and a rear group 20 sequentially from the object side La to the image side Lb.

[0042] The front group 10, from the object side La to the image side Lb, comprises a first group 110 with negative optical power and a second group 120 with positive optical power. The first group 110, from the object side La to the image side Lb, consists of a first group of first lenses 111 and a first group of second lenses 112. The second group 120, from the object side La to the image side Lb, consists of a second group of first lenses 121, a second group of second lenses 122, and a second group of third lenses 123.

[0043] The rear group 20 consists of the first lens 201, the second lens 202, the third lens 203, and the fourth lens 205 in sequence from the object side La to the image side Lb.

[0044] Additionally, on the image side Lb of the fourth lens 205 in the rear group, a light-transmitting cover 40 and an imaging element 50 are arranged sequentially from the object side La to the image side Lb. The imaging element 50 is disposed on the imaging surface of the image side Lb of the wide-angle lens 1.

[0045] The first lens 111 in the first group is, for example, a lens made of glass. The first lens 111 in the first group has negative optical power. In the first lens 111, the object-side lens surface 1111 (La) is convex, and the image-side lens surface 1112 (Lb) is concave. The second lens 112 in the first group is, for example, a lens made of resin. The second lens 112 in the first group has negative optical power. In the second lens 112, the object-side lens surface 1121 (La) is convex, and the image-side lens surface 1122 (Lb) is concave. Both surfaces of the second lens 112 in the first group are aspherical.

[0046] The second group of first lenses 121 is, for example, a lens made of resin. The second group of first lenses 121 has negative optical power. In the second group of first lenses 121, the lens surface 1211 on the object side La is concave, and the lens surface 1212 on the image side Lb is convex. Both surfaces of the second group of first lenses 121 are aspherical. The second group of second lenses 122 is, for example, a lens made of resin. The second group of second lenses 122 has positive optical power. In the second group of second lenses 122, the lens surface 1221 on the object side La is convex, and the lens surface 1222 on the image side Lb is convex. Both surfaces of the second group of second lenses 122 are aspherical. The second group of third lenses 123 is, for example, a lens made of resin. The second group of third lenses 123 has positive optical power. In the second group of third lenses 123, the lens surface 1231 on the object side La is concave, and the lens surface 1232 on the image side Lb is convex. Both surfaces of the second group of third lenses 123 are aspherical.

[0047] The first lens 201 in the rear group is, for example, a lens made of glass. The first lens 201 in the rear group has positive power. In the first lens 201 in the rear group, the lens surface 2011 on the object side La is convex, and the lens surface 2012 on the image side Lb is convex. The second lens 202 in the rear group is, for example, a lens made of resin. The second lens 202 in the rear group has negative power. In the second lens 202 in the rear group, the lens surface 2021 on the object side La is concave, and the lens surface 2022 on the image side Lb is concave. Both surfaces of the second lens 202 in the rear group are aspherical. The third lens 203 in the rear group is, for example, a lens made of resin. The third lens 203 in the rear group has positive power. In the third lens 203 in the rear group, the lens surface 2031 on the object side La is convex, and the lens surface 2032 on the image side Lb is convex. Both surfaces of the third lens 203 in the rear group are aspherical.

[0048] Here, the second lens 202 and the third lens 203 of the rear group are a combined lens 204, wherein the lens surface 2022 of the image side Lb of the second lens 202 and the lens surface 2031 of the object side La of the third lens 203 are joined by, for example, an adhesive (not shown). According to this structure, the rear group 20 includes the combined lens 204, and therefore, chromatic aberration can be appropriately corrected.

[0049] The fourth lens 205 in the rear group is, for example, a lens made of resin. The fourth lens 205 in the rear group has positive optical power. In the fourth lens 205 in the rear group, the lens surface 2051 on the object side La is convex, and the lens surface 2052 on the image side Lb is concave. Both surfaces of the fourth lens 205 in the rear group are aspherical.

[0050] (Lens structure)

[0051] Figure 2 This is a diagram showing the data of the wide-angle lens 1 in Embodiment 1. Figure 2 The values ​​shown have been rounded to the nearest whole number.

[0052] Figure 2 The following data are shown. Here, the total length of the entire lens system is the distance along the optical axis L from the object-side lens surface 1111 of the first lens 111 in the first group to the imaging surface of the imaging element 50. The total length from the first lens 111 in the first group to the fourth lens 205 in the subsequent group is the distance along the optical axis L from the object-side lens surface 1111 of the first lens 111 in the first group to the image-side lens surface 2052 of the fourth lens 205 in the subsequent group.

[0053] The focal distance f0 of the entire lens system (Effective Focal Length)

[0054] The total length d0 (Total Track) of the entire lens system

[0055] Image Space F-number of the entire lens system

[0056] Maximum field of view (MPF)

[0057] Pupil Diameter

[0058] The total length between the first lens in the first group and the fourth lens in the subsequent group (L1R1-L9R2 Track)

[0059] Figure 2 Lens data for each lens is also shown below. Surface numbers are marked with an asterisk (...). The surface of the object is aspherical. The units for radius of curvature, thickness, and focal distance are millimeters.

[0060] Here, lens surface 1111 forms the first surface. Lens surface 1112 forms the second surface. Lens surface 1121 forms the third surface. Lens surface 1122 forms the fourth surface. Lens surface 1211 forms the fifth surface. Lens surface 1212 forms the sixth surface. Lens surface 1221 forms the seventh surface. Lens surface 1222 forms the eighth surface. Lens surface 1231 forms the ninth surface. Lens surface 1232 forms the tenth surface. Aperture 30 forms the eleventh surface. Lens surface 2011 forms the twelfth surface. Lens surface 2012 forms the thirteenth surface. Lens surface 2021 forms the fourteenth surface. Lens surfaces 2022 and 2031 form the fifteenth surface. Lens surface 2032 forms the sixteenth surface. Lens surface 2051 forms the seventeenth surface. Lens surface 2052 forms the eighteenth surface. The object-side surface 401 of the cover 40 (La) forms the nineteenth surface, and the image-side surface 402 of the cover (Lb) forms the twentieth surface.

[0061] Radius of curvature

[0062] Thickness

[0063] Refractive index (Nd)

[0064] Abbe number (νd) of the d-line

[0065] Focal distance (f)

[0066] Lens radius (sd)

[0067] Figure 2 The aspherical coefficients representing the aspherical shape for each surface number are also shown.

[0068] In the wide-angle lens 1 of embodiment 1, when the Abbe number of the second lens 122 of the second group is ν4 and the Abbe number of the third lens 123 of the second group is ν5, the following conditions (1) and (2) are satisfied.

[0069] ν4<30.00……(1)

[0070] 44.00<ν5……(2)

[0071] In condition (2), it is more preferable to satisfy the following condition (2a).

[0072] 50.00<ν5……(2a)

[0073] In this embodiment, ν4=21.62 ν5 = 56.13. Therefore, ν4 = 21.62, satisfying condition (1). And, ν5 = 56.13, therefore, satisfying conditions (2) and (2a).

[0074] In the wide-angle lens 1 of embodiment 1, when the focal distance of the entire lens system is f0 and the combined focal distance of the second lens 122 and the third lens 123 of the second group is f45, the following condition (3) is satisfied.

[0075] 2.000<f45 / f0<3.500……(3)

[0076] In this embodiment, f0 = 2.872 mm f45 = 7.714 mm. Therefore, f45 / f0 = 2.686, which satisfies condition (3).

[0077] In the wide-angle lens 1 of Embodiment 1, when the focal distance of the entire lens system is f0 and the combined focal distance of the second group of first lens 121, the second group of second lens 122 and the second group of second lens 123 is f345, the following condition (4) is satisfied.

[0078] 2.000<f345 / f0<6.000……(4)

[0079] In this embodiment, f0 = 2.872 mm f345 = 13.653 mm. Therefore, f345 / f0 = 4.754, which satisfies condition (4).

[0080] In the wide-angle lens 1 of embodiment 1, when the radius of curvature of the lens surface of the image side Lb of the first group of second lenses 112 is R22 and the radius of curvature of the lens surface of the object side La of the second group of first lenses 121 is R31, the following condition (5) is satisfied.

[0081] -1.000<R22 / R31<-0.500……(5)

[0082] In this embodiment, R22 = 3.823 mm R31 = -5.846 mm. Therefore, R22 / R31 = -0.654, which satisfies condition (5).

[0083] In the wide-angle lens 1 of embodiment 1, when the focal distance of the entire lens system is f0, the radius of curvature of the lens surface of the image side Lb of the first group of second lenses 112 is R22 and the radius of curvature of the lens surface of the object side La of the second group of first lenses 121 is R31, the following conditions (6) and (7) are satisfied.

[0084] 1.100<R22 / f0<3.000……(6)

[0085] -3.000<R31 / f0<-1.100……(7)

[0086] In this embodiment, f0 = 2.872 mm R22 = 3.823 mm R31 = -5.846 mm. Therefore, R22 / f0 = 1.331, satisfying condition (6). And, R31 / f0 = -2.036, satisfying condition (7).

[0087] In the wide-angle lens 1 of Embodiment 1, when the refractive index of the d-line of the fourth lens 205 of the rear group is N9, the following condition (8) is satisfied.

[0088] 1.500 < N9……(8)

[0089] In this embodiment, N9 = 1.663. Therefore, N9 = 1.663 satisfies condition (8).

[0090] In the wide-angle lens 1 of Embodiment 1, when the radius of curvature of the lens surface on the object side La of the rear first lens 201 is R61 and the radius of curvature of the lens surface on the image side Lb of the rear first lens 201 is R62, the following condition (9) is satisfied.

[0091] |R61|>|R62| ……(9)

[0092] In this embodiment, R61 = 8.512 mm R62 = -6.524 mm. Therefore, condition (9) is satisfied.

[0093] In the wide-angle lens 1 of embodiment 1, when the Abbe number of the d-line of the second lens 202 of the rear group is ν7 and the Abbe number of the d-line of the third lens 203 of the rear group is ν8, the following conditional expressions (10) and (11) are satisfied.

[0094] ν7<30.00……(10)

[0095] 50.00<ν8……(11)

[0096] In this embodiment, ν7=21.62 ν8 = 56.13. Therefore, ν7 = 21.62, satisfying condition (10). And, ν8 = 56.13, satisfying condition (11).

[0097] In the wide-angle lens 1 of embodiment 1, when the distance between the object and the image of the entire lens system is d0 and the focal distance of the entire lens system is f0, the following condition (12) is satisfied.

[0098] 6.000<d0 / f0<12.000……(12)

[0099] In this embodiment, d0 = 27.450 mm f0 = 2.872 mm. Therefore, d0 / f0 = 9.558, which satisfies condition (12).

[0100] In the wide-angle lens 1 of embodiment 1, when the maximum half field of view is ω, the following condition (13) is satisfied.

[0101] 75°<ω<110°......(13)

[0102] In this embodiment, ω = 94°. Therefore, condition (13) is satisfied.

[0103] (Function and effect)

[0104] The wide-angle lens 1 of this embodiment satisfies conditions (1) and (2), so it can correct chromatic aberration well, and thus the wide-angle lens 1 can also be applied to large imaging elements 50.

[0105] The wide-angle lens 1 of this embodiment satisfies condition (3), thus preventing an increase in the total length of the entire lens system and preventing the occurrence of various aberrations. If the value of condition (3) is lower than the lower limit, the combined optical power of the second lens 122 and the third lens 123 becomes too strong, making it difficult to suppress the occurrence of various aberrations. If the value of condition (3) exceeds the upper limit, the combined optical power of the second lens 122 and the third lens 123 becomes too weak, and the total length of the entire lens system is prone to increase.

[0106] The wide-angle lens 1 of this embodiment satisfies condition (4), thus preventing an increase in the total length of the entire lens system and preventing the occurrence of various aberrations. If the value of condition (4) is lower than the lower limit, the combined optical power of the second group of first lens 121, second group of second lens 122, and second group of third lens 123 becomes too strong, making it difficult to suppress the occurrence of various aberrations. If the value of condition (4) exceeds the upper limit, the combined optical power of the second group of first lens 121, second group of second lens 122, and second group of third lens 123 becomes too weak, and the total length of the entire lens system is prone to increase.

[0107] In this embodiment, the object-side lens surface of the second lens 122 in the second group is a convex curved surface with at least one inflection point, and the image-side lens surface is also a convex curved surface, thereby allowing for appropriate correction of astigmatism and image plane curvature.

[0108] In this embodiment, the second lens 122 and / or the third lens 123 of the second group are lenses made of resin, thus reducing manufacturing costs.

[0109] The wide-angle lens 1 of this embodiment satisfies condition (5), thus preventing an increase in the total length and outer diameter of the entire lens system, and also preventing the occurrence of various aberrations. If the value of condition (5) is lower than the lower limit, the combined optical power of the first group of second lenses 112 and the second group of first lenses 121 becomes too weak, and the total length and outer diameter of the entire lens system are prone to increase. If the value of condition (5) exceeds the upper limit, the combined optical power of the first group of second lenses 112 and the second group of first lenses 121 becomes too strong, making it difficult to suppress the occurrence of various aberrations.

[0110] The wide-angle lens 1 of this embodiment satisfies conditions (6) and (7), thus preventing an increase in the total length and outer diameter of the entire lens system, and also preventing the occurrence of various aberrations. If the value of condition (6) is lower than the lower limit, the radius of curvature R22 of the image-side lens surface of the first group of second lenses 112 becomes too small. That is, the optical power of the image-side lens surface of the first group of second lenses 112 becomes too strong. This makes it difficult to suppress the occurrence of various aberrations. If the value of condition (6) exceeds the upper limit, the radius of curvature R22 of the image-side lens surface of the first group of second lenses 112 becomes too large. That is, the optical power of the image-side lens surface of the first group of second lenses 112 becomes too weak. Therefore, the total length and outer diameter of the entire lens system tend to increase.

[0111] Furthermore, if the value of condition (7) is below the lower limit, the radius of curvature R31 of the object-side lens surface of the second group of first lenses 121 becomes too large. That is, the optical power of the object-side lens surface of the second group of first lenses 121 becomes too weak. Therefore, the total length of the entire lens system and the outer diameter of the lens tend to increase. If the value of condition (7) exceeds the upper limit, the radius of curvature R31 of the object-side lens surface of the second group of first lenses 121 becomes too small. That is, the optical power of the object-side lens surface of the second group of first lenses 121 becomes too strong. This makes it difficult to suppress the occurrence of various aberrations.

[0112] The wide-angle lens 1 of this embodiment satisfies condition (8), therefore the rear fourth lens 205 has a high refractive index. In addition, since the rear fourth lens 205 has a convex lens surface and a concave lens surface with an inflection point, it is easy to perform image height correction, astigmatism correction and image plane curvature correction relative to the field of view.

[0113] The wide-angle lens 1 of this embodiment satisfies condition (9), and therefore various aberrations can be appropriately corrected.

[0114] The wide-angle lens 1 of this embodiment satisfies conditions (10) and (11), and therefore chromatic aberration can be appropriately corrected.

[0115] In the wide-angle lens 1 of this embodiment, the fourth lens 205 of the rear group is a single lens with positive optical power, so that the chief ray angle (hereinafter also referred to as CRA (Chief Ray Angle)) and image height characteristics can be easily adjusted.

[0116] The wide-angle lens 1 of this embodiment satisfies condition (12), in other words, the ratio of the object-image distance d0 of the entire lens system to the focal distance f0 of the entire lens system exceeds the lower limit, thereby appropriately correcting spherical aberration and distortion. Furthermore, since the ratio of the object-image distance d0 of the entire lens system to the focal distance f0 of the entire lens system is less than the upper limit, it prevents the lens diameter from becoming too large and avoids an increase in the total length of the entire lens system. Therefore, miniaturization of the wide-angle lens can be achieved.

[0117] The wide-angle lens 1 in this embodiment satisfies condition (13), in other words, the maximum half-field-of-view exceeds the lower limit, thereby obtaining a sufficiently wide field of view. Furthermore, since the maximum half-field-of-view is less than the upper limit, it prevents a reduction in the amount of information per field of view. If the maximum half-field-of-view exceeds the upper limit, the amount of information per field of view will decrease, leading to a drop in resolution.

[0118] Figure 3 It is shown Figure 1 The diagram shows the spherical aberration of the wide-angle lens 1. Figure 4 It is shown Figure 1 The graph of magnification chromatic aberration for the wide-angle lens 1 shown illustrates the magnification chromatic aberration at the maximum half field of view (93.6241 degrees). Figure 5 It is shown Figure 1 The diagram shows the astigmatism and distortion of the wide-angle lens 1. Figure 6 It is shown Figure 1 The diagram showing the lateral aberration of the wide-angle lens 1 illustrates the lateral aberration in the tangential (Y direction) and radial (X direction).

[0119] exist Figures 3 to 6 In the diagram, the aberrations at wavelengths of 486nm, 546nm, and 656nm are labeled with B, G, and R and shown. For Figure 5 The astigmatism shown is labeled S for radial characteristics and T for tangential characteristics. Additionally, Figure 5 The distortion shown indicates the proportion of image variation in the central and peripheral parts of the image. The smaller the absolute value of the distortion, the higher the lens accuracy.

[0120] like Figures 3 to 6 As shown, in the wide-angle lens 1 of this embodiment, spherical aberration, magnification chromatic aberration, astigmatism (distortion) and lateral aberration are corrected to appropriate levels.

[0121] (Implementation Method 2)

[0122] Figure 7 This is an explanatory diagram of the wide-angle lens 1 according to Embodiment 2 of this disclosure. Figure 7 As shown, the wide-angle lens 1 of this embodiment includes a front group 10, an aperture 30, and a rear group 20 sequentially from the object side La to the image side Lb.

[0123] The front group 10, from the object side La to the image side Lb, comprises a first group 110 with negative optical power and a second group 120 with positive optical power. The first group 110, from the object side La to the image side Lb, is composed of a first group of first lenses 111 and a first group of second lenses 112. The second group 120, from the object side La to the image side Lb, is composed of a second group of first lenses 121, a second group of second lenses 122, and a second group of third lenses 123.

[0124] The rear group 20 is composed of a first lens 201, a second lens 202, a third lens 203, and a fourth lens 205, arranged sequentially from the object side La to the image side Lb. In addition, on the image side Lb of the fourth lens 205, a light-transmitting cover 40 and an imaging element 50 are arranged sequentially from the object side La to the image side Lb.

[0125] The first lens 111 in the first group is, for example, a lens made of glass. The first lens 111 in the first group has negative optical power. In the first lens 111, the object-side lens surface 1111 (La) is convex, and the image-side lens surface 1112 (Lb) is concave. The second lens 112 in the first group is, for example, a lens made of resin. The second lens 112 in the first group has negative optical power. In the second lens 112, the object-side lens surface 1121 (La) is convex, and the image-side lens surface 1122 (Lb) is concave. Both surfaces of the second lens 112 in the first group are aspherical.

[0126] The second group of first lenses 121 is, for example, a lens made of resin. The second group of first lenses 121 has negative optical power. In the second group of first lenses 121, the lens surface 1211 on the object side La is concave, and the lens surface 1212 on the image side Lb is convex. Both surfaces of the second group of first lenses 121 are aspherical. The second group of second lenses 122 is, for example, a lens made of resin. The second group of second lenses 122 has positive optical power. In the second group of second lenses 122, the lens surface 1221 on the object side La is convex, and the lens surface 1222 on the image side Lb is convex. Both surfaces of the second group of second lenses 122 are aspherical. The second group of third lenses 123 is, for example, a lens made of resin. The second group of third lenses 123 has positive optical power. In the second group of third lenses 123, the lens surface 1231 on the object side La is concave, and the lens surface 1232 on the image side Lb is convex. Both surfaces of the second group of third lenses 123 are aspherical.

[0127] The first lens 201 in the rear group is, for example, a lens made of glass. The first lens 201 in the rear group has positive power. In the first lens 201 in the rear group, the lens surface 2011 on the object side La is convex, and the lens surface 2012 on the image side Lb is convex. The second lens 202 in the rear group is, for example, a lens made of resin. The second lens 202 in the rear group has negative power. In the second lens 202 in the rear group, the lens surface 2021 on the object side La is concave, and the lens surface 2022 on the image side Lb is concave. Both surfaces of the second lens 202 in the rear group are aspherical. The third lens 203 in the rear group is, for example, a lens made of resin. The third lens 203 in the rear group has positive power. In the third lens 203 in the rear group, the lens surface 2031 on the object side La is convex, and the lens surface 2032 on the image side Lb is convex. Both surfaces of the third lens 203 in the rear group are aspherical.

[0128] Here, the second lens 202 and the third lens 203 of the rear group are a combined lens 204, wherein the lens surface 2022 of the image side Lb of the second lens 202 and the lens surface 2031 of the object side La of the third lens 203 are joined by, for example, an adhesive (not shown). According to this structure, the rear group 20 includes the combined lens 204, thereby allowing for appropriate correction of chromatic aberration.

[0129] The fourth lens 205 in the rear group is, for example, a lens made of resin. The fourth lens 205 in the rear group has positive optical power. In the fourth lens 205 in the rear group, the lens surface 2051 on the object side La is convex, and the lens surface 2052 on the image side Lb is concave. Both surfaces of the fourth lens 205 in the rear group are aspherical.

[0130] (Lens structure)

[0131] Figure 8 This is a diagram showing the data of the wide-angle lens 1 in Embodiment 2. Figure 8 The values ​​shown have been rounded to the nearest whole number. The wide-angle lens 1 of this embodiment satisfies the conditional expressions (1) to (13) described in Embodiment 1.

[0132] In this embodiment, ν4=21.62 ν5 = 56.13. Therefore, ν4 = 21.62, satisfying condition (1). Also, ν5 = 56.13, satisfying conditions (2) and (2a).

[0133] In this embodiment, f0 = 2.872 mm f45 = 7.703 mm. Therefore, f45 / f0 = 2.682, which satisfies condition (3).

[0134] In this embodiment, f0 = 2.872 mm f345 = 13.172 mm. Therefore, f345 / f0 = 4.586, which satisfies condition (4).

[0135] In this embodiment, R22 = 3.787 mm R31 = -6.029 mm. Therefore, R22 / R31 = -0.628, which satisfies condition (5).

[0136] In this embodiment, f0 = 2.872 mm R22 = 3.787 mm R31 = -6.029 mm. Therefore, R22 / f0 = 1.318, satisfying condition (6). And, R31 / f0 = -2.099, satisfying condition (7).

[0137] In this embodiment, N9 = 1.663. Therefore, N9 = 1.663 satisfies condition (8).

[0138] In this embodiment, R61 = 8.654 mm R62 = -6.643 mm. Therefore, condition (9) is satisfied.

[0139] In this embodiment, ν7=21.62 ν8 = 56.13. Therefore, ν7 = 21.62, satisfying condition (10). And, ν8 = 56.13, satisfying condition (11).

[0140] In this embodiment, d0 = 27.449 mm f0 = 2.872 mm. Therefore, d0 / f0 = 9.558, which satisfies condition (12).

[0141] In this embodiment, ω = 94°. Therefore, condition (13) is satisfied.

[0142] (Function and effect)

[0143] The wide-angle lens 1 in Embodiment 2 is the same as that in Embodiment 1, satisfying conditions (1) to (13), and thus can achieve the same effect as in Embodiment 1.

[0144] Figure 9 It is shown Figure 7 The diagram shows the spherical aberration of the wide-angle lens 1. Figure 10 It is shown Figure 7 The diagram shows the chromatic aberration of the wide-angle lens 1. Figure 11 It is shown Figure 7 The diagram shows the astigmatism and distortion of the wide-angle lens 1. Figure 12 It is shown Figure 7 The diagram shows the lateral aberration of the wide-angle lens 1.

[0145] like Figures 9 to 12 As shown, in the wide-angle lens 1 of this embodiment, spherical aberration, magnification chromatic aberration, astigmatism (distortion) and lateral aberration are corrected to appropriate levels.

[0146] (Implementation Method 3)

[0147] Figure 13 This is an explanatory diagram of the wide-angle lens 1 according to Embodiment 3 of this disclosure. Figure 13 As shown, the wide-angle lens 1 of this embodiment includes a front group 10, an aperture 30, and a rear group 20 sequentially from the object side La to the image side Lb.

[0148] The front group 10, from the object side La to the image side Lb, comprises a first group 110 with negative optical power and a second group 120 with positive optical power. The first group 110, from the object side La to the image side Lb, is composed of a first group of first lenses 111 and a first group of second lenses 112. The second group 120, from the object side La to the image side Lb, is composed of a second group of first lenses 121, a second group of second lenses 122, and a second group of third lenses 123.

[0149] The rear group 20 is composed of a first lens 201, a second lens 202, a third lens 203, and a fourth lens 205, arranged sequentially from the object side La to the image side Lb. In addition, on the image side Lb of the fourth lens 205, a light-transmitting cover 40 and an imaging element 50 are arranged sequentially from the object side La to the image side Lb.

[0150] The first lens 111 in the first group is, for example, a lens made of glass. The first lens 111 in the first group has negative optical power. In the first lens 111, the object-side lens surface 1111 (La) is convex, and the image-side lens surface 1112 (Lb) is concave. The second lens 112 in the first group is, for example, a lens made of resin. The second lens 112 in the first group has negative optical power. In the second lens 112, the object-side lens surface 1121 (La) is convex, and the image-side lens surface 1122 (Lb) is concave. Both surfaces of the second lens 112 in the first group are aspherical.

[0151] The second group of first lenses 121 is, for example, a lens made of resin. The second group of first lenses 121 has negative optical power. In the second group of first lenses 121, the lens surface 1211 on the object side La is concave, and the lens surface 1212 on the image side Lb is convex. Both surfaces of the second group of first lenses 121 are aspherical. The second group of second lenses 122 is, for example, a lens made of resin. The second group of second lenses 122 has positive optical power. In the second group of second lenses 122, the lens surface 1221 on the object side La is convex. The lens surface 1222 on the image side Lb is convex. Both surfaces of the second group of second lenses 122 are aspherical. The second group of third lenses 123 is, for example, a lens made of resin. The second group of third lenses 123 has positive optical power. In the second group of third lenses 123, the lens surface 1231 on the object side La is concave, and the lens surface 1232 on the image side Lb is convex. Both surfaces of the second group of third lenses 123 are aspherical.

[0152] The first lens 201 in the rear group is, for example, a lens made of glass. The first lens 201 in the rear group has positive power. In the first lens 201 in the rear group, the lens surface 2011 on the object side La is convex, and the lens surface 2012 on the image side Lb is convex. The second lens 202 in the rear group is, for example, a lens made of resin. The second lens 202 in the rear group has negative power. In the second lens 202 in the rear group, the lens surface 2021 on the object side La is concave, and the lens surface 2022 on the image side Lb is concave. Both surfaces of the second lens 202 in the rear group are aspherical. The third lens 203 in the rear group is, for example, a lens made of resin. The third lens 203 in the rear group has positive power. In the third lens 203 in the rear group, the lens surface 2031 on the object side La is convex, and the lens surface 2032 on the image side Lb is convex. Both surfaces of the third lens 203 in the rear group are aspherical.

[0153] Here, the second lens 202 and the third lens 203 of the rear group are a combined lens 204, wherein the lens surface 2022 of the image side Lb of the second lens 202 and the lens surface 2031 of the object side La of the third lens 203 are joined by, for example, an adhesive (not shown). According to this structure, the rear group 20 includes the combined lens 204, thereby allowing for appropriate correction of chromatic aberration.

[0154] The fourth lens 205 in the rear group is, for example, a lens made of resin. The fourth lens 205 in the rear group has positive optical power. In the fourth lens 205 in the rear group, the lens surface 2051 on the object side La is convex, and the lens surface 2052 on the image side Lb is concave. Both surfaces of the fourth lens 205 in the rear group are aspherical.

[0155] (Lens structure)

[0156] Figure 14 This is a diagram showing the data of the wide-angle lens 1 in Embodiment 3. Figure 14 The values ​​shown have been rounded to the nearest whole number. The wide-angle lens 1 of this embodiment satisfies the conditional expressions (1) to (13) described in Embodiment 1.

[0157] In this embodiment, ν4=21.62 ν5 = 56.13. Therefore, ν4 = 21.62, satisfying condition (1). Also, ν5 = 56.13, satisfying conditions (2) and (2a).

[0158] In this embodiment, f0 = 2.870 mm f45 = 7.656 mm. Therefore, f45 / f0 = 2.667, which satisfies condition (3).

[0159] In this embodiment, f0 = 2.870 mm f345 = 13.505 mm. Therefore, f345 / f0 = 4.705, which satisfies condition (4).

[0160] In this embodiment, R22 = 3.816 mm R31 = -5.812 mm. Therefore, R22 / R31 = -0.657, which satisfies condition (5).

[0161] In this embodiment, f0 = 2.870 mm R22 = 3.816 mm R31 = -5.812 mm. Therefore, R22 / f0 = 1.329, satisfying condition (6). And, R31 / f0 = -2.025, satisfying condition (7).

[0162] In this embodiment, N9 = 1.663. Therefore, N9 = 1.663 satisfies condition (8).

[0163] In this embodiment, R61 = 8.510 mm R62 = -6.524 mm. Therefore, condition (9) is satisfied.

[0164] In this embodiment, ν7=21.62 ν8 = 56.13. Therefore, ν7 = 21.62, satisfying condition (10). And, ν8 = 56.13, satisfying condition (11).

[0165] In this embodiment, d0 = 27.450 mm f0 = 2.870 mm. Therefore, d0 / f0 = 9.563, which satisfies condition (12).

[0166] In this embodiment, ω = 94°. Therefore, condition (13) is satisfied.

[0167] (Function and effect)

[0168] The wide-angle lens 1 in Embodiment 3 is the same as that in Embodiment 1, satisfying conditions (1) to (13), and thus can achieve the same effect as in Embodiment 1.

[0169] Figure 15 It is shown Figure 13 The diagram shows the spherical aberration of the wide-angle lens 1. Figure 16 It is shown Figure 13 The diagram shows the chromatic aberration of the wide-angle lens 1. Figure 17 It is shown Figure 13 The diagram shows the astigmatism and distortion of the wide-angle lens 1. Figure 18 It is shown Figure 13 The diagram shows the lateral aberration of the wide-angle lens 1.

[0170] like Figures 15 to 18 As shown, in the wide-angle lens 1 of this embodiment, spherical aberration, magnification chromatic aberration, astigmatism (distortion) and lateral aberration are corrected to appropriate levels.

[0171] (Implementation Method 4)

[0172] Figure 19 This is an explanatory diagram of the wide-angle lens 1 according to Embodiment 4 of this disclosure. Figure 19 As shown, the wide-angle lens 1 of this embodiment includes a front group 10, an aperture 30, and a rear group 20 sequentially from the object side La to the image side Lb.

[0173] The front group 10, from the object side La to the image side Lb, comprises a first group 110 with negative optical power and a second group 120 with positive optical power. The first group 110, from the object side La to the image side Lb, is composed of a first group of first lenses 111 and a first group of second lenses 112. The second group 120, from the object side La to the image side Lb, is composed of a second group of first lenses 121, a second group of second lenses 122, and a second group of third lenses 123.

[0174] The rear group 20 is composed of a first lens 201, a second lens 202, a third lens 203, and a fourth lens 205, arranged sequentially from the object side La to the image side Lb. In addition, on the image side Lb of the fourth lens 205, a light-transmitting cover 40 and an imaging element 50 are arranged sequentially from the object side La to the image side Lb.

[0175] The first lens 111 in the first group is, for example, a lens made of glass. The first lens 111 in the first group has negative optical power. In the first lens 111, the object-side lens surface 1111 (La) is convex, and the image-side lens surface 1112 (Lb) is concave. The second lens 112 in the first group is, for example, a lens made of resin. The second lens 112 in the first group has negative optical power. In the second lens 112, the object-side lens surface 1121 (La) is convex, and the image-side lens surface 1122 (Lb) is concave. Both surfaces of the second lens 112 in the first group are aspherical.

[0176] The second group of first lenses 121 is, for example, a lens made of resin. The second group of first lenses 121 has negative optical power. In the second group of first lenses 121, the lens surface 1211 on the object side La is concave, and the lens surface 1212 on the image side Lb is convex. Both surfaces of the second group of first lenses 121 are aspherical. The second group of second lenses 122 is, for example, a lens made of resin. The second group of second lenses 122 has positive optical power. In the second group of second lenses 122, the lens surface 1221 on the object side La is convex, and the lens surface 1222 on the image side Lb is convex. Both surfaces of the second group of second lenses 122 are aspherical. The second group of third lenses 123 is, for example, a lens made of resin. The second group of third lenses 123 has positive optical power. In the second group of third lenses 123, the lens surface 1231 on the object side La is concave, and the convex lens surface 1232 on the image side Lb is convex. Both surfaces of the second group of third lenses 123 are aspherical.

[0177] The first lens 201 in the rear group is, for example, a lens made of glass. The first lens 201 in the rear group has positive power. In the first lens 201 in the rear group, the lens surface 2011 on the object side La is convex, and the lens surface 2012 on the image side Lb is convex. The second lens 202 in the rear group is, for example, a lens made of resin. The second lens 202 in the rear group has negative power. In the second lens 202 in the rear group, the lens surface 2021 on the object side La is concave, and the lens surface 2022 on the image side Lb is concave. Both surfaces of the second lens 202 in the rear group are aspherical. The third lens 203 in the rear group is, for example, a lens made of resin. The third lens 203 in the rear group has positive power. In the third lens 203 in the rear group, the lens surface 2031 on the object side La is convex, and the lens surface 2032 on the image side Lb is convex. Both surfaces of the third lens 203 in the rear group are aspherical.

[0178] Here, the second lens 202 and the third lens 203 of the rear group are a combined lens 204, wherein the lens surface 2022 of the image side Lb of the second lens 202 and the lens surface 2031 of the object side La of the third lens 203 are joined by, for example, an adhesive (not shown). According to this structure, the rear group 20 includes the combined lens 204, thereby allowing for appropriate correction of chromatic aberration.

[0179] The fourth lens 205 in the rear group is, for example, a lens made of resin. The fourth lens 205 in the rear group has positive optical power. In the fourth lens 205 in the rear group, the lens surface 2051 on the object side La is convex, and the lens surface 2052 on the image side Lb is concave. Both surfaces of the fourth lens 205 in the rear group are aspherical.

[0180] (Lens structure)

[0181] Figure 20This is a diagram showing the data of the wide-angle lens 1 in Embodiment 4. Figure 20 The values ​​shown have been rounded to the nearest whole number. The wide-angle lens 1 of this embodiment satisfies the conditional expressions (1) to (13) described in Embodiment 1.

[0182] In this embodiment, ν4=21.62 ν5 = 56.13. Therefore, ν4 = 21.62, satisfying condition (1). Also, ν5 = 56.13, satisfying conditions (2) and (2a).

[0183] In this embodiment, f0 = 2.871 mm f45 = 7.657 mm. Therefore, f45 / f0 = 2.667, which satisfies condition (3).

[0184] In this embodiment, f0 = 2.871 mm f345 = 13.514 mm. Therefore, f345 / f0 = 4.707, which satisfies condition (4).

[0185] In this embodiment, R22 = 3.818 mm R31 = -5.808 mm. Therefore, R22 / R31 = -0.657, which satisfies condition (5).

[0186] In this embodiment, f0 = 2.871 mm R22 = 3.818 mm R31 = -5.808 mm. Therefore, R22 / f0 = 1.330, satisfying condition (6). And, R31 / f0 = -2.023, satisfying condition (7).

[0187] In this embodiment, N9 = 1.663. Therefore, N9 = 1.663 satisfies condition (8).

[0188] In this embodiment, R61 = 8.509 mm R62 = -6.523 mm. Therefore, condition (9) is satisfied.

[0189] In this embodiment, ν7=21.62 ν8 = 56.13. Therefore, ν7 = 21.62, satisfying condition (10). And, ν8 = 56.13, satisfying condition (11).

[0190] In this embodiment, d0 = 27.450 mm f0 = 2.871 mm. Therefore, d0 / f0 = 9.562, which satisfies condition (12).

[0191] In this embodiment, ω = 94°. Therefore, condition (13) is satisfied.

[0192] (Function and effect)

[0193] The wide-angle lens 1 in Embodiment 4 is the same as that in Embodiment 1, satisfying conditions (1) to (13), and thus can achieve the same effect as in Embodiment 1.

[0194] Figure 21 It is shown Figure 19 The diagram shows the spherical aberration of the wide-angle lens 1. Figure 22 It is shown Figure 19 The diagram shows the chromatic aberration of the wide-angle lens 1. Figure 23 It is shown Figure 19 The diagram shows the astigmatism and distortion of the wide-angle lens 1. Figure 24 It is shown Figure 19 The diagram shows the lateral aberration of the wide-angle lens 1.

[0195] like Figures 21 to 24 As shown, in the wide-angle lens 1 of this embodiment, spherical aberration, magnification chromatic aberration, astigmatism (distortion) and lateral aberration are corrected to appropriate levels.

[0196] (Implementation Method 5)

[0197] Figure 25 This is an explanatory diagram of the wide-angle lens 1 according to Embodiment 5 of this disclosure. Figure 25 As shown, the wide-angle lens 1 of this embodiment includes a front group 10, an aperture 30, and a rear group 20 sequentially from the object side La to the image side Lb.

[0198] The front group 10, from the object side La to the image side Lb, comprises a first group 110 with negative optical power and a second group 120 with positive optical power. The first group 110, from the object side La to the image side Lb, is composed of a first group of first lenses 111 and a first group of second lenses 112. The second group 120, from the object side La to the image side Lb, is composed of a second group of first lenses 121, a second group of second lenses 122, and a second group of third lenses 123.

[0199] The rear group 20 is composed of a first lens 201, a second lens 202, a third lens 203, and a fourth lens 205, arranged sequentially from the object side La to the image side Lb. In addition, on the image side Lb of the fourth lens 205, a light-transmitting cover 40 and an imaging element 50 are arranged sequentially from the object side La to the image side Lb.

[0200] The first lens 111 in the first group is, for example, a lens made of glass. The first lens 111 in the first group has negative optical power. In the first lens 111, the object-side lens surface 1111 (La) is convex, and the image-side lens surface 1112 (Lb) is concave. The second lens 112 in the first group is, for example, a lens made of resin. The second lens 112 in the first group has negative optical power. In the second lens 112, the object-side lens surface 1121 (La) is convex, and the image-side lens surface 1122 (Lb) is concave. Both surfaces of the second lens 112 in the first group are aspherical.

[0201] The second group of first lenses 121 is, for example, a lens made of resin. The second group of first lenses 121 has negative optical power. In the second group of first lenses 121, the lens surface 1211 on the object side La is concave, and the lens surface 1212 on the image side Lb is convex. Both surfaces of the second group of first lenses 121 are aspherical. The second group of second lenses 122 is, for example, a lens made of resin. The second group of second lenses 122 has positive optical power. In the second group of second lenses 122, the lens surface 1221 on the object side La is convex, and the lens surface 1222 on the image side Lb is convex. Both surfaces of the second group of second lenses 122 are aspherical. The second group of third lenses 123 is, for example, a lens made of resin. The second group of third lenses 123 has positive optical power. In the second group of third lenses 123, the lens surface 1231 on the object side La is concave, and the lens surface 1232 on the image side Lb is convex. Both surfaces of the second group of third lenses 123 are aspherical.

[0202] The first lens 201 in the rear group is, for example, a lens made of glass. The first lens 201 in the rear group has positive power. In the first lens 201 in the rear group, the lens surface 2011 on the object side La is convex, and the lens surface 2012 on the image side Lb is convex. The second lens 202 in the rear group is, for example, a lens made of resin. The second lens 202 in the rear group has negative power. In the second lens 202 in the rear group, the lens surface 2021 on the object side La is concave, and the lens surface 2022 on the image side Lb is concave. Both surfaces of the second lens 202 in the rear group are aspherical. The third lens 203 in the rear group is, for example, a lens made of resin. The third lens 203 in the rear group has positive power. In the third lens 203 in the rear group, the lens surface 2031 on the object side La is convex, and the lens surface 2032 on the image side Lb is convex. Both surfaces of the third lens 203 in the rear group are aspherical.

[0203] Here, the second lens 202 and the third lens 203 of the rear group are a combined lens 204, wherein the lens surface 2022 of the image side Lb of the second lens 202 and the lens surface 2031 of the object side La of the third lens 203 are joined by, for example, an adhesive (not shown). According to this structure, the rear group 20 includes the combined lens 204, thereby allowing for appropriate correction of chromatic aberration.

[0204] The fourth lens 205 in the rear group is, for example, a lens made of resin. The fourth lens 205 in the rear group has positive optical power. In the fourth lens 205 in the rear group, the lens surface 2051 on the object side La is convex, and the lens surface 2052 on the image side Lb is concave. Both surfaces of the fourth lens 205 in the rear group are aspherical.

[0205] (Lens structure)

[0206] Figure 26 This is a diagram showing the data of the wide-angle lens 1 in embodiment 5. Figure 26 The values ​​shown have been rounded to the nearest whole number. The wide-angle lens 1 of this embodiment satisfies the conditional expressions (1) to (13) described in Embodiment 1.

[0207] In this embodiment, ν4=21.62 ν5 = 56.13. Therefore, ν4 = 21.62, satisfying condition (1). Also, ν5 = 56.13, satisfying conditions (2) and (2a).

[0208] In this embodiment, f0 = 2.872 mm f45 = 7.737 mm. Therefore, f45 / f0 = 2.694, which satisfies condition (3).

[0209] In this embodiment, f0 = 2.872 mm f345 = 13.312 mm. Therefore, f345 / f0 = 4.634, which satisfies condition (4).

[0210] In this embodiment, R22 = 3.804 mm R31 = -6.021 mm. Therefore, R22 / R31 = -0.632, which satisfies condition (5).

[0211] In this embodiment, f0 = 2.872 mm R22 = 3.804 mm R31 = -6.021 mm. Therefore, R22 / f0 = 1.324, satisfying condition (6). And, R31 / f0 = -2.096, satisfying condition (7).

[0212] In this embodiment, N9 = 1.663. Therefore, N9 = 1.663 satisfies condition (8).

[0213] In this embodiment, R61 = 8.679 mm R62 = -6.653 mm. Therefore, condition (9) is satisfied.

[0214] In this embodiment, ν7=21.62 ν8 = 56.13. Therefore, ν7 = 21.62, satisfying condition (10). And, ν8 = 56.13, satisfying condition (11).

[0215] In this embodiment, d0 = 27.733 mm f0 = 2.872 mm. Therefore, d0 / f0 = 9.655, which satisfies condition (12).

[0216] In this embodiment, ω = 94°. Therefore, condition (13) is satisfied.

[0217] (Function and effect)

[0218] The wide-angle lens 1 in Embodiment 5 is the same as that in Embodiment 1, satisfying conditions (1) to (13), and thus can achieve the same effect as in Embodiment 1.

[0219] Figure 27 It is shown Figure 25 The diagram shows the spherical aberration of the wide-angle lens 1. Figure 28 It is shown Figure 25 The diagram shows the chromatic aberration of the wide-angle lens 1. Figure 29 It is shown Figure 25 The diagram shows the astigmatism and distortion of the wide-angle lens 1. Figure 30 It is shown Figure 25 The diagram shows the lateral aberration of the wide-angle lens 1.

[0220] like Figures 27 to 30 As shown, in the wide-angle lens 1 of this embodiment, spherical aberration, magnification chromatic aberration, astigmatism (distortion) and lateral aberration are corrected to appropriate levels.

[0221] This technology can be configured as follows.

[0222] (1) A wide-angle lens, From the object side to the image side, the components are arranged in the following order: front group, aperture, and rear group. The front group, from the object side to the image side, includes a first group with negative optical power and a second group with positive optical power. The second group, from the object side to the image side, includes a second group of first lenses, a second group of second lenses, and a second group of third lenses. When the Abbe number of the second lens in the second group is set to ν4 and the Abbe number of the third lens in the second group is set to ν5, the following conditions (1) and (2) are satisfied: ν4<30.00……(1) 44.00<ν5……(2) (2) According to the wide-angle lens described in (1), wherein, When the focal distance of the entire lens system is set to f0, and the combined focal distance of the second lens of the second group and the third lens of the second group is set to f45, the following condition (3) is satisfied: 2.000<f45 / f0<3.500……(3) (3) According to the wide-angle lens described in (1), wherein, When the focal distance of the entire lens system is set to f0, and the combined focal distance of the first lens of the second group, the second lens of the second group, and the third lens of the second group is set to f345, the following condition (4) is satisfied: 2.000<f345 / f0<6.000……(4) (4) According to the wide-angle lens described in (1), wherein, The object-side lens surface of the second lens in the second group is a convex curved surface with at least one inflection point, and the image-side lens surface is also a convex curved surface.

[0223] (5) According to the wide-angle lens described in (1), wherein, The second lens in the second group and / or the third lens in the second group are lenses made of resin.

[0224] (6) The wide-angle lens according to (1), wherein, The first group, from the object side to the image side, includes a first group of first lenses and a first group of second lenses. The second lens in the first group has negative optical power, and the image-side lens surface is a concave curved surface. The second group of first lenses has negative optical power, and the object-side lens surface is a concave curved surface. When the radius of curvature of the image-side lens surface of the first group of second lenses is set to R22, and the radius of curvature of the object-side lens surface of the second group of first lenses is set to R31, the following condition (5) is satisfied: -1.000<R22 / R31<-0.500……(5) (7) The wide-angle lens according to (1), wherein, The first group, from the object side to the image side, includes a first group of first lenses and a first group of second lenses. The second lens in the first group has negative optical power, and the image-side lens surface is a concave curved surface. The second group of first lenses has negative optical power, and the object-side lens surface is a concave curved surface. When the focal distance of the entire lens system is set to f0, the radius of curvature of the image-side lens surface of the first group of second lenses is set to R22, and the radius of curvature of the object-side lens surface of the second group of first lenses is set to R31, the following conditions (6) and (7) are satisfied: 1.100<R22 / f0<3.000……(6) -3.000<R31 / f0<-1.100……(7) (8) The wide-angle lens according to (1), wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. The second and third lenses in the rear group are joined lenses, with the image-side lens surface of the second lens and the object-side lens surface of the third lens joined together. The fourth lens in the rear group has positive optical power, its object-side lens surface is a convex surface with at least one inflection point, and its image-side lens surface is a concave surface with at least one inflection point. When the d-line refractive index of the fourth lens in the rear group is set to N9, the following condition (8) is satisfied: 1.500 < N9……(8) (9) The wide-angle lens according to (1), wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. When the radius of curvature of the object-side lens surface of the first lens group is set to R61 and the radius of curvature of the image-side lens surface of the first lens group is set to R62, the following condition (9) is satisfied: |R61|>|R62| ……(9) (10) The wide-angle lens according to (1), wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. When the Abbe number of the second lens in the rear group is set to ν7 and the Abbe number of the third lens in the rear group is set to ν8, the following conditions (10) and (11) are satisfied: ν7<30.00……(10) 50.00<ν8……(11) (11) According to the wide-angle lens described in (1), wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. The fourth lens in the rear group is a single lens with positive focal length.

[0225] (12) A wide-angle lens according to any one of (1) to (11), wherein, When the object-image distance of the entire lens system is set to d0 and the focal distance of the entire lens system is set to f0, the following condition (12) is satisfied: 6.000<d0 / f0<12.000……(12) (13) A wide-angle lens according to any one of (1) to (11), wherein, When the maximum half field of view is set to ω, the following condition (13) is satisfied: 75°<ω<110°......(13) These novel embodiments can be implemented in various other ways, with various omissions, substitutions, modifications, and combinations possible without departing from the spirit of the invention. These embodiments are intended to fall within the scope and spirit of the invention and are included within the scope of the invention and its equivalents as described in the appended claims.

[0226] Symbol Explanation

[0227] 1... Wide-angle lens, 10... Front group, 20... Rear group, 30... Aperture, 50... Image sensor, 110... First group, 111... First lens of the first group, 112... Second lens of the first group, 120... Second group, 121... First lens of the second group, 122... Second lens of the second group, 123... Third lens of the second group, 201... First lens of the rear group, 202... Second lens of the rear group, 203... Third lens of the rear group, 204... Combined lens, 205... Fourth lens of the rear group.

Claims

1. A wide-angle lens, From the object side to the image side, the components are arranged in the following order: front group, aperture, and rear group. The front group, from the object side to the image side, includes a first group with negative optical power and a second group with positive optical power. The second group, from the object side to the image side, includes a second group of first lenses, a second group of second lenses, and a second group of third lenses. When the Abbe number of the second lens in the second group is set to ν4 and the Abbe number of the third lens in the second group is set to ν5, the following conditions (1) and (2) are satisfied: ν4<30.00……(1) 44.00<ν5……(2)。 2. The wide-angle lens according to claim 1, wherein, When the focal distance of the entire lens system is set to f0, and the combined focal distance of the second lens of the second group and the third lens of the second group is set to f45, the following condition (3) is satisfied: 2.000<f45 / f0<3.500……(3).

3. The wide-angle lens according to claim 1, wherein, When the focal distance of the entire lens system is set to f0, and the combined focal distance of the first lens of the second group, the second lens of the second group, and the third lens of the second group is set to f345, the following condition (4) is satisfied: 2.000<f345 / f0<6.000……(4).

4. The wide-angle lens according to claim 1, wherein, The object-side lens surface of the second lens in the second group is a convex curved surface with at least one inflection point, and the image-side lens surface is also a convex curved surface.

5. The wide-angle lens according to claim 1, wherein, The second lens in the second group and / or the third lens in the second group are lenses made of resin.

6. The wide-angle lens according to claim 1, wherein, The first group, from the object side to the image side, includes a first group of first lenses and a first group of second lenses. The second lens in the first group has negative optical power, and the image-side lens surface is a concave curved surface. The second group of first lenses has negative optical power, and the object-side lens surface is a concave curved surface. When the radius of curvature of the image-side lens surface of the first group of second lenses is set to R22, and the radius of curvature of the object-side lens surface of the second group of first lenses is set to R31, the following condition (5) is satisfied: -1.000<R22 / R31<-0.500……(5).

7. The wide-angle lens according to claim 1, wherein, The first group, from the object side to the image side, includes a first group of first lenses and a first group of second lenses. The second lens in the first group has negative optical power, and the image-side lens surface is a concave curved surface. The second group of first lenses has negative optical power, and the object-side lens surface is a concave curved surface. When the focal distance of the entire lens system is set to f0, the radius of curvature of the image-side lens surface of the first group of second lenses is set to R22, and the radius of curvature of the object-side lens surface of the second group of first lenses is set to R31, the following conditions (6) and (7) are satisfied: 1.100<R22 / f0<3.000……(6) -3.000<R31 / f0<-1.100……(7).

8. The wide-angle lens according to claim 1, wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. The second and third lenses in the rear group are joined lenses, with the image-side lens surface of the second lens and the object-side lens surface of the third lens joined together. The fourth lens in the rear group has positive optical power, its object-side lens surface is a convex surface with at least one inflection point, and its image-side lens surface is a concave surface with at least one inflection point. When the refractive index of the d-line of the fourth lens in the rear group is set to N9, the following condition (8) is satisfied: 1.500＜N9……（8）。 9. The wide-angle lens according to claim 1, wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. When the radius of curvature of the object-side lens surface of the first lens group is set to R61 and the radius of curvature of the image-side lens surface of the first lens group is set to R62, the following condition (9) is satisfied: |R61|>|R62| ……(9).

10. The wide-angle lens according to claim 1, wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. When the Abbe number of the second lens in the rear group is set to v7 and the Abbe number of the third lens in the rear group is set to v8, the following conditions (10) and (11) are satisfied: ν7<30.00……(10) 50.00<ν8……(11)。 11. The wide-angle lens according to claim 1, wherein, The rear group, from the object side to the image side, includes a first rear lens, a second rear lens, a third rear lens, and a fourth rear lens. The fourth lens in the rear group is a single lens with positive focal length.

12. The wide-angle lens according to any one of claims 1 to 11, wherein, When the object-image distance of the entire lens system is set to d0 and the focal distance of the entire lens system is set to f0, the following condition (12) is satisfied: 6.000<d0 / f0<12.000……(12).

13. The wide-angle lens according to any one of claims 1 to 11, wherein, When the maximum half field of view is set to ω, the following condition (13) is satisfied: 75°<ω<110°......(13).

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