Wide-angle lens

Abstract

A wide-angle lens which easily and appropriately corrects various aberrations such as field curvature, magnification chromatic aberration, and coma aberration, and easily achieves miniaturization of the entire wide-angle lens. The wide-angle lens of the present invention includes, in order from the object side, a first lens which is a negative lens with a concave image side lens surface, a second lens which is a negative lens with a concave image side lens surface, a third lens which is a positive lens with a convex image side lens surface, a fourth lens which is a positive lens with a convex image side lens surface, a fifth lens which is a positive lens, a sixth lens which is a negative lens, and a seventh lens which is a positive lens, and satisfies the following relationship when a focal length of the third lens is set as f3 and a focal length of the entire wide-angle lens is set as f: 3.000 < f3 / f < 12.500.

Description

Technical Field

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

[0002] As a wide-angle lens for vehicle cameras, there is a conventional wide-angle lens that includes a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-60153

[0004] In practice, in order to achieve good optical characteristics, it is desirable to be able to easily correct various aberrations of wide-angle lenses, such as field curvature, magnification chromatic aberration, and coma. On the other hand, the overall size of the space in a vehicle for mounting such wide-angle lenses is sometimes limited. Therefore, it is desirable to achieve miniaturization of the wide-angle lens as a whole. Summary of the Invention

[0005] The present invention was made in view of the above-mentioned problems, and its purpose is to provide a wide-angle lens that can easily and appropriately correct various aberrations such as field curvature, magnification chromatic aberration, and coma, and can easily achieve the miniaturization of the wide-angle lens as a whole.

[0006] To achieve the above objectives, the present invention provides a wide-angle lens comprising, sequentially arranged from the object side, a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens. The first lens is a negative lens with a concave image-side lens surface, the second lens is a negative lens with a concave image-side lens surface, the third lens is a positive lens with a convex image-side lens surface, the fourth lens is a positive lens with a convex image-side lens surface, the fifth lens is a positive lens, the sixth lens is a negative lens, and the seventh lens is a positive lens. When the focal distance of the third lens is set to f3 and the focal distance of the entire wide-angle lens is set to f, the following relationship is satisfied: 3.000 < f3 / f < 12.500.

[0007] The wide-angle lens according to the present invention satisfies the relationship f3 / f > 3.000, thus avoiding excessive positive optical power of the third lens. As a result, it is easy to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. On the other hand, it satisfies the relationship f3 / f < 12.500, thus reducing the lens diameter and the distance between the object and the image, thereby achieving overall miniaturization of the wide-angle lens. Furthermore, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0008] Furthermore, in the wide-angle lens of the present invention, the following relationship is preferably satisfied: 5.000 < f3 / f < 10.000.

[0009] The wide-angle lens according to the present invention satisfies the relationship 5.000 < f3 / f < 10.000. Therefore, it is easier to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can further reduce the lens diameter and the distance between the object and the image, thereby achieving the miniaturization of the wide-angle lens as a whole.

[0010] Furthermore, in the wide-angle lens of the present invention, it is preferable that when the focal distance of the fourth lens is set to f4, the following relationship is satisfied: 4.000 < f4 / f < 7.000.

[0011] The wide-angle lens according to the present invention satisfies the relationship f4 / f > 4.000, thus avoiding excessive positive optical focal length. As a result, it is easy to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. On the other hand, it satisfies the relationship f4 / f < 7.000, thus reducing the lens diameter and the distance between the object and the image, thereby achieving miniaturization of the wide-angle lens as a whole.

[0012] Furthermore, in the wide-angle lens of the present invention, the following relationship is preferably satisfied: 4.500 < f4 / f < 6.000.

[0013] The wide-angle lens according to the present invention satisfies the relationship 4.500 < f4 / f < 6.000. Therefore, it is easier to properly correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can further reduce the lens diameter and the distance between the object and the image, thereby achieving the miniaturization of the wide-angle lens as a whole.

[0014] Furthermore, in the wide-angle lens of the present invention, it is preferable that when the radius of curvature of the object-side lens surface of the fourth lens is set to R41, the following relationship is satisfied: 10.000 < |R41 / f| < 40.000.

[0015] The wide-angle lens according to the present invention satisfies the relationship |R41 / f|>10.000. Therefore, the radius of curvature of the object-side lens surface of the fourth lens is large. Even if the light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light is not easily reflected at the object-side lens surface of the fourth lens and is not easily returned to the imaging element. Thus, ghosting can be suppressed. Furthermore, it satisfies the relationship |R41 / f|<40.000. Therefore, the optical power of the fourth lens can be ensured to be large. Thus, it is easy to properly correct various aberrations and achieve excellent optical characteristics.

[0016] Furthermore, in the wide-angle lens of the present invention, the following relationship is preferably satisfied: 13.000 < |R41 / f| < 30.000.

[0017] The wide-angle lens according to the present invention satisfies the relationship 13.000 < |R41 / f| < 30.000, thus further suppressing ghosting and making it easier to properly correct various aberrations, thereby achieving excellent optical characteristics.

[0018] Furthermore, in the wide-angle lens of the present invention, the fourth lens is preferably a positive lens with a concave object-side lens surface and a convex image-side lens surface. When the radius of curvature of the object-side lens surface of the fourth lens is set to R41, the following relationship is satisfied: -30.000 < R41 / f < -10.000.

[0019] The wide-angle lens according to the present invention satisfies the relationship R41 / f > -30.000, thus ensuring a large negative optical power of the object-side lens surface of the fourth lens. As a result, it is easy to appropriately correct various aberrations, thereby achieving excellent optical characteristics. On the other hand, it satisfies the relationship R41 / f < -10.000, so the radius of curvature of the object-side lens surface of the fourth lens will not be too small. Even if the light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light entering the fourth lens is not easily reflected at the object-side lens surface of the fourth lens and is not easily returned to the imaging element. As a result, ghosting can be suppressed.

[0020] Furthermore, in the wide-angle lens of the present invention, the following relationship is preferably satisfied: -25.000 < R41 / f < -12.000.

[0021] The wide-angle lens according to the present invention satisfies the relationship -25.000 < R41 / f < -12.000, thus making it easier to properly correct various aberrations, thereby achieving excellent optical characteristics and better suppressing ghosting.

[0022] Furthermore, in the wide-angle lens of the present invention, it is preferable that the sixth lens and the seventh lens constitute a combined lens, the fifth lens is a positive lens with a convex object-side lens surface and a convex image-side lens surface, the sixth lens is a negative lens with a concave image-side lens surface, and the seventh lens is a positive lens with a convex object-side lens surface and a convex image-side lens surface. When the combined focal distance of the first lens, the second lens, the third lens, and the fourth lens is set to f1234 and the combined focal distance of the fifth lens, the sixth lens, and the seventh lens is set to f567, the following relationship is satisfied: 0.800 < f1234 / f567 < 8.000.

[0023] The wide-angle lens according to the present invention satisfies the relationship f1234 / f567 > 0.800, thus avoiding excessive optical focal length of the front lens group composed of the first lens, second lens, third lens and fourth lens. As a result, it is easy to properly correct various aberrations and obtain excellent optical characteristics. On the other hand, it satisfies the relationship f1234 / f567 < 8.000, thus avoiding excessive optical focal length of the front lens group composed of the first lens, second lens, third lens and fourth lens. As a result, the diameter of each lens in the front lens group can be reduced, and the overall miniaturization of the lens system can be easily achieved.

[0024] Furthermore, in the wide-angle lens of the present invention, it is preferable that the sixth lens and the seventh lens constitute a combined lens, the fifth lens is a positive lens with a convex object-side lens surface and a convex image-side lens surface, the sixth lens is a negative lens with a concave image-side lens surface, and the seventh lens is a positive lens with a convex object-side lens surface and a convex image-side lens surface. When the combined focal distance of the fifth lens, the sixth lens, and the seventh lens is set to f567 and the focal distance of the entire wide-angle lens is set to f, the following relationship is satisfied: 2.800 < f567 / f < 3.850.

[0025] The wide-angle lens according to the present invention satisfies the relationship f567 / f > 2.800, thus avoiding excessive optical focal length in the rear lens group composed of the fifth, sixth, and seventh lenses. As a result, it is easy to appropriately correct various aberrations, especially chromatic aberration, thereby easily obtaining excellent optical characteristics. On the other hand, it satisfies the relationship f567 / f < 3.850, thus reducing the diameter of each lens and the distance between the object and the image, thereby further realizing the miniaturization of the wide-angle lens as a whole.

[0026] Furthermore, in the wide-angle lens of the present invention, it is preferable that when the object-image distance of the wide-angle lens is set as d and the focal distance of the wide-angle lens as f, the following relationship is satisfied: 11.000 < d / f < 15.000.

[0027] The wide-angle lens according to the present invention satisfies the relationship d / f > 11.000, thus making it easy to appropriately correct various aberrations and thereby easily obtain excellent optical characteristics; on the other hand, it satisfies the relationship d / f < 15.000, thus preventing the overall length of the lens system from becoming too long while suppressing the lens system from becoming too large.

[0028] Furthermore, in the wide-angle lens of the present invention, it is preferable that the first lens and the fifth lens are glass lenses, and the second lens, the third lens, the fourth lens, the sixth lens and the seventh lens are plastic lenses.

[0029] (Invention Effects)

[0030] According to the present invention, when the focal distance of the third lens is set to f3 and the focal distance of the entire wide-angle lens is set to f, the relationship f3 / f > 3.000 is satisfied. Therefore, the positive optical power of the third lens can be avoided, and various aberrations such as field curvature, chromatic aberration, and coma can be easily and appropriately corrected, thereby achieving excellent optical characteristics. On the other hand, the relationship f3 / f < 12.500 is satisfied, so the lens diameter and the distance between the object and the image can be reduced, thereby achieving miniaturization of the entire wide-angle lens. Furthermore, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses, and making it easier to achieve miniaturization of the entire wide-angle lens. Attached Figure Description

[0031] Figure 1 This is an explanatory diagram showing the wide-angle lens according to Embodiment 1 of the present invention.

[0032] Figure 2A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 1 of the present invention.

[0033] Figure 2B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 1 of the present invention.

[0034] Figure 3A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 1 of the present invention.

[0035] Figure 3B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 1 of the present invention.

[0036] Figures 4A to 4L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 1 of the present invention.

[0037] Figure 5 This is an explanatory diagram showing the wide-angle lens according to Embodiment 2 of the present invention.

[0038] Figure 6A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 2 of the present invention.

[0039] Figure 6B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 2 of the present invention.

[0040] Figure 7A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 2 of the present invention.

[0041] Figure 7BThis is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 2 of the present invention.

[0042] Figures 8A to 8L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 2 of the present invention.

[0043] Figure 9 This is an explanatory diagram showing the wide-angle lens of Embodiment 3 of the present invention.

[0044] Figure 10A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 3 of the present invention.

[0045] Figure 10B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 3 of the present invention.

[0046] Figure 11A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 3 of the present invention.

[0047] Figure 11B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 3 of the present invention.

[0048] Figures 12A to 12L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 3 of the present invention.

[0049] Figure 13 This is an explanatory diagram showing the wide-angle lens of Embodiment 4 of the present invention.

[0050] Figure 14A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 4 of the present invention.

[0051] Figure 14B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 4 of the present invention.

[0052] Figure 15A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 4 of the present invention.

[0053] Figure 15B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 4 of the present invention.

[0054] Figures 16A to 16L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 4 of the present invention.

[0055] Figure 17 This is an explanatory diagram showing the wide-angle lens of Embodiment 5 of the present invention.

[0056] Figure 18AThis is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 5 of the present invention.

[0057] Figure 18B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 5 of the present invention.

[0058] Figure 19A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 5 of the present invention.

[0059] Figure 19B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 5 of the present invention.

[0060] Figures 20A to 20L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 5 of the present invention.

[0061] Figure 21 This is an explanatory diagram showing the wide-angle lens according to Embodiment 6 of the present invention.

[0062] Figure 22A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 6 of the present invention.

[0063] Figure 22B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 6 of the present invention.

[0064] Figure 23A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 6 of the present invention.

[0065] Figure 23B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 6 of the present invention.

[0066] Figures 24A to 24L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 6 of the present invention.

[0067] (Symbol Explanation)

[0068] 1000 wide-angle lens

[0069] 110 First Lens

[0070] 120 Second Lens

[0071] 130 Third Lens

[0072] 140 Fourth Lens

[0073] 150 Fifth Lens

[0074] 160 Sixth Lens

[0075] 170 Seventh Lens

[0076] 180 aperture

[0077] 190 light-blocking sheet

[0078] 200 filters

[0079] 300 camera elements Detailed Implementation

[0080] Hereinafter, various embodiments of the wide-angle lens of the present invention will be described with reference to the accompanying drawings. Furthermore, in the following description, the object side will be labeled L1 and the image side L2 in the direction of extension of the optical axis L.

[0081] (Implementation Method 1)

[0082] Figure 1 This is an explanatory diagram showing the wide-angle lens according to Embodiment 1 of the present invention. Figure 2A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 1 of the present invention. Figure 2B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 1 of the present invention. Figure 3A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 1 of the present invention. Figure 3B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 1 of the present invention. Figures 4A to 4L This is an explanatory diagram illustrating the lateral aberration of the wide-angle lens according to Embodiment 1 of the present invention. Here, in Figure 2A , Figure 2B , Figure 3A , Figure 3B , Figures 4A to 4L In the diagram, the correlation curve for red light R (wavelength 656nm) is labeled R, the correlation curve for green light G (wavelength 588nm) is labeled G, and the correlation curve for blue light B (wavelength 486nm) is labeled B. T represents correlation with the meridional plane, and S represents correlation with the sagittal plane. Furthermore, in... Figures 4A to 4L In the figure, the maximum scale of the vertical axis is ±50.000 μm.

[0083] like Figure 1 As shown, the wide-angle lens 1000 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged sequentially from the object side (L1 side). The sixth lens 160 and the seventh lens 170 are bonded together with an adhesive to form a joint lens.

[0084] Here, the first lens 110 is a lens with negative optical power (referred to as a negative lens) whose convex surface (first surface 1) faces the object side L1 and whose concave surface (second surface 2) faces the image side L2. In this embodiment, the first lens 110 is a glass lens in which the first surface 1 and the second surface 2 are spherical.

[0085] The second lens 120 is a lens with negative optical power, having a convex surface (third surface 3) facing the object side L1 and a concave surface (fourth surface 4) facing the image side L2. In this embodiment, the second lens 120 is a plastic lens with aspherical surfaces for the third surface 3 and the fourth surface 4.

[0086] The third lens 130 is a lens with positive optical power (referred to as a positive lens) whose concave surface (fifth surface 5) faces the object side L1 and whose convex surface (sixth surface 6) faces the image side L2. In this embodiment, the third lens 130 is a plastic lens with aspherical fifth surface 5 and sixth surface 6.

[0087] The fourth lens 140 is a lens with positive optical power, having a concave surface (seventh surface 7) facing the object side L1 and a convex surface (eighth surface 8) facing the image side L2. In this embodiment, the fourth lens 140 is a plastic lens with aspherical surfaces for the seventh surface 7 and the eighth surface 8.

[0088] The fifth lens 150 is a lens with positive optical power, having a convex surface (tenth surface 10) facing the object side L1 and a convex surface (eleventh surface 11) facing the image side L2. In this embodiment, the fifth lens 150 is made of a glass lens.

[0089] The sixth lens 160 is a lens with negative optical power, having a concave surface (twelfth surface 12) facing the object side L1 and a concave surface (thirteenth surface 13) facing the image side L2, and forms a combined lens with the seventh lens 170. In this embodiment, the sixth lens 160 is a plastic lens with aspherical surfaces for the twelfth surface 12 and the thirteenth surface 13.

[0090] The seventh lens 170 is a lens with positive optical power, where the convex surface (thirteenth surface 13) faces the object side L1 and the convex surface (fourteenth surface 14) faces the image side L2. In this embodiment, the seventh lens 170 is a plastic lens where the thirteenth surface 13 and the fourteenth surface 14 are aspherical.

[0091] Furthermore, in this embodiment, such as Figure 1 As shown, a light-shielding plate 190 is provided between the second lens 120 and the fourth lens 130, a filter 200 is provided on the image side of the seventh lens 170, and an image sensor 300 is provided on the image side of the filter 200.

[0092] In this embodiment, the overall focal length f (Effective Focal Length) of the lens system is 1.023 mm, the object-to-image distance d (Total Track) is 13.611 mm, the image space F / # is 2.02, the maximum field of view is 115 degrees, and the entrance pupil diameter HEP is 0.507 mm.

[0093] Table 1 shows the physical properties of each facet of the wide-angle lens 1000 of this embodiment, and Tables 2-1 and 2-2 show the aspherical coefficients of each facet of the wide-angle lens 1000 of this embodiment.

[0094] (Table 1)

[0095]

[0096] In Table 1 above, the units for radius of curvature, thickness, focal distance, and effective radius are mm, Nd is the refractive index of light at 587.56 nanometers, νd is the Abbe number, and * indicates an aspherical surface.

[0097] (Table 2-1)

[0098]

[0099] (Table 2-2)

[0100] noodle A8 A10 A12 A14 A16 3 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 4 -3.29328E-03 2.82298E-03 -4.88754E-04 0.00000E+00 0.00000E+00 5 -5.12306E-03 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 6 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 7 4.37857E-03 2.92148E-03 0.00000E+00 0.00000E+00 0.00000E+00 8 -5.94177E-03 1.11565E-02 0.00000E+00 0.00000E+00 0.00000E+00 12 1.79956E-02 -7.87537E-04 -1.30556E-03 0.00000E+00 0.00000E+00 13 1.73181E-01 -4.77496E-02 4.65741E-03 0.00000E+00 0.00000E+00 14 1.34046E-02 -4.35536E-03 5.73510E-04 0.00000E+00 0.00000E+00

[0101] In Tables 2-1 and 2-2 above, when the lens surface is a convex surface protruding towards the object side or a concave surface recessed towards the object side, the radius of curvature is set to a positive value; when the lens surface is a convex surface protruding towards the image side or a concave surface recessed towards the image side, the radius of curvature is set to a negative value.

[0102] Furthermore, Tables 2-1 and 2-2 above show the aspherical coefficients A4, A6, A8, A10, A12, A14, and A16 for each aspherical surface shape, expressed by the following formula (Mathematical Formula 1). In the following formula, the sag (the axis in the direction of the optical axis) is set as Z, the height in the direction perpendicular to the optical axis (the height of the ray) is set as r, the conic coefficient is set as K, and the reciprocal of the radius of curvature is set as c.

[0103] [Mathematical Expression 1]

[0104]

[0105] Here, in the wide-angle lens 1000, the focal distance f3 of the third lens 130 is 6.742 mm, and the focal distance f of the entire lens system is 1.023 mm. Therefore, the following condition 1 is satisfied:

[0106] 3.000 < f3 / f < 12.500.

[0107] In condition 1, if f3 / f is less than 3.000, the positive optical focal length of the third lens is too large, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f3 / f is greater than 12.500, it is difficult to reduce the diameter of the third lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0108] In contrast, in this embodiment, since condition 1 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0109] In particular, in this embodiment, since the relationship 5.000 < f3 / f < 10.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0110] Furthermore, in the wide-angle lens 1000, the focal distance f4 of the fourth lens 140 is 4.923 mm, and the focal distance f of the entire lens system is 1.023 mm. Therefore, the following condition 2 is satisfied:

[0111] 4.000 < f4 / f < 7.000.

[0112] In condition 2, if f4 / f is below 4.000, the positive optical focal length of the fourth lens is too strong, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f4 / f is above 7.000, it is difficult to reduce the diameter of the fourth lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0113] In contrast, in this embodiment, since condition 2 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0114] In particular, in this embodiment, since the relationship 4.500 < f4 / f < 6.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0115] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -13.315 mm, and the focal distance f of the entire lens system is 1.023 mm. Therefore, the following condition 3 is satisfied:

[0116] 10.000 < |R41 / f| < 40.000.

[0117] In condition 3, if |R41 / f| is less than or equal to 10.000, the radius of curvature of the object-side lens surface of the fourth lens is small. When light reaching the image sensor is reflected off the surface of the image sensor and enters the fourth lens, the light is easily reflected off the object-side lens surface of the fourth lens and returns to the image sensor. As a result, ghosting is likely to occur. On the other hand, if |R41 / f| is greater than or equal to 40.000, the optical power of the fourth lens is small, and it is not easy to correct various aberrations.

[0118] In contrast, in this embodiment, since condition 3 is satisfied, it has the advantages of suppressing ghosting and easily and appropriately correcting various aberrations.

[0119] In particular, in this embodiment, since the relationship 13.000 < |R41 / f| < 30.000 is satisfied, it has the advantage of further suppressing the generation of ghosting and making it easier to properly correct various aberrations.

[0120] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -13.315 mm, and the focal distance f of the entire lens system is 1.023 mm. Therefore, the following condition 4 is satisfied:

[0121] -30.000 < R41 / f < -10.000.

[0122] In condition 4, if R41 / f is below -30.000, the negative optical power of the object-side lens surface of the fourth lens is small, making it difficult to properly correct various aberrations. On the other hand, if R41 / f is above -10.000, the radius of curvature of the object-side lens surface of the fourth lens is too small. When light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light is easily reflected at the object-side lens surface of the fourth lens and returns to the imaging element, which easily produces ghosting.

[0123] In contrast, in this embodiment, since condition 4 is satisfied, it has the advantage of being able to easily and appropriately correct various aberrations and suppress ghosting.

[0124] In particular, in this embodiment, since the relationship -25.000 < R41 / f < -12.000 is satisfied, it has the advantage of making it easier to properly correct various aberrations and further suppress ghosting.

[0125] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f1234 of the first lens 110, second lens 120, third lens 130, and fourth lens 140 is 3.148 mm, and the combined focal distance f567 of the fifth lens 150, sixth lens 160, and seventh lens 170 is 3.740 mm. Therefore, condition 5 is satisfied.

[0126] 0.800 < f1234 / f567 < 8.000.

[0127] In condition 5, if f1234 / f567 is below 0.800, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too strong, making it difficult to properly correct various aberrations. On the other hand, if f1234 / f is above 8.000, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too weak, making it difficult to reduce the diameter of each lens in the front lens group and to achieve overall miniaturization of the wide-angle lens.

[0128] In contrast, in this embodiment, since condition 5 is satisfied, it has the advantages of making it easier to properly correct various aberrations and making it easier to achieve miniaturization.

[0129] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f567 of the fifth lens 150, the sixth lens 160, and the seventh lens 170 is 3.740 mm, and the overall focal distance f of the lens system is 1.023 mm. Therefore, condition 6 is satisfied:

[0130] 2.800 < f567 / f < 3.850

[0131] In condition 6, if f567 / f is below 2.800, the optical focal length of the rear lens group consisting of the fifth, sixth, and seventh lenses will be too strong, making it difficult to properly correct various aberrations, especially chromatic aberration. On the other hand, if f567 / f is above 3.850, it will be difficult to reduce the diameter of each lens and the distance between the object and the image, making it difficult to achieve the overall miniaturization of the wide-angle lens.

[0132] In contrast, in this embodiment, since condition 6 is satisfied, it has the advantages of being able to easily correct various aberrations, especially chromatic aberrations, and being easier to miniaturize.

[0133] Furthermore, in the wide-angle lens 1000, the object-image distance d is 13.611 mm, and the overall focal distance f of the lens system is 1.023 mm. Therefore, the following condition 7 is satisfied:

[0134] 11.000 < d / f < 15.000

[0135] In condition 7, if d / f is below 11.000, it is not easy to properly correct various aberrations. On the other hand, if d / f is above 15.000, the overall length of the lens system becomes too long.

[0136] In contrast, in this embodiment, since condition 7 is satisfied, it is easy to properly correct various aberrations, easily obtain excellent optical characteristics, and suppress the lens system from becoming too large while avoiding the overall length of the lens system becoming too long.

[0137] In summary, in this embodiment, by constructing the wide-angle lens 1000 in the manner described above, as follows... Figures 2A to 4L As shown, the positive optical power of the third lens can be avoided, thus making it easier to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can reduce the lens diameter and the distance between the object and the image, thus achieving overall miniaturization of the wide-angle lens. Moreover, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses and making it easier to achieve overall miniaturization of the wide-angle lens.

[0138] (Implementation Method 2)

[0139] Figure 5 This is an explanatory diagram showing the wide-angle lens according to Embodiment 2 of the present invention. Figure 6A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 2 of the present invention. Figure 6B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 2 of the present invention. Figure 7AThis is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 2 of the present invention. Figure 7B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 2 of the present invention. Figures 8A to 8L This is an explanatory diagram illustrating the lateral aberration of the wide-angle lens according to Embodiment 2 of the present invention. Here, in Figure 6A , Figure 6B , Figure 7A , Figure 7B , Figures 8A to 8L In the diagram, the correlation curve for red light R (wavelength 656nm) is labeled R, the correlation curve for green light G (wavelength 588nm) is labeled G, and the correlation curve for blue light B (wavelength 486nm) is labeled B. T represents correlation with the meridional plane, and S represents correlation with the sagittal plane. Furthermore, in... Figures 8A to 8L In the figure, the maximum scale of the vertical axis is ± 50.000 μm.

[0140] like Figure 5 As shown, the wide-angle lens 1000 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged sequentially from the object side (L1 side). The sixth lens 160 and the seventh lens 170 are bonded together with an adhesive to form a joint lens.

[0141] Since the basic structure of the wide-angle lens 1000 in this embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 have positive or negative optical power, whether they are glass lenses or plastic lenses, whether the object-side surface and the image-side surface are convex or concave, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in Embodiment 1, it will not be elaborated on here.

[0142] In addition, such as Figure 5 As shown, similar to Embodiment 1, a light-shielding sheet 190 is provided between the second lens 120 and the fourth lens 130, a filter 200 is provided on the image side of the seventh lens 170, and an image sensor 300 is provided on the image side of the filter 200.

[0143] In this embodiment, the overall focal length f (Effective Focal Length) of the lens system is 1.011 mm, the object-to-image distance d (Total Track) is 13.404 mm, the image space F / # is 2.03, the maximum field of view is 109 degrees, and the entrance pupil diameter HEP is 0.498 mm.

[0144] Table 3 shows the physical properties of each facet of the wide-angle lens 1000 of this embodiment, and Tables 4-1 and 4-2 show the aspherical coefficients of each facet of the wide-angle lens 1000 of this embodiment.

[0145] (Table 3)

[0146]

[0147] In Table 3 above, the units for radius of curvature, thickness, focal distance, and effective radius are mm, Nd is the refractive index of light at 587.56 nanometers, νd is the Abbe number, and * indicates an aspherical surface.

[0148] (Table 4-1)

[0149]

[0150] (Table 4-2)

[0151] noodle A8 A10 A12 A14 A16 3 -1.15147E-03 1.50789E-04 -7.30801E-06 0.00000E+00 0.00000E+00 4 7.01048E-02 -7.98133E-03 -4.17335E-03 0.00000E+00 0.00000E+00 5 1.21716E-02 -8.91664E-03 0.00000E+00 0.00000E+00 0.00000E+00 6 2.05279E-02 -2.11693E-02 5.41203E-03 0.00000E+00 0.00000E+00 7 6.15517E-03 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 8 8.49340E-03 3.83965E-03 -2.61241E-03 0.00000E+00 0.00000E+00 12 -5.25642E-02 5.03801E-02 -2.60337E-02 5.67639E-03 0.00000E+00 13 1.93193E-02 -2.02628E-02 1.27147E-02 -3.03203E-03 0.00000E+00 14 5.37377E-02 -2.41958E-02 5.72598E-03 -5.29799E-04 0.00000E+00

[0152] In Tables 4-1 and 4-2 above, when the lens surface is a convex surface protruding towards the object side or a concave surface recessed towards the object side, the radius of curvature is set to a positive value; when the lens surface is a convex surface protruding towards the image side or a concave surface recessed towards the image side, the radius of curvature is set to a negative value.

[0153] Furthermore, Tables 4-1 and 4-2 above show the aspherical coefficients A4, A6, A8, A10, A12, A14, and A16 when each face has an aspherical shape, as represented by the mathematical formula 1 above.

[0154] Here, in the wide-angle lens 1000, the focal distance f3 of the third lens 130 is 7.736 mm, and the focal distance f of the entire lens system is 1.011 mm. Therefore, the following condition 1 is satisfied:

[0155] 3.000 < f3 / f < 12.500.

[0156] In condition 1, if f3 / f is less than 3.000, the positive optical focal length of the third lens is too large, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f3 / f is greater than 12.500, it is difficult to reduce the diameter of the third lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0157] In contrast, in this embodiment, since condition 1 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0158] In particular, in this embodiment, since the relationship 5.000 < f3 / f < 10.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0159] Furthermore, in the wide-angle lens 1000, the focal distance f4 of the fourth lens 140 is 5.873 mm, and the focal distance f of the entire lens system is 1.011 mm. Therefore, the following condition 2 is satisfied:

[0160] 4.000 < f4 / f < 7.000.

[0161] In condition 2, if f4 / f is below 4.000, the positive optical focal length of the fourth lens is too strong, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f4 / f is above 7.000, it is difficult to reduce the diameter of the fourth lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0162] In contrast, in this embodiment, since condition 2 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0163] In particular, in this embodiment, since the relationship 4.500 < f4 / f < 6.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0164] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -20.063 mm, and the focal distance f of the entire lens system is 1.011 mm. Therefore, the following condition 3 is satisfied:

[0165] 10.000 < |R41 / f| < 40.000.

[0166] In condition 3, if |R41 / f| is less than or equal to 10.000, the radius of curvature of the object-side lens surface of the fourth lens is small. When light reaching the image sensor is reflected off the surface of the image sensor and enters the fourth lens, the light is easily reflected off the object-side lens surface of the fourth lens and returns to the image sensor. As a result, ghosting is likely to occur. On the other hand, if |R41 / f| is greater than or equal to 40.000, the optical power of the fourth lens is small, and it is not easy to correct various aberrations.

[0167] In contrast, in this embodiment, since condition 3 is satisfied, it has the advantages of suppressing ghosting and easily and appropriately correcting various aberrations.

[0168] In particular, in this embodiment, since the relationship 13.000 < |R41 / f| < 30.000 is satisfied, it has the advantage of further suppressing the generation of ghosting and making it easier to properly correct various aberrations.

[0169] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -20.063 mm, and the focal distance f of the entire lens system is 1.011 mm. Therefore, the following condition 4 is satisfied:

[0170] -30.000 < R41 / f < -10.000.

[0171] In condition 4, if R41 / f is below -30.000, the negative optical power of the object-side lens surface of the fourth lens is small, making it difficult to properly correct various aberrations. On the other hand, if R41 / f is above -10.000, the radius of curvature of the object-side lens surface of the fourth lens is too small. When light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light is easily reflected at the object-side lens surface of the fourth lens and returns to the imaging element, which easily produces ghosting.

[0172] In contrast, in this embodiment, since condition 4 is satisfied, it has the advantage of being able to easily and appropriately correct various aberrations and suppress ghosting.

[0173] In particular, in this embodiment, since the relationship -25.000 < R41 / f < -12.000 is satisfied, it has the advantage of making it easier to properly correct various aberrations and further suppress ghosting.

[0174] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f1234 of the first lens 110, second lens 120, third lens 130, and fourth lens 140 is 6.571 mm, and the combined focal distance f567 of the fifth lens 150, sixth lens 160, and seventh lens 170 is 3.355 mm. Therefore, condition 5 is satisfied.

[0175] 0.800 < f1234 / f567 < 8.000.

[0176] In condition 5, if f1234 / f567 is below 0.800, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too strong, making it difficult to properly correct various aberrations. On the other hand, if f1234 / f is above 8.000, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too weak, making it difficult to reduce the diameter of each lens in the front lens group and to achieve overall miniaturization of the wide-angle lens.

[0177] In contrast, in this embodiment, since condition 5 is satisfied, it has the advantages of making it easier to properly correct various aberrations and making it easier to achieve miniaturization.

[0178] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f567 of the fifth lens 150, the sixth lens 160, and the seventh lens 170 is 3.355 mm, and the overall focal distance f of the lens system is 1.011 mm. Therefore, condition 6 is satisfied:

[0179] 2.800 < f567 / f < 3.850

[0180] In condition 6, if f567 / f is below 2.800, the optical focal length of the rear lens group consisting of the fifth, sixth, and seventh lenses will be too strong, making it difficult to properly correct various aberrations, especially chromatic aberration. On the other hand, if f567 / f is above 3.850, it will be difficult to reduce the diameter of each lens and the distance between the object and the image, making it difficult to achieve the overall miniaturization of the wide-angle lens.

[0181] In contrast, in this embodiment, since condition 6 is satisfied, it has the advantages of being able to easily correct various aberrations, especially chromatic aberrations, and being easier to miniaturize.

[0182] Furthermore, in the wide-angle lens 1000, the object-image distance d is 13.404 mm, and the overall focal distance f of the lens system is 1.011 mm. Therefore, the following condition 7 is satisfied:

[0183] 11.000 < d / f < 15.000

[0184] In condition 7, if d / f is below 11.000, it is not easy to properly correct various aberrations. On the other hand, if d / f is above 15.000, the overall length of the lens system becomes too long.

[0185] In contrast, in this embodiment, since condition 7 is satisfied, it is easy to properly correct various aberrations, easily obtain excellent optical characteristics, and suppress the lens system from becoming too large while avoiding the overall length of the lens system becoming too long.

[0186] In summary, in this embodiment, by constructing the wide-angle lens 1000 in the manner described above, as follows... Figures 6A to 8L As shown, the positive optical power of the third lens can be avoided, thus making it easier to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can reduce the lens diameter and the distance between the object and the image, thus achieving overall miniaturization of the wide-angle lens. Moreover, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses and making it easier to achieve overall miniaturization of the wide-angle lens.

[0187] (Implementation Method 3)

[0188] Figure 9 This is an explanatory diagram showing the wide-angle lens according to Embodiment 3 of the present invention. Figure 10A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 3 of the present invention. Figure 10B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 3 of the present invention. Figure 11A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 3 of the present invention. Figure 11B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 3 of the present invention. Figures 12A to 12L This is an explanatory diagram illustrating the lateral aberration of the wide-angle lens according to Embodiment 3 of the present invention. Here, in Figure 10A , Figure 10B , Figure 11A , Figure 11B , Figures 12A to 12L In the diagram, the correlation curve for red light R (wavelength 656nm) is labeled R, the correlation curve for green light G (wavelength 588nm) is labeled G, and the correlation curve for blue light B (wavelength 486nm) is labeled B. T represents correlation with the meridional plane, and S represents correlation with the sagittal plane. Furthermore, in... Figures 12A to 12L In the figure, the maximum scale of the vertical axis is ±50.000 μm.

[0189] like Figure 9 As shown, the wide-angle lens 1000 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged sequentially from the object side (L1 side). The sixth lens 160 and the seventh lens 170 are bonded together with an adhesive to form a joint lens.

[0190] Since the basic structure of the wide-angle lens 1000 in this embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 have positive or negative optical power, whether they are glass lenses or plastic lenses, whether the object-side surface and the image-side surface are convex or concave, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in Embodiment 1, it will not be elaborated on here.

[0191] In addition, such as Figure 9 As shown, similar to Embodiment 1, a light-shielding sheet 190 is provided between the second lens 120 and the fourth lens 130, a filter 200 is provided on the image side of the seventh lens 170, and an image sensor 300 is provided on the image side of the filter 200.

[0192] In this embodiment, the overall focal length f (Effective Focal Length) of the lens system is 1.018 mm, the object-to-image distance d (Total Track) is 13.383 mm, the image space F / # is 2, the maximum field of view is 108 degrees, and the entrance pupil diameter HEP is 0.509 mm.

[0193] Table 5 shows the physical properties of each facet of the wide-angle lens 1000 of this embodiment, and Tables 6-1 and 6-2 show the aspherical coefficients of each facet of the wide-angle lens 1000 of this embodiment.

[0194] (Table 5)

[0195]

[0196] In Table 5 above, the units for radius of curvature, thickness, focal distance, and effective radius are mm, Nd is the refractive index of light at 587.56 nanometers, νd is the Abbe number, and * indicates an aspherical surface.

[0197] (Table 6-1)

[0198]

[0199] (Table 6-2)

[0200] noodle A8 A10 A12 A14 A16 3 -1.14938E-03 1.63223E-04 -7.82147E-06 0.00000E+00 0.00000E+00 4 5.61909E-02 -1.28652E-02 -3.10366E-04 0.00000E+00 0.00000E+00 5 2.71037E-03 -6.63668E-03 0.00000E+00 0.00000E+00 0.00000E+00 6 -3.16016E-03 -9.85165E-03 2.97746E-03 0.00000E+00 0.00000E+00 7 -1.96461E-02 8.38631E-03 0.00000E+00 0.00000E+00 0.00000E+00 8 -1.03312E-02 1.03923E-02 0.00000E+00 0.00000E+00 0.00000E+00 12 -8.59213E-03 1.81642E-02 -1.67818E-02 5.17215E-03 0.00000E+00 13 5.15225E-02 -2.02257E-02 1.88707E-03 3.30690E-04 0.00000E+00 14 4.12895E-02 -1.76625E-02 3.69776E-03 -2.59955E-04 0.00000E+00

[0201] In Tables 6-1 and 6-2 above, when the lens surface is a convex surface protruding towards the object side or a concave surface recessed towards the object side, the radius of curvature is set to a positive value; when the lens surface is a convex surface protruding towards the image side or a concave surface recessed towards the image side, the radius of curvature is set to a negative value.

[0202] Furthermore, Tables 6-1 and 6-2 above show the aspherical coefficients A4, A6, A8, A10, A12, A14, and A16 when each face has an aspherical shape, as represented by the mathematical formula 1 above.

[0203] Here, in the wide-angle lens 1000, the focal distance f3 of the third lens 130 is 9.374 mm, and the focal distance f of the entire lens system is 1.018 mm. Therefore, the following condition 1 is satisfied:

[0204] 3.000 < f3 / f < 12.500.

[0205] In condition 1, if f3 / f is less than 3.000, the positive optical focal length of the third lens is too large, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f3 / f is greater than 12.500, it is difficult to reduce the diameter of the third lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0206] In contrast, in this embodiment, since condition 1 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0207] In particular, in this embodiment, since the relationship 5.000 < f3 / f < 10.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0208] Furthermore, in the wide-angle lens 1000, the focal distance f4 of the fourth lens 140 is 4.796 mm, and the focal distance f of the entire lens system is 1.018 mm. Therefore, the following condition 2 is satisfied:

[0209] 4.000 < f4 / f < 7.000.

[0210] In condition 2, if f4 / f is below 4.000, the positive optical focal length of the fourth lens is too strong, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f4 / f is above 7.000, it is difficult to reduce the diameter of the fourth lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0211] In contrast, in this embodiment, since condition 2 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0212] In particular, in this embodiment, since the relationship 4.500 < f4 / f < 6.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0213] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -22.250 mm, and the focal distance f of the entire lens system is 1.018 mm. Therefore, the following condition 3 is satisfied:

[0214] 10.000 < |R41 / f| < 40.000.

[0215] In condition 3, if |R41 / f| is less than or equal to 10.000, the radius of curvature of the object-side lens surface of the fourth lens is small. When light reaching the image sensor is reflected off the surface of the image sensor and enters the fourth lens, the light is easily reflected off the object-side lens surface of the fourth lens and returns to the image sensor. As a result, ghosting is likely to occur. On the other hand, if |R41 / f| is greater than or equal to 40.000, the optical power of the fourth lens is small, and it is not easy to correct various aberrations.

[0216] In contrast, in this embodiment, since condition 3 is satisfied, it has the advantages of suppressing ghosting and easily and appropriately correcting various aberrations.

[0217] In particular, in this embodiment, since the relationship 13.000 < |R41 / f| < 30.000 is satisfied, it has the advantage of further suppressing the generation of ghosting and making it easier to properly correct various aberrations.

[0218] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -22.250 mm, and the focal distance f of the entire lens system is 1.018 mm. Therefore, the following condition 4 is satisfied:

[0219] -30.000 < R41 / f < -10.000.

[0220] In condition 4, if R41 / f is below -30.000, the negative optical power of the object-side lens surface of the fourth lens is small, making it difficult to properly correct various aberrations. On the other hand, if R41 / f is above -10.000, the radius of curvature of the object-side lens surface of the fourth lens is too small. When light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light is easily reflected at the object-side lens surface of the fourth lens and returns to the imaging element, which easily produces ghosting.

[0221] In contrast, in this embodiment, since condition 4 is satisfied, it has the advantage of being able to easily and appropriately correct various aberrations and suppress ghosting.

[0222] In particular, in this embodiment, since the relationship -25.000 < R41 / f < -12.000 is satisfied, it has the advantage of making it easier to properly correct various aberrations and further suppress ghosting.

[0223] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f1234 of the first lens 110, second lens 120, third lens 130, and fourth lens 140 is 4.528 mm, and the combined focal distance f567 of the fifth lens 150, sixth lens 160, and seventh lens 170 is 3.546 mm. Therefore, condition 5 is satisfied.

[0224] 0.800 < f1234 / f567 < 8.000.

[0225] In condition 5, if f1234 / f567 is below 0.800, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too strong, making it difficult to properly correct various aberrations. On the other hand, if f1234 / f is above 8.000, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too weak, making it difficult to reduce the diameter of each lens in the front lens group and to achieve overall miniaturization of the wide-angle lens.

[0226] In contrast, in this embodiment, since condition 5 is satisfied, it has the advantages of making it easier to properly correct various aberrations and making it easier to achieve miniaturization.

[0227] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f567 of the fifth lens 150, the sixth lens 160, and the seventh lens 170 is 3.546 mm, and the overall focal distance f of the lens system is 1.018 mm. Therefore, condition 6 is satisfied:

[0228] 2.800 < f567 / f < 3.850

[0229] In condition 6, if f567 / f is below 2.800, the optical focal length of the rear lens group consisting of the fifth, sixth, and seventh lenses will be too strong, making it difficult to properly correct various aberrations, especially chromatic aberration. On the other hand, if f567 / f is above 3.850, it will be difficult to reduce the diameter of each lens and the distance between the object and the image, making it difficult to achieve the overall miniaturization of the wide-angle lens.

[0230] In contrast, in this embodiment, since condition 6 is satisfied, it has the advantages of being able to easily correct various aberrations, especially chromatic aberrations, and being easier to miniaturize.

[0231] Furthermore, in the wide-angle lens 1000, the object-image distance d is 13.383 mm, and the overall focal distance f of the lens system is 1.018 mm. Therefore, the following condition 7 is satisfied:

[0232] 11.000 < d / f < 15.000

[0233] In condition 7, if d / f is below 11.000, it is not easy to properly correct various aberrations. On the other hand, if d / f is above 15.000, the overall length of the lens system becomes too long.

[0234] In contrast, in this embodiment, since condition 7 is satisfied, it is easy to properly correct various aberrations, easily obtain excellent optical characteristics, and suppress the lens system from becoming too large while avoiding the overall length of the lens system becoming too long.

[0235] In summary, in this embodiment, by constructing the wide-angle lens 1000 in the manner described above, as follows... Figures 10A to 12L As shown, the positive optical power of the third lens can be avoided, thus making it easier to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can reduce the lens diameter and the distance between the object and the image, thus achieving overall miniaturization of the wide-angle lens. Moreover, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses and making it easier to achieve overall miniaturization of the wide-angle lens.

[0236] (Implementation Method 4)

[0237] Figure 13 This is an explanatory diagram showing the wide-angle lens according to Embodiment 4 of the present invention. Figure 14A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 4 of the present invention. Figure 14B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 4 of the present invention. Figure 15A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 4 of the present invention. Figure 15B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 4 of the present invention. Figures 16A to 16L This is an explanatory diagram illustrating the lateral aberration of the wide-angle lens according to Embodiment 4 of the present invention. Here, in FIG14A, Figure 14B , Figure 15A , Figure 15B , Figures 16A to 16L In the diagram, the correlation curve for red light R (wavelength 656nm) is labeled R, the correlation curve for green light G (wavelength 588nm) is labeled G, and the correlation curve for blue light B (wavelength 486nm) is labeled B. T represents correlation with the meridional plane, and S represents correlation with the sagittal plane. Furthermore, in... Figures 16A to 16L In the figure, the maximum dimension of the vertical axis is ±50.000 μm.

[0238] like Figure 13As shown, the wide-angle lens 1000 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged sequentially from the object side (L1 side). The sixth lens 160 and the seventh lens 170 are bonded together with an adhesive to form a joint lens.

[0239] Since the basic structure of the wide-angle lens 1000 in this embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 have positive or negative optical power, whether they are glass lenses or plastic lenses, whether the object-side surface and the image-side surface are convex or concave, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in Embodiment 1, it will not be elaborated on here.

[0240] In addition, such as Figure 13 As shown, similar to Embodiment 1, a light-shielding sheet 190 is provided between the second lens 120 and the fourth lens 130, a filter 200 is provided on the image side of the seventh lens 170, and an image sensor 300 is provided on the image side of the filter 200.

[0241] In this embodiment, the overall focal length f (Effective Focal Length) of the lens system is 1.019 mm, the object-to-image distance d (Total Track) is 13.381 mm, the image space F / # is 2.0163, the maximum field of view is 108 degrees, and the entrance pupil diameter HEP is 0.505 mm.

[0242] Table 7 shows the physical properties of each facet of the wide-angle lens 1000 of this embodiment, and Tables 8-1 and 8-2 show the aspherical coefficients of each facet of the wide-angle lens 1000 of this embodiment.

[0243] (Table 7)

[0244]

[0245] In Table 7 above, the units for radius of curvature, thickness, focal distance, and effective radius are mm, Nd is the refractive index of light at 587.56 nanometers, νd is the Abbe number, and * indicates an aspherical surface.

[0246] (Table 8-1)

[0247]

[0248] (Table 8-2)

[0249] noodle A8 A10 A12 A14 A16 3 -1.15296E-03 1.63212E-04 -7.75247E-06 0.00000E+00 0.00000E+00 4 5.61909E-02 -1.28652E-02 -3.10366E-04 0.00000E+00 0.00000E+00 5 3.12004E-03 -6.74245E-03 0.00000E+00 0.00000E+00 0.00000E+00 6 -3.16016E-03 -9.85165E-03 2.97746E-03 0.00000E+00 0.00000E+00 7 -1.96461E-02 8.38631E-03 0.00000E+00 0.00000E+00 0.00000E+00 8 -1.03312E-02 1.03923E-02 0.00000E+00 0.00000E+00 0.00000E+00 12 -8.59213E-03 1.81642E-02 -1.67818E-02 5.17215E-03 0.00000E+00 13 5.15225E-02 -2.02257E-02 1.88707E-03 3.30690E-04 0.00000E+00 14 4.13120E-02 -1.76585E-02 3.69817E-03 -2.61279E-04 0.00000E+00

[0250] In Tables 8-1 and 8-2 above, when the lens surface is a convex surface protruding towards the object side or a concave surface recessed towards the object side, the radius of curvature is set to a positive value; when the lens surface is a convex surface protruding towards the image side or a concave surface recessed towards the image side, the radius of curvature is set to a negative value.

[0251] Furthermore, Tables 8-1 and 8-2 above show the aspherical coefficients A4, A6, A8, A10, A12, A14, and A16 when each face has an aspherical shape, as represented by the mathematical formula 1 above.

[0252] Here, in the wide-angle lens 1000, the focal distance f3 of the third lens 130 is 10.047 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 1 is satisfied:

[0253] 3.000 < f3 / f < 12.500.

[0254] In condition 1, if f3 / f is less than 3.000, the positive optical focal length of the third lens is too large, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f3 / f is greater than 12.500, it is difficult to reduce the diameter of the third lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0255] In contrast, in this embodiment, since condition 1 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0256] In particular, in this embodiment, since the relationship 5.000 < f3 / f < 10.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0257] Furthermore, in the wide-angle lens 1000, the focal distance f4 of the fourth lens 140 is 4.797 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 2 is satisfied:

[0258] 4.000 < f4 / f < 7.000.

[0259] In condition 2, if f4 / f is below 4.000, the positive optical focal length of the fourth lens is too strong, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f4 / f is above 7.000, it is difficult to reduce the diameter of the fourth lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0260] In contrast, in this embodiment, since condition 2 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0261] In particular, in this embodiment, since the relationship 4.500 < f4 / f < 6.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0262] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -22.250 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 3 is satisfied:

[0263] 10.000 < |R41 / f| < 40.000.

[0264] In condition 3, if |R41 / f| is less than or equal to 10.000, the radius of curvature of the object-side lens surface of the fourth lens is small. When light reaching the image sensor is reflected off the surface of the image sensor and enters the fourth lens, the light is easily reflected off the object-side lens surface of the fourth lens and returns to the image sensor. As a result, ghosting is likely to occur. On the other hand, if |R41 / f| is greater than or equal to 40.000, the optical power of the fourth lens is small, and it is not easy to correct various aberrations.

[0265] In contrast, in this embodiment, since condition 3 is satisfied, it has the advantages of suppressing ghosting and easily and appropriately correcting various aberrations.

[0266] In particular, in this embodiment, since the relationship 13.000 < |R41 / f| < 30.000 is satisfied, it has the advantage of further suppressing the generation of ghosting and making it easier to properly correct various aberrations.

[0267] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -22.250 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 4 is satisfied:

[0268] -30.000 < R41 / f < -10.000.

[0269] In condition 4, if R41 / f is below -30.000, the negative optical power of the object-side lens surface of the fourth lens is small, making it difficult to properly correct various aberrations. On the other hand, if R41 / f is above -10.000, the radius of curvature of the object-side lens surface of the fourth lens is too small. When light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light is easily reflected at the object-side lens surface of the fourth lens and returns to the imaging element, which easily produces ghosting.

[0270] In contrast, in this embodiment, since condition 4 is satisfied, it has the advantage of being able to easily and appropriately correct various aberrations and suppress ghosting.

[0271] In particular, in this embodiment, since the relationship -25.000 < R41 / f < -12.000 is satisfied, it has the advantage of making it easier to properly correct various aberrations and further suppress ghosting.

[0272] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f1234 of the first lens 110, second lens 120, third lens 130, and fourth lens 140 is 4.815 mm, and the combined focal distance f567 of the fifth lens 150, sixth lens 160, and seventh lens 170 is 3.557 mm. Therefore, condition 5 is satisfied.

[0273] 0.800 < f1234 / f567 < 8.000.

[0274] In condition 5, if f1234 / f567 is below 0.800, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too strong, making it difficult to properly correct various aberrations. On the other hand, if f1234 / f is above 8.000, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too weak, making it difficult to reduce the diameter of each lens in the front lens group and to achieve overall miniaturization of the wide-angle lens.

[0275] In contrast, in this embodiment, since condition 5 is satisfied, it has the advantages of making it easier to properly correct various aberrations and making it easier to achieve miniaturization.

[0276] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f567 of the fifth lens 150, the sixth lens 160, and the seventh lens 170 is 3.557 mm, and the overall focal distance f of the lens system is 1.019 mm. Therefore, the following condition 6 is satisfied:

[0277] 2.800 < f567 / f < 3.850

[0278] In condition 6, if f567 / f is below 2.800, the optical focal length of the rear lens group consisting of the fifth, sixth, and seventh lenses will be too strong, making it difficult to properly correct various aberrations, especially chromatic aberration. On the other hand, if f567 / f is above 3.850, it will be difficult to reduce the diameter of each lens and the distance between the object and the image, making it difficult to achieve the overall miniaturization of the wide-angle lens.

[0279] In contrast, in this embodiment, since condition 6 is satisfied, it has the advantages of being able to easily correct various aberrations, especially chromatic aberrations, and being easier to miniaturize.

[0280] Furthermore, in the wide-angle lens 1000, the object-image distance d is 13.381 mm, and the overall focal distance f of the lens system is 1.019 mm. Therefore, the following condition 7 is satisfied:

[0281] 11.000 < d / f < 15.000

[0282] In condition 7, if d / f is below 11.000, it is not easy to properly correct various aberrations. On the other hand, if d / f is above 15.000, the overall length of the lens system becomes too long.

[0283] In contrast, in this embodiment, since condition 7 is satisfied, it is easy to properly correct various aberrations, easily obtain excellent optical characteristics, and suppress the lens system from becoming too large while avoiding the overall length of the lens system becoming too long.

[0284] In summary, in this embodiment, by constructing the wide-angle lens 1000 in the manner described above, as follows... Figures 14A to 16LAs shown, the positive optical power of the third lens can be avoided, thus making it easier to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can reduce the lens diameter and the distance between the object and the image, thus achieving overall miniaturization of the wide-angle lens. Moreover, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses and making it easier to achieve overall miniaturization of the wide-angle lens.

[0285] (Implementation Method 5)

[0286] Figure 17 This is an explanatory diagram showing the wide-angle lens according to Embodiment 5 of the present invention. Figure 18A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 5 of the present invention. Figure 18B This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 5 of the present invention. Figure 19A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 5 of the present invention. Figure 19B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 5 of the present invention. Figures 20A to 20L This is an explanatory diagram illustrating the lateral aberration of the wide-angle lens according to Embodiment 5 of the present invention. Here, in FIG18A, Figure 18B , Figure 19A , Figure 19B , Figures 20A to 20L In the diagram, the correlation curve for red light R (wavelength 656nm) is labeled R, the correlation curve for green light G (wavelength 588nm) is labeled G, and the correlation curve for blue light B (wavelength 486nm) is labeled B. T represents correlation with the meridional plane, and S represents correlation with the sagittal plane. Furthermore, in... Figures 20A to 20L In the figure, the maximum dimension of the vertical axis is ±50.000 μm.

[0287] like Figure 17 As shown, the wide-angle lens 1000 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged sequentially from the object side (L1 side). The sixth lens 160 and the seventh lens 170 are bonded together with an adhesive to form a joint lens.

[0288] Since the basic structure of the wide-angle lens 1000 in this embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 have positive or negative optical power, whether they are glass lenses or plastic lenses, whether the object-side surface and the image-side surface are convex or concave, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in Embodiment 1, it will not be elaborated on here.

[0289] In addition, such as Figure 17 As shown, similar to Embodiment 1, a light-shielding sheet 190 is provided between the second lens 120 and the fourth lens 130, a filter 200 is provided on the image side of the seventh lens 170, and an image sensor 300 is provided on the image side of the filter 200.

[0290] In this embodiment, the overall focal length f (Effective Focal Length) of the lens system is 1.030 mm, the object-to-image distance d (Total Track) is 13.609 mm, the image space F / # is 2, the maximum field of view is 106 degrees, and the entrance pupil diameter HEP is 0.515 mm.

[0291] Table 9 shows the physical properties of each facet of the wide-angle lens 1000 of this embodiment, and Tables 10-1 and 10-2 show the aspherical coefficients of each facet of the wide-angle lens 1000 of this embodiment.

[0292] (Table 9)

[0293]

[0294] In Table 9 above, the units for radius of curvature, thickness, focal distance, and effective radius are mm, Nd is the refractive index of light at 587.56 nanometers, νd is the Abbe number, and * indicates an aspherical surface.

[0295] (Table 10-1)

[0296] noodle c(1 / radius of curvature) K A4 A6 3 -4.38390E-02 0.00000E+00 1.02948E-02 -1.01140E-03 4 7.88668E-01 -1.13571E+00 5.66499E-02 1.84231E-03 5 2.82343E-01 0.00000E+00 -2.18543E-02 5.16357E-03 6 1.17050E-01 0.00000E+00 -6.48711E-02 -8.41810E-03 7 2.24418E-01 0.00000E+00 3.04785E-02 1.99197E-02 8 -1.03429E-01 0.00000E+00 9.05286E-02 3.48783E-02 12 -1.83670E-01 0.00000E+00 -3.32106E-02 4.95833E-02 13 9.17180E-01 -3.67711E+00 1.58393E-01 -3.03404E-02 14 -5.07238E-01 -6.42125E-01 3.25791E-02 -8.99922E-03

[0297] (Table 10-2)

[0298]

[0299]

[0300] In Tables 10-1 and 10-2 above, when the lens surface is a convex surface protruding towards the object side or a concave surface recessed towards the object side, the radius of curvature is set to a positive value; when the lens surface is a convex surface protruding towards the image side or a concave surface recessed towards the image side, the radius of curvature is set to a negative value.

[0301] Furthermore, Tables 10-1 and 10-2 above show the aspherical coefficients A4, A6, A8, A10, A12, A14, and A16 when the aspherical shape of each face is represented by the mathematical formula 1 above.

[0302] Here, in the wide-angle lens 1000, the focal distance f3 of the third lens 130 is 10.255 mm, and the focal distance f of the entire lens system is 1.030 mm. Therefore, the following condition 1 is satisfied:

[0303] 3.000 < f3 / f < 12.500.

[0304] In condition 1, if f3 / f is less than 3.000, the positive optical focal length of the third lens is too large, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f3 / f is greater than 12.500, it is difficult to reduce the diameter of the third lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0305] In contrast, in this embodiment, since condition 1 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0306] In particular, in this embodiment, since the relationship 5.000 < f3 / f < 10.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0307] Furthermore, in the wide-angle lens 1000, the focal distance f4 of the fourth lens 140 is 4.851 mm, and the focal distance f of the entire lens system is 1.030 mm. Therefore, the following condition 2 is satisfied:

[0308] 4.000 < f4 / f < 7.000.

[0309] In condition 2, if f4 / f is below 4.000, the positive optical focal length of the fourth lens is too strong, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f4 / f is above 7.000, it is difficult to reduce the diameter of the fourth lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0310] In contrast, in this embodiment, since condition 2 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0311] In particular, in this embodiment, since the relationship 4.500 < f4 / f < 6.000 is satisfied, it has the advantages of making it easier to properly correct various aberrations such as field curvature, chromatic aberration, and coma, and making it easier to achieve overall miniaturization of the wide-angle lens.

[0312] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f1234 of the first lens 110, second lens 120, third lens 130, and fourth lens 140 is 21.864 mm, and the combined focal distance f567 of the fifth lens 150, sixth lens 160, and seventh lens 170 is 3.125 mm. Therefore, condition 5 is satisfied.

[0313] 0.800 < f1234 / f567 < 8.000.

[0314] In condition 5, if f1234 / f567 is below 0.800, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too strong, making it difficult to properly correct various aberrations. On the other hand, if f1234 / f is above 8.000, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too weak, making it difficult to reduce the diameter of each lens in the front lens group and to achieve overall miniaturization of the wide-angle lens.

[0315] In contrast, in this embodiment, since condition 5 is satisfied, it has the advantages of making it easier to properly correct various aberrations and making it easier to achieve miniaturization.

[0316] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f567 of the fifth lens 150, the sixth lens 160, and the seventh lens 170 is 3.125 mm, and the overall focal distance f of the lens system is 1.030 mm. Therefore, the following condition 6 is satisfied:

[0317] 2.800 < f567 / f < 3.850

[0318] In condition 6, if f567 / f is below 2.800, the optical focal length of the rear lens group consisting of the fifth, sixth, and seventh lenses will be too strong, making it difficult to properly correct various aberrations, especially chromatic aberration. On the other hand, if f567 / f is above 3.850, it will be difficult to reduce the diameter of each lens and the distance between the object and the image, making it difficult to achieve the overall miniaturization of the wide-angle lens.

[0319] In contrast, in this embodiment, since condition 6 is satisfied, it has the advantages of being able to easily correct various aberrations, especially chromatic aberrations, and being easier to miniaturize.

[0320] Furthermore, in the wide-angle lens 1000, the object-image distance d is 13.609 mm, and the overall focal distance f of the lens system is 1.030 mm. Therefore, the following condition 7 is satisfied:

[0321] 11.000 < d / f < 15.000

[0322] In condition 7, if d / f is below 11.000, it is not easy to properly correct various aberrations. On the other hand, if d / f is above 15.000, the overall length of the lens system becomes too long.

[0323] In contrast, in this embodiment, since condition 7 is satisfied, it is easy to properly correct various aberrations, easily obtain excellent optical characteristics, and suppress the lens system from becoming too large while avoiding the overall length of the lens system becoming too long.

[0324] In summary, in this embodiment, by constructing the wide-angle lens 1000 in the manner described above, as follows... Figures 18A to 20L As shown, the positive optical power of the third lens can be avoided, thus making it easier to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can reduce the lens diameter and the distance between the object and the image, thus achieving overall miniaturization of the wide-angle lens. Moreover, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses and making it easier to achieve overall miniaturization of the wide-angle lens.

[0325] (Implementation Method 6)

[0326] Figure 21 This is an explanatory diagram showing the wide-angle lens according to Embodiment 6 of the present invention. Figure 22A This is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 6 of the present invention. Figure 22BThis is an explanatory diagram showing the field curvature and distortion of the wide-angle lens according to Embodiment 6 of the present invention. Figure 23A This is an explanatory diagram showing the transverse chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to Embodiment 6 of the present invention. Figure 23B This is an explanatory diagram showing the spherical aberration (longitudinal aberration) of the wide-angle lens according to Embodiment 6 of the present invention. Figures 24A to 24L This is an explanatory diagram showing the lateral aberration of the wide-angle lens according to Embodiment 9 of the present invention. Here, in FIG22A, Figure 22B , Figure 23A , Figure 23B , Figures 24A to 24L In the diagram, the correlation curve for red light R (wavelength 656nm) is labeled R, the correlation curve for green light G (wavelength 588nm) is labeled G, and the correlation curve for blue light B (wavelength 486nm) is labeled B. T represents correlation with the meridional plane, and S represents correlation with the sagittal plane. Furthermore, in... Figures 24A to 24L In the figure, the maximum scale of the vertical axis is ±50.000 μm.

[0327] like Figure 21 As shown, the wide-angle lens 1000 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, an aperture 180, a fifth lens 150, a sixth lens 160, and a seventh lens 170 arranged sequentially from the object side (L1 side). The sixth lens 160 and the seventh lens 170 are bonded together with an adhesive to form a joint lens.

[0328] Since the basic structure of the wide-angle lens 1000 in this embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 have positive or negative optical power, whether they are glass lenses or plastic lenses, whether the object-side surface and the image-side surface are convex or concave, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in Embodiment 1, it will not be elaborated on here.

[0329] In addition, such as Figure 21 As shown, similar to Embodiment 1, a light-shielding sheet 190 is provided between the second lens 120 and the fourth lens 130, a filter 200 is provided on the image side of the seventh lens 170, and an image sensor 300 is provided on the image side of the filter 200.

[0330] In this embodiment, the overall focal length f (Effective Focal Length) of the lens system is 1.019 mm, the object-to-image distance d (Total Track) is 13.397 mm, the image space F / # is 2.012, the maximum field of view is 108.004 degrees, and the entrance pupil diameter HEP is 0.506 mm.

[0331] Table 11 shows the physical properties of each facet of the wide-angle lens 1000 of this embodiment, and Tables 12-1 and 12-2 show the aspherical coefficients of each facet of the wide-angle lens 1000 of this embodiment.

[0332] (Table 11)

[0333]

[0334] In Table 11 above, the units for radius of curvature, thickness, focal distance, and effective radius are mm, Nd is the refractive index of light at 587.56 nanometers, νd is the Abbe number, and * indicates an aspherical surface.

[0335] (Table 12-1)

[0336]

[0337] (Table 12-2)

[0338] noodle A8 A10 A12 A14 A16 3 -6.11588E-05 1.50045E-05 3.90615E-08 0.00000E+00 0.00000E+00 4 4.96308E-02 -1.37651E-02 1.87863E-04 0.00000E+00 0.00000E+00 5 2.50539E-03 -1.94316E-04 -2.18386E-04 0.00000E+00 0.00000E+00 6 2.37631E-03 4.68175E-04 1.19525E-03 0.00000E+00 0.00000E+00 7 1.14133E-02 6.53638E-04 0.00000E+00 0.00000E+00 0.00000E+00 8 1.36753E-02 -1.98505E-03 0.00000E+00 0.00000E+00 0.00000E+00 12 3.38366E-03 -2.00010E-03 6.86525E-04 0.00000E+00 0.00000E+00 13 2.79270E-02 -5.22149E-03 -1.20343E-04 0.00000E+00 0.00000E+00 14 2.26165E-02 -7.19858E-03 9.87041E-04 0.00000E+00 0.00000E+00

[0339] In Tables 12-1 and 12-2 above, when the lens surface is a convex surface protruding towards the object side or a concave surface recessed towards the object side, the radius of curvature is set to a positive value; when the lens surface is a convex surface protruding towards the image side or a concave surface recessed towards the image side, the radius of curvature is set to a negative value.

[0340] Furthermore, Tables 12-1 and 12-2 above show the aspherical coefficients A4, A6, A8, A10, A12, A14, and A16 when each face has an aspherical shape, as represented by the mathematical formula 1 above.

[0341] Here, in the wide-angle lens 1000, the focal distance f3 of the third lens 130 is 12.527 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 1 is satisfied:

[0342] 3.000 < f3 / f < 12.500.

[0343] In condition 1, if f3 / f is less than 3.000, the positive optical focal length of the third lens is too large, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f3 / f is greater than 12.500, it is difficult to reduce the diameter of the third lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0344] In contrast, in this embodiment, since condition 1 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0345] Furthermore, in the wide-angle lens 1000, the focal distance f4 of the fourth lens 140 is 6.634 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 2 is satisfied:

[0346] 4.000 < f4 / f < 7.000.

[0347] In condition 2, if f4 / f is below 4.000, the positive optical focal length of the fourth lens is too strong, making it difficult to properly correct various aberrations such as field curvature, magnification chromatic aberration, and coma. On the other hand, if f4 / f is above 7.000, it is difficult to reduce the diameter of the fourth lens and the distance between the object and the image, making it difficult to achieve overall miniaturization of the wide-angle lens.

[0348] In contrast, in this embodiment, since condition 2 is satisfied, it has the advantages of easily and appropriately correcting various aberrations such as field curvature, magnification chromatic aberration, and coma, and easily achieving the miniaturization of the wide-angle lens as a whole.

[0349] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -12.641 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 3 is satisfied:

[0350] 10.000 < |R41 / f| < 40.000.

[0351] In condition 3, if |R41 / f| is less than or equal to 10.000, the radius of curvature of the object-side lens surface of the fourth lens is small. When light reaching the image sensor is reflected off the surface of the image sensor and enters the fourth lens, the light is easily reflected off the object-side lens surface of the fourth lens and returns to the image sensor. As a result, ghosting is likely to occur. On the other hand, if |R41 / f| is greater than or equal to 40.000, the optical power of the fourth lens is small, and it is not easy to correct various aberrations.

[0352] In contrast, in this embodiment, since condition 3 is satisfied, it has the advantages of being able to suppress the generation of ghosting and easily and appropriately correct various aberrations.

[0353] In particular, in this embodiment, since the relationship 13.000 < |R41 / f| < 30.000 is satisfied, it has the advantage of further suppressing the generation of ghosting and making it easier to properly correct various aberrations.

[0354] Furthermore, in the wide-angle lens 1000, the radius of curvature R41 of the object-side lens surface (i.e., surface 7) of the fourth lens 140 is -12.641 mm, and the focal distance f of the entire lens system is 1.019 mm. Therefore, the following condition 4 is satisfied:

[0355] -30.000 < R41 / f < -10.000.

[0356] In condition 4, if R41 / f is below -30.000, the negative optical power of the object-side lens surface of the fourth lens is small, making it difficult to properly correct various aberrations. On the other hand, if R41 / f is above -10.000, the radius of curvature of the object-side lens surface of the fourth lens is too small. When light reaching the imaging element is reflected on the surface of the imaging element and enters the fourth lens, the light is easily reflected at the object-side lens surface of the fourth lens and returns to the imaging element, which easily produces ghosting.

[0357] In contrast, in this embodiment, since condition 4 is satisfied, it has the advantage of being able to easily and appropriately correct various aberrations and suppress ghosting.

[0358] In particular, in this embodiment, since the relationship -25.000 < R41 / f < -12.000 is satisfied, it has the advantage of making it easier to properly correct various aberrations and further suppress ghosting.

[0359] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f1234 of the first lens 110, second lens 120, third lens 130, and fourth lens 140 is 26.363 mm, and the combined focal distance f567 of the fifth lens 150, sixth lens 160, and seventh lens 170 is 3.374 mm. Therefore, condition 5 is satisfied.

[0360] 0.800 < f1234 / f567 < 8.000.

[0361] In condition 5, if f1234 / f567 is below 0.800, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too strong, making it difficult to properly correct various aberrations. On the other hand, if f1234 / f is above 8.000, the optical focal length of the front lens group consisting of the first, second, third, and fourth lenses is too weak, making it difficult to reduce the diameter of each lens in the front lens group and to achieve overall miniaturization of the wide-angle lens.

[0362] In contrast, in this embodiment, since condition 5 is satisfied, it has the advantages of making it easier to properly correct various aberrations and making it easier to achieve miniaturization.

[0363] Furthermore, in the wide-angle lens 1000, the third lens 130 is a positive lens with its convex surface facing the image side, the fourth lens 140 is a positive lens with its convex surface facing the image side, the fifth lens 150 is a positive lens with its convex surface facing both the object and image sides, the sixth lens 160 is a negative lens with its concave surface facing the image side, and the seventh lens 170 is a positive lens with its convex surface facing both the object and image sides. The combined focal distance f567 of the fifth lens 150, the sixth lens 160, and the seventh lens 170 is 3.374 mm, and the overall focal distance f of the lens system is 1.019 mm. Therefore, condition 6 is satisfied:

[0364] 2.800 < f567 / f < 3.850

[0365] In condition 6, if f567 / f is below 2.800, the optical focal length of the rear lens group consisting of the fifth, sixth, and seventh lenses will be too strong, making it difficult to properly correct various aberrations, especially chromatic aberration. On the other hand, if f567 / f is above 3.850, it will be difficult to reduce the diameter of each lens and the distance between the object and the image, making it difficult to achieve the overall miniaturization of the wide-angle lens.

[0366] In contrast, in this embodiment, since condition 6 is satisfied, it has the advantages of being able to easily correct various aberrations, especially chromatic aberrations, and being easier to miniaturize.

[0367] Furthermore, in the wide-angle lens 1000, the object-image distance d is 13.397 mm, and the overall focal distance f of the lens system is 1.019 mm. Therefore, the following condition 7 is satisfied:

[0368] 11.000 < d / f < 15.000

[0369] In condition 7, if d / f is below 11.000, it is not easy to properly correct various aberrations. On the other hand, if d / f is above 15.000, the overall length of the lens system becomes too long.

[0370] In contrast, in this embodiment, since condition 7 is satisfied, it is easy to properly correct various aberrations, easily obtain excellent optical characteristics, and suppress the lens system from becoming too large while avoiding the overall length of the lens system becoming too long.

[0371] In summary, in this embodiment, by constructing the wide-angle lens 1000 in the manner described above, as follows... Figures 22A to 24L As shown, the positive optical power of the third lens can be avoided, thus making it easier to appropriately correct various aberrations such as field curvature, chromatic aberration, and coma, thereby achieving excellent optical characteristics. Furthermore, it can reduce the lens diameter and the distance between the object and the image, thus achieving overall miniaturization of the wide-angle lens. Moreover, since both the third and fourth lenses are positive lenses, the negative optical power of the first and second lenses can be enhanced, thereby reducing the diameter of the first and second lenses and making it easier to achieve overall miniaturization of the wide-angle lens.

[0372] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above embodiments.

[0373] For example, in the above embodiments, the shape of the first surface 1 of the first lens 110, the shape of the third surface 3 of the second lens 120, the shape of the fifth surface 5 of the third lens 130, the shape of the seventh surface 7 of the fourth lens 140, and the shape of the twelfth surface 12 of the sixth lens 160 can be appropriately changed as needed.

[0374] Furthermore, in the above embodiments, the first lens 110 and the fifth lens 150 may also be made of plastic lenses, and the second lens 120, the third lens 130, the fourth lens 140, the sixth lens 160 and the seventh lens 170 may also be made of glass lenses.

Claims

1. A wide-angle lens, characterized in that, The number of lenses with optical power is seven, including a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side. The first lens is a negative lens with a concave image-side lens surface. The second lens is a negative lens with a concave image-side lens surface. The third lens is a positive lens with a convex image-side lens surface. The fourth lens is a positive lens with a convex image-side lens surface. The fifth lens is a positive lens. The sixth lens is a negative lens. The seventh lens is a positive lens. When the focal distance of the third lens is set to f3 and the focal distance of the entire wide-angle lens is set to f, the following relationship is satisfied: 3.000 < f3 / f < 12.500 The fourth lens is a positive lens with a concave object-side lens surface and a convex image-side lens surface. When the radius of curvature of the object-side lens surface of the fourth lens is set to R41, the following relationship is satisfied: -30.000 < R41 / f < -10.000 When the focal distance of the fourth lens is set to f4, the following relationship is satisfied: 4.000 < f4 / f < 7.

000.

2. The wide-angle lens as described in claim 1, characterized in that, The following relationship must be satisfied: 5.000 < f3 / f < 10.

000.

3. The wide-angle lens as described in claim 1, characterized in that, The following relationship must be satisfied: 4.500 < f4 / f < 6.

000.

4. The wide-angle lens as described in any one of claims 1 to 3, characterized in that, The following relationship must be satisfied: 13.000 < |R41 / f| < 30.

000.

5. The wide-angle lens as described in any one of claims 1 to 3, characterized in that, The following relationship must be satisfied: -25.000 < R41 / f < -12.

000.

6. The wide-angle lens as described in claim 1, characterized in that, The first lens and the fifth lens are both glass lenses. The second lens, the third lens, the fourth lens, the sixth lens, and the seventh lens are all plastic lenses.

Images