JP7269801B2 - wide angle lens - Google Patents

Description

The present invention relates to wide-angle lenses used in various imaging systems.

In a wide-angle lens, a lens configuration of 5 groups and 6 lenses has been proposed in order to obtain high resolution (see Patent Document 1). In the wide-angle lens disclosed in Patent Document 1, a front group, a diaphragm, and a rear group are arranged in order from the object side to the image side. A lens and a second lens are arranged in order. The first lens is a negative meniscus lens whose image-side lens surface is a concave surface, and the second lens is a negative meniscus lens whose image-side lens surface is a concave surface. A wide-angle lens described in Patent Document 1 and the like is used in a sensor device for automobiles.

JP 2016-57562 A

However, in the wide-angle lens described in Patent Document 1 and the like, the image-side concave lens surface of the second lens and the object-side concave lens surface of the third lens are separated between the second lens and the third lens. facing each other. For this reason, multiple reflections tend to occur between the lens surface of the second lens and the object-side lens surface of the third lens, and ring-shaped ghosts tend to occur due to such multiple reflections.

In view of the above problems, an object of the present invention is to suppress the occurrence of ghosts caused by multiple reflections between the image-side lens surface of the second lens and the object-side lens surface of the third lens. To provide a wide-angle lens capable of

In order to solve the above problems, a wide-angle lens according to the present invention has a front group, a diaphragm, and a rear group arranged in order from the object side to the image side. a first lens, a second lens and a third lens are arranged in order, and in the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side, and The first lens is a negative meniscus lens whose image-side lens surface is a concave surface, the second lens is a negative lens whose image-side lens surface is a concave surface, and the third lens is an object-side lens. and the fourth lens is a biconvex lens in which both the lens surface on the object side and the lens surface on the image side are convex surfaces. wherein the fifth lens is a negative lens whose image-side lens surface is a concave surface; and the sixth lens is a biconvex lens whose object-side lens surface and image-side lens surface are convex surfaces; The fifth lens and the sixth lens are cemented lenses in which the image-side lens surface of the fifth lens and the object-side lens surface of the sixth lens are cemented together, and the object-side lens surface of the third lens is cemented. Sag31 (mm) is the sag amount of the lens surface, and D31 (mm) is the diameter of the object-side lens surface of the third lens. (D31/2)|<0.060
is characterized by satisfying

In the present invention, the object-side lens surface of the third lens is a convex curved surface, so that an imaging area can be secured. In addition, since the fourth lens having positive power is arranged behind the diaphragm, it is possible to correct various aberrations even at a wide angle. In addition, since the fourth lens having positive power is arranged behind the diaphragm, the angle of incidence on the imaging plane can be kept small. Therefore, it is possible to correspond to an imaging element with a large number of pixels. Furthermore, since the fifth group is a cemented lens of the double concave fifth lens and the double convex sixth lens, it is advantageous for correction of lateral chromatic aberration. Therefore, it is possible to suppress the occurrence of chromatic aberration of magnification that accompanies the widening of the angle of view. Also, the absolute value of the ratio (Sag31/(D31/2)) between the sag amount Sag31 of the object-side lens surface of the third lens and the radius (D31/2) of the object-side lens surface of the third lens is the lower limit ( 0), the object-side lens surface of the third lens is not flat. Therefore, various aberrations can be properly corrected. In addition, since the upper limit (0.060) is set for the absolute value of the ratio (Sag31/(D31/2)), a concave surface with a large amount of sag and a convex surface with a large amount of sag are formed between the second lens and the third lens. can be avoided from facing each other. Therefore, multiple reflection between the image-side lens surface of the second lens and the object-side lens surface of the third lens can be suppressed. Therefore, it is possible to suppress the occurrence of a ring-shaped ghost due to multiple reflection between the image-side lens surface of the second lens and the object-side lens surface of the third lens.

In the present invention, when the central thickness of the first lens in the optical axis direction is T1 (mm) and the focal length of the entire lens system is f0 (mm), the following conditional expression: 1.500≤T1/f0≤1. 850
is characterized by satisfying In this aspect, the ratio (T1/f0) of the central thickness of the first lens in the optical axis direction, T1, and the focal length of the entire lens system, f0, exceeds the lower limit (1.500). thicken. Therefore, it is possible to prevent the first lens from being damaged by an impact. Moreover, since the upper limit (1.500) is set for the ratio (T1/f0), it is possible to prevent the first lens from becoming too thick. Therefore, it is possible to prevent the first lens from becoming too thick and failing to obtain a suitable negative power.

In the present invention, when the focal length of the entire lens system is f0 (mm) and the focal length of the first lens is f1 (mm), the following conditional expression −6.000<f1/f0<−4. 500
It is desirable to satisfy In this aspect, since the ratio (f1/f0) between the focal length f0 of the entire lens system and the focal length f1 of the first lens exceeds the lower limit (-6.000), the wide-angle lens is made wider and smaller. be able to. In addition, since the ratio (f1/f0) of the focal length f0 of the entire lens system and the focal length f1 of the first lens has an upper limit (-4.500), the refractive power of the first lens is appropriate. Aberration can be properly corrected.

In the present invention, when the focal length of the first lens is f1 (mm) and the focal length of the second lens is f2 (mm), the following conditional expression: 2.000<f1/f2<2.400
It is desirable to satisfy In this aspect, since the ratio (f1/f2) of the focal length f1 of the first lens to the focal length f2 of the second lens exceeds the lower limit (2.000), the wide angle lens can be widened. Moreover, since the ratio (f1/f2) of the focal length f1 of the first lens and the focal length f2 of the second lens has an upper limit (2.400), distortion can be properly corrected.

In the present invention, when the focal length of the entire lens system is f0 (mm) and the focal length of the third lens is f3 (mm), the following conditional expression: 3.500<f3/f0<5.000
It is desirable to satisfy In this aspect, since the ratio (f3/f0) between the focal length f0 of the entire lens system and the focal length f3 of the third lens exceeds the lower limit (3.500), the power of the third lens is prevented from becoming too strong. be able to. Therefore, various aberrations can be properly corrected. In addition, since the ratio (f3/f0) of the focal length f0 of the entire lens system and the focal length f3 of the third lens has an upper limit (5.000), the lens diameter and the distance between objects of the entire lens system can be reduced. can. Therefore, the wide-angle lens can be miniaturized.

In the present invention, when the focal length of the entire lens system is f0 (mm) and the focal length of the second lens is f2 (mm), the following conditional expression −2.800<f2/f0<−2. 100
It is desirable to satisfy In this aspect, the ratio (f2/f0) between the focal length f0 of the entire lens system and the focal length f2 of the second lens exceeds the lower limit (−2.800), so the lens diameter and the inter-object distance of the entire lens system can be reduced. can do. Therefore, the wide-angle lens can be miniaturized. Also, since the ratio (f2/f0) of the focal length f0 of the entire lens system and the focal length f2 of the second lens has an upper limit (-2.100), it is possible to avoid the power of the second lens from becoming too strong. can be done. Therefore, an imaging area can be secured and various aberrations can be corrected appropriately.

In the present invention, when the focal length of the entire lens system is f0 (mm) and the focal length of the fourth lens is f4 (mm), the following conditional expression: 2.800<f4/f0<4.000
It is desirable to satisfy In this aspect, since the ratio (f4/f0) between the focal length f0 of the entire lens system and the focal length f4 of the fourth lens exceeds the lower limit (2.800), it is possible to avoid the power of the fourth lens from becoming too strong. can do. Therefore, various aberrations can be properly corrected. In addition, since the ratio (f4/f0) of the focal length f0 of the entire lens system and the focal length f4 of the fourth lens has an upper limit (4.000), the lens diameter and the inter-object distance of the entire lens system can be reduced. can be done. Therefore, the wide-angle lens can be miniaturized.

In the present invention, when the focal length of the entire lens system is f0 (mm) and the combined focal length of the fourth lens, the fifth lens and the sixth lens is f456 (mm), the following conditional expression 2 .000<f456/f0<3.000
It is desirable to satisfy In this aspect, the ratio (f456/f0) between the focal length f0 of the entire lens system and the combined focal length f456 of the fourth, fifth and sixth lenses exceeds the lower limit (2.000). It is possible to avoid that the power of becomes too strong. Therefore, various aberrations can be properly corrected. Therefore, high optical characteristics can be realized. In addition, since the ratio (f456/f0) between the focal length f0 of the entire lens system and the combined focal length f456 of the fourth, fifth and sixth lenses (f456/f0) has an upper limit (3.000), the power of the rear group can be avoided from becoming too weak. Therefore, the wide-angle lens can be miniaturized.

In the present invention, when the focal length of the entire lens system is f0 (mm) and the combined focal length of the fifth lens and the sixth lens is f56 (mm), the following conditional expression: 5.000<f56/ f<7.000
It is desirable to satisfy In this aspect, the ratio (f56/f0) between the focal length f0 of the entire lens system and the combined focal length f56 of the fifth lens and the sixth lens is within the range of the condition, so that chromatic aberration is corrected appropriately. be able to.

In the present invention, the following conditional expression −5.000<R42/f0<-2.800
It is desirable to satisfy In this aspect, the ratio (R42/f0) between the focal length f0 of the entire lens system and the radius of curvature R42 on the optical axis of the image-side lens surface of the fourth lens is at the lower limit (-5.
000), various aberrations can be corrected appropriately. In addition, since the ratio (R42/f0) between the focal length f0 of the entire lens system and the curvature radius R42 on the optical axis of the image-side lens surface of the fourth lens has an upper limit (-2.800), the fourth lens It is possible to prevent the radius of curvature of the image-side lens surface on the optical axis from becoming too small. Therefore, it is possible to mold the image-side lens surface of the fourth lens.

In the present invention, the following conditional expression: 10.000<d0/f0<18.000 where d0 is the object-to-image distance of the entire lens system and f0 is the focal length of the entire lens system.
It is desirable to satisfy In this aspect, since the ratio (d0/f0) between the object-to-image distance d0 of the entire lens system and the focal length f0 of the entire lens system exceeds the lower limit (10.000), spherical aberration and distortion must be properly corrected. can be done. In addition, since the upper limit (18.000) is set for the ratio (d0/f0) between the object-image distance d0 of the entire lens system and the focal length f0 of the entire lens system, it is possible to prevent the lens diameter from becoming too large. At the same time, it is possible to avoid an increase in the total length of the entire lens system. Therefore, the wide-angle lens can be miniaturized.

In the present invention, the object-side lens surface of the third lens is a convex curved surface, so that an imaging area can be secured. In addition, since the fourth lens having positive power is arranged behind the diaphragm, it is possible to correct various aberrations even at a wide angle. In addition, since the fourth lens having positive power is arranged behind the diaphragm, the angle of incidence on the imaging plane can be kept small. Therefore, it is possible to correspond to an imaging element with a large number of pixels. Furthermore, since the fifth group is a cemented lens of the double concave fifth lens and the double convex sixth lens, it is advantageous for correction of lateral chromatic aberration. Therefore, it is possible to suppress the occurrence of chromatic aberration of magnification that accompanies the widening of the angle of view. Also, the absolute value of the ratio (Sag31/(D31/2)) between the sag amount Sag31 of the object-side lens surface of the third lens and the radius (D31/2) of the object-side lens surface of the third lens is the lower limit ( 0), the object-side lens surface of the third lens is not flat. Therefore, various aberrations can be properly corrected. In addition, since the upper limit (0.060) is set for the absolute value of the ratio (Sag31/(D31/2)), a concave surface with a large amount of sag and a convex surface with a large amount of sag are formed between the second lens and the third lens. can be avoided from facing each other. Therefore, multiple reflection between the image-side lens surface of the second lens and the object-side lens surface of the third lens can be suppressed. Therefore, it is possible to suppress the occurrence of a ring-shaped ghost due to multiple reflection between the image-side lens surface of the second lens and the object-side lens surface of the third lens.

1 is an explanatory diagram of a wide-angle lens according to Embodiment 1 of the present invention; FIG. 2 is an explanatory diagram showing spherical aberration of the wide-angle lens shown in FIG. 1; FIG. 2 is an explanatory diagram showing lateral chromatic aberration of the wide-angle lens shown in FIG. 1; FIG. FIG. 2 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens shown in FIG. 1; FIG. 2 is an explanatory diagram showing lateral aberration of the wide-angle lens shown in FIG. 1; FIG. 6 is an explanatory diagram of a wide-angle lens according to Embodiment 2 of the present invention; FIG. 7 is an explanatory diagram showing spherical aberration of the wide-angle lens shown in FIG. 6; FIG. 7 is an explanatory diagram showing lateral chromatic aberration of the wide-angle lens shown in FIG. 6; FIG. 7 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens shown in FIG. 6; FIG. 7 is an explanatory diagram showing lateral aberration of the wide-angle lens shown in FIG. 6; FIG. 10 is an explanatory diagram of a wide-angle lens according to Embodiment 3 of the present invention; FIG. 12 is an explanatory diagram showing spherical aberration of the wide-angle lens shown in FIG. 11; FIG. 12 is an explanatory diagram showing lateral chromatic aberration of the wide-angle lens shown in FIG. 11; FIG. 12 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens shown in FIG. 11; FIG. 12 is an explanatory diagram showing lateral aberration of the wide-angle lens shown in FIG. 11; FIG. 11 is an explanatory diagram of a wide-angle lens according to Embodiment 4 of the present invention; FIG. 17 is an explanatory diagram showing spherical aberration of the wide-angle lens shown in FIG. 16; FIG. 17 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens shown in FIG. 16; FIG. 17 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens shown in FIG. 16; FIG. 17 is an explanatory diagram showing lateral aberration of the wide-angle lens shown in FIG. 16; FIG. 11 is an explanatory diagram of a wide-angle lens according to Embodiment 5 of the present invention; FIG. 22 is an explanatory diagram showing spherical aberration of the wide-angle lens shown in FIG. 21; FIG. 22 is an explanatory diagram showing lateral chromatic aberration of the wide-angle lens shown in FIG. 21; FIG. 22 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens shown in FIG. 21; FIG. 22 is an explanatory diagram showing lateral aberration of the wide-angle lens shown in FIG. 21; FIG. 11 is an explanatory diagram of a wide-angle lens according to Embodiment 6 of the present invention; FIG. 27 is an explanatory diagram showing spherical aberration of the wide-angle lens shown in FIG. 26; FIG. 27 is an explanatory diagram showing lateral chromatic aberration of the wide-angle lens shown in FIG. 26; FIG. 27 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens shown in FIG. 26; FIG. 27 is an explanatory diagram showing lateral aberration of the wide-angle lens shown in FIG. 26;

Embodiments 1, 2, 3, 4, 5, and 6 will be described below as a wide-angle lens 100 to which the present invention is applied. In the present invention, the term "lens surface diameter (Diameter)" means the effective optical diameter of the lens surface. The effective diameter is the diameter of a circle defined by the radially outermost point (the point farthest from the optical axis) when considering the intersection points of all light rays contributing to image formation and the lens surface. “Amount of sag (Sag)” is defined as, when a virtual plane perpendicular to the optical axis is defined as a virtual reference plane, a point on the optical axis L of the virtual reference plane at the outermost circumference of the effective diameter of the lens surface is the distance to a point on the L axis. Further, when the sag amount is a positive value, the point on the optical axis L on the virtual reference plane is positioned closer to the object side than the point on the optical axis L of the lens surface, and when the sag amount is a negative value, the virtual A point on the optical axis L on the reference plane is located closer to the image side than a point on the optical axis L on the lens surface.

(Embodiment 1)
FIG. 1 is an explanatory diagram of a wide-angle lens 100 according to Embodiment 1 of the present invention. It should be noted that "*" is added to the aspherical surfaces in order to represent the surface numbers in FIG. As shown in FIG. 1, the wide-angle lens 100 of this embodiment has a front group 110, a diaphragm 80, a rear group 120, and an infrared cut filter 81 arranged in order from the object side La to the image side Lb. . The front group 110 is composed of a first lens 10, a second lens 20, and a third lens 30 arranged from the most object side La to the image side Lb. The rear group 120 is composed of a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged from the object side La to the image side Lb. On the image side Lb of the sixth lens, a plate-like infrared cut filter 81, a translucent cover 82, and an imaging element 85 are arranged in this order.

The first lens 10 is a negative meniscus lens (meniscus lens having negative power) having a concave curved lens surface 102 (second surface 2) on the image side Lb, and a lens surface 11 (first surface 2) on the object side La. 1) is a convex surface. The second lens is a negative lens (a lens having negative power) in which the lens surface 22 (fourth surface 4) on the image side Lb is a concave surface, and the lens surface 21 (third surface 3) on the object side La is , is a convex surface. The third lens 30 is a biconvex lens in which both the lens surface 31 (fifth surface 5) on the object side La and the lens surface 32 (sixth surface 6) on the image side Lb are convex curved surfaces. power). The fourth lens 40 is a biconvex lens in which both the lens surface 41 (seventh surface 7) on the object side La and the lens surface 42 (eighth surface 8) on the image side Lb are convex curved surfaces. power). The fifth lens is a negative lens (a lens having negative power) in which the lens surface 52 (eleventh surface 11) on the image side Lb is a concave curved surface. 10 surface 10) is a concave curved surface. The sixth lens 60 is a biconvex lens in which a lens surface 61 on the object side La and a lens surface 62 (the twelfth surface 12) on the image side Lb are convex surfaces, and is a positive lens (a lens having positive power). The fifth lens 50 and the sixth lens 60 are cemented lenses in which a lens surface 52 on the image side Lb of the fifth lens 50 and a lens surface 61 on the object side La of the sixth lens 60 are cemented with an adhesive (not shown). The lens surface 52 of the fifth lens 50 on the image side Lb and the lens surface 61 of the sixth lens 60 on the object side La constitute the eleventh surface 11 . According to this configuration, since the fifth lens 50 and the sixth lens 60 constitute the cemented lens 70 on the image side Lb with respect to the diaphragm 80, chromatic aberration can be corrected appropriately. It is desirable that the adhesive be a material that has elasticity even after curing.

A diaphragm 80 constitutes the seventh surface 7 . The surface 811 on the object side La of the infrared cut filter 81 constitutes the 13th surface 13 , and the surface 812 on the image side Lb constitutes the 14th surface 14 . The surface 821 on the object side La of the cover 82 constitutes the fifteenth surface 15 , and the surface 822 on the image side Lb constitutes the sixteenth surface 16 . The imaging surface of the imaging device 85 constitutes the seventeenth surface 17 .

The second lens 20, the third lens 30, the fifth lens 50, and the sixth lens 60 are plastic lenses made of acrylic resin, polycarbonate, polyolefin, or the like. Therefore, cost reduction can be achieved. Also in this case, the first lens 10 and the fourth lens 40 are glass lenses. The fourth lens 40 adjacent to the diaphragm 80 is a glass lens, and the change in refractive index due to temperature change is small. Therefore, the temperature characteristics of the wide-angle lens 100 can be improved. Therefore, a higher resolution can be achieved over a wide temperature range. again. Since the first lens 10 arranged closest to the object side La is a glass lens, the first lens 10 is less likely to be damaged. In this embodiment, the lens surfaces 21 and 22 of the second lens 20, the lens surfaces 31 and 32 of the third lens 30, the lens surfaces 51 and 52 of the fifth lens 50, and the lens surfaces 61 and 62 of the sixth lens 60 are It is aspherical. The lens surfaces 11 and 12 of the first lens 10 and the lens surfaces 41 and 42 of the fourth lens 40 are spherical surfaces.

(lens configuration)
The configuration and the like of each lens of the wide-angle lens 100 of this embodiment are as shown in Table 1. Table 1 shows the following characteristics as the characteristics of the wide-angle lens 100. Note that the values shown in Table 1 and Tables 2 to 7, which will be described later, are rounded off.
Focal length f0 (Effective Focal Length) of the entire lens system
Object-to-image distance d0 of the entire lens system (Total Track)
F value (Image Space) of the entire lens system
Max. Field Angle
Table 1 also shows the following items for each surface. The unit of radius of curvature, thickness and focal length is mm. Here, when the lens surface is a convex surface projecting toward the object side or a concave surface recessed toward the object side, the radius of curvature is assumed to be a positive value, and the lens surface is a convex surface projecting toward the image side or an image surface. If the surface is concave toward the side, the radius of curvature is given as a negative value.
Radius of curvature
Thickness
Refractive index Nd
Abbe number νd
focal length f

Table 1 also shows aspherical surface coefficients A4, A6, A8, A10, . In the following formula, z is the sag amount (axis in the optical axis direction), r is the height in the direction perpendicular to the optical axis (ray height), k is the conic coefficient, and c is the reciprocal of the radius of curvature.

As shown in Table 1, in the wide-angle lens 100 of this embodiment, the focal length f0 of the entire lens system is 0.912 mm. The object-image distance d0 of the entire lens system is 12.463 mm, the F value of the entire lens system is 2.03, and the maximum angle of view is 110 degrees.

(Aberration characteristics of wide-angle lens 100)
FIG. 2 is an explanatory diagram showing spherical aberration of the wide-angle lens 100 shown in FIG. FIG. 3 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens 100 shown in FIG. 1, showing the chromatic aberration of magnification at the maximum angle of view (110.000 deg/half angle). FIG. 4 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens 100 shown in FIG. 5A, 5B, 5C, and 5D are explanatory diagrams showing lateral aberration of the wide-angle lens 100 shown in FIG. , 30°, 60°, 95° are shown in the tangential (Y-direction) and sagittal (X-direction) directions.

2 to 5 show aberrations at wavelengths of 486 nm, 588 nm, and 656 nm with B, G, and R. FIG. As for the astigmatism shown in FIG. 4, S is attached to the characteristic in the sagittal direction, and T is attached to the characteristic in the tangential direction. Further, the distortion shown in FIG. 4 indicates the change ratio of the image between the central portion and the peripheral portion of the imaging, and the smaller the absolute value of the numerical value representing the distortion, the higher the precision of the lens.

As shown in FIGS. 2 to 5, in the wide-angle lens 100 of this embodiment, spherical aberration, chromatic aberration of magnification, astigmatism (distortion), and lateral aberration are corrected to appropriate levels.

(Configuration related to ghost countermeasures, etc.)
Table 2 shows numerical values corresponding to the conditional expressions described below, and FIG. 2 also shows numerical values of Embodiments 2 to 6, which will be described later. Table 2 shows numerical values corresponding to conditional expressions to be described below, and FIG. 2 also shows numerical values of Embodiments 2 to 4, which will be described later. The ratios shown in Table 2 are calculated using the values before rounding off the values shown in Tables 1, 3, 4, 5, 6, and 7, and then rounded off. .

As shown in Tables 1 and 2, when the central thickness of the first lens 10 in the optical axis direction is T1 (mm) and the focal length of the entire lens system is f0 (mm), the following conditional expression (1)
1.500≦T1/f0≦2.000 Conditional expression (1)
meets
In this condition, more preferably 1.600≦T1/f0≦1.850 Conditional expression (1a)
meets More specifically, the center thickness T1 in the optical axis direction of the first lens 10 is 1.691 mm, and the focal length f0 of the entire lens system is 0.912 mm. Therefore, the ratio (T1/f0) is 1.776, which satisfies conditional expression (1).

Since the ratio (T1/f0) exceeds the lower limit (1.500), the thickness of the first lens increases. Therefore, it is possible to prevent the first lens 10 from being damaged by an impact. Moreover, since the upper limit (1.500) is provided for the ratio (T1/f0), it is possible to prevent the first lens 10 from becoming too thick. Therefore, it is possible to prevent the first lens 10 from becoming too thick to obtain a suitable negative power.

When the sag amount of the lens surface 31 on the object side La of the third lens 30 is Sag31 (mm) and the diameter of the lens surface 31 on the object side La of the third lens 30 is D31 (mm), the sag amount Sag31 and the diameter D31 satisfies the following conditional expression (2)
0<|Sag31/(D31/2)|<0.060 Conditional expression (2)
meets More specifically, Sag31 is 0.037 mm and D31 is 2.929 mm. Therefore, the absolute value of the ratio (Sag31/(D31/2)) is 0.025, which satisfies conditional expression (2).

Since the absolute value of the ratio (Sag31/(D31/2)) exceeds the lower limit (0), the lens surface 31 on the object side La of the third lens 30 is not flat. Therefore, various aberrations can be properly corrected. In addition, since the upper limit (0.060) is set for the absolute value of the ratio (Sag31/(D31/2)), a concave surface with a large amount of sag and a convex surface with a large amount of sag are formed between the second lens and the third lens. can be avoided from facing each other. Therefore, multiple reflection can be suppressed between the image-side lens surface of the second lens and the object-side lens surface of the third lens. Therefore, it is possible to suppress the occurrence of a ring-shaped ghost due to multiple reflection between the lens surface 22 of the second lens 20 on the image side Lb and the lens surface 31 of the third lens 30 on the object side La. .

When the focal length of the entire lens system is f0 (mm) and the focal length of the first lens 10 is f1 (mm), the following conditional expression (3)
-6.000<f1/f0<-4.500 Conditional expression (3)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the focal length f1 of the first lens 10 is -4.690 mm. Therefore, the ratio (f1/f0) is -5.144, which satisfies conditional expression (3).

Since the ratio (f1/f0) exceeds the lower limit (−6.000), the wide-angle lens 100 can be widened and downsized. Moreover, since the upper limit (−4.500) is set for the ratio (f1/f0), the refractive power of the first lens 10 becomes proper, and various aberrations can be corrected properly.

When the focal length of the first lens 10 is f1 (mm) and the focal length of the second lens 20 is f2 (mm), the following conditional expression (4)
2.000<f1/f2<2.400 Conditional expression (4)
meets More specifically, the focal length f1 of the first lens 10 is -4.690 mm, and the focal length f2 of the second lens 20 is -2.254 mm. Therefore, the ratio (f1
/f2) is 2.081, which satisfies conditional expression (4).

Since the ratio (f1/f2) exceeds the lower limit (2.000), the wide angle lens 100 can be widened. Moreover, since the upper limit (2.400) is provided for the ratio (f1/f2), distortion can be properly corrected.

When the focal length of the entire lens system is f0 (mm) and the focal length of the third lens is f3 (mm), the following conditional expression (5)
3.500<f3/f0<5.000 Conditional expression (5)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the focal length f3 of the third lens 30 is 3.409 mm. Therefore, the ratio (f3/f0) is 3.738 and satisfies conditional expression (5).

Since the ratio (f3/f0) exceeds the lower limit (3.500), it is possible to avoid the power of the third lens 30 from becoming too strong. Therefore, various aberrations can be properly corrected. Moreover, since the upper limit (5.000) is set for the ratio (f3/f0), the lens diameter and the object-to-object distance d0 of the entire lens system can be reduced. Therefore, the wide-angle lens 100 can be miniaturized.

When the focal length of the entire lens system is f0 (mm) and the focal length of the second lens 20 is f2 (mm), the following conditional expression (6)
-2.800<f2/f0<-2.100 Conditional expression (6)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the focal length f2 of the second lens 20 is -2.254 mm. Therefore, the ratio (f2/f0) is -2.472, which satisfies conditional expression (6).

Since the ratio (f2/f0) exceeds the lower limit (-2.800), the lens diameter and the object-to-object distance d0 of the entire lens system can be reduced. Therefore, the wide-angle lens 100 can be miniaturized. Moreover, since the upper limit (-2.100) is set for the ratio (f2/f0), it is possible to avoid the power of the second lens 20 from becoming too strong. Therefore, an imaging area can be secured and various aberrations can be corrected appropriately.

When the focal length of the entire lens system is f0 (mm) and the focal length of the fourth lens 40 is f4 (mm), the following conditional expression (7)
2.800<f4/f0<4.000 Conditional expression (7)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the focal length f4 of the fourth lens 40 is 2.947 mm. Therefore, the ratio (f4/f0) is 3.232 and satisfies conditional expression (7).

Since the ratio (f4/f0) exceeds the lower limit (2.800), it is possible to avoid the power of the fourth lens 40 from becoming too strong. Therefore, various aberrations can be properly corrected. Also, since the upper limit (4.000) is set for the ratio (f4/f0), the lens diameter and the object-to-object distance d0 of the entire lens system can be reduced. Therefore, the wide-angle lens 100 can be miniaturized.

When the focal length of the entire lens system is f0 (mm) and the composite focal length of the fourth lens 40, the fifth lens 50 and the sixth lens 60 is f456 (mm), the following conditional expression (8)
2.000<f456/f0<3.000 Conditional expression (8)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the combined focal length f456 of the fourth lens 40, fifth lens 50 and sixth lens 60 is 2.0 mm.
708 mm. Therefore, the ratio (f456/f0) is 2.970 and satisfies conditional expression (8).

Since the ratio (f456/f0) exceeds the lower limit (2.000), it is possible to avoid the power of the rear group 120 from becoming too strong. Therefore, various aberrations can be properly corrected. Therefore, high optical characteristics can be realized. Moreover, since the upper limit (3.000) is set for the ratio (f456/f0), it is possible to prevent the power of the rear group 120 from becoming too weak. Therefore, the wide-angle lens 100 can be miniaturized.

When the focal length of the entire lens system is f0 (mm) and the combined focal length of the fifth lens 50 and the sixth lens 60 is f56 (mm), the following conditional expression (9)
5.000<f56/f0<7.000 Conditional expression (9)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the combined focal length f56 of the fifth lens 50 and the sixth lens 60 is 5.518 mm. Therefore, the ratio (f56/f0) is 6.052 and satisfies conditional expression (9).

Chromatic aberration can be properly corrected when the ratio (f56/f0) is within the range of the conditions.

When the focal length of the entire lens system is f0 (mm) and the curvature radius on the optical axis of the lens surface 42 on the image side Lb of the fourth lens 40 is R42, the following conditional expression (10)
-5.000<R42/f0<-2.800 Conditional expression (10)
meets More specifically, the focal length f0 of the entire lens system is 0.912 mm, and the curvature radius R42 on the optical axis of the lens surface 42 on the image side Lb of the fourth lens 40 is -2.849 mm. Therefore, the ratio (R42/f0) is -3.125, which satisfies conditional expression (10).

Since the ratio (R42/f0) exceeds the lower limit (-5.000), various aberrations can be properly corrected. Further, since the upper limit (−2.800) is provided for the ratio (R42/f0), it is possible to suppress the radius of curvature of the lens surface 42 on the image side Lb of the fourth lens 40 from becoming too small on the optical axis. . Therefore, the lens surface 42 on the image side Lb of the fourth lens 40 can be shaped.

When the object-to-image distance of the entire lens system is d0 and the focal length of the entire lens system is f0, the following conditional expression (11)
10.000<d0/f0<18.000 Conditional expression (11)
meets More specifically, the object-image distance d0 of the entire lens system is 12.463 mm, and the focal length f0 of the entire lens system is 0.912 mm. Therefore, the ratio (d0/f0) is 13.669, which satisfies conditional expression (11).

Since the ratio (d0/f0) exceeds the lower limit (10.000), spherical aberration and distortion can be properly corrected. Since the upper limit (18.000) is provided for the ratio (d0/f0), it is possible to prevent the lens diameter from becoming too large and to avoid the total length of the entire lens system from becoming long. Therefore, the wide-angle lens 100 can be miniaturized.

(Embodiment 2)
FIG. 6 is an explanatory diagram of the wide-angle lens 100 according to Embodiment 2 of the present invention. FIG. 7 is an explanatory diagram showing spherical aberration of the wide-angle lens 100 shown in FIG. FIG. 8 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens 100 shown in FIG. 6, showing the chromatic aberration of magnification at the maximum angle of view (110.000 deg/half angle). FIG. 9 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens 100 shown in FIG. 10A, 10B, 10C, and 10D are explanatory diagrams showing lateral aberration of the wide-angle lens 100 shown in FIG. , 30°, 60°, 95° are shown in the tangential (Y-direction) and sagittal (X-direction) directions.

As shown in FIG. 6, the wide-angle lens 100 of this embodiment also includes a front group 110, a diaphragm 80, a rear group 120, and an infrared cut filter arranged in order from the object side La to the image side Lb, as in the first embodiment. 81. The front group 110 is composed of a first lens 10, a second lens 20, and a third lens 30 arranged from the most object side La to the image side Lb. The rear group 120 is composed of a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged from the object side La to the image side Lb.

The configuration and the like of each lens of the wide-angle lens 100 of this embodiment are as shown in Table 3. In the wide-angle lens 100 of this embodiment, the focal length f0 of the entire lens system is 0.922 mm, and the total length, which is the distance from the lens surface 11 of the first lens 10 to the image sensor 85, is 12.501 mm. The overall F value is 2.0, and the maximum angle of view is 110 degrees. As shown in FIGS. 7 to 10, in the wide-angle lens 100 of this embodiment, spherical aberration, chromatic aberration of magnification, astigmatism (distortion), and lateral aberration are corrected to appropriate levels.

As shown in Table 2, the wide-angle lens 100 of the present embodiment satisfies conditional expressions (1), (2), (3), (4), (5), (6), and (7) described in the first embodiment. , (8), (9), (10), and (11) are satisfied, the same effect as in the first embodiment can be obtained.

More specifically, the center thickness T1 in the optical axis direction of the first lens 10 is 1.600 mm, and the focal length f0 of the entire lens system is 0.922 mm. Therefore, the ratio (T1/f0) is 1.736, which satisfies conditional expression (1) and condition (1a).

More specifically, Sag31 is 0.052 mm and D31 is 2.980. Therefore, the absolute value of the ratio (Sag31/(D31/2)) is 0.035, which satisfies conditional expression (2).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f1 of the first lens 10 is -4.981 mm. Therefore, the ratio (f1/f0) is -5.
404, which satisfies conditional expression (3).

More specifically, the focal length f1 of the first lens 10 is -4.981 mm, and the focal length f2 of the second lens 20 is -2.301 mm. Therefore, the ratio (f1/f2) is 2.165 and satisfies conditional expression (4).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f3 of the third lens 30 is 3.790 mm. Therefore, the ratio (f3/f0) is 4.111 and satisfies conditional expression (5).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f2 of the second lens 20 is -2.301 mm. Therefore, the ratio (f2/f0) is -2.496, which satisfies conditional expression (6).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f4 of the fourth lens 40 is 2.848 mm. Therefore, the ratio (f4/f0) is 3.090, which satisfies conditional expression (7).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the combined focal length f456 of the fourth lens 40, fifth lens 50 and sixth lens 60 is 2.665 mm. Therefore, the ratio (f456/f0) is 2.891 and satisfies conditional expression (8).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the combined focal length f56 of the fifth lens 50 and the sixth lens 60 is 5.468 mm. Therefore, the ratio (f56/f0) is 5.931 and satisfies conditional expression (9).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the radius of curvature R42 on the optical axis of the lens surface 42 on the image side Lb of the fourth lens 40 is -2.876 mm. Therefore, the ratio (R42/f0) is -3.120, which satisfies conditional expression (10).

More specifically, the object-image distance d0 of the entire lens system is 12.501 mm, and the focal length f0 of the entire lens system is 0.922 mm. Therefore, the ratio (d0/f0) is 13.561, which satisfies conditional expression (11).

(Embodiment 3)
FIG. 11 is an explanatory diagram of the wide-angle lens 100 according to Embodiment 3 of the present invention. FIG. 12 is an explanatory diagram showing spherical aberration of the wide-angle lens 100 shown in FIG. FIG. 13 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens 100 shown in FIG. 11, showing the chromatic aberration of magnification at the maximum angle of view (100.000 deg/half angle). FIG. 14 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens 100 shown in FIG. 15A, 15B, 15C, and 15D are explanatory diagrams showing lateral aberration of the wide-angle lens 100 shown in FIG. , 30°, 60°, 95° are shown in the tangential (Y-direction) and sagittal (X-direction) directions.

As shown in FIG. 11, the wide-angle lens 100 of this embodiment also includes a front group 110, a diaphragm 80, a rear group 120, and an infrared cut filter arranged in order from the object side La to the image side Lb, as in the first embodiment. 81. The front group 110 is composed of a first lens 10, a second lens 20, and a third lens 30 arranged from the most object side La to the image side Lb. rear group 120
consists of a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged from the object side La to the image side Lb.

The configuration and the like of each lens of the wide-angle lens 100 of this embodiment are as shown in Table 4. In the wide-angle lens 100 of this embodiment, the focal length f0 of the entire lens system is 0.922 mm, and the total length, which is the distance from the lens surface 11 of the first lens 10 to the image sensor 85, is 12.501 mm. The overall F value is 2.0, and the maximum angle of view is 100 degrees. As shown in FIGS. 12 to 15, in the wide-angle lens 100 of this embodiment, spherical aberration, chromatic aberration of magnification, astigmatism (distortion), and lateral aberration are corrected to appropriate levels.

As shown in Table 2, the wide-angle lens 100 of the present embodiment satisfies conditional expressions (1), (2), (3), (4), (5), (6), and (7) described in the first embodiment. , (8), (9), (10), and (11) are satisfied, the same effect as in the first embodiment can be obtained.

More specifically, the center thickness T1 in the optical axis direction of the first lens 10 is 1.600 mm, and the focal length f0 of the entire lens system is 0.922 mm. Therefore, the ratio (T1/f0) is 1.736, which satisfies conditional expressions (1) and (1a).

More specifically, Sag31 is 0.053 mm and D31 is 2.979 mm. Therefore, the absolute value of the ratio (Sag31/(D31/2)) is 0.035, which satisfies conditional expression (2).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f1 of the first lens 10 is -4.982 mm. Therefore, the ratio (f1/f0) is -5.404, which satisfies conditional expression (3).

More specifically, the focal length f1 of the first lens 10 is -4.982 mm, and the focal length f2 of the second lens 20 is -2.299 mm. Therefore, the ratio (f1/f2) is 2.166 and satisfies conditional expression (4).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f3 of the third lens 30 is 3.789 mm. Therefore, the ratio (f3/f0) is 4.110 and satisfies conditional expression (5).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f2 of the second lens 20 is -2.299 mm. Therefore, the ratio (f2/f0) is -2.494, which satisfies conditional expression (6).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the focal length f4 of the fourth lens 40 is 2.848 mm. Therefore, the ratio (f4/f0) is 3.090, which satisfies conditional expression (7).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the combined focal length f456 of the fourth lens 40, fifth lens 50 and sixth lens 60 is 2.665 mm. Therefore, the ratio (f456/f0) is 2.891 and satisfies conditional expression (8).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the combined focal length f56 of the fifth lens 50 and the sixth lens 60 is 5.460 mm. Therefore, the ratio (f56/f0) is 5.923 and satisfies conditional expression (9).

More specifically, the focal length f0 of the entire lens system is 0.922 mm, and the radius of curvature R42 on the optical axis of the lens surface 42 on the image side Lb of the fourth lens 40 is -2.876 mm. Therefore, the ratio (R42/f0) is -3.120, which satisfies conditional expression (10).

More specifically, the object-image distance d0 of the entire lens system is 12.501 mm, and the focal length f0 of the entire lens system is 0.922 mm. Therefore, the ratio (d0/f0) is 13.560, which satisfies conditional expression (11).

(Embodiment 4)
FIG. 16 is an explanatory diagram of the wide-angle lens 100 according to Embodiment 4 of the present invention. FIG. 17 is an explanatory diagram showing spherical aberration of the wide-angle lens 100 shown in FIG. FIG. 18 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens 100 shown in FIG. 16, showing the chromatic aberration of magnification at the maximum angle of view (110.000 deg/half angle). FIG. 19 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens 100 shown in FIG. 20A, 20B, 20C, and 20D are explanatory diagrams showing lateral aberration of the wide-angle lens 100 shown in FIG. , 30°, 60°, 95° are shown in the tangential (Y-direction) and sagittal (X-direction) directions.

As shown in FIG. 16, the wide-angle lens 100 of this embodiment also includes a front group 110, a diaphragm 80, a rear group 120, and an infrared cut filter arranged in order from the object side La to the image side Lb, as in the first embodiment. 81. The front group 110 is composed of a first lens 10, a second lens 20, and a third lens 30 arranged from the most object side La to the image side Lb. The rear group 120 is composed of a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged from the object side La to the image side Lb.

The configuration and the like of each lens of the wide-angle lens 100 of this embodiment are as shown in Table 5. In the wide-angle lens 100 of this embodiment, the focal length f0 of the entire lens system is 0.933 mm, and the total length, which is the distance from the lens surface 11 of the first lens 10 to the image sensor 85, is 12.500 mm. The overall F value is 2.0, and the maximum angle of view is 110 degrees. As shown in FIGS. 17 to 20, in the wide-angle lens 100 of this embodiment, spherical aberration, chromatic aberration of magnification, astigmatism (distortion), and lateral aberration are corrected to appropriate levels.

As shown in Table 2, the wide-angle lens 100 of the present embodiment satisfies conditional expressions (1), (2), (3), (4), (5), (6), and (7) described in the first embodiment. , (8), (9), (10), and (11) are satisfied, the same effect as in the first embodiment can be obtained.

More specifically, the center thickness T1 in the optical axis direction of the first lens 10 is 1.567 mm, and the focal length f0 of the entire lens system is 0.933 mm. Therefore, the ratio (T1/f0) is 1.680, which satisfies conditional expressions (1) and (1a).

More specifically, Sag31 is 0.054 mm and D31 is 2.984 mm. Therefore, the absolute value of the ratio (Sag31/(D31/2)) is 0.036, which satisfies conditional expression (2).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the focal length f1 of the first lens 10 is -4.892 mm. Therefore, the ratio (f1/f0) is -5.
242, which satisfies conditional expression (3).

More specifically, the focal length f1 of the first lens 10 is -4.892 mm, and the focal length f2 of the second lens 20 is -2.355 mm. Therefore, the ratio (f1/f2) is 2.077, which satisfies conditional expression (4).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the focal length f3 of the third lens 30 is 3.779 mm. Therefore, the ratio (f3/f0) is 4.050, which satisfies conditional expression (5).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the focal length f2 of the second lens 20 is -2.355 mm. Therefore, the ratio (f2/f0) is -2.524, which satisfies conditional expression (6).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the focal length f4 of the fourth lens 40 is 2.863 mm. Therefore, the ratio (f4/f0) is 3.068 and satisfies conditional expression (7).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the combined focal length f456 of the fourth lens 40, fifth lens 50 and sixth lens 60 is 2.710 mm. Therefore, the ratio (f456/f0) is 2.904, which satisfies conditional expression (8).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the combined focal length f56 of the fifth lens 50 and the sixth lens 60 is 5.833 mm. Therefore, the ratio (f56/f0) is 6.251 and satisfies conditional expression (9).

More specifically, the focal length f0 of the entire lens system is 0.933 mm, and the curvature radius R42 on the optical axis of the lens surface 42 on the image side Lb of the fourth lens 40 is -2.898 mm. Therefore, the ratio (R42/f0) is -3.105, which satisfies conditional expression (10).

More specifically, the object-to-image distance d0 of the entire lens system is 12.500 mm, and the focal length f0 of the entire lens system is 0.933 mm. Therefore, the ratio (d0/f0) is 13.395, which satisfies conditional expression (11).

(Embodiment 5)
FIG. 21 is an explanatory diagram of the wide-angle lens 100 according to Embodiment 5 of the present invention. FIG. 22 is an explanatory diagram showing spherical aberration of the wide-angle lens 100 shown in FIG. FIG. 23 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens 100 shown in FIG. 21, showing the chromatic aberration of magnification at the maximum angle of view (110.000 deg/half angle). FIG. 24 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens 100 shown in FIG. 25A, 25B, 25C, and 25D are explanatory diagrams showing lateral aberration of the wide-angle lens 100 shown in FIG. , 30°, 60°, 95° are shown in the tangential (Y-direction) and sagittal (X-direction) directions.

As shown in FIG. 21, the wide-angle lens 100 of this embodiment also includes a front group 110, a diaphragm 80, a rear group 120, and an infrared cut filter arranged in order from the object side La to the image side Lb, as in the first embodiment. 81. The front group 110 is composed of a first lens 10, a second lens 20, and a third lens 30 arranged from the most object side La to the image side Lb. rear group 120
consists of a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged from the object side La to the image side Lb.

The configuration and the like of each lens of the wide-angle lens 100 of this embodiment are as shown in Table 6. In the wide-angle lens 100 of this embodiment, the focal length f0 of the entire lens system is 0.916 mm, and the total length, which is the distance from the lens surface 11 of the first lens 10 to the image sensor 85, is 12.500 mm. The overall F value is 1.99, and the maximum angle of view is 110 degrees. As shown in FIGS. 22 to 25, in the wide-angle lens 100 of this embodiment, spherical aberration, chromatic aberration of magnification, astigmatism (distortion), and lateral aberration are corrected to appropriate levels.

As shown in Table 2, the wide-angle lens 100 of the present embodiment satisfies conditional expressions (1), (2), (3), (4), (5), (6), and (7) described in the first embodiment. , (8), (9), and (11) are satisfied, the same effect as in the first embodiment can be obtained.

More specifically, the center thickness T1 in the optical axis direction of the first lens 10 is 1.825 mm, and the focal length f0 of the entire lens system is 0.916 mm. Therefore, the ratio (T1/f0) is 1.992, which satisfies conditional expression (1).

More specifically, Sag31 is -0.003 mm and D31 is 2.447 mm. Therefore, the absolute value of the ratio (Sag31/(D31/2)) is 0.002, which satisfies conditional expression (2).

More specifically, the focal length f0 of the entire lens system is 0.916 mm, and the focal length f1 of the first lens 10 is -4.665 mm. Therefore, the ratio (f1/f0) is -5.092, which satisfies conditional expression (3).

More specifically, the focal length f1 of the first lens 10 is -4.665 mm, and the focal length f2 of the second lens 20 is -2.060 mm. Therefore, the ratio (f1/f2) is 2.265 and satisfies conditional expression (4).

More specifically, the focal length f0 of the entire lens system is 0.916 mm, and the focal length f3 of the third lens 30 is 3.268 mm. Therefore, the ratio (f3/f0) is 3.566 and satisfies conditional expression (5).

More specifically, the focal length f0 of the entire lens system is 0.916 mm, and the focal length f2 of the second lens 20 is -2.060 mm. Therefore, the ratio (f2/f0) is -2.248, which satisfies conditional expression (6).

More specifically, the focal length f0 of the entire lens system is 0.916 mm, and the focal length f4 of the fourth lens 40 is 2.719 mm. Therefore, the ratio (f4/f0) is 2.968 and satisfies conditional expression (7).

More specifically, the focal length f0 of the entire lens system is 0.916 mm, and the combined focal length f456 of the fourth lens 40, fifth lens 50 and sixth lens 60 is 2.738 mm. Therefore, the ratio (f456/f0) is 2.988 and satisfies conditional expression (8).

More specifically, the focal length f0 of the entire lens system is 0.916 mm, and the combined focal length f56 of the fifth lens 50 and the sixth lens 60 is 5.281 mm. Therefore, the ratio (f56/f0) is 5.764 and satisfies conditional expression (9).

More specifically, the object-image distance d0 of the entire lens system is 12.500 mm, and the focal length f0 of the entire lens system is 0.916 mm. Therefore, the ratio (d0/f0) is 13.643, which satisfies conditional expression (11).

(Embodiment 6)
FIG. 26 is an explanatory diagram of the wide-angle lens 100 according to Embodiment 5 of the present invention. FIG. 27 is an explanatory diagram showing spherical aberration of the wide-angle lens 100 shown in FIG. FIG. 28 is an explanatory diagram showing the chromatic aberration of magnification of the wide-angle lens 100 shown in FIG. 26, showing the chromatic aberration of magnification at the maximum angle of view (110.000 deg/half angle). FIG. 29 is an explanatory diagram showing astigmatism and distortion of the wide-angle lens 100 shown in FIG. 30A, 30B, 30C, and 30D are explanatory diagrams showing lateral aberration of the wide-angle lens 100 shown in FIG. , 30°, 60°, 95° are shown in the tangential (Y-direction) and sagittal (X-direction) directions.

As shown in FIG. 26, the wide-angle lens 100 of this embodiment also includes a front group 110, a diaphragm 80, a rear group 120, and an infrared cut filter arranged in order from the object side La to the image side Lb, as in the first embodiment. 81. The front group 110 is composed of a first lens 10, a second lens 20, and a third lens 30 arranged from the most object side La to the image side Lb. The rear group 120 consists of a fourth lens 40, a fifth lens 50, and a sixth lens 60 arranged from the object side La to the image side Lb. In this embodiment, the lens surface 21 (the third surface 3) on the object side La of the second lens 20 is a concave curved surface. Other basic configurations are the same as those of the first embodiment.

The configuration and the like of each lens of the wide-angle lens 100 of this embodiment are as shown in Table 7. In the wide-angle lens 100 of this embodiment, the focal length f0 of the entire lens system is 0.935 mm, and the total length, which is the distance from the lens surface 11 of the first lens 10 to the image sensor 85, is 12.499 mm. The overall F value is 1.99, and the maximum angle of view is 110 degrees. As shown in FIGS. 27 to 30, in the wide-angle lens 100 of this embodiment, spherical aberration, chromatic aberration of magnification, astigmatism (distortion), and lateral aberration are corrected to appropriate levels.

As shown in Table 2, the wide-angle lens 100 of the present embodiment satisfies conditional expressions (1), (2), (3), (5), (6), (7), and (8) described in the first embodiment. , (9), (10), and (11) are satisfied, the same effect as in the first embodiment can be obtained.

More specifically, the center thickness T1 in the optical axis direction of the first lens 10 is 1.508 mm, and the focal length f0 of the entire lens system is 0.935 mm. Therefore, the ratio (T1/f0) is 1.614, which satisfies conditional expressions (1) and (1a).

More specifically, Sag31 is 0.053 mm and D31 is 3.028 mm. Therefore, the absolute value of the ratio (Sag31/(D31/2)) is 0.035, which satisfies conditional expression (2).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the focal length f1 of the first lens 10 is -4.741 mm. Therefore, the ratio (f1/f0) is -5.074, which satisfies conditional expression (3).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the focal length f3 of the third lens 30 is 4.116 mm. Therefore, the ratio (f3/f0) is 4.405, which satisfies conditional expression (5).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the focal length f2 of the second lens 20 is -2.421 mm. Therefore, the ratio (f2/f0) is -2.591, which satisfies conditional expression (6).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the focal length f4 of the fourth lens 40 is 3.336 mm. Therefore, the ratio (f4/f0) is 3.570 and satisfies conditional expression (7).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the combined focal length f456 of the fourth lens 40, fifth lens 50 and sixth lens 60 is 2.757 mm. Therefore, the ratio (f456/f0) is 2.951 and satisfies conditional expression (8).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the combined focal length f56 of the fifth lens 50 and the sixth lens 60 is 5.859 mm. Therefore, the ratio (f56/f0) is 6.270 and satisfies conditional expression (9).

More specifically, the focal length f0 of the entire lens system is 0.935 mm, and the curvature radius R42 on the optical axis of the lens surface 42 on the image side Lb of the fourth lens 40 is -3.165 mm. Therefore, the ratio (R42/f0) is -3.387, which satisfies conditional expression (10).

More specifically, the object-image distance d0 of the entire lens system is 12.499 mm, and the focal length f0 of the entire lens system is 0.935 mm. Therefore, the ratio (d0/f0) is 13.375, which satisfies conditional expression (11).

(Other embodiments)
Although the first lens 10 is a glass lens in the above embodiment, it may be a plastic lens. In this case, the lens surface 102 on the image side Lb of the first lens 10 can be made aspherical.

DESCRIPTION OF SYMBOLS 10... 1st lens, 20... 2nd lens, 30... 3rd lens, 40... 4th lens, 50... 5th lens, 60... 6th lens, 70... cemented lens, 80... diaphragm, 81... infrared cut filter , 85... Imaging device 100... Wide-angle lens 110... Front group 120... Rear group

Claims (10)

The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression 0<|Sag31/(D31/2)|<0.060
satisfy the
Assuming that the center thickness of the first lens in the optical axis direction is T1 (mm) and the focal length of the entire lens system is f0 (mm), the following conditional expression
1.500≤T1/f0≤1.850
A wide-angle lens characterized by satisfying The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged from the most object side to the image side.
are arranged in order,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the entire lens system is f0 (mm) and the focal length of the first lens is f1 (mm), the following conditional expression
-6.000<f1/f0<-4.500
A wide-angle lens characterized by satisfying The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the first lens is f1 (mm) and the focal length of the second lens is f2 (mm), the following conditional expression
2.000<f1/f2<2.400
A wide-angle lens characterized by satisfying When the focal length of the entire lens system is f0 (mm) and the focal length of the third lens is f3 (mm), the following conditional expression: 3.500<f3/f0<5.000
4. The wide-angle lens according to any one of claims 1 to 3 , wherein: The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the entire lens system is f0 (mm) and the focal length of the second lens is f2 (mm), the following conditional expression
-2.800<f2/f0<-2.100
A wide-angle lens characterized by satisfying The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the entire lens system is f0 (mm) and the focal length of the fourth lens is f4 (mm), the following conditional expression
2.800<f4/f0<4.000
A wide-angle lens characterized by satisfying The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the entire lens system is f0 (mm) and the combined focal length of the fourth lens, the fifth lens and the sixth lens is f456 (mm), the following conditional expression
2.000<f456/f0<3.000
A wide-angle lens characterized by satisfying The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the entire lens system is f0 (mm) and the combined focal length of the fifth lens and the sixth lens is f56 (mm), the following conditional expression
5.000<f56/f0<7.000
A wide-angle lens characterized by satisfying The front group, the diaphragm, and the rear group are arranged in order from the object side to the image side,
In the front group, a first lens, a second lens and a third lens are arranged in order from the most object side to the image side,
In the rear group, a fourth lens, a fifth lens and a sixth lens are arranged in order from the most object side to the image side,
the first lens is a negative meniscus lens having a concave curved surface on the image side;
the second lens is a negative lens having a concave curved surface on the image side;
the third lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fourth lens is a biconvex lens in which both the object-side lens surface and the image-side lens surface are convex surfaces;
the fifth lens is a negative lens having a concave curved surface on the image side;
the sixth lens is a biconvex lens in which the object-side lens surface and the image-side lens surface are convex surfaces;
The fifth lens and the sixth lens are cemented lenses in which an image-side lens surface of the fifth lens and an object-side lens surface of the sixth lens are cemented together,
Sag31 (mm) is the sag amount of the object-side lens surface of the third lens, and D31 (mm) is the diameter of the object-side lens surface of the third lens. conditional expression of
0<|Sag31/(D31/2)|<0.060
The filling,
When the focal length of the entire lens system is f0 (mm) and the radius of curvature of the image-side lens surface of the fourth lens on the optical axis is R42, the following conditional expression
-5.000<R42/f0<-2.800
A wide-angle lens characterized by satisfying When the object-image distance of the entire lens system is d0 and the focal length of the entire lens system is f0, the following conditional expression: 10.000<d0/f0<18.000
10. The wide-angle lens according to any one of claims 1 to 9 , characterized by satisfying:

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