Patent Application
20190049700
The present disclosure relates to an imaging lens that forms an optical image of an object on an imaging device such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal Oxide Semiconductor), and to an imaging apparatus that is mounted with the imaging lens to perform photographing, such as a digital still camera, a mobile phone with a camera, and an information mobile terminal with a camera.
A thin digital still camera such as a card type camera is fabricated year after year, and reduction in size of an imaging apparatus is demanded. In addition, reduction in size of the imaging apparatus is also demanded in a mobile phone in order to reduce the thickness of the terminal itself and to secure a space for a lot of functions to be mounted. Therefore, demand for further reduction in size of the imaging lens mounted on the imaging apparatus is increasing.
In addition, together with reduction in size of the imaging device such as a CCD and a CMOS, the number of pixels is greatly increased by microfabrication of the pixel pitch of the imaging device. In accordance therewith, high performance is also demanded for the imaging lens used in the imaging apparatus.
PTL 1: Japanese Unexamined Patent Application Publication No. 2015-072404
PTL 2: Japanese Unexamined Patent Application Publication No. 2014-145961
In recent years, to address an imaging device with the increased number of pixels, development has been demanded, as the imaging lens, of a lens system that has high image-forming performance in the range from a center angle of view to a peripheral angle of view while achieving reduction of the total length. Furthermore, reduction of image deterioration due to ghost or flare has been demanded.
It is desirable to provide an imaging lens that makes it possible to favorably correct various aberrations while the lens is small-sized, and reduce image deterioration caused due to unnecessary light, and an imaging apparatus that is mounted with such an imaging lens.
A first imaging lens according to an embodiment of the present disclosure includes, in order from object side toward image plane side, a first lens having a meniscus shape, the meniscus shape having a shape that is positioned near an optical axis and includes a convex surface that faces the object side, a second lens including a convex surface that faces, near the optical axis, the object side, and having, near the optical axis, positive refractive power, a third lens having, near the optical axis, negative refractive power, a fourth lens, a fifth lens, a sixth lens having, near the optical axis, positive refractive power, and a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point.
A first imaging apparatus according to an embodiment of the present disclosure is provided with an imaging lens and an imaging device that outputs an imaging signal based on an optical image formed by the imaging lens. The imaging lens includes the first imaging lens according to the embodiment of the above-described present disclosure.
A second imaging lens according to an embodiment of the present disclosure includes, in order from object side toward image plane side, a first lens, a second lens that has, near the optical axis, positive refractive power, a third lens that has, near the optical axis, negative refractive power, a fourth lens, a fifth lens, a sixth lens that has, near the optical axis, positive refractive power, and a seventh lens that has, near the optical axis, negative refractive power, and includes a lens surface, on the image plane side, that has an aspherical shape having an inflection point, in which a following conditional expression is satisfied,
−0.5<f/f1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.
A second imaging apparatus according to an embodiment of the present disclosure is provided with an imaging lens and an imaging device that outputs an imaging signal based on an optical image formed by the imaging lens. The imaging lens includes the second imaging lens according to the embodiment of the present disclosure.
The first and second imaging lenses or the first and second imaging apparatuses according to the respective embodiments of the present disclosure each have a configuration including seven lenses as a whole, and the optimization of the configuration of each lens is achieved.
The first and second imaging lenses or the first and second imaging apparatuses according to the respective embodiments of the present disclosure each have a configuration including seven lenses as a whole, and the optimization of the configuration of each lens is achieved. This makes it possible to favorably correct various aberrations while the lens is small-sized, and to reduce image deterioration caused due to unnecessary light.
It is to be noted that effects described here are non-limiting. Any of effects described in the present disclosure may be provided.
Some embodiments of the present disclosure are described in detail below with reference to drawings. It is to be noted that the description is given in the following order.
3. Application Example to Imaging apparatus
High resolution is demanded for an imaging lens used in an imaging device with high definition; however, the resolution is limited by an F value. It has become difficult to obtain sufficient performance by the F value of about 2.0 because a bright lens with a small F value provides high resolution. Accordingly, an imaging lens with the F value of about 1.6 that is suitable to the small-sized imaging device with a large number of pixels and high definition has been increasingly demanded. As the imaging lens for such a purpose, an imaging lens including seven lenses that allows for increase in aperture ratio and improvement in performance as compared with an imaging lens including five or six lenses has been proposed in PTL 1 (Japanese Unexamined Patent Application Publication No. 2015-072404) and PTL 2 (Japanese Unexamined Patent Application Publication No. 2014-145961).
For example, in the imaging lens including seven lenses described in PTL 1, a bright lens is proposed which includes, in order from object side toward image plane side, a first lens, a positive second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. Further, in the imaging lens including seven lenses described in PTL 2, a lens with a brightness of the F value of about 1.6 is proposed which includes, in order from object side toward image plane side, a positive first lens having a convex surface facing the object side near an optical axis, a positive second lens having convex surfaces facing the object side and the image plane side near the optical axis, a negative third lens having a concave surface facing the image plane side near the optical axis, a fourth lens having at least one aspherical surface, a fifth lens having a meniscus shape in which the concave surface of the fifth lens faces the object side near the optical axis, and a sixth lens having both aspherical surfaces, and a seventh lens having a concave surface facing the image plane side near the optical axis and having negative refractive power, in which both faces are in an aspherical shape.
In recent years, to address the imaging device with the increased number of pixels, development of a lens system that has high image-forming performance in the range from a center angle of view to a peripheral angle of view while achieving reduction of the total length has been demanded as the imaging lens. A bright imaging lens with a large aperture is proposed in the above-described PTL 1; however, the shape of the lens surface of the first lens on the object side is concave on the object side, or the first lens has both convex shapes, which is an unfavorable shape for the purpose of reducing the total length. The ratio of a maximum image height to the total length is no less than 1.7. Further, a bright imaging lens, with the F value of 1.6, including seven lenses is proposed in the above-described PTL 2; however, the ratio of the maximum image height to the total length is no less than 1.8. There is room for improvement in the imaging lenses described in the above-described PTL 1 and PTL 2 for the purpose of reducing the optical length while maintaining the performance with a large aperture. Further, when the imaging lens is reduced in profile, the distance between an optical surface and an imaging surface becomes short. This causes reflected light to easily enter the imaging surface from the optical surface, and the tendency to generate ghost or flare becomes remarkable. In particular, in a case where an F number of the imaging lens is made small in accordance with a demand for increase in aperture of a lens in relation to improvement in performance, an effective diameter of the lens becomes large, and a diameter of a light shielding member accordingly becomes large, and moreover, the possibility of the above-described ghost or flare being increased becomes higher.
Accordingly, it is desirable to provide an imaging lens and an imaging apparatus that make it possible to efficiently suppress ghost or flare and to favorably correct various aberrations while being small-sized and having a large aperture.
In
In the following, a configuration of the imaging lens according to the present embodiment is described, as appropriate, in association with configuration examples illustrated in
The imaging lens according to the present embodiment substantially includes seven lenses in which a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 are disposed along the optical axis Z1 in order from the object side toward the image plane side.
The first lens L1 desirably has a meniscus shape. The meniscus shape has a shape that is positioned near an optical axis and includes a convex surface that faces the object side. The first lens L1 desirably has, near the optical axis, positive or negative refractive power.
The second lens L2 desirably includes a convex surface that faces, near the optical axis, the object side. The second lens L2 desirably has, near the optical axis, positive refractive power.
The third lens L3 desirably has, near the optical axis, negative refractive power.
The fourth lens L4 desirably has, near the optical axis, positive or negative refractive power.
The fifth lens L5 desirably has, near the optical axis, positive or negative refractive power.
The sixth lens L6 desirably has, near the optical axis, positive refractive power.
The seventh lens L7 desirably has, near the optical axis, negative power. The seventh lens L7 includes a lens surface. The lens surface is positioned on image plane side and desirably has an aspherical shape that has an inflection point that changes a concave-convex shape in the middle thereof, as it goes from a center part to a peripheral part, and desirably has at least one inflection point at a part other than the intersection with the optical axis Z1. More specifically, the lens surface, on the image side, of the seventh lens L7 desirably has an aspherical shape including a concave shape near the optical axis and a convex shape at a peripheral part.
In addition, an imaging lens according to the present embodiment desirably satisfies a later-described predetermined conditional expression, etc.
Next, workings and effects of an imaging lens according to the present embodiment are described. A more desirable configuration in an imaging lens according to the present embodiment is described together.
It is to be noted that the effects described in the present specification are illustrative and non-limiting. Effects other than those described in the present specification may be provided.
An imaging lens according to the present embodiment has a configuration including seven lenses as a whole, and the optimization of the configuration of each lens is achieved. This makes it possible to favorably correct various aberrations while the lens is small-sized and has a large aperture, and to reduce image deterioration such as ghost or flare caused due to unnecessary light.
Further, in the imaging lens according to the present embodiment, forming the lens surface closest to the image plane side (the lens surface, on the image plane side, of the seventh lens L7) in a shape of an aspherical surface having a concave shape near the optical axis and a convex shape at a peripheral part suppresses an incident angle of the light that has been outputted from the seventh lens L7, to the image plane IMG.
An imaging lens according to the present embodiment desirably satisfies the following conditional expression (1),
−0.5<f/f1<0.23 (1)
where f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens L1.
The above-described conditional expression (1) defines a ratio of the focal length of the first lens L1 to the focal length of a lens system as a whole.
If f/f1 exceeds the upper limit value of the conditional expression (1), the positive refractive power of the first lens L1 is too intense. For example, as illustrated in
It is to be noted that, in order to achieve, more favorably, an effect of the above-described conditional expression (1), a numerical range of the conditional expression (1) is desirably set as in the following conditional expression (1)′.
−0.20<f/f1<0.20 (1)′
In order to further achieve, more favorably, the effect of the above-described conditional expression (1), the numerical range of the conditional expression (1) is desirably set as in the following conditional expression (1)″.
−0.074<f/f1<0.092 (1)″
In an imaging lens according to the present embodiment, by satisfying the conditional expression (1)″, it is possible to reduce the veiling glare even with a large aperture and to ensure favorable resolution performance regardless of whether the lens surface, on the object side, of the first lens L1, the lens surface, on the image plane side, of the first lens L1, and the lens surface, on the object side, of the second lens L2 each are in a concave shape or in a convex shape near the optical axis.
Further, an imaging lens according to the present embodiment desirably satisfies the following further conditional expressions (2) and (3),
0<θmax(L1R1)<25 (2)
0.3<R(L3R2)/f<5 (3)
where θmax (L1R1) is a maximum value of a surface angle θ (L1R1) of the lens surface, on the object side, of the first lens L1 within an effective diameter, and
R(L3R2) is radius of curvature of the lens surface, on the image plane side, of the third lens L3.
The above-described conditional expression (2) defines the maximum inclination angle of the lens surface, on the object side, of the first lens L1. Further, the conditional expression (3) defines the ratio of curvature of the lens surface, on the image plane side, of the third lens L3 to the focal length of the lens system as a whole.
If θmax (L1R1) falls below the lower limit value of the conditional expression (2), the lens surface, on the object side, of the first lens L1 becomes concave on the object side, and the optical total length substantially becomes longer. This is unfavorable in size reduction. Further, if θmax (L1R1) exceeds the upper limit value of the conditional expression (2), the refractive power of the lens surface, on the object side, of the first lens L1 becomes intense. Thus, a portion of bundle of rays that has entered the lens surface, on the object side, of the first lens L1 is totally reflected on the lens surface, on the image plane side, of the third lens L3, further surface-reflected on the lens surface, on the object side, of the first lens L1, and, thereafter, reaches the image plane IMG. As a result, a veiling glare formed by light being condensed is caused on the image plane, as illustrated in
It is to be noted that, in order to further achieve, more favorably, the effect of the above-described conditional expression (2), the numerical range of the conditional expression (2) is desirably set as in the following conditional expression (2)′.
5<θmax(L1R1)<18 (2)′
Further, an imaging lens according to the present embodiment desirably satisfies the following further conditional expressions (4) and (5),
−15<θmin(L6R1)<θmax(L6R1)<8 (4)
−31<θmin(L6R2)<θmax(L6R2)<−5 (5)
where θmax (L6R1) is a maximum value of a surface angle θ (L6R1) of a lens surface, on the object side, of the sixth lens L6 within a diameter of 30% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmin (L6R1) is a minimum value of the surface angle θ (L6R1) of the lens surface, on the object side, of the sixth lens L6 within the diameter of 30% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmax (L6R2) is a maximum value of a surface angle θ (L6R2) of a lens surface, on the image plane side, of the sixth lens L6 within a diameter of 70% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”), and
θmin (L6R2) is a minimum value of the surface angle θ (L6R2) of the lens surface, on the image plane side, of the sixth lens L6 within the diameter of 70% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
The above-described conditional expression (4) defines a range of the maximum value of a surface angle θ (L6R1) of the lens surface, on the object side, of the sixth lens L6 within a diameter of 30% of an effective diameter.
The above-described conditional expression (5) defines a range of the maximum value of a surface angle θ (L6R2) of a lens surface, on the image plane side, of the sixth lens L6 within a diameter of 70% of an effective diameter. By satisfying the conditional expression (5), it is possible to ensure favorable performance. If θmax (L6R2) exceeds the upper limit value of the conditional expression (5), power of convexness of the lens surface, on the image plane side, of the sixth lens L6 is insufficient, which causes lack in correction power of off-axial coma aberration and leads to deterioration of image quality. Further, if θmax (L6R2) falls below the lower limit value of the conditional expression (5), a portion of an off-axial bundle of rays that has been surface-reflected on the lens surface, on the image plane side, of the sixth lens L6 is not outputted from the lens surface, on the object side, of the sixth lens L6 and totally reflected, totally reflected repeatedly within the sixth lens L6, thereafter, outputted from the lens surface, on the image plane side, of the sixth lens L6, and reaches the image plane IMG, as illustrated in
It is to be noted that, in order to achieve, more favorably, the effect of the above-described conditional expression (4), the numerical range of the conditional expression (4) is desirably set as in the following conditional expression (4)′.
−10<θmin(L6R1)<θmax(L6R1)<8 (4)′
In order to further achieve, more favorably, the effect of the above-described conditional expression (4), the numerical range of the conditional expression (4) is desirably set as in the following conditional expression (4)″.
−6<θmax(L6R1)<7 (4)″
In addition, the numerical range of the conditional expression (5) is desirably set as in the following conditional expression (5)′.
−22<θmin(L6R2)<θmax(L6R2)<−8 (5)′
In addition, an imaging lens according to the present embodiment desirably satisfies the following further conditional expression (6),
5<θmax(L3R2)<40 (6)
where θmax (L3R2) is a maximum value of a surface angle θ (L3R2) of the lens surface, on the image plane side, of the third lens L3 within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
The above-described conditional expression (6) defines a range of the maximum value of a surface angle θ (L3R2) of the lens surface, on the image plane side, of the third lens L3 within an effective diameter. By satisfying the conditional expression (6), it is possible to ensure favorable performance. If θmax (L3R2) falls below the lower limit value of the conditional expression (6), negative refractive power of the third lens L3 becomes weak, and it becomes difficult to favorably correct a spherical aberration or a coma aberration caused at the first lens L1 or the second lens L2. Further, if θmax (L3R2) exceeds the upper limit value of the conditional expression (6), the third lens L3 has excessive negative power, and it becomes difficult to correct the spherical aberration or the coma aberration. Furthermore, the surface angle is too large, which increases the degree of difficulty in manufacturing.
It is to be noted that, in order to achieve, more favorably, the effect of the above-described conditional expression (6), the numerical range of the conditional expression (6) is desirably set as in the following conditional expression (6)′.
15<θ(L3R2)<38 (6)′
Further, an imaging lens according to the present embodiment desirably satisfies the following further conditional expression (7),
0.3<f12/f<2.0 (7)
where f is a focal length of a lens system as a whole, and
f12 is a composite focal length of the first lens L1 and the second lens L2.
The conditional expression (7) defines the ratio of the composite focal length of the first lens L1 and the second lens L2 to the focal length of a lens system as a whole. By satisfying the conditional expression (7), it is possible to ensure favorable performance. If f12/f falls below the lower limit value of the conditional expression (7), composite power of the first lens L and the second lens L2 becomes too intense, and it becomes difficult to correct a spherical aberration, a coma aberration, or an astigmatism. Further, f12/f exceeds the upper limit value of the conditional expression (7), the composite power of the first lens L1 and the second lens L2 becomes too weak, and it is difficult to shorten the optical total length.
It is to be noted that, in order to achieve, more favorably an effect of the above-described conditional expression (7), a numerical range of the conditional expression (7) is desirably set as in the following conditional expression (7)′.
0.5<f12/f<1.5 (7)′
In addition, an imaging lens according to the present embodiment desirably satisfies the following further conditional expression (8),
−5<f3/f<−0.5 (8)
where f is a focal length of a lens system as a whole, and
f3 is a focal length of the third lens L3.
The above-described conditional expression (8) defines the ratio of the focal length of the third lens L3 to the focal length of a lens system as a whole. By satisfying the conditional expression (8), it is possible to ensure favorable performance. If f3/f falls below the lower limit value of the conditional expression (8), negative refractive power of the third lens L3 becomes weak, and it becomes difficult to favorably correct an on-axial chromatic aberration generated at the second lens L2. Further, if f3/f exceeds the upper limit value of the conditional expression (8), negative refractive power of the third lens L3 becomes too intense, it becomes difficult to shorten the optical total length.
It is to be noted that, in order to achieve, more favorably, an effect of the above-described conditional expression (8), a numerical range of the conditional expression (8) is desirably set as in the following conditional expression (8)′.
−3.5<f3/f<−1.0 (8)′
In addition, an imaging lens according to the present embodiment desirably satisfies the following further conditional expression (9),
0.023<T(L3)/f<0.15 (9)
where f is a focal length of a lens system as a whole, and
T (L3) is a center thickness of the third lens L3.
The above-described conditional expression (9) defines the ratio of a center thickness of the third lens L3 to the focal length of a lens system as a whole. If the third lens L3 has a thinner center thickness, it becomes difficult to mold a lens due to a concave meniscus shape while it becomes easy to correct a coma aberration. By allowing T(L3)/f to fall within the range of the conditional expression (9), it is possible to favorably maintain a coma aberration, and the formation becomes easy.
It is to be noted that, in order to achieve, more favorably, an effect of the above-described conditional expression (9), a numerical range of the conditional expression (9) is desirably set as in the following conditional expression (9)′.
0.045<T(L3)/f<0.1 (9)′
In addition, an imaging lens according to the present embodiment desirably satisfies the following further conditional expression (10),
νd(L1)>50 (10)
where νd (L1) is Abbe number of the first lens L1 to d line.
In addition, an imaging lens according to the present embodiment desirably satisfies the following further conditional expressions (11) and (12).
νd(L3)<35 (11)
νd(L5)<35 (12)
where νd (L3) is Abbe number of the third lens L3 to d line, and
νd (L5) is Abbe number of the fifth lens L5 to d line.
The above-described conditional expression (10) defines Abbe number of a glass material of the first lens L1 to d line. Further, the above-described conditional expressions (11) and (12) respectively define Abbe number of glass materials of the third lens L3 and the fifth lens L5 to d line. By satisfying the conditional expressions (10), and (11) and (12), it is possible to ensure favorable performance with a low profile. Abbe numbers of the third lens L3 and the fifth lens L5 respectively fall below the upper limit value of the conditional expressions (11) and (12), which thereby makes it possible to improve a correction effect of a chromatic aberration by the third lens L3 and the fifth lens L5.
In addition, an imaging lens according to the present embodiment desirably satisfies the following further conditional expressions (13), (14), and (15),
νd(L4)>50 (13)
νd(L6)>50 (14)
νd(L7)>50 (15)
where νd (L4) is Abbe number of the fourth lens L4 to d line,
νd (L6) is Abbe number of the sixth lens L6 to d line, and
νd (L7) is Abbe number of the seventh lens L7 to d line.
The conditional expressions (13), (14), and (15) respectively define Abbe numbers of glass materials of the fourth lens L4, the sixth lens L6, and the seventh lens L7 to d line. By satisfying the conditional expressions (13), (14), and (15), it is possible to ensure favorable performance with a low profile. Abbe numbers of the sixth lens L6 and the seventh lens L7 exceed the lower limit value of the conditional expressions (13), (14), and (15), which thereby makes it possible to improve a correction effect of a chromatic aberration.
Next, an application example of an imaging lens according to the present embodiment to an imaging apparatus is described.
For example, the display section 202 is a touch panel that detects a contact state to a surface to allow for various kinds of operation. Therefore, the display section 202 has a display function of displaying various kinds of information and an input function of allowing for various kinds of input operation by a user. The display section 202 displays, for example, an operation state and various kinds of data such as an image photographed by the front camera section 203 or the main camera section 204.
For example, the imaging lens according to the present embodiment is applicable as a camera module lens of the imaging apparatus (the front camera section 203 or the main camera section 204) in the mobile terminal apparatus as illustrated in
It is noted that the imaging lens according to the present embodiment is not limited to the above-described mobile terminal apparatus but is applicable as an imaging lens of other electronic apparatuses such as a digital still camera and a digital video camera. In addition, the imaging lens according to the present embodiment is applicable to general small imaging apparatuses using a solid-state imaging device such as a CCD and a CMOS. Such small imaging apparatuses include, for example, an optical sensor, a mobile module camera, and a WEB camera. Further, such small imaging apparatuses also include a monitoring camera, for example.
Next, specific numerical examples of an imaging lens according to the present embodiment are described. Numerical Examples in which specific values are applied to the imaging lenses 1 to 19 in the respective configuration examples respectively illustrated in
It is to be noted that meanings, etc. of respective symbols indicated in the following tables and descriptions are as described below. “Si” indicates number of the i-th surface that is counted from the side closest to the object side. “Ri” indicates a value (mm) of paraxial radius of curvature of the i-th surface. “Di” indicates a value (mm) of a spacing on the optical axis between the i-th surface and the (i+1)th surface. “Ndi” indicates a value of a refractive index in d line (wavelength of 587.6 nm) of a material of an optical element having the i-th surface. “νdi” indicates a value of Abbe number in the d line of the material of the optical element having the i-th surface. A portion at which a value of “Ri” is “∞” is a flat surface, or a virtual surface. “Li” indicates a property of a surface. A surface denoted as “OBJ” in “Li” indicates an object surface. In “Li”, for example, “L1R1” indicates a lens surface, on the object side, of the first lens L1, and “L1R2” indicates a lens surface, on the image plane side, of the first lens L1. Similarly, in “Li”, “L2R1” indicates a lens surface, on the object side, of the second lens L2, and “L2R2” indicates a lens surface, on the image plane side, of the second lens L2. The same applies to other lens surfaces as well.
In “Si”, a surface denoted as “ASP” indicates an aspherical surface. The aspherical shape is defined by the following expression. It is to be noted that, in the respective tables showing aspherical surface coefficients described later, “E-i” represents an exponential expression having 10 as a base, i.e., “10−i”. For example, “0.12345E-05” represents “0.12345×10−5”.
Z=C·h
2/{1+(1−(1+K)·C2·h2)1/2}+ΣAn·hn
(n is an integer of no less than three)
where Z is a depth of the aspherical surface,
C is a paraxial curvature that is equal to 1/R,
h is a distance from the optical axis to the lens surface,
K is an eccentricity (second-order aspherical surface coefficient), and
An is an n-th order aspherical surface coefficient.
Any of the imaging lenses 1 to 19 to which respective numerical examples below are applied has a configuration that satisfies the above-described basic configuration of the lens. In other words, any of the imaging lenses 1 to 19 substantially includes seven lenses in which the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are disposed in order from the object side toward the image plane side.
The first lens L1 has a meniscus shape. The meniscus shape has a shape that is positioned near an optical axis and includes a convex surface that faces the object side. The second lens L2 includes a convex surface that faces, near the optical axis, the object side. The seventh lens L7 includes a lens surface. The lens surface is positioned on image plane side and has an aspherical shape that has an inflection point that changes a concave-convex shape in the middle thereof, as it goes from a center part to a peripheral part.
The aperture stop St is disposed between the lens surface, on the image plane side, of the first lens L1 and the lens surface, on the image plane side, of the second lens L2. The seal glass SG is disposed between the seventh lens L7 and the image plane IMG.
Table 1 shows basic lens data of Numerical Example 1 in which specific numerical values are applied to the imaging lens 1 illustrated in
In the imaging lens 1 according to Numerical Example 1, both surfaces of each of the first lens L to the seventh lens L7 have aspherical shapes. Table 2 and Table 3 show values of coefficients representing these aspherical shapes.
In the imaging lens 1 according to Numerical Example 1, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 1 above are illustrated in
As can be appreciated from the respective aberration diagrams, it is clear that, in the imaging lens 1 according to Numerical Example 1, the various aberrations are favorably corrected while the lens is small-sized, and excellent optical performance is achieved.
Table 4 shows basic lens data of Numerical Example 2 in which specific numerical values are applied to the imaging lens 2 illustrated in
In the imaging lens 2 according to Numerical Example 2, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 5 and Table 6 show values of coefficients representing these aspherical shapes.
In the imaging lens 2 according to Numerical Example 2, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 2 above are illustrated in
Table 7 shows basic lens data of Numerical Example 3 in which specific numerical values are applied to the imaging lens 3 illustrated in
In the imaging lens 3 according to Numerical Example 3, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 8 and Table 9 show values of coefficients representing these aspherical shapes.
In the imaging lens 3 according to Numerical Example 3, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has positive refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 3 above are illustrated in
Table 10 shows basic lens data of Numerical Example 4 in which specific numerical values are applied to the imaging lens 4 illustrated in
In the imaging lens 4 according to Numerical Example 4, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 11 and Table 12 show values of coefficients representing these aspherical shapes.
In the imaging lens 4 according to Numerical Example 4, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 4 above are illustrated in
Table 13 shows basic lens data of Numerical Example 5 in which specific numerical values are applied to the imaging lens 5 illustrated in
In the imaging lens 5 according to Numerical Example 5, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 14 and Table 15 show values of coefficients representing these aspherical shapes.
In the imaging lens 5 according to Numerical Example 5, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 5 above are illustrated in
Table 16 shows basic lens data of Numerical Example 6 in which specific numerical values are applied to the imaging lens 6 illustrated in
In the imaging lens 6 according to Numerical Example 6, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 17 and Table 18 show values of coefficients representing these aspherical shapes.
In the imaging lens 6 according to Numerical Example 6, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has positive refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 6 above are illustrated in
Table 19 shows basic lens data of Numerical Example 7 in which specific numerical values are applied to the imaging lens 7 illustrated in
In the imaging lens 7 according to Numerical Example 7, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 20 and Table 21 show values of coefficients representing these aspherical shapes.
In the imaging lens 7 according to Numerical Example 7, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has positive refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 7 above are illustrated in
Table 22 shows basic lens data of Numerical Example 8 in which specific numerical values are applied to the imaging lens 8 illustrated in
In the imaging lens 8 according to Numerical Example 8, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 23 and Table 24 show values of coefficients representing these aspherical shapes.
In the imaging lens 8 according to Numerical Example 8, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 8 above are illustrated in
Table 25 shows basic lens data of Numerical Example 9 in which specific numerical values are applied to the imaging lens 9 illustrated in
In the imaging lens 9 according to Numerical Example 9, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 26 and Table 27 show values of coefficients representing these aspherical shapes.
In the imaging lens 9 according to Numerical Example 9, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 9 above are illustrated in
Table 28 shows basic lens data of Numerical Example 10 in which specific numerical values are applied to the imaging lens 10 illustrated in
In the imaging lens 10 according to Numerical Example 10, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 29 and Table 30 show values of coefficients representing these aspherical shapes.
In the imaging lens 10 according to Numerical Example 10, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 10 above are illustrated in
Table 31 shows basic lens data of Numerical Example 11 in which specific numerical values are applied to the imaging lens 11 illustrated in
In the imaging lens 11 according to Numerical Example 11, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 32 and Table 33 show values of coefficients representing these aspherical shapes.
In the imaging lens 11 according to Numerical Example 11, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 11 above are illustrated in
Table 34 shows basic lens data of Numerical Example 12 in which specific numerical values are applied to the imaging lens 12 illustrated in
In the imaging lens 12 according to Numerical Example 12, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 35 and Table 36 show values of coefficients representing these aspherical shapes.
In the imaging lens 12 according to Numerical Example 12, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has positive refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 12 above are illustrated in
Table 37 shows basic lens data of Numerical Example 13 in which specific numerical values are applied to the imaging lens 13 illustrated in
In the imaging lens 13 according to Numerical Example 13, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 38 and Table 39 show values of coefficients representing these aspherical shapes.
In the imaging lens 13 according to Numerical Example 13, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 13 above are illustrated in
Table 40 shows basic lens data of Numerical Example 14 in which specific numerical values are applied to the imaging lens 14 illustrated in
In the imaging lens 14 according to Numerical Example 14, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 41 and Table 42 show values of coefficients representing these aspherical shapes.
In the imaging lens 14 according to Numerical Example 14, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 14 above are illustrated in
Table 43 shows basic lens data of Numerical Example 15 in which specific numerical values are applied to the imaging lens 15 illustrated in
In the imaging lens 15 according to Numerical Example 15, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 44 and Table 45 show values of coefficients representing these aspherical shapes.
In the imaging lens 15 according to Numerical Example 15, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 15 above are illustrated in
Table 46 shows basic lens data of Numerical Example 16 in which specific numerical values are applied to the imaging lens 16 illustrated in
In the imaging lens 16 according to Numerical Example 16, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 47 and Table 48 show values of coefficients representing these aspherical shapes.
In the imaging lens 16 according to Numerical Example 16, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 16 above are illustrated in
Table 49 shows basic lens data of Numerical Example 17 in which specific numerical values are applied to the imaging lens 17 illustrated in
In the imaging lens 17 according to Numerical Example 17, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 50 and Table 51 show values of coefficients representing these aspherical shapes.
In the imaging lens 17 according to Numerical Example 17, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 17 above are illustrated in
Table 52 shows basic lens data of Numerical Example 18 in which specific numerical values are applied to the imaging lens 18 illustrated in
In the imaging lens 18 according to Numerical Example 18, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 53 and Table 54 show values of coefficients representing these aspherical shapes.
In the imaging lens 18 according to Numerical Example 18, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has positive refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 18 above are illustrated in
Table 55 shows basic lens data of Numerical Example 19 in which specific numerical values are applied to the imaging lens 19 illustrated in
In the imaging lens 19 according to Numerical Example 19, both surfaces of each of the first lens L1 to the seventh lens L7 have aspherical shapes. Table 56 and Table 57 show values of coefficients representing these aspherical shapes.
In the imaging lens 19 according to Numerical Example 19, the first lens L1 has positive refractive power near the optical axis. The second lens L2 has positive refractive power near the optical axis. The third lens L3 has negative refractive power near the optical axis. The fourth lens L4 has negative refractive power near the optical axis. The fifth lens L5 has negative refractive power near the optical axis. The sixth lens L6 has positive refractive power near the optical axis. The seventh lens L7 has negative refractive power near the optical axis.
Various aberrations in Numerical example 19 above are illustrated in
Table 58 shows a summarization, for each of Numerical Examples, of a focal length of a lens system as a whole f, an F value, a half angle of view ω, and values of the respective focal lengths f1, f2, f3, f4, f5, f6, and f7 of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.
Further, Table 59 and Table 60 each show a summarization, for each of Numerical Examples, of values relating to the above-described respective conditional expressions. It is to be noted that Example 18 falls outside the range of conditional expression (2).
A technique of the present disclosure is not limited to the above description of the embodiments and the examples, and may be variously modified.
For example, the shapes of the respective sections and the numerical values illustrated in the above-described Numerical Examples are merely illustrative for carrying out the technology, and should not be used to construe the technical scope of the technology in a limitative manner.
In addition, the configuration substantially including seven lenses has been described in the embodiment and the examples described above; however, a configuration further including a lens that does not have refractive power substantially is adoptable.
Further, the technology may achieve the following configuration, for example.
[1]
An imaging lens including, in order from object side toward image plane side:
a first lens having a meniscus shape, the meniscus shape having a shape that is positioned near an optical axis and includes a convex surface that faces the object side;
a second lens including a convex surface that faces, near the optical axis, the object side, and having, near the optical axis, positive refractive power;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point.
[2]
The imaging lens according to [1], in which a following conditional expression is satisfied:
−0.5<f/f1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.
[3]
The imaging lens according to [1] or [2], in which following conditional expressions are satisfied:
0<θmax(L1R1)<25 (2)
0.3<R(L3R2)/f<5 (3)
where
θmax (L1R1) is a maximum value of a surface angle of a lens surface, on the object side, of the first lens within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
R (L3R2) is radius of curvature of a lens surface, on the image plane side, of the third lens, and
f is a focal length of a lens system as a whole.
[4]
The imaging lens according to any one of [1] to [3], in which following conditional expressions are satisfied:
−15<θmin(L6R1)<θmax(L6R1)<8 (4)
−31<θmin(L6R2)<θmax(L6R2)<−5 (5)
where
θmax (L6R1) is a maximum value of a surface angle of a lens surface, on the object side, of the sixth lens within a diameter of 30% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmin (L6R1) is a minimum value of the surface angle of the lens surface, on the object side, of the sixth lens within the diameter of 30% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmax (L6R2) is a maximum value of a surface angle of a lens surface, on the image plane side, of the sixth lens within a diameter of 70% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”), and
θmin (L6R2) is a minimum value of the surface angle of the lens surface, on the image plane side, of the sixth lens within the diameter of 70% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
[5]
The imaging lens according to any one of [1] to [4], in which a following conditional expression is satisfied:
5<θmax(L3R2)<40 (6)
where
θmax (L3R2) is a maximum value of a surface angle of a lens surface, on the image plane side, of the third lens within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
[6]
The imaging lens according to any one of [1] to [5], in which a following conditional expression is satisfied:
0.3<f12/f<2.0 (7)
where
f is a focal length of a lens system as a whole, and
f12 is a composite focal length of the first lens and the second lens.
[7]
The imaging lens according to any one of [1] to [6], in which a following conditional expression is satisfied:
−5<f3/f<−0.5 (8)
where
f is a focal length of a lens system as a whole, and
f3 is a focal length of the third lens.
[8]
The imaging lens according to any one of [1] to [7], in which a following conditional expression is satisfied:
0.023<T(L3)/f<0.15 (9)
where
f is a focal length of a lens system as a whole, and
T(L3) is a center thickness of the third lens.
[9]
The imaging lens according to any one of [1] to [9], in which a following conditional expression is satisfied:
νd(L1)>50 (10)
where
νd (L1) is Abbe number of the first lens to d line.
[10]
The imaging lens according to any one of [1] to [10], in which following conditional expressions are satisfied:
νd(L3)<35 (11)
νd(L5)<35 (12)
where
νd (L3) is Abbe number of the third lens to d line, and
νd (L5) is Abbe number of the fifth lens to the d line.
[11]
The imaging lens according to any one of [1] to [11], in which following conditional expressions are satisfied:
νd(L4)>50 (13),
νd(L6)>50 (14)
νd(L7)>50 (15).
where
νd (L4) is Abbe number of the fourth lens to d line,
νd (L6) is Abbe number of the sixth lens to the d line, and
νd (L7) is Abbe number of the seventh lens to the d line.
[12]
An imaging lens including, in order from object side toward image plane side:
a first lens;
a second lens having, near an optical axis, positive refractive power;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens that having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point,
in which a following conditional expression is satisfied,
−0.5<f/f1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.
[13]
The imaging lens according to [12], in which a following conditional expression is satisfied:
0.3<R(L3R2)/f<5 (3)
where
R (L3R2) is radius of curvature of a lens surface, on the image plane side, of the third lens, and
f is the focal length of the lens system as a whole.
[14]
The imaging lens according to [12] or [13], in which following conditional expressions are satisfied:
−15<θmin(L6R1)<θmax(L6R1)<8 (4)
−31<θmin(L6R2)<θmax(L6R2)<−5 (5)
where
θmax (L6R1) is a maximum value of a surface angle of a lens surface, on the object side, of the sixth lens within a diameter of 30% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”),
θmin (L6R1) is a minimum value of the surface angle of the lens surface, on the object side, of the sixth lens within the diameter of 30% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
θmax (L6R2) is a maximum value of a surface angle of a lens surface, on the image plane side, of the sixth lens within a diameter of 70% of an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”), and
θmin (L6R2) is a minimum value of the surface angle of the lens surface, on the image plane side, of the sixth lens within the diameter of 70% of the effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
[15]
The imaging lens according to any one of [12] to [14], in which a following conditional expression is satisfied:
5<θmax(L3R2)<40 (6)
where
θmax (L3R2) is a maximum value of a surface angle of a lens surface, on the image plane side, of the third lens within an effective diameter (where inclination of the lens surface toward the image plane side is defined as positive, and where a unit is “degree”).
[16]
The imaging lens according to any one of [12] to [15], in which a following conditional expression is satisfied:
0.3<f12/f<2.0 (7)
where
f is the focal length of the lens system as a whole, and
f12 is a composite focal length of the first lens and the second lens.
[17]
The imaging lens according to any one of [12] to [16], in which a following conditional expression is satisfied:
−5<f3/f<−0.5 (8)
where
f is the focal length of the lens system as a whole, and
f3 is a focal length of the third lens.
[18]
The imaging lens according to any one of [12] to [17], in which a following conditional expression is satisfied:
0.023<T(L3)/f<0.15 (9)
where
f is the focal length of the lens system as a whole, and
T (L3) is a center thickness of the third lens.
[19]
The imaging lens according to any one of [1] to [18], further including a lens that does not substantially have refractive power.
[20]
An imaging apparatus provided with an imaging lens and an imaging device that outputs an imaging signal corresponding to an optical image formed by the imaging lens, the imaging lens including, in order from object side toward image plane side:
a first lens having a meniscus shape, the meniscus shape having a shape that is positioned near an optical axis and includes a convex surface that faces the object side;
a second lens including a convex surface that faces, near the optical axis, the object side, and having, positive refractive power near the optical axis;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point.
[21]
An imaging apparatus provided with an imaging lens and an imaging device that outputs an imaging signal corresponding to an optical image formed by the imaging lens, the imaging lens including, in order from object side toward image plane side:
a first lens;
a second lens having, near the optical axis, positive refractive power;
a third lens having, near the optical axis, negative refractive power;
a fourth lens;
a fifth lens;
a sixth lens having, near the optical axis, positive refractive power; and
a seventh lens having, near the optical axis, negative refractive power, and including a lens surface, the lens surface being positioned on the image plane side and having an aspherical shape that has an inflection point,
in which a following conditional expression is satisfied,
−0.5<f/f1<0.23 (1)
where
f is a focal length of a lens system as a whole, and
f1 is a focal length of the first lens.
[22]
The imaging apparatus according to [20] or [21], in which the imaging lens further includes a lens that does not substantially have refractive power.
This application is based upon and claims the benefit of priority of the Japanese Patent Application No. 2016-100377 filed with the Japan Patent Office on May 19, 2016, the entire contents of which are incorporated herein by reference.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-100377 | May 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/014504 | 4/7/2017 | WO | 00 |
