WO2012173026A1 - Image capture lens for image capture device and image capture device - Google Patents

Abstract

Provided are an image capture lens which offers high-quality images while having a two-layer configuration, and an image capture device employing same. In a two-layer configuration image capture lens, with the value r2/f exceeding the lower bound of the formula (1), the radius of curvature of the image-side face of the first lens cannot be made too small and overcompensation on the image capture surface which is curved on the periphery thereof may be prevented. Additionally, the focal length of the first lens increases, thereby bringing the forward principal point location closer to the image surface, increasing the image capture lens optical length, and complicating miniaturization. Conversely, with the value r2/f falling below the upper bound of the formula (1), the radius of curvature cannot be made too large, a high image height light beam may be projected therefrom, and an incident angle of a primary light beam upon the periphery may be appropriately set. Additionally, the Petzval sum does not get too large with respect to a solid state image capture element which is curved on the periphery thereof, and it is thus possible to obtain good image surface performance out to the screen periphery part. 0.40<r2/f<4.0 (1) where r2 is the radius of curvature of the first lens image side surface, and f is the focal length of the total assembly.

Description

Imaging lens and imaging device for imaging device

The present invention relates to an imaging lens and an imaging device for an imaging device, and in particular, the present invention is a solid-state imaging device such as a CCD type image sensor or a CMOS type image sensor and suitable for a solid-state imaging device having a curved imaging surface. The present invention relates to an imaging lens and an imaging apparatus using the imaging lens.

In recent years, with the improvement in performance and miniaturization of image sensors using solid-state image sensors such as CCD (Charge Coupled Device) image sensors or CMOS (Complementary Metal Oxide Semiconductor) image sensors, Portable information terminals are widespread. Imaging lenses mounted on these imaging apparatuses are required to be further reduced in size and higher in image quality. In addition to portable terminals, the use of small-sized imaging devices is expanding, and imaging devices mounted on or attached to so-called flat-screen TVs and PC displays using liquid crystal technology, as well as in-vehicle devices for drive recorders and back monitors. Expansion to imaging devices and the like is expected. In particular, portable information devices such as smartphones and tablet computers, which have rapidly spread in recent years, are equipped with large-sized displays and are thin and excellent in portability. It is demanded.

As a lens for an imaging apparatus for such a use, a lens having one or two lenses is widely used because it is advantageous for downsizing and cost reduction. However, due to the recent demand for higher image quality by increasing the number of pixels in the image sensor, the two-lens imaging lens lacks the ability to correct aberrations and is insufficient to form a high-quality image. On the other hand, if the imaging lens is composed of three or more lenses, the optical performance is improved. However, the total length of the lens is increased and the cost is increased accordingly.

On the other hand, as a technique for improving the image plane performance without relying on a lens, an imaging apparatus that curves the imaging plane has also been developed. For example, Patent Document 1 discloses that a solid-state imaging device can be curved into a polynomial surface shape to correct the curvature of field and distortion generated by a lens in a well-balanced manner, thereby providing a compact and high-resolution imaging apparatus. . However, in Patent Document 1, since the solid-state imaging device has a CIF size (352 pixels × 288 pixels), the imaging lens has a single lens configuration, and chromatic aberration is not sufficiently corrected, a solid-state imaging device having a higher pixel is used. Therefore, it is not possible to obtain an imaging device having high performance.

Further, Patent Document 2 discloses that a subject image is formed on a curved surface, but here the imaging target is assumed to be both a silver salt film and a solid-state image sensor, and the optical total length Is not taken into consideration in terms of shortening. Due to the structure of a camera using a roll film, the distance between the lens and the imaging surface must be wide, and as a result, the camera lens described in Patent Document 2 has not been sufficiently shortened in optical length. Furthermore, the camera lens of Patent Document 2 has a dark F value of F10 or more, and in recent years, the light receiving area per pixel tends to be reduced due to the increase in the density of solid-state imaging devices. It could not be said that it has a lens.

Further, Patent Document 3 includes an image pickup optical system device that includes an image pickup element whose electronic image pickup surface is formed in a concave shape in a cross section including the optical axis, and that can properly correct field curvature using two lenses. Is described. However, although the lens disclosed in Patent Document 3 has a bright F value, in order to obtain a so-called telecentric characteristic of a chief ray incident angle of a light beam incident on the imaging surface, the distance between the lens and the imaging surface is wide. The shortening of the optical total length was insufficient.

JP 2004-356175 A JP-A-8-334684 JP 2004-118077 A

The present invention has been made in view of the above problems, and has a two-element configuration with respect to a solid-state imaging device having a curved imaging surface, and has a bright F value, a short optical system overall length, and high image quality. An object of the present invention is to provide an obtained imaging lens and an imaging device using the imaging lens.

Here, although it is a scale of a small imaging lens, the present invention aims at miniaturization at a level satisfying the following expression. By satisfying this range, the entire imaging apparatus can be reduced in size and weight.
L / 2Y <1.1 (10)
However,
L: Distance on the optical axis from the lens surface closest to the object side to the image-side focal point of the entire imaging lens system 2Y: diagonal length along the imaging surface of the solid-state imaging device (on the imaging surface of the rectangular effective pixel region of the solid-state imaging device) Diagonal length along)

Here, the image-side focal point refers to an image point when a parallel light beam parallel to the optical axis is incident on the imaging lens. When a parallel plate such as an optical low-pass filter, an infrared cut filter, or a seal glass of a solid-state image sensor package is disposed between the image-side surface of the imaging lens and the image-side focal position, the imaging lens is parallel. The flat plate portion is calculated as the above L value after the air conversion distance. More preferably, the range of the following formula is good.
L / 2Y <1.0 (10 ′)

The imaging lens according to claim 1 is an imaging lens for forming a subject image on an imaging surface of a solid-state imaging device that is curved three-dimensionally about an optical axis, and is provided on the object side and is a positive lens. A first meniscus lens having a refractive power and convex toward the object side; a second lens having a positive or negative refractive power provided on the image side; and an aperture stop provided on the object side from the second lens. Thus, the following conditional expression is satisfied.
0.40 <r2 / f <4.0 (1)
However,
r2: radius of curvature of the image side surface of the first lens f: focal length of the entire system

In general, in the case of a solid-state imaging device, it is often necessary to keep the principal ray incident angle of a light beam incident on the imaging surface to 30 ° or less. The light beam was strongly bent in the vicinity of the lens, which was one of the causes of the deterioration of lateral chromatic aberration. On the other hand, by attaching a negative curvature to the imaging surface (that is, three-dimensionally curving so that the peripheral side of the imaging surface falls to the object side), the chief ray incident angle is naturally relaxed, Chromatic aberration is improved because it is not necessary to bend the light at the peripheral image height. In addition, both the short side direction and long side direction of the imaging surface have a curved surface on the object side around the imaging surface, which degrades the optical performance caused by the difference in curvature between the short side and long side of the imaging surface, which occurs in a cylindrical manner. Can be suppressed. As a result, a high-quality image can be formed even with a two-lens imaging lens with relatively low aberration correction performance.

Furthermore, compared to the case where the imaging surface is flat as described above, the chief ray incident angle of the light beam incident on the imaging surface is likely to have a so-called telecentric characteristic, but if the exit pupil is too close to the imaging surface, a sufficient angle is obtained. Can't get. On the other hand, if an aperture is placed behind the image side surface of the second lens to maintain the telecentric characteristics, sufficient back focus must be obtained, which is not suitable for miniaturization. For this reason, an aperture stop is provided on the object side of the second lens, and the distance between the imaging surface and the exit pupil is maintained appropriately by separating the aperture position from the imaging surface like a so-called front diaphragm or middle diaphragm. It is possible to maintain the telecentric characteristic.

The basic configuration of this patent consists of a first lens having a positive refractive power and a convex meniscus shape on the object side, and a second lens having a positive or negative refractive power. When the value r2 / f exceeds the lower limit value of the conditional expression (1), the curvature radius of the image side surface of the first lens does not become too small, and overcorrection is prevented with respect to the imaging surface curved toward the object side at the periphery. I can do it. In addition, since the focal length of the first lens does not become too long and the front principal point position approaches the object side, the optical length of the imaging lens does not become long and the size can be reduced.

On the other hand, when the value r2 / f is lower than the upper limit value of the conditional expression (1), the radius of curvature does not become too large, and a high image height light beam can be sufficiently jumped, and the incident angle of the principal ray at the periphery Can be set appropriately. Further, since the Petzval sum does not become too large with respect to the solid-state imaging device curved at the periphery, it is possible to obtain good image surface performance up to the periphery of the screen. More preferably, the range of the following formula is good.
0.45 <r2 / f <3.6 (1) ′

The imaging lens described in claim 2 is characterized in that, in the invention described in claim 1, the following conditional expression is satisfied.
0.15 <PTZ <0.40 (2)
However,
PTZ: Petzval sum of the first lens and the second lens

Conditional expression (2) is an expression (Petzbar sum) representing the relationship between a planar object and the curvature of field with respect to the plane object, and in order to suppress the curvature of field, the combination of the focal length of each lens and the refractive power of the lens material It is desirable to optimize. When the solid-state imaging device is a flat surface, the Petzval sum is required to be small. However, in a two-lens configuration, since the number of optical surfaces is small, if the Petzval sum is kept small, the degree of curvature of the lens is lost and correction of spherical aberration and chromatic aberration becomes insufficient. There is a fear.

Therefore, since the Petzval sum does not become too small by making the value of conditional expression (2) exceed the lower limit, the amount of curvature toward the object side around the image plane of the optical system is maintained, and at the same time Aberration and chromatic aberration can be corrected. On the other hand, by setting the value of conditional expression (2) below the upper limit value, the periphery of the image plane of the optical system is not excessively curved toward the object side, which is favorable for the image plane around the solid-state imaging device. Image surface performance can be obtained. More preferably, the range of the following formula is good.
0.18 <PTZ <0.35 (2) ′

The imaging lens described in claim 3 is characterized in that, in the invention described in claim 1 or 2, the following conditional expression is satisfied.
0.30 <d3 / f <2.60 (3)
However,
d3: Core thickness of the second lens

Conditional expression (3) is a conditional expression that determines the core thickness of the second lens. By making the value of conditional expression (3) exceed the lower limit value, the light flux for each image height can be sufficiently separated in the second lens. Aberration correction becomes easier. On the other hand, an imaging lens can be reduced in size by making the value of conditional expression (3) fall below an upper limit. More preferably, the range of the following formula is good.
0.36 <d3 / f <2.30 (3) ′

An imaging lens according to a fourth aspect of the invention is characterized in that, in the invention according to any one of the first to third aspects, the following conditional expression is satisfied.
0.30 <r1 / f <2.30 (4)
However,
r1: radius of curvature of the object side surface of the first lens

Conditional expression (4) is a conditional expression that determines the radius of curvature of the object side surface of the first lens. When the value of conditional expression (4) is less than the upper limit value, the refractive power of the object side surface of the first lens can be appropriately maintained, and the composite principal point of the first lens and the second lens is arranged on the object side. And the entire length of the imaging lens can be shortened. On the other hand, when the value of conditional expression (4) exceeds the lower limit value, the refractive power of the first lens object side surface does not become excessively large, and higher-order spherical aberration and coma aberration generated in the first lens are reduced. It can be kept small. More preferably, the range of the following formula is good.
0.32 <r1 / f <2.03 (4) ′

The imaging lens described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the following conditional expression is satisfied.
0.10 <fB / TL <0.60 (5)
However,
fB: Distance between the image side surface of the second lens and the solid-state imaging device TL: Total lens length

Conditional expression (5) is a conditional expression that determines the distance between the second lens and the imaging surface. When the value of conditional expression (5) exceeds the lower limit value, a sufficient interval for inserting the infrared cut filter or the cover glass of the sensor can be secured. Since the distance between the second lens and the imaging surface can be prevented from being shortened, an increase in the diameter of the second lens can be prevented. On the other hand, when the value of conditional expression (5) is less than the upper limit value, the distance between the second lens and the imaging surface does not become too long, and the size can be reduced. The range of the following formula is more desirable.
0.15 <fB / TL <0.55 (5) ′

The imaging lens described in claim 6 is characterized in that, in the invention described in any one of claims 1 to 5, the following conditional expression is satisfied.
−0.38 <Y / rI <−0.01 (6)
However,
rI: radius of curvature of the imaging surface Y: maximum image height

Conditional expression (6) is a conditional expression that determines the amount of bending when the imaging surface is defined by the radius of curvature. When the value of conditional expression (6) exceeds the lower limit value, the amount of bending can be appropriately maintained, so that necessary telecentric characteristics can be obtained. On the other hand, when the value of conditional expression (6) is less than the upper limit value, the amount of curvature that protrudes toward the object side at the periphery of the imaging surface of the solid-state imaging device does not become too large, and the optical axis of the imaging lens and the center of the individual imaging device Since performance degradation due to deviation can be reduced, performance degradation during mass production is reduced. More preferably, the range of the following formula is good.
−0.34 <Y / rI <−0.07 (6) ′

An imaging lens according to a seventh aspect is characterized in that, in the invention according to any one of the first to sixth aspects, the following conditional expression is satisfied.
ν1> 30 (7)
However,
ν1: Abbe number of the first lens

Conditional expression (7) is a conditional expression that determines the Abbe number of the material of the first lens. When the value of conditional expression (7) exceeds the lower limit value, axial chromatic aberration can be kept small, and the image side surface of the first lens is a divergent surface, so that the peripheral portion of the screen is caused by a large amount of light rays from the periphery. Chromatic aberration of magnification can be reduced. More preferably, the range of the following formula is good.
ν1> 34 (7) '

An imaging lens according to an eighth aspect is characterized in that, in the invention according to any one of the first to seventh aspects, the following conditional expression is satisfied.
n1> 1.40 and n2> 1.40 (8)
However,
n1: Refractive index of the first lens n2: Refractive index of the second lens

Conditional expression (8) is a conditional expression that determines the refractive indexes of the materials of the first lens and the second lens. When the value of conditional expression (8) exceeds the lower limit, the Petzval sum does not become too large, so that it can be adjusted to the imaging surface of the curved solid-state imaging device. In addition, since the curvature at the lens periphery does not become excessively strong, the lateral chromatic aberration at the periphery of the screen can be reduced. More preferably, the range of the following formula is good.
n1> 1.49 and n2> 1.49 (8) ′

An imaging lens according to a ninth aspect is the invention according to any one of the first to sixth aspects, wherein at least one of the first lens and the second lens is a substrate and a lens portion formed on the substrate. It is a lens provided with.

By using at least one of the first lens and the second lens as a lens having a lens portion formed on a flat substrate (resin or glass), a material constituting the object side surface and the image side surface of each lens portion is used. Since it can be changed, chromatic aberration and image surface can be improved. In addition, such a lens can be manufactured by molding a large number of lens parts at once on a substrate (resin or glass) and then cutting them into individual pieces, thus reducing costs. I can do it. Such a lens can be formed using, for example, a manufacturing method described in Japanese Patent Application Laid-Open No. 2011-028213.

The image pickup lens described in claim 10 is characterized in that, in the invention described in claim 9, the following conditional expression is satisfied.
ν1f> 30 and ν1b> 30 (9)
However,
ν1f: Abbe number of the object side surface of the first lens ν1b: Abbe number of the image side surface of the first lens

Conditional expression (9) is a conditional expression that determines the Abbe number of the material of the first lens. When the value of conditional expression (9) exceeds the lower limit value, axial chromatic aberration can be kept small, and the image side surface of the first lens is a diverging surface, so that the peripheral portion of the screen is caused by a large amount of peripheral rays being bounced up. Chromatic aberration of magnification can be reduced. More preferably, the range of the following formula is good.
ν1f> 34 and ν1b> 34 (9) ′

An imaging lens according to an eleventh aspect is the lens according to the ninth or tenth aspect, wherein the first lens and the second lens are each provided with a substrate and a lens portion formed on the substrate. The following conditional expressions are satisfied.
n1f> 1.40 and n2f> 1.40 (10)
However,
n1f: Refractive index of the object side surface of the first lens n2f: Refractive index of the object side surface of the second lens

Conditional expression (10) is a conditional expression that determines the refractive indexes of the materials of the first lens and the second lens. When the value of conditional expression (10) exceeds the lower limit value, the Petzval sum does not become too large, so that it can be adjusted to the imaging surface of the curved solid-state imaging device. Further, since the curvature at the lens periphery is not too strong, the lateral chromatic aberration at the periphery of the screen can be reduced. More preferably, the range of the following formula is good.
n1f> 1.49 and n2f> 1.49 (10) ′

An imaging lens according to a twelfth aspect is characterized in that, in the invention according to any one of the first to eleventh aspects, the following conditional expression is satisfied.
−0.25 <f1 / f2 <1.40 (11)
However,
f1: Focal length of the first lens f2: Focal length of the second lens

Conditional expression (11) is a conditional expression that determines the focal length of the first lens and the second lens. When the value of conditional expression (11) is less than the upper limit value, the focal length of the second lens does not become too small compared to the focal length of the first lens, so the back focus does not become too long and the overall length can be shortened. On the other hand, when the value of the conditional expression (11) exceeds the lower limit value, the interval for inserting the cover glass or the IR cut filter of the solid-state image sensor is maintained. More preferably, the range of the following formula is good.
−0.10 <f1 / f2 <1.10 (11) ′

The imaging lens according to claim 13 is characterized in that, in the invention according to any one of claims 1 to 12, the solid-state imaging device is rotationally symmetric with respect to the optical axis. “Rotational symmetry with respect to the optical axis” means that the amount of curvature of the imaging surface that is equidistant from the center of the imaging surface is constant.

In recent years, the pixel pitch of a solid-state image sensor has become smaller, and a lens with a brighter F-number has been demanded. For this reason, if the lens is bent only in the long side direction like a film, the optical performance in the short side direction is deteriorated. Such deterioration of the optical performance can be avoided by making the amount of bending of the solid-state imaging device constant according to the distance in the optical axis orthogonal direction from the center of the solid-state imaging device.

An imaging lens according to a fourteenth aspect is characterized in that in the invention according to any one of the first to thirteenth aspects, the imaging lens further includes a lens having substantially no power. That is, even when a dummy lens having substantially no power is added to the configuration of claim 1, it is within the scope of application of the present invention.

An imaging apparatus according to a fifteenth aspect includes the imaging lens according to any one of the first to fourteenth aspects, and a solid-state imaging element whose imaging surface is curved in three dimensions.

The imaging apparatus of the present invention can acquire a high-quality image while using a two-lens imaging lens. The imaging device of the present invention can also be used for an imaging device mounted on or attached to a mobile phone, a portable information terminal, a flat-screen TV or a PC display, a drive recorder, a back monitor, or the like. In particular, the present invention is useful for devices that require an imaging lens or an imaging device with a short overall length, such as smartphones and tablet computers, which have a large display and are thin portable information devices.

According to the present invention, an imaging lens capable of obtaining a high image quality with a bright F-number, a short optical system overall length, and a high image quality while having a two-element configuration with respect to a solid-state imaging device having a curved imaging surface, and imaging using the imaging lens An apparatus can be provided.

It is a perspective view of the imaging device concerning this embodiment. It is the figure which showed typically the cross section along the optical axis of the imaging lens of the imaging device which concerns on this Embodiment. 1A and 1B are external views of a mobile phone that is an example of a mobile terminal provided with an imaging device according to the present embodiment, where FIG. 1A is a view seen from a side where an input unit is provided, and FIG. It is the figure seen from the side. 2 is a cross-sectional view of an imaging lens of Example 1. FIG. FIG. 4 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 1. 6 is a cross-sectional view of an imaging lens of Example 2. FIG. FIG. 6 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 2. 6 is a cross-sectional view of an imaging lens of Example 3. FIG. FIG. 6 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 3. 6 is a cross-sectional view of an imaging lens of Example 4. FIG. FIG. 6 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 4. 6 is a cross-sectional view of an imaging lens of Example 5. FIG. FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 5. 6 is a cross-sectional view of an imaging lens of Example 6. FIG. FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 6. 10 is a cross-sectional view of an imaging lens of Example 7. FIG. FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), and meridional coma aberration (d)) of the imaging lens of Example 7. 10 is a cross-sectional view of an imaging lens of Example 8. FIG. FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), and meridional coma aberration (d)) of the imaging lens of Example 8. 10 is a cross-sectional view of an imaging lens of Example 9. FIG. FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), and meridional coma aberration (d)) of the imaging lens of Example 9. 10 is a cross-sectional view of an imaging lens of Example 10. FIG. FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 10. 14 is a cross-sectional view of the imaging lens of Example 11. FIG. FIG. 14 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), and meridional coma aberration (d)) of the imaging lens of Example 11. 14 is a cross-sectional view of an imaging lens of Example 12. FIG. FIG. 14 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), and meridional coma aberration diagram (d)) of the imaging lens of Example 12. It is a figure which shows the displacement amount to the optical axis parallel direction from the surface vertex of a lens to the point in the height h of a lens surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a top view of an imaging apparatus 50 according to the present embodiment, and FIG. 2 is a cross-sectional view obtained by cutting the configuration of FIG. 1 along a cross section including an optical axis.

As illustrated in FIG. 1 or FIG. 2, the imaging device 50 includes a CMOS type imaging device 51 as a solid-state imaging device having a photoelectric conversion unit 51 a and an imaging lens that captures a subject image on the photoelectric conversion unit 51 a on the imaging device 51. 10 and a housing 20 made of a light shielding member having an opening for light incidence from the object side, and these are integrally formed.

As shown in FIG. 2, the image sensor 51 is curved in a spherical shape (preferably rotationally symmetric with respect to the optical axis) with a predetermined radius of curvature, and a pixel ( Photoelectric conversion elements) are two-dimensionally arranged, a photoelectric conversion unit 51a as a light receiving unit is formed, and a signal processing circuit 51b is formed around the photoelectric conversion unit 51a. The signal processing circuit 51b includes a driving circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal that forms an image signal output using the digital signal. It consists of a processing unit and the like. Note that the image pickup element is not limited to the above-described CMOS type image sensor, and may be one to which another one such as a CCD is applied.

The lower end of the housing 20 is fixed to the photoelectric conversion unit 51 a side of the image sensor 51 through the spacer B, and the side surface portion of the optical low-pass filter F that is a parallel plate is fixed to the inner periphery of the lower end of the housing 20. ing. The optical low-pass filter F is a flat plate here, but may be curved in accordance with the photoelectric conversion unit 51a.

A plurality of external electrodes 52 used for connection to an external circuit are formed on the other surface of the image sensor 51 (surface opposite to the photoelectric conversion unit 51a). The external electrode 52 and an external circuit (not shown) (for example, a control circuit included in a host device on which the imaging device is mounted) are connected to receive a voltage or a clock signal for driving the imaging device 51 from the external circuit. In addition, it is possible to output a digital YUV signal to an external circuit.

Although not shown, a substrate is disposed on the surface opposite to the photoelectric conversion unit 51a of the image sensor 51, the substrate and the image sensor 51 are connected by wire bonding, and an external surface is connected to the surface of the substrate opposite to the image sensor. A plurality of external electrodes used for connection with a circuit may be formed.

As shown in FIG. 2, the casing 20 made of a light shielding member holds the imaging lens 10 on the photoelectric conversion unit 51 a side of the imaging element 51.

The imaging lens 10 includes, in order from the object side, a meniscus first lens L1, a second lens L2, and an aperture stop S provided on the object side from the second lens L2 having a positive refractive power and convex toward the object side. The subject image is formed on the photoelectric conversion surface 51a of the image sensor 51.

Any one of the first lens L1, the second lens L2, and the optical low-pass filter F has an infrared light cut coat. Although not shown, an infrared light cut filter may be disposed in front of the optical low-pass filter instead of the infrared cut coat.

In FIG. 2, a disc-shaped light shielding member SH1 having an opening formed in the center is disposed between the flange portions L1c and L2c of the lenses L1 and L2 constituting the imaging lens 10, and the central opening serves as a diaphragm S. Constitute. The flange portions L1c and L2c of the lenses L1 and L2 are abutted with each other, and a spacer SP is provided between the flange portion L2c of the lens L2 and the optical low-pass filter F. A diaphragm S may be provided on the object side of the lens L1.

3A and 3B are external views of a mobile phone 100 that is an example of a mobile terminal provided with the imaging device 50 according to the present embodiment. In the mobile phone 100 shown in the figure, an upper casing 71 as a case having display screens D1 and D2 and a lower casing 72 having an operation button 60 as an input unit are connected via a hinge 73. Yes. The imaging device 50 is built below the display screen D <b> 2 in the upper casing 71, and is arranged so that the imaging device 50 can capture light from the outer surface side of the upper casing 71. Note that the position of the imaging device may be disposed above or on the side of the display screen D2 in the upper casing 71. Of course, the mobile phone is not limited to a folding type.

(Example)
Next, examples suitable for the above-described embodiment will be described. However, the present invention is not limited to the following examples. Symbols used in each example are as follows.
f: focal length of the entire imaging lens system fB: back focus Fno: F number 2Y: diagonal length ENTP along the imaging surface of the solid-state imaging device: entrance pupil position (distance from the first surface to the entrance pupil position)
EXTP: exit pupil position (distance from imaging surface to exit pupil position)
H1: Front principal point position (distance from first surface to front principal point position)
H2: Rear principal point position (distance from the final surface to the rear principal point position)
r: radius of curvature t: axial top surface spacing nd: refractive index νd of lens material with respect to d-line: Abbe number of lens material

In each embodiment, a surface in which “*” or [SPS] (an aspheric surface including an odd order) is described after each surface number is an aspheric surface, and the aspheric surface shape is It is expressed by the following “Equation 1” where the vertex is the origin, the X axis is taken in the optical axis direction, and the height in the direction perpendicular to the optical axis is h.

However,
Ai: i-order aspheric coefficient R: radius of curvature K: conic constant

Example 1
Lens data is shown in Table 1. In the following (including the lens data in the table), a power of 10 (for example, 2.5 × 10 ⁻⁰² ) is expressed using E (for example, 2.5e−002). 4 is a sectional view of the lens of Example 1. FIG. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. 5A is a spherical aberration diagram of Example 1, FIG. 5B is an astigmatism diagram, FIG. 5C is a distortion diagram, and FIG. 5D is a meridional coma aberration diagram. Here, in the spherical aberration diagram, the coma aberration diagram, and the meridional coma aberration diagram, g represents the amount of spherical aberration with respect to the g line, and d represents the amount of spherical aberration with respect to the d line. In the astigmatism diagram, the solid line S represents the sagittal plane, and the dotted line M represents the meridional plane (the same applies hereinafter). The first lens L1 and the second lens L2 are single lenses, and the aperture stop S is between the first lens L1 and the second lens L2. The first lens L1 is a glass lens, and the second lens L2 is a glass lens.

[table 1]
Example 1

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
1 * 0.8325 0.4528 1.75512 45.59 0.57
2 * 1.0496 0.0854 0.33
STO INFINITY 0.1089 0.28
4 * -20.0981 0.8354 1.75512 45.59 0.40
5 * -3.0092 0.3105 0.81
6 INFINITY 0.5500 1.51633 64.14
7 INFINITY 0.5000
IMG -8.0901 0.0000

ASPHERICAL SURFACE
1: K = 7.74111e-001, A4 = -1.13037e-001, A6 = 4.67147e-001, A8 = -1.14870e + 001,
A10 = 1.15302e + 002, A12 = -6.23049e + 002, A14 = 1.64718e + 003,
A16 = -1.73023e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
2: K = 2.19979e + 000, A4 = 1.99300e-002, A6 = 8.33235e + 000, A8 = -2.05035e + 002,
A10 = 2.21042e + 003, A12 = -4.98730e + 003, A14 = -2.72142e + 004,
A16 = 7.48554e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = -5.00000e + 001, A4 = -2.97004e-001, A6 = 6.75943e + 000, A8 = -1.09017e + 002,
A10 = 8.00678e + 002, A12 = -2.79629e + 003, A14 = -1.65536e + 002,
A16 = 3.55105e + 004, A18 = 1.04851e + 005, A20 = -1.18486e + 006
5: K = -1.40717e + 000, A4 = 5.34896e-0040, A6 = 2.51189e-001, A8 = -1.70186e + 0000,
A10 = 2.16871e + 000, A12 = 5.96340e + 000, A14 = -1.17631e + 001,
A16 = -2.80974e + 001, A18 = 8.42130e + 001, A20 = -5.64269e + 001

f = 2.15 mm
fB = 1.16 mm
Fno = 2.8
2Y = 2.84 mm
ENTP = 0.49 mm
EXTP = -1.36 mm
H1 = 0.13 mm
H2 = -1.66 mm

Single lens data

Lens Start surface Focal length (mm)
1 1 2.810
2 4 4.590

(Example 2)
Table 2 shows the lens data. 6 is a sectional view of the lens of Example 2. FIG. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. 7A is a spherical aberration diagram of Example 2, FIG. 7B is an astigmatism diagram, FIG. 7C is a distortion diagram, and FIG. 7D is a meridional coma aberration diagram. The first lens L1 and the second lens L2 are single lenses, and the aperture stop S is between the first lens L1 and the second lens L2. The first lens L1 is a glass lens, and the second lens L2 is a glass lens.

[Table 2]
Example 2

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
1 * 0.8425 0.4293 1.75512 45.59 0.55
2 * 1.0549 0.0805 0.33
STO INFINITY 0.1039 0.29
4 * -111.8889 0.8150 1.75512 45.59 0.39
5 * -3.4420 0.3907 0.74
6 INFINITY 0.5500 1.51633 64.14
7 INFINITY 0.5000
IMG -6.2685 0.0000

ASPHERICAL SURFACE
1: K = 7.76603e-001, A4 = -1.12376e-001, A6 = 4.77421e-001, A8 = -1.14984e + 001,
A10 = 1.15241e + 002, A12 = -6.23151e + 002, A14 = 1.64734e + 003,
A16 = -1.72924e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
2: K = 2.05589e + 000, A4 = 8.12280e-004, A6 = 8.11398e + 000, A8 = -2.06773e + 002,
A10 = 2.18520e + 003, A12 = -4.98730e + 003, A14 = -2.72142e + 004,
A16 = 7.48554e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 5.00000e + 001, A4 = -3.06866e-001, A6 = 6.84365e + 000, A8 = -1.08989e + 002,
A10 = 7.97792e + 002, A12 = -2.81339e + 003, A14 = -2.01321e + 002,
A16 = 3.57375e + 004, A18 = 1.07130e + 0050, A20 = -1.19090e + 006
5: K = -2.13723e + 000, A4 = 2.30927e-004, A6 = 2.58270e-001, A8 = -1.70087e + 000,
A10 = 2.16246e + 000, A12 = 5.95162e + 000, A14 = -1.17753e + 00, A16 = -2.81014e + 001,
A18 = 8.42259e + 001, A20 = -5.63948e + 001

f = 2.19 mm
fB = 1.25 mm
Fno = 2.8
2Y = 2.84 mm
ENTP = 0.45 mm
EXTP = -1.40 mm
H1 = 0.09 mm
H2 = -1.71 mm

Single lens data

Lens Start surface Focal length (mm)
1 1 2.960
2 4 4.690

(Example 3)
Table 3 shows lens data. FIG. 8 is a sectional view of the lens of Example 3. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. FIG. 9A is a spherical aberration diagram of Example 3, FIG. 9B is an astigmatism diagram, FIG. 9C is a distortion diagram, and FIG. 9D is a meridional coma aberration diagram. The first lens L1 and the second lens L2 are single lenses, and the aperture stop S is between the first lens L1 and the second lens L2. The first lens L1 is a glass lens, and the second lens L2 is a glass lens.

[Table 3]
Example 3

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
1 * 0.8223 0.5455 1.57207 34.88 0.59
2 * 1.0550 0.0603 0.30
STO INFINITY 0.0794 0.29
4 * 68.9380 0.6682 1.71539 43.29 0.38
5 * -2.5652 0.4598 0.67
6 INFINITY 0.5500 1.51633 64.14
7 INFINITY 0.5000
IMG -9.9213 0.0000

ASPHERICAL SURFACE
1: K = 7.37941e-001, A4 = -1.57593e-001, A6 = 3.49155e-001, A8 = -1.17225e + 001,
A10 = 1.14791e + 002, A12 = -6.24317e + 002, A14 = 1.64366e + 003,
A16 = -1.73959e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
2: K = 2.17700e + 000, A4 = 1.84993e-002, A6 = 8.27100e + 000, A8 = -2.07531e + 002,
A10 = 2.18630e + 003, A12 = -4.98730e + 003, A14 = -2.72142e + 004,
A16 = 7.48554e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = -4.48684e + 001, A4 = -2.82950e-001, A6 = 6.84504e + 000, A8 = -1.06646e + 002,
A10 = 8.14816e + 002, A12 = -2.77302e + 003, A14 = -5.12683e + 002,
A16 = 3.18101e + 004, A18 = 9.07088e + 004, A20 = -1.05427e + 006
5: K = 7.60680e-001, A4 = -1.59596e-002, A6 = 2.08662e-001, A8 = -1.73543e + 000,
A10 = 2.15606e + 000, A12 = 5.97318e + 000, A14 = -1.17416e + 001,
A16 = -2.80854e + 001, A18 = 8.42082e + 001, A20 = -5.63702e + 001

f = 2.17 mm
fB = 1.32 mm
Fno = 2.8
2Y = 2.84 mm
ENTP = 0.56 mm
EXTP = -1.36 mm
H1 = 0.19 mm
H2 = -1.68 mm

Single lens data

Lens Start surface Focal length (mm)
1 1 3.517
2 4 3.471

Example 4
Table 4 shows the lens data. FIG. 10 is a sectional view of the lens of Example 4. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. 11A is a spherical aberration diagram of Example 4, FIG. 11B is an astigmatism diagram, FIG. 11C is a distortion aberration diagram, and FIG. 11D is a meridional coma aberration diagram. The first lens L1 and the second lens L2 are single lenses, and the aperture stop S is on the object side of the first lens L1. The first lens L1 is a glass lens, and the second lens L2 is a glass lens.

[Table 4]
Example 4

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
STO INFINITY 0.0500 0.42
2 INFINITY -0.0703 0.45
3 * 0.8936 0.7243 1.58376 56.27 0.51
4 * 1.6461 0.4119 0.51
5 * 6.3882 0.9000 1.58376 56.27 0.68
6 * 4.6980 0.0534 1.14
7 INFINITY 0.6220 1.51633 64.14
8 INFINITY 0.2000
IMG -16.5190 0.0000

ASPHERICAL SURFACE
3: K = -2.51009e-001, A4 = 3.77875e-002, A6 = 3.21731e-001, A8 = -8.20229e-001,
A10 = 1.10419e + 000, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 5.47356e + 000, A4 = 4.45048e-003, A6 = 1.15005e + 000, A8 = -3.34570e + 000,
A10 = 9.64316e + 000, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = -6.96231e + 000, A4 = -3.74955e-001, A6 = 4.53090e-001, A8 = -2.31109e + 000,
A10 = 6.96332e + 000, A12 = -1.48006e + 001, A14 = 1.32818e + 001, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
6: K = -1.12035e + 001, A4 = -1.00631e-001, A6 = 2.21635e-002, A8 = -4.37315e-002,
A10 = 7.05668e-003, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 2.39 mm
fB = 0.66 mm
Fno = 2.8
2Y = 2.87 mm
ENTP = 0.00 mm
EXTP = -1.67 mm
H1 = -0.66 mm
H2 = -2.19 mm

Single lens data

Lens Start surface Focal length (mm)
1 3 2.472
2 5 -37.844

(Example 5)
Table 5 shows the lens data. 12 is a sectional view of the lens of Example 5. FIG. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. 13A is a spherical aberration diagram of Example 5, FIG. 13B is an astigmatism diagram, FIG. 13C is a distortion diagram, and FIG. 13D is a meridional coma aberration diagram. The first lens L1 and the second lens L2 are single lenses, and the aperture stop S is on the object side of the first lens L1. The first lens L1 is a glass lens, and the second lens L2 is a resin lens.

[Table 5]
Example 5

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
STO INFINITY 0.0500 0.43
2 INFINITY -0.0755 0.46
3 * 0.8758 0.6727 1.56758 56.29 0.51
4 * 1.5975 0.4036 0.51
5 * 6.1433 0.8760 1.51751 56.34 0.68
6 * 6.6593 0.1374 1.10
7 INFINITY 0.6220 1.51633 64.14
8 INFINITY 0.2000
IMG -10.4901 0.0000

ASPHERICAL SURFACE
3: K = -2.24372e-001, A4 = 4.73513e-002, A6 = 2.93037e-001, A8 = -5.61696e-001,
A10 = 6.98038e-001, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 5.35554e + 000, A4 = 1.65123e-002, A6 = 1.16449e + 000, A8 = -3.27017e + 000,
A10 = 9.83740e + 000, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = 1.73115e + 001, A4 = -3.66290e-001, A6 = 4.46528e-001, A8 = -2.43667e + 000,
A10 = 7.21927e + 000, A12 = -1.39787e + 001, A14 = 1.24475e + 001, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
6: K = 2.67581e + 001, A4 = -1.06058e-001, A6 = 9.96793e-003, A8 = -3.59262e-002,
A10 = 3.09509e-003, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 2.41 mm
fB = 0.75 mm
Fno = 2.8
2Y = 2.87 mm
ENTP = 0.00 mm
EXTP = -1.80 mm
H1 = -0.49 mm
H2 = -2.21 mm

Single lens data

Lens Start surface Focal length (mm)
1 3 2.554
2 5 97.032

(Example 6)
Table 6 shows the lens data. FIG. 14 is a sectional view of the lens of Example 6. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. FIG. 15A is a spherical aberration diagram of Example 6, FIG. 15B is an astigmatism diagram, FIG. 15C is a distortion diagram, and FIG. 15D is a meridional coma aberration diagram. The first lens L1 and the second lens L2 are single lenses, and the aperture stop S is on the object side of the first lens L1. The first lens L1 is a resin lens, and the second lens L2 is a glass lens.

[Table 6]
Example 6

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
STO INFINITY 0.0500 0.41
2 INFINITY -0.0668 0.44
3 * 0.8502 0.7235 1.49473 64.23 0.50
4 * 2.0624 0.3916 0.53
5 * 6.3072 0.7989 1.73920 59.55 0.69
6 * 6.1474 0.1757 1.08
7 INFINITY 0.6220 1.51633 64.14
8 INFINITY 0.2000
IMG -9.3955 0.0000

ASPHERICAL SURFACE
3: K = -2.61216e-001, A4 = 3.38293e-002, A6 = 2.90645e-001, A8 = -4.47149e-001,
A10 = 1.25687e-001, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 5.75728e + 000, A4 = 2.07335e-002, A6 = 1.31375e + 000, A8 = -3.19799e + 000,
A10 = 1.04609e + 001, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = 2.92688e + 001, A4 = -3.50327e-001, A6 = 4.47162e-001, A8 = -2.50094e + 000,
A10 = 7.25365e + 000, A12 = -1.38200e + 001, A14 = 1.15734e + 001, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
6: K = 2.39573e + 001, A4 = -1.09131e-001, A6 = -1.08533e-002, A8 = -2.06293e-002,
A10 = 1.53061e-003, A12 = 0.00000e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 2.30 mm
fB = 0.79 mm
Fno = 2.8
2Y = 2.87 mm
ENTP = 0.00 mm
EXTP = -1.70 mm
H1 = -0.42 mm
H2 = -2.05 mm

Single lens data

Lens Start surface Focal length (mm)
1 3 2.442
2 5 291.774

(Example 7)
Table 7 shows the lens data. FIG. 16 is a sectional view of the lens of Example 7. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. FIG. 17A is a spherical aberration diagram of Example 7, FIG. 17B is an astigmatism diagram, FIG. 17C is a distortion diagram, and FIG. 17D is a meridional coma aberration diagram. The first lens L1 is a multilayer lens composed of a parallel plate substrate LS1, a lens portion L1a formed on the object side, and a lens portion L1b formed on the image side of the substrate LS1, and the second lens L2 The lens LS2 has a multilayer structure including a parallel plate substrate LS2, a lens portion L2a formed on the object side thereof, and a lens portion L12 formed on the image side of the substrate LS2. The aperture stop S is a parallel plate substrate LS1. And the lens portion L1a formed on the object side. The first lens L1 and the second lens L2 are formed by transferring a resin material or the like onto a transparent parallel plate made of glass or resin, for example, using a curable resin material and curing the resin material. This is a lens obtained by cutting a so-called wafer level lens formed by arranging the lens portions into individual pieces. Even such a multilayer lens is made of a single material such as resin or glass from the viewpoint of an imaging lens for forming a subject image on the imaging surface of a solid-state imaging device curved in three dimensions. It is possible to further reduce the manufacturing cost while obtaining the same optical performance as the lens has. Further, by using such a lens, the material constituting the object side surface and the image side surface of each lens unit can be changed, so that the chromatic aberration and the image surface can be improved. In addition, since the wafer level lens can mold a large number of lenses at a time, the cost can be reduced.

[Table 7]
Example 7

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 1000.0000
1SPS 0.8654 0.3338 1.51665 56.27 0.54
STO INFINITY 0.3000 1.51690 61.89 0.43
3 INFINITY 0.0800 1.57208 34.88 0.47
4SPS 2.3025 0.3664 0.49
5 * -6.3995 0.0575 1.51615 55.05 0.62
6 INFINITY 0.9632 1.51690 61.89 0.72
7 INFINITY 0.4400 1.55296 39.50 1.3
8 * -151.6641 0.1619 1.4
9 INFINITY 0.3500 1.47140 65.19
10 INFINITY 0.2000
IMG -13.9634 0.0000

ASPHERICAL SURFACE
1: K = 6.37674e-001, A3 = -1.06002e-001, A4 = 1.65387e-001, A5 = 0.00000e + 000,
A6 = 1.53651e-001, A7 = 0.00000e + 000, A8 = -1.47903e + 001, A9 = 0.00000e + 000,
A10 = 9.40919e + 001, A11 = 0.00000e + 000, A12 = -2.63513e + 002, A13 = 0.00000e + 000,
A14 = 2.67490e + 002, A15 = 0.00000e + 000, A16 = 0.00000e + 000, A17 = 0.00000e + 000,
A18 = 0.00000e + 000, A19 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 1.56132e + 001, A3 = -6.35449e-002, A4 = 2.96711e-001, A5 = 0.00000e + 000,
A6 = -2.77475e + 000, A7 = 0.00000e + 000, A8 = 2.38186e + 001, A9 = 0.00000e + 000,
A10 = -1.01043e + 002, A11 = 0.00000e + 000, A12 = 1.94244e + 002, A13 = 0.00000e + 000,
A14 = -1.24473e + 002, A15 = 0.00000e + 000, A16 = 0.00000e + 000, A17 = 0.00000e + 000,
A18 = 0.00000e + 000, A19 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = -4.24641e + 001, A4 = -3.41997e-001, A6 = 4.50290e + 000, A8 = -1.26646e + 002,
A10 = 1.44719e + 003, A12 = -8.99411e + 003, A14 = 3.26300e + 004,
A16 = -6.87009e + 004, A18 = 7.69040e + 004, A20 = -3.47942e + 004
8: K = 4.99667e + 001, A4 = -2.66052e-003, A6 = -7.42506e-002, A8 = 5.51350e-002,
A10 = -2.59968e-002, A12 = 4.85271e-003, A14 = 3.87280e-004,
A16 = -2.36131e-004, A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 2.68 mm
fB = 0.60 mm
Fno = 2.8
2Y = 3.54 mm
ENTP = 0.25 mm
EXTP = -1.94 mm
H1 = -0.48 mm
H2 = -2.51 mm

Single lens data

Lens Start surface Focal length (mm)
1 1 2.392
2 5 -13.033

(Example 8)
Table 8 shows the lens data. FIG. 18 is a sectional view of the lens of Example 8. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. 19A is a spherical aberration diagram of Example 8, FIG. 19B is an astigmatism diagram, FIG. 19C is a distortion diagram, and FIG. 19D is a meridional coma aberration diagram. The first lens L1 is a compound lens composed of a parallel plate substrate LS1, a lens portion L1a formed on the object side thereof, and a lens portion L1b formed on the image side of the substrate LS1. This is a lens obtained by dividing the level lens into individual pieces. The second lens L2 is a single glass lens, and the aperture stop S is formed between a parallel plate substrate LS1 and a lens portion L1a formed on the object side thereof.

[Table 8]
Example 8

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 1000.0000
1SPS 0.8655 0.3549 1.51665 56.27 0.55
STO INFINITY 0.3000 1.51690 61.89 0.43
3 INFINITY 0.0851 1.57208 34.88 0.47
4SPS 2.3265 0.3580 0.49
5 * -6.0376 1.3800 1.59628 36.26 0.61
6 * -49.7739 0.2492 1.37
7 INFINITY 0.3500 1.47140 65.19
8 INFINITY 0.2000
IMG -14.6765 0.0000

ASPHERICAL SURFACE
1: K = 6.27071e-001, A3 = -1.05382e-001, A4 = 1.62139e-001, A5 = 0.00000e + 000,
A6 = 1.23709e-001, A7 = 0.00000e + 000, A8 = -1.47495e + 001, A9 = 0.00000e + 000,
A10 = 9.43630e + 001, A11 = 0.00000e + 000, A12 = -2.63276e + 002, A13 = 0.00000e + 000,
A14 = 2.64398e + 002, A15 = 0.00000e + 000, A16 = 0.00000e + 000, A17 = 0.00000e + 000,
A18 = 0.00000e + 000, A19 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 1.56741e + 001, A3 = -6.70734e-002, A4 = 2.93198e-001, A5 = 0.00000e + 000,
A6 = -2.75460e + 000, A7 = 0.00000e + 000, A8 = 2.38459e + 001, A9 = 0.00000e + 000,
A10 = -1.01612e + 002, A11 = 0.00000e + 000, A12 = 1.93062e + 002, A13 = 0.00000e + 000,
A14 = -1.09145e + 002, A15 = 0.00000e + 000, A16 = 0.00000e + 000, A17 = 0.00000e + 000,
A18 = 0.00000e + 000, A19 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = -5.00000e + 001, A4 = -3.23880e-001, A6 = 4.50722e + 000, A8 = -1.26665e + 002,
A10 = 1.44721e + 003, A12 = -8.99415e + 003, A14 = 3.26301e + 004,
A16 = -6.87001e + 004, A18 = 7.69079e + 004, A20 = -3.47784e + 004
6: K = 6.91292e + 000, A4 = -7.34637e-003, A6 = -7.34338e-002, A8 = 5.51963e-002,
A10 = -2.60199e-002, A12 = 4.83938e-003, A14 = 3.82653e-004,
A16 = -2.37405e-004, A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 2.70 mm
fB = 0.69 mm
Fno = 2.8
2Y = 3.54 mm
ENTP = 0.27 mm
EXTP = -1.94 mm
H1 = -0.50 mm
H2 = -2.53 mm

Single lens data

Lens Start surface Focal length (mm)
1 1 2.368
2 5 -11.661

Example 9
Table 9 shows the lens data. FIG. 20 is a sectional view of the lens of Example 9. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, etc. I is an imaging surface. Show. 21A is a spherical aberration diagram of Example 9, FIG. 21B is an astigmatism diagram, FIG. 21C is a distortion diagram, and FIG. 21D is a meridional coma aberration diagram. The first lens L1 is a single glass lens, and the second lens L2 includes a parallel plate substrate LS2, a lens portion L2a formed on the object side, and a lens portion L2b formed on the image side of the substrate LS2. This is a compound lens, which is a lens obtained by dividing a wafer level lens into pieces as in the seventh embodiment. The aperture stop S is formed between the first lens L1 and the second lens L2.

[Table 9]
Example 9

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 400.0000
1 * 0.8350 0.4675 1.75512 45.59 0.58
2 * 1.0291 0.0860 0.33
STO INFINITY 0.0839 0.28
4 * -98.6942 0.2468 1.57207 34.88 0.37
5 INFINITY 0.4088 1.63923 38.83 0.52
6 INFINITY 0.1991 1.67930 47.29 0.75
7 * -2.8174 0.2566 0.8
8 INFINITY 0.5500 1.51633 64.14
9 INFINITY 0.5000
IMG -9.9960 0.0000

ASPHERICAL SURFACE
1: K = 7.72606e-001, A4 = -1.14493e-001, A6 = 4.49784e-001, A8 = -1.15537e + 001,
A10 = 1.15225e + 002, A12 = -6.22995e + 002, A14 = 1.64730e + 003,
A16 = -1.73139e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
2: K = 2.18653e + 000, A4 = 1.99096e-002, A6 = 8.21545e + 000, A8 = -2.07373e + 002,
A10 = 2.22488e + 003, A12 = -4.98730e + 003, A14 = -2.72142e + 004,
A16 = 7.48554e + 003, A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 5.00000e + 001, A4 = -3.08700e-001, A6 = 6.39047e + 000, A8 = -1.08707e + 002,
A10 = 8.10304e + 002, A12 = -2.75193e + 003, A14 = -1.42721e + 002,
A16 = 3.46124e + 004, A18 = 1.00282e + 005, A20 = -1.17397e + 006
7: K = -2.07569e + 000, A4 = 4.19194e-003, A6 = 2.40795e-001, A8 = -1.70631e + 000,
A10 = 2.16973e + 000, A12 = 5.96850e + 000, A14 = -1.17584e + 001,
A16 = -2.80976e + 001, A18 = 8.42178e + 001, A20 = -5.63612e + 001

f = 2.13 mm
fB = 1.19 mm
Fno = 2.8
2Y = 2.96 mm
ENTP = 0.51 mm
EXTP = -1.40 mm
H1 = 0.14 mm
H2 = -1.71 mm

Single lens data

Lens Start surface Focal length (mm)
1 1 2.879
2 4 4.236

(Example 10)
Table 10 shows the lens data. FIG. 22 is a sectional view of the lens of Example 10. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, and I is an imaging surface. FIG. 23 (a) is a spherical aberration diagram of Example 10, FIG. 23 (b) is an astigmatism diagram, FIG. 23 (c) is a distortion diagram, and FIG. 23 (d) is a meridional coma aberration diagram. The first lens L1 is a single lens, the second lens L2 is a single lens, and the aperture stop S is formed on the object side of the first lens L1. The first lens L1 is a resin lens, and the second lens L2 is a resin lens.

[Table 10]
Example 10

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 1e + 010
STO INFINITY 0.0500 0.52
2 INFINITY -0.1294 0.53
3 * 1.0556 0.5254 1.54470 56.19 0.55
4 * 1.7302 0.5523 0.59
5 * -54.0201 0.5730 1.54470 56.19 0.90
6 * -3.5854 1.7450 1.23
IMG -7.9000 0.0000

ASPHERICAL SURFACE
3: K = -2.55721e-002, A4 = 1.85271e-002, A6 = 2.21956e-001, A8 = -7.24440e-001,
A10 = 2.22994e + 000, A12 = -2.72820e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 3.69038e + 000, A4 = 9.23765e-002, A6 = 6.44387e-002, A8 = -2.65755e-001,
A10 = 1.70831e + 000, A12 = -8.08348e-001, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = -1.02970e + 002, A4 = 2.28296e-002, A6 = -1.51874e-001, A8 = 8.29048e-002,
A10 = -1.09607e-001, A12 = 4.58055e-002, A14 = -6.96157e-002,
A16 = 0.00000e + 000, A18 = 0.00000e + 000, A20 = 0.00000e + 000
6: K = -5.00000e + 001, A4 = -3.11841e-002, A6 = 3.93524e-002, A8 = -2.64489e-002,
A10 = -4.11103e-002, A12 = 3.96287e-002, A14 = -1.18093e-002,
A16 = 0.00000e + 000, A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 2.95 mm
fB = 1.75 mm
Fno = 2.8
2Y = 4.53 mm
ENTP = 0.00 mm
EXTP = -3.15 mm
H1 = 0.19 mm
H2 = -2.95 mm

Single lens data

Lens Start surface Focal length (mm)
1 3 3.900
2 5 7.022

(Example 11)
Table 11 shows the lens data. FIG. 24 is a sectional view of the lens of Example 11. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, and I is an imaging surface. FIG. 25A is a spherical aberration diagram of Example 11, FIG. 25B is an astigmatism diagram, FIG. 25C is a distortion diagram, and FIG. 25D is a meridional coma aberration diagram. The first lens L1 is a single lens, the second lens L2 is a single lens, and the aperture stop S is formed on the object side of the first lens L1. The first lens L1 is a resin lens, and the second lens L2 is a resin lens.

[Table 11]
Example 11

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 1e + 010
STO INFINITY 0.0500 0.53
2 INFINITY -0.1083 0.54
3 * 1.2179 0.6467 1.54470 56.19 0.56
4 * 2.1074 0.6012 0.65
5 * -801.6790 0.6144 1.54470 56.19 1.03
6 * -3.2478 1.7330 1.33
IMG -6.8931 0.0000

ASPHERICAL SURFACE
3: K = -8.35886e-002, A4 = 6.33414e-003, A6 = 1.78765e-001, A8 = -6.20559e-001,
A10 = 1.61548e + 000, A12 = -1.88543e + 000, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = 4.38529e + 000, A4 = 7.25749e-002, A6 = -6.52342e-003, A8 = -1.06614e-001,
A10 = 8.07426e-001, A12 = -7.39941e-001, A14 = 0.00000e + 000, A16 = 0.00000e + 000,
A18 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = -9.44828e + 004, A4 = 3.08602e-002, A6 = -1.06667e-001, A8 = 1.49256e-001,
A10 = -2.36159e-001, A12 = 1.84400e-001, A14 = -6.69319e-002,
A16 = 0.00000e + 000, A18 = 0.00000e + 000, A20 = 0.00000e + 000
6: K = -3.46914e + 001, A4 = -4.40803e-002, A6 = 5.52254e-002, A8 = -2.24381e-002,
A10 = -2.51649e-002, A12 = 2.10058e-002, A14 = -5.17048e-003,
A16 = 0.00000e + 000, A18 = 0.00000e + 000, A20 = 0.00000e + 000

f = 3.00 mm
fB = 1.77 mm
Fno = 2.8
2Y = 4.53 mm
ENTP = 0.00 mm
EXTP = -3.44 mm
H1 = 0.38 mm
H2 = -3.00 mm

Single lens data

Lens Start surface Focal length (mm)
1 3 4.216
2 5 5.985

(Example 12)
Lens data is shown in Table 12. FIG. 26 is a sectional view of the lens of Example 12. In the figure, L1 is a first lens, L2 is a second lens, S is an aperture stop, and I is an imaging surface. 27A is a spherical aberration diagram of Example 12, FIG. 27B is an astigmatism diagram, FIG. 27C is a distortion diagram, and FIG. 27D is a meridional coma aberration diagram. The first lens L1 is a single lens, the second lens L2 is a single lens, and the aperture stop S is formed on the object side of the first lens L1. The first lens L1 is a glass lens, and the second lens L2 is a glass lens.

[Table 12]
Example 12

SURF DATA
NUM.r d nd vd Effective radius (mm)
OBJ INFINITY 1000.0000
STO INFINITY 0.0500 0.42
2 INFINITY -0.0927 0.42
3SPS 0.8823 0.4895 1.58313 59.44 0.44
4SPS 1.5817 0.4908 0.48
5 * -44.9353 1.0676 1.58313 59.44 0.75
6 * -3.3784 0.9560 1.29
IMG -7.7317 0.0000

ASPHERICAL SURFACE
3: K = -3.18388e + 000, A3 = -1.08727e-001, A4 = 1.05335e + 000, A5 = 0.00000e + 000,
A6 = -2.23388e + 000, A7 = 0.00000e + 000, A8 = 3.29672e + 000, A9 = 0.00000e + 000,
A10 = 5.01550e + 001, A11 = 0.00000e + 000, A12 = -3.23782e + 002, A13 = 0.00000e + 000,
A14 = 7.94440e + 002, A15 = 0.00000e + 000, A16 = -7.89940e + 002, A17 = 0.00000e + 000,
A18 = 0.00000e + 000, A19 = 0.00000e + 000, A20 = 0.00000e + 000
4: K = -1.05882e + 001, A3 = 5.21279e-002, A4 = 4.92990e-001, A5 = 0.00000e + 000,
A6 = 4.06877e-001, A7 = 0.00000e + 000, A8 = 2.99123e + 000, A9 = 0.00000e + 000,
A10 = -7.51279e + 000, A11 = 0.00000e + 000, A12 = -1.10928e + 002,
A13 = 0.00000e + 000, A14 = 9.20783e + 002, A15 = 0.00000e + 000, A16 = -1.71585e + 003,
A17 = 0.00000e + 000, A18 = 0.00000e + 000, A19 = 0.00000e + 000, A20 = 0.00000e + 000
5: K = -4.76637e + 003, A4 = -1.41107e-001, A6 = 4.21319e-001, A8 = -3.29976e + 000,
A10 = 9.80144e + 000, A12 = -1.60152e + 001, A14 = 1.62835e + 001,
A16 = -1.62053e + 001, A18 = 1.12444e + 001, A20 = 8.13832e-001
6: K = 0.00000e + 000, A4 = 6.40584e-002, A6 = -8.70658e-002, A8 = 6.62701e-002,
A10 = -3.61565e-002, A12 = 1.01357e-003, A14 = 5.83060e-003,
A16 = -2.39215e-004, A18 = -1.33294e-003, A20 = 3.79676e-004

f = 2.35 mm
fB = 0.96 mm
Fno = 2.8
2Y = 3.58 mm
ENTP = 0.00 mm
EXTP = -1.85 mm
H1 = 0.32 mm
H2 = -1.48 mm

Single lens data

Lens Start surface Focal length (mm)
1 3 2.720
2 5 6.206

Table 13 summarizes the values of the conditional expressions described in the claims.

As the paraxial radius of curvature, a sag amount s measured using a contact type method or a non-contact type method with an ultra-high precision coordinate measuring machine (UA3P) or the like is given by the following formula. An approximate value r ′ of the axial curvature radius may be used.
r ′ = {(h) ² + (s) ² } / (2s)
However,
h: Height of 1/10 of the effective radius on the lens surface s: Displacement in the direction parallel to the optical axis from the surface apex to the point at the height h of the lens surface (see FIG. 28)

Here, the effective radius of the lens surface means that the light beam passing through the outermost side (position farthest from the optical axis of the lens) among all the light rays that are formed at the maximum image height intersects the lens surface. Means the height in the direction perpendicular to the optical axis.

The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are apparent to those skilled in the art from the embodiments and ideas described in the present specification. It is. For example, even when a dummy lens having substantially no power is further provided, it is within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Imaging lens 20 Case 50 Imaging device 51a Photoelectric conversion part 51b Signal processing circuit 52 External electrode 60 Operation button 71 Upper case 72 Lower case 73 Hinge 100 Cellular phone B, SP Spacer F Optical low-pass filter D1, D2 Display screen L1 First lens L2 Second lens S Aperture stop SH1 Light blocking member

Claims (15)

1. An imaging lens for forming a subject image on an imaging surface of a solid-state imaging device that is curved three-dimensionally with an optical axis as a center, and is provided on the object side and has a positive refractive power and is convex on the object side A first lens of meniscus, a second lens provided on the image side and having a positive or negative refractive power, and an aperture stop provided on the object side of the second lens, and satisfying the following conditional expression An imaging lens characterized by.
   0.40 <r2 / f <4.0 (1)
   However,
   r2: radius of curvature of the image side surface of the first lens f: focal length of the entire system
2. The imaging lens according to claim 1, wherein the following conditional expression is satisfied.
   0.15 <PTZ <0.40 (2)
   However,
   PTZ: Petzval sum of the first lens and the second lens
3. The imaging lens according to claim 1, wherein the following conditional expression is satisfied.
   0.30 <d3 / f <2.60 (3)
   However,
   d3: Core thickness of the second lens
4. The imaging lens according to any one of claims 1 to 3, wherein the following conditional expression is satisfied.
   0.30 <r1 / f <2.30 (4)
   However,
   r1: radius of curvature of the object side surface of the first lens
5. The imaging lens according to any one of claims 1 to 4, wherein the following conditional expression is satisfied.
   0.10 <fB / TL <0.60 (5)
   However,
   fB: Distance between the image side surface of the second lens and the solid-state imaging device TL: Total lens length
6. The imaging lens according to any one of claims 1 to 5, wherein the following conditional expression is satisfied.
   −0.38 <Y / rI <−0.01 (6)
   However,
   rI: radius of curvature of the imaging surface Y: maximum image height
7. The imaging lens according to any one of claims 1 to 6, wherein the following conditional expression is satisfied.
   ν1> 30 (7)
   However,
   ν1: Abbe number of the first lens
8. The imaging lens according to any one of claims 1 to 7, wherein the following conditional expression is satisfied.
   n1> 1.40 and n2> 1.40 (8)
   However,
   n1: Refractive index of the first lens n2: Refractive index of the second lens
9. The lens according to any one of claims 1 to 6, wherein at least one of the first lens and the second lens is a lens including a substrate and a lens portion formed on the substrate. Imaging lens.
10. The imaging lens according to claim 9, wherein the first lens satisfies the following conditional expression.
    ν1f> 30 and ν1b> 30 (9)
    However,
    ν1f: Abbe number of the object side surface of the first lens ν1b: Abbe number of the image side surface of the first lens
11. 11. The lens according to claim 9, wherein each of the first lens and the second lens includes a substrate and a lens portion formed on the substrate, and satisfies the following conditional expression. Imaging lens.
    n1f> 1.40 and n2f> 1.40 (10)
    However,
    n1f: Refractive index of the object side surface of the first lens n2f: Refractive index of the object side surface of the second lens
12. The imaging lens according to any one of claims 1 to 11, wherein the following conditional expression is satisfied.
    −0.25 <f1 / f2 <1.40 (11)
    However,
    f1: Focal length of the first lens f2: Focal length of the second lens
13. The imaging lens according to any one of claims 1 to 12, wherein an imaging surface of the solid-state imaging device is rotationally symmetric with respect to an optical axis.
14. The imaging lens according to any one of claims 1 to 13, further comprising a lens having substantially no power.
15. 15. An imaging apparatus comprising: the imaging lens according to claim 1; and a solid-state imaging device whose imaging surface is curved in three dimensions.

Images