JP2010256608A - Imaging lens, imaging optical device and digital apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging lens composed of five lenses, which satisfactorily corrects a spherical aberration and an astigmatic aberration even when the entire lens length is shortened in accordance with the compact size of a lens unit, and which suppresses image quality degradation resulting from an eccentricity error, and to provide an imaging optical device and a digital apparatus. <P>SOLUTION: The imaging lens LN includes, in order from an object side, a first lens L1 of positive refractive power, the convex face of which is oriented on the object side, a second lens L2, the concave face of which is oriented in the direction of the object side, a third lens L3 of positive refractive power, the fourth lens L4 of positive or negative refractive power, and a fifth lens L5 of positive or negative refractive power. Each of the first and third lenses L1 and L3 has at least one aspherical face, and satisfies the following conditional expression: 0.4&lt;f3/f1&lt;1.9 (f1 is the focal distance of the first lens L1, and f3 is the focal distance of the third lens L3). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an imaging lens, an imaging optical device, and a digital device. More specifically, an imaging optical device that captures an image of a subject with an image sensor (for example, a solid-state image sensor such as a charge coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor) and the like are mounted. The present invention relates to a digital apparatus with an image input function and a small imaging lens that forms an optical image of a subject on a light receiving surface of an imaging element.

  2. Description of the Related Art In recent years, digital devices with an image input function such as a mobile phone and a portable information terminal equipped with an imaging optical device are becoming widespread with the improvement in performance and size of imaging devices. Further, there is an increasing demand for further downsizing and higher performance of the imaging lens mounted on the imaging optical device. As an imaging lens for such an application, an imaging lens having a five-lens configuration has been conventionally proposed. A five-lens imaging lens can have higher performance than a three-lens or four-lens imaging lens.

  As an imaging lens having the above five-lens configuration, for example, in Patent Document 1, in order from the object side, a first lens having a positive refractive power, a second lens having a negative refractive power, and a positive refractive power are provided. An imaging lens including a third lens, a fourth lens having negative refractive power, and a fifth lens having negative refractive power is disclosed. Patent Document 2 also describes, in order from the object side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a negative refractive power. An imaging lens configured by a fourth lens having a fifth lens having a negative refractive power is disclosed.

JP 2007-264180 A JP 61-87119 A

  However, the imaging lens described in Patent Document 1 has insufficient correction of spherical aberration and astigmatism, and cannot fully utilize the merit of using five lenses. Furthermore, when the total lens length is shortened, there is a problem that it becomes difficult to cope with the increase in the number of pixels of the image pickup device due to the deterioration of the optical performance. Moreover, since the imaging lens described in Patent Document 2 has a zooming function, it is not sufficiently compact.

  The present invention has been made in view of such a situation, and its purpose is to satisfactorily correct spherical aberration and astigmatism even when the total lens length is shortened as the lens unit becomes compact, and An object of the present invention is to provide a five-lens imaging lens capable of suppressing deterioration in image quality due to an eccentricity error, an imaging optical device and a digital device including the imaging lens.

In order to achieve the above object, the imaging lens of the first invention comprises, in order from the object side, a first lens having a positive refractive power and having a convex surface facing the object side, and a second lens having a concave surface facing the object side. A lens, a third lens having a positive refractive power, a fourth lens having a positive or negative refractive power, and a fifth lens having a positive or negative refractive power, the first lens and the Each of the third lenses has at least one aspheric surface and satisfies the following conditional expression (1).
0.4 <f3 / f1 <1.9 (1)
However,
f1: focal length of the first lens,
f3: focal length of the third lens
It is.

The imaging lens of a second invention is characterized in that, in the first invention, the second lens has a negative refractive power and satisfies the following conditional expression (2).
0.3 <r2a / f2 <0.8 (2)
However,
r2a: radius of curvature of the object side surface of the second lens,
f2: focal length of the second lens,
It is.

An imaging lens according to a third aspect of the invention is characterized in that, in the first or second aspect of the invention, the following conditional expression (3) is satisfied.
0.05 <T12 / TL <0.20 (3)
However,
T12: distance on the optical axis between the first lens and the second lens,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.

An imaging lens according to a fourth invention is characterized in that, in any one of the first to third inventions, the following conditional expression (4) is satisfied.
0.7 <f1 / f <1.5 (4)
However,
f: focal length of the entire system,
f1: focal length of the first lens,
It is.

An imaging lens of a fifth invention is characterized in that, in any one of the first to fourth inventions, the following conditional expression (5) is satisfied.
0.5 <f3 / f <1.6 (5)
However,
f: focal length of the entire system,
f3: focal length of the third lens
It is.

  The imaging lens of a sixth invention is characterized in that, in any one of the first to fifth inventions, an aperture stop is provided between the first lens and the second lens.

The imaging lens of a seventh invention is characterized in that, in any one of the first to sixth inventions, the first lens satisfies the following conditional expression (6).
60 <v1 <100 (6)
However,
v1: Abbe number of the first lens,
It is.

An imaging lens according to an eighth invention is characterized in that, in any one of the first to seventh inventions, the second lens satisfies the following conditional expressions (7) and (8).
1.6 <N2 <2.1 (7)
15 <v2 <30 (8)
However,
N2: refractive index of the second lens with respect to d-line,
v2: Abbe number of the second lens,
It is.

The imaging lens of a ninth invention is characterized in that, in any one of the first to eighth inventions, the second lens satisfies the following conditional expression (9).
-0.08 <T2 / f2 <-0.02 (9)
However,
T2: thickness on the optical axis of the second lens,
f2: focal length of the second lens,
It is.

  An imaging lens of a tenth invention is characterized in that, in any one of the first to ninth inventions, a part of the first to fifth lenses is extended when focusing from infinity to the closest distance. And

An image pickup lens of an eleventh aspect of the invention is characterized in that, in the tenth aspect of the invention, the first lens to the fourth lens are integrally extended and the following conditional expression (10) is satisfied.
0.1 <T45 / TL <0.3 (10)
However,
T45: distance on the optical axis between the fourth lens and the fifth lens,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.

  The imaging lens of a twelfth aspect of the present invention is the imaging lens according to any one of the first to eleventh aspects, wherein the first lens has a meniscus shape that is convex on the object side, and the second lens is a meniscus shape that is convex on the image side. The fifth lens has a biconcave shape, the third lens has a biconvex shape or an image-side convex meniscus shape, the fourth lens has at least one aspheric surface and has a weak refractive power, Has at least one aspherical surface and has a meniscus shape or biconcave shape that is convex on the object side.

  The imaging lens of a thirteenth aspect of the present invention is the imaging lens of any one of the first to twelfth aspects, wherein the surface shape of at least one surface of the fifth lens has an inflection point at a position other than the intersection with the optical axis. It is an aspherical shape.

  In the imaging lens of a fourteenth aspect according to any one of the first to thirteenth aspects, the surface shape of the image side surface of the second lens has an inflection point at a position other than the intersection with the optical axis. It is characterized by a spherical shape.

  The imaging lens of a fifteenth aspect of the present invention is the imaging lens according to any one of the first to fourteenth aspects, wherein the surface shape of at least one surface of the fourth lens has an inflection point at a position other than the intersection with the optical axis. It is an aspherical shape.

The imaging lens of a sixteenth aspect of the invention is characterized in that, in any one of the first to fifteenth aspects of the invention, the following conditional expression (11) is satisfied.
0.4 <Y '/ TL <0.8 (11)
However,
Y ': Maximum image height,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.

  An image pickup optical apparatus according to a seventeenth aspect includes an image pickup lens according to any one of the first to sixteenth aspects, and an image pickup element that converts an optical image formed on the light receiving surface into an electrical signal. And the imaging lens is provided so that an optical image of a subject is formed on a light receiving surface of the imaging device.

  A digital device according to an eighteenth aspect of the invention is characterized in that at least one of a still image shooting and a moving image shooting of a subject is added by including the imaging optical device according to the seventeenth aspect of the invention.

  According to a nineteenth aspect of the present invention, in the eighteenth aspect, a digital apparatus includes an image processing unit that electrically processes image data obtained from the imaging optical device.

  According to a twentieth aspect of the invention, in the nineteenth aspect of the invention, the image processing unit corrects image distortion.

  According to a twenty-first aspect of the present invention, in the nineteenth aspect of the invention, the depth of focus is increased by the image processing unit.

  A digital device according to a twenty-second aspect of the present invention is the mobile device according to any one of the eighteenth to twenty-first aspects.

  By adopting the configuration of the present invention, even when the total lens length is shortened as the lens unit becomes compact, spherical aberration and astigmatism are corrected well, and image quality deterioration due to decentration error is suppressed. An imaging lens having a five-lens configuration and an imaging optical apparatus including the imaging lens can be realized. By using the imaging optical device according to the present invention in a digital device such as a mobile phone or a portable information terminal, a high-performance image input function can be added to the digital device in a compact manner.

The optical block diagram of 1st Embodiment (Example 1). The optical block diagram of 2nd Embodiment (Example 2). The optical block diagram of 3rd Embodiment (Example 3). The optical block diagram of 4th Embodiment (Example 4). The optical block diagram of 5th Embodiment (Example 5). The optical block diagram of 6th Embodiment (Example 6). FIG. 6 is an aberration diagram of Example 1. FIG. 6 is an aberration diagram of Example 2. FIG. 6 is an aberration diagram of Example 3. FIG. 6 is an aberration diagram of Example 4. FIG. 6 is an aberration diagram of Example 5. FIG. 10 is an aberration diagram of Example 6. The schematic diagram which shows the schematic structural example of the digital apparatus with an image input function which concerns on this invention.

Hereinafter, an imaging lens, an imaging optical device, and a digital device according to the present invention will be described. An imaging lens according to the present invention has, in order from the object side, a first lens having a positive refractive power and a convex surface facing the object side, a second lens having a concave surface facing the object side, and a positive refractive power. An aspherical surface including a third lens, a fourth lens having a positive or negative refractive power, and a fifth lens having a positive or negative refractive power, each of the first lens and the third lens having at least one surface. have. And it is characterized by satisfying the following conditional expression (1).
0.4 <f3 / f1 <1.9 (1)
However,
f1: focal length of the first lens,
f3: focal length of the third lens
It is.

  By adopting a configuration in which positive optical power is shared between the first lens and the third lens as described above, it is possible to greatly suppress the eccentricity error sensitivity when the height is reduced. Further, by suppressing the power of the first lens, the object side surface of the second lens that is incident at a steep angle is made concave, and the angle formed by the upper ray and the normal of the surface is reduced, thereby suppressing the occurrence of off-axis aberrations. Making the object side surface of the second lens concave is an advantageous configuration for securing the peripheral light amount. Furthermore, by arranging the 4th and 5th lenses, it is possible to satisfactorily correct peripheral optical performance, particularly field curvature and distortion associated with low profile and wide angle, and to suppress the sensor incident angle. Can do. Further, spherical aberration correction is effectively performed by having the aspherical surface in the first lens, and astigmatism correction is effectively performed by having the aspherical surface in the third lens.

  Conditional expression (1) defines a preferable condition range regarding the power ratio between the first lens and the third lens. If the upper limit or lower limit of conditional expression (1) is exceeded, in either case, the power of one of the lenses becomes too strong and the eccentricity error sensitivity becomes severe. As a result, an asymmetric blur in the screen, called on-axis coma aberration or one-sided blur, occurs, leading to degradation of image quality.

  According to the above-mentioned characteristic configuration, spherical aberration and astigmatism are corrected well even when the total length of the lens unit is shortened due to the compactness of the lens unit, although it is smaller than the conventional type, and it is accompanied by an eccentric error. It is possible to realize a five-lens imaging lens capable of suppressing deterioration in image quality and an imaging optical apparatus including the imaging lens. If the imaging optical device is used in a digital device such as a mobile phone or a portable information terminal, it is possible to add a high-performance image input function to the digital device in a compact manner. It can contribute to functionalization. The conditions for achieving such effects in a well-balanced manner and achieving higher optical performance, downsizing, etc. will be described below.

It is desirable that the second lens has a negative refractive power and satisfies the following conditional expression (2).
0.3 <r2a / f2 <0.8 (2)
However,
r2a: radius of curvature of the object side surface of the second lens,
f2: focal length of the second lens,
It is.

  Since the second lens has negative power, axial chromatic aberration can be corrected and the Petzval sum can be reduced. If the upper limit of conditional expression (2) is exceeded, the angle formed by the upper ray and the normal of the object side surface of the second lens will become tight, making it difficult to suppress astigmatism. If the lower limit of conditional expression (2) is not reached, the correction of axial chromatic aberration will be insufficient.

It is desirable to satisfy the following conditional expression (3).
0.05 <T12 / TL <0.20 (3)
However,
T12: distance on the optical axis between the first lens and the second lens,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.

  If the upper limit of conditional expression (3) is exceeded, the spherical aberration becomes insufficiently corrected, so that it is necessary to reduce the power of the positive lens, and it becomes difficult to keep the total optical length compact. Conversely, if the lower limit of conditional expression (3) is not reached, the Petzval sum will increase and the astigmatic difference will increase.

It is desirable to satisfy the following conditional expression (4).
0.7 <f1 / f <1.5 (4)
However,
f: focal length of the entire system,
f1: focal length of the first lens,
It is.

  If the lower limit of conditional expression (4) is not reached, the power of the first lens becomes too strong and the eccentricity error sensitivity becomes severe. As a result, an asymmetric blur in the screen, called on-axis coma aberration or one-sided blur, occurs, leading to degradation of image quality. Further, if it is attempted to reduce such image quality deterioration, it is necessary to adjust the optical axis between the lenses, leading to an increase in cost. On the other hand, if the upper limit of conditional expression (4) is exceeded, the angle formed by the lower ray and the normal of the second lens object side surface becomes too large, increasing coma and astigmatism.

It is desirable to satisfy the following conditional expression (5).
0.5 <f3 / f <1.6 (5)
However,
f: focal length of the entire system,
f3: focal length of the third lens
It is.

  If the lower limit of conditional expression (5) is not reached, the power of the third lens becomes too strong and the eccentricity error sensitivity becomes severe. As a result, an asymmetric blur in the screen, called on-axis coma aberration or one-sided blur, occurs, leading to degradation of image quality. Further, if it is attempted to reduce such image quality deterioration, it is necessary to adjust the optical axis between the lenses, leading to an increase in cost. On the other hand, if the upper limit of conditional expression (5) is exceeded, the optical power of the first lens becomes too strong, the decentration error sensitivity increases, and axial coma and one-sided blur occur.

  It is desirable to have an aperture stop between the first lens and the second lens. By disposing the aperture stop between the first lens and the second lens, the angle formed by the upper ray of the first lens and the second lens and the normal of the surface can be reduced. This makes it easier to suppress the occurrence of off-axis aberrations.

The first lens preferably satisfies the following conditional expression (6).
60 <v1 <100 (6)
However,
v1: Abbe number of the first lens,
It is.

  If the upper limit of conditional expression (6) is exceeded, only low refractive index materials can be selected, so trying to obtain the same power will reduce the radius of curvature, leading to worsening off-axis aberrations and increasing error sensitivity. . On the other hand, if the lower limit of conditional expression (6) is not reached, the correction of axial chromatic aberration will be insufficient, resulting in image quality deterioration due to a decrease in contrast.

It is desirable that the second lens satisfies the following conditional expressions (7) and (8).
1.6 <N2 <2.1 (7)
15 <v2 <30 (8)
However,
N2: refractive index of the second lens with respect to d-line,
v2: Abbe number of the second lens,
It is.

  If the upper limit of conditional expression (7) is exceeded, only highly dispersed materials can be selected, making it difficult to correct chromatic aberration. It also leads to a significant cost increase of the lens material. On the other hand, if the lower limit of conditional expression (7) is not reached, the radius of curvature will be reduced if the same power is obtained, and the wall thickness ratio will be increased, resulting in welds, birefringence, and refractive index distribution. .

  If the upper limit of conditional expression (8) is exceeded, it will be difficult to correct longitudinal chromatic aberration. Conversely, if the lower limit of conditional expression (8) is not reached, it will be difficult to correct lateral chromatic aberration.

The second lens preferably satisfies the following conditional expression (9).
-0.08 <T2 / f2 <-0.02 (9)
However,
T2: thickness on the optical axis of the second lens,
f2: focal length of the second lens,
It is.

  If the upper limit of conditional expression (9) is exceeded, the lens strength becomes insufficient, causing cracks and changes in surface shape when holding the lens. In addition, the surface shape is deformed by the film stress when the antireflection film is coated, and the curvature of field increases. On the other hand, if the lower limit of conditional expression (9) is not reached, the Petzval sum increases, and the astigmatic difference increases.

  At the time of focusing from infinity to the closest distance, it is desirable to extend a part of the imaging lens, that is, a part of the first to fifth lenses.

  If a configuration in which a part of the imaging lens is extended at the time of focusing from infinity to the closest distance, the load on the lens driving device can be reduced and the size of the driving device can be reduced. Therefore, the module size can be made compact.

It is desirable that the first lens to the fourth lens are extended integrally and the following conditional expression (10) is satisfied.
0.1 <T45 / TL <0.3 (10)
However,
T45: distance on the optical axis between the fourth lens and the fifth lens,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.

  If the first lens to the fourth lens are integrally fed out during focusing from infinity to the closest distance, the field curvature fluctuation at the time of proximity can be greatly suppressed. If the upper limit of conditional expression (10) is exceeded, the field curvature correction effect of the fourth lens will be diminished, leading to a decrease in peripheral performance as the height is lowered. On the other hand, if the lower limit of conditional expression (10) is not reached, it will interfere with the lens frame when the position error of the lens driving device and the position error of the lens group due to individual variations are taken into account.

  The first lens has an object-side convex meniscus shape, the second lens has an image-side convex meniscus shape or biconcave shape, and the third lens has a biconvex shape or image-side convex meniscus shape, It is desirable that the fourth lens has at least one aspheric surface and has a weak refractive power, and the fifth lens has at least one aspheric surface and has an object-side convex meniscus shape or biconcave shape. That is, the imaging lens includes, in order from the object side, a first meniscus lens having a positive refractive power, a convex meniscus shape, a second lens having a convex meniscus shape or biconcave shape, and a biconvex shape or image. A third lens having a side-convex meniscus shape and positive refractive power, a fourth lens having at least one aspherical surface and weak refractive power, and a meniscus having at least one aspherical surface and convex on the object side It is desirable to comprise from the 5th lens which has a shape or a biconcave shape. However, the above shape is a paraxial surface shape. Even when the paraxial deviates from the described shape, there is no limit to the case where the aspherical surface is regarded as substantially the described shape.

  By making the first lens have a meniscus shape that is convex on the object side, the overall length of the lens can be shortened. By forming the second lens to have an image-side convex meniscus shape or biconcave shape, it is possible to suppress the occurrence of off-axis aberrations and to secure the peripheral light amount. By making the third lens a biconvex shape or an image-side convex meniscus shape, it is possible to reduce the eccentricity error sensitivity and to make the incident angle with respect to the imaging surface close to telecentricity. By having at least one aspherical surface in each of the fourth and fifth lenses, it is possible to achieve both of the sensor incident angle and distortion correction. By making the fifth lens into a meniscus shape or a biconcave shape that is convex on the object side, the overall length can be shortened.

  The surface shape of at least one surface of the fifth lens is preferably an aspheric shape having an inflection point at a position other than the intersection with the optical axis. By adopting an aspherical shape having an inflection point at a position other than the intersection with the optical axis on at least one surface of the fifth lens, the sensor incident angle can be made close to telecentric.

  The surface shape of the image side surface of the second lens is preferably an aspherical shape having an inflection point at a position other than the intersection with the optical axis. By adopting an aspherical shape having an inflection point at a position other than the intersection with the optical axis on the image side surface of the second lens, it is possible to suppress a decrease in peripheral light amount.

  The surface shape of at least one surface of the fourth lens is preferably an aspheric shape having an inflection point at a position other than the intersection with the optical axis. By adopting an aspherical shape having an inflection point at a position other than the intersection with the optical axis on at least one surface of the fourth lens, it is possible to satisfactorily correct distortion.

It is desirable to satisfy the following conditional expression (11).
0.4 <Y '/ TL <0.8 (11)
However,
Y ': Maximum image height,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.

  If the upper limit of conditional expression (11) is exceeded, the eccentricity error sensitivity will be significantly higher, and one-sided blur will increase, so if you try to suppress this, multiple adjustments will be required, and productivity will be significantly reduced. . On the other hand, if the lower limit of conditional expression (11) is not reached, the lens outer diameter increases, so that it is difficult to ensure surface accuracy over the entire effective diameter, and field curvature due to manufacturing errors increases.

  The imaging lens according to the present invention is suitable for use as an imaging lens for a digital device with an image input function, and by combining this with an imaging device or the like, an image of a subject is optically captured and used as an electrical signal. An imaging optical device that outputs can be configured. The imaging optical device is an optical device that constitutes a main component of a camera used for still image shooting and moving image shooting of a subject, for example, an imaging lens that forms an optical image of an object in order from the object (i.e., subject) side, and And an imaging device that converts an optical image formed by the imaging lens into an electrical signal.

  Examples of the camera include a digital camera, a video camera, a surveillance camera, an in-vehicle camera, a videophone camera, and the like, and a personal computer, a portable information device (for example, a mobile computer, a cellular phone, a portable information terminal, etc.) And portable information device terminals), peripheral devices (scanners, printers, etc.), and other digital devices. As can be seen from these examples, it is possible not only to configure a camera by using an imaging optical device, but also to add a camera function by mounting the imaging optical device on various digital devices. For example, a digital device with an image input function such as a mobile phone with a camera can be configured.

  FIG. 13 is a schematic cross-sectional view illustrating a schematic configuration example of a digital device DU having an image input function. The imaging optical device LU mounted on the digital device DU shown in FIG. 13 includes an imaging lens LN (AX: optical axis) that forms an optical image (image plane) IM of the object in order from the object (namely, subject) side, Formed on the light receiving surface SS by a parallel plane plate PT (optical filters such as an optical low-pass filter and an infrared cut filter arranged as necessary; corresponding to a cover glass of the image sensor SR) and an imaging lens LN. And an image sensor SR that converts the optical image IM into an electrical signal. When a digital device DU with an image input function is constituted by this imaging optical device LU, the imaging optical device LU is usually arranged inside the body, but when necessary to realize the camera function, a form as necessary is adopted. Is possible. For example, the unitized imaging optical device LU can be configured to be detachable or rotatable with respect to the main body of the digital device DU.

  As the image sensor SR, for example, a solid-state image sensor such as a CCD image sensor or a CMOS image sensor having a plurality of pixels is used. Since the imaging lens LN is provided so that an optical image IM of the subject is formed on the light receiving surface SS of the imaging element SR, the optical image IM formed by the imaging lens LN is electrically converted by the imaging element SR. Converted to a signal.

  The digital device DU includes a signal processing unit 1, a control unit 2, a memory 3, an operation unit 4, a display unit 5 and the like in addition to the imaging optical device LU. The signal generated by the image sensor SR is subjected to predetermined digital image processing, image compression processing, and the like in the signal processing unit 1 as necessary, and is recorded in the memory 3 (semiconductor memory, optical disk, etc.) as a digital video signal, In some cases, the signal is transmitted to another device through a cable or converted into an infrared signal. The control unit 2 is composed of a microcomputer, and performs control of functions such as a photographing function (still image photographing function, moving image photographing function, etc.), an image reproduction function, etc .; control of a lens moving mechanism for focusing, and the like. For example, the control unit 2 controls the imaging optical device LU so as to perform at least one of still image shooting and moving image shooting of a subject. The display unit 5 includes a display such as a liquid crystal monitor, and displays an image using an image signal converted by the image sensor SR or image information recorded in the memory 3. The operation unit 4 includes operation members such as an operation button (for example, a release button) and an operation dial (for example, a shooting mode dial), and transmits information input by the operator to the control unit 2.

  The signal processing unit 1 includes an image processing unit 1a that electrically processes image data obtained from the imaging optical device. By having the image processing unit 1a, it is possible to reduce aberrations that cannot be optically corrected and a decrease in peripheral light amount.

  It is desirable to correct image distortion by the image processing unit 1a. By correcting the distortion of the image, the aberration burden due to the lens close to the image plane is particularly reduced, so that the exit pupil position can be easily controlled, and the lens shape can be made to have a good workability.

  It is desirable to increase the depth of focus by the image processing unit 1a. By increasing the depth of focus, it becomes possible to tolerate component variations, so that productivity can be increased. Further, when a driving device is used, it is possible to absorb a position error and an eccentricity error of the driving device.

  As described above, the imaging lens LN includes, in order from the object side, a first lens L1 having a positive refractive power and having a convex surface facing the object side, a second lens L2 having a concave surface facing the object side, and a positive lens. The image pickup device has a five-lens configuration including a third lens L3 having a refractive power, a fourth lens L4 having a positive or negative refractive power, and a fifth lens L5 having a positive or negative refractive power. An optical image IM is formed on the light receiving surface SS of the SR. The optical image to be formed by the imaging lens LN is, for example, an optical low-pass filter (corresponding to the parallel flat plate PT in FIG. 13) having a predetermined cutoff frequency characteristic determined by the pixel pitch of the imaging element SR. By passing, the spatial frequency characteristic is adjusted so that so-called aliasing noise generated when converted into an electrical signal is minimized. Thereby, generation | occurrence | production of a color moire can be suppressed. However, if the performance around the resolution limit frequency is suppressed, there is no need to worry about the occurrence of noise without using an optical low-pass filter, and the display system where the noise is not very noticeable (for example, the liquid crystal of a mobile phone) When the user uses the screen or the like to perform shooting or viewing, it is not necessary to use an optical low-pass filter.

  Next, the specific optical configuration of the imaging lens LN will be described in more detail with reference to the first to sixth embodiments. 1 to 6 show first to sixth embodiments of the imaging lens LN (single focus lens) in an infinitely focused state in optical cross sections, respectively. Further, the movement of the focus group during focusing from infinity to the closest distance is indicated by an arrow mF in FIGS.

  The imaging lens LN (FIG. 1) of the first embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative The fourth lens L4 and the negative fifth lens L5. The plane parallel plate PT disposed on the image side of the imaging lens LN is assumed to be an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. All the lens surfaces constituting the imaging lens LN are assumed to be aspherical surfaces. The first lens L1 is assumed to be a glass material, and the second to fifth lenses L2 to L5 are assumed to be optical materials. In addition, it is assumed that partial group extension is performed in which the focal position is adjusted by moving the first lens L1 to the fourth lens L4 in an integrated manner for autofocusing, macro switching function, or the like. Of course, a plastic lens may be used as the first lens L1 by allowing axial chromatic aberration.

  The imaging lens LN (FIG. 2) of the second embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative The fourth lens L4 and the negative fifth lens L5. The plane parallel plate PT disposed on the image side of the imaging lens LN is assumed to be an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. All the lens surfaces constituting the imaging lens LN are assumed to be aspherical surfaces. The first lens L1 is assumed to be a glass material, and the second to fifth lenses L2 to L5 are assumed to be optical materials. In addition, it is assumed that partial group extension is performed in which the focal position is adjusted by moving the first lens L1 to the fourth lens L4 in an integrated manner for autofocusing, macro switching function, or the like. Of course, a plastic lens may be used as the first lens L1 by allowing axial chromatic aberration.

  The imaging lens LN (FIG. 3) of the third embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a positive The fourth lens L4 and the negative fifth lens L5. The plane parallel plate PT disposed on the image side of the imaging lens LN is assumed to be an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. All the lens surfaces constituting the imaging lens LN are assumed to be aspherical surfaces. The first lens L1 is assumed to be a glass material, and the second to fifth lenses L2 to L5 are assumed to be optical materials. In addition, it is assumed that partial group extension is performed in which the focal position is adjusted by moving the first lens L1 to the fourth lens L4 in an integrated manner for autofocusing, macro switching function, or the like. Of course, a plastic lens may be used as the first lens L1 by allowing axial chromatic aberration.

  The imaging lens LN (FIG. 4) of the fourth embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative The fourth lens L4 and the negative fifth lens L5. The plane parallel plate PT disposed on the image side of the imaging lens LN is assumed to be an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. All the lens surfaces constituting the imaging lens LN are assumed to be aspherical surfaces. The first lens L1 is assumed to be a glass material, and the second to fifth lenses L2 to L5 are assumed to be optical materials. In addition, it is assumed that partial group extension is performed in which the focal position is adjusted by moving the first lens L1 to the fourth lens L4 in an integrated manner for autofocusing, macro switching function, or the like. Of course, a plastic lens may be used as the first lens L1 by allowing axial chromatic aberration.

  The imaging lens LN (FIG. 5) of the fifth embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative The fourth lens L4 and the negative fifth lens L5. The plane parallel plate PT disposed on the image side of the imaging lens LN is assumed to be an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. All the lens surfaces constituting the imaging lens LN are assumed to be aspherical surfaces. The first lens L1 is assumed to be a glass material, and the second to fifth lenses L2 to L5 are assumed to be optical materials. In addition, it is assumed that partial group extension is performed in which the focal position is adjusted by moving the first lens L1 to the fourth lens L4 in an integrated manner for autofocusing, macro switching function, or the like. Of course, a plastic lens may be used as the first lens L1 by allowing axial chromatic aberration.

  The imaging lens LN (FIG. 6) according to the sixth embodiment includes, in order from the object side, the aperture stop ST, the positive first lens L1, the positive second lens L2, the positive third lens L3, and the negative. The fourth lens L4 and the negative fifth lens L5. The plane parallel plate PT disposed on the image side of the imaging lens LN is assumed to be an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, or the like. All the lens surfaces constituting the imaging lens LN are assumed to be aspherical surfaces. The first lens L1 is assumed to be a glass material, and the second to fifth lenses L2 to L5 are assumed to be optical materials. Further, it is assumed that the entire group is extended by moving the first lens L1 to the fifth lens L5 as a unit for performing the focus position adjustment in the auto focus, the macro switching function, or the like. Of course, a plastic lens may be used as the first lens L1 by allowing axial chromatic aberration.

  As an optical material constituting the lens element of the imaging lens LN, it is preferable to use a plastic material having a small refractive index change due to a temperature change. Since the plastic material has a large refractive index change when the temperature changes, if all or most of the first lens L1 to the fifth lens L5 are made of plastic lenses, the image of the entire imaging lens LN system when the ambient temperature changes. The problem is that the point position will fluctuate. Recently, however, it has been found that mixing inorganic fine particles in a plastic material can reduce the effect of temperature changes on the plastic material. In other words, in general, mixing fine particles with a transparent plastic material causes light scattering and lowers the transmittance, making it difficult to use as an optical material. If it is made small, scattering can be prevented from substantially occurring.

In addition, the refractive index of the plastic material decreases as the temperature increases, but the refractive index of the inorganic particles increases as the temperature increases. Therefore, it is possible to make almost no change in the refractive index by using these temperature dependencies so as to cancel each other. Specifically, by dispersing inorganic particles having a maximum length of 20 nanometers or less in a plastic material as a base material, a plastic material with extremely low temperature dependency of the refractive index is obtained. For example, by dispersing fine particles of niobium oxide (Nb ₂ O ₅ ) in an acrylic resin, a change in refractive index due to a temperature change can be reduced. In the imaging lens LN according to the present invention, the plastic lens in which such inorganic particles are dispersed is used for the positive lens (L1) having a relatively large refractive power or a lens having a relatively large refractive power, so that the entire imaging lens LN can be used. It is possible to suppress the image point position fluctuation at the time of temperature change to be small.

  Also, in recent years, as a method for mounting image pickup optical devices at low cost and in large quantities, reflow processing (IC (Integrated Circuit) chips and other electronic components and optical elements are placed on a substrate on which solder has been potted in advance ( A technique has been proposed in which an electronic component and an optical element are simultaneously mounted on a substrate by performing a heat treatment) and melting solder. In order to perform mounting using such a reflow process, it is necessary to heat the optical element together with the electronic components to about 200 to 260 degrees. However, there is a problem that a lens using a thermoplastic resin is thermally deformed or discolored at such a high temperature and its optical performance is deteriorated. As one of the methods for solving such a problem, a technology has been proposed that uses a glass mold lens having excellent heat resistance and achieves both miniaturization and optical performance in a high temperature environment. Since the cost is higher than the lens used, there is a problem in that it cannot meet the demand for cost reduction of the imaging optical device.

  When an energy curable resin is used as a material for the imaging lens (here, the energy curable resin refers to both a thermosetting resin and an ultraviolet curable resin), a polycarbonate-based or polyolefin-based material. Compared to the case where such a thermoplastic resin is used, since the deterioration of the optical performance when the imaging lens is exposed to a high temperature is small, it is effective for the reflow process. In addition, since it is easier to manufacture and cheaper than a glass mold lens, it is possible to achieve both cost reduction and improvement in mass productivity of an imaging optical device incorporating the imaging lens. Therefore, it is preferable to use a plastic lens formed of an energy curable resin as the plastic lens used for the imaging lens LN according to the present invention.

  In each of the above-described embodiments and each example to be described later, the principal ray incident angle of the light beam incident on the imaging surface of the solid-state imaging device is not necessarily designed to be sufficiently small in the periphery of the imaging surface. However, with recent technology, it has become possible to reduce shading by reviewing the arrangement of the color filters of the solid-state imaging device and the on-chip microlens array. Specifically, if the pitch of the arrangement of the color filters and the on-chip microlens array is set slightly smaller than the pixel pitch of the image pickup surface of the image pickup device, the color filter for each pixel becomes closer to the periphery of the image pickup surface. Since the on-chip microlens array is shifted to the optical axis side of the imaging lens, the obliquely incident light beam can be efficiently guided to the light receiving portion of each pixel. Thereby, the shading which generate | occur | produces with a solid-state image sensor can be suppressed small. In each embodiment to be described later, a design example aiming at further miniaturization is provided for the portion in which the requirement is relaxed.

  As can be understood from the above description, the following configurations are included in each of the above-described embodiments and each example described later. With this configuration, even when the total lens length is shortened due to the compactness of the lens unit, it is possible to satisfactorily correct spherical aberration and astigmatism and to suppress image quality deterioration due to decentration error. The imaging lens and an imaging optical device including the imaging lens can be realized. By using the imaging optical device in a digital device such as a mobile phone or a portable information terminal, a high-performance image input function can be added to the digital device in a compact manner.

  (i) In order from the object side, a first lens having positive optical power and having a convex surface facing the object side, a second lens having a concave surface facing the object side, and a third lens having positive optical power And a fourth lens having a positive or negative optical power and a fifth lens having a positive or negative optical power, and satisfying the conditional expression (1) Imaging lens.

  (ii) The imaging lens according to (i), wherein the second lens has negative optical power and satisfies the conditional expression (2).

  (iii) The imaging lens according to (i) or (ii), wherein at least one of the conditional expressions (3) to (6), (9), and (11) is satisfied.

  (iv) The imaging lens according to any one of (i) to (iii), wherein an aperture stop is provided between the first lens and the second lens.

  (v) The imaging lens according to any one of (i) to (iv), wherein the conditional expressions (7) and (8) are satisfied.

  (vi) The imaging lens according to any one of (i) to (v), wherein a part of the first to fifth lenses is extended during focusing from infinity to the closest distance.

  (vii) The imaging lens according to (vi), wherein the first lens to the fourth lens are integrally extended to satisfy the conditional expression (10).

  (viii) The first lens has an object-side convex meniscus shape, the second lens has an image-side convex meniscus shape or biconcave shape, and the third lens has a biconvex shape or image-side convex shape. It has a meniscus shape, the fourth lens has at least one aspheric surface and weak optical power, and the fifth lens has at least one aspheric surface and has a convex object side meniscus shape or biconcave shape. The imaging lens according to any one of (i) to (vii), characterized by comprising:

  (ix) Any one of (i) to (viii) is characterized in that the surface shape of at least one surface of the fifth lens is an aspheric shape having an inflection point at a position other than the intersection with the optical axis. The imaging lens according to Item 1.

  (x) Any one of (i) to (ix), wherein the surface shape of the image side surface of the second lens is an aspherical shape having an inflection point at a position other than the intersection with the optical axis. The imaging lens described in the item.

  (xi) Any one of (i) to (x), wherein the surface shape of at least one surface of the fourth lens is an aspherical shape having an inflection point at a position other than the intersection with the optical axis. The imaging lens according to Item 1.

  (xii) The imaging lens according to any one of (i) to (xi), and an imaging device that converts an optical image formed on the light receiving surface into an electrical signal, An imaging optical apparatus, wherein the imaging lens is provided so that an optical image of a subject is formed on a light receiving surface.

  (xiii) A digital device provided with the imaging optical device according to (xii), to which at least one function of still image shooting and moving image shooting of a subject is added.

  (xiv) The digital apparatus according to (xiii), further including an image processing unit that electrically processes image data obtained from the imaging optical device.

  (xv) The digital device according to (xiv), wherein the image processing unit corrects image distortion.

  (xvi) The digital device according to (xiv), wherein the image processing unit increases a depth of focus.

  (xvii) The digital device according to any one of (xiii) to (xvi), which is a mobile phone, a portable information terminal, a personal computer, a mobile computer, or a peripheral device thereof.

  Hereinafter, the configuration and the like of the imaging lens embodying the present invention will be described more specifically with reference to the construction data of the examples. Examples 1 to 6 listed here are numerical examples corresponding to the first to sixth embodiments, respectively, and are optical configuration diagrams showing the first to sixth embodiments (FIGS. 1 to 6). 6) shows the lens configurations of the corresponding Examples 1 to 6, respectively.

In the construction data of each example, as surface data, in order from the left column, the surface number, the radius of curvature r (mm), the surface spacing d (mm) on the axis, and the refractive index nd regarding the d-line (wavelength 587.56 nm). , D line, Abbe number vd. The surface with * in the surface number is an aspheric surface, and the surface shape is defined by the following formula (AS) using the local Cartesian coordinate system (x, y, z) with the surface vertex as the origin. . As aspheric data, an aspheric coefficient or the like is shown. It should be noted that the coefficient of the term not described in the aspherical data of each embodiment is 0, and en = × 10 ⁻ⁿ for all data.
z = (c · h ² ) / [1 + √ {1− (1 + K) · c ² · h ² }] + Σ (Aj · h ^j )… (AS)
However,
h: height (h ² = x ² + y ² ) in the direction perpendicular to the z-axis (optical axis AX)
z: The amount of sag in the direction of the optical axis AX at the position of height h (based on the surface vertex),
c: curvature at the surface vertex (the reciprocal of the radius of curvature r),
K: conic constant,
Aj: j-th order aspheric coefficient,
It is.

  Various data include focal length (f, mm), F number (Fno.), Half angle of view (ω, °), image height (y'max, mm), total lens length (TL, mm), back focus (BF , Mm). The F number, half field angle, and back focus are effective values at the entire lens length and object distance (∞). The back focus expresses the distance from the last lens surface to the paraxial image surface in terms of air length, and the total lens length is the distance from the front lens surface to the last lens surface plus the back focus. . Furthermore, as single lens data, the focal length of each lens is shown, and the values of the examples corresponding to the respective conditional expressions are shown in Table 1.

  FIGS. 7 to 12 are aberration diagrams (focused state at infinity) of Examples 1 to 6 (EX1 to 6). 7A to 12B, (A) is a spherical aberration diagram, (B) is an astigmatism diagram, and (C) is a distortion diagram. The spherical aberration diagram shows the amount of spherical aberration with respect to the d-line (wavelength 587.56 nm) indicated by the solid line, the amount of spherical aberration with respect to the C-line (wavelength 656.28 nm) indicated by the alternate long and short dash line, and the amount of spherical aberration with respect to the g-line (wavelength 435.84 nm) indicated by the broken line. Is represented by the amount of deviation in the optical axis AX direction from the paraxial image plane (unit: mm, horizontal axis scale: -0.100 to 0.100 mm), and the vertical axis represents the incident height to the pupil at its maximum height. The value normalized by (ie, relative pupil height). In the astigmatism diagram, the four-dot chain line Y is the tangential image plane with respect to the d line, the solid line X is the sagittal image plane with respect to the d line, and the amount of deviation from the paraxial image plane in the optical axis AX direction Scale: -0.100 to 0.100 mm), and the vertical axis represents the image height (IMG HT, unit: mm). In the distortion diagram, the horizontal axis represents distortion (unit:%, horizontal axis scale: -5.0 to 5.0%) with respect to the d-line, and the vertical axis represents image height (IMG HT, unit: mm). The maximum value of the image height IMG HT corresponds to the maximum image height y′max (half the diagonal length of the light receiving surface SS of the image sensor SR) on the image plane IM.

  The imaging lens LN (FIG. 1) according to the first exemplary embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative fourth lens. The lens L4 includes a negative fifth lens L5. When viewing each lens with a paraxial surface shape, the first lens L1 is a positive meniscus lens convex toward the object side, the second lens L2 is a biconcave negative lens, and the third lens L3 is biconvex. The fourth lens L4 is a negative meniscus lens concave on the image side, and the fifth lens L5 is a biconcave negative lens.

  The imaging lens LN (FIG. 1) of the second embodiment includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative fourth lens. The lens L4 includes a negative fifth lens L5. When viewing each lens with a paraxial surface shape, the first lens L1 is a positive meniscus lens convex on the object side, the second lens L2 is a biconcave negative lens, and the third lens L3 is on the image side. The fourth lens L4 is a negative meniscus lens concave on the image side, and the fifth lens L5 is a negative meniscus lens concave on the image side.

  The imaging lens LN (FIG. 3) of Embodiment 3 includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a positive fourth lens. The lens L4 includes a negative fifth lens L5. When viewing each lens with a paraxial surface shape, the first lens L1 is a positive meniscus lens convex toward the object side, the second lens L2 is a negative meniscus lens concave toward the object side, and the third lens L3 is It is a biconvex positive lens, the fourth lens L4 is a positive meniscus lens convex to the image side, and the fifth lens L5 is a biconcave negative lens.

  The imaging lens LN (FIG. 4) of Example 4 includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative fourth lens. The lens L4 includes a negative fifth lens L5. When viewing each lens with a paraxial surface shape, the first lens L1 is a positive meniscus lens convex toward the object side, the second lens L2 is a negative meniscus lens concave toward the object side, and the third lens L3 is It is a biconvex positive lens, the fourth lens L4 is a negative meniscus lens concave on the object side, and the fifth lens L5 is a biconcave negative lens.

  The imaging lens LN (FIG. 5) of Embodiment 5 includes, in order from the object side, a positive first lens L1, an aperture stop ST, a negative second lens L2, a positive third lens L3, and a negative fourth lens. The lens L4 includes a negative fifth lens L5. When viewing each lens with a paraxial surface shape, the first lens L1 is a positive meniscus lens convex toward the object side, the second lens L2 is a negative meniscus lens concave toward the object side, and the third lens L3 is The fourth lens L4 is a negative meniscus lens concave on the image side, and the fifth lens L5 is a negative meniscus lens concave on the image side.

  The imaging lens LN (FIG. 6) of Example 6 includes, in order from the object side, an aperture stop ST, a positive first lens L1, a positive second lens L2, a positive third lens L3, and a negative fourth lens. The lens L4 includes a negative fifth lens L5. When viewing each lens with a paraxial surface shape, the first lens L1 is a biconvex positive lens, the second lens L2 is a positive meniscus lens convex to the image side, and the third lens L3 is on the image side. It is a convex positive meniscus lens, the fourth lens L4 is a negative meniscus lens concave on the object side, and the fifth lens L5 is a negative meniscus lens concave on the image side.

Example 1
Unit: mm
Surface data surface number rd nd vd
Object ∞ ∞
1 * 3.093 0.518 1.58913 61.24
2 * 305.690 0.064
3 (Aperture) ∞ 0.414
4 * -3.524 0.350 1.63200 23.41
5 * 7160.168 0.158
6 * 5.164 1.139 1.54470 56.15
7 * -2.255 0.088
8 * 28.008 0.399 1.54470 56.15
9 * 6.700 1.152
10 * -102.361 0.619 1.54470 56.15
11 * 2.233 0.455
12 ∞ 0.145 1.51600 64.10
13 ∞ 0.498
Image plane ∞

Aspheric data 1st surface
K = -1.4241e + 000
A4 = -2.0579e-002
A6 = -6.5954e-003
A8 = -1.7022e-002
A10 = 1.5702e-002
A12 = -1.1341e-002
A14 = 2.2460e-003
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Second side
K = -5.3530e + 005
A4 = -4.6670e-002
A6 = -2.8532e-003
A8 = -2.8012e-002
A10 = 5.4124e-002
A12 = -5.2325e-002
A14 = 1.8235e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

4th page
K = -3.8460e + 000
A4 = -6.4781e-002
A6 = 1.1760e-001
A8 = -1.2550e-001
A10 = 8.2698e-002
A12 = 5.1957e-003
A14 = -3.3205e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

5th page
K = -2.4112e + 009
A4 = -1.0389e-001
A6 = 2.2431e-001
A8 = -2.4444e-001
A10 = 2.0334e-001
A12 = -9.9205e-002
A14 = 1.9871e-002
A16 = -7.3342e-004
A18 = -7.15304e-04
A20 = 6.00200e-04

6th page
K = -9.0503e + 001
A4 = -2.7118e-002
A6 = 2.8755e-002
A8 = -1.7438e-002
A10 = 5.2812e-003
A12 = -2.5675e-004
A14 = -1.9077e-004
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

7th page
K = -1.1139e-001
A4 = -1.3314e-002
A6 = -2.7155e-003
A8 = -9.1250e-004
A10 = -4.8037e-004
A12 = -8.5373e-005
A14 = 3.7482e-005
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

8th page
K = 0.0000e + 000
A4 = -2.2349e-002
A6 = -2.0542e-003
A8 = -3.1736e-003
A10 = 2.1273e-004
A12 = 2.4503e-005
A14 = -7.1008e-005
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

9th page
K = 0.0000e + 000
A4 = -1.3116e-002
A6 = -9.0098e-004
A8 = -5.2550e-004
A10 = -8.1182e-005
A12 = 2.7656e-005
A14 = -1.6089e-006
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

10th page
K = 0.0000e + 000
A4 = -1.2662e-001
A6 = 2.3965e-002
A8 = -1.9989e-003
A10 = -2.0814e-004
A12 = 9.4413e-005
A14 = -6.6522e-006
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

11th page
K = -8.8902e + 000
A4 = -4.5365e-002
A6 = 9.3394e-003
A8 = -1.4017e-003
A10 = 1.1564e-004
A12 = -4.8278e-006
A14 = 1.2485e-007
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Various data
f 4.748
Fno. 2.884
ω 37.952
y'max 3.528
TL 5.949
BF 1.049

Single lens Data lens (surface) Focal length
1 (1-2) 5.300
2 (4-5) -5.572
3 (6-7) 3.047
4 (8-9) -16.276
5 (10-11) -4.003

Example 2
Unit: mm
Surface data surface number rd nd vd
Object ∞ ∞
1 * 2.261 0.599 1.49700 81.61
2 * 17.101 0.083
3 (Aperture) ∞ 0.465
4 * -5.822 0.300 1.63200 23.41
5 * 119.558 0.329
6 * -9.822 0.650 1.54470 56.15
7 * -2.655 0.050
8 * 2.940 0.343 1.54470 56.15
9 * 2.800 1.577
10 * 2.936 0.497 1.54470 56.15
11 * 1.601 0.462
12 ∞ 0.145 1.51600 64.10
13 ∞ 0.500
Image plane ∞

Aspheric data 1st surface
K = -5.3681e-001
A4 = -1.2314e-002
A6 = -1.6830e-003
A8 = -2.0983e-002
A10 = 1.6036e-002
A12 = -9.7707e-003
A14 = 1.4262e-003
A16 = 0.0000e + 000

Second side
K = -2.6310e + 001
A4 = -4.3718e-002
A6 = -4.1628e-003
A8 = -3.3855e-002
A10 = 6.6268e-002
A12 = -6.0018e-002
A14 = 1.9371e-002
A16 = 0.0000e + 000

4th page
K = -6.4772e + 000
A4 = -1.2142e-001
A6 = 1.7112e-001
A8 = -1.7357e-001
A10 = 1.3369e-001
A12 = -1.8832e-003
A14 = -3.4049e-002
A16 = 0.0000e + 000

5th page
K = 3.0000e + 001
A4 = -1.3194e-001
A6 = 2.0835e-001
A8 = -2.1852e-001
A10 = 2.1379e-001
A12 = -1.0815e-001
A14 = 2.0009e-002
A16 = 0.0000e + 000

6th page
K = 2.9898e + 001
A4 = -7.5146e-002
A6 = 3.8199e-002
A8 = -1.6972e-002
A10 = 6.4850e-003
A12 = 6.6677e-004
A14 = -8.1568e-004
A16 = 0.0000e + 000

7th page
K = 6.6561e-001
A4 = -1.7217e-002
A6 = 3.3906e-003
A8 = -4.0611e-004
A10 = -4.2879e-004
A12 = -2.1012e-005
A14 = 9.2907e-005
A16 = 0.0000e + 000

8th page
K = -4.7651e + 000
A4 = -1.6896e-002
A6 = -1.3802e-003
A8 = -5.7897e-004
A10 = -7.0248e-005
A12 = 1.9740e-006
A14 = 5.5854e-006
A16 = 0.0000e + 000

9th page
K = -2.3017e + 000
A4 = -2.9771e-002
A6 = 2.6516e-003
A8 = -9.8206e-004
A10 = -3.5481e-005
A12 = 4.1573e-005
A14 = -5.2862e-006
A16 = 0.0000e + 000

10th page
K = -2.3122e-001
A4 = -1.2652e-001
A6 = 1.7626e-002
A8 = -5.3659e-004
A10 = -3.1023e-004
A12 = 5.0064e-005
A14 = -2.1117e-006
A16 = 0.0000e + 000

11th page
K = -3.2083e + 000
A4 = -6.5983e-002
A6 = 1.4650e-002
A8 = -2.1692e-003
A10 = 1.2719e-004
A12 = 1.5427e-007
A14 = -1.4184e-007
A16 = 0.0000e + 000

Various data
f 4.978
Fno. 2.884
ω 36.425
y'max 3.528
TL 5.945
BF 1.052

Single lens Data lens (surface) Focal length
1 (1-2) 5.174
2 (4-5) -8.776
3 (6-7) 6.474
4 (8-9) -789.336
5 (10-11) -7.435

Example 3
Unit: mm
Surface data surface number rd nd vd
Object ∞ ∞
1 * 2.135 0.598 1.49700 81.61
2 * 13.545 0.162
3 (Aperture) ∞ 0.656
4 * -3.501 0.329 1.63200 23.41
5 * -11.521 0.158
6 * 68.271 0.938 1.54470 56.15
7 * -2.398 0.127
8 * -94.737 0.443 1.54470 56.15
9 * -32.057 0.776
10 * -132.223 0.714 1.54470 56.15
11 * 2.032 0.455
12 ∞ 0.145 1.51600 64.10
13 ∞ 0.500
Image plane ∞

Aspheric data 1st surface
K = 1.6729e-003
A4 = -1.0713e-002
A6 = 4.4191e-003
A8 = -2.1542e-002
A10 = 1.6201e-002
A12 = -7.7222e-003
A14 = 9.1872e-005
A16 = -1.2784e-005
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Second side
K = -2.6368e + 002
A4 = -9.5553e-003
A6 = -4.4063e-004
A8 = -4.5467e-002
A10 = 6.7915e-002
A12 = -5.3927e-002
A14 = 1.5232e-002
A16 = 8.3129e-005
A18 = 0.0000e + 000
A20 = 0.0000e + 000

4th page
K = 2.0830e + 000
A4 = -7.1487e-002
A6 = 8.6489e-002
A8 = -9.9136e-002
A10 = 8.3769e-002
A12 = 1.4929e-002
A14 = -3.5659e-002
A16 = -5.8459e-012
A18 = 0.0000e + 000
A20 = 0.0000e + 000

5th page
K = -8.6112e + 002
A4 = -1.5506e-001
A6 = 2.2712e-001
A8 = -2.4947e-001
A10 = 2.1656e-001
A12 = -9.9920e-002
A14 = 2.2713e-002
A16 = -1.7452e-003
A18 = -1.48521e-03
A20 = 5.79015e-04

6th page
K = -1.7940e + 004
A4 = -5.7418e-002
A6 = 2.7385e-002
A8 = -1.0520e-002
A10 = 4.3837e-003
A12 = -8.5967e-004
A14 = 2.9806e-005
A16 = -6.8873e-006
A18 = 0.0000e + 000
A20 = 0.0000e + 000

7th page
K = -5.0980e-001
A4 = 8.9901e-004
A6 = -6.3698e-003
A8 = 5.6426e-004
A10 = 1.0295e-004
A12 = -1.0695e-004
A14 = -3.9675e-005
A16 = 2.3107e-006
A18 = 0.0000e + 000
A20 = 0.0000e + 000

8th page
K = 1.0649e + 003
A4 = -9.8754e-004
A6 = 1.6900e-003
A8 = -4.4959e-004
A10 = -1.3690e-004
A12 = -3.5259e-006
A14 = 6.7476e-006
A16 = 8.2404e-008
A18 = 0.0000e + 000
A20 = 0.0000e + 000

9th page
K = 0.0000e + 000
A4 = -1.5371e-002
A6 = 5.7771e-003
A8 = -7.9437e-004
A10 = -1.0255e-004
A12 = 2.2771e-005
A14 = 4.1317e-007
A16 = -3.1275e-008
A18 = 0.0000e + 000
A20 = 0.0000e + 000

10th page
K = 0.0000e + 000
A4 = -1.2833e-001
A6 = 2.8143e-002
A8 = -2.1536e-003
A10 = -2.7177e-004
A12 = 1.0244e-004
A14 = -8.0716e-006
A16 = -7.9169e-008
A18 = 0.0000e + 000
A20 = 0.0000e + 000

11th page
K = -8.4318e + 000
A4 = -3.9958e-002
A6 = 7.9396e-003
A8 = -1.1403e-003
A10 = 9.7414e-005
A12 = -4.6599e-006
A14 = 1.1632e-007
A16 = -2.7103e-010
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Various data
f 4.890
Fno. 2.884
ω 37.198
y'max 3.528
TL 5.952
BF 1.052

Single lens Data lens (surface) Focal length
1 (1- 2) 5.011
2 (4-5) -8.086
3 (6-7) 4.273
4 (8-9) 88.730
5 (10-11) -3.667

Example 4
Unit: mm
Surface data surface number rd nd vd
Object ∞ ∞
1 * 2.390 0.573 1.58913 61.24
2 * 10.342 0.111
3 (Aperture) ∞ 0.419
4 * -3.596 0.350 1.63200 23.41
5 * -90.652 0.168
6 * 5.723 1.121 1.54470 56.15
7 * -2.394 0.225
8 * -7.314 0.350 1.54470 56.15
9 * -20.773 0.989
10 * -182.941 0.594 1.54470 56.15
11 * 2.212 0.455
12 ∞ 0.145 1.51600 64.10
13 ∞ 0.500
Image plane ∞

Aspheric data 1st surface
K = -1.6583e-001
A4 = -1.2354e-002
A6 = 4.0647e-003
A8 = -2.2437e-002
A10 = 1.7601e-002
A12 = -7.7411e-003
A14 = 3.6597e-004
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Second side
K = -1.7509e + 002
A4 = -1.6612e-002
A6 = -5.5272e-003
A8 = -4.1575e-002
A10 = 7.0975e-002
A12 = -5.1848e-002
A14 = 1.2052e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

4th page
K = -6.1990e-001
A4 = -7.3330e-002
A6 = 1.1810e-001
A8 = -1.0353e-001
A10 = 7.8019e-002
A12 = 4.2576e-003
A14 = -3.5769e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

5th page
K = -1.3413e + 005
A4 = -1.3345e-001
A6 = 2.4314e-001
A8 = -2.4266e-001
A10 = 2.1440e-001
A12 = -1.0446e-001
A14 = 1.9025e-002
A16 = -2.4711e-003
A18 = -1.1485e-004
A20 = 1.0619e-003

6th page
K = -1.0127e + 002
A4 = -5.0082e-002
A6 = 2.5510e-002
A8 = -1.1053e-002
A10 = 4.2073e-003
A12 = -9.0852e-004
A14 = 5.0997e-005
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

7th page
K = 3.1199e-001
A4 = -1.1833e-002
A6 = -5.5171e-003
A8 = 6.9646e-005
A10 = -1.2471e-004
A12 = -3.9151e-005
A14 = -2.2963e-005
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

8th page
K = 1.0331e + 001
A4 = -5.8353e-003
A6 = 2.0929e-003
A8 = -6.3810e-004
A10 = -2.0360e-004
A12 = -4.7244e-006
A14 = 1.9909e-005
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

9th page
K = 0.0000e + 000
A4 = -4.7866e-003
A6 = 4.7188e-003
A8 = -9.5919e-004
A10 = -1.0417e-004
A12 = 2.7089e-005
A14 = -5.4312e-008
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

10th page
K = -2.0074e + 043
A4 = -1.3344e-001
A6 = 2.6615e-002
A8 = -2.1640e-003
A10 = -2.2545e-004
A12 = 1.0975e-004
A14 = -9.5325e-006
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

11th page
K = -9.7793e + 000
A4 = -4.4594e-002
A6 = 8.3813e-003
A8 = -1.1820e-003
A10 = 9.5282e-005
A12 = -4.6883e-006
A14 = 1.8014e-007
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Various data
f 4.886
Fno. 2.884
ω 37.186
y'max 3.528
TL 5.950
BF 1.051

Single lens Data lens (surface) Focal length
1 (1-2) 5.138
2 (4-5) -5.935
3 (6-7) 3.258
4 (8-9) -20.917
5 (10-11) -4.008

Example 5
Unit: mm
Surface data surface number rd nd vd
Object ∞ ∞
1 * 3.007 0.530 1.58913 61.24
2 * 46.625 0.056
3 (Aperture) ∞ 0.409
4 * -3.854 0.350 1.63200 23.41
5 * -40.008 0.202
6 * 9.604 0.894 1.54470 56.15
7 * -2.982 0.050
8 * 3.229 0.350 1.54470 56.15
9 * 2.683 1.558
10 * 5.253 0.502 1.54470 56.15
11 * 1.854 0.455
12 ∞ 0.145 1.51600 64.10
13 ∞ 0.501
Image plane ∞

Aspheric data 1st surface
K = -1.3698e + 000
A4 = -1.9500e-002
A6 = -7.0710e-003
A8 = -1.6694e-002
A10 = 1.6857e-002
A12 = -1.3627e-002
A14 = 3.4814e-003
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Second side
K = -1.8232e + 020
A4 = -5.1239e-002
A6 = 6.0417e-003
A8 = -3.6888e-002
A10 = 5.5884e-002
A12 = -4.7345e-002
A14 = 1.6035e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

4th page
K = -1.0131e + 001
A4 = -9.7887e-002
A6 = 1.4378e-001
A8 = -1.2554e-001
A10 = 7.5888e-002
A12 = -1.2311e-002
A14 = -1.0286e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

5th page
K = -2.2050e + 014
A4 = -1.1355e-001
A6 = 2.1582e-001
A8 = -2.2081e-001
A10 = 1.8403e-001
A12 = -9.7706e-002
A14 = 2.0400e-002
A16 = -1.0392e-003
A18 = 4.1902e-003
A20 = -1.9677e-003

6th page
K = -2.4326e + 002
A4 = -4.5585e-002
A6 = 4.5856e-002
A8 = -2.0291e-002
A10 = 2.7470e-005
A12 = 1.0290e-003
A14 = 4.1013e-005
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

7th page
K = -4.0388e-001
A4 = -2.1399e-002
A6 = -3.7495e-003
A8 = 2.0322e-003
A10 = -9.3378e-004
A12 = -1.3551e-003
A14 = 3.7448e-004
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

8th page
K = 0.0000e + 000
A4 = -4.8182e-002
A6 = -3.2549e-003
A8 = -1.3113e-003
A10 = -1.0427e-003
A12 = 3.8315e-004
A14 = -1.7958e-004
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

9th page
K = 0.0000e + 000
A4 = -3.7848e-002
A6 = -1.4341e-003
A8 = -9.7338e-004
A10 = 1.7286e-004
A12 = 2.0672e-005
A14 = -5.1336e-006
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

10th page
K = 0.0000e + 000
A4 = -1.4692e-001
A6 = 2.8947e-002
A8 = -3.0495e-003
A10 = -1.6392e-004
A12 = 5.9491e-005
A14 = -4.2090e-006
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

11th page
K = -5.4210e + 000
A4 = -6.8083e-002
A6 = 1.6401e-002
A8 = -2.8457e-003
A10 = 2.2026e-004
A12 = -2.5982e-006
A14 = -5.8669e-007
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Various data
f 4.889
Fno. 2.884
ω 37.170
y'max 3.528
TL 5.952
BF 1.052

Single lens Data lens (surface) Focal length
1 (1-2) 5.432
2 (4-5) -6.773
3 (6-7) 4.285
4 (8-9) -37.721
5 (10- 11) -5.550

Example 6
Unit: mm
Surface data surface number rd nd vd
Object ∞ ∞
1 * (Aperture) 1.985 0.765 1.49700 81.61
2 * -24.139 0.410
3 * -2.795 0.345 1.54470 56.15
4 * -2.449 0.206
5 * -2.114 0.803 1.54470 56.15
6 * -1.456 0.222
7 * -1.417 0.852 1.63200 23.41
8 * -2.421 0.100
9 * 1.925 0.803 1.54470 56.15
10 * 1.320 0.850
11 ∞ 0.145 1.51600 64.10
12 ∞ 0.500
Image plane ∞

Aspheric data 1st surface
K = 9.7294e-002
A4 = -1.2760e-002
A6 = -1.2204e-002
A8 = -1.6351e-002
A10 = 1.3671e-002
A12 = -3.4824e-002
A14 = 7.2476e-003
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Second side
K = -1.8309e + 012
A4 = -6.5427e-002
A6 = -6.1534e-002
A8 = 4.8560e-002
A10 = -1.7209e-001
A12 = 1.7716e-001
A14 = -6.8797e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Third side
K = 4.5744e + 000
A4 = -9.0341e-002
A6 = 7.8789e-003
A8 = -9.0156e-002
A10 = 1.1693e-001
A12 = 4.0010e-002
A14 = -4.4739e-002
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

4th page
K = -1.9239e + 001
A4 = -1.7131e-001
A6 = 2.3739e-001
A8 = -2.7215e-001
A10 = 2.6324e-001
A12 = -1.3486e-001
A14 = 6.4334e-002
A16 = -2.9901e-002
A18 = 3.8837e-003
A20 = 9.8853e-004

5th page
K = -6.9373e + 000
A4 = -5.8560e-002
A6 = 6.5818e-002
A8 = -3.2290e-002
A10 = -8.5486e-004
A12 = 2.7642e-003
A14 = 2.6107e-004
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

6th page
K = 0.0000e + 000
A4 = -8.0915e-003
A6 = 4.5729e-002
A8 = -4.2865e-003
A10 = -1.8574e-003
A12 = 0.0000e + 000
A14 = 0.0000e + 000
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

7th page
K = 0.0000e + 000
A4 = 2.2979e-002
A6 = 2.1672e-002
A8 = -4.5419e-003
A10 = 1.2271e-003
A12 = 0.0000e + 000
A14 = 0.0000e + 000
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

8th page
K = 0.0000e + 000
A4 = 1.5555e-002
A6 = -5.2163e-003
A8 = 1.2748e-003
A10 = 9.1014e-005
A12 = -4.9836e-005
A14 = 5.1880e-006
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

9th page
K = -2.5315e + 000
A4 = -5.5925e-002
A6 = 6.9446e-003
A8 = -1.5155e-004
A10 = -2.8802e-005
A12 = 2.2586e-006
A14 = -5.0168e-008
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

10th page
K = -2.6745e + 000
A4 = -3.4534e-002
A6 = 5.9134e-003
A8 = -6.3140e-004
A10 = 3.7957e-005
A12 = -1.0647e-006
A14 = 8.9586e-009
A16 = 0.0000e + 000
A18 = 0.0000e + 000
A20 = 0.0000e + 000

Various data
f 4.111
Fno. 2.883
ω 37.782
y'max 3.528
TL 5.670
BF 1.165

Single lens Data lens (surface) Focal length
1 (1-2) 3.727
2 (3-4) 26.854
3 (5- 6) 6.004
4 (7-8) -8.060
5 (9-10) -14.499

DU Digital equipment LU Image pickup optical device LN Image pickup lens L1 to L5 First to fifth lenses ST Aperture stop (stop)
SR Image sensor SS Light-receiving surface IM Image surface (optical image)
AX Optical axis 1 Signal processing unit 1a Image processing unit 2 Control unit 3 Memory 4 Operation unit 5 Display unit

Claims (22)

In order from the object side, a first lens having a positive refractive power and a convex surface facing the object side, a second lens having a concave surface facing the object side, a third lens having a positive refractive power, and positive or negative A fourth lens having a refractive power of 5 and a fifth lens having a positive or negative refractive power, each of the first lens and the third lens having at least one aspheric surface, An imaging lens characterized by satisfying conditional expression (1);
0.4 <f3 / f1 <1.9 (1)
However,
f1: focal length of the first lens,
f3: focal length of the third lens
It is. The imaging lens according to claim 1, wherein the second lens has negative refractive power and satisfies the following conditional expression (2):
0.3 <r2a / f2 <0.8 (2)
However,
r2a: radius of curvature of the object side of the second lens,
f2: focal length of the second lens,
It is. The imaging lens according to claim 1, wherein the following conditional expression (3) is satisfied:
0.05 <T12 / TL <0.20 (3)
However,
T12: distance on the optical axis between the first lens and the second lens,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is. The imaging lens according to claim 1, wherein the following conditional expression (4) is satisfied:
0.7 <f1 / f <1.5 (4)
However,
f: focal length of the entire system,
f1: focal length of the first lens,
It is. The imaging lens according to claim 1, wherein the following conditional expression (5) is satisfied:
0.5 <f3 / f <1.6 (5)
However,
f: focal length of the entire system,
f3: focal length of the third lens
It is.   The imaging lens according to claim 1, further comprising an aperture stop between the first lens and the second lens. The imaging lens according to claim 1, wherein the first lens satisfies the following conditional expression (6):
60 <v1 <100 (6)
However,
v1: Abbe number of the first lens,
It is. The imaging lens according to claim 1, wherein the second lens satisfies the following conditional expressions (7) and (8):
1.6 <N2 <2.1 (7)
15 <v2 <30 (8)
However,
N2: refractive index of the second lens with respect to d-line,
v2: Abbe number of the second lens,
It is. The imaging lens according to any one of claims 1 to 8, wherein the second lens satisfies the following conditional expression (9):
-0.08 <T2 / f2 <-0.02 (9)
However,
T2: thickness on the optical axis of the second lens,
f2: focal length of the second lens,
It is.   The imaging lens according to claim 1, wherein a part of the first to fifth lenses is extended during focusing from infinity to the closest distance. The imaging lens according to claim 10, wherein the first lens to the fourth lens are integrally extended to satisfy the following conditional expression (10):
0.1 <T45 / TL <0.3 (10)
However,
T45: distance on the optical axis between the fourth lens and the fifth lens,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.   The first lens has an object-side convex meniscus shape, the second lens has an image-side convex meniscus shape or biconcave shape, and the third lens has a biconvex shape or image-side convex meniscus shape. The fourth lens has at least one aspheric surface and has a weak refractive power, and the fifth lens has at least one aspheric surface and has a convex meniscus shape or biconcave shape on the object side. The imaging lens according to claim 1, wherein the imaging lens is characterized in that   The surface shape of at least one surface of the fifth lens is an aspheric shape having an inflection point at a position other than the intersection with the optical axis. Imaging lens.   14. The imaging according to claim 1, wherein the surface shape of the image side surface of the second lens is an aspherical shape having an inflection point at a position other than an intersection with the optical axis. lens.   The surface shape of at least one surface of the fourth lens is an aspherical shape having an inflection point at a position other than the intersection with the optical axis. Imaging lens. The imaging lens according to claim 1, wherein the following conditional expression (11) is satisfied:
0.4 <Y '/ TL <0.8 (11)
However,
Y ': Maximum image height,
TL: Distance on the optical axis from the surface vertex of the lens surface closest to the object side to the image plane (however, the back focus is the air equivalent length),
It is.   An imaging lens according to any one of claims 1 to 16, and an imaging device that converts an optical image formed on the light receiving surface into an electrical signal, and a subject on the light receiving surface of the imaging device. An imaging optical apparatus, wherein the imaging lens is provided so that an optical image of the above is formed.   18. A digital device comprising the imaging optical device according to claim 17, to which at least one function of still image shooting and moving image shooting of a subject is added.   19. The digital apparatus according to claim 18, further comprising an image processing unit that electrically processes image data obtained from the imaging optical device.   The digital device according to claim 19, wherein the image processing unit corrects image distortion.   The digital apparatus according to claim 19, wherein the depth of focus is expanded by the image processing unit.   The digital device according to any one of claims 18 to 21, wherein the digital device is a portable terminal.

Images