JP2014240978A - Imaging lens and imaging apparatus including imaging lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging lens capable of obtaining high resolution performance, an imaging apparatus, and portable terminal equipment.SOLUTION: The imaging lens comprises, in order from an object side, a first lens G1 whose object-side surface has a convex shape on the object side near an optical axis and which has positive refractive power, a second lens G2 which has negative refractive power, a third lens G3 which has positive refractive power, a fourth lens G4 whose image-side surface has a convex shape on an image side near the optical axis and which has refractive power, and a fifth lens G5 whose object-side surface has a convex shape on the object side near the optical axis, image-side surface has a concave shape on the image side near the optical axis and peripheral part has a convex shape and which has refractive power, and satisfies conditional expressions given below: (1):D7>D6, (2):0.8<f/f1<1.5, (4A):νd2<25, (5A):f4<f1, (5B):f4<|f2|, (5C):f4<f3.

Description

  The present invention relates to an imaging lens that forms an optical image of a subject on an imaging device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and a digital still camera that performs imaging by mounting the imaging lens. And a portable terminal device such as a mobile phone with a camera and a portable information terminal (PDA: Personal Digital Assistance).

  In recent years, with the spread of personal computers to ordinary homes and the like, digital still cameras that can input image information such as photographed landscapes and human images to personal computers are rapidly spreading. In addition, camera modules for image input are often mounted on mobile phones. An image sensor such as a CCD or a CMOS is used for a device having such an image capturing function. In recent years, these image pickup devices have been made more compact, and the entire image pickup apparatus and the image pickup lens mounted thereon are also required to be compact. At the same time, the number of pixels of the image sensor is increasing, and there is a demand for higher resolution and higher performance of the imaging lens. In order to satisfy such a demand, an imaging lens having a configuration using four lenses as a whole has been developed in the past, but recently, in order to achieve higher resolution and higher performance, the number of lenses has been increased. It tends to increase.

Japanese Patent No. 3788133 JP 2007-264180 A JP 2007-279282 A

  Patent Documents 1 to 3 disclose imaging lenses that have five lenses to improve performance, but in recent years, higher resolution performance is required than the imaging lenses described in these documents. .

  The present invention has been made in view of such problems, and an object of the present invention is to provide an imaging lens and an imaging apparatus, and a portable terminal device that can obtain high resolution performance.

  The imaging lens according to the present invention includes, in order from the object side, a first lens having a positive refractive power and a second lens having a negative refractive power, the object side surface being convex toward the object side in the vicinity of the optical axis. The third lens having a positive refractive power, the image side surface is convex on the image side in the vicinity of the optical axis, and the fourth lens having a refractive power and the object side surface on the object side in the vicinity of the optical axis. It has a convex shape, and the image side surface is concave on the image side in the vicinity of the optical axis, and has a refractive power and a fifth lens having a refractive power. This imaging lens further includes the following conditional expressions (1): D7> D6, (2): 0.8 <f / f1 <1.5, (4A): νd2 <25, (5A): f4 <f1, (5B): f4 <| f2 |, (5C): f4 <f3 is satisfied. Where D6 is the thickness on the optical axis of the third lens, D7 is the air spacing on the optical axis of the third lens and the fourth lens, f is the focal length of the entire system, f1 is the focal length of the first lens, and f2 Is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and νd2 is the Abbe number for the d-line of the second lens.

The imaging lens according to the present invention has a five-lens configuration as a whole, and the number of lenses is increased as compared with the conventional four-lens imaging lens, and the configuration of each lens is optimized to increase the number of pixels. A corresponding high resolution lens system can be obtained.
Further, by adopting and satisfying the following preferable configuration as appropriate, it becomes easier to achieve higher performance.

  The imaging lens according to the present invention preferably satisfies the following conditional expression in order to obtain higher resolution performance.

f1 <| f2 | <f3 (3)
Here, f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

  In the imaging lens according to the present invention, it is preferable that both the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are aspheric on both surfaces. Note that the object-side surface of the fifth lens may have an aspheric shape having an inflection point within the effective diameter. Further, the image-side surface of the fifth lens can have an aspherical shape having an inflection point within the effective diameter. In addition, the image-side surface of the fifth lens can have an aspherical shape having a pole other than the center of the optical axis within the effective diameter.

  An imaging apparatus according to the present invention includes an imaging lens according to the present invention and an imaging element that outputs an imaging signal corresponding to an optical image formed by the imaging lens. Note that the imaging element may have a pixel count of 2 megapixels or more and a pixel pitch of 3 μm or less.

  A portable terminal device according to the present invention includes the imaging device according to the present invention and display means for displaying an image captured by the imaging device.

  In the imaging apparatus or the portable terminal device according to the present invention, a high-resolution imaging signal is obtained based on the high-resolution optical image obtained by the imaging lens of the present invention.

  According to the imaging lens of the present invention, since the shape of each lens is appropriately optimized in a lens configuration of five as a whole, high resolution performance can be obtained.

  In addition, according to the imaging device or the portable terminal device of the present invention, since the imaging signal corresponding to the optical image formed by the imaging lens having the high resolution performance of the present invention is output, the high resolution shooting is performed. An image can be obtained.

6 is a cross-sectional view of an imaging lens corresponding to Configuration Example 1. FIG. 6 is a cross-sectional view of an imaging lens corresponding to Configuration Example 2. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 3. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 4. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 5. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 6. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 7. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 8. FIG. 10 is a cross-sectional view of an imaging lens corresponding to Configuration Example 9. FIG. 14 is a cross-sectional view of an imaging lens corresponding to Configuration Example 10. FIG. 14 is a cross-sectional view of an imaging lens corresponding to Configuration Example 11. FIG. 14 is a cross-sectional view of an imaging lens corresponding to Configuration Example 12. FIG. 14 is a cross-sectional view of an imaging lens corresponding to Configuration Example 13. FIG. 16 is a cross-sectional view of an imaging lens corresponding to Configuration Example 14. FIG. 16 is a cross-sectional view of an imaging lens corresponding to Configuration Example 15. FIG. 16 is a cross-sectional view of an imaging lens corresponding to Configuration Example 16. FIG. 16 is a cross-sectional view of an imaging lens corresponding to Configuration Example 17. FIG. 22 is a cross-sectional view of an imaging lens corresponding to Configuration Example 18. FIG. 22 is a cross-sectional view of an imaging lens corresponding to Configuration Example 19. FIG. 22 is a cross-sectional view of an imaging lens corresponding to Configuration Example 20. FIG. 22 is a cross-sectional view of an imaging lens corresponding to Configuration Example 21. FIG. It is an aberration diagram which shows the various aberrations concerning the imaging lens of the structural example 1, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations concerning the imaging lens of the structural example 2, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations concerning the imaging lens of the structural example 3, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations concerning the imaging lens of the structural example 4, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 5, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 6, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 7, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 8, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 9, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 10, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 11, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 12, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 13, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations concerning the imaging lens of the structural example 14, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 15, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 16, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 17, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 18, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations regarding the imaging lens of the structural example 19, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 20, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an aberration diagram which shows the various aberrations which concern on the imaging lens of the structural example 21, (A) shows spherical aberration, (B) shows astigmatism, and (C) shows distortion. It is an external view which shows the example of 1 structure of the mobile phone with a camera as a portable terminal device. It is a perspective view which shows one structural example of the camera module as an imaging device.

  Hereinafter, embodiments of an imaging lens, an imaging device, and a mobile terminal device will be described in detail with reference to the drawings. Of the imaging lenses of the embodiments, the imaging lenses of Configuration Examples 1, 2, 5, 8, and 13 belong to the present invention, and Configuration Examples 3, 4, 6, 7, 9 to 12, and 14 to The image pickup lens 21 does not belong to the present invention. The imaging apparatus according to the embodiment includes the imaging lens according to the above-described embodiment and an imaging element that outputs an imaging signal corresponding to an optical image formed by the imaging lens. Here, the imaging devices including the imaging lenses of the configuration examples 1, 2, 5, 8, and 13 belong to the present invention, and the imaging lenses of the configuration examples 3, 4, 6, 7, 9 to 12, and 14 to 21 are included. The imaging device provided with is not included in the present invention. Furthermore, the portable terminal device of the embodiment includes the imaging device and display means for displaying an image captured by the imaging device. Here, the portable terminal device provided with the imaging lenses of the configuration examples 1, 2, 5, 8, and 13 belongs to the present invention, and the configuration examples 3, 4, 6, 7, 9 to 12, and 14 to 21 are included. The portable terminal device provided with the imaging lens does not belong to the present invention.

FIG. 1 shows a cross section of the imaging lens of Configuration Example 1. Table 1 shows basic lens data that is numerical data related to the imaging lens of Structural Example 1, and Table 2 shows aspherical data that is numerical data related to the lens surfaces constituting the imaging lens of Structural Example 1. ing. The basic lens data and aspherical data are collectively referred to as lens data.
Similarly, FIGS. 2 to 21 illustrate cross sections of the imaging lenses of Configuration Examples 2 to 21. FIG. Each of Tables 3, 5, 7... 41 (table indicated by odd numbers) represents basic lens data relating to each imaging lens of Configuration Examples 2 to 21, and Tables 4, 6, 8... 42 (even numbers). Each table shows aspherical data relating to lens surfaces constituting each imaging lens of Configuration Examples 2 to 21.

  In FIGS. 1 to 21 showing the cross section of the imaging lens, the reference symbol Ri increases sequentially toward the image side (imaging side), with the surface of the most object side component including the stop St as the first. The radius of curvature of the i-th surface labeled with The symbol Di indicates the surface interval on the optical axis Z1 between the i-th surface and the i + 1-th surface. Since the basic configuration is the same for each configuration example, the following description is based on the first configuration example shown in FIG.

  FIGS. 43A and 43B show a camera-equipped mobile phone as an example of the mobile terminal device according to the present embodiment. FIG. 44 shows an example of the configuration of a camera module as an imaging apparatus according to this embodiment. The camera-equipped mobile phone shown in FIGS. 43A and 43B includes an upper housing 2A and a lower housing 2B, both of which are configured to be rotatable in the direction of the arrow in FIG. . The lower housing 2B is provided with operation keys 21 and the like. The upper housing 2A is provided with a camera unit 1 (FIG. 43B), a display unit (display means) 22 (FIG. 43A), and the like. The display unit 22 includes a display panel such as an LCD (liquid crystal panel) or an EL (Electro-Luminescence) panel. The display part 22 is arrange | positioned at the side used as an inner surface at the time of folding. The display unit 22 can display various menus related to the telephone function and images taken by the camera unit 1. The camera unit 1 is disposed, for example, on the back side of the upper housing 2A. However, the position where the camera unit 1 is provided is not limited to this.

  The camera unit 1 has a camera module as shown in FIG. 44, for example. As shown in FIG. 44, the camera module corresponds to the lens barrel 3 in which the imaging lens 20 is accommodated, the support substrate 4 that supports the lens barrel 3, and the imaging surface of the imaging lens 20 on the support substrate 4. And an image sensor (not shown) provided at a position to be operated. The camera module is also configured to be connected to a flexible substrate 5 electrically connected to the image pickup device on the support substrate 4 and to a signal processing circuit on the telephone body side while being electrically connected to the flexible substrate 5. And an external connection terminal 6. These components are integrally configured.

  In the camera unit 1, the optical image formed by the imaging lens 20 is converted into an electrical imaging signal by the imaging device, and the imaging signal is output to a signal processing circuit on the device body side. By using the imaging lens according to the present embodiment as the imaging lens 20 in such a camera-equipped mobile phone, a high-resolution imaging signal with sufficient aberration correction can be obtained. On the telephone body side, a high-resolution image can be generated based on the imaging signal.

  Note that the imaging lens according to the present embodiment can be applied to various imaging devices or portable terminal devices using imaging elements such as a CCD and a CMOS. The imaging device or portable terminal device according to the present embodiment is not limited to a camera-equipped mobile phone, and may be, for example, a digital still camera or a PDA. In addition, the imaging lens according to the present embodiment is particularly suitable for an imaging apparatus or a portable terminal device having a small, high-pixel imaging device having a pixel number of 2 megapixels or more and a pixel pitch of 3 μm or less. Can do.

  This imaging lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, and a fifth lens G5 in order from the object side along the optical axis Z1. The optical aperture stop St can be disposed on the front side of the first lens G1, more specifically, on the object side of the image side surface of the first lens G1 on the optical axis Z1, for example. Further, as in the configuration examples of FIGS. 9 to 14, it is also possible to arrange an aperture stop St between the image side surface of the first lens G1 and the object side surface of the second lens G2.

  An imaging element such as a CCD is disposed on the imaging surface Simg of the imaging lens. Various optical members GC may be disposed between the fifth lens G5 and the image sensor in accordance with the configuration on the camera side where the lens is mounted. For example, a flat optical member such as a cover glass for protecting the imaging surface or an infrared cut filter may be disposed. In this case, as the optical member GC, for example, a flat cover glass provided with a coating having a filter effect such as an infrared cut filter or an ND filter may be used. In this imaging lens, all of the first lens G1 to the fifth lens G5 or at least one lens surface is coated with a filter effect coating such as an infrared cut filter or an ND filter, or an antireflection coating. Also good.

  The first lens G1 has a positive refractive power. The first lens G1 is a positive lens having a lens surface on the object side convex toward the object side in the vicinity of the optical axis. For example, the first lens G1 may have a biconvex shape in the vicinity of the optical axis or a meniscus shape convex toward the object side.

  The second lens G2 has a negative refractive power. The second lens G2 can have a concave lens surface on the image side in the vicinity of the optical axis.

  The third lens G3 can be a positive lens having a concave lens surface on the image side in the vicinity of the optical axis, for example, a positive meniscus lens having a concave surface on the image side in the vicinity of the optical axis.

  The fourth lens G4 has refractive power, and the lens surface on the image side has a convex shape on the image side in the vicinity of the optical axis.

  The fifth lens G5 has a refractive power, and the lens surface on the image side has a concave shape on the image side in the vicinity of the optical axis. The fifth lens can have a meniscus shape (for example, Configuration Example 1 shown in FIG. 1) in the vicinity of the optical axis.

This imaging lens is configured to satisfy the following conditional expressions (1), (2), (4A), (5A), (5B), and (5C).
D7> D (1)
0.8 <f / f1 <1.5 (2)
νd2 <25 (4A)
f4 <f1 (5A)
f4 <| f2 | (5B)
f4 <f3 (5C)
However, D6 is the thickness on the optical axis of the third lens, D7 is the air space on the optical axis between the third lens and the fourth lens, f is the focal length of the entire system, f1 is the focal length of the first lens, f2 Is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and νd2 is the Abbe number for the d-line of the second lens.

This imaging lens preferably satisfies the following conditional expression (3).
f1 <| f2 | <f3 (3)
In this imaging lens, it is preferable that both the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, and the fifth lens G5 are aspheric on both surfaces. In particular, it is preferable that the fourth lens G4 and the fifth lens G5 have an aspherical shape in which the vicinity of the optical axis and the peripheral portion have different uneven shapes.

  For example, the image-side surface of the fifth lens G5 is preferably concave in the vicinity of the optical axis, and has a region in which the negative refractive power becomes weaker as compared to the vicinity of the optical axis. The image-side surface of the fifth lens G5 is preferably an aspherical shape having an inflection point within the effective diameter. The image-side surface of the fifth lens G5 is preferably an aspherical shape having a pole other than the center of the optical axis within the effective diameter. Specifically, for example, the image-side surface of the fifth lens G5 is preferably an aspherical surface having a concave shape in the vicinity of the optical axis and a convex shape in the peripheral portion. Furthermore, it is preferable that the object side surface of the fifth lens G5 has an aspherical shape having an inflection point within the effective diameter.

In general, the aspherical expression is represented by the following expression (A).
Z = C · h ² / {1+ (1−K ′ · C ² · h ² ) ^1/2 } + ΣA _i · h ⁱ (A)
However,
K '= 1 + K
K: Eccentricity Z: Depth of aspheric surface (mm)
h: Distance from the optical axis to the lens surface (height) (mm)
C: Paraxial curvature = 1 / R
(R: paraxial radius of curvature)
ΣA _i · h ⁱ : Sum of A _i · h ⁱ when i = 1 to n (n = an integer of 3 or more)
A _i : i-th aspheric coefficient Z is a perpendicular line drawn from a point on the aspheric surface at a height h from the optical axis to the tangent plane (plane perpendicular to the optical axis) of the apex of the aspheric surface. Length (mm) is shown. That is, Z indicates the sag amount (depth) of the aspheric surface with reference to the surface vertex position at the height h from the optical axis.

[Action / Effect]
Next, operations and effects of the imaging lens configured as described above will be described.
This imaging lens has a five-lens configuration as a whole, increases the number of lenses compared to the conventional four-lens imaging lens, and optimizes the configuration of each lens, so that it can cope with higher pixels. A lens system with high resolution performance can be obtained.

  In addition, it is easy to obtain high resolution performance by satisfying conditional expression (1) and by relatively widening the distance between the third lens G3 and the fourth lens G4. If the conditional expression (1) is not satisfied and the distance between the third lens G3 and the fourth lens G4 becomes relatively narrow, the curvature of field becomes large, and high resolution performance cannot be obtained.

Conditional expression (2) relates to the refractive power of the first lens G1. In this imaging lens, an optical system with a short overall length can be obtained by occupying the main imaging function of the first lens G1 so as to satisfy the conditional expression (2). If the lower limit of conditional expression (2) is not reached, the total length becomes long. Exceeding the upper limit is advantageous for shortening the overall length, but the field curvature becomes large, and high resolution performance cannot be obtained.
In order to obtain a higher resolution performance with a shorter overall length, the numerical range of conditional expression (2) is preferably the numerical range of conditional expression (2A) below.
1.0 <f / f1 <1.4 (2A)
More preferably, it is in the numerical range of the following conditional expression (2B).
1.1 <f / f1 <1.35 (2B)
More preferably, it is in the numerical range of the following conditional expression (2C).
1.12 <f / f1 <1.35 (2C)
Conditional expression (3) shows an appropriate relationship among the focal lengths of the first lens G1, the second lens G2, and the third lens G3. Conditional expression (4A) relates to an appropriate Abbe number of the second lens G2. Satisfying conditional expression (3) and conditional expression (4A) is advantageous for chromatic aberration correction. In particular, if the upper limit of conditional expression (4A) is exceeded, chromatic aberration correction will be insufficient.

Conditional expressions (5A), (5B), and (5C) show an appropriate relationship between the focal lengths of the first lens G1, the second lens G2, and the third lens G3 with respect to the focal length of the fourth lens G4. . When the conditional expressions (5A), (5B), and (5C) are satisfied, the F-number is reduced and a bright lens system can be easily realized.
In order to obtain brighter and higher resolution performance, the focal lengths of the first lens G1, the second lens G2, the third lens G3, and the fourth lens G4 may have the following conditional expression (5D). preferable.
f4 <f1 <| f2 | <f3 (5D)
In this imaging lens, the aspherical shape of the fourth lens G4 and the fifth lens G5 arranged on the image side with respect to the other lenses is different from that of the uneven shape in the vicinity of the optical axis and in the peripheral portion. By doing so, it is possible to satisfactorily correct the curvature of field from the center to the periphery of the image plane. In particular, the image-side surface of the fifth lens G5 has a region in which the negative refractive power becomes weaker as it goes toward the periphery, so that the curvature of field can be corrected well and high resolution can be achieved. Image performance is obtained.

As described above, according to the imaging lens according to the present embodiment, in the lens configuration of five as a whole, the shape of each lens is appropriately set and the predetermined conditional expression is satisfied. High resolution performance can be obtained. Further, according to the imaging device or the mobile terminal device according to the present embodiment, since the imaging signal corresponding to the optical image formed by the imaging lens with high resolution performance according to the present embodiment is output, A high-resolution captured image can be obtained.
<Configuration example>
Next, lens data related to the imaging lens of the present embodiment will be described. The lens data relating to the imaging lenses of the configuration examples 1, 2, 5, 8, and 13 belong to the present invention, and the imaging lenses of the configuration examples 3, 4, 6, 7, 9 to 12, and 14 to 21 are included. Such lens data does not belong to the present invention.

[Configuration example 1]
[Table 1] and [Table 2] show lens data corresponding to the imaging lens of the configuration example 1 shown in FIG. In particular, [Table 1] shows basic lens data as basic lens data, and [Table 2] shows aspherical data. In the field of the surface number Si in the basic lens data shown in [Table 1], for the imaging lens according to Configuration Example 1, the surface of the component closest to the object side is the first, and increases sequentially toward the image side. The number of the i-th surface (i = 1 to 13) with reference numerals is shown. In the column of the curvature radius Ri, the value (mm) of the curvature radius of the i-th surface from the object side is shown in correspondence with the reference symbol Ri in FIG. Similarly, the column of the surface interval Di indicates the interval (mm) on the optical axis between the i-th surface Si and the i + 1-th surface Si + 1 from the object side. In the columns of Ndi and νdj, the values of the refractive index and the Abbe number of the j-th optical element from the object side with respect to the d-line (587.6 nm) are shown.

  In the imaging lens according to Structural Example 1, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, and the fifth lens G5 are all aspherical on both surfaces. The basic lens data in [Table 1] shows numerical values of the radius of curvature near the optical axis as the radius of curvature of these aspheric surfaces.

[Table 2] shows aspherical data in the imaging lens according to Structural Example 1. In the numerical values shown as aspherical data, the symbol “E” indicates that the subsequent numerical value is a “power exponent” with a base of 10, and the numerical value represented by an exponential function with the base of 10 is Indicates that the value before “E” is multiplied. For example, “1.0E-02” indicates “1.0 × 10 ⁻² ”.

  As the aspheric surface data of the imaging lens according to Configuration Example 1, the values of the coefficients Ai and K in the aspheric surface expression represented by the above-described aspheric expression (A) are described. The imaging lens according to Configuration Example 1 is represented by effectively using coefficients up to the 10th order as the aspheric coefficient Ai. Although omitted in the table, the primary and secondary aspherical coefficients A1 and A2 are set to 0 (that is, A1 = 0, A2 = 0).

[Configuration Examples 2 to 21]
Similarly to the above configuration example 1, lens data corresponding to the imaging lens of the configuration example 2 shown in FIG. 2 are shown in [Table 3] and [Table 4]. Similarly, lens data corresponding to the imaging lenses of configuration examples 3 to 21 shown in FIGS. 3 to 21 are shown in [Table 5], [Table 6] to [Table 41], and [Table 42].

  In any imaging lens of Configuration Examples 2 to 21, as in the imaging lens of Configuration Example 1, all lens surfaces are aspherical.

[Other numerical data for each configuration example]
[Table 43] showing other numerical data of each configuration example is related to the above-described conditional expressions (1), (2), (3), (4A), (5A), (5B), and (5C). The values to be summarized for each configuration example are shown. As can be seen from [Table 43], the imaging lenses of Configuration Examples 1, 2, 5, 8, and 13 belonging to the present invention are conditional expressions (1), (2), (4A), (5A), and (5B). , (5C) is satisfied. [Table 43] also shows the F number (FNO.) Value as various data.

[Aberration performance]
22A to 22C respectively show spherical aberration, astigmatism, and distortion (distortion aberration) in the imaging lens according to Configuration Example 1. FIG. In these aberration diagrams, the d-line is the reference wavelength, and aberrations for the C-line (wavelength 656.27 nm) and the F-line (wavelength 486.13 nm) are also shown. In the graph showing astigmatism, (S) shows the sagittal direction, and (T) shows the tangential aberration. ω indicates a half angle of view. In FIG. 22A, the vertical axis indicates the entrance pupil diameter (mm).

  Similarly, various aberrations of the imaging lenses according to Structural Examples 2 to 21 are shown in FIGS. 23 (A) to (C) to FIGS. 42 (A) to (C). In FIGS. 39B and 39C, the vertical axis indicates the image height Y (mm).

  As can be seen from the above numerical data and aberration diagrams, the imaging lenses of Configuration Examples 1, 2, 5, 8, and 13 belonging to the present invention are configured with five lenses as a whole and have high resolution performance. The system has been realized.

  The imaging lens of the present invention is not limited to the imaging lenses of the above configuration examples 1, 2, 5, 8, and 13, and various modifications can be made. For example, the values of the radius of curvature, the surface spacing, and the refractive index of each lens component are not limited to the values shown in the above numerical data, and may take other values.

  GC ... optical member, G1 ... first lens, G2 ... second lens, G3 ... third lens, G4 ... fourth lens, G5 ... fifth lens, St ... aperture stop, Ri ... i-th lens from the object side The radius of curvature of the surface, Di: the distance between the i-th lens surface and the i + 1-th lens surface from the object side, Z1,.

Claims (9)

From the object side,
A first lens whose surface on the object side is convex toward the object side in the vicinity of the optical axis and having a positive refractive power;
A second lens having negative refractive power;
A third lens having positive refractive power;
A fourth lens having an image side surface convex toward the image side in the vicinity of the optical axis and having a refractive power;
From the fifth lens having a refractive power, the object side surface is convex toward the object side in the vicinity of the optical axis, the image side surface is concave toward the image side near the optical axis, and is convex at the periphery. Become
Furthermore, the imaging lens characterized by satisfying the following conditional expressions (1), (2), (4A), (5A), (5B), and (5C).
D7> D6 (1)
0.8 <f / f1 <1.5 (2)
νd2 <25 (4A)
f4 <f1 (5A)
f4 <| f2 | (5B)
f4 <f3 (5C)
However,
D6: Thickness on the optical axis of the third lens D7: Air spacing on the optical axis between the third lens and the fourth lens f: Focal length of the entire system f1: Focal length of the first lens f2: Focal point of the second lens Distance f3: Focal length of the third lens f4: Focal length of the fourth lens νd2: Abbe number related to the d-line of the second lens. The imaging lens according to claim 1, further satisfying the following conditional expression:
f1 <| f2 | <f3 (3) The first lens, the second lens, the third lens, the fourth lens, and the fifth
The imaging lens according to claim 1, wherein all the lenses are aspheric on both sides. The imaging lens according to any one of claims 1 to 3, wherein the object side surface of the fifth lens has an aspherical shape having an inflection point within an effective diameter. 5. The imaging lens according to claim 1, wherein an image-side surface of the fifth lens has an aspheric shape having an inflection point within an effective diameter. 6. The imaging lens according to claim 1, wherein the image-side surface of the fifth lens has an aspherical shape having a pole other than the center of the optical axis within the effective diameter. The imaging lens according to any one of claims 1 to 6,
An imaging device comprising: an imaging element that outputs an imaging signal corresponding to an optical image formed by the imaging lens. The imaging device according to claim 7, wherein the imaging device has a number of pixels of 2 megapixels or more and a pixel pitch of 3 μm or less. An imaging device according to claim 7 or 8,
A portable terminal device comprising: display means for displaying an image picked up by the image pickup device.