JP2004109585A - Imaging lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging lens system for a solid-state imaging device which has satisfactory optical performance and is low-cost and compact. <P>SOLUTION: The imaging lens is constituted of two lenses for forming an image on the solid-state imaging device, namely, a first lens (L1) having a meniscus shape with a convex surface on the object side and having a positive optical power and a second lens (L2) having a meniscus shape with a concave surface on the image side and having a negative optical power, which are arranged in order from the object side, and a focal length f1 of the first lens (L1) and a focal length f2 of the second lens (L2) fulfill conditional expression ¾f2¾/f1<25. <P>COPYRIGHT: (C)2004,JPO

Description

【００３８】
［第２面（ｒ２）の非球面データ］
ε＝−０．４０８１８×１０，Ａ４＝０．３３７７９，Ａ６＝−０．１８５４８，Ａ８＝０．１２８９０，Ａ１０＝−０．９４４３８×１０^−２
［第３面（ｒ３）の非球面データ］
ε＝０．１００００×１０，Ａ４＝０．１２１７９×１０^−１，Ａ６＝０．３５０３０，Ａ８＝−０．６０５７２，Ａ１０＝０．７９６９１
［第４面（ｒ４）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．１２８５５，Ａ６＝−０．１５９７７，Ａ８＝０．２８０５３，Ａ１０＝−０．２３９４８
［第５面（ｒ５）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．７２８２０×１０^−１，Ａ６＝０．７８３０１×１０^−２，Ａ８＝−０．６９２６８×１０^−３，Ａ１０＝−０．８３００４×１０^−３
【００３９】

【００４０】
［第２面（ｒ２）の非球面データ］
ε＝−０．４６３２６×１０，Ａ４＝０．３３５１２，Ａ６＝−０．１９３７８，Ａ８＝０．１４２８０，Ａ１０＝−０．１８９５９×１０^−１
［第３面（ｒ３）の非球面データ］
ε＝０．１００００×１０，Ａ４＝０．４４７２８×１０^−１，Ａ６＝０．３０２９５，Ａ８＝−０．４８５０３，Ａ１０＝０．６３８０５
［第４面（ｒ４）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．９２３７７×１０^−１，Ａ６＝−０．７７５１１×１０^−１，Ａ８＝０．９７８９１×１０^−１，Ａ１０＝−０．５７０１１×１０^−１
［第５面（ｒ５）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．６１３３５×１０^−１，Ａ６＝−０．４８８７１×１０^−２，Ａ８＝０．４０６３７×１０^−２，Ａ１０＝−０．１３８２３×１０^−２
【００４１】

【００４２】
［第２面（ｒ２）の非球面データ］
ε＝−０．４６８５５×１０，Ａ４＝０．３２６５８，Ａ６＝−０．２００１２，Ａ８＝０．１７３４５，Ａ１０＝−０．４８５８７×１０^−１
［第３面（ｒ３）の非球面データ］
ε＝０．１００００×１０，Ａ４＝０．３６６９７×１０^−１，Ａ６＝０．２９６７４，Ａ８＝−０．４３５９０，Ａ１０＝０．５３７９２
［第４面（ｒ４）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．９５０６６×１０^−１，Ａ６＝−０．２６８６７×１０^−１，Ａ８＝０．３４９６４×１０^−１，Ａ１０＝−０．２１１８９×１０^−１
［第５面（ｒ５）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．５３４５４×１０^−１，Ａ６＝−０．６４５４１×１０^−２，Ａ８＝０．３７３７０×１０^−２，Ａ１０＝−０．１１３４０×１０^−２
【００４３】

【００４４】
［第２面（ｒ２）の非球面データ］
ε＝−０．７０２０２×１０，Ａ４＝０．９６１１２，Ａ６＝−０．１６６４３×１０，Ａ８＝０．２６５９８×１０，Ａ１０＝−０．１７４６８×１０
［第３面（ｒ３）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．１１４７６，Ａ６＝０．１９６４５×１０，Ａ８＝−０．５４０９１×１０，Ａ１０＝０．８５３６９×１０
［第４面（ｒ４）の非球面データ］
ε＝０．１００００×１０，Ａ４＝−０．２０４５９，Ａ６＝−０．１５７５５，Ａ８＝０．３９５３７，Ａ１０＝−０．２９２０９
［第５面（ｒ５）の非球面データ］
ε＝０．１００００×１０，Ａ４＝０．１０６２８×１０^−１，Ａ６＝−０．２３５３２，Ａ８＝０．１９５７７，Ａ１０＝−０．６７３７０×１０^−１
【００４５】
【表１】

【００４６】
【発明の効果】
以上説明したように本発明によれば、光学性能が良好で低コストかつコンパクトな固体撮像素子用の撮像レンズを実現することができる。そして、本発明に係る撮像レンズを携帯電話搭載のカメラやデジタルカメラ等のデジタル入力機器に用いれば、当該機器の高性能化，高機能化，低コスト化及びコンパクト化に寄与することができる。
【図面の簡単な説明】
【図１】第１の実施の形態（実施例１）のレンズ構成図。
【図２】第２の実施の形態（実施例２）のレンズ構成図。
【図３】第３の実施の形態（実施例３）のレンズ構成図。
【図４】第４の実施の形態（実施例４）のレンズ構成図。
【図５】実施例１の収差図。
【図６】実施例２の収差図。
【図７】実施例３の収差図。
【図８】実施例４の収差図。
【符号の説明】
ＳＴ　…開口絞り
Ｌ１　…第１レンズ
Ｌ２　…第２レンズ
ＧＦ　…ガラスフィルター
ＡＸ　…光軸[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an imaging lens, and more particularly, to a small-sized imaging lens suitable for a digital input device (digital still camera, digital video camera, or the like) that captures an image of a subject with a solid-state imaging device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the spread of personal computers and the like, digital still cameras, digital video cameras, and the like (hereinafter, simply referred to as “digital cameras”) that can easily capture image information into digital devices have become widespread at the individual user level. Such digital cameras are expected to be increasingly used as image information input devices in the future.
[0003]
In addition, miniaturization of solid-state imaging devices such as charge coupled devices (CCDs) mounted on digital cameras has been progressing, and accordingly, further miniaturization of digital cameras has been required. Therefore, there is a strong demand for a compact imaging lens which occupies the largest volume in a digital input device. In order to reduce the size of the imaging lens, it is easiest to reduce the size of the solid-state imaging device, but for that purpose, it is necessary to reduce the size of the light-receiving device, which increases the difficulty of manufacturing the solid-state imaging device. The performance required for the imaging lens also increases.
[0004]
On the other hand, if the size of the imaging lens is reduced while keeping the size of the solid-state imaging device, the exit pupil position necessarily approaches the image plane. When the position of the exit pupil approaches the image plane, the off-axis luminous flux emitted from the imaging lens is obliquely incident on the image plane, so that the condensing performance of the microlens provided on the front surface of the solid-state imaging device is sufficiently high. This causes a problem that the brightness of the image is extremely changed between the central portion of the image and the peripheral portion of the image. If the exit pupil position of the imaging lens is set far away in order to solve this problem, it is inevitable that the entire imaging lens becomes larger.
[0005]
Furthermore, due to the recent price competition, there has been an increasing demand for lower cost imaging lenses. In response to the above demands, an imaging lens having a two-lens configuration for a solid-state imaging device has been proposed in Patent Document 1 and the like.
[0006]
[Patent Document 1]
JP 2001-183578 A
[Problems to be solved by the invention]
However, most of those proposed in Patent Document 1 and the like have a configuration in which the first lens has a negative power and the second lens has a positive power. There is no problem.
[0008]
The present invention has been made in view of such a situation, and an object of the present invention is to provide a low-cost and compact imaging lens for a solid-state imaging device having good optical performance.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an imaging lens according to a first aspect of the present invention is an imaging lens having two lenses that forms an image on a solid-state imaging device, and has a positive surface having a convex surface facing the object side in order from the object side. It comprises a meniscus-shaped first lens and a negative meniscus-shaped second lens with a concave surface facing the image surface side, and satisfies the following conditional expression (I).
| F2 | / f1 <25 (I)
However,
f1: focal length of the first lens,
f2: focal length of the second lens,
It is.
[0010]
An imaging lens according to a second aspect of the present invention is an imaging lens having two lenses that forms an image on a solid-state imaging device, and a positive meniscus first lens having a convex surface facing the object side in order from the object side; The negative lens is constituted by a negative meniscus second lens having a concave surface facing the image surface side, and satisfies the following conditional expression (II).
0.1 <T1 / f <0.5 (II)
However,
T1: on-axis lens thickness of the first lens,
f: focal length of the whole system,
It is.
[0011]
An imaging lens according to a third aspect is characterized in that, in the configuration of the first or second aspect, the following conditional expression (III) is satisfied.
1.4 <f / Y ′ <1.9 (III)
However,
f: focal length of the whole system,
Y ': maximum image height,
It is.
[0012]
An imaging lens according to a fourth aspect is characterized in that, in the configuration of any one of the first to third aspects, the following conditional expression (IV) is satisfied.
V2> 40 (IV)
However,
V2: Abbe number of the second lens,
It is.
[0013]
An imaging lens according to a fifth aspect of the present invention is the imaging lens according to any one of the first to fourth aspects, further comprising an aperture stop on the object side of the first lens.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of an imaging lens according to the present invention will be described with reference to the drawings. FIGS. 1 to 4 each show an optical cross section of a lens configuration according to the first to fourth embodiments. Each of the imaging lenses of the embodiments is a single focus lens for imaging (for example, for a digital camera) for forming an optical image on a solid-state imaging device (for example, CCD). Then, in order from the object side, an aperture stop (ST), a positive meniscus-shaped first lens (L1) having a convex surface facing the object side, and a negative meniscus-shaped second lens having a concave surface facing the image surface side (L2), and a parallel flat plate-shaped glass filter (GF) corresponding to an optical low-pass filter or the like is arranged on the image plane side. In the first embodiment, the second lens (L2) is a plastic lens, and in the second to fourth embodiments, the first and second lenses (L1, L2) are both plastic lenses. In the first to fourth embodiments, all lens surfaces (r2 to r5) are aspherical.
[0015]
As in each of the embodiments, a positive / negative lens type in which the arrangement of power (an amount defined by the reciprocal of the focal length) is a positive meniscus lens (L1) having a convex surface facing the object side and a concave surface facing the image surface side , And the negative meniscus lens (L2) directed toward the lens enables to well balance the exit pupil position, optical performance, cost and compactness required for the imaging lens for the solid-state imaging device. I do. The conditions for achieving this effectively will be described below.
[0016]
Here, the conditional expressions that should be satisfied by the imaging lens of each embodiment, that is, the conditional expressions that should be satisfied by the imaging lens of the type described in each embodiment, will be described. However, it is not necessary to satisfy all the conditional expressions described below at the same time, and if the individual conditional expressions are individually satisfied according to the optical configuration, it is possible to achieve the corresponding operation and effect. Of course, it is needless to say that satisfying a plurality of conditional expressions is more desirable from the viewpoint of optical performance, miniaturization, assembly, and the like.
[0017]
It is desirable to satisfy the following conditional expressions (I).
| F2 | / f1 <25 (I)
However,
f1: focal length of the first lens (L1),
f2: focal length of the second lens (L2),
It is.
[0018]
Conditional expression (I) mainly defines a condition range for balancing the total length and the aberration. If the upper limit of conditional expression (I) is exceeded, the power of the second lens (L2) will be too weak, which will be advantageous for aberration correction, but will increase the total length.
[0019]
It is desirable to satisfy the following conditional expressions (II).
0.1 <T1 / f <0.5 (II)
However,
T1: on-axis lens thickness of the first lens (L1),
f: focal length of the whole system,
It is.
[0020]
Conditional expression (II) defines a condition range for mainly balancing lateral chromatic aberration and manufacturability of the lens with respect to the first lens (L1). If the upper limit of conditional expression (II) is exceeded, it becomes difficult to satisfactorily correct lateral chromatic aberration. On the other hand, if the lower limit of the conditional expression (II) is exceeded, there arises a problem that the lens peripheral portion is too thin to be manufactured.
[0021]
It is desirable to satisfy the following conditional expressions (III), and it is more desirable to satisfy at least one of the conditional expressions (I) and (II).
1.4 <f / Y ′ <1.9 (III)
However,
f: focal length of the whole system,
Y ': maximum image height,
It is.
[0022]
Conditional expression (III) defines a condition range for balancing the total lens length and the front lens diameter. If the lower limit of conditional expression (III) is exceeded, the diameter of the front lens becomes large, which causes an increase in the diameter of the imaging lens device in the radial direction, and makes it difficult to correct distortion. Conversely, if the upper limit of conditional expression (III) is exceeded, the overall length of the optical system will be large, and the size of the imaging lens device in the optical axis (AX) direction will be increased.
[0023]
It is desirable to satisfy the following conditional expressions (IV), and it is more desirable to satisfy at least one of the conditional expressions (I) to (III).
V2> 40 (IV)
However,
V2: Abbe number of the second lens (L2),
It is.
[0024]
Conditional expression (IV) defines a condition range for chromatic aberration correction of the second lens (L2). If the value falls outside the range of the conditional expression (IV), the chromatic aberration of the second lens (L2) is insufficiently corrected, and the chromatic aberration is deteriorated as a whole.
[0025]
It is preferable to satisfy the following conditional expression (V), and it is more preferable to satisfy at least one of the conditional expressions (I) to (IV).
0.13 <TA / f <0.41 (V)
However,
TA: axial air gap between the first lens (L1) and the second lens (L2);
f: focal length of the whole system,
It is.
[0026]
Conditional expression (V) mainly defines a condition range for balancing the total length and the aberration. If the upper limit of conditional expression (V) is exceeded, it will be advantageous for aberration correction, but will cause an increase in the overall length. Conversely, when the value goes below the lower limit of the conditional expression (V), it is advantageous in terms of shortening the total length, but the deterioration of aberration (particularly, the deterioration of distortion and the curvature of field) becomes remarkable.
[0027]
As in each embodiment, it is desirable to have an aperture stop (ST) on the object side of the first lens (L1). By disposing the aperture stop (ST) on the object side of the first lens (L1), it becomes possible to make the exit pupil position farther. In each embodiment, a plastic lens and an aspherical surface are used. However, it is desirable that both the first lens (L1) and the second lens (L2) are plastic lenses, and that the first lens (L1) ) And the second lens (L2) preferably have at least one aspheric surface. It is effective to form the two lenses (L1 and L2) with plastic lenses in order to reduce the cost of the imaging lens. Providing at least one aspheric surface on each of the two lenses (L1, L2) has a great effect on correcting spherical aberration, coma aberration, and distortion.
[0028]
The imaging lens according to each of the embodiments includes only a refraction lens that deflects an incident light beam by refraction (that is, a lens of a type in which deflection is performed at an interface between media having different refractive indices). Not exclusively. For example, a diffractive lens that deflects an incident light beam by diffraction, a hybrid refractive / diffractive lens that deflects an incident light beam by a combination of diffraction and refraction, and a refractive index distribution type that deflects an incident light beam according to a refractive index distribution in a medium. A lens or the like may be used. However, for the gradient index lens whose refractive index changes in the medium, a complicated manufacturing method causes an increase in cost. Therefore, in the imaging lens according to the present invention, a homogeneous material lens is used as the two lenses (L1, L2). It is desirable.
[0029]
In each embodiment, by arranging a surface having no optical power (for example, a reflection surface, a refraction surface, and a diffraction surface) in the optical path, the optical path can be bent before, after, or in the middle of the imaging lens. Good. The bending position may be set as needed, and by appropriately bending the optical path, it is possible to achieve an apparently thinner and more compact digital input device (such as a digital camera) equipped with an imaging lens. .
[0030]
The imaging lens of each embodiment is suitable for use as a small imaging lens for a digital input device. By combining the imaging lens with an optical low-pass filter or a solid-state imaging device, an image of a subject is optically captured to be electrically operated. An imaging lens device that outputs as a general signal can be configured. The imaging lens device is a camera used for capturing a still image or a moving image of a subject {for example, a digital camera; a video camera; a digital video unit, a personal computer, a mobile computer, a pen-type scanner, a mobile phone, and a personal digital assistant (PDA: Personal). A main component of the camera｝ built in or externally attached to a Digital Assistant, etc., and includes, for example, an imaging lens that forms an optical image of an object, an optical low-pass filter, and an imaging lens in order from the object (subject) side. And a solid-state imaging device that converts the formed optical image into an electric signal.
[0031]
Therefore, each of the embodiments described above includes inventions (i) to (vi) having the following configurations, and the configuration realizes a low-cost and compact imaging lens device having good optical performance. can do. When this is applied to a digital camera or the like, it is possible to contribute to higher performance, higher function, lower cost and compactness of the camera.
(I) An imaging lens device including an imaging lens that forms an optical image, and a solid-state imaging device that converts an optical image formed by the imaging lens into an electric signal, wherein the imaging lens is an object. From the side, in order from the side, the first lens has a positive meniscus shape having a convex surface facing the object side, and the second lens has a negative meniscus shape having a concave surface facing the image surface side. An imaging lens device satisfying at least one of (I) to (V).
(Ii) The imaging lens device according to (i), further including an aperture stop on the object side of the first lens.
(Iii) The imaging lens device according to (i) or (ii), wherein each of the first lens and the second lens has at least one aspheric surface.
(Iv) The imaging lens device according to any one of (i) to (iii), wherein both the first lens and the second lens are formed of plastic lenses.
(V) The imaging lens device according to any one of (i) to (iv) above, wherein the first lens and the second lens are both formed of a homogeneous material lens.
[0032]
As the solid-state imaging device, for example, a CCD including a plurality of pixels, a CMOS (Complementary Metal Oxide Semiconductor) sensor, or the like is used, and an optical image formed by an imaging lens is converted into an electric signal by the solid-state imaging device. An optical image to be formed by the imaging lens is generated when it is converted into an electric signal by passing through an optical low-pass filter having a predetermined cut-off frequency characteristic determined by the pixel pitch of the solid-state imaging device. The spatial frequency characteristics are adjusted so that so-called aliasing noise is minimized. The signal generated by the solid-state image sensor is subjected to predetermined digital image processing and image compression processing as necessary, and is recorded as a digital video signal in a memory (semiconductor memory, optical disk, etc.). The signal is transmitted to another device through the device or converted into an infrared signal.
[0033]
Note that the optical low-pass filter disposed between the final surface of the imaging lens and the solid-state imaging device is formed of a glass filter (GF) in each embodiment, but is compatible with a digital input device used. Anything should do. For example, a birefringent low-pass filter made of quartz or the like in which a predetermined crystal axis direction is adjusted, or a phase-type low-pass filter that achieves required optical cutoff frequency characteristics by a diffraction effect can be applied. is there.
[0034]
【Example】
Hereinafter, the imaging lens embodying the present invention will be described more specifically with reference to construction data and the like. Examples 1 to 4 described here correspond to the above-described first to fourth embodiments, respectively. The lens configuration diagrams (FIGS. 1 to 4) representing the first to fourth embodiments are as follows. , And corresponding lens configurations of Examples 1 to 4, respectively. In the construction data of each embodiment, ri (i = 1, 2, 3,...) Is the radius of curvature (mm) of the i-th surface counted from the object side, and di (i = 1, 2, 3,. ..) indicates the i-th axial distance (mm) counted from the object side, and Ni (i = 1, 2, 3) and νi (i = 1, 2, 3) are counted from the object side. The refractive index (Nd) and Abbe number (νd) of the i-th optical element with respect to the d-line are shown. The focal length (f, mm) and F-number (FNO) of the entire system are shown together with other data, and the corresponding values of each conditional expression are shown in Table 1.
[0035]
The surface with the * mark on the radius of curvature ri indicates a refractive optical surface having an aspherical shape or a surface having a refracting action equivalent to the aspherical surface, and the following expression (AS) representing the surface shape of the aspherical surface Shall be defined as The aspherical surface data of each example is shown together with other data.
^{X (H) = (C0 ·} H 2) / {1 + √ (1-ε · C0 2 · H 2)} + Σ (Ai · H i) ... (AS)
However, in the expression (AS),
X (H): displacement amount in the optical axis (AX) direction at the position of height H (based on the surface vertex),
H: height in a direction perpendicular to the optical axis (AX),
C0: paraxial curvature (= 1 / radius of curvature),
ε: quadratic surface parameter,
Ai: i-th order aspherical coefficient (data in case of Ai = 0 is omitted),
It is.
[0036]
5 to 8 are aberration diagrams corresponding to the first to fourth embodiments. In FIGS. 5 to 8, (A) is a spherical aberration diagram, (B) is an astigmatism diagram, and (C) is a diagram. It is a distortion diagram {FNO: F number, Y ′: maximum image height (mm)}. In the spherical aberration diagram, the solid line (d) represents the amount of spherical aberration (mm) with respect to the d line, the one-dot chain line (g) the g line, the two-dot chain line (c) with respect to the c line, and the dashed line (SC) represents the sine. It represents the condition unsatisfactory amount (mm). In the astigmatism diagram, a dashed line (DM) represents a meridional surface, and a solid line (DS) represents each astigmatism (mm) with respect to a d-line on a sagittal surface. In the distortion diagrams, the solid line represents the distortion (%) with respect to the d-line.
[0037]

[0038]
[Aspherical surface data of second surface (r2)]
ε = −0.40818 × 10, A4 = 0.33779, A6 = −0.18548, A8 = 0.12890, A10 = −0.944438 × 10 ⁻²
[Aspherical surface data of third surface (r3)]
ε = 0.10000 × 10, A4 = 0.12179 × 10 ^-1 , A6 = 0.35030, A8 = -0.60572, A10 = 0.79691
[Aspherical surface data of fourth surface (r4)]
ε = 0.10000 × 10, A4 = −0.12855, A6 = −0.15977, A8 = 0.28053, A10 = −0.23948
[Aspherical surface data of fifth surface (r5)]
ε = 0.10000 × 10, A4 = −0.72820 × 10 ⁻¹ , A6 = 0.83001 × 10 ⁻² , A8 = −0.69268 × 10 ⁻³ , A10 = −0.83004 × 10 ⁻³
[0039]

[0040]
[Aspherical surface data of second surface (r2)]
ε = −0.46326 × 10, A4 = 0.35512, A6 = −0.19378, A8 = 0.14280, A10 = −0.18959 × 10 ⁻¹
[Aspherical surface data of third surface (r3)]
ε = 0.10000 × 10, A4 = 0.44728 × 10 -1, A6 = 0.30295, A8 = -0.48503, A10 = 0.63805
[Aspherical surface data of fourth surface (r4)]
ε = 0.10000 × 10, A4 = −0.92377 × 10 ⁻¹ , A6 = −0.77511 × 10 ⁻¹ , A8 = 0.97891 × 10 ⁻¹ , A10 = −0.57011 × 10 ⁻¹
[Aspherical surface data of fifth surface (r5)]
ε = 0.10000 × 10, A4 = −0.61335 × 10 ⁻¹ , A6 = −0.48871 × 10 ⁻² , A8 = 0.04637 × 10 ⁻² , A10 = −0.13823 × 10 ⁻²
[0041]

[0042]
[Aspherical surface data of second surface (r2)]
ε = −0.46855 × 10, A4 = 0.32658, A6 = −0.20012, A8 = 0.173345, A10 = −0.48587 × 10 ⁻¹
[Aspherical surface data of third surface (r3)]
ε = 0.10000 × 10, A4 = 0.36697 × 10 ⁻¹ , A6 = 0.29767, A8 = −0.43590, A10 = 0.53792
[Aspherical surface data of fourth surface (r4)]
ε = 0.10000 × 10, A4 = −0.95066 × 10 ⁻¹ , A6 = −0.26867 × 10 ⁻¹ , A8 = 0.34964 × 10 ⁻¹ , A10 = −0.21189 × 10 ⁻¹
[Aspherical surface data of fifth surface (r5)]
ε = 0.10000 × 10, A4 = −0.53454 × 10 ⁻¹ , A6 = −0.64541 × 10 ⁻² , A8 = 0.37370 × 10 ⁻² , A10 = −0.11340 × 10 ⁻²
[0043]

[0044]
[Aspherical surface data of second surface (r2)]
ε = −0.70202 × 10, A4 = 0.96112, A6 = −0.16643 × 10, A8 = 0.265598 × 10, A10 = −0.17468 × 10
[Aspherical surface data of third surface (r3)]
ε = 0.10000 × 10, A4 = -0.11476, A6 = 0.19645 × 10, A8 = -0.54091 × 10, A10 = 0.85369 × 10
[Aspherical surface data of fourth surface (r4)]
ε = 0.10000 × 10, A4 = −0.20459, A6 = −0.15755, A8 = 0.39537, A10 = −0.29209
[Aspherical surface data of fifth surface (r5)]
ε = 0.10000 × 10, A4 = 0.10628 × 10 ⁻¹ , A6 = −0.23532, A8 = 0.195577, A10 = −0.673370 × 10 ⁻¹
[0045]
[Table 1]

[0046]
【The invention's effect】
As described above, according to the present invention, a low-cost and compact imaging lens for a solid-state imaging device having good optical performance can be realized. When the imaging lens according to the present invention is used for a digital input device such as a camera mounted on a mobile phone or a digital camera, it is possible to contribute to high performance, high function, low cost, and compactness of the device.
[Brief description of the drawings]
FIG. 1 is a lens configuration diagram of a first embodiment (Example 1).
FIG. 2 is a lens configuration diagram of a second embodiment (Example 2).
FIG. 3 is a lens configuration diagram of a third embodiment (Example 3).
FIG. 4 is a lens configuration diagram of a fourth embodiment (Example 4).
FIG. 5 is an aberration diagram of the first embodiment.
FIG. 6 is an aberration diagram of the second embodiment.
FIG. 7 is an aberration diagram of the third embodiment.
FIG. 8 is an aberration diagram of the fourth embodiment.
[Explanation of symbols]
ST: Aperture stop L1: First lens L2: Second lens GF: Glass filter AX: Optical axis

Claims (5)

An imaging lens having two lenses for forming an image on a solid-state imaging device, comprising a first meniscus positive lens having a convex surface facing the object side and a negative lens having a concave surface facing the image surface in order from the object side. An imaging lens comprising a meniscus-shaped second lens and satisfying the following conditional expression (I):
| F2 | / f1 <25 (I)
However,
f1: focal length of the first lens,
f2: focal length of the second lens,
It is. An imaging lens having two lenses for forming an image on a solid-state imaging device, comprising a first meniscus positive lens having a convex surface facing the object side and a negative lens having a concave surface facing the image surface in order from the object side. An imaging lens characterized by satisfying the following conditional expression (II):
0.1 <T1 / f <0.5 (II)
However,
T1: on-axis lens thickness of the first lens,
f: focal length of the whole system,
It is. The imaging lens according to claim 1, wherein the following conditional expression (III) is satisfied;
1.4 <f / Y ′ <1.9 (III)
However,
f: focal length of the whole system,
Y ': maximum image height,
It is. The imaging lens according to any one of claims 1 to 3, wherein the following conditional expression (IV) is satisfied;
V2> 40 (IV)
However,
V2: Abbe number of the second lens,
It is. The imaging lens according to claim 1, further comprising an aperture stop on an object side of the first lens.

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