JP2000180718A - Photographic lens system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive compact photographic lens system having high optical performance. SOLUTION: This system is provided with a front group F, a diaphragm A and a rear group R in order from an object side. The front group F is constituted of two lenses, a negative lens FL1 made of plastic material and a positive lens FL2 made of glass material. The rear group R is provided with a plastic positive lens RL2, which is arranged closest to the image side and a lens RL2 formed of glass material on the object side of the positive lens RL2. In this case, a conditional inequality |f×fa/Ha2+f×fb/Hb2|<5 is satisified. Here (f) represents the focal distance of the whole system, (fa) the focal distance of the negative lens FL1, (fb) the focal length of the positive lens RL2, Ha the incident height of on-axis F-numbered light on the negative lens FL1, Hb the incident height of on-axis F-numbered light on the positive lens RL2, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small photographing lens system, and more particularly, to a digital input device.
The present invention relates to a low-cost and compact photographing lens system suitable for (a digital still camera, a digital video camera, etc.).

[0002]

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 available to individual users. It is becoming popular. Such digital cameras are expected to be increasingly used as image information input devices in the future.

[0003] CCDs mounted on digital cameras
(Charge Coupled Device) and other solid-state imaging devices have been miniaturized, and accordingly, digital cameras have been required to be further miniaturized. For this reason, there is a strong demand for a compact photographing lens system which occupies the largest volume in a digital input device. Furthermore, due to the recent price competition, demands for cost reduction in photographing lens systems have been increasing. In response to the demands described above, a compact photographing lens system for a digital camera having a relatively small number of lenses of 5 to 6 is disclosed in JP-A-9-43512, JP-A-9-166748, and JP-A-10-20188. In each publication. In addition, since the taking lens system for a lens shutter camera using a silver halide film has been remarkably downsized in recent years, it can be conceived to use this as a taking lens system for a digital camera.

[0004]

The photographing lens systems described in the above publications are compact, but cost reduction has not been achieved because all lenses are made of glass. In addition, when a photographing lens system for a lens shutter camera is used as it is in a digital camera, the light-collecting performance of a microlens provided on the front surface of a solid-state imaging device cannot be sufficiently exhibited. This is because in an imaging lens system for a lens shutter camera, the exit pupil is located near the image plane, and an off-axis light beam emitted from the imaging lens system is obliquely incident on the image plane. Therefore, the light-collecting performance of the microlens is not sufficiently exhibited, and a problem occurs that the brightness of the image is extremely changed between the central portion and the peripheral portion of the image. If the position of the exit pupil of the photographing lens system is to be moved away from the image plane in order to solve this problem, the size of the entire photographing lens system cannot be avoided.

[0005] The present invention has been made in view of such circumstances, and has as its object to provide a low-cost and compact photographing lens system having good optical performance.

[0006]

In order to achieve the above object, a photographic lens system according to a first aspect of the present invention is a photographic lens system having a front group, an aperture, and a rear group in order from the object side. The front group includes, in order from the object side, a negative lens made of a plastic material and a positive lens made of a glass material. And the object side of the positive lens includes only a lens made of a glass material, and further satisfies the following conditional expression. | F × fa / Ha ² + f × fb / Hb ² | <5 where f: focal length of the whole system, fa: focal length of the negative lens made of plastic material in the front group, fb: plastic material in the rear group The focal length of the positive lens consisting of: Ha: the incident height of the axial F-number ray on the negative lens made of plastic material in the front group, and the Hb: the axial F-number on the positive lens made of plastic material in the rear group. The incident height of the light beam.

A photographic lens system according to a second aspect of the present invention is characterized in that, in the configuration of the first aspect, the following conditional expression is further satisfied. 0.01 <f / fF <0.91 where fF is the focal length of the front group.

According to a third aspect of the present invention, in the photographic lens system according to the first aspect, at least one surface of the negative lens in the front group is an aspheric surface, and a maximum effective radius of the aspheric surface is ymax. , 0.7ymax <y <1.0ymax, and the following conditional expression is satisfied for an arbitrary height y in the vertical direction of the optical axis. 0.01 <| (x-x0) / (N'-N) | <2.0 where x: displacement in the optical axis direction at a height perpendicular to the optical axis of the aspherical surface (mm; X0: Displacement in the optical axis direction at a height perpendicular to the optical axis of the reference aspherical surface (mm; object side direction is negative), N: From the aspherical surface The refractive index of the medium on the object side for the d-line, N ': the refractive index of the medium on the image side of the aspherical surface for the d-line.

According to a fourth aspect of the present invention, in the photographic lens system according to the first aspect of the present invention, at least one surface of the most image-side positive lens in the rear group is an aspheric surface, and the maximum effective radius of the aspheric surface is reduced. When ymax is satisfied, the following conditional expression is satisfied for an arbitrary height y in the optical axis vertical direction satisfying 0.7ymax <y <1.0ymax. 0.01 <| (x-x0) / (N'-N) | <2.0 where x: displacement in the optical axis direction at a height perpendicular to the optical axis of the aspherical surface (mm; X0: Displacement in the optical axis direction at a height perpendicular to the optical axis of the reference aspherical surface (mm; object side direction is negative), N: From the aspherical surface The refractive index of the medium on the object side for the d-line, N ': the refractive index of the medium on the image side of the aspherical surface for the d-line.

A photographic lens system according to a fifth aspect of the present invention is the photographic lens system according to the first aspect, wherein the rear group includes, in order from the object side, a cemented lens of a biconcave lens and a biconvex lens, and a positive lens made of a plastic material. , And is characterized by the following.

A photographic lens system according to a sixth aspect of the present invention is the photographic lens system according to the first aspect, wherein the rear group includes, in order from the object side, a cemented lens of a biconvex lens and a biconcave lens, and a positive lens made of a plastic material. , And is characterized by the following.

A photographic lens system according to a seventh aspect is characterized in that, in the constitution of the fifth or sixth aspect, the cemented lens in the rear group satisfies the following conditional expression. −0.05 <f / fS <0.25 where fS is the focal length of the cemented lens in the rear group.

According to an eighth aspect of the present invention, in the imaging lens system according to the fifth or sixth aspect, the most image-side positive lens in the rear group satisfies the following conditional expression. . 0.23 <f / fP <0.99, where fP is the focal length of the most image-side positive lens in the rear group.

A photographic lens system according to a ninth aspect of the present invention comprises
An eighth aspect of the invention is characterized in that the following conditional expression is further satisfied. 1 <img × R <15 where img: maximum image height, R: effective diameter of the surface closest to the image.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A photographic lens system embodying the present invention will be described below with reference to the drawings. In this specification, “power” refers to an amount defined by the reciprocal of the focal length, and the deflecting action by power is not limited to deflecting at an interface between media having different refractive indices, but is caused by diffraction. It also includes those due to deflection or deflection due to the refractive index distribution in the medium. In addition, the “refractive power” particularly refers to the “power” resulting from a deflecting action generated at an interface between media having different refractive indexes.

FIGS. 1 to 8 are lens configuration diagrams respectively corresponding to the photographing lens systems of the first to eighth embodiments.
The lens arrangement of each embodiment is shown in a sectional view. In each lens configuration diagram, the surface marked with ri (i = 1, 2, 3, ...) is the i-th surface counted from the object (i.e., the subject) side, and ri is marked *. The surface is aspheric. Also, di (i = 1,2,3, ...)
Is the ith axial top surface distance counted from the object side. In each of the embodiments, in general, in order from the object side, a front group (F) having a positive power, and an aperture (A)
And a rear lens unit (R) having a positive power, and a low-pass filter (LPF).

In the first embodiment (FIG. 1), each group
(F, R) is configured as follows in order from the object side. The front group (F) includes a biconcave negative lens (FL1) and a biconvex positive lens (FL2). The negative lens (FL1) is made of a plastic material, and the positive lens (FL2) is made of a glass material. The image side surface of the negative lens (FL1) is aspheric. The rear group (R) includes a cemented lens (RL1) including a biconcave lens and a biconvex lens, and a biconvex positive lens (RL2). The cemented lens (RL1) is made of a glass material, and the positive lens (RL2) is made of a plastic material. The object side surface of the positive lens (RL2) is aspheric.

In the second and third embodiments (FIGS. 2 and 3), each group (F, R) is configured as follows in order from the object side. The front group (F) includes a biconcave negative lens (FL1) and a biconvex positive lens (FL2). Negative lens (FL1)
Is made of a plastic material, and the positive lens (FL2) is made of a glass material. Both surfaces of the negative lens (FL1) are aspherical. The rear group (R) includes a cemented lens (RL1) including a biconcave lens and a biconvex lens, and a positive meniscus lens (RL2) convex to the object side. Cemented lens
(RL1) is made of a glass material, and the positive meniscus lens (RL2) is made of a plastic material. The object side surface of the positive meniscus lens (RL2) is aspheric.

In the fourth embodiment (FIG. 4), each group
(F, R) is configured as follows in order from the object side. The front group (F) includes a biconcave negative lens (FL1) and a biconvex positive lens (FL2). The negative lens (FL1) is made of a plastic material, and the positive lens (FL2) is made of a glass material. Both surfaces of the negative lens (FL1) are aspherical. The rear group (R) includes a cemented lens (RL1) including a biconcave lens and a biconvex lens, and a biconvex positive lens (RL2). The cemented lens (RL1) is made of a glass material, and the positive lens (RL2) is made of a plastic material. The object side surface of the positive lens (RL2) is aspheric.

In the fifth and sixth embodiments (FIGS. 5 and 6), each group (F, R) is configured as follows in order from the object side. The front group (F) includes a biconcave negative lens (FL1) and a biconvex positive lens (FL2). Negative lens (FL1)
Is made of a plastic material, and the positive lens (FL2) is made of a glass material. The image side surface of the negative lens (FL1) is aspheric. The rear group (R) includes a cemented lens (RL1) including a biconvex lens and a biconcave lens, and a biconvex positive lens (RL
2). The cemented lens (RL1) is made of a glass material, and the positive lens (RL2) is made of a plastic material. Further, both surfaces of the positive lens (RL2) are aspherical.

In the seventh and eighth embodiments (FIGS. 7 and 8), each group (F, R) is configured as follows in order from the object side. The front group (F) includes a biconcave negative lens (FL1) and a biconvex positive lens (FL2). Negative lens (FL1)
Is made of a plastic material, and the positive lens (FL2) is made of a glass material. Both surfaces of the negative lens (FL1) are aspherical. The rear group (R) is a cemented lens (RL1) composed of a biconvex lens and a biconcave lens, and a biconvex positive lens (RL2).
And is composed of The cemented lens (RL1) is made of a glass material, and the positive lens (RL2) is made of a plastic material. Further, both surfaces of the positive lens (RL2) are aspherical.

As described above, the taking lens system of each embodiment includes the front unit (F), the stop (A), and the rear unit (R) in order from the object side, and the front unit (F) is In order from the side, a negative lens (FL1) made of a plastic material and a positive lens (FL2) made of a glass material, and the rear group (R) is made up of a positive lens (RL2) made of a plastic material. In addition to the lens closest to the image, the object side of the positive lens (RL2) includes only a lens (RL1) made of a glass material. With this configuration of the taking lens system, it is possible to suppress a change in the lens back due to a temperature change, which is a problem when using a lens made of a plastic material. further,
Even if the size is reduced, a low-cost photographing lens system in which aberration is favorably corrected can be realized.

Further, as in the first to fourth embodiments,
In order from the object side, a cemented lens of a biconcave lens and a biconvex lens (RL1), and a positive lens made of a plastic material (RL2)
And a rear lens unit (R), or as in the fifth to eighth embodiments, in order from the object side, a cemented lens (RL1) of a biconvex lens and a biconcave lens, and a positive lens made of a plastic material. It is desirable to form the rear unit (R) with the lens (RL2). By configuring the cemented lens (RL1) with a negative lens and a positive lens, handling and the configuration of the lens frame are simplified. Further, since no air gap is required, it is advantageous in achieving compactness.

In each embodiment, when focusing from an infinity in-focus condition to a close object distance, the front unit (F) and the rear unit
A so-called whole extension focusing method in which all components such as (R) are extended toward the object side is employed. However, as for the focusing method,
(F), front group (F) and rear group (R) while moving the rear group (R), etc.
Focusing system, such as changing the distance between the lens and the front group (F) or only part of the front group (F), or moving only the rear group (R) or part of the rear group (R). It may be appropriately selected.

Next, conditional expressions which should be satisfied by the photographic lens system of each embodiment will be described. It is not necessary that each embodiment satisfies all the conditional expressions described below at the same time. If each individual conditional expression is satisfied independently, it is possible to achieve a 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, and assembly.

It is desirable to satisfy the following conditional expression (1), and it is more desirable to satisfy the conditional expression (1 ′). | F × fa / Ha ² + f × fb / Hb ² | <5 (1) | f × fa / Ha ² + f × fb / Hb ² | <2.5 (1 ′) where f is the focal length of the entire system , Fa: negative lens (FL) made of plastic material in the front group (F)
1) Focal length, fb: Positive lens (RL) made of plastic material in rear group (R)
2) Focal length, Ha: negative lens (FL) made of plastic material in front group (F)
Hb: height of incidence of on-axis F-number ray to 1), Hb: positive lens (RL) made of plastic material in rear group (R)
The incident height of the on-axis F-number ray to 2).

Conditional expression (1) defines a condition range for suppressing a change in lens back mainly due to a temperature change. When the value exceeds the upper limit of the conditional expression (1), a change in lens back due to a temperature change becomes large, so that performance deterioration due to a temperature change becomes remarkable. Conditional expression (1 ′) defines a more desirable condition range than conditional expression (1) in suppressing the change of the lens back.

It is desirable to satisfy the following conditional expression (2). 0.01 <f / fF <0.91 (2) where fF is the focal length of the front group (F).

Conditional expression (2) mainly defines a condition range for balancing the total length and the aberration. Exceeding the lower limit of conditional expression (2) is advantageous for aberration correction, but causes an increase in the overall length. In addition, the diameter of the front lens increases with an increase in the overall length, which significantly increases the size of the photographic lens system. Conversely, exceeding the upper limit of conditional expression (2) is advantageous for shortening the overall length, but causes aberration degradation.
(Especially, distortion and deterioration of field curvature) become remarkable.

At least one of the negative lens (FL1) in the front group (F)
If the surface is an aspheric surface and the maximum effective radius of the aspheric surface is ymax, the following conditional expression (3) is satisfied for an arbitrary height y in the vertical direction of the optical axis where 0.7ymax <y <1.0ymax. It is desirable. Further, at least one surface of the most image-side positive lens (RL2) in the rear group (R) is an aspheric surface, and the maximum effective radius of the aspheric surface is ym.
When ax is set, it is preferable that the following conditional expression (3) is satisfied for an arbitrary height y in the vertical direction of the optical axis such that 0.7ymax <y <1.0ymax. It is more desirable that at least one surface of the negative lens (FL1) and at least one surface of the positive lens (RL2) are both aspheric surfaces that satisfy conditional expression (3). 0.01 <| (x-x0) / (N'-N) | <2.0 (3) where x is the optical axis at a height perpendicular to the aspherical optical axis (AX).
Displacement in (AX) direction (mm; object side direction is negative), x0: Optical axis (AX) direction at a height perpendicular to optical axis (AX) of aspherical reference spherical surface Displacement (mm; negative in the object side direction), N: refractive index for d-line of the medium closer to the object side than the aspherical surface, N ': refractive index for the d-line of the medium closer to the image side than the aspherical surface .

Note that x representing the surface shape of the aspherical surface and x0 representing the surface shape of the reference spherical surface are specifically expressed by the following equations (AS) and (RE), respectively, with reference to the surface vertices. . x = {C0 · y ² } / {1 + √ (1-ε · C0 ² · y ² )} + Σ (Ai · y ⁱ )… (AS) x0 = {C0 · y ² } / {1 + √ ^{(1-C0 2 · y 2} )} ... (RE) in the formula (AS) and (RE), y: an optical axis (AX) with respect to vertical height, C0: the reference spherical curvature (i.e. Reference curvature of aspherical surface), ε: quadratic surface parameter, Ai: i-th order aspherical coefficient.

Conditional expression (3) mainly defines a condition range for appropriately correcting distortion and curvature of field. Conditional expression
If the lower limit of (3) is exceeded, the positive distortion will increase and the image plane will fall more toward the over side. vice versa,
When the value exceeds the upper limit of the conditional expression (3), the negative distortion becomes large, and the inclination of the image surface to the under side becomes large,
It cannot be put to practical use as a taking lens system. When there are a plurality of aspherical surfaces as in the seventh embodiment and the like, if at least one surface satisfies the conditional expression (3), the other aspherical surfaces balance the other aberrations. Considering conditional expression
You do not have to satisfy (3).

It is desirable that the cemented lens (RL1) in the rear group (R) satisfies the following conditional expression (4). -0.05 <f / fS <0.25 (4) where fS is the focal length of the cemented lens (RL1) in the rear group (R).

Conditional expression (4) mainly defines a condition range for balancing the total length and the aberration. Exceeding the lower limit of conditional expression (4) is advantageous for aberration correction, but causes an increase in the overall length. In addition, the diameter of the front lens increases with an increase in the overall length, which significantly increases the size of the photographic lens system. Conversely, if the value exceeds the upper limit of conditional expression (4), it is advantageous to shorten the overall length.
(Especially, distortion and deterioration of field curvature) become remarkable.

The most image-side positive lens (RL2) in the rear group (R) is
It is desirable to satisfy the following conditional expressions (5). 0.23 <f / fP <0.99 (5) where, fP is the focal length of the most image-side positive lens (RL2) in the rear group (R).

Conditional expression (5) mainly defines a condition range for balancing coma. If the lower limit of conditional expression (5) is exceeded, coma will deteriorate and the adverse effect on higher-order chromatic aberration of magnification will increase. On the other hand, when the value exceeds the upper limit of the conditional expression (5), the coma aberration is deteriorated and the adverse effect on the astigmatism is increased.

It is desirable to satisfy the following conditional expression (6). 1 <img × R <15 (6) where img: maximum image height, R: effective diameter (diameter) of the surface closest to the image.

Conditional expression (6) mainly defines the size and aberration of the photographic lens system and the condition range for appropriately maintaining the conditions specific to the video camera. 2. Description of the Related Art A solid-state imaging device (for example, a CCD) used for a video camera is generally provided with a microlens on the front surface of each light-receiving element for improving light-collecting properties. In order to sufficiently exhibit the characteristics of the microlens, it is necessary to make the light beam incident substantially parallel to the optical axis of the microlens (that is, substantially perpendicular to the light receiving surface of each light receiving element). For that purpose, the taking lens system is required to be telecentric on the image side. Conditional expression (6)
Exceeds the upper limit, it becomes unnecessary to be substantially telecentric, the negative distortion becomes large, and the image plane falls to the under side remarkably. Conversely, conditional expression (6)
If the lower limit is exceeded, it is difficult to satisfy the condition of being substantially telecentric, and even if satisfied, the back focus becomes unnecessarily long, resulting in an increase in the size of the photographing lens system itself.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a photographic lens system embodying the present invention will be described more specifically with reference to construction data, aberration diagrams, and the like. In addition, the following Examples 1-8
Correspond to the above-described first to eighth embodiments, respectively, and are lens configuration diagrams showing the first to eighth embodiments.
(FIGS. 1 to 8) show the corresponding lens configurations of Examples 1 to 8, respectively.

In the construction data of each embodiment, ri (i = 1, 2, 3,...) Is the radius of curvature of the i-th surface counted from the object side, and di (i = 1, 2, 3,. ..) indicates the i-th axial top surface distance counted from the object side, and Ni (i = 1,2,3, ...), νi (i = 1,2,
3,...) Represent the refractive index (Nd) and Abbe number (νd) of the i-th optical element counted from the object side with respect to the d-line. The focal length f and the F-number FNO of the entire system are also shown, and the conditional expression (1),
Table 1 shows the corresponding values of (1 ′), (2), (4) to (6). Further, the surface with the * mark on the radius of curvature ri is a surface formed of an aspherical surface (not limited to a refractive optical surface having an aspherical shape, but may be a surface having a refracting action equivalent to an aspherical surface). And is defined by the above-mentioned formula (AS) representing the surface shape of the aspherical surface. Aspherical surface data and corresponding value of conditional expression (3) regarding aspherical surface {where, ymax: maximum height (maximum effective radius) in the direction perpendicular to the optical axis (AX) of the aspherical surface. } Together with other data.

9 to 16 are aberration diagrams of the first to eighth embodiments, and show, from the left, astigmatism and distortion (Y ': maximum image height) in order from the left. In each aberration diagram, the solid line (d) is the aberration for the d line, the dashed line (g) is the aberration for the g line, the two-dot chain line (c) is the aberration for the c line, and the dashed line (SC)
Indicates a sine condition, a broken line (DM) indicates astigmatism on the meridional surface, and a solid line (DS) indicates astigmatism on the sagittal surface.

[0042]

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = −0.21160 × 10 ⁻² A6 = −0.68934 × 10 ⁻⁴ A8 = −0.21582 × 10 ⁻⁴

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = −0.89304 × 10 ⁻³ A6 = 0.11368 × 10 ⁻⁴ A8 = −0.78938 × 10 ⁻⁶

[Corresponding value of conditional expression (3) for second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00022 y = 0.40ymax… (x-x0) / (N'-N) = 0.00362 y = 0.60ymax… (x-x0) / (N'-N) = 0.01960 y = 0.80ymax … (X-x0) / (N'-N) = 0.07027 y = 1.00ymax… (x-x0) / (N'-N) = 0.20843

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00027 y = 0.40ymax… (x-x0) / (N'-N) =-0.00426 y = 0.60ymax… (x-x0) / (N'-N) =-0.02122 y = 0.80ymax… (x-x0) / (N'-N) =-0.06632 y = 1.00ymax… (x-x0) / (N'-N) =-0.16297

[0047]

[Aspherical surface data of first surface (r1)] ε = 1.0000 A4 = 0.12670 × 10 ^-2 A6 = -0.52617 × 10 ^-4 A8 = 0.97357 × 10 ^-6

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = 0.30439 × 10 ^-3 A6 = -0.55298 × 10 ^-5 A8 = -0.16566 × 10 ^-4

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = -0.10163 × 10 ⁻² A6 = 0.15447 × 10 ⁻⁴ A8 = −0.14079 × 10 ⁻⁵

[Corresponding value of conditional expression (3) for first surface (r1)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00106 y = 0.40ymax… (x-x0) / (N'-N) = 0.01560 y = 0.60ymax… (x-x0) / (N'-N) = 0.06865 y = 0.80ymax ... (x-x0) / (N'-N) = 0.17929 y = 1.00ymax ... (x-x0) / (N'-N) = 0.
35391

[Corresponding value of conditional expression (3) for second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00006 y = 0.40ymax… (x-x0) / (N'-N) =-0.00083 y = 0.60ymax ... (x-x0) / (N'-N) =-0.00238 y = 0.80ymax… (x-x0) / (N'-N) = 0.00754 y = 1.00ymax… (x-x0) / (N'-N) = 0.09481

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00037 y = 0.40ymax… (x-x0) / (N'-N) =-0.00575 y = 0.60ymax… (x-x0) / (N'-N) =-0.02861 y = 0.80ymax… (x-x0) / (N'-N) =-0.09038 y = 1.00ymax… (x-x0) / (N'-N) =-0.22924

[0054]

[Aspherical surface data of first surface (r1)] ε = 1.0000 A4 = 0.17350 × 10 ⁻² A6 = −0.73617 × 10 ^-4 A8 = 0.13305 × 10 ^-5

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = 0.86937 × 10 ^-3 A6 = 0.43329 × 10 ^-4 A8 = -0.23618 × 10 ^-4

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = −0.11375 × 10 ⁻² A6 = 0.12458 × 10 ⁻⁵ A8 = −0.12147 × 10 ⁻⁵

[Corresponding value of conditional expression (3) on first surface (r1)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00234 y = 0.40ymax… (x-x0) / (N'-N) = 0.03357 y = 0.60ymax… (x-x0) / (N'-N) = 0.14134 y = 0.80ymax … (X-x0) / (N'-N) = 0.34967 y = 1.00ymax… (x-x0) / (N'-N) = 0.67241

[Corresponding value of conditional expression (3) for second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00024 y = 0.40ymax… (x-x0) / (N'-N) =-0.00386 y = 0.60ymax… (x-x0) / (N'-N) =-0.01648 y = 0.80ymax… (x-x0) / (N'-N) =-0.01838 y = 1.00ymax… (x-x0) / (N'-N) = 0.14482

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00047 y = 0.40ymax… (x-x0) / (N'-N) =-0.00751 y = 0.60ymax… (x-x0) / (N'-N) =-0.03850 y = 0.80ymax ... (x-x0) / (N'-N) =-0.12609 y = 1.00ymax ... (x-x0) / (N'-N) =-0.
33147

Example 4 f = 4.45 FNO = 2.87 [Radius of Curvature] [Spacing of Shaft Upper Surface] [Refractive Index] [Abbe Number] r1 * = − 69.893 d1 = 1.685 N1 = 1.52510 v1 = 56.38 r2 * = 3.198 d2 = 4.545 r3 = 10.683 d3 = 3.339 N2 = 1.85000 ν2 = 40.04 r4 = -11.888 d4 = 1.796 r5 = ∞ (A) d5 = 1.738 r6 = -9.557 d6 = 0.750 N3 = 1.79850 ν3 = 22.60 r7 = 6.619 d7 = 3.155 N4 = 1.77250 ν4 = 49.77 r8 = -8.758 d8 = 0.429 r9 * = 7.171 d9 = 1.915 N5 = 1.52510 ν5 = 56.38 r10 = -93.076 d10 = 0.563 r11 = ∞ d11 = 3.400 N6 = 1.51680 ν6 = 64.20 r12 = ∞

[Aspherical surface data of first surface (r1)] ε = 1.0000 A4 = 0.18944 × 10 ⁻² A6 = −0.91951 × 10 ^-4 A8 = 0.18571 × 10 ^-5

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = 0.84518 × 10 ^-3 A6 = 0.82034 × 10 ^-4 A8 = −0.46802 × 10 ^-4

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = -0.95746 × 10 ^-3 A6 = 0.20191 × 10 ^-5 A8 = -0.77487 × 10 ^-6

[Corresponding value of conditional expression (3) on first surface (r1)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00199 y = 0.40ymax… (x-x0) / (N'-N) = 0.02851 y = 0.60ymax… (x-x0) / (N'-N) = 0.11967 y = 0.80ymax … (X-x0) / (N'-N) = 0.29415 y = 1.00ymax… (x-x0) / (N'-N) = 0.55871

[Corresponding value of conditional expression (3) on second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00016 y = 0.40ymax… (x-x0) / (N'-N) =-0.00255 y = 0.60ymax… (x-x0) / (N'-N) =-0.01048 y = 0.80ymax… (x-x0) / (N'-N) =-0.00494 y = 1.00ymax… (x-x0) / (N'-N) = 0.14971

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00031 y = 0.40ymax… (x-x0) / (N'-N) =-0.00489 y = 0.60ymax… (x-x0) / (N'-N) =-0.02486 y = 0.80ymax… (x-x0) / (N'-N) =-0.07995 y = 1.00ymax… (x-x0) / (N'-N) =-0.20329

[0068]

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = −0.38963 × 10 ⁻² A6 = −0.998085 × 10 ^-4 A8 = −0.26318 × 10 ^-4

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = −0.22552 × 10 ⁻³ A6 = 0.72085 × 10 ⁻⁴ A8 = 0.68284 × 10 ⁻⁶

[Aspherical surface data of the tenth surface (r10)] ε = 1.0000 A4 = 0.21821 × 10 ⁻² A6 = 0.10796 × 10 ⁻⁴ A8 = 0.72248 × 10 ⁻⁵

[Corresponding value of conditional expression (3) for second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00023 y = 0.40ymax… (x-x0) / (N'-N) = 0.00377 y = 0.60ymax… (x-x0) / (N'-N) = 0.01977 y = 0.80ymax … (X-x0) / (N'-N) = 0.06649 y = 1.00ymax… (x-x0) / (N'-N) = 0.17928

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00006 y = 0.40ymax… (x-x0) / (N'-N) =-0.00055 y = 0.60ymax… (x-x0) / (N'-N) = 0.00154 y = 0.80ymax… (x-x0) / (N'-N) = 0.02489 y = 1.00ymax… (x-x0) / (N'-N) = 0.12727

[Corresponding value of conditional expression (3) on the tenth surface (r10)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00075 y = 0.40ymax… (x-x0) / (N'-N) =-0.01223 y = 0.60ymax… (x-x0) / (N'-N) =-0.06493 y = 0.80ymax… (x-x0) / (N'-N) =-0.22816 y = 1.00ymax… (x-x0) / (N'-N) =-0.66954

[0075]

[0076]

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = -0.30193 × 10 ^-3 A6 = 0.70895 × 10 ^-4 A8 = 0.13241 × 10 ^-5

[Aspherical surface data of the tenth surface (r10)] ε = 1.0000 A4 = 0.25310 × 10 ⁻² A6 = 0.18889 × 10 ⁻⁴ A8 = 0.79656 × 10 ⁻⁵

[Corresponding value of conditional expression (3) of second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00030 y = 0.40ymax… (x-x0) / (N'-N) = 0.00489 y = 0.60ymax… (x-x0) / (N'-N) = 0.02592 y = 0.80ymax … (X-x0) / (N'-N) = 0.08957 y = 1.00ymax… (x-x0) / (N'-N) = 0.25359

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00010 y = 0.40ymax… (x-x0) / (N'-N) =-0.00101 y = 0.60ymax… (x-x0) / (N'-N) =-0.00011 y = 0.80ymax ... (x-x0) / (N'-N) = 0.02373 y = 1.00ymax ... (xx-0) / (N'-N) = 0.
14164

[Corresponding value of conditional expression (3) on the tenth surface (r10)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00085 y = 0.40ymax ... (x-x0) / (N'-N) =-0.01389 y = 0.60ymax ... (x-x0) / (N'-N) =-0.07387 y = 0.80ymax… (x-x0) / (N'-N) =-0.25938 y = 1.00ymax… (x-x0) / (N'-N) =-0.75699

[0082]

[Aspherical surface data of first surface (r1)] ε = 1.0000 A4 = 0.18968 × 10 ⁻² A6 = −0.17409 × 10 ^-3 A8 = 0.58303 × 10 ^-5

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = −0.14087 × 10 ⁻² A6 = −0.26121 × 10 ⁻³ A8 = −0.46363 × 10 ⁻⁴

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = 0.41700 × 10 ^-4 A6 = 0.65832 × 10 ^-4 A8 = 0.10742 × 10 ^-5

[Aspherical surface data of the tenth surface (r10)] ε = 1.0000 A4 = 0.25448 × 10 ⁻² A6 = 0.68837 × 10 ⁻⁴ A8 = 0.44660 × 10 ⁻⁵

[Corresponding value of conditional expression (3) for first surface (r1)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00060 y = 0.40ymax… (x-x0) / (N'-N) = 0.00851 y = 0.60ymax… (x-x0) / (N'-N) = 0.03524 y = 0.80ymax … (X-x0) / (N'-N) = 0.08372 y = 1.00ymax… (x-x0) / (N'-N) = 0.14712

[Corresponding value of conditional expression (3) for second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00015 y = 0.40ymax… (x-x0) / (N'-N) = 0.00283 y = 0.60ymax… (x-x0) / (N'-N) = 0.01833 y = 0.80ymax … (X-x0) / (N'-N) = 0.08130 y = 1.00ymax… (x-x0) / (N'-N) = 0.29579

[Corresponding value of conditional expression (3) on ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00003 y = 0.40ymax… (x-x0) / (N'-N) = 0.00116 y = 0.60ymax… (x-x0) / (N'-N) = 0.01181 y = 0.80ymax … (X-x0) / (N'-N) = 0.06574 y = 1.00ymax… (x-x0) / (N'-N) = 0.25899

[Corresponding value of conditional expression (3) on the tenth surface (r10)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00092 y = 0.40ymax… (x-x0) / (N'-N) =-0.01529 y = 0.60ymax… (x-x0) / (N'-N) =-0.08330 y = 0.80ymax… (x-x0) / (N'-N) =-0.29574 y = 1.00ymax… (x-x0) / (N'-N) =-0.85079

[0091]

[Aspherical surface data of first surface (r1)] ε = 1.0000 A4 = 0.26468 × 10 ⁻² A6 = −0.17738 × 10 ⁻³ A8 = 0.46293 × 10 ⁻⁵

[Aspherical surface data of second surface (r2)] ε = 1.0000 A4 = −0.10075 × 10 ⁻³ A6 = −0.58352 × 10 ⁻⁴ A8 = −0.54769 × 10 ⁻⁴

[Aspherical surface data of ninth surface (r9)] ε = 1.0000 A4 = −0.53743 × 10 ⁻³ A6 = 0.11163 × 10 ⁻³ A8 = 0.43934 × 10 ⁻⁶

[Aspherical surface data of the tenth surface (r10)] ε = 1.0000 A4 = 0.15771 × 10 ⁻² A6 = 0.11216 × 10 ⁻³ A8 = 0.52257 × 10 ⁻⁵

[Corresponding value of conditional expression (3) on first surface (r1)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00125 y = 0.40ymax… (x-x0) / (N'-N) = 0.01806 y = 0.60ymax… (x-x0) / (N'-N) = 0.07667 y = 0.80ymax … (X-x0) / (N'-N) = 0.18952 y = 1.00ymax… (x-x0) / (N'-N) = 0.34943

[Corresponding value of conditional expression (3) for second surface (r2)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) = 0.00002 y = 0.40ymax… (x-x0) / (N'-N) = 0.00051 y = 0.60ymax… (x-x0) / (N'-N) = 0.00640 y = 0.80ymax … (X-x0) / (N'-N) = 0.04913 y = 1.00ymax… (x-x0) / (N'-N) = 0.26096

[Corresponding value of conditional expression (3) on the ninth surface (r9)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00020 y = 0.40ymax… (x-x0) / (N'-N) =-0.00220 y = 0.60ymax… (x-x0) / (N'-N) =-0.00194 y = 0.80ymax… (x-x0) / (N'-N) = 0.03541 y = 1.00ymax… (x-x0) / (N'-N) = 0.22053

[Corresponding value of conditional expression (3) on the tenth surface (r10)] y = 0.00ymax ... (x-x0) / (N'-N) = 0.00000 y = 0.20ymax ... (x-x0) / (N'-N) =-0.00058 y = 0.40ymax… (x-x0) / (N'-N) =-0.01021 y = 0.60ymax ... (x-x0) / (N'-N) =-0.06054 y = 0.80ymax… (x-x0) / (N'-N) =-0.23806 y = 1.00ymax… (x-x0) / (N'-N) =-0.75937

[0100]

[Table 1]

[0101]

As described above, according to the present invention, it is possible to realize a low-cost and compact photographing lens system having good optical performance. Further, if the present invention is applied to a photographing lens system of a digital camera, it is possible to contribute to a higher function, a smaller size and a lower cost of the digital camera.

[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 a lens configuration diagram of a fifth embodiment (Example 5).

FIG. 6 is a lens configuration diagram of a sixth embodiment (Example 6).

FIG. 7 is a lens configuration diagram of a seventh embodiment (Example 7).

FIG. 8 is a lens configuration diagram of an eighth embodiment (Example 8).

FIG. 9 is an aberration diagram of the first embodiment.

FIG. 10 is an aberration diagram of the second embodiment.

FIG. 11 is an aberration diagram of the third embodiment.

FIG. 12 is an aberration diagram of the fourth embodiment.

FIG. 13 is an aberration diagram of the fifth embodiment.

FIG. 14 is an aberration diagram of the sixth embodiment.

FIG. 15 is an aberration diagram of the seventh embodiment.

FIG. 16 is an aberration diagram of the eighth embodiment.

[Explanation of symbols]

 F: Front group A: Aperture R: Rear group LPF: Low-pass filter

Claims (9)

[Claims] 1. A photographing lens system including a front group, an aperture, and a rear group in order from the object side, wherein the front group includes, in order from the object side, a negative lens made of a plastic material, and glass. A rear lens having a positive lens made of a plastic material on the most image side, and including only a lens made of a glass material on the object side of the positive lens, | F × fa / Ha ² + f × fb / Hb ² | <5, where f is the focal length of the entire system, and fa is the plastic in the front group. Fb: focal length of the positive lens made of plastic material in the rear group, Ha: incident height of the on-axis F-number ray on the negative lens made of plastic material in the front group, Hb : Made of plastic material in rear group Axial F-number light incident height of the lens. 2. The photographing lens system according to claim 1, further satisfying the following conditional expression: 0.01 <f / fF <0.91 where fF is a focal length of the front group. 3. An optical axis vertical height satisfying 0.7ymax <y <1.0ymax, where at least one surface of the negative lens in the front group is an aspheric surface and a maximum effective radius of the aspheric surface is ymax. y
2. The photographing lens system according to claim 1, wherein the following conditional expression is satisfied: 0.01 <| (x-x0) / (N'-N) | <2.0, where x: aspherical surface Amount of displacement in the optical axis direction at a height perpendicular to the optical axis (mm; object side direction is negative), x0: Height of the aspherical reference sphere perpendicular to the optical axis , The displacement in the direction of the optical axis (mm; the direction on the object side is negative), N: the refractive index of the medium closer to the object side than the aspherical surface, and N ': the refractive index of the medium closer to the image side than the aspherical surface. The refractive index is 4. At least one surface of the most image-side positive lens in the rear group is an aspheric surface, and the maximum effective radius of the aspheric surface is ym.
2. The photographing lens system according to claim 1, wherein, when ax is satisfied, the following conditional expression is satisfied for an arbitrary height y in the vertical direction of the optical axis such that 0.7ymax <y <1.0ymax. (x-x0) / (N'-N) | <2.0 where x: displacement in the optical axis direction at a height perpendicular to the optical axis of the aspherical surface (mm; negative in the object side direction) ), X0: Displacement in the optical axis direction at a height perpendicular to the optical axis of the aspherical reference sphere (mm; the object side direction is negative), N: Object side of the aspheric surface The refractive index for the d-line of the medium, N ': the refractive index for the d-line of the medium on the image side of the aspherical surface. 5. The photographing apparatus according to claim 1, wherein the rear group includes, in order from the object side, a cemented lens of a biconcave lens and a biconvex lens, and a positive lens made of a plastic material. Lens system. 6. The image pickup apparatus according to claim 1, wherein the rear group includes, in order from the object side, a cemented lens of a biconvex lens and a biconcave lens, and a positive lens made of a plastic material. Lens system. 7. The taking lens system according to claim 5, wherein the cemented lens in the rear group satisfies the following conditional expression: -0.05 <f / fS <0.25, where fS : Focal length of the cemented lens in the rear group. 8. The taking lens system according to claim 5, wherein the most image-side positive lens in the rear group satisfies the following conditional expression: 0.23 <f / fP <0.99. Where fP is the focal length of the positive lens closest to the image in the rear group. 9. The photographing lens system according to claim 1, further satisfying the following conditional expression: 1 <img × R <15, where img: maximum image height, R: The effective diameter of the surface closest to the image.