JPH116958A - Zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens of high magnification composed of a small number of lenses. SOLUTION: In a zoom lens composed, in order from the object side, of a first group Gr1 having a positive power, a second group Gr2 having a negative power and a third group Gr3 having a positive power and performing the power variation by changing an interval between the respective groups, at the time of varying the power from the wide-angle end to the telescopic end, the first group Gr1, is moved to the object side, the second group is fixed. the third group is moved monotonously to the object side and the following conditional relation is satisfied; 0.2<M1 /Z<3.0, where, M1 is a moving amount of the first group at the time of varying the power from the wide-angle end to the telescopic end, Z is the variable power ratio (ft T/fW), fW: the focal distance of the whole system at the telescopic end and fW: the focal distance of the whole system at the wide-angle end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens, and more particularly to a high-magnification zoom lens having an optical structure suitable for a video camera or a television camera and having a small number of lenses.

[0002]

2. Description of the Related Art In recent years, there has been a demand for downsizing and cost reduction of video cameras and television cameras, and accordingly, there has been a demand for downsizing and cost reduction of photographic lens systems. On the other hand, a higher specification is required, and a zoom lens with higher magnification is required for a photographing lens system. Although miniaturization, cost reduction, and high magnification of the optical system are contradictory, various improvements have been made to the zoom lens in order to meet these demands.

[0003] For example, as a zoom type aiming at miniaturization, cost reduction and high magnification of a lens system, a positive first lens group, a negative second lens group, and a positive third lens are arranged in order from the object side. There are three-component zoom types composed of groups, and are disclosed in JP-A-2-56515, JP-A-4-281419, and JP-A-5-281419.
203875 and the like.

[0004]

However, in any of the above proposals, the total length of the lens system and the number of lenses are limited.
The fact is that there is still room for improvement. Also, a lens having a small number of lenses has been proposed, but the zoom ratio is 2 to 2.
It is only three times and cannot meet the required specifications. The present invention has been made in view of such a situation, and an object of the present invention is to provide a zoom lens that can be configured with a small number of lenses and that can achieve high magnification zoom.

[0005]

In order to achieve the above object, according to the present invention, in order from the object side, a first unit having a positive power, a second unit having a negative power, and a positive unit are provided. A zoom lens that performs zooming by changing the distance between the groups, when zooming from the wide-angle end to the telephoto end, the first group moves to the object side, The second group is fixed, and the third group is a zoom lens that moves monotonously to the object side, and is configured to satisfy the following conditional expression. 0.2 <M ₁ /Z<3.0

Where, M ₁ : the amount of movement of the first lens unit during zooming from the wide-angle end to the telephoto end Z: zoom ratio (f _T / f _W ) f _T : focal length of the entire system at the telephoto end f _W : focal length of the entire system at the wide-angle end.

Further, it is assumed that the first group and the second group each include two lenses, a negative lens and a positive lens. Alternatively, the first group includes two lenses, a negative lens and a positive lens, and the third group includes a positive lens having a strong convex surface on the object side at the most object side.

Further, as another configuration, in order from the object side,
A first group with positive power and a second group with negative power
In a zoom lens that includes a lens unit and a third lens unit having a positive power and performs zooming by changing the distance between the lens units, when zooming from the wide-angle end to the telephoto end, the first lens unit While moving to the object side, the second lens group moves at least at the intermediate focal length f _M so as to be on the object side from the wide-angle end, and the third lens group moves monotonously to the object side. A zoom lens in which the distance between the first group and the second group is widened and the distance between the second group and the third group is narrow, wherein the zoom lens satisfies the following conditional expression. 0.2 <M ₁ /Z<3.0

Where M ₁ : the amount of movement of the first lens unit from the wide-angle end to the telephoto end when zooming Z: the zoom ratio (f _T / f _W ) f _T : the focal length of the entire system at the telephoto end f _W : focal length of the entire system at the wide-angle end f _M : intermediate focal length (√ (f _W × f _T )).

When zooming from the wide-angle end to the telephoto end,
The second group is configured to move monotonously to the object side. Also,
The first group and the second group are each composed of two lenses, a negative lens and a positive lens. Alternatively, the first group includes two lenses, a negative lens and a positive lens, and the third group includes, on the most object side,
The positive lens has a strong convex surface on the object side.

Further, as another configuration, a first unit having a positive power, a second unit having a negative power, and a third unit having a positive power are arranged in this order from the object side. In a zoom lens that performs zooming by changing the distance between the zoom lens and the zoom lens, when zooming from the wide-angle end to the telephoto end, the first group moves to the object side, and the second group is fixed. The third unit is a zoom lens that moves monotonously to the object side, and has a configuration that satisfies the following conditional expression. 4.0 <f ₁ / f _W <10.0

Where f _{1 is} the focal length of the first lens unit f _{W is} the focal length of the entire system at the wide-angle end.

The first group and the second group are each composed of two lenses, a negative lens and a positive lens. Alternatively, the first group includes two lenses, a negative lens and a positive lens, and the third group includes a positive lens having a strong convex surface on the object side at the most object side.

As another configuration, a first unit having a positive power, a second unit having a negative power, and a third unit having a positive power are arranged in this order from the object side. In a zoom lens that performs zooming by changing the distance, when zooming from the wide-angle end to the telephoto end, the first group moves to the object side, and the second group has at least an intermediate focal length f _M. At some point, the third unit moves monotonously to the object side from the wide-angle end, and the distance between the first unit and the second unit is increased by moving monotonously to the object side. A zoom lens in which an interval between a group and the third group is narrowed, and has a configuration satisfying the following conditional expression.

4.0 <f ₁ / f _W <10.0 where f ₁ : focal length of the first lens unit f _T : focal length of the entire system at the telephoto end f _w : focal length of the entire system at the wide-angle end Distance f _M : Intermediate focal length (√ (f _W × f _T )).

When zooming from the wide-angle end to the telephoto end,
The second group is configured to move monotonously to the object side. Also,
The first group and the second group are each composed of two lenses, a negative lens and a positive lens. Alternatively, the first group includes two lenses, a negative lens and a positive lens, and the third group includes, on the most object side,
The positive lens has a strong convex surface on the object side.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show lens configurations of the lens systems of the first to fifth embodiments, respectively. As shown in these figures, the lens systems of the first to fifth embodiments each include, in order from the object side (left side in the figure), a positive first lens group Gr1 and a negative second lens group Gr.
2, a stop A, and a positive third lens unit Gr3, and a low-pass filter P is provided closest to the image side.

Of these embodiments, in the first, second and fifth embodiments, during zooming from the wide-angle end to the telephoto end, the first lens unit Gr1 moves monotonously to the object side, The second lens group Gr2 is fixed, and the third lens group Gr3 moves monotonously to the object side. In the third and fourth embodiments, when zooming from the wide-angle end to the telephoto end, the first lens group Gr1 moves monotonously to the object side, and the second lens group Gr2
The third lens group Gr3 has moved toward the object side from the wide-angle end at the intermediate focal length f _M , and has moved toward the object side.

Further, at the time of zooming from the wide-angle end to the telephoto end, the distance between the first lens group Gr1 and the second lens group Gr2 is widened, and the distance between the second lens group Gr2 and the third lens group Gr3 is narrow. So that each group is moving. By adopting such a movement form of each lens unit, zooming is effectively performed, and the amount of movement and the overall length of each lens unit during zooming are reduced.

In particular, if the second lens group Gr2 is fixed at the time of zooming, the number of groups to be moved becomes two, so that the lens barrel configuration is simplified and the amount of movement of the first lens group Gr1 is reduced. There is an advantage that can be. Further, when the second lens group Gr2 is moved at the intermediate focal length f _M so as to be located on the object side from the wide angle end, the overall length at the wide angle end can be reduced.

Also, the first lens unit Gr1 of the first embodiment
Consists of, in order from the object side, a cemented negative meniscus lens having a convex surface facing the object side and a biconvex lens having a strong convex surface facing the object side, and the second lens group Gr2 is arranged in order from the object side to the image side. The third lens group Gr3 includes, in order from the object side, a biconvex lens having a strong convex surface facing the object side, and a biconvex lens having a positive meniscus lens having a convex surface facing the image side. And a negative meniscus lens with a convex surface.

The first lens unit Gr1 of the second embodiment
Comprises, in order from the object side, a negative meniscus lens having a convex surface facing the object side, and a biconvex lens having a strong convex surface facing the object side. The second lens group Gr2 has a strong concave surface facing the image side in order from the object side. The third lens group Gr3 includes, in order from the object side, a biconvex lens having a strong convex surface facing the object side and a strong meniscus lens having the convex surface facing the object side. And a bi-concave lens with a concave surface.

Further, the first lens unit Gr1 of the third embodiment
Consists of, in order from the object side, a cemented negative meniscus lens having a convex surface facing the object side and a biconvex lens having a strong convex surface facing the object side, and the second lens group Gr2 is arranged in order from the object side to the image side. A negative meniscus lens having a strong concave surface and a positive meniscus lens having a convex surface facing the image side;
The lens group Gr3 is composed of, in order from the object side, a biconvex lens having a strong convex surface facing the object side and a biconcave lens having a concave surface facing the image side.

The first lens unit Gr1 of the fourth embodiment
Consists of, in order from the object side, a cemented negative meniscus lens having a convex surface facing the object side and a biconvex lens having a strong convex surface facing the object side, and the second lens group Gr2 is arranged in order from the object side to the image side. A negative meniscus lens having a strong concave surface and a positive meniscus lens having a convex surface facing the image side;
The lens group Gr3 is composed of, in order from the object side, a biconvex lens having a strong convex surface facing the object side and a biconcave lens having a concave surface facing the image side.

Further, the first lens unit Gr1 of the fifth embodiment
Consists of, in order from the object side, a cemented negative meniscus lens having a convex surface facing the object side and a biconvex lens having a strong convex surface facing the object side, and the second lens group Gr2 is arranged in order from the object side to the image side. A negative meniscus lens having a strong concave surface and a positive meniscus lens having a convex surface facing the image side;
The lens group Gr3 is composed of, in order from the object side, a biconvex lens having a strong convex surface facing the object side and a biconcave lens having a concave surface facing the image side.

The first lens group Gr1 of each embodiment
Consists of a negative lens and a positive lens,
This is the minimum condition for favorably correcting axial chromatic aberration. The second lens group Gr2 includes a negative lens and a positive lens, which is the minimum condition for favorably correcting lateral chromatic aberration. Further, a positive lens having a strong curvature on the object side is provided closest to the object side of the third lens group Gr3. This is to make the divergent light beam incident on the third lens group Gr3 largely converge immediately after the incidence. Thereby, spherical aberration is favorably corrected.

Each of the above embodiments satisfies the following conditional expressions. 0.2 <M ₁ /Z<3.0 (1) where M _{1 is} the amount of movement of the first lens unit Gr1 during zooming from the wide-angle end to the telephoto end Z: zoom ratio (f _T / f) _W) f _T: the focal length of the entire system at the telephoto end f _W: the focal length of the entire system at the wide-angle end.

The above conditional expression (1) satisfies the first lens group Gr1.
Is a formula that defines the ratio between the moving amount during zooming and the zoom ratio.
This is a condition for balancing the size and performance of the optical system by controlling the amount of movement of the first lens group Gr1 according to the zoom ratio. If the upper limit of conditional expression (1) is exceeded, the amount of movement of the first lens unit Gr1 will be too large with respect to the zoom ratio, causing an increase in the overall length at the telephoto end, and an increase in the front lens diameter. I will invite you.

On the other hand, if the lower limit of conditional expression (1) is exceeded, the amount of movement of the first lens unit Gr1 will be too small with respect to the zoom ratio, and the total length at the wide-angle end will increase. It is necessary to increase the power of the first lens group Gr1 in order to suppress the aberration, and it becomes difficult to correct spherical aberration and axial chromatic aberration at the telephoto end.

Further, all the embodiments satisfy the following conditional expressions. 4.0 <f ₁ / f _W <10.0 (2) where f _{1 is} the focal length of the first lens unit f _{w is} the focal length of the entire system at the wide-angle end.

This stipulates the focal length of the first lens group Gr1, but if the focal length of the first lens group Gr1 becomes too short below the lower limit of the conditional expression (2),
It becomes difficult to correct spherical aberration and lateral chromatic aberration on the telephoto side.
On the contrary, when the value exceeds the upper limit of the conditional expression (2), the first lens unit Gr1
Is too long, the amount of movement of the first lens unit Gr1 at the time of zooming becomes too large, so that compactness on the telephoto side is lost.

It is desirable that the following conditional expression is satisfied. −0.95 <f ₂ / f _W <−2.5 (3) where f _{2 is} the focal length of the second lens unit Gr2, and f _{W is} the focal length of the entire system at the wide-angle end.

The above conditional expression (3) satisfies the second lens unit Gr2.
This is an expression that defines the ratio between the focal length at the wide-angle end and the focal length of the second lens group Gr2. When the value exceeds the upper limit of conditional expression (3), the power of the second lens unit Gr2 becomes too weak, so that the performance is improved. However, the total length of the optical system is increased, and the moving amount during zooming is increased. In addition, the lens diameter for securing the peripheral light amount is increased. As a result, the size of the entire camera becomes large, so that it is impossible to meet the demand for compactness.

On the other hand, if the lower limit of conditional expression (3) is exceeded, the power of the second lens unit Gr2 becomes too strong, so that the moving distance and the overall length during zooming become small, which is advantageous for miniaturization. However, various aberrations are remarkably deteriorated. Especially,
As the image plane falls significantly on the over side, negative distortion becomes worse.

When an aspherical surface is provided in the second lens unit Gr2, there is an effect particularly on field curvature and distortion. In this case, at least one aspherical surface satisfies the following conditional expression (4). −0.8 <(| X | − | X ₀ |) / C _O (N′−N) f ₂ <0.0 (4) where X is the effective optical path diameter represented by the following equation (a). Displacement in the optical axis direction at the height Y X _O : Displacement in the optical axis direction at the height Y of the effective optical path diameter represented by the following equation (b) C _O : Curvature of the spherical surface N ′ as the reference of the aspheric surface : Refractive index on the image side of the aspherical surface N: Refractive index on the object side of the aspherical surface f ₂ : Focal length of the second lens group.

[0036] In this _{case, X = X O + ΣA j} Y j ····· (a) X O = C O Y 2/1 + (1-εC O 2 Y 2) 1/2 ····· (b ) Where A _j : j-order aspherical coefficient ε: secondary curvature parameter

The above conditional expression (4) means that the aspherical surface has a shape that weakens the negative power of the second lens unit Gr2. If the lower limit of conditional expression (4) is exceeded, the negative power becomes too weak, so that the underside of the field curvature at the wide-angle end becomes large, and the positive distortion becomes remarkable. On the other hand, if the upper limit of conditional expression (4) is exceeded, the effect of weakening the negative power is small, and there is no merit of using the aspheric surface of the second lens unit Gr2. As the side tilt increases, negative distortion becomes significant.

In the case where an aspherical surface is provided in the third lens unit Gr3, it is particularly effective for spherical aberration. In this case, at least one aspherical surface satisfies the following conditional expression (5). −1.0 <(| X | − | X ₀ |) / C _O (N′−N) f ₃ <1.0 (5) where f ₃ is the focal length of the third lens group.

If the lower limit value of conditional expression (5) is exceeded, the positive power in the peripheral portion becomes too weak, and the tendency of spherical aberration to become excessive becomes significant. On the other hand, when the value exceeds the upper limit, the positive power in the peripheral portion becomes too strong, and the under tendency of the spherical aberration becomes remarkable.

Hereinafter, the structure of the zoom lens according to the present invention will be described more specifically with reference to construction data and aberration diagrams. Examples 1 to 5 described below correspond to the above-described first to fifth embodiments, respectively. The lens configuration diagrams (FIGS. 1 to 5) representing the first to fifth embodiments are as follows.
The corresponding lens configurations of Examples 1 to 5 are shown.

In each embodiment, ri (i = 1, 2, 3,...) Indicates 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 ...) Is the refractive index for the d-line of the i-th lens counted from the object side,
Indicates Abbe number. In each of the examples, the surface marked with an asterisk (*) indicates that the surface is constituted by an aspherical surface, and the expression representing the surface shape of the aspherical surface is the expression described in conditional expression (4). It is.

<< Embodiment 1 >>

[Aspherical surface coefficient of fourth surface (r4)] ε = 1.0000 A4 = 0.43211 × 10 ^-2 A6 = -0.26499 × 10 ^-2 A8 = 0.85892 × 10 ^-3 A10 = -0.13129 × 10 ^-3 A12 = 0.86344 × 10 ^-5

[Aspherical surface coefficient of fifth surface (r5)] ε = 1.0000 A4 = -0.99900 × 10 ^-2 A6 = -0.29443 × 10 ^-2 A8 = -0.90977 × 10 ^-3 A10 = 0.39506 × 10 ^-3 A12 = -0.71124 × 10 ^-4

[Aspherical surface coefficient of the ninth surface (r9)] ε = 1.0000 A4 = -0.90209 × 10 ^-2 A6 = 0.41064 × 10 ^-3 A8 = -0.29246 × 10 ^-2 A10 = 0.13103 × 10 ^-2 A12 = -0.28195 × 10 ^-3

[Aspherical surface coefficient of the eleventh surface (r11)] ε = 1.0000 A4 = 0.73187 × 10 ^-2 A6 = 0.21358 × 10 ^-2 A8 = -0.30599 × 10 ^-3 A10 = -0.12063 × 10 ^-2 A12 = 0.53304 × 10 ^-3

[Aspherical surface coefficient of the twelfth surface (r12)] ε = 1.0000 A4 = 0.28827 × 10 ⁻¹ A6 = 0.10287 × 10 ⁻¹ A8 = -0.97538 × 10 ^-3 A10 = -0.16814 × 10 ⁻² A12 = 0.18718 × 10 ^-2

[Corresponding value of conditional expression (4) on the fourth surface (r4)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00003 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) · f2} =-0.00041 y = 0.30ymax… {| x |-| x0 |} / {C0 · (N'-N) · f2} =-0.00186 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00502 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.01011 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.01694 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.02546 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03672 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.05361 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.08185

[Corresponding value of conditional expression (4) on the fifth surface (r5)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) · f2} =-0.00008 y = 0.30ymax… {| x |-| x0 |} / {C0 · (N'-N) · f2} =-0.00042 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00140 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00368 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00829 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.01687 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03179 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.05654 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.09642

[Corresponding value of conditional expression (5) on ninth surface (r9)] y = 0.00ymax... {| X |-| x0 |} / {C0 · (N′−N) · f3} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00004 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00020 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00063 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00156 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00336 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00655 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01192 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.02067 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.03463

[Corresponding value of conditional expression (5) on eleventh surface (r11)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00001 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N'- N) ・ f3} = 0.00024 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00122 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00395 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00989 y = 0.60ymax… { | x |-| x0 |} / {C0 · (N'-N) · f3} = 0.02104 y = 0.70ymax… {| x |-| x0 |} / {C0 · (N'-N) · f3} = 0.03983 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.06890 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ ( N'-N) · f3} = 0.11081 y = 1.00ymax… {| x |-| x0 |} / {C0 · (N'-N) · f3} = 0.16841

[Corresponding value of conditional expression (5) on twelfth surface (r12)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = − 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.00005 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00027 y = 0.40ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00087 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00217 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00464 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.00889 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01572 y = 0.90ymax… {| x |- | x0 |} / {C0 · (N'-N) · f3} =-0.02621 y = 1.00ymax ｛| x | − | x0 |｝ / ｛C0 ·
(N′−N) · f3｝ = − 0.04179

<< Embodiment 2 >>

[Aspherical surface coefficient of fourth surface (r4)] ε = 1.0000 A4 = 0.35558 × 10 ^-2 A6 = -0.19282 × 10 ^-2 A8 = 0.58717 × 10 ^-3 A10 = -0.69677 × 10 ^-4 A12 = 0.24236 × 10 ^-5

[Aspherical surface coefficient of fifth surface (r5)] ε = 1.0000 A4 = -0.10687 × 10 ⁻¹ A6 = −0.13290 × 10 ⁻² A8 = -0.20252 × 10 ⁻² A10 = 0.97516 × 10 ^-3 A12 = -0.17463 × 10 ^-3

[Aspherical surface coefficient of the ninth surface (r9)] ε = 1.0000 A4 = -0.86322 × 10 ^-2 A6 = 0.25268 × 10 ^-2 A8 = -0.43939 × 10 ^-2 A10 = 0.18136 × 10 ^-2 A12 = -0.32438 × 10 ^-3

[Aspherical surface coefficient of the eleventh surface (r11)] ε = 1.0000 A4 = 0.14049 × 10 ⁻¹ A6 = 0.15318 × 10 ⁻² A8 = −0.16627 × 10 ^-3 A10 = −0.68691 × 10 ^-3 A12 = 0.30468 × 10 ^-3

[Aspherical surface coefficient of the twelfth surface (r12)] ε = 1.0000 A4 = 0.30477 × 10 ⁻¹ A6 = 0.11214 × 10 ⁻¹ A8 = −0.667234 × 10 ⁻² A10 = 0.40279 × 10 ⁻² A12 = − 0.39886 × 10 ^-3

[Corresponding value of conditional expression (4) on fourth surface (r4)] y = 0.00ymax... {| X |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00002 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) · f2} =-0.00036 y = 0.30ymax… {| x |-| x0 |} / {C0 · (N'-N) · f2} =-0.00165 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00453 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00934 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.01623 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.02579 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.04000 y = 0.90ymax… {| x |-| x0 |} / {C0 · (N′-N) · f2} =-0.06255 y = 1.00ymax ｛| x | − | x0 |｝ / ｛C0 ·
(N′−N) · f2｝ = − 0.09737

[Corresponding value of conditional expression (4) on fifth surface (r5)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00001 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) · f2} =-0.00008 y = 0.30ymax… {| x |-| x0 |} / {C0 · (N'-N) · f2} =-0.00044 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00144 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00370 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00822 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.01647 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03054 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.05345 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.09033

[Corresponding value of conditional expression (5) on ninth surface (r9)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00006 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00030 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00093 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00231 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00498 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00990 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01849 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.03308 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.05811

[Corresponding value of conditional expression (5) on eleventh surface (r11)] y = 0.00ymax ... {| x |-| x0 |} / {C0. (N'-N) .f3} =-0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00003 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} = 0.00055 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00279 y = 0.40ymax… {| x |-| x0 | } / {C0 ・ (N'-N) ・ f3} = 0.00892 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.02206 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.04632 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3 } = 0.08669 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.10224 y = 0.90ymax… {| x |-| x0 |} / {C0 ・(N'-N) · f3} = 0.07801 y = 1.00ymax… {| x |-| x0 |} / {C0 · (N'-N) · f3} = 0.02183

[Corresponding value of conditional expression (5) on twelfth surface (r12)] y = 0.00ymax ... {| x |-| x0 |} / {C0. (N'-N) .f3} =-0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00001 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.00013 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00065 y = 0.40ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00210 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00529 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01131 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.02167 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.03836 y = 0.90ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.06418 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.10331

<< Embodiment 3 >>

[Aspherical surface coefficient of the fourth surface (r4)] ε = 1.0000 A4 = 0.38104 × 10 ^-2 A6 = -0.19863 × 10 ^-2 A8 = 0.58725 × 10 ^-3 A10 = -0.69676 × 10 ^-4 A12 = 0.24236 × 10 ^-5

[Aspherical surface coefficient of fifth surface (r5)] ε = 1.0000 A4 = -0.10488 × 10 ^-1 A6 = -0.13654 × 10 ^-2 A8 = -0.20255 × 10 ^-2 A10 = 0.97516 × 10 ^-3 A12 = -0.17463 × 10 ^-3

[Aspherical surface coefficient of the ninth surface (r9)] ε = 1.0000 A4 = −0.88749 × 10 ⁻² A6 = 0.25363 × 10 ⁻² A8 = −0.43935 × 10 ⁻² A10 = 0.18136 × 10 ⁻² A12 = -0.32438 × 10 ^-3

[Aspherical surface coefficient of the eleventh surface (r11)] ε = 1.0000 A4 = 0.14049 × 10 ⁻¹ A6 = 0.15318 × 10 ⁻² A8 = −0.16627 × 10 ^-3 A10 = −0.68691 × 10 ^-3 A12 = 0.30468 × 10 ^-3

[Aspherical surface coefficient of the twelfth surface (r12)] ε = 1.0000 A4 = 0.30477 × 10 ⁻¹ A6 = 0.11214 × 10 ⁻¹ A8 = −0.667234 × 10 ⁻² A10 = 0.40279 × 10 ⁻² A12 = − 0.39886 × 10 ^-3

[Corresponding value of conditional expression (4) on fourth surface (r4)] y = 0.00ymax... {| X |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00002 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) · f2} =-0.00032 y = 0.30ymax… {| x |-| x0 |} / {C0 · (N'-N) · f2} =-0.00149 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00417 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00875 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.01538 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.02434 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03669 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.05474 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.08161

[Corresponding value of conditional expression (4) on fifth surface (r5)] y = 0.00ymax... {| X |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.00006 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00033 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00109 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00278 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00613 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.01219 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.02249 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03908 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.06508

[Corresponding value of conditional expression (5) on ninth surface (r9)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00007 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00033 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00103 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00255 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00552 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.01095 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.02045 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.03657 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.06435

[Corresponding value of conditional expression (5) on eleventh surface (r11)] y = 0.00ymax ... {| x |-| x0 |} / {C0. (N'-N) .f3} =-0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00005 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} = 0.00081 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00413 y = 0.40ymax… {| x |-| x0 | } / {C0 ・ (N'-N) ・ f3} = 0.01320 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.03265 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.06854 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3 } = 0.07688 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.04772 y = 0.90ymax… {| x |-| x0 |} / {C0 ・(N'-N) · f3} =-0.01574 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.13082

[Corresponding value of conditional expression (5) on twelfth surface (r12)] y = 0.00ymax ... {| x |-| x0 |} / {C0. (N'-N) .f3} =-0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00001 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.00014 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00075 y = 0.40ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00242 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00608 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01303 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.02497 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.04426 y = 0.90ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.07417 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.11969

<< Embodiment 4 >>

[Aspherical surface coefficient of the fourth surface (r4)] ε = 1.0000 A4 = 0.49606 × 10 ^-2 A6 = -0.18679 × 10 ^-2 A8 = 0.18135 × 10 ^-3 A10 = 0.25065 × 10 ^-4 A12 =- 0.34002 × 10 ^-5

[Aspherical surface coefficient of fifth surface (r5)] ε = 1.0000 A4 = −0.53884 × 10 ⁻² A6 = −0.12523 × 10 ⁻² A8 = −0.16825 × 10 ⁻² A10 = 0.25510 × 10 ⁻³ A12 = 0.12877 × 10 ^-4

[Aspherical surface coefficient of the ninth surface (r9)] ε = 1.0000 A4 = -0.74090 × 10 ^-2 A6 = 0.36776 × 10 ^-2 A8 = -0.45738 × 10 ^-2 A10 = 0.17594 × 10 ^-2 A12 = -0.28578 × 10 ^-3

[Aspherical surface coefficient of the eleventh surface (r11)] ε = 1.0000 A4 = 0.12523 × 10 ^-1 A6 = 0.65982 × 10 ^-3 A8 = -0.57961 × 10 ^-3 A10 = -0.24606 × 10 ^-3 A12 = 0.99508 × 10 ^-4

[Aspherical surface coefficient of twelfth surface (r12)] ε = 1.0000 A4 = 0.29975 × 10 ⁻¹ A6 = 0.10943 × 10 ⁻¹ A8 = −0.53112 × 10 ⁻² A10 = 0.22484 × 10 ⁻² A12 = 0.94187 × 10 ^-4

[Corresponding Value of Conditional Expression (4) of Fourth Surface (r4)] y = 0.00ymax... {| X |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00007 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.00110 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00513 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.01437 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.02982 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.05023 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.07253 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.09448 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.12001 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.16480

[Corresponding Value of Conditional Expression (4) on Fifth Surface (r5)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) · f2} =-0.00005 y = 0.30ymax… {| x |-| x0 |} / {C0 · (N'-N) · f2} =-0.00025 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00086 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00231 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00546 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.01183 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.02389 y = 0.90ymax… {| x |-| x0 |} / {C0 · (N′-N) · f2} =-0.04527 y = 1.00ymax ｛| x | − | x0 |｝ / ｛C0 ·
(N′−N) · f2｝ = − 0.08030

[Corresponding value of conditional expression (5) on ninth surface (r9)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00006 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00030 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00092 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00223 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00477 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00950 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01790 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.03250 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.05877

[Corresponding value of conditional expression (5) on eleventh surface (r11)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = − 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00003 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} = 0.00051 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00259 y = 0.40ymax… {| x |-| x0 | } / {C0 ・ (N'-N) ・ f3} = 0.00823 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.02013 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.04165 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3 } = 0.07644 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.12789 y = 0.90ymax… {| x |-| x0 |} / {C0 ・(N'-N) · f3} = 0.15195 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.14304

[Corresponding value of conditional expression (5) on twelfth surface (r12)] y = 0.00ymax ... {| x |-| x0 |} / {C0. (N'-N) .f3} =-0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00001 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.00020 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00106 y = 0.40ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00344 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00866 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01859 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.03571 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.06336 y = 0.90ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.10621 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.17146

<< Embodiment 5 >>

[Aspherical surface coefficient of fourth surface (r4)] ε = 1.0000 A4 = 0.70975 × 10 ^-2 A6 = -0.33106 × 10 ^-2 A8 = 0.90948 × 10 ^-3 A10 = -0.91009 × 10 ^-4 A12 = 0.15581 × 10 ^-5

[Aspherical surface coefficient of fifth surface (r5)] ε = 1.0000 A4 = -0.50268 × 10 ^-2 A6 = -0.22635 × 10 ^-2 A8 = -0.20490 × 10 ^-2 A10 = 0.12188 × 10 ^-2 A12 = -0.20492 × 10 ^-3

[Aspherical surface coefficient of ninth surface (r9)] ε = 1.0000 A4 = −0.67922 × 10 ⁻² A6 = 0.43760 × 10 ⁻² A8 = −0.47283 × 10 ⁻² A10 = 0.17022 × 10 ⁻² A12 = -0.28605 × 10 ^-3

[Aspherical surface coefficient of the eleventh surface (r11)] ε = 1.0000 A4 = 0.89966 × 10 ⁻² A6 = 0.96879 × 10 ⁻³ A8 = 0.28150 × 10 ⁻³ A10 = −0.60519 × 10 ⁻³ A12 = 0.27835 × 10 ^-3

[Aspherical surface coefficient of the twelfth surface (r12)] ε = 1.0000 A4 = 0.23388 × 10 ^-1 A6 = 0.12923 × 10 ^-1 A8 = -0.90422 × 10 ^-2 A10 = 0.48878 × 10 ^-2 A12 =- 0.39886 × 10 ^-3

[Corresponding value of conditional expression (4) on fourth surface (r4)] y = 0.00ymax... {| X |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00004 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ 2} =-0.00065 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00302 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00850 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.01805 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03222 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.05194 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.07987 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.12147 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.18339

[Corresponding value of conditional expression (4) on fifth surface (r5)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f2} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.00004 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00023 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00081 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00225 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.00534 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f2} =-0.01129 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.02170 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.03845 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f2} =-0.06450

[Corresponding value of conditional expression (5) on ninth surface (r9)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′−N) · f3} = 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00006 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00027 y = 0.40ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00082 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00195 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00416 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} =-0.00841 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.01642 y = 0.90ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.03165 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.06258

[Corresponding value of conditional expression (5) for eleventh surface (r11)] y = 0.00ymax ... {| x |-| x0 |} / {C0. (N'-N) .f3} =-0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00000 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N ' -N) ・ f3} = 0.00004 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00022 y = 0.40ymax… {| x |-| x0 | } / {C0 · (N'-N) · f3} = 0.00069 y = 0.50ymax… {| x |-| x0 |} / {C0 · (N'-N) · f3} = 0.00172 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.00364 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3 } = 0.00689 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} = 0.01201 y = 0.90ymax… {| x |-| x0 |} / {C0 ・(N'-N) · f3} = 0.01984 y = 1.00ymax… {| x |-| x0 |} / {C0 · (N'-N) · f3} = 0.03196

[Corresponding value of conditional expression (5) for twelfth surface (r12)] y = 0.00ymax ... {| x |-| x0 |} / {C0 · (N′-N) · f3} = − 0.00000 y = 0.10ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00009 y = 0.20ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.00144 y = 0.30ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.00755 y = 0.40ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.02480 y = 0.50ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.06314 y = 0.60ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.13663 y = 0.70ymax… {| x |-| x0 |} / {C0 ・ (N '-N) ・ f3} =-0.26441 y = 0.80ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-0.47298 y = 0.90ymax… {| x |- | x0 |} / {C0 ・ (N'-N) ・ f3} =-0.80228 y = 1.00ymax… {| x |-| x0 |} / {C0 ・ (N'-N) ・ f3} =-1.31900

FIGS. 6 to 10 are aberration diagrams corresponding to the first to fifth embodiments, respectively. In each of FIGS. 6 to 10, the upper part shows the wide-angle end, the middle part shows the intermediate focal length, and the lower part shows the telephoto end. ing. And in the spherical aberration diagram, the solid line
(d) represents the d-line, and the dashed line (sc) represents the sine condition.
In the astigmatism diagram, the solid line (DS) and the broken line (D
M) represents astigmatism of the sagittal light beam and the meridional light beam, respectively. Table 1 shows values corresponding to the conditional expressions (1) to (5) in Examples 1 to 5.

[0098]

[Table 1]

Note that each lens group is as described above.
It is not necessary to consist only of a refraction lens that deflects an incident light beam by refraction, but a diffractive lens that deflects an incident light beam by diffraction or a refraction-diffraction hybrid type that deflects an incident light beam by combining diffraction and refraction. A form including a lens or the like may be used.

[0100]

As described above, according to the present invention,
By configuring with a small number of lenses, it is possible to provide a zoom lens that can be reduced in cost and that can achieve high magnification zoom.

[Brief description of the drawings]

FIG. 1 is a lens configuration diagram according to a first embodiment of the present invention.

FIG. 2 is a lens configuration diagram according to a second embodiment of the present invention.

FIG. 3 is a lens configuration diagram according to a third embodiment of the present invention.

FIG. 4 is a lens configuration diagram according to a fourth embodiment of the present invention.

FIG. 5 is a lens configuration diagram according to a fifth embodiment of the present invention.

FIG. 6 is an aberration diagram of the first embodiment of the present invention.

FIG. 7 is an aberration diagram of the second embodiment of the present invention.

FIG. 8 is an aberration diagram of the third embodiment of the present invention.

FIG. 9 is an aberration diagram of the fourth embodiment of the present invention.

FIG. 10 is an aberration diagram of a fifth embodiment of the present invention.

[Explanation of symbols]

 Gr1 First lens group Gr2 Second lens group Gr3 Third lens group A Aperture P Low-pass filter

Claims (14)

[Claims] 1. A first group having a positive power, a second group having a negative power, and a third group having a positive power are arranged in order from the object side, and an interval between the groups is changed. When performing zooming from the wide-angle end to the telephoto end, the first unit moves to the object side, the second unit is fixed, and the third unit is an object. A zoom lens that moves monotonously to the side, and satisfies the following conditional expression: 0.2 <M ₁ /Z<3.0, where M ₁ : wide-angle end of the first lens unit amount of movement during zooming to the telephoto end from Z: zoom ratio _{(f T / f W) f} T: the focal length of the entire system at the telephoto end f _W: is the focal length of the entire system at the wide-angle end . 2. The zoom lens according to claim 1, wherein the first group and the second group each include two lenses, a negative lens and a positive lens. 3. The first group includes a negative lens and a positive lens.
2. The zoom lens according to claim 1, wherein the third unit includes a positive lens having a strong convex surface on the object side at the most object side thereof. 3. 4. A first lens unit having a positive power, a second lens unit having a negative power, and a third lens unit having a positive power are arranged in order from the object side. When zooming from the wide-angle end to the telephoto end, the first lens unit moves to the object side, and the second lens unit moves at least when the intermediate focal length f _M is reached. The third group moves monotonically to the object side from the wide-angle end, and the distance between the first group and the second group increases by moving monotonously to the object side. A zoom lens having a smaller distance from the third lens group, wherein the following conditional expression is satisfied: 0.2 <M ₁ /Z<3.0, where M ₁ : first lens group at the telephoto end: the amount of movement during zooming from the wide angle end to the telephoto end Z: zoom ratio _{(f T / f W) f} T F _W : focal length of the entire system at the wide-angle end f _M : intermediate focal length (√ (f _W × f _T )). 5. The zoom lens system according to claim 4, wherein when zooming from the wide-angle end to the telephoto end, the second lens unit moves monotonously to the object side.
A zoom lens according to claim 1. 6. The zoom lens according to claim 4, wherein the first group and the second group each include two lenses, a negative lens and a positive lens. 7. The first group includes a negative lens and a positive lens.
5. The zoom lens according to claim 4, wherein the third group includes a positive lens having a strong convex surface on the object side at the most object side thereof. 6. 8. A first group having a positive power, a second group having a negative power, and a third group having a positive power are arranged in order from the object side, and an interval between the groups is changed. When performing zooming from the wide-angle end to the telephoto end, the first unit moves to the object side, the second unit is fixed, and the third unit is an object. A zoom lens that moves monotonously to the side and satisfies the following conditional expression: 4.0 <f ₁ / f _W <10.0, where f ₁ : focal point of the first lens unit Distance f _W : Focal length of the entire system at the wide-angle end. 9. The zoom lens according to claim 8, wherein the first group and the second group each include two lenses, a negative lens and a positive lens. 10. The first group is composed of two lenses, a negative lens and a positive lens, and the third group has a positive lens having a strong convex surface on the object side at the most object side. The zoom lens according to claim 8, wherein: 11. A first group having a positive power, a second group having a negative power, and a third group having a positive power are arranged in order from the object side, and an interval between the groups is changed. When zooming from the wide-angle end to the telephoto end, the first lens unit moves to the object side, and the second lens unit moves at least when the intermediate focal length f _M is reached. The third group moves monotonically to the object side from the wide-angle end, and the distance between the first group and the second group increases by moving monotonously to the object side. A zoom lens having a smaller distance from the third lens group, wherein the following conditional expression is satisfied: 4.0 <f ₁ / f _W <10.0, where f ₁ : first the focus of the group length f _T: the focal length f _W of the entire system at the telephoto end focal length of the entire system at the wide-angle end f _M : intermediate focal length (√ (f _W × f _T )). 12. The zoom lens according to claim 11, wherein when zooming from the wide-angle end to the telephoto end, the second lens unit moves monotonously to the object side. 13. The zoom lens according to claim 11, wherein the first group and the second group each include two lenses, a negative lens and a positive lens. 14. The first group is composed of two lenses, a negative lens and a positive lens, and the third group has a positive lens having a strong convex surface on the object side at the most object side. The zoom lens according to claim 11, wherein: