KR100467954B1 - Compact zoom lens - Google Patents

Abstract

The present invention discloses a compact zoom lens.

A compact zoom lens according to the present invention includes a lens having at least one negative refractive power and a lens having positive refractive power in order from an object side, the first lens group having negative refractive power; A second lens group including a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power, and having a positive refractive power; And a third lens group having at least one positive refractive power, the third lens group having a positive refractive power, and wherein the first, second, and third lens groups move along the optical axis. And, , (f _W : total focal length at the wide-angle end, f _T : total focal length at the telephoto end, t _II : total thickness of the second lens group).

According to the present invention, it is possible to provide a compact zoom lens having a high magnification ratio of 2.5 to 3 times with a relatively simple configuration, and in particular, chromatic aberration is well corrected.

Description

Compact zoom lens {COMPACT ZOOM LENS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens, and more particularly, to a compact zoom lens used in a camera using an imaging element such as a CCD (charge coupled device).

In recent years, the spread of electronic still cameras and video cameras using CCDs and solid-state imaging devices has been rapidly expanding, and are becoming smaller, lighter, and lower cost. Accordingly, there is a strong demand for a compact, lightweight, and low-cost lens for a zoom lens built into a camera.

In the optical system using the solid-state image sensor, since the crystal filter is used to prevent moiré phenomenon caused by the periodic structure of the image sensor, the thickness and position of the crystal filter should be taken into consideration when designing the optical system. In particular, the telecentricity of the light rays incident on the top surface is an important variable in the design.

Conventional optical systems using such a solid-state imaging device include the following.

1) Japanese Patent Publication No. 56-123512

2) Japanese Patent Application Laid-Open No. 6-94996

3) Japanese Patent Laid-Open No. 63-292106

4) Japanese Patent Laid-Open No. 5-173071

The zoom lens disclosed in 1) of the prior art is composed of a first lens group having negative refractive power and a second lens group having positive refractive power in order from the object side, and the second lens group moves to perform shifting and the first lens group. The lens group moves to compensate for the shift in the store. However, since the first lens group and the second lens group are shifted on the optical axis to perform the shifting, the overall length is greatly changed during zooming, and thus the barrel configuration is complicated and the zoom ratio, that is, the shift ratio is more than doubled. It is difficult to implement, and in particular, it is difficult to miniaturize.

In the zoom lens disclosed in 2), a third lens group having negative or positive refractive power is disposed on the upper side of the second lens group to increase the ratio of magnification in the two-group zoom method and to make the entire lens compact. 3 group zoom lens In this zoom lens, the first lens group and the second lens group move on the optical axis to perform the shift, and the third lens group is fixed, but the overall length is changed and the ratio is only about 2 times.

And the zoom lens disclosed in 3) is an optical system having a structure in which the electric field does not change when zooming, and includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a positive refractive power fixed at the time of zooming. The branch consists of a third lens group, and the second lens group and the third lens group move on the optical axis when zooming. Since the zoom lens has a structure in which the second lens group and the third lens group move toward the object side during zooming, the overall length of the entire optical system is increased for the performance correction at the wide-angle end. Therefore, miniaturization is difficult.

The zoom lens disclosed in 4) sequentially includes a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power sequentially from the object side. It is made of, because the structure of each lens group to move at the time of zooming has a disadvantage in the complicated configuration of the barrel.

Therefore, the technical problem to be achieved by the present invention is to provide a zoom lens that has a relatively simple structure made of a small number of lenses while having a high aspect ratio as a photographing optical system of a camera using an imaging device, and can be easily miniaturized.

It is also an object to provide a compact zoom lens having high optical performance in which chromatic aberration is well corrected.

1 is a diagram illustrating a zoom position structure of a compact zoom lens according to a first exemplary embodiment of the present invention.

2A and 2B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the first embodiment of the present invention, respectively.

3 is a diagram illustrating a zoom position structure of a compact zoom lens according to a second exemplary embodiment of the present invention.

4A and 4B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the second embodiment of the present invention, respectively.

5 is a diagram illustrating a zoom position structure of a compact zoom lens according to a third exemplary embodiment of the present invention.

6A and 6B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the third embodiment of the present invention, respectively.

7 is a diagram illustrating a zoom position structure of a compact zoom lens according to a fourth exemplary embodiment of the present invention.

8A and 8B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the fourth embodiment of the present invention, respectively.

9 is a diagram illustrating a zoom position structure of a compact zoom lens according to a fifth exemplary embodiment of the present invention.

10A and 10B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the fifth embodiment of the present invention, respectively.

11 is a diagram illustrating a structure of each zoom position of a compact zoom lens according to a sixth exemplary embodiment of the present invention.

12A and 12B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the sixth embodiment of the present invention, respectively.

FIG. 13 is a diagram illustrating a zoom position structure of a compact zoom lens according to a seventh exemplary embodiment of the present invention. FIG.

14A and 14B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the seventh embodiment of the present invention, respectively.

FIG. 15 is a diagram illustrating a zoom position structure of a compact zoom lens according to an eighth exemplary embodiment of the present invention. FIG.

16A and 16B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the eighth embodiment of the present invention, respectively.

FIG. 17 is a diagram illustrating a zoom position structure of a compact zoom lens according to a ninth embodiment.

18A and 18B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the ninth embodiment of the present invention, respectively.

19 is a diagram illustrating a structure of each zoom position of a compact zoom lens according to a tenth exemplary embodiment of the present invention.

20A and 20B are aberration diagrams at the wide-angle end and the telephoto end of the compact zoom lens according to the tenth embodiment of the present invention, respectively.

In order to achieve the technical problem of the present invention, the compact zoom lens according to the first aspect of the present invention includes a lens having at least one negative refractive power and a lens having positive refractive power in order from the object side. A first lens group having refractive power; A second lens group including a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power, and having a positive refractive power; And a lens having at least one positive refractive power, the third lens group having a positive refractive power, wherein the first, second, and third lens groups move along the optical axis. And, , (f _W : total focal length at the wide-angle end, f _T : total focal length at the telephoto end, t _II : total thickness of the second lens group).

Also, , (f _III : focal length of the third lens group, L _II : amount of movement from the wide-angle end to the telephoto end of the second lens group) can be further satisfied.

Besides, f _{i (−)} : the focal length of the lens having the negative refractive power of the first lens group, f _{I (+)} : the focal length of the lens having the positive refractive power of the first lens group can be satisfied.

In addition, the zoom lens according to the second aspect of the present invention includes: a first lens group having negative refractive power in order from the object side; A first lens having a positive refractive power, a second lens having a positive refractive power, and a third lens having a negative refractive power, wherein two lenses of the first to third lenses are joined to form at least one joint lens; A second lens group having a positive refractive power as a whole; And a third lens group having positive refractive power, wherein the first, second, and third lens groups move along the optical axis when the wide angle end is shifted from the telephoto end, , And The condition of (D _IIW : distance on the optical axis between the second lens group and the third lens group at the wide-angle end) is satisfied.

In addition, the zoom lens according to the third aspect of the present invention includes: a first lens group having negative refractive power in order from the object side; A second lens group including a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power, and having a positive refractive power as a whole; And a third lens group having a positive refractive power, wherein the first, second, and third lens groups move along the optical axis when the wide angle end is shifted from the telephoto end. And,, , , And Conditions (L _III : the amount of movement from the wide-angle end to the telephoto end of the third lens group) are satisfied.

Zoom lens according to a feature of the present invention (N _II1 : refractive index of the first positive lens of the second lens group from the object side, n _II2 : refractive index of the second positive lens of the second lens group from the object side) may be further satisfied.

In the zoom lens according to the present invention having these characteristics, the third lens group may be composed of one lens. In addition, the first lens group and the second lens group may include at least one aspherical surface. In addition, in the second lens group, two lenses of the first to third lenses may be joined to form at least one bonded lens.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, an embodiment of the present invention for providing a zoom lens having a simple structure while having a high aspect ratio as a photographing optical system of a camera using an imaging device will be described.

1, 3, 5, 7, 7, 9, 11, 13, 15, 17, and 19, the structure of the compact zoom lens according to each embodiment of the present invention is shown for each zoom position. have.

1, 3, 5, 7, 7, 9, 11, 13, 15, 17, and 19, a compact zoom lens according to an embodiment of the present invention is an object. First lens group I having negative refractive power (N) positioned in order from the side, Second lens group II having positive refractive power (P), and Third lens having positive refractive power It consists of group III, and the aperture A is located between 1st lens group I and 2nd lens group II.

The first lens group I includes a lens having negative refractive power and a lens having positive refractive power, and may also include at least one aspherical lens.

The second lens group II includes a lens having positive refractive power, a lens having positive refractive power, and a lens having negative refractive power, which are arranged in order from the object side, wherein a lens having positive refractive power and a lens having negative refractive power are bonded to each other. Can be. Therefore, the second lens group II may include at least one bonding lens. It may also include at least one aspherical lens.

The third lens group III includes a lens having at least one positive refractive power.

In the small zoom lens according to the embodiment of the present invention having such an NPP structure, it is shown in FIGS. 1, 3, 5, 7, 7, 9, 11, 13, 15, 17, and 19. As can be seen, each lens group moves from the wide-angle end to the telephoto end when shifting. At this time, the interval between the first lens group I and the second lens group II decreases, and the interval between the second lens group II and the third lens group III varies in the increasing direction. Is done.

The detailed structure of each lens group will be described in more detail in the first to tenth embodiments described below.

Next, the operation of the compact zoom lens according to the embodiment of the present invention having such a structure will be described.

The zoom lens according to the embodiment of the present invention performs a shift by shifting the second lens group II on the optical axis so that the zoom lens has a relatively simple configuration and has a high ratio of magnification. The lens group I and the third lens group III move and compensate.

Specifically, the first lens group I or the first lens group I and the third lens group III are moved non-linearly to compensate for the image shift occurring when the shift is performed, and the first lens group I or The third lens group III is moved to perform focus position correction, that is, focusing according to variation. Therefore, when focusing with the first lens group I, there is an advantage that the focusing group does not change due to zooming. When focusing with the third lens group III, the movable group, that is, the moving lens group, is small. This makes it easy to downsize the whole optical system.

Meanwhile, in the embodiment, the first lens group I having negative refractive power and the second lens group II having positive refractive power are positioned on the object side to secure a sufficient amount of ambient light while having a wide angle of view of 60 ° or more at the wide angle end. In particular, by disposing a lens having a high dispersion value in the first lens group (I) to reduce the magnification chromatic aberration necessary for high resolution. In addition, a convex lens having positive refractive power is disposed in the third lens group III so as to secure a sufficiently long postfocal distance so that telecentricity, which is a problem when an imaging medium such as an imaging device is used, is used. In order for the chief ray of the incident light beam to be incident at right angles to the image pickup device, the exit pupil position can be made as far as possible from the imaging medium.

In addition, the refractive power is arranged from the object side to the first lens group I in a negative and positive order, and a lens having a high refractive power is used for a lens having a refractive power of. The magnification chromatic aberration is sufficient even in an optical system having a high magnification of 3 times or more. To be corrected. In addition, an aspherical surface is suitably used for the first lens group I to minimize distortion aberration and to have sufficient imaging performance to be suitable as an imaging optical system for an imaging device of a high pixel.

Further, by dispersing the refractive power in the order of positive, positive, and negative in the second lens group II, good optical performance was obtained for the entire screen, and sufficient imaging performance was obtained to be suitable for the imaging device.

As in the present invention, since the refractive power of the second lens group II is strong in the optical system having a negative, positive, and positive structure, the air gap of each lens greatly affects the optical performance. Therefore, in the embodiment of the present invention, the positive lens having the strong refractive power and the negative lens are bonded to the second lens group II to minimize the performance change due to the air gap and the eccentricity of the lens.

The compact zoom lens according to the embodiment of the present invention having this feature satisfies the following conditions.

(Condition 1)

Here, f _W represents the total focal length at the wide-angle end, f _T represents the total focal length at the telephoto end, and L _II represents the amount of movement from the wide-angle end to the telephoto end of the second lens group II.

Condition 1 above defines the ratio of the movement amount of the second lens group (II) to the combined focal length at the wide-angle end and the telephoto end, and it is easy to miniaturize by appropriately defining the movement amount of the second lens group (II) when shifting. It is intended to be terminated.

When the upper limit of Conditional Expression 1 is exceeded, the refractive power of the second lens group II is weakened and the amount of movement of the second lens group II from the wide-angle end to the telephoto end becomes large, resulting in an increase in the lens length. It becomes difficult.

On the other hand, when the lower limit value of Condition 1 is exceeded, the refractive power of the second lens group (II) becomes stronger, so that the necessary post focal length is not sufficiently secured at the wide-angle end. It becomes difficult to correct.

The compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 2)

Here, f _III represents the focal length of the third lens group III.

Condition 2 defines the ratio of the focal length of the third lens group (III) to the composite focal length at the wide-angle end and the telephoto end, and is to secure telecentricity for an optical system suitable for an imaging medium such as an imaging device. .

When the upper limit of Conditional Expression 2 is exceeded, the refractive power of the third lens group III is weakened, making it difficult for the optical system to have telecentricity. That is, when the refractive power of the third lens group III is weakened, the exit pupil position becomes closer to the image surface, making it difficult to secure telecentricity.

On the other hand, when the lower limit value of Conditional Expression 2 is exceeded, the refractive power of the third lens group III becomes strong, making it difficult to control the astigmatism, and as a result, good aberration correction is not achieved.

In addition, the compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 3)

Here, t _II represents the total thickness of the second lens group II.

Condition 3 defines the ratio of the total thickness of the second lens group (II) to the combined focal length at the wide-angle end and the telephoto end.

When the upper limit of Conditional Expression 3 is exceeded, the total length of the optical system, in particular, when the barrel is accommodated inside the camera, becomes large, which makes it difficult to downsize the system (camera).

On the other hand, when the lower limit value of Conditional Expression 3 is exceeded, the refractive power of the second lens group II becomes strong, and it becomes difficult to sufficiently secure the postfocal distance required at the wide-angle end.

In addition, the compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 4)

Here, f _{I (−)} represents a focal length of a lens (negative lens) having negative refractive power in the first lens group _I , and f _{I (+)} represents a lens having positive refractive power in the first lens group I. The focal length of the (definition lens) is shown.

Conditional Expression 4 defines the focal length ratio between the negative lens and the positive lens in the first lens group I.

When the upper limit value of Conditional Expression 4 is exceeded, the refractive power of the positive lens becomes stronger, which makes it difficult to correct distortion and astigmatism. On the other hand, when the lower limit value of Conditional Expression 4 is exceeded, the refractive power of the negative lens becomes stronger, which makes it difficult to correct magnification chromatic aberration.

In addition, the compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 5)

Conditional Expression 5 relates to a variable ratio, and to implement a high variable ratio of about 2.8 to 3 times. If the conditional expression 5 is not satisfied, the variable magnification ratio to be implemented by the zoom lens according to the exemplary embodiment of the present invention cannot be obtained.

The compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 6)

Here, L _III represents the amount of movement from the wide-angle end to the telephoto end of the third lens group III.

Conditional Expression 6 defines the ratio of the movement amount of the third lens group III to the combined focal length at the wide-angle end and the telephoto end, and relates to the movement amount of the third lens group III when focusing according to the subject position.

When focusing is performed by the movement of the third lens group III, the amount of movement of the focusing lens group, that is, the third lens group III, is increased at the telephoto end rather than at the wide-angle end. Therefore, when the upper limit value of the above Conditional Expression 6 is exceeded, the position of the third lens group III in the telephoto end is far from the upper surface, making it difficult to miniaturize the mechanical structure when the lens is stored in the camera. . On the other hand, when the lower limit value of Conditional Expression 6 is exceeded, the position of the third lens group III at the wide-angle end becomes far from the upper surface, making it difficult to miniaturize the mechanical structure when the lens is accommodated in the camera.

The compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 7)

Here, D _IIW represents an interval on the optical axis between the second lens group II and the third lens group III at the wide-angle end.

Condition 7 defines the ratio of the intervals on the optical axis of the second lens group II and the third lens group III to the total focal length at the wide-angle end.

When the upper limit value of Conditional Expression 7 is exceeded, the second lens group II moves at a position farther from the image surface, making it difficult to miniaturize the optical system. On the other hand, when the lower limit value of Conditional Expression 7 is exceeded, the exit pupil position becomes close to the upper surface, making it difficult to secure telecentricity.

In addition, the compact zoom lens according to the embodiment of the present invention further satisfies the following conditions.

(Condition 8)

Here, n _II1 denotes the lens closest to the object side among the lenses having positive refractive power of the second lens group II (hereinafter, referred to as “first positive lens”), and may be, for example, the third lens 3. N _II2 denotes the second lens closest to the object side (hereinafter referred to as “second positive lens”) among the lenses having positive refractive power of the second lens group II. Refractive index of the fourth lens 4).

If the conditional expression 8 is not satisfied, it is impossible to secure aberration characteristics for having a good imaging ability, for example, correction of magnification chromatic aberration becomes difficult.

Next, the first to tenth embodiments of the present invention implemented to satisfy these conditions (Conditions 1 to 8) will be described.

Where f is the focal length, ri (i = 1-14) is the radius of curvature of the lens surface, di (i = 1-14) is the thickness of the lens or the distance between the lenses, nd is the refractive index, and v is the dispersion Value. The unit of the value representing length is mm.

The F number Fno of the zoom lens according to the first embodiment of the present invention has a value of 2.84 to 5.01 between the wide-angle end and the telephoto end, and the focal length f has a value of 5.91 mm to 17.10 mm. 2ω) has a value of 60.67 ° to 21.69 °. In particular, the F number Fno at the middle stage is 3.88, the focal length f is 11.53 mm, and the angle of view 2ω is 31.93 °.

1 shows a structure of a compact zoom lens according to a first embodiment of the present invention having such characteristics. As shown in FIG. 1, the first lens group I includes a first lens 1 having negative refractive power and a concave image side, and a second lens 2 having a positive refractive power and a meniscus lens having an image side concave. The second lens group II includes a third lens 3 having positive refractive power and convex on both sides, a fourth lens 4 having positive refractive power and convex on both sides, and a fourth lens 4. And a fifth lens 5 having refractive power and concave on both sides. In addition, the third lens group III includes a sixth lens 6 having positive refractive power and having an image-side surface convex. In addition, the optical filter 7 is disposed above the sixth lens 6.

Table 1 shows exemplary values of each lens constituting the zoom lens according to the first embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 97.86200 1.500000 1.80600 40.70 * 2 4.80500 1.460000 3 8.01300 2.150000 1.84700 23.80 4 21.56000 D1 5 ∞ 0.650000 * 6 8.40900 2.720000 1.51500 63.10 * 7 -10.78100 0.180000 8 13.18300 1.880000 1.80400 46.50 9 -5.42700 0.600000 1.64800 33.80 10 4.70500 D2 11 83.14300 1.660000 1.51500 63.10 * 12 -14.85200 D3 13 ∞ 2.350000 1.51700 64.20 14 ∞ 1.700000

* Denotes aspherical surface, and the formula for aspherical surface coefficient is as follows.

x: distance from lens vertex to optical axis direction

y: distance in the direction perpendicular to the optical axis

c: Inverse of the radius of curvature at the vertex of the lens (1 / R)

K: Conic constant

A, B, C, D: Aspheric coefficient

The coefficients of each aspherical surface according to the first embodiment of the present invention calculated according to Equation 1 are shown in Table 2 below, and in the first embodiment, the image of the first lens 1 of the first lens group I is shown. Side surfaces, both surfaces of the third lens 3 of the second lens group II, and the image side surface of the sixth lens 6 of the third lens group III are aspherical surfaces.

Aspheric coefficient of the second side Aspheric coefficient of the sixth face K -0.623771 K -3.874690 A -0.331139E-04 A -0.281393E-03 B 0.479755E-05 B -0.364877E-04 C -0.219070E-06 C -0.117607E-05 D 0.109278E-08 D 0.306879E-07

Aspheric coefficient of page 7 Aspheric coefficient of the twelfth aspect K 0.030886 K -23.847538 A 0.157658E-05 A -0.638389E-03 B -0.110920E-04 B 0.249517E-04 C -0.179964E-05 C -0.334747E-06 D 0.120179E-06 D -0.101431E-07

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 3 below.

Face number Wide angle Middle Telephoto D1 14.504 5.277 2.450 D2 5.275 11.341 18.365 D3 2.589 3.081 2.611

Fig. 2A shows the aberration characteristics at the wide-angle end of the zoom lens according to the first embodiment of the present invention, which consists of these embodiment values, and Fig. 2B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the second embodiment of the present invention has a value of 2.79 to 4.81 between the wide-angle end and the telephoto end, and the focal length f has a value of 5.90 mm to 17.06 mm. The angle of view (2ω) has a value of 60.69 ° to 21.71 °. In particular, the F number Fno at the middle stage is 3.78, the focal length f is 11.76 mm, and the angle of view 2ω is 31.33 °.

3 shows a structure of a compact zoom lens according to a second embodiment of the present invention having such characteristics. As shown in Fig. 3, the structure of the compact zoom lens according to the second embodiment of the present invention is the same as that of the first embodiment.

Table 4 shows the example values of each lens constituting the zoom lens according to the second embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 86.83600 1.300000 1.75100 45.40 * 2 5.19200 1.900000 3 8.96900 1.900000 1.84700 23.80 4 19.52700 D1 5 ∞ 0.650000 * 6 8.90800 2.720000 1.51500 63.10 7 -13.18500 0.130000 8 12.13900 1.970000 1.80400 46.50 9 -5.37400 0.600000 1.64800 33.80 10 4.84100 D2 * 11 46.66500 1.630000 1.51500 63.10 12 -18.40500 D3 13 ∞ 2.350000 1.51700 64.20 14 ∞ 1.700000

* Denotes an aspherical surface, and in the second embodiment, the image side surface of the first lens 1 of the first lens group I, the object side surface of the third lens 3 of the second lens group II, and 3 Lens group III The object side surface of the 6th lens 6 is an aspherical surface. Aspheric coefficients are shown in Table 5 below.

Aspheric coefficient of the second side Aspheric coefficient of page 6 Aspheric coefficient of the eleventh aspect K -0.624595 K -3.918027 K -683.259720 A -0.427005E-04 A -0.227150E-03 A 0.511578E-03 B 0.498214E-05 B -0.205677E-04 B -0.551033E-04 C -0.127066E-06 C -0.676607E-07 C 0.285737E-05 D -0.365007E-09 D -0.348492E-07 D -0.607086E-07

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 6.

Face number Wide angle Middle Telephoto D1 16.375 5.429 2.471 D2 5.535 11.342 17.988 D3 2.584 3.269 2.632

Fig. 4A shows the aberration characteristics at the wide-angle end of the zoom lens according to the second embodiment of the present invention made up of these embodiment values, and Fig. 4B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the third embodiment of the present invention has a value of 2.84 to 4.97 between the wide-angle end and the telephoto end, and the focal length f has a value of 5.91 mm to 17.11 mm, The angle of view 2ω has a value of 60.53 ° to 21.81 °. In particular, the F number Fno at the middle stage is 3.90, the focal length f is 11.51 mm, and the angle of view 2ω is 32.15 °.

5 shows a structure of a compact zoom lens according to a third embodiment of the present invention having such characteristics. As shown in Fig. 5, the structure of the compact zoom lens according to the third embodiment of the present invention is the same as that of the first embodiment.

Table 7 shows exemplary values of each lens constituting the zoom lens according to the third embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 250.00000 1.300000 1.75100 45.40 * 2 5.06300 1.660000 3 8.74000 2.090000 1.78500 25.70 4 27.75500 D1 5 ∞ 0.640000 * 6 8.28300 2.700000 1.51500 63.10 7 -14.69900 0.100000 8 11.28000 1.950000 1.80400 46.50 9 -5.37700 0.600000 1.64800 33.80 10 4.45700 D2 11 37.50000 1.740000 1.51500 63.10 * 12 -16.76800 D3 13 ∞ 2.350000 1.51700 64.20 14 ∞ 1.700002

* Denotes an aspherical surface, and in the third embodiment, an image side surface of the first lens 1 of the first lens group I, an object side surface of the third lens 3 of the second lens group II, and The image side surface of the sixth lens 6 of the three lens group III is an aspherical surface. The coefficients of each aspherical surface are shown in Table 8 below.

Aspheric coefficient of the second side Aspheric coefficient of page 6 Aspheric coefficient of the twelfth aspect K -0.697695 K -3.016323 K -35.579202 A 0.104106E-04 A -0.227999E-03 A -0.725275E-03 B 0.270822E-05 B -0.257731E-04 B 0.299853E-04 C -0.137393E-06 C 0.633420E-06 C -0.706392E-06 D 0.133649E-08 D -0.703879E-07 D 0.467696E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 9 below.

Face number Wide angle Middle Telephoto D1 16.300 6.010 2.452 D2 5.222 11.777 18.338 D3 2.691 2.691 2.691

Fig. 6A shows the aberration characteristics at the wide-angle end of the zoom lens according to the third embodiment of the present invention made up of these embodiment values, and Fig. 6B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the fourth embodiment of the present invention has a value of 2.80 to 4.84 between the wide-angle end and the telephoto end, and the focal length f has a value of 5.91 mm to 17.06 mm. The angle of view (2ω) has a value of 60.59 ° to 21.88 °. In particular, the F number Fno at the intermediate stage is 3.85, the focal length f is 11.75 mm, and the angle of view 2ω is 31.49 °.

7 shows a structure of a compact zoom lens according to a fourth embodiment of the present invention having such characteristics. As shown in FIG. 7, the structure of the compact zoom lens according to the fourth embodiment of the present invention is the same as that of the first embodiment.

Table 10 shows an example value of each lens constituting the zoom lens according to the fourth embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 81.97600 1.300000 1.80600 40.70 * 2 5.26000 1.530000 3 8.49300 2.080000 1.84700 23.80 4 22.75600 D1 5 ∞ 0.650000 * 6 8.23200 2.630000 1.51500 63.10 * 7 -12.40800 0.140000 8 12.68000 1.910000 1.80400 46.50 9 -5.54300 0.600000 1.64800 33.80 10 4.56000 D2 11 50.10000 1.770000 1.51500 63.10 * 12 -14.25300 D3 13 ∞ 2.350000 1.51700 64.20 14 ∞ 1.700001

* Denotes an aspherical surface, and as in the first embodiment, in the fourth embodiment, an image side surface of the first lens 1 of the first lens group I and the third lens of the second lens group II ( The object side surface and the image side surface of 3) and the image side surface of the sixth lens 6 of the third lens group III are aspherical surfaces. The coefficients of each aspherical surface are shown in Table 11 below.

Aspheric coefficient of the second side Aspheric coefficient of the sixth face K -0.559111 K -3.569515 A -0.166786E-04 A -0.240665E-03 B -0.351578E-06 B -0.360723E-04 C -0.318581E-07 C -0.131973E-05 D -0.783358E-09 D 0.328949E-07

Aspheric coefficient of page 7 Aspheric coefficient of the twelfth aspect K 0.617655 K -23.070513 A -0.391816E-04 A -0.767529E-03 B -0.118013E-04 B 0.283532E-04 C -0.179714E-05 C -0.500196E-06 D 0.110012E-06 D -0.280553E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 12 below.

Face number Wide angle Middle Telephoto D1 16.610 5.800 2.500 D2 4.974 11.509 17.6734 D3 2.675 2.784 2.675

Fig. 8A shows the aberration characteristics at the wide-angle end of the zoom lens according to the fourth embodiment of the present invention, which consists of these embodiment values, and Fig. 8B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the fifth embodiment of the present invention has a value of 2.87 to 5.01 between the wide-angle end and the telephoto end, and the focal length f has a value of 5.91 mm to 17.08 mm. The angle of view (2ω) has a value of 60.57 ° to 21.88 °. In particular, the F 7 number Fno at the middle stage is 3.94, the focal length f is 11.50 mm, and the angle of view 2ω is 32.19 °.

9 shows a structure of a compact zoom lens according to a fifth embodiment of the present invention having such characteristics. As shown in Fig. 9, the structure of the compact zoom lens according to the fifth embodiment of the present invention is the same as that of the first embodiment.

Table 13 shows exemplary values of each lens constituting the zoom lens according to the fifth embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 198.34000 1.300000 1.80600 40.70 * 2 5.23300 1.650000 3 9.18900 2.030000 1.84700 23.80 4 30.91100 D1 5 ∞ 0.650000 * 6 8.25300 2.720000 1.51500 63.10 7 -14.20600 0.100000 8 11.54100 1.970000 1.80400 46.50 9 -5.29200 0.600000 1.64800 33.80 10 4.43900 D2 11 38.79700 1.730000 1.51500 63.10 * 12 -16.61800 D3 13 ∞ 2.350000 1.51700 64.20 14 ∞ 1.700881

* Denotes an aspherical surface, and in the fifth embodiment, the image side surface of the first lens 1 of the first lens group I and the third lens of the second lens group II The object side surface of 3) and the image side surface of the sixth lens 6 of the third lens group III are aspherical surfaces. The coefficients of each aspherical surface are shown in Table 14 below.

Aspheric coefficient of the second side Aspheric coefficient of page 6 Aspheric coefficient of the twelfth aspect K -0.649217 K -3.118592 K -30.793494 A -0.399494E-04 A -0.221615E-03 A -0.643456E-03 B 0.372675E-06 B -0.303817E-04 B 0.228798E-04 C -0.639370E-07 C 0.136226E-05 C -0.368614E-06 D -0.165169E-09 D -0.123324E-06 D -0.260155E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 15 below.

Face number Wide angle Middle Telephoto D1 16.306 6.004 2.450 D2 5.217 11.756 18.275 D3 2.683 2.683 2.683

Fig. 10A shows the aberration characteristics at the wide-angle end of the zoom lens according to the fifth embodiment of the present invention made up of these embodiment values, and Fig. 10B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the sixth embodiment of the present invention has a value of 2.82 to 5.03 between the wide-angle end and the telephoto end, and the focal length f has a value of 8.17 mm to 23.59 mm, The angle of view (2ω) has a value of 59.27 ° to 21.48 °. In particular, the F number Fno at the intermediate stage is 3.87, the focal length f is 15.73 mm, and the angle of view 2ω is 31.97 °.

11 shows a structure of a compact zoom lens according to a sixth embodiment of the present invention having such characteristics. As shown in FIG. 11, the structure of the zoom lens according to the sixth embodiment of the present invention is the same as that of the first embodiment.

Table 16 shows the example values of each lens constituting the zoom lens according to the sixth embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 200.00000 1.500000 1.75110 45.40 * 2 6.68500 2.530000 3 12.19000 2.330000 1.80520 25.50 4 36.19000 D1 5 ∞ 0.620000 * 6 10.09200 3.400000 1.51450 63.10 * 7 -13.01700 0.320000 8 16.59200 2.210000 1.83500 43.00 9 -7.81100 0.600000 1.67270 32.20 10 5.55500 D2 11 21.14300 2.540000 1.51450 63.10 * 12 -57.88500 D3 13 ∞ 3.000000 1.51680 64.20 14 ∞ 1.399995

* Denotes an aspherical surface, and as in the first embodiment, an image side surface of the first lens 1 of the first lens group I and an object side surface of the third lens 3 of the second lens group II And the image side surface and the image side surface of the sixth lens 6 of the third lens group III are aspherical surfaces. The coefficients of each aspherical surface are shown in Table 17 below.

Aspheric coefficient of the second side Aspheric coefficient of the sixth face K -0.608787 K -4.399275 A -0.387634E-04 A -0.148111E-03 B 0.417507E-06 B -0.166945E-04 C -0.234979E-07 C -0.630067E-06 D 0.886247E-10 D 0.356648E-09

Aspheric coefficient of page 7 Aspheric coefficient of the twelfth aspect K 1.661785 K 29.763660 A -0.780982E-04 A 0.561824E-04 B -0.739383E-05 B -0.443075E-05 C -0.574547E-06 C 0.163025E-06 D 0.107518E-07 D -0.225716E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 18 below.

Face number Wide angle Middle Telephoto D1 19.458 6.717 2.450 D2 8.465 16.752 25.854 D3 2.915 2.870 2.004

Fig. 12A shows the aberration characteristics at the wide-angle end of the zoom lens according to the sixth embodiment of the present invention made up of these embodiment values, and Fig. 12B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the seventh embodiment of the present invention has a value between 2.81 and 4.98 between the wide-angle end and the telephoto end, and the focal length f has a value between 8.21 mm and 23.63 mm. The angle of view 2ω has a value of 59.02 ° to 21.42 °. In particular, the F number Fno in the middle stage is 3.88, the focal length f is 15.76 mm, and the angle of view 2ω is 31.84 °.

FIG. 13 shows a structure of a compact zoom lens according to a seventh embodiment of the present invention having such characteristics. As shown in FIG. 13, the structure of the compact zoom lens according to the seventh embodiment of the present invention is the same as that of the first embodiment.

Table 19 shows an example value of each lens constituting the zoom lens according to the seventh embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 199.20000 1.500000 1.80430 40.90 * 2 7.01500 2.370000 3 12.76000 2.350000 1.84700 23.80 4 45.13200 D1 5 ∞ 0.600000 * 6 10.45500 3.400000 1.51450 63.10 7 -19.21000 0.440000 8 13.50000 2.400000 1.83500 43.00 9 -7.18000 0.600000 1.67270 32.20 10 5.53000 D2 11 20.04000 2.550000 1.51450 63.10 * 12 -54.50000 D3 13 ∞ 3.000000 1.51680 64.20 14 ∞ 1.400000

* Denotes an aspherical surface, in the seventh embodiment, the image side surface of the first lens 1 of the first lens group I, the object side surface of the third lens 3 of the second lens group II, and The image side surface of the sixth lens 6 of the third lens group III is an aspherical surface. The coefficients of each aspherical surface are shown in Table 20 below.

Aspheric coefficient of the second side Aspheric coefficient of the sixth face Aspheric coefficient of page 12 K -0.600402 K -3.536689 K 84.603002 A -0.419472E-04 A -0.334452E-04 A 0.973303E-04 B 0.269824E-06 B -0.555785E-05 B -0.170802E-05 C -0.216852E-07 C -0.143368E-06 C 0.514340E-07 D 0.136418E-09 D 0.231754E-08 D 0.132618E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 21 below.

Face number Wide angle Middle Telephoto D1 20.081 7.262 2.460 D2 8.267 17.103 25.583 D3 2.941 2.310 2.003

Fig. 14A shows the aberration characteristics at the wide-angle end of the zoom lens according to the seventh embodiment of the present invention which consists of these embodiment values, and Fig. 14B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the eighth embodiment of the present invention has a value of 2.82 to 5.02 between the wide-angle end and the telephoto end, and the focal length f has a value of 8.21 mm to 23.63 mm. The angle of view 2ω has a value of 59.00 ° to 21.41 °. In particular, the F number Fno at the middle stage is 3.91, the focal length f is 15.78 mm, and the angle of view 2ω is 31.77 °.

15 shows a structure of a compact zoom lens according to an eighth embodiment of the present invention having this characteristic. As shown in FIG. 15, the structure of the compact zoom lens according to the eighth embodiment of the present invention is the same as that of the first embodiment.

Table 22 shows the example values of each lens constituting the zoom lens according to the eighth embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 250.00000 1.500000 1.80430 40.90 * 2 6.94800 2.330000 3 12.64700 2.490000 1.84700 23.80 4 46.07000 D1 5 ∞ 0.600000 * 6 10.21000 3.500000 1.51450 63.10 7 -18.91800 0.290000 8 13.73000 2.370000 1.83500 43.00 9 -7.10200 0.600000 1.67270 32.20 10 5.52100 D2 11 22.16300 2.550000 1.51680 64.20 12 -40.60000 D3 13 ∞ 3.000000 1.51680 64.20 14 ∞ 1.400000

* Denotes an aspherical surface, and in the eighth embodiment, only the image side surface of the first lens 1 of the first lens group I and the object side surface of the third lens 3 of the second lens group II are shown. Aspheric The coefficient of each aspherical surface is shown in Table 23.

Aspheric coefficient of the second side Aspheric coefficient of the sixth face K -0.708475 K -3.585380 A -0.304314E-05 A -0.252737E-04 B 0.465971E-06 B -0.545103E-05 C -0.229706E-07 C -0.215667E-06 D 0.209566E-09 D 0.432513E-08

And the distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens ( The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 24 below.

Face number Wide angle Middle Telephoto D1 19.930 7.276 2.497 D2 8.754 17.626 26.029 D3 2.719 2.045 1.811

Fig. 16A shows the aberration characteristics at the wide-angle end of the zoom lens according to the eighth embodiment of the present invention, which consists of these embodiment values, and Fig. 16B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the ninth embodiment of the present invention has a value of 2.80 to 5.01 between the wide-angle end and the telephoto end, and the focal length f has a value of 7.95 mm to 22.72 mm. The angle of view (2ω) has a value of 60.60 ° to 22.24 °. In particular, the F number Fno at the middle stage is 3.93, the focal length f is 15.15 mm, and the angle of view 2ω is 33.00 °.

17 shows a structure of a compact zoom lens according to a ninth embodiment of the present invention having such characteristics. As shown in FIG. 17, the structure of the compact zoom lens according to the ninth embodiment of the present invention is the same as that of the first embodiment.

Table 25 shows an example value of each lens constituting the zoom lens according to the ninth embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 250.00000 1.500000 1.80430 40.90 * 2 6.76200 2.330000 3 12.52400 2.330000 1.84700 23.80 4 46.97400 D1 5 ∞ 0.600000 * 6 10.12000 3.500000 1.51450 63.10 7 -18.16200 0.360000 8 13.99200 2.340000 1.83500 43.00 9 -7.02000 0.600000 1.67270 32.20 10 5.50000 D2 11 20.56900 2.160000 1.51680 64.20 12 -40.27200 D3 13 ∞ 3.000000 1.51680 64.20 14 ∞ 1.400000

* Denotes an aspherical surface, and as in the eighth embodiment, an image side surface of the first lens 1 of the first lens group I and an object side surface of the third lens 3 of the second lens group II. Only aspherical surface. The coefficient of each aspherical surface is shown in Table 26 below.

Aspheric coefficient of the second side Aspheric coefficient of the sixth face K -0.795625 K -3.602351 A 0.245386E-04 A -0.313322E-04 B 0.608104E-06 B -0.486705E-05 C -0.237189E-07 C -0.304382E-06 D 0.229752E-09 D 0.753285E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 27 below.

Face number Wide angle Middle Telephoto D1 19.618 7.869 2.948 D2 8.415 17.781 25.946 D3 3.020 1.827 1.804

Fig. 18A shows the aberration characteristics at the wide-angle end of the zoom lens according to the ninth embodiment of the present invention made up of these embodiment values, and Fig. 18B shows the aberration characteristics at the telephoto end.

In addition, the F number Fno of the zoom lens according to the tenth embodiment of the present invention has a value between 2.83 and 5.11 between the wide-angle end and the telephoto end, and the focal length f has a value between 7.81 mm and 22.33 mm. The angle of view 2ω has a value of 61.48 ° to 22.68 °. In particular, the F number Fno at the middle stage is 3.90, the focal length f is 14.79 mm, and the angle of view 2ω is 33.95 °.

19 shows a structure of a compact zoom lens according to a tenth embodiment of the present invention having such characteristics. As shown in Fig. 19, the structure of the compact zoom lens according to the tenth embodiment of the present invention is the same as that of the first embodiment.

Table 28 shows an example value of each lens constituting the zoom lens according to the tenth embodiment of the present invention.

Face number Radius of curvature (r) Thickness, distance (d) Refractive index (nd) Variance (v) One 117.00000 1.350000 1.80430 40.90 * 2 6.43000 2.380000 3 11.90000 2.190000 1.84700 23.80 4 38.65000 D1 5 ∞ 1.000000 * 6 9.31500 3.100000 1.51450 63.10 7 -17.27000 0.640000 8 13.76700 2.150000 1.83500 43.00 9 -6.84300 0.600000 1.67270 32.20 10 5.21200 D2 11 16.38900 2.120000 1.51450 63.10 * 12 -56.42800 D3 13 ∞ 3.000000 1.51680 64.20 14 ∞ 1.400000

* Denotes an aspherical surface, and in the tenth embodiment, the image side surface of the first lens 1 of the first lens group I, the object side surface of the third lens 3 of the second lens group II, and the In the third lens group III, the image side surface of the sixth lens 6 is an aspherical surface. Aspheric coefficients are shown in Table 29.

Aspheric coefficient of the second side Aspheric coefficient of page 6 Aspheric coefficient of the twelfth aspect K -0.693073 K -3.423521 K -371.401149 A -0.196889E-04 A -0.506532E-05 A -0.213806E-03 B 0.212599E-05 B -0.798962E-05 B 0.503883E-05 C -0.892076E-07 C -0.131727E-06 C -0.112616E-06 D 0.104081E-08 D 0.153389E-08 D 0.125043E-08

The distance D1 between the second lens 2 and the third lens 3 changed during zooming, the distance D2 between the fifth lens 5 and the sixth lens 6, and the sixth lens The change amount of the distance D3 between 6) and the optical filter 7 is shown in Table 30.

Face number Wide angle Middle Telephoto D1 17.525 6.166 2.127 D2 8.080 16.365 25.262 D3 2.558 2.257 1.405

Fig. 20A shows the aberration characteristics at the wide-angle end of the zoom lens according to the tenth embodiment of the present invention, which consists of these embodiment values, and Fig. 20B shows the aberration characteristics at the telephoto end.

The zoom lenses according to the exemplary embodiments of the present invention configured as such exemplary embodiments satisfy the above-described conditions (Conditions 1 to 8), and the exemplary values of the respective Conformations are shown in Table 31 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Conditional Expression 1 1.30 1.25 1.30 1.26 1.30 Conditional Expression 2 2.44 2.57 2.25 2.16 2.26 Conditional Expression 3 0.54 0.54 0.53 0.53 0.54 Conditional Expression 4 0.45 0.41 0.45 0.47 0.45 Conditional Expression 5 2.89 2.89 2.89 2.88 2.89 Conditional Expression 6 0.002 0.005 0.000 0.000 0.000 Conditional Expression 7 0.89 0.94 0.88 0.84 0.88 Conditional Expression 8 0.29 0.29 0.29 0.29 0.29

Example 6 Example 7 Example 8 Example 9 Example 10 Conditional Expression 1 1.19 1.18 1.18 1.21 1.21 Conditional Expression 2 2.18 2.06 2.01 1.98 1.88 Conditional Expression 3 0.47 0.49 0.49 0.51 0.49 Conditional Expression 4 0.42 0.45 0.45 0.44 0.44 Conditional Expression 5 2.89 2.88 2.88 2.86 2.86 Conditional Expression 6 -0.07 -0.07 -0.07 -0.09 -0.09 Conditional Expression 7 1.04 1.01 1.07 1.06 1.04 Conditional Expression 8 0.32 0.32 0.32 0.32 0.32

The present invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the following claims.

According to the embodiment of the present invention as described above, it is possible to provide a zoom lens having a high magnification ratio of 2.8 times to 3 times with a relatively simple configuration.

In particular, it is possible to provide a small wide-angle zoom lens of high optical performance that can be used at a wide angle and has telecentricity suitable for a solid-state imaging device such as a CCD and has good chromatic aberration.

Claims (10)

In order from the object side, A first lens group including at least one lens having negative refractive power and a lens having positive refractive power and having negative refractive power as a whole; A second lens group including a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power, and having a positive refractive power as a whole; And A third lens group including a lens having at least one positive refractive power and having positive refractive power as a whole Wherein the first, second, and third lens groups move along the optical axis and satisfy the following conditions. f _W : Total focal length at wide end f _T : total focal length from telephoto t _Ⅱ : Overall thickness of the second lens group L _II : Amount of movement from the wide-angle end to the telephoto end of the second lens group In order from the object side, A first lens group having negative refractive power; A first lens having a positive refractive power, a second lens having a positive refractive power, and a third lens having a negative refractive power, wherein two lenses of the first to third lenses are joined to form at least one joint lens; A second lens group having a positive refractive power as a whole; And Third lens group having positive refractive power And a first lens group, a second lens group, and a third lens group moving along the optical axis when the optical lens is shifted from the wide-angle end to the telephoto end. f _W : Total focal length at wide end f _T : total focal length from telephoto t _Ⅱ : Overall thickness of the second lens group D _IIW : Spacing on the optical axis between the second lens group and the third lens group at the wide-angle end. L _II : Amount of movement from the wide-angle end to the telephoto end of the second lens group In order from the object side, A first lens group having negative refractive power; A second lens group including a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power, and having a positive refractive power as a whole; And Third lens group having positive refractive power And a first lens group, a second lens group, and a third lens group moving along the optical axis when the optical lens is shifted from the wide-angle end to the telephoto end. f _W : Total focal length at wide end f _T : total focal length from telephoto t _Ⅱ : Overall thickness of the second lens group L _II : Amount of movement from the wide-angle end to the telephoto end of the second lens group L _III : Movement amount from the wide-angle end to the telephoto end of the third lens group D _IIW : Spacing on the optical axis between the second lens group and the third lens group at the wide-angle end. The zoom lens according to any one of claims 1 to 3, which further satisfies the following conditions. f _III : Focal length of the third lens group The method according to claim 2 or 3, And the first lens group comprises a lens having at least one negative refractive power and a lens having positive refractive power. The zoom lens according to any one of claims 1 to 3, which further satisfies the following conditions. f _{I (-)} : Focal length of the lens having negative refractive power in the first lens group f _{I (+)} : Focal length of the lenses having positive refractive power in the first lens group The zoom lens according to any one of claims 1 to 3, which further satisfies the following conditions. n _II1 : First positive lens of the second lens group n _II2 : Second positive lens of the second lens group The method according to any one of claims 1 to 3, A zoom lens, wherein the third lens group comprises a lens having one positive refractive power. The method according to any one of claims 1 to 3, And the first lens group and the second lens group include at least one aspherical surface. The method according to claim 1 or 3, 2. The zoom lens of the second lens group, wherein two lenses of the first to third lenses are joined to form at least one bonded lens.