CN101344636A

CN101344636A - Three-unit zoom lens system and image pickup apparatus using the same

Info

Publication number: CN101344636A
Application number: CNA2008101303241A
Authority: CN
Inventors: 片仓正弘
Original assignee: Olympus Imaging Corp
Current assignee: Olympus Corp
Priority date: 2007-07-12
Filing date: 2008-07-11
Publication date: 2009-01-14
Anticipated expiration: 2028-07-11
Also published as: JP2009020324A; CN101344636B

Abstract

The present invention relates to a three-unit zoom lens system and an image pick-up device using the same. A three-unit zoom lens system includes in order from an object side thereof a first lens unit G1 having a negative refracting power, a second lens unit G2 having a positive refracting power, a third lens unit G3 having a negative refracting power, and an aperture stop which is at an image side of the first lens unit G1, and at the object side of a lens surface nearest to the image side of the second lens unit G2, and which moves integrally with the second lens unit. At a time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit G1 and the second lens unit G2 is narrowed, and a distance between the second lens unit G2 and the third lens unit G3 changes. The second lens unit G2 moves toward the object side at the time of zooming from the wide angle end to the telephoto end. The third lens unit G3 moves to be positioned at the object side at the telephoto end, with respect to the wide angle end. The three-unit zoom lens system satisfies predetermined conditional expressions.

Description

Three-unit zoom lens system and the image pick-up device that utilizes it

Technical field

The present invention relates to small-sized three-unit zoom lens system and use the image pick-up device such as the compact digital camera of this three-unit zoom lens system.

Background technology

In image pick-up device, seek high image quality, high convergent-divergent multiplying power and thin lens frame such as digital camera and video recorder.For example, known to so far first lens unit that has negative refractive power in comprising described in the Japanese Patent Application Laid-Open communique 2004-333572, a kind of zoom-lens system that has second lens unit of positive refractive power and have the 3rd lens unit of negative refractive power.This zoom-lens system has more favourable optical property, guarantees about 4 times high convergent-divergent multiplying power simultaneously.

In the zoom-lens system in above-mentioned communique, because the axial thickness of the 3rd lens unit is thicker, so when zoom-lens system is in the retraction state, be not easy to attenuation.

And, in the zoom-lens system in above-mentioned communique, from wide-angle side to the convergent-divergent multiplying power load concentration of telescope end in second lens unit.The 3rd lens unit seldom has or does not have convergent-divergent multiplying power load.The amount of movement of second lens unit increases.Therefore, the total length of zoom lens becomes big.

And, recently, known as in a kind of image pick-up element described in the Japanese Patent Application Laid-Open 2006-351972, become and greatly also can pick up favourable image even this image pick-up element is incident on angle around the incident ray on the part in the image pickup zone of image pick-up element.

Summary of the invention

The present invention In view of the foregoing makes, and an object of the present invention is to provide a kind of zoom-lens system that helps guaranteeing zoom ratio, miniaturization, in light weight and optical property.And another object of the present invention provides a kind of electronic image pickup apparatus that comprises this zoom-lens system.

According to a first aspect of the invention, provide a kind of three-unit zoom lens system, this three-unit zoom lens system comprises in order from object side:

First lens unit with negative refractive power;

Second lens unit with positive refractive power;

The 3rd lens unit with negative refractive power; And

Aperture diaphragm (aperture stop), this aperture diaphragm be in this first lens unit as side and be in the object side of lens surface of the most close picture side of this second lens unit, and,

From wide-angle side during to the telescope end zoom, the distance between this first lens unit and this second lens unit narrows down, and the distance between this second lens unit and the 3rd lens unit changes, and

This second lens unit is moving to object side during to the telescope end zoom from wide-angle side, and

The 3rd lens unit moves, thereby with respect to wide-angle side, is positioned at the object side place at telescope end, and

This three-unit zoom lens system satisfies the following conditions expression formula:

f _t/f _w＞3.8…(1)

d _G3/f _w＜1.0…(2)

Wherein,

f _wRepresent the focal length of this three-unit zoom lens system in wide-angle side,

f _tRepresent the focal length of this three-unit zoom lens system at telescope end, and

d _G3The optical axis thickness of representing the 3rd lens unit.

According to a second aspect of the invention, provide a kind of three-unit zoom lens system, this three-unit zoom lens system comprises in order from object side:

First lens unit with negative refractive power;

Second lens unit with positive refractive power;

The 3rd lens unit with negative refractive power; And

Aperture diaphragm, this aperture diaphragm be in this first lens unit as side and be in the object side of lens surface of the most close picture side of this second lens unit, and integrally move with this second lens unit, wherein,

3.8＜f _t/f _w＜5.5…(21)

2.0＜β ₂(t)/β ₂(w)＜3.2…(22)

1.2＜β ₃(t)/β ₃(w)＜1.8…(23)

Wherein,

f _tRepresent the focal length of this three-unit zoom lens system in wide-angle side,

f _wRepresent the focal length of this three-unit zoom lens system at telescope end,

β ₂(w) be illustrated in the horizontal convergent-divergent multiplying power of this second lens unit of wide-angle side,

β ₂(t) be illustrated in the horizontal convergent-divergent multiplying power of this second lens unit of telescope end,

β ₃(w) be illustrated in the horizontal convergent-divergent multiplying power of wide-angle side the 3rd lens unit, and

β ₃(t) be illustrated in the horizontal convergent-divergent multiplying power of telescope end the 3rd lens unit.

And, can form a kind of image pick-up device according to the three-unit zoom lens system of the present invention and the image pick-up element that will convert electric signal to by combination by the optical imagery that this three-unit zoom lens system forms.

Description of drawings

Figure 1A, Figure 1B and Fig. 1 C show the lens sectional view along optical axis according to the optical arrangement when the infinity object point focuses on of first embodiment of zoom-lens system of the present invention, wherein, Figure 1A shows the state in wide-angle side, Figure 1B shows intermediateness, and Fig. 1 C shows the state at telescope end;

Fig. 2 A, Fig. 2 B and Fig. 2 C are similarly scheming with Figure 1A, Figure 1B and Fig. 1 C respectively according to second embodiment of zoom-lens system of the present invention;

Fig. 3 A, Fig. 3 B and Fig. 3 C are similarly scheming with Figure 1A, Figure 1B and Fig. 1 C respectively according to the 3rd embodiment of zoom-lens system of the present invention;

Fig. 4 A, Fig. 4 B and Fig. 4 C are similarly scheming with Figure 1A, Figure 1B and Fig. 1 C respectively according to the 4th embodiment of zoom-lens system of the present invention;

Fig. 5 A, Fig. 5 B and Fig. 5 C are similarly scheming with Figure 1A, Figure 1B and Fig. 1 C respectively according to the 5th embodiment of zoom-lens system of the present invention;

Fig. 6 A, Fig. 6 B and Fig. 6 C show the figure according to the spherical aberration when the infinity object point focuses on, astigmatism, distortion and the convergent-divergent ratio chromatism, of first embodiment, wherein, Fig. 6 A shows the state in wide-angle side, Fig. 6 B shows intermediateness, and Fig. 6 C shows the state at telescope end;

Fig. 7 A, Fig. 7 B and Fig. 7 C are similarly the scheming with Fig. 6 A, Fig. 6 B and Fig. 6 C respectively when the infinity object point focuses on according to second embodiment;

Fig. 8 A, Fig. 8 B and Fig. 8 C are similarly the scheming with Fig. 6 A, Fig. 6 B and Fig. 6 C respectively when the infinity object point focuses on according to the 3rd embodiment;

Fig. 9 A, Fig. 9 B and Fig. 9 C are similarly the scheming with Fig. 6 A, Fig. 6 B and Fig. 6 C respectively when the infinity object point focuses on according to the 4th embodiment;

Figure 10 A, Figure 10 B and Figure 10 C are similarly the scheming with Fig. 6 A, Fig. 6 B and Fig. 6 C respectively when the infinity object point focuses on according to the 5th embodiment;

Figure 11 describes the figure that revises distortion;

Figure 12 shows the isometric front view of the outward appearance of the digital camera of incorporating with good grounds zoom-lens system of the present invention into;

Figure 13 is the rear isometric view of the digital camera among Figure 12;

Figure 14 is the sectional view of the digital camera among Figure 12; And

Figure 15 is the structured flowchart of internal circuit of the primary clustering of digital camera.

Embodiment

Below, the three-unit zoom lens system of the first kind of the present invention (according to a first aspect of the invention) is described.

In the present invention, three-unit zoom lens system has such basic structure, that is, it comprises in order from object side: first lens unit with negative refractive power, have second lens unit of positive refractive power, and the 3rd lens unit with negative refractive power; And from wide-angle side during to the telescope end zoom, distance between this first lens unit and this second lens unit narrows down, and the distance between this second lens unit and the 3rd lens unit changes, and this second lens unit is moving to object side during to the telescope end zoom from wide-angle side, and the 3rd lens unit and wide-angle side are relatively, and running fix is at the object side place of telescope end.

In such a way, be negative by the refractive power that makes first lens unit, help guaranteeing image angle, make size radially less, and reduction forms the lens unit number of zoom-lens system.Minimizing on the lens unit number also helps the minimizing number of lenses.As a result, this causes lens frame attenuation and cost to reduce.

And, change distance with first lens unit by second lens unit with positive refractive power, second lens unit is filled the post of expansion bend (variator), and by increasing the convergent-divergent multiplying power moving to image-side from object side during to the telescope end zoom from wide-angle side.

And, by negative refractive power being given the 3rd lens unit, by at telescope end the 3rd lens unit being moved the effect that realizes that the convergent-divergent multiplying power increases to object side with respect to wide-angle side.

By increasing the convergent-divergent multiplying power during to the telescope end zoom, in two lens units, that is, in second lens unit and the 3rd lens unit, can share the increase of convergent-divergent multiplying power with less amount of movement by each lens unit from wide-angle side.As a result, can be so that the total length of zoom-lens system be less, and can keep good image quality.

Because the 3rd lens unit as the final lens unit has negative refractive power, thus the symmetry of the power profile of whole zoom-lens system become well, and with the negative refractive power balance of first lens unit.Therefore, the longitudinal aberration that can provide balance and tiltedly aberration and can not cause appearance outside needing distortion and the zoom-lens system of picture planar curvature.

Also comprise aperture diaphragm according to three-unit zoom lens system of the present invention, this aperture diaphragm is in the picture side of this first lens unit, and be in the object side of lens surface of the most close picture side of this second lens unit, and integrally move with this second lens unit.

By constructing a kind of structure in such a way, can suppress to be incident on the height on first lens unit, and make the lens unit size decreases radially of winning from axial ray.And, can be so that second lens unit size decreases radially, and help dimension reduction and guarantee the positive refractive power of second lens unit.And, can prevent that emergent pupil is too near image pick-up element.And, because aperture diaphragm integrally moves with second lens unit, thereby, can simply constructed driving mechanism, help simplified structure.

And, make three-unit zoom lens system according to the present invention have the structure that satisfies the following conditions expression formula.

f _t/f _w＞3.8…(1)

d _G3/f _w＜1.0…(2)

Wherein,

d _G3The optical axis thickness of representing the 3rd lens unit.

Conditional expression (1) is the expression formula of specifying zoom ratio, and preferably, guarantees zoom ratio by constructing the lower limit that a kind of arrangement value of making is not less than in the conditional expression (1).

Conditional expression (2) is the expression formula of specifying the optical axis thickness of the 3rd lens unit.Preferably, by constructing a kind of structure, the value of making is not higher than the attenuation that higher limit in the conditional expression (2) realizes the 3rd lens unit.

And, preferably, construct a kind of structure, make three-unit zoom lens system satisfy any in the following conditions expression formula.

3＜D _w/f _w＜8…(3)

0.3＜D _t/f _t＜1.8…(4)

Wherein,

D _wRepresent the total optical axis length of this three-unit zoom lens system in wide-angle side,

D _tRepresent the total optical axis length of this three-unit zoom lens system at telescope end, and

This total optical axis length be this three-unit zoom lens system pass through to be added into the length that optical axis thickness was obtained from the exit surface of the lens of the through the most close image of the incidence surface of the lens of close object with the back focus (back force) that the air characteristic chamber length is expressed.

Conditional expression (3) and (4) are the expression formulas of specifying the preferred overall length of three-unit zoom lens system.By constructing a kind of structure, the value of making is not higher than the higher limit in conditional expression (3) and (4), helps attenuation in use.And by constructing a kind of arrangement, feasible value is not less than the lower limit in conditional expression (3) and (4), the feasible refractive power that suppresses each lens unit, and the reduction longitudinal aberration becomes easy with oblique aberration.

And preferably, from wide-angle side during to the telescope end zoom, this second lens unit and the 3rd lens unit satisfy the following conditions expression formula.

0.3＜ΔG ₃/ΔG ₂＜1.2…(5)

Wherein,

Δ G ₂The variable quantity of position of the relative wide-angle side in position of representing the telescope end of this second lens unit,

Δ G ₃The variable quantity of position of the relative wide-angle side in position of representing the telescope end of the 3rd lens unit, and

Make the variation of object side become positive label.

Conditional expression (5) is the expression formula of preferred ratio of having pointed out the amount of movement of second lens unit and the 3rd lens unit.By constructing a kind of structure, feasible value is not higher than the higher limit in the conditional expression (5), and value is not less than the lower limit in the conditional expression (5), has reduced the deviation of amount of movement when second lens unit and the 3rd lens unit zoom, and has helped making that zoom-lens system diminishes.

And preferably, this first lens unit has the negative lens that the most close object is provided with, and satisfies the following conditions expression formula.

0.0＜(r _L11+r _L12)/(r _L11-r _L12)＜3.0…(6)

Wherein,

r _L11Represent in this first lens unit the most paraxial radius-of-curvature of the object side surface of this negative lens of close object, and

r _L12Represent in this first lens unit the most paraxial radius-of-curvature of the picture side surface of this negative lens of close object side.

Conditional expression (6) is the relevant expression formula of shape of the lens of close object in first lens unit with three-unit zoom lens system.By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (6), suppress the most close object in first lens unit lens surface curvature and suppress oblique aberration and become easy.

And by constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (6), can prevent negative lens with respect to the principal point (principal point) of negative lens excessively near object, and help making size decreases.

And preferably, when the lens sum was represented with N in this three-unit zoom lens system, this three-unit zoom lens system satisfied the following conditions expression formula.

5≤N≤8…(7)

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (7), helps cost cutting, and makes size decreases when the lens barrel retraction.

By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (7), becoming has optical property easily and guarantees zoom ratio.

And preferably, this second lens unit comprises the cemented lens of being made up of positive lens and negative lens, and the Abbe (Abbe) of this negative lens in this second lens unit number is less than the Abbe number of this positive lens in this second lens unit.

In order to revise the longitudinal chromatic aberration that is easy in the telescope end appearance, preferably, make the realization said structure, and give second lens unit achromatism.

And in three-unit zoom lens system according to the present invention, preferably, the lens of the 3rd lens unit add up to one.By constructing the 3rd lens unit, can reduce the thickness when the lens barrel retraction, and can suppress cost with lens.

And, in three-unit zoom lens system according to the present invention, preferably, two surfaces of this second lens unit, that is, the lens surface of close object and the lens surface of close image all be non-spherical surface.

By make second lens unit the most close object lens surface and the lens surface of close image become non-spherical surface, advantageously, advantageously revise from the spherical aberration of wide-angle side under all states of telescope end.

And, can use any the image in the above-mentioned three-unit zoom lens system to form lens as image pick-up device.In other words, preferably, make this image pick-up device become such image pick-up device, that is, it comprises: three-unit zoom lens system; And image pick-up element, this image pick-up element is arranged on the picture side of this three-unit zoom lens system, and the optical imagery that this three-unit zoom lens system is formed converts electric signal to, and this three-unit zoom lens system is in the above-mentioned three-unit zoom lens system any.Therefore, help making that device size diminishes.

And preferably, described image pick-up device comprises: image transitions portion, this image transitions portion will comprise that the electrical signal conversion of the distortion that causes because of this three-unit zoom lens system has become by the Flame Image Process correction picture signal of this distortion.By allowing the distortion of three-unit zoom lens system, help the size decreases of reducing number of lenses and making three-unit zoom lens system.

And, in image pick-up device according to the present invention, preferably, under the state of the wide-angle side of this three-unit zoom lens system, by optical axis with satisfy following conditions from the formed angle of chief ray of the maximum image height in the effective image pickup zone that is directed to this image pick-up element of this three-unit zoom lens system outgoing and express.

-40°＜EX(w)＜-11°…(8)

Wherein,

EX (w) expression is by optical axis with from the formed angle of chief ray of the maximum image height in the effective image pickup zone that is directed to this image pick-up element of this three-unit zoom lens system outgoing.

By use allow the to satisfy condition image pick-up element of size of emergence angle of expression formula (8), can give the 3rd lens unit with strong negative refractive power.

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (8), makes with the negative refractive power of abundance to give three lens unit easily, and help reducing the total length of three-unit zoom lens system, and has improved optical property.Therefore, be easily.

And, by constructing a kind of structure, make value be not less than the lower limit in the conditional expression (8), suppress emergence angle and become excessively big, and helped guaranteeing oblique incident ray.Therefore, be preferred.

When three-unit zoom lens system had focusing function, each that makes above-mentioned conditional expression all became a kind of structure under the state that the longest potential range focuses on.

Preferably, realize focusing on by moving the 3rd lens unit, in fact, this is reduction driving load easily.Certainly, can be the focus method that whole zoom-lens system is drawn out, maybe can be the focus method that first lens unit is drawn out.

Preferably, be provided with higher limit in conditional expression (1), and construct a kind of structure, the value of making is not higher than 8.0, and more preferably, this value is not higher than 5.5.

Preferably, in conditional expression (2), be provided with lower limit, and construct a kind of structure, make this value be not less than 0.05, and more preferably, this value is not less than 0.1.

Therefore, become and keep the intensity of lens easily.

Preferably, making higher limit is 0.5, and higher limit 0.3 more preferably.

Preferably, making the lower limit in the conditional expression (3) is 4, and lower limit 5 more preferably.

Preferably, making the higher limit in the conditional expression (3) is 7, and higher limit 6.5 more preferably.

Preferably, making the lower limit in the conditional expression (4) is 0.6, and lower limit 1.0 more preferably.

Preferably, making the higher limit in the conditional expression (4) is 1.7, and higher limit 1.6 more preferably.

Preferably, making the lower limit in the conditional expression (5) is 0.6, and lower limit 0.9 more preferably.

Preferably, making the higher limit in the conditional expression (5) is 1.1, and higher limit 1.05 more preferably.

Preferably, making the lower limit in the conditional expression (6) is 0.3, and lower limit 0.5 more preferably.

Preferably, making the higher limit in the conditional expression (6) is 1.5, and higher limit 1.0 more preferably.

Preferably, make the lower limit in the conditional expression (8) be-30.0 °, and lower limit-25.0 ° more preferably.

Preferably, make the higher limit in the conditional expression (8) be-12.0 °, and higher limit-15.0 ° more preferably.

Next, according to a second aspect of the invention three-unit zoom lens system is described.

In the present invention, three-unit zoom lens system has such basic structure, promptly, it comprises in order from object side: first lens unit with negative refractive power, second lens unit with positive refractive power, and the 3rd lens unit with negative refractive power, and from wide-angle side during to the telescope end zoom, distance between this first lens unit and this second lens unit narrows down, and the distance between this second lens unit and the 3rd lens unit changes, and this second lens unit is moving to object side during to the telescope end zoom from wide-angle side, and the 3rd lens unit and wide-angle side are relatively, and running fix is at the object side place of telescope end.

In such a way, be negative by the refractive power that makes first lens unit, help guaranteeing image angle, size is radially diminished, and reduction forms the lens unit number of zoom-lens system.

Minimizing on the lens unit number also helps the minimizing number of lenses.As a result, this causes lens frame attenuation and cost to reduce.

And, changing distance with first lens unit by second lens unit with positive refractive power, second lens unit is filled the post of expansion bend, and by increasing the convergent-divergent multiplying power moving to image-side from object side during to the telescope end zoom from wide-angle side.

And, by negative refractive power being given the 3rd lens unit, by at telescope end the 3rd lens unit is moved the effect of the increase that realizes the convergent-divergent multiplying power to object side with respect to wide-angle side.

By increasing the convergent-divergent multiplying power during to the telescope end zoom, in two lens units, that is, in second lens unit and the 3rd lens unit, can move the effect of sharing the increase that realizes the convergent-divergent multiplying power in a small amount by each lens unit from wide-angle side.As a result, can be so that the total length of zoom-lens system be less, and can keep good image quality.

Because the 3rd lens unit as the final lens unit has negative refractive power, the symmetry of the power profile of whole zoom-lens system becomes favourable.Therefore, with the negative refractive power balance of first lens unit.Thereby can not generate needs above aberration and picture planar curvature such as distortion.As a result, the longitudinal aberration that can provide balance and the tiltedly zoom-lens system of aberration.

Also comprise aperture diaphragm according to three-unit zoom lens system of the present invention, this aperture diaphragm be in this first lens unit as side and be in the object side of lens surface of the most close picture side of this second lens unit, and integrally move with this second lens unit.

By constructing a kind of structure in such a way, can suppress to be incident on the height on first lens unit, and make the lens unit size decreases radially of winning from axial ray.And, can be so that the size decreases radially of second lens unit, and help dimension reduction and guarantee the positive refractive power of second lens unit.And, can prevent that emergent pupil is too near image pick-up element.And, because aperture diaphragm integrally moves with second lens unit, thereby, can simply constructed driving mechanism, help simplified structure.

3.8＜f _t/f _w＜5.5…(21)

2.0＜β ₂(t)/β ₂(w)＜3.2…(22)

1.2＜β ₃(t)/β ₃(w)＜1.8…(23)

Wherein,

Conditional expression (21) is the expression formula of specifying zoom ratio, and preferably, by constructing a kind of structure, the lower limit that makes value be not less than in the conditional expression (21) is guaranteed zoom ratio.And by constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (21), help suppressing the convergent-divergent multiplying power load of second lens unit and the 3rd lens unit, and total length shortens.

Conditional expression (22) is the expression formula of specifying the convergent-divergent multiplying power load from the wide-angle side to the telescope end of second lens unit, and conditional expression (23) is the expression formula of specifying the convergent-divergent multiplying power load of the 3rd lens unit.

By not only convergent-divergent multiplying power load being given second lens unit but also is given the 3rd lens unit, can prevent that the convergent-divergent multiplying power load of second lens unit is extremely big, and amount of movement and aberration fluctuation when preventing convergent-divergent.

By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (22), can prevent easily that total length from increasing and the aberration that causes because of the excessive increase of the convergent-divergent multiplying power load of the 3rd lens unit fluctuates.

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (22), helps suppressing the convergent-divergent multiplying power load of second lens unit, and shortens total length.

By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (23), can reduce the convergent-divergent multiplying power load of second lens unit easily, and prevent that total length from increasing and the aberration during zoom fluctuates.

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (23), suppresses the convergent-divergent multiplying power load of the 3rd lens unit easily, and suppresses the amount of movement of the 3rd lens unit.

And, preferably, a kind of below satisfying according to three-unit zoom lens system of the present invention in the multiple structure.

In three-unit zoom lens system according to the present invention, preferably, the 3rd lens unit comprises the negative lens element with meniscus shape, and satisfies the following conditions expression formula.

-20＜(r _L31+r _L32)/(r _L31-r _L32)＜-1.0…(24)

Wherein,

r _L31The paraxial radius-of-curvature of representing the object side surface of this negative lens element in the 3rd lens unit, and

r _L32Represent in the 3rd lens unit this negative lens element the picture side surface paraxial radius-of-curvature and

Lens subassembly, this lens subassembly are the lens that only have two surfaces, that is, the incidence surface and the exit surface that contact with air in the zone that light passes, and this lens subassembly means single lens or cemented lens.

Conditional expression (24) is the expression formula of specifying the preferable shape of the negative lens element in the 3rd lens unit.By the expression formula that satisfies condition (24), help guaranteeing wide-angle side place particularly from the axle optical property.

By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (24), suppress the curvature of the incidence surface and the exit surface of negative lens element easily, and suppress to occur aberration.

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (24), and the incident angle that is incident on the light on the negative lens is diminished, and helps mainly suppressing oblique aberration.

And preferably, three-unit zoom lens system according to the present invention satisfies the following conditions expression formula.

3＜D _w/f _w＜8…(25)

0.3＜D _t/f _t＜1.8…(26)

Wherein,

This total optical axis length be this three-unit zoom lens system pass through to be added into the length that optical axis thickness was obtained from the exit surface of the lens of the through the most close image of the incidence surface of the lens of close object with the back focus that the air characteristic chamber length is expressed.

Conditional expression (25) and (26) are the expression formulas of specifying the preferred overall length of three-unit zoom lens system.By constructing a kind of structure, the value of making is not higher than the higher limit in conditional expression (25) and (26), helps attenuation in use.And, by constructing a kind of structure, make value be not less than the lower limit in conditional expression (25) and (26), suppress the refractive power of each lens unit easily, and reduction longitudinal aberration and oblique aberration.

0.3＜ΔG ₃/ΔG ₂＜1.2…(27)

Wherein,

Make the variation of object side become positive label.

Conditional expression (27) is the expression formula of preferred ratio of the amount of movement of expression second lens unit and the 3rd lens unit.By constructing a kind of structure, feasible value is not higher than the higher limit in the conditional expression (27), and value is not less than the lower limit in the conditional expression (27), reduced the deviation on the amount of movement when second lens unit and the 3rd lens unit zoom, and helped making that zoom-lens system diminishes.

And preferably, this first lens unit has the negative lens of close object side, and satisfies the following conditions expression formula.

0.0＜(r _L11+r _L12)/(r _L11-r _L12)＜3.0…(28)

Wherein,

r _L11Represent in this first lens unit the most paraxial radius-of-curvature of the object side surface of this negative lens of close object side, and

Conditional expression (28) is the relevant expression formula of shape of the lens of close object in first lens unit with three-unit zoom lens system.By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (28), suppress the curvature of the lens surface of the most close object side in first lens unit easily, and suppress oblique aberration.

And by constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (28), can prevent negative lens with respect to the principal point of negative lens excessively near object, and help making size decreases.

5≤N≤8…(29)

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (29), helps cost cutting, and makes size decreases when the lens barrel retraction.

By constructing a kind of structure, make value be not less than the lower limit in the conditional expression (29), have optical property easily and guarantee zoom ratio.

And preferably, this second lens unit comprises the cemented lens of being made up of positive lens and negative lens, and the Abbe number of this negative lens in this second lens unit is less than the Abbe number of this positive lens in this second lens unit.In order to revise the longitudinal chromatic aberration that is easy in the wide-angle side appearance, preferably, realize said structure, and give second lens unit achromatism.

And, in three-unit zoom lens system according to the present invention, preferably, two surfaces of this second lens unit, that is, the lens surface of close object and the lens surface of close image all be non-spherical surface.By make second lens unit the most close object lens surface and the lens surface of close image become non-spherical surface, advantage is the spherical aberration of advantageously revising under all states of the through telescope end of wide-angle side.

And preferably, described image pick-up device comprises image transitions portion, and this image transitions portion will comprise that this electrical signal conversion of the distortion that causes because of this three-unit zoom lens system has become through the Flame Image Process correction picture signal of this distortion.By allowing the distortion of three-unit zoom lens system, help the size decreases of reducing number of lenses and making three-unit zoom lens system.

And, in image pick-up device according to the present invention, preferably, under the state of the wide-angle side of this three-unit zoom lens system, satisfy the following conditions expression formula by optical axis with from the formed angle of chief ray of the maximum image height in the effective image pickup zone that is directed to this image pick-up element of this three-unit zoom lens system outgoing.

-40°＜EX(w)＜-11°…(30)

Wherein,

By use allow the to satisfy condition image pick-up element of size of emergence angle of expression formula (30), can give the 3rd lens unit with strong negative refractive power.

By constructing a kind of structure, the value of making is not higher than the higher limit in the conditional expression (30), with the negative refractive power of abundance gives three lens unit easily, and help reducing the total length of three-unit zoom lens system, and has improved optical property.Therefore, be easily.

And, by constructing a kind of structure, make value be not less than the lower limit in the conditional expression (30), suppress emergence angle and become excessively big, and help guaranteeing oblique incident ray.Therefore, be preferred.

When three-unit zoom lens system has focusing function, in the above-mentioned conditional expression each all is arranged under the state that the longest potential range focuses on.

Preferably, realize focusing on by moving the 3rd lens unit, because so easy reduction drives load.Certainly, can be the focus method that whole zoom-lens system is drawn out, maybe can be the focus method that first lens unit is drawn out.

Preferably, making the lower limit in the conditional expression (22) is 2.1, and lower limit 2.2 more preferably.

Preferably, making the higher limit in the conditional expression (22) is 3.0, and higher limit 2.8 more preferably.

Preferably, making the lower limit in the conditional expression (23) is 1.25, and lower limit 1.3 more preferably.

Preferably, making the higher limit in the conditional expression (23) is 1.75, and higher limit 1.8 more preferably.

Preferably, making the lower limit in the conditional expression (24) is-10, and lower limit-6 more preferably.

Preferably, making the higher limit in the conditional expression (24) is-2.0, and higher limit-3.0 more preferably.

Preferably, making the lower limit in the conditional expression (25) is 4, and lower limit 5 more preferably.

Preferably, making the higher limit in the conditional expression (25) is 7, and higher limit 6.5 more preferably.

Preferably, making the lower limit in the conditional expression (26) is 0.6, and lower limit 1.0 more preferably.

Preferably, making the higher limit in the conditional expression (26) is 1.7, and higher limit 1.6 more preferably.

Preferably, making the lower limit in the conditional expression (27) is 0.6, and lower limit 0.9 more preferably.

Preferably, making the higher limit in the conditional expression (27) is 1.1, and higher limit 1.05 more preferably.

Preferably, making the lower limit in the conditional expression (28) is 0.3, and lower limit 0.5 more preferably.

Preferably, making the higher limit in the conditional expression (28) is 1.5, and higher limit 1.0 more preferably.

Preferably, make the lower limit in the conditional expression (30) be-30.0 °, and lower limit-25.0 ° more preferably.

Preferably, make the higher limit in the conditional expression (30) be-12.0 °, and higher limit-15.0 ° more preferably.

Preferably, any a plurality of conditional expression is all satisfied in above-mentioned each invention simultaneously.And, about each conditional expression, only define higher limit and lower limit in the numerical range that is in more restrictive condition expression formulas.And, can the above-mentioned various structures of combination in any.

Below, with reference to accompanying drawing, the exemplary embodiment of three-unit zoom lens system according to the present invention and image pick-up device is elaborated.Yet, the invention is not restricted to following embodiment.

Each all is to have three-unit zoom lens system negative, positive and the negative refractive power type for following embodiment, has good optical property, wherein, realizes about 4 times high zoom ratios, and guarantees 38 ° or higher wide-angle side half image angle.And it is a kind of such zoom-lens system, and is wherein, near wide-angle side, at the 3rd lens unit place with negative refractive power, along the direction refraction away from optical axis, radially less with the size of optical axis direction from axial ray.

From a plurality of embodiments of first embodiment to the, five embodiments, the effective image pickup zone under the full zoom state is a rectangle and constant.

Below, the numerous embodiments from first embodiment to the, five embodiments according to three-unit zoom lens system of the present invention is described.Figure 1A shows the lens sectional view of the wide-angle side when the infinity object point focuses on (Figure 1A, Fig. 2 A, Fig. 3 A, Fig. 4 A and Fig. 5 A), middle focal length state (Figure 1B, Fig. 2 B, Fig. 3 B, Fig. 4 B and Fig. 5 B) and telescope end (Fig. 1 C, Fig. 2 C, Fig. 3 C, Fig. 4 C and Fig. 5 C) from the numerous embodiments of first embodiment to the, five embodiments to Fig. 5 C.At Figure 1A in Fig. 5 C, G1 represents first lens unit, G2 represents second lens unit, S represents aperture diaphragm, and G3 represents the 3rd lens unit, and F represents to form the parallel flat of optical low-pass filter, in this parallel flat, be coated with the ultrared wavelength zone of restriction restriction coating, C represents the parallel flat of being made by carbon glass of electronic image pickup device, and I represents as the plane.The multilayer film that is used for the wavelength-limited district can be applied to the surface of carbon glass C.And, can make carbon glass C have the optical low-pass filter effect.

And in each embodiment, aperture diaphragm S integrally moves with the second lens unit G2.And each numeric data is the data under the state of the object place at infinite distance place focusing (when focusing on).Long measure at each value is mm, and angular unit degree of being (°).All the lens unit of close image realizes by moving in focusing in each embodiment.In other words, focus on by moving the 3rd lens unit and realize, and realize by move the 3rd lens unit G3 to image to the focusing operation of short distance object point apart from object point from long.And the zoom data are values that wide-angle side (WE), middle focal length state (ST) and telescope end (TE) are located.

Shown in Figure 1A, Figure 1B and Fig. 1 C, the zoom-lens system of first embodiment comprises in order from object side: have the first lens unit G1, the aperture diaphragm S of negative refractive power, the 3rd lens unit G3 that has the second lens unit G2 of positive refractive power and have negative refractive power.

From wide-angle side during to the telescope end zoom, the first lens unit G1 moves towards object side after the picture side shifting.Second lens unit only moves towards object side.The 3rd lens unit G3 only moves towards object side.

From object side in order, the first lens unit G1 comprises negative biconcave lens and the positive meniscus shaped lens that has towards the nonreentrant surface of object side.Second lens unit comprises by having towards the positive meniscus shaped lens of the nonreentrant surface of object side, having towards the negative meniscus lens of the nonreentrant surface of object side and the cemented lens that positive biconvex lens is formed.The 3rd lens unit G3 comprises the negative meniscus lens that have towards the nonreentrant surface of picture side.

Non-spherical surface is used for five surfaces, that is the object side surface of the picture side surface of the object side surface of two surfaces of the negative biconcave lens among the first lens unit G1, the positive meniscus shaped lens among the second lens unit G2 and positive biconvex lens and the negative meniscus lens among the 3rd lens unit G3.

To shown in Fig. 2 C, the zoom-lens system in second embodiment comprises in order from object side as Fig. 2 A, Fig. 2 B: have the first lens unit G1, the aperture diaphragm S of negative refractive power, the 3rd lens unit G3 that has the second lens unit G2 of positive refractive power and have negative refractive power.

From wide-angle side during to the telescope end zoom, the first lens unit G1 moves towards object side after the picture side shifting.The second lens unit G2 only moves towards object side.The 3rd lens unit G3 only moves towards object side.

From object side in order, the first lens unit G1 comprises negative biconcave lens and positive biconvex lens.The second lens unit G2 comprises cemented lens and the positive biconvex lens that positive biconvex lens and negative biconcave lens are formed.The 3rd lens unit G3 comprises the negative meniscus lens that have towards the nonreentrant surface of picture side.

Non-spherical surface is used for three surfaces, that is, and the picture side surface of the negative biconcave lens among the first lens unit G1, the object side surface of the positive biconvex lens of object side among the second lens unit G2 and the picture side surface of the positive biconvex lens of picture side.

Shown in Fig. 3 A, Fig. 3 B and Fig. 3 C, the zoom-lens system in the 3rd embodiment comprises in order from object side: have the first lens unit G1, the aperture diaphragm S of negative refractive power, the 3rd lens unit G3 that has the second lens unit G2 of positive refractive power and have negative refractive power.

From object side in order, the first lens unit G1 comprises negative biconcave lens and the positive meniscus shaped lens that has towards the nonreentrant surface of object side.The second lens unit G2 comprises by having towards the positive meniscus shaped lens of the nonreentrant surface of object side, having towards the negative meniscus lens of the nonreentrant surface of object side and the cemented lens that positive biconvex lens is formed.The 3rd lens unit G3 comprises the negative meniscus lens that have towards the nonreentrant surface of picture side.

Shown in Fig. 4 A, Fig. 4 B and Fig. 4 C, the zoom-lens system in the 4th embodiment comprises in order from object side: have the first lens unit G1, the aperture diaphragm S of negative refractive power, the 3rd lens unit G3 that has the second lens unit G2 of positive refractive power and have negative refractive power.

From object side in order, the first lens unit G1 comprises negative biconcave lens and the positive meniscus shaped lens that has towards the nonreentrant surface of object side.The second lens unit G2 comprises by positive biconvex lens and has the cemented lens of forming towards the negative meniscus lens of the nonreentrant surface that looks like side.The 3rd lens unit G3 comprises the negative meniscus lens that have towards the nonreentrant surface of picture side.

Non-spherical surface is used for four surfaces, that is, the picture side surface of the object side surface of the picture side surface of the negative biconcave lens among the first lens unit G1, the positive biconvex lens among the second lens unit G2 and negative meniscus lens and the object side surface of the negative meniscus lens among the 3rd lens unit G3.

Shown in Fig. 5 A, Fig. 5 B and Fig. 5 C, the zoom-lens system in the 5th embodiment comprises in order from object side: have the first lens unit G1, the aperture diaphragm S of negative refractive power, the 3rd lens unit G3 that has the second lens unit G2 of positive refractive power and have negative refractive power.

From object side in order, the first lens unit G1 comprises negative biconcave lens and the positive meniscus shaped lens that has towards the nonreentrant surface of object side.The second lens unit G2 comprises by having towards the positive meniscus shaped lens of the nonreentrant surface of object side, having towards the negative meniscus lens of the nonreentrant surface of object side and cemented lens that positive biconvex lens is formed and have positive meniscus shaped lens towards the nonreentrant surface of object side.The 3rd lens unit G3 comprises negative biconcave lens and the positive meniscus shaped lens that has towards the nonreentrant surface of object side.

Non-spherical surface is used for five surfaces, promptly, the picture side surface of two surfaces of the negative biconcave lens among the first lens unit G1, the object side surface of the positive meniscus shaped lens of object side among the second lens unit G2 and positive biconvex lens, and the object side surface of the negative biconcave lens among the 3rd lens unit G3.

Show the numeric data of the respective embodiments described above below.Except above-mentioned symbol, f represents the focal length of whole zoom-lens system, F _NOExpression F number, ω represents half image angle, and WE represents wide-angle side, and ST represents intermediateness, and TE represents telescope end, r ₁, r ₂The radius-of-curvature of representing each lens surface, d ₁, d ₂... in two lens of each expression between distance, n _D1, n _D2... in each represent the refractive index at the d line of each lens, and v _D1, v _D2... in each represent the Abbe number of each lens.

The total length of lens combination described later is by back focus being added into from first lens surface length that distance obtained of lens surface to the last.BF (back focus) is to carrying out air expressed unit when converting from last lens surface up to paraxial distance as the plane.

Be the optical axis of (direction) just if x is made as with the light direct of travel, y is made as direction with light shaft positive cross, then be described by the shape of following expression to non-spherical surface.

x＝(y ²/r)/[1+{1-(K+1)(y/r) ²} ^1/2]+A ₄y ⁴+A ₆y ⁶+A ₈y ⁸+A ₁₀y ¹⁰+A ₁₂y ¹²

Wherein, r represents paraxial radius-of-curvature, and K represents circular cone coefficient, A ₄, A ₆, A ₈, A ₁₀And A ₁₂The non-spherical surface coefficient of representing quadravalence, six rank, eight rank, ten rank and ten second orders respectively.And, in the non-spherical surface coefficient, " e-n " (wherein, n is an integer) expression " 10-n ".

And " * " means the surface is non-spherical surface, is aperture diaphragm and " S " means the surface, is diaphragm and " FS " means the surface.

Embodiment 1

The mm of unit

Surface data

Surface number r d nd vd

1 ^* -113.961 0.70 1.88300 40.76

2 ^* 5.940 1.65

3 10.858 1.73 1.84666 23.78

4 50.171 is variable

5(S) ∞ 0.00

6 ^* 4.509 2.40 1.51633 64.14

7 10.100 0.54 1.90366 31.32

8 3.983 2.15 1.62263 58.16

9 ^*-24.449 is variable

10 ^* -3.808 1.00 1.497008 1.54

11-5.865 is variable

12 ∞ 0.50 1.53996 59.45

13 ∞ 0.50

14 ∞ 0.49 1.51633 64.14

15 ∞ 0.58

Picture plane (optical receiving surface)

Asphericity coefficient

First surface

K＝0.000，A4＝-5.53177e-04，A6＝3.25017e-05，A8＝-8.64611e-07，A10＝8.14308e-09

Second surface

K＝0.000，A4＝-1.03578e-03，A6＝2.37354e-05，A8＝-4.40077e-07，A10＝-2.03801e-08

The 6th surface

K＝-0.246，A4＝-1.98445e-04，A6＝-1.40006e-05，A8＝1.28259e-06

The 9th surface

K＝13.738，A4＝1.07699e-03，A6＝1.12355e-05，A8＝1.16855e-06，A10＝6.46670e-07

The tenth surface

K＝-0.461，A4＝-7.07395e-04，A6＝-5.05995e-05，A8＝-6.19626e-07，A10＝-1.06047e-07

The group focal length

f1＝-12.40 f2＝9.28 f3＝-26.06

The zoom data

WE ST TE

IH 3.84 3.84 3.84

F(mm) 5.80 11.50 22.20

Fno. 2.87 3.95 6.00

2ω(°) 76.60 37.70 19.69

BF 3.03 7.13 15.30

Total length of lens 36.66 30.71 33.96

d4 16.69 6.44 1.50

d9 6.77 6.98 6.99

d11 1.30 5.39 13.58

Embodiment 2

The mm of unit

Surface data

Surface number r d nd vd

1 -23.597 0.70 1.88300 40.76

2 ^* 6.226 1.43

3 12.104 1.52 1.84666 23.78

4-450.803 is variable

5(S) ∞ 0.00

6 ^* 5.814 2.40 1.61772 49.81

7 -10.102 0.50 2.00069 25.46

8 28.851 0.25

9 8.468 2.15 1.51742 52.43

10 ^*-12.126 is variable

11 -3.573 1.00 1.61800 63.33

12-6.653 is variable

13 ∞ 0.84 1.53996 59.45

14 ∞ 0.26

15 ∞ 0.49 1.51633 64.14

16 ∞ 0.58

Picture plane (optical receiving surface)

Asphericity coefficient

Second surface

K＝0.000，A4＝-6.75522e-04，A6＝1.79460e-05，A8＝-1.93173e-06，A10＝4.14591e-08

The 6th surface

K＝-0.452，A4＝-2.82467e-05，A6＝1.96831e-05，A8＝2.08520e-07

The tenth surface

K＝0.000，A4＝1.06303e-03，A6＝3.27588e-05，A8＝-2.57123e-06，A10＝2.03117e-07

The group focal length

f1＝-11.15 f2＝8.05 f3＝-14.26

The zoom data

WE ST TE

IH 3.84 3.84 3.84

F(mm) 5.80 11.50 22.20

Fno. 2.71 3.85 6.00

2ω(°) 76.82 37.55 19.64

BF 3.01 7.11 14.95

Total length of lens 31.12 27.42 31.44

d4 12.16 4.30 0.49

d10 6.01 6.06 6.06

d12 1.30 5.40 13.24

Embodiment 3

The mm of unit

Surface data

Surface number r d nd vd

1 ^* -62.729 0.70 1.88300 40.76

2 ^* 5.852 1.51

3 11.451 1.66 2.00069 25.46

4 56.559 is variable

5(S) ∞ 0.00

6 ^* 4.483 2.40 1.51633 64.14

7 11.667 0.62 1.90366 31.32

8 4.172 2.15 1.62263 58.16

9 ^*-23.523 is variable

10 ^* -4.173 1.00 1.49700 81.54

11-6.653 is variable

12 ∞ 0.50 1.53996 59.45

13 ∞ 0.50

14 ∞ 0.49 1.51633 64.14

15 ∞ 0.58

Picture plane (optical receiving surface)

Asphericity coefficient

First surface

K＝0.000，A4＝-5.96485e-04，A6＝3.58482e-05，A8＝-9.13819e-07，A10＝7.87055e-09

Second surface

K＝0.000，A4＝-1.17758e-03，A6＝2.71790e-05，A8＝-4.34015e-07，A10＝-2.58636e-08

The 6th surface

K=-0.271, A4=-1.55770e-04, A6=-1.24411e-05, A8=1.56677e-06 the 9th surface

K＝5.238，A4＝1.15790e-03，A6＝1.61626e-05，A8＝1.90077e-06，A10＝7.47798e-07

The tenth surface

K＝-0.261，A4＝-2.50820e-04，A6＝-2.61630e-05，A8＝-1.29687e-06，A10＝4.23771e-08

The group focal length

f1＝-12.65 f2＝9.29 f3＝-26.01

The zoom data

WE ST TE

IH 3.84 3.84 3.84

F(mm) 5.80 11.50 22.20

Fno. 2.89 3.95 6.00

2ω(°) 76.57 37.67 19.67

BF 3.03 7.10 15.13

Total length of lens 36.66 30.49 33.49

d4 16.94 6.53 1.50

d9 6.65 6.82 6.82

d11 1.30 5.37 13.40

Embodiment 4

The mm of unit

Surface data

Surface number r d nd vd

1 -44.119 0.70 1.88300 40.76

2 ^* 6.743 2.11

3 13.925 1.48 2.00069 25.46

4 67.476 is variable

5(S) ∞ 0.00

6 ^* 3.809 3.42 1.49700 81.54

7 -13.130 1.14 2.00069 25.46

8 ^* -19.141 0.10

9 (FS) ∞ is variable

10 ^*? -4.878 0.70 1.90366 31.32

11-8.942 is variable

12 ∞ 0.50 1.53996 59.45

13 ∞ 0.50

14 ∞ 0.49 1.51633 64.14

15 ∞ 0.58

Picture plane (optical receiving surface)

Asphericity coefficient

Second surface

K＝0.000，A4＝-3.98131e-04，A6＝5.35977e-06，A8＝-5.75098e-07，A?10＝6.89098e-09

The 6th surface

K＝-0.272，A4＝-5.88555e-07，A6＝5.16624e-06，A8＝6.09708e-07

The 8th surface

K＝0.000，A4＝4.38763e-04，A6＝-3.60378e-05，A8＝-1.51518e-06

The tenth surface

K＝2.233，A4＝3.88532e-04，A6＝-7.90831e-06，A8＝-2.22240e-05，A10＝2.80129e-06

The group focal length

f1＝-13.01 f2＝7.29 f3＝-12.93

The zoom data

WE ST TE

IH 3.84 3.84 3.84

F(mm) 5.80 11.50 22.20

Fno. 2.95 4.01 6.00

2ω(°) 76.55 37.54 19.63

BF 2.74 6.51 13.56

Total length of lens 36.66 30.45 32.82

d4 17.07 5.95 0.49

d9 1.56 1.56 1.57

d11 6.64 11.02 19.21

Embodiment 5

The mm of unit

Surface data

Surface number r d nd vd

1 ^* -111.266 0.70 1.88300 40.76

2 ^* 5.909 1.26

3 10.112 1.96 1.84666 23.78

4 50.504 is variable

5(S) ∞ 0.00

6 ^* 4.481 2.40 1.51633 64.14

7 11.342 0.50 1.90366 31.32

8 4.207 2.15 1.62263 58.16

9 ^* -252.084 0.14

10 9.356 1.25 1.49700 81.54

11 18.335 is variable

12 ^* -5.905 0.70 1.49700 81.54

13 30.761 0.37

14 9.095 1.00 1.51823 58.90

15 98.713 is variable

16 ∞ 0.50 1.53996 59.45

17 ∞ 0.50

18 ∞ 0.49 1.51633 64.14

19 ∞ 0.58

Picture plane (optical receiving surface)

Asphericity coefficient

First surface

K＝0.000，A4＝-6.02756e-04，A6＝3.47805e-05，A8＝-9.06023e-07，A10＝8.53020e-09

Second surface

K＝0.000，A4＝-1.05771e-03，A6＝2.49321e-05，A8＝-5.65594e-07，A10＝-1.63882e-08

The 6th surface

K＝-0.246，A4＝-1.27449e-04，A6＝-7.86582e-06，A8＝1.17400e-06

The 9th surface

K＝5390.316，A4＝1.01581e-03，A6＝3.65454e-05，A8＝1.66136e-06，A10＝7.32860e-07

The 12 surface

K＝0.385，A4＝-1.03478e-03，A6＝-3.03171e-06，A8＝1.20709e-05，A10＝9.65850e-07

The group focal length

f1＝-12.77 f2＝8.90 f3＝-22.03

The zoom data

WE ST TE

IH 3.84 3.84 3.84

F(mm) 5.80 11.50 22.20

Fno. 2.91 3.98 6.00

2ω(°) 76.35 38.01 19.75

BF 2.74 6.51 13.56

Total length of lens 36.66 30.45 32.82

d4 16.74 6.52 1.50

d11 4.75 4.98 5.32

d15 1.00 4.78 11.83

From the numerous embodiments of the 6th embodiment to the ten embodiments, used the zoom-lens system from these embodiments of first embodiment to the, five embodiments respectively.Be to use embodiment from these embodiments of the 6th embodiment to the ten embodiments, and effectively the shape in image pickup zone changes when zoom with the image pick-up device of electric mode correction distortion.Therefore, these embodiments are different from the embodiment of image height and image angle correspondence under the zoom state.

Image pick-up device is to comprise half image angle (half image angle) ω with 34 ° and at the device of the bigger zoom-lens system of wide-angle side.

From these embodiments of the 6th embodiment to the ten embodiments, at the tube distortion back record and the display image that occur in wide-angle side with electric mode correction.

In the zoom-lens system of these embodiments, the tube distortion appears at the wide-angle side place of rectangle photoelectricity conversion table face.Yet, suppressed distortion in telescope end and close middle focal length state appearance.

For with electric mode correction distortion, make effective image pickup zone be tubular in wide-angle side, and rectangular at middle focal length state or telescope end place.

And the image transitions according to Flame Image Process is stood in the effective image pickup zone that sets in advance, and is converted into the rectangular image information of having reduced distortion.

Construct a kind of structure, make the maximum image height IH of wide-angle side _wBecome less than the maximum image height IH of middle focal length state _s, and the image height IH of telescope end _t

From these embodiments of the 6th embodiment to the ten embodiments, construct a kind of structure, make in wide-angle side, equal along the effective length of the shorter side direction in image pickup zone along the length of the shorter side direction on opto-electronic conversion surface, and effective image pickup zone is set, makes and after Flame Image Process, keep approximately-3% distortion.Certainly, can construct a kind of structure, feasible cylindrical area less than image is converted into the image that is set as record and reproduction as this image of the rectangular shape in effective image pickup zone.

The zoom-lens system of the 6th embodiment has the structure with the similar of the zoom-lens system of first embodiment.

The zoom-lens system of the 7th embodiment has the structure with the similar of the zoom-lens system of second embodiment.

The zoom-lens system of the 8th embodiment has the structure with the similar of the zoom-lens system of the 3rd embodiment.

The zoom-lens system of the 9th embodiment has the structure with the similar of the zoom-lens system of the 4th embodiment.

The zoom-lens system of the tenth embodiment has the structure with the similar of the zoom-lens system of the 5th embodiment.

Below, show the image height among the embodiment 6 and the data of total image angle.

The zoom data

WE ST TE

F(mm) 5.80 11.50 22.20

Fno. 2.87 3.95 6.00

2ω(°) 68.64 37.70 19.69

IH 3.46 3.84 3.84

Below, the image height among the embodiment 7 and the data of total image angle are shown.

The zoom data

WE ST TE

F(mm) 5.80 11.50 22.20

Fno. 2.71 3.85 6.00

2ω(°) 68.63 37.55 19.64

IH 3.45 3.84 3.84

Below, the image height among the embodiment 8 and the data of total image angle are shown.

The zoom data

WE ST TE

F(mm) 5.80 11.50 22.20

Fno. 2.89 3.95 6.00

2ω(°) 68.63 37.67 19.67

IH 3.46 3.84 3.84

Below, the image height among the embodiment 9 and the data of total image angle are shown.

The zoom data

WE ST TE

F(mm) 5.80 11.50 22.20

Fno. 2.95 4.01 6.00

2ω(°) 68.63 37.54 19.63

IH 3.45 3.84 3.84

Below, the image height among the embodiment 10 and the data of total image angle are shown.

The zoom data

WE ST TE

F(mm) 5.80 11.50 22.20

Fno. 2.91 3.98 6.00

2ω(°) 68.64 38.01 19.75

IH 3.46 3.84 3.84

Fig. 6 A shows the aberration diagram when the infinity object point focuses on according to first embodiment to the, five these embodiments of embodiment to Figure 10 C.In these aberration diagrams, Fig. 6 A, Fig. 7 A, Fig. 8 A, Fig. 9 A and Figure 10 A show spherical aberration (sphericalabrration), astigmatism, distortion and the convergent-divergent ratio chromatism, in wide-angle side respectively, Fig. 6 B, Fig. 7 B, Fig. 8 B, Fig. 9 B and Figure 10 B show spherical aberration, astigmatism, distortion and the convergent-divergent ratio chromatism, at the middle focal length state respectively, and Fig. 6 C, Fig. 7 C, Fig. 8 C, Fig. 9 C and Figure 10 C show spherical aberration, astigmatism, distortion and convergent-divergent ratio chromatism, at telescope end respectively.In each figure, ' ω ' represents half image angle.

Below, provide conditional expression (1) in these embodiments to the value of (8).

Embodiment 1 embodiment 2 embodiment 3 embodiment 4 embodiment 5

(1)f _t/f _w 3.83 3.83 3.83 3.83 3.83

(2)d _G3/f _w 0.17 0.17 0.17 0.12 0.36

(3)D _w/f _w 6.32 5.37 6.32 6.32 6.32

(4)D _t/f _t 1.53 1.42 1.51 1.47 1.48

(5)ΔG ₃/ΔG ₂?0.98 1.00 0.99 1.00 0.95

(6)(r _L11+r _L12)/(r _L11-r _L12)

0.90 0.58 0.83 0.73 0.90

(7)N 6 6 6 5 8

(8)EX(w) -17.96 -20.85 -18.27 -17.34 -17.31

Embodiment 6 embodiment 7 embodiment 8 embodiment 9 embodiment 10

(1)f _t/f _w 3.83 3.83 3.83 3.83 3.83

(2)d _G3/f _w 0.17 0.17 0.17 0.12 0.36

(3)D _w/f _w 6.32 5.37 6.32 6.32 6.32

(4)D _t/f _t 1.53 1.42 1.51 1.47 1.48

(5)ΔG ₃/ΔG ₂?0.98 1.00 0.99 1.00 0.95

(6)(r _L11+r _L12)/(r _L11-r _L12)

0.90 0.58 0.83 0.73 0.90

(7)N 6 6 6 5 8

(8)EX(w) -16.29 -18.89 -16.55 -15.65 -16.30

Below, provide conditional expression (21) in the embodiment to the value of (30).

Embodiment 1 embodiment 2 embodiment 3 embodiment 4 embodiment 5

(21)f _t/f _w 3.83 3.83 3.83 3.83 3.83

(22)β ₂(t)/β ₂(w) 2.75 2.34 2.76 2.44 2.73

(23)β ₃(t)/β ₃(w) 1.39 1.64 1.39 1.54 1.40

(24)(r _L31+r _L32)/(r _L31-r _L32)

-4.70 -3.32 -4.37 -3.40 -

(25)D _w/f _w 6.32 5.37 6.32 6.32 6.32

(26)D _t/f _t 1.53 1.42 1.51 1.47 1.48

(27)ΔG ₃/ΔG ₂ 0.98 1.00 0.99 1.00 0.95

(28)(r _L11+r _L12)/(r _L11-r _L12)

0.90 0.58 0.83 0.73 0.90

(29)N 6 6 6 5 8

(30)EX(w) -17.96 -20.85 -18.27 -17.34 -17.31

Embodiment 6 embodiment 7 embodiment 8 embodiment 9 embodiment 10

(21)f _t/f _w 3.83 3.83 3.83 3.83 3.83

(22)β ₂(t)/β ₂(w) 2.75 2.34 2.76 2.44 2.73

(23)β ₃(t)/β ₃(w) 1.39 1.64 1.39 1.54 1.40

(24)(r _L31+r _L32)/(r _L31-r _L32)

-4.70 -3.32 -4.37 -3.40 -

(25)D _w/f _w 6.32 5.37 6.32 6.32 6.32

(26)D _t/f _t 1.53 1.42 1.51 1.47 1.48

(27)ΔG ₃/ΔG ₂ 0.98 1.00 0.99 1.00 0.95

(28)(r _L11+r _L12)/(r _L11-r _L12)

0.90 0.58 0.83 0.73 0.90

(29)N 6 6 6 5 8

(30)EX(w) -16.29 -18.89 -16.55 -15.65 -16.30

In addition, in order to prevent ghost image and hot spot (flare), in general, anti-reflection coating is applied to the surface that contacts with air of lens.

On the other hand, at the adhesive surface place of cemented lens, the refractive index of bonding agent is far above the refractive index of air.Therefore, in many cases, originally reflectivity is exactly the level of signal layer coating or lower, thereby, under few cases, apply coating.Yet, when using anti-reflection coating energetically even using it for adhesive surface, can further reduce ghost image and hot spot, and obtain better pictures.

Specifically, recently, the glass material that will have high index of refraction is widely used in the optical system of video camera, to have good effect in the aberration correction.Yet when the glass material that will have high index of refraction was used as cemented lens, the reflection at adhesive surface place became and can not ignore.In this case, it is effective especially to apply anti-reflection coating on adhesive surface.

Opening flat 2-27301, spy the Japanese Patent Application spy opens 2001-324676, spy and opens the effective application that discloses the adhesive surface coating in No. 7116482,2005-92115 and the United States Patent (USP).In these patent documentations, cemented lens surface coating in first lens unit of positive front end zoom-lens system has been described, and with these patent documentations in disclosed identical cemented lens surface coating can realize being used for the cemented lens surface with first lens unit of positive refractive power of the present invention.

As the coating material that will use, according to the refractive index of adhesion material with as the refractive index of the lens on basis, can select rightly to have relative high index such as Ta ₂O ₅, TiO ₂, Nb ₂O ₅, ZrO ₂, HfO ₂, CeO ₂, SnO ₂, In ₂O ₃, ZnO and Y ₂O ₃Coating material and have relatively low refractive index such as MgF ₂, SiO ₂, Al ₂O ₃Coating material, and they are arranged to satisfy the film thickness of phase condition.

Nature, similar with the lip-deep coating that contacts with air of lens, can also be set as laminated coating to the coating on the adhesive surface.By making up film thickness and the coating material that is no less than two-layer multilayer film rightly, can further reduce reflectivity, and can control spectral signature and corner characteristics.

And, should be understood that for the adhesive surface of other lens beyond the lens in first lens unit, based on similar thought, it also is effective applying coating on adhesive surface.

(distortion is revised)

In addition, when using zoom-lens system of the present invention, carry out numeral correction to pattern distortion in electric mode.Below, the key concept that the pattern distortion numeral is revised describes.

For example, as shown in figure 11, be the center with the intersection point on optical axis and image pickup plane, the radius that connects in the longer side fixing and effectively image pickup plane is the convergent-divergent multiplying power of the circumference (image height) of the circle of R, and this circumference as the basic benchmark of revising.Next, move each point on the circumference (image height) of other any radius r (ω) beyond the radius R along general radial direction, and carry out correction by becoming at radius to move on the r ' concentric circles (ω).

For example, in Figure 11, be the center of the circle of R towards radius, will be positioned at any radius r of the inboard of this circle ₁Some P on the circumference (ω) ₁Moving to the radius that will revise is r ₁Some P on ' (ω) the circumference ₂And, the direction at center of the circle of R towards (edge) away from radius, will be positioned at any radius r in the outside of this circle ₂Some Q on the circumference (ω) ₁Moving to the radius that will revise is r ₂Some Q on ' (ω) the circumference ₂

Here, r ' (ω) can be expressed as follows.

r′(ω)＝α·f·tanω(0≤α≤1)

Wherein, ω is half image angle of object, and f is the focal length of imaging optical system (zoom-lens system among the present invention).

Here, when handle and radius be that the corresponding desirable image height of circle (image height) of R is when being made as Y, then

α＝R/Y＝R/(f·tanω)。

It is desirable to, optical system is rotational symmetric with respect to optical axis.In other words, distortion is also to occur with respect to the rotational symmetric mode of optical axis.Thereby, as mentioned above, for situation with electric mode correction optical distortion, if can carry out correction in the following manner, then be considered to favourable with regard to data volume and calculated amount: with the optical axis of reproduced image and the intersection point on image pickup plane is the center, the radius that connects in the longer side fixing and effectively image pickup plane is the convergent-divergent multiplying power of the circumference (image height) of the circle of R, and move each point on the circumference (image height) of the radius r (ω) beyond the radius R along general radial direction, and become on the r ' concentric circles (ω) at radius and to move.

In addition, the time point place when electronic image pickup device captured image (because sampling), optical imagery no longer is a continuous quantity.Thereby so long as not the pixel of arranging with radial manner on the electronic image pickup device, the radius of accurately drawing on optical imagery is that the circle of R is accurate circle no longer just.

In other words, about the shape corrections of the view data expressed at each discrete coordinates point, do not exist can be fixedly scaling circle.Therefore, (Xi Yj), can use the method for the coordinate of determining mobile destination (Xi ', Yj ') at each pixel.When (Xi when Yj) moving to coordinate (Xi ', Yj '), adopts the mean value of each pixel with two or more points.And, when not having the point that moves, can utilize the coordinate figure (Xi ', Yj ') of some surrounding pixels to carry out interpolation.

When in the electronic image pickup apparatus that particularly has zoom-lens system with respect to the distortion of optical axis because of the mismachining tolerance of optical system or electronic image pickup device etc. significantly the time, with the radius of on optical imagery, drawing be the circle of R when becoming asymmetric, this method is effective for revising.And when geometric distortion occurring when in image pick-up element or various output unit signal reproduction being become image, this method also is effective for revising.

In electronic image pickup apparatus of the present invention, for computed correction r ' (ω)-r (ω), can construct a kind of structure, make the relation between the r (ω), in other words, relation with between the relation between half image angle and the image height or true image height r and the desirable image height r '/α is recorded in the recording medium that is built in the electronic image pickup apparatus.

Extremely do not lack light quantity in order to make distortion revise image afterwards at the two ends along the shorter side direction, radius R can satisfy the following conditions expression formula.

0≤R≤0.6Ls

Wherein, Ls is the length of the shorter side of effective image pickup surface.

Preferably, radius R satisfies the following conditions expression formula.

0.3Ls≤R≤0.6Ls

And, bestly be, make radius R with in be connected to roughly the effectively radius of the circle of the shorter side direction on image pickup plane coupling.For near radius R=0 ground, in other words unfavorable a little for great amount of images near a situation of the correction of the fixedly scaling multiplying power in ground, even but can guarantee to add the effect that wide angle also makes size decreases.

The focal length of needs correction is divided into a plurality of focal areas at interval.And, near the telescope end in the focal area that marks off, can utilize with correction result and satisfy the same correction under the situation of descending relation of plane substantially, carry out correction:

r′(ω)＝α·f·tanω。

Yet in this case, the wide-angle side in the focal area that marks off has kept barrel-shaped distortion to a certain extent.And, when the quantity of the focal area that increase marks off, need in recording medium, additionally keep revising required particular data.For this reason, preferably, do not increase the quantity of the focal area that marks off.Therefore, calculate the one or more coefficients that are associated with each focal length in the focal area that is marked off in advance.Can determine described coefficient based on simulated measurement or actual equipment measurement.

Correction in the time of can calculating near the telescope end in the focal area that marks off correction result and roughly satisfy relation of plane down:

r ₁′(ω)＝α·f·tanω，

And can be by with the consistent coefficient that multiply by at each focal length of this correction of this correction, and this correction be made as final correction.

In addition, when in by the image that infinite distance object image-forming (formation image) is obtained, not having distortion, keep relation of plane down.

f＝y/tanω

Here, y represents the height (image height) of picture point apart from optical axis, f represents the focal length of imaging system (zoom-lens system among the present invention), and ω represents to be connected to the angle (object half image angle) of the direction of the corresponding object point of the picture point of position y with respect to optical axis with center from the image pickup plane.

When having barrel-shaped distortion in imaging system, above-mentioned relation becomes:

f＞y/tanω

In other words, as the focal distance f that makes imaging system and image height y fixedly the time, it is big that the value of ω becomes.

(digital camera)

Figure 12 is the concept map of above-mentioned zoom-lens system being incorporated into the structure of the digital camera in the image pickup optical system 141 according to of the present invention to Figure 14.Figure 12 is the isometric front view that the outward appearance of digital camera 140 is shown, and Figure 13 is its rear isometric view, and Figure 14 is the schematic section that the structure of digital camera 140 is shown.Figure 12 and Figure 14 show the non-retraction state (lens are pulled out) of image pickup optical system 141.Under the situation of this embodiment, digital camera 140 comprises: have shooting optical path 142 image pickup optical system 141, have finder optical system 143, shutter release button 145, flashlamp 146, LCD monitor 147, the zoom button 161 of view finder (finder) optical path 144 and be provided with and change button 162 etc., and under the retraction state of image pickup optical system 141, by slip cover 160, image pickup optical system 141, finder optical system 143 and flashlamp 146 are covered by lid 160.And, be arranged on the state following time of taking pictures when uncap 160 and with digital camera, image pickup optical system 141 presents non-retraction state shown in Figure 12, and when pushing the shutter release button 145 on the top that is arranged on digital camera 140, with push shutter release button 145 synchronously, take pictures by image pickup optical system 141 such as the zoom-lens system in first embodiment.To be formed on the image pickup surface of CCD 149 via the optical low-pass filter (F) and the cover glass C that are applied with wavelength zone restriction coating by the object picture that image pickup optical system 141 forms.On the LCD monitor on the back side that is arranged on digital camera 140 147, be shown as electronic image via treating apparatus 151 as the object picture that light receives by CCD 149.And, pen recorder 152 is connected to treating apparatus 151, thus the electronic image that can also records photographing arrives.Pen recorder 152 and treating apparatus can be arranged in 151 minutes, perhaps can write to write down and form pen recorder 152 by electronics in floppy disk, storage card or MO etc.And, video camera can be formed replaced C CD 149 wherein and be provided with the silver salt type video camera of silver salt film.

And view finder optical path 144 is provided with view finder objective lens optical system 153.View finder objective lens optical system 153 is made up of a plurality of lens units (being three lens units in the figure) and two prisms, and is made of the varifocal optical system that the zoom-lens system with image pickup optical system 141 synchronously changes focal length.The object that view finder objective lens optical system 153 is formed looks like to be formed on the field frame 157 of the erecting prism (erecting prism) 155 as the erect image parts.On the dorsal part of erecting prism 155, be provided with the eyepiece optical system 159 that erect image is guided to observer's eyes.The side (emergence side) of appearing in one's mind at eyepiece optical system 159 is provided with cover 150.

Because Gou Zao digital camera 140 has according to image pickup optical system 141 of the present invention in such a way, this image pickup optical system 141 has very small thickness under the retraction state, and have extremely stable imaging performance in the whole zoom district under high convergent-divergent multiplying power, so can realize high-performance, miniaturization and wide visual angle.

(internal circuit configuration)

Figure 15 is the structured flowchart of internal circuit of the primary clustering of digital camera 140.In the following description, above-mentioned treating apparatus 151 for example comprises: CDS/ADC portion 124, interim memory 117 and image processing part 118, and memory storage 152 for example comprises storage medium portion 119.

As shown in figure 15, digital camera 140 comprises: operating portion 112, be connected to the control part 113 of operating portion 112, be connected to the interim memory 117 of control signal output ends mouth of control part 113 and imaging drive circuit 116 via bus 114 and bus 115, image processing part 118, storage medium portion 119, display part 120, and configuration information memory portion 121.

Interim memory 117, image processing part 118, storage medium portion 119, display part 120 and configuration information memory portion 121 are configured to via bus 122 mutual input and output data.And CCD 149 and CDS/ADC portion 124 are connected to imaging drive circuit 116.

Operating portion 112 comprises multiple load button and switch, and be to control part notice by the user of digital camera via these load buttons and switch circuit from the event information of outside input.

Control part 113 is CPU (central processing unit) (CPU), and has built-in computer program memory not shown in this Figure.Control part 113 is according to being stored in computer program in this computer program memory, controls the circuit of whole digital camera 140 when receiving by the user of digital camera via the instruction of operating portion 112 inputs and order.

CCD 149 receives the object picture via image pickup optical system 141 formation according to the present invention as light.CCD 149 is that imaging drive circuit 116 drives and the image pick-up element of control, and will convert electric signal at the light quantity of each pixel of object picture, then exports CDS/ADC portion 124 to.

CDS/ADC portion 124 is the circuit that amplify from the electric signal of CCD 149 inputs, and execution analog/digital conversion, then only amplify and convert to the original image data (uncorrected data hereinafter, is called " RAW data ") of numerical data to interim memory 117 outputs.

Interim memory 117 is the impact dampers that for example comprise SDRAM (Synchronous Dynamic Random Access Memory), and is the RAW memory of data device of interim storage from 124 outputs of CDS/ADC portion.Image processing part 118 is to read the RAW data that are stored in the interim memory 117, or be stored in the circuit of the RAW data in the storage medium portion 119, and carry out the multiple Flame Image Process that comprises that distortion is revised in electric mode based on the image quality parameter of appointment in the control part 113.

Storage medium portion 119 is the card that for example comprises flash memory detachably installed or record (storage) medium of bar form.Storage medium portion 119 be will from interim memory 117 transmit the RAW data of coming and image processing part 118, stood the Imagery Data Recording of Flame Image Process and remain on card shape flash memory and bar-shaped flash memory in the control circuit of device.

Display part 120 comprises LCD monitor, and is the circuit of display image and actions menu on LCD monitor.Configuration information memory portion 121 comprises ROM portion that wherein stores various image quality parameters in advance and the RAM portion that stores the image quality parameter of selecting by the input operation on the operating portion 112 from the image quality parameter that ROM portion reads.Configuration information memory 121 is control to the input of these storeies with from the circuit of these storeies outputs.

Gou Zao digital camera 140 has according to image pickup optical system 141 of the present invention in such a way, and it has enough wide-angle district and compact structure, has extremely stable imaging performance in the whole convergent-divergent multiplying power district under high convergent-divergent multiplying power simultaneously.Therefore, can realize high-performance, miniaturization and wide visual angle.And, can realize quick focusing operation at wide-angle side and long coke side end.

As mentioned above, as helping guaranteeing zoom ratio and make the zoom-lens system that size is little and light, and be used for guaranteeing easily optical property according to three-unit zoom lens system of the present invention.

Can provide to be beneficial to and guarantee zoom ratio and make that size is little and light and can easily guarantee the zoom-lens system of optical property and comprise the image pick-up device of this zoom-lens system.

Claims

1, a kind of three-unit zoom lens system, this three-unit zoom lens system comprises in order from object side:

First lens unit with negative refractive power;

Second lens unit with positive refractive power;

The 3rd lens unit with negative refractive power; And

f _t/f _w＞3.8…(1)

d _G3/f _w＜1.0…(2)

Wherein,

d _G3The optical axis thickness of representing the 3rd lens unit.

2, three-unit zoom lens system according to claim 1, wherein, this three-unit zoom lens system satisfies the following conditions expression formula:

3＜D _w/f _w＜8…(3)

0.3＜D _t/f _t＜1.8…(4)

Wherein,

This total optical axis length is passing through will be added into the back focus that the air characteristic chamber length is expressed from the incidence surface of the lens of close object and playing the length that optical axis thickness was obtained of the exit surface of the lens of close image of this three-unit zoom lens system.

3, three-unit zoom lens system according to claim 1, wherein, from wide-angle side during to the telescope end zoom, this second lens unit and the 3rd lens unit satisfy the following conditions expression formula:

0.3＜ΔG ₃/ΔG ₂＜1.2…(5)

Wherein,

Δ G ₂Represent this second lens unit in the position of telescope end with respect to variable quantity in the position of wide-angle side,

Δ G ₃Represent the 3rd lens unit in the position of telescope end with respect to variable quantity in the position of wide-angle side, and

Make the variation of object side become plus sign.

4, three-unit zoom lens system according to claim 1, wherein, this first lens unit comprises the negative lens that the most close described object is provided with, and satisfies the following conditions expression formula:

0.0＜(r _L11+r _L12)/(r _L11-r _L12)＜3.0…(6)

Wherein,

r _L12Represent in this first lens unit the most paraxial radius-of-curvature of the picture side surface of this negative lens of close object.

5, three-unit zoom lens system according to claim 1, wherein, when the lens sum is represented with N in this three-unit zoom lens system, satisfy the following conditions expression formula:

5≤N≤8…(7)。

6, three-unit zoom lens system according to claim 1, wherein,

This second lens unit comprises the cemented lens of being made up of positive lens and negative lens, and

The Abbe number of this negative lens in this second lens unit is less than the Abbe number of this positive lens in this second lens unit.

7, three-unit zoom lens system according to claim 1, wherein, the lens of the 3rd lens unit add up to one.

8, three-unit zoom lens system according to claim 1, wherein, two surfaces of this second lens unit, that is, the lens surface of close object and the lens surface of close image all be non-spherical surface.

9, a kind of image pick-up device, this image pick-up device comprises:

Three-unit zoom lens system; With

Image pick-up element, this image pick-up element are arranged on the picture side of this three-unit zoom lens system, and convert the optical imagery of this three-unit zoom lens system formation to electric signal, wherein,

This three-unit zoom lens system is according to each the described three-unit zoom lens system in the claim 1 to 8.

10, image pick-up device according to claim 9, described image pick-up device comprises:

Image transitions portion, this image transitions portion will comprise that this electrical signal conversion of the distortion that causes because of this three-unit zoom lens system has become by the Flame Image Process correction picture signal of this distortion.

11, image pick-up device according to claim 9, wherein,

Under the state of the wide-angle side of this three-unit zoom lens system, satisfy the following conditions expression formula by optical axis with from the formed angle of chief ray of the maximum image height in the effective image pickup zone that is directed to this image pick-up element of this three-unit zoom lens system outgoing:

-40°＜EX(w)＜-11°…(8)

Wherein,

EX (w) expression is by described optical axis with from the formed angle of chief ray of the maximum image height in the effective image pickup zone that is directed to this image pick-up element of this three-unit zoom lens system outgoing.

12, a kind of three-unit zoom lens system, this three-unit zoom lens system comprises in order from object side:

First lens unit with negative refractive power;

Second lens unit with positive refractive power;

The 3rd lens unit with negative refractive power; And

Aperture diaphragm, this aperture diaphragm be in this first lens unit as side and be in the object side of the lens surface of the most close picture side of this second lens unit, and integrally move with this second lens unit, wherein,

3.8＜f _t/f _w＜5.5…(21)

2.0＜β ₂(t)/β ₂(w)＜3.2…(22)

1.2＜β ₃(t)/β ₃(w)＜1.8…(23)

Wherein,

13, three-unit zoom lens system according to claim 12, wherein, the 3rd lens unit comprises the negative lens element with meniscus shape, and satisfies the following conditions expression formula:

-20＜(r _L31+r _L32)/(r _L31-r _L32)＜-1.0…(24)

Wherein,

14, three-unit zoom lens system according to claim 12, wherein, this three-unit zoom lens system satisfies the following conditions expression formula:

3＜D _w/f _w＜8…(25)

0.3＜D _t/f _t＜1.8…(26)

Wherein,

This total optical axis length be this three-unit zoom lens system pass through will be added into the back focus that the air characteristic chamber length is expressed from the incidence surface of the lens of close object up to the length that optical axis thickness was obtained of the exit surface of the lens of close image.

15, three-unit zoom lens system according to claim 12, wherein, from wide-angle side during to the telescope end zoom, this second lens unit and the 3rd lens unit satisfy the following conditions expression formula:

0.3＜ΔG ₃/ΔG ₂＜1.2…(27)

Wherein,

Δ G ₂The position of telescope end of representing this second lens unit is with respect to the variable quantity of the position of wide-angle side,

Δ G ₃The position of telescope end of representing the 3rd lens unit is with respect to the variable quantity of the position of wide-angle side, and

Make the variation of object side become plus sign.

16, three-unit zoom lens system according to claim 12, wherein, this first lens unit comprises the negative lens that the most close object is provided with, and satisfies the following conditions expression formula:

0.0＜(r _L11+r _L12)/(r _L11-r _L12)＜3.0…(28)

Wherein,

17, three-unit zoom lens system according to claim 12, wherein, when the lens sum is represented with N in this three-unit zoom lens system, satisfy the following conditions expression formula:

5≤N≤8…(29)。

18, three-unit zoom lens system according to claim 12, wherein,

19, three-unit zoom lens system according to claim 12, wherein, the lens of the 3rd lens unit add up to one.

20, three-unit zoom lens system according to claim 12, wherein, two surfaces of this second lens unit, that is, the lens surface of close object and the lens surface of close image all be non-spherical surface.

21, a kind of image pick-up device, this image pick-up device comprises:

Three-unit zoom lens system; With

This three-unit zoom lens system is according to each the described three-unit zoom lens system in the claim 12 to 20.

22, image pick-up device according to claim 21, described image pick-up device comprises:

23, image pick-up device according to claim 21, wherein,

-40°＜EX(w)＜-11°…(10)

Wherein,