CN101458391B

CN101458391B - Zoom lens and electronic imaging apparatus using the same

Info

Publication number: CN101458391B
Application number: CN2008101841085A
Authority: CN
Inventors: 市川启介; 大桥圣仁; 宫田正人
Original assignee: Olympus Imaging Corp
Current assignee: Olympus Corp
Priority date: 2007-12-12
Filing date: 2008-12-11
Publication date: 2012-08-22
Anticipated expiration: 2028-12-11
Also published as: CN101458391A; JP2009163222A; JP5308785B2

Abstract

The invention provides a zoom lens capable of compactifying a size, capable of widening an angle, capable of making variable power high, having satisfactory image quality, and manufactured easily. This zoom lens is provided with the first lens group of negative power, the second lens group of positive power, the third lens group of positive power, and the fourth lens group, in this order from an object side, is constituted to narrow a space between the first lens group and the second lens group and to widen a space between the second lens group and the third lens group, when varying the power of the zoom lens from a wide-angle end to a telescopic end, and has a diaphragm moving integrally with the second lens group between the most image-side lens of the first lens group and the most image-side lens of the second lens group, and the first lens group comprises a negative lens and a positive lens, in this order from the object side, and satisfies the following conditions: 0.15<phi 1MF/phi 1MR<1.0, and -3.0<phi 1PF/phi 1PR<-1.0, wherein phi 1MF represents the power of an object-side face of the negative lens; phi IMR represents the power of an image-side face of the negative lens; phi 1PF represents the power of the object-side face of the positive lens; and phi 1PR represents the power of the image-side face of the positive lens.

Description

Zoom lens and use the electronic image pickup device of this zoom lens

Technical field

The present invention relates to a kind of zoom lens and use the electronic image pickup device of this zoom lens.

Background technology

In recent years; Replace the silver film camera; Digital camera with the such solid-state image pickup of CCD (Charge Coupled Device, charge-coupled image sensor) or CMOS (Complementary Metal-Oxide Semiconductor, CMOS) becomes main flow; In these digital cameras, have various cameras with high functional form to the close-coupled popular style from business.

And wherein for the popular digital camera of close-coupled, customer requirements can easily be enjoyed the enjoyment of photography, except miniaturization, also hope to accomplish slimming so that be received into clothes and the pocket of bag etc. in, easy to carry.

Therefore, require the further miniaturization of zoom lens adopted in the popular digital camera of this close-coupled, require to have following characteristic simultaneously, that is the field angle that, becomes clear, has the hypermutation multiple proportions that surpasses 3 times, diagonal is above 70 °.

And; Following patent documentation 1,2 has been put down in writing a kind of zoom lens that in the popular digital camera of close-coupled, can adopt, and it is made up of the 1st lens combination of negative power (power), the 2nd lens combination of positive light coke, the 3rd lens combination and the 4th lens combination of positive light coke from object side successively.

[patent documentation 1] TOHKEMY 2004-318107 communique

[patent documentation 2] TOHKEMY 2002-365543 communique

But; Though the zoom lens of patent documentation 1,2 records is suitable for miniaturization; But becoming multiple proportions has only about 3 times, the field angle of diagonal is merely about 65 °, doubly changes and wide-angleization if want further to realize hypermutation, then will cause radially and along the size of the direction of optical axis the increasing of the 1st lens combination of negative power; As a result, there is the problem that causes the whole change of optical system to be maximized.

And; The zoom lens of patent documentation 1,2 record is in order to realize hypermutation doubly change and miniaturization and when strengthening each power of lens; Cause constituting in the lens of the 1st lens combination near the lens of the negative power of object side and reducing in radius-of-curvature as the face of side; Poor (variation in thickness is poor) of center thickness and edge (コバ) thickness increases, so the processing of lens change difficulty, and because the deviation in the assembling of the lens of formation the 1st lens combination; Cause a upward coma increase of high order, have the problem that is difficult to guarantee the good productivity and the optical property of abundance.

Summary of the invention

The present invention proposes in view of such prior art problems; Its purpose is; Provide a kind of and help miniaturization, wide-angleization, hypermutation and doubly change, the image quality of photographs is good, and the zoom lens of making easily and use the electronic image pickup device of this zoom lens.

In order to achieve the above object; Zoom lens of the present invention is characterised in that; Have the 1st lens combination of negative power, the 2nd lens combination of positive light coke, the 3rd lens combination and the 4th lens combination of positive light coke successively from object side; From wide-angle side when telescope end becomes times, the interval of said the 1st lens combination and said the 2nd lens combination diminishes, the interval of said the 2nd lens combination and said the 3rd lens combination becomes big simultaneously; Said the 1st lens combination near the lens of picture side and said the 2nd lens combination near looking like between the lens of side; Have the brightness diaphragm that moves integratedly with said the 2nd lens combination, said the 1st lens combination is made up of the 1st lens of the negative power that is disposed at object side and the 2nd lens that are disposed at as the positive light coke of side, and the formula that meets the following conditions (1), (2).

0.15＜φ _1MF/φ _1MR＜1.0......(1)

-3.0＜φ _1PF/φ _1PR＜-1.0......(2)

Wherein, φ _1MFThe focal power of face of object side of the 1st lens that refers to the negative power of said the 1st lens combination, φ _1MRThe focal power of face of picture side of the 1st lens that refers to the negative power of said the 1st lens combination, φ _1PFThe focal power of face of object side of the 2nd lens that refers to the positive light coke of said the 1st lens combination, φ _1PRThe focal power of face of picture side of the 2nd lens that refers to the positive light coke of said the 1st lens combination.

In addition, zoom lens of the present invention constitutes when the formula of satisfying condition (1), (2), and the two sides of the 1st lens of the negative power of preferred said the 1st lens combination is an aspheric surface.

And; In order to achieve the above object; Zoom lens of the present invention is characterised in that; Have the 1st lens combination of negative power, the 2nd lens combination of positive light coke, the 3rd lens combination and the 4th lens combination of positive light coke successively from object side; From wide-angle side when telescope end becomes times, the interval of said the 1st lens combination and said the 2nd lens combination diminishes, the interval of said the 2nd lens combination and said the 3rd lens combination becomes big simultaneously; Said the 1st lens combination near the lens of picture side and said the 2nd lens combination near looking like between the lens of side; Have the brightness diaphragm that moves integratedly with said the 2nd lens combination, said the 1st lens combination is made up of the 1st lens of the negative power that is disposed at object side and the 2nd lens that are disposed at as the positive light coke of side, and said the 3rd lens combination and said the 4th lens combination only are made up of the meniscus lens of concave surface towards object side respectively.

In addition, zoom lens of the present invention said the 3rd lens combination and said the 4th lens combination respectively only by concave surface when a meniscus lens of object side constitutes, the formula that preferably meets the following conditions (3).

15＜(φ3/φ4)＜320......(3)

Wherein, φ ₃The focal power that refers to said the 3rd lens combination, φ ₄The focal power that refers to said the 4th lens combination.

And zoom lens of the present invention only utilizes concave surface respectively when a meniscus lens of object side constitutes in said the 3rd lens combination and said the 4th lens combination, the formula that preferably meets the following conditions (4).

-10＜(R _3r+R _4f)/(R _3r-R _4f)＜0......(4)

Wherein, R _3rThe paraxial radius-of-curvature of the face of the picture side of the meniscus lens of said the 3rd lens combination of finger formation, R _4fThe paraxial radius-of-curvature of the face of the object side of the meniscus lens of said the 4th lens combination of finger formation.

And, zoom lens of the present invention said the 3rd lens combination and said the 4th lens combination respectively only by concave surface when a meniscus lens of object side constitutes, the formula that preferably meets the following conditions (5).

1＜ds/dt＜1.5......(5)

Wherein, Ds refers to the interval of the point that the face of point that the face of and line through maximum image height position shooting face on parallel with optical axis in wide-angle side and the picture side of the meniscus lens that constitutes said the 3rd lens combination intersects and this line and the object side of the meniscus lens that constitutes said the 4th lens combination intersects, and dt refers to constitute in wide-angle side the interval of face on optical axis of object side of meniscus lens of face and said the 4th lens combination of formation of picture side of the meniscus lens of the 3rd lens combination.

And, the zoom lens of the present invention formula (6) that preferably meets the following conditions.

6≤N≤9......(6)

Wherein, N refers to the lens total quantity of said zoom lens.

And preferred said the 2nd lens combination of zoom lens of the present invention is made up of the lens below 3.

And preferred said the 2nd lens combination of zoom lens of the present invention is by the lens of positive light coke and the lens of the lens of positive light coke and negative power are engaged the joint lens that obtain constitute.

And; Preferred said the 2nd lens combination of zoom lens of the present invention has the joint lens that the lens joint with the lens of positive light coke and negative power obtains, and the Abbe number of the lens of the negative power of said joint lens is less than the Abbe number of the lens of the positive light coke of said joint lens.

And, zoom lens of the present invention in said the 2nd lens combination by the lens of positive light coke, when joint lens that the lens of lens that engage positive light coke and negative power obtain constitute, the formula that preferably meets the following conditions (7), (8).

n _2pave≥1.59......(7)

υ _2n≤35......(8)

Wherein, n _2paveThe mean value of the refractive index of the lens of the whole positive light cokes that refer to comprise in said the 2nd lens combination, υ _2nThe Abbe number of the lens of the negative power that refers to comprise in said the 2nd lens combination.

And; Zoom lens of the present invention engages the joint lens that obtain when constituting in said the 2nd lens combination by the lens of positive light coke and with the lens of the lens of positive light coke and negative power, preferably constitutes interval between the lens of said the 2nd lens combination less than the center thickness of the lens of the negative power that comprises in said the 2nd lens combination.

And, zoom lens of the present invention preferably meet the following conditions formula (9), (10).

n _3ave≥1.48......(9)

υ _3ave≥60......(10)

Wherein, n _3aveThe mean value of the refractive index of whole lens of finger formation the 3rd lens combination, υ _3aveThe mean value of the Abbe number of whole lens of finger formation the 3rd lens combination.

And preferred said the 3rd lens combination of zoom lens of the present invention is made up of the aspheric lens with at least more than one.

And preferred said the 3rd lens combination of zoom lens of the present invention is made up of at least one resin lens.

And preferred said the 4th lens combination of zoom lens of the present invention is made up of lens, and the formula that meets the following conditions (11), (12).

n ₄≥1.48......(11)

υ ₄≥60......(12)

Wherein, n ₄The refractive index that refers to lens of said the 4th lens combination of formation, υ ₄The Abbe number that refers to lens of said the 4th lens combination of formation.

And preferred said the 4th lens combination of zoom lens of the present invention is made up of the aspheric lens with at least more than one.

And preferred said the 4th lens combination of zoom lens of the present invention is made up of resinous lens.

And preferred said the 4th lens combination of zoom lens of the present invention does not move when becoming times.

And; Electronic image pickup device of the present invention has zoom lens, is configured near electro-photographic element, graphics processing unit and the record cell of image space of said zoom lens; Said graphics processing unit is processed the view data that is obtained by said electro-photographic element, makes its alteration of form, and is recorded in the said record cell; Said electronic image pickup device is characterised in that; Said zoom lens is the zoom lens of above-mentioned arbitrary invention record, when roughly infintie object point is focused, and the formula that meets the following conditions (13).

0.7＜y ₀₇/(f _w·tanω _07w)＜1.5......(13)

Wherein, (in the face that can make a video recording) distance (maximum image height) from the center to the solstics is made as y in effective shooting face of electro-photographic element ₁₀The time, utilize y ₀₇=0.7y ₁₀Expression, ω _07wFinger and the center from the shooting face of wide-angle side are connected to y ₀₇The object point direction of the picture point correspondence of position is with respect to the angle of optical axis.

According to the present invention, can provide a kind of and help miniaturization, wide-angleization, hypermutation and doubly change, the image quality of photographs is good, and the zoom lens of making easily and use the electronic image pickup device of this zoom lens.

Description of drawings

Fig. 1 be the optical texture of zoom lens when infintie object point focus that relate to of expression embodiments of the invention 1, along the sectional view of optical axis, represent the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 2 is the figure of the spherical aberration of expression zoom lens shown in Figure 1 when infintie object point focus, astigmatism, distortion aberration, ratio chromatism,, representes the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 3 be the optical texture of zoom lens when infintie object point focus that relate to of expression embodiments of the invention 2, along the sectional view of optical axis, represent the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 4 is the figure of the spherical aberration of expression zoom lens shown in Figure 3 when infintie object point focus, astigmatism, distortion aberration, ratio chromatism,, representes the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 5 be the optical texture of zoom lens when infintie object point focus that relate to of expression embodiments of the invention 3, along the sectional view of optical axis, represent the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 6 is the figure of the spherical aberration of expression zoom lens shown in Figure 5 when infintie object point focus, astigmatism, distortion aberration, ratio chromatism,, representes the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 7 be the optical texture of zoom lens when infintie object point focus that relate to of expression embodiments of the invention 4, along the sectional view of optical axis, represent the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 8 is the figure of the spherical aberration of expression zoom lens shown in Figure 7 when infintie object point focus, astigmatism, distortion aberration, ratio chromatism,, representes the state of (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

Fig. 9 is the stereographic map when the front is watched of the outward appearance of the expression digital camera that assembled zoom lens of the present invention.

Front view when Figure 10 is watching from behind of expression digital camera shown in Figure 9.

Figure 11 is the perspective plan view that schematically illustrates the structure of digital camera shown in Figure 9.

Label declaration

G ₁The 1st lens combination; G ₂The 2nd lens combination; G ₃The 3rd lens combination; G ₄The 4th lens combination; L ₁₁, L ₁₂, L ₂₁, L ₂₂, L ₂₃, L ₃, L ₄Lens; The Lc optical axis; S brightness diaphragm; The LF low-pass filter; C G cloche; The IM face of making a video recording; E observer's eyeball; 10 digital cameras; 11 photographic optical systems; Light path is used in 12 photographies; 13 finder optical systems; 14 view finders are used light path; 15 shutter release buttons; 16 flashlamp illuminating parts; 17 LCD monitors; 18CCD; 19 cap assemblies; 20 processing units; 21 record cells; 22 view finders are used objective lens optical system; 23 erecting prisms; 24 visual field frames; 25 eyepiece optical systems; 26 covers; 27 focal lengths change button; 28 set alternation switch.

Embodiment

Before the embodiment of explanation zoom lens of the present invention and the electronic image pickup device that uses this zoom lens, explain based on the action effect of zoom lens of the present invention with the structure of the electronic image pickup device that uses this zoom lens.

As basic structure; Zoom lens of the present invention constitutes; Have the 1st lens combination of negative power, the 2nd lens combination of positive light coke, the 3rd lens combination and the 4th lens combination of positive light coke successively from object side; From wide-angle side when telescope end becomes times, the interval of the 1st lens combination and the 2nd lens combination diminishes, the interval of the 2nd lens combination and the 3rd lens combination becomes big simultaneously.

In the zoom lens of the present invention that adopts this structure; The 1st lens combination has negative focal power, so can realize wide-angleization and miniaturization radially, can reduce the quantity of the lens combination that will constitute simultaneously; And can reduce the quantity of lens combination; Therefore also can reduce necessary lens number, the result can realize the slimming of picture frame and the reduction of cost.And the 2nd lens combination has positive focal power so that through changing the effect of bringing into play change crowd (variator) with the distance of the 1st lens combination, simultaneously from wide-angle side when telescope end becomes times, can increase doubly from moving as the side direction object side.And the 3rd lens combination has positive focal power, so the performance when guaranteeing to shorten total lens length easily realizes miniaturization.And; Mainly utilized the 1st lens combination to proofread and correct at aberrations such as the 2nd group of astigmatism that produces and curvature of the images in the past; But since can be in the end one group promptly the 4th lens combination proofread and correct; So need be at the 1st lens combination aberration such as correcting astigmatism and curvature of the image exceedingly, can fully proofread and correct and follow hypermutation doubly to change and the spherical aberration and the coma that increase.

And as basic structure, zoom lens of the present invention constitutes, the 1st lens combination near the lens of picture side and the 2nd lens combination near the picture lens of side between, have the brightness diaphragm mobile integratedly with said the 2nd lens combination.

In the zoom lens of the present invention that adopts this structure, can keep compactedness, and guarantee the performance of wide-angle side easily.And brightness diaphragm and the 2nd lens combination move integratedly, can simplify driving mechanism thus.In addition; Do not move integratedly at the brightness diaphragm with the 2nd lens combination; Compare this structure and when wide-angle side, more be positioned under the situation of object side, the light height of the peripheral light beam in the 2nd lens combination uprises, so each lens that cause constituting the 2nd lens combination are radially maximizing.In addition; The major part of the imaging effect that the 2nd lens combination burden lens combination is whole; So the lens that require to constitute the 2nd lens combination also have more intense focal power; But in the brightness location of aperture is under the situation of the sort of position, must increase lens numbers in order to ensure focal power, causes being difficult to obtain the slimming of picture frame and the balance of spherical aberration and coma.And, the brightness diaphragm being compared with the 2nd lens combination more be positioned under the picture situation of side constituting, the light height of the axle outer light beam of wide-angle side uprises, so must increase the 1st lens combination, causes being difficult to realize wide-angleization and miniaturization.

And zoom lens of the present invention is on the basis of basic structure, and the 1st lens combination is made up of the 1st lens of the negative power that is disposed at object side and the 2nd lens that are disposed at as the positive light coke of side, and the formula that meets the following conditions (1), (2),

0.15＜φ _1MF/φ _1MR＜1.0......(1)

-3.0＜φ _1PF/φ _1PR＜-1.0......(2)

Wherein, φ _1MFThe focal power of face of object side of the 1st lens that refers to the negative power of the 1st lens combination, φ _1MRThe focal power of face of picture side of the 1st lens that refers to the negative power of the 1st lens combination, φ _1PFThe focal power of face of object side of the 2nd lens that refers to the positive light coke of the 1st lens combination, φ _1PRThe focal power of face of picture side of the 2nd lens that refers to the positive light coke of the 1st lens combination.

When the 2nd lens of the 1st lens that utilize negative power and positive light coke constitute the 1st lens combination; More than half part of the negative power through making the 1st lens concentrated on the face of its object side in the past; More than half part of the positive light coke of the 2nd lens is concentrated on its face as side, come aberrations such as correcting spherical aberration and curvature of the image thus.But, if focal power is concentrated, then cause producing the spherical aberration of high order, doubly change so be difficult to realize hypermutation.And the deviation during owing to assembling causes the influence of the aberration of high order to increase, and is difficult to guarantee sufficient optical property.In addition, because the 1st power of lens distributes imbalance, so lens become the bigger shape that thickness does not wait, in order to realize wide-angleization, must form the darker lens shape of segment, cause the processing difficulties of lens, design is restricted.

Therefore, zoom lens of the present invention constitutes conditional (1), (2) of the optimal light focal power distribution of each lens that satisfy expression formation the 1st lens combination.Zoom lens of the present invention satisfies this conditional (1), (2), so even will become multiple proportions brings up to about 4 times, also can guarantee sufficient optical property, and can guarantee good production performance.

If be lower than the lower limit of conditional (1), the spherical aberration of the high order that then in the 1st lens of the 1st lens combination, produces increases, and is difficult to carry out the correction of the spherical aberration in whole lens area.And the shape of the 1st lens of the 1st lens combination becomes the bigger shape that thickness does not wait, and design receives the restriction of lens processing characteristics.On the other hand,, then be difficult to carry out the spherical aberration of change when becoming times, the correction of curvature of the image, can not guarantee the optical property of the abundance of whole lens area equally if surpass the upper limit of conditional (1).

In addition, preferably constitute the following conditional (1) that satisfy to replace conditional (1) ', (1) " in any conditional.

0.2＜φ _1MF/φ _1MR＜0.8......(1)’

0.35＜φ _1MF/φ _1MR＜0.7......(1)”

And, also can be conditional (1) ' higher limit or lower limit as conditional (1), (1) " higher limit or lower limit, can also be conditional (1) " higher limit or lower limit as conditional (1), (1) ' higher limit or lower limit.

If be lower than the lower limit of conditional (2), the air power of lens that then between the 1st lens of the 1st lens combination and the 2nd lens, forms diminishes, and can not fully proofread and correct the curvature of the image of too small (under) that follow the wide-angle generation.On the other hand, if surpass the upper limit of conditional (2), the air power of lens that then between the 1st lens of the 1st lens combination and the 2nd lens, forms becomes big, and the curvature of the image of wide-angle side becomes excessive, can not guarantee sufficient optical property.And, follow wide-angleization, the interval of the 1st lens of the 1st lens combination and the edge of the 2nd lens dwindles, so the interval of these lens increases, the thickness along the direction of optical axis of the 1st lens combination increases.

In addition, preferably constitute the following conditional (2) that satisfy to replace conditional (2) ', (2) " in arbitrary conditional.

-2.5＜φ _1PF/φ _1PR＜-1.7......(2)’

-2.0＜φ _1PF/φ _1PR＜-1.8......(2)”

And, also can be conditional (2) ' higher limit or lower limit as conditional (2), (2) " higher limit or lower limit, can also be conditional (2) " higher limit or lower limit as conditional (2), (2) ' higher limit or lower limit.

In addition, zoom lens of the present invention is on the basis of basic structure, and when constituting the formula of satisfying condition (1), (2), the two sides of the 1st lens of the negative power of preferred the 1st lens combination is an aspheric surface.

The two sides of the 1st lens through making the 1st lens combination forms aspheric surface, can suppress the generation of spherical aberration, curvature of the image, distortion aberration.

In addition, zoom lens of the present invention only is made up of said the 3rd lens combination and said the 4th lens combination respectively on the basis of basic structure the meniscus lens of concave surface towards object side.

In the zoom lens of the present invention that adopts this structure, utilize the 2nd lens combination to proofread and correct the curvature of the image of the negative direction that results from whole zoom area, reduce the burden of the curvature of the image correction of the 1st lens combination, realize suitable power configuration easily.As a result, proofread and correct easily and follow wide-angleization and hypermutation doubly to change and the aberration that produces.And; From wide-angle side when telescope end becomes times; The axle outer light beam increases towards the incident angle of the face of the object side of the 3rd lens combination and the 4th lens combination, thus the optical path difference of wide-angle side and telescope end increase, can suppress peripheral part because of becoming the doubly change of the curvature of the image of the high order of formation.

In addition, zoom lens of the present invention on the basis of basic structure, said the 3rd lens combination and said the 4th lens combination respectively only by concave surface when a meniscus lens of object side constitutes, the formula that preferably meets the following conditions (3),

15＜(φ3/φ4)＜320......(3)

Conditional (3) is the conditional of the corrective action of regulation curvature of the image rightly.If be lower than the lower limit of conditional (3), then curvature of the image, astigmatism are excessive.And if surpass the upper limit, the effect of then proofreading and correct curvature of the image weakens, and the burden of the 1st lens combination increases, and can not realize suitable power configuration, is difficult to realize that hypermutation doubly changes.

In addition, zoom lens of the present invention on the basis of basic structure, said the 3rd lens combination and said the 4th lens combination respectively only by concave surface when a meniscus lens of object side constitutes, the formula that preferably meets the following conditions (4),

-10＜(R _3r+R _4f)/(R _3r-R _4f)＜0......(4)

Conditional (4) is the conditional of the shape of regulation lens rightly.If make the 3rd lens combination near forming in the bound of conditional (4) near the paraxial radius-of-curvature of the face of object side as the paraxial radius-of-curvature of the face of side and said the 4th lens combination; Then can utilize the space efficiently, can make zoom lens form compact structure.

In addition, zoom lens of the present invention on the basis of basic structure, said the 3rd lens combination and said the 4th lens combination respectively only by concave surface when a meniscus lens of object side constitutes, the formula that preferably meets the following conditions (5),

1＜ds/dt＜1.5......(5)

Conditional (5) is the conditional of the shape of regulation lens rightly.If the interval of the 3rd lens combination and the 4th lens combination is formed in the bound of conditional (5), then can utilize the space efficiently, can make zoom lens form compact structure.

In addition, the zoom lens of the present invention formula (6) that preferably meets the following conditions,

6≤N≤9......(6)

Wherein, N refers to the lens total quantity of zoom lens.

If the lower limit of the conditional of being not less than (6) then can make the focal power of each lens combination that is disposed at zoom lens obtain good balance, suppress the generation of aberration easily.And, if the upper limit of the conditional of being no more than (6) then can reduce the formation quantity of lens.

In addition, preferred the 2nd lens combination of zoom lens of the present invention is made up of the lens below 3.

Through utilizing 3 lens to constitute the 2nd lens combination, can make optical system integral body form compact structure.

In addition, preferred the 2nd lens combination of zoom lens of the present invention is by the lens of positive light coke; And the lens of the lens of positive light coke and negative power are engaged the joint lens that obtain constitute.

Lens through utilizing positive light coke and the lens of the lens of positive light coke and negative power are engaged the joint lens that obtain constitute the 2nd lens combination, the structure of the aberration in the time of can forming easy correction high magnificationization with wide-angle.

In addition, zoom lens of the present invention is at the lens of the 2nd lens combination by positive light coke; And the lens of the lens of positive light coke and negative power are engaged the joint lens that obtain when constituting; Preferred the 2nd lens combination has the joint lens that the lens with the lens of positive light coke and negative power must join to, and the Abbe number of lens of negative power that engages lens is less than the Abbe number of the lens of the positive light coke of said joint lens.

Engage the joint lens that obtain when constituting the 2nd lens combination at the lens that utilize positive light coke and with the lens of the lens of positive light coke and negative power; The Abbe number of the lens through making negative power can form the structure of easy correcting chromatic aberration and curvature of the image less than the Abbe number of the lens of positive light coke.

In addition, zoom lens of the present invention engages the joint lens that obtain when constituting in the 2nd lens combination by the lens of positive light coke and with the lens of the lens of positive light coke and negative power, the formula that preferably meets the following conditions (7), (8),

n _2pave≥1.59......(7)

υ _2n≤35......(8)

If the lower limit of the conditional of being not less than (7), then easy correcting astigmatism.And, if the upper limit of the conditional of being no more than (8), then easy correcting chromatic aberration.

In addition, zoom lens of the present invention preferably constitutes interval between the lens of the 2nd lens combination less than the center thickness of the lens of the negative power that comprises in the 2nd lens combination.

If form this structure, then realize miniaturization easily.

In addition, zoom lens of the present invention preferably meet the following conditions formula (9), (10),

n _3ave≥1.48......(9)

υ _3ave≥60......(10)

Under the situation of the zoom lens of having accomplished miniaturization according to the present invention, when utmost point close-shot shadow, in the 3rd lens combination, be difficult for correcting astigmatism.Therefore, preferred the 3rd lens combination forms the low dispersion of high index of refraction as much as possible.Therefore, if be lower than the lower limit of conditional (9), (10), then be difficult to correcting astigmatism, aberration.

In addition, preferably constitute the following conditional (9) that satisfy to replace conditional (9) ', (9) " in arbitrary conditional, and satisfy the following conditional (10) that replaces conditional (10) ', (10) " in arbitrary conditional.

n _3ave≥1.50......(9)’

n _3ave≥1.52......(9)”

υ _3ave≥58......(10)’

υ _3ave≥55......(10)”

In addition, preferred the 3rd lens combination of zoom lens of the present invention is made up of the aspheric lens with at least more than one.

Under the situation of the zoom lens of having accomplished miniaturization according to the present invention, when utmost point close-shot shadow, in the 3rd lens combination, be difficult for correcting astigmatism.Therefore, preferably utilizing single face or two sides is that the lens of aspheric surface constitute the 3rd lens combination.In addition, preferably these lens are to have the lens of the curvature of the face that looks like side greater than the shape of the curvature of the face of object side.

In addition, preferred the 3rd lens combination of zoom lens of the present invention is made up of at least one resin lens.

If utilize at least one resin lens to constitute the 3rd lens combination, then can suppress cost, also carry out the lens moulding easily.

In addition, preferred the 4th lens combination of zoom lens of the present invention is made up of lens, and the formula that meets the following conditions (11), (12),

n ₄≥1.48......(11)

υ ₄≥60......(12)

Wherein, n ₄The refractive index that refers to lens of formation the 4th lens combination, υ ₄The Abbe number that refers to lens of formation the 4th lens combination.

Under the situation of the zoom lens of having accomplished miniaturization according to the present invention, when utmost point close-shot shadow, in the 4th lens combination, be difficult for correcting astigmatism.Therefore, preferred the 4th lens combination forms the low dispersion of high index of refraction as much as possible.Therefore, if be lower than the lower limit of conditional (11), (12), then be difficult to correcting astigmatism, aberration.

In addition, preferably constitute the following conditional (11) that satisfy to replace conditional (11) ', (11) " in arbitrary conditional, and satisfy the following conditional (12) that replaces conditional (12) ', (12) " in arbitrary conditional.

n ₄≥1.50......(11)’

n ₄≥1.52......(11)”

υ ₄≥58......(12)’

υ ₄≥55......(12)”

In addition, preferred the 4th lens combination of zoom lens of the present invention is made up of the aspheric lens with at least more than one.

Under the situation of the zoom lens of having accomplished miniaturization according to the present invention, when utmost point close-shot shadow, in the 4th lens combination, be difficult for correcting astigmatism.Therefore, preferred the 4th lens combination is made up of the aspheric lens with at least more than one.In addition, preferably these lens are to have the lens of the curvature of the face that looks like side greater than the shape of the curvature of the face of object side.

In addition, preferred the 4th lens combination of zoom lens of the present invention is made up of resinous lens.

If utilize at least one resin lens to constitute the 4th lens combination, then can suppress cost, also carry out the lens moulding easily.

In addition, preferred the 4th lens combination of zoom lens of the present invention does not move when becoming times.

Through the 4th lens combination is not moved when becoming times, can simplify drive division mechanism, realize miniaturization easily.

In addition, electronic image pickup device of the present invention has zoom lens, is configured near electro-photographic element, graphics processing unit and the record cell of image space of said zoom lens, the view data that said graphics processing unit processing is obtained by said electro-photographic element; Make its alteration of form; And be recorded in the said record cell, zoom lens is above-mentioned any zoom lens, when infintie object point focusing roughly; The formula that meets the following conditions (13)

0.7＜y ₀₇/(f _w·tanω _07w)＜1.5......(13)

Under the situation of the zoom lens of having accomplished miniaturization according to the present invention, when as the present invention, having realized miniaturization, astigmatic correction and barrel aberrance emendation form the relation that (trade off) selected in compromise easily.Therefore, if allow to produce distortion aberration to a certain degree, then can utilize the distortion of the image processing function correcting image shape that electronic image pickup device has.Therefore, this bearing calibration is described.

For example, utilize the optical system imaging infinity object of the aberration that do not distort.During this situation, not distortion in the picture of imaging is so following conditional (14) is set up.

f＝y/tanω......(14)

Wherein, y refers to the height of picture point apart from optical axis, and f refers to the focal length of imaging system, and ω refers to be connected to the angle of the corresponding object point direction of the picture point of y position with respect to optical axis with center from shooting face.

On the other hand, when having only optical system to be near the state the wide-angle side, just allow under the situation of barrel distortion aberration, following conditional (15) is set up.

f＞y/tanω......(15)

That is, if be made as certain value to ω and y, then the focal distance f of wide-angle side also can be long, correspondingly easy aberration correction.And; The lens combination that is equivalent to the 1st lens combination of zoom lens of the present invention utilizes plural composition to constitute usually; Its reason is can carry out the correction of astigmatism again for the correction of the aberration that can distort; If but allowed distortion aberration to a certain degree, then need not carry out above-mentioned two kinds of corrections, with easy correcting astigmatism.

Therefore; In electronic image pickup device of the present invention; The signal processing system of utilizing electronic image pickup device is that graphics processing unit is processed the electronics that the view data enforcement that is obtained by the electro-photographic element is equivalent to the change in shape of picture, so that proofread and correct barrel-shaped distortion aberration.

The view data that like this, finally obtains becomes and has and the object view data of similar shape roughly.Therefore, can be according to the image of this view data to CRT or printer output object.

And conditional (13) has been stipulated the degree of the barrel distortion of wide-angle side.If the formula of satisfying condition (13), then correcting astigmatism reasonably can realize the slimming of optical system.In addition, distortion becomes barrel-shaped picture and carries out opto-electronic conversion through imaging apparatus, forms distortion and becomes barrel-shaped view data.But distortion becomes barrel-shaped view data is implemented to be equivalent to the change in shape of picture through graphics processing unit processing.Like this, even reproduce final view data, also can obtain to distort be corrected with taken the photograph the roughly similar image of shape.

When surpassing the higher limit of conditional (13), especially when getting near 1 value, the aberration that is equivalent to distort is by optical correction well, but is difficult for correcting astigmatism.On the other hand, when being lower than the lower limit of conditional (13), when utilizing graphics processing unit to proofread and correct the anamorphose based on the distortion aberration of optical system, too high towards the magnification of the radiation direction of field angle periphery.As a result, the deterioration apparition of the bright acutance of image periphery.

In addition, preferably constitute the following conditional (13) that satisfy to replace conditional (13) ', (13) " in arbitrary conditional.

0.75＜y ₀₇/(f _w·tanω _07w)＜1.3......(13)’

0.80＜y ₀₇/(f _w·tanω _07w)＜1.1......(13)”

And, also can be conditional (13) ' higher limit or lower limit as conditional (13), (13) " higher limit or lower limit, can also be conditional (13) " higher limit or lower limit as conditional (13), (13) ' higher limit or lower limit.

Below, with reference to description of drawings embodiments of the invention 1～4.

In the accompanying drawings, the r in the optical system sectional view ₁, r ₂... and d ₁, d ₂... in be represented as subscript type numeral corresponding to the face sequence number in the numeric data 1,2 ....And in aberration curve figure, the Δ M in the astigmatism representes the astigmatism of meridian ellipse, and Δ S representes the astigmatism of sagittal surface.In addition, said meridian ellipse refers to comprise the optical axis of optical system and the face of chief ray (face parallel with paper), and said sagittal surface refers to the face vertical with the face of optical axis that comprises optical system and chief ray (face vertical with paper).

And in the numeric data of the lens of following each embodiment, R representes the radius-of-curvature of each face, the D presentation surface at interval, Nd representes the refractive index at d line place, υ d representes the Abbe number at d line place, K representes circular cone coefficient, A ₄, A ₆, A ₈, A ₁₀The expression asphericity coefficient.

And each asphericity coefficient that each aspherical shape is used each embodiment utilizes following formula to represent.Wherein, be made as Z to coordinate, be made as Y to the coordinate of the direction vertical with optical axis along the direction of optical axis.

Z＝(Y ²/r)/[1+{1-(1+K)·(Y/r) ²} ^1/2]

+A ₄Y ⁴+A ₆Y ⁶+A ₈Y ⁸+A ₁₀Y ¹⁰+…

[embodiment 1]

Optical texture when Fig. 1 is the infintie object point focusing of the zoom lens that relates to of expression present embodiment, along the sectional view of optical axis, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.Fig. 2 is spherical aberration, astigmatism, the distortion aberration in infintie object point when focusing of expression zoom lens shown in Figure 1, the figure of ratio chromatism,, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

At first, use Fig. 1 that the optical texture of the zoom lens of present embodiment is described.The zoom lens of present embodiment disposes the 1st lens combination G of negative power successively from object side on optical axis L c ₁, positive light coke the 2nd lens combination G ₂, positive light coke the 3rd lens combination G ₃With the 4th lens combination G ₄And, at the 1st lens combination G ₁With the 2nd lens combination G ₂Between dispose brightness diaphragm S.In addition, at the 4th lens combination G ₄The picture side, dispose low-pass filter LF, CCD cloche CG successively, have the CCD of shooting face IM from object side.

The 1st lens combination G ₁From object side is that aspheric biconcave lens is the 1st lens L of negative power by the two sides successively ₁₁, and convex surface be the 2nd lens L of positive light coke towards the meniscus lens of object side ₁₂Constitute.

The 2nd lens combination G ₂From object side is that aspheric biconvex lens is the lens L of positive light coke by the two sides successively ₂₁, and convex surface be the lens L of positive light coke towards the meniscus lens of object side ₂₂With convex surface be the lens L of negative power towards the meniscus lens of object side ₂₃The joint lens constitute.

The 3rd lens combination G ₃Only be the lens L of positive light coke by meniscus lens ₃Constitute, it utilizes ester moulding, is aspheric surface as the face of side, and convex surface is towards the picture side.

The 4th lens combination G ₄Only be the lens L of negative power by meniscus lens ₄Constitute, its face as side is an aspheric surface, and convex surface is towards the picture side.

And, from wide-angle side when telescope end becomes times, the 1st lens combination G ₁At first move to the picture side, move to object side then, so to-and-fro movement on optical axis L c.The 2nd lens combination G ₂With brightness diaphragm S, on optical axis L c, move to object side, reduce simultaneously and the 1st lens combination G ₁The interval.The 3rd lens combination G ₃Enlarging and the 2nd lens combination G ₂The interval time, at first move to the picture side, move to object side then, so to-and-fro movement on optical axis L c.In addition, the 4th lens combination G of this moment ₄Do not move.

Below, the structure and the numeric data of the lens of each optical system that expression formation present embodiment relates to.In addition, unit is mm.

The face data

Aspherical surface data

Various data

The zoom lens group data

Data based on above-mentioned conditional

Conditional (1) 0.15＜φ _1MF/ φ _1MR＜1.0:0.473

Conditional (2)-3.0＜φ _1PF/ φ _1PR＜-1.0:-1.859

Conditional (3) 15＜(φ 3/ φ 4)＜320:31.172608

Conditional (4)-10＜(R _3r+ R _4f)/(R _3r-R _4f)＜0:-4.057395

Conditional (5) 1＜ds/dt＜1.5:1.1435555

Conditional (6) 6≤N≤9:7

Conditional (7) n _2pave>=1.59:1.685

Conditional (8) v _2n≤35:53.385

Conditional (9) n _3ave>=1.48:1.531

Conditional (10) v _3ave>=60:55.8

Conditional (11) n ₄>=1.48:1.531

Conditional (12) v ₄>=60:55.8

Conditional (13) 0.7＜y ₀₇/ (f _wTan ω _07w)＜1.5:0.920

[embodiment 2]

Optical texture when Fig. 3 is the infintie object point focusing of the zoom lens that relates to of expression present embodiment, along the sectional view of optical axis, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.Fig. 4 is spherical aberration, astigmatism, the distortion aberration in infintie object point when focusing of expression zoom lens shown in Figure 3, the figure of ratio chromatism,, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

At first, use Fig. 3 that the optical texture of the zoom lens of present embodiment is described.The zoom lens of present embodiment disposes the 1st lens combination G of negative power successively from object side on optical axis L c ₁, positive light coke the 2nd lens combination G ₂, positive light coke the 3rd lens combination G ₃With the 4th lens combination G ₄And, at the 1st lens combination G ₁With the 2nd lens combination G ₂Between dispose brightness diaphragm S.In addition, at the 4th lens combination G ₄The picture side, dispose the flat low-pass filter LF in plane, plane flat CCD cloche CG successively, have the CCD of shooting face IM from object side.

The 2nd lens combination G ₂Be made up of following successively from object side: the two sides is that aspheric biconvex lens is the lens L of positive light coke ₂₁And convex surface is the lens L of positive light coke towards the meniscus lens of object side ₂₂With convex surface be the lens L of negative power towards the meniscus lens of object side ₂₃The joint lens.

The face data

Aspherical surface data

Various data

The zoom lens group data

Data based on above-mentioned conditional

Conditional (1) 0.15＜φ _1MF/ φ _1MR＜1.0:0.421

Conditional (2)-3.0＜φ _1PF/ φ _1PR＜-1.0:-1.792

Conditional (3) 15＜(φ 3/ φ 4)＜320:27.776077

Conditional (4)-10＜(R _3r+ R _4f)/(R _3r-R _4f)＜0:-7.257263

Conditional (5) 1＜ds/dt＜1.5:1.0589041

Conditional (6) 6≤N≤9:7

Conditional (7) n _2pave>=1.59:1.685

Conditional (8) v _2r≤35:53.385

Conditional (9) n _3ave>=1.48:1.531

Conditional (10) v _3ave>=60:55.8

Conditional (11) n ₄>=1.48:1.525

Conditional (12) v ₄>=60:55.78

Conditional (13) 0.7＜y ₀₇/ (f _wTan ω _07w)＜1.5:0.921

[embodiment 3]

Optical texture when Fig. 5 is the infintie object point focusing of the zoom lens that relates to of expression present embodiment, along the sectional view of optical axis, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.Fig. 6 is spherical aberration, astigmatism, the distortion aberration in infintie object point when focusing of expression zoom lens shown in Figure 5, the figure of ratio chromatism,, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

At first, use Fig. 5 that the optical texture of the zoom lens of present embodiment is described.The zoom lens of present embodiment disposes the 1st lens combination G of negative power successively from object side on optical axis L c ₁, positive light coke the 2nd lens combination G ₂, positive light coke the 3rd lens combination G ₃With the 4th lens combination G ₄And, at the 1st lens combination G ₁With the 2nd lens combination G ₂Between dispose brightness diaphragm S.In addition, at the 4th lens combination G ₄The picture side, dispose the flat low-pass filter LF in plane, plane flat CCD cloche CG successively, have the CCD of shooting face IM from object side.

The 2nd lens combination G ₂From object side is that aspheric biconvex lens is the lens L of positive light coke by the two sides successively ₂₁, and convex surface be the lens L of negative power towards the meniscus lens of object side ₂₂Constitute.

The 4th lens combination G ₄Only be the lens L of negative power by meniscus lens ₄Constitute, the face of its object side is an aspheric surface, and convex surface is towards the picture side.

The face data

Aspherical surface data

Various data

The zoom lens group data

Data based on above-mentioned conditional

Conditional (1) 0.15＜φ _1MF/ φ _1MR＜1.0:0.411

Conditional (2)-3.0＜φ _1PF/ φ _1PR＜-1.0:-2.262

Conditional (3) 15＜(φ 3/ φ 4)＜320:17.834033

Conditional (4)-10＜(R _3r+ R _4f)/(R _3r-R _4f)＜0:-5.547386

Conditional (5) 1＜ds/dt＜1.5:1.0752665

Conditional (6) 6≤N≤9:6

Conditional (7) n _2pave>=1.59:1.582

Conditional (8) v _2n≤35:59.4

Conditional (9) n _3ave>=1.48:1.531

Conditional (10) v _3ave>=60:55.8

Conditional (11) n ₄>=1.48:1.525

Conditional (12) v ₄>=60:55.78

Conditional (13) 0.7＜y ₀₇/ (f _wTan ω _07w)＜1.5:0.932

[embodiment 4]

Optical texture when Fig. 7 is the infintie object point focusing of the zoom lens that relates to of expression present embodiment, along the sectional view of optical axis, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.Fig. 8 is spherical aberration, astigmatism, the distortion aberration in infintie object point when focusing of expression zoom lens shown in Figure 7, the figure of ratio chromatism,, the state of expression (a) wide-angle side, (b) intermediateness, (c) telescope end respectively.

At first, use Fig. 7 that the optical texture of the zoom lens of present embodiment is described.The zoom lens of present embodiment disposes the 1st lens combination G of negative power successively from object side on optical axis L c ₁, positive light coke the 2nd lens combination G ₂, positive light coke the 3rd lens combination G ₃With the 4th lens combination G ₄And, at the 1st lens combination G ₁With the 2nd lens combination G ₂Between dispose brightness diaphragm S.In addition, at the 4th lens combination G ₄The picture side, dispose the flat low-pass filter LF in plane, plane flat CCD cloche CG successively, have the CCD of shooting face IM from object side.

The 4th lens combination G ₄Towards meniscus lens the lens L of positive light coke only as side by convex surface ₄Constitute.

And, from wide-angle side when telescope end becomes times, the 1st lens combination G ₁At first move to the picture side, move to object side then, so to-and-fro movement on optical axis L c.The 2nd lens combination G ₂With brightness diaphragm S, on optical axis L c, move to object side, reduce simultaneously and the 1st lens combination G ₁The interval.The 3rd lens combination G ₃Enlarging and the 2nd lens combination G ₂The interval time, at first move to the picture side, move to object side then, so to-and-fro movement on optical axis L c.The 4th lens combination G ₄Enlarging and the 3rd lens combination G ₃The interval time, only from wide-angle side when intermediateness becomes times to the picture side shifting.

The face data

Aspherical surface data

Various data

The zoom lens group data

Data based on above-mentioned conditional

Conditional (1) 0.15＜φ _1MF/ φ _1MR＜1.0:0.435

Conditional (2)-3.0＜φ _1PF/ φ _1PR＜-1.0:-2.397

Conditional (3) 15＜(φ 3/ φ 4)＜320:313.20683

Conditional (4)-10＜(R _3r+ R _4f)/(R _3r-R _4f)＜0:-4.778565

Conditional (5) 1＜ds/dt＜1.5:1.206884

Conditional (6) 6≤N≤9:7

Conditional (7) n _2pave>=1.59:1.699

Conditional (8) v _2n≤35:53.01

Conditional (9) n _3ave>=1.48:1.554

Conditional (10) v _3ave>=60:60.71

Conditional (11) n ₄>=1.48:1.525

Conditional (12) v ₄>=60:55.78

Conditional (13) 0.7＜y ₀₇/ (f _wTan ω _07w)＜1.5:0.930

In addition, in above-mentioned each embodiment, aperture diaphragm S is configured in the object side of the 2nd lens combination, as long as but can move integratedly with the 2nd lens combination, for example also can be configured between the lens that constitute the 2nd lens combination.And, in above-mentioned each embodiment, the structure of taking zoom lens to constitute, but the invention is not restricted to this structure by 4 lens combination, also can be in the 4th lens combination also dispose lens combination as side.

And zoom lens of the present invention can also be according to following said formation.

Zoom lens of the present invention except that the brightness diaphragm, can also dispose glare stop in order to end to fall unwanted light such as ghost image/dazzle.In addition, the allocation position of glare stop can be in the arbitrary position between object side, the 1st lens combination and the 2nd lens combination of the 1st lens combination, between the 2nd lens combination and the 3rd lens combination, between the 3rd lens combination and the 4th lens combination, between the 4th lens combination and the shooting face.And glare stop also can use frame parts to constitute, and can also use miscellaneous part to constitute.In addition, glare stop also can constitute through directly on optics, printing, and can also use formations such as coating or adhering and sealing parts.And the Any shape such as shape that the shape of glare stop can be circle, ellipse, rectangle, polygon, surrounded by function curve.And glare stop not only ends to fall harmful light beam, can also end to fall the light beam of the comet aberration (coma flare) etc. of picture periphery.

And, also can implement anti-reflection coating to each lens of zoom lens of the present invention, alleviate ghost image, dazzle.During this situation, in order effectively to alleviate ghost image/dazzle, the preferred anti-reflection coating of implementing is a laminated coating.And, also can be low-pass filter be implemented the IR-cut coating, and the lens face of each lens, cloche etc. is implemented the IR-cut coating.

In addition, in order to prevent ghost image/dazzle, generally on the air surface of contact of lens, implement anti-reflection coating.On the other hand, in the composition surface that engages lens, the refractive index of bonding agent is compared very high with the refractive index of air.Therefore, it is more in the majority than the situation of its little reflectivity that the composition surface of joint lens adopts original signal layer coating perhaps to form, and the situation of specially implementing coating is less.But, if also actively implement anti-reflection coating, then can further alleviate ghost image/dazzle on the composition surface that engages lens, can obtain more preferable image.

Especially in recent years the respond well glass of high refractive index material of aberration correction is popularized, thus be applied to camera with in the optical system more, but when being used as the joint lens to the glass of high refractive index material, the reflection on the composition surface can not be ignored.In this case, it is effective especially anti-reflection coating to be implemented on the composition surface.

About effective method of application of this composition surface coating, in instructions of No. the 7116482nd, japanese kokai publication hei 2-27301 communique, TOHKEMY 2001-324676 communique, TOHKEMY 2005-92115 communique, USP etc., have disclosed.As employed coating material, according to as the refractive index of the lens of base material and the refractive index of bonding agent, can suitably selective refraction rate than higher Ta ₂O ₅, TiO ₂, Nb ₂O ₅, ZrO ₂, HfO ₂, CeO ₂, SnO ₂, In ₂O ₃, ZnO, Y ₂O ₃Deng coating material, and the lower MgF of refractive index ratio ₂, SiO ₂, Al ₂O ₃Deng coating material, and be set at the thickness that satisfies phase condition and get final product.

Certainly, identical with coating on the air surface of contact of camera lens, also can make the composition surface coating form laminated coating.Coating material and thickness through the two-layer or two-layer above film number of appropriate combination can further reduce the control of reflectivity, the dichroism of carrying out reflectivity and angular characteristics etc. etc.And about the lens composition surface beyond the 1st lens combination, it is also effective certainly to carry out the composition surface coating based on identical thought.

And; Under the situation of zoom lens of the present invention; Preferably be used to carry out the focusing of focal adjustments, but also can carry out, can also in a plurality of lens combination, carry out in the arbitrary lens combination in the 1st lens combination, the 2nd lens combination, the 4th lens combination in the 3rd lens combination.And this focusing can be carried out through zoom lens integral body is moved, and a part of lens is moved carry out.

And zoom lens of the present invention can alleviate the lowering of luminance of image periphery through making the micro lens displacement of CCD.For example, can change the design of the micro lens of CCD according to the incident angle of the light in each image height degree.And, the lowering of luminance amount that also can come the correcting image periphery through Flame Image Process.

Above-described zoom lens of the present invention can be applied to especially be applied to digital camera and video camera etc. through the camera that the object that forms via zoom lens is looked like image in imaging apparatuss such as CCD to be photographed.Its concrete example below is shown.

Fig. 9, Figure 10 and Figure 11 are the synoptic diagram that the structure of digital camera of the present invention has been used in expression; Fig. 9 is the stereographic map when the place ahead is watched of the outward appearance of expression digital camera; Figure 10 is the front view when the rear is watched of this digital camera, and Figure 11 is the perspective plan view that schematically illustrates the structure of digital camera.Wherein, Fig. 9 and Figure 10 are the non-figure when folding of expression zoom lens.

Digital camera 10 comprise be disposed at photography with the zoom lens on the light path 12 11, be disposed at view finder and change button 27 and setting alternation switch 28 etc. with the finder optical system on the light path 14 13, shutter release button 15, flashlamp illuminating part 6, LCD monitor 17, focal length.And when zoom lens 11 folded, cover 26 slided and also covers zoom lens 11 and finder optical system 13.

When opening cover 26 and be set at photography state to digital camera 10, zoom lens 11 becomes non-folded state shown in Figure 9.When under this state, pushing the shutter release button 15 that is configured in digital camera 10 tops,, photograph through zoom lens 11, for example embodiments of the invention 1 described zoom lens with this action interlock.The object picture is via zoom lens 11, low-pass filter LF and cloche CG, is formed on the imaging surface as the CCD 18 of solid-state image pickup.The image information of the object picture that on the imaging surface of this CCD18, forms images is recorded in the record cell 21 through processing unit 20.And institute's images recorded information is processed unit 20 and takes out, and can be used as electronic image and is presented on the LCD monitor 17 of being located at the camera back side.

In addition, dispose view finder with objective lens optical system 22 at view finder on light path 14.View finder is made up of a plurality of lens combination (among the figure being 3 groups) and two prisms with objective lens optical system 22, changes focal length with zoom lens 11 interlocks.This view finder forms the object picture with objective lens optical system 22 on as the visual field frame 24 of the erecting prism 23 of erect image parts.And, dispose the eyepiece optical system 25 that the picture that forms erect image is directed to observer's eyeball E at the rear of this erecting prism 23.In addition, the emitting side at eyepiece optical system 25 disposes cap assembly 19.

In the digital camera 10 that constitutes like this, zoom lens 11 has the hypermutation multiple proportions, and small-sized, can fold and take in, so can guarantee superperformance, and realize the miniaturization of digital camera 10.

Claims

1. a zoom lens is characterized in that,

Have the 1st lens combination of negative power, the 2nd lens combination of positive light coke, the 3rd lens combination and the 4th lens combination of positive light coke successively from object side,

From wide-angle side when telescope end becomes times, the interval of said the 1st lens combination and said the 2nd lens combination diminishes, the interval of said the 2nd lens combination and said the 3rd lens combination becomes big simultaneously,

Said the 1st lens combination near the lens of picture side and said the 2nd lens combination near the picture lens of side between, have the brightness diaphragm mobile integratedly with said the 2nd lens combination,

Said the 1st lens combination is made up of the 1st lens of the negative power that is disposed at object side and the 2nd lens that are disposed at as the positive light coke of side,

And the formula that meets the following conditions (1), (2),

0.15＜φ _1MF/φ _1MR＜1.0......(1)

-3.0＜φ _1PF/φ _1PR＜-1.0......(2)

2. zoom lens according to claim 1 is characterized in that, the two sides of the 1st lens of the negative power of said the 1st lens combination is an aspheric surface.

3. a zoom lens is characterized in that,

Said the 3rd lens combination and said the 4th lens combination only are made up of the meniscus lens of concave surface towards object side respectively.

4. zoom lens according to claim 3 is characterized in that, the formula that meets the following conditions (3),

15＜(φ3/φ4)＜320......(3)

5. zoom lens according to claim 3 is characterized in that, the formula that meets the following conditions (4),

-10＜(R _3r+R _4f)/(R _3r-R _4f)＜0......(4)

6. according to each described zoom lens in the claim 3～5, it is characterized in that, the formula that meets the following conditions (5),

1＜ds/dt＜1.5......(5)

7. according to claim 1 or 3 described zoom lens, it is characterized in that, the formula that meets the following conditions (6),

6≤N≤9......(6)

Wherein, N refers to the lens total quantity of said zoom lens.

8. according to claim 1 or 3 described zoom lens, it is characterized in that said the 2nd lens combination is made up of the lens below 3.

9. according to claim 1 or 3 described zoom lens, it is characterized in that said the 2nd lens combination is by the lens of positive light coke and the lens of the lens of positive light coke and negative power are engaged the joint lens that obtain constitute.

10. according to claim 1 or 3 described zoom lens; It is characterized in that; The lens that said the 2nd lens combination has the lens of positive light coke and negative power engage the joint lens that obtain, and the Abbe number of the lens of the negative power of said joint lens is less than the Abbe number of the lens of the positive light coke of said joint lens.

11. zoom lens according to claim 9 is characterized in that, the formula that meets the following conditions (7), (8),

n _2pave≥1.59......(7)

υ _2n≤35......(8)

Wherein, n _2paveThe mean value of the refractive index of the lens of the whole positive light coke that refers to comprise in said the 2nd lens combination, υ _2nThe Abbe number of the lens of the negative power that refers to comprise in said the 2nd lens combination.

12. zoom lens according to claim 9 is characterized in that, constitutes interval between the lens of said the 2nd lens combination less than the center thickness of the lens of the negative power that comprises in said the 2nd lens combination.

13. according to claim 1 or 3 described zoom lens, it is characterized in that, the formula that meets the following conditions (9), (10),

n _3ave≥1.48......(9)

υ _3ave≥60......(10)

14., it is characterized in that said the 3rd lens combination is made up of the aspheric lens with at least more than one according to claim 1 or 3 described zoom lens.

15., it is characterized in that said the 3rd lens combination is made up of resin lens according to claim 1 or 3 described zoom lens.

16., it is characterized in that said the 4th lens combination is made up of lens according to claim 1 or 3 described zoom lens, and the formula that meets the following conditions (11), (12),

n ₄≥1.48......(11)

υ ₄≥60......(12)

17., it is characterized in that said the 4th lens combination is made up of the aspheric lens with at least more than one according to claim 1 or 3 described zoom lens.

18., it is characterized in that said the 4th lens combination is made up of resinous lens according to claim 1 or 3 described zoom lens.

19., it is characterized in that said the 4th lens combination does not move according to claim 1 or 3 described zoom lens when becoming times.

20. electronic image pickup device; It has zoom lens, is configured near electro-photographic element, graphics processing unit and the record cell of image space of said zoom lens; Said graphics processing unit is processed the view data that is obtained by said electro-photographic element, makes its alteration of form, and is recorded in the said record cell; Said electronic image pickup device is characterised in that

Said zoom lens is each described zoom lens in the claim 1～19,

When roughly infintie object point is focused, the formula that meets the following conditions (13),

0.7＜y ₀₇/(f _w·tanω _07w)＜1.5......(13)

Wherein, (in the face that can make a video recording) distance (maximum image height) from the center to the solstics is made as y in effective shooting face of said electro-photographic element ₁₀The time, utilize y ₀₇=0.7y ₁₀Represent ω _07wFinger and the center from the shooting face of wide-angle side are connected to y ₀₇The object point direction of the picture point correspondence of position is with respect to the angle of optical axis; f _wThe expression imaging system is at the focal length of wide-angle side.