CN103217786A - Telescope zoom lens - Google Patents

Abstract

The invention discloses a telescope zoom lens. A first lens group, a second lens group, a third lens group and a fourth lens group are arranged from an object side to an imaging side sequentially along an optical axis, and the refraction capacities of the first lens group, the second lens group, the third lens group and the fourth lens group are positive, negative, positive and positive respectively. The first lens group is fixedly arranged at a first specific position, the second lens group moves back and forth along the optical axis following the changes of the amplification power of the zoom lens, the third lens group is fixedly arranged at a second specific position, and the fourth lens group moves along the optical axis to keep an imaging plane produced by the zoom lens being accurately projected on an image recorder. Therefore, the amplification power of the zoom lens can reach 20 times (X), in a zoom process, the first lens group and the third lens group are in a condition of rest, and only the second lens group and the fourth group move.

Description

Telephoto zoom lens

Technical field

The present invention refers to a kind of digital camera (DV), digital camera (DSC), panel computer of can be applicable to especially relevant for a kind of telephoto zoom lens ... Deng in the hand-held electronic product or CCTV Closed Circuit Television Camera, safety monitoring system ... Deng the high magnification telephoto zoom lens in the video capturing device.

Background technology

The video camera that is applied to shoot often needs to see through zoom lens the small items in the distant view is amplified to the picture of profile, and this action has become important Techniques for Photography.In the closed-circuit television system of security monitoring, also need scenery with long distance be amplified to can the identification appearance sharp image, so in the capture mirror group of CCTV Closed Circuit Television Camera and safety monitoring system, need to use telephoto zoom lens with high enlargement ratio.

In telephoto lens, just may produce bigger enlargement ratio image because focal length is long, also because need very long focal length, institute is so that the length overall of lens system also is a length.Because take the image of wide-angle side into account, the aperture of first group of mirror group generally also is bigger, that is to say that the volume of whole binoculars head is bigger.

At first, U.S. Pat 7,532,411 have disclosed the zoom system, pancreatic system that a kind of 4 groups of refractive power are PNPP (positive and negative just), and it possesses the doubly function of (10X) of hypermutation is arranged, but should before case 4 mirror groups 4 mirror groups in the process of zoom displacement all be arranged, so framework no doubt can obtain good image quality, yet the spoke face effective diameter of first group of mirror group is the maximum in the lens system, with the mirror group driving of this massiveness, must be the work of a power consumption.

Moreover the clear 50-26931 of Japan special permission communique JP has disclosed a kind of 5 groups of zoom system, pancreatic systems that refractive power is PNPNP, and wherein the 2nd, the 4 group of mirror group are that optical compensation mode with interlock keeps image on same focusing surface.In addition, the mechanical compensation Zoom structure that it is PNPP that the Japan clear 45-08840 of special permission communique JP has disclosed a kind of 4 groups of refractive power, but wherein have the 1st, 2,3,4 group of mirror groups to be all the groups of motion, be disadvantageous for manufacturing cost.

In addition, the Japan clear 46-32989 of special permission communique JP also discloses a kind of doubly zoom design of (15X) of hypermutation of reaching, and it is 4 groups of structures that refractive power is PNNP, and wherein the 2nd, 3 group of mirror group motions are to reach the Zoom structure of mechanical compensation.Moreover, U.S. Pat 5,815,322 adopt the design of interior focusing, also can reach the doubly zoom design of (20X) of hypermutation, but should preceding case be to adopt the framework of PNNP.In addition, U.S. Pat 7,672,061 adopts the design of interior focusing, also can reach the doubly zoom design of (22X) of hypermutation, but should preceding case be to adopt the framework of PNNP.

Summary of the invention

For solving the aforementioned problems in the prior, the object of the present invention is to provide a kind of telephoto zoom lens, it adopts 4 groups of refractive power to be the lens group of PNPP in regular turn, belongs to a kind of mechanical compensation Zoom lens structure of interior focusing formula.

The present invention is a kind of telephoto zoom lens of being provided of an embodiment wherein, and it comprises: the second lens group, that first a lens group, with positive refractive power has a negative refractive power has the 3rd lens group, and the 4th lens group with positive refractive power of positive refractive power.The above-mentioned first lens group with positive refractive power is fixed on one first ad-hoc location.Above-mentioned have the second lens group of negative refractive power along with the change of the enlargement ratio of telephoto zoom lens is moved with the optical axis along telephoto zoom lens.Above-mentioned the 3rd lens group with positive refractive power is fixed on one second ad-hoc location.Above-mentioned the 4th lens group with positive refractive power moves along the optical axis of telephoto zoom lens, accurately is incident upon on the Video Recorder to keep the imaging surface that telephoto zoom lens was produced.The first lens group, the second lens group, the 3rd lens group, and the 4th lens group arrange in regular turn towards the direction of imaging side along optical axis and from the object side of telephoto zoom lens, and the first lens group, the second lens group, the 3rd lens group, and the focal length of the 4th lens group need meet following two set conditions:

Condition (1): $6<\left|\frac{F_1}{F_2}\right|<10;$ And

Condition (2): $2<\left|\frac{F_1}{F_3}\right|<3;$

Wherein, F ₁Be the focal length of the first lens group, F ₂Be the focal length of the second lens group, F ₃It is the focal length of the 3rd lens group.

Therefore, beneficial effect of the present invention includes at least:

1, the present invention can provide the capture zoom lens of a kind of hypermutation multiple proportions, long-focus and high image quality.

2, the present invention can design and make a kind of high-quality, first lens group has suitable spoke face diameter and enlargement ratio can reach the capture zoom lens of 20X.

For enabling further to understand feature of the present invention and technology contents, see also following about detailed description of the present invention and accompanying drawing, yet appended graphic only provide with reference to and explanation usefulness, be not to be used for to the present invention's limitr in addition.

Description of drawings

Figure 1A shows the lens configuration synoptic diagram of each lens group under the wide-angle side kenel of the telephoto zoom lens of first embodiment of the invention.

Figure 1B shows the lens configuration synoptic diagram of each lens group under the normal place kenel of the telephoto zoom lens of first embodiment of the invention.

Fig. 1 C shows be visible lens configuration synoptic diagram under the far-end kenel of each lens group of the telephoto zoom lens of first embodiment of the invention.

When Fig. 1 D to Fig. 1 F represents respectively that first embodiment is in the wide-angle kenel, during the normal place kenel and the curve map of longitudinal spherical aberration, astigmatism and distortion when looking in the distance kenel.

Fig. 2 A shows the lens configuration synoptic diagram of each lens group under the wide-angle side kenel of the telephoto zoom lens of second embodiment of the invention.

Fig. 2 B shows the lens configuration synoptic diagram of each lens group under the normal place kenel of the telephoto zoom lens of second embodiment of the invention.

Fig. 2 C shows be visible lens configuration synoptic diagram under the far-end kenel of each lens group of the telephoto zoom lens of second embodiment of the invention.

When Fig. 2 D to Fig. 2 F represents respectively that second embodiment is in the wide-angle kenel, during the normal place kenel and the curve map of longitudinal spherical aberration, astigmatism and distortion when looking in the distance kenel.

Wherein, description of reference numerals is as follows:

First lens group: the G1

First lens: L ₁₁

Second lens: L ₁₂

Cemented doublet: L _{1_12}

The 3rd lens: L ₁₃

The 4th lens: L ₁₄

Second lens group: the G2

First lens: L ₂₁

Second lens: L ₂₂

The 3rd lens: L ₂₃

Cemented doublet: L _{2_23}

The 3rd lens group: G3

First lens: L ₃₁

Second lens: L ₃₂

The 3rd lens: L ₃₃

The 4th lens group: G4

First lens: L ₄₁

Second lens: L ₄₂

Cemented doublet: L _{4_12}

Optical surface: S1 to S24

Axial distance: D1 to D24

Diaphragm: A

Video Recorder: I

Optical axis: Z

Embodiment

(first embodiment)

See also shown in Figure 1A to Fig. 1 C, it shows the lens configuration synoptic diagram of each lens group under wide-angle side (Wide), normal place (Normal) and three kinds of kenels of telescope end (Tele) of the telephoto zoom lens of first embodiment of the invention respectively, wherein the D1 to D24 among Figure 1A represents the axial distance between each optical surface, and the S 1 to S24 among Figure 1B is the optical surface numbering of each eyeglass.

The telephoto zoom lens of first embodiment of the invention can be made up of 12 lens.By disclosed each eyeglass combination configuration relation among Figure 1A to Fig. 1 C as can be known, the telephoto zoom lens of first embodiment of the invention includes: one first G1 of lens group, one second G2 of lens group, one the 3rd G3 of lens group, and one the 4th G4 of lens group, wherein first G1 of lens group, the 3rd G3 of lens group, and the 4th G4 of lens group all have positive refractive power, and second G2 of lens group has negative refractive power.Utilize first G1 of lens group, second G2 of lens group, the 3rd G3 of lens group, and each other interval variation of the 4th G4 of lens group (also promptly by changing between said lens group spacing), can change the focal length of this telephoto zoom lens along optical axis Z direction.

In the first embodiment of the present invention, first G1 of lens group includes one first lens L ₁₁, one second lens L ₁₂, one the 3rd lens L ₁₃, and one the 4th lens L ₁₄, the first lens L wherein ₁₁, the second lens L ₁₂, the 3rd lens L ₁₃, and the 4th lens L ₁₄Can arrange in regular turn towards the direction of imaging side along optical axis Z and from object side, and the first lens L ₁₁With the second lens L ₁₂Can glue together mutually to form a cemented doublet L _{1_12}Moreover second G2 of lens group comprises one first lens L ₂₁, one second lens L ₂₂, and one the 3rd lens L ₂₃, the first lens L wherein ₂₁, the second lens L ₂₂, and the 3rd lens L ₂₃Can arrange in regular turn towards the direction of imaging side along optical axis Z and from object side, and the second lens L ₂₂With the 3rd lens L ₂₃Can glue together mutually to form a cemented doublet L _{2_23}In addition, the 3rd G3 of lens group comprises one first lens L ₃₁, one second lens L ₃₂, and one the 3rd lens L ₃₃, and the first lens L ₃₁, the second lens L ₃₂, and the 3rd lens L ₃₃Can arrange in regular turn towards the direction of imaging side along optical axis Z and from object side.In addition, the 4th G4 of lens group comprises one first lens L ₄₁And one second lens L ₄₂, the first lens L wherein ₄₁With the second lens L ₄₂Can glue together mutually to form a cemented doublet L _{4_12}, and the first lens L ₄₁And the second lens L ₄₂Can arrange in regular turn towards the direction of imaging side along optical axis Z and from object side.Moreover telephoto zoom lens can further comprise: one along optical axis Z and be arranged at second G2 of lens group and the 3rd G3 of lens group between diaphragm A, and the big I of diaphragm A is adjusted along with the needs that use.

In other words, above-mentioned first G1 of lens group with positive refractive power can be fixed on one first ad-hoc location.Above-mentioned second G2 of lens group with negative refractive power can move with the optical axis Z along telephoto zoom lens along with the change of the enlargement ratio of telephoto zoom lens.Above-mentioned the 3rd G3 of lens group with positive refractive power can be fixed on one second ad-hoc location.Above-mentioned the 4th G4 of lens group with positive refractive power can move along the optical axis Z of telephoto zoom lens, accurately is incident upon on the Video Recorder I to keep the imaging surface that telephoto zoom lens was produced.In addition, first G1 of lens group, second G2 of lens group, the 3rd G3 of lens group, and the 4th G4 of lens group can arrange in regular turn towards the direction of imaging side along optical axis Z and from the object side of telephoto zoom lens.For instance, as described below:

(1), first G1 of lens group, second G2 of lens group, the 3rd G3 of lens group, and the focal length of the 4th G4 of lens group need meet following two set conditions:

Condition (1): $6<\left|\frac{F_1}{F_2}\right|<10;$ And

Condition (2): $2<\left|\frac{F_1}{F_3}\right|<3;$

Wherein, F ₁Be the focal length of the first lens group, F ₂Be the focal length of the second lens group, F ₃It is the focal length of the 3rd lens group.

(2), the distance of the focal length of first G1 of lens group and first G1 to the of lens group, three G3 of lens group need meet following condition:

$1<\left|\frac{F_1}{d_{1-3}}\right|<1.2,$

Wherein, d _1-3It is the distance of first G1 to the of lens group, three G3 of lens group.

(3), the 3rd lens L of first G1 of lens group ₁₃With the 4th lens L ₁₄All can be an one chip meniscus shaped lens, and the cemented doublet L of first G1 of lens group _{1_12}And the 3rd lens L ₁₃Focal length need meet following condition:

$2<|F_{1\_12}\&times;(\frac{1}{F_{13}}+\frac{1}{F_{14}})|<4,$

Wherein, F _{1_12}Be the cemented doublet L of first G1 of lens group _{1_12}Focal length, F ₁₃Be the 3rd lens L of first G1 of lens group ₁₃Focal length.

(4), the first lens L of second G2 of lens group ₂₁Can be one chip lens, and the first lens L of second G2 of lens group ₂₁With cemented doublet L _{2_23}Focal length need meet following condition:

$0.6<\left|\frac{F_{21}}{F_{2\_23}}\right|<0.8,$

Wherein, F ₂₁Be the first lens L of second G2 of lens group ₂₁Focal length, F _{2_23}Be the cemented doublet L of second G2 of lens group _{2_23}Focal length.

(5), the focal length of the focal length of the 3rd G3 of lens group and the 4th G4 of lens group need meet following condition:

$0.7<\left|\frac{F_4}{F_3}\right|<1.2,$

Wherein, F ₃Be the focal length of the 3rd G3 of lens group, F ₄It is the focal length of the 4th G4 of lens group.

See also shown in Fig. 1 D to Fig. 1 F the curve map of longitudinal spherical aberration, astigmatism and distortion when Fig. 1 D represents that first embodiment is in the wide-angle kenel; The curve map of longitudinal spherical aberration, astigmatism and distortion when Fig. 1 E represents that first embodiment is in the normal place kenel; Fig. 1 F represents that first embodiment is in the curve map of longitudinal spherical aberration, astigmatism and distortion when looking in the distance kenel.

The data of first embodiment of the invention please refer to shown in the following table, wherein R represents the radius-of-curvature (numbering is by S1 to S24) of each lens surface, D represents the axial distance (numbering is by D1 to D24) between each optical surface, nd represents the refractive index of each optical surface, Vd represents the Abbe number (Abbe number) of each optical surface, the numerical value of chromatic dispersion (chromatic dispersion) characteristic of its expression material.

Focal length, f-number, field angle and position D7, D12, D19 distinguish as follows with D22 with respect to the relation of different zoom positions:

	Wide	Normal	Tele	Unit
					f	6.3	29	121	mm
F NO	2.6	3.3	3.6
					FOV(ω)	29°	6.8°	1.65°
D7	1.19	25.16	35.62	mm
					D12	37.08	13.11	2.65	mm
D19	8.00	2.99	13.17	mm
					D22	8.11	13.12	2.94	mm

Wherein f represents the system's focal length corresponding to wide-angle side, normal end and telescope end, F _NOExpression is corresponding to the f-number of wide-angle side, normal end and telescope end, and FOV (ω) expression is corresponding to the field angle of wide-angle side, normal end and telescope end.

Moreover in above-mentioned a plurality of lens, optical surface numbering S18 and S19 are aspheric surface, and its asphericity coefficient data is as follows respectively:

The surface

K

A 4

A 6

A 8

A 10

A 12

A 14

A 16

S18

5.16

-3.13E-04

5.19E-06

-3.03E-06

3.54E-07

-1.97E-08

3.72E-10

-8.65E-13

S19

71.59

-6.49E-05

8.13E-07

-5.69E-07

4.22E-08

-5.12E-10

-1.04E-10

3.66E-12

Above-mentioned aspheric surface equation can be expressed as:

$Z=\frac{{\mathrm{CY}}^2}{1+\sqrt{1-(K+1)C^2{Y}^2}}+\underset{2}{\overset{8}{\mathrm{\&Sigma;}}}{A}_{2n}{Y}^{2n};$

Wherein, the Z value is sag (sag), C (=1/R) be spheric curvature, K is the constant of the cone, Y is the height vertical with lens axis Z, A ₄Be 4 rank asphericity coefficients, A ₆Be 6 rank asphericity coefficients, A ₈To A ₁₆Representative then the rest may be inferred.

(second embodiment)

See also shown in Fig. 2 A to Fig. 2 C, it shows the lens configuration synoptic diagram of each lens group under wide-angle side (Fig. 2 A), normal place (Fig. 2 B) and three kinds of kenels of telescope end (Fig. 2 C) of the telephoto zoom lens of second embodiment of the invention respectively.See also shown in Fig. 2 D to Fig. 2 F, the curve map of longitudinal spherical aberration, astigmatism and distortion when Fig. 2 D represents that second embodiment is in the wide-angle kenel, the curve map of longitudinal spherical aberration, astigmatism and distortion when Fig. 2 E represents that second embodiment is in the normal place kenel, Fig. 2 F represents that second embodiment is in the curve map of longitudinal spherical aberration, astigmatism and distortion when looking in the distance kenel.

The data of second embodiment of the invention please refer to shown in the following table:

Focal length, f-number, field angle and position D7, D12, D19 distinguish as follows with D22 with respect to the relation of different zoom positions:

	Wide	Normal	Tele	Unit
					f	6.3	29	121	mm
F NO	2.27	3.00	2.98
					FOV(ω)	29°	6.8°	1.65°
D7	1.19	25.16	35.62	mm
					D12	35.18	11.21	0.75	mm
D19	8.22	3.40	13.20	mm
					D22	7.89	12.71	2.91	mm

Moreover in above-mentioned a plurality of lens, optical surface numbering S18 and S19 are aspheric surface, and the aspheric surface equation is identical with first embodiment of the invention.The asphericity coefficient data of second embodiment is as follows respectively:

The surface

K

A4

A6

A8

A10

A12

A14

A16

S18

5.32

-3.47E-04

7.48E-06

-3.38E-06

3.15E-07

-1.63E-08

4.00E-10

-3.68E-12

S19

65.94

-6.13E-05

1.52E-06

-7.98E-07

5.38E-08

-5.97E-11

-1.20E-10

3.23E-12

(the possible effect of embodiment)

In sum, beneficial effect of the present invention includes at least:

1, the present invention can provide the capture zoom lens of a kind of hypermutation multiple proportions, long-focus and high image quality.

2, the present invention can design and make a kind of high-quality, first lens group has suitable spoke face diameter and enlargement ratio can reach the capture zoom lens of 20X.

The above only is a preferable possible embodiments of the present invention, and is non-so limit to claim of the present invention, so the equivalence techniques that uses instructions of the present invention and graphic content to do such as changes, all is contained in the scope of the present invention.

Claims (5)

1. a telephoto zoom lens is characterized in that, comprising:

One has the first lens group of positive refractive power, and it is fixed on one first ad-hoc location;

One has the second lens group of negative refractive power, and its change along with the enlargement ratio of this telephoto zoom lens is moved with the optical axis along this telephoto zoom lens;

One has the 3rd lens group of positive refractive power, and it is fixed on one second ad-hoc location; And

One has the 4th lens group of positive refractive power, and its optical axis along this telephoto zoom lens moves, and accurately is incident upon on the Video Recorder with the imaging surface that keeps this telephoto zoom lens to be produced;

Wherein, this first lens group, this second lens group, the 3rd lens group, and the 4th lens group arrange in regular turn towards the direction of imaging side along this optical axis and from the object side of this telephoto zoom lens, and this first lens group, this second lens group, the 3rd lens group, and the focal length of the 4th lens group need meet following two set conditions:

Condition (1): $6<\left|\frac{F_1}{F_2}\right|<10;$ And

Condition (2): $2<\left|\frac{F_1}{F_3}\right|<3;$

Wherein, F ₁Be the focal length of this first lens group, F ₂Be the focal length of this second lens group, F ₃Focal length for the 3rd lens group.

2. telephoto zoom lens as claimed in claim 1 is characterized in that, the focal length of this first lens group and this first lens group need meet following condition to the distance of the 3rd lens group:

$1<\left|\frac{F_1}{d_{1-3}}\right|<1.2;$

Wherein, d _1-3Be the distance of this first lens group to the 3rd lens group.

3. telephoto zoom lens as claimed in claim 1, it is characterized in that, this first lens group comprises one first lens, one second lens, one the 3rd lens, and one the 4th lens, these first lens and this second lens glue together mutually to form a cemented doublet, the 3rd lens and the 4th lens are all an one chip meniscus shaped lens, these first lens, these second lens, the 3rd lens, reach the 4th lens and arrange in regular turn towards the direction of this imaging side, and the focal length of this cemented doublet and the 3rd lens need meet following condition along this optical axis and from this object side:

$2<|F_{1\_12}\&times;(\frac{1}{F_{13}}+\frac{1}{F_{14}})|<4;$

Wherein, F _{1_12}Be the focal length of this cemented doublet of this first lens group, F ₁₃Focal length for the 3rd lens of this first lens group.

4. telephoto zoom lens as claimed in claim 1, it is characterized in that, this second lens group comprises one first lens, one second lens, reaches one the 3rd lens, these first lens are one chip lens, these second lens and the 3rd lens glue together mutually to form a cemented doublet, these first lens, these second lens, and the 3rd lens arrange in regular turn towards the direction of this imaging side along this optical axis and from this object side, and the focal length of these first lens and this cemented doublet need meet following condition:

$0.6<\left|\frac{F_{21}}{F_{2\_23}}\right|<0.8;$

Wherein, F ₂₁Be the focal length of this first lens of this second lens group, F _{2_23}Focal length for this cemented doublet of this second lens group.

5. telephoto zoom lens as claimed in claim 1, it is characterized in that, the 3rd lens group comprises one first lens, one second lens, and one the 3rd lens, and these first lens, these second lens, and the 3rd lens are arranged towards the direction of this imaging side in regular turn along this optical axis and from this object side, wherein the 4th lens group comprises one first lens and one second lens, these first lens and this second lens glue together mutually to form a cemented doublet, these first lens and this second lens are arranged towards the direction of this imaging side in regular turn along this optical axis and from this object side, and the focal length of the focal length of the 3rd lens group and the 4th lens group need meet following condition:

$0.7<\left|\frac{F_4}{F_3}\right|<1.2;$

Wherein, F ₄Focal length for the 4th lens group.

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