CN103777332A - Low-cost dual-band optical zoom lens - Google Patents

Abstract

The invention discloses a low-cost dual-band optical zoom lens, which sequentially comprises a front lens group with negative focal power, a diaphragm and a rear lens group with positive focal power from an object side to an image side, wherein the front lens group comprises a convex-concave first lens with negative focal power, a double-concave second lens with negative focal power and a convex-concave third lens with positive focal power, the rear lens group comprises a double-convex fourth lens with positive focal power, a double-convex fifth lens with positive focal power, a double-concave sixth lens with negative focal power and a double-convex seventh lens with positive focal power, and the fifth lens and the sixth lens are glued assemblies. A variation of a 2.8-10mm focal range is realized through changing the air space between the front lens group and the rear lens group. The lens disclosed by the invention only uses seven lenses, materials of the lenses do not contain expensive lanthanide series glass and ultralow chromatic dispersion glass, has good processing properties, and effectively controls the cost. The lens is designed for a 1/2.7-inch sensor, the resolution achieves mega pixels within the overall focal range, and day and light confocal imaging is realized.

Description

A kind of low cost dual waveband optical zoom lens

Technical field

This patent belongs to optical, mechanical and electronic integration field, relates to a kind of Zoom optic lens, especially cheaply the confocal zoom lens of two waveband.

Background technology

Along with the raising of security precautions, market is more and more higher to the demand of safety monitoring camera lens, in order to meet the clear monitoring to target under visible ray environment and night infrared luminous environment by day simultaneously, need to adopt visible ray and the confocal camera lens of infrared light two waveband.Near the two waveband zoom lens of focal length section 2.8-10mm, is that maximum products is applied in monitoring field at present, is widely used in the public places such as school, factory, supermarket.Reach on the market at present the Related product of the above high definition imaging of mega pixel, conventionally to use eight to nine optical mirror slips, for example be numbered 200910112238.2 Chinese invention patent, " dual waveband optical zoom lens " by name, focal length section is 2.8-10mm, realized day and night high definition imaging of mega pixel, but it has adopted nine eyeglasses, production cost is higher.Use the less product of eyeglass number if can develop, can greatly reduce eyeglass cost and improve efficiency of assembling, there are wide market outlook.

Summary of the invention

The object of this patent is that a kind of optical mirror slip number of design is seven, and visual light imaging and near infrared imaging can be confocal, and can reach the Zoom optic lens of the above high definition imaging of mega pixel.Seven eyeglasses of this camera lens all adopt the relatively low cheap optical glass of domestic refractive index, expensive high-refractivity lanthanide glass and Extra-low Dispersion glass are avoided completely, and each eyeglass all has higher centering coefficient, be easy to mechanical centering edging, have good production process property, from the cost of raw material, processing difficulty and the control of efficiency of assembling three aspects: cost.This lens construction compactness, simple operation, utilization prospect is wide.

For achieving the above object, the technical scheme that this patent adopts is:

A kind of low cost dual waveband optical zoom lens, comprise front lens group Gn, the diaphragm of negative power and be disposed at the rear lens group Gp with positive light coke of front lens group Gn as side, utilize airspace between front lens group Gn and rear lens group Gp to change to realize the zoom of 2.8-10mm; Described front lens group Gn has convex concave first lens L1, double concave the second lens L2 and convex concave the 3rd lens L3 that are arranged in order to image space order by object space, described rear lens group Gp has lenticular the 4th lens L4 being arranged in order to image space order by object space, lenticular the 5th lens L5, double concave the 6th lens L6 and lenticular the 7th lens L7, and the 5th described lens L5 and the 6th lens L6 are gummed assembly; The material that seven lens of this camera lens adopt, all containing expensive lanthanide glass and Extra-low Dispersion glass.

The radius-of-curvature of the focal length of seven optical lenses in this patent optical lens and refractive index and 14 faces thereof meets the following conditions respectively:

-14.5﹤f1﹤-12 1.68﹤n1﹤1.75 24﹤R1﹤65 6.5﹤R2﹤9

-12.4﹤f2﹤-10.4 1.61﹤n2﹤1.67 -23﹤R3﹤-18 9﹤R4﹤13

14.8﹤f3﹤17.5 1.8﹤n3﹤1.88 10﹤R5﹤16 60<|R6|

Diaphragm

16.8﹤f4﹤19.9 1.69﹤n4﹤1.75 12.5﹤R7﹤21 -55﹤R8﹤-28.5

6﹤f5﹤8 1.63﹤n5﹤1.7 7﹤R9﹤10 -9.5﹤R10﹤-6.5

-4.6﹤f6﹤-3.1 1.81﹤n6﹤1.87 -9.5﹤R11﹤-6.5 5.2﹤R12﹤7.3

7.7﹤f7﹤9.2 1.69﹤n7﹤1.74 8.5﹤R13﹤12.8 -16.2﹤R14﹤-10.5

Here, fi represents the focal length of i eyeglass, and unit is millimeter; Ni represents the refractive index of i eyeglass; Ri represents the radius-of-curvature of i minute surface, and unit is millimeter; I=1,2,3 ...

The main optical index of product: focal distance f=2.8-10mm, field angle 2W=137 °-40 °, relative aperture F=1.8.

In visible-range, the high-resolution lens optical transfer function mtf value of making according to such scheme is in the time of 90lp/mm, and center reaches 0.6, and edge reaches 0.5.In whole focal length section, the optical transfer function mtf value of each visual field is all greater than 0.3 at 120lp/mm place, corresponding to 1/2.7 cun of sensor, the pixel value that the image quality of camera lens can adapt to is: 5.74*120*2*3.23*120*2=1168000>1000000, guarantees that the resolving power of camera lens can reach the high image quality that mega pixel is corresponding in whole focal length section.Under the infrared light environment of 850nm, in whole focal length section, the optical transfer function mtf value of each visual field is all greater than 0.3 at 60lp/mm place, has met the requirement of night infrared light confocal imaging.

Accompanying drawing explanation

Accompanying drawing 1 is the optical system schematic diagram of this patent when zoom wide-angle side (focal length 2.8mm).

Accompanying drawing 2 is this patent optical system schematic diagram when zoom telescope end (focal length 10mm).

Accompanying drawing 3 is the first embodiment of this patent spherical aberration, astigmatism, distortion curve figure in the time of zoom wide-angle side.

Accompanying drawing 4 is the first embodiment of this patent spherical aberration, astigmatism, distortion curve figure in the time of zoom telescope end.

Accompanyingdrawing 5 is the second embodiment of this patent spherical aberration, astigmatism, distortion curve figure in the time of zoom wide-angle side.

Accompanying drawing 6 is the second embodiment of this patent spherical aberration, astigmatism, distortion curve figure in the time of zoom telescope end.

Embodiment

A kind of low cost dual waveband optical zoom lens shown in accompanying drawing 1, is made up of front lens group Gn, diaphragm and rear lens group Gp, by changing the airspace of front lens group Gn and rear lens group Gp, realizes the variation of 2.8-10mm focal range.In the time that interval, two groups of front and back is maximum, lens focus is the shortest, is zoom wide-angle side; Close gradually when two groups of front and back, the focal length of camera lens is elongated gradually, until two groups of intervals reach the minimum interval of design, lens focus is now the longest, is zoom telescope end, as shown in Figure 2.

Front lens group Gn has negative power convex concave first lens L1, negative power double concave the second lens L2 and positive light coke convex concave the 3rd lens L3 that are arranged in order to image space order by object space, first lens L1 and the second lens L2 be directly near assembling, the 3rd lens L3 and the second lens L2 by spacer ring near assembling.

Described rear lens group Gp has lenticular the 4th lens L4 of the positive light coke being arranged in order to image space order by object space, lenticular the 5th lens L5 of positive light coke, negative power double concave the 6th lens L6 and lenticular the 7th lens L7 of positive light coke, the 4th lens L4 and the 5th lens L5 by spacer ring near assembling, the 5th lens L5 and the 6th lens L6 gummed, the 7th lens L7 and the 6th lens L6 by spacer ring near assembling.

The wide-angle side that described patent is 2.8mm at focal length, rear cut-off distance is greater than 6.55mm.

The first embodiment:

The optical data of camera lens is as follows:

Face R d n

1 38.146 0.8 1.70

2 7.682 4.88

3 -20.682 0.7 1.63

4 10.961 0.75

5 13.316 2.57 1.85

6 219.89 (d6)

Diaphragm S ∞ (ds)

7 19.799 1.8 1.72

8 -36.667 0.12

9 8.232 3.8 1.67

10 -8.11 2.58 1.85

11 6.124 0.78

12 11.901 2.25 1.72

13 -11.901

Here, R represents the radius-of-curvature of corresponding minute surface, and d represents center thickness or the airspace of corresponding eyeglass, and n represents the refractive index of corresponding eyeglass, and d6 and ds are variable airspaces, and the variation range of d6 is 14.15-0.69, and the variation range of ds is 7.37-0.83.

The second embodiment:

The optical data of camera lens is as follows:

Face R d n

1 53.305 0.8 1.72

2 7.426 5.15

3 -20.927 0.7 1.62

4 9.523 0.52

5 10.825 2.97 1.85

6 60.516 (d6)

Diaphragm S ∞ (ds)

7 14.727 4.4 1.76

8 -31.062 0.12

9 9.219 2.38 1.60

10 -9.219 4.4 1.85

11 6.28 1.2

12 10.522 2.33 1.71

13 -12.145

Here, R represents the radius-of-curvature of corresponding minute surface, and d represents center thickness or the airspace of corresponding eyeglass, and n represents the refractive index of corresponding eyeglass, and d6 and ds are variable airspaces, and the variation range of d6 is 11.16-0.8, and the variation range of ds is 8.33-0.25.

The above is only two kinds of preferred implementations of the art of this patent, does not form the restriction to the art of this patent, and all any modification, replacements etc. of making on technical scheme basis described in this patent, within all should falling into the protection domain of this patent.

Claims (2)

1. a low cost dual waveband optical zoom lens, comprise front lens group Gn, the diaphragm of negative power and be disposed at the rear lens group Gp with positive light coke of front lens group Gn as side, utilize airspace between front lens group Gn and rear lens group Gp to change to realize the zoom of 2.8-10mm; Described front lens group Gn has negative power convex concave first lens L1, negative power double concave the second lens L2 and positive light coke convex concave the 3rd lens L3 that are arranged in order to image space order by object space, described rear lens group Gp has lenticular the 4th lens L4 of the positive light coke being arranged in order to image space order by object space, lenticular the 5th lens L5 of positive light coke, negative power double concave the 6th lens L6 and lenticular the 7th lens L7 of positive light coke, and the 5th described lens L5 and the 6th lens L6 are gummed assembly; Seven materials that lens adopt in this camera lens, all containing expensive lanthanide glass and Extra-low Dispersion glass.

2. low cost dual waveband optical zoom lens as claimed in claim 1, is characterised in that the focal length of its seven optical lenses used and the radius-of-curvature of refractive index and 14 faces thereof meet the following conditions respectively:

-14.5<f1<-12 1.68<n1<1.75 24<R1<65 6.5<R2<9

-12.4<f2<-10.4 1.61<n2<1.67 -23<R3<-18 9<R4<13

14.8<f3<17.5 1.8<n3<1.88 10<R5<16 60<|R6|

Diaphragm

16.8<f4<19.9 1.69<n4<1.75 12.5<R7<21 -55<R8<-28.5

6<f5<8 1.63<n5<1.7 7<R9<10 -9.5<R10<-6.5

-4.6<f6<-3.1 1.81<n6<1.87 -9.5<R11<-6.5 5.2<R12<7.3

7.7<f7<9.2 1.69<n7<1.74 8.5<R13<12.8 -16.2<R14<-10.5

Low cost dual waveband optical zoom lens as claimed in claim 1, is characterized in that: the focal distance f=2.8-10mm of optical system, and field angle 2W=137 °-40 °, relative aperture F=1.8, rear cut-off distance is greater than 6.55mm.

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