CN104749756A - Aspherical dual-waveband confocal zoom lianr - Google Patents

Abstract

The invention discloses an aspherical dual-waveband confocal zoom lianr, which sequentially comprises a front lens group with negative focal power, a diaphragm and a rear lens group with positive focal power from the object side to the image side, wherein the front lens group comprises a meniscus-shaped first lens with negative focal power, a biconcave second lens with negative focal power, and a meniscus-shaped third lens with positive focal power; the rear lens group comprises a biconvex fourth lens with positive focal power, a meniscus-shaped or biconcave fifth lens with negative focal power, a biconvex sixth lens with positive focal power, and a biconvex seventh lens with positive focal power; the second lens and the third lens are gluing components; and the fourth lens is an aspherical lens. Through changing air space between the front lens group and the rear lens group, focal length changes are realized; through reasonable design and using the aspherical lens to correct aberration, resolutions of the lianr in the visible light and infrared light wavebands under the condition of large relative aperture are higher than one million pixels; and the lianr contains seven pieces of lenses, the structure is compact, installation is easy, and the production cost can be effectively controlled.

Description

The confocal zoom lens of a kind of aspheric surface two waveband

Technical field

This patent belongs to field of optical, relates to a kind of Zoom optic lens, especially adopts the high resolving power of the aspherical lens day and night confocal zoom lens of two waveband.

Background technology

The day and night two waveband zoom lens of focal length section near 3.0-10mm is the most widely used product of current protection and monitor field.What is called is two waveband day and night, refers to camera lens by day by visible light wave range imaging, and night is by the imaging of near infrared light wave band, and two wave band imaging points confocal haply, after ensureing camera lens installation, the image at daytime and night can keep clear.Along with the manufacturing process of high resolving power sensing element is ripe year by year, high-definition camera is more and more universal, the optical performance requirements of market to such camera lens increases year by year, and the camera lens that can reach the above resolution of mega pixel under visible ray and infrared light could adapt to the demand of round-the-clock high-definition monitoring.

On the other hand, in order to production control cost, optical texture is compact, the simple product of assemble flow will be the developing direction in market.Adopting aspherical lens, the number of lenses that camera lens uses can be reduced, reduce camera lens volume, reduce production assembly cost, the image quality of camera lens can be improved again simultaneously, particularly when reaching compared with object lens of large relative aperture, making camera lens maintain high-resolution.

At present, visible light wave range can reach the Related product of the above high definition imaging of mega pixel on the market, usually will use eight to nine spheric glasses, and it can only reach the resolution of about 300,000 pixels at night infrared wave band, not yet reach comparatively ideal two waveband confocal imaging.Such as be numbered the Chinese patent of 200910112238.2, " dual waveband optical zoom lens " by name, focal length section is 2.8-10mm, and achieve the imaging of visible ray mega pixel high definition, but it adopts nine spheric glasses, production cost is higher.

If aspherical lens can be utilized to develop use eyeglass number less and day and night two waveband can the product of high definition imaging, will there is very practical marketable value.

Summary of the invention

The object of this patent is that a kind of optical mirror slip of design adds up to seven, zoom ratio more than 2.8 times, the Zoom optic lens that visible ray and near infrared imaging can be confocal.Further, the imaging resolution of designed camera lens visible light wave range and night infrared optical band by day, all exceedes mega pixel.In order to, relative aperture less at eyeglass sheet number meet above-mentioned technical indicator larger, this camera lens adopts a slice aspherical lens.This camera lens needs compact conformation, and it is convenient to assemble.

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

The confocal zoom lens of a kind of aspheric surface two waveband, comprise the front lens group Gn of negative power, diaphragm and be configured at the rear lens group Gp with positive light coke of front lens group Gn image side, utilize the airspace between front lens group Gn and rear lens group Gp to change the change realizing focal length.Further, the focusing to camera lens is completed by front lens group Gn movable on optical axis.

Described front lens group Gn has negative power falcate first lens, negative power double concave second lens and positive light coke falcate the 3rd lens be arranged in order to image space order by object space.First lens of negative power and the second lenses guarantee front lens group Gn has enough negative powers, to meet wide-angle side imaging.The second described lens and the 3rd lens are gummed assembly, serve the effect reducing aberration.

Described rear lens group Gp have be arranged in order to image space order by object space lenticular 4th lens of positive light coke, negative power bent moon or double concave the 5th lens, lenticular 6th lens of positive light coke and lenticular 7th lens of positive light coke.The 4th described lens are near diaphragm, have at least one side to be aspheric surface, all can cover this lens in a big way by the unified light beam of diaphragm, utilize the effect of Aspherical corrector spherical aberration with this, the system-wide spherical aberration of effective reduction, realizes the blur-free imaging under object lens of large relative aperture condition.

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

-13.5﹤f1﹤-11 1.68﹤n1﹤1.75 24﹤R1﹤47 6﹤R2﹤7.2

-13.5﹤f2﹤-11.6 1.49﹤n2﹤1.62 -19﹤R3﹤-15 9﹤R4﹤13.1

14.7﹤f3﹤16.9 1.8﹤n3﹤1.88 9﹤R5﹤13.1 32<R6<62

Diaphragm

7.9﹤f4﹤9.6 1.67﹤n4﹤1.75 5.9﹤R7﹤8.5 -200﹤R8﹤-16

-9﹤f5﹤-7 1.8﹤n5﹤1.88 |35|﹤R9﹤|500| 6.1﹤R10﹤8.6

9﹤f6﹤16 1.49﹤n6﹤1.69 7.8﹤R11﹤12.5 R12﹤-10

16﹤f7﹤45 1.49﹤n7﹤1.70 14﹤R13﹤50 |13|﹤R14

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

The major optical index of product: focal distance f=3.2-9.2mm, zoom ratio is 2.9 times, corresponding field angle 2W=137.7 °-41.8 °, relative aperture F=1.8.Be the wide-angle side of 3.2mm at focal length, rear cut-off distance is greater than 6.5mm.

At visible light wave range, the optical transfer function mtf value of the camera lens made according to such scheme each visual field in whole focal length section is all greater than 0.3 at 150lp/mm place, and corresponding to 1/2.7 cun of sensor, camera lens reaches the high definition resolution close to two mega pixels.For the infrared band of 850nm, the optical transfer function mtf value of camera lens each visual field in whole focal length section is all greater than 0.3 at 120lp/mm place, makes nighttime imaging also reach the resolution of mega pixel, achieves comparatively ideal confocal imaging.

Accompanying drawing explanation

Accompanying drawing 1 is the optical system schematic diagram of this patent when zoom wide-angle side (focal length 3.2mm).

Accompanying drawing 2 is this patent optical system schematic diagram when zoom telescope end (focal length 9.2mm).

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

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

Embodiment

A kind of aspheric surface shown in accompanying drawing 1 is the confocal zoom lens of two waveband day and night, is made up of the rear lens group Gp of the front lens group Gn of negative power, diaphragm and positive light coke, by changing the airspace of front lens group Gn and rear lens group Gp, realizes the change of focal length.More specifically, move rear lens group Gp along optical axis direction, play the effect of zoom, move front lens group Gn along optical axis direction, play the effect compensating image planes skew.When interval, two groups, front and back is maximum, lens focus is the shortest, is zoom wide-angle side; When two groups, front and back are close gradually, 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.Diaphragm is placed between front lens group Gn and rear lens group Gp, for controlling the logical light quantity of camera lens.

Near the 4th lens of diaphragm in described rear lens group Gp, its unified upper light beam covering each visual field all to greatest extent, is designed to aspheric surface, and is born larger focal power, thus effectively reduced system-wide spherical aberration.6th lens and the 7th lens, adopt low dispersion as far as possible, to reduce axial chromatic aberration, make visible ray and infrared light confocal, effectively promote the imaging resolution of infrared band.

Specific embodiment:

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

Rear lens group Gp have be arranged in order to image space order by object space the lenticular 4th lens L4 of positive light coke, negative power falcate the 5th lens L5, the lenticular 6th lens L6 of positive light coke and the lenticular 7th lens L7 of positive light coke, 4th lens L4 and the 5th lens L5 by spacer ring near assembling, 5th lens L5 and the 6th lens L6 directly near assembling, the 7th lens L7 and the 6th lens L6 by spacer ring near assembling.4th lens L4 is aspherical lens.

The optical data of camera lens is as follows:

Face R d n

1 35.22 1.01 1.72

2 6.82 6.0

3 -16.282 0.7 1.52

4 10.639 3.85 1.85

5 53.04 (d5)

Diaphragm S ∞ (ds)

7 6.75(aspheric surfaces) 3.55 1.69

8-88.898(aspheric surfaces) 0.2

9 321.709 2.22 1.84

10 7.09 0.12

11 8.59 2.55 1.50

12 -16.613 0.1

13 34.2 3.78 1.69

14 -78.302

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, d5 and ds is variable air interval, and the variation range of d5 is the variation range of 13.99-2.49, ds is 6.85-0.1.

Constant of the cone K and the asphericity coefficient of the 7th are respectively:

K=-0.4916，A= 2.226546E-004,B=1.458801E-005,C=-1.116792E-007,D= 3.702228E-008；

Constant of the cone K and the asphericity coefficient of the 8th are respectively:

K=-435.961，A=6.708587E-004,B=3.915203E-005,C=-2.043297E-006,D= 2.076191E-007；

The above is only a kind of preferred implementation of the art of this patent, does not form the restriction to the art of this patent, all make on technical scheme basis described in this patent any amendment, equivalent to replace, within the protection domain that all should fall into this patent.

Claims (3)

1. the confocal zoom lens of aspheric surface two waveband, comprise the front lens group Gn of negative power, diaphragm and be configured at the rear lens group Gp with positive light coke of front lens group Gn image side, utilize the airspace between front lens group Gn and rear lens group Gp to change the change realizing focal length; Described front lens group Gn comprises falcate the 3rd lens L3 of the falcate first lens L1 of negative power, the double concave second lens L2 of negative power and positive light coke, described rear lens group Gp comprises the lenticular 4th lens L4 of positive light coke, the bent moon of negative power or double concave the 5th lens L5, the lenticular 6th lens L6 of positive light coke and the lenticular 7th lens L7 of positive light coke, the second described lens L2 and the 3rd lens L3 for gummed assembly; The focal length of seven optical lenses in camera lens and the radius-of-curvature in refractive index and 14 faces thereof meet the following conditions respectively:

-13.5﹤f1﹤-11 1.68﹤n1﹤1.75 24﹤R1﹤47 6﹤R2﹤7.2

-13.5﹤f2﹤-11.6 1.49﹤n2﹤1.62 -19﹤R3﹤-15 9﹤R4﹤13.1

14.7﹤f3﹤16.9 1.8﹤n3﹤1.88 9﹤R5﹤13.1 32<R6<62

Diaphragm

7.9﹤f4﹤9.6 1.67﹤n4﹤1.75 5.9﹤R7﹤8.5 -200﹤R8﹤-16

-9﹤f5﹤-7 1.8﹤n5﹤1.88 |35|﹤R9﹤|500| 6.1﹤R10﹤8.6

9﹤f6﹤16 1.49﹤n6﹤1.69 7.8﹤R11﹤12.5 R12﹤-10

16﹤f7﹤45 1.49﹤n7﹤1.70 14﹤R13﹤50 |13|﹤R14。

2. the confocal zoom lens of aspheric surface two waveband according to claims 1, is characterized in that, two surfaces of the 4th lens L4 are aspheric surface.

3. the confocal zoom lens of aspheric surface two waveband according to claims 1, is characterized in that: the focal distance f=3.2-9.2mm of optical system, and field angle 2W=137.7 °-41.8 °, relative aperture F=1.8, rear cut-off distance is greater than 6.5mm.