CN203643677U - Aspherical dual-waveband confocal zoom lianr - Google Patents

Abstract

The utility model 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 optical, mechanical and electronic integration field, relates to a kind of Zoom optic lens, especially adopts the day and night confocal zoom lens of two waveband of high resolving power of aspherical lens.

Background technology

Near the day and night two waveband zoom lens of focal length section 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 that camera lens is by day by visible light wave range imaging, and night is by the imaging of near infrared light wave band, and confocal haply of two wave band imaging point, to guarantee that, after camera lens installation, it is clear that the image at daytime and night can keep.Along with the manufacturing process of high resolving power sensing element is ripe year by year, high-definition camera is more and more universal, market requires to increase year by year to the optical property of such camera lens, 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, for production control cost, optical texture compactness, the simple product of assemble flow are by the developing direction that is market.Adopt aspherical lens, can reduce the eyeglass quantity that camera lens uses, reduce camera lens volume, reduce production assembly cost, can improve again the image quality of camera lens simultaneously, particularly, in the situation that reaching compared with object lens of large relative aperture, make 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, conventionally will use eight to nine spheric glasses, and it can only reach the resolution of approximately 300,000 pixels at night infrared wave band, not yet reach comparatively ideal two waveband confocal imaging.For example be numbered 200910112238.2 Chinese patent, " dual waveband optical zoom lens " by name, focal length section is 2.8-10mm, realized the imaging of visible ray mega pixel high definition, but it adopts nine spheric glasses, production cost is higher.

If can utilize aspherical lens to develop to use eyeglass number product less and that day and night two waveband can 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, and zoom ratio exceedes 2.8 times, the Zoom optic lens that visible ray and near infrared imaging can be confocal.And designed camera lens is the imaging resolution of visible light wave range and night infrared optical band by day, all exceedes mega pixel.For, relative aperture less at eyeglass sheet number meet above-mentioned technical indicator in the situation that of 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 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 variation of focal length.Further, complete the focusing to camera lens by move forward and backward front lens group Gn on optical axis.

Described front lens group Gn has the negative power falcate first lens, negative power double concave the second lens and positive light coke falcate the 3rd lens that are arranged in order to image space order by object space.The first lens of negative power and the second lens have guaranteed that 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, have played the effect that reduces aberration.

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

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:

-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 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=3.2-9.2mm, zoom ratio is 2.9 times, corresponding field angle 2W=137.7 °-41.8 °, relative aperture F=1.8.The wide-angle side that is 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 of making 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 has reached the high definition resolution that approaches 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, has realized 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 embodiment of this patent spherical aberration, astigmatism, distortion curve figure in the time of zoom wide-angle side.

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

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 front lens group Gn, diaphragm and the positive light coke of negative power, by changing the airspace of front lens group Gn and rear lens group Gp, realizes the variation 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 of compensation image planes skew.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.Diaphragm is placed between front lens group Gn and rear lens group Gp, for controlling the logical light quantity of camera lens.

The 4th lens of close diaphragm in described rear lens group Gp, its unified upper light beam that all covers to greatest extent each visual field, is designed to aspheric surface, and bears larger focal power, thereby effectively reduces system-wide spherical aberration.The 6th lens and the 7th lens, adopt low dispersion as far as possible, to reduce axial chromatic aberration, makes visible ray and infrared light confocal, effectively promotes the imaging resolution of infrared band.

Specific embodiment:

Front lens group Gn has negative power falcate first lens L1, negative power double concave the 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 are by spacer ring near assembling, and the 3rd lens L3 and the second lens L2 glue together.

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, negative power falcate the 5th lens L5, lenticular the 6th lens L6 of positive light coke 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 be directly near assembling, the 7th lens L7 and the 6th lens L6 by spacer ring near assembling.The 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 surface) 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, and d5 and ds are variable airspaces, and the variation range of d5 is 13.99-2.49, and the variation range of 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 any modifications of making on technical scheme basis described in this patent, is equal to replacement etc., within all should falling into the protection domain of this patent.

Claims (2)

1. the confocal zoom lens of aspheric surface two waveband, 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 variation of focal length; Described front lens group Gn comprises falcate first lens L1, the double concave second lens L2 of negative power and falcate the 3rd lens L3 of positive light coke of negative power, described rear lens group Gp comprises lenticular the 4th lens L4 of positive light coke, bent moon or double concave the 5th lens L5, lenticular the 6th lens L6 of positive light coke and lenticular the 7th lens L7 of positive light coke of negative power, and the second described lens L2 and the 3rd lens L3 are gummed assembly; The radius-of-curvature of the focal length of seven optical lenses in camera lens and refractive index and 14 faces thereof meets 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

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

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

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