CN101211002A - Laser zooming expander lens and regulating method - Google Patents

Abstract

The invention discloses a laser zoom expander and an adjustment method. The lens comprises three lenses in sequence, in which the focal power of a first lens is plus, that of the second lens is minus and that of the third lens is plus. The Focal power of each lens are respectively expressed as f1, f2 and f3. Distribution of the focal power of each lens shall meet: 0.25<f1/f3<0.3, -0.1<f2/f3<-0.05. The combined focal length of f12=f1+f2-d1*f1*f2 is obtained by changing the distance d1 between f1 and f2, obtain; then, f12 and f3 are confocal to produce certain zooms of extender output with the zoom being n<x>=f3/f12 by adjusting the distance d2 between the former two lens sets and the lens set f3. The f12 and f3 are confocal to obtain different zooms of extender outputs by changing d1 to obtain different f12. With the zoom expander, the invention obtains large opening angle of image space in the laser zoom system and improve the energy density at the focus at laser focusing so as to improve the laser processing effect and efficiency.

Description

Laser zooming expander lens and control method

[technical field]

The present invention relates to a kind of laser applied optics camera lens, particularly relate to a kind of laser beam zooming expander lens and control method thereof.

[technical background]

In the laser processing procedure, require laser very concentrated usually, guarantee the energy density of laser processing procedure focus point, make laser work effectively, and improve the work efficiency of laser at the energy of focus point.Use same laser instrument, how when work, to improve the focus energy density of laser? an answer is to obtain as far as possible little focus point.According to the diffraction limit theory: the angle of divergence θ of laser and waist diameter d ₀The pass be $\mathrm{\&theta;}\&CenterDot;d_0=\frac{4\mathrm{\&lambda;}}{\mathrm{\&pi;}},$ Wherein for using certain laser instrument, Wavelength of Laser λ is certain, so, the angle of divergence θ of laser and waist diameter d ₀Product be constant.Generally less from the laser beam diameter of laser instrument output, before the convergence optical system by certain focal length focuses on, require the expanded light beam diameter to reduce angle of divergence θ, obtain bigger incident beam diameter simultaneously.Suppose to add a laser beam expanding system in laser instrument and focal length are the convergence optical system of f, select suitable expansion bundle multiple β as requested for use, making laser beam enlarge to diameter is D=β d ₀, this moment laser angle of divergence θ _λStill satisfy the diffraction limit theoretical relationship ${\mathrm{\&theta;}}_{\mathrm{\&lambda;}}\&CenterDot;D=\mathrm{\&theta;}\&CenterDot;d_0=\frac{4\mathrm{\&lambda;}}{\mathrm{\&pi;}},$ So, ${\mathrm{\&theta;}}_{\mathrm{\&lambda;}}=\frac{\mathrm{\&theta;}}{\mathrm{\&beta;}}=\frac{4\mathrm{\&lambda;}}{\mathrm{\&pi;D}}.$ Like this, desirable convergent laser hot spot $\mathrm{\&delta;}={\mathrm{\&theta;}}_{\mathrm{\&lambda;}}\&CenterDot;f=\frac{4\mathrm{\&lambda;}\&CenterDot;f}{\mathrm{\&pi;D}}.$ So, obtain suitable D value by selecting suitable multiple β for use, just can obtain desirable focal beam spot δ to improve the energy density at job spotlight place.In actual applications, often use with a kind of Focused Optical system, generally it all has requirement to the incident beam diameter, but we often use different laser instruments, and the laser beam size of every kind of laser instrument output has difference.Like this, use the laser beam expanding system of specific factor just can't reach best effect.

[summary of the invention]

The technical matters that institute of the present invention desire solves provide a kind of can be at any time as required laser beam enlarging bundle multiple become laser optical lens doubly flexibly.

Another technical matters that institute of the present invention desire solves provides a kind of control method of zooming expander lens.

For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of laser zooming expander lens comprises that focal length is respectively f ₁, f ₂, f ₃Three groups of lens, described three groups of lens are made of single lens respectively, totally three lens, described three lens are arranged in order, wherein first power of lens is being for just, and first lens are that protruding flat pattern positive lens, second lens are that platycelous or double concave type negative lens, the 3rd lens are the planoconvex positive lens.

Described laser zooming expander lens, each power of lens ratio meets following requirement:

0.25＜f ₁/f ₃＜0.3

-0.1＜f ₂/f ₃＜-0.05

Wherein, f ₁Be first power of lens, f ₂Be second power of lens, f ₃It is the 3rd power of lens.

A kind of method of regulating laser zooming expander lens, described method is by changing lens combination f ₁, f ₂Between apart from d ₁, obtain the combined focal length f of different preceding two lens combination ₁₂=f ₁+ f ₂-d ₁F ₁F ₂Then, by regulating preceding two lens combination and lens combination f ₃Between apart from d ₂, make f ₁₂With f ₃Confocal and the expansion bundle output that produces certain multiple, expanding the bundle multiple is n ^x=f ₃/ f ₁₂By changing d ₁Obtain different f ₁₂, regulate d again ₂Make f ₁₂With f ₃Confocal, just can obtain the light beam output of different expansion bundle multiples.

The beneficial effect that the present invention can reach is: utilize this Zooming expander, can make laser focusing system obtain bigger picture side's aperture angle, and the energy density at focus place when greatly improving laser focusing, and improve the working (machining) efficiency of laser; And, because the expansion bundle multiple of laser beam can regulate at any time, can use at the different laser parameters of various lasers output with a kind of optical application system and process; The laser output parameter that also can be used for simultaneously same type is applied to different laser applied optics systems has different requirements to the laser input parameter.According to the diffraction limit theory

Owing to increased beam diameter d when expanding bundle, make that the laser beam divergence θ behind the expansion bundle correspondingly reduces, improve the focusing power of laser focusing system widely.

[description of drawings]

The invention will be further described in conjunction with the embodiments with reference to the accompanying drawings.

Fig. 1 is the schematic diagram of camera lens of the prior art.

Fig. 2 is a structural representation of the present invention.

[embodiment]

Consult Fig. 1 and Fig. 2, this laser beam expanding camera lens comprises three groups of lens, is respectively f by focal length ₁, f ₂, f ₃Three groups of lens combination constitute, according to preferred embodiment of the present invention, lens L1 of the present invention is that protruding flat pattern positive lens, lens L2 are platycelous or double concave type negative lens, lens L3 is the planoconvex positive lens, wherein first lens strength is for just, second lens strength is for negative, and the 3rd lens strength is for just.First lens and second combination of lenses constitute focal power and are negative front lens group, and front lens group and the 3rd lens are confocal to constitute the Galileo telescope system architecture by regulating, and concerns below the focal length of each lens satisfies:

0.25＜f ₁/f ₃＜0.3，-0.1＜f ₂/f ₃＜-0.05。

For making those of ordinary skill in the art can more be expressly understood technology contents of the present invention, specified especially exemplified by preferred embodiment of the present invention.

See also Fig. 2, system is made of L1, L2, three lens of L3, and L1 is that two curved surface S1, the S2 of R1, R2 constitute by radius-of-curvature respectively, its center thickness d 1, and material is Nd1: Vd1; L2 is that two curved surface S3, the S4 of R3, R4 constitute by radius-of-curvature respectively, its center thickness d 3, and material is Nd3: Vd3; L3 is that two curved surface S5, the S6 of R5, R6 constitute by radius-of-curvature respectively, its center thickness d 5, and material is Nd5: Vd5; Lens L1 and lens L2 are spaced apart d2, and lens L2 and lens L3 are spaced apart d4, and this two parameter is regulated according to expanding bundle multiple difference.

Embodiment 1

Applicable wavelengths: λ=1064nm

Become times scope: 2 ^x-8 ^xMaximum output beam diameter is: φ 30mm

f ₁/f ₃＝0.26 f ₂/f ₃＝-0.07

Curved surface S	Curvature R	Face is d at interval	Material Nd/Vd
				1	30.83	3	1.8/25.4
2	0	d2
				3	-8.99	2	1.46/68
4	10.45	d4
				5	0	3	1.8/25.4
6	-118.3

The relation that wherein expands between between bundle multiple and lens and interval d2, the d4 is as follows:

Multiple n x	Interval d2	Interval d4
			2 x	21.72	120.15
3 x	19.01	126.79
			4 x	16.30	130.12
5 x	13.59	132.12
			6 x	10.88	133.45
7 x	8.17	134.40
			8 x	5.46	135.11

Embodiment 2

Applicable wavelengths: λ=266nm

Become times scope: 2 ^x-8 ^xMaximum output beam diameter is: φ 30mm

f ₁/f ₃＝0.28 f ₂/f ₃＝-0.07

Curved surface S	Curvature R	Face is d at interval	Material Nd/Vd
				1	20.7	3	1.46/68
2	0	d2
				3	0	2	1.46/68
4	5.297	d4
				5	0	4	1.46/68
6	-73.11

The relation that wherein expands between between bundle multiple and lens and interval d2, the d4 is as follows:

Multiple n x	Interval d2	Interval d4
			2 x	24.08	126.99
3 x	20.75	133.91
			4 x	17.43	137.37
5 x	14.09	139.45
			6 x	10.76	140.84
7 x	7.44	141.82
			8 x	4.11	142.56

According to the foregoing description, monotropic times of scope is 2 ^x-8 ^xBetween, the fixed diameter of incident beam, so as can be seen, along with the expansion of multiple, d2 makes and is constantly reducing at interval, and d4 constantly increases at interval, and the f among two embodiment ₁/ f ₃With f ₂/ f ₃Ratio be respectively 0.26 ,-0.07 and 0.28 ,-0.07, so in the design expander lens, regulate d2 and d4 according to the needs that expand bundle and can realize becoming and doubly expand the purpose of restrainting, regulate simple and convenient.

Claims (3)

1. a laser zooming expander lens comprises that focal length is respectively f ₁, f ₂, f ₃Three groups of lens, it is characterized in that: three groups of lens are made of single lens respectively, totally three lens, described three lens are arranged in order, wherein first power of lens is being for just, and first lens are that protruding flat pattern positive lens, second lens are that platycelous or double concave type negative lens, the 3rd lens are the planoconvex positive lens.

2. laser zooming expander lens as claimed in claim 1, each power of lens ratio meets following requirement:

0.25＜f ₁/f ₃＜0.3

-0.1＜f ₂/f ₃＜-0.05

Wherein, f ₁Be first power of lens, f ₂Be second power of lens, f ₃It is the 3rd power of lens.

3. a method of regulating laser zooming expander lens is characterized in that: by changing lens combination f ₁, f ₂Between apart from d ₁, obtain the combined focal length f of different preceding two lens combination ₁₂=f ₁+ f ₂-d ₁F ₁F ₂Then, by regulating preceding two lens combination and lens combination f ₃Between apart from d ₂, make f ₁₂With f ₃Confocal and the expansion bundle output that produces certain multiple, expanding the bundle multiple is n ^x=f ₃/ f ₁₂By changing d ₁Obtain different f ₁₂, regulate d again ₂Make f ₁₂With f ₃Confocal, just can obtain the light beam output of different expansion bundle multiples.

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