CN105700105A - Laser focusing and coupling device - Google Patents

Abstract

The invention discloses a laser focusing and coupling device. The device comprises four lenses, wherein two lenses are fixed, and the other two lenses are driven by a stepping motor to independently adjust positions. According to data obtained by lens parameter calculation or actual measurement, position adjustment is performed on two of the four lenses, the size of focusing spots is adjustable and focusing distance is unchanged. The laser focusing and coupling device provided by the invention realizes adjustment of the size of laser focusing spots without changing focus point distance.

Description

A kind of laser focusing coupling device

Technical field

Patent of the present invention belongs to optics and laser technology field, particularly relates to a kind of laser focusing coupling device。

Background technology

Laser power can be focused within the specific limits by laser focusing coupling device, is widely used to the fields such as laser marking, laser weld, cut and optical fiber coupling。General laser focusing bonder adopts monolithic sphere or non-spherical lens, and nearly parallel light focusing is in lens focus position, target is processed or is coupled into optical fiber。Owing to this kind of mode focal length of lens is fixed, the spot size after therefore focusing on is for determining value。But in the industries such as processing, generally require focal beam spot size adjustable to meet various sizes of process requirements, it is therefore desirable to a kind of focal beam spot size can adjust at any time, the focusing coupling device that focal position is constant simultaneously。According to the transformation matrix method in geometric optics, light can be expressed as propagating as shown in Figure 1, is shown as with matrix table:

If light is at the input plane of optical system and coordinates matrix respectively X1 and X2 on output plane, then the matrix T meeting X2=TX1 relation is called ray transfer matrices, is a 2*2 rank matrix。If arbitrarily the light of the direction of propagation is at system axial transmission range L, then ray transfer matrices is:

Light transformation matrix after the lens that focal length is f is:

Here focal length of convex lens is just, Concave Mirrors Focus is negative。

When considering focusing, owing to geometric optics can not obtain focal beam spot size, it is necessary to introduce Principles of Wave Optics and carry out Gaussian beam focusing, as shown in Figure 2。The focal length of lens is f, and incident Gauss wavelength is λ, and beam waist is ω 0, lens is girdled the waist into ω ', and after focusing, spot size is ω 0 '。For the bigger situation of incident laser bore, it is possible to above-mentioned situation is simplified and calculates, weigh focal beam spot size by Airy disk radius:

R=1.22 λ f/d

Wherein d is incident laser bore d=2 ω 0。Therefore, it can by the mode of laser facula size before adjusting lens, focus point spot size is adjusted, simultaneously when launching spot bore is sufficiently large, it is constant that focus point distance lens distance maintains focal distance f。

Summary of the invention

The invention provides a kind of laser focusing coupling device, it is achieved laser focusing hot spot is realized size adjustment, do not change the laser focusing coupling device of focus point distance simultaneously。

It is an object of the invention to be achieved through the following technical solutions:

A kind of laser focusing coupling device, it is characterised in that: this device is made up of four lens, and wherein two panels is fixed, and two panels is driven by stepper motor and independently adjusts position。

Calculate according to lens parameter or the actual data measured, the two panels in described four lens is carried out position adjustment, it is thus achieved that the while that focal beam spot size being adjustable, focusing distance is constant。

Compared with prior art, the present invention at least has the advantage that

By the technical scheme of the invention described above, patent of the present invention is a kind of employing multi-disc lens combination, and stepper motor drives, it is achieved laser focusing hot spot realizes size adjustment, does not change the laser focusing coupling device of focus point distance simultaneously。Device adopts 4 lens compositions, and light and main shaft angle represent with θ, represent with r with main shaft distance。Wherein f1, f2 are that concavees lens constitute one group, regulate and control its equivalent focal length by changing distance L1 between the two, change the hot spot r3 size on f3 lens；F3 is convex lens, by adjusting L2 size, diverging light is collimated；F4 is condenser lens holding position constant (or finely tuning when focusing distance varies slightly)。By the adjustment of f1, f2 and f3, the spot size being incident on condenser lens f4 changes, so that operating position B (focal position) spot size changes。

Accompanying drawing explanation

Fig. 1 is the lens focus schematic diagram of the Gaussian beam in embodiment of the present invention laser focusing coupling device；

Fig. 2 is the relation schematic diagram of the focal beam spot size in embodiment of the present invention laser focusing coupling device and L1。

Detailed description of the invention

Below in conjunction with the accompanying drawing in the present invention, the technical scheme in the present invention is clearly and completely described, it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments。Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art obtain under not making creative work premise, broadly fall into the scope of protection of the invention。

As shown in Figure 1-2, for a kind of laser focusing coupling device that the embodiment of the present invention proposes, this device is made up of four lens, and wherein two panels is fixed, and two panels is driven by stepper motor and independently adjusts position。

Calculate according to lens parameter or the actual data measured, the two panels in four lens is carried out position adjustment, it is thus achieved that the while that focal beam spot size being adjustable, focusing distance is constant。

According to geometric optics, the light parameter on f1 face is:

R1=r0

Here owing to incident ray is nearly directional light, θ 0 ≈ 0。

Light parameter on f2 face is:

$r2=r1+\tan \left(\mathrm{\θ}1\right)L1=r1+\tan (-\frac{r1}{f1})L1$

Light parameter on f3 face is:

R3=r2+tan (θ 2) L2

θ 3=0

On B face, hot spot is sized to:

R4=r3

Here we choose one group of parameter in the cards, and the adjusting range of wavelength X=1064nm, r0=1mm, f1=-10mm, f2=-20mm, f3=100mm, f4=1m, L1 is 0-50mm, it is thus achieved that work surface on focal beam spot radius size be 7um-20um。This kind of spot size adjusts when being very suitable for carrying out Laser focus immediately, and the focal beam spot adjustment when coupling single mode or multimode fibre。

Concrete adjustment mode adopts lens barrel f2, f4 to be fixed, and f1, f3 adopt the relative lens barrel motion of sleeve sliding type。Stepper motor s1, s3 and lens barrel are fixed, and are connected respectively at f1, f3 by connecting rod, by automatically controlled flexible adjustment f1 and f3 relative position。When f1 position adjustment, according to calculating or measured data, adjust f3 position, it is ensured that diverging light is collimated by f3 simultaneously。

Compared with prior art, the present invention at least has the advantage that

By the technical scheme of the invention described above, patent of the present invention is a kind of employing multi-disc lens combination, and stepper motor drives, it is achieved laser focusing hot spot realizes size adjustment, does not change the laser focusing coupling device of focus point distance simultaneously。Device adopts 4 lens compositions, and light and main shaft angle represent with θ, represent with r with main shaft distance。Wherein f1, f2 are that concavees lens constitute one group, regulate and control its equivalent focal length by changing distance L1 between the two, change the hot spot r3 size on f3 lens；F3 is convex lens, by adjusting L2 size, diverging light is collimated；F4 is condenser lens holding position constant (or finely tuning when focusing distance varies slightly)。By the adjustment of f1, f2 and f3, the spot size being incident on condenser lens f4 changes, so that operating position B (focal position) spot size changes。

The above; being only the present invention preferably detailed description of the invention, but protection scope of the present invention is not limited thereto, any those familiar with the art is in the technical scope that the invention discloses; the change that can readily occur in or replacement, all should be encompassed within protection scope of the present invention。Therefore, protection scope of the present invention should be as the criterion with the protection domain of claims。

Claims (2)

1. a laser focusing coupling device, it is characterised in that: this device is made up of four lens, and wherein two panels is fixed, and two panels is driven by stepper motor and independently adjusts position。

2. laser focusing coupling device as claimed in claim 1, it is characterised in that: calculate according to lens parameter or the actual data measured, the two panels in described four lens is carried out position adjustment, it is thus achieved that the while that focal beam spot size being adjustable, focusing distance is constant。