JPH0313285A - Laser marking device - Google Patents

Abstract

PURPOSE:To execute the marking of a large area with one set of a transmitter by providing a deflector for deflecting a laser optical axis and a prism on the pulse laser beam incident side of a marking pattern mask. CONSTITUTION:A laser beam 2 outputted from a pulse laser transmitter 1 is expanded by beam shaping parts 3, 4, and also, shaped to long elliptical shape, and irradiates a deflector 6 by a reflecting mirror 5. From the deflector 6 to a prism 7, a first laser pulse P1 and a second laser pulse P2 are deflected at a swing angle 2thetaS and irradiates the prism 7. A mask 8 for forming a marking pattern is provided behind the prism 7, and the laser pulse which transmits through the mask 8 passes through a light shielding plate 11 and brought to image formation on the surface of an object 10 to be worked by an image forming optical system 9, respectively and marking is executed. In such a manner, even with the irradiation of plural pulse lasers, a laser irradiation area is not superposed on the surface to be worked, and the marking of a uniform contrast can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a marking device using a laser, and in particular,
The present invention relates to an optical system that realizes large-area marking in a mask-type laser marking device that uses a marking pattern mask.

[Conventional technology]

In a laser marking device that uses a mask for pattern formation, in order to mark a large area without using a high-output pulsed laser oscillator, the large mask is divided into multiple areas and the laser beam is applied to each area. A widely known method is the divisional marking method, which involves irradiating the area with irradiation.

As a means of moving and irradiating the mask with laser light,
A method in which the laser beam is first reflected by a reflecting mirror and irradiated onto the mask, and then the reflecting mirror is moved in parallel to irradiate the laser beam, thereby irradiating the mask with the laser beam whose initial laser optical axis has been moved in parallel; Alternatively, there is a method in which an optical fiber is used and the exit port is moved relative to the mask. In either case, large-diameter laser beams are simulated by irradiating multiple laser beams. Related devices of this type include, for example, Japanese Unexamined Patent Publication No. 63-84786, No. 62-27 of the same town.
No. 0293, No. 62-203] No. 17, and the like.

[Problem to be solved by the invention]

In the above conventional technology, when a marking pattern mask is irradiated with several m times of laser pulse light, the irradiation area on the same mask is completely divided, and each part of the marking pattern mask is irradiated multiple times for the same workpiece. No consideration was given to preventing laser irradiation. Therefore, on the surface to be processed.

This creates an area that is irradiated with multiple laser pulses.

There is a problem in that it is difficult to obtain markings with uniform contrast over the entire marking area of the workpiece.

Furthermore, when a liquid crystal mask is used as a marking pattern mask, in addition to the above problems, even when marking a single workpiece, the pulsed laser beam passes through the same area on the mask multiple times, so the liquid crystal The problem of accelerating the lifespan of mass consumers also arose.

An object of the present invention is to provide a laser marking device that realizes marking with uniform contrast even when a marking pattern mask is divided and a plurality of shots of laser pulse light are irradiated.

Another object of the present invention is to provide a laser marking device that extends the life of a liquid crystal mask when a liquid crystal mask is used.

[Means to solve the problem]

In order to achieve the above objective, the pulsed laser optical axis emitted from the pulsed laser oscillator is deflected at a certain swing angle for each pulse, and is irradiated across the apex of the prism. To obtain a plurality of parallel beams of pulsed laser beams without overlapping.

In order to achieve the other objectives mentioned above, the prism and the liquid crystal mask are separated so that the laser beam off the main laser optical axis, which travels almost perpendicularly to the liquid crystal mask after passing through the prism, does not hit the liquid crystal mask. This is what I did.

[Effect]

The direction of the laser optical axis output in pulses from one pulse laser oscillator is changed for each pulse laser beam by a deflector, and a part of the laser beam is alternately directed to both slopes of the prism. Irradiate across the vertices. The transmitted light of the prism enters the marking pattern mask almost perpendicularly.

It forms an optical axis toward the imaging optical system.

At this time, the laser light projected onto the other slope of the prism becomes a stray laser light deviated from the optical axis due to the action of the prism, and is separated from the laser light used for marking. As a result, a large diameter beam without overlapping of the respective laser beams can be realized using multiple shots of laser beams. Therefore, even if marking is done in multiple shots on the surface to be machined, the same part can be marked twice.
Marking with uniform contrast can be achieved without the need for repeated strikes.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. A laser beam 2 outputted in a pulsed manner from a pulsed laser oscillator 1 is expanded by a beam shaping section 3.4, shaped into an oblong shape, and irradiated onto a deflector 6 by a reflecting mirror 5. The second laser pulse P2 and the second laser pulse P2 are deflected by the deflector 6 to the prism 7 at a swing angle of 2θS, and the prism 7 is irradiated with the second laser pulse P2. A mask 8 for forming a marking pattern is provided after the prism 7, and the second
The laser pulse P2a and the second laser pulse PZa are imaged and marked on the surface of the workpiece 10 by the imaging optical system 9. Between the prism 7 and the imaging optical system 9, for example, a focusing lens, A front plate 11 was provided. As shown in FIG. 2, the marking of the workpiece 10 is performed by marking the number 12 with the second laser pulse P2s and by marking the number 12 with the second laser pulse Pzm.
Mark the number 34 with .

The prism 7 shown in this embodiment is a heptahedron having two slopes as shown in FIG. 3, and the prism angle shown in FIG.
F, where n is the prism refractive index at the wavelength of the laser beam 2, it is desirable to set it to satisfy n=5 in (θ5 + 7? p)/sin Op. At this time, the laser beam Pa irradiated beyond the vertex 0 of the prism 7 as shown by the dotted line in FIG.
If the beam deviates from the optical axis of 1 m, it will be absorbed by the tip plate 11.

As described above, according to the configuration of the present invention, when the elliptical first pulsed laser Pi passes through the prism 7, the diagonally shaded pulsed laser Po that deviates from the apex O and passes above, as shown in FIG. without irradiating the processed surface 10.
Irradiate 1. Therefore, the pulse laser P1 and the pulse laser PO do not overlap, and the pulse laser P1 is uniform.
1 irradiates the surface to be processed 10, a uniform marking can be made on the surface to be processed 10. This point will be further explained with reference to FIGS. 5 and 6 regarding the beam intensity of laser light during laser beam synthesis. The first loser pulse P1. deflected by the deflector 6. FIG. 5 (1) for each optical path of the second laser pulse P2
) (2) shows this again.

Laser light Pl is directed from the deflector 6 to the prism 7.

As shown in FIG. 6(1), the laser intensity distribution of P2 (cross section A-A) has a nearly trapezoidal distribution that decreases at the ends. The intensity distribution of the loser pulse after passing through the prism 7 (FIG. 5, cross section B-B) is as shown in FIG. becomes. In FIG. 5, the intensity distribution of the second laser pulse transmitted through the prism 7 on the cross section C-C is symmetrical to the distribution in FIG. 6(2). therefore,
The second laser pulse P1 and the second laser pulse P2 form a pseudo large-diameter beam on the mask, and the beam intensity is almost uniform with no overlapping of the laser beams, as shown in Figure 6 (3). distribution.

Further, the polarizer 12 may pass the pulse lasers Pi and P2 beyond the vertex O of the prism 7.

Since the polarizer 12 can have a large deflection angle and does not require accurate control, it is easy to manufacture.

According to this embodiment, the workpiece can be irradiated with laser light that does not overlap even if multiple shots of pulsed laser light are combined. In addition, by separating the prism and the imaging optical system, it is possible to deviate from the main optical axis.
This has the effect of preventing the workpiece from being irradiated with laser light that is not used for marking. Furthermore, since the light shielding plate stops receiving the laser light that deviates from the main optical axis, it is effective to prevent stray light within the laser marking device.

Another embodiment of the present invention will be described with reference to FIGS. 7 and 8. A deflector 12 and a prism 13 are added to the above embodiment, and the mask 8 is divided into four regions, and the laser beam 2 is deflected and irradiated onto each region. As a result, according to the six embodiments in which marking is performed in a 2×2 matrix as shown in FIG. 8, the marking area in a laser oscillator with the same output can be expanded.

Another embodiment of the present invention will be described with reference to FIGS. 9 and 10. Here, a linearly polarized pulsed laser is used as the laser oscillator 14, and a liquid crystal mask 15 is used as a marking pattern forming mask. The liquid crystal mask 15 is operated by a drive system 16 to control the polarization direction of the laser beam 2, and a polarization beam splitter 17 to control the polarization direction of the laser beam 2.
8 is separated from the optical path and directed toward the absorber 19.

By separating the prism 7 and the liquid crystal mask 15 by a distance of 0 or more as shown in FIG. 4, the laser beams deviating from the optical axis of the laser pulses P1m and P2m that pass through the prism 7 and head toward the imaging optical system 9 can be prevented. The liquid crystal mask 15 was prevented from being irradiated with the liquid crystal mask 15.

Control of the liquid crystal mask 15 will be explained using FIG. 10. The liquid crystal mask 15 is divided into two parts corresponding to the laser irradiation area, and when the laser is irradiated on the character "12" in the figure representing the mask information, the character 1134 T+ is prepared on the opposite side, and then the character When the laser is irradiated on the "34" side, the mask information on the character 141211 side is controlled to be rewritten.

According to this embodiment, since marking and rewriting of the contents of the liquid crystal mask can be performed at the same time, it is possible to perform large-area, high-speed marking with a variable-marking-content type laser marking device.

Furthermore, since the liquid crystal mask is not irradiated with the stray laser beam, it is effective in extending the life of the liquid crystal mask.

In the embodiment described above, an example is shown in which a galvano scan mirror is used as a deflector for deflecting laser light output from one laser oscillator at a certain swing angle of 20 seconds, but one point of the mirror is used as a fulcrum. Any device may be used as long as it can change the angle of the mirror surface, and a deflection effect by an acousto-optic element may be used.

[Effects of the Invention] According to the present invention, a large area can be marked with one oscillator without using a high-output pulse laser oscillator, which is economical.

In addition, since the laser irradiation area on the mask surface can be completely divided, the laser irradiation areas do not overlap on the surface to be processed even when irradiated with a plurality of pulsed lasers, and marking with uniform contrast can be obtained.

Furthermore, since the laser beam deviated from the optical axis can be received, stray light does not occur inside the device, which has a safety effect.

Devices using a liquid crystal mask have the effect of extending the life of the liquid crystal mask by preventing unnecessary laser light irradiation.

Furthermore, since the parallel movement of the laser beam irradiated almost perpendicularly to the mask can be achieved with a simple configuration of a deflector and a prism, there is also the effect that the functionality of existing laser marking devices can be easily improved.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a laser marking device which is an embodiment of the present invention, Fig. 2 is a plan view of the processed surface of Fig. 1, Fig. 3 is a perspective view showing the external appearance of the prism shown in Fig. Figure 4 is an explanatory diagram of optical path separation by the prism in Figure 1, Figure 5 (1), (
2) is an explanatory diagram of the optical path by the prism in Figure 4, and Figure 6 (1)
) or 3) are characteristic diagrams of laser beam intensity, FIGS. 7 and 9 are configuration diagrams of a laser marking device that is another embodiment of the present invention, and FIGS. 8 and 10 are diagrams of FIGS. 7 and 9. FIG. 9 is a plan view of the processed surface of FIG. 9; 1... Laser oscillator, 6, 12... Deflector, 7, 1
3... Prism, 8... Mask, 15... Liquid crystal massmer, 17... Polarizing beam splitter, θS... Deflector Fig. 1 Fig. 7 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] 1. In an apparatus that irradiates a marking pattern mask having marking information with a pulsed laser beam emitted from a pulsed laser oscillator and transfers the marking information to a workpiece surface by an imaging optical system, the marking pattern is A laser marking device includes a prism and a deflector that deflects a laser optical axis toward the pulsed laser light incident side of a mask. 2. In an apparatus that transfers information on a marking pattern mask onto a workpiece surface using pulsed laser light from a pulsed laser oscillator, a means for deflecting the pulsed laser light for each pulse and a means for changing the optical axis by the means are provided. A prism that converts the pulsed laser beams into parallel laser beams that can be applied to the same workpiece without overlapping each pulsed laser beam.
A laser marking device provided between the pulsed laser oscillator and the marking pattern mask. 3. The laser marking device according to claim 1 or 2, wherein the laser pulse light whose laser optical axis is changed for each laser pulse shot by the deflector is irradiated so as to straddle the apex of the prism. laser marking equipment. 4. In the laser marking device according to any one of claims 1 to 3, a liquid crystal mask is used as the marking pattern mask, and a deflection beam splitter is provided between the liquid crystal mask and the imaging optical system. Laser marking device installed. 5. In an apparatus that irradiates a marking pattern mask having marking information with a pulsed laser beam emitted from a pulsed laser oscillator and transfers the marking information to a workpiece surface using an imaging optical system, the pulsed laser beam is incident on the marking pattern mask. A polarizer and a prism for deflecting a laser optical axis are arranged on one side, and the other side is arranged from the apex of the prism to the pulsed laser optical axis that passes through the apex of the prism and one side and heads toward the imaging optical system. A laser marking device characterized in that the prism and the imaging optical system are separated by a distance at which the deviated pulsed laser light that passes through and deviates from the laser optical axis is incident on the imaging optical system. 6. The laser marking device according to claim 5, wherein a liquid crystal mask is used as the marking pattern mask. 7. In an apparatus that irradiates a marking pattern mask having marking information with a pulsed laser beam emitted from a pulsed laser oscillator and transfers the marking information to a workpiece surface using an imaging optical system, a deflector is provided on the incident side of the pattern mask. and a prism, a liquid crystal mask is used as the pattern mask, the liquid crystal mask has at least two marking information display sections, and the marking information displayed on one display section is irradiated with pulsed laser light. A laser marking device characterized in that marking information is displayed on the other display section at the same time. 8. In an apparatus that irradiates a marking pattern mask having marking information with a pulsed laser beam emitted from a pulsed laser oscillator and transfers the marking information to a workpiece surface by an imaging optical system, the pulsed laser beam is incident on the marking pattern mask. A polarizer and a prism for deflecting a laser optical axis are arranged on one side, and the other side is arranged from the apex of the prism to the pulsed laser optical axis that passes through the apex of the prism and one side and heads toward the imaging optical system. A laser marking device characterized by irradiating a light-shielding body disposed at a position away from the optical path of the pulsed laser beam with an deviated pulsed laser beam that passes through and deviates from the laser optical axis. 9. The laser marking device according to claim 8, wherein a liquid crystal mask is used as the marking pattern mask. 10. In an apparatus that irradiates a marking pattern mask having marking information with a pulsed laser beam emitted from a pulsed laser oscillator and transfers the marking information to a workpiece surface using an imaging optical system, the pulsed laser beam is incident on the marking pattern mask. A deflector for deflecting the laser optical axis and a prism are arranged on the side, and the deflection half angle θ_S of the laser pulse light in the deflector, the prism inclination angle θ_F, and the refractive index n of the prism material at the wavelength of the laser pulse light are A laser marking device characterized by using a prism where n: sin(θ_S+θ_F)/sin θ_F. 11. A laser marking device characterized in that a scanning mirror or an acousto-optic element is used as the deflector according to any one of claims 1 to 10.