JPH0347685A - Method and device for laser beam marking - Google Patents

Abstract

PURPOSE:To carry out multi-series markings at the same time by splitting a laser beam into >= two and marking respective laser beams on marking areas. CONSTITUTION:One at least or more half mirrors 2 and one total reflection mirror 3 are arranged on a laser beam 9 optical axis and the laser beam 9 is split into >= two. The respective laser beams 9a and 9b are scanned by optical scanners 4 and 5, and condenser lens systems 11a, 12a, 13a; 11b, 12b and 13b and marked on the respective marking areas 8. By this method, the multi-series markings can be carried out at the same time on plural objects on the same plane.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a laser marking method and apparatus for marking an object by scanning a laser beam, and more specifically, a laser marking method and apparatus that can quickly mark an object on the same plane. Regarding equipment.

(Prior Art) As a conventional laser marking device, the device shown in FIG. 7 is known. In the same figure, 50 is Nd''-containing Y
The laser oscillator body has a built-in arc lamp 51b connected to the AG crystal lot 51a and the power source 51c, 52 is a rear mirror, 53 is a front mirror 54 is a 1le-Ne laser, and the above rear mirror 52 and front mirror 5
Laser oscillation is performed between 3 and continuous wave Nd:YA
G laser light is obtained.

Reference numeral 55 is a lens called an fθ lens, which focuses the laser beam and increases the power density since the output (power) of the YAG laser beam is weak and cannot be processed by laser beam.

Reference numeral 56 is an X-axis optical scanner, and 57 is a Y-axis optical scanner, which scans a laser beam in the X and Y directions to enable free one-stroke writing. In addition, 58.59
are reflective mirrors attached to each scanner 56, 57. 60 is the continuously emitted laser beam
N-OFFt, is a Q-3W element (electro-optical shutter) that allows characters, etc. to be cut off in the middle.

In addition, 61 is an object for laser processing, and 6
2 is a marking, and 63 is a controller.

(Problems to be Solved by the Invention) However, the conventional marking device described above has drawbacks such as slow marking speed (approximately 25 characters/5ec) and narrow printing range (marking area) (approximately 120φ).

As a technique for solving this drawback, a laser marking device shown in FIG. 8 is described in Japanese Patent Laid-Open No. 62-61788. That is, this laser marking device has a mirror 63 that semi-transmits and semi-reflects the laser and a mirror 64 that totally reflects the laser, and scans on the laser optical axis in front of these two mirrors 63 and 64 (on the laser oscillator side). A lens 55 is arranged.

According to the laser marking device shown in FIG. 8, by dividing the laser into two parts, it is possible to mark two places at the same time, which has the advantage of increasing the marking speed, but it also has the following drawbacks.

That is, the laser beam emitted from the scanner passes through the fθ lens 55, and is focused on the processing surface A when there is no mirror.

This surface is a light condensing surface located at a focal distance f from the position of the main surface of the fO lens. When the mirror 63 is provided on the optical axis, the light is focused on the position of the processing surface B. This distance is f, +f, =
There is a relationship of f. Furthermore, if the mirror 64 is provided on the optical axis,
The light is focused on the position of the processed surface C. The distance at this time is f +'+
There is a relationship f2'=f.

Therefore, the position of the processed surface is different between the position of the processed surface B by the mirror 63 and the position of the processed surface C by the mirror 64. This is because f+'>f, fz>f2'. For this reason, the conventional method has a disadvantage in that it is not possible to mark multiple objects on the same plane.

Therefore, an object of the present invention is to provide a laser marking method and apparatus that can simultaneously mark multiple objects on the same plane in multiple series.

[Means to solve the problem]

A laser marking method according to the present invention that achieves the above object divides the laser beam onto a tool by arranging at least one half mirror and one total reflection mirror on the laser optical axis, and separates each laser beam onto the tool. In the method of marking each marking area by scanning with an optical scanner, a condensing lens, and a lens system, the marking area is scanned by an optical scanner, a condensing lens, and a lens system, and the marking area is scanned by an optical scanner, a condensing lens, and a lens system. It is characterized by arranging a condensing lens system and marking a marking area on the same plane.

Further, the laser marking device according to the present invention divides the laser beam onto the tool by arranging at least one half mirror and one total reflection mirror on the laser optical axis, and transmits each laser beam to an optical scanner. In a laser marking device configured to mark each marking area by scanning with a condensing lens system, each marking is placed on each laser optical axis between the marking area and the half mirror and total reflection mirror. Particularly, in the above device, the two series of condensing lens systems are composed of a combination of a plurality of circular lenses, and Each lens is paired with a lens of another series, and is characterized in that each of at least one pair of circular lenses of the several pairs of circular lenses has a cutout surface, and the cutout surfaces are disposed in contact with each other.

In the present invention, a solid-state laser such as a Nd:l+-containing YAG laser is used as the laser, and the present invention functions effectively when a laser whose output is not so high is used.

(Function) Since the condensing lens for laser scanning used in the present invention is provided on the laser optical axis between the mirror and the marking target, the marking area can be made on the same plane.
For example, a large number of articles on a belt conveyor can be marked simultaneously in multiple series.

Note that by overlapping the marking areas or by cutting out and joining the lens system, it is possible to enlarge the marking area while maintaining the light condensing property without increasing the cost. In order to facilitate understanding of this, the relationship between lens diameter and light condensing characteristics will be explained based on FIG. 7. Normally, as shown in the figure, if the effective diameter of the lens is B and the diameter of the marking area is A, then A<B. If you want to make A larger, either increase f to increase the distance to the marking surface, or
It is conceivable to design the θ lens so that it is located as far outside as possible (imaging point a→a'). However, all of these deteriorate the beam focusing characteristics. In other words, a beam close to the optical axis is a problem or a small problem, and if it deviates from the optical axis, the beam becomes larger (the energy decreases accordingly).
I can no longer mark freely.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, ▪ is a condensing lens system, 2 is a half mirror, and 13 is a total reflection mirror. 4 is an X-axis optical scanner, 5 is a Yi@II optical scanner, 6
is a reflective mirror. 7 is an object to be marked, and 8 is a marking area.

The condensing lens system l used in the present invention can be configured by a lens fixing mechanism 10 to include a three-piece set of condensing lenses lla, 12a, 13a and paired condensing lenses llb, 12b, 13b, or a two-series laser beam. It forms a structure arranged on the optical axis. The lens has a cutout surface 14 in a portion thereof.

The lenses 12a and 12b, and 13a and 13b are arranged so that their respective notch surfaces 14 touch or are close to each other, for example, in contact with each other. After the cutout surfaces 14 are attached, they may be bonded by any means.

The notch ratio of the lens is preferably 5 to 20% (relative to the lens aperture). This makes it possible to prevent the marking from missing in the central portion between the lenses (the portion located at 80 in FIG. 9).

The lenses may be of various types depending on the characteristics of use, or may have a structure of 3 to 8 pairs, and in this embodiment, a structure of 3 pairs is used.

The lens diameter increases from the incident side to the exit side. Therefore, it is not necessary that all of them have a diameter of 120φ or more.

A method of marking using the above device will be described below.

For example, a laser beam 9 oscillated by a laser oscillator is divided into two by a half mirror 2 and a total reflection mirror 3. The divided laser beams 9a and 9b are condensed through a reflection mirror 6 and a lens system 1, and are marked in a marking area 8 on the same plane.

The marking area 8 has a shape as shown in FIG. 2, and has an overlapping portion 8a formed in the center, and this overlapping portion 8a corresponds to the notch surface 14 side of the lens system.

By forming such an overlapping portion 8a, as shown in FIG.
→ Mark in the order of 2 → 3 → ... 8, and at the same time mark with another series of lasers, for example 1' → 2' → 3' → ... 8'
You can mark in this order. Tatami center A-A
It is better not to place items on the lines.

In the present invention, it is possible to mark articles conveyed on the belt (stopped during marking). Examples are shown in FIGS. 4 and 5.

FIG. 4 shows a case where the marking area 8 is arranged perpendicular to the belt when the belt width is wide and the articles are conveyed widely. Further, FIG. 5 shows a case where the marking area 8 is arranged parallel to the belt when the belt width is relatively narrow and the article is conveyed with a narrow width.

Note that FIG. 6 shows the state of movement of the marking surface of the laser beam, and the laser beam is moved in the direction of the arrow by operating the obtacle scanner 4.5.

Furthermore, in the above embodiments, the case where the marking areas are overlapped by a notch in the lens system has been explained, but the invention is not limited to this, and it is also possible to provide an overlap without cutting out the lens system at all, or to overlap the marking area without cutting out the lens system. It is not necessary to provide For example, FIG. 9 shows an example in which marking areas 8 are matched. Whether the protruding portion 80 is slightly protruding or not can be solved by arranging the jig.

In the above embodiment, the case where the laser beam is divided into two is described, but the laser beam may be divided into three or more. Alternatively, the controllers 63 may be provided in the number of divisions to perform independent marking.

〔Effect of the invention〕

According to the present invention, it is possible to provide a laser marking method and apparatus that can simultaneously mark multiple objects on the same plane in multiple series.

[Brief explanation of drawings]

Fig. 1 is an explanatory cross-sectional view of main parts showing one embodiment of the present invention;
The figure is an explanatory diagram showing an example of the marking area same as above,
Figures 5 to 5 are diagrams showing the marking state, Figure 6 is an explanatory diagram showing the movement of the beam, Figures 7 and 8 are explanatory diagrams showing the conventional example, and Figure 9 is a diagram showing the state where the marking areas are matched. FIG. l: Condensing lens system 2: Half mirror 3: Total reflection mirror 4: X-axis optical scanner 5: Y-axis optical scanner 6/reflection mirror 7° Object to be marked 8: Marking area 9: Laser beam

Claims (1)

[Claims] 1. At least one half mirror and one total reflection mirror are arranged on the laser optical axis to split the laser beam into two or more, and each laser beam is focused by an optical scanner. In the method of marking each marking area by scanning with a lens system, the condensing lens system is arranged on each laser optical axis between the marking area and the half mirror and the total reflection mirror, A laser marking method characterized by marking a marking area on the same plane. 2. At least one half mirror and one total reflection mirror are arranged on the laser optical axis to split the laser beam into two or more, and each laser beam is scanned by an optical scanner and a condensing lens system. In a laser marking device configured to mark each marking area,
A laser marking device characterized in that the condensing lens system that makes each marking area on the same plane is disposed on each laser optical axis between the marking area and the half mirror and total reflection mirror. . 3. The condensing lens system of the second series consists of a combination of a plurality of circular lenses, each of the condensing lens systems forming a pair with a lens of another series, and at least one pair of circular lenses of the pair of circular lenses. 3. The laser marking device according to claim 2, wherein each of said notch surfaces are disposed in contact with each other.