JPH0526596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laser processing device for processing patterns such as letters and figures on the surface of a workpiece.

[Technical background of the invention and its problems] Various methods have been developed in the past for processing specific patterns such as letters and figures on the surface of a workpiece. In one method, a mask made of a metal plate with a predetermined pattern punched out is placed on the workpiece, a laser beam is scanned from above the mask, and the laser beam that has passed through the mask is directed onto the workpiece surface. There are some types that process according to the pattern by irradiating it. However, in this case, it is necessary to bring the mask into close contact with the surface of the workpiece, so if the surface of the workpiece has irregularities, it is not possible to process a clear pattern.

In addition, a method has also been put into practical use in which a focused laser beam is irradiated onto a mask according to a predetermined program and the irradiated area is processed according to the pattern, but since the focused beam is scanned, large area processing is required. requires a long time.

Another method that has been put into practical use is to form a pattern on the surface of the workpiece by focusing the laser beam that has passed through the mask onto the workpiece using a condensing optical system. Since it is limited to corners, it is not possible to process large areas.

In this way, in the conventional technology, characters with a large number of digits,
The disadvantage was that it was not possible to mark numbers efficiently.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a laser processing device that can efficiently process large areas.

[Summary of the invention]

In this invention, a laser beam oscillated from a laser oscillator is scanned against a mask provided with a specific pattern to be processed into a workpiece by an optical system composed of a scanning optical system and an inverted imaging optical system. The present invention is configured to achieve the above object.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, a laser oscillator 1 is adapted to oscillate a laser beam 3 having an optical axis 2. In FIG. This laser beam 3 may be either a pulsed type or a CW oscillation light. A reflecting mirror 4 serving as a scanning optical system is tilted in the traveling direction of the laser beam 3 and fixed to a holder 5. The holder 5 also forms an inverted image of the laser beam 3 reflected from the reflecting mirror 4 on the surface of the workpiece 6, and forms patterns 7, such as letters and figures, on the workpiece 6.
In order to engrave the image, three reflecting mirrors 8, 9, 10 and a condensing lens 11 are provided, and these constitute an inversion imaging optical system P. A drive mechanism 12 is provided on the upper part of the holder 5 for moving the holder 5 in parallel with the laser beam 3 oscillated by the laser oscillator 1 as shown by arrow A. This drive mechanism 12 supports the left end of a feed guide screw 14 which is rotatable in forward and reverse directions by a bearing 15 and is driven by a motor 13 provided at the right end.
Nuts 16, 16 are screwed into the feed guide screw 14, and the nuts 16, 16 are fixed to the holder 5.

Laser beam 3 reflected by the reflecting mirror 4
A mask 17 is fixed to the main body of the apparatus (not shown) in the optical path perpendicular to the optical axis 2. The mask 17 is made of an opaque material, and has transparent portions 18 formed of through holes or transparent portions corresponding to the pattern engraved on the workpiece 6. The inverted imaging optical system is arranged so that the pattern formed by the transparent portions 18 of the mask 17 and the pattern 7 engraved on the workpiece 6 have an imaging magnification of 1:1. It is set up. In this embodiment, the condenser lens 11 is positioned midway between the optical path lengths of the mask 17 and the workpiece 6.

When the laser beam 3 is oscillated from the laser oscillator 1 in the laser processing apparatus configured as described above, the laser beam 3 is reflected by the reflecting mirror 4, passes through the transparent part 18 of the mask 17,
The light is symmetrically reversed by an odd number (three in the embodiment) of reflecting mirrors 8, 9 and 10, and then enters the condenser lens 11. The laser beam 3 emitted from the condenser lens 11 forms a real image of the mask 17 on the surface of the workpiece 6 at an image magnification of 1:1. Next, the holding body 5
When the is moved as shown by arrow A by rotating the motor 13, the reflecting mirror 4 as a scanning optical system and the reflecting mirrors 8, 9, as an inversion imaging optical system are moved.
10 and the condenser lens 11 are integrated with the holder 5 and moved horizontally as shown by the arrow A, and the laser beam 3 is irradiated to the transparent part 18 on the left side of the mask 17, and the image is projected onto the surface of the workpiece 6. to form an image,
Engraving a pattern. In this way, the reflecting mirrors 8, 9
Since the image of the mask 17 and the image formed on the surface of the workpiece 6 are opposite to each other in the scanning direction A, the images are reversed once symmetrically at 10 and 10, and then reversed again at the condenser lens 11. , the image on the workpiece 6 remains stationary even if the inverted imaging optical system is moved horizontally to the left, and the laser beam 3 is inverted only in the direction perpendicular to the plane of the paper. Only the portion that passes through the surface of the workpiece 6 is evaporated or melted and processed. When processing using the scanning method described above, the pattern 7 is processed on the workpiece 6 according to the transparent parts 18 formed on the mask 17, and the laser beam 3 does not irradiate the entire surface of the mask 17 at the same time. By irradiating portions one by one, a pattern can be engraved on the surface of the workpiece 6 using the mask 17 over a wide area. Also,
If the laser beam 3 is also scanned in a direction perpendicular to the direction of arrow A, that is, in a direction perpendicular to the paper surface, the workpiece will be processed by passing through the mask 17, which has a relatively wide area determined by the width of the laser beam 3 and the size of the scanning stroke. A pattern 7 can be processed on the surface of the object 6. Practically speaking, if marking is required in several lines and with many characters, such as product lot numbers or car body numbers, the cross-sectional area of the laser beam 3 should be only a few lines high. Even if it is, it is sufficient to scan in that direction.

Furthermore, if a laser beam 3 with a high peak output such as a CO ₂ laser is used as the laser, marking can be made in a rectangular area by using multiple pulses and uniformly irradiating the mask 17 while scanning. can.

Next, FIG. 2, in which the same components in FIG. 1 are given the same reference numerals, shows a second embodiment of the present invention,
A concave mirror 21 is used in place of the condensing lens 11, thereby reducing costs.

Further, FIG. 3, in which the same components in FIG. 1 are given the same reference numerals, shows a third embodiment of the present invention, in which the ratio of the size of the mask 17 to the size of the pattern 7 of the workpiece 6 is 1:1. It is not set to 1, but is changed.
The reflecting mirror 10 and the condensing lens 11 are eliminated from the inversion imaging optical system P, and a concave mirror 22 is provided in their place. Further, the mask 17 and the workpiece 6 are scanned by motors 22 and 23, respectively, parallel to and synchronously with the laser beam 3 emitted from the laser oscillator 1. The pattern is reduced and projected onto the surface of the workpiece 6, and the scanning speed of the mask 17 and the workpiece 6 is set according to the magnification ratio. In other words, the speed of the mask 17 is
v ₁ , the speed of the workpiece 6 is v ₂ , and the magnification ratio is 1/M, then v 1 , v ₂ as v ₁ :v ₂ =M: ₁
All you have to do is set . Also, to enlarge by M times,
It is sufficient to set v ₁ and v ₂ so that v ₁ :v ₂ =1:M.

〔Effect of the invention〕

As explained above, in this invention, a scanning optical system and an inversion imaging optical system are used to inscribe patterns such as numbers and letters on the surface of a workpiece, and the imaging is inverted and scanned. Therefore, even if the diameter of the laser beam is small, it is possible to process a large-area processing pattern on the workpiece, and the effect is that it can be applied to laser processing such as marking and engraving. be.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing one embodiment of the invention, FIG. 2 is a longitudinal side view showing a second embodiment of the invention, and FIG. 3 is a third embodiment of the invention. FIG. DESCRIPTION OF SYMBOLS 1...Laser oscillator, 2...Optical axis, 3...Laser beam, 4...Reflector (scanning optical system), 5...Holder,
6... Workpiece, 7... Pattern, P... Inversion imaging optical system, 12... Drive device.

Claims (1)

[Scope of Claims] 1. A laser oscillator, a mask provided in the optical path of a laser beam emitted from the laser oscillator and having a pattern engraved on a workpiece on the beam incidence side, and a pattern of this mask. a scanning optical system that scans the laser beam through the scanning optical system; an inversion imaging optical system that inverts and forms a pattern image scanned by this scanning optical system with respect to the optical axis; A laser processing device comprising a holder that holds an optical system and a drive mechanism that moves the holder along the processing surface of the workpiece. 2. The laser processing apparatus according to claim 1, wherein the inversion imaging optical system and the scanning optical system are integrated to scan in the inversion direction of the inversion imaging optical system. 3. The laser processing apparatus according to claim 1, wherein the inversion imaging optical system comprises an odd number of reflecting mirrors including lenses or concave mirrors. 4. The laser processing apparatus according to claim 1, wherein the mask and the workpiece are scanned in synchronization with the image reversal direction at a scanning speed corresponding to the imaging magnification.