JP2002103076A - Device and method of laser marking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-cost laser marking device that has a simple structure and ensures high productivity and also to obtain its method. SOLUTION: The laser marking device consists of a laser light source 1 which emits a laser beam to the surface of a workpiece 5, and a scanning means for the laser beam. The diameter of the laser projection spot 6 is larger than the machining line width or machining spot diameter 7 on the surface of the workpiece. As a heating means for heating the workpiece, a preheating laser light source can be used which is separate from the machining laser light source. The laser marking method is such that the laser beam is scanned by the scanning means to form a character, graphic or symbols, and that the machining line width or spot diameter produced on the workpiece by the laser beam exposure is controlled by adjusting the irradiating output or time with the laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of characters, numbers, barcodes or two-dimensional codes having information such as date and serial number on industrial parts such as electronic parts such as ICs, glass substrates of liquid crystal or PDP panels. The present invention relates to a marking device for marking and a marking method.

[0002]

2. Description of the Related Art Conventionally, a marking device has been configured as shown in FIG. In FIG. 10, 1 is a laser light source,
Reference numerals 2 and 3 denote scanner mirrors, 4 denotes a condenser lens, and 5 denotes a workpiece. Next, an operation for marking a two-dimensional code on the workpiece 5 using the marking device of FIG. 10 will be described. First, the scanner mirrors 2 and 3 rotate. After the positioning of the scanner mirrors 2 and 3,
Scanner mirrors 2 and 3 stop. When a laser beam 8 is irradiated from the laser light source 1, the laser beam irradiation spot 6 on the workpiece 5 undergoes a physical change (for example, peeling, vaporization, burning, foaming, bulging, discoloration / discoloration, etc. of the surface or surface layer). By raising, the processing spot 7 is formed and becomes the first segment. Thereafter, the above operation is repeated until the final segment is formed, thereby forming a two-dimensional code. In the apparatus and method as described above, for example, I
A bar code or a two-dimensional code having information such as a date and a serial number is marked on an electronic component such as C, a liquid crystal or an industrial product such as a glass substrate of a PDP panel.

[0003]

However, in the conventional marking apparatus, in order to change the width of the processing line or the size of the processing spot, the distance from the condensing lens to the workpiece is mechanically adjusted or the marking is performed. It was necessary to change the size of the stop diameter by placing a stop in the apparatus, and to change the laser irradiation area irradiated on the workpiece. Therefore, an adjusting mechanism or a diaphragm for adjusting the distance from the condensing lens to the workpiece is required, and there has been a problem that the apparatus configuration is complicated and the apparatus cost is increased. Further, in the conventional marking device, the workpiece is physically changed (for example, peeling of a surface or a surface layer, vaporization, burning, foaming, bulging, discoloration,
It is necessary to continuously irradiate the laser beam until the occurrence of bleaching or the like, so that the irradiation time is long. That is, there is a problem that the marking time is long and the productivity is low. Accordingly, it is an object of the present invention to provide a laser marking device having a simple configuration, a low device cost, and high productivity, and a method therefor.

[0004]

In order to solve the above-mentioned problems, a marking apparatus according to the present invention is a marking apparatus comprising at least a laser light source 1 for emitting laser light and scanning means 2 and 3 for scanning the laser light. The laser beam is applied to the workpiece 5 so that the irradiation spot 6 is equal to or larger than the processing line width on the workpiece 5 or the processing spot 7. In the above marking apparatus, the marking method according to the present invention is a marking method in which a laser beam emitted from a laser light source 1 is scanned by scanning means 2 and 3 to form a character, a figure or a symbol on a workpiece 5. Workpiece 5 by adjusting output
This is a method of controlling the processing line width or the processing spot 7 generated in the above. Normally, the intensity of the laser beam is high at the center of the beam and low at the periphery. Therefore, by adjusting the laser irradiation output in a state where the laser beam is irradiated so that the irradiation spot 6 becomes the required processing spot 7 or more in advance, the irradiated portion of the beam center is sufficiently heated and covered. A portion where the surface of the workpiece undergoes a physical change and is processed and the periphery of the beam is irradiated can be prevented from sufficiently raising the temperature to be processed. In the above marking apparatus, another marking method of the present invention is a marking method in which a laser beam emitted from a laser light source 1 is scanned by scanning means 2 and 3 to form a character, figure or symbol on a workpiece 5. In the method, the processing line width or the processing spot 7 generated on the workpiece 5 is controlled by adjusting the laser irradiation time.
Normally, the intensity of the laser beam is high at the center of the beam and low at the periphery. Therefore, by adjusting the laser irradiation time in a state where the laser beam is irradiated so that the irradiation spot 6 becomes the required processing spot 7 or more in advance, the irradiated portion of the beam center is sufficiently heated and covered. A portion where the surface of the workpiece undergoes a physical change and is processed and the periphery of the beam is irradiated can be prevented from sufficiently raising the temperature to be processed. The marking device of the present invention is characterized in that the laser light source 1 is a semiconductor laser. A semiconductor laser is a light source that is easy to control the output of laser light.
The size of the processing spot can be easily adjusted by the method described later.

The marking device of the present invention guides the laser light emitted from the laser light source 1 through a fiber 10. In particular, when the laser light source 1 is a semiconductor laser, a unique beam shape having a different divergence angle between the fast-axis and the slow-axis is shaped into a beam having a circular uniform divergence angle by a fiber. A remarkable effect of improving the visibility of characters, figures or symbols formed in a circular shape is produced. In order to solve the above-mentioned problem, a marking apparatus according to the present invention comprises a heating apparatus for heating a workpiece 5 in a marking apparatus including at least a laser light source 1 for emitting laser light and scanning means 2 and 3 for scanning the laser light. Means. Since the preheating can be applied to the workpiece by the heating means, the workpiece can be processed by causing a physical change with a small amount of laser light energy. In the marking device of the present invention, the heating means is a laser beam from a preheating laser light source different from the laser light source 1. By using the laser beam as the heating means, it is possible to concentrate and heat the required portion of the workpiece efficiently. The marking device according to the present invention is provided near the fiber 10 for guiding the laser light emitted from the laser light source 1,
A preheating fiber 13 for guiding laser light emitted from the preheating laser light source 12 is provided. By guiding the laser light from the laser light source 1 and the laser light from the preheating laser light source 12 with the respective fibers, the same optical system can be used simply by aligning the end faces of the respective fibers. . In the marking device of the present invention, a plurality of the preheating fibers 13 are arranged so as to surround the fiber 10 that guides the laser light emitted from the laser light source 1 at the center. Since the workpiece 5 can be heated symmetrically with respect to the laser light emitted from the laser light source 1, the shape of the processing spot 7 can be made circular, and the formed characters, figures, or symbols have good visibility. Become. In the marking device of the present invention, the workpiece 5 is a thin film or a paint formed on the surface of the object. The thin film or paint formed on the object surface
Many can be processed by relatively weak laser irradiation, and have high sensitivity to heating energy. Therefore, the effect of preheating by the heating means can be particularly obtained.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A marking device according to a first embodiment of the present invention will be described with reference to FIG. In FIG. 1, 1 is a laser light source, 2 and 3 are scanner mirrors used as scanning means of laser light, 4 is a condenser lens, and 5 is a workpiece. The difference from the conventional marking device in FIG. 10 is that the irradiation spot 6 of the laser beam 8 is configured to be larger than the required processing line width or the processing spot 7 on the workpiece 5. . Specifically, the irradiation spot 6 may be enlarged by disposing the workpiece 5 at a position shifted from the position of the beam waist 9 of the laser beam as shown in FIG. Alternatively, as shown in FIG. 3, the workpiece 5 is arranged so that the beam waist 9 coincides with the irradiation spot 6, and the light source used to make the beam waist 9 larger than the required processing line width or the processing spot 7. The size or the lateral magnification of the lens system may be designed. Various laser light sources can be used as the laser light source 1. In particular, when a semiconductor laser is used as the light source, the divergence angle is large, so that the beam waist is larger than the required processing line width or processing spot 7 as shown in FIG. The system is easy to configure and is preferred. The laser light from the laser light source 1 may be guided by a fiber. In particular, when the laser light source 1 is a semiconductor laser, a unique beam shape having a different divergence angle between a fast-axis and a slow-axis is shaped into a beam having a circular uniform divergence angle by a fiber. Has a remarkable effect such that the visibility of characters, figures, or symbols formed by improving the shape of a circle is improved. Usually, a laser beam has an intensity distribution close to a Gaussian distribution, and the intensity is high at the center of the beam and low at the periphery.
Therefore, when the laser irradiation output or the laser irradiation time is adjusted in the state shown in FIG. 2 or FIG. 3, the portion irradiated with the beam central portion is sufficiently heated and processed, and the portion irradiated with the beam peripheral portion is sufficiently heated. It can be prevented from being raised and processed. That is, the processing line width or the processing spot 7 smaller than the irradiation spot 6 of the laser beam 8
Can be formed on the workpiece. Therefore, a processing spot 7 smaller than the beam waist 9 can be obtained without changing the beam quality of the laser light source 1 and the performance of the condenser lens 4. The processing line width or the processing spot 7 can be controlled by adjusting the laser irradiation output or the laser irradiation time. However, the marking time can be shortened by controlling the processing line width or the processing spot 7 by adjusting the laser irradiation time while keeping the laser irradiation output at the maximum rating of the laser light source 1.
As described above, the marking on the workpiece 5 is performed by applying heat to the laser beam. Therefore, by preheating the workpiece 5 in advance, a state in which a physical change is likely to occur can be achieved. . That is, the marking can be performed with the laser beam 8 having less energy.
Therefore, the laser irradiation time can be shortened, the marking time can be shortened, and the productivity can be improved. Workpiece 5
Convection heating means such as a dryer that blows warm air, radiant heating means or oven using radiant heat from a high-temperature object placed around the workpiece, such as a heater. For example, a conductive heating means for heating the workpiece 5 in contact with the workpiece 5 or a combination thereof can be used. In particular, in order to efficiently preheat the workpiece 5, a laser light source for preheating is provided separately from the laser light source 1, and before or during the laser irradiation of the laser light source 1, the preheating laser light source is applied to the workpiece. What is necessary is just to irradiate a laser beam. The laser light source 1 and the preheating laser light source may be the same type of laser or different lasers. For example, both the laser light source 1 and the preheating laser light source may be a YAG laser, or the laser light source 1 may be a YAG laser and the preheating laser light source may be a semiconductor laser. When the laser light from the laser light source 1 is guided by the fiber, it is preferable that the laser light from the laser light source for preheating is also guided by the fiber for preheating. This is because the same optical system can be used only by aligning the end faces of the processing fiber for guiding the laser light source 1 and the preheating fiber. Furthermore, if a plurality of preheating fibers are arranged so as to surround the processing fiber, the laser beam emitted from the laser light source 1 can be symmetrically heated around the center, so that the shape of the processing spot 7 can be made circular. Thus, the visibility of the formed character, figure or symbol is improved.

(Embodiment 1) FIG. 4 shows a marking apparatus according to a first embodiment. In FIG. 4, 1 is a laser light source, 10
Is a fiber, 2 and 3 are scanner mirrors, 4 is a condenser lens, 5 is a workpiece, and 11 is a collimator lens.
A semiconductor laser was used as the laser light source 1, but a gas laser such as a carbon dioxide laser, a He—Cd laser, an Ar laser, or an excimer laser, a solid laser such as a YAG laser, a YLF laser, a glass laser, and a fiber laser, and a liquid of dye laser. A harmonic laser light source that emits a laser beam having a wavelength of a harmonic component by combining with a laser or a nonlinear optical crystal can also be used. The rotation of each of the scanner mirrors 2 and 3 used as scanning means can be controlled by a scanner motor (not shown). As the scanning means, an XY stage may be used so that the relative position between the laser beam emitted from the marking device and the workpiece 5 changes. Arbitrary optical components such as a collimator lens and a beam expander can be arranged between the laser light source 1 and the scanner mirror 2. As the condenser lens 4, an fθ lens was used. As the workpiece 5, a chromium film 52 deposited on a glass substrate 51 was used. As the workpiece 5, any other material that causes a physical change (for example, peeling, vaporization, burning, foaming, bulging, discoloration / discoloration, or the like of the surface or a surface layer) on the surface by a laser beam may be used. it can. For example, acrylic resin, epoxy resin, polyimide resin, P
VC resin, olefin resin, resin materials such as ABS and PET, silicon wafers, metal materials, glass and the like can be used. Further, the workpiece 5 may be a thin film or a paint formed on a bulk surface of such a resin-based material or a metal-based material. Further, the workpiece 5 can be used as a thin film or a paint such as a color filter formed on the front surface or the back surface of a transparent material such as glass and acrylic. In the marking device having the above configuration, the beam waist 9 of the laser beam 8 is set to 20 to form a 20 × 20 matrix two-dimensional code with a segment diameter of 100 μm.
The fθ lens was selected to be 0 μm. As shown in FIG. 5, the chromium film 52 was arranged at the position of the beam waist 9. In FIG. 5, the chromium film 52 is
1, the laser beam 8 is irradiated through the glass substrate, but the laser beam 8 may be directly irradiated with the chromium film 52 facing upward. In the above marking apparatus, the output of the laser light source 1 was maximized, and the chromium film 52 was irradiated with laser light for an irradiation time of 100 ms. As a result, the diameter of the processing spot 7 formed on the workpiece 5 became 200 μm. Next, the laser light source 1
By reducing the output of, a processing spot 7 having a minimum of 50 μm could be obtained. In addition, by shortening the irradiation time while keeping the output of the laser light source 1 constant, a processing spot up to a minimum of 50 μm could be obtained. FIG. 6 shows the result of marking the two-dimensional code with the irradiation time set to 15 ms. Desired segment diameter 1
A 20 × 20 matrix could be formed at 00 μm. As described above, by using the marking device shown in the first embodiment of the present invention, the size of the processing spot can be varied by adjusting the output or irradiation time of the laser beam, which is conventionally required. The need for an adjusting mechanism or a diaphragm for adjusting the distance from the condensing lens to the workpiece is eliminated.

(Embodiment 2) FIG. 7 shows a marking apparatus according to a second embodiment. The difference from the first embodiment is that a laser light source 12 for preheating and a fiber 13 for preheating are added. The preheating fiber 13 includes a plurality of fibers, and is bundled around the fiber 10 for guiding the laser light from the laser light source 1 as shown in FIG. It is also possible to simplify the configuration of the fiber portion and adopt a configuration in which the preheating fiber 13 is simply arranged adjacent to the fiber 10 as shown in FIG. In the configuration of FIG. 7, when the preheating laser light source 12 irradiates a preheating laser light before or during marking, the workpiece 5 can be heated symmetrically around the laser light 8 emitted from the laser light source 1. . Therefore, the laser irradiation time of the laser light source 1 required to obtain the same processing spot 7 can be greatly reduced as compared with the case where there is no laser beam for preheating. Since it is heated symmetrically, the shape of the processing spot 7 is also circular. In the experiment, the output of the laser light source 12 for preheating was set to 50% of the output of the laser light source 1, and the time for obtaining the same size of the processing spot 7 could be reduced to 2/3 of that without preheating. . As described above, by applying preheating to the workpiece, the laser irradiation time can be shortened, so that the marking time is shortened and the productivity is increased. Although the preheating laser light source 12 is separately provided in the second embodiment, a part of the laser light of the laser light source 1 is guided by the preheating fiber 13 as shown in FIG. 9 and the preheating laser light source 12 is omitted. It is also possible. This configuration,
In the first embodiment, the size of the light source is increased and the irradiation spot 6 is increased.
Is larger than when. Specifically, the first
In practice, it was sufficient to irradiate the laser beam for 15 ms in order to obtain a processing spot 7 of 100 μm.
An irradiation time of 25 ms was required to obtain m processing spots. That is, the processing time could be shortened by heating the processing spot portion with the laser beam irradiated outside the range of 100 μm in diameter corresponding to the processing spot.

[0009]

As described above, by using the marking device of the present invention, the processing line width or the size of the processing spot can be changed by adjusting the output or irradiation time of the laser beam. There is no need for an adjusting mechanism or a diaphragm for adjusting the distance from the condenser lens to the workpiece, which has the effect of simplifying the device configuration and reducing the device cost. Further, by using the marking device of the present invention, the workpiece can be preheated, so that the workpiece undergoes a physical change (for example, peeling of a surface or a surface layer, vaporization, burning,
Foaming, bulging, discoloration, bleaching, etc.)
The laser irradiation time can be shortened, and there is an effect that the marking time is shortened and the productivity is increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a laser marking device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a workpiece showing a first laser irradiation method according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a workpiece illustrating a second laser irradiation method according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a laser marking device according to a first embodiment of the present invention.

FIG. 5 is a cross-sectional view of a workpiece illustrating a laser irradiation method according to the first embodiment of the present invention.

FIG. 6 is a photograph of a two-dimensional code marked in the first embodiment of the present invention.

FIG. 7 is a schematic view showing a laser marking device according to a second embodiment of the present invention.

FIG. 8 is a sectional view showing an arrangement of fibers according to a second embodiment of the present invention.

FIG. 9 is a schematic view showing another embodiment of the second embodiment of the present invention.

FIG. 10 is a schematic diagram showing a conventional laser marking device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Laser light source 10 Fiber 2 Scanner mirror 11 Collimator lens 3 Scanner mirror 12 Preheating laser light source 4 Condensing lens 13 Preheating fiber 5 Workpiece 51 Glass 52 Chrome film 6 Irradiation spot 7 Processing spot 8 Laser light 9 Beam waist

Claims (12)

[Claims] 1. A laser marking apparatus comprising: a laser light source that emits a laser beam toward a surface portion of a workpiece; and a scanning unit that scans the laser beam. A laser marking device characterized in that it is larger than the width of a processing line or the diameter of a processing spot to be processed on a surface portion of a workpiece. 2. The laser marking device according to claim 1, wherein said laser light source is a semiconductor laser. 3. The laser marking device according to claim 1, wherein the laser light emitted from the laser light source is guided by a fiber. 4. A laser marking apparatus comprising: a laser light source for emitting a laser beam toward a surface portion of a workpiece; and a scanning unit for scanning the laser beam. The laser marking apparatus further comprises a heating unit for heating the workpiece. A laser marking device. 5. The laser marking apparatus according to claim 4, wherein said heating means is a laser beam from a laser light source for preheating different from said laser light source. 6. A processing optical fiber for guiding laser light emitted from the laser light source, and a preheating fiber for guiding laser light emitted from the preheating laser light source is provided in the vicinity thereof. The laser marking device according to claim 5, wherein: 7. The laser marking apparatus according to claim 6, wherein a plurality of said preheating fibers are arranged so as to surround said optical fiber for processing. 8. The laser marking apparatus according to claim 1, wherein the workpiece is a thin film or a paint formed on a surface portion of the object. 9. The method according to claim 1, wherein the workpiece is a thin film or a paint formed on the surface of the permeate.
8. The laser marking device according to any one of items 1 to 7. 10. The laser marking apparatus according to claim 1, wherein the workpiece is a chromium film or a color filter film formed on a glass plate. 11. A marking method in which a laser beam emitted from a laser light source is scanned by scanning means to form a character, a figure or a symbol on a surface portion of a workpiece, by adjusting an irradiation output of the laser beam. A laser marking method characterized by controlling a processing line width generated on a workpiece or a diameter of a processing spot processed by laser light irradiation. 12. A marking method in which a laser beam emitted from a laser light source is scanned by a scanning unit to form a character, a figure or a symbol on a surface portion of a workpiece, by adjusting an irradiation time of the laser beam. A laser marking method characterized by controlling a processing line width generated on a workpiece or a processing spot processed by laser light irradiation.