JPS6061193A - Laser inscribing method - Google Patents

Abstract

PURPOSE:To perform laser inscribing to a transparent material by disposing the transparent object and an absorptive material apart from each other, evaporating the absorptive material by laser light to deposit the vapor thereof on the transparent object and irradiating the laser light at the same instant to a part of the deposited part of the transparent object. CONSTITUTION:An absorptive material base 3 is placed on a table 4 and further a transparent object 2 is disposed thereon at a space 6 apart from each other. When laser light 1 is made incident to the object 2 from the upper side thereof, the light 1 transmits the object 2 and irradiates the base 3. The absorptive material is thus evaporated or sublimated and is deposited on the surface of the object 2 facing the irradiated surface. The light 1 irradiates partly the deposited part thereof and therefore an inscribed part 5 is formed on the deposited surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to a method of marking an object using a laser beam through which the laser beam used is transmitted.

[Prior art and its problems]

Conventionally, when using a laser beam to mark an object through which the laser beam passes (hereinafter referred to as a transparent object), a reflective film (hereinafter referred to as a reflective film) that has a high reflectance for the laser beam is applied to the transparent object. It is known that a thermal processing method is employed in which laser light is focused on the interface between a reflective film formed on the surface of a transparent object and a transparent object. According to such prior art, it is necessary to form a reflective film on a transparent object in advance and to remove the reflective film after laser beam irradiation, that is, after marking. In addition, there is also known a method in which laser light is incident on the surface-finished side of a transparent object, focused on the back surface of the object, and laser processing proceeds from the back surface of the object in the direction in which the laser beam is incident.

However, in this conventional technique, when processing a transparent object with a low absorption rate of laser light, there is a large energy loss and it is necessary to essentially concentrate a large amount of energy on the processing portion of the transparent object.

Therefore, in this case, for example, YA with a wavelength of 1.06 μm
Although it is possible to process objects with a low coefficient of thermal expansion such as quartz glass using a G laser, it is possible to process objects with a low coefficient of thermal expansion such as quartz glass, but objects with a high coefficient of thermal expansion and low thermal conductivity such as multi-component glasses including soda glass and lead glass In materials with a small coefficient of thermal expansion, thermal strain accumulates and breakage occurs during or after processing, making it practically impossible to engrave objects with such a high coefficient of thermal expansion and high brittleness.

[Purpose of the invention]

This invention was made in view of the above, and its purpose is to make it possible to mark a transparent object using a laser beam without requiring a reflective film to be formed on the transparent object in advance, and to concentrate the laser beam on the marking part. An object of the present invention is to provide a laser engraving method capable of engraving a highly brittle object with a high coefficient of thermal expansion by using a small amount of energy.

[Key points of the invention]

In order to achieve the above object, the present invention arranges an object that transmits a laser beam and a substance that absorbs the laser beam with an effective gap therebetween, and uses the laser beam as a heat source to absorb the laser beam. At the same time, the laser beam is applied to at least a portion of the object that transmits the laser beam to which the substance that absorbs the laser beam is adhered. By irradiating the object, the portion of the object that transmits the laser beam that is coated with the absorbing substance and is irradiated with the laser beam is caused to undergo deformation or alteration due to melting or softening. That is.

[Embodiments of the invention]

1 and 2 are conceptual diagrams showing an embodiment of the laser engraving method according to the present invention. In the figures, 1 indicates a laser beam, 2
3 is the transparent object, 3 is the absorbing material table, 4 is the table, 5 is the stamping part, 6 is the absorbing material, and 7 is the absorbing material adsorbed to the transparent object 2. The absorbing material table 3 and the transparent object 2 are placed on the table 4. is provided, and the gap 6 is formed as a recess in the absorbent material platform.

In this configuration, the transparent object 2 is laser engraved (engraved part 5) by moving (scanning) the laser beam 1 incident from above the transparent object 2 or by moving the table 4 with respect to the laser beam 1. It is. Then, the gap 6 is formed so that when the laser beam 1 passes through the transparent object 2 from the upper side of the transparent object 2 and is irradiated onto the absorbing material stage 3, the absorbing material stage 3 is evaporated or sublimated, and the opposite surface of the transparent object 2 is It is sufficient that a portion of the absorbing substance 7 evaporated or sublimated is deposited in a range as close to the beam diameter of the laser beam 1 as possible. This allows the laser beam 1 to pass through the transparent object 2 and irradiate the absorbing material table 3, and at the same time, the irradiated part of the absorbing material table 3 absorbs the energy of the laser beam 1,
It is heated, evaporates or sublimates, and partially adheres to the opposing surface of the transparent object 2. At least a part of the absorbing material 7 attached to the transparent object 2 absorbs the laser beam 1, generates high heat, melts or softens the absorbing material, and when the laser beam 1 stops irradiating the transparent object The marking portion 5, which was irradiated with the laser beam 1 of No. 2, rapidly cools and solidifies. Furthermore, in the portion of the transparent object 2 that is irradiated with the laser beam 1, an in-phase reaction or diffusion of the absorbing substance 7 occurs even if the transparent object 2 is not in a melted or softened state 5-, causing the transparent object 2 to change in quality.

As a result, the solidified or altered portion, that is, the stamped portion 5 forms a surface having a shape different from the surface of the transparent object 2 before irradiation with the laser beam 1, or a portion with a different refractive index.

By irradiating the laser beam 1 with the above-described method, the marking portion 5 is formed on the transparent object 2, and the amount of the absorbing material 7 that makes laser marking possible is deposited on the transparent object 2. The amount does not need to be so large that the laser beam l is completely blocked by the absorbing substance 7 deposited on the object 2.

The absorbing substance 7 is released over the entire solid angle on the open surface by evaporation or sublimation, but in reality, the amount of the absorbing substance 7 deposited to enable laser marking is almost the same as the appearance of the transparent object 2. The inventor of the present invention has clarified that a very small amount is sufficient to have no effect. When it is necessary to remove even a very small amount of absorbed material due to the application, it can be removed by simply wiping it with a dry cloth, without using extreme methods such as chemical etching. It is confirmed that it is possible.

Further, the density of the marking portion 5 can be adjusted not only by simply changing the output of the laser beam, but also by changing the size of the gap 6, or by repeating the marking operation at the same location. Furthermore, since it is possible to take advantage of the characteristics of laser beam processing, which allows for high speed, high precision, good controllability, and non-contact processing, it is possible not only to produce a wide variety of products in small quantities, but also to avoid damage and stains caused by contact with the engraved object. The quality of the vines is good and laser engraving is done.

Note that the application of this invention is not limited to flat transparent objects as shown in this embodiment, but can also be applied to engravings on curved objects such as glass cups and bottles without any problems. It is a vine. Also absorbing material table 3
Since it serves both as a support for the transparent object 2 and as an absorbing material 7 to be applied to the transparent object 2, it can normally be used as a support for the transparent object 2 or as a positioning jig.

For example, when marking transparent glass with a Q-switched YAG laser, the average output of the laser is However, when using the laser engraving method according to the present invention, an average laser output of about 8 watts (W) is enough to engrave, which extends the applicable range of laser engraving. can be expanded significantly.

〔Effect of the invention〕

According to this invention, a transparent object and an absorbing material are arranged with a gap between them, and the absorbing material is evaporated or sublimated by a laser beam to adhere to the transparent object. Since at least a portion of the area is irradiated, there is no need to form a reflective film on the transparent object in advance. In addition, most of the absorbing material attached to the transparent object that is irradiated with the laser beam is effectively involved in marking, so the energy of the laser beam can be effectively absorbed regardless of the absorption rate of the laser beam of the transparent object. There is no need to input large impact energy, and damage to the machined part due to accumulation of thermal strain can be prevented. Since the engraving on a transparent object is limited to the part through which the laser beam passes, it does not affect the parts that are not desired to be engraved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the concept of an embodiment of the laser marking method according to the present invention, and FIG. 2 is a sectional view taken along line 1-I in FIG. DESCRIPTION OF SYMBOLS 1... Laser beam, 2... Transparent object, 3... Absorbing material stand, 5... Marking part, 6... Gap, 7... Absorbing material. 9-2 71 Figure T 2 mouth

Claims (1)

[Claims] 1) An object that transmits the laser beam and a substance that absorbs the laser beam are arranged with an effective gap between them, and the laser beam is used as a heat source to evaporate or sublimate the substance that absorbs the laser beam, thereby emitting the laser beam. A laser engraving method characterized in that, at the same time, the laser beam is applied to an object that transmits the laser beam, and at the same time, the laser beam is inscribed on at least a part of the adhered part of the object that absorbs the laser beam, using the laser beam. .