JPS6220897A - Method for patterning valve metal - Google Patents

Abstract

PURPOSE:To accurately decorate with even a complicated pattern by arranging a masking member having a light transmission face on the upper surface of or above a valve metal before or after anodization and irradiating laser light on the surface of the valve metal through the light transmission face of the masking member. CONSTITUTION:A masking member 5 is arranged above an anodized valve metal 1 slightly away from the metal. A light transmission face 6 having a specified pattern through which laser light 3 can be passed is formed on the masking member 5. The laser light 3 having smaller spot diameter than the light transmission face 6 of the masking member 5 is transmitted through the light transmission face 6 through a convex lens 4 while being reciprocated along an imaginary line 8 and passed through the whole region of the light transmission face 6. A pattern similar to that of the light transmission face 6 is drawn on the surface of the valve metal 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of depicting a visually visible pattern by applying a laser beam to a valve metal colored by anodizing treatment.

[Prior art] Titanium (Ti), zirconium (Zr), tantalum (T
a) etc. are sometimes called valve metals. The reason for this is that the oxide layer on these metals has a so-called valve effect, allowing current to pass in only one direction and hardly passing current in the opposite direction. In addition to the above metals falling under the above definition, Al, V, Y, Nb
, In, La, Hf.

WAs- are known. It is also known that some of these valve metals have an oxide film formed on their fully curved surfaces by anodizing, and appear colored due to the interference effect of light on the film.

Various methods are known for further drawing patterns on the surface of the colored valve metal obtained by the above-mentioned anodic oxidation treatment. Examples of these methods include (1) a printing method;
(2) Manual method using a brush or pen, (3) Method 5 of anodic oxidation using local masking, etc., but each method includes the problems listed below.

(1) Disadvantages of the printing method (a) Since it is a contact process, chemical contamination and coloring unevenness may occur on the valve metal surface due to printing ink, etc., resulting in a lack of quality stability.

(b) Although the anodized surface retains the luster characteristic of metals, this luster is lost by printing.

(C) It is necessary to select an appropriate printing ink, and special pretreatment may be necessary to improve the adhesion of the printing ink.

(2) Disadvantages of manual methods using brushes and pens (a)
Since it is a contact process, there is the same problem of contamination of the valve metal surface as with the (+) method.

(b) It is impossible to develop a color unique to the material [same problem as in the (1) method] (c) A M training engineer is required, and individual differences depending on the skill level, running ability, etc. of the worker become noticeable.

(d) It takes a long time and is not suitable for mass production.

(e) There will be variations in the quality of the product, resulting in a lack of quality stability.

(3) Disadvantages of the method of anodic oxidation using local masking In this method, the surface to be colored is locally masked using the L method, such as applying a masking resin in accordance with the pattern desired, and then anodized. This is a method of obtaining a predetermined colored pattern and then separating the resin by 2+1. Therefore, in this method as well, (a) contact processing is required, and there is a problem of contamination of the valve metal surface.

(b) One process of masking → coloring → mask removal → drying is required for each color to be colored, and the productivity is low and it is not suitable for mass production.

(c) Precise and fine processing is difficult, and quality stability is lacking.

There are other problems.

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned problems, and therefore, its purpose is to facilitate automation and mass production, and to obtain products of good quality. The purpose of this invention is to provide a possible pattern depiction method.

[Means for Solving the Problems] The present invention includes disposing a mask member having a transparent surface on or above the valve metal before or after anodizing treatment,
The gist is that a surface pattern similar to or congruent with the transparent surface of the valve metal is drawn on the valve metal by irradiating the surface of the valve metal with laser light through the transparent surface of the mask member.

[Function] The present invention is a pattern drawing method configured as described above,
The biggest feature is that a mask member having a light-transmitting surface is placed on or above the valve metal, and a laser beam is irradiated onto the valve metal surface through the light-transmitting surface of the mask member. It attempts to depict surface patterns that are similar or congruent with the surface.

The principle of the present invention is to apply a thermal change induced by irradiating the valve metal surface with laser light before or after anodizing. In other words, if the valve metal surface is irradiated with a laser beam before anodizing, the irradiated area will receive a different blue effect from other areas even if anodizing is performed, and the area will have a different blue color effect after anodizing. When the surface of the presser metal 14 is irradiated with laser light, only the irradiated area of the already colored valve metal surface changes color. In this way, a visually visible pattern can be drawn on the valve metal surface.

Thermal changes induced on the valve metal surface by laser treatment are based on the rapid local heating and then rapid cooling of the valve metal surface, resulting in changes in the structure of the material, distortion, and deterioration or disappearance of the oxide film. It appears as . The type of thermal change and the region in which it is induced are determined by the irradiation conditions, provided that the material properties, ie, thermal conductivity, laser light absorption rate on the surface, etc., are the same. The irradiation conditions generally include the laser oscillation output, the beam convergence area, the interaction time between the irradiated material and the laser beam, etc., but as values including these, the following equations (1) and (2) are used. As shown, there is power density and energy density.

(1) In the pattern drawing method according to the present invention, the valve metal surface is not etched (generated by surface evaporation), so the appropriate range of irradiation conditions is determined by the following equations (3) and (4). As shown in the formula.

103W/c■3 power density<l07W/c2...
・(3) 102J/c112<Energy density<10
4J/am2 (4) Any irradiation conditions can be selected depending on the pattern desired to be depicted, as long as the conditions satisfy equations (3) and (4) at the same time. Each factor of the irradiation conditions and the scanning of the laser beam can be easily controlled and can be computerized. This makes it easy to set the pattern to be drawn, resulting in good pattern reproducibility and stable product quality. Furthermore, high-speed depiction becomes possible, and mass production can be achieved.

The laser beam used in the present invention causes a thermal change on the valve metal surface.
The power density and energy density may satisfy the conditions that can be achieved, that is, the above-mentioned formulas (3) and (4).Therefore, (a) type of laser (CO2k/- laser, YAG laser, etc.) (b) oscillation Method (continuous oscillation, pulse oscillation, etc.) (C) Beam mode (single mode, multimode, etc.) is not limited to 4'F.

A supplementary explanation of the principle of light interference is as follows. If there is a change in the medium through which light propagates, reflection will always occur at the boundary. Therefore, as shown in Fig. 2, if there is a thin film with a refractive index n1 and a thickness d between media with refractive indexes nQ and n2, then the wavelength-incident light that is incident on this thin film at an incident angle α will reach the boundary F above the film. When the incident length is monochromatic (single wavelength), multiple interference occurs due to repeated reflections, and depending on the film thickness, they become stronger or weaker depending on the Bragg (W, L, Bragg) reflection condition. In the case of natural light, each wavelength in the visible region is layered or superimposed to produce color. That is, if the film thickness differs, the above-mentioned interference conditions will change, and different colors will appear. Therefore, even if the same metal plate is anodized, the color may appear different depending on the treatment conditions.

The details of why one color looks different when laser treatment is applied after anodizing treatment are unknown, but
It can be considered as follows.

That is, it is thought that this is because the surface is oxidized due to absorption of laser light and the oxide film thickness changes. In addition, the addition of heat may cause changes in film crystallinity, chemical composition, cracks, porosity improvement, surface roughness, irregular internal boundaries, density fluctuations, etc.

The present invention basically irradiates the valve metal surface with a laser beam before or after anodizing treatment, but as shown in the example below, the valve metal surface may be irradiated with a laser beam after anodizing treatment. TiO2 absorbs light of 10.6 pm (the wavelength of the CO2 laser) well, but Ti reflects more than 90% of the light. Therefore, even if heat is applied to the extent that only the surface acid film is evaporated, the Ti plate will hardly change or at most will melt.

After that, an anodizing process is performed on the flame to form an oxide film that is thinner than the original thickness only on the part where the oxide film was removed by laser processing. As mentioned above, different colors appear when the film thickness is different.

[Example] Ti plate material [300' x 3001' x
3.0' (am)], and the steps up to anodization were performed in the following steps. rTi rolling → surface degreasing → pickling → cleaning → anodizing treatment 1 Next, as shown in Figure 1 (Jll schematic diagram), a mask is placed over the obtained anodized press Jul with a slight interval. A member 5 was placed, and a laser beam 3 was irradiated from above the mask member 5. The laser beam 3 was focused by a convex lens 4 as a focusing member.

On the other hand, the mask member 5 is formed with a light-transmitting surface 6 through which the laser light 3 can pass, and the light-transmitting surface 6 is larger than the spot diameter of the laser light 3 passing near the light-transmitting surface 6. The mask member 5 may be made of, for example, AI, or any other material that reflects the laser beam 3, and the transparent surface 6 is only referred to as "one surface" for convenience of explanation, and of course may be made of glass or the like. The mask member 5 may be made of a light-transmitting member, or may be a mask member 5 with a predetermined portion cut out. The transparent surface 6 is formed on the mask member 5 in order to depict a pattern corresponding to the transparent surface 6 on the surface 2 of the mask member 5, and in the case of a complex shape, it cannot be solved by simply forming a notch. There is.

It can be determined depending on the case.

As shown in FIG. 1, the laser beam 3 having a spot diameter smaller than the light-transmitting surface 6 of the mask member 5 is transmitted through the light-transmitting surface 6 while reciprocating along the imaginary line 8. is operated so that the light passes through the entire area of the transparent surface 6. Then, the laser beam 3 transmitted through the light-transmitting surface 6 is irradiated onto the surface 2 of the valve metal 1 with a spread corresponding to the light-transmitting surface 6. As a result, a surface pattern 7 having a shape similar to that of the light-transmitting surface 6 is drawn on the surface 2 of the valve metal l, as shown in FIG. The surface pattern 7 is indicated by hatching in Fig. 5 to clarify its area.The surface pattern 7 is drawn on the surface 2 of the valve metal l as described above. For metal l, a golden surface pattern was drawn on a Ti plate material that had been colored h-color by anodizing.

The irradiation conditions of the laser beam 3 used were as follows.

(Laser beam irradiation conditions) Laser oscillator: CO2 laser (wavelength 10.8gm) Oscillation method: Continuous oscillation output: 5KW Beam spot diameter: 53cm Travel speed: 15m/l 1in'' In the double example, laser beam 3 is sent back and forth. Although the laser beam 3 is configured to move and pass through the entire area of the transparent surface 6, the laser beam 3 may be kept in a fixed state and the valve metal 1 and the mask member 5 may be moved integrally. are the valve metal 1 and the mask member 5
It is also possible to move the laser beam 3 integrally and to move the laser beam 3 back and forth.

The present invention describes a pattern on the valve metal 1 by irradiating the surface 2 of the valve metal 1 with a laser beam 3, and the mask member 5
is for defining the portion through which the laser 3 passes, that is, the portion where the surface pattern 7 is to be depicted. Therefore, there is no fear that the surface 2 of the valve metal 1 will be contaminated by the mask member 5, etc., and the mask member 5 is not limited to the case where the mask member 5 is spaced upward from the surface 2 of the valve metal 1. In this case, a surface pattern 7 having a shape congruent with the transparent surface 6 is drawn on the surface 2 of the valve metal 1.

FIG. 3 is a schematic explanatory diagram of another embodiment of the present invention. The spot area of the laser beam 3 irradiated onto the mask member 5 is as indicated by a broken line 9 in the figure, and is adjusted so that the light-transmitting surface 6 of the mask member 5 falls within the spot area 9. The laser beam after passing through the transparent surface 6 is focused by the convex lens 4 and irradiated onto the surface 2 of the valve metal 1 which has been anodized.

In this configuration, a similar shape obtained by reducing the shape of the transparent surface 6 can be drawn on the surface 2 of the valve metal 1 without moving the laser beam 3 and/or the valve metal 1.

As a still further embodiment of the present invention, as shown in FIG. The surface 2 of the treated valve metal 1 may also be irradiated. In this case, the light-transmitting surface 6 is arranged to fit within the spot area 9 of the laser beam 3 after being focused. With this configuration as well, the same effects as the embodiment shown in FIG. 3 can be obtained.

In the embodiment shown in FIGS. 3 and 4, a configuration in which the laser beam 3 is focused by a convex lens 4 is adopted, but a concave lens is used instead of the convex lens 4, and the shape of the light-transmitting surface 6 of the mask member 5 is It is also possible to depict an enlarged surface pattern 7 with a similar shape.

In addition, the structure is not limited to lenses, and a configuration that employs a reflecting mirror such as a concave mirror may be used.

By employing the above-described configuration, patterns with complex shapes can be depicted with high precision, quality can be stabilized without causing variations between products, and large J4 production is also possible.

Although the embodiments shown in Figures 1 to 4 are described assuming that the surface 2 of the valve metal 1 is irradiated with the laser beam 3 after the valve metal 1 is anodized, the present invention is also applicable to the following. Embodiments such as those listed may also be adopted.

(A) Before applying anodizing treatment, the surface 2 of the valve metal l is irradiated with a laser beam 3 to induce a thermal change on the surface 2 of the valve metal l due to the irradiation of the laser beam 3, and then anodizing treatment is applied to the valve metal l. A method of drawing a surface pattern 7 on a surface 2 of a metal 1.

(B) A method in which the surface 2 of the valve metal 1 is irradiated with a laser beam 3 after anodizing treatment, and then the anodization treatment is performed again to add a colored surface pattern to the surface 2 of the valve metal 1.

(C) After anodizing, the surface 2 of the valve metal 1 is irradiated with laser light 3, and the heat that reaches the surface opposite to the irradiated surface (referred to as the back surface) changes the quality of the fertilized film on the back surface. 1M1
A method of depicting a colored surface pattern on the back side of valve metal l by changing the texture, etc.

(D) A method that combines the two methods (A) to (C).

Any of the methods (A) to (D) described above is included within the technical scope of the present invention.

[Effects of the Invention] As described above, according to the present invention, by employing the above-described configuration, complex patterns can be accurately depicted and quality can be stabilized without causing variations between products. , mass production became possible.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the principle of light interference, and FIG. 3 is a diagram showing a valve metal 1 according to the present invention.
Figure 4 showing a state 7f depicting the surface pattern 7 on the surface 2 of
The figure is a schematic explanatory diagram of another embodiment of the present invention, and FIG. 5 is a schematic explanatory diagram of still another embodiment of the present invention.

Claims (1)

[Claims] A method for drawing a pattern on a valve metal colored by anodizing treatment, wherein a mask member having a transparent surface is placed on or above the valve metal before or after the anodizing treatment, and the mask member 1. A method for drawing a pattern on a valve metal, the method comprising: irradiating the surface of the valve metal with a laser beam through the light-transmitting surface of the valve metal to draw a surface pattern similar to or congruent with the light-transmitting surface of the valve metal.