JPH062167A - Production of metallic body having fine pore and production of light emitting body for lamp - Google Patents

Abstract

PURPOSE:To provide a production method for metallic body having a fine pore capable of accurately and efficiently forming a perpendicular and uniform superfine pore on the surface of various metallic bodies and suitable for producing various products represented by a light emitting body for lamp. CONSTITUTION:The fine pore 42 is formed in the metallic body 40 by forming a metallic layer 20 to be used for a resist on the surface of the metallic body 40 on which the fine pore is formed, anodic oxidizing the surface of the metallic layer 20 for resist to form a cathodic oxidation coating film 20 having many fine pores 22 and etching the anodically oxidized film 20 used as the resist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal body having fine holes and a method for producing a luminous body for a lamp,
Specifically, a method for producing a metal body having an ultra-fine hole that cannot be formed by a conventional processing method, and a light-emitting body for a lamp such as a filament for an incandescent light bulb produced by using such a metal body. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, an incandescent lamp has been regarded as one of the best light sources because of its light color, color rendering property and easy handling. However, the drawbacks such as low efficiency, short life, and high surface temperature have not been improved for many years. Even in the incandescent lamp of the tungsten filament which is mainly used at present, the light in the visible region that human eyes perceive is about 10%, and most of it is emitted as infrared light, which is very inefficient. It is a system.

In order to improve the luminous efficiency even a little, the filament temperature must be raised to the maximum,
Therefore, the life of the filament is shortened in inverse proportion to the efficiency. Although a halogen lamp or the like has improved the efficiency to some extent, it has not been a decisive improvement, and other drawbacks such as a high color temperature cannot be improved.

In recent studies, it has been reported that the cavity quantum electrodynamic theory is applied to improve the efficiency of lamp filaments. For example, Japanese Patent Laid-Open No. 3-1027
In the publication No. 01, the bottom has a square of 350 nm and the depth is 700.
Providing a large number of minute holes or cavities with a prismatic shape of about 0 nm significantly reduces the radiation in the wavelength region of 700 nm or more, and can satisfactorily emit only visible light. As a result, the luminous efficiency is significantly increased. It is said that it can be improved to.
That is, the input power to the filament is less likely to be converted into radiation in the infrared region, that is, heat, and most of the input energy is used as visible light, which can be a very efficient light emitter.

[0005]

[Problems to be Solved by the Invention] As described above,
Although it is possible to manufacture an efficient lamp luminous body by providing a large number of fine holes on the surface of the filament for a lamp, it is necessary to form such fine holes on the surface of a filament material such as tungsten. Is very difficult, and no practically usable method has been found in terms of processing accuracy and economy.

That is, dimensional conditions such as the cross-sectional shape and depth of the fine holes and the thickness of the partition wall that separates the adjacent fine holes are directly related to the wavelength of the light emitted from the filament, and the luminous efficiency is greatly influenced. However, for example, 3
It is impossible to find a manufacturing method capable of accurately and efficiently processing a 50 nm square fine hole vertically with a depth of 7 μm and also applicable to industrial scale production.

[0007] Usually, when performing such fine processing, a processing method applying a photolithography technique which has been widely used conventionally can be considered. However, the most advanced mask technology,
Even with the use of exposure technology, it is extremely difficult to machine the ultra-fine holes described above, and in order to be able to actually process the holes, it will be necessary to improve the technology and develop the technology, and it will take time. It is expected to be. Even if the processing becomes possible, it is not practical if the cost is high, the processing time is long, or only a very small area can be dealt with.

The problems associated with the processing of the fine holes are as follows.
Not only when trying to obtain a lamp filament with high luminous efficiency, but also when manufacturing various applications or products that require controlling the wavelength distribution of various device parts that emit light, electromagnetic waves and other radiation. , A similar problem is occurring. Therefore, an object of the present invention is to make holes as described above on the surface of various metal bodies accurately and efficiently, and to make fine holes suitable for the production of various products typified by lamp light emitters. Another object of the present invention is to provide a method for manufacturing a metal body having

[0009]

In order to solve the above-mentioned problems, a method for producing a metal body having fine holes according to the present invention comprises forming a metal layer for a resist on the surface of a metal body having fine holes, After the surface of this resist metal layer is anodized to form an anodized film having a large number of fine holes,
By using this anodic oxide film as a resist and performing an etching process thereon, fine holes are formed in the metal body.

As the metal body for forming the fine holes, any metal material is used according to its purpose and use. For example, a high-melting-point metal such as tungsten, molybdenum, or an alloy mainly containing these metals is generally used as the light-emitting body for a lamp, but other metal materials can also be used. As the metal layer used as a resist, any metal material can be used as long as it can form an oxide film of the metal by an anodizing method and vertical fine holes are formed in the formed anodizing film. . Specifically, aluminum, titanium, zinc, and the like are preferable metal materials. When these metal materials are immersed in an acidic solution and subjected to anodic polarization, an oxide film having cylindrical fine holes perpendicular to the metal surface is formed. I do. Therefore, the thickness of the metal layer serving as the resist layer may be such that the function of the etching treatment can be sufficiently exerted, and specifically,
A material having a thickness of about 0.5 to 3 μm is used.

In the anodic oxidation treatment of the resist metal, the size and depth of the fine holes differ depending on the applied potential at the time of anodic oxidation, the type of oxidizing solution, the treatment time and the like. Therefore, it is desirable to determine the treatment conditions of the anodizing step in accordance with the intended use and required performance of the metal body. Specifically, under normal manufacturing conditions, the cross-sectional diameter of the fine holes is 10
A film having a depth of about 0 to 500 nm and a depth of about 0.5 to 3 μm is formed. Further, the thickness of the partition wall that separates adjacent fine holes is about 20 to 200 nm.
In the case of this anodic oxide film for resist, it is preferable that the depth of the fine holes reaches the entire thickness of the metal layer, and the narrower the distance from the bottom surface of the fine holes to the lower surface of the metal layer for resist, the easier the etching treatment. .

In this way, after the resist layer of the anodic oxide film having the fine holes is formed, the etching process is performed on the resist layer. The etching treatment is performed under such treatment conditions that the target metal body formed on the lower side through the fine holes of the resist anodic oxide layer can be etched to a predetermined depth.
However, it is preferable that the portions other than the fine hole portions of the resist layer are not etched as much as possible, since the target metal body can be processed into a deep shape. Specifically, although it depends on the type of metal used as a resist, carbon tetrafluoride CF ₄ or 6
Dry etching such as ECR plasma etching or reactive ion etching or wet etching using hydrofluoric acid or nitric acid can be performed using sulfur fluoride SF ₆ or the like as an assist gas.

By the etching treatment, vertical fine holes having the same sectional shape as the fine holes of the resist oxide film are formed in the metal body. The depth of the fine holes can be freely set according to its application and required performance. When a metal body having fine holes is used as a light emitting body for a lamp, it is desirable to set the depth of the fine holes to about 1 to 7 μm. After the etching treatment, the resist layer covering the surface of the metal body is removed by a method such as dissolution, and further, the substrate portion is removed by mechanical polishing or wet dissolution, whereby a metal body having fine holes on the surface is obtained. can get. If it is not necessary to remove the resist layer, it can be used as it is. This metal body is
It can be used as it is for the intended purpose, but it is also possible to join this metal body to another part or to subject the metal body to another treatment to produce the final product. .

The above-mentioned luminous body for a lamp or a filament is preferable as the use of the metal body having the fine holes, but it can also be used for various products having the same problems as the luminous body for a lamp. is there. The size and shape of the fine holes formed in the metal body are variously set according to each application. Especially in the case of lamp light emitters,
The wavelength distribution of the emitted light changes depending on the diameter of the micro holes, so for normal lighting that requires visible light, the wavelength is 700 nm.
The size of the microholes is set so as to eliminate the radiation in the infrared region above. However, depending on the application of the lamp, it may be necessary to radiate in the infrared region or a wavelength region that is shorter than visible light, and the size and shape of the microholes should be set according to each case. do it.

[0015]

When an anodic oxide film is formed on the surface of a metal such as aluminum, many vertical fine cylindrical holes are formed in the anodic oxide film. The shape of the fine holes is a uniform fine hole in which the ratio of the depth of the holes to the cross-sectional diameter, that is, the aspect ratio is very large and the sizes are relatively uniform. With this method, you can machine individual holes,
Since the photolithography technique is not used, it is possible to manufacture a product having a large area with a desired micro hole very easily and efficiently. By appropriately setting the conditions for forming the anodized film, it becomes possible to form uniform fine holes having a high aspect ratio, which cannot be realized by conventional processing techniques.

In the present invention, the anodic oxide film as described above is used as a resist in the etching process. That is, by forming a metal layer for a resist layer on the surface of a target metal body and subjecting this metal layer to anodizing treatment, a resist layer having a large number of fine holes can be formed. From above anodized film resist layer,
When the etching process is performed, since the thickness of the resist layer in the portion of the fine holes is very thin, the surface of the metal body under the resist layer can also be etched. Since the resist layer is thickly covered where there are no fine holes, the underlying metal body is not exposed and the metal body is not etched. Therefore, on the surface of the target metal body, the same size as the anodic oxidation resist layer formed thereon is etched in the vertical direction to form fine irregularities.

That is, in the present invention, the pattern of fine holes formed when the metal layer to be the resist is anodized is used as the resist pattern when etching the metal body. The fine holes in the anodic oxide film have an advantage in that it is possible to relatively easily form an ultrafine pattern that is difficult to achieve by pattern formation by ordinary mechanical processing or a photolithography method using a polymer resist. As a result, the shape of the fine holes formed on the target metal body surface is also a fine and relatively uniform processed surface. It can also be applied to products with large areas.

When the metal body having fine holes manufactured in this manner is used as a light-emitting body for a lamp, a large number of fine vertical holes having a high aspect ratio are provided. It becomes possible to radiate only visible light efficiently. Therefore, a light-emitting body for a lamp having extremely high luminous efficiency can be easily manufactured at low cost.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a stepwise schematic view showing a method of manufacturing a metal body having fine holes according to an embodiment of the present invention. First, as shown in FIG. 1 (a), on a substrate 10 made of alumina, silicon, or the like, by using a film forming means such as sputtering, vacuum deposition, or CVD, tungsten or the like, which is a material for a light-emitting body for a lamp, is formed. The metal body 40 is formed. A metal layer 2 serving as a resist layer on the metal body 40
Form 0.

As shown in FIG. 1B, when the metal layer 20 for resist is anodized in an acidic solution, the metal layer 20 is
Is anodized, and a large number of fine holes 2 are
2 is formed. The fine holes 22 are formed to a depth reaching near the surface of the lower metal body 40. As shown in FIGS. 1C to 1D, the metal body 40 is etched by using the resist layer 20 having the fine holes 22 as a resist. Etching is performed on the thin resist layer 20 remaining on the bottom of the fine hole 22.
After etching, the metal body 40 is etched, and the metal body 40 is dug vertically downward according to the cross-sectional shape of the fine holes 22 of the resist layer 20. As a result, fine holes 42 corresponding to the shape of the fine holes 22 are also formed on the surface of the metal body 40.

When the fine holes 42 having a predetermined depth are formed in the metal body 40, the etching process is completed, and the resist layer 20 remaining on the surface of the metal body 40 is dissolved as shown in FIG. 1 (e). By removing and further removing the substrate 10 of the metal body 40 by mechanical grinding, melting or the like, the metal body 40 in which the desired fine holes 42 are formed can be obtained. FIG. 2 shows a schematic structure of a light emitter for a lamp, which is a metal body having fine holes manufactured as described above. A large number of cylindrical fine holes 42 are formed on the surface of the luminous body for a lamp which is made of the tungsten layer 40.
Are formed. In the figure, all the micro holes 42 are drawn with the same cross section and depth, but in reality, the micro holes 42 are etched according to the shape of the micro holes 22 formed in the resist layer 20 of the anodized film. There are variations and distributions in the shape. However, practically, the fine holes 42 having a substantially uniform shape are formed.

The diameter D and the depth H of the fine holes 42 differ depending on the processing conditions at the time of forming the anodic oxide film which is the resist layer, but in the case of an ordinary lamp luminous body, the diameter D = 30.
Those having a depth of 0 to 400 nm and a depth of 5 to 7 μm are used. Next, more specific examples will be described. -Example 1- According to the process shown in FIG. 1, the metal body used as the light-emitting body for lamps was manufactured.

A metal body 40 made of tungsten and having a thickness of about 10 μm was formed on the surface of the alumina substrate 10 by the RF sputtering method. A resist metal layer 20 made of aluminum was formed on the metal body 40 by RF sputtering to a thickness of about 10 μm. This tungsten-aluminum joined body was immersed in a phosphoric acid aqueous solution, and a potential of 150 V was applied to a platinum plate serving as a counter electrode for 12 hours.
When applied for 0 minutes, an anodized film is formed on the resist metal layer. This oxide film has a diameter of about 300-40
A large number of vertical fine holes 22 having a thickness of 0 nm and a depth of 4 to 5 μm are formed.

Subsequently, an etching process was performed on the resist layer 20 by ECR plasma etching using carbon tetrafluoride gas as an assist gas. As a result, in the fine hole portion 22 of the resist layer, since the thickness of the resist layer is thin, the etching progresses selectively, and the fine hole 4 having a vertical shape is also formed on the surface of the lower tungsten metal body 40.
2 was formed.

After the etching is completed, the tungsten metal body 4
The resist layer 20 remaining on the surface of No. 0 was immersed in a 2N sodium hydroxide aqueous solution to dissolve the resist layer 20 made of aluminum oxide. Finally, the alumina substrate 10 was mechanically polished and dissolved and removed in hot phosphoric acid to obtain a target tungsten metal body 40 having a fine hole shape.

FIG. 3 (a) is a bar graph showing the distribution of fine holes formed on the surface of the tungsten metal body. From this figure, it was confirmed that the cross-sectional diameters of the fine holes had relatively little variation, and uniform fine holes were formed around 300 to 400 nm. On the other hand, the depth of fine holes is 3-5
It was about μm. FIG. 3 (b) shows the results of measuring the relationship between wavelength and emission intensity using the metal body manufactured as described above as a light emitter (filament) for a lamp.
For comparison, a conventional filament made of ordinary tungsten was also measured under the same conditions.

From the measurement results, the conventional filament has a much higher emission intensity in the other wavelength region, that is, in the infrared region than the emission intensity of the radiated light (700 nm or less) in the visible region. On the other hand, in the embodiment of the present invention, the portion with a wavelength of 700 nm or less shows almost the same tendency as the conventional example, but when the wavelength exceeds 700 nm, the emission intensity sharply decreases, and It is confirmed that the radiation is suppressed.

Therefore, the luminous body for a lamp obtained by the manufacturing method of the present invention emits only visible light efficiently, with almost no emission in the infrared region, which was conventionally wasted. It was confirmed that a luminous body for a lamp having extremely good luminous efficiency was obtained. -Example 2-A luminescent body for a lamp was manufactured in the same manner as in Example 1 except that molybdenum was used instead of tungsten as the material of the metal body 40.

FIG. 4 (a) shows the result of measuring the pore distribution of fine holes in the obtained lamp luminous body.
(b) shows the relationship between wavelength and emission intensity. All the measurement results show excellent results as in Example 1,
As in Example 1, a luminous body for a lamp having extremely good luminous efficiency was obtained.

[0030]

As described above, according to the method for producing a metal body having fine holes according to the present invention, the use of the anodic oxide film having fine holes as a resist for etching makes it possible to obtain a desired metal. It has become relatively easy to form holes on the surface of the body that are extremely fine, have a high aspect ratio, and have a uniform shape.

In this method, it is possible to relatively easily and efficiently form ultrafine holes which cannot be practically processed by the conventional photolithography technique using a polymer resist and other processing methods. Further, since it can be applied to the processing of a large area, it can greatly contribute to the improvement of the productivity and the reduction of the manufacturing cost in the manufacture of the metal body having the fine holes of such a shape.

Furthermore, if the manufacturing method of the present invention is applied to the manufacture of a light-emitting body for a lamp, the fine holes as described above can be easily and uniformly formed on the surface of the light-emitting body for a lamp, and the luminous efficiency is improved. It becomes possible to manufacture an extremely excellent luminous body for a lamp with high productivity and at low cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a stepwise manufacturing process of an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a manufactured metal body having fine holes.

FIG. 3 is a graph showing a distribution (a) of pore diameters and a relationship (b) between wavelength and emission intensity in specific examples.

FIG. 4 shows the distribution of pore size in another specific example.
Graphs showing (a) and the relationship between wavelength and emission intensity (b).

[Explanation of symbols]

 20 Metal Layer for Resist 22 Micro Hole 40 Metal Body 42 Micro Hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshifumi Watanabe 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (2)

[Claims] 1. A metal layer for resist is formed on the surface of a metal body for forming fine holes, and the surface of this metal layer for resist is anodized to form an anodic oxide film having many fine holes. Later, using this anodic oxide film as a resist,
A method for producing a metal body having fine holes, characterized in that fine holes are formed in the metal body by performing etching treatment thereon. 2. A method for manufacturing a lamp light-emitting body according to claim 1, wherein the lamp light-emitting body is made of a metal body having fine holes.