JPH0135798B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing crystals, and when artificially manufacturing crystals, materials such as those that require ultra-high temperature and high pressure conditions, such as diamond, are used. The present invention provides a method for manufacturing gemstones, metal crystals, etc. at low cost.

Structure and Problems of Conventional Example In the crystal manufacturing method using an outer packaging material and a laser, which the present inventor previously proposed in Japanese Patent Application No. 57-63744, as shown in FIG. 2 is sealed in a sphere of transparent material (such as quartz or glass), and irradiated with a laser beam 3 focused from the outside to mainly heat and melt the crystal raw material 1, which is the core, and after cooling. In this method, the higher the temperature of the crystal raw material 1, the greater the radiant energy emitted from the crystal raw material as heat rays 4. In other words, there was a drawback that energy loss was large.

For example, when producing diamond, if a catalyst is not used, conditions of about 300,000 atm and 3,000 〓 are required, but if 10 g of graphite is used as the crystal raw material, a YAG laser with a power of about 10 KW is required. And so. This becomes 3000〓,
This is because the thermal radiation is as high as 460W/cm ² . In other words, most of the laser irradiation was wasted as radiant heat emitted from the crystal raw material.

Purpose of the Invention In view of the drawbacks of the previously proposed methods described above, the purpose of the present invention is to reduce the energy loss due to radiation during heating of the crystalline raw material and to melt the crystalline raw material with high efficiency using a low-power laser. The purpose is to

Structure of the Invention The present invention is a method for manufacturing an artificial crystal, in which a sphere made of a crystal raw material and an optically transparent outer envelope material surrounding the crystal raw material is prepared in advance.
The crystal raw material is surrounded by a concave mirror with windows at predetermined intervals, and by irradiating laser light from the window, the heated rays emitted as radiant heat from the heated crystal raw material are focused again by the concave mirror, and the crystal raw material is The present invention is characterized in that the surface of the outer envelope material and the concave mirror are prevented from increasing in temperature by irradiating the mirror, and more preferably by flowing a cooling gas into the gap between the concave mirror and the outer envelope material.

DESCRIPTION OF EMBODIMENTS An example will be described in detail below with reference to FIG. In advance, a sphere encapsulated with an outer packaging material 2 made of a transparent material such as glass so as to surround the crystal raw material 1 is wrapped with a concave mirror 6 provided with windows 5 at predetermined intervals, and a laser beam 3 is irradiated through the windows 5. Then, the core crystal raw material was heated and melted. At this time, as the temperature of the crystal raw material 1 increases, the radiant heat emitted to the outside of the sphere as heat rays 4 is mostly reflected inward by the concave mirror and is again focused on the crystal raw material. Therefore, when the method of the present invention is used, there is almost no energy loss emitted to the outside of the sphere, so the power of the laser beam can be significantly reduced. Next, when the laser beam irradiation is stopped and the material is cooled, the raw material is slowly cooled at high temperature and pressure, and diamond crystals are formed. In addition, at this time, the outer packaging material hardly absorbs the heat rays, and the temperature rises mainly due to heat conduction due to contact with the heated crystal raw material, and in the case of a short time (several seconds), the outer surface The temperature did not rise at all. Also, since the concave mirror reflects most of the heat rays, the temperature did not rise much. If long-term laser irradiation is required, the surface of the outer envelope material and the concave mirror will inevitably rise in temperature, so in that case, by flowing cooling gas into the gap between the outer envelope material and the concave mirror, It was possible to prevent temperature rise.

For example, when manufacturing diamonds, conditions of about 300,000 atm and 3,000 m are required without using a catalyst. It was coated with Pyrix 7740 manufactured by Glass Co., Ltd., and the whole was heated to melt and harden the glass powder serving as the outer packaging material, thereby forming a transparent glass sphere with graphite as the core inside. Alternatively, graphite may be inserted into molten glass in advance and slowly cooled to harden. At this time, the diameter of the graphite core was approximately 2 cm, so the diameter of the outer envelope made of transparent glass was set to 20 cm or more. Next, we cover this sphere with a concave mirror, and when we irradiate a YAG laser with a power of 1 to 2 KW through the window, the graphite heats up to 3000 degrees Celsius in a few tens of milliseconds to a few hundred milliseconds.
It became more than that and was melted. At this time, the outer packaging material is made of glass, which has poor thermal conductivity, and no thermal expansion occurs on the outside of the sphere for about a few seconds, resulting in the graphite being held at high temperature and high pressure. Moreover, the glass of the outer package was not damaged. This is because the glass diameter is 20 cm or more ((approximately 10 times)) compared to the graphite diameter of 2 cm, so even if the internal pressure is 500,000 atm, the pressure applied to the glass surface is
It is about 5000 atmospheres, and the Young's modulus of glass is 6 to 8×
Considering 10 ³ Kg/cm ² , it can be seen that the glass was not destroyed. After that, the laser irradiation was stopped and the sphere was allowed to stand, and the sphere was cooled from the outside, and the molten crystal raw material was cooled while being held at high pressure, resulting in diamond powder crystals with a particle size of about 1 μm. Here, the generation of diamond was confirmed by the fact that the sapphire substrate was scratched when pressed and rubbed against the surface-polished sapphire substrate.

Although this embodiment shows the laser beam 3 being irradiated from two directions, it is clear that the laser beam 3 may be irradiated from one direction or a large number of laser beams may be irradiated. .

Effects of the Invention By using the method of the present invention, energy loss in crystal production can be significantly reduced, so the laser can be downsized and energy efficiency can be improved. Further, even if it is necessary to increase the laser irradiation time, the surface of the outer packaging material and the concave mirror can be easily cooled.

[Brief explanation of drawings]

Figure 1 is a schematic diagram for explaining the crystal manufacturing method using a laser previously proposed by the present inventor;
The figure is a schematic cross-sectional configuration diagram for explaining a crystal manufacturing method using a windowed concave mirror according to an embodiment of the present invention. 1...Crystal raw material, 2...Outer envelope material, 3...
Laser, 4...heat ray, 5...window, 6...concave mirror.

Claims (1)

[Scope of Claims] 1. A sphere made of a crystal raw material and an optically transparent outer covering material surrounding the crystal raw material is surrounded by a concave mirror provided with windows at predetermined intervals, and a laser beam and a laser beam incident through the windows are surrounded. A crystal manufacturing method comprising: heating, melting, and cooling the crystal raw material by condensing the reflected light of the laser beam from the concave mirror on the outer packaging material and irradiating the crystal material. 2. The crystal manufacturing method according to claim 1, characterized in that cooling gas is caused to flow through the gap between the concave mirror and the outer packaging material.