JPH0529154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a coaxial discharge type metal vapor laser oscillation device, in particular a laser tube consisting of a jacket tube and a plasma discharge tube inserted inside the jacket tube. The present invention relates to a metal vapor laser oscillation device, such as a copper vapor laser oscillation device, in which a heat insulating material layer is provided between the mantle tube and the plasma discharge tube so as to surround the plasma discharge tube.

(Prior art and its problems) Among metal lasers, copper vapor lasers are excellent with many features such as high output, high efficiency, high gain, and high repeatability, and are well matched with dye lasers. It is attracting attention for its uranium enrichment by atomic and laser methods. This type of coaxial discharge type oscillator is also attracting attention in other medical and processing fields, but since the plasma discharge tube is heated to a high temperature of over 1500 degrees Celsius, the plasma discharge tube itself is subjected to thermal shock. It goes without saying that the plasma discharge tube should be made of a material that is resistant to heat, but sufficient consideration must also be given to the insulation and heat retention of the plasma discharge tube.

However, the conventional heat insulating material layer for insulating the plasma discharge tube is made by disposing cotton-like ceramic fibers so as to cover the entire length of the plasma discharge tube. The plasma discharge tube was supported at both ends by ring electrodes on both sides. However, when the inside of the plasma discharge tube reaches a high temperature of over 1500 degrees Celsius during use, the plasma discharge tube becomes easily deformed, although the middle part of the plasma discharge tube is supported by ceramic fibers. Since the ceramic fiber itself is very soft, it could not be supported by it, and eventually it was deformed into a downward curved shape by the actual weight.
Additionally, since both ends of the plasma discharge tube are in contact with the electrodes, the heat of the plasma discharge tube, which is heated to high temperatures during use, escapes to the outside through the electrodes. Both ends of the discharge tube were lower in temperature than the center, and a drawback was that uniform metal vapor could not be obtained.

(Technical means for solving the problems) In view of the above-mentioned problems, the present invention has been developed to replace the ceramic fibers that were conventionally used as insulation materials, and to have both functions as insulation materials and structural materials. At least a heat insulating material layer is formed by a roughly donut-shaped ceramic piece formed from a ceramic board, eliminating the need to support the plasma discharge tube with electrodes on both sides, thereby preventing the heating of the plasma discharge tube during use. The purpose is to prevent curved deformation and to obtain a uniform temperature distribution over the entire length of this plasma discharge tube. A technical means for achieving this purpose is that the heat insulating material layers 6, 6 are formed by densely filling a large number of approximately donut-shaped ceramic pieces 14 within the support tube 12 made of ceramics over the entire length of the support tube 12; The supporting tube 12 is made up of a plurality of similar ceramic pieces 14 loaded at required locations with ceramic fibers interposed between them, and a plasma discharge is applied to the ceramic pieces 14 so as to pass through the cavities 13 of the ceramic pieces 14. The tube 3 is fitted and supported, and ring electrodes 15, 15 on both sides disposed coaxially with the discharge tube 3 have a cylindrical portion 15a that protrudes in mutually opposing directions. It is characterized in that the tip end is inserted into both ends of the plasma discharge tube 3 in a non-contact manner.

As the ceramic board forming the donut-shaped ceramic piece, it is preferable to use, for example, Saphial Alumina Board (SALI) manufactured by Zilker. Moreover, the donut shape is a cylindrical shape with a hole in the center, and is not limited to the so-called donut shape.

(Example) Examples of the present invention will be described below based on the drawings.

Figure 1 shows a copper vapor laser oscillation device in a longitudinal section, and in this figure 1 is a laser tube;
A cylindrical mantle tube 2, a plasma discharge tube 3 inserted concentrically into the mantle tube 2, and a mantle tube 2.
End plates 5, 5 are airtightly connected to both ends of the cylinder via connecting cylindrical members 4, 4. Reference numeral 6 denotes a cylindrical heat insulating layer provided in the laser tube 1 so as to surround the plasma discharge tube 3, and a middle tube 7a is provided between the outer peripheral surface of the heat insulating material layer 6 and the inner peripheral surface of the outer tube 2. are interposed concentrically, and a water-cooled chamber 7b is formed on the outside of this inner tube 7a, and a vacuum insulation chamber 7c is formed inside thereof in an annular shape.
Further, an annular water cooling chamber 4a is also formed on the outside of each connecting cylindrical member 4.

The mantle tube 2 is made of glass with high strength and low coefficient of thermal expansion. The plasma discharge tube 3 is
It is composed of a cylindrical outer tube part 8 formed of alumina-based fine ceramics, and a cylindrical inner tube part 9 that is slidably fitted into the outer tube part 8. The section 9 is composed of a plurality of divided bodies 9a divided at required intervals in the axial direction, and each divided body 9a is made of boron nitride [BN (boron nitland)], which is a type of fine ceramics. Consists of sintered body. Further, as clearly shown in FIG. 2, at both left and right ends of each divided body 9a, there are engaging step portions 10 that can be engaged with opposing ends of other divided bodies 9a in a radially overlapping state. ,1
1 is formed, and therefore, each divided body 9a is slidably and removably inserted into the outer tube part 8 with the opposing engaging step parts 10 and 11 engaged with each other. ing. As shown in FIG. 2, in the space S between the outer circumferential surface of the inner tube section 9 and the inner circumferential surface of the outer tube section 8 formed by the divided bodies 9a...
Powder of a sintered body of boron nitride is inserted when each divided body 9a is fitted.

The heat insulating material layer 6 includes a cylindrical support tube 12 made of alumina-based fine ceramics arranged concentrically with the plasma discharge tube 3, and a cylindrical support tube 12 made of alumina-based fine ceramics that is placed in close contact with the entire length of the support tube 12. A large number of approximately donut-shaped ceramic pieces 14...
The plasma discharge tube 3 is fitted and supported so as to be inserted into the cylindrical cavity portion 13 of each of these approximately donut-shaped ceramic piece groups 14. Furthermore, among the group of approximately donut-shaped ceramic pieces 14 fitted into the support tube 12, several ceramic pieces 14' on both end sides have slightly smaller hole diameters, and these ceramic pieces 14' This prevents the plasma discharge tube 3 from coming off. A pair of ring electrodes 15 are disposed on both sides of the plasma discharge tube 3 coaxially with the discharge tube 3, and are composed of a cylindrical portion 15a and an outward flange portion 15b connected to one end thereof. The cylindrical portions 15a, 15a are fixed to the cylindrical member 4 at the flange portions 15b, respectively, with the cylindrical portions 15a facing each other. and each ring electrode 15
The cylindrical part 15a is inserted into the small diameter cavity 13' of the ceramic piece 14', and the inner tube part 9 is inserted into the inner tube part 9 with its tip part not touching the plasma discharge tube 3 as shown in FIG. There is a slight protrusion at the end. Both ends of the support tube 12 are connected and fixed to the connecting cylindrical members 4, 4. Each of the donut-shaped ceramic pieces 14, 14' is made of SALI alumina board (SALI) manufactured by Zilker, and has excellent heat insulation properties.

As shown in FIG. 2, a large number of recesses 16 consisting of spiral grooves are formed on the inner circumferential surface of each divided body 9a constituting the inner tube portion 9 of the plasma discharge tube 3. A copper piece P for generating copper vapor is locked in any of the recesses 16.

To briefly explain the method of assembling the main parts of the copper vapor laser oscillation device described above, first, the connecting cylindrical members 4, 4 are attached to both ends of the outer tube 2 and the support tube 12 inserted therein, respectively. Approximately donut-shaped ceramic pieces 14 are disposed within the support tube 12.
After fitting the previously assembled plasma discharge tube 3 into a series of cavities 13 continuously formed by sequentially fitting the support tubes 12
Approximately donut-shaped ceramic pieces 14' with a small hole diameter were fitted into both ends of the plasma discharge tube 3 in the inside, thereby forming a cylindrical heat insulating material layer 6 and at the same time holding and fixing the plasma discharge tube 3 inside this heat insulating material layer 6. state. Thereafter, the cylindrical portions 15a of the ring electrodes 15, 15 are inserted into the hollow portions 13' at both ends of the heat insulating material layer 6, and the end plates 5, 5 are attached to the communicating cylindrical members 4, 4. Before inserting the plasma discharge tube 3 into the cavity 13, a copper piece P is inserted into the recess 16 of the divided body 9a of the inner tube 9 of the plasma discharge tube 3. By engaging in the recess 16 in this manner, the copper piece P will not move undesirably and will be held in a fixed position. In addition, to disassemble this device, the above operations can be performed in the reverse order. In addition, in Figure 1, 17
17b is a vacuum port, 18a is a cooling water supply port, 18b is a cooling water discharge port, 19 is a vacuum port, and 20a is a cooling port. Water supply port, 2
0b is a cooling water outlet.

In the copper vapor laser oscillation device of this embodiment, the plasma discharge tube 3 is surrounded and supported over its entire length by a heat insulating layer made of a large number of doughnut-shaped ceramic pieces 14. Even if the inside of the discharge tube 3 reaches a high temperature of 1500 degrees Celsius or higher, the plasma discharge tube 3 itself will not be deformed into a curved shape. The plasma discharge tube 3 has an outer tube part 8 and an inner tube part 9 made of fine ceramics, and the inner tube part 9 is made of a sintered body of boron nitride, which is particularly resistant to thermal shock. Therefore, even if the inside of the plasma discharge tube 3 reaches a high temperature of 1,500 degrees Celsius or higher, it will not be damaged by thermal shock, and in the unlikely event that such a high temperature suddenly occurs, a part of the inner tube section 9 will be damaged. However, since the inner tube portion 9 is made up of a plurality of divided bodies 9a, it is only necessary to replace some of the divided bodies, which is extremely economical. In addition, boron nitride is not only resistant to thermal shock but also has good workability, making it easy to manufacture. Since a large number of recesses 16 are provided on the inner peripheral surface of each divided body 9a, the copper piece can be held in a predetermined position via the recesses 16.

In the embodiment shown in FIG.
The heat insulating material layer 6 was formed by continuously fitting a large number of donut-shaped ceramic pieces 14 into the entire longitudinal direction of the heat insulating material layer 6. However, as in the embodiment shown in FIG. Donut-shaped ceramic piece 14
, in pieces only at required locations within the support tube 12, for example, as shown in the same figure, two locations on the center side and one on the end side.
It is also possible to load the parts one by one. However, in the case of such a piecemeal arrangement, cotton-like ceramic fibers 21 are loaded between the doughnut-shaped ceramic pieces 14 and further on the end sides. In this case, the heat insulating layer 6' is composed of the ceramic pieces 14, the ceramic fibers 21, and the support tube 12. In this case, the ceramic fiber 21 disposed toward the center may be shaped so that the diameter of the center is gradually smaller than that of both ends, as shown in the figure. Further, the ring electrodes 15 on both sides are disposed such that the tips of the cylindrical portions 15a protrude into both ends of the plasma discharge tube 3 in a non-contact manner, as in the embodiment shown in FIG. In this embodiment as well, since a plurality of locations of the plasma discharge tube 3 are supported by the doughnut-shaped ceramic pieces 14, it is possible to sufficiently prevent the discharge tube 3 from being bent due to high temperature heating. In FIG. 3, the same members as those in the embodiment shown in FIG. 1 are designated by the same reference numerals.

(Effects of the Invention) According to the present invention, the plasma discharge tube can be supported by the approximately donut-shaped ceramic piece that has both the function of a heat insulating material and the function of a structural material. It is possible to prevent curved deformation of the discharge tube, and
The ceramic pieces that are closely arranged or the ceramic pieces that are arranged piecemeal and the ceramic fibers interposed between them can fully demonstrate their original insulation function as a heat insulating layer, and can maintain the high temperature state inside the plasma discharge tube. It is possible to prevent the outer tube from becoming too hot.

In addition, as a coaxial discharge type, a pair of ring electrodes coaxially arranged on both sides of the plasma discharge tube partially protrude into the end of the discharge tube in a non-contact manner, so that the discharge In addition to being carried out only inside the plasma discharge tube, the high heat of this plasma discharge tube does not escape to the outside, resulting in a uniform temperature distribution over the entire length of the plasma discharge tube, resulting in extremely high excitation efficiency and stable excitation. Laser oscillation can be obtained.

Furthermore, when assembling the heat insulating material layer, all that is needed is to fit the donut-shaped ceramic pieces into the support tube one after another, making the work very simple and even when the length of the plasma discharge tube is changed. There is an advantage that the length of the heat insulating layer can be easily adjusted according to the length of the plasma discharge tube by increasing or decreasing the number of ceramic pieces.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a metal vapor laser oscillation device according to the present invention, and FIG. 2 is a partially enlarged vertical cross-sectional view of a plasma discharge tube in the same device.
FIG. 3 is a longitudinal sectional view showing another embodiment. DESCRIPTION OF SYMBOLS 1... Laser tube, 2... Outer tube, 3... Plasma discharge tube, 6, 6'... Heat insulating material layer, 8... Outer tube part of plasma discharge tube, 9... Inner tube part, 9a... Division body, 10, 1
DESCRIPTION OF SYMBOLS 1... Engagement step part (engaging part), 12... Support pipe, 13...
Hollow portion, 14...approximately donut-shaped ceramic piece, 1
5... Ring electrode, 15a... Cylindrical part, 16... Concave part, 21
...ceramic fiber, P...copper piece.

[Claims]

1 (A) 30 to 90% by weight of liquid crystal polyester, (B) 3 to 50% by weight of inorganic fibrous or acicular material having an average diameter of 15 μm or less and an average length of 200 μm or less, and (C) alkaline earth. A resin composition for a printed wiring board comprising 3 to 30% by weight of a similar metal carbonate.

Claims (1)

The plasma discharge tube is fitted and supported so that the ring electrodes on both sides have cylindrical portions protruding in mutually opposing directions, and the tips of the cylindrical portions are fitted into both ends of the plasma discharge tube. A gas laser oscillation device characterized by being immersed in a non-contact state.