JPH0647014Y2 - Image heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to improvement of an image heating light source of an image furnace used for crystal growth of semiconductor materials and the like.

[Conventional technology]

FIG. 4 is a sectional view showing the configuration of a conventional image heating apparatus shown in, for example, “Solid State Physics” Vol.14, No.10, 1979, pages 633 to 640, in which (1) shows the inner surface. An ellipsoidal mirror with a spheroid polished and plated with gold, (2) a light source such as a halogen lamp or a xenon lamp installed at the first focal point of the ellipsoidal mirror (1), and (3) connected to this light source. A power source, (4) a sample as a sample placed on the second focal point of the elliptical mirror (1), and (5) a quartz tube accommodating the sample (4).

The conventional image heating device is configured as described above, and the light emitted from the light source (2) is focused on the second focus, and the temperature of the material rod (4) rises. The quartz tube (5) is provided for controlling the atmosphere by evacuating the inside or injecting gas.

[Problems to be solved by the device]

In the conventional image heating device as described above, the light source (2) is a halogen lamp or Xe lamp, and the size of the light emitting part is as small as 5 to 7 mm in diameter, so the temperature gradient on the surface of the material rod (4) is large, There were problems such as cracking.

Furthermore, the life of halogen and Xe lamps is 100 hours and 1500, respectively.
There was a problem that it took a lot of time and money to replace it because it was short.

In addition, the lamp startup and restart times are 180 seconds and 3 seconds, respectively.
It took about 00 seconds and was very inconvenient in the heating process. In other words, there is a problem in that it is difficult to control the temperature accurately if the startup time is long when cooling to a certain temperature after heating and performing the annealing treatment at this temperature.

The present invention has been made to solve such a problem. By adopting an egg-shaped microwave discharge lamp as a light source, the temperature gradient can be made gentle, the life can be extended, and image heating that can start and restart quickly can be performed. The purpose is to obtain the device.

Further, another embodiment of the present invention uses a light source in addition to the above objects.
The purpose is to make the sample uniform and the temperature of the sample uniform.

[Means for Solving the Problems]

In the image heating device according to the present invention, a wire mesh is placed inside an elliptical mirror, and a plasma lamp in a space, that is, a cavity resonator formed between the wire mesh and the elliptic mirror is placed, and an electric wave is injected to form an egg-shaped plasma. It makes the lamp emit light.

In another embodiment of the present invention, two elliptical mirrors are combined to form a bi-elliptical mirror, an egg-shaped plasma lamp is placed at each first focus, and the temperature distribution of the sample placed at the second focus is made uniform. To do.

[Action]

In this invention, when the egg-shaped plasma lamp placed at the first focus is excited by radio waves and emits light, the light transmitted through the wire mesh is spherically focused by the elliptical mirror and collected on the sample placed at the second focus. Light and heat the sample.

In another embodiment of the present invention, the light of an egg-shaped plasma lamp placed at each of the first focus of the first elliptical mirror and the first focus of the second elliptical mirror is made into a common second focus. The sample is heated by focusing on the placed sample.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention,
(1) and (4) are exactly the same as the above conventional device. In (6), the thick part of the first focus is directed toward the second focus,
This is an egg-shaped plasma lamp whose center is placed at the first focal point. Elements such as Xe and K are enclosed in ceramic or glass hollow spheres. Reference numeral (7) is a supporting member for supporting the egg-shaped plasma lamp (6), which is made of heat conductive ceramics such as aluminum nitride. (8) is a radio wave shield plate that is made of a disc-shaped wire mesh attached to the end of the elliptical mirror (1) and shields radio waves. Conduction is maintained and constitutes a cavity resonator (9). (11) is a cavity resonator (9)
A rectangular hole (10) is made in a part of the waveguide, and a waveguide is attached with the opening end aligned with this hole (10). (12) is a magnetron attached to the end of this waveguide (11). (A klystron is also acceptable.) And (13) are power supplies connected to the magnetron (12).

In the image heating apparatus configured as described above, electric power is supplied from the power source (13) to oscillate the magnetron (12) to inject a radio wave into the waveguide (11), and the cavity resonator is inserted from the hole (10). Electromagnetic energy is injected into (9) and absorbed by the egg-shaped plasma lamp (6). The egg-shaped plasma lamp (6) emits light when excited by plasma by electromagnetic waves, passes through the radio wave shielding plate (8), is condensed by the elliptical mirror (1), and heats the sample (4) placed at the second focal point. .

At this time, the light of the egg-shaped plasma lamp (6) forms an image around the sample (4), but the image is formed by the reflection of the elliptical surface, which causes distortion. This distortion occurs so that the second focal side portion of the egg-shaped lamp (6) placed at the first focal point becomes elongated, so if the light emitting source is deformed into an oval shape in advance to correct this distortion, The image of the focal point is close to a sphere.

In the above embodiment, the disc-shaped wire mesh (8) is attached to the inside of the elliptic mirror (1), but the radio wave shielding plate (8) is formed into a cup shape with a sloped U-shape. Even if it is attached to the end portion on the first focal point side, the same operation can be performed.

FIG. 2 shows a cup-shaped radio wave shield (8) with an elliptical mirror (1).
FIG. 6 shows another embodiment when mounted on the oval plasma lamp (6) placed at the first focal point of the elliptical mirror (1).
A cup-type radio wave shielding plate (8) is attached to house the housing, and the cavity resonance condition can be determined by the shape of the radio wave shielding plate (8), which is not affected by the shape of the elliptical mirror (1). Occurs.

As described above, in the embodiment of the present invention, a cavity resonator is constructed by attaching a radio wave shield plate including a first focus to the inside and the end of an elliptical mirror, and an egg-shaped plasma lamp is placed in this cavity to emit light. , The sample placed on the second focus is heated, but since the diameter of the egg-shaped plasma lamp is large, for example, 10 to 30 mm, the image formed on the sample is large, and due to the spherical shape, the entire sample of the sample has an extremely average intensity. It has the effect of making the temperature of the sample hitting the surface uniform.

This is a very important effect in material manufacturing in microgravity in space. This is because if the heat distribution on the surface of the sample is non-uniform, Marangoni convection will occur and disturb the crystal growth of the material, eliminating the effect of microgravity, and it is necessary to heat the sample at a temperature as uniform as possible. .

Furthermore, since the egg-shaped plasma lamp does not use a filament and has a long life and is robust, it is extremely easy to handle and has a long life and simple maintenance as compared with the conventional image heating apparatus using a halogen lamp.

Now, in this invention, the egg-shaped plasma lamp (6) and the shielding plate (8) are attached to the first focal point of the elliptic mirror (1) as described above, but as shown in another embodiment of FIG. The second elliptic mirror (14) is attached in the long axis direction of the elliptic mirror (1) so that the second focal point is shared, and the egg-shaped plasma lamp (6) and the support are attached to the end of the second elliptic mirror (14). (7) and the radio wave shielding plate (8) are attached to form the cavity resonator (9). The light emitted by both egg-shaped plasma lamps (6) is focused on the sample (4) placed in the second focus and heats it. Since the sample (4) is irradiated with light in all directions, a uniform temperature distribution is obtained. Further, the same effect can be obtained even if the radio wave shielding plate (8) is cup-shaped.

[Effect of device]

As described above, the present invention constructs a cavity resonator in which an electromagnetic wave shielding plate including a first focus is provided inside an elliptic mirror, and an egg-shaped plasma lamp is placed in the cavity resonator to emit light, thereby forming a second focus. Since I tried to heat the placed sample,
Since the image formed on the sample is large and spherical, the sample can be heated at a uniform temperature. In addition, the plasma lamp is excited by radio waves to emit light, and since it does not use a filament, it has a long life and is easy to handle as compared with a conventional image heating apparatus using a halogen lamp.

Further, in another embodiment of the present invention, two egg-shaped plasma lamps are used to heat the sample from both, so that the heat distribution of the sample can be made more uniform.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the present invention, FIG. 3 is a sectional view showing still another embodiment, and FIG. It is sectional drawing which shows the image heating apparatus of FIG. In the figure, (1) is the first elliptic mirror, (2) is the light source,
(3) is a power source, (4) is a sample, (5) is a quartz tube,
(6) is an egg-shaped plasma lamp, (7) is a support, (8)
Is a radio wave shield, (9) is a cavity resonator, (10) is a hole,
(11) is a waveguide, (12) is a magnetron, (13) is a power supply, and (14) is a second elliptical mirror. The same reference numerals in each figure indicate the same or corresponding parts.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location H01S 3/093 8934-4M H05B 3/00 345 7913-3K 6/80 9032-3K

Claims (2)

[Scope of utility model registration request] 1. An ellipsoidal mirror having a spheroidal reflecting surface inside, an oval plasma lamp placed at a first focal point of the ellipsoidal mirror, and a support for supporting the oval plasma lamp. A radio wave shield provided inside the elliptic mirror and provided on the side of the first focal point of the elliptic mirror, and an empty space formed by the radio wave shield and the elliptic mirror for housing the egg-shaped plasma lamp. An image heating apparatus comprising: a body resonator; and driving means for driving the plasma lamp to emit light. 2. A first elliptical mirror having a spheroidal reflecting surface inside and a second ellipse that shares a second focal point of the first elliptic mirror.
Elliptical mirrors, egg-shaped plasma lamps placed at the first focal points of both, a support for supporting these oval-shaped plasma lamps, and an elliptical mirror inside the both elliptic mirrors, respectively. A radio wave shield provided on the side of the first focal point of the elliptical mirror, a cavity resonator formed of the radio wave shield and both of the elliptical mirrors, and housing the egg-shaped plasma lamps, respectively, and the plasma. An image heating apparatus comprising: a driving unit for driving a lamp to emit light.