JPS6121992A - Device for preparation single crystal heated with convergent infrared ray - Google Patents

Abstract

PURPOSE:The titled device capable of executing stable crystal growth for a long period, prevention of power loss, and elongation of lamp life by constructing a part of elliposidal mirror of revolution for converging light emitted from a halogen lamp variably from reflection state to nonreflection state. CONSTITUTION:The light emitted from a light source such as a halogen lamp at high temp. is converged by an ellipsoidal mirror of revolution 51 to form a melting zone between a starting material bar and seed crystal in a light converging part, and the melting zone is moved at a fixed speed, and a single crystal deposited on the seed crystal in a floating zone is a device for prepg. a single crystal heated with a convergent infrared rays. In this device, a reflection preventing plate 53 is fastened with screws together with a substrate plate 52 enabling to change a part of the ellipsoidal morror of revolution 51 from the reflecting state to the nonreflecting state. By this method, the light signal from a grown crystal is separated from stray light, and crystal growth is achieved stably for a long period. Focussing of the lamp is facilitated simultaneously, and power loss is avoided and the life of the lamp is elongated.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an infrared condensed heating single crystal production device (hereinafter abbreviated as a YZ wave device), and particularly to an apparatus for automatically controlling crystal growth. This paper relates to improvements to two devices.

[Prior art]

Conventionally, automatic control has hardly been performed in YZ devices, and only manufacturing methods using optical sensors such as line sensors or ELI sensors have been proposed.

In this case, in order to separate the original signal from the grown crystal from background stray light, it is a necessary condition that a part of the spheroidal mirror be in a non-reflecting state.

However, in this case, the focus of the lamp is not clearly determined, resulting in problems of power loss and lamp life.

〔the purpose〕

The present invention is intended to solve the above problems, and its purpose is to stably grow crystals for a long time (10 hours or more), and at the same time, to easily focus the lamp.
The purpose is to prevent power loss and extend the life of the lamp.

〔overview〕

'1 of the present invention! The z device uses optical sensors such as line sensors or factory sensors to measure the diameter, height, and temperature of the melted zone.
It measures the external shape, etc., and feeds this back to the lamp head or the height of the molten zone.

Figure 1 shows the conventional? An overview of the two devices is shown below.

Here, 1 is a spheroidal mirror, 2 is a logen lamp, 5 is a quartz tube, 4 is a gas inlet, 5 is a gas outlet, 6 is a raw material rod, 7 is a seed crystal, 8 is a molten zone, and 9 is an upper part 10 is a lower shaft, 11 is a lens (including a prism and a filter), and 12 is a screen.

The raw material rod 6 is set on the upper shaft 9, and the seed crystal 7 is set on the lower shaft 10.

The power of the halogen lamp 2 is increased, and the spheroidal mirror 1 focuses the light from the halogen lamp onto the center of the quartz tube 3. At this time, atmospheric gas is introduced from the gas inlet 4 and exhausted from the gas exhaust port 5.

In the light condensing section, the tip of the raw material rod 6 and the tip of the seed crystal 7 are brought into molten contact to form a molten zone 8. At this time, the king shaft 9 and the lower shaft 10 are rotated in the same direction or in opposite directions, and the upper and lower shafts move downward at the same time, so that crystals are grown and an image is projected onto the screen 12 through the lens 11. Control the lamp power and adjust the gap while observing the

FIG. 2 shows a block diagram of the automatic control system of the present invention.

Here, 21 is an optical system, 22 is a sensor section, 23 is an AD converter, 24 is a controller section, 25 is a display section, 26 is a key manual section, 27 is a printer part, 28 is a gap adjustment section,
29 is a DA converter, and 30 is a lamp power control section.

The image of the melted zone passes through the optical system 21, reaches the sensor section 22, passes through the AD converter 23, and is processed by the controller section 24. The processed signal passes through a DA converter 29, and a lamp power control section 30 adjusts the lamp power to control the temperature of the melting zone. Or gap adjustment part 2
Adjust the height of the melt in step 8.

Adjust the brightness.

The partial key human power section 26 inputs various constants every 1,000 degrees, and thereafter makes changes as needed. Display section 25
displays the lamp power, measured diameter, etc. at that time, and the printer part 27 prints out the lamp power, measured diameter, height of the molten zone, etc. at predetermined intervals.

When automatically controlling crystal growth, it is a necessary condition that a part of the spheroidal mirror be in a non-reflecting state.

That is, as shown in FIG. 5, which shows an example of an image on the screen, in the conventional TZ apparatus, the raw material rod 31. Growing crystal 32, melting 1
fis 3, a filament image 34 of the lamp is observed, and the signal of the melting zone is not sufficiently obtained. Therefore, in order to eliminate the filament image of the lamp, an anti-reflection plate 43 is placed inside the spheroidal mirror 41 at a position approximately symmetrical to the lens 45 with the quartz tube 44 in the center. It is set up.

This anti-reflection plate 43 eliminates the image of the halogen lamp 42 and obtains the signal level of the molten zone.

However, making the focal point of a halogen lamp valley is an important condition from the point of view of energy saving and lamp life, and improvement measures are desired. Explain in detail.

[Example 1] The reflection state is the same as the conventional FZ device, but a spheroidal mirror (gold-plated surface) is used, and an anti-reflection plate is provided on top of it.

FIG. 5 shows a plan view of the rotating circular mirror.

Here, 51 is a spheroidal mirror, 52 is a base substrate, and 53 is an antireflection plate.

The anti-reflection plate needs to be made of a black material with as low reflectance as possible. For example, the anti-reflection plate is made of iron-based material and given a black dyed or black enamel finish.

Another method is to make an anti-reflection plate from a metal material and thermally spray black ceramic onto its surface, or insert a substrate with carbon paste baked onto the ceramic surface.

Examples include a method in which the antireflection plate is directly made of black ceramic or graphite.

In both of these, screw holes are provided in the spheroidal mirror, and the base substrate and antireflection plate are screwed together.

[Example 2] A method in which substrates are prepared in both a reflective state and a non-reflective state, and either one is set at the rear of a spheroidal mirror.

FIG. 6 shows a front view of the spheroidal mirror.

Thus, 61 is a spheroidal mirror, and 62 is a substrate.

The substrate 62 is inserted from the side into a pre-provided groove.

The substrate in the reflective state is made of the same material and has the same surface finish as the spheroidal mirror, and the same material as in Example 1 is used in the non-reflective state.

〔effect〕

As described above, according to the present invention, it is possible to easily make the surface of the spheroidal mirror reflective and non-reflective, and stable crystal growth for a long time in the non-reflective state is possible. .

Furthermore, since the reflective state can be easily obtained, focusing is facilitated when replacing the lamp, which has a great effect on extending the life of the lamp and preventing power loss.

Therefore, not only single crystals for gemstones such as ruby, sapphire, and alexandrite, but also YAG, YAG, etc.

It also has the effect of greatly contributing to the growth of industrial single crystals such as GGG.

[Brief explanation of the drawing]

FIG. 1 shows the main features of a conventional FZ device. FIG. 2 shows a block diagram of the automatic control system of the present invention. FIG. 5 is a diagram showing an example of an image on the screen. FIG. 4 shows a plan view of the spheroidal mirror. FIG. 5 shows a plan view of a spheroidal mirror showing an embodiment of the present invention. FIG. 6 shows a front view of a spheroidal mirror showing an embodiment of the present invention. Figure 1 m-'' Figure 2 Figure 3 Parrot Figure 4

Claims (1)

[Claims] Light emitted from a high-temperature light source such as a halogen lamp is focused using a reflecting mirror or lens, and in the focusing section, the raw material rod and the seed crystal are combined via the molten zone to create a floating zone. In an infrared condensed heating single crystal manufacturing apparatus that deposits crystals on the seed crystal by forming a floating zone and moving the floating zone at a constant speed,
An infrared condensed heating single crystal production device characterized in that a part of a spheroidal mirror can be changed between a reflective state and a non-reflective state.