JPS60221386A - Manufacturing apparatus of single crystal by infrared-condensing heating - Google Patents

Abstract

PURPOSE:To grow automatically and stably a crystal for many hours by providing a filter and a diaphragm to an optical system in the titled apparatus for automatically controlling by the observation of an image of the melt zone from the port of a spheroidal mirror. CONSTITUTION:The image of a melt zone is focused on an optical sensor from the port provided at a part of a spheroidal mirror through an optical system consisting of a lens, a prism, a half mirror, a reflector, etc., and the diameter or the external shape of the melt zone is fed back to the lamp power or the height of the melt zone to control automatically in the titled apparatus. In the apparatus, the optical system is constituted of a melt zone 41, a filter 42, a lens 43 (including a prism), a diaphragm 44, an optical sensor 45, and a front panel 46. When the luminance of the melt zone is changed because the required power is varied in accordance with the kind of materials of the crystal, the change can be coped with by the exchange of filters and the opening degree of the diaphragm. Consequently, the crystal can be stably grown for many hours (>=10hr).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an Fz apparatus (infrared concentrated heating single crystal manufacturing apparatus), and particularly to an F2 apparatus that automatically grows crystals.

[Prior art]

Conventionally, crystal synthesis in an Fz apparatus has not been automatically controlled, and only images from a hole provided at one location of a spheroidal mirror are observed on a screen.

Therefore, in order to grow crystals, it was necessary to constantly monitor images and manually adjust the lamp power or gap.

〔the purpose〕

The present invention is intended to solve the above problems, and its purpose is to provide an FZ apparatus that can stably grow crystals for a long time (10 hours or more).

〔overview〕

The FZ device of the present invention includes lenses, prisms, and half mirrors.
1. A filter and a diaphragm are provided in the middle of an optical system such as a reflecting mirror, and an image of the molten zone is formed on an optical sensor through the optical system through a hole provided in a part of the spheroidal mirror. This system automatically grows crystals by processing signals from an optical sensor, and is characterized by a high signal-to-noise ratio of the signal from the optical sensor and high control accuracy.

Figure 1 is the old one? An overview of the Z-wave device is shown.

Here, 1 is a spheroidal mirror, 2 is a halogen lamp #8 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 12 is a screen.

The raw material rod 6 is set on the upper shaft 9, and the lower shaft 1
Set seed crystal 7 to 0. .

The power of the halogen lamp 2 is turned on, 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 through the gas inlet 4 and exhausted through 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 upper shaft 9 and the lower shaft 10 are rotated in the same direction or in opposite directions, and the upper and lower shafts simultaneously move downward.

The state of the light condensing section is projected onto the screen 12 via the lens 11 (including the prism) and the reflecting mirror, and the distance (gap) between the lamp buff or raw material rod and the seed crystal is adjusted while constantly monitoring the projected image. Crystal growth is performed while making adjustments.

FIG. 2 shows an overview of the optical system of the previous FZ device.

Here, (, z) is a plan view, and (b) is a side view.

21 is a melting zone, 22 is a lens (including a prism), 28 is a reflecting mirror, 24 is a screen, and 25 is a front panel.

FIG. 8 shows a block diagram of an automatic control system used in the FZ device of the present invention.

Here, 31 is an optical system, 32 is a sensor section, 38 is a controller section, 84 is a key power section, 85 is a DA converter, 36 is an AD converter, 37 is a display section, 88 is a printer part, 39
4 is a lamp power control section, and 40 is a gap adjustment section.

The image of the melted zone passes through the optical system 31 and reaches the sensor section 32, where the control section 89 adjusts the lamp power to control the temperature of the melted zone, or the gap adjustment section 40 adjusts the height of the melt. Adjust.

The lamp power or gap is fed back to the controller section 88 via the AD converter 36.

On the other hand, the key input section 84 inputs various initial constants, and the display section 87 displays the lamp power and the like at that time. Furthermore, the printer part 88 prints out the lamp power, melting zone diameter, melting zone height, etc. at predetermined intervals.

When performing automatic control, the S of the signal at the optical sensor
The N ratio has an extremely large influence on subsequent calculation processing,
A high signal-to-noise ratio is an essential condition.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIGS. 4 and 5 show plan views of the optical system of the apparatus of the present invention.

Here, 41 and 51 are melting zones, 42 and 52 are filters, 43 and 58 are lenses (including prisms), and 44 and 5
4 is an aperture, 45 and 55 are optical sensors, 46 and 56 are front panels, 5'lt is a nauf mirror, 58 is a reflector, and 59 is a screen.

1 In Figure 6, a line sensor is used as an optical sensor,
This shows the signal waveform measured by an oscilloscope when performing arithmetic processing.

Here, 61 is the direct value of the light level of the sensor, and 62
is the value obtained by binarizing this.

(α) is the correct value when the aperture is set too far, (b) is the appropriate value, and (C
) is the case when the aperture is opened too much.

If the aperture (α) is narrowed down too much, the binarized signal will be cut off in the middle as shown in
If the aperture in C) is opened too much, the direct value of the amount of light increases at the ends like Y, making the determination of both ends of the diameter inaccurate.

Since the required power differs depending on the crystal material, the brightness of the molten zone changes, but in the present invention, it is possible to replace the filter and
This can be handled by changing the opening/closing status of the throttle.

〔effect〕

As described above, according to the present invention, even if the material of the crystal changes, an appropriate signal level can be obtained and the crystal can be grown stably for a long time.

Therefore, not only single crystals for gemstones such as ruby, sapphire, alexa/dried, etc., but also YAG, YAG, GGG, etc.
It can also be used for industrial single crystals such as
High-quality single crystals without defects can be grown.

[Brief explanation of drawings]

FIG. 1 shows an outline of a conventional FZ device. FIG. 2 shows an outline of the optical system of a conventional FZ device. FIG. 3 shows a block diagram of an automatic control system used in the FZ device of the present invention. FIG. 4 shows an outline of the optical system of the FZ device of the present invention. FIG. 5 shows an outline of another optical system of the FZ device of the present invention. FIG. 6 shows signal waveforms when a line sensor is used in the FZ device of the present invention. Figure 1 (Kyu) (1) Figure 2 Figure 3 α-9' = Q”-”” ” Figure 5

Claims (1)

[Claims] An image of the molten zone is formed on an optical sensor through a hole provided in a part of the spheroidal mirror, through an optical system such as a lens, prism, and half mirror 1 reflector, and the diameter or external shape of the molten zone is measured. , an infrared condensed heating single crystal manufacturing apparatus that performs automatic control by feeding back the lamp power or the height of the melting zone, characterized in that the optical system is provided with a filter and an aperture. Device.