JP4457995B2 - Artificial quartz crystal manufacturing apparatus, artificial quartz crystal manufacturing method, and filter member - Google Patents

Description

The present invention relates to an artificial quartz crystal manufacturing apparatus, an artificial quartz crystal manufacturing method, and a filter member .

Quartz is used in large quantities in electronic devices, communication devices, optical devices and the like as a raw material for crystal devices and optical components.
This quartz crystal was originally manufactured by cutting out from natural crystal. However, in recent years, since a higher quality crystal can be efficiently manufactured, a method of manufacturing from an artificially grown artificial crystal has been used.

As one of the above methods, a hydrothermal temperature difference method (hydrothermal synthesis method) has been proposed (see, for example, Patent Document 1).
In the hydrothermal synthesis method, in the pressure vessel (chamber), the crystal raw material is dissolved in an alkaline solution at the bottom of the vessel and circulated by thermal convection, and the seed crystal fixed on the top of the vessel is brought into contact with the alkali solution, so that the seed crystal Is a method for producing an artificial quartz crystal.

  However, in the hydrothermal temperature difference method, the impurities contained in the quartz raw material or a part of the container that has deteriorated or dropped due to the alkaline solution convects with the alkaline solution as a foreign substance and adheres to the seed crystal being grown and adheres to the artificial quartz crystal. There is a problem of being captured inside. The artificial quartz containing such a foreign substance has a characteristic deteriorated, and therefore must be discarded, which is a main cause of a decrease in manufacturing yield.

In order to solve such a problem, in Patent Document 1, umbrella-shaped control members that control convection of the alkaline solution are provided at both ends of the seed crystal. Thereby, it is suppressed that a foreign material adheres to a seed crystal.
However, this control member only has a function of controlling the convection of the alkaline solution, and does not have a function of capturing foreign matter. For this reason, the foreign matter always remains in the alkaline solution, and depending on the direction of the convection of the alkaline solution, the foreign matter may adhere to the seed crystal so as to go around the control member. Thus, only by controlling the convection of the alkaline solution, it cannot be said that the effect of preventing the adhesion of foreign substances is sufficient.
Furthermore, it is necessary to provide control members individually for a large number of seed crystals, which requires great effort and cost.

JP 2001-19584 A

An object of the present invention is to provide an artificial quartz crystal manufacturing apparatus and an artificial quartz crystal manufacturing method capable of efficiently manufacturing a high quality artificial quartz crystal with a high yield, and a filter member installed in an autoclave in the manufacturing of the artificial quartz crystal. is there.

The above object is achieved by the following.
The artificial quartz crystal production apparatus of the present invention is an artificial quartz crystal production apparatus that houses a solution, a quartz crystal raw material, and a seed crystal in a pressure vessel, and produces an artificial quartz crystal by a hydrothermal synthesis method.
A filter member that is provided above the seed crystal storage region in the pressure vessel, has a plurality of through holes, and controls the flow rate of the solution;
The shielding rate of the cross section of the pressure vessel in the portion where the filter member is disposed is different between the peripheral region and the central region of the pressure vessel ,
The shielding rate in the central region is higher than the shielding rate in the peripheral region .
Thereby, an artificial quartz crystal manufacturing apparatus capable of efficiently manufacturing a high quality artificial quartz crystal with a high yield can be obtained.

In the artificial quartz crystal manufacturing apparatus of the present invention, the filter member is composed of a laminate formed by laminating a plurality of nets,
It is preferable that the shielding ratio of the cross section of the pressure vessel can be adjusted by changing the arrangement of the mesh body.
In the artificial quartz crystal manufacturing apparatus of the present invention, the degree of supersaturation of silicon oxide with respect to the solution in the region above the filter member disposed in the pressure vessel is relative to the solution in the seed crystal storage region. It is preferable that the crystal grains are generated in the solution in the upper region by providing a difference in supersaturation so as to be higher than that of silicon oxide.
As a result, since the impurities are captured and removed by the filter function of the filter member, it is possible to prevent the impurities from adhering to the seed crystal, and as a result, the impurity content is very low, that is, high purity ( High quality) artificial quartz.

In the artificial quartz crystal manufacturing apparatus of the present invention, the difference in supersaturation provides a temperature difference so that the temperature of the solution in the upper region is lower than the temperature of the solution in the seed crystal storage region. It is preferable that it is formed by this.
Thereby, crystal grains containing impurities in the solution can be more easily precipitated (generated) in the upper region.
In the artificial quartz crystal manufacturing apparatus of the present invention, the pressure vessel has a shape that is long in the vertical direction,
It is preferable to have a heating means provided along the longitudinal direction of the pressure vessel to generate thermal convection in the solution by heating the pressure vessel .
Thereby, the thermal convection of a perpendicular direction can be produced reliably in a solution.
In the artificial quartz crystal manufacturing apparatus of the present invention, the heating means can control the temperature of the solution in the seed crystal storage region and the temperature of the solution in the upper region to be different from each other. It is preferable to be configured.
Thus, the degree of supersaturation with respect to the silicon oxide solution in the crystal raw material storage region, the degree of supersaturation with respect to the silicon oxide solution in the seed crystal storage region, and the degree of supersaturation with respect to the silicon oxide solution in the upper region are as follows. , Each can be adjusted differently.

The method for producing an artificial quartz crystal of the present invention is a method for producing an artificial quartz crystal for producing an artificial quartz crystal by growing a seed crystal carried into an autoclave by a hydrothermal synthesis method,
Arranged above the seed crystal storage area in the autoclave is a filter member that has a plurality of through holes and controls the counter flow rate of the solution stored in the autoclave.
The shielding rate of the cross section of the autoclave in the portion where the filter member is disposed is different between the peripheral region and the central region of the autoclave ,
The shielding rate in the central region is higher than the shielding rate in the peripheral region,
The seed crystal is grown in the autoclave.

In the method for producing an artificial quartz crystal of the present invention, the filter member is composed of a laminate formed by laminating a plurality of nets,
  It is preferable to adjust the shielding ratio of the cross section of the autoclave by changing the arrangement of the mesh body.

The filter member of the present invention is a filter member having a plurality of through holes,
The counter flow rate of the solution stored in the autoclave is controlled by placing the seed crystal above the seed crystal storage area in the autoclave in which the seed crystal is grown by hydrothermal synthesis to produce an artificial crystal. Is,
The shielding ratio of the cross section of the autoclave in the portion to be arranged is different between the peripheral area and the central area of the autoclave ,
The shielding rate in the central region is configured to be higher than the shielding rate in the peripheral region .

The filter member of the present invention is composed of a laminate formed by laminating a plurality of nets,
  It is preferable that the shielding ratio of the cross section of the autoclave can be adjusted by changing the arrangement of the mesh body.

Hereinafter, an artificial quartz crystal manufacturing apparatus, an artificial quartz crystal manufacturing method, and a filter member according to the present invention will be described in detail with reference to the accompanying drawings.
1 is a schematic diagram (longitudinal sectional view) showing an embodiment of an artificial quartz crystal manufacturing apparatus according to the present invention, and FIG. 2 is a cross-sectional view taken along the line AA of the artificial quartz crystal manufacturing apparatus shown in FIG. FIG. 3 is a plan view showing another configuration example of the filter member. In the following, for convenience of explanation, the upper side in FIG. 1 is referred to as “upper”, the lower side is referred to as “lower”, the front side of the paper in FIGS. 2 and 3 is “upper”, and the rear side of the paper is “lower”. Say. Moreover, the dotted line in FIG. 3 respond | corresponds to the position and size of a chamber.

An artificial quartz crystal manufacturing apparatus (autoclave) 1 shown in FIG. 1 is an apparatus for manufacturing an artificial quartz crystal by a hydrothermal temperature difference method.
The artificial quartz crystal manufacturing apparatus 1 accommodates a solution 5, a crystal raw material 11, and a seed crystal 12, and is provided in a vertically long chamber 2 and an outer peripheral portion of the chamber 2, and heats the chamber 2. Thus, the heating means 9 for generating a thermal convection in the solution 5 in the chamber 2 is provided.

As shown in FIG. 1, the chamber 2 includes a bottomed cylindrical main body 2a and a lid 2b that seals the upper opening of the main body 2a.
The overall shape of the main body portion 2a is not particularly limited, but it is preferable that the side portion has a substantially cylindrical shape. Thereby, it is possible to easily and surely convect the dissolved solution 5 accommodated therein in the vertical direction. Further, as will be described later, when the inside of the chamber 2 is pressurized, excellent pressure resistance can be imparted to the chamber 2 if it is cylindrical.
In this case, the dimensions of the main body 2a are preferably about 300 to 1000 mm in inner diameter and about 5 to 20 m in height (length).

  The constituent material of the chamber 2 (the main body 2a and the lid 2b) is not particularly limited, and examples thereof include iron-based metals such as high-tensile steel and stainless steel, titanium-based metals, aluminum-based metals, and nickel-based metals. Can be mentioned. Among these, as a constituent material of the chamber 2, high-tensile steel is preferable. High tensile steel has particularly high tensile strength, and can particularly increase the pressure resistance of the chamber 2.

The pressure resistance of the chamber 2 is not particularly limited, but is preferably 50 MPa or more, and more preferably 100 MPa or more. In the hydrothermal temperature difference method, it is necessary to dissolve a larger amount of silicon oxide (quartz, SiO ₂ ) in the solution 5 by applying a high pressure in the chamber 2. Even when a high pressure is applied over a long period of months, the chamber 2 can be reliably prevented from being damaged.
Moreover, it is preferable that the inner wall of the chamber 2 (particularly, the main body 2a) is made of a material having higher corrosion resistance to the solution 5 than the inner wall of the container made of the above material. Examples of such a material include a resin material such as a fluororesin, and a noble metal material such as gold and platinum.

Inside the chamber 2, a convection control plate (baffle plate) 3 and a filter member 4 (the filter member of the present invention) above the convection control plate 3 partition the space in the chamber 2. It is provided as follows. Thereby, in the chamber 2, a first space 21 below the convection control plate 3, a second space 22 between the convection control plate 3 and the filter member 4, and a third space above the filter member 4. The space 23 is defined.

Among these spaces, the crystal material 11 is stored in the first space 21, and the seed crystal 12 is stored in the second space 22 by being fixed or suspended by a jig or the like (not shown). In general, the first space 21, the second space 22, and the third space 23 are filled with the solution 5.
Here, the quartz raw material 11 serves as a supply source for supplying silicon oxide for producing artificial quartz.
For this quartz raw material 11, for example, Lasca, which is a small piece of natural quartz, is used.
The seed crystal 12 serves as a nucleus for recrystallizing and growing the artificial crystal.
The seed crystal 12 is, for example, a crystal piece such as a bar-shaped “Y bar” elongated in the Y-axis direction or a plate-shaped “Z plate” that is long in the Y-axis direction and has a width in the X-axis direction.

The solution 5 functions as a medium for transporting silicon oxide dissolved from the crystal raw material 11 stored in the first space 21 from the first space 21 to the second space 22 or the third space 23. Is.
Examples of the solution 5 include an alkali solution such as an aqueous solution of sodium hydroxide (NaOH), an aqueous solution of sodium carbonate (Na ₂ CO ₃ ), an aqueous solution of ammonium nitrate (NH ₄ NO ₃ ), an aqueous solution of sodium nitrate (NaNO ₃ ), nitric acid An acid solution such as a calcium (Ca (NO ₃ ) ₂ ) aqueous solution may be mentioned, and an alkaline solution is preferable. Alkaline solutions have a particularly high solubility in silicon oxide, and are therefore suitable as a medium for transporting silicon oxide.

In particular, among the alkali solutions, a sodium hydroxide aqueous solution or a sodium carbonate aqueous solution is preferable. Since these alkali solutions have high chemical stability and are relatively inexpensive, they are particularly suitable as a medium for transporting silicon oxide.
When an alkaline solution is used as the solution 5, the concentration of the solute (alkaline substance) is preferably about 1 to 10 wt%, and more preferably about 2 to 5 wt%. Thereby, the maximum crystal deposition rate can be obtained while suppressing the corrosion / deterioration of the chamber 2 to the minimum.

The convection control plate 3 has a function of controlling the convective flow rate of the solution 5 that convects between the first space 21 and the second space 22.
The convection control plate 3 of the present embodiment is configured by a net-like body in which a plurality of through holes that allow the solution 5 to pass are formed. Accordingly, the dissolved solution 5 can rise from the first space 21 to the second space 22 and drop from the second space 22 to the first space 21 along with the heat convection. Thereby, a temperature difference corresponding to the counter flow rate can be formed between the first space 21 and the second space 22.
In the convection control plate 3, the convection flow rate of the solution 5 can be controlled by appropriately setting the size and number of through holes.

The aperture ratio of the through hole of the convection control plate 3 is appropriately set according to the convective flow rate of the target solution 5 and is not particularly limited, but is preferably about 3 to 50%, and about 5 to 40%. More preferably. Accordingly, the temperature difference between the upper and lower spaces (the first space 21 and the second space 22) partitioned by the convection control plate 3 by appropriately controlling the thermal convection of the solution 5 is optimally described in detail later. Within a certain range. As a result, a difference occurs in the degree of supersaturation of the silicon oxide solution 5 with respect to the solution 5 of the silicon oxide between the first space 21 and the second space 22, and it becomes possible to more reliably control the precipitation of the crystal.
As a constituent material of such a convection control plate 3, for example, the same material as the constituent material of the chamber 2 can be used.

In the third space 23, the filter member 4 captures the miscellaneous crystals (crystal grains) 10 generated in the solution 5 that is convected by heat, and the miscellaneous crystals 10 move to the second space 22. In addition to having a function of blocking, it has a function of controlling the convective flow rate of the solution 5 that convects between the second space 22 and the third space 23.
Here, the miscellaneous crystal 10 is crystallized by containing a substance that becomes an impurity for the artificial quartz crystal. Examples of the impurities include particles insoluble in the solution 5 contained in the crystal raw material 11, material components of the chamber 2 eluted by the solution 5, and the like.

In general, when crystals are precipitated from the solution 5, if there is a foreign substance that can become a nucleus, the tendency to preferentially precipitate around the foreign substance is high. Accordingly, crystal is preferentially precipitated and grown around such a foreign substance, and a miscellaneous crystal 10 is generated.
Further, the miscellaneous crystal 10 includes a by-product mineral composed of silicon and other elements, and specific examples thereof include, for example, alumite containing iron, emerysite containing lithium, and calcium. Pectolite to be used.

  Such a miscellaneous crystal 10 deteriorates characteristics required for the artificial quartz, for example, electrical and optical characteristics, and therefore is preferably excluded from the artificial quartz as much as possible. Since the miscellaneous crystal 10 (impurities) is captured and removed by the filter function of the member 4, the miscellaneous crystals 10 can be prevented from adhering to the seed crystal 12, and as a result, the impurity content is very small. That is, high-purity (good quality) artificial quartz can be manufactured.

The filter member 4 of the present embodiment is composed of a laminate formed by laminating two rectangular mesh bodies 41 and 42 so as to be orthogonal to each other, and the dissolved solution 5 is added to the second liquid due to thermal convection. It is possible to rise from the space 22 to the third space 23 and to descend from the third space 23 to the second space 22.
The filter member 4 can easily adjust the conditions such as the shielding rate of the space by the filter member 4 by changing the arrangement of the mesh bodies 41 and 42.

  Such a filter member 4 preferably has an area ratio (shielding rate) of about 50 to 90% in the cross-sectional area of the portion of the chamber 2 where the filter member 4 is located, and about 60 to 80%. Is more preferable. Accordingly, the temperature difference between the upper and lower spaces (second space 22 and third space 23) partitioned by the filter member 4 is appropriately controlled by appropriately controlling the heat convection of the dissolving solution 5, and the optimum will be described in detail later. Can be kept within range. As a result, the second space 22 and the third space 23 can form a difference in the degree of supersaturation with respect to the silicon oxide solution 5. And according to this supersaturation degree difference, in the 3rd space 23, the precipitation amount of the crystal | crystallization which preferentially precipitates can be controlled. Moreover, if the said shielding rate of the filter member 4 is in the said range, the miscellaneous crystal 10 can be capture | acquired reliably.

The volume of the third space 23 defined on the upper side by the filter member 4 is preferably about 3 to 20% of the volume of the space in the chamber 2, and more preferably about 5 to 15%. preferable. Thereby, the third space 23 having a volume sufficient for generating and capturing the miscellaneous crystals 10 can be secured while preventing the chamber 2 from being unnecessarily enlarged.
As a constituent material of such a filter member 4, the material similar to the material quoted by the chamber 2 can be used, for example.

In addition, when laminating | stacking and using a mesh body, it is preferable that the number of sheets is 2-100 sheets, and it is more preferable that it is 5-50 sheets. Thereby, the function as a filter can be surely exhibited in the filter member 4 while preventing the thermal convection of the solution 5 from being hindered.
Further, the filter member 4 may be composed of a single mesh.
Moreover, the planar view shape of the filter member 4 may be, for example, a square, a quadrangle such as a rhombus, a perfect circle, a circle such as an ellipse, or a cross, in addition to a rectangle.

Furthermore, the chamber 2 is provided with a pressurizing means (not shown). This pressurizing means pressurizes the inside of the chamber 2, and by pressurizing the inside of the chamber 2, the solubility of silicon oxide in the solution 5 can be increased. Further, the solubility of silicon oxide in the solution 5 can be changed by adjusting the pressure of pressurization.
In addition, a pressure gauge 27 and a safety valve 28 are provided in the upper portion (the lid portion 2b) of the chamber 2. By monitoring the pressure in the chamber 2 with the pressure gauge 27, the inside of the chamber 2 can be maintained at a predetermined pressure. Moreover, when the predetermined pressure is exceeded, the safety valve 28 automatically releases the pressure, thereby preventing the chamber 2 from being damaged due to unnecessary pressure.

A heating means 9 is provided on the outer periphery of the chamber 2 along the longitudinal direction thereof.
The heating means 9 includes a heater 91 provided in a portion corresponding to the first space 21, a heater 92 provided in a portion corresponding to the second space 22, and a portion corresponding to the third space 23. The heater 93 is provided.

Each heater 91-93 is attached so that it may be wound around the outer peripheral surface of the chamber 2, respectively. Thereby, the solution 5 in the first space 21, the first space 22, and the third space 23 is heated evenly in the circumferential direction of the chamber 2, and vertical convection is ensured in the solution 5. Can be generated.
With such a configuration, in the cross section of the chamber 2, the temperature of the wall (edge) is slightly higher than that of the central portion, so that the upward flow of the solution 5 mainly occurs in the central portion. Will cause a downward flow of the solution 5 respectively.

Such a heater 91-93 can be comprised with a sheathed heater etc., for example. Since this sheathed heater is a heater in which a heating wire is enclosed in a metal tube, deterioration due to oxidation or the like of the heating wire is suppressed, and continuous heating for a long period of time is possible.
Moreover, these heaters 91-93 are comprised so that an output may be controlled independently by the control means which is not shown in figure, respectively. That is, the temperature of the solution 5 in the first space 21, the temperature of the solution 5 in the second space 22, and the temperature of the solution 5 in the third space 23 can be controlled to be different from each other. It is configured. Accordingly, the degree of supersaturation with respect to the silicon oxide solution 5 in the first space 21, the degree of supersaturation with respect to the silicon oxide solution 5 in the second space 22, and the silicon oxide solution 5 in the third space 23. The degree of supersaturation with respect to can be adjusted differently.

In the present embodiment, the temperature of the solution 5 is adjusted by the heating unit 9 such that the temperature in the first space 21> the second space 22> the third space 23. By providing this temperature difference, the solubility of the silicon oxide in the solution 5 is adjusted so as to be in the first space 21> in the second space 22> in the third space 23. That is, the degree of supersaturation of the silicon oxide solution 5 with respect to the solution 5 is adjusted so that the first space 21 <the second space 22 <the third space 23.
As a result, the crystal raw material 11 is dissolved in the first space 21. Then, the dissolved solution 5 in which silicon oxide is dissolved rises along the wall portion of the chamber 2 and reaches the third space 23 through the second space 22, and falls in the central portion of the chamber 2 due to a decrease in temperature. (Ie heat convection).

Next, the operation of the artificial quartz crystal manufacturing apparatus 1 (the artificial quartz crystal manufacturing method for manufacturing the artificial quartz crystal using the artificial quartz crystal manufacturing apparatus 1) will be described.
[1] First, the crystal raw material 11 is placed in the first space 21 in the chamber 2, and the seed crystal 12 is suspended in the second space 22. Further, the convection control plate 3 and the filter member 4 are attached, and the chamber 2 is filled with a predetermined amount of the solution 5.
At this time, the solution 5 fills the chamber 2 as described above. The amount of the solution 5 (filling ratio with respect to the volume of the chamber 2) is preferably about 60 to 95%, and more preferably about 70 to 85%. Thereby, the effect of trapping the miscellaneous crystal 10 in the third space 23 is reliably exhibited.

[2] Next, the inside of the chamber 2 is pressurized.
The pressure when pressurizing the inside of the chamber 2 is preferably about 50 to 200 MPa, and more preferably about 90 to 150 MPa. When the pressure in the chamber 2 exceeds the above range, it is necessary to change the constituent material of the chamber 2 to an expensive material with higher tensile strength or to increase the thickness of the chamber 2 in order to increase the pressure resistance of the chamber 2. This leads to an increase in manufacturing costs. On the other hand, when the pressure in the chamber 2 is lower than the above range, the solubility of the silicon oxide in the solution 5 is lowered, and the deposition rate of crystal may be lowered.

[3] Next, the heaters 91, 92, and 93 are controlled to heat the first space 21, the second space 22, and the third space 23, respectively. Thereby, the inside of the chamber 2 becomes a high temperature / high pressure state, and the solubility of the silicon oxide in the solution 5 increases. As a result, a large amount of silicon oxide in the crystal raw material 11 is dissolved in the solution 5.
When heating, it is preferable to heat so that the temperature of each solution 5 in the first space 21, the second space 22, and the third space 23 in the chamber 2 is different.

  Specifically, the heaters 91, 92, and 93 are respectively controlled so that the temperature of the solution 5 in the second space 22 is lower than the temperature of the solution 5 in the first space 21, and the second space 22. It is preferable to heat so that the temperature of the solution 5 in the third space 23 is lower than the temperature of the solution 5 therein. Thereby, a temperature difference arises in the chamber 2, and a constant flow arises in the solution 5 by the heat convection accompanying this temperature difference.

  That is, only by providing such a temperature difference, the degree of supersaturation with respect to the silicon oxide solution 5 in the third space 23 is made higher than the degree of supersaturation with respect to the silicon oxide solution 5 in the second space 22. be able to. Thereby, the miscellaneous crystals (crystal grains) 10 containing impurities in the solution 5 can be more easily precipitated (generated) in the third space 23. As described above, the precipitated miscellaneous crystals 10 are captured and stored in the third space 23 by the filter member 4. As a result, the miscellaneous crystal 10 is prevented from adhering to the seed crystal 12 in the second space 22, and a high-quality artificial crystal with high purity can be obtained.

  As a specific temperature difference, the temperature of the solution 5 in the second space 22 is preferably set to be about 20 to 60 ° C. lower than the temperature of the solution 5 in the first space 21. It is more preferable to set the temperature to be about -50 ° C lower. Thereby, an appropriate thermal convection and supersaturation difference occur between the first space 21 and the second space 22, and the deposition rate of the crystal deposited on the surface of the seed crystal 12 is optimized. As a result, an artificial quartz crystal can be manufactured in a shorter growing period.

The temperature of the solution 5 in the third space 23 is preferably set to be about 10 to 40 ° C. lower than the temperature of the solution 5 in the second space 22 and is about 15 to 30 ° C. lower. More preferably, it is set as follows. As a result, an appropriate thermal convection and supersaturation difference occur between the second space 22 and the third space 23, and the miscellaneous crystal 10 is surely precipitated in the third space 23. The deposition rate of the quartz crystal in the space 22 can be made faster (efficient deposition).
When such a temperature difference is provided, the temperature of the solution 5 in the first space 21 is preferably about 360 to 410 ° C., and the temperature of the solution 5 in the second space 22 is preferably About 320-360 degreeC, The temperature of the solution 5 in the 3rd space 23 is preferably about 300-340 degreeC.

[4] The crystal is continuously deposited and grown on the surface of the seed crystal 12 by leaving it in the state of the step [3] for a predetermined period.
The standing period (growth period) varies depending on the size of the artificial quartz required and the deposition rate of the quartz, but is preferably about 1 to 6 months.
An artificial quartz is obtained as described above.

In the method for manufacturing artificial quartz crystal as described above, for example, step [2] and step [3] can be performed simultaneously or in the reverse order. Moreover, you may make it add arbitrary processes.
According to the present invention as described above, a high-quality artificial quartz with high purity and few crystal defects can be efficiently manufactured with a high yield.
The obtained artificial quartz is suitably used as a raw material for various devices such as crystal oscillators, crystal resonators, crystal devices such as crystal filters, optical devices such as optical filters, and surface acoustic wave elements such as SAW filters. Used.

Now, the filter member 4 may be of the structure shown in FIG. 2, for example, the structure shown in FIG.
The filter member 4 shown in FIG. 3A is configured by a laminated body in which a plurality of mesh-like bodies having a disk shape with an outer diameter slightly smaller than the inner diameter of the chamber 2 are stacked. Each of these nets is provided with a large number of through holes almost entirely. The through holes have different arrangement densities at the central portion and the peripheral portion of the filter member 4. Thereby, the resistance of the solution 5 that passes through the filter member 4 can be adjusted, and the heat flow rate at the center portion and the peripheral portion in the cross-sectional direction of the chamber 2 can be controlled.
Here, as described above, in the chamber 2, the convection direction of the solution 5 is generally different between the central portion and the peripheral portion in the cross section. Therefore, as described above, by varying the arrangement density of the through holes between the central portion and the peripheral portion of the filter member 4, it is possible to control each heat flow rate of the upward flow and the downward flow.

  On the other hand, the filter member 4 shown in FIG. 3B is configured by a laminated body in which the upper mesh body 41 is laminated in a state of being rotated by 45 ° with respect to the lower mesh body 42. Each of these nets 41 and 42 is also provided with a large number of through-holes so that the solution 5 can pass through the filter member 4. Further, a gap is generated between the filter member 4 and the inner wall of the chamber 2. With this gap and the filter member 4, it is possible to adjust the resistance to the flow of the solution 5 that is about to pass through the filter member 4. Thereby, a difference in the counter flow rate of the solution 5 can be provided between the central portion and the peripheral portion of the filter member 4.

In addition, in the portion where the mesh body 41 and the mesh body 42 overlap, the size of the through hole can be changed according to the overlapping method. Thereby, the size (particle diameter) of the miscellaneous crystal 10 filtered by the filter member 41 can also be adjusted.
As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to this.
For example, each part constituting the artificial quartz crystal manufacturing apparatus of the present invention can be replaced with any one that exhibits the same function, or other configurations can be added.

Next, specific examples of the present invention will be described.
1. Production of artificial quartz (Example)
An artificial quartz crystal was manufactured using the artificial quartz crystal manufacturing apparatus shown in FIGS. The conditions at the time of production are shown below.
Chamber dimensions: 650mm inner diameter x 14m height
Chamber material: High tensile steel Pressure in the chamber: 130 MPa
Solution composition: Sodium hydroxide aqueous solution Solution concentration: 4 wt%
Solution filling rate: 85%
Type of seed crystal: Z plate Opening ratio of convection control plate: 10%
Filter member shielding rate: 70%
Number of filter member nets: 50 Temperature of solution in first space: 390 ° C.
Temperature of the solution in the second space: 350 ° C
Temperature of the solution in the third space: 335 ° C
Growth period: 3 months Number of artificial quartz produced: 1500 (comparative example)
An artificial quartz crystal was produced in the same manner as in the above example except that an artificial quartz crystal manufacturing apparatus in which the filter member was omitted was used.

2. Evaluation For each of the 1500 artificial quartz crystals obtained in the examples and comparative examples, the density of foreign substances contained in the artificial quartz was evaluated. This evaluation was performed in accordance with the test method and evaluation criteria specified in JIS C 6704. Table 1 shows the evaluation criteria.

Moreover, as an evaluation item, it was set as the non-defective rate which made the artificial quartz which satisfies the class I at least among the five grades shown in Table 1 into a non-defective product. Then, the yield rate was evaluated according to the following criteria.
A: Good product rate of 90% or more ○: Good product rate of 75% or more and less than 90% Δ: Good product rate of 60% or more and less than 75% X: Good product rate of less than 60% Table 2 shows the evaluation results.

As is apparent from Table 2, the yield rate of the artificial quartz obtained in the examples was a very high yield of 90% or more (◎). In addition, in the grade breakdown (occupation rate by grade) of non-defective products, the highest quality grade Ia occupies a high ratio of 40%, and in the example, an extremely high quality artificial quartz crystal could be obtained with a high yield.
On the other hand, the yield rate of artificial quartz obtained in the comparative example was 60 or more and less than 75% (Δ). In the breakdown of non-defective products, Grade I accounted for a relatively high proportion of just under 20%, and the overall foreign matter density was slightly higher.
From the above, it has become clear that according to the artificial quartz crystal manufacturing apparatus and artificial quartz crystal manufacturing method of the present invention, high-quality artificial quartz can be efficiently manufactured with high yield.

It is the schematic (longitudinal sectional view) which shows embodiment of the manufacturing apparatus of the artificial quartz crystal of this invention. It is the sectional view on the AA line of the artificial quartz crystal manufacturing apparatus shown in FIG. It is a top view which shows the other structural example of a filter member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Artificial crystal manufacturing apparatus 2 ... Chamber 2a ... Main part 2b ... Cover part 3 ... Convection control board 4 ... Filter member 5 ... Dissolved solution 10 ... Miscellaneous crystals 11 ... Crystal raw material 12 ... ... Seed crystal 21 ... First space 22 ... Second space 23 ... Third space 27 ... Pressure gauge 28 ... Safety valve 41, 42 ... Reticulated body 9 ... Heating means 91, 92, 93 ……heater

Claims (10)

An artificial quartz crystal manufacturing apparatus that stores a dissolving liquid, a crystal raw material, and a seed crystal in a pressure vessel and manufactures an artificial crystal by a hydrothermal synthesis method,
A filter member that is provided above the seed crystal storage region in the pressure vessel, has a plurality of through holes, and controls the flow rate of the solution;
The shielding rate of the cross section of the pressure vessel in the portion where the filter member is disposed is different between the peripheral region and the central region of the pressure vessel ,
The artificial quartz crystal manufacturing apparatus , wherein a shielding rate in the central region is higher than a shielding rate in the peripheral region . The filter member is composed of a laminate formed by laminating a plurality of nets,
By changing the arrangement of the mesh body, artificial crystal manufacturing apparatus according shielding ratio of the cross-section of the pressure vessel to claim 1 is adjustable. The supersaturation of the silicon oxide with respect to the solution in the region above the filter member disposed in the pressure vessel is higher than the supersaturation of silicon oxide with respect to the solution in the seed crystal storage region. 3. The artificial quartz crystal manufacturing apparatus according to claim 1, wherein the crystal grains are generated in the solution in the upper region by providing a degree difference. 4. The supersaturation difference is formed by providing a temperature difference so that the temperature of the solution in the upper region is lower than the temperature of the solution in the seed crystal storage region. 3. The artificial quartz crystal manufacturing apparatus according to 3. The pressure vessel has a vertically long shape,
Wherein provided along the longitudinal direction of the pressure vessel, artificial crystal manufacturing apparatus according to any one of claims 1 to 4 having a heating means for generating heat convection to the solution by heating the pressure vessel . It said heating means, the temperature of the solution of the solution temperature and the upper in the region of the seed crystal accommodating region, according to claim 5 which is configured to be controlled differently each Artificial quartz manufacturing equipment. An artificial quartz crystal manufacturing method for producing artificial quartz by growing seed crystals carried into an autoclave by a hydrothermal synthesis method,
Arranged above the seed crystal storage area in the autoclave is a filter member that has a plurality of through holes and controls the counter flow rate of the solution stored in the autoclave.
The shielding rate of the cross section of the autoclave in the portion where the filter member is disposed is different between the peripheral region and the central region of the autoclave ,
The shielding rate in the central region is higher than the shielding rate in the peripheral region,
A method for producing artificial quartz crystal, wherein the seed crystal is grown in the autoclave. The filter member is composed of a laminate formed by laminating a plurality of nets,
The method for manufacturing an artificial quartz crystal according to claim 7 , wherein a shielding rate of a cross section of the autoclave is adjusted by changing the arrangement of the mesh body. A filter member having a plurality of through holes,
The counter flow rate of the solution stored in the autoclave is controlled by placing the seed crystal above the seed crystal storage area in the autoclave in which the seed crystal is grown by hydrothermal synthesis to produce an artificial crystal. Is,
The shielding ratio of the cross section of the autoclave in the portion to be arranged is different between the peripheral area and the central area of the autoclave ,
The filter member characterized by making the shielding rate in the said center area | region higher than the shielding rate in the said peripheral area | region . It is composed of a laminate formed by laminating a plurality of nets,
The filter member according to claim 9 , wherein the shielding ratio of the cross section of the autoclave can be adjusted by changing the arrangement of the mesh body.

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