Single crystal sapphire seed crystal, method for manufacturing sapphire single crystal having desired crystal orientation, and outer component or functional component for portable watch and jewel

Abstract

To obtain a sapphire single crystal having less defects and easily machined.SOLUTION: In a method for manufacturing a sapphire single crystal, a single crystal sapphire seed crystal 1 has a rhombohedral system crystal structure defining three crystal axes [A], [C] and [M] perpendicular to each other and perpendicular to crystal planes A(11-20), C(0001) and M(10-10), respectively; the single crystal sapphire seed crystal 1 is a plate 2 having a boundary formed of two flat surfaces 4 parallel to each other and separately extended; and the single crystal sapphire plate 2 is obtained by cutting the initial sapphire single crystal so that any of the crystal axis [A], [C] or [M] of the single crystal sapphire plate 2 forms the normal D1 of the flat surface 4 of the single crystal sapphire plate 2 and an angle (α) of 5-85°.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a single crystal sapphire seed having a desired crystal orientation. The present invention further provides a method for growing single crystal sapphire having a desired crystal orientation from such a single crystal sapphire seed crystal. The present invention further relates to a method for producing a sapphire single crystal. External parts or components for watches (e.g. wristwatches, pocket watches) and jewellery cut from crystals relates to functional parts. [Background technology]

[0002] So-called single crystal materials are composed of a single macroscopic crystal with a size of 1 mm to several meters. One of the most common uses for single crystals is in jewelry. Jewelry made of stones uses single crystals such as rubies, sapphires, and diamonds. However, they are often not well known but are in the cutting edge of technology. Single crystals are still indispensable in semiconductors, used in electronics and some solar cells. Because silicon, which is used in many solid-state lasers, and the compounds used in many solid-state lasers are single crystals, From simple laser pointers to aircraft turbines, optical instruments, and power sources for nuclear fusion. - Single crystal materials have a wide range of applications, being used everywhere from semiconductors to lasers.

[0003] When a compound is in single crystal form, it has specific optical properties such as transparency and birefringence. Alumina Al2O3 crystals are transparent when they are highly pure, and are used in the watch manufacturing industry. Alumina Al2O3 crystals are often used in the manufacture of crystals for portable watches. It is used as a precious stone by coloring it with vanadium or impurities. The academic environment is completely defined and organized with the same units repeated, so The number of available sites for dopants introduced into the environment is very small, The dopants can give the single crystal very unique properties. For example, When doping a material to create a laser source, the dopant is distributed only to limited sites. Therefore, the change in energy emitted during the electronic transition of the dopant is small. By using the same technique, precise laser emission can be obtained. The presence of such dopants is important because the sites that they can occupy are specifically defined. It is possible to change the inherent properties. For example, Cr in alumina crystals +3 The presence of ions Therefore, the red color of ruby ​​is produced and the same Cr +3 Beryl containing ions (Be e Al2Si6O 18 ) turns green and is called an emerald.

[0004] For this reason, the presence of defects in the form of dopants in single crystal compounds is a technical problem. However, uncontrolled impurities, dislocations, and fractures can occur. Structural defects are undesirable. For this reason, it is generally recommended to use the highest quality single-piece construction possible. It is preferable to use crystals. It is possible to find single crystals in nature, but generally Because of this, numerous synthesis techniques have been developed since the early 20th century. There are several methods for obtaining artificial single crystals, as follows: - Obtained from a supersaturated solution of the compound. - Obtained from molten compounds. Obtained by chemical vapor deposition.

[0005] Here, the crystallization in the molten state accounts for nearly 80% of the artificial single crystals produced. This article focuses on the synthesis of single crystals of compounds that can be crystallized in the molten state. It is largely due to the Frenchman Auguste Verneuil. The method was first developed in 1891 when Verneuil was considering the synthesis of rubies for making jewellery. proposed in 2000, in which a part of a single crystal, called a seed crystal, was placed in a molten material. The chemical formula for ruby ​​and sapphire is Al2O3 To synthesize corundum, an oxygen-hydrogen torch (H 2+O2→H2O) to reach very high temperatures (melting point: 2050°C). Finely powdered alumina (sometimes doped) is used to The molten alumina droplets thus formed are then dropped in small amounts directly into the torch flame by a The mixture falls onto the top of the seed crystal and crystallizes according to the crystal structure of the seed crystal. To crystallize, the growing single crystal is gradually lowered. At the end of the synthesis, the shape of the bottle is A single crystal with this structure is obtained.

[0006] The Verneuil process is still used today in much the same form, particularly for the production of corundum for jewellery and watches. It is used for the industrial production of gemstones (rubies, sapphires, watch crystals, etc.). The Verneuil method produces more defects in single crystals than other methods, but it is relatively cheap and rapid. This method has the advantage that it is possible to obtain single crystals in about 10 hours. However, the sapphire single crystals obtained by the Verneuil method have a high dislocation density. In addition, it is difficult to control local misalignment. If the defect is in a Verneuil single crystal, it can cause a defect in the finished product, such as a crystal for a portable watch. Sometimes you can see it with your eyes.

[0007] The present invention relates to a method for synthesizing single crystals by crystallization in a molten state in a crucible. In particular, the present invention focuses on the EFG type, HEM type, Kyropoulos type, Czochralski type, Bridgman Vertical type, Bridgman Horizontal type and Micro P We are focusing on pulling-down type single crystal growth technology.

[0008] The Czochralski process, proposed by J. Czochralski in 1915, is a process in which the This is a typical method for crystallizing single crystals. The Czochralski method uses the same principle as the Verneuil method. The crystal growth process is carried out by melting a material and contacting it with a previously obtained single crystal seed crystal. The Verneuil method is based on the idea that the melting material is gradually added in small amounts. The difference is that the entire amount is added at the start of the experiment and melted, rather than being added at the beginning of the experiment. In a crucible made of a material that is resistant to high temperatures, such as platinum or iridium, The material to be melted is placed in the crucible. The crucible is placed in the center of a conductive coil through which high-frequency current flows. The crucible is heated by induction. Once the material is melted and the temperature is stable, it is pre-heated on a refractory rod. The obtained single crystal seed is placed in contact with the molten material. The seed crystal is slowly pulled towards the region to crystallize the molten material in contact with the seed crystal. In this way, the single crystal is pulled up from the molten material to obtain a single crystal. Continuous rotation homogenizes the layer of molten material that is to be crystallized.

[0009] In the Czochralski process, a temperature very close to the melting point of the material to be crystallized, but not too high. Temperature control is required because the temperature needs to be set to a low level. However, it is difficult to carry out the Czochralski method. However, the quality of the crystals produced is high, and from this point of view, the Czochralski method is a proven crystal growth technique. It is a technique.

[0010] Sapphire, whose chemical composition is Al2O3, has many uses thanks to its excellent physical properties. Sapphire is the second hardest and most durable material after diamond, making it suitable for use in mobile phones. It can be used in the watch industry and in fields where high performance is required. Synthetic sapphire is inert, transparent when polished, and acid-resistant. It has low electrical conductivity and a melting point above 2000°C, making it suitable for highly demanding applications. Fire is nearly indestructible and can withstand virtually any external attack. The crystals and technical components of watches made by IA are scratch-resistant and have a non-toxic surface. It is shiny in the holes and can be polished to perfect transparency.

[0011] As described above, the method of synthesizing single crystals by crystallizing in a molten state in a crucible is However, such a method is not feasible. To obtain the desired crystal quality, the growth rate must generally be slow, and the growth rate must be slow, e.g. in a crucible. It requires a lot of tools and is complicated, which makes it expensive. Therefore, the Czochralski method It can take more than a week to grow a single crystal by this method. It is desirable to produce defect-free single crystals.

[0012] The crystal for the portable watch is machined from a blank cut from a single crystal of sapphire. However, up until now, it has been made by crystallizing it in a molten state in a crucible. Single crystal sapphire is oriented along one of the major crystal axes of sapphire, typically [A] or [M]. These have been obtained by growing single crystal sapphire along the direction corresponding to Currently, the crystal growth mode is such that the normal to the surface is the crystal axis [A] or [M] and the crystal is bound to this surface. The blank is made so that the crystal axis [C] is included. It has been found that the blank becomes brittle and fragments are more likely to occur during the process. Therefore, the processing of the crystals for portable watches becomes difficult, the scrap rate becomes high, and This would significantly increase the cost of the windshield. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention provides a method for producing a sapphire single crystal with few defects and easy processing. The above and other problems are overcome by providing a method for producing a fire single crystal. The purpose is to comply with the [Means for solving the problem]

[0014] As a preamble, the single crystal sapphire seed crystals discussed below are The sapphire crystals are cut from single crystal sapphire and grown using the single crystal sapphire as a seed. This is then used to create a second sapphire single crystal, which is then cut to produce the desired windshield. It is important to understand that the blanks are formed.

[0015] To this end, the present invention relates to a method for producing a seed crystal of single crystal sapphire, The seed crystal of fire has a rhombohedral crystal structure that defines three crystal axes [A], [C] and [M]. The three crystal axes [A], [C] and [M] are perpendicular to each other, and are perpendicular to the crystal planes A(11-20), C(0001) and M(10-10), respectively. The seed crystal of Oia is bounded by two flat faces that run parallel to and away from each other. The single crystal sapphire plate is a plate formed by Any of the crystal axes [A], [C] or [M] of the single crystal sapphire plate is The initial sapphire single crystal is cut so that it forms an angle of 5 to 85 degrees with the normal of the flat surface. This is obtained.

[0016] In a particular embodiment, the present invention further provides a method for producing a single crystal sapphire seed. Regarding the method, the seed crystal of the single crystal sapphire has three crystal axes [A], [C] and [M]. The three crystal axes [A], [C] and [M] are mutually perpendicular to each other. , and the rhombohedral crystal planes A(11-20), C(0001) and M(10- 10) perpendicular to the crystal axis [A], [C] or [M] of the seed crystal of the single crystal sapphire. Either of the above is at an angle within the range of 5 to 85 degrees with respect to the normal of the cross section of the resulting single crystal sapphire bar. The initial sapphire single crystal is cut into a bar to form a desired shape.

[0017] In another specific embodiment, the present invention further provides a method for producing a sapphire single crystal. 6, 18B), alumina and / or sapphire are melted in a crucible and the molten alumina is Lumina and / or sapphire are bonded to a single crystal sapphire seed crystal in the form of a plate or bar. The molten alumina and / or sapphire are gradually crystallized along the growth direction by contacting the forming a single crystal sapphire.

[0018] In another particular embodiment, the present invention further comprises a method for producing a crystallized molten material in the upper part of the mold. The present invention relates to a method for producing a sapphire single crystal obtained by: Sapphire is melted in a crucible and the molten alumina and / or sapphire is poured into the channel of a die. The molten alumina and / or sapphire are then contacted with a previously obtained single crystal sapphire seed crystal through a sintering tube. Alternatively, sapphire may be gradually crystallized along the growth direction to form a single crystal of sapphire. The single crystal sapphire seed crystal has three crystal axes [A], [C] and [M The three crystal axes [A], [C] and [M] are The crystal planes A(11-20), C(0001) and M(0001) are perpendicular to each other and have a rhombohedral structure. (10-10) perpendicular to the (10-10) plane, and the single crystal sapphire seeds extend parallel to and apart from each other. a first plate bounded by two flat faces, the crystal axis [ Any of [A], [C] or [M] is the flat surface of the first single crystal sapphire plate. the first single crystal sapphire plate is aligned with the channel of the die. The angle is in the range of 5 to 85 degrees from the perpendicular direction to the flat surface determined by the above. The sapphire single crystals obtained by the crystal growth are parallel to each other and extend at a distance. A second single crystal sapphire plate is bounded by two flat surfaces that are adjacent to the In the second single crystal sapphire plate, the crystal axis [A], [M] or [C ] is the first plane of the die relative to the channel with respect to the normal of the flat surface. There is a misalignment corresponding to the tilt of the

[0019] A particular embodiment of the method according to the invention has the following features: - the crystal axis [A], [M] or [C] is the flatness of the single crystal sapphire plate The surface forms an angle within a range of 25 to 35° with the normal line of the surface. - the crystal axis [A], [M] or [C] is the flatness of the single crystal sapphire plate The surface forms an angle within a range of 5 to 15° with the normal line of the surface. - the crystal axis [A], [M] or [C] is a normal to a cross section of the single crystal sapphire bar; , forming an angle in the range of 25 to 35°. - the crystal axis [A], [M] or [C] is a normal to a cross section of the single crystal sapphire bar; , forming an angle in the range of 5 to 15°. The method for producing the sapphire single crystal is the EFG method, the HEM method, the Kyropoulos method, the Czoc method, Hralski method, Bridgman Vertical method, Bridgman Horizontal method and Micro Pulling Down method A method selected from the following is used. The fused alumina and / or sapphire may be pure or doped. - Use scrap sapphire. - after obtaining said sapphire single crystal, outer parts or functional parts for a watch or jewellery are Parts are cut from the sapphire single crystal. - said external or functional parts are bridges, plates, crystals, cases, faces of watch-type watches; It is a disc or wristlet link.

[0020] In another specific embodiment, the present invention provides a method for producing a single crystal sapphire cylinder. The method includes cutting the crystal axis [A], [M], or [C] using a cutting tool. For a sapphire single crystal ball grown along The core drilling step is performed along a direction that forms an angle with the crystal axis in the range of 5 to 85 degrees. It is equipped with

[0021] The present invention further relates to a rhombohedral crystal structure which defines three crystal axes [A], [C] and [M]. Regarding a single crystal sapphire seed crystal having a structure, the three crystal axes [A], [C] and [M ] are perpendicular to each other and correspond to the crystal faces A(11-20) and C(0001) of the rhombohedral structure, respectively. and perpendicular to M(10-10), and the single crystal sapphire seeds are parallel and spaced apart from each other. A plate bounded by two flat surfaces extending along the length of said single crystal substrate. Any of the crystal axes [A], [C] or [M] of the fire plate is the same as that of the single crystal sapphire. It forms an angle in the range of 5 to 85 degrees with the normal to the flat surface of the fire plate.

[0022] The present invention further provides a single crystal sapphire crystal that defines three crystal axes [A], [C] and [M]. Regarding the seed crystal, the three crystal axes [A], [C] and [M] are perpendicular to each other, and are perpendicular to the crystal planes A(11-20), C(0001) and M(10-10), respectively, The sapphire seed crystal is a single crystal sapphire bar, and the single crystal sapphire bar Any of the crystal axes [A], [C] or [M] is a normal to the cross section of the single crystal sapphire bar. , forming an angle in the range of 5 to 85°.

[0023] The present invention further relates to a portable device bounded by two surfaces extending away from each other. At least one of the two faces is flat. The blank has a rhombohedral structure defining three crystal axes [A], [C] and [M]. The three crystal axes [A], [C] and [M] are mutually orthogonal to each other. and perpendicular to the crystal planes A(11-20), C(0001) and M(10-10), respectively. and the crystal axis [C] is not included in the flat surface of the blank. Any of the crystal axes [A], [C] or [M] is a normal to the flat surface of the blank and is 5 to 8 Forms an angle within a range of 5°.

[0024] Finally, the present invention relates to a sapphire single crystal cut out from the sapphire single crystal obtained according to the method of the present invention. , external or functional parts for watches and jewellery, in particular bridges for watches; This relates to the plate, crystal, case, dial, or wristlet link.

[0025] Due to these characteristics, the present invention makes it possible to manufacture a crystal for a portable watch in an easily processable state. In particular, the present invention provides a method for producing a watch which allows the production of a watch-type watch-type watch-type watch-type watch-type watch. The windshield is cut from a single crystal of sapphire, which is then cut into a plate or was obtained by growing the crystal in contact with a bar-shaped single crystal sapphire seed. The seed crystal is aligned along the crystallographic axis [A], [C] or [D] of the single crystal sapphire plate or bar. M] is in the range of 5 to 85° from the normal to the flat surface of the plate or the normal to the cross section of the bar. The sapphire obtained by carrying out the method of the present invention is processed to form an angle within the range. The blank for the crystal of a portable watch cut from a single crystal is aligned along the crystal axes [A] and [C]. or [M] is the sapphire from which the blank was cut, relative to the normal of its surface. Orientation of one of the crystal axes [A], [C] or [M] of the sapphire seed crystal from which the single crystal was grown As a result, the seeding of the crystal growth of the sapphire single crystal is The flat surface of the single crystal sapphire plate or the normal to the cross section of the single crystal sapphire bar is Due to the angular deviation of the crystal axis [A], [C] or [M] with respect to one another, the crystal axis [C] is Generally, this crystal axis is not included within the flat plane of the blank of the watch crystal. [C] is a mechanical defect that usually occurs at the point across the edge of a blank for a watch crystal. This largely avoids the greatest vulnerability to processing. The blank of the windshield has a low hardness, which makes it easy to process. The blank for the crystal of the portable watch is not easily broken, so the edge of the blank may chip during processing. The risk of this is significantly reduced. In this case, dislocations in single crystal sapphire and localized and uncontrolled orientation changes are the causes. There is little or no conversion.

[0026] The following detailed description of an implementation of the method according to the invention will be given with reference to the accompanying drawings, in which: Other features and advantages of the invention will become apparent from the following examples, which are given for illustrative purposes only. The following descriptions are given for illustrative purposes only and are not intended to be limiting. [Brief description of the drawings]

[0027] [Figure 1] 1 shows an EFG type crystal growth method that makes it possible to obtain several sapphire single crystals from a plate-shaped single crystal sapphire seed prepared according to the present invention. [Diagram 2] 1 shows a blank for a watch crystal cut from a single crystal of sapphire obtained by growing the crystal in contact with a seed crystal of single crystal sapphire in the form of a plate prepared according to the present invention. [Diagram 3] 1 shows a bar-shaped single crystal sapphire seed prepared in accordance with the present invention. [Figure 4] Fig. 4A shows a so-called Kyropoulos ball grown along the crystal axis [A], from which a bar is taken, which serves as a seed crystal for the growth of a sapphire single crystal according to the invention. Fig. 4B shows a sapphire single crystal in the form of a Kyropoulos ball obtained using the seed crystal of Fig. 4A, from which a cylinder is taken, using a diamond tool, along the growth direction of the sapphire single crystal, so as to obtain a blank for a watch crystal according to the invention. Fig. 4C shows a so-called Kyropoulos ball, from which a cylinder is taken directly, using a diamond tool, so as to obtain a blank for a watch crystal according to the invention. [Diagram 5] FIG. 2 is a top view of a die for growing sapphire single crystals according to another embodiment of the method according to the invention. [Figure 6] FIG. 6 is a cross-sectional side view of the die of FIG. 5. [Figure 7] FIG. 2 is a top view of a watch crystal obtained by the method according to the invention, which is placed between two crossed polarizers. [Figure 8]Schematic diagram showing how a blank for a portable watch crystal is cut from an EFG type single crystal sapphire. [Figure 9] Schematic showing the cutting of a blank for a watch crystal from a single crystal sapphire cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In particular, the present invention provides a method for producing a sapphire crystal by contacting a seed crystal of single crystal sapphire in the form of a plate or bar. A blank cut from a single sapphire crystal grown in a molten state in a crucible. The invention is based on the creative concept of making a crystal for a portable watch. Specifically, the present invention relates to the following points: The fire seed crystal itself is the base unit of a single sapphire crystal from which the crystal blanks are cut. The surface is aligned so that the crystal axis [C] perpendicular to the crystal plane (0001) of the molecule is not included in the crystal plane. Specifically, the first sapphire single crystal is cut out, and the crystal is Either the axis [A], [C] or [M] is normal to the flat surface of the plate or the cross section of the bar. A plate-shaped single crystal surface with a flat surface that forms an angle within the range of 5 to 85 degrees. The crystal axes [A] and [C] of the single crystal sapphire seed crystal are determined. The misorientation of [M] or [M] occurs in the sapphire grown in contact with this single crystal sapphire seed crystal. The crystal of the watch is made of a single sapphire crystal. Finally, the crystal axis [C] extends in the plane of the windshield blank. Therefore, the crystal axis [C ] across the edge of a blank for a watch crystal. This avoids the most vulnerable part of the watch. This results in easier processing. In particular, the risk of chipping is significantly reduced. can be.

[0029] FIG. 1 shows a method for growing a sapphire single crystal using a seed crystal of a single crystal sapphire obtained according to the present invention. FIG. 1 shows a schematic diagram of an EFG type process for producing The single crystal sapphire seed crystal has two flat faces 4 extending parallel to and apart from each other. The seed crystal 1 of this single crystal sapphire is in the form of a plate 2 bounded by a , which are perpendicular to each other, are the crystal planes A(11-20) and C(0001 ) and M(10-10), which are perpendicular to the three crystal axes [A], [C], and [M]. It has a hexagonal crystal structure.

[0030] According to the present invention, for example, the crystal axis [C] of the obtained plate 2 is rotated around the crystal axis [M]. , the normal to the flat surface 4 of this plate 2 D1 and within the range of 5 to 85°, e.g. A single crystal sapphire is cut from the first single crystal sapphire so as to form an angle α of 10°. A seed crystal 1 of a fiber is formed. The crystal axes [A], [C] and [M] are perpendicular to each other. The crystal axis [A] is also offset by the same angle α with respect to the flat surface 4 of the plate 2, while the The axis [M] rotates 10° around itself and therefore does not move.

[0031] The technique for cutting out a seed crystal of a sapphire single crystal along a desired direction is As it is known to those skilled in the art of crystal growth, it will not be described in detail here.

[0032] As can be seen from FIG. 1, the seed crystal 1 of the single crystal sapphire is a sapphire single crystal 6. Long direction L The molten alumina and / or samarium oxide are pulled along the crystal axis [M] that defines the The fire is brought into contact with a single crystal sapphire seed crystal 1 at one of the tops of the die, The seed crystal 1 of single crystal sapphire is grown in the direction L The molten aluminum is gradually pulled up along the 3. The sapphire single crystal 6 is then slowly moved away from the sapphire and / or the nanowire. By making this possible, each sapphire single crystal 6 is obtained.

[0033] According to the present invention, a single crystal sapphire seed crystal 1 is used to grow a single crystal sapphire 6. A blank 8 for a crystal 10 for a portable watch is cut out from the sapphire single crystal 6. The blank 8 of such a watch crystal 10 is made up of two faces extending apart from each other. The boundary is formed by the two faces, at least one of which, face 12, is flat. The seed crystal 1 of crystalline sapphire is rotated around the crystal axis [M], for example. , normal to flat surface 4 of plate 2 D1 and the angle α is 5 to 85°, e.g., 10°. The plate 2 is cut from the initial sapphire single crystal so as to form a The misalignment of the crystal axes [A] and [C] in the seed crystal 1 of the single crystal sapphire The sapphire single crystal 6 is grown in contact with a crystalline sapphire seed crystal 1, and It is located in a blank 8 for a crystal 10 for a portable watch cut out of a single sapphire crystal 6 .

[0034] Finally, as shown in Figure 2, due to the misorientation of the crystal axes [A] and [C], [C] is not included within the flat surface 12 of the blank 8 of the crystal 10 for a watch, and therefore , do not cross the edges 14 of these blanks 8. Therefore, this crystal axis [C] The edge 14 of the blank 8 of the vertical watch crystal 10 is usually recognized as a cross section. Therefore, the most vulnerable part to the damage caused by the windshield 10 for the portable watch can be avoided. The blank 8 is less likely to break and is therefore easier to process. In particular, the risk of chipping is reduced. This reduces the load and reduces losses.

[0035] Figure 3 shows a single crystal sapphire bar 16A used in crystal growth methods such as the Kyropoulos type. The single crystal sapphire bars 16A are perpendicular to each other and The crystal planes A(11-20), C(0001) and M(10-10) of the basic unit cell of sapphire, respectively. It has a rhombohedral crystal structure that defines three perpendicular crystal axes [A], [C] and [M].

[0036] According to the present invention, as shown in FIG. 4A, a previously obtained sapphire single crystal ball 18A is Then, for example, rotate the sapphire around the crystal axis [M] to cut out a single crystal sapphire bar 16A. The crystal axis [A] of the obtained single crystal sapphire bar 16A is Cross section of 16A S Normal of D2 and forms an angle α in the range of 5 to 85°, for example 10°. The crystal axes [A], [C] and [M] are perpendicular to each other, and the crystal axis [C] is also a single Cross section of crystalline sapphire bar 16a S is offset by the same angle α with respect to the crystal axis [M] does not move because it rotates around itself (see Figure 4B). The misalignment of the crystal axes [A] and [C] in the bar 16A is the cause of the single crystal sapphire bar 16A, sapphire single crystal grown by contacting molten alumina and / or sapphire Next, the sapphire single crystal is cut using a diamond cutting tool 20. From the ball 18B, the sapphire single crystal ball 18B from the single crystal sapphire bar 16A growth direction D3 A single crystal sapphire cylinder 16B can be cut out along the line. Afterwards, the blanks 8 of the crystal 10 for the portable watch according to the present invention are successively cut into the single crystal sapphire. It can be cut out from cylinder 16B.

[0037] FIG. 4C shows a Kyropoulos type or other sapphire single crystal ball 18C. In this case, the crystal axis [A] of the growth of the sapphire single crystal ball 18C is 5 to 85 2. The cutting tool 20 is used to cut the cutter along a direction that forms an angle α in the range of 10°, for example 10°. This results in a blank for the crystal 10 for a portable watch according to the present invention. It is also possible to obtain a single crystal sapphire cylinder 16C from which 8 can be cut.

[0038] In addition, a Kyropoulos type or similar type was cut from a previously obtained sapphire single crystal ball along a desired direction. The technique for cutting a single crystal sapphire seed crystal is to make the seed crystal into a plate with a flat surface. Whether in the form of Bar 2 or Bar 16A, experts in the field of sapphire single crystal growth have As it is known to those skilled in the art, it will not be described in detail here.

[0039] Finally, the cross section of the single crystal sapphire bar 16A S Misalignment of the crystal axis [A] with respect to the normal Therefore, the crystal axis [C] is generally aligned with the flat surface 12 of the blank 8 of the crystal 10. and therefore generally do not straddle the edges 14 of these blanks 8. Therefore, this crystal axis [C] crosses the edge 14 of the blank 8 of the crystal 10. This avoids the greatest vulnerability usually found in portable devices. The blank 8 of the crystal 10 for the watch is less likely to break and, as a result, easier to process. The risk of occurrence is significantly reduced and losses are reduced.

[0040] Naturally, the invention is not limited to the embodiments described herein but is defined by the appended claims. Numerous simple modifications and variations are contemplated without departing from the scope of the invention as defined herein. In particular, as explained herein, the crystal axes form the boundaries of this plate. Single crystals in the form of plates that form a non-zero angle with the normal to the flat faces that form the Instead of preparing a seed crystal of sapphire, we first oriented the crystal along the crystal axis [C ] is, for example, conventionally applied to the flat surface 26 that forms the boundary of this first plate 24. A single crystal sapphire seed 22 in the form of a first plate 24 perpendicular to the In a particular embodiment of the present invention, such a single crystal substrate may be used. The fiber seeds 22 extend parallel to and apart from one another and are filled with molten alumina and / or At the top of the die 30, the sapphire is formed with a number of channels 32 running therethrough. The molten alumina and sapphire are then used to grow a single crystal 28. and / or sapphire comes into contact with the single crystal sapphire seed crystal 22 and begins to crystallize, The plate-shaped sapphire single crystal 28 is formed. These second single crystal sapphire plates are Each of the chambers is bounded by two flat surfaces 34 extending parallel to and apart from each other. In this case, a single crystal sapphire seed 22 is inserted into the channel 32 of the die 30. A direction perpendicular to the flat surface on which it extends P Within the range of 5 to 85 degrees, for example 10 2. The second single crystal substrate obtained by crystal growth is inclined by an angle α of 100°. In the case of the fire plate, the misorientation of the crystal axes is controlled as explained above with reference to FIG. The method of the flat surface 34 is compared with the plate obtained using a single crystal sapphire seed crystal having The misorientation of the crystal axis [A] relative to the line is the same.

[0041] FIG. 7 is a top view of a crystal 10 for a portable watch obtained by the method of the present invention; It is placed between two crossed polarizers. 10 was found to be free of defects such as dislocations or uncontrollable local orientation changes. In addition, according to the method of the present invention, it is possible to melt alumina and / or sapphire. It can be understood that these materials can be pure or doped. Preferably, the dopant is, alone or in combination, The metals are selected from the group consisting of tungsten, iron, chromium, cobalt and vanadium. The sapphire used is preferably a low quality sapphire crystal. Scrap or mechanically processed material from other steps in the manufacture of the watch crystal 10. In particular, in connection with the manufacture of the crystal 10 for a portable watch, The present invention has been described. Of course, such examples are given purely for illustrative purposes. The invention relates more generally to bridges, plates, cases, dials, wristwatches and the like of wristwatches. Manufacture of external and functional parts, especially for wristwatches and jewellery, such as the Tretlink This can be applied to the construction of

[0042] As shown in FIG. 8, a blank 8 for a watch crystal 10 is made of EFG type saffron. As shown in FIG. 9, a blank for a crystal 10 for a portable watch is cut from a single crystal 6 of the same material. The single crystal sapphire cylinder 16B is machined and cut out. The cylinder 16B is a sapphire single crystal ball 18 made from the single crystal sapphire bar 16A. B growth direction D3 18B from the sapphire single crystal ball 18B along the line. Specifically, the blank 8 of the crystal 10 for a portable watch is made of a sapphire single crystal ball 18B. Long direction D3 Typically, the blank 8 of the crystal 10 for a portable watch is cut perpendicular to the The thickness is in the range of 1-2 mm and can reach 10 mm. In this case, the term "bar" refers to the seed crystal, and the term "cylinder" refers to the sapphire single crystal. It is used as applied to crystals. [Explanation of symbols]

[0043] 1. Single crystal sapphire seed 2 Plate 4 Flat surface α angle D1 Normal L growth direction 6. Sapphire single crystal 8 Blank 10. Windshields for portable watches 12 Flat Surface 14 Edge 16A Single Crystal Sapphire Bar 16B Single crystal sapphire cylinder 16C single crystal sapphire cylinder 18A Sapphire single crystal ball 18B Sapphire single crystal ball 18C Sapphire Single Crystal Ball D2 Normal S cross section D3 growth direction 20 cutting tools 22 Single crystal sapphire seed crystal 24 First Plate 26 Flat Surface 28 Sapphire single crystal 30 Die 32 Channels 34 Flat Surface

Claims

[Claim 1] 1. A method for producing a single crystal sapphire seed crystal, comprising: The single crystal sapphire seed crystal (1) has three crystal axes [A], [C] and [M]. It has a rhombohedral crystal structure, The three crystal axes [A], [C] and [M] are perpendicular to each other and are bonded to each other. perpendicular to the crystal planes A(11-20), C(0001) and M(10-10); The single crystal sapphire seed crystal (1) is made up of two flat plates extending parallel to and apart from each other. a plate (2) bounded by a flat surface (4), The single crystal sapphire plate (2) has a crystallinity of the single crystal sapphire plate (2). Any of the axes [A], [C] or [M] of the single crystal sapphire plate (2) The initial surface is adjusted to form an angle (α) of 5 to 85° with the normal (D1) of the flat surface (4). It is obtained by cutting a single crystal of Oia. A method characterized by:

Images