Patent Publication Number: US-2013237402-A1

Title: Sapphire material and production method thereof

Description:
The application claims the benefit of Taiwan Patent Application No. 101107556, filed on Mar. 6, 2012, in the Taiwan Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a sapphire substance and the manufacturing method thereof, particularly to a sapphire substance obtained from a sapphire crystal growing along its a-axis and the manufacturing method thereof. 
     BACKGROUND OF THE INVENTION 
     Recently, the demand for the components used in smart phones is increased due to the increased circulation of the smart phones. These components include protecting lens used for the cameras and the cover glasses used for the touch panels of the mobile phones, and most of them have a major material of glass. Although the glass materials have the advantages such as the fine appearance, simple processing procedures, low cost, and so on, the defects of unfavorable mechanical properties including the hardness and the compressive strength cause problems in the practical applications. The techniques such as hard coating and chemical toughening/tempering could be used to improve the above defects, but result in other problems such as the additional processing cost and environmental problems. 
     Corundum is a crystalline form of the aluminium oxide (Al 2 O 3 ). Pure corundum is in fact clear, and blue Corundum, or sapphire, is made up of corundum (Al 2 O 3 ), and iron and titanium impurities (Fe 2+  and Ti 4+ ), which are responsible for the blue coloration. Red corundum, or ruby, is made up of corundum (Al 2 O 3 ), and chromium impurities (Cr 3+ ), which are responsible for the red coloration. Sapphire is a crystal with trigonal symmetry; its 3-fold axis, also referred to as the optical axis, is usually designated as c-axis. The a- and m-axis are both perpendicular to the c-axis. The rhombohedral cleavage plane, designated as R, is inclined at 57.6° from the c-axis in the direction of the m-axis. The sapphire single crystals are widely used as an industrial material because of its excellent mechanical characteristics, chemical stability, and optical properties, and in particular, are used for a GaN film-forming substrate for manufacturing a blue/white light emitting diode (LED). 
     Table 1 shows the comparisons of physical properties and optical characteristics among sapphires with various orientations and the tempered glass. In this Table, “Sapphire C-axis”, “Sapphire A-axis”, “Sapphire R-axis” and “Sapphire M-axis” indicate sapphire substances obtained from a sapphire crystal in a c-axis direction, an a-axis direction, an r-axis direction and an m-axis direction, respectively. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Sapphire 
                 Sapphire 
                 Sapphire 
                 Sapphire 
                 Tempered 
               
               
                   
                 Unit 
                 C-axis 
                 A-axis 
                 R-axis 
                 M-axis 
                 glass 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Vickers 
                 Kgf/cm 2   
                 2150 ± 50  
                 1850 ± 50  
                 2200 ± 50  
                 1850 ± 50  
                 674 
               
               
                 Hardness 
               
               
                 Young Modulus 
                 GPa 
                 460 ± 50 
                 460 ± 50 
                 460 ± 50 
                 460 ± 50 
                 71.7 
               
               
                 Compressive 
                 MPa 
                 ≧2000 
                 ≧2000 
                 ≧2000 
                 ≧2000 
                 ≧800 
               
               
                 strength 
               
               
                 Thermal 
                 W/m-k 
                 32 ± 5 
                 32 ± 5 
                 32 ± 5 
                 32 ± 5 
                 1.2 
               
               
                 conductivity 
               
               
                 Transmittance 
                 % 
                   &gt;85 
                   &gt;85 
                   &gt;85 
                   &gt;85 
                 &gt;90 
               
               
                   
               
            
           
         
       
     
     In Table 1, the sapphires with various orientations show better hardness and compressive strength than the tempered glass. Further, the sapphires being treated with proper processes and membrane coatings would have the optical characteristic similar to that of the tempered glass. Therefore, the combination of favorable chemical, electrical, mechanical, optical, thermal and durability properties makes sapphire a preferred material for high performance system and component designs. 
     Several techniques for the production of sapphire are known including the Verneuile technique, Kyropoulos, heat exchange method and so on. The sapphire made by the Verneuile technique is fragile and small, and thus is not suitable to apply to large-size applications. In addition, the edge defined film-fed growth (EFG) techniques have been used to grow the single crystal sapphire in several planar configurations including a-plane and c-plane. 
     In the US patent with the Publication No. 20080075941, a method and apparatus for the production of c-plane single crystal sapphire useful in the substrate of LEDs, such as gallium nitride LEDs, is disclosed. In that patent, for forming single crystal c-plane sapphire material, the method for growing the single crystal sapphire exhibiting a c-axis orientation is disclosed. However, the single crystal sapphire growing via that method not only has the defects of long growth time and energy consuming, but also is unfavorable to the subsequent processes. 
     Hence, because of the defects in the prior arts, the inventors provide a sapphire substance and the manufacturing method thereof to effectively overcome the demerits existing in the prior arts. 
     SUMMARY OF THE INVENTION 
     Compared with the method for manufacturing the sapphire growing along its c-axis, it is verified that the method for manufacturing the sapphire growing along its a-axis provided in the present application is more efficient in the production, and the manufactured sapphire with a growth axis of the a-axis has a lower dislocation density. Based on different requirements, the sapphire growing along its a-axis provided in the present application could be widely used in various applications. 
     In accordance with one aspect of the present invention, a pharmaceutical composition for preventing or treating a chronic heart disease, particularly a chronic heart failure, is provided. 
     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1(   a ) is a diagram showing a Kyropoulos crystal growing device according to a first preferred embodiment of the present application. 
         FIG. 1(   b ) is a diagram showing the sapphire crystal formed in the present application. 
         FIG. 2  is a diagram showing the method for manufacturing the sapphire substance according to the first preferred embodiment. 
         FIG. 3  is a diagram showing a heat exchange device according to a second preferred embodiment of the present application. 
         FIG. 4  is a diagram showing the method for manufacturing the sapphire substance according to the second preferred embodiment. 
         FIG. 5(   a ) is a diagram showing a wire cutting machining device according to a third preferred embodiment of the present application. 
         FIG. 5(   b ) is another diagram showing the wire cutting machining device according to the third preferred embodiment of the present application. 
         FIG. 6(   a ) is a diagram showing a grinding device according to a fourth preferred embodiment of the present application. 
         FIG. 6(   b ) is a diagram showing another grinding device according to the fourth preferred embodiment of the present application. 
         FIG. 7  is a diagram showing a polish device according to a fifth preferred embodiment of the present application. 
         FIG. 8  is a diagram showing manners for shaping the polished sapphire substrate according to a sixth preferred embodiment of the present application. 
         FIG. 9  is a diagram showing a process of shaping the polished sapphire substrate according to a seventh preferred embodiment of the present application. 
         FIG. 10  is a diagram showing the procedure of manufacturing and processing the sapphire substrate of the present application. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for the purposes of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed. 
     The sapphire substance (or the sapphire material or the sapphire crystal), the manufacturing method thereof and the processing manners thereof are described in the following embodiments. The abovementioned manufacturing method and processing manners could be applied to other corundum materials, such as the ruby. The applications of the sapphire substance have been disclosed in Taiwan Patent Application No. 100142110 and Taiwan Patent Application No. 100149015, which are incorporated herein by reference. 
     It is noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. 
     Please refer to  FIG. 1(   a ), which is a diagram showing a Kyropoulos crystal growing device  20  according to a first preferred embodiment of the present application. The Kyropoulos crystal growing device  20  includes a resistance heater  201 , a container such as a crucible  202 , copper coils  206  with current running through and heat shields  207 . The resistance heater  201  is made of a material including tungsten or tungsten alloys and is coupled to the copper coils  206 . When an electrical current is applied to the copper coils  206 , the resistance heater  201  generates heat and provides the generated heat to the crucible  202 . The sapphire material, which is the high-purity Al 2 O 3 , is melted down to a liquid state in the crucible  202  via the resistive heating, and forms a melt  203 , i.e. the molten Al 2 O 3 . The crucible  202  may be made of any material capable of containing the melt  203 . Suitable materials for the construction of the crucible  202  include, for example, at least one of iridium, molybdenum, tungsten, molybdenum/tungsten alloys and graphite. A sapphire seed  205  is placed in a proper position in the Kyropoulos crystal growing device  20  for generating a sapphire crystal growing along its a-axis. The Kyropoulos crystal growing device  20  causes the formation of a solid-liquid interface substance  204  between the sapphire seed  205  and the melt  203 . The heat shields  207  are made of a material including at least one of molybdenum and tungsten, which can help to reduce the heat loss from the crucible  202  for maintaining the temperature inside of the crucible  202 . 
     According to the first preferred embodiment of the present invention, the method for manufacturing the sapphire substance is described as follows. Firstly, the sapphire material, which is the high-purity Al 2 O 3 , is placed in the crucible  202 , and the sapphire seed  205  is positioned to contact with the sapphire material for generating a crystal growing in a direction of its a-axis. In  FIG. 1(   a ), the a-axis of the sapphire seed  205  is parallel to the pulling direction, i.e. the vertical direction. The sapphire material is then melted down in the crucible  202  via the resistive heating to form the melt  203 , i.e. the molten Al 2 O 3 , or form the melt  203  and the solid-liquid interface substance  204 . The melt  203  is gradually cooled by a temperature gradient caused by gradually pulling the sapphire seed  205  upwardly, and the crystallization of the melt  203  and the solid-liquid interface substance  204  onto the sapphire seed  205  is initiated about the a-axis of the sapphire seed  205 . Finally, after the completion of the above crystallization, the sapphire crystal  208  is formed and removed from the crucible  202 . 
     Please refer to  FIG. 1(   b ), which is a diagram showing the sapphire crystal  208  formed in the present application. As shown, the sapphire crystal  208  has a growth axis parallel to the a-axis. Next, the sapphire substance  209  is obtained from the sapphire crystal  208  so as to perform the subsequent procedures, and preferably, the orientations of the sapphire crystal  208  are determined by the x-ray diffraction based on the demand prior to obtaining the sapphire substance  209 . The method for obtaining the sapphire substance  209  includes the manner of drilling or cutting the sapphire crystal  208 . For example, a hollow cylindrical drill coated with diamond grain around the cutting edge of drill could be used to obtain the cylindrical sapphire substance  209 , and a diamond saw could be used to cut the sapphire crystal  208  for obtaining the sapphire substance  209  with a shape of a rectangular column or a polygonal column. The sapphire substance  209  is obtained in a particular direction substantially perpendicular to the a-axis. The sapphire substance  209  may be obtained from the sapphire crystal  208  in the horizontal direction, i.e. the c-axis in the example of  FIG. 1(   b ) or the m-axis (not shown), perpendicular to the a-axis, wherein the c-axis is perpendicular to the m-axis. 
     In another preferred embodiment, the particular direction could be a direction tilted from the c-axis of the sapphire crystal  208  by an angle in a range of −2.5° to 2.5° toward the a- and m-axis. The sapphire substance  209  obtained in the direction defined above has a better transmittancy. When it is intended to obtain the sapphire substance  209  in a direction parallel to the c-axis completely perpendicular to the a-axis, it is not easy to drill the sapphire crystal  208  because of its structure. Accordingly, the abovementioned particular direction is preferably a direction inclined from the c-axis of the sapphire crystal  208  to the a-axis by −2.5° to 2.5°; a direction inclined from the c-axis of the sapphire crystal  208  to the m-axis by −2.5° to 2.5°; a direction inclined from the a-axis of the sapphire crystal  208  to the c-axis by an angle in a range of −2.5° to 2.5°; a direction inclined from the a-axis of the sapphire crystal  208  to the m-axis by an angle in a range of −2.5° to 2.5°; a direction inclined from the m-axis of the sapphire crystal  208  to the c-axis by an angle in a range of −2.5° to 2.5°; a direction inclined from the m-axis of the sapphire crystal  208  to the a-axis by an angle in a range of −2.5° to 2.5°; or a direction parallel to the r-axis of the sapphire crystal  208 . Based on the above preferred particular directions, it is easy to perform the drilling procedure and the obtained sapphire substance  209  would have a better transmittancy. The Miller indices of the above particular directions include: the c-axis (0001), the a-axis (  1   1  20;1  2  10;2  1   1  0;11  2  0;  1  2  1  0;  2  110), the m-axis (0  1  10;1  1  00;10  1  0;01  1  0;  1  100;  1  010) and the r-axis (10  1 1;1  1 0  1 ;01  1   1 ;  1 01  1 ;  1 101;0  1 11). 
     Please refer to  FIG. 2 , which is a diagram showing the method for manufacturing the sapphire substance  209  according to the first preferred embodiment. The method includes the following steps. In Step S 201 , a sapphire seed  205  is contacted with a melt  203 . In Step S 202 , the sapphire seed  205  is pulled upwardly to cool the melt  203  gradually and cause the crystallization of the melt  203  along the a-axis of the sapphire seed  205  to form a sapphire crystal  208 . In Step S 203 , the sapphire substance  209  is obtained from the sapphire crystal  208  in a particular direction, preferably perpendicular to the a-axis of the sapphire seed  205  or the sapphire crystal  208 . 
     Please refer to  FIG. 3 , which is a diagram showing a heat exchange device  30  according to a second preferred embodiment of the present application. The heat exchange device  30  includes a resistance heater  301 , a crucible  302 , a sapphire seed  305 , at least one current coil  306  coupled to the resistance heater  301 , heat shields  307  and heat exchange pipes  308 . When the current coil  306  is applied with an electrical current, the crucible  302  would be heated by an energy provided by the resistance heater  301 . The melt  303  may be formed from the sapphire material, i.e. the high-purity Al 2 O 3 . A sapphire seed  305  is placed in a proper position in the heat exchange device  30  for generating a sapphire crystal growing in a direction parallel to its a-axis. The heat exchange device  30  causes the formation of a solid-liquid interface substance  304  between the sapphire seed  305  and the melt  303 . 
     Based on the second preferred embodiment of the present invention, the method for manufacturing the sapphire substance is described as follows. Firstly, the sapphire material, which is the high-purity Al 2 O 3 , is placed in the crucible  302 , and a seeding procedure is performed by contacting the sapphire seed  305  with the sapphire material. In  FIG. 3 , the a-axis of the sapphire seed  305  is parallel to the vertical direction. The sapphire material is then melted down in the crucible  302  via the resistive heating to form the melt  303 , i.e. the molten Al 2 O 3 , or form the melt  303  and the solid-liquid interface substance  304 . The heat in the solid-liquid interface substance  304  and the melt  303  is removed by a heat exchange manner by the cooling water or the vapor circulating in the heat exchange pipes  308  so that the solid-liquid interface substance  304  and the melt  303  is cooled gradually from the bottom to the top, and the crystallization of the melt  303  and the solid-liquid interface substance  304  onto the sapphire seed  305  is initiated about the a-axis of the sapphire seed  305 . Finally, a sapphire crystal  208  having a growth axis parallel to its a-axis the same as that shown in  FIG. 1(   b ) is formed after the termination of the above crystallization. The crucible  302  may be any shape or size that is suitable for forming the crystals with a desired shape, so as to increase the volume utilization of the crystals during the subsequent procedures. For example, the crucible  302  may be substantially rectangular, square, cylindrical or polygonal. The shape of the sapphire crystal  208  would be varied depending on the shape of the crucible  302 . Next, the procedures for obtaining the sapphire substance  209  from the sapphire crystal  208  are the same as those described above and thus are not described repeatedly herein. 
     Please refer to  FIG. 4 , which is a diagram showing the method for manufacturing the sapphire substance  209  according to the second preferred embodiment. The method includes the following steps. In Step S 301 , a sapphire seed  305  is contacted with a melt  303 . In Step S 302 , the melt  303  is cooled gradually via the heat exchange manner and cause the crystallization of the melt  303  along the a-axis of the sapphire seed  305  to form a sapphire crystal  208 . In Step S 303 , the sapphire substance  209  is obtained from the sapphire crystal  208  in a particular direction, preferably perpendicular to the a-axis of the sapphire seed  305  or the sapphire crystal  208 . 
     The crystal axis of the sapphire substance  209  is preferably one of the c-axis (0001), the a-axis [including (1  2 10), (11  2 0), (2  1   1 0), (  1   1 20), (  2 110), and (  1 2  1 0)], the m-axis [including (  1 010), (  1 100), (01  1 0), (10  1 0), (1  1 00), and (0  1 10)] and the r-axis [including (10  1 1), (  1 01  1 ), (01  1   1 ), (0  1 11), (1  1 0  1 ), and (  1 101)]. After the sapphire substance  209  is obtained from the sapphire crystal  208 , it is processed by a series of operations, such as dicing, drilling, milling, grinding, edge grinding, polishing, beveling, cutting, coating, and so on. 
     Please refer to  FIGS. 5(   a ) and  5 ( b ), each of which is a diagram showing a wire cutting machining device  40  according to a third preferred embodiment of the present application. The wire saw cutting machining device  40  includes a driving device  42 . The driving device  42  includes a primary sheave roller  44  and a set of guide-rollers  46 . A plurality of diamond wires  48  are wound around the driving device  40 , and may be separated by a distance ranged between 0.65 to 1.85 mm, and thus the cutting spacing for the sapphire substance  209  may be ranged between 0.65 to 1.85 mm. When the sapphire substance  209  is to be sliced off, a force, F, is applied to the sapphire substance  209 , and the driving device  42  performs a rocking motion so that the plurality of diamond wires generate a wire tension, T. Due to the wire tension, T, and the movement of the diamond wires, the sapphire substance  209  is sliced into at least one sapphire substrate  504  with a thicknesses ranged between 0.4 to 1.6 mm. 
     Please refer to  FIG. 6(   a ), which a diagram showing a grinding device  50  according to a fourth preferred embodiment of the present application. The grinding device  50  includes an upper grinding disk  501 , a lower grinding disk  505  and a hollow carrier disk  503 . Since after the wire cutting, there might be saw marks on a first surface  5041  and a second surface  5042  of the sapphire substrate  504 , the processes of grinding and thinning may be required. Firstly, the sapphire substrate  504  is placed in the hollow carrier disk  503  and fixed between the upper grinding disk  501  and the lower grinding disk  505 , and the grind would be achieved via the rotations of the upper grinding disk  501  and the lower grinding disk  505 . The hollow carrier disk  503  has gears  5031  configured inside and outside of the rim thereof and engaging with the inside gear  5011  of the upper grinding disk  501  and the outside gear of the lower grinding disk  505 . Through the engagement of the gears, the hollow carrier disk  503  and the sapphire substrate  504  fixed therein are moved by the rotations of the upper grinding disk  501  and the lower grinding disk  505 . While the hollow carrier disk  503  is moved, a grinding slurry  502  is fed into the upper grinding disk  501 , and the first surface  5041  and the second surface  5042  of the sapphire substrate  504  are ground by the upper grinding disk  501  and the lower grinding disk  505 , respectively. Preferably, the grinding slurry  502  comprises diamond grains. 
     Please refer to  FIG. 6(   b ), which a diagram showing another grinding device  60  according to the fourth preferred embodiment of the present application. In another preferred embodiment, the grinding device  60  comprises a carrier disk  603  and an upper grinding disk  607 . The grinding media such as the diamond grains  606  could be fixed on the upper grinding disk  607  by the electroforming, the resin adhesive or the like. While the sapphire substrate  504  fixed on the carrier disk  603  with wax or glue is ground, a grinding slurry  608  is used to cool and lubricate the sapphire substrate  504 , the upper grinding disk  607  and the diamond grains  606 . 
     Please refer to  FIG. 7 , which is a diagram showing a polish device  70  according to a fifth preferred embodiment of the present application. After the grinding process, there may be still tiny scars on the surface of the ground sapphire substrate  702 , and thus a polishing process is required. The polish device  70  comprises an upper polishing disk  701 , a lower polishing disk  704  and a polishing carrier disk  703 . Firstly, the sapphire substrate  702  that has been ground is placed on the polishing carrier disk  703 , which could be a ceramic disk or a glassfiber disk. Then, the polishing carrier disk  703  is adhered or fixed to the upper polishing disk  701 , and the polishing slurry (fluid)  706  is provided between the sapphire substrate  702  and the lower polishing disk  704 . The upper polishing disk  701  is slowly pressed down and meanwhile the upper polishing disk  701  and the lower polishing disk  704  are rotated. 
     After one surface of the sapphire substrate  702  is polished, the sapphire substrate  702  is reversed to repeat the above-mentioned polishing steps for another surface thereof. The first surface  7021  and the second surface  7022  are polished by the polishing fluid  706  and form a third surface  8051  and a fourth surface  8052  (shown in  FIG. 8 ), respectively. As shown in  FIG. 8 , each of the third surface  8051  and the fourth surface  8052  has a flatness and a roughness, and the polished sapphire substrate  702  has a total thickness variation (TTV) and a bow value. After the polishing process, the flatness could be controlled in a range of 0-20 micron/inch, the roughness could be controlled in a range of 0.2-10 nm, the TTV could be controlled in a range of 0-15 micron/inch, and the bow value could be controlled in a range of −30 to +30 micron. 
     Please refer to  FIG. 8 , which is a diagram showing processes for shaping the polished sapphire substrate  805  according to a sixth preferred embodiment of the present application. The sapphire substrate  805  processed by the grinding and polishing procedures could be cut into a particular shape with a mechanical process or a chemical process. The mechanical process could be achieved by cutting wheels  806 , a high speed CNC machine  804 , a laser system  802  or a diamond saw  801 . The chemical process could be achieved by etching the sapphire substrate  805  via a chemical agent. 
     Please refer to  FIG. 9 , which is a diagram showing a process of shaping the polished sapphire substrate  805  according to a seventh preferred embodiment of the present application. If the shaped sapphire substrate has serrate ends, the serrate surface thereof such as the fifth surface  903  could be smoothed with an apparatus such as a diamond grinder  901 . In a preferred embodiment, the diamond grinder  901  could be a T-type grinder. In another preferred embodiment, the diamond grinder  901  could be replaced with an R-type grinder, a C-Type grinder or a flat-head grinder depending on the demand for the products. In the seventh embodiment, the movement of the diamond grinder  901  is programmed by the computer numerical tracer control. Further, the fifth surface  903  of the sapphire substrate  805  could be shaped into any desired shapes via the tracer control. For example, the fifth surface  903  could be ground to have a circular, square, polygonal or irregular shape, or have a chamfer or round angle within a desired angle range. Subsequently, a coating or decorating process may be applied to the sapphire substrate  805 . 
     Please refer to  FIG. 10 , which is a diagram showing the procedure of manufacturing and processing the sapphire of the present application. The method comprises the following steps. In Step S 401 , the sapphire crystal  208  is growing from the cooled solid-liquid interface substances  204 ,  304  and the melts  203 ,  303 , and selectively, the crystal orientation of the sapphire crystal  208  could be measured with a measuring device. In Step S 402 , the sapphire substance  209 , which may be a cylindrical crystal rod, a rectangular brick or a polygonal brick, is obtained from the sapphire crystal  208 . In Step S 403 , a multi-wire diamond cutting process is performed to the sapphire substance  209  so as to form the sapphire substrate  504 . In Step S 404 , the grinding and polishing processes are performed, and then the sapphire substrate  805  is washed and checked for any holes or defects on the third surface  8051  and the fourth surface  8052  where the holes or defects may cause a decrease in the hardness or the compressive strength. After the above check, a process of stress releasing may be performed to the sapphire substrate  805 , and then Steps S 405  and S 406  could be performed. In Step S 405 , a shape cutting process is performed. In Step S 406 , a shape grinding process is performed. In Steps S 405  and Step S 406 , a mechanical process or a chemical process could be selected depending on the required size and shape of the final product. In Step S 407 , a coating or decorating process is performed on the sapphire substrate  805 . Finally, an annealing treatment to the surface of the sapphire substrate  805  is selectively performed based on the surface condition. The optical properties such as the transmittance may be determined so as to confirm that the sapphire substrate  805  with the optical properties complying with the requirements could be applied to various devices. 
     Both the first preferred embodiment and the second preferred embodiment of the present application include Steps S 401  and S 402 , the difference there between is that different devices and methods are used to manufacture the sapphire substance  209 . Step S 403  shown in  FIG. 10  is also included in the third preferred embodiment of the present application. Step S 404  shown in  FIG. 10  is also included in the fourth and fifth preferred embodiments of the present application. Step S 405  and Step S 406  shown in  FIG. 10  are included in the sixth and seventh preferred embodiments, respectively. It is noted that Steps S 401 -S 407  could be performed in order. However, the double-headed arrows among Steps S 404 , S 405  and S 406  indicate these steps could be performed in any order due to the good physical properties, e.g. the high hardness, of the sapphire. Further, one skilled in the art could selectively perform at least one of Steps S 404 , S 405  and S 406  according to the actual demands. For example, after the multi-wire diamond cutting process in Step S 403 , the sapphire substance could merely be processed by the shape grinding in Step  406  prior to entering Step S 407 . 
     After the completion of Steps S 404 , S 405  and/or Step S 406 , the sapphire substrate would have a transparent appearance and could be a sapphire glass with a transmittance equal to or greater than 85%, and a subsequent process such as the process of coating a reflective layer for improving the optical characteristics thereof could be performed. 
     In Step S 407 , the further processes for the sapphire substrate may include the functional coating and/or decorative coating. The functional coating is including but not limited to the process of coating an anti-reflective layer on the sapphire substrate for increasing the transmittance to 90% or more. The decorative coating is including but not limited to the processes of coating a metal-containing layer on the sapphire substrate for increasing the metallic luster and various printing processes, e.g. the ink transfer printing. 
     The sapphire glass could be applied to the touch panel or the protecting lens of a camera module. Due to the outstanding properties such as the high hardness and compressive strength, the sapphire glass could replace the tempered glass and applied to various devices. 
     While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the functions and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the present invention. 
     Embodiments 
     1. A method for manufacturing a sapphire substance, comprising steps of:
         providing a sapphire crystal having an a-axis and a growth axis parallel to the a-axis; and   obtaining the sapphire substance from the sapphire crystal in a particular direction, wherein the sapphire crystal has a c-axis, an m-axis and an r-axis, and the particular direction includes one selected from a group consisting of:
           a first direction deflected from the c-axis of the sapphire crystal toward the a-axis by an angle having a range of −2.5° to 2.5°   and toward the m-axis by the angle having a range of −2.5° to 2.5°;   a second direction deflected from the a-axis of the sapphire crystal toward the c-axis by the angle having a range of −2.5° to 2.5°   and toward the m-axis by the angle having a range of −2.5° to 2.5°;   a third direction deflected from the m-axis of the sapphire crystal toward the c-axis by the angle having a range of −2.5° to 2.5°   and toward the a-axis by the angle; and   a fourth direction is the r-axis of the sapphire crystal.   
               

     2. A method for manufacturing a corundum substance, comprising steps of:
         providing a corundum crystal seed having an a-axis;   growing a corundum crystal boule along the a-axis from the corudum seed; and   obtaining the corundum substance from the corundum crystal in a particular direction.       

     3. The method of the embodiment 2, wherein the corundum crystal is a sapphire crystal having the a-axis, and the corundum substance is a sapphire substance, and the step of providing the sapphire crystal includes sub-steps of:
         melting a sapphire material into a melt;   contacting a sapphire seed with the melt; and   initiating a crystallization of the melt onto the sapphire seed to form the sapphire crystal growing along the a-axis.       

     4. The method of any of the preceding embodiments, wherein the sapphire material is melted in a crucible. 
     5. The method of any of the preceding embodiments, wherein the crucible has a shape being one selected from a group consisting of a cylindrical shape, a rectangular shape and a polygonal shape. 
     6. The method of any of the preceding embodiments, wherein the step of initiating the crystallization of the melt includes a sub-step of:
         pulling the sapphire seed upwardly for generating a temperature gradient.       

     7. The method of any of the preceding embodiments, wherein the melt includes a molten Al 2 O 3 . 
     8. The method of any of the preceding embodiments, wherein the sapphire crystal has a c-axis, an m-axis and an r-axis, and the particular direction includes one selected from a group consisting of:
         a first direction deflected from the c-axis of the sapphire crystal toward the a-axis by an angle having a range of −2.5° to 2.5°   and toward the m-axis by the angle having a range of −2.5° to 2.5°;   a second direction deflected from the a-axis of the sapphire crystal toward the c-axis by the angle having a range of −2.5° to 2.5°   and toward the m-axis by the angle having a range of −2.5° to 2.5°;   a third direction deflected from the m-axis of the sapphire crystal toward the c-axis by the angle having a range of −2.5° to 2.5°   and toward the a-axis by the angle having a range of −2.5° to 2.5°; and   a fourth direction parallel to the r-axis of the sapphire crystal.       

     9. The method of any of the preceding embodiments, wherein the particular direction has a Miller index being one selected from a group consisting of a c-axis (0001); an a-axis (  1   1  20;1  2  10;2  1   1  0;11  2  0;  1  2  1  0;  2  110), the m-axis (0  1  10;1  1  00;10  1  0;01  1  0;  1  100;  1  010) and the r-axis (10  1 1;1  1 0  1 ;01  1   1 ;  1 01  1 ;  1 101;0  1 11). 
     10. The method of any of the preceding embodiments, wherein the corundum substance is obtained by at least one of a drilling manner and a cutting manner. 
     11. The method of any of the preceding embodiments, further comprising a step of:
         slicing the sapphire substance into a sapphire substrate having a thicknesses ranged between 0.4 and 1.6 mm.       

     12. The method of any of the preceding embodiments, further comprising a step of:
         slicing the sapphire substance into a plurality of sapphire substrates by a plurality of diamond wires separated by a distance ranged between 0.65 and 1.85 mm.       

     13. The method of any of the preceding embodiments, wherein the sapphire substrate has a first surface and a second surface, and the method further comprises at least a process being one selected from a group consisting of:
         grinding at least one of the first surface and the second surface with a grinding media;   polishing at least one of the first surface and the second surface with a polishing slurry;   cutting the sapphire substrate by at least one of a mechanical process and a chemical process;   coating a membrane on the sapphire substrate; and   performing an ink transfer printing on the sapphire substrate.       

     14. The method of any of the preceding embodiments, wherein each of the first surface and the second surface of the processed sapphire substrate has a flatness in a range of 0-20 micron/inch and a roughness in a range of 0.2-10 nm. 
     15. The method of any of the preceding embodiments, wherein the membrane includes one of an anti-reflective membrane and a metal-containing membrane. 
     16. The method of any of the preceding embodiments, wherein the processed sapphire substrate has a total thickness variation (TTV) ranged between 0 and 15 micron/inch and a bow value ranged between −30 and +30 micron. 
     17. The method of any of the preceding embodiments, wherein the sapphire substrate is processed to form a sapphire glass having one of transmittances equal to and greater than 85%. 
     18. The method of any of the preceding embodiments, wherein the sapphire substrate has a serrate end, and the method further comprises a step of processing the sapphire substrate by grinding the serrate end to form one of a chamfer and a round angle. 
     19. A corundum substance obtained from a corundum crystal in a particular direction, wherein the corundum crystal has an a-axis, a c-axis, an m-axis, an r-axis and a growth axis parallel to the a-axis, and the particular direction includes one selected from a group consisting of:
         a first direction deflected from the c-axis of the corundum crystal toward the a-axis by an angle having a range of −2.5° to 2.5°   and toward the m-axis by the angle having a range of −2.5° to 2.5°;   a second direction deflected from the a-axis of the corundum crystal toward the c-axis by the angle having a range of −2.5° to 2.5°   and toward the m-axis by the angle;   a third direction deflected from the m-axis of the corundum crystal toward the c-axis by the angle having a range of −2.5° to 2.5°   and toward the a-axis by the angle; and or   a fourth direction parallel to the r-axis of the corundum crystal.       

     20. The corundum substance of the embodiment 19, wherein the corundum crystal is one of a sapphire crystal and a ruby crystal. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclose embodiments. Therefore, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.