A large-size yag crystal growth system based on a resistance furnace

Abstract

This utility model discloses a large-size YAG crystal growth system based on a resistance furnace, relating to the field of laser crystal growth technology. The large-size YAG crystal growth system is an axially independent three-section temperature control system, including an upper temperature control system, a middle temperature control system, and a lower temperature control system. The upper temperature control system includes a reaction device and a heat preservation device, which includes side heat preservation components and a top heat preservation component. The middle temperature control system includes a support device and a first heat transfer device. The lower temperature control system includes a second heat transfer device and a bottom heat preservation component. This system achieves precise control of the multi-layer gradient temperature field, reduces crystal cracking caused by excessive stress during crystal growth, ensures high purity and uniformity of the crystal, and successfully achieves stable mass production of YAG crystals with diameters greater than φ50mm. It significantly improves the growth quality and production efficiency of large-size YAG crystals, possesses high practical value, and provides solid technical support for the manufacture of high-precision optical devices.

Description

Technical Field

[0001] This utility model relates to the field of laser crystal growth technology, and more specifically, to a large-size YAG crystal growth system based on a resistance furnace. Background Technology

[0002] YAG (yttrium aluminum garnet) crystals, as high-performance laser materials, are widely used in industrial processing and medical equipment due to their excellent optical properties and thermal stability. Traditional YAG crystal growth technology requires the rare metal iridium as a crucible, which is costly, has a long growth cycle, and involves iridium loss during crystal growth. The maintenance of the iridium crucible and iridium rod also faces high costs, severely hindering its industrialization. Existing technologies use resistance furnaces to grow laser crystals instead of traditional induction furnaces. However, existing resistance furnace growth technologies often suffer from the following problems: large-sized crystals (diameter > 50mm) are prone to stress concentration due to uneven thermal field; there are more volatiles during growth, leading to defects such as crystal cracking and component segregation; and the automation level is low, making it difficult to meet the needs of large-scale production.

[0003] In view of this, this utility model is proposed. Utility Model Content

[0004] The purpose of this invention is to provide a large-size YAG crystal growth system based on a resistance furnace to solve the above-mentioned technical problems.

[0005] This utility model is implemented as follows: In the first aspect, this utility model provides a large-size YAG crystal growth system based on a resistance furnace. The large-size YAG crystal growth system is an axially independent three-section temperature control system, including an upper temperature control system, a middle temperature control system and a lower temperature control system. The three independent axial temperature control systems are both independent and interconnected, which is conducive to achieving precise control of the multi-layer gradient temperature field and reducing crystal cracking caused by excessive stress during crystal growth. The upper temperature control system includes a reaction device and a heat preservation device, which includes side heat preservation components and a top heat preservation component; the middle temperature control system includes a support device and a first heat transfer device; the lower temperature control system includes a second heat transfer device and a bottom heat preservation component; the first heat transfer device connects the reaction device to the second heat transfer device; the side heat preservation components, top heat preservation components, and bottom heat preservation components are configured to maintain a stable thermal field for crystal growth.

[0006] The side insulation component includes a first insulation component and a second insulation component, with the second insulation component located outside the first insulation component and the top insulation component; the top insulation component includes a third insulation component and a fourth insulation component; the third insulation component is correspondingly provided to the top of the first insulation component and is detachably connected; the fourth insulation component is located on the side of the third insulation component away from the first insulation component. The first insulation component includes a multi-layered coaxial annular shielding cylinder, which is detachably installed on the outside of the reaction device; the vertical height of the multi-layered annular sidewalls decreases from the inside to the outside in the radial direction; the side of the multi-layered annular sidewalls with the same height and the second insulation component are detachably connected to the support device; the multi-layered coaxial annular shielding cylinder is set on the outside of the reaction device to ensure that the innermost shielding cylinder is not melted or deformed under the high temperature of the graphite carbon atmosphere. The support device is used to support the upper temperature control system; the first heat transfer device is located outside the reaction device and connected to the second heat transfer device; the second heat transfer device is used to balance the temperature of the upper temperature control system and the lower temperature control system to maintain stability.

[0007] In an optional embodiment, the first insulation component includes four coaxial annular shielding cylinders distributed at equal intervals, the vertical height of which decreases equidistantly from the inside to the outside in the radial direction; the innermost shielding cylinder is coated with an insulating layer, and its inner diameter is larger than the outer diameter of the first heat transfer device; the side of the first insulation component closest to the support device is located on the same horizontal plane and is detachably connected to the support device; the shielding cylinders are spaced equidistantly to ensure a uniform and symmetrical temperature field, and the height of each shielding cylinder decreases equidistantly from the inside to the outside.

[0008] The innermost shielding cylinder is coated with an insulating layer to ensure that it will not melt or deform under the high temperature of the graphite carbon atmosphere.

[0009] The third insulating element has a first stepped protrusion at its contact point with the first insulating element, corresponding to the side wall of the first insulating element; the third insulating element has a second stepped protrusion at its end near the fourth insulating element, corresponding to the third stepped protrusion on the fourth insulating element. The stepped protrusions facilitate a tighter fit between the insulating elements and reflect heat radiation, resulting in a more uniform and constant temperature inside the crucible and preventing air convection between the inside and outside of the reaction apparatus, thus enhancing the insulation effect.

[0010] In an optional embodiment, the top insulation component further includes a fifth insulation component and a sixth insulation component; the outer diameter of the fifth insulation component is equal to the inner diameter of the second insulation component, and the outer diameter of the sixth insulation component is equal to the outer diameter of the second insulation component, and it is located on top of the second insulation component. The third, fourth, fifth, and sixth insulation components each have a central hole, which is coaxially arranged. The seed crystal rod passes through the central hole and abuts against the reaction device. The diameter of the central hole decreases radially. Among them, the inner diameter of the central hole of the third insulation component is larger than the inner diameter of the central hole of the reaction device.

[0011] It should be noted that the fourth insulation component is made of porous insulation material, the fifth insulation component is made of multi-layer ceramic material or zirconium oxide material, and the sixth insulation component is made of molybdenum material.

[0012] Since the fifth insulation component is a multi-layered structure, with hollow columnar bodies connecting the layers, this design mainly creates and maintains a vacuum environment inside the fifth insulation component to completely eliminate heat convection and greatly reduce heat conduction.

[0013] In an optional embodiment, the reaction apparatus includes a crucible, and the first heat transfer device includes a heating element; the crucible is located inside the heating element, and the heating element is located inside the innermost shielding cylinder; The crucible includes a crucible wall, a crucible bottom, and a fixing groove; the crucible wall and the crucible bottom are integrally formed, and the crucible bottom is located between the crucible wall and the fixing groove; wherein, the crucible wall is a cylindrical body of equal diameter; the crucible bottom is an inverted cone shape, and the axial diameter decreases from the crucible wall to the fixing groove; a detachable filter element is provided axially at the connection between the crucible bottom and the crucible wall; the seed crystal rod and the fixing groove are always in a straight line, and the fixing groove passes through and connects the first heat transfer device and the second heat transfer device.

[0014] In an optional implementation, the seed crystal rod can also be connected to an external heating device. By regulating the temperature state of the seed crystal, the temperature difference with the melt can be reduced, effectively reducing thermal shock; eliminating internal residual stress and inhibiting growth cracking, which can effectively reduce the defects that the seed crystal may warp or break due to uneven thermal expansion, or even cause the crystal growth to be interrupted, thus promoting high-quality crystal growth.

[0015] In an optional embodiment, the crucible is a molybdenum crucible, which is an axisymmetric crucible; its material can be reasonably adjusted according to actual needs; in the embodiments of this application, a Y2O3 coating is applied to the inner wall of the molybdenum crucible, which can act as a physical barrier to isolate the molybdenum crucible from the melt, prevent the crucible from reacting with the melt, and the wettability of yttrium oxide with YAG melt is good, and the coefficient of thermal expansion is more matched with YAG crystal, which can reduce the stress between the melt and the crucible wall, improve the interface characteristics, reduce defects caused by interface reaction or thermal stress during crystal growth, and improve crystal integrity.

[0016] The connection method between the filter element and the crucible can be set according to the actual situation, such as snap-fit ​​connection, threaded connection, etc.; the material of the filter element is the same as that of the crucible to avoid introducing new impurities and contaminating the crystal during the crystal growth process.

[0017] In an optional embodiment, the heating element is a graphite cylinder heating element, located between the innermost shielding cylinder and the crucible wall, and is detachably installed with the support device; the graphite cylinder heating element has a plurality of first grooves with equal spacing on the side near the bottom of the crucible, and a plurality of second grooves with equal spacing on the side away from the bottom of the crucible, and the plurality of first grooves and the plurality of second grooves form an electrical circuit. It should be noted that, in the embodiments of this application, the first groove has eight openings and the second groove has six openings, which are respectively connected to the positive and negative terminals of the power supply to form a rectangular wave-shaped slat power circuit.

[0018] The first heat transfer device further includes a crucible positioning element, a first heat transfer element, and a second heat transfer element; the crucible positioning element is located outside the fixing groove, passes through the first heat transfer element, and abuts against the second heat transfer element; in the embodiments of this application, the crucible positioning element is made of molybdenum, the first heat transfer element is made of zirconium oxide, and the second heat transfer element is made of molybdenum.

[0019] To prevent the crucible from tilting or falling over, the crucible positioning component, the first heat transfer component, and the second heat transfer component are tightly fitted together. Specifically, the first heat transfer component has a first annular protrusion on the side near the second heat transfer component, and the second heat transfer component has a first annular groove corresponding to the first annular protrusion, a second annular groove corresponding to the crucible positioning component, and a heat transfer groove connected to the second heat transfer device; the vertical height of the first annular groove is higher than the vertical height of the second annular groove.

[0020] The crucible positioning component forms a channel with a certain thermal conductivity with the water-cooled crucible component through a heat transfer groove. The water-cooled crucible rod can move up and down along the axial direction to adjust the position of the crucible appropriately. In order to enhance the heat preservation of the bottom of the crucible and generate a certain amount of heat conduction, while preventing the airflow from impacting the fixing groove at the bottom of the crucible and causing crystal cracking, the diameter of the first heat transfer component made of zirconia is approximately the same as that of the fixing groove at the bottom of the crucible.

[0021] In an optional embodiment, the first heat transfer device further includes an electrode plate and a water-cooled electrode; the second heat transfer element also has a second annular protrusion. The electrode plate is a symmetrical electrode plate, and a third annular groove corresponding to the second annular protrusion is formed in the center of the electrode plate; the second annular protrusion passes through the third annular groove and is connected to the second heat transfer device. Along the axial direction of the electrode plate near the second heat transfer element, a fourth annular groove and a fifth annular groove are formed from the inside to the outside, which are connected to the support device; wherein, the fourth annular groove is also connected to the heating element; It should be noted that a first support is also placed on the outside of the heating element. The inner diameter of the fourth annular groove is larger than the inner diameter of the bottom of the groove. The first support that matches it is also a trapezoidal structure. The trapezoidal first support abuts against the crucible wall. During assembly, its smaller diameter side is located at the bottom of the groove, and its larger diameter side is located at the opening of the groove. To ensure the stability of the heating element, in the embodiment of this application, the length of the larger diameter side of the trapezoidal structure of the second support is greater than the inner diameter of the opening of the fourth annular groove.

[0022] In an optional implementation, a fastener can be used to detachably connect the first support member and the heating element. The specifications and types of the fastener can be adjusted reasonably according to actual needs, such as bolts, rivets, and clips.

[0023] The electrode plate has symmetrical electrode holes on the outside of the fifth annular groove. The water-cooled electrode passes through the electrode holes and is detachably connected to the electrode plate.

[0024] The heating element, the first heat transfer device, and the second heat transfer device are electrically connected.

[0025] In an optional embodiment, the support device includes a first support member, a second support member, and a third support member. The first support member corresponds to the fourth annular groove and is located outside the heating element, supporting and fixing the heating element to prevent it from tilting or falling over. The second support member corresponds to the fifth annular groove and is made of insulating material, which can effectively prevent heat loss and ensure that the temperature inside the reaction device remains stable. The third support member is located on top of the second support member and is used to support the side insulation element.

[0026] Specifically, the third support member has a first insulation groove and a second insulation groove on the side near the side insulation member, which are respectively corresponding to the first insulation member and the second insulation member. The first insulation groove and the second insulation groove are set at equal intervals.

[0027] In an optional embodiment, the second heat transfer device includes a water-cooled crucible component that penetrates the bottom insulation component and abuts against a heat transfer groove formed in the second heat transfer component; the second heat transfer device, the bottom insulation component, and the water-cooled electrode are located on the same horizontal plane; the water-cooled crucible component and the water-cooled electrode work together to regulate the temperature of the large-size YAG crystal growth system to maintain a constant temperature, and the crystal growth is stable.

[0028] The second heat transfer device is at the same vertical height as the bottom insulation component, and it abuts against the side of the electrode plate away from the upper temperature control system. The bottom insulation component includes an internal insulation component that abuts against the second heat transfer device and an external insulation component that wraps around the outside of the internal insulation component. The internal insulation component is composed of multiple layers of molybdenum sheets, and the external insulation component is a corundum insulating support ring. It abuts against the electrode plate, the internal insulation component, and the second heat transfer device, and tightly wraps the second heat transfer device. It not only supports the electrode plate but also prevents air convection, further improving the insulation effect of the large-size YAG crystal growth system.

[0029] The water-cooled electrode is located on the outside of the bottom insulation component; the water-cooled electrode is connected to the electrode plate through a fastener; the fastener can be selected according to actual needs, such as bolts, rivets, clips, etc.

[0030] In an optional implementation, the large-size YAG crystal growth system also includes a temperature sensor, a heating device, a vacuum pumping device, and a control device. The temperature sensor is located in the second annular groove of the second heat transfer element and is used to detect temperature changes in the reaction device. This facilitates temperature regulation by the control equipment, ensures uniform heat field distribution, stability and consistency of the crystal growth process, and reduces crystal growth defects.

[0031] The heating equipment provides a heat source for the large-size YAG crystal growth system; the vacuum equipment evacuates the large-size YAG crystal growth system and fills it with inert gas; the control equipment is used to regulate the temperature changes during the operation of the large-size YAG crystal growth system.

[0032] This utility model has the following beneficial effects: This invention provides a large-size YAG crystal growth system based on a resistance furnace. By employing a three-segment independent axial temperature control system, it facilitates precise control of the multi-layer gradient temperature field, significantly reducing crystal cracking caused by excessive stress during crystal growth and substantially improving the growth quality and production efficiency of large-size YAG crystals. Precise temperature control and dynamic adjustment using a PID algorithm ensure that the performance of the generated large-size YAG crystals is comparable to that of crystals grown in traditional induction furnaces, guaranteeing high purity and uniformity. Furthermore, it successfully achieves stable mass production of YAG crystals with diameters greater than φ60mm, demonstrating high practical value. This system not only improves the growth quality of large-size YAG crystals but also provides solid technical support for the manufacture of high-precision optical devices. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a large-size YAG crystal growth system; Figure 2 This is a schematic diagram of the third insulation component; Figure 3 This is a schematic diagram of the fourth insulation component; Figure 4 This is a schematic diagram of the crucible's structure; Figure 5 This is a schematic diagram of the crucible positioning component; Figure 6 This is a schematic diagram of the structure of the first heat transfer element; Figure 7 This is a schematic diagram of the structure of the second heat transfer element; Figure 8 This is a schematic diagram of the heating element. Figure 9 This is a schematic diagram of the electrode plate structure; Figure 10 This is a structural schematic diagram of the third support component.

[0035] Key component symbols: 1-Large-size YAG crystal growth system; 11-Upper temperature control system; 12-Middle temperature control system; 13-Lower temperature control system; 111-First insulation component; 113-Second insulation component; 115-Third insulation component; 1151-First stepped protrusion; 1152-Second stepped protrusion; 117-Fourth insulation component; 1171-Corresponding to the third stepped protrusion; 121-Fifth insulation component; 1211-Hollow columnar body; 123-Sixth insulation component; 125-Center hole of insulation component; 130-Crucible; 1301-Crucible wall; 1303-Crucible bottom; 1305-Fixing groove; 1307-Filter component; 140-Heating component; 1401-First groove; 1403-Second groove; 1405-Positive and negative electrode components; 150-Crucible Crucible positioning component; 1501-Crucible positioning component groove; 160-First heat transfer component; 1601-First annular protrusion; 170-Second heat transfer component; 1701-First annular groove; 1703-Second annular groove; 1705-Heat transfer groove; 1707-Second annular protrusion; 180-Electrode plate; 1801-Third annular groove; 1803-Fourth annular groove; 1805-Fifth annular groove; 1807-Electrode hole; 190-Water-cooled electrode; 1901-Fixing component; 200-First support component; 210-Second support component; 230-Third support component; 2301-First insulation component groove; 2303-Second insulation component groove; 2305-Second support component groove; 250-Water-cooled crucible component; 260-Internal insulation component; 270-External insulation component. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0037] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0038] First Embodiment Please see Figure 1 This embodiment provides a large-size YAG crystal growth system 1 based on a resistance furnace, which includes an upper temperature control system 11, a middle temperature control system 12 and a lower temperature control system 13.

[0039] The upper temperature control system 11 includes a reaction device and a heat preservation device, the heat preservation device including side heat preservation components and a top heat preservation component; the middle temperature control system 12 includes a support device and a first heat transfer device; the lower temperature control system 13 includes a second heat transfer device and a bottom heat preservation component; the first heat transfer device connects the reaction device to the second heat transfer device; the side heat preservation components, top heat preservation components, and bottom heat preservation components are configured to maintain a stable thermal field for crystal growth. The specific structure is as follows: The side insulation component includes a first insulation component 111 and a second insulation component 113, with the second insulation component 113 located outside the first insulation component 111 and the top insulation component. The second insulation component 113 is made of stainless steel and serves as a heat shielding element in the low-temperature zone, while the first insulation component 111 is made of molybdenum and serves as a heat radiation shielding element in the high-temperature zone.

[0040] The first insulation component 111 includes four coaxial annular shielding tubes with equal spacing, whose vertical height decreases equidistantly from the inside to the outside in the radial direction; the side of the first insulation component 111 closest to the support device is located on the same horizontal plane; specifically, the side with equal height of the multi-layer annular sidewalls and the second insulation component 113 are detachably connected to the third support component 230 in the support device; four coaxial annular shielding tubes are set outside the reaction device, and the height of each shielding tube decreases equidistantly from the inside to the outside in a stepped manner, and the equidistant spacing between each shielding tube is set to ensure that the temperature field distribution inside the reaction device is symmetrical and uniform.

[0041] To ensure that the innermost shielding cylinder does not melt or deform under the high temperature of the graphite carbon atmosphere, this embodiment has a tungsten sheet lining the innermost layer of the shielding cylinder.

[0042] The innermost shielding cylinder has an inner diameter larger than the outer diameter of the heating element 140 in the first heat transfer device. An insulating layer of Y2O3 is coated on the inner side of the innermost shielding cylinder, which can act as a physical barrier to prevent the molybdenum crucible 130 from contacting the melt and prevent the crucible 130 from reacting with the melt. Yttrium oxide has good wettability with YAG melt and its coefficient of thermal expansion is more compatible with YAG crystal, which can reduce the stress between the melt and the crucible wall 1301, improve interface characteristics, reduce defects caused by interface reaction or thermal stress during crystal growth, and improve crystal integrity.

[0043] Please see Figure 1 , Figure 2 and Figure 3 The top insulation component includes the third insulation component 115 to the sixth insulation component 123, wherein the third insulation component 115 (see Figure 2 The fourth insulation component 117 is correspondingly and detachably connected to the top of the first insulation component 111; Figure 3 The third insulation component 115 is located on the side away from the first insulation component 111; it is located inside the first insulation component 111; the outer diameter of the fifth insulation component 121 is equal to the inner diameter of the second insulation component 113, and the outer diameter of the sixth insulation component 123 is equal to the outer diameter of the second insulation component 113, and it is located on top of the second insulation component 113.

[0044] The third insulation component 115, the fourth insulation component 117, the fifth insulation component 121, and the sixth insulation component 123 are each provided with a central hole, referred to as the central hole 125. The central holes 125 are coaxially arranged, and the seed crystal rod (not shown in the figure) passes through the central hole 125 and abuts against the fixing groove 1305 in the reaction device. The diameter of the central hole 125 decreases radially from the third insulation component 115 to the sixth insulation component 123. Among them, the inner diameter of the central hole 125 of the third insulation component 115 is larger than the inner diameter of the central hole of the reaction device.

[0045] It should be noted that the fourth insulation element 117 is made of porous insulation material, serving as the upper insulation shielding element; it is lightweight and has good insulation performance. The fifth insulation element 121 is made of multi-layer ceramic or zirconium oxide material, and the sixth insulation element 123 is made of molybdenum material. Furthermore, the layers of the fifth insulation element 121 are connected by hollow columnar bodies 1211. This arrangement primarily creates and maintains a vacuum environment inside the fifth insulation element 121 to completely eliminate heat convection and significantly reduce heat conduction.

[0046] The third insulating element 115 has a first stepped protrusion 1151 at its contact point with the first insulating element 111, corresponding to the side wall of the first insulating element 111. The third insulating element 115 has a second stepped protrusion 1152 at its end near the fourth insulating element 117, corresponding to the third stepped protrusion 1171 on the fourth insulating element 117. The stepped protrusions facilitate a tighter contact between the insulating elements and reflect heat radiation, resulting in a more uniform and constant temperature within the crucible 130. This prevents air convection between the inside and outside of the reaction apparatus, thus enhancing the insulation effect.

[0047] Please see Figure 1 and Figure 4 The reaction apparatus includes a crucible 130, which is located inside a heating element 140, which is located inside the innermost shielding cylinder. The crucible 130 includes a crucible wall 1301, a crucible bottom 1303, and a fixing groove 1305. The crucible wall 1301 and the crucible bottom 1303 are integrally formed to ensure the sealing and uniformity of the melt. The crucible wall 1301 is a cylindrical body of equal diameter, and its vertical height is less than the vertical height of the heating element 140, meaning the crucible 130 is located inside the heating element 140. The crucible bottom 1303 is located between the crucible wall 1301 and the fixing groove 1305, and the crucible bottom 1303 is rounded. The crucible is tapered, with its axial diameter decreasing from the crucible wall 1301 to the fixing groove 1305. A detachable filter element 1307 is axially provided at the connection between the crucible bottom 1303 and the crucible wall 1301. The filter element 1307 is connected to the crucible 130 in the following manner: a seed crystal rod passes through the crucible wall 1301 and the crucible bottom 1303 and abuts against the fixing groove 1305. The fixing groove 1305 is placed in the groove of the crucible positioning member 150 and passes through the first heat transfer member 160 and connects to the second heat transfer member 170.

[0048] Please see Figure 1 , Figure 5 , Figure 6 and Figure 7 The fixing groove 1305 is located inside the crucible positioning member 150, corresponding to the crucible positioning member groove 1501. The fixing groove 1305 penetrates the first heat transfer member 160 and abuts against the second heat transfer member 170. The crucible positioning member 150 is made of molybdenum, the first heat transfer member 160 is made of zirconium oxide, and the second heat transfer member 170 is made of molybdenum, all of which have thermal conductivity. It should be noted that, in this embodiment, in addition to heat transfer, the first heat transfer member 160 and the second heat transfer member 170 also provide support and fixation for the crucible 130. Specifically, the first heat transfer member 160 directly fixes the crucible 130, while the second heat transfer member 170 abuts against the crucible positioning member 150, indirectly fixing the crucible 130. This is a double-layer fixing mode. That is, the crucible positioning member 150, the first heat transfer member 160, and the second heat transfer member 170 are closely fitted together, further enhancing the stability of the reaction device and effectively preventing the crucible 130 from tilting or falling over.

[0049] Among them, the crucible positioning component 150 is made of molybdenum and is used for heat transfer at the bottom 1303 of the crucible; the first heat transfer component 160 is made of zirconium oxide and is used for heat preservation at the bottom 1303 of the crucible, while also providing support for the fixing groove 1305; the second heat transfer component 170 is made of molybdenum and accelerates heat transfer at the bottom.

[0050] The external heating device for the seed crystal rod in this embodiment can effectively reduce thermal shock by regulating the temperature state of the seed crystal and reducing the temperature difference with the melt; it can also eliminate internal residual stress and inhibit growth cracking, thereby effectively reducing the defects that may occur when the seed crystal warps or breaks due to uneven thermal expansion, or even cause the crystal growth to be interrupted, which is conducive to high-quality crystal growth.

[0051] Please see Figure 1 and Figure 8 The heating element 140 is located between the innermost shielding cylinder and the crucible 130. The heating element 140 is a graphite cylinder heating element 140, which abuts against the first support member 200 and is installed together with the electrode plate 180 in the fourth annular groove 1803. The graphite cylinder heating element 140 has eight equally spaced first grooves 1401 on the side near the bottom of the crucible 1303 and six equally spaced second grooves 1403 on the side away from the bottom of the crucible 1303. Positive and negative electrode members 1405 are provided on the side of the first groove 1401 near the electrode plate 180 for connecting the positive and negative electrodes of the power supply. The multiple first grooves 1401 and the multiple second grooves 1403 are respectively connected to the positive and negative electrodes of the power supply to form a rectangular wave-shaped slat power circuit.

[0052] Please see Figure 6 and Figure 7 The first heat transfer element 160 has a first annular protrusion 1601 on the side near the second heat transfer element 170. The second heat transfer element 170 has a first annular groove 1701 corresponding to the first annular protrusion 1601, a second annular groove 1703 corresponding to the crucible positioning element 150, a heat transfer groove 1705 connected to the second heat transfer device, and a second annular protrusion 1707 corresponding to the third annular groove 1801 opened at the center of the electrode plate 180. The vertical height of the first annular groove 1701 is higher than the vertical height of the second annular groove 1703. That is, the first heat transfer element 160 corresponds to the first annular groove 1701, and the crucible positioning element 150 corresponds to the second annular groove 1703, which further strengthens the fixation of the crucible 130.

[0053] It should be noted that the outer diameter of the second annular protrusion 1707 is smaller than the inner diameter of the central hole of the electrode plate 180, which facilitates its axial up-and-down movement inside the central hole of the electrode plate 180; the outer diameter of the second heat transfer element 170 is larger than the inner diameter of the bottom insulation element and the inner insulation element 260. This setting can effectively ensure that the temperature field inside the reaction device remains constant and reduce air convection with the outside.

[0054] Please see Figure 1 and Figure 9 The first heat transfer device also includes an electrode plate 180 and a water-cooled electrode 190. The electrode plate 180 is composed of two independent and symmetrical electrode plates 180. The center of the electrode plate 180 is provided with a third annular groove 1801 corresponding to the second annular protrusion 1707. It should be noted that the third annular groove 1801 is the center hole of the electrode plate 180 formed by the symmetrical assembly of the two electrode plates 180. Its inner diameter is larger than the outer diameter of the second heat transfer element 170, which facilitates the up and down movement of the water-cooled crucible 250, the first heat transfer element 160 and the second heat transfer element 170 in the axial direction.

[0055] The second annular protrusion 1707 passes through the third annular groove 1801 and connects to the second heat transfer device. On the side of the electrode plate 180 near the second heat transfer element 170, in the axial direction, a fourth annular groove 1803 and a fifth annular groove 1805 are formed from the inside out, connecting to the support device. The electrode plate 180 has symmetrical electrode holes 1807 on the outer side of the fifth annular groove 1805. The water-cooled electrode 190 passes through the electrode holes 1807 and is detachably connected to the electrode plate 180. In this embodiment, the fixing component 1901 is a bolt.

[0056] It should be noted that the inner diameter of the fourth annular groove 1803 is larger than the inner diameter of the bottom of the groove, and the first support 200 that is matched and assembled with it is also a trapezoidal structure. The trapezoidal first support 200 abuts against the crucible wall 1301. During assembly, the side with the smaller diameter is located at the bottom of the groove, and the side with the larger diameter is located at the opening of the groove. In order to ensure the stability of the heating element 140, the length of the larger diameter side of the trapezoidal structure of the second support 210 is greater than the inner diameter of the opening of the fourth annular groove 1803.

[0057] Please see Figure 1 and Figure 10 The support device includes a first support member 200, a second support member 210 and a third support member 230. The first support member 200 corresponds to the fourth annular groove 1803 and is located outside the heating element 140. The second support member 210 corresponds to the fifth annular groove 1805. The third support member 230 is located on top of the second support member 210 and is used to support the side insulation element.

[0058] Specifically, the second support groove 2305 and the fifth annular groove 1805 are respectively provided, and the two ends of the second support 210 abut against the third support 230 and the electrode plate 180 respectively.

[0059] The third support member 230 has a first insulation groove 2301 and a second insulation groove 2303 on the side near the side insulation member, corresponding to the first insulation member 111 and the second insulation member 113 respectively. The first insulation groove 2301 and the second insulation groove 2303 are equally spaced. There are four first insulation grooves 2301, which correspond to four layers of coaxial annular shielding cylinders.

[0060] The second heat transfer device includes a water-cooled crucible 250, which penetrates the bottom insulation and abuts against the heat transfer groove 1705 opened in the second heat transfer device 170; the second heat transfer device, the bottom insulation and the water-cooled electrode 190 are located on the same horizontal plane; the water-cooled crucible 250 and the water-cooled electrode 190 cooperate to regulate the temperature of the large-size YAG crystal growth system 1 to maintain a constant temperature, and the crystal growth is stable.

[0061] The water-cooled crucible rod can move up and down along the axial direction to adjust the position of the crucible 130 appropriately. In order to enhance the heat preservation of the crucible bottom 1303 and generate a certain amount of heat conduction, and to prevent the airflow from impacting the fixing groove 1305 of the crucible bottom 1303 and causing crystal cracking, the diameter of the first heat transfer element 160 made of zirconia is approximately the same as that of the fixing groove 1305 of the crucible bottom 1303.

[0062] The second heat transfer device and the bottom insulation component are at the same vertical height and respectively abut against the side of the electrode plate 180 away from the upper temperature control system 11. The bottom insulation component includes an inner insulation component 260 that abuts against the second heat transfer device and an outer insulation component 270 that wraps around the inner insulation component 260. The inner insulation component 260 is composed of multiple layers of molybdenum sheets, and the outer insulation component 270 is a corundum insulating support ring. It abuts against the electrode plate 180, the inner insulation component 260 and the second heat transfer device, and tightly wraps the second heat transfer device. It not only supports the electrode plate 180, but also prevents air convection, further improving the heat preservation effect of the large-size YAG crystal growth system 1.

[0063] It should be noted that the inner diameter of the internal insulation component 260 is smaller than the inner diameter of the central hole of the electrode plate 180, but larger than the second annular protrusion 1707 in the second heat transfer component 170, which is beneficial to maintaining a constant temperature field inside the reaction device.

[0064] Furthermore, the large-size YAG crystal growth system 1 provided in this embodiment also includes a temperature sensor, a heating device, a vacuuming device, and a control device. The temperature sensor is located in the second annular groove 1703 of the second heat transfer element 170 and is used to detect temperature changes in the reaction device. This facilitates temperature regulation by the control device, ensuring uniform heat distribution, stability and consistency of the crystal growth process, and reducing crystal growth defects. The heating device provides a heat source for the large-size YAG crystal growth system 1; the vacuuming device evacuates the large-size YAG crystal growth system 1 and fills it with inert gas; the control device is used to regulate temperature changes during the operation of the large-size YAG crystal growth system 1.

[0065] First Application Example This application example uses the large-size YAG crystal growth system 1 provided in the first embodiment to grow YAG crystals. It effectively solves the problems of large temperature fluctuations and severe impurity contamination in traditional growth processes, significantly improving the growth quality and production efficiency of large-size YAG crystals. Through precise temperature control and dynamic adjustment using a PID algorithm, as well as reasonable parameter settings, the temperature fluctuations during crystal growth are effectively controlled within ±0.5℃, and the impurity contamination rate is reduced to below 0.1%, ensuring high purity and uniformity of the crystals. This results in large-size YAG crystals with a diameter greater than 50mm and a uniform diameter length greater than 120mm.

[0066] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A large-size YAG crystal growth system based on a resistance furnace, characterized in that, The large-size YAG crystal growth system is an axially independent three-section temperature control system, including an upper temperature control system, a middle temperature control system, and a lower temperature control system; The upper temperature control system includes a reaction device and a heat preservation device, the heat preservation device including side heat preservation components and top heat preservation components; the middle temperature control system includes a support device and a first heat transfer device; the lower temperature control system includes a second heat transfer device and a bottom heat preservation component; the first heat transfer device connects the reaction device to the second heat transfer device. The side insulation component includes a first insulation component and a second insulation component, the second insulation component being located outside the first insulation component and the top insulation component; the top insulation component includes a third insulation component and a fourth insulation component; the third insulation component is correspondingly disposed to the top of the first insulation component and is detachably connected; the fourth insulation component is located on the side of the third insulation component away from the first insulation component. The first insulation component includes a multi-layer coaxial annular shielding cylinder, which is detachably installed on the outside of the reaction device; the vertical height of the multi-layer coaxial annular shielding cylinder decreases from the inside to the outside in the radial direction; one side of the multi-layer annular sidewall with the same height and the second insulation component are detachably connected to the support device respectively. The supporting device is used to support the upper temperature control system; the first heat transfer device is located outside the reaction device and connected to the second heat transfer device; the second heat transfer device is used to balance the temperature of the upper temperature control system and the lower temperature control system to maintain stability.

2. The large-size YAG crystal growth system according to claim 1, characterized in that, The first insulation component includes four coaxial annular shielding cylinders with equal spacing, whose vertical height decreases equally from the inside to the outside in the radial direction; the innermost shielding cylinder is coated with an insulating layer, and its inner diameter is larger than the outer diameter of the first heat transfer device; the side of the first insulation component closest to the support device is located on the same horizontal plane and is detachably connected to the support device. The third insulation component has a first stepped protrusion at the point where it abuts against the first insulation component, which corresponds to the side wall of the first insulation component; the third insulation component has a second stepped protrusion at the end near the fourth insulation component, which corresponds to the third stepped protrusion on the fourth insulation component.

3. The large-size YAG crystal growth system according to claim 1, characterized in that, The top insulation component also includes a fifth insulation component and a sixth insulation component; the outer diameter of the fifth insulation component is equal to the inner diameter of the second insulation component; the outer diameter of the sixth insulation component is equal to the outer diameter of the second insulation component and is located on top of the second insulation component; The third, fourth, fifth, and sixth insulating components each have a central hole, which are coaxially arranged. The seed crystal rod passes through the central hole and abuts against the reaction device. The diameter of the central hole decreases radially. The inner diameter of the central hole of the third insulating component is larger than the inner diameter of the central hole of the reaction device.

4. The large-size YAG crystal growth system according to claim 1, characterized in that, The reaction apparatus includes a crucible, and the first heat transfer device includes a heating element; the crucible is located inside the heating element, and the heating element is located inside the innermost shielding cylinder; The crucible includes a crucible wall, a crucible bottom, and a fixing groove; the crucible bottom is located between the crucible wall and the fixing groove; wherein, the crucible wall is a cylindrical body of equal diameter; the crucible bottom is an inverted cone shape, and the axial diameter decreases from the crucible wall to the fixing groove; a detachable filter element is axially provided at the connection between the crucible bottom and the crucible wall; the seed crystal rod abuts against the fixing groove and is always on the same straight line as the fixing groove, passing through the first heat transfer device and connecting the second heat transfer device.

5. The large-size YAG crystal growth system according to claim 4, characterized in that, The heating element is a graphite cylinder heating element, located between the innermost shielding cylinder and the crucible wall, and is detachably installed with the support device; the graphite cylinder heating element has a plurality of first grooves with equal spacing on the side near the bottom of the crucible, and a plurality of second grooves with equal spacing on the side away from the bottom of the crucible, and the plurality of first grooves and the plurality of second grooves form an electrical circuit. The first heat transfer device further includes a crucible positioning element, a first heat transfer element, and a second heat transfer element; the crucible positioning element is located outside the fixing groove, passes through the first heat transfer element, and abuts against the second heat transfer element; The first heat transfer element has a first annular protrusion on the side near the second heat transfer element, and the second heat transfer element has a first annular groove corresponding to the first annular protrusion, a second annular groove corresponding to the crucible positioning element, and a heat transfer groove connected to the second heat transfer device; the vertical height of the first annular groove is higher than the vertical height of the second annular groove.

6. The large-size YAG crystal growth system according to claim 5, characterized in that, The first heat transfer device further includes an electrode plate and a water-cooled electrode; the second heat transfer element also has a second annular protrusion. The electrode plate is a symmetrical electrode plate, and a third annular groove corresponding to the second annular protrusion is formed in the center of the electrode plate; the second annular protrusion passes through the third annular groove and is connected to the second heat transfer device. The electrode plate has a fourth annular groove and a fifth annular groove connected to the support device in the axial direction from the inside to the outside on the side close to the second heat transfer element; wherein, the fourth annular groove is also connected to the heating element. The electrode plate has symmetrical electrode holes on the outside of the fifth annular groove, and the water-cooled electrode passes through the electrode holes and is detachably connected to the electrode plate.

7. The large-size YAG crystal growth system according to claim 6, characterized in that, The support device includes a first support member, a second support member, and a third support member, wherein the first support member corresponds to the fourth annular groove and is located on the outside of the heating element; The second support member corresponds to the fifth annular groove; The third support is located on top of the second support and is used to support the side insulation component.

8. The large-size YAG crystal growth system according to claim 7, characterized in that, The third support member has a first insulation groove and a second insulation groove on the side near the side insulation member, which are respectively corresponding to the first insulation member and the second insulation member. The first insulation groove and the second insulation groove are set at equal intervals.

9. The large-size YAG crystal growth system according to claim 1, characterized in that, The second heat transfer device includes a water-cooled crucible component that penetrates the bottom insulation component and abuts against a heat transfer groove formed in the second heat transfer component; the second heat transfer device, the bottom insulation component, and the water-cooled electrode are located on the same horizontal plane; The second heat transfer device is at the same vertical height as the bottom insulation component, and respectively abuts against the side of the electrode plate away from the upper temperature control system; The bottom insulation component includes an inner insulation component that abuts against the second heat transfer device and an outer insulation component that wraps around the outside of the inner insulation component; The water-cooled electrode is located on the outside of the bottom insulation component.

10. The large-size YAG crystal growth system according to claim 1, characterized in that, The large-size YAG crystal growth system also includes temperature sensors, heating equipment, vacuum equipment, and control equipment. The temperature sensor is located in the second annular groove of the second heat transfer element and is used to detect temperature changes in the reaction device. The heating equipment provides a heat source for the large-size YAG crystal growth system; the vacuum equipment evacuates the large-size YAG crystal growth system and fills it with inert gas; the control equipment is used to regulate the temperature changes during the operation of the large-size YAG crystal growth system.

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