JP5754636B2 - Germanium melt molding method and apparatus - Google Patents

Description

  The present invention relates to a germanium melt molding method and apparatus, and more particularly to melt molding of germanium lenses and the like useful for infrared lenses and the like.

  Conventionally, for example, in Patent Document 1, a germanium lens for infrared measurement is manufactured by heating a germanium raw material to a melting point or higher, casting liquid germanium into a mirror-finished lens mold, and cooling the mold. . Moreover, in this thing, in order to prevent the penetration | invasion of an impurity, it is set as nitrogen gas atmosphere, Furthermore, the enclosed nitrogen gas is extracted and it is made a vacuum and air etc. are degas | defoamed from germanium liquid. Thereby, a germanium lens is shape | molded to a required shape at once.

  However, unlike other metals and glasses, germanium has a problem that its volume expands when solidified, causing cracks, swelling, and depression. Therefore, in Patent Document 2, germanium melt is injected into a mold at a high pressure and cooled while increasing the density. In the vicinity of the freezing point, the injection pressure is weakened to absorb the pressure of solidification expansion of the material to generate internal strain. The mold is melt-molded with a mold while increasing the injection pressure again below the freezing point. In addition, the temperature of the mold and the temperature in the heating furnace are measured with a temperature monitor to control the temperature. Further, a gas supply pipe is provided at the lower part of the mold, and a reducing gas is supplied to replace moisture and the like in the raw material powder.

JP-A 63-157754 JP 7-314123 A

  However, there is a problem that a stable shape cannot always be secured even when high-pressure injection is performed. This is because, when germanium solidifies, the crystal does not progress uniformly at the forming site, the starting point of the crystal is not constant, and the germanium melt cannot be expected to have fluidity, The flow due to expansion during solidification is slight and difficult to fit into the mold shape. For this reason, even if high-pressure injection is performed, it is considered that thermal expansion at the freezing point cannot be prevented, and cracks, swelling, and depression are still generated. Moreover, in order to counter the expansion during solidification, a large mold clamping device is required, and there is a problem that the entire device is large and expensive. Although temperature control is performed by a temperature monitor, detailed temperature distribution, state, and change are not mentioned. Moreover, although reducing gas is supplied, it is only used for replacement, and there is no mention of cooling.

  In view of such problems, the object of the present invention is to control the expansion of germanium at the freezing point, or to escape in a direction that does not affect the molding shape. It is an object to provide a germanium melt molding method and apparatus with fewer steps. Another object is to eliminate the need for a large mold clamping device or the like and reduce the overall size of the device. Furthermore, it is to provide a more preferable temperature control, cooling method and apparatus.

In the present invention, a solid germanium raw material is placed in a lower mold constituting a mold in an inert gas atmosphere, the germanium raw material is melted by controlling the heating of the mold from the outside, and the molding is performed. After each temperature of the upper mold and the lower mold constituting the mold reaches a temperature higher than the melting point of germanium, the upper mold is lowered to be brought into contact with the lower mold, and then an inert gas is used. the outwardly from the central portion of the upper and lower molds solidifying the germanium thereby gradually cooling the upper and lower molds, also continues the cooling of the mold after solidification of the germanium has been completed, and the The above- described problems were solved by providing a germanium melt molding method for lowering the temperature of the upper and lower molds and molding the germanium raw material.

  That is, in the solidification process in the mold after the germanium is melted, the entire mold (mold) containing the molten germanium is not cooled uniformly or naturally, but cooling is started from one or more parts. Then, the starting point of solidification of germanium is controlled by gradually extending the cooling range to the whole. By maintaining the external ambient temperature of the mold at a relatively high temperature, the cooling distribution and cooling rate are stabilized. As a result, the start of solidification is stabilized, and solidification is gradually performed from the portion to the whole so as to fit the mold. When solidification is completed, the heating device is turned off, and the mold, germanium (material), and the entire device are cooled to obtain a germanium molded product. Needless to say, the external ambient temperature is set to a temperature or a calorific value at which germanium in the mold can be solidified by cooling the mold.

  While conducting various experiments, the inventors of the present application measured the temperature near the inside of the mold during cooling of germanium, but the temperature that had dropped near the freezing point increased to some extent due to latent heat. After that, it was discovered that the temperature had fallen again. When the external ambient temperature is also decreasing at the same time, the disturbance was largely overlooked.However, as in the present invention, this was achieved by keeping the external ambient temperature constant, cooling only the mold, and measuring the mold internal temperature. I think that the phenomenon was confirmed. Such knowledge can identify the completion of the solidification of germanium.

Therefore, in the invention according to claim 2, the completion of the solidification is the completion of the cooling , the temperature in the upper and lower molds starts decreasing, the temperature starts increasing again, and then the upper and lower molds again. the temperature of the inner has a melt molding method germanium to complete when turned to descend.

In the invention described in claim 3, the cooling of the mold is continued with the germanium melt molding method in which the external heating is stopped and cooling is performed only with the inert gas .

A lens or the like is useful as a germanium molded product. Therefore, in the invention described in claim 4 , a germanium melt molding method is used in which the molding mold has a lens shape .

As a more specific method, in the invention described in claim 5, the shape in the mold is formed in said lower mold and a flat or convex of the upper mold of the concave after the germanium melt, the upper the mold was melt molding method germanium releasing the excess material with molding is fitted to the lower mold.

  By using a concave lower mold, a germanium melt is stored. By using a flat or convex upper mold, germanium is filled in the mold during mold clamping. The germanium melt can also be kept in a state of swelling from the edge surface of the lower mold due to surface tension, and the inner mold shape of the upper mold may be slightly concave. In addition, when mold matching or clamping is performed from a molten state, or due to expansion during solidification, the volume increases and surplus raw materials are generated, so that surplus raw materials are allowed to escape.

A device for carrying out such a germanium melt molding method may be added with a mold partial cooling device in contrast to the conventional device. Therefore, in the invention described in claim 6 , a germanium melt molding apparatus provided in an inert gas atmosphere, comprising a lower mold having an upward concave mold surface into which a germanium raw material is placed, and a downward mold surface. An upper mold having a relief portion provided at an edge of the mold surface of the upper mold or the lower mold, and close to the mold surface of the upper mold or the lower mold inside the upper mold or the lower mold An upper mold or lower mold temperature sensor, and an upper support member lid section and a lower support member lid section for fixing the upper mold and the lower mold by being positioned above and below the upper mold and the lower mold, respectively. A moving device for contacting or separating the upper die and the lower die, a heating device provided around the upper die and the lower die, and a heating device temperature sensor for measuring the temperature of the heating device, At the center of the upper support member lid and the lower support member lid, Providing a molten molding apparatus of germanium the upper and cooling inert gas blowing port opening toward the lower die is provided.

  That is, an inert gas blowout port for cooling is provided for partial cooling of the mold so that the mold is partially cooled. In addition, the temperature sensor (monitor) is disposed in the upper mold or the lower mold in the vicinity of the upper mold surface or the lower mold surface so that a more accurate temperature can be measured. Furthermore, an escape portion is provided at the edge of the upper or lower mold surface so that the expansion of germanium during solidification is released outside the necessary mold surface of the mold.

In the present invention, since high-pressure clamping is not required, a material suitable for a germanium mold can be used even if the strength is low. We also want to make it easier to design the cooling inert gas passage. Therefore, in the invention according to claim 7 , the material of the upper mold and the lower mold is glassy carbon, and through the upper support member and the lower support member into which the upper mold and the lower mold are respectively inserted, A germanium melt molding apparatus connected to the moving apparatus was used.

In the present invention, in the solidification step in the mold after melting germanium, cooling is started from a portion, the cooling range is gradually widened, the start point of solidification of germanium is controlled, and the external ambient temperature is set. By maintaining a high temperature, the start of solidification is stabilized, and solidification that gradually fits the mold from the part to the whole is performed. In addition, after the solidification is completed, the heating device is turned off and cooling is performed only with an inert gas, and the temperature of the entire device is lowered to obtain a germanium molded product. There was no or little influence of time expansion, and there were no or few cracks, swelling, or depression.

Further, whether in the invention described in claim 2, the completion of coagulation, after the start of temperature drop is initiated the temperature rise again, since then again the temperature was completed when turned down, complete solidification where As a result, the solidification process is stabilized, the variation is small, the shape is stable, the accuracy is high, and the post-processing process is small.

In the invention according to claim 4, since the shape in the mold is a lens,
Lens molding is easy and there is little variation and accuracy is high. Furthermore, in the invention according to claim 5, the shape in the mold is a concave lower mold and a flat or convex upper mold, and after the germanium is melted in the lower mold, the upper mold is fitted to the lower mold and molded. In addition, since the surplus raw material is allowed to escape, the generation of burrs can be made on the outer peripheral side of the necessary part (lens part) of the molded product, and post-processing is easy. Further, even when mold matching or mold clamping is performed from a molten state, surplus raw materials are released, so that it is not necessary to perform excessive mold clamping, and the incidental equipment may be simple .

According to a sixth aspect of the present invention, in the germanium melt molding apparatus provided in the inert gas atmosphere, a cooling inert gas outlet is provided for partial cooling of the mold, and the mold is partially Cool down and place a temperature sensor (monitor) inside the mold close to the mold surface so that accurate temperature can be measured. In addition, a relief part is provided at the edge of the mold surface, and the expansion of germanium during solidification is molded. Therefore, a large mold clamping apparatus or the like is not required, the entire apparatus can be miniaturized, and a germanium melt molding apparatus capable of more preferable temperature control and cooling method is obtained.

Furthermore, in the invention described in claim 7, the mold material is glassy carbon, the mold material is movable through a support member into which the mold is inserted, and a cooling inert gas outlet is provided on the upper and lower support members side. A germanium melt molding apparatus is used.

  The upper and lower mold materials are made of glassy carbon and have a highly precise molding surface, and the cooling inert gas blowout and discharge openings are provided on the upper and lower support members where the upper and lower molds are inserted, making it easy to flow the cooling inert gas. Therefore, the molding accuracy is higher and the processing in the subsequent process is less.

It is a section explanatory view of a germanium melt molding device showing an embodiment of the present invention, and shows a state where an upper and lower mold contacts and germanium is melted. It is a time-temperature relationship figure which shows typically the temperature change of the melt-forming method of germanium which shows embodiment of this invention, a vertical axis | shaft is a Celsius temperature and a horizontal axis is elapsed time. It is an external appearance photograph of the lens molded article which shows embodiment of this invention. It is an external appearance photograph which shows the example of the molded article of the lens shape | molded by the conventional method.

  Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the germanium melt molding apparatus 1 is provided with upper and lower molds 3 and 4 and upper and lower support members 5 and 6 into which upper and lower molds are inserted in a hermetically insulated container 2 (hereinafter referred to as “sealed container”). It has been. The sealed container 2 is provided with an intake valve 9a for supplying an inert gas such as nitrogen, a gas inflow passage 7, an exhaust port 8 for exhausting the inert gas, and an exhaust valve 9b, which are connected to a gas source (not shown) and sealed. The inside of the container is an inert gas atmosphere. Moreover, it is insulated from the outside by a heat insulating material to improve thermal efficiency. The upper and lower molds 3 and 4 have a cylindrical shape with a collar, and the material thereof is glassy carbon. The lower mold 4 has an upward lens-shaped and concave mold surface 4b on the collar side (upper surface) 4a. Is supplied. A ring-shaped relief portion 4c is provided on the outer peripheral edge of the lower mold surface. The upper die 3 has a downwardly facing die surface 3b on the semi-finished side (lower surface) 3a. The mold surface 3b of the present embodiment is a flat surface.

  Glassy carbon, which is the material of the upper and lower molds 3 and 4, is used for carbon electrodes and the like, and its properties are hard and dense, and has a wide potential window in the oxidation direction and reduction direction, and is easy to use electrochemically. Alternatively, it is a black glassy carbon material excellent in chemical resistance, and is said to be excellent in heat resistance and small in surface roughness. In the present embodiment, glassy carbon (registered trademark) manufactured by Tokai Carbon Co., Ltd. was used as the glassy carbon. Needless to say, any material having similar properties can be used as appropriate without being limited to this material.

Upper and lower mold temperature sensors 11 and 12 are provided inside the upper mold 3 and the lower mold 4 close to the respective wall surfaces on the central axis c of the upper mold surface 3b and the lower mold surface 4b. Cylindrical portions 3e and 4e adjacent to the flanges 3d and 4d of the upper die 3 and the lower die 4 are the lower side stepped insertion holes 15a of the main body 15 of the upper support member 5 and the stepped upper side surface of the main body 16 of the lower support member 6, respectively. It is inserted in the insertion hole 16a. Ryotsuba unit 3d, 4d is stepped portion 15b of the lower end 25a and the upper end 26a and the body portion 15 of the lid portion 25, 26 of the top and bottom support members 5, 6 are clamped fixed between 16b, the upper and lower molds 3 and 4 The upper and lower support members 5 and 6 are fixed to the upper and lower support members, respectively.

  The upper support member 5 and the lower support member 6 are connected to rods 35a and 36a of pneumatic cylinders 35 and 36, which are moving devices, respectively. The pneumatic cylinder bodies 35b and 36b are respectively attached to the upper and lower sides outside the sealed container 2 by flanges 35c and 36c. A pneumatic cylinder and a control valve (not shown) are connected to the pneumatic cylinder, and the upper support member 5 and the upper mold 3 or the lower support member 6 and the lower mold 4 are movable in the vertical direction, and the upper mold and the lower mold are in contact with each other. Or it can be separated. The moving device may be a slide mechanism driven by a ball screw, a rack and pinion, or the like, in addition to the pneumatic cylinder.

  A gap 17 a is provided between the center portion 25 c of the lower surface 25 b of the upper support member lid portion 25 and the upper surface 3 f of the upper mold 3. A cooling inert gas outlet 18 a is opened in the gap 17 a at the center of the upper support member lid 25. The cooling inert gas outlet 18a is connected to a valve and an inert gas supply device (not shown) outside the sealed container 2 via a flexible hose 20a. Around the periphery of the cooling inert gas outlet 18a of the upper support member lid 25, the cooling inert gas discharge ports 19a are opened at four equal positions in the gap 17a, and the communication path 21a in the upper support member lid 25 is formed. And communicated with the inside of the sealed container 2.

  Similarly, a gap 17 b is provided between the center portion 26 c of the upper surface 26 b of the lower support member lid portion 26 and the lower surface 4 f of the lower mold 4. A cooling inert gas outlet 18b opens in the gap 17b at the center of the lower support member lid. The cooling inert gas outlet 18b is connected to a valve and an inert gas supply device (not shown) outside the sealed container 2 via a flexible hose 20b. Cooling inert gas outlets 19b are opened at four positions equally around the cooling inert gas outlet 18b of the lower support member lid 26, and the communication passage 21b in the lower support member lid 26 is formed in the gap 17b. And communicated with the inside of the sealed container 2.

  A heating device (heater) 22 is provided around the upper and lower molds with the position where the upper mold 3 and the lower mold 4 are in contact with each other so that the temperature of the upper and lower molds 3b and 4b exceeds the melting point of germanium. To be heated. Further, a heating device temperature sensor 23 for measuring the temperature inside the heating device is provided.

  Next, a germanium melt molding method using the germanium melt molding apparatus 1 will be described. For simplicity of explanation, the position of the lower mold 4 is fixed and only the upper mold 3 is moved up and down. In FIG. 1, first, when the upper mold is at the rising end position, an opening (not shown) of the sealed container 2 is opened, and a predetermined amount of germanium lump is placed in the mold 4 b of the lower mold 4. Next, the sealed container 2 is sealed, the exhaust valve 9b and the supply valve 9a are opened, nitrogen gas is sealed in the sealed container, and nitrogen gas is filled while expelling air. When the filling of nitrogen gas is completed, both valves 9a and 9b are closed. Next, the heating device 22 is operated, and heating is performed so that the temperature inside the heating device is higher than the germanium melting temperature (melting point: 939 ° C.) and a predetermined temperature of about 1050 ° C. (referred to as “heating step”). The predetermined temperature is appropriately set to a temperature or an amount of heat at which the temperature at the time of dissolution of germanium can be stably changed according to the size of the apparatus and the arrangement and size of the heating apparatus. FIG. 2 shows a qualitative one for explanation. Therefore, it is different from actual data.

  As shown by reference symbol A1 in FIG. 2, the temperature inside the heating device reaches a predetermined temperature with time, but the temperature rise in the upper and lower molds 3 and 4 is delayed as indicated by reference symbols B1 and C1. Furthermore, when the temperature in the lower mold 4 is equal to or higher than the melting point of germanium, dissolution of germanium starts. At this time, the temperature inside the heating device inner sensor 23 reaches a predetermined temperature and becomes constant as indicated by reference numeral A2, and the temperature of the temperature sensor 11 of the upper mold 3 continues to increase as indicated by reference numeral B2. However, as indicated by reference numeral C2-1, the temperature of the temperature sensor 12 of the lower mold 4 is level. After a certain time has elapsed, as indicated by reference numeral C2-2, the temperature of the temperature sensor 12 of the lower mold 4 starts to rise again (referred to as a “melting step”). This is considered that the heat of fusion at the time of dissolution of germanium is absorbed and the temperature rise is moderated or leveled, and after the dissolution is completed, the temperature rises again by heating of the heating device. The temperature of the lower mold temperature sensor starts to rise again from the same level, and the temperature of the lower mold temperature sensor varies depending on the capacity of the heating device and the like, but is 1000 ° C. or higher in the apparatus of the embodiment.

  After the melting of germanium is completed at the time when the temperature of the lower mold temperature sensor 12 starts to rise again from leveling out, after the melting of germanium is completed (actually, after the predetermined time indicated by reference numeral C2-3 has elapsed, or the lower mold temperature sensor The temperature of the heating device 22 and the upper and lower molds 3 and 4 are slightly higher than the melting point, as shown by reference signs A3, B3, and C3. The temperature is lowered to 950 ° C. to 960 ° C. (this is the same as in the present embodiment) so that the germanium 10 is in a stable state in a molten state (referred to as “melting stabilization step”).

  At this time, the liquid germanium 10 is melted in the lower mold 4 so as to rise from the mold inner surface 4b due to surface tension. At the same time or after the control temperature of the heating device 22 is lowered, the upper die 3 is lowered and brought into contact with the lower die 4. Thereby, the germanium 10 fills the upper and lower mold inner surfaces 3b and 4b. However, it does not reach to the filling portion 4c after solidification.

  Next, nitrogen gas at normal temperature (hereinafter referred to as “cooling gas”) as a cooling inert gas from a valve and an inert gas supply device (not shown) to the gaps 17a and 17b from the cooling inert gas outlets 18a and 18b. And forcibly cool the center of the upper and lower molds 3 and 4. The cooling gas is discharged into the sealed container 2 through the cooling inert gas discharge ports 19a, 19b communication paths 21a, 21b. Further, the exhaust valve 9b is opened, and the cooling gas is discharged to the outside through the exhaust port 8 and the exhaust valve 9b.

  As a result, the upper and lower molds 3 and 4 are gradually cooled outward from the center, and the germanium 10 in the upper and lower mold surfaces starts to solidify from the center (referred to as “solidification process”). At this time, as indicated by reference numeral A4, the heating device is controlled to maintain the stabilization temperature. On the other hand, germanium 10 reaches the solidification temperature lower than the melting temperature and solidifies, but the temperature of the upper and lower temperature sensors 11 and 12 does not continue to decrease, but from the decrease of reference BC4-1, reference to BC4-2 As shown in FIG. After that, again, as indicated by reference numeral BC4-3, it starts to move downward (925 ° C.). This time is defined as completion of solidification.

  After a predetermined time has elapsed after the temperature has been lowered, the heating device 22 is turned off while the supply of the cooling gas is continued, and the entire inside of the sealed container 2 is cooled as indicated by reference numerals A5 and BC5 ("cooling" Process)). When the temperature drops to room temperature or a handleable temperature, the supply of the cooling gas is stopped, the upper and lower molds 3 and 4 are opened, and the formed germanium molded product is taken out. The temperature described is a temperature measured in the embodiment, depends on the performance of the temperature sensor, the installation location, and the situation, and does not indicate a physically accurate temperature.

  Examples obtained by such an apparatus and method will be described. FIG. 3A is an external view photograph of the lens molded product created in the embodiment of the present invention. As shown in FIG. 3A, the lens molded product 50 has a lens body 51 and a burr 52. The lens body 51 has no bulge or defect, and has a shape along the upper and lower mold surfaces. Further, the surface roughness was also good, and it was an accuracy that could be used as a lens without post-processing as it was except for the burr part. The burr portion 52 is formed along the edge of the escape portion 4c. Since the burr 52 becomes an escape during solidification and eventually hardens, the surface roughness and shape are poor.

  FIG. 3B shows an example of an aspheric lens. In the lens molded product 53, as in the case of (a), the main body 54 is free of swelling and defects, and has good surface roughness and shape accuracy. The burr portion 55 is not the entire circumference of the lens but is gathered in one place and extends in a tongue shape and solidifies, and the shape is stable. The difference between (a) and (b) can be changed according to the amount of raw material and the shapes and capacities of the molds 3b and 4b and the escape portion 4c.

  On the other hand, in the case of cooling without the solidification step of the embodiment of the present invention, as shown in FIG. 4, the main body 61 of the lens 60 is swollen and the shape is bad so that it cannot be used as a lens at all. Moreover, the burr | flash part 62 generate | occur | produced in several places, and the place, the magnitude | size, and the extending direction were disperse | distributed, and it was in the state considered that unstable solidification was performed. Moreover, the variation of the molded product was large and a constant shape could not be obtained.

  In this way, as shown in the present embodiment, since the central portion can be cooled and solidified from the central portion to the entire solidification when germanium is solidified, there is no swelling, the shape is stable, and there is little variation. A germanium molded article can be obtained. In addition, the temperature of the mold temperature sensor is monitored, and after the temperature drops during the solidification process, the temperature rises again and the temperature when it starts to fall again can be determined as the completion of solidification during the solidification process, so control is also easy. , Making reproducibility easy, stabilizing the product and specifying the quality.

  Needless to say, each set temperature is appropriately set depending on the germanium raw material, the apparatus, the type and installation position of the temperature sensor, the shape of the mold, and the like. Moreover, although melting | fusing point was set to 939 degreeC in this embodiment, it is 937.4 degreeC in the cited reference 1, and 958.5 degreeC in the cited reference 2, and is not necessarily constant by each conditions, purity, etc. It is also difficult to measure accurate values of the melting point and the freezing point, and it is determined appropriately depending on the material and the apparatus. Further, the amount of the cooling gas is appropriately set depending on the arrangement of the heating device, the size of the mold, the arrangement, and the like. Further, the upper and lower molds are not limited to the same, and may be different or changed. The upper and lower molds have been described with respect to a single lens, but it goes without saying that the upper and lower molds can be applied to a plurality of lenses, a lens array, and the like.

1 Germanium melt molding equipment 3 Mold (upper mold)
3b Downward mold surface (inner mold inner surface)
4 Mold (Lower mold)
4b Upward concave mold surface (inside of mold)
4c Escape part 5 Upper support member 6 Lower support member 10 Germanium 11 Upper mold temperature sensor 12 Lower mold temperature sensors 18a and 18b Cooling inert gas outlets 19a and 19b Cooling inert gas outlet 23 Heating device (outside ambient) Temperature sensor 22 Heating device 36 Moving device c Center axis

Claims (7)

A solid germanium raw material is placed in a lower mold constituting a mold in an inert gas atmosphere, and the germanium raw material is melted by controlling the heating of the mold from the outside to form the mold. After each temperature of the mold and the lower mold becomes higher than the melting point of the germanium, the upper mold is lowered to be brought into contact with the lower mold, and then the upper mold and the lower mold using an inert gas. The germanium is solidified by gradually cooling the upper and lower molds outward from the center of the mold, and cooling of the mold is continued even after the solidification of the germanium is completed, and the temperature of the upper and lower molds is increased . A germanium melt molding method, wherein the germanium raw material is molded by lowering. The completion of the solidification, after starting the cooling start temperature is lowered in the upper and lower molds, is the temperature rise again started, the temperature of the subsequent in again said upper and lower molds is completed when the turned to descend The germanium melt molding method according to claim 1.
3. The germanium melt molding method according to claim 2 , wherein the cooling of the mold is continued only by the inert gas by stopping the external heating . Melt-molding method of the germanium of claim 3, wherein a shape in said mold is a lenticular. The shape of the mold is formed in said lower mold and a flat or convex of the upper mold of the concave after the germanium melt, to escape the surplus material with molding is fitted to the upper die to the lower die The method for melt forming germanium according to claim 4. An apparatus for melt forming germanium provided in an inert gas atmosphere, wherein a lower mold having an upward concave mold surface into which a germanium raw material is placed, an upper mold having a downward mold surface, and the upper mold or the lower mold Relief portion provided at the edge of the mold surface of the mold, and upper mold or lower mold temperature disposed inside the upper mold or the lower mold and close to the upper mold surface or the lower mold surface A sensor, an upper support member lid portion and a lower support member lid portion for fixing the upper die and the lower die by being positioned above and below the upper die and the lower die, and the upper die and the lower die are brought into contact with each other. Or a moving device for separating the heating device, a heating device provided around the upper die and the lower die, and a heating device temperature sensor for detecting the temperature of the heating device, and the upper support member lid portion and the lower support member lid At the center of each part, there is an opening toward the upper mold and the lower mold Melt forming apparatus germanium, characterized in that 却用 inert gas outlet are provided. The material of the upper mold and the lower mold is glassy carbon, and is connected to the moving device via an upper support member and a lower support member into which the upper mold and the lower mold are inserted, respectively. The germanium melt molding apparatus according to claim 6 .

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