Technological method for eliminating quartz glass stripes

Abstract

The invention provides a quartz glass stripe eliminating process method, which comprises: providing a quartz glass raw material and a groove sinking mold, the groove sinking mold having a central axis and a molding groove extending along the central axis; carrying out first liquid washing treatment on the quartz glass raw material; putting the quartz glass raw material subjected to the first liquid washing treatment into a forming tank, and performing first tank sinking treatment on the quartz glass raw material in a first pressure environment to obtain a first quartz glass piece; the side face, surrounding the central axis, of the first quartz glass piece just formed in the forming groove is set as an off-axis face, and cold machining treatment and second liquid washing treatment are sequentially conducted on the first quartz glass piece; the first quartz glass piece subjected to second liquid washing treatment is placed in a forming groove, the bottom wall of the forming groove supports the off-axis surface, and second groove sinking treatment is conducted on the first quartz glass piece in a second pressure environment; and repeating the last two steps until no obvious stripes exist on the first quartz glass piece, and obtaining a second quartz glass piece.

Description

Technical Field

[0001] This application relates to the field of quartz processing technology, and in particular to a process method for eliminating striations in quartz glass. Background Technology

[0002] The uneven temperature distribution inside quartz glass ingots often leads to uneven material distribution, resulting in microscopic differences in refractive index, which manifest as linear or banded structures, commonly known as "optical stripes." These optical stripes are clearly visible under polarized light or specific detection conditions, and can affect the performance of high-precision optical components. They may cause beam transmission distortion, uneven spot distribution, or introduce systematic errors, seriously affecting the performance of optical components. Summary of the Invention

[0003] This application provides a process for eliminating striations on quartz glass to solve the problem in the known art where optical striations on quartz glass affect the performance of optical components.

[0004] This application provides a process for eliminating striations in quartz glass, comprising the following steps: Quartz glass raw materials and a sinking mold are provided. The sinking mold has a defined central axis and a forming groove extending along the direction of the central axis. The quartz glass raw material is subjected to a first liquid washing treatment; The quartz glass raw material that has completed the first liquid washing treatment is placed in the forming tank, and the quartz glass raw material is subjected to a first tank sinking treatment under a first pressure environment. The first tank sinking treatment includes a first heating treatment, a second heating treatment, a first heat preservation treatment, a first cooling treatment, and a second cooling treatment performed in sequence to obtain a first quartz glass part. The side of the first quartz glass piece that has just been formed in the forming groove is set as the off-axis surface, and the first quartz glass piece is subjected to cold working treatment and second liquid washing treatment in sequence. The first quartz glass piece that has completed the second liquid washing treatment is placed in the forming tank, and the bottom wall of the forming tank supports the off-axis surface. The first quartz glass piece is subjected to a second tank sinking treatment under a second pressure environment. The second tank sinking treatment includes a third heating treatment, a fourth heating treatment, a second heat preservation treatment, a third cooling treatment, and a fourth cooling treatment performed in sequence. Repeat the last two steps above until there are no obvious streaks on the first quartz glass piece, and obtain the second quartz glass piece.

[0005] In one possible implementation, the first heating process involves heating the quartz glass raw material to 1000 to 1500°C at a rate of 10 to 20°C / min, the second heating process involves heating the quartz glass raw material to 1900 to 2000°C at a rate of 5 to 10°C / min, and the first heat preservation process involves holding the quartz glass raw material at 1900 to 2000°C for 4 to 8 hours.

[0006] In one possible implementation, the first cooling process involves cooling the quartz glass raw material to 1000 to 1500°C at a rate of 5 to 10°C / min, and the second cooling process involves cooling the quartz glass raw material to 600 to 800°C at a rate of 10 to 20°C / min.

[0007] In one possible implementation, the third heating process involves heating the first quartz glass component to 1000 to 1500°C at a rate of 10 to 20°C / min, the fourth heating process involves heating the first quartz glass component to 1900 to 2000°C at a rate of 5 to 10°C / min, and the second heat preservation process involves keeping the first quartz glass component at 1900 to 2000°C for 4 to 8 hours.

[0008] In one possible implementation, the third cooling process involves cooling the first quartz glass component to 1000 to 1500°C at a rate of 5 to 10°C / min, and the fourth cooling process involves cooling the first quartz glass component to 600 to 800°C at a rate of 10 to 20°C / min.

[0009] In one possible implementation, the pressure of the first pressure environment is 0.2 to 0.5 MPa, and the pressure of the second pressure environment is 0.2 to 0.5 MPa.

[0010] In one possible implementation, the first liquid washing process involves repeatedly washing the quartz glass raw material with oxalic acid and pure water; the second liquid washing process involves repeatedly washing the first quartz glass component with oxalic acid and pure water.

[0011] In one possible implementation, the quartz glass raw material has stripes in at least one light transmission direction, and along the light transmission direction, the end faces of opposite ends of the quartz glass raw material are set as light transmission surfaces. When the quartz glass raw material is placed in the forming tank, the bottom wall of the forming tank supports the light-transmitting surface.

[0012] In one possible implementation, the optical uniformity of the first quartz glass element is >10ppm, and the optical uniformity of the second quartz glass element is <2ppm.

[0013] In one possible implementation, the forming groove is square in shape.

[0014] The process for eliminating striations in quartz glass disclosed in this application employs a two-stage heating, holding, and cooling process during both the first sinking treatment of the quartz glass raw material and the second sinking treatment of the first quartz glass component. This two-stage heating and cooling process improves the optical uniformity of the quartz glass while ensuring efficient sinking, thus preventing striations from appearing on the quartz glass. Furthermore, by repeatedly sinking the quartz glass from different directions, the non-uniformities caused by differences in purity, temperature gradients, and cooling rates within the quartz glass can be completely homogenized, eliminating internal striations. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart of one embodiment of the process for eliminating striations in quartz glass according to this application.

[0016] Figure 2 This is a schematic diagram of the flipping of the first quartz glass piece in one embodiment of the process method for eliminating striations in quartz glass according to this application.

[0017] Explanation of key component symbols: 100, process for eliminating striations in quartz glass; 1, light-transmitting surface; 2, off-axis surface.

[0018] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0019] The following description will refer to the accompanying drawings to provide a more complete picture of the present application. The drawings illustrate exemplary embodiments of the present application. However, the present application may be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. The same reference numerals denote the same or similar components.

[0020] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit the application. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Furthermore, when used herein, “comprising” and / or “including” and / or “having,” integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, regions, integers, steps, operations, components, and / or groups thereof.

[0021] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Furthermore, unless expressly defined herein, terms such as those defined in a general dictionary should be interpreted as having the same meaning as they have in the relevant art and in the content of this application, and will not be interpreted as having an idealized or overly formal meaning.

[0022] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 and Figure 2 As shown, this embodiment provides a process method 100 for eliminating striations in quartz glass, including the following steps: S1. Provide quartz glass raw materials and a sinking mold, the sinking mold having a defined central axis, and the sinking mold having a forming groove extending along the direction of the central axis. S2. Perform a first liquid washing treatment on the quartz glass raw material; S3. The quartz glass raw material that has completed the first liquid washing treatment is placed in the forming tank, and the quartz glass raw material is subjected to the first tank sinking treatment under the first pressure environment. The first tank sinking treatment includes the first heating treatment, the second heating treatment, the first heat preservation treatment, the first cooling treatment, and the second cooling treatment in sequence to obtain the first quartz glass part. S4. The side of the first quartz glass piece that has just been formed in the forming tank is set as the off-axis surface 2. The first quartz glass piece is subjected to cold working treatment and second liquid washing treatment in sequence. S5. Place the first quartz glass piece that has completed the second liquid washing treatment into the forming tank, and make the bottom wall of the forming tank support the off-axis surface 2. Under the second pressure environment, perform the second tank sinking treatment on the first quartz glass piece. The second tank sinking treatment includes the third heating treatment, the fourth heating treatment, the second heat preservation treatment, the third cooling treatment, and the fourth cooling treatment performed in sequence. S6. Repeat the last two steps above until there are no obvious streaks on the first quartz glass piece, and obtain the second quartz glass piece.

[0024] Thus, the process 100 for eliminating striations in quartz glass according to this application employs a two-stage heating, holding, and cooling process during both the first sinking treatment of the quartz glass raw material and the second sinking treatment of the first quartz glass piece. This two-stage heating and cooling process improves the optical uniformity of the quartz glass while ensuring sinking efficiency, preventing striations from appearing on the quartz glass. Furthermore, by repeatedly sinking the quartz glass from different directions, the non-uniformity caused by differences in purity, temperature gradients, and cooling rates within the quartz glass can be completely homogenized, eliminating internal striations.

[0025] In this embodiment, for step S1, the quartz glass raw material is a quartz mother ingot, and the quartz glass raw material is sampled and tested. The quartz glass raw material has stripes in at least one light-transmitting direction, and along the light-transmitting direction, the end faces of the opposite ends of the quartz glass raw material are designated as light-transmitting surfaces 1. The sinking mold can be a graphite crucible. Along the direction of the central axis of the sinking mold, the forming groove extends inward from the end face of one end of the sinking mold. The volume of the forming groove is larger than the volume of the quartz glass raw material, so that the quartz glass raw material can be placed centrally in the forming groove.

[0026] The molding tank is square in shape so that the first quartz glass piece formed by melting and solidifying the quartz glass raw material in the molding tank is square in shape.

[0027] It is understood that in other embodiments, the shape of the forming groove can also be designed according to the required shape of the first quartz glass piece, and is not limited to the above-mentioned square shape.

[0028] In this embodiment, for step S2, the first liquid washing treatment involves repeatedly washing the quartz glass raw material with oxalic acid and pure water. Specifically, oxalic acid is dissolved in pure water to form an oxalic acid solution with a concentration of 1% to 3%. The quartz glass raw material is then immersed in the oxalic acid solution to remove impurities from its surface, such as metal impurity ions, dust, and some organic matter, thereby reducing optical defects such as streaks caused by the presence of impurities. After being acid-washed with the oxalic acid solution, the quartz glass raw material is then washed with pure water (either dynamic rinsing or static water exchange rinsing) to remove any residual oxalic acid solution from its surface.

[0029] It is worth noting that when immersing quartz glass raw materials in oxalic acid solution, the oxalic acid solution can be poured out after immersion, and new oxalic acid solution can be added to immerse the quartz glass raw materials again. This process can be repeated multiple times to ensure the immersion effect. When rinsing with pure water, pure water can also be used to repeatedly rinse all surfaces of the quartz glass raw materials to improve the cleaning effect.

[0030] In this embodiment, for step S3, when the quartz glass raw material that has completed the first liquid washing treatment is placed in the forming tank, one of the light-transmitting surfaces 1 of the quartz glass raw material is placed on the bottom wall of the forming tank.

[0031] After placing the quartz glass raw material into the sintering mold, the sintering mold is placed into the sintering furnace, and inert gas is injected into the furnace to pressurize it until the pressure of the initial pressure environment inside the furnace reaches 0.2 to 0.5 MPa. The inert gas can be nitrogen or helium, etc.

[0032] In this embodiment, the pressure of the first pressure environment can be 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, etc., but is not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the protection scope of this application.

[0033] The first heating treatment involves heating the quartz glass raw material to 1000 to 1500°C at a rate of 10 to 20°C / min; the second heating treatment involves heating the quartz glass raw material to 1900 to 2000°C at a rate of 5 to 10°C / min; and the first heat preservation treatment involves holding the quartz glass raw material at 1900 to 2000°C for 4 to 8 hours.

[0034] In this embodiment, the heating rate of the first heating process can be 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min, 20℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0035] In this embodiment, after the first heating process is completed, the temperature inside the sink furnace can specifically be 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, 1210℃, 1220℃, 1230℃, 1240℃, or 1250℃. Temperatures of 1260℃, 1270℃, 1280℃, 1290℃, 1300℃, 1310℃, 1320℃, 1330℃, 1340℃, 1350℃, 1360℃, 1370℃, 1380℃, 1390℃, 1400℃, 1410℃, 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, 1480℃, 1490℃, and 1500℃ are included, but are not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the scope of protection of this application.

[0036] In this embodiment, the heating rate of the first heating process can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0037] In this embodiment, after the second heating process is completed in the sink furnace, the temperature inside the sink furnace can be 1900℃, 1910℃, 1920℃, 1930℃, 1940℃, 1950℃, 1960℃, 1970℃, 1980℃, 1990℃, 2000℃, etc., but is not limited to the values ​​listed above. Other values ​​not listed within this range are also within the protection scope of this application.

[0038] In this embodiment, the heat preservation time of the first heat preservation treatment is 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, 5.0h, 5.1h, 5.2h, 5.3h, 5.4h, 5.5h, 5.6h, 5.7h, 5.8h, 5.9h, 6.0h, 6.1h, 6.2h, 6.3h, 6.4h, 6.5h, 6.6h, 6.7h, 6.8h, 6.9h, 7.0h, 7.1h, 7.2h, 7.3h, 7.4h, 7.5h, 7.6h, 7.7h, 7.8h, 7.9h, 8.0h, etc., but is not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the protection scope of this application.

[0039] Thus, the heating rate of the first heating treatment is greater than that of the second heating treatment, causing the furnace temperature to rise more rapidly, which improves production efficiency. The first heating treatment, occurring at a low temperature, has minimal impact on the material and can be heated at a faster rate. The second heating treatment, with its slower heating rate, reduces the overall temperature gradient of the material, allowing it to spread more evenly and simultaneously.

[0040] The first cooling process involves cooling the quartz glass raw material to 1000 to 1500°C at a rate of 5 to 10°C / min. The second cooling process involves cooling the quartz glass raw material to 600 to 800°C at a rate of 10 to 20°C / min, and then allowing it to cool naturally to room temperature before proceeding to the next step.

[0041] In this embodiment, the cooling rate of the first cooling process can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0042] In this embodiment, after the first cooling process is completed, the temperature inside the sink furnace can specifically be 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, 1210℃, 1220℃, 1230℃, 1240℃, or 1250℃. Temperatures of 1260℃, 1270℃, 1280℃, 1290℃, 1300℃, 1310℃, 1320℃, 1330℃, 1340℃, 1350℃, 1360℃, 1370℃, 1380℃, 1390℃, 1400℃, 1410℃, 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, 1480℃, 1490℃, and 1500℃ are included, but are not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the scope of protection of this application.

[0043] In this embodiment, the cooling rate of the second cooling process can be 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min, 20℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0044] In this embodiment, after the second cooling process is completed in the sink furnace, the temperature inside the sink furnace can be 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, etc., but is not limited to the values ​​listed above. Other values ​​not listed within this range are also within the protection scope of this application.

[0045] Thus, the cooling rate of the first cooling process is lower than that of the second cooling process, allowing the quartz glass raw material to cool slowly in the high-temperature zone. This provides sufficient thermodynamic driving force and time for structural rearrangement, ensuring better optical performance of the first quartz glass component after molding and avoiding the appearance of structural optical streaks. After the first cooling process is completed in the sink furnace, the quartz glass raw material has largely become a solid structure. At this point, production efficiency can be increased by increasing the cooling rate without causing optical streaks to appear, and prolonged stay in temperature ranges where crystallization may occur (such as in the presence of certain impurities) should be avoided.

[0046] In this embodiment, for step S4, when the quartz glass raw material is melted and solidified again in the forming tank to form the first quartz glass component, the bottom end face of the first quartz glass component is the light-transmitting surface 1, and the light-transmitting surface 1 is placed on the bottom wall of the forming tank. Furthermore, the shape of the formed first quartz glass component is the same as the shape of the forming tank, and the central axis of the first quartz glass component coincides with the central axis of the forming tank. All sides of the first quartz glass component in this state surrounding the central axis are designated as off-axis surfaces 2.

[0047] The first quartz glass component, after solidification, is removed from the settling furnace. Its surface is then subjected to cold working to remove any traces left by the settling process. This cold working involves milling, cutting, and fine carving, among other methods, the specific techniques of which are not limited in this application. The removal amount is 1 to 2 mm, primarily removing uneven areas and graphite adhering to the quartz. After the cold working, the first quartz glass component undergoes a second liquid washing process, which involves repeatedly cleaning it with oxalic acid and pure water.

[0048] It is worth noting that the second liquid washing treatment is the same in method and principle as the first liquid washing treatment described above, and will not be repeated here.

[0049] In this embodiment, for step S5, the first quartz glass piece that has undergone the second liquid washing treatment is placed in a forming tank, and the bottom wall of the forming tank supports an off-axis surface 2 of the first quartz glass piece. This off-axis surface 2 is defined by the state of the first quartz glass piece during the previous solidification process in the forming tank. Subsequently, the first quartz glass piece is placed in a sinking mold, and then the sinking mold is placed in a sinking furnace. Inert gas is injected into the sinking furnace to perform pressurization treatment until the pressure of the second pressure environment inside the sinking furnace is 0.2 to 0.5 MPa. The inert gas can be nitrogen or helium, etc.

[0050] In this embodiment, the pressure of the second pressure environment can be 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, etc., but is not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the protection scope of this application.

[0051] The third heating process involves heating the first quartz glass component to 1000 to 1500°C at a rate of 10 to 20°C / min; the fourth heating process involves heating the first quartz glass component to 1900 to 2000°C at a rate of 5 to 10°C / min; and the second heat preservation process involves keeping the first quartz glass component at 1900 to 2000°C for 4 to 8 hours.

[0052] In this embodiment, the heating rate of the third heating process can be 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min, 20℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0053] In this embodiment, after the third heating process is completed, the temperature inside the sink furnace can specifically be 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, 1210℃, 1220℃, 1230℃, 1240℃, or 1250℃. Temperatures of 1260℃, 1270℃, 1280℃, 1290℃, 1300℃, 1310℃, 1320℃, 1330℃, 1340℃, 1350℃, 1360℃, 1370℃, 1380℃, 1390℃, 1400℃, 1410℃, 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, 1480℃, 1490℃, and 1500℃ are included, but are not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the scope of protection of this application.

[0054] In this embodiment, the heating rate of the fourth heating process can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0055] In this embodiment, after the fourth heating process is completed in the sink furnace, the temperature inside the sink furnace can be 1900℃, 1910℃, 1920℃, 1930℃, 1940℃, 1950℃, 1960℃, 1970℃, 1980℃, 1990℃, 2000℃, etc., but is not limited to the values ​​listed above. Other values ​​not listed within this range are also within the protection scope of this application.

[0056] In this embodiment, the heat preservation time of the second heat preservation treatment is 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, 5.0h, 5.1h, 5.2h, 5.3h, 5.4h, 5.5h, 5.6h, 5.7h, 5.8h, 5.9h, 6.0h, 6.1h, 6.2h, 6.3h, 6.4h, 6.5h, 6.6h, 6.7h, 6.8h, 6.9h, 7.0h, 7.1h, 7.2h, 7.3h, 7.4h, 7.5h, 7.6h, 7.7h, 7.8h, 7.9h, 8.0h, etc., but is not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the protection scope of this application.

[0057] The third cooling process involves cooling the first quartz glass component to 1000 to 1500°C at a rate of 5 to 10°C / min, and the fourth cooling process involves cooling the first quartz glass component to 600 to 800°C at a rate of 10 to 20°C / min.

[0058] In this embodiment, the cooling rate of the third cooling process can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0059] In this embodiment, after the third cooling process is completed, the temperature inside the sink furnace can specifically be 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, 1200℃, 1210℃, 1220℃, 1230℃, 1240℃, or 1250℃. Temperatures of 1260℃, 1270℃, 1280℃, 1290℃, 1300℃, 1310℃, 1320℃, 1330℃, 1340℃, 1350℃, 1360℃, 1370℃, 1380℃, 1390℃, 1400℃, 1410℃, 1420℃, 1430℃, 1440℃, 1450℃, 1460℃, 1470℃, 1480℃, 1490℃, and 1500℃ are included, but are not limited to the values ​​listed above. Other unlisted values ​​within this range are also within the scope of protection of this application.

[0060] In this embodiment, the cooling rate of the fourth cooling process can be 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min, 20℃ / min, etc., but is not limited to the values ​​listed above. Other values ​​not listed in this range are also within the protection scope of this application.

[0061] In this embodiment, after the fourth cooling process is completed, the temperature inside the sink furnace can be 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, etc., but is not limited to the values ​​listed above. Other values ​​not listed within this range are also within the protection scope of this application.

[0062] It is worth noting that the principle of the second sinking treatment is the same as that of the first sinking treatment, and will not be repeated here.

[0063] In this embodiment, for step S6, after obtaining the newly melted first quartz glass piece after completing step S5, steps S4 and S5 are repeated sequentially until there are no obvious stripes on the first quartz glass piece, and a second quartz glass piece is obtained.

[0064] It is worth noting that when repeating steps S4 and S5, repeat at least four times first, then check whether there are stripes or distortions on the first quartz glass piece, and determine how many more times it needs to be repeated based on the detection results (e.g., the depth of the stripes). After the number of repetitions, perform another detection. If the stripes still exist, continue to repeat until no obvious stripes or distortions are detected on the first quartz glass piece, thus obtaining the second quartz glass piece.

[0065] In addition, the process is repeated four times in one cycle. During each cycle, the off-axis surface 2 of the first quartz glass piece in contact with the bottom wall of the forming tank is different. The first quartz glass piece is continuously flipped during the tank sinking process to further avoid the appearance of stripes.

[0066] In this embodiment, a second quartz glass component is obtained when no obvious stripes or distortions are detected on the first quartz glass component. The optical uniformity of the original first quartz glass component is generally >10ppm, while the uniformity of the original second quartz glass component obtained after processing is <2ppm, and can even reach <1ppm.

[0067] Example 1 Select a columnar quartz ingot with a specification of Φ380×430mm. Use a square graphite crucible with dimensions of 400×400×600mm. Soak and clean the quartz ingot with a 2% oxalic acid solution. Then rinse the surface of the quartz ingot with pure water. Repeat the soaking, cleaning and rinsing three times. Place the rinsed quartz ingot in a forming tank and place the graphite crucible in a sink furnace. Inject nitrogen into the sink furnace until the first pressure environment inside the sink furnace is 0.3MPa.

[0068] Subsequently, the temperature was increased to 1300℃ at a rate of 15℃ / min, then increased to 1900℃ at a rate of 8℃ / min, maintained for 5 hours, then decreased to 1300℃ at a rate of 8℃ / min, and then decreased to 700℃ at a rate of 15℃ / min.

[0069] The first quartz glass component is cold-worked, then soaked and cleaned with a 2% oxalic acid solution. Subsequently, the surface of the first quartz glass component is rinsed with pure water, and the soaking, cleaning and rinsing are repeated three times. The rinsed first quartz glass component is placed in a forming tank, ensuring that the off-axis surface 2 is in contact with the bottom wall of the forming tank. The graphite crucible is placed in the tank furnace, and nitrogen gas is injected into the tank furnace until the first pressure environment inside the tank furnace is 0.3 MPa.

[0070] Subsequently, the temperature was increased to 1300℃ at a rate of 15℃ / min, then increased to 1900℃ at a rate of 8℃ / min, maintained for 5 hours, then decreased to 1300℃ at a rate of 8℃ / min, and then decreased to 700℃ at a rate of 15℃ / min.

[0071] The first quartz glass piece was subjected to a six-sided polishing test. The first quartz glass piece exhibited obvious fringes. Steps S4 and S5 were repeated six times using the parameters specified in Example 1. Under the fringe analyzer, the fringes or distortions were observed to be significantly reduced in any three directions. Steps S4 and S5 were repeated five more times, resulting in a total of 11 troughing treatments. The first quartz glass piece was then subjected to a six-sided polishing test. No obvious fringes or distortions were observed under the fringe analyzer in any three directions, thus obtaining the second quartz glass piece. The optical properties of the second quartz glass piece were: no breaks or twists in the transmitted wavefront interference fringes; and a uniformity test result of 0.6 ppm.

[0072] Example 2 The only difference between this and Example 1 is that the heating rate of both the first and second sump treatments is adjusted from 15°C / min to 20°C / min, and the cooling rate of both the first and second sump treatments is adjusted from 15°C / min to 20°C / min.

[0073] The second quartz glass component was obtained after a total of 10 sinking processes. The optical properties of the second quartz glass component were that the transmitted wavefront interference fringes were free of breaks and twists, and the uniformity test result was 1.0 ppm.

[0074] Example 3 The only difference between this and Example 1 is that the heating temperature of both the first and second sedimentation treatments is adjusted from 1300°C to 1500°C, and the cooling temperature of both the first and second sedimentation treatments is adjusted from 1300°C to 1000°C.

[0075] The second quartz glass component was obtained after a total of 7 sinking processes. The optical properties of the second quartz glass component were that the transmitted wavefront interference fringes were free of breaks and twists, and the uniformity test result was 1.7 ppm.

[0076] Example 4 The only difference between this and Example 1 is that the holding time for both the first and second sink treatments has been adjusted from 5 hours to 7 hours.

[0077] The second quartz glass component was obtained after a total of 6 sinking processes. The optical properties of the second quartz glass component were that the transmitted wavefront interference fringes were free of breaks and twists, and the uniformity test result was 1.1 ppm.

[0078] Comparative Example 1 The only difference between it and Example 1 is that both the first and second immersion treatments are directly cooled to 700°C at a cooling rate of 8°C / min, that is, the two-stage cooling treatment is not used.

[0079] The second quartz glass component was obtained after a total of 7 sinking processes. The optical properties of the second quartz glass component were that the interference fringes on the transmitted wavefront had breaks and twists, and the uniformity test result was 11.6 ppm.

[0080] Comparative Example 2 The only difference between it and Example 1 is that the second sump treatment directly cools down to 700°C at a cooling rate of 8°C / min, that is, it does not use a two-stage cooling treatment.

[0081] The second quartz glass component was obtained after a total of 9 sinking processes. The optical properties of the second quartz glass component were that the transmitted wavefront interference fringes had breaks and twists, and the uniformity test result was 7.3 ppm.

[0082] Comparative Example 3 The only difference between it and Example 1 is that the first and second immersion treatments are both heated directly to 1900°C at a heating rate of 15°C / min, that is, the two-stage heating treatment is not used.

[0083] The second quartz glass component was obtained after a total of 9 sinking processes. The optical properties of the second quartz glass component showed that the transmitted wavefront interference fringes had breaks and twists, and the uniformity test result was 7.1 ppm.

[0084] Comparative Example 4 The only difference between it and Example 1 is that the second tank sedimentation treatment directly heats up to 1900°C at a heating rate of 15°C / min, that is, it does not use a two-stage heating treatment.

[0085] The second quartz glass component was obtained after a total of 8 sinking processes. The optical properties of the second quartz glass component were that the interference fringes on the transmitted wavefront had breaks and twists, and the uniformity test result was 8.6 ppm.

[0086] Comparative Example 5 The only difference between it and Embodiment 1 is that the surface of the first quartz glass piece in contact with the bottom wall of the forming tank remains unchanged in the first sinking process and each repeated second sinking process, that is, the first quartz glass piece is never flipped.

[0087] The second quartz glass component was obtained after 15 sinking processes. The optical properties of the second quartz glass component were that the transmitted wavefront interference fringes had obvious breaks and twists, and the uniformity test result was 11.3 ppm.

[0088] Comparative Example 6 The only difference between this and Example 1 is that no cold processing was performed, and the cooling temperature of the first and second sink treatments was adjusted from 700°C to 30°C.

[0089] The second quartz glass component was obtained after 12 trough treatments. The optical properties of the second quartz glass component were that the transmitted wavefront interference fringes were unbroken and twisted. The material contained bubbles and black graphite impurities, and the uniformity test result was 1.6 ppm.

[0090] Comparative Example 7 The only difference between this and Example 1 is that the pressure environment of both the first and second sedimentation treatments is adjusted from 0.3 MPa to 0.1 MPa.

[0091] The second quartz glass component was obtained after nine troughing processes. The optical properties of the second quartz glass component showed no breaks or twists in the transmitted wavefront interference fringes, and air bubbles were present inside the material. The uniformity test result was 1.4 ppm.

[0092] The specific embodiments of this application have been described above with reference to the accompanying drawings. However, those skilled in the art will understand that various changes and substitutions can be made to the specific embodiments of this application without departing from the scope of this application. All such changes and substitutions fall within the scope defined by this application.

Claims

1. A process for eliminating striations in quartz glass, characterized in that, Includes the following steps: Quartz glass raw materials and a sinking mold are provided. The sinking mold has a defined central axis and a forming groove extending along the direction of the central axis. The quartz glass raw material is subjected to a first liquid washing treatment; The quartz glass raw material that has completed the first liquid washing treatment is placed in the forming tank, and the quartz glass raw material is subjected to a first tank sinking treatment under a first pressure environment. The first tank sinking treatment includes a first heating treatment, a second heating treatment, a first heat preservation treatment, a first cooling treatment, and a second cooling treatment performed in sequence to obtain a first quartz glass part. The side of the first quartz glass piece that has just been formed in the forming groove is set as the off-axis surface, and the first quartz glass piece is subjected to cold working treatment and second liquid washing treatment in sequence. The first quartz glass piece that has completed the second liquid washing treatment is placed in the forming tank, and the bottom wall of the forming tank supports the off-axis surface. The first quartz glass piece is subjected to a second tank sinking treatment under a second pressure environment. The second tank sinking treatment includes a third heating treatment, a fourth heating treatment, a second heat preservation treatment, a third cooling treatment, and a fourth cooling treatment performed in sequence. Repeat the last two steps above until there are no obvious streaks on the first quartz glass piece, and obtain the second quartz glass piece.

2. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The first heating treatment involves heating the quartz glass raw material to 1000 to 1500°C at a rate of 10 to 20°C / min; the second heating treatment involves heating the quartz glass raw material to 1900 to 2000°C at a rate of 5 to 10°C / min; and the first heat preservation treatment involves keeping the quartz glass raw material at 1900 to 2000°C for 4 to 8 hours.

3. The process for eliminating striations in quartz glass as described in claim 2, characterized in that, The first cooling process involves cooling the quartz glass raw material to 1000 to 1500°C at a rate of 5 to 10°C / min, and the second cooling process involves cooling the quartz glass raw material to 600 to 800°C at a rate of 10 to 20°C / min.

4. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The third heating process involves heating the first quartz glass component to 1000 to 1500°C at a rate of 10 to 20°C / min; the fourth heating process involves heating the first quartz glass component to 1900 to 2000°C at a rate of 5 to 10°C / min; and the second heat preservation process involves keeping the first quartz glass component at 1900 to 2000°C for 4 to 8 hours.

5. The process for eliminating striations in quartz glass as described in claim 4, characterized in that, The third cooling process involves cooling the first quartz glass component to 1000 to 1500°C at a rate of 5 to 10°C / min, and the fourth cooling process involves cooling the first quartz glass component to 600 to 800°C at a rate of 10 to 20°C / min.

6. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The pressure of the first pressure environment is 0.2 to 0.5 MPa, and the pressure of the second pressure environment is 0.2 to 0.5 MPa.

7. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The first liquid washing treatment involves repeatedly washing the quartz glass raw material with oxalic acid and pure water multiple times; the second liquid washing treatment involves repeatedly washing the first quartz glass component with oxalic acid and pure water multiple times.

8. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The quartz glass raw material has stripes in at least one light transmission direction, and along the light transmission direction, the end faces of the opposite ends of the quartz glass raw material are set as light transmission surfaces. When the quartz glass raw material is placed in the forming tank, the bottom wall of the forming tank supports the light-transmitting surface.

9. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The optical uniformity of the first quartz glass component is >10ppm, and the optical uniformity of the second quartz glass component is <2ppm.

10. The process for eliminating striations in quartz glass as described in claim 1, characterized in that, The molding groove is square in shape.

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