Production process for high-generation display glass

Abstract

This invention discloses a production process for advanced display glass, in which the heating temperatures of various parts of a staged heating furnace are differentiated to achieve a controllable distribution of the thermodynamic field within the furnace. By combining the staged heating furnace with a hierarchical degassing and refining device, a synergistic effect between the two process steps is achieved, ensuring a relatively low residual microbubble rate and low energy consumption, improving the flow rate and volume of the glass melt, and increasing production yield. An innovative tin tank device is adopted that autonomously and controllably achieves differentiated discharge of tin vapor and tin tank exhaust gas from different areas, enabling precise control of the tin tank's air intake and exhaust and precise control of the temperature field. This invention innovatively combines multiple steps in the display glass substrate production process, resulting in a display glass substrate production process that fully utilizes resources, combines and complements advantages, and organically integrates the production line.

Description

[Technical Field]

[0001] The present invention relates to the field of glass production technology, and in particular to a production apparatus and production process suitable for producing display glass with low devitrification tendency and a low defect rate, a production method for producing optical elements from glass molded bodies obtained using the apparatus and process, and the produced optical elements. [Background technology]

[0002] Display glass substrates are a key strategic material for the information display industry and represent the highest standard in glass manufacturing. Producing high-quality, high-end, next-generation display glass substrates through smart, green, low-carbon, large-scale manufacturing processes is the goal pursued by scientific and technological research and development in this field.

[0003] Display devices, including liquid crystal displays, require extremely high quality on the surface and inside of glass substrates, and microbubbles are a very important control index in the glass substrate manufacturing process. Since a large number of bubbles are generated during the glass melting process, in order to obtain good, high-end, high-quality bubble-free glass melt, it is necessary to remove the bubbles from the glass melt to achieve an acceptable bubble defect range and state of the glass substrate.

[0004] Currently, there is a significant trend toward larger size and higher generation glass substrates, and many manufacturers are increasing the withdrawal rate to increase production capacity. However, as glass production capacity increases, the flow rate of the glass melt within the passage increases, shortening the residence time of bubbles within the refining tube segments. This significantly reduces the probability of bubbles coagulating, growing, and floating up, making it impossible to achieve timely and thorough refining and degassing, resulting in the formation of residual microbubbles within the glass plate.

[0005] Many glass substrates for high-end displays use alkali-free glass, which has a high melting temperature and high viscosity. Conventionally, the temperature of the molten glass is raised to promote the aggregation, growth, floating, and expulsion of bubbles in the molten glass.

[0006] However, increasing the melting capacity and temperature of glass melts results in enormous energy consumption, accounting for a relatively large proportion of the energy consumed in the glass production process. Simply increasing the temperature of the glass melt to alter the bubble generation, aggregation, growth, floating, and discharge processes results in a production method that is too extensive and the control method too monotonous. To achieve the goals of peaking CO2 emissions and achieving carbon neutrality, and to ensure the safety of China's information displays, how to develop a high-end display glass substrate production process that meets the production capacity requirements of large scale and high production capacity while also meeting the quality requirements of low bubble defect rates, high surface flatness, and high generation rates, while also meeting the environmental and economic requirements of green and low energy consumption, has become a hot research and development direction in this field. Summary of the Invention [Problem to be solved by the invention]

[0007] In response to the above problems, the present invention provides a smart, green, low-carbon, large-scale manufacturing apparatus and process for high-generation display glass substrates, suitable for producing display glass with low devitrification and low defect rates, as well as a manufacturing method for optical elements from glass bodies obtained using the apparatus and process, and the optical elements produced. The technical solution of the present invention effectively reduces or prevents residual microbubbles in the glass substrate, significantly improving the transmittance and uniformity of the glass substrate, suitable for producing high-generation, high-quality display glass substrates and ensuring the safety of information displays. It also effectively reduces energy consumption on the production line and achieves precise temperature control, promoting energy conservation, emission reduction, and consumption reduction in the glass industry and providing a technical option for China's CO2 emission peaking and carbon neutral goals. [Means for solving the problem]

[0008] The present invention provides an apparatus for producing display glass substrates, including a raw material mixing device, a stepwise heating and melting furnace, a stepwise degassing and refining device, a tin tank, an annealing furnace, a cutting and post-processing device, Here, the stepwise heating melting furnace comprises a control unit, a first melting section and a second melting section along the flow direction of the molten glass, a kiln weir is provided between the first melting section and the second melting section, a heating element is provided in the first melting section, and another heating element is provided in the second melting section, and the control unit is capable of controlling the heating state of each of the first melting section and the second melting section.

[0009] The hierarchical degassing and refining apparatus includes a hierarchical degassing and refining passage, which includes one or more degassing structures for hierarchically discharging bubbles from different depth regions of the glass melt, and the degassing structure includes a communicating pipe segment and a refining pipe segment, and the communicating pipe segment has an inner diameter smaller than that of the refining pipe segment.

[0010] The control unit of the stepwise heating melting furnace controls and adjusts the temperature of the first melting zone and the temperature of the second melting zone respectively to suit the degassing process of the hierarchical degassing and refining passage.

[0011] The present invention further provides a process for producing a glass substrate for a display using the above-mentioned apparatus for producing a glass substrate for a display, the process including a raw material mixing step, a stepwise heating step, a hierarchical degassing and fining step, a tin tank forming step, an annealing step, cutting and post-processing steps.

[0012] Here, the stepwise heating melting furnace in the stepwise heating step includes a control unit, a first melting section and a second melting section along the flow direction of the glass melt, a kiln weir is provided between the first melting section and the second melting section, a heating element is provided in the first melting section, and another heating element is provided in the second melting section, and the control unit is capable of controlling the heating of the first melting section and the second melting section, respectively.

[0013] The hierarchical degassing and refining device in the hierarchical degassing and refining step includes a hierarchical degassing and refining passage, which includes one or more degassing structures for hierarchically discharging bubbles from different depth regions of the glass melt, and the degassing structures include a communicating pipe segment and a refining pipe segment, and the communicating pipe segment has an inner diameter smaller than that of the refining pipe segment.

[0014] The control unit of the stepwise heating melting furnace controls and adjusts the temperature of the first melting zone and the temperature of the second melting zone respectively to suit the degassing process of the hierarchical degassing and refining passage.

[0015] Preferably, the present invention discloses the types and blending ratios of glass raw materials used in the production of display glass substrates, and the use of these raw materials can improve the quality of glass substrates, ensure smooth progress of the production process, and realize a green and environmentally friendly production process.

[0016] Preferably, the above-mentioned tin tank forming step adopts an advanced display glass protective gas implementation device, and includes a tin tank pool and a tin tank top cover, one or more sets of space dividing plates fixedly attached to the inside of the tin tank top cover, the space dividing plates dividing the inside of the tin tank top cover into one or more top cover inner grooves, and air supply pipes fixedly attached to the upper ends of all the top cover inner grooves, an exhaust gap is opened in the battlement wall above the tin tank pool, and one or more sets of exhaust pipes and an exhaust dividing plate are fixedly attached inside the exhaust gap to divide it into multiple independent grooves, and each of the above-mentioned independent grooves is provided with at least one exhaust pipe. This enables autonomous and controllable differentiated supply of protective gas to different areas and differentiated discharge of tin vapor and exhaust gas from different areas in the tin tank, ensuring that protective gas is supplied as needed and tin vapor and exhaust gas are discharged as needed, achieving precise control of air supply and exhaust, maximizing the consistency of the protective gas environment, reducing the residence time of tin vapor at any location in the tank, reducing the probability of defects forming on the glass sheet surface, and improving product quality.

[0017] Preferably, a transfer roll table integrally connected to the annealing furnace is provided upstream of the annealing furnace, and preferably, the high-temperature exhaust gas from the tin tank is purified and filtered through a heat-insulating pipeline before being supplied to the annealing furnace, and all of the high-temperature protective gas in the tin tank is supplied to the annealing furnace, thereby effectively utilizing the residual heat of the exhaust gas from the tin tank, recycling the waste heat, increasing the thermal energy utilization rate, saving energy, reducing the oxygen content in the annealing furnace, and extending the service life of the equipment. The annealing furnace is provided with one or more exhaust pipes, each with a thermocouple on one side and a lift-up shielding curtain on the other side, and further equipped with a control unit that can accurately control the exhaust of each exhaust pipe, the lift-up shielding curtain, and the heating of the heating device according to the temperature demands of different positions in the annealing furnace, thereby improving the three-dimensional temperature control precision of the annealing furnace.

[0018] The present invention further provides a method for producing an optical element using a glass molded article produced by the above-mentioned production process for a glass substrate for a display.

[0019] The present invention further provides an optical element manufactured using a glass molded body produced by the above-mentioned production process for a glass substrate for a display.

[0020] The beneficial effects of the present invention are as follows: The present invention has made technological innovations in multiple steps of the display glass substrate production process, discovered and utilized the advantages of each step, and conducted innovative research into combining steps, thereby fully utilizing resources, synergizing and complementing advantages, and forming a display glass substrate production process that organically unifies the production line.

[0021] Specifically, according to the present invention, the three-dimensional distribution patterns of bubbles of different sizes in a glass melt at different temperatures, at different positions in a melting furnace, and at different positions in a refining passage are calculated and observed, and an innovative combination of a staged heating melting furnace and a hierarchical degassing and refining device and production process is designed through an ingenious concept.

[0022] According to the multiple degassing structures of the hierarchical degassing and refining device, when a molten glass liquid containing a large number of bubbles of different diameters flows through this structure, the relatively low communicating pipe segments effectively separate the lower molten glass liquid containing a large number of relatively small bubbles from the upper molten glass liquid having a large number of relatively large bubbles, and the upper molten glass liquid having a large number of bubbles is blocked, causing the bubbles to coagulate, grow, float, and be discharged from the exhaust pipe at the top, thereby realizing the function of selecting the flow of the molten glass liquid.

[0023] Meanwhile, when molten glass containing a small number of bubbles flows through a variable-diameter pipe, the inclined pipe accelerates the aggregation, growth, and floating of the bubbles, and they are then discharged through the next exhaust pipe. As the molten glass continues to flow downstream, it experiences the process of aggregation, growth, floating, and discharge multiple times, thereby achieving sufficient discharge of the microbubbles in the molten glass and enabling the gradual discharge of bubbles from the molten glass, efficiently fining the molten glass and resolving the difficult problem of incomplete fining of large flow rates of molten glass.

[0024] After extensive research, the applicant discovered that by differentially controlling the heating temperatures of each part of a staged heating furnace, it is possible to achieve a controllable distribution of the thermodynamic field within the furnace, and by combining a staged heating furnace with a tiered defoaming and refining device, it is possible to achieve a synergistic effect between the two process steps. By utilizing the characteristics of the tiered defoaming and refining device, which contributes to the bubble aggregation, expansion, floating, and discharge processes, under the premise of more completely eliminating bubbles in the glass melt, it is possible to control the distribution of the thermodynamic field within the furnace, rationally distribute heat, supply heat as needed, and save resources. At the same time, by utilizing the characteristics of the staged heating furnace, which more precisely controls the distribution of the thermodynamic field of the melt in different dimensions, it is possible to promote the controllable generation of bubbles in the glass melt, changing the bubble distribution density of different laminar flows in the glass melt. By skillfully combining the structural design of the tiered defoaming and refining device, it is possible to achieve the purpose of improving the efficiency of bubble elimination in the glass, greatly reducing the residual microbubbles in the glass sheet, and improving the quality of the glass substrate. The combination of differentiated control of the staged heating melting furnace and the hierarchical defoaming and refining device ensures a relatively low residual microbubble rate and low energy consumption, which in turn improves the flow rate and volume of the glass melt, increasing production volume and enabling large-scale production.

[0025] According to the production process of the present invention, an innovative tin tank device is simultaneously adopted, which autonomously and controllably realizes differentiated supply of protective gas to different areas and differentiated discharge of tin vapor and tin tank exhaust gas from different areas, thereby achieving precise control of the tin tank's air supply and exhaust, and precise control of the temperature field, maximizing the controllability and consistency of the protective gas and environment, reducing the residence time of tin vapor at any location in the tank, and improving product quality and the level of smart production.

[0026] The present invention cleverly arranges and fully utilizes the waste heat resources in the production line, utilizing the high-temperature protective gas from the tin tank in the annealing kiln, and integrating the transfer roll table and the annealing kiln to maximize the utilization of the waste heat from the tin tank in the annealing kiln. To fully utilize the waste heat from the tin tank, one or more exhaust pipes and a rising / lowering shielding curtain are arranged at the top of the annealing kiln from the kiln entrance to the exit, and the control unit controls the exhaust and the raising / lowering of the shielding curtain, so that the raising / lowering of the shielding curtain, exhaust, and heating can be intelligently controlled according to the temperature demands of different positions in the annealing kiln. Therefore, under the premise of maximizing the utilization of the waste heat from the tin tank, the temperature in different areas in the annealing kiln can be precisely controlled, which further improves the annealing effect, improves energy utilization efficiency, extends the service life of the equipment, and further improves the level of intelligent and automated control.

[0027] According to the above-mentioned production process, the unified allocation and specifications of resources, the refined processes, and the precise control have realized the organic cooperation of each production process, and better achieved the advanced manufacturing goals of green, smart, large-scale, high-quality, and high-generation glass substrates. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic diagram of a production line. [Figure 2] FIG. 1 is a front view of a stepwise heating and melting furnace. [Figure 3] FIG. 1 is a left side view of a stepwise heating melting furnace. [Figure 4] FIG. 1 is a right side view of a stepwise heating melting furnace. [Figure 5] FIG. 1 is a plan view of a stepwise heating and melting furnace. [Figure 6] FIG. 1 is a cross-sectional view of a hierarchical degassing and fining device. [Figure 7] FIG. 1 is a structural schematic diagram of a hierarchical degassing and fining device. [Figure 8] FIG. 1 is a schematic diagram of the interconnection of a finer tube segment and a communicating tube segment. [Figure 9] FIG. 1 is a schematic diagram of the structure of a tin tank. [Figure 10] FIG. 1 is a partially enlarged view of a tin tank. [Figure 11] FIG. 1 is a plan view of the top cover of the tin tank. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the accompanying drawings in the embodiments of the present invention. It is clear that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments that a person skilled in the art can obtain without creative work fall within the scope of protection of the present invention.

[0030] As shown in FIG. 1, the equipment and process for producing display glass substrates includes a raw material mixing device 100, a step-by-step heating and melting furnace 200, a step-by-step degassing and fining device 300, a tin tank 400, an annealing furnace 500, a cutting machine 600, etc. The structure and process conditions of each device are described in detail as follows:

[0031] Raw materials: The glass raw material of the present invention is preferably an alkali-free glass raw material, and is, in weight percent, The raw materials include 59-75% SiO2, 12-20% Al2O3, 6-12% B2O3, 0.5-8% MgO, 2-10% CaO, 0.5-8% SrO, 0.1-3% ZrO2, 0.5-6% P2O5, and 0.06-1% SnO2. Here, SiO2 + Al2O3 is 71 to 85%, (MgO+CaO+SrO) / Al2O3 is 0.3 to 1, The total amount of alkaline earth metal oxides is 3 to 15%; B2O3 / (B2O3+ZrO2+P2O5) is 0.5 to 1.0, (ZrO2+P2O5) / (MgO+CaO+SrO) is 0.1 to 1.0.

[0032] Preferably, the glass composition has a β-OH value of less than 0.5%, a boron volatilization rate of less than 11%, and a thermal expansion coefficient of 39.5×10 in the range of 50 to 350°C. -7 / °C, Young's modulus higher than 80GPa, strain point higher than 700°C, melting temperature lower than 1662°C, and heat shrinkage lower than 10ppm.

[0033] The above raw materials do not contain toxic substances, are grown and environmentally friendly, and are suitable for mass production of glass substrates for advanced displays. By combining them with other steps in the production process of the present invention, it is possible to produce glass substrates for displays that have properties such as a high strain point, a high Young's modulus, high hardness, a high specific elastic modulus, an appropriate thermal expansion coefficient, and a low thermal shrinkage rate.

[0034] Step-by-step heating furnace: The stepwise heating melting furnace of the present application comprises a control unit, and a first melting section and a second melting section along the flow direction of the molten glass. A kiln weir is provided between the first melting section and the second melting section to divide the melting furnace into the first melting section and the second melting section. A heating element is provided in the first melting section, and another heating element is provided in the second melting section. The control unit is capable of controlling the heating of the first melting section and the second melting section, respectively.

[0035] Preferably, the aspect ratio of the melting furnace is in the range of 2:1 to 3.5:1, and the furnace weir is provided at a position 2 / 3 to 4 / 5 of the length of the pool.

[0036] The heating elements used in the first and second melting zones and the installation methods of each heating element may be the same or different, and the heating elements may be common heating elements such as burners and heating electrodes. Preferably, the melting furnace is equipped with a bubbling device installed in the first melting zone so as to be located upstream of the kiln weir. More preferably, the heating method for both the first and second melting zones uses a combination of heating electrodes and burners. More preferably, molybdenum electrodes may be selected as the heating electrodes. More preferably, the first melting zone, i.e., upstream of the kiln weir, is heated by combustion using a combination of bottom-inserted rod-type molybdenum electrodes and burners, and the second melting zone, i.e., downstream of the kiln weir, is heated by combustion using a combination of side-inserted plate-type molybdenum electrodes, side-inserted rod-type molybdenum electrodes, or a combination of side-inserted plate-type and rod-type molybdenum electrodes and burners. More preferably, the flames emitted from the burners are distributed horizontally, the burning gas is natural gas mixed with hydrogen gas at a volume content of 0 to 40%, and the burners are arranged symmetrically in two rows on the breastworks on both sides of the molten zone.

[0037] The control method of the first melting section and the second melting section by the control unit of the melting furnace of the present invention may be a temperature control method that combines temperature collection and control, such as combining general temperature collection and adjusting the heat output of the heating element.

[0038] Preferably, the temperature difference between the first melted portion and the second melted portion is 5°C to 40°C, more preferably 10°C to 30°C.

[0039] The temperature of the first molten zone may be 1650 to 1690°C, preferably 1650 to 1680°C, and more preferably 1660 to 1670°C.

[0040] The temperature of the second molten zone may be 1600 to 1650°C, preferably 1620 to 1640°C, and more preferably 1630 to 1640°C.

[0041] 2 to 5, the interior of a melting furnace 200 is divided into a first melting zone 201 and a second melting zone 202 that are sequentially connected along the flow direction of the molten glass, and a kiln weir is provided between the first melting zone and the second melting zone. Preferably, the melting furnace includes a bubbling device 206 provided in the first melting zone so as to be located upstream of the kiln weir. The melting furnace further includes a control unit that controls the temperatures of the first melting zone and the second melting zone.

[0042] The first melting zone, i.e., upstream of the kiln gate, is heated by combustion using a bottom-inserted rod-shaped molybdenum electrode 203 in combination with a burner. The second melting zone, i.e., downstream of the kiln gate, is heated by combustion using an electrode 205 in combination with a burner 206. The electrode 205 may be a side-inserted plate-type molybdenum electrode, a side-inserted rod-type molybdenum electrode, or a combination of a side-inserted plate-type and rod-type molybdenum electrode. This configuration enhances the melting capacity of the first melting zone, meets the requirement for precise temperature control due to the differentiation between the first and second melting zones, and ensures the harmony and unification of the two melting zones' strong melting capabilities and low energy consumption. To meet green, eco-friendly, and low-carbon requirements, the burner-based combustion heating method preferably employs oxygen-enriched combustion of natural gas mixed with 0-40% hydrogen by volume.

[0043] Hierarchical degassing and clarification equipment: 6 to 8, the hierarchical degassing and refining apparatus 300 of the present invention includes a heating pipe 302, a hierarchical degassing and refining passage, a cooling pipe 307, a stirring bucket 308, and a raw material supply pipe 309, which are connected in sequence as needed along the conveying direction of the glass melt. The heating pipe 302 and each of the other segments of the hierarchical degassing and refining passage are provided with an external heating device, which may be electric heating or other common heating method, and heat can be supplied to the glass melt via the external heating device of each segment.

[0044] Platinum passages are preferably used as the tiered degassing and refining passages. While other types of passages may be used, platinum flow paths are used in this embodiment. The tiered degassing and refining passages include one or more degassing structures for tieredly discharging bubbles from different depth regions of the glass melt. The degassing structures include a communicating pipe segment 303 and a refining pipe segment 305 connected in series, and preferably further include a modified pipe segment 304. The communicating pipe segment 303 has a smaller inner diameter than the refining pipe segment 305, and the modified pipe segment 304 connects the communicating pipe segment 303 and the refining pipe segment 305. By connecting the small-diameter communicating pipe segment 303 and the different-diameter pipe to the large-diameter refining pipe segment 305, the mechanical strength of the refining pipe is effectively increased, effectively supporting the relatively high-temperature pipe body, reducing the creep deformation of the entire tiered degassing refining passage at high temperatures, ensuring its thermal stability at high temperatures, avoiding the risk of collapse of the tiered degassing refining passage due to high-temperature deformation, and extending the service life of the tiered degassing refining passage.

[0045] During the transport of the molten glass, the height of glass melt level 301 inside refining tube segment 305 is defined as L0, the height of the upper surface of refining tube segment 305 as L1, and the height of the upper surface of connecting tube segment 303 as L2, with L1 > L0 > L2. By satisfying this relationship, when the molten glass flows through the degassing structure, connecting tube segment 303, which is lower than level L0, can effectively separate the molten glass containing a large number of bubbles. The upper molten glass containing a large number of bubbles is blocked, and the bubbles coagulate, grow, float, and are then discharged from exhaust pipe 306 at the top. Meanwhile, only the lower molten glass containing relatively fewer and smaller bubbles flows in, thereby realizing the function of selecting the flow of the molten glass.

[0046] By arranging the degassing structure in multiple layers, it is possible to separate different layers of glass melt and achieve hierarchical degassing, and with a degassing and fining segment of the same length, it is possible to achieve a higher fining efficiency than with a conventional platinum passage.

[0047] The inner diameters of the communicating pipe segments 303 in one or more degassing structures are all different, and the inner diameters of the communicating pipe segments 303 gradually decrease along the glass melt transport direction. Referring to Figure 8, lines a, b, and c are schematic diagrams of the butting of the finer pipe segments 305 and communicating pipe segments 303 of three degassing structures arranged along the glass melt transport direction, respectively, where H0 represents the pipe diameter of the finer pipe segment 305, H1 represents the pipe diameter of the communicating pipe segment 303 of the first degassing structure, and H2 and H3 represent the pipe diameters of the communicating pipe segments 303 of the second and third degassing structures, respectively, where H0>H1>H2>H3.

[0048] The hatched areas represent the partitions 314 between the different degassing structures. When bubbles of different sizes first pass through a, the bubbles in the upper layer are blocked by the hatched area, prolonging their retention, causing them to aggregate, grow, rise, and be discharged. After the glass melt containing small bubbles passes through H1, the small bubbles continue to aggregate and rise under the influence of the inclined upper surface tube with a varying diameter, and the bubbles in the middle layer gradually become bubbles in the upper layer. When passing through b, the bubbles in the upper layer are blocked by the hatched area, causing them to aggregate, grow, rise, and be discharged. The glass melt containing a small number of small bubbles in the lower layer again flows through the smaller diameter tube H2. Similarly, when passing through the next degassing structure c, the small number of small bubbles gradually grow larger and rise to the top of the glass melt. When passing through H3, they are trapped, aggregate, grow, and are discharged. When a glass melt containing a large number of bubbles with different diameters passes through a plurality of degassing structures, the bubbles are discharged in a hierarchical manner, thereby obtaining a clean glass melt flow.

[0049] One end of the communicating pipe segment 303 is fixedly connected to the special-shaped pipe segment 304, and the end opening shape of the special-shaped pipe segment 304 where it connects to the communicating pipe segment 303 matches the end opening shape of the communicating pipe segment 303. The end of the modified pipe segment 304 remote from the communicating pipe segment 303 is fixedly connected to the finer pipe segment 305, and the end opening shape of this end matches the end opening shape of the finer pipe segment 305. The horizontal heights of the bottom surfaces of the finer pipe segment 305, the communicating pipe segment 303, and the special-shaped pipe segment 304 are the same, and preferably, the top of the special-shaped pipe segment 304 is configured as a slope.

[0050] A partition plate 314 is fixedly connected to one end of the finer tube segment 305 remote from the profiled tube segment 304, and a through-hole is opened at the bottom of one side of the partition plate 314 for interconnection with another communicating tube segment. The other communicating tube segment refers to a communicating tube segment in another adjacent degassing structure. An exhaust pipe 306 is fixedly connected to the top of the finer tube segment 305, closer to the partition plate 314, and its tip is bent downward. One end of the cooling pipe 307 is fixedly connected to a stirring bucket 308, a stirring motor 310 is fixedly attached to the top of the stirring bucket 308, a stirring rod is fixedly connected to the output end of the stirring motor 310, and a raw material supply pipe 309 is fixedly connected to the bottom of one side of the stirring bucket 308.

[0051] The temperature of the inlet melt entering the hierarchical degassing and refining passage is preferably 1590°C to 1640°C, more preferably 1600°C to 1630°C, and even more preferably 1615°C to 1630°C, and the temperature of the outlet melt leaving the hierarchical degassing and refining passage is preferably 1570°C to 1590°C, more preferably 1575°C to 1585°C, and even more preferably 1580°C to 1585°C.

[0052] Tin Tank: Liquid crystal displays have very high requirements for the micro-waviness and surface roughness of glass substrates. In order to reduce the possibility of warping, waviness, and surface scratches, and to reduce the impact of tin vapor condensation, the tin tank of the present invention precisely controls the supply of protective gas and the exhaust of tin vapor in different areas, thereby ensuring the consistency and cleanliness of the environment inside the tin tank.

[0053] 9 to 11, the glass tin tank includes a tin tank pool 401 and a tin tank top cover 406, which are hermetically sealed together. A top heat insulating layer 404 is provided between the tin tank pool 401 and the tin tank top cover 406. One or more sets of space dividing plates 408 are fixedly attached to the inside of the tin tank top cover 406, which divide the inside of the tin tank top cover 406 into one or more top cover inner grooves 405. Air supply pipes 407 are attached to the upper ends of the top cover inner grooves 405, and protective gas supplied from the air supply pipes can enter the tin tank pool through the holes and gaps in the heat insulating layer. An exhaust gap 409 is opened in the battlement above the tin tank pool 401, and one or more sets of exhaust pipes 414 are fixedly attached inside the exhaust gap 409. An exhaust dividing plate 413 is attached inside the exhaust gap 409 to divide the exhaust gap into a plurality of independent grooves, and each of the independent grooves divided by the exhaust dividing plate is provided with at least one exhaust pipe 414. The intake and exhaust control device can individually control the flow rate of each intake pipe and exhaust pipe, and the control can be performed using a general data collection and flow control control method such as integrated operating state parameter collection, intake and exhaust adjustment, etc.

[0054] The glass melt floats on the tin liquid, and protective gas is supplied and discharged between the tin tank pool 401 and the tin tank top cover 406 via an air supply pipe 407 and an exhaust pipe 414, so that the protective gas flows through the tin tank top cover 406 and the tin tank pool 401.

[0055] The protective gas supplied through the air supply pipe 407 is a mixture of nitrogen gas and hydrogen gas, with the ratio of nitrogen gas to hydrogen gas being (94-100):(0-6). By controlling the air supply, the ratio of hydrogen gas in the nitrogen-hydrogen protective gas in the tin tank pool increases stepwise from the upstream end to the downstream end of the tin tank, and the tank pressure of the tin tank is controlled to a positive pressure 10-30 Pa higher than standard atmospheric pressure. The combination of one or more air supply pipes 407 and space divider plates 408 forms one or more independent protective gas supply structures above the tin tank top cover 406, allowing for high-density, area-specific operation of the tin tank top cover 406 of the tin tank pool 401, highly precise control of the amount of protective gas in each sub-area, and precise control of the temperature field inside the tin tank pool 401, further improving control over glass thickness, warpage, and waviness. By preventing the intrusion of oxygen or any oxidizing substances, oxidation of the tin liquid 411 is prevented, preventing the oxidized tin liquid from turning into tin oxide dust and damaging the glass substrate. Adjusting the air supply and exhaust according to changes in the glass melt temperature also allows for precise control over glass processing, improving glass processing quality. Precise control of air intake and exhaust minimizes the accumulation of tin vapor anywhere in the tank, prevents tin vapor condensation in gaps between the top insulation bricks and the parapet insulation bricks, and reduces the probability of defects forming on the glass plate surface.

[0056] Annealing: The annealing furnace of the present invention is an ultra-thin glass annealing furnace, and preferably, the transfer roll table between the tin tank and the annealing furnace is integrally connected to the annealing furnace, the top cover of the transfer roll table is integrally connected to the top cover of the annealing furnace, and the bottom case of the annealing furnace is integrally connected to the bottom case of the transfer roll table.

[0057] Preferably, the high-temperature exhaust gas from the tin tank is purified and filtered in a heat-insulating pipe before being supplied to the annealing furnace so that all of the high-temperature protective gas in the tin tank is introduced into the annealing furnace. Preferably, other inert protective gases must also be passed through the annealing furnace as needed, in addition to the high-temperature protective gas in the tin tank.

[0058] Preferably, one or more exhaust pipes are arranged at the top of the annealing furnace in the direction from the kiln entrance to the outlet, and a thermocouple is provided on one side of each exhaust pipe, and a liftable shielding curtain is provided on the other side of the exhaust pipe.A heating device and an annealing furnace control unit are provided inside the annealing furnace, and electrical signal connections are formed between the thermocouple, the liftable shielding curtain, the heating device, and the annealing furnace control unit.

[0059] The thermocouples send temperature data from different areas inside the annealing furnace to the annealing furnace control unit, which then controls the shielding curtain to rise and fall to the appropriate height based on these values. At the same time, it controls the exhaust volume of the exhaust pipe and the heating device inside the annealing furnace, thereby accurately controlling the temperatures in different areas inside the annealing furnace. At the same time, it effectively utilizes the thermal energy of the high-temperature protective gas inside the tin tank, reducing energy consumption and significantly lowering production costs.

[0060] This annealing furnace effectively utilizes the residual heat of the tin tank, reduces the amount of wind passing through the annealing furnace, improves the accuracy of the three-dimensional temperature control of the annealing furnace, reduces the oxygen content in the annealing furnace, and improves the service life of the equipment.

[0061] The present invention further relates to a method for producing an optical element by using a glass molded body produced by the above-mentioned production process for a glass substrate for a display.

[0062] The present invention further relates to an optical element manufactured using a glass molded body produced by the above-mentioned production process for a glass substrate for a display.

[0063] Example 1 A glass substrate raw material was prepared with a weight percentage of 62% SiO2, 9% B2O3, 17% Al2O3, 4% CaO, 2% MgO, 3.8% SrO, 1% ZrO2, 1% P2O5, and 0.2% SnO2, and this raw material was an alkali-free glass substrate raw material. The control unit controls the melting temperature of the first heating unit 201 of the stepwise heating melting furnace 200 to 1660°C and the melting temperature of the second heating unit 202 to 1640°C, and controls the pressure inside the furnace to a positive pressure 5±0.5 Pa higher than standard atmospheric pressure. After the glass raw material melt is melted, it flows into the tiered degassing and refining device 300. The tiered degassing and refining device 300 used in this embodiment is a platinum channel. The temperature of the melt entering the tiered degassing and refining device 300 is 1630°C, and the temperature of the melt leaving the tiered degassing and refining device 300 is 1580°C. After passing through the three-stage tiered degassing and refining structure, it enters the tin tank 400 for forming. The inlet temperature of the tin tank is 1300°C, and the outlet temperature of the tin tank is 800°C. The requirements for the tin tank protective gas are as follows: The ratio of nitrogen gas to hydrogen gas is (94-100):(0-6), and the hydrogen gas ratio increases stepwise from the upstream end to the downstream end of the tin tank. The tank pressure of the tin tank is controlled to a positive pressure 10-30 Pa higher than standard atmospheric pressure. The glass substrate then enters the annealing furnace 500, where the inlet temperature is 750°C and the outlet temperature is 50°C to ensure sufficient annealing of the glass plate. After annealing, post-processing steps such as cutting are performed.

[0064] In Examples 2 and 3 and Comparative Examples 1 and 2, the molding method was the same as that in Example 1, and the specific process parameters employed were as shown in Table 1 below.

[0065] Detection: The number of bubbles (pcs / kg), light transmittance, and total energy consumption (kJ / kg) of the melting furnace and the hierarchical degassing and refining device of the glass substrates obtained from the examples and comparative examples were measured and statistics were collected.

[0066] The test equipment used here is as follows: Bubble inspection equipment: The number and distribution of bubbles was detected using an ISRA plate glass defect detection equipment, and the number of bubbles per unit weight was calculated manually. Transmittance detection equipment: A UV-Visible-Near Infrared Spectrophotometer (model: Lambda 750 S) was used to test the transmittance of the glass plate in the visible light range. The final results are shown in the following table. Table 1 JPEG2025528294000002.jpg117170JPEG2025528294000003.jpg28170

[0067] From the above-mentioned performance and energy consumption measurements and statistics, it is clear that the technical solution of the present invention can achieve relatively good technical effects, the produced glass substrate has relatively high light transmittance, the number of bubbles is relatively small, and the process can reduce the specific energy consumption.

[0068] The applicant of the present invention conducted a large amount of experiments and in-depth theoretical research, analyzing multiple factors such as bubble generation density, bubble generation size, bubble rising rate, bubble absorption limit, and energy consumption limit in each melt laminar flow at different temperatures, and made a breakthrough by combining segment-by-segment temperature control of a glass melting furnace with a hierarchical degassing and fining process, which enables differentiated control of the temperatures at different positions in the melting furnace based on the change pattern of the temperature field at different flow positions of the glass melt and the optimal temperatures at different flow positions of the glass melt required for bubble discharge, thereby improving the precision and autonomy of temperature control. The glass melt heated through precise temperature control is passed through a hierarchical defoaming and fining device, and based on the distribution pattern of bubbles of different sizes in three dimensions within the hierarchical defoaming and fining passage and the layer distribution pattern of the melt containing bubbles of different sizes, one or more defoaming structures are used to classify and separate bubbles of different sizes as the glass layer liquid with bubbles of different diameters passes through the structure, or to classify and remove them by adopting a method combining separation and self-absorption, thereby effectively separating and eliminating bubbles, with significant beneficial effects.

[0069] This production process involves in-depth research and careful selection of the raw material mixing ratio, melting in the melting furnace, degassing in the fining channel, forming in the tin tank, annealing, and other steps, achieving organic collaboration between each production process step, realizing the organic integration of green, large-scale, smart, high-quality, and high-generation production, while also taking into consideration energy savings, consumption reduction, quality improvement, and social and economic benefits, and has good future potential for application.

[0070] The above description is merely preferred embodiments and examples of the present invention, and the present disclosure is not limited to the specific details of the above-mentioned embodiments and examples. Various simple modifications of the technical solutions of the present disclosure are possible within the scope of the technical concept of the present disclosure, and all such modifications fall within the scope of protection of the present disclosure. It should be noted that the specific technical features described in the above-mentioned specific embodiments and examples may be combined in any appropriate manner as long as they are not contradictory. To avoid unnecessary repetition, the present disclosure will omit a description of various possible combinations. Furthermore, any combination between various different embodiments and examples of the present disclosure is also possible, and should be considered as part of the disclosure as long as it does not contradict the concept of the present disclosure.

Claims

1. An apparatus for producing display glass substrates, comprising a raw material mixing device, a stepwise heating and melting furnace, a stepwise degassing and refining device, a tin tank, an annealing furnace, and a cutting and post-processing device, The stepwise heating melting furnace includes a control unit, a first melting zone and a second melting zone along a flow direction of molten glass, the first melting zone is provided with a heating element and the second melting zone is provided with another heating element, and the control unit is capable of controlling the heating states of the first melting zone and the second melting zone, respectively; a hierarchical degassing and refining apparatus including a hierarchical degassing and refining passage, the hierarchical degassing and refining passage including one or more degassing structures for hierarchically discharging bubbles in different depth regions of the glass melt, the degassing structure including a communicating pipe segment and a refining pipe segment, the communicating pipe segment having an inner diameter smaller than that of the refining pipe segment; The control unit of the stepwise heating melting furnace controls and adjusts the temperature of the first melting section and the temperature of the second melting section to suit the degassing process of the stepwise degassing and refining passage. An apparatus for producing glass substrates for displays, characterized in that:

2. A kiln gate is provided between the first melting section and the second melting section, the aspect ratio of the melting kiln is in the range of 2:1 to 3.5:1, and the kiln gate is provided at a position 2 / 3 to 4 / 5 of the pool length.

2. The apparatus for producing glass substrates for displays according to claim 1.

3. The melting furnace is equipped with a bubbling device installed in the first melting section so as to be located upstream of the kiln weir. The heating method for both the first melting section and the second melting section is a combination of heating electrodes and burners. Molybdenum electrodes can be selected as the heating electrodes. The flames emitted from the burners are distributed horizontally. The burning gas is natural gas mixed with 0-40% hydrogen gas by volume. The burners are divided into two rows and arranged symmetrically on the battlements on both sides of the melting section.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

4. The first fusion zone is heated by combustion using a bottom-inserted rod-type molybdenum electrode in combination with a burner, and the second fusion zone is heated by combustion using a side-inserted plate-type molybdenum electrode, a side-inserted rod-type molybdenum electrode, or a combination of a side-inserted plate-type and rod-type molybdenum electrode in combination with a burner.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

5. The tiered degassing and refining apparatus includes a heating pipe, a tiered degassing and refining passage, a cooling pipe, a stirring bucket, and a raw material supply pipe, which are connected in series. Each segment of the heating pipe and the tiered degassing and refining passage is provided with a heating device, and one end of the cooling pipe is fixedly connected to the stirring bucket.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

6. The degassing structure further includes a modified tube segment connecting the communicating tube segment and the refining tube segment.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

7. A partition plate is fixedly connected to one end of the refining tube segment away from the special-shaped tube segment, a through-hole is opened at the bottom on one side of the partition plate for interconnection with another communicating tube segment, and an exhaust device is fixedly connected to the top surface of the refining tube segment on the side closer to the partition plate.

7. The apparatus for producing glass substrates for displays according to claim 6.

8. The exhaust device is an exhaust pipe, and the tip of the exhaust pipe is configured to be bent downward.

8. The apparatus for producing glass substrates for displays according to claim 7.

9. The horizontal heights of the bottom surfaces of the refining tube segment, the communicating tube segment, and the special-shaped tube segment are the same, and the tops of the special-shaped tube segments are configured as inclined surfaces.

7. The apparatus for producing glass substrates for displays according to claim 6.

10. When the hierarchical degassing and refining apparatus is in use, the height of the glass melt inside the refining tube segment is L0, the height of the top surface of the refining tube segment is L1, and the height of the top surface of the communicating tube segment is L2, and the relationship is L1 > L0 > L2.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

11. The inner diameters of the communicating pipe segments in one or more of the defoaming structures are different from each other, and the inner diameter of the communicating pipe segment is smaller as it approaches the outlet direction of the hierarchical defoaming and fining device.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

12. The tin tank includes a tin tank pool and a tin tank top cover, one or more sets of space dividing plates fixedly attached to the inside of the tin tank top cover, the space dividing plates dividing the inside of the tin tank top cover into one or more top cover inner grooves, air supply pipes fixedly attached to the upper ends of all of the top cover inner grooves, an exhaust gap is opened on the parapet above the tin tank pool, one or more sets of exhaust pipes are fixedly attached inside the exhaust gap, an exhaust dividing plate is attached inside the exhaust gap to divide the exhaust gap into multiple independent grooves, and at least one exhaust pipe is provided in each of the independent grooves, and the air supply and exhaust control device can autonomously and controllably realize differentiated supply of protective gas to different areas and differentiated discharge of tin vapor from different areas by individually controlling the flow rate of each air supply pipe and the flow rate of each exhaust pipe.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

13. A transfer roll table between the tin tank and the annealing furnace is integrally connected to the annealing furnace, a top cover of the transfer roll table is integrally connected to the top cover of the annealing furnace, and a bottom case of the annealing furnace is integrally connected to the bottom case of the transfer roll table. One or more exhaust pipes are arranged at the top of the annealing furnace in the direction from the kiln entrance to the exit, a thermocouple is provided on one side of each exhaust pipe, and a liftable shielding curtain is provided on the other side of the exhaust pipe. A heating device and an annealing furnace control unit are provided inside the annealing furnace, and an electrical signal connection is formed between the thermocouple, the liftable shielding curtain, the heating device, and the annealing furnace control unit. Temperature data of different areas in the annealing furnace is sent to the annealing furnace control unit based on these values, and the annealing furnace control unit controls the shielding curtain to rise and fall to an appropriate height, while also controlling the exhaust volume of the exhaust pipe and the heating device in the annealing furnace.

3. The apparatus for producing glass substrates for displays according to claim 1 or 2.

14. The annealing furnace includes a heat-insulating pipe line with a purification and filtration device that supplies high-temperature exhaust gas from the tin tank into the annealing furnace, and a pipe line that can pass an inert protective gas into the annealing furnace.

14. The apparatus for producing glass substrates for displays according to claim 13.

15. A process for producing a display glass substrate using the apparatus for producing a display glass substrate according to any one of claims 1 to 14, the process comprising a raw material mixing step, a stepwise heating step, a tiered degassing and fining step, a tin tank forming step, an annealing step, cutting and post-processing steps, The stepwise heating melting furnace in the stepwise heating step includes a control unit, a first melting zone and a second melting zone along a flow direction of the glass melt, the first melting zone is provided with a heating element, and the second melting zone is provided with another heating element, and the control unit is capable of controlling heating of the first melting zone and the second melting zone, respectively; the hierarchical degassing and refining device in the hierarchical degassing and refining step includes a hierarchical degassing and refining passage, the hierarchical degassing and refining passage including one or more degassing structures for hierarchically discharging bubbles in different depth regions of the glass melt, the degassing structure including a communicating pipe segment and a refining pipe segment, the communicating pipe segment having an inner diameter smaller than that of the refining pipe segment; The control unit of the stepwise heating melting furnace controls and adjusts the temperature of the first melting section and the temperature of the second melting section to suit the degassing process of the stepwise degassing and refining passage. A production process for display glass substrates, characterized in that:

16. The temperature of the first fusion zone is greater than the temperature of the second fusion zone.

16. The production process for a display glass substrate according to claim 15.

17. The temperature difference between the first melting part and the second melting part is 5°C to 40°C, preferably 10°C to 30°C.

17. The production process for a display glass substrate according to claim 16.

18. The temperature of the first fusion zone may be 1650 to 1690°C, preferably 1650 to 1680°C, and more preferably 1660 to 1670°C; The temperature of the second fusion zone may be 1600 to 1650°C, preferably 1620 to 1640°C, and more preferably 1630 to 1640°C.

17. The production process for a display glass substrate according to claim 16.

19. The ratio of nitrogen gas to hydrogen gas in the protective gas in the tin tank is (94-100):(0-6), the ratio of hydrogen gas in the nitrogen-hydrogen protective gas increases stepwise from the upstream end to the downstream end, and the tank pressure of the tin tank is controlled to a positive pressure 10-30 Pa higher than standard atmospheric pressure.

16. The production process for a display glass substrate according to claim 15.

20. The glass raw material is preferably an alkali-free glass raw material, and contains, in weight percent: 59-75% SiO ２ , 12-20% Al ２ O ３ , 6-12% B ２ O ３ , 0.5-8% MgO, 2-10% CaO, 0.5-8% SrO, 0.1-3% ZrO ２ , 0.5-6% P ２ O ５ , 0.06 to 1% SnO ２ Contains ingredients of Here, SiO ２ +Al ２ O ３ is 71-85%, (MgO+CaO+SrO) / Al ２ O ３ is 0.3 to 1, The total amount of alkaline earth metal oxides is 3 to 15%; B ２ O ３ / (B ２ O ３ + ZrO ２ +P ２ O ５ ) is 0.5 to 1.0, (ZrO ２ +P ２ O ５ ) / (MgO+CaO+SrO) is 0.1 to 1.0 16. The production process for a display glass substrate according to claim 15.

21. An optical element is manufactured using a glass molded body manufactured by the production process for a display glass substrate according to any one of claims 15 to 20. A method for manufacturing an optical element.

22. A glass molded body manufactured by the production process for a display glass substrate according to any one of claims 15 to 20. Optical elements.

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