Method and system for controlling thickness of glass substrate

Abstract

The invention provides a thickness control method and system for a glass substrate, and the thickness control method comprises the following steps: controlling the fluidity of glass liquid in an overflow groove, and enabling the thickness of the far end of the glass substrate to be consistent with the thickness of the near end of the glass substrate; the liquid outlet amount of the feeding pipe and the traction speed of the traction mechanism are controlled, so that the maximum thickness of the middle area of the glass substrate is consistent with the thicknesses of the far end and the near end of the glass substrate; controlling the cooling mechanism to thicken the thickness thin point; and controlling the traction mechanism to pull the glass substrate to the target thickness. According to the invention, the first heating assembly and the second heating assembly are used as a primary adjustment mode and are assisted by the cold air pipe of the cooling mechanism and the traction speed of the traction roller, and an ordered and thorough process condition is formed according to the flowing characteristics of molten glass, so that the thickness adjustment control efficiency of the glass substrate is high, and the control effect is good.

Description

Technical Field

[0001] The present disclosure relates to the technical field of glass substrate production, and particularly to a method and system for controlling the thickness of a glass substrate. Background Art

[0002] Glass substrates have good flatness and light transmittance and are widely used in various fields such as display, touch, and optical technology fields. In different fields, different thickness requirements for glass substrates exist. Photoelectric display glass substrates produced by the overflow down-draw method, such as OLED (organic light-emitting semiconductor), LTPS (low-temperature polysilicon) glass substrates, and ultra-thin glass substrates with a thickness less than 0.1 mm, etc. When controlling the thickness of a glass substrate by the overflow down-draw method, the glass liquid is overflowed through an overflow brick and then pulled down by a traction roller. At the bottom of the overflow brick, the thickness of the glass substrate is changed by the cooperation of a cold air duct and a hot air duct, and a glass substrate is formed after annealing. The control process of the above thickness adjustment method is relatively single and cannot be effectively adjusted; in addition, due to uneven temperature, the produced glass substrate is prone to light and dark stripes, and thus cannot meet the high-quality requirements. Summary of the Invention

[0003] One technical problem to be solved by the present disclosure is: the poor control effect (presence of light and dark stripes) and low control efficiency caused by controlling the thickness of a glass substrate by the overflow down-draw method.

[0004] To solve the above technical problem, an embodiment of the present disclosure provides a method for controlling the thickness of a glass substrate. Wherein, taking the direction close to the feed pipe as the proximal end and the direction away from the feed pipe as the distal end, the feed pipe sends the glass liquid into the overflow groove of the overflow brick so that it flows from the proximal end to the distal end of the overflow groove. When the glass liquid overflows from the overflow groove, a glass substrate extends downward from the bottom of the overflow brick. The lower end of the glass substrate is pulled by a traction mechanism and passes through a cooling mechanism. The thickness control method includes the following steps:

[0005] Controlling the fluidity of the glass liquid at the distal end and the proximal end in the overflow groove to make the thickness of the distal end and the proximal end of the glass substrate consistent; controlling the liquid output of the feed pipe and the traction speed of the traction mechanism to make the maximum thickness in the middle area of the glass substrate consistent with the thickness of the distal end and the proximal end of the glass substrate; controlling the cooling mechanism to thicken the area of the glass substrate with a thickness less than the maximum thickness to be close to the maximum thickness; and controlling the traction speed of the traction mechanism to pull the glass substrate to the target thickness.

[0006] In some embodiments, in each step of the thickness control method, the traction speed of the traction mechanism is changed multiple times along the forming direction of the glass substrate.

[0007] In some embodiments, controlling the fluidity of the glass liquid at the distal end and the proximal end in the overflow tank includes: adjusting the power of the first heating component around the overflow tank, changing the temperature field of the glass liquid at the distal end and the proximal end of the overflow tank, and further changing the relative fluidity of the overflowed glass liquid between the distal end and the proximal end of the overflow tank.

[0008] In some embodiments, adjusting the power of the first heating component around the overflow tank includes at least one of the following: when the thickness of the distal end of the glass substrate is greater than that of the proximal end, reducing the power of the first heating component so that the degree of reduction in the fluidity of the glass liquid at the proximal end of the overflow tank is less than that at the distal end; when the thickness of the distal end of the glass substrate is less than that of the proximal end, increasing the power of the first heating component so that the degree of increase in the fluidity of the glass liquid at the proximal end of the overflow tank is less than that at the distal end.

[0009] In some embodiments, the overflow brick is arranged inside the muffle furnace, and the first heating component is a silicon carbide rod component arranged in the muffle furnace.

[0010] In some embodiments, controlling the liquid output of the feeding tube includes: adjusting the power of the second heating component at the orifice of the feeding tube, changing the fluidity of the glass liquid flowing out of the feeding tube, and further changing the amount of glass liquid flowing from the feeding tube to the overflow tank.

[0011] In some embodiments, adjusting the power of the second heating component at the orifice of the feeding tube includes at least one of the following: when the maximum thickness is greater than the thickness of the distal end or the proximal end, reducing the power of the second heating component to reduce the liquid output of the feeding tube and simultaneously increasing the traction speed; when the maximum thickness is less than the thickness of the distal end or the proximal end, increasing the power of the second heating component to increase the liquid output of the feeding tube and simultaneously reducing the traction speed.

[0012] In some embodiments, controlling the cooling mechanism to thicken the area of the glass substrate smaller than the maximum thickness to be close to the maximum thickness includes: detecting the thin point in the glass substrate, where the thin point is the area with a thickness less than the maximum thickness; aligning the vent of the cooling mechanism with the thin point; increasing the air intake of the vent aligned with the thin point until the difference between the thin point and the maximum thickness is a preset value.

[0013] In some embodiments, after obtaining the glass substrate with the target thickness, cutting off the edge portion of the glass substrate that does not meet the target thickness.

[0014] An embodiment of the present disclosure provides a thickness control system for a glass substrate, including: a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement the steps of the above-mentioned thickness control method for the glass substrate.

[0015] Through the above technical solutions, the thickness control method and system for the glass substrate provided by the present disclosure fully consider the process of the glass substrate from molten glass to forming, and propose a multi-step and multi-level thickness adjustment method. First, the fluidity of the molten glass in the overflow tank is controlled to make the thickness of both sides of the glass substrate consistent; secondly, the output volume of the molten glass in the feed pipe is controlled to make the maximum thickness in the middle area of the glass substrate consistent with the thickness of both sides; then, the local thin points of the glass substrate are thickened by controlling the cold air volume, and finally it is uniformly drawn to the target thickness. With a slight improvement to the existing equipment, the silicon carbide rod and the feed pipe are used as the primary adjustment methods, supplemented by the cold air pipe of the cooling mechanism and the traction speed of the traction roller. According to the flow characteristics of the molten glass, an orderly and meticulous process condition is formed. The fluidity of the molten glass is controlled by the silicon carbide rod assembly, the output volume of the molten glass is controlled by the heating wire, and the local thin points are thickened by the cooling mechanism only equipped with a cold air pipe. The entire process is adjusted in cooperation with the traction roller to achieve the thickness adjustment of the glass substrate. Fine adjustment is carried out in each step, and the steps are interrelated with each other, with high control efficiency. Moreover, the formed glass substrate has no bright and dark lines and is not easily broken, and the control effect is good. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Schematic diagram of the basic process flow of the thickness control method disclosed by the present invention;

[0018] Figure 2 Schematic diagram of the forming area of the glass substrate;

[0019] Figure 3 For Figure 1 specific process flow diagram;

[0020] Figure 4 Schematic diagram of the main part of the overflow equipment in the muffle furnace;

[0021] Figure 5 Schematic diagram of the structure of the feed pipe provided with a heating wire;

[0022] Figure 6 Schematic diagram of the thickness curve change before and after step S1;

[0023] Figure 7 Schematic diagram of the thickness curve change before and after step S2.

[0024] Explanation of the reference numerals in the drawings:

[0025] 1. Feeding pipe; 2. Support heat-insulating brick; 3. Overflow brick; 4. First heating component; 5. Second heating component; 6. Overflow tank. Specific embodiments

[0026] The following further describes in detail the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms, not limited to the specific embodiments disclosed herein, but including all technical solutions falling within the scope of the claims.

[0027] These embodiments are provided by the present disclosure to make the present disclosure thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, the components of materials, numerical expressions and values described in these embodiments should be construed as merely exemplary, rather than as limitations.

[0028] It should be noted that in the description of the present disclosure, unless otherwise specified, the meaning of "a plurality" is greater than or equal to two; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present disclosure. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

[0029] In addition, the "first", "second" and similar terms used in the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. The terms "including" or "comprising" and similar words mean that the elements before the word cover the elements listed after the word, and do not exclude the possibility of also covering other elements.

[0030] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances. When it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0031] All terms used in this disclosure have the same meanings as those understood by those of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as those, should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such herein.

[0032] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification.

[0033] Currently, the overflow down-draw method is generally used to produce glass substrates, that is, the molten glass liquid is introduced into the overflow groove of the overflow brick through a feeding pipe, and after overflow, it is formed from the bottom. Specifically, in the overflow down-draw method, the molten glass liquid is generally filled into the overflow groove of the overflow brick through a feeding pipe in a muffle furnace, and then the glass liquid slowly overflows from both sides of the overflow groove along the brick edge, forming a glass flow on both side surfaces of the overflow brick. When flowing to the brick tip at the bottom of the overflow brick, the glass liquid on both sides forms a piece of glass downward, and then is pulled by the traction roller below into a glass substrate. Among them, the feeding pipe can introduce the glass liquid from above the overflow brick, or can introduce the glass liquid from both sides of the overflow brick at the same time, or can introduce the glass liquid from one side of the overflow brick. When controlling the thickness, a cooling mechanism is provided at the brick tip at the bottom of the overflow brick. The cooling mechanism is provided with a hot air pipe and a cold air pipe. For the high thickness point in the glass substrate, the hot air pipe is used for blowing to reduce the thickness; for the low thickness point, the cold air pipe is used for blowing to increase the thickness, so as to make the thickness reach the standard thickness. After the glass can be formed, the air pipe is used to adjust the thickness again, which is relatively passive and easy to interrupt. Therefore, the above thickness control process is not good. For example, when the high thickness point and the low thickness point are close, the cold air and the hot air affect alternately, which easily causes bright and dark stripes to appear on the subsequently formed glass substrate. Only using the device at the brick tip to adjust the thickness, the adjustment means is single, and it cannot cope with various situations that occur during the production process, and the adjustment efficiency is not high.

[0034] Please refer to Figures 1 to 3 , in this embodiment, the feeding pipe introduces the glass liquid from the right side of the overflow brick. The direction close to the feeding pipe is the proximal end, and the direction far from the feeding pipe is the distal end. The feeding pipe sends the glass liquid into the overflow groove of the overflow brick, so that it flows from the proximal end to the distal end of the overflow groove. The glass liquid overflows from the overflow groove, passes through the overflow walls on both sides, and extends downward from the brick tip at the bottom of the overflow brick to form a glass substrate. The lower end of the glass substrate is pulled by the traction mechanism and passes through the cooling mechanism. It should be noted that since the glass substrate extends downward from the brick tip at the bottom of the overflow brick, during the forming process of the glass substrate, the proximal end of the overflow groove is consistent with the proximal end of the glass substrate, and the distal end of the overflow groove is consistent with the distal end of the glass substrate.

[0035] The method proposed by the present invention controls the thickness at different levels by various means throughout the process of solidifying and forming the glass substrate with a guide plate, which can achieve good control efficiency. At the same time, the cooling mechanism is arranged between the overflow brick 3 and the traction roller, and only the ventilation pipe with cold air is provided in the cooling mechanism, which can well avoid the generation of bright and dark stripes caused by too large a temperature difference between adjacent regions due to the simultaneous presence of hot and cold air, thereby avoiding obvious local dark stripes when light passes through the glass plate of the finished glass and improving production efficiency. In order to facilitate more intuitive and accurate thickness control, the present invention detects the lateral thickness of the glass substrate and plots it as a thickness curve. When adopting the thickness control method of the glass substrate, the thickness of the glass substrate can be adjusted with reference to the thickness curve. Among them, the lateral thickness is the thickness detected along the direction formed by the distal end and the proximal end. The thickness curve takes the thickness value as the ordinate and the distance from the discharge pipe as the abscissa. The highest point of the thickness curve is the maximum thickness, and the downward-bending part is the thin point of the thickness.

[0036] Based on the above process and referring to Figures 1 to 3 , the thickness control method of the glass substrate proposed by the present invention includes the following steps:

[0037] Step S1: Make the thickness of the distal end and the proximal end of the glass substrate consistent to form a basic thickness.

[0038] Control the fluidity of the glass liquid at the distal end and the proximal end in the overflow tank 6 to make the thickness of the distal end and the proximal end of the glass substrate consistent. Since the fluidity is the content of the glass liquid per unit time, the above control process is manifested as controlling the distribution amount of the glass liquid at the distal end and the proximal end in the overflow tank 6 to make the thickness of the distal end and the proximal end of the substrate consistent. The purpose of this step is to determine the basic thickness of the glass substrate to cope with the problem of the thickness slope of the glass substrate. There are two types of glass substrate thickness slopes. One is that the proximal end is thin and the distal end is thick, and the other is that the proximal end is thick and the distal end is thin. Please refer to Figure 4, which is a schematic diagram of the main part of the overflow device in the muffle furnace, including an overflow brick 3, a feeding pipe 1, a supporting insulation brick 2, and a first heating component 4. The overflow brick 3 is generally arranged in the muffle furnace, and the first heating component 4 is arranged around the overflow brick 3 to change the inner layer temperature of the glass liquid in the overflow trough 6. In this embodiment, the first heating component 4 is a silicon carbide rod (A1 rod) component, and the silicon carbide rod component is horizontally installed in the muffle furnace and arranged on both sides of the overflow wall of the overflow brick 3, generally used to keep the glass liquid flowing evenly. Each silicon carbide rod component includes 6 to 8 silicon carbide rods, and the power of each silicon carbide rod is 20,000 watts. Therefore, the power range of the silicon carbide rod component is 0 - 120,000 watts. The present invention adjusts the power of the first heating component 4 (i.e., the silicon carbide rod component) around the overflow trough 6 to change the temperature field of the glass liquid at the distal end and the proximal end in the overflow trough 6 to different degrees. The change in the temperature field will cause the fluidity of the glass liquid to change, and then change the relative fluidity of the overflowing glass liquid between the distal end and the proximal end of the overflow trough 6, ultimately making the thickness of the distal end and the proximal end of the glass substrate consistent. Specifically, when the thickness slope of the glass substrate is thin at the proximal end and thick at the distal end, that is, when the thickness of the distal end of the glass substrate is greater than that of the proximal end, the power of the first heating component 4 is reduced. At this time, the inner layer temperature of the glass liquid in the overflow trough decreases simultaneously, and the overall fluidity decreases. However, since the outer layer temperature of the glass liquid at the proximal end is higher than that at the distal end (after the glass liquid flowing out of the feeding pipe contacts the air and enters the overflow brick, it serves as the outer layer temperature of the glass liquid in the overflow trough, and the outer layer temperature gradually decreases as the flow distance increases), the change degree of the temperature difference between the inside and outside at the proximal end is less than that at the distal end. Therefore, the reduction degree of the fluidity at the proximal end is less than that at the distal end, so that the amount of the overflowing glass liquid at the proximal end of the overflow trough 6 is increased compared with the distal end, and then the increase degree of the thickness of the proximal end of the glass substrate is greater than that of the distal end until the thickness of the proximal end and the distal end is consistent; on the contrary, when the thickness slope is thick at the proximal end and thin at the distal end, that is, when the thickness of the distal end of the glass substrate is less than that of the proximal end, the power of the first heating component 4 is increased. At this time, the inner layer temperature of the glass liquid in the overflow trough increases simultaneously, and the overall fluidity increases. However, since the outer layer temperature of the glass liquid at the proximal end is higher than that at the distal end, the change degree of the temperature difference between the inside and outside at the proximal end is less than that at the distal end. Therefore, the increase degree of the fluidity at the proximal end is less than that at the distal end, so that the amount of the overflowing glass liquid at the distal end of the overflow trough 6 is increased compared with the proximal end, and then the increase degree of the thickness of the distal end of the glass substrate is greater than that of the proximal end until the distal end and the proximal end are consistent. The power of the first heating component 4 can be adjusted repeatedly, such as increasing or decreasing 100 - 2000 watts each time, and finally making the thickness of the proximal end and the distal end of the glass substrate consistent. Please refer to Figure 6 , which is a schematic diagram of the thickness curve change after step S1. It can be seen that after adjustment, the heights of the distal end and the proximal end are the same, and the thickness values of the proximal end and the distal end are equal.

[0039] Step S2: Make the maximum thickness of the glass substrate consistent with the thicknesses of the distal end and the proximal end.

[0040] After step S1, the thicknesses at both ends of the glass substrate are consistent, facilitating the subsequent adjustment in step S2. At this time, control the liquid output of the supply pipe 1 and the traction speed of the traction mechanism to make the maximum thickness in the middle area of the glass substrate the same as the thicknesses at the distal end and the proximal end of the glass substrate. In the present invention, by adjusting the power of the second heating component 5 at the nozzle of the supply pipe 1, the fluidity of the glass liquid flowing out of the supply pipe 1 is changed, thereby changing the amount of glass liquid flowing from the supply pipe 1 to the overflow tank 6. Please refer to Figure 5 , which is a schematic structural diagram of the supply pipe 1 provided with heating wires. The second heating component 5 is arranged at the nozzle or the entire pipe body of the supply pipe 1 to change the outer layer temperature of the glass liquid in the overflow tank 6. In this embodiment, the second heating component 5 is a heating wire wound around the nozzle or the pipe body of the supply pipe 1 (i.e., the L pipe). The heating wire of the L pipe originally keeps the pipe at a high temperature to prevent the flowing glass liquid from cooling. In the present invention, specifically, when the maximum thickness is greater than the thickness at the distal end or the proximal end, reduce the power of the second heating component 5, increase the temperature difference between the upper and lower layers of the glass liquid in the overflow brick 3, thereby reducing the fluidity of the glass liquid, reducing the liquid output from the supply pipe 1 to the overflow tank 6, reducing the glass liquid in the middle area of the glass substrate, and at the same time increasing the traction speed, that is, increasing the glass liquid distribution at both ends of the glass substrate relative to each other, so that the maximum thickness is the same as the thicknesses at the distal end and the proximal end; on the contrary, when the maximum thickness is less than the thickness at the distal end or the proximal end, increase the power of the second heating component 5, thereby increasing the fluidity of the glass liquid, increasing the liquid output from the supply pipe 1 to the overflow tank 6, increasing the glass liquid in the middle area of the glass substrate, and at the same time reducing the traction speed, that is, increasing the glass liquid distribution in the middle area of the glass substrate, to make the maximum thickness the same as the thicknesses at the distal end and the proximal end. The power of the second heating component 5 can be repeatedly adjusted, such as increasing or decreasing by 0 - 7000 watts each time, and finally making the maximum thickness in the middle area of the glass substrate the same as the thicknesses at the proximal end and the distal end. The distance between the distal end and the proximal end can be 100 - 600 mm. Please refer to Figure 7 , which is a schematic diagram of the thickness curve change after step S2. It can be seen that after adjustment, the highest point in the middle area is at the same height as the distal end and the proximal end, that is, the maximum thickness value in the middle area is equal to the proximal thickness value and the distal thickness value.

[0041] Step S3: Adjust the local thickness.

[0042] Through the adjustment of steps S1 to S2, the basic thickness of the glass substrate has been formed. In this step, local adjustment is required to control the cooling mechanism so that the area of the glass substrate smaller than the maximum thickness thickens to be close to the maximum thickness. Adjust the air volume of the air ducts in the cooling mechanism to achieve the target thickness extreme value required for quality. The cooling mechanism can be installed on both the left and right sides of the muffle furnace. By compressing the intake air flow of the air ducts in the cooling mechanism, the local temperature in the area where the intake air volume increases decreases, thereby controlling the viscosity of the local glass liquid to thicken the locally thinner area of the glass plate. Specifically, in the present invention, the cooling mechanism only has cold air vents. The specific process is as follows: According to the thickness value information, the thin points in the glass substrate are detected. The thin points are areas where the thickness is less than the maximum thickness, and can be strip-shaped or dot-shaped areas. The length of the strip-shaped area can be 10 to 100 mm; align the vents of the cooling mechanism with the thin points, and the positions of the vents can be flexibly adjusted, so as to thicken the thin points locally in a targeted manner; increase the intake air volume of the vents aligned with the thin points, so that the temperature of the thin points corresponding to the vents decreases, and then the glass liquid is more likely to solidify here until the difference between the thin point and the maximum thickness is a preset value. In this embodiment, the target thickness extreme value, that is, the preset value is not greater than 0.008 mm. The intake air volume adjusted each time is 0 - 60 LN / min.

[0043] Among them, the cooling mechanism of the present invention uses cold air control throughout the process and does not need to install a hot air duct to heat it, which has lower costs and will not appear bright and dark stripes. Through the adjustment of steps S1 to S2, the maximum thickness has been consistent with the thicknesses at the distal end and the proximal end. At this time, only thickness thin points exist, and only the thickness thin points need to be found and thickened, that is, the area with a smaller value than the maximum thickness is found. In the prior art, both thickness thin points and thick points exist in the obtained glass substrate, and local adjustments need to be made for the thickness thin points and thick points respectively. For example, by blowing hot air through an air duct equipped with a platinum heating wire, the thick points in the glass plate are blown thin. When the hot air duct heats the glass plate, the temperature is higher closer to the middle, and the heat acting on the glass plate will cause a concave lens phenomenon in the corresponding local area of the glass substrate, resulting in obvious local bright and dark stripes when light passes through the glass plate of the finished product, causing product scrapping. In addition, the hot air duct is easily damaged and has a high cost. The present invention controls the thickness formation process of the glass substrate from the source, avoids the appearance of difficult-to-handle thickness high points, thereby eliminating unnecessary steps and costs, reducing or not installing hot air ducts subsequently, effectively solving the generation of bright and dark stripes caused by excessive temperature difference between adjacent areas of the glass substrate, and effectively improving the quality of the glass substrate.

[0044] Step S4: Adjust the average thickness value of the glass substrate.

[0045] After the processing steps from S1 to S3 above, the glass substrate is basically of uniform thickness. At this time, simple processing is required to draw the glass substrate to the target thickness while ensuring uniform stress. The present invention controls the drawing speed of the drawing mechanism to draw the glass substrate to the target thickness. Specifically, the drawing speed is changed by adjusting the motor speed of the drawing roller. The drawing roller is the main equipment in the overflow down-draw method to make the glass substrate reach the thickness standard. After the overflow thickness of the glass substrate is uniform, according to the required thickness of the product, which is 0.3 - 0.6 mm, the rotation speed of the drawing roller is adjusted to meet the product requirements. When the rotation speed of the servo motor of the drawing roller is reduced, the drawing linear speed of the glass plate can be reduced, and the average thickness of the glass substrate will increase on the premise of a stable glass liquid incoming flow rate; conversely, when the rotation speed of the servo motor of the drawing roller is increased, the average thickness of the glass substrate can be reduced, and finally the required average thickness is achieved.

[0046] Step S5: Cut the edges of the glass substrate with the target thickness.

[0047] After obtaining the glass substrate with the target thickness, the edge portions that do not meet the target thickness in the glass substrate are cut off. After step S4, the middle region can basically reach the target thickness, but there may be edge portions that do not meet the target thickness, so the unqualified edge regions need to be cut.

[0048] In addition, in order to achieve a better thickness control effect, in each step of the thickness control method, the drawing speed or the drawing direction of the drawing mechanism can be changed multiple times along the forming direction of the glass substrate to achieve the same thickness at the distal end and the proximal end of the glass substrate in step S1, the same thickness at the maximum thickness, the distal end, and the proximal end of the glass substrate in step S2, adjust the local thickness in step S3 to thicken the thinner points, and adjust the average thickness value of the glass substrate in step S4. At the same time, the above steps S1 to S4 can be carried out in sequence. They can also be repeated in a certain order. For example, after step S1 is carried out first, if the maximum thickness has been the same as the thickness at the distal end and the proximal end, step S2 can be skipped and step S3 and step S4 can be directly carried out.

[0049] The thickness control system of the glass substrate proposed by the present invention includes: a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the steps of the above-mentioned thickness control method of the glass substrate.

[0050] The thickness adjustment process of the traditional overflow method generally focuses on the rotation speed of the traction roll. That is, after the glass can form a plate, the air duct is adjusted for thickness, which is relatively passive and prone to interruption. In the traditional method, the L-tube and the A1 rod only play a stabilizing and auxiliary role and are not adjusted too much. In the present invention, the A1 rod and the L-tube are used as the primary adjustment method, and process conditions are formed according to the flow characteristics of the molten glass. This makes the thickness adjustment of the glass substrate not blind and highly efficient. The thickness control method adopted in the present invention first adjusts the overall thickness curve of the glass substrate through steps S1 to S2, and then adjusts the local thickness through step S3 to reach the required average thickness. This control process can prevent the thickness range from being too large and prevent the occurrence of abnormal plate breakage caused by too thin local thickness during the process of increasing the rotation speed of the traction roll in step S4, which may cause the glass plate to be torn. When the average thickness is achieved and the thickness range changes beyond the required thickness extreme range, the above steps can be repeated until the thickness quality requirements are met, greatly improving the production stability and production efficiency. At the same time, the present invention makes full use of various equipment in the muffle furnace, makes slight improvements to it, reduces the cost, and can also achieve better thickness adjustment effects.

[0051] So far, the embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details well known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0052] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present disclosure. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way.

Claims

1. A method for controlling the thickness of a glass substrate, wherein: The direction close to the feed pipe (1) is the proximal end, and the direction away from the feed pipe (1) is the distal end. The feed pipe (1) delivers the glass liquid to the overflow groove (6) of the overflow brick (3), so that it flows from the proximal end to the distal end of the overflow groove (6). When the glass liquid overflows the overflow groove (6), a glass substrate extends downward from the bottom of the overflow brick (3). The lower end of the glass substrate is pulled by a pulling mechanism and passes through a cooling mechanism. The thickness control method comprises the following steps: Controlling the fluidity of the glass liquid at the distal end and the proximal end of the overflow trough (6) so that the thickness of the distal end and the proximal end of the glass substrate are consistent; Controlling the liquid output of the feed pipe (1) and the pulling speed of the pulling mechanism so that the maximum thickness of the middle area of ​​the glass substrate is consistent with the thickness of the distal end and the proximal end of the glass substrate; Controlling the cooling mechanism so that a region of the glass substrate that is thinner than the maximum thickness increases in thickness to a thickness close to the maximum thickness; and The pulling speed of the pulling mechanism is controlled to pull the glass substrate to a target thickness.

2. The thickness control method according to claim 1, characterized in that: In each step of the thickness control method, the pulling speed of the pulling mechanism is changed multiple times along the forming direction of the glass substrate.

3. The thickness control method according to claim 1, characterized in that: The controlling of the fluidity of the glass liquid at the distal end and the proximal end of the overflow trough (6) comprises: The power of the first heating component (4) around the overflow groove (6) is adjusted to change the temperature field of the glass liquid at the far end and the near end of the overflow groove (6), thereby changing the relative fluidity of the glass liquid overflowing between the far end and the near end of the overflow groove (6).

4. The thickness control method according to claim 3, characterized in that: The step of adjusting the power of the first heating component (4) around the overflow tank (6) comprises at least one of the following: When the thickness of the far end of the glass substrate is greater than that of the near end, the power of the first heating component (4) is reduced so that the fluidity of the glass liquid at the near end of the overflow trough (6) is reduced less than that at the far end; When the thickness of the far end of the glass substrate is smaller than that of the near end, the power of the first heating component (4) is increased so that the fluidity of the glass liquid at the far end of the overflow trough (6) increases to a greater extent than that at the near end.

5. The thickness control method according to claim 3, characterized in that: The overflow brick (3) is arranged inside the muffle furnace, and the first heating component (4) is a silicon carbon rod component arranged inside the muffle furnace.

6. The thickness control method according to claim 1, characterized in that: The controlling of the liquid output of the feed pipe (1) comprises: The power of the second heating component (5) at the mouth of the feed pipe (1) is adjusted to change the fluidity of the glass liquid flowing out of the feed pipe (1), thereby changing the amount of glass liquid flowing from the feed pipe (1) to the overflow tank (6).

7. The thickness control method according to claim 6, characterized in that: The power of the second heating assembly (5) at the nozzle of the feed pipe (1) is adjusted, including at least one of the following: When the maximum thickness is greater than the thickness at the distal end or the proximal end, the power of the second heating component (5) is reduced to reduce the amount of liquid discharged from the feed pipe (1), while increasing the pulling speed; When the maximum thickness is less than the thickness at the far end or the near end, the power of the second heating component (5) is increased to increase the liquid output of the feed pipe (1) while reducing the pulling speed.

8. The thickness control method according to claim 1, characterized in that: The controlling the cooling mechanism so that a region of the glass substrate that is less than the maximum thickness increases in thickness to be close to the maximum thickness comprises: Detecting a thin spot in the glass substrate, wherein the thin spot is an area with a thickness less than the maximum thickness; Align the vents of the cooling mechanism to the thin spots; The air intake of the vent aimed at the thin spot is increased until the difference between the thin spot and the maximum thickness is a preset value.

9. The thickness control method according to claim 1, characterized in that: After obtaining the glass substrate of the target thickness, the edge portion of the glass substrate that does not meet the target thickness is cut off.

10. A glass substrate thickness control system, characterized in that: include: A memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method according to any one of claims 1 to 9.

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