TW202406862A - Thermal management of variable thickness glass ribbon - Google Patents

Abstract

A glass ribbon processing apparatus to produce a glass ribbon having a first portion with a first thickness immediately adjacent to a second portion with a second thickness, the apparatus comprising a water wick contacting the first portion of the glass ribbon to cool the first portion as the glass ribbon travels passed the water wick, wherein the first thickness is greater than the second thickness.

Description

Thermal management of variable thickness glass ribbons

Cross-references to related applications

This application claims the priority rights and interests of the US Provisional Application No. 63/332773 filed on April 20, 2022 in accordance with the patent law. This article relies on the content of the US Provisional Application and the content of the US Provisional Application is cited in full. are incorporated into this article.

The present disclosure relates to devices and methods that provide preferential cooling or heating of precise areas within a continuous ribbon of glass. The disclosed apparatus and methods can provide control of the temperature of the glass ribbon to ensure that the temperature difference between thick and thin areas remains at or near zero. Temperature must be controlled in this way to avoid thermally induced shape (warpage) and residual stresses. The disclosed devices and methods can be applied before and after the viscoelastic zone.

Any glass or housing design of the back cover or electronic components of some smartphones and mobile devices has an uneven thickness that is thicker in the camera area than other parts, which allows for improvements in camera lens design (see, for example, U.S. PG Pub.2019/0364179 A1). For example, the glass thickness can be 1.5 to 3.0 mm in thicker parts and less than 0.8 mm in other places. To create thicker sections of a device back cover or housing, relatively thick glass sheets can be ground, polished, and polished to define thicker and thinner areas. In this case, in order to produce a glass article with a thickness of 1.6 mm in thicker areas and a nominal thickness of 0.6 mm elsewhere, a glass plate with a thickness of 1.9 mm can be used. That is, 0.3 mm of material will be removed from the thicker section, and 1.3 mm of material will be removed from the thinner section. This method has low glass utilization, is time-consuming, high-cost, low-efficiency, and not environmentally friendly.

In an alternative method of forming a glass article with uneven thickness, two glass substrates can be fused together (see, eg, U.S. PG Pub. 2017/0210111 A1). For example, a 25 mm x 25 mm x 1.0 mm piece of glass can be fused into a larger 70 mm x 150 mm x 0.6 mm piece of glass by bonding or pressing them together at high temperatures. This method improves the utilization of glass, but consumes a lot of energy, can lead to the formation of bubbles at the melting interface, and is costly and time-consuming.

When the grinding process is not cost-effective and creates too much waste, and when fusing two pieces of glass together is not a viable option, another solution is to define a continuous glass ribbon with the desired thickness difference. Producing glass ribbons with varying thicknesses may require significant temperature differences between thicker and thinner sections. Therefore, in order to produce such a glass ribbon with low stress and warpage, it is required to be able to preferentially cool the thicker portion at a prescribed rate different from the cooling rate of the base ribbon (or the thinner portion of the glass ribbon). There may also be a requirement to preferentially heat the base strip (or thin areas) to slow down its normal cooling rate relative to thicker sections.

This disclosure provides a solution to this technical challenge.

To overcome the problems described above, embodiments of the present disclosure provide apparatus and methods that manage thick-to-thin and top-to-bottom temperature gradients by cooling thinner portions at a higher temperature than Rate cooling of thicker portions of the glass ribbon minimizes stress and warpage in variable thickness glass sheets. Cooling can be performed via convection and/or radiation and from the top and/or bottom of the glass ribbon. Optionally, localized heating can be used with preferential cooling to control desired temperature parameters within the glass.

The described embodiments may be applied to hot glass ribbons traveling in lehrs and/or controlled cooling apparatus (CCA). CCA is an improved annealing furnace, or roller hearth annealing furnace, or roller kiln for producing glass ribbons. The present disclosure provides a solution to the thermal management challenges that must be overcome to produce glass ribbons of variable thickness.

Without the currently described thermal management methods, the stresses generated in glass ribbons with variable thicknesses would be too high. This would require scoring the plate, cutting out highly stressed sections from the plate, or providing additional finishing processes to produce the glass of the required size, shape and thickness. Alternative methods of reducing stress in the glass ribbon are to significantly increase the annealing furnace length or to add an annealing step. Both methods involve significant cost and space requirements.

According to one embodiment of the present disclosure, a glass ribbon processing apparatus produces a glass ribbon having a first portion of a first thickness adjacent a second portion of a second thickness, the apparatus including a water core contacting the first portion of the glass ribbon to when The glass ribbon cools the first portion as it travels through the water core, wherein the first thickness is greater than the second thickness. wherein the first portion is cooled at a first rate and the second portion is cooled at a second rate, wherein the first rate is greater than the second rate.

In one embodiment, the first and second portions are oriented longitudinally along the length of the glass ribbon.

The glass ribbon processing equipment may further include a heater located upstream of the water core.

In one embodiment, the water core is a fabric strip and is fixed at one end above the glass strip.

In one embodiment, the water core is circular and rotates about an axis and is below the glass ribbon as it travels in a horizontal direction.

In one embodiment, the water core is attached to a substantially planar plate.

According to another embodiment, a glass ribbon processing apparatus produces a glass ribbon having a variable thickness, the apparatus including an atomizer to spray coolant and/or cooling air over thicker portions of the glass ribbon to spray the fog as the glass ribbon travels through the fog. Cool the thicker part of the glass ribbon when using the vaporizer.

According to another embodiment, a glass ribbon processing apparatus produces a glass ribbon having a variable thickness, the apparatus including a heater to heat the thinner portions of the glass ribbon as it travels past the heater. In one embodiment, the heaters are two heaters positioned symmetrically across the width of the glass ribbon. In one embodiment, the heaters are two heaters, one above and one below the glass ribbon.

According to another embodiment, a glass ribbon processing apparatus that produces glass ribbons of variable thickness includes air rods to force air onto a portion of the glass ribbon as it travels past the air rods. In one embodiment, the gas rod is below the glass ribbon. In one embodiment, air rods support the glass ribbon. In one embodiment, air rods force cooling air to thicker portions of the glass ribbon. In one embodiment, the air includes steam and is forced onto the thinner portions of the glass ribbon.

According to one embodiment, a glass ribbon processing apparatus produces a glass ribbon including a first thickness and a second thickness, the apparatus including: a roller to support the glass ribbon as it travels past the roller; and a nozzle to force cooling air to be injected The arrival roller contacts a portion of the glass ribbon where the first thickness is greater than the second thickness. In one embodiment, the portion of the roller that contacts the glass ribbon corresponds to the first thickness.

The above and other features, elements, characteristics, steps and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.

Glass ribbon geometries including thinner portions and thicker portions are made possible by the apparatus and methods described in this disclosure. Drawn glass ribbon geometries can include a certain width, with some portions being thicker than others. For example, the thicker portion can be in the center of the glass ribbon. Depending on the situation, there may be more than one thicker section spaced across the width of the glass ribbon. Geometric shapes are usually designed for a specific product.

Conventional thermal management within the lehr and/or CCA results in the thicker section being consistently hotter than the thinner base glass throughout the controlled cooling section. This constant thermal gradient between thicker and thinner parts during strip cooling, although reasonably well managed by controlling the annealing furnace, causes high stresses and warpage in the molded product . This leads to an urgent need for priority thermal management tools used with annealing furnaces to reduce thermal gradients and reduce the resulting stresses.

An important factor is to provide additional cooling via preferential thermal tools so that the glass ribbon reaches nearly the same temperature in thicker and thinner sections to keep the thick-to-thin temperature difference (ΔT or DT) close to zero. Preferential cooling of thicker parts of the glass ribbon can be combined with preferential heating of thinner parts. Heating of thinner parts can be achieved by locally heating tools or by keeping the entire annealing furnace at a higher temperature than the thinner parts (while cooling tools preferentially cool the thinner parts).

Cooling flow, stress and warpage data show that as the thicker section is cooled, the temperature difference between the thicker and thinner sections decreases and the stress in the glass ribbon also decreases. As can be seen from the data, the functionality of the cooling unit can be optimized based on the specific application and expected results.

Cooling may be provided using any combination of techniques including forced air (convection), radiation and conduction. Cooling system design includes considerations including emissivity, the ideal gas law and expansion of hot air, exhaust of hot air from the manufacturing plant, and personnel safety.

Any type of cooling (convective, radiative, conductive, and combinations), heating, or heating/cooling can be provided such that each device providing the treatment can be independently moved and positioned to align with any portion of the glass ribbon. Any device can be placed in the center of the glass ribbon to cover wider and thicker sections, or the devices can be spread out towards the edges of the glass ribbon to cover narrower edge strip configurations. Any device can be positioned independently above, below, to the side, or parked aside relative to the glazing strip when not in use, and can be placed into position manually or by an automatic electromechanical positioning system. Optionally, any number of positions of any number of devices for heating and/or cooling can be positioned and preprogrammed by automation so that different configurations of the glass ribbon process can be repeatable.

As shown in Figure 1A, the water core 10 can be used to preferentially cool thicker areas of the traveling glass ribbon 20. As shown in Figure 1A, when the glass ribbon 20 moves from left to right, the water core 10 can be suspended on the stand 30 suspended above the glass ribbon conveying system and placed in contact with the glass ribbon 20, and The glass strip 20 is dragged as it travels. Thus, thicker areas can be cooled as a continuous strip in the portion of the glass ribbon 20 in contact with the water core 10 .

Alternatively, as shown in Figure 1B, the glass ribbon may include intermittently repeating thicker regions rather than continuous strips or portions of the width of the glass ribbon. For example, Figure 1B illustrates a glass ribbon 25 that includes intermittently repeating thicker regions 28. As shown, thicker region 28 may be shaped as a substantially rectangular shape, although other shapes are possible. Figure 1B also shows a cooling manifold 40 above the glass ribbon 20 for cooling only the thicker portion 28.

The cooling manifold 40 may be substantially planar and include a water connection fitting 42 connecting the manifold 40 to a water source, a water channel 44 that directs water from the water connection fitting 42 , and a core that absorbs water directed thereto via the water channel 44 50. The water manifold 40 is positioned above the glass ribbon 20 such that the thicker region 28 of the glass ribbon 20 contacts the core 50 as the glass ribbon 20 travels through the manifold 40 . The manifold 40 is spaced apart from the glass ribbon 20 such that the thicker areas 28 contact the core 50 but the thinner areas do not. Therefore, manifold 40 can cool thicker regions 28 without cooling thinner regions of glass ribbon 20 .

The core material allows precise deposition of water onto the surface of the glass ribbon being cooled. The water flow rate is controlled and adjusted through a valve so that the evaporation rate matches the water flow rate. This ensures maximum heat dissipation without uncontrolled delivery of excess water to the glass ribbon. For example, by dragging the water core 10 in the manner shown in Figure 1A, the temperature difference (ΔT or DT) from thicker to thinner is reduced by approximately 8°C. It is desirable to reduce this temperature difference as much as possible without cooling the thinner portions of the glass ribbon or adding stress to the glass ribbon.

The water core can be made of any absorbent material suitable for the temperature and material being cooled. For example, the water core can be made from woven silica yarn. The length, width, thickness and material of the core can be adjusted to meet the cooling needs of the glass ribbon product.

Figure 2 illustrates the use of a wicking wheel as an alternative to the water core 10 shown in Figure 1A to cool thicker areas in the glass ribbon according to another embodiment. Wicking wheels are perforated liquid distribution wheels wrapped with water core material. While any number is possible, the top portion of Figure 2 shows an arrangement of two wicking wheels used to cool the thicker center strip of continuous glass ribbon. The wicking wheel works on the same principle as using the soaked cloth of the water core 10 to deposit water precisely onto the surface of the glass ribbon being cooled. Wicking wheels have several advantages over water cores 10. In particular, the wicking wheel can be deployed to cool the underside of the glass ribbon because it does not rely on gravity to keep the wicking material wet and in contact with the glass ribbon. As with the water core 10, the water flow rate supplied via the wicking wheel is throttled so that the flow rate matches the evaporation rate for optimal cooling with maximum control. Thicker parts of the glass ribbon are hotter than thinner parts. As mentioned before, it is desirable to reduce DT to 0 ^o C as much as possible without overcooling the thicker sections.

The upper portion of Figure 2 shows that the wicking wheel can be supported by the frame and held in place relative to the glass ribbon. Each wicking wheel is free to rotate about an axis of rotation defined by a shaft that doubles as a water supply pipe. The water supply can be attached to a swivel at one end of the shaft. The lower part of Figure 2 is a side view of the frame and wicking wheel, showing the swivel attached to the water supply, the pipe that delivers the water to the wicking wheel, and the two bearings.

Figures 3 to 5 illustrate an atomization device for cooling a thicker area in a glass ribbon according to another embodiment of the present disclosure. The atomizing device directs the atomized liquid onto the glass strip. The liquid may be water, a mixture with water, or any other suitable fluid.

Figure 3 is a side view of an atomizing device that sprays air and/or liquid on a glass ribbon traveling in the direction from left to right. Figure 4 is another view looking upstream of the atomizing device. Figure 5 is an image of the spray from the atomizer device from the transmission angle. As shown, the atomizing device may include a frame or stand that supports the atomizing sprayer. Although three atomizing sprayers are shown, any number is possible. The frame may include a mechanism to adjust the height or distance of the atomizing sprayer from the glass strip. Each atomizing sprayer can be surrounded by an air purifying enclosure with a heat shield.

Each atomizing sprayer may also include a coupling for turning the atomizing sprayer's actuation air on and off, a coupling for atomizing air, a coupling for liquid (ie, water or other coolant) Adapters, mechanisms for adjusting the liquid flow rate, and nozzles. The atomizing air can be continued all the time, but the liquid spray is only introduced when needed. The use of actuated air allows the valve to control the positioning of the cooling liquid at the nozzle, which allows for more precise timing of the liquid spray and reduces dripping. As shown in Figure 5, the nozzle can be replaced to spray cooling air or liquid. The nozzle can output air and/or liquid in a fan shape or other suitable geometry. Optionally, each atomizing sprayer can be adjusted to be different from the other atomizing sprayer so that the output pattern is different, or one sprays air while the other sprays liquid. Optionally, an atomizing device can be located above the glass ribbon before it enters the CCA. condition Thin T(C) Thick T(C) DT(C) Pressure at the strip (MPa) Warp across width* (mm) benchmark 660 700 +40 6.7 <0.1 mm Condition 2 620 640 +20 4.2 ~5 mm Condition 1 620 620 0 3.75 ~3.5 mm Condition 3 620 600 -20 6.25 <0.3mm

Table 1

Table 1 includes empirical data obtained on glass ribbons prior to entering CCA, which demonstrates the effects of glass thermals on stress and warpage*. The base condition is no cooling, while conditions 1 through 3 each have different levels of cooling, all at the same travel rate. Warping* is bending or overall warping, not curtain warping, which is caused by mechanical sources. Table 1 includes the data acquisition conditions, the temperature of the thinner part of the glass ribbon, the temperature of the thicker part of the glass ribbon, the temperature difference between the thinner part and the thicker part (all temperatures are in degrees Celsius), on the thicker glass strip Measured stress (in MPa), and warpage* (in mm) across the width of the glass ribbon.

Empirical conditions include an atomizing device with three continuous atomizing sprayers located above the top surface (A-side) of the glass ribbon before it enters the CCA. The cooling setup is shown in Figure 5, with three atomizing sprayers arranged in a row above a thicker strip of glass ribbon in front of the CCA entrance, on the right side of the picture. The thicker strip is 80 mm wide, the thinner part of the glass strip is approximately 2.0 mm thick, and the thickness difference between the thicker strip and the thinner part is approximately 0.35 mm. Pre-CCA thermal data was captured using a thermal imaging camera. Table 1 shows the effect of spray cooling on DT, stress and warpage. As shown in Table 1, water spray cooling is very effective in cooling thicker strips and reducing DT from +40°C to -20°C (ie, the effect of 60°C).

As shown in Table 1, the spray cooling provided in Condition 1 (Cond 1) and Condition 2 (Cond 2) reduced stress in the thicker strips. However, Cond 3 provides similar stresses to Baseline. The optimal cooling level will depend on the strip geometry and thermal parameters. For example, extrapolating to higher thickness increments of 0.8 mm, the thick-to-thin DT at the entrance to the CCA might be around 80°C without any preferential cooling of the strip. In this case, cooling conditions with a DT of 60 to 100°C may provide minimal stress.

Note that conditions 1 and 2 with the lowest stress both result in increased warpage. Increased warpage can be avoided by applying cooling while keeping the glass ribbon constrained to a flat surface, such as using a vacuum conveyor.

Figure 6 shows the stress birefringence measurement of a thicker area experimentally cooled by water spray (conditions are the same as in Table 1). A two-fluid atomizing sprayer is used to selectively cool thicker portions of the glass ribbon. Advantages of dual-fluid atomizing sprayers include precise control of water and air flow rates, the ability to cycle on/off for discontinuous cooling, and the ability to tune droplet size to reduce the Leidenfrost effect and improve heat dissipation. A fan spray pattern of nozzles is used to promote a uniform cooling rate across the patch.

The left image shown in Figure 6 is of the uncooled glass ribbon, with a baseline condition of 6.7 MPa stress. The image on the right shown in Figure 6 is of a glass ribbon spray cooled over a thicker section. The image on the right is from Condition 2 in Table 1, which has a stress of 3.75 MPa.

The birefringence data in Figure 6 illustrates the differences in optical properties of different parts of the glass ribbon and represents stress differences. Birefringence: S1-S2 = delay/(thickness*SOC) S1-S2 = Difference of in-plane principal stresses Delay unit: mm SOC (stress optical coefficient) ~ 3 nm/MPa-mm

In another embodiment of the present disclosure, Figure 7 illustrates a heater that can be used to preferentially heat portions of a glass ribbon to reduce the thermal gradient between thicker portions and thinner portions. The heater is shown positioned above the glass ribbon before it enters the CCA, but any suitable location is possible, including below the glass ribbon. In this example, there are two sets of heaters, each with two heating elements, placed symmetrically on each side of the glass ribbon and away from the thicker central strip area to provide primarily to the outer, thinner portions of the glass ribbon. Prioritize heating.

Figure 8 shows the arrangement and relative spacing of four heaters positioned relative to a 330 mm wide glass strip with a thicker center strip of 80 mm width in a real trial. In Figure 8, the glass ribbon moves from right to left between the viscous turning VT and CCA, where at the viscous turning VT, the glass ribbon moves from vertical to horizontal movement.

Analytical estimates and numerical modeling demonstrate the effectiveness of the heater and demonstrate the advantages of this preferential heating approach over a device setup without such a heater. To evaluate the effectiveness of the heater, Figure 9 shows the relationship between heater face temperature and glass ribbon temperature, where a 1.3 mm thick glass ribbon passes through a 12” long heater. Two situations are shown in this graph: The glass ribbon enters the heater at 850°C or 750°C, both with a glass flow of approximately 1400 lbs/hr and a velocity of approximately 0.14 m/s. The total width of the glass ribbon is 330 mm, with a thicker center strip The width is 80 mm. The thickness of the thinner part is 1.3 mm, and the thickness of the thicker center strip is 2.9 mm, so the thickness increment is 1.6 mm. Assuming that the upper face temperature operating limit of the heater is 900°C, from this An analytical relationship can predict that for the 850°C case leaving the heater, the base band temperature may increase by about 8°C, and for the 750°C case, it may increase by about 22°C, with Figure 9 showing the curves crossing 900 in both cases. The base temperature rises when Go further downstream or consider higher operating temperatures to maximize heating efficiency.

To demonstrate the thermal management advantages over a conventional annealing furnace without additional local heating, Figure 10 is a numerical modeling plot comparing the thermal history of the glass ribbon in the pre-CCA section with and without additional local heaters. Figure 10 plots model data for glass temperature versus distance of the glass from VT. The heater configuration considered in the model is shown in Figure 8. Again, consider two initial conditions: the starting temperature of the glass ribbon is 850°C or 750°C. The solid line drawn is the temperature of the glass irradiated with a heater, and its surface temperature is maintained at 900°C. The dashed line represents the equipment setup, which includes Zircar plates, a low-expansion high-strength reinforced silica matrix composite used to retain heat, and the two modular sections (M2 and M3) of the annealing furnace as the primary thermal management tool. The bumps in the figure show the temperature rise of the glass ribbon for both sets of heaters, and their amplitudes are within the range predicted by the proportional relationship, that is, at 850°C, the temperatures of the two consecutive sets of heaters are approximately 5°C and 10°C. ℃, while at 750 ℃, the temperatures of both sets of heaters are around 15 ℃. As shown in the sub-table in Figure 10, at 850°C, when the glass ribbon reaches the CCA inlet, adding two sets of heaters increases the glass ribbon temperature by 8°C (from 684°C to 676°C), while at 750°C In this case, increase by 20℃ (from 637℃ to 617℃).

Figure 11 is modeled data that further compares the thermal gradient reduction from thick to thin between a pre-CCA heater and a standard equipment setup. The same conditions as described with respect to Figure 10 apply to Figure 11. Here, as shown in the sub-table in Figure 11, for the case of 850°C at the CCA inlet, adding two sets of heaters reduces the DT from thick to thin by about 30°C (141°C to 113°C) compared to the standard equipment Compared with the setting, it is about 40℃ lower (196℃ to 157℃). Self-analytical estimation and numerical modeling demonstrate that baseband heaters in the pre-CCA region can be implemented as an effective priority thermal management tool, helping to reduce thick-to-thin DT.

Figure 12 shows a part of an annealing furnace including a heat reflector (Zircar tunnel and radiation principle). In Figure 12, the glass ribbon moves from right to left after a viscous turn. Experiments show that the two Zircar plates on the annealing furnace modules M2 and M3 can increase the temperature of the glass strip at the CCA entrance by about 25°C. Use two or more Zircar panels or similar heat reflectors by placing the Zircar panels individually over the thinner sections and ensuring that the thicker sections remain radiant to a much cooler surface (<200°C to 300°C) or convection cooling The device can help reduce DT from thick to thin by 25°C or more.

Figures 13 and 14 show the use of "air rods" which use forced air to cool the thicker parts of the glass ribbon. Figure 13 shows a configuration with air bars above the glass ribbon, while Figure 14 shows a configuration with three air bars below the glass ribbon. By using convection, forced air allows concentrated heat removal from thicker parts of the glass ribbon without removing heat from thinner parts, thereby reducing thick-to-thin DT. Forced air may include steam injection as a means of humidification, which increases the heat capacity of the air and therefore increases the effectiveness of the air rods in reducing the temperature of thicker sections.

time condition DR FR 0 FR1 FR2 #weight ​ table settings Thermal settings 01h41m C10 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar plate, no cooling tool 02h57m C11 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 No Zircar board 03h49m C12 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar, with water core 05h08m C13 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar, A side with aerobar 05h42m C14 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar without any device in between 06h48m Q15 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar, B side with air cooling - medium - without Zircar plate 07h20m C16 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar, B side with air cooling - height - without Zircar plate 07h58m C17 1.04 shallow shallow shallow 28 There is 1 SiC rod on the M1 Zircar, B side with air cooling - height - Zircar plate Table 2

Table 2 lists the thermal setup conditions used for thermal testing, the results of which are shown in the graphs in Figures 15 and 16. Figures 15 and 16 show the maximum optical retardation and B-side part size warpage (PSW) of the thicker part. Both A-side and B-side cooling reduce the stress in DT and thicker parts from thick to thin by up to 25%. With A-side cooling, the warpage level remains unchanged compared to the baseline case of Zircar plates. On the other hand, the warpage of C15 and C16 increases in the B-side cooling cases. This is due to the fact that no Zircar plate is used above the glass ribbon, so the glass ribbon is cooler. Warpage is relatively low for condition C17, which has both B-side cooling and Zircar plates above the glass ribbon, but is still slightly higher than the baseline condition and the A-side cooling case.

The results are as expected, i.e., applying a slower cooling rate to the thicker portion before the leveling rollers FR1 and FR2 reduces stress without increasing warpage.

Figure 17 shows a side view of the glass ribbon traveling over the gas mast. The air rods provide support for the glass ribbon and the air flow allows air to escape between the air rods and the glass ribbon. The width of the air rod can be changed to provide more or less area for airflow to exit the air rod.

Figure 18 shows a top view of three air rods. The gray areas correspond to thicker parts of the glass ribbon, while the pink areas correspond to thinner parts. The gray areas can be cooled to lower the temperature and increase the rate of conductive heat transfer in the areas corresponding to the thicker sections. The pink area may be coated with a thermal barrier coating (e.g., zirconia) to increase the temperature of the thinner portion and reduce the rate of heat transfer between the glass ribbon and the air rod in the area corresponding to the thinner portion of the glass ribbon. Optionally, superheated steam (at ~900°C) can be used in the pink area instead of room temperature compressed air in conjunction with air rods to float the glass to increase the temperature and reduce heat transfer in the areas corresponding to the thinner parts of the glass ribbon Rate.

Figure 19 shows an embodiment in which the temperature difference between the thicker and thinner portions of the glass ribbon is reduced during the roll forming stage prior to viscosity turn. In this embodiment, forced air is directed from the nozzle to the forming roll at the portion across which the thicker portion of the glass ribbon crosses. The forced air directed to the thicker portion of the roll reduces the surface temperature of the roll and maximizes the amount of thermal energy removed from the thicker portion of the glass ribbon. Compressed air directed over thicker sections removes heat directly from the glass ribbon corresponding to the location where the air is concentrated. Forced air can be complemented with steam injection to increase heat capacity and the effectiveness of forced air in removing heat.

It should be understood that the foregoing description is merely illustrative of the invention. Various substitutions and modifications may be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to cover all such alternatives, modifications, and variations falling within the scope of the appended claims.

10:water core 20:Glass ribbon 28:Thick area 30:Bench 40: Cooling manifold 42: Self-water connection accessories 44:Water channel 50:Core

Figure 1A shows the water core cooling the thicker areas of the glass ribbon.

Figure 1B shows a manifold including a water core used to cool intermittent thicker areas of the glass ribbon.

Figure 2 shows the wicking wheel cooling the thicker part of the glass ribbon.

Figures 3 to 5 show atomization devices that cool thicker areas of the glass ribbon.

Figure 6 shows the stress birefringence measurement of a thicker section experimentally cooled with water spray.

Figure 7 shows a heater for preferentially heating portions of the glass ribbon.

Figure 8 shows the arrangement and relative spacing of the four heaters positioned relative to the glass ribbon.

Figure 9 is a graph showing the relationship between the heater surface temperature and the glass ribbon temperature of the ribbon passing through the heater.

Figure 10 plots model data for glass temperature versus distance of the glass from the viscous turn.

Figure 11 is a model data plot comparing the thick-to-thin thermal gradient reduction of a pre-CCA heater with a standard equipment setup.

Figure 12 shows a part of an annealing furnace including a heat reflector.

Figures 13 and 14 illustrate the use of air rods, which use forced air to cool thicker portions of the glass ribbon.

Figures 15 and 16 show the optical delay test data of the dimensional warpage of the thicker part and the B-side part.

Figure 17 shows a side view of the glass ribbon traveling over the gas mast.

Figure 18 shows a top view of three air rods.

Figure 19 illustrates an embodiment in which the temperature difference between the thicker and thinner portions of the glass ribbon is reduced during the roll forming stage prior to viscosity turn.

Domestic storage information (please note in order of storage institution, date and number) without Overseas storage information (please note in order of storage country, institution, date, and number) without

20:Glass ribbon

28:Thick area

40: Cooling manifold

42: Self-water connection accessories

44:Water channel

50:Core

Claims (20)

A glass ribbon processing apparatus for producing a glass ribbon having a first portion of a first thickness adjacent to a second portion of a second thickness, the apparatus including a water core contacting the third portion of the glass ribbon A portion to cool the first portion as the glass ribbon travels through the water core, wherein the first thickness is greater than the second thickness. The glass ribbon processing equipment of claim 1, wherein the first part is cooled at a first rate and the second part is cooled at a second rate, wherein the first rate is greater than the second rate. The glass ribbon processing equipment of claim 1, wherein the first part and the second part are oriented longitudinally along a length of the glass ribbon. The glass ribbon processing equipment of claim 1 further includes a heater located upstream of the water core. The glass ribbon processing equipment of claim 1, wherein the water core is a fabric strip. The glass ribbon processing equipment as claimed in claim 5, wherein one end of the water core is fixed above the glass ribbon. The glass ribbon processing equipment as described in claim 1, wherein the water core is circular and rotates around an axis. The glass ribbon processing equipment as claimed in claim 7, wherein when the glass ribbon travels in a horizontal direction, the water core is located below the glass ribbon. The glass ribbon processing equipment of claim 1, wherein the water core is attached to a substantially planar plate. A glass ribbon processing equipment for producing a glass ribbon with variable thickness, the apparatus includes an atomizer to spray a cooling liquid and/or cooling air on the glass as the glass ribbon travels through the atomizer on a thicker part of the belt to cool the thicker part. A glass ribbon processing apparatus for producing a glass ribbon of variable thickness, the apparatus includes a heater to heat a thinner portion of the glass ribbon as the glass ribbon travels past the heater. The glass ribbon processing equipment of claim 11, wherein the heater is two heaters positioned symmetrically across a width of the glass ribbon. The glass ribbon processing equipment of claim 11, wherein the heater is two heaters, one located above the glass ribbon and one located below the glass ribbon. A glass ribbon processing apparatus for producing a glass ribbon having a variable thickness includes an air rod to force air onto a portion of the glass ribbon as the glass ribbon travels past the air rod. The glass ribbon processing equipment as claimed in claim 14, wherein the air rod is located below the glass ribbon. The glass ribbon processing equipment of claim 15, wherein the air rod supports the glass ribbon. The glass ribbon processing apparatus of claim 14, wherein the air rod forces cooling air to reach a thicker portion of the glass ribbon. The glass ribbon processing apparatus of claim 14, wherein the air includes steam and is forced onto a thinner portion of the glass ribbon. A glass ribbon processing equipment for producing a glass ribbon including a first thickness and a second thickness, the equipment includes: a roller to support the glass ribbon as it travels past the roller; and A nozzle forcing cooling air onto a portion of the roll contacting the glass ribbon, wherein the first thickness is greater than the second thickness. The glass ribbon processing equipment of claim 19, wherein the portion of the roller in contact with the glass ribbon corresponds to the first thickness.