Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
  • C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B25/00—Annealing glass products
  • C03B25/04—Annealing glass products in a continuous way
  • C03B25/06—Annealing glass products in a continuous way with horizontal displacement of the glass products
  • C03B25/08—Annealing glass products in a continuous way with horizontal displacement of the glass products of glass sheets

Definitions

• the present invention relates generally to processes for making a glass substrate, and more particularly, to processes involving exposure of a glass substrate to an irradiation. Summary
• a pre-compacting secondary annealing process can be performed in an effort to lower the f ⁇ ctive temperature (Tf) originally set during formation of the glass substrate.
• Tf f ⁇ ctive temperature
• Glass compaction is also affected by the resistance of the glass to dimensional change during the thermal process. Such resistance is frequently represented by the glass viscosity during the thermal process, and is often represented by the strain point or annealing point, which are the temperature where the glass melt viscosity is equal to 10 14'7 and 10 13'18 Poise, respectively.
• the low temperature viscosity can be increased through adjustments of the glass composition, thereby increasing the relaxation time of the glass at a given temperature through the equation: ⁇ (T) ⁇ ⁇ (T) / G [0005]
• G is the shear modulus and scales the viscosity into a relaxation time. The increased relaxation time consequently causes a reduction in compaction through the following equation:
• Tf(t) is the f ⁇ ctive temperature of the glass as a function of time
• T is the heat treatment temperature
• ⁇ (T) is determined based on the viscosity curve for the glass.
• a reduction in f ⁇ ctive temperature during the thermal process typically results in a corresponding compaction of the glass substrate. Therefore, based on the inputs of the above equations, glass substrate compaction during a thermal cycle can be modeled by observing the change in f ⁇ ctive temperature.
• a process for making a glass substrate includes the step of providing a glass substrate including a structure with a fast relaxing species and a slow relaxing species.
• the glass substrate is provided at a bulk temperature (Tb) lower than a strain point (Tc) of the glass substrate.
• the process further includes the step of exposing the glass substrate to an irradiation capable of exciting part of the glass structure without increasing the bulk temperature (Tb) to above the strain point (Tc).
• the glass substrate is exposed to the irradiation in a manner that allows relaxation of the fast relaxing species without significant relaxation of the slow relaxing species.
• FIG. 1 is a schematic illustrative process for making a glass substrate including example aspects of the present invention
• FIG. 2A illustrates the hypothetical response of a fast and slow reacting species to a heating cycle without previously exposing the glass substrate to irradiation in accordance with aspects of the present invention
• FIG. 2B illustrates the hypothetical response of a fast and slow reacting species to a heating cycle performed after exposing the glass substrate to irradiation in accordance with aspects of the present invention
• FIG. 3 is a representation of the glass substrate being heated after being exposed to irradiation in accordance with the present invention
• FIG. 4 is a graph of experimental results representing volumetric change of two glass substrates over a heating cycle, wherein only one of the glass substrates was previously exposed to irradiation in accordance with the present invention.
• the process of the present invention for treating glass materials can be applied to various glass materials in various forms, such as glass sheets, glass plates, glass rods, and the like, formed by various methods, such as rolling, pressing, fusion draw, slot draw, float, and the like.
• the present invention is particularly useful, however, for glass materials formed in a step where a high cooling rate is imposed, such as at 5°C/second or higher.
• the glass substrate can consist essentially of a glass material having an anneal point of at least 640 0 C although glass substrate can consist essentially of a glass material with other anneal points and/or comprise various glass material components having a wide range of anneal points that are blended together.
• the glass material may have an anneal point of at least 720 0 C.
• the glass material can have an anneal point of at least 770 0 C.
• a glass sheet suitable for semiconductor film deposition on a surface thereof may be further subject to a step of semiconductor deposition upon completion of the irradiation treatment according to the present invention. Example processes can produce glass substrates for various applications.
• a method of making a liquid crystal display can incorporate a glass substrate made with processes in accordance with aspects of the present invention.
• FIG. 1 a schematic illustration of a process includes example aspects of the present invention. For illustration purposes, these example aspects are demonstrated in a single continuous production line. It will be appreciated that one or more of the illustrated steps may be conducted separately or omitted altogether. For example, each of the illustrated process steps may be carried out at a different location and/or at a different time. In one example, a series of steps are performed at one location. Then one or more subsequent steps can be performed at a different location. Furthermore, the glass substrate may be subject to additional steps not illustrated in the example schematic illustration shown in FIG. 1. [0018] As shown in FIG.
• the example process can provide with glass material processed to form an initial glass substrate.
• the glass material can be formed into a glass substrate 102 using a fusion draw process 100.
• the glass substrate 102 can be formed using a float process, a down-draw process, a rolling process, and/or other glass substrate forming processes.
• the glass substrate is formed as a glass substrate sheet although other substrate configurations may be provided in further examples.
• the glass substrate can be optionally cooled at various predetermined rates after being formed by the fusion draw process 100 or other forming techniques.
• the glass substrate can be subjected to a cooling process at an average cooling rate of at least 5 °C/s from the softening temperature (Ts) of the glass substrate to the strain point (Tc) of the glass substrate.
• the predetermined cooling rate if provided, can be achieved in various ways.
• the surrounding environment can be provided with conditions to provide a favorable cooling rate.
• the fusion draw process 100 can be carried out in an atmosphere with a predetermined composition, temperature and/or circulation to control the cooling rate of the glass substrate.
• an optional cooling mechanism 300 such as the illustrated fan, or a device controlling the circulation of cooling air around the glass surface, can be provided to facilitate cooling of the glass substrate at the predetermined rate. If provided, the cooling mechanism 300 can comprise the illustrated fan although other cooling devices can be provided in further examples.
• the glass substrate 102 can be drawn in a downward direction 104a until a sufficient length of glass substrate is achieved. Once the desired length is reached, a downstream portion 102b of the glass substrate can be separated from an upstream portion 102a of the glass substrate. For instance, as shown, a laser device 200 can laterally score the glass substrate with a laser beam 202 to aid the split and release of the downstream portion 102b of the glass substrate. In further examples, the downstream portion 102b can be cut by grinding, fracturing, scoring or other separation techniques. In further examples, the glass substrate 102 may remain in tact during various further procedures set forth herein.
• the glass substrate can continue from the fusion draw process or other glass forming process such as the float process through the subsequently described cooling procedure, irradiating zone 500, treatment zone 600 and/or heating zone 700 before the downstream portion 102b of the glass substrate is separated from the upstream portion 102a of the glass substrate. Therefore, example processes can feed the glass substrate 102 from the glass forming process (e.g., fusion draw process 100) in a continuous manner on a production line before cutting the downstream portion 102b from the upstream portion 102a of the glass substrate 102.
• the cooling mechanism 300 can be provided to cool the upstream portion 102a of the glass substrate at the predetermined cooling rate.
• the cooling mechanism can be provided to cool the downstream portion 102b at the predetermined cooling rate before or after separating the downstream portion 102b of the glass substrate from the upstream portion 102a of the glass substrate.
• An optional glass substrate handling apparatus 400 can be provided to carry the glass substrate through various optional process zones.
• the handling apparatus 400 can include an optional orienting device 402 with an air bearing 404 that may reorient the glass substrate and/or place the glass substrate on a conveyor mechanism 406.
• the glass substrate 102c for example, may be positioned on the conveyor mechanism 406 prior to entering an irradiating zone 500.
• the glass substrate 102c includes a structure that has a relaxation characteristic "frozen" into the substrate based on the glass substrate formation process.
• a relaxation characteristic "frozen" into the substrate based on the glass substrate formation process.
• the fast relaxation species can be considered to include a single species group or may include multiple species groups that behave together as the fast relaxation species.
• the slow relaxation species can be considered to include a single species group or may include multiple species groups that behave together as the slow relaxation species.
• FIG. 2A represents application of a heating cycle 114, such as a rapid thermal anneal (RTA), to the glass substrate 102c that has not yet entered the irradiating zone 500 discussed more fully below.
• the y-axis represents temperature while the x-axis represents time.
• the heating cycle 114 includes a heating segment 114a representing an increase in the temperature of the glass substrate.
• the heating cycle 114 further includes a hold segment 114b representing a period of time where the glass substrate is held at a maximum heated temperature.
• FIG. 2A also demonstrates a hypothetical fictive temperature profile 110 of the slow relaxing species before, during and after conducting the heating cycle 114.
• the slow relaxing species is shown to include an initial fictive temperature represented by the horizontal segment 110a.
• the fictive temperature of the slow relaxing species is reduced over time as represented by the downwardly sloped segment 110b.
• the cooling segment 114c the fictive temperature of the slow relaxing species is "frozen in" at the final fictive temperature represented by the horizontal segment 110c.
• FIG. 2A still further demonstrates a hypothetical fictive temperature profile 112 of the fast relaxing species before, during and after conducting the heating cycle 114.
• the fast relaxing species is shown to include an initial fictive temperature represented by the horizontal segment 112a.
• the fictive temperature of the fast relaxing species is reduced over time as represented by the downwardly sloped segment 112b.
• the fictive temperature of the fast relaxing species eventually reaches equilibrium with the treatment temperature and follows the bulk temperature of the glass substrate during a later portion of the heating segment 114a, the hold segment 114b and a beginning portion of the cooling segment 114c.
• the fictive temperature of the fast relaxing species is eventually "frozen” at the final fictive temperature represented by the horizontal segment 112d. Comparing horizontal segments 112a and 112d, the final fictive temperature of the fast relaxing species is lower than the initial fictive temperature of the fast relaxing species.
• the arrow 113a represents a decrease in fictive temperature from the initial fictive temperature to the final fictive temperature of the fast relaxing species.
• both the fast relaxing species and the slow relaxing species are believed to contribute to compaction of the glass substrate during the heating cycle 114.
• FIG. 2B is similar to FIG. 2A but represents application of the heating cycle 114 to the glass substrate 102d after the step of irradiating the glass substrate 102d in the irradiating zone 500 as discussed more fully below. As shown in FIG.
• the hypothetical fictive temperature profile 110 of the slow relaxing species remains substantially the same as the profile 110 illustrated in FIG. 2A.
• exposing the glass substrate 102d to the irradiation can be considered to substantially impact the hypothetical fictive temperature profile 112 of the fast relaxation species.
• the fast relaxing species is shown to include an initial fictive temperature represented by the horizontal segment 112e that is substantially lower than the initial fictive temperature represented by the horizontal segment 112a shown in FIG. 2A.
• the fictive temperature of the fast relaxing species remains at the initial fictive temperature but, as represented by segment 112f, eventually begins to match the temperature of the glass substrate during a later portion of the heating segment 114a, the hold segment 114b and a beginning portion of the cooling segment 114c.
• the fictive temperature of the fast relaxing species is eventually "frozen" into the glass substrate at the final fictive temperature represented by the horizontal segment 112g (the same as 112d since the final fictive temperature of the fast relaxing species is determined by the cooling rate 114c of the heating cycle).
• the final fictive temperature of the fast relaxing species is higher than the initial fictive temperature of the fast relaxing species.
• the arrow 113b represents an increase in fictive temperature from the initial fictive temperature to the final fictive temperature of the fast relaxing species.
• a decrease in fictive temperature tends to result in compaction of the glass substrate.
• an increase in fictive temperature tends to result in expansion of the glass substrate.
• exposing the glass substrate to an irradiation is believed to allow the relaxed fast relaxing species expand and the slow relaxing species contract during the heating cycle 114 thereby partially cancelling each other out and reducing the net dimensional change of the substrate.
• the glass substrate 102d can be exposed to the irradiation while the bulk temperature (Tb) of the glass substrate is lower than the strain point (Tc) of the glass substrate.
• the bulk temperature (Tb) of the glass substrate can be measured, for example, by an infrared (IR) temperature reading, contact thermocouple or other measuring configuration.
• IR infrared
• Tb is designed to refer to the overall temperature of the glass substrate rather than specific points of the glass substrate that may be higher or lower than (Tb).
• Example aspects of the present invention can provide the glass substrate 102c with a structure including a fast relaxing species and a slow relaxing species.
• the glass substrate 102c is provided at a bulk temperature (Tb) lower than the strain point (Tc) of the glass substrate 102c.
• the optional conveyor mechanism 406 can then transport the glass substrate 102c along direction 104c to an irradiating zone 500.
• the irradiating zone 500 can be provided with an optional housing 502 and an irradiation source 504 to deliver irradiation 506 to the glass substrate 102d.
• the glass substrate 102d While in the irradiating zone 500, the glass substrate 102d is exposed to an irradiation capable of exciting part of the glass structure without increasing the bulk temperature (Tb) of the glass substrate 102d above the strain point (Tc) of the glass substrate 102d.
• the glass substrate 102d is exposed to the irradiation 506 in a manner that allows relaxation of the fast relaxing species without significant relaxation of the slow relaxing species.
• the irradiation source 504 can provide various alternative types of irradiation.
• the irradiation 506 can comprise one or more of infrared irradiation, microwave irradiation, ultraviolet irradiation and/or various combinations of these or other types of irradiation.
• the irradiation 506 can be pulsed although non-pulsed (e.g., continuous) irradiation can be provided in further examples.
• the irradiation source 504 may be a laser device although other irradiation devices may be used in further examples. If provided as a laser device, the irradiation 506 can be delivered as one or more pulsed or non-pulsed laser beams.
• a 248 nm ultraviolet pulsed laser may be used in accordance with aspects of the present invention.
• the glass substrate 102d can be exposed to the irradiation 506 for various time periods. In one example, any part of the glass substrate 102d can be exposed to the irradiation 506 for a period of at most 4 hours. For instance, any part of the glass substrate 102d can be exposed to the irradiation 506 for a period within the range of from about 4 to about 18 hours exposure time may be above or below this range in further examples.
• the glass substrate 102d can be exposed to pulsed or non-pulsed irradiation over a time period with a single time interval although a time period may include a plurality of intermittent time intervals.
• the bulk temperature (Tb) of the glass substrate 102d can be maintained below a certain level while being exposed to the irradiation 506.
• the bulk temperature (Tb) of the glass substrate 102d can be increased by less than 200 0 C during the step of exposing the glass substrate 102d to the irradiation 506, such as less than 150 0 C, such as less than 100 0 C, such as less than 50 0 C, for instance less than 30 0 C.
• the bulk temperature (Tb) can be less than (Tc) - 200 0 C, wherein (Tc) is the strain point of the glass substrate.
• the bulk temperature (Tb) can be less than (Tc) - 300 0 C, such as less than (Tc) -400 0 C, for example less than (Tc) - 500 0 C.
• the bulk temperature (Tb) of the glass substrate 102d can be less than 300 0 C, such as less than 250 0 C, such as less than 200 0 C, such as less than 150 0 C, for instance less than 100 0 C. It will therefore be appreciated that the step of exposing the glass substrate 102d to the irradiation 506 can be conducted at a significantly lower temperature than the typical secondary thermal annealing process, thereby reducing the risk of undesirable changes to the glass substrate (such as deformation).
• the conveyor mechanism 406 can then transport the glass substrate 102d along direction 104d after sufficient exposure to the irradiation 506.
• the glass substrate 102d can be moved to a treatment zone 600 wherein a glass substrate 102e is provided with one or more layers 103 of amorphous or polycrystalline silicon.
• an apparatus 602 can apply the layer 103 as the glass substrate 102e travels along direction 104e.
• the amorphous or polycrystalline silicon can be applied by various other techniques and can be applied to one or both sides of the glass substrate 102e.
• the glass substrate 102d passes from the irradiating zone to the treatment zone 600 without subjecting the glass substrate 102d to a secondary thermal annealing process.
• the step of exposing the glass substrate to irradiation may eliminate the need for a secondary annealing process or may allow the use of a reduced intensity secondary annealing process.
• the glass substrate 102f may be further processed in a heating zone 700.
• the heating zone 700 may include a resistance heater 702 configured to raise the bulk temperature (Tb) to greater than 300 0 C such that the relaxed fast relaxing species expands and the slow relaxing species contracts.
• the heating procedure can be carried out during or prior to fabricating an (LCD) display. For example, as shown, the heating procedure can be performed on the production line shown in FIG. 1.
• the glass substrate may pass through the irradiating zone 500 and the treatment zone 600. The glass substrate 102e can then be transported to another location for conducting the heating procedure represented by the heating zone 700.
• contraction of the slow relaxing species is substantially equal to expansion of the fast relaxing species during the step of heating the glass substrate 102f in the heating zone 700.
• compaction and/or expansion of the glass substrate 102f can be substantially avoided.
• contraction of the slow relaxing species is only partially compensated by expansion of the fast relaxing species.
• the glass substrate 102f can experience compaction. However, such compaction may be less than compaction that may otherwise be experienced without exposing the glass substrate to irradiation in the irradiating zone.
• expansion of the fast relaxing species is greater than the contraction of the slow relaxing species. In such examples, the glass substrate 102f can experience expansion.
• the extent of irradiation in the irradiating zone 500 and/or the extent of heating in the heating zone 700 can be used to control the overall dimensional change of the glass substrate 102f when heating the glass substrate 102f above 300 0 C.
• the glass substrate can be irradiated in a manner to reduce, such as avoid compaction of the glass substrate 102f. As such, undesirable dimensional changes can be reduced, and potentially avoided.
• FIG. 3 is a representation of the glass substrate 102f being heated in the heating zone 700 at a hypothetical temperature (such as 450 0 C) after being exposed to irradiation in accordance with the present invention.
• the y-axis represents volumetric change while the x-axis represents time.
• the expansion curve 154 represents the expansion of the fast relaxing species while the contraction curve 156 represents the compaction of the slow relaxing species.
• the dimensional curve 150 represents the overall dimensional change of the glass substrate 102f in the heating zone based on the expansion of the relaxed fast relaxing species and compaction of the slow relaxing species. As shown, initial expansion of the fast relaxing species overcompensates for initial compaction of the slow relaxing species. Therefore, the glass substrate 102f initially expands during heating in the heating zone 700 as represented by upwardly sloped segment 150a of the dimensional curve 150.
• FIG. 4 is a graph representing actual test data comparing the dimensional curve 401, with a dimensional curve 403 of the glass substrate 102c that has not been exposed to irradiation in accordance with the present invention.
• the test data represents dimensional changes occurring over time when the glass substrates 102c and 102f are held in the heating zone 700 at a temperature of 450 0 C.
• the y-axis represents dimensional change of the glass substrates in parts per million (ppm) while the x-axis represents time in minutes.
• the dimensional curve 403 demonstrates continually increasing compaction between time zero and 300 minutes.
• the dimensional curve 401 representing the glass substrate 102f confirms initial expansion of the glass substrate 102f and then compaction of the glass substrate 102f. As shown, a net zero change in dimension occurs at approximately 45 minutes to 60 minutes (point 405) of heating within heating zone 700 at 450 0 C.
• the zones 500, 600 and 700 may be located in the same facility, in close proximity to each other, or with large distance between each other, or in differing facilities.
• the irradiation treatment step, the thin film application step and the post thermal treatment step can be carried out in the same or different location, by the same or different entities.
• non-limiting aspects and/or embodiments of the present disclosure include: [0042] Cl .
• a process for making a glass substrate comprising the steps of:
• step (b) exposing the glass substrate to an irradiation capable of exciting part of the glass structure without increasing Tb above Tc, wherein the glass substrate is exposed to the irradiation in a manner that allows relaxation of the fast relaxing species without significant relaxation of the slow relaxing species.
• Tb is increased by less than 200 0 C.
• C5. The process of any one of Cl to C4, wherein the glass substrate consists essentially of a glass material having an anneal point of at least 640 0 C.
• C6. The process of any one of Cl to C5, wherein the irradiation is selected from the group consisting of infrared irradiation, microwave irradiation, and ultraviolet irradiation.
• C7 The process of any one of Cl to C6, wherein in step (b), the irradiation is pulsed.
• C8 The process of any one of Cl to C7, wherein in step (b), any part of the glass substrate is exposed to the irradiation for a period of at most 4 hours.
• C9. The process of any one of Cl to C8, wherein before step (a), the glass substrate is subjected to a cooling process at an average cooling rate of at least 5 °C/s from Ts to Tc, where Ts is the softening temperature of the glass substrate.
• ClO A process for making an LCD glass substrate using the process of any one of Cl to C9.
• C12 The process of Cl 1, wherein after step (b) and prior to step (c), the glass substrate is not subjected to a secondary thermal annealing step.
• C 13 The process of any one of Cl to C 12, further comprising, after relaxation of the fast relaxing species, raising Tb to greater than 300 0 C such that the relaxed fast relaxing species expands and the slow relaxing species contracts.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Toxicology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Health & Medical Sciences (AREA)
• Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
• Dispersion Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Surface Treatment Of Glass (AREA)
• Formation Of Insulating Films (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (2)

Family

ID=43223370

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (1)

Citations (3)

Family Cites Families (9)

• 2010
  • 2010-05-28 TW TW099117271A patent/TWI474989B/zh not_active IP Right Cessation
  • 2010-05-28 CN CN201080023543.5A patent/CN102448899B/zh not_active Expired - Fee Related
  • 2010-05-28 WO PCT/US2010/036529 patent/WO2010138793A2/en active Application Filing
  • 2010-05-28 KR KR1020117031543A patent/KR101704841B1/ko active IP Right Grant
  • 2010-05-28 JP JP2012513281A patent/JP5738282B2/ja not_active Expired - Fee Related

Patent Citations (3)

Also Published As

Similar Documents

Legal Events