TWI464124B - Roll-to-roll glass material attributes and fingerprint - Google Patents

Description

Roller to roller glass material properties and characteristics

The present invention is generally directed to glass flakes, and more particularly to sintered glass flakes, such as yttria glass flakes made using glass dust deposition, and a sintering process.

The glass sheet material can be formed using a variety of different methods. For example, in a floating glass process, a solid glass piece is made by floating molten glass on a hearth of molten metal. This process can be used to form a glass sheet having a uniform thickness and an extremely flat surface. However, this floating glass process inevitably involves direct contact between the glass melt and the molten metal, which may cause undesirable contamination at the interface and inferior quality to the original surface. In order to produce high quality floating glass sheets with original surface properties on both major surfaces, the floating glass is typically subjected to a surface polishing step, which adds additional expense. In addition, it is believed that the floating process has not been used to make ultra-thin, rollable glass sheets.

Another method for forming a glass sheet material is a melt drawing process. In this process, the molten glass is fed into a groove called an "isopipe" such that the glass overflows until the molten glass flows evenly across the sides. The molten glass then meets at the bottom of the trench, or fuses, where it is drawn down to form a continuous flat glass sheet. Since the two major surfaces of the glass sheet do not directly contact any of the support materials during the forming process, high surface quality can be achieved in both major surfaces.

However, due to the dynamic nature of the melt drawing process, the amount of glass composition suitable for melt drawing is limited by those having the necessary properties in the molten phase (ie, such as liquid viscosity, strain point, etc.) . In addition, although a relatively thin glass piece can be produced by this melt drawing, the process cannot be used to form an ultra-thin, rollable, highly oxidized bismuth glass sheet. Finally, the equipment used in the melt drawing process is expensive.

In addition to the limitations of ultra-thin glass sheet materials, both the floating and melt drawing processes are impractical for high yttrium oxide glass sheets due to the high softening point of yttrium oxide (~1600 ° C). method. In contrast, yttria glass substrates are typically produced by cutting, grinding and polishing a cerium oxide ingot produced in a batch flame hydrolysis furnace. This batch approach is extremely costly and wasteful. Indeed, the necessary scribing and polishing processes required to produce a uniform, meager, elastic yttria glass sheet by flame hydrolysis can make the process prohibitively expensive. Using known methods, the applicant is convinced that it is currently not feasible to form and polish both sides of a high yttria glass sheet having a thickness of less than 150 microns.

In view of the foregoing disclosure, the economical, uniform, ultra-thin, and elastic, high-volume, high-volume, high-yield glass sheets are desirable. High yttrium oxide glass flakes may contain one or more laminates, components or phases. These glass sheets can be used as, for example, a light mask substrate, an LCD image mask substrate, and the like. The high yttria glass flakes have two major opposing surfaces, having an average thickness of 150 microns or less, and having an average surface roughness above at least one of the two major surfaces of 1 nm or less. In a specific embodiment, the average surface roughness is 1 nm or less above both of the two major surfaces. An exemplary high cerium oxide glass sheet is measured at least 2.5 x 2.5 cm ² . For example, the glass sheet may have a width ranging from about 2.5 cm to 2 m, and the glass sheet may have a length ranging from about 2.5 cm to 10 m or more. Indeed, the length of the glass sheet is substantially limited only by the deposition time and can extend over 10 m to 10 km or more. The glass sheet is formed using a roller-to-roller glass dust deposition and sintering process. In a further embodiment, the glass sheet contains a plurality of imaginary visible slats. The slats are caused by regional thickness variations and are only visible when the major surface of the glass sheet is viewed at an angle that is significantly shifted away from the incident normal.

Other features and advantages of the invention will be apparent from the description and appended claims.

The prior general description and the following detailed description are to be considered as illustrative and illustrative, and The accompanying drawings are included to provide a further understanding of the invention and are incorporated herein as part of the description. The drawings illustrate various embodiments of the invention, and are in the

The high yttria glass flakes have an average thickness of less than 150 microns and an average surface roughness of less than 1 nm above or below one of their two major surfaces. The transverse dimension of the glass sheet can range from about 2.5 cm to 2 m wide and from about 2.5 cm to 3 m long or longer. Figure 1 is a schematic view of an apparatus for forming an ultra-thin high yttria glass sheet. The apparatus 100 includes a dust supply device 110, a dust receiving device 120, a dust sheet guiding device 130, and a dust sintering device 140. Referring now to the apparatus of Figure 1, a method for forming a glass sheet is disclosed.

The glass dust particles formed by the dust supply device 110 are deposited on the deposition surface 122 of the dust receiving device 120. The dust receiving device 120 can advantageously be in the form of a rotatable drum or strip and thus can contain a continuous deposition surface 122. The deposited dust particles 150 form a dust layer 152 on the deposition surface 122. Once formed, the dust layer 152 can be released from the deposition surface 122 to become a self-standing, continuous dust sheet 154. In a preferred embodiment, the action of releasing the dust layer 152 from the deposition surface 122 can be performed without physical intervention, and the coefficient of thermal expansion between the dust layer and the deposition surface can be mismatched, for example, due to thermal mismatch. / or gravity effect. After the dust sheet 154 is released from the dust receiving device 120, the dust sheet guiding device 130 can guide the dust sheet 154 to move through the dust sintering device 140, and the device can sinter and fix the dust sheet 154 to form Ultra-thin glass piece 156.

The process of forming an ultra-thin glass sheet includes providing a plurality of glass dust particles; depositing the glass dust particles on a deposition surface of the dust receiving device to form a dust layer; releasing the dust layer from the dust receiving surface to form a dust sheet And sintering the dust sheet to form a glass sheet. Further details of these processes and equipment will be described in further detail below.

However, various devices can be used to form glass dust particles. By way of example, the dust supply device 110 can include one or more flame hydrolysis burners, such as external vapor deposition (OVD), vapor phase axial deposition (VAD). ) and users in the planar deposition process. Suitable burner configurations are disclosed in U.S. Patent Nos. 6,660,883, 5,922,100, 6, 678, 676, issued to the Official Utility of

The dust supply device 110 may contain a single burner or a plurality of burners. An exemplary burner can have an output surface of length l and width w. The output surface contains N longitudinal gas nozzles, wherein N can range from 1 to 20 or above. In one embodiment, each nozzle contains a 0.076 cm diameter hole. The length l of the output surface may range from about 2.5 to 30.5 cm or more, and the width w may range from about 0.1 to 7.5 cm. Multiple burner configurations can be configured as a burner array, as desired, which can produce substantially continuous flow of dust particles over the width of the array.

The array of burners, for example, may contain a plurality of individual burners (i.e., placed in an end-to-end manner) and configured to form and deposit a layer of glass dust that is uniform in time and space. Therefore, the dust providing device can be utilized to form a chemical composition having substantially uniformity and a dust layer having a substantially uniform thickness. By "homogeneous composition" and "uniform thickness" is meant that the composition and thickness variation over a given area is less than or equal to 20% of the average composition or thickness. In some embodiments, one or both of the composition or thickness variations of the dust sheet may be less than or equal to 10% of the individual flat uniformity values of the dust sheet.

The exemplary burner contains nine longitudinal gas nozzles. According to a specific embodiment, the midline wales (i.e., wales 5) provide a cerium oxide gas precursor/carrier gas mixture during use. Immediately adjacent to the wales (i.e., wales 4 and 6) oxygen is provided to stoichiometrically control the cerium oxide gas precursor. The next two wales on either side of the centerline (ie, wales 2, 3, 7, and 8) provide additional oxygen, and the flow rate can be used to control stoichiometry and dust density while providing a pilot flame Oxidizer. The outermost nozzle wales (i.e., wales 1 and 9) may provide a pilot flame mixture such as CH ₄ /O ₂ or H ₂ /O ₂ . The exemplary gas flow range for a 9-row linear burner can be as shown in Table 1.

The dust providing means may remain fixed during the formation and deposition of dust particles; or the dust providing means may move (i.e., oscillate) relative to the deposition surface. The distance from the burner to the deposition surface can range from about 20 mm to 100 mm (eg, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100mm).

The operation of the dust providing device typically involves a chemical reaction between the precursor chemicals (i.e., gas compounds) to form glass dust particles. These chemical reactions can be selectively further assisted by a complementary source of energy, such as a plasma or supplemental heating device.

For example, a ruthenium-containing precursor compound may be utilized to form a dust sheet containing cerium oxide dust particles and sintered to form a yttria glass sheet. An exemplary ruthenium-containing precursor is octamethylcyclotetraoxane (OMCTS). OMCTS may be in conjunction with H _2, O _2, CH ₄ or other fuel is introduced into the burner or burner array, this person will be hydrolyzed and oxidized to produce a silicon oxide dust particles. The process for forming a glass sheet generally includes the formation of a high-oxide glass sheet, and the processes and equipment can be used to form other glass sheet materials.

The dust particles may consist essentially of a single phase (ie, a single oxide), as in the case of undoped, high purity yttria glass, as produced or as deposited. . Alternatively, the dust particles may contain two or more components or two or more phases, as in the case of a doped yttria glass. For example, a multi-phase high cerium oxide glass sheet can be produced by incorporating a titanium oxide precursor or a phosphorus oxide precursor into the OMCTS gas stream. Exemplary titanium and phosphorus oxide precursors comprise various soluble metal salts with metal alkoxides such as phosphorus and titanium (IV) isopropanol halides.

In the example of a flame hydrolysis burner, doping can be performed on-site during flame hydrolysis by introducing a dopant precursor into the flame. In a further example, such as a plasma-heated dust sprayer, the dust particles sprayed from the sprayer may be pre-doped; or the other sprayed dust particles may be exposed to dopants. The plasma atmosphere allows the dust particles to be incorporated into the plasma. In still further examples, the dopant can be incorporated into the dust sheet prior to or during the sintering of the dust sheet. Exemplary dopants include elements of the IA, IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VB groups of the Periodic Table of the Elements, as well as rare earths.

The dust particles may have a substantially homogeneous composition, size and/or shape. Alternatively, one or more of the components, size and shape of the dust particles may vary. For example, dust particles of a main glass component may be provided by the first dust supply device, and dust particles of a dopant component may be provided by the second dust supply device. In some embodiments, during the action of forming and depositing the dust particles, the dust particles can be mixed and/or attached to the other to form composite particles. It is also possible that the dust particles are substantially prevented from adhering to one another prior to deposition on the deposition surface, or at the same time to facilitate the formation of mixed particles.

Still referring to FIG. 1, the deposition surface 122 includes a peripheral portion of the dust receiving device 120 and may be formed of a heat resistant material. In one embodiment, the deposition surface 122 is formed from a material that is chemically and thermally compatible with the dust particles 150 and the deposited dust layer 152, and the dust layer can be easily removed therefrom. The exemplary dust receiving device 120 contains a heat resistant material (i.e., such as yttria, tantalum carbide, graphite, zirconia, etc.) and is plated or coated on a core material such as a steel, aluminum or metal alloy. The dust receiving means may further comprise unit members consisting essentially of a suitable heat resistant material such as quartz.

The dust receiving device 120, in particular the deposition surface 122, can be configured in a variety of different manners and possesses a variety of shapes and/or sizes. For example, the width of the deposition surface can range from about 2 cm to 2 m, but can also be smaller or larger. The cross-sectional shape of the dust receiving device 120 may be circular, oval, elliptical, triangular, square, hexagonal, etc., and the corresponding cross-sectional dimensions (i.e., diameter or length) of the dust receiving device 120 may also vary. For example, a dust receiving device having a circular cross section may have a diameter ranging from about 2 cm to 50 cm. The exemplary dust receiving device 120 contains a quartz cylinder having an inner diameter of 250 mm, an inner diameter of 260 mm, and a deposition surface of 24 cm width.

In the example of a circular or oval cross section, the deposition surface 122 may contain a closed, continuous surface, while in the case of an elliptical, triangular or hexagonal cross section, the deposition surface may contain a segmental surface. By appropriately selecting the size and size of the dust receiving device 120, a continuous or semi-continuous dust sheet can be formed.

The deposition surface 122 can comprise a regular or irregular pattern in the form of raised or recessed protrusions over a range of length ratios. The pattern can range from one or more discrete faces to a general roughening of the surface. Thus, the deposited dust layer can conform to the patterning within the deposition surface. The pattern formed in the surface of the dust may remain in the surface of the deposited dust sheet when separated from the deposition surface, and thus may be retained in the sintered surface of the obtained glass sheet to obtain a embossed glass sheet. In the foregoing variation of the embossing process derived from the deposition surface, one or both of the deposited surface and the free surface of the dust sheet may be patterned prior to sintering after removal from the deposition surface. For example, the applicant of the present invention has already patterned the surface of the dust sheet by fingerprint. When the dust sheet is sintered, the fingerprint pattern is retained in the obtained glass sheet.

In some embodiments, during the action of depositing the dust particles 150, the dust receiving device 120 is rotated to form a dust layer 152 thereon. This rotation can be unidirectional, such as clockwise or counterclockwise. The direction of rotation according to a particular embodiment may be as indicated by arrow A in FIG. The dust receiving device 120 can selectively oscillate during the dust deposition process, that is, the direction of rotation can be intermittently changed. The linear velocity of the deposition surface 122 of the dust receiving device 120 can range from 0.1 mm/sec to 10 mm/sec (eg, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, or 10 mm/sec). When increased, it is believed that the linear velocity of the deposition surface can be increased to 1 m/sec or faster.

Dust particles 150 are deposited only on a portion of the deposition surface 122 while the deposited dust layer 152 can be removed to form a free standing, continuous or semi-continuous, length L dust sheet 154. That is, as shown in FIG. 1, the deposited layer 152 (the dust sheet 154 in the name) has a width W.

In some embodiments, the dust sheet can be continuously formed or continuously removed on/from the deposition surface. During the formation of the dust layer, the dust particles are bonded to each other to some extent and to the deposition surface. The higher the average temperature of the dust particles when deposited, the more likely they are to bond to each other while forming dense and mechanically strong dust flakes. However, the higher the deposition temperature, the higher the bonding between the dust particles and the deposition surface, which will interfere with the release of the dust particles. To achieve a substantially uniform temperature across the deposition surface, the dust receiving device can be heated or cooled from its interior, exterior or both.

The bonding between the dust particles and the deposition surface can be controlled by controlling the temperature gradient between the location at which the dust particles are deposited and the location at which the dust layer is released to form a dust sheet. For example, if the dust layer and the deposition surface have sufficiently different coefficients of thermal expansion (CTE), the release can be spontaneously achieved due to the stress caused by the temperature gradient. In some embodiments, the deposited dust layer can be removed from the deposition surface more easily by forming a dust layer having a width W that is less than the width of the deposition surface 122.

During the action of separating the dust layer from the deposition surface, the direction of movement of the separated dust sheet may be substantially tangential to the release point on the deposition surface. By "substantially tangential" is meant that the direction of movement of the dust sheet relative to the release point on the deposition surface does not deviate by more than 10 degrees (ie, less than 10) from the tangential direction of the deposition surface at the release point. 5, 2 or 1 degree). Maintaining a substantially tangential release angle reduces the stress applied to the dust sheet at the point of release.

For a dust receiving device having a circular or oval cross section, the curvature of the deposition surface is a function of the diameter of the cross section of the dust receiving device. As the diameter becomes larger, the radius of curvature increases, and the stress in the deposited dust decreases as the shape of the deposited dust sheet approaches a flat planar sheet.

In various embodiments, the dust sheet has sufficient mechanical integrity to support its own quality (i.e., during removal from the deposition surface, during handling and sintering) without breaking. The process variables that may affect the physical and mechanical properties of the dust sheet include the thickness and density of the dust sheet, the curvature of the deposition surface, and the temperature of the dust sheet during formation, but are not limited thereto.

The dust sheet contains two major surfaces, only one of which will contact the deposition surface during the formation of the dust layer. Thus, the two major surfaces of the dust sheet and the sintered glass sheet from which it is derived can be characterized and distinguished as a "deposited surface" and an opposite "free surface".

In an example of a dust sheet containing at least 90 mole % cerium oxide, the dust sheet may have an average dust density ranging from about 0.3 to 1.5 g/cm ³ , for example from about 0.4 to 0.7 g/cm ³ , or from It is about 0.8 to 1.25 g/cm ³ , and the dust sheet may have an average thickness ranging from 10 to 600 μm, for example, from 20 to 200 μm, 50 to 100 μm or from 300 to 500 μm.

In some embodiments, particularly those involving continuous dust sheets and/or sintered glass sheets, the dust sheet guiding device 130 may be used to assist the dust sheet to continuously move away from the sheet after it is released. Deposit the surface. The dust sheet guiding device 130 can directly contact at least a portion of the dust sheet 154 to assist the movement of the dust sheet and provide mechanical support thereto.

In order to maintain the high surface quality of the dust sheet, the dust sheet guiding device 130 may only contact a part of the dust sheet 154 (i.e., as a part of the edge). In some embodiments, the dust sheet guiding device includes a pair of jaw rollers that grip the edges of the dust sheet and guide the dust sheet through the dust sheet sintering device.

With the dust sheet guiding device, the continuous dust sheet can be fed into the sintering/annealing zone of the dust sintering device 140, wherein at least a portion of the dust sheet is heated to a temperature and maintained for a period of time sufficient to heat the film. The time to locally convert to densified glass. For example, a dust sheet having high purity cerium oxide can be sintered at a temperature range, i.e., from about 1000 ° C to 1900 ° C, such as from about 1400 ° C to 1600 ° C, thereby forming an ultrathin yttria glass sheet 156. The sintering temperature and the sintering time can be controlled to form a sintered glass sheet that is substantially free of voids and bubbles.

That is, as used in the present specification, sintering refers to a process of heating glass dust particles below their melting point (solid state sintering) until the particles adhere to each other. Annealing is a process that cools the glass after formation to release internal stress. Sintering and annealing can be performed sequentially using the same or different equipment.

The glass sheet forming process can be controlled to minimize strain (i.e., sag) of the dust sheet and the obtained glass sheet. One way to minimize strain is to have the dust sheet pointing vertically during the sintering process. According to a particular embodiment, the angle of pointing of the dust sheet relative to the vertical orientation may be less than 15 degrees (ie, such as less than 10 or 5 degrees). Another way to minimize strain is to apply tensile stress to the dust sheet and/or the glass sheet during the sintering action. The carrier tape can be applied, for example, by a pinch roller or a jaw to apply tensile stress in the plane of the major surface. The tensile stress can be applied to the dust sheet in a magnitude effective to draw the dust sheet substantially flat.

In addition to minimizing the strain induced by gravity, the application of tensile stress can also produce a visible effect on the sintering process. During the sintering process, the density of the dust flakes increases as the glass flakes are formed. To preserve mass, the increase in density is accompanied by an overall reduction in volume. In the absence of tensile stress, the dust sheet will exhibit significant lateral shrinkage. By applying a tensile stress to the dust sheet, the volume change can be achieved mainly by the change in thickness. Further, by applying tensile stress to the dust sheet during the sintering process, it is possible to sinter the non-vertical-oriented dust sheet without significant risk of deformation.

A variety of different dust sheet sintering devices can be utilized, including resistance heating and inductive heating devices to sinter the dust sheets. Both the dust sheet and the thermal history of the glass sheet can affect the final thickness, composition, compositional homogeneity and other chemical and physical properties of the final product. The glass sheet can be formed by applying heat to one or both of the major surfaces of the dust sheet. Various parameters can be controlled during the sintering process, including temperature and temperature profile, time and atmosphere.

The sintering temperature may be selected from those skilled in the art, for example, depending on the composition of the dust sheet to be sintered, but the sintering temperature may range from about 1000 ° C to 1900 ° C. At the same time, a homogeneous temperature profile can be achieved by resistive and inductive heat sources and can be used to create homogeneity within the final glass sheet. "Homogeneous temperature profile" means that the sintering temperature changes by less than 20% (ie, less than 10 or 5%) over a predetermined sample area or sample volume.

In a specific embodiment in which the edge of the dust sheet is partially held and guided by the dust sheet guiding device, the edge portion is generally not sintered by the sintering device. Conversely, the dust sheet sintering apparatus will only sinter the center portion of the dust sheet. For example, in one embodiment, a central 10 cm of a dust sheet having an average thickness of about 400 microns and a total width of 24 cm will be heated to produce a sintered glass sheet having a width of about 10 cm and an average thickness of about 100 microns. The dust sheet has an average density of about 0.5 g/cm3 before sintering. In a specific embodiment in which the edge portion is held and guided by the dust sheet guiding device, sintering may be performed between about 5 and 95% of the total area of the dust sheet by not sintering the edge portion of the dust sheet.

In addition to controlling the temperature and temperature profile during the sintering process, it is also possible to control the gas surrounding the dust/glass sheet. In detail, both the total pressure and the partial pressure of the appropriate sintering gas can be selected to control the sintering process. In some embodiments, the gas mixture being controlled may contain one or more reactive or inert gases such as, for example, He, O ₂ , CO, N ₂ , Ar or mixtures thereof.

During the sintering action, the dust sheet may be held in the sintering zone or moved continuously or semi-continuously through the zone. For example, in a continuous glass sheet forming process, the rate at which the dust sheet is released from the dust deposition surface can be equal to the rate at which the dust sheet passes through the sintering zone. Sintering may be carried out through one or more passages through the sintering zone using the same or different sintering conditions. The distance from the heater to the surface of the dust may range from about 1 mm to 10 mm (eg, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm).

Once formed, the glass sheet can be divided into discrete segments by a suitable cutting device. For example, a laser can be utilized to cut the glass sheet into smaller pieces. In addition, the sintered glass can be subjected to one or more post-sintering processes, such as edge removal, plating, polishing, etc., before or after cutting. The long strip of sintered glass sheets can be rolled into a roller shaft by a winding device. Space materials, such as paper sheets, cloth, plating materials, etc., may be inserted between adjacent glass surfaces in the roller shaft as needed to avoid direct contact therebetween.

The processes and apparatus disclosed herein are suitable for making dust sheets and sintered glass sheets containing a high percentage of cerium oxide, such as "high cerium oxide" glass sheets. By "high cerium oxide" is meant at least 50 mole %, for example more than 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98, 99, 99.5 or 99.9 mole % yttria glass. Glass ingredients.

The sintered glass sheet which can be formed into an elastic shape comprises a long glass strip. The sintered glass sheet, such as a high cerium oxide glass sheet, may have an average thickness of 150 microns or less. An exemplary glass sheet has a thickness of 10 μm. By controlling the width of the deposited dust layer, the width of the sintering zone, and the amount of deposition time, both the width and length of the sintered glass sheet can be independently controlled. The length of the glass sheet can range from about 2.5 cm to 10 km. The width of the glass sheet can range from about 2.5 cm to 2 m, which represents about 9 to 95% of the width of the dust sheet.

This process can be used to form glass sheets of high surface quality (i.e., glass sheets having low surface ripple, low surface roughness, and substantially no scratches). The foregoing process may include an initial step of forming a dust sheet on a roller shaft and a final step of winding the sintered, elastic glass sheet onto the roller shaft, and may be referred to as a "roller to roller" process. The resulting glass flakes comprising high yttria glass flakes can be characterized by a number of properties including composition, thickness, surface roughness, surface uniformity and flatness.

Roughness and other surface characteristics can be measured using contact or non-contact methods. The contact method involves dragging the measuring point pen across the surface of the sample and may include an instrument such as a profilometer. Exemplary non-contact methods include interferometry, conjugated focal microscopy, electrical capacitance, and electron microscopy.

Surface measurement data including surface roughness was measured using a Zygo white light interferometer microscope (New View 5000, Zygo Corporation, Middlefield, Conn.). The surface roughness calculation is based on the roughness profile filtered from the original profile and contains the calculated average line.

The roughness profile contains n ordered, equidistant spaced points along a one or two dimensional trace, and yi is the vertical distance from the average line or plane to the ith data point. The height is in the upward direction and the body material is assumed to be positive. That is, as the user of the present disclosure, Ra is the arithmetic mean of the absolute values, that is, as expressed by Equation 1, and Rq is the root mean square (rms) roughness, that is, as expressed by Equation 2.

In an exemplary glass sheet, the average Ra and Rq values were 1.11 and 1.41 nm, respectively, on the sample area measured at 0.18 x 0.13 mm ² , and the corresponding standard deviations were 0.23 and 0.28 nm. In a further exemplary glass sheet, the average Ra and Rq values were 0.59 and 0.78 nm on the sample area measured at 0.16 x 0.12 mm ² , respectively. These data were measured on the deposited surface of the sintered glass sheet. In many embodiments, the average surface roughness (Ra) on one or both of the major surfaces is less than 1 nm, although the average surface roughness can range from about 1 to 5 nm. The sample-to-sample variability in the roughness data may be due to manipulation or fragmentation, especially prior to sintering.

The uniformity of the glass sheet may be affected by the presence of substantially parallel protrusions on one or both major surfaces of the glass sheet. The projections are formed parallel to the manufacturing direction of the dust sheet and are optically representative of the regional physical thickness difference. The projections are optically observable only when the glass sheet is viewed at an angle normal to the major surface. It should be noted that when the glass piece is viewed in accordance with the incident normal, the thickness variation is substantially non-visible. Therefore, at the incident normal, what is seen is a homogeneous refractive index.

The protrusions are characteristic of the dust sheet forming process and are not intended to be limited by theory and are believed to be the articles of the burner configuration. Since the protrusions are believed to be unique to a particular burner geometry, they can be used as fingerprints for process identification.

The Surfcom 2000SD (Carl Zeiss) profile and roughness profile system can be used to obtain profile data. 2 and 3 are surface line scan results of an exemplary sintered glass sheet. These surface line scans are measured on the deposition surface of the glass sheet. Figure 2 shows a cross-sectional scan of a surface protrusion having an overall height of about 40 microns and a width of about 9 mm at the substrate. Figure 3 shows a cross-sectional scan of adjacent surface protrusions, which has an overall height of between about 3 and 5 microns and a width ranging from about 1 to 2 mm at the substrate.

According to an embodiment, the protrusions are characterized by an overall height in the range of 1 to 100 microns (eg, 1, 2, 5, 10, 20, 50 or 100 mm).

That is, as used in the present disclosure, "dust layer" means a coating of glass particles which are substantially uniformly distributed and selectively bonded to each other. The laminate typically has an average total thickness greater than or equal to the average diameter of the individual particles. In addition, the dust layer may comprise a single layer of dust having a substantially homogeneous composition or multiple layers of dust, each having a substantially homogeneous composition.

In a particular embodiment wherein the dust layer comprises multiple layers, one glass particle species can form a first dust layer and another glass particle species can form a second dust layer adjacent to the first dust layer. Therefore, individual dust layers can have different compositions and/or other properties. In addition, in the interface between the first layer and the second layer, since the two kinds of particle species may be mixed, the composition and/or properties at the interface of the successive layers may deviate from the individual stacks. The volume value associated with the layer.

References to "glass sheets" in this disclosure include both sheet materials (i.e., dust sheets) containing a plurality of glass dust particles and sheet materials made of sintered glass. That is, as is well known in the art, a sheet has two major opposing surfaces, which are generally substantially parallel to each other, and each having an area greater than the other surface. The distance between the two major surfaces at a certain location is the thickness of the sheet at that particular location. The sheet may have a substantially uniform thickness between the major surfaces, or the thickness may vary spatially uniformly or non-uniformly. In some other specific embodiments, the two major surfaces can be non-parallel, and one or both of the major surfaces can be planar or curved.

That is, as used in this disclosure, "sintered glass" refers to a glass material that has glass materials of the same chemical composition and microstructure under standard temperature and pressure (STP) conditions (273K and 101.325 kPa). Density of at least 95% of the theoretical density (Dmax). In some embodiments, the desired sintered glass has a density of at least 98%, 99%, or 99.9% of Dmax at STP.

The use of glass dust deposits to form ultra-thin glass sheets and the sinter processing process are disclosed in the U.S. Patent Application Serial No. 11/800,585, filed on May 7, 2007, the disclosure of which is hereby incorporated by reference.

As used herein, the terms "a", "an", and "the" are meant to refer to the plural referents unless otherwise indicated in the context. For example, the term "metal" encompasses two or more "metal" examples, unless explicitly stated in the text.

The range indicated herein is "about" a particular value, and/or to "about" another particular value. When expressed in terms of ranges, the examples include a particular value and/or to another particular value. Similarly, when a value is expressed as an approximate value, by using the preamble "about", one understands that a particular value forms another. It is further understood that each endpoint of the scope is meaningful relative to the other endpoint and is independent of the other endpoints.

Except as otherwise clear to the narrator, it is not intended to interpret any of the methods described herein as being required to perform the steps in a particular order. Therefore, where a method request item does not actually recite its steps in a certain order or in the scope or specification of the patent application, it is not specifically stated that the steps should be limited to a particular order, that is, no Reference should be made to any particular order.

It should be noted that the listing of elements of the invention is "operating" or "configuring" in a particular manner. In this regard, the element is "operated" or "configured" to dictate that a particular property or function is a structural list, rather than an enumeration of the intended use. More specifically, the reference to the element in which it is "operated" or "configured" refers to the current physical state of the component and can be used as an explicit list of structural features of the component.

example

The invention will now be further illustrated by the following examples.

Example 1: Making a single layer of dust sheet

Five linear burners were utilized to produce a dust layer containing 99+ moles of cerium oxide. The five 2.5 cm wide burners were placed adjacent to the array of burners to create a uniform, 12.5 cm wide dust flow. Each burner contains nine parallel gas nozzle rows. The diameter of each of the gas nozzles was measured to be 0.075 cm.

A precursor gas mixture containing OMCTS (5 g/min) entrained by N ₂ (20 SLPM) flows through the midline of the nozzles. Oxygen flows through three adjacent nozzle rows on each side of the centerline course. The oxygen flow through the adjacent course is 5 SLPM, and the oxygen flow through the next one pair is 20 SLPM. The gas stream passing through the last (outer) nozzle line contains a mixture of CH ₄ (12SLPM) and O ₂ (10SLPM).

The burners are disposed about 10 cm from the deposition surface of the cylindrical dust receiving device. The dust receiving device has a diameter of about 38 cm and a side wall thickness of about 0.64 cm. The dust receiving device was rotated to provide a linear surface speed of 1 mm/sec.

Dust from the burner array was directed to the deposition surface and a dust layer of about 200 microns thick and 15 cm wide was deposited. The average density of 13 cm in the center of the dust sheet was about 1.1 g/cm ³ . The 13 cm wide dust sheet produced at a higher density was released from the drum and expanded by air flow by an air knife. The air knife supplies about 20 SLPM of air through a 25.4 cm wide air knife body and is guided to the deposition surface. The dust sheet is manually taken by the peripheral edge and guided to the winding drum. The winding drum has a diameter of about 41 cm. A five meter long piece of dust is wound around the drum.

Example 2: Sintered single layer dust sheet

A dust sheet having a thickness of about 400 μm as described in Example 1 above was produced. This thickness is increased by reducing the rotational speed of the dust receiving device and increasing the OMCTS flow.

A dust sheet measuring about 1.2 m long and 7.6 cm wide is sintered in such a manner that the peripheral edge of the dust sheet is first held between the rollers to maintain contact along the length of the sample in the sintering zone, and then The dust sheet is passed through a heat source, and the dust sheet is heated to about 1500 ° C to form a densified, clean, sintered glass. The sintered glass has a final thickness of about 100 microns.

Sintered flakes having unsintered peripheral edges are removed from the grip rollers while the unsintered edges are trimmed with a laser and run along the length of the flakes at about 3 mm/s.

Example 3: Effect of process conditions on the thickness and density of dust sheets

The designed experiment was carried out in the following manner, (i) the rotational speed of the dust receiving device, (ii) the distance from the burner to the deposition surface, and (iii) the longitudinal direction of the outermost burner (ie, longitudinal The O ₂ flow in rows 1 and 9) is systematically changed. The effect of these variables on the thickness and density of the obtained dust sheets was measured, and the data can be as shown in Table 2. Using the selected parameters, i.e., as seen from the listed data, the thickness of the dust sheet was varied from about 250 to 700 microns, and the bulk density of the dust sheet was varied from about 0.35 to 0.7 g/cm ³ . In general, the thickness and density of the dust sheet will increase as the speed of the dust receiving device slows down.

During the sintering/annealing process of forming the glass sheet, typically the thickness of the dust sheet is reduced (and increased in density) by about 4 times, i.e., as a multiple of about 3 to 5.

Example 4: Multi-component glass

By introducing titanium, and optionally a phosphorus precursor, into the OMCTS stream to produce a composition having binary (SiO ₂ /TiO ₂ ) and ternary (SiO ₂ /TiO ₂ /P ₂ O ₅ ) components. Ingredients glass piece. The composition of the multi-component high cerium oxide glass flakes is expressed as a percentage by weight of the individual components as listed in Table 3. In Table 3, the content of yttrium oxide is determined by gravity measurement, while the content of titanium and phosphorus is determined by inductively coupled plasma/direct coupled plasma (ICP/DCP). Due to the use of different measurement techniques, the composition of the individual components is not 100% by weight in total.

It is apparent to those skilled in the art that the present invention is capable of various changes and modifications without departing from the spirit and scope of the invention. Those skilled in the art will recognize that variations, combinations, and modifications of the disclosed embodiments of the present invention are intended to be included within the scope of the appended claims.

100. . . Forming a glass piece device

110. . . Dust supply device

120. . . Dust receiving device

130. . . Dust sheet guiding device

140. . . Dust sintering device

150. . . Dust particles

152. . . Dust layer

154. . . Dust sheet

156. . . Glass piece

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing an apparatus for forming an ultra-thin glass piece.

2 is a surface line scan of a sintered glass sheet in accordance with a particular embodiment.

3 is a surface line scan of a sintered glass sheet in accordance with a further embodiment.

100. . . Forming a glass piece device

110. . . Dust supply device

120. . . Dust receiving device

130. . . Dust sheet guiding device

140. . . Dust sintering device

150. . . Dust particles

152. . . Dust layer

154. . . Dust sheet

156. . . Glass piece

Claims (5)

A high cerium oxide glass sheet having two major opposing surfaces and comprising: at least 50 mole % cerium oxide; an average thickness between two major opposing surfaces of about 150 microns or less, and further comprising at least one from Attributes selected in the group: (i) an average surface roughness above about 1 nm or less of at least one of the two major surfaces; (ii) at least one of the two major opposing surfaces formed on the two major surfaces A substantially parallel surface protrusion on the person; and (iii) a length of at least 2.5 cm and a width of at least 2.5 cm. The high cerium oxide glass sheet of claim 1, wherein the glass sheet comprises at least 80 mol% of cerium oxide. The high cerium oxide glass sheet of claim 1, wherein the glass sheet has an average thickness of less than about 50 microns. A high cerium oxide glass sheet having two major opposing surfaces and comprising: at least 50 mole % cerium oxide; an average thickness between two major opposing surfaces of about 150 microns or less; and above An average surface roughness of at least one of the major surfaces of about 1 nm or less. a high cerium oxide glass sheet having two major opposing surfaces and comprising: at least 50 mole % cerium oxide; an average thickness between two major opposing surfaces of about 150 microns or less; and a plurality of formed in the A substantially parallel surface protrusion on at least one of the two major opposing surfaces.