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WO2009108302A1 - Procédé destiné à prévoir la conformabilité d’une feuille de matériau à une surface de référence - Google Patents

Procédé destiné à prévoir la conformabilité d’une feuille de matériau à une surface de référence Download PDF

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Publication number
WO2009108302A1
WO2009108302A1 PCT/US2009/001166 US2009001166W WO2009108302A1 WO 2009108302 A1 WO2009108302 A1 WO 2009108302A1 US 2009001166 W US2009001166 W US 2009001166W WO 2009108302 A1 WO2009108302 A1 WO 2009108302A1
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Prior art keywords
sheet
gaussian curvature
glass
maximum
magnitude
Prior art date
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Ceased
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PCT/US2009/001166
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English (en)
Inventor
Christian L Stauter
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Corning Inc
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Corning Inc
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Filing date
Publication date
Application filed by Corning Inc filed Critical Corning Inc
Priority to CN200980114488.8A priority Critical patent/CN102007370B/zh
Priority to JP2010548704A priority patent/JP5416143B2/ja
Publication of WO2009108302A1 publication Critical patent/WO2009108302A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
    • G01B21/20—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring contours or curvatures, e.g. determining profile

Definitions

  • the present invention relates to a method for predicting the confo ⁇ nability of a sheet of material of arbitrary shape to a reference surface. More particularly, the present invention relates to a method for predicting the ability of a glass sheet, such as a glass sheet suitable for use in a flat panel display, to conform to a support surface that may be used in the processing of the sheet.
  • LCDs liquid crystal displays
  • SEDs surface conduction electron emitter displays
  • FEDs field emission displays
  • LCDs liquid crystal displays
  • the substrate needs (other than being transparent and capable of withstanding the chemical conditions to which it is exposed during display processing) of the two matrix types vary.
  • the first type is intrinsic matrix addressed, relying upon the threshold properties of the liquid crystal material.
  • the second is extrinsic matrix or active matrix (AM) addressed, in which an array of diodes, metal-insulator-metal (MIM) devices, or thin film transistors (TFTs) supplies an electronic switch to each pixel.
  • AM extrinsic matrix or active matrix
  • MIM metal-insulator-metal
  • TFTs thin film transistors
  • two sheets of glass form the structure of the display.
  • the separation between the two sheets ' is the critical gap dimension, of the order of 5-10 ⁇ m.
  • the individual glass substrate sheets are typically less than about 0.7 mm in thickness.
  • a method of determining the conformability of a glass sheet to a surface comprising determining a shape of the sheet, using the shape to calculate a Gaussian curvature magnitude for a plurality of points on the sheet, subtracting the plurality of Gaussian curvature magnitudes for the sheet from corresponding Gaussian curvature magnitudes for a support surface to determine a Gaussian curvature magnitude difference for each point of the plurality of points on the sheet, selecting a maximum Gaussian curvature magnitude difference for the sheet from the plurality of Gaussian curvature magnitude differences, comparing the maximum Gaussian curvature magnitude difference to a predetermined maximum threshold, and classifying the sheet as acceptable if the maximum Gaussian curvature magnitude is equal to or less than the threshold or unacceptable of the maximum Gaussian curvature magnitude is greater than the maximum threshold.
  • the sheet shape may be characterized via a gravity free approach, such as placing the sheet in a neutral density fluid, or supporting the sheet on a bed of adjustable supports, such as adjustable pins.
  • FIG. 1 is a perspective view, in partial cross section, of a fusion downdraw apparatus for forming thin glass sheets.
  • FIG. 2 is a cross sectional side view of a glass assembly including a frit seal that is sealed with a laser.
  • FIG. 3 is a cross sectional side view of an apparatus for measuring the shape of a sheet or material (e.g. a glass sheet) in a neutral density "gravity free” environment.
  • FIG. 4 is a cross sectional side view of an apparatus for measuring the gravity free shape of a sheet of material (e.g. a glass sheet) using a "bed of nails”.
  • FIG. 5 is a perspective view of a sheet of material comprising a longitudinal hump positioned over a flat reference surface, the sheet of material with the hump representing a developable surface.
  • FIG. 6 is a perspective view of a sheet of material comprising a central peak or bubble positioned over a flat reference surface, the sheet of material with the peak representing a non-developable surface.
  • FIG. 7 A and 7B are perspective views of a developable cylindrical surface (FIG. 7A) that can be unrolled into a flat (planar) surface as shown in the perspective view of FIG. 7B.
  • FIG. 8 A is a perspective view of a non-developable sphere.
  • FIG. 8B shows a perspective view of the tearing that must occur to flatten one half (a hemisphere) of the sphere of FIG. 8 A, making the hemispherical shape undevelopable.
  • FIG. 9 is a qualitative plot of the force to flatten a developable vs. a non- developable sheet of material (e.g. a glass sheet).
  • FIG. 10 is a perspective view of a moving "window" used to characterize the Gaussian curvature of a sheet of material (e.g. a sheet of glass) that may have a broad distortion but low magnitude distortion.
  • a sheet of material e.g. a sheet of glass
  • FIG. 11 is a three dimensional plot of a sheet of otherwise flat material comprising a z-axis peak.
  • FIG. 12 is a three dimensional plot of the Gaussian curvature of the surface of FIG. 9.
  • FIG. 13 is a graph showing the relationship between the height and the lateral dimensions (diameter) of a symmetric bubble is a glass sheet, the bubble having a maximum Gaussian curvature magnitude of IxIO "8 mm "2 .
  • an overflow trough member of forming wedge 20 includes an upwardly open channel 22 bounded on its longitudinal sides by wall portions 24, which terminate at their upper extent in opposed longitudinally-extending overflow lips or weirs 26.
  • the weirs 26 communicate with opposed outer ribbon forming surfaces of wedge member 20.
  • wedge member 20 is provided with a pair of substantially vertical forming surface portions 28 which communicate with weirs 26, and a pair of downwardly inclined converging surface portions 30 which terminate at a substantially horizontal lower apex or root 32 forming a straight glass draw line. It will be understood that surface portions 28, 30 are provided on each longitudinal side of the wedge 20.
  • Molten glass 34 is fed into channel 22 by means of delivery passage 36 communicating with channel 22.
  • the feed into channel 22 may be single ended or, if desired, double ended.
  • a pair of restricting dams 38 are provided above overflow weirs 26 adjacent each end of channel 22 to direct the overflow of the free surface 40 of molten glass 34 over overflow weirs 26 as separate streams, and down opposed forming surface portions 28, 30 to root 32 where the separate streams, shown in chain lines, converge to form a ribbon of virgin-surfaced glass 42.
  • Pulling rolls 44 are placed downstream of the root 32 of wedge member 20 and are used to adjust the rate at which the formed ribbon of glass leaves the converging forming surfaces and thus determine the nominal thickness of the ribbon.
  • the pulling rolls are preferably designed to contact the glass ribbon at its outer edges, specifically, in regions just inboard of the thickened beads which exist at the very edges of the ribbon.
  • the glass edge portions which are contacted by the pulling rolls are later discarded from the sheet.
  • a pair of opposed, counter-rotating pulling rolls are provided at each edge of the ribbon.
  • the ribbon experiences intricate structural changes, not only in physical dimensions but also on a molecular level.
  • the change from a thick liquid form at, for example, the root of the forming wedge, to a stiff ribbon of approximately one half millimeter of thickness is achieved by a carefully chosen temperature field or profile that delicately balances the mechanical and chemical requirements to complete the transformation from a liquid, or viscous state to a solid, or elastic state.
  • the ribbon is cut at cut line 48 to form a glass sheet or pane 50.
  • the glass ribbon is drawn from the forming wedge by rollers that contact only edge portions of the ribbon, providing opportunity for the central portion of the ribbon to warp.
  • This warping may be caused by movement of the ribbon, or by the interplay of various thermal stresses that may manifest within the ribbon.
  • vibrations introduced into the ribbon by the downstream cutting process may propagate upward into the visco-elastic region of the ribbon, be frozen in to the sheet, and manifest as deviations in the planarity of the elastic ribbon.
  • Variations in temperature across the width and/or length of the ribbon may also lead to deviations in planarity. Indeed, stresses that are frozen into the ribbon may be partially relieved when individual sheets of glass are cut from the ribbon, also resulting in a non-flat surface, hi short, the shape of a sheet of glass derived from the ribbon is dependent upon the thermal history of the ribbon during the transition of the ribbon through the visco-elastic region, and that thermal history may vary. Such changes in stress and/or shape may be detrimental to processes which rely on dimensional stability, such as the deposition of circuitry onto a substrate, such as is found in the manufacture of liquid crystal displays. For example, in the manufacture of liquid crystal displays, large glass sheets cut from the drawn ribbon may themselves be cut into a plurality of smaller sections.
  • Each division may therefore result in a relief or redistribution of stress, and a subsequent shape change.
  • the resultant sheet may generally be considered flat, the sheet may in fact exhibit valleys and peaks across its surface that may interfere with flattening the sheet during subsequent processing. It is desirable therefore that a method be devised wherein the shape of a glass sheet cut from the ribbon may be accurately determined. The information thus obtained may used to modify the thermal history of the glass ribbon being drawn.
  • Display manufacturers receive the thin glass sheets from the glass manufacturer and further process the sheets to form a display device, or some other glass sheet- containing device.
  • a display device or some other glass sheet- containing device.
  • one or more layers of organic materials 54 are deposited on a first glass sheet 56 (e.g. substrate 56).
  • This first glass sheet is often termed the backplane.
  • Backplane 56 may also comprise thin film transistors (TFTs) and electrodes (sot shown) for supplying an electric current to the organic layers and causing them to illuminate.
  • TFTs thin film transistors
  • electrodes sin shown
  • the organic layers must be hermetically separated from the ambient environment.
  • the organic layers are sealed within a glass envelop formed by backplane 56, a second glass sheet 58, sometimes referred to as the cover sheet or cover plate and a sealing material 60 disposed between the backplane and the cover sheet.
  • Several sealing methods may be used to connect the backplane to the cover plate, including the use of adhesives. While easy to apply and use, adhesives suffer from the necessary hermeticity to ensure the device exhibits a commercially viable lifetime before failure. That is, moisture and/or oxygen may eventually penetrate the adhesive seal, leading to a degradation of the organic layer(s), and the display device. [0029] A more viable approach is to form a frit seal between the backplane and the cover sheet. In accordance with this approach, a line of a glass frit paste sealing material is dispensed over the cover plate in the form of a loop or frame, after which the fritted cover plate is heated to adhere the frit to the cover plate.
  • Frit 60 is then heated, such as with laser 64 emitting laser beam 66, to soften the frit and form a hermetic seal between backplane 56 and cover 58.
  • the substrates are required to be flat during such forming processes.
  • the backplane substrate is often vacuumed down onto a planar support surface for processing.
  • FIG. 3 illustrates an embodiment of a method of determining the shape of a glass article, such as a glass sheet, according to embodiments of the present invention. In accordance with the embodiment of FIG.
  • glass sheet 70 is positioned in container 72 containing fluid 74.
  • Glass sheet 70 may be positioned on the surface of the fluid, or submerged within the fluid, as described in more detail hereinbelow.
  • the glass sheet has a pre-determined average density and a predetermined average refractive index.
  • the fluid also has a pre-determined average density and a pre-determined average refractive index.
  • the average density of the fluid is at least about 85% of the average density of the glass sheet; more preferably at least about 90%; still more preferably at least about 95%.
  • Fluid 74 is said to be of neutral density relative to glass sheet 48 when the average density of the fluid is at least about 85% of the average density of the glass sheet, and the glass sheet is said to be neutrally buoyant, in that the glass sheet should remain in a given position within fluid 74 without mechanical support for a time sufficient to complete a given measurement.
  • Suitable fluids for example, are available from Cargille Inc., which manufactures refractive index matching liquids, immersion liquids, optical coupling liquids, refractometer liquids and other specialty liquids. Such liquids are advantageous in that they are typically non-toxic and the density of the fluid is easily tuned, such as by increasing or decreasing the concentration by evaporation, for example.
  • Tuning of the fluid density may also be accomplished by mixing two or more fluids having different densities such that a desired pre-determined average density of the mixture is achieved.
  • Eagle 2000TM glass manufactured by Corning Incorporated has an average density of about 2.37 g/cc.
  • Several fluids, such as a first fluid having an average density of 2.35 g/cc and a second fluid having an average density of 2.45 g/cc, may be mixed in amounts effective to obtain a third fluid having an average density substantially equal to 2.37 g/cc.
  • any fluid or fluids having the requisite properties of density may be used.
  • sensor 76 is used to measure a distance from the sensor to a surface of the glass sheet.
  • Glass sheet 70 comprises a first side 78 facing sensor 76 (the sensor side), and a second, non-sensor-facing side 80.
  • sensor side 78 may be referred to as top side 78 and non-sensor side 80 may be referred to as bottom side 80.
  • the average refractive index of fluid 74 be detectably different than the average refractive index of glass sheet 70.
  • the allowable difference between the average refractive index of the fluid and the average refractive index of the glass is determined by such factors as the sensitivity of sensor 76.
  • a thin film or coating may be applied to a surface of glass sheet 70, preferably applied to bottom side 80 of the sheet, so that measurements of the distance between the sensor and the glass-coating interface may be obtained. Measurement of the coating itself, such as if the coating was adhered to top side 78 (sensor-side), may induce erroneous measurements, as one then measures the surface of the film rather than the surface of the glass.
  • the coating is preferably, though not necessarily, opaque, and may comprise, for example, a paint, ink or dye. A white, opaque coating has been found to achieve superior results.
  • any coating that has a refractive index detectably different than the refractive index of the fluid may be acceptable.
  • the coating may comprise a polymer film wherein the polymer has an average refractive index detectably different from the average refractive index of the fluid. It is desirable that any stress applied by the coating to glass sheet 70 be insufficient to cause additional deformation of the glass sheet. For this reason, the coating may be applied to the glass sheet in a discontinuous fashion, such in a series of dots, lines or other shapes.
  • a thickness of the glass sheet may also be measured as a function of location on the glass sheet, and combined with the film-glass interface distance data to produce a surface contour map for the sensor side of the glass sheet.
  • sensor 76 may be used to measure a distance from the sensor to a surface of the glass sheet.
  • Sensor 76 may be used to measure the distance d ⁇ between the sensor and top surface 78 of the glass sheet, or sensor 76 may be used to measure the distance d 2 between the sensor and bottom surface 80 of the glass sheet.
  • Sensor 76 may comprise, for example, a laser displacement sensor.
  • sensor 76 may comprise other devices as are known in the art for measuring distances, such as an acoustic sensor.
  • Laser devices may include simple laser ranging devices, or more elaborate devices, such as, for example, a Michelson interferometer.
  • the sensor may be time-based wherein a sensed energy, such acoustic, having a known velocity in the fluid, is timed.
  • a suitable sensor for example, is the LT8110 confocal laser displacement sensor manufactured by Keyence Corporation of America.
  • sensor 76 may be positioned above the surface of the fluid, the sensor is preferably in contact with the fluid, therefore advantageously eliminating the air-fluid interface at fluid surface 82. Sensor 76 may be completely immersed in the fluid.
  • BoN bed-of- nails
  • the heights of the pins are adjusted until each pin supports a specified target weight. For instance, a target weight for an even and flat substrate resting on equally distributed pins might be an equal fraction of the entire weight of the substrate. However, each target weight likely will be different from the next, and the target weights may be determined using a stress analysis based on finite element analysis.
  • the target weights may be determined using a stress analysis based on finite element analysis.
  • the gravity-free shape may be measured by optical means that scan the substrate surface and measure the heights over the entire surface, at and between the pins.
  • a problem with a BoN gauge is that changing the height of a single pin potentially changes the weight on all the other pins. For instance, in the extreme example of a single pin being raised high enough to raise the substrate above the tops of assorted pins, the assorted pins would no longer bear any weight, as they do not contact the substrate. Therefore, if the height on one pin is adjusted so that the target weight is supported momentarily, the amount of weight supported will be changed when the height on another pin is changed. If the system is adjusted manually, it will take a tremendous amount of time to adjust the pins. If the system is automated, an algorithm is needed to adjust the pins.
  • each pin is adjusted separately. Each pin height is adjusted until the target weight is achieved. This single adjustment action is done one pin at a time, from the first pin to the last pin. However, since adjusting one pin changes the load on all the others, this procedure must be repeated time and time again, each cycle correcting for minor deviations introduced in the previous cycle.
  • methods for adjusting the pin heights to simultaneously support the target weights for all pins is included, hi particular, systematic calculation and execution of appropriate pin height adjustments for the array of pins is provided for.
  • their heights are at the gravity-free height for that particular substrate.
  • the array of pins at their gravity-free heights provides a measurement of the gravity-free shape, and potential shape distortion, if any.
  • Height adjusters of the pins also track the heights of the pins, obviating the need for additional height measurement means, such as an optical scanner.
  • all pins may be adjusted at the same time. No evaluation of the pin force is necessary until all the pins are adjusted.
  • the pin force is the upward force of the pin, which equals the downward force supported by the pin, if the pin is not in motion.
  • FIG. 4 a block diagram illustrates an exemplary bed of nails shape measurement gauge 100 in accordance with one or more embodiments of the present invention.
  • the BoN gauge 100 may include a plurality of pins 110, having at least three pins 110, a gauge base 120, and a processor 130.
  • a flexible plate-like object serves as the measurement subject 140, which here is depicted as glass substrate 140.
  • the substrate 140 rests on top of the plurality of pins 110, and as the measurement subject 140 flexes under gravity, each pin 110 bears a specific weight.
  • Each pin 110 includes a load cell 112 to measure the specific weight supported by the pin 110.
  • the load cell 112 may be mounted on top of a height adjuster 114, which is a device, preferably motorized, that adjusts the height of the pin 110 in a known manner. Other arrangements are conceivable, such as having the load cell 112 underneath, and accounting for the weight of the height adjuster 114.
  • Each load cell 112 may transmit to processor 130 via circuitry 116 measurement signals 132 relating to the measured pin force, and the processor 130 then may perform an algorithm to calculate the necessary height adjustments for each pin 110.
  • the processor 130 may transmit adjustment signals 134 to each height adjuster 114 via circuitry 116 to execute the calculated height adjustments.
  • the better the algorithm the sooner the load cells 112 will read the target load.
  • the present invention takes advantage of the fact that changing the pin height of a single pin 110 typically changes the load on all the pins 110. Say there are N pins 110 used in the gauge 100. The object is to find the pin heights such that the forces on each pin 110 are at a specific value. For instance, for a substantially planar substrate 140 of relatively even thickness and density, an approximately equal distribution of mass may be assumed so that the specific weight value may equal 1/N of the substrate weight, given an equal distribution of the N pins 110.
  • three of the pins 110 will not be adjusted and hence they are stationary for each adjustment cycle.
  • the three stationary pins 110 fix a reference plane, for which reason these pins 110 should not lie on a line.
  • three pins will remain fixed. These may be adjusted in subsequent cycles. Thereafter, all remaining N-3 pins 110 may be adjusted as calculated below to also support the specific weight.
  • Calculating the pin height adjustments for the remaining N-3 pins 110 can be considered a set of simultaneous equations, with N-3 equations and N-3 unknowns which relate the change in pin heights to the change in pin weights.
  • the three pins are fixed to define a reference plane with respect to which the equations relate. From a physics perspective, the sum of forces, sum of moments about one axis, and sum of moments about another axis represent three equations that must be satisfied. By fixing these three pins, these pins systematically will have their targeted weight satisfied by adjusting the others, which will have their target weight satisfied as well. From a geometry perspective, without fixing three points, rigid motion would be possible, though undesirable. Rigid motion could translate the substrate and rotate it about two different axes, which would yield more than one solution to the pin height adjustment set of equations. Thus, three points are fixed, so that there is only one solution to the pin height adjustments set of equations.
  • a sheet of material 200 such as a thin glass sheet
  • a sheet of material 200 such as a thin glass sheet
  • a longitudinal ridge 202 that extends along a "length" of the sheet, such as parallel to one edge of the sheet, the deviation of the ridge having a maximum deviation from a flat reference plane 204 of L+ ⁇ , as depicted in FIG. 6.
  • the ridge is shaped as comprising a portion of a cylinder.
  • a second sheet 206 comprise a concavity 208 (e.g.
  • a developable surface is a surface that can be flattened without stretching, compression or tearing of the surface.
  • a cylinder as shown in FIG. 7 A and discussed above, comprises a developable surface, since the cylindrical surface may be rolled out to lay flat without stretching or tearing of the surface (FIG. 7B).
  • a spherical surface (FIG. 8A) is non-developable. Try to lay flat a portion of a sphere, a hemisphere for example, and the hemisphere must stretch or tear along multiple boundaries to comply (FIG. 8B).
  • the sheet having the cylindrical ridge could be flattened to a planar table without deformation of the sheet, while conforming the second example sheet to the table would require deformation or tearing of the sheet.
  • Developable surfaces are surfaces that can be transformed into a plane surface through a transformation that preserves angles and distances. When a developable surface is transformed into a planar surface, no strain is induced into the surface.
  • a developable surface is a surface that may be formed from a planar surface without stretching, compressing or tearing of the surface.
  • characterizing a sheet of glass via its maximum warp may be sufficient to indicate that the sheet is non- flat, but is quite inadequate as a measure of how well the sheet may be forced into a planar configuration.
  • the Gaussian curvature describes how a surface deviates from a plane surface.
  • the mathematical derivation of Gaussian curvature is well known and will not be covered extensively here. It is more instructive to consider the practical implications of the Gaussian curvature. To begin, it is dependent only on how distances and angles are measured on the surface.
  • the surface comprises a bump or peak at that point; if the Gaussian curvature is negative, the surface comprises a saddle point. However, if the Gaussian curvature is zero, the surface at that point is equivalent to (behaves as) a flat surface.
  • a simple experiment serves to illustrate this difference.
  • a developable surface has a zero Gaussian curvature, and can be transformed to a planar surface without stretching, compression or tearing. If the surface can be flattened without inducing strain, the Gaussian curvature remains constant. Consequently knowing the magnitude of the Gaussian curvature of a surface can be instructive in understanding the degree to which one surface may conform to another surface.
  • the Gaussian curvature can be used to characterize the confo ⁇ nability of a sheet of glass to a reference surface, e.g. a surface by which the sheet is supported.
  • a reference surface e.g. a surface by which the sheet is supported.
  • the sheet is capable of conforming substantially to a support surface, implying that the magnitude of the Gaussian curvature of the sheet at each point of the sheet matches, or nearly matches, the magnitude of the Gaussian curvature of the support surface at each point of the support surface.
  • the reference surface is a plane
  • the sheet, to conform exactly to the reference (e.g. support) surface should also have a Gaussian curvature of zero at each point on the surface of the sheet.
  • the strain energy created in the sheet may, for example, cause buckling or stress-induced birefringence in the glass.
  • the Gaussian curvature magnitude of a singular peak or valley such as shown in FIG. 6 and exhibited by a sheet of glass resting on a support surface, such as a flat surface, would not change much, assuming the sheet experiences only gravity forces and the reaction forces of the table. This becomes even truer as the magnitude of the Gaussian curvature increases. As the magnitude of the Gaussian curvature increases, the resistance of the sheet to flattening increases and greater force must be employed to flatten the sheet.
  • FIG. 9 which qualitatively shows the relationship between sheet flatness and the force that has to be applied to achieve the corresponding flatness. Surfaces to the left of the vertical dashed line would be represented by developable shapes, whereas surfaces to the right of the line would be characterized as having non- developable shapes.
  • the Gaussian curvature of the sheet may be determined at each point.
  • the Gaussian curvature of a local area on the sheet can be determined using an osculating paraboloid method.
  • the sheet may include a relatively large area having even a small but finite ⁇ K associated with it.
  • the absolute value of ⁇ K may be integrated over a moving window on the surface and the result normalized to the area of integration. The resulting integrated value of K (K int ) may then be used as a measure of the shape of the sheet. That is,
  • FIG. 10 Such a situation is illustrated in FIG. 10, where the integration area S is moved over the sheet surface.
  • ⁇ K at each point of the sheet is simply the magnitude of the Gaussian curvature of the sheet at each point where the Gaussian curvature of the sheet is determined. ⁇ K may then be determined easily, without worrying about point-to-point correspondence between the sheet and the support. This case may arise, for example, during the deposition of TFTs in panels for displays. Supports for such deposition processes may weight several tons and be machined flat to extremely high tolerances.
  • FIG. 11 Shown in FIG. 11 is a three dimensional modeled plot of an otherwise flat sheet comprising a bubble (peak) defined by the equation
  • FIG. 12 illustrates the Gaussian curvature of the bubble of FIG. 11.
  • the maximum Gaussian curvature magnitude is represented by
  • FIG. 13 illustrates a plot of the diameter vs. height relationship for a symmetric bubble having a Gaussian curvature of 1x10 "8 mm "2 .
  • Bubbles having a height-diameter positioned to the right of the curve tend to exhibit good chucking behavior (capable of being flattened on a flat support via vacuum chucking), whereas bubbles having a height-diameter relationship to the left of the curve tend to exhibit poor chucking performance (e.g. vacuum leaks, incomplete flattening, etc.)- FIG. 13 shows that for a given diameter, a bubble should be below a certain height in order to be effectively flattened.
  • Experimental work has demonstrated that a maximum Gaussian curvature magnitude of 1x10 " mm " is a practical upper threshold for the maximum Gaussian curvature magnitude for thin sheets of display glass (having thicknesses less than about 1 mm).
  • the use of Gaussian curvature to characterize the conformability of a sheet of material, and in particular an elastic sheet of material such as a thin sheet of glass can be used to:

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
  • Joining Of Glass To Other Materials (AREA)
  • Surface Treatment Of Glass (AREA)
  • Laminated Bodies (AREA)

Abstract

La présente invention concerne un procédé de prédiction de la conformabilité d’une forme libre, telle qu’une vitre, à une surface. Le procédé utilise un procédé de mesure libre de gravité pour déterminer d’abord une forme de la feuille, l’amplitude de la courbe de Gauss de la feuille étant ensuite calculée. La courbe de Gauss de la feuille est comparée à une valeur maximale prédéterminée et il est décidé d’accepter ou de refuser la feuille en fonction des résultats de la comparaison.
PCT/US2009/001166 2008-02-28 2009-02-25 Procédé destiné à prévoir la conformabilité d’une feuille de matériau à une surface de référence Ceased WO2009108302A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN200980114488.8A CN102007370B (zh) 2008-02-28 2009-02-25 预测材料板相对于参比表面的顺应性的方法
JP2010548704A JP5416143B2 (ja) 2008-02-28 2009-02-25 シート材の基準面に対する共形化可能度を予測する方法

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US6741008P 2008-02-28 2008-02-28
US61/067,410 2008-02-28

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120053891A1 (en) * 2010-08-27 2012-03-01 Abbott Iii John Steele Methods and apparatus for estimating gravity-free shapes
WO2017204528A1 (fr) * 2016-05-23 2017-11-30 Corning Precision Materials Co., Ltd. Procédé de prédiction de la forme sans gravité d'une feuille de verre et procédé de gestion de la qualité de la feuille de verre sur base de la forme sans gravité

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8973402B2 (en) * 2010-10-29 2015-03-10 Corning Incorporated Overflow down-draw with improved glass melt velocity and thickness distribution
KR102035859B1 (ko) * 2014-05-28 2019-10-25 주식회사 펨토바이오메드 점도 측정 방법
CN113468782B (zh) * 2021-06-21 2023-04-07 上汽大众汽车有限公司 一种用于车辆碰撞评估的夹层玻璃有限元建模方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0977009A1 (fr) * 1997-04-25 2000-02-02 Riken Procede permettant d'etablir une distinction entre des erreurs de forme d'une surface courbe a forme libre
EP1030162A1 (fr) * 1998-08-19 2000-08-23 Riken Procede d'evaluation d'erreurs de forme dans une surface courbe libre

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU1791703C (ru) * 1987-10-30 1993-01-30 Центральный научно-исследовательский геологоразведочный институт цветных и благородных металлов Способ контрол состо ни длинномерного объекта
US5573446A (en) * 1995-02-16 1996-11-12 Eastman Kodak Company Abrasive air spray shaping of optical surfaces
JPH10269260A (ja) * 1997-03-24 1998-10-09 Honda Motor Co Ltd 形状データ検証方法
JP3418819B2 (ja) * 1998-01-13 2003-06-23 東芝セラミックス株式会社 プレート平坦度測定装置
US6727864B1 (en) 2000-07-13 2004-04-27 Honeywell International Inc. Method and apparatus for an optical function generator for seamless tiled displays
JP2004145674A (ja) * 2002-10-25 2004-05-20 Nippon Sheet Glass Co Ltd プレス曲げ成形型の型面の設計方法
JP4773713B2 (ja) 2004-11-17 2011-09-14 三菱重工業株式会社 成形型モデルの形状決定方法
US7225665B2 (en) * 2005-07-27 2007-06-05 Corning Incorporated Process and apparatus for measuring the shape of an article

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0977009A1 (fr) * 1997-04-25 2000-02-02 Riken Procede permettant d'etablir une distinction entre des erreurs de forme d'une surface courbe a forme libre
EP1030162A1 (fr) * 1998-08-19 2000-08-23 Riken Procede d'evaluation d'erreurs de forme dans une surface courbe libre

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120053891A1 (en) * 2010-08-27 2012-03-01 Abbott Iii John Steele Methods and apparatus for estimating gravity-free shapes
US9031813B2 (en) * 2010-08-27 2015-05-12 Corning Incorporated Methods and apparatus for estimating gravity-free shapes
WO2017204528A1 (fr) * 2016-05-23 2017-11-30 Corning Precision Materials Co., Ltd. Procédé de prédiction de la forme sans gravité d'une feuille de verre et procédé de gestion de la qualité de la feuille de verre sur base de la forme sans gravité
US11614323B2 (en) 2016-05-23 2023-03-28 Corning Incorporated Method of predicting gravity-free shape of glass sheet and method of managing quality of glass sheet based on gravity-free shape

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JP2011513727A (ja) 2011-04-28
JP5416143B2 (ja) 2014-02-12
CN102007370B (zh) 2013-03-13
KR101543053B1 (ko) 2015-08-07
TW201003036A (en) 2010-01-16
TWI392846B (zh) 2013-04-11
CN102007370A (zh) 2011-04-06

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