CN107848864B - Method and device for bending glass by microwave heating - Google Patents

Abstract

Methods and systems for automated forming of glass sheets are provided. The method includes preheating the glass, bending the glass via selective and focused beam heating using ultra-high frequency, high power electromagnetic waves and computer-implemented processing utilizing instantaneously acquired thermal and shape (position) data, and cooling the glass sheet to produce a glass sheet suitable for use in air and space vehicles.

Description

Method and device for bending glass by microwave heating

Cross Reference to Related Applications

This application is a continuation-in-part application entitled "Heating and Shaping System Using Microwave Focused Beam Heating" filed on 30/5 in 2013, U.S. patent application No.13/905,365. The entire contents of which are incorporated herein by reference.

Background

Technical Field

The present invention relates to a heating and bending (and/or shaping) system using microwave focused beam heating, and more particularly, to a glass line having at least two (e.g., at least three) heating furnaces. Wherein the first heating furnace is used for preheating one or more glass substrates to a first temperature; a second furnace, which is a glass forming furnace, maintains the substrate at the first temperature and controllably cools the one or more glass substrates using microwave focused beam heating and the first furnace or a third furnace heating and bending selected portions of the one or more glass substrates.

Also provided herein are methods for real-time monitoring of the temperature and bending of glass sheets to be formed.

Description of the Related Art

Bending devices, commonly referred to in the bending art as bending irons or forming irons, are well known in the art for shaping one or more glass sheets for use in the manufacture of monolithic and laminated transparencies for land, water, air and space vehicles. Methods for shaping glass substrates or sheets for use in the manufacture of transparencies for land and water vehicles generally comprise providing one or more glass sheets having stitched or smoothed edges and a predetermined size; moving a glass sheet supported on a bending iron through a furnace to heat soften the glass sheet; shaping the glass sheet; controllably cooling the shaped glass sheet to anneal or thermally temper the shaped glass sheet, and using the shaped glass sheet in the manufacture of transparencies for land or water vehicles. Methods for shaping glass substrates or sheets for use in the manufacture of transparencies for air and space vehicles generally comprise providing one or more glass sheets having a seamed or smoothed edge and a predetermined size; moving a glass sheet supported on a bending iron through a furnace to heat soften the glass sheet; shaping the glass sheet; controllably cooling the shaped glass sheet to anneal the shaped glass sheet; cutting the shaped glass sheet to a second predetermined size; stitching or smoothing the edges of the shaped glass sheet; chemically tempering the shaped glass sheet, or thermally tempering the shaped glass sheet, and using the tempered shaped glass sheet in the manufacture of transparencies for air or space vehicles.

The difference of interest in this discussion between shaping glass sheets for use with transparencies for land and water vehicles and shaping glass sheets for use with transparencies for air and space vehicles is that glass sheets for use with transparencies for land and water vehicles are cut to the desired dimensions prior to shaping or bending, whereas glass sheets for use with transparencies for air and space vehicles are cut to an oversized size prior to shaping and then cut to the desired dimensions after bending. For the sake of clarity, the process currently available for shaping glass sheets for use in transparencies for land and water vehicles is also referred to as the "cut-to-size" process, and the process currently available for shaping glass sheets for use in transparencies for air and space vehicles is referred to as the "post-bending cutting process".

The cutting to size method allows the glass sheet to be cut to the precise size required prior to heating and bending of the glass sheet. However, the cutting to the desired size method does not take into account any possible contamination that may occur on the surface of the glass sheet, which contamination may render the optical quality of the glass sheet and the subsequent formation of the transparency unacceptable.

One solution to this problem is to provide the bending iron with an improvement in its design to prevent staining of the surface of the glass sheet in contact with the bending iron. This bent iron is disclosed in USPA 13/714,494. Another solution to this problem is to reduce the temperature of the furnace and/or reduce the time period of the heating cycle during the sheet forming process for shaping the glass sheet to reduce or eliminate contamination of the surface of the glass sheet in contact with the bending iron.

As can now be appreciated by those skilled in the art, it would be advantageous to provide a method and/or apparatus for shaping glass sheets for use in aircraft and space transparencies using a method of cutting to the desired dimensions, while eliminating or reducing staining of the surface of the glass sheet that is in contact with the bending iron.

It would also be advantageous to eliminate "post-bend cutting" by providing systems and methods that allow for efficient and effective heating and/or cooling of glass sheets and/or shapes to complex shapes.

Summary of The Invention

Provided herein are methods and systems for generating complex glass sheet shapes in an efficient and automated manner. The methods and systems provided herein are improved over the prior art in that they allow for precise, tailored shapes without the use of excessive heat and the resulting increase in the likelihood of contamination. In addition, through real-time feedback, the methods and systems described herein ensure that complex shapes are realized each time.

Provided herein are methods and systems for shaping and/or bending glass sheets, comprising: preheating glass sheets on a bending iron to a preheating temperature ranging from 600 ° f to 1000 ° f; increasing the temperature of the sheet to a temperature ranging from greater than the pre-heating temperature to less than the temperature of the glass sag, such as, but not limited to, in a temperature range of 1100 ° f to 1250 ° f. Bending the glass sheet by: i.) selectively heating a portion of the glass sheet to a temperature at which at least a portion of the glass sheet sags with a convolute duct beam controlled by a computer-implemented protocol; ii.) scanning at least a portion of the glass sheet with one or more Infrared (IR) scanners at one or more points in time during or after the selective heating step, and obtaining a temperature profile in at least two dimensions for the at least a portion of the glass sheet from data obtained from the one or more IR scanners; iii.) comparing the obtained temperature distribution with a reference temperature distribution of the computer-implemented protocol using a computer-implemented process; and selectively heating the glass sheet with a convoluted tube beam controlled by a computer implemented process to match the obtained temperature profile to a reference temperature profile of the computer implemented protocol.

Additionally provided herein is a system comprising: a first furnace, also referred to herein as a glass preheating chamber/furnace, comprising an infrared heater and a temperature sensor; a second furnace, also referred to herein as a glass forming, glass bending and/or glass forming furnace, comprising an infrared heater; a convolute duct system comprising a convolute duct device or other device that can generate ultra-high frequency (e.g., at least 20GHz (gigahertz), e.g., in the range of from 20GHz to 300GHz) and high power (e.g., at least 5kW (kilowatt) electromagnetic waves in the microwave spectrum, and an optical system for controlling the shape, position, and movement of the beam of the convolute duct device to the glass sheet on the bending iron within the second furnace, and one or more Infrared (IR) imaging sensors, a conveyor system for carrying the glass sheet on the bending iron through the first furnace and the second furnace, a computer system connected to the one or more IR imaging sensors and the convolute duct system, including a processor and instructions for controlling the bending of the glass sheet in the second furnace by selective heating by the convolute duct system, the instructions including a computer implemented protocol for heating and bending the glass sheet in the second furnace, wherein the computer system obtains a temperature profile (profile) of the glass sheet from the one or more IR imaging sensors at one or more points in time during bending of the glass, compares the obtained temperature profile to a reference temperature profile of the computer-implemented protocol, and controls the convolute duct beam system to selectively heat the glass sheet to match the reference temperature profile. The system optionally contains a third furnace to controllably cool the glass sheet. The third furnace includes an IR heater, a forced cooling air convection system, and a fan. If the third furnace is not present, the first furnace will contain all of these features.

Furthermore, the invention relates to a method of operating a furnace system for shaping glass sheets for example for an aircraft transparency, the method comprising in particular:

a) placing a flat glass sheet on a bent iron having a fixed shaping rail and a shaping rail on an articulated arm (shaping arm) defined as a movable shaping rail;

b) positioning the bending iron with the glass sheet in the interior of the furnace to heat the glass sheet to shape the glass sheet on the fixed shaping rail while moving a beam of microwave energy from a gyrotron to heat a portion of the glass sheet overlying the movable shaping rail to shape the portion of the glass sheet by movement of the articulated arm;

c) obtaining and transmitting to a computer one or more thermal images of at least a portion of the glass sheet from one or more IR imaging sensors and optionally one or more shape curve images from one or more 3D imaging sensors;

d) analyzing the one or more thermal images and optionally the one or more shape curve images using a computer-implemented method and comparing the images with one or more reference thermal images and optionally one or more reference shape curve images by a computer-implemented method to determine differences between the one or more thermal images and optionally shape curve images and the reference images;

e) directing a beam of microwave energy from the gyrotron or other suitable source to heat a portion of the glass sheet to match the one or more reference thermal images and, optionally, to match the one or more reference shape curve images using a computer-implemented method based on a predetermined heat (power and speed) profile as a reference, repeating the analyzing and the comparing steps until the one or more thermal images match the one or more reference thermal images and, optionally, until the one or more shape curve images match the one or more reference shape curve images;

f) generating, via the computer-implemented method, a glass viscosity profile that allows the glass sheet to be formed or bent into a desired shape with acceptable optical quality; and

g) controllably cooling the shaped glass sheet.

Drawings

Fig. 1 is a cross-sectional view of a laminated aircraft transparency illustrating a laminated structure of the transparency.

Fig. 2 is a perspective view of a formed sheet formed in accordance with the teachings of the present invention.

Fig. 3 is a perspective view of a flat sheet that may be shaped in accordance with the teachings of the present invention to provide, among other things, the shaped sheet of fig. 2.

FIG. 4 is a perspective view of a non-limiting embodiment of a bending device that may be used in the practice of the present invention to shape a glass sheet, such as, but not limited to, the sheet of FIG. 3, among others, to the shaped sheet shown in FIG. 2.

FIG. 5 is a perspective view of a non-limiting embodiment of an oven system that can be used in the practice of the present invention to, among other things, heat and shape glass sheets (such as, but not limited to, heating and shaping the sheet of FIG. 3 to the shaped sheet shown in FIG. 2), in accordance with the teachings of the present invention.

Fig. 6 is an elevational cross-sectional view of the furnace shown in fig. 5.

Figure 7 is a perspective view of an oven door incorporating features of the present invention with portions removed for clarity that reduces heat loss between adjacent interiors of the oven systems shown in figures 5 and 6.

Fig. 8 is a perspective view of a carriage (carriage) for supporting a bending iron, such as but not limited to the bending iron shown in fig. 4, and a movable conveyor section to move the carriage to the entrance end of the furnace shown in fig. 5 and 6.

Figure 9 illustrates a microprocessor for receiving and acting on signals from sensors in accordance with the teachings of the present invention.

FIG. 10 is a convolute duct schematically partially shown in cross section that may be used in the practice of the present invention to heat selected portions of a glass sheet.

Fig. 11 is a plan view showing the path of the microwave beam of a gyrotron to selectively heat portions of a stack of one or more glass sheets.

FIG. 12 is a front cross-sectional side view of an oven system incorporating features of the present invention that can be used in the practice of the present invention to, among other things, heat and shape glass sheets.

FIG. 13 is a front plan view of an oven system incorporating features of the invention that can be used in the practice of the invention to, among other things, heat and shape glass sheets.

FIG. 14 is an elevational cross-sectional view of a furnace of the present invention that may be used in the practice of the present invention to, among other things, heat and shape glass sheets.

FIG. 15 is an elevational cross-sectional view of the furnace system of the present invention.

FIG. 16 illustrates a flow chart of a method of shaping glass sheets according to the present invention.

Detailed Description

As used herein, spatial or directional terms, such as "left", "right", "inner", "outer", "above … …", "below … …", and the like, relate to the invention as it is shown in the drawings. It is to be understood, however, that the invention can assume various alternative orientations and, accordingly, such terms are not to be considered as limiting. In addition, as used herein in the specification and claims, all numbers expressing dimensions, physical characteristics, processing parameters, quantities of ingredients, reaction conditions, and the like, are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical value should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass the beginning and ending range values and any and all subranges subsumed therein. For ranges between a minimum value of 1 and a maximum value of 10 (and including 1 and 10); that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less, e.g., 1 to 3.3, 4.7 to 7.5, 5.5 to 10, and the like. Additionally, as used herein, the term "on … …" means on, but not necessarily in contact with, a surface. For example, a first substrate "on a second substrate" does not preclude the presence of one or more other substrates of the same or different composition located between the first and second substrates.

Before discussing the present invention, it is to be understood that the invention is not limited in its application to the specifically illustrated examples, as these are merely illustrative of the general inventive concept. In addition, the terminology used herein to discuss the invention is for the purpose of description and not of limitation. Still further, like numbers refer to like elements unless otherwise indicated in the following discussion.

For purposes of the following discussion, the invention will be discussed with reference to sheet forming for aircraft transparencies. In connection with the present application, the term "glass forming" refers to the concept of glass bending and/or glass forming. These terms are used interchangeably throughout this application. As will be appreciated, the invention is not limited to the material of the sheet, for example, the sheet may be, but is not limited to, a glass sheet or a plastic sheet. In the broad practice of the invention, the sheet material can be made of any desired material having any desired characteristics. For example, the sheet may be opaque, transparent, or semi-transparent to visible light. By "opaque" is meant having a visible light transmission of 0%. By "transmissive" is meant having a visible light transmission in the range of greater than 0% to 100%. By "semi-opaque" is meant allowing electromagnetic energy (e.g., visible light) to pass through but diffusing this energy so that objects on the side opposite the viewer are not clearly visible. In a preferred practice of the invention, the sheet is a transparent glass sheet. The glass sheet may comprise a conventional soda lime silica glass, a borosilicate glass, or a lithium oxide-alumina-silica glass. The glass may be transparent glass. By "clear glass" is meant glass that is not tinted or colored. Alternatively, the glass may be dyed or otherwise colored glass. The glass may be annealed, heat treated or chemically tempered. In the practice of the present invention, the glass can be conventional float glass and can have any composition having any optical properties (e.g., any visible light transmittance, ultraviolet transmittance, infrared transmittance, and/or total solar energy transmittance values). By "float glass" is meant glass formed by a conventional float process. Examples of float glass processes are disclosed in U.S. patent nos. 4,744,809 and 6,094,942, which are incorporated herein by reference.

In one example of the invention, the glass is a transparent lithia-alumina-silica glass of the type disclosed in U.S. patent No. 8,062,749, and in another example of the invention, the glass is a transparent soda lime silica glass of the type disclosed in U.S. patent nos. 4,192,689, 5,565,388 and 7,585,801.

The glass sheets can be used in the manufacture of shaped monolithic or shaped laminated transparencies for aircraft. However, as can be appreciated, the shaped glass sheets of the present invention can be used in the manufacture of any type of transparency, such as, but not limited to, windshields, windows, backlights, sunroofs, and moon roofs (moon roof); laminated or non-laminated residential and/or commercial windows; insulating glass units, and/or transparencies for land, air, space, above water and underwater vehicles. Non-limiting examples of vehicle transparencies, residential and commercial transparencies, and aircraft transparencies and methods of making the same are found in U.S. Pat. nos. 4,820,902, 5,028,759, 6,301,858, and 8,155,816, which are hereby incorporated by reference herein.

Illustrated in fig. 1 is a cross-sectional view of an exemplary laminated aircraft windshield 20 having components that can be manufactured by the practice of the present invention. Windshield 20 includes a first glass sheet 22 secured to a vinyl interlayer or sheet 28 by a first polyurethane interlayer 30, and vinyl interlayer 28 is secured to a heatable member 32 by a second polyurethane interlayer 34. An edge member or moisture barrier 36 of the type used in the art (such as, but not limited to, silicone rubber or other flexible durable moisture resistant material) is secured to (1) the peripheral edge 38 of the windshield 20, i.e., the peripheral edge 38 of the vinyl interlayer 28; the peripheral edges of first polyurethane interlayer 30 and second polyurethane interlayer 34, and the peripheral edges of heatable member 32; (2) a marginal or marginal edge 40 of an outer surface 42 of the windshield 20, i.e., a marginal 40 of an outer surface 42 of the first glass sheet 22 of the windshield 20, and (3) a marginal or marginal edge 44 of an outer surface 46 of the windshield 20, i.e., a marginal of an outer surface 46 of the heatable member 32.

The first glass sheet 22, vinyl interlayer 28, and first polyurethane interlayer 30 form the structural or inner section of the windshield 20. The outer surface 42 of the windshield 20 faces the interior of a vehicle, such as an aircraft (not shown). The polyurethane layer 34 and the heatable member 32 form a non-structural or outer section of the windshield 20. The surface 46 of the windshield 20 faces the exterior of the aircraft. Heatable member 32 provides heat to remove fog from outer surface 46 of windshield 20 and/or to melt ice on outer surface 46 of windshield 20.

Shown in fig. 2 are two pieces of shaped glass sheets 60 and 61 shaped according to the teachings of the present invention. Each of the glass sheets 60 and 61 has curved end portions 62 and 64, and a shaped intermediate portion 66. For example, the shaped glass sheets 60 and 61 may be shaped from the flat glass sheets 68 and 69 shown in fig. 3 using the bending iron 70 shown in fig. 4. The bent iron disclosed In U.S. patent application No. 13/714,494 entitled Bending Device For Shaping Glass For Use In air In reinforcement transformers filed on 12/14/2012 may be used In the practice of the present invention. The disclosure of U.S. patent application No. 13/714,494 (hereinafter also referred to as "USPA' 494") is incorporated herein by reference in its entirety. For a detailed discussion of the bending iron 70, attention will be directed to the USPA' 494. FIG. 4 of this document corresponds to FIG. 4 of USPA' 494. As can be appreciated, the present invention is not limited to the bending iron 70, and any design of bending iron may be used in the practice of the present invention to shape one sheet or two sheets 68 and 69 (see fig. 3) simultaneously, or to shape more than two sheets into any desired shape.

Fig. 5 and 6 illustrate an exemplary furnace 74, such as, but not limited to, a furnace system, or an apparatus of the present invention for heating and shaping glass sheets, such as, but not limited to, shaped glass sheets 68 and 69. The furnace 74 includes a first chamber 76 or furnace and a second chamber 78 or furnace. First chamber 76 preheats a glass sheet (such as, but not limited to, flat glass sheet 68 or flat glass sheets 68 and 69 (see fig. 3)) supported or positioned on bending iron 70 (fig. 4), and controllably cools the shaped glass sheet (such as, but not limited to, shaped glass sheet 60 or shaped glass sheets 60 and 61 (fig. 2)) supported or positioned on bending iron 70 to anneal the shaped glass sheet. In accordance with the teachings of the present invention, the second chamber 78 selectively heats portions of the flat glass sheets 68 and 69 to shape the glass sheets 68 and 69 into a desired shape, such as but not limited to the present invention, into the shape of the shaped glass sheets 60 and 61 shown in fig. 2.

The first chamber 76 has a first opening 80 (also referred to as the "inlet 80" of the first chamber 76) and a second opening 82 (also referred to as the "outlet 82" of the first chamber 76) opposite and spaced apart from the first opening 80 (the second opening is clearly shown in fig. 6). The second chamber 78 has a first opening 84 (also referred to as the "inlet 84" of the second chamber 78 and a second opening 86 opposite and spaced from the first opening 84 of the second chamber 78 (also referred to as the "outlet 86" of the second chamber 78.) for this configuration, the flat sheets 68 and 69 supported on the bending iron 70 are moved through the first opening 80 of the first chamber 76 to the interior 88 (see FIG. 6) of the first chamber 76 to preheat the glass sheets 68 and 69, in accordance with the teachings of the present invention, the preheated glass sheets 68 and 69 are moved through the second opening 82 of the first chamber 76 and through the first opening 84 of the second chamber 78 to the interior 90 (see FIG. 6) of the second chamber 78 to controllably heat the glass sheets 68 and 69 to shape the glass sheets, the heated shaped glass sheets 60 and 61 are moved from the interior 90 of the second chamber 78 through the first opening 84 of the second chamber 78 and the second opening 82 of the first chamber 76 to the interior 88 of the first chamber 76 To controllably cool the shaped glass sheet. Thereafter, the shaped glass sheets 60 and 61 are moved from the interior 88 of the first chamber 76 through the first opening 80 of the first chamber 76.

The interior 88 of the first chamber 76 and the interior 90 of the second chamber 78 are separated from each other and from the environment outside the oven 74 by a door 92 provided at the entrance 80 of the first chamber 76, a door 94 at the entrance 84 of the second chamber 78, and a door 96 at the exit 86 of the second chamber 78. As can be appreciated, the present invention is not limited to the type of doors 92, 94, 96 provided at the inlet 80, inlet 84, and outlet 86, respectively, and any door design and/or construction may be used in the practice of the present invention. For example, the doors 92 and 96 may be similar in design and construction. In view of the foregoing, the discussion now refers to the design and construction of the door 92, and it is understood that the discussion refers to the door 96 unless otherwise indicated. Referring to FIG. 5, door 92 has sides 98 and 100 mounted in tracks 102 and 104 for reciprocal vertical movement to move up to open entrance 80 to chamber 76 and down to close entrance 80 to chamber 76, and for door 96 to move up to open opening 86 and down to close opening 86. The opening 86 of the furnace 78 is used, inter alia, for repairing the furnace 78 and for servicing the furnace 78; the interior 90 of the furnace 78 is cleaned, such as, but not limited to, removing broken glass, and for expansion of the furnace 74 discussed in detail below.

The doors 92 and 96 are moved along a reciprocating vertical path indicated by double-headed arrow 106 by a pulley arrangement 108 including a pair of wheels 110 and 112 spaced from each other and mounted on a rotating shaft 114. Cables 116, 118 have one end 120 (shown clearly for door 92) fixed to top side 121 adjacent sides 98, 100 of doors 92 and 96, respectively, and opposite ends 122, 124 of cables 116, 118 connected to air cylinders 126 (shown clearly in fig. 5 for doors 92 and 96, respectively).

For example, the doors 92 and 94 may each be made of an outer metal shell 127 having one side 128 made of steel and an opposite side 129 made of stainless steel facing the interior of their respective ones of the furnaces. The interior of housing 127 may be filled with Kaowool insulation 130 (shown clearly in fig. 5).

The shaped glass sheets 60 and 61 are moved into a first furnace and annealed. Methods of annealing glass sheets are well known in the art, see, for example, U.S. patent 7,240,519, which is hereby incorporated by reference in its entirety and no further discussion is deemed necessary. After the sheet is annealed, the gate 92 is raised and the shaped glass sheet is removed from the first furnace 76. When the formed glass sheets 60 and 61 are removed from the first furnace 76, the temperature difference between the first furnace 76 and the second furnace 78 may reach temperatures in the range of 800 ° f to 1000 ° f. More particularly, the temperature of the first furnace 76 may be as low as 200 ° f, which is the temperature at which the annealed, shaped glass sheets 60 and 61 are removed from the first furnace 76 on the movable conveyor 202, while the temperature of the second furnace 78 may be greater than 1000 ° f, which is the glass pre-heat temperature. To reduce heat loss between first and second furnaces 76, 78, respectively, door 94 may have a thermal conductivity of less than 0.80 BTU/(hr.ft. F.).

Referring to fig. 7, an exemplary door 94 includes a tube frame 94a having a stainless steel 11 gauge (gag) sheet 94b secured to a side 94c of the tube frame 94a and a stainless steel 11 gauge sheet 94d secured to a side 94e of the tube frame 94 a. Under the registered trade mark Super

A layer 133 of insulating material sold under M (having a thickness of 1 and 1/2 inches) is provided between stainless steel sheets 94b and 94d within tube frame 94 a. A layer 94g of insulating material is provided on steel sheet 94d and covered with a 0.008 to 0.010 inch thick stainless steel foil 94 h. The door 94 is mounted with stainless steel sheets 94h facing the interior of the furnace 78. The openings 94i and 94j are connected to a compressor (not shown) to move room temperature compressed air from 94a through the tubes to cool the door 94 to prevent warping of the tube frame 94a and sheets 94b and 94 d. Optionally, the peripheral edge of layer 94g is covered by foil 94hAnd (7) a cover.

The door 94 is connected to a vertically reciprocating inverted U-shaped member 136 (clearly shown in fig. 5). More particularly, the door 94 is connected by a rod 138 to a middle leg (leg)137 of the U-shaped member 136, and outer legs 139 and 140 are mounted for reciprocal vertical movement in vertical tracks 141 and 142, respectively, in any convenient manner (see FIG. 5). The U-shaped member is moved vertically up and down by an electric motor 145 (shown only in fig. 6). With the door 94 in the down position, the entrance 84 of the oven 78 is closed, and with the door 94 in the up position, the entrance 84 of the oven 78 is opened. In the upper position, as shown in fig. 6, the door 94 is moved into an enclosure 146 formed on one side (see fig. 6) by a vertical extension 148 of a metal ceiling 150 of the furnace 78, and the other side 152 of the enclosure 146 is made of a ceramic or metal wall secured between the rails 140 and 142 (see fig. 5).

The design and construction of the first furnace 76 is not limiting to the invention, and any type of furnace for heating or preheating the glass sheets to a desired temperature (e.g., a temperature below the softening or sag temperature of the flat glass sheets 68 and 69) in the manner discussed below to avoid staining of the surfaces of the glass sheets and for controllably cooling the shaped glass sheets (e.g., without limitation, the shaped glass sheets 60 and 61). More particularly, a pre-heating temperature in a range of 600 to 900 ° f is provided for the lithium soda lime glass sheet, and a pre-heating temperature in a range of 900 to 1025 ° f is provided for the soda lime silica glass sheet. The first furnace 76 may include a side wall 160 (see fig. 6) and an opposing side wall 162 (see fig. 5), a top wall or ceiling 164, and a bottom wall 166 to provide the interior 88 of the furnace 76. Short rollers 168 extend through side walls 160 and 162 to interior 88 of first furnace 76 for moving carriage 170 (see fig. 8) into interior 88 of first furnace 76 and out of interior 88 of first furnace 76, in a manner discussed below. Infrared heaters 172 are provided on interior surfaces 174 of the sidewalls 160 and 162 (only sidewall 162 is shown in fig. 6), interior surface 176 of ceiling 164, and bottom wall 166 to heat the interior 82 of the first furnace 76 to a desired temperature. In addition, the first furnace includes a thermocouple 191 to measure the heat of the furnace. Other devices besides thermocouples can be used to measure the temperature of the furnace.

The design and construction of the second furnace 78 is not limited to the present invention and any type of furnace used to heat glass sheets to a desired temperature (such as, but not limited to, heating temperatures above 900 ° f for lithium soda lime glass sheets, and heating temperatures above 1025 ° f for soda lime silica glass sheets). Heating temperatures for glass sagging are preferred, such as in the range of 1100 to 1250 ° f. For example, portions of the glass sheets to be formed, such as, but not limited to, formed glass sheets 60 and 61 (see fig. 2), are heated to their higher forming temperature using microwave energy generated by a gyrotron or any other suitable microwave energy source. Referring to fig. 5 and 6, there is shown a device 177 (e.g., a gyrotron as shown) that generates ultra-high frequency, high power electromagnetic waves, an optics box 178, and a mirror box 179 mounted on a top plate 180 of the second furnace 78. The operation of the convolute duct 177, the optics box 178 and the mirror box 179 is discussed in more detail below.

The second furnace 78 is similar in construction to the first furnace 76 and includes a side wall 181 (see fig. 6) and opposing side wall 182 (see fig. 5), a top wall or ceiling 184 and a bottom wall 186 (see fig. 6) to provide the interior 90 of the furnace 78. Short rollers 168 (see fig. 6) extend through side walls 180 and 182 into interior 90 of second furnace 78 for moving carriage 170 (see fig. 7) into interior 90 of second furnace 78 and out of interior 90 of second furnace 78, in a manner discussed below. Infrared heaters 172 may be provided on interior surfaces 188 of the sidewalls 180 and 182 (sidewalls 181 shown in fig. 6 and sidewalls 182 shown in fig. 5), interior surfaces 190 of the ceiling 184, and bottom wall 186 to heat the interior 90 of the second furnace 78 to a desired temperature. For lithium aluminosilicate glass sheets, the interior 90 of the furnace 78 is heated to a temperature in the range of 600F to 900F, and for soda-lime-silicate glass sheets, the interior 90 of the furnace 78 is heated to a temperature in the range of 900F to 1000F. In general, but not limiting to the invention, the pre-heating temperature of furnace 76 and the temperature of furnace 78 are similar with the convolutes de-energized so that the temperature in furnace 78 reached by the glass sheets in furnace 76 is maintained.

The temperatures of the interiors 88 and 90 of furnaces 76 and 78, respectively, are measured by thermocouples 191. The thermocouple 191 relays the signal to a computer microprocessor system 193 (see fig. 9). The computer microprocessor system 193 acts on the signals to determine the temperature of the interiors 88 and 90 of the furnaces 76 and 78, respectively. If the temperature of one or both of the furnace interiors is below the set temperature, a signal is forwarded along line 195 to increase the heat input to the furnace. On the other hand, if one or both of the furnace interiors 88 and 90 are too hot, a signal is forwarded along line 195 to reduce the heat input to the furnace. If the temperature inside the furnace is within the acceptable range, no action is taken.

The conveyor system for the furnace 74 includes short (stub) conveyor rolls 168 of the first furnace 76 driven by a drive arrangement 192 (see fig. 5) including shafts and motors for rotating short rolls to power the shafts (shafts and motors of drive arrangement 192 not shown), and includes short conveyor rolls 168 of the second furnace 78 driven by a drive arrangement 194 (see fig. 5) including shafts and motors for rotating short rolls to power the shafts (shafts and motors of drive arrangement 194 not shown). As is understood by those skilled in the art, conveyors using short rollers are well known in the art and no further discussion is deemed necessary.

Referring to fig. 3-8, one or more glass sheets are positioned on a bending iron (e.g., bending iron 70 shown in fig. 4) at a loading station (not shown), as desired. Two glass sheets, such as glass sheets 68 and 69 (see fig. 3), are positioned on the bending iron 70, optionally ceramic dust (not shown) can be used to prevent sticking of the formed glass sheets 60 and 61. The bending iron 70 with sheets 68 and 69 is positioned on the carriage 170 (fig. 8) and the carriage 170 is placed on the stub roller 200 of the movable conveyor 202. The mobile conveyor 202 is moved from the loading area to the oven area. Door 92 of first oven 76 is opened (see fig. 5 and 6) and movable conveyor 202 is moved into opening 80 to align stub rollers 200 of movable conveyor 202 with stub rollers 168 of first oven 76. Carriage 170 is then moved into engagement with adjacent stub rolls 168 of first furnace 76, and carriage 170 is moved by stub rolls 168 of first furnace 76 into interior 88 of furnace 76. Rotation of stub rolls 168 is prevented when carriage 170 is in a predetermined position within interior 88 of first furnace 76, which is typically the hottest position within first furnace 76. After the rotation of the stub rolls 168 is stopped, the carriage 170 with the bending iron 70 and the glass sheets 68 and 69 is held in the first furnace 76 until the glass sheets 68 and 69 reach a desired temperature, for example, in the range of 600F to 900F for lithium aluminosilicate glass and in the range of 900F to 1000F for soda-lime-silica glass. Optionally, carriage 170 may be moved slightly upstream and downstream along the conveyor travel path to circulate heated air around sheets 68 and 69 in the oven.

The temperature of the glass sheets may be monitored in any convenient manner, for example, the temperature of the glass sheets 68 and 69 is monitored by an optical pyrometer or an optical thermal scanner, such as those manufactured by Land Instruments International (Land) of Dronfield, UK. A pyrometer or thermal scanner 204 is mounted on the ceiling 164 of the first furnace 76 (see fig. 5). More particularly, a pyrometer or thermal scanner 204 (such as, but not limited to, an optical thermal scanner (manufactured by Land)) measures the temperature of the glass as carriage 170 moves toward door 94 separating ovens 76 and 78. The signal is forwarded along line 204a to the computer microprocessor system 193 (see fig. 9). If the temperature of the glass is within the acceptable pre-heating temperature range, for example, at a temperature just below the temperature at which the glass sags, the carriage 170 is moved into the furnace 78. If the glass is not within the acceptable forming temperature range, carriage 170 is not moved into forming furnace 78 and appropriate action is taken, such as, but not limited to, increasing the temperature of furnace 76 if the glass temperature is too low, or decreasing the temperature of furnace 76 if the glass temperature is too high.

After the glass sheets 68 and 69 reach the desired temperature, the door 94 of the second furnace 78 is opened, and the stub rollers 168 of the first and second furnaces 76 and 78 are energized to move the carriage 170 through the opening 84 of the second furnace 78 to the designated forming position in the interior 90 of the second furnace 78 (discussed in detail below). Door 94 of second oven 78 may be closed at any time after carriage 170 has passed into the interior of second oven 78. After carriage 170 with glass sheets 68 and 69 and bending iron 70 is positioned in the forming position indicated in interior 88 of second furnace 78 or carriage 170 has passed over (clear) door 94, as discussed below, door 94 is closed and the forming method of the present invention using convolute tube 177 discussed in detail below is practiced.

After the glass sheets 68 and 69 are formed, the convolute duct 177 is de-energized or out of service (deactivated) and the door 94 of the second furnace 78 is opened. The stub rollers 168 of the first and second ovens 76 and 78, respectively, are energized to move the carriage 170 with the shaped sheets 60 and 61 from the interior 90 of the second oven through the opening 84 of the second oven 78 and into the interior 88 of the first oven 74. After carriage 170 is moved into interior 88 of first furnace 76, door 94 of second furnace 78 is closed. The shaped glass sheet is controllably cooled to anneal the sheet. When the annealing method is completed, door 92 of first furnace 76 is opened and movable conveyor 202 (see fig. 8) is moved into opening 80 of first furnace 76 to align with stub rolls 168 of first furnace 76. Stub rollers 168 of the first furnace are energized to move carriage 170 out of interior 88 of first furnace 76 onto moveable conveyor 202. The movable conveyor with carriage 170 is moved to a discharge station (not shown) and the formed glass sheet is removed from the bending iron 70 in any usual manner.

The discussion now involves heating portions of one or more glass sheets to their bending or forming temperature using a convolute duct 177 (see fig. 5, 6, and 10, as needed). Notably, the present application describes the use of a convolute duct system. The convolute duct is a non-limiting example, and any suitable system can be used to locally heat (spot-heat) the glass sheet through the thickness of the sheet, including the exterior surface and interior of the sheet. Suitable systems include systems that generate ultra-high frequency (e.g., at least 20GHz (gigahertz)) and high power (e.g., at least 5kW (kilowatts)) electromagnetic waves within the microwave spectrum. Such as, for example, a klystron or traveling wave tube, but the output frequency and wattage of these devices is less than that of a gyrotron system. As previously discussed, glass for aircraft transparencies is manufactured using a post-bending cutting method to remove portions of the glass sheet having optical distortion (e.g., without limitation, resulting from the long period of time required for the glass sheet to rest on a bending iron to reach the desired temperature for bending). For example, it is desirable to render overheating of the surface of the glass sheet using conventional methods so as to achieve the desired bending of the glass unnecessary through the use of convoluted tubes or other sources of high energy electromagnetic radiation. The use of a convolute duct can reduce the glass sheet surface temperature by 30% to 40% to internally heat selected portions of the glass sheet to their bending or forming temperature. As can now be appreciated, it is desirable to significantly reduce glass smearing by reducing the need for overheating of the glass surface by conventional methods of adjusting the furnace temperature, and the resulting elimination of overheating of the bending iron and/or forming rail on which the glass sheet sits, and to greatly facilitate bending of glass sheets for use in, for example, aircraft transparencies using methods of cutting to the desired dimensions instead of post-bending cutting methods.

Gyrotrons are high power linear beam vacuum tubes capable of generating high power, high frequency electromagnetic radiation near the edge of the infrared terahertz (THz) spectrum. Its operation is based on stimulated cyclotron radiation of electrons oscillating in a strong magnetic field (e.g. as provided by a superconducting magnet). Any suitable microwave generator capable of generating high power, high frequency electromagnetic waves, such as a microwave generator having an output frequency ranging from 20GHz to 300GHz and having a power output of at least 5kW, would be suitable. A schematic diagram indicating various parts of the convolute duct 177 is shown in fig. 10. In general, and without limiting the invention, in operation of the gyrotron 177, electrons emitted by the cathode 206 surrounded by the gun coil magnet 208 are accelerated in the strong magnetic field of the superconducting magnet 210. As the electron beam 212 travels through the strong magnetic field 210, the electrons begin to spin at a particular frequency given by the strength of the magnetic field. In the cavity 214 located at the position with the highest magnetic field strength, the THz radiation is strongly amplified. Mode converter 216 is used to form a free gaussian beam 217 that exits gyrotron 177 through window 222 and couples to waveguide 224. The operation of convolutes is well known in the art and no further discussion is deemed necessary. Convolute tubes are available from Gyrotron Technology, inc.

With continued reference to fig. 10, the free gaussian beam 217 passes through the waveguide 224 to the optical box 178. The optics box 178 has a mirror (not shown) configured as known in the art to collimate the free gaussian beam 217 into a single beam 225 and to control the size, e.g., diameter, of the beam 225. The collimated beam 225 exits the optics box 178 via the waveguide 226 and passes into the mirror box 179. Mirror box 179 has one or more movable mirrors 228 (one mirror is shown in phantom in fig. 10) to move beam 225 through a predetermined area defined by cone 230 (see fig. 6 and 10). In fig. 10, beam 225 moving through cone 230 is incident on a flat glass sheet, e.g., flat glass sheets 68 and 69 positioned on a bending iron, e.g., bending iron 70 (fig. 4). The sheets 68 and 69 and the bent iron 70 are shown in block diagram form in fig. 10.

The discussion now relates to heating the portion 232 of the flat glass sheets 68 and 69 (see fig. 3) shaped by the articulated arm 234 of the bending iron 70 (fig. 4) and the portion 236 shaped by the fixed shaping rail 238 of the bending iron 70 using the beam 225 from the convolute tube 177. Generally, the flat glass sheets 68 and 69 positioned on the contoured rails 239 of the articulated arm 234 maintain the articulated arm 234 in a lower position (as shown in fig. 4), which maintains the weight 240 in an upper position. When the portions 232 of the glass sheets 68 and 69 that overlie the shaping rails 239 of the articulated arms 234 of the bending iron 70 are heated to the shaping temperature of the glass sheets 68 and 69, the weights 240 move downward, moving the articulated arms 234 upward to shape the portions 232 of the glass sheets 68 and 69 into the shapes 232 shown on the sheets 60 and 61 in fig. 2. For a more detailed discussion of the operation of articulated arm 234 of bending iron 70, reference should be made to USPA' 494. Portions 236 of the flat glass sheets 68 and 69 are shaped by the fixed shaping rails 238 to the portions 236 of the shaped glass sheets 60 and 61. In the practice of the invention, portions 232 and 236 of glass sheet 62 are heated by beam 225 from convolute tube 177 to rapidly reach a bending temperature in the range of 1000F to 1100F for lithium aluminosilicate glasses and 1100F to 1200F for soda-lime-silicate glasses.

The microprocessor or computer system 193 (fig. 9) is programmed (e.g., without limitation, with signals sent along the electrical wires 239) to control the operation of the mirrors of the optics box 178 to set the size of the beam 225 incident on the portion of the glass sheet being shaped, to control the movement of the mirrors 228 of the mirror box 179 to control the direction and speed of movement of the beam 225 in the zone 230 (see fig. 10), and to control the energy of the beam 225 by altering the anode voltage, the magnetic field applied to the system of the convolute tube, and/or the strength of the voltage. As needed, referring to fig. 9 and 10, the mirror 228 operated by the microprocessor 193 moves the beam 225 along a predetermined path 244 on a surface 246 of the top glass sheet (e.g., the top glass sheet 68 facing the mirror box 179). The energy beam 225 heats the glass sheet to its softening temperature for the glass sheet as it moves along a path 244 in the region of the sheet designated by the numeral 236 to take the shape of a fixed shaping rail 238 (see fig. 4). The energy beam 225 heats the glass sheet to its forming temperature as it moves along a path 244 in the region of the sheet designated by the numeral 232 (see fig. 11), at which time the articulated arm 234 of the bending iron 70 forms the sheet in the region 232. Mounted through the roof 180 of the furnace 78 on each side of the mirror box 177 are pyrometers 250 (see FIG. 6) to monitor the temperature of the glass. Pyrometer 250 is connected by wire 251 to microprocessor or computer 193 to send signals to microprocessor 193, and microprocessor relays signals along wire 239 to maintain the temperature of selected portions of the glass within a desired temperature range by altering the speed of beam 225 along path 244 and/or by altering the energy of the beam, as discussed above. More particularly, decreasing the velocity of the beam 225 increases the temperature of the glass and vice versa, and increasing the anode voltage, magnetic field, and/or applied voltage increases the temperature of the glass and vice versa.

The following are examples of the invention for shaping glass sheets for use in the manufacture of aircraft transparencies. Flat glass sheets 68 and 69 (fig. 3) are positioned on a bending iron 70 (fig. 4). The bending iron 70 is placed in a carriage 170 (fig. 7) and the carriage is placed on a stub roller 200 of a conveyor 202. Carriage 170 with bending iron 70 and glass sheets 68 and 69 is moved by stub rolls 168 of first furnace 76 into interior 88 of first furnace 76 (fig. 6). The glass sheets in the closed interior of the first furnace 76 are heated to a temperature below the softening point temperature of the glass. Thereafter, carriage 170 with heated glass sheets 68 and 69 is moved by stub rolls 168 of first furnace 76 and second furnace 78 into interior 90 of second furnace 78 and positioned within the area of cone 230 (see fig. 6 and 10).

The temperature of the interior 90 of the second furnace 78 is substantially the same temperature as the interior 88 of the first furnace 76, i.e., a temperature below the forming temperature of the glass sheets on the bending iron 70. At this temperature, the glass sheet positioned on the bending iron is not yet formed. After carriage 170 positions the sheet within cone 230, gyrotron 177, optics box 178, and mirror box 179 are energized to move beam 225 along scan path 244 (see FIG. 10). As the beam 225 moves along the scan path 244, the convolute tube 177 is in an operational mode. The energy beam 225 heats the glass sheet to its softening temperature for the glass sheet as it moves along a path 244 in the region of the sheet designated by the numeral 236 to take the shape of a fixed shaping rail 238 (see fig. 4). The energy beam 225 heats the glass sheet to its forming temperature as it moves along a path 244 in the region of the sheet designated by the numeral 232 (see fig. 9), at which time the articulated arm 234 of the bending iron 70 forms the sheet in the region 232. The beam is in the operating mode to heat the section 232 of the sheet 68 as the beam moves along the section 250 of the scan path. As the segment or portion 232 of sheet 68 is heated, the segment of sheet softens and the weight 240 of the bent iron moves the articulation rail 238 upward to shape the portion 232 of sheet 268. After shaping the sheet, power to the convolute duct 177 is reduced or disconnected to place the convolute duct and beam 225 in an idle mode.

The stub rolls 168 of the second oven 78 and the first oven 76 move the carriage 170 with the shaped sheets 60 and 61, respectively, from the interior 90 of the second oven 78 into the interior 88 of the first oven 76. The shaped sheet in the first furnace 76 is controllably cooled to anneal the shaped glass sheet. Thereafter, carriage 170 is moved by stub rolls 168 of first furnace 76 onto movable conveyor 202, and the movable conveyor is moved to a discharge area (not shown).

As can now be appreciated, when doors 92 and 94 (see fig. 5 and 6) are opened, care is taken to ensure that carriage 170 (see fig. 9) moves into ovens 76 and 78, and between ovens 76 and 78. As a safety feature, tracking sensors 300, 302 and 304 are used to track the position of carriage 170 as it moves through ovens 76 and 78. Although not limiting to the invention, each of tracking sensors 300, 302, and 304 includes a continuous beam of light generated, such as, but not limited to, a laser-generated beam incident on a detector. As carriage 170 moves through the continuous beam, the beam is directed away from the detector, and the detector sends a signal along cable 306 to microprocessor 193 indicating that the beam is not incident on the detector. Computer microprocessor system 193 sends a signal along wire 308 to open or close door 92 or door 94. By way of illustration and not limitation, the tracking detector 300 is positioned in the oven 76 spaced from the door 92 a distance greater than the width of the carriage 170. The travel of the light beam is transverse to the path of travel of carriage 170. As carriage 170 moves into furnace 76, carriage 170 interrupts the light beam by directing the light beam away from the detector of sensor 300. The detector of the tracking sensor 300 sends a signal along the cable 306 to the microprocessor 193 indicating that the beam of light has not struck the detector, and the microprocessor sends a signal along the cable 308 to energize the motor 124 (see fig. 5) to close the door 92.

Optionally, as carriage 170 moves through furnace 76, glass sheets 68 and 69 are heated, or glass sheets 68 and 69 move to the center of the furnace and heating of the sheets is stopped. After heating the glass sheets, the glass sheets 68 and 69 (see FIG. 3) and carriage 170 are moved toward the door 94 of the separation furnaces 76 and 78. The carriage interrupts the light beam from the sensor 302 and relays a signal along the cable 308 to the computer microprocessor system 193 to energize the motor 145 to raise the door 94. The system is timed so that carriage 193 can move continuously from first furnace 76 into second furnace 78 without any interference. Carriage 170 moves into furnace 78 and, after fully entering furnace 78, interrupts the light beam from sensor 304. Sensor 304 relays a signal along cable 308 to microprocessor 193 to close door 94; microprocessor 193 relays a signal along cable 308 to energize the motor to close door 94. The carriage 170 moves into the forming position and the conveyor stops. As can be appreciated, the distance of the beam from the forming position to the detector 304 and the speed of the carriage 170 are known, and in this way, the movement of the conveyor can be stopped when the carriage and glass sheet are in the forming position. In another example of the present invention, the carriage 170 is positioned in the forming position using a tracking sensor 309 (shown in phantom and only in fig. 6). When carriage 170 displaces or interrupts the light beam of tracking sensor 309, a signal is relayed (e.g., along cable 306) to computer microprocessor system 193 and the computer microprocessor system relays a signal (e.g., along cable 308) to stop the rotation of the stub roll to position carriage 170 and the glass sheet in the forming position. Optionally, the timing of the sensor 309 and computer microprocessor system can be used to position the carriage relative to the beam.

After the glass sheets 68 and 69 are shaped, the carriage 170 and the shaped sheets are removed from the furnace 74. More particularly and not limiting to the invention, carriage 170 deflects or interrupts the light beam from sensor 304 to open door 94, causes the light beam from detector 302 to interrupt to close door 94, and causes the light beam from detector 300 to interrupt to open door 92.

As can be appreciated, the present invention is not limited to the design of the furnace 74, and the present invention contemplates practicing the present invention with any type of furnace, such as, but not limited to, the furnaces shown in fig. 5 and 6 discussed above and fig. 12-15 discussed below. More particularly, shown in fig. 12 is a furnace 258 having the first and second furnaces 76, 78, respectively, discussed above, and a furnace 260 attached to the second opening 86 (see fig. 5, 6, and 12) of the second furnace 78. The oven 260 is similar to (if not identical to) the first oven 76. With the furnace configuration shown in fig. 12, the carriage 170 with the bending iron 70 (with sheets 68 and 69) may move along the path indicated by arrow 270, through the furnace 76 to preheat the glass sheets 68 and 69, through the furnace 78 to shape the glass sheet 68, and through the furnace 260 to anneal the shaped glass sheets 60 and 61 (as discussed above for the first furnace 76). In a second example of the present invention, furnace 258 may shape glass sheets 68 and 69 using first furnace 76 and second furnace 78, respectively, by moving carriage 170 with bending iron 70 and glass sheets 68 and 69 along a reciprocating path indicated by arrow 272, and shaping a second set of glass sheets 68 and 69 using furnaces 78 and 260 in a similar manner to furnaces 76 and 78, and moving the second set of glass sheets along a reciprocating path indicated by arrow 274, as discussed above.

Referring to fig. 13, another example of a furnace designated by the numeral 261 is shown. Furnace 261 includes furnaces 76, 78, and 260 (see fig. 12) and furnaces 262 and 264. Forming furnace 78 is between furnaces 262 and 264. The glass processed using the furnace 261 has travel paths 270 and 278 in the horizontal direction and travel paths 270a and 278a in the vertical direction, as shown in fig. 13; reciprocating paths 272 and 274, and reciprocating paths 275 and 276 in the vertical direction, as shown in fig. 13. The glass sheets moving along the travel path 276 may be moved into and out of the furnaces 262 and 78 and the furnaces 264 and 78. As can be appreciated, the conveyor system for the oven 78 shown in fig. 13 is adjustable or provided with a two-tier conveyor system to move the carriage along path 278 through the ovens 262, 78, and 262, and to move the carriage along path 278a through the ovens 76, 78, and 260.

Referring to FIG. 14, there is shown still another non-limiting embodiment of the oven of the present invention designated by the numeral 280. The furnace 280 includes a first tunnel furnace 282 to preheat the flat glass sheets 68 and 69 as they move in the direction of arrow 284. Glass sheets 68 and 69 may be positioned on the bending iron 70, or as discussed above, the bending iron 70 may be positioned in the carriage 170. The forming furnace 286 positioned at the outlet end 287 of the tunnel furnace 282 may have any number of convolutes to provide any number of forming zones, such as one forming zone 230 shown in solid lines, or two forming zones 231 shown in phantom, or three forming zones 231 shown in solid lines 230 and phantom. A second tunnel furnace 288 is connected to the outlet end 289 of the forming furnace 286 to controllably cool the formed glass sheets 60 and 61. Also depicted are thermal sensors 324 and position sensors 320 and 321.

The thermal sensor 324 is any sensor or scanning device (such as an IR scanner or IR imaging sensor) capable of generating data indicative of the temperature of one or more portions of the glass sheet, such as a Charge Coupled Device (CCD), infrared laser sensor device, thermal imaging device, or thermal scanner, as is widely known and commercially available. A representation of the glass sheet can be generated by computer-implemented processing, by compiling (assembling) data obtained from the thermal sensors, such as raw CCD data, and generating a two-dimensional or three-dimensional temperature profile of at least a portion of the glass sheet. As indicated below, thermal data is obtained from a thermal sensor and a temperature profile generated from the data is compared in a computer-implemented process with a reference temperature profile, and any difference between the generated temperature profile and the reference temperature profile is a trigger that selectively heats the glass sheet through the convolute tube to match the temperature profile of the glass sheet with the reference temperature profile. The computer-implemented processes that perform these tasks, as well as any tasks indicated herein, are readily designed and implemented by those of ordinary skill in the art of computer imaging and process control. One or more thermal sensors may be used, and more than one different type of sensor may be used to obtain an accurate and useful real-time thermal profile of the glass sheet.

The position sensors 320 and 321 are any device capable of generating data representing the shape of the glass sheets. Non-limiting examples of position sensors are CCD and laser sensors, as are widely known and commercially available. The data is obtained from the position sensors 320 and 321 and compiled by computer implemented processing to generate a shape curve for the glass sheets in the furnace 78. As indicated below, position data is obtained from a position sensor, and a shape curve generated from the data is compared to a reference shape curve in a computer-implemented process, and any difference between the generated shape curve and the reference shape curve is a trigger that selectively heats the glass sheet through a convolute tube to match the shape curve of the glass sheet to the reference shape curve. Any number of position sensors may be used as long as meaningful data is obtained relating to the real-time shape curve of the glass sheet during the bending process. Also, more than one type of position sensor may be used to obtain the resulting shape curve in order to obtain an accurate and useful real-time representation of the glass sheet during the bending process. For example, two CCDs may be used to generate a solid shape curve for the glass sheet, while one or more laser distance sensors are used to determine the spatial position or orientation of one or more points on the surface of the glass sheet, in order to best determine the degree of bending of the glass sheet at any time.

The obtaining and processing of heat and shape data and the use of those data to generate temperature and shape curves may be repeated one or more times during the bending process, for example, at intervals ranging from every 0.0001 second to every 60 seconds, including every 0.0001 second, 0.001 second, 0.01 second, 0.1 second, 0.5 second, 1 second, 2 seconds, 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds, and 60 seconds, including any increment therebetween. Even shorter time intervals are contemplated and are limited only by the throughput (e.g., processing power) of the computer system. The convolute duct system may not be able to respond as quickly to the computer system as the computer system may analyze the data, so the scan interval may be set based on the response of the convolute duct system. Even so, within the limits of the associated hardware, scanning and analysis of the thermal and optionally spatial profiles can be performed at a faster rate than the control of the gyrotron.

As will be appreciated by those skilled in the art, the inlet opening 290 of the first tunnel oven 282 and the outlet opening 292 of the second tunnel oven 288 may remain open during the formation of the sheet. The doors into and out of the forming furnace 286 are preferably opened to move the glass sheet to be formed into and out of the furnace 288, and during the forming of the glass sheet in the forming furnace 286, the doors (see fig. 5 and 6) are closed to minimize heat loss during the sheet forming process. Optionally and within the scope of the present invention, the doors of the tunnel furnace may be kept open for continuous movement of the glass sheets through the tunnel furnace to shape the glass sheets.

Fig. 15 schematically shows an example of the furnace system of fig. 6. Details of fig. 6 that are unnecessary to show the operational and structural differences between the furnace of fig. 6 and the furnace of fig. 15 are omitted for ease of visualization, but are included in fig. 15. As in fig. 6, the furnace system 74 of fig. 15 includes a first chamber 76, a second chamber 78, and a door 94 supported by a U-shaped member 136. The first chamber 76 preheats the glass sheet carried on the conveyor 202 to a temperature in the range of 900 ° f to 1000 ° f via the use of infrared heaters, although other suitable preheating temperatures may be utilized depending on the material of the glass sheet. In use, the glass sheets are supported or positioned on a bending iron (not shown, but as depicted and described herein). The second chamber 78, also referred to herein as a forming chamber, selectively heats portions of the flat glass sheet to achieve a desired shape of the glass sheet. The infrared heater of the second chamber 78 maintains the temperature of the chamber to about 1000-1100 ° f, or any temperature just below the forming or sag temperature of the glass sheet. Certain portions of the glass sheet are selectively heated in the second chamber 78 by a cyclotron beam system (including a gyrotron 177, an optics box 178, and a mirror box 179). A benefit of the use of the high energy microwave system described herein is that the microwave source (e.g., a gyrotron) heats the glass sheet internally and at a precise location on the glass sheet. On the other hand, conventional infrared heaters only heat the glass surface and, via thermal conduction, energy is transferred into the glass. As a result, under conventional infrared heating, the glass surface is significantly hotter than the internal glass temperature, thus increasing the likelihood of undesirable manufacturing conditions for glass bending. By "selective heating" is meant that the cyclotron beam system involves heating a particular area, portion, or location of the glass to cause the glass sheet to sag to produce a desired shape. Once the glass sheet is shaped to the desired specification, the glass sheet is controllably cooled. In the illustrated embodiment, the first chamber 76 also serves as a cooling chamber for annealing the glass sheet, such that once the glass sheet is shaped in the second chamber 78, it is returned to the first chamber 76 where it is cooled in a controlled manner. The furnace system 74 may include a third chamber on the opposite side of the second chamber 78 from the first chamber 76, and the conveyor 202 sequentially passes glass from the first chamber 76, through the second chamber 78, and to a third furnace. The furnace system 280 of fig. 14 depicts a similar orientation. The inclusion of the third furnace simplifies the process in that the glass sheets can be moved through the system in a linear fashion. The third furnace is a cooling chamber capable of controllably cooling the shaped glass sheet to anneal the shaped glass sheet. The third furnace may be modified so that the shaped glass sheet may be thermally tempered or thermally strengthened.

An infrared sensor 324 may be provided in addition to, or in place of, the pyrometer 204 illustrated in FIG. 6. The pyrometers 204 and/or the infrared sensors 324 monitor the temperature of the entire sheet of glass and/or specific portions of the glass. As used herein, a "portion" is an amount that is less than all or 100% of an object, and can be a point, line, area, region, etc. on and/or in an object (such as a glass sheet).

The methods and systems described herein rely in one aspect on a computer, such as similar to but not limited to microprocessor 193, at least for monitoring and controlling the progress of heating and bending of the glass sheets described herein. The computer or computer system may be in any physical form, such as a Personal Computer (PC), credit card computer, Personal Digital Assistant (PDA), smart phone, tablet, workstation, server, mainframe/enterprise server, etc. The terms computer, computer system or microprocessor system or computer microprocessor system may be used interchangeably herein. The computer contains one or more processors, e.g., Central Processing Units (CPUs), that execute instructions for the computer. The computer also includes a memory (memory) such as a RAM and a ROM (e.g., storing UEFI or BIOS) coupled to the processor by any suitable structure, such as a system bus. The computer also includes non-transitory storage (storage) for storing programming and data in the form of computer readable medium(s) such as hard disk drives, solid state disk drives (SSDs), optical drives, tape drives, flash memory (e.g., non-volatile computer storage chips), cartridge drives (drives), and control elements for loading new software. The computer system as described herein is not limited by any topology or relative location of various hardware elements, recognizing the varying physical and virtual structures that are commonly used by those of ordinary skill in the art in implementing computer systems.

Data, protocols, controllers, software, programs, etc. may be stored locally in the computer, for example, in a hard drive or SSD; stored within a local or wide area network, e.g., in the form of a server, network associated drive (NAS); or stored remotely such that the connection is made via an internet connection (e.g., via remote access). Data, such as images, temperature profiles, or shape profiles generated or used by the methods and systems described herein, may be organized on a computer-readable medium in a database, which is an organized collection of data for one or more purposes. Other exemplary hardware forming elements of a typical computer include input/output devices/ports such as, but not limited to: universal Serial Bus (USB), SATA, eSATA, SCSI, Thunderbolt interface (Thunderbolt), display (e.g., DVI or HDMI), and ethernet ports (as are widely known), and a graphics adapter, which may be an integral part of the CPU, a subsystem of the motherboard, or as a separate hardware device (such as a graphics card). Wireless communication hardware and software such as Wi-Fi (IEEE 802.11), Bluetooth, ZigBee, etc. may also be included in the computer. The components of the computer need not be housed within the same housing, but may be connected to the main computer housing via any suitable port/bus. In a typical computer, at least the CPU, memory (ROM and RAM), input/output functionality, and often a hard disk drive or SSD, are housed together with a display adapter and connected by a high performance bus of any available topology.

A computer with storage and memory capabilities may include controller aspects that allow for the design, storage, and execution of instructions that may be executed for independently or collectively directing the computer system to interact and operate as programmed, referred to herein as "programming instructions". In the context of computing, broadly speaking, a computer-implemented process (i.e., a program) refers to any computer-implemented activity that produces a result, such as the implementation of a mathematical or logical formula or operation, an algorithm, or the like.

One example of a controller is a software application (e.g., a basic input/output system (BIOS), Unified Extensible Firmware Interface (UEFI), an operating system, a browser application, a client application, a server application, a proxy application, an online service provider application, and/or a private network application) installed on a computer system for directing the execution of instructions. In one example, the controller is based on WINDOWS^TMThe operating system of (1). By using any suitable computer language (e.g., C \ C + +, UNIX SHELL SCRIPT, PERL, JAVA^TMJAVASCRIPT, HTML/DHTML/XML, FLASH, WINDOWS NT, UNIX/LINUX, APACHE, RDBMS including ORACLE, INFORMIX, and MySQL) and/or object-oriented technology implementation controllers.

The controller may be embodied permanently or temporarily in any type of machine, component, physical or virtual device, storage medium, or propagated signal capable of communicating instructions to a computer system. In particular, the controller (e.g., software application, and/or computer program) may be stored on any suitable computer readable medium (e.g., a disk, a device, or a propagated signal) readable by a computer system such that the functions described herein are performed if the storage medium is read by the computer system.

The computer contains "protocols," which are instructions and data that control, for example, the bending process for the glass sheets. Various modeling techniques may be used to develop the protocol, and may be implemented as part of a computer-implemented protocol. The modeling techniques include scientific and mathematical models specific to the glass bending process that enable the determination of the required temperatures at different stages of the process necessary to achieve a high quality final glass sheet. Such as the preheat temperature at the exit of the first furnace, the glass forming/bending temperature profile in the glass forming furnace, the exit glass temperature once the forming process is complete, and the glass annealing temperature. The protocol controlled cyclotron beam system establishes a heating profile to achieve a particular shape for the glass sheet. The gyrotron beam may be steered in various ways, such as altering the path, speed, width, shape, frequency, dwell time or intensity/energy (e.g., kilowatts, kW) at a location (on the glass sheet). In one embodiment, the beam width, beam shape, intensity/energy, and frequency are constant, but the position, path, speed, and/or dwell time at a location of the convolute duct beam is altered to provide a desired heating profile on the sheet. In another example, the power of the convolute duct beam can be manipulated as it is moving across the surface of the glass sheet at a constant speed to produce the desired thermal profile. In another example, a technician may change both power and beam speed to achieve the same effect. The protocol includes instructions for controlling at least any or all of the possible parameters of the convolute tube beam, such as position, path, intensity/energy, velocity, beam shape, beam diameter, and output frequency, which may be controlled by the convolute tube unit or the post-convolute tube optics. Thus, the protocol controls the heat profile and/or heat distribution on the glass sheet for obtaining the desired shape and size of the glass sheet. Included as part of the protocol, the computer receives and processes real-time data from the thermal and position sensors (particularly, thermal sensors, and optionally, position sensors). The computer then generates a temperature profile, and optionally a shape profile, from the real-time data. The temperature profile and shape profile are merely representations in a computer that can be compared to reference temperature and shape profiles stored in association with a bending protocol. The computer system compares the generated curve to a reference curve to determine differences between the generated curve and the reference curve at one or more locations on the glass sheet, and if there are differences and one or more locations on the glass sheet require heating to match the temperature and shape of the glass sheet to the reference curve, the computer controls one or more parameters of the convolute duct beam to selectively heat a portion of the glass sheet to correct for those differences. In addition to the above, optionally, the computer receives additional temperature data from one or more temperature sensors (such as thermocouples or IR scanners of one or more chambers and/or ovens of the system according to any example described herein) and acts as a thermostat, monitoring and adjusting the ambient temperature of the chamber, e.g., by adjusting the output of IR heaters, blowers, etc. utilized in the system. For example, in one aspect, a thermocouple (e.g., as shown in fig. 6) detects the temperature of the second furnace 78, as shown in fig. 15. If the second furnace 78 is not at the desired temperature, the computer (using, for example, a computer implemented process as described above) compares the actual ambient temperature of the second furnace 78 with the stored reference ambient temperature for the second furnace 78 and automatically adjusts the heat of the second furnace 78 to reach the stored reference ambient temperature. By "ambient temperature" with reference to the furnace described herein is meant the temperature of the atmosphere at one or more points within the furnace, and not the temperature of the glass sheet.

In another aspect, the thermal sensor 324 is an IR laser sensor that captures IR images of the glass sheet being bent that are sent to a computer, compares the captured images to reference images stored as part of the glass bending protocol for the particular glass sheet, and if a location on the glass is at a temperature that is lower than the temperature of the same location in the images stored as part of the glass bending protocol, directs the gyrotron beam to heat the location until the temperature of the location matches the reference temperature of the images stored as part of the glass bending protocol. As used herein, a protocol for producing a particular shape from a glass sheet contains one or more reference temperature profiles and shape profiles for the particular shape and glass sheet at one or more points in time during a bending process.

Fig. 15 also depicts an optional position sensor 320. Suitable light sources may also be used to provide illumination of the glass sheet to the extent necessary to permit imaging, but for imaging purposes, the heated glass typically emits sufficient light. The position sensor includes a single unit or multiple units that allow for real-time image capture or capture of data indicative of the spatial position of one or more locations on the glass sheet. Non-limiting examples are position sensors available from Rockwell Automation (Allen Bradly), for example 42CM 18mm LaserSight or 42EF LaserSight RightSight are suitable position sensors. The position sensor may be an imaging sensor, such as one or more CCD and/or laser sensor devices housed together or at separate locations within the chamber 78. The CCD and/or laser sensor device outputs a 2D image that is processed within a computer or device. The image may be used in its 2D form, or may be processed by a computer to form a 3D image to generate a curve of the glass sheet indicative of the real-time spatial position and shape of any portion or point on the glass sheet, and then the 2D curve is compared to a reference curve associated with the protocol, and heating is adjusted by the convoluted tube beam to match the shape curve of the glass sheet to the reference curve. A wide variety of position, distance, measurement, displacement, curve, 2D and 3D sensors (e.g., laser sensors) are commercially available, such as, without limitation, Omron Automation & Safety from Rockwell Automation (Allen Bradly), Emerson Electric of st. In any case, a position sensor is connected to the computer, and the data is optionally coordinated with the IR data described above, obtained from the position sensor, and this data is compared to reference data associated with the protocol used to bend the particular glass sheet, and the temperature of any portion of the glass sheet can be adjusted using the convoluted tube beam.

As shown in fig. 15, two position sensors 320, 321 are shown. A composite 3D image or collection of images of the glass sheet at any given point in time may be generated by computer-implemented processing to evaluate the shape of the glass sheet at any point in time. The computer system generated 3D image, composite image or collection of images and/or portions thereof of the glass sheet may be compared to the values of the reference shape curve of the protocol and if there is a deviation from the desired shape stored in the protocol, the computer system controls the ambient temperature of the convolute duct 177 and/or the second furnace 78, optionally in conjunction with infrared image data from the 2D infrared imaging sensor 324, to heat the glass sheet or portions thereof to shape the glass sheet to meet the requirements of the recipe. FIG. 16 provides a flow diagram illustrating a non-limiting embodiment of the methods described herein using two or three chambers as discussed with respect to FIG. 15.

The gyrotron beam may be steered in various ways, such as altering the path, velocity, width, frequency, dwell time or energy intensity or power at a location of the gyrotron beam. In one example, the beam width, energy, and frequency are constant, but the position, path, speed, and/or dwell time at a location of the convolute duct beam is altered to provide a desired heating profile on the sheet.

"temperature profile" or "temperature profile" refers to the temperature of any one or more portions of a particular glass sheet at any one or more points in time during the method of heating to bend and cool the glass sheet. As used herein, "reference temperature profile" refers to a temperature profile for any particular glass sheet stored locally on a computer system or remotely in association with a protocol for bending that particular glass sheet. The reference temperature profile is created or developed by any method, such as by a formula and/or trial and error, to produce a particular shape for a particular glass sheet. The reference temperature profile used to produce the desired shape from the glass sheet will depend on a number of factors, including among others the following: composition of the glass sheet, desired shape and functionality of the iron bend. By using the predetermined temperature profile as a reference, and finally manipulating the convolute tube system to selectively heat the glass sheets, a uniform glass viscosity distribution is produced not only inside the glass but also throughout the glass. This uniform distribution of glass viscosity eliminates overheating of the glass surface and, as a result, the glass sheet will be formed or bent into the desired shape with satisfactory optical quality.

The term "shape curve" refers to the 2D or 3D shape of a glass sheet at any one or more points in time during the method of heating, bending, and cooling the glass sheet. "reference shape curve" refers to a shape curve for any particular glass sheet stored locally on a computer system or remotely for any point in time in a glass forming process that is associated with a protocol for bending that particular glass sheet. The reference shape protocol is created or developed by any method, such as by a formula and/or trial and error, to produce a particular shape for a particular glass sheet. As with the predetermined heat distribution, the reference shape curve for producing the desired shape from the glass sheet will depend on a number of factors, including among others: composition of the glass sheet, desired shape and functionality of the iron bend.

The invention further encompasses the use of safety devices to limit or prevent injury to personnel operating the device, and/or to prevent or limit damage to the device. For example and without limitation to this discussion, the apparatus includes an arc detector 330. An arc detector 330 is mounted in the furnace 78 and contains a photocell connected to the microprocessor 193 by cable 306. As is known in the art, arcing is the action of ionized matter, such as, but not limited to, air-borne pockets of dust, and the appearance of clusters of light. The arcing phenomenon is well known in the art and no further discussion is deemed necessary. The photocell of the detector 330 senses arcing and relays a signal along the cable 305. Microprocessor 193 relays signals along cable 308 to close the convolute duct to prevent injury to personnel around furnace 78 and damage to the convolute duct apparatus.

Examples of the invention are discussed to shape two glass sheets. As can now be appreciated, the invention is not so limited and can be practiced with one sheet or more than two sheets (e.g., without limitation, three, four, or more sheets).

The invention may be further characterized by the following numbered clauses.

Clause 1: a method of shaping a glass sheet comprising:

a. preheating glass sheets on a bending iron (70) to a preheating temperature in a range from 600 ° f to 1000 ° f;

b. increasing the temperature of the sheet to a temperature ranging from greater than the pre-heating temperature to less than the temperature of the glass sag;

c. bending the glass sheet by:

i. selectively heating a portion of the glass sheet to a temperature at which at least a portion of the glass sheet sags with a device (177) that generates ultra-high frequency, high power electromagnetic waves controlled by a computer implemented protocol;

scanning at least a portion of the glass sheet with one or more thermal sensors (324) at one or more points in time during or after the selective heating step, and obtaining a temperature profile in at least two dimensions for the at least a portion of the glass sheet from data obtained from the one or more thermal sensors (324);

comparing the obtained temperature distribution to a reference temperature distribution of the computer implemented protocol using a computer implemented process; and

selectively heating the glass sheet with a beam (225) of an ultra-high frequency, high power device (177) controlled by a computer-implemented process to match the obtained temperature profile to a reference temperature profile of the computer-implemented protocol.

Clause 2: the method of clause 1, wherein the device (177) that generates the ultra-high frequency, high power electromagnetic wave is a gyrotron.

Clause 3: the method of clause 1 or 2, further comprising repeating steps ii. to iv. of the bending step until the obtained temperature distribution matches the reference temperature distribution of the computer implemented protocol.

Clause 4: the method of any of clauses 1-3, wherein the bending step c.

v. obtaining position data of at least a portion of the glass sheet from one or more position sensors (320 and 321) at one or more points in time during the selective heating step and generating a shape curve for the glass sheet using computer-implemented processing at the one or more points in time;

comparing the generated shape curve to a reference shape curve of the computer-implemented protocol using a computer-implemented process; and

selectively heating the glass sheet with a beam (225) of a ultrahigh frequency, high power device (177) controlled by a computer implemented process to match the shape curve of the glass sheet to the reference shape curve.

Clause 5: the method of clause 4, further comprising repeating steps v.through vii of the bending step until the obtained shape curve matches the reference shape curve of the computer implemented protocol.

Clause 6: the method of clauses 4 or 5, wherein the comparing steps iii.

Clause 7: the method of any of clauses 4-6, wherein one or more of the position sensors (320 and 321) is a camera or a charge-coupled device (CCD).

Clause 8: the method of clause 7, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from a plurality of CCDs.

Clause 9: the method of clause 7, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from a plurality of laser sensors.

Clause 10: the method of any of clauses 4-9, wherein one or more of the one or more position sensors (320 and 321) are laser sensors.

Clause 11: the method of any of clauses 1-10, wherein the glass sheet is cut to a desired size prior to heating and shaping.

Clause 12: the method of any of clauses 1-11, wherein the thermal sensor (324) is an IR scanner or/and IR imaging sensor, optionally a laser sensor.

Clause 13: a system, comprising:

a first oven (76) including an infrared heater (172) and a temperature sensor (191); and

a second oven (78) comprising an infrared heater (172); a device (177) generating ultra-high frequency, high power electromagnetic waves; and an optical system for controlling the shape, position and movement of the device's beam onto the glass sheet on the bending iron in the second furnace (78); and one or more Infrared (IR) imaging sensors;

a conveyor system for carrying glass sheets on a bending iron (70) through the first and second furnaces (76 and 78);

a computer system connected to the one or more IR imaging sensors and the ultra-high frequency, high power device (177), comprising a processor and instructions for controlling bending of the glass sheet in the second furnace (78) by selective heating by the ultra-high frequency, high power device (177), the instructions comprising a computer-implemented protocol for heating and bending the glass sheet in the second furnace (78), wherein the computer system obtains a temperature profile of the glass sheet from the one or more IR imaging sensors (324) at one or more points in time during bending of the glass, compares the obtained temperature profile to a reference temperature profile of the computer-implemented protocol, and controls the ultra-high frequency, high power device (177) to selectively heat the glass sheet to match the reference temperature profile; and

a third furnace (260) for controllably cooling the glass sheet includes an IR heater, a forced air convection system, and a fan.

Clause 14: the system of clause 13, wherein the device that generates the ultra-high frequency, high power electromagnetic waves (177) is a gyrotron.

Clause 15: the system of clause 13 or 14, further comprising one or more position sensors (230 and 231) in the second furnace (78) configured to obtain position data for one or more portions of the glass sheet during bending, wherein the position sensors (230 and 231) are connected to the computer system, and the computer system:

a. obtaining data from the one or more position sensors (230 and 231) at one or more points in time during bending of the glass sheet;

b. generating a shape curve for the glass sheet from the obtained data from the one or more position sensors at the one or more time points;

c. comparing the obtained shape curve to a reference shape curve of the computer-implemented protocol; and

d. the UHF, high power device (177) is controlled to selectively heat the glass sheet to match the shape curve of the glass sheet to the reference shape curve.

Clause 16: the system of clause 15, wherein one or more of the one or more position sensors (230 and 231) is a charge-coupled device (CCD).

Clause 17: the system of clause 16, which includes a plurality of CCDs, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from the plurality of CCDs.

Clause 18: the system of any of clauses 15-17, wherein one or more of the one or more position sensors (230 and 231) is a laser sensor.

Clause 19: the system of clause 18, which includes a plurality of the laser sensors, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from the plurality of CCDs.

Clause 20: the system of any of clauses 13-19, wherein one or more of the one or more IR imaging sensors (324) is a laser sensor or a CCD.

Clause 21: the system of any of clauses 13-20, further comprising a third furnace (260) having an IR heater, and wherein the conveyor system further carries the glass sheet through the third furnace.

Clause 22: the system of clause 21, wherein the first furnace, the second furnace, and the third furnace (76, 78, and 260) form a single tunnel.

Clause 23: the system of clause 22, including doors between the first and second ovens (76 and 78) and between the second and third ovens (78 and 260).

Clause 24: the system of any of clauses 13-23, wherein the computer system obtains the temperature of the first furnace and adjusts the temperature of the first furnace (76) using the IR heater to match the preheat temperature according to the computer implemented protocol.

Clause 25: the system of any of clauses 13-24, wherein the computer system obtains an ambient temperature of the second furnace (78), and adjusts the temperature of the second furnace (78) using the IR heater to match a temperature ranging from greater than the pre-heat temperature to less than the temperature of the glass sag.

It will be readily appreciated by those skilled in the art that modifications may be made to the non-limiting embodiments of the invention disclosed herein without departing from the concepts disclosed in the foregoing description. Accordingly, the particular non-limiting embodiments of the present invention described in detail herein are illustrative only and are not limiting to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.

Claims (22)

1. A method of shaping a glass sheet comprising:

a. preheating glass sheets on a bending iron to a preheating temperature ranging from 600 ° f to 1000 ° f;

b. increasing the temperature of the sheet to a temperature ranging from greater than the pre-heating temperature to less than the temperature of the glass sag;

c. bending the glass sheet by:

i. selectively heating a portion of the glass sheet to a temperature at which at least a portion of the glass sheet sags with a device that generates ultra-high frequency, high power electromagnetic waves controlled by a computer implemented protocol;

scanning at least a portion of the glass sheet with one or more thermal sensors at one or more points in time during or after the selective heating step and obtaining a temperature profile in at least two dimensions for the at least a portion of the glass sheet from data obtained from the one or more thermal sensors;

comparing the obtained temperature distribution to a reference temperature distribution of the computer implemented protocol using a computer implemented process;

selectively heating the glass sheet with a beam of an ultra-high frequency, high power device controlled by a computer-implemented process to match the obtained temperature profile to a reference temperature profile of the computer-implemented protocol;

v. obtaining position data of at least a portion of the glass sheet from one or more position sensors at one or more points in time during the selective heating step and generating a shape curve for the glass sheet using computer-implemented processing at the one or more points in time;

comparing the generated shape curve to a reference shape curve of the computer-implemented protocol using a computer-implemented process;

selectively heating the glass sheet with a beam of a computer-implemented process-controlled UHF, high-power device to match the shape curve of the glass sheet to the reference shape curve,

wherein the comparison steps iii.

2. The method of claim 1 wherein the device that generates the ultra-high frequency, high power electromagnetic waves is a gyrotron.

3. The method of claim 1, further comprising repeating steps ii. to iv. of the bending step until the obtained temperature distribution matches a reference temperature distribution of the computer implemented protocol.

4. The method of claim 1, further comprising repeating steps v.through vii of the bending step until the obtained shape curve matches a reference shape curve of the computer implemented protocol.

5. The method of claim 1, wherein one or more of the position sensors are cameras, charge-coupled devices (CCDs), or laser sensors.

6. The method of claim 5, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from a plurality of CCDs.

7. The method of claim 5, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from a plurality of laser sensors.

8. The method of claim 1, wherein one or more of the one or more position sensors are laser sensors.

9. The method of claim 1, wherein the glass sheet is cut to a desired size prior to heating and shaping.

10. The method of claim 1, wherein the thermal sensor is an IR scanner or an IR imaging sensor.

11. A system for shaping a glass sheet comprising:

a first oven including an infrared heater and a temperature sensor;

a second furnace comprising an infrared heater, a device for generating ultra-high frequency, high power electromagnetic waves, and an optical system for controlling the shape, position and movement of the device's beam onto the glass sheet on the bending iron within the second furnace, and one or more Infrared (IR) imaging sensors;

a conveyor system for carrying glass sheets on a bending iron through the first furnace and the second furnace;

a computer system connected to the one or more IR imaging sensors and the ultra-high frequency, high power device, comprising a processor and instructions for controlling bending of the glass sheet in the second furnace by selective heating by the ultra-high frequency, high power device, the instructions comprising a computer-implemented protocol for heating and bending the glass sheet in the second furnace, wherein the computer system obtains a temperature profile of the glass sheet from the one or more IR imaging sensors at one or more points in time during bending of the glass, compares the obtained temperature profile to a reference temperature profile of the computer-implemented protocol, and controls the ultra-high frequency, high power device to selectively heat the glass sheet to match the reference temperature profile;

a third furnace for controllably cooling the glass sheet, the third furnace comprising an IR heater, a forced cooling air convection system, and a fan;

one or more position sensors in the second furnace, the one or more position sensors configured to obtain position data for one or more portions of the glass sheet during bending, wherein the position sensors are connected to the computer system, and the computer system:

a. obtaining data from the one or more position sensors at one or more points in time during bending of the glass sheet;

b. generating a shape curve for the glass sheet from the obtained data from the one or more position sensors at the one or more time points;

c. comparing the obtained shape curve to a reference shape curve of the computer implemented protocol while comparing the obtained temperature curve to a reference temperature profile of the computer implemented protocol; and

d. controlling the UHF, high power device to selectively heat the glass sheet to match the shape curve of the glass sheet to the reference shape curve.

12. The system of claim 11, wherein the device that generates the ultra-high frequency, high power electromagnetic waves is a gyrotron.

13. The system of claim 11, wherein one or more of the one or more position sensors is a Charge Coupled Device (CCD).

14. The system of claim 13, comprising a plurality of CCDs, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from the plurality of CCDs.

15. The system of claim 11, wherein one or more of the one or more position sensors are laser sensors.

16. The system of claim 15, comprising a plurality of the laser sensors, wherein the shape curve is a three-dimensional shape curve compiled from data obtained from the plurality of laser sensors.

17. The system of claim 11, wherein one or more of the one or more IR imaging sensors is a laser sensor or a CCD.

18. The system of claim 11, further comprising a third furnace having an IR heater, and wherein the conveyor system further carries the glass sheet through the third furnace.

19. The system of claim 18, wherein the first furnace, the second furnace, and the third furnace form a single tunnel.

20. The system of claim 19, comprising doors between the first furnace and the second furnace and between the second furnace and the third furnace.

21. The system of claim 11, wherein the computer system obtains the temperature of the first furnace and adjusts the temperature of the first furnace using the infrared heater to match a preheat temperature according to the computer-implemented protocol.

22. The system of claim 11, wherein the computer system obtains an ambient temperature within the second furnace and adjusts the temperature within the second furnace using the infrared heater to match a temperature ranging from greater than a preheat temperature according to a computer implemented protocol to less than a temperature of the glass sag.

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