JPH06100325A - Plate glass form and its production - Google Patents

Abstract

PURPOSE:To provide a plate glass form having bent portion(s), extremely small in the radius of curvature of the outer periphery of the curved surface rectangular to the bent portion, also extremely low in both the optically transmissive and reflective strains for planar portions. CONSTITUTION:The objective plate glass form having at least one straight-line bent portion and made up of plural planar portions. In producing such a plate glass form, a bending line is drawn, using an electrically conductive material, at each site where the plate glass is to be bent, and the glass at the site is electrically heated to a temperature higher than the softening point of this plate glass followed by bending the plate glass along the line. The present plate glass has the following additional characteristics: (1) the radius of curvature of the outer periphery of the curved surface rectangular to the above bent portion(s) is 1 to 4 times the thickness of the plate glass at the planar portions and (B) the surface of the plate glass at the planar portions is virtually flat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet glass molded product for construction and general industry, and a method for producing the same, and more specifically, a single sheet glass molded product composed of a plurality of flat surfaces which are seamless in bent portions. And its manufacturing method.

[0002]

2. Description of the Related Art In recent years, sheet glass has been widely used for various purposes such as building exteriors and interiors or for general industry, for example, windows, show windows, wall materials, doors, partitions, display cases, aquariums, furniture and the like. ing. Conventionally, at the corners of windows, show windows, display cases, etc., two plate glasses are joined at a predetermined angle using a frame made of metal, wood, plastic, etc., and the joint between each plate glass and frame is made of silicone rubber, etc. Was adhered by a caulking material and a sealing material. However, this method has a drawback in that the appearance and transparency of the corner portion are poor due to the presence of the frame, and when a stainless steel frame or the like is used in the corner portion, the cost increases and it is not economically preferable. . On the other hand, there is a method of abutting two sheet glasses together without using the frame and joining the abutting portions with a caulking material and a sealing material such as silicone rubber. However, this method does not improve the appearance and the transparency of the corner portion, and the joined butted portion is weak in strength. In addition, since the caulking material and the sealing material have a limited weather resistance, the life of the joint is generally relatively short. As a method for eliminating the above-mentioned defects, it is known to heat a sheet of glass plate to form a bent portion having a predetermined angle. For example, a normal float plate glass is placed horizontally on the upper part of a mold having a bent portion having a predetermined angle, the whole plate glass is heated to about 500 to 580 ° C., and the bent portion is locally 700 to 750 ° C.
It is performed by heating to a certain degree and molding on a mold by gravity or other external force to make a predetermined bent portion. However, in this method, the bent portion has a relatively large radius of curvature (for example, when the plate glass has a thickness of 4 mm, the minimum radius of curvature is about 35 to 40 mm), a window, a water tank,
When it is used for a show window, a display case, etc., the object looks distorted, which is not preferable. In addition, since the vicinity of the bent portion of the plate glass is exposed to a high temperature equal to or higher than the annealing temperature over a considerable range, distortion occurs in the vicinity of the bent portion of the sheet glass after molding over a considerable range, and there is a drawback that the distortion of the flat portion is large. Was there. FIG. 5 shows an example of a cross section in the bending direction of a sheet glass having a bent portion formed by the above method. The radius of curvature at the bent portion B ₁ is about 10 times the thickness of the sheet glass, and the AB ₁ and AB ₂ portions are several times the thickness d as an intermediate portion between the flat portions A ₁ , A ₂ and the bent portion B _1. Of the optical characteristics, which are distorted over the length of, and the flat surfaces A ₁ and A ₂ are also exposed to high temperature, and as a result, the flatness before heat processing cannot be maintained, and There is a perspective distortion and a reflection distortion.

[0003]

DISCLOSURE OF THE INVENTION According to the present invention, in a single sheet glass molded body composed of a plurality of flat surfaces which are seamless in the bent portion, the radius of curvature of the outer circumference of the curved surface in the direction perpendicular to the bent portion is extremely small. The present invention also provides a plate glass molded body having an extremely small optical perspective distortion on each glass plane and a method for producing the plate glass molded body.

[0004]

In order to eliminate the above-mentioned drawbacks caused by the conventional bending method for sheet glass, the present inventor has
As a result of earnest studies, a manufacturing method of a sheet glass molded body was completed in which only the bending line portion drawn on the sheet glass was heated to a high temperature, and the other portions were kept at an appropriate temperature to perform bending. In addition, a plate glass molded body was completed in which the bent portion of the plate glass was extremely sharp and there was no distortion in the flat portion.

That is, the present invention provides a method for producing a single sheet glass molded body having a plurality of flat portions having at least one linearly bent portion, wherein a conductive material is used at a portion to be bent on the sheet glass. Drawing a bending line, electrically heating the glass of the bending line portion to a temperature equal to or higher than the softening point of the plate glass, and then bending the plate glass along the bending line. Is. Further, the present invention is a plate glass molded body having a plurality of flat portions having at least one linear bending portion, wherein the radius of curvature of the outer periphery of the curved surface in the direction perpendicular to the bending portions is in the flat portion. It is a plate glass molded body characterized by being 1 to 4 times the thickness of the plate glass and having a flat plate glass surface which is substantially flat.

According to the method of the present invention, since the method of electrically heating the glass of the bent line portion drawn on the plate glass is adopted, the plate glass can be extremely locally heated to a predetermined temperature. . Therefore, the flat portion other than the heated portion is not subjected to unnecessary high temperature heating, thermal deformation is completely prevented, and the flatness is maintained even after bending. Preferably by heating to a predetermined temperature below the glass softening point by radiant heating and / or heat transfer heating other than the above-mentioned bending line portion, the two-dimensional internal stress in the plate glass generated during heating is reduced, and during bending. It is possible to prevent breakage of the plate glass. Moreover, since the width of the region heated near the softening point along the bending line is narrow, the bent portion can be made extremely sharp.

That is, the flat glass molded body produced by the method of the present invention has a very sharp bent portion,
Moreover, the planarity of the two adjacent planes is extremely good up to the vicinity of the bent portion. This is a surprisingly superior quality that cannot be imagined from conventional products.

First, in the method for producing a sheet glass molded body of the present invention, any known conductive material can be used as the conductive material used to draw the bending line. The conductive material is preferably a conductive paint or metal or alloy such as carbon-based or metal-based such as silver, palladium, platinum or oxide-based such as tin oxide, for example, iron-nickel-chromium alloy, copper-tin. An alloy, an aluminum alloy, etc. are mentioned. Carbon graphite conductive paint such as Bunny Height (F-525W-1) manufactured by Nippon Graphite Trading Co., Ltd., and silver conductive paint Hokuriku Paint Co., Ltd.
9100 or Fujikura Kasei Co., Ltd. D-1230 (modification) etc. are mentioned. It can be appropriately selected from these, depending on the size, thickness, bending angle, bending speed, operating voltage, etc. of the plate glass.

The paste-like conductive paint is drawn linearly on the surface of the plate glass by screen printing, letterpress printing, spraying or transfer. The metal or alloy can be applied by metal spraying, CVD, or pyrolytic methods. In the metal spraying method, a mask having slits corresponding to bending lines is placed on a glass plate, the above metal is used as a conductive material, the metal is melted by an electric arc or flame, and blown from a nozzle with compressed air. Then, spray the plate glass surface and draw a bending line. In any of the above-mentioned methods, the drawn fold line is in close contact with the surface of the plate glass and can be printed accurately at a predetermined location. Screen printing and metal spraying are preferred because of their accuracy and simplicity. The number of the folding lines is the same as the number of bent portions of the flat glass molded body required as a product, and at least one is drawn on one flat glass. When a plurality of folding lines are drawn, they may be drawn in parallel or non-parallel to each other depending on the desired product shape. An example of the shape of the product is shown in FIG.

The width of the fold line varies depending on the above-mentioned factors (that is, the size, thickness, bending angle, bending speed, working voltage, etc. of the glass sheet), but it is preferably 0. It is 3 to 3 times, and particularly preferably 0.5 to 1.5 times. When the width of the bending line exceeds three times the thickness of the plate glass in the flat portion, the range of the plate glass heated near the softening point is too wide and the bent portion is not sharp. If the width is less than 0.3 times, sufficient heating cannot be performed and the wall thickness of the bent portion decreases, which is not preferable. The thickness of the fold line varies depending on the type of conductive material and the method used to draw the fold line, but it suffices that the glass can be stably heated to a predetermined temperature for a predetermined time, and preferably 0.1 to several. It is preferably 100 μm, for example, 10 to 100 μm in the screen printing method and 30 to 300 μm in the thermal spraying method.

The bending line may be drawn on one surface, both surfaces, one surface and both end surfaces of the plate glass, or a loop connecting the both surfaces and both end surfaces. In general, when the plate glass is thin, a fold line is drawn only on the surface which is an outer side when the plate glass is bent. When the plate glass is thick, it is preferable to draw folding lines on both sides. When performing the dielectric heating described later, it is necessary to draw a fold line continuously in a loop shape.

The plate glass used in the present invention may be any one as long as it can be used for construction or general industry. The plate glass may be produced by any known method, but it is necessary that the flat portion of the plate glass molded body produced by the method of the present invention has no distortion,
It is preferred to use a float glass sheet formed on molten tin metal. The plate thickness, shape and size of the plate glass used are determined according to the purpose and are not particularly limited. The composition is not particularly limited, and plate glass having various softening points such as commonly used soda-lime glass, borosilicate glass, and high-strength crystallized glass can be used. The type of the plate glass is not particularly limited, and ordinary plate glass, netted plate glass, polished plate glass, shaped plate glass and the like are used. Further, the above plate glass may be subjected to various surface treatments such as heat ray reflective coating, non-reflective coating, specific pattern printing and surface etching.

As a method of electrically heating the glass of the bent line portion drawn on the plate glass, the method described below is preferably used. That is, a method in which a solid electrode having an appropriate shape is brought into contact with the bending line at the edge of the plate glass to supply power and heat, and a conductive high temperature gas frame that generates lithium ions etc. is brought into contact with the bending line at the edge of the plate glass. It is a method of heating by feeding power through, or a method of drawing a bent line in a loop shape and performing dielectric heating using a high frequency current. The current used in the above method is an alternating current of 50 or 60 Hz, which is generally used for commercial purposes, and 10
A high frequency current or a direct current of 0 KHz to 50 MHz is used. While any of the above types of current can be used in the method using the solid electrode, a high frequency current is preferable in the method using a conductive high temperature gas flame, and only a high frequency current can be used in the dielectric heating. The selection of the type of current to be used is determined in consideration of the type of method for heating the bent line portion, the size of the plate glass, and the like. In addition, the control of the electric heating, the thickness of the plate glass used,
Considering the dimensions, the width of the bending line, the temperature distribution over the entire surface of the glass sheet, the bending speed of the glass sheet during forming, the final bending angle, etc., it is preferable to control the energization time. The control factors include a number of parameters such as
In addition, since the temperature distribution on the entire surface of the plate glass changes with time, the temperature control is preferably performed by computer control. Usually, for several seconds to five minutes, especially for one to three minutes, the bending line length of 10 cm to several tens to several 1
A heating of 00 W is possible, which is sufficient (in the conventional bent glass manufacturing method, heating took 20 minutes).

By the above heating method, the bent line portion drawn on the plate glass is heated to a predetermined temperature. The temperature is
The temperature of the plate glass of the bent line portion is equal to or higher than the softening point of the used plate glass, and particularly preferably in the range of the softening point to the softening point plus 140 ° C. When the temperature exceeds the above range, the flat portion near the bending line after bending is distorted, and it is not preferable from the economical viewpoint. Here, the softening point of the glass sheet corresponds to a temperature at which the glass has a viscosity of about 10 ⁸ poise and is deformed by its own weight (normal float glass has a temperature of about 740 ° C.).

In order to achieve the method of the present invention more preferably, damage to the glass sheet due to two-dimensional internal stress temporarily generated in the glass sheet due to the non-uniform temperature distribution generated by heating the bent line portion. Must be prevented. In the method of the present invention, it is preferable to use the heating method described below in combination in order to control the edge tension to be equal to or lower than the breaking strength.

That is, it is preferable to radiatively heat the plate glass near the bending line. The radiant heating is preferably performed using a sheath heater or a halogen lamp.
For example, a rod-shaped sheathed heater having a diameter of 15 mm is installed in parallel with the bending line at a position about 40 mm away from the bending line in a direction perpendicular to the plate glass surface. Further, it is preferable to radiantly heat and / or heat transfer heat the entire plate glass. The heat transfer heating is preferably performed by sandwiching a portion other than the vicinity of the bending line of the plate glass with a heating plate. For example, heating is performed by bringing a flexible heater for heat transfer into contact with both surfaces of the glass, and sandwiching the flexible heater on the glass surface with a heat insulating material placed thereon.

By the heating as described above, preferably, the temperature of the plate glass portion within the range of 3 cm or more in the right and left directions from the above-mentioned bending line is set to a temperature lower than the softening point of the used plate glass by 200 to 500 ° C. From the right-hand side to the glass plate portion in the range of less than 3 cm (for example, 2 cm may be left and right) at a temperature higher than that of the glass plate portion in the range of 3 cm or more, and the plate glass of the bending line portion is at a softening point of the glass plate or more. The temperature.
More preferably, a temperature gradient is provided between the fold line and the peripheral edge facing it. For example, a plate glass portion within 5 cm from the peripheral portion in the direction of the bending line is set to a temperature 400 to 500 ° C. lower than the softening point of the plate glass, and a peripheral portion facing the bending line at 3 cm or more in each of the right and left in the direction perpendicular to the bending line. Therefore, the temperature of the plate glass portion in the range exceeding 5 cm in the folding line direction is set to the temperature of the peripheral portion or more.

An example of the temperature distribution on the glass sheet achieved by the method of the present invention is shown in FIG. In the figure, the plate glass G has a length of 400 mm, a width of 800 mm, and a thickness of 4 mm,
The softening point is 740 ° C. A folding line L is drawn in the center of the plate glass in the horizontal direction. When this is heated according to the method of the invention, the temperature distribution of the glass along the line XX 'is shown in the figure. The position p on the plate glass G is also indicated by p on the temperature distribution. In the temperature distribution along the line XX ′, the range of about 6 mm on each of the left and right sides of the bending line L is 8
It is close to 00 ° C. At the radiantly heated portion on the outer side, the temperature sharply drops between the bending line L and 2.5 cm. It is about 450 ° C. at a point p located about 10 cm from the bending line L, and the temperature is almost constant up to the peripheral portion. That is, in the present invention, in order to maintain the flatness of the glass near the folding line, the temperature distribution in the vicinity of the folding line L is made extremely sharp, but by appropriately controlling the temperature distribution of the entire glass plate, It can prevent the glass from breaking.

In addition to the above temperature distribution in the direction perpendicular to the bending line, also in the direction parallel to the bending line,
It is preferable (but not essential) to provide a given temperature distribution. That is, in the temperature distribution of the plate glass in a direction parallel to the bending line at each of 10 cm on the right and left sides in the direction perpendicular to the bending line, the temperature of the peripheral portion of the plate glass is 30 to 150 ° C. higher than the temperature of the central plate glass, preferably 50. It is preferable to set the temperature higher by -100 ° C. By achieving the temperature distribution, it is possible to more preferably prevent breakage of the plate glass due to the two-dimensional internal stress. The predetermined temperature distribution parallel to such a bending line is
This can be achieved by radiant heating and / or heat transfer heating for heating the peripheral portion.

FIG. 3 shows an example of the temperature distribution in which the temperature distribution in the direction parallel to the bending line is given. In the figure, the plate glass G ₁ is the same as the plate glass of FIG. When this is heated according to the method of the invention, the temperature distribution of the glass along the line X ₁ X ₁ ′ and the temperature distribution of the glass along the line Y ₁ Y ₁ ′ are shown in the figure. Position p ₁ on the glass sheet G ₁ is
It is also indicated by p ₁ on the two temperature distributions. Line X ₁
In the temperature distribution along X ₁ ′, the range of about 6 mm on each of the left and right sides of the bending line L ₁ is near 800 ° C.,
When the temperature further advances in the peripheral direction, the temperature slightly decreases. The temperature is about 350 ° C. at a point p ₁ located about 10 cm from the bending line L ₁ . From there, the temperature drops more slowly, around 250 ° C at the periphery. On the other hand, line Y
_{In the} temperature distribution along ₁ Y ₁ ′, the peripheral portion has a higher temperature than the center, which is important for preventing the glass from cracking due to two-dimensional stress. That is, in the invention, in order to maintain the flatness of the glass near the bending line, the bending line L ₁
In spite of making the temperature distribution extremely sharp in,
By appropriately controlling the temperature distribution of the entire glass plate, it is possible to prevent the glass from cracking, which is preferable. Figure 3
In the embodiment, the total amount of heat for heating the glass plate is smaller than that in FIG.

The above-mentioned heating in the method of the present invention is usually performed in air, but is not limited to this.

In the method of the present invention, preferably,
After performing radiant heating and / or heat transfer heating on the entire plate glass, the plate glass portion near the bending line is radiantly heated,
Then, it is preferable to electrically heat the glass of the bent line portion. By heating in this order, it is possible to easily achieve a temperature distribution having an appropriate peak in the bent line portion.

In the method of the present invention, the method of bending the flat glass sheet at a predetermined angle along the bending line is usually carried out by a suitably designed glass sheet holding mechanism. At that time, the bending speed, the bending external force and the final bending angle are precisely controlled through the holding mechanism. This prevents the occurrence of cracks in the bent portion, and makes it possible to obtain a predetermined cross-sectional shape and wall thickness of the bent portion. When radiant heating and / or heat transfer heating is used for the flat portion, it is preferable to provide a plate glass holding mechanism in the apparatus used for the heating and bend the plate glass at a predetermined angle by the glass holding mechanism.
As the plate glass holding mechanism, for example, a flexible heater for heat transfer is brought into contact with both sides of the glass, a heat insulating material is placed thereon, and further, a plate attached to the arm is sandwiched and sandwiched between the plates, An example is a device that bends a plate glass at a predetermined angle by moving an arm by power. Thereby, the internal angle between two adjacent planes is preferably set to 60 to 160 degrees. The bending operation can be completed in a very short time, usually 1 to
5 minutes is preferred.

The conductive material having the above-mentioned folding line is
Usually, it is removed after the above thermoforming. Many of the components of the conductive material gradually burn or scatter during heating, and may remain little after the completion of molding. From this point, a carbon-based conductive paint is preferable. Depending on the type of conductive material or the thickness thereof, it may remain completely on the glass surface due to complete burning. In such a case, oxygen can be blown and completely burned to be removed after the heat molding, or the glass can be removed by an appropriate mechanical method or chemical method such as polishing after cooling. Further, from a design point of view, when it is desired to leave a line made of a conductive material in a completed sheet glass molded body, a conductive material having a predetermined composition that gives a desired color tone is used in advance. You can draw folding lines.

The glass after the heat-molding is post-treated in the same manner as in the conventional case, and can be subjected to, for example, slow cooling or rapid cooling to obtain a slowly cooled product, a strengthened product or a double strengthened product. Also a heat ray reflective coat,
Various surface treatments such as anti-reflection coating, printing of a specific pattern, and etching of the surface can also be performed.

In one sheet glass molded body having a plurality of flat portions having at least one linear bending portion manufactured by the method of the present invention, the curvature of the outer circumference of the curved surface in the direction perpendicular to the bending portion. The radius is 1 to 4 times the thickness of the flat glass in the flat portion, preferably 1
~ 3 times. If the radius of curvature exceeds four times the thickness of the glass sheet, the distortion of the see-through object becomes large at the bent portion, which is not preferable, and if it is significant, the see-through object looks enlarged. On the other hand, if the radius of curvature is less than 1 time,
It is not preferable in terms of safety for humans because the strength of the corner portion is small. Further, a transition region which is slightly deformed and loses flatness may be present between the bent portion and the plane portion, and the width of the transition region is preferably twice the thickness of the glass sheet or less, and particularly, It is preferably 1 time or less. If the width exceeds twice, the object seen through in the plane portion near the bent portion is distorted, which is not preferable. The flat glass surface of the flat portion of the flat glass molded body is substantially flat. For example, in the case of a plate glass molded body using a float plate glass, the flatness of the float plate glass before bending is maintained as it is.

FIG. 1 shows an example of a cross section in the bending direction of the bent portion of the sheet glass molded product according to the present invention. R in the figure is the radius of curvature according to the present invention. Points P and Q are the points where the curved surface begins. Outside the bending points P and Q of the molded sheet glass of the present invention, a portion having a relatively poor optical property, which is apparently flat but is slightly deformed to impair the flatness, that is, a transition region S.
May exist. In the conventional flat glass having a bent portion, the radius of curvature is extremely large as shown in FIG. 5, the boundary between the flat portion and the bent portion is not clear, and the glass is slightly deformed in the middle from the flat portion to the bent portion. Then, there is a transition region over a considerable length which impairs the planarity.
On the other hand, the flat glass molding of the present invention is remarkably different.

The above-mentioned sheet glass molded article refers to one having at least one corner portion, and examples thereof include various molded articles as shown in FIG.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0030]

Example 1 400 mm long, 800 mm wide, 4 mm thick
Of a rectangular float glass plate (soda lime glass, softening point 740 ° C.) in the horizontal center and in the vertical direction using a silver-based conductive material (trademark D-1230 (modified), Fujikura Kasei Co., Ltd.) A folding line having a width of 2 mm and a thickness of 20 μm was drawn on one surface and both end surfaces of the plate glass by using a screen printing method. A solid electrode was placed at the end of the fold line. Then, a rod-shaped sheathed heater having a diameter of 15 mm was placed parallel to the bending line at a position 40 mm away from the bending line in the direction perpendicular to the plate glass surface. In addition, the heat transfer heating device consisting of a flexible heater is placed on the left and right 5
The plate was placed over the entire surface of the plate glass, leaving the cm. The heat transfer heating device is installed so as to sandwich the plate glass from both sides, and functions as a plate glass holding mechanism. Next, first, heat transfer heating is started to heat the whole plate glass to 450 ° C.,
Radiant heating near the fold line, then 50
A current of Hz and AC38V was applied for 2 minutes to heat the plate glass of the bent line portion to 800 ° C. The plate glass surface had the predetermined temperature distribution shown in FIG. Then, the plate glass was bent by the plate glass holding mechanism in such a manner that the two flat surfaces were perpendicular to each other in about 1 minute. After molding in this way, it was gradually cooled to produce a plate glass molded body.

The radius of curvature of the outer periphery of the curved surface in the direction perpendicular to the bent portion of the manufactured sheet glass molded body is 5 mm, which is 1.2 times the thickness of the sheet glass in the flat portion, and is slightly deformed to provide flatness. Almost no missing transition region was seen. Further, the flat surface portion of the flat glass molded body maintained the original flatness of the float flat glass used in the method of the present invention, and no increase in optical perspective distortion and reflection distortion was observed.

As described above, the bent portion of the sheet glass molded body produced according to the present invention was very sharp, and the flat portion thereof had no distortion and had excellent transparency.

[0033]

According to the present invention, a flat glass molded product having a bent portion, in which the radius of curvature of the outer circumference of the curved surface in the direction perpendicular to the bent portion is extremely small, and the optical perspective distortion and the reflection distortion of the flat surface portion are extremely small. Is obtained.

[Brief description of drawings]

FIG. 1 is an example of a cross-sectional view in a bending direction of a bent portion of a sheet glass molded product of the present invention.

FIG. 2 is an example of the temperature distribution on the glass sheet achieved by the method of the present invention.

FIG. 3 is an example of the temperature distribution on the glass sheet achieved by the method of the present invention.

FIG. 4 is an example of a sheet glass molded product of the present invention.

FIG. 5 is an example of a sectional view in the bending direction of a bent sheet glass manufactured by a conventional method.

[Explanation of symbols]

R: radius of curvature of the outer periphery of the curved surface in a direction perpendicular to the bent portion S: transition region P, Q: starting point of bent portion d: thickness of sheet glass G, G ₁ : sheet glass L, L ₁ : bending line A ₁ , a _2: planar portion AB _1, AB _2: planar portion a _1, a transition of a ₂ and the bending portion B ₁ region B _1: bent portion

Claims (13)

[Claims] 1. A method of producing a single sheet glass molded body having a plurality of flat portions having at least one linearly bent portion, wherein a bending line is formed at a place to be bent on the sheet glass by using a conductive material. A method for producing a sheet glass molded body, which comprises drawing, electrically heating the glass of the bending line portion to a temperature equal to or higher than the softening point of the sheet glass, and then bending the sheet glass along the bending line. 2. The method of claim 1, further comprising radiatively heating a portion of the sheet glass near the fold line. 3. The method according to claim 1, further comprising radiant heating and / or heat transfer heating of the entire glass sheet. 4. A plate glass portion in a range of 3 cm or more in each of the right and left directions from the bending line is set to a temperature lower than the softening point of the plate glass by 200 to 500 ° C., and in a range of less than 3 cm in each of the right and left directions in the right direction from the bending line. The plate glass portion is set to a temperature higher than that of the plate glass portion in the range of 3 cm or more, and the plate glass of the bent line portion is set to a temperature equal to or higher than the softening point of the plate glass. The method described in. 5. A plate glass portion within 5 cm in the direction of the bending line from a peripheral portion facing the bending line is set to a temperature lower than the softening point of the plate glass by 400 to 500 ° C., and each of the left and right sides is 3 cm or more in the direction perpendicular to the bending line. The method according to claim 4, wherein the temperature of the plate glass portion in a range exceeding 5 cm in the direction of the bending line from the peripheral portion facing the bending line is set to be equal to or higher than the temperature of the peripheral portion. 6. The whole plate glass is radiantly and / or heat-transfer-heated, and then the plate glass portion near the fold line is radiantly heated, and then the glass of the fold line part is electrically heated. Item 6. The method according to any one of Items 4 and 5. 7. The apparatus for performing radiant heating and / or heat transfer heating according to claim 3 is provided with a plate glass holding mechanism, and the plate glass is bent by the holding mechanism. The method described in 1. 8. The width of the bending line drawn with a conductive material is 0.3 to 3 times the thickness of the plate glass in the flat portion, and the width of the bending line is 0.3 to 3 times. Method. 9. A single sheet glass molded body having a plurality of flat portions having at least one linearly bent portion, wherein the radius of curvature of the outer periphery of the curved surface in the direction perpendicular to the bent portions is flat glass in the flat portion. The thickness of 1
A glass sheet molded product which is four times larger and has a flat glass sheet surface which is substantially flat. 10. The flat glass molded product according to claim 9, wherein the radius of curvature is 1 to 3 times the thickness of the flat glass in the flat portion. 11. A transition region, which is slightly deformed and loses flatness, exists between the bent portion and the flat portion, and the width of the transition region is not more than twice the thickness of the glass sheet. The flat glass molded product according to claim 9, wherein 12. The sheet glass molded product according to claim 11, wherein the width of the transition region is not more than 1 time the thickness of the sheet glass. 13. The interior angle between two adjacent planes is 60 to 1.
It is 60 degrees, The flat glass molded body as described in any one of Claims 9-12 characterized by the above-mentioned.