TWI557082B - Plate glass forming method and forming mold - Google Patents

Description

Forming method of sheet glass and forming mold

The present invention relates to a method of forming a sheet glass of a curved plate glass having a curved shape, and a molding die for forming a curved plate glass.

In recent years, portable devices such as smart phones or tablet PCs have rapidly spread. In addition to the flat plate glass used in the past, for example, a curved plate glass having a curved surface having a constant radius of curvature is used.

Patent Document 1 discloses an example of a method for forming such a curved plate glass. In this document, it is described that the flat glass plate held by the heat-resistant sheet is heated and softened, and then the entire surface (one surface of the plate glass) of the plate glass is passed through the heat-resistant sheet and attached to the forming mold. The curved curved surface is formed by which the curved sheet glass is formed.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2012-116692

However, according to the method disclosed in Patent Document 1, in the case of forming a curved plate glass, there are the following problems to be solved. That is, in the molding method disclosed in this document, since the plate glass attached to the convex curved surface is softened by heating, the surface thereof is in a state of being extremely deformable.

Therefore, the fine unevenness and the like included on the convex curved surface may be transferred to the surface of the plate glass through the heat-resistant sheet, or the displacement may be caused by the movement at the time of attachment, thereby damaging the surface of the plate glass. . As a result, defects or damages, which are called pits and are convex or concave, remain on the surface of the curved plate glass after the forming, resulting in the curved plate glass. The situation in which the quality is greatly reduced.

In view of the above, in the case where the flat plate glass is formed into a curved plate glass, it is a technical problem of the present invention to prevent defects or flaws from remaining on the surface of the curved plate glass after molding as much as possible.

The method of the present invention to solve the above problems is a method for forming a flat plate glass into a curved plate glass having a curved shape, and the method includes a clamping step. The plate glass is clamped and supported in a plate thickness direction at two places spaced apart from one side of the square plate side of the plate glass, and at a position on the other side of the plate surface between the two places, thereby The sheet glass is elastically deformed to be in a bent state; and a heating step of forming the sheet glass into a curved sheet glass by heating the elastically deformed sheet glass.

According to such a method, the plate glass is sandwiched and supported at two places on one side of the one plate surface and the other on the other side of the plate surface, and the surface of the plate glass (one plate surface and the other plate surface) is sandwiched. The area of the contact portion with the foreign object is suppressed to an extremely small level, and the curved plate glass can be formed. Further, among the surfaces of the plate glass, it is possible to substantially avoid the occurrence of defects or scratches in the portion which is not in contact with the foreign object. As a result, it is possible to prevent the occurrence of defects or scratches on the surface of the curved plate glass after molding as much as possible.

In the above method, a forming mold having a concave curved surface and a convex curved surface facing the concave curved surface may be used, and a thickness is formed between the two curved surfaces relative to the sheet glass. The bending forming space having a large plate thickness; in the clamping process, it is preferable to sandwich and support the plate glass at two places of the concave curved surface and one of the convex curved surfaces.

In this manner, since the curved forming space having a large thickness is formed between the two curved faces with respect to the plate thickness of the plate glass, it is possible to prevent the forming die from exerting excessive pressure on the plate glass. Further, in this method, since the plate glass is sandwiched and supported at two places of the concave curved surface and the convex curved surface, the area of the portion where the two curved surfaces are in contact with the surface of the plate glass is suppressed. Very small. Therefore, it can be prevented as much as possible The surface of the plate glass was damaged.

In the above-described method, in the clamping step, it is preferable to maintain the sheet glass at a temperature which is not softened and deformed by heating, and the phrase "the temperature which is not softened by heating" is specifically referred to as a sheet glass. The viscosity is equivalent to a temperature of 10 ²⁰ dPa‧s. Further, it is preferable that the temperature of the sheet glass in the holding step is maintained at 300 ° C or lower, and it is more preferably maintained at 200 ° C or lower, and is maintained at a normal temperature (temperature range of 20 ± 15 ° C) as in the present embodiment. For the best.

In this way, in the nip process, since the sheet glass is at a temperature which is not softened and deformed by heating, the surface of the sheet glass can be kept in a state of being hard and not easily damaged. Thereby, it is possible to appropriately avoid the damage of the surface of the sheet glass due to the eccentricity or the like caused by the operation at the time of elastic deformation. Further, according to this method, in the case of forming a curved plate glass using a molding die, the sheet glass at a temperature which is not softened and deformed by heating may be placed on the molding die. Therefore, the sheet glass at a low temperature is placed on the forming mold as compared with the case where the softened sheet glass is placed. As a result, it is not easy to damage the equipment for placing the sheet glass, and the like, and it is possible to extend the life of such equipment. Further, in the case where the sheet glass is at a normal temperature, the sheet glass can also be placed on the forming mold by manual work by a person.

In the above method, it is also possible to make the concave curved surface and the convex curved surface curved in the same single direction.

By doing so, it is possible to form a curved sheet glass which is curved only in a single direction.

In the above method, the thickness of the curved molding space is preferably a thickness of 0.2 mm to 1.0 mm thick with respect to the sheet glass.

In this way, the curved surfaces of the concave curved surface and the convex curved surface can hold and support the plate glass in a stable state. Therefore, in the case where the curved plate glass is mass-produced, it is possible to suppress the occurrence of a jagged state in which the plurality of curved plate glasses are generated at the time of completion of the processing.

In the above method, in the heating step, it is preferable to form the sheet glass into a curved sheet glass in a temperature range in which the viscosity of the sheet glass is from 10 ⁸ dPa ‧ s to 10 ¹⁵ dPa ‧ s.

In this way, when the sheet glass is formed into a curved sheet glass, the effect of achieving good formability of the sheet glass and preventing the occurrence of defects or scratches on the surface of the curved sheet glass can be appropriately achieved.

In the above method, in the heating step, it is preferable to form the sheet glass into a curved sheet glass in a temperature range of ±50 ° C based on the cold spot of the sheet glass.

In this way, the forming of the curved sheet glass can be performed at the time of molding as long as necessary minimum heating, that is, the occurrence of the problem caused by the softening of the sheet glass can be suppressed as much as possible, and therefore, It is more appropriately prevented to leave defects or scratches on the surface of the curved plate glass after forming. Therefore, from the viewpoint of preventing damage to the surface of the sheet glass, it is difficult to receive the processing accuracy of the surfaces of the two curved surfaces of the forming mold, or the material selection of the forming mold. As a result, there is an advantage that the production of the molding die can be performed at low cost. Moreover, since it is only necessary to heat the sheet glass to the minimum temperature necessary at the time of molding, the electric power consumed by heating can be reduced. As a result, the manufacturing cost can be reduced.

In the above method, it is preferred to carry out a preheating step of preheating the forming mold before the holding step.

In this way, since the molding die for holding and supporting the sheet glass is heated in advance, it is also possible to shorten the time during which the sheet glass is heated to the molding temperature. Thereby, the production efficiency of the curved plate glass can be improved.

In the above method, the radius of curvature of the curved plate glass can be adjusted by adjusting at least one of the radius of curvature of the concave curved surface, the radius of curvature of the convex curved surface, and the distance between the two curved faces. Here, the "radius of curvature of the curved plate glass" includes not only the radius of curvature when the curved plate glass is bent with a constant curvature, but also the radius of curvature when the curvature is changed in a continuous state (for the concave curved surface) The radius of curvature and the radius of curvature of the convex curved surface are also the same).

By doing so, for example, it is possible to manufacture a curved plate glass having a substantially constant radius of curvature or a curved plate glass having a variable radius of curvature, and the like, and various curved plate glasses.

In the above method, the value of the coefficient of thermal expansion of the forming mold is preferably in the range of 0.1 to 10 times the value of the coefficient of thermal expansion of the sheet glass.

By doing so, it is possible to appropriately avoid the difference in the values of the thermal expansion coefficients of the forming mold and the sheet glass, both of which are heated When expanding, a situation such as a displacement deviation occurs between the two due to the difference in the degree of expansion thereof. As a result, it is possible to prevent the surface of the plate glass from being damaged due to the displacement deviation at the portion where the two are in contact with each other.

In the above method, in the sandwiching step, the sheet-like heat-resistant member is provided between the concave curved surface and one of the plate glass faces, and between the convex curved surface and the other plate surface of the plate glass. good.

By doing so, by providing the sheet-like heat-resistant member therebetween, the surface of the sheet glass can be prevented from coming into direct contact with the forming mold, and the surface of the sheet glass can be more safely protected from defects or damage. Thereby, it is possible to more appropriately prevent the surface from being depressed or scratched on the surface of the curved plate glass after the forming.

In the above method, in the heating step, the plate glass supported by the concave curved surface and the convex curved surface in the forming mold by the refrigerant flowing in the passage through the forming mold may be used. Each part is cooled.

In this way, since the respective portions of the sheet glass supported by the two curved surfaces are cooled by the refrigerant, it is possible to suppress the softening of these portions by heating, and it is possible to easily maintain a state in which it is hard and hard to be damaged. As a result, it is possible to more suitably prevent the occurrence of defects or damage on the surface of the curved plate glass after molding.

Moreover, the method of the present invention invented in order to solve the above-mentioned problems is a method of forming a flat plate glass into a curved plate glass having a curved shape, and as a feature thereof, a clamping process is included. The sheet glass at a temperature that is not softened by heating is clamped and Supported in the thickness direction, whereby the plate glass is elastically deformed to be in a bent state; and in the heating process, the plate glass is formed into a curved plate glass by heating the elastically deformed plate glass.

According to such a method, the sheet glass in a state in which the surface is hardened and deformed by heating and the surface is hard and hard to be damaged is elastically deformed and bent, and then heated to form a curved sheet glass. Therefore, it is possible to appropriately avoid the occurrence of the eccentricity or the like caused by the operation at the time of elastic deformation, and the surface of the plate glass is damaged at the portion in contact with the foreign object. As a result, it is possible to prevent defects or scratches remaining on the surface of the curved plate glass after molding as much as possible.

According to the curved plate glass formed by each of the above methods, since the surface is less likely to contain defects or scratches, it can be made into a high quality.

The touch panel having the above-mentioned curved plate glass and contact sensor can achieve good quality for the touch panel due to the use of high-quality curved plate glass.

Moreover, the molding die of the present invention invented in order to solve the above problems is a molding die for forming a flat plate glass into a curved plate glass having a curved shape, and has a concave curved surface and a convex curved surface; the concave curved surface is supported at two places spaced apart from each other in one side of the plate glass in the curved state; the convex curved surface is located between the two places One side of the one side of the panel is supported and faces the concave curved surface; and between the two curved surfaces, a curved forming space having a thickness larger than the thickness of the sheet glass is formed.

By using such a molding die, the flat plate glass is formed into a curved plate glass, and the same actions and effects as those described in the above-described method for molding the plate glass can be obtained.

As described above, according to the present invention, in the case where the flat plate glass is formed into a curved plate glass, it is possible to prevent defects or scratches from remaining on the surface of the curved plate glass after molding.

1‧‧‧Forming mould

11‧‧‧ Lower mold

11a‧‧‧ concave curved surface

R1‧‧‧ radius of curvature of the concave curved surface

12‧‧‧Upper mold

12a‧‧‧ convex curved surface

R2‧‧‧ radius of curvature of convex curved surface

21, 22‧‧‧ heat-resistant cloth

3‧‧‧ pathway

4‧‧‧pipe

G‧‧‧ plate glass

A, B‧‧‧ contact between the concave curved surface and the plate glass (heat-resistant cloth)

C‧‧‧Contact of convex curved surface and plate glass (heat resistant cloth)

S‧‧‧Bending forming space

Thickness of T‧‧‧bending space

O‧‧‧ Curvature Center

O’‧‧‧ Curvature Center

Fig. 1 is a longitudinal side sectional view showing a molding die used in the method for molding a sheet glass according to the first embodiment of the present invention.

Fig. 2 is a process view showing each step in the method for molding a sheet glass according to the first embodiment of the present invention.

Fig. 3 is a view showing a method of molding the sheet glass according to the second embodiment of the present invention.

Fig. 4 is a view showing a method of molding the sheet glass according to the third embodiment of the present invention.

Fig. 5 is a view showing a method of forming a sheet glass according to a fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Line description. First, a molding die used in the method for molding a sheet glass according to the first embodiment of the present invention will be described.

Fig. 1 is a longitudinal side sectional view showing a molding die for forming a flat plate glass into a curved plate glass having a curved shape. As shown in the figure, the molding die 1 includes a lower die 11 having a concave curved surface 11a and an upper die 12 having a convex curved surface 12a opposed to the concave curved surface 11a.

The concave curved surface 11a and the convex curved surface 12a are curved only with a certain curvature along the lateral direction (in a single direction) in Fig. 1, and the curvature centers O of the two curved surfaces 11a, 12a are identical to each other. That is, each of the two curved faces 11a, 12a is a partial cylindrical surface centered on the axis passing through the center of curvature O perpendicular to the plane of the paper. Further, the curvature radius of each of the curved surfaces 11a and 12a is defined as a concave curved surface 11a being R1 and a convex curved surface 12a being R2 (R1 > R2).

Between the two curved surfaces 11a and 12a, a curved forming space S for projecting the sheet glass G to be formed into a downward convex shape is formed. The thickness T of the curved forming space S is a certain thickness which is larger than the thickness of the sheet glass G. In addition, the "thickness T of the curved molding space S" is a distance between the concave curved surface 11a and the convex curved surface 12a along the normal line of the concave curved surface 11a (in the present embodiment, the two curved surfaces 11a, 12a) The distance between the phases is constant in the entire area of the curved forming space S).

Here, the thickness of the sheet glass G to be molded is preferably 2.0 mm or less, more preferably 1.5 mm or less, and most preferably 1.0 mm or less. Further, the lower limit of the thickness of the sheet glass G is 0.1 mm. Further, the plate glass G contains SiO ₂ : 50 to 80%, Al ₂ O ₃ : 5 to 25%, B ₂ O ₃ : 0 to 15%, and Na ₂ O as the glass component. 1 to 20%, K ₂ O: 0 to 10% of the glass is preferably a tempered glass plate after chemical strengthening.

Further, the thickness T of the curved molding space S is different from the thickness of the sheet glass G, and the thickness of the sheet glass G is preferably 1.0 mm or less, more preferably 0.5 mm or less, and most preferably 0.2 mm.

The sheet glass G positioned in the curved molding space S is sandwiched between the concave curved surfaces 11a in the thickness direction (two points A and B shown in Fig. 1), and One of the convex curved faces 12a between the two places (point C shown in Fig. 1) is supported in a curved state. Further, in the present embodiment, since the two curved faces 11a and 12a are curved only in the lateral direction, the concave curved faces 11a and the plate glass G are in line contact at points A and B, and at point C, The convex curved surface 12a is in line contact with the plate glass G. Further, point C is located in the middle of the point A and point B in the lateral direction.

In the present embodiment, the material of the molding die 1 (the lower die 11 and the upper die 12) is mullite (also called mullite). The mullite has a coefficient of thermal expansion of 55×10 ^-7 /K. In addition, in the present embodiment, the sheet glass G to be molded is T2X-1 manufactured by Nippon Electric Glass Co., Ltd. T2X-1 has a coefficient of thermal expansion of 91 × 10 ^-7 /K. Here, as the material of the molding die 1, in addition to the mullite, alumina, zircon, or a mixture thereof (for example, alumina-zirconia, zirconium corundum mullite) or the like may be used. In addition, in the case of using any of the materials, it is preferable that the value of the thermal expansion coefficient of the molding die 1 is in the range of 0.1 to 10 times the value of the thermal expansion coefficient of the sheet glass G. .

Next, a molding method of the sheet glass according to the first embodiment of the present invention will be described using the above-described molding die 1.

Fig. 2 is a process view showing each step in a method of molding a sheet glass for forming a flat plate glass into a curved plate glass having a curved shape. As shown in the figure, in the step of forming the curved sheet glass, the preheating step of the preheating mold 1 and the step of enclosing the sheet glass G in the molding die 1 and the heating forming mold 1 are included. The heating process of forming the curved plate glass in the inner sheet glass G, the cooling process of cooling the curved plate glass in the molding die 1, and the extraction process of taking out the curved plate glass from the molding die 1. Further, in the present embodiment, the movement of the molding die 1 during a part of the process or the movement of the molding die 1 in the process is carried out by a conveyor.

In the preheating step, the molding die 1 in a state in which the sheet glass G is not left empty is conveyed while being conveyed by the conveyor and passed through the inside of the preheating furnace to preheat the molding die 1. At this time, the preheating temperature of the molding die 1 is preferably in a temperature range of 200 ° C to 300 ° C.

In the nip process, the flat sheet glass G at a normal temperature (temperature range of 20 ± 15 ° C) is formed into a shape after preheating in the form described in the above description of the molding die 1. Inside the mold 1. At this time, as shown in Fig. 1, the plate glass G is held in the plate thickness direction. It is located at two places (point A, point B) which are located apart from each other between the concave curved faces 11a, and at one point (point C) of the convex curved faces 12a. Thereby, the flat plate glass G at normal temperature is elastically deformed and bent (only curved along the position in the lateral direction of FIG. 1).

More specifically, the sheet glass G enclosed in the molding die 1 (bending forming space S) is in the lateral direction (single direction) of Fig. 1 so as to be positioned on the upper surface of the central portion, imitating The bending is performed in such a manner that the convex curved surface 12a having a small radius of curvature (=R2) is relatively large. Further, the lower surface of the both end portions of the plate glass G is curved so as to have a concave curved surface 11a having a large radius of curvature (= R1). Therefore, the plate glass G is elastically deformed to have a smaller radius of curvature at the center portion and larger at both ends.

Further, in the present embodiment, the plate glass G at normal temperature is elastically deformed and bent in the embodiment, but it is not limited thereto, and the plate glass may be used in other temperature ranges. G is elastically deformed to be in a curved state. However, the temperature of the sheet glass G in the nip process is preferably such that the sheet glass G is maintained at a temperature which is not softened by heating, and is specifically maintained at 425 ° C or lower (corresponding to the sheet glass G). It is preferred that the viscosity is below 10 ²⁰ dPa‧s. Further, it is preferable to maintain it at 300 ° C or lower, and it is more preferable to maintain it at 200 ° C or lower. In the present embodiment, it is preferable to maintain it at normal temperature.

In the heating step, the molding die 1 in which the plate glass G which is elastically deformed is contained is conveyed while being conveyed on the conveyor, passes through the inside of the heating furnace, and passes through the molding die 1 to heat the plate glass G. Thereby, the elastically deformed sheet glass G is formed into a curved sheet glass. At this time, the viscosity of the sheet glass G (T2X-1) was a curved plate glass at a temperature range of 10 ⁸ dPa ‧ s to 10 ¹⁵ dPa ‧ s. Further, as a preferred temperature range, the viscosity of the sheet glass G is set to a temperature range of 10 ¹¹ dPa‧s to 10 ¹⁴ dPa‧s, and the optimum temperature range is such that the viscosity of the sheet glass G is 10 ^12.5. dPa‧s~10 ^13.5 dPa‧s temperature range. In such a temperature range, it is more preferable to form the curved plate glass in a temperature range of ±50 ° C based on the cold spot of the sheet glass G of 613 ° C. Further, it is preferably formed by a temperature range of ±20 ° C based on a cold spot of 613 ° C, and is preferably formed in a temperature range of ± 10 ° C based on a cold spot of 613 ° C. Further, the heating step may be carried out in a batch furnace in such a manner that the molding die 1 is arranged and heated.

In the cooling step, the curved plate glass is cooled while the curved plate glass is held inside the molding die 1. At this time, the temperature of the curved plate glass is lowered from the molding temperature to the temperature range of the strain point in order to reduce the internal strain of the glass.

In the take-out step, the curved plate glass contained in the molding die 1 is taken out from the molding die 1. Through the above steps, the curved plate glass is obtained. The curved plate glass is bent only in a single direction, and the radius of curvature is such that the radius of curvature is large at the center portion, and the curved plate glass is changed so that the radius of curvature at both end portions is small. Here, the curved plate glass in which the curvature radius is changed means that the maximum value of the radius of curvature of the curved plate glass is GR _max , and the minimum value of the radius of curvature is GR _min , which satisfies GR _min <(GR _max × 0.9). ) The relationship between the curved sheet glass.

In addition, the molding die 1 in a state in which the curved plate glass is taken out is formed into a curved plate glass in order to reinvigorate the new flat plate glass G, and is conveyed by the conveyor to return to the preheating step.

Hereinafter, the effects of the method for molding the sheet glass in the first embodiment of the present invention will be described.

According to the method for forming the sheet glass, the sheet glass G is sandwiched and supported at three places (point A and point B) of the concave curved surface 11a and one of the convex curved surfaces 12a (point C). The area of the portion of the surface of the sheet glass G that is in contact with the two curved surfaces 11a and 12a is suppressed to a small area, so that the curved sheet glass can be formed. Further, in the surface of the sheet glass G, the occurrence of defects or scratches can be substantially completely avoided in the portion where the two curved surfaces 11a and 12a are not in contact with each other.

Further, in this method, the sheet glass G in a state in which the surface is hard and not easily damaged is at a normal temperature lower than a temperature which is not softened by heating, and is elastically deformed to a state of being bent. Heated to form a curved plate glass. Therefore, it is possible to appropriately avoid the occurrence of a misalignment or the like due to the operation at the time of elastic deformation, and damage the surface of the sheet glass G at a portion in contact with the two curved surfaces 11a and 12a.

Further, since the curved forming space S having a large thickness is formed between the two curved faces 11a and 12a with respect to the plate thickness of the sheet glass G, it is possible to prevent the forming die 1 from exerting excessive pressure on the sheet glass G. . Further, since the curved sheet glass is formed in a temperature range of the sheet glass G having a viscosity of 10 ⁸ dPa ‧ s to 10 ¹⁵ dPa ‧ s, the curved sheet glass can be formed by minimal heating in the forming. That is, the occurrence of a problem caused by the softening of the sheet glass G can be suppressed as much as possible.

Further, when the value of the thermal expansion coefficient of the molding die 1 is in the range of 0.1 to 10 times the value of the thermal expansion coefficient of the sheet glass G, the thermal expansion coefficient due to the molding die 1 and the sheet glass G can be appropriately avoided. The difference in value is such a situation that a displacement deviation occurs between the two curved faces 11a, 12a and the sheet glass G due to the difference in the degree of expansion when both are expanded by heating. Therefore, it is possible to prevent the surface of the sheet glass G from being damaged by the displacement deviation at the portion where the two curved surfaces 11a and 12a are in contact with the sheet glass G.

As described above, according to the method of forming the sheet glass, it is possible to prevent defects or scratches on the surface of the curved sheet glass after forming as much as possible. In addition, according to the method of forming the sheet glass, the actions and effects as described below can also be obtained.

That is, in the present method, since the sheet glass G can be heated to a minimum temperature necessary for molding, the electric power consumed by the heating can be reduced. Further, in the present method, as described above, since the occurrence of a problem caused by the softening of the sheet glass G can be suppressed as much as possible, it is possible to appropriately prevent the occurrence of defects on the surface of the curved sheet glass after the forming or Scars. Therefore, from the viewpoint of preventing damage to the surface of the sheet glass G, it is difficult to receive the processing precision of the surface of the two curved faces 11a, 12a of the forming mold 1, or for the forming die. The material selection with 1 is restricted. As a result, the production of the molding die 1 can be performed at low cost. According to these characteristics, the manufacturing cost of the curved plate glass can be reduced.

Further, in the preheating step, since the molding die 1 (the lower die 11 and the upper die 12) that sandwiches and supports the sheet glass G is heated in advance, it is also possible to shorten the time during which the heater glass G is heated to the molding temperature. As a result, the production efficiency of the curved sheet glass can be improved. Further, in the case of the heating process described in the embodiment, the length of the heating furnace can be shortened.

Further, in the present method, in the holding step, the sheet glass G at normal temperature may be placed on the forming mold 1 (the lower mold 11 and the upper mold 12). In this case, the sheet glass G at a low temperature is placed on the forming mold 1 as compared with the case where the softened sheet glass is placed. As a result, it is not easy to damage the equipment for placing the sheet glass G, and the like, so that the life of the equipment can be extended. Further, since the sheet glass G is at a normal temperature, the sheet glass G can be placed on the forming mold 1 by manual work without using equipment or the like.

Further, when the thickness T of the curved molding space S is different from the thickness of the sheet glass G, when the thickness is set to 0.2 mm to 1.0 mm, the curved surfaces 11a and 12a of the concave curved surface 11a and the convex curved surface 12a are formed. The sheet glass G can be held and supported in a stable state. Therefore, in the case where the curved plate glass is mass-produced, it is possible to suppress the occurrence of a jagged state in which the plurality of curved plate glasses are generated at the time of completion of the processing.

Moreover, the bending formed by the forming method of the sheet glass Since the plate glass is hard to contain defects or scratches on its surface, it can be made into a high quality. Further, when the sheet glass G has a preferable composition as described above, it is also possible to manufacture a curved sheet glass having high strength. Further, when the touch panel including the curved plate glass and the contact sensor is manufactured, the high quality curved plate glass can be used, and the touch panel can also achieve good quality.

Hereinafter, a method of molding the sheet glass according to another embodiment of the present invention will be described. In the description of the method for molding the sheet glass according to each of the following embodiments, the constituent elements having the same function or the same shape as the constituent elements described in the method for molding the sheet glass according to the first embodiment described above are provided. The same reference numerals are used to designate the drawings in the respective embodiments, and the overlapping description will be omitted. Further, in the following embodiments, only differences from the first embodiment will be described.

Fig. 3 is a view showing a method of molding the sheet glass according to the second embodiment of the present invention. As shown in the figure, the method of forming the sheet glass according to the second embodiment differs from the method of forming the sheet glass according to the first embodiment in that the concave curved surface 11a and the sheet are formed in the holding step. Between the lower surfaces of the glass G and between the convex curved surface 12a and the upper surface of the plate glass G, the heat-resistant cloths 21 and 22 which are sheet-like heat-resistant members are provided therebetween.

In the present embodiment, each of the heat-resistant fabrics 21 and 22 is made of glass fiber. Here, as the heat-resistant fabrics 21 and 22, in addition to the woven glass fiber, it is also possible to use alumina fibers or metal fibers, carbon fibers, or glass fibers or alumina fibers. Dimensions and carbon fibers are crimp-formed into a sheet shape. The heat-resistant fabrics 21 and 22 cover the entire area of the lower surface and the upper surface of the elastically deformed sheet glass G, respectively. Thereby, the sheet glass G is passed through the heat-resistant cloths 21, 22 at two places (point A, point B) of the concave curved surface 11a, and one point (point C) of the convex curved surface 12a, and is sandwiched and supported by the sheet thickness. direction.

Further, the thickness T of the curved molding space S is different from the total thickness of the three layers composed of the plate glass G and the two heat-resistant fabrics 21 and 22, and the difference is preferably 1.0 mm or less regardless of the total thickness of the three layers. Preferably, it is 0.5 mm or less, and most preferably 0.2 mm.

According to the method for forming a sheet glass according to the second embodiment, the same actions and effects as those of the sheet glass forming method according to the first embodiment described above can be obtained.

Further, in the method of forming the sheet glass of the second embodiment, by providing the heat-resistant cloths 21, 22, the surface of the sheet glass G can be prevented from directly contacting the two curved surfaces 11a, 12a, and the protection can be more safely protected. The surface of the sheet glass G is free from defects or damage. Therefore, it is possible to more appropriately prevent the surface from being scratched or scratched on the surface of the curved plate glass after the forming.

Fig. 4 is a view showing a method of forming a sheet glass according to a third embodiment of the present invention. As shown in the figure, the method of forming the sheet glass according to the third embodiment differs from the method of forming the sheet glass according to the first embodiment in the molding die 1 used for forming the sheet glass G (below). In the mold 11 and the upper mold 12), the radius of curvature R1 of the concave curved surface 11a and the radius of curvature R2 of the convex curved surface 12a are not constant (and are not curved with a certain curvature).

The two curved faces 11a, 12a are in the lateral direction, have a minimum curvature at the central portion thereof, and gradually become larger as they move from the central portion toward the end portion side. That is, the curvature radii R1, R2 of the two curved faces 11a, 12a are the largest at the center portion and the smallest at both ends. Therefore, moving from the center portion toward the end side, as shown in Fig. 4, the curvature center O' is closer to the curved forming space S.

Further, the radius of curvature R1 of the point A and the point B located on the concave curved surface 11a is a radius of curvature of the upper surface of the sheet glass G supported by the points A and B, which is equal to the position. The curvature radius R2 (the maximum value of R2) of the point C of the convex curved surface 12a is adjusted. Here, the magnitude of the radius of curvature R1 of the concave curved surface 11a located at points A and B, and the radius of curvature R2 of the convex curved surface 12a located at point C are the dimensions of the upper surface of the upper glass G or the plate. The various conditions such as the thickness of the glass G vary. Therefore, it is preferable that the size of the radius of curvature R1 at point A and point B and the radius of curvature R2 at point C are appropriately selected in advance by trial or simulation.

According to the method for forming a sheet glass according to the third embodiment, the same actions and effects as those of the sheet glass forming method according to the first embodiment described above can be obtained. Moreover, the curved sheet glass formed by the method for forming the sheet glass is a curved sheet glass which is bent only in a single direction and which is curved at a substantially constant radius of curvature (a substantially constant curvature). Further, the term "curved plate glass which is curved at a substantially constant radius of curvature" means that the maximum value of the radius of curvature of the curved plate glass is GR _max and the minimum value of the radius of curvature is GR _min , which satisfies GR _min ≧ Curved plate glass in relation to (GR _max × 0.9).

Fig. 5 is a view showing a method of forming a sheet glass according to a fourth embodiment of the present invention. As shown in the figure, the method of forming the sheet glass according to the fourth embodiment differs from the method of forming the sheet glass according to the first embodiment in that three molds penetrating the forming mold 1 are formed in the molding die 1. At the point of the passage 3 of the refrigerant and when the heating step is performed, the refrigerant flowing in the passage 3 is cooled by the point A and the point B located on the concave curved surface 11a of the molding die 1 and at the convex curved surface 12a. This point is supported by each part of the plate glass G supported by point C. Further, in the first embodiment described above, the heating process is performed by conveying the molding die 1 while passing through the inside of the heating furnace by the conveyor. However, in the present embodiment, only the molding die 1 is placed on the heating. The heating process is carried out in the state of the furnace.

The three passages 3 each pass through the forming die 1, and both ends thereof are formed inside the pipe 4 which extends outside the heating furnace. Each of the three ducts 4 forming the respective passages 3 extends through the portion of the forming die 1 in a direction perpendicular to the fifth drawing surface, and passes through point A or point B of the concave curved surface 11a. Or located near the point C of the convex curved surface 12a. Moreover, each of the pipes 4 is connected to a supply device (for example, a pump or the like) of the refrigerant provided outside the heating furnace, and when the heating process is performed, the refrigerant supplied from the device flows through the passage 3.

Here, as the refrigerant, air, steam, water, liquid nitrogen, or the like can be used. Also, as the material of the pipe 4, it is also possible A metal such as stainless steel or a ceramic material such as alumina is used, but it is preferable to use a metal having high thermal conductivity from the viewpoint of cooling efficiency. Further, it is preferable that the passage 3 is at a distance from each of the points A, B, and C described above, and the distance closest to the points is as short as possible within a range that allows the mechanical strength of the molding die 1 to be as short as possible. It is 3mm~15mm.

According to the method for forming a sheet glass according to the fourth embodiment, the same actions and effects as those of the sheet glass forming method according to the first embodiment described above can be obtained. Further, according to the method for forming the sheet glass, since each portion of the sheet glass G supported by the points A, B, and C is cooled by the refrigerant, it is possible to prevent the portions from being softened by heating. It is easy to maintain in a state that is hard and not easily damaged. As a result, it is possible to more appropriately prevent defects or scratches from remaining on the surface of the curved plate glass after molding.

Further, in the method of molding the sheet glass according to the third and fourth embodiments, the heat-resistant cloth may be provided on the sheet glass G in the holding step, similarly to the method of forming the sheet glass according to the second embodiment. The state between the lower surface and the concave curved surface 11a, and between the upper surface of the plate glass G and the convex curved surface 12a.

Here, the molding method or the molding die of the sheet glass of the present invention is not limited to the form or configuration described in the above embodiments. For example, the molding die used in each of the above-described embodiments has a configuration in which a convex curved forming space facing downward is formed. However, a convex curved forming space facing upward may be formed as a configuration. Further, in the molding die used in each of the above embodiments, the thickness of the curved molding space formed between the concave curved surface and the convex curved surface is constant, but the thickness is constant. The thickness can also be formed in a continuous manner.

Further, in the first, second, and fourth embodiments, the curvature radius of the concave curved surface and the convex curved surface are different from each other in the embodiment, and the forming radius of curvature is formed. The shape of the curved plate glass that is different from each other. However, the radius of curvature of the formed curved plate glass can be adjusted in addition to the adjustment of the radius of curvature of the concave curved surface and the convex curved surface. That is, in the three of the curvature radius of the concave curved surface, the radius of curvature of the convex curved surface, and the distance between the two curved surfaces, the radius of curvature of the formed curved plate glass can be adjusted by adjusting at least one of them . For example, when it is desired to adjust the distance between the two curved faces, the separation distance can be easily adjusted by providing a spacer or the like between the lower die and the upper die of the molding die. Thereby, the radius of curvature of the formed curved plate glass can be adjusted.

Further, in the fourth embodiment described above, the passage for passing the refrigerant is formed by the pipe passing through the forming die, but the invention is not limited thereto. For example, a through hole penetrating the molding die may be formed in the molding die, and a refrigerant may be circulated in the through hole. That is, the via may be formed by the through holes. Further, when the passage is formed by a pipe that passes through the molding die, the direction in which the pipe passes through the molding die can be any direction, and the number of the pipes can be any number.

Further, in each of the above embodiments, the curved plate glass is formed by using a molding die, but the invention is not limited thereto. example For example, using three fire-resistant bars, two of them are arranged in parallel, and are supported in line contact manner at two places spaced apart from each other on one side of the plate glass, and are arranged in parallel with the above two. The other one supports the one side of the other side of the board at a position between the two places in a line contact manner. Further, the plate glass is sandwiched in the plate thickness direction at three places, and the plate glass is elastically deformed to be in a bent state. Then, by heating the elastically deformed sheet glass, it is possible to obtain a curved sheet glass.

1‧‧‧Forming mould

11‧‧‧ Lower mold

11a‧‧‧ concave curved surface

12‧‧‧Upper mold

12a‧‧‧ convex curved surface

R1‧‧‧ radius of curvature of the concave curved surface

R2‧‧‧ radius of curvature of convex curved surface

G‧‧‧ plate glass

A, B‧‧‧ contact between concave curved surface and plate glass

C‧‧‧Contact of convex curved surface and plate glass

S‧‧‧Bending forming space

Thickness of T‧‧‧bending space

O‧‧‧ Curvature Center

Claims (16)

A method for forming a sheet glass is a method of forming a flat sheet glass into a curved sheet glass, and is characterized in that the step of clamping is performed such that the one side of one side of the sheet glass is spaced apart from each other Two places, and one place on the other side of the board between the two places, the plate glass is clamped and supported in the plate thickness direction, thereby elastically deforming the plate glass to be in a bent state; and heating In the step, the plate glass is formed into the curved plate glass by heating the plate glass which is elastically deformed. The method for forming a sheet glass according to claim 1, wherein a forming mold having a concave curved surface and a convex curved surface facing the concave curved surface and having a curved surface is used. Forming a curved forming space having a thickness larger than a thickness of the plate glass; and in the clamping step, the plate glass is sandwiched and supported at two places of the concave curved surface and the convex curved surface One place. The method for forming a sheet glass according to the first or second aspect of the invention, wherein the sheet glass is maintained at a temperature that is not softened and deformed by heating. The method for forming a sheet glass according to claim 2, wherein the concave curved surface and the convex curved surface are curved in the same single direction. The method for forming a sheet glass according to the second aspect of the invention, wherein the thickness of the curved forming space is set to be relative to the plate glass The glass is also thick to a certain thickness of 0.2 mm to 1.0 mm. The method for forming a sheet glass according to claim 1 or 2, wherein in the heating step, in a temperature range of 10 ⁸ dPa‧s to 10 ¹⁵ dPa‧s, the viscosity of the sheet glass is The above plate glass is formed into the above-mentioned curved plate glass. The method for forming a sheet glass according to the first or second aspect of the invention, wherein the sheet glass is formed in a temperature range of ±50° C. based on a cold spot of the sheet glass in the heating step. For the above curved plate glass. The method for molding a sheet glass according to claim 2, wherein a preheating step of preheating the forming mold is performed before the holding step. The method for forming a sheet glass according to claim 2, wherein at least one of a radius of curvature of the concave curved surface, a radius of curvature of the convex curved surface, and a distance between the two curved surfaces is adjusted, To adjust the radius of curvature of the above curved plate glass. The method for forming a sheet glass according to the second aspect of the invention, wherein the value of the coefficient of thermal expansion of the forming mold is within a range of 0.1 to 10 times the value of the coefficient of thermal expansion of the sheet glass. The sheet glass forming method according to the second aspect of the invention, wherein the sheet-like heat-resistant member is provided between the concave curved surface and one of the plate glasses, and The convex curved surface is between the other plate surface of the above plate glass. Forming party of the sheet glass as described in claim 2 In the heating step, the refrigerant is passed through a passage penetrating through the molding die, and the above-mentioned molding die is supported by two places of the concave curved surface and one of the convex curved surfaces. Each part of the sheet glass is cooled. A method for forming a sheet glass is a method of forming a flat plate glass into a curved plate glass having a curved shape, and is characterized in that: a clamping step is performed at a temperature which is not softened by heating. The plate glass is clamped and supported in a plate thickness direction, whereby the plate glass is elastically deformed to be in a bent state; and a heating process is performed by heating the elastically deformed plate glass to form the plate glass into the curved plate glass . A curved sheet glass, which is formed by the method for forming a sheet glass according to any one of claims 1 to 13. A touch panel comprising: the curved plate glass according to claim 14 and a contact sensor. A forming die is a forming die for forming a flat plate glass into a curved plate glass having a curved shape, and has a concave curved surface and a convex curved surface, which is in a curved state The two sides of the plate glass are supported by two spaced apart sides; the convex curved surface is supported at a position on the other side of the plate between the two places, and Concave curved faces facing each other; Further, between the two curved faces, a curved forming space having a thickness larger than the plate thickness of the plate glass is formed.