JP6451320B2 - Sheet glass forming method - Google Patents

Description

  The present invention relates to a plate glass forming method for forming a flat plate glass into a curved plate glass having a curved shape, and a forming die for forming the curved plate glass.

  In recent years, mobile devices such as smartphones and tablet PCs are rapidly spreading. As the plate glass used for the touch panel of these devices, in addition to the flat plate glass that has been conventionally employed, for example, a curved plate glass having a curved surface formed with a certain radius of curvature may be employed. is there.

  An example of a method for forming such a curved plate glass is disclosed in Patent Document 1. In this document, a flat plate glass held by a heat-resistant sheet is heated and softened, and then the entire surface (one surface) of the plate glass is formed on the convex curved surface formed in the mold through the heat-resistant sheet. It describes that a curved plate glass is formed by clinging.

JP 2012-116692 A

  However, when a curved plate glass is formed by the method disclosed in Patent Document 1, there are the following problems to be solved. That is, in the forming method disclosed in the same document, the plate glass clinging to the convex curved surface is softened by heating, and thus the surface thereof is in a state of being extremely easily deformed.

  For this reason, the minute unevenness contained in the convex curved surface is transferred to the surface of the plate glass through the heat-resistant sheet, or the surface of the plate glass is damaged due to the displacement caused by the operation when the sheet is attached. was there. As a result, dot-like, convex or concave defects or scratches called pits remain on the surface of the curved plate glass after molding, leading to a situation in which the quality of the curved plate glass is greatly deteriorated.

  This invention made | formed in view of the said situation makes it a technical subject to prevent the defect on the surface of the curved plate glass after shaping | molding, and the residue of a damage | wound as much as possible, when shape | molding flat plate glass into curved plate glass. .

  The method according to the present invention devised to solve the above-described problems is a method of forming a flat plate glass into a curved plate glass having a curved shape. A sandwiching step of elastically deforming the plate glass into a curved state by sandwiching and supporting the plate glass in the plate thickness direction at one place on the other side located between the places, and heating the elastically deformed plate glass Thus, it is characterized by including a heating step of forming the plate glass into a curved plate glass.

  According to such a method, since the plate glass is sandwiched and supported at three locations of two locations on the one surface side and one location on the other surface side, the surface (one surface and the other surface) of the plate glass is an external object. The curved plate glass can be formed while suppressing the area of the portion in contact with the sheet to be small. And about the site | part which does not contact an external object among the surfaces of plate glass, generation | occurrence | production of a defect and a damage | wound can be avoided substantially completely. As a result, it is possible to prevent defects and scratches on the surface of the curved plate glass after forming as much as possible.

  In the above method, molding having a concave curved surface and a convex curved surface facing the concave curved surface, and a curved molding space having a large thickness with respect to the plate thickness of the glass sheet is formed between both curved surfaces. It is preferable to sandwich and support the plate glass at two locations on the concave curved surface and one location on the convex curved surface using a mold.

  In this way, since a curved forming space having a thickness larger than the thickness of the plate glass is formed between the two curved surfaces, it is possible to avoid an excessive pressure from acting on the plate glass from the mold. It becomes possible. Further, in this method, since the plate glass is sandwiched and supported at three locations of two concave curved surfaces and one convex curved surface, the area of the portion where the curved surfaces and the surface of the plate glass are in contact with each other is small. It is suppressed. Therefore, it is possible to prevent the surface of the plate glass from being damaged as much as possible.

In the above method, it is preferable to maintain the plate glass at a temperature at which it is not softened and deformed by heat in the sandwiching step. Here, the “temperature at which softening deformation does not occur due to heat” specifically means a temperature equal to or lower than the temperature corresponding to 10 ²⁰ dPa · s (hereinafter the same). The temperature of the plate glass in the clamping step is more preferably maintained at 300 ° C. or lower, more preferably 200 ° C. or lower, and most preferably maintained at room temperature (20 ± 15 ° C. temperature range).

  If it does in this way, in the clamping process, since it exists in the temperature which plate glass does not soften and deform | transform by heat, the surface of plate glass can be hold | maintained in the state which is hard and hard to be damaged. Thereby, it becomes possible to avoid suitably that the surface of a plate glass is damaged by the shift | offset | difference etc. with the operation | movement at the time of making it elastically deform. Further, according to this method, when a curved plate glass is formed using a forming die, the plate glass at a temperature at which it is not softened and deformed by heat can be placed on the forming die. Therefore, compared with the case where the softened plate glass is placed, the plate glass at a low temperature is placed on the mold. As a result, the equipment for mounting the plate glass is less likely to be damaged, and the life of the equipment can be extended. Furthermore, when the plate glass is at room temperature, the plate glass can be placed on the mold by a manual operation by a person.

  In the above method, the concave curved surface and the convex curved surface may be curved along the same single direction.

  If it does in this way, it will become possible to shape | curve the curved plate glass of the shape curved only in the single direction.

  In said method, it is preferable to make thickness of curve shaping | molding space into the constant thickness 0.2mm-1.0mm thick with respect to plate glass.

  If it does in this way, both curved surfaces of a concave curved surface and a convex curved surface can pinch | interpose and support a plate glass in the stable state. Therefore, in the case of mass production of curved plate glass, it is possible to suppress the occurrence of a situation in which a finish variation occurs between a plurality of curved plate glasses.

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

  If it does in this way, when shape | molding plate glass to curved plate glass, the favorable moldability of the said plate glass and the effect which prevents the defect and the residue of a damage | wound on the surface of curved plate glass can be made to make compatible suitably.

  In the above method, in the heating step, it is preferable that the plate glass is formed into a curved plate glass in a temperature range of ± 50 ° C. based on the annealing point of the plate glass.

  If it does in this way, shaping | molding of a curved plate glass will be performed only by the minimum heating required for shaping | molding. That is, it is possible to suppress the occurrence of defects due to the softening of the plate glass as much as possible. Therefore, it is possible to more suitably prevent defects and scratches from remaining on the surface of the curved plate glass after molding. Thereby, from the viewpoint of preventing the surface of the plate glass from being damaged, the processing accuracy of the surfaces of the curved surfaces of the mold and the selection of the material of the mold are not easily restricted. As a result, there is an advantage that the mold can be manufactured at low cost. Moreover, since it is sufficient that the glass sheet can be heated to the minimum temperature necessary for molding, the power consumed with the heating is reduced. As a result, the manufacturing cost can be reduced.

  In said method, it is preferable to implement the preheating process which heats a shaping | molding die previously before a clamping process.

  In this way, the mold for supporting the sheet glass in between is heated in advance, so that the time for heating the sheet glass to the molding temperature can be shortened. Thereby, the production efficiency of curved plate glass can be improved.

  In the above method, the curvature radius of the curved plate glass may 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 both curved surfaces. Good. Here, the “curvature radius of the curved plate glass” means not only the curvature radius when the curved plate glass is curved with a constant curvature, but also the curvature radius when the curved plate glass is curved in a continuously changing state. (The same applies to the radius of curvature of the concave curved surface and the radius of curvature of the convex curved surface).

  If it does in this way, it will become possible to manufacture various curved plate glass, such as a curved plate glass which has a substantially constant curvature radius, and a curved plate glass in which a curvature radius changes, for example.

  In said method, it is preferable that the value of the thermal expansion coefficient of a shaping | molding die exists in the range of 0.1 time-10 times the value of the thermal expansion coefficient of plate glass.

  In this way, due to the difference in the value of the thermal expansion coefficient between the mold and the sheet glass, when both expand due to heating, a situation may occur in which a difference occurs between the two due to the difference in the degree of expansion. Can be suitably avoided. As a result, it is possible to prevent the surface of the plate glass from being damaged due to the shift at the site where both are in contact.

  In the above method, it is preferable to interpose a sheet-like heat-resistant member between the concave curved surface and one surface of the plate glass and between the convex curved surface and the other surface of the plate glass in the clamping step.

  If it does in this way, it will avoid that the surface of a plate glass and a shaping | molding die contact directly by intervention of a sheet-like heat-resistant member, and the surface of a plate glass will be protected more safely from generation | occurrence | production of a defect and a damage | wound. Thereby, it is possible to more suitably prevent defects and scratches from remaining on the surface of the curved plate glass after molding.

  In the above method, in the heating step, the two portions of the concave curved surface in the molding die and each part of the plate glass supported by one location of the convex curved surface are cooled by the refrigerant flowing through the passage penetrating the molding die. Also good.

  In this way, since each part of the plate glass supported by both curved surfaces is cooled by the refrigerant, it is possible to suppress softening of these parts by heat, and it is easy to maintain a hard and scratch-resistant state. Become. As a result, it is possible to more suitably prevent defects and scratches from remaining on the surface of the curved plate glass after molding.

  The method according to the present invention, which was created to solve the above problems, is a method of forming a flat plate glass into a curved plate glass having a curved shape. It is characterized by including a sandwiching step of elastically deforming the plate glass into a curved state by sandwiching and supporting, and a heating step of forming the plate glass into the curved plate glass by heating the elastically deformed plate glass.

  According to such a method, a glass sheet that is at a temperature that is not softened and deformed by heat and whose surface is hard and hard to be damaged is elastically deformed into a curved state, and then heated to form a curved glass sheet. For this reason, it becomes possible to avoid suitably damaging the surface of a plate glass in the site | part which contacts an external object by the shift | offset | difference etc. accompanying the operation | movement at the time of elastically deforming. As a result, it is possible to prevent defects and scratches on the surface of the curved plate glass after forming as much as possible.

  The curved plate glass formed by each of the methods described above can be of high quality because the surface thereof is less likely to contain defects and scratches.

  Since the touch panel provided with the curved plate glass and the touch sensor uses a high-quality curved plate glass, the touch panel can also have good quality.

  In addition, a molding die according to the present invention created to solve the above problems is a molding die for molding a flat plate glass into a curved plate glass having a curved shape, on one side of the curved plate glass. A concave curved surface that supports two locations spaced apart from each other, and a convex curved surface that supports one location on the other side located between the two locations and faces the concave curved surface. It is characterized in that a curved forming space having a thickness larger than the thickness of the plate glass is formed between them.

  If a flat plate glass is formed into a curved plate glass using such a mold, it is possible to obtain the same actions and effects as those already described for the method for forming the above plate glass.

  As described above, according to the present invention, when a flat plate glass is formed into a curved plate glass, it is possible to prevent defects and scratches on the surface of the curved plate glass after forming as much as possible.

It is a vertical side view which shows the shaping | molding die used for the shaping | molding method of the plate glass which concerns on 1st embodiment of this invention. It is process drawing which shows each process in the shaping | molding method of the plate glass which concerns on 1st embodiment of this invention. It is a figure which shows the shaping | molding method of the plate glass which concerns on 2nd embodiment of this invention. It is a figure which shows the shaping | molding method of the plate glass which concerns on 3rd embodiment of this invention. It is a figure which shows the shaping | molding method of the plate glass which concerns on 4th embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, the shaping | molding die used for the shaping | molding method of the plate glass which concerns on 1st embodiment of this invention is demonstrated.

  FIG. 1 is a longitudinal side view showing a mold for forming a flat plate glass into a curved plate glass having a curved shape. As shown in the figure, the mold 1 includes a lower mold 11 having a concave curved surface 11a, and an upper mold 12 having a convex curved surface 12a facing the concave curved surface 11a.

  The concave curved surface 11a and the convex curved surface 12a are curved with a constant curvature only along the lateral direction in FIG. 1 (along a single direction), and the curvature centers O of both the curved surfaces 11a and 12a are the same. Has been. That is, each of the curved surfaces 11a and 12a is a partial cylindrical surface centering on an axis passing through the center of curvature O in a direction perpendicular to the paper surface. And the magnitude | size of the curvature radius of both the curved surfaces 11a and 12a is set to R1 for the concave curved surface 11a, and R2 for the convex curved surface 12a, respectively (R1> R2).

  Between the curved surfaces 11a and 12a, a downwardly curved curved molding space S that encloses the glass sheet G to be molded is formed. The thickness T of the curved forming space S is a constant thickness larger than the thickness of the plate glass G. The “thickness T of the curved forming 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 this embodiment, both curved curves The distance at which the surfaces 11a and 12a are separated is constant throughout the curved molding space S).

Here, the thickness of the plate 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. And the lower limit of the thickness of the plate glass G is 0.1 mm. Further, the glass sheet G is a glass composition including, in _{mass%, SiO 2: 50~80%,} Al 2 O 3: 5~25%, B 2 O 3: 0~15%, Na 2 O: 1~20% , K ₂ O: A tempered glass plate obtained by chemically strengthening glass containing 0 to 10% is preferable.

  In addition, the dimensional difference between the thickness T of the curved forming space S and the thickness of the plate glass G is preferably 1.0 mm or less, more preferably 0.5 mm or less, and most preferably, regardless of the thickness of the plate glass G. Is 0.2 mm.

  The plate glass G in the curved forming space S has two locations (point A and point B shown in FIG. 1) spaced apart from each other on the concave curved surface 11a, and one location on the convex curved surface 12a located between the two locations. (Point C shown in FIG. 1) and sandwiched in the thickness direction and supported in a curved state. In the present embodiment, since both the curved surfaces 11a and 12a are curved only along the lateral direction, the concave curved surface 11a and the plate glass G are in line contact at the points A and B, and C At a point, the convex curved surface 12a and the glass sheet G are in line contact. Further, the point C is located between the points A and B in the horizontal direction.

In this embodiment, mullite is adopted as the material of the mold 1 (the lower mold 11 and the upper mold 12). Mullite has a coefficient of thermal expansion of 55 × 10 ⁻⁷ / K. Moreover, in this embodiment, the plate glass G used as the object of shaping | molding is T2X-1 by Nippon Electric Glass. T2X-1 has a coefficient of thermal expansion of 91 × 10 ⁻⁷ / K. Here, as a material of the mold 1, alumina, zircon, a mixture thereof (for example, alumina zircon, zircon mullite) and the like can be employed in addition to mullite. In addition, even if it is a case where any material is employ | adopted as the shaping | molding die 1, the value of the thermal expansion coefficient of the shaping | molding die 1 exists in the range of 0.1 time-10 times the value of the thermal expansion coefficient of the plate glass G. Preferably there is.

  Next, the shaping | molding method of the plate glass which concerns on 1st embodiment of this invention using said shaping | molding die 1 is demonstrated.

  FIG. 2 is a process diagram showing each process for forming a flat plate glass into a curved plate glass having a curved shape. As shown in the figure, the steps for forming the curved plate glass include a preheating step for preheating the forming die 1, a sandwiching step for enclosing the plate glass G in the forming die 1, and a plate glass G in the forming die 1. A heating step for heating and forming the curved plate glass, a cooling step for cooling the curved plate glass in the mold 1, and an extraction step for taking out the curved plate glass from the mold 1 are included. In the present embodiment, the movement of the mold 1 between some processes or the movement of the mold 1 within the process is performed by conveyance by a conveyor.

  In the preheating step, the empty mold 1 that does not contain the plate glass G is passed through the preheating furnace while being conveyed by a conveyor, and the mold 1 is preheated. At this time, the preheating temperature of the mold 1 is preferably in the temperature range of 200 ° C to 300 ° C.

  In the sandwiching step, a flat plate glass G at a normal temperature (temperature range of 20 ± 15 ° C.) is included in the preheated mold 1 in the manner already described in the description of the mold 1 described above. At this time, as already shown in FIG. 1, the plate glass G is formed by the two portions (point A and point B) of the concave curved surface 11 a in the mold 1 and the single portion (point C) of the convex curved surface 12 a. It is sandwiched and supported in the thickness direction. Thereby, the flat plate glass G at room temperature is elastically deformed into a curved state (curved only along the lateral direction in FIG. 1).

  More specifically, the glass sheet G contained in the mold 1 (curved molding space S) has a relatively high curvature radius (= R2) at the upper surface in the center in the lateral direction (single direction) of FIG. It curves so as to follow the small convex curved surface 12a. Further, the lower surfaces of both ends of the glass sheet G are curved so as to follow the concave curved surface 11a having a relatively large radius of curvature (= R1). Therefore, the plate glass G is elastically deformed so that the radius of curvature is small at the center and large at both ends.

In the present embodiment, the glass sheet G at room temperature is elastically deformed into a curved state. However, the present invention is not limited to this, and the glass sheet G is curved in another temperature range. It may be elastically deformed. However, the temperature of the plate glass G in the clamping step is preferably maintained at a temperature at which the plate glass G is not softened and deformed by heat. Specifically, the temperature is 425 ° C. or less (the temperature at which the viscosity of the plate glass G corresponds to 10 ²⁰ dPa · s). Or less). And it is more preferable to maintain at 300 degrees C or less, It is more preferable to maintain at 200 degrees C or less, It is most preferable to maintain at normal temperature like this embodiment.

In the heating process, the mold 1 containing the elastically deformed sheet glass G is passed through the heating furnace while being conveyed by the conveyor, and the sheet glass G is heated via the mold 1. Thereby, the elastically deformed plate glass G is formed into a curved plate glass. At this time, the curved plate glass is formed in a temperature range in which the viscosity of the plate glass G (T2X-1) is 10 ⁸ dPa · s to 10 ¹⁵ dPa · s. A more preferable temperature range is a temperature range in which the viscosity of the plate glass G is 10 ¹¹ dPa · s to 10 ¹⁴ dPa · s, and the most preferable temperature range is a viscosity of the plate glass G of 10 ^12.5 dPa · s. The temperature range is s to 10 ^13.5 dPa · s. In such a temperature range, it is preferable that the curved plate glass is molded in a temperature range of ± 50 ° C. with reference to the annealing point 613 ° C. of the plate glass G. More preferably, the molding is performed in a temperature range of ± 20 ° C. based on the annealing point 613 ° C., and most preferably the molding is performed in a temperature range of ± 10 ° C. based on the annealing point 613 ° C. Moreover, you may implement this heating process in the aspect which puts the shaping | molding die 1 in a batch furnace, and heats it.

  In the cooling step, the curved plate glass is cooled while being included in the mold 1. At this time, the temperature of the curved plate glass is slowly lowered in the temperature range from the molding temperature to 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 mold 1 is taken out from the mold 1. A curved plate glass is obtained through the above steps. This curved plate glass is a curved plate glass that is curved only along a single direction and has a radius of curvature that is large at the center and small at both ends. Here, the curved plate glass in which the radius of curvature changes is defined as GR _min <(GR _max × 0.9), where GR _max is the maximum value of the radius of curvature of the curved plate glass and GR _min is the minimum value of the radius of curvature. It means the curved plate glass that satisfies the relationship.

  The empty mold 1 from which the curved plate glass has been taken out is transported by a conveyor and returned to the preheating step in order to newly encapsulate the flat plate glass G and form it into the curved plate glass.

  Hereinafter, the operation and effect of the glass sheet forming method according to the first embodiment of the present invention will be described.

  According to this glass sheet forming method, the glass sheet G is sandwiched and supported at three locations, that is, two locations (point A, point B) of the concave curved surface 11a and one location (point C) of the convex curved surface 12a. Thus, the curved plate glass can be formed while the surface of the plate glass G suppresses the area of the portion in contact with both the curved surfaces 11a and 12a to be small. And about the site | part which does not contact both the curved surfaces 11a and 12a among the surfaces of the plate glass G, generation | occurrence | production of a defect and a damage | wound can be avoided substantially completely.

  Further, in this method, the plate glass G, which is at a room temperature lower than the temperature at which it is not softened and deformed by heat and whose surface is hard and hard to be damaged, is elastically deformed into a curved state and then heated to bend the curved plate glass. To form. For this reason, it becomes possible to avoid suitably that the surface of the plate glass G is damaged at a portion in contact with both the curved surfaces 11a and 12a due to a shift caused by an operation when elastically deforming.

Further, since a curved molding space S having a thickness larger than the thickness of the plate glass G is formed between the curved surfaces 11a and 12a, it is avoided that an excessive pressure acts on the plate glass G from the mold 1. It becomes possible to do. Further, since the curved plate glass is formed in a temperature range in which the viscosity of the plate glass G is 10 ⁸ dPa · s to 10 ¹⁵ dPa · s, the curved plate glass is formed with only the minimum heating necessary for forming. That is, it is possible to suppress the occurrence of defects due to the softening of the plate glass G as much as possible.

  In addition, when the value of the coefficient of thermal expansion of the mold 1 is in the range of 0.1 to 10 times the value of the coefficient of thermal expansion of the plate glass G, the coefficient of thermal expansion between the mold 1 and the sheet glass G is Due to the difference between the two values, when both expand due to heating, the occurrence of a situation in which a deviation occurs between the curved surfaces 11a, 12a and the glass sheet G due to the difference in the degree of expansion is preferably avoided. be able to. Therefore, it is possible to prevent the surface of the plate glass G from being damaged due to the shift at the portion where both the curved surfaces 11a and 12a and the plate glass G are in contact with each other.

  From the above, according to this glass sheet forming method, it is possible to prevent defects and scratches on the surface of the curved glass sheet after forming as much as possible. In addition to this, according to the method for forming a glass sheet, the following actions and effects can be obtained.

  That is, in this method, it is sufficient that the glass sheet G can be heated to the minimum temperature necessary for molding, so that the electric power consumed with the heating is reduced. Moreover, in this method, as described above, it is possible to suppress the occurrence of defects due to the softening of the glass sheet G as much as possible, and suitably prevent defects and scratches from remaining on the surface of the curved glass sheet after molding. Is possible. For this reason, from the viewpoint of preventing the surface of the plate glass G from being damaged, it is difficult to be restricted by the processing accuracy of the surfaces of the curved surfaces 11 a and 12 a of the mold 1 and the material selection of the mold 1. As a result, the mold 1 can be produced at a low cost. From these things, the manufacturing cost of curved plate glass can be reduced.

  Further, in the preheating step, since the mold 1 (the lower mold 11 and the upper mold 12) that sandwich and support the plate glass G is preheated, the time for heating the plate glass G to the molding temperature is shortened. It is also possible. As a result, the production efficiency of the curved plate glass can be improved. Further, when the heating step is performed in the manner as in this embodiment, the length of the heating furnace can be shortened.

  In this method, the glass sheet G at room temperature can be placed on the mold 1 (the lower mold 11 and the upper mold 12) in the clamping step. In this case, the glass sheet G at a low temperature is placed on the mold 1 as compared with the case where the softened glass sheet is placed. Thereby, the equipment for mounting the plate glass G is not easily damaged, and it is possible to extend the life of these equipment. Further, since the plate glass G is at room temperature, the plate glass G can be placed on the mold 1 manually by a person without using equipment or the like.

  Furthermore, when the dimensional difference between the thickness T of the curved forming space S and the thickness of the plate glass G is 0.2 mm to 1.0 mm, both curved surfaces 11a and 12a of the concave curved surface 11a and the convex curved surface 12a are used. However, the plate glass G can be sandwiched and supported in a stable state. Therefore, in the case of mass production of curved plate glass, it is also possible to suppress the occurrence of a situation in which a finish variation occurs between a plurality of curved plate glasses.

  In addition, since the curved plate glass shape | molded with this shaping | molding method of plate glass is hard to include a defect and a damage | wound on the surface, it can be made high quality. Moreover, when the plate glass G has a preferable composition as described above, a curved plate glass having high strength can be produced. And when manufacturing the touch panel provided with this curved plate glass and a touch sensor, since the high quality curved plate glass is used, favorable quality can be obtained also about the said touch panel.

  Hereinafter, the shaping | molding method of the plate glass which concerns on other embodiment of this invention is demonstrated. In addition, in description of the forming method of the plate glass which concerns on each subsequent embodiment, about each element which has the same function or shape as the element already demonstrated with the shaping | molding method of the plate glass which concerns on 1st embodiment mentioned above, each embodiment The same reference numerals are attached to the drawings for explaining the above, and the duplicated explanation is omitted. In each of the following embodiments, only differences from the first embodiment will be described.

  FIG. 3 is a diagram showing a method for forming a glass sheet according to the second embodiment of the present invention. As shown in the figure, the difference between the plate glass forming method according to the second embodiment and the plate glass forming method according to the first embodiment described above is that in the clamping step, the concave curved surface 11a and the plate glass Heat-resistant cloths 21 and 22 as sheet-like heat-resistant members are interposed between the lower surface of G and between the convex curved surface 12a and the upper surface of the sheet glass G, respectively.

  In the present embodiment, each of the heat resistant cloths 21 and 22 is made by knitting glass fibers. Here, as the heat-resistant cloths 21 and 22, in addition to knitted glass fibers, alumina fibers, metal fibers, knitted carbon fibers, glass fibers, alumina fibers, carbon fibers formed into a sheet shape, etc. Can be used. Each of the heat-resistant cloths 21 and 22 covers the entire lower surface and upper surface of the elastically deformed sheet glass G. As a result, the plate glass G is sandwiched in the plate thickness direction between the two locations (point A and point B) of the concave curved surface 11a and one location (point C) of the convex curved surface 12a via the heat resistant cloths 21 and 22. It is supported.

  In addition, the dimensional difference between the thickness T of the curved forming space S and the total thickness of the three layers made of the sheet glass G and the two heat resistant cloths 21 and 22 is 1.0 mm or less regardless of the total thickness of the three layers. Is preferable, more preferably 0.5 mm or less, and most preferably 0.2 mm.

  Also by the plate glass forming method according to the second embodiment, it is possible to obtain the same actions and effects as the plate glass forming method according to the first embodiment described above.

  Furthermore, in the glass sheet forming method according to the second embodiment, the surface of the glass sheet G and the curved surfaces 11a and 12a are prevented from coming into direct contact with each other due to the heat-resistant cloths 21 and 22 being interposed. Is more safely protected from defects and scratches. Therefore, it is possible to more suitably prevent defects and scratches from remaining on the surface of the curved plate glass after molding.

  FIG. 4 is a diagram showing a method for forming sheet glass according to the third embodiment of the present invention. As shown in the figure, the plate glass forming method according to the third embodiment is different from the plate glass forming method according to the first embodiment described above in that the mold 1 ( In the lower 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 (not curved with a constant curvature).

  Both the curved surfaces 11a and 12a have a minimum curvature in the central portion in the lateral direction, and gradually increase in curvature as they move from the central portion to the end side. That is, the radii of curvature R1 and R2 of the curved surfaces 11a and 12a are maximized at the center and minimized at both ends. For this reason, the center of curvature O 'approaches the curve forming space S as shown in FIG.

  Further, the radius of curvature R1 at points A and B of the concave curved surface 11a is such that the radius of curvature of the upper surface facing the lower surface of the glass sheet G supported at the points A and B is the radius of curvature at the point C of the convex curved surface 12a. It is adjusted to be equal to R2 (the maximum value of R2). Here, the size of the radius of curvature R1 of the concave curved surface 11a at the points A and B and the radius of curvature R2 of the convex curved surface 12a at the point C are the dimensions of the upper and lower surfaces of the sheet glass G, the thickness dimension of the sheet glass G, etc. It depends on various conditions. Accordingly, it is preferable to determine appropriate sizes for the radius of curvature R1 at the points A and B and the radius of curvature R2 at the point C in advance through tests, simulations, and the like.

Also by the glass sheet forming method according to the third embodiment, it is possible to obtain the same actions and effects as those of the glass sheet forming method according to the first embodiment described above. Further, the curved plate glass formed by this plate glass forming method is curved only along a single direction, and becomes a curved plate glass curved with a substantially constant curvature radius (substantially constant curvature). Note that “curved plate glass curved with a substantially constant curvature radius” means that GR _min ≧ (GR _max × _GRmax × (GR _max ××) when the maximum value of the curvature radius of the curved plate glass is GR _max and the minimum value of the curvature radius is GR _min. 0.9)).

  FIG. 5 is a diagram showing a method for forming a glass sheet according to the fourth embodiment of the present invention. As shown in the figure, the glass sheet forming method according to the fourth embodiment is different from the glass sheet forming method according to the first embodiment described above, through the mold 1 through the mold 1. Plate glass that is supported by the point where the three refrigerant passages 3 are formed and the points A and B on the concave curved surface 11a of the mold 1 and the C point on the convex curved surface 12a when the heating step is performed. Each part of G is cooled by the refrigerant flowing in the passage 3. Further, in the first embodiment described above, the heating step is performed by passing the inside of the heating furnace while the mold 1 is conveyed by the conveyor. However, in the present embodiment, the mold 1 is simply heated. The heating process is carried out in a state of being placed in the furnace.

  Each of the three passages 3 is formed inside a pipe 4 that penetrates the mold 1 and whose both ends extend outside the heating furnace. For each of the three pipes 4 forming each passage 3, a portion penetrating the mold 1 extends along a direction perpendicular to the paper surface in FIG. 5 and is also point A or point B on the concave curved surface 11a. Or, it passes through the vicinity of point C on the convex curved surface 12a. Each pipe 4 is connected to a refrigerant supply device (for example, a pump or the like) installed outside the heating furnace, and the refrigerant supplied from the device flows through the passage 3 when the heating step is performed. Has been.

  Here, air, water vapor, water, liquefied nitrogen, or the like can be used as the refrigerant. Further, as the material of the pipe 4, it is possible to use a metal such as stainless steel or a ceramic such as alumina, but it is preferable to use a metal having high thermal conductivity from the viewpoint of cooling efficiency. Further, the distance from each of the above points A, B, and C to the path 3 closest to each of these points is preferably shortened within a range where the mechanical strength of the mold 1 is allowed. 3 mm to 15 mm.

  Also by the glass sheet forming method according to the third embodiment, it is possible to obtain the same actions and effects as those of the glass sheet forming method according to the first embodiment described above. Moreover, according to this glass sheet forming method, since each part of the glass sheet G supported by the points A, B, and C is cooled by the refrigerant, it is possible to suppress softening of these parts by heat. It is easy to hold in a hard and scratch-resistant state. As a result, it is possible to more suitably prevent defects and scratches from remaining on the surface of the curved plate glass after molding.

  In the plate glass forming method according to the third and fourth embodiments described above, in the same manner as the plate glass forming method according to the second embodiment described above, in the clamping step, the lower surface of the plate glass G and the concave curved surface 11a. It is good also as an aspect which interposes a heat-resistant cloth between the upper surface and between the upper surface of the plate glass G, and the convex curved surface 12a.

  Here, the plate glass molding method and mold according to the present invention are not limited to the modes and configurations described in the above embodiments. For example, the molding die used in each of the above embodiments has a configuration in which a downwardly curved curve forming space is formed, but may have a configuration in which an upwardly convex curve forming space is formed. 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 this thickness is continuous. It may be configured to change.

  Moreover, between said 1st, 2nd, and 4th embodiment, and 3rd embodiment, the curvature radius of a concave curved surface and a convex curved surface is made different mutually between embodiment, and a curvature radius. However, it has become a mode in which curved plate glasses different from each other are formed. However, the curvature radius of the curved plate glass to be formed can be adjusted by a mode other than adjusting the curvature radius of the concave curved surface and the convex curved surface. That is, by adjusting at least one of the curvature radius of the concave curved surface, the curvature radius of the convex curved surface, and the separation distance of both curved surfaces, the curvature radius of the curved plate glass to be formed can be adjusted. Is possible. For example, when the distance between the curved surfaces is adjusted, the distance can be easily adjusted by interposing a spacer between the lower mold and the upper mold of the mold. Thereby, it is possible to adjust the curvature radius of the curved plate glass to be formed.

  Further, in the fourth embodiment, the passage for flowing the refrigerant is formed by the pipe penetrating the mold, but this is not restrictive. For example, it is good also as an aspect which forms the through-hole which penetrates the said shaping | molding die in a shaping | molding die, and flows a refrigerant | coolant in this through-hole. That is, the passage may be formed by a through hole. Further, when the passage is formed by a pipe that penetrates the mold, the direction in which the pipe penetrates the mold may be an arbitrary direction, and the number of pipes may be an arbitrary number.

  Furthermore, in each said embodiment, although curved plate glass is shape | molded by using a shaping | molding die, it is not this limitation. For example, using three fire-resistant rods, arranging two of them in parallel, supporting two spaced apart locations on one side of the sheet glass with line contact, and parallel to the two The other one arranged side by side supports one place on the other side located between the two places. And plate glass is pinched | interposed in the plate | board thickness direction in these three places, and plate glass is elastically deformed in the curved state. The curved plate glass can be formed by heating the elastically deformed plate glass.

DESCRIPTION OF SYMBOLS 1 Forming die 11 Lower mold | type 11a Concave curved surface R1 Curvature radius of concave curved surface 12 Upper mold | type 12a Convex curved surface R2 Curvature radius of convex curved surface 21,22 Heat-resistant cloth 3 Passage 4 Pipe G Plate glass A, B Concave curved surface and plate glass Location of contact with (heat resistant cloth) C Location of contact between convex curved surface and plate glass (heat resistant cloth) S Curve forming space T Thickness of curved forming space O Center of curvature O 'Center of curvature

Claims (12)

In a method of forming a flat plate glass into a curved plate glass having a curved shape,
The plate glass is supported by sandwiching the plate glass in the plate thickness direction at two locations spaced apart from each other on one side of the plate glass and at one location on the other side located between the two locations. A clamping step for elastically deforming into a curved state;
A heating step of forming the plate glass into the curved plate glass by heating the plate glass that has been elastically deformed. Using a mold having a concave curved surface and a convex curved surface facing the concave curved surface, and a curved molding space having a thickness larger than the thickness of the plate glass is formed between the curved surfaces. ,
2. The method for forming a glass sheet according to claim 1, wherein in the clamping step, the glass sheet is sandwiched and supported at two locations on the concave curved surface and at one location on the convex curved surface.   The method for forming a sheet glass according to claim 1 or 2, wherein, in the sandwiching step, the sheet glass is maintained at a temperature at which the sheet glass is not softened and deformed by heat.   The method for forming a glass sheet according to claim 2 or 3, wherein the concave curved surface and the convex curved surface are curved along the same single direction.   The method for forming a sheet glass according to any one of claims 2 to 4, wherein a thickness of the curved forming space is set to a constant thickness of 0.2 mm to 1.0 mm with respect to the sheet glass. In the heating step, the plate glass is formed into the curved plate glass in a temperature range in which the viscosity of the plate glass is 10 ⁸ dPa · s to 10 ¹⁵ dPa · s. The shaping | molding method of the plate glass of description.   In the said heating process, the said plate glass is shape | molded in the said curved plate glass in the temperature range of +/- 50 degreeC on the basis of the annealing point of this plate glass, The plate glass in any one of Claims 1-6 characterized by the above-mentioned. Molding method.   The plate glass forming method according to any one of claims 2 to 7, wherein a preheating step of preheating the mold is performed before the sandwiching step.   Adjusting the radius of curvature of the curved plate glass 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 curved surfaces. The shaping | molding method of the plate glass in any one of Claims 2-8 to do.   The value of the thermal expansion coefficient of the mold is in the range of 0.1 to 10 times the value of the thermal expansion coefficient of the plate glass. Molding method.   The sheet-like heat-resistant member is interposed between the concave curved surface and one surface of the plate glass and between the convex curved surface and the other surface of the plate glass in the clamping step. 10. The method for forming a plate glass according to any one of 10 to 10.   In the heating step, two portions of the concave curved surface in the molding die and each portion of the plate glass supported by one location of the convex curved surface are cooled by a refrigerant flowing in a passage passing through the molding die. The method for forming a glass sheet according to any one of claims 2 to 11, wherein:

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