阅读说明：本技术 挡风玻璃 (Windscreen ) 是由 神吉哲 于 2018-12-26 设计创作，主要内容包括：本发明所涉及的挡风玻璃具有：第一玻璃板,其具有第一面和第二面；第二玻璃板,其具有第一面和第二面,并且配置为该第一面与上述第一玻璃板的第二面相对；和中间膜,其夹持于上述第一玻璃板与第二玻璃板之间,上述第一玻璃板具有第一端部和与该第一端部相对的第二端部,并且形成为从上述第一端部向第二端部厚度变薄,在上述第一玻璃板中,上述第一端部侧的表面压缩应力比上述第二端部侧的表面压缩应力高。(The windshield according to the present invention includes: a first glass plate having a first side and a second side; a second glass plate having a first surface and a second surface, the first surface being disposed opposite to the second surface of the first glass plate; and an intermediate film sandwiched between the first glass plate and a second glass plate, wherein the first glass plate has a first end portion and a second end portion opposite to the first end portion, and is formed so as to be thinner in thickness from the first end portion toward the second end portion, and a surface compressive stress on the first end portion side is higher than a surface compressive stress on the second end portion side in the first glass plate.)

1. A windshield, comprising:

a first glass plate having a first side and a second side;

a second glass plate having a first face and a second face, and disposed such that the first face is opposite to the second face of the first glass plate; and

an intermediate film sandwiched between the first glass plate and the second glass plate,

the first glass plate has a first end portion and a second end portion opposite to the first end portion, and is formed to be thinner in thickness from the first end portion toward the second end portion,

in the first glass sheet, a surface compressive stress on the second end portion side is higher than a surface compressive stress on the first end portion side.

2. The windshield according to claim 1, wherein:

the second glass plate is formed of a flat plate having a substantially constant thickness.

3. The windshield according to claim 1 or 2, wherein:

the first and second surfaces of the first and second glass plates have different tin oxide concentrations,

the surface of the first glass plate on which the tin oxide concentration is low constitutes the second surface,

the surface of the second glass plate having a low concentration of tin oxide constitutes the first surface.

4. The windshield according to any one of claims 1-3, wherein:

at least one of a shielding layer and an antenna is laminated on the second side of the second glass plate.

5. The windshield according to any one of claims 1-4, wherein:

a stripe is formed on the first glass plate,

the second glass plate is formed with stripes orthogonal to the stripes of the first glass plate.

6. The windshield according to claim 1 or 2, wherein:

the first and second surfaces of the first and second glass plates have different tin oxide concentrations,

the surface of the first glass plate on which the tin oxide concentration is low constitutes the second surface,

the surface of the second glass plate having a high concentration of tin oxide constitutes the first surface.

7. The windshield according to claim 1, wherein:

the second glass sheet has first and second ends corresponding to the first and second ends of the first glass sheet,

the second glass sheet is formed to be thinner in thickness from the first end portion toward the second end portion.

8. The windshield according to any one of claims 1-7, wherein:

the first glass plate was not air-cooled and strengthened.

9. A method of manufacturing a windshield, comprising:

a step of forming a first glass plate in a curved shape having a first end portion and a second end portion opposite to the first end portion and formed to be thinner in thickness from the first end portion toward the second end portion;

a step of forming a second glass plate in a curved shape; and

a step of disposing an interlayer between the second surface of the first glass plate and the first surface of the second glass plate and applying pressure to integrate them,

in the molding of the first glass plate, the second end portion side is heated to a higher temperature than the first end portion side, and then molded into a curved shape.

10. A method of manufacturing a windshield, comprising:

a step of forming a first glass plate in a curved shape having a first end portion and a second end portion opposite to the first end portion and formed to be thinner in thickness from the first end portion toward the second end portion;

a step of forming a second glass plate in a curved shape; and

a step of disposing an interlayer between the second surface of the first glass plate and the first surface of the second glass plate and applying pressure to integrate them,

in the molding of the first glass plate, the second end portion side is air-cooled and strengthened.

Technical Field

The present invention relates to a windshield and a method of manufacturing the same.

Background

To prevent double images, windshields used in head-up display devices are generally formed in a wedge shape. In order to form the windshield into a wedge shape, there are various methods, and for example, patent document 1 discloses a windshield in which an intermediate film and an inner glass plate have a constant thickness and an outer glass plate is formed into a wedge shape.

Disclosure of Invention

Technical problem to be solved by the invention

However, there is still room for improvement in the wedge-shaped glass plate as described above, and improvement in strength is desired. The present invention has been made to solve the above problems, and an object of the present invention is to provide a windshield glass capable of improving the strength of a wedge-shaped glass plate, and a method for manufacturing the windshield glass.

Technical solution for solving technical problem

An windshield having:

a first glass plate having a first side and a second side;

a second glass plate having a first surface and a second surface, the first surface being disposed opposite to the second surface of the first glass plate; and

an intermediate film sandwiched between the first glass plate and the second glass plate,

the first glass plate has a first end portion and a second end portion opposite to the first end portion, and is formed to be thinner from the first end portion toward the second end portion,

in the first glass plate, a surface compressive stress on the second end portion side is higher than a surface compressive stress on the first end portion side.

The windshield according to claim 1, wherein the second glass sheet is formed of a flat sheet having a substantially constant thickness.

The windshield according to item 1 or 2, wherein the first surface and the second surface of the first glass sheet and the second glass sheet have different tin oxide concentrations,

the surface of the first glass plate on which the tin oxide concentration is low constitutes the second surface,

the surface of the second glass plate having a low concentration of the tin oxide constitutes the first surface.

The windshield according to any of claims 1-3, wherein at least one of a shielding layer and an antenna is laminated on the second face of the second glass sheet.

The windshield according to any one of claims 1-4, wherein a stripe is formed on the first glass sheet,

the second glass plate is formed with stripes orthogonal to the stripes of the first glass plate.

The windshield according to item 1 or 2, wherein the first surface and the second surface of the first glass sheet and the second glass sheet have different tin oxide concentrations,

the surface of the first glass plate on which the tin oxide concentration is low constitutes the second surface,

the surface of the second glass plate having a high concentration of tin oxide constitutes the first surface.

The windshield of claim 1, wherein the second glass sheet has first and second ends corresponding to the first and second ends of the first glass sheet,

the second glass plate is formed to have a thickness that decreases from the first end portion toward the second end portion.

The windshield according to any of claims 1-7, wherein the first glass sheet is not air-cooled and strengthened.

The method of manufacturing a windshield according to item 9, comprising:

a step of forming a first glass plate in a curved shape having a first end portion and a second end portion opposite to the first end portion, and formed to be thinner in thickness from the first end portion toward the second end portion;

a step of forming a second glass plate in a curved shape; and

a step of disposing an interlayer between the second surface of the first glass plate and the first surface of the second glass plate and applying pressure to integrate them,

in the molding of the first glass plate, the second end portion side is heated to a higher temperature than the first end portion side, and then molded into a curved shape.

A method of manufacturing a windshield, comprising:

a step of forming a first glass plate in a curved shape having a first end portion and a second end portion opposite to the first end portion, and formed to be thinner in thickness from the first end portion toward the second end portion;

a step of forming a second glass plate in a curved shape; and

a step of disposing an interlayer between the second surface of the first glass plate and the first surface of the second glass plate and applying pressure to integrate them,

in the molding of the first glass plate, the second end portion side is air-cooled and strengthened.

Effects of the invention

The invention can improve the strength of the wedge-shaped glass plate.

Drawings

Fig. 1 is a front view showing one embodiment of a windshield according to the present invention.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

FIG. 3 is a diagram illustrating an example of a method for manufacturing a float glass sheet.

Fig. 4 is a sectional view illustrating a method of cutting a glass plate.

FIG. 5 is a cross-sectional view of a float glass sheet.

FIG. 6 is a cross-sectional view of the windshield of FIG. 1.

Fig. 7 is a front view illustrating a stripe of the windshield of fig. 1.

FIG. 8 is another example of a cross-sectional view of the windshield of FIG. 1.

FIG. 9 is a schematic view of a glass plate molding apparatus.

FIG. 10 is a schematic plan view of a heating furnace for glass sheets.

Fig. 11 is a schematic view of the head-up display device.

Detailed Description

< 1. summary of windshield glass >

An embodiment of a windshield of an automobile according to the present invention will be described below with reference to the drawings. The windshield according to the present embodiment is used for displaying information by projecting irradiated light with a head-up display device.

Fig. 1 is a front view of a windshield according to the present embodiment, and fig. 2 is a sectional view taken along line a-a of fig. 1. As shown in fig. 1 and 2, the windshield according to the present embodiment includes an outer glass plate 1, an inner glass plate 2, and an interlayer 3 disposed between these glass plates 1 and 2. A shielding layer 4 is laminated on the windshield. Hereinafter, each member will be explained.

< 2. outer and inner glass plates >

First, the outer glass plate 1 and the inner glass plate 2 will be described. The outer glass plate 1 and the inner glass plate 2 may be formed of a known glass plate, or may be formed of heat absorbing glass, general transparent glass, green glass, or UV green glass. However, these glass sheets 1, 2 are required to achieve visible light transmittance in accordance with the national safety standards for use in automobiles. For example, it is possible to adjust so that the necessary solar absorptance is ensured by the outer glass plate 1 and so that the visible light transmittance of the inner glass plate 2 satisfies the safety standard. Hereinafter, examples of transparent glass, heat absorbing glass, and soda-lime glass will be described.

(transparent glass)

SiO₂: 70 to 73 mass%

Al₂O₃: 0.6 to 2.4% by mass

CaO: 7 to 12% by mass

MgO: 1.0 to 4.5% by mass

R₂O: 13 to 15 mass% (R is an alkali metal)

Conversion to Fe₂O₃Total iron oxide (T-Fe)₂O₃): 0.08 to 0.14% by mass

(Heat absorbing glass)

The composition of the heat absorbing glass may be, for example, as follows: based on the composition of the transparent glass, the conversion is Fe₂O₃Total iron oxide (T-Fe)₂O₃) In an amount of 0.4 to 1.3 mass%, to thereby obtain CeO₂The ratio of (A) to (B) is 0 to 2 mass%, and TiO is added₂The ratio of (A) to (B) is 0 to 0.5 mass%, and the glass contains a skeleton component (mainly SiO)₂、Al₂O₃) Reduction of T-Fe only₂O₃、CeO₂And TiO₂The amount of increase of (c).

(soda-lime glass)

SiO₂: 65 to 80 mass%

Al₂O₃: 0 to 5% by mass

CaO: 5 to 15% by mass

MgO: 2 mass% or more

NaO: 10 to 18% by mass

K₂O: 0 to 5% by mass

MgO + CaO: 5 to 15% by mass

Na₂O+K₂O: 10 to 20% by mass

SO₃: 0.05 to 0.3 mass%

B₂O₃: 0 to 5% by mass

Conversion to Fe₂O₃Total iron oxide (T-Fe)₂O₃): 0.02 to 0.03 mass%

The outer glass plate 1 is formed in a trapezoidal shape having an upper side (first end) 11, a lower side (second end) 12, a right side 13 and a left side 14. The outer glass plate has a first surface 101 facing the vehicle exterior side and a second surface 102 facing the vehicle interior side, and has an end surface connecting these first and second surfaces. The outer glass plate 1 is formed in a wedge shape such that the thickness thereof decreases from the upper side 11 to the lower side 12. The inner glass plate 2 is also formed in a trapezoidal shape, and has an upper side 21, a lower side 22, a right side 23, and a left side 24. The inner glass plate also has a first surface 201 facing the vehicle exterior side and a second surface 202 facing the vehicle interior side, and has an end surface connecting the first surface 201 and the second surface 202. The inner glass plate 2 is formed of a flat plate having a constant thickness, unlike the outer glass plate 1.

The interlayer 3 is disposed between the second surface 102 of the outer glass plate 1 and the first surface 201 of the inner glass plate 2.

The thickness of the windshield according to the present embodiment is not particularly limited, and from the viewpoint of weight reduction, the total thickness of the outer glass plate 1 and the inner glass plate 2 is preferably 2.4 to 5.0mm, more preferably 2.6 to 4.6mm, and particularly preferably 2.7 to 3.2 mm. In this way, in order to reduce the weight, the total thickness of the outer glass plate 1 and the inner glass plate 2 needs to be reduced, and therefore the thickness of each of the glass plates 1 and 2 is not particularly limited, and the thickness of the outer glass plate 1 and the thickness of the inner glass plate 2 can be determined as follows, for example. The thickness of each glass plate 1, 2 can be measured by a micrometer.

The outer glass plate 1 is required to have durability and impact resistance mainly against external obstacles, and to have impact resistance against flying objects such as pebbles. On the other hand, the larger the thickness, the more increased the weight, which is not preferable. From this viewpoint, the thickness of the outer glass plate 1 is preferably 1.8 to 2.3mm, and more preferably 1.9 to 2.1 mm. Which thickness is used may be determined according to the use of the glass. However, since the upper side 11 is thicker than the lower side 12, for example, the thickness of the upper side 11 may be 2.5 to 5.0mm, the thickness of the lower side 12 may be 2.6 to 6.7mm, and the difference between the thicknesses of the upper side 11 and the lower side 12 may be 0.1 to 1.7 mm.

The thickness of the inner glass plate 2 may be equal to that of the outer glass plate 1, and for example, the thickness may be smaller than that of the outer glass plate 1 for the purpose of weight reduction of the windshield. Specifically, the glass strength is preferably 0.6 to 2.3mm, more preferably 0.8 to 2.0mm, and particularly preferably 1.0 to 1.4 mm. More preferably 0.8 to 1.3 mm. The thickness of the inner glass plate 2 may be determined according to the intended use of the glass.

The outer glass plate 1 and the inner glass plate 2 according to the present embodiment have curved shapes. When the windshield is curved, the sound insulation performance is reduced when the amount of curvature is increased. The bending amount is an amount indicating the bending of the windshield, and for example, when a straight line connecting the center of the upper side 11 and the center of the lower side 12 of the windshield is set, the maximum value of the distance between the straight line and the windshield is defined as the bending amount.

Here, an example of a method for measuring the thickness of the windshield 1 will be described. First, the measurement positions are 2 positions above and below a center line extending vertically from the center of the windshield in the lateral direction. The measuring apparatus is not particularly limited, and for example, a thickness meter such as SM-112 manufactured by Techlock, Inc. can be used. In the measurement, the curved surface of the windshield is placed on a flat surface, and the end of the windshield is sandwiched by the thickness gauge.

< 3. method for manufacturing outer glass plate and inner glass plate

Next, an example of a method for manufacturing the outer glass plate 1 and the inner glass plate 2 will be described with reference to fig. 3. As an example, the outer glass plate 1 and the inner glass plate 2 may be float glass plates manufactured by a float process.

FIG. 3 is a view showing a method for producing a float glass sheet. In fig. 3, the vertical direction of the drawing is the flow direction of the molten glass 55, and the horizontal direction is the width direction of the molten glass 55. In fig. 4, the change in the thickness of the molten glass 55 is exaggeratedly shown.

In the float process, molten glass 55 is continuously supplied onto molten metal 54 such as molten tin, and the supplied molten glass 55 is made to flow over the molten metal 54, thereby forming the molten glass into a band-like plate shape. The glass thus formed is referred to as a glass ribbon 55.

In order to suppress the shrinkage of the glass ribbon 55 in the width direction, both ends of the glass ribbon 55 in the width direction are pressed by a pair of rollers 56. The pair of rollers 56 is provided in plurality at intervals in the flow direction of the glass ribbon 55. By rotating these plural pairs of rollers 16, the glass ribbon 55 moves downstream.

The glass ribbon 55 is cooled down toward the downstream side, and after cooling and solidification, is lifted up from the molten metal 54. Then, the mixture was cooled slowly and cut. This operation can yield a float glass sheet. In the float glass sheet, the surface in contact with the molten metal 54 is referred to as a bottom surface, and the surface opposite thereto is referred to as a top surface. The bottom and top surfaces may not be ground. Further, since the bottom surface is in contact with the molten metal 54, when the molten metal 54 is tin, the concentration of tin oxide contained in the bottom surface is greater than the concentration of tin oxide contained in the top surface.

In fig. 3, the glass ribbon 55 is stretched in the width direction by a pair of rollers 56, so that the thickness of the glass ribbon 55 increases from both ends in the width direction toward the center. The glass ribbon 55 thus formed is cured and then cut to obtain the outer glass plate 1. At this time, as shown in fig. 4, there are 2 kinds of cutting methods of the outer glass plate. First, as shown on the right side of fig. 4, the glass ribbon 55 is cut so that the cut surfaces K1 and K2 extend in the vertical direction. The cut surfaces K1 and K2 extend in parallel, and the cut surfaces K1 and K2 of the outer glass plate 1A thus obtained are orthogonal to the bottom surface. In another method, the glass ribbon 55 is cut so as to form cut surfaces K3 and K4 perpendicular to the top surface, as shown on the left side of fig. 4. The cut surfaces K3 and K4 extend in parallel, and the cut surfaces K3 and K4 of the outer glass plate 1B obtained in this way are orthogonal to the top surface. Which cutting method is employed depends on the performance required for the windshield obtained as described below. In any of the methods, the outer glass sheet 1 having the upper side 11 with a large thickness and the lower side 12 with a small thickness can be cut.

On the other hand, the inner glass plate 2 is also formed by the float process in the same manner as the outer glass plate 1, and the thickness of the inner glass plate 2 is formed substantially constant by a known method.

In addition, since the glass ribbon 55 flows over the molten metal 54, a plurality of streaks extending in the flow direction are formed on the surface thereof. The streaks are also formed on the surface of the float glass sheet after cooling. As shown in fig. 5, wavy irregularities are formed on the surface of the inner glass plate 2 in the direction of the stripes by the stripes. Wherein fig. 5 is the same cross section as fig. 3, showing a cross section orthogonal to the flow direction of the glass sheet. The same unevenness is formed on the outer glass plate 1. However, in each of the glass plates 1 and 2, the bottom surface contacting the molten metal 54 has smaller irregularities than the top surface. Here, the small unevenness means that the difference between the deepest portion and the uppermost portion of the unevenness is small. In addition to the above-described streaks, ripples extending in a direction perpendicular to the streaks are formed on the surface of the glass sheet formed by the float process. The corrugations have a pitch larger than that of the stripes and a size smaller than that of the irregularities of the stripes.

As shown in fig. 6, the windshield according to the present embodiment has both the second surface 102 of the outer glass plate 1 and the first surface 201 of the inner glass plate 2 as the top surfaces. Accordingly, the irregularities of the first surface 101 of the outer glass plate 1 and the second surface 202 of the inner glass plate 2, i.e., the surface facing the outside of the windshield, are small. Accordingly, in the windshield, since the surface facing the outside is a surface having small irregularities, the see-through distortion can be reduced.

In the present embodiment, as shown in fig. 7, the stripes of the outer glass plate 1 are orthogonal to the stripes of the inner glass plate 2. That is, the stripes 150 of the outer glass plate 1 extend in parallel with the upper side 11 and the lower side 12 by the above-described method. On the other hand, since the thickness of the inner glass plate 2 is constant, the glass ribbon is cut so that the striae 250 extend from the upper side 21 to the lower side 22 in order to adjust the direction of the striae. In this way, the windshield is formed so that the stripes 150 of the outer glass plate 1 are orthogonal to the stripes 250 of the inner glass plate 2.

In addition, in the manufacture of the outer glass sheet 1, the thickness may be increased from both ends in the width direction toward the center portion or from one end in the width direction toward the other end, by adjusting the molding conditions. The thickness of the glass ribbon 55 can be adjusted by, for example, the peripheral speed of the roller 56, in addition to the tension of the roller 56.

< 4. intermediate Membrane >

The intermediate film 3 has a substantially constant thickness and is formed of at least one layer. As an example, as shown in the enlarged view of fig. 2, the core layer 31 may be composed of 3 layers sandwiched by outer layers 32 which are harder than the soft core layer 31. However, the present invention is not limited to this configuration, and a plurality of layers including the core layer 31 and at least 1 outer layer 32 disposed on the outer glass plate 1 side may be used. For example, the interlayer film 3 may be formed by 2 layers including the core layer 31 and 1 outer layer 32 disposed on the outer glass plate 1 side, or the interlayer film 3 may be formed by disposing 2 or more even-numbered outer layers 32 on both sides of the core layer 31, or the interlayer film 3 may be formed by disposing an odd-numbered outer layer 32 on one side and an even-numbered outer layer 32 on the other side with the core layer 31 interposed therebetween. In addition, when only 1 outer layer 32 is provided, it is provided on the outer glass plate 1 side as described above, in order to improve the breakage resistance against external force from the outside of the vehicle and the outside. In addition, when the number of the outer layers 32 is large, the sound insulation performance is also high.

The hardness of the core layer 31 is not particularly limited as long as it is softer than the outer layer 32. The material constituting each layer 31, 32 is not particularly limited, and for example, the outer layer 32 may be formed of polyvinyl butyral resin (PVB). The polyvinyl butyral resin is preferable because it is excellent in adhesion to each glass plate and penetration resistance. On the other hand, the core layer 31 may be made of, for example, an ethylene vinyl acetate resin (EVA) or a polyvinyl acetal resin softer than the polyvinyl butyral resin constituting the outer layer. By sandwiching the soft core layer, the sound insulation performance can be greatly improved while maintaining the same adhesiveness and penetration resistance as those of a single-layer resin interlayer film.

In general, the hardness of the polyvinyl acetal resin can be controlled by the polymerization degree of polyvinyl alcohol (a) as a starting material, (b) acetalization degree, (c) kind of the plasticizer, (d) addition ratio of the plasticizer, and the like. Therefore, by appropriately adjusting at least 1 selected from these conditions, it is possible to produce a hard polyvinyl butyral resin used for the outer layer 32 and a soft polyvinyl butyral resin used for the core layer 31, respectively, even with the same polyvinyl butyral resin. In addition, the hardness of the polyvinyl acetal resin can also be controlled by the kind of aldehyde used for the acetalization, co-acetalization of a plurality of aldehydes, or pure acetalization of a single aldehyde. Although not all together, a polyvinyl acetal resin obtained by using an aldehyde having a larger carbon number tends to be more flexible. Therefore, for example, when the outer layer 32 is made of a polyvinyl butyral resin, the core layer 31 may be made of a polyvinyl acetal resin obtained by acetalizing an aldehyde having 5 or more carbon atoms (for example, n-hexanal, 2-ethylbutyraldehyde, n-heptaldehyde, and n-octanal) with polyvinyl alcohol. When a predetermined young's modulus can be obtained, the young's modulus is not limited to the above-mentioned resin.

The total thickness of the interlayer film 3 is not particularly limited, but is preferably 0.3 to 6.0mm, more preferably 0.5 to 4.0mm, and particularly preferably 0.6 to 2.0 mm. The thickness of the core layer 31 is preferably 0.1 to 2.0mm, and more preferably 0.1 to 0.6 mm. On the other hand, the thickness of each outer layer 32 is preferably 0.1 to 2.0mm, more preferably 0.1 to 1.0 mm. Further, the total thickness of the intermediate film 3 may be constant, and the thickness of the core layer 31 may be adjusted.

The thicknesses of the core layer 31 and the outer layer 32 can be measured, for example, as follows. First, a cross section of the windshield glass is enlarged 175 times by a microscope (for example, VH-5500 manufactured by Keyence corporation). Then, the thicknesses of the core layer 31 and the outer layer 32 were determined by visual observation and measured. In this case, in order to eliminate variations caused by visual observation, the number of measurements was set to 5, and the average value was taken as the thicknesses of the core layer 31 and the outer layer 32.

The total thickness of the interlayer film 3 is not particularly limited, but is preferably 0.3 to 6.0mm, more preferably 0.5 to 4.0mm, and particularly preferably 0.6 to 2.0 mm. The thickness of the core layer 31 is preferably 0.1 to 2.0mm, and more preferably 0.1 to 0.6 mm. On the other hand, the thickness of each outer layer 32 is preferably larger than the thickness of the core layer 31, specifically, preferably 0.1 to 2.0mm, and more preferably 0.1 to 1.0 mm. Further, the total thickness of the intermediate film 3 may be constant, and the thickness of the core layer 31 may be adjusted.

The thicknesses of the core layer 31 and the outer layer 32 can be measured, for example, as follows. First, a cross section of the windshield glass is enlarged 175 times by a microscope (for example, VH-5500 manufactured by Keyence corporation). Then, the thicknesses of the core layer 31 and the outer layer 32 were determined by visual observation and measured. In this case, in order to eliminate variations caused by visual observation, the number of measurements was set to 5, and the average value was taken as the thicknesses of the core layer 31 and the outer layer 32. For example, a magnified photograph of the windshield is taken, in which the core and outer layers 32 are identified, and the thickness is measured.

The method for producing the intermediate film 3 is not particularly limited, and examples thereof include a method in which the resin component such as the polyvinyl acetal resin, the plasticizer, and other additives as necessary are blended and uniformly kneaded, and then the layers are collectively extruded; a method of laminating 2 or more kinds of resin films produced by this method by a pressing method, a laminating method, or the like. The resin film before lamination used in the method of lamination by a pressing method, a lamination method, or the like may have a single-layer structure or a multi-layer structure. The interlayer film 3 may be formed of 1 layer in addition to the above-described multilayer.

< 5. Shielding layer >

As shown in fig. 1, a shielding layer 2 made of a ceramic having a dark color such as black is laminated on the periphery of the windshield. The shielding layer 4 shields a view from the inside or outside of the vehicle, and is laminated along 4 edges of the windshield.

The shielding layer 4 may be formed in various forms such as only the inner surface of the outer glass plate 1, only the inner surface of the inner glass plate 2, or the inner surfaces of the outer glass plate 1 and the inner glass plate 2. The ceramic material may be made of ceramics or various materials, and may have the following composition, for example.

[ Table 1]

		First and second colored ceramic pastes
			Pigment 1	Mass%	20
Resin (cellulose resin)	Mass%	10
			Organic solvent (pine oil)	Mass%	10
Glass binder 2	Mass%	65
			Viscosity of the oil	dPs	150

1, main components: copper oxide, chromium oxide, iron oxide and manganese oxide

2, main components: bismuth borosilicate and zinc borosilicate

The ceramic may be formed by a screen printing method, or may be produced by transferring a transfer film for firing to a glass plate and firing the transferred film. When screen printing is used, for example, a polyester screen: 355 mesh, coating thickness: 20 μm, tension: 20Nm, blade hardness: 80 degrees, installation angle: 75 °, printing speed: 300mm/s, and dried at 150 ℃ for 10 minutes in a drying furnace to form a ceramic.

Further, the ceramics easily adheres to the bottom surface of the glass ribbon 55. This is because the concentration of tin oxide at the bottom surface is high. Therefore, when the shielding layer 4 is formed of ceramic, it is preferably formed on the bottom surface. Therefore, for example, when a windshield as shown in fig. 6 is formed, the shielding layer 4 may be formed on the second surface 202 of the inner glass plate 2. Alternatively, as shown in fig. 8, the shielding layer 4 may be laminated on the first surface 201 of the inner glass plate 2, with the first surface 201 being the bottom surface. However, fig. 8 illustrates an example in which the stripes of the two glass plates 1 and 2 are parallel to each other for convenience of explanation. The shielding layer 4 may be formed by laminating a shielding film made of a resin of a dark color, in addition to the laminated ceramic.

< 6. method for manufacturing windshield glass

Next, a method for manufacturing a windshield will be described. First, a production line of a glass sheet will be explained.

As shown in fig. 9, in this production line, a heating furnace 901 and a molding device 902 are arranged in this order from the upstream to the downstream. Further, a roller conveyor 903 is disposed from the heating furnace 901 to the molding device 902 and over the downstream side thereof, and the glass sheets 1 and 2 to be processed are conveyed by the roller conveyor 903. The glass plates 1 and 2 are formed into flat plates before being carried into the heating furnace 901, and the shielding layer 4 is stacked on the glass plates 1 and 2, and then carried into the heating furnace 901.

The heating furnace 901 may have various configurations, and may be an electric heating furnace, for example. The heating furnace 901 has a rectangular tube-shaped furnace body having open ends on the upstream side and the downstream side, and a roller conveyor 903 is disposed inside the furnace body from the upstream side to the downstream side. Heaters (not shown) are disposed on the upper surface, the lower surface, and the pair of side surfaces of the inner wall surface of the furnace main body, respectively, and the glass plate 10 passed through the heating furnace 901 is heated to a temperature at which the glass can be formed, for example, in the vicinity of the softening point of the glass.

The molding apparatus 902 is configured to press the glass plates 1 and 2 by the upper mold 921 and the lower mold 922 to mold the glass plates into a predetermined shape. The upper mold 921 has a curved surface shape protruding downward so as to cover the entire upper surfaces of the glass plates 1 and 2, and is configured to be movable up and down. The lower mold 922 is formed in a frame shape corresponding to the peripheral edge portions of the glass plates 1 and 2, and has a curved surface shape on the upper surface corresponding to the upper mold 921. With this configuration, the glass sheets 1 and 2 are press-molded between the upper mold 921 and the lower mold 922 to be formed into a final curved surface shape. Further, a roller conveyor 903 is disposed in the frame of the lower mold 922, and the roller conveyor 903 is vertically movable so as to pass through the frame of the lower mold 922. Although not shown, a slow cooling device (not shown) is disposed downstream of the molding device 902 to cool the molded glass sheet.

The roller conveyor 903 as described above is a well-known apparatus, and a plurality of rollers 931 are arranged at a predetermined interval to rotatably support both end portions. Various methods are used to drive each roller 931, and for example, a sprocket may be attached to an end of each roller 931 and a chain may be wound around the sprocket to drive each sprocket. Further, the conveyance speed of the glass sheet 10 can also be adjusted by adjusting the rotation speed of each roller 931. The lower mold 922 of the molding apparatus 902 may be in contact with the entire surfaces of the glass sheets 1 and 2. The form of the upper mold and the lower mold is not particularly limited as long as the molding apparatus 902 can mold the glass plate.

In order to mold the outer glass plate into a wedge shape, the heating furnace 901 may be heated as follows. That is, as shown in fig. 10, the outer glass plate 1 is moved in the heating furnace in a direction orthogonal to the extending direction of the upper side 11 and the lower side 12. The temperature of the lower side 12 of the outer glass plate 1 is made higher than that of the upper side 11. There are various methods for adjusting the temperature, and for example, a plurality of additional heaters may be provided along the traveling direction of the heating furnace, only the lower side of the glass sheet to be conveyed is heated by the additional heaters, and the heaters may be turned off (or the output may be reduced) and not heated when the upper side passes. However, other methods may be used as appropriate if the heating temperature on the lower side can be increased. After the heating, press molding and slow cooling were performed in the same manner as shown in fig. 9.

However, the inner glass plate having a constant thickness is not heated as described above, and is heated substantially uniformly over the entire inner glass plate.

In this way, the outer glass plate 1 and the inner glass plate 2 are formed, and then the interlayer 3 is sandwiched between the outer glass plate 1 and the inner glass plate 2. The interlayer 3 is formed in a shape slightly larger than the outer glass plate 1 and the inner glass plate 2. Thereby, the outer edge of the intermediate layer 3 is exposed from the outer glass pane 1 and the inner glass pane 2.

Subsequently, a laminate obtained by laminating the two glass plates 1 and 2 and the intermediate film 3 was placed in a rubber bag, and pre-bonded at about 70 to 110 ℃ while vacuum suction was performed. As the method of pre-bonding, the following method may be employed in addition to the method. For example, the laminate is heated at 45 to 65 ℃ in an oven. Then, the laminate is pressed by a roller at 0.45 to 0.55 MPa. Then, the laminate is heated again in an oven at 80 to 105 ℃ and then pressed again by a roller at 0.45 to 0.55 MPa. Thus, pre-bonding is completed.

Subsequently, main bonding is performed. The pre-bonded laminate is subjected to main bonding by an autoclave at, for example, 8 to 15 atmospheres at 100 to 150 ℃. Specifically, the main bonding may be performed under a condition of, for example, 14 atmospheres and 135 ℃. The intermediate film 3 is bonded to the glass plates 1 and 2 by the pre-bonding and the main bonding. Finally, the interlayer film 3 exposed from the outer glass plate 1 and the inner glass plate 2 is cut to complete the windshield. Other methods, such as bending by its own weight, may be used.

< 7 > head-up display device

Next, the head-up display device will be described. A head-up display device (referred to as a HUD device) projects information such as a vehicle speed on a windshield. However, it is known that, when using this HUD device, a double image is formed by light projected on the windshield. That is, the image recognized by being reflected on the inner surface of the windshield and the image recognized by being reflected on the outer surface of the windshield are recognized, and the images are doubled.

In order to prevent this, a wedge-shaped windshield is used as the outer glass panel 1 as in the present embodiment. That is, as shown in fig. 11, the windshield is formed such that the thickness thereof decreases downward at least in the display region where light is projected from the HUD device 500. Accordingly, the light reflected by the inner surface of the windshield (the second surface 202 of the inner glass plate 2) and incident into the vehicle interior and the light reflected by the outer surface of the windshield (the first surface 101 of the outer glass plate 1) and incident into the vehicle interior are substantially identical, and therefore, double images are eliminated. The wedge angle α of the windshield 1, that is, the angle formed by the first surface 101 and the second surface 101 of the outer glass plate 1 at this time may be, for example, 0.01 to 0.04 degrees (0.2 to 0.7mrad) depending on the installation angle of the windshield 1.

< 8. feature >

With the windshield according to the present embodiment, the following effects can be obtained.

(1) The inventors of the present invention have found that the following problems occur when a wedge-shaped glass plate is uniformly heated and then press-molded, as in the outer glass plate 1. That is, since the lower side of the outer glass sheet 1 is thin, when the outer glass sheet is carried out from the heating furnace 901 and cooled, the inside of the glass sheet 1 is easily cooled as in the case of the surface, and as a result, the temperature difference between the surface and the inside becomes small. On the other hand, since the thickness of the upper side 11 is large, when the glass sheet 1 is carried out from the heating furnace and cooled, the surface is more easily cooled than the inside, and therefore, the temperature difference between the surface and the inside becomes large.

When press molding is performed in a state where a temperature difference is generated as described above, the surface compressive stress on the lower side 12 side of the outer glass sheet 1 is considered to be smaller than that on the upper side 11 side. That is, the inventors of the present invention have found that the lower edge 12 side of the outer glass plate 1 is thin and the strength may be low because the surface compressive stress is low.

Therefore, in the present embodiment, as shown in fig. 10, the temperature of the lower side 12 side of the outer glass sheet 1 is raised in the heating furnace 901. This increases the heat capacity on the lower side 12 side, and when the glass sheet 1 is carried out from the heating furnace 901 and cooled, the surface of the glass sheet 1 is more easily cooled than the inside even if the thickness is small. As a result, the surface-internal temperature difference can be increased, and the surface compressive stress can be increased. Therefore, even if the thickness of the lower side 12 side of the outer glass plate 1 is thin, the strength can be improved because the surface compressive stress becomes high. That is, the lower side 12 side of the outer glass plate 1 can have a higher surface compressive stress without being subjected to a strengthening treatment such as air-cooling strengthening.

The surface compressive stress on the upper side 11 side may be, for example, 4 to 6MPa, and the surface compressive stress on the lower side 12 side may be, for example, 5 to 7 MPa. If the glass sheet strength is lower than the lower limit, the glass sheet strength may be lowered. On the other hand, in view of strength, there is a method of further strengthening by raising the temperature in the furnace, but when the surface compressive stress is too high, deformation may occur. In addition, there are also the following problems. That is, the outer glass plate 1 and the inner glass plate 2 do not necessarily have to have the same dimensional accuracy before sandwiching the interlayer film 3, and the interlayer film 3 is sandwiched in a state where tensile and compressive stresses are applied to either. In this case, when the surface compressive stress is too large, if a large value of the surface compressive stress is applied before lamination, the glass sheet is not suitably broken or the allowable value of breakage becomes small at the time of lamination. Therefore, the above-mentioned value is preferable as the upper limit value.

(2) In the above embodiment, the bottom surface with small irregularities generated by the stripes is used as the outer surface of the windshield. That is, since the irregularities of the 2 outer surfaces of the windshield are small, the perspective distortion can be reduced when the object outside the vehicle is viewed through the windshield from the inside of the vehicle.

(3) In the above embodiment, the two glass plates 1 and 2 are arranged so that the stripes 150 of the outer glass plate 1 are orthogonal to the stripes 250 of the inner glass plate 2. On the other hand, for example, when the stripes 150 and 250 of the two glass plates 1 and 2 extend in the same direction, the thickness of the entire windshield may vary greatly by the combination of the stripes on the vehicle outer side surface of the windshield and the stripes on the vehicle outer side surface of the windshield. Thereby, the perspective distortion may increase. Therefore, in the present embodiment, since the stripes 150 and 250 of the two glass plates 1 and 2 are orthogonal to each other, the unevenness is prevented from increasing, and the see-through distortion can be suppressed.

< 9. variation

While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications may be made without departing from the spirit and scope of the invention. Further, a plurality of modifications shown below can be combined as appropriate.

＜9－1＞

In the above embodiment, the heating furnace 901 may be other than those shown in fig. 9 and 10. That is, the temperature of the lower side 12 may be higher than that of the upper side 11. For example, instead of increasing the temperature on the lower side 12 side, the temperature distribution of the heating furnace may be set such that the temperature increases from the upper side 11 side to the lower side 12 side.

＜9－2＞

Further, the air-cooling strengthening may be performed only on the lower side 12 side of the outer glass plate 1. For example, in the heating furnace 901, after the entire outer glass sheet 1 is heated and pressed substantially uniformly, air may be blown only to the lower edge 12 side to lower the surface temperature. This can increase the temperature difference between the surface of the lower side 12 and the inside, and can increase the surface compressive stress.

＜9－3＞

As described above, the bottom surface has an advantage that the see-through deformation can be suppressed when the bottom surface is the outer surface of the windshield, but the bottom surface is advantageous when the shielding layer 4 of ceramic is laminated. Therefore, it is possible to examine which surface is opposed to each other according to the application. That is, in addition to the arrangement in which the top surfaces of the outer glass plate 1 and the inner glass plate 2 are opposed to each other as described above, for example, the bottom surfaces may be opposed to each other. Alternatively, the top surface may be disposed opposite to the bottom surface. Such a bottom surface is suitable for laminating an antenna element such as copper or silver, for example, by printing or the like, in addition to the shielding layer 4. In addition, silver has high color developability when it is provided on a bottom surface having a high concentration of tin oxide.

＜9－4＞

In the above embodiment, the inner glass plate 2 is a flat plate, but the inner glass plate 2 may be formed in a wedge shape similarly to the outer glass plate 1. This makes it possible to make the wedge angle of the windshield the sum of the wedge angles of the two glass plates 1 and 2, and thus the wedge angle of each glass plate 1 and 2 can be made small. Therefore, the glass plate is easily molded.

When the inner glass plate 2 is formed into a wedge shape, the lower side 12 side surface compressive stress can be increased by molding in the same manner as the outer glass plate 1.

＜9－5＞

In the above embodiment, the stripes of the outer glass plate 1 and the inner glass plate 2 are orthogonal to each other, but may be parallel.

＜9－6＞

The shape of the shielding layer 4 is not particularly limited, and various shapes are possible. For example, a shielding layer provided with a window may be formed so that light can be irradiated by a sensor or external imaging can be performed by a camera.

＜9－7＞

The method for forming the outer glass plate 1 and the inner glass plate 2 in the wedge shape is not particularly limited, and a method other than the above-described method may be used.

Description of the symbols

1 outer glass plate (first glass plate)

2 inner side glass plate (second glass plate)

3 an intermediate film.