JP2004210619A - Glass panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass panel which can certainly maintain the essential strength of a tempered sheet glass by avoiding strength lowering of the glass panel caused by warping to the thickness direction at a peripheral edge part of the tempered sheet glass which constitutes the glass panel. <P>SOLUTION: The glass panel consists of a pair of tempered glass sheets 1 and 2 placed to be faced each other via a space part V sealed to be airtight by directly joining the peripheral edge parts of the both tempered glass sheets 1 and 2 with a metal material 4. When a warping amount in the thickness direction of the both tempered glass sheets 1 and 2 for a unit length of 100mm in the direction along the peripheral edge parts is Xmm, and surface compressive stress of the both tempered glass sheets 1 and 2 is A kg/cm<SP>2</SP>and a sheet thickness is t mm, an inequality denoted as Xt≤(A+800)/650×(4/t)<SP>3</SP>×0.1 is satisfied. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a glass panel in which a pair of tempered glass sheets are arranged to face each other via a gap, and the peripheral portions of both tempered glass sheets are directly joined with a metal material to hermetically seal the gap.
[0002]
[Prior art]
Conventionally, focusing on the wettability of a metal material with respect to a sheet glass in this type of glass panel, the joining surface strength of the two sheet glasses is controlled by controlling the average surface roughness of the joining surface with the metal material to be equal to or less than a predetermined roughness. There is known a configuration in which the airtightness of the gap is maintained by securing the airtightness (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP 2002-167249 A
[Problems to be solved by the invention]
However, in the glass panel disclosed in the above publication, in order to secure the bonding strength between the both glass sheets, although attention is paid to the surface roughness of the bonding surface between the both glass sheets, special consideration is given to the warpage at the peripheral portions of the both glass sheets. Has not been paid.
[0005]
The present inventors have focused on the effect of the amount of warpage at the peripheral edges of both glass sheets constituting the glass panel, in particular, the amount of warpage at the peripheral edge of the tempered glass sheet strengthened by heating, on the overall strength of the glass panel. And repeated the experiment to obtain a new conclusion.
[0006]
The present invention is based on the novel conclusion, and its object is to avoid a decrease in the strength of the glass panel due to warpage in the thickness direction at the periphery of the tempered glass sheet constituting the glass panel, and to reduce the strength of the original tempered glass sheet. Is to provide a glass panel that can reliably secure the glass panel.
[0007]
[Means for Solving the Problems]
According to a feature of the first aspect of the present invention, a pair of tempered glass sheets are disposed to face each other via a gap, and the peripheral edges of the tempered glass sheets are directly joined to each other with a metal material to hermetically seal the gap. In the glass panel, the warpage amount in the thickness direction of the both reinforced glass sheets with respect to a unit length of 100 mm in the direction along the peripheral edge is X (mm), and the surface compressive stress of each reinforced glass sheet is defined as A (kg / cm ² ) and plate thickness as t (mm)
(Equation 2)
Xt ≦ (A + 800) / 650 × (4 / t) ³ × 0.1
Is where you meet.
[0008]
That is, when producing a glass panel using a pair of tempered glass sheets, as long as the above-mentioned amount of warpage X in each tempered glass sheet satisfies the above-mentioned equation, as will be apparent from various experimental results described later, the impact on the glass panel Is applied, it is possible to avoid crushing from the peripheral edge of the reinforced glass sheet by an impact force less than the crushing limit stress inherent in each reinforced sheet glass, and therefore, it is possible to improve the strength of the entire glass panel.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a glass panel according to the present invention will be described with reference to the drawings.
As such a glass panel, for example, there is a vacuum double glazing. As shown in FIG. 1, the vacuum double glazing P is a pair of tempered glazings 1 and 2 reinforced by heating. , 2 are disposed so as to face each other with a gap V between the tempered glass sheets 1, 2 by interposing a number of spacers 3 therebetween. The periphery is directly joined by solder 4 which is an example of a metal material, and a gap V between both reinforced glass sheets 1 and 2 is hermetically sealed under reduced pressure.
[0010]
A transparent float glass having a thickness t of about 2.65 to 3.2 mm is used for both the tempered glass sheets 1 and 2, and the gap V between the tempered glass sheets 1 and 2 is 1.33 Pa (1.0 mm). In order to reduce the pressure by reducing the pressure in the gap V by reducing the pressure to 10 ⁻² Torr or less, one of the strengthened glass sheets 1 is provided with a suction unit 5.
As shown in FIG. 2, the suction part 5 includes a circular suction hole 5a formed in one of the strengthened glass sheets 1, a glass tube 5b fixed to the suction hole 5a, and a cap 5c covering the glass tube 5b. After the gas in the gap V is sucked from the thin glass tube 5b and decompressed, the end of the thin glass tube 5b is sealed by heating and a cap 5c is attached.
The spacer 3 preferably has a columnar shape, and has a compressive strength of 4.9 × 10 ⁸ Pa (5 × 10 ³ kgf / cm ² ) or more so as to withstand the atmospheric pressure acting on both reinforced plate glasses 1 and ² . It is formed of a material, for example, stainless steel (SUS304) or Inconel 718, and has a diameter of about 0.3 to 1.0 mm and a height of about 0.15 to 1.0 mm. Is set to about 20 mm.
[0011]
The solder 4 that seals the peripheral portions of the reinforced glass sheets 1 and 2 contains Sn, Zn, Ti, and the like. For example, 72.0 to 99.9% of Sn, 0.1 to 10.0% of Zn, A material composed of 0.001 to 3.0% Ti and containing less than 0.1% or substantially no Pb is used.
However, in addition to the above-mentioned components, for example, In is added to the solder 4 in order to lower the melting point of the solder and to improve the wettability to the reinforced plate glasses 1 and 2, Ag can be added to improve the mechanical strength. In addition, Bi, Sb, Fe, Ni, Co, Ga, Ge, P, etc. are used to improve the wettability and mechanical strength of the solder. Can be appropriately added, and solder composed of various components can be used.
[0012]
Such a solder 4 is filled in the gap between both tempered glass sheets 1 and 2 by a dedicated solder filling tool 6 shown in FIGS. 3 and 4, and the solder filling tool 6 is placed on a base 7 for forming a glass panel. It is provided with a supply tower 8 which is installed and moves along the periphery of the tempered glass sheets 1, 2, and an introduction plate 9 which is provided to protrude from the lower end side of the supply tower 8 to the side, and the like. The thickness is very thin (about 0.1 mm) and formed in a flat shape that is long in the lateral direction.
The supply tower 8 includes a crucible portion 8a for storing molten solder (including unmelted one) 4A, an electric heater 8b for heating and keeping the temperature of the crucible portion 8a, an outlet 8c where the introduction plate 9 is located, and a crucible portion 8a. An introduction plate 9 which is provided with a lead-out path 8d connecting the bottoms and the like, moves on a rail 7a provided on the base 7, and moves along with the supply tower 8 so as to be inserted into the gap V between the tempered glass sheets 1, 2. The molten solder 4A is supplied over the entire length of the peripheral portions of both the reinforced plate glasses 1 and 2, and the peripheral portions of the both reinforced plate glasses 1 and 2 are directly joined to hermetically seal the gap V. .
[0013]
As described above, when the molten solder 4A is supplied to and bonded to the peripheral portions of the tempered glass sheets 1 and 2, if the peripheral edges of the tempered glass sheets 1 and 2 are warped in the thickness direction of the tempered glass sheets 1 and 2. Due to the wettability of the solder 4A to the reinforced glass plates 1 and 2, the bonding strength of the reinforced glass plates 1 and 2 is reduced, and it becomes difficult to maintain the airtightness of the gap V.
Therefore, conventionally, from the supply of the solder 4A to the solidification of the solder 4A, as shown in FIG. (The dashed line in the figure indicates a warped state), and the peripheries of the tempered glass sheets 1 and 2 are joined while the warpage is corrected. For this reason, internal stresses associated with the correction of the warp remain at the peripheral portions of the reinforced plate glasses 1 and 2, and the strength of the vacuum double glazing P decreases due to the remaining internal stress.
[0014]
The present invention focuses on the residual internal stress accompanying the correction of the warp, and is based on a novel conclusion obtained based on the results of repeated experiments and analyzes.
To explain an example of the experiment, a pair of tempered glass sheets having a plate thickness of 4 mm and having almost no warp at the peripheral portion was used, and a vacuum double-glazed glass having a side of 350 mm was produced by the above-described method. A 1 kg sphere was dropped freely from a height of 600 mm near the center of the vacuum insulated glass, and the maximum principal stress generated in the strengthened glazing on the falling side was measured to obtain the result shown in FIG.
In this table, the vertical axis represents the maximum principal stress (Pa), the horizontal axis represents time (seconds), and L represents the original limit stress at which the strengthened sheet glass is broken. The dotted line indicates the stress in the vicinity of the falling point of the sphere, and the solid line indicates the stress at the peripheral edge on two sides of the square strengthened glass sheet.
[0015]
As is clear from the chart shown in FIG. 6 (a), near the drop point of the sphere, the stress rapidly increases immediately after the sphere falls, and a stress exceeding 1.9E + 08 (Pa) occurs at the maximum peak, After that, it rapidly decays and again reaches a small peak.
On the other hand, in the peripheral portion, a rapid increase in stress is not seen immediately after the sphere drops, and after a time lag, the maximum peak is reached, and the maximum stress is about 4.5E + 07 (Pa).
Therefore, it can be understood that if there is no warpage in the peripheral portions of both tempered glass sheets, when a large impact force acts on the tempered glass sheets constituting the vacuum double-glazed glass, the tempered glass sheets are crushed from near the drop point of the sphere.
[0016]
Similarly, a pair of tempered glass sheets having a thickness of 4 mm with a warped edge, specifically, a tempered glass sheet having a warp amount X (see FIG. 5) of 0.2 mm per unit length of 100 mm in a direction along the peripheral edge. Was used to produce a vacuum double-glazed glass having the same dimensions, and the same experiment as described above was performed to obtain the results shown in FIG.
According to this chart, an initial stress of about 1.6E + 08 (Pa) remains at the peripheral edge of the reinforced sheet glass due to the correction of the warp. Therefore, the maximum stress near the drop point is less than the critical stress L of the reinforced sheet glass. Nevertheless, it can be understood that the maximum stress at the peripheral edge exceeds the limit stress L, and the reinforced sheet glass fractures from the edge.
Therefore, if the residual initial stress in the peripheral portion due to the correction of the warp is suppressed to a low level, it is possible to avoid crushing of the tempered sheet glass from the peripheral portion in the vacuum double glazing.
[0017]
The residual initial stress of the peripheral portion due to the correction of the warp, of course, changes based on the above-described warp amount X. FIG. 7 shows that these relationships are obtained from the experimental results, which vary depending on t.
In this chart, the vertical axis represents the amount of warpage X (mm) with respect to a unit length of 100 mm, the horizontal axis represents the surface compressive stress A (kg / cm ² ), and the thickness t of the four types of strengthened sheet glass from 3 mm to 6 mm. As a result, each broken line indicates a limit in the plate thickness t, that is, a limit in avoiding crushing from a peripheral edge portion in a strengthened plate glass constituting a glass panel such as a vacuum double glazing.
[0018]
According to other experimental results including the experimental result of FIG. 7, when the thickness t of the reinforced sheet glass is 4 mm, the stress generated with the amount of warpage X (mm) in the peripheral portion with respect to a unit length of 100 mm is 650 (kg / kg). cm ² ).
Therefore, from the experimental results so far, when the sheet thickness t is 4 mm, the warpage amount X (mm) allowed for the reinforced sheet glass is as follows, assuming that the surface compressive stress of the reinforced sheet glass is A (kg / cm ² ). become.
[0019]
[Equation 3]
X ≦ (A + 800) /650×0.1
[0020]
Since the generated stress is inversely proportional to the cube of the plate thickness, if the plate thickness is t (mm), the following formula is established.
[0021]
(Equation 4)
Xt ≦ (A + 800) / 650 × (4 / t) ³ × 0.1
[0022]
Therefore, as long as the above-mentioned warpage X (mm) is within the range satisfying this equation, in a vacuum double glazing formed by using the tempered glass sheet, an impact is applied near the center of the vacuum double glazing. However, the particles are not crushed from the peripheral portion, but are crushed from near the impact.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view of a vacuum insulating glass. FIG. 2 is a cross-sectional view of the vacuum insulating glass. FIG. 3 is a cross-sectional view showing a manufacturing process of the vacuum insulating glass. FIG. 5 is a partially cutaway plan view showing the manufacturing process. FIG. 5 is a cross-sectional view schematically showing the manufacturing process of the vacuum insulated glass. FIG. 6 is a table showing the impact test results of the vacuum insulated glass. Chart showing the relationship between the amount of warpage and the surface compressive stress [Explanation of symbols]
1, tempered glass 4 metal material P glass panel V gap

Claims (1)

A glass panel in which a pair of tempered glass sheets are arranged to face each other via a gap portion, and the gap portions are hermetically sealed by directly joining peripheral edges of the both tempered glass sheets with a metal material,
In the peripheral portions of the both reinforced glass sheets, the amount of warpage in the thickness direction of the both reinforced glass sheets with respect to a unit length of 100 mm in the direction along the peripheral portions is X (mm), and the surface compressive stress of each reinforced glass sheet is A (kg / cm ^2). ), And the plate thickness is t (mm),

Meet the glass panel.

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