[DESCRIPTION] [invention Title]

VACUUM GLAZING AND MANUFACTURING METHOD THEREOF

[Technical Field] The present invention relates to vacuum glazing consisting of a plurality of glass sheets which are stacked one on another with an evacuated space defined therebetween, and more particularly to vacuum glazing and a method of manufacturing the same, which includes hermetically sealing a plurality of glass sheets in a vacuum atmosphere and simultaneously exhausting internal gas from between the glass sheets through gaps between seals disposed between the glass sheets.

[Background Art] Recently constructed large and small buildings including apartments, residential apartment complexes, and offices have outer walls all or part of which are finished using glass, in order to ensure an open view with a beautiful external appearance. For this purpose, glass is a material which enables the external appearance of the building to appear beautiful and diverse but which has some defects upon application to the building.

Specifically, glass having low heat insulation efficiency increases the consumption of energy compared to a concrete

wall. Thereby, as the use of glass increases in the building, devices providing shade against the sun such as blinds, vertical blinds and curtains should be provided, undesirably increasing the accessory expenses. In particular, glass allows the direct rays of the sun to enter and inside heat to go out, and thus acts as a main cause of losing energy from the building.

In the winter season, inside heat escapes out of the building through glass and thus the heating cost is increased. In the summer season, outside heat enters the building through glass, thus increasing the cooling cost.

A window using glass plays an important role in allowing communication of the inside of building with the outside of the building but has heat conductivity at least 10 times lower than generic walls.

As for the domestic energy consumption, the total energy consumption in buildings constitutes about 30% of the entire national energy consumption, and about 40% of the energy consumption of the building is lost through windows . Further, in Korea which has a 98% dependence on energy imports, heat insulation efficiency of the building as pertains to windows is essentially required to be increased in order to save energy, v ^τ hich is considered to be directly linked with enhancement of the competitiveness of the national economy.

Accordingly, double glazing is receiving attention these days in lieu of single glazing.

Double glazing is obtained by placing a film having high tensile force between two glass sheets and then performing compression or by forming a dry air layer between two glass sheets. In the latter case, when such a dry air layer is provided in an evacuated state, the resulting glazing is referred to as vacuum glazing.

FIG. 1 is a perspective view (a) and a cross-sectional view (b) showing vacuum glazing according to a conventional technique.

As shown in the drawing, the vacuum glazing 90 according to the conventional technique is configured such that two glass sheets 91, 92 which are separated with spacers 94 (support pillars) disposed therebetween are hermetically sealed with an edge seal 93 therearound and the internal air is exhausted via an exhaust tube 95 formed in the glass sheet, leading to an evacuated state.

However, in the case wh^re the vacuum glazing 90 is made of low-E glass, hard type low-E glass may be used in the form of a single sheet, whereas soft type low-E glass having a higher radiative heat shielding efficiency than hard type low-E glass is difficult to use. The reason is as follows.

That is, in the course of manufacturing the vacuum glazing, when the glass sheets 91, 92 are heated to about 450 ^° C in

the air to melt the seal 93 between the glass sheets 91, 92, the Ag metal coating film of soft type low-E glass may be oxidized, undesirably charging the color thereof and losing the radiative heat shielding function. Alternatively, the case of using electrochromatic glass or glass having a solar cell substrate incurs a problem because the metal coating film thereof may be oxidized, as in the soft type low-E glass above.

With the goal of solving this problem, as the seal 93 of the vacuum glazing 90, indium or indium alloy having a low melting point may be used, so that two glass sheets may be sealed at about 200 ^° C. In this case, however, the price of the vacuum glazing 90 is increased due to the use of indium or indium alloy. Also, while the gas, which is not sufficiently exhausted through the exhaust tube 95 but remains due to low-temperature sealing, is gradually degassed, the internal vacuum level may be lowered, and thus, the heat insulation function may disappear within several years. Moreover, the manufacture of the vacuum glazing 90 requires an additional exhaust procedure for internal evacuation, thus causing the manufacturing process thereof to be complicated, and further, the exhaust tube 95 for exhausting the internal air is provided to protrude from the surface of the vacuum glazing, making it difficult to load

masses of the vacuum glazing. [Disclosure] [Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and the present invention provides a method of manufacturing vacuum glazing in which the function thereof is not deteriorated even with the use of any one functional glass selected from among soft type low-E glass, electrochromatic glass and glass having a solar cell substrate and which also has a stronger vacuum formed between two glass sheets which is maintained for a longer period of time.

In addition, the present invention provides a method of manufacturing vacuum glazing in which hermetical sealing of glass sheets in a vacuum atmosphere and exhaust of internal air from the glass sheets are simultaneously performed, thus obviating a need for an additional exhaust process and for forming an exhaust opening and an exhaust tube.

In addition, the present invention provides vacuum glazing which includes neither an exhaust opening nor an exhaust tube or includes no exhaust tube in the presence of an exhaust opening, thus enabling the loading of masses of vacuum glazing, and in which the internal vacuum level can be maintained for a long period of time. [Technical Solution]

According to an aspect of the present invention, a method of manufacturing vacuum glazing including glass sheets which are separated with an evacuated space defined therebetween and hermetically sealed around an edge thereof and micro spacers for preventing the glass sheets from being brought into close contact with each other as a result of evacuation includes disposing the micro spacers and a plurality of frit bars produced in a bar form using glass frit as a glass material on a glass sheet which has been cleaned, placing an additional glass sheet on the frit bars disposed on the glass sheet, aligning the glass sheets and holding the aligned glass sheets to maintain alignment thereof, and heat pressing the aligned glass sheets in a vacuum atmosphere, thus hermetically sealing the glass sheets while exhausting an internal gas therefrom.

In the above method, disposing the micro spacers and the frit bars may further include disposing a getter for removing water and a gas .

As such, the getter may be a non-evaporable getter which is activated by current.

In the above method, whether the number of glass sheets is adequate is judged after placing the additional glass sheet, and in the case where the number of the glass sheets is not adequate, disposing the micro spacers and the frit bars and placing the additional glass sheet may be repeated at least

once .

In the above method, disposing the frit bars may be conducted by disposing the frit bars at an edge of the glass sheet so that gaps are formed between the frit bars which are adjacent to each other.

The frit bars may be in a degassed state.

The frit bars may have a height greater than a height of the micro spacers .

At least one of the glass sheets which are hermetically may have an opening.

In this case, heat pressing the glass sheets may be conducted by covering the opening with cover glass and then performing heat pressing.

At least one of the glass sheets may include reinforced glass, low-E glass, reflective glass, electrochromatic glass, or glass having a solar cell substrate.

According to another aspect of the present invention, vacuum glazing manufactured using the above method is provided. [Advantageous Effects]

According to the present invention, the method of manufacturing vacuum glazing includes disposing degassed frit bars at intervals between two glass sheets and then performing heat pressing in a vacuum atmosphere, thus simultaneously conducting an exhaust process and a

hermetical sealing process. Thereby, even when any one functional glass selected from among soft low-E glass, electrochromatic glass and glass having a solar cell substrate is used as the glass sheet, there is no worry about loss of functionality occurring as a result of oxidation of the metal oxide film. The internal vacuum level of the vacuum glazing can be increased, thus improving heat insulation efficiency and radiative heat shielding efficiency and allowing tht maintaining of such efficiencies for a long period of time .

The method of manufacturing the vacuum glazing according to the present invention eliminates a need for an additional exhaust process or a process of forming an exhaust opening and an exhaust tube or forming simply an exhaust tube, thus making the manufacturing process simpler and easier.

The surface of the vacuum glazing according to the present invention is flat due to the absence of the exhaust opening and the exhaust tube or without simply the exhaust tube in the presence of the exhaust opening, thus enabling the stable loading of masses of vacuum glazing and maintaining the internal vacuum level for a long period of time, resulting in a long lifespan.

[Description of Drawings] FIG. 1 is a perspective view (a) and a cross-sectional view (b) showing vacuum glazing according to a conventional

technique;

FIG. 2 is a flowchart showing a process of manufacturing vacuum glazing according to the present invention;

FIGS. 3 to 9 are views showing a process of manufacturing vacuum glazing having each of a double structure and a triple structure according to the flowchart of FIG. 2; FIG. 10 is of top plan views of FIGS. 6 and 9; and FIG. 11 is a view showing the vacuum glazing having an exhaust opening. * Description of the Reference Numerals in the Drawings * 10,40,60,91,92: glass sheet 20,50: frit bar

30,94: micro spacer 70: clip 80: cover glass 95: exhaust tube

[Best Mode] Hereinafter, a detailed description will be given of preferred embodiments of the present invention with reference to the accompanying drawings .

According to an aspect of the present invention, a method of manufacturing vacuum glazing is described. FIG. 2 is a flowchart showing the process of manufacturing vacuum glazing according to the present invention.

As shown in the drawing, the method of manufacturing the vacuum glazing according to the present invention includes 1) disposing a plurality of micro spacers and a plurality of frit bars produced in a bar form using glass frit as a glass

material on a glass sheet which is cleaned (SlO), 2) placing another glass sheet on the frit bars disposed on the glass sheet (S20), 3) aligning the glass sheets obtained in S20 and holding them to maintain the alignment thereof (S30), and 4) heat pressing the glass sheets obtained in S30 in a vacuum atmosphere, thus simultaneously exhausting internal gas and hermetically sealing the glass sheets (S40).

In the method of manufacturing the vacuum glazing according to the present invention, SlO may further include disposing a getter for removing water and gas .

An example of the getter may include a non-evaporable getter. The non-evaporable getter may be disposed inside the frit bars on the glass sheet, and a wire for supplying power to the non-evaporable getter may be provided such that the wire extends across the frit bar from the non-evaporable getter. Thereby, power can be supplied to the vacuum glazing from the outside.

In the method of manufacturing the vacuum glazing according to the present invention, after S20, whether the number of glass sheets used is adequate is judged. In the case where the number of glass sheets is not adequate, SlO and S20 may be repeated at least once (S21).

The frit bars of SlO are in a state which is degassed by removing the binder and gas from the frit used for the frit bars .

Specifically, the degassed frit bars are obtained by placing frit in a powder form or a paste form in a furnace or a jig of a vacuum chamber, heating it to remove gas and binder therefrom, and then molding the fluid frit into a predetermined shape. That is, to manufacture the frit bars, the fluid frit may be extruded using a nozzle and thus molded in a bar form. Alternatively, the frit bars may be obtained by pouring the fluid frit into a mold and then molding it. As such, it is natural that the shape of the frit bars not be limited only to a bar form.

In SlO, the frit bars are disposed at the edge of the glass sheet so that the two glass sheets are separated with an evacuated space defined therebetween. As such, it is noted that the adjacent frit bars be disposed at intervals to form predetermined gaps therebetween.

The gaps between the frit bars are used to naturally exhaust the internal air from the glass sheets obtained in S30 to the outside in S40. Through S40, individual frit bars are melted and integrated, thus sealing the glass sheets .

The height of frit bars disposed on the glass sheet should be greater than the height of micro spacers. This is because the frit bars are melted through heat pressing in S40 and thus the height thereof is lowered. However, the height of the frit bars may vary depending on the type of

material for the micro spacers, and the present invention is not limited thereto.

When the space between Lhe two glass sheets is evacuated as in typical vacuum glazing, the micro spacers function to prevent the glass sheets facing each other from warping and being brought into close contact with each other or being damaged as a result of evacuation. Thus, the array of micro spacers may variously change within a range that prevents the warpage of the glass sheets. In S40, the vacuum atmosphere is formed using a vacuum chamber for exhausting air to a vacuum level of 10 ^"2 torr to 10 ^"7 torr. As such, the vacuum chamber is provided with a heater for increasing the temperature to about 500 ^° C and a gas inflow valve for increasing the pressure. The vacuum glazing having better quality can be manufactured in proportion to an increase in the vacuum level of the vacuum chamber .

When the two glass sheets, which are aligned and held to face each other with the frit bars disposed therebetween in an atmosphere, are placed in a state of containing the air therein in the vacuum chamber, the vacuum chamber simultaneously functions to exhaust the internal gas to a desired vacuum level and to operate the heater. At this time, the internal air is sufficiently exhausted through the gaps between the frit bars disposed between the two glass

sheets, leading to a high vacuum. The vacuum level between the two glass sheets may be set to 10 ^~3 torr to 10 ^~6 torr.

When the glass sheets are heated to a predetermined temperature due to the operation of the heater, the frit bars on the glass sheet may become fluid. As such, when all of the glass sheets are pressed with clips for a predetermined period of time, the frit bars which are fluid are changed to be lower and wider and thus are charged into the gaps therebetween, thereby forming a uniform frit thickness, consequently hermetically sealing the glass sheets. Then, when the temperature of the vacuum chamber is lowered, the hermetical sealing in S40 is completed.

The temperature of the vacuum chamber heated by the heater may vary depending on the type of material for frit bars but is typically set to about 270~470 ^° C and preferably at least about 420 ^° C. The above temperature is maintained for about 10 min. It is apparent that a shorter time at a high temperature and a longer time at a low temperature will be required. FIGS. 3 to 9 are views showing the process of manufacturing the vacuum glazing having each of a double structure and a triple structure according to the flowchart of FIG. 2, in which only FIG. 3 is a perspective view and the other drawings are side views. This embodiment does not use a getter. For convenience,

the case where the number of glass sheets is two or three is described, and the number of glass sheets used for the method of manufacturing vacuum glazing according to the present invention is not limited thereto. In the method of manufacturing the vacuum glazing according to the present invention, the process of manufacturing the vacuum glazing having a double structure includes cleaning glass sheets, which are to be sealed, using alcohol thus removing an organic material from the surface thereof and then disposing a plurality of frit bars 20 produced in a bar form and a plurality of micro spacers 30 on any one glass sheet 10 of the cleaned glass sheets in SlO as shown in FIG. 3.

As seen in FIG. 3, an example of the shape of the above frit bars 20 and those frit bars which will be described later may include but is not limited to a cylindrical shape . Alternatively, useful is v polygonal pillar shape including a triangular prism or a square pillar. It is preferred that the frit bars have a shape which facilitates the alignment and manufacture of the glass sheets .

Next, as shown in FIG. 4, the glass sheet 10 having the frit bars 20 disposed thereon and another glass sheet 40 corresponding thereto are aligned so that the frit bars 20 and the micro processors 30 are located therebetween in S20. That is, another glass sheet 40 is placed on the glass sheet

obtained in SlO.

Then, whether the number of glass sheets 10, 40 obtained in S20 is adequate is judged. In this case, the number of glass sheets is two as originally intended, and thus there is no need for repeating SlO and S20.

Next, as shown in FIG. 5, the glass sheets obtained in S20 are aligned and held to maintain the alignment thereof in

S30. To this end, the aligned two glass sheets 10, 40 are held with clips 70. Finally, as shown in FIG. 6, the glass sheets obtained in

S30 are heat pressed in a vacuum atmosphere, thus simultaneously integrating the frit bars 20 to result in frit bar integration 20' and hermetically sealing the two glass sheets 10, 40 in S40. Thereby, the vacuum glazing having a double structure is completed through the method of manufacturing vacuum glazing according to the present invention.

Subsequently, the process of manufacturing the vacuum glazing having a triple structure is described below, part of which is the same as the process of manufacturing the vacuum glazing having a double structure, and thus a description thereof is omitted.

In the method of manufacturing the vacuum glazing according to the present invention, the process of manufacturing the vacuum glazing having a triple structure

includes judging whether the number of glass sheets obtained in S20 is adequate. In this case, because the number of glass sheets is not three as originally intended but is two, SlO and S20 as shown in FIGS. 3A and 3B are repeated once more in S21.

Specifically, as shown in FIG. 7, a plurality of frit bars 50 and a plurality of micro spacers (not shown) are disposed on the upper surface of the glass sheets obtained in S20, after which a further glass sheet is placed thereon. Next, as shown in FIG. 8, the three glass sheets obtained in S20 as shown in FIG. 7 are held with clips 70 so as to maintain the alignment thereof in S30.

Finally, as shown in FIG. 9, the glass sheets obtained in S30 are heat pressed in a vacuum atmosphere, thus integrating the frit bars 50 to result in frit bar integration 50' and hermetically sealing the glass sheets 10, 40, 60 in S40. Thereby, the vacuum glazing having a triple structure is completed through the method of manufacturing vacuum glazing according to the present invention.

FIG. 10 is of top plan views of FIGS. 6 and 9. As shown in the drawing, the frit bars 20, 50 of S30 are converted into the frit bar integrations 20' , 50' in terms of the array form through sealing of S40. Thereby, the space between the glass sheet 10 and the glass sheet 40 can

be seen to be hermetically sealed.

At least one of the glass sheets obtained in S40 may have an opening, which is illustrated in FIG. 6.

As shown in FIG. 11, the opening 45 is used to additionally exhaust the internal air to achieve a desired vacuum level in the case where the vacuum level between the glass sheet 10 and the glass sheet 40' is judged to be inadequate. In S40, the opening 45 is covered with cover glass 80 having a size larger than the opening 45 and then heat pressing is conducted, thereby blocking the space between the glass sheets 10, 40' from the outside. As such, in order to attach the cover glass 80, a frit molded product (not shown) which is degassed, as in the frit bars 20, 50, may be used. An example of the glass sheet typically includes but is not limited to transparent glass. Depending on the end use, at least one of the glass sheets may include any one functional glass selected from among reinforced glass, low-E glass, reflective glass, electrochromatic glass and glass having a solar cell substrate.

In particular, in the method of manufacturing vacuum glazing according to the present invention, soft type low-E glass having a radiative heat shielding efficiency and a heat insulation efficiency superior to hard type low-E glass may be applied as the glass sheet. Because the hermetical

sealing through heat pressing of the glass sheets is conducted in a vacuum atmosphere, there is no worry about the oxidation of the Ag metal coating film of the soft type low-E glass. Also, in the method of manufacturing vacuum glazing according to the present invention, electrochromatic glass and glass having a solar cell substrate, on which the metal coating film is formed as in the soft type low-E glass, may be used within a range in which functionality does not disappear due to the oxidation of the metal coating film and changes in properties thereof.

Also, glass having a solar cell substrate may be translucent or opaque due to the formation of the solar cell substrate. In this case, glass having a solar cell substrate may be provided such that it is distributed over part of the entire area of vacuum glazing to be manufactured, thus ensuring visibility.

In addition, according to another aspect of the present invention, the vacuum glazing manufactured using the above manufacturing method is provided.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention

as disclosed in the accompanying claims. [industrial Applicability]

According to the present invention, the vacuum glazing consists of a plurality of glass sheets which are stacked one on another with an evacuated space defined therebetween.

The plurality of glass sheets can be hermetically sealed in a vacuum atmosphere, and Lhe internal gas can be exhausted from the glass sheets through gaps between the seals disposed between the glass sheets, thereby increasing noise and impact reduction effects. Therefore, the vacuum glazing according to the present invention can be widely used for new buildings and renovation sites .