Background and Field of the Invention This invention relates to a vacuum insulated glass and method of producing vacuum insulated glass.

Vacuum insulated glass (VIG) comprises two glass panels and a vacuum therebetween and it is known that the VIG can drastically reduce heat loss. However, the cost of producing VIG using existing production methods is relatively high.

It is an object of the present invention to provide a vacuum insulated glass and method of producing vacuum insulated glass which addresses at least one of the disadvantages of the prior art and/or to provide the public with a useful choice.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided a method of producing vacuum insulated glass from first and second glass sheets, comprising (i) printing spacing material on a first glass sheet;

(ii) providing a layer of sealing material between the first and second glass sheets; and

(iii) arranging the second glass sheet on the first glass sheet with the spacing material therebetween; wherein

the layer of sealing material is configured to create a hermetical seal for sealing a vacuum between the first and second glass sheets.

An advantage of the described embodiment is that time for producing the vacuum insulated glass is reduced (i.e. shorter process time) and at lower costs too. The method may further comprise (iv) creating a vacuum between the first and second glass sheets and heating the layer of sealing material to create the hermetical seal. Preferably, the sealing material includes polymer seal.

For better alignment, the method may further comprise taping the first and second glass sheets together using temperature tape. The spacing material may include an array of dot spacer. In this case, each of the dot spacers may have a diameter of about 0.2mm to about 0.5mm. Preferably, the dot spacers are made from epoxy or ceramic. Alternatively (or perhaps in addition to the dot spacers), the spacing material may include a layer of spacing material representing an image or pattern. When heating is required, temperature of the heating is about 80°C to about 140°C. The sealing material is adhesive tape and in this case, heating may not be needed.

According to a second aspect of the invention, there is provided a vacuum insulated glass produced by the method discussed above.

According to a third aspect of the invention, there is provided a method of producing vacuum insulated glass from first and second glass sheets, comprising

(i) providing spacing material on a first glass sheet; (ii) providing a layer of polymer seal between the first and second glass sheets; and (iii) arranging the second glass sheet on the first glass sheet with the spacing material therebetween; wherein the layer of polymer seal is to be heated to create a hermetical seal for sealing a vacuum between the first and second glass sheets. According to a fourth aspect of the invention, there is provided a vacuum insulated glass comprising a first glass sheet hermetically sealed to a second glass sheet around edges of both glass sheets by a polymer seal; a vacuum between the first and second glass sheets and sealed by the polymer seal; and spacing material printed between the first and second glass sheets.

According to a fifth aspect of the invention, there is provided a vacuum insulated glass comprising a first glass sheet hermetically sealed to a second glass sheet around edges of both glass sheets by a polymer seal; a vacuum between the first and second glass sheets and sealed by the polymer seal; and spacing material provided between the first and second glass sheets.

According to a sixth aspect of the invention, there is provided a vacuum insulated glass comprising a first glass sheet hermetically sealed to a second glass sheet around edges of both glass sheets by a sealing material; a vacuum between the first and second glass sheets and sealed by the sealing material; and spacing material printed between the first and second glass sheets. The spacing material of the above discussed aspects may include an array of dot spacers or a layer of spacing material representing an image or pattern. It should be appreciated that features relating to one aspect may also be applicable to the other aspects.

Brief Description of the Drawings

Examples of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a flow chart of a method of producing vacuum insulated glass according to a preferred embodiment of the invention;

Figure 2 is a schematic diagram of a first glass sheet printed with an array of support spacers and has a layer of polymer seal around a border of the first glass sheet which is created based on the method of Figure 1 ;

Figure 3 is a schematic diagram the first glass sheet of Figure 2 with a second glass sheet arranged on top; and

Figure 4 is a photograph of a vacuum insulated glass produced from the method of Figure 1. Detailed Description of Preferred Embodiment

Figure 1 is a flow chart illustrating steps of a method 100 for producing vacuum insulated glass (VIG) 200 (see Figure 4) from a first glass sheet 202 and a second glass sheet 204 according to a preferred embodiment of the invention. The first and second glass sheets 202,204 are rectangular in shape. Needless to say, other shapes are possible. At step 102, the method 100 includes printing spacing material in the form of an array of support/dot spacers or pillars 206 on a surface 208 of the first glass sheet 202 using a printing machine and leaving a border 210 near each edge of the glass sheet 202 unprinted. In this embodiment, the support spacers 206 are made of epoxy, and each has a diameter of about 0.2mm - 0.5mm. The support spacers are spaced apart from each other equidistantly, although this may not be so. Instead of epoxy, ceramic, polymer or other printable materials may also be used for the support spacers.

Next, at step 104, a layer of polymer seal 212 such as but not limited to lonaplast, Polyvinyl butyral (PVB), Ethylene-vinyl acetate (EVA), Thermoplastic polyurethane (TPU) and other polymer materials, is placed on the border 210 around the first glass sheet 202 and Figure 2 is a schematic diagram of the first glass sheet 202 with the printed support spacers 206 and the layer of polymer seal 212. At a subsequent step 106, the second glass sheet 204 is placed on the array of support spacers 206 and the polymer seal 212 with edges of the second glass sheet 204 aligned with the edges of the first glass sheet 202. This arrangement is shown in Figure 3 with a section of the second glass sheet 204 cut away to show the support spacers 206 and the polymer seal 212 between the two glass sheets 202,204. In other words, the support spacers 206 separate the two glass sheets 202,204 and are arranged to create a space between the two glass sheets 202,204.

At step 108, the glass sheets 202,204 are taped together on each edge of the glass sheets 202,204 using temperature tapes to form an intermediate glass assembly 250. At step 110, a vacuum is created between the two glass sheets 202,204. For this step, the intermediate glass assembly 250 is first placed in a vacuum bag and the vacuum bag is then placed in an oven. Next, the vacuum bag is connected to a vacuum system outside the oven via a vacuum tube. Once the pump down is completed , typically below about 1 X 10-4 torr, heating elements of the oven are turned on to heat the vacuum bag and the glass assembly 250 to a temperature and for a period of time for the polymer seal 210 to soften and bonds to both the two glass sheets 202,204. In other words, the heating heats the polymer seal 210 to create a hermetical seal around the vacuum created between the two glass sheets 202,204 and to seal the vacuum. For typical polymer seals, the temperature is between 80 and 140 °C for the bonding to take place.

It should be appreciated that the oven's parameters should be controlled to control the heating time after the pressure of the vacuum is reached the desired level for the proper sealing to take place. A photograph of the VIG 200 produced using the method 100 is shown in Figure 4. To measure thermal resistance, R-value, of the VIG 200, the VIG 200 is used as a window for a room with the following conditions:

a) room side temperature of about 23.8°C;

b) room airflow velocity of about 0.3m/s;

c) outdoor temperature of about 34.8°C;

d) outdoor airflow velocity of about 4.3m/s.

The measurement shows that the thermal transmission U-value of the VIG is 1.8W, which is equivalent to a U-value (heat transfer coefficient) of 1.8 W/m ² K.

With the proposed method, this reduces production time for producing the VIG 200 and at a much lower costs. The use of the polymer seal 212 is particularly advantageous since it has a lower sealing temperature than other types of seals, such as solder glass edge seal. This achieves savings in costs and energy and makes the method more time efficient.

It should be appreciated that the closer the distance between the support spacers, the better it is for the support spacers to maintain the separation between the two glass sheets 202,204 and for the VIG 200 to withstand large forces due to atmospheric pressure.

Also, different types of glass may be used to form the VIG 200, such as clear glass, tempered glass or frosted glass etc. Further, although the described embodiment describes producing the VIG using two glass sheets or panels, further sheets or panels of glass may be used so that the VIG has triple or multiple layers of glass, depending on application.

The printing of the support spacers 206 and/or the polymer seal 212 may be done on the second glass sheet 204, instead of the first glass sheet 202. Also, the printing of the support spacers 206 may be done on one glass sheet and the polymer seal provided on the other glass sheet. Further, the spacing material may not include the array of dot spacers 206. Instead, the spacing material may take the form of an image or pattern which functions similar to a spacer and sandwiched between the first and second glass sheets 202,204. In this way, the image or pattern is thus visible through the glass sheets 202,204. It is preferred to print the support spacers 206 and to use the polymer seal for creating the hermetical seal. However, other types of sealing material such as solder glass or adhesive tapes may also be used. If adhesive tapes are used, then these need not be heated in order to form the hermetical seal for sealing a vacuum. Likewise, the polymer seal may also be used with other types of support spacers which are not necessary printed.

Having now fully described the invention, it should be apparent to one of ordinary skill in the art that many modifications can be made hereto without departing from the scope as claimed.