Vacuum glass is to seal two pieces of flat glass around, the gap between the two pieces of glass into a vacuum and seal the vent hole, the gap between the two pieces of glass is 0.1-0.2mm, the two pieces of vacuum glass generally have at least one piece of low radiation glass, so as to minimize the heat loss through the conduction, convection and radiation of the vacuum glass.

From the sound transmission principle, the sound insulation performance of vacuum glass is good, because the air in vacuum glass is very thin, the attenuation effect of sound wave is very good, but, vacuum glass as a sound insulation glass, there are its fatal shortcomings. It is necessary to understand the sound insulation performance of vacuum sound-proof Windows.

The first thing to figure out is the structure of vacuum glass. The glass of vacuum sound-proof window is composed of two layers of glass, in which the air is pumped out, there is a vacuum layer in the middle. The principle of sound insulation is to use the vacuum layer in the middle to cut off the way of sound transmission. Without media, sound cannot be transmitted. This is known from what we have learned about physics, so people assume that vacuum glass must be soundproof based on this principle. However, there is another important factor in the structure of vacuum glass. In the process of making vacuum glass, when the air is pumped out, the double layer of flat glass will suck together under negative pressure and lose the vacuum layer. For this reason, the vacuum glass is made with tiny brackets between the two layers of glass. These supports become sound Bridges for sound transmission -- solid sound transmission, which reduces the sound insulation performance of vacuum sound-proof Windows, especially against low frequency noise.
Secondly, vacuum glass because of gas leakage, penetration, and the gas gathered on the glass surface under the action of temperature and sunlight, from the glass surface or surface desorption, or diffusion into the vacuum layer, and then affect the service life of vacuum glass (this is and thermos after a period of use, insulation effect will gradually decay).