Low-E glass can be divided into online high-temperature pyrolytic deposition and offline vacuum magnetron sputtering processes.
Online High-Temperature Pyrolytic Deposition: This method is completed during the cooling process of float glass. Liquid metal or metal powder is directly sprayed onto the hot glass surface, and as the glass cools, the metal film layer becomes part of the glass. This type of glass has a single variety, poor heat reflection, and low manufacturing cost. Its only advantage is that it can be hot-bent, tempered, and does not need to be used in a hollow state; it can be stored for a long time.
The disadvantage is its poor thermal performance. Unless the film layer is very thick, its "U" value is only half of the sputtering "Low-E" coated glass. If you want to improve its thermal performance by increasing the film thickness, its transparency will be very poor.
Offline Coated Glass: Offline coated glass comes in a variety of colors, has excellent heat reflection performance, and obvious energy-saving characteristics. Its drawback is that it cannot be hot-bent.
Offline Vacuum Magnetron Sputtering: The production of Low-E glass by offline methods commonly uses vacuum magnetron sputtering coating technology. Unlike high-temperature pyrolytic deposition, sputtering is done offline, and there are horizontal and vertical distinctions depending on the glass transmission position.
It offers a variety of colors, excellent heat reflection performance, and obvious energy-saving characteristics. Different products with high, medium, and low transmittance can be produced according to different climate characteristics. Colors include silver-gray, light gray, light blue, and colorless transparent. The drawback is that it cannot be hot-bent, and the silver oxide film layer is very fragile. Therefore, it cannot be used like ordinary glass. It must be made into insulating glass, and it is not suitable for long-distance transportation before being made into insulating products.
Note: Low-E glass manufactured by offline vacuum magnetron sputtering cannot be used as a single piece; it can only be synthesized for use in insulating glass or laminated glass. However, its emissivity (E) is far below 0.15, even as low as below 0.01.
Online coated glass can be used as a single piece, but its emissivity (E = 0.28) cannot strictly be called Low-E glass (scientifically, objects with an emissivity E ≤ 0.15 are considered low-emissivity objects).
