More than 3,000 years ago, when the Phoenicians mixed quartz sand with natural soda and melted it in a special furnace to make glass balls. Colorless glass was also produced in China by 1000 BC. In the 12th century AD, commercial glass appeared and began to become an industrial material. In the 18th century, in order to meet the needs of developing telescopes, optical glass was produced in Western Europe. In 1906, after the flat glass machine was produced in the United States, with the industrialization and scale of glass production, glass of various uses and properties came out one after another.

  Nowadays, as an important material in the construction industry, the usage of glass is increasing rapidly. People's requirements for glass are no longer just on its appearance. Wind and cold protection are only its basic functions, and glass's heat control, cooling cost and internal sunlight projection comfort balance have become new themes of technology research and development. As a result, Low-E coated glass stands out as an upstart in the glass family and quickly attracts people's attention.

What is Low-E glass

 The heat lost through doors and windows in a building accounts for about 50% of the heating or cooling energy consumption of the entire building, while the heat lost through glass accounts for about 80% of the heat lost through the entire window. important part. Therefore, architectural glass with excellent lighting performance and thermal insulation performance has always been a major research hotspot in the industry. Under such an industry background, Low-E glass (Low Emissivity Glass) came into being.

 Low-E glass is low-emission coated glass, a kind of coated glass with high reflectance to far infrared rays in the wavelength range of 4.5μm to 25μm.

Low-E glass is a member of the coated glass family, and its wide application began in developed countries in Europe and the United States in the 1990s. In architectural applications, the use of Low-E glass can achieve the effect of "warm in winter and cool in summer", with excellent thermal insulation and thermal insulation performance. People in the industry also call it thermostatic glass: that is, no matter how much the indoor and outdoor temperature difference is, as long as the Low-E glass is installed, the indoor air-conditioning cost can be maintained forever warm in winter and cool in summer.

Classification of Low-E Glass

  The surface emissivity of ordinary glass is about 0.84, which means that ordinary glass can radiate back 16% of the far-infrared heat energy of sunlight. According to the different processing technology and Low-E film, Low-E glass can be divided into online Low-E glass and offline Low-E glass.

  The emissivity of online Low-E glass is generally less than 0.25, which means that more than 75% of the far-infrared heat energy of sunlight can be reflected back; the emissivity of offline Low-E glass is generally less than 0.15, and the emissivity of three-silver hollow Low-E glass is generally less than 0.15. It can reach 0.02, which means that Sanyin hollow Low-E glass can reflect 98% of the far-infrared heat energy of sunlight, which can well block the penetration of thermal radiation.

  Therefore, Low-E glass has high reflectivity for infrared rays and high transmittance for visible light. The Low-E glass made has low heat transfer coefficient and excellent shading effect, which not only saves energy, but also improves the building's performance. comfort.

Application of Low-E Glass

 The online Low-E glass film layer has high hardness, good mechanical strength and can be thermally processed. However, due to the thick film layer, the color is not flexible and relatively single, and the emissivity is generally between 0.15 and 0.25. Offline Low-E glass is a metal film layer and other dielectric film layers plated by magnetron sputtering method, usually by magnetron cathode sputtering method, when the glass substrate is transferred to the coated glass production line. Magnetron cathode sputtering occurs in a static electromagnetic field, electrons are accelerated to the glass substrate at the anode under the action of Lorentz force, and collide with Ar atoms in the atmosphere. When the energy of the electrons is large enough, Ar atoms ionize Ar+ and electronics. The electrons fly to the substrate, Ar+ accelerates to the cathode (sputtering target) and bombards the target with high energy, sputtering occurs, the neutral particles in the sputtering particles are deposited on the substrate to form a thin film, and the secondary electrons are in the electromagnetic field. Under the action of the Lorentz force, the compound motion of cycloid and spiral is performed. Off-line Low-E glass produced by magnetron cathode sputtering has flexible color and lower emissivity than on-line Low-E glass.

 Offline Low-E glass products are widely used in building curtain walls and large area windows. In order to meet the dual characteristics of lighting and energy saving. Generally not used as a single piece, usually combined into gas-filled insulating glass or vacuum glass, the hollow cavity is filled with inert gas such as Ar or Kr, one is to protect the glass film surface from damage and prolong the service life of Low-E glass ; is to improve the energy-saving effect of glass.

- Transferred from Xinglass.com