Displays, printed circuit boards and passive components
AEROSIL®, AEROXIDE® and AERODISP® are highly versatile products, delivering various functions for electronics applications.
AERODISP® homogeneous dispersions of fumed silica or fumed metal oxides are added in the polymerization process for optical films as anti-blocking agents in order to prevent the layers of polymer film to stick to each other.
If optical films are coated with a hardcoating resin formulation containing AERODISP® dispersions, the mechanical and optical properties of the film can be modified according to the requirements of the application. Various effects can be achieved due to the properties of the particles contained in the AERODISP® dispersions, among which the most prominent are anti-blocking, anti-glare, anti-scratch and refractive index modulation.
Printed circuit boards and passive components
Printed circuit boards (PCB) undergo a number of production steps, before being finally put to use in today’s electrical goods. One important step is to ensure that the conductive wires are clear from imperfections.
Typically AEROSIL® products are used as additives to control the rheology of special etch resistant inks, therefore ensuring the conductive wire is fully protected during the etching process. At the same time, etch resist inks protect the circuit from environmental conditions, such as heat, moisture and dust.
Multilayer Ceramic Capacitors (MLCCs) have been used widely in electronic circuits today because of their ability to temporarily store an electrical charge and decouple noise. Typical MLCCs are composed of a ceramic dielectric, inner electrode and termination. The manufacture of MLCCs consists of several steps including the sintering process of the ceramic powder into a dense ceramic body. With a small dosage of AEROSIL® fumed silica or AEROXIDE® fumed metal oxides acting as sintering aid, the sintering temperature can be reduced while the high density, homogeneous fine-grained microstructure, and the excellent dielectric properties can be maintained.
Barium Titanate (BT) is one of the well-known materials used for MLCCs because of its high dielectric constant. Barium titanate can be produced by a number of processes; one of the most economical methods is production via a solid state process, without compromising performance. AEROXIDE® fumed titanium dioxide can be used as the seed to synthesize BT powder.
The encapsulating material together with phosphor for LED packaging plays a very important role in determining performance. Phosphors typically come in powder form and are dispersed into a liquid encapsulant, e.g. epoxy or silicone, by different weight ratios. The phosphor particles tend to settle inside the phosphor/liquid encapsulant mixture during the dispensing/curing processes, thereby providing a non-uniform distribution of phosphor throughout the cured encapsulant, which exhibits a yellow white or bluish white color of white LEDs. AEROSIL® surface treated silica products show good anti-sedimentation performance for phosphor in LED encapsulants, while maintaining transparency at a high level.
When LED input power increases, the substrate has to be capable of dissipating more heat generated from the LED die to the environment. Ceramic substrates are suitable for high power LEDs to support rapid heat dissipation. Silicon carbide (SiC) or aluminum nitride (AlN) are two suitable materials as ceramic substrates with good thermal conductivities and compatible coefficients of thermal expansion (CTE). AEROSIL® hydrophilic fumed silica and AEROXIDE® fumed alumina of high purity can be used as raw materials for the production of SiC or AlN powder.
LED phosphors are key materials for the luminous efficiency, service life, and color rendering index (CRi) for LED lighting. The development of LED phosphors started from less stable sulfide and halide. Further on aluminate of high temperature and chemical stability, silicate, nitride and oxynitride fluorescent materials have entered the market. AEROSIL® hydrophilic fumed silica and AEROXIDE® fumed alumina of high purity can work as key components in the phosphor crystal lattice to provide the covalence (changing ligand sharing electrons with activator) and crystal field adjustment (changing crystal structure) for silicate or aluminate phosphors.