Germany : Coated BOROFLOAT glass substrates for customized light management design.
High quality functional coatings enable a large variety of customized light management design options especially when based on a reliable substrate material such as BOROFLOAT borosilicate glass. This flat glass from specialty glass expert SCHOTT is manufactured in a sophisticated float process and simultaneously offers convincing optical, thermal, mechanical and chemical properties. It is a well suited material for use in optical components such as dichroic filters or hot and cold mirrors that rely on high thermal resistance as well as on high energy radiation exposure capabilities.
Dichroic filters, also called inference filters, are based on the ability to reflect and absorb only certain wavelength ranges, making them ideal for use in high intensity light sources or light engines. They feature in architectural and entertainment lighting solutions, color wheels, light performance correction, electronic devices, heat and UV control applications, underwater lighting, medical photonics and many other optical applications. Dichroic filters originated in the 1950s: the NASA developed them to protect sensitive spacecraft instruments from harmful cosmic radiation.
The performance of a dichroic filter is determined not only by the quality of its coating, but also by the substrate material itself. Both the substrate s optical properties as well as its temperature resistance determine the efficiency and maximum operation temperature of the filter product. BOROFLOATA glass in a coated dichroic filter has a high thermal resistance and can reach up to 287AC (550AF) in typical applications. It also shows low transmission losses under UV radiation exposure, meaning a low susceptibility towards solarisation. It may also withstand thermal gradients and combines superior optical clarity with mirror-like surface quality.
Due to its unique glass microstructure with a relatively low amount of non-bridging oxygens, BOROFLOATA glass shows a low degradation behavior at high intensity radiation exposure rates. This means that dichroic filters made of BOROFLOATA glass often exhibit significantly better color filter characteristics (for instance steep UV cut-off performance, higher level of visible transmittance). Moreover, high laser and X-ray radiation damage threshold characteristics can contribute to longer lifetimes and better overall performance compared to other flat glass substrates under such challenging conditions.
In contrast, many conventional flat glass materials used as filter substrates show lower performance, making them less suitable for use in dichroic filters: for instance, dyed plastics or commercial glass types have limited thermal resistance.
Plastic colored materials often suffer from non-desirable aging effects (yellowishing) and even may break down if illuminated with high energy light.
[c] 2015 Al Bawaba (Albawaba.com) Provided by SyndiGate Media Inc. ( Syndigate.info ).
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|Date:||Nov 25, 2015|
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