Effects of forming and cooling temperature on the opaque properties of translucent opal glass for the glass diffuser of LED lighting

Translucent opal glass was fabricated in order to substitute polycarbonate diffuser of LED lighting for the purpose of improving the durability problem. Calcium phosphate was used for the opacifier of opal glass and melted at 1550 degrees C for 2 hrs in electric furnace. Because opal glass was made by phase separation and growth of opacifier grains during cooling procedure after forming of melted glass, we identified the effect of opaque properties by the change of forming and cooling temperature, as R.T. (room temperature), 850 degrees C, 1100 degrees C and 1200 degrees C. As the results, it had excellent optical properties for the diffuser of LED lighting in the fabricated sample of forming and cooling at 1200 degrees C, with no dazzling from direct light by high haze value over 82 % and low parallel transmittance value under 10 %. For the thermal properties, it had expressed thermal expansion coefficient of 6.352 x 10(-6)/degrees C and softening point of 839 degrees C.