Arc Source Multi-Layer Coatings to Double lighting System Lifetimes without Affecting Performance

The purpose of this project is to demonstrate the feasibility of using Acree Technologies' Filtered Cathodic Arc Plasma Deposition process to deposit multilayer optical coatings to the outside of High Intensity Discharge (HID) lamps to increase their lifetime and efficiency without affecting their color rendering or optical performance. To increase the life and efficiency of the HID lamps, the multilayer coatings will reflect ultraviolet (UV) and infrared (IR) radiation back into the lamp so that the glass envelope will be more uniformly heated, reducing one of the major failure mechanisms, which is fracture of the glass due to devitrification and uneven thermal expansion at hot spots. The reflected UV has the added potential of increasing the efficiency of the lamp by recycling wasted photons. In addition, a diffusion barrier top coat will be used to inhibit contaminates from reaching the glass envelope, thereby extending the life of the lamps by reducing another major failure mechanism, which is fracture of the glass envelope due to phase changes at impurity nucleation sites.