“…Therefore, HID lamps have been widely used for various indoor or outdoor lighting applications such as spotlights inside shopping stores, headlights of cars, LCD projectors, and small power HID lamps [1][2][3][4]. However, among these HID lamps, specially, a metal halide discharge lamp has many advantages such that consumption power is 40 % less, but light quantity and durability is three times and is four times more, respectively, compared to conventional halogen lamps, and size of light emission is small.…”