Hot Mirrors

Hot mirror coating that is deposited on the glass acts as a dichroic coating which transmits visible and reflects NIR. Hot mirror by name reflects the heat radiation (IR) while transmitting the cool light (Visible) is designed for use in systems that have an extended range heat sources like halogen lamp. Their performance is equivalent to heat absorbing filters. But reflects the light energy back on to the source instead of absorbing the heat radiation. This coating when applied on the halogen lamp surface, reflects the heat energy back on to the filament and helps in increasing the temperature of the filament.   As a result, filament temperature rises and it draws less current than those without coating to generate the same output. Hence, lamp efficiency will increase and power consumption will reduce.