Multi color LED Theatre spot with zoom function

Theatre spots currently use Halogen lamps as light source and typical wattages range from 500 to 1000W. We have built a multi color LED module in the most often used Theatre spot fixture, the Source Four from ETC and we have modified the optical system in order to get homogeneous color mixing. With the modified optical system, the gobo projection, hard edge spot beam and zoom functionality were still operational as in the original Source Four. In addition the multi color LED module enabled a large variety of colors and white light with any color temperature between 2500K and 6500K with a CRI of around 90. The main advantage of the use of LEDs in theatre fixtures is related to the creation of colors. Colored light is currently made by Halogen lamps combined with filters absorbing part of the spectrum. Some frequently used filters transmit only a few percent of the light, so the use of LEDs can lead to considerable energy saving. Further cost saving is achieved because of the long lifetime of LEDs. In addition, LEDs enable new light effects like controlled color transitions and instant black out.