Patent attributes
Proposed is an illumination device (1), comprising a semiconductor light source (10) for generating light, a primary optical system (20) for feeding the light to a secondary optical system (30), which is provided for radiating the light and for achieving a desired radiation pattern. The semiconductor light source may comprise LEDs and/or Laser-Diodes. The primary optical system comprises a light-guide with a mirrored end-face (24) and an out-coupling structure (25) for directing light into the secondary optical system. The mirrored end-face optically folds the light-guide, effectively extending the length over which the light is advantageously homogenized inside the light guide. Furthermore, optically folding the light-guide makes more economical use of the space inside the secondary optical system. This is especially advantageous when designing an LED based retrofit for existing form factors of halogen based illumination devices.