Patent ID: 8534896

Claim:
An illumination device, arranged to generate first and second light in opposite directions, comprising a waveguide element comprising a first face, a second face, and a waveguide edge; a LED light source comprising collimating optics and arranged to generate light source light, wherein the LED light source is arranged to couple at least part of the light source light into the waveguide element via the waveguide edge of the waveguide element to provide waveguide light; a first transmissive reflector, arranged at the first face side, and a second transmissive reflector, arranged at the second face side, wherein the LED light source, the waveguide element, the first transmissive reflector, and the second transmissive reflector, are arranged to generate the first and the second light in a direction away from the first face and in a direction away from the second face, respectively; and a controllable attenuator, arranged to attenuate part of the first or second light, wherein the attenuator comprises a device with an opening with a controllable opening size.