Light refining or purifying device e.g. for image projection

摘要

The light refining device has a flat plate with a high reflective wide-band mirror on one side. The other side of the flat plate is made up of a reflection reducing coating section and at least one dichroic mirror section. At least two light beam of a two different wavelengths are incident at an angle to the perpendicular. The first beam passes through the reflection reducing coating which only transmits light of the first wavelength. The second beam passes through the dichroic mirror which only transmits light of the second wavelength. In the air gap within the flat plate the first beam is reflected by the wide-band mirror and the dichroic mirror and joins the second beam. The process can be repeated for a third wavelength. Finally the refined beam is output via a reflex reducing wide band coating.