ANGULAR DEPENDENT ELEMENT POSITIONED FOR COLOR TUNING

摘要

A light emitting device includes a light source that produces light having a range of wavelengths and an angular dependent element that filters the light. The angular dependent element, may be, e.g., a dichroic filter, dichroic mirror, a cholesteric film, a diffractive filter, and a holographic filter. The angular dependent element having one or more ranges in which wavelengths of light are more efficiently propagated than wavelengths of light that are not within the one or more ranges. The angular dependent element is positioned at an angle with respect to the optical axis. By adjusting the angular position of the angular dependent filter with respect to the optical axis, the wavelengths of light produced by the light emitting device can be controlled to select a desired color of light.