Patent ID: 8497639
Filing Date: 2013-07-30
Classification: F21S,F21V,F21W,F21Y

Abstract:
1. A lighting device, comprising: a housing; one or more visible-light sources for generating visible light arranged in the housing; one or more UV-light sources for generating UV-light arranged in the housing; a light exit window defined in the housing and positioned to allow transmission of the visible light; a photochromic layer positioned upstream of the light exit window and downstream of the one or more visible-light sources, said photochromic layer comprising at least one area comprising UV-photochromic material having a first color state and a second color state, wherein the photochromic layer comprises at least two areas comprising different UV-photochromic materials having different recovery times; a control unit connected to the one or more UV-light sources for controlling the one or more UV-light sources, wherein the UV-light sources are arranged to illuminate the photochromic layer; and a first UV-filter arranged downstream of the light exit window.