Illumination device and luminaire
Today the use of false ceilings is decreasing as it involves too high an energy consumption. The tendency nowadays is to have bare concrete ceilings onto which luminaires are mounted, which often causes acoustical problems. The invention deals with these acoustical problems and relates to an illumination device ( 1 ) comprising a concave reflector ( 2 ) bordering, with an outer edge ( 3 ), on a light emission window ( 4 ). The reflector has a reflective surface ( 7 ) facing the light emission window. The illumination device further comprises lamp holding means ( 8 ) for accommodating a light source ( 9 ), and said lamp holding means being positioned in between the reflective surface and the light emission window. The illumination device is characterized in that the reflector is made of acoustically absorbing material.
1. An illumination device comprising:
a pair of concave reflectors each made of a single acoustically absorbing and light reflective element and bordering, with an outer edge, on a light emission window, the pair of concave reflectors and the light emission window constituting a boundary of a reflector cavity, the pair of concave reflectors each having a reflective surface facing the light emission window, wherein the acoustically absorbing and reflective element is sufficiently rigid not to deform due to its own weight, wherein the single element of the pair of concave reflectors is configured to both absorb sound and reflect light in the illumination device, and wherein each of the pair of concave reflectors is attached to a top surface of a centrally positioned, elongated bridging element;
a counter reflector made of a single acoustically absorbing and light reflective element and positioned such that a concave reflective surface of the counter reflector faces the reflective surface of each concave reflector, wherein the single element of the counter reflector is configured to both absorb sound and reflect light in the illumination device, wherein the counter reflector is attached to a bottom surface of the bridging element; and
the bridging element configured to accommodate a light source on two opposing sides of the bridging element and being provided at or within the boundary of the reflector cavity in between the counter reflector and the reflective surface of each of the pair of concave reflectors.
2. The illumination device as claimed in claim 1 , wherein each concave reflector is diffusely reflective.
3. The illumination device as claimed in claim 1 , wherein the single acoustically absorbing and reflective element of either the pair of concave reflectors or the counter reflector is a sound absorbing foam.
4. The illumination device as claimed in claim 1 , wherein the single acoustically absorbing and reflective element of the pair of concave reflectors or the counter reflector is flame resistant or heat resistant.
5. The illumination device as claimed in claim 1 , wherein each concave reflector is tapered and comprises an edge wall connecting a narrow end of the pair of concave reflectors of width Woe and a wide end of the pair of concave reflectors of width Wlw, a height H of the pair of concave reflectors being a dimension measured substantially parallel to an axis A of the pair of concave reflectors and transversely to the light emission window, to the light emission window, the relationship between Wlw, Woe, and H being according to the following equation:
tan( a )<=( Wlw+Woe )/2 H,
with a is <=65°.
6. The illumination device as claimed in claim 5 , wherein the edge wall is curved for adapting a beam shape of light emitted by the illumination device.
7. The illumination device as claimed in claim 1 , wherein the light source is at least one side-emitting LED mounted on a printed circuit board for issuing light from the light source in a direction transverse to the axis towards the reflective surface of each concave reflector.
8. A luminaire comprising at least a first illumination device as claimed in claim 7 , wherein the luminaire comprises an acoustically absorbing panel with an optically reflective surface that comprises at least one surface with a plurality of concave surface elements, the first illumination device forming one of said concave surface elements.
9. The luminaire as claimed in claim 8 , wherein the reflective surface of each concave reflector of the first illumination device provides a first beam, and wherein the luminaire comprises integral with the first illumination device at least one further illumination device with at least one further reflector for providing at least one further beam, the further illumination device forming a further one of said concave surface elements.