Illumination system
The illumination system has an array of light sources ( 1, 1 ′, . . . ) such as an array of light emitting diodes arranged in a pre-determined manner in a first plane ( 11 ), wherein d source is a characteristic dimension of the spatial arrangement of the light sources in the first plane. An array of associated lenses ( 2, 2 ′, . . . ) is arranged in substantially the same pre-determined manner in a second plane ( 12 ). Each lens has substantially the same focal distance f lens . The array of lenses is provided at a plane distance d plane from the array of light sources. The plane distance d plane is substantially equal to the focal distance f lens of the lenses. The illumination system has displacement means for displacing the array of lenses with respect to the array of light sources so as to obtain a plurality of directional light beams projecting spots on a projection plane arranged at a projection distance d projection from the illumination system, wherein d projection ≧10×d source and d projection ≧10×d plane .
1. An illumination system comprising:
an array of light sources arranged in a pre-determined manner in a first plane wherein d source is a characteristic dimension of the spatial arrangement of the light sources in the first plane representing the distance between adjacent light sources,
an array of associated lenses arranged in substantially the same pre-determined manner in a second plane, each lens having substantially the same focal distance f lens and having a distance between a centerpoint of each of said associated lenses of d lens , said array of light sources and said array of lenses rotatably mounted relative to each other;
the second plane being arranged substantially parallel to the first plane,
the array of lenses being provided at a plane distance d plane from the array of light sources, the plane distance d plane being substantially equal to the focal distance f lens of the lenses,
said rotatable mounting of said plurality of lenses and said plurality of light sources relative to each other sufficient for displacing the array of lenses with respect to the array of light sources parallel to the first plane so as to obtain a plurality of directional light beams projecting spots on a projection plane arranged at a projection distance d projection from the illumination system, wherein d projection ≧10×d source and d projection ≧10×d plane , wherein d lens <d source , wherein d lens is a characteristic dimension of the spatial arrangement of the lenses;
wherein said dimension d lens <d source , causes said plurality of directed light beams to overlap to form a single spot when said array of lenses are in a first rotational position relative to said array of light sources;
a rotatable mount positioning said array of lenses and said array of light sources in a second rotational position repositioning said single spot without tilting said illumination system and maintaining substantially the same distance of said d plane ;
said rotatable mount positioning said array of lenses and said array of light sources in a third rotational position creating a broadened spot relative to said single spot wherein said plurality of directional beams overlap.
2. The illumination system as claimed in claim 1 , wherein the ratio of the characteristic dimension of the spatial arrangement of the light sources in the first plane and the characteristic dimension of the spatial arrangement of the lenses in the second plane meets the relation:
d
source
=
d
lens
×
(
1
+
d
plane
d
projection
)
.
3. The illumination system as claimed in claim 2 , wherein the light sources and the lenses are arranged in a hexagonal structure.
4. The illumination system as claimed in claim 1 , wherein said rotatable mount of said array of lenses relative to said array of light sources is constructed for translational displacement of the array of lenses so as to obtain a joint translational displacement of the spots.
5. The illumination system as claimed in claim 4 , wherein
the translational displacement comprises a position in which a lens optical axis of at least one of the lenses coincides with a source optical axis of at least one of the light sources so as to obtain substantially coinciding spots on the projection plane,
the translational displacement of the array of lenses causing a corresponding displacement of the coinciding spots, and
the lens optical axis and the source optical axis being perpendicular to the second and the first plane, respectively.
6. The illumination system as claimed in claim 1 , wherein said rotatable mount is constructed for rotational displacement of the array of lenses so as to obtain a rotational displacement of the spots, the angles of the light beams with respect to an axis perpendicular to the second plane changing upon rotation.
7. The illumination system as claimed in claim 1 , wherein the array of lenses comprises an array of Fresnel lenses.
8. The illumination system as claimed in claim 1 , wherein the array of light sources comprises an array of light-emitting diodes.
9. The illumination system as claimed in claim 8 , wherein the array of light-emitting diodes comprises a plurality of light-emitting diodes of different primary colors.
10. The illumination system as claimed in claim 1 , wherein the array of light sources comprises an array of light-outcoupling structures arranged in a light guide, the light guide being provided with at least one primary source of light.
11. An illumination system comprising:
a plurality of light sources arranged in a first plane and a plurality of associated lenses arranged in a second plane, said first plane and said second plane substantially parallel, said plurality of light sources rotatably mounted relative to said plurality of lenses while maintaining substantially the same distance between said light sources and said lenses;
wherein said plurality of light sources are in a spatial arrangement d source in said first plane representing the distance between adjacent light sources,
the plurality of lenses being positioned on said plane a distance d plane from said plurality of light sources,
wherein said plane distance d plane substantially equal to a focal distance f lens of said plurality of lenses and wherein d lens is a dimension of the spatial separation arrangement of said plurality of lenses and the centerpoint of each of said plurality of lenses;
said rotatable mounting of said lenses and said light sources relative to each other sufficient for displacing the array of lenses with respect to the array of light sources parallel to the first plane so as to obtain a plurality of directional light beams projecting spots on a projection plane arranged at a projection distance d projection from said second plane, wherein d projection ≧10×d source and d projection ≧10×d plane , wherein d lens <d source ,
wherein said d lens <d source , causes said plurality of directed light beams to overlap to form a single spot when said array of lenses are in a first rotational position relative to said array of light sources;
said rotatable mount positioning said array of lenses and said array of light sources in a second rotational position repositioning said single spot without tilting said illumination system;
said rotatable mount positioning said array of lenses and said array of light sources in a third rotational position creating a broadened spot relative to said single spot wherein said plurality of directional beams overlap.