Collimator device, a lighting device, a lamp and a luminaire
The invention provides a collimator device for a lighting application which comprises a collimator panel having a first end face which receives input light and a second end face which provides collimated light. The second end face is opposite to the first end face. The collimator panel comprises a plurality of walls which extend between the first end face and the second end face to obtain a grid of cells. The cells extend between the first end face and the second end face to obtain the collimated light. At least the plurality of the walls are arranged to obtain cross-sections of the associated cells which form an auxetic structure. The collimator panel is deformable from a first structure into a second structure by changing the cross-section of the associated cells to change the collimated light from a first spatial distribution into collimated light having a second spatial distribution. The first spatial distribution is different from the second spatial distribution.
1. A lighting device comprising a light source for providing light source light and a collimator device, and being arranged in the optical path of the light source light; the collimator device comprising:
a collimator panel having a first end face for receiving input light and a second end face for providing collimated light, wherein the second end face is opposite to the first end face,
the collimator panel comprising a plurality of walls extending between the first end face and the second end face for obtaining a grid of cells, the cells extending between the first end face and the second end face for obtaining the collimated light, at least the plurality of the walls being arranged for obtaining cross-sections of the associated cells forming an auxetic structure, and
wherein the collimator panel is deformable from a first structure into a second structure and back by changing the cross-sections of the associated cells to change the collimated light having a first spatial distribution into collimated light having a second spatial distribution, wherein the first spatial distribution is different from the second spatial distribution.
2. The lighting device according to claim 1 , wherein the plurality of walls are light absorbing, light reflecting or light diffusing.
3. The lighting device according to claim 1 , wherein the plurality of walls are arranged at an angle in the range from 60 to 120 degrees to the first end face.
4. The lighting device according to claim 1 , wherein the plurality of walls are arranged perpendicular to the first end face.
5. The lighting device according to claim 1 , wherein the auxetic structure having a Poisson ratio in the range from −0.5 to −1.5.
6. The lighting device according to claim 1 , wherein the auxetic structure having a Poisson ratio in the range from −0.8 to −1.1.
7. The lighting device according to claim 1 , wherein the auxetic structure is bistable.
8. The lighting device according to claim 1 , wherein the auxetic structure is at least ten times deformable from the first structure to the second structure.
9. The lighting device according to claim 1 , wherein the cells of the auxetic structure have one or more of the following shapes: auxetic hexagonal shape, auxetic square shape, auxetic rectangular shape, and auxetic triangular shape.
10. The lighting device according to claim 1 , wherein the auxetic structure comprising at least a first wall of the plurality of the walls being light diffusing and at least a second wall of the plurality of the walls being light absorbing.
11. The lighting device according to claim 1 , further comprising attachment means arranged for attaching the collimator device to an object.
12. The lighting device according to claim 1 , comprising at least the collimator panel and a further collimator panel.
13. The lighting device according to claim 1 , comprising an optical element selected from the group of a reflector, a lens, a lens array and/or a total internal reflection optical element and being arranged between the light source and the collimator device.
14. A luminaire or lamp comprising the lighting device as claimed in claim 1 .