Reflector and a starting sheet material, for forming a reflector

1. Starting sheet material adapted for forming a reflector for a lighting device, the starting sheet material comprising:

a flat reflective sheet material shaped as a sector of an annulus bendable into a parabolic reflector or a truncated cone reflector, the flat reflective sheet material comprising a first surface, a second surface, a first edge shaped as a segment of a circle with a first radius and a second edge shaped as a segment of a circle with a second radius, the second radius being smaller than the first radius, a third edge and a fourth edge, the third edge and the fourth edge extending between said first edge and said second edge, wherein

optical structures are provided on at least a part of at least one of the first surface and the second surface, said optical structures enabling collimation and/or beam shaping of incident light,

said optical structures being positioned on the flat reflective sheet material along a direction perpendicular to the radial direction of the flat reflective sheet material, and

wherein said positioning of the optical structures establishes gaps between individual optical structures enabling a portion of light emanating from a light source within the reflector and incident to an individual optical structure to be refracted twice by said individual optical structure before being subsequently reflected at the surface of the flat reflective sheet material.

2. Starting sheet material according to claim 1 , wherein said optical structures are applied to the flat reflective sheet material such that a gradient in density of the optical structures in the radial direction of the flat reflective sheet material is provided.

3. Starting sheet material according to claim 1 , wherein said optical structures are provided on a part of the one of the first surface and the second surface of the flat reflective sheet material being closest to said second edge.

4. Starting sheet material according to claim 1 , wherein said optical structures are provided directly on at least a part of the one of the first surface and the second surface.

5. Starting sheet material according to claim 1 , wherein said optical structures are positioned on the first surface and the second surface, or on all of the at least one of the first surface and the second surface, or on all of the first surface and the second surface.

6. Starting sheet material according to claim 1 , wherein said optical structures are based on flexible polymer material.

7. Starting sheet material according to claim 1 , wherein said optical structures are not applied to the flat reflective sheet material by means of employing a prism film.

8. Starting sheet material according to claim 1 , wherein said optical structures are any one of:

refractive optical structures,

diffractive optical structures,

segmented optical structures, and

combinations thereof.

9. Starting sheet material according to claim 1 , wherein said optical structures are provided on the flat reflective sheet material in such a way that the density of the optical structures is any one of:

more than 40%,

more than 60%, and

more than 70%.

10. Starting sheet material according to claim 1 , wherein any one or more of the optical structures, the flat reflective sheet material and the whole starting sheet material is obtained by 3D printing.

11. A reflector for a lighting device, the reflector comprising a starting sheet material according to claim 1 , wherein said starting sheet material is bent in such a way that the one of the first surface and the second surface of the flat reflective sheet material comprising said optical structures form a surface facing towards a center axis of the reflector, and the third edge and the fourth edge of the flat reflective sheet material are brought into contact with one another.

12. A reflector according to claim 11 , wherein the third edge and the fourth edge of the flat reflective sheet material are connected with one another.

13. A reflector according to claim 11 , wherein the reflector is a truncated cone shaped reflector or a parabolic reflector, and/or wherein the reflector is a specular reflector.

14. A lamp, a luminaire, a lighting fixture, a tunable lamp, a tunable luminaire, a tunable lighting fixture, a directional lamp, a directional luminaire or a directional lighting fixture comprising a reflector according to claim 11 .

15. Starting sheet material according to claim 1 , wherein the portion of light that is refracted twice and then reflected at the reflective sheet is greater than 10% of the light incident to an individual optical structure.

16. Starting sheet material according to claim 1 , wherein the portion of light that is refracted twice and then reflected at the reflective sheet is greater than 20% of the light incident to an individual optical structure.

17. Starting sheet material according to claim 1 , wherein the portion of light that is refracted twice and then reflected at the reflective sheet is greater than 35% of the light incident to an individual optical structure.