Optical pattern generator using multiple reflective surfaces

1. An optical pattern generator for directing an incident optical beam to generate a pattern of figures, the optical pattern generator comprising:

a support structure that rotates around a rotational axis, the rotational axis defining a plane of rotation that is perpendicular to the rotational axis;

a plurality of pairs of reflective surfaces supported by the support structure and rotating with the support structure around the rotational axis, all reflective surfaces positioned approximately in the plane of rotation at a same distance from the rotational axis, the reflective surfaces in each pair positioned approximately on opposite sides of the rotational axis and approximately facing each other;

wherein for each pair of reflective surfaces, as one of the reflective surfaces in the pair rotates through the incident optical beam, the incident optical beam reflects off said reflective surface to the other reflective surface, and reflects off the other reflective surface to exit as an output optical beam, the output optical beam propagating in a direction that is substantially invariant as the pair of reflective surfaces rotates through the incident optical beam;

wherein normals for each of the reflective surfaces are substantially collinear with the incident optical beam as the incident optical beam reflects off of each reflective surface;

wherein, for all pairs of reflective surfaces, the direction of propagation of the incident optical beam and the direction of propagation of the exit optical beam differ by less than 20 degrees; and

wherein the incident optical beam and the exit optical beam are substantially collinear.

2. The optical pattern generator of claim 1 wherein, for all pairs of reflective surfaces, the direction of propagation of the incident optical beam and the direction of propagation of the exit optical beam differ by less than 10 degrees.

3. The optical pattern generator of claim 1 wherein, for all pairs of reflective surfaces, the direction of propagation of the incident optical beam and the direction of propagation of the exit optical beam lie primarily in a plane that is substantially perpendicular to the rotational axis.

4. The optical pattern generator of claim 1 wherein the reflective surfaces of one pair have a different tilt angle than the reflective surfaces of a different pair, the tilt angle of a reflective surface defined as the angle between the plane of rotation and a surface normal of the reflective surface.

5. The optical pattern generator of claim 1 wherein the reflective surfaces of each pair have a different tilt angle than the reflective surfaces of every other pair, the tilt angle of a reflective surface defined as the angle between the plane of rotation and a surface normal of the reflective surface.

6. The optical pattern generator of claim 1 wherein, for each pair of reflective surfaces, both reflective surfaces have a same tilt angle, the tilt angle of a reflective surface defined as the angle between the plane of rotation and a surface normal of the reflective surface.

7. The optical pattern generator of claim 1 wherein all reflective surfaces are tilted outward.

8. The optical pattern generator of claim 1 wherein the reflective surfaces of one pair have a different twist angle than the reflective surfaces of a different pair, the twist angle of a reflective surface defined as the angle between a radial direction for the rotational axis and a projection of a surface normal of the reflective surface onto the plane of rotation.

9. The optical pattern generator of claim 1 wherein the reflective surfaces of each pair have a different twist angle than the reflective surfaces of every other pair, the twist angle of a reflective surface defined as the angle between a radial direction for the rotational axis and a projection of a surface normal of the reflective surface onto the plane of rotation.

10. The optical pattern generator of claim 1 wherein the reflective surfaces of one pair have a different width than the reflective surfaces of a different pair.

11. The optical pattern generator of claim 10 wherein the reflective surfaces of each pair have a different width than the reflective surfaces of every other pair.

12. The optical pattern generator of claim 1 wherein at least one reflective surface is not flat.

13. The optical pattern generator of claim 1 wherein all reflective surface surfaces are flat.

14. The optical pattern generator of claim 1 wherein each pair of reflective surfaces rotates through the incident optical beam in 1 ms or less.

15. The optical pattern generator of claim 1 wherein the plurality of pairs of reflective surfaces includes at least five pairs of reflective surfaces.

16. The optical pattern generator of claim 1 wherein the reflective surfaces are mirrors.

17. The optical pattern generator of claim 1 wherein the reflective surfaces are non-reflective structures covered by a reflective coating.

18. The optical pattern generator of claim 1 wherein the support structure is a disk and the reflective surfaces are mounted to the disk.

19. The optical pattern generator of claim 1 wherein the support structure and reflective surfaces comprise a monolithic structure, the monolithic structure including the reflective surfaces.

20. The optical pattern generator of claim 1 wherein the support structure and reflective surfaces comprise a monolithic structure with non-reflective surfaces covered by a reflective coating.

21. The optical pattern generator of claim 20 wherein the monolithic structure is formed by injection molding, electroforming or epoxy-replication.

22. The optical pattern generator of claim 18 , wherein the disk has an outer peripheral edge, and the reflective surfaces are mounted to the outer peripheral edge of the disk.