PDL mitigation structure for diffractive MEMS and gratings

• US 6,922,273 B1
• Filed: 02/28/2003
• Issued: 07/26/2005
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Dueweke, Michael, Maheshwari, Dinesh
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Dinh, Jack
• Application Number:
  US10/377,840
• Time in Patent Office: 879 Days
• Field of Search: 359/290, 359/291, 359/295, 359/298, 359/224, 359/318, 359/572, 359/573, 359/237
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements

Abstract

A modulator for modulating an incident beam of light. The modulator includes a plurality of elements, each element including a first end, a second end, a first non-linear side, a second non-linear side, and a light reflective planar surface. The light reflective planar surfaces of the plurality of elements lie in one or more parallel planes. The elements are preferably arranged parallel to each other. The modulator also includes a support structure to maintain a position of each element relative to each other and to enable movement of selective ones of the plurality of elements in a direction normal to the one or more parallel planes of the plurality of elements. The plurality of elements are preferably moved between a first modulator configuration wherein the plurality of elements act to reflect the incident beam of light as a plane mirror, and a second modulator configuration wherein the plurality of elements act to diffract the incident beam of light. The non-linear sides substantially reduce the polarization dependent losses for diffraction from the plurality of elements.

Claims

1. A modulator for modulating an incident beam of light comprising:

a. a plurality of elements, each element including a first end, a second end, a first non-linear side, a second non-linear side, and a light reflective planar surface with the light reflective planar surfaces of the plurality of elements lying in one or more parallel planes, wherein the elements are arranged parallel to each other; and

b. a support structure coupled to each end of the plurality of elements to maintain a position of each element relative to each other and to enable movement of selective ones of the plurality of elements between a first modulator configuration wherein the plurality of elements act to reflect the incident beam of light as a plane mirror, and a second modulator configuration wherein the plurality of elements act to diffract the incident beam of light.

2. The modulator according to claim 1 wherein the first non-linear side and the second non-linear side each include one or more projections, wherein each projection is perpendicular to the light reflective planar surface.

3. The modulator according to claim 2 wherein a shape of each projection is constant along a thickness of the element.

4. The modulator according to claim 3 wherein the shape of the projection is an arc.

5. The modulator according to claim 3 wherein the shape of the projection is a polygon.

6. The modulator according to claim 3 wherein each projection on the first non-linear side is repeated according to a constant period, and each projection on the second non-linear side is repeated according to a constant period.

7. The modulator according to claim 6 wherein the period of the first non-linear side and the period of the second non-linear side are the same.

8. The modulator according to claim 6 wherein the shape of each projection is the same.

9. The modulator according to claim 8 wherein the projections on the first non-linear side are symmetric in relation to the projections on the second non-linear side.

10. The modulator according to claim 1 wherein the first non-linear side forms a recurring pattern and the second non-linear side forms a recurring pattern.

11. The modulator according to claim 10 wherein the recurring pattern on each side is the same.

12. The modulator according to claim 11 wherein the recurring pattern on the first non-linear side is symmetric in relation to the recurring pattern on the second non-linear side.

13. The modulator according to claim 10 wherein the recurring pattern is formed by alternating halves of a circle.

14. The modulator according to claim 10 wherein the recurring pattern is formed by alternating a sector of a circle and the mirror image of the sector.

15. The modulator according to claim 10 wherein the recurring pattern is a sinusoid.

16. The modulator according to claim 1 wherein the non-linear sides of adjacent elements are separated by a constant gap width.

17. The modulator according to claim 1 wherein the modulator is a diffractive MEMS device.

18. The modulator according to claim 1 wherein the selective ones of the elements are alternating elements and are moved by applying an electrostatic force.

19. A method of modulating an incident beam of light comprising:

a. supporting each of a plurality of elements to maintain a position of each element relative to each other and to enable movement of selective ones of the plurality of elements, wherein each element includes a first end, a second end, a first non-linear side, a second non-linear side, and a light reflective planar surface with the light reflective planar surfaces of the plurality of elements lying in one or more parallel planes, and the elements are arranged parallel to each other; and

b. moving selective ones of the plurality of elements between a first modulator configuration wherein the plurality of elements act to reflect the incident beam of light as a plane mirror, and a second modulator configuration wherein the plurality of elements act to diffract the incident beam of light.

20. A modulator for modulating an incident beam of light comprising:

a. means for supporting each of a plurality of elements to maintain a position of each element relative to each other and to enable movement of selective ones of the plurality of elements, wherein each element includes a first end, a second end, a first non-linear side, a second non-linear side, and a light reflective planar surface with the light reflective planar surfaces of the plurality of elements lying in one or more parallel planes, and the elements are arranged parallel to each other; and

b. means for moving selective ones of the plurality of elements between a first modulator configuration wherein the plurality of elements act to reflect the incident beam of light as a plane mirror, and a second modulator configuration wherein the plurality of elements act to diffract the incident beam of light.