Optical scanning using vibratory diffraction gratings

• US 7,542,188 B2
• Filed: 12/23/2004
• Issued: 06/02/2009
• Est. Priority Date: 01/20/2004
• Status: Expired due to Fees

• Current Assignee: National University of Singapore
• Original Assignee: National University of Singapore
• Inventors: Zhou, Guangya, Vj, Logeeswaran, Chau, Fook Siong
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US11/019,519
• Publication Number:
  US 20050156481A1
• Time in Patent Office: 1,622 Days
• Field of Search: 310/309, 359/569, 359/573, 359197-199, 359223-226, 348203-205
• US Class Current: 359/199.1
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/056 Rotation in a plane parallel to the substrate
• CPC Class Codes: B81B 3/0062 Devices moving in two or more dimensions, i.e. having special features which allow movement in more than one dimension
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 26/106 having diffraction gratings as scanning elements, e.g. holographic scanners holographic optical elements G02B5/32, holography G03H
• CPC Class Codes: H02N 1/008 Laterally driven motors, e.g. of the comb-drive type

Abstract

An optical scanning apparatus includes an in-plane vibratory mass platform having at least one diffraction grating formed thereon as the scanning element, at least one flexure structure that connects the mass platform to at least one fixed support, and at least one driving actuator that drives the mass platform into an in-plane vibratory motion which can be rotational and/or translational. The apparatus may also be formed by a mass platform having at least one diffraction grating formed thereon as the scanning element, at least one driving actuator connected to the mass platform through at least one flexure structure. The driving actuator drives the mass platform into an in-plane vibratory motion.

Claims

1. An optical scanning system, comprising:

a mass platform;

at least one support structure connected to the mass platform though at least one flexural structure;

at least one diffraction grating patterned on the mass platform; and

at least one driving actuator, which drives the mass platform to vary the orientation of the grating lines through an in-plane oscillatory rotational motion of the mass platform, about a center of rotation which is fixed or variable,

wherein said in-plane oscillatory rotational motion is combined with out-of-plane motion, that is less than 100 Hz, and that is at least one of rotational or translational motion.

2. An optical scanning system, comprising:

mass platform;

at least one support structure connected to the mass platform through at least one flexural structure;

at least one diffraction grating patterned on the mass platform; and

at least one driving actuator, which drives the mass platform to vary the orientation of the grating lines through an in-plane oscillatory rotational motion of the mass platform, about a center of rotation which is fixed or variable,

wherein the flexural structure is a first flexural structure connected to the mass platform, and the first flexural structure transversely connects to a second flexural structure, and the second flexural structure is connected to the support structure.

3. The optical scanning system of claim 2,

wherein said in-plane oscillatory rotational motion is combined with out-of-plane motion, that is less than 100 Hz, and that is at least one of rotational or translational motion.

4. The optical scanning system of claim 2,

wherein the in-plane oscillatory rotational motion is combined with out-of-plane motion, that is less than 100 Hz, and that is at least one of rotational or translational motion, and the structure is used for multi-dimensional scanning.

5. The optical scanning system of claim 2, wherein the mass platform, the flexure structure and driving actuator either is or is not formed on the same substrate and their center-of-mass are not confined to lie on the same plane.

6. The optical scanning system of claim 2, wherein the diffraction grating is orientated at an angle with respect to the mass platform, wherein the angle is any angle between 0°

and 180°

.

7. The optical scanning system of claim 2, wherein an excitation force produced by the at least one driving actuator is applied directly to the mass platform.

8. The optical scanning system of claim 2, wherein an excitation force produced by the at least one driving actuator is applied directly to the flexural structure.

9. The optical scanning system of claim 2, wherein an excitation force produced by the at least one driving actuator is applied directly to the support structure.

10. The optical scanning system of claim 2, wherein the support structure can be fixed or movable.

11. The optical scanning system of claim 2, wherein the mass platform and the flexure structure has a geometrical shape or topology, wherein the geometrical shape or topology is symmetrical or non-symmetrical.

12. The optical scanning system of claim 2, wherein the driving actuator comprises a comb drive having an interdigitated finger structure having fixed fingers and movable fingers.

13. The optical scanning system of claim 12, wherein the movable fingers connect to the mass platform.

14. The optical scanning system of claim 12, wherein the fixed fingers comprise a fixed electrode connected to a substrate.

15. The optical scanning system of claim 12, wherein the comb drive is a circular comb drive.

16. The optical scanning system of claim 2, further comprising a folded beam suspension connected to the support structure.

17. The optical scanning system of claim 16, wherein the folded beam suspension is connected to a substrate.

18. The optical scanning system of claim 2, wherein the center of rotation is fixed at the geometric center of the mass platform.

19. The optical scanning system of claim 2, wherein the frequency of the in-plane rotation is 10 kHz or greater.

20. The optical scanning system of claim 2, wherein the center of rotation is fixed.

21. The optical scanning system of claim 2, wherein the center of rotation is variable.

22. The optical scanning system of claim 2, wherein the at least one diffraction grating is attached directly on the mass platform.

23. The optical scanning system of claim 2, wherein an angle of incidence of a light beam incident on the at least one diffraction grating with respect to its normal remains constant when the mass platform is moved exclusively in the in-plane oscillatory rotational motion.