Light deflector, method of manufacturing light deflector, optical device using light deflector, and torsion oscillating member

• US 20030016428A1
• Filed: 07/05/2002
• Published: 01/23/2003
• Est. Priority Date: 07/11/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kato, Takahisa, Furukawa, Yukio, Shimada, Yasuhiro, Yagi, Takayuki
• Granted Patent: US 6,924,914 B2
• Time in Patent Office: Days
• US Class Current: 359/226
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors
• CPC Class Codes: Y10S 359/90 Methods

Abstract

There is disclosed a light deflector in which both ends of a movable plate is supported to a support substrate by an elastic support portion, a reflection surface is formed on one surface of the movable plate, and the movable plate is torsion-oscillated about a torsion axis of the elastic support portion as a center to deflect an incident light that enters the reflection surface, wherein a recessed portion is formed on at least one side surface of both sides, which is a surface on which the reflection surface is not formed, and between which the torsion axis of the elastic support portion is interposed.

Claims

1. A light deflector in which both ends of a movable plate is supported to a support substrate by an elastic support portion, a reflection surface is formed on one surface of the movable plate, and the movable plate is torsion-oscillated about a torsion axis of the elastic support portion as a center to deflect an incident light that enters the reflection surface, wherein a recessed portion is formed on at least one side surface of both sides, which is a surface on which the reflection surface is not formed, and between which the torsion axis of the elastic support portion is interposed.

2. The light deflector according to claim 1, wherein the recessed portion is formed on at least one surface of both sides, which is a surface of the movable plate opposite to the reflection surface, and between which the torsion axis of the elastic support portion is interposed.

3. The light deflector according to claim 2, wherein a plurality of recessed portions are formed along the torsion axial direction of the elastic support portion.

4. The light deflector according to claim 2, wherein a plurality of recessed portions are formed outwardly from a center of the torsion axis of the elastic support portion, and the plurality of recessed portions are formed so as to gradually outwardly increase at least one of its diameter and its depth.

5. The light deflector according to claim 1, wherein the recessed portion is formed on a side surface of the movable plate.

6. The light deflector according to claim 1, wherein the recessed portion is formed apart from the torsion axis of the movable plate and is not formed in the vicinity of the torsion axis.

7. The light deflector according to claim 1, wherein there is provided a driving means for relatively driving the movable plate with respect to the support substrate.

8. The light deflector according to claim 7, wherein the driving means is an electromagnetic actuator including a fixed core, a coil that is wound around the fixed core and a movable core fixed on one of surfaces between which the torsion axis center of the elastic support portion of the movable plate is interposed.

9. The light deflector according to claim 1, wherein the reflection surface is a reflection diffraction grating.

10. The light deflector according to claim 1, wherein the elastic support portion has an X-shaped cross-section.

11. The light deflector according to claim 1, wherein the support substrate, the elastic support portion, the movable plate and the recessed portion are integrally formed with each other by single crystal silicon.

12. The light deflector according to claim 11, wherein a surface of the movable plate on which the reflection surface is formed is formed of a (100) plane of a silicon crystal face.

13. The light deflector according to claim 11, wherein a recessed portion on a side surface of the movable plate is formed of a (111) plane of a silicon crystal face.

14. The light deflector according to claim 11, wherein a recessed portion on one surface of the movable plate is formed of a (111) plane of a silicon crystal face.

15. The light deflector according to claim 11, wherein the elastic support portion has an X-shaped cross-section which is surrounded by a (100) plane and a (111) plane of a silicon crystal face.

17. The light deflector according to claim 16, wherein the elastic support portion has an X-shaped cross-section.

18. The light deflector according to claim 16, wherein the support substrate, the elastic support portion, the movable plate and the step portion are integrally formed with each other by single crystal silicon.

20. The light deflector according to claim 19, wherein a recessed portion is formed on a side surface of the movable plate.

21. The light deflector according to claim 19, wherein the elastic support portion has an X-shaped cross-section.

22. The light deflector according to claim 19, wherein the support substrate, the elastic support portion, the movable plate and the through-hole are integrally formed with each other by single crystal silicon.

23. An optical device comprising the light deflector according to claim 1.

25. The method according to claim 24, wherein a recessed portion is formed on a side surface of the movable plate at the same time in the anisotropic etching process step.

26. The method according to claim 24, wherein the elastic support portion is formed into an X-shaped cross-section at the same time in the anisotropic etching process step.

30. The torsion oscillating member according to claim 29, wherein the shape of the recessed portion is a step configuration.

31. The torsion oscillating member according to claim 29, wherein the recessed portion is a through-hole.

16. A light deflector in which both ends of a movable plate is supported to a support substrate by an elastic support portion, a reflection surface is formed on one surface of the movable plate, and the movable plate is torsion-oscillated about a torsion axis of the elastic support portion as a center to deflect an incident light that enters the reflection surface, wherein at least one of surfaces, which is a surface of the movable plate opposite to the reflection surface, and between which the torsion axis of the elastic support portion is interposed, is made a step configuration so as to gradually outwardly reduce the thickness of the movable plate.

19. A light deflector in which both ends of a movable plate is supported to a support substrate by an elastic support portion, a reflection surface is formed on one surface of the movable plate, and the movable plate is torsion-oscillated about a torsion axis of the elastic support portion as a center to deflect an incident light that enters the reflection surface, wherein a through-hole is formed on at least one of surfaces between which the torsion axis of the elastic support portion of the movable plate is interposed and in the periphery of the effective reflection region of the movable plate.

24. A method of manufacturing a light deflector, comprising the steps of:

forming mask layers on both surfaces of a silicon substrate;

removing the mask layer on a surface where a reflection surface is formed, with the mask layer corresponding to the outer configuration portions of a support substrate, an elastic support portion and a movable plate being left unremoved;

removing the mask layer on an opposite side to the surface where the reflection surface is formed, with the mask layer corresponding to the outer configuration portions of a support substrate, an elastic support portion and a movable plate being left unremoved, and removing the mask layer on the recessed portion of the movable plate;

emerging the silicon substrate in an alkali aqueous solution and conducting an anisotropic etching process to separate the silicon substrate into the support substrate, the elastic support portion and the movable plate, and forming a recessed portion in one surface of the movable plate;

removing the mask layer on the silicon substrate; and

forming a reflection film on the surface on which the reflection surface of the movable plate is formed.

27. A method of manufacturing a light deflector, comprising the steps of:

forming a mask layer on one surface of a silicon substrate;

forming a reflection film on a portion of the other surface of the silicon substrate on which a reflection surface is formed;

removing the mask layer formed on the silicon substrate portions where a support substrate, an elastic support portion and a movable plate are formed being left unremoved, and etching the regions of the silicon substrate, with the regions the support substrate, the elastic support portion and the movable portion being left unetched, to a given depth through a dry etching process;

repeatedly conducting the removal of the recessed portion of the mask layer formed on the silicon substrate and the etching of the given depth due to the dry etching of the silicon substrate in accordance with the number of recessed portions formed on the movable plate in a direction crossing the torsion axis of the elastic support portion, to thereby separate the silicon substrate into the support substrate, the elastic support portion and the movable plate, and to form on the movable plate a plurality of recessed portions that gradually outwardly increase its diameter and its depth from the torsion axis; and

removing the mask layer of the silicon substrate.

28. A method of manufacturing a light deflector, comprising the steps of:

forming a mask layer on one surface of a silicon substrate;

forming a reflection film on a portion of the other surface of the silicon substrate on which a reflection surface is formed;

removing the mask layer formed on the silicon substrate portions where a support substrate, an elastic support portion and a movable plate are formed being left unremoved, and etching the regions of the silicon substrate, among the regions the support substrate, the elastic support portion and the movable portion being left unetched, to a given depth through a dry etching process;

repeatedly conducting the removal of a flat portion of a step configuration portion of the mask layer formed on the silicon substrate and the etching of the given depth due to the dry etching of the silicon substrate in accordance with the number of step configurations formed on the movable plate, to thereby separate the silicon substrate into the support substrate, the elastic support portion and the movable plate, and to form on the movable plate step portions that gradually outwardly increase its diameter and its depth from the torsion axis; and

removing the mask layer of the silicon substrate.

29. A torsion oscillating member comprising a movable plate, a shaft and a support substrate, in which the movable plate is supported to the support substrate by the shaft connected to both ends of the movable plate, and the movable plate is torsion-oscillatable about the shaft as a center, wherein a recess is formed on at least one region of both sides between which a region on the extension of the shaft is interposed on one face of the movable plate.