Oscillating structure with reduced dynamic deformation, optical device including the oscillating structure, and method of manufacturing the oscillating structure

Patent metadata

Field	Value
Publication number	US-10914938-B2
Application number	US-201815955107-A
Country	US
Kind code	B2
Filing date	Apr 17, 2018
Priority date	Apr 20, 2017
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

An oscillating structure includes first and second torsional elastic elements that define an axis of rotation and a moving element that is interposed between the first and second torsional elastic elements. The moving element, the first torsional elastic element and the second torsional elastic element lie in a first plane and are not in direct contact with one another. A coupling structure mechanically couples the moving element, the first torsional elastic element and the second torsional elastic element together. The moving element, the first torsional elastic element and the second torsional elastic element lie in a second plane different from the first plane. Oscillation of the moving element occurs as a result of a twisting of the first and second torsional elastic elements.

First claim

The invention claimed is:

1. An oscillating structure, comprising:
first and second torsional elastic elements defining an axis of rotation,
a moving element interposed between said first and second torsional elastic elements, the moving element being configured to rotate about the axis of rotation as a result of a twisting of the first and second torsional elastic elements,
wherein the moving element, the first torsional elastic element and the second torsional elastic element lie on a first plane and are separated from one another,
a coupling structure lying in a second plane different from said first plane, wherein said moving element, said first torsional elastic element and said second torsional elastic element are mechanically coupled together by the coupling structure, and
first, second, and third physical layer structures lying in a third plane between the first and second planes and spaced apart from one another by free space, the first physical layer structure linking the coupling structure with the moving element, the second physical layer structure linking the coupling structure with the first torsional elastic element, and the third physical layer structure linking the coupling structure with the second torsional elastic element.

2. The oscillating structure according to claim 1 , wherein said moving element, said first torsional elastic element and said second torsional elastic element are mechanically coupled together exclusively through the coupling structure.

3. The oscillating structure according to claim 1 , wherein the second plane of the coupling structure is parallel to the first plane and extends at a height lower than the first plane.

4. The oscillating structure according to claim 1 , wherein the coupling structure includes an annular portion that contains one or more through-hole apertures.

5. The oscillating structure according to claim 1 , wherein said second and third physical layer structures extend along the axis of rotation, and wherein said first physical layer structure extends along a respective axis orthogonal to the axis of rotation.

6. The oscillating structure according to claim 1 , wherein said first, second, and third physical layer structures are arranged such as to maximize distance between each other.

7. The oscillating structure according to claim 1 , wherein the coupling structure includes an elliptical annular portion, said first, second, and third physical layer structures being arranged at vertices of a cross formed by a minor axis and a major axis of an ellipse describing the elliptical annular portion.

8. The oscillating structure according to claim 1 , wherein the coupling structure includes a quadrangular annular portion with beveled corners, said first, second, and third physical layer structures including midpoints of large and small sides of a quadrangle describing said quadrangular annular portion.

9. The oscillating structure according to claim 1 , wherein perimeter regions of the coupling structure, at the first physical layer structure, is arranged above the moving element.

10. The oscillating structure according to claim 1 , wherein outer edges of the coupling structure, at the first physical layer structure, coincide, at at least one point, with respective outer edges of a central portion.

11. The oscillating structure according to claim 1 , wherein the coupling structure also includes a support portion lying in the second plane.

12. The oscillating structure according to claim 1 , wherein the moving element contains a reflective element, said oscillating structure forming a micro-mirror.

13. An optical device, including the micro-mirror according to claim 12 .

14. The optical device according to claim 13 , further including:
a light source configured to generate a light beam that is incident on said reflective element, and
an image generation module operatively coupled to said oscillating structure to generate part of an image associated with a light beam reflected by said reflective element.

15. A method of manufacturing an oscillating structure, comprising the steps of:
forming first and second torsional elastic elements defining an axis of rotation, and
forming a moving element positioned between said first and second torsional elastic elements, the moving element being configured to rotate about an axis of rotation as a result of a twisting of the first and second torsional elastic elements,
wherein the moving element, the first torsional elastic element and the second torsional elastic element lie on a first plane,
wherein the first torsional elastic element, the second torsional elastic element and the moving element are arranged at a distance from one another,
forming a coupling structure in a second plane other than said first plane, and
forming first, second, and third physical layer structures lying in a third plane between the first and second planes and spaced apart from one another by free space, the first physical layer structure linking the coupling structure with the moving element, the second physical layer structure linking the coupling structure with the first torsional elastic element, and the third physical layer structure linking the coupling structure with the second torsional elastic element.

16. The method according to claim 15 , wherein the step of forming the coupling structure includes the step of forming an annular portion that contains one or more through-hole apertures.

17. The method according to claim 15 , further including the step of matching, at at least one point of the first physical layer structure, outer edges of the coupling structure with respective outer edges of a central portion.

18. The method according to claim 15 , wherein the steps of forming the first torsional elastic element, the second torsional elastic element, the moving element and the first, second, and third physical layer structures include processing a silicon-over-insulator (SOI) wafer.

Assignees

• St Microelectronics Srl

Inventors

• Carminati Roberto
• Costantini Sonia
• Carminati Marta

Classifications

• G02B26/08 Primary

  for controlling the direction of light (in light guides G02B6/35) · CPC title

• G02B26/10

  Scanning systems · CPC title

• G02B26/0816

  by means of one or more reflecting elements · CPC title

• B81B2201/042

  Micromirrors, not used as optical switches · CPC title

• G02B26/105

  with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence) · CPC title