MEMS scanning micromirror

Patent metadata

Field	Value
Publication number	US-9910269-B2
Application number	US-201214361472-A
Country	US
Kind code	B2
Filing date	Nov 28, 2012
Priority date	Nov 29, 2011
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A MEMS-micro-mirror ( 30 ) is provided comprising a mirror body ( 50 ) that is rotatably arranged in a mirror frame ( 60 ) around a rotation axis ( 58 ) extending in a plane defined by the mirror body. The rotation axis extends through a first and a second mutually opposite end-portion ( 51, 53 ) of the mirror body. The mirror has a reflective first main surface ( 55 ) and opposite said first main surface a second main surface ( 57 ) provided with a first and a second pair of reinforcement beams. The pair of reinforcement beams ( 91 a, 91 b ) extends from the first end-portion ( 51 ) in mutually opposite directions away from the rotation axis. The second pair of reinforcement beams ( 93 a, 93 b ) extends from the second end-portion ( 53 ) in mutually opposite directions away from the rotation axis. Reinforcement beams of said first pair extend towards respective ones of said second pair.

First claim

The invention claimed is:

1. A MEMS-micro-mirror comprising a mirror body that is rotatably arranged in a mirror frame around a rotation axis extending in a plane defined by the mirror body, wherein the rotation axis extends through a first and a second mutually opposite end-portion of the mirror body, the mirror body having a reflective first main surface and, opposite said reflective first main surface, a second main surface provided with a first pair of reinforcement beams extending from the first end-portion in mutually opposite directions pointing away from the rotation axis and a second pair of reinforcement beams extending from the second end-portion in mutually opposite directions pointing away from the rotation axis, said first and second pairs of reinforcement beams being formed on said second main surface and rising above said second main surface in a direction away from said reflective first main surface, reinforcement beams of said first pair extending from the first end-portion towards respective ones of said second pair, wherein the reinforcement beams leave free an outer rim of the mirror body, and wherein the reinforcement beams of said first pair have ends pointing away from the rotation axis that are disjunct from those of said second pair.

2. The MEMS-micro-mirror of claim 1 , further comprising additional reinforcement beams formed on said second main surface and rising above said second main surface in a direction away from said reflective first main surface, said additional reinforcement beams extending from an end-portion, each reinforcement beam being arranged between additional reinforcement beams that extend in mutually opposite directions away from said reinforcement beam.

3. The MEMS-micro-mirror of claim 1 , wherein a layer of material forming the reinforcement beams has a direction of lowest material stiffness aligned with the rotation axis.

4. The MEMS-micro-mirror of claim 1 , further comprising a respective reinforcement frame at each end portion, the reinforcement frames interconnecting reinforcement beams of the first pair of beams and of the second pair of beams respectively.

5. The MEMS-micro-mirror of claim 4 , wherein each reinforcement frame is connected to each of its associated reinforcement beams at at least two distinct locations.

6. The MEMS-micro-mirror of claim 1 , wherein the mirror body is rotatably suspended in said mirror frame by a respective coaxial support beam at each end-portion.

7. The MEMS-micro-mirror of claim 1 , constructed of a multi-layer material comprising a first, a second and a third construction layer, the second construction layer being sandwiched between the first and the third construction layer, the mirror body being formed by the first construction layer, and the reinforcement beams being formed in the second and the third construction layer.

8. The MEMS-micro-mirror of claim 7 , wherein the first construction layer has a thickness less than that of the second construction layer.

9. The MEMS-micro-mirror of claim 7 , wherein the second construction layer has a thickness less than that of the third construction layer.

10. The MEMS-micro-mirror of claim 7 , wherein further reinforcement beams are formed on said second main surface, said further reinforcement beams rising above said second main surface in a direction away from said reflective first main surface, said further reinforcement beams branching from or crossing the reinforcement beams from the end-portions, the further reinforcement beams being formed in the second construction layer and the reinforcement beams extending from an end-portion being formed in the second construction layer and the third construction layer.

11. The MEMS-micro-mirror of claim 10 , wherein said further reinforcement beams are oriented at an angle in the range of 45 to 135 degrees with respect to the reinforcement beams from which they branch or which they cross.

12. The MEMS-micro-mirror of claim 1 , being rotatably suspended by a respective coaxial support beam at each end-portion, at least one of the coaxial support beams having a rigid longitudinal portion that mechanically couples the corresponding end-portion to a respective pair of cantilever beams that extend in mutually opposite directions in a direction transverse to the rotation axis towards the mirror frame.

13. The MEMS-micro-mirror of claim 1 , being rotatably suspended by a respective coaxial support beam at each end-portion, at least one of the coaxial support beams having a rigid longitudinal portion that mechanically couples the corresponding end-portion to an actuator.

14. The MEMS-micro-mirror of claim 1 , wherein the reinforcement beams extending from the end-portions have a height that decreases in a direction towards a periphery of the mirror body.

15. The MEMS-micro-mirror of claim 1 , wherein the reinforcement beams extending from the end-portions have a width that decreases in a direction towards a periphery of the mirror body.

16. A method of manufacturing a MEMS-micro-mirror that comprises a mirror body that is rotatably arranged in a mirror frame around a rotation axis extending in a plane defined by the mirror body, wherein the rotation axis extends through a first and a second mutually opposite end-portion of the mirror body, the mirror having a reflective first main surface and opposite said reflective first main surface a second main surface provided with a first pair of reinforcement beams extending from the first end-portion away from the rotation axis, in mutually opposite directions, said first pair of reinforcement beams being formed on said second main surface and rising above said second main surface in a direction away from said reflective first main surface, the method comprising:
providing a Silicon on Insulator product having a first, a second and a third silicon layer as well as a first silicon oxide layer sandwiched between the first and the second silicon layer and a second silicon oxide layer sandwiched between the second and the third silicon layer, wherein the first silicon layer is thinner than the second silicon layer and the second silicon layer is thinner than the third silicon layer;
applying a first patterning process, wherein the first silicon layer is patterned;
applying a second patterning process, wherein the second silicon layer is patterned; and
applying a third patterning process, wherein the third silicon layer is patterned,
wherein the mirror frame is formed in at least the third layer, wherein the mirror body is formed in the first silicon layer, and wherein said reinforcement beams are formed in the second and the third silicon layer, and
wherein the reinforcement beams leave free an outer rim of the mirror body, and
wherein the reinforcement beams of said first pair have ends pointing away from the rotation axis that are disjunct from those of said second pair.

17. A MEMS-micro-mirror comprising a mirror body that is rotatably arranged in a mirror frame around a rotation axis extending in a plane defined by the mirror body, the mirror body comprising:
a first end-portion;
a second end-portion opposite said first end-portion, wherein the rotation axis extends through said first and second end-portions;
a middle portion between said first and second end portions;
a reflective first main surface;
a second main surface opposite said reflective first main surface;
a first pair of reinforcement beams formed on said second main surface, each reinforcement beam of said first pair of reinforcement beams extending from a start point at said first end-portion to an end p

Assignees

• Innoluce B V
• Elmos Semiconductor Ag

Inventors

• Van Lierop Hendrikus Wilhelmus Leonardus Antonius Maria
• Suijlen Matthijs Alexander Gerard

Classifications

• B81B3/007 Primary

  For controlling stiffness, e.g. ribs · CPC title

• B81B2203/0109

  Bridges · CPC title

• G02B26/0841

  the reflecting element being moved or deformed by electrostatic means · CPC title

• B81B2201/042

  Micromirrors, not used as optical switches · CPC title

• B81C1/00666

  Treatments for controlling internal stress or strain in MEMS structures · CPC title