MICROMECHANICAL FLEXURE DESIGN USING SIDEWALL BEAM FABRICATION TECHNOLOGY
This disclosure provides systems, methods and apparatus utilizing flexures in a display. In some implementations, an electromechanical systems (EMS) device can include flexures that have low stiffness along the axis of motion of a light modulator, and high stiffness in other directions. The flexures may include one or more beams mechanically coupling a MEMS structure to an anchor. The beams may be coupled to a hinge portion, the hinge portion being configured to suppress out of plane motion by the MEMS structure and the flexures. The flexures also may suppress out-of-plane motion using a stiffened portion. The stiffened portion can be mechanically coupled to the hinge portion or at least one beam of the flexure. By varying the cross-section geometry of the stiffened portion, the stiffness of the stiffened portion may be controlled to increase the force required to move the flexure in an out-of-plane direction.
1 . An electromechanical device, comprising:
a microelectromechanical systems (MEMS) flexure 400 having a first beam 412 , and a second beam 418 positioned substantially parallel the first beam 412 , the first beam 412 and second beam 418 extending in a first direction, and a hinge 402 located at a first end of the first beam 412 and coupling the first beam 412 to the second beam 418 , the hinge 402 having:
a first hinge beam 414 extending in a second direction and transverse to the first and second beams; and
a stiffened portion 404 coupled to the first hinge beam 412 in a first location, the stiffened portion 404 including a two-dimensional surface extending in a plane substantially parallel to a first plane.
2 . The electromechanical device of claim 1 , wherein a cross-section of the stiffened portion is variable.
3 . The electromechanical device of claim 2 , wherein the stiffened portion is recessed in the z-direction.
4 . The electromechanical device of claim 1 , wherein a mass of the stiffened portion is varied through the z-direction.
5 . The electromechanical device of claim 1 , wherein the first beam is coupled to an anchor and wherein the anchor is attached to a substrate.
6 . The electromechanical device of claim 1 , wherein the second beam is coupled to a light modulator.
7 . The electromechanical device of claim 1 , wherein the hinge further includes a four-segment portion coupled to the stiffened portion.
8 . The electromechanical device of claim 1 , further comprising a second hinge coupling the second beam to a third beam.
9 . The electromechanical device of claim 1 , wherein the first direction corresponds to an x-direction, the second direction corresponds to a y-direction and the first plane corresponds to an xy-plane.
10 . An electromechanical device, comprising:
an anchor 702 coupled to a substrate;
a first beam 706 extending in a first direction and coupled to the anchor 702 ;
a second beam 710 extending in a second direction and coupled to the first beam 706 ; and
a third beam 726 extending in the first direction and coupled between the second beam 710 and a light modulator 716 , wherein at least one of the first beam 706 , the second beam 710 and the third beam 726 is coupled to a stiffened portion 724 .
11 . The electromechanical device of claim 10 , wherein a cross-section of the stiffened portion is variable.
12 . The electromechanical device of claim 11 , wherein the stiffened portion is recessed in the z-direction.
13 . The electromechanical device of claim 12 , wherein a mass of the stiffened portion is varied through the z-direction.
14 . The electromechanical device of claim 10 , wherein the stiffened portion is coupled to the anchor.
15 . The electromechanical device of claim 10 , wherein the stiffened portion is coupled to the light modulator.
16 . The electromechanical device of claim 10 , wherein the light modulator moves in the first direction and substantially parallel to the substrate.
17 . An electromechanical device, comprising:
an anchor means coupled to a substrate means;
a first beam means extending in a first direction and coupled to the anchor means;
a second beam means extending in a second direction and coupled to the first beam means; and
a third beam means extending in the first direction and coupled between the second beam means and a light modulator means, wherein at least one of the first beam means, the second beam means and the third beam means is coupled to a stiffened means.
18 . The electromechanical device of claim 17 , wherein a cross-section of the stiffened means is variable.
19 . The electromechanical device of claim 18 , wherein the stiffened means is recessed in the z-direction.
20 . The electromechanical device of claim 19 , wherein a mass of the stiffened means is varied through the z-direction.