US-20260125261-A1 - MEMS ELECTROSTATIC ACTUATOR BLADE CONFIGURATIONS AND METHODS OF MANUFACTURE

US20260125261A1US 20260125261 A1US20260125261 A1US 20260125261A1US-20260125261-A1

Abstract

Methods, apparatuses and methods of manufacture are described for a MEMS electrostatic blade actuator with different configurations to allow for improvements to performance. The MEMS electrostatic blade actuator with different configurations can be used in a MEMS mirror to reduce mass or reduce operating voltage.

Inventors

Andrew Hocking
Scott A. Miller

Assignees

CALIENT.AI INC.

Dates

Publication Date: 20260507
Application Date: 20251029

Claims (20)

1 . An actuator, comprising: a frame defining a cavity, the frame including a first base; a stage including a second base; a first flexure and a second flexure suspending the stage within the cavity; a first blade coupled to the first base; a second blade coupled to the second base; and an insulation layer comprising a first portion disposed between the first base and the first blade, a second portion disposed between the second base and the second blade, and a third portion disposed on the second blade, wherein the third portion of the insulation layer has a first side in contact with the second blade and a second side that is exposed.
2 . The actuator of claim 1 , wherein the insulation layer comprises a buried oxide layer.
3 . The actuator of claim 1 , wherein the first blade is electrically connected to the first base by at least one first via extending through the first portion of the insulation layer.
4 . The actuator of claim 1 , wherein the second blade is electrically connected to the second base by at least one first via extending through the second portion of the insulation layer.
5 . The actuator of claim 1 , wherein the first blade extends from the first base substantially perpendicularly so that the first base and the first blade define a T-shaped configuration.
6 . The actuator of claim 1 , wherein the third portion of the insulation layer and a side surface of the second base collectively define a notch.
7 . The actuator of claim 6 , wherein the notch defines an opening that overlaps at least partially with the first base in a first direction.
8 . The actuator of claim 1 , wherein applying different voltages to the first blade and the second blade causes the second blade to be electrostatically attracted toward the first blade, thereby causing the stage to pivot about the first and second flexures.
9 . The actuator of claim 1 , wherein: applying different voltages to the first blade and the second blade causes the second blade to overlap with the first blade, thereby generating a primary actuating torque; applying the different voltages to the first blade and the second blade further causes the second blade to also overlap with a first end of the first base, thereby generating a supplemental actuating torque; and the first blade extends from the first base substantially perpendicularly such that the first base and the first blade define a T-shaped configuration.
10 . The actuator of claim 1 , further comprising a third blade coupled to a third base; wherein: applying a first voltage to the first blade and the third blade and applying a second voltage to the second blade cause the second blade to overlap with the first blade and the third blade, thereby generating a primary actuating torque; applying the first voltage to the first blade and the third blade and applying the second voltage to the second blade further cause the second blade to also overlap with a first end of the first base and a first end of third base thereby generating a supplemental actuating torque; the first blade extends from the first base substantially perpendicularly such that the first base and the first blade define a first T-shaped configuration; the third blade extends from the third base substantially perpendicularly such that the third base and the third blade define a second T-shaped configuration, the frame includes the third base; and the first voltage is different from the second voltage.
11 . An actuator, comprising: a frame defining a cavity; a stage; a first flexure and a second flexure suspending the stage within the cavity; a plurality of stage fingers extended from the stage toward the frame, the stage fingers including a first stage finger; and a plurality of frame fingers extended from the frame toward the stage, the frame fingers including a first frame finger, wherein an end portion of the first stage finger overlaps with an end portion of the first frame finger.
12 . The actuator of claim 11 , further comprising: a first blade extending from the stage; and a second blade extending from the frame, the first and second blades being substantially parallel.
13 . The actuator of claim 11 , further comprising: a first blade extending from the stage; a second blade extending from the frame; and a third blade extending form the frame, the second and third blades being spaced apart to define a gap, wherein the first blade is configured to tilt into the gap during operation.
14 . The actuator of claim 11 , wherein: the plurality of stage fingers includes the first stage finger and a second stage finger in parallel with the first stage finger; and the end portion of the first frame finger is disposed between the first stage finger and the second stage finger.
15 . The actuator of claim 11 , wherein: the plurality of frame fingers includes the first frame finger and a second frame finger in parallel with the first frame finger; and the end portion of the first stage finger is disposed between the first frame finger and the second frame finger.
16 . The actuator of claim 12 , wherein applying different voltages to the first blade and the second blade causes the plurality of stage fingers to be electrostatically attracted toward the plurality of frame fingers, thereby causing the stage to pivot about the first and second flexures.
17 . The actuator of claim 12 , wherein applying different voltages to the first blade and the second blade, the plurality of stage fingers and the plurality of frame fingers generate a first actuating torque; and applying the different voltages to the first blade and the second blade further causes the first blade to overlap with the second blade, thereby generating a second actuating torque.
18 . The actuator of claim 12 , wherein applying different voltages to the first blade and the second blade, the plurality of stage fingers and the plurality of frame fingers generate a first actuating torque; applying the different voltages to the first blade and the second blade further causes the first blade to overlap with the second blade, thereby generating a second actuating torque; and applying the different voltages to the first blade and the second blade further causes the first blade to overlap with the plurality of frame fingers, thereby generating a third actuating torque.
19 . The actuator of claim 12 , wherein: a first overlap area is defined by interleaving of the plurality of stage fingers with the plurality of frame fingers; and applying different voltages to the first blade and the second blade causes the first overlap area increases.
20 . The actuator of claim 12 , wherein: a first overlap area is defined by a first overlapping area of the first blade and the second blade; and applying different voltages to the first blade and the second blade causes the first overlap area increases.

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims priority to U.S. Provisional Application No. 63/714,979, filed on Nov. 1, 2024. The entire contents of the above-identified application are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to the field of electrostatic blade actuators and, more particularly, to various actuator configurations developed to enhance device performance. BACKGROUND Microelectromechanical systems (MEMS) and their arrays may incorporate parallel-plate actuators designed with gaps significantly larger than the actuator's stroke range. When a voltage is applied across the electrode plates, an attractive electrostatic force is generated, causing one plate to rotate. The maximum achievable rotation depends on the separation between the opposing plates. A larger gap allows greater deflection; however, in practice, the gap is usually made larger than strictly required for the plate's physical motion. This is because when the distance between the plates becomes too small (e.g., less than about one-third of the initial gap), the system reaches an unstable point at which the electrodes may suddenly snap together. The force generated by a parallel-plate actuator is proportional to (voltage/gap)2. Consequently, as the electrode gap increases, the required voltage rises with the square of the distance in order to produce the same force. During operation, the electrode plates do not remain perfectly parallel, causing the effective gap to decrease as the structure moves. As a result, the voltage required to achieve a specific displacement is high, nonlinear, and continuously varying. Furthermore, employing a large gap can introduce crosstalk between neighboring actuators within an array. U.S. Pat. No. 6,753,638 (Adams), entitled “Electrostatic Actuator for Micromechanical Systems,” describes an electrostatic blade actuator designed to address the limitations of conventional parallel-plate actuators. In the apparatus disclosed, a stage includes a surface with a first blade extending perpendicularly from that surface. A frame likewise includes a surface with a second blade extending perpendicularly, positioned parallel to the first blade. The stage is pivotally coupled to the frame, enabling interaction between the blades to achieve actuation. FIGS. 1A and 1B illustrate a blade actuator 100 described in U.S. Pat. No. 6,753,638. Blade actuator 100 includes a stage 140 and a frame 135. FIG. 1A shows stage 140 parallel to frame 135. FIG. 1B shows stage 140 tilted with respect to frame 135. Stage 140 may have a reflective element 145, such as a mirror, disposed on the top surface of stage 140. Stage 140 is pivotally coupled to frame 135 using stage flexures 153, 154 on diametrically opposed sides of stage 140. Stage flexures 153, 154 suspend stage 140 in a cavity formed by frame 135 such that stage 140 is free to pivot around a rotational axis formed by stage flexures 153, 154. Stage 140 and frame 135 each have one or more blades (e.g., blade 120 and blade 125, respectively) coupled to and extending from them. For example, blade 120 is coupled to stage 140 and blade 125 is coupled to frame 135. Applying a voltage difference between blades 120 and 125 can cause stage 140 to pivot. Similarly, frame 135 may be pivotally coupled to an outer stationary frame (not shown) using frame flexures 151 and 152 on diametrically opposed sides of frame 135. The outer frame may be a stationary frame or, alternatively, may also be designed to move relative to yet another outer frame structure. Frame flexures 151 and 152 suspended frame 135 in a cavity formed by the outer frame such that frame 135 is free to pivot around a rotational axis formed by frame flexures 151 and 152. Frame flexures 151 and 152 are orthogonal to stage flexures 153, 154, thereby enabling a reflective element coupled to stage 140 to be pivoted in two dimensions (e.g., rolled and pitched). Blade 125 remains fixed relative to blade 120, while blade 120 can rotate—such as by tilting or pivoting—as illustrated in FIG. 1A and FIG. 1B. Accordingly, blade 125 is referred to (e.g., designated) as a “fixed blade,” while blade 120 is referred to (e.g., designated) as a “movable blade.” Blade 126 is fixed relative to blade 121, which is rotatable as shown in FIG. 1A and FIG. 1B. Thus, blade 126 is referred to (e.g., designated) as a “fixed blade,” and blade 121 is referred to (e.g., designated) as a “movable blade.” Blade 120 extends in a direction perpendicular to the undersurface of stage 140 and blade 125 extends in a direction perpendicular to the undersurface of frame 135. An electric potential applied between blades 120 and 125 may cause an attraction between blade 120 and blade 125. Because blade 120 is coupled to stage 140, an attraction of blade 120 towards blade 125 causes stage 140 to pivot about the rotational axis formed by stage flexures 153, 154. For example, stage 140, and the corresponding blades