MEMS Movable Device Cantilever Coupling for Large Deflection

The movable device is divided into distinct functional segments: a mirror unit with a large diameter mirror for light reflection, a torsion bar for rotational movement, and cantilever parts for structural support. This segmentation allows each component to be optimized independently, enabling a large mirror diameter without proportionally increasing overall device complexity.

The patent transitions from planar two-dimensional light scanning to three-dimensional light scanning by incorporating a torsion bar that enables rotation around a vertical axis, in addition to the horizontal scanning motion. This dimensional expansion allows the light beam to scan a wider spatial volume, effectively increasing the functional scanning capability without merely enlarging the mirror diameter.

The patent utilizes the elastic deformation and vibration characteristics of the cantilever parts to achieve rapid angular deflection of the mirror. By designing the cantilever with appropriate dimensions and material properties, the system can achieve large deflection angles through controlled vibrational motion, reducing the need for continuous high-power actuation and thereby lowering overall power consumption.

The patent optimizes the physical parameters of the cantilever parts, including their length, width, thickness, and material composition, to achieve the desired deflection angle with minimal energy input. By carefully selecting these parameters, the system maximizes the mechanical advantage and reduces the actuation force required, leading to lower power consumption and reduced noise from actuator operation.

The patent applies local quality by making the cantilever parts have non-uniform cross-sectional dimensions along their length. The width and thickness of the cantilever are greater at the fixed end to provide structural strength, and gradually decrease toward the free end to reduce the bending elastic modulus and enhance deformation capability. This gradient structure allows the cantilever to maintain sufficient strength while achieving the required flexibility for large deflection angles.

The patent employs composite material construction for the cantilever parts, combining materials with different mechanical properties to optimize both strength and flexibility. The composite structure allows the cantilever to exhibit high stiffness near the fixed end for structural support while maintaining high flexibility at the free end for large angular deflection, effectively resolving the contradiction between strength and deformability.