Review of Electrothermal Micromirrors

Area of Science:

• MEMS and Microfabrication
• Optomechanics
• Actuator Technology

Background:

• Electrothermal micromirrors are crucial for applications requiring large angular scanning and linear motion.
• Their design, often lacking a torsional bar, facilitates linear displacement.
• These devices are increasingly important in various technological fields.

Purpose of the Study:

• To review electrothermal micromirrors based on diverse thermal actuators.
• To analyze the mechanisms of U-shape, chevron, thermo-pneumatic, thermo-capillary, and thermal bimorph actuators.
• To highlight the versatility of bimorph-based designs for tip-tilt-piston motion.

Main Methods:

• Review and analysis of existing literature on electrothermal micromirror designs.
• Examination of the operational principles of different thermal actuator types.
• Categorization of micromirrors based on actuation mechanisms.

Main Results:

• Electrothermal micromirrors enable significant angular and linear movement.
• Various thermal actuators (U-shape, chevron, thermo-pneumatic, thermo-capillary, bimorph) exhibit distinct mechanisms.
• Bimorph-based electrothermal micromirrors are particularly versatile, supporting tip-tilt-piston motion.

Conclusions:

• Electrothermal micromirrors are a significant advancement in micro-mirror technology.
• The choice of thermal actuator dictates the micromirror's motion capabilities.
• Future developments may involve integrating electrothermal designs with electromagnetic or electrostatic actuation for enhanced functionality.