Microheater-Integrated Microlens Array for Robust Rapid Fog Removal

In extreme environments, fog formation on a microlens array (MLA) surface results in a device failure. One reliable solution for fog removal is to heat the surface using a microheater. However, due to the surface interference, the combination of these two microdevices remains elusive. In this study, we introduce lift-off and electroless plating into femtosecond laser processing to fabricate a microheater integrated MLA (μH-MLA) on the same substrate with high light transmittance, durability, and fog removal efficiency. Laser-induced micro-nano grooves enable the microheater to be tightly coupled with the MLA and have high heating performance, thus maintaining a stable performance for over 24 h during continuous operation as well as under long time ultrasonic vibration and mechanical friction. With a rapid response time (τ_0.5) of 17 s and a high working temperature of 188 °C, the μH-MLA removed fog that covers the entire face within 14 s. Finally, we prove the use of this fabrication method in large areas and curved surface environments. This study provides a flexible, stable, and economical method to integrate micro-optical and microelectrical devices.