Laser speckle reduction by a hybrid MEMS diffuser device with continuous height profile

The hybrid MEMS diffuser device based on Si wafer and fire resistant 4 printed circuit board (FR-4 PCB) was designed in order to obtain a low-cost device with large aperture for laser speckle reduction. Reflective diffuser with continuous height profile was fabricated on Si wafer by micromachining technology. FR-4 PCB was used to fabricate the vibrating structure by printed circuit board (PCB) manufacturing process. The hybrid MEMS diffuser device including diffuser and vibrating structure was driven to vibrate by electromagnetic force with a frequency of 66 Hz. The laser speckle reduction of 71.8% was obtained for the MEMS diffuser device.