A Robust Infrared Transducer of an Ultra-Large-Scale Array

Abstract

A robust micro-electro-mechanical systems (MEMS) infrared thin film transducer of an ultra-large-scale array was proposed and fabricated on a 4-inch silicon wafer. The silicon substrate and micro cavities were introduced. This novel transducer had excellent mechanical stability, time response, and state-of-the-art pixel scale. It could bear a load of 1700 g and its load pressure was improved by more than 5.24 times and time constant decreased by 50.7% compared to the traditional soft infrared thin film transducer. The array scale of its pixels exceeded 2k × 2k. The simulation and measured results of the transient temperature and radiation intensity were well consistent. Illuminated by a 532 nm laser with a frequency of 50 Hz and 50% duty cycle, the thermal decay time of the proposed transducer was 6.0 ms. A knife-edge image was utilized for spatial resolution test and the full width at half maximum (FWHM) of the proposed transducer was 24% smaller than the traditional soft one. High-resolution infrared images were generated using the proposed robust transducer. These results proved that the robust transducer was promising in infrared image generation.

Demonstration of thermal modulation using nanoscale and microscale structures for ultralarge pixel array photothermal transducers

“…The Al black coating contained nanoporous structures and possessed strong visible light-absorption and infrared ray emission abilities 24 , 26 . As presented in Fig.…”

“…The proposed 3D-NIT and 3D-IT transducers with the same DS in-plane pattern were fabricated through spin-coating, deposition, lithography and etching processes that were compatible with integrated circuit (IC) mass production technology (see supplemental Section S 3 ). We fabricated a 3D-NIT transducer with pixels exceeding 2000 × 2000, and the testing results demonstrated that the load weight was beyond 1700 g 24 . Since the 3D-IT transducer had structures and fabrication methods similar to those of the 3D-NIT transducer, it would still be advantageous in array scale and mechanical stability.…”

“…The pixels of the infrared emitter were connected to adjacent pixels, so there was still a thermal crosstalk problem, and the temperature contrast ratio was constrained 19 , 20 . Moreover, limited to the thickness of 2D thin films, the poor mechanical stability and larger array scale of the infrared emitter has become a challenge 24 .…”

“…A robust infrared emitter with a greater heat dissipation rate and mechanical stability was proposed and investigated by our group. Additionally, the array scale was enlarged to 2000 × 2000 24 . We introduced silicon (Si) microcavities to isolate the pixels and the Si substrate to maintain a relatively high-temperature contrast ratio.…”