Communication Earplug Revolutionizes Hearing Protection (2000-2012) AFOSR-sponsored research has led to a communication earplug that revolutionizes hearing
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2000s
microwave devices and circuits for telecommunications and radar transceivers; and semi-transparent, touchsensitive screens for emerging multi-touch interface technologies. Another attractive aspect of this new type of thin film transistor is that the processing technology used to fabricate the devices is relatively simple and is compatible with inexpensive plastic and flexible substrate technology. The AFRL team found that the trick to controlling the conductivity and transparency of the devices is optimizing the size and density of the zinc oxide nanocrystals. They have demonstrated films that are 90 to 95 percent transparent, have metal-like electrical conductivities, and can withstand high temperatures for long periods without degrading. Bayraktaroglu and his team have used these devices to demonstrate the world's first thin-film microwave transistor operating up to 10 GHz and 100 times faster than any other thin-film transistor. This work is continuing toward the goal of achieving 100 GHz operation using finer lithography features and 2-D electron gas at the thin-film heterojunctions of zinc oxide (ZnO) and magnesium zinc oxide (MgZnO). They also have perfected the application of zinc oxide films onto various surfaces using a special technique called pulsed laser deposition, which employs an ultraviolet laser beam to remove zinc oxide nanocrystals from a source and deposit them as a thin film on the desired surface. These films are then processed into field effect transistors and transparent conductors using standard lithography techniques.99
protection for Air Force pilots and flight crews and could substantially reduce hearing loss and improve radio communication. This breakthrough research, led by Dr. Laura Ray of Dartmouth College, enabled the researchers, engineers, and product developers at Sound Innovations, Inc. to develop a new active noise reduction system, which is at the heart of the new earplug design. The new device is expected to impact the work of active-duty military personnel by protecting and enhancing their hearing, allowing clear, two-way communication in noisy environments and enabling them to effectively listen to sounds from a distance. “Dr. Ray worked out the mathematics to successfully conjoin noise control algorithms for the first time in a highly stable, hybrid system. This scientific breakthrough enables a much more robust approach to noise cancellation for the acoustically dynamic conditions encountered around aircraft engines,” said Dr. Willard Larkin, AFOSR Program Manager for the project. “One of the primary challenges was to develop an electronic module for the earplug that could operate for 15 to 20 hours on AA batteries. We were gable to use cuttingedge processor technology for developing a lower power electronics module,” said Ray. The earplug has high-fidelity audio for clear speech, wide frequency range, light t, head-borne weight, arand replaceable earn a small tips. It is stored in ched to pouch that is attached an airman's flight vest and cation signals delivers communication through the earplugs, which are worn under the helmet. The product was tested for design verification, evaluated for operational use, and then the first generation of earplugs was flight tested at over a half-dozen Air Force bases. In the interim, Sound Innovations, Inc. finalized the second-generation design, which has reduced power consumption, size, and weight. Secondgeneration prototypes are currently in field testing for commercial application.100