The Mannheim company Vibrosonic developed the most unusual hearing aid in the world, a “contact lens for the eardrum”. The tiny man’s loudspeaker, more precisely the micro-actuator, is placed directly on the eardrum, while with conventional devices the sound still has to travel a distance in the air. In this way there are sound distortions that impair intelligibility. The acoustic contact lens is equipped with a particularly small microphone. It generates converts acoustic to electrical signals. These in turn are transferred to the actuator, which directly excites the eardrum. In healthy people, sound also stimulates the eardrum directly.
Battery is charged with infrared light
The device is equipped with a battery and a photo sensor for power supply. Robert Hahn from the Fraunhofer Institute for Reliability and Microintegration (IZM) in Berlin and colleagues from the Technical University of Berlin are responsible for the further development of this battery. The aim is to develop a battery that can be charged quickly. It is charged by an external device that emits infrared light into the ear canal. It is captured by a photocell and converted into electrical energy that flows into the battery. “It has to be charged every day,” said Hahn.
The requirements for the only 0.7 millimeter thick electricity storage are extreme. It is said to have a high energy and power density and to easily survive 2000 charge and discharge cycles. The device stays in the ear for as long as three years. Then it has to be replaced
Voices are no longer distorted
The device is currently being clinically tested. The researchers expect it to be mass-produced in 2021. A third of over 70 year olds need a hearing aid. Many do not because the distortion is so great that they can hardly understand anything more than without a device. There is no problem with the new device because the eardrum is stimulated directly. The wearer can hear a wider range of sounds and has no trouble locating the direction from which voices are coming. This makes it easier to understand, especially when there is a lot of background noise like at a party or a meal with many people.