Rohm Develops Technology to Hear Sound on Corner of Mobile Phone

Apr 27, 2012
Fumitada Takahashi, Nikkei Electronics
Sound can be heard by attaching the ear to a corner of the phone.
Sound can be heard by attaching the ear to a corner of the phone.
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Rohm Co Ltd developed a technology that enables to hear sounds by attaching an ear to a corner of a digital device such as mobile phone.

The technology uses a phenomenon called "cartilage conduction," where sounds are conducted to a hearing system via ear cartilage. And the company developed a chip equipped with a power supply circuit, amplifier and voice processing circuit, which are needed to realize the new technology.

At first, Rohm plans to promote the new technology to mobile phone makers, etc as a new phone user interface for loud environments.

Cartilage conduction is a phenomenon that Hiroshi Hosoi, professor, Head and Neck Surgery, Dept of Otorhinolaryngology, Nara Medical University, found in 2004. By attaching ear cartilage to a vibration source, the vibration is transmitted to the inner ear. In the phenomenon, "cartilage air conduction sound" plays a major role (the vibration of cartilage becomes sound inside an external ear canal and is transmitted to an eardrum).

Cartilage conduction is different from other bone conduction mechanisms. For example, sound is transmitted to a hearing system just by softly attaching an antilobium (a cartilage protrusion located outside an earhole) to a vibrator. And, when the antilobium is pressed to the vibrator, sound volume increases. Because the antilobium covers the earhole, it is possible to hear sounds while blocking external noise.

Rohm developed the cartilage conduction technology used for the chip in collaboration with a research group led by Hosoi.

Hosoi plans to deliver a lecture on the details of cartilage conduction on the first day of the 113th Annual Meeting of ORL Society of Japan, which will take place May 10 to 12, 2012, in Niigata Prefecture, Japan.

Rohm expects that the new technology will be employed for smartphones, and it prototyped a case equipped with the newly-developed chip and vibrator for Apple Inc's iPhone. The company will exhibit the case at the exhibition that took place along with the meeting.