[CEATEC] KDDI Eliminates Speaker from Smartphone

Oct 7, 2011
Tetsuo Nozawa, Nikkei Electronics
The "New Auditory Sensation Smartphone." The hole for a speaker is sealed (the hole is located at the upper part of the phone).
The "New Auditory Sensation Smartphone." The hole for a speaker is sealed (the hole is located at the upper part of the phone).
[Click to enlarge image]

KDDI Corp showcased a smartphone that does not have a traditional speaker at CEATEC Japan 2011.

At the trade show, visitors could experience the smartphone, which the company calls "New Auditory Sensation Smartphone," first hand.

The new smartphone has 0.6mm or thinner piezoelectric elements in place of a traditional speaker. And the hole for a speaker is sealed with a tape.

When the user is talking on the phone, the piezoelectric elements vibrate instead of a speaker. But when the smartphone is on a table or just held by hand, the voice on the other end of the line can hardly be heard. Only after putting the smartphone to the user's ear, it can be heard.

The sound of the new smartphone is clearer than that of a normal smartphone. It is not necessary to completely cover the ear. When the smartphone touches the earlobe, etc, the sound can be heard.

KDDI demonstrated that it is possible to have a conversation on the phone even when the user is listening to music by using earphones or when the user's ears are covered by high-end headphones and ambient sound can hardly be heard by the user.

Different from bone conduction

As for the reason why sound can be heard when the smartphone is put to the ear, KDDI said, "It's not clear. But I think the the ear canal (earhole) is like a resonator and there is a standing wave."

Commenting on the difference from bone-conduction headphones, etc, KDDI said, "With the new technology, sound is heard by the eardrum." In the case of bone conduction, sound vibration is conducted to the middle ear, etc via the skull. But the output of the new smartphone's piezoelectric elements is too low to do that, the company said. In fact, when I put the new smartphone to my head, I could not hear sound.

KDDI said that the new technology has many more advantages than its potential to change the way how sound is heard.

"It eliminates the need to make a hole in the chassis of a smartphone for a speaker, and water and crack resistance can be enhanced. Also, it improves design freedom," the company said.

Furthermore, the power consumption of the piezoelectric elements is lower than that of a speaker. And the slimness realized by them means lower costs, the company said.

KDDI plans to release a smartphone using the new technology in fiscal 2012.