A speaker works by moving vibrating a coil using magnetic waves, and the resultant vibrations are then passed onto a diaphragm that moves the air to create sound. Matsushita has developed a speaker that it calls the Sound Window. The Sound Window operates by vibrating a transparent film with air pressure.

Since the air causes the entire film to vibrate, there is hardly any loss in sound volume by a partial touch on the display. Although a high frequency range cannot be gained fully, power consumption in the sound reproduction is about 1/25 of the average speaker.

Read more on this interesting new technology link.