HTC has applied for a couple of patents, both of which are related to thin film speakers and the implementation in to a smartphone.
The first is for the process of manufacturing an electret diaphragm that allows for the diaphragm in a loudspeaker to be much thinner making it possible to fit better speakers in a smart phone.
A method for manufacturing electret diaphragms is provided. First, a dielectric film is attached to a frame by an adhesive material and a fastening element grips the peripheral area of the dielectric film on the frame. Afterward, the dielectric film is subjected to a metal sputtering process to form a conductive material layer thereon. Finally, the dielectric film is subjected to a polarizing process thereby forming an electret diaphragm.
The second patent discusses the implementation and how the system will work in a phone. A summary can be found just below…
An electronic device is provided. The electronic device includes a housing and an electro-acoustic transducer disposed on the inner surface of the housing. The electro-acoustic transducer includes an electret diaphragm, a conductive plate and at least one spacer. The electret diaphragm is positioned on the inner surface of the housing and has a film body and an electrode layer. The film body has static charges and the electrode layer is formed on the lower surface of the film body. The conductive plate has a plurality of openings and is stacked on the upper surface of the film body. The spacer is positioned between the electret diaphragm and the conductive plate to keep a predetermined distance therebetween.
If you want to take a read of the full patents, more details can be found over here and here.
Via: WMPowerUser
The thin film is transparent and goes over the display. The sound would emit from the display area. Overlaying a speaker on to a screen is not a completely new idea. It will be interesting to see HTC’s approach.