Rather than coming equipped with speakers, Google Glass will create audio by producing sound vibrations in your skull.
Google has filed a patent application in the US for its Google Glass technology, revealing the gadget's technical specifications — including headphones that operate via bone conduction to transmit sound to the wearer.
It's not exactly new technology, and it definitely has its limitations, but it's useful in that it doesn't block the wearer's ears, meaning ambient noise can still be heard clearly — useful in a piece of technology that seems to be designed as an HUD for life.
The patent convolutedly reads:
A wearable-computing system comprising: a support structure comprising a front section and at least one side section, wherein the support structure is configured to support the one or more optical elements; a means for receiving an audio signal; and a means for vibrating at least a portion of the support structure based on the audio signal, wherein the means for vibrating is located on the at least one side section; wherein the support structure is configured such that when worn, a first portion of the at least one side section has an inner wall that contacts the wearer so as to vibrationally couple to a bone structure of the wearer; and wherein the means for vibrating is located on a second portion of the at least one side section having an inner wall that does not contact the wearer, such that when the support structure is worn, the means for vibrating vibrates the support structure without directly vibrating a wearer.
A secondary vibration transducer could be added so that the wearer could give instructions to the headset via voice command.
Other details in the patent application reveal that the device may include wireless or wired communications compatibility:
In Fig. 3, the communication link is illustrated as a wireless connection; however, wired connections may also be used. For example, the communication link may be a wired link via a serial bus, such as a universal serial bus or a parallel bus. A wired connection may be a proprietary connection as well. The communication link may also be a wireless connection using, eg, Bluetooth RTM radio technology, communication protocols described in IEEE 802.11 (including any IEEE 802.11 revisions), cellular technology (such as GSM, CDMA, UMTS, EV-DO, WiMAX or LTE) or Zigbee RTM technology, among other possibilities.
You can read the patent application online in its entirety here.