How Small is Too Small?By Gene Frantz
TI Principal Fellow and Business Development Manager, DSP

As I have stated, the use of SoC will increase as we are able to pack more and more converging technologies into a single portable device. But simply because we can integrate doesn’t mean we should do it. It will not always be practical to do, nor will it be the right thing to do.

Beyond the fact that color displays are the de facto standard for all portable equipment, nothing else concerning displays for portable devices is certain. That leaves us with an important, fundamental question that must be answered: How small is too small?

At the extreme end, some cellular telephones have already gone beyond what can reasonably be called “handheld”; some models should probably be called “fingertip” phones. Voice command partially compensates for their minuscule keyboard size; and where voice does not work, the user can revert to stylus or fingernail dialing.

Unfortunately, the screens on these small devices are practically unreadable. They may work for alphanumeric information, but they are simply too small for viewing high-quality color graphics. On the PDA front, we have the opposite dilemma. We have a screen size that is perfect for high-quality graphics, but it comes at the expense of the entire keyboard. Using the stylus as the sole input device may be acceptable to early adopters, but is it going over well with mass-market consumers?

The entire size argument is based on the premise that we will continue to build self-contained, multifunctional, portable devices that either fit in a pocket or clip on to our clothing. But with integrated WLAN capabilities already on the horizon, we owe it to ourselves to consider separating the display from the device itself.

That next-generation technology could very well include some type of near-to-eye (NTE) high-resolution micro-display that runs wirelessly from a wearable digital processor. All NTE microdisplays require some type of head-mounted device (HMD) in the form of eyeglasses, goggles, visor, or a headband (unless the display is held up to the eye by hand). While an HMD may appear at first glance to be an impediment to mass-market appeal, it may prove to be no more disadvantageous than an unreadable display on a fingertip-sized device.

Just in case you are still a skeptic, let me point to the equivalent concept for hearing. For many years hearing aids for the hard of hearing, had as its first priority, have been ultra-small so they could fit into the ear without anyone knowing of their existence. But with the advent of the cell phone, we now see people with the ugliest contraptions hanging on their ears in the name of “hearing aids”. But in this case the hearing aid it not for the hard of hearing but for the avid cell phone user. In the same way NTE microdisplays will certainly be accepted as a status symbol just as the Bluetooth headset is now.

If I look well into the future I am confident that the ultimate solution is obvious. It will be to remove all the I/O functions from the device and relocate them in the human brain (perhaps a new meaning to Blue tooth). That is not as farfetched as we might think. Cochlear implants are a perfect example. A hearing aid magnetically transmits digital data through the skin to the implant, where it is converted back to electrical signals and connected to nerve endings. Similar advances are being made with visual equivalents. SoC technology will be part of that solution. But as of yet, such a device has not yet seen the light of day.