Dear Mr. Jones:
Now Touch Guy feels threatened! For many months he has been extolling the virtues of projected capacitive touch and now you think it might not be the good-for-everything solution. Ok, I will reluctantly look into the crystal ball, aka Touch International’s skunk works, to provide you the answers you seek.
In-cell technology has long been rumored to be the projected capacitive killer. With in-cell, the touch sensors are the pixels in an LCD display. By light or capacitance sensing, when the thin film transistors are not busy switching the liquid crystal material, they can sense touch and send the information back to the LCD controller. There are already two or three products using this technology but its complexities and cost have delayed large scale production.
Many people are experimenting with corner camera technology of the sort used in big touch displays. As cameras get smaller and cheaper, this technology holds promise for future use in hand-held devices. The advantage over projected capacitive is that it is better at integrating a standard pen into the system. Higher power and the need for ambient light, among other things, add to the difficulty of wide-scale integration.
Fiber bundles with one camera offer some benefit; so far, the cost of making a low profile product in volume has been evasive, but this technology offers the ability to sense a pen tip as well as two touch applications. Right now it lacks the ability to do true multi-touch, so it may lag.
You should remember that like these emerging technologies, projected capacitive is not static and may one-up itself. Pen input, proximity sensing (up to one meter) and no-touch-touch applications are on the way.
So now that you’ve seen “the future” don’t forget that Touch International’s MARS product, is available today and offers high resolution pen input and full multi-touch capabilities.
There are more than 2000 patents on touch sensing, so Touch Guy does not claim to know the future but he has no fear – projected capacitive is here to stay.