How it works: The technology of touch screens

17.10.2012

No matter which solution wins out, it is clear that pro-cap technology is the best method for touch screens on mobile devices -- at least for the foreseeable future. Still, there are some changes already showing up in touch screen technology.

For example, some panel makers are creating "in-cell" touch panels, where one of the conductive layers actually shares the same layer as the thin film transistors (TFTs) used to switch the display's sub-pixels on and off. (These transistors are fabricated directly on the semiconductor backplane of the display.) This approach not only reduces the electromagnetic noise in the system, but also uses a single integrated controller for both the display and the touch system. This reduces part counts and can make the display component thinner, lighter, more energy efficient and more reliable.

This approach only makes sense for very high volume products, such as a smartphone from a major vendor that is expected to sell millions of units, because the panel will have to be made specifically for that unique model. The first products using "in-cell" touch technology have already appeared on the market, such as the new

, but it looks as though it will take years before this approach will become a widespread solution.

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