Apple has been awarded patent for a new touch screen LCD technology that may suggest how the company might be able to reduce weight and thickness of next generation iPhone displays by combining different touch-sensing elements, reports AppleInsider. Labelled as “Touch screen liquid crystal display”, the newly patented LCD screen technology integrates the touch sensors with the actual display circuits, reducing the space taken up by the screen in contrast to the current technique, which places the touch sensors on top of the screen leading to a thicker display.
Quoting the source:
LCD touchscreen technology used in the current iPhone 4S, for example, is “glass-on-glass” or “on cell,” meaning the touch sensitive capacitive element is sandwiched between a display unit’s top glass and a protective Gorilla Glass layer. Below the LCD’s top glass is the liquid crystal array, a bottom glass and backlight assembly.
In a traditional configuration, colors and brightness are achieved through use of thin film transistors (TFT) overlaid on the top or bottom mother-glasses. The transistors apply a charge to the liquid crystals, which are held in cells, changing their orientation and allowing backlight transmission for the desired pixel color or brightness.
In-cell technology removes the top substrate, or glass layer, by combining the liquid crystal and touch sensing elements into a single structure. As seen in the patent filing, there are multiple ways of integrating the elements.
Apple explains in the patent filing:
“By integrating the layered structure of an LCD and a touch sensor, a variety of benefits can be achieved. This integration can include combining or interleaving the layered structures described above. Integration can further include eliminating redundant structures and/or finding dual purposes (e.g., one purpose for the touch function and another for the display function) for particular layers or structures. This can permit some layers to be eliminated, which can reduce cost and thickness of the touch screen LCD, as well as simplify manufacturing”.
The new LCD technology would be of greatest benefit to the iPhone and other iOS devices, but it could easily make its way into other types of devices as well.