By Calvin Hsieh – Senior Analyst, DisplaySearch and Jennifer Colegrove – Vice President, Emerging Display Technologies, DisplaySearch

Projected capacitive touch panels typically use one or two sheets of glass to create the sensor, which, in addition to the cover lens (also called the cover, window, or glass), can result in a complex structure. Because of this, touch module makers are trying to integrate the sensor into the cover lens in order to reduce material cost, thickness, and weight.

Each module maker has come up with a different name for this process, including one glass solution, window integrated sensor touch, on lens advanced touch technology, direct patterned window, and G2. All of these are variations of the sensor-on-cover method. Each case uses a single piece of glass (or perhaps plastic with a laminated film) as both the cover lens and sensor substrate.

Some touch module makers already offered this kind of structure; however, it was not until late 2010/early 2011 that many brands, such as Nokia, Apple, and Samsung, began requesting that portable devices be made even lighter, thinner, and at a lower cost. This has helped to popularize the sensor-on-cover method in 2011.

Another method for integrating touch screens involves on-cell and in-cell touch. On-cell and in-cell are preferred by display manufactures that can leverage their display and touch capability. Eventually, touch screens won’t have their own substrate, instead, it will be considered “invisible.”