Japan Display Inc showcased a so-called "cover glass-integrated touch panel," which is made by forming capacitive touch sensors on the back of the cover (strengthened) glass located on the surface of a smartphone or tablet computer.
The panel was exhibited at FPD International 2012, which runs from Oct 31 to Nov 2, 2012, in Yokohama, Japan. The company started volume production of the panel in August 2012.
At its booth, Japan Display showed a 4.3-inch 1,280 x 720-pixel LCD panel combined with the touch panel by using ultraviolet curable resin. Because the touch panel eliminates the need for an external touch panel, it becomes possible to reduce thickness and the interface reflection of external light and backlight, increasing the visibility of the panel.
The cover glass-integrated touch panel was made by chemically strengthening a large glass substrate by ion exchange, packaging the surface of the chassis, forming sensor electrodes, finishing the surface and, then, cutting and processing the glass substrate. Japan Display chemically polishes the glass substrate after cutting it to prevent the decrease in glass strength, which is caused by cracks after the cutting. The strength of the touch panel is 550MPa on average, the company said.
As glass, Japan Display used the "IOX-FS" strengthened glass, which Corning Inc developed for cover glass-integrated touch panels. The glass is processed by an outside company.
There is another technology that eliminates the need for an external touch panel. It is a so-called "in-cell" technology, which equips an LCD panel with the function of touch sensor. And Japan Display has already started volume production of its in-cell panel called "Pixel Eyes" (See related article).
"We will provide the cover glass-integrated panel and in-cell panel in response to user requests," the company said.