One Glass Solution

One Glass Solution^[1] is a touchscreen technology which reduces the thickness of a display by removing one of the layers of glass from the traditional capacitive touchscreen stack. The basic idea is to replace the touch module glass by a thin layer of insulating material. In general, there are two ways to achieve this.

One approach to OGS is called "sensor on lens." (In this case, the "lens" refers to the cover glass layer.) You deposit an Indium tin oxide(ITO, used as electrodes to sense touch) layer on the back of the cover glass and pattern it to create the electrodes. You add a thin insulator layer to the bottom of that, and then deposit a second ITO layer on the back of that, patterning it to create electrodes running at right angles to the first layer. This module then gets laminated onto a standard LCD panel. The other approach is called "on-cell" capacitive touchscreen. (Here the "cell" refers to the LCD.) A conductive layer of ITO is deposited directly onto the top layer of glass in the LCD panel, and then patterned into electrodes. A thin insulating layer is applied, and then the second ITO layer is patterned with the second layer of electrodes. Finally, the top polarizing layer is applied on top, and the display is completed by adding the cover glass.

For now, it appears that the sensor on lens approach has an advantage over on-cell solutions. The on-cell approach means that LCD makers would have to make two separate models of each panel: one with touch and one without. This could add cost to an industry that is already running on razor-thin margins. Also, on-cell touch is limited to the size of the LCD panel; sensor on glass modules can be larger than the LCD panel, providing room for the dedicated touch points that are part of many smartphone designs. However, due to how its made, sensor on lens are very fragile in comparison to on-cell. Damage to the cover glass will effect the functionality of the touchscreen.

Successor

Its successor is "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). The first products using "in-cell" touch technology have already appeared on the market, such as the new Apple iPhone 5, XOLO 8X-1000, vivo X3S.

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