Full Color AM-LCDs on Flexible Glass Substrates
We have realized a full color 4-inch quarter-VGA amorphous Silicon AM-LCD on 75 μm flexible glass substrates. The overall thickness of the LC cell is <170 μm. With this work we demonstrate that the incorporated ultra-thin glass substrates have suitable properties to be compatible with a standard color AM-LCD process and achieve active matrix backplanes with reliable
Ultra Thin Flexible Glass Substrates
New applications in the electronics market ranging from foldable displays in mobile phones to wearable displays in clothes generate a high demand for flexible materials especially for substrates. The upcoming OLED technology shows some advantages in comparison with conventional LCDs and enables real flexible or shaped displays. Moreover, the wearable displays have a barely need for flexible electronic circuits. At a first glance polymer foils are the materials of choice for flexible substrates and for electronic circuits but in general they suffer from thermal instability as well as from high permeation rates for gases and water and hence chemical stability of critical materials such as LC's or low work function materials. In contrast, even ultra thin glass sheets have excellent barrier properties and show sufficient bending properties if they are thinner than 100μm. Flexible glass substrates down to a thickness of 50μm have been developed. The deposition of an organic coating helps to overcome significantly the lack of mechanical stability. Therefore, our flexible glass substrates can be used in conventional display manufacturing processes which include several thin film process steps. Moreover, they are suited for production of flexible PCB's.
Formation and Strength of Magnesia Whiskers
The formation of single-crystal magnesia whiskers during the compressive deformation of single crystals at room temperatures is described. These whiskers can have strengths of the order of millions of pounds per square inch. They are formed during fracture as a result of the discontinuous propagation of cracks which are mechanically relieving internal stresses resulting from plastic flow