17‐3: Towards Flexible Glass: Ultra‐Thin Glass with Tight Dimensional Tolerance and High Strength Achieved by Ion Exchange

Abstract

Ultrathin aluminosilicate glass AS 87 eco, has been produced by SCHOTT proprietary downdraw hot-forming method as thin as 50 μm. A tight thickness tolerance of ± 10um, with a TTV <10 um across an area of 400×500mm, and a surface roughness smaller than 1 nm have been achieved in mass production. Compared with other ultrathin glass, the uniqueness of AS 87 eco lies in its the outstanding chemical strengthening performance, where the surface compressive stress can reach over 800 MPa after an ion-exchange process in molten KNO3 salt bath. The high alumina content also accelerates the Na-K diffusion, and an ion exchange depth of 20 μm can be achieved after toughening at 390C for 2h. Combining such chemical strengthening with fine edge treatment results in an extremely high bending strength over 1GPa, allowing a safe bending radius as low as 3mm for 70 μm thick glass. As such, this ultrathin glass enables a highly scratch-resistant glass cover for applications such as foldable displays and any other applications requiring the combined properties of strength, transparency, flexibility, and scratch-resistance properties. Low breakage strength is the most significant obstacle for a wide application of ultrathin glass, and aluminosilicate glass can be strengthened well after ion exchange. SCHOTT is the first supplier in mass production of directly hot-formed ultrathin aluminosilicate glass eliminating the need for chemical thinning.

Room‐temperature bonding method of bioactive ultrathin glass film on titanium by a dissolution‐polymerization reaction

“…15,16 It possesses high potential for applications such as electronics, vehicles, lighting, and so on. [17][18][19] Their application of ultrathin glass is still in the category for manufacturing electronic devices and products. Recently, we developed a freestanding ultrathin glass film (UGF), which has the thickness of a few micrometers and can be directly bonded onto a substrate at room temperature.…”

“…Freestanding ultrathin glasses with the thickness of micrometers have been paid much attention in recent years due to their outstanding characteristics in terms of flexibility, transparency, surface smoothness, gas barrier capability, and so on 15,16 . It possesses high potential for applications such as electronics, vehicles, lighting, and so on 17‐19 . Their application of ultrathin glass is still in the category for manufacturing electronic devices and products.…”

Analysis of fracture mechanisms of ultrathin glass for flexible cover window under pen drop conditions

“…Similar to the 2‐point bending test, fracture mostly occurs from the bottom side of the glass during bending under pen drop condition. The failure of the upper surface was thought to occur due to reverse bending that is induced by stress wave and indicated as second maximum stress in Figure 7 on the upper side of the glass, if the size of the surface flaws on the bottom surface, where maximum deformation and stress occurred, were relatively small or did not exist 27,32 . Thus, based on the high‐speed camera and FE simulation results in Figure 7, the fracture of the chemically strengthened UTG can be understood to indicate that the radial cracks were primarily generated by bending of the lower surface in the central area within a very short time.…”

“…Few studies on the fracture behavior of UTG to improve impact resistance have been reported, except a few works on the chemical strengthening characteristics of UTG for foldable applications 26,27 and the fracture mechanism of bilayer structures with pristine UTG, via static, and dynamic indentation tests 28,29…”

53‐2: Composite Films with Ultra‐Thin Glass and Polymer for Novel Optically Functional Films

“…This development has led to a strong demand for thinner display materials, including polymer films such as polarizer, as well as glass. Ultra-thin glass (ranging from 30 to 150 μm in thickness) has been proposed as one such materials [2] [3]. This material has a unique property, namely, it is as as flexible as polymers.…”