Mechanical Technology April 2016

⎪ Structural engineering materials, metals and non-metals ⎪

This is what a city street might look like with a combination of different dis- play elements on the solar roadways of the future. Photo: Scott and Julie Brusaw.

Bandra Ohm will be a residential tower block, shaped like the Greek letter omega and inspired by the fluidity and movement of water. Photo: James Law Cybertecture International.

SCHOTT makes ultra-thin glass using a down-draw process, where the glass is continually drawn directly from the smelter through a nozzle, forming a glass ribbon. This ribbon is then coiled for further processing. Photo: SCHOTT.

can be made powerful enough so that the absorbed energy can be used to increase the range of an electric vehicle. Display screen glass technology Everyone has display screen glass at their fingertips on a daily basis, whenever they use their smartphones. In Germany alone it is used by 44 million citizens – and the trend is still upward. It seems that wherever we go we are continually accompanied by ultra-thin display glass. And, of course, it needs to be particularly impact-proof and scratch- resistant, so that it can withstand normal stress. We also want it to feel good and be easy to clean – and it needs to weigh as little as possible. This creates a rather difficult balancing act for the producers. Glass continues to be an unrivalled material for touch screens. But we are seeing more and more power and func- tionality having to be accommodated in fewer and fewer square centimetres of space. This means that the heat pro- duced by our devices is increasing due to ever more powerful, yet smaller electronic components. The solution to the problem is ultra-thin display glass, glass being an ideal material for retaining its stability and shape despite rising temperatures. The secret of thin glass is in the ma-

terial composition. The constituent that has gained ground in the glass industry is aluminium silicate, which is highly re- silient and reduces reflection. Multi-touch screens are produced from float glass that has been chemically pre-stressed via ion exchange. A semiconductor film is then attached to the glass to add optical and capacitive properties. Production gets even more delicate when we look at ongoing developments in ultra-thin glass. Operating under the name KONFEKT, three major companies in the industry – SCHOTT AG, tesa SE and Von Ardenne GmbH – are currently working on a project to develop ultra-thin glass for use in organic electronics and OLED applications. The project is sup- ported by the German Federal Ministry for Education and Research. The aims are ambitious, researching all the various manufacturing and finish- ing processes in connection with ‘glass from the roll’, and indeed in such a way that glass can be used for functions in organic electronics, such as OLED technology. Users particularly appreci- ate the basic properties of glass, i.e, it is impermeable to gas and water and can protect sensitive componentry from moisture and oxygen ingress. The underlying process has been de-

veloped by the German glass manufactur- er, SCHOTT, which is using a down-draw process, whereby a glass sheet is drawn down through a cooling section. Accurate process control is applied to achieve the tightest of manufacturing tolerances with respect to uniformity of thickness for large yet very thin surfaces. The process makes it possible to produce glass to a thickness of 25 µ m – half the thickness of a human hair (50 µ m). Applications are already being found in biotechnology and sensor applications and the material is now available in sheets, wafers or rolls. Innovations and further developments of ideas such as these we will be show- cased at glasstec 2016 in Düsseldorf from 20 to 23 September, with selected outstanding innovations being high- lighted at a symposium called Glass Technology Live on 21 September, being held under the auspices of the VDMA Glass Technology Forum. q The glass can react to sunlight to automatically produce shade, to light up or to transform the incoming light into electric power. BMW is seeking a transparent and flexible carrier mate- rial that will make it superfluous to scrape ice off their cars.

Mechanical Technology — April 2016

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