Press Release

Flexible displays coming from Prime View International

At S.I.D. 2009, Ian French from Prime View International (PVI) gave an excellent presentation on progress with flexible displays. French firstly covered work on flexible LCDs, which IDTechEx recently wrote about after our visit to Hong Kong.

French said that companies that have demonstrated flexible LCDs include Samsung, Toshiba, Kent Displays and Sharp, but none of these have moved into mass production or are even planning mass production.

He stated the reasons for this is that high transparency, colourless substrates are needed with zero birefringence. This rules out steel and most polyimide substrates. PET, PEN and PES are viable in this regard but require low temperature processing - below 200 Degrees Celsius. This makes active matrix backplanes difficult to make, because a-Si is normally processed at 350 Degrees Celsius.

While lower temperature TFTs can be produced, their reliability in mass production is unproven. There are also mechanical issues, where current LCDs rely on the rigidity of glass, which mean that the existing LCD infrastructure could not be used to make flexible LCDs. Flexible LCDs were targeted for cellphone displays because they would be more robust and thinner, but as LCDs on glass became much thinner it negated the demand. According to French, the lack of demand and technical issues mean that flexible LCDs have not been commercialised.

E-readers
Glass e-readers have been available since 2002, first launched by Sony. PVI began mass production of e-reader modules in 2005. PVI only sells the display modules, making the a-Si backplane and laminating an E-ink foil on top and then connecting the silicon chip controllers. It sells these to companies making e-book readers, of which there are now 20 on the market. The most successful has been the Amazon Kindle reader.

According to several sources, the cost of the 6' display module in the Kindle is $60, versus $7 for a 6' LCD display. Of all the e-readers on the market, PVI supply the display modules to approximately 90% of them. French described that unlike an LCD display, which is driven at +/-6 volts, e-paper is driven at a higher voltage, usually +/-15 volts. PVI therefore puts two transistors in series for each pixel rather than one as you would have with an LCD display to reduce the leakage current.