New light-emitting-polymer technology unveiled

MARCH 27--Cambridge Display Technology (CDT; Cambridge, UK; www.cdtltd.co.uk) has improved the life performance of display devices based on light-emitting-polymer (LEP) technology, achieving more than 11,000 hours of operation for its blue polymer research devices. Over the past year, CDT has more than tripled the lifetime of its blue research devices. This advancement is a major step toward the commercial exploitation of LEP technology in several full-color, active-matrix applications such as Internet access devices, computer applications, and electronic products. The longer operating life is due to advances in LEP material formulation, improved deposition processes for the polymer and other materials, and novel device structures.

The improvements in processes and structures are directly transferable to red, green, white, and other polymer material colors. CDT expects that many of these improvements will be transferable to full manufacturing processes.

Early this year, CDT researchers surpassed the 11,000 hours blue material operating mark, measured as the time from initial brightness to half the initial brightness. The method used is based on the industry standard for measuring the decrease in brightness of emissive-type displays, such as plasma, CRT, and LEP, which is a type of organic light-emitting display.

Testing at higher brightness and operating temperature was used due to the long operating time needed to measure the result and correlated with ongoing testing at room temperature and typical commercial display brightness levels of 100 cd/m2.

LEPs generate their own light, eliminating the need for a backlight, which is required in LCD displays. This makes them thinner and lighter weight, as well as more power-efficient. LEP displays also have higher contrast with richer color, offering superior quality images that can easily be viewed from wide angles. Additionally, LEP materials are plastics that can be dissolved into solvents that allow deposition using ink-jet printing on glass or plastic substrates. This provides a potential manufacturing advantage that could significantly change the way displays are produced and open new markets and opportunities for lower cost displays on flexible substrates that can conform to curved surfaces.