A New Organic Compound Cellphone Screen
THE CELLPHONE is an organic part of life here — and now organic matter is a part of the cellphone. A Japan-Korea joint venture called Samsung NEC Mobile Display is incorporating organic compounds into keitai screens, resulting in radiant screens with less bulk, glare, battery drain, and manufacturing cost.
With video, animated graphics, and other multimedia services dialing in to the wireless Web here, the limitations of traditional liquid crystal displays — aka LCDs — have become painfully evident, forcing screen makers to explore new areas of research, including the natural sciences. This has led to the realization that organic electroluminescence — used by many forms of life to emit light — offers a way to create superior small screens.
“Because of its self-emitting properties, organic EL can transmit light at a very high speed, in a full-color range, while using less energy,” says Kenji Okada, division manager of NEC Display Device Development. “It transmits video at about 1,000 times the speed of LCD.”
How does it work? The display is composed of a thin organic layer sandwiched between two metallic plates. The organic (i.e. carbon-containing) material emulates the self-luminescent characteristics of certain organic tissues present in some living creatures. When an electric charge is applied to the metallic plates and across the organic layer, light is instantly emitted.
“It’s the same principle as the firefly,” explains Okada. “Its organic matter is not inherently glowing — it takes a jolt of electrons to display the natural luminescence of its matter.”
In comparison, an LCD derives its luminescence from a backlight that emits light through a layer of liquid crystals. The crystals, switched on or off by an applied voltage, determine the light intensity and color mixture of the image displayed by the screen’s pixels — a slow, battery-sapping process.