Organic lights hold promise of softer glow

Cost-efficient and eco-friendly, lights powered by light-emitting diodes are taking off but may soon be upstaged by their organic cousins.

Engineers have high hopes that OLED (organic light-emitting diode) lights, which are flat and produce a softer light than LEDs, will become a new option in the lighting industry and cultivate the market further.

“We’ve been researching them for 10 years and feel that the technology is nearly ready for practical use,” said Yasuki Kawashima, manager of the solid-state lighting application engineering and development department at Humitsu Corporation, which makes OLEDs.

Unlike LEDs, which use tiny bulbs that create intense points of light that can be hard on the eyes, OLEDs usually come in panel form, with a powdery organic compound sandwiched between electrodes and glass. When electricity runs through the compound, the entire panel glows softly, making OLEDs suitable as a surface light source.

Although LEDs can be used as surface light sources by covering them with translucent covers, some of the light is inevitably blocked and wasted.

Holding up a 10-sq.-cm, 2-mm thick OLED panel, Kawashima showed just how soft the light can be.

“You might feel that (OLED) light is a little dim, but it doesn’t make you feel uncomfortable even if you look directly at it. . . . I think it’s a friendly technology,” Kawashima said, adding that OLEDs, unlike fluorescent tubes, don’t contain harmful chemicals like mercury.

OLED panels also have characteristics that might lend themselves to more creative uses.

Kawashima brought out a desk lamp that uses OLED panels. Normally, this kind of lamp uses fluorescent tubes or an incandescent bulb, making the connecting part quite thick. Since OLED panels are thin, however, the top of the lamp, which is normally larger, can be just as thin as the panels.

He also showed off a transparent OLED panel that remains see-through even when it is emitting light.

At a lighting exhibition at Tokyo Big Sight last month, several companies showcased how creative they can be with OLED panels.

Humitsu Corporation displayed a ceiling lamp that looked like a pine cone, with several panels vertically arrayed at its center.

While anticipation is high, industry insiders said it will be years before consumers start seeing OLED lights on store shelves.

In addition, the manufacturing costs for OLEDs remain quite high. The key to reducing costs will be mass production. Humitsu said the technology for starting mass production with acceptable quality control is still on the drawing board.

He also said LEDs still have an edge over OLEDs in luminance efficiency and lifespan, so there are still improvements to be made.

Kawashima of Humitsu shared Kurosawa’s view. He speculated that consumers will start seeing OLED lights in public facilities and stores starting in 2015 but said it will be a few more years before the panels drop down to a relatively reasonable price.

According to market research firm Fuji Keizai Co., the OLED market will start growing this year. By 2020, the global market is expected to be worth ¥1.3 trillion and the Japanese market around ¥100 billion.

The LED market is also growing. In 2012, the shipment value of LED lights in Japan reached ¥420 billion, almost double what it was in 2011.

Industry observers say OLEDs and LEDs are likely to be different enough to coexist.

“I don’t think they will be replacing LEDs. There will be needs for both,” said Kurosawa, referring to their projected point and planar lighting roles.

For instance, ceiling lights in shops can be replaced with OLED panels while LEDs can be used as spotlights to illuminate products for sale.

Likewise, LEDs are good for car headlights and OLED panels for interior lights.

Humitsu also said that it’s possible to manufacture flexible OLED panels, which means one could be rolled around a pillar in a house, expanding the number of lighting possibilities.

The firm said it has been working with homebuilders to explore how the panels might be used in houses of the future.