CHIBA, Japan -- Organic light emitting diodes (OLEDs) have their positives and negatives.

On the positive side, OLEDs are incredibly energy efficient. Researchers have predicted that OLEDs could convert nearly 100 percent of the energy fed into them into light, far better than other new age light sources and far better than incandescent light bulbs which only use about 5 percent of their electricity to produce light. OLEDs are also about as flat as a credit card, potentially paving the way for tables, walls and windows to serve as sources of light in homes, hotels and restaurants.

The down side? OLEDs remain expensive, they wear out and producing large OLEDs remains a challenge technically and economically.

Rohm, the component maker, is showing off OLED prototypes that try to circumvent the problems by emphasizing style this week at Ceatec, Japan's version of the Consumer Electronics Show taking place this week in Chiba near Tokyo. That thing in the picture is an OLED wristband. It could be a piece of jewelry or a band for a watch. The dark lines are not flaws. That is a piece of washi, the Japanese paper used for place mats and other household items, incorporated into the wristband.

Rohm is also showing off small OLED table lights measuring about an inch wide and four inches tall. One of their OLED lamp prototypes consumes about 300 milliwatts, according to a company representative. The wristband is powered by a small lithium-ion battery. The OLED in the wristband measures about 0.3 millimeters thick. Rohm, ideally, would like to start selling OLED lights in about three years.

The prototype is one of many green exhibits on display this week at the show. Japan has been a major producer and consumer ofsolarpanels and energy efficiency technologies since the oil shocks of the early 1970s. Many manufacturers now want to expand on the export potential. Hence, instead of talking about screen size or screen resolution when it comes to TVS, a number of manufacturers are discussing how their consumer electronics can curb energy consumption compared to traditional products. (I'm here heading up a committee to pick the most promising technologies.) The show attracts about 100,000 attendees.

NEDO, the New Energy and Technology Development Organization of Japan, will also discuss a coalition that will try to produce OLED TVs that measure 40-inches on the diagonal. Right now, only Sony has an OLED TV, and it measures 11-inches across. Kateeva, a Silicon Valley start-up by way of MIT, says it has equipment to help make large OLEDs. We shall see. But in the meantime, couldn't you picture Lynda Carter fending off bullets with this thing?