Tazmo Develops 30lm/W Inorganic Light-emitting Diode Panel

Jan 19, 2012
Tetsuo Nozawa, Nikkei Electronics
The newly-developed inorganic light-emitting diode panel with a luminous efficiency of 30lm/W
The newly-developed inorganic light-emitting diode panel with a luminous efficiency of 30lm/W
[Click to enlarge image]
An A4-size inorganic light-emitting diode sheet made by using old technology (left) and an A4-size sheet made by using the latest technology (right). The power consumption of the latter is about half that of the former.
An A4-size inorganic light-emitting diode sheet made by using old technology (left) and an A4-size sheet made by using the latest technology (right). The power consumption of the latter is about half that of the former.
[Click to enlarge image]
An A4-size inorganic light-emitting diode panel can be easily bent.
An A4-size inorganic light-emitting diode panel can be easily bent.
[Click to enlarge image]
An A2-size panel
An A2-size panel
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Strip-shaped panels
Strip-shaped panels
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The device structure. On a PET (polyethylene terephthalate) film, a transparent electrode, fluorescent material layer, dielectric material layer and back-side electrode are formed in this order. Its thickness is about 0.3mm excluding the protection film.
The device structure. On a PET (polyethylene terephthalate) film, a transparent electrode, fluorescent material layer, dielectric material layer and back-side electrode are formed in this order. Its thickness is about 0.3mm excluding the protection film.
[Click to enlarge image]

Tazmo Co Ltd, a major LCD panel equipment manufacturer in Japan, developed an inorganic light-emitting diode panel with a luminous efficiency of 30lm/W by using coating process.

Because of its high luminous efficiency, the panel might become a dark horse in the market for flexible surface-emitting lighting devices. Tazmo developed the panel in late 2011 and exhibited it at an exhibition in Tokyo.

Inorganic light-emitting diode technologies have been lagging far behind organic light-emitting diode (OLED) technologies in terms of luminous efficiency and losing attention from players in the industry. This time, Tazmo drastically improved luminous efficiency.

On the other hand, a coating process that is necessary for making flexible OLED panels has not been commercialized yet. As for coating process, some people consider that inorganic light-emitting diodes have an advantage because they have simpler element structures. And it is possible that inorganic light-emitting diodes have actually taken a lead over OLEDs in that regard with the development of the latest panel.

"We expect that the new panel will be employed for supplemental lighting and illumination for clothes first," Tazmo President Toshio Ikeda said.

Inorganic light-emitting diode technologies use the EL (electroluminescence) phenomenon, in which light is generated by applying voltage to a thin film made of an inorganic dielectric material (or fluorescent material). The principle is different from the one for OLEDs, which, like LEDs, use the recoupling of electrons and electron holes at semiconductor pn junctions.