Bayer MaterialScience, Osram Jointly Develop Light Extraction Film for OLED Surface-Emitting Panels

Thanks to their low energy consumption, long service life and high-quality light, organic light-emitting diodes, or OLEDs for short, are being proclaimed as the light source of the future. Working in partnership with Osram, Bayer MaterialScience has now developed Makrofol TP 228, a highly efficient, polycarbonate-based light extraction film that is being used in the first OLED surface-emitting panel to be sold on a broad commercial basis – the Orbeos from Osram.

“As a light extraction layer just 100 µm thick, the film increases light yield by between 40 and 60 percent by reducing the total light reflection in the OLED lamp,” said Dr. Heinz Pudleiner, product developer for polycarbonate films in the Functional Films section at Bayer MaterialScience. As a result of this high light yield, the surface-emitting panel can operate on a lower electrical voltage, which extends its service life. The new film also maintains the consistency of the color impression and ensures that it looks the same regardless of the angle from which it is viewed.

The extraction film is bonded to the glass surface of the OLED system. Its light-boosting effect is based on a very fine structure embossed onto the film surface and ultra-pure light-scattering particles that are incorporated into the film as additives.

The octahedron-shaped surface-emitting panel, recently unveiled by Osram at the Light+Building 2010 trade show in Frankfurt, Germany, has a round lamp surface with a diameter of 80 millimeters. Only 2.1 millimeters thick, it also weighs only 24 grams. It contains no mercury and emits a warm, glare-free white light with no infrared radiation and features an infinitely-regulated dimming function. Furthermore, it significantly outperforms traditional halogen lamps, delivering typical brightness levels of 1000 cd/m2 with power consumption of less than one watt. Under optimum conditions, the new system can achieve a service life of over 5,000 hours.

The individual panels can easily be assembled using spring contacts to form illuminated areas such as lit ceilings, wallpaper and room dividers, creating lighting effects that are both atmospheric and functional. As a result, they are ideal for premium applications in museums, hotels, restaurants, offices, private rooms, shops and trade shows, for example.

“Our customer service provided Osram with comprehensive support for the development of the OLED light. Osram also benefited from our development and production know-how in the area of films,” said Pudleiner.

OLED light extraction films represent just one part of the broad film portfolio that Functional Films has built up for lighting and lamp applications. They are a type of light diffusing film, a product category that has major application potential in the production of LEDs and flexible displays. As a result, light diffusion films are a key focal point of development work at Functional Films.

“For example, we are working on film grades that are treated with an anti-dust protective coating, or can be produced in a range of colors. In principle, all our films for light applications can be printed, formed and back-injected using the Film Insert Molding (FIM) process,” added Pudleiner.