OLED Lighting
General FAQ
- How do OLEDs differ from LEDs?
- What applications do you envisage for OLEDs?
- What are the differences between OLEDs and other light sources?
- What is special about OLEDs? What can they do that other light sources cannot?
- Which applications have already been covered?
- Which market segments will OLEDs enter?
How do OLEDs differ from LEDs?
Question
How do OLEDs differ from LEDs?
Answer
In contrast to traditional point-like inorganic light emitting diodes (LEDs) that are based on complex crystalline structures, OLEDs are flat light sources that use organic semiconductors to generate light. They consist of a (glass) substrate, a transparent electrode, one or more thin organic layers, a counter-electrode which can also be transparent. The component is encapsulated to protect against oxidation and moisture. An OLED operates on the principle of injection electro-luminescence, just like an inorganic LED. Positive and negative charge carriers are made to give off light by recombining in an emission layer. In other words, light is emitted in a semiconductor – an inorganic semiconductor in the case of an LED and an organic one in the case of an OLED. The structure of the molecules determines the color of the light; in the case of LEDs the light color is determined by the crystal structure of the semiconductor materials.
What applications do you envisage for OLEDs?
Question
What applications do you envisage for OLEDs?
Answer
OLEDs with their special properties (two-dimensional light source, transparent, ultra low profile, potentially flexible) are opening up new applications such as light tiles, light partition walls, and transparent light sources that emit light only after dusk and act as windows during the day. OLEDs can also be integrated in kitchen and bathroom installations for example to create revolutionary lighting designs. The greatest successes are expected in applications in which the unique features of OLEDs are used to greatest effect, for example in extremely thin, efficient and transparent two-dimensional light sources with excellent quality of light.
What are the differences between OLEDs and other light sources?
Question
What are the differences between OLEDs and other light sources?
Answer
The active, organic and mostly transparent layers of OLEDs are extremely thin, measuring less than 500 nm. This makes the complete OLED itself extremely flat, lightweight and potentially flexible. The lighting system can therefore be ultra low-profile, transparent and flexible and can cover a large area. Current limitations in terms of flexibility and an extremely flat design are the rigid glass substrate and the type of encapsulation. Thinner and more flexible substrates, thin-film encapsulation and transparent electrode material would further enhance the special properties of OLEDs, such as extreme flatness, flexibility and transparency. With their diffused light, OLEDs are suitable for scaling up to large areas. The result is a new type of flat light source that is very different from any previous light source.
OLEDs are complementary to most existing light sources and will open up entirely new areas of application and growth markets. They are already inspiring designers and will be enriching the market for premium designer luminaires in the near future. At a later date we expect to see revolutionary changes to the entire lighting market.
What is special about OLEDs? What can they do that other light sources cannot?
Question
What is special about OLEDs? What can they do that other light sources cannot?
Answer
OLED stands for Organic Light Emitting Diode and is a completely new technology. It is a two-dimensional light source that provides a soft light that is largely glare-free with no harsh shadows. It is possible to look directly at OLED light sources without being dazzled – in complete contrast to conventional light sources such as incandescent lamps, halogen lamps and LEDs. OLEDs are extremely thin. Their active layers have an overall thickness of less than 500 nm, which is 100 times thinner than a human hair. The total thickness of the component is typically 1.8 mm, comprising the glass substrate and the encapsulation. And even this can be reduced considerably by using thinner and more flexible substrates and thin-film encapsulation. OLED panels therefore weigh very little indeed.
White OLEDs with their broadband emission spectrum produce lighting of high quality with excellent color rendering (CRI of 80 or more). OLEDs can be easily dimmed to any level by changing the operating current. In contrast to tubular and compact fluorescent lamps they emit their full output as such as they are switched on.
OLEDs are more than just light sources, they are design elements. Even when they are switched off they look very different from conventional light sources. They are very thin, very flat, very lightweight and therefore very attractive. They can also be transparent, diffused or mirrored so they offer a completely new look. Luminaire designers can therefore look forward to enormous freedom.
Which applications have already been covered?
Question
Which applications have already been covered?
Answer
In the premium design segment OSRAM has produced initial applications in cooperation with Ingo Maurer. This world-famous lighting designer presented a spectacular work of art at Light and Building 2008 and limited edition table lights equipped with OLEDs that caused quite a sensation. These high-quality lights are primarily intended however as works of art.
Which market segments will OLEDs enter?
Question
Which market segments will OLEDs enter?
Answer
The special properties of organic light emitting diodes will be the unstoppable driving forces behind the transition from the first phase of purely emotional lighting to the second phase of functional light sources for the premium design sector. This includes the possibility of producing transparent OLEDs and precisely defining the direction in which light is emitted and the amount of light emitted. At the same time, the efficiency and brightness of the light will be improve at a rapid rate, coupled with optimized production processes that will lead to higher production volumes.
Entirely new lighting applications may be developed with effects that we can now only imagine. In the general illumination sector, one of these innovative applications could be transparent (roof) windows. By day the windows would allow natural light through, and by night they would provide light themselves, eliminating the unattractive sight of the windows becoming nothing more than dark patches. At present, attention has not yet turned to automotive applications. In particular the very high thermal stability required cannot be fully achieved at present by OLEDs. Products are not expected here until 2013 at the earliest.
OSRAM considers the ultimate development goal for OLED light sources to be volume business in the general lighting sector. This third mass market phase will start as soon as OLEDs can be manufactured in very high quantities and with consistently high quality and appropriate demand has built up on the world market. OLED Lighting is part of OSRAM’s research and development program that aims to produce efficient high-quality high-performance light sources in accordance with sustainability requirements. As economical and ecological light sources, OLEDs will enrich the broad spectrum of general lighting products and make attractive additions to the lighting portfolio.