- What is OLED light?
- The Principles
- OLED vs LED
- OLED Display vs OLED Lighting
- Additional Resources
What is OLED light?
OLED stands for Organic Light Emitting Diode. OLED light technology, as opposed to OLED display, is primarily used for general lighting and automotive applications. It is favorable for these applications due to its homogeneous light emission and ultra-thin, lightweight form factor, among other features.
OLED technology can be used to build solid state lighting (SSL) composed of thin, carbon-based organic layers sandwiched between two electrodes. When DC current is applied, holes and electrons are injected from the anode and cathode respectively into the organic layers, forming an excited state on the organic molecules. When the excited state relaxes, electroluminescence occurs, and light is emitted.
The color or wavelength of light emitted is determined by the structure of the organic molecule that forms the excited state. A wide variety of emission colors are available with OLED technology, but for OLED lighting, the mixture of organics is carefully selected to design the resulting spectrum of white light that is emitted.
An OLED lighting panel starts with a transparent substrate, which provides mechanical structure as well as desired optical properties. The substrate includes a patterned transparent conductor layer, usually indium tin oxide (ITO), which serves as the bottom electrode or anode. Very thin layers of organic materials are deposited onto the anode surface, followed by a metallic cathode, or second electrode. The entire OLED stack is thinner than a human hair, and each layer may contain several organic materials.
Unlike inorganic LEDs, the organic materials are unordered, and do not need to form single crystals for efficient emission or be deposited on expensive crystalline substrates. Therefore, the emission area with OLED lighting can cover most of the substrate, providing a broad, low-glare lighting source with no hot spots that is ideal for large-area light sources. The wide, surface level emission of OLED lighting also provides the ability to selectively address certain areas segments of the panel with high contrast if the electrodes are patterned, which allows delivery of an additional level of communication through motion, customization, and branding with light.
The Principles of OLED Light Technology
Working with architects, designers, luminaire manufacturers, automotive customers, and a wide array of specialty product innovators I see the “why OLED?” question from many perspectives. Different benefits will be the reason for utilizing OLEDs in different applications. However, the common thread is that OLED provides a unique advantage in the design solution.
OLED light panels are ultra-thin and lightweight. They do not generate heat the way other light sources do eliminating the need for a heat sink. In fact, when attached to a driver, the OLED panel itself could essentially be considered a fixture.
OLED amber has no blue component and is excellent for nighttime circadian rhythm management and sleeping patterns. Several studies have shown that pure amber, without blue, can reduce anxiety in patients and the elderly, making it ideal for healthcare spaces.
Health and Wellbeing
Blue light hazard is a hot item these days. Exposure to high intensity blue wavelengths is linked to macular degeneration and circadian rhythm disruption depending on the time of exposure. Light sources, like fluorescent light bulbs that are bright white and cool and incandescent bulbs cause the most damage to your eyes.
OLEDs are inherently safe in the way they deliver all wavelengths of light, including blue light. OLEDs deliver the light levels you need at intensity well below any risk for damage. This is validated through the IEC standard for physiological risk of blue and infrared light –OLEDs pose no risk for skin and eyes and are rated as exempt for all photobiological risks.
Broad spectrum OLED light offers a full color palette while eliminating the negative attributes of most artificial lighting solutions, like UV, glare, shadows, and flickers. OLED’s combination of brightness with an inimitable softness enhances your environment, providing you with light that resembles daylight —even when you’re stuck inside all day.
Nearly 20 percent of all electricity worldwide is used for lighting. At the same time, the energy for lighting accounts for six percent of the world’s greenhouse gases. This is about 1.9 billion tons of carbon dioxide (CO2) or about 70 percent of emissions from all passenger cars worldwide (Source: United Nations Environment Program). By using energy-saving lighting – such as OLED lighting – these figures can be reduced significantly.
OLEDWorks panels last over 30 times longer than inefficient incandescent light bulbs. Tests have shown that OLED lighting will become about as efficient as LEDs already are. These provide up to 80 percent better efficiency, making clear the energy savings with OLED lighting compared to the traditional light bulb. In addition, the manufacturing process of this light source is very efficient – OLEDs are a sustainable light source in many ways.
OLED lights are surface light sources, making a diffuser screen, which scatters the light, unnecessary. This has a big advantage because with conventional light sources up to 70 percent of the light output is lost by the system. Not with OLED technology. Here the efficiency of the light source equals the system efficiency.
Because OLED lighting consists of almost 100 percent glass, they can easily be recycled at the end of their operating life. OLED light technology from OLEDWorks also meets the European Union’s stringent RoHS and REACH directives for hazardous materials. With OLED technology, users not only get a very attractive surface light source, but also a particularly green one. With each additional OLED lighting solution on the market, adopters are ensured a reduction in their electricity bills, and contribute to a reduction in global energy consumption for lighting.
OLED vs LED
LEDs are tiny, highly concentrated light sources, well suited for creating beams of intense light required in automotive headlamps, spotlights, flashlights and other high-intensity, focused lighting applications. To make LEDs useful for general lighting or other low intensity applications, the LED light must be diffused, spread and homogenized, lowering the energy efficiency of the ultimate delivered light.
In contrast, OLED lighting panels are inherently homogeneous and glare-free, such that the OLED lighting panel energy efficiency is the same as the delivered light efficiency. This effect is so significant that in some applications, such as automotive taillights, the OLED lighting solution is both more homogeneous and more energy efficient than the LED lighting solution.
In general lighting, it is the combination of OLED and LED lighting that will deliver the highest ultimate application specific energy efficiency. By taking advantage of the strengths of each technology, the lowest energy consumption and most human-centric lighting solutions can be achieved.
OLED Display vs OLED Lighting
Both OLED display and OLED lighting are based on the same solid-state physics principles. Simply put, OLED technology is comprised of organic semiconductor materials that emit light when electrically energized. The OLED materials emit all wavelengths of interest directly and do not need a phosphor conversion to achieve the desired spectrum.
OLED’s unique light quality serves both applications superbly. For lighting, the naturally diffuse output positions OLED fixtures as the glare-free, full color experience that is highly desired for visual comfort. For display, the direct color emission allows for a high color gamut including true black.
As a functional light source, OLEDs operate as a uniform, high brightness, white spectrum, large area surface light engine. The lifetime demand for lighting is very long, usually exceeding 10 years. OLED lights meet these demands extremely well. Displays, in comparison, are usually a fraction of the brightness and operate as red, green, blue (RGB) individually addressed pixels which have lower demand on lifetime. Displays transmit images, videos, and messaging – usually at very high image data rates (>120Hz). Lights provide functional illumination, ambiance, and, at times, communication.