OLED stands for Organic Light Emitting Diode. OLED light technology, unlike OLED displays, is mainly used for general lighting and automotive applications. For these applications, it is favorable due to its homogeneous light emission and ultra-thin, lightweight form factor, among other things.
OLED technology can be used to build Solid-State Lighting (SSL), which consists of thin carbon-based organic layers sandwiched between two electrodes. When direct current is applied, holes and electrons are injected into the organic layers from the anode and cathode, respectively, forming an excited state on the organic molecules. When the excited state relaxes, electroluminescence occurs and light is emitted.
The color or wavelength of the emitted light is determined by the structure of the organic molecule that forms the excited state. In OLED technology, a variety of emission colors are available, but for OLED lighting, the mixture of organics is carefully selected to shape the resulting spectrum of emitted white light.
An OLED lighting panel starts with a transparent substrate that provides both the mechanical structure and the desired optical properties. The substrate contains a patterned transparent conductive layer, usually indium tin oxide (ITO), which serves as the bottom electrode or anode. Very thin layers of organic materials are deposited on the anode surface, followed by a metallic cathode or second electrode. The entire OLED stack is thinner than a human hair and each layer can contain several organic materials.
與無機 LED 不同，有機材料是無序的，不需要形成單晶或沉積在昂貴的晶體基板上以實現高效發射。因此，OLED 照明的發光區域可以覆蓋絕大部分基板，并提供廣角、低眩光、無熱點的光源，是理想的大面積光源。當電極被圖案化時，OLED 照明寬廣而平坦的光發射還具備選擇性地瞄準具有高對比度的面板特定區域的能力，通過移動、定制和品牌化提供額外的交流層。
Unlike inorganic LEDs, the organic materials are disordered and do not need to form single crystals or be deposited on expensive crystalline substrates for efficient emission. Therefore, the emission area with OLED lighting can cover most of the substrate and provides a wide, low glare light source with no hot spots, ideal for large area light sources. The wide, flat emission of OLED lighting also offers the ability to selectively target specific areas of the panel with high contrast when the electrodes are patterned, providing an additional layer of communication through movement, customization and branding with light.
Some advantages of OLEDs
# OLED 與 LED
OLED vs LED
LED 是微型、高度集中的光源，適用于生產汽車前燈、前照燈、手電筒和其他高強度、聚焦照明應用所需的強光束。為了使 LED 可用于汽車內飾照明或其他低強度領域，LED 光必須被漫射、散射和均勻化，最終降低所傳遞的發光能效。
相比之下，OLED 發光面板本質上是均勻且無眩光的，因此 OLED 發光面板的能效與提供的光效率相匹配。這種影響非常顯著，以至于在某些應用中，OLED 照明解決方案比 LED 照明解決方案更均勻、更節能。
LEDs are tiny, highly concentrated light sources thatare suited for producing intense beams of light required in car headlights,headlamps, torches and other high-intensity, focused lighting applications. Tomake LEDs useful for automotive interior lighting or other low-intensityapplications, the LED light must be diffused, scattered and homogenized, whichreduces the energy efficiency of the light ultimately delivered.
In contrast, OLED light panels are inherentlyhomogeneous and glare-free, so the energy efficiency of OLED light panelsmatches the light efficiency delivered. This effect is so significant that insome applications, the OLED lighting solution is both more homogeneous and moreenergy efficient than the LED lighting solution.
Both the OLED display and OLED lighting are based on the same principles of solid-state physics. OLED technology consists of organic semiconductor materials that emit light when electrically energized. The OLED materials emit all wavelengths directly and do not require phosphor conversion to achieve the desired spectrum.
The light quality of OLED fulfils both applications. For illumination, the naturally diffuse light beam positions OLED luminaires as a glare-free full color experience for visual comfort. For display, the direct color output enables a high color gamut including true black.
As a functional light source, OLEDs work as a uniform, large area, high brightness, white spectrum light engine. The service life of the lighting usually exceeds 10 years. Displays, by comparison, typically have a fraction of the brightness and operate as individually addressed red, green, blue (RGB) pixels that have a shorter life. Displays transmit images, videos and messages - usually at very high image data rates (>120Hz).
Summary of the differences between OLED display and illumination
OLED luminaires are optimized for illumination, unlike OLED displays, so OLED luminaires are much brighter than OLED displays (8,000 nits for OLED luminaires compared to less than 1,000 nits for OLED displays). OLED luminaires also have a much longer lifetime than OLED displays. OLED lighting drops to 70% of initial brightness at over 100,000 hours of continuous use compared to OLED displays, which drop from a much lower initial brightness to 50% over the same period.
Finally, OLED luminaires are designed and manufactured to be cost effective, with OLED lighting panels being more like an incandescent bulb than the high-end price of an OLED display. The OLED display's high frame rate capability makes it ideal for displaying images, videos and messages via phone screens and televisions.
Exposure to high-intensity blue wavelengths is associated with macular degeneration and circadian rhythm disturbances, depending on the exposure time. Light sources such as fluorescent lamps, which are bright white and cool, and incandescent bulbs have a higher risk for damaging to your eyes.
OLEDs are inherently safe because they deliver all wavelengths of light, including blue light. OLEDs deliver the light levels you need at an intensity far below the risk of damage. This is validated by the IEC standard for the physiological risk of blue and infrared light - OLEDs pose no risk to skin or eyes and are considered free of all photobiological risks.
Wide-spectrum OLED light provides a full color palette while eliminating the negative characteristics of most artificial lighting solutions such as UV, glare, shadow and flicker. OLED's combination of brightness and inimitable softness enhances the environment and provides with daylight-like light - even if you sit indoors all day.
Almost 20 percent of the world's electricity is used for lighting. Energy for lighting accounts for six percent of global greenhouse gases. That is about 1.9 billion tons of CO2 or about 70 percent of the emissions of all passenger cars worldwide (source: United Nations Environment Program). By using energy-saving lighting - such as OLED lighting - these values can be significantly reduced. Tests have shown that OLED lighting becomes about as efficient as LEDs already are. These provide up to 80 percent better efficiency, illustrating the energy savings with OLED lighting compared to traditional incandescent bulbs. In addition, the manufacturing process of this light source is very efficient.
OLED luminaires are surfacelight sources that eliminate the need for a diffuser screen that diffuses thelight. This has a major advantage, because with conventional light sources up to70 percent of the light output is lost through the system. With OLED lighting technology,the efficiency of the light source is equal to the system efficiency.Additionally, OLED lighting is almost 100 percent glass, that can be easilyrecycled at the end of its life.
The service life of OLEDs is temperature-dependent: A well-cooled OLED (of any color) with a low initial luminosity always has a longer life than an OLED that is operated at maximum luminosity from the start without cooling. This is due to diffusion processes in the OLED that occur more quickly at higher temperatures.
Another disadvantage of OLEDs is the lower luminous efficacy in the range of 40 lm/W to 60 lm/W of commercially available OLEDs compared to light-emitting diodes. Peak values of selected laboratory samples of OLEDs achieve values just above 100 lm/W. Light-emitting diodes achieve laboratory values of 200 lm/W.
In addition to shorter life and lower luminous efficacy, OLEDs also react sensitively to certain external substances. In addition to water, which is omnipresent due to humidity, penetrating oxygen can also destroy the organic material. It is therefore important to hermetically encapsulate the display and protect it from external influences. The necessary rigid encapsulation impairs flexibility. The highly reactive injection layer of calcium and barium is especially endangered by corrosion with oxygen. Typical signs of failure are circular, growing non-luminous areas, so-called "dark spots". The cause is often particle contamination during vapor deposition of the metal layers. The microscopic edges of the multilayer structure are also infiltrated by corrosion, which leads to a decrease in the effective luminous pixel area in screen applications.