Common features of LED and OLED
Difference between LED and OLED
LED and OLED are two major display technologies in the market today. Both of them are technologies that convert electrical energy into visible light through the process of electroluminescence. They have been applied to a variety of display technologies, but their application in TV displays is the most well-known.
Light-emitting diodes (LEDs) and their organic counterparts, organic light-emitting diodes (OLEDs), are more reliable than traditional incandescent lamps. In addition, they do not generate heat when they emit light, while incandescent lamps emit white-hot light from heated filaments.
It should be noted that the emergence of OLED is based on existing LED technology and requires special equipment such as glove boxes and spin coaters for precise manufacturing.
Although OLEDs are superior in many aspects such as fast response and contrast, they cannot completely replace LEDs. As a more mature technology, LEDs also have their irreplaceable advantages, such as relatively low cost and long life.
LED and OLED coexist as two display technologies, and play their respective advantages in different application scenarios. Therefore, it is very necessary for us to understand the working principles of LED and OLED, as well as the differences between them and their respective pros and cons.
Kinglight LED, born for excellent display
LEDs are made of semiconductor materials, usually formed into a diode with a p-n junction. This means it includes a “p-type” material (with an excess of positive charge carriers, called holes) and an “n-type” material (with an excess of negative charge carriers, called electrons). At the junction where these two materials meet, a neutrally charged region forms, called the depletion region.
When current is applied to the LED, electrons move from the n-type material to the p-type material, while holes move in the opposite direction. When the electrons and holes reach the p-n junction, they interact. This interaction causes the electrons to lose energy. This energy is released in the form of photons (light particles).
The lost energy determines the color of the light; different semiconductor materials emit different colors of light. For example, indium gallium nitride can produce blue and green light, while aluminum gallium indium phosphide can produce red, yellow, and orange light.
Structure of Basic LED P-N Conjunction
OLEDs consist of multiple layers, including an anode, cathode, and an organic layer between them. The term “organic” refers to organic molecules, i.e., hydrogen and carbon. Within the organic layer are an emissive layer (EML) and a conductive layer (CTL).
When an electric current is applied, the anode (positive) layer attracts electrons (negative charge) from the cathode, which introduces electrons into the organic layer.
Electrons move from the cathode through the organic layers to the anode, causing electrons within the organic material to become “excited.” This means that the electrons move to a higher energy level within the molecules in the organic layer. When these excited electrons return to their normal state, they release energy in the form of light.
The color of the emission depends on the type of organic molecules in the emissive layer. By combining different organic compounds, OLEDs can produce a wide spectrum of colors for full-color displays, including red, green, and blue.
The emissive layer is the most important component of an OLED, and much research has focused on how to improve this critical material structure.
Both LED and OLED technologies are known for their energy efficiency, using less electricity to produce more light than traditional incandescent or fluorescent lamps.
Both LEDs and OLEDs create a wide range of colors, making them ideal for high-quality displays and lighting.
LEDs and OLEDs are more environmentally friendly than traditional lighting because they contain fewer harmful substances, such as mercury in fluorescent lamps.
Due to their small size, high efficiency and superior light quality, their versatility allows them to be used in a variety of applications, from small device screens to a wide range of lighting systems.
Both LEDs and OLEDs last much longer than standard incandescent and fluorescent light sources. Of course, OLEDs may not last as long as traditional LEDs.
Traditional LEDs use inorganic light-emitting materials, while OLEDs use organic molecules. Different materials have different advantages.
LED is widely used due to its energy saving and long life, but it also has some inherent disadvantages compared with OLED. Therefore, when choosing LED or OLED products, we need to fully understand the advantages and disadvantages of LED.
Longer life and reliability
LEDs have a longer lifespan and are less prone to problems such as screen burn-in (a phenomenon where an image remains permanently on the screen).
Higher cost-effectiveness
LED technology is generally less expensive than OLED, making LED displays more affordable.
Higher Brightness
LED displays can generally reach higher brightness levels than OLEDs. This makes them ideal for use in brightly lit environments.
Reduced color and contrast
Compared with OLED, the contrast and color rendering of LED screens are relatively low.
Thicker and less flexible
Generally speaking, LED screens are thicker than OLED screens. In addition, LED screens cannot achieve the same flexibility as OLED screens.
OLED is known for its vivid colors and extreme black effects. OLED also has its own unique advantages and disadvantages. Understanding these advantages and disadvantages will help us make choices that better suit our needs when purchasing devices such as TVs and smartphones.
Thinner and flexible
OLEDs are thinner than LEDs and can be made into foldable or rollable displays using flexible materials.
More accurate colors and higher contrast
Individual OLED pixels can emit their own light, improving color and contrast control. When the pixel is turned off, OLED can achieve true black.
Faster response
Compared with LED, OLED can provide a faster response. Therefore, OLED screens often have a higher refresh rate, which can effectively reduce the image blur that may occur when playing high-dynamic image content, thereby achieving a smoother transition.
Higher Costs
The cost of manufacturing OLED displays is higher than that of manufacturing LED screens. This is a factor that we must consider when choosing between LED screens and OLED screens.
Shorter lifespan
OLEDs have a shorter lifespan than LED displays. The organic materials used in OLEDs degrade over time, causing color and brightness issues.
In conclusion, LED and OLED, as two popular display technologies, both have more accurate color rendering and better display effects, but they also have their own pros and cons.
LED not only has a long service life, but also has a relatively lower cost, and is more suitable for large screens, such as the construction of large format LED screens; while OLED excels in fast response, color and extreme black, but its cost is relatively higher and its service life is short, and it is mainly suitable for high-end displays, such as OLED TVs and smartphone screens.
