OLED and LED light-emitting principle of the difference

Today, LED market has been saturated, the price war intensified, profit margins continue to be compressed. In this context, OLED should be born from time to time, for the majority of businesses to open up new markets provide a broad prospect, then the distinction between OLED and LED in the end where their light-emitting principle is what, let's explore together

 

LED is a metal material, and oled with the organic material, the two principles of light is the same, the difference is that oled do not need backlighting itself will be light, is the use of light-emitting diode array composed of brightness than LED LCD high , The thickness of the thinner, is the future of LED LCD screen alternatives.LED LCD screen needs backlight, brightness in general, in the sunlight display low, but is currently the most widely used.

 

LED applications can be divided into two categories: First, LED single tube applications, including the backlight LED, infrared LED, etc .; the other is the LED display, at present, China in the LED basic materials manufacturing and international there are still some gaps, but On the LED display, the Chinese design and production technology level with the international basic synchronization.

 

LED display is composed of light-emitting diode array of a display device. It uses low voltage scanning drive, with: low power consumption, long life, low cost, high brightness, less failure, viewing angle, visual distance and so on.

 

OLED: Organic Light Emitting Display, organic light-emitting display, in the mobile phone LCD is a new type of rise, known as the "dream display." OLED display technology and traditional LCD display different, no backlight, using a very thin coating of organic materials and glass substrates, or special will use plastic substrates, when there is current through, these organic materials will be light. And OLED display screen can be made lighter and thinner, greater viewing angle, and can significantly save energy. However, although the future of better technology will replace the TFT OLED and other LCD, but the organic light-emitting display technology also has short life, the screen is large and difficult to defect.

 

OLED: also known as organic EL display, organic light-emitting diodes (Organic Light-Emitting Diode).

 

The basic structure of an OLED consists of a thin, transparent semiconductor indium tin oxide (ITO), which is connected to the positive side of the power supply, plus another metal cathode, which is packaged into a sandwich structure. The entire structure layer includes a hole transport layer (HTL), a light emitting layer (EL) and an electron transport layer (ETL). When the power supply to the appropriate voltage, the cathode hole and cathode charge will be combined in the luminous layer, resulting in light, according to their different formulations produce red, green and blue RGB primary colors constitute the basic colors. OLED features are their own light, unlike TFTLCD need to backlight, so the visibility and brightness are high, followed by low voltage requirements and high power efficiency, coupled with fast response, light weight, thin thickness, simple structure, low cost , Is considered one of the most promising products of the 21st century.

 

Organic light-emitting diodes and light-emitting principle similar to the inorganic light-emitting diodes. When an element is subjected to a forward bias (DC), the voltage and energy drive the electron and the hole, respectively, from the cathode to the anode. When the elements meet in conduction , To form so-called electron-hole recombination (Electron-Hole Capture). When the chemical molecules are excited by external energy, if the electron spin (ElectronSpin) and the ground state electron pairs, singlet (Singlet), the release of the so-called fluorescence fluorescence (Fluorescence); the other hand, if the excited state Electrons and ground state electron spin unpaired and parallel, is called triplet (Triplet), the release of the light for the so-called phosphorescence (Phosphorescence).

 

When the state position of the electron is returned from the excited high energy level to the steady state low energy level, the energy of the electron will be released in the form of light emission or heat dissipation, respectively, in which the photon portion can be used as a display function; However, the organic fluorescent material can not observe triplet phosphorescence at room temperature, so the theoretical limit of luminous efficiency of PM-OLED is only 25%.

 

PM-OLED light-emitting principle is the use of materials to the energy difference, the energy released into the photon, so we can choose the appropriate material as a light-emitting layer or in the light-emitting layer doped with dyes to get the light we need color. In addition, the combination of electrons and holes in the general reaction in tens of nanoseconds (ns), so the PM-OLED response speed is very fast.

 

Typical structure of P.S.:PM-OLED. A typical PM-OLED consists of a glass substrate, ITO (indium tin oxide) anode (Anode), an organic light emitting layer (Emitting Material Layer) and a cathode (Cathode), etc., in which thin and transparent ITO anode and metal The cathode is sandwiched with the organic light-emitting layer as a sandwich, and the organic material is excited to emit light when a voltage (Hole) injected into the anode is combined with an electron (Electron) from the cathode in the organic light-emitting layer.

 

(HIL), hole transport layer (HIL), hole transport layer (HIL), and hole transport layer (HIL), which are commonly used in multi-layer PM-OLED structures, (ETL) and an electron injection layer (EIL), and an insulating layer is required to be provided between each transport layer and the electrode, so that the vapor deposition (Evaporate) ) Processing is relatively difficult to improve, the production process has become complicated.

 

Since organic materials and metals are very sensitive to oxygen and water vapor, after the completion of production, subject to packaging protection. Although the thickness of organic thin film layer is about 1,000 ~ 1,500A ° (0.10 ~ 0.15um), the total thickness of the whole panel is less than 200um after encapsulation and desiccant. (2mm), with the advantage of light.

 

The future, OLED indoor lighting to replace LED is a historical necessity, and this piece of cake will have more manufacturers to split.

 

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