Writer: adminRelease Time: 2024-11-27 06:28Browse: 34
OLED (Organic Light Emitting Diode) is a self-luminous display technology without backlight and liquid crystal. The following is a detailed explanation of OLED and its working principle:
OLED, the full name is Organic Light-Emitting Diode, that is, organic light-emitting diode. It is a device that uses a multi-layer organic thin film structure to generate electroluminescence. OLED is composed of a very thin coating of organic materials and a glass substrate (or a flexible organic substrate). These organic materials are driven by an electric field and emit light through carrier injection and recombination.
The working principle of OLED is mainly based on the luminescence phenomenon of organic semiconductor materials and luminescent materials under the action of an electric field. Specifically, the luminescence process of OLED can be divided into the following steps:
Carrier injection: Under the action of the electric field, the holes generated by the anode and the electrons generated by the cathode are injected into the hole transport layer and the electron transport layer respectively.
Carrier transport: The injected electrons and holes pass through the electron transport layer and the hole transport layer respectively and migrate to the light-emitting layer.
Carrier recombination and exciton formation: In the light-emitting layer, electrons and holes meet and recombine to form excitons.
Exciton de-excitation luminescence: Excitons release energy through radiation relaxation, excite luminescent molecules, and ultimately produce visible light.
OLEDs can be divided into small molecule OLEDs and polymer OLEDs (also known as PLEDs) according to the luminescent materials. In addition, OLEDs can also be divided into passive matrix display (PM-OLED) and active matrix display (AM-OLED) according to the driving mode.
PM-OLED: ITO glass and metal electrodes are parallel electrode strips, which are orthogonal to each other and form light-emitting diodes (LEDs) at the intersection. Since the display time of each row is very short, to achieve normal image brightness, the brightness of each row of LEDs must be high enough, so high current and voltage are required, power consumption is large, and display efficiency is low.
AM-OLED: Using a thin film transistor array (i.e., TFT array), CMOS polysilicon (TFT) is first made on a glass substrate, and the light-emitting layer is made on top of the TFT. The driving circuit provides a controlled current to drive the OLED, and continues to provide current after addressing to ensure that each pixel continues to emit light. Each pixel of AM-OLED emits light at the same time, with low power consumption, suitable for large-area image display.
Excellent color saturation and contrast: OLED can display richer colors and higher contrast.
Fast response speed: OLED has a very short response time and can display smoother pictures.
Light and thin and flexible: OLED is thinner and lighter, and can achieve a variety of designs, including flexible displays.
Low power consumption: OLED consumes almost no energy when displaying black, so the overall power consumption is low.
In summary, OLED is an advanced display technology with excellent color saturation, contrast, response speed, lightness and flexibility. Its working principle is based on the luminescence phenomenon of organic semiconductor materials and luminescent materials under the action of electric field, and the display function is realized through steps such as carrier injection, transmission, recombination and exciton de-excitation luminescence.
