OLED (Organic Light-Emitting Diode, organic light-emitting diode) is a special type of light-emitting diode, and its working principle and structure are different from those of traditional leds. The following is a detailed introduction to the working principle and structure of OLED:

1. Structure
    OLED is usually composed of the following main layers:
    Substrate: The substrate is the bottom layer of an OLED panel, usually made of glass or plastic, providing support and structural support.
    Anode: The anode is a layer located on the substrate, usually composed of transparent conductive materials such as indium tin oxide (ITO), and is used to inject positive charges.
    Organic Emission Layer: This is the part of OLED, including organic materials that emit light. Organic light-emitting layers can be classified according to different types of OLeds as:
    Small Molecule OLED: Volatile organic small molecule materials are usually used, and a uniform film is formed through vacuum evaporation technology.
    Polymer OLED: It uses polymer organic materials and is usually formed into films through solution processing technology.
    Cathode (Cathode) : The cathode is an electrode located above the organic light-emitting layer, usually made of reflective metals such as aluminum, calcium, etc. The cathode is mainly responsible for injecting electrons.

2. Working principle
    The light-emitting process of OLED involves the recombination of electrons and holes (positive charges) and the excitation of light-emitting materials in the organic light-emitting layer. Its working principle is as follows:
    When an external voltage is applied between the anode and cathode of an OLED, positive charges (holes) are injected into the anode, while electrons are injected into the cathode.
    When positive charges and electrons encounter each other within the organic light-emitting layer, recombination occurs, releasing energy.
    This energy release excites the luminescent materials in the organic luminescent layer, causing them to emit photons.
    The emitted photons are emitted through a transparent anode, forming visible light.

3. Characteristics and advantages
    OLED technology has significant advantages over traditional LCD display technology:
    Spontaneous luminescence: OLED is a self-luminous technology that does not require a backlight, thus enabling higher contrast and deeper blacks.
    Ultra-thin and flexible: OLED panels can be made extremely thin and flexible, making them suitable for applications in curved and curled display devices.
    Fast response speed: OLED has an extremely fast response speed and is suitable for applications with high-speed image changes, such as gaming and video.
    Energy conservation and environmental protection: OLED can completely turn off the relevant pixels when displaying black, achieving significant energy-saving effects, and the organic materials are relatively environmentally friendly.