We often see LCD, LED, OLED, QLED , although there is only one letter difference, but the difference is very big! I will explain it in detail here today.

LCD is the full name of Liquid Crystal Display , mainly including TFT, UFB, TFD, STN and other types of liquid crystal display.

The LCD structure is to place a liquid crystal cell between two parallel glass substrates. The lower substrate glass is equipped with TFT (thin film transistor), and the upper substrate glass is equipped with a color filter. The liquid crystal molecules are controlled by the signal and voltage changes on the TFT. Rotate the direction, so as to achieve the display purpose by controlling whether the polarized light of each pixel point is emitted or not.

LCD is a substance between solid and liquid. It cannot emit light by itself and requires additional light sources. Therefore, the number of lamps is related to the brightness of the liquid crystal display.

LED (Light-emitting diode) light-emitting diode screens, in fact, the images of these displays are still produced by liquid crystals. Light-emitting diodes are only used as light sources. Technically, they are still LCD displays, or LED-backlit LCD TVs.

LCD TV with LED screen has the advantages of small size, low power consumption, long life, low cost, high brightness, long viewing angle and high refresh rate. The disadvantage is that the color performance is relatively poor, especially when the LCD screen is folded. The color deviation is more obvious in the place.

OLED (Organic Light-Emitting Diode) Organic Light-Emitting Diode, although there is only one letter difference between it and LED, in fact the two describe completely different things.

We all know that the liquid crystal panel emits light through the backlight, which produces a variety of different colors through the refraction of the liquid crystal molecules. The liquid crystal molecules themselves cannot emit light, and the LED only refers to the backlight.

The OLED can emit light by itself, so there is no need for a backlight. LED uses metal materials, while OLED uses organic materials. It can emit light without being illuminated by lights, and the contrast is better. Normally, LEDs need to be illuminated by backlights to see things.

At present, the materials used in light-emitting diodes are all inorganic semiconductor materials, which are difficult to apply to large areas and require high-resolution components (EX: screens). To solve these problems, new organic semiconductor materials (that is, those containing hydrocarbons) are required. Material), coating it on a conductive glass sheet, and passing an electric current, it can emit light of various different wavelengths.

QLED is the abbreviation of Quantum Dot Light Emitting Diodes, which is a self-luminous technology that does not require additional light sources.

Quantum Dots are extremely tiny semiconductor nanocrystals that are invisible to the naked eye. They are particles with a particle size of less than 10 nanometers. Quantum dots have a unique characteristic: whenever they are stimulated by light or electricity, they will emit colored light. The color of the light is determined by the material and size of the quantum dot, and its frequency can be changed by changing the size of the quantum dot. , Shape and material to accurately adjust, so as to achieve a variety of applications.

The structure of QLED is very similar to OLED technology, the main difference is that the light-emitting center of QLED is composed of quantum dots. Its structure is that electrons and holes on both sides converge in the quantum dot layer to form photons (Exciton), and emit light through the recombination of photons.