The LCD is constructed by placing a liquid crystal cell between two parallel glass substrates, a TFT (thin film transistor) is arranged on the lower substrate glass, and a color filter is arranged on the upper substrate glass, the direction of rotation of Liquid Crystal Molecule is controlled by the change of signal and voltage on TFT, so that the output of polarized light at each pixel can be controlled.

LCD is a solid state and liquid between the material, itself is not luminous, with the need for additional light source. Therefore, the number of light liquid crystal display is related to the brightness of the lamp.

Led (Light-emitting Diode) Light-emitting diode screens. In fact, the images of these displays are still produced using liquid crystal (LCD) Light-emitting Diode as light source. They are still technically 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, far viewing angle and high refresh rate, especially in the LCD screen where the fold color deviation is more obvious.

Oled (Organic Light-Emitting Diode) Organic Light-Emitting Diode. It's just a letter away from an LED, but it actually describes something completely different.

We all know that LCD panels emit light from a backlight, and that they produce different colors through the refraction of liquid crystal molecules, which themselves do not emit light, while leds refer only to the backlight.

An OLED, on the other hand, emits its own light, so there is no need for a backlight. Leds are made of metal, while OLED is made of organic material. It emits its own light without lighting. The contrast is better. leds need backlights to see. The materials used in the current light-emitting diode are inorganic List of semiconductor materials, which are difficult to apply to large-scale components requiring high resolution (EX: screens) , the solution to these problems lies in new Organic semiconductor materials -- that is, hydrocarbon-containing materials -- that can be coated on electrically conductive glass sheets and, by passing an electric current through them, emit light at a variety of wavelengths.

QLED, short for Quantum Dot Light Emitting Diodes, is a self-Emitting technology that requires no additional Light source. QUANTUM DOTS are tiny semiconductor nanocrystals that are invisible to the naked eye. They are particles less than 10 nanometers in size. QUANTUM DOTS have an unusual property: whenever stimulated by light or electricity, they emit colored light, which is determined by the material and size of the dots, its frequency can be precisely adjusted by changing the size, shape, and material of the quantum dots for a variety of applications.

The structure of QLED is very similar to that of OLED technology, but the main difference is that QLED's light-emitting centers are made of Quantum dots. The structure is that the two-side Electron (Electron) and Hole (Hole) converge in the quantum dot layer to form photon (Exciton) and emit light through Photon recombination.