Guide to choosing display modules: What are the differences between LCD, OLED, QLED, miniLED, and microLED?

LCD

LCD is the full name of Liquid Crystal Display, which mainly includes TFT, UFB, TFD, STN and other types of LCD screens.

LCD is constructed by placing a liquid crystal box between two parallel glass substrates, with TFT (thin film transistor) set on the lower substrate glass and color filter set on the upper substrate glass. The signal and voltage on the TFT are changed to control the rotation direction of the liquid crystal molecules, so as to control whether the polarized light of each pixel is emitted or not to achieve the display purpose.

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

LED

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

The advantages of LCD TV with LED screen are 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 the color deviation is more obvious in the folded part of the LCD screen.

OLED

OLED (Organic Light-Emitting Diode) is an organic light-emitting diode. Although it is only one letter different from LED, the two actually describe completely different things.

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

OLED can emit light by itself, so it does not need a backlight source. LED uses metal materials, while OLED uses organic materials. It can emit light independently without light exposure, and the contrast is better. The LED used in normal use needs a backlight to see things.

At present, the materials used in light-emitting diodes are all inorganic semiconductor materials, which are difficult to apply to large-area components that require high resolution (EX: screens). To solve these problems, new organic semiconductor materials (i.e. materials containing hydrocarbons) are applied on conductive glass sheets and passed through current to emit light of various wavelengths.

QLED

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 stimulated by light or electricity, quantum dots will emit colored light. The color of the light is determined by the composition material and size and shape of the quantum dots. Its frequency can be precisely adjusted by changing the size, shape and material of the quantum dots, thereby realizing 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 (Electron) and holes (Hole) on both sides converge in the quantum dot layer to form photons (Exciton), and light is emitted through the recombination of photons.

Mini LED

Mini LED technology can be used directly for RGB display or LCD backlight module. Among them, the LCD screen backlight module mainly uses Mini LED technology to improve the display effect.

The principle of its MiniLED technology is: Mini LED adopts direct backlight mode, which can be regarded as an upgraded version of ordinary LCD screen. Mini LED shrinks the traditional LED backlight beads to achieve more refined and dense backlight partitions, and cooperates with Local Dimming control to improve brightness and contrast, and enhance visual perception. Under the same conditions, Mini LED not only makes up for the disadvantage of OLED's easy screen burn-in, but also outperforms OLED in cost. While improving the picture, it also has cost advantages.

microLED

The last is microLED. The biggest difference between it and OLED is the luminescent material. OLED uses organic film, while microLED is inorganic micro light beads.

Its predecessor was the kind of large outdoor advertising wall. The dot matrix composed of inorganic light-emitting diodes looks okay from a distance, but it is really a small light bulb when you look at it closely, with a full sense of grain.



So the technological breakthrough of microLED is to further miniaturize these small light bulbs. Because of the different material properties, it has a longer screen life than OLED. But the disadvantage is that the production process is much more complicated, and the price will certainly be more expensive.


In summary, LCD, OLED and microLED, these three screen technologies represent three different technical schools. MicroLED has not yet been mass-produced. OLED is the representative of mobile phone screens, and LCD is the mainstream of TVs and computer monitors. At present, they are clearly divided.


As for miniLED and QLED, they are essentially LCD liquid crystals in the consumer market, but they use different technical solutions on the backlight module.