OLED display technology
September 6, 2021
1. OLED display technology is divided into two types: polymer manufacturing process and small molecule manufacturing process according to the manufacturing process.
As the polymer manufacturing process (PLED) does not require a thin film process, the equipment investment and production costs are much lower than TFT-LCD (similar to CD-R).
Spin-coating method of coating mold) is more conducive to the development of large-size displays.
However, since the attenuation constant of each color of PLED is different, it is not only difficult to make the product colorful, but the service life of the product is also affected.
Although small-molecule organic electroluminescent elements are better than polymer organic electroluminescent elements in terms of colorfulness, the equipment investment and production cost are relatively high (because the heating evaporation method is used to evaporate multilayer organic film materials, in order to avoid Mutual contamination, so expensive multi-chamber vacuum equipment must be used, and the drive voltage is large and the output rate is low.
Polymer components have better performance in terms of thermal stability, so they can be used in higher temperature working environments and can tolerate higher current densities.
However, due to the difficulty of independent positioning of the red, basket and green three pixels, full-color displays have not yet been introduced. .
2. OLED display technology is divided into passive (passive drive passive matrix, namely PM-OLED) and active (active drive active matrix, AM-OLED) according to the driving mode.
Passive type is suitable for small-size panels, because its instantaneous brightness is proportional to the number of cathode scanning columns, so it needs to operate under high pulse current, which will shorten the life of the pixel.
And because of the scanning relationship, the resolution is limited, but low cost and simple manufacturing process are its major advantages.
The active type is just the opposite of the passive type.
Although the cost is more expensive and the process is more complicated (still easier than TFT-LCD), each pixel can be driven continuously and independently, and the driving signal can be memorized, without operating under high pulse current ,
High efficiency, extended lifespan, suitable for full-color OLED display products with large size, high resolution and high information capacity.
(1) Compared with the crystal layer of LED or LCD, the organic plastic layer of OLED is thinner, lighter and more flexible.
(2) The light-emitting layer of OLED is relatively light, so its base layer can be made of flexible materials instead of rigid materials. OLED base layer is made of plastic, while LED and LCD use glass base layer.
(3) OLED is brighter than LED, and the organic layer of OLED is much thinner than the corresponding inorganic crystal layer in LED. Therefore, the conductive layer and emission layer of OLED can adopt a multilayer structure. In addition, LEDs and LCDs require glass as a support, and glass absorbs part of the light. OLED does not need to use glass.
(4) OLED does not need to use the backlight system in LCD. When the LCD works, it will selectively block certain backlighting areas to make the image appear, while the OLED emits light by itself. Because OLEDs do not require a backlighting system, they consume less power than LCDs (most of the power consumed by LCDs is used for backlighting systems). This is especially important for battery-powered devices such as mobile phones.
(5) OLED is easier to manufacture and can be made into larger size. OLED is made of plastic, so it can be made into a large-area sheet. It is much more difficult to use so many crystals and pave them flat.
(6) The field of view of OLED is very wide, up to about 170 degrees. However, the LCD needs to block light when working, so there are natural observation obstacles at certain angles. OLED itself can emit light, so the field of view is much wider.