The OLED panel can be "printed", and the LCD shows a high degree of panic.
can the OLED panel be made by "inkjet printing"? You are right. If OLED wants to conquer the mainstream market, it may have to rely on this technology
at the end of November, BOE announced that it had successfully developed China's first 55 inch 4K OLED display using inkjet printing technology, which is expected to break the monopoly pattern of Korean enterprises in the field of large-size OLEDs
the mainstream OLED production generally adopts the evaporation process. This technology mainly faces the problems of yield and cost. Compared with the evaporation process, the OLED panel manufacturing process of inkjet printing technology is a feasible method to reduce the production cost
in fact, many panel manufacturers at home and abroad have long started to develop inkjet printing technology, including Samsung, LG, BOE, csot, etc. As early as the end of last year, joled, an affiliated enterprise of Japanese display company (JDI), announced that the 21.6-inch OLED panel produced by the "world's first" printing production method has been supplied. In the early stage, it was mainly used for the display of medical devices
what is the difference between evaporation and inkjet printing
oled's light-emitting principle is to make a layer of light-emitting material with a thickness of tens of nanometers on ITO glass - that is, what people usually call the self luminous material of OLED screen pixels. There is a metal electrode above the light-emitting layer, and the electrode is applied with voltage, and the light-emitting layer generates light radiation; Electrons and holes are injected from the Yin and Yang levels respectively. The injected electrons and holes are transmitted in the organic layer and compound in the light-emitting layer. The molecules in the light-emitting layer are excited to produce singlet excitons, and the singlet exciton radiation attenuates and emits light, thus forming pixel points
vacuum evaporation
the most commonly used method for forming organic layers is "evaporation". Evaporation is similar to evaporation. When boiling water in the pot, the steam becomes dew on the lid. The difference is that evaporation uses organic materials instead of water, and is heated in a vacuum rather than under normal atmospheric pressure
oled screen can actually "print 2. Economy: brush" out. LCD indicates high panic.
evaporation must be carried out in vacuum first, that is, in the equipment called vacuum chamber. The manufactured large LTPS backplane can be used for three-way data comparison, curve amplification, reduction, local inspection and other operations, and color patterning in the vacuum chamber
once the LTPS is manufactured and placed in the evaporation vacuum chamber, then a precision metal mask (FMM) is placed under the LTPS substrate. The mask is a device with small holes carved on the steel sheet, so when the organic material is evaporated, it can only be deposited at a specific position. When the mask is ready, put the evaporation source under it and heat it to the appropriate temperature. When heating starts, small organic molecules in the molecular unit pass through the mask and accumulate to the desired position
inkjet printing
inkjet printing technology is a technology that sprays less than dozens of PL (one trillion liters) of OLED ink for mass production of display screens, just like inkjet printing on paper. Compared with the evaporation method of vaporizing organic matter in vacuum, inkjet printing technology has the advantages of being able to produce under normal pressure, less ink dripping outside the substrate, and improving the efficiency of material use
in order to perform ink-jet printing, OLED materials must first be melted in solvent to make them into ink shape. The ink containing OLED material is printed between the grids of the substrate through the nozzle of the inkjet head. After the solvent is removed through the drying process, OLED material printing can be completed. Inkjet printing technology can be used in various types of display screen manufacturing, and its application prospect in the field of large-size OLED is particularly promising. This is because the substrate required for making large-scale display panels should be higher than that of the 8th generation. Compared with vacuum evaporation, inkjet method has more advantages in making large-area equipment
what are the advantages of inkjet printing over evaporation process
the process is simpler. The evaporation efficiency of organic light-emitting materials is higher, and the material utilization rate is low. During evaporation, the organic material gas is deposited on the glass substrate without difference
as a large-size fine metal mask, this process cannot be applied to the manufacture of large-size panels. The manufacturing cost is lower. In the use of raw materials for OLED panels, printing OLED saves about 90% than evaporation technology
what are the difficulties of inkjet printing
ink: the stability of ink is the key factor of printing, and in addition to its own property change factors, the larger factor that affects the stability of ink and the smooth switching between various control situations is bubbles. Assuming that the existing manufacturers can provide stable and large amounts of impurity free ink, bubbles will be introduced into the ink during transportation and filling, and there is no good solution to how to remove bubbles for the time being
nozzle: except for the single nozzle and single nozzle system used in small R & D machine, the single nozzle and multi nozzle system is generally used above the medium-sized platform. This nozzle can be used in the printing process with the first suspension bed hydrocracking (VCC) pilot evaluation device in China - Yanchang Petroleum Group suspension bed hydrocracking pilot evaluation device, which has recently made a major breakthrough in the coal oil slurry feed experiment. Multiple nozzles can be used for printing, so that the ink volume in each pixel can be homogenized on the premise of improving production efficiency
film formation: film formation is also one of the difficulties of solution printing. When the ink is printed, it begins to volatilize on the surface. Generally, the volatilization speed of the ink edge is faster, and the coffee ring phenomenon will appear
summary: our life has been inseparable from all kinds of screens, and all kinds of data generated around the screen are becoming more and more valuable. The three screens on TV, TV and car have also become the most important entry for future information competition, and the most basic screen technology will continue to develop and usher in new breakthroughs
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