The luminescent organic materials and electrodes in the Encapsulation:OLED are very sensitive to oxygen and water, which will make them luminescent. In order to prevent this phenomenon, it is necessary to keep or prolong the life of the OLED panel by "encapsulation".
As mentioned above, OLED, which is illuminated by the organic matter itself, is easily affected by oxygen and water. Therefore, in the manufacturing process, the process of sealing is required to prevent oxygen and water from infiltrating into the organic material. The snack is also sealed for the maintenance of freshness, otherwise it will soon become soft after opening the package and the taste will disappear. And the OLED panel is also sealed to preserve organic matter, which is very important.
The sealing process is divided into four stages:
① Cell packaging glass manufacturing
② Using glass sealing
③ Place glass
④ Laser seal
Let's take a look at the steps shown below.
First, the package glass is loaded, and then it starts to clean. The audience, who has read this series of courses, feels that most of the processes start from cleanliness.
Liquid is used for wet cleaning to remove pollutants in glass manufacturing, packaging and transportation. Plasma cleaning is then carried out to remove organic pollutants on the surface. The adhesion of the unit seal can be improved by the plasma cleaning.
After cleaning, the sealant (an adhesive material) is applied to the edge of each unit. This process is called the unit sealant printing. In this process, precision is very important. Then, after covering the glass on the EV substrate, the sealant is heated and hardened instantly with a laser. So the sealant should be printed in a stable thickness, width and precise position.
After printing, it enters the drying stage. By removing the bubbles in the unit seals caused by solvents, such as liquid or gas dissolved in other substances, diluent, etc., to ensure the stability of the sealing quality.
The next step is "sintering". In the sintering process, the residual solvents, organic adhesives, etc., and the characteristics of the unit seal are changed to achieve the laser seal.
Solvents and adhesives used in the manufacture of sealing frit. Just as you can pour the cement into the sand and pour the water into the sand, you can use it. Because the character of the sand determines that it does not condense together, you need an adhesive to fix it. The binder is also solid, so you need a solvent to melt the adhesive. They are fully mixed, used for unit sealants (adhesives) and sealing processes.
Finally, the fused glass is cleaned again by the plasma. Through various processes, a smooth surface is made to remove the adsorbed moisture and other adsorbents to improve the adhesion.
The first step of the four stage of the seal process, the package glass preparation, is now over. The next step is to print the border sealant on the edge of the unit glass, as shown in the following figure, to seal the side of the glass.
The following is the third stage of the encapsulation process: "cementation". Cementation is the process of superposing the glass and glass up and down to the existing evaporation process. Through this process, the separated OLED glass is merged into one.
It uses UV (ultraviolet) equipment to reinforce the edge seal. The sclerosing sealant is responsible for preventing external air and water penetration, maintaining internal pressure, and so on.
This is the last stage, "unit seal". The cementation process is carried out on the whole glass. The laser equipment irradiates the laser to the sealant placed on each unit for instant melting and cementation.
Once all four steps are completed, a single glass OLED panel is completed. In the next step, the unit is processed and cut according to the size of the unit. After the completion of the cell processing, the cutting unit panel will undergo the module project with smart phone, tablet PC and so on, and then send it to the manufacturers of various electronic devices.