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--- screen_manufacturing [2026/04/15 17:17] – [5. EML (emission layer) fabrication] sophie
+++ screen_manufacturing [2026/04/16 09:28] (current) – [8. encapsulation] antoine
@@ Line 28: / Line 28: @@
 ##### deposition of organic emissive materials
 There are different deposition methods depending on the organic emissive materials selected for the OLED.
-  * **vacuum thermal evaporation combined with an FMM** (Fine Metal Mask) - _for small sized displays_ (([[https://advanced.onlinelibrary.wiley.com/doi/10.1002/aelm.202500555|Vacuum Thermal Evaporation for OLEDs: Fundamentals, Optimization, and Implications for Perovskite LEDs]], C. Shen, Y. Hu, S. Zhou, et al., 2025)): This method is not selective, meaning the material is deposited everywhere in the equipment chamber : a FMM (Fine Metal Mask) is placed on top of the substrate to hide areas where no material should be deposited. The emissive layer of small display OLEDs consists of 3 emissive materials (respectively emitting red, blue and green light) that are placed side by side. Hence, there are actually 3 deposition steps using 3 different FMMs, one for each emissive material.
+  * **vacuum thermal evaporation combined with an FMM** (Fine Metal Mask) - _for small sized displays_ (([[https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/aelm.202500555|Vacuum Thermal Evaporation for OLEDs: Fundamentals, Optimization, and Implications for Perovskite LEDs]], C. Shen, Y. Hu, S. Zhou, et al., 2025)): This method is not selective, meaning the material is deposited everywhere in the equipment chamber : a FMM (Fine Metal Mask) is placed on top of the substrate to hide areas where no material should be deposited. The emissive layer of small display OLEDs consists of 3 emissive materials (respectively emitting red, blue and green light) that are placed side by side. Hence, there are actually 3 deposition steps using 3 different FMMs, one for each emissive material.
   * **For larger sized display**, the use of an FMM is not appropriate due to a loss of resolution when the substrate size is increased.
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 ### 7. cathode fabrication
 ### 8. encapsulation
+OLED devices are highly sensitive to moisture and oxygen. They require a water vapour transmission rate (WVTR) of less than 10<sup>–6</sup> g/m²/day. For this reason, the encapsulation process is crucial for maintaining a long lifetime. There are multiple encapsulation technologies:
+{{ ::classification_of_encapsulation_technologies.png?400 |}}
+The use of these technologies depends on multiple parameters of the screen.
+####Frit-seal
+{{ :frit-sealed_structure.png?400 |}}
+{{ ::frit-seal_process.png?400 |}}
+This method can't be used for large or flexible screens.
+####Face-seal
+{{ ::face-seal_structure.png?400 |}}
+{{ ::face-seal_process.png?400 |}}
+This method is used for large rigid screens.
+####Thin-Film Encapsulation
+{{ ::tfe_process.png?400 |}}
+{{ ::tfe_structure.png?400 |}}
+This method can be used for flexible screens.
+Sources : ([https://www.wiley.com/en-es/Flat+Panel+Display+Manufacturing-p-9781119161363|Flat Panel Display Manufacturing])
 ### 9. assembly
 ### 10. testings