OLED Encapsulation Using Photo-isomerization for Narrow Bezel
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Solution Overview
Problem
Existing thin-film encapsulation methods for OLED display devices suffer from a shadow effect, leading to a wide device frame and inadequate edge coverage, as the thinner film edges are less than 90% of the desired thickness and can extend over 200 μm, causing a bezel widening issue.
Innovation Solution
A method involving the formation of first and second barrier walls in the peripheral region of the display substrate, with inorganic and organic thin-film encapsulation layers alternately laminated, where the inorganic thin-film encapsulation layer is disconnected and removed between the barrier walls, using a photo-isomerization material layer and an elastic protective layer to facilitate precise edge coverage without excess film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin-film encapsulation is used to achieve thin thickness and high barrier properties, then the encapsulation effectiveness is improved, but the shadow effect causes the film edges to be thinner than desired and extends beyond the barrier walls, leading to wide device frame
Solution Approach 1:
The encapsulation structure is segmented into multiple functional components: first and second barrier walls define a peripheral region, while inorganic and organic thin-film encapsulation layers are deposited alternately. The inorganic thin-film encapsulation layer is selectively removed from the region between barrier walls, creating distinct functional zones that prevent shadow effect while maintaining edge coverage precision.
Solution Approach 2:
The inorganic thin-film encapsulation layer is extracted (removed) from the specific region between the first and second barrier walls. This selective removal eliminates the shadow effect in the peripheral region while preserving the encapsulation function in the display region, thereby preventing bezel widening without compromising edge coverage.
2Reliability
If the inorganic thin-film encapsulation layer is formed to cover the entire substrate including peripheral region, then complete encapsulation is achieved, but excess film forms between barrier walls causing shadow effect and wide bezel
Solution Approach 1:
Different regions of the substrate receive different treatments: the display region maintains complete encapsulation with alternating inorganic and organic layers for high reliability, while the peripheral region between barrier walls has the inorganic layer removed to eliminate shadow effect. This local differentiation ensures encapsulation integrity where needed while minimizing bezel area where excess film would form.
Solution Approach 2:
The potential harm of excess inorganic film forming between barrier walls (which would cause shadow effect and wide bezel) is converted into a benefit by selectively removing this excess film. The removal process transforms what would be a defect into an opportunity to achieve precise edge coverage and narrow bezel while maintaining complete encapsulation in the display region.
3Length of stationary object
If the inorganic thin-film encapsulation layer is disconnected and removed between barrier walls, then shadow effect is avoided and narrow bezel is achieved, but the encapsulation process becomes more complex
Solution Approach 1:
The first and second barrier walls are formed in advance to define the peripheral region before thin-film deposition. This preliminary structuring creates clear boundaries that guide the subsequent selective removal process, making the overall process more controllable and less complex than it would be without pre-defined barrier structures.
Solution Approach 2:
The selective removal of the inorganic thin-film encapsulation layer between barrier walls is achieved through chemical etching processes rather than mechanical means. This substitution of chemical for mechanical processes simplifies the removal operation and reduces process complexity while achieving the desired narrow bezel effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach avoids the shadow effect, achieving a narrow bezel without compromising the overall encapsulation effect, ensuring precise edge coverage and maintaining the integrity of the display substrate.
Implementation Method 1
forming a photo-isomerization material layer between the first barrier wall and the second barrier wall, the photo-isomerization material layer being configured to be converted from a solid state to a liquid state under the irradiation with light having a first wavelength, and converted from the liquid state to the solid state under the irradiation with light having a second wavelength
Data Source
AI summary
Provided is a method for encapsulating a display substrate, including: forming a first barrier wall and a second barrier wall in a peripheral region of the display substrate; and forming inorganic thin-film encapsulation layers and organic thin-film encapsulation layers alternately laminated on the display substrate, all of the organic thin-film encapsulation layers being located in a region surrounded by the first barrier wall, the forming at least one of the inorganic thin-film encapsulation layers comprises: forming the inorganic thin-film encapsulation layer on the display substrate, a portion of the inorganic thin-film encapsulation layer being located between the first barrier wall and the second barrier wall; and disconnecting the portion of the inorganic thin-film encapsulation layer between the first barrier wall and the second barrier wall from the other portions of the inorganic thin-film encapsulation layer, and removing the portion.