OLED Pixel Definition Layer Lamination for Desiccant Expansion Control
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Solution Overview
Problem
Desiccants in the pixel definition layer of OLED display units expand due to water absorption, causing separation from other layers and allowing external water and oxygen to invade the organic light emitting unit, damaging the structure.
Innovation Solution
A pixel definition layer is constructed with a lamination structure comprising two or more layers, where desiccants are evenly distributed in the uppermost layer, using polymer materials with functional groups such as alkenyl, carboxyl, and amine groups that react to form a dense mesh structure, preventing film separation and water invasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If desiccants are added to the pixel definition layer to absorb moisture, then the OLED unit stability is improved, but the pixel definition layer separates from other layers causing gaps that allow water and oxygen invasion
Solution Approach 1:
The pixel definition layer is divided into multiple sub-layers (first pixel definition layer, second pixel definition layer, third pixel definition layer) with desiccants distributed across different layers. This segmentation prevents the entire layer from expanding uniformly and separating from other layers, while still maintaining effective moisture absorption throughout the structure.
Solution Approach 2:
Desiccants are selectively distributed to specific regions and layers rather than uniformly throughout the entire pixel definition layer. The first, second, and third pixel definition layers contain desiccants in different quantities and positions, creating local variations in moisture absorption capacity that prevent uniform expansion and layer separation.
2Object-affected harmful factors
If desiccants absorb water to maintain dryness, then moisture protection is improved, but the desiccants expand causing film separation and sealing structure damage
Solution Approach 1:
The pixel definition layer is segmented into multiple sub-layers with desiccants distributed across them. This segmentation contains the expansion of desiccants within specific sub-layers, preventing the expansion from propagating through the entire layer and causing seal rupture.
Solution Approach 2:
Desiccants are placed in specific local regions within the pixel definition layer structure rather than uniformly distributed. This local placement allows moisture absorption in critical areas while limiting expansion effects in seal-critical regions, preserving sealing structure integrity.
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
The lamination layer structure with desiccants effectively prevents water invasion, maintaining the integrity of the OLED display unit by suppressing film separation and enhancing the sealing structure.
Implementation Method 1
desiccants are distributed evenly in the second lamination layer... desiccants in the pixel definition layer expand due to water absorption
Implementation Method 2
when a temperature is increased, the second functional group and the first functional group on an abutment place between the first lamination layer and the second lamination layer are reacted chemically to form a third lamination layer
Data Source
AI summary
A display unit, a display unit manufacturing method, and an organic light emitting diode display device are provided. The display unit includes: a substrate; a thin film transistor layer disposed above the substrate; an anode metal layer disposed above the thin film transistor layer; a pixel definition layer disposed above the anode metal layer; a light emitting structure disposed above the pixel definition layer. The pixel definition layer includes a first lamination layer and a second lamination layer disposed above the first lamination layer. Desiccants are distributed evenly in the second lamination layer.