OLED Display Adhesive Layer Step Compensation
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Solution Overview
Problem
OLED display devices face reliability issues due to defective bonding between the substrate and encapsulation substrate, leading to moisture and oxygen ingress, which damages the OLED, caused by a step difference between the display and non-display regions.
Innovation Solution
Incorporating a step-difference compensation portion, either integrally formed with the non-display region or varying the thickness of the adhesive layer, to ensure uniform bonding and prevent external contaminants from reaching the OLED.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the substrate and encapsulation substrate are bonded via an adhesive layer in the related art OLED display device, then the bonding process is simple, but a step difference is formed between the display region and non-display region causing defective bonding
Solution Approach 1:
The adhesive layer is designed with spatially varying thickness: a first thickness in the display region and a greater second thickness in the non-display region. This local differentiation compensates for the step difference caused by the thicker non-display region, ensuring uniform bonding pressure and preventing defective bonding while maintaining a simple bonding process.
Solution Approach 2:
The thickness parameter of the adhesive layer is changed across different regions of the substrate. By increasing the adhesive layer thickness in the non-display region relative to the display region, the bonding process accommodates the step difference and achieves reliable bonding throughout the entire substrate surface.
2Strength
If the encapsulation substrate is pressed onto the substrate including OLED, then bonding is achieved, but moisture and oxygen can enter through the step difference region and damage the OLED
Solution Approach 1:
The adhesive layer's varying thickness creates a localized solution where the thicker portion in the non-display region fills the step difference space. This eliminates gaps and voids that would otherwise serve as pathways for moisture and oxygen to reach the OLED, while maintaining appropriate bonding strength in both regions.
3Device complexity
If the adhesive layer thickness is uniform across the substrate, then the manufacturing process is simple, but the step difference causes defective bonding in the non-display region
Solution Approach 1:
Rather than using a complex multi-layer adhesive structure, the invention achieves bonding uniformity through a simple variation in adhesive layer thickness. The adhesive layer is applied with a first thickness in the display region and a second, greater thickness in the non-display region, providing a straightforward manufacturing approach that ensures uniform bonding pressure across the entire substrate.
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 solution effectively compensates for the step difference, ensuring a strong bond between the substrate and encapsulation substrate, thereby enhancing the reliability of the OLED display device by preventing moisture and oxygen ingress.
Implementation Method 1
an encapsulation substrate bonded to the substrate via an adhesive layer
Data Source
AI summary
An organic light emitting diode (OLED) display device including a substrate having a display region and a non-display region surrounding the display region; an OLED on the substrate in the display region; an encapsulation substrate bonded to the substrate via an adhesive layer such that the encapsulation substrate and the substrate face each other; and a step-difference compensation portion in the non-display region and configured to compensate for a step difference between the display region and the non-display region.