Flexible OLED Spacer Segmentation for Uniform Coating
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Solution Overview
Problem
Existing organic electroluminescent devices face reliability issues due to moisture infiltration through non-uniform organic layer coating and poor stack coverage, leading to pixel shrinkage and failure, primarily caused by the bar-shaped spacers in the non-display area allowing organic layers to spread and create uneven steps during encapsulation.
Innovation Solution
The introduction of a flexible organic electroluminescent device with a modified spacer structure, where second and third spacers are arranged in a two-columnar form or straight line parallel to the display area's lateral surface, minimizing organic layer spread and enhancing the stack coverage of the passivation layer to prevent moisture infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If bar-shaped spacers are used in the non-display area, then the organic layer can be coated, but the organic layer spreads and creates uneven steps leading to poor stack coverage
Solution Approach 1:
The patent divides the single bar-shaped spacer into multiple columnar spacers arranged in a specific pattern. This segmentation prevents the organic layer from spreading laterally during coating, as the multiple smaller spacers create a more controlled deposition pattern compared to a single large bar-shaped spacer.
Solution Approach 2:
The patent transitions from a two-dimensional bar-shaped spacer structure to a three-dimensional arrangement of multiple columnar spacers with specific spacing and positioning. This dimensional change allows for better control of the organic layer deposition profile and improves stack coverage uniformity.
2Reliability
If the organic layer is coated over the bar-shaped spacer, then encapsulation is achieved, but moisture infiltration occurs through non-uniform coating
Solution Approach 1:
By segmenting the bar-shaped spacer into multiple columnar spacers, the organic layer coating process achieves better uniformity. The segmented structure prevents excessive lateral spreading of the organic material, resulting in a more uniform coating that provides effective moisture protection.
3Strength
If spacers are placed in the non-display area, then structural support is provided, but organic layer spread creates uneven steps
Solution Approach 1:
The patent segments the bar-shaped spacer into multiple smaller columnar spacers that maintain the necessary structural support function while reducing the lateral spread of the organic layer. The distributed arrangement of columnar spacers provides structural integrity without creating the uneven steps associated with single bar-shaped spacers.
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 configuration effectively suppresses moisture infiltration and enhances the reliability of the flexible display by ensuring uniform coating and improved passivation layer coverage, reducing the likelihood of pixel failures and maintaining display performance even when bent.
Implementation Method 1
an adhesive interposed between the substrate and barrier film to adhere the substrate to the barrier film
Implementation Method 2
an organic light emitting layer separately formed for each pixel region on the first electrode
Data Source
AI summary
The present invention relates to a flexible organic electroluminescent device, and the invention disclosed herein includes a switching thin film transistor and a drive thin film transistor formed at the each pixel region on a substrate; a first electrode connected to a drain electrode of the drive thin film transistor, and formed at the each pixel region; a bank formed on the display area and non-display area of the substrate; a spacer formed on a bank in the non-display area, and disposed in the vertical direction in parallel to a lateral surface of the display area; an organic light emitting layer separately formed for each pixel region; a second electrode formed on an entire surface of the organic light emitting layer; an organic layer formed on an entire surface of the substrate; a barrier film located to face the substrate.