OLED Pixel Trench Structure to Prevent Electrode Contact
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Solution Overview
Problem
The risk of exposure and contact between functional layers and the common electrode at the peripheral portion of the organic layer in OLED display devices leads to performance degradation, and the challenge of forming organic layers without using masks to prevent crosstalk between adjacent pixels.
Innovation Solution
A display device design with trenches in the insulating layer that are deeper at lower levels and inclined side surfaces to separate organic layers into each pixel, using a vacuum deposition method without a mask, ensuring the organic layer is formed without exposure to the common electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic layers are formed by stacking multiple functional layers, then the display device can achieve proper light emission function, but other functional layers and light-emitting layers may be exposed from the uppermost functional layer at the peripheral portion and come into contact with the common electrode, resulting in performance degradation
Solution Approach 1:
The patent divides the organic layer formation process into multiple functional layers (hole transport layer, light-emitting layer, electron transport layer) and uses a mask to segment the deposition area, ensuring each layer is formed only in the intended pixel region and preventing peripheral exposure to the common electrode
Solution Approach 2:
The mask is prepared and positioned before the vacuum deposition process begins, preliminarily defining the deposition pattern. This preliminary action ensures that all functional layers are deposited only within the confined pixel areas, preventing any layer from exposing at the periphery and contacting the common electrode
2Reliability
If a mask is used to form organic layers in each pixel, then crosstalk between adjacent pixels can be suppressed, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The mask physically segments the deposition field into discrete pixel regions, ensuring that organic layers are deposited only in the intended pixel areas. This segmentation effectively suppresses crosstalk between adjacent pixels by preventing material deposition in unintended areas
Solution Approach 2:
The mask serves as an intermediary tool between the deposition source and the substrate, controlling where material is deposited. This intermediary approach achieves precise pixel-level patterning without requiring complex post-deposition processing or alignment steps
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 design suppresses current leakage and prevents performance degradation by isolating functional layers from the common electrode, while allowing for efficient formation of organic layers without masks, reducing manufacturing costs and crosstalk.
Implementation Method 1
a method of forming the organic layer by dividing it into each pixel using a vapor deposition method without using a mask
Data Source
AI summary
According to one embodiment, a display device includes first and second lower electrodes, a second insulating layer including a first trench, a light emitting layer and an upper electrode. The first trench includes first, second and third trench portions. A first gap in a lower portion of the first trench portion is greater than a second gap in an upper portion of the first trench portion, a third gap in a lower portion of the second trench portion is greater than a fourth gap in an upper portion of the second trench portion, and a fifth gap in a lower portion of the third trench portion is greater than a sixth gap in an upper portion of the third trench portion.