Light Emitting Display Device Pixel Isolation Structure
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Solution Overview
Problem
Light emitting display devices face issues with unwanted emission of light due to current leakage between adjacent pixels, leading to increased luminance and compromised image quality.
Innovation Solution
The implementation of a light emitting display device structure featuring a substrate with a transistor, insulating layers, a pixel electrode, an etch stopper, and a light emitting member with a charge generating layer and undercut opening structure, which separates the light emitting member and common electrode to prevent current leakage between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If continuous layers are used in the light emitting member, then manufacturing process is simplified, but current leakage occurs between adjacent pixels causing unwanted light emission
Solution Approach 1:
The light emitting member layers are segmented into discontinuous portions at the pixel boundaries, creating isolated regions over each pixel electrode. This segmentation prevents current leakage between adjacent pixels while maintaining continuous layers over each individual pixel, thus resolving the contradiction between manufacturing simplicity and current isolation.
Solution Approach 2:
The light emitting member exhibits different structural qualities in different regions: continuous layers over pixel electrodes for optimal light emission, and discontinuous portions at pixel boundaries for current isolation. This local variation in layer continuity allows the structure to simultaneously achieve good manufacturing characteristics and effective current confinement.
2Object-generated harmful factors
If discontinuous portions are provided in the light emitting member layers, then current leakage is prevented, but manufacturing complexity increases
Solution Approach 1:
The discontinuous portions are created by segmenting the light emitting member layers at specific locations (pixel boundaries) rather than making the entire structure discontinuous. This targeted segmentation achieves current isolation with minimal additional complexity, as the layers remain continuous over the majority of each pixel area.
Solution Approach 2:
The discontinuous portions of adjacent pixels are merged through the common electrode, which provides a continuous path for charge collection. This merging approach allows the light emitting member to be discontinuous for current isolation while the common electrode maintains continuity for proper device operation, reducing the overall complexity.
3Device complexity
If current leakage is allowed, then device structure is simpler, but image quality deteriorates due to unwanted light emission
Solution Approach 1:
The light emitting member is segmented to create electrical isolation between pixels, preventing current leakage that would compromise image quality. This segmentation is achieved through discontinuous portions of the layers at pixel boundaries, maintaining structural simplicity while ensuring high manufacturing precision for image quality.
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 minimizes unwanted light emission and maintains satisfactory image quality by ensuring that each pixel emits light independently, preventing luminance increases caused by current leakage.
Implementation Method 1
a light emitting member disposed on the pixel electrode and the pixel defining layer. The light emitting member includes a first light emitting part, a charge generating layer, and a second light emitting part
Data Source
AI summary
A light emitting display device includes a substrate, a transistor, a first insulating layer, a second insulating layer, a pixel electrode, a conductive member, a third insulating layer, and a light emitting material layer. The transistor overlaps the substrate. The first insulating layer overlaps the transistor. The second insulating layer overlaps the first insulating layer. The pixel electrode directly contacts the second insulating layer and is electrically connected to the transistor. The conductive member directly contacts at least one of the first insulating layer and the second insulating layer. The third insulating layer overlaps the second insulating layer, includes a hole, and includes an opening. The hole exposes the pixel electrode. The opening exposes the conductive member. The light emitting material layer overlaps the pixel electrode inside the hole, overlaps the third insulating layer, and has a discontinuity inside the opening.