Electroluminescent Pixel Structure with Variable Micro Cavity Lengths
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Solution Overview
Problem
Conventional electroluminescent display panels face limitations in aperture ratio and resolution due to light mixing between adjacent sub-pixel regions of different colors, which restricts further improvement in display performance.
Innovation Solution
A pixel structure for an electroluminescent display panel is designed with three sub-pixel regions, each having a unique anode, organic light-emitting layer, and cathode, along with micro cavities of varying lengths to prevent light mixing, allowing for the use of shared organic light-emitting layers and reduced fine metal mask usage during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spacing is disposed between adjacent sub-pixel regions to avoid light mixing, then light mixing is prevented, but aperture ratio and resolution cannot be improved further
Solution Approach 1:
The patent divides each sub-pixel region into multiple micro-emitting units arranged in a matrix, with each unit having its own micro-cavity structure. This segmentation allows independent control and light emission from each micro-unit, preventing light mixing between adjacent sub-pixels while increasing the overall aperture ratio by utilizing the space more efficiently.
Solution Approach 2:
The patent implements different cavity lengths in different micro-emitting units within the same sub-pixel region. Each micro-unit has locally optimized cavity length tailored to its specific color emission requirements, enabling precise color control and preventing light mixing while maintaining high aperture ratio.
2Object-affected harmful factors
If a fine metal mask is used to form separate organic light-emitting layers in each sub-pixel region, then color purity is maintained, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the organic light-emitting layer formation process by using a common layer that spans multiple sub-pixel regions. Instead of requiring separate fine metal mask patterns for each sub-pixel, a single continuous organic light-emitting layer is deposited, which is then selectively activated in different micro-units through electrical control, significantly reducing mask complexity.
Solution Approach 2:
The patent controls color emission by changing the cavity length parameter of each micro-emitting unit rather than relying on separate material layers. By adjusting the optical cavity length, different colors are achieved from the same organic light-emitting material, eliminating the need for complex multi-layer mask structures.
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 approach enhances the aperture ratio and resolution while minimizing light mixing, enabling the generation of distinct primary color lights with improved color purity and saturation without the need for color filters.
Implementation Method 1
the first organic light-emitting layer comprises a first organic light-emitting material for generating a first primary color light in the first sub-pixel region
Implementation Method 2
A first micro cavity is formed between the first anode and the first cathode in the first sub-pixel region. A second micro cavity is formed between the second anode and the second cathode in the second sub-pixel region. A third micro cavity is formed between the third anode and the third cathode in the third sub-pixel region. The first micro cavity, the second micro cavity, and the third micro cavity have different cavity lengths.
Data Source
AI summary
A fabrication method of a pixel structure of an electroluminescent display panel includes the following steps. A substrate is provided. A first anode, a second anode and a third anode are formed in a first sub-pixel region, a second sub-pixel region and a third sub-pixel region respectively. A first organic light-emitting layer is formed in the first sub-pixel region by using a first fine metal mask. A second organic light-emitting layer is formed in the second sub-pixel region and the third sub-pixel region by using a second fine metal mask. A first cathode, a second cathode and a third cathode are formed in the first sub-pixel region, the second sub-pixel region, and the third sub-pixel region, respectively. The first micro cavity in the first sub-pixel region, the second micro cavity in the second sub-pixel region and the third micro cavity have different cavity lengths.