Display Substrate Active Layer Segmentation for Aperture Ratio
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Solution Overview
Problem
The development of high-resolution display technology has led to a reduction in pixel aperture ratio due to the increasing size of the driving circuit region in bottom-emitting OLEDs, which affects the storage capacitor's capacity and overall display performance.
Innovation Solution
A display substrate with a specific layer structure including a first metal layer, a first insulating layer, a metal oxide layer, and a second metal layer, where the metal oxide layer includes a first active layer with distinct conductivity, oxygen content, and thickness regions, and the second metal layer includes a gate electrode, source electrode, and drain electrode, optimized through two conductorization treatments to improve alignment accuracy and electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sub-pixel size is reduced to increase resolution, then the display resolution is improved, but the pixel aperture ratio is significantly reduced
Solution Approach 1:
The active layer is segmented into multiple regions with different conductivity characteristics: a first region with higher conductivity (lower oxygen content or thinner thickness) and a second region with lower conductivity (higher oxygen content or greater thickness). This segmentation allows the active layer to simultaneously provide low-resistance contact regions for electrodes and high-aperture regions for light emission, resolving the contradiction between resolution and aperture ratio.
Solution Approach 2:
Different regions of the active layer are assigned different local qualities: the first region (at edges) has higher conductivity suitable for electrical contact, while the second region (in the center) has lower conductivity and higher thickness suitable for light emission. This local differentiation enables the active layer to fulfill multiple functions within the same structure, maintaining both low resistance and high aperture ratio.
2Quantity of substance
If the driving circuit region size is increased to ensure storage capacitor capacity, then the capacitor capacity is improved, but the pixel aperture ratio is reduced
Solution Approach 1:
The active layer serves multiple functions simultaneously: it acts as a semiconductor channel for transistor operation, provides low-resistance contact regions for electrode connection, and maintains a high-aperture central region for light emission. This multi-functionality reduces the need for separate dedicated regions, thereby increasing the pixel aperture ratio while maintaining capacitor capacity.
3Reliability
If the conductivity of the active layer is increased to improve electrical characteristics, then the electrical performance is improved, but the oxygen content is reduced which may affect stability
Solution Approach 1:
The active layer has different oxygen content in different regions: the first region has lower oxygen content for high conductivity and electrical contact, while the second region has higher oxygen content for stability and light emission. This local quality differentiation allows the structure to simultaneously achieve good electrical characteristics and material stability.
Data Source
AI summary
A display substrate, a preparation method therefor, and a display apparatus. The display substrate includes a first metal layer, a metal oxide layer and a second metal layer, which are stacked on a base. The metal oxide layer includes a first active layer, the first active layer including a channel region, a source transition region, and a drain transition region, wherein both the source transition region and the drain transition region comprise a first region and a second region.