Display Substrate Light-Shield Layout for Inter-Subpixel Leakage
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Solution Overview
Problem
Conventional display substrates suffer from light leakage issues, particularly in bottom-emission type OLED displays, which affect color accuracy due to misalignment of layers, leading to unwanted white light transmission through inter-subpixel regions.
Innovation Solution
A display substrate design featuring a base substrate with a thin film transistor and strategically positioned light shielding layers that cover inter-subpixel regions, ensuring the light shielding layers are outside the active layer projections, thereby blocking light leakage and maintaining color integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a transparent electrode is removed from a display device, then manufacturing complexity and cost are reduced, but the device requires connection to a driving circuit board which increases assembly complexity
Solution Approach 1:
The patent combines the transparent electrode pattern and the connection electrode pattern into a single conductive layer formed by one photolithography process. The transparent electrode portion connects to the TFT, while the connection electrode portion extends to the bonding pad for external connection, eliminating the need for separate transparent electrode and connection electrode layers
Solution Approach 2:
The conductive layer serves multiple functions: it acts as the transparent electrode for the display area, provides connection electrodes for bonding to the driving circuit board, and includes bonding pads for external connections. This multi-functional design eliminates the need for separate dedicated connection electrodes
2Productivity
If the transparent electrode is extended to the bonding pad for direct connection, then the number of manufacturing processes is reduced, but the transparency and display quality in the electrode region may be compromised
Solution Approach 1:
The conductive layer has different properties in different regions: in the display area it maintains high transparency with optimized thickness and material composition, while in the connection area it provides sufficient electrical conductivity for bonding. The transparent electrode portion uses ITO or IZO with controlled thickness to balance transparency and conductivity
Solution Approach 2:
The conductive layer is functionally segmented into the transparent electrode pattern for display and the connection electrode pattern for bonding, both formed in one layer but with different design requirements optimized for their respective functions
3Device complexity
If the connection electrode pattern is formed in the same photolithography process as the transparent electrode pattern, then manufacturing steps are reduced, but the design flexibility for optimizing each electrode's performance is limited
Solution Approach 1:
The single conductive layer is designed with locally optimized properties: the transparent electrode region uses specific material composition and thickness for maximum transparency, while the connection electrode region is designed for optimal electrical connection and bonding pad alignment
Solution Approach 2:
The conductive layer pattern is segmented into functionally distinct regions (transparent electrode pattern and connection electrode pattern) that are formed simultaneously but can be independently optimized for their respective functions
Data Source
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AI summary
Provided is a display substrate. The display substrate includes a base substrate (10)； a thin film transistor (110) for driving image display including an active layer (AL)； and a first light shielding layer (80a) on the base substrate (10) and in an inter-subpixel region (2) between two adjacent subpixel regions (1). A projection of the first light shielding layer (80a) on the base substrate (10) at least partially covers a projection of the inter-subpixel region (2) between two adjacent subpixel regions (1) on the base substrate (10). The projection of the first light shielding layer (80a) on the base substrate (10) is outside a projection of the active layer (AL) on the base substrate (10).