Active Device Array Substrate with Floating Shielding Patterns
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Solution Overview
Problem
Conventional liquid crystal displays suffer from light leakage due to unexpected twist of liquid crystal molecules near signal lines, which is mitigated by widening the black matrix, but this reduces the aperture ratio and affects brightness.
Innovation Solution
An active device array substrate with strip floating shielding patterns and strip capacitance electrodes is designed, where the strip floating shielding patterns are larger than the data lines and capacitance electrodes, forming a shielding structure that prevents light leakage while maintaining a high aperture ratio, and the strip capacitance electrodes are electrically connected to common or scan lines to provide a storage capacitor for stabilizing data voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the black matrix width is widened to prevent light leakage, then light leakage is reduced, but the aperture ratio is decreased and brightness is affected
Solution Approach 1:
The patent introduces a floating shielding pattern as an intermediary element positioned between the data line and the liquid crystal layer. This shielding pattern acts as a mediator that blocks the harmful electromagnetic field from twisting the liquid crystal molecules, thereby preventing light leakage without requiring an increase in black matrix width, thus preserving the aperture ratio
Solution Approach 2:
The patent extracts the light leakage prevention function from the black matrix structure and relocates it to a dedicated floating shielding pattern. By separating the shielding function from the black matrix, the black matrix can maintain its original narrow width (preserving aperture ratio) while the floating shielding pattern independently performs the light leakage prevention function
2Object-affected harmful factors
If the black matrix width is widened to prevent light leakage, then light leakage is reduced, but the brightness is affected
Solution Approach 1:
The floating shielding pattern serves as an intermediary that specifically targets and blocks the harmful electromagnetic field interaction between data lines and liquid crystal molecules. This selective shielding prevents light leakage caused by molecular twisting while leaving the optical path for display pixels unaffected, thereby maintaining brightness
Solution Approach 2:
The patent applies local quality by positioning the floating shielding pattern only in specific locations where data lines intersect with liquid crystal regions prone to unwanted twisting. This localized shielding approach prevents light leakage only where necessary, while leaving other areas with full optical transmission capability, thus preserving overall brightness
3Object-affected harmful factors
If floating shielding patterns are introduced to prevent light leakage, then light leakage is reduced, but device complexity increases
Solution Approach 1:
The patent merges the floating shielding pattern with the existing data line structure by positioning them in close proximity and using similar fabrication processes. The shielding pattern is integrated into the same layer structure as the data line, combining the signal transmission function with the shielding function, thereby reducing overall device complexity
Solution Approach 2:
The floating shielding pattern serves multiple functions: it acts as an electromagnetic shield to prevent liquid crystal twisting, serves as a structural element in the layered device architecture, and can be fabricated using the same material and process as the data line. This multi-functionality reduces the need for separate components and simplifies the overall device structure
Data Source
AI summary
An active device array substrate including a first patterned conductive layer, a dielectric layer, a second patterned conductive layer, a passivation layer and pixel electrodes is provided. The first patterned conductive layer includes scan lines, common lines, gates and strip floating shielding patterns. The dielectric layer covering the first patterned conductive layer has first contact holes which expose a portion of the common lines, respectively. The second patterned conductive layer includes data lines, sources, drains and strip capacitance electrodes. Each strip capacitance electrode is electrically connected to one of the common lines through one of the first contact holes. A gap is formed between each data line and one strip capacitance electrode, and the strip floating shielding patterns are disposed under the data lines, the gap and the strip capacitance electrodes. Each pixel electrode is electrically connected to one of the drains through one of the second contact holes.