Display Device Storage Line Overlap Aperture Ratio
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges in improving response time and aperture ratio, with increasing power source voltage leading to higher power consumption and liquid crystal material development reaching its limitations.
Innovation Solution
A display device design incorporating a switching element, liquid crystal capacitor, and storage capacitor, where the storage line overlaps the source line to optimize capacitance ratio and response time, maintaining a high aperture ratio without additional area requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power source voltage is increased to improve response time, then response time is improved, but power consumption is increased
Solution Approach 1:
The patent changes the capacitance ratio parameter between liquid crystal capacitor and storage capacitor to optimize response time. By adjusting the capacitance values and their ratio, the system achieves improved response time without requiring increased power source voltage, thus avoiding higher power consumption.
Solution Approach 2:
The patent introduces a new design dimension by overlapping the storage line with the source line in the planar layout. This spatial arrangement allows the storage capacitor to be formed within the existing pixel area without requiring additional area, enabling capacitance optimization without increasing device complexity or power consumption.
2Speed
If liquid crystal material with lower dielectric constant is used to improve response time, then response time is improved, but material development reaches limitations
Solution Approach 1:
Instead of changing liquid crystal material properties which are approaching development limits, the patent changes the electrical parameters of the capacitor system. By adjusting the capacitance ratio between liquid crystal capacitor and storage capacitor, the system achieves response time improvement through circuit design rather than material science limitations.
3Reliability
If storage line is formed independently in each pixel area to ensure capacitance, then capacitance is maintained, but aperture ratio is reduced
Solution Approach 1:
The patent merges the storage line with the source line by making them overlap in the planar layout. This combination allows the storage capacitor to share the source line area, eliminating the need for separate dedicated storage line area in each pixel. Consequently, the aperture ratio is maintained while the storage capacitance is still formed through the overlapping region between storage line and source line.
Solution Approach 2:
The source line serves dual functions: as the source electrode for the switching transistor and as one of the electrodes for the storage capacitor. This multi-functionality allows the same conductive structure to fulfill multiple electrical roles, maintaining storage capacitance without dedicating additional area that would reduce the aperture ratio.
Data Source
AI summary
A display device having improved aperture ratio includes a switching element, a liquid crystal capacitor and a storage capacitor. The switching element is electrically connected to a gate line and a source line crossing each other. The liquid crystal capacitor has a pixel electrode electrically connected to the switching element through a first contact to define a pixel area. The storage capacitor has a storage line partially overlapping the source line. The storage line is electrically connected to the pixel electrode through a second contact hole.