Floating Electrode Transistor for LCD Aperture Ratio and Voltage Stability
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Solution Overview
Problem
In liquid crystal display (LCD) devices, the presence of a voltage-dividing transistor reduces the pixel aperture ratio and causes variations in storage voltage due to electrical connection between data and storage lines.
Innovation Solution
The implementation of a second transistor with floating electrodes between the source and drain electrodes allows for independent control of sub-pixel electrodes without an additional voltage-dividing transistor, enhancing the pixel aperture ratio and stabilizing storage voltage by reducing direct connection between data and storage lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a voltage-dividing transistor is used to control sub-pixel electrodes, then data signals can be divided and applied to multiple sub-pixels, but the aperture ratio of the pixel decreases due to the transistor occupying pixel region
Solution Approach 1:
The invention extracts the voltage-dividing transistor from the pixel region and places it in the common region shared by multiple pixels. This removes the transistor that was occupying pixel area, thereby increasing the aperture ratio while maintaining the voltage division function through the alternative path using the second transistor and floating electrode.
Solution Approach 2:
The invention moves the voltage division function from the horizontal plane (within pixel region) to the vertical stacking dimension by placing the second transistor and floating electrode structures in the common region below or above the pixel electrodes, allowing space reuse and increasing aperture ratio.
2Ease of operation
If a voltage-dividing transistor is turned on to apply data signals, then sub-pixel electrodes can be controlled, but the data line and storage line become electrically connected causing storage voltage variation
Solution Approach 1:
The floating electrode acts as an intermediary element that enables voltage division and sub-pixel control without creating a direct electrical connection between the data line and storage line. The second transistor controls the coupling between the floating electrode and data line, while the capacitive coupling to the sub-pixel electrode provides the necessary voltage division without harmful direct connections.
Solution Approach 2:
The invention segments the voltage control function by using a floating electrode that is capacitively coupled to the sub-pixel electrode rather than directly connected. This segmentation allows independent control of the data signal path while isolating the storage line from direct electrical connection, preventing storage voltage variation.
3Adaptability or versatility
If floating electrodes are added to the second transistor, then independent control of sub-pixel electrodes is achieved without voltage-dividing transistor, but device structure becomes more complex
Solution Approach 1:
The floating electrode structure serves multiple functions: it acts as a gate for the second transistor, provides capacitive coupling for voltage division, and enables independent sub-pixel control. By making this single structure multi-functional, the invention achieves complex control capabilities without proportionally increasing device complexity.
Solution Approach 2:
The invention merges the gate electrode and floating electrode into a single continuous conductive structure for the second transistor. This merging reduces the number of separate components and simplifies the fabrication process while maintaining the ability to independently control sub-pixel electrodes through the floating portion.
Data Source
AI summary
A liquid crystal display which enhances an aperture ratio and stabilizes a storage voltage includes a first substrate, a second substrate opposing the first substrate, a liquid crystal layer between the first substrate and the second substrate, a gate line, a data line, a first sub-pixel electrode, and a second sub-pixel electrode on the first substrate, a first transistor connected to the gate line, the data line, and the first sub-pixel electrode, and a second transistor connected to the gate line, the data line, and the second sub-pixel electrode and including a source electrode, a drain electrode and at least one floating electrode between the source electrode and the drain electrode.