LCD Pixel Circuit with Independent Switches and Capacitors
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges due to the use of voltage divider transistors, which occupy pixel area, decrease aperture ratio, and cause variations in storage voltage when turned on, leading to electrical connection issues between data lines and storage electrodes.
Innovation Solution
The implementation of a liquid crystal display device with multiple switches and capacitors connected to gate and data lines, where at least two capacitors have different capacitance values, allowing for a time division scheme and improved pixel voltage control, reducing kick-back voltages and enhancing visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a voltage divider transistor is used to divide data signals to sub-pixel electrodes, then the pixel can display images with enhanced visibility, but the transistor occupies pixel area and decreases the aperture ratio
Solution Approach 1:
The voltage divider transistor is extracted from the pixel area and relocated to a peripheral region. The pixel now includes first, second, third, and fourth switches connected to gate and data lines, with sub-pixel electrodes connected to these switches, eliminating the need for a voltage divider transistor within the pixel area and thereby increasing the aperture ratio while maintaining visibility enhancement capabilities.
2Adaptability or versatility
If a voltage divider transistor is used to divide data signals, then sub-pixel electrodes can receive different voltage levels, but the storage voltage of the storage electrode varies due to data signal interference when the transistor is turned on
Solution Approach 1:
The pixel circuit is segmented into multiple independent switch-controlled paths. Each sub-pixel electrode is connected to its own switch (first, second, third, or fourth switch), allowing independent control of voltage levels applied to each sub-pixel electrode through data lines. This segmentation isolates the storage electrode from data signal interference, maintaining storage voltage stability while enabling versatile voltage control for enhanced visibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the visibility of LCD devices by minimizing kick-back voltages and maintaining consistent pixel voltages, thereby reducing ripple effects and horizontal crosstalk, leading to improved image quality.
Implementation Method 1
Liquid crystal molecules in the liquid crystal layer realign based on voltages applied to the electrodes. The realignment of the liquid crystal molecules adjusts the amount of transmitted light to display an image.
Implementation Method 2
a first capacitor connected between a gate electrode and a source electrode of the first switch; a second capacitor connected between a gate electrode and a source electrode of the second switch; a third capacitor connected between a gate electrode and a source electrode of the third switch; and a fourth capacitor connected between a gate electrode and a source electrode of the fourth switch
Data Source
AI summary
A liquid crystal display device includes at least one pixel that includes first, second, third, and fourth switches connected to at least one gate line and at least one data line, a first sub-pixel electrode connected to the first switch, a second sub-pixel electrode connected to the second switch, a third sub-pixel electrode connected to the third switch, a fourth sub-pixel electrode connected to the fourth switch, a first capacitor connected between a gate electrode and a source electrode of the first switch, a second capacitor connected between a gate electrode and a source electrode of the second switch, a third capacitor connected between a gate electrode and a source electrode of the third switch, and a fourth capacitor connected between a gate electrode and a source electrode of the fourth switch. At least two of the first, second, third, and fourth capacitors have different capacitance values from one another.