LCD Driving with Symmetrical Image Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid crystal display devices face issues such as reduced aperture ratio due to common voltage supply lines, flicker caused by parasitic capacitance, horizontal crosstalk, DC offset voltage, afterimage generation, and increased heat and current consumption due to large image signal swing widths.
Innovation Solution
A liquid crystal display device and driving method where each liquid crystal cell is connected to two adjacent data lines, with symmetrical first and second image signals supplied to drive the liquid crystal cells, eliminating the need for a common voltage and reducing power consumption by inverting signal polarities based on gate line driving frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common voltage supply line is added to apply common voltage to opposite electrodes, then liquid crystal cells can be driven, but aperture ratio is reduced
Solution Approach 1:
The patent removes the common voltage supply line from the liquid crystal display structure. Instead of providing a separate common voltage line to each liquid crystal cell, the invention uses the data lines themselves to provide both data voltage and common voltage, thereby eliminating the aperture ratio reduction caused by additional supply lines while maintaining proper liquid crystal cell operation
Solution Approach 2:
The data lines are made to serve dual functions: providing both data voltage to control liquid crystal switching and providing common voltage to the opposite electrodes. This multi-functional use of existing data lines eliminates the need for separate common voltage supply lines, preserving aperture ratio while ensuring reliable liquid crystal cell operation
2Object-affected harmful factors
If common voltage is adjusted to remove flicker caused by parasitic capacitance, then flicker is eliminated, but device complexity increases
Solution Approach 1:
The patent converts the previously harmful kickback voltage (caused by parasitic capacitance discharge) into a beneficial common voltage signal. By inverting the data voltage polarity simultaneously with common voltage polarity inversion, the kickback voltage becomes part of the driving mechanism rather than a disturbance requiring complex adjustment circuits to eliminate
3Reliability
If polarity inversion is implemented to reduce DC offset component, then liquid crystal deterioration is prevented, but afterimage is generated
Solution Approach 1:
The patent inverts the timing relationship between data voltage polarity inversion and common voltage polarity inversion. Instead of inverting both simultaneously or in the conventional sequence, the invention inverts data voltage polarity at a different timing relative to common voltage polarity, which prevents afterimage generation while maintaining DC offset reduction and liquid crystal durability
4Adaptability or versatility
If image signal swing width is increased to cover both positive and negative polarities, then liquid crystal cells can be driven with both polarities, but heat generation and current consumption increase
Solution Approach 1:
The patent uses symmetry about a middle voltage level to create equipotential driving conditions. By defining first and second image signals that are symmetrical with respect to a middle voltage (rather than using large positive and negative voltages), the invention achieves the necessary polarity coverage for driving liquid crystal cells while minimizing voltage swing width and thereby reducing heat generation and current consumption in the data driving circuit
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 approach increases the aperture ratio of liquid crystal cells, eliminates horizontal crosstalk and flicker, prevents afterimage generation, and reduces heat and current consumption in the data driving circuit while enabling high-voltage driving for faster response times.
Implementation Method 1
Each of the liquid crystal cells of the liquid crystal panel adjusts light transmittance of the liquid crystal based on an electric field formed by a potential difference between an image signal supplied to a corresponding data line and a common voltage applied to an opposite electrode
Data Source
AI summary
Disclosed herein are a liquid crystal display device which is capable of driving a liquid crystal using image signals supplied to two adjacent data lines, and a driving method thereof. The liquid crystal display device has a plurality of liquid crystal cells formed respectively in pixel areas defined by crossings of a plurality of gate lines and a plurality of data lines. Each of the liquid crystal cells includes a thin film transistor connected to any one of the gate lines and any one of the data lines, and a liquid crystal capacitor and a storage capacitor each formed between a data line adjacent thereto, among the data lines, and the thin film transistor. The thin film transistors of the liquid crystal cells are alternately arranged between and alternately connected to every two vertically adjacent ones of the gate lines along the gate lines.