LCD Common Voltage Correction for Power Reduction
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Solution Overview
Problem
LCD devices face increased power consumption and manufacturing costs due to the need for higher input voltages when liquid crystal driving voltage increases, limiting the use of existing high-voltage source driving ICs and requiring frequent replacements.
Innovation Solution
The implementation of a data driver and timing controller system that adjusts the common voltage and data voltage to reduce power consumption, allowing the use of a single voltage for both liquid crystal driving and input, and employing charge pumping for positive polarity data voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the liquid crystal driving voltage is increased to improve display performance, then the luminance and image quality are improved, but the input voltage required doubles and power consumption increases
Solution Approach 1:
The patent changes the voltage reference parameter by introducing a correction common voltage that shifts the voltage baseline. Instead of using symmetric positive/negative data voltages around a zero reference, the system uses unipolar data voltages referenced to a corrected common voltage level, thereby reducing the peak-to-peak voltage swing while maintaining the same liquid crystal driving effect.
Solution Approach 2:
The patent creates a corrected version of the common voltage signal through the correction common voltage generator. This copied and modified reference voltage signal is then used to generate data voltages that achieve the same liquid crystal modulation effect with reduced amplitude, thereby lowering power consumption while maintaining luminance performance.
2Illumination intensity
If high-voltage source driving ICs are used to support higher liquid crystal driving voltages, then the display performance is improved, but the manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent introduces a correction common voltage generator as an intermediary component between the common voltage source and the data driver. This intermediary generates a shifted reference voltage that enables the data driver to produce reduced-amplitude data voltages, thereby allowing standard low-voltage ICs to achieve high-voltage driving performance without requiring expensive high-voltage specialized ICs.
Solution Approach 2:
The correction common voltage generator enables a single data driver IC to serve multiple voltage requirements. By dynamically adjusting the reference voltage level, the same hardware infrastructure can support both standard and enhanced luminance modes, eliminating the need for separate high-voltage IC designs and reducing overall system complexity.
3Illumination intensity
If high-voltage source driving ICs are used to support higher liquid crystal driving voltages, then the display performance is improved, but the manufacturing cost increases
Solution Approach 1:
The correction common voltage generator acts as a cost-effective intermediary that enables standard, mass-produced data driver ICs to achieve high-voltage driving capability. This approach avoids the need for expensive, specialized high-voltage ICs, thereby reducing manufacturing costs while maintaining improved display performance.
Solution Approach 2:
By changing the reference voltage parameter through the correction common voltage, the system enables existing low-voltage IC designs to be used for high-voltage applications. This parameter transformation allows manufacturers to continue using established, cost-effective IC production processes rather than investing in new high-voltage IC manufacturing lines.
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 enables high-voltage driving with reduced power consumption by the data driver, allowing the same voltage to be used for liquid crystal driving and input, and improves luminance differences through scanning driving, while decreasing the analog unit's power consumption by about 50%.
Implementation Method 1
employing charge pumping for positive polarity data voltage generation
Data Source
AI summary
Disclosed is an LCD device. The LCD device comprises a panel, a data driver configured to output a data voltage to a data line; a gate driver configured to sequentially output a scan signal to a plurality of gate lines, a common electrode formed at the panel in correspondence with each of the pixels, a common voltage generator configured to generate a common voltage to be supplied to the common electrode, a timing controller configured to output a first selection signal or a second selection signal, and a selector configured to output a correction common voltage corresponding to a negative liquid crystal driving voltage or the common voltage to the common electrode by using the scan signal, the first selection signal, or the second selection signal.