Liquid Crystal Display Boosting Capacitance Circuit
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Solution Overview
Problem
Conventional liquid crystal display devices for portable equipment face challenges in reducing power consumption, particularly with the transition from common AC driving to dot inversion driving, which requires high breakdown strength for the driver circuit, making it difficult to achieve low power consumption.
Innovation Solution
A liquid crystal display device with a driver circuit that includes a boosting capacitance and switching elements to supply video signals to pixel electrodes, allowing for voltage boosting or dropping, thereby setting the pixel electrode voltage fixed times larger than the video signal, using a first and second switching element controlled by scanning and boosting scanning signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dot inversion driving is used to reduce common voltage fluctuation, then display quality is improved, but driver circuit breakdown strength requirement increases and power consumption increases
Solution Approach 1:
The patent inverts the conventional approach by using common AC driving (where common voltage changes polarity) instead of dot inversion driving. This reverse approach, combined with voltage boosting/correcting circuits, achieves both low power consumption and adequate display quality without requiring high breakdown strength in the driver circuit.
Solution Approach 2:
The patent changes the voltage parameters by introducing boosting capacitances that multiply the video signal voltage (e.g., 2x boosting). This parameter change allows the system to achieve sufficient pixel electrode voltage for good display quality while operating the driver circuit at lower voltages, reducing power consumption.
2Use of energy by moving object
If common AC driving is used to reduce driver circuit breakdown strength requirement, then power consumption is reduced, but common voltage fluctuates and display quality deteriorates
Solution Approach 1:
The patent introduces voltage boosting/correcting circuits as intermediary components between the driver circuit and pixel electrodes. These circuits correct the common voltage fluctuations caused by common AC driving, thereby maintaining display quality while allowing the system to operate at lower power consumption levels.
Solution Approach 2:
The patent applies voltage boosting (e.g., 2x multiplication) to compensate for common voltage fluctuations. By changing the voltage parameter through boosting capacitances, the system maintains adequate pixel electrode voltages for good display quality while operating in low power consumption common AC driving mode.
3Use of energy by moving object
If voltage boosting is implemented to achieve fixed times larger pixel electrode voltage, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The patent merges the voltage boosting function with the existing pixel circuit structure by integrating boosting capacitances into the pixel electrode configuration. This combining approach achieves voltage multiplication for power consumption reduction while minimizing the increase in device complexity through shared circuit elements.
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 low power consumption by allowing arbitrary setting of the boosting capacitance to control the pixel electrode voltage, reducing power consumption while maintaining high resolution, and is applicable to both IPS and vertical-electric-field method type liquid crystal display panels.
Implementation Method 1
a boosting capacitance which includes a first capacitance electrode and a second capacitance electrode electrically connected to the pixel electrode
Data Source
AI summary
The present invention provides a liquid crystal display device used in miniaturized portable equipment which exhibits favorable display quality while decreasing a load applied to a driver circuit which supplies a video signal line to pixel electrodes. In a liquid crystal display device which includes liquid crystal display elements and a liquid crystal driving circuit, a boosting circuit is provided to a pixel portion. The boosting circuit, after writing a video signal in a pixel electrode and one electrode of a boosting capacitance, brings the pixel electrode into a floating state. Then, by applying the video signal to another electrode of the boosting capacitance, a voltage of the pixel electrode is boosted or dropped.