Display Panel Common Voltage Control for Power Reduction
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Solution Overview
Problem
Conventional liquid crystal display devices using line inversion driving mode face high power consumption due to AC common voltage and unstable voltage levels at pixel electrodes, which are exacerbated by parasitic capacitors causing feed-through effects.
Innovation Solution
A display panel design incorporating a liquid crystal capacitor and storage capacitors, along with a control unit comprising transistors and additional storage capacitors, utilizes DC common voltages to stabilize pixel electrode voltages through a two-step voltage charging mechanism, reducing power consumption and achieving desired voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If AC common voltage is used in line inversion driving mode, then display arrays can be driven, but power consumption increases
Solution Approach 1:
The patent changes the common voltage from AC to DC, fundamentally altering the voltage parameter to reduce power consumption while maintaining display functionality through line inversion driving mode
Solution Approach 2:
The patent implements periodic line inversion where alternating lines are inverted in sequence, allowing DC common voltage to be used while maintaining the necessary voltage alternation for display operation
2Use of energy by stationary object
If DC common voltage is used, then power consumption is reduced, but video signal amplitude must be large and supply voltage must be high
Solution Approach 1:
The patent introduces a buffer transistor and storage capacitor as intermediary elements between the common voltage line and pixel electrode, allowing voltage level adjustment and reducing the need for high supply voltages
Solution Approach 2:
The patent uses the storage capacitor to change the voltage parameter at the pixel electrode by charging it through the buffer transistor, enabling DC common voltage operation with reduced supply voltage requirements
3Use of energy by stationary object
If DC common voltage is used, then power consumption is reduced, but voltage levels of pixel electrodes become unstable due to feed-through effect
Solution Approach 1:
The patent introduces a buffer transistor as an intermediary that controls the charging path of the storage capacitor, preventing direct feed-through effects from parasitic capacitors while maintaining voltage stability
Solution Approach 2:
The patent uses the storage capacitor to preliminarily store the desired voltage level, and the buffer transistor ensures this voltage is maintained without being affected by subsequent signal changes, preventing voltage instability
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
The solution effectively lowers power consumption and stabilizes pixel electrode voltages, allowing for operation at lower supply voltages without the need for large video signal amplitudes, thereby enhancing the longevity of liquid crystal molecules.
Implementation Method 1
The first storage capacitor is coupled between the pixel electrode and a second common line. The second storage capacitor is coupled between the first node and the second common line.
Implementation Method 2
The liquid crystal capacitor is coupled between a pixel electrode and a first common line.
Data Source
AI summary
A display panel is provided and includes a display unit and a control unit. The display unit is coupled to a data line and a first scan line. In the display unit, a liquid crystal capacitor is coupled between a pixel electrode and a first common line, and a storage capacitor is coupled between the pixel electrode and a second common line. The control unit receives first and second common voltages and is controlled by first and second control voltage signals and first and second scan signals which are respectively on the first scan line and a second scan line and driven sequentially. The control unit changes the voltage level of the second common line by a two-step manner according to the first and second common voltages. Through feed-through effect of the storage capacitor, the voltage level of the pixel electrode is changed to a desired level.