Storage Electrode Line Voltage Inversion for LCD Power and Response
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges in reducing power consumption and improving response times while maintaining image definition, particularly due to the limitations of dynamic capacitance compensation methods which require additional computations and circuit changes, leading to increased manufacturing costs and difficulty in luminance representation, especially in high threshold voltage configurations like vertical alignment (VA) mode.
Innovation Solution
The implementation of a display device with a matrix of pixels, each comprising a switching element, liquid crystal capacitor, and storage capacitor, where storage signals with different voltage levels are applied to adjacent storage electrode lines in response to control signals, allowing for voltage inversion and maintenance periods to enhance pixel voltage range and luminance representation without significantly increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If dynamic capacitance compensation (DCC) method is used to improve response time, then charging time is reduced, but device complexity and manufacturing cost increase due to additional frame memory and driving circuits
Solution Approach 1:
The patent extracts the DCC computation function from the driving circuit and implements it through a simplified storage electrode line voltage inversion mechanism. Instead of using frame memory and complex DCC computation circuits, the invention applies voltage inversion directly to the storage electrode lines, achieving capacitance compensation with minimal additional circuitry.
Solution Approach 2:
The storage capacitor automatically compensates for voltage decay through the inversion of storage electrode line voltages. The system uses its own storage capacitors and voltage inversion mechanism to maintain pixel voltages without requiring external frame memory or complex control circuits, enabling self-service capacitance compensation.
2Use of energy by stationary object
If row inversion is used to reduce power consumption, then power consumption decreases, but the data voltage range becomes smaller making luminance representation difficult in high threshold voltage configurations
Solution Approach 1:
The patent adds a temporal dimension to voltage application by implementing frame-by-frame inversion of storage electrode line voltages. This allows the system to maintain row inversion for power savings while expanding the effective voltage range through alternating polarity, enabling adequate luminance representation even with limited data voltage ranges.
Solution Approach 2:
The storage electrode line voltages are inverted periodically for each frame, creating a periodic action that expands the voltage range over time. This periodic inversion allows the pixel to experience both positive and negative voltage extremes across frames, enabling full luminance representation while maintaining low power consumption through row inversion.
3Reliability
If the polarity of data voltage is inverted for each frame to prevent degradation, then device reliability improves, but response time increases due to the need to charge capacitor to target voltage
Solution Approach 1:
The patent applies preliminary action by pre-charging the storage capacitor during the gate signal pulse before the data voltage is fully established. The storage electrode line voltage inversion is also applied in advance of potential voltage decay, ensuring the pixel voltage is maintained without requiring slow charging through the liquid crystal capacitor alone.
Solution Approach 2:
The storage capacitor acts as an intermediary between the switching element and the liquid crystal capacitor. It provides a low-impedance path for rapid voltage establishment and maintains pixel voltage through stored charge, decoupling the reliability benefits of voltage inversion from the slow charging time of the liquid crystal capacitor.
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 reduces power consumption, improves response times, and enhances image definition by broadening the pixel voltage range, allowing for better luminance representation without the need for significant power consumption increases, even in high threshold voltage configurations.
Implementation Method 1
a liquid crystal layer having an anisotropy dielectric disposed between the display panels
Implementation Method 2
Because of the slow response rate of liquid crystal molecules, it takes time to charge a liquid crystal capacitor up to a target voltage
Data Source
AI summary
In one embodiment of the invention, a display device includes a plurality of gate lines transferring gate signals, a plurality of data lines transmitting data voltages, a plurality of storage electrode lines transferring storage signals, and a plurality of pixels arranged in a matrix, each pixel comprising a switching element connected to a gate line and a data line, a liquid crystal capacitor connected to the switching element and a common voltage, and a storage capacitor connected to the switching element and a storage electrode line. The display device may further include a plurality of signal generating circuits generating the storage signals, wherein the signal generating circuit is connected to a k-th storage electrode line, where k is a natural number.