Common Voltage Generation Circuit for LCD Flicker Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional liquid crystal display (LCD) devices experience flicker phenomena due to asymmetry between positive-polarity and negative-polarity data voltages relative to the common voltage, which is difficult to quantify and control, leading to measurement errors and suboptimal display quality.

Innovation Solution

A common voltage generation circuit that includes a common voltage adjusting circuit, voltage detectors, and a comparator to adjust and optimize the common voltage, ensuring symmetry between positive and negative polarity data voltages, thereby reducing flicker and improving display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a digital variable resistor is used to enable inspector adjustment of flickering level, then the flicker phenomenon can be minimized, but the adjustment time varies depending on inspector's skill and quantitative control is less than satisfactory

Engineering Contradiction:

Improveflicker controlVSAvoidadjustment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements an automatic feedback control system where voltage detectors continuously monitor the potential differences between common voltage and data voltages, and a controller automatically adjusts the common voltage based on detected asymmetry. This eliminates manual adjustment by inspectors, providing consistent quantitative control without time loss to skill variation or repeated adjustments.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment through the automatic control circuit that detects voltage asymmetry and autonomously modifies the common voltage level. The circuit serves itself by using internal detection and control mechanisms rather than requiring external human intervention, thereby eliminating adjustment time variability.

Inventive Principle:

Principle #25Self-service

2Difficulty of detecting and measuring

If manual inspection is used to observe flickering level with naked eyes, then the flicker phenomenon can be detected, but measurement errors are introduced due to inspector's physical fatigue or ambient conditions

Engineering Contradiction:

Improveflicker detectionVSAvoidflicker measurement accuracy

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/visual inspection system with an electronic detection system. Voltage detectors and a controller objectively measure voltage asymmetry and automatically adjust parameters, eliminating human factors such as physical fatigue, ambient lighting conditions, and subjective judgment that compromise measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces voltage detectors and a controller as intermediary devices between the electrical signals and the assessment of flicker. These intermediaries provide precise, objective measurements of voltage asymmetry, removing the need for direct human visual observation and eliminating associated measurement errors.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If different common voltages are used for respective liquid crystal panels, then polarity inversion can be achieved, but the complexity of voltage generation increases

Engineering Contradiction:

Improvepolarity inversion capabilityVSAvoidvoltage generation circuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal common voltage generation system that can adapt to different polarity requirements through automatic detection and adjustment. Rather than requiring separate voltage generation circuits for different panels, a single intelligent system performs multiple functions: detecting voltage asymmetry, determining required polarity adjustments, and modifying common voltage accordingly, thereby simplifying the overall device architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8049692B2Common voltage generation circuit and liquid crystal display comprising the same

Publication Date: 2011.11.01 SAMSUNG DISPLAY CO LTD

AI summary

A common voltage generation circuit includes a common voltage adjusting circuit adjusting a level of a common voltage in response to a compensation signal and providing the adjusted common voltage to a liquid crystal panel, and a common voltage compensating circuit including a resistor producing potential differences between the adjusted common voltage and each of the positive and negative polarity data voltages, a first voltage detector detecting a potential difference between the adjusted common voltage and the negative polarity data voltage, a second voltage detector detecting a potential difference between the adjusted common voltage and the positive polarity data voltage, and a voltage comparator comparing output signals of the first and second voltage detectors and feeding the compensation signal back to the common voltage adjusting circuit.