Common Voltage Control Circuit for Display Panel Image Sticking

Solution Overview

Problem

Liquid crystal display devices experience image sticking due to polarization and ionic impurity accumulation, leading to persistent traces of static images, which is difficult to resolve through material improvements given the long development cycle and high cost of new liquid crystal materials.

Innovation Solution

A common voltage control circuit and method that includes a temperature sensing circuit and a voltage adjusting circuit to dynamically adjust the common voltage based on ambient temperature, using a microcontroller and digital potentiometer to minimize flicker and adjust the degree of liquid crystal molecule rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid crystal material purity is improved to reduce ionic impurities, then image sticking is reduced, but development cost and time increase significantly

Engineering Contradiction:

Improveimage sticking preventionVSAvoidmaterial development cycle

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the common voltage parameter dynamically based on temperature to prevent image sticking. By adjusting the common voltage according to temperature conditions, the system prevents ionic impurity accumulation and polarization effects without requiring material improvements, thus resolving the contradiction between reliability and development time.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the material-based solution (improving liquid crystal purity) with a control-based solution (adjusting common voltage). This substitution avoids the long material development cycle while achieving the same goal of preventing image sticking through electrical parameter control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If liquid crystal material purity is improved to reduce ionic impurities, then image sticking is reduced, but material cost increases significantly

Engineering Contradiction:

Improveimage sticking preventionVSAvoidmaterial cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the common voltage parameter dynamically based on temperature to prevent image sticking. By adjusting the common voltage according to temperature conditions, the system prevents ionic impurity accumulation and polarization effects without requiring material improvements, thus resolving the contradiction between reliability and development time.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the material-based solution (improving liquid crystal purity) with a control-based solution (adjusting common voltage). This substitution avoids the long material development cycle while achieving the same goal of preventing image sticking through electrical parameter control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If common voltage is increased to improve image quality, then liquid crystal molecule control is enhanced, but flicker increases at certain temperatures

Engineering Contradiction:

Improveliquid crystal control precisionVSAvoidflicker

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent implements dynamic adjustment of the common voltage based on temperature conditions. Rather than using a fixed high voltage that causes flicker, the system continuously adapts the common voltage to match temperature conditions, maintaining precise liquid crystal control while eliminating flicker at different temperatures.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses temperature sensing to provide feedback for adjusting the common voltage. This feedback mechanism ensures that the common voltage is optimized for each temperature condition, preventing flicker while maintaining effective liquid crystal molecule control.

Inventive Principle:

Principle #23Feedback

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 reduces image sticking by adjusting the common voltage according to temperature, ensuring the smallest flicker and optimal liquid crystal molecule control, thereby preventing image retention across varying temperatures.

Implementation Method 1

The temperature sensing circuit includes a thermistor. The voltage adjusting circuit includes a resistance voltage divider.

Methodology Applied

Scientific EffectTemperature sensing: Thermistor

Implementation Method 2

The resistance voltage divider is a fixed resistor.

Methodology Applied

Scientific EffectElectrical resistance adjustment: Electrical Resistance

Data Source

PatentUS10867573B2Common voltage control circuit and method, display panel and display device

Publication Date: 2020.12.15 BEIJING SMART AERO DISPLAY TECH CO LTD

AI summary

Provided in the embodiments of the disclosure are a common voltage control circuit and method, a display panel and a display device. The control circuit includes a temperature sensing circuit and a voltage adjusting circuit. The temperature sensing circuit is configured to sense the ambient temperature. The voltage adjusting circuit is coupled to the temperature sensing circuit and the common electrode, and is configured to provide a corresponding common voltage to the common electrode based on a temperature signal from the temperature sensing circuit. According to the embodiments of the present disclosure, the common voltage may be changed according to the ambient temperature to improve the image sticking.