Pixel Driving Method for LCD Blue Sub-Pixel Luminance

Solution Overview

Problem

Conventional liquid crystal displays experience poor image quality at oblique viewing angles due to excessive luminance reduction in blue sub-pixels, leading to a greenish tint, especially when displaying high gray scales.

Innovation Solution

A pixel driving method that adjusts voltages across different display regions of sub-pixels, ensuring the second voltage for blue sub-pixels is smaller than that of red or green sub-pixels when the first voltage exceeds a predetermined level, thereby minimizing luminance difference and reducing color washout.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional pixel circuits are used with equal voltages for all sub-pixels, then the device structure is simple, but the image quality deteriorates at oblique viewing angles due to excessive luminance reduction in blue sub-pixels

Engineering Contradiction:

Improvepixel circuit structureVSAvoidblue sub-pixel luminance

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by providing different voltages to different sub-pixels based on their specific characteristics. The blue sub-pixel receives a different voltage (second voltage) compared to red and green sub-pixels (third voltage) when the first voltage exceeds a predetermined level, compensating for the blue sub-pixel's excessive luminance reduction at oblique viewing angles.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the voltage assignment adaptive rather than fixed. The voltage provided to each sub-pixel dynamically changes based on the gray scale level (first voltage threshold) and viewing angle conditions, allowing the system to optimize image quality under different operating conditions.

Inventive Principle:

Principle #15Dynamics

2Illumination intensity

If different voltages are provided to compensate blue sub-pixel luminance, then the image quality improves at oblique viewing angles, but the device complexity increases due to additional voltage control circuits

Engineering Contradiction:

Improveimage quality at oblique viewing anglesVSAvoidvoltage control circuit

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing different voltages to different sub-pixels based on their specific characteristics. The blue sub-pixel receives a different voltage (second voltage) compared to red and green sub-pixels (third voltage) when the first voltage exceeds a predetermined level, compensating for the blue sub-pixel's excessive luminance reduction at oblique viewing angles.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the voltage assignment adaptive rather than fixed. The voltage provided to each sub-pixel dynamically changes based on the gray scale level (first voltage threshold) and viewing angle conditions, allowing the system to optimize image quality under different operating conditions.

Inventive Principle:

Principle #15Dynamics

3Illumination intensity

If high gray scale values are displayed, then the brightness increases, but the color accuracy deteriorates due to excessive luminance reduction in blue sub-pixels causing greenish tint

Engineering Contradiction:

Improvedisplay brightnessVSAvoidcolor accuracy

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by providing different voltages to different sub-pixels based on their specific characteristics. The blue sub-pixel receives a different voltage (second voltage) compared to red and green sub-pixels (third voltage) when the first voltage exceeds a predetermined level, compensating for the blue sub-pixel's excessive luminance reduction at oblique viewing angles.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements feedback by using the first voltage level as a reference to determine when to apply compensation. When the first voltage exceeds a predetermined level (indicating high gray scale), the system automatically adjusts the second and third voltages to maintain color accuracy, preventing the greenish tint that would otherwise occur.

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

This approach improves image quality at oblique viewing angles by reducing the concave curve of blue sub-pixel luminance, minimizing the difference between sub-pixel luminances, and preventing a greenish tint, especially for high gray scale values.

Implementation Method 1

a liquid crystal layer and a pixel circuit corresponding to each pixel... The liquid crystal pixel array is disposed close to the liquid crystal layer

Methodology Applied

Scientific EffectLiquid crystal orientation control: Liquid Crystals

Data Source

PatentUS9257076B2Pixel driving method and liquid crystal display implementing the same

Publication Date: 2016.02.09 AU OPTRONICS CORP

AI summary

A pixel driving method is adapted for a liquid crystal display. Each pixel includes a first sub-pixel and a second sub-pixel, in which the first sub-pixel and the second sub-pixel each includes a first display region and a second display region. The pixel driving method includes providing a first voltage to the first displaying region of the first sub-pixel and the second sub-pixel; providing a second voltage to the second displaying region of the first sub-pixel and a third voltage to the second displaying region of the second sub-pixel; and when the provided first voltage is larger than a predetermined voltage, providing the second voltage so that the provided second voltage is smaller than the provided third voltage.