RGBW Light Source Module Driving for Out-of-Gamut Color Display

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Solution Overview

Problem

Liquid crystal display (LCD) panels face issues with display quality, particularly in fully black images due to non-uniform liquid crystal molecule arrangements, leading to light leakage and decreased contrast ratio, which existing methods like local dimming and RGBW structures with boosted light sources do not adequately address for out-of-gamut colors.

Innovation Solution

A method of driving a display apparatus with a light source module that boosts the luminance of specific light-emitting blocks corresponding to out-of-gamut data in an RGBW structure, while correcting other gray-scales to maintain original luminance, allowing for the display of previously undisplayable out-of-gamut colors by adjusting duty ratios and peak currents of driving signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If local dimming is used to improve contrast ratio, then dark areas are improved, but out-of-gamut colors cannot be displayed

Engineering Contradiction:
Improvecontrast ratioVSAvoidcolor display capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by dividing the light source into multiple independently controllable light-emitting blocks, where each block can be individually boosted to display OOG colors while other blocks maintain normal operation. This allows selective enhancement of specific display regions without affecting the entire display, thus resolving the contradiction between maintaining good contrast ratio and enabling OOG color display.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If light source luminance is boosted to display OOG colors, then color gamut is improved, but power consumption increases

Engineering Contradiction:
Improvecolor gamutVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the light source into multiple light-emitting blocks that can be independently controlled. Only the blocks requiring OOG color display are boosted, while other blocks operate at normal luminance levels. This segmentation approach significantly reduces overall power consumption compared to boosting the entire light source, while still achieving the goal of displaying OOG colors in specific regions.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If RGBW structure is used with boosted light sources, then OOG colors can be displayed, but power consumption increases significantly

Engineering Contradiction:
ImproveOOG color displayVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic control of the light source by adjusting the luminance of individual light-emitting blocks based on the actual display content. The system dynamically determines which blocks need OOG color enhancement and boosts only those blocks when needed, rather than maintaining high luminance across all blocks continuously. This dynamic approach enables OOG color display while significantly reducing average power consumption.

Inventive Principle:
Principle #15Dynamics

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

Enhances display quality by enabling the display of out-of-gamut colors, improving contrast ratio and transmissivity, and reducing power consumption in the RGBW structure compared to traditional RGB structures.

Implementation Method 1

A luminance of a first light-emitting block corresponding to a first image block that includes the OOG data among a plurality of image blocks corresponding to the light-emitting blocks is boosted

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

When an electric field generated between the pixel electrode and the common electrode is applied to the liquid crystal layer, an arrangement of liquid crystal molecules of the liquid crystal layer is altered to change the optical transmissivity of the liquid crystal layer

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentEP2189968B1Method of driving a light source and a display apparatus for performing the method
Publication Date: 2014.07.16 SAMSUNG DISPLAY CO LTD
  • EP2189968B1 patent drawingFigure 1
  • EP2189968B1 patent drawingFigure 2~3
  • EP2189968B1 patent drawingFigure 4

AI summary

In method of individually driving a plurality of light-emitting blocks of a light source module providing light to a display panel including a unit pixel, luminance of a first light-emitting block corresponding to a first image block that includes an out of gamut (OOG) data among a plurality of image blocks corresponding to the light-emitting blocks is boosted. A second light-emitting block corresponding to a second image block that does not include the OOG data is driven so that the second light-emitting block has luminance corresponding to a representative gray-scale of the second image block.