Display Device Grayscale Masking for Color Uniformity

Solution Overview

Problem

Light emitting display devices face challenges in low-grayscale expression, leading to color unevenness and image sticking due to luminance deviations between light emitting elements, which affect color accuracy and uniformity.

Innovation Solution

A light emitting display device and method that utilize an image processor to generate and apply a grayscale reproduction mask based on a threshold value and cumulative usage of each light emitting element, adjusting subpixel positions and outputting image data to improve color accuracy and reduce lifespan deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If light emitting display devices use low current during representation of low grayscales, then power consumption is reduced, but low grayscale expression decreases and color unevenness occurs

Engineering Contradiction:

Improvepower consumptionVSAvoidlow grayscale expression

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent segments the grayscale representation into two distinct methods: for grayscales above the threshold value, conventional low-current driving is used to save power; for grayscales at or below the threshold value, a different approach using higher current or alternative driving methods is employed to maintain adequate grayscale expression. This segmentation allows the system to optimize power consumption in the majority of cases while ensuring minimum quality standards are met for low grayscale regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a threshold value parameter that separates two different operating regimes. By changing the driving parameters (current level, voltage, or other electrical characteristics) based on whether the grayscale value is above or below this threshold, the system can adaptively optimize both power consumption and display quality. The threshold value itself becomes a controllable parameter that can be adjusted based on content characteristics, display conditions, or user preferences.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If light emitting display devices use low current during representation of low grayscales, then power consumption is reduced, but color accuracy decreases due to luminance deviation

Engineering Contradiction:

Improvepower consumptionVSAvoidcolor accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent segments the grayscale representation into two distinct methods: for grayscales above the threshold value, conventional low-current driving is used to save power; for grayscales at or below the threshold value, a different approach using higher current or alternative driving methods is employed to maintain adequate grayscale expression.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a threshold value parameter that separates two different operating regimes. By changing the driving parameters (current level, voltage, or other electrical characteristics) based on whether the grayscale value is above or below this threshold, the system can adaptively optimize both power consumption and display quality.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of moving object

If light emitting elements are used with different cumulative usage, then lifespan deviations occur, but image sticking is caused by luminance deviation

Engineering Contradiction:

ImprovelifespanVSAvoidimage sticking

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary compensation actions by identifying light emitting elements with high cumulative usage before they fail, and proactively adjusting their driving parameters or replacing them. This preliminary intervention prevents the development of luminance deviations that would lead to image sticking, maintaining display quality throughout the element's operational life.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism that continuously monitors the cumulative usage and performance characteristics of light emitting elements. Based on this feedback, the system adjusts driving parameters or triggers replacement decisions to maintain uniform luminance across all elements, preventing image sticking caused by lifespan deviations.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11436969B2Light emitting display device and method for driving same

Publication Date: 2022.09.06 LG DISPLAY CO LTD

AI summary

The present disclosure relates to a display device and a method for driving the same which can improve color unevenness in a low-grayscale (low-luminance) area and improve color accuracy and grayscale expression, and an image processor of a display device according to an embodiment identifies a low-grayscale area less than a threshold value according to an input maximum luminance and applies a grayscale reproduction mask thereto to reproduce a luminance of the low-grayscale area as a combination of the threshold value and a minimum value.