Luminance Control Device for Display Panel Uniformity

Solution Overview

Problem

Organic light emitting display devices experience luminance unevenness over time due to deterioration of organic light emitting diodes and driving transistors, leading to reduced display quality.

Innovation Solution

A luminance control device that divides the display panel into blocks, calculates a block reference current, and adjusts the data voltage based on a scaling factor derived from the target current and sensing current to maintain uniform luminance across the panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the display device operates for extended periods, then the organic light emitting diode and driving transistor deteriorate, but luminance uniformity across the panel worsens

Engineering Contradiction:

Improvedisplay device operating timeVSAvoidluminance uniformity

Core Design Contradiction:

Duration of action of stationary objectVSIllumination intensity

Solution Approach 1:

The display panel is divided into multiple blocks, and luminance compensation is performed independently for each block. This segmentation allows localized correction of luminance variations caused by deterioration, maintaining overall uniformity even after extended operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system measures the actual luminance output of each block and uses this feedback to calculate compensation values. These compensation values are then applied to adjust the driving current, creating a closed-loop control system that maintains luminance uniformity over time.

Inventive Principle:

Principle #23Feedback

2Illumination intensity

If the display panel is divided into multiple blocks for luminance control, then luminance uniformity improves, but device complexity increases

Engineering Contradiction:

Improveluminance uniformityVSAvoidluminance control structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The display panel is divided into multiple blocks, and luminance compensation is performed independently for each block. This segmentation allows localized correction of luminance variations caused by deterioration, maintaining overall uniformity even after extended operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The luminance controller performs multiple functions: it divides the panel into blocks, measures luminance in each block, calculates compensation values, and adjusts driving currents. This multi-functional approach consolidates complex operations into a single control unit, managing complexity while achieving uniformity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If block reference current is calculated based on sensed block current, then luminance compensation accuracy improves, but measurement and calculation complexity increases

Engineering Contradiction:

Improveluminance measurement accuracyVSAvoidcalculation system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system measures the actual luminance output of each block and uses this feedback to calculate compensation values. These compensation values are then applied to adjust the driving current, creating a closed-loop control system that maintains luminance uniformity over time.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The luminance controller pre-calculates reference currents for each block based on sensed currents and stored reference values. This preliminary calculation prepares compensation data in advance, reducing real-time computational complexity while maintaining measurement precision.

Inventive Principle:

Principle #10Preliminary action

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 enhances display quality by reducing luminance differences between blocks, thereby improving luminance uniformity and extending the lifespan of the display device.

Implementation Method 1

a current sensor configured to sense the block current and the sensing current of each of the plurality of blocks

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS11107418B2Luminance control device, display device including the same, and method of driving the same

Publication Date: 2021.08.31 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display panel including pixels, a luminance controller that divides the display panel into blocks based on coordinate information, calculates a block reference current based on a block current sensed in each of the blocks when reference images are sequentially displayed on the blocks, calculates a target current based on the block reference current and a block load of each of the blocks based on input image data, and calculates a scaling factor based on the target current and a sensing current sensed in each of the blocks when an input image corresponding to the input image data is displayed on the display panel, and a data driver that generates a data voltage corresponding to the input image data and supplies the data voltage to the pixels by adjusting a voltage level of the data voltage based on the scaling factor.