Backlight Unit Fault Compensation via Movable LEDs

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Solution Overview

Problem

Display devices face issues with non-uniform light distribution due to faulty light sources in the backlight unit, leading to uneven image quality as some pixels appear brighter or darker than intended.

Innovation Solution

The method involves detecting faulty light sources and using actuators to move nearest neighbor light sources closer to the faulty ones and adjust their intensity to compensate for the faulty light, ensuring uniform light distribution across the screen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a faulty light source is detected and compensated by adjusting nearby LEDs, then image quality is improved, but device complexity increases due to additional actuators and control mechanisms

Engineering Contradiction:
Improveimage qualityVSAvoidbacklight unit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backlight unit performs self-diagnosis and self-repair by automatically detecting faulty light sources and compensating for their failure. The system uses a camera to detect dark pixels, identifies failed LEDs, and automatically adjusts working LEDs to compensate, eliminating the need for external intervention or complex manual repair mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes operational parameters of working light sources dynamically. When a faulty LED is detected, the controller increases the drive current or duty cycle of neighboring working LEDs to compensate for the lost light output, thereby maintaining uniform illumination without physical restructuring.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If the intensity of working light sources is increased to compensate for faulty sources, then light distribution uniformity is improved, but energy consumption increases

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

Instead of uniformly increasing the intensity of all light sources, the system applies intensity compensation only to working LEDs adjacent to detected faulty sources. This localized approach maintains uniformity in affected regions while minimizing overall energy consumption by leaving other LEDs at normal operating levels.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system applies partial compensation by adjusting only the necessary subset of working LEDs near faulty sources rather than all LEDs. This selective adjustment achieves the required uniformity while avoiding excessive energy consumption that would result from globally increasing all light source intensities.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3435366B1Method of controlling a backlight unit, a backlight unit and a display device and camera system
Publication Date: 2021.08.25 VESTEL ELEKTRONIK SANAYI & TICARET ANONIM SIRKETI
  • EP3435366B1 patent drawingFigure 1~2
  • EP3435366B1 patent drawingFigure 3A~3C
  • EP3435366B1 patent drawingFigure 4

AI summary

There is provided a method of controlling a backlight unit (31) of a display device (30). The backlight unit (31) comprises a plurality of light sources for illuminating a screen (43) of the display device (30). The method comprises detecting a faulty light source (32) amongst the plurality of light sources. In response thereto, at least one other light source (33) is moved from a first position to a second position to allow the at least one other light source (33) to compensate for the faulty light source (32). A backlight unit (31) having a plurality of controllably movable light sources is provided for performing the method. A system is also provided for controlling the location of the controllably movable light sources in the backlight unit (31) of the display device (30).