Module-Type Backlight Unit With Local Dimming

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Solution Overview

Problem

Commercial display apparatuses, particularly LCDs, face issues with image clarity due to inadequate backlighting and excessive heat generation, which affect the quality and efficiency of the display.

Innovation Solution

A module-type backlight unit incorporating light guide panels with optical patterns and local dimming methods to improve light distribution and reduce power consumption, featuring a matrix arrangement of optical assemblies with independently controlled LEDs to enhance image contrast and reduce thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional backlight units are used, then the display apparatus can be manufactured, but the displayed image is not clear and excessive heat is generated

Engineering Contradiction:
Improveimage clarityVSAvoidheat generation
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The backlight unit is divided into multiple independently controllable light guide panels arranged in a matrix pattern. Each panel can be controlled separately to provide local dimming, improving image clarity and contrast while distributing heat generation across multiple segments rather than concentrating it in a single backlight unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local dimming by dividing the backlight into multiple zones that can be independently adjusted in brightness. This allows different regions of the display to have different illumination intensities, enhancing image quality in bright areas while reducing power consumption and heat generation in darker areas.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If the backlight unit uses more LEDs for better illumination, then image quality improves, but power consumption increases

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

Solution Approach 1:

The backlight unit employs dynamic local dimming control where the illumination intensity of each light guide panel can be independently adjusted based on the displayed content. This dynamic adjustment optimizes power consumption by reducing light output in areas where full illumination is not needed, while maintaining high image quality in areas that require it.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements impulsive driving methods where LEDs are activated in periodic pulses rather than continuously. This periodic activation reduces average power consumption while maintaining perceived brightness through persistence of vision, effectively decoupling peak illumination intensity from average power consumption.

Inventive Principle:
Principle #19Periodic 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 improves image clarity and contrast by optimizing light distribution and power usage, allowing for a thinner display apparatus with reduced power consumption and enhanced local dimming effects.

Implementation Method 1

a light guide panel having a light incident part and a light emitting part

Methodology Applied
Scientific EffectLight guidance: Waveguide (optics)

Implementation Method 2

an optical pattern provided to the light guide panel prevents interference between sub blocks

Methodology Applied
Scientific EffectLight refraction and dispersion: Refraction

Data Source

PatentEP2460049B1Backlight unit and display apparatus including the same
Publication Date: 2017.05.17 LG ELECTRONICS INC
  • EP2460049B1 patent drawingFigure 1
  • EP2460049B1 patent drawingFigure 2
  • EP2460049B1 patent drawingFigure 3~5

AI summary

A back-light unit including a plurality of substrates, a plurality of light sources respectively disposed on the plurality of substrates and configured to emit light, and N (N > 2) light guide panels respectively disposed adjacent to the plurality of light sources, a corresponding light guide panel including a light incidence part having a light incidence surface for receiving light emitted from a corresponding light source, and a light emission part for emitting the received incident light. Further, the corresponding light guide panel includes protruding surface patterns protruding from an upper surface the light emission part.