Graphite Spreader and Coating Films for LCD Backlight Thermal Management

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Solution Overview

Problem

Conventional backlight units for large LCD devices face issues with heat dissipation due to the use of LEDs, leading to reduced operational reliability and increased temperatures, which can cause malfunctions.

Innovation Solution

Incorporating a graphite spreader with high thermal conductivity between the LEDs and the printed circuit boards, and using coating films to prevent graphite particles from falling and causing electrical issues, while also enhancing heat dissipation through the cover bottom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a graphite spreader is introduced to improve heat dissipation, then thermal conductivity is improved, but device complexity increases due to additional components

Engineering Contradiction:

Improveheat dissipationVSAvoidstructure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

A graphite spreader is introduced as an intermediary component between the LED module and the printed circuit board to enhance heat dissipation. The graphite spreader acts as a thermal mediator that conducts heat away from the LED chips more effectively than the original structure, resolving the heat dissipation issue without fundamentally redesigning the entire backlight unit.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material construction by combining the graphite spreader with the existing LED module and printed circuit board structure. This composite approach allows the high-thermal-conductivity graphite material to be integrated into the existing device architecture, improving heat dissipation while minimizing the increase in overall structural complexity.

Inventive Principle:

Principle #40Composite materials

2Reliability

If coating films are added to prevent graphite particle fall, then reliability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveoperational reliabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies a coating film layer that can be easily applied and removed, treating it as a disposable protective layer. This coating prevents graphite particles from falling and causing electrical shorts, while the simple nature of the coating allows for easy application during manufacturing and removal when needed, minimizing the impact on manufacturing complexity.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Use of energy by moving object

If direct type backlight units are used for large LCD devices, then light use efficiency is improved, but lamp lifespan decreases due to increased operating time and failure possibility

Engineering Contradiction:

Improvelight use efficiencyVSAvoidlamp lifespan

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent converts the harmful effect of heat generation by LEDs into a beneficial outcome by introducing the graphite spreader to manage thermal energy. The heat that would otherwise contribute to reduced LED lifespan and increased failure rates is now systematically conducted away from the LED chips, transforming a harmful thermal byproduct into a manageable thermal flow that extends component life.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 graphite spreader significantly improves heat dissipation, increasing the operational reliability of the backlight unit and minimizing temperature rises within the LCD device, while the coating films prevent electrical shorts and maintain structural integrity.

Implementation Method 1

a graphite spreader that dissipates heat from the light sources

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

first and second coating films that are attached to upper and lower surfaces of the graphite spreader, respectively, and extend outward from an edge of the graphite spreader such that the first and second coating films contact each other

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS7513652B2Backlight unit and liquid crystal display device using the same

Publication Date: 2009.04.07 LG DISPLAY CO LTD

AI summary

A backlight unit with a graphite spreader and coating films for sealing the graphite spreader to prevent fall of foreign substances from the graphite spreader is provided with a liquid crystal display device. The backlight unit includes a cover bottom, a plurality of light sources mounted on the cover bottom, a graphite spreader that dissipates heat from the light sources and is formed with at least one hole, and first and second coating films that are attached to upper and lower surfaces of the graphite spreader, respectively, and extend outward from an edge of the graphite spreader such that extent that the first and second coating films contact each other.