Two-Sided LED Backlight Module with Flexible Circuit Board

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Solution Overview

Problem

Conventional two-sided backlight modules using cold cathode fluorescent lamps (CCFLs) face issues such as high cost, environmental pollution, and increased thickness due to the need for multiple LED light bars and metal bases for heat dissipation, which complicates manufacturing and assembly.

Innovation Solution

A flexible circuit board with a conductive and insulating layer supports light emitting diodes on both sides, connected via a single conductive layer, and includes a metal support member with openings for interlaced placement and thermal pads for efficient heat dissipation, reducing the need for additional components and thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional CCFLs are used as light sources in two-sided backlight modules, then two-sided lighting effect is achieved, but manufacturing cost increases and environmental pollution occurs due to mercury content

Engineering Contradiction:

Improvetwo-sided lighting effectVSAvoidenvironmental pollution

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive and environmentally harmful CCFLs with LEDs, which are cheaper, longer-lasting, and environmentally friendly. Multiple LED strips are arranged on both sides of a substrate to achieve two-sided lighting without using mercury-containing materials.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the light source parameter from CCFL to LED, transforming the illumination system to achieve similar two-sided lighting效果 while eliminating environmental pollution and reducing cost.

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If double LED light bars with aluminum or fiber glass bases are used to achieve two-sided backlight, then lighting effect is improved, but manufacture cost increases and assembly thickness increases

Engineering Contradiction:

Improvetwo-sided backlight effectVSAvoidassembly structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent merges the substrate function with the heat dissipation function by using a single substrate that supports LED strips on both sides. This eliminates the need for separate aluminum or fiber glass bases, reducing assembly complexity and thickness while maintaining structural integrity and heat dissipation capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The substrate serves multiple functions: supporting LED strips, providing structural stability, and dissipating heat. This multi-functional design replaces the conventional separate components (bases, mounting structures), simplifying the overall assembly.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Temperature

If metal plate is disposed between two LED light bars to enhance heat dissipation, then heat dissipation efficiency is improved, but total assembly thickness increases

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidassembly thickness

Core Design Contradiction:

TemperatureVSLength of stationary object

Solution Approach 1:

The patent combines the heat dissipation function with the substrate itself, eliminating the need for a separate metal plate. The substrate is designed with sufficient thermal conductivity and surface area to dissipate heat from LEDs on both sides, thereby reducing assembly thickness while maintaining effective heat management.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the heat dissipation function from a separate metal plate component and integrates it into the substrate, removing the extra thickness contributor while preserving the essential heat dissipation capability.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This design achieves a two-sided lighting effect with reduced manufacturing costs and assembly thickness while providing effective heat dissipation and improved light distribution, overcoming the limitations of CCFLs.

Implementation Method 1

a plurality of light emitting diodes respectively disposed on two sides of the flexible circuit board and electrically connected to the conductive layer of the flexible circuit board for emitting light towards the two sides of the flexible circuit board

Methodology Applied

Scientific EffectLight emitting diode: Light Emitting Diode

Implementation Method 2

at least one thermal pad disposed between the conductive layer of the flexible circuit board and the light emitting diode

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9087463B2Backlight module and display device with two-sided light emitting structure

Publication Date: 2015.07.21 WISTRON CORP

AI summary

A backlight module includes a flexible circuit board. The flexible circuit board includes a conductive layer and an insulating layer covering the conductive layer. The backlight module further includes a plurality of light emitting diodes respectively disposed on two sides of the flexible circuit board and electrically connected to the conductive layer of the flexible circuit board for emitting light towards the two sides of the flexible circuit board.