Backlight Module With Inverted Dual External Electrodes

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Solution Overview

Problem

Conventional external electrode fluorescent lamps (EEFLs) in backlight modules face issues with high start voltage and current leakage, leading to reduced luminance and increased heat, which affects the performance of the backlight module.

Innovation Solution

The proposed backlight module design incorporates a configuration with two lamps and two external electrodes, where the voltage signals applied to the lamps are inverted, allowing for lower operating voltages and reduced power consumption, and includes high-impedance circuits and phase differences to optimize voltage distribution and luminance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional external electrode fluorescent lamps are used in backlight modules, then the lamps can provide illumination, but the start voltage is too high causing current leakage and reduced luminance

Engineering Contradiction:

ImproveluminanceVSAvoidcurrent leakage

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent divides the single high-voltage external electrode system into two separate low-voltage external electrodes, each connected to independent voltage sources. This segmentation allows each electrode to operate at lower voltage levels, preventing current leakage while maintaining illumination capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent inverts the conventional single-electrode configuration by using two external electrodes with inverted voltage signals. Instead of one electrode receiving high voltage, two electrodes receive inverted low-voltage signals, fundamentally changing the electrical configuration to eliminate current leakage.

Inventive Principle:

Principle #13The other way round (Inversion)

2Illumination intensity

If the brightness of CCFL is increased to meet LCD requirements, then the illumination quality improves, but the heat generation increases significantly

Engineering Contradiction:

ImprovebrightnessVSAvoidheat generation

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The patent changes the electrical parameters by switching from high-voltage single-electrode operation to low-voltage dual-electrode operation with inverted signals. This parameter change enables achieving required brightness while operating at lower voltage levels, thereby reducing heat generation.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If external electrode fluorescent lamps are used to reduce heat, then the operating temperature decreases, but the working voltage becomes too high causing current leakage

Engineering Contradiction:

Improveoperating temperatureVSAvoidcurrent leakage

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent segments the high-voltage operation into two low-voltage operations with external electrodes. Each external electrode operates independently at lower voltage, maintaining the heat-reduction benefit while eliminating the current leakage problem associated with high working voltage.

Inventive Principle:

Principle #1Segmentation

4Device complexity

If conventional EEFL configuration is used, then the lamp structure is simple, but the luminance is reduced due to outer electrode surrounding the lamp tube

Engineering Contradiction:

Improvelamp structureVSAvoidluminance

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The patent inverts the conventional EEFL configuration by placing two external electrodes outside the lamp tube instead of surrounding it with one outer electrode. This inverted configuration, combined with inverted voltage signals, improves luminance while maintaining structural simplicity.

Inventive Principle:

Principle #13The other way round (Inversion)

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 effectively reduces the start voltage and current leakage, enhancing the luminance and operational efficiency of the backlight module while minimizing heat generation and power consumption.

Implementation Method 1

the first voltage signal and the second voltage signal are inverted

Methodology Applied

Scientific EffectInverted voltage signals:

Implementation Method 2

the first terminal of the first external electrode electrically couples to the second voltage source and the first terminal of the second external electrode electrically couples to the first voltage source

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS8115400B2Backlight module

Publication Date: 2012.02.14 AU OPTRONICS CORP

AI summary

Backlight module is disclosed. The backlight module includes a first lamp, a first voltage source, a second lamp, a second voltage source, a first external electrode, and a second external electrode. Both the first and the second voltage sources have a first terminal and a second terminal. The first voltage source is used to output a first voltage signal and electrically couples to the first terminal of the first lamp. The second voltage source is used to output a second voltage signal and electrically couples to the first terminal of the second lamp. Both the first external electrode and the second external electrode have a first terminal and a second terminal. The first terminal of the first external electrode electrically couples to the second voltage source and the first terminal of the second external electrode electrically couples to the first voltage source, wherein the first voltage signal and the second voltage signal are inverted.