Backlight Unit LED Pre-heating for Fast CCFL Startup

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Solution Overview

Problem

Conventional liquid crystal display (LCD) devices face delays in displaying images due to the time required for cold cathode fluorescent lamps (CCFLs) to warm up, leading to inefficient startup and suboptimal initial image quality.

Innovation Solution

Incorporating a light emitting diode (LED) under a light guide holder within the backlight unit, which is positioned to concentrate light onto the CCFLs, helping to activate the gas inside the lamps quickly, thereby reducing startup time and improving image quality by ensuring rapid illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If cold cathode fluorescent lamps (CCFLs) are used as the backlight light source, then the LCD device can provide sufficient illumination, but the startup time is delayed due to the warm-up time required for the lamps

Engineering Contradiction:

Improvebacklight illuminationVSAvoidstartup time

Core Design Contradiction:

Illumination intensityVSLoss of time

Solution Approach 1:

A light emitting diode (LED) is disposed under each CCFL to emit light before the CCFL is activated. This preliminary action pre-heats the gas inside the CCFL, reducing the warm-up time when the CCFL is subsequently turned on. The LED serves as a pre-conditioning device that prepares the CCFL for faster activation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The LED acts as an intermediary device between the power supply and the CCFL. Instead of directly switching the CCFL on (which requires long warm-up time), the LED first emits light to activate the gas in the CCFL, then the CCFL is turned on to provide the main illumination. This intermediary approach resolves the contradiction between sufficient illumination and fast startup.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If CCFLs are used in the backlight unit, then uniform illumination can be achieved, but the initial image quality is suboptimal due to delayed illumination

Engineering Contradiction:

Improveuniform illuminationVSAvoidinitial image quality

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The LED emits light before the CCFL is activated, performing a preliminary action that ensures the gas inside the CCFL is ready for immediate effective illumination. This preliminary lighting action eliminates the period of suboptimal image quality that occurs during CCFL warm-up, ensuring reliable image display from the moment the display is turned on.

Inventive Principle:

Principle #10Preliminary 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

This solution enables faster startup of the backlight, enhancing image quality by ensuring immediate and uniform illumination of the LCD panel, thus addressing the delay in displaying images.

Implementation Method 1

a light emitting diode disposed under a light guide holder

Methodology Applied

Scientific EffectLight emitting diode (LED): Light Emitting Diode

Implementation Method 2

cold cathode fluorescent lamps (CCFLs)

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS7777830B2Backlight unit and liquid crystal display module using the same

Publication Date: 2010.08.17 LG DISPLAY CO LTD

AI summary

A backlight unit includes a lamp, a bottom frame disposed under the lamp, the bottom frame having a first hole corresponding to the lamp, a light guide holder inserted into the first hole, and a light emitting diode disposed under the light guide holder.