LCD Panel Test Backlight Unit with Chamber Cooling

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Solution Overview

Problem

Existing test devices for LCD panels face issues with the short lifetime of cold fluorescent lamps used as backlights, leading to frequent replacements and reduced effectiveness in detecting defects due to heat generation and brightness deviations.

Innovation Solution

A backlight unit with a chamber containing high-brightness LEDs, circulating fans, and optional refrigerant pipes or heat-radiating members to manage heat and ensure uniform light distribution, preventing brightness deviations and extending the backlight's lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a cold fluorescent lamp or cold cathode fluorescent lamp is used as the backlight, then the initial light output is sufficient, but the lifetime is rapidly decreased due to frequent blinking on and off

Engineering Contradiction:

Improvebacklight lifetimeVSAvoidbacklight reliability

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent transitions from cold fluorescent lamps to cold light emitting diodes (LEDs), changing the fundamental light source technology parameters. LEDs have inherently longer operational lifetime and can withstand frequent switching cycles without degradation, directly resolving the contradiction between initial light output and lifetime under frequent blinking conditions.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the backlight operates continuously, then the LCD panel can be tested without interruption, but heat is generated that decreases the backlight lifetime

Engineering Contradiction:

Improvetest continuityVSAvoidbacklight temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent introduces heat-radiating members (heat sinks) that convert the harmful heat generated by LED operation into a manageable thermal dissipation process. The heat sinks radiate heat away from the LEDs, allowing continuous operation for productivity while preventing temperature accumulation that would reduce backlight lifetime.

Inventive Principle:

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

3Illumination intensity

If the backlight generates heat during operation, then the LED can maintain high light output, but the heat causes damage to the PCB substrate and decreases system reliability

Engineering Contradiction:

Improvelight outputVSAvoidheat damage to PCB substrate

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces heat-radiating members as intermediary components between the LEDs and the PCB substrate. These heat sinks act as thermal mediators, absorbing heat from the LEDs and radiating it away, thereby protecting the PCB substrate from heat damage while allowing the LEDs to maintain high light output.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Illumination intensity

If the backlight is positioned close to the LCD panel for uniform illumination, then the light distribution is improved, but corner portions may not be effectively illuminated due to heat-related failures

Engineering Contradiction:

Improvelight distribution uniformityVSAvoidcorner illumination reliability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent uses heat-radiating members to convert the heat problem into a solution. By effectively radiating heat away from the LEDs, the system can maintain stable operation and consistent light output, ensuring reliable illumination of corner portions without the degradation that would otherwise occur due to heat accumulation.

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 solution extends the backlight's lifetime by managing heat and ensuring uniform light distribution, reducing the need for frequent replacements and enhancing defect detection accuracy in LCD panels.

Implementation Method 1

a backlight provided in the chamber to emit a light to an LCD panel positioned in the chamber

Methodology Applied

Scientific EffectLight emission from LEDs: Light Emitting Diode

Implementation Method 2

a plurality of circulating fans provided in the chamber to circulate air inside the chamber

Methodology Applied

Scientific EffectAir circulation for heat removal: Convection

Implementation Method 3

heat-radiating members or refrigerant pipes to manage heat

Methodology Applied

Scientific EffectHeat radiation: Thermal Radiation

Implementation Method 4

refrigerant pipes to manage heat

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentUS7753567B2Backlight unit for test device of LCD panel

Publication Date: 2010.07.13 LG DISPLAY CO LTD

AI summary

A backlight unit for a test device of an LCD panel is disclosed. The backlight unit includes: a chamber enclosing a predetermined space, the chamber being provided with a plurality of through holes formed around the chamber perimeter to allow air flow between the interior and exterior of the chamber; a backlight provided in the chamber to emit a light to an LCD panel positioned in the chamber; and a plurality of circulating fans provided in the chamber to circulate air inside the chamber.