Backlight Unit Light Guide Plate Stabilization

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Solution Overview

Problem

Liquid crystal display devices suffer from the 'white spot' issue due to light scattering caused by scratches or breakage on the light guide plate or reflective sheet, leading to deterioration in display quality, especially in edge-type backlight units where the light guide plate is not securely fixed, allowing displacement and subsequent damage during use or transport.

Innovation Solution

A guide with projections is placed between the cover bottom and the light guide plate to stabilize it, featuring a first support contacting the lower part of the light guide plate and a second support with projections extending towards its side surface, preventing displacement and damage during expansion and contraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the light guide plate is spaced from the cover bottom to allow for expansion and contraction, then the light guide plate can expand and contract freely, but the light guide plate becomes unstable and susceptible to displacement and damage

Engineering Contradiction:

Improveexpansion and contraction capabilityVSAvoidstability of light guide plate

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The guide structure provides localized support at specific positions (first support at lower part, second support at side surface) rather than uniform support across the entire light guide plate. This allows the light guide plate to expand and contract freely in areas without support while maintaining stability at supported locations, resolving the contradiction between freedom of expansion and overall stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The support structure is divided into multiple discrete support points (first support and second support) rather than continuous support. This segmentation allows different regions of the light guide plate to have different degrees of freedom - supported regions maintain position while unsupported regions can expand and contract, simultaneously achieving both stability and adaptability.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the light guide plate is securely fixed to prevent displacement, then stability is improved, but expansion and contraction are restricted causing deformation

Engineering Contradiction:

Improvestability of light guide plateVSAvoidexpansion and contraction capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The guide provides selective local support at the lower part and side surface of the light guide plate, ensuring stability at these critical positions while leaving other areas free to expand and contract. This localized approach prevents the light guide plate from deforming during thermal cycles while maintaining overall structural stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

By using discrete support points rather than continuous fixation, the guide allows the light guide plate to maintain stability at supported locations while freely expanding and contracting in unsupported regions, resolving the contradiction between secure fixing and thermal adaptability.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If the light guide plate is left loose to allow displacement, then expansion and contraction are accommodated, but scratches and damage occur on the surface

Engineering Contradiction:

Improveexpansion and contraction capabilityVSAvoidsurface damage and scratches

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The guide structure provides localized support at the lower part and side surface of the light guide plate, preventing displacement and surface damage at these critical positions while allowing the rest of the plate to expand and contract freely. This resolves the contradiction between accommodating thermal expansion and preventing surface damage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The segmented support structure with discrete support points allows the light guide plate to expand and contract in unsupported regions without causing displacement-induced damage, while maintaining surface integrity at supported locations. This segmentation approach simultaneously achieves thermal adaptability and damage prevention.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9696483B2Backlight unit and display device including the same

Publication Date: 2017.07.04 LG DISPLAY CO LTD

AI summary

Disclosed are a backlight unit and a liquid crystal display device including the same to stably fix a light guide plate. The backlight unit includes a guide disposed between a cover bottom, on which a light guide plate is mounted, and the light guide plate, the guide having a plurality of projections in an area in which the guide contacts the light guide plate.