Elastic Guides Stabilize LCD Light Guide Plate

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Solution Overview

Problem

Existing liquid crystal display (LCD) devices face issues with light leakage and decreased image quality due to the movement of the light guide plate, which affects brightness and optical properties, especially in thin-profile and narrow-bezel designs where forming a stopper is challenging.

Innovation Solution

The use of elastic guides, such as silicone or polyurethane, to support the light guide plate and prevent movement, eliminating the need for guide grooves and maintaining an optical gap, thereby preventing light leakage and ensuring stable image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a stopper is formed in the guide panel to prevent light guide plate movement, then light leakage is blocked, but the device complexity increases and manufacturing becomes more difficult

Engineering Contradiction:
Improvelight leakageVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention extracts the light guide plate positioning function from the guide panel structure. Instead of forming a stopper in the guide panel, the light guide plate is positioned using its own edge structure that fits into a groove formed in the cover bottom, separating the positioning function from the guide panel and eliminating the need for additional stoppers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cover bottom groove serves multiple functions: it positions the light guide plate, prevents light leakage, and maintains the optical gap. This multi-functional design eliminates the need for separate stoppers and guide grooves, reducing device complexity while achieving the same light leakage prevention effect.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If guide grooves are formed in the cover bottom to position the light guide plate, then light leakage is prevented, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelight leakageVSAvoidgroove formation precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

Instead of forming complex guide grooves in the cover bottom, the invention inverts the approach by forming a simple positioning groove in the cover bottom and using the light guide plate's own edge structure for positioning. This inversion simplifies the groove geometry and reduces manufacturing precision requirements while maintaining effective light leakage prevention.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If the light guide plate is allowed to move freely, then device assembly is easier, but light leakage occurs and image quality decreases

Engineering Contradiction:
Improveassembly easeVSAvoidlight leakage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The light guide plate is designed with pre-formed edges that automatically position themselves when placed in the cover bottom groove. This preliminary structuring of the light guide plate enables self-positioning during assembly, maintaining ease of assembly while preventing light leakage without requiring complex positioning mechanisms.

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 effectively prevents light leakage and maintains image quality by stabilizing the light guide plate, enhancing brightness and image quality while allowing for a lightweight, slim, and narrow-bezel design.

Implementation Method 1

at least one of the guides includes an elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2749812B1Backlight unit for liquid crystal display device
Publication Date: 2019.02.20 LG DISPLAY CO LTD
  • EP2749812B1 patent drawingFigure 1
  • EP2749812B1 patent drawingFigure 2
  • EP2749812B1 patent drawingFigure 3A

AI summary

A backlight unit (120) for a liquid crystal display device includes a cover bottom (150) including a horizontal plane and sides perpendicular to the horizontal plane; guides (200) disposed at inner surfaces of the sides of the cover bottom and each including first, second and third portions, wherein the second portion protrudes from the first portion, and the third portion protrudes from the second portion and has elasticity; a reflection sheet (125)disposed on the first portions; a light guide plate (123) disposed over the reflection and on the second portions; an LED assembly (123) disposed at a first side of the light guide plate; and optical sheets (121) disposed over the light guide plate.