Backlight Unit Rubber Corner Support for LCD Luminance Stability

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Solution Overview

Problem

Existing liquid crystal display (LCD) devices using edge light methods face issues with uneven luminance due to temperature-induced deformation of plastic frames with elastic press-supporting parts, leading to instability and difficulty in assembly, especially in varying environmental temperatures.

Innovation Solution

A backlight unit design featuring a quadrilateral light guide plate pressed by rubber members with cylindrical parts, which absorb and recover from temperature changes, ensuring constant support to light-emitting diodes and facilitating easy assembly by using an inner and outer frame structure with rubber members placed at corners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plastic frame with elastic press-supporting parts is used to press the light guide plate, then the light guide plate can be supported, but the press-supporting part deforms under temperature changes causing uneven luminance

Engineering Contradiction:

Improvesupport stabilityVSAvoidtemperature-induced deformation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter from plastic to rubber, which has different thermal expansion characteristics. Rubber's elastic modulus and thermal properties allow it to maintain stable pressing force across temperature variations, preventing the deformation that occurs with plastic materials.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses rubber as a composite material that combines elasticity with temperature stability. The rubber material provides both the necessary pressing force and resistance to thermal deformation, creating a support mechanism that maintains consistent performance across environmental temperature ranges.

Inventive Principle:

Principle #40Composite materials

2Reliability

If plastic springs are set on each side of the frame to press the light guide plate, then stable supporting condition is achieved, but assembly becomes difficult and position is unsettled

Engineering Contradiction:

Improvesupport stabilityVSAvoidassembly difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies rubber members only at specific corner positions rather than distributing them across all sides. This localized placement provides sufficient support stability while significantly simplifying the assembly process, as only four corner positions need to be addressed rather than multiple positions along edges.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses asymmetric placement of rubber members at corners rather than symmetric distribution along edges. This asymmetric configuration simplifies assembly by requiring fewer components and allows for easier positioning of the light guide plate during manufacturing.

Inventive Principle:

Principle #4Asymmetry

3Productivity

If the light guide plate is placed near the light part, then light induction efficiency is improved, but positioning becomes difficult without additional support structures

Engineering Contradiction:

Improvelight induction efficiencyVSAvoidpositioning difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent merges the support function with the positioning function by using the same rubber members to both press the light guide plate against the light part and maintain its position. This eliminates the need for separate support structures and allows the light guide plate to be placed close to the light source for optimal efficiency.

Inventive Principle:

Principle #5Merging (Combining)

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 provides stable support to the light guide plate across temperature ranges, preventing uneven luminance and simplifying assembly, resulting in improved image quality and reliability of LCD devices.

Implementation Method 1

rubber members which press the light guide plate to the light-emitting diodes; wherein a side of the inner frame is opposite to the light-emitting diodes, and two corners are formed edges of the side

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the rubber member comprises a cylindrical part; and wherein the cylindrical part is projected inside of the inner frame

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8154682B2Backlight unit and liquid crystal display device having the same

Publication Date: 2012.04.10 MAGNOLIA WHITE CORP

AI summary

A backlight unit comprising: a quadrilateral light guide plate 4; and a substrate 3 comprises a plurality of light-emitting diodes 2; and an inner frame 8 which surround the light guide plate 4; and an outer frame 7 which surround the inner frame 8 and the substrate 3; a plurality of rubber members 9; wherein a side of the inner frame 8 is opposite to the light-emitting diodes 2, and two corners are formed edges of the side; and the rubber member 9 is placed the each corners; and wherein the rubber member 9 comprises a cylindrical part; and wherein the cylindrical part is projected inside of the inner frame 8.