Backlight Unit Light Guide Plate Groove Projection

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Solution Overview

Problem

Conventional backlight units for LCD displays, particularly those using CCFLs, face issues with high power consumption, poor color reproduction, and environmental pollution due to mercury content, necessitating a more efficient and environmentally friendly alternative.

Innovation Solution

A backlight unit design featuring a light guide plate with a groove and a projection to guide light from a light source module, utilizing LED technology to reduce power consumption and enhance color reproduction, with the light guide plate and projection potentially made from materials like PMMA, PET, or COC, and featuring a reflector and optical member for improved light diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If CCFL is used as light source, then high brightness is achieved, but power consumption increases and color reproduction deteriorates

Engineering Contradiction:
ImprovebrightnessVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent changes the light source from CCFL to LED, which fundamentally alters the operating parameters including power consumption, lifespan, and color rendering capabilities. LEDs operate at lower power levels while providing comparable or superior brightness and color reproduction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adopts LED technology which, while having different cost characteristics, provides extended service life and reduced operational costs. The LED array with individual controllable elements allows for selective replacement or maintenance of specific components rather than entire systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Illumination intensity

If CCFL is used as light source, then high brightness is achieved, but color reproduction ratio deteriorates

Engineering Contradiction:
ImprovebrightnessVSAvoidcolor reproduction ratio
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent utilizes LED's superior color rendering properties by selecting LEDs with appropriate color temperatures and spectral characteristics. The ability to control individual LED colors in the array enables precise color mixing and reproduction exceeding 100% NTSC color gamut.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs multiple types of LEDs with different color characteristics (red, green, blue, white) arranged in an array. This composite approach allows for sophisticated color mixing and reproduction, achieving color accuracy and gamut that surpasses single-source illumination systems.

Inventive Principle:
Principle #40Composite materials

3Illumination intensity

If CCFL is used as light source, then illumination is provided, but environmental pollution is caused by mercury

Engineering Contradiction:
Improvelight outputVSAvoidmercury pollution
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mercury-containing CCFL with mercury-free LED technology. LEDs contain no hazardous materials like mercury, eliminating the environmental pollution problem while maintaining or improving illumination performance and reducing disposal concerns.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the environmental harm caused by mercury in CCFL into a benefit by adopting LED technology that not only eliminates pollution but also provides additional advantages such as lower power consumption, longer lifespan, and better color reproduction.

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

4Stability of the object's composition

If light source is arranged at edges for uniform diffusion, then good uniformity is achieved, but panel thickness increases

Engineering Contradiction:
Improvelight uniformityVSAvoidpanel thickness
Core Design Contradiction:
Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The patent transitions from edge-lit configuration to a bottom-lit configuration with a light guide plate. This dimensional change allows the light source to be positioned at the bottom rather than edges, enabling thinner overall panel construction while maintaining uniform light distribution through the light guide plate's optical properties.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a light guide plate as an intermediary component between the LED array and the display panel. This light guide plate diffuses and redistributes light uniformly across the panel surface, achieving good uniformity while allowing for reduced panel thickness compared to edge-lit designs.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 uniform brightness and reduced shadowing between light sources, achieving power savings and improved color reproduction beyond NTSC standards, while minimizing environmental impact by replacing CCFLs with LEDs.

Implementation Method 1

a projection from a side of the groove in the light guide plate toward the light source module for guiding a light from the light source module to the light guide plate

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

to have good uniformity of the light

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP2541136B1Backlight unit
Publication Date: 2019.05.08 LG INNOTEK CO LTD
  • EP2541136B1 patent drawingFigure 1~2
  • EP2541136B1 patent drawingFigure 3A~3B
  • EP2541136B1 patent drawingFigure 4A~4B

AI summary

Present inventions relate to a backlight unit and a display device with the same. The backlight unit includes a light guide plate having a groove, a light source module arranged in the groove, and a projection from a side of the groove in the light guide plate toward the light source module for guiding a light from the light source module to the light guide plate.