Optical Member Light Incident Part Brightness Uniformity

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Solution Overview

Problem

Conventional backlight units in LCDs face challenges in achieving balanced brightness and color reproduction due to the concentration of light, which can lead to degradation of wavelength conversion particles and heat-related issues, affecting reliability and color accuracy.

Innovation Solution

The optical member features a light incident part with a thickness ranging from 100µm to 1000µm, which diffuses light output from the source, preventing concentration and allowing for effective heat dissipation, thereby enhancing brightness uniformity and color reproduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the light source is positioned to supply light over the whole area of the liquid crystal display panel, then high brightness can be achieved, but the thickness must be larger to ensure brightness uniformity

Engineering Contradiction:
ImprovebrightnessVSAvoidthickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent introduces a light incident part with greater thickness than the light exit part, creating an asymmetric thickness distribution. This dimensional change in the light guide plate structure allows light to be diffused effectively while maintaining overall thinness, resolving the contradiction between achieving high brightness and maintaining thin profile.

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

Solution Approach 2:

The patent applies different thickness characteristics to different regions of the light guide plate: the light incident part has greater thickness (100-1000µm) to diffuse light effectively, while the light exit part has smaller thickness to maintain overall thinness. This local differentiation resolves the contradiction between brightness uniformity and thinness.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If the thickness of the light incident part is increased to diffuse light, then brightness uniformity is improved, but the device complexity increases

Engineering Contradiction:
Improvebrightness uniformityVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent combines the light diffusion function and the structural support function into a single light guide plate component. The light incident part with greater thickness performs both light diffusion and structural roles, eliminating the need for separate diffusion elements and reducing overall device complexity while improving brightness uniformity.

Inventive Principle:
Principle #5Merging (Combining)

3Length of stationary object

If light is concentrated in specific regions, then the light guide plate can be thinner, but the wavelength conversion particles degrade due to heat

Engineering Contradiction:
ImprovethicknessVSAvoidparticle degradation
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent uses the thickness dimension of the light incident part (100-1000µm) to provide a thermal management solution. This increased thickness in the incident region creates a thermal buffer that prevents heat concentration, protecting wavelength conversion particles from degradation while maintaining thin overall device profile.

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

Solution Approach 2:

The light incident part with greater thickness acts as an intermediary between the light source and the wavelength conversion particles. It diffuses light and dissipates heat before light reaches the particles, preventing thermal damage while enabling the use of thinner overall structure.

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

This design improves brightness, brightness uniformity, and reliability by ensuring that wavelength conversion particles are not degraded, allowing for better color reproduction and extended usage without heat-induced damage.

Implementation Method 1

after the light output from the light source has been sufficiently diffused through the light incident part

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

a quantum dot bar having a plurality of quantum dots, which can convert blue light into red light or green light

Methodology Applied
Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentEP2734875B1Optical member and display device having the same
Publication Date: 2022.12.28 LG INNOTEK CO LTD
  • EP2734875B1 patent drawingFigure 1
  • EP2734875B1 patent drawingFigure 2~3
  • EP2734875B1 patent drawingFigure 4~6

AI summary

Disclosed are an optical member and a display device having the same. The optical member includes a receiving part, a host in the receiving part, and a plurality of wavelength conversion particles in the host. The receiving part includes a light incident part making contact with the host, and a light exit part in which the host is sandwiched between the light incident part and the light exit part.