Backlight Partition Wall Openings for Luminance Uniformity

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Solution Overview

Problem

Conventional liquid crystal display devices experience luminance unevenness due to partition walls blocking illumination light between adjacent regions, and the use of lenses complicates thickness reduction.

Innovation Solution

A backlight device with a matrix arrangement of light sources, a reflective sheet with partition walls surrounding each light source, and a luminance uniformity plate supported by members that shield and position openings in the partition walls to minimize light interference and maintain even luminance distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If partition walls are arranged to surround each light source, then light interference between adjacent regions is prevented, but luminance unevenness occurs in neighboring areas above partition walls

Engineering Contradiction:
Improvelight interferenceVSAvoidluminance unevenness
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent applies local quality by providing opening portions in specific locations of the partition walls (non-corner areas) rather than uniformly across all partition walls. This localized modification allows light to pass through strategic positions to illuminate neighboring areas above partition walls, correcting luminance unevenness while maintaining the partitioning function for light interference prevention.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If lenses are arranged on LEDs to increase luminance ratio, then dynamic range is improved, but device thickness increases

Engineering Contradiction:
Improveluminance ratioVSAvoiddevice thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent extracts and removes the lens component from the LED assembly. Instead of using lenses to increase luminance ratio, the invention achieves the desired luminance distribution through the opening portions in the partition walls and the reflective sheet configuration, thereby eliminating the thickness contribution of lenses while maintaining improved dynamic range.

Inventive Principle:
Principle #2Taking out (Extraction)

3Illumination intensity

If support members are placed in opening portions of partition walls, then luminance uniformity is improved, but light leakage may occur

Engineering Contradiction:
Improveluminance uniformityVSAvoidlight leakage
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a shield portion as an intermediary element within the support members. This shield portion is positioned to block light leakage paths created by the opening portions in the partition walls, while the support members themselves maintain their function of supporting the reflective sheet and improving luminance uniformity. The shield acts as a mediator that resolves the conflict between luminance uniformity improvement and light leakage prevention.

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 configuration reduces luminance unevenness and achieves a thinner display device by minimizing light leakage and maintaining consistent luminance distribution while eliminating the need for lenses.

Implementation Method 1

a reflective sheet (23) having partition walls (231) arranged to surround each of the plurality of light sources (21) in four directions and reflecting light emitted from the plurality of light sources (21)

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a luminance uniformity plate (24) located above the reflective sheet (23) and uniforming luminance of the light emitted from the plurality of light sources (21) and light reflected by the reflective sheet (23)

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP3318792B1Backlight device and liquid-crystal display device
Publication Date: 2020.02.26 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3318792B1 patent drawingFigure 1
  • EP3318792B1 patent drawingFigure 2
  • EP3318792B1 patent drawingFigure 3~4

AI summary

A backlight device includes a plurality of light sources arranged in a shape of a matrix, a reflective sheet having partition walls arranged to surround each of the plurality of light sources in four directions and reflecting light emitted from the plurality of light sources, a luminance uniformity plate located above the reflective sheet and uniforming luminance of the light emitted from the plurality of light sources and light reflected by the reflective sheet, and a support member supporting the luminance uniformity plate. The reflective sheet has an opening portion in a portion, of at least one partition wall of the partition walls arranged in the four directions, which is other than four corners, and the support member has a shield portion disposed in the opening portion and shielding the opening portion.