Backlight Reflecting Sheet with Radial Dots for Uniform Illumination

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Solution Overview

Problem

Current display devices face challenges in optimizing light reflectance, leading to non-uniform brightness and luminance due to the inefficiencies in light distribution from the backlight unit, particularly with the use of LEDs and reflective sheets.

Innovation Solution

The implementation of a reflecting sheet with a three-dimensional shape and strategically placed dots and non-dot areas, coupled with a COB light source, optimizes light reflection and distribution across the display panel, ensuring uniform light emission and reducing non-uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a conventional reflective sheet is used in the backlight unit, then the light distribution is simple, but the light reflectance is insufficient and non-uniform brightness occurs

Engineering Contradiction:
Improvelight reflectanceVSAvoidreflective sheet structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflective sheet is divided into multiple regions with different reflective properties. First reflective regions have a first reflective property while second reflective regions have a second reflective property different from the first. This local differentiation allows optimization of light reflection in different areas of the backlight unit, addressing non-uniform brightness by ensuring each region reflects light appropriately for its position and function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The reflective sheet is segmented into multiple first reflective regions and second reflective regions distributed across its surface. This segmentation enables independent optimization of light reflection characteristics in different zones, allowing the design to achieve uniform overall light distribution while maintaining manageable structural complexity through modular region definition.

Inventive Principle:
Principle #1Segmentation

2Use of energy by moving object

If LEDs are used as light sources with lenses, then energy efficiency is improved, but light distribution uniformity deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoidlight distribution uniformity
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

Different regions of the reflective sheet are assigned different reflective properties to compensate for the directional light emission characteristics of LEDs. Areas receiving light from specific LED positions receive reflective regions with adjusted reflectivity or orientation characteristics, ensuring uniform overall light distribution across the display panel while maintaining LED energy efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The differentiated reflective sheet acts as an intermediary between the LED light sources and the display panel. By strategically positioning reflective regions with different properties, the sheet mediates the light distribution, transforming the non-uniform LED emission pattern into uniform illumination across the panel surface.

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 enhances light reflectance and distribution, resulting in improved uniformity of brightness and luminance across the display device, providing a more consistent viewing experience.

Implementation Method 1

a reflective sheet with a three-dimensional shape and including a plurality of dots and non-dot areas

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3859442B1Display device including backlight unit
Publication Date: 2024.12.18 LG ELECTRONICS INC
  • EP3859442B1 patent drawingFigure 1
  • EP3859442B1 patent drawingFigure 2
  • EP3859442B1 patent drawingFigure 3

AI summary

A display device (100) is discloses which comprises a display panel (110), a frame (130) at the rear of the display panel (110), the frame (130) including a bottom (130a) and a sidewall (130b) extending from the bottom (130a), a substrate (122) on the frame (130), a light source (203) mounted on the substrate (122), a lens (300, 124b) mounted on the light source (203), wherein the lens (300, 124b) includes an upper surface (S1), a lower surface (S2), and a side surface (S3) connected with the upper surface (S1) and the lower surface (S2), a ring-shaped reflecting layer (126d) between the substrate (122) and the lens (300, 124b), and a plurality of dots (DT) formed on the top surface of the ring-shaped reflecting layer (126d), wherein the lower surface (S2) of the lens (300, 124b) includes a groove in which the light source (203) is inserted, and wherein the plurality of dots (DT) is disposed in a radial direction of the lens (300,124b) from the light source (203) and in an area under the lens (300,124b) between the side surface (S3) and the groove.