Light Unit Protrusions and Reflective Member for LCD Backlight Leakage Control

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Solution Overview

Problem

Conventional backlight assemblies for liquid crystal displays (LCDs) face challenges in optimizing light distribution and reducing light leakage, leading to variations in display quality due to the positioning of light sources relative to the display surface.

Innovation Solution

The proposed light unit incorporates a light guide plate and a reflective member under the light guide plate, with protrusions on the light emitting devices and the light guide plate to direct light efficiently and minimize leakage, enhancing brightness by reflecting stray light and improving light utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a lamp is mounted at the side of the display surface (edge-type backlight assembly), then the light source can be positioned to illuminate the display panel, but light leakage occurs and light distribution uniformity deteriorates

Engineering Contradiction:
ImprovebrightnessVSAvoidlight leakage
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful reflected light by introducing a light absorbing member that selectively absorbs light in specific directions. The light absorbing member is positioned to intercept light reflected from the light guide plate at angles that would cause leakage, removing this harmful effect while preserving useful light transmission to the display panel.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The light absorbing member acts as an intermediary element between the light guide plate and the surrounding environment. It mediates the light paths by absorbing stray light that would otherwise leak out, converting harmful reflected light into heat energy that is then dissipated, thus preventing light leakage without interfering with the primary light transmission function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional light sources are used without optimization, then the backlight assembly can be assembled, but light distribution uniformity and display quality vary

Engineering Contradiction:
ImproveassemblyVSAvoidlight distribution uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The light absorbing member is strategically positioned at specific locations where light leakage occurs, rather than uniformly distributing light-absorbing material throughout the entire assembly. This localized approach addresses light distribution non-uniformity precisely where needed, improving manufacturing precision without complicating the overall assembly process.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The light absorbing member is divided into multiple segments or sections, each positioned to address specific leakage zones. This segmentation allows for precise control over light absorption in different regions, enabling better light distribution uniformity while maintaining ease of assembly through modular placement.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If light is emitted without directional control, then the light source can operate simply, but light leakage increases and brightness efficiency decreases

Engineering Contradiction:
Improvelight direction controlVSAvoidlight utilization efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of reflected light (which would cause leakage) into a beneficial function. By positioning the light absorbing member to intercept these reflected rays, the previously wasted light energy is systematically managed and absorbed, preventing leakage while the heat generated is dissipated, thus improving overall light utilization efficiency without adding complex directional control mechanisms.

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

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 effectively reduces light leakage and enhances overall brightness by ensuring that emitted light is directed onto the display panel as surface light, improving the uniformity and quality of the displayed image.

Implementation Method 1

a reflective member under the light guide plate, with protrusions on the light emitting devices and the light guide plate to direct light efficiently and minimize leakage, enhancing brightness by reflecting stray light

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2381494B1light unit
Publication Date: 2019.08.21 LG INNOTEK CO LTD
  • EP2381494B1 patent drawingFigure 1~2
  • EP2381494B1 patent drawingFigure 3~4
  • EP2381494B1 patent drawingFigure 5~6

AI summary

Disclosed are a light emitting device and a light unit including the same. The light emitting device includes a body having a cavity with an open upper portion, a protrusion protruding from an upper portion of the body, a plurality of lead electrodes in the cavity, and a light emitting diode provided in the cavity and electrically connected to the lead electrodes.