Optical Path Conversion Unit for Display Light Guide Plate

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Solution Overview

Problem

Display devices using LED backlight units face challenges in reducing light loss and achieving color uniformity, which affect brightness and overall display performance.

Innovation Solution

The implementation of an optical path conversion unit with inclined planes on a light guide plate, strategically positioned to redirect light paths, reduces external light escape and enhances brightness uniformity by total-reflection of light within the guide plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light is emitted from the light source toward the light guide plate, then the light guide plate can provide illumination, but light escapes through the lateral sides and top of the light guide plate causing light loss and reduced brightness uniformity

Engineering Contradiction:

ImprovebrightnessVSAvoidlight loss

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent converts the harmful light escape through lateral sides into a beneficial effect by using inclined planes to redirect this escaped light back onto the light guide plate, where it undergoes total internal reflection and is redirected to the top surface, thus converting light loss into useful illumination

Inventive Principle:

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

Solution Approach 2:

The patent introduces inclined planes that operate in a three-dimensional space, redirecting light paths from horizontal escape directions into vertical reflection paths, effectively using dimensional transformation to control light propagation and prevent light loss

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If light is emitted from the light source, then illumination is provided, but brightness uniformity is poor due to light escaping at large angles

Engineering Contradiction:

Improvebrightness uniformityVSAvoidbrightness uniformity

Core Design Contradiction:

Illumination intensityVSEase of operation

Solution Approach 1:

The patent converts the harmful effect of light escaping at large angles (which causes brightness non-uniformity) into a beneficial effect by using inclined planes to capture and redirect this light back onto the light guide plate, ensuring uniform distribution across the top surface

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 solution improves brightness and brightness uniformity by minimizing light loss through the lateral sides and top of the light guide plate, resulting in enhanced display performance.

Implementation Method 1

the light whose path is converted by the optical conversion member is total-reflected at the light guide plate

Methodology Applied

Scientific EffectTotal reflection: Total Internal Reflection

Data Source

PatentUS9110203B2Display device with light guide plate and optical path conversion unit

Publication Date: 2015.08.18 LG INNOTEK CO LTD

AI summary

Provided is a display device. The display device includes a light guide plate; a light source disposed at a lateral side of the light guide plate; and an optical path conversion unit converting a path of the light emitted from the light source. A first area corresponding to a light emitting plane of the light guide plate and a second area adjacent to the first area are defined. The optical path conversion unit is disposed in the second area.