Side Prism Light Guide for Illumination Uniformity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional illumination devices suffer from light loss due to escape from the light guide through side surfaces before reaching the exit, leading to decreased light-emitting efficiency and uneven luminance in display devices.

Innovation Solution

The illumination device employs a light guide configuration with strategically positioned prisms on the side surfaces, optimizing the incident and prism angles to confine light within the guide, ensuring it is emitted only through the main surface, thereby reducing escape and enhancing uniformity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If light is emitted from the side surface of the light guide, then the light guide can be simpler in structure, but light escapes from the side surface resulting in decreased light-emitting efficiency

Engineering Contradiction:

Improvelight guide structureVSAvoidlight-emitting efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of light escaping from side surfaces into a beneficial effect by strategically positioning prisms on these surfaces. The prisms refract the escaping light back into the light guide, transforming what was previously a loss mechanism into a light-recycling mechanism that improves overall light-emitting efficiency

Inventive Principle:

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

Solution Approach 2:

The patent applies prisms only at specific locations on the side surfaces of the light guide rather than uniformly across all surfaces. This localized application of optical elements allows selective control of light paths where needed while maintaining simplicity in other areas, resolving the contradiction between structural complexity and light efficiency

Inventive Principle:

Principle #3Local quality

2Device complexity

If light escapes from the side surface of the light guide, then the light guide configuration can be simpler, but uneven luminance occurs in the display device

Engineering Contradiction:

Improvelight guide configurationVSAvoidluminance uniformity

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The prisms on side surfaces convert escaped light back into the light guide, creating additional light paths that contribute to uniform luminance distribution across the display device, thereby transforming a harmful escape effect into a beneficial uniformity-enhancing mechanism

Inventive Principle:

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

Solution Approach 2:

The patent introduces a new dimension of light control by adding prismatic surfaces at angled orientations on the side surfaces. This creates additional light redirection pathways in three-dimensional space, enabling more uniform luminance distribution across the display area

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If light escapes from the side surface of the light guide, then fewer optical components are needed, but chromaticity deviations increase

Engineering Contradiction:

Improveoptical componentsVSAvoidchromaticity uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The prisms convert chromaticity-degrading light escape into a beneficial effect by refracting escaped light back into the light guide. This light recycling process maintains chromaticity consistency because the light follows controlled optical paths through the prisms, preventing the chromaticity deviations that would occur with uncontrolled escape

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 significantly improves light-emitting efficiency by minimizing escape light, resulting in more uniform luminance distribution across the display panel, reducing chromaticity deviations and enhancing overall display quality.

Implementation Method 1

a first layer including a first prism provided on the second side surface... the first prism protrudes from the second main surface toward the opposite side to the first main surface and has a cross-sectional shape of a triangle

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

The light from the light source enters the light guide from a side surface of the light guide, propagates inside the light guide, and exits from an exit surface corresponding to one main surface of the light guide

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS11796730B2Illumination device including second prism and bent portion of reflective sheet and display device including the same

Publication Date: 2023.10.24 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, an illumination device includes a first light guide including a first main surface, a second main surface, a first side surface and a second side surface, a first light source and a first layer including a first prism provided on the second side surface. The first prism protrudes from the second main surface toward the opposite side to the first main surface and has a cross-sectional shape of a triangle with a first slope and a second slope. The incident angle of light emitted from the first light source and entering the first light guide from the second side surface, the angle between the first slope and the first direction, and the angle between the first slope and the second slope are set to values that satisfy the predetermined conditions, respectively.