Curved Reflective Layer for Thin Light-Emitting Structures

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Solution Overview

Problem

Current light-emitting devices face challenges in optimizing light extraction efficiency and reducing thickness while maintaining high reflectivity, particularly in applications like mobile phones and liquid crystal displays, where the existing reflective layers do not effectively direct light emission.

Innovation Solution

The proposed light-emitting device incorporates a second reflective layer with a curved inner surface that covers only specific sides of a light-transmitting body, enhancing light reflection and extraction efficiency by adjusting the thickness and material composition to achieve high reflectivity across various wavelengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a reflective layer is added to improve light extraction efficiency, then light output increases, but device thickness increases

Engineering Contradiction:
Improvelight outputVSAvoiddevice thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The reflective layer features a curved inner surface that reflects light from the light-emitting element. This curved geometry enables efficient light extraction and redirection toward the display surface, improving luminous flux without requiring additional thickness. The curvature optimizes optical path control within the constrained thickness of the light-transmitting body.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The reflective layer is selectively positioned only at specific regions where light extraction enhancement is needed, rather than uniformly covering the entire light-transmitting body. This localized approach optimizes light output while minimizing the impact on device thickness and maintaining compact form factor.

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If the light-transmitting body is made thinner to reduce device thickness, then compact form factor is achieved, but light extraction efficiency decreases

Engineering Contradiction:
Improvedevice thicknessVSAvoidlight extraction efficiency
Core Design Contradiction:
Length of stationary objectVSIllumination intensity

Solution Approach 1:

The curved inner surface of the reflective layer compensates for the reduced thickness of the light-transmitting body by optimizing light reflection angles. This curvature ensures that light from the LED is effectively redirected toward the display surface, maintaining high extraction efficiency even in thin-profile configurations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces optical dimensionality through the curved reflective surface, transforming the light extraction problem from a thickness-dependent constraint to a geometry-optimized solution. The curvature adds optical path control in the angular dimension, enabling efficient light extraction without increasing physical thickness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If a reflective layer covers all sides of the light-transmitting body, then light extraction is maximized, but device complexity increases

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidstructural complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflective layer is applied selectively to specific sides or regions of the light-transmitting body where light extraction enhancement provides the greatest benefit. This localized coverage reduces manufacturing complexity and material usage while maintaining effective light output improvement.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Rather than applying the reflective layer to all surfaces, the patent uses partial coverage focused on critical light extraction zones. This partial action approach achieves sufficient light extraction enhancement without the excessive complexity of complete surface coverage.

Inventive Principle:
Principle #16Partial or excessive action

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 increases light output and luminous flux while maintaining a compact form factor, suitable for thin-profile applications like mobile devices and liquid crystal displays, with improved light-emitting angles and intensity distribution.

Implementation Method 1

a reflective layer covering two sides of the light-transmitting body

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3188263B1Light-emitting device
Publication Date: 2024.04.03 EPISTAR CORP
  • EP3188263B1 patent drawingFigure 1A
  • EP3188263B1 patent drawingFigure 1B~1C
  • EP3188263B1 patent drawingFigure 1D

AI summary

A light-emitting device includes a light-emitting structure with a side surface, and a reflective layer covering the side surface. The light-emitting structure has a first light-emitting angle and a second light-emitting angle. The difference between the first light-emitting angle and the second light-emitting angle is larger than 15°.