Polarized LED with Segmented Optical Layers

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Solution Overview

Problem

Current LED technologies face inefficiencies in producing polarized light, with existing methods achieving only about 45% polarization efficiency, which is insufficient for many applications, and the manufacturing of polarized LEDs with exotic crystal orientations is complex and inefficient.

Innovation Solution

A light emitting device comprising a LED die with a light polarizing layer on one surface, a light blocking layer on the side facets, and a light reflecting layer on the other surface, along with an optional recycling layer to enhance polarization efficiency, using a wire-grid grating polarizing layer and a wavelength conversion layer to increase polarized light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional light sources are used, then the light emission is simple and manufacturing is easy, but the polarization efficiency is low (about 45%)

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpolarization efficiency
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The LED die surface is segmented into different functional zones: a light polarizing layer on the first surface for polarization, a light blocking layer on the side facets to prevent non-polarized light escape, and a light reflecting layer on the second surface to redirect light. This segmentation allows each zone to perform its specific function optimally, achieving high polarization efficiency while maintaining manufacturing simplicity through standardized layer deposition processes.

Inventive Principle:
Principle #1Segmentation

2Use of energy by moving object

If exotic crystal orientation directions are used in LED fabrication, then polarized light emission is achieved, but the manufacturing complexity increases and light output efficiency decreases

Engineering Contradiction:
Improvepolarized light emission efficiencyVSAvoidfabrication complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

Instead of modifying the bulk crystal orientation of the LED (which would increase fabrication complexity), the patent extracts the polarization function to a separate light polarizing layer deposited on the LED surface. This layer selectively transmits polarized light while blocking non-polarized light, achieving polarized light emission without altering the LED's fundamental structure or fabrication process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The light polarizing layer serves multiple functions: it polarizes light emitted from the LED, acts as a protective coating, and can be integrated with the LED's existing surface structure. This multi-functionality achieves polarized light emission without requiring separate complex polarization components, maintaining manufacturing simplicity while improving polarization efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If a light polarizing layer is added to the LED, then polarization contrast is improved, but the device structure becomes more complex

Engineering Contradiction:
Improvepolarization contrastVSAvoidlayer structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple layers (light polarizing layer, light blocking layer, light reflecting layer) into an integrated structure that works as a unified system. These layers are deposited in sequence during a single manufacturing process, forming a compact multi-functional coating on the LED die. This merging approach achieves high polarization contrast while minimizing the increase in device complexity through standardized multi-layer deposition techniques.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution achieves high polarization contrast and efficiency, allowing for increased polarized light emission, addressing the inefficiencies of existing methods and enhancing visual perception by reducing glare and improving color saturation.

Implementation Method 1

The light polarizing layer transmits a first portion of light emitted from the LED, and reflects a second portion of the light emitted from the LED

Methodology Applied
Scientific EffectLight polarization: Polarisation

Implementation Method 2

The reflected light is incident on the LED, and reflected by the LED

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

using a wire-grid grating polarizing layer and a wavelength conversion layer to increase polarized light emission

Methodology Applied
Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentEP2206166B1Polarized light emitting device
Publication Date: 2019.04.17 LUMILEDS HLDG BV
  • EP2206166B1 patent drawingFigure 1~2
  • EP2206166B1 patent drawingFigure 3~4
  • EP2206166B1 patent drawingFigure 5~7

AI summary

The present invention relates to a light emitting device, comprising: a LED die (10) having a first surface (12), a second surface (14) and at least one side facet (16) connecting the first and the second surface (12, 14). Further, the LED die comprises a light polarizing layer (20), a light blocking layer (30), and a light reflecting layer (40). The light polarizing layer (20) is arranged on the first surface (12), the light blocking layer (30) is arranged on the at least one side facet (16), and the light reflecting layer (40) is arranged on the second surface (14) of the LED die.