Micro LED Light Trapping Structure for Color Conversion Efficiency

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Solution Overview

Problem

Micro LED displays face inefficiencies in power consumption and color conversion, particularly in converting blue light to red and green light, due to the use of thick quantum dot films which result in low power conversion efficiency and increased leakage, leading to reduced battery life and picture clarity in mobile devices.

Innovation Solution

A light trapping structure is implemented using two mirrors, a wavelength-selective mirror and a broadband mirror, to sandwich a micro LED and a quantum dot film, allowing incident blue light to pass through the color conversion layer multiple times, improving conversion efficiency and reducing leakage by reflecting blue light back into the film, while preventing ambient light exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If thick quantum dot films are used for color conversion, then the film can convert blue light to red and green light, but the power conversion efficiency is low and blue light leakage increases

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidblue light leakage

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-coating the quantum dot film with a wavelength-selective mirror layer before depositing the quantum dots. This pre-established optical structure guides the blue light through the quantum dot film multiple times, ensuring efficient absorption and conversion before the light can leak out, thereby reducing blue light leakage while improving power conversion efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements continuity of useful action by creating an optical cavity structure with mirrors on both sides of the quantum dot film. This structure causes the blue light to bounce back and forth through the quantum dot film multiple times, continuously converting blue light to red and green light, thereby maximizing the utilization of incident light and improving overall conversion efficiency while minimizing leakage

Inventive Principle:

Principle #20Continuity of useful action

2Quantity of substance

If thick quantum dot films are used, then color conversion is achieved, but battery life is reduced due to increased power consumption

Engineering Contradiction:

Improvequantum dot film thicknessVSAvoidpower consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness of the quantum dot film to a specific range (50-200 nm) and adjusting the optical properties of the mirror layers. This optimized parameter combination achieves effective color conversion with minimal film thickness, thereby reducing power consumption while maintaining display quality, which directly addresses the battery life issue

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If thick quantum dot films are used, then the film can convert wavelengths, but manufacturing precision and display clarity are reduced

Engineering Contradiction:

Improvequantum dot film thicknessVSAvoiddisplay clarity

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent employs thin film technology by using ultra-thin quantum dot films (50-200 nm) coated on flexible substrate structures with integrated mirror layers. This thin film approach achieves precise wavelength conversion while maintaining excellent manufacturing precision and display clarity, eliminating the problems associated with thick films such as poor resolution and manufacturing difficulty

Inventive Principle:

Principle #30Flexible shells and thin films

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 enhances external quantum efficiency, reduces blue light leakage, and achieves a thinner quantum dot film, resulting in lower power consumption and improved display clarity with reduced manufacturing costs and increased efficiency in color conversion.

Implementation Method 1

a quantum dot film to convert the first wavelength light to the second wavelength light

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS11430921B2Micro LED apparatus including color conversion structures and methods of manufacturing the same

Publication Date: 2022.08.30 INTEL CORP

AI summary

Apparatus, systems, methods, and articles of manufacture to generate, trap, and convert light using a micro light emitting diode (LED) or similar device are disclosed. An example apparatus includes a first mirror to reflect a first wavelength light and a second wavelength light. The example apparatus includes a micro LED on the first mirror, the micro LED to generate the first wavelength light. The example apparatus includes a quantum dot film on the micro LED, the quantum dot film to convert the first wavelength light to the second wavelength light. The example apparatus includes a second mirror on the quantum dot film, the second mirror to reflect the first wavelength light and transmit the second wavelength light.