LED Wavelength Conversion via Selective Protection Layer Removal

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Solution Overview

Problem

Manufacturing white light LEDs on a single wafer is challenging due to varying emission wavelengths and optical powers, making it difficult to achieve desired CIE coordinates, and existing methods struggle to efficiently form light-emitting devices with consistent opto-electrical properties.

Innovation Solution

A method involving the formation of light-emitting units with a protection layer, followed by the removal of specific parts to expose electrodes, and the application of a wavelength conversion layer to achieve uniform emission characteristics, allowing for the creation of light-emitting devices with desired color temperature regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple light-emitting units are manufactured on a single wafer, then productivity is improved, but manufacturing precision deteriorates due to varying emission wavelengths and optical powers making it difficult to obtain desired CIE coordinates for each LED

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidCIE coordinate consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent divides the single wafer into multiple light-emitting units, each with its own protection layer that can be independently removed. This segmentation allows each LED to be individually processed and adjusted while maintaining the efficiency of wafer-level manufacturing. The protection layer acts as a temporary mask that enables selective access to each LED's light-emitting surface for precise wavelength conversion layer deposition.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different wavelength conversion layers to different light-emitting units based on their specific emission characteristics. By removing protection layers selectively and depositing customized wavelength conversion layers on individual LEDs or groups of LEDs with similar characteristics, the system achieves local optimization of color coordinates while maintaining overall manufacturing efficiency.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If protection layers are formed on all light-emitting units, then ease of manufacture is improved through standardized wafer-level processing, but device complexity increases due to the additional steps of selective removal and re-application of protection layers

Engineering Contradiction:

Improvewafer-level processingVSAvoidprocess steps

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The protection layer is formed in advance on all light-emitting units before wafer-level processing. This preliminary action enables standardized initial processing while allowing subsequent selective removal and re-application steps to customize each LED's wavelength conversion characteristics without requiring complex real-time adjustments during manufacturing.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If wavelength conversion layers are applied to all light-emitting units uniformly, then manufacturing precision is improved, but adaptability deteriorates because individual LED characteristics cannot be optimized

Engineering Contradiction:

Improvecolor coordinate controlVSAvoidindividual LED optimization

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent enables local quality optimization by allowing different wavelength conversion layers to be applied to different light-emitting units or groups based on their specific emission wavelengths and optical powers. The selective removal and re-application of protection layers facilitates this localized customization while maintaining overall manufacturing efficiency.

Inventive Principle:

Principle #3Local quality

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 method enables the production of light-emitting devices with consistent opto-electrical properties and desired CIE coordinates, facilitating the creation of white light with precise color temperature regions by mixing light from different wavelength conversion layers.

Implementation Method 1

forming a wavelength conversion layer on the first part and the light-emitting stack not covered by the second part

Methodology Applied

Scientific EffectWavelength conversion: Fluorescence

Data Source

PatentUS9543464B2Method of making a light emitting device and a light emitting device made thereof

Publication Date: 2017.01.10 ENNOSTAR CORP

AI summary

The method includes preparing a plurality of light-emitting units, one of the plurality of light-emitting units comprising an electrode, a light-emitting stack, and a protection layer with a first part covering the electrode and a second part which comprises a portion surrounding the electrode and covers the light-emitting stack; removing the portion without removing the first part; forming a wavelength conversion layer on the first part and the light-emitting stack not covered by the second part; and removing the first part to substantially expose the electrode.