LED Wavelength Conversion Gradient for Color Rendition

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Solution Overview

Problem

Conventional light emitting devices using phosphors for wavelength conversion suffer from undesirable color distribution and degraded luminous efficiency due to random distribution of phosphors during the curing process of liquid resins.

Innovation Solution

A light emitting device with a wavelength conversion unit that includes two types of light wavelength converters with different emission spectrums, where the first converters are concentratively distributed in a lower region and the second converters in an upper region, forming a distribution gradient to enhance wavelength conversion efficiency and control color rendition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If phosphors are mixed with transparent liquid resin and applied to the LED chip periphery, then the device can be manufactured, but the phosphors are randomly distributed during curing, degrading color distribution yield and luminous efficiency

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidcolor distribution yield

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The wavelength conversion unit is divided into multiple regions (first mixture region adjacent to the luminous element and second mixture region above it), with different phosphor types concentrated in different regions. This segmentation allows controlled spatial distribution of phosphors, improving color distribution yield while maintaining manufacturability through the encapsulant structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the wavelength conversion unit are assigned different phosphor compositions - the first mixture region contains phosphors optimized for conversion near the luminous element, while the second mixture region contains different phosphors for upper region conversion. This local quality differentiation enables precise color rendering control in different spatial zones.

Inventive Principle:

Principle #3Local quality

2Device complexity

If phosphors are randomly distributed in the liquid resin, then the manufacturing process is simple, but luminous efficiency is degraded

Engineering Contradiction:

Improvestructure complexityVSAvoidluminous efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

Phosphors are pre-concentrated in specific regions within the encapsulant before the curing process completes. The first light wavelength converters are concentratively distributed in the first mixture region adjacent to the luminous element, and the second light wavelength converters are concentratively distributed in the second mixture region above it. This preliminary spatial arrangement ensures optimal wavelength conversion efficiency from the start, preventing energy loss.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If a single yellow phosphor is used with transparent liquid resin, then the manufacturing process is straightforward, but color rendition cannot be easily controlled

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcolor rendition control

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The wavelength conversion unit employs a composite structure containing multiple types of phosphors (first light wavelength converters and second light wavelength converters with different emission characteristics) distributed in different regions within the transparent encapsulant. This composite material approach enables precise control of color rendering index while maintaining ease of manufacture through the integrated encapsulant structure.

Inventive Principle:

Principle #40Composite materials

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 improves color distribution yield and luminous efficiency by optimizing the distribution of light wavelength converters, allowing for better control of the color rendering index and reducing light quantity loss.

Implementation Method 1

a wavelength conversion unit disposed on the support unit to cover the luminous element as an encapsulant containing first light wavelength converters emitting light of a first wavelength and second light wavelength converters emitting light of a second wavelength

Methodology Applied

Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentUS9347646B2Light emitting device providing controlled color rendition

Publication Date: 2016.05.24 SAMSUNG ELECTRONICS CO LTD

AI summary

A light emitting device for controlled color rendition includes a support unit; a luminous element mounted on the support unit; and a wavelength conversion unit formed on the support unit. The wavelength conversion unit covers the luminous element as an encapsulant containing first light wavelength converters emitting light of a first wavelength and second light wavelength converters emitting light of a second wavelength, where the first wavelength is larger than the second wavelength. The wavelength conversion unit includes a first mixture region adjacent to the luminous element and a second mixture region above the first mixture region. The first light wavelength converters are concentratively distributed in the first mixture region, and the second light wavelength converters are concentratively distributed in the second mixture region.