Light Emitting Device Luminescence Layer Integration

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Solution Overview

Problem

Nitride light-emitting devices face issues with non-uniform phosphor application and heat vulnerability in the packaging process, leading to inefficiencies in producing white light emission.

Innovation Solution

A light-emitting device design that integrates a luminescence layer with a phosphor within the device, eliminating the need for additional phosphor in the package and improving thermal stability through a reflective layer and conductive support member, allowing for direct and indirect light emission to produce white light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If phosphor is applied onto the light-emitting chip in the package fabrication process, then white light can be produced, but the phosphor application becomes non-uniform and vulnerable to heat

Engineering Contradiction:
Improvewhite light productionVSAvoidphosphor heat vulnerability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The phosphor layer is formed on the light-emitting chip before packaging, allowing uniform phosphor distribution to be achieved during the chip fabrication process rather than during subsequent packaging. This preliminary action ensures consistent phosphor application and positioning, eliminating the non-uniformity problem that occurs when phosphor is applied later in the packaging process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The phosphor layer formation is merged with the light-emitting chip fabrication process. By integrating phosphor deposition into the chip manufacturing sequence (forming phosphor layer 140 on the light-emitting chip 170), the process achieves both chip fabrication and phosphor application in one unified process flow, ensuring uniformity and reducing thermal exposure during separate packaging steps.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If phosphor is applied in the form of a mixture with transparent silicone, then phosphor can be positioned, but it becomes vulnerable to heat generated by the light-emitting chip

Engineering Contradiction:
Improvephosphor positioningVSAvoidheat vulnerability
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The phosphor is extracted from the transparent silicone mixture approach and applied as a distinct phosphor layer 140 formed directly on the light-emitting chip 170. This separation eliminates the need for phosphor to be mixed with silicone, thereby removing the thermal vulnerability associated with the silicone-phosphor composite while maintaining ease of positioning through direct layer formation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a luminescence layer is integrated within the light-emitting device, then thermal stability is improved, but the device structure becomes more complex

Engineering Contradiction:
Improvethermal stabilityVSAvoiddevice structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The luminescence layer 140 containing phosphor is merged with the light-emitting chip 170 structure, forming an integrated unit where the phosphor layer is deposited directly on the chip surface. This integration achieves thermal stability by eliminating separate phosphor packaging steps while maintaining relatively simple device architecture through the unified chip-luminescence structure.

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

This design enhances light emission efficiency, reduces phosphor-related packaging issues, and improves thermal stability, resulting in a more reliable and efficient white light output with adjustable color temperature.

Implementation Method 1

a reflective layer (130) arranged on the support member (110), a luminescence layer (140) arranged on the reflective layer (130)

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a luminescence layer (140) arranged on the reflective layer (130)... allowing for direct and indirect light emission to produce white light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP2388839B1Light emitting device with wavelength conversion layer between a reflective layer and the light-emitting diode layers.
Publication Date: 2020.04.29 LG INNOTEK CO LTD
  • EP2388839B1 patent drawingFigure 1~2
  • EP2388839B1 patent drawingFigure 3~4
  • EP2388839B1 patent drawingFigure 5a~5b

AI summary

Disclosed is a light-emitting device (10) comprising a reflective layer (2); a light-emitting structure (4) on the reflective layer, the light-emitting structure including a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer and a luminescence layer (3) interposed between the reflective layer and the light-transmitting electrode layer. Accordingly, the luminescence layer is formed in the chip formation process to minimize non-uniform application of a phosphor composed of an epoxy resin and simplify fabrication of the light-emitting device.