Semiconductor Light Emitting Device Trench Segmentation

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Solution Overview

Problem

Large-sized semiconductor light emitting elements experience reduced light extraction efficiency due to increased average distance of light travel and repeated reflections, leading to absorption of light at the interface between the substrate and semiconductor laminate, resulting in decreased intensity of emitted light.

Innovation Solution

The semiconductor laminate is divided into at least two regions by a trench penetrating the p-type and n-type semiconductor layers, with the trench width being smaller than the average particle diameter of fluorescent particles, allowing for improved light extraction and reduced deposition of fluorescent particles within the trenches, thereby enhancing light extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the size of the semiconductor light emitting element is increased, then the number of elements that can be formed from one wafer is decreased, but the light extraction efficiency is also reduced due to increased average distance of light travel and repeated reflections

Engineering Contradiction:
Improvesize of semiconductor light emitting elementVSAvoidlight extraction efficiency
Core Design Contradiction:
Area of moving objectVSLoss of energy

Solution Approach 1:

The semiconductor laminate is divided into a plurality of semiconductor regions by trenches, creating multiple smaller light emission zones within the large-sized element. This segmentation reduces the average distance light must travel to reach the side surface, decreasing the number of reflections and improving light extraction efficiency while maintaining the large overall element size for high wafer utilization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates non-uniform light extraction characteristics by introducing trenches at specific locations within the semiconductor laminate. The trenches are strategically positioned to create regions with different light extraction properties, optimizing the overall light extraction efficiency across the large-sized element by addressing local variations in light travel distance

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If fluorescent particles are used for wavelength conversion, then white light emission is achieved, but the particles may enter gaps between small-sized elements and interrupt emitted light, deteriorating light extraction efficiency

Engineering Contradiction:
Improvewhite light emissionVSAvoidlight extraction efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The invention extracts or removes the problematic gaps between elements by forming a continuous semiconductor laminate structure divided into regions. By eliminating the gaps where fluorescent particles could accumulate and interrupt light, the design allows fluorescent particles to be uniformly distributed in the resin without causing light interruption, thus maintaining both white light emission and light extraction efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If the trench width is made larger to improve light extraction, then light extraction efficiency increases, but fluorescent particles can be deposited within the trenches, blocking light paths

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidtrench width control
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The invention optimizes the trench width parameter to a specific range (0.1 μm to 10 μm) that balances two competing requirements: wide enough to improve light extraction efficiency by reducing light travel distance, but narrow enough to prevent deposition of fluorescent particles. This precise parameter control allows the system to achieve improved light extraction without the harmful effect of particle blockage

Inventive Principle:
Principle #35Parameter changes

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 approach shortens the average distance light travels, decreases the number of reflections, and suppresses fluorescent particle deposition, resulting in improved light extraction efficiency and uniform chromaticity with good white light balance.

Implementation Method 1

fluorescent particles for wavelength conversion

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

The light reaching the side of the semiconductor laminate is emitted toward the outside of the element. In a large-sized semiconductor light emitting element, the average distance traveled by the light until it reaches the side of the semiconductor light emitting element becomes long, which increases the number of the reflections of the light before it is emitted from the light emitting element

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2660882B1Semiconductor light-emitting device
Publication Date: 2018.10.03 NICHIA CORP
  • EP2660882B1 patent drawingFigure 1A
  • EP2660882B1 patent drawingFigure 1B
  • EP2660882B1 patent drawingFigure 1C

AI summary

To provide a semiconductor light emitting device using a large-sized laminated semiconductor light emitting element with improved light extraction efficiency. The semiconductor light emitting device 90 of the present invention includes a semiconductor light emitting element 1 having a semiconductor laminate 40 including a p-type semiconductor layer 43, an active layer 42 and an n-type semiconductor layer 41 sequentially laminated, and a conductive support substrate 10 joined to the p-type semiconductor layer 43 side of the semiconductor laminate 40; a transparent sealing resin 92 covering the semiconductor laminate 40; and fluorescent particles 93 contained in the transparent sealing resin 92. The semiconductor laminate 40 is divided into at least two semiconductor regions 45a to 45d by trenches 2 penetrating the p-type semiconductor layer 43, the active layer 42, and the n-type semiconductor layer 41. The width W of the trench 2 is smaller than the average particle diameter of the fluorescent particle 93.