LED Active Area Spacing for Thermal Management

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Solution Overview

Problem

Conventional light emitting devices experience deteriorated heat radiation and reduced luminous efficacy due to overlapping active areas, which impede efficient heat dissipation and light emission.

Innovation Solution

The light emitting device design features active areas spaced apart from each other by specific distances, with strategically placed bumps and a reflective layer to enhance heat radiation and luminous efficacy, and is packaged with a header and molding member for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If active areas are disposed in contact with each other to increase light emission area, then luminous output is improved, but heat radiation deteriorates

Engineering Contradiction:
Improveluminous outputVSAvoidheat radiation
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The light emitting device divides the active areas into separate, non-contacting regions spaced apart from each other. This segmentation prevents the overlapping of active areas while maintaining sufficient light emission area, thereby resolving the contradiction between achieving high luminous output and ensuring effective heat radiation.

Inventive Principle:
Principle #1Segmentation

2Temperature

If active areas are spaced apart to improve heat radiation, then heat dissipation is improved, but luminous output decreases

Engineering Contradiction:
Improveheat radiationVSAvoidluminous output
Core Design Contradiction:
TemperatureVSIllumination intensity

Solution Approach 1:

The patent optimizes the spacing distance between active areas within a specific range (60μm to 300μm) to achieve the best balance between heat radiation and luminous output. By carefully controlling this parameter, the device maintains effective heat dissipation while preserving sufficient light emission area for high luminous output.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If active areas are spaced apart from edges to improve heat radiation, then thermal management is improved, but device area increases

Engineering Contradiction:
Improveheat radiationVSAvoiddevice area
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The patent specifies optimal spacing distances between active areas and device edges (10μm to 100μm) to achieve effective heat radiation without excessive increase in device area. This parameter optimization ensures proper thermal management while maintaining compact device dimensions.

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 design achieves better heat radiation and luminous efficacy by spacing active areas and using a reflective layer, resulting in enhanced light emission and thermal management within the light emitting device package.

Implementation Method 1

at least one first bump disposed between the first conductive semiconductor layer and the first metal pad and at least one second bump located between the second conductive semiconductor layer and the second metal pad

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The light emitting device may further include a reflective layer disposed between the second bump and the second conductive semiconductor layer

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2860778B1Multi-area light emitting diode, light emitting device package including the diode and lighting apparatus including the package
Publication Date: 2020.12.09 SUZHOU LEKIN SEMICON CO LTD
  • EP2860778B1 patent drawingFigure 1A
  • EP2860778B1 patent drawingFigure 1B
  • EP2860778B1 patent drawingFigure 2

AI summary

Embodiments provide a light emitting device (100A) including a substrate (110), a light emitting structure (120) disposed under the substrate, the light emitting structure including a first conductive semiconductor layer (122), an active layer (124) and a second conductive semiconductor layer (126), a sub-mount (140), first and second metal pads (152, 154) disposed on the sub-mount and electrically spaced apart from one another, a one first bump (162) disposed between the first conductive semiconductor layer and the first metal pad (152) and a second bump (164) located between the second conductive semiconductor layer and the second metal pad (154) . A plurality of active areas containing the first semiconductor layer (122) and the active layer (124) are spaced apart from one another when viewed from above.