Solid State Lighting Package Angled Walls Thermal Management

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Solution Overview

Problem

Current solid state light packages lack enhanced light output performance, thermal management, and manufacturing ease, necessitating improved designs for solid state illumination applications.

Innovation Solution

A solid state light emission package featuring a body structure with a reflective cavity containing multiple emitters, a heatsink, and electrical leads, where the body structure is formed around a leadframe and heatsink using injection molding, with angled side and end walls to maximize frontal area and provide diffuse output, and apertures in the leads to separate electrical segments and reduce bending forces during manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If multiple solid state emitters are mounted in a package, then light output performance and flux density are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvelight output performanceVSAvoiddevice complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The package is divided into multiple functional zones: a reflective cavity for light direction, a heatsink for thermal management, and separate mounting positions for multiple emitters. This segmentation allows each component to be optimized independently while working together to achieve high light output performance without proportionally increasing overall complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple emitters are integrated into a single package structure that combines the reflective cavity, heatsink, and emitter mounting positions into one unified assembly. This merging approach achieves high flux density and improved lighting performance while managing the complexity through integrated design rather than separate components

Inventive Principle:
Principle #5Merging (Combining)

2Illumination intensity

If a reflective cavity with angled walls is used, then light output performance and diffuse output are improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvediffuse outputVSAvoidmanufacturing precision
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The reflective cavity incorporates angled side and end walls that create a controlled reflective geometry. These angled surfaces are designed to maximize the frontal area and provide diffuse light output while being manufacturable using standard molding techniques, balancing optical performance with manufacturing capability

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The angles of the side and end walls are specifically optimized to achieve the desired diffuse output characteristic. By carefully selecting these geometric parameters, the design achieves improved light distribution while remaining within the capabilities of conventional manufacturing processes

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If apertures are added to electrical leads, then ease of manufacture and bending force reduction are improved, but structural integrity may be compromised

Engineering Contradiction:
Improveease of manufactureVSAvoidstructural integrity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Apertures are introduced into the electrical leads to create segmented structures. These apertures reduce the bending forces during manufacturing by allowing the lead material to flex more easily, while the remaining material maintains sufficient structural integrity for electrical connection and mechanical support

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrical leads incorporate apertures that create a porous-like structure within the solid material. This design allows the leads to be more compliant during assembly operations while maintaining adequate strength through the surrounding material, achieving a balance between ease of manufacture and structural integrity

Inventive Principle:
Principle #31Porous materials

4Temperature

If a heatsink is integrated into the package, then thermal management is improved, but device complexity and volume increase

Engineering Contradiction:
Improvethermal managementVSAvoidpackage volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The heatsink is integrated directly into the package structure, merging the thermal management function with the mechanical housing. This integration provides effective heat dissipation for multiple emitters while minimizing the overall package volume compared to separate heatsink assemblies

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The package structure serves multiple functions: it provides mechanical support for the emitters, creates the reflective cavity for light direction, and incorporates the heatsink for thermal management. This multi-functionality reduces the need for separate components, thereby managing volume while achieving effective thermal management

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design enhances light output performance, thermal management, and manufacturing efficiency, enabling higher flux density and uniformity while allowing for higher density mounting and improved lighting performance in applications like backlit displays.

Implementation Method 1

a reflective cavity containing multiple emitters, a heatsink, and electrical leads, where the body structure is formed around a leadframe and heatsink using injection molding, with angled side and end walls to maximize frontal area and provide diffuse output

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a heatsink, and electrical leads, where the body structure is formed around a leadframe and heatsink

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2438631B1Solid state lighting device
Publication Date: 2019.04.10 WOLFSPEED INC
  • EP2438631B1 patent drawingFigure 1
  • EP2438631B1 patent drawingFigure 2
  • EP2438631B1 patent drawingFigure 3~4

AI summary

A light emission package includes at least one solid state emitter, a leadframe, and a body structure encasing a portion of the leadframe. At least one aperture is defined in an electrical lead to define multiple electrical lead segments, with at least a portion of the aperture disposed outside an exterior side wall of the package. A recess may be defined in the exterior side wall to receive a bent portion of an electrical lead. A body structure cavity may be bounded by a floor, and side wall portions and end wall portions that are separated by transition wall portions including a curved or segmented upper edge, with different wall portions being disposed at different angles of inclination.