Light Emitting Apparatus Thermal Dissipation via Exposed Leads
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Solution Overview
Problem
High-power light emitting devices face issues with heat management and reliability due to uneven heat distribution, leading to potential cracks and reduced lifespan, especially in devices with short wavelength light emission, where the wavelength conversion member generates increased heat and causes thermal stress.
Innovation Solution
A light emitting apparatus design featuring a base and leads with exposed portions for thermally conductive heat dissipation, where the first resin molding member covers the base and leads, and the second resin molding member embeds protection devices to prevent light absorption and enhance heat dispersion, ensuring even heat distribution and reduced thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output of light emitting device is increased to enhance light power, then the light emission efficiency is improved, but heat generation increases causing device characteristic deterioration and reduced reliability
Solution Approach 1:
The patent extracts the harmful heat from the system by providing dedicated heat dissipation paths through leads with exposed portions that extend beyond the resin molding members, allowing heat to be conducted away from the light emitting device without compromising the sealed structure
Solution Approach 2:
The patent introduces resin molding members as intermediary structures that cover and protect the leads while maintaining heat dissipation functionality, acting as a mediator between the heat-generating light emitting device and the external environment
2Reliability
If heat dissipation structures are added to manage thermal stress, then reliability is improved, but device complexity increases
Solution Approach 1:
The leads serve multiple functions: electrical connection, mechanical support, and heat dissipation. The exposed portions of the leads provide thermal conduction pathways without requiring separate heat sink components, reducing overall device complexity while maintaining reliability
Solution Approach 2:
The patent merges the heat dissipation function with the existing lead structure by providing exposed portions that extend beyond the resin molding members, combining thermal management with electrical connection functions in a single integrated design
3Reliability
If resin molding members cover the leads completely, then protection is improved, but heat dissipation is reduced
Solution Approach 1:
The resin molding members provide complete coverage and protection for most of the leads, but leave specific portions (the exposed portions) uncovered to maintain heat dissipation functionality, applying different levels of coverage based on local requirements
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 improves heat resistance and reliability by uniformly dispersing heat, reducing light loss, and minimizing stress between different material boundaries, resulting in a high-power, long-lasting light emitting apparatus with enhanced heat dissipation characteristics.
Implementation Method 1
the first resin molding member covers the base and leads, and the second resin molding member embeds protection devices to prevent light absorption and enhance heat dispersion
Implementation Method 2
a light emitting apparatus includes a light emitting device, a base, a first lead and a second lead
Data Source
AI summary
A light emitting apparatus includes a light emitting device mounted on a base. First and second leads are electrically connected to the light emitting device. A first resin molding member formed of thermosetting resin covers at least partially the base and the first and second leads so that the first resin molding member is formed integrally with the base and the first and second leads. A second resin molding member formed of thermosetting resin is in contact with at least a part of the first resin molding member and covers the light emitting device. A recessed portion is formed in the first resin molding member on a light emitting device mount surface side of the base to open upward and to have a side surface. A protection device is mounted on the first lead or the second lead. The protection device is covered by the first resin molding member.