Light Emitting Device Heat Conductive Layer Thermal Resistance Reduction
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Solution Overview
Problem
Existing light emitting devices face high thermal resistance due to the use of materials with low thermal conductivity, such as printed circuit boards and leadframes, which hampers heat dissipation and reduces device efficiency and lifespan.
Innovation Solution
A light emitting device design featuring a heat sink with a dielectric layer and a heat conductive layer, where the light emitting chip is directly attached using an undercoating, allowing for efficient heat transfer from the chip to the heat sink through a thermally conductive undercoating, potentially with an electrically conductive undercoating and contact points for enhanced energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional leadframe or printed circuit board structures are used, then device assembly is simplified, but thermal resistance increases and heat dissipation efficiency deteriorates
Solution Approach 1:
The patent merges the support structure and heat dissipation function into a single integrated heat conductive layer, eliminating the need for separate leadframes or printed circuit boards. This integration directly reduces thermal resistance while maintaining structural support, resolving the contradiction between assembly simplicity and heat dissipation efficiency.
Solution Approach 2:
The heat conductive layer serves multiple functions simultaneously: it provides mechanical support for the light emitting chip, conducts heat away from the chip, and serves as a mounting substrate. This multi-functionality eliminates the need for separate components, reducing both thermal resistance and device complexity.
2Ease of manufacture
If materials with low thermal conductivity (plastic, ceramic, FR4) are used in packaging and mounting, then manufacturing cost is reduced, but heat dissipation efficiency and device lifespan deteriorate
Solution Approach 1:
The patent changes the thermal conductivity parameter of the mounting structure by using a heat conductive layer with high thermal conductivity (specifically mentioning aluminum nitride with thermal conductivity of 150-200 W/mK). This parameter change enables efficient heat dissipation, directly improving device lifespan while maintaining manufacturing feasibility.
3Ease of manufacture
If conventional adhesive materials and thermal interface materials are used between chip, board, and heat sink, then manufacturing process is simplified, but thermal resistance increases and light efficiency deteriorates
Solution Approach 1:
The patent extracts and eliminates the low thermal conductivity adhesive and thermal interface materials from the heat conduction path. By directly mounting the chip to the heat conductive layer without these intermediate materials, thermal resistance is minimized, improving light efficiency while maintaining manufacturing simplicity through direct bonding processes.
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 improves thermal conductivity and reduces device complexity, enhancing light efficiency and lifespan by facilitating rapid heat dissipation and uniform energy distribution within the heat conductive layer.
Implementation Method 1
The undercoating can be also electrically conductive and part of a circuit... the energy which is produced during operating the light emitting device can easily be transferred from the chip to the heat conductive layer via the thermally conductive undercoating
Implementation Method 2
Because of the good thermal conductivity of the heat conductive layer, the heat is quickly transferred away from the chip to the dielectric layer and from there to the heat sink
Implementation Method 3
the heat which is produced during operating the light emitting device by the chip has to pass the package into the board substrate and the thermal interface material or air between the board and the heat sink until it reaches the heat sink and can be dissipated to the ambient
Implementation Method 4
the heat which is produced during operating the light emitting device by the chip has to pass the package into the board substrate and the thermal interface material or air between the board and the heat sink until it reaches the heat sink and can be dissipated to the ambient
Data Source
AI summary
A light emitting device comprising a heat sink, a dielectric layer arranged on the heat sink, a heat conductive layer arranged on the dielectric layer, an undercoating arranged on at least a part of the heat conductive layer, and a light emitting chip attached to the heat conductive layer by means of the undercoating.