LED Lamp Thermal Resistance Reduction via Exposed Metal Plate
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Solution Overview
Problem
Conventional LED lamp packaging faces inefficiencies in heat dissipation due to the lead frame being sandwiched within a thermally insulative plastic casing, limiting the main thermal path and leading to increased device temperatures, which can cause degradation and affect optical properties.
Innovation Solution
The LED structure incorporates a metal substrate with a primary and secondary metal plate, both thermally and electrically connected via bonding layers, exposed through the casing for enhanced heat transfer, allowing direct connection to a heat sink for improved thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead frame is enclosed within the plastic casing for structural support and electrical insulation, then the mechanical stability and electrical isolation are improved, but the thermal dissipation is worsened due to the thermally insulative plastic casing limiting the main thermal path
Solution Approach 1:
The invention divides the thermal management system into two independent paths: the original lead frame path enclosed in plastic for structural support, and a new dedicated thermal path using metal plates exposed through the casing bottom. This segmentation allows each path to specialize - the lead frame provides mechanical support while the metal plates provide thermal dissipation, resolving the contradiction between structural integrity and heat dissipation.
Solution Approach 2:
The invention introduces metal plates as intermediary elements that bridge the thermal gap created by the plastic casing. These metal plates serve as thermal conduits that extend from the LED chip through the plastic casing to the external environment, mediating the thermal transfer without compromising the plastic casing's structural and insulative functions.
2Temperature
If the lead size is increased to promote heat transfer, then the thermal conduction capability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention extracts the thermal dissipation function from the lead frame structure. Instead of modifying the lead frame to increase its thermal capability, the thermal dissipation function is separated and implemented through dedicated metal plates that are simpler in structure and can be optimized independently for heat transfer without increasing overall device complexity.
3Use of energy by moving object
If high currents are used to increase luminous output, then the lighting efficiency is improved, but the device temperature increases due to insufficient heat transfer
Solution Approach 1:
The invention adds a new spatial dimension for heat dissipation by extending metal plates through the bottom of the plastic casing to external heat sinks. This creates a third-dimensional thermal pathway that operates independently from the traditional planar lead frame path, enabling high current operation with effective thermal management in multiple directions.
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 configuration reduces thermal resistance and enhances heat-sinking capabilities, mitigating temperature-related issues and maintaining optical performance by facilitating more effective heat dissipation.
Implementation Method 1
Heat transfer management is a concern for designers of light-emitting diode (LED) lamps that wish to increase efficiency... insufficient heat transfer from the p-n junction of the semiconductor active layer to the ambient environment... The main path for heat dissipation (thermal path) in prior art is from the p-n junction to the lead frame and then through the ends of the leads via heat conduction
Implementation Method 2
a primary metal plate electrically and thermally conductively connected to the metal substrate via a metal bonding layer
Data Source
AI summary
A light-emitting diode (LED) structure with an improved heat transfer path with a lower thermal resistance than conventional LED lamps is provided. For some embodiments, a surface-mountable light-emitting diode structure is provided having an active layer deposited on a metal substrate directly bonded to a metal plate that is substantially exposed for low thermal resistance by positioning it on the bottom of the light-emitting diode structure. This metal plate can then be soldered to a printed circuit board (PCB) that includes a heat sink. For some embodiments of the invention, the metal plate is thermally and electrically conductively connected through several heat conduction layers to a large heat sink that may be included in the structure.