LED Chip Thermal Management Using Resin Sheet Connecting Member
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Solution Overview
Problem
Conventional light-emitting devices face challenges in effectively dissipating heat generated by LED chips, leading to limited power output and increased junction temperatures, which restricts the lifespan and efficiency of the devices, especially when using a rubber sheet-shaped heat radiation sheet that can cause adhesion issues and air spaces, resulting in high heat resistance.
Innovation Solution
A light-emitting device design featuring a sheet-shaped connecting member with electrical insulating properties that thermally connects the heat transfer plate to a metal member, reducing heat resistance and allowing for improved heat radiation, while using a conductive substrate like SiC to enhance thermal conductivity and a sub-mount member to alleviate stress from linear expansion coefficient differences, and a resin sheet with fillers for enhanced adhesion and flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber sheet-shaped heat radiation sheet is interposed between the metal plate and the body of the luminaire to ensure lighting surge protection, then electrical insulation is improved, but heat resistance increases and heat dissipation efficiency deteriorates
Solution Approach 1:
The patent changes the material parameters of the insulating layer from rubber sheet to resin sheet with specific filler content (30-70 vol%). This parameter change maintains electrical insulation for lighting surge protection while significantly improving thermal conductivity to reduce heat resistance and enhance heat dissipation efficiency.
Solution Approach 2:
The patent uses a composite material consisting of resin sheet combined with inorganic fillers (such as aluminum oxide, aluminum nitride, or boron nitride) to create an insulating layer that simultaneously provides electrical insulation and high thermal conductivity, resolving the contradiction between electrical protection and heat dissipation.
2Device complexity
If the heat transfer member size is reduced to match the LED chip size, then device complexity is reduced, but heat resistance from LED chip to metal plate increases
Solution Approach 1:
The patent extends the heat transfer path in the planar dimension by making the heat transfer member larger than the LED chip. This dimensional approach allows heat to be collected from the entire LED chip area and distributed over a larger area of the metal plate, reducing heat resistance without increasing vertical device complexity.
3Productivity
If multiple white LEDs are mounted on one circuit board to form an LED unit to achieve desired light output, then productivity is improved, but heat dissipation becomes more difficult and temperature control deteriorates
Solution Approach 1:
The patent segments the heat dissipation function by providing individual heat transfer members for each LED chip, with each heat transfer member directly connected to the metal plate. This segmentation allows independent heat management for each LED, enabling multiple LEDs to be mounted on one circuit board while maintaining effective heat dissipation for each individual chip.
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 reduces heat resistance, prevents junction temperature rise, extends the lifespan of LED chips, and increases power output while providing improved lighting surge protection and reliability by enhancing heat radiation properties and reducing variations in heat resistance.
Implementation Method 1
a sheet-shaped connecting member which is disposed on the other surface side of the heat transfer plate to connect the heat transfer plate to a metal member for holding the chip mounting member and has an electrical insulating property and thermally connects the heat transfer plate and the metal member to each other
Implementation Method 2
a resin sheet with fillers for enhanced adhesion and flowability
Data Source
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AI summary
A light-emitting device of the present invention includes: a LED chip 10; a chip mounting member 70 having a conductive plate (heat transfer plate) 71 one surface side of which the LED chip 10 is mounted on and a conductor patterns 73, 73 which is formed on the one surface side of the conductive plate 71 through an insulating part 72 and electrically connected to the LED chip 10; and a sheet-shaped connecting member 80 disposed on the other surface side of the conductive plate 71 to connect the conductive plate 71 to a body of the luminaire 90 which is a metal member for holding the chip mounting member 70. The connecting member 80 is made of a resin sheet which includes a filler and whose viscosity is reduced by heating, and the connecting member 80 has an electrical insulating property and thermally connects the conductive plate 71 and the body 90 of the luminaire to each other.