Compact LED Thermal Pad Layout for Heat Dissipation Isolation
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Solution Overview
Problem
Conventional LED packages with compact sizes face challenges in achieving high light emission efficiency and heat dissipation while minimizing electrical shorting, as the required surface area for thermal pads is limited by the small size of the submount.
Innovation Solution
The LED package design includes a thermal pad positioned between the anode and cathode mounting pads, with carefully optimized distances and protrusions to maximize heat dissipation surface area while avoiding electrical shorting, utilizing a submount with dimensions less than 2 mm by 2 mm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the submount size is reduced to achieve miniaturization, then the LED package size is reduced, but the surface area available for thermal pad is limited which reduces heat dissipation efficiency
Solution Approach 1:
The thermal pad is positioned on the second side of the submount (opposite to the LED chip mounting side) and extends between the anode and cathode mounting pads. This utilizes the vertical/dimensional space on the backside of the submount rather than competing for surface area on the same plane as the electrical pads, effectively adding a dimensional solution to the area constraint problem.
Solution Approach 2:
The thermal pad is segmented into multiple regions including a first region extending between the anode and cathode mounting pads, and a second region extending toward a peripheral edge of the submount. This segmentation allows the thermal pad to maximize its surface area within the constrained space by utilizing different zones of the submount's second side.
2Temperature
If the thermal pad surface area is increased to improve heat dissipation, then heat dissipation efficiency is improved, but the risk of electrical shorting between thermal pad and mounting pads increases
Solution Approach 1:
The thermal pad is positioned between the anode and cathode mounting pads on the second side of the submount, using the submount structure itself as an intermediary barrier. The thermal pad's first region extends between the mounting pads while maintaining spacing, and the submount's insulating properties prevent electrical shorting while allowing thermal conduction.
Solution Approach 2:
The thermal pad has different regional configurations: a first region that extends between the anode and cathode mounting pads with controlled spacing, and a second region that extends toward the peripheral edge. This local differentiation allows maximum thermal area while maintaining electrical isolation in critical zones.
3Area of stationary object
If the distance between thermal pad and mounting pads is reduced to maximize thermal pad area, then heat dissipation surface area is increased, but electrical shorting between thermal pad and mounting pads occurs
Solution Approach 1:
The thermal pad utilizes the second side of the submount (opposite the LED chip side) to establish its position and area. By moving the thermal pad to this different dimensional plane, the design achieves maximum surface area without reducing the spacing to mounting pads, as the thermal pad and mounting pads are on opposite sides of the submount thickness dimension.
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 effectively enhances thermal dissipation and reduces electrical shorting risks, maintaining suitable operating temperatures and improving manufacturing yields in compact LED packages.
Implementation Method 1
a thermal pad on the second side of the submount, the thermal pad arranged between the anode mounting pad and the cathode mounting pad on the second side
Data Source
AI summary
Light-emitting diode (LED) packages and more particularly thermal pad structures for LED packages with reduced sizes are disclosed. LED packages include an LED chip on a submount with an anode mounting pad, a cathode mounting pad, and a thermal pad on an opposite side of the submount to the LED chip. Structures of thermal pads and corresponding anode and cathode mounting pads include arrangements that provide shortest distances values between the thermal pads and the anode and cathode mounting pads that provide increased surface area for heat dissipation while also reducing electrical shorting, particularly for submounts with compact sizes.