Micro-LED Display Package Structure for Heat Dissipation and Planarity
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Solution Overview
Problem
Micro-LED display packages face challenges in managing thermal resistance and planarity, which affect the performance and reliability of micro-LED-based display systems, particularly in applications like near-eye displays where high heat generation and mechanical stability are critical.
Innovation Solution
Incorporating a spacer structure with high thermal conductivity, such as Si, Mo, AlN, or Cu, within the molding compound of the display package, along with a backplane die, to provide mechanical support and planar alignment for the micro-LEDs, while enhancing thermal dissipation and maintaining planarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a molding compound is used to encapsulate the LED dies and backplane die, then mechanical protection and structural integrity are improved, but thermal resistance increases and thermal dissipation deteriorates
Solution Approach 1:
The patent employs a composite structure combining molding compound with high thermal conductivity spacer structures. The molding compound provides mechanical encapsulation and protection, while the spacer structures (made from materials like AlN, Cu, or Mo with thermal conductivity ≥50 W/m·K) embedded within it create thermal pathways for heat dissipation. This composite approach resolves the contradiction by allowing each material to fulfill its optimal function.
Solution Approach 2:
The spacer structures act as intermediary elements between the heat-generating LED dies and the external environment. These spacers serve as thermal conduits that mediate heat transfer through the otherwise thermally resistive molding compound, enabling effective thermal management while maintaining the mechanical benefits of encapsulation.
2Illumination intensity
If the LED dies are arranged on the top surface of the display package, then light emission and display functionality are improved, but planarity control becomes difficult and mechanical stability deteriorates
Solution Approach 1:
The spacer structures are pre-formed and positioned within the molding compound before the LED dies are mounted. These spacers establish the planar geometry and mechanical support framework in advance, ensuring that when LED dies are arranged on the top surface for light emission, the underlying planarity and mechanical stability are already secured by the pre-positioned spacer structures.
Solution Approach 2:
The combination of molding compound and high thermal conductivity spacer structures creates a composite substrate that simultaneously provides mechanical support for planarity control and enables thermal management, allowing LED dies to be arranged on the top surface for optimal light emission without compromising planarity.
3Temperature
If high thermal conductivity materials (≥50 W/m·K) are used for spacer structures, then thermal dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
Rather than requiring the entire molding compound to have high thermal conductivity, the patent segments the thermal management function by embedding discrete spacer structures within the molding compound. These segmented high thermal conductivity elements (with conductivity ≥50 W/m·K) are positioned strategically to create thermal pathways, reducing manufacturing complexity compared to requiring uniform high thermal conductivity throughout the entire encapsulant.
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 solution effectively improves the internal thermal resistance and planarity of the display package, ensuring better heat dissipation and mechanical stability, thereby enhancing the performance and reliability of micro-LED-based display systems.
Implementation Method 1
The at least one spacer structure has a first thermal conductivity, and the molding compound has a second thermal conductivity lower than the first thermal conductivity. The first thermal conductivity may be at least 50 W/m·K.
Data Source
AI summary
Disclosed herein is an LED device that includes a display package and a plurality of LED dies arranged on a top surface of the display package. The display package includes a molding compound, a backplane die, and at least one spacer structure, with the backplane die and the at least one spacer structure being embedded within the molding compound. In some embodiments, the plurality of LED dies includes a first die containing red LEDs, a second die containing green LEDs, and a third die containing blue LEDs. The backplane die includes driver circuits configured to drive LEDs in the plurality of LED dies, for example, LEDs of the first die, the second die, and the third die. The at least one spacer structure has a higher thermal conductivity than the molding compound and is configured to dissipate heat generated by the LEDs in the plurality of LED dies.