Package-less LED Assembly on Single Crystal Substrate
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Solution Overview
Problem
Conventional LED assemblies for backlit units (BLUs) have a large form factor and high manufacturing costs due to the use of metal lead frame packages and multiple manufacturing steps, making it difficult to reduce the size and cost of these assemblies.
Innovation Solution
The development of an LED assembly that eliminates the lead frame package and wire bonds, using a single crystal substrate with a plurality of LEDs in immediate physical contact, where each LED is crystal lattice matched with the substrate, and employing dielectric layers and phosphor-containing encapsulant layers to produce multispectral light, with wiring structures and vias to facilitate electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal lead frame package is used to assemble LEDs, then the structural stability and electrical connectivity are improved, but the form factor and manufacturing cost increase
Solution Approach 1:
The patent removes the metal lead frame package from the LED assembly, extracting the problematic component that caused large form factor and high cost. The LEDs are directly mounted on a substrate without the intermediate lead frame structure, eliminating its space-consuming and costly characteristics while maintaining functional requirements through alternative design approaches.
Solution Approach 2:
The patent merges the substrate function with the mounting function, combining what were previously separate components (substrate and lead frame) into a single integrated substrate structure. This consolidation eliminates the need for the lead frame package while maintaining both structural support and electrical connectivity functions in a more compact form.
2Reliability
If a metal lead frame package with multiple manufacturing steps is used, then the electrical connectivity and structural support are improved, but the manufacturing cost increases
Solution Approach 1:
The patent combines multiple manufacturing functions into fewer steps by directly mounting LEDs on the substrate without requiring separate lead frame assembly, wire bonding, and packaging operations. This integration of mounting and electrical connection functions reduces the number of manufacturing steps and associated costs.
Solution Approach 2:
The patent extracts and eliminates the metal lead frame package and wire bonding steps from the manufacturing process. By removing these expensive and time-consuming intermediate components and processes, the manufacturing cost is reduced while electrical connectivity is achieved through direct substrate contact.
3Strength
If conventional LED assemblies with lead frame packages are used, then the structural integrity is improved, but the form factor and complexity increase
Solution Approach 1:
The patent extracts and removes the complex lead frame package structure from the LED assembly. By eliminating this multi-component structural element, the overall assembly complexity is reduced while structural integrity is maintained through the simplified direct-mount substrate design.
Solution Approach 2:
The patent merges the structural support function and electrical connection function into a single substrate, eliminating the need for separate lead frame components. This consolidation reduces assembly complexity by reducing the number of parts and interfaces while maintaining structural integrity.
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 approach results in a smaller form factor and lower manufacturing costs, enabling thinner and more cost-effective BLUs with reduced size and complexity, while maintaining efficient light production and addressability of individual LEDs.
Implementation Method 1
two or more phosphor-containing encapsulant layers
Data Source
AI summary
This application describes an assembly suitable for emitting light, and methods of forming the same. The assembly includes a single crystal substrate with first and second surfaces, a plurality of LEDs in immediate contact with the first surface of the substrate. The LEDs are substantially crystal lattice matched with the substrate. The plurality of LEDs includes three or more LEDs that are not in electrical contact with any other LED, and there is a gap between each LED of the plurality and its nearest neighbor LED. The assembly includes phosphor-containing encapsulant layers overlying at least a portion of the LEDs.