Sapphire LED Chips on Reflective Submounts for High Density Arrays
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Solution Overview
Problem
Conventional LED products face challenges in achieving high density arrays due to wire bonds, which result in light absorption and reduced luminous flux, and silicon carbide-based chips further restrict density due to light absorption, necessitating a solution for brighter, more efficient, and cost-effective LED components.
Innovation Solution
The use of a reflective material over a submount with sapphire-based LED chips, allowing for tighter packing and improved light extraction, as the reflective material covers portions of the submount and the chips are spaced closely, maximizing the ratio of combined epi area to reflective surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonds are used to electrically connect LED chips, then electrical connectivity is achieved, but light absorption increases and luminous flux decreases
Solution Approach 1:
The patent removes wire bonds from the LED array structure entirely, replacing them with a substrate-based electrical connection system. This extraction eliminates the harmful light-absorbing wire bonds while maintaining electrical connectivity through alternative means (substrate traces and contacts), directly resolving the contradiction between achieving electrical connectivity and minimizing light loss.
2Productivity
If SiC-based chips are used in arrays, then electrical and optical functionality is achieved, but light absorption increases when chips are spaced closely, constraining array density
Solution Approach 1:
The patent changes the substrate material parameter from SiC to sapphire for the LED chips themselves. Sapphire has superior optical transparency compared to SiC, allowing light to pass through the chip substrate without significant absorption. This parameter change enables high array density while minimizing light loss, as closely spaced chips no longer suffer from mutual light absorption through their substrates.
3Productivity
If chips are spaced closely to increase array density, then productivity is improved, but wire bonds and SiC substrates create constraints on achievable density
Solution Approach 1:
The patent merges the electrical connection function and the mechanical support function into a single integrated substrate structure. The substrate provides both structural support for mounting chips and electrical pathways for connecting them, eliminating the need for separate wire bonds. This merging simplifies the overall structure and enables higher array density by removing the space and complexity constraints imposed by wire bonding infrastructure.
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 enhances light extraction and brightness while reducing costs, enabling higher density arrays with minimal light absorption, leading to more efficient and cost-effective LED components.
Implementation Method 1
a reflective material disposed over portions of the submount. The reflective material comprises a reflective surface
Data Source
AI summary
Light emitter components and related methods are provided. In some aspects, light emitter components and related methods include a ceramic submount having a reflective surface. Light emitter components and related methods can include light emitter chips disposed over the reflective surface. Each light emitter chip can include a sapphire substrate, an epi area disposed over the sapphire substrate, and first and second electrical contacts disposed over the epi area. The first and second electrical contacts may face the reflective surface. A ratio between a combined epi area of the plurality of light emitter chips and a surface area of the reflective surface may be at least 0.4 or more, and a ratio between a combined planar surface area of the plurality of light emitter chips and a planar surface area of the reflective surface may be at least approximately 0.25 or more.