LED Package with Discrete Active Layers for Light Extraction
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Solution Overview
Problem
Conventional LED packages face challenges with light extraction efficiency due to internal reflection, leading to optical losses and suboptimal illumination characteristics, as photons are either refracted or internally reflected, ultimately absorbed and not contributing to visible light output.
Innovation Solution
The proposed LED package design features a monolithic substrate with multiple discrete active layer portions and a submount, incorporating wavelength conversion elements and light-altering materials to improve light extraction and alignment, reducing optical losses by redirecting laterally emitting light towards a desired emission direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LED packages are used, then manufacturing is simpler, but light extraction efficiency is poor due to internal reflection causing optical losses
Solution Approach 1:
The active layer is divided into multiple discrete active layer portions that are arranged in a specific pattern on the submount. This segmentation allows light emitted from different portions to exit at different angles, reducing internal reflection and improving light extraction efficiency while maintaining a relatively simple overall package structure
Solution Approach 2:
Different regions of the LED package are assigned different optical properties. The discrete active layer portions are positioned to emit light in specific directions, and the package structure incorporates elements with varying refractive indices in different locations to optimize light extraction locally and minimize optical losses
2Illumination intensity
If multiple discrete LED chips are used, then brightness can be increased, but alignment becomes more difficult and manufacturing complexity increases
Solution Approach 1:
Multiple discrete active layer portions are integrated onto a single submount in a coordinated arrangement. This merging approach achieves the brightness of multiple separate chips while eliminating alignment issues between independent chips, as all active portions are positioned relative to a common reference frame during a single manufacturing process
Solution Approach 2:
The submount serves multiple functions simultaneously: it provides mechanical support for the discrete active layer portions, establishes a common reference frame for precise positioning, facilitates electrical connections to all active portions, and enables thermal management. This multi-functionality increases brightness while simplifying manufacturing and improving alignment
3Loss of energy
If light-altering materials are added around the LED chip, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
Light-altering materials are positioned as intermediary elements between the discrete active layer portions and the external environment. These materials modify the optical path of emitted light, reducing internal reflection and improving extraction efficiency. The intermediaries are integrated into the package structure in a way that adds functionality without significantly increasing overall device complexity
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 enhances brightness, simplifies manufacturing, and reduces costs by minimizing the need for multiple discrete LED chips, while providing improved alignment and thermal contact for the LED package, resulting in increased luminance and efficiency.
Implementation Method 1
a wavelength conversion element on the monolithic substrate
Implementation Method 2
According to the well-understood implications of Snell's law, photons reaching the surface (interface) between an LED surface and the surrounding environment are either refracted or internally reflected
Implementation Method 3
photons reaching the surface (interface) between an LED surface and the surrounding environment are either refracted or internally reflected
Data Source
AI summary
Solid-state light emitting devices including light-emitting diodes (LEDs), and more particularly packaged LEDs are disclosed. LED packages are disclosed that include an LED chip with multiple discrete active layer portions mounted on a submount. The LED packages may further include wavelength conversion elements and light-altering materials. The multiple discrete active layer portions may be electrically connected in series, parallel, or in individually addressable arrangements. The LED chip with the multiple discrete active layer portions may provide the LED package with improved brightness, improved alignment, simplified manufacturing, and reduced costs.