Flip Chip LED Transparent Substrate Surface Features
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Solution Overview
Problem
Conventional flip chip light emitting diodes (LEDs) have limited light extraction efficiency, which hinders their performance in various lighting applications, and their architecture often complicates integration into existing LED packages and assemblies.
Innovation Solution
The development of flip chip LEDs with a substrate or carrier made from a rigid transparent material, featuring surface projections on both the active material interface and the outer surface to enhance light extraction, along with the option of epitaxial growth and wavelength conversion materials like phosphor, to improve light extraction efficiency and compatibility with existing LED packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flip chip LED constructions are used, then the architecture is compatible with existing LED packages, but the light extraction efficiency is limited
Solution Approach 1:
The patent applies local quality by introducing surface features (protrusions or recesses) at specific locations on the substrate surfaces. These localized structural modifications create regions with different optical properties that enhance light extraction efficiency without changing the overall LED architecture, maintaining compatibility with existing packages while improving local light extraction performance.
Solution Approach 2:
The patent introduces a new dimension to the substrate surface by adding three-dimensional surface features (protrusions or recesses). This dimensional modification creates additional light extraction pathways and reduces total internal reflection, thereby improving light extraction efficiency while preserving the fundamental flip chip structure for compatibility with existing LED packages.
2Illumination intensity
If surface features are added to the transparent material, then light extraction efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the physical parameters of the substrate surface, specifically introducing protrusions or recesses with controlled dimensions (e.g., depth of 1-10 micrometers). These parameter modifications enhance light extraction efficiency through optical effects while maintaining a relatively simple structural addition that does not overly complicate the device architecture.
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 enhanced light extraction efficiency of the modified flip chip LEDs allows for improved light emission, reduced blue leakage, and cost-effective wavelength control, making them more suitable for end-use lighting applications while simplifying integration into existing assemblies.
Implementation Method 1
A second surface of the transparent material oriented opposite the first surface comprises a number of surface features for minimizing total internal reflection of light passing through the transparent material to the second surface
Implementation Method 2
active materials known to produce light in a particular wavelength, e.g., a blue wavelength, when subjected to a power source to initiate current flow through the flip chip thereby causing the emission of light therefrom
Implementation Method 3
option of epitaxial growth and wavelength conversion materials like phosphor
Data Source
AI summary
Flip chip LEDs include a transparent substrate or carrier having an active material attached thereto and having a number of electrodes disposed along a common surface of the active material. The substrate may include a number of surface features disposed along a first surface adjacent the active material for improving light extraction from the active material, and includes a number of surface features along a second surface opposite the first surface for minimizing internal reflection of light through the substrate, thereby improving light extraction from the transparent substrate. The surface features on both surfaces may be arranged having a random or ordered orientation relative to one another. A plurality of such flip chip LEDs may be physically packaged together in a manner providing electrical connection with the same for a lighting end-use application.