LED Optical Element for Photon Recycling at High Junction Temperatures
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Solution Overview
Problem
High junction temperatures in light-emitting diodes (LEDs) cause polymer coatings to degrade, leading to reduced light emission performance due to light transmission and aperture deformation, which affects the desired light emission and quantum efficiency.
Innovation Solution
An optical element with a reflective surface for specific light spectra and an absorptive surface for complementary spectra, composed of metal and dielectric layers, is applied to the LED light emission surface, allowing for photon recycling and maintaining performance at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer coating is used on LED light emission surface, then light emission performance can be controlled, but the polymer degrades at high junction temperatures causing performance reduction
Solution Approach 1:
The patent applies composite materials by combining metal layers (for reflectivity and thermal stability) with dielectric layers (for optical control and protection) to create an optical element that maintains performance at high junction temperatures unlike single-material polymer coatings
Solution Approach 2:
The patent changes the material parameters from organic polymer to inorganic metal-dielectric composite, fundamentally altering temperature resistance properties while maintaining optical control capabilities through engineered layer structures
2Shape
If polymer coating is used to control light emission, then aperture shape can be maintained, but heat causes deformation and light transmission issues
Solution Approach 1:
The metal-dielectric composite structure provides dimensional stability at high temperatures, preventing the aperture shape deformation that occurs with polymer coatings while maintaining precise optical control
Solution Approach 2:
Instead of using a single polymer layer that deforms under heat, the patent inverts the approach by using multiple inorganic layers that are inherently more thermally stable, reversing the material selection logic
3Use of energy by moving object
If reflective coating is added to recycle photons, then quantum efficiency improves, but device complexity increases
Solution Approach 1:
The patent segments the optical element into distinct metal and dielectric layers, each performing specific functions (reflection, protection, optical control), which simplifies the design and manufacturing while achieving photon recycling and improved quantum efficiency
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 optical element enhances light emission efficiency and brightness by reflecting desired light back into the LED and absorbing unwanted light, maintaining performance over the LED's operational life without degrading, unlike polymer coatings.
Implementation Method 1
a first surface of the optical element, which contacts the light emission surface, is configured to reflect light associated with the first optical spectrum
Implementation Method 2
a second surface of the optical element, opposite the first surface of the optical element, is configured to absorb light associated with a second optical spectrum
Data Source
AI summary
An emitter includes a light emission region configured to emit light associated with a first optical spectrum, a light emission surface, and an optical element disposed on the light emission surface. A first surface of the optical element, which contacts the light emission surface, is configured to reflect light associated with the first optical spectrum. A second surface of the optical element, opposite the first surface of the optical element, is configured to absorb light associated with a second optical spectrum. At least one aperture is formed in the optical element.