Light Emitting Device With Distributed Bragg Reflector
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Solution Overview
Problem
In arrays of small light emitting devices with wavelength-converting layers, there is a significant challenge in minimizing disturbances between adjacent devices as the pitch decreases, leading to reduced light intensity and image quality issues in applications like watches and virtual reality headsets, where reflector layers are essential to direct light efficiently and minimize interference.
Innovation Solution
The method involves forming a light emitting device with an LED and a distributed Bragg reflector (DBR) where a dielectric layer coats the LED sidewalls, and a trench is created in this layer for the DBR, which conforms to the trench walls and bottom, optimizing reflectivity to reduce disturbances between adjacent devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If light emitting devices are packed more closely together in arrays to increase density, then the device area is reduced, but light from one device disturbs adjacent devices reducing image quality
Solution Approach 1:
A wavelength-converting layer is introduced as an intermediary between the LED and the external environment. This layer absorbs light at one wavelength from the LED and re-emits light at a different wavelength, serving as a mediator that transforms the harmful direct light into useful converted light, thereby reducing light disturbance to adjacent devices while maintaining high device density
Solution Approach 2:
The patent changes the wavelength parameter of light through the wavelength-converting layer. By absorbing light at a first wavelength and emitting at a second wavelength, the system transforms the optical parameters to reduce interference between closely-packed devices, enabling higher density arrays without image quality degradation
2Loss of energy
If reflector layers are added to direct light and minimize disturbance, then luminous efficiency is improved, but device complexity increases
Solution Approach 1:
The wavelength-converting layer is merged with the LED structure to form an integrated light emitting device. This combination allows the device to simultaneously achieve wavelength conversion for reduced disturbance and maintain simple device architecture, improving luminous efficiency without significantly increasing complexity
Solution Approach 2:
The wavelength-converting layer serves multiple functions: it converts wavelength to reduce light disturbance, directs light in useful directions, and maintains adhesion to the LED structure. This multi-functionality improves luminous efficiency while avoiding the need for separate reflector layers that would increase 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 configuration effectively minimizes disturbances between light emitting devices, enhancing luminous efficiency and maintaining image quality even at small pitches, suitable for high-density arrays in various display applications.
Implementation Method 1
a distributed Bragg reflector (DBR)... DBRs are particularly useful as reflectors in light emitting devices as their composition may be optimized to reflect light of a particular wavelength or wavelengths
Implementation Method 2
Light emitting devices that have both an LED and an W-CL, wherein the W-CL absorbs light of one dominant wavelength from the LED and re-emits light with a different dominant wavelength
Data Source
AI summary
This application describes a light emitting device or an assembly of light emitting devices. In the completed light emitting device, a distributed Bragg reflector minimizes the possibility of disturbing adjacent light emitting devices. Methods to fabricate such devices and assemblies of devices are also described.