Micro-LED Resonant Micro-Cavity for Directional Pixel Emission
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Solution Overview
Problem
Conventional LED devices in Micro-LED displays suffer from large emission angles, leading to reduced pixel brightness, color contrast, and increased heat and power consumption, which are undesirable for portable Mixed Reality devices like AR glasses.
Innovation Solution
The implementation of a resonant micro-cavity structure in micro-LED devices, combined with concave surfaces and micro-lenses, to promote directional light emission, improve optical efficiency, and reduce energy consumption by collimating light and suppressing unwanted optical modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED devices are used, then the device structure is simple, but the emission angle is large causing reduced pixel brightness and contrast
Solution Approach 1:
The patent embeds a resonant micro-cavity structure within the LED device, nesting multiple functional components (distributed Bragg reflector, quantum well, concave mirror) within a compact vertical architecture. This nesting approach achieves directional emission and improved brightness without significantly increasing lateral device footprint
Solution Approach 2:
The patent employs concave curved surfaces (parabolic or spherical mirrors) within the micro-cavity structure to focus and direct light emission. The curved geometry concentrates light rays into a narrower emission angle, improving pixel brightness and contrast while maintaining a compact device structure
2Use of energy by moving object
If conventional LED devices with large emission angles are used, then the device is simple, but heat and power consumption increase
Solution Approach 1:
The patent converts the naturally omnidirectional light emission (which causes energy waste) into a beneficial directional beam through the micro-cavity structure. The distributed Bragg reflector and concave mirror work together to redirect previously wasted light into useful directional emission, reducing the power needed to achieve target brightness levels
Solution Approach 2:
The patent fundamentally changes the emission parameter (angular distribution) of the LED from wide-angle to narrow-angle through the resonant micro-cavity design. This parameter transformation improves energy efficiency by concentrating optical power in the desired direction, reducing the total power consumption required for display operation
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 approach significantly enhances brightness, reduces optical power requirements, and increases the useful optical power collected by the display system, leading to improved system efficiency and extended battery life in portable devices.
Implementation Method 1
a resonant micro-cavity formed about the quantum well between the distributed Bragg reflector and the optically reflective surface of the second contact, wherein the distributed Bragg reflector corresponds to a top reflector of the resonant micro-cavity and the optically reflective surface corresponds to a bottom reflector of the resonant micro-cavity
Implementation Method 2
one or more of the optically reflective surface and the distributed Bragg reflector are concavely shaped such that the resonant micro-cavity promotes vertical light propagation and confines horizontal light propagation
Implementation Method 3
a distributed Bragg reflector located about an aperture region of the top portion of the device... an optically reflective surface of the second contact... wherein the distributed Bragg reflector corresponds to a top reflector of the resonant micro-cavity and the optically reflective surface corresponds to a bottom reflector of the resonant micro-cavity
Implementation Method 4
Micro-lenses can be used to further enhance the desirable light collimation effects of the described devices
Data Source
AI summary
Technologies are described for micro-LED devices that employ a resonant micro-cavity structure to promote direction emission. The described techniques facilitate a narrowed emission spectra, with improved optical efficiency and reduced energy consumption. The light emission profiles are collimated by the cavity effect in the LED, yielding improving brightness and significantly reducing the required optical power to achieve the desired brightness. The described resonant micro-cavity structures emit light for certain desired optical modes, while suppressing certain other modes that are not desired. Concave surfaces in the resonance micro-cavity structures may be used to further confine light propagation in the horizontal direction, achieve better collimation, and reduce pixel level crosstalk. Micro-lenses can be used to further enhance the desirable light collimation effects of the described devices.