Micro LED Optical Structure for Narrow AR/VR Beam Patterns
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Solution Overview
Problem
Conventional micro LED light patterns are not suitable for augmented reality (AR) and virtual reality (VR) applications, necessitating the development of novel micro LEDs with improved light patterns.
Innovation Solution
A micro LED structure comprising multiple micro LED chips with semiconductor stacks, metal pads, and reflective coating layers, each equipped with optical structures such as lenses or reflective cups, to modify and concentrate light emission effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional micro LED structure is used, then manufacturing is simpler, but light pattern is not suitable for AR/VR applications
Solution Approach 1:
The micro LED chip is divided into distinct functional regions: a light-emitting region with a semiconductor stack, a reflective coating layer on sidewalls, and an optical structure on the light-exiting surface. This segmentation allows each region to be optimized independently for its specific function, enabling AR/VR suitable light patterns while maintaining manufacturing feasibility through modular design.
Solution Approach 2:
Different regions of the micro LED chip are assigned different properties: the semiconductor stack provides light emission, the reflective coating layer directs light upward by reflecting downward light, and the optical structure shapes the light pattern. This local differentiation of properties enables precise control over light patterns for AR/VR applications.
2Illumination intensity
If beam angle is reduced for AR/VR applications, then light intensity is concentrated, but light distribution becomes less uniform
Solution Approach 1:
The optical structure is designed with a specific curvature radius that dynamically balances light concentration and distribution. The curved surface focuses light to increase intensity while its geometry is optimized to maintain uniform distribution across the viewing angle, achieving both high intensity and even distribution simultaneously.
Solution Approach 2:
The beam angle and light distribution characteristics are controlled by adjusting the curvature radius of the optical structure. By optimizing this geometric parameter, the system achieves narrow beam angles for light concentration while maintaining uniform light distribution across the projected image, resolving the trade-off between intensity and uniformity.
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 improved micro LED structure reduces beam angles, increases light intensity, and achieves even light distribution, making it more suitable for AR/VR applications by minimizing image crosstalk.
Implementation Method 1
a reflective coating layer is disposed around sidewalls of the semiconductor stack
Implementation Method 2
Optical structures respectively are over the first micro LED chip, the second micro LED chip and the third micro LED chip
Data Source
AI summary
A micro LED structure includes a first micro LED chip having opposite first and second sides, a second micro LED chip adjacent to the first side of the second micro LED chip, a third micro LED chip adjacent to the first side of the first micro LED chip, and optical structures respectively over the first micro LED chip, the second micro LED chip and the third micro LED chip. Each of the first, second and third micro LED chip includes a semiconductor stack, a metal pad and a reflective coating layer. The semiconductor stack includes a first semiconductor layer, an active layer in contact with the first semiconductor layer, and a second semiconductor layer in contact with the active layer. The metal pad is in contact with the first semiconductor layer, and the reflective coating layer is disposed around sidewalls of the semiconductor stack.