Vertical Micro LED Epitaxial Stack for Ultra-High-Resolution Displays
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Solution Overview
Problem
Current manufacturing techniques for high-resolution display apparatuses using micro LEDs face challenges in producing high-efficiency micro LED chips and efficient transfer technologies for arranging these chips in precise positions, limiting the resolution and efficiency of display devices.
Innovation Solution
A light emitting structure with a vertical stack epitaxial structure is developed, comprising a substrate with sequentially stacked epitaxial structures including semiconductor layers, carrier blocking layers, active layers, and junction layers, allowing for the formation of monolithic micro LED devices with different emission wavelengths, which are then arranged in a monolithic form on a growth substrate with varying mesa structures for efficient light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional micro LED manufacturing techniques are used, then display resolution can be improved, but manufacturing complexity and transfer technology requirements increase significantly
Solution Approach 1:
The patent transitions from planar lateral arrangement of micro LEDs to vertical stacking configuration. Multiple micro LED chips are stacked vertically along the light emission direction, with each chip having different emission wavelengths. This vertical dimensionality change enables high-resolution color display without requiring complex lateral transfer technology, as chips are stacked in the vertical direction rather than arranged horizontally.
Solution Approach 2:
The patent combines multiple micro LED chips with different emission wavelengths (red, green, blue) into a single vertical stack structure. These chips are electrically connected in parallel and optically combined to produce full-color light emission. This merging approach integrates multiple color channels into one compact vertical unit, simplifying the overall display structure and reducing transfer complexity.
2Adaptability or versatility
If multiple separate micro LED chips are arranged laterally, then color display is achieved, but the number of chips and transfer operations increase
Solution Approach 1:
Instead of arranging multiple micro LED chips laterally in a plane to achieve color display, the patent stacks them vertically in the light emission direction. This vertical arrangement reduces the lateral footprint and minimizes the number of chips required per pixel, as multiple wavelengths are combined in the vertical dimension rather than spread out horizontally.
Solution Approach 2:
The patent implements a nested structure where multiple micro LED chips are vertically nested within a single pixel structure. Each chip is stacked above the other, forming a compact vertical assembly that fits within a small lateral footprint. This nesting approach allows multiple color channels to be integrated into a single pixel location, reducing the total number of chips needed.
3Manufacturing precision
If advanced transfer technologies are used for precise chip arrangement, then positioning accuracy improves, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent shifts the positioning challenge from lateral precision to vertical alignment. By stacking chips vertically, the critical positioning requirement moves to the vertical dimension, which can be achieved through simpler bonding processes. This reduces the need for complex lateral transfer technologies while maintaining precise chip arrangement through vertical stacking techniques.
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 enables the creation of high-resolution display apparatuses with reduced manufacturing complexity and cost, eliminating the need for advanced transfer technologies and color conversion layers, while achieving ultra-high resolutions such as 5000 ppi or higher.
Implementation Method 1
Each of the first epitaxial structure, the second epitaxial structure, and the third epitaxial structure may be configured to emit light at different wavelengths
Data Source
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AI summary
A light emitting structure includes: a substrate; a first epitaxial structure disposed on the substrate; a second epitaxial structure disposed on the first epitaxial structure; and a third epitaxial structure disposed on the second epitaxial structure. Each of the first epitaxial structure, the second epitaxial structure, and the third epitaxial structure comprises, in a sequentially stacked structure, a first semiconductor layer of a first conductivity, a carrier blocking layer, an active layer, and a second semiconductor layer of a second conductivity.