Stacked Micro LED Module With Asymmetric Polarity Layout
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Solution Overview
Problem
Micro LEDs in stacked structures for micro LED displays face challenges in manufacturing due to complex electrical connections and low performance and reliability, making it difficult to transfer and protect these small LEDs without optical distortion or luminance loss.
Innovation Solution
A novel light emitting device structure with a circuit board, LED stacks generating different wavelengths, and a molding layer, featuring asymmetric semiconductor layer polarities, varying semiconductor layer thicknesses, and unique electrical connections to enhance performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If micro LEDs are arranged in stacked structure to simplify mounting, then mounting process is simplified, but electrical connection structure becomes complicated and manufacturing difficulty increases
Solution Approach 1:
The patent applies asymmetry by configuring the stacked LED structure with specific asymmetric electrical connection arrangements. The first and third LED stacks have asymmetric polarities with respect to the second LED stack, creating an optimized electrical connection structure that reduces complexity while maintaining the stacked configuration benefits for simplified mounting.
2Manufacturing precision
If micro LEDs are made smaller to increase pixel density, then display resolution is improved, but transfer difficulty and protection requirements increase
Solution Approach 1:
The patent merges multiple functions into the stacked LED structure. By vertically stacking multiple LED stacks (first, second, and third LED stacks with different wavelengths) within a single pixel unit, the structure achieves high pixel density while the integrated design facilitates unified transfer and protection processes, reducing the difficulties associated with handling individual tiny LEDs.
3Ease of manufacture
If stacked LED structure is used to reduce mounting complexity, then mounting is easier, but performance and reliability decrease
Solution Approach 1:
The patent applies local quality by optimizing specific regions of the stacked LED structure. Different semiconductor layers (first and second conductivity types) are strategically positioned with varying thicknesses and impurity concentrations at different locations within the stack. This localized optimization maintains high performance and reliability in each region while preserving the overall stacked configuration that simplifies mounting.
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 proposed structure improves the manufacturing process and reliability of micro LED displays by simplifying mounting and reducing optical distortion, while maintaining luminance and electrical connectivity.
Implementation Method 1
a first LED stack generating light of a first wavelength; a second LED stack disposed on the first LED stack and generating light of a second wavelength; and a third LED stack disposed on the second LED stack and generating light of a third wavelength
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A display module according to an embodiment includes: a circuit board; a light emitting device disposed on the circuit board; and a molding layer covering the light emitting device, the light emitting device, including: a first LED stack generating light of a first wavelength; a second LED stack disposed on the first LED stack and generating light of a second wavelength; and a third LED stack disposed on the second LED stack and generating light of a third wavelength, in which each of the first, second, and third LED stacks includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, and polarities of the first LED stack and the third LED stack disposed over and under the second LED stack are asymmetric with respect to the second LED stack.