Micro-LED Subpixel Layout for Color Purity and Easy Replacement
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Solution Overview
Problem
Micro LEDs in display devices face challenges due to their small size, making mounting and replacing defective LEDs difficult, and varying light intensities across sub-pixels due to different current densities, leading to decreased efficiency and color purity.
Innovation Solution
A light emitting device comprising first, second, and third light emitting cells with varying areas and wavelength converters, each emitting different colors, and partition walls to optimize mounting and efficiency, with color filters to enhance color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If micro LEDs are made very small (less than 200 micrometers) to increase pixel density, then display resolution is improved, but mounting and replacement difficulty increases
Solution Approach 1:
The device is divided into modular light emitting cells with standardized pad structures, allowing individual cells to be handled and replaced as discrete units despite their small size. The segmentation of the LED structure into distinct functional regions (light emitting region, pad region, wavelength converter region) enables precise manipulation during mounting and replacement processes.
Solution Approach 2:
The pad structure serves as an intermediary element that facilitates the connection between the micro LED cell and the substrate. The pads provide standardized electrical and mechanical connection points, making it easier to mount and replace the tiny LED cells without requiring complex handling procedures.
2Measurement precision
If different current densities are applied to different sub-pixels to compensate for filter efficiency differences, then color purity is improved, but light emitting efficiency decreases
Solution Approach 1:
Different area sizes are assigned to different light emitting cells (first light emitting cell has a larger area than the third light emitting cell) to locally compensate for differences in wavelength converter efficiency. This allows each cell to operate at optimal current density while achieving uniform light output across different colors, eliminating the need to reduce overall efficiency to maintain color purity.
Solution Approach 2:
The area parameter of light emitting cells is changed to compensate for variations in wavelength converter performance. By adjusting the physical size of cells with less efficient wavelength converters, the system achieves uniform brightness without requiring inefficient current density adjustments, thus maintaining both color purity and light emitting efficiency.
3Measurement precision
If larger area light emitting cells are used to compensate for lower wavelength converter efficiency, then color uniformity is improved, but device area increases
Solution Approach 1:
Asymmetric area distribution among light emitting cells is implemented, where cells with less efficient wavelength converters have larger areas and cells with more efficient converters have smaller areas. This asymmetric design compensates for converter efficiency differences while maintaining overall compactness through optimized spatial arrangement.
Solution Approach 2:
The patent addresses area compensation by utilizing the two-dimensional plane efficiently through strategic positioning and arrangement of cells with different areas. Rather than simply increasing overall device area, the design optimizes the distribution of cell areas across the available space, compensating for wavelength converter efficiency differences while maintaining a compact form factor.
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
Facilitates easy mounting and replacement of LEDs, ensures optimal luminous efficiency, and achieves high color purity and reproducibility in display apparatus.
Implementation Method 1
a first wavelength converter configured to convert a wavelength of light emitted from the first light emitting cell into a first wavelength, and a second wavelength converter configured to convert a wavelength of light emitted from the second light emitting cell into a second wavelength
Data Source
AI summary
A display apparatus including a substrate, a first sub-pixel, a second sub-pixel, and a third sub-pixel disposed on the substrate and configured to emit red light, green light, and blue light, respectively, partition walls disposed between the first sub-pixel, the second sub-pixel, and the third sub-pixel, and configured to not transmit light, in which the first sub-pixel, the second sub-pixel, and the third sub-pixel include a first light emitting cell, a second light emitting cell, and a third light emitting cell, respectively, and a height of each of the first, second, and third light emitting cells is lower than a height of the partition walls, and a difference between the height of the partition walls and the height of each of the first, second, and third light emitting cells is less than 100 μm.