Stacked LED Subpixel Structure for Bright High-Density Displays
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Solution Overview
Problem
Conventional LEDs require a large area for each subpixel, leading to increased manufacturing complexity and potential deterioration in brightness and luminous efficiency due to heat generation.
Innovation Solution
A light emitting device with a stacked structure comprising multiple LED stacks, each emitting a different color, is used to increase the area of each subpixel without increasing the pixel area, while also improving current distribution, heat dissipation, and light efficiency through a mesh structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If subpixels are arranged on a two-dimensional plane with one LED chip per subpixel, then each subpixel can be formed with a simple structure, but the number of LED chips required exceeds millions causing excessive mounting time and manufacturing complexity
Solution Approach 1:
The invention divides a single pixel into multiple subpixels (blue, green, red) that are arranged in a stacked three-dimensional configuration rather than a two-dimensional plane. This segmentation allows multiple color-emitting regions to occupy vertical space, reducing the total number of LED chips required and decreasing mounting time while maintaining full color capability.
Solution Approach 2:
The patent transitions from a two-dimensional arrangement of subpixels to a three-dimensional stacked structure. By utilizing the vertical dimension, multiple subpixels are stacked one above another, which reduces the horizontal area required and decreases the total number of mounting positions, thereby improving manufacturing productivity.
2Area of stationary object
If the area of each subpixel is reduced to fit more pixels in a limited area, then the display resolution increases, but brightness deteriorates due to reduced luminous area and heat generation increases
Solution Approach 1:
By stacking subpixels vertically in the third dimension, the patent allows each subpixel to maintain a larger luminous area within a compact pixel footprint. The vertical arrangement enables sufficient light emission area for each color while keeping the overall pixel area small, thus maintaining brightness without sacrificing resolution.
3Area of stationary object
If the area of each subpixel is reduced, then more pixels can be packed in a limited display area, but luminous efficiency deteriorates due to heat generated in the LED chip
Solution Approach 1:
The invention segments the pixel structure into multiple vertically-stacked subpixels, each with adequate luminous area. This segmentation allows heat to be distributed across multiple discrete LED chips rather than concentrated in a single small chip, improving heat dissipation and maintaining luminous efficiency while achieving high pixel density.
4Ease of operation
If multiple LED chips are arranged in a two-dimensional plane to form subpixels, then each subpixel can be independently controlled, but the manufacturing complexity increases due to the large number of chips requiring mounting
Solution Approach 1:
The patent employs a three-dimensional stacked architecture where subpixels are arranged vertically rather than horizontally. This dimensional change reduces the total number of mounting positions from millions to a manageable number, simplifying the mounting process while preserving independent control capability through separate electrical connections to each stacked subpixel.
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 solution allows for a larger subpixel area without increasing the pixel area, reduces manufacturing time, enhances current distribution, improves heat dissipation, and increases light efficiency.
Implementation Method 1
A light emitting diode (LED) has been widely used as an inorganic light source in various fields such as a display apparatus
Implementation Method 2
reducing the area of each subpixel would also cause deterioration in luminous efficiency of the LED from heat generated in an LED chip
Data Source
Figure 1~2A
Figure 2B~3B
Figure 4A~5A
AI summary
A light emitting device for a display includes a substrate and first, second, and third LED sub-units, a first transparent electrode between the first and second LED sub-units and in ohmic contact with the first LED sub-unit, a second transparent electrode between the second and third LED sub-units and in ohmic contact with the second LED sub-unit, a third transparent electrode between the second transparent electrode and the third LED sub-unit and in ohmic contact with the third LED sub-unit, at least one current spreader connected to at least one of the first, second, and third LED sub-units, electrode pads disposed on the substrate, and through-hole vias formed through the substrate, in which at least one of the through-hole vias is formed through the substrate and the first and second LED sub-units.