Micro LED Display Size and Optical Efficiency via CMOS Backplane
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Solution Overview
Problem
Current micro LED display technologies are limited in size due to wafer size constraints, requiring separate optical modules for displays larger than 1.2 inches, which increases module size and decreases optical efficiency, and lack flexibility for various applications such as wearable devices and medical devices.
Innovation Solution
A micro LED display device with a CMOS backplane and a method of fabricating it by flip-chip bonding micro LED pixels to a CMOS backplane, allowing for flexible arrangement and size adjustment by modifying the CMOS backplane structure and common electrode configuration, enabling displays of various sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a separate optical module is used for displays larger than 1.2 inches, then the display size can be increased, but the module size increases and optical efficiency decreases
Solution Approach 1:
The patent merges the micro LED array and the optical module into a single integrated structure. The optical module is positioned directly adjacent to the micro LED array, eliminating the need for separate optical components and reducing optical path losses. This integration allows displays of various sizes to be achieved without sacrificing optical efficiency, as the light travels a shorter distance and undergoes fewer reflections and refractions at interfaces between separate components.
2Adaptability or versatility
If the LED chip is transferred to a flexible substrate to give flexibility, then wearable and medical applications become possible, but the fabrication process becomes more complex
Solution Approach 1:
The patent segments the display device into two main parts: a rigid micro LED array fabricated on a standard substrate, and a flexible substrate that can be conformally attached to various surfaces. The micro LED array is fabricated using conventional semiconductor processes, while the flexible substrate is designed separately with appropriate mechanical properties. This segmentation allows the complex flexibility requirement to be isolated to a specific component, simplifying the overall fabrication process while still achieving wearable and medical application compatibility.
3Loss of energy
If the micro LED array is integrated with the optical module, then optical efficiency increases and module size can be reduced, but the fabrication process becomes more challenging
Solution Approach 1:
The patent positions the optical module in a plane adjacent to the micro LED array rather than stacking it vertically, utilizing the lateral dimension for integration. This planar integration approach maintains short optical paths for high efficiency while allowing independent fabrication of the micro LED array and optical components on separate substrates. The two components are then bonded together using conventional thin-film deposition and bonding techniques, avoiding the need for complex three-dimensional integration processes.
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
Enables the implementation of displays of various sizes by changing the CMOS backplane structure and common electrode configuration, overcoming size limitations and enhancing optical efficiency, and allowing for flexible integration in diverse applications.
Implementation Method 1
A light emitting diode (LED) is a sort of semiconductor device which converts electric energy to light energy.
Implementation Method 2
a light emitting diode (LED) display device, including: a micro LED panel in which a plurality of micro LED pixels is arranged
Data Source
AI summary
The present invention relates to a puzzle-type micro light emitting diode (LED) display device which is capable of implementing a display having various sizes, the micro LED display device including: a micro LED panel in which a plurality of micro LED pixels is arranged in rows and columns; and a micro LED driving substrate (backplane) configured to include an active matrix (AM) circuit unit including a plurality of CMOS cells corresponding to the plurality of micro LED pixels, and a control circuit unit disposed in an outer region of the AM circuit unit, in which the control circuit unit is disposed to be adjacent to two sides among four sides of the micro LED panel.