Micro-LED Display Shutter Layer for High-Yield Manufacturing
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Solution Overview
Problem
The mass transfer of micro-LEDs from semiconductor wafers to glass substrates in micro-LED displays faces challenges such as high complexity, long transfer times, and alignment precision issues, which hinder high-yield manufacturing, especially for large displays like 4K resolutions.
Innovation Solution
A micro-electromechanical system (MEMS) shutter layer is introduced between the micro-LEDs and the color change layer, allowing individual control of shutter structures to open and close, reducing the need for precise alignment and increasing efficiency by using a single blue micro-LED to produce RGB colors through color conversion, and utilizing a cholesteric liquid crystal (CLC) or MEMS shutter technology for light control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional mass transfer methods are used for micro-LEDs from semiconductor wafers to glass substrates, then manufacturing complexity and transfer time increase, but manufacturing precision and yield remain insufficient
Solution Approach 1:
The patent introduces a transfer substrate as an intermediary carrier between the semiconductor wafer and the final glass substrate. Micro-LEDs are first transferred to the transfer substrate in high-density arrays, then subsequently transferred to the glass substrate. This two-stage transfer process simplifies each individual transfer step and enables high-yield manufacturing by decoupling the complex tasks of high-density placement and final substrate integration.
2Manufacturing precision
If precise alignment is required for micro-LED placement, then manufacturing time increases, but alignment precision must be maintained
Solution Approach 1:
The patent performs preliminary alignment and placement of micro-LEDs on the transfer substrate before final transfer to the glass substrate. Alignment marks and positioning structures are established in advance on the transfer substrate, enabling high-precision placement without requiring complex real-time alignment during the final transfer step. This preliminary preparation significantly reduces the time-critical alignment operations.
3Reliability
If multiple micro-LEDs are used per pixel for RGB colors, then color accuracy improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges multiple micro-LED elements into high-density arrays on the transfer substrate, where each pixel location can receive multiple micro-LEDs of different colors (red, green, blue). By combining color information from multiple micro-LEDs at each pixel location, the system achieves accurate color reproduction while maintaining a unified transfer process. This merging approach simplifies manufacturing compared to individually placing and aligning separate RGB sub-pixel structures.
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 significantly reduces the complexity and time required for micro-LED placement, enhances manufacturing efficiency, and improves light emission efficiency by allowing for precise color control and reduced micro-LED count, thereby addressing the bottlenecks in high-volume production of micro-LED displays.
Implementation Method 1
The shutter layer is formed by a cholesteric liquid crystal (CLC) layer, and for each of the sub-pixels, the CLC layer is configured to switch between a reflective state as the first state and a transparent state as the second state.
Implementation Method 2
each of the shutter structures is a micro-electromechanical system (MEMS) shutter structure comprising: a shielding layer having a plurality of openings aligned to the corresponding one of the sub-pixels to expose a corresponding one of the color change structures; and a micro-shutter corresponding to the openings, wherein the micro-shutter is movable between a first position and a second position relative to the shielding layer
Implementation Method 3
at least one electrostatic actuator configured to drive the shutter to move between the first position and the second position
Implementation Method 4
a spring structure supporting the shutter to move between the first position and the second position... the spring structure is deformed to generate an elastic force against the shutter... the elastic force generated by the spring structure drives the shutter to move from the second position back to the first position
Implementation Method 5
each of the color change structures corresponding to the first color sub-pixel comprises a first color converter configured to convert blue light emitted by the blue LED to a first color light, and each of the color change structures corresponding to the second color sub-pixel comprises a second color converter configured to convert blue light emitted by the blue LED to a second color light
Data Source
AI summary
A light emitting diode (LED) display panel includes a LED array, a color change layer, and a shutter layer disposed therebetween. The LED array is formed by multiple LEDs, defining multiple pixels. Each pixel has a corresponding LED and multiple sub-pixels. The color change layer includes multiple color change structures corresponding to the sub-pixels. The shutter layer defines multiple shutter structures correspondingly aligned to the sub-pixels and the color change structures. Each shutter structure is independently controlled to be switchable between a first state, where light emitted by the corresponding LED is prevented from reaching the corresponding color change structure, and a second state, where light emitted by the corresponding LED is allowed to reach the corresponding color change structure. For each pixel, only the shutter structure corresponding to one sub-pixel is in the second state, and the shutter structures corresponding to the other sub-pixels are in the first state.