Micro LED Transfer Device Using Liquid Crystal Light Valve
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Solution Overview
Problem
Existing micro light emitting diode (micro LED) transfer devices cannot selectively transfer massive micro LEDs, leading to yield improvement and cost reduction challenges due to complex fabrication and uncertainty in defect positions within the array.
Innovation Solution
A micro light emitting diode transfer device and method utilizing a liquid crystals light valve with sub light valves corresponding to micro LEDs on a transfer substrate, where light is filtered to selectively irradiate and detach micro LEDs from the transfer substrate, allowing them to adhere to a target substrate, aided by an adsorption member for transferring substandard LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a structural transfer head is used for mass transfer, then transfer speed is improved, but device complexity increases and selective transfer capability is lost
Solution Approach 1:
The transfer head is divided into multiple independently controllable light valves, each corresponding to a specific micro LED or group of micro LEDs. This segmentation allows selective activation of individual regions while maintaining the overall mass transfer capability, resolving the contradiction between transfer speed and selectivity.
Solution Approach 2:
The transfer head incorporates dynamically controllable light valves that can be selectively activated or deactivated based on real-time defect detection feedback. This dynamic control enables the system to switch between mass transfer mode (for good LEDs) and selective transfer mode (for defect-containing regions), maintaining high productivity while enabling selectivity when needed.
2Productivity
If a structural transfer head is used for mass transfer, then transfer efficiency is improved, but adaptability decreases
Solution Approach 1:
The transfer head is designed with multi-functional light valves that can operate in different modes: mass transfer mode for high efficiency, selective transfer mode for defect handling, and repair mode for replacing defective LEDs. This universal design allows a single device to perform multiple functions, resolving the contradiction between transfer efficiency and adaptability.
Solution Approach 2:
The system incorporates feedback from defect detection to control the light valve activation pattern. When defects are detected, the feedback signal triggers selective activation of corresponding light valves, enabling the system to adapt its transfer behavior based on actual LED quality, thus maintaining both efficiency and versatility.
3Reliability
If selective transfer of massive micro LEDs is implemented, then yield improvement is achieved, but device complexity increases
Solution Approach 1:
Light valves serve as intermediaries between the transfer head and micro LEDs, enabling selective energy transfer to specific regions. This intermediary mechanism allows complex selective transfer functionality to be achieved through a relatively simple optical component, reducing the overall device complexity while maintaining yield improvement capability.
Solution Approach 2:
The patent replaces complex mechanical selection mechanisms with optical control through light valves. Instead of using complex mechanical structures to physically select and transfer individual LEDs, the system uses light to selectively activate adhesion/release properties, simplifying the device while enabling selective transfer for yield improvement.
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 selective and efficient transfer of massive micro LEDs, improving production yield and repair efficiency while reducing production costs by precisely controlling light exposure through the liquid crystals light valve and adsorption mechanism.
Implementation Method 1
a liquid crystals light valve disposed on a transmission path of the planar light; the liquid crystals light valve comprises a plurality of sub light valves, and the sub light valves are corresponding to micro light emitting diodes on the transfer substrate
Implementation Method 2
The rapid and selective mass transfer can be achieved by a structural transfer head through intermolecular forces
Data Source
AI summary
The present disclosure provides a micro light emitting diode transfer device and a micro light emitting diode transfer method. The micro light emitting diode transfer device includes a holding member, a light source, and a liquid crystals light valve. The liquid crystals light valve is disposed on a transmission path of planar light and includes a plurality of sub light valves. The micro light emitting diodes of irradiated part can be separated from the transfer substrate and adhere to a target substrate, and thereby the micro light emitting diodes can be selectively transferred.