Light Emitting Element Alignment Using Asymmetric AC Fields
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Solution Overview
Problem
Existing display devices face challenges in accurately aligning light emitting elements, which affects the efficiency and durability of the display, particularly in high-temperature environments.
Innovation Solution
A method of aligning light emitting elements by applying a ground voltage to a first electrode and a first AC voltage with an asymmetric waveform to a second electrode, followed by applying a second AC voltage with a symmetric waveform to the second electrode, creating asymmetric and symmetric electric fields to accurately position the light emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a symmetric AC voltage is applied to align light emitting elements, then the elements can be positioned in the center of electrodes, but the alignment accuracy is insufficient for high-precision display requirements
Solution Approach 1:
The alignment process is segmented into multiple stages: first applying a symmetric AC voltage to achieve rough center positioning, then switching to an asymmetric AC voltage for fine-tuned precision alignment. This segmentation allows each stage to optimize for its specific alignment requirement, achieving high overall precision without excessive complexity in a single step.
Solution Approach 2:
The patent employs dynamic voltage waveform switching during the alignment process. The system transitions from a symmetric waveform (sinusoidal or triangular) to an asymmetric waveform (sawtooth or ramp) based on the alignment stage, enabling adaptive control that achieves both initial positioning and final precision alignment through temporal variation in voltage characteristics.
2Ease of manufacture
If organic material is used as fluorescent material in OLED, then the manufacturing process is simple, but the material is vulnerable to high-temperature environments and has lower blue light efficiency
Solution Approach 1:
The patent changes the material parameter from organic fluorescent material to inorganic semiconductor fluorescent material. This parameter change fundamentally improves high-temperature durability and blue light efficiency while maintaining manufacturing feasibility through established semiconductor fabrication processes, resolving the contradiction between ease of manufacture and reliability in high-temperature environments.
3Reliability
If inorganic light emitting diode is used, then durability in high-temperature environments and blue light efficiency are improved, but alignment accuracy of light emitting elements becomes more critical
Solution Approach 1:
The patent applies preliminary alignment actions using symmetric AC voltage to position light emitting elements at the center of electrodes before final connection. This preliminary positioning ensures that even with stringent alignment requirements for inorganic LEDs, the elements are pre-positioned accurately, reducing the tolerance burden on subsequent fabrication steps and enabling reliable high-precision alignment.
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 method enhances the accuracy of light emitting element alignment, improving the efficiency and durability of display devices, especially in high-temperature environments, by ensuring proper electrical connections and emission characteristics.
Implementation Method 1
In case that a ground voltage is applied to the first electrode and a first AC voltage is applied to the second electrode spaced apart from the first electrode, an electric field formed by the first electrode and the second electrode may be an asymmetric electric field in which any one of positive polarity and negative polarity is dominant.
Implementation Method 2
In case that a ground voltage is applied to the first electrode and a second AC voltage is applied to the second electrode, an electric field formed by the first electrode and the second electrode may be a symmetric electric field.
Data Source
AI summary
A method of aligning light emitting elements includes applying a ground voltage to a first electrode and applying a first AC voltage to a second electrode spaced apart from the first electrode; and applying a ground voltage to the first electrode and applying a second AC voltage to the second electrode, wherein the first AC voltage has an asymmetric waveform.