Light-Emitting Element Alignment Using Dual-Frequency AC Biasing
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Solution Overview
Problem
Existing methods for aligning light emitting elements on electrodes in display devices face challenges in achieving optimal orientation and alignment, which affects the efficiency and performance of the display devices.
Innovation Solution
A method involving the application of alternating current (AC) voltages with different frequencies to electrodes to align light emitting elements, utilizing the Clausius-Mossotti factor to orient conductive semiconductors, and employing asymmetrical waveforms to enhance alignment precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single frequency AC voltage is applied to align light emitting elements, then the alignment process is simple, but the biasing ratio and orientation precision are insufficient
Solution Approach 1:
The patent applies AC voltages with different frequencies sequentially to the electrodes. A first AC voltage at a first frequency is applied to initially align the light emitting elements, followed by a second AC voltage at a second frequency to further improve the biasing ratio. This periodic action with varying frequencies enables precise orientation control without requiring complex simultaneous multi-parameter control systems.
Solution Approach 2:
The patent changes the frequency parameter of the applied AC voltage between two distinct values (first frequency and second frequency). By switching between these frequency parameters, the system achieves different alignment effects that collectively improve the biasing ratio and orientation precision of the light emitting elements, resolving the contradiction between simplicity and precision.
2Manufacturing precision
If light emitting elements are aligned without frequency switching, then the process is fast, but the biasing ratio remains low
Solution Approach 1:
The method employs periodic application of AC voltages at different frequencies in sequence. The first AC voltage at the first frequency performs initial alignment, and the second AC voltage at the second frequency enhances the biasing ratio. This time-sequential periodic action achieves high precision alignment and improved biasing ratio without requiring complex simultaneous operations, thus minimizing time loss.
Solution Approach 2:
The first AC voltage application serves as a preliminary alignment step that prepares the light emitting elements for the subsequent second frequency treatment. This preliminary action ensures that elements are roughly oriented before the second frequency is applied to fine-tune the biasing ratio, making the overall process efficient and time-effective.
3Manufacturing precision
If asymmetric waveform is used for AC voltage, then alignment precision is improved, but waveform control complexity increases
Solution Approach 1:
The patent specifies that each AC voltage (at both first and second frequencies) has an asymmetric waveform. This asymmetry in the voltage waveform creates a directional bias that improves the orientation precision and biasing ratio of the light emitting elements during alignment, resolving the technical contradiction by accepting controlled waveform complexity for the sake of precision.
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
Improves the biasing ratio of light emitting elements, ensuring they are correctly oriented and aligned, thereby enhancing the performance and efficiency of the display device.
Implementation Method 1
applying a first alternating current (AC) voltage having a first frequency to the first electrode and the second electrode; and applying a second AC voltage having a second frequency different from the first frequency to the first electrode and the second electrode after applying the first AC voltage
Implementation Method 2
the first frequency may be a frequency in case that a real part of a Clausius-Mossotti (CM) factor is less than 0, and the CM factor is defined as where ε*p denotes a complex dielectric constant of any one of the plurality of light emitting elements, and ε*m denotes a complex dielectric constant of a solvent included in the ink
Data Source
AI summary
A method of aligning a light emitting element includes providing ink including light emitting elements on a substrate, a first electrode and a second electrode spaced apart from the first electrode being disposed on the substrate, applying a first alternating current (AC) voltage having a first frequency to the first electrode and the second electrode, and applying a second AC voltage having a second frequency different from the first frequency to the first electrode and the second electrode after applying the first AC voltage.