Method of aligning light emitting elements and method of manufacturing display device using the same
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.
1. A method of aligning light emitting elements, comprising:
applying a ground voltage to a first electrode and applying a first alternating current (AC) voltage to a second electrode spaced apart from the first electrode, the first AC voltage having an asymmetric waveform;
applying a ground voltage to the first electrode and applying a second AC voltage to the second electrode, the second AC voltage having a symmetric waveform; and
aligning light emitting elements between the first electrode and the second electrode, wherein
in response to a ground voltage being applied to the first electrode and a first AC voltage being applied to the second electrode spaced apart from the first electrode, an electric field formed by the first electrode and the second electrode is an asymmetric electric field in which any one of positive polarity and negative polarity is dominant.
2. The method of claim 1 , wherein a voltage waveform of a positive polarity region of the first AC voltage and a voltage waveform of a negative polarity region of the first AC voltage are left-right asymmetric.
3. The method of claim 1 , wherein the first AC voltage has a sawtooth waveform or a ramp waveform.
4. The method of claim 1 , wherein a voltage waveform of a positive polarity region of the second AC voltage and a voltage waveform of a negative polarity region of the second AC voltage are left-right symmetric.
5. The method of claim 1 , wherein the second AC voltage has a sinusoidal waveform, a spherical waveform, or a triangular waveform.
6. The method of claim 1 , wherein a driving frequency of the first AC voltage is lower than a driving frequency of the second AC voltage.
7. The method of claim 6 , wherein the first AC voltage has a driving frequency of about 1 Hz to about 1 kHz.
8. The method of claim 6 , wherein the second AC voltage has a driving frequency of about 1 kHz to about 100 kHz.
9. A method of manufacturing a display device, comprising:
forming partition wall, a first electrode, and a second electrode on a substrate;
applying a coating solution containing light emitting elements onto sub-pixels;
forming an electric field between the first electrode and the second electrode to align the light emitting elements;
removing the coating solution;
forming first connection electrodes electrically connecting the first electrode to an end of each of the light emitting elements; and
forming second connection electrodes electrically connecting the second electrode to another end of each of the light emitting elements,
wherein the forming of the electric field between the first electrode and the second electrode to align the light emitting elements include:
applying a ground voltage to the first electrode; and applying a first alternating current (AC) voltage having an asymmetric waveform to the second electrode; and
applying a ground voltage to the first electrode and applying a second AC voltage to the second electrode, wherein
in response to applying a ground voltage to the first electrode and applying a first AC voltage to the second electrode spaced apart from the first electrode, an electric field formed by the first electrode and the second electrode is an asymmetric electric field in which any one of positive polarity and negative polarity is dominant.
10. The method of claim 9 , wherein in case that a ground voltage is applied to the first electrode and a first AC voltage is applied to the second electrode, the light emitting elements are disposed toward the first electrode.
11. The method of claim 9 , wherein
each of the light emitting elements includes:
a first conductive semiconductor disposed at the another end of each of the light emitting elements; and
a second conductive semiconductor disposed at the end of each of the light emitting elements,
the first conductive semiconductor is disposed adjacent to the second electrode, and
the second conductive semiconductor is disposed adjacent to the first electrode.
12. The method of claim 11 , wherein
the first conductive semiconductor is an n-type semiconductor layer, and
the second conductive semiconductor is a p-type semiconductor layer.
13. The method of claim 9 , wherein in case that a ground voltage is applied to the first electrode and a second AC voltage is applied to the second electrode, the light emitting elements are aligned at a center between the first electrode and the second electrode.
14. The method of claim 9 , wherein the second AC voltage has a symmetric waveform.
15. The method of claim 9 , wherein a driving frequency of the first AC voltage is lower than a driving frequency of the second AC voltage.
16. The method of claim 9 , further comprising:
electrically disconnecting the first electrode after the forming of the second connection electrodes to form a first electrode for each of the sub-pixels.
17. The method of claim 9 , wherein the removing of the coating solution includes volatilizing the coating solution.