Method and apparatus for driving ferroelectric LCD and aligning method under electric field applied thereto
View Patent ↗A method of aligning Half V-Switching Mode ferroelectric liquid crystal material in the presence of an applied electric field, a driving method, and an apparatus for driving a ferroelectric liquid crystal display using the same has a high response speed characteristics and a wide viewing angle characteristics. The liquid crystal material has a small capacitance, C, and is driven according to a double frequency column inversion driving method operating at about 120 Hz to display a picture.
1. A method of aligning ferroelectric liquid crystal material within a liquid crystal display, comprising:
providing a liquid crystal display (LCD) panel having a plurality of liquid crystal cells arranged in a matrix pattern;
providing ferroelectric liquid crystal (FLC) material within the plurality of liquid crystal cells at a first temperature;
cooling the FLC material below a phase transformation temperature sufficient to cause the FLC material to exhibit a smectic C phase; and
applying an electric field to the LCD panel to align the FLC material during the cooling,
wherein the applied electric field has a alignment polarity pattern wherein a polarity of the applied electric field is inverted between adjacent vertical lines of the liquid crystal cells.
2. The aligning method according to claim 1 , wherein providing the FLC material includes injecting the FLC material.
3. The aligning method according to claim 1 , wherein providing the FLC material includes dispensing the FLC material.
4. The aligning method according to claim 1 , wherein the FLC material exhibits an isotropic phase at the first temperature.
5. The aligning method according to claim 1 , wherein the FLC material exhibits a nematic phase at the first temperature.
6. The aligning method according to claim 1 , wherein the phase transformation temperature is about 60° C. to about 80° C.
7. The aligning method according to claim 1 , wherein the applying the electric field includes applying a voltage of about ±1-9V to the LCD panel.
8. The aligning method according to claim 1 , wherein light is transmittable by liquid crystal cells containing the aligned FLC material in the presence of an applied electric field having a driving polarity pattern opposite the alignment polarity pattern.
9. A method of driving a ferroelectric liquid crystal display panel, comprising:
applying a first driving data voltage having a first polarity pattern to liquid crystal cells within a liquid crystal display (LCD) panel containing aligned ferroelectric liquid crystal (FLC) material during a first sub-frame period of the LCD panel, less than a frame period of the LCD panel, wherein the aligned FLC material is aligned in the presence of an applied electric field having an alignment polarity pattern wherein a polarity of the applied electric field is inverted between adjacent vertical lines of liquid crystal cells while cooling the FLC material below a phase transformation from a nematic phase to a smectic C phase; and
applying a second driving data voltage having a second polarity pattern to the liquid crystal cells containing the aligned FLC material during a second sub-frame period of the frame period of the LCD panel, wherein the second polarity pattern is opposite the first polarity pattern, and wherein the second sub-frame period is substantially equal to a remainder of time within the frame period after the first sub-frame period.
10. The driving method according to claim 9 , wherein polarities of driving data voltages having the first and second polarity patterns, provided to consecutively arranged ones of adjacent vertical lines of the LCD panel, are opposite each other.
11. The driving method according to claim 10 , wherein the polarity of the driving data voltages applied to each of the liquid crystal cells is inverted between successive sub-periods.
12. The driving method according to claim 9 , further comprising applying a scan signal to the LCD panel to select a horizontal line of liquid crystal cells to which the first and second driving data voltages are applied.
13. The driving method according to claim 9 , wherein
the first polarity pattern is substantially identical to the alignment polarity pattern;
the second polarity pattern is opposite from the alignment polarity pattern; and
within each frame period of the LCD panel, the first sub-frame period occurs prior to the second sub-frame period.
14. The driving method according to claim 9 , wherein light is transmittable by liquid crystal cells containing the aligned FLC material in the presence of an applied electric field having a driving polarity pattern opposite the alignment polarity pattern.