Electro-optical device, driving method thereof, and electronic apparatus with adjustable ratio between positive and negative field using black display voltage
A method of driving an electro-optical device having scanning lines, data lines, a switching transistor and a pixel electrode. The device also has an electro-optical layer interposed between the pixel electrode and a counter electrode. The method includes: supplying a data signal alternate between a positive and a negative voltage to the pixel electrode. The positive voltage has a potential greater than a counter electrode potential applied to the counter electrode and the negative voltage is a potential lower than the counter electrode potential; setting the counter electrode potential to reduce a flicker; supplying a first voltage that is either the positive or negative voltage to the pixel electrode in a first period; the other voltage to the pixel electrode in a second period. A ratio of the first period to the second period is variable.
1. A method of driving an electro-optical device including a plurality of scanning lines, a plurality of data lines, a switching transistor and a pixel electrode which are provided at an intersection between one of the scanning lines and one of the data lines, a counter electrode opposite to the pixel electrode, and an electro-optical layer interposed between the pixel electrode and the counter electrode, the method comprising:
supplying a data signal alternately having a positive voltage and a negative voltage to the pixel electrode through the one of the data line provided that the positive voltage is of a potential greater than a counter electrode potential applied to the counter electrode and that the negative voltage is of a potential lower than the counter electrode potential;
setting the counter electrode potential to reduce a flicker;
in a predetermined period which comprises a first period and a second period, supplying a first voltage that is one of the positive voltage and the negative voltage to the pixel electrode in the first period; and
supplying a second voltage that is the other of the positive voltage and the negative voltage to the pixel electrode in the second period; wherein
a ratio of a length of the first period to a length of the second period is variable in the predetermined period, the ratio of the length of the first period to the length of the second period is varied after the counter electrode potential has been set to reduce the flicker,
the predetermined period corresponds to one frame,
the one frame comprises a first field and a second field,
the first field corresponds to the first period,
the second field corresponds to the second period, and
in one of the first field and the second field, a ratio of a period length of the first field to a period length of the second field in the one frame is adjusted by supplying a third voltage as the data signal to the data line during a third period.
2. The method of driving the electro-optical device according to claim 1 , wherein
the third voltage is a voltage corresponding to a black display.
3. The method of driving the electro-optical device according to claim 1 , wherein
provided that N scanning lines are provided, a first scanning line group is set from a first scanning line to an Mth scanning line, and a second scanning line group is set from an (M+1)th scanning line to an Nth scanning line, any one scanning line of the first scanning line group and any one scanning line of the second scanning line group are alternately selected over the one frame,
in the first field, the first voltage is applied to a pixel electrode corresponding to a scanning line that belongs to the first scanning line group and the second voltage is applied to a pixel electrode corresponding to a scanning line that belongs to the second scanning line group, and
in the second field, the second voltage is applied to the pixel electrode corresponding to the scanning line that belongs to the first scanning line group and the first voltage is applied to the pixel electrode corresponding to the scanning line that belongs to the second scanning line group.
4. The method of driving the electro-optical device according to claim 1 , wherein
the predetermined period corresponds to a plurality of frames which comprises two or more successive frames, and
a ratio of a period length applied with the positive voltage to a period length applied with the negative voltage is changed in the predetermined period.
5. An electro-optical device comprising:
a plurality of scanning lines;
a plurality of data lines;
a switching transistor and a pixel electrode which are provided at an intersection between one of the scanning lines and one of the data lines;
a counter electrode opposite to the pixel electrode; and
an electro-optical layer interposed between the pixel electrode and the counter electrode, wherein
a data signal alternately having a positive voltage and a negative voltage is supplied to the pixel electrode through the one of the data line provided that the positive voltage is of a potential greater than a counter electrode potential applied to the counter electrode and the that the negative voltage is of a potential lower than the counter electrode potential,
the counter electrode is supplied with a counter electrode potential set to reduce a flicker,
in a predetermined period which comprises a first period and a second period, a first voltage that is one of the positive voltage and the negative voltage is supplied to the pixel electrode in the first period, and
a second voltage that is the other of the positive voltage and the negative voltage is supplied to the pixel electrode in the second period, and
the electro-optical device further comprising a control circuit adjusting a ratio of a length of the first period to a length of the second period in the predetermined period, the ratio of the length of the first period to the length of the second period is adjusted after the counter electrode potential has been set to reduce the flicker,
the predetermined period corresponds to one frame, the one frame comprises a first field and a second field, the first field corresponds to the first period, and the second field corresponds to the second period, and
a ratio of a period length of the first field to a period length of the second field in the one frame is adjusted by supplying a third voltage as the data signal to the data line during at least one clock cycle.
6. An electronic apparatus comprising the electro-optical device according to claim 5 .
7. The method of driving an electro-optical device according to claim 1 , further comprising:
setting the counter electrode potential to reduce the flicker by applying a constant correction voltage during the predetermined period.
8. The method of driving the electro-optical device according to claim 1 , wherein
the predetermined period corresponds to one frame, the one frame comprises a first field and a second field, the first field corresponds to the first period, and the second field corresponds to the second period, and
a ratio of a period length of the first field to a period length of the second field in the one frame is adjusted by supplying a third voltage as the data signal to the data line during at least one clock cycle.
9. The electro-optical device according to claim 5 , wherein
the predetermined period corresponds to one frame, the one frame comprises a first field and a second field, the first field corresponds to the first period, and the second field corresponds to the second period, and
in one of the first field and the second field, a ratio of a period length of the first field to a period length of the second field in the one frame is adjusted by supplying a third voltage as the data signal to the data line during a third period.
10. A method of driving an electro-optical device including a plurality of scanning lines, a plurality of data lines, a switching transistor and a pixel electrode which are provided at an intersection between one of the scanning lines and one of the data lines, a counter electrode opposite to the pixel electrode, and an electro-optical layer interposed between the pixel electrode and the counter electrode, the method comprising:
supplying a data signal alternately having a positive voltage and a negative voltage to the pixel electrode through the one of the data line provided that the positive voltage is of a potential greater than a counter electrode potential applied to the counter electrode and that the negative voltage is of a potential lower than the counter electrode potential;
setting the counter electrode potential to reduce a flicker;
in a predetermined period which comprises a first period and a second period, supplying a first voltage that is one of the positive voltage and the negative voltage to the pixel electrode in the first period; and
supplying a second voltage that is the other of the positive voltage and the negative voltage to the pixel electrode in the second period; wherein
a ratio of a length of the first period to a length of the second period is variable in the predetermined period, the ratio of the length of the first period to the length of the second period is varied after the counter electrode potential has been set to reduce the flicker,
the predetermined period corresponds to one frame, the one frame comprises a first field and a second field, the first field corresponds to the first period, and the second field corresponds to the second period, and
a ratio of a period length of the first field to a period length of the second field in the one frame is adjusted by supplying a third voltage as the data signal to the data line during at least one clock cycle.
11. The method of driving the electro-optical device according to claim 10 , wherein
the predetermined period corresponds to one frame,
the one frame comprises a first field and a second field,
the first field corresponds to the first period, and
the second field corresponds to the second period.
12. The method of driving the electro-optical device according to claim 11 , wherein
in one of the first field and the second field, a ratio of a period length of the first field to a period length of the second field in the one frame is adjusted by supplying a third voltage as the data signal to the data line during a third period.
13. The method of driving the electro-optical device according to claim 12 , wherein
the third voltage is a voltage corresponding to a black display.
14. The method of driving the electro-optical device according to claim 10 , wherein
provided that N scanning lines are provided, a first scanning line group is set from a first scanning line to an Mth scanning line, and a second scanning line group is set from an (M+1)th scanning line to an Nth scanning line, any one scanning line of the first scanning line group and any one scanning line of the second scanning line group are alternately selected over the one frame,
in the first field, the first voltage is applied to a pixel electrode corresponding to a scanning line that belongs to the first scanning line group and the second voltage is applied to a pixel electrode corresponding to a scanning line that belongs to the second scanning line group, and
in the second field, the second voltage is applied to the pixel electrode corresponding to the scanning line that belongs to the first scanning line group and the first voltage is applied to the pixel electrode corresponding to the scanning line that belongs to the second scanning line group.
15. The method of driving the electro-optical device according to claim 10 , wherein
the predetermined period corresponds to a plurality of frames which comprises two or more successive frames, and
a ratio of a period length applied with the positive voltage to a period length applied with the negative voltage is changed in the predetermined period.