Source driver, electro-optical device, projection-type display device, and electronic instrument
View Patent ↗A source driver includes P grayscale signal lines, a corresponding grayscale voltage being supplied to each of the P grayscale signal lines, Q switch signal lines, a corresponding grayscale voltage being supplied to each of the Q switch signal lines, a first DAC that outputs a grayscale voltage among P grayscale voltages supplied to the P grayscale signal lines based on grayscale data, a second DAC that outputs a grayscale voltage among Q grayscale voltages supplied to the Q switch signal lines based on the grayscale data, and a source line driver section that drives a source line based on an output from the first DAC or the second DAC. The source line driver section generates a second drive signal of the source line based on the output from the second DAC, and then generates a first drive signal of the source line based on the output from the first DAC within one horizontal scan period.
1. A source driver that drives a source line of an electro-optical device based on grayscale data, the source driver comprising:
P grayscale signal lines, P being a positive integer equal to or larger than two, a corresponding grayscale voltage being supplied to each of the P grayscale signal lines;
Q switch signal lines, Q being a positive integer equal to or smaller than P, a corresponding grayscale voltage being supplied to each of the Q switch signal lines;
a first DAC that outputs a grayscale voltage among P grayscale voltages that are supplied to the P grayscale signal lines based on the grayscale data;
a second DAC that outputs a grayscale voltage among Q grayscale voltages that are supplied to the Q switch signal lines based on the grayscale data; and
a source line driver section that drives the source line based on an output from the first DAC or the second DAC,
the source line driver section generating a second drive signal of the source line based on the output from the second DAC, and then generating a first drive signal of the source line based on the output from the first DAC within one horizontal scan period.
2. The source driver as defined in claim 1 , further comprising:
a switch voltage select circuit that outputs the Q grayscale voltages among at least (Q+1) grayscale voltages based on a polarity of a voltage applied to an electro-optical substance, a voltage of the source line being applied to the electro-optical substance.
3. The source driver as defined in claim 2 ,
the polarity being a polarity of a voltage applied to the electro-optical substance that is sealed between a pixel electrode that is provided with the voltage of the source line and a common electrode that is provided opposite to the pixel electrode.
4. The source driver as defined in claim 2 ,
when the switch voltage select circuit outputs the Q grayscale voltages from the (Q+1) grayscale voltages, the switch voltage select circuit outputting the Q grayscale voltages among the (Q+1) grayscale voltages excluding a grayscale voltage at the lowest potential when the polarity is positive.
5. The source driver as defined in claim 2 ,
when the switch voltage select circuit outputs the Q grayscale voltages from the (Q+1) grayscale voltages, the switch voltage select circuit outputting the Q grayscale voltages among the (Q+1) grayscale voltages excluding a grayscale voltage at the highest potential when the polarity is negative.
6. The source driver as defined in claim 1 ,
the source line driver section including an output buffer that drives the source line based on the output from the first DAC or the second DAC; and
the source line driver section driving the source line using the output buffer in a buffer output period within the one the horizontal scan period, and supplying an input voltage of the output buffer to the source line in a DAC output period after the buffer output period.
7. The source driver as defined in claim 6 ,
the buffer output period overlapping a period when the source line driver section drives the source line based on the output from the second DAC.
8. The source driver as defined in claim 6 ,
the DAC output period starts after a start timing of a period when the source line driver section drives the source line based on the output from the first DAC.
9. The source driver as defined in claim 1 ,
when impedance of a switch signal line among the Q switch signal lines in a period t B when the source line driver circuit drives the source line based on the output from the second DAC is referred to as Z B , and the impedance of a grayscale signal line among the P grayscale signal lines in a period t A when the source line driver circuit drives the source line based on the output from the first DAC is referred to as Z A , t A /t B being equal to Z A /Z B .
10. The source driver as defined in claim 1 ,
P being 2 K , K being an integer equal to or larger than two, and Q being 2 K-L , L being a natural number smaller than K.
11. The source driver as defined in claim 1 , further comprising:
a grayscale voltage generation circuit that generates a plurality of grayscale voltages, the plurality of grayscale voltages being obtained by dividing a voltage between given two voltages using resistors,
a corresponding grayscale voltage among the plurality of grayscale voltages that are generated by the grayscale voltage generation circuit being supplied to each of the P grayscale signal lines; and
at least one of the Q switch signal lines being driven by a buffer circuit.
12. An electro-optical device comprising the source driver as defined in claim 1 .
13. A projection-type display device comprising the source driver as defined in claim 1 .
14. An electronic instrument comprising the source driver as defined in claim 1 .
15. A source driver that drives a source line of an electro-optical device based on grayscale data, the source driver comprising:
P grayscale signal lines, P being a positive integer equal to or larger than two, a corresponding grayscale signal being supplied to each of the P grayscale signal lines;
Q switch signal lines, Q being a positive integer equal to or smaller than P, a corresponding grayscale signal being supplied to each of the Q switch signal lines;
a first DAC that outputs a grayscale signal among the P grayscale signals supplied to the P grayscale signal lines based on the grayscale data;
a second DAC that outputs a grayscale signal among the Q grayscale signals supplied to the Q switch signal lines based on the grayscale data; and
a source line driver section that drives the source line based on an output from the first DAC or the second DAC,
the source line driver section generating a second drive signal of the source line based on the output from the second DAC, and then generating a first drive signal of the source line based on the output from the first DAC within one horizontal scan period.
16. The source driver as defined in claim 15 , further comprising:
a switch signal select circuit that outputs the Q grayscale signals among at least (Q+1) grayscale signals based on a polarity of a signal applied to an electro-optical substance, a signal of the source line being applied to the electro-optical substance.
17. An electro-optical device comprising the source driver as defined in claim 15 .
18. A projection-type display device comprising the source driver as defined in claim 15 .
19. An electronic instrument comprising the source driver as defined in claim 15 .