Data line driving circuit, electro-optical device, data line driving method, and electronic apparatus
View Patent ↗A data line driving circuit connected to data lines includes a bit shift unit that outputs input digital data composed of a plurality of bits for defining the brightness of pixels or bit-shifts the plurality of bits to lower levels to output them, based on a control signal, and a supply unit that supplies the output digital data of the bit shift unit to a D/A conversion unit. The D/A conversion unit supplies gray-scale signals obtained by D/A converting the output digital data of the supply unit to the data lines.
1. An electro-optical device comprising:
a plurality of data lines;
a plurality of scanning lines;
a plurality of pixel circuits that are arranged corresponding to intersections of the data lines and the scanning lines, each pixel circuit including:
an electro-optical element whose brightness is controlled by gray-scale signals supplied from the data lines;
a driving transistor that drives the electro-optical elements; and
a light-emission control transistor that controls a light-emission period of the electro-optical elements based on a light-emission control signal; and
a data line driving circuit connected to the data lines, the data line driving circuit including:
a D/A conversion circuit;
a bit shift circuit that switches, according to a control signal, whether input digital data constituted by a plurality of bits that regulate brightness of pixels is output as-is or whether the plurality of bits are bit-shifted to a lower side and are output;
a supply circuit that supplies output digital data of the bit shift circuit to the D/A conversion circuit; and
a pseudo-halftone processing circuit that is provided between the bit shift circuit and the supply circuit to perform pseudo-halftone processing that pseudo-increases the number of gray-scale levels of the output digital data of the bit shift circuit,
wherein the D/A conversion circuit supplies the gray-scale signals obtained by D/A converting the output digital data of the supply circuit to the data lines, and
when the input digital data is bit-shifted to a lower side by the bit shift circuit, a light-emission period of the electro-optical elements is adjusted by controlling the light-emission control signal.
2. The electro-optical device as set forth in claim 1 ,
wherein the pseudo-halftone processing circuit performs the pseudo-halftone processing on the output digital data of the bit shift circuit according to a dither method.
3. The electro-optical device as set forth in claim 1 ,
wherein the pseudo-halftone processing means performs the pseudo-halftone processing on the output digital data of the bit shift means according an error diffusion method.
4. The electro-optical device as set forth in claim 1 ,
wherein the data lines are constituted by a plurality of wiring lines,
the D/A conversion circuit is provided with a plurality of D/A conversion sub-circuits corresponding to the plurality of wiring lines, respectively, and
the supply circuit converts supplied digital data into a plurality of conversion data, respectively corresponding to the plurality of D/A conversion sub-circuits and outputs them to the D/A conversion circuit.
5. The electro-optical device as set forth in claim 4 ,
wherein each pixel circuit includes three pixel sub-circuits that display colors of R, G, and B, and
the input digital data is constituted by data indicating an R color gray-scale level, data indicating a G color gray-scale level, and data indicating a B color gray-scale level.
6. An electronic apparatus comprising the electro-optical device as set forth in claim 1 .