Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-09-13
2004-06-15
Liang, Regina (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S078000, C345S087000, C345S089000, C345S098000
Reexamination Certificate
active
06750840
ABSTRACT:
Japanese Patent Application No. 2000-277811, filed Sep. 13, 2000, is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electro-optical device, a method of driving the electro-optical device and an electronic instrument.
2. Description of Related Art
In an active matrix type TFT (Thin Film Transistor) liquid crystal device, for example, a data-line drive circuit converts RGB data to an analog signal which is in turn supplied to a plurality of data lines in the liquid crystal panel as data signal voltage. The individual pixels that correspond to selected scan lines are charged with the data signal voltage that is supplied to each of the data lines from the data-line drive circuit. The liquid crystal device selects a scan line from one that is, for example, closer to the data line drive circuit in one frame period. In this case, the closer to the end of the frame period, the farther the distance from the data-line drive circuit to a pixel to be charged becomes. This is more prominent as the liquid crystal screen gets larger.
Particularly, as the liquid crystal panel of the liquid crystal device becomes larger, the interconnection resistance and the interconnection capacitance become greater, thus increasing the influence of the interconnection delay on the supply of the data signal voltage to the data lines.
FIG. 21A
shows a simple T type or &pgr; type model of the interconnection delay. The model in
FIG. 21A
includes a power source
300
equivalent to the data-line drive circuit of a liquid crystal device, a line L equivalent to a data line and having parasitic resistances R
1
to R
3
and parasitic capacities C
1
to C
3
of the data line and pixels.
FIG. 31B
shows chronological changes in voltages charged in the capacitors C
1
to C
3
respectively connected to points P
1
to P
3
when a voltage is supplied to the line L from the power source
300
. As the capacitor C
1
at the point P
1
is located closest to the power source
300
, the capacitor C
1
is charged rapidly. The voltage of the capacitor C
1
can therefore reach a required voltage V
1
at time t
a
in a predetermined period from t
1
to t
2
. As the capacitor C
3
at the point P
3
is located farthest to the power source
300
, by way of contrast, the capacitor C
3
demonstrates a charge characteristic of a gentle slope. Therefore, the voltage of the capacitor C
3
cannot reach the required voltage V
1
in the predetermined period from t
1
to t
2
but reaches it only at time t
c
.
This model can be applied to a liquid crystal device so that the liquid crystal device according to the related art has to face such a problem that a selected pixel cannot be charged to a predetermined voltage within a predetermined period.
SUMMARY OF THE INVENTION
The present invention is devised in the light of the above problems and has as an objective thereof the provision of an electro-optical device capable of charging a selected pixel to a predetermined voltage within a predetermined time period, a method of driving the electro-optical device and an electronic instrument.
According to a first aspect of the present invention, there is provided an electro-optical device for supplying a voltage to a plurality of pixels and charging the pixels to a predetermined voltage within a predetermined charge period, the pixels being formed of an electro-optical material and provided to correspond to intersections of scan lines and data lines, the electro-optical device includes a scan-line drive circuit which supplies a scan signal to each of the scan lines for selecting one of the scan lines; a data-line drive circuit which supplies a data signal to each of the data lines; and a voltage transformation circuit which changes a voltage of the data signal supplied from the data-line drive circuit based on a distance between the data-line drive circuit and one of the scan lines which has been sequentially selected by the scan-line drive circuit.
According to a second aspect of the invention, there is provided an electro-optical device for supplying a voltage to a plurality of pixels and charging the pixels to a predetermined voltage within a predetermined charge period, the pixels being formed of an electro-optical material and provided to correspond to intersections of scan lines and data lines, the electro-optical device includes a scan-line drive circuit which supplies a scan signal to each of the scan lines for selecting one of the scan lines; a first data-line drive circuit which supplies a first data signal to one end of each of the data lines; a second data-line drive circuit which supplies a second data signal to the other end of each of the data lines; and a circuit which causes the second data-line drive circuit to supply the second data signal to each of the data lines in synchronism with the supply of the first data signal to each of the data lines.
According to a third aspect of the present invention, there is provided an electro-optical device for supplying a voltage to a plurality of pixels and charging the pixels to a predetermined voltage within a predetermined charge period, the pixels being formed of an electro-optical material and provided to correspond to intersections of scan lines and data lines, the electro-optical device includes a scan-line drive circuit which supplies a scan signal to each of the scan lines for selecting one of the scan lines; a first data-line drive circuit which supplies a first data signal to one end of each of the data lines; a second data-line drive circuit which supplies a second data signal to the other end of each of the data lines; and a voltage transformation circuit which changes a voltage of the second data signal supplied from the second data-line drive circuit based on a distance between the first data-line drive circuit and one of the scan lines which has been sequentially selected by the scan-line drive circuit.
REFERENCES:
patent: 4750813 (1988-06-01), Ohwada et al.
patent: 5625373 (1997-04-01), Johnson
patent: 5877737 (1999-03-01), Kim et al.
patent: 5940055 (1999-08-01), Lee
patent: 6177917 (2001-01-01), Koizumi et al.
patent: 6246385 (2001-06-01), Kinoshita et al.
Dinh Duc Q
Hogan & Hartson LLP
Liang Regina
Seiko Epson Corporation
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