Liquid crystal display device
It is possible to realize a driver circuit which exhibits low power consumption and high image quality in a liquid crystal display device used in miniaturized portable equipment. In a liquid crystal display device which includes a liquid crystal display element and a liquid crystal driver circuit, the liquid crystal driver circuit is mounted on one side of a liquid crystal display panel. The liquid crystal driver circuit can output counter electrode voltages of two systems and hence, the liquid crystal driver circuit can select a first mode in which the first counter voltage and the second counter voltage have the opposite polarities from each other and a second mode in which the first counter voltage and the second counter voltage have the same polarity. Due to such constitution, while driving the liquid crystal display device in the first mode, the second mode is selected depending on a video signal thus realizing power saving.
1. A liquid crystal display device comprising:
a first substrate;
a second substrate;
liquid crystal composition which is sandwiched between the first substrate and the second substrate;
a plurality of pixel electrodes which are formed on the first substrate;
counter electrodes which are arranged to face the pixel electrodes in an opposed manner;
switching elements which are configured to supply video signals to the pixel electrodes;
video signal lines which are configured to supply video signals to the switching elements;
scanning signal lines which are configured to supply scanning signals for controlling the switching elements;
first counter electrode signal lines which are configured to supply a first voltage to the counter electrodes;
second counter electrode signal lines which are configured to supply a second voltage to the counter electrodes; and
a driver circuit which is configured to output the video signals and the scanning signals, wherein
a first scanning signal line and a second scanning signal line which constitute two neighboring scanning signal lines are provided with first pixel electrodes to which the video signals are supplied from the switching elements which are controlled in response to the scanning signals supplied through the first scanning signal line, and second pixel electrodes to which the video signals are supplied from the switching elements which are controlled in response to the scanning signals supplied through the second scanning signal line,
a first counter electrode signal line is connected to the counter electrodes which face the first pixel electrodes in an opposed manner,
a second counter electrode signal line is connected to the counter electrodes which face the second pixel electrodes in an opposed manner,
the liquid crystal display device is driven in a first mode in which polarity of a voltage applied to the first counter electrode signal line and polarity of a voltage applied to the second counter electrode signal line are set opposite to each other during a first scanning period in which the scanning signals are outputted to the first scanning signal line, and
the liquid crystal display device is configured to be capable of selecting a second mode in which the voltage applied to the first counter electrode signal line and the voltage applied to the second counter electrode signal line have the same polarity during a retracing period from a point of time that outputting of the scanning signal to the scanning signal line on the last row is finished to a point of time that outputting of the scanning signal to the scanning signal line on a start row is started.
2. A liquid crystal display device according to claim 1 , wherein the driver circuit includes a first voltage generation circuit which is configured to output the first voltage and a second voltage generation circuit which is configured to output the second voltage.
3. A liquid crystal display device according to claim 1 , wherein the driver circuit includes,
a first voltage generation circuit which is configured to output the first voltage and a second voltage generation circuit which is configured to output the second voltage;
a first switching circuit which is configured to change over the connection between the first voltage generation circuit and the first counter electrode signal line or the second counter electrode signal line; and
a second switching circuit which is configured to change over the connection between the second voltage generation circuit and the first counter electrode signal line or the second counter electrode signal line.
4. A liquid crystal display device comprising:
a first substrate;
a second substrate;
liquid crystal composition which is sandwiched between the first substrate and the second substrate;
a plurality of pixel electrodes which are formed on the first substrate;
counter electrodes which are arranged to face the pixel electrodes in an opposed manner;
switching elements which are configured to supply video signals to the pixel electrodes;
video signal lines which are configured to supply video signals to the switching elements;
scanning signal lines which are configured to supply scanning signals for controlling the switching elements;
first counter electrode signal lines which are configured to supply a first voltage to the counter electrodes;
second counter electrode signal lines which are configured to supply a second voltage to the counter electrodes; and
a driver circuit which is configured to output the video signals and the scanning signals, wherein
the driver circuit is configured to be capable of changing over an operation of the liquid crystal display device between a first mode in which the scanning signals are outputted while inverting polarity of the first voltage and polarity of the second voltage and a second mode in which the scanning signals are outputted while allowing the polarity of the first voltage and the polarity of the second voltage to have the same phase at the time of performing power saving driving in which the scanning signals are supplied to the plurality of scanning signal lines.
5. A liquid crystal display device according to claim 4 , wherein the driver circuit includes a first voltage generation circuit which is configured to output the first voltage and a second voltage generation circuit which is configured to output the second voltage.
6. A liquid crystal display device according to claim 4 , wherein the driver circuit includes:
a first voltage generation circuit which is configured to output the first voltage and a second voltage generation circuit which is configured to output the second voltage;
a first switching circuit which is configured to change over the connection between the first voltage generation circuit and the first counter electrode signal line or the second counter electrode signal line; and
a second switching circuit which is configured to change over the connection between the second voltage generation circuit and the first counter electrode signal line or the second counter electrode signal line.
7. A liquid crystal display device comprising:
a first substrate;
a second substrate;
liquid crystal composition which is sandwiched between the first substrate and the second substrate;
a plurality of pixel electrodes which are formed on the first substrate;
counter electrodes which are arranged to face the pixel electrodes in an opposed manner;
switching elements which are configured to supply video signals to the pixel electrodes;
video signal lines which are configured to supply video signals to the switching elements;
scanning signal lines which are configured to supply scanning signals for controlling the switching elements;
first counter electrode signal lines which are configured to supply a first voltage to the counter electrodes;
second counter electrode signal lines which are configured to supply a second voltage to the counter electrodes; and
a driver circuit which is configured to output the video signals and the scanning signals, wherein
the driver circuit is configured to be capable of changing over an operation of the liquid crystal display device between a first mode in which the scanning signals are outputted while inverting polarity of the first voltage and polarity of the second voltage and a second mode in which the scanning signals are outputted while allowing the polarity of the first voltage and the polarity of the second voltage to have the same phase at the time of performing a power saving operation in which the video signals are outputted from an inverter circuit provided to an output circuit.
8. A liquid crystal display device according to claim 7 , wherein the driver circuit includes a first voltage generation circuit which is configured to output the first voltage and a second voltage generation circuit which is configured to output the second voltage.
9. A liquid crystal display device according to claim 7 , wherein the driver circuit includes,
a first voltage generation circuit which is configured to output the first voltage and a second voltage generation circuit which is configured to output the second voltage;
a first switching circuit which is configured to change over the connection between the first voltage generation circuit and the first counter electrode signal line or the second counter electrode signal line; and
a second switching circuit which is configured to change over the connection between the second voltage generation circuit and the first counter electrode signal line or the second counter electrode signal line.