Liquid crystal display device having drive circuit
View Patent ↗The present invention provides a liquid crystal display device which can be used in a miniaturized portable equipment, wherein the liquid crystal display device integrally incorporates a drive circuit therein so that a circuit scale can be miniaturized. A liquid crystal drive circuit includes a first drive circuit and a second drive circuit which is mounted on one side of the liquid crystal display panel. One output of the first drive circuit is connected to a plurality of signal lines and the second drive circuit supplies signals to the first drive circuit. The liquid crystal display panel includes holding capacitive elements and signals are supplied to the holding capacitive elements from the second drive circuit. The second drive circuit includes a booster circuit for supplying signals to the first drive circuit and the holding capacitive elements.
1. A liquid crystal display device comprising:
a first substrate;
a second substrate;
a 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;
a plurality of switching elements supplying video signals to the pixel electrodes;
a plurality of video signal lines supplying video signals to the switching elements;
a plurality of scanning signal lines supplying scanning signals thereby controlling the switching elements;
a first drive circuit connected to the plurality of video signal lines for supplying the video signals to the video signal lines;
a second drive circuit supplying high level and low level of scanning signals to the scanning signal lines;
a plurality of holding capacitive elements which are formed on the first substrate;
a power supply circuit mounted on the first substrate for supplying a voltage on the holding capacitive elements;
a flexible printed circuit board connected to the first substrate; and
a capacitor mounted on the flexible printed circuit board, wherein
the capacitor connects to the power supply circuit by wiring of the flexible printed circuit board,
the power supply circuit generates a first voltage,
a second voltage, which is a higher than the first voltage, is generated from the first voltage,
a third voltage, which has a reverse polarity to the first voltage, is generated from the first voltage, and
the capacitor is used in a time division manner for generating the second voltage and the third voltage.
2. A liquid crystal display device comprising:
a first substrate;
a second substrate;
a liquid crystal material arranged between the first substrate and the second substrate;
a plurality of pixel electrodes formed on the first substrate;
a plurality of switching elements supplying video signals to the pixel electrodes;
a plurality of video signal lines supplying video signals to the switching elements;
a plurality of scanning signal lines supplying scanning signals thereby controlling the switching elements;
a first drive circuit connected to the plurality of video signal lines for supplying the video signals to the video signal lines;
a second drive circuit supplying the scanning signals to the scanning signal lines;
a power source circuit mounted on the first substrate for supplying a voltage to the first or second drive circuit;
a flexible printed circuit board connected to the first substrate;
a capacitor mounted on the flexible printed circuit board, wherein
the capacitor connects to the power source circuit by wring of the flexible printed circuit board,
the power source circuit generates a first voltage,
a second voltage, which is a higher than the first voltage, is generated from the first voltage,
a third voltage, which has a reverse polarity to the first voltage, is generated from the first voltage, and
the capacitor is used in a time division manner for generating the second voltage and the third voltage.
3. A liquid crystal display device according to claim 1 , wherein the power supply circuit outputs the second voltage to the second drive circuit.
4. A liquid crystal display device according to claim 1 , wherein the power supply circuit generates a fourth voltage which is supplied to a holding capacitive element.
5. A liquid crystal display device according to claim 2 , wherein the power supply circuit outputs the second voltage to the second drive circuit.