Liquid crystal display device
View Patent ↗Provided is a drive circuit low in power consumption and high in display quality for a liquid crystal display device that is used in a small-sized portable device. The liquid crystal display device includes liquid crystal display elements and a liquid crystal driving circuit. The liquid crystal driving circuit is mounted to one of the four sides of a liquid crystal display panel, and is capable of outputting two-system counter electrode voltages. A variable resistor circuit having a resistance value which is variably adjusted by a register is used to correct and output a gray scale voltage according to a position of a relevant scanning signal line. Equalization is also performed by short-circuiting two counter electrode signal lines.
1. A liquid crystal display device comprising:
a first substrate;
a second substrate;
a liquid crystal composition which is held between the first substrate and the second substrate;
a plurality of pixel electrodes which are provided on the first substrate;
a counter electrode which is placed to face corresponding one of the plurality of pixel electrodes;
a switching element which supplies a data signal to corresponding one of the plurality of pixel electrodes;
a data signal line which supplies the data signal to the switching element;
a scanning signal line which supplies a scanning signal for controlling the switching element;
a counter electrode signal line which supplies a voltage to the counter electrode; and
a drive circuit which outputs the data signal and the scanning signal,
wherein the drive circuit includes a gray scale voltage generating circuit having a variable resistor circuit and an amplitude correction register,
wherein the amplitude correction register holds a plurality data items for correcting a gray scale voltage according to a position of the scanning signal line, and
wherein the variable resistor circuit has a resistance value which is varied depending on the position of the scanning signal line and the data items held by the amplitude correction register.
2. A liquid crystal display device according to claim 1 , wherein the gray scale voltage generating circuit includes a gradient adjustment register that corrects the gray scale voltage for approximating a gamma function by using the variable resistor circuit.
3. A liquid crystal display device according to claim 1 , wherein the variable resistor circuit includes a plurality of resistors, which are connected in series, and an analog switch, which short-circuits input terminals and output terminals of the plurality of resistors.
4. A liquid crystal display device comprising:
a first substrate;
a second substrate;
a liquid crystal composition which is held between the first substrate and the second substrate;
a plurality of pixel electrodes which are provided on the first substrate;
a counter electrode which is placed to face corresponding one of the plurality of pixel electrodes;
a switching element which supplies a data signal to corresponding one of the plurality of pixel electrodes;
a data signal line which supplies the data signal to the switching element;
a scanning signal line which supplies a scanning signal for controlling the switching element;
a first counter voltage line and a second counter voltage line which supply voltages to the counter electrode; and
a drive circuit which outputs the data signal and the scanning signal,
wherein the drive circuit includes a gray scale voltage generating circuit having an amplitude correction register that holds a plurality of data items for correcting a gray scale voltage according to a position of the scanning signal line,
wherein the gray scale voltage generating circuit adjusts a resistance value of a variable resistor circuit depending on the position of the scanning signal line, and thereby adjusts an amplitude of a gray scale voltage, and
wherein the resistance value of the variable resistor circuit is varied according to the data items that are held by the amplitude correction register.
5. A liquid crystal display device according to claim 4 , wherein the gray scale voltage generating circuit includes a gradient adjustment register that corrects the gray scale voltage for approximating a gamma function by using the variable resistor circuit to thereby adjust the amplitude of the gray scale voltage.
6. A liquid crystal display device according to claim 4 , wherein the variable resistor circuit includes a plurality of resistors, which are connected in series, and an analog switch, which short-circuits input terminals and output terminals of the plurality of resistors.
7. A liquid crystal display device comprising:
a first substrate;
a second substrate;
a liquid crystal composition which is held between the first substrate and the second substrate;
a plurality of pixel electrodes which are provided on the first substrate;
a counter electrode which is placed to face corresponding one of the plurality of pixel electrodes;
a switching element which supplies a data signal to corresponding one of the plurality of pixel electrodes;
a data signal line which supplies the data signal to the switching element;
a scanning signal line which supplies a scanning signal for controlling the switching element;
a first counter voltage line and a second counter voltage line which supply counter voltages to the counter electrode;
a drive circuit which outputs the data signal, the scanning signal, and the counter voltages; and
an equalizer circuit which short-circuits the first counter voltage line and the second counter voltage line,
wherein the drive circuit includes a gray scale voltage generating circuit having an amplitude correction register that holds a plurality of data items for correcting a gray scale voltage according to a position of the scanning signal line,
wherein the gray scale voltage generating circuit varies a resistance value of a variable resistor circuit depending on the position of the scanning signal line, and thereby adjusts an amplitude of a gray scale voltage, and
wherein the resistance value of the variable resistor circuit is varied according to the data items that are held by the amplitude correction register.
8. A liquid crystal display device according to claim 7 , wherein the gray scale voltage generating circuit includes a gradient adjustment register that corrects the gray scale voltage for approximating a gamma function by using the variable resistor circuit to thereby adjust the amplitude of the gray scale voltage.
9. A liquid crystal display device according to claim 7 , wherein the variable resistor circuit includes a plurality of resistors, which are connected in series, and an analog switch, which short-circuits input terminals and output terminals of the plurality of resistors.