JP2004118212A5

JP2004118212A5 -

Info

Publication number: JP2004118212A5
Application number: JP2003353089A
Authority: JP
Filing date: 2003-10-14
Publication date: 2005-06-16

Claims

A gradation voltage generating circuit that includes a variable resistor and generates a plurality of gradation voltages by dividing a reference voltage by the variable resistor;
A gradation voltage selection circuit that selects a gradation voltage corresponding to input display data and output to the display panel from the plurality of gradation voltages generated by the gradation voltage generation circuit;
A display drive circuit comprising a setting register for setting a resistance value of the variable resistor.

The display drive circuit according to claim 1, wherein a resistance value of the variable resistor set in the setting register is changed according to a type of display image of the display data.

On a graph with the vertical axis representing luminance and the horizontal axis representing display data, the luminance characteristic for the display data is a convex curve and a concave curve based on a straight line connecting the low luminance point and the high luminance point. The display driving circuit according to claim 1, wherein a resistance value of the variable resistor set in the setting register is changed so that the distance between the display resistor and the setting resistor can be changed.

When the display image of the display data is a natural image, the setting register is configured so that the luminance characteristic for the display data has a convex shape with reference to a straight line connecting the point having the low luminance and the point having the high luminance. The resistance value of the variable resistor to be set changes,
When the display image of the display data is computer graphics or text, the luminance characteristic for the display data is a concave shape with reference to a straight line connecting the low luminance point and the high luminance point. 4. The display driving circuit according to claim 3, wherein a resistance value of the variable resistor set in the setting register changes.

5. The display driving circuit according to claim 1, wherein the setting register sets a resistance value of the variable resistor after the power is turned on and before display of the display data is started.

A display driving circuit according to any one of claims 1 to 6;
A display panel having a data line and a scanning line connected to the display driving circuit;
A display device comprising: a scan driver for selecting the scan line.

In a liquid crystal driving circuit for driving the data line of a liquid crystal panel that includes a data line and a scanning line and applies a voltage to the liquid crystal,
A latch address control circuit for sequentially generating latch signals for fetching display data;
A first holding circuit for fetching and holding the display data according to the latch signal;
A second holding circuit for further capturing and holding the display data held by the first holding circuit at the same time according to a horizontal synchronizing signal for the output data line;
A gradation voltage generation circuit that inputs a plurality of different reference voltages, divides the plurality of different reference voltages by a voltage dividing resistor including a plurality of variable resistors, and generates a plurality of gradation voltages;
A gradation voltage selection circuit that selects a gradation voltage corresponding to display data held by the second holding circuit from the plurality of gradation voltages generated by the gradation voltage generation circuit;
An operational amplifier for inputting the gradation voltage and the offset voltage selected by the gradation voltage selection circuit;
An amplifier that divides an output voltage of the operational amplifier and includes a voltage dividing resistor composed of one or a plurality of variable resistors to be input to the operational amplifier, and amplifies and outputs the gradation voltage selected by the gradation voltage selection circuit Circuit,
Setting data for controlling a voltage dividing ratio of the voltage dividing resistor in the gradation voltage generating circuit and a setting register for setting setting data for controlling the voltage dividing ratio of the voltage dividing resistor in the amplifier circuit;
With the setting data for controlling the voltage dividing ratio of the voltage dividing resistor in the gradation voltage generating circuit, it is possible to adjust the intermediate gradation part of the gradation-voltage characteristic,
By setting data for controlling the voltage dividing ratio of the voltage dividing resistor in the amplifier circuit, it is possible to adjust the slope of the entire gradation-to-voltage characteristic by fixing one-side end gradation,
With the offset voltage, the entire gradation versus voltage characteristic can be shifted up and down,
2. A liquid crystal driving circuit according to claim 1, wherein setting data is set in the setting register by a clock comprising a product of a latch signal from the latch address control circuit and a setting enable signal.

8. The liquid crystal driving circuit according to claim 7, wherein the variable resistor of the gradation voltage generating circuit and / or the amplifier circuit includes a plurality of resistors and a switch for removing a resistance component of each resistor in the variable resistor.

8. The liquid crystal drive according to claim 7, wherein the setting register for setting the amplification degree of each operational amplifier of the amplifier circuit is provided for each of R, G, and B, and the setting can be changed for each color. circuit.

The offset voltage of the amplifier circuit includes a plurality of settable variable resistors, and is generated by dividing an offset reference voltage and a common voltage by the variable resistors, and the voltage value can be changed. 8. A liquid crystal driving circuit according to 7.

A liquid crystal driving circuit according to any one of claims 7 to 10,
A liquid crystal panel having a data line and a scanning line and applying a voltage to the liquid crystal;
A scan driver for driving a scan line of the liquid crystal panel;
A control circuit for setting a gradation voltage output from the liquid crystal driving circuit and controlling the liquid crystal driving circuit and the scan driver;
A reference voltage generation circuit for generating a reference voltage of the liquid crystal driving circuit,
The liquid crystal display device, wherein the liquid crystal driving circuit outputs a gradation voltage from the amplifier circuit to the liquid crystal panel.