KR20040026217A - Driving apparatus and method for display device - Google Patents

Abstract

PURPOSE: An apparatus for driving a display device and its method are provided to prevent voltage drop due to scan resistance and to make constant brightness of a screen. CONSTITUTION: According to the apparatus for driving a display device displaying image data on a display panel(25) comprising a number of cells, an image data detection part(57) detects inputted image data and converts it into a voltage and then outputs it. A constant voltage part(52) outputs a voltage by receiving an external input voltage. A constant current part(53) outputs a current by receiving the voltage from the constant voltage part. A constant voltage constant current control part(100) outputs a control signal controlling the constant voltage part by receiving the voltage from the constant voltage part and the voltage from the image data detection part, and controls the constant current part by receiving the voltage from the image data detection part. And a data driver part(23) receives the current from the constant current part and then outputs image data to the display panel.

Description

Display device driving device and method {DRIVING APPARATUS AND METHOD FOR DISPLAY DEVICE}

The present invention relates to a display element driving apparatus and method, and more particularly to a display element driving apparatus and method that can make the brightness of the entire screen constant by controlling the amount of current input to the panel.

Recently, wireless mobile communication such as IMT-2000 has been in the spotlight. Displays in such wireless mobile communications require good quality, high speed, low weight and low power consumption.

A switching element capable of satisfying the above-mentioned function is a metal-insulator-metal (hereinafter, referred to as 'MIM'). MIM is an electrode structure formed of a thin film. Since the resistive and condenser components are very large, low voltage and high current are required for driving due to the characteristics of the panel.

FIG. 1 is a cross-sectional view illustrating a general MIM cell structure. In the MIM device, when a predetermined voltage is applied to the data electrode 11 and the scan electrode 12, electrons e are emitted from the scan electrode 12. It is emitted through the insulating layer 13 and the data electrode 11 by the quantum mechanical tunnel effect.

The emitted electrons are accelerated toward the anode to which the phosphor is applied by the anode 14 voltage, which is a larger anode voltage. When the electrons collide with the phosphor, energy is generated, and the electrons in the phosphor It is excited here and then falls off.

FIG. 2 is a block diagram showing the structure of a conventional display element driving apparatus. When the image data 21 is input, the PWM unit 22 receives the image data 21 and outputs the pulse width modulation. The data driver 23 receives the image data 21 output by modulating the pulse width from the PWM unit 22 and outputs a data pulse to the data electrode 11, and outputs a scan pulse to the scan electrode 12. A scan driver 24 and a panel 25 for receiving data pulses output from the data driver 23 and scan pulses output from the scan driver 24 to output an image.

Referring to the operation of the conventional display device driving device configured as described above, when the image data 21 is input, the PWM unit 22 receives the image data 21 and outputs the pulse width modulated, and the data driver 23 The PWM unit 22 receives the image data 21 output by modulating the pulse width and outputs a data pulse to the data electrode 11.

In addition, the scan driver 24 outputs a scan pulse to the scan electrode 12, the panel 25 receives the data pulse output from the data driver 23 and the scan pulse output from the scan driver 24. The image is output while the data pulse and the scan pulse are synchronized.

3 is a block diagram illustrating a detailed configuration of the scan driver 24. The timing controller 24a receives the image data 21 and outputs a control signal, and the control signal output from the timing controller 24a. A buffer 24b for receiving and temporarily storing the signal and amplifying and outputting the signal; and a photocoupler 24c for receiving the control signal output from the buffer 24b, passing the control signal to the secondary side, and electrically separating the primary side and the secondary side. And a buffer 24d for temporarily storing the control signal output from the photocoupler 24c and amplifying and outputting the signal, and a scan driving IC for receiving a control signal output from the buffer 24d and outputting a scan pulse ( 24e).

FIG. 4 is a display diagram showing the difference in brightness according to the load of the panel 25 of the conventional display device driving apparatus. As shown in FIG. It was. That is, all the cells in the portion where the black signal 41 is located are turned off, and all cells except the black signal 41 are in an on state.

When the black signal 41 is output to the panel 25, the left and right portions are relatively brighter than the upper and lower portions of the panel 25 on which the black signal 41 is output, as shown. This phenomenon occurs because each cell operates as a resistance component during light emission, and thus the amount of current flowing through the data line of the panel 25 during image output is not constant.

In more detail, the amount of current required by each data line exceeds the amount of current supplied by the amount of current required in the upper and lower portions of the black signal 41, which is a heavy load on the panel 25. It is driven by less current, which lowers the brightness of the screen. For example, if the maximum amount of current that can be supplied by the data driver 23 is 10 I, the current of about 12 I is required in the upper and lower portions of the black signal 41 output. Therefore, driving is performed in a state where the current is as low as 2I, and the brightness of the screen becomes dark. On the other hand, the left and right portions of the black signal 41 are output as much as 6I current, and the data driver 23 supplies as much current as desired to be output without deteriorating the brightness of the screen.

In addition, although not shown in FIG. 4, if a scan resistance exists between a cell and a current flows in the scan resistance during image output, the product of the scan resistance and the current is generated as a voltage drop, and the panel ( There is a difference in brightness on the left and right of 25). That is, the upper and lower portions of the black signal shown in FIG. 4 are about 70 when the left side is 80, and when the left and right portions of the black signal are 100, the right side is about 90 degrees.

As described above, the conventional display element driving apparatus has a problem in that the brightness of the screen is lowered because the amount of current flowing through each cell is not constant because the cell operates as a resistance component during light emission.

In addition, there is a problem that a voltage drop occurs due to the scan resistance between the cells and the brightness difference between the left and right screens of the panel due to the voltage drop.

Accordingly, in view of the above problems, the present invention provides a constant voltage unit for making an input voltage at a predetermined level according to the amount of input image data, and receives a predetermined level of voltage output from the constant voltage unit to supply a current having a predetermined level. It is an object of the present invention to provide a display device driving apparatus and method capable of preventing the voltage drop caused by the scan resistance and making the brightness of the screen constant by configuring the constant current unit to output the device.

1 is a cross-sectional view showing a general MIM cell structure.

Figure 2 is a block diagram showing the configuration of a conventional display element drive device.

FIG. 3 is a block diagram illustrating a detailed configuration of the scan driver shown in FIG. 2.

4 is a brightness difference display according to the panel load of the conventional display element driving device.

5 is a block diagram showing a configuration of a display device driving apparatus of the present invention.

6 is a brightness difference display according to the panel load to which the display device driving apparatus of the present invention is applied.

** Description of the symbols for the main parts of the drawings **

22: PWM unit 23: data driver

24: scan driver 25: panel

52: constant voltage portion 53: constant current portion

54: D / A part 55: control part

56 feedback unit 57 image data detection unit

100: constant voltage constant current control unit

In the display driving apparatus for displaying predetermined image data on a display panel having a plurality of cells, the display element driving apparatus of the present invention for achieving the above object, the voltage of a predetermined level by detecting the amount of the input image data A video data detection unit for converting and outputting a signal; a constant voltage unit receiving an external input voltage and outputting a voltage of a predetermined level; a constant current unit receiving a voltage of a predetermined level output from the constant voltage unit and outputting a current of a predetermined level; The constant current unit receives a voltage of a predetermined level output from the constant voltage unit and a voltage of a predetermined level output from the image data detection unit, and outputs a control signal for controlling the constant voltage unit, and receives the voltage of the predetermined level output from the image data detection unit. A constant voltage constant current control unit for controlling and a predetermined level output from the constant current unit To receive the current configured by including a data driver for outputting image data to the display panel is characterized.

A display device driving method of the present invention for achieving the above object is a display driving method for displaying a predetermined image data on a display panel having a plurality of cells, the step of detecting the amount of image data input to the display panel And controlling a driving current for displaying the image data on the display panel according to the detected amount of image data.

Preferred embodiments of the display device driving apparatus and method of the present invention having the above characteristics will be described in detail with reference to the drawings.

Fig. 5 is a block diagram showing the configuration of the display element driving apparatus of the present invention. The image data detecting unit 57 detects the amount of image data input to a conventional display driving apparatus and outputs a voltage of a predetermined level. A constant voltage unit 52 that receives the 51 and outputs a voltage of a predetermined level, and a constant current unit that receives a predetermined level of voltage output from the constant voltage unit 52 and outputs a current of a predetermined level to the data driver 23 ( 53) and a control signal for controlling the constant voltage unit 52 by receiving the voltage of the predetermined level output from the constant voltage unit 52 and the voltage of the predetermined level output from the image data detection unit 57, and outputting the control signal. A constant voltage constant current controller 100 for controlling the constant current unit 53 by receiving a voltage of a predetermined level output from the image data detector 57 is configured.

In addition, the constant voltage constant current control unit 100 receives a voltage of a predetermined level output from the image data detection unit 57 and converts it into an analog voltage and outputs the analog voltage, and outputs the constant voltage unit 52. A feedback unit 56 for receiving a voltage of a predetermined level and outputting a voltage corresponding to the voltage of the predetermined level; an analog voltage output from the D / A unit 54 and a voltage output from the feedback unit 56; The control unit 55 is configured to receive a pulse signal having a width having a predetermined size to the constant voltage unit 52.

Referring to the operation and operation of the display device driving apparatus of the present invention configured as described above are as follows.

First, when R, G, and B data, which is the image data 21, are input, the PWM unit 22 pulse-modulates the image data 21 and outputs the same to the data driver 23. In addition, the amount of the image data 21 input from the image data detector 57 is detected to output a voltage of a predetermined level, and the D / A unit 54 outputs a predetermined level of the predetermined level output from the image data detector 57. It receives the voltage and converts it into an analog voltage of a predetermined level and outputs it.

The controller 55 receives the analog voltage of the predetermined level output from the D / A unit 54 and outputs a pulse signal having a width of a predetermined size, and the constant voltage unit 52 outputs the pulse signal. The input voltage 51 is output at a predetermined level by a pulse signal having a predetermined width, and the feedback section 56 receives the predetermined level voltage output from the constant voltage section 52 and corresponds to the voltage. Is output to the controller 55.

Then, the control unit 55 receives the voltage output from the feedback unit 56 and the analog voltage of the predetermined level output from the D / A unit 54 and outputs a pulse signal having a width having a predetermined size. In operation 52, the pulse signal output from the controller 55 is received, and the input voltage 51 is output again at a predetermined level. Through such a process, the voltage of the predetermined level output from the constant voltage unit 52 is stabilized.

In addition, the constant current unit 53 receives an analog voltage of the predetermined level output from the D / A unit 54 and converts the predetermined level voltage output from the constant voltage unit 52 into a current of a predetermined level. .

The data driver 23 receives a current of a predetermined level output from the constant current unit 56 and outputs the pulse width modulated image data 21 to the data electrode of the panel, and the scan driver 24 of the panel 25 The image data 21 is output to the panel 25 while outputting a scan pulse to the scan electrode and synchronizing the data pulse with the scan pulse.

The display device driving apparatus of the present invention operating as described above will be described in detail according to the input image data 21 amount.

When the amount of image data 21 to be input is large, a large amount of current is required because the number of cells is turned on. Referring to the process for supplying a large amount of current, first, when a large amount of image data 21 is input, the image data detector 57 detects the amount of the image data 21 and outputs a high level voltage. The D / A unit 54 converts the high level voltage output from the image data detection unit 57 into an analog voltage and outputs the analog voltage.

Then, the controller 55 receives the analog voltage output from the D / A unit 54 and outputs a pulse signal having a large width, and the constant voltage unit 52 outputs a large pulse signal output from the controller 55. The output voltage 51 is received at a large level. In order to stabilize the voltage of the large level output from the constant voltage unit 52, the feedback unit 56 converts the voltage to a predetermined level and outputs the voltage to the control unit 55.

In addition, the constant current unit 53 receives the analog voltage output from the D / A unit 54 receives a large level of voltage output from the constant voltage unit 52 receives the current corresponding to the corresponding amount of data driver 23 Will output

Even when a large amount of image data 21 is input through the above process, a large amount of current is received by the data driver 23 to supply a constant current to each cell, thereby preventing voltage drop and removing a difference in screen brightness.

On the contrary, when the amount of the input image data 21 is small, the number of turning on the cells is small, so that driving with only a small current is possible. Referring to the process for supplying a small amount of current, first, when a small amount of image data 21 is input, the image data detector 57 detects the amount of the image data 21 and outputs a low level voltage. The D / A unit 54 converts the low level voltage output from the image data detector 57 into an analog voltage and outputs the analog voltage.

Then, the control unit 55 receives the analog voltage output from the D / A unit 54 and outputs a pulse signal having a small width, and the constant voltage unit 52 outputs a small width pulse signal output from the control unit 55. The output voltage 51 is received at a low level. In order to stabilize the low level voltage output from the constant voltage unit 52, the feedback unit 56 converts the voltage to a predetermined level and outputs the voltage to the control unit 55.

In addition, the constant current unit 53 receives the analog voltage output from the D / A unit 54 receives the low level voltage output from the constant voltage unit 52 receives the current corresponding to the current corresponding to the data driver 23 Will output

When a small amount of image data 21 is input through the above process, a current is supplied to the data driver 23 in an amount sufficient to output the image data 21 to display the input image data 21 with screen brightness. The power consumption can be reduced by outputting to the panel without any difference and driving with a smaller amount of current than before.

FIG. 6 is a display diagram showing the difference in brightness according to the panel load to which the display element driving apparatus and method of the present invention are applied. As shown in FIG. 6, a black signal having a predetermined size having a rectangular shape is applied to the center of the panel 25.

As shown, it can be seen that there is no difference in brightness between the upper and lower sides and the left and right portions to which the black signal, which is the image data 21, is input. That is, the upper and lower portions of the black signal, which is a heavy load, are supplied with a large amount of current so that a constant current flows in each cell, so that the difference in brightness of the screen is eliminated without voltage drop, and the left and right sides of the black signal, which is a light load, are reduced. By supplying as much current as necessary, you can see that there is no difference in brightness of the screen.

As such, by applying the display driving apparatus of the present invention, a difference in screen brightness generated when a large amount of image data 21 is input in the conventional display driving apparatus can be eliminated. Can be driven with a small amount of power can reduce the power consumption.

As described in detail above, the present invention uses a constant voltage unit and a constant current unit capable of supplying by adjusting the amount of current to the data driver according to the amount of input image data, thereby keeping the brightness constant throughout the screen. There is an effect to reduce the power consumption due to the constant voltage and constant current operation according to the amount of video data to be.

Claims (4)

A display driving apparatus for displaying predetermined image data on a display panel having a plurality of cells, An image data detector which detects an amount of input image data and converts the image data into a voltage having a predetermined level; A constant voltage unit configured to receive an external input voltage and output a voltage having a predetermined level; A constant current unit receiving a voltage of a predetermined level output from the constant voltage unit and outputting a current of a predetermined level; The control unit controls the constant voltage unit by receiving a voltage of a predetermined level output from the constant voltage unit and a voltage of a predetermined level output from the image data detection unit, and outputs a control signal for controlling the constant voltage unit, and receives the voltage of the predetermined level output from the image data detection unit. A constant voltage constant current control unit controlling the unit; And a data driver for receiving a predetermined level of current output from the constant current unit and outputting image data to the display panel. The apparatus of claim 1, wherein the constant voltage constant current control unit comprises: a D / A unit which receives a voltage of a predetermined level output from the image data detector and converts the voltage into an analog voltage; A feedback unit receiving a voltage of a predetermined level output from the constant voltage unit and outputting a voltage corresponding to the voltage of the predetermined level; And a controller for receiving an analog voltage output from the D / A unit and a voltage output from the feedback unit and outputting a pulse signal having a width having a predetermined size to the constant voltage unit. In a display driving method for displaying predetermined image data on a display panel having a plurality of cells, Detecting an amount of image data input to the display panel; And controlling a driving current for displaying the image data on the display panel according to the detected amount of image data. The method of claim 3, further comprising: outputting a constant voltage having a predetermined level according to the amount of image data; And outputting a constant level of a predetermined level based on the output constant voltage of the predetermined level and the amount of the image data.