KR100304867B1 - Scanning variable liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display with changeable scanning mode is provided to realize a double-speed scanning mode as well as a general scanning mode in an integrated system through a horizontal driving circuit employing a scanning mode selection part. CONSTITUTION: A liquid crystal display in which scanning manner is changeable includes a horizontal driving circuit for driving horizontal lines of a pixel array(10) in sequence, wherein the horizontal driving circuit includes a shift register(21) for outputting a pulse in sequence, a buffer(22) to output the pulse to the pixel array after temporarily storing the pulse for reducing the distortion of the pulse. and a mode selection part(23) positioned between the shift register and the buffer for controlling a number of output scanning lines according to control signals(IN1-IN3) to select a double-speed scanning mode or a general scanning mode.

Description

LCD with variable scanning method

1 is a block diagram of a conventional liquid crystal panel.

2 is a block diagram of the horizontal drive circuit of FIG.

3 is a block diagram of a horizontal driving circuit of the liquid crystal display device according to the present invention.

4 is a detailed circuit diagram of mode selection of FIG.

5 (a) and 5 (b) are operation timing diagrams of the present invention.

* Explanation of symbols for main parts of the drawings

1: transparent substrate 2: horizontal scanning line

3: vertical signal line 10: pixel array

20: horizontal drive circuit 21: shift register

22: buffer 23: mode selector

30: vertical drive circuit IN1-IN3: control signal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a variable scan type, and more particularly, to a liquid crystal display device having a variable scan type to enable driving of a general scan method and a double speed scan method according to conditions of an external image signal. It is about.

In general, in the liquid crystal display, when the pixel array 20 and the driving circuit are embedded on the uniform transparent substrate 1 as shown in FIG. 1, the horizontal driving circuit 20 sequentially drives horizontal lines of the pixel array 10. The vertical driving circuit 30 applies an image signal to each pixel.

At this time, since the horizontal drive circuit 20 is connected to each horizontal scan line 2, the number of outputs of the horizontal drive circuit 20 is designed to be equal to the number of horizontal scan lines 2, such a conventional horizontal The configuration of the driving circuit can be shown in FIG. 2, which is a shift register 21 for sequentially outputting pulses and a buffer for temporarily storing the output of the shift register 21 to reduce the distortion of the pulse. 22).

When the output pulses of the shift register 21 are sequentially applied to the horizontal scan line 2, the horizontal drive circuit 20 operates one horizontal line during the period of these output pulses, and the vertical drive circuit during each horizontal scanning period. Each pixel is operated by receiving a video signal from 30.

However, in the conventional horizontal driving circuit, the driving method is fixed by designing the output to correspond to the horizontal scan line of the pixel array, and thus requires an image signal.

In other words, when the LCD is operated with a video signal such as a TV signal, a video signal driving method generally used is a general scanning method for driving one screen divided into 240 horizontal scanning lines and a double speed driving method for increasing the driving speed to 480 scanning lines. When the driving circuit is built on the transparent substrate, it is fixed to any one driving method and is designed according to the driving method. Therefore, the driving circuit cannot be selected and is limited to only one driving method.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and an object of the present invention is to configure a mode selector for controlling an output scan player in a horizontal drive circuit so that a general scan method and a double scan method can be selected according to the condition of an external video signal. The present invention provides a liquid crystal display device capable of varying the scanning method.

A feature of the present invention for achieving the above object is a liquid crystal display device in which a pixel array and horizontal and vertical driving circuits are built on the same transparent substrate, and double-speed scanning outputs all signals as sequential pulses to the horizontal driving circuit as they are. The present invention relates to a liquid crystal display device having a variable scan type that includes a mode selector configured to allow selection of a general scan method such that two scanning methods and two horizontal scanning lines are output in a pair.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a horizontal driving circuit of the liquid crystal display according to the present invention. The voltage and the positive clock CLK of the general horizontal driving circuit 20 are shifted between the shift register 21 and the buffer 22. Subclock And a mode selector 23 for controlling the output scanning bow according to the control signals IN1 to IN3 provided by the combination of < RTI ID = 0.0 >)< / RTI > Is configured to output 480 sequential pulses.

FIG. 4 is a detailed circuit diagram of the mode selector 23 of FIG. 3. The control signal IN1 to IN3 and the control signal IN1 to IN3 according to the scanning method to be selected are switched and output according to the inverted signal. It consists of a plurality of analog switches for controlling the scanning player.

5 (a) and 5 (b) show the operation timing diagram of the horizontal drive circuit according to the present invention, where (GSP) is a start pulse, (CLK), ( ) Is the normal clock and sub-clock, and (OUT1 ~ OUT480) is the output horizontal scan line (for TV).

In the present invention configured as described above, in order to select the double speed scanning method, a constant voltage is applied to the control signal IN1 terminal, and a positive clock used to operate the shift register 21 to the control signals IN2 and IN3 terminals. (CLK) and subclocks ( ), 480 sequential horizontal scan pulses output from the shift register 21 are output to the pixel array 10 through the buffer 22 as they are.

Therefore, the double scan method is realized.

That is, as shown in FIG. 5 (a), since the control signal IN1 is applied with a constant voltage, the control signal IN1 is kept high, and the control signals IN2 and IN3 are the positive clock CLK used for the shift register 21. Subclock ) Is used.

In addition, it can be seen that the output horizontal scan lines are sequentially output one by one to 480 lines OUT1 to OUT480.

On the other hand, in order to select the general scanning method, a negative voltage is applied to the control signal IN1 terminal, and a constant voltage and a negative voltage are alternately applied to the control signal IN2 and IN3 terminals each time the screen changes.

Then, 480 output pulses output from the shift register 21 become the same pulses two by two, and 240 sequential output pulses are output to the pixel array 10 through the buffer 22 to realize the general scanning method.

At this time, each time the screen is changed, the scanning lines to be bundled are changed. For example, in the first screen (the first field), the scanning lines are bundled into the scanning lines 1 and 2, the scanning lines 3 and 4, etc., and the next screen (two In the second field), the second and third scan lines, the fourth and fifth scan lines, and the like.

The reason for doing this is to obtain a clearer and clearer image.

As shown in FIG. 5 (b), in the first field (Field 1), all of the control signals IN1 to IN3 are applied in a low state, and in the second field (Field 2), the control signal IN1 is low. In the state, it can be seen that the control signals IN2 and IN3 are applied in the high state of the constant voltage.

In the horizontal scan line output from the first field, the scan lines 1 and 2 are the same, and the scan lines 3 and 4 are the same, so the two scan lines are output as one scan line, and thus 240 scan lines are output. In the second field, since the scan lines 2 and 3 are the same, and the scan lines 4 and 5 are the same, two scan lines are output as one scan line and thus 240 scan lines are output.

As described above, according to the present invention, a liquid crystal display having a relatively complicated system and a high operating frequency by a liquid crystal display device having a horizontal drive circuit having a mode selection unit having a selection function of a double speed scanning method and a general scan method is provided. Since the display device can be implemented in the same system, it is possible to improve the efficiency of the system and to reduce the process cost which greatly affects the manufacturing cost.

Claims (5)

Liquid crystal in which the pixel array 10 and the horizontal driver circuit 20 for sequentially driving the horizontal lines of the pixel array 10 and the vertical driver circuit 30 for applying an image signal to each pixel are embedded on the same transparent substrate. In the display device, the horizontal drive circuit 20 includes a shift register 21 for sequentially outputting pulses and a buffer 22 for temporarily storing the outputs to supply the output to the pixel array in order to reduce distortion of the pulses. It is located between the shift register and the buffer and outputs the output of the shift register 21 as it is by the control signals IN1 to IN3, or controls the output scan player to output two outputs in one pair. A liquid crystal display device having a variable scanning method, comprising a mode selecting unit (23) for selecting a method. 2. The control signal IN1 to IN3 of claim 1, wherein the control signal IN1 to IN3 includes a voltage used for the horizontal driving circuit 20, a positive clock CLK, and a sub clock. And a scan type variable liquid crystal display device, characterized in that provided in combination. The liquid crystal display of claim 1, wherein the mode selector 23 comprises a plurality of analog switches switched according to the control signals IN1-IN3 to select an output scan player. Device. The liquid crystal display of claim 1, wherein the scanning player according to the double speed scanning method and the general scanning method corresponds to a scanning player of a general TV. 2. The scanning method according to claim 1, wherein in the case of driving in the general scanning method, the scan lines of n and n + 1 are one set in one screen, and the scan lines of n + 1 and n + 2 are set in one screen in the next screen. Liquid crystal display device of variable type.