KR20080049563A - Dual display device and driving method thereof - Google Patents

Abstract

A dual display apparatus and a method for driving the same are provided to reduce the line load of panel by connecting selectively first and second display panel using a switching unit. A dual display apparatus includes first and second display panel(124,128), panel drivers(130,132,134), a controller(120), and a switching unit(144). The first and second display panel include pixel cells formed at areas, which are defined by first data and first gate lines, and second data and second gate lines respectively. The panel drivers drive the first and second display panel. The controller controls the panel drivers. The switching unit selectively connects the first display panel to second display panel under control of the controller.

Description

Dual display and driving method {DUAL DISPLAY DEVICE AND DRIVING METHOD THEREOF}

1 illustrates a conventional dual display device;

2 illustrates a dual display device according to an exemplary embodiment of the present invention.

3 is a circuit diagram illustrating a switching unit illustrated in FIG. 2.

4 is a diagram illustrating a dual display device according to another exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

20: data driver 24: first display panel

26 conductive film 28 second display panel

30: data driver 32: first gate driver

34: second gate driver 36: first data line

38: second data line 40: first gate line

42: second gate line 120: control part

124: first display panel 126: conductive film

128: second display panel 130: data driver

132: first gate driver 134: second gate driver

136: first data line 138: second data line

140: first gate line 142: second gate line

144: switching unit 146: timing controller

148: power supply

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device, and more particularly, to a dual display device and a driving method thereof capable of improving image quality uniformity.

As the information society develops, the demand for display devices has been verified in various forms.In response, the liquid crystal display device (LCD), plasma display panel (PDP), electro luminescent display (ELD), and vacuum fluorescent (VFD) have been recently developed. Various flat panel display devices have been studied, and some are already used as display devices in various equipments.

Among the flat panel display devices, LCDs have excellent image quality and are characterized by advantages such as light weight, thinness, and low power consumption. Therefore, televisions and computers that receive and display broadcast signals in addition to mobile uses such as monitors of notebook computers are used for mobile image display devices. Various monitors are developed.

In addition, as mobile phones become more commonplace, small liquid crystal displays for mobile phones are widely used. Among these mobile phones, the clamshell mobile phone displays display information indicating the operation state of the mobile phone only when the folder is opened, for example, the antenna icon (received electric field strength), the current time, the out of call range, the battery remaining status, and the various function setting states. You can check it. In other words, the conventional clamshell mobile phone is inconvenient to check the flat panel display after opening the folder.

Accordingly, a dual clamshell cell phone having both an inner and an outer window and which can easily check the display information even when the folder is closed has been developed. Here, as the display window of the dual clamshell cellular phone, a dual type liquid crystal display device using a dual liquid crystal display device has been adopted.

Hereinafter, a conventional dual display device will be described with reference to the accompanying drawings.

1 is a diagram illustrating a conventional dual display device.

Referring to FIG. 1, a conventional dual display device includes a first display panel 24 implementing a main image, a second display panel 28 implementing a sub-picture, a first display panel 24, and a second display panel. A conductive film 26 connecting the display panel 28, drivers 30, 32, and 34 driving the first display panel 24 and the second display panel 28, and drivers 30, 32, and 34. A control unit 20 for supplying a control signal.

The first display panel 124 may include a thin film transistor (TFT) formed in each pixel region defined by the plurality of first gate lines 140 and the plurality of first data lines 136, and a TFT. And a liquid crystal capacitor connected with each other. The liquid crystal capacitor is composed of a pixel electrode connected to the TFT, and a common electrode facing the pixel electrode and the liquid crystal between them. The TFT supplies the data signal from the first data line 136 to the pixel electrode in response to the output pulse from the first gate line 140. The liquid crystal capacitor charges the difference voltage between the data signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of liquid crystal molecules according to the difference voltage.

In addition, the second display panel 128 includes a second gate line 142 and a second data line 142 in which some of the first data lines 136 of the first display panel 124 are shared.

The drivers 30, 32, and 34 may drive the first and second gate drivers 32 and 34 to drive the gate lines 140 and the data driver 30 to drive the first and second data lines 36 and 38. It includes.

Therefore, the data driver 30 converts the digital data signal into an image signal and supplies it to the second data line 38 connected to the first data line 36 and the conductive film 26. At the same time, the first gate driver 32 sequentially supplies a gate signal to the first gate line 40.

Here, the first gate driver 32 transfers the gate signal to the second gate driver 34 using the gate connection signal line formed on the conductive film 26. The second gate driver 34 receiving the gate signal supplies the gate signal to the second gate line 42. Here, the second gate line 42 to which the gate signal is supplied and the second data line 38 to which the data signal is supplied respectively implement an image corresponding to the supplied signal.

In the liquid crystal display device driven in this manner, the first data line 36 is connected to the second data line 38 of the second flat panel display device 28.

However, as the data lines of the "B" region are driven with longer lengths than the data lines of the "A" region and the "C" region, they are implemented in the image and the "B" region implemented in the "A" region and the "C" region. The image to be expressed will be different quality.

Specifically, since the data line of the "B" region is formed longer than the data lines of the "A" region and the "C" region, the voltage drop of the signal supplied to the data line of the "B" region by line resistance or the like is " It becomes larger than the voltage drop of the signal supplied to the data lines in the areas A "and" B ".

Therefore, when the level of the image signal supplied from the data driver 30 is equally supplied to the "A", "B", and "C" areas, the image of the "B" area is the same as the "A" and "C" areas. Problems appearing darker than the image occurs.

The present invention is to solve the above problems, and to provide a dual display device and a driving method thereof that can improve the image quality uniformity.

According to an aspect of the present invention, there is provided a dual display device including a first display panel including pixel cells formed in regions defined by first data lines and first gate lines; A second display panel including pixel cells formed in regions defined by second data lines and second gate lines; A panel driver which drives the first and second display panels; A controller for controlling the panel driver; And a switching unit for selectively connecting the first display panel to the second display panel by the controller.

A driving method of a dual display device according to an exemplary embodiment of the present invention includes a first display panel, a second data line, and a second display panel including pixel cells formed in regions defined by first data lines and first gate lines. A driving method of a dual display device including a second display panel including a pixel cell formed in each region defined by gate lines, the method comprising: a switching signal for selectively connecting the first display panel to the second display panel Generating a; Interrupting electrical connection between the first display panel and the second display panel according to the switching signal; And displaying an image on the first display panel.

The driving method may include electrically connecting the first display panel and the second display panel according to the switching signal; And displaying an image on the second display panel.

Hereinafter, with reference to the accompanying drawings and embodiments will be described in detail the present invention.

FIG. 2 is a diagram illustrating a dual display device according to an exemplary embodiment of the present invention, and FIG. 3 is a diagram illustrating the switching unit illustrated in FIG. 2.

2 and 3, a dual display device according to an embodiment of the present invention includes a first display panel including pixel cells formed in regions defined by first data lines 136 and first gate lines 140. 124); A second display panel 128 including pixel cells formed in regions defined by the second data lines 138 and the second gate lines 142; A conductive film 126 electrically connecting the first data line 136 and the second data line 142; Panel drivers (130,132,134) for driving the first and second display panels (124, 128); A controller 120 for controlling the panel driver 130, 132, 134; And a switching unit 144 selectively connecting the first display panel 124 to the second display panel 128 by the controller 120.

The first display panel 124 is connected to a TFT and a thin film transistor (TFT) formed in each pixel area defined by the plurality of first gate lines 140 and the plurality of first data lines 136. And a liquid crystal capacitor Clc. The liquid crystal capacitor Clc is composed of a pixel electrode connected to a TFT and a common electrode facing each other with the pixel electrode and the liquid crystal interposed therebetween. The TFT supplies the data signal from the first data line 136 to the pixel electrode in response to the output pulse from the first gate line 140. The liquid crystal capacitor Clc charges the difference voltage between the data signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of liquid crystal molecules according to the difference voltage. The storage capacitors are connected in parallel to the liquid crystal capacitor Clc to maintain the voltage charged in the liquid crystal capacitor Clc until the next data signal is supplied. The storage capacitor Cst is formed by overlapping the pixel electrode with the previous gate line and the insulating layer interposed therebetween. In contrast, the storage capacitor Cst is formed by overlapping the pixel electrode with the storage line and the insulating layer interposed therebetween.

In addition, the second display panel 128 includes a second gate line 142 and a second data line 142 in which some of the first data lines 136 of the first display panel 124 are shared. The second display panel 128 may include a switching unit 144 in a non-pixel area in which some of the first data lines 136 are connected to the second data lines 142 which are shared. 1 has the same configuration as the display panel 124.

The panel drivers 130, 132, and 134 drive the first display panel 124 and the second display panel 128 to drive the first gate driver 132 to drive the first gate lines 140 of the first display panel 124. ), A second gate driver 142 for driving the second gate lines 142 of the second display panel 128, and a data driver for driving the first data line 136 and the second data line 138. It comprises 130.

The first and second gate drivers 132 and 134 may include a gate control signal from the timing controller 146, for example, a gate start signal (GSP), a gate shift clock (GSC), and a gate output signal. The scan pulse is supplied to each gate line using a gate output enable (GOE) signal. In other words, the gate drivers 132 and 134 sequentially shift the GSP from the timing controller 146 according to the GSC to sequentially supply the gate high voltage scan pulses to the gate lines. The gate low voltage is supplied when the scan pulse is not supplied to the gate lines. Here, the first and second gate drivers 132 and 134 control the pulse width of the scan pulse according to the GOE signal.

The data driver 130 may include data control signals from the timing controller 146, for example, a source start signal (SSP), a source shift clock (SSC), and a source output enable (SOE) source. Output Enable) signal is used to supply analog video signal to the data line.

In other words, the data driver 130 latches the digital image data input according to the source shift clock SSC, and outputs the data in line units in response to the source output enable signal. In this case, the data driver 130 converts digital image data in a line unit into an analog image signal and outputs the analog image signal. In detail, the data driver 130 converts digital image data in a line unit into an analog image signal using a gamma voltage from a gamma voltage unit (not shown) and outputs the analog image signal as data lines.

The conductive film 126 electrically connects a portion of the first data line 136 of the first display panel 124 and the second data line 138 of the second display panel 128. Accordingly, some of the data signals supplied to the first data line 136 of the first display panel 124 are equally supplied to the second data line 138 of the second display panel 128. That is, the data signal is supplied to the second data line 138 connected to the first data line 136. The gate signals supplied to the first gate driver 132 may be equally supplied to the second gate driver 134 using a gate connection signal line formed on the conductive film 126. Here, the FPC (Flexible Printed Circuit) is used as the conductive film.

The control unit 120 transmits a switching signal to the switching unit 144 that operates the panel drivers 130, 132, 134 and selectively connects the first and second display panels 124, 128 to the part of the first data lines 136. The second data line 138 is selectively connected and controlled. The controller 120 controls the timing controller 146 and the timing controller 146 for supplying control signals for controlling the first and second gate drivers 132 and 134 and the data driver 130 to the liquid crystal display. It may also include a power supply unit 148 for supplying various driving voltages used.

The timing controller 146 controls driving timings of the first and second gate drivers 132 and 134 and the data driver 130, and supplies a pixel data signal to the data driver 130.

The power supply unit 148 may change the input voltage from the outside into a DC driving voltage or an AC driving voltage and output the same. In other words, the power supply unit 148 generates a plurality of driving voltages required for driving the liquid crystal display using an input voltage, for example, a gate high voltage, a gate low voltage, and an analog driving voltage to generate the first and second gate drivers. 132 and 134, the data driver 130, the timing controller 146, and the like.

As illustrated in FIG. 3, the switching unit 144 is formed on the second display panel 128 so that the first switch panel 144 may have the first display panel 124 according to the switching control signal CS from the timing controller 146. The data line 136 and the second data lines 138 of the second display panel 128 are selectively connected. In this case, as illustrated in FIG. 4, the switching unit 144 is formed under the first display panel 124 so that the switching unit 144 of the first display panel 124 may be formed according to the switching control signal CS from the timing controller 146. The first data line 136 and the second data lines 138 of the second display panel 128 may be selectively connected. Hereinafter, it is assumed that the switching unit 144 is formed on the second display panel 128.

The switching unit 144 includes a plurality of on / off switching elements connected between the first data line 136 of the first display panel 124 and the second data lines 138 of the second display panel 128. S1 to Sn). In this case, each of the on / off switching elements S1 to Sn may be a P-type or N-type thin film transistor.

Each of the on / off switching elements S1 to Sn may include a control electrode supplied with the switching control signal CS from the timing controller 146 and a first electrode of the first display panel 124 through the conductive film 126. And a source electrode connected to the data line 136 and a drain electrode connected to the second data line 138.

Each of the on / off switching elements S1 to Sn may be connected to some of the first data lines 136 of the first display panel 124 according to the switching control signal CS from the timing controller 146. The second data line 138 of the second display panel 128 is electrically connected.

Specifically, in the case of displaying an image on the first display panel 124, the timing controller 146 generates a switching control signal CS in a low state and supplies it to the switching unit 144. Accordingly, each of the on / off switching elements S1 to Sn of the switching unit 144 is turned off according to the switching control signal CS in the low state, thereby the first data line 136 of the first display panel 124. The connection between the second data line 138 and the second display panel 128 is blocked.

On the other hand, in the case of displaying an image on the second display panel 128, the timing controller 146 generates a switching control signal CS in a high state and supplies it to the switching unit 144. Accordingly, each of the on / off switching elements S1 to Sn of the switching unit 144 is turned on in response to the switching control signal CS in the high state, so that the first data line 136 of the first display panel 124 is turned on. Some of the plurality of terminals 1) and the second data line 138 of the second display panel 128 are electrically connected to each other.

As described above, the present invention selectively connects the first display panel 124 and the second display panel 128 by using the switching unit 144 to reduce the line load of the panel to compensate the charging characteristics to improve the uniformity of the image quality. In addition, the first and second display panels 124 and 128 may be driven without increasing the driving capability of the panel drivers 130, 132, and 134.

Although the wiring of the data line has been described as an example in the present embodiment, the present invention can be applied to a gate line when the data line is shared to the first display panel 124 and the second display panel 128.

Meanwhile, in the dual display device of the present invention, the pixel cell described above is a liquid crystal cell displaying an image by adjusting light transmittance, but the present invention is not limited thereto and may be a light emitting cell displaying an image according to the amount of current applied thereto. have.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

The dual display device and the driving method thereof according to the present invention reduce the line load of the panel by selectively connecting the first display panel and the second display panel by using a switching unit, thereby compensating charging characteristics to increase the uniformity of the image quality and the panel. The first and second display panels can be driven without increasing the driving capability of the driver.

Claims (9)

A first display panel including pixel cells formed in regions defined by first data lines and first gate lines; A second display panel including pixel cells formed in regions defined by second data lines and second gate lines; A panel driver which drives the first and second display panels; A controller for controlling the panel driver; And And a switching unit configured to selectively connect the first display panel to the second display panel by the control unit. The method of claim 1, And the switching unit selectively connects some of the first data lines and the second data line. The method of claim 2, The control unit, Supplies a data signal to the panel driver and generates a control signal for controlling the panel driver; And a switching signal for selectively connecting some of the first data lines of the first display panel to the second data line. The method of claim 3, wherein And the switching unit includes a plurality of switching elements controlled by the switching signal and connected between some of the first data lines and the second data line. The method of claim 1, And the switching unit is disposed below the first display panel adjacent to the second display panel or above the second display panel adjacent to the first display panel. The method of claim 3, wherein The panel driver; A data driver disposed on the first display panel so as to be connected to first data lines of the first display panel, and supplying an image signal to the first data lines under control of the controller; A first gate driver disposed on the first display panel to be connected to the first gate lines of the first display panel and supplying a gate signal to the first gate lines in response to the control of the controller; And And a second gate driver disposed on the second display panel to be connected to the second gate lines of the second display panel and supplying a gate signal to the second gate lines in response to the control of the controller. Dual display device characterized in that. The method of claim 1, And the pixel cell is a liquid crystal cell displaying an image by adjusting light transmittance, or a light emitting cell displaying an image by emitting light according to an amount of current. A first display panel including pixel cells formed in regions defined by first data lines and first gate lines, and pixel cells formed in regions defined by second data lines and second gate lines. In a driving method of a dual display device comprising a second display panel, Generating a switching signal for selectively connecting the first display panel to the second display panel; Interrupting electrical connection between the first display panel and the second display panel according to the switching signal; And displaying an image on the first display panel. The method of claim 8, Electrically connecting the first display panel and the second display panel according to the switching signal; And And displaying an image on the second display panel.

Images