KR20090000949A

KR20090000949A - Display apparatus

Info

Publication number: KR20090000949A
Application number: KR1020070064911A
Authority: KR
Inventors: 김범준; 채종석
Original assignee: 삼성전자주식회사
Priority date: 2007-06-29
Filing date: 2007-06-29
Publication date: 2009-01-08

Abstract

The display device capable of improving the compatibility of the driving IC includes a display panel, a driving IC, and a voltage changer. The display panel displays an image to the outside, and the driving IC is electrically connected to the display panel to generate a driving signal for controlling the display panel. The voltage changer is electrically connected to the driving IC and controls the driving IC to generate a driving signal corresponding to the material characteristic of the display panel. In this way, by controlling the driving IC so that the voltage changing unit corresponds to the material characteristic of the display panel, the compatibility of the driving IC which is already set to match the other material characteristic of the display panel can be further improved.

Description

Display device {DISPLAY APPARATUS}

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present invention.

FIG. 2 is a waveform diagram comparing a gate signal of an amorphous silicon (a-Si) display panel with a gate signal of a polysilicon (poly-Si) display panel.

FIG. 3 is a circuit diagram illustrating an electrical connection relationship between a driving IC and a voltage changer for generating a gate signal in a display panel of poly-Si in FIG. 1.

4 is a waveform diagram comparing a common voltage in a display panel of amorphous silicon (a-Si) with a common voltage in a display panel of polysilicon (poly-Si).

FIG. 5 is a circuit diagram illustrating an electrical connection relationship between a driving IC and a voltage changer for generating a common voltage in a display panel of poly-Si in FIG. 1.

100: timing controller 200: drive IC

DS: data signal GS: gate signal

Vcom: Common Voltage Vst: Storage Voltage

300: voltage change unit VGH: gate high voltage

VGL: Gate Low Voltage VcomH: High Common Voltage

VcomL: Low Common Voltage 400: Display Panel

TFT: thin film transistor

The present invention relates to a display device, and more particularly, to a display device for displaying an image using light transmittance of liquid crystals.

A liquid crystal display is a flat panel display that displays an image by using a change in light transmittance of a liquid crystal. The liquid crystal display includes a backlight assembly for generating light, a liquid crystal display panel receiving the light from the backlight assembly to display an image, and a driving IC for driving the liquid crystal display panel.

The liquid crystal display panel includes a first substrate having a thin film transistor, a second substrate having a common electrode, and a liquid crystal layer interposed between the first and second substrates. In this case, the driving IC controls the thin film transistor by applying a gate signal and a data signal to the first substrate, and applies a common voltage to the common electrode. On the other hand, the first substrate is generally made of amorphous silicon (a-Si) as a substrate. That is, the channel layer of the thin film transistor includes amorphous silicon (a-Si).

As described above, when the first substrate is an amorphous silicon substrate made of amorphous silicon (a-Si), the gate signal and the common voltage should have a value corresponding to that of the amorphous silicon substrate. That is, the driving IC should generate the gate signal and the common voltage corresponding to the amorphous silicon substrate.

However, the first substrate may be a polysilicon substrate made of poly-Si rather than amorphous silicon. When the first substrate is the polysilicon substrate, a problem may occur in that the driving IC for the amorphous silicon substrate cannot be used for the polysilicon substrate.

Accordingly, an object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a display device capable of improving compatibility of a driving IC.

According to an exemplary embodiment of the present invention, a display device includes a display panel, a driving IC, and a voltage changer.

The display panel displays an image to the outside. The driving IC is electrically connected to the display panel to generate a driving signal for controlling the display panel. The voltage changer is electrically connected to the driving IC and controls the driving IC to generate the driving signal corresponding to the material characteristic of the display panel.

The display panel may include a first substrate, a second substrate, and a liquid crystal layer. In detail, the first substrate may include a gate wiring formed in a first direction, a data wiring formed in a second direction crossing the first direction, a thin film transistor electrically connected to the gate and the data wire, and a thin film transistor electrically connected to the thin film transistor. The pixel substrate includes a common electrode formed on the front surface of the substrate, and the liquid crystal layer is interposed between the first and second substrates.

Meanwhile, the first substrate is a polysilicon substrate including polysilicon (poly-Si), and the driving IC is a driving IC for amorphous silicon set to drive an amorphous silicon substrate including amorphous silicon (a-Si). The voltage changer may control the amorphous silicon driving IC to drive the polysilicon substrate.

The voltage changer may control the driving IC to apply a gate signal corresponding to a material characteristic of the display panel to the gate wiring, but apply the common voltage corresponding to a material characteristic of the display panel to the common electrode. The drive IC can also be controlled.

The voltage changer may apply a second control voltage to the driving IC in response to the first control voltage applied from the driving IC. Preferably, the second control voltage has a lower level than the first control voltage. In detail, the voltage changer may include a plurality of string resistors to lower the first control voltage to the second control voltage.

The voltage change unit may be formed on the first substrate or on a separate flexible circuit board electrically connected to the first substrate.

According to the present invention, by controlling the driving IC so that the voltage changing section corresponds to the material characteristic of the display panel, the compatibility of the driving IC which is already set for other material characteristics of the display panel can be further improved.

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

Referring to FIG. 1, the display device according to the present exemplary embodiment includes a timing controller 100, a driving IC 200, a voltage changing unit 300, and a display panel 400.

First, the display panel 400 will be described in brief. The display panel 400 may include a first substrate, a second substrate, and a liquid crystal layer to display an image to the outside.

The first substrate is a thin film transistor electrically connected to a gate line GL formed in a first direction, a data line DL formed in a second direction crossing the first direction, and the gate and data lines GL and DL. And a pixel electrode (not shown) electrically connected to the thin film transistor TFT.

In this case, the first substrate may further include a storage line (not shown) formed along the first direction and overlapping the pixel electrode. As the storage line and the pixel electrode overlap each other, a storage capacitor Cst can be formed.

In addition, a gate signal GS is applied to the gate line GL, a data signal DS is applied to the data line DL, and a storage voltage Vst is applied to the storage line GL.

The second substrate is disposed to face the first substrate. The second substrate may include a common electrode formed on the front surface of the substrate and a color filter formed to correspond to the pixel electrode. As the common electrode and the pixel electrode are spaced apart from each other and disposed to face each other, the liquid crystal capacitor Clc may be formed. In this case, a common voltage Vcom is applied to the common electrode.

The liquid crystal layer is interposed between the first substrate and the second substrate. The liquid crystal layer may change an arrangement of liquid crystals by a voltage applied between the first substrate and the second substrate, that is, a voltage applied between the common electrode and the pixel electrode. When the arrangement of the liquid crystals is changed, the light transmittance of the liquid crystals may be changed.

On the other hand, the first substrate is mostly a silicon substrate containing silicon (Si). In this case, the silicon (Si) may be classified into amorphous silicon (a-Si) having an amorphous structure and polysilicon (poly-Si) having a crystal structure. That is, the first substrate may be an amorphous silicon substrate including amorphous silicon (a-Si), or may be a polysilicon substrate including poly-Si.

When the first substrate is the amorphous silicon substrate, the channel layer of the thin film transistor TFT of the first substrate is formed of amorphous silicon (a-Si). On the other hand, when the first substrate is the polysilicon substrate, the channel layer of the thin film transistor TFT of the first substrate may be made of poly-Si.

On the other hand, the first substrate may have different characteristics when the amorphous silicon substrate and the polysilicon substrate. For example, characteristics of the thin film transistor TFT and the liquid crystal capacitor Clc may vary according to material characteristics of the first substrate. Therefore, the gate signal GS applied to the gate wiring GL and the common voltage Vcom applied to the common electrode may also have different levels of voltages according to material properties of the first substrate. .

Subsequently, the driving IC 200 is electrically connected to the display panel 400 to generate a driving signal for controlling the display panel 400. For example, the driving signal may include the gate signal GS applied to the gate line GL, the data signal DS applied to the data line DL, and the storage voltage applied to the storage line. Vst) and the common voltage Vcom applied to the common electrode.

The driving IC 200 may be disposed on the first substrate and electrically connected to the first substrate. That is, the driving IC 200 may be electrically connected to the pad portion formed on the first substrate.

The voltage change unit 300 is electrically connected to the driving IC 200 and generates a material characteristic of the display panel 400, that is, a driving signal corresponding to the amorphous silicon substrate and the polysilicon substrate. The driving IC 200 is controlled.

Specifically, for example, if the first substrate is the polysilicon substrate, and the driving IC 200 is an amorphous silicon driving IC set to drive the amorphous silicon substrate, the voltage change unit 300 is The amorphous silicon driving IC may be controlled to generate a driving signal capable of driving the polysilicon substrate.

On the other hand, if the first substrate is the amorphous silicon substrate, and the driver IC 200 is a polysilicon driving IC set for driving the polysilicon substrate, the voltage changing unit 300 is for the polysilicon. The driving IC for the polysilicon may be controlled to generate a driving signal for driving the amorphous silicon substrate.

More specifically, for example, the voltage changer 300 applies the driving IC 200 to apply different gate signals GS to the gate wiring GL according to the amorphous silicon substrate and the polysilicon substrate. Can be controlled. Alternatively, the voltage changer 300 may control the driving IC 200 to apply different common voltages Vcom to the common electrode according to the amorphous silicon substrate and the polysilicon substrate.

The voltage changer 200 may apply a voltage change output signal VO to the drive IC 200 in response to the voltage change input signal VI applied from the drive IC 200.

Here, if the first substrate is the amorphous silicon substrate, and the driving IC 200 is a driving IC for polysilicon set to drive the polysilicon substrate, the voltage change output signal VO is the voltage change. It is desirable to have a voltage at a level lower than that of the input signal VI. On the other hand, if the first substrate is the amorphous silicon substrate and the driving IC 200 is a driving IC for polysilicon set to drive the polysilicon substrate, the voltage change output signal VO is the voltage change. It is desirable to have a voltage level higher than that of the input signal VI.

For example, in order for the voltage change output signal VO to have a voltage at a level lower than that of the voltage change input signal VI, the voltage change unit 200 changes the voltage change input signal VI to the voltage change. A plurality of string resistors may be included to lower the output signal VO. A more detailed description will be described later using separate drawings.

Finally, the timing controller 100 may be electrically connected to the driving IC 200 to control the driving IC 200. That is, the timing controller 100 may generate a driving control signal CON for controlling the driving IC 200 in response to an image control signal applied from the outside.

Meanwhile, the voltage changer 200 may be formed on the first substrate. Alternatively, when the display device according to the present embodiment further includes a separate flexible circuit board electrically connected to the first substrate, the voltage change unit 200 may be formed on the flexible circuit board.

FIG. 2 is a waveform diagram comparing a gate signal of an amorphous silicon (a-Si) display panel with a gate signal of a polysilicon (poly-Si) display panel, and FIG. 3 is a polysilicon layer of FIG. 1. A circuit diagram showing an electrical connection relationship between a driving IC and a voltage changer for generating a gate signal in a display panel of Si).

2 and 3, a process of outputting a gate signal GS corresponding to a material characteristic of the first substrate will be described briefly.

First, the gate signal GS is formed by the gate high voltage VGH and the gate low voltage VGL. The gate high voltage VGH and the gate low voltage VGL may have different values when the first substrate is the amorphous silicon substrate and the polysilicon substrate.

In general, the difference between the gate high voltage VGH and the gate low voltage VGL is greater in the amorphous silicon substrate than in the polysilicon substrate. For example, when the first substrate is the amorphous silicon substrate, the gate high voltage VGH is about 15 V and the gate low voltage VGL is −9 V, and the first substrate is the polysilicon substrate. In this case, the gate high voltage VGH may be about 9 V and the gate low voltage VGL may be −7 V.

Therefore, when the driving IC 200 is set to generate the gate signal GS corresponding to the amorphous silicon substrate, the driving IC 200 generates the gate signal GS corresponding to the polysilicon substrate. It is necessary to control the drive IC 200 to make. In the present embodiment, the voltage changer 200 may perform a function of controlling the driving IC 200.

Referring to FIG. 3, the voltage changer 300 may include a plurality of voltage divider resistors and a selection wiring 310. For example, the voltage distribution resistors may include a first resistor R1, a second resistor R2, and a third resistor R3 connected in series.

The first to third resistors R1, R2, and R3 connected in series are electrically connected to the A1 terminal and the ground of the driving IC 200. When a first control voltage is output through the A1 terminal, different voltages are applied at the first to third points P1, P2, and P3 corresponding to one ends of the first to third resistors R1, R2, and R3. Can be formed. A voltage equal to the first control voltage is formed at the first point P1, a voltage lower than the first control voltage is formed at the second point P2, and at the third point P3, the voltage equal to the first control voltage is formed. A voltage lower than one control voltage is formed.

The selection wiring 310 may apply any one of voltages formed at each of the first and third points P1, P2, and P3 to the A2 terminal of the driving IC 200. That is, the selection wiring 310 may be any one of the first and third points P1, P2, and P3 and the driving according to the material characteristics of the first substrate and the setting characteristics of the driving IC 200. It may be electrically connected to the A2 terminal of the IC 200.

The driving IC 200 may include a gate reference voltage generator 210 and a gate driver 220. Here, when the voltage applied to the A2 terminal of the driving IC 200 through the selection wiring 310 is called a second control voltage, the second control voltage is applied to the gate reference voltage generator 210. . The gate reference voltage generator 210 may output the gate high voltage VGH and the gate low voltage VGL to the gate driver 220 in response to the second control voltage. That is, the gate reference voltage generator 210 may control the gate high voltage VGH and the gate low voltage VGL having different values according to the material characteristics of the first substrate and the setting characteristics of the driving IC 200. You can print The gate driver 220 may apply the gate high voltage VGH and the gate low voltage VGL to apply the gate signal GS to the gate line GL.

4 is a waveform diagram comparing a common voltage of a display panel of amorphous silicon (a-Si) with a common voltage of a display panel of poly-Si. FIG. 5 is a diagram illustrating poly-poly (poly-) of FIG. 1. A circuit diagram showing an electrical connection relationship between a driving IC and a voltage changer for generating a common voltage in a display panel of Si).

4 and 5, a process of outputting the common voltage Vcom corresponding to the material characteristic of the first substrate will be described briefly.

First, the common voltage Vcom is formed by the high common voltage VcomH and the low common voltage VcomL. The high common voltage VcomH and the low common voltage VcomL may have different values when the first substrate is the amorphous silicon substrate and when the first silicon substrate is the polysilicon substrate. In general, the difference between the high common voltage VcomH and the low common voltage VcomL is greater in the amorphous silicon substrate than in the polysilicon substrate.

Therefore, when the driving IC 200 is set to generate a common voltage Vcom corresponding to the amorphous silicon substrate, the driving IC 200 generates a common voltage Vom corresponding to the polysilicon substrate. It is necessary to control the drive IC 200 to make. In the present embodiment, the voltage changer 200 may perform a function of controlling the driving IC 200.

Referring to FIG. 5, the voltage changer 300 may include a plurality of voltage distribution resistors, and may further include a plurality of capacitors.

For example, the voltage divider resistors may have a high divider resistor having first and second high resistors RH1 and RH2 connected in series and a low divider resistor having first and second low resistors RL1 and RL2 connected in series. In an exemplary embodiment, the capacitors may include first to third capacitors C1, C2, and C3.

Both ends of the first and second high resistors RH1 and RH2 connected in series are electrically connected to the GVDD terminal and the B1 terminal of the driving IC 200, respectively. The point between the first and second high resistors RH1 and RH2 is electrically connected to the B2 terminal of the driving IC 200.

In addition, both ends of the first and second low resistances RL1 and RL2 connected in series are electrically connected to the GVDD terminal and the C1 terminal of the driving IC 200, respectively. The point between the first and second low resistors RL1 and RL2 is electrically connected to the C2 terminal of the driving IC 200.

Meanwhile, both ends of the first capacitor C1 are electrically connected to the GVDD terminal and the ground of the driving IC 200, and both ends of the second capacitor C2 are connected to the first and second high resistors RH1,. It is electrically connected to the ground and the point between RH2, both ends of the third capacitor (C3) is electrically connected to the ground and the point between the first and second low resistance (RL1, RL2).

A driving reference voltage is formed at the GVDD terminal of the driving IC 200, a first high voltage is formed at the B1 terminal of the driving IC 200, and a first low voltage is formed at the C1 terminal of the driving IC 200. When formed, a second high voltage is formed at the B2 terminal of the driving IC 200, and a second low voltage is formed at the C2 terminal of the driving IC 200.

That is, the first high voltage emitted from the B1 terminal of the driving IC 200 is applied to the high distribution resistor part to receive the second high voltage at a point between the first and second high resistors RH1 and RH2. And the second high voltage thus formed is applied to the B2 terminal of the driving IC 200. In addition, the first low voltage emitted from the C1 terminal of the driving IC 200 is applied to the low distribution resistor part to receive the second low voltage at a point between the first and second low resistors RL1 and RL2. The second low voltage may be applied to the C2 terminal of the driving IC 200.

As a result, the second high voltage may have a lower voltage than the first high voltage, and the second low voltage may have a lower voltage than the first low voltage. The second high voltage and the second low voltage are the high common voltage VcomH and the low common voltage VcomL for forming the common voltage Vcom.

The driving IC 200 may include a common voltage generator 230. The second high voltage applied to the B2 terminal of the driving IC 200, that is, the high common voltage VcomH, is applied to the common voltage generator 230 and applied to the C2 terminal of the driving IC 200. The second low voltage, that is, the low common voltage VcomL, is also applied to the common voltage generator 230. The common voltage generator 230 outputs the common voltage Vcom to the common electrode in response to the high common voltage VcomH and the low common voltage VcomL.

As described above, when the driving IC 200 is set to output a driving signal for driving the amorphous silicon substrate, the voltage changing unit 300 causes the driving IC 200 to transmit the amorphous signal. The driving IC 200 may be controlled to be output by changing to a driving signal for driving the polysilicon substrate instead of the silicon substrate. Therefore, compatibility of the driving IC 200 may be further improved without adding a program for changing the setting of the driving IC 200 or changing H / W in the driving IC 200.

According to the present invention, as the display device includes a voltage changer capable of controlling the driving IC so as to correspond to the material characteristics of the display panel, the compatibility of the driving ICs already set to match the other material characteristics of the display panel can be achieved. It can improve more. On the other hand, as the compatibility of the driving IC is further increased, the manufacturing cost of the display device may be further reduced.

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge in the scope of the invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims

A display panel for displaying an image;

A driving IC electrically connected to the display panel to generate a driving signal for controlling the display panel; And

And a voltage changer electrically connected to the driving IC and controlling the driving IC to generate the driving signal corresponding to material characteristics of the display panel.

The display panel of claim 1, wherein the display panel

A first substrate having a gate wiring formed in a first direction, a data wiring formed in a second direction crossing the first direction, a thin film transistor electrically connected to the gate and the data wiring, and a pixel electrode electrically connected to the thin film transistor;

A second substrate having a common electrode formed on an entire surface of the substrate; And

And a liquid crystal layer interposed between the first and second substrates.

The method of claim 2, wherein the first substrate is a polysilicon substrate including poly-Si,

The driving IC is a driving IC for amorphous silicon set to drive an amorphous silicon substrate including amorphous silicon (a-Si),

And the voltage changer controls the amorphous silicon driving IC to drive the polysilicon substrate.

The method of claim 2, wherein the voltage changer

And controlling the driving IC to apply a gate signal corresponding to a material characteristic of the display panel to the gate wiring.

The method of claim 2, wherein the voltage changer

And controlling the driving IC to apply a common voltage corresponding to a material characteristic of the display panel to the common electrode.

The method of claim 2, wherein the voltage changer

And a second control voltage is applied to the driving IC in response to the first control voltage applied from the driving IC.

The display device of claim 6, wherein the second control voltage has a lower level than the first control voltage.

The method of claim 7, wherein the voltage changer

And a plurality of string resistors for lowering the first control voltage to the second control voltage.

The display device of claim 2, wherein the voltage changer is formed on the first substrate.

The method of claim 2, further comprising a flexible circuit board electrically connected to the first substrate,

And the voltage changer is formed on the flexible circuit board.