KR20040090297A - Liquid crystal display panel - Google Patents

Abstract

PURPOSE: An LCD(Liquid Crystal Display) panel is provided to equally maintain loads loaded in data lines by uniformly maintaining the number of TFTs(Thin Film Transistors) combined with the data lines. CONSTITUTION: A pixel part(PP) has a gate line, a data line, the first TFT(T1) connected to the gate line and the data line, and a pixel electrode connected to the first TFT. A light sensing part(LSP) has the first sensor line(SL1), the second TFT(T2), the third TFT(T3) and the second sensor line(SL2). The first sensor line receives the first signal from a control unit to control the driving of the pixel part. The second TFT(T2) outputs the first signal provided through the first sensor line in response to light provided from the outside. The third TFT(T3) outputs the first signal provided from the second TFT in response to the second signal provided through the gate line. The second sensor line provides the first signal outputted from the third TFT to the control unit.

Description

Liquid Crystal Display Panel {LIQUID CRYSTAL DISPLAY PANEL}

The present invention relates to a liquid crystal display panel, and more particularly, to a liquid crystal display panel that can improve display characteristics.

In general, the touch panel is provided on the top of the display device to directly contact the hand and the object so that the instruction content displayed on the screen of the display device can be selected by a human hand or an object. The touch panel detects the touched position and receives the content indicated by the touched position as an input signal to drive the display device. Since the touch panel image display device does not require a separate input device connected to the display device such as a keyboard and a mouse, its use is increasing.

Recently, the touch panel has been used in a liquid crystal display device. The touch panel liquid crystal display device includes a liquid crystal display panel for displaying an image and a touch provided on an upper side of the liquid crystal display panel to detect position information by receiving a predetermined input from a user. Includes a panel.

The touch panel includes a first substrate, a second substrate spaced apart from the first substrate by a predetermined distance, and first and second transparent electrodes formed on surfaces of the first and second substrates facing each other.

The touch panel liquid crystal display uses a frame or an adhesive that creates an air layer between the liquid crystal display panel and the touch panel. Accordingly, a layer having a different refractive index is formed between the liquid crystal display panel and the touch panel, thereby degrading the overall optical characteristics of the touch panel liquid crystal display device.

In addition, since the first and second transparent electrodes and the first and second substrates provided in the touch panel must be provided, manufacturing costs are increased and the overall thickness of the touch panel liquid crystal display device is also increased.

It is therefore an object of the present invention to provide a liquid crystal display panel for improving display characteristics.

1 is a block diagram of a liquid crystal display device having a liquid crystal display panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the liquid crystal display panel shown in FIG. 1.

3 is an enlarged cross-sectional view of the liquid crystal display panel illustrated in FIG. 2.

4 and 5 are plan views illustrating the array substrate illustrated in FIG. 3 in detail.

6 is an equivalent circuit diagram of each pixel and the light sensing unit of the array substrate illustrated in FIG. 4.

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

100: array substrate 400: liquid crystal display panel

500: reading part 600: driving part

700: liquid crystal display device LSP: light detector

PP: pixel portion SL1: first sensor line

SL2: second sensor line T1: first TFT

T2: second TFT T3: third TFT

The liquid crystal display panel according to the present invention for achieving the above object is to detect a pixel portion for displaying an image and a position provided with light from the outside and to provide the detected position information to a controller for controlling the driving of the pixel portion. It includes a light sensing unit.

The pixel unit includes a gate line, a data line, a first switching element connected to the gate line and the data line, and a pixel electrode connected to the first switching element, and the light sensing unit includes a first sensor line, a second switching element, and a first switching element. It consists of three switching elements and a second sensor line.

The first sensor line is connected to the control unit and receives a first signal. The second switching element outputs the first signal provided from the first sensor line in response to the light. The third switching device outputs the first signal applied from the second switching device in response to a second signal provided from the gate line. The second sensor line provides the first signal output from the third switching device to the controller.

According to the liquid crystal display panel, the second switching element of the light sensing unit outputs a first signal provided through the first sensor line in response to light, and the third switching element is formed in response to a second signal provided through the gate line. 2 outputs the first signal applied from the switching element to the second sensor line. Therefore, display characteristics of the liquid crystal display panel can be improved.

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

1 is a block diagram of a liquid crystal display device having a liquid crystal display panel according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the liquid crystal display panel shown in FIG.

1 and 2, a liquid crystal display device 700 having a liquid crystal display panel 400 according to an embodiment of the present invention includes a liquid crystal display panel 400, a light sensing unit LSP, and a controller. . The liquid crystal display panel 400 implements a display surface for displaying an image and receives light provided by a user through the display surface. The light detector 500 is embedded in the liquid crystal display panel 400 to sense the light incident through the display surface of the liquid crystal display panel 400.

The control unit includes a reading unit 500 and a driving unit 600. The reader 500 controls the driving of the light detector LSP so that the light detector LSP may sense the light in response to a control signal provided from the driver 600. In addition, the analog signal input from the light sensor LSP is converted into a digital signal, and the converted digital signal is transmitted to the driver 600.

The driver 600 provides the control signal for controlling the driving of the reader 500 to the reader 500, and in response to the digital signal input from the reader 500, the liquid crystal display. A driving signal for driving the panel 400 is output.

Thus, the liquid crystal display panel 400 displays an image in response to the driving signal. That is, the liquid crystal display 700 may display instructions corresponding to a position where the light is input on the current screen on a subsequent screen.

3 is an enlarged cross-sectional view of the liquid crystal display panel illustrated in FIG. 2, and FIGS. 4 and 5 are plan views illustrating the array substrate illustrated in FIG. 3 in detail.

2 and 3, the liquid crystal display panel 400 includes an array substrate 100, a color filter substrate 200 facing the array substrate 100, and the array substrate 100 and a color filter substrate 200. ) And a liquid crystal layer 300 interposed therebetween.

The array substrate 100 is a substrate having a plurality of pixel parts PP formed in a matrix form. In addition, the array substrate 100 includes a light detector LSP for sensing light input from the display surface 410 of the liquid crystal display panel 400 in a matrix form. Here, the ratio of the photo detector LSP to the entire area of the array substrate 100 is smaller than that of the pixel portion PP. Therefore, it is possible to reduce the decrease in the overall aperture ratio of the liquid crystal display panel 400 by the light sensing unit LSP.

Meanwhile, the light is provided by the user through the light pen 800 outside the liquid crystal display panel 400. The light pen 800 includes a light emitting diode (LED) for generating the light in a portion in contact with the display surface 410 of the liquid crystal display panel 400.

3 and 4, each of the plurality of pixel parts PP may include a gate line GL extending in a first direction D1, and a second direction perpendicular to the first direction D1. A first silicon line (Amorphous Silicon Thin Film Transistor) connected to the first data line DL1, the gate line GL, and the first data line DL1 respectively extending to D2) ) T1 and the transparent electrode TE and the reflective electrode RE connected to the first a-si TFT T1.

The first a-si TFT T1 may include a gate electrode branched from the gate line GL, a source electrode branched from the first data line DL1, and the transparent electrode TE and the reflective electrode RE. It is made of a drain electrode connected to. The first a-si TFT T1 receives an image signal applied to the first data line DL1 from the source electrode in response to a gate driving voltage applied to the gate line GL to the drain electrode. Output

Meanwhile, the light sensing unit LSP includes a second a-si TFT (T2) driven by light provided from the outside, and a third a-si TFT electrically connected to the second a-si TFT (T2). A first sensor line SL1 coupled to T3) and the third a-si TFT T3, extending in the second direction D2, extending in the first direction D1, The second sensor line SL2 receives the first signal.

The second a-si TFT T2 includes a gate electrode branched from the second sensor line SL1, a source electrode coupled to the gate electrode, and a drain electrode connected to the third a-si TFT T3. do. The gate electrode of the second a-si TFT (T2) and the source electrode are electrically connected to each other so that the first signal provided to the gate electrode is applied to the source electrode. That is, the first signal output from the read part is provided to the gate electrode through the second sensor line SL2 and then applied to the source electrode. Therefore, when the second a-si TFT (T2) is driven in response to light, the first signal is output to the drain electrode of the second a-si TFT (T2).

Here, the second sensor line SL2 is formed on the same layer as the gate line GL, and is electrically insulated from each other in a state spaced apart from the gate line GL at a predetermined interval.

The third a-si TFT T3 may include a gate electrode branched from the gate line GL, a source electrode connected to a drain electrode of the second a-si TFT T2, and a first sensor line SL1. Branched drain electrodes are provided. The first signal output from the drain electrode of the second a-si TFT (T2) is provided to the source electrode of the third a-si TFT (T3). The third a-si TFT (T3) when the third a-si TFT (T3) operates in response to a second signal which is the gate driving voltage provided to the gate line GL. Is output to the drain electrode. Thereafter, the first signal is input to the readout part through the first sensor line SL1 connected to the drain electrode of the third a-si TFT T3.

The first sensor line SL1 is formed on the same layer as the first data line DL1 and electrically insulated from the first data line DL1 at a predetermined interval.

As shown in FIG. 3, the density of the light sensing unit LSP in the liquid crystal display panel 400 is smaller than the density of each pixel unit PP, so that the light sensing unit LSP is the pixel unit. It is not provided corresponding to (PP). For example, the liquid crystal display panel 400 includes a plurality of light sensing units LSP, and the plurality of pixel units PP are disposed between the light sensing units LSP.

In this way, the source electrode of the second a-si TFT (T2) is not branched from the first data line DL1, but contacts with the gate electrode of the second a-si TFT (T2), thereby providing the first electrode. The load on the data line DL1 can be reduced. As a result, delay of the video signal can be prevented.

In addition, when the source electrode of the second a-si TFT (T2) is branched from the first data line DL1, the load and the light applied to the first data line DL1 to which the light sensing unit LSP is connected. A difference occurs in the load applied to the second data line DL2 to which the sensing unit LSP is not connected. Since the magnitude of the load between the first and second data lines DL1 and DL3 is different, crosstalk or flicker occurs in the liquid crystal display panel 400.

As such, when the source electrode of the second a-si TFT (T2) contacts the gate electrode of the second a-si TFT (T2), the source electrode may be caught between the first and second data lines DL1 and DL2. The load is the same, thereby improving the display characteristics of the liquid crystal display panel 400.

The transparent electrode TE is formed through a contact hole CON exposing a drain electrode of the first a-si TFT T1 on an insulating layer covering the first to third a-si TFTs T1 to T3. It is electrically connected to the first a-si TFT (T1). The transparent electrode TE is made of indium tin oxide (ITO) or indium zinc oxide (IZO), which is a transparent conductive material.

Meanwhile, the reflective electrode RE is formed on the transparent electrode TE and has an opening for exposing the transmission window W1 for exposing the transparent electrode TE and the second a-si TFT T2. The window W2 is provided. The reflective electrode RE may be formed of a single reflective film made of aluminum-neodymium (AlNd) having a high reflectance or a double reflective film made of aluminum-neodymium (Alnd) and tungsten molybdenum (MoW).

The transmission window W1 is generated by the liquid crystal display itself to form a transmission portion for transmitting first light incident from the rear surface of the liquid crystal display panel 400. In addition, the reflective electrode RE forms a reflecting part that reflects the second light when the second light provided from the outside of the liquid crystal display device is incident through the display surface of the liquid crystal display panel 400.

As shown in FIGS. 4 and 5, the opening window W2 is exposed to the second a-si TFT T2 and is intentionally provided by the user outside the liquid crystal display panel 400. It is easy to apply light to the second a-si TFT (T2). Here, the reflective electrode RE covers the first and third a-si TFTs T1 and T3 to prevent the first and third a-si TFTs T1 and T3 from reacting to the light. prevent.

The second a-si TFT T2 is manufactured to respond only to the light intentionally provided to the liquid crystal display panel 400 by using a light pen. That is, in addition to the light, the liquid crystal display panel 400 is provided with the first light generated by the liquid crystal display device itself and the second light such as sunlight. In this case, the light has a brightness higher than that of the first and second light, so that the second a-si TFT T2 can operate only on the light.

3 to 5 illustrate only a transflective liquid crystal display device including the transparent electrode TE and the reflective electrode RE. However, the present invention is not only applied to the transflective liquid crystal display device, but can also be sufficiently applied to a transmissive or reflective liquid crystal display device.

However, when the present invention is applied to the transmissive liquid crystal display, the transmissive liquid crystal display further includes a light blocking member for blocking the light from being incident on the first and third a-si TFTs T1 and T3. Equipped.

6 is an equivalent circuit diagram of a pixel unit and a light sensing unit of the array substrate illustrated in FIG. 4.

Referring to FIG. 6, each of the pixel units is connected to a drain line of a gate line GL, a first data line DL1, a first a-si TFT T1, and a first a-si TFT T1. (Clc). The light sensing unit includes a second a-si TFT (T2), a third a-si TFT (T3), and first and second sensor lines SL1 and SL2.

When the user uses a light pen to provide light through the display surface of the liquid crystal display panel to the light sensing unit built in the liquid crystal display panel, the second a-si TFT T2 is driven in response to the light. When the second a-si TFT T2 is driven, the first signal provided to the gate electrode of the second a-si TFT T2 through the second sensor line SL2 is the second a-si TFT. After being provided to the source electrode of T2, it is output to the drain electrode of the second a-si TFT (T2). Here, the first signal is a signal output from the reader and provided to the second sensor line SL2.

The first signal output from the drain electrode of the second a-si TFT (T2) is provided to the source electrode of the third a-si TFT (T3). Subsequently, when the third a-si TFT T3 is driven in response to the second signal provided to the gate line GL, the first signal is output to the drain electrode of the third a-si TFT T3. do. Here, the second signal is a gate driving voltage output from the driver and applied to the gate electrode of the first a-si TFT T1 through the gate line GL.

The first signal is input to the read part through the first sensor line SL1 connected to the drain electrode of the third a-si TFT T3. The subsequent operation is omitted because it has been described with reference to FIGS. 1 and 2.

According to the liquid crystal display, the light sensing unit includes a first sensor line, a second switching element, a third switching element, and a second sensor line, and the gate and source electrodes of the second switching element are connected to the second sensor line. Commonly connected.

Therefore, by keeping the number of switching elements coupled to each of the data lines constant, not only can the load on the data lines be kept the same, but also the amount of load can be reduced. As a result, crosstalk and flicker that appear on the screen of the liquid crystal display panel can be prevented, thereby improving display characteristics of the liquid crystal display panel.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (6)

A pixel portion for displaying an image, the pixel portion comprising a gate line, a data line, a first switching element connected to the gate line and the data line, and a pixel electrode connected to the first switching element; And A first sensor line receiving a first signal from a controller for controlling driving of the pixel unit, a second switching element for outputting a first signal provided through the first sensor line in response to light provided from the outside; Providing to the controller a third switching element for outputting the first signal applied from the second switching element and the first signal output from the third switching element in response to a second signal provided through a gate line. Liquid crystal display panel comprising a light sensing unit consisting of a second sensor line for. The liquid crystal display of claim 1, wherein the second switching element comprises a gate electrode branched from the first sensor line, a source electrode coupled to the gate electrode, and a drain electrode connected to the third switching element. panel. The liquid crystal display panel of claim 1, wherein the third switching element comprises a gate electrode branched from the gate line, a source electrode connected to the second switching element, and a drain electrode connected to the second sensor line. . The liquid crystal display panel of claim 1, wherein the pixel electrode comprises a transparent electrode and a reflective electrode overlapping the transparent electrode to form a transmissive portion and a reflective portion. The liquid crystal display panel according to claim 4, wherein the reflective electrode has an opening window for exposing the second switching element so that the light is provided to the second switching element. The liquid crystal display panel of claim 1, wherein the first to third switching elements are amorphous thin film transistors.