KR20080023381A - Display panel - Google Patents

Abstract

A display panel is provided to prevent image quality deterioration caused by a conventional manufacturing method by positioning the touch screen upon the lower portion of the display panel which is formed with a display substrate made of a flexible material. A display substrate(300) comprises a base substrate(100), a pixel unit(200) formed at one surface of the base substrate, and a first transparent electrode(110) formed on the other surface of the base substrate. A first polarizing unit(400) comprises a first polarizing plate(410) positioned at the upper side of the display substrate and a common electrode(420) formed at the one surface of the first polarizing plate faced to the pixel unit. A liquid crystal layer is inserted between the display substrate and the first polarizing unit. A second polarizing unit(600) comprises a second polarizing plate(610) positioned at the lower side of the display substrate, and a second transparent electrode(620) which is formed upon the one surface of the second polarizing plate faced to the first transparent electrode, and generates location information by connecting to the first transparent electrode electrically.

Description

Display panel {DISPLAY PANEL}

1 is a cross-sectional view illustrating a display panel according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view illustrating a portion of the display substrate illustrated in FIG. 1.

3 is a cross-sectional view illustrating the display substrate of FIG. 2.

4 and 5 are views illustrating a manufacturing process of the first polarizing unit illustrated in FIG. 1.

6 is a cross-sectional view of another embodiment of the first polarizing unit illustrated in FIG. 1.

7 and 8 are views illustrating a manufacturing process of the first polarizing unit illustrated in FIG. 6.

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

100: base substrate 110: first transparent electrode

200: pixel portion 300: display substrate

400: first polarizing unit 410: first polarizing plate

412: first base film 414: first lattice pattern

420: common electrode 500: liquid crystal layer

600: second polarizing unit 610: second polarizing plate

620: second transparent electrode

The present invention relates to a display panel, and more particularly, to a display panel in which a touch screen is embedded.

Recently, in order to efficiently use various display devices including a liquid crystal display device, a touch screen panel (TSP) for inputting a signal to a display surface of a display device without a remote controller or a separate input device has been applied. .

TSP has various methods such as optical, ultrasonic, capacitive, and resistive film methods, and a resistive film method for durability and portability is widely used in liquid crystal display devices requiring a small thin film type.

In the resistive type TSP, when a voltage is applied to two opposing conductive layers, when a user touches a desired point and the two conductive layers contact each other, the TSP detects a change in voltage or current generated at a contact point and converts the coordinates into coordinate values. It works as

At present, the TSP is attached to the upper portion of the liquid crystal display device, which causes the display quality of the liquid crystal display device to be degraded due to a decrease in transmittance and surface reflection. Accordingly, high-definition technology for high transmission and low reflection has been applied to the liquid crystal display device. For example, the high-definition technique may include anti-reflection (AR) treatment, anti-glare treatment, and the like.

However, the optical property improvement method as described above has a problem in that a high frequency of defects is generated due to a complicated process, and a manufacturing cost increases due to additional process costs. In addition, there is a problem that the thickness or size of the liquid crystal display including the TSP increases.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a display panel having a touch screen having an improved optical characteristic and a thin thickness.

In order to achieve the above object of the present invention, a display panel according to an embodiment includes a display substrate, a first polarizing unit, a liquid crystal layer, and a second polarizing unit. The display substrate has a base substrate, a pixel portion formed on one surface of the base substrate, and a first transparent electrode formed on the other surface of the base substrate. The first polarizing unit has a first polarizing plate disposed on the display substrate and a common electrode formed on one surface of the first polarizing plate facing the pixel portion. The liquid crystal layer is interposed between the display substrate and the first polarizing unit. The second polarizing unit is formed on one surface of the second polarizing plate disposed below the display substrate and the second polarizing plate facing the first transparent electrode, and electrically contacts the first transparent electrode to provide position information. It has a 2nd transparent electrode which generate | occur | produces.

In this case, the first polarizing plate includes a first lattice pattern formed on the first base film and the upper surface of the first base film to polarize light, and the second polarizing plate is formed of the second base film and the second base film. It is preferable to include a second grating pattern formed on the lower surface to polarize the light.

On the other hand, the base substrate is preferably made of a plastic material having flexibility.

According to the display panel, by forming a touch panel by forming a transparent electrode on one surface of the polarizing plate and the display substrate, it is possible to form an ultra-thin display panel with a built-in touch screen. In addition, as the touch screen is formed on the back of the flexible display substrate, display quality of the display panel may be improved.

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

<First Embodiment of Display Panel>

1 is a cross-sectional view illustrating a display panel according to a first exemplary embodiment of the present invention.

Referring to FIG. 1, the display panel 700 includes a display substrate 300 displaying an image, a first polarization unit 400 disposed on the display substrate 300, a display substrate 300, and a first polarization unit ( And a second polarization unit 600 disposed below the liquid crystal layer 500 and the display substrate 300 interposed therebetween.

The display substrate 300 includes a base substrate 100, a pixel portion 200 formed on one surface of the base substrate 100, and a first transparent electrode 110 formed on the other surface of the base substrate 100.

In the present invention, the base substrate 100 is made of a transparent material that can transmit light. In addition, the base substrate 100 is made of a plastic material having flexibility that is deformed by external pressure. Accordingly, the display substrate 300 is bent when the surface of the display panel 700 is pressed, so that the display panel 700 may serve as a resistive touch screen.

The pixel unit 200 is formed on one surface of the base substrate 100 and includes a thin film transistor (not shown) and a pixel electrode (not shown). Details thereof will be described later with reference to FIGS. 2 and 3.

The first transparent electrode 110 is formed on the other surface of the base substrate 100. For example, the first transparent electrode 110 may include indium tin oxide (ITO) or indium zinc oxide (IZO), which are transparent conductive materials.

The first polarizing unit 400 is disposed above the display substrate 300 and includes a first polarizing plate 410 and a common electrode 420 formed on one surface of the first polarizing plate 410.

The first polarizing plate 410 transmits light vibrating in a specific direction and absorbs or reflects light vibrating in the remaining direction. Accordingly, the first polarizer 410 polarizes the light passing through the liquid crystal layer 500. The first polarizing plate 410 is made of, for example, a poly vinyl alcohol (PVA) film or a transparent optical film.

The common electrode 420 is formed on one surface of the first polarizing plate 410 facing the pixel portion 200 of the display substrate 300. The common electrode 420 is made of, for example, an indium tin oxide (ITO) or indium zinc oxide (IZO) material, which is a transparent conductive material.

The liquid crystal layer 500 is interposed between the display substrate 300 and the first polarization unit 400. The arrangement of the liquid crystal layer 500 is changed by an electric field formed between the pixel electrode and the common electrode 420 of the pixel unit 200. As the arrangement of the liquid crystals included in the liquid crystal layer 500 is changed, the display panel 700 may change the light transmittance to display an image having a desired gray scale.

The second polarizing unit 600 is disposed under the display substrate 300 and includes a second polarizing plate 610 and a second transparent electrode 620.

The second polarizer 610 transmits light vibrating in a specific direction, and absorbs or reflects light vibrating in the remaining direction. Accordingly, the second polarizer 610 polarizes the light emitted from the backlight assembly (not shown) disposed under the display panel 700. The second polarizing plate 610 is made of, for example, a poly vinyl alcohol (PVA) film or a transparent optical film.

The second transparent electrode 620 is formed on one surface of the second polarizing plate 610 facing the first transparent electrode 110 of the display substrate 300. The second transparent electrode 620 is made of, for example, an indium tin oxide (ITO) or an indium zinc oxide (IZO) material which is a transparent conductive material.

The first transparent electrode 110 of the display substrate 300 and the second transparent electrode 620 of the second polarizing plate 610 are electrically contacted by external pressure to generate position information. The first and second transparent electrodes 110 and 620 are spaced apart from each other by an insulating adhesive member 601 formed between both ends of the first and second transparent electrodes 110 and 620.

Specifically, when the upper surface of the first polarizing plate 410 is pressed by a touch such as a pen or a finger, the first transparent electrode 110 and the second transparent electrode 620 are in contact with each other and electrically shorted. As a result, a signal having a current amount or a voltage level that varies at the contact point is generated. The touch recognition unit (not shown) connected to the display panel 700 detects the signal, converts the signal into coordinates, and operates to recognize the selected content by the touch.

The display panel 700 further includes dot spacers 602 formed between the first transparent electrode 110 and the second transparent electrode 620. The dot spacers 602 are disposed to be spaced apart from each other by the first transparent electrode 110 and the second transparent electrode 620. In one example, the dot spacers 602 are preferably formed on the second transparent electrode 620. The dot spacers 602 prevent contact between the first and second transparent electrodes 110 and 620 in the peripheral region except any contact position. Accordingly, the display panel 700 can accurately detect the position of the contact point.

As such, since the first and second transparent electrodes 110 and 620 for the touch screen function are formed on the lower side of the display substrate 300, the deterioration of image quality generated when the touch screen is formed on the front of the display panel 700 may be prevented. have.

On the other hand, since the first and second polarizers 410 and 610 are generally poor in heat resistance, it is difficult to form transparent conductive materials such as ITO on the surfaces of the first and second polarizers 410 and 610 by conventional sputtering methods. Therefore, in the present invention, a method of coating a transparent conductive material on one surface of the first and second polarizing plates 410 and 610 without degrading polarization characteristics is described. Details thereof will be described later with reference to FIGS. 4 and 6. .

2 is a plan view illustrating a portion of the display substrate illustrated in FIG. 1, and FIG. 3 is a cross-sectional view illustrating the display substrate of FIG. 2.

2 and 3, the display substrate 300 includes a base substrate 100, a pixel portion 200 formed on one surface of the base substrate 100, and a first transparent electrode formed on the other surface of the base substrate 100. 110).

The base substrate 100 is made of a transparent material through which light can be transmitted. In addition, the base substrate 100 is made of a flexible plastic material.

The pixel unit 200 includes a thin film transistor layer 220 and a pixel electrode 260.

The thin film transistor layer 220 is formed on one surface of the base substrate 100. The thin film transistor layer 220 includes gate lines GL, a gate insulating layer 210, data lines DL, a thin film transistor TFT, and a passivation layer 230.

The gate lines GL are formed on the base substrate 100 and extend in the first direction.

The gate insulating layer 210 is formed on the base substrate 100 on which the gate lines GL are formed to cover the gate lines GL. The gate insulating layer 210 may be formed of, for example, a silicon nitride layer (SiNx) or a silicon oxide layer (SiOx).

The data lines DL are formed on the gate insulating layer 210 and extend in a second direction perpendicular to the first direction so as to intersect the gate lines GL. Here, as the gate lines GL and the data lines DL are formed to cross each other, a plurality of pixels P are defined.

The thin film transistor TFT is connected to the gate line GL and the data line DL to be formed in the pixel P. The thin film transistor TFT applies an image signal applied through the data line DL to the pixel electrode 260 in response to a scan signal applied through the gate line GL.

The thin film transistor TFT includes a gate electrode 221, an active layer 222, a source electrode 223, and a drain electrode 224.

The gate electrode 221 is connected to the gate line GL and constitutes a gate terminal of the thin film transistor TFT.

The active layer 222 is formed on the gate insulating layer 210 corresponding to the gate electrode 221. The active layer 222 includes a semiconductor layer 222a and an ohmic contact layer 222b. The semiconductor layer 222a may be made of amorphous silicon (a-Si), and the ohmic contact layer 222b may be made of amorphous silicon (hereinafter, n + a-Si) doped with a high concentration of n-type impurities. .

The source electrode 223 is connected to the data line DL and is formed to extend to the upper portion of the active layer 222. The source electrode 223 constitutes a source terminal of the thin film transistor TFT.

The drain electrode 224 is formed on the active layer 222 to be spaced apart from the source electrode 223. The drain electrode 224 constitutes a drain terminal of the thin film transistor TFT. The drain electrode 224 is connected to the pixel electrode 260 through a contact hole CH formed in the passivation layer 230 and the color filter layer 240, which will be described later.

The source electrode 223 and the drain electrode 224 are disposed on the active layer 222 so as to be spaced apart from each other to form a channel of the thin film transistor TFT.

The passivation layer 230 is formed on the gate insulating layer 210 on which the data lines DL and the thin film transistor TFT are formed to cover the data lines DL and the thin film transistor TFT. The passivation layer 230 may be formed of, for example, a silicon nitride layer (SiNx) or a silicon oxide layer (SiOx).

The thin film transistor layer 220 may further include a storage line SL and a storage electrode 272. The storage line SL is formed to extend in the same direction as the gate lines GL between the gate lines GL. The storage electrode 272 is connected to the storage line SL and is formed in the pixel P. The storage line SL and the storage electrode 272 are, for example, formed of the same material on the same layer as the gate lines GL.

The storage electrode 272 faces the drain electrode 224 with the gate insulating layer 210 interposed therebetween to form a storage capacitor. The image signal applied to the pixel electrode 260 through the thin film transistor TFT is maintained for one frame by the storage capacitor.

The display substrate 300 may further include a color filter layer 240 formed on the thin film transistor layer 220. The color filter layer 240 includes a plurality of color filters 242 and a light blocking part 244.

The color filters 242 are formed to correspond to the pixels P of the thin film transistor layer 220. The color filters 242 include color filters of red (R), green (G), and blue (B), and each color filter is alternately formed to correspond to each pixel (P).

The light blocking portion 244 is formed corresponding to the pixels P. In detail, the light blocking part 244 is formed on the gate lines GL and the data lines DL, which define the pixel P of the thin film transistor layer 220. That is, the light blocking part 244 has a shape surrounding the R, G, and B color filters.

In addition, the light blocking unit 244 may be formed to correspond to the thin film transistor TFT and the storage lines SL. For example, the light blocking part 244 may be formed of a resin material having a black pigment.

The pixel electrode 260 is formed on the color filter layer 240. The pixel electrode 260 is formed independently of each pixel P. As shown in FIG. The pixel electrode 260 is connected to the drain electrode 224 of the thin film transistor TFT through the contact hole CH formed in the passivation layer 230 and the color filter layer 240.

The pixel electrode 260 is made of a transparent conductive material through which light can pass. For example, the pixel electrode 260 is made of indium zinc oxide (IZO) or indium tin oxide (ITO).

In the present invention, the base substrate 110 is made of a plastic material to serve as a touch screen. Therefore, the thin film transistor layer 220, the color filter layer 240, and the pixel electrode 260 formed on the base substrate 110 may be formed at a low temperature of 130 degrees or less.

As such, since the display substrate 300 including the thin film transistor layer 220 and the pixel electrode 260 further includes the color filter layer 240, the overall thickness of the display panel 700 may be reduced.

4 and 5 are views illustrating a manufacturing process of the first polarizing unit illustrated in FIG. 1.

4 and 5, the first polarizing unit 400 includes a first polarizing plate 410 and a common electrode 420.

In the present embodiment, the first polarizing plate 410 is made of a poly vinyl alcohol (PVA) film. Specifically, the first polarizing plate 410 is formed by stretching the PVA film and then aligning iodine molecules and dichroic dye molecules side by side in the stretching direction on the PVA film.

The common electrode 420 is formed on the surface of the first polarizer 410. In the present embodiment, the common electrode 420 is coated on one surface of the first polarizing plate 410 using a neutral beam (NB) at room temperature. Since the process of coating the common electrode 420 on the first polarizing plate 410 is performed at room temperature, the arrangement of the iodine molecules is scattered by heat, thereby preventing the polarization characteristics of the first polarizing plate 410 from being lowered. For example, the common electrode 420 is made of indium tin oxide (ITO) material.

On the other hand, this embodiment can be applied to the second polarizing unit 600. Referring to FIG. 1, the second polarizing unit 600 includes a second polarizing plate 610 and a second transparent electrode 620 formed on one surface of the second polarizing plate 610. In this case, the method of forming the second transparent electrode 620 on one surface of the second polarizing plate 610 is the same as the method of forming the common electrode 420 on one surface of the first polarizing plate 410.

Second Embodiment of Display Panel

6 is a cross-sectional view illustrating a first polarizing unit of a display panel according to a second exemplary embodiment of the present invention. 7 and 8 are views showing a manufacturing process of the first polarizing unit shown in FIG.

Except for the first polarizing unit, the display panel according to the present exemplary embodiment has the same configuration as the display panel of the first exemplary embodiment described above, and thus the detailed description thereof will be omitted, and like reference numerals refer to like elements. Let's use the name.

6, 7 and 8, the first polarizing unit 400 includes a first polarizing plate 410 and a common electrode 420. In this case, the first polarizing plate 410 includes the first base film 412 and the first grating pattern 414 formed on the top surface of the first base film 412.

The first base film 412 is made of a transparent and flexible plastic material.

The first grating pattern 414 is formed on the upper surface of the first base film 412 to polarize the light. The first grating pattern 414 has, for example, a shape in which horizontal and vertical lines intersect at regular intervals. For example, the first polarizer 410 reflects light incident in a direction parallel to the first grating pattern 414, and passes light incident in a direction perpendicular to the first grating pattern 414.

The common electrode 420 is formed on one surface of the first polarizer 410, that is, the lower surface of the first base film 412. In this embodiment, the common electrode 420 is formed by a sputtering method. Alternatively, the common electrode 420 may be formed by a coating method using the neutral beam NB described in the first embodiment. For example, the common electrode 420 is made of indium tin oxide (ITO) material.

Referring to FIGS. 7 and 8, a process of forming the common electrode 420 on one surface of the first polarizer 410 will be described.

First, the common electrode 420 is formed on one surface of the first base film 412. In this case, the common electrode 420 is formed by a sputtering method or a coating method using a neutral beam.

The metal thin film 401 is formed on the other surface of the base film 412 having the common electrode 420 formed on one surface thereof. The metal thin film 401 is made of, for example, an indium tin oxide (ITO) material.

After the transfer mold 10 having the pattern corresponding to the first lattice pattern 414 is disposed on the metal thin film 401, the transfer mold 10 is pressed onto the metal thin film 401. Thereafter, by separating the transfer mold 10 from the metal thin film 401, the first grating pattern 414 may be formed on one surface of the base film 412.

In the present exemplary embodiment, the first polarizing plate is not the PVA film but the first base film 412 having the first grating pattern 414 formed thereon. Accordingly, when the common electrode 420 is formed, a decrease in polarization characteristics of the first polarizing plate 410 due to an increase in temperature can be prevented.

On the other hand, this embodiment can be applied to the manufacturing of the second polarizing unit 600. Referring to FIG. 1, the second polarizing unit 600 includes a second polarizing plate 610 and a second transparent electrode 620 formed on the bottom surface of the second polarizing plate 610. In this case, the second polarizing plate 610 includes a second base film and a second lattice pattern formed on the bottom surface of the second base film. The second grating pattern may be formed of the same method and the same material as the first grating pattern 414 of the first polarizer 410.

When the first and second polarization units 400 and 600 are formed in the same manner as in the first and second embodiments, each of the first and second polarization units 400 and 600 has a thickness of about 0.2 mm. Accordingly, the ultra-thin display panel 700 within about 0.6 mm may be manufactured using the first and second polarizing units 400 and 600 having a thin thickness and the display substrate 300.

As described above, as the touch screen is formed using the display substrate and the polarizing plate inside the display panel, a display panel having a thin thickness can be manufactured.

In addition, when the display substrate is made of a flexible material, the entire display panel is easily bent. Accordingly, since the touch screen is disposed below the display panel, it is possible to prevent the deterioration of image quality that occurs when the touch screen is formed on the front of the display panel.

On the other hand, according to the lower arrangement of the touch screen, a separate process for improving the optical characteristics in the display panel is unnecessary, thereby reducing the occurrence of defective rate and manufacturing cost.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (10)

A display substrate having a base substrate, a pixel portion formed on one surface of the base substrate, and a first transparent electrode formed on the other surface of the base substrate; A first polarizing unit having a first polarizing plate disposed on the display substrate and a common electrode formed on one surface of the first polarizing plate facing the pixel portion; A liquid crystal layer interposed between the display substrate and the first polarizing unit; And A second polarizing plate disposed under the display substrate and a second transparent electrode formed on one surface of the second polarizing plate facing the first transparent electrode and electrically contacting the first transparent electrode to generate position information; A display panel comprising a second polarizing unit having a. According to claim 1, wherein the first polarizing plate comprises a first grating pattern formed on the upper surface of the first base film and the first base film to polarize the light, The second polarizing plate includes a second base film and a second grating pattern formed on a lower surface of the second base film to polarize light. The display panel of claim 2, wherein the first and second grid patterns are formed by a printing process. The display panel of claim 2, wherein the common electrode is formed on a lower surface of the first base film, and the second transparent electrode is formed on an upper surface of the second base film. The display panel of claim 1, wherein the common electrode and the first and second transparent electrodes are made of indium tin oxide or indium zinc oxide. The display panel of claim 1, wherein the common electrode and the second transparent electrode are formed at room temperature using a neutral beam. The display panel of claim 1, wherein the base substrate is made of a flexible plastic material. The method of claim 1, wherein the pixel unit A thin film transistor formed on the base substrate; And And a pixel electrode electrically connected to the thin film transistor. The display panel of claim 8, wherein the display substrate further comprises a color filter formed at a position corresponding to the pixel electrode. The display panel of claim 9, wherein the display substrate further comprises a light shielding unit that blocks light.

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