KR20090052240A - Liquid crystal display device having touch screen and method for fabricating the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a touch screen, the configuration of which includes a thin film transistor on a first transparent substrate, a lower array substrate on which a pixel electrode electrically connected to the thin film transistor is formed, and a second transparent substrate. A liquid crystal display panel comprising an upper array substrate on which a black matrix and a color filter layer are formed, and a liquid crystal layer formed between the substrates; A touch screen comprising a transparent conductive film formed on a rear surface of a second transparent substrate constituting the liquid crystal display panel, a position sensing sensor film and a transparent conductive film stacked on the transparent conductive film; And a backlight assembly formed under the liquid crystal display panel and providing light to the liquid crystal display panel.

Touch screen, position sensor film, transparent conductive film, transparent conductive film

Description

Liquid crystal display device with touch screen and manufacturing method thereof {LIQUID CRYSTAL DISPLAY DEVICE HAVING TOUCH SCREEN AND METHOD FOR FABRICATING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having a touch screen capable of increasing transmittance and slimming a panel thickness, and a manufacturing method thereof.

The touch screen is a state-of-the-art input device that replaces a keyboard and a mouse, and is a device in which a user touches a monitor using a hand or a touch pen to perform a desired task by mounting the touch screen on a monitor.

Such a touch screen is an ideal device capable of performing intuitive tasks under a GUI (Graphic User Interface) environment (Windows operating system).

Accordingly, touch screens can be widely used in computer board training, simulation applications, office automation applications, educational applications, and game applications.

Such a touch screen generates a photo current according to light reflected by an object to be touched, for example, a finger or a touch pen, charges the generated charge, and outputs a voltage according to the charged charge. Detect the position of the object.

In general, since the touch screen is configured in the form of a thin film, the touch screen is mounted on the liquid crystal display panel and used.

A conventional liquid crystal display device having a touch screen will be described with reference to FIGS. 1 and 2 as follows.

1 is a schematic configuration diagram of a liquid crystal display device having a touch screen adhered according to the prior art.

2 is a schematic exploded view of a liquid crystal display before the touch screen according to the related art is bonded.

According to the prior art, a liquid crystal display device having a touch screen may include: a liquid crystal display panel 10; A lower polarizing plate 15 and an upper polarizing plate 17 formed on the lower and upper surfaces of the liquid crystal display panel 10, respectively; And a touch screen 20 in the form of a thin film adhered to the upper polarizing plate 17.

 Here, the liquid crystal display panel 10, as shown in Figure 2, made of a transparent material, the lower array substrate 11 is formed with a switching element; An upper array substrate 13 on which images of various colors are implemented; It is composed of a liquid crystal layer (not shown) formed between these substrates and whose arrangement direction is controlled by an electric field.

In addition, the touch screen 20 in the form of a thin film, as shown in Figure 2, a transparent ITO substrate (Indium Tin Oxide substrate) (21); A position sensor film 23 attached to the ITO substrate 21 and recognizing X and Y position coordinates of an object in contact with the liquid crystal display panel; It consists of an ITO film 25 adhered to the position sensor film (23).

A method of manufacturing a liquid crystal display device having a touch screen according to the related art having the above configuration will now be described with reference to FIG. 2.

 Although not shown in the drawing, first, a TFT forming process as a switching element is performed on the lower array substrate (see 11 in FIG. 2), and an alignment layer (not shown) is connected to a pixel electrode (not shown) electrically connected to the TFT (not shown). (Not shown).

Next, although not shown in the drawing, a black matrix (not shown) defining an image display area on the upper array substrate (see 13 in FIG. 2), a color filter layer (not shown) and a common electrode (not shown) for implementing a plurality of colors are provided. The process of forming an illustration film and an orientation film (not shown) is performed.

Subsequently, as shown in FIG. 2, a seal pattern (not shown) defining a pixel display area of the lower array substrate 11 or the upper array substrate 13 is formed. After forming a liquid crystal layer (not shown) in the lower array substrate 11 and the upper array substrate 13 are bonded.

Next, the lower polarizing plate 15 and the upper polarizing plate 17 are formed on the outer surfaces of the bonded lower array substrate and the upper array substrate, respectively, to complete the manufacturing process of the liquid crystal display panel.

Subsequently, as shown in FIG. 2, the process of adhering the touch screen 20 to the upper surface of the upper polarizing plate 17 is performed to complete the manufacturing process of the liquid crystal display device having the touch screen.

In this case, the touch screen 20 is an ITO substrate 21 bonded to the upper surface of the liquid crystal display panel 10 and a position sensor bonded to the ITO substrate 21 and recognizing X and Y position coordinates of an object. The film 23 and the ITO film 25 are comprised.

As described above, according to the LCD and the manufacturing method having a touch screen according to the prior art has the following problems.

According to a liquid crystal display device having a touch screen and a manufacturing method thereof according to the prior art, the transmittance is reduced by the ITO substrate because the touch screen is adhered onto a separate ITO substrate before mounting on the liquid crystal display panel.

In addition, according to the liquid crystal display device having a touch screen and a manufacturing method thereof according to the prior art, the color reproduction of the color filter itself may be lowered because the ITO substrate is on the liquid crystal display panel.

In addition, according to the prior art liquid crystal display device having a touch screen and a manufacturing method thereof, the touch screen is composed of a separate ITO substrate, a position sensor film and an ITO film, the liquid crystal display of the liquid crystal display panel and the touch screen The overall thickness and weight of the device is increased.

Furthermore, according to the liquid crystal display device having a touch screen according to the prior art and a method for manufacturing the same, a liquid crystal display panel and a touch screen are separately manufactured, and the liquid crystal display panel and the touch screen thus manufactured are bonded to each other to form a liquid crystal display device. This increases the cost of parts.

Accordingly, the present invention has been made to solve the above problems according to the prior art, an object of the present invention is to reduce the thickness of the liquid crystal display device while increasing the transmittance and improve the color reproduction rate of the liquid crystal display having a touch screen In providing a device.

According to an aspect of the present invention, a liquid crystal display device having a touch screen includes: a lower array substrate on which a thin film transistor and a pixel electrode electrically connected to the thin film transistor are formed on a first transparent substrate, and a second transparent substrate; A liquid crystal display panel comprising an upper array substrate having a black matrix and a color filter layer formed thereon, and a liquid crystal layer formed between the substrates; A touch screen comprising a transparent conductive film formed on a rear surface of a second transparent substrate constituting the liquid crystal display panel, a position sensing sensor film and a transparent conductive film stacked on the transparent conductive film; And a backlight assembly formed under the liquid crystal display panel and providing light to the liquid crystal display panel.

According to an aspect of the present invention, there is provided a liquid crystal display device having a touch screen, the method including: forming a thin film transistor and a pixel electrode electrically connected to the thin film transistor on a first transparent substrate; Forming a black matrix and a color filter layer on the second transparent substrate; Forming a transparent conductive film on a rear surface of the second transparent substrate; Forming a liquid crystal layer between the first transparent substrate and the second transparent substrate; And sequentially forming a position sensor film and a transparent conductive film on the transparent conductive film.

According to the liquid crystal display device and a manufacturing method having a touch screen according to the present invention has the following advantages.

According to the liquid crystal display device having a touch screen according to the present invention and a method of manufacturing the same, a color filter substrate is used instead of a separate transparent substrate without being adhered to a separate transparent substrate before the touch screen is mounted on the liquid crystal display panel. (I.e., the upper array substrate), the transmissivity is improved by eliminating the need for a separate transparent substrate.

In addition, according to the liquid crystal display device having a touch screen and a method of manufacturing the same according to the present invention, it is possible to reduce the color reproduction of the color filter itself, which may be caused by a separate ITO substrate on the upper portion of the liquid crystal display panel. Can be.

In addition, according to the liquid crystal display device having a touch screen and a method of manufacturing the same according to the present invention, since the touch screen is formed on a color filter substrate (ie, an upper array substrate) instead of a separate ITO substrate, Compared to the liquid crystal display panel and the touch screen combined, the overall thickness of the liquid crystal display device becomes thinner and the weight becomes smaller.

Therefore, according to the liquid crystal display device having a touch screen and a method of manufacturing the same according to the present invention, since the touch screen is not formed separately and formed on the color filter substrate of the liquid crystal display panel, a separate transparent substrate is not required, thereby reducing the cost of components. Savings.

Hereinafter, a liquid crystal display device having a touch screen according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic configuration diagram of a liquid crystal display device having a touch screen according to the present invention.

4 is a schematic exploded view of a liquid crystal display device having a touch screen according to the present invention.

According to an exemplary embodiment of the present invention, a liquid crystal display device having a touch screen includes: a liquid crystal display panel 100; A touch screen 160 adhered to an upper surface of the liquid crystal display panel 100; A lower polarizing plate 171 and an upper polarizing plate 173 formed on a lower surface of the liquid crystal display panel 100 and an upper surface of the touch screen 160, respectively; And a backlight assembly (not shown) provided under the liquid crystal display panel 100 to send light to the liquid crystal display panel.

 As illustrated in FIG. 4, the liquid crystal display panel 100 includes a switching element (not shown) and a pixel electrode (not shown) electrically connected to the lower substrate (not shown) made of a transparent material. A lower array substrate (110) formed thereon; An upper array substrate 130 on which a black matrix (not shown) that blocks light and a color filter layer (not shown) of various colors are formed in a pixel region defined by the black matrix (not shown); It is composed of a liquid crystal layer (not shown) formed between these substrates and whose arrangement direction is controlled by an electric field. In addition, the pixel electrode (not shown) and the common electrode (not shown) generating an electric field are formed on the upper array substrate 130 or the lower array substrate 110. In this case, the common electrode (not shown) is formed on the upper array substrate 130 in the TN mode, and is formed on the lower array substrate 110 in the IPS mode.

In addition, the thin film type touch screen 160, as shown in Figure 4, is formed on the upper surface of the upper array substrate 130, a transparent conductive film made of a transparent material such as indium tin oxide (ITO) 141; A position sensor film 161 which is attached to a surface of the transparent conductive film 141 and recognizes a position of an object contacting the liquid crystal display panel, that is, X and Y position coordinates; The ITO film 163 adhered to the position sensor film 161.

A method of manufacturing a liquid crystal display device having a touch screen according to the present invention having the above configuration will be described below with reference to FIGS. 5A to 5F.

5A through 5F are cross-sectional views illustrating a method of manufacturing a liquid crystal display device having a touch screen according to the present invention.

Herein, a method of manufacturing a liquid crystal display device in TN (Twist nemetic) mode will be described. However, the present invention is not limited to this TN mode, but can also be applied to IPS (In-Plane Switching) mode, VA (Vertical Alignment) mode, or other modes. Do.

As shown in FIG. 5A, a metal material is deposited on the lower substrate 111 made of transparent glass by a sputtering method, and then selectively patterned by a mask process to form a gate line (not shown) and the gate line ( A gate electrode 113 is formed to extend from the drawing.

In this case, the metal material for forming the gate line may be selected from Al-based metals such as Al and Al alloys, Ag-based metals such as Ag and Ag alloys, and Mo-based metals such as Mo and Mo alloys, Cr, Ti, and Ta. do.

In addition, they may include two membranes of different material properties, that is, the lower layer and the upper layer thereon. Here, the upper layer is made of a low resistivity metal, for example, an Al-based metal or an Ag-based metal so as to reduce signal delay or voltage drop of the gate line.

On the other hand, the lower layer may be made of other materials, particularly materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) or indium zinc oxide (IZO), such as Ti, Ta, Cr, and Mo-based metals. Or an example of the combination of the lower layer and the upper layer is a Cr / Al-Nd alloy.

Next, a gate insulating film 115 made of an inorganic insulating material such as silicon nitride (SiNx) is formed on the lower substrate 111 including the gate line (not shown) and the gate electrode 113.

Subsequently, a semiconductor layer (not shown) made of a hydrogenated amorphous silicon layer or the like is formed on the gate insulating film 115.

Next, an ohmic contact layer (not shown) made of a material such as n + hydrogenated amorphous silicon in which silicide or n-type impurities are heavily doped is formed on the semiconductor layer (not shown).

Subsequently, the ohmic contact layer and the semiconductor layer are selectively patterned by a mask process using a photolithography process technology to form an active pattern 117 and an ohmic contact pattern 118.

Thereafter, a metal material for forming a data line is deposited on the lower substrate 111 including the active pattern 117 and the ohmic contact pattern 118 by a sputtering method, and then selectively by a mask process using a photolithography process technology. Patterning is performed to form a data line (not shown), a source electrode 119 protruding from the data line (not shown), and a drain electrode 121 spaced apart from the source electrode 119 by a predetermined distance, respectively.

Although not shown, the data line (not shown) is formed to cross the gate line (not shown), and the source electrode 119 and the drain electrode 121 are formed under the gate electrode (not shown). Together with 113, a thin film transistor (not shown) which is a switching element is configured.

In addition, a channel of the thin film transistor (not shown) is formed in the active pattern 117 between the source electrode 119 and the drain electrode 121.

As the metal material for forming the data line (not shown), an Al-based metal, an Ag-based metal, a Mo-based metal, Cr, Ti, Ta, or the like may be used, and may be formed in multiple layers.

Next, an organic material having excellent planarization characteristics and a photosensitive property, an insulating material having a low dielectric constant, or an inorganic material on the entire surface of the lower substrate 111 including the data line (not shown) and the source / drain electrodes 119 and 121. A protective film 123 made of silicon nitride, which is a material, is formed.

Subsequently, the passivation layer 123 is selectively patterned by a mask process using a photolithography process technology to form a contact hole (not shown) exposing a portion of the drain electrode 121 in the passivation layer 123.

Next, as shown in FIG. 5B, a metal material layer (not shown) made of a transparent conductive material such as indium tin oxide (ITO) or indium zic oxide (IZO) on the passivation layer 123 including the contact hole (not shown). C) is deposited by a sputtering method and then selectively removed by a mask process using a photolithography process technology to form the pixel electrode 125.

In this case, when the data voltage is applied to the pixel electrode 113, the common electrode of the upper array substrate (not shown; see 130 of FIG. 5C) to which a common voltage is applied (not shown; see 137 of FIG. 5C). By generating an electric field, the liquid crystal molecules of the liquid crystal layer (not shown; see 150 of FIG. 5E) between the pixel electrode 125 and the common electrode 127 are arranged.

 Although not shown in the figure, a process of forming an alignment layer (not shown) for arranging liquid crystal molecules in a predetermined direction on the passivation layer 123 including the pixel electrode 125 is performed.

Meanwhile, as illustrated in FIG. 5C, a black matrix 133 is formed on the upper substrate 131 to define a plurality of unit cell regions with an opaque metal material such as Cr.

At this time, the black matrix 133 prevents the decrease in contrast by absorbing light incident from adjacent cells.

Next, a color filter layer 135 of red (R), green (G), and blue (B) is formed on the upper substrate 131 surface between the black matrices 133.

In this case, the color filter layer 135 includes a color filter of red (R), green (G), and blue (B) to allow color display by transmitting light of a specific wavelength band.

Subsequently, a common electrode 137 made of a transparent conductive material is formed on the upper substrate 131 including the color filter layer 135 and the black matrix 133. Here, although the case in which the common electrode 137 is formed on the upper substrate 131 has been described, the common electrode 137 may be formed on the lower substrate 111 according to the driving mode of the liquid crystal display panel. That is, when the driving mode of the liquid crystal display panel is the IPS mode (In-Plane Switching mode), the common electrode 137 is formed on the lower substrate 111.

Although not shown, a process of forming an alignment layer (not shown) on the common electrode 137 to arrange liquid crystal molecules in a predetermined direction is performed.

Next, as illustrated in FIG. 5D, a conductive material made of a transparent material is deposited on the rear surface of the upper substrate 131 by sputtering to form a transparent conductive film 141. In this case, the material for forming the transparent conductive film 141 may be any of indium tin oxide (ITO), indium zic oxide (IZO), or a transparent conductive material.

Subsequently, a seal pattern (not shown) defining each pixel region is formed around each pixel region on the upper surface of the lower array substrate 110 which has been subjected to the array forming process.

Next, the liquid crystal is dropped into the pixel region in the seal pattern to form the liquid crystal layer 150.

Subsequently, the upper array substrate 130 is bonded to the lower array substrate 110 on which the liquid crystal layer 15 is formed to be spaced apart by a predetermined distance to form the liquid crystal display panel 100. In this case, a spacer (not shown) is formed between the lower array substrate 110 and the upper array substrate 130 to maintain a uniform gap therebetween.

Next, the position of an object contacting the liquid crystal display panel 100 on the transparent conductive film 141 formed on the rear surface of the upper array substrate 130 constituting the liquid crystal display panel 100 where the bonding process is performed, that is, the X and Y coordinates. After adhering the position sensing sensor film 161 to recognize the ITO film 163 on the position sensor film 161 again. In this case, the ITO film 163 may be used as long as IZO or transparent conductive material other than ITO.

Subsequently, the lower polarizing plate 171 and the upper polarizing plate 173 are formed on the lower surface of the lower array substrate 110 and the upper surface of the ITO film 163, respectively.

Next, a backlight assembly (not shown) for transmitting light to the liquid crystal display panel 100 is mounted below the lower polarizing plate 171 of the lower array substrate 110.

In this manner, after performing the array process of the lower array substrate 110 and the upper array substrate 130 and forming the liquid crystal layer 150 between the lower array substrate 110 and the upper array substrate 130; In addition, the process of forming the touch screen 160 directly on the rear surface of the upper array substrate 130 is completed to complete the manufacturing process of the liquid crystal display device having the touch screen 160 embedded therein.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

Accordingly, the scope of the present invention is not limited thereto, but various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims are also within the scope of the present invention.

1 is a schematic configuration diagram of a liquid crystal display device having a touch screen adhered according to the prior art.

2 is a schematic exploded view of a liquid crystal display before the touch screen according to the related art is bonded.

3 is a schematic configuration diagram of a liquid crystal display device having a touch screen according to the present invention.

4 is a schematic exploded view of a liquid crystal display device having a touch screen according to the present invention.

5A through 5F are cross-sectional views illustrating a method of manufacturing a liquid crystal display device having a touch screen according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100: liquid crystal display panel 110: lower array substrate

111: lower substrate 113: gate electrode

115: gate insulating film 117: active pattern

118: ohmic contact pattern 119: source electrode

121: drain electrode 123: protective film

125 pixel electrode 130 upper array substrate

131; Upper Board 133: Black Matrix

135 color filter layer 137 common electrode

141: transparent conductive film 161; Position sensor film

163: transparent conductive film 171: lower polarizing plate

173: upper polarizing plate

Claims (13)

A lower array substrate having a thin film transistor and a pixel electrode electrically connected to the thin film transistor on a first transparent substrate, an upper array substrate having a black matrix and a color filter layer formed on a second transparent substrate, and a liquid crystal formed between these substrates A liquid crystal display panel composed of layers; A touch screen comprising a transparent conductive film formed on a rear surface of a second transparent substrate constituting the liquid crystal display panel, a position sensing sensor film and a transparent conductive film stacked on the transparent conductive film; And And a backlight assembly formed under the liquid crystal display panel, the backlight assembly providing light to the liquid crystal display panel. The liquid crystal display of claim 1, further comprising a first polarizing plate and a second polarizing plate formed on the lower array substrate surface and the upper surface of the touch screen, respectively. The liquid crystal display device of claim 1, wherein the transparent conductive film is formed of ITO, IZO, or a metallic material of a transparent material. The liquid crystal display device of claim 1, wherein the transparent conductive film is formed of a metal material of ITO, IZO, or transparent material. The liquid crystal display of claim 1, further comprising a common electrode formed on the lower array substrate or the upper array substrate. Forming a thin film transistor and a pixel electrode electrically connected to the thin film transistor on the first transparent substrate; Forming a black matrix and a color filter layer on a second transparent substrate bonded to the first transparent substrate; Forming a transparent conductive film on the back surface of the second transparent substrate; Forming a liquid crystal layer between the first transparent substrate and the second transparent substrate; And sequentially forming the position sensor film and the transparent conductive film on the transparent conductive film. The method of claim 6, further comprising forming a lower polarizer and an upper polarizer on the lower array substrate and the upper surface of the transparent conductive film, respectively. The method of claim 6, wherein the transparent conductive film is formed of ITO, IZO, or a metallic material of a transparent material. The method of claim 6, wherein the transparent conductive film is formed of ITO, IZO, or a metallic material of a transparent material. The method of claim 6, further comprising forming a lower polarizer and an upper polarizer on the lower array substrate and the upper surface of the transparent conductive film, respectively. 11. The method of claim 10, further comprising forming a backlight assembly for providing light to the lower array substrate and the upper array substrate under the lower polarizing plate. The method of claim 6, further comprising: forming a first alignment layer on the first transparent substrate after forming the pixel electrode, and forming a second alignment layer on a second transparent substrate after forming the common electrode. Method of manufacturing a liquid crystal display device having a touch screen, characterized in that it further comprises. The method of claim 6, further comprising forming a common electrode on the first transparent substrate or the second transparent substrate.

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