KR20070050617A - Liquid crystal display device - Google Patents

Abstract

The present invention is to provide a liquid crystal display device suitable for reducing the weight and thickness, the production cost by configuring a carbon nano tube (CNT) layer as an electron emission source, the liquid crystal display for achieving the above object The apparatus includes a flat panel backlight unit having a carbon nanotube layer and used as a lower substrate; An upper substrate bonded to the flat panel backlight unit and having a predetermined space; And a liquid crystal layer filled between the upper substrate and the flat panel backlight unit.

Carbon nano tube, liquid crystal panel

Description

Liquid Crystal Display Device

1 is a cross-sectional view of a structure of a liquid crystal display device having a backlight unit according to the related art.

2 is a cross-sectional view of a structure of a liquid crystal display device having a backlight unit according to another conventional technology.

3 is a cross-sectional view of a structure of a liquid crystal display according to a first embodiment of the present invention.

4 is a cross-sectional view of a structure of a liquid crystal display according to a second exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100, 200: flat backlight unit 101, 201: first substrate

102, 202: first coating layer 103, 203: carbon nanotube layer

104, 204: second substrate 105, 205: fluorescent layer

106,206: spacer 107,207: electrode layer

110, 210: upper substrate 111, 211: black matrix layer

112, 212: color filter layers 113, 213: common electrode

130: liquid crystal layer 131, 231: first polarizing plate

132, 232: gate electrode 133, 233: gate insulating film

134,234 Active layer 134a, 234a Ohmic contact layer

135,235 data lines 135a, 235a source electrodes

135b and 235b drain electrodes 136 and 236 pixel electrodes

137,237: second polarizer 220: lower substrate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device suitable for reducing weight and thickness by reducing carbon nanotubes (CNTs) as electron emission sources, and reducing production costs.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices.However, due to the weight and size of the CRT itself, We couldn't respond actively to demands.

Therefore, in the trend of miniaturization and light weight of various electronic products, CRT has a certain limit in weight and size.

It is expected that the CRT will be replaced by a liquid crystal display (LCD) using an electro-optical effect, a plasma display device (PDP) using a gas discharge, and an EL display device using an electroluminescent effect ( ELD (Electro Luminescence Display) and the like, among them, researches on liquid crystal display devices are actively conducted.

In order to replace the CRT, liquid crystal display devices having advantages such as small size, light weight, and low power consumption have been actively developed. Recently, the liquid crystal display device has been developed enough to perform a role as a flat panel display device. As it is used for a monitor of a desktop computer and a large information display device, the demand for a liquid crystal display device is continuously increasing.

Since most of the liquid crystal display devices are light-receiving devices that display images by controlling the amount of light coming from the outside, a separate light source, that is, a back light unit, for irradiating light to the liquid crystal panel is necessary.

In general, a backlight unit used as a light source of the liquid crystal display device is a method of disposing a cylindrical light emitting lamp, and is divided into an edge method and a direct method.

First, as shown in FIG. 1, a liquid crystal display device having an edge type backlight unit according to the related art includes a liquid crystal panel 10 including upper and lower substrates 1 and 11 filled with liquid crystal therebetween. It is composed of a backlight unit 20 configured in an edge manner at the bottom.

In this case, the edge type backlight unit is provided with a lamp unit on the side of the light guide plate 21 for guiding the light, and the lamp unit is inserted into both ends of the lamp 22 and the lamp 22 that emit light, thereby providing a lamp. A lamp housing having a protecting lamp holder (not shown) and a lamp reflecting plate surrounding an outer circumferential surface of the lamp 22 and having one side fitted to a side of the light guide plate 21 to reflect light emitted from the lamp toward the light guide plate 21. 23) and light scattering means 24 composed of a plurality of diffusion sheets and diffusion plates between the light guide plate 21 and the liquid crystal panel 10 to enhance the light scattering effect. All.

The edge method in which the lamp unit is installed on the side of the light guide plate 21 is mainly applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer.

In the liquid crystal panel 10, a gate line (not shown) having a gate electrode 12 is arranged on one side of the lower substrate 11 in one direction, and the data intersects the gate line vertically to define each pixel area. Lines 15 are arranged, and a plurality of pixel electrodes 16 are formed in a matrix form in each pixel region defined by crossing the gate lines and data lines 15.

In the region where the gate line and the data line 15 cross each other, a plurality of thin film transistors (TFTs) which are switched by signals of the gate lines to transfer the signals of the data lines 15 to the pixel electrodes 16 are formed. It is.

'2' is a black matrix layer, '3' is a color filter layer, '4' is a common electrode, '5' is a first polarizing plate '6' is a second polarizing plate, '13' is a gate insulating film, and '14' '14' is an active layer, '14a' is an ohmic contact layer, '15a' is a source electrode, and '15b' is a drain electrode.

On the other hand, the liquid crystal display device having a direct backlight method according to another conventional technique, as shown in Figure 2, the liquid crystal panel 30 is composed of a liquid crystal panel 30, a lower substrate filled with a liquid crystal between the lower portion, The backlight unit 40 is configured in a direct manner.

At this time, the backlight unit of the direct type is mainly developed as the screen size begins to be enlarged to 20 inches or more, and includes a plurality of light emitting lamps 42 arranged in a row on the cover bottom 41 and a liquid crystal panel ( It consists of a light scattering means 43 composed of a plurality of diffusion sheets and diffusion plates on the light emitting lamp 42 to direct light directly to the front of the 30.

The light emitting lamp 42 may be configured as a cold cathode fluorescent lamp (CCFL) or an external electrode light emitting lamp.

The configuration of the liquid crystal panel 30 is the same as the prior art shown in FIG.

As described above, the liquid crystal display device having the conventional backlight unit has the following problems.

Since light emitted from the light emitting lamp is incident to the light scattering means through the light guide plate or the air, and light diffused or condensed from the light scattering means is incident on the liquid crystal panel, there is a problem that the thickness and weight by the light scattering means are increased. There is a limit in reducing the production cost because it must be provided with a diffusion sheet and a diffusion plate to configure.

The present invention has been made to solve the above problems, an object of the present invention is to configure a carbon nano tube (CNT) layer as an electron emission source to reduce the weight and thickness, liquid crystal suitable for reducing the production cost It is to provide a display device.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a flat panel backlight unit having a carbon nanotube layer and used as a lower substrate; An upper substrate bonded to the flat panel backlight unit and having a predetermined space; And a liquid crystal layer filled between the upper substrate and the flat panel backlight unit.

First and second polarizing plates are provided on the upper portion of the flat panel backlight unit and the outer upper portion of the upper substrate, respectively.

A gate line arranged in one direction having a gate electrode on the first polarizing plate above the planar backlight unit, a data line arranged to perpendicularly intersect the gate line to define each pixel region, and a matrix in each pixel region And a plurality of thin film transistors formed in a plurality of pixel electrodes formed in a shape and in an area where the gate line and the data line cross each other.

According to another exemplary embodiment of the present invention, a liquid crystal display device includes: a liquid crystal panel including upper and lower substrates filled with liquid crystals; And a flat panel backlight unit having a carbon nanotube layer attached to a rear surface of the liquid crystal panel.

A first polarizing plate is provided between the flat panel backlight unit and the lower substrate of the liquid crystal panel, and a second polarizing plate is provided at an outer upper portion of the upper substrate.

The flat panel backlight unit includes a first conductive layer composed of a screen printing method on a first substrate, a carbon nano tube (CNT) layer formed on the first conductive layer, and the first substrate. And a plurality of spacers for maintaining a gap between the second substrate, the fluorescent layer formed on the inner surface of the second substrate, and the first and second substrates.

The carbon nanotube layer of the first substrate is characterized in that it further comprises an electrode layer provided with a plurality of holes to expose the carbon nanotube layer.

Edges of edges of the first and second substrates are closed by a sealing material, and the inside thereof is in a vacuum state.

Gate lines arranged in one direction including gate electrodes on the lower substrate of the liquid crystal panel, data lines arranged to vertically cross the gate lines to define each pixel area, and a plurality of matrixes formed in each pixel area; Pixel electrodes and a plurality of thin film transistors configured to intersect the gate line and the data line.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

First embodiment

A liquid crystal display device according to a first embodiment of the present invention will be described.

3 is a cross-sectional view of a structure of a liquid crystal display device according to a first embodiment of the present invention.

In the liquid crystal display according to the first exemplary embodiment of the present invention, as shown in FIG. 3, the flat panel backlight unit 100 and the upper substrate 110 are bonded to the flat panel backlight unit 100 in a predetermined space. ) And a liquid crystal layer 130 filled between the upper substrate 110 and the flat panel backlight unit 100.

First and second polarizing plates 131 and 137 are provided at an upper portion of the flat panel backlight unit 100 and an outer upper portion of the upper substrate 110, respectively.

As in the above configuration, the flat panel backlight unit 100 functions not only as a light source but also as a lower substrate on which a TFT array is formed.

The flat panel backlight unit 100 includes a first conductive layer 102 formed by a screen printing method on a first substrate 101 and a carbon nano tube formed on the first conductive layer 102. Gap between the CNT) layer 103, the second substrate 104, the fluorescent layer 105 formed on the inner surface of the second substrate 104, and the first and second substrates 101 and 104. And spacers 106 to make it.

In this case, an electrode layer 107 having a plurality of holes may be further provided on the carbon nanotube layer 103 of the first substrate 101, and the spacers 106 may be provided with an electrode layer. 107 is formed on top.

Edges of edges of the first and second substrates 101 and 104 are blocked by a seal material, and the inside thereof is in a vacuum state of about 10 ⁻⁶ torr.

The flat panel backlight unit 100 configured as described above is driven by applying a high voltage to the fluorescent layer 105 and grounding the electrode layer 107 and the carbon nanotube layer 103. Electrons are generated in the carbon nanotube layer 103 by the potential difference generated in the electrode layer 107, and the generated electrons strike the fluorescent layer 105 to generate visible light, and the generated visible light is generated on the second substrate 104. It is emitted upward through).

A first polarizing plate 131 is formed on the flat panel backlight unit 100 as described above, and a TFT array having a TN structure or an IPS structure is arranged on the first polarizing plate 131. A general array structure arranged as follows will be described as an example.

First, a gate line (not shown) having a gate electrode 132 is arranged in one direction on the first polarizing plate 131, and the data line 135 is vertically intersected with the gate line to define each pixel area. A plurality of pixel electrodes 136 are formed in a matrix form in each pixel region defined by crossing each of the gate lines and the data lines 135.

In the region where the gate line and the data line 135 intersect, a plurality of thin film transistors (TFTs) which are switched by a signal of the gate line to transfer the signal of the data line 135 to the pixel electrodes 136 are formed. It is.

Referring to a configuration of an example of a thin film transistor TFT formed at a portion where the gate line and the data line 135 intersect, a gate line having a gate electrode 132 on the first polarizing plate 131 (not shown) ) Is arranged in one direction, a gate insulating film 133 is formed on the planar backlight unit 100 including the gate electrode 132, and is disposed on the gate insulating film 133 on the gate electrode 132. An island-shaped active layer 134 is formed, and a source electrode 135a is formed to protrude from the data line 135 and overlap an upper portion of one side of the gate electrode 132. The drain electrode 135b is formed to be spaced apart by a predetermined interval and overlap the upper portion of the gate electrode 132.

In this case, the active layer 134 is made of amorphous silicon, and an ohmic contact layer 134a made of n + amorphous silicon is further formed on the active layer 134 except for the channel region.

In the above description, the pixel electrode 136 is directly connected to the drain electrode 135b. For example, the pixel electrode 136 may be formed to be connected to each other through the contact hole on the passivation layer having the contact hole.

In addition, the upper substrate (color filter substrate) 110 has a black matrix layer 111 for blocking light in portions other than the pixel region, and R, G, and B color filter layers 112 for expressing color colors. A common electrode (Vcom) 113 made of a transparent conductive material for realizing an image is formed.

In addition, the upper substrate 110 and the lower plate-shaped backlight unit 100 formed as described above have a predetermined space by a spacer (not shown) for maintaining a cell gap, and a sealant (not shown). ) Is attached. And liquid crystal is formed in the space inside a seal material.

Although the liquid crystal display having the above configuration is not shown in the drawing, after the flat panel backlight unit 100 is manufactured, the first polarizing plate 131 is attached to the upper portion thereof, and the first polarizing plate 131 is attached thereto. After the TFT process is performed on the planar backlight unit 100 and the color filter process is performed on the upper substrate 110, the cell process and the module process are performed.

Second embodiment

The configuration of the backlight unit according to the second embodiment of the present invention will be described.

4 is a cross-sectional view of a structure of a liquid crystal display according to a second exemplary embodiment of the present invention.

In the liquid crystal display according to the second exemplary embodiment of the present invention, as shown in FIG. 4, the flat panel backlight unit 200 and the flat panel backlight unit 200 are attached to each other with a predetermined space. And a liquid crystal panel 300 having upper and lower substrates 210 and 220 filled with liquid crystal therebetween.

That is, the flat panel backlight unit 200 is attached to the rear surface of the liquid crystal panel 300 as a sealing material.

In this case, the first polarizing plate 231 is provided between the flat panel backlight unit 200 and the lower substrate 220 of the liquid crystal panel 300, and the second polarizing plate 232 is disposed on the outer upper portion of the upper substrate 210. It is provided.

The flat panel backlight unit 200 includes a first conductive layer 202 formed by a screen printing method on a first substrate 201 and a carbon nano tube formed on the first conductive layer 202. Maintain a gap between the CNT) layer 203, the second substrate 204, the fluorescent layer 205 formed on the inner surface of the second substrate 204, and the first and second substrates 201, 204. And spacers 206 for the purpose.

In this case, an electrode layer 207 having a plurality of holes may be further provided on the carbon nanotube layer 203 of the first substrate 201 so that the spacer 206 may be provided. Are formed on the electrode layer 207.

Edges of edges of the first and second substrates 201 and 204 of the flat panel backlight unit 200 are blocked with a seal material, and the inside thereof is in a vacuum state of about 10 ⁻⁶ torr.

The flat panel backlight unit 200 configured as described above is driven by applying a high voltage to the fluorescent layer 205 and grounding the electrode layer 207 and the carbon nanotube layer 203. Electrons are generated in the carbon nanotube layer 203 due to the potential difference generated in the electrode layer 207, the electrons hit the fluorescent layer 205 to generate visible light, and the generated visible light is generated in the second substrate 204. It exits through the top.

A TFT array having a TN structure or an IPS structure is arranged in the liquid crystal panel 300 attached to the flat backlight unit 200. Hereinafter, a general array structure having a TN structure will be described as an example.

First, a gate line (not shown) having a gate electrode 232 is arranged on a lower substrate 220 of the liquid crystal panel 300 in one direction, and the data is perpendicular to the gate line so as to define each pixel area. Lines 235 are arranged, and a plurality of pixel electrodes 236 are formed in a matrix form in each pixel region defined by crossing the gate lines and the data lines 235.

In the region where the gate line and the data line 235 cross each other, a plurality of thin film transistors TFTs are switched by signals of the gate lines to transfer the signals of the data lines 235 to the pixel electrodes 236. It is.

Referring to the configuration of the thin film transistor TFT formed at the portion where the gate line and the data line 235 intersect, a gate line having a gate electrode 232 on the lower substrate 220 (not shown) The gate insulating film 233 is formed on the planar backlight unit 200 including the gate electrode 232, which is arranged in one direction, and the island is formed on the gate insulating film 233 on the gate electrode 232. An active layer 234 having a shape is formed, and a source electrode 235a is formed so as to protrude from the data line 235 and overlap the upper portion of one side of the gate electrode 232. The drain electrode 235b is formed to be spaced apart from each other and overlap the upper portion of the gate electrode 232.

In this case, the active layer 234 is made of amorphous silicon, and an ohmic contact layer 234a made of n + amorphous silicon is further formed on the active layer 234 except for the channel region.

In the above description, the pixel electrode 236 is directly connected to the drain electrode 235b. For example, the pixel electrode 236 may be formed to be connected to each other through the contact hole on the passivation layer having the contact hole without being directly connected.

In addition, the upper substrate (color filter substrate) 210 has a black matrix layer 211 for blocking light in portions other than the pixel region, and R, G, and B color filter layers 212 for expressing color colors. A common electrode (Vcom) 213 made of a transparent conductive material for realizing an image is formed.

In addition, the upper substrate 210 and the lower plate-shaped backlight unit 200 formed as described above have a predetermined space by a spacer (not shown) for maintaining a cell gap, and a sealant (not shown). ) Is attached. And liquid crystal is formed in the space inside a seal material.

Although the liquid crystal display having the above configuration is not shown in the drawing, the liquid crystal panel 300 is fabricated after the flat panel backlight unit 200 and the first and second polarizing plates 231 and 232 are manufactured. The flat plate type backlight unit 200 is attached to the first polarizing plate 231 on the rear surface.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be defined by the claims.

The liquid crystal display according to the present invention as described above has the following effects.

First, since the liquid crystal display device is constructed by using a flat panel backlight unit having carbon nanotubes (CNT) directly as a lower substrate, a light scattering means composed of a separate light diffusing film is not required. Can reduce production costs.

Second, by directly attaching a flat panel backlight unit having carbon nanotubes (CNT) directly to the liquid crystal panel, no light scattering means consisting of a separate light diffusing film is required, which reduces weight and thickness and reduces production costs. Can be saved.

Claims (9)

A flat panel backlight unit having a carbon nanotube layer and used as a lower substrate; An upper substrate bonded to the flat panel backlight unit and having a predetermined space; And a liquid crystal layer filled between the upper substrate and the flat panel backlight unit. The method of claim 1, And a first polarizing plate and a second polarizing plate, respectively, on the upper portion of the flat panel backlight unit and the outer upper portion of the upper substrate. The method of claim 2, A gate line arranged in one direction having a gate electrode on the first polarizing plate on the flat backlight unit; A data line arranged to vertically intersect the gate line to define each pixel region; A plurality of pixel electrodes formed in a matrix in each pixel region; And a plurality of thin film transistors configured in an area where the gate line and the data line cross each other. A liquid crystal panel composed of upper and lower substrates filled with liquid crystal therebetween; And a flat panel backlight unit having a carbon nanotube layer attached to a rear surface of the liquid crystal panel. The method of claim 4, wherein A first polarizing plate is provided between the flat panel backlight unit and the lower substrate of the liquid crystal panel, and a second polarizing plate is provided on the outer upper portion of the upper substrate. The method according to claim 1 or 4, The flat panel backlight unit includes a first conductive layer composed of a screen printing method on a first substrate; A carbon nano tube (CNT) layer formed on the first conductive layer, A second substrate opposed to the first substrate, A fluorescent layer formed on the inner surface of the second substrate, And a plurality of spacers for maintaining a gap between the first and second substrates. The method of claim 6, And an electrode layer having a plurality of holes to expose the carbon nanotube layer on the carbon nanotube layer of the first substrate. The method of claim 6, Edges of edges of the first and second substrates are sealed with a sealing material, and the inside thereof is in a vacuum state. The method of claim 5, A gate line arranged in one direction including a gate electrode on the lower substrate of the liquid crystal panel; A data line arranged to vertically intersect the gate line to define each pixel region; A plurality of pixel electrodes formed in a matrix in each pixel region; And a plurality of thin film transistors configured in an area where the gate line and the data line cross each other.

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