JPH09274195A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high-grade display images free from unequal display, to enhance workability and to reduce a cost by embedding a part or the whole of transparent electrodes on at least one substrate of substrates into the thickness direction of the substrates. SOLUTION: This liquid crystal display device is constituted by digging grooves 13 of the line width equal to the line width of the transparent electrodes 3 in the positions to be provided with the transparent electrodes 3 as wiring electrodes on the glass substrate 1 and embedding the transparent electrodes 3 into these grooves 13. The grooves 13 are otherwise so formed that the transparent electrodes 3 are only partly embedded into the positions corresponding to the transparent electrodes 3 disposed as the wiring electrodes on the glass substrate 1. The thin-film materials used for the transparent electrodes 3 are generally transparent ITO having high electric conductivity. A method for forming the thin film by a sputtering method or EB and pattering the film by photolithography is possible as the method for forming the transparent electrodes 3 in the position of the grooves 13. On the other hand, a screen printing method is possible as well. In such a case, the device is suitable for a liquid crystal module for products, such as monitors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for displaying an image on a liquid crystal panel having a liquid crystal sandwiched between glass substrates.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device is inferior in screen size and the number of pixels to a cathode ray tube (hereinafter, referred to as CRT), but on the other hand, it is excellent in weight and volume, and thus is portable. I was able to be positioned in a product field that I emphasized. At present, as liquid crystal display devices used in notebook type personal computers and word processors, there are prepared 10 to 12 inch size pixels with 640 x 480 dots or 600 x 800 dots, and the number of CRT pixels. However, the display performance is sufficiently excellent as a display.

However, in the simple matrix type liquid crystal display device, a phenomenon called crosstalk occurs depending on the design of the liquid crystal panel and the drive circuit, and the degree of crosstalk varies depending on the type of pattern to be displayed. This crosstalk is a state in which shadows are confirmed in the horizontal and vertical directions of the projected image (shadowing).
When a voltage is applied so as to turn on a certain pixel by a line-sequential method as a driving method of the liquid crystal panel, a slight voltage is applied to the pixel other than the turned-on pixel, which causes a display different from the normal display. Further, distortion of the signal waveform is generated even in the case of an alternating signal, and crosstalk is also generated by application of the voltage. Furthermore, the generation is greatly influenced by the capacitance component of the liquid crystal panel generated by the liquid crystal material, the cell gap, and the like and the wiring resistance value of the transparent electrode.

FIG. 1 is a sectional view showing the structure of a color STN liquid crystal display element in the conventional simple matrix type liquid crystal display device as described above. In FIG. 1, a substrate K1 including a glass substrate 1 and a transparent electrode 3 formed thereon is provided on one side, and an alignment film 4 made of polyimide or the like is further formed on the substrate K1. ing. On the opposite side, a glass substrate 2, a color filter layer 6 formed thereon, a top coat layer 7 made of an organic substance formed thereon for obtaining smoothness, and a transparent film formed thereon. A substrate K2 including an electrode 8 is provided, and an alignment film 9 made of polyimide or the like is formed on the substrate K2 similarly to the alignment film 4. The substrate K1 and the substrate K2 configured as described above are adhered to each other with the seal resin 11 printed on the periphery of at least one of the substrates via the spacer 10 so as to keep their gaps constant. Color STN with liquid crystal 12 sealed in the gap
It constitutes a liquid crystal display element.

Next, the substrates K1 and K2 will be described. 8A and 8B are cross-sectional views of the substrate K1 and the substrate K2, respectively, in which the transparent electrodes 3 and 8, the color filter layer 6 and the top coat layer 7 are formed as shown in the figure. There is. As a film forming method of the transparent electrodes 3 and 8 here, the sputtering film forming technique using an In—Sn oxide (ITO) target is most often adopted at present. There are various methods for actually forming the ITO film, and the ITO film can be formed by the conventional method, that is, the printing method, and a certain result has been achieved. However, it is difficult to form a thin film, only a thick film can be formed, and a thin line pattern cannot be formed. Further, the firing temperature is 400 to 600 ° C., and there is a restriction from the glass substrate.

On the other hand, in the method of forming the ITO film by the sputtering method or the EB (electron beam) method, the baking temperature is as low as 200 to 400 ° C. and the glass substrates 1 and 2 are not damaged. The electric resistance value is about 2,000 Å, which is about 10 ohm / □, and the film quality is closely packed, so that the electric conductivity can be secured even if the crystal grains themselves are small. Further, in order to form a film having uniform electric characteristics on a large-area glass substrate, it depends on a device and a target, but is excellent in mass productivity. If a photolithography is used to form the wiring pattern of the transparent electrode, it is possible to achieve a punching width of 20 μm to several μm, and the narrower the punching width, the higher the fineness and the panel transmittance can be increased.

A sheet resistance of 7 to 10 ohms / □ is required to make a product that satisfies users with a 10-inch color STN (640 × 480 dots) using such a transparent electrode. . If the area resistance value is larger than that, crosstalk increases in the liquid crystal panel, and the threshold voltage value in the liquid crystal panel causes a difference between the left and right regions, which causes a phenomenon called luminance inclination. This crosstalk is a shadow of a vertical line or a horizontal line due to a display pattern such as gradation or a character pattern.

FIG. 9 shows a crosstalk 20 when a quadrangle 19 is displayed on a liquid crystal module 18 in a liquid crystal display device.
It shows the appearance of. In the future, in the color STN liquid crystal display element, screen sizes of 12 type to 17 type are considered, and SVGA to XGA, SXG as display capacities.
A monitor compatible with A or the like is receiving attention as a CRT alternative monitor.

Against such a tendency, there is a concern that display unevenness may occur due to an increase in crosstalk and a luminance gradient. Therefore, a drive circuit that takes into consideration a voltage application waveform to be corrected according to a display pattern is adopted, It is required to reduce C (capacitance component) and R (resistance component) of the liquid crystal panel by reducing the sheet resistance value of the transparent electrode.

In addition, with respect to the narrowing of the gap of the liquid crystal panel in order to increase the display response speed, the capacitance component of the liquid crystal panel increases, so that crosstalk and display unevenness due to an increase in the luminance gradient similarly occur. For example, since the response speed of the panel is proportional to the square of the gap, the gap of the liquid crystal panel tends to be narrowed in order to bring it closer to the CRT. In recent years, 4 to 5 μm, which is aimed at moving images by the STN of APT drive, is used. The gap is required, and the display unevenness becomes a problem at this time as well.

[0011]

However, in the conventional liquid crystal display device as described above, the area of the liquid crystal panel is increased,
The trend toward higher resolution and higher speed is also in STN and TFT, and in particular, while these markets are expected to expand in the future,
In STN, if an attempt is made to increase the display area in order to increase the area, the wiring of the transparent electrode becomes long, which increases the wiring resistance value, so that the R component of the liquid crystal panel becomes nonuniform and increases, and crosstalk and There is a problem in that the phenomenon of luminance inclination appears and display unevenness occurs. Also, when the pixel density is increased for higher resolution, it is necessary to reduce the line width of the wiring electrode. There has been a problem that the wiring resistance value becomes large, the crosstalk and the brightness gradient are also increased, and display unevenness tends to occur. Such display unevenness and uniformity problems also occur in TFTs.

Further, if the gap of the liquid crystal panel is reduced in order to increase the display response speed, the capacitance component of the liquid crystal panel increases, which also causes the problem of uneven display.

The present invention solves the above-mentioned problems, and displays an image or S in a large screen size monitor device.
In moving image display in a TN type liquid crystal display device, it is possible to obtain a high-quality display image without display unevenness, simplify the manufacturing work of a product that obtains these characteristics, and improve its workability, and reduce the cost. Provided is a liquid crystal display device that can realize the following.

[0014]

In order to solve the above-mentioned problems, a liquid crystal display device according to claim 1 of the present invention is a liquid crystal display device in which liquid crystal is sandwiched between at least a pair of substrates. A part or all of the transparent electrode on at least one of the substrates is embedded in the thickness direction of the substrate.

A liquid crystal display device according to a second aspect is a liquid crystal display device in which a liquid crystal is sandwiched between at least a pair of substrates, and a groove is formed in a part of a portion of the substrate where a transparent electrode is formed. Is formed, a metal layer is embedded in the groove, and a transparent electrode is formed thereon so as to be electrically connected to the metal layer.

A liquid crystal display device according to a fifth aspect is a liquid crystal display device in which a liquid crystal is sandwiched between at least a pair of substrates, and sandblasting is performed on a part of a portion of the at least one substrate where a transparent electrode is formed. A groove is formed by, a metal layer is embedded in the groove, and a transparent electrode electrically connected to the metal layer is formed thereon.

A liquid crystal display device according to a sixth aspect is a liquid crystal display device in which a liquid crystal is sandwiched between at least a pair of substrates, and a part of a portion of at least one of the substrates where a transparent electrode is formed is etched. A groove is formed by, a metal layer is embedded in the groove, and a transparent electrode electrically connected to the metal layer is formed thereon.

A liquid crystal display device according to a seventh aspect is a liquid crystal display device in which a liquid crystal is sandwiched between at least a pair of substrates, and at least one of the substrates is diced at a part of a portion where a transparent electrode is formed. A groove is formed by sawing, a metal layer is embedded in the groove, and a transparent electrode electrically connected to the metal layer is formed thereon.

The liquid crystal display device according to claim 8 is a liquid crystal display device in which liquid crystal is sandwiched between at least a pair of substrates, and a metal is formed at a portion of a portion of at least one of the substrates where a transparent electrode is formed. A wire is embedded, and a transparent electrode electrically connected to the metal wire is formed on the wire.

A liquid crystal display device according to a ninth aspect is a liquid crystal display device in which a liquid crystal is sandwiched between at least a pair of substrates, and at least a part of a portion of the substrate where a transparent electrode is formed is a metal. A layer is formed, an insulating layer having a thickness corresponding to that of the metal layer is provided at other locations, and a transparent electrode electrically connected to the metal layer is formed thereon.

According to the above arrangement, the wiring resistance value in the liquid crystal element is reduced to suppress crosstalk and luminance inclination,
In addition to preventing display unevenness due to these, it is possible to easily realize a large display size, a fine display screen, and a high display response speed.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A liquid crystal display device showing an embodiment of the present invention will be described below with reference to the drawings.

As the liquid crystal display device of the present embodiment, as in the conventional example shown in FIG. 1, a simple matrix type liquid crystal display device will be taken as an example, and the color STN liquid crystal display element will be described. In this explanation, it is assumed that the basic configuration of the entire apparatus is the same as that of the conventional example shown in FIG.

Therefore, the basic structure of the liquid crystal display device of this embodiment will be described below with reference to FIG. In FIG. 1, a substrate K1 including a glass substrate 1 and a transparent electrode 3 formed thereon is provided on one side, and an alignment film 4 made of polyimide or the like is further formed on the substrate K1. ing. On the opposite side, a glass substrate 2, a color filter layer 6 formed thereon, and a top coat layer 7 made of an organic substance formed thereon to obtain smoothness,
Substrate K2 composed of transparent electrode 8 formed thereon
Is provided, and an alignment film 9 made of polyimide or the like is formed on the substrate K2 similarly to the alignment film 4. The substrate K1 and the substrate K2 configured as described above are the spacer 1
A sealing resin 11 printed on the periphery of at least one of the substrates so as to maintain a constant gap therebetween, and a liquid crystal 12 is sealed in the gap to form a color STN liquid crystal display element. are doing.

As described above, the structure of the liquid crystal display device of this embodiment is basically the same as the conventional one, but the structure of the substrate K1 itself is different from the conventional one.
Therefore, here, only the substrate K1 will be described in detail.

The substrate K1 in the liquid crystal display device showing the first embodiment will be described. 2 and 3 are cross-sectional views of the substrate K1 in the present embodiment. In FIG. 2, a groove 13 having a line width equivalent to that of the transparent electrode 3 is dug at a position where the transparent electrode 3 is provided as a wiring electrode on the glass substrate 1.
The transparent electrode 3 is embedded in the groove 13. On the other hand, in the case of FIG. 3, the groove 13 has several tens to several tens of holes so that only a part of the transparent electrode 3 is embedded at a position corresponding to the transparent electrode 3 provided as a wiring electrode on the glass substrate 1. μ
It is formed with a width of about m.

2 and 3, the thin film material used for the transparent electrode 3 is transparent and highly conductive ITO.
Is common. As a method of forming the transparent electrode 3 at the position of the groove 13, a sputtering method or an EB is used as in the conventional method.
It is possible to use a method of forming a thin film with and patterning by photolithography. On the other hand, a screen printing method is also possible. This screen printing method has very good workability in consideration of patterning properties when the pitch is large, and although it has a problem of transmittance, it increases the light amount of the backlight. Suitable for LCD modules for products such as monitors, which can be used for a while.

The substrate K1 in the liquid crystal display device showing the second embodiment will be described. FIG. 4 is a sectional view of the substrate K1 in the present embodiment. In FIG. 4, reference numeral 13 denotes a groove formed on the glass substrate 1, and further, the groove 1
A metal layer 14 is buried in the layer 3. Then, the transparent electrode 3 is patterned at a position corresponding to the groove 13 on the glass substrate 1.

As described above, since the substrate K1 constitutes a liquid crystal display element in the liquid crystal display device, the groove 13 on the glass substrate 1 is formed in the electrode wiring depending on the display capacity and screen size of the liquid crystal display element. The combined groove pitch and groove width are required. For example, a 10-inch VGA (640 x 48
With 0 dots, the groove pitch of the grooves 13 is required to be about 0.1 mm, and the groove width is required to be about several μm to 30 μm. Further, depending on the screen size and the display capacity (the number of dots) to be commercialized in the future, it is necessary to have a narrower groove pitch or groove width.

Therefore, sand blasting, etching, and dicing saw can be considered as the method for forming the groove 13. First, the sand blasting method will be described below.

FIG. 5 is a flow chart showing the manufacturing process of the glass substrate 1 by the sandblast method. First, FIG.
As shown in FIG. 5B, a resist 15 is applied on the glass substrate 1 shown in FIG.
A resist pattern P of (c) is formed. Glass substrate 1
In the portion 1a of the resist pattern P which is not covered with the resist 15 portion, the groove 13 shown in FIG. 5D is formed by excavating the hard sand fine particles under a certain condition. Then, if the resist pattern P on the glass substrate 1 is removed, the glass substrate 1 in which the groove 13 was formed as shown in FIG.5 (e) is obtained.

When a fine resist pattern P is required, a film made of glass paste often used in plasma displays is attached to the glass substrate 1 and then a resist 15 is applied to form the resist pattern P. There is a way to do it. Thereafter, a manufacturing process similar to that shown by FIG. 5 can be performed. Since a photomask is used in this method, a fine pattern can be stably formed in a large area.

Next, an etching method will be described as a method of forming the groove 13. As an etching mask used in this etching method, there is an inorganic film, a photosensitive resist, or a chromium film having HF resistance which is patterned by photolithography in advance.

These mask patterns are designed according to the desired pitch and width of the grooves 13. Then, the glass substrate 1 is etched using an HF-based etchant. At this time, if the adhesiveness between the resist and the glass substrate 1 is not sufficient, a pinhole defect may occur, or the surface of the glass substrate 1 may be melted extremely thin to deteriorate the resolution.

Another method of forming the groove 13 using a dicing saw will be described. In the method using the dicing saw, the glass substrate 1 is dug by a mechanical method, and the groove width is determined by the cutting edge of the dicing saw. Further, in order to obtain an accurate groove pitch, a precision pulse motor or the like that can configure an accurate mechanism is used.

However, in the case of a color filter substrate or a film substrate, it is difficult to dig a groove by dicing saw or sandblast, and the etching method is most suitable for these substrates.

Next, a method of forming the metal layer 14 will be described. As shown in FIG. 3, when only a part of the wiring electrode such as the transparent electrode 3 is embedded in the groove 13, that part may have a light-shielding property, and the part embedded in the groove 13 of the wiring electrode Can be composed of the metal layer 14 shown in FIG. This metal layer 14 is formed by using a metal by sputtering or E
After forming a thin film with B or the like, patterning is performed by photolithography to form in the groove 13. Besides forming the thin film by the sputtering method or EB as described above, the thin film can be formed by electroless plating. After the thin film is formed in this way, the thin film is patterned by photolithography to form a metal layer. 14 may be formed. When the metal layer 14 is formed of a thin film by electroless plating as described above, the metal layer 14 having a thickness of several μm can be formed. As a method of forming the metal layer 14, a printing method may be considered in addition to the above.

The transparent electrode 3 is provided on the metal layer 14 formed by each of the above methods, and electrical conduction is established between the metal layer 14 and the transparent electrode 3. At this time, if the metal layer 14 is thicker than the depth of the groove 13, the metal layer 14 must be planarized so that conduction can be obtained through the polishing process.

The substrate K1 in the liquid crystal display device showing the third embodiment will be described. FIG. 6 is a cross-sectional view of the substrate K1 according to the present embodiment, and the metal layer 14 shown in FIG.
Instead of, the metal wire 16 is embedded in the glass substrate 1. In this substrate K1, as shown in FIG. 6, the metal wire 16 is provided so as to be located at a part of the wiring electrode such as the transparent electrode 3. As the material of the metal wire 16, Ti, Cr, Au or the like is suitable.

A method of forming the substrate K1 having the above structure will be described below. First, a groove having a wire diameter and a corresponding width of the metal wire 16 is dug in the glass substrate 1 by the method using sandblasting, etching, and dicing saw as described above, and the metal wire 16 is embedded in this groove. As a fixing method after embedding the metal wire 16, mechanical pressure is applied to the metal wire 16 to embed it, or a glass paste, an acrylic transparent adhesive resin, or the like in the gap between the metal wire 16 and the groove. Is filled and cured to fix the metal wire 16. The metal wire 16 is formed so that one arc thereof is located on the surface of the glass substrate 1 as shown in FIG. 6 so as to be electrically connected to the transparent electrode 3 serving as a wiring electrode thereon. .

Although it is possible to embed the metal wire 16 when manufacturing the glass substrate 1, it is difficult to produce the metal wire 16 because it is in-line in the conventional glass substrate manufacturing method such as corban and fusion. is there.

The substrate K1 in the liquid crystal display device showing the fourth embodiment will be described. FIG. 7 is a cross-sectional view of the substrate K1 in the present embodiment, which is formed by forming the metal layer 14 and the smoothing layer 17 on the glass substrate 1 and then forming the transparent electrode 3 which is a wiring electrode.

A method of forming the substrate K1 having the above structure will be described below. First, the metal layer 14 is formed on the glass substrate 1. As a forming method, there is a method of patterning by a screen printing method, or a method of forming a thin film by sputtering or EB or a film by electroless plating and then patterning by photolithography. Further, the formation position of the metal layer 14 is a position corresponding to a part of the formation position of the wiring electrode such as the transparent electrode 3, and the width of the metal layer 14 is several μm.
m to several tens of μm is suitable. In this case, the metal layer 14 on the glass substrate 1 is in a protruding state, and the smoothing layer 17 is provided so as to fill the thickness of the metal layer 14. As the material of the smooth layer 17, a thermosetting or ultraviolet curing acrylic resin is used. When this resin is applied by spin coating or roll coating, the resin on the surface of the metal layer 14 is subjected to a polishing step after coating. May be scraped off or patterned by photolithography.

As another coating method, there is a method of burying the resin for the smooth layer 17 in a portion other than the metal layer 14 by screen printing, and if the surface property is not good after this coating, it is desirable to pass through a polishing step. . After the above steps, the transparent electrode 3 is further provided so as to be electrically connected to the metal layer 14.
To form

Although the case where the glass substrate 1 is used as the substrate has been described here, the same can be applied to the case where a color filter or a film is used. With each of the above configurations, the wiring resistance value in the liquid crystal element is reduced to suppress crosstalk and luminance inclination, and display unevenness due to these is prevented, and the display size is increased and the display screen is highly refined. Higher response speed can be easily realized.

Therefore, in the image display on the monitor device having a large screen size and the moving image display on the STN type liquid crystal display device, it is possible to obtain a high-quality display image without display unevenness and to obtain a product having these characteristics. The manufacturing work can be simplified, the workability can be improved, and the cost can be reduced.

In the description of each of the above-described embodiments, a liquid crystal display device having only one set of liquid crystal elements in which liquid crystal is sandwiched between a pair of substrates K1 and K2 will be described as an example. However, also in a liquid crystal display device including a plurality of sets of this liquid crystal element, the same effect can be obtained by configuring each liquid crystal element with the same configuration as in each of the above embodiments.

[0048]

As described above, according to the present invention, the wiring resistance value in the liquid crystal element is reduced to suppress the crosstalk and the luminance gradient, and display unevenness due to these is prevented, and the display size is increased and It is possible to easily realize a finer display screen and a higher display response speed.

Therefore, in the image display on the monitor device having a large screen size and the moving image display on the STN type liquid crystal display device, it is possible to obtain a high-quality display image without display unevenness and to obtain a product having these characteristics. The manufacturing work can be simplified, the workability can be improved, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a general color STN liquid crystal display device.

FIG. 2 is a sectional view showing a configuration of a substrate K1 according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing another configuration of the substrate K1 in the same embodiment.

FIG. 4 is a sectional view showing a configuration of a substrate K1 according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing a manufacturing process of the substrate K1 in the same embodiment.

FIG. 6 is a sectional view showing the structure of a substrate K1 according to a third embodiment of the present invention.

FIG. 7 is a sectional view showing the structure of a substrate K1 according to a fourth embodiment of the present invention.

FIG. 8: Substrates K1 and K2 in a conventional liquid crystal display device
Sectional view showing the structure of

FIG. 9 is an explanatory diagram of crosstalk of the liquid crystal module in the conventional example.

[Explanation of symbols]

 3 Transparent Electrode 13 Groove 14 Metal Layer 15 Resist 16 Metal Wire 17 Smooth Layer

Claims (11)

[Claims] 1. A liquid crystal display device comprising a liquid crystal sandwiched between at least a pair of substrates, wherein a part or all of transparent electrodes on at least one of the substrates is embedded in a thickness direction of the substrate. Liquid crystal display device. 2. A liquid crystal display device comprising a liquid crystal sandwiched between at least a pair of substrates, wherein a groove is formed at a portion of at least one substrate where a transparent electrode is formed, and the metal layer is formed in the groove. And a transparent electrode is formed thereon so as to be electrically connected to the metal layer. 3. The liquid crystal display device according to claim 2, wherein the metal layer embedded in the groove is formed by electroless plating. 4. The liquid crystal display device according to claim 2, wherein the metal layer embedded in the groove is formed by a printing method. 5. A liquid crystal display device comprising a liquid crystal sandwiched between at least a pair of substrates, wherein a groove is formed by sandblasting in a part of a portion of at least one of the substrates where a transparent electrode is formed, and the groove is formed in the groove. A liquid crystal display device, wherein a metal layer is embedded, and a transparent electrode electrically connected to the metal layer is formed on the metal layer. 6. A liquid crystal display device comprising a liquid crystal sandwiched between at least a pair of substrates, wherein a groove is formed by etching at a portion of a portion of at least one of the substrates where a transparent electrode is formed, and the groove is formed in the groove. A liquid crystal display device, wherein a metal layer is embedded, and a transparent electrode electrically connected to the metal layer is formed on the metal layer. 7. A liquid crystal display device comprising liquid crystal sandwiched between at least a pair of substrates, wherein a groove is formed by dicing saw at a part of a portion of at least one substrate where a transparent electrode is formed, and the groove is formed. A liquid crystal display device, wherein a metal layer is embedded in the transparent layer, and a transparent electrode electrically connected to the metal layer is formed thereon. 8. A liquid crystal display device comprising a liquid crystal sandwiched between at least a pair of substrates, wherein a metal wire is embedded in a portion of a portion of at least one of the substrates where a transparent electrode is formed, and the metal wire is formed thereon. A liquid crystal display device, characterized in that a transparent electrode is formed which is electrically connected to a wire. 9. A liquid crystal display device comprising a liquid crystal sandwiched between at least a pair of substrates, wherein a metal layer is formed on a part of a portion of at least one of the substrates where a transparent electrode is formed, and other than that. A liquid crystal display device, wherein an insulating layer having a thickness corresponding to that of the metal layer is provided at a position, and a transparent electrode electrically connected to the metal layer is formed thereon. 10. The liquid crystal display device according to claim 9, wherein the metal layer is formed by an electroless plating method. 11. The liquid crystal display device according to claim 9, wherein the metal layer is formed by a printing method.