JP2002055358A - Liquid crystal display device and method of manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device at a low cost without damaging an antireflection function imparted to the display surface of a polarizing plate. SOLUTION: The liquid crystal display device is provided with a liquid crystal display panel 11 having a liquid crystal layer provided between a facing glass substrate 2 provided on the display surface side and a TFT glass substrate 1 opposed thereto and a transparent conductive film 7 for shielding radiation noise, formed on the display surface of the facing glass substrate 2 and having >=40 nm and <=160 nm film thickness.

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 having a function of blocking unnecessary radiation noise and a method of manufacturing the same.

[0002]

2. Description of the Related Art A liquid crystal display panel generally includes, as basic components, electrodes formed on two glass substrates facing each other and a liquid crystal material sandwiched between the two glass substrates. In this liquid crystal display panel, a voltage corresponding to the display content is applied to each pixel electrode, whereby the liquid crystal is turned on / off, or displays an intermediate state. At this time, the voltage is changed on the counter electrode side in accordance with the driving method.

For example, a TFT liquid crystal display panel is driven by a voltage that is inverted every line and every field, but is driven by a driving voltage of a TFT-side substrate provided with TFT elements, that is, connected to the TFT-side substrate. For the purpose of lowering the power supply voltage of the driver IC, the counter electrode is also AC driven at a voltage close to the threshold voltage of the liquid crystal.

[0004] By the voltage change of the counter electrode as described above,
Conventionally, in a liquid crystal display device, unnecessary radiation noise occurs,
It affects peripheral devices. In particular, in recent years, car navigation systems and in-vehicle displays using liquid crystal display devices have become widespread, and in vehicles equipped with these, if the distance between the car antenna and the liquid crystal display device cannot be sufficiently ensured, the above-mentioned radiated noise causes For example, reception of AM radio broadcasts is greatly hindered.

As described above, when the antenna position cannot be sufficiently moved away from the liquid crystal display device due to restrictions in the design of the car, the following measures are taken. (1) A transparent conductive film is provided on the display surface side polarizing plate of the liquid crystal display device, that is, on the display surface (front surface) of the front polarizing plate. (2) A transparent conductive thin film is provided on the display surface of the front polarizing plate of the liquid crystal display device. Such a configuration is disclosed in, for example, Japanese Patent Laid-Open No. 5-150.
No. 214. The configuration is as shown in FIG.

The liquid crystal display device shown in FIG. 6 includes a liquid crystal display panel 51, a liquid crystal module 52 including a backlight (not shown), a driving circuit (not shown), and the like. The liquid crystal module 52 includes a front polarizing plate 52a on a display surface,
A back polarizing plate 52b is provided on the back surface. Further, on the front side (display surface side) of the liquid crystal module 52, a transparent conductive film (transparent conductive film) 54 for blocking the radiation noise for absorbing the radiation noise is provided. A ground terminal 55 connected to the ground is connected to the transparent electrode 54. As a result, the radiation noise signal is absorbed by the transparent electrode 54 and flows to the ground via the ground terminal 55.

[0007]

However, the above-described conventional configuration has the following problems. That is, the front polarizing plate 52a of the liquid crystal display panel is usually subjected to an antireflection treatment using a multilayer film in order to reduce the reflectance of the display surface and enhance the display function. Therefore, in the above-described conventional configuration, when the anti-reflection treatment is performed on the front polarizing plate 52a, the transparent conductive film (transparent conductive film) 54 for shielding radiation noise provided on the front polarizing plate 52a. , The antireflection function of the front polarizing plate 52a is impaired.

Further, when a transparent conductive film (transparent conductive film) 54 for shielding radiation noise is provided on the front polarizing plate 52a, the transparent conductive film (transparent conductive film) for shielding radiation noise such as the grounding terminal 55 is provided. Since a structure for electrically connecting the (film) 54 to an external ground terminal or the like is required separately, there is a problem that the manufacturing cost is increased.

Therefore, the present invention provides a liquid crystal display device having a low-cost structure without impairing the antireflection function due to the antireflection treatment performed on the display surface of the polarizing plate, and its manufacture. It is intended to provide a method.

[0010]

A liquid crystal display device according to the present invention comprises a liquid crystal display panel having a liquid crystal layer provided between a front substrate provided on a display surface side and a rear substrate opposed thereto. A transparent conductive film for blocking radiation noise, which is formed on the display surface of the front substrate and has a thickness of 40 nm or more and 160 nm or less, is provided.

According to the above structure, the transparent conductive film for shielding radiation noise is formed not on the surface of the display-side polarizing plate (front polarizing plate) but on the display surface of the front substrate. When the anti-reflection treatment is performed on the surface polarizer, the anti-reflection function of the front polarizer is not impaired by the radiation noise blocking transparent conductive film.

Further, since the transparent conductive thin film is formed directly on the display surface (front surface) of the front substrate, the transparent conductive thin film can have a high protection function against unnecessary radiation noise from the liquid crystal display panel.

Further, since the radiation noise blocking transparent conductive film is set to have a film thickness of 40 nm or more, the radiation noise blocking transparent conductive film formed on the front substrate during manufacture of the liquid crystal display device is made of another material. Damage due to friction when it comes into contact with the device, further peeling, excessive damage due to scratching, the ability to absorb unnecessary radiation noise is significantly reduced, or etching during the manufacturing process of the liquid crystal display device It is possible to prevent a situation such as peeling due to processing.
Further, when the film thickness is less than 40 nm, the contamination on the film forming surface of the transparent conductive film for shielding radiation noise is emphasized by light interference and the display quality deteriorates. However, since the film thickness is 40 nm or more, Such a situation can also be prevented.

Further, since the radiation noise blocking transparent conductive film is set to have a thickness of 160 nm or less, the light transmittance at the time of display can be maintained in a good range, and the radiation noise blocking transparent conductive film can be used. A situation in which the display function of the liquid crystal display device is reduced can be prevented.

Further, the transparent conductive film for shielding radiation noise is formed on the display surface (front surface) of the front substrate, and has a configuration included in the liquid crystal display panel. Therefore, in order to connect the radiation noise blocking transparent conductive film to the ground potential, a conductive casing or the like originally provided in the liquid crystal display device can be used,
No additional grounding member is required. Thereby, cost increase can be suppressed.

In the above liquid crystal display device, the radiation noise blocking transparent conductive film may have a sheet resistance of 300 Ω / cm ² or less.

According to the above configuration, since the transparent conductive film for shielding radiation noise has a sheet resistance of 300 Ω / cm ² or less, it can have a good blocking function for unnecessary radiation noise.

In the liquid crystal display device described above, the radiation noise blocking transparent conductive film may have a sheet resistance of 60 Ω / cm ² or less.

According to the above configuration, the radiation noise shielding transparent is provided.
The bright conductive film has a sheet resistance of 60Ω / cm. ^TwoSince
Furthermore, AM band noise can be better blocked.
You.

The above liquid crystal display device may have a configuration in which a polarizing plate is provided on the front surface of the transparent conductive film for blocking radiation noise.

According to the above configuration, in the configuration in which the polarizing plate is provided on the display surface side of the front substrate of the liquid crystal display panel, the transparent conductive film for shielding radiation noise is not formed on the surface of the polarizing plate. In other words, the anti-reflection treatment may be performed only on the front surface as in the related art. Therefore, there is no need to change the manufacturing method of the polarizing plate, and it is possible to suppress a decrease in productivity and an increase in cost of the polarizing plate, that is, the liquid crystal display device.

In the above liquid crystal display device, the transparent conductive film for shielding radiation noise may be made of ITO. I
TO has characteristics of resistance and high transmission and is relatively inexpensive, so that it is suitable for use as a transparent conductive film for shielding radiation noise.

According to the method of manufacturing a liquid crystal display device of the present invention, a liquid crystal display device having a liquid crystal display panel having a liquid crystal layer between a front substrate provided on a display surface side and a rear substrate opposed thereto is provided. In the method, a radiation noise blocking transparent conductive film having a thickness of 40 nm or more and 160 nm or less is formed on the display surface of the front substrate, and then, the radiation noise blocking transparent conductive film forming surface of the front substrate is formed. On the other side, a process including etching, for example, a process of forming a metal for a black matrix is performed.

According to the above structure, in the manufacturing method in which the transparent conductive film for blocking radiation noise is formed on the display surface of the front substrate, and then the processing including etching is performed, the thickness of the transparent conductive film for blocking radiation noise is reduced. 40 nm or more, 160 nm
Since the following conditions are satisfied, it is possible to prevent the radiation noise blocking transparent conductive film from peeling off during the etching. In addition, it is possible to prevent a situation in which the transmittance of light is reduced by the transparent conductive film for shielding radiation noise and the display function of the liquid crystal display device is reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. A liquid crystal display device according to one embodiment of the present invention includes a liquid crystal display panel 11 shown in FIG. The liquid crystal display panel 11 has a TFT
A TFT glass substrate (rear substrate) 1 on which a (Thin Film Transistor) is formed, a counter glass substrate (front substrate) 2, and a liquid crystal layer 3 sandwiched therebetween are formed as a basic configuration. A pixel electrode 4 is provided on a surface of the TFT glass substrate 1 facing the counter glass substrate 2, and a counter electrode 5 is provided on a surface of the counter glass substrate 2 facing the TFT glass substrate 1. In addition, a sealing member 6 for sealing the liquid crystal layer 3 is disposed between the TFT glass substrate 1 and the opposing glass substrate 2.

On the side opposite to the surface of the opposite glass substrate 2 on the side of the TFT glass substrate 1, that is, on the display side of the liquid crystal display panel 11 of the opposite glass substrate 2, a transparent conductive film 7 for shielding radiation noise is provided on almost the entire surface. Have been. This transparent conductive film 7 for shielding radiation noise is made of, for example, ITO (Indi
um Tin Oxide) film and formed by vapor deposition.

The liquid crystal display device provided with the liquid crystal display panel 11 has a configuration shown in FIG. In the figure,
A driver IC (drive circuit) 8 for driving the liquid crystal display panel 11 is connected to the liquid crystal display panel 11.

On the transparent electrode film 7 formed on the facing glass substrate 2, a front polarizing plate 12 is adhered. Similarly, a back polarizing plate 13 is adhered to the surface of the TFT glass substrate 1 opposite to the surface facing the opposing glass substrate 2.

The front polarizing plate 12 is formed to be slightly smaller than the transparent conductive film 7 for blocking radiation noise, that is, the counter glass substrate 2. For this reason, the end of the radiation noise blocking transparent conductive film 7 is exposed without being covered by the front polarizing plate 12. The width of the exposed portion 7a is, for example, about 1 mm.
A metal case (conductive case) 15 is adhered to the exposed portion 7 a via a conductive double-sided adhesive tape 14. When the metal case 15 is incorporated in a liquid crystal display device, the metal case 15 is connected to the ground, that is, to the ground via some conductive member. Therefore, the radiation noise blocking transparent conductive film 7 is grounded via the conductive double-sided adhesive tape 14 and the metal case 15.

In the above configuration, the liquid crystal display panel 11
A method of manufacturing the device will be described. When manufacturing the liquid crystal display panel 11, first, the TFT glass substrate 1 and the opposing glass substrate 2 are formed. Then, a light distribution film is formed on the opposing surface of the TFT glass substrate 1 and the opposing glass substrate 2, and an alignment process is performed.

Further, a transparent conductive film 7 for shielding radiation noise is formed on the display surface by sputtering and depositing an ITO film on the opposite glass substrate 2, and an opposite electrode 5 is formed on the opposite surface. Further, a metal for a black matrix is patterned on an opposite glass substrate 2 serving as a metal deposition substrate for a black matrix to form a color filter.

Thereafter, the TFT glass substrate 1 and the opposing glass substrate 2 are bonded to each other, cut into respective panel sizes, and then a liquid crystal material to be the liquid crystal layer 3 is injected and sealed.

As a material for the transparent conductive film 7 for shielding radiation noise, a relatively inexpensive ITO film having characteristics of low resistance and high transmission (high light transmittance) is desirable.

Here, the inventor of the present application has repeated research on the film thickness and sheet resistance of the transparent conductive film 7 for shielding radiation noise.
Those favorable values were obtained. Hereinafter, this will be described.

When the thickness of the transparent conductive film 7 for shielding radiation noise is reduced to less than 40 nm, the transparent conductive film 7 is easily peeled off by an etching process during patterning of the black matrix. That is, this etching process is a wet etching process in which the opposing glass substrate 2 is immersed in an etching solution, so that the transparent conductive film 7 for shielding radiation noise has a thickness of 4 mm.
If it is thin such as less than 0 nm, it will come off.

The transparent conductive film 7 for shielding radiation noise is
If the thickness is less than 40 nm, an alignment film forming / alignment process of the opposite glass substrate 2, a bonding process of the opposite glass substrate 2 and the TFT glass substrate 1, a dividing process of the opposite glass substrate 2, and a transfer and alignment in an inspection process In the case of, for example, the transparent conductive film 7 for blocking radiation noise in the opposite glass substrate 2
When the film-forming surface of the film comes into contact with a manufacturing apparatus, other members, or the like, the film is damaged, and the film is easily peeled off. In addition, when the transparent conductive film 7 for shielding radiation noise is damaged as described above, its resistance value is significantly increased, and a desired function of preventing unnecessary radiation from being blocked cannot be obtained.

Therefore, in the present liquid crystal display device, the thickness of the transparent conductive film 7 for shielding radiation noise is set to 40 nm or more,
In this case, the transparent conductive film 7 for shielding radiation noise is prevented from peeling off. After the front polarizing plate 12 is adhered on the radiation noise blocking transparent conductive film 7, the radiation noise blocking transparent conductive film 7 becomes the front polarizing plate 12.
Therefore, it is possible to prevent the radiation conductive film 7 from being damaged by the above-mentioned mechanical contact or the like.

In the present liquid crystal display device, as described above, the transparent conductive film 7 for shielding radiation noise is formed on the display surface of the opposite glass substrate 2, and the front polarizing plate 12 is adhered thereon. Therefore, when the radiation noise blocking transparent conductive film 7 is thin and less than 40 nm, the radiation noise blocking transparent conductive film 7 may be peeled off at the same time when the front polarizing plate 12 is peeled off in the rework process of the front polarizing plate 12. . In order to prevent such a situation, the thickness of the radiation noise blocking transparent conductive film 7 is set to 40 nm or more.

The rework process of the front polarizing plate 12 is as follows.
If the inspection fails after the front polarizing plate 12 is adhered, the front polarizing plate 12 is peeled off, and another front polarizing plate 1 is again removed.
2 is a step of sticking.

On the other hand, from the viewpoint of optical characteristics, the transparent conductive film 7 for shielding radiation noise provided on the display surface of the opposite glass substrate 2 is used.
Must ensure a predetermined transmittance. Therefore, from this point, it is necessary that the film thickness of the radiation noise blocking transparent conductive film 7 be 160 nm or less. This will be further described below.

FIG. 3 shows the relationship between the thickness of the transparent conductive film 7 for shielding radiation noise and the transmittance of light near visible light. As can be seen from the figure, when the film thickness of the radiation noise blocking transparent conductive film 7 exceeds 160 nm, the transmittance of light having a wavelength of 545 nm is greatly reduced to less than 90%. As a result, the display of the liquid crystal display device becomes dark and does not satisfy the specification of brightness.

That is, the backlight of the liquid crystal display has red (R), green (G), and blue (B) phosphors and emits light. Each phosphor is 610 nm, 545 nm, 435 n
m has a peak wavelength. On the other hand, the color filter is designed so as to match the peak wavelength of each of the R, G, and B colors, and when the visibility is corrected, the transmittance of green (G) increases. Therefore, when the transmittance around 545 nm, which is the emission peak wavelength of green (G), becomes low, the brightness of the liquid crystal display device is impaired. For this reason,
The required transmittance is 90%. That is, the wavelength 545n
When the transmittance of the light of m is less than 90%, the display of the liquid crystal display device becomes dark, and does not satisfy the brightness specification.
Therefore, the film thickness of the radiation noise blocking transparent conductive film 7 is
It is necessary that the thickness be 160 nm or less at which a transmittance of 90% or more is obtained.

Also, from the viewpoint of optical characteristics, when the thickness of the transparent conductive film 7 for blocking radiation noise is less than 40 nm, the contamination on the surface on which the transparent conductive film 7 for blocking radiation noise is formed is enhanced by light interference. As a result, the display quality deteriorates.

From the above viewpoint, in the present liquid crystal display device, the thickness of the transparent conductive film 7 for shielding radiation noise is 40 nm.
At least 160 nm.

In view of the function of blocking unnecessary radiation noise, the transparent conductive film 7 for blocking radiation noise needs to have a low resistance. For example, in the case of a 7-inch liquid crystal display device that is widely used for car navigation at present, the sheet resistance value of the transparent conductive film 7 for blocking radiation noise is 3
If it is not more than 00 Ω / cm ² , the effect of blocking noise will appear. Further, by setting the sheet resistance of the radiation noise blocking transparent conductive film 7 to 60Ω / cm ² or less, it is possible to more effectively block AM band noise.

FIG. 4 shows the relationship between the sheet resistance of the transparent conductive film 7 for blocking radiation noise and the effect of blocking unnecessary radiation noise. The figure shows 100% when the sheet resistance of the transparent conductive film 7 for shielding radiation noise is 10Ω. From the figure,
The sheet resistance of the transparent conductive film 7 for blocking radiation noise is 300Ω / c.
If it exceeds m ² , the noise blocking effect will be 70% or less. In this case, the radiation noise blocking transparent conductive film 7 has no effect as an unnecessary radiation noise blocking film.

FIG. 5 shows the relationship between the sheet resistance and the thickness of the transparent conductive film 7 for shielding radiation noise. When the sheet resistance of the transparent conductive film 7 for blocking radiation noise is 300 Ω / cm ² ,
The film thickness is the lower limit of 40 nm, and the film thickness increases as the sheet resistance decreases. Therefore, it is understood from FIG. 5 that the condition of the sheet resistance and the condition of the film thickness of the transparent conductive film 7 for shielding radiation noise are satisfied with each other.

According to the above configuration, the radiation noise generated in the liquid crystal display device is absorbed by the radiation noise blocking transparent conductive film 7, and is grounded through the exposed portion 7 a at the periphery and the conductive double-sided adhesive tape 14. Dissipated to the metal case 15 (conductive case) having a potential.

Thus, in the present liquid crystal display device, unnecessary radiation noise from the liquid crystal display device can be suppressed by the transparent conductive film 7. Therefore, even when the liquid crystal display device is mounted on an automobile, for example, and the distance between the liquid crystal display device and the antenna of the AM radio cannot be sufficiently secured,
A situation in which unnecessary radiation noise adversely affects the AM radio reception state can be suppressed.

In this case, the radiation noise shielding transparent conductive film 7 is used.
Has a film thickness of not less than 40 nm and not more than 160 nm, so that it is possible to prevent the liquid crystal display device from coming into contact with other objects or peeling off in the etching process in the manufacturing process.
In addition, it is possible to prevent an excessive decrease in light transmittance, and to secure a good display quality.

The transparent conductive film 7 for shielding radiation noise is
Between the opposing glass substrate 2 and the front polarizing plate 12, it is formed on the display surface (front surface) of the opposing glass substrate 2 and included in the liquid crystal display panel 11. Therefore, to connect the radiation noise blocking transparent conductive film 7 to the ground potential, the metal case 15 originally included in the liquid crystal display device can be used, and another grounding member is not required. This allows
Cost increase can be suppressed.

The transparent conductive film 7 for shielding radiation noise is
Since the sheet resistance is 300 Ω / cm ² or less, a good noise cutoff function can be provided.

Further, the present liquid crystal display device has a configuration in which the transparent conductive film 7 for shielding radiation noise is provided between the opposing glass substrate 2 and the front polarizing plate 12, that is, the front surface (display surface) of the opposing glass substrate 2. Since the transparent conductive film 7 for directly blocking radiation noise is provided on the device, a high function of preventing unnecessary radiation noise can be provided. Further, since the anti-reflection treatment may be performed only on the front surface of the front polarizing plate 12 as in the related art, there is no need to change the manufacturing method of the polarizing plate. Therefore,
It is possible to suppress a decrease in productivity and an increase in cost of the polarizing plate, that is, the liquid crystal display device.

Further, when a protective panel having the transparent conductive film 7 for shielding radiation noise is separately provided on the front surface of the liquid crystal display device, dust and dirt accumulate on the front surface of the liquid crystal display device, and the manufacturing process of the liquid crystal display device becomes difficult. Although the workability is reduced and the display quality is reduced during use of the liquid crystal display device, such a situation can be avoided in the present liquid crystal display device.

When the above-mentioned protection panel is provided,
Although the thickness of the liquid crystal display device is increased and its commercial value is impaired, such a situation can be avoided in the present liquid crystal display device.

Next, a liquid crystal display device according to an embodiment of the present invention,
The results obtained by examining the function of blocking unnecessary radiation noise from the liquid crystal display devices of these embodiments with respect to liquid crystal display devices different in the presence / absence and formation position of the transparent conductive film 7 for blocking radiation noise will be described below.

Here, as the liquid crystal display device of the embodiment of the present invention, each of the liquid crystal display panels 11 having the transparent conductive film 7 for shielding radiation noise having a thickness of 40 nm and 100 nm was prepared by different procedures. The liquid crystal display device of No. 3 was used. Further, as a comparative example (reference), a thickness of 30 to
Each liquid crystal display device provided with a 50 μm transparent conductive film on the display surface of the front polarizing plate 12 was used. Further, a liquid crystal display device (normal) not provided with the transparent conductive film 7 for shielding radiation noise was used.

(Embodiment 1) In the liquid crystal display device of this embodiment, first, a surface opposite to the metal deposition surface (a glass to be a display surface) is placed on the opposite glass substrate 2 serving as a metal deposition substrate for black matrix. Surface), an ITO thin film is sputter-deposited on the transparent conductive film 7 for shielding radiation noise.
Was formed.

Next, a metal for a black matrix was patterned on the metal deposition surface of the opposite glass substrate 2 to form a color filter, and thereafter, an opposite electrode 5 was formed.

In the case of this manufacturing method, as described above, since the etching process is performed at the time of patterning the black matrix after the formation of the radiation noise blocking transparent conductive film 7, the radiation noise blocking transparent conductive film 7 is formed. If it is thin, it will come off. Therefore, the thickness of the radiation noise blocking transparent conductive film 7 needs to be 40 nm or more.

According to the above procedure, a liquid crystal display device in which the radiation noise blocking transparent conductive film 7 has a film thickness of 40 nm and 100 nm was prepared.
The blocking function of unnecessary radiation noise in each frequency band of 10 MHz (all regions), 70 to 110 MHz (FM region), and 500 to 1000 kHz (AM region) was evaluated. In addition, the evaluation results were compared with the reference and normal ones.

As a result, as shown in Table 1, in the unnecessary radiation noise blocking function, the liquid crystal display device provided with the radiation noise blocking transparent conductive film 7 includes the radiation noise blocking transparent conductive film including the reference one. 7 was better than the normal one that did not have 7. When the transparent conductive film 7 for blocking radiation noise had a thickness of 100 nm, a more excellent function of blocking unnecessary radiation noise was obtained in the AM region (500 to 1000 kHz).

In this embodiment, the order of forming the radiation noise blocking transparent conductive film 7 and the counter electrode 5 is as follows.
First, a radiation noise blocking transparent conductive film 7 is formed, and thereafter, a counter electrode 5 is formed. Hereinafter, advantages of this forming procedure will be described.

IT to be a transparent conductive film 7 for shielding radiation noise
The O film has a disadvantage that the stain on the base is emphasized by interference. The transparent conductive film 7 for shielding radiation noise is
Since it is located on the display surface side of the liquid crystal display device, the above-mentioned disadvantages have a great effect. However, when the transparent conductive film 7 for shielding radiation noise is formed before the counter electrode 5, the transparent conductive film 7 can be formed on the counter glass substrate 2 immediately after cleaning. In this case, it is difficult to cause stains on the base of the transparent conductive film 7 for shielding radiation noise, that is, the counter glass substrate 2, unevenness in film formation due to the presence of foreign matter on the film formation surface, and the like, resulting in deterioration of display quality. It can be suppressed.

On the other hand, in the procedure in which a color filter is formed on the opposite glass substrate 2, the opposite glass substrate 2 is formed, and then the transparent conductive film 7 for shielding radiation noise is formed, the radiation noise on the opposite glass substrate 2 is reduced. There is a possibility that a residue due to etching or the like in the color filter forming step may be present on the deposition surface of the blocking transparent conductive film 7. If such a residue is present, contamination of the base and unevenness in the formation of the transparent conductive film 7 for shielding radiation noise occur, which leads to a reduction in display quality. On the other hand, if the opposing glass substrate 2 is cleaned before forming the radiation noise blocking transparent conductive film 7 in order to suppress such a situation, the number of steps will be increased.

When the transparent conductive film 7 for blocking radiation noise is formed on one surface of the opposite glass substrate 2 and the opposite electrode 5 is formed on the other surface,
The one formed earlier is more likely to be damaged when the opposing glass substrate 2 is transported or the like. Here, the effects on the liquid crystal display device when the transparent conductive film 7 for shielding radiation noise and the counter electrode 5 are damaged will be compared. If the opposing electrode 5 is damaged, conduction between the pixel portions is interrupted, and lighting failure of the pixel portion occurs. On the other hand, if the transparent conductive film 7 for shielding radiation noise is damaged,
It hardly affects the function of blocking unnecessary radiation noise.
Therefore, from such a point as well, it is preferable to form the radiation noise blocking transparent conductive film 7 first, and then form the counter electrode 5 as the procedure for forming both.

(Embodiment 2) In the liquid crystal display device of this embodiment, a color filter and a black matrix of three colors are formed on a counter glass substrate 2 and a counter electrode 5 is further formed. A transparent conductive film 7 for shielding radiation noise was formed on the display surface of the opposite glass substrate 2 on the opposite side. The liquid crystal display device has the same structure as the liquid crystal display device of the first embodiment, although the forming procedure is different.

According to the above-described procedure, a liquid crystal display device in which the thickness of the transparent conductive film 7 for blocking radiation noise is 40 nm and 100 nm is prepared, and this liquid crystal display device is similarly blocked for unnecessary radiation noise in each frequency band. Function was evaluated.

As a result, as shown in Table 1, similar to the case of the first embodiment, the liquid crystal display device of the present embodiment has a better unnecessary radiation noise blocking function than the normal type. The thickness of the transparent conductive film 7 for blocking radiation noise is 10
In the case of 0 nm, the AM region (500 to 1000 kHz)
Was even better.

(Embodiment 3) In the liquid crystal display device of this embodiment, first, a color filter of three colors and a black matrix are formed on the opposing glass substrate 2, and then the transparent conductive film 7 for blocking radiation noise and the opposing glass are formed. A radiation noise blocking transparent conductive film for the electrode 5 was formed. Further, first, a color filter of three colors and a black matrix are formed, and then, a transparent conductive film 7 for shielding radiation noise is formed.
A transparent conductive film for the counter electrode 5 was formed.

That is, in the present embodiment, the formation of the radiation noise blocking transparent conductive film 7 was performed in the following two procedures. First, a color filter and a black matrix of three colors were formed on the opposing glass substrate 2, and then a transparent conductive film 7 for shielding radiation noise and a transparent conductive film for the counter electrode 5 were simultaneously formed by vapor deposition. First, a color filter and a black matrix of three colors were formed on the opposite glass substrate 2, a transparent conductive film 7 for shielding radiation noise was formed, and then a transparent conductive film for the opposite electrode 5 was formed.

The liquid crystal display device of the present embodiment is different from the liquid crystal display device of the first embodiment in the forming procedure, but has the same structure.

By the above-described procedures, a liquid crystal display device in which the thickness of the transparent conductive film 7 for blocking radiation noise is 40 nm and 100 nm is prepared, and this liquid crystal display device is similarly subjected to unnecessary radiation noise in each frequency band. The blocking function was evaluated.

As a result, as shown in Table 1, similar to the case of the first embodiment, the liquid crystal display device of the present embodiment has a better unnecessary radiation noise blocking function than the normal type. The thickness of the transparent conductive film 7 for blocking radiation noise is 10
In the case of 0 nm, the AM region (500 to 1000 kHz)
Was even better.

[0075]

[Table 1]

From the results shown in Table 1, in the liquid crystal display devices of Examples 1 to 3 and the reference liquid crystal display device in which the order of forming the transparent conductive film 7 for blocking radiation noise is good, and the same level of unnecessary radiation noise blocking function is used. was gotten. Further, in Examples 1 to 3, in the liquid crystal display device in which the thickness of the transparent conductive film 7 for blocking radiation noise was 100 nm, a better unnecessary radiation noise blocking function was obtained in the AM region.

[0077]

As described above, the liquid crystal display device of the present invention comprises a liquid crystal display panel in which a liquid crystal layer is provided between a front substrate provided on the display surface side and a rear substrate opposed thereto. And a transparent conductive film for blocking radiation noise formed on the display surface of the front substrate having a thickness of 40 nm or more and 160 nm or less.

According to the above configuration, since the transparent conductive thin film is formed directly on the display surface (front surface) of the front substrate, it can have a high protection function against unnecessary radiation noise from the liquid crystal display panel. .

Further, the transparent conductive film for shielding radiation noise
Since it is formed not on the surface of the front polarizing plate but on the display surface of the front substrate, the anti-reflection treatment is applied to the surface of the front polarizing plate. The anti-reflection function of the is not impaired.

Further, since the radiation noise blocking transparent conductive film is set to have a thickness of 40 nm or more, the radiation noise blocking transparent conductive film formed on the front substrate during manufacturing of the liquid crystal display device is made of another material. Damage due to friction when it comes into contact with the device, further peeling, excessive damage due to scratching, the ability to absorb unnecessary radiation noise is significantly reduced, or etching during the manufacturing process of the liquid crystal display device It is possible to prevent a situation such as peeling due to processing.
Further, when the film thickness is less than 40 nm, the contamination on the film forming surface of the transparent conductive film for shielding radiation noise is emphasized by light interference and the display quality deteriorates. However, since the film thickness is 40 nm or more, Such a situation can also be prevented.

The radiation noise blocking transparent conductive film has a thickness set to 160 nm or less, so that the light transmittance at the time of display can be maintained in a favorable range. A situation in which the display function of the liquid crystal display device is reduced can be prevented.

The transparent conductive film for shielding radiation noise is formed on the display surface (front surface) of the front substrate, and has a configuration included in the liquid crystal display panel. Therefore, in order to connect the radiation noise blocking transparent conductive film to the ground potential, a conductive casing or the like originally provided in the liquid crystal display device can be used,
No additional grounding member is required. Thereby, cost increase can be suppressed.

In the above liquid crystal display device, the transparent conductive film for shielding radiation noise may have a surface resistance of 300 Ω / cm ² or less.

According to the above configuration, since the transparent conductive film for shielding radiation noise has a sheet resistance of 300 Ω / cm ² or less, it can have a good blocking function for unnecessary radiation noise.

In the liquid crystal display device described above, the transparent conductive film for shielding radiation noise may have a surface resistance of 60 Ω / cm ² or less.

According to the above configuration, the radiation noise shielding transparent is provided.
The bright conductive film has a sheet resistance of 60Ω / cm. ^TwoSince
Furthermore, AM band noise can be better blocked.
You.

The liquid crystal display device described above may have a structure in which a polarizing plate is provided on the front surface of the radiation noise blocking transparent conductive film.

According to the above configuration, in the configuration in which the polarizing plate is provided on the display surface side of the front substrate of the liquid crystal display panel, the transparent conductive film for shielding radiation noise is not formed on the surface of the polarizing plate. In other words, the anti-reflection treatment may be performed only on the front surface as in the related art. Therefore, there is no need to change the manufacturing method of the polarizing plate, and it is possible to suppress a decrease in productivity and an increase in cost of the polarizing plate, that is, the liquid crystal display device.

In the above liquid crystal display device, the transparent conductive film for shielding radiation noise may be made of ITO. I
TO has characteristics of resistance and high transmission and is relatively inexpensive, so that it is suitable for use as a transparent conductive film for shielding radiation noise.

The method of manufacturing a liquid crystal display device according to the present invention is directed to a method of manufacturing a liquid crystal display device having a liquid crystal display panel having a liquid crystal layer provided between a front substrate provided on a display surface side and a rear substrate opposed thereto. In the method, a radiation noise blocking transparent conductive film having a thickness of 40 nm or more and 160 nm or less is formed on the display surface of the front substrate, and then, the radiation noise blocking transparent conductive film forming surface of the front substrate is formed. On the other side, a process including etching is performed.

According to the above configuration, in the manufacturing method in which the transparent conductive film for shielding radiation noise is formed on the display surface of the front substrate and then the processing including etching is performed, the thickness of the transparent conductive film for shielding radiation noise is reduced. 40 nm or more, 160 nm
Since the following conditions are satisfied, it is possible to prevent the radiation noise blocking transparent conductive film from peeling off during the etching. In addition, it is possible to prevent a situation in which the transmittance of light is reduced by the transparent conductive film for shielding radiation noise and the display function of the liquid crystal display device is reduced.

[Brief description of the drawings]

FIG. 1 is a side view showing a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a liquid crystal display panel included in the liquid crystal display device shown in FIG.

FIG. 3 is a graph showing a relationship between a light wavelength and a light transmittance at each film thickness of the radiation noise blocking transparent conductive film shown in FIG.

FIG. 4 is a graph showing a relationship between a sheet resistance and a noise blocking effect in the radiation noise blocking transparent conductive film shown in FIG.

FIG. 5 is a graph showing a relationship between a film thickness and a sheet resistance in the radiation noise blocking transparent conductive film shown in FIG.

FIG. 6 is a side view showing a configuration of a conventional liquid crystal display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 TFT glass substrate (rear substrate) 2 opposing glass substrate (front substrate) 3 liquid crystal layer 4 pixel electrode 5 opposing electrode 7 transparent conductive film for shielding radiation noise 11 liquid crystal display panel 12 front polarizer 13 back polarizer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA37X FA50X FB06 FC03 FC25 FC29 GA16 LA30 2H092 GA64 KB05 MA04 MA35 NA25 NA30 PA06 5C094 AA43 AA44 AA45 BA03 BA43 CA19 DA13 EA04 EA05 EA07 EB02 ED15 JA08 JA11

Claims (6)

[Claims] 1. A liquid crystal display panel having a liquid crystal layer provided between a front substrate provided on a display surface side and a rear substrate opposed thereto, and a liquid crystal display panel formed on the display surface of the front substrate and having a film thickness. 40n
a transparent conductive film for shielding radiation noise of not less than m and not more than 160 nm. 2. The liquid crystal display device according to claim 1, wherein the transparent conductive film for blocking radiation noise has a sheet resistance of 300 Ω / cm ² or less. 3. The radiation noise blocking transparent conductive film has a sheet resistance of 60 Ω / cm ² or less.
3. The liquid crystal display device according to 1. 4. The liquid crystal display device according to claim 1, wherein a polarizing plate is provided on a front surface of the radiation noise blocking transparent conductive film. 5. The transparent conductive film for shielding radiation noise is made of ITO.
The liquid crystal display device according to claim 1, comprising: 6. A method of manufacturing a liquid crystal display device having a liquid crystal display panel having a liquid crystal layer provided between a front substrate provided on a display surface side and a rear substrate facing the front substrate, wherein the display on the front substrate is performed. The surface has a film thickness of 40 nm or more,
Forming a radiation noise blocking transparent conductive film of 160 nm or less, and thereafter, performing a process including etching on a surface of the front substrate opposite to the surface on which the radiation noise blocking transparent conductive film is formed. Of manufacturing a liquid crystal display device.