JPH0850281A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To obtain such a display device that liquid crystal molecules can be moved into different states when voltage is applied and the angle of visual field can be enlarged by forming a voltage controlling film having a region with different dielectric const. on a conductive film. CONSTITUTION:Displaying is performed by applying voltage between a conductive film 13 and another conductive film on the opposite side of a liquid crystal 17 to the conductive film 13 so as to move liquid crystal molecules of the liquid crystal 17. In this method, a region 14a, 14b having different dielectric const. is formed in an insulating film 14 so that even when voltage is applied, effective voltage applied on the liquid crystal molecules differs according to regions. Namely, since the dielectric const. in the region 14a, 14b, is higher than other region, relatively larger voltage is applied on the liquid crystal molecules in the region 14a, 14b compared with the rest of molecules. Therefore, compared with the tilt angle A of liquid crystal molecules in the region 14a, 14b, tilt angle B of liquid crystal molecules in other region is made smaller. Thus, the angle of visual field is enlarged in the liquid crystal display device.

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,
In particular, the present invention relates to a liquid crystal display device in which the structure of a layer formed between a liquid crystal and a conductive film for applying a voltage to the liquid crystal is improved.

[0002]

2. Description of the Related Art Conventionally, various liquid crystal display devices such as an active matrix type liquid crystal display device, a TN type liquid crystal display device, and a liquid crystal display device using a ferroelectric liquid crystal are known. An example of the structure of the display portion of such a liquid crystal display device is shown in FIG.

In the liquid crystal display device 1, the liquid crystal 4 is injected between the substrates 2 and 3 made of a transparent material such as glass. On the surfaces of the substrates 2 and 3 on the liquid crystal 4 side, transparent conductive films 5 and 6 and alignment films 7 and 8 which function as electrodes for applying a voltage to the liquid crystals are formed. The transparent conductive films 5 and 6 are made of, for example, ITO (indium tin oxide), while the alignment films 7 and 8 are made of synthetic resin such as polyimide. The alignment films 7 and 8 are provided to make the initial alignment of the liquid crystal molecules uniform, thereby improving the display characteristics.

Although not shown in the drawing, for example, in an active matrix type liquid crystal display device, a thin film transistor for driving pixels is formed in a portion not shown, and in a color liquid crystal display device,
A color filter and the like for performing color display are configured.

[0005]

By the way, in the liquid crystal display device 1, since the alignment films 7 and 8 made of a single material are formed on the conductive films 5 and 6 as described above, the initial liquid crystal molecules are not formed. Although the alignment state is made uniform, the liquid crystal molecules move uniformly when a voltage is applied. That is, when a voltage equal to or higher than a certain threshold voltage is applied, the liquid crystal molecules on the alignment film 8 move uniformly, and as a result, the viewing angle tends to be narrowed.

It is an object of the present invention to provide a liquid crystal display device which allows liquid crystal molecules to move differently when a voltage is applied, thereby expanding the viewing angle.

[0007]

The present invention is a liquid crystal display device having a liquid crystal and a conductive film for applying a voltage to the liquid crystal, and has regions formed on the conductive film and having different dielectric constants. A liquid crystal display device having an applied voltage adjusting film.

That is, in the liquid crystal display device of the present invention, the applied voltage adjusting film having regions having different permittivities is formed on the conductive film functioning as an electrode. Therefore, a voltage is applied from the conductive film to the liquid crystal. In that case, the voltage actually applied to the liquid crystal molecules varies depending on the region. As a result, the threshold voltage for moving the liquid crystal varies depending on the region, so that the movement of the liquid crystal varies depending on the region and the viewing angle is expanded.

As described above, various modes are conceivable for forming the regions having different dielectric constants in the film formed on the conductive film. For example, the applied voltage adjusting film,
It is configured by a laminated film of an alignment film and at least one insulating film arranged between the alignment film and the conductive film, and at least one of the alignment film and the insulating film has a region having a different dielectric constant. You may comprise.

Further, the applied voltage adjusting film is an alignment film,
A laminated film of at least one insulating film, both the alignment film and the insulating film have regions having different dielectric constants, and the regions having different dielectric constants of the alignment film and the insulating film partially overlap each other. It may be configured such that regions of different dielectric constants are formed in the applied voltage adjusting film in multiple stages.

Further, the applied voltage adjusting film in the liquid crystal display device of the present invention may also serve as an alignment film.
That is, in a liquid crystal display device in which an alignment film is formed on a conductive film and liquid crystals are arranged on the alignment film, a plurality of regions having different dielectric constants are formed in the alignment film, and the voltage applied to the alignment film is thereby increased. It may also provide the function of a conditioning film.

Further, in the method of manufacturing a liquid crystal display device of the present invention, in manufacturing a liquid crystal display device having a conductive film for applying a voltage to liquid crystal, after the conductive film is formed, a dielectric constant is formed on the conductive film. It is characterized in that an applied voltage adjusting film having different regions is formed.

The applied voltage adjusting film can be formed by various methods. For example, in forming an applied voltage adjustment film having an alignment film and at least one insulating film disposed between the alignment film and the conductive film, by irradiating at least one of the alignment film and the insulating film with a laser, The regions having different dielectric constants may be formed, or the regions having different dielectric constants may be formed by performing ion implantation with a mask on at least one of the alignment film and the insulating film. At least one of the insulating film and the insulating film may be irradiated with an energy beam and partially annealed to form regions having different dielectric constants.

[0014]

In the liquid crystal display device of the present invention, the applied voltage adjusting film having the regions having different permittivities as described above is formed on the conductive film. Therefore, when a voltage is applied to the liquid crystal from the conductive film, the applied voltage adjusting film has regions having different permittivities, so that the voltage is not uniformly applied to the liquid crystal and different voltages are applied to the regions. .

Therefore, when a voltage higher than the threshold voltage at which the liquid crystal starts to move is applied, the liquid crystal molecules on the applied voltage adjusting film do not move uniformly. Therefore, the viewing angle of the liquid crystal display device can be expanded.

In the case where regions having different dielectric constants are formed in the applied voltage adjusting film in one pixel as described above, the voltages applied to the liquid crystal molecules are different depending on the regions. It is also possible to perform gradation display by utilizing the voltage difference applied to the molecules.

The applied voltage adjusting film is an alignment film,
At least one insulating film is provided, regions having different dielectric constants are provided in both the alignment film and the insulating film, and regions having different dielectric constants of the alignment film and the insulating film are partially overlapped, In the applied voltage adjusting film, regions having different dielectric constants in multiple stages are formed. As a result, when a voltage is applied to the liquid crystal from the conductive film, the movement of the liquid crystal molecules can be made more uneven depending on the region, and thus the viewing angle can be further expanded.

In particular, when the structure in which the regions having different dielectric constants are formed is applied to one pixel, it is possible to perform finer gradation display.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by describing embodiments of the present invention. FIG. 2 shows the first of the present invention.
FIG. 3 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device according to the example of FIG. In the liquid crystal display device 11, a conductive film 13 is formed on a translucent substrate 12 made of glass or translucent synthetic resin. An insulating film 14 is formed on the conductive film 13.
And the alignment film 15 are laminated in this order, and the applied voltage adjusting film 16 is composed of the insulating film 14 and the alignment film 15. Liquid crystal 17 is injected on the alignment film 15.

Although not shown in particular, a substrate on which a conductive film and an alignment film are further formed with an insulating film, if necessary, is arranged above the liquid crystal 17, and the substrate and the substrate 12 are provided. The liquid crystal 17 is injected between them.

The conductive film 13 functions as an electrode for applying a voltage to the liquid crystal 17, and is made of a transparent conductive material such as ITO. Conductive film 13
In this embodiment, the insulating film 14 formed above is made of Ti.
It consists of O ₂ . However, the insulating film 14 may be made of another insulating material such as SiN.

The insulating film 14 is not formed uniformly and has a plurality of regions 14 having a dielectric constant different from that of the remaining regions.
a and 14b are formed. Relative permittivity ε of TiO ₂ film
Is 96, whereas in the present embodiment, the regions 14a, 1
Areas 14a, 1 containing SiO ₂ in areas other than 4b
The dielectric constant of 4b is relatively increased. That is, S
The relative permittivity of iO ₂ is ε = 3.78, and therefore the S
By adjusting the content of iO _2, the regions 14a, 14
The dielectric constant of regions other than b is lowered.

A plurality of regions 14a, 1 having different dielectric constants
4b is formed by, for example, forming a TiO ₂ film and then forming a region 1
This can be performed by covering the regions 4a and 14b with a mask made of, for example, a resist resin, and implanting Si ions into the regions other than the regions 14a and 14b.

In this embodiment, the TiO ₂ film is used as the insulating film, but in addition to TiO ₂ , PbO, Al ₂ O ₃ and Ba are used in addition to SiO ₂ used in a preferred modification described later.
TiO ₃ , KNbO ₃ , BaTiO ₃ system PbTiO ₃ ,
LiNbO _3, LiTaO ₃ or the like may constitute the insulating film.

The alignment film 15 is formed in the region 14 having a different dielectric constant.
formed on the insulating film 14 after forming a and 14b,
For example, it is made of an appropriate material such as a polyimide resin which has been conventionally used as an alignment film material in a liquid crystal display device.

In the liquid crystal display device 11 of the first embodiment, a voltage is applied from the conductive film 13 and the conductive film disposed on the opposite side of the conductive film 13 via the liquid crystal 17, and the liquid crystal molecules of the liquid crystal 17 are separated. It is moved and displayed. In this case, the insulating film 1
Since the regions 14a and 14b having different permittivities are formed in No. 4, even if a voltage is applied, the actual voltage applied to the liquid crystal molecules varies depending on the region. That is, since the regions 14a and 14b have a higher dielectric constant than the remaining regions, a relatively large voltage is applied to the liquid crystal molecules on the regions 14a and 14b compared to the liquid crystal molecules on the remaining regions. It Therefore, as shown schematically in FIG.
The inclination B of the liquid crystal molecules on the remaining regions is smaller than the inclination A of the liquid crystal molecules on the regions 14a and 14b.
Therefore, the viewing angle in the liquid crystal display device 11 can be expanded.

When the applied voltage adjusting film 16 is formed so as to have the regions 14a and 14b having different dielectric constants in one pixel as described above, the liquid crystal molecules are actually formed in one pixel by the region. Since the applied voltage is changed, gradation display can also be performed by utilizing the voltage difference applied to the liquid crystal molecules.

Next, a preferred modification of the first embodiment will be described. In the first embodiment, the insulating film 14 is made of a TiO ₂ film, and SiO ₂ is contained in a portion other than the regions 14a and 14b of the insulating film 14 to lower the dielectric constant of the regions other than the regions 14a and 14b. At the same time, the dielectric constants of the regions 14a and 14b were relatively increased. On the other hand, in a preferred modified example described below, the insulating film 14 has a relative dielectric constant ε =
A SiO ₂ film of 3.78 is formed, and ε = 9 is formed on the SiO ₂ film.
TiO ₂ The area 14a of the 6, characterized in that is contained in 14b. The other structure is exactly the same as that of the first embodiment. Therefore, the description of each component used in the first embodiment will be cited, and only different parts will be described.

In a preferred modification, contrary to the first embodiment, the regions 14a, 14 of the insulating film 14 made of a SiO ₂ film are formed.
b contains TiO ₂ , whereby the regions 14a,
14b has a higher dielectric constant, while regions 14a, 14b
The dielectric constant of the region other than is relatively low. The reason why this modification is preferable to the first embodiment is that the relative permittivity of the injected TiO ₂ is ε = 96, which is much higher than the relative permittivity ε = 3.78 of the SiO ₂ film. This is because the effect of adjusting the dielectric constant is large due to the inclusion of TiO ₂ .

Next, a concrete experimental result in the preferable modification will be described. As the insulating film 14, a thickness of 3000
A Å SiO ₂ film is formed, and then the regions 14a, 14 are formed.
In step b, Ti ions are implanted and TiO ₂ is added to the region 14
a, 14b. As a result, the regions 14a, 14
The region other than b is ε = 3.78, while the region 14
ε of a and 14b became 8. Further, as the alignment film 15, a film made of a polyimide resin having a thickness of 0.1 μm (ε =
3) was formed into a film. Furthermore, the insulating film 14 and the alignment film 1
Substrate 12 on which applied voltage adjusting film 16 of 5 is formed
Was used to manufacture a liquid crystal display device having a cell gap of 5 μm.

In the liquid crystal display device manufactured as described above, when a voltage of 5 V is applied, the liquid crystal cell located above the regions 14a and 14b and the liquid crystal cell located above the regions other than the regions 14a and 14b. It was confirmed that the applied voltage difference between and was about 0.85V.

For example, when displaying 8 gradations with an applied voltage difference of 1.75V, an applied voltage difference of 0.25V is required for each gradation. Therefore, it can be seen that the applied voltage difference of 0.85 V makes it possible to obtain the applied voltage difference of 3 to 4 gradations. Therefore, as is apparent from the above modification, the insulating film 14 is provided with regions 14a and 14b having a relatively high dielectric constant and other regions having a relatively low dielectric constant to adjust the dielectric constant difference. Therefore, it is understood that various gradation display can be performed.

In the above experimental example, Ti ions are implanted in the regions 14a and 14b to have a relative permittivity ε = 8, and ε = 3.7 in other regions consisting of SiO ₂ only.
8 and the relative dielectric constant difference of 4.22 were provided.
By the way, the relative permittivity difference between the region having a relatively high dielectric constant and the region having a relatively low dielectric constant is calculated by considering a configuration including one alignment film, a liquid crystal, the other alignment film and an insulating film as a series capacitance. From the above experimental results, when the dielectric constant difference is 1,
It can be seen that the difference between the applied voltage applied to the liquid crystal above the region having a relatively high dielectric constant and the applied voltage applied to the liquid crystal located above the region having a relatively low dielectric constant is 0.264V. Therefore, when the relative dielectric constant difference between the regions having different dielectric constants is 1, the voltage difference of 0.
Since it exceeds 25 V, it is considered that it can function as an applied voltage adjusting film for gradation display.

However, the steepness of the rising region of the VT characteristic differs depending on the liquid crystal material, and in the liquid crystal material having high steepness, the difference in applied voltage required for one gradation is small.
Therefore, depending on the liquid crystal material, it is considered that gradation display can be performed even if the relative dielectric constant difference between the region having a relatively high dielectric constant and the region having a relatively low dielectric constant is 1 or less. Therefore, in the above experimental example, a region having a relatively high relative dielectric constant,
It is considered that the relative dielectric constant difference with the relatively low region is required to be at least about 1 in order to perform gradation display, but it is not necessarily limited to this value, and the ratio at which gradation display is possible is possible. It suffices to determine the relative dielectric constant difference between the region having a relatively high dielectric constant and the region having a relatively low dielectric constant so as to have the dielectric constant difference.

FIG. 8 is a diagram showing the relationship between the viewing angle and the contrast ratio in the active matrix type liquid crystal display device manufactured based on the above-described preferable modification.
In FIG. 8, □ indicates the result of the above modification. In addition, in addition to the above modified example, Δ is also applied to the alignment film.
The result of the 2nd modification which comprised the area | region where a dielectric constant differs relatively is shown. In addition, ◯ indicates the result in the conventional active matrix type liquid crystal display device having the same configuration except that the applied voltage adjusting film is not provided.

As is apparent from FIG. 8, compared with the conventional example,
It can be seen that in the preferable modified example and the second modified example, the contrast is enhanced over a wide viewing angle, particularly at a low viewing angle (0 ° to + 60 °). On the other hand, in the conventional example, the contrast is high only when the viewing angle is in the vicinity of 0 °, and the contrast remarkably decreases as the viewing angle shifts.

Further, in the conventional example, the viewing angle at which the display is reversed and the original white display becomes black is -30 °, whereas in the conventional example, the preferable modification and the first preferred embodiment embodying the present invention. It can be seen that in the second modified example, the widths are as wide as −40 ° and −50 °, respectively.

Therefore, it is understood that the viewing angle can be effectively widened by providing the applied voltage adjusting film. FIG.
FIG. 6 is a schematic cross-sectional view for explaining a liquid crystal display device according to a second embodiment of the present invention. In the liquid crystal display device 21 of the second embodiment, the conductive film 13 is formed on the substrate 12, and the applied voltage adjusting film 26 including the insulating film 14 and the alignment film 25 is laminated on the conductive film 13. There is. The liquid crystal 17 is injected on the applied voltage adjustment film 26. Also in this embodiment, a substrate on which an alignment film and a conductive film are further formed on the liquid crystal 17 side and, if necessary, an insulating film is arranged above the liquid crystal 17.

The difference between the second embodiment and the first embodiment is that a plurality of regions 2 having different dielectric constants are formed in the alignment film 25.
5a to 25c are formed. The relative permittivity of the regions 25a to 25c having different permittivities is relatively higher than that of the remaining regions of the alignment film 25. The regions 25a to 25c are formed so as to partially overlap the regions 14a and 14b of the insulating film 14 in which the dielectric constant is relatively increased. Since the other points are the same as those of the liquid crystal display device 11 of the first embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, since the regions 25a to 25c having different permittivities are also formed in the alignment film 25, the voltage applied to the liquid crystal is different when the applied voltage adjusting film 26 is viewed as a whole. Two areas will be constructed. That is, from the highest voltage applied to the liquid crystal,
Regions 25a to 25c and regions 14a and 14b overlap, regions 14a and 14b are formed, and regions 25a to 25c do not overlap, regions 25a to 25c are formed. Areas that do not overlap with the areas 14a and 14b, areas 25a to 25c, and areas 14a and 14
The order is the region in which b is not formed.

Therefore, in the liquid crystal display device 21 of this embodiment, when a voltage is applied between the conductive film 13 and the conductive film on the other side, the voltage actually applied to the liquid crystal molecules is one of the above four types. It depends on the area. That is, since the larger applied voltage is applied in the order of the regions shown in the above, and therefore the movement of the liquid crystal molecules is different depending on the region even when the voltage higher than the threshold voltage is applied, the first embodiment The viewing angle can be expanded similarly to the example, and since the movement of the liquid crystal molecules can be adjusted in multiple stages as compared with the first embodiment, the viewing angle can be further expanded.

As described above, since the four types of regions (1) to (4) are provided in the applied voltage adjusting film 26, the four types of regions as described above are formed in one pixel to realize the first embodiment. It is also possible to perform finer gradation display than in the example.

As a method of forming the regions 25a to 25c having a relatively high dielectric constant in the alignment film 25,
The mask stack in the first embodiment described above is used.
In addition, in the first embodiment, a method of laminating a mask on an insulating film and performing ion implantation in forming a region having a relatively high dielectric constant has been described. It is also possible to form high or low areas. For example, the insulating film may be irradiated with laser to form regions having different dielectric constants, or the insulating film may be partially thermally annealed to form regions having different dielectric constants.

In the first embodiment, the insulating film 14 is provided with regions 14a and 14b having different permittivities, and in the second embodiment, both the insulating film 14 and the alignment film 25 are provided with regions having different permittivities. Although provided, a region having a different dielectric constant may be provided only on the alignment film side.

In the structure in which only the alignment film is formed without using an insulating film, the applied voltage adjusting film of the present invention also serves as the alignment film by forming regions having different dielectric constants in the alignment film. It may be configured as follows. As a method of forming such an alignment film, for example, a method of mixing a plurality of alignment film materials having different dielectric constants and spin-coating can be mentioned.

In the first and second embodiments, one insulating film 1 is used.
4 was formed on the conductive film 13, but in the present invention, 2 is formed.
The above insulating film may be formed on the conductive film 13,
In that case, regions having different dielectric constants are formed in at least one insulating film. In addition, preferably, by forming a plurality of insulating films having regions having different dielectric constants and arranging the regions having different dielectric constants so as to partially overlap each other,
Regions having different dielectric constants may be formed in more steps in the applied voltage adjusting film.

In the first and second embodiments, in order to explain the function of the applied voltage adjusting films 16 and 26, the applied voltage adjusting film is explained by the cross-sectional view along the thickness direction of the liquid crystal display device.
The planar shape of the regions having different dielectric constants can be arbitrarily changed as necessary. Modified examples of such regions having different permittivities will be described with reference to FIGS.

FIG. 4A is a plan view showing a plane shape of regions having different dielectric constants when regions having different dielectric constants are formed in one pixel. In the example shown in FIG. 4A, in the pixel 31, the region 3 having the highest dielectric constant is used.
1A is formed in the shape of a stripe in the center, and on both sides thereof, a band-like region 31 having a lower dielectric constant than the region 31A is formed.
B and 31C are formed. In addition, the regions 31B and 31
Regions 31D and 31E having the lowest dielectric constant are formed outside C. This structure can be formed, for example, by forming the regions 31A to 31E in the insulating film 14 in the first embodiment. That is, it can be configured by forming a region having the highest permittivity, a region having an intermediate permittivity, and a region having the lowest permittivity in the insulating film 14. Alternatively, in the second embodiment, a region having a higher dielectric constant than the remaining region is formed so as to be located in the region 31A on the alignment film 25 side, and the regions 31A to 31C are formed on the insulating film 14 side. It can be configured by forming a region having a relatively high dielectric constant in the corresponding region.

As described above, the five regions 31A to 31E shown in FIG. 4A are regions 14a having different permittivities in the regions provided on the insulating film 14 and different permittivities provided in the insulating film 14 and the alignment film 25. , 14b, 25a to 25c can be appropriately achieved by devising the arrangement.

Similarly, in the example shown in FIG. 4B, regions 32A and 32B having a relatively high dielectric constant are provided in the pixel 32.
Is formed in a stripe shape and has a relatively low dielectric constant between the regions 32A and 32B.
However, a region 32D having a relatively low dielectric constant is also formed on the opposite side of the region 32A from the region 32C. Each area 3
2A to 32D are all configured to have the same width, but this width can also be changed as appropriate to achieve the target gradation display.

Also in the example shown in FIG. 4B, the regions 32A and 32B are, for example, the regions 14a and 14b provided in the insulating film 14 in the first embodiment.
It can be configured by forming it so as to correspond to A and 32B. In addition, the regions 32A, 3 are provided on the alignment film side.
A region having a relatively high dielectric constant may be formed so as to correspond to 2B.

The first and second embodiments described above and FIG.
In the configurations of (a) and (b), only a portion where the applied voltage adjusting film is provided is schematically shown, and another specific configuration when configuring the liquid crystal display device, for example, an active matrix liquid crystal display device. Although the physical positional relationship with a transistor or the like in the case of configuring the above has been omitted, an example of such a configuration will be described as an example with reference to FIGS. 7A and 7B. To do.

FIGS. 7A and 7B are a plan view and a partial cutout for explaining a main part of an active matrix type liquid crystal display device in which an applied voltage adjusting film is formed in the pattern of FIG. 4B. FIG.

As shown in FIG. 7A, on the substrate of the active matrix type liquid crystal display device in which the applied voltage adjusting film is formed in the pattern shown in FIG. 4B, the ITO film for forming pixels is used. The substantially rectangular transparent display electrode 41 is formed, and the gate lines 42 and 43 and the drain line 44 pass laterally of the display electrode 41.

Further, as is clear from FIG. 7B, which corresponds to the portion along the line BB of FIG. 7A and shows the sectional structure after the applied voltage adjusting film is formed, the display electrode 41 is formed. The insulating film 45 and the alignment film 46 are laminated. The insulating film 45 corresponds to the insulating film 14 in the first embodiment, and is configured to have regions 45a and 45b having a relatively high dielectric constant and the remaining regions having a relatively low dielectric constant inside. Has been done. That is, the region 45 having a relatively high dielectric constant is
a and 45b correspond to the areas 32a and 32b shown in FIG.

Further, in FIG. 7B, 47 is a source electrode for forming a thin film transistor, 48 is a drain electrode, and 49 is a gate electrode. Also, 50,5
Reference numeral 1 is a contact portion for electrically connecting the source electrode 47 and the drain 48 to the display electrode 41 and the drain line, respectively. Further, below the gate electrode 49,
The insulating film 52 is formed.

In the portion where the TFT for driving the pixel as described above is formed, as is apparent from FIG. 7B, the contact portion 50 of the source electrode 47.
Since it is necessary to electrically connect the display electrode 41 and the contact portion 50 above the above, the insulating film 45 for forming the applied voltage adjusting film is formed so as not to reach above the contact hole. There is.

7A and 7B show only an example of the structure when applied to an active matrix type liquid crystal display device, and in the present invention, a concrete structure around the applied voltage adjusting film is shown. It should be pointed out that such a structure can be appropriately modified depending on the intended liquid crystal display device.

In the example shown in FIG. 4, one pixel is divided into a plurality of stripe-shaped regions, and the dielectric constants are made different between the stripe-shaped regions. However, as shown in FIG. One pixel 33 may be divided into a plurality of rectangular regions arranged in a matrix, and regions having different dielectric constants may be formed by using the respective regions. That is, in FIG. 5A, in the center of the pixel 33, the region 3 having the highest dielectric constant is used.
3A to 33D are formed, regions 33E to 33L having the next highest permittivity are formed outside thereof, and regions 33M to 33P having the lowest permittivity are formed at the corners. The regions 33A to 33P can be formed by forming regions in the insulating film 14 of the first embodiment, which have different dielectric constants in three steps, in accordance with the regions 33A to 33P. Alternatively, in the second embodiment, regions 33 A to 33 having relatively high dielectric constants are formed in the insulating film 14.
It is formed according to L, and in the alignment film 25, regions 33A to
It can be obtained by forming a region having a high dielectric constant according to 33D.

Further, as shown in FIG. 5B, in one pixel 34, a region 3 having a relatively high dielectric constant is formed at the center.
4A may be formed to increase the dielectric constant of the central portion as compared with the remaining region 34B. Such a configuration has one pixel 34
In the first embodiment, the insulating film 14 has a region 3
It can be formed by forming regions having different dielectric constants according to 4A.

In the examples shown in FIGS. 4 and 5, the regions having different permittivities within one pixel are configured to have various planar shapes as described above, and thereby gradation display can be performed. It is said that However, in the present invention, when viewed as the entire panel of the liquid crystal display device, regions having different dielectric constants may be provided. Such an example is shown in FIG.
Is shown in the front view.

In the liquid crystal display panel 35 shown in FIG. 6, a region 35A having a relatively high permittivity is formed in the center of the display panel, and a permittivity difference is given to the surrounding region 35B. .

The present invention is characterized in that an applied voltage adjusting film is provided between the conductive film functioning as an electrode in the above liquid crystal display device and the liquid crystal to adjust the voltage applied to the liquid crystal. And thus, for example,
It can be applied to general liquid crystal display devices such as a matrix type liquid crystal display device, a TN type liquid crystal display device, a liquid crystal display device using a ferroelectric liquid crystal or an antiferroelectric liquid crystal.

[0064]

In the liquid crystal display device of the present invention, since the applied voltage adjusting film having the regions having different dielectric constants is formed on the conductive film, when a voltage is applied from the conductive film to the liquid crystal, the liquid crystal is actually applied to the liquid crystal. The voltage applied will vary from region to region. Therefore, since the movement amount of the liquid crystal molecules is different depending on the region, it is possible to widen the viewing angle, and it is possible to perform gradation display by forming the region having different dielectric constants in one pixel, for example. Become.

The applied voltage adjusting film is an alignment film,
It may be configured by a laminated film including at least one layer of insulating film, and the regions having different dielectric constants of the alignment film and the insulating film may be partially overlapped to form different regions in the applied voltage adjusting film in multiple stages. In that case, the viewing angle can be further expanded and finer gradation display can be performed.

The regions having different dielectric constants can be formed on the applied voltage adjusting film by an appropriate method such as laser irradiation, ion implantation or thermal annealing by energy beam irradiation.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a conventional liquid crystal display device.

FIG. 2 is a schematic cross-sectional view for explaining the liquid crystal display device of the first embodiment.

FIG. 3 is a schematic cross-sectional view for explaining a main part of the liquid crystal display device of the second embodiment.

4A and 4B are plan views showing an example in which stripe-shaped regions having different dielectric constants are formed in one pixel.

5A and 5B are plan views showing examples in which rectangular regions having different dielectric constants are formed in one pixel.

FIG. 6 is a plan view showing an example in which a region having a different dielectric constant is formed in the center of one liquid crystal display panel.

7A and 7B are a plan view and a cross-sectional view, respectively, for explaining a main part of an active matrix type liquid crystal display device in which an applied voltage adjusting film having the pattern of FIG. 4B is formed. .

FIG. 8 is a diagram showing the relationship between the viewing angle and the contrast ratio of the liquid crystal display devices of the present invention example and the conventional example.

[Explanation of symbols]

 11 ... Liquid crystal display device 12 ... Substrate 13 ... Conductive film 14 ... Insulating film 14a, 14b ... Regions with different dielectric constants in the insulating film 15 ... Alignment film 16 ... Applied voltage adjusting film 17 ... Liquid crystal 21 ... Liquid crystal display device 25 ... Alignment Films 25a to 25c ... Areas in which the dielectric constant is different from the remaining area

Claims (8)

[Claims] 1. A liquid crystal display device having a liquid crystal and a conductive film for applying a voltage to the liquid crystal, having an applied voltage adjusting film formed on the conductive film and having regions having different dielectric constants. And a liquid crystal display device. 2. The applied voltage adjustment film is a laminated film of an alignment film and at least one insulating film arranged between the alignment film and the conductive film, and at least one of the alignment film and the insulating film is formed. The liquid crystal display device according to claim 1, wherein one of the liquid crystal display devices has a region having a different dielectric constant. 3. The applied voltage adjusting film includes an alignment film and at least one insulating film, both the alignment film and the insulating film have regions having different dielectric constants, and the alignment film and the insulating film. 3. The regions having different dielectric constants are partially overlapped with each other, whereby a plurality of regions are formed in the applied voltage adjusting film so that the dielectric constants are different in multiple stages. Liquid crystal display device. 4. The liquid crystal display device according to claim 1, wherein the applied voltage adjustment film is an alignment film. 5. A method of manufacturing a liquid crystal display device having a conductive film for applying a voltage to liquid crystal, comprising forming an applied voltage adjusting film having regions having different permittivities on the conductive film after forming the conductive film. A method of manufacturing a liquid crystal display device, which comprises: 6. The applied voltage adjusting film has an alignment film and at least one insulating film disposed between the alignment film and the conductive film, and the dielectric film is formed by irradiating the insulating film with a laser. The method for manufacturing a liquid crystal display device according to claim 5, wherein regions having different rates are formed. 7. The applied voltage adjusting film has an alignment film and at least one insulating film arranged between the alignment film and the conductive film, and a mask is overlapped on the insulating film to perform ion implantation. The method for manufacturing a liquid crystal display device according to claim 5, wherein the regions having different dielectric constants are formed by the above. 8. The applied voltage adjusting film has an alignment film and at least one insulating film disposed between the alignment film and the conductive film, and the insulating film is partially irradiated by irradiating an energy beam. The method for manufacturing a liquid crystal display device according to claim 5, wherein the regions having different dielectric constants are formed by annealing the liquid crystal display device.