JP3356561B2 - Liquid crystal display - Google Patents

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.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices having great advantages such as thin and light weight and low power consumption have been used in personal OA devices such as Japanese word processors and desktop personal computers, and pocket televisions and wall-mounted televisions. It is actively used as a display device.

Most of such conventional liquid crystal display devices generally use a twisted nematic (TN) type liquid crystal which performs display by utilizing an optical rotation effect due to a twist of liquid crystal molecules between upper and lower substrates (cell gap). Used. The display methods can be broadly classified into two types: birefringence mode and optical rotation mode.

A liquid crystal display device of a birefringence mode display method using a twisted nematic liquid crystal has, for example, a steep electro-optical characteristic due to a molecular arrangement twisted by 90 ° or more (called an STN type). In addition, a large-capacity display can be easily obtained by a time division driving method without using a switching element using a thin film transistor or a diode for each pixel such as an active matrix type liquid crystal display device.

On the other hand, the above TN type liquid crystal display device has a 90 ° angle.
It has a so-called optical rotation mode liquid crystal layer with a twisted molecular arrangement, has a fast response speed of several tens of milliseconds, and has a high contrast ratio. Therefore, it has been frequently used in watches and calculators. Further, such a liquid crystal display device as has the performance of realizing a large-capacity and high-contrast display by providing a switching element for each pixel, such as the active matrix type liquid crystal display device described above, has been used.

[0006] Such a liquid crystal display device is also used as a liquid crystal display device capable of gradation display. There is a problem that a phenomenon observed as a so-called display defect occurs.

As means for solving these problems, 2
A liquid crystal display device in which a liquid crystal composition material is sandwiched between two substrates, and an alignment process for controlling the direction of liquid crystal molecule alignment on the substrate surface is not performed. ) And a liquid crystal display device obtained by performing the liquid crystal injecting step in a liquid state of the liquid crystal composition so that the twist angle of the liquid crystal becomes equal. Proposed by Toko et al. (“Amorphous twisted nematic-liquid
-crystal displays fabricated by nonr ubbingshowin
g wide and uniform viewing-angle characteristics a
ccompanying excellent voltage holding ratios. "Y.
Toko et al., J. Appl. Phys., Vol. 74, No. 3, pp. 2071 (199
3).).

In this liquid crystal display device, similarly to the conventional TN type liquid crystal display device, for example, an alignment film made of a material having wettability for controlling the pretilt attitude of liquid crystal molecules in the elevation direction with respect to liquid crystal molecules, such as a polyimide material, is provided. After application to the substrate, the upper and lower substrates are joined with a sealing material disposed around the upper and lower substrates without forming an alignment treatment such as rubbing on the surface to form an empty cell, and the liquid crystal composition is applied to the empty cell. Is heated to a temperature equal to or higher than the melting point and filled in a liquid state. The liquid crystal display device thus obtained has a structure in which the liquid crystal molecules are substantially horizontal to the substrate and have a twist between the upper and lower (or left and right) substrates (for example, a 90 ° twist in the TN type) when no voltage is applied. Nevertheless, since the alignment treatment such as rubbing in the horizontal (parallel) plane direction with respect to the main surface of the substrate is not performed on the alignment film, the director orientation of the liquid crystal molecules on the alignment film surface is not determined.

As a result, the optical rotation effect of the liquid crystal layer has various orientations in the horizontal (parallel) in-plane direction (azimuth) with respect to the main surface of the substrate.

When such a liquid crystal cell is inserted between orthogonal polarizing plates and observed, the optical rotation effect of the liquid crystal layer having various orientations is averaged and observed. It is possible to observe transmitted light of brightness and color that averages the normally-light-driven type and the extraordinary-light-driven type in the normally white mode.

When a voltage is applied to the liquid crystal display device,
The liquid crystal molecules tilt in the normal direction of the substrate as in the conventional TN mode, but the tilt direction is variously random because the director direction of the liquid crystal molecules on the surface of the wiring film is not determined. Therefore, a large number of disclination lines are generated corresponding to the applied voltage, and the halftone display is performed by the light scattering effect of the disclination lines and the non-rotational effect of the light other than the disclination line generating portion. Can be realized. When a sufficient voltage is applied to the liquid crystal layer, the liquid crystal layer is controlled such that liquid crystal molecules having no disclination line are tilted substantially in the normal direction of the substrate as in the conventional TN type liquid crystal display device. The resulting display is almost black.

Here, the director orientation of the liquid crystal molecules is determined by the direction of the screen in any of the no-voltage application state, the voltage application state for obtaining a halftone, and the sufficient voltage application state in which the liquid crystal molecules are tilted substantially in the normal direction of the substrate. Various directions for each position,
Since the azimuth is taken, this liquid crystal display device has the same display appearance from any direction. That is,
This is a liquid crystal display device in which the display performance does not depend on the observation direction.

Further, in this liquid crystal display device, when the tilt of the liquid crystal molecules increases, that is, when the applied voltage is increased, the tilt direction is in various directions. By obtaining an action equivalent to a change in the inclination without azimuth, the change in retardation of the liquid crystal layer is reduced even in moderate directions. Further, since the light scattering effect of the large number of disclination lines is used as a means for obtaining the intermediate gradation display, there is an advantage that the so-called display inversion phenomenon does not occur even when the gradation display is performed.

As described above, in this liquid crystal display device, when a certain wide display area is considered as one unit, the individual display characteristics of an extremely fine area are averaged and observed. A liquid crystal display device having excellent display performance with extremely little viewing angle dependence is provided.

However, due to the characteristic that the disclination line repeatedly occurs and disappears due to the fluctuation of the applied voltage, there is a hysteresis in the voltage-transmittance of the liquid crystal display device. At the same time, there was a problem that the response speed was reduced.

[0016]

As described above, the conventional TN type liquid crystal display device has a problem of viewing angle dependence such as a decrease in contrast and a display reversal phenomenon at the time of gradation display. Y. The liquid crystal display device proposed by Toko et al. Has a problem that an afterimage occurs and a problem that the response speed is lower than that of the conventional TN type liquid crystal display device.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a liquid crystal display device according to the prior art as described above in which the contrast is reduced or the display at the time of gradation display is performed. To provide a liquid crystal display device that achieves high contrast, wide viewing angle characteristics, high-speed response, and large-capacity display performance by eliminating the problem of viewing angle dependence such as inversion phenomenon, and the problems of generation of afterimages and reduction of response speed. It is in.

[0018]

According to the present invention, there is provided a liquid crystal display device comprising: a first substrate; a second substrate opposed to the first substrate with a gap therebetween; A sealing material disposed around the substrate and the second substrate to join the first substrate and the second substrate, and the first substrate surrounded by the sealing material. The liquid crystal molecules are sealed and sandwiched in the gap with the second substrate, and the liquid crystal molecules are applied between the two substrates without voltage application.
In the state, a plane that is almost parallel to each of the substrates and parallel to the substrates
The voltage is applied randomly between the two substrates.
The disclinator only within the specified voltage range.
In the liquid crystal display device having a nematic type liquid crystal layer of the in-occurs, disclination lines always
A liquid crystal driver that drives the liquid crystal layer with a drive voltage in a range in which the liquid crystal is generated.
A liquid crystal layer, wherein the liquid crystal layer has a twisting capability of the liquid crystal molecules.
By force, the gap between the first substrate and the second substrate
The twist angle of the alignment of the liquid crystal molecules is determined .

A first substrate; a second substrate opposed to the first substrate with a gap therebetween;
Sealing material disposed around the first and second substrates and joining the first substrate and the second substrate, and the first substrate surrounded by the sealing material Liquid crystal molecules are enclosed and sandwiched in a gap between the first substrate and the second substrate, and liquid crystal molecules are interposed between the two substrates.
When no voltage is applied to the substrate,
The two substrates are randomly arranged in a plane parallel to the plate.
When a voltage is applied between the discs and only within the specified voltage range
In a liquid crystal display device having a nematic liquid crystal layer in which a ligation line is generated, a horizontal surface formed on at least one of the first substrate and the second substrate with respect to a main surface of the substrate the azimuth angle of the liquid crystal molecules of the liquid crystal layer on the inner alignment film for controlling the pretilt angle of the elevation direction of the liquid crystal molecules of the liquid crystal layer with respect to the main surface of the substrate without restriction, de I subscription destination line always < a liquid crystal driving circuit for driving the liquid crystal layer at a driving voltage in a range in which the liquid crystal molecules are generated.
Gap between the first substrate and the second substrate depending on the capacity
Wherein the twist angle of the arrangement of the liquid crystal molecules is determined .

[0020]

In the gap between a pair of electrodes opposed to each other with a gap, liquid crystal molecules are charged between the electrodes.
When no pressure is applied, it is almost parallel to each electrode and
Randomly arranged in parallel planes, between the two electrodes
When a voltage is applied, the disc
A liquid crystal layer using the nematic liquid crystal molecules whose twist angle is determined by the twisting ability of the liquid crystal molecules is held in a state where the liquid crystal molecules are arranged in a direction in which the alignment direction of the liquid crystal molecules is not determined, and a light modulation region by the liquid crystal layer is held. In the liquid crystal display device in which is formed, a potential difference within a range in which a disclination line is always maintained without disappearing in the light modulation region is applied between the pair of electrodes to drive the light modulation region and display. And a liquid crystal drive circuit for performing the following. A first substrate including a pixel electrode arranged in a matrix and a switching element arranged for each of the pixel electrodes and controlling voltage application to the pixel electrode; and a gap with respect to the first substrate. A second substrate having the first substrate and the second substrate
A sealing material disposed around the first substrate and joining the first substrate and the second substrate, and the first substrate and the second substrate surrounded by the sealing material The liquid crystal molecules are enclosed and sandwiched in the gap between the two substrates, and no voltage is applied between the two substrates.
Is in a plane substantially parallel to each of the substrates and parallel to the substrates.
Arranged randomly and applying a voltage between the two substrates
Only when the disclination line is within the specified voltage range.
The generated nematic liquid crystal layer and liquid crystal molecules of the liquid crystal layer formed on at least one of the first substrate and the second substrate in a horizontal plane with respect to a main surface of the substrate. azimuth and alignment film for controlling the pretilt angle of the elevation direction of the liquid crystal molecules of the liquid crystal layer with respect to the main surface of the substrate without restriction, before Symbol liquid crystal layer is always disclination line occurs on the pixel electrode Range of drive power
And a liquid crystal drive circuit that controls the liquid crystal layer with pressure . Further, the liquid crystal layer has a positive dielectric anisotropy and has a twisting ability.

[0022]

The operation of the above Y. When a voltage is applied to the liquid crystal display device proposed by Toko et al.
Tilt in the normal direction of the substrate as in the case of the liquid crystal display device,
The tilt direction is variously random because the director direction of liquid crystal molecules on the surface of the alignment film is not determined.

The present inventors have confirmed by various experiments the behavior of generation and disappearance of disclination lines in such a randomly oriented liquid crystal layer. After the start of voltage application,
At a moderate applied voltage, a large number of disclination lines are generated, and at a sufficient applied voltage, the disclination lines disappear. That is, when the liquid crystal display device is actually driven, the generation and disappearance of the disclination line are repeated in response to the fluctuation of the applied voltage, and hysteresis occurs in the voltage-transmittance of the liquid crystal display device as shown in FIG. become. For this reason, an afterimage occurs and the response speed decreases.

Therefore, in the liquid crystal display device of the present invention, no alignment treatment for controlling the alignment direction of the liquid crystal molecules on the substrate surface is performed, and the twisting ability (chiral ability) of the liquid crystal composition and the twisting of the liquid crystal. The liquid crystal layer is operated in the liquid crystal display device having the same angle while the disclination line is always generated.

For this purpose, for example, the liquid crystal layer is driven with a liquid crystal applied voltage within a range where the disclination line does not disappear. For this purpose, for example, a liquid crystal driving circuit that outputs the above-described liquid crystal application voltage may be used.

As described above, by avoiding the transition from the occurrence of the disclination line to the disappearance and the disappearance to the occurrence, the hysteresis of the voltage-transmittance does not appear in the operation characteristics of the liquid crystal layer as shown in FIG. Can be Here, since the disclination line itself is hardly noticeable in the display screen, there is practically no deterioration in display quality due to the existence of the disclination line itself. Although it is theoretically possible that the contrast is reduced only by this disclination line,
There is almost no problem in practical use of the display. Rather, the above-mentioned effect of eliminating the hysteresis of the liquid crystal layer by maintaining the state in which the disclination line exists contributes greatly to the improvement of display quality. As a result, a liquid crystal display device having high contrast, good viewing angle characteristics, no display defects such as afterimages, high-speed response, and large-capacity display performance is realized by using a liquid crystal layer of random alignment. Can be.

The technology of the present invention can be applied in combination with technologies such as a TFT system, a TFD (Thin-Film-Diode) system, a simple matrix system, a segment system (static drive), and a GH mode in a liquid crystal display device. Needless to say,

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the liquid crystal display device of the present invention will be described in detail following the manufacturing process.

(Embodiment 1) As shown in FIG. 1A, a liquid crystal display panel 100 used in the liquid crystal display device of the present invention.
In, a pixel electrode 101 and a switching element TF as a switching element for controlling voltage application to the pixel electrode 101
A TFD substrate 104 provided with a D (Thin-Film-Diode) element 102 on a main surface of a transparent substrate 103 such as a glass substrate
On the opposite substrate 107 provided with the opposite electrode 106 made of ITO, which is formed by printing on the main surface of a transparent substrate 105 such as a glass substrate, such as a glass substrate, a slight amount of about 2 ° is applied without performing an alignment process. AL-3046 is an alignment film material that provides horizontal alignment ability to regulate the orientation of liquid crystal molecules at tilt angles.
(Manufactured by Nippon Synthetic Rubber Co., Ltd.) at 150 ° C for 1 hour,
Thereafter, without performing any alignment treatment such as a rubbing alignment treatment, alignment films 108 and 109 were formed on the TFD substrate 104 and the counter substrate 107, respectively.

Next, the substrate gap material 111 has a particle size of 5.0 μm.
m micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.)
Is applied on the main surface of the substrate including the counter electrode 106 on the side of the counter substrate 107 on which the counter electrode 106 is formed, and sealed around the display area, that is, the periphery surrounding the screen area of the transparent substrates 103 and 105. The dressing material 112 is arranged, and the TF
Both substrates of the D substrate 104 and the opposing substrate 107 are arranged facing each other with a gap between them so that the alignment films 108 and 109 face each other. A heat treatment was performed while applying pressure so as to be substantially equal to the particle size of the gap material 111, and the sealing material 112 was cured, thereby producing a liquid crystal display panel in an empty cell state of the liquid crystal display device of the present invention.

Next, the liquid crystal composition which is a material for forming the liquid crystal display panel and the liquid crystal layer in the empty cell state is inserted into a vacuum chamber equipped with a heating device, and the above empty cell is heated to a temperature not lower than the melting point of the liquid crystal composition. The liquid crystal display panel and the liquid crystal composition are heated, and the liquid crystal composition is immersed in the inlet of the cell under reduced pressure. After filling in the cell, the cell was cooled to obtain a liquid crystal layer 113.

The liquid crystal layer 113 is a so-called random alignment liquid crystal layer having a random azimuth angle. Thus, the main part of the liquid crystal display device of the present invention is manufactured.

Here, as the liquid crystal composition, ZLI which is a nematic liquid crystal material having a positive dielectric anisotropy is used.
At −4792 (Δn = 0.094, melting point = 92 ° C., manufactured by Merck Japan Co., Ltd.), the twist angle of liquid crystal molecules is 90 μm in a cell gap of 5.0 μm (that is, a substrate gap having a distance substantially equal to the thickness of the liquid crystal layer). ° as s-81 as a chiral agent
1 (manufactured by Merck Japan Co., Ltd.) mixed at 0.41 wt% was used. In the above-described liquid crystal composition filling step (liquid crystal injection step), the substrates 104 and 107 and the liquid crystal composition are heated to 100 ° C.
Heating was performed. The liquid crystal display device in this embodiment has a diagonal of 4 inches, a pixel pitch of 180 μm, 320 × 480 dots, a driving method of a PWM gradation display method, and a minimum number of permanent disclinations of 5 to 10 lines. It was made with the specifications of the screen.

The liquid crystal display panel thus formed is inserted between the orthogonal polarizers 201 and 202 as shown in FIG. 1, a backlight 203 is arranged on the back side of the TFD substrate 104, and the liquid crystal display panel 100 A liquid crystal driving circuit (not shown) such as a liquid crystal driver IC is connected, and is driven by an applied voltage in a region where a disclination line always occurs and no hysteresis appears in the voltage-transmittance characteristic as shown in FIG. did.

As a result, it could be confirmed that the contrast was high, there was no coloring, there was no afterimage, and the response speed was high.

Further, when the liquid crystal display device of the present embodiment obtained in this manner was driven by performing gradation display in an area where a disclination line was always generated and observed from various directions, It has a good contrast ratio when viewed from the direction, no reversal phenomena, no roughness of the displayed image, and a very good viewing angle characteristic that hardly perceives the viewing angle dependency. It has been confirmed that the liquid crystal display device has practically excellent characteristics as a direct-view type liquid crystal display device that is expected to observe a screen.

(Embodiment 2) As shown in FIG. 2, the liquid crystal display device of the first embodiment is
2 was inserted between a polarizing plate 303 attached to the back surface (the polarizing axes (absorption axes) of the polarizing plates are orthogonal) 303 to obtain a liquid crystal display device having a reflective structure. As another structure, as in the first embodiment, a disclination line is always generated in the voltage-transmittance characteristic curve shown in FIG. 3 by using a switching element made of TFD or the like, and the voltage-transmittance has a hysteresis. Is driven in a region having no. As a result, as in the first embodiment, the viewing angle characteristic is excellent in any direction as viewed from any direction, there is no reversal phenomenon, there is no roughness of the displayed image, and the viewing angle dependence is hardly felt. It has been confirmed that the liquid crystal display device has excellent display performance and has practically excellent characteristics as a direct-view type liquid crystal display device which is expected to observe a screen from various angles.

In each of the above embodiments, a TN type liquid crystal is used as the liquid crystal composition used for the liquid crystal layer. However, it goes without saying that the present invention is not limited to this. In addition to this, for example, ST having a twist angle of 90 ° or more
N-type liquid crystal, GH (guest-host) type liquid crystal in which coloring molecules such as dyes are mixed in a liquid crystal phase, and a liquid crystal display device of a type that performs display by controlling the twist of liquid crystal molecules in a liquid crystal layer between cell gaps. Needless to say, this is also suitable.

In the above embodiment, the case where an active matrix type liquid crystal display device having a TFD is used as the liquid crystal display panel has been described. However, the application of the present invention is not limited to this. Needless to say, the present invention can be applied to, for example, a liquid crystal display panel using a TFT as a switching element or a liquid crystal display device using a simple matrix type liquid crystal display panel.

[0040]

As described in the detailed description above, according to the present invention, there is a problem of viewing angle dependence such as a decrease in contrast and a display inversion phenomenon at the time of gradation display, generation of an afterimage and a response speed. It is possible to provide a liquid crystal display device which has solved the problem of deterioration and realized high contrast, wide viewing angle characteristics, high-speed response, and large-capacity display performance.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic structure of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic structure for showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a voltage-transmittance characteristic of the liquid crystal display device of the present invention.

FIG. 4 is a diagram showing a voltage-transmittance characteristic of a conventional liquid crystal display device accompanied by occurrence and disappearance of a disclination line.

[Explanation of symbols]

 100: liquid crystal display panel 101: pixel electrode 102: TFD element 103: transparent substrate 104: TFD substrate 105: transparent substrate 106: counter electrode 107: counter substrate 108 , 109: alignment film 111: substrate gap material 112: sealing material 113: liquid crystal layer 201, 202: orthogonal polarizing plate 203: backlight

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazushi Miyake 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Corporation Yokohama Office (72) Inventor Junko Hirata 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Inside Yokohama Office (72) Inventor Masahito Ishikawa 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Corporation (72) Inventor Shinichi Kamakami 8 Shin-Sugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Yokohama Business Toshiba In-house (72) Inventor Hitoshi Hato 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Yokohama office of Toshiba Corporation (72) Inventor Hiroshi Morita 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa prefecture Inside the Yokohama office of Toshiba Corporation (56) References JP-A-6-258649 (JP, A) JP-A-8-43833 (JP, A) JP-A-7 JP-A-7-181492 (JP, A) JP-A-7-181490 (JP, A) JP-A-7-159787 (JP, A) JP-A-7-151627 (JP, A) JP-A-7-128669 (JP, A) JP-A-7-120728 (JP, A) JP-A-7-84260 (JP, A) JP-A-7-49499 (JP, A) 308543 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1337 G02F 1/137 G02F 1/1343

Claims (5)

(57) [Claims] 1. A first substrate, and a second substrate opposed to the first substrate with a gap therebetween.
A sealing material disposed around the first substrate and the second substrate and joining the first substrate and the second substrate, and surrounding the circumference with the sealing material The first substrate and the second substrate
Liquid crystal molecules are enclosed and sandwiched in the gap with the substrate of
In the state where no voltage is applied between the plates, it is almost parallel to
In a plane parallel to the substrate, they are randomly arranged,
When a voltage is applied between the substrates, the
In a liquid crystal display device having a nematic liquid crystal layer in which a screen line is generated, a drive in a range in which a disclination line always occurs.
A liquid crystal driving circuit that drives the liquid crystal layer with a voltage, wherein the liquid crystal layer has a twist angle of an arrangement of the liquid crystal molecules in a gap between the first substrate and the second substrate due to a twisting capability of the liquid crystal molecules. the liquid crystal display device, wherein a determined. 2. A first substrate, and a second substrate opposed to the first substrate with a gap therebetween.
A sealing material disposed around the first substrate and the second substrate and joining the first substrate and the second substrate, and surrounding the circumference with the sealing material The first substrate and the second substrate
Liquid crystal molecules are enclosed and sandwiched in the gap with the substrate of
In the state where no voltage is applied between the plates, it is almost parallel to
In a plane parallel to the substrate, they are randomly arranged,
When a voltage is applied between the substrates, the
A liquid crystal display device having a nematic liquid crystal layer in which a screen line is generated , comprising: a main substrate formed on at least one of the first substrate and the second substrate; and an alignment film for controlling the pretilt angle of the elevation direction of the liquid crystal molecules of the liquid crystal layer azimuth angle of the liquid crystal molecules of the liquid crystal layer with respect to the main surface of the substrate without restriction in the horizontal plane relative to the surface, disclinations Drive within the range where lines always occur
Comprising a liquid crystal driving circuit which drive the liquid crystal layer with a voltage, the liquid crystal layer, the arrangement of the liquid crystal molecules in the gap between the first substrate and the second substrate by the torsion capacity of the liquid crystal molecules the liquid crystal display device characterized by twist angle is determined. 3. A gap between a pair of electrodes disposed opposite to each other with a gap is filled with liquid crystal molecules without a voltage between the electrodes.
In the state of application, it is almost parallel to each electrode and parallel to the electrode
Are randomly arranged in a plane where
When disk drive is applied, disclination is performed only within the specified voltage range.
A liquid crystal layer using the nematic liquid crystal molecules whose twist angle is determined by the twisting ability of the liquid crystal molecules is held in a state where the alignment direction is generated and the alignment direction of the liquid crystal molecules is not determined, and a light modulation region by the liquid crystal layer is held. In the liquid crystal display device, a potential difference within a range in which the disclination line is always kept without disappearing in the light modulation region is applied between the pair of electrodes, and the light modulation region is driven to display. A liquid crystal display device comprising a liquid crystal drive circuit for performing the following. 4. A first substrate comprising: a pixel electrode arranged in a matrix; and a switching element arranged for each of the pixel electrodes, the switching element controlling voltage application to the pixel electrode. And a second opposing arrangement with a gap
A sealing material disposed around the first substrate and the second substrate and joining the first substrate and the second substrate, and surrounding the circumference with the sealing material The first substrate and the second substrate
Liquid crystal molecules are enclosed and sandwiched in the gap with the substrate of
In the state where no voltage is applied between the plates, it is almost parallel to
In a plane parallel to the substrate, they are randomly arranged,
When a voltage is applied between the substrates, the
A nematic liquid crystal layer in which a screen line is generated ; and a horizontal plane formed on at least one of the first substrate and the second substrate with respect to a main surface of the substrate. An alignment film that controls the pretilt angle of the liquid crystal molecules of the liquid crystal layer in the elevation direction with respect to the main surface of the substrate without restricting the azimuth angle of the liquid crystal molecules of the liquid crystal layer, and the liquid crystal layer is formed on the pixel electrode. A liquid crystal display device comprising: a liquid crystal drive circuit that controls the liquid crystal layer with a drive voltage in a range where a disclination line always occurs. 5. The liquid crystal display device according to claim 4 , wherein the liquid crystal layer has a positive dielectric anisotropy and has a twisting ability.