JPH0968697A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the seam of liquid crystal panels hardly viewed even when the plural liquid crystal panels are joined by setting the polarizing axis of one polarizing plate in an identical direction to the seam when the liquid crystal panels are joined. SOLUTION: A liquid crystal display element 1 is constituted by joining the joining surfaces 3 of two liquid crystal panels 2. Then, the polarizing plates 4 and 5 are provided on both sides of the element 1 in the thickness direction by interposing the element 1. Both plates 11 and 5 are provided in a polarizing axis direction that they are mutually orthogonally crossed. Besides, the polarizing axis of one polarizing plate is almost aligned with the joining surface 3. When the element 1 and the plates 4 and 5 are constituted in such a way, light transmitted through the plate 4 is emitted in a direction along the polarizing axis of the plate 4 and made incident so that the plane of the polarization thereof is faced in a vertical direction with respect to the joining surface 3. Therefore, the plane of the polarization is not rotated and it becomes black under a cross Nicol prism.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, a large CR.
It can be used as a substitute for T, or can be used for AV related displays such as multimedia, displays for design personal computers such as CAD, and display devices used by a large number of people for presentations, etc. A large size that connects multiple liquid crystal panels Liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, home televisions used as AV equipments and display devices used in OA equipments have been made lighter and thinner, and have lower power consumption, higher definition and larger screens. The demand is increasing. This request is a CRT
(Cathode-Ray Tube) display,
LCD (Liquid Crystal Display)
y), plasma display, EL (Electro
Luminescent display, LED (L
It is also used in a display device such as a light emitting diode display, and development has been performed to meet the demand, and a part thereof is being put into practical use.

By the way, at home, the position of televisions for entertainment purposes is increasing. Even considering the actual sales situation of TVs, although the price per inch has dropped, it is gradually shifting to larger TVs, and with the stereoization of audio, further enlargement of the screen for home TV It is an essential requirement. Similarly, in the business field, it is easy to handle, clear images can be obtained not only for still images but also for moving images, and it can be applied to presentations using computers, etc. Also from the viewpoint that it can be used, the display device as described above has been used, and further enlargement is expected.

Among the above-mentioned display devices, the liquid crystal display device has a merit that it is light in weight and can be easily installed in a narrow space because the dimension in the depth direction, that is, the thickness can be markedly thinner than other display devices. There is also
In recent years, it has been used in various fields because of its low power consumption and easy full-color display, and expectations for a larger screen than other display devices are increasing.

By the way, when increasing the size of the display screen,
If the resolution per screen is the same, the rough image is very conspicuous. Therefore, it is necessary to improve the image resolution as well as the image quality of the video source. In a liquid crystal display device, an image is formed by a number of independently controllable pixels that are integrally formed at the same time, and improving the resolution is nothing but increasing the number of the pixels.

However, the reduction of the defect rate of each pixel alone in the manufacturing process is almost at the present stage, and no dramatic progress can be expected. Therefore, increasing the number of pixels with the increase in screen size of the liquid crystal display device deteriorates the manufacturing yield of the entire display device at an accelerating rate. As a result, a liquid crystal display device with a large screen and high image quality cannot be obtained. ,
It becomes difficult to increase the production amount and it becomes very expensive.

Therefore, in order to solve the above-mentioned problem, a method is adopted in which a plurality of liquid crystal panels are connected to each other to display one image, and a so-called multi-panel display type liquid crystal display device is used to increase the size of the screen. Has been done. By using such a method, even if the defect rates of the liquid crystal panels are the same, the defect rate of the liquid crystal display device as a whole can be dispersed, and the yield of the liquid crystal display device as a whole can be improved. Therefore, it is possible to suppress an increase in cost per unit area and obtain a liquid crystal display device having a large screen and high image quality at low cost.

As a technique for adhering the substrates, which is used when manufacturing the above-mentioned liquid crystal display device of the multi-panel display system, a plurality of LCD substrates are joined with a polymer material, and the protruding portion is etched using laser light. However, a technique for flattening the substrate has been proposed (Japanese Patent Laid-Open No. Hei 1
-213621). In this proposed technique, the TN mode is used, and as shown in FIG.
The polarization axes of 4 and 25 (indicated by arrows) are set in the directions rotated by 45 ° with respect to each side of the liquid crystal panel 22, particularly the joint surface 23.

As a technique for concealing a joint which is a joint surface of a liquid crystal panel, a technique has been proposed in which a plurality of liquid crystal panels are attached to one reinforcing substrate and a light shielding layer for concealing the joint is provided on the reinforcing plate. We are (actual fair 6-17178
issue). Furthermore, the applicant of the present application has proposed a method of concealing a joint by adding a material that absorbs light into a bonding material when bonding a plurality of LCD substrates with a polymer material (Japanese Patent Application No. 6- 210216).

[0010]

However, in the former case, when the liquid crystal panel is tilted and observed, the adjacent picture elements are hidden by the light-shielding layer, and the seams are rather conspicuous. In the latter case, the concealment effect is very good, but the TN mode is used,
Since the polarization axis of the polarizing plate is set to 45 ° with respect to each side of the liquid crystal panel, there is a weak point that light leakage at the seams partially occurs due to subtle differences in refractive index and distortion during processing. is there.

Since there is an interface where the substrates are bonded to each other, the visibility of the bonded surface is greatly affected by the positional relationship between the polarization axis of the polarizing plate and the bonded surface under the crossed Nicols. That is, as shown in FIG. 13, since the S-wave and the P-wave have different reflectances on the joint surface, if the joint surface and the polarization axis of the polarizing plate are deviated from each other, a direction other than a direction parallel or perpendicular to the joint surface is obtained. In the case of incident light having a plane of polarization, the plane of polarization of the reflected light deviates from the plane of polarization of the incident light and slightly rotates, and as a result, the light leaks from the analyzer in the direction of 90 °. This light leakage phenomenon is similar to the phenomenon that occurs when S waves and P waves are reflected at the interface between air and glass, that is, the phenomenon shown in FIG. This light leakage phenomenon is greatest when the joint surface is arranged at 45 ° from the polarization axis of the polarizing plate.

The adhesive present on the joint surface generally produces a minute birefringence component due to shrinkage during polymerization or compression during joining, and the main axis of the birefringence component is horizontal or vertical to the joint surface. Oriented in the direction. In this state, when polarized light having a plane of polarization other than parallel or horizontal to the joint surface passes through the joint surface, it becomes elliptically polarized light at the joint surface.
It causes light leakage. Also in this case, light leakage is greatest when the joint surface is arranged in the direction of 45 ° from the polarization axis of the polarizing plate.

The present invention has been made to solve the above-mentioned problems of the prior art, and provides a liquid crystal display device of a multi-panel display system which makes it difficult to see the joints even when a plurality of liquid crystal panels are connected to each other. The purpose is to do.

[0014]

A liquid crystal display device according to the present invention comprises a liquid crystal display element having a display section in which a plurality of liquid crystal panels are joined and arranged in parallel, and the liquid crystal display element is sandwiched in the thickness direction thereof. At least one of the polarizing plates provided on both sides is installed so that its polarization axis substantially coincides with the direction along the joint between the plurality of liquid crystal panels forming the liquid crystal display element. The above object is achieved by the above.

In the liquid crystal display device according to the present invention, the liquid crystal panel has a plurality of liquid crystal regions separated by polymer walls, and each liquid crystal region is arranged so that the liquid crystal molecules are aligned in two or more directions. be able to.

In the liquid crystal display device of the present invention, an alignment means for aligning liquid crystal molecules in two or more directions is provided on at least one of the two substrates provided in the liquid crystal panel. be able to.

In the liquid crystal display device of the present invention, in the liquid crystal panel, an alignment layer is formed on at least one of the two substrates provided in the liquid crystal panel in contact with the liquid crystal region, and the alignment layer is crystalline. It can be formed of a polymer and have a spherulite structure.

In the liquid crystal display device of the present invention, in the liquid crystal panel, the alignment layer provided on at least one of the two substrates provided in the liquid crystal panel is in a non-aligned state, and the liquid crystal region is randomly aligned. It can be a different configuration.

In the liquid crystal display device of the present invention, the liquid crystal panel may have a configuration in which the alignment state of liquid crystal molecules is axially symmetrical.

Next, the operation of the present invention will be described.

According to the present invention, in the joining of liquid crystal panels aiming at a large screen, the polarization axis of one of the polarizing plates is set in the same direction as the joint. When the liquid crystal panels are jointed in this way, the polarization plane incident on the joint surface, which is a joint, is incident on the joint surface in a direction parallel or perpendicular to the joint surface. For this reason, the plane of polarization does not rotate, and a black state is obtained under crossed Nicols.

Further, by using a liquid crystal display mode having excellent viewing angle characteristics in the polarization axis direction (4 directions), it is possible to manufacture a liquid crystal display device in which the seams are difficult to see and the viewing angle characteristics are symmetrical.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below item by item.

(Cell Structure) As shown in FIGS. 1 (a) and 2 (a), the liquid crystal display device of the present invention has a plurality of liquid crystal panels 2, and in the illustrated example, two liquid crystal panels 2 are bonded to each other on a bonding surface 3.
The liquid crystal display element 1 is formed by joining the liquid crystal display elements 1 to each other, and the polarizing plates 4 and 5 are provided on both sides in the thickness direction of the liquid crystal display element 1 with the liquid crystal display element 1 interposed therebetween. Both polarizing plates 4 and 5 are shown in FIG.
As shown in (b) and FIG. 2 (a), the polarization axes are orthogonal to each other, and the polarization axis of one of the polarizing plates and the joint surface 3 are substantially aligned.

In this way, the liquid crystal display element 1 and the polarizing plates 4, 5 are
2 is configured, the light transmitted through the polarizing plate 4 is in the direction along the polarization axis of the polarizing plate 4, and the polarization plane of the light is as shown in FIG. 2 (c). Is incident on the joint surface 3 in a direction perpendicular to the joint surface 3. For this reason, as shown in FIG. 2D, the plane of polarization does not rotate, and a black state is obtained under crossed Nicols.

Further, when the bonding surface contains a bonding agent having a minute birefringence, and the bonding surface (line) and the polarization axis of one of the polarizing plates have an angle, the bonding is performed as in the present invention. Light leakage can be prevented by making the plane (line) and the polarization axis of one of the polarizing plates substantially coincide with each other. Explaining this in detail, as shown in FIG. 3A, as in the conventional case, a liquid crystal display element 21 in which a liquid crystal panel 22 is connected is
Polarizing axes 24,
When 5 is combined, the light linearly polarized by the polarizing plate 4 becomes elliptically polarized light due to the birefringent component due to the bonding agent existing on the bonding surface 3 as shown in FIG. Light leakage occurs. On the other hand, as in the present invention, the effect of preventing light leakage is maximized by making the bonding surface (line) and the polarization axis of one of the polarizing plates substantially coincide with each other.

From the above two points of view, as shown in FIG.
It is preferable that the bonding surface (line) 3 and the polarization axis of one of the polarizing plates are substantially aligned. The light leakage phenomenon is the smallest when the bonding surface and the polarization axis of one of the polarizing plates are aligned with each other. Also in the TN mode and the STN mode, it is preferable to apply such a method of laminating the polarizing plates, because it has the effect of making the joint surface difficult to see.

In particular, in the case of the TN mode, it is preferable to use the wide viewing angle display mode. The reason is as follows. In the case of the TN mode, when the polarization axis direction of one of the polarizing plates is shifted by 45 ° with respect to the bonding surface as shown in FIG. 4 (b), it is excellent in left-right symmetry as shown in FIG. 4 (a). However, as shown in FIG. 4D, if the direction of the polarization axis of one of the polarizing plates is aligned with the joint surface, the left-right symmetry shifts as shown in FIG. 4C. In this case, if the wide viewing angle display mode described below is used, the deviation of the left-right symmetry can be suppressed because the symmetry of the viewing angle characteristics is excellent.

(Wide Viewing Angle Display Mode) In the above structure (how to attach the polarizing plate and how to join the panels), the display mode displayed in the panel becomes a problem. That is, in the conventionally used TN mode, the viewing angle dependency is large and the viewing angle characteristics having extreme anisotropy in the left and right directions when the direction of the polarization axis of the polarizing plate is set in the vertical and horizontal directions of the panel are difficult to see. It becomes a liquid crystal display device.

Therefore, in the present invention, when the polarizing axes of the polarizing plate are attached vertically and horizontally, the viewing angle characteristics are good in the polarizing axis direction,
Further, it is more preferable to use a liquid crystal display element having excellent symmetry in viewing angle characteristics.

As the wide viewing angle display mode of the liquid crystal display device, the following liquid crystal display modes in which liquid crystal molecules are aligned in two or more directions can be used.

The first mode is a mode using a non-scattering type polarizing plate. In this case, by forming a polymer protrusion in the cell by phase separation from a mixture of liquid crystal and a photo-curable resin, and disturbing the alignment of liquid crystal molecules, the viewing angle characteristics are improved (Japanese Patent Laid-Open No. HEI 5-1951). 27242). In particular,
The orientation of the liquid crystal domains becomes random due to the generated polymer, and the rising direction of the liquid crystal molecules is different in each liquid crystal domain when a voltage is applied, so the apparent refractive index (brightness) seen from each direction is They are equal, which improves the viewing angle characteristics in the halftone state.

The second mode is a mode in which liquid crystal molecules are oriented in axial symmetry. In this case, there are the following three ways. One of them is a mode in which liquid crystal molecules are oriented in axial symmetry by forming axisymmetric thin grooves for each picture element on a substrate (Japanese Patent Laid-Open No. 6-324337). The other one is a mode in which each pixel is subjected to an axially symmetrical orientation process (Japanese Patent Laid-Open No. 6-324337). In these two modes, the alignment directions of liquid crystal molecules on the upper and lower substrates are orthogonal to each other. The other one is a mode in which liquid crystal molecules are surrounded by polymer walls for each picture element and aligned in axial symmetry (Japanese Patent Laid-Open No. 61301010).

In the second mode, the liquid crystal molecules are omnidirectionally aligned (swirl) in the pixel region by controlling the light with a photomask during photopolymerization, and the liquid crystal molecules are controlled by the voltage. As a result, the spiral orientation changes to a homogeneous state, and the viewing angle characteristics are significantly improved.

The third mode is a wide viewing angle display mode in which an alignment film having a spherulite structure is formed on the substrate surface using a crystalline polymer, and the axially symmetrical alignment regulating force of the alignment film is utilized. (Japanese Patent Application Laid-Open No. 6-308496).

The fourth mode is a mode in which liquid crystal molecules are aligned in a random direction without applying alignment treatment such as rubbing, by applying an alignment film on a substrate (Japanese Patent Laid-Open No. 6-119).
4655).

The fifth mode is a mode (picture element dividing method) in which the picture element is divided into two areas and the orientation states are different from each other, thereby compensating for the areas having poor viewing angle characteristics.

In the case of such a mode, it becomes possible to orient the liquid crystal molecules in at least two directions within the picture element, and the viewing angle characteristics of the liquid crystal display device can be improved. Specifically, in such an alignment state, apparent refraction of liquid crystal molecules when viewed from both A and B directions in a halftone state as shown in (a-1) to (a-3) of FIG. The rates (brightness) are averaged so that the transmittances from both A and B directions become equal, and the viewing angle characteristics are improved compared to the TN mode shown in (b-1) to (b-3) of FIG. .

In any of these liquid crystal display devices in which such a liquid crystal display element is sandwiched between a pair of polarizing plates under the crossed Nicols condition, the liquid crystal molecules are aligned in the electric field direction when a saturation voltage is applied. And the viewing angle characteristic dependence of the black level is almost the same. Therefore, the viewing angle characteristic dependency has the same tendency although the contrast differs for each display mode.

FIG. 6 shows an outline of viewing angle characteristics of a liquid crystal display device using the liquid crystal display element of the above mode. Figure 6
(B) shows the direction of the polarization axis of the liquid crystal display device,
(A) shows the viewing angle characteristic in that case.

As can be understood from FIG. 6, the viewing angle characteristics are relatively wide in the axial direction, and the viewing angle characteristics are excellent in the polarization axis directions (4 directions) of the polarizing plate. This characteristic is
The same applies to the liquid crystal display devices of the above modes.

In particular, in a liquid crystal display element in which liquid crystal molecules are arranged in axial symmetry for each picture element, the disclination occurs because the liquid crystal molecules are continuously aligned in the picture element (in the liquid crystal region). Lines do not occur, light leakage does not occur when a saturation voltage is applied, and the contrast is high, which is particularly preferable.

(Driving Method) Driving methods that can be used to drive the liquid crystal display device of the present invention include simple matrix driving and a-Si.
A driving method such as active driving of TFT, p-Si.TFT, MIM, etc. can be used and is not particularly limited.

(Substrate material) As a substrate material used for a liquid crystal panel which constitutes a liquid crystal display element, a transparent solid glass, a polymer film, or the like, or in the case of a reflective LCD, as a substrate on the reflective side, A substrate with a metal thin film, a Si substrate or the like can be used.

As the plastic substrate, a material which does not absorb visible light is preferable, and PET, acrylic polymer, styrene, polycarbonate, etc. can be used.

Further, two kinds of these substrates may be combined to form a liquid crystal cell using different kinds of substrates, or two substrates having the same kind and different kinds but different in substrate thickness may be used by being roughened. .

However, it is needless to say that it is preferable to make the substrate materials and thicknesses of a plurality of panels constituting a single liquid crystal display element uniform so as to conceal the joint portion of these panels.

Further, in the case of a plastic substrate, it is possible to manufacture a liquid crystal display device in which a polarizing plate and a retardation plate are integrated by giving the substrate itself a polarizing ability and a retardation.

The embodiments of the present invention will be specifically described below. The present invention is not limited to these embodiments.

(Embodiment 1) First, for example, 1.1 mm
A transparent electrode made of ITO (a mixture of indium oxide and tin oxide) is formed on one surface of two thick glass substrates with a thickness of 1
It is formed to 50 nm. It should be noted that two glass substrates configured in advance as described above may be used.

Next, the above two glass substrates were opposed to each other with the transparent electrode inside, and a cell thickness was maintained by interposing a spacer of 5 μm therebetween to form a cell.

Next, as shown in FIG. 7, a photomask having a light-shielding portion b and a light-transmitting portion c is arranged on the fabricated cell so that the picture element portion is shielded, and further displayed in the cell. The medium-forming mixture is capillary injected. Examples of the mixture include 0.40 g of isobornyl acrylate, 0.40 g of isobornyl methacrylate, 0.10 g of p-phenylstyrene, 0.10 g of compound A shown below, and liquid crystal material ZLI-4792. (Merck: Δn = 0.09
4) 4 g and a photoinitiator (Irugacure651)
Was uniformly mixed with 0.025 g. The composition is not limited to this, and other compositions can be used.

[0053]

Embedded image

Either the arrangement of the photomask or the injection of the mixture may be performed first.

Next, while maintaining the cell temperature at 100 ° C., a parallel light beam was obtained at 10 mW / under a high pressure mercury lamp.
Irradiation was performed from the photomask side for 5 minutes while applying a voltage of ± 4 V between the transparent electrodes with the cell placed at cm ² . In this state, the ultraviolet rays are applied to the cell as a spatially regular pattern.

Next, with the voltage applied, for example, 10 ° C.
The cell temperature is set to 2 by gradually cooling the cell at a cooling rate of / hr.
The temperature was set to 5 ° C. (the liquid crystal was in a nematic state), and ultraviolet rays were continuously irradiated for another 3 minutes to cure the resin. When the manufactured cell was observed with a polarization microscope, it was observed that a photomask-like liquid crystal region g was formed as shown in FIG. 8 and was in a spiral alignment state around the central axis. . In FIG. 8, d is a pixel region, e is a polymer wall, and f is a quenching pattern.

A liquid crystal display device was produced by connecting the liquid crystal panels produced as described above, and a polarizing plate was provided to the liquid crystal display device as shown in FIG. 2 (a).

(Embodiment 2) A glass substrate (TF) having a thickness of 1.1 mm using ITO (a mixture of indium oxide and tin oxide, thickness of 1500 Å) as a transparent electrode.
OMR-83 (manufactured by Tokyo Ohka Co., Ltd.) on the TFT substrate by using two substrates (T-formed substrate and color filter formed substrate)
A resist was used to form a wall having the structure shown in FIG.

Next, using the two substrates prepared,
A cell was constructed by keeping the cell thickness with a spacer of m.

The mixture was then capillary injected into the cell.
As a mixture, 0.20 g of R-684, 0.20 g of p-phenylstyrene and 0.10 g of the compound A.
And liquid crystal material ZLI-4792 (manufactured by Merck: Δn =
0.094) with 4.5 g, and a photoinitiator (Irugacu
re651) is uniformly mixed with 0.025 g.

Then, once, the temperature is raised to a uniform phase,
The temperature was lowered so that the liquid crystal area became one for each picture element.

After that, a voltage of ± 5.0 V was applied between the transparent electrodes to establish an axially symmetric orientation state. From this state, the temperature was lowered to room temperature. In this state, 3 mW / cm ² (365 nm) under high pressure mercury lamp to fix the alignment state
It was irradiated there for 30 minutes. Then, ultraviolet rays were continuously irradiated for 20 minutes to cure the resin.

When the produced cell was observed with a polarization microscope, it was observed that a liquid crystal region was formed according to the resist pattern as shown in FIG. 10 and was in an axially symmetrical orientation state around the central axis. Was done.

The produced TFT panel is subjected to a dicing method to form two liquid crystal panels 2 as shown in FIG. 11 (a).
One side is cut off at the portion indicated by 17 and is shown in FIG.
As shown in, two liquid crystal panels 2 were bonded together. In FIG. 11, 10 indicates a picture element and 11 indicates a black matrix.

As shown in FIG. 11 (c), the liquid crystal display element thus produced was arranged so that the polarization axes thereof were orthogonal to each other and the polarization axis of the polarizing plate was in the same direction as the seam of the joint surface. The polarizing plates were attached together.

The viewing angle characteristics of the manufactured cell were as shown in FIG. When observing with the viewing angle down, the seams were at a level where they were almost invisible. Further, as understood from FIG. 6, in the direction of the polarization axis of the polarizing plate, the viewing angle characteristics are excellent, and the viewing angle symmetry as a whole of the liquid crystal display device makes the liquid crystal display device easy to see.

(Embodiment 3) Spin coating method using two 1.1 mm thick glass substrates (TFT substrate and color filter substrate) using ITO (mixture of indium oxide and tin oxide, thickness 1500 Å) as transparent electrodes. Was coated with nylon 66 to prepare a substrate having a spherulite structure on the substrate. Using the manufactured substrate,
A cell was constructed by keeping the cell layer with a spacer of 5 μm.

Liquid crystal material ZLI-4792 was placed in the cell.
(Manufactured by Merck & Co .: adjusted with a chiral agent S-811 so that the spiral pitch is 90 °) was injected. The liquid crystal molecules in the liquid crystal element were oriented in axial symmetry along the spherulite structure on the substrate.

As in the second embodiment, two liquid crystal panels were attached to each other, polarizing plates were attached to each other in the same manner, and the observation was performed with the viewing angle tilted. As a result, the seams were almost invisible. Further, in the direction of the polarization axis of the polarizing plate, the viewing angle characteristics are excellent, and the viewing angle symmetry as a whole of the liquid crystal display device,
It was an easy-to-read liquid crystal display device.

(Embodiment 4) Spin coating method using two 1.1 mm thick glass substrates (TFT substrate and color filter substrate) using ITO (mixture of indium oxide and tin oxide, thickness 1500 Å) as transparent electrodes. Was coated with polyimide and used without rubbing.

Using the produced substrate, a cell was constructed by keeping a cell layer with a spacer of 5 μm.

Liquid crystal material ZLI-4792 was placed in the cell.
(Manufactured by Merck & Co .: adjusted with a chiral agent S-811 so that the spiral pitch is 90 °) was injected. The liquid crystal molecules in the liquid crystal element were in a random alignment state because the alignment regulating force on the substrate was small.

Further, as in the second embodiment, two liquid crystal panels were bonded together, polarizing plates were bonded in the same manner, and the viewing angle was tilted to observe. As a result, the seams were almost invisible. Further, in the polarization axis direction of the polarizing plate, the liquid crystal display device is excellent in viewing angle characteristics and has a viewing angle symmetry as a whole liquid crystal display device, which is easy to see.

(Embodiment 5) A polyimide alignment film is coated on two 1.1 mm-thick glass substrates having ITO (a mixture of indium oxide and tin oxide, thickness of 1500 Å) as transparent electrodes, and a nylon cloth is applied. The rubbing treatment was performed in one direction. Spacers (5 μm) so that the rubbing directions of the treated substrates are orthogonal to each other
A bonded cell was produced via the. Liquid crystal material ZLI-4792 (chiral pitch 70μ
m) was injected in a vacuum to fabricate a TN cell.

As in the second embodiment, two liquid crystal panels were attached to each other, polarizing plates were attached to each other in the same manner, and the observation was performed with the viewing angle tilted. As a result, the seams were almost invisible.

(Comparative Example 1) Similar to the fifth embodiment, two sets of TFT-TN panels are produced and bonded (joined).
I went. The polarization axis of the polarizing plate is 45 ° with respect to the bonding surface.
And the polarizing plates on the upper and lower sides of the substrate were laminated so as to be orthogonal to each other. When observing with the viewing angle tilted, light leaked from the seam and the seam was completely visible.

[0077]

As described above in detail, in the case of the present invention, a liquid crystal display element having a display section in which a plurality of liquid crystal panels are joined and arranged in parallel is provided on both sides of the liquid crystal display element sandwiched in the thickness direction. Since at least one of the polarizing plates to be used has its polarization axis substantially aligned with the direction along the joint, the joint can be made invisible. Therefore, CR
It is possible to provide a liquid crystal display device as a large-sized flat display that can counter T.

Further, by using a liquid crystal display device having a wide viewing angle display mode, it can be used as a display device such as a large-sized high-definition liquid crystal display device or a portable information terminal device. In particular, it is effective in a liquid crystal display device used by 2 to 4 people at the same time.

[Brief description of drawings]

1A is a diagram showing a configuration of a liquid crystal display element of the present invention, and FIG. 1B is a diagram showing a polarization axis direction of a polarizing plate attached to the liquid crystal display element.

2A is a perspective view showing a liquid crystal display device of the present invention, FIG. 2B is a diagram showing a direction of linearly polarized light immediately after a polarizing plate on an illumination side, and FIG. Is a view showing the direction of light (preserving the plane of polarization), and (d) is a view showing light immediately after the observation-side polarization plate.

FIG. 3 is a diagram showing the concept of light passage through a joint surface (in the case of having birefringence) in a conventional liquid crystal display device, which is the same as FIG.

FIG. 4 is a diagram showing a relationship between how to attach a polarizing plate and viewing angle characteristics in a TN mode.

FIG. 5 is a diagram for explaining an advantage when using a liquid crystal display element in a wide viewing angle display mode in the present invention.

FIG. 6 is a diagram illustrating viewing angle characteristics when an axially symmetric alignment mode liquid crystal display element is used in the present invention.

FIG. 7 is a plan view showing a photomask used in the first embodiment.

8 is a plan view showing a state of the liquid crystal panel obtained in Embodiment 1. FIG.

9 is a plan view showing a resist material formed on a TFT substrate used in Embodiment 2. FIG.

FIG. 10 is a plan view showing an alignment state (observation example with a polarization microscope) of the liquid crystal display element obtained in Embodiment 2.

FIG. 11 is a diagram showing a method for joining liquid crystal panels in the present invention.

12A is a perspective view showing a conventional liquid crystal display device, FIG. 12B is a diagram showing the direction of linearly polarized light immediately after the illumination side polarization plate, and FIG. 12C is a view immediately after passing through the joint surface. FIG. 6 is a diagram showing the direction of light (preserving the polarization plane), and FIG.

FIG. 13 is a diagram showing a difference in reflectance between S waves and P waves on a reflecting surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2 Liquid crystal panel 3 Bonding surface 4, 5 Polarizing plate 10 Picture element 11 Black matrix

Claims (6)

[Claims] 1. A polarized light of at least one of polarizing plates provided on both sides of the liquid crystal display device, comprising a liquid crystal display device having a display portion in which a plurality of liquid crystal panels are joined and arranged in parallel. A liquid crystal display device in which a plate is installed so that its polarization axis substantially coincides with a direction along a joint between the plurality of liquid crystal panels forming the liquid crystal display element. 2. The liquid crystal panel according to claim 1, wherein the liquid crystal panel has a plurality of liquid crystal regions separated by polymer walls, and each liquid crystal region is arranged such that liquid crystal molecules are aligned in two or more directions. The described liquid crystal display device. 3. The alignment direction of liquid crystal molecules is set on at least one of the two substrates provided in the liquid crystal panel.
The liquid crystal display device according to claim 1, further comprising an aligning unit that is oriented in a direction or more. 4. The liquid crystal panel, an alignment layer is formed on at least one of two substrates provided in the liquid crystal panel in contact with a liquid crystal region, and the alignment layer is formed of a crystalline polymer. The liquid crystal display device according to claim 3, which is configured to have a spherulite structure. 5. The liquid crystal panel is configured such that an alignment layer provided on at least one of the two substrates provided in the liquid crystal panel is in a non-aligned state and the liquid crystal regions are randomly aligned. Item 4. The liquid crystal display device according to item 3. 6. The liquid crystal display device according to claim 2, wherein the liquid crystal panel has a configuration in which the alignment state of liquid crystal molecules is axially symmetrical.