JP3522845B2 - LCD panel - 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 panel for displaying an image, and more particularly to a liquid crystal display panel having high display quality.

[0002]

2. Description of the Related Art In recent years, among liquid crystal display devices, in order to obtain an image with particularly high display quality, active matrix drive type display devices using thin film transistors as switching elements have been actively developed. This is because a high contrast ratio can be obtained regardless of the number of scanning electrodes as compared with a simple matrix driving method without a switching element, and thus a clear image can be obtained even in a large-capacity display with high resolution.

In such an active matrix type liquid crystal display device, a TN (Twisted Nematic) type NW (Normally W) mode is widely used.
hite) mode is available. The TN method is a liquid crystal panel in which liquid crystal molecules are twisted by 90 ° between substrates, and is sandwiched by two polarizing plates. In addition, the polarization axes of the two polarizing plates are orthogonal to each other, and one polarizing plate is bonded so that the polarization axis is parallel or perpendicular to the long axis direction of the liquid crystal molecules in contact with one substrate. The matching mode is the NW mode. In the TN NW mode, white is displayed when no voltage is applied between the substrates or a low voltage is applied near a certain threshold voltage, and black is displayed at a higher voltage.

The display image is obtained in this way because when a voltage is applied to the liquid crystal panel, the liquid crystal molecules try to align themselves in the direction of the electric field while unwinding the twisted structure, and the molecules pass through the panel depending on the alignment state. This is because the polarization characteristics of the incoming light change and the light transmittance is modulated. It is the birefringence of the liquid crystal that has the effect of changing the polarization characteristics, but the liquid crystal molecules normally used in the TN mode are likened to rods, and the rod-shaped molecule has one optical axis in the long axis direction. It is a birefringent medium and has a refractive index of 2 in the major axis direction as shown in FIG.
Reference numeral 2 has an index ellipsoid 24 for the liquid crystal molecules 4, which is larger than the refractive index 23 in the minor axis direction.

By the way, as an amount for determining the polarization characteristic,
Refractive index anisotropy Δ with respect to the ray traveling direction 25 in FIG.
There is a retardation R = Δn ′ · d ′, which is the product of n ′ and the thickness d ′ of the liquid crystal layer. The size of Δn ′ is expressed as the difference between the lengths of the major axis 26 and the minor axis 27 of the ellipse represented by the intersection of the plane having the ray traveling direction 25 as the normal and the refractive index ellipsoid 24. You can

In the TN mode NW mode, when a sufficiently high voltage is applied, ideally all liquid crystal molecules have their major axes oriented in the voltage application direction (the substrate normal direction). Therefore, the light incident in the normal direction to the substrate travels exactly in the optical axis direction of the liquid crystal molecules, so Δn ′ = 0, and the retardation R does not occur. Therefore, the liquid crystal panel does not cause any change in the linearly polarized light polarized by the incident side polarization plate, is completely shielded by the emission side polarization plate, and does not transmit light, so that a completely black display is obtained.

[0007]

The conventional TN type liquid crystal display device in the NW mode has the following problems. In the NW mode, when a voltage is applied and the liquid crystal molecules rise completely perpendicular to the substrate surface, the liquid crystal molecules become true black when viewed from the direction perpendicular to the substrate. However, even if the liquid crystal molecules completely rise in this way, if light is incident at an angle that is offset from the azimuth of the polarization axis of the polarizing plate and at an angle that is tilted with respect to the substrate normal, it will no longer be true black. Disappear. In the NW mode, this phenomenon is most prominent in the direction deviated from the polarization axis by 45 °. This is because such obliquely incident light travels with an inclination with respect to the optical axis of the liquid crystal molecules, and therefore Δn ′ does not become 0, and therefore the retardation R also becomes 0, which changes the incident linearly polarized light. This is because it has a component that slightly passes through the emission side polarization plate and does not become true black.

Now, in the TN type of NW mode, as shown in FIG.
As shown in 0, in a liquid crystal panel on which it is assumed that all the liquid crystal molecules 4 have risen in the substrate normal direction 9 ideally, in a direction deviated by 45 ° from the polarization axis 7a of the incident side polarization plate 8a and in the substrate normal line. On the other hand, assume that a light ray 28 having an incident angle θ is incident. At this time, the incident linearly polarized light passes through the liquid crystal panel,
As shown in FIG. 11, between the transmittance T after passing through the exit side polarizing plate 8b having the polarization axis 7b orthogonal to the polarization axis 7a of the entrance side polarizing plate 8a and the incident angle θ. Have a relationship. Δn · d = 0.5 μm of the liquid crystal panel at this time
Is.

From FIG. 11, in the TN system NW mode,
It can be seen that when black display is performed, the incident angle dependency, that is, the viewing angle dependency is extremely large. In reality, even if a considerable voltage is applied, the liquid crystal molecules near the substrate interface have a strong interaction with the substrate and are hard to rise, and the liquid crystal molecules in the center of the liquid crystal layer do not completely rise. The dependence is even more pronounced.

As described above, since the liquid crystal panel having a large viewing angle dependency has a different display screen brightness depending on the viewing angle, the display quality is greatly impaired and is difficult to see. In view of the above problems, it is an object of the present invention to provide a liquid crystal display panel that can realize a display with little viewing angle dependency during black display.

[0011]

A liquid crystal display panel according to claim 1, wherein a plurality of striped insulating films are provided on the surface,
A first substrate having first and second electrodes provided in parallel on adjacent insulating films among the plurality of insulating films, and a first substrate facing the first substrate with the surface of the first substrate inside. No. 2 substrate, a nematic liquid crystal sandwiched between the first and second substrates and in which liquid crystal molecules are aligned in the horizontal direction with respect to the substrate surface, and polarization axes of the nematic liquid crystals arranged on both outer sides of the first and second substrates. And a pair of polarizing plates which are orthogonal to each other, and a voltage is applied between the first and second electrodes.

According to another aspect of the liquid crystal display panel of the present invention, a striped first insulating film is provided on the surface, and a linear first electrode is provided on the first insulating film. A stripe-shaped second insulating film is provided on the surface, and a second substrate having a linear second electrode provided on the second insulating film and the surfaces of the first and second substrates are set inside. A nematic liquid crystal in which liquid crystal molecules are aligned horizontally with respect to the substrate surface and sandwiched between opposed substrates; and a pair of polarizing plates disposed on both outer sides of the first and second substrates and having polarization axes orthogonal to each other. Equipped with
The first electrode and the second electrode are arranged in parallel at a position displaced from the facing position, and a voltage is applied between the first and second electrodes.

According to a third aspect of the present invention, in the liquid crystal display panel according to the first or second aspect, the liquid crystal molecule major axis direction of the nematic liquid crystal is substantially parallel to the first and second electrodes. It is characterized in that a horizontal alignment treatment is performed on the first and second substrates. The liquid crystal display panel according to claim 4, wherein a first insulating film is provided in a region excluding a plurality of display regions arranged in a matrix on the surface, and a linear shape corresponding to each display region is provided on the first insulating film. The picture element electrode of
A common electrode parallel to the pixel electrode is provided on the first insulating film with a display region interposed therebetween, a switching element connected to the pixel electrode is provided on the first insulating film, and switching is performed on the first insulating film. A first substrate provided with a signal electrode for supplying a signal to the pixel electrode through the element and a gate electrode for performing switching control of the switching element on the first insulating film; and the surface of the first substrate inside A second substrate disposed opposite to the first substrate, a nematic liquid crystal having liquid crystal molecules aligned between the first and second substrates in a horizontal direction with respect to the substrate surface, and both outer sides of the pair of substrates. And a pair of polarizing plates which are arranged in the same direction and whose polarization axes are orthogonal to each other.

According to another aspect of the liquid crystal display panel of the present invention, a first insulating film is provided in a region excluding a plurality of display regions arranged in a matrix on the surface, and each display region is provided on the first insulating film. A linear pixel electrode, a switching element connected to the pixel electrode on the first insulating film, and a signal for supplying a signal to the pixel electrode via the switching element on the first insulating film. A first electrode provided with a gate electrode for performing switching control of the switching element on the first insulating film
And a second substrate in which a second insulating film is provided in a region other than the display region on the surface, and a common electrode parallel to the pixel electrode is provided on the second insulating film with the display region interposed therebetween. Nematic liquid crystal in which liquid crystal molecules are aligned in the horizontal direction with respect to the substrate surface and sandwiched between the substrates which face each other with the surfaces of the first and second substrates facing inside, and the nematic liquid crystal is disposed on both outsides of the first and second substrates And a pair of polarizing plates whose polarization axes are orthogonal to each other.

A liquid crystal display panel according to a sixth aspect is the liquid crystal display panel according to the fourth or fifth aspect, wherein the liquid crystal molecule major axis direction of the nematic liquid crystal is substantially parallel to the common electrode and the pixel electrode. And a horizontal alignment treatment is performed on the second substrate.

[0016]

According to the structure of the present invention, the first members arranged in parallel are
By applying a voltage between the second electrode and the second electrode, or by applying a voltage between the common electrode and the pixel electrode, which are arranged in parallel with each other across the display region, the voltage is substantially horizontal to the substrate. Is applied. For this reason, the liquid crystal molecules horizontally aligned on the substrate rotate in a manner such that the long axis of the liquid crystal molecules is aligned with the rotation axis of the substrate normal direction as the voltage application increases.
Then, when a high voltage is applied, the liquid crystal molecules tend to face the electric field direction. Due to the deformation of the liquid crystal molecules due to such voltage application, the polarization of light passing through the liquid crystal panel is modulated,
It can be displayed.

Now, as shown in FIG. 4, the direction of the long axis of the liquid crystal molecules 4 horizontally aligned when no voltage is applied, and the polarization of the incident side polarization plate 8a of the polarization plates attached to both surfaces of the liquid crystal panel. The directions of the shafts 7a are arranged in the same direction. Then, the exit side polarization plate 8
If the polarization axis 7b of b is arranged orthogonal to this, black display can be obtained at this time. In this black display, when changing the incident angle θ of the light ray 28 incident on the liquid crystal panel,
If the direction to be changed matches the direction of the polarization axis,
Since birefringence due to the liquid crystal molecules 4 does not occur at all, it is possible to obtain black that is the same as black when vertically incident. On the other hand, with respect to the incident angle θ, the most prominent azimuth in which this black state floats white and changes is 45 with respect to the polarization axis.
It is in the direction of °. Even in the viewing angle dependency due to black display in this most intense azimuth, the change in the transmittance with respect to the incident angle θ is as shown in FIG. It can be seen that black display with a very wide viewing angle is obtained without any change.

On the other hand, the molecular deformation when a voltage is applied is as follows. The orientations of liquid crystal molecules at the interfaces of the upper and lower substrates are the same or are oriented 180 degrees. The liquid crystal molecules at the substrate interface do not move because they are strongly bound by the alignment regulating force. However, the liquid crystal molecules between the substrates are twisted in a larger direction as they are separated from one of the substrates, and have an orientation perpendicular to the electrodes at a certain portion between the substrates. Then, when it further approaches the other substrate, it twists in a direction opposite to a certain direction, and the liquid crystal molecules have the initial orientation at the interface of the other substrate. With such an alignment state, white display is obtained.

By the way, when the electrodes are formed on one substrate, the electric field is stronger near one substrate and weaker near the other substrate. At this time, the liquid crystal molecules on one of the substrates do not move in spite of the strong electric field due to the strong alignment regulating force. Therefore, the molecular deformation between the substrates may not be largely twisted for the applied voltage, and the polarization modulation may be small. This implies that the display is not very bright even when a high voltage is applied. Therefore, in the present invention, the electrode is not directly provided on the substrate, but an insulating film having a desired thickness is formed on the substrate and then the electrode is formed on the insulating film. Further, if the insulating film between the electrodes is removed, the electrodes can be formed at a position separated from both the upper and lower substrates, and the liquid crystal molecules are filled up to the interface between the substrates. Therefore, since the liquid crystal molecules in the portion having the highest electric field strength are far from the substrate interface, they can be largely deformed without being constrained.

From the above, according to the configuration of the present invention,
A very bright display can be realized. If the gap between the substrate and the electrode, that is, the thickness of the insulating film is too thin, no effect is obtained. Therefore, when the thickness of the liquid crystal layer filled in the gap between the substrates is 3 μm or more, at least 0.5 μm or more. is necessary.

[0021]

【Example】

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a sectional view showing the configuration of a liquid crystal display panel according to a first embodiment of the present invention.
FIG. 3B is a plan view of the configuration of the liquid crystal display panel.

In this embodiment, a nematic liquid crystal in which liquid crystal molecules 4 are aligned horizontally with respect to the substrate surface is sandwiched between a substrate (first substrate) 1a and a substrate (second substrate) 1b. There is. On the inner side surface of one substrate 1a, a plurality of silicon nitride films (insulating films) formed in stripes excluding the display region.
20 and first and second electrodes 2A and 2B which are arranged in parallel on the adjacent silicon nitride film 20 with the display region interposed therebetween. A pair of polarizing plates 8a and 8b (FIG. 3) whose polarization axes 7a and 7b (FIG. 3) are orthogonal to each other are provided on both outer sides of the pair of substrates 1a and 1b, and a voltage is applied between the electrodes 2A and 2B. I am trying to do it. The rubbing-processed polyimide alignment films 3a and 3b are formed on the substrates 1a and 1b so that the long axis direction of the liquid crystal molecules 4 is substantially parallel to the electrodes 2A and 2B.
It is provided above.

FIG. 2 shows the electrode 2 of this liquid crystal display panel.
It is a figure which shows the whole structure of A and 2B. In this Figure 2,
One ends of the first electrodes 2A are short-circuited to each other, and the first electrodes 2A are used as scanning electrodes, and the second electrodes 2B are used as signal electrodes.
One pixel region 30 is formed between the first electrodes 2A and 2A. A method of manufacturing the liquid crystal display panel having the above structure will be described.

First, a silicon nitride film having a thickness of about 500 nm was formed on the transparent glass substrate 1a by the plasma CVD method, and then aluminum was deposited on the entire surface to a thickness of about 1 μm. Next, the width is 5 μm and the linear pattern is 15 μm.
Aluminum was patterned by photolithography using the masks drawn at intervals of m to form electrodes 2A and 2B. Further, using a mask having a width of 7 μm and linear patterns drawn at intervals of 13 μm, the silicon nitride film is patterned by photolithography so that the silicon nitride film 20 immediately below the aluminum electrodes 2A and 2B remains. I went. As a result, as shown in FIG. 1, on the silicon nitride film 20 having a width of 6 μm and a height of 500 nm,
Aluminum electrodes 2A and 2B having a width of 4 μm and a height of 1 μm were formed with a space of 16 μm. This electrode 2A, 2
The polyimide alignment film 3 is formed on the entire surface of the substrate 1a on which B is formed.
A was applied by a printing method, cured and dried, and then a rubbing treatment was performed using a rayon cloth in a direction parallel to the electrodes 2A and 2B at an angle of about 1 °. Further, glass beads 18 having a particle diameter of 4.5 μm were dispersed on the glass substrate 1a.

The other transparent glass substrate 1b was also coated with the polyimide alignment film 3b, cured and dried, and then rubbed with a rayon cloth. At this time, the rubbing treatment was carried out in such a direction that the liquid crystal molecules would be in a homogeneous alignment when it was attached to the substrate 1a on which the electrodes 2A and 2B were formed. The substrate 1a on which the electrodes 2A and 2B are formed and the other transparent glass substrate 1b.
And were pasted together with the surfaces on the side where the alignment films 3a and 3b are formed facing each other, and the upper and lower substrates 1a and 1b.
It was possible to fabricate cells with an interval of 5 μm maintained. ZLI-479 having a Δn of 0.095 made by a Merck company nematic liquid crystal in the cell thus manufactured
2 was injected into the gap of 5 μm to obtain a liquid crystal panel 5.

Next, as shown in FIGS. 3 and 4, parallel to the rubbing direction 6 (the long axis direction of the liquid crystal molecules 4 horizontally aligned when no voltage is applied) on one outer surface of the liquid crystal panel 5. The incident side polarization plate 8a having the polarization axis 7a is set so that the polarization axis 7b is formed on the other surface.
An emission side polarization plate 8b is provided so as to be orthogonal to the polarization axis 7a of a.

When light is made to enter in the substrate normal direction 9 of the liquid crystal panel 5 sandwiched between the polarizing plates 8a and 8b, the light is totally blocked by the emitting side polarizing plate 8b, and a good black display is obtained. Was obtained. In this black display, when the incident angle θ of the light ray 28 incident on the liquid crystal panel is changed and the direction of change is matched with the azimuth of the polarization axis 7a, birefringence due to the liquid crystal molecules 4 does not occur at all. It is possible to obtain black that is the same as black when vertically incident. On the other hand, with respect to the incident angle θ, the most prominent azimuth in which the black state floats and changes to white is the azimuth of 45 ° with respect to the polarization axis 7a.

Next, the polarization axes 7a and 4 of the incident side polarization plate 8a
When the incident angle θ of light was changed and the amount of light transmitted through the exit side polarization plate 8b was measured in the azimuth angle of 5 °, a transmittance-incident angle curve as shown in FIG. 5 was obtained. It was found that the transmittance was 10% or less within the incident angle of 40 °, that is, excellent black was obtained in a wide incident angle range, and the viewing angle characteristics were wide.

Next, when a rectangular wave of 30 Hz was applied between the aluminum electrodes 2A and 2B separated by 16 μm, the transmittance of the liquid crystal panel began to increase, and a very bright display was obtained at a voltage of about 6V. Was given. The brightness of the central portion at this time is the transmittance measured when the polarization axis 7b of the exit side polarization plate 8b is arranged parallel to the polarization axis 7a of the entrance side polarization plate 8a and no voltage is applied to the liquid crystal panel 5. Against 85%
It was found to have a transmittance of.

As described above, in the liquid crystal display panel of this embodiment, it was possible to obtain an excellent image in which both black and white were good, the contrast ratio was high, and the viewing angle characteristics during black display were wide. [Second Embodiment] A second embodiment of the present invention will be described below with reference to the drawings. FIG. 6A is a sectional view showing the configuration of a liquid crystal display panel according to the second embodiment of the present invention.
FIG. 3B is a plan view of the configuration of the liquid crystal display panel.

This embodiment differs from the first embodiment in that
The polyimide film 21 is formed instead of the silicon nitride film 20 as an insulating film between the electrodes 2A and 2B and the substrate 1a. The other structure is similar to that of the first embodiment.
A method of manufacturing the liquid crystal display panel of this embodiment will be described. The difference from the first embodiment is that the process of forming the insulating film is not forming the silicon nitride film by plasma CVD but applying polyimide by a printing method. An intaglio offset method was used for printing. The width of the intaglio plate is 8 μm
In which linear grooves having a pitch of 12 μm are formed. First, the polyimide precursor solution on the intaglio plate was transferred onto the transparent glass substrate 1a by a silicon blanket. After that, the polyimide film 21 was formed by heating at 250 ° C. for about 1 hour and curing. The thickness of the obtained polyimide film 21 is about 0.5 μm, and the width is about 10 μm and 10 μm.
Were formed at intervals of. Next, aluminum is vapor-deposited on the entire surface to a thickness of about 1 μm, and then aluminum is placed directly on the polyimide film 21 using a mask having a width of 5 μm and linear patterns drawn at intervals of 15 μm. Patterning was performed so as to remain, and electrodes 2A and 2B were formed. As a result, as shown in FIG. 6, width 10 μm and height 0.5 μ
Aluminum electrodes 2A and 2B having a width of 4 μm and a height of 1 μm were formed on the polyimide film 21 having a width of 16 μm with a space of 16 μm.

Substrate 1a on which the electrodes 2A and 2B are formed
Then, a polyimide alignment film 3a is applied to the entire surface of the substrate by a printing method, and after curing and drying, a rayon cloth is used to form the electrode 2
The rubbing treatment was performed in the direction parallel to the directions A and 2B so as to form an angle of about 1 °. Further, glass beads 18 having a particle diameter of 4.5 μm were dispersed on the glass substrate 1a. Also on the other transparent glass substrate 1b, the polyimide alignment film 3
After b was applied and cured and dried, rubbing treatment was performed using a rayon cloth. At this time, the rubbing treatment was carried out in such a direction that the liquid crystal molecules would be in a homogeneous alignment when it was attached to the substrate 1a on which the electrodes 2A and 2B were formed.

The substrate 1a on which the electrodes 2A and 2B are formed and the other transparent glass substrate 1b are attached to each other with the surfaces on the sides on which the alignment films 3a and 3b are formed facing each other. , 5μ between the upper and lower substrates 1a and 1b
It was possible to fabricate cells having a distance of m. 5 μ of ZLI-4792 having a Δn of 0.095, which is a nematic liquid crystal manufactured by Merck & Co., was applied to the cell thus manufactured.
Then, the liquid crystal panel 5 was obtained.

Next, as in the first embodiment, as shown in FIG. 3, an incident-side polarization plate in which a polarization axis 7a is set on one outer surface of the liquid crystal panel 5 so as to be parallel to the rubbing direction 6. 8a is provided, and on the other surface, an outgoing side polarizing plate 8b is provided so that the polarizing axis 7b is orthogonal to the polarizing axis 7a of the incident side polarizing plate 8a. When light was made to enter in the substrate normal direction 9 of the liquid crystal panel 5 sandwiched between such polarizing plates 8a and 8b, the light was completely blocked by the emitting side polarizing plate 8b, and good black display was obtained. . Next, the polarization axis 7 of the incident side polarization plate 8a
When the incident angle of light was changed and the amount of light transmitted through the exit side polarizing plate 8b was measured in the azimuth forming an angle of 45 ° with a, the same transmittance as in FIG. 5 of the first embodiment was obtained. −
An incident angle curve was obtained, and it was also found that the viewing angle characteristics were wide.

Next, when a rectangular wave of 30 Hz was applied between the aluminum electrodes 2A and 2B separated by 16 μm, the transmittance of the liquid crystal panel started to increase, and when the voltage was about 6 V, it was the same as in the first embodiment. A very bright display was obtained as well. As described above, according to the first and second embodiments,
By applying a voltage between the first and second electrodes 2A and 2B arranged in parallel with the display region in between, the substrate 1a,
A voltage is applied substantially horizontally to 1b. For this reason, the liquid crystal molecules 4 horizontally aligned on the substrate can rotate in a motion such that the long axis thereof is the rotation axis of the substrate normal direction 9 as the voltage application increases. In particular, the viewing angle characteristics during black display can be greatly expanded,
Moreover, since the brightness of the display image can be continuously changed according to the magnitude of the applied voltage, it is possible to obtain a high-quality image display capable of gradation display.

In the first and second embodiments, the electrode 2
Silicon nitride film 2 as an insulating film between A and 2B and substrate 1a
0, the polyimide film 21 was used, but in addition, methacrylic resin used for color filters, polyurethane resin,
Alternatively, a pattern such as an acrylic resin can be formed by printing, and a liquid crystal display panel having a similar structure can be manufactured.
Further, in the first and second embodiments, the electrodes 2A and 2B and the insulating films (20 and 21) are arranged only on the one substrate 1a, but the first electrode 2A is formed on the substrate 1a and The two electrodes 2B may be formed on the substrate 1b, and the first and second electrodes 2A and 2B may be arranged on the two substrates 1a and 1b while being displaced from the facing positions. In this case as well, an insulating film is arranged between the electrodes 2A and 2B and the substrates 1a and 1b.

[Third Embodiment] A third embodiment of the present invention will be described below with reference to the drawings. Figure 7
FIG. 7A is a structural plan view of a liquid crystal display panel of a third embodiment of the present invention, and FIG. 7B is a structural sectional view of the liquid crystal display panel. In this embodiment, a nematic liquid crystal in which liquid crystal molecules 4 are aligned in the horizontal direction with respect to the substrate surface is sandwiched between a substrate (first substrate) 1a and a substrate (second substrate) 1b. A silicon nitride film (insulating film) formed on the inner surface of one substrate 1a except for the display regions arranged in a matrix.
20 and a plurality of common electrodes 14 arranged in parallel on the silicon nitride film 20 with a display region interposed therebetween and short-circuited to each other, and arranged on the silicon nitride film 20 in parallel with each common electrode 14 with a display region interposed therebetween. A plurality of picture element electrodes 15, thin film transistors (switching elements) 13 arranged on the silicon nitride film 20 and connected to the picture element electrodes 15, and picture element electrodes arranged on the silicon nitride film 20 via the thin film transistors 13. A source electrode (signal electrode) 11 for supplying a signal to 15 and a gate electrode 10 arranged on the silicon nitride film 20 for controlling switching of the thin film transistor 13 are provided. Then, the polarization axes 7a and 7b of the pair of substrates 1a and 1b are provided on both outer sides of the substrates 1a and 1b.
A pair of polarizing plates 8a and 8b (Fig. 3) orthogonal to each other (Fig. 3) are provided. Further, the long axis direction of the liquid crystal molecules 4 is the common electrode 1
4 and a pixel electrode 15 are provided with a rubbing-treated polyimide alignment film (not shown) that is substantially parallel to the substrate 1.
It is provided on a and 1b.

A method of manufacturing the liquid crystal display panel having the above structure will be described. First, a silicon nitride film having a thickness of about 500 nm was formed on the glass substrate 1a. Next, chromium was vapor-deposited and the gate electrode 10 was formed by photoetching. Next, as a gate insulating film, silicon dioxide and silicon nitride are used as plasma C
The layers were laminated by the VD method to a thickness of about 200 nm. Further, similarly, an amorphous silicon layer was formed to a thickness of about 50 nm by the plasma CVD method. This amorphous silicon layer was photoetched to form a thin film transistor 13. Next, after forming aluminum to about 1 μm by vapor deposition, the source electrode 11 and the source electrode 11 are formed by photoetching.
A linear common electrode 14 short-circuited by a lead electrode (not shown) and a pixel electrode 15 were formed. After this, electrode 1
When the silicon nitride and the silicon dioxide in the portions without 0, 11, 14, and 15 are removed by photoetching, the electrodes 10, 11, and 1 are formed on the glass substrate 1a via the silicon nitride film 20.
It became the structure in which 4, 15, etc. were formed. In this embodiment, the silicon nitride film 2 seen from the cross section as shown in FIG.
The width of 0 is 28 μm, and the adjacent silicon nitride films 20, 20
Is 7 μm, the electrodes 11 on the silicon nitride film 20,
The width of 14 and 15 is 4 μm, and the height is 1 μm. Also,
Common electrode 1 formed on adjacent silicon nitride films 20 and 20
The distance between 4 and the pixel electrode 15 is 15 μm.

Next, a polyimide alignment film (not shown) is applied on the entire surface of the substrate 1a on which the electrodes are formed by a printing method, and after curing and drying, a rayon cloth is used to form the electrodes 1
The rubbing treatment was performed in a direction parallel to 4, 15 and an angle of about 1 °. The other transparent glass substrate 1b is coated with a polyimide alignment film (not shown),
After curing and drying, rubbing treatment was performed using a rayon cloth. At this time, the rubbing treatment was carried out in such a direction that the liquid crystal molecules 4 would be in a homogeneous alignment when it was attached to the substrate 1a on which the electrodes were formed. Further, glass beads 18 having a particle size of 3 μm were dispersed on the glass substrate 1b.

These substrate 1a on which electrodes are formed,
When the transparent glass substrate 1b in which the other glass beads 18 are dispersed is attached with the electrodes 10, 11, 14, 15 and the like inside, it is possible to fabricate cells with an interval of 4.7 μm. did it. The cell manufactured in this way was manufactured with a nematic liquid crystal manufactured by Merck and had Δn of 0.09.
No. 5, ZLI-4792, was injected into the gap of 4.7 μm to obtain a liquid crystal panel 5.

Next, as in the first embodiment, as shown in FIG. 3, an incident side polarization plate 8a having a polarization axis 7a set on one outer surface of the liquid crystal panel 5 so as to be parallel to the rubbing direction. Is provided on the other surface so that the polarization axis 7b is orthogonal to the polarization axis 7a of the incidence-side polarization plate 8a.
b is provided. When light is incident in the substrate normal direction 9 of the liquid crystal panel sandwiched between the polarizing plates 8a and 8b,
Light was completely blocked by the exit side polarizing plate 8b, and good black display was obtained. Next, when the incident angle of light was changed in the azimuth forming an angle of 45 ° with the polarization axis 7a of the incident side polarization plate 8a and the amount of light transmitted through the emission side polarization plate 8b was measured, The same characteristics as the transmittance-incidence angle curve of FIG. 5 of the example were obtained, and it was also found that the viewing angle characteristics were wide.

Next, for the gate electrode 10, 16.7 ms
An active matrix in which a rectangular wave whose polarity changes every 16.7 ms is applied between the source electrode 11 and the common electrode 14 while applying a scanning signal such that switching of the thin film transistor 13 is turned on for 30 μs each time. The liquid crystal panel 5 was operated by driving. Source electrode 11
-When the voltage amplitude of the rectangular wave between the common electrodes 14 is increased, the transmittance of the liquid crystal panel 5 starts to increase accordingly, and a very bright display is obtained when the effective voltage is about 5.5V. Was given. The brightness at this time had a transmittance of 90%, and it was found that a sufficiently bright white display was obtained.

[Fourth Embodiment] A fourth embodiment of the present invention will be described below with reference to the drawings. Figure 8
FIG. 8A is a structural plan view of a liquid crystal display panel of a fourth embodiment of the present invention, and FIG. 8B is a structural sectional view of the liquid crystal display panel. This embodiment is different from the third embodiment in that the common electrode 14 is arranged on the substrate 1b, and the silicon nitride film 20 'is arranged between the common electrode 14 and the substrate 1b. The other structure is similar to that of the third embodiment.

A method of manufacturing the liquid crystal display panel of this embodiment will be described. This embodiment is exactly the same as the third embodiment until the thin film transistor 13 is formed. In addition,
The silicon nitride film 20 corresponds to the first insulating film. After forming the thin film transistor 13, aluminum is deposited to a thickness of about 1 μm and the source electrode 1 is formed by photoetching.
1 and the pixel electrode 15 were formed. After this, as in the first embodiment, the silicon nitride and silicon dioxide in the portions where the electrodes 10, 11 and 15 were not formed were removed by photoetching. And
On the entire surface of the substrate 1a on which the electrodes 10, 11, 15 are formed,
Apply a polyimide alignment film (not shown) by printing,
After curing and drying, a rayon cloth is used to form the electrodes 11, 1
The rubbing treatment was performed in the direction parallel to the direction 5 and at an angle of about 1 °.

A silicon nitride film having a thickness of about 500 nm was formed on the other transparent glass substrate 1b. Next, after forming aluminum to about 1 μm, a linear common electrode 14 short-circuited by a lead electrode (not shown) was formed by photoetching. Then, the silicon nitride film is patterned by removing the silicon nitride film by photoetching (second insulating film)
20 '. A polyimide alignment film (not shown) was applied to the substrate 1b on which the electrode 14 was formed, and after curing and drying, a rubbing treatment was performed using rayon cloth.
The rubbing direction at this time is such that when the substrate 1a on which the electrodes 10, 11 and 15 are formed is bonded, the liquid crystal molecules 4 are formed.
Was oriented in a homogeneous orientation. Further, glass beads 18 having a particle diameter of 3 μm are formed on the glass substrate 1b.
Dispersed.

When the substrate 1a and the substrate 1b were attached to each other with the surfaces on which the electrodes were formed facing each other, cells having a distance of 4.7 μm could be produced. ZLI-4 having a Δn of 0.095 in a nematic liquid crystal manufactured by Merck Ltd.
792 was injected into the gap of 4.7 μm to obtain a liquid crystal panel 5.

Next, as in the first embodiment, as shown in FIG. 3, polarizing plates 8a and 8b are attached to both sides of the liquid crystal panel 5, and light is made incident in the substrate normal direction 9 of the liquid crystal panel 5. However, the output side polarization plate 8b blocked light at all, and a good black display was obtained. The transmittance-incidence angle curve is also similar to that of FIG. 5, and it was also found that the viewing angle characteristics are wide. next,
Similarly to the third embodiment, when the liquid crystal panel 5 was operated by active matrix driving, the source electrode 11
-When the voltage amplitude of the rectangular wave between the common electrodes 14 is increased, the transmittance of the liquid crystal panel 5 begins to increase accordingly, and a very bright display is obtained when the effective voltage is about 5.5V. Was given. The transmittance of the liquid crystal panel at this time is also 92
% Has been confirmed.

As described above, according to the third and fourth embodiments, by applying a voltage between the common electrode 14 and the pixel electrode 15 which are arranged in parallel with each other with the display region interposed therebetween, the substrate 1a, A voltage is applied substantially horizontally to 1b.
For this reason, the liquid crystal molecules 4 horizontally aligned on the substrate can rotate in a motion such that the long axis thereof is the rotation axis of the substrate normal direction 9 as the voltage application increases. In particular, the viewing angle characteristics during black display can be greatly widened, and the brightness of the display image can be continuously changed according to the magnitude of the applied voltage, so high-quality images that can be displayed in gradation are provided. It becomes possible to obtain a display.

In the third and fourth embodiments, an insulating film made of polyimide, methacrylic resin, polyurethane resin, acrylic resin or the like may be used instead of the silicon nitride films 20, 20 '. In addition, in the first to fourth embodiments, the silicon nitride films 20 and 20 'and the polyimide film 21 have a thickness of at least 0.5 μm when the thickness of the liquid crystal layer filled in the gap between the substrates is 3 μm or more. The above is necessary.

[0050]

As described above, according to the present invention, a voltage is applied between the first and second electrodes arranged in parallel, or a common electrode and a pixel electrode arranged in parallel with a display region interposed therebetween. By applying a voltage between and, a voltage is applied in a substantially horizontal direction with respect to the substrate. For this reason, the liquid crystal molecules horizontally aligned on the substrate can rotate in a manner such that the major axis thereof is the rotation axis in the direction normal to the substrate as the voltage application increases. Since the viewing angle characteristics at the time of display can be significantly widened and the brightness of the display image can be continuously changed according to the magnitude of the applied voltage, high-quality image display capable of gradation display can be achieved. It becomes possible to obtain.

[Brief description of drawings]

FIG. 1 is a structural sectional view and a structural plan view of a liquid crystal display panel of a first embodiment of the present invention.

FIG. 2 is a diagram showing the overall configuration of electrodes of the liquid crystal display panel of the first embodiment of the present invention.

FIG. 3 is a diagram showing an arrangement relationship between a polarizing plate and a liquid crystal panel of the liquid crystal display panel according to the first embodiment of the present invention.

FIG. 4 is a conceptual diagram showing optical characteristics of the liquid crystal display panel in the first embodiment of the present invention.

FIG. 5 is a view angle characteristic diagram in black display of the liquid crystal display panel according to the first embodiment of the present invention.

FIG. 6 is a structural sectional view and a structural plan view of a liquid crystal display panel of a second embodiment of the present invention.

FIG. 7 is a structural plan view and a structural sectional view of a liquid crystal display panel according to a third embodiment of the present invention.

FIG. 8 is a structural plan view and a structural sectional view of a liquid crystal display panel according to a fourth embodiment of the present invention.

FIG. 9 is a conceptual diagram showing optical characteristics of liquid crystal molecules.

FIG. 10 is a conceptual diagram showing optical characteristics of a conventional liquid crystal display panel.

FIG. 11 is a view angle characteristic diagram in black display of a liquid crystal display panel of a conventional example.

[Explanation of symbols]

1a, 1b substrate 2A First electrode 2B Second electrode 3a, 3b Polyimide alignment film 4 Liquid crystal molecules 5 LCD panel 6 rubbing direction 7a, 7b Polarization axis 8a, 8b Polarizing plate 9 Substrate normal direction 10 Gate electrode 11 Source electrode (signal electrode) 13 Thin film transistor (switching element) 14 common electrode 15 picture element electrode 18 glass beads 20 Silicon nitride film 20 'silicon nitride film 21 Polyimide film

Continuation of the front page (56) Reference JP-A-1-223415 (JP, A) JP-A-6-202127 (JP, A) JP-A-6-214244 (JP, A) JP-A-6-222397 (JP , A) JP 7-43744 (JP, A) JP 62-144137 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/13-1/141

Claims (6)

(57) [Claims] 1. A first substrate having a plurality of stripe-shaped insulating films provided on a surface thereof, wherein first and second electrodes are provided in parallel on adjacent insulating films of the plurality of insulating films; The first substrate is disposed so as to face the first substrate with the surface of the first substrate facing inward, and liquid crystal molecules are sandwiched between the first and second substrates and aligned in the horizontal direction with respect to the substrate surface. A nematic liquid crystal and a pair of polarizing plates disposed on both outer sides of the first and second substrates and having polarization axes orthogonal to each other are provided, and a voltage is applied between the first and second electrodes. Liquid crystal display panel. 2. A first substrate having a striped first insulating film provided on the surface thereof, and a linear first electrode provided on the first insulating film; and a striped second insulating film provided on the surface of the first substrate. It is sandwiched between a second substrate provided with an insulating film and a linear second electrode provided on the second insulating film, and a substrate arranged to face each other with the surfaces of the first and second substrates facing inward. A nematic liquid crystal in which liquid crystal molecules are aligned in the horizontal direction with respect to the substrate surface, and a pair of polarizing plates disposed on both outer sides of the first and second substrates and having polarization axes orthogonal to each other, A liquid crystal display panel in which the first electrode and the second electrode are arranged in parallel at a position displaced from the facing position, and a voltage is applied between the first and second electrodes. 3. A horizontal alignment process is performed on the first and second substrates so that the long axis direction of liquid crystal molecules of the nematic liquid crystal is substantially parallel to the first and second electrodes. Item 3. A liquid crystal display panel according to item 1 or 2. 4. A first insulating film is provided in a region other than a plurality of display regions arranged in a matrix on the surface, and linear picture element electrodes corresponding to the respective display regions are provided on the first insulating film. A common electrode parallel to the pixel electrode is provided on the first insulating film with the display region interposed therebetween, and a switching element connected to the pixel electrode is provided on the first insulating film; A signal electrode for supplying a signal to the pixel electrode via the switching element is provided on the first insulating film, and a gate electrode for performing switching control of the switching element is provided on the first insulating film. Substrate, a second substrate facing the first substrate with the surface of the first substrate inside, and a horizontal direction sandwiched between the first and second substrates and horizontal to the substrate surface. A nematic liquid crystal in which liquid crystal molecules are aligned, A liquid crystal display panel comprising a pair of polarizing plates arranged on both outer sides of a pair of substrates and having polarization axes orthogonal to each other. 5. A first insulating film is provided in a region excluding a plurality of display regions arranged in a matrix on the surface, and linear pixel electrodes corresponding to the respective display regions are provided on the first insulating film. A switching element connected to the pixel electrode is provided on the first insulating film, and a signal electrode for supplying a signal to the pixel electrode via the switching element is provided on the first insulating film. A first electrode provided on the first insulating film for controlling switching of the switching element,
And a second insulating film on the surface of the substrate except the display area,
A second substrate provided with a common electrode parallel to the pixel electrode on the second insulating film with the display region sandwiched between the second substrate and the substrates arranged to face each other with the surfaces of the first and second substrates inside. A nematic liquid crystal in which liquid crystal molecules are aligned in the horizontal direction with respect to the surface of the substrate, and a pair of polarizing plates disposed on both outer sides of the first and second substrates and having polarization axes orthogonal to each other. Liquid crystal display panel. 6. The horizontal alignment treatment is performed on the first and second substrates so that the long axis direction of the liquid crystal molecules of the nematic liquid crystal is substantially parallel to the common electrode and the pixel electrode. 4. The liquid crystal display panel according to 4 or 5.