JPH0961796A - Liquid crystal display panel and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wide visual field angle liquid crystal display panel which may be produced even if the panel is not subjected to rubbing treatments, has a high contrast and is capable of making uniform display. SOLUTION: This wide visual field angle liquid crystal display panel consists of the very small unit liquid crystal cells enclosed by a first high-polymer film 110 formed on the electrodes 103, 104 of substrates 101, 102 and a second high- polymer film 111 approximately perpendicular to these substrates 101, 102 and has at least one sheet of polarizing plate 107. The liquid crystal molecules on the surface of the substrate 101 have various bearings. The very small unit liquid crystal cell liquid crystals are composed of a chiral liquid crystal material having positive dielectric constant anisotropy.

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 and a manufacturing method thereof, and more particularly to a wide viewing angle liquid crystal display panel which does not require rubbing treatment and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, in a liquid crystal display panel, active matrix type liquid crystal display panels in which a thin film transistor is provided as a switching element in each pixel in order to obtain an image with high display quality are being actively developed. Compared to the simple matrix method, this method can obtain a high contrast ratio even if the number of scanning lines is increased, so it is rapidly adopted in the EWS that requires a large capacity and the video field that requires a clear image. Is progressing.

The TN (Twisted Nematic) system is widely used for such an active matrix type liquid crystal display panel. In this method, a liquid crystal panel having a structure in which liquid crystal molecules are twisted 90 degrees vertically is sandwiched between two opposing substrates by two polarizing plates. In the TN system, the two polarization axes are orthogonal to each other, and the polarization axes of the polarizing plates on the same side as the long axis direction of the liquid crystal molecules at the interface of one substrate are parallel or vertical. The NW (normally white) mode and the polarization axes of the two sheets are parallel to each other, and the polarization axes of the polarizing plates on the same side as the major axis direction of liquid crystal molecules at the interface of one substrate are parallel or vertical. There is a certain NB (normally black) mode.

Conventionally, in such a liquid crystal display panel, in order to align the orientation directions of liquid crystal molecules over the entire panel, a polymer organic thin film such as polyimide is formed on a substrate constituting the liquid crystal display panel, and nylon, polyester cloth, etc. A so-called rubbing process was performed by rubbing in a predetermined direction. As a result, a single alignment region (mono domain) is realized over the entire panel.

However, the above-mentioned rubbing treatment method has a problem of causing electrostatic breakdown, dust generation, or film contamination of the thin film transistor during rubbing, and therefore development has been made to eliminate the rubbing treatment process. For example, by applying photolithography technology, a method of forming microgrooves on a substrate and orienting a nematic liquid crystal (Kawata, Takagashira, Gizu, Sakamoto, Hasegawa: Proceedings of the 17th Liquid Crystal Symposium, 2F108), etc. Proposed.

Now, when the use of liquid crystal display panels is expanded and a large area and full color are required, the narrow viewing angle causes deterioration of display quality even in an active matrix type liquid crystal display panel. Things have been especially highlighted recently.

In the liquid crystal display device, when a voltage is applied between the upper and lower substrates, the liquid crystal molecules try to be aligned in the direction of the electric field while unwinding the twisted structure. The polarization state of the light passing through is changed, and the transmitted light is dimmed. For example, in the NW mode, white display is realized when no voltage is applied, and black display is realized when a sufficiently high voltage is applied. By the way, even if the spatial alignment of liquid crystal molecules is the same (constant applied voltage), the polarization state of light changes depending on the incident direction of the light entering the liquid crystal layer. The transmitted light intensity of light differs depending on the direction. Furthermore, the transmitted light intensity of the liquid crystal panel is determined by the alignment of the liquid crystal molecules located in the plane (midplane) that passes through the center of the liquid crystal layer between the two panel substrates and is parallel to the substrate. Is determined by the positional relationship between the tilting direction of the liquid crystal panel and the transmitted light observation direction of the liquid crystal panel.

In any of the above-mentioned rubbing method and photolithography method of liquid crystal alignment, the direction of inclination due to the electric field of the liquid crystal molecules located on the midplane is a constant direction with respect to the panel surface. A difference in birefringence, that is, a change in the polarization state of light passing through,
There was a problem with the viewing angle that the contrast and hue differ greatly depending on the viewing angle.

Therefore, in recent years, in the TN type liquid crystal display panel, a technique for expanding the viewing angle has been actively developed. As an example, a method of expanding a viewing angle by dividing a pixel of a TN type liquid crystal display panel into two regions (domains) having different alignment states (T.Takatori, K.Sumiyoshi, Y.Hirai, SK).
aneko: JAPAN DISPLAY '92, PP.591, (1992)) has been proposed. In this method, a pixel is divided into two, and in each pixel, there are two kinds of directions that are tilted by the electric field of liquid crystal molecules located on the midplane, thereby compensating for the difference in birefringence depending on the viewing angle and expanding the viewing angle. Is intended.

However, in such a method, since the alignment region of one pixel has to be divided into two, there is a drawback that the exposure process and the rubbing process process increase and the manufacturing process becomes complicated. Therefore, as a further advanced technology, an epoch-making method for expanding the viewing angle at the same time without rubbing has been proposed (Y.Toko, T.Sugiyama, K.
Katoh, Y.Iimura, S.Kobayashi: SID 93 DIGEST, PP.622, (1
993)). This is called random alignment TN. In this method, the liquid crystal material is injected at a temperature above the nematic-isotropic phase transition temperature without performing rubbing treatment between the substrates coated with the polyimide alignment film, and then the liquid crystal molecules are randomly dispersed. By orienting, a large number of regions (domains) having different orientation directions of liquid crystal molecules are formed, thereby expanding the viewing angle.

A display system of a random alignment TN type liquid crystal display panel which does not require the rubbing treatment will be described below with reference to the drawings. FIG. 4 is a perspective view schematically showing the alignment of liquid crystal molecules in a random alignment TN type liquid crystal display panel when no electric field is applied. As shown in this figure, a chiral nematic having a twist angle of about 90 degrees is spontaneously provided between an upper substrate 501 and a lower substrate 502, which face each other with a constant gap and have a polyimide alignment film formed on the surface thereof. When the liquid crystal is sealed at a temperature above the nematic-isotropic phase transition temperature and then cooled to room temperature, the liquid crystal molecules 504 at the substrate interface have random orientations that can be taken between the domains on the substrate at exactly the same probability. A large number of liquid crystal domains 506 having a structure in which the liquid crystal molecules of 1 and the liquid crystal molecules of the lower substrate are twisted by 90 degrees are generated.

In this panel, the liquid crystal molecules 505 located in the midplane are initially oriented substantially horizontally,
When a voltage is applied, the dielectric free energy becomes smaller, that is, the dielectric anisotropy is inclined such that> 0, and at a high applied voltage, it stands in the vertical direction. Since the liquid crystal molecule 505 of the midplane is a liquid crystal molecule located at the center in the thickness direction of the upper and lower substrates, in the case of a 90 degree twist angle, it is just the full twist angle, that is, the liquid crystal molecule 503 of the upper substrate and the liquid crystal molecule 504 of the lower substrate. It exists at a position twisted by 45 degrees, which is ½ of the angle formed by. Since the tilt direction due to the voltage application of the liquid crystal molecules 505 of the midplane determines the viewing angle direction, the viewing angle direction is constant within one liquid crystal domain, but these liquid crystal domains having a random alignment direction form one pixel. The presence of a sufficient number in the matrix makes them macroscopically averaged so that the transmittance intensities in various observation directions become almost symmetrical and the viewing angle dependence disappears. However, as can be seen from the above description, if the number of liquid crystal domains in one pixel is not sufficiently large, or if the orientation of each liquid crystal domain is not completely random, compensation cannot be made completely, and the viewing angle dependence remains. Will be done.

[0013]

DISCLOSURE OF THE INVENTION Random orientation T
The wide viewing angle system using the N-type liquid crystal display panel has the following problems.

That is, in the random alignment type liquid crystal display panel, as described above, the liquid crystal material must be injected at a temperature above the nematic-isotropic phase transition temperature in order to avoid flow alignment defects due to liquid crystal flow at the time of injecting all liquid crystals. Manufacturing equipment is required. Further, in the commonly used vacuum liquid crystal injection method, the liquid crystal material is exposed to a vacuum at a high temperature, and the low boiling point material in the liquid crystal material is dissipated, so that the display quality and reliability are degraded. is there. Also, in a liquid crystal display panel for a small image display device or a small information terminal, the RGB electrode pitch is, for example, 50 μm.
Although there are some m or less, it is difficult to make a large number of even smaller liquid crystal domains stably exist in such a minute pixel. In particular, linear alignment defects (disclination lines) that occur when a voltage is applied are energetically unstable, and therefore adjacent liquid crystal domains tend to coalesce to grow into larger liquid crystal domains. . Further, when the size of the liquid crystal domain is not sufficiently small, the difference in the transmittance intensity between the liquid crystal domains in the oblique direction is observed as a feeling of roughness, and there is a problem that the display quality is significantly impaired. Further, the disclination line generated when an electric field is applied is hard to disappear even when a high voltage is applied when black is displayed, and the light leakage due to this causes a reduction in contrast.

The present invention has been made in view of the above problems. It is possible to inject liquid crystal near room temperature, to enlarge the viewing angle without performing rubbing treatment, and within a minute pixel. A finer liquid crystal domain exists more stably than that, and alignment defects disappear at high applied voltage.
An object of the present invention is to provide a liquid crystal display panel having excellent display quality and a manufacturing method thereof.

[0016]

A liquid crystal display panel according to the present invention includes two transparent substrates with transparent electrodes, which are arranged at a predetermined interval so that their electrode-arranged surfaces face each other, and the above-mentioned two substrates. A first polymer film formed on each electrode disposition surface of the transparent substrate with a transparent electrode, and a plurality of films formed on the surface of the first polymer film so as to extend substantially perpendicularly to the surface. And a plurality of circles made of a chiral nematic liquid crystal material having a positive dielectric anisotropy surrounded by the first polymer film and the plurality of second polymer films. A minute unit liquid crystal cell in the form of a plate; and a polarizing plate disposed on the outer surface of at least one of the two transparent substrates with transparent electrodes, wherein the plurality of minute unit liquid crystal cells are the first Liquid crystal molecules on the surface of the polymer film are aligned in a certain direction The first and the minute unit liquid crystal cell composed of Te,
The second minute unit liquid crystal cell in which the liquid crystal molecules existing on the same plane are arranged in line symmetry or point symmetry is mixed.

In the above arrangement, it is preferable that the average diameter of the minute unit liquid crystal cells is equal to or less than the pixel pitch. In the above structure, the ratio d / P between the spontaneous pitch (P) of the chiral nematic liquid crystal material and the thickness (d) of the minute unit liquid crystal cell is preferably 0.25.

In the above structure, it is preferable that polarizing plates are disposed on both outer surfaces of the two transparent substrates with transparent electrodes, and the crossing angle of these two polarizing plates is 90 degrees. Next, in the method for manufacturing a liquid crystal display panel according to the present invention, two transparent substrates with transparent electrodes, the surfaces of which electrodes are provided are coated with a first polymer film, are prepared, and these two transparent substrates with transparent electrodes are prepared. After forming a blank cell by adhering the substrates to each other with a sealing material so that the polymer films face each other with a predetermined gap therebetween, a chiral nematic liquid crystal material containing a predetermined amount of a chiral agent and an ultraviolet curable resin monomer are added. Injecting a mixture into the gap of the empty cell, then irradiating the mixture with ultraviolet light to cure the ultraviolet curable resin monomer,
A second polymer film is formed on the surface of the first polymer film so as to stand upright on the surface, and thereafter, the electrode disposition surface of at least one of the two transparent substrates with transparent electrodes is A polarizing plate is arranged on the substrate surface on the different side.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In a liquid crystal display panel of the present invention, two transparent substrates with transparent electrodes, which are arranged at a predetermined interval so that their electrode-disposed surfaces face each other, and the two transparent substrates described above. A first polymer film formed on each electrode arrangement surface of the transparent substrate with electrodes, and a plurality of first polymer films formed on the surface of the first polymer film so as to extend substantially perpendicular to the surface. A plurality of disc-shaped members made of a chiral nematic liquid crystal material having a positive dielectric anisotropy surrounded by the polymer film 2 and the first polymer film and the plurality of second polymer films. A minute unit liquid crystal cell and a polarizing plate arranged on the outer surface of at least one of the two transparent substrates with transparent electrodes, wherein the plurality of minute unit liquid crystal cells are
The first minute unit liquid crystal cell in which liquid crystal molecules existing on the surface of the first polymer film are arranged in a certain direction, and the liquid crystal molecules existing on the same plane are arranged in line symmetry or point symmetry. Since the second minute unit liquid crystal cells are mixed, each of the plurality of minute unit liquid crystal cells is surrounded and divided by the second polymer film, so that a display without roughness can be obtained. The disclination line does not grow significantly. Also, the first in the cell
Since there are a plurality of first cells in which liquid crystal molecules existing on the polymer film surface (the surface where the electrodes of the substrate are arranged) are arranged in a certain direction, the macroscopic viewing angle direction is averaged and the viewing angle direction dependence is obtained. In the second cell in which liquid crystal molecules existing in the same plane in the cell are arranged in line symmetry or point symmetry, the viewing angle compensation is completed in the cell, and therefore, an extremely wide viewing angle is displayed. be able to. Further, when the ions are generated in the liquid crystal cell, the first polymer film prevents the ions from reaching the pixel electrode of the substrate, so that it is possible to prevent the deterioration of the display quality due to the decrease of the applied voltage. .

As a preferred example of the above structure, when the average diameter of the minute unit liquid crystal cells is equal to or less than the pixel pitch, it is possible to completely prevent the liquid crystal molecules from being biased in the horizontal direction, and thus display with a wider viewing angle is performed. You can

As a preferred example of the above construction, when the ratio d / P between the spontaneous pitch (P) of the chiral nematic liquid crystal material and the thickness (d) of the minute unit liquid crystal cell is 0.25, the brightness of the panel is reduced. It can be high and have a good tint.

As a preferred example of the above-mentioned constitution, when the polarizing plates are arranged on both outer surfaces of the two transparent substrates with transparent electrodes, and the crossing angle of these two polarizing plates is 90 degrees, there is no electric field. It is possible to perform high-contrast display in which white sometimes occurs and black when an electric field is applied.

Next, in the method of manufacturing a liquid crystal display panel according to the present invention, two transparent substrates with transparent electrodes, the surfaces of which electrodes are provided are covered with a first polymer film, are prepared. A transparent substrate with electrodes is adhered with a sealing material so that the polymer films face each other with a predetermined gap therebetween to form an empty cell, and then a chiral nematic liquid crystal material and an ultraviolet curable resin to which a predetermined amount of a chiral agent is added. Injecting a mixture with a monomer into the gap of the empty cell, then irradiating the mixture with ultraviolet rays to cure the ultraviolet curable resin monomer, and standing on the surface of the first polymer film. The second polymer film is formed, and thereafter, the polarizing plate is arranged on the substrate surface of at least one of the two transparent substrates with transparent electrodes, which is different from the electrode arrangement surface. , The first and The liquid crystal display panel having a plurality of minute unit liquid crystal cell surrounded formed by two of the polymer film can be easily prepared.

The operation of the liquid crystal display panel of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing the configuration of an example of a liquid crystal display panel according to the present invention. In the figure, 101 and 102 are an upper glass substrate and a lower glass substrate, and a polarizing plate 10 is provided on the upper surface of the upper glass substrate 101.
7 is provided, and the transparent electrode 103 is provided on the lower surface. The transparent electrode 10 is formed on the upper surface of the lower glass substrate 102.
4 is provided, and a polarizing plate 108 is provided on the lower surface. All liquid crystal domains (unit liquid crystal cells) made of the chiral nematic liquid crystal 109 have transparent electrodes 103 and 104.
The liquid crystal domains (unit liquid crystal cells) sandwiched by the unrubbed first polymer film 110 formed on the respective surfaces of the transparent electrodes 103, 104
It is surrounded and divided by the second polymer film 111 formed so as to extend in a substantially vertical direction between the unrubbed first polymer film 110 formed on each surface of the. Further, in the figure, 105 is a sealing material, and 106 is a spacer. Here, the second polymer film 111 for forming the unit liquid crystal cell does not necessarily have to be connected between the transparent electrodes 103 and 104, and the central portion may be divided. Further, the liquid crystal domain (unit liquid crystal cell) and the second polymer film 111 are formed by irradiating a mixture of a nematic liquid crystal material (chiral nematic liquid crystal 109) and an ultraviolet curable resin monomer with ultraviolet rays to perform optical phase separation. To be done.

In such a liquid crystal display panel, the transparent electrode 10
When a voltage is applied between 3 and 104, the liquid crystal molecules of the chiral nematic liquid crystal 109 gradually incline from the horizontal due to the positive dielectric anisotropy, but unlike the random alignment TN, each liquid crystal domain (unit Since the liquid crystal cell) is surrounded and divided by the second polymer film 111, the disclination line does not grow significantly.

The second polymer film 111 that surrounds and divides each liquid crystal domain (unit liquid crystal cell) irradiates the mixture of the nematic liquid crystal material and the ultraviolet curable resin monomer with ultraviolet rays as described above to perform optical phase separation. Since it is formed by doing so, it is possible to make the domain diameter fine enough, and it is possible to obtain a display without a feeling of roughness. Further, since the polymer obtained by such optical phase separation has almost no birefringence, when it is sandwiched by two polarizing plates (107, 108) having a crossing angle of 90 degrees, the polymer wall The light passing through (the second polymer film 111) is blocked,
The contrast of the liquid crystal display panel does not deteriorate. The liquid crystal domain (unit liquid crystal cell) divided by the second polymer film 111 can compensate the viewing angle as in the case of the random alignment TN. There are two compensation mechanisms.

That is, the first viewing angle compensation mechanism is the same as that of the random alignment TN, and the liquid crystal molecules at the interface of the substrate are randomly oriented with equal probability among the liquid crystal domains on the substrate. In one liquid crystal domain, the liquid crystal molecules of the upper substrate and the liquid crystal molecules of the lower substrate have a twisted structure depending on the chiral addition amount (typically 90
Angle), the viewing angle direction is constant within one liquid crystal domain, but because there are a sufficient number of these liquid crystal domains with random orientations in one pixel, they are macroscopically averaged and The transmittance intensity in the observing direction becomes almost symmetrical, and the viewing angle dependence disappears.

The second viewing angle compensating mechanism is different from the random alignment TN in that each liquid crystal molecule in one liquid crystal domain is arranged in point symmetry or line symmetry so that compensation can be completed in one liquid crystal domain. is there. However, the liquid crystal molecules of the upper substrate and the liquid crystal molecules of the lower substrate have a twisted structure (typically 90 degrees) depending on the chiral addition amount, as in the first viewing angle compensation mechanism. With this mechanism, viewing angle compensation can be performed within one liquid crystal domain, and therefore it is not necessary for a plurality of liquid crystal domains to exist in one pixel.

FIG. 2 is a diagram for explaining the first viewing angle compensation mechanism, in which the liquid crystal molecules 204 and 205 existing on the surfaces of the upper and lower substrates 201 and 202 are aligned in the liquid crystal domain. However, the liquid crystal domains are random. In this mechanism, since the viewing angle direction is constant in one liquid crystal domain, it is necessary that a sufficient number of liquid crystal domains be present in one pixel to compensate the viewing angle.

FIG. 3 is a diagram for explaining the second viewing angle compensation mechanism. In FIG. 3A, the liquid crystal molecules 302 and 303 existing on the surfaces of the upper and lower substrates and the liquid crystal molecule 305 of the midplane have singular points. They are arranged in point symmetry in the center. In addition, the liquid crystal molecules 302 existing on the surface of the upper substrate and the liquid crystal molecules 303 existing on the surface of the lower substrate have a twisted structure (typically 90 degrees) according to the chiral addition amount, and the liquid crystal molecules 305 of the midplane. Exists at a position twisted by 1/2 of the total twist angle.

A liquid crystal display panel of the present invention having a structure in which each liquid crystal domain (unit liquid crystal cell) is surrounded and divided by a polymer film is actually irradiated with ultraviolet rays on a mixture of a nematic liquid crystal material and an ultraviolet curable resin monomer. It was found that the structure by the first viewing angle compensation mechanism and the structure by the second viewing angle compensation mechanism coexist when they are formed by optical phase separation.

The second polymer film 111 can be easily formed by irradiating a mixture of a nematic liquid crystal material and an ultraviolet curable resin monomer with ultraviolet rays to cause optical phase separation. Even when a fluorine-based liquid crystal material having light resistance to ultraviolet rays is used, ionic species are generated in the liquid crystal domain due to the decomposition of liquid crystal molecules and the decomposition of the polymer due to ultraviolet rays. TFT (thin
film toransistors) Compose LCD panel and TFT
When driving, it is necessary to retain the charge of the pixel within one frame (usually 1/30 second), but the generation of such ions causes the ions to move in the liquid crystal to neutralize the charge of the pixel,
Causing the phenomenon of reducing the applied voltage,
This will significantly impair the display quality. However, in the liquid crystal display panel according to the present invention, the first polymer film 110 prevents the ions from reaching the pixel electrode on the electrode substrate, and thus can have a high voltage holding property.
Another function of the first polymer film 110 is that the first polymer film 110 is formed as a single film on surfaces having different properties, such as an electrode portion and a non-electrode portion, so that the substrate surface In order to make the liquid crystal alignment state (especially pretilt) uniform.

The first polymer film 110 can be easily formed by a spinner coating method or a printing method which has been put into practical use.

[0034]

EXAMPLES The present invention will be described below with reference to examples and comparative examples. (Experimental Example 1) After cleaning a pair of transparent transparent glass substrates provided with transparent electrodes made of an indium / tin oxide film, and drying at 110 ° C. for 30 minutes to form a polymer film on the electrode mounting surface of the substrate, A 5 μm diameter plastic spacer 106 (Micropearl: Sekisui Fine Co., Ltd.) was used to bond the thermosetting sealant (StructBond: Mitsui Toatsu Chemical Co., Ltd.) with a liquid crystal injection port provided, and bonded together. The sealing material was completely cured by heating at ℃ for 4 hours to obtain an empty cell. Here, as the polymer film, soluble polyimide resin film AL-5417 (Nippon Synthetic Rubber Co., Ltd.), polyimide resin film RN-747 (Nissan Chemical Co., Ltd.), UV curing resin PN3
93 (Merck) and polyurethane MS5510
(Mitsubishi Heavy Industries, Ltd.) was used to prepare a sample for each polymer film. In addition, the film formation conditions for the polymer film are 2000 rpm and 6
Spinner was applied under the condition of 0 seconds, and was dried at 150 ° C. for 1 hour, at 200 ° C. for 1 hour,
About 40 mW / cm2 of ultraviolet light at 40 ° C
For 0 second irradiation, curing treatment was performed at 150 ° C. for 1 hour.

As a liquid crystal material, a chiral material S-811
Fluorine nematic liquid crystal ZLI-4792 with refractive index anisotropy of 0.09 (Merck Co., Ltd.) whose concentration was adjusted so that the spontaneous twist pitch (P) was d / P = 0.25 with respect to the cell gap (d). ) 8.20 grams, UV
1.80 grams of polymerizable material PN393 (Merck) was prepared (the ratio of liquid crystal material to polymer-liquid crystal mixed material was 8).
2% by weight) and sufficiently stirred at 40 ° C. to prepare a uniform polymer-liquid crystal mixed solution.

This homogeneous mixed solution was injected into the empty cell previously heated on a hot plate at 40 ° C. from the liquid crystal injection port, the injection port was sealed, and then 40 mW / cm at 40 ° C.
A liquid crystal display panel was produced by irradiating with ultraviolet rays of 2 for 200 seconds. As a result of observing this liquid crystal display panel with a polarization microscope in a crossed Nicols state, the diameter 10
An approximately circular liquid crystal domain (unit liquid crystal cell) having a size of ˜30 μm was formed. It was observed that in the liquid crystal domain, there was one alignment defect in the center, and four black bands were formed radially around the alignment defect. Then, when the liquid crystal panel was fixed and the polarizer and the analyzer were rotated, the four black bands were rotated in the same direction as the polarizer by the same angle. Further, each liquid crystal domain is completely partitioned by a polymer wall having a thickness of 2 μm or less, but since the polymer wall itself does not transmit light, a black frame is formed.

Subsequently, when a square wave having various voltages of 30 Hz was applied to this panel to observe the liquid crystal domain,
At around 1.5V, the disclination line starts to ring along the polymer wall on the liquid crystal domain side,
When the voltage was gradually increased, the diameter of the ring gradually decreased and disappeared at about 4V.

Next, a polarizing plate was attached to the outside of the liquid crystal display panel so that the polarization axes crossed 90 degrees, placed on a light box for photography, and 0 to 16 V, 30 Hz at room temperature.
A square wave of various voltages was applied to observe the lighting state of the liquid crystal panel. The liquid crystal panel started to light at about 1V, and almost perfect black display was obtained at 5V. Also, 30 on this panel
When observed from various directions while applying a square wave of 5 Hz at 5 Hz, a good black display was obtained without any feeling of roughness in any direction.

Next, the contrast ratio on the front of this panel = (panel brightness when no voltage is applied) / (30 Hz, 5 V
When the panel brightness at the time of application was measured, a value of 100 or more was obtained. In addition, as a result of examining the angle range giving a contrast ratio of 5 or more in the vertical direction and the horizontal direction,
It was over 70 degrees. Furthermore, when the panel brightness-voltage characteristics were measured in various observation directions, the panel brightness all decreased monotonically with respect to the applied voltage. This means that this panel exhibits excellent display characteristics without gradation inversion even in full-color display.

Further, this liquid crystal panel was left to stand in a thermostatic chamber at 40 ° C., and a 5 V square wave AC pulse having a width of 60 μs was applied for 3 times.
As a result of applying voltage at 3 ms intervals and measuring voltage holding characteristics in TFT drive (Shimazaki, Mizushima, Minezaki, Yano: Proceedings of 14th Liquid Crystal Conference, 2B110), soluble polyimide resin film AL-5417 (Nippon Gosei Gomu Co., Ltd.) 8 panels using
5%, polyimide resin film RN-747 (Nissan Chemical Co., Ltd.)
Is 90%, UV curing resin PN393
The panel using (Merck) was 40%, and the panel using polyurethane MS5510 (Mitsubishi Heavy Industries) was 15%.

(Example 2) As the liquid crystal material, the addition amount of the chiral material CN (manufactured by Chisso Petrochemical) was changed variously,
The spontaneous twist pitch P with respect to the cell gap d is d /
Fluorine-based nematic liquid crystal ZLI-47 having a refractive index anisotropy of 0.09 prepared so that P = 0.05 to 0.5.
92 (Merck) and UV-polymerizable material PN393 (Merck) were prepared so that the ratio of the liquid crystal material to the polymer-liquid crystal mixture material would be 82% by weight, and these were mixed and sufficiently stirred to homogeneity. After preparing the mixed solution, a liquid crystal display panel was produced in the same manner as in Example 1.

A polarizing plate is attached to the outside of the liquid crystal display panel thus completed so that the polarization axes intersect each other at 90 degrees, and
A square wave of Hz was applied to observe the panel brightness at various voltages.

As a result, in the panel where d / P is smaller than 0.25 and the panel where d / P is larger than 0.25, the transmittance of the panel, that is, the panel brightness is darker than when d / P = 0.25, and In the panel having d / P of more than 0.25, not only dark but also intense green-yellow coloring was observed, and the display quality was not good. The panel with d / P of about 0.25 was excellent in the brightness and color of the panel.

Although the unit liquid crystal cell surrounded by the polymer wall is formed by optical phase separation in the above embodiment, the polymer wall is formed by using, for example, photolithography in the present invention. However, the same result can be obtained.

In the above-mentioned embodiment, the polarizing plate is an example in which the liquid crystal panel is sandwiched by two polarizing plates whose polarization axes are orthogonal to each other for the purpose of enhancing the contrast in the normally white mode, but no voltage is applied. In order to improve the transmittance at the time or to adjust the hue, the crossing angle of the polarization axes may be slightly shifted from 90 degrees, or the polarization axes may be arranged in parallel for use in the normally black mode. . Further, in the case of using the reflective type, one polarizing plate may be arranged on the front substrate to display.

[0046]

As described above, according to the present invention, it is possible to obtain a high-quality display having a high contrast and no feeling of graininess and gradation inversion, and further, a liquid crystal display panel capable of displaying a wide viewing angle. Can be obtained. In addition, at the time of manufacturing, it is not necessary to perform rubbing treatment or heating at a high temperature above the nematic-isotropic phase transition point at the time of injecting liquid crystal, and a polymer film is formed on the electrode-arranged surface of the transparent substrate with a transparent electrode. After the formation, a mixture of a nematic liquid crystal material and an ultraviolet curable resin monomer is injected between two transparent substrates with transparent electrodes near room temperature, and then the mixture is irradiated with ultraviolet rays to perform optical phase separation. Therefore, there is also an effect that the manufacturing work is simple.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of an example of a liquid crystal display panel according to an embodiment of the present invention.

FIG. 2 illustrates a liquid crystal display panel 90 according to an embodiment of the present invention.
It is a conceptual diagram which shows the orientation state of the 1st liquid crystal molecule of the unit liquid crystal cell which has a degree twist structure.

FIG. 3 illustrates a liquid crystal display panel 90 according to an embodiment of the present invention.
It is a conceptual diagram which shows the orientation state of the 2nd liquid crystal molecule of the unit liquid crystal cell which has a twist structure.

FIG. 4 is a conceptual diagram showing an alignment state of liquid crystal molecules in each domain of a conventional random alignment liquid crystal display panel.

[Explanation of symbols]

101 Upper Glass Substrate 102 Lower Glass Substrate 103, 104 Transparent Electrode 105 Sealing Material 106 Spacer 107, 108 Polarizing Plate 109 Chiral Nematic Liquid Crystal 110 First Polymer 111 Second Polymer 201, 501 Upper Substrate 202, 502 Lower Substrate 203 , 306 Polymer wall 204, 205, 302, 303, 307, 308, 5
03,504 Liquid crystal molecule 206,304,309 Midplane 301 Polymer wall 305,310,505 Liquid crystal molecule on midplane 506 Liquid crystal domain

Claims (5)

[Claims] 1. Two transparent substrates with transparent electrodes, which are arranged so as to face each other at a predetermined interval, and the respective electrode mounting surfaces of the two transparent substrates with transparent electrodes. A first polymer film formed on the first polymer film, a plurality of second polymer films formed on the surface of the first polymer film so as to extend substantially perpendicularly to the surface, and the first polymer film. Surrounded by a polymer membrane and the plurality of second polymer membranes,
A plurality of disk-shaped minute unit liquid crystal cells made of a chiral nematic liquid crystal material having a positive dielectric anisotropy;
A polarizing plate disposed on the outer surface of at least one of the transparent substrates with transparent electrodes, wherein the plurality of minute unit liquid crystal cells have liquid crystal molecules present on the surface of the first polymer film. Liquid crystal display in which first fine unit liquid crystal cells arranged in a fixed direction and second fine unit liquid crystal cells in which liquid crystal molecules existing on the same plane are arranged in line symmetry or point symmetry are mixed. panel. 2. The liquid crystal display panel according to claim 1, wherein the average diameter of the minute unit liquid crystal cells is not more than the pixel pitch. 3. The liquid crystal display panel according to claim 1, wherein a ratio d / P between the spontaneous pitch (P) of the chiral nematic liquid crystal material and the thickness (d) of the minute unit liquid crystal cell is 0.25. 4. The liquid crystal display panel according to claim 1, wherein polarizing plates are provided on the outer surfaces of both of the two transparent substrates with transparent electrodes, and the crossing angle of these two polarizing plates is 90 degrees. . 5. Two transparent substrates with transparent electrodes, the surfaces of which electrodes are provided are covered with a first polymer film, are prepared, and these two transparent substrates with transparent electrodes are mutually arranged such that the polymer films have a predetermined shape. After forming a blank cell by adhering with a sealing material so as to face each other with a gap, a mixture of a chiral nematic liquid crystal material containing a predetermined amount of a chiral agent and an ultraviolet curable resin monomer is injected into the gap of the blank cell. Then, the mixture is irradiated with ultraviolet rays to cure the ultraviolet curable resin monomer, and a second polymer film standing on the surface of the first polymer film is formed on the surface of the first polymer film. A method for manufacturing a liquid crystal display panel, wherein a polarizing plate is provided on the surface of at least one of the two transparent substrates with transparent electrodes, which is different from the surface on which the electrodes are provided.