JPH06317808A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE:To prevent an active element from being deteriorated even if the element is irradiated with light when produced. CONSTITUTION:When a photopolymerizable resin in a mixture injected into a cell is cured, TFT 2 is not irradiated with light since the TFT 2 is covered with a photomask 5, a light-shielding layer or another light-shielding layer. Meanwhile, an aligning marker is formed on the photomask 5 and a substrate, and the photomask and substrate 5 are aligned based on the marker. Especially, when one of the markers is drawn out of a part of the other, both markers are superimposed on each other without any clearance in between, and the photomask 5 is precisely aligned with the substrate.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can be applied to, for example, flat displays (personal computers, word processors, amusement devices, televisions) utilizing a wide viewing angle, display plates utilizing shutter effect, windows, doors, walls, etc. The present invention relates to a liquid crystal display element in which picture elements are arranged in a matrix and a method for manufacturing the same. More specifically, it has a display medium in which a liquid crystal region mainly made of a liquid crystal material is surrounded by polymer walls, and TN, STN,
The present invention relates to a liquid crystal display element driven by a conventional mode such as ECB or FLC, or a mode in which a liquid crystal region having a radial liquid crystal domain is oriented axially symmetrically within a pixel, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Liquid crystal display devices are available in various display modes. For example, as a liquid crystal display device utilizing the electro-optical effect, a TN type or STN type using nematic liquid crystal has been put into practical use. A liquid crystal display device using a ferroelectric liquid crystal has also been proposed. These require polarizing plates and alignment treatments.

Further, there is a liquid crystal display element which utilizes a light scattering of liquid crystal without using a polarizing plate and which utilizes a dynamic scattering (DS) effect or a phase transition (PC) effect.

Recently, there has been proposed a method of electrically controlling the transparent state or the clouded state by utilizing the birefringence of liquid crystals, as a means which does not require a polarizing plate and does not require an alignment treatment. In this method, basically, the ordinary refractive index of the liquid crystal molecules and the refractive index of the support medium surrounding the liquid crystal molecules are matched, and a transparent state is displayed when the alignment of the liquid crystal molecules is aligned by voltage application, When the orientation of the liquid crystal molecules is disturbed by the application of no voltage, a white turbid state in which light is scattered is displayed.

As a specific example of the proposed method, a method of encapsulating a liquid crystal in a polymer capsule (Japanese Patent Publication No. 58-501).
631), or a method of mixing liquid crystal and a photo-curable or thermosetting resin and curing the resin to cause the liquid crystal to be broken out to form liquid crystal droplets in the resin (Japanese Patent Publication No. 61-50212).
8), or a method of forming a phase-separated state of a liquid crystal and a polymer by removing the solvent from a mixture of a mixture of the polymer and the liquid crystal and a solvent which dissolves the mixture (JP-A-59-226322). Are known.

However, in the case of these proposed methods, there are problems that it is difficult to sufficiently control the arrangement and size of the liquid crystal portion or the liquid crystal droplets, and it is difficult to perform the alignment treatment.

In order to solve these problems, the present inventors have proposed the following liquid crystal display device. In this liquid crystal display element, a mixture of a liquid crystal material, a photocurable resin and a photoinitiator is injected between two substrates arranged opposite to each other, and thereafter,
By irradiating with ultraviolet light over the photomask so that the picture element portion becomes the light-shielding portion, the liquid crystal area is gathered in the picture element portion, and the display medium in which the polymer is gathered in the portion other than the picture element is provided. .

Such a liquid crystal display device uses a nematic liquid crystal, and when the liquid crystal domain formed in the liquid crystal region is in a radial or random state within the picture element, the viewing angle characteristic is remarkably higher than that of the TN cell. Be improved. Further, when a ferroelectric liquid crystal material is used, impact resistance is remarkably improved due to the reinforcing effect of the polymer walls reaching the inner surfaces of both substrates, and the liquid crystal region is formed in the pixel portion, so that the contrast characteristic It has the characteristic of little deterioration.

[0009]

However, in the above liquid crystal display device, when the liquid crystal display device is manufactured on a substrate having an active device such as a TFT, the photomask is covered so as to cover only the pixel portion, and ultraviolet irradiation is performed. Then, there is a problem that the active element is directly irradiated with ultraviolet rays to cause deterioration of the active element.

The present invention has been made in order to solve the problems of the prior art, and a liquid crystal display device and its manufacturing method capable of preventing the active device from deteriorating even if light is irradiated during the manufacture of the device. The purpose is to provide.

[0011]

According to the method of manufacturing a liquid crystal display device of the present invention, two substrates are arranged to face each other with a display medium having a liquid crystal region surrounded by a polymer wall interposed therebetween. In the method of manufacturing a liquid crystal display element in which the picture elements for performing the above are arranged in a matrix, and the active elements are provided on one substrate, the step of arranging the two substrates in opposition and Since the method includes a step of injecting a mixture containing at least a liquid crystal material and a photopolymerizable resin between the substrates, and a step of irradiating the mixture with light as the non-light irradiation region of the picture element and the active element. The above object is achieved.

A photomask can be used as a means for forming the non-light irradiation area. In this case, a photomask is provided on the other substrate side, and light is emitted from the other substrate side. As a means for forming the non-light-irradiated region, a light-shielding layer provided on one or the other substrate for the active element and a photomask provided outside the substrate having the light-shielding layer for the picture element are used. be able to. In this case, light is emitted from the photomask side.

Further, when a black mask having a light-transmitting portion of a picture element portion is formed as a light-shielding layer, a photomask is provided so as to cover all or part of the light-transmitting portion of the black mask, and the black mask is used. It can be performed as a structure having a light transmitting portion larger than the photomask and / or a structure having a light transmitting hole in the light shielding portion of the black mask.

When a black mask having a light-transmitting portion of a picture element is formed as the light-shielding layer, another black-light shielding layer having a shape corresponding to the light-transmitting portion of the black mask is provided on the black mask. This can be performed by forming a material containing a compound that absorbs light on a substrate opposite to the substrate and irradiating light from the side of the other light shielding layer.

A marker for alignment is formed on the photomask and the substrate on which the photomask is provided, the photomask and the substrate are aligned based on the marker, and then light is irradiated. You can also do it.
In this case, one of the markers formed on the photomask and the substrate is formed by extracting a part of the other, and by superimposing the markers so that no gap exists between the markers, the photomask and the substrate are separated. You may align.

In the liquid crystal display device of the present invention, two substrates are arranged facing each other with a display medium having a liquid crystal region surrounded by a polymer wall sandwiched therebetween, and picture elements for display are arranged in a matrix. In a liquid crystal display element in which an active element is provided on one substrate while being provided, the substrate on which the active element is formed has a structure in which a light shielding layer is provided between the base substrate and the active element. Therefore, the above object is achieved thereby.

[0017]

In the present invention, when the photopolymerizable resin in the mixture injected into the cell is cured, the active element is covered with a photomask, a light shielding layer, or another light shielding layer. The active element is not irradiated with light.

Further, when a marker for alignment is formed on the photomask and the substrate, the photomask and the substrate can be easily aligned on the basis of the marker. Especially, when one of the markers is formed by extracting a part of the other, by overlapping both markers so that there is no gap between them, the photomask and the substrate can be accurately aligned. To be done.

[0019]

EXAMPLES Examples of the present invention will be described below.

Example 1 First, on a glass substrate having a thickness of 1.1 mm, transparent ITO (a mixture of indium oxide and tin oxide) having a thickness of 500 Å was formed as a counter electrode, and a transparent ITO film for 4 inches was formed. Obtain the counter substrate. Further, as shown in FIG. 1, a source bus line 3 as a signal line, a gate bus line 4 as a scanning line, a pixel electrode 1, and these source bus lines 3 are provided on a glass substrate having a predetermined thickness. Then, a thin film transistor (TFT) 2 functioning as an active element connected to the gate bus line 4 and the pixel electrode 1 is formed to obtain a 4-inch TFT substrate. Note that a 4-inch counter substrate and a TFT substrate which are manufactured in advance may be used.

Next, the counter substrate and the TFT substrate are made to face each other without forming an alignment film, and the two substrates are placed between the two substrates.
A cell having a constant cell thickness with a spacer of 5 μm interposed was produced. In this case, since there is no light-shielding layer such as a black mask in the cell, the portion of the picture element electrode 1 becomes a picture element.

Next, as shown in FIG. 1, a photomask 5 having a light transmitting hole 5b at approximately the center of a light shielding portion 5a (shown by hatching) which shields at least the pixel electrode 1 and the TFT 2 is used. The photomask 5 is placed on the counter substrate side of the cell. At this time, the photomask 5 is connected to the pixel electrodes 1 and T
Set so as to cover FT2. The photomask material may be any material that can block ultraviolet rays, and metals such as molybdenum and aluminum are suitable. The same applies to each of the following examples.

Next, 0.1 g of R-684 (manufactured by Nippon Kayaku Co., Ltd.), 0.05 g of styrene, 0.75 g of isobornyl methacrylate, 0.10 g of perfluorooctyl methacrylate and Merck. Chiral agent S-81 manufactured by
4 g of liquid crystal material ZLI-4792 to which 0.3% of 1 was added
And 0.0025 g of a photopolymerization initiator Irugacure651
(Manufactured by Ciba-Geigy) was mixed in advance and the mixture was vacuum-injected into the cell at 40 ° C.

Next, a cell was set at a position of 10 mW / cm ² under a high-pressure mercury lamp capable of obtaining parallel lines, and while keeping the mixture at 40 ° C., ultraviolet light was passed through the photomask 5 to the cell, Irradiation is performed for 20 cycles, with 1 second irradiation and 30 seconds non-irradiation as one cycle. Then, irradiation was continuously performed for 10 minutes, the photomask 5 was removed, and ultraviolet rays were continuously irradiated for 10 minutes to cure the resin in the mixture. As a result, the display medium in which the liquid crystal region in which the liquid crystal domains are radially arranged is surrounded by the polymer wall is formed in the cell.

Next, a liquid crystal display device was manufactured by laminating two polarizing plates perpendicular to each other on both sides of the cell thus manufactured.

2 (a), (b), (c), (d),
(E) shows the change in the transmittance (vertical axis) with respect to the applied voltage (horizontal axis) in the electro-optical characteristics of the manufactured liquid crystal display element. FIG. 2F shows the direction in which the electro-optical characteristics are measured. 2 (a) is the characteristic measured from the vertical direction a of the cell, and FIG. 2 (b) is the direction tilted by 40 ° from the vertical direction a of the cell to the b direction, which is the same as the polarization axis of the polarizing plate on the upper surface. It is the characteristic when the cell is measured from the direction of 45 °. 2 (c), (d), and (e) are the directions in which the vertical direction a of the cell is tilted by 40 ° in the c direction, the d direction, and the e direction, respectively. It is the characteristic when the cell is measured from the direction of 45 °. Note that b
The direction, the c direction, the d direction, and the e direction are offset from each other by 90 °. Further, the polarization axis is oriented in the direction perpendicular to the polarizing plate.

As can be seen from FIG. 2, the liquid crystal display element of this embodiment does not cause a black and white reversal phenomenon as compared with the viewing angle characteristics of the conventional TN mode, and the amount of change in the applied voltage-transmittance curve. Has become less.

(Comparative Example 1) Next, a liquid crystal display device according to a comparative example was manufactured.

First, a TFT cell similar to that of Example 1 was obtained by vacuum injection of the same mixture as that of Example 1.

Next, as shown in FIG. 3, a photomask 25 having a structure in which a light-transmitting hole 25b is provided at substantially the center of a light-shielding portion 25a (shown by hatching) that covers only the pixel electrode 1 is used. The cell was covered so as to cover only the pixel electrode 1, and ultraviolet irradiation was performed in the same manner as in Example 1. That is, the irradiation was performed while the TFT 2 was exposed to light.

Next, two liquid crystal display elements were prepared by laminating two polarizing plates orthogonal to each other on both sides of the cell.

FIG. 4 shows the electro-optical characteristics of the manufactured liquid crystal display device measured in the vertical direction, in which the applied voltage is plotted on the horizontal axis and the transmittance is plotted on the vertical axis. As can be seen from this figure, the applied voltage-transmittance curve is shifted to the high voltage side by about 1 V as compared with the case of the first embodiment. The phenomenon of such a shift is that the phase separation behavior is almost the same as that of Example 1 when observed with a polarization microscope, and therefore the TFT by irradiation of ultraviolet rays on the TFT
It is presumed that this is caused by the deterioration of.

(Comparative Example 2) Further, other comparative examples were prepared. First, in the same manner as in Example 1, polyimide was applied as an alignment film to the substrate by spin coating, and after baking this, rubbing treatment was performed in one direction with a nylon cloth, and two substrates were placed so that the rubbing directions were orthogonal to each other. Cell thickness is 5.
It was pasted so as to have a thickness of 5 μm.

Next, a chiral agent S is placed between the obtained cells.
Liquid crystal material Z containing 0.38% of -811 (manufactured by Merck)
LI-4792 was injected.

Subsequently, polarizing plates were attached to both sides of the cell so that their polarization planes were perpendicular to each other, to prepare a TN type liquid crystal element.

5 (a), (b), (c), (d),
(E) shows the change in the transmittance (vertical axis) with respect to the applied voltage (horizontal axis) in the electro-optical characteristics of the manufactured liquid crystal display element. FIG. 5F shows the direction in which the electro-optical characteristics are measured. These figures are the same as the case of FIG. 2 according to Example 1, and in the liquid crystal display element of Comparative Example 2, an inversion phenomenon, an increase in transmittance at a saturation voltage, and the like were observed, and the viewing angle characteristics became poor. ing.

(Embodiment 2) This embodiment 2 is a case where a liquid crystal display element in which a light shielding layer is formed inside a cell so as to cover the TFT portion of the cell when irradiated with light.

First, as shown in FIG. 6, a Ta film, a part of which is the gate electrode 12, is provided on the glass substrate 11 to a thickness of 3000 angstroms, and an insulating film 13 made of Ta ₂ O ₅ is further formed thereon. The film was formed to a film thickness of 4000 Å, and the amorphous silicon layer 14 was further formed thereon. The Ta film constitutes the gate electrode 12 and the gate bus line.

Next, an insulating film 15 made of, for example, Ta ₂ O ₅ is formed on the amorphous silicon layer 14, and the drain electrode 17 and the source electrode 16 divided on the insulating film 15 are further formed thereon. And formed. The drain electrode 17 and the source electrode 16 and the gate electrode 1 described above.
The TFT 2 is composed of 2 and.

Next, the pixel electrode 1 was formed by partially overlapping the drain electrode 17. As a result, a TFT substrate is manufactured.

Next, the manufactured TFT substrate and the counter substrate having the counter electrode, which has been fabricated in advance, are arranged to face each other.
A black mask, which is positioned so as to cover the TFT of the TFT substrate, is formed in advance on the counter substrate. When the black mask is arranged to face the counter substrate, the black mask covers portions other than the pixel electrodes of the TFT substrate. Both substrates are provided.

Next, a mixture similar to that used in Example 1 is vacuum-injected between the two substrates, and the photomask 25 shown in FIG.
Is bonded to the TFT substrate side of the cell so as to cover the pixel electrode 1, and then ultraviolet irradiation is performed in the same manner as in Example 1. At this time, the gate electrode 12 and the insulating film 13 immediately above the gate electrode 12 function as a light-shielding layer for preventing light from shining on the TFT 2 portion thereon. The insulating film 13 immediately above the gate electrode 12 is made of Ta ₂ O ₅ or Si.
O _X, to use a transparent inorganic material such as SiN _X preferred.
The shape of the TFT2 to be covered is not particularly limited, but the TFT2 should be covered so that the mixture in the cell is sufficiently irradiated with ultraviolet rays.
It is preferable that it is sufficiently covered and has a minimum size.

FIG. 7 is a schematic view showing the result of observing the liquid crystal display device thus manufactured with a polarization microscope. As can be understood from this figure, the display medium formed in the cell has the liquid crystal region 21 for each picture element as in the first embodiment.
And a liquid crystal domain 23 is radially aligned around the polymer island 22 at the center.
In the figure, 20 is a transparent portion of the black mask, 23a is a disclination line, and 24 is a polymer wall.
The manufactured liquid crystal display device has excellent electro-optical characteristics as in the case of Example 1 in terms of viewing angle characteristics, and has little reversal phenomenon in which the contrast is reversed depending on the viewing angle direction or contrast change depending on the viewing angle direction. .

(Third Embodiment) The third embodiment is a case where a display medium is formed by irradiating light from the side of the counter substrate which is arranged to face the TFT substrate and has a black mask. The contents will be described below.

First, as shown in FIG. 8, the thickness is 1.1 mm.
On the glass substrate 32 of, the black mask 30 and the thickness 5
A counter electrode 33 made of transparent ITO of 00 angstrom was formed, and a counter substrate 34 for 4 inches was prepared.
As shown in FIG. 9, the black mask 30 has a light-shielding portion 30a in which a portion that becomes a picture element is opened. Further, as in the first embodiment, a 4-inch T having a picture element electrode 35 and the like is used.
The FT substrate 36 was produced.

Next, the two substrates 3 were not coated with the alignment film.
4, 36 are made to face each other with the glass substrate side facing outward,
A 5.5 μm spacer (not shown) was interposed between the two substrates 34 and 36 to keep the cell thickness constant to form a cell.

Next, on the counter substrate side of the prepared cell,
As shown in FIG. 10, the photomask 25 having the light transmitting hole 25b at the substantially center of the light shielding portion 25a for covering the pixel electrode 35 was aligned, and then the cell and the photomask 25 were fixed with an ultraviolet curable resin.

Next, 0.1 g of R-684 (manufactured by Nippon Kayaku Co., Ltd.), 0.05 g of styrene, 0.75 g of isobornyl methacrylate, 0.10 g of perfluorooctyl methacrylate and chiral. 4 g of liquid crystal material ZLI-47 containing 0.3% of agent S-811 (manufactured by Merck)
92 and 0.0025 g of photopolymerization developer Irugacure 65
The mixture mixed with 1 (manufactured by Ciba Geigy) was vacuum-injected into the cell at 40 ° C.

Next, maintaining the same temperature of 40 ° C.,
10 mW / cm under high pressure mercury lamp that can obtain parallel rays
^{At position 2} , the mixture in the cell was irradiated with light from the photomask 25 side as shown in FIG. This irradiation is, for example, 1
20 cycles of irradiation for 2 seconds and no irradiation for 30 seconds were performed, followed by continuous irradiation for 10 minutes, and then the photomask 25 was removed and ultraviolet irradiation was continuously performed for 10 minutes.

At this time, if the black mask 30 is formed to have a size corresponding to the light transmitting portion of the photomask 25 covering the pixel electrode 35, it becomes difficult for light to enter the cell and a desired display medium is obtained. Can no longer be formed. Therefore, in this embodiment, the portion covered by the black mask 30 is
The area is 70% or less of the total area other than the pixel electrode 35 which is not covered with the photomask 25.

This irradiation cures the resin in the mixture to form a liquid crystal region 38 surrounded by the polymer wall 37 at the pixel electrode 35 portion, and the liquid crystal region 38 has liquid crystal domains radially. It becomes a state. The light-transmitting hole 25b provided in the photomask 25 at substantially the center of the light-shielding portion 25a is for making the liquid crystal domains radial.

A liquid crystal display device was manufactured by laminating two polarizing plates orthogonal to each other on both sides of the cell thus manufactured.

Among the electro-optical characteristics of the produced liquid crystal display element, the viewing angle characteristics were excellent characteristics with little inversion phenomenon in which the contrast was reversed depending on the viewing angle and little change in contrast depending on the viewing angle direction. Furthermore, when the cell was observed with a polarization microscope, it was found that the liquid crystal was concentrated in the pixel region.

In the present invention, the reason why the portion covered by the black mask 30 as described above is 70% or less of the total area of the portion other than the pixel electrodes not covered by the photomask 25 is as follows. by. That is, when it exceeds 70%, the irradiation region is insufficient and the shape of the polymer wall is not determined, so that the polymer wall gets into the picture element, resulting in a decrease in contrast.

The portion covered by the black mask 30 is
As a method of making 70% or less of the total area of the portion other than the pixel electrodes not covered with the photomask 25, the inner peripheral edge of the transparent portion of the black mask 30 is made larger than the outer peripheral edge of the photomask 25, or As shown in FIG. 11, it is possible to partially open the light-shielding portion of the black mask 30 to provide the light-transmitting portion 30b, or to employ both of them.

Comparative Example 3 The following was prepared as a comparative example.

First, a TFT substrate similar to that of the third embodiment and an opposite substrate provided with a black mask 31 having a light transmitting portion 31a other than the pixel electrodes as shown in FIG. 12 are used.
A cell was prepared in the same manner as in Example 3. In this case, if the transparent portion 31a is formed smaller than the pixel electrode, the transparent portion 31a has the size of the pixel.

Next, a photomask was attached to the TFT substrate side of the manufactured cell, and subsequently, the same display medium material as that used in Example 3 was injected into the cell and ultraviolet curing was performed.

The cell thus produced was divided into two substrates in liquid nitrogen, and the polymer material after the liquid crystal material was poured out with acetone was observed by SEM (scanning electron microscope). FIG. 13 shows the observation result. As shown in this figure, the liquid crystal region 38 is formed also in the display medium portion corresponding to the gate bus line, and the polymer wall 37 extends to the pixel portion. It was structured.

Table 1 shows the light transmittance of the liquid crystal display elements of the above-mentioned Example 3 and Comparative Example 3 in which two polarizing plates which are orthogonal to each other are attached to both sides of the cell when no voltage is applied.
In addition, the measurement of the light transmittance was performed by using 100% of two polarizing plates in which the black mask used and the polarization axis were aligned (blank).
Went as.

[0061]

[Table 1]

As can be seen from this table, in the case of Example 3, the light transmittance when no voltage was applied was sufficiently higher than that of Comparative Example 3.

Further, in the case of irradiating light from the counter substrate side as in the above-mentioned third embodiment, there are the following advantages. That is, in the case of Comparative Example 3, since the amount of light reaching the cell is insufficient and various problems occur as described above, conventionally, in the conventional case, the TFT on the side opposite to the counter substrate on which the black mask is formed is usually used. A photomask is installed on the substrate side, and TFT
The cell is irradiated with light from the substrate side. However, in such a case, since the gate bus line and the source bus line made of a light-shielding material are formed on the TFT substrate, the liquid crystal region is formed in the portion corresponding to them and the pixel bus line is formed. The structure is such that the polymer wall extends even into the part. On the other hand, in the present invention, since light is emitted from the counter substrate side, there is an advantage that such a structure can be prevented.

(Embodiment 4) Embodiment 4 is a case where the photomask and the cell can be easily aligned with each other. The contents will be described below.

First, as shown in FIG. 14, the thickness is 1.1 m.
On a glass substrate 32 of m, a black mask 30 for transmitting light only to the pixel portion and a counter electrode 33 made of ITO having a thickness of 500 angstrom are formed to form a counter substrate 3
4 is produced. Further, as shown in FIGS. 14 and 15A, a 4-inch TFT substrate 36 having a plus marker c is formed outside the display region 39 in which many pixel electrodes are formed. The details of the marker c are shown in FIG.
Shown in.

Next, the two substrates 3 were not coated with the alignment film.
The cells 4 and 36 are arranged so as to face each other with the glass substrate side facing outward, and a 5.5 μm spacer (not shown) is interposed between the substrates 34 and 36 to keep the cell thickness constant. Configured the cell.

Next, on the TFT substrate 36 of the above cell,
As shown in FIGS. 14 and 16A, a photomask 40 having a marker e having a shape obtained by extracting the plus mark of the marker c from a square outside the photomask region 40a.
While looking at both markers c and e with a microscope,
After that, both substrates 34 and 36 were fixed with an ultraviolet curable resin. In this case, when the marker c of the cell and the marker e of the photomask 40 are overlapped with each other, there is no gap between the markers c and e and light leakage does not occur, so that accurate alignment is possible. 16B shows the details of the marker e, and FIG. 16C shows the photomask 40.
The positional relationship between the light-shielding portion (shown by the broken line) and the pixel area (solid line) that is the light-transmitting portion of the black mask 30 is shown.

Next, 0.1 g of R-684 (manufactured by Nippon Kayaku Co., Ltd.), 0.05 g of styrene, 0.75 g of isobornyl methacrylate, 0.10 g of perfluorooctyl methacrylate and chiral. 4 g of liquid crystal material ZLI-47 containing 0.3% of agent S-811 (manufactured by Merck)
92 and 0.0025 g of photopolymerization developer Irugacure 65
The mixture mixed with 1 (manufactured by Ciba Geigy) was vacuum-injected into the cell at 40 ° C.

Next, maintaining the same temperature, a parallel light beam can be obtained from the photomask side under a high pressure mercury lamp 10 mW / c
At m ² , the mixture was irradiated with light as follows. That is, 20 cycles of irradiation for 1 second and no irradiation for 30 seconds were carried out, followed by continuous irradiation for 10 minutes, removing the photomask, and continuously irradiating with ultraviolet rays for 10 minutes. By this irradiation, the resin in the mixture was cured to obtain a display medium in which a liquid crystal domain in which liquid crystal domains were radially arranged was surrounded by a polymer wall.

A liquid crystal display device was produced by laminating two polarizing plates which were orthogonal to each other on both sides of the produced cell.

In the manufactured liquid crystal display element, the cell and the photomask are accurately aligned, so that the liquid crystal region and the polymer wall are arranged at desired positions. Further, the viewing angle characteristics of the liquid crystal display element are excellent characteristics in which there is little inversion phenomenon in which the contrast is reversed depending on the viewing angle direction and there is little change in the contrast depending on the viewing angle direction. Furthermore, when the cell was observed with a polarization microscope, it was found that the liquid crystal was concentrated in the pixel region.

Comparative Example 4 An attempt was made to attach a photomask to the TFT substrate side of a cell using a TFT substrate without a marker (same as in Example 4 except that there is no marker) with a microscope. However, since the thickness of the TFT substrate was 1.1 μm, the patterns of the photomask and the substrate could not be observed at the same time, and bonding was extremely difficult.

In the fourth embodiment, a marker is used for positioning the photomask and the cell, but the marker can be installed in the following manner. That is,
The position of the marker may be within the display area having a TFT or the like, or as shown in FIG. 15, it may be located on the outer peripheral portion which does not form the display area 39. Also, since the pattern of each picture element or TFT can be used as a marker, the inner pattern of the cell is formed on the outer surface by using photolithography,
The formed pattern may be used. These markers are made so as to correspond to the markers installed on the photomask, respectively, and when the photomask is attached, the light-shielding portion is appropriately arranged on each pixel by aligning the markers on the substrate and the photomask. Designed to be. Further, as shown in FIG. 7, when a plurality of cells 42 are manufactured from one substrate 41 material, each cell 42 is connected by an injection port 43 for injecting a mixture for a display medium. When the seal pattern 44 having the structure is used, the following is preferable. That is, after injecting a mixture of a liquid crystal material, a photocurable resin, a photopolymerization initiator and the like into the cell 42 through the injection port 43, the cell 42 is covered with a photomask and polymerized by ultraviolet rays, which does not substantially contribute to the display of the cell 42. Form a marker on the part. This way,
By covering a plurality of cells 42 with a photomask all at once, the cells 42 can be manufactured all at once.

Regarding the number of markers, since the markers are for determining the planar position, it is necessary to provide the markers at two or more places. The positions of the markers are preferably set so that the adjacent markers are separated from each other, and as shown in FIG. 15A, a plurality of markers are provided at four corners avoiding the display area 39 or between the four corners. Preferably.

As the material of the marker, a material having a high reflectance, for example, a metal such as aluminum, tantalum, molybdenum, or the like can be used so that it can be easily recognized when observed by a microscope, and a resin to which a dye is added is used. Can be used. The marker made of these materials may or may not be removed with a solvent, an etching agent, or the like after the cell is manufactured.

(Fifth Embodiment) The fifth embodiment is a case where the alignment between the photomask and the cell can be eliminated.
The procedure is as follows.

First, using the cell of Comparative Example 4, a negative photoresist, for example, OMR84 (manufactured by Tokyo Applied Chemistry Co., Ltd.) containing 10% of carbon black was applied to the outside of the TFT substrate of the cell by spin coating. Ultraviolet rays were irradiated from the counter substrate side, and a light-shielding layer having a shape opposite to the light-shielding portion of the black mask was made to appear on the TFT substrate side with a developing solution. At this time, since the black mask transmits light only to the picture element portion, the light shielding layer is formed so as to cover only the picture element portion.

Next, the same liquid crystal material as in Example 4 is injected into the cell, and ultraviolet rays are irradiated from the TFT substrate side as in Example 4. At this time, as described above, since the light shielding layer is formed so as to cover only the picture element portion and functions as the photomask of the fourth embodiment, the polymer wall made of the resin in the liquid crystal material is formed in the portion other than the picture element portion. A liquid crystal region is formed, which is surrounded by the polymer wall in the pixel portion.

Next, the light-shielding layer was removed with a stripping solution to prepare a cell.

When the manufactured cell was observed with a polarization microscope, the liquid crystal region was concentrated in the picture element portion, and the liquid crystal region was formed by a plurality of liquid crystal domains. When polarizing plates were attached to the produced cell so as to be orthogonal to each other, the viewing angle characteristics of the liquid crystal display element were excellent as in Example 4.

Regarding the material of the light-shielding layer used in the fifth embodiment, when the liquid crystal display element is used in a transmission type, the light-shielding layer must be removed after the cell is manufactured, for example, after irradiation with ultraviolet rays. It is possible to use an easy-to-use material, for example, an organic polymer compound containing a compound that absorbs ultraviolet rays, such as a dye or carbon black. Further, when the cell is manufactured as a reflective type, it is not necessary to remove the light shielding layer after the cell is manufactured. Therefore, a metal thin film or the like that can be used as a reflector may be used in advance.

In Examples 4 and 5 described above, the photomask and the light-shielding layer are accurately aligned with the cells by forming a liquid crystal region in the pixel portion and a polymer wall in the portion other than the pixel. This is to prevent the polymer wall from getting into the pixel portion. In addition, this is to prevent the TFT portion from being irradiated with light.

In each of the above embodiments, T is used as an active element.
Although the FT is used, the present invention is not limited to this, and it is needless to say that the present invention can be similarly applied to a liquid crystal display element using other active elements such as MIM.

Although not explicitly stated in the above description, the present invention is applied to a liquid crystal display device in which the liquid crystal domains forming the above-mentioned liquid crystal region are aligned radially or randomly and the liquid crystal region is surrounded by a polymer wall. However, most other modes that can be driven actively, such as TN, STN, F
It can also be applied to liquid crystal display devices of LC and ECB modes.

The liquid crystal materials usable in the present invention include those mentioned above, but the following materials can be used. That is, it is an organic mixture that exhibits a liquid crystal state at around room temperature and is a nematic liquid crystal (liquid crystal for dual frequency drive,
Liquid crystals with Δε <0), cholesteric liquid crystals (especially,
A liquid crystal having a selective reflection property for visible light), a smectic liquid crystal, a ferroelectric liquid crystal, a discotic liquid crystal, or the like can be used. These liquid crystals may be used alone,
Alternatively, they may be mixed and used. In particular, a nematic liquid crystal, a nematic liquid crystal to which a cholesteric liquid crystal (chiral agent) is added, or a ferroelectric liquid crystal is preferable in terms of characteristics. More preferably, a liquid crystal having excellent chemical reaction resistance is preferable because it is accompanied by a photopolymerization reaction during processing. Specifically, in the compound,
It is a liquid crystal having a functional group such as a fluorine atom. Specifically, ZLI-4801-000 and ZLI-4801-0
01, ZLI-4792 (manufactured by Merck & Co., Inc.) and the like.

As the material of the alignment film that can be used in the present invention, an organic film such as SE150 (Nissan Chemical) or CYTOP (Asahi Glass), such as polyimide, or Si is used.
An inorganic film such as O can be used. The alignment film may be subjected to an alignment treatment such as rubbing if necessary. further,
In a liquid crystal display device in which liquid crystal domains are oriented in random directions, a thin film having the same effect as the alignment film is automatically formed between the substrate and the liquid crystal region during the device manufacturing process, and thus the formation of the alignment film is omitted. May be.

[0087]

As described above in detail, in the case of the present invention, the active element is covered with a photomask, a light-shielding layer, or another light-shielding layer and irradiated with light, so that the active element is not irradiated with light. Therefore, it is possible to prevent the active element from deteriorating, so that it is possible to prevent a change in the voltage characteristic.
Further, it is possible to suppress the inversion phenomenon in which the contrast is reversed depending on the viewing angle direction and the contrast change depending on the viewing angle direction. Furthermore, in the case where a marker for alignment is formed on the photomask and the substrate, the photomask and the substrate can be easily aligned based on the marker, and in particular, one of the markers has a shape in which a part of the other is extracted. If done, it can be aligned accurately. Further, when the light-shielding layer is formed on the outside of the cell by using, for example, a negative photoresist, the alignment between the cell and the light-shielding portion can be eliminated and the alignment can be accurately performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a part of a liquid crystal display element produced in Example 1 and showing a photomask used.

2A to 2E are diagrams showing electro-optical characteristics of the liquid crystal display element manufactured in Example 1, and FIG. 2F is a diagram showing measuring directions of the electro-optical characteristics.

FIG. 3 is a diagram showing a part of a liquid crystal display device produced in Comparative Example 1 and a photomask used.

FIG. 4 is a diagram showing electro-optical characteristics of a liquid crystal display device manufactured in Comparative Example 1.

5A to 5E are diagrams showing electro-optical characteristics of the liquid crystal display device produced in Comparative Example 2, and FIG. 5F is a diagram showing measuring directions of the electro-optical characteristics.

FIG. 6 is a cross-sectional view showing a TFT portion included in the liquid crystal display element manufactured in Example 2.

FIG. 7 is a schematic view showing one picture element portion of the liquid crystal display element manufactured in Example 2.

FIG. 8 is a cross-sectional view showing a liquid crystal display element manufactured in Example 3.

FIG. 9 is a plan view showing a black mask provided in the liquid crystal display element manufactured in Example 3.

FIG. 10 is a plan view showing an example of a photomask used in a third embodiment.

FIG. 11 is a plan view showing another photomask example used in the third embodiment.

12 is a plan view showing a photomask used in Comparative Example 3. FIG.

13 is a plan view showing a state in which a liquid crystal region and a polymer wall of a liquid crystal display element manufactured in Comparative Example 3 are formed.

FIG. 14 is a cross-sectional view showing a liquid crystal display element manufactured in Example 4.

15A is a diagram showing a position where a marker is provided on a substrate of the liquid crystal display element manufactured in Example 4, and FIG. 15B is a diagram showing the marker in detail.

16A is a diagram showing a position where a marker is provided on a photomask used in manufacturing the liquid crystal display element of Example 4, and FIG. 16B is a diagram showing the marker in detail.
(C) is a diagram showing a positional relationship between a pixel region and a light-shielding portion of a photomask.

FIG. 17 is a plan view showing a seal pattern used when a plurality of cells are collectively manufactured.

[Explanation of symbols]

 1 pixel electrode 2 TFT (thin film transistor) 3 source bus line (signal line) 4 gate bus line (scanning line) 5 photomask 5a light-shielding portion 5b light transmitting hole 11 glass substrate 12 gate electrode 13 insulating film 14 amorphous silicon layer 15 insulating film 16 Source Electrode 17 Drain Electrode 20 Black Mask Light Shield 21 Liquid Crystal Region 22 Polymer Island 23 Liquid Crystal Domain 23a Disclination Line 24 Polymer Wall 25 Photo Mask 25a Light Shield 25b Light Transmission Hole 30 Black Mask 30a Black Mask Light Transmission Part 30b Light-transmitting part provided on the light-shielding part of the black mask 32 Glass substrate 33 Counter electrode 34 Counter substrate 35 Pixel electrode 36 TFT substrate 37 Polymer wall 38 Liquid crystal region 39 Display region 40 Photomask 40a Photomask region c Marker e Marker 41 substrate 42 cell 43 inlet 44 seal pattern

Claims (8)

[Claims] 1. Two substrates are arranged facing each other with a display medium having a liquid crystal region surrounded by a polymer wall sandwiched therebetween, and picture elements for displaying are arranged in a matrix, and In a method of manufacturing a liquid crystal display element in which an active element is provided on a substrate, the step of disposing two substrates facing each other, and including at least a liquid crystal material and a photopolymerizable resin between the two substrates facing each other. A method of manufacturing a liquid crystal display device, comprising the steps of injecting a mixture and irradiating the mixture with light by using the picture elements and active elements as non-light irradiation regions. 2. The liquid crystal display element according to claim 1, wherein the means for forming the non-light irradiation region is a photomask, the photomask is provided on the other substrate side, and light is emitted from the other substrate side. Manufacturing method. 3. The means for forming the non-light-irradiated region is a light-shielding layer provided on the one or the other substrate for the active element, and the pixel is provided outside the substrate having the light-shielding layer. It is a photomask arranged,
The method for manufacturing a liquid crystal display element according to claim 1, wherein light is irradiated from the photomask side. 4. The light-shielding layer is a black mask having a pixel portion as a light-transmitting portion, the photomask is provided so as to cover all or part of the light-transmitting portion of the black mask, and the black mask is used as the photomask. The method for manufacturing a liquid crystal display device according to claim 3, wherein the method has a larger transparent portion and / or a transparent hole in the light shielding portion of the black mask. 5. The light-shielding layer is a black mask having a pixel portion as a light-transmitting portion, and another light-shielding layer having a shape corresponding to the light-transmitting portion of the black mask is a substrate provided with the black mask. The method for manufacturing a liquid crystal display element according to claim 1, wherein the substrate on the opposite side is formed of a material containing a compound that absorbs light, and the light is irradiated from the side of the other light shielding layer. 6. A marker for alignment is formed on the photomask and the substrate on which the photomask is provided, the photomask and the substrate are aligned based on the marker, and then light is irradiated. The method for manufacturing a liquid crystal display element according to claim 1. 7. One of the markers formed on the photomask and the substrate is formed by extracting a part of the other,
The method for manufacturing a liquid crystal display device according to claim 6, wherein the photomask and the substrate are aligned by superimposing the two markers in a state where no gap exists between the two markers. 8. Two substrates are arranged opposite to each other with a display medium having a liquid crystal region surrounded by a polymer wall sandwiched therebetween, and picture elements for displaying are arranged in a matrix, and In the liquid crystal display element in which the active element is provided on the substrate, the substrate on which the active element is formed has a structure in which a light shielding layer is provided between the base substrate and the active element.