JPH07175047A - Production of liquid crystal panel - Google Patents

Abstract

PURPOSE:To obtain a production method of a macromolecule dispersion liquid crystal panel by which a resin under a black matrix can be hardened. CONSTITUTION:A mixture soln. of a liquid crystal and uncured UV resin is injected between an array substrate 12 and a counter substrate 11. Then, a diffusion plate 18 such as opal glass is stuck to the array substrate 12 through ethylene glycol 20a or the like. Then, the resultant body is irradiated with UV rays 19 from the side of the diffusion plate 18. The UV rays 19 are scattered in the diffusion plate 18 and the scattered light reaches the soln. A part of the light propagates almost parallel to the counter substrate 11 to irradiate the mixture soln. interposed between a source signal line 17 and a black matrix(BM) 16 to cause phase separation of the mixture soln. into the resin component and the liquid crystal component. After the resin in the soln. is hardened, the diffusion plate 18 is removed and the liquid crystal panel 10 is cleaned to obtain a complete product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a liquid crystal panel using a polymer dispersed liquid crystal as a light modulation layer.

[0002]

2. Description of the Related Art A liquid crystal panel has been actively researched and developed because it can be made light and thin. In recent years, a pocket television using a twisted nematic (TN) mode liquid crystal panel in which the optical activity of liquid crystal is applied to image display has been put into practical use. Further, a liquid crystal projection television and a viewfinder using the liquid crystal panel as a light valve have been put into practical use.

However, the liquid crystal panel using the TN liquid crystal is
Since a polarizing plate is required to perform light modulation, there is a problem that display brightness is low. Further, the manufacturing process is complicated, for example, a rubbing process is required to align the liquid crystal molecules. Therefore, in recent years, a liquid crystal panel using a polymer dispersed liquid crystal that does not require rubbing and does not require a polarizing plate for light modulation has been attracting attention. An example of the polymer dispersed liquid crystal panel is disclosed in US Pat. No. 4,435,047.

The polymer-dispersed liquid crystal will be briefly described below with reference to FIG. Polymer dispersed liquid crystals are roughly classified into two types depending on the dispersion state of liquid crystals and polymers. One is a type in which liquid crystals in the form of water droplets are dispersed in a polymer. The liquid crystal exists in the polymer in a discontinuous state. Hereinafter, such a liquid crystal is called PDLC,
A liquid crystal panel using the liquid crystal is called a PD liquid crystal panel. The other type has a structure in which a polymer network is stretched around the liquid crystal layer. It looks like a sponge containing liquid crystal. The liquid crystal is
It does not form a water droplet, but exists continuously. Hereinafter, such a liquid crystal is referred to as PNLC. In order to display an image with the above-mentioned two kinds of liquid crystal panels, light scattering and transmission are controlled.

PDLC utilizes the property that the refractive index differs in the direction in which the liquid crystal is aligned. When no voltage is applied, each water droplet liquid crystal is oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer and the liquid crystal, and incident light is scattered. When a voltage is applied, the alignment direction of the liquid crystal is aligned. If the refractive index when the liquid crystal is oriented in a certain direction is matched with the refractive index of the polymer in advance, incident light is transmitted without being scattered.

On the other hand, PNLC uses the irregularity itself of the alignment of liquid crystal molecules. The incident light is scattered in the irregular alignment state, that is, in the state where no voltage is applied.
On the other hand, when a voltage is applied and the arrangement state is made regular, light is transmitted. Although the present invention is not limited to one of PDLC and PNLC, PDLC will be described as an example for ease of explanation.

In FIGS. 6 (a) and 6 (b), 61 is a water droplet liquid crystal and 62 is a polymer. A thin film transistor (hereinafter referred to as a TFT, not shown) or the like is connected to the pixel electrode 15, and a voltage is applied to the pixel electrode 15 by turning on / off the TFT. The voltage modulates the liquid crystal by changing the liquid crystal alignment direction of the water droplet liquid crystal 61 on the pixel electrode 15. As shown in FIG. 6A, the liquid crystal molecules in each water droplet liquid crystal 61 are aligned in an irregular direction when no voltage is applied (OFF). In this state, a difference in refractive index occurs between the polymer 62 and the liquid crystal, and incident light is scattered.
As shown in FIG. 6B, when a voltage is applied to the pixel electrode 15, the counter electrode 14 of the counter substrate 11 and the pixel electrode 15
The directions of the liquid crystal molecules are aligned. If the refractive index n _o (n _o is an ordinary light refractive index) when the liquid crystal molecules are aligned in a certain direction is matched with the refractive index of the polymer 62 in advance, incident light is not scattered and the pixel electrode 15 side of the array substrate 12 is Exit from.

When the liquid crystal is in the form of water drops as in PDLC, the average value of the diameters of the liquid crystal in water drops is called the average particle size, and in the case of the network as in PNLC, the average value of the hole diameter of the network is This is called the average pore size.

FIG. 7 is an equivalent circuit diagram of a polymer dispersed liquid crystal (hereinafter referred to as PD liquid crystal) panel. Each pixel electrode 15
A TFT 73 is connected to. Further, an additional capacitor 74 is formed to hold the electric charge. TFT
One pixel 75 is composed of 73, the pixel electrode 15, and the like. A gate drive 2C7 is provided for each gate signal line Gi (i = 1 to m).
1 is connected to control ON / OFF of the TFT 73. A source drive IC 72 is connected to the source signal line Sj (j = 1 to n), and the IC 72 outputs a video signal to the source signal line Sj.

A conventional method for manufacturing a PD liquid crystal panel will be described below. In US Pat. No. 4,415,047, the liquid crystal is a nematic liquid crystal, and the polymer 62 is polyvinyl alcohol (PVA). A method is disclosed in which a mixed solution of the polymer 62 and liquid crystal is applied onto an electrode substrate by using a printing technique and then sandwiched between the electrode substrate and the substrate on which the counter electrode is formed.

Japanese Unexamined Patent Publication (Kokai) No. 3-58021 discloses a PD liquid crystal panel using a photocurable acrylic resin as the polymer 62. The manufacturing method is as follows. The electrode surfaces of the two electrode substrates are arranged so as to face each other, and spacers such as beads are scattered inside. A liquid mixture of liquid crystal and uncured resin around the electrode substrate (hereinafter,
A blank cell having a predetermined substrate interval is prepared by sealing with an epoxy-based sealing material except for an injection port for injecting a mixed solution). Next, the mixed solution is injected from the injection port of the empty cell, and the injection port is sealed. UV light (hereafter,
(It is called UV), and the resin is cured to phase-separate the liquid crystal and the resin to complete the process.

[0012]

Problems to be Solved by the Invention US Pat. No. 44150
In the invention described in Japanese Patent No. 47, a nematic liquid crystal is used as the liquid crystal, and PVA is used as the polymer 62.
Further, the mixed solution of the polymer and liquid crystal is applied on the electrode substrate by using a printing technique. However, it is difficult to obtain a uniform liquid crystal film thickness by the printing technique. Therefore,
Brightness unevenness occurs in the display image on the liquid crystal panel. Also, PV
Since A is a water-soluble polymer, it has poor water resistance, and as a result,
It also has the drawback of becoming cloudy and swelling. Further, there is a problem that it takes a long time to cure the resin.

It is not preferable to use PVA as the polymer 62. When mass-producing PD liquid crystal panels, an ultraviolet curable resin (hereinafter referred to as a UV resin) should be used for the polymer 62 as in Japanese Patent Laid-Open No. 3-58021. However, even if the UV resin is used, the conventional liquid crystal panel manufacturing method has a problem due to the structure of the panel.
Hereinafter, the problem will be described.

FIG. 3 is an explanatory view of a conventional liquid crystal panel manufacturing method using a UV resin as a polymer. The array substrate 12 on which the source signal line 17 and the pixel electrode 15 are formed, the counter electrode 14 and the black matrix 16
The counter substrate 11 on which is formed is bonded, and the mixed solution is injected between both substrates. After that, irradiate UV light to UV
The resin is cured.

The black matrix (hereinafter referred to as BM) 16 is formed of a metal thin film such as chromium (Cr). On the other hand, the source signal 17 is also formed of a metal thin film. Therefore, UV light is not transmitted. Similarly, the UV light does not pass through the region where the gate signal line and the TFT are formed.
The BM 16 is formed to prevent light leakage from the source signal line or the peripheral portion of the TFT. Therefore, as shown in (FIG. 3), the source signal and the like and the BM are arranged at the overlapping position.

When ultraviolet rays are made to enter the array substrate 12 perpendicularly, the ultraviolet rays 31 are reflected by the source signal lines 17a and are not applied to the portion A of the liquid crystal layer 13. Therefore, the resin in the portion A does not cure.

In order to irradiate the lower portion of the source signal line 17 with UV light, even if the light is incident on the array substrate 12 at an angle, such as 32a and 32b, the region B under the source signal line 17b is irradiated with UV light. Not done. Angle of incidence θ _{1 with} respect to angle of incidence θ ₂
Is smaller according to Snell's law. The medium on the incident side is air, the refractive index n _{2 of which} is 1.0, and the array substrate 12
Is glass, and its refractive index n ₁ is about 1.5. Therefore, even if the UV light 32 is obliquely incident on the array substrate 12, the angle θ _{1 with} respect to the normal line of the substrate is small within the array substrate 12. That is, B
Almost no UV light is incident on the region.

As a matter of course, from the counter substrate 11 side, U
Even when irradiated with V light, an uncured region is formed. From the above, the resin could not be cured over the entire liquid crystal layer by the conventional manufacturing method.

If the uncured resin remains, the counter substrate 11 or the array substrate 12 and the liquid crystal layer 13 are likely to be separated from each other. In addition, it is easy to change with time.

Further, the problem is that the average particle diameter of the water droplet liquid crystal around the BM 16 becomes large. An explanatory view thereof is shown in (FIG. 4) and (FIG. 5).

In FIG. 4, area B is an area where uncured resin remains. That is, it remains liquid. The area A is an area having an appropriate average particle diameter. The area E is an area in which the average particle diameter is larger than a predetermined value. Seen from the counter substrate 11 (FIG. 5). A region E having a large average particle diameter is formed in the vicinity of the opening 51 of the BM 16.

Generally, when the average particle size of the water droplet liquid crystal is small, the scattering property is improved. However, the driving voltage for making the transparent state becomes high. On the contrary, if the average particle diameter of the water-drop liquid crystal becomes large, the driving voltage becomes low, but at the same time, the scattering characteristic also deteriorates. Since the regions A and B have almost the same liquid crystal film thickness, the amount of light transmission in the region E is large. This means that the amount of transmission of black display increases. Therefore, the display contrast is reduced. Further, since the area E is transmitted with a slight applied voltage, it becomes difficult to perform electro-optical conversion control. It can be said that the above matters are equivalent even if the average particle diameter of the water-drop liquid crystal is replaced with the average pore diameter of the polymer network.

[0023]

The liquid crystal panel of the present invention comprises:
The first to sandwich the mixed solution between the counter substrate and the array substrate
And the optical coupling means, which is an optical coupling means, which is a gel or liquid optical coupling agent (hereinafter, referred to as an OC agent), which substantially matches the refractive index of the array substrate, is applied to the array substrate side and the array substrate and the light diffusion means. A second step of attaching the diffuser plate, which is the above, and irradiating the mixed solution with UV light from the surface on which the diffuser plate is attached to cure the resin component of the mixed solution and phase-separate the liquid crystal component and the resin component. The third step is performed. More preferably, an OC agent is applied to the counter substrate side, and a mirror or the like serving as a light reflecting means is attached.

[0024]

When the UV light is incident on the diffusion plate, it scatters. When the array substrate and the diffusion plate are optically coupled, light is not refracted between the plates. That is, the light scattered by the diffusion plate goes straight to the mixed liquid crystal layer of the PD liquid crystal panel. If the diffuser plate is in a completely diffused state, the diffused light travels in a certain direction. Part of the light becomes UV light that travels in parallel in the array substrate 12, and B
It enters the mixed solution layer 13 sandwiched between the M16 and the source signal line 17. The incident light cures the UV resin.

[0025]

EXAMPLES A method for manufacturing a liquid crystal panel of the present invention will be described below with reference to (FIG. 1).

First, the array substrate 12 or the counter substrate 1
A sealing resin (not shown) is applied to the peripheral portion of the display region 1. The sealing resin is mixed with fibers, beads or the like in order to obtain a desired height. This height becomes the film thickness of the liquid crystal layer 13 of the liquid crystal panel. Therefore, if the thickness of the liquid crystal layer is 15 μm, beads having a diameter of 15 μm are mixed. As the sealing resin, it is preferable to use an ultraviolet curing type. After the sealing resin is applied and the substrates 11 and 12 are bonded together, ultraviolet rays are irradiated to cure the resin. The panel to which the substrates are attached is called an empty cell.

There are several methods for injecting a mixed solution of liquid crystal and uncured resin into an empty cell. The pressure injection method is to inject the mixed solution by pressurizing it through a hole having a diameter of 1 to 2 mm formed around the counter substrate 11. In the vacuum injection method, a vacuum is applied between the counter substrate 11 and the array substrate 12, the injection port is immersed in the mixed solution, and the mixed solution is pulled into the gap.

In the vacuum injection method, it is difficult to obtain the light modulation layer 13 having good scattering characteristics because the components such as the monomer are scattered from the mixed solution when the vacuum is applied. In the present invention, a pressure injection method of injecting the mixed solution from the injection port is adopted. The injection port may not be formed in the counter substrate 11. For example, a part of the sealing resin may be cut and the cut portion may be used as an injection port.

The liquid crystal material of the mixed solution is preferably a nematic liquid crystal, a smectic liquid crystal or a cholesteric liquid crystal, and may be a single liquid crystal compound or a mixture of two or more liquid crystal compounds or a substance other than the liquid crystal compound. Among the above-mentioned liquid crystal materials, a cyanobiphenyl nematic liquid crystal or a chloro nematic liquid crystal having a relatively large difference between the extraordinary light refractive index n _e and the ordinary light refractive index n _o is most preferable. In particular, chlorinated liquid crystals are stable against changes with time, and the retention rate can be increased by forming a PD liquid crystal layer using the liquid crystals. As the resin material, a transparent polymer is preferable, and as the polymer, it is preferable to use an ultraviolet curable resin from the viewpoint of ease of manufacturing process, separation from the liquid crystal layer and the like. As a specific example, an ultraviolet curable acrylic resin is exemplified, and a resin containing an acrylic monomer or an acrylic oligomer which is polymerized and cured by ultraviolet irradiation is particularly preferable.

Examples of such a polymer-forming monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, neopentyl glycol acrylate, hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, and triethylene glycol diacrylate. Examples are methylolpropane triacrylate, pentaerythritol acrylate and the like.

Examples of the oligomer or prepolymer include polyester acrylate, epoxy acrylate and polyurethane acrylate.

A polymerization initiator may be used in order to carry out the polymerization rapidly, and an example thereof is 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-
On (Merck's "Darocur 1116"), 1-vidroxycyclohexyl phenyl ketone (Ciba-Gaiki "Irgacure 184"), benzyl methyl ketal (Ciba-Geigy "Irgacure 651"), etc. are mentioned. In addition, a chain transfer agent, a photosensitizer, a dye, a cross-linking agent and the like can be appropriately used in combination as optional components.

The refractive index n _p when the resin material is cured
And the ordinary refractive index n _o of the liquid crystal are made to substantially match.
When an electric field is applied to the liquid crystal layer, the liquid crystal molecules are oriented in one direction, and the refractive index of the liquid crystal layer becomes n _o . Therefore, the refractive index n _{p of the} resin matches, and the liquid crystal layer is in a light transmitting state. If the difference between the refractive indices n _p and n _o is large, the liquid crystal layer will not be completely transparent even when a voltage is applied to the liquid crystal layer, and the display brightness will decrease.

The ratio of the liquid crystal material in the polymer dispersed liquid crystal layer is 5
About 0% to 90% by weight is preferable, and about 60% to 85% by weight is preferable. If it is 50% by weight or less, the amount of liquid crystal droplets is small, the effect of scattering is poor, and the driving voltage becomes high. On the other hand, when it is 90% by weight or more, the polymer and the liquid crystal tend to be phase-separated into upper and lower two layers, the ratio of the interface becomes small, and the scattering property deteriorates. The structure of the polymer-dispersed liquid crystal layer changes depending on the liquid crystal fraction, and at about 50% by weight or less, the liquid crystal droplets exist as independent droplets,
If it is 50% by weight or more, a continuous layer in which the polymer and the liquid crystal are intricately formed is formed. The thickness of the liquid crystal layer 13 is preferably in the range of 8 to 25 μm, more preferably 10 to 20 μm. If the film thickness is thin, the scattering characteristics are poor and the contrast cannot be obtained. On the contrary, if the film thickness is thick, high voltage driving must be performed, which makes it difficult to design a drive IC for applying a signal to the pixel electrode.

Further, the weight ratio of liquid crystal is 55% or more and 65% or more.
It is preferably not more than 75% and not more than 85%. The weight ratio of liquid crystal is about 55% in the ratio of monomer to oligomer.
When the ratio is 65% or less, it is in the range of 5: 5 to 4: 6, and when the weight ratio of the liquid crystal is 75% or more and 85% or less, it is in the range of 9: 1 to 8: 2. A high-performance liquid crystal layer can be realized. Above all, it is preferable that the weight ratio of the liquid crystal is around 60% and the ratio of the monomer and the oligomer is around 4: 6.

Next, the OC agent 20a is applied to the array substrate 12 or the diffusing means 18 to diffuse the diffusing means 18 and the array substrate 1.
And 2 are optically coupled. What is important is that the refractive index of the OC agent 20a is substantially the same as the refractive index of the array substrate 12. Normally, glass is used as the array substrate 12,
Its refractive index is around 1.5. Therefore, OC agent 2
The refractive index of 0a is preferably 1.3 or more. Examples of the material satisfying the above conditions include liquids such as UV resin, transparent silicone resin, epoxy resin and ethylene glycol. Alcohols also have a refractive index of 1.
Around 4 can be used in many cases, and water can also be used because the refractive index is about 1.3. Also, an adhesive may be used. However, it is preferable that the refractive index of the OC agent be as equal as possible to the refractive index of the array substrate. This is clear if the critical angle is calculated by substituting the refractive index into Snell's law. According to experiments, it is preferable that the critical angle θ ₁ is 60 degrees or more.

In particular, when the OC agent 20 is a UV resin, it is effective. When UV light is irradiated to phase-separate the mixed solution 13, the OC agent 20 is simultaneously cured. After the mixed solution 13 is phase-separated, the diffusing means 18 is removed. At that time, the OC agent 20 is also peeled off and removed. Therefore, it is not necessary to wash off the OC agent by washing.

Examples of the diffusing means 18 include opal glass, frosted glass whose surface is chemically roughened, and a diffusing plate in which a diffusing material is dispersed in a resin used for a backlight of a liquid crystal panel. Also, it may be in the form of a film. Hereinafter, the diffusing means is generically called a diffusing plate. It is desirable that the diffuser plate is in a completely diffused state, and opal glass is preferable in this sense. However, the high price is a drawback. A diffusion plate used for a liquid crystal panel absorbs light to some extent, but is inexpensive. UV to irradiate when absorbing light
The intensity of light may be adjusted. For mass production, the diffuser plate may be used.

It will be apparent that the diffusing means 18 may be a diffractive plate using a diffractive effect, in addition to the diffusing plate which scatters the light. The diffractive plate is a film or plate-shaped material having fine irregularities formed thereon, and changes the traveling direction of incident light by a diffraction effect. It may also be a microlens array. Therefore, the diffusing means 18 should be considered as a means for changing the traveling direction of light.

In addition, there is a method in which the diffusion means 18 is not used. This is a method in which a gel in which a diffusing agent is dispersed is directly applied to an array substrate or the like. The gel is an adhesive, a silicone resin, a UV resin or the like. Incident light is scattered in the gel. No diffuser is used. After phase separation of the mixed solution, the gel is removed.

In particular, it is preferable to use a gel in which a diffusing agent is dispersed in UV resin. The gel is applied onto panel 10 using screen printing techniques. Next, UV light is irradiated to cure the mixed solution 13. At that time, the gel is simultaneously cured. After phase separation of the mixed solution 13, the cured gel is peeled off. Therefore, the subsequent panel cleaning process becomes unnecessary. After applying the gel to the panel 10, the gel may be irradiated with UV light to cure the gel, and then the mixed solution 13 may be injected into the panel to phase-separate the mixed solution 13.

The diffusion plate 18 is attached to the array substrate 12 side because the light transmission region (aperture area of pixels) of the PD liquid crystal panel 10 is large. Since the BM 16 is formed on the counter substrate 11 side, the light transmission region is narrower than the previous region.

A high pressure mercury lamp is used as a source of UV light. A high pressure mercury lamp is not an ideal point light source. Therefore, when the PD liquid crystal panel 10 is irradiated with light, a light intensity distribution is generated on the panel surface. However, in the present invention, the diffusion plate 1
Since 8 is used, light is scattered in the diffuser plate 18 and no light intensity distribution is generated. For this reason also, the effect of using the diffusion plate 18 is effective.

The UV light 19 is scattered when it enters the diffusion plate 18. The scattered light is the OC agent 20a and the array substrate 12
To reach the mixed solution layer 13. If the diffuser plate 18 is in a completely diffused state, UV light that travels in a direction substantially perpendicular to the normal line of the array substrate 12 is also generated. The UV light also enters under the source signal line 17. Therefore, the resin under the source signal line 17 is cured by the UV light, and the liquid crystal component and the resin component are phase-separated. Further, the light incident on the interface between the air and the counter substrate 11 at an angle equal to or greater than the total critical angle returns to the mixed solution 13 layer again.

By attaching the diffuser plate 18, the amount of UV light diffusely reflected in the liquid crystal panel increases, and the resin is hardened over almost the entire area of the liquid crystal 13 layer. Therefore, the B or E region shown in (FIG. 4) does not occur.

Temperature control when irradiating with UV light is also important in manufacturing. When irradiating with UV light, it is necessary to heat the mixed solution with a heater plate or the like. The mixed solution is cloudy at room temperature. Although the temperature at which the polymer is in the isotropic state differs depending on the polymer and the liquid crystal material, when heated, the mixed solution becomes transparent and becomes light transmissive. The heating is performed above the nematic-isotropic phase transition temperature of the mixed solution. UV light has an intensity of about 20 to 150 mW / cm ² for 30 seconds to 1 depending on the spectral distribution.
Irradiate for about 80 seconds. It also depends on the characteristics of the diffusing means 18. The intensity of UV light is determined in consideration of the light diffusion characteristic and the light absorption rate of the diffusion means. Regarding these temperatures and the irradiation conditions of ultraviolet rays, the phase diagram of the liquid crystal weight ratio and the phase transition temperature must be drawn by experiment. If the conditions are not appropriate, the particle size of the liquid crystal will change over time and the scattering characteristics will deteriorate.

After irradiating UV light to phase-separate the mixed liquid crystal, the diffusion plate 18 is removed. After that, the liquid crystal panel 10
Is washed and completed.

Furthermore, in order to prevent the uncured resin region B from being generated and to make the average particle diameter of the water-drop liquid crystal uniform over the entire liquid crystal 13 layer, as shown in FIG. You can attach 21. Examples of the reflection plate 21 include a glass substrate on which aluminum (Al) is vapor-deposited and a SiO ₂ film is formed on the Al as a protective film, and an aluminum plate. Alternatively, a dielectric thin film may be formed in multiple layers on a glass substrate to reflect light by an interference effect. For example, it is a dichroic mirror. The same OC agent as described above is used. Further, instead of the reflecting plate 21, a diffusing plate equivalent to the diffusing means 18 may be arranged. The UV light emitted from the counter substrate 11 is backscattered by the diffusion plate and returns to the mixed solution layer 13. Further, it may be replaced with a reflection plate having fine irregularities on the surface. For example, a plate obtained by embossing an aluminum plate is exemplified. UV light is scattered by the irregularities and returns to the mixed solution layer 13.

With the above-described structure, the UV light 19b which has been transmitted through the counter substrate 19 in the method of FIG. 1 is reflected by the reflection plate 21 and returns to the mixed liquid crystal layer 13 again. Therefore, the proportion of UV light diffusely reflected in the liquid crystal panel 10 is increased, and the droplet-shaped liquid crystal can have a more uniform particle size than the method of FIG.

In the embodiment of the present invention, after the mixed solution is sandwiched between the counter substrate 11 and the array substrate 12, the diffusion plate 18 is connected to the array substrate 12 via the OC agent 20. It is not limited to. For example,
With the diffusion plate 18 already connected to the array substrate 12, the array substrate 12 and the counter substrate are attached, and then,
The mixed solution may be injected between both substrates. Also, the diffusion plate 1
It is also possible to drop the mixed solution on the array substrate 12 in a state where 8 is connected to the array substrate 12 in advance and then bond the array substrate 12 and the counter substrate together.

Further, the diffusion plate 18 is formed on the counter substrate 11 and the O
You may connect through the C agent 20. If the diffuser plate 18 is in a completely diffused state, light leakage as shown in FIG. 5 does not occur. Further, the diffusion plate 18 may be connected to both the counter substrate 11 and the array substrate 12, and UV light may be irradiated from both the array substrate 12 and the counter substrate 11.

Further, as shown in (FIG. 8), the diffusion plate 18 may be arranged obliquely with respect to the panel 10. Panel 10
An OC agent 20 is filled in the space between the diffusion plate 18 and the diffusion plate 18. With the configuration as shown in FIG. 8, the light becomes like the light 19c, the number of light components proceeding perpendicularly to the normal line of the array substrate 12 increases, and the amount of light incident under the BM 16 increases. Further, as shown in (FIG. 9), the lower portion filled with the OC agent 20 (FIG. 8) may be replaced with a transparent prism 91. Prism 91
The diffusion plate 18, the prism 91 and the array substrate 12 are OC.
It goes without saying that the agents 20c and 20d are used to optically bond.

As described above, the technical idea of the present invention is to scatter UV light by the diffusion plate 18 or the like to cause the diffused light to be incident on the liquid crystal layer 13 of the liquid crystal panel to cure the UV resin under the BM 16. .

Further, although the UV resin is used as the polymer 62, it is not limited to this and may be a photocurable resin. For example, resins that are polymerized by light in the visible light region are sold by many manufacturers.

In the examples, the average particle size of the water-drop liquid crystal has been mainly described, but it goes without saying that the average particle size may be replaced with the average pore size of the polymer network.

Hereinafter, the present invention will be described in more detail with reference to specific examples. Example 1 An array substrate having pixel electrodes formed thereon and a counter substrate having BM and a counter electrode (ITO) formed thereon are bonded so that their electrode surfaces face each other. A UV resin in which glass fibers having a diameter of 13 μm are dispersed is used as a spacer.

Next, as shown in (FIG. 1), the array substrate 1
Opal glass as the diffuser plate 18 was attached to No. 2.
Ethylene glycol was used as the OC agent.

Next, as a PD liquid crystal material, a mixed solution having the materials shown in (Table 1) and a weight ratio was prepared.

[0059]

[Table 1]

The nematic-isotropic phase transition temperature of the mixed solution shown in (Table 1) is METTLER FP900.
As a result of measurement using a thermal analysis system, it was 30.5 ° C.

Subsequently, the mixed solution was injected into the empty cell (hereinafter, the empty cell after the injection is described as a liquid crystal panel).

Next, the liquid crystal panel is placed on a heater plate and heated, and thereafter, an ultrahigh pressure mercury lamp is used as a light source at a temperature of 50 ° C., and the mixed solution is irradiated with ultraviolet rays (irradiation on the substrate surface) from the diffusion plate 18 side. Intensity: 80 mW / cm ² ) was irradiated for 150 seconds to complete a liquid crystal panel made of polymer dispersed liquid crystal. The liquid crystal panel thus completed showed a uniform opaque state over the entire display area in the absence of an electric field, and a uniform transmission state without unevenness was obtained by applying an electric field. When the counter substrate 16 was peeled off and observed, almost no uncured portion existed.

Example 2 As a polymer dispersed liquid crystal material,
A liquid crystal panel made of polymer-dispersed liquid crystal was completed by the same operation as described in Example 1 using the mixed solution having the materials and weight ratios shown in (Table 2).

The nematic-isotropic phase transition temperature of the mixed solution shown in (Table 2) is METTLER FP900.
As a result of measurement using a thermal analysis system, it was 27.3 ° C.

Next, as in the previous case, the plate was placed on a heater plate and heated, and UV light was irradiated at 40 ° C. to cause phase separation. The completed liquid crystal panel showed a uniform white opaque state over the front surface of the display region in the absence of an electric field, and a uniform transmission state without unevenness was obtained by applying an electric field. Further, when the counter substrate 16 was peeled off and observed, there was no uncured portion.

[0066]

[Table 2]

Example 3 As a polymer dispersed liquid crystal material,
A liquid crystal panel made of polymer-dispersed liquid crystal was completed by the same operation as described in Example 1 using the mixed solution having the materials and weight ratios shown in (Table 3).

[0068]

[Table 3]

The nematic-isotropic phase transition temperature of the mixed solution shown in (Table 3) is METTLER FP900.
As a result of measurement using a thermal analysis system, it was 45.5 ° C. The completed liquid crystal panel showed a uniform white opaque state over the front surface of the display region in the absence of an electric field, and a uniform transmission state without unevenness was obtained by applying an electric field.

Example 4 As a polymer dispersed liquid crystal material,
A liquid crystal panel made of polymer-dispersed liquid crystal was completed by the same operation as described in Example 1 using the mixed solution having the materials and weight ratios shown in (Table 4).

The nematic-isotropic phase transition temperature of the mixed solution shown in (Table 4) is METTLER FP900.
As a result of measurement using a thermal analysis system, it was 9.6 ° C.

Next, as in the previous case, the substrate was heated on a heater plate and heated at 25 ° C. with UV light (irradiation intensity on the substrate surface: 80 mW /
cm ² ) for 150 seconds to cause phase separation. The completed liquid crystal panel showed a uniform white opaque state over the front surface of the display region in the absence of an electric field, and a uniform transmission state without unevenness was obtained by applying an electric field. Further, when the counter substrate 16 was peeled off and observed, there was no uncured portion.

[0073]

[Table 4]

[0074]

As described above, according to the method of manufacturing a liquid crystal panel of the present invention, after the mixed solution is injected into the empty cell and the diffuser plate is optically coupled to the empty cell, ultraviolet rays are emitted from the diffuser plate side. Since it irradiates light, it can cure the UV curable resin under the black matrix, the source signal line, or the TFT, and the obtained liquid crystal panel does not peel off on the counter substrate, etc. Is also stable.

Further, since the average particle diameter of the water-drop-shaped liquid crystal around the pixel electrode does not deviate from an appropriate value, light leakage does not occur around the pixel electrode and high contrast display can be realized.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for manufacturing a liquid crystal panel of the present invention.

FIG. 2 is an explanatory diagram of a method for manufacturing a liquid crystal panel according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a conventional liquid crystal panel manufacturing method.

FIG. 4 is an explanatory view of a conventional liquid crystal panel manufacturing method.

FIG. 5 is an explanatory view of a conventional liquid crystal panel manufacturing method.

FIG. 6 is an explanatory diagram of the operation of the polymer dispersed liquid crystal panel.

FIG. 7 is an equivalent circuit diagram of a liquid crystal panel.

FIG. 8 is an explanatory view of a method for manufacturing a liquid crystal panel in another embodiment of the present invention.

FIG. 9 is an explanatory view of a method for manufacturing a liquid crystal panel in another embodiment of the present invention.

[Explanation of symbols]

10 Liquid Crystal Panel 11 Counter Substrate 12 Array Substrate 13 Liquid Crystal Layer 14 Counter Electrode 15 Pixel Electrode 16 Black Matrix 17 Source Signal 18 Diffusion Plate 19, 31a, 31b, 32a, 32b Ultraviolet Light 20, 20a, 20b, 20c, 20d Optical Coupling Layer (O
C agent) 21 Reflector 31 Opening 61 Water-drop liquid crystal 62 Polymer 71 Gate drive IC 72 Source drive IC 73 TFT 74 Additional capacitor 75 One pixel 91 Prism

Claims (14)

[Claims] 1. A first electrode substrate and a second electrode substrate are prepared, and a mixed solution of liquid crystal and uncured photo-curable resin is sandwiched between the first electrode substrate and the second electrode substrate. And a second step of arranging a light diffusing means on the first electrode substrate, and irradiating the mixed solution with light via the light diffusing means,
A third step of curing the resin component of the mixed solution to phase-separate the liquid crystal component and the resin component, and a fourth step of removing the light diffusing means after the third step. Liquid crystal panel manufacturing method. 2. A first electrode substrate and a second electrode substrate are prepared, and a mixed solution of liquid crystal and uncured photocurable resin is sandwiched between the first electrode substrate and the second electrode substrate. A first step of bonding, a light diffusing means to the first electrode substrate through a first optical coupling means, and a light reflecting means to a second optical coupling to the second electrode substrate. A second step of joining via a means, and irradiating the mixed solution with light via the light diffusing means,
A method for producing a liquid crystal panel, which comprises performing a third step of curing the resin component of the mixed solution to phase-separate the liquid crystal component and the resin component. 3. The photocurable resin is an ultraviolet curable resin, and the light is an ultraviolet ray.
A method for manufacturing the liquid crystal panel described. 4. A first substrate on which pixel electrodes are arranged in a matrix and a second substrate on which a counter electrode and a black matrix are formed are prepared, and the first substrate and the second substrate are prepared.
A first step of sandwiching a mixed solution of liquid crystal and an uncured photo-curable resin between the substrates, and a second step of joining a diffusion plate to the first substrate via an optical coupling means. And irradiating the mixed solution with light through the diffusion plate to phase separate the resin component and the liquid crystal component of the mixed solution.
The method of manufacturing a liquid crystal panel, comprising: 5. The optical coupling means is a liquid or a gel, and the optical coupling means has a refractive index of the first or second.
5. The method of manufacturing a liquid crystal panel according to claim 2, wherein the refractive index of the substrate is substantially the same as that of the substrate. 6. The method of manufacturing a liquid crystal panel according to claim 2, wherein the reflecting means is a mirror or a diffusion plate. 7. The liquid crystal panel according to claim 1, wherein in the third step, the mixed solution is heated to bring it into an isotropic state and then irradiated with light. Manufacturing method. 8. The liquid crystal is a nematic liquid crystal, and the photo-curing resin is an ultraviolet-curing resin. When the ordinary refractive index of the liquid crystal is n _o and the refractive index of the cured resin is n _p , n _o and n _The method for manufacturing a liquid crystal panel according to claim 1, 2 or 4, wherein _p and _p are substantially the same. 9. The ratio of liquid crystal in the mixed solution is 50% by weight or more 9
The liquid crystal panel manufacturing method according to claim 1, 2 or 4, wherein the content is 0% by weight or less. 10. The distance between the first substrate and the second substrate is 8 μm.
The method for manufacturing a liquid crystal panel according to claim 1, 2 or 4, wherein the thickness is 25 μm or more. 11. The method of manufacturing a liquid crystal panel according to claim 1, 2, or 4, wherein the light diffusing means is a diffusing plate. 12. The method of manufacturing a liquid crystal panel according to claim 1, 2, or 4, wherein the light diffusing means is a diffraction grating plate. 13. The method of manufacturing a liquid crystal panel according to claim 1, wherein the light diffusing means is a gel in which a diffusing agent is dispersed. 14. The method of manufacturing a liquid crystal panel according to claim 2, wherein the optical coupling means has a refractive index of 1.3 or more.