JPH09292602A - Production of liquid crystal display panel and producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a liquid crystal display panel which has improved scattering performance in a light-scattering state and gives high contrast and little variance in the display quality. SOLUTION: In the production process of a polymer dispersion type liquid crystal display panel, the panel is irradiated with such UV rays in such a manner that the intensity and intensity ratio of 403nm wavelength UV rays to the intensity of 365nm wavelength UV rays are controlled so as to increase the scattering performance. The polymer dispersion type liquid crystal display panel is completed by using a UV irradiation device equipped with at least two UV lamps 21a, 21b each independently having a light-controlling function. This device has at least two kinds of UV light sources having different wavelength distribution from each other produced by selecting different kinds of UV lamps or using optical filters 28, 29 having different wavelength distributions of transmittance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a liquid crystal display panel in which a polymer dispersed liquid crystal in which a liquid crystal is dispersed and held in a polymer matrix is sandwiched between a pair of electrode substrates. Is.

[0002]

2. Description of the Related Art In recent years, as a new display method other than the conventional TN (twist nematic) method, a polymer dispersion type liquid crystal display panel which does not use a polarizing plate has been attracting attention.

In this system, a polymer-dispersed liquid crystal in which a nematic liquid crystal is dispersed and held in a polymer having the same refractive index as that of the liquid crystal is sandwiched between a pair of upper and lower transparent electrode substrates, and the liquid crystal is changed depending on the presence or absence of an electric field. By controlling the apparent refractive index, light scattering state (white turbid state) and transmission state (transparent state) are created, and
It is to switch between N and OFF.
1631 and JP-A-1-198725).

8A and 8B are schematic views showing the display principle of this liquid crystal display panel. As shown in (a) of FIG. 8, since the molecular axes of the liquid crystal molecules 84 are oriented in random directions when no voltage is applied, the refractive index of the liquid crystal region is different from that of the surrounding polymer matrix 85. , Scattering occurs at the interface between the liquid crystal region and the polymer matrix. That is,
Light 82 incident on the liquid crystal display panel becomes scattered light 83,
As a result, a scattering state is obtained.

As shown in FIG. 8 (b), when an AC voltage 87 is applied to the electrode 81, the molecular axes of the liquid crystal molecules 84 are aligned in the direction of the electric field, and the liquid crystal region of the liquid crystal region with respect to the light incident perpendicularly on the substrate. Since the refractive index is almost the same as the refractive index of the surrounding polymer matrix 85, light scattering does not occur and the transmitted light 86 is obtained.
As a result, a transmission state is obtained.

In the liquid crystal display panel using this polymer-dispersed liquid crystal, since light scattering is used for the ON and OFF shutters, it is not necessary to use a polarizing plate, and compared with the conventional TN type liquid crystal display panel. A bright display more than twice as bright is obtained.

Further, in the conventional TN type liquid crystal display panel,
Since it is necessary to control the alignment process with high accuracy and the gap between the upper and lower electrode substrates accurately, there is a problem that display unevenness is likely to occur in large area display, but liquid crystal display using polymer dispersed liquid crystal The panel has a feature that a large-area cell can be easily manufactured because the alignment treatment is not required and the gap between the electrode substrates is not strictly controlled.

[0008]

Generally, in a liquid crystal display panel using a polymer dispersed liquid crystal, it is necessary to have a high scattering state in order to realize high contrast. For that purpose, it is necessary to increase the difference between the refractive index of the liquid crystal material and the refractive index of the surrounding polymer matrix, and it is conceivable to use a cyano liquid crystal material having a high refractive index as the liquid crystal material.

However, the cyano liquid crystal material is generally poor in reliability against heat and light, and particularly when this liquid crystal material is used in an active matrix type liquid crystal display panel, sufficient voltage holding characteristics cannot be obtained and good display performance can be obtained. Absent.

In recent years, application of a fluorine-based liquid crystal material having excellent reliability has been studied to solve this problem, and improvement of response speed and improvement of reliability have been reported. However, a fluorine-based liquid crystal material generally has a low refractive index, and has a problem that the contrast is low as compared with a liquid crystal display panel using a cyano liquid crystal material.

Another major factor related to the scattering performance of a liquid crystal display panel using a polymer-dispersed liquid crystal is the droplet diameter of the liquid crystal region. If the gap between the electrodes of the cells is constant, and the droplet size in the liquid crystal region is too large, the number of droplets present in the gap between the cells decreases, and
Since the number of scatterings at the interface of the polymer matrix is reduced, the scattering performance is deteriorated. On the contrary, if the droplet diameter of the liquid crystal region is too smaller than the wavelength of light, the number of droplets existing in the gap between the cells increases, but scattering is less likely to occur at the liquid crystal phase / polymer matrix interface. After all, the scattering performance becomes worse.

Conventionally, the polymerization initiation temperature or the ratio of the liquid crystal to the polymerizable material was changed in order to control the size of the droplet diameter of the liquid crystal region. From the viewpoint of the compatibility of the polymerizable material (the temperature at which the nematic phase begins to emerge from the isotropic phase), it was difficult to stably control the particle size under temperature conditions that facilitate production.

The present invention solves the problems of the conventional polymer-dispersed liquid crystal, stably improves the scattering performance in the light-scattering state under a temperature condition that is easy to manufacture, and obtains a high contrast without characteristic variations. It is an object of the present invention to provide a manufacturing method and a manufacturing apparatus for a liquid crystal display panel.

[0014]

The cleavage reaction of a polymerization initiator is controlled in order to control the size of the droplet diameter of the liquid crystal region of a liquid crystal display panel using a polymer dispersed liquid crystal. That is, it is necessary to irradiate with ultraviolet rays having wavelengths respectively corresponding to the absorption wavelength ranges of the chemical components contained in the commercially available polymerization initiator. Further, it is necessary to optimize not only the wavelength of the irradiation ultraviolet ray but also the intensity of each, in other words, the intensity ratio of each wavelength to the intensity of the reference wavelength.

In the method for producing a liquid crystal display panel according to claim 1 of the present invention, in the ultraviolet polymerization step of the polymerizable material of the liquid crystal display panel using the polymer dispersed liquid crystal, the ultraviolet intensity of 365 nm at the panel reaching surface is 40 nm. mW / cm ² or more and 403 nm for an ultraviolet intensity of 365 nm
The method for producing a liquid crystal display panel according to claims 2 and 3 of the present invention is characterized by irradiating an ultraviolet ray having a ratio of ultraviolet intensity of 0.4 to 0.6 adjusted. In the ultraviolet polymerization process of the polymerizable material of the liquid crystal display panel using the dispersed liquid crystal, at least two kinds of optical filters having different cutoff wavelengths are arranged between the ultraviolet lamp and the liquid crystal display panel to irradiate the ultraviolet rays. A method for producing a liquid crystal display panel, wherein the method for producing a liquid crystal display panel according to claims 4 to 7 of the present invention is the ultraviolet polymerization step of a polymerizable material of a liquid crystal display panel using a polymer dispersed liquid crystal. A method for manufacturing a liquid crystal display panel is characterized in that at least two kinds of ultraviolet light sources having different wavelength distributions are simultaneously irradiated with ultraviolet light.

Further, in the liquid crystal display panel manufacturing apparatus according to claims 8 and 9, at least two kinds of ultraviolet rays having different wavelength distributions are used in the ultraviolet ray polymerization step of the polymerizable material of the liquid crystal display panel using the polymer dispersed liquid crystal. It is an ultraviolet irradiation device characterized by irradiating ultraviolet rays simultaneously from a light source.

In the present invention, after a mixed composition of a liquid crystal and an ultraviolet curable polymerizable material is sandwiched between a pair of electrode substrates,
Ultraviolet rays are irradiated to form liquid crystal droplets by optical phase separation, and a small amount of a polymerization initiator is dissolved in the mixed composition to start an ultraviolet polymerization reaction.

FIG. 7 shows 2-hydroxy-2-methyl-1-phenyl-propan-1-one (alias name) contained in "Darocur 4265 (manufactured by Ciba-Geigy Co., Ltd.)" which is a typical radical polymerization initiator. : Darocur 1173, manufactured by Ciba-Geigy Co., Ltd. and 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide (alias: Lucillin TP)
It is a figure which shows the wavelength dependence characteristic of the molar extinction coefficient of O, the BASF Corporation make). The polymerization initiator components "Darocure 1173" and "Lucirin TPO" in "Darocure 4265" correspond to the peak wavelengths of 365 nm and 403 nm of the ultra-high pressure mercury lamp (eg, CHM-3000 manufactured by Oak Co., Ltd.). However, in “Darocur 4265” there is “Darocur 1173
And 50% by weight of “Lucillin TPO” are included. At the very early stage of the polymerization reaction by ultraviolet rays, the polymerization proceeds even with “Darocur 1173”, but when the liquid crystal phase-separates, scattering occurs and In particular, the light on the single wavelength side is less likely to enter the inside of the polymer-dispersed liquid crystal layer, and the curing of the incident side surface proceeds rapidly, but the curing speed on the inside and the exit side is relatively slow compared to the surface. As a result, the droplet diameter is different between the vicinity of the incident side surface and other portions, which causes deterioration of scattering performance and characteristic variation due to variation in droplet diameter.

Therefore, the polymerization initiator of the liquid crystal display panel using the polymer-dispersed liquid crystal has a large molecular weight at 403 nm in order to sufficiently transmit the ultraviolet light having a wavelength longer than 365 nm to the deep portion of the polymer-dispersed liquid crystal layer. The use of "Darocur 4265" containing an equal amount of "Lucillin TPO" having an extinction coefficient is suitable.

However, even if "Darocure 1173" and "Lucirin TPO" are in equal amounts, the intensity of 365 nm and 403 nm of the ultra-high pressure mercury lamp to be irradiated is not sufficient, or conversely too strong, or of 365 nm and 403 nm. If the intensity balance is not appropriate, the droplet size will be different near the UV incident surface and other areas,
This causes deterioration of scattering performance and characteristic variations due to variations in droplet size.

The intensity and balance (intensity ratio) of the irradiated ultraviolet rays can be achieved by using a filter, but it is difficult to achieve a predetermined intensity ratio with one sheet, and at least 2
Use a combination of filters. In this case, in order to prevent the one filter from decomposing the liquid crystal-polymer material mixture by light in the short wavelength range of ultraviolet rays, it is desirable to use a UV cut filter having a cutoff characteristic near 350 nm, for example.

In addition, in one ultraviolet irradiation device, 365
Achieving a prescribed intensity and intensity ratio for the irradiated ultraviolet light by installing at least two types of ultraviolet light sources with different intensity ratios of nm and 403 nm and irradiating the cells filled with the liquid crystal-polymer material mixture with the ultraviolet light at the same time. You can At this time, at least two types of ultraviolet light sources having different intensity ratios of 365 nm and 403 nm may use at least two types of ultraviolet lamps having different intensity ratios of 365 nm and 403 nm, and two ultraviolet rays having the same intensity ratio of 365 nm and 403 nm may be used. It is also possible to use a lamp and install filters near the lamp having different transmission wavelength distributions for dimming.

[0023]

FIG. 1 is a block diagram showing an embodiment of the present invention.
From now on, it will be specifically explained based on FIG. [Example 1] A pair of transparent glass substrates provided with transparent electrodes made of an indium / tin oxide film were prepared and washed at 110 ° C.
After drying for 30 minutes, spin-coat "Polyimide resin film RN-747 (Nissan Chemical Co., Ltd.)" at 2000 rpm for 60 seconds and cure at 200 ° C for 1 hour. A thermosetting sealant (StructBond: Mitsui Toatsu Kagaku Co., Ltd.) was provided through a spacer (Micropearl: Sekisui Fine Co., Ltd.) to form a liquid crystal injection port, which was then bonded and heated at 150 ° C. for 4 hours. The sealing material was completely cured to obtain an empty cell.

Next, 8.000 g of nematic liquid crystal "TL-205 (manufactured by Merck Ltd.)" is used as a liquid crystal material, and "2-ethylhexyl acrylate" is used as a polymer forming monomer.
1.800 g, 0.180 g of "polyurethane acrylate" as an oligomer, "Darocur 117 as a photopolymerization initiator"
0.020 g of "3 (manufactured by Merck &Co.)" was prepared and sufficiently stirred at 40 ° C to prepare a uniform mixed solution of polymer and liquid crystal.

This homogeneous mixed solution was injected into the empty cell previously heated on a hot plate at 40 ° C. from the liquid crystal injection port, and the injection port was sealed. FIG. 1 shows a liquid crystal display panel manufacturing apparatus of the present invention.

This liquid crystal display panel manufacturing apparatus uses circulating water 1
Above the water jacket plate 16 the temperature of which is adjusted to 40 ° C. by the first and second optical filters 12 and 1,
3 is arranged, and an ultra-high pressure mercury lamp 11 (CHM-3000, manufactured by Oak Co.) is arranged above it as an ultraviolet lamp. A power supply device for adjusting the amount of light is connected to the extra-high pressure mercury lamp 11. Reference numeral 17 is a lamp hood.

A liquid crystal cell 14 in which liquid crystal is injected and the injection port is sealed is placed on a water jacket plate 16 and irradiated with ultraviolet rays at a predetermined intensity for 90 seconds to form a liquid crystal consisting of a series of polymer-dispersed liquid crystals. A display panel was produced.

First, two sheets of glass for photographic dry plates are placed as the first and second filters 12 and 13, and ultraviolet rays of 90 to 90 mW / cm ² are placed on the above ultraviolet irradiation device.
Second irradiation was performed to produce a liquid crystal display panel made of polymer-dispersed liquid crystal (hereinafter, referred to as liquid crystal display panel A group).

Various types of filters are placed as the first and second filters 12 and 13, and the polymer-dispersed liquid crystal is irradiated on the above-mentioned ultraviolet irradiation device at an intensity of 50 mW / cm ² for 90 seconds. A liquid crystal display panel was prepared (hereinafter referred to as liquid crystal display panel B group).

Further, the first filter 12 is 350 n
Using a UV cut filter "UV-35" (manufactured by Toshiba Corp.) that cuts ultraviolet rays having a wavelength of m or less, a liquid crystal display panel made of polymer-dispersed liquid crystal was produced in the same manner as above (hereinafter, liquid crystal display Panel C group). UV used
Fig. 6 shows the transmittance characteristic curve of the cut filter "UV-35".
Shown in

With respect to the liquid crystal cell thus completed, the optical modulation performance in the direction perpendicular to the cell was measured by using an optical evaluation device for liquid crystal cell "LCD-7000" (manufactured by Otsuka Electronics Co., Ltd.) and a square wave having a frequency of 30 Hz. , And the acceptance angle of 2.8
The measurement was carried out at a measurement temperature of 30 ° C. Assuming that the light transmittance when no voltage is applied is T ₀ (%), the liquid crystal display panel A group has T
₀ = 0.6 to 2.1%.

FIG. 4 shows the dependence of the light transmittance T _{0 on} the ultraviolet intensity of the liquid crystal display panel of group A. In the measurement by the above optical system, it can be said that when T ₀ is 1% or less, the liquid crystal cell has sufficient scattering performance. Therefore, in this configuration, when the ultraviolet intensity of 40 mW / cm ² or more is used, sufficient scattering performance is obtained. A liquid crystal display panel comprising the polymer-dispersed liquid crystal thus obtained was obtained.

FIG. 5 shows the liquid crystal display panel B group with the light transmittance on the vertical axis and 403 nm for an ultraviolet intensity of 365 nm.
An ultraviolet intensity ratio characteristic diagram of T _{0 in} which the horizontal axis represents the ratio of the ultraviolet intensity of As shown in this figure, the ratio of the 403 nm UV intensity to the 365 nm UV intensity has an optimum range that reflects the wavelength distribution of the molar extinction coefficients of "Darocur 1173" and "Lucirin TPO". In order to realize sufficient scattering performance, the condition that the light transmittance T ₀ is 1% or less, that is, 403 nm with respect to the ultraviolet intensity of 365 nm
The ratio of the UV intensities was 0.4 to 0.6.

Next, the charge retention characteristics (voltage retention rate) of the above liquid crystal cell were measured. The charge retention characteristics are
A voltage holding characteristic when a square wave pulse having a frame frequency of 30 Hz, a voltage of 5 V and an ON time of 60 μs was applied to the liquid crystal cell was evaluated as an index (the measuring method is, for example, JP-A-7-56153).

The voltage holding characteristics were measured at 60 ° C. for each liquid crystal cell. As a result, the liquid crystal cell of the liquid crystal display panel A group had 60 to 70%, and the liquid crystal cell of the liquid crystal display panel B group had a difference of about 65% depending on the filter. It was 90% in the liquid crystal cell of the liquid crystal display panel C group.

[Example 2] A pair of transparent glass substrates provided with transparent electrodes made of an indium / tin oxide film were prepared, washed, and then dried at 110 ° C for 30 minutes to obtain a polyimide resin film "RN".
-747 "(Nissan Chemical Co., Ltd.) was spin-coated at 2000 rpm for 60 seconds and cured at 200 ° C for 1 hour.
μm diameter plastic spacer (Micropearl:
Through Sekisui Fine Co., Ltd., a thermosetting sealant (StructBond: Mitsui Toatsu Kagaku Co., Ltd.) was used to attach and bond the liquid crystal, and heated at 150 ° C for 4 hours to completely cure the sealant. To obtain an empty cell.

Next, 8.000 g of nematic liquid crystal "TL-205" (manufactured by Merck) as a liquid crystal material and "2-ethylhexyl acrylate" as a polymer forming monomer.
1.800 g, 0.180 g of "polyurethane acrylate" as an oligomer, "Darocur 117 as a photopolymerization initiator"
0.020 g of "3 (manufactured by Merck &Co.)" was prepared and sufficiently stirred at 40 ° C to prepare a uniform mixed solution of polymer and liquid crystal.

This homogeneous mixed solution was injected into the empty cell previously heated on a hot plate at 40 ° C. from the liquid crystal injection port, and the injection port was sealed. FIG. 2 shows an apparatus for manufacturing a liquid crystal display panel according to the present invention.

Above the ultraviolet irradiator, first and second ultra-high pressure mercury lamps 21a and 21b of the same type and having the same wavelength distribution as an ultraviolet lamp (CHM-3000 manufactured by Oak Co., Ltd.) are provided.
) Is attached, and a power supply device for adjusting the light amount of each is independently connected. Optical filters 28 and 29 are attached to the lower portions of the first and second ultra-high pressure mercury lamps 21a and 21b, respectively, and all the light emitted from the respective ultra-high pressure mercury lamps passes through this filter and is irradiated. It has become so. 27 is a lamp hood.

Specifically, a glass filter is used as the filter 28, and "UV-3" is used as the filter 29.
5 "is used by stacking two sheets, and the filter 28 and the filter 2 are used.
9 has different transmittance characteristics and the light passing through the filter is 365
The ratio of the 403 nm UV intensity to the nm UV intensity is
On the basis of 0.5, an irradiation source having a richer light amount of 365 nm and an irradiation source having a richer light amount of 403 nm were prepared.

At the bottom of the ultraviolet irradiation device, a water jacket plate 2 whose temperature is adjusted to 40 ° C. by circulating water 25
6 are arranged. The liquid crystal cell 24 in which the liquid crystal is injected and the injection port is sealed is attached to the water jacket plate plate portion 26.
Place it on a glass plate and put it through a UV cut filter (UV-35, manufactured by Toshiba Corp.) 22 at a strength of 50 mW / cm ^{2 to} emit 9
Irradiation was carried out for 0 seconds to prepare a liquid crystal display panel made of polymer dispersed liquid crystal. At this time, each of the ultra-high pressure mercury lamps 21a and 21b
The current supplied to was adjusted so that the ratio of the 403 nm UV intensity to the 365 nm UV intensity was 0.5.

With respect to the liquid crystal cell completed in this way, the optical modulation performance in the direction perpendicular to the cell was measured using a liquid crystal cell optical evaluation device "LCD-7000" (manufactured by Otsuka Electronics Co., Ltd.) to generate a square wave with a frequency of 30 Hz. Apply and receive angle 2.8
The measurement was carried out at a measurement temperature of 30 ° C. Letting T ₀ (%) be the light transmittance with no voltage applied, T ₀ = 0.7%.

Next, the charge retention characteristics (voltage retention rate) of the above liquid crystal cell were measured. The charge retention characteristics were evaluated by using the voltage retention characteristics when a square wave pulse having a frame frequency of 30 Hz, a voltage of 5 V and an ON time of 60 μs was applied to a liquid crystal cell as an index (for the measuring method, see, for example, Japanese Patent Laid-Open No. 7- 56153). Holds voltage at 60 ℃
It was 90% when measured by.

When the apparatus of FIG. 2 was operated for several hundred hours, a change in the wavelength distribution of the ultraviolet intensity was observed mainly due to the deterioration of the ultra-high pressure mercury lamp and the UV filter. , 21b, by adjusting the current supplied to the
The ultraviolet intensity ratio of m could be maintained at 0.5.

[Example 3] A pair of transparent glass substrates provided with transparent electrodes made of an indium / tin oxide film were prepared, washed, and then dried at 110 ° C for 30 minutes to obtain a polyimide resin film "RN".
-747 (Nissan Chemical Co., Ltd.) "was applied at a spin rate of 2000 rpm for 60 seconds and cured at 200 ° C for 1 hour.
μm diameter plastic spacer (Micropearl:
Through Sekisui Fine Co., Ltd., a thermosetting sealant (StructBond: Mitsui Toatsu Kagaku Co., Ltd.) was used to attach and bond the liquid crystal, and heated at 150 ° C for 4 hours to completely cure the sealant. To obtain an empty cell.

Next, 8.000 g of nematic liquid crystal "TL-205 (manufactured by Merck &Co.)" is used as a liquid crystal material, and "2-ethylhexyl acrylate" is used as a polymer forming monomer.
1.800 g, 0.1800 g of "polyurethane acrylate" as an oligomer, and "Darocure 1" as a photopolymerization initiator.
173 (manufactured by Merck & Co.) "was prepared and sufficiently stirred at 40 ° C to prepare a uniform mixed solution of polymer and liquid crystal.

This homogeneous mixed solution was injected into the empty cell previously heated on a hot plate at 40 ° C. from the liquid crystal injection port, and the injection port was sealed. FIG. 3 shows a liquid crystal display panel manufacturing apparatus of the present invention.

Ultra-high pressure mercury lamps 31, 32 having different wavelength distributions as an ultraviolet lamp are provided above the ultraviolet irradiation device.
Are attached, and power supply devices for adjusting the respective light amounts are independently connected. Each ultra-high pressure mercury lamp consists of an ultra-high pressure mercury lamp 31 with a richer light quantity of 365 nm and an ultra-high pressure mercury lamp 31 with a richer light quantity of 403 nm, based on a ratio of the ultraviolet light intensity of 403 nm to the ultraviolet light intensity of 365 nm of 0.5. There is. 37 is a lamp hood.

At the bottom of the ultraviolet irradiation device, a water jacket plate 3 whose temperature is adjusted to 40 ° C. by circulating water 35
6 are arranged. Liquid crystal is injected, the liquid crystal cell 34 with the injection port sealed is placed on the water jacket plate 36, and U
Ultraviolet rays were irradiated for 90 seconds at an intensity of 50 mW / cm ² through a V cut filter (UV-35, manufactured by Toshiba Corp.) 33 to prepare a liquid crystal display panel made of polymer dispersed liquid crystal. At this time, the current supplied to each of the ultra-high pressure mercury lamps 31 and 32 was adjusted so that the ratio of the 403 nm ultraviolet intensity to the 365 nm ultraviolet intensity was 0.5.

With respect to the liquid crystal cell thus completed, the optical modulation performance in the direction perpendicular to the cell was measured using a liquid crystal cell optical evaluation device "LCD-7000" (manufactured by Otsuka Electronics Co., Ltd.) to generate a square wave with a frequency of 30 Hz. Apply and receive angle 2.8
The measurement was carried out at a measurement temperature of 30 ° C. Letting T ₀ (%) be the light transmittance with no voltage applied, T ₀ = 0.7%.

Next, the charge retention characteristics (voltage retention rate) of the above liquid crystal cell were measured. The charge retention characteristics are
A voltage holding characteristic when a square wave pulse having a frame frequency of 30 Hz, a voltage of 5 V and an ON time of 60 μs was applied to the liquid crystal cell was evaluated as an index (the measuring method is, for example, JP-A-7-56153). Set the voltage holding characteristic to 60
It was 90% when measured at ° C.

Further, when the apparatus of FIG. 3 was operated for several hundred hours, changes in the wavelength distribution of the ultraviolet intensity were observed mainly due to the deterioration of each ultra-high pressure mercury lamp.
Easy by adjusting the current supplied to 1, 32
The ratio of the 403 nm UV intensity to the 365 nm UV intensity could be maintained at 0.5.

In [Example 1] and [Example 2], two optical filters were used to obtain a predetermined transmittance distribution, but three or more optical filters were used. The same effect can be obtained even if the configuration is such that a predetermined transmittance distribution is obtained.

[Embodiment 2] In the embodiment of [Embodiment 3], 2
Although the two ultraviolet lamps are used, the same effect can be expected by using three or more ultraviolet lamps in order to increase the ultraviolet intensity or the ultraviolet intensity ratio.

[0055]

As described above, according to the method for producing a liquid crystal display panel of the present invention, a polymer dispersion type liquid crystal display panel can be produced stably under a temperature condition that is easy to produce, and the scattering performance in a light scattering state is improved. It is possible to produce a high-contrast polymer-dispersed liquid crystal display panel without characteristic variations.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a manufacturing apparatus used for carrying out a method for manufacturing a liquid crystal display panel of the present invention.

FIG. 2 is a configuration diagram of another manufacturing apparatus used for carrying out the method for manufacturing a liquid crystal display panel of the present invention.

FIG. 3 is a block diagram of another manufacturing apparatus used for carrying out the method for manufacturing a liquid crystal display panel of the present invention.

FIG. 4 is a transmittance-irradiated ultraviolet intensity characteristic diagram of the liquid crystal display panel of the example.

FIG. 5 is a ratio characteristic diagram of the transmittance of the panel of Example-the ultraviolet intensity of 403 nm to the ultraviolet intensity of 365 nm.

FIG. 6 is a transmittance-wavelength characteristic diagram of the UV cut filter and glass filter used.

FIG. 7: Wavelength distribution chart of molar extinction coefficient of polymerization initiators “Darocur 1173” and “Lucirin TPO”

FIG. 8 is a schematic view of a display principle of a liquid crystal display panel using polymer dispersed liquid crystal.

[Explanation of symbols]

11 Ultra-high pressure mercury lamp (ultraviolet lamp) 12, 13 First and second filters 14 Liquid crystal cell 15 Circulating water 16 Water jacket plate 17 Lamp hood 21a, 21b First and second ultra-high pressure mercury lamp (ultraviolet lamp) 22 UV cut Filter 24 Liquid crystal cell 25 Circulating water 26 Water jacket plate 27 Lamp hood 28 Filter 29 Filter 31, 32 Super high pressure mercury lamp (ultraviolet lamp) 33 UV cut filter 34 Liquid crystal cell 35 Circulating water 36 Water jacket plate 37 Lamp hood

Claims (9)

[Claims] 1. A maximum value of the molar extinction coefficient of the liquid crystal and the photopolymerization initiator is almost between two substrates, at least one of which is transparent.
After sandwiching a mixture composed of a polymerizable material containing at least two kinds of photopolymerization initiators having a wavelength of 365 nm and approximately 400 nm, the mixture is irradiated with ultraviolet rays to polymerize the polymerizable material, whereby liquid crystals are formed in the continuous polymer matrix. When manufacturing a liquid crystal display panel that is dispersed and held, the irradiation of the above-mentioned ultraviolet rays has an intensity of ultraviolet rays of 365 nm of 40 nm on the panel arrival surface.
A method for producing a liquid crystal display panel, which comprises irradiating ultraviolet rays having a mW / cm ² or more and having a ratio of an ultraviolet intensity of 403 nm to an ultraviolet intensity of 365 nm adjusted to 0.4 to 0.6. 2. The maximum value of the molar extinction coefficient of the liquid crystal and the photopolymerization initiator is almost between the two substrates, at least one of which is transparent.
After sandwiching a mixture composed of a polymerizable material containing at least two kinds of photopolymerization initiators having a wavelength of 365 nm and approximately 400 nm, the mixture is irradiated with ultraviolet rays to polymerize the polymerizable material, whereby liquid crystals are formed in the continuous polymer matrix. In manufacturing a liquid crystal display panel held in a dispersed state, at least two kinds of optical filters having different cutoff wavelengths are arranged between an ultraviolet lamp and the liquid crystal display panel to irradiate ultraviolet rays. Production method. 3. The method for manufacturing a liquid crystal display panel according to claim 2, wherein at least one optical filter is an ultraviolet cut filter having a cutoff wavelength of 365 nm or less. 4. A mixture of a liquid crystal and a polymerizable material is sandwiched between two substrates, at least one of which is transparent,
When producing a liquid crystal display panel in which a liquid crystal is dispersed and held in a continuous polymer matrix by irradiating with ultraviolet light and polymerizing the polymerizable material, the irradiation with the ultraviolet light is:
A method of manufacturing a liquid crystal display panel, which comprises simultaneously irradiating ultraviolet rays with at least two kinds of ultraviolet light sources having different wavelength distributions. 5. The method of manufacturing a liquid crystal display panel according to claim 4, wherein the two kinds of ultraviolet light sources having different wavelength distributions are two kinds of ultraviolet lamps having different wavelength distributions. 6. The liquid crystal display panel according to claim 4, wherein the two kinds of ultraviolet light sources having different wavelength distributions are a combination of two kinds of optical filters having different transmission wavelength distributions and an ultraviolet lamp having the same wavelength distribution. Production method. 7. The method of manufacturing a liquid crystal display panel according to claim 5, wherein each of the ultraviolet lamps has a light control function. 8. An ultraviolet irradiation device having at least two ultraviolet lamps each independently having a dimming function, wherein the ultraviolet lamps have different wavelength distributions. 9. An optical filter having at least two ultraviolet lamps each independently having a dimming function, and an optical filter having a different wavelength distribution of transmittance is provided between each of said ultraviolet lamps and an object to be irradiated. UV irradiation device.