JP2002131732A - Polymer dispersion type liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer dispersion type liquid crystal display device of high display quality excellent in the threshold characteristics and scattering characteristics, to obtain a polymer dispersion type liquid crystal display device with sharp threshold characteristics and to make the single matrix driving possible. SOLUTION: The liquid crystal device has a composite body of a polymer 13 and liquid crystal drops 14 held between a pair of substrates 11 having transparent electrodes 12 formed inside. The liquid crystal device is manufactured in such a manner that the average angle θp of the liquid crystal molecules in the liquid crystal drops 14 from the direction parallel to the substrates 11 ranges from 17 to 35.5. To satisfy the above relation, the liquid crystal drops are deformed or a magnetic field is applied when the liquid crystal is precipitated and separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer-dispersed liquid crystal display device used for a projection display or the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Liquid crystal display elements, which take advantage of the features of thinness, small size, low voltage drive, and low power consumption, display from watches, calculators, etc., to navigation systems, notebook computers, liquid crystal monitors, data projectors, projection liquid crystal televisions. It is widely used everywhere. Among such display modes of the liquid crystal display element, TN (Twisted) is more widely used than before.
Nematic) liquid crystal element having a structure in which liquid crystal molecules are twisted 90 degrees vertically between two opposing substrates.
It is sandwiched between two polarizing plates. Also, an STN (Super Tw) in which the time-division driving characteristics of the TN method are improved.
Liquid crystal display elements of the ised nematic type are also used in Japanese word processors and the like. further,
Recently, an information device using a ferroelectric liquid crystal, which changes the arrangement state of liquid crystal molecules by spontaneous polarization of the liquid crystal molecules and uses an electro-optic effect accompanying the change in the arrangement state for display, has been put to practical use.

However, since these liquid crystal display elements require at least one polarizing plate, there have been problems that the liquid crystal display is dark, that an alignment treatment is required, and that the cell thickness control is not easy.

On the other hand, for such a liquid crystal display device,
There has been proposed a method in which a polarizing plate is unnecessary, and the arrangement of liquid crystal molecules is controlled by an electric field to create a cloudy state or a transparent state. In this method, when a composite of liquid crystal and a transparent polymer is sandwiched between two substrates, and the liquid crystal molecules have a positive dielectric anisotropy, the ordinary refractive index of the liquid crystal molecules and the refractive index of the transparent polymer are used. When the refractive indices are matched, a voltage is applied to align the long axes of the liquid crystal molecules in parallel with the electric field, and when they match the refractive index of the transparent polymer, the interface becomes transparent because there is no light scattering at the interface, On the other hand, when no voltage is applied, the liquid crystal molecules are oriented in various directions, and the refractive index does not match at the interface with the transparent polymer. is there.

A typical example of this method is NCAP (Ne
magic Curvilineear Aligned
Phase is a nematic liquid crystal microencapsulated with polyvinyl alcohol or the like (powder and industrial, VOL.22, NO.8 (199)
0)). In addition, PDLC (Polymer
Dispersed Liquid Crysta
1), which is a method of dispersing liquid crystal microdroplets in a polymer matrix (Flat Panel Display '91, Nikkei BP, p. 219). Also, PNL
C (Polymer Network Liquid)
Crystal), which has a structure in which the resin spreads in a three-dimensional network in the continuous phase of the liquid crystal (IEICE Technical Report, EID
89-89, p1).

[0006] These composites of liquid crystal and transparent polymer are collectively called polymer dispersed liquid crystal. Therefore, also in this specification, the term “polymer-dispersed liquid crystal” is used as a generic term including the above-mentioned NCAP, PDLC, PNLC, and the like. That is, in this specification, the term "polymer dispersed liquid crystal" is not limited to liquid crystal droplets dispersed in a polymer matrix in the form of islands, but also those in which liquid crystal droplets are continuously connected, and even resin. Having a structure that spreads like a three-dimensional network in a continuous phase of a liquid crystal.

Conventionally, these methods for producing a composite of a liquid crystal and a polymer involve a mixed composition obtained by dissolving a liquid crystal material and an uncured resin monomer such as an acrylic or epoxy ultraviolet curable resin between two substrates. When the resin is injected and irradiated with ultraviolet rays, the resin monomer is polymerized and the liquid crystal and the resin undergo phase separation. As a result, a structure in which a liquid crystal is dispersed in a polymer or a structure in which a polymer spreads in a network in a liquid crystal is obtained (flat panel display '91, Nikkei B
Company P, p219, IEICE Technical Report, EI
D89-89, p1 etc.).

In such a polymer-dispersed liquid crystal, in order to improve the light scattering property of the composite of the liquid crystal and the polymer, the shape of the liquid crystal droplet is flat (the cross-sectional shape of the liquid crystal droplet is perpendicular to the substrate). Japanese Patent Application Laid-Open No. Hei 5 (1999) -122566 describes an example in which the length in the direction is smaller than the length in the direction parallel to the substrate.
-80302 and JP-A-7-181454. That is, Japanese Patent Application Laid-Open No. 5-80302 discloses an example in which liquid crystal droplets are pressed in a heated state to form flat liquid crystal droplets, and the aspect ratio is 1.2 to 5.0.
(Equivalent to 20 to 80 when converted to a deformation rate described later)
Is stated to be desirable. Further, Japanese Patent Laid-Open No. 7-1814
No. 54 discloses an example in which a flat liquid crystal droplet is formed by pressing while irradiating ultraviolet rays, and the thickness of the cross section of the liquid crystal droplet is desirably の of the length. 2-1 /
4 (corresponding to 50 to 75 when converted to a deformation ratio described later).

It is said that by forming the liquid crystal droplets in a flat plate shape as described above, there is an advantage that steepness is high and hysteresis is reduced.

[0010]

However, according to our study, if the flatness of the liquid crystal droplet is changed to 1.2 or more (corresponding to 20 when converted to a deformation ratio described later) as described in the above example, it is rather It has been found that there is a problem in that display characteristics such as a decrease in contrast are deteriorated.

Accordingly, an object of the present invention is to improve the scattering characteristics without impairing the display characteristics, and further to increase the steepness of the amount of transmitted light with respect to the voltage, thereby enabling simple matrix driving.

[0012]

In order to achieve this object, a liquid crystal display device of the present invention comprises a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer, which is disposed between a pair of substrates. Wherein the liquid crystal molecules in the liquid crystal droplets are oriented substantially parallel to the substrate and randomly oriented in a plane parallel to the substrate. It is characterized by. Further, in the liquid crystal display element of the present invention, a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are flattened in a cell thickness direction. The liquid crystal display element is a polymer-dispersed liquid crystal display element that is deformed into a simple structure, wherein the amount of deformation of the liquid crystal droplet is in a range in which liquid crystal molecules do not rise in the cell thickness direction due to the excluded volume effect of liquid crystal. In some cases. Here, the term “the amount of deformation of the liquid crystal droplet” means a ratio of “the difference between the length of the liquid crystal droplet in the substrate parallel direction and the length in the cell thickness direction” to the “length of the liquid crystal droplet in the substrate parallel direction”. .

According to the configuration of the present invention, the object of improving light scattering characteristics is achieved. The reason is described below. In a general polymer-dispersed liquid crystal display device, liquid crystal droplets are spherical. In this case, the orientation of each liquid crystal droplet is random with respect to the substrate, and is random even in a plane parallel to the substrate. Such an alignment state is obtained because the liquid crystal droplet is spherical and has a symmetric shape, so that the direction in which the pole is generated is not regular. With such a conventional liquid crystal orientation, a sufficient light scattering effect cannot be obtained. Therefore, in order to obtain a sufficient light scattering effect, it is considered effective to treat the liquid crystal molecules in the liquid crystal droplet so as to be arranged in parallel to the substrate. This is because scattering is caused by a mismatch in the refractive index difference between the liquid crystal and the polymer, and a mismatch in the refractive index between the liquid crystal droplets. This is because the effective refractive index anisotropy Δn of increases, and as a result, scattering increases. However, even when the liquid crystal molecules are arranged in parallel to the substrate, scattering is small if the directions of the liquid crystal molecules are aligned in a plane parallel to the substrate. This is because a sufficient difference in the refractive index between the liquid crystal droplets is not obtained, so that a sufficient scattering intensity cannot be obtained. Therefore, the most desirable orientation mode of the liquid crystal molecules for improving the scattering effect is that the liquid crystal molecules in the liquid crystal droplets are arranged in parallel to the substrate and are randomly oriented in a plane parallel to the substrate. On the other hand, by flattening the liquid crystal droplets, the liquid crystal molecules can be arranged in parallel to the substrate. This is because when a liquid crystal droplet is deformed into a flat structure that is shrunk in the cell thickness direction, the length of the liquid crystal droplet in the cell thickness direction becomes shorter than the length of the liquid crystal droplet in the direction parallel to the substrate, resulting in an asymmetry. Become. In this case, it was found that the liquid crystal molecules in the liquid crystal droplet were oriented in a direction parallel to the substrate. Therefore, the liquid crystal is oriented so that the bipole axis approaches parallel to the substrate. However, even when contracted in the cell thickness direction, the cross-sectional shape of the liquid crystal droplet parallel to the substrate remains circular and is not deformed. Therefore, since the liquid crystal molecules have symmetry in a plane parallel to the substrate, the liquid crystal molecules have no regularity and are randomly aligned. Therefore, by flattening the liquid crystal droplet, the orientation of the liquid crystal molecules in the liquid crystal droplet becomes parallel to the substrate and random in a plane parallel to the substrate, thereby improving the scattering effect.

It should be noted here that the improvement of the scattering effect is not a direct effect of the deformation of the shape of the liquid crystal droplet, but the orientation of the liquid crystal parallel to the substrate due to the deformation, and the surface parallel to the substrate. This is because it was random within. Therefore, irrespective of the amount of deformation of the liquid crystal droplet, if the liquid crystal droplet is deformed, the scattering effect is not always improved. In this regard, it has been confirmed by the present inventor that excessive deformation causes deterioration of the characteristics. The reason why excessive deformation causes deterioration of the characteristics is that when the deformation increases, the tendency of the liquid crystal molecules to line up in the cell thickness direction (the short axis direction of the liquid crystal droplet) increases due to the excluded volume effect of the liquid crystal. is there. That is, a phenomenon that the liquid crystal molecules rise in the vertical direction rather occurs due to the excluded volume effect of the liquid crystal.

Therefore, the present invention provides a configuration in which a liquid crystal droplet is deformed within a range in which a rising force acting on the liquid crystal molecule due to the excluded volume effect of the liquid crystal does not occur, thereby obtaining the orientation of the liquid crystal molecule in the liquid crystal droplet. Can be made relatively parallel to the substrate. As a result, it is possible to realize a polymer-dispersed liquid crystal display device capable of improving light scattering characteristics without impairing display characteristics such as contrast.

According to the results of experiments conducted by the present inventor on both the case where the anchoring strength is normal and the case where the anchoring strength is strong, the deformation amount of the liquid crystal droplet is 10% or more when the anchoring strength is normal. Then, the phenomenon that the liquid crystal molecules rise in the vertical direction occurs due to the excluded volume effect of the liquid crystal. Therefore, when the anchoring strength is normal, if the amount of deformation of the liquid crystal droplet is set to 10% or less, the orientation direction of the liquid crystal molecules in the liquid crystal droplet can be made relatively close to the substrate. In addition, when the anchoring strength is high, when the deformation amount of the liquid crystal droplet is 20% or more, a phenomenon occurs in which the liquid crystal molecules rise in the vertical direction due to the excluded volume effect of the liquid crystal. Therefore, in the case where the anchoring strength is high, if the deformation amount of the liquid crystal droplet is set to 20% or less, the orientation direction of the liquid crystal molecules in the liquid crystal droplet can be made relatively close to the substrate.

Further, according to the present invention, as a method of expressing the amount of deformation of a liquid crystal droplet, an average value θ of angles formed between liquid crystal molecules and a substrate is used.
In some cases, p is used, the dielectric ratio E is used, or the deformation ratio P is used. This is because the tilt angle of the liquid crystal molecules with respect to the substrate, the dielectric ratio E, and the deformation ratio P change in response to the deformation of the liquid crystal droplet, so that the average value θp, the dielectric ratio E, and the deformation ratio P are changed. This is because the amount of deformation of the liquid crystal droplet can be expressed by using this. As means for deforming the liquid crystal, pressing by a vacuum pack, application of hydrostatic pressure, or the like can be used.

Further, the liquid crystal display device of the present invention is a liquid crystal display device in which the liquid crystal is not deformed in the cell thickness direction, and is configured such that the average value θp of the angle between the liquid crystal molecules of the liquid crystal and the substrate is reduced. It may be. Such a liquid crystal display element can be manufactured by applying a magnetic field between the substrates during the process of separating and separating the liquid crystal, or by imparting a polarizing property to ultraviolet rays. Incidentally, the liquid crystal display element of the present invention,
Since the steepness can be increased, the present invention can be suitably applied not only to a liquid crystal display element driven by an active matrix but also to a liquid crystal display element driven by a simple matrix.

Further, the liquid crystal display device of the present invention is a liquid crystal display device in which a composite of a polymer and a liquid crystal is held between a pair of substrates, wherein the polymer uses a liquid crystal monomer as a polymerizable monomer. It is obtained by a legal method, and is configured such that the azimuth angle in the in-plane direction parallel to the substrate of the liquid crystal is random, and the average value θp of the angle between the liquid crystal molecules of the liquid crystal and the substrate is low. In some cases. Such a liquid crystal display element is obtained by using a liquid crystal monomer as a polymerizable monomer and depositing and separating liquid crystal by polymerization of the monomer by irradiation of ultraviolet rays.

When a liquid crystal monomer is used as such a polymerizable monomer, a mixture of the liquid crystal and the polymerizable monomer shows a uniform liquid crystal phase. Therefore, when the liquid crystal is separated by polymerization of the monomer, an effect is produced in which the liquid crystal is separated and separated without obstructing the liquid crystal phase. Therefore, if the conditions are set so that the molecular orientation state of the mixture showing the liquid crystal phase before polymerization is parallel to the substrate and random within a plane parallel to the substrate, the mixture is precipitated and separated by irradiation with ultraviolet light. Under the influence of the state before the polymerization, the alignment state of the liquid crystal molecules of the liquid crystal is arranged nearly parallel to the substrate and is random in a plane parallel to the substrate.

[0021]

According to the present inventor, according to the present invention, the flatness of a liquid crystal droplet is not made to be 1.2 or more, but the deformation of the liquid crystal droplet is performed, but the flatness is reduced. It has been found that the characteristics are better when the amount is suppressed.

Embodiment 1 Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of the liquid crystal display device of the present invention, and FIG. 2 is a plan view of the liquid crystal display device of the present invention. In the liquid crystal display element shown in FIG. 1, a transparent electrode 12 is formed inside two substrates 11 facing each other, and a polymer 13 is placed between the transparent electrodes 12.
A liquid crystal element in which liquid crystal droplets 14 are dispersed is disposed. The diameter d0 (see FIG. 2) of the liquid crystal droplet 14 was about 1.2 μm. Note that a dichroic dye may be contained in the liquid crystal. In this case, a guest-host type liquid crystal device that absorbs light with the dichroic dye is obtained.

The present invention is characterized in that the liquid crystal droplet 14 is deformed in the cell thickness direction. In the case shown in FIG.
The liquid crystal droplet 14 has a flat structure whose length is reduced in the cell thickness direction. That is, the shape of the liquid crystal droplet 14 is a flat shape in which only the length in the cell thickness direction is reduced, and the cross-sectional shape parallel to the substrate remains circular and is not deformed. Although the arrangement of the liquid crystal molecules is depicted in FIG. 1 as a bipole structure having two poles in the horizontal direction of the drawing, this is intended that the bipole axis is substantially parallel to the substrate, and the bipole axis is It is not intended that they are arranged in one axis direction. Further, in FIG. 1, in order to facilitate understanding of the drawing, the shapes of the liquid crystal droplets are all drawn as uniform shapes. However, actually, the shapes of the liquid crystal droplets are not uniform as shown in FIG. 1. Note that, as shown in FIG. 2, the bipole axes are randomly present in a plane parallel to the substrate.

A method for manufacturing the above liquid crystal display device will be described below with reference to FIG. FIG.
As shown in (a), first, two substrates 11 are bonded to face each other. Note that a transparent electrode 12 is formed inside each substrate 11, and an active matrix substrate on which a TFT transistor is formed is used as one of the substrates.
Note that the distance (cell thickness) d1 between the substrates 11 can be kept constant by, for example, spraying spacers 15 as resin beads having a particle diameter of 12 μm in advance.

Next, as shown in FIG.
In the meantime, a mixture of liquid crystal, polymerizable monomer, oligomer and polymerization initiator is introduced by vacuum injection. At this time, the vacuum injection port (not shown) formed in the seal portion on the side of the liquid crystal panel is not sealed. Thereafter, as shown in FIG. 3C, an ultraviolet ray having a main wavelength of 365 nm is irradiated to polymerize the polymerizable monomer and the oligomer. This allows
As shown in FIG. 3 (d), the polymerizable monomer and the oligomer are polymerized, and a polymer network type liquid crystal element in which spherical liquid crystal droplets 14 as a liquid crystal material are continuously connected and dispersed in a polymer matrix is produced. Is done. It is needless to say that a polymer dispersed liquid crystal element in which liquid crystal droplets are dispersed in a polymer matrix may be structurally used.
Next, as shown in FIG. 3E, the liquid crystal structure is deformed to slightly extrude the liquid crystal inside the liquid crystal panel.

In the step of deforming the liquid crystal structure, a pressing method is used in the present embodiment. Specifically, the panel after the UV polymerization was pressed using a jig (apparatus) as shown in FIG. At this stage of the deformation step, the panel is not yet sealed. Briefly, the procedure of pressing the panel was as follows. A plurality of panels 23 were sandwiched between the platens 21 and 22 of the jig, and a buffer 24 was sandwiched between the panels 23. The platen 21 is configured to move in parallel, and the panel 23 is pressed by tightening a screw attached to the platen 21.

By pressing the panel 23 after the formation of the polymer network structure as described above, the liquid crystal structure was deformed and the liquid crystal inside was slightly extruded as shown in FIG. As a result, as shown in FIG.
4 was able to produce a liquid crystal display device having a flat structure in which the thickness was reduced in the cell thickness direction. According to the experimental results of the present inventor, it was left at room temperature in a pressed state, and 3 hours in the cell thickness direction in 5 hours.
%. At this time, the polymer dispersion type liquid crystal element having a liquid crystal droplet structure can be similarly extruded, so that the polymer material is in a gel state and has a property of allowing the liquid crystal material to pass through for a long time. The degree of deformation can be determined from the change in cell thickness, and the amount of deformation can be changed by changing the standing time and the pressing strength.

In order to deform 3% in the cell thickness direction in 5 hours, a pressing force of 0.8 kg / cm ² or more is required, and in order to shorten the extrusion time, 3 kg / cm ² or more is desirable. 1 to push out within 6 hours
0 kg / cm ² or more is desirable.

When the liquid crystal structure is deformed as described above, various characteristics of the liquid crystal display element are largely changed.
Here, in order to quantify the structural change, the deformation rate P
(%) = (Cell thickness before deformation−cell thickness after deformation) / (cell thickness before deformation) × 100. When applied to the case of FIG. 3, since the cell thickness is reduced from d1 to d2 from the state of FIG. 3D to the state of FIG.
(%) = (D1−d2) / (d1) × 100. This indicates the amount of deformation of the liquid crystal structure. In the case of the liquid crystal droplet structure, it corresponds to the oblateness, and indicates that the thickness of the liquid crystal droplet 14 in the cell thickness direction is reduced by P%. Also in the case of the polymer network structure, the thickness similarly decreases by P%, and the ratio of liquid crystal molecules substantially parallel to the glass substrate at the polymer interface increases. Although the liquid crystal droplet is deformed by this manufacturing process, the length of the liquid crystal droplet in the direction parallel to the substrate hardly changes and the length in the thickness direction changes by P% after the deformation process of P%. This is because the liquid crystal has been extruded by the pressing process, and the volume of the liquid crystal in the liquid crystal droplet has changed. Here, the amount of deformation is defined corresponding to the pressing condition P% in the manufacturing process, and this is defined as “the difference between the length of the liquid crystal droplet in the substrate parallel direction and the length in the thickness direction” of “the difference of the liquid crystal droplet in the substrate parallel direction”. Length ”. In this case, the deformation amount is the same as the pressing condition P%. Therefore, unless otherwise specified as a parameter indicating the degree of deformation of the liquid crystal droplet in the pressing process, in the following description, for convenience, the term “deformation rate” is also used to include the term “deformation amount”. I do.

Next, the characteristics of the liquid crystal display device of the present invention formed as described above will be described with reference to the drawings.
The root of the present invention is that the symmetry of the liquid crystal droplet is broken by deforming the structure of the liquid crystal, and the orientation direction of the liquid crystal is relatively close to the substrate. FIG. 5 illustrates this phenomenon in the case where the liquid crystal droplets are independent of each other and the liquid crystal has a bipolar alignment. When the liquid crystal droplet 14 has a perfect spherical shape as shown in FIG. 5A, the pole (shown by a black circle in the figure) is oriented in an arbitrary direction. This corresponds to a normal polymer dispersion type liquid crystal display element. In this case, the liquid crystal drop 1
Since the shape of No. 4 is symmetric, there is no anisotropy in the shape and no regularity occurs in the direction in which the poles are generated. 0 as in the present invention
FIG.
It has a flat shape as shown in FIG. Thus, the liquid crystal droplet 14
However, when the liquid crystal is deformed into an asymmetric shape, the liquid crystal is aligned according to the asymmetry. In this embodiment, the structure in which the poles of the bipole structure are generated horizontally is stabilized. Although the poles of the bipole are shown as being arranged in one direction on the left and right in the figure, it is intended that the poles are arranged in a horizontal direction. FIG. 5C is a schematic diagram viewed from above. Since the orientation of the liquid crystal is caused by the asymmetry of the structure of the liquid crystal droplet 14, the orientation of the liquid crystal can be made sufficiently close to horizontal even if the amount of deformation is relatively small.

However, we have found that excessive deformation of more than 10% deteriorates the properties. This is because when the deformation of the liquid crystal droplet becomes 10% or more, the shape of the liquid crystal droplet 14 becomes close to a disk shape. At this time, the liquid crystal molecules are deformed,
There is a tendency to line up in the vertical direction in the figure. This is a liquid crystal drop 14
Is close to a disk shape, liquid crystal molecules are aligned in the short axis direction of the liquid crystal droplet 14 due to the effect of the excluded volume of liquid crystal or the effect of packing. The liquid crystal in this example has a tendency to line up parallel to the polymer interface, but when the deformation increases, the liquid crystal tends to line up vertically due to the excluded volume, rather than the liquid crystal tends to line up parallel to the polymer interface. As a result, the phenomenon that the liquid crystal molecules stand vertically as shown in FIG. 5D was confirmed. FIG. 5E is a schematic view of the liquid crystal droplet 14 of FIG. 5D as viewed from above.

It has been found that the phenomenon that the liquid crystal stands vertically due to the excessive deformation also depends on the size of the liquid crystal droplet 14, and it is difficult to stand vertically when the liquid crystal droplet 14 is large. The size of the liquid crystal droplet 14 here is the longer diameter as observed from above. If it is 10 μm or more, the liquid crystal tends to be relatively hard to stand. The smaller the particle size is, the higher the scattering intensity is. Therefore, when used for a scattering type liquid crystal display element, it is preferable that the particle size is 2 μm or less. . Note that all data described below is for the case where the diameter of the liquid crystal droplet 14 is about 1.2 μm.

The interaction between the polymer interface and the liquid crystal and the dependence of the anchoring strength were also found, and it was found that the stronger the anchoring, that is, the more the liquid crystal had a tendency to line up horizontally at the polymer interface, the more difficult it was to stand vertically. Was. If the anchoring strength is high, there is a problem that the driving voltage becomes high,
Although it is difficult to use as a scattering type liquid crystal display device, when a sufficient driving voltage is applied, larger scattering can be obtained. As described above, by slightly deforming the liquid crystal droplet 14 by about 10% or less, the symmetry of the liquid crystal droplet 14 was broken, and as a result, the liquid crystal molecules could be made nearly parallel to the substrate. By arranging the liquid crystal molecules in this manner, the following device characteristics were obtained.

First, FIG. 6 shows a change in transmittance at the time of scattering with a change in the deformation rate P described above. Here, the vertical axis of FIG. 6 indicates the transmittance when no electric field is applied. In FIG. 6, a line M1 shows a change when the anchoring strength is normal,
Line M2 indicates a change when the anchoring strength is high. In FIGS. 7, 8 and 10, which will be described later, the line M1 shows a change when the anchoring strength is normal, and the line M2 shows a change when the anchoring strength is strong. However, methods for evaluating anchoring strength are not standardized at present. Then, the present inventor evaluated the anchoring strength using the following evaluation parameters. (Driving voltage V ₉₀ when not deformed) / (particle size) In this embodiment, the above evaluation parameter when the anchoring strength is normal is about 6.5, and the above evaluation when the anchoring strength is strong. The parameter was about 11.5. As described later in detail, when the evaluation parameter is 10 or more, 20
%, A scattering state is observed, and deformation up to 20% is effective for improving characteristics.

First, the case where the anchoring strength indicated by the line M1 is normal will be described. Line M1 in FIG.
As shown in the above, the transmittance decreases as the deformation rate increases in the range of the deformation rate P of 0 to 10%. Since the transmittance becomes smaller as the scattering becomes stronger, the scattering intensity, which is the reciprocal of the transmittance, increases as the deformation rate P increases in the range of the deformation rate P of 0% to 10%. To obtain high contrast, high scattering intensity and low transmittance are desired. The reason why the scattering intensity is increased as described above is that the liquid crystal molecules are arranged close to the direction parallel to the substrate. The refractive index anisotropy Δn in the direction parallel to the substrate that contributes to the scattering is effectively increased when the liquid crystal molecules are closer to the horizontal direction, so that the scattering is increased. In order to maximize scattering as a device, a deformation rate of 3
-10% is most desirable. Also, when a dichroic dye is contained, the dichroic dye molecules are also aligned nearly horizontally by arranging the liquid crystal molecules nearly horizontally. As a result, the dichroic ratio of the dichroic dye was improved, so that the absorptance was improved and a high contrast was obtained.

However, as shown by the line M1 in FIG. 6, when the deformation ratio is 10% or more, the scattering intensity rapidly deteriorates.
Actually, there is a problem that the scattering intensity is deteriorated rather than performing the deformation. This is because if the liquid crystal droplets have an excessively flat shape, the liquid crystal molecules have a strong tendency to be arranged vertically to the substrate.

The improvement in the scattering intensity depends on the refractive index anisotropy Δn of the liquid crystal material. The effect was observed when Δn was 0.245 or more, and was remarkable when it was 0.26 or more.

Next, FIG. 7 shows a change in the drive voltage V90 at the same cell thickness according to the change in the deformation rate P. here,
V90 means a driving voltage when the transmittance is 90%. As is clear from the results shown in the line M1 in FIG. 7, the V90 decreases as the deformation rate P increases. This is also because the effective orientation anisotropy Δε increases as the orientation direction of the liquid crystal molecules approaches the substrate. Note that this V
90 depends on the dielectric anisotropy Δε of the liquid crystal material.
When ε is 5 or more, a decrease in V90 is observed.
90 was remarkably reduced.

FIG. 8 shows a change in steepness with a change in the deformation ratio P. Here, the index γ indicating the steepness is, as shown in FIG. 9, the driving voltage V90 when the transmittance is 90%.
And the drive voltage V10 when the transmittance is 10%. That is, γ is represented by γ = V90 / V10. As is clear from the result shown in line M1 of FIG. 8, the value of γ decreases as the deformation rate P increases.
That is, the steepness increases as the deformation rate P increases.

FIG. 10 shows the change in the response speed with the change in the deformation rate P. Here, the following values were used to evaluate the response speed. That is, V9 shown in FIG.
Alternating waveforms of 0 and V10 are alternately applied to the liquid crystal panel. Then, as shown in FIG. 11A, the transmitted light amount in this case ranges from 10% (that is, 80% × 10%) to 90% (that is, 80%) within a change amount range between 10% and 90%.
× 90%) rise time T1 required to change to
And 90% (ie, 80% × 90%) to 10% (ie, 8
0% × 10%)
The value obtained by adding 2 was used as an evaluation value of the response speed. As is apparent from the line M1 in FIG. 10, the response speed decreases as the deformation rate P increases.

The reason why the response speed decreases as the deformation rate P increases as described above includes that the applied voltage V90 decreases. However, basically, the orientation of the liquid crystal molecules is relatively small. The reason for this is that the momentum required for the molecules to stand by voltage application increases because they become nearly parallel to the substrate.

As described above, there is an advantage that the scattering intensity is increased by the deformation rate P and the V90 is reduced, but there is a problem that the response speed is reduced. When a TFT substrate is used as in the present embodiment, it is not necessary to sharpen the γ characteristic.
If the γ characteristic is ignored, it is desirable that the deformation ratio P (%) satisfies the relationship of 10% or less. This corresponds to line M in FIG.
According to the result shown in FIG. 1, although the transmittance once decreases as the deformation rate increases, when the deformation rate exceeds 10%, the transmittance becomes higher than when no deformation occurs.

From the viewpoint of desirably placing importance on the response speed, it is desirable that the deformation ratio P (%) satisfies the relationship of 5% or less. This is because the response speed suddenly increases at a deformation rate of 5% from the result shown in the line M1 in FIG.

In the above description, the liquid crystal droplet is deformed, but it is essential that the liquid crystal droplet is deformed so that the orientation direction of the liquid crystal molecule is relatively close to the substrate (in other words, the liquid crystal molecule is deformed). To control the effective tilt angle (θp). Here, the effective tilt angle of the liquid crystal molecule is an index indicating how many times the average azimuth of the liquid crystal molecule is tilted from the direction parallel to the substrate when no electric field is applied. On the other hand, when the liquid crystal molecules are made parallel to the substrate as described above, the dielectric constant changes. Therefore, by defining the dielectric constant of the liquid crystal, it is possible to obtain a liquid crystal display element that improves the scattering characteristics without deteriorating the display characteristics, further increases the steepness of the amount of transmitted light with respect to the voltage, and enables simple matrix driving. Can be.

According to the present inventors, it has become possible to define the dielectric constant experimentally. Specifically, when the dielectric constant is measured by applying a minute voltage of about 0.1 [V], the measured value is the dielectric constant under a minute voltage. It is considered that there is almost no error. Therefore, the experiment was performed by regarding the measured value as the dielectric constant without applying a voltage. More specifically, experiments were performed on liquid crystal droplets having various deformation rates from liquid crystal droplets that were not deformed at all.

As a result, the dielectric ratio E is given by E = (εL−ε⊥)
When defined as / Δε, when E is 0.08 or more and less than 0.345, an improvement in the scattering characteristics and a reduction in voltage can be realized. The above-mentioned εL indicates the permittivity without applying a voltage, ε⊥ indicates the permittivity in the vertical direction of the liquid crystal molecules, and Δε indicates the difference between the permittivity ε‖ in the direction parallel to the liquid crystal molecules and the ε⊥. Further, it is preferable that E is 0.11 or more and less than 0.345. Note that when E is 0.345, the value is a value when the liquid crystal itself is not deformed at all, and when E is 0.08, the deformation ratio P is 10, and when E is 0.11, In some cases, the deformation rate P is 5.

As described above, the desired dielectric constant of the liquid crystal can be specified experimentally. On the other hand, the relationship between the effective tilt angle (θp) of the liquid crystal molecules and the dielectric constant εL of the liquid crystal is as follows. , ΕL = ε⊥ + Δε × sin2θp. Therefore, it is also possible to define the effective tilt angle (θp) of the liquid crystal molecules from the above value of E.

Assuming that the absolute value of the angle at which the rod-like liquid crystal molecules are inclined from the direction parallel to the substrate is θ, and that the average value of all the liquid crystal molecules is θp, the condition of E is that the range of θp is 17 Not less than 35.5, more preferably 20
This is less than 35.5. Note that the above θp is 35.5.
Is a value when the liquid crystal itself is not deformed at all. Table 1 below shows the correspondence between the dielectric ratio E, the average value θp, and the deformation ratio P.

[0050]

[Table 1]

Next, characteristics when the anchoring strength is high will be described with reference to FIGS. 6, 7, 8, and 10. FIG.
The characteristics in the case where the anchoring strength is high are indicated by a line M2 in FIGS. 6, 7, 8, and 10. When the anchoring is strong, the same phenomenon as in the case where the anchoring strength is normal occurs, but the tendency that the liquid crystal starts to stand in the direction perpendicular to the substrate is weakened. This corresponds to line M in FIGS. 6, 7, 8 and 10.
It is clear from FIG. As for the relationship between the transmittance at the time of scattering shown in FIG. 6 and the deformation rate, as shown by the line M2, almost the maximum scattering intensity is obtained at the deformation rate of 10%, that is, the minimum transmittance is obtained. The rate increases, and at 20%, it is almost the same value as the initial state in which no deformation occurs. Therefore, 20
%, The scattering is worse than in the initial state, and the effect of improving the scattering is not seen. In other words, when the anchoring strength is high, the effect of improving the scattering properties is seen at a deformation rate of 20% or less as shown by the line M2. FIG.
As shown in the line M2, the effect that the drive voltage is also reduced by the deformation rate P is that the anchoring strength is the normal line M1.
Is the same as However, if the anchoring strength is high, there is a problem that the drive voltage increases. In the case of this embodiment, almost twice the voltage is required. If the anchoring strength is high, there is a problem that the driving voltage increases. However, if the voltage can be increased by the driving method, this is an effective means. FIG. 8 shows the relationship of steepness, but there is basically no difference from the case where the anchoring strength is normal. FIG. 10 shows the relationship between the response speeds. The higher the anchoring is, the faster the response speed is. This depends on the applied voltage being high.

(Embodiment 2) In this embodiment, heat treatment is performed for extrusion. The polymer dispersion type liquid crystal element or the polymer network type liquid crystal element after the polymerization was kept at 120 ° C. for 50 hours without sealing. This treatment also reduced the cell thickness by 3%, and obtained the same characteristics as described above. This is due to volume expansion due to heat treatment.
That is, the liquid crystal material expands with a volume expansion coefficient of about 0.3 × 10 ⁻³ [K ⁻¹ ]. Therefore, at a high temperature of 120 ° C., the liquid crystal material is in an expanded state, and the internal pressure is increased, so that the liquid crystal material is in the same state as when pressed. For this reason, the liquid crystal flows out from the unsealed injection port, and extrusion is realized. Further, by raising the temperature to an isotropic liquid phase at a temperature higher than that of the nematic phase by heating, the fluidity became extremely high, and extrusion was performed effectively.

(Embodiment 3) In this embodiment, both pressurization and heating are used for extrusion. The liquidity of the liquid crystal is not high only by the pressurization as described in Embodiment 1, so that it takes a relatively long time. Here, it was left at a high temperature (120 ° C.) while applying pressure with the jig of the first embodiment. Leaving at a high temperature increases the fluidity and can reduce the time required for extrusion. In this embodiment, a deformation rate of 3% was achieved in 3 hours.

(Embodiment 4) In this embodiment, FIG.
As shown in FIG. 2, a vacuum pack was used for pressurization. In the first and third embodiments, the pressing jig is used. However, uneven pressing may occur due to dust entering between the panels. In the present embodiment, the liquid crystal panel is housed in the pack 30, and the air in the pack 30 is sucked to be in a vacuum state, so that the liquid crystal panel can be pressed uniformly. However, sufficient time is required because atmospheric pressure is applied. Deformation rate 3
It took 30 hours at 120 ° C. to obtain%.

(Embodiment 5) In the present embodiment, hydrostatic pressure application is used for pressurization. The liquid crystal panel described above was subjected to a vacuum packing process, and was immersed in a pressurized water tank to apply pressure to the panel. At this time, the water pressure was 1 kbar. As a result, a deformation rate of 3% was obtained in 8 hours at room temperature.

(Embodiment 6) In this embodiment, a roller press is used for extrusion. Specifically, as shown in FIG. 13, the liquid crystal was extruded by passing the panel 23 between the roller 71A and the roller 71B having the heating means 73 therein. It was realized in 30 minutes to obtain a deformation rate of 1%.

(Embodiment 7) In the present embodiment, the extrusion is performed by using the volume expansion of chalcogenide glass. The present embodiment is substantially the same as the first embodiment, except that a chalcogenide glass layer is formed on the inner side of the electrode 12 of the substrate 11. It is a feature of the process to have a step of irradiating light. It is generally known that a chalcogenide glass (for example, As2S3) expands in volume when irradiated with a laser beam (for example, see JP-A-8-86903). This chalcogenide glass layer is formed in the liquid crystal panel in advance. After a liquid crystal is separated and separated by ultraviolet irradiation to obtain a polymer network structure, the chalcogenide glass layer is irradiated with a laser beam. At this time, the chalcogenide glass was expanded, the internal pressure in the liquid crystal panel was increased, and the liquid crystal was extruded.

(Embodiment 8) Embodiments 1 to 6 above
In this method, the liquid crystal was extruded by pressing or the like after the polymerization, and the liquid crystal was deformed in the cell thickness direction to make the orientation direction of the liquid crystal molecules relatively parallel to the substrate. In contrast, in the present embodiment,
The feature is that the orientation direction of the liquid crystal molecules is close to the substrate parallel without deformation of the liquid crystal. Since liquid crystal molecules have the property of being arranged along a magnetic field, they have succeeded in relatively aligning the liquid crystal molecules in the direction parallel to the substrate by rotating them in a magnetic field.

More specifically, as shown in FIG. 14, a turntable 85 was set in a magnetic field generated by a magnetic field applying means 84, and the polymerization process described in the first embodiment was performed on the turntable 85. The ultraviolet light from the ultraviolet lamp 81 is
The light is applied to the liquid crystal panel 23 mounted on the turntable 85 via the filter 82. Thereby, the polymerization of the monomer proceeds, and the liquid crystal is deposited. At this time, if a magnetic field is applied, the liquid crystal molecules tend to line up in the direction of the magnetic field. Here, since the turntable 85 is rotating, there is a high probability that the liquid crystal molecules are oriented in the direction parallel to the substrate, and the orientation direction in the direction parallel to the substrate is uniform as shown in FIG. Further, by the rotation of the turntable 85, as shown in FIG. 16, the orientation in the in-plane direction becomes random. Here, FIG. 16 is a conceptual diagram when the element is viewed from above.
In FIGS. 15 and 16, the orientation of the liquid crystal molecules is indicated by arrows.

When the effective tilt angle is reduced by pressing deformation, it is difficult to press uniformly in the cell thickness direction, and shear stress occurs in the direction parallel to the substrate, and the long axes of the liquid crystal droplets are aligned in the shear direction. There was a tendency. In this regard, by rotating the turntable 85 in a magnetic field as in the present embodiment, the orientation of the liquid crystal molecules is relatively close to the substrate interface and random in the in-plane direction of the substrate. And the scattering intensity could be further improved.

When the effective tilt angle of the liquid crystal is controlled by a magnetic field as in this embodiment, the shape of the liquid crystal droplet is close to a sphere,
It is not particularly deformed. However, the effective tilt angle (θp) of the liquid crystal molecules was 30 ° when the magnetic field strength was 0.3 Tesla, and the ratio in the direction parallel to the substrate was relatively increased. The degree of molecular orientation depends on the magnetic field strength, and an effect was observed at 0.1 Tesla or more. When the magnetic field strength was 3 Tesla or more, the effective tilt angle (θp) of the liquid crystal molecules was almost 0 °.

When the polymer-dispersed liquid crystal element is deformed by pressing, scattering starts to deteriorate at a deformation ratio of 10% or more, and rapidly deteriorates. This is because the larger the deformation, the more the liquid crystal molecules are packed, and the molecules start to stand perpendicular to the substrate, increasing the effective tilt angle. Therefore, there is a limit in reducing the effective tilt angle in the deformation. However, the effective tilt angle could be reduced to 0 degrees by reducing the tilt angle of the molecule without depending on the deformation as in the present embodiment. Thereby, the scattering intensity could be increased without deterioration of the scattering intensity as shown in FIG. That is, according to the present embodiment, θp is 0 or more and 35.5.
Good characteristics can be obtained within the range of less than. In addition,
The conditions are as follows: the dielectric constant of the liquid crystal in the composite is εL, the dielectric constant of the liquid crystal alone in the direction perpendicular to the liquid crystal molecules is ε⊥, the dielectric anisotropy of the liquid crystal alone is Δε, and the dielectric ratio is E = (ΕL −ε
⊥) / Δε, E is 0 or more and 0.
In the present embodiment, if the azimuthal angle of the liquid crystal molecules in the direction parallel to the substrate has no anisotropy, scattering is likely to occur, which is convenient.

(Embodiment 9) As shown in FIG. 17, even when polymerization is performed by polarized ultraviolet light during polymerization, the orientation of liquid crystal molecules is made close to the substrate parallel without pressing similarly to the embodiment 7. Was completed.

Specifically, when ultraviolet rays were irradiated to polymerize the monomer and precipitate the liquid crystal, polarized ultraviolet rays were irradiated. Here, the ultraviolet polarizer 90 was installed between the liquid crystal panel 23 and the ultraviolet lamp 81 and was rotated. Polarized ultraviolet rays hit the panel, and polymerization of the monomer proceeds with anisotropy in the polarization direction. Due to the change of the polarization direction, the direction in the substrate plane is not uniform, but the direction in the direction parallel to the substrate is more likely to be close to parallel.

(Embodiment 10) In this embodiment, a polymer-dispersed liquid crystal element which is flattened by being polymerized at a high temperature,
Alternatively, a polymer network type liquid crystal display device was realized. As described in Embodiment Mode 1, the liquid crystal panel into which the mixture of the liquid crystal and the monomer is injected is heated to a high temperature, and is irradiated with ultraviolet light at this temperature to separate and separate the liquid crystal. A liquid crystal formed at a high temperature has an isotropic shape at a high temperature, and a spherical shape in a polymer dispersed liquid crystal element. When this is cooled to room temperature, the volume of the liquid crystal shrinks. Here, since the shrinkage ratio of the glass is small, the shrinkage in the substrate surface is small. Therefore, volume shrinkage occurs in the cell thickness direction. When polymerized at 60 ° C. and cooled to 30 ° C., volume shrinkage of as much as 3% occurred in the cell thickness direction. This is equivalent to the case where the deformation ratio P (%) is 3%, and similar characteristics were obtained.

In order to obtain a deformation rate P of 0.5%, 35 ° C.
It is preferable that the polymerization be carried out at 40 ° C. or higher to obtain a sufficient effect. In addition, a problem that the size of the polymer matrix becomes large from around 70 ° C.
Above ℃, the problem of volatilization of the monomer material was observed. The polymerization temperature may be 35 ° C or more and 80 ° C or less, and preferably 40 ° C or more and 70 ° C or less.

(Embodiment 11) In this embodiment, TF
It was used for simple matrix driving without using a T substrate. The panel configuration is almost the same as that of the first embodiment, but the substrate used is a substrate that does not use a TFT. Therefore, a selection signal is scanned on one substrate, and a signal corresponding to the presence or absence of display is applied to the other substrate. A simple matrix is not required as much as a TFT panel even if the response time is relatively slow or the scattering is slightly worse. Rather, there is a merit that the cost is extremely reduced.

As described in the first embodiment, the steepness is increased by increasing the deformation rate. As shown in FIG. 8, when the deformation ratio is 8% or more, γ is 1.3 or less, and simple matrix driving of 10 lines or more is possible. However, the deformation rate is 20
%, There is a problem that the scattering intensity at low temperatures is extremely deteriorated, and it is difficult to use. At 20% or more, since the pressure is considerably reduced, there is a problem that air bubbles are easily generated at a low temperature. In addition, from the viewpoint of relatively emphasizing the response speed, it is desirable to suppress the deformation rate to 15% or less.

At this time, the effective tilt angle (θp) of the liquid crystal molecules is 10 or more and 18 or less, preferably 13 or more and 18 or less.
And the dielectric ratio (E) is 0.03 or more and 0.10 or less, preferably 0.05 or more and 0.10 or less.

(Embodiment 12) FIG. 18 is a sectional view of a liquid crystal display device according to Embodiment 11 of the present invention, and FIG. 19 is a plan view thereof. FIG.
In FIG. 19 and FIG. 19, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The difference from the first embodiment is that the liquid crystal droplet 14A has a spherical shape instead of a flat structure, and that the orientation of the liquid crystal molecules of the liquid crystal droplet 14A in the substrate plane is made more random.

In FIG. 18, the arrangement of the liquid crystal molecules is illustrated as a bipole structure having two poles in the horizontal direction of the drawing, but this is intended that the bipole axis exists substantially parallel to the substrate. It is not intended that the bipole axes be aligned in one axial direction. As shown in FIG. 19, the bipole axis exists more randomly in the substrate surface than in the first embodiment.

As described above, by making the alignment direction of the liquid crystal molecules nearly horizontal, the refractive index anisotropy Δn in the direction parallel to the substrate which contributes to the scattering is effectively increased, as in the above embodiment. The scattering intensity can be increased. Further, since the effective dielectric anisotropy Δε also increases, the driving voltage also decreases. Further, since the arrangement inside the liquid crystal droplets is uniform in most of the liquid crystal droplets 14A, there is an advantage that the γ characteristic of the drive voltage is also sharpened.

Next, a method of manufacturing the liquid crystal display device having the above-described configuration will be described. First, two substrates 11 are attached to each other so as to face each other. A transparent electrode 12 is formed inside each substrate, and a TFT is provided on one substrate.
An active matrix substrate on which a transistor is formed is used. The distance (cell thickness) between the substrates 11 can be kept constant by, for example, spraying resin beads having a particle diameter of 12 μm in advance.

Next, a mixture of a liquid crystal, a polymerizable monomer, an oligomer and a polymerization initiator is introduced between the substrates 11 by vacuum injection. Thereafter, ultraviolet rays having a main wavelength of 365 nm are irradiated to polymerize the polymerizable monomer and oligomer, and a spherical liquid crystal droplet 14 as a liquid crystal material is placed in a polymer matrix.
A polymer network type liquid crystal element in which A is continuously connected and dispersed is prepared. It is needless to say that a polymer dispersed liquid crystal element in which liquid crystal droplets are dispersed in a polymer matrix may be structurally used.

The feature of the present invention is to use a liquid crystal monomer as the polymerizable monomer at this time. Here, the liquid crystal monomer is also called a UV-curable liquid crystal, and is a compound showing a liquid crystal state in a monomer state (for example, Proceedings of the 22nd Liquid Crystal Symposium by Hasebe et al., 39)
See page 1).

When this liquid crystal monomer is used as a polymerizable monomer, the mixture of the liquid crystal, the polymerizable monomer, the oligomer and the polymerization initiator exhibits a uniform liquid crystal phase at room temperature. When this mixture is injected between the above-mentioned substrates, in this embodiment, the mixture of the liquid crystal and the liquid crystal monomer is arranged in parallel to the substrate. In the case of the present invention, it is not necessary to particularly coat the substrate surface.
A horizontal alignment film used in devices and the like may be applied. However, a rubbing process for arranging in one direction unlike the TN element is not performed.

From the state before the polymerization, the mixture shows a liquid crystal state, and its molecules are arranged in parallel to the substrate. However, since the rubbing process is not performed, they are arranged in a random orientation on the substrate surface. FIG. 20 shows this state. That is, FIG. 20 shows a state before polymerization, and FIG. 20 (a) is an overall view.
0 (b) is a partially enlarged view of FIG. 20 (a). In the figure, the liquid crystal molecules are depicted as being arranged side by side for simplicity, but this is conscious of being arranged horizontally, and is not necessarily arranged in one direction. When viewed from above, the orientation is random. When the mixture in this state is irradiated with ultraviolet light, the liquid crystal monomer 100 is polymerized and the liquid crystal monomers 100 are bonded to each other. Therefore, the molecules of the liquid crystal monomer 100 become larger, and the liquid crystal molecules 101 are eliminated. Therefore, as the polymerization proceeds, the liquid crystal and the polymerized liquid crystal monomer 100 are separated. In this embodiment, the liquid crystal was in the form of drops or a network. FIG. 21 shows this state. FIG. 21A is an overall view, and FIG. 21B is a partially enlarged view of FIG. However, since the liquid crystal was arranged in parallel with the substrate from the initial state, the liquid crystal is affected even after polymerization, and tends to be arranged in parallel with the substrate. According to the invention, after polymerization, the liquid crystal molecules 10
The state in which 1 is arranged almost parallel to the substrate is a liquid crystal monomer 10
0 could be achieved.

It can be said that the present invention is characterized in that the mixture is in a liquid crystal state, and this state is irradiated with ultraviolet rays to be separated. In the conventional example using a polymerizable monomer other than the conventional liquid crystal monomer, the mixture of the liquid crystal, the polymerizable monomer, the oligomer, and the polymerization initiator is a uniform isotropic liquid phase as shown in FIG. When the mixture of the isotropic liquid phases is irradiated with ultraviolet rays, the monomer is polymerized and the liquid crystal precipitates and separates. At this time, the liquid crystal molecules have an orientation orientation that is not as shown in FIG. It will be in a state of being uniformly distributed. In FIG. 22, the alignment direction of the liquid crystal molecules is indicated by arrows.

On the other hand, the mixture in the case where the liquid crystal monomer is used as the polymerizable monomer in the present invention shows a uniform liquid crystal phase from the state before the polymerization, as shown in FIG. Then, a polymerization process in which liquid crystal is precipitated from the liquid crystal. Because of this, because of the influence of the initial orientation,
If the initial stage is arranged horizontally on the substrate, the tendency of the liquid crystal molecules to be nearly horizontal even after polymerization becomes stronger.

When a mixture using such a liquid crystal monomer as a polymerizable monomer is injected between a pair of substrates 11 and then irradiated with ultraviolet rays, the liquid crystal monomer and the oligomer are polymerized with a polymerization initiator as a nucleus. As a result, a liquid crystal droplet 14A (or a polymer network) is formed. Here, if the conditions are set so that the molecules are arranged in parallel to the substrate interface in the liquid crystal phase before polymerization, the orientation of the liquid crystal molecules after polymerization is affected by the parallel state before polymerization, as shown in FIG. As shown in b), the tendency to be parallel to the substrate interface becomes closer, and ideally, a structure in which the bipole axes are arranged parallel to the substrate interface is obtained.
Note that the liquid crystal monomer may contain chiral carbon. With this configuration, the liquid crystal molecules have a structure of spiraling in the cell thickness direction, so that the scattering effect can be further improved.

In this embodiment, as an example, a polyimide film (trade name: RN740, manufactured by Nissan Chemical Industries, Ltd.) is applied and baked on the glass substrate 11 so that the alignment of the liquid crystal molecules before polymerization is applied to the substrate interface. It was almost parallel. Here, it is not necessary to perform a rubbing treatment on the polyimide film, and there is also an advantage of simplifying the process. If the rubbing treatment is performed, the orientation directions of the liquid crystal are arranged in a uniaxial direction, which is not suitable for the present invention. Rather, it is desirable that the initial orientation direction is random without performing the orientation process. In this example, the molecules were parallel to the glass interface in the pre-polymerization state without any particular orientation treatment, but were oriented in a random orientation within the substrate plane. Therefore, the orientation of the liquid crystal molecules after the formation of the liquid crystal droplets was also random in the in-plane direction of the substrate, but tended to be aligned parallel to the substrate interface. At this time, the effective tilt angle (θp) of the liquid crystal molecules was small, that is, 20 °.

As described above, in the liquid crystal display device according to the present embodiment, by making the orientation of the liquid crystal molecules parallel to the glass interface, the same effect as in the above embodiment can be obtained, and the liquid crystal molecule substrate can be obtained. Since the orientation in the in-plane direction was made more random than in the above-described embodiment, the scattering characteristics could be further improved.

In this regard, for reference, in the method of performing polymerization in a magnetic field or in the method of performing polymerization with polarized ultraviolet light as in the above-described Embodiments 8 and 9, the turntable rotation speed or Since it is necessary to control the rotation speed of the polarizing plate, it is difficult to completely randomize the orientation in the in-plane direction of the substrate. In the case of this embodiment, there is an advantage that the orientation in the in-plane direction of the substrate can be completely randomized by the simple technique as described above, and the manufacturing is easy.

Next, the characteristics of the liquid crystal display element according to the present embodiment manufactured by the above method and the liquid crystal display element manufactured by the conventional manufacturing method using no liquid crystal monomer as a polymerizable monomer were compared. did. The characteristics of the liquid crystal display element include a scattering gain, a driving voltage, and a γ characteristic. Here, the scattering gain is an index indicating the degree of scattering. When the scattering gain is G, it is represented by G = (panel luminance / panel illuminance) × π. Note that the liquid crystal display device according to the present embodiment was compared for a case where the effective tilt angle (θp) of liquid crystal molecules was 20 °.

As in the present embodiment, by making the arrangement direction of the liquid crystal molecules close to horizontal, in other words, by reducing the effective tilt angle (θp) of the liquid crystal molecules, or by reducing the dielectric ratio E. As shown in Table 2, the scattering characteristics were improved, the driving voltage was reduced, and the γ characteristics were sharpened.

[0086]

[Table 2]

According to the experimental results of the present inventor, in order to improve the scattering intensity, when θp is less than 35.5, the characteristics are improved, and when θp is 20 or less, the contrast is remarkably improved. . When expressed by the dielectric ratio E instead of the effective tilt angle θp, the dielectric ratio E is 0 to 0.345.
If it is less than 0.1, the characteristics are improved, and if it is 0.11 or less, the contrast is significantly improved.

Further, with respect to the refractive index anisotropy Δn of the liquid crystal monomer, when Δn is large, there is a problem that the transparency when a voltage is applied is deteriorated. Regarding this point, according to the experiment of the inventor, if Δn is 0.20 or less, there is no practical problem,
If it is 0.15 or less, a transmittance comparable to that of a normal acrylic monomer was obtained.

(Embodiment 13) In this embodiment, as shown in FIG. 23, one of the pair of substrates 11 is subjected to fine rubbing in a plurality of directions, and the other is 24, fine irregularities were formed.
The other points are the same as in the twelfth embodiment.

The fine rubbing has an uneven pitch of 20 μm.
Was pressed against the surface of the substrate 11 and rubbed a plurality of times in a plurality of directions. At this time, a polyimide film (trade name R manufactured by Nissan Chemical Industries, Ltd.) was used as the alignment film.
N740) was used. On the other substrate 11, irregularities were formed with an acrylic resin, and random irregularities having a pitch of 1 μm and a height of 0.1 μm were formed.

As described above, by the fine rubbing and the formation of the surface irregularities, the direction in which the molecules of the mixture before polymerization are arranged can be made more randomly and finely, and the scattering intensity can be further increased.

In the present embodiment, fine rubbing is performed on one substrate and fine irregularities are formed on the other substrate, but fine rubbing is performed only on one substrate, As the substrate, an ordinary substrate may be used without forming fine irregularities. Similarly, fine irregularities may be formed only on one substrate, and the other substrate may be a normal substrate that is not subjected to a rubbing process.

In the twelfth and thirteenth embodiments, the liquid crystal display device driven by the active matrix is described. However, the present invention using the liquid crystal monomer as the polymerizable monomer is applied to the liquid crystal display device driven by the simple matrix. Can also be suitably implemented. When the present invention is applied to a liquid crystal display element driven by a simple matrix, the effective tilt angle (θp) of the liquid crystal molecules is set to 10 or more and 18 or less, desirably 13 or more and 18 or less as in the eleventh embodiment. Expressed as (E), the dielectric ratio (E) may be set to be 0.03 or more and 0.10 or less, preferably 0.05 or more and 0.10 or less.

[0094]

As described above, according to the present invention, in a liquid crystal display device in which a liquid crystal is dispersed in a polymer, the liquid crystal molecules are tilted in an optimum range in a direction parallel to the substrate to obtain a scattering characteristic. And the drive voltage can be reduced. In particular, when a liquid crystal monomer is used as the polymerizable monomer, in addition to the above-described effects, the azimuthal angle of the liquid crystal molecules in the substrate surface can be made more nonuniform, and the scattering intensity can be further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 2 is a partial plan view of the liquid crystal display element according to the first embodiment of the present invention.

FIG. 3 is a manufacturing process diagram of the liquid crystal display element according to the first embodiment of the present invention.

FIG. 4 is a front view of an apparatus for manufacturing a liquid crystal display element according to Embodiment 1 of the present invention.

FIG. 5 is a diagram for explaining the relationship between the deformation of the liquid crystal and the orientation of the liquid crystal in the liquid crystal display element according to the first embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the transmittance and the deformation ratio of the liquid crystal display device at the time of scattering in the first embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a driving voltage V90 and a deformation ratio of the liquid crystal display element in Embodiment 1 of the present invention.

FIG. 8 is a diagram showing the relationship between the steepness γ and the deformation ratio of the liquid crystal display element according to the first embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between drive voltages V10 and V90 and transmittance.

FIG. 10 is a diagram illustrating a relationship between a response speed and a deformation ratio of the liquid crystal display element according to Embodiment 1 of the present invention.

FIG. 11 is a diagram showing a change in transmittance with respect to drive voltages V10 and V90.

FIG. 12 is a sectional view of an apparatus for manufacturing a liquid crystal display element according to Embodiment 4 of the present invention.

FIG. 13 is a sectional view of an apparatus for manufacturing a liquid crystal display element according to Embodiment 6 of the present invention.

FIG. 14 is a simplified front view of an apparatus for manufacturing a liquid crystal display element according to Embodiment 8 of the present invention.

FIG. 15 is a sectional view of a liquid crystal display element according to Embodiment 8 of the present invention.

FIG. 16 is a partial plan view of a liquid crystal display element according to Embodiment 8 of the present invention.

FIG. 17 is a perspective view of an apparatus for manufacturing a liquid crystal display element in Embodiment 9 of the present invention.

FIG. 18 is a sectional view of a liquid crystal display device according to a twelfth embodiment of the present invention.

FIG. 19 is a partial plan view of a liquid crystal display element according to Embodiment 12 of the present invention.

FIG. 20 is a diagram showing a polymerization process when a liquid crystal monomer is used.

FIG. 21 is a diagram showing a polymerization process when a liquid crystal monomer is used.

FIG. 22 is a state diagram before and after polymerization of a conventional example and a twelfth embodiment of the present invention, respectively.

FIG. 23 is a perspective view of one substrate used in Embodiment 13 of the present invention.

FIG. 24 is a perspective view of the other substrate used in Embodiment 13 of the present invention.

[Explanation of symbols]

 11: Substrate 12: Transparent electrode 13: Polymer 14, 14A: Liquid crystal droplet 21, 22: Surface plate 23: Liquid crystal panel 24: Buffer 30: Pack 71A, 71B: Roller 73: Heating means 81: Ultraviolet lamp 82: Filter 84: magnetic field applying means 90: polarizer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinya Kosako 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. F term (reference) 2H089 HA04 HA06 KA06 KA09 NA22 NA32 NA48 QA12 RA03 RA06 SA16 SA17 TA04 2H090 KA06 KA11 LA03 MA09 MA11

Claims (53)

[Claims] 1. A polymer-dispersed liquid crystal display device in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, wherein the liquid crystal molecules in the liquid crystal droplets are A polymer-dispersed liquid crystal display element characterized by being oriented substantially parallel to the substrate and randomly oriented in a plane parallel to the substrate. 2. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates.
A polymer-dispersed liquid crystal display device in which the liquid crystal droplets are deformed into a flat structure in which the liquid crystal droplets are shrunk in a cell thickness direction, wherein the amount of deformation of the liquid crystal droplets is reduced due to an excluded volume effect of liquid crystal. A polymer-dispersed liquid crystal display device characterized in that the range is such that a phenomenon of rising in the cell thickness direction does not occur. 3. The polymer-dispersed liquid crystal display device according to claim 2, wherein the amount of deformation of the liquid crystal droplet is 20% or less. 4. The polymer dispersed liquid crystal display device according to claim 2, wherein the deformation amount of the liquid crystal droplet is 10% or less. 5. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates.
A polymer-dispersed liquid crystal display device in which the liquid crystal droplets are deformed into a flat structure in which the liquid crystal droplets are shrunk in a cell thickness direction, wherein an average value θp of angles between liquid crystal molecules in the liquid crystal droplets and the substrate is 17 or more. A polymer-dispersed liquid crystal display device having a molecular weight of less than 35.5. 6. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates.
A polymer-dispersed liquid crystal display device in which the liquid crystal droplet is deformed into a flat structure in which the liquid crystal droplet is shrunk in a cell thickness direction, wherein an average value θp of angles formed between liquid crystal molecules in the liquid crystal droplet and the substrate is 20 or more. A polymer-dispersed liquid crystal display device having a molecular weight of less than 35.5. 7. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates.
A polymer-dispersed liquid crystal display device in which the liquid crystal droplet is deformed into a flat structure in which the liquid crystal droplet is shrunk in a cell thickness direction, wherein a dielectric constant of liquid crystal in the liquid crystal droplet in the composite is εL, The dielectric constant in the vertical direction of the molecule is ε⊥, the dielectric anisotropy of the liquid crystal alone is Δε, and the dielectric ratio is E = (εL−ε
Ｅ) / Δε, wherein E is 0.08 or more and less than 0.345. 8. A polymer liquid crystal composite comprising liquid crystal droplets dispersed in a polymer is disposed between a pair of substrates.
A polymer-dispersed liquid crystal display device in which the liquid crystal droplet is deformed into a flat structure in which the liquid crystal droplet is shrunk in a cell thickness direction, wherein a dielectric constant of liquid crystal in the liquid crystal droplet in the composite is εL, The dielectric constant in the vertical direction of the molecule is ε⊥, the dielectric anisotropy of the liquid crystal alone is Δε, and the dielectric ratio is E = (εL−ε
Ｅ) / Δε, wherein E is 0.11 or more and less than 0.345. 9. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates.
A method of manufacturing a polymer-dispersed liquid crystal display device in which the liquid crystal droplets are deformed into a flat structure in which the liquid crystal droplets are shrunk in a cell thickness direction, the method comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between the substrates; And, after separating the liquid crystal, extruding a part of the liquid crystal in the liquid crystal droplet from the space between the substrates to the outside. The deformation ratio P (%) before and after the extruding step is defined as (deformation). Previous cell thickness−cell thickness after deformation) / (cell thickness before deformation) × 1
A method for producing a polymer-dispersed liquid crystal display device, wherein P is 10 or less when 00 is set. 10. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure shrunk in a cell thickness direction. A method of manufacturing a polymer-dispersed liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between the substrates, and separating the liquid crystal; And a step of extruding a part of the cell from the space between the substrates to the outside. The deformation ratio P (%) before and after the extrusion step is calculated by (cell thickness before deformation−cell thickness after deformation) / (cell before deformation). Thickness) x 1
A method for producing a polymer-dispersed liquid crystal display device, wherein P is 5 or less when 00 is set. 11. The method for producing a polymer-dispersed liquid crystal display device according to claim 9, wherein the step of extruding the liquid crystal is a vacuum packing. 12. The method according to claim 9, wherein the step of extruding the liquid crystal is hydrostatic pressure application. 13. The method according to claim 9, wherein the step of extruding the liquid crystal is performed by a pressing force of a roller. 14. The method for producing a polymer-dispersed liquid crystal display device according to claim 9, wherein the step of extruding the liquid crystal is a heating step. 15. The polymer-dispersed liquid crystal display device according to claim 9, wherein the step of extruding the liquid crystal is performed at a temperature higher than a temperature at which the liquid crystal transitions to an isotropic liquid phase. Manufacturing method. 16. The method according to claim 9, wherein the step of extruding the liquid crystal is performed by a volume expansion mechanism inside the liquid crystal panel. 17. An electrode and a chalcogenide glass layer are formed in this order in advance on each of opposing surfaces of the pair of substrates inward, and the liquid crystal is extruded so that the laser light is applied to the chalcogenide glass layer. 17. The method according to claim 16, wherein the step is performed by irradiating the chalcogenide glass layer with volume expansion. 18. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. Liquid crystal display element, wherein liquid crystal molecules in the liquid crystal droplet are oriented substantially parallel to a substrate. 19. The polymer-dispersed liquid crystal display device according to claim 18, wherein liquid crystal molecules in the liquid crystal droplets are randomly oriented in a plane parallel to the substrate. 20. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are not deformed in the cell thickness direction. A liquid crystal display element, wherein an average value θp of an angle between liquid crystal molecules in the liquid crystal droplet and the substrate is 0 or more and less than 35.5. 21. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. Liquid crystal display element, wherein the dielectric constant of the liquid crystal in the liquid crystal droplets in the composite is εL, the dielectric constant of the liquid crystal alone in the direction perpendicular to the liquid crystal molecules is ε⊥, and the dielectric anisotropy of the liquid crystal alone Property is Δε, and the dielectric ratio is E = (εL
−E⊥) / Δε, wherein E is 0 or more and less than 0.345. 22. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. A method of manufacturing a liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between a pair of substrates; and irradiating the mixture with ultraviolet rays to precipitate and separate liquid crystals. A method for producing a polymer-dispersed liquid crystal display device, comprising a step of arranging liquid crystal molecules substantially horizontally on the substrate in the step of separating and separating liquid crystal. 23. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. A method of manufacturing a liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between a pair of substrates; and irradiating the mixture with ultraviolet rays to precipitate and separate liquid crystals. A method for producing a polymer-dispersed liquid crystal display element, wherein a magnetic field is applied between substrates in a step of separating and separating liquid crystal. 24. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. A method of manufacturing a liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between a pair of substrates; and irradiating the mixture with ultraviolet rays to precipitate and separate liquid crystals. The method for producing a polymer-dispersed liquid crystal display device, wherein the ultraviolet light has a polarizing property in the step of separating and separating the liquid crystal. 25. The method according to claim 23, wherein, in the step of separating and separating the liquid crystal, the substrate is rotated around an axis in a vertical direction of the substrate. . 26. The method according to claim 24, wherein in the step of separating and separating the liquid crystal, the polarization direction of the ultraviolet light is rotated in a plane parallel to the substrate. 27. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure contracted in the cell thickness direction. A method of manufacturing a polymer-dispersed liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between a pair of substrates; and irradiating the mixture with ultraviolet rays to precipitate and separate the liquid crystal. A method for producing a polymer-dispersed liquid crystal display device, comprising: heating the mixture to a temperature higher than room temperature in the step of separating and separating the liquid crystal; 28. The method according to claim 27, wherein the mixture is heated to a temperature of 35 ° C. or more and 80 ° C. or less. 29. The method according to claim 27, wherein the mixture is heated to a temperature of 40 ° C. or more and 70 ° C. or less. 30. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure shrunk in the cell thickness direction. A method of manufacturing a polymer-dispersed liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between the substrates, and separating the liquid crystal; And a step of extruding a part of the cell from the space between the substrates to the outside. The deformation ratio P (%) before and after the extrusion step is calculated by (cell thickness before deformation−cell thickness after deformation) / (cell before deformation). Thickness) x 1
A method for producing a polymer-dispersed liquid crystal display device, wherein P is 8 or more and 20 or less when 00 is set. 31. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure shrunk in the cell thickness direction. A method of manufacturing a polymer-dispersed liquid crystal display device, comprising: injecting a mixture containing a liquid crystal material and a polymerizable monomer between the substrates, and separating the liquid crystal; And a step of extruding a part of the cell from the space between the substrates to the outside. The deformation ratio P (%) before and after the extrusion step is calculated by (cell thickness before deformation−cell thickness after deformation) / (cell before deformation). Thickness) x 1
A method for producing a polymer-dispersed liquid crystal display device, wherein P is 8 or more and 15 or less when 00 is set. 32. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure shrunk in a cell thickness direction. A polymer dispersed liquid crystal display device, wherein the average value θp of the angle between the liquid crystal molecules of the liquid crystal and the direction parallel to the substrate is 10 or more and 18 or less. 33. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure shrunk in a cell thickness direction. The liquid crystal molecules of the liquid crystal, the average value θ of the angle between the liquid crystal molecules of the liquid crystal and the substrate.
A polymer-dispersed liquid crystal display device, wherein p is 13 or more and 18 or less. 34. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure contracted in the cell thickness direction. Wherein the dielectric constant of the liquid crystal in the liquid crystal droplets in the composite is εL, the dielectric constant of the liquid crystal molecule in the vertical direction is ε⊥, and the dielectric constant of the liquid crystal alone is The anisotropy is Δε, and the dielectric ratio is E = (εL−ε
Ｅ) / Δε, wherein E is 0.03 or more and 0.10 or less. 35. A polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and the liquid crystal droplets are deformed into a flat structure contracted in a cell thickness direction. Wherein the dielectric constant of the liquid crystal in the liquid crystal droplets in the composite is εL, the dielectric constant of the liquid crystal molecule in the vertical direction is ε⊥, and the dielectric constant of the liquid crystal alone is The anisotropy is Δε, and the dielectric ratio is E = (εL−ε
Ｅ) / Δε, wherein E is 0.05 or more and 0.10 or less. 36. The polymer dispersed liquid crystal display device according to claim 30, which is used in a simple matrix drive display. 37. A polymer dispersion having a structure in which a polymer liquid crystal composite in which liquid crystal droplets are dispersed in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. Liquid crystal display element, wherein the polymer is obtained by a photopolymerization method using a liquid crystal monomer as a polymerizable monomer, and the azimuth of the liquid crystal molecules in the liquid crystal droplets in the in-plane direction of the substrate is random. A polymer dispersed liquid crystal display device, comprising: 38. The refractive index anisotropy Δn of the liquid crystal monomer
Is smaller than 0.20, the polymer dispersed liquid crystal display device according to claim 37. 39. The refractive index anisotropy Δn of the liquid crystal monomer
The polymer dispersed liquid crystal display element according to claim 37, wherein is smaller than 0.15. 40. The polymer dispersed liquid crystal display device according to claim 37, wherein the liquid crystal monomer contains chiral carbon. 41. The polymer according to claim 37, wherein the average value θp of the angle between the liquid crystal molecules in the liquid crystal droplet and the substrate is less than 35.5. Dispersion type liquid crystal display element. 42. The polymer dispersion type according to claim 37, wherein the average value θp of the angle between the liquid crystal molecules in the liquid crystal droplet and the substrate is 20 or less. Liquid crystal display element. 43. The dielectric constant of the liquid crystal in the liquid crystal droplets in the composite is εL, the dielectric constant of the liquid crystal alone in the direction perpendicular to the liquid crystal molecules is ε⊥, and the dielectric anisotropy of the liquid crystal alone is Δε. 41. The polymer dispersion according to claim 37, wherein E is 0 or more and less than 0.345 when the dielectric ratio is E = (εL−ε⊥) / Δε. Liquid crystal display device. 44. The dielectric constant of the liquid crystal in the liquid crystal droplet in the composite is εL, the dielectric constant of the liquid crystal alone in the direction perpendicular to the liquid crystal molecules is ε⊥, and the dielectric anisotropy of the liquid crystal alone is Δε. 41. The liquid crystal display device according to claim 37, wherein, when the dielectric ratio is E = (εL−ε⊥) / Δε, E is 0 or more and 0.11 or less. . 45. The polymer dispersion type according to claim 37, wherein at least one of the pair of substrates is subjected to rubbing treatment in a plurality of directions. Liquid crystal display element. 46. The polymer-dispersed liquid crystal according to claim 37, wherein fine irregularities are formed on at least one of the pair of substrates. Display element. 47. A polymer dispersion in which a polymer liquid crystal composite formed by dispersing liquid crystal droplets in a polymer is disposed between a pair of substrates, and wherein the liquid crystal droplets are not deformed in the cell thickness direction. A method of manufacturing a liquid crystal display device, comprising a step of injecting a mixture containing a liquid crystal material and a polymerizable monomer between a pair of substrates, and a step of irradiating the mixture with ultraviolet rays to polymerize the monomer to separate liquid crystals. A method for producing a polymer-dispersed liquid crystal display device, wherein the mixture before polymerization shows a liquid crystal phase. 48. The molecular alignment state of the mixture exhibiting the liquid crystal phase is parallel to a substrate interface.
8. The method for producing a polymer-dispersed liquid crystal display device according to item 7. 49. The method according to claim 47, wherein the polymerizable monomer is a liquid crystal monomer. 50. The method according to claim 47, wherein the pair of substrates is not subjected to a rubbing process. 51. The polymer dispersion type according to claim 47, wherein at least one of the pair of substrates is subjected to rubbing treatment in a plurality of directions. A method for manufacturing a liquid crystal display element. 52. The polymer-dispersed liquid crystal according to claim 47, wherein fine irregularities are formed on at least one of the pair of substrates. A method for manufacturing a display element. 53. The liquid crystal droplet according to claim 1, wherein a dichroic dye is mixed in addition to the liquid crystal.
45. The polymer-dispersed liquid crystal display device according to any one of 18 to 21, 32 to 37, and 40 to 44.