JPH10147783A - Liquid crystal material and production of liquid crystal optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the charge retentivity and high-temperature scattering performances of a liquid crystal optical element. SOLUTION: A liquid crystal material prepared by mixing a liquid crystal material base with a polymer-forming material, the first polymerization initiator lowly compatible with the base and the second polymerization initiator highly compatible with the base is placed in an arbitrary sealing space. When the liquid crystal material is irradiated with the first light at a wavelength in the light absorption wavelength region BW of the first polymerization initiator, the polymer-forming material is polymerized, while the low-molecular-weight material in the polymer-forming material is penetrated into the base. When the liquid crystal material is irradiated with the second light at a wavelength in the light absorption region CW, the polymerization of the low-molecular-weight component penetrated into the base can be accomplished to lower the amount of the residues in the base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal material used as a material such as a polymer-dispersed liquid crystal and a method for manufacturing a liquid crystal optical element using the same.

[0002]

2. Description of the Related Art In recent years, many studies have been made on a liquid crystal optical element that switches between a scattering state and a transmission state by changing the refractive index of a liquid crystal as disclosed in Japanese Patent Application Laid-Open No. 60-252687.
Has attracted the attention of developers.

This liquid crystal optical element uses a polymer dispersed liquid crystal in which a nematic liquid crystal is dispersed and held in a polymer having a refractive index equivalent to that of liquid crystal molecules. Between the scattering state and the transmission state by changing the refractive index of the liquid crystal depending on the presence or absence of an electric field.

The liquid crystal optical element using the polymer-dispersed liquid crystal utilizes light scattering, so that it is not necessary to use a polarizing plate, and it is necessary to use a polarizing plate to obtain linearly polarized light. Element (for example, a twisted nematic type (hereinafter referred to as a TN type) liquid crystal optical element),
There is an advantage that a bright display with a wide viewing angle is possible. Further, a liquid crystal optical element such as a TN type needs to precisely control the alignment process and the distance between the upper and lower substrates, and there is a disadvantage that large-area display tends to cause display unevenness.
A liquid crystal optical element using a polymer-dispersed liquid crystal has the advantage that alignment treatment is not required, the distance between substrates is not strictly controlled, and a large-area liquid crystal optical element can be easily manufactured.

The polymer dispersion type liquid crystal used for the above-mentioned liquid crystal optical element can be produced by: a casting method in which a liquid crystal material body and a polymer are dissolved in a common solvent and then cast; An emulsification method in which the liquid crystal material itself is emulsified and then cast, a phase separation method in which a homogeneous solution of the liquid crystal material main body and the polymer-forming material is formed, phase-separated by polymerization, and then a phase separation structure is formed. However, a phase separation method that does not require a solvent is generally widely performed as a method suitable for manufacturing a display.

[0006]

The liquid crystal optical element using the polymer-dispersed liquid crystal has the above-mentioned advantages, namely,
Since a polarizing plate is not used, a brighter display with a wider viewing angle can be realized as compared with a liquid crystal optical element such as a TN type, but on the other hand, the performance is inferior in terms of charge retention characteristics.
When a polymer-dispersed liquid crystal is manufactured by a phase separation method, which is the most commonly used manufacturing method, the charge retention characteristics often decrease significantly.

[0007] The main cause of the decrease in the charge retention characteristics of the polymer dispersed liquid crystal produced by the phase separation method is that when the polymer-forming material and the liquid crystal are prepared in a uniform solution, the polymer is contained in the liquid crystal material itself. A part of the forming material (mainly the low molecular weight monomer material in the polymer forming material) is dissolved. Furthermore, the elution of the low molecular weight material into the liquid crystal material itself lowers the phase transition temperature (transition temperature from the isotropic phase to the nematic phase) of the liquid crystal material main body, which may cause deterioration of the scattering characteristics at high temperatures. Therefore, it was also inconvenient in this respect.

As one method of reducing unnecessary elutes in the liquid crystal material body, a method of increasing the light intensity during polymerization is considered. However, if the liquid crystal material itself is deteriorated by strong light and only the charge retention characteristics are obtained, In some cases, other characteristics such as the driving voltage are adversely affected, and the problem cannot be solved.

[0009]

Means for Solving the Problems The present inventor paid attention to the solubility (compatibility) of a polymerization initiator used for forming a polymer-dispersed liquid crystal and a liquid crystal material itself, and as a result of conducting many experiments, it was found that It has been found that the solubility (compatibility) between the polymerization initiator and the liquid crystal material itself is related to the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element using the molecular dispersion type liquid crystal.
Furthermore, it has been found that deterioration of the liquid crystal material main body due to light during polymerization can be minimized and efficiently performed by selectively using an ultraviolet absorber having good compatibility with the liquid crystal material main body.

Therefore, the present invention provides a liquid crystal material main body, a polymer-forming material, and a first liquid crystal material having low compatibility with the liquid crystal material main body.
And a second polymerization initiator having high compatibility with the liquid crystal material main body to constitute the liquid crystal material.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a liquid crystal material main body, a polymer-forming material, a first polymerization initiator having poor compatibility with the liquid crystal material main body, and a liquid crystal material. It is characterized by containing a second polymerization initiator having good compatibility with the main body, and has the following effects. That is, in the state of the liquid crystal material, the second polymerization initiator is driven out of the liquid crystal material main body and the first polymerization initiator is driven out of the liquid crystal material main body, and is dissolved in the polymer forming material. In this state, when the liquid crystal material is irradiated with a light ray in the light absorption wavelength region of the first polymerization initiator (hereinafter, referred to as a first light ray), the polymer-forming material is polymerized. At this time, a low molecular weight material such as a monomer material contained in the polymer forming material permeates into the liquid crystal material body. Subsequently,
When the liquid crystal material is irradiated with a light ray in the light absorption wavelength region of the second polymerization initiator (hereinafter, referred to as a second light ray), polymerization of a low molecular weight component such as a monomer material penetrating into the liquid crystal material body proceeds. I do. Thereby, the amount of the residue (low molecular weight component) in the liquid crystal material main body decreases.

According to a second aspect of the present invention, in the liquid crystal material according to the first aspect, the first polymerization initiator has a light absorption wavelength region of the liquid crystal material main body within its light absorption wavelength region. Are characterized by having wavelength ranges that do not overlap, and thus have the following effects. That is, if a light ray in a wavelength range that does not overlap with the light absorption wavelength range of the liquid crystal material within the light absorption wavelength range of the first polymerization initiator is selected as the first light beam, the first light beam causes There is almost no adverse optical effect on the material body.

According to a third aspect of the present invention, in the liquid crystal material according to the first or second aspect, the first polymerization initiator has a light absorption wavelength range of the second polymerization initiator. It is characterized in that it has a wavelength range that does not overlap with the light absorption wavelength range, thereby having the following effects. That is, if a light ray in a wavelength range that does not overlap with the light absorption wavelength area of the second polymerization initiator in the light absorption wavelength area of the first polymerization initiator is selected as the first light ray,
The first light beam hardly adversely affects the second polymerization initiator.

According to a fourth aspect of the present invention, there is provided the liquid crystal material according to any one of the first to third aspects, wherein the second polymerization initiator is provided within the light absorption wavelength region of the liquid crystal material itself. It is characterized in that it has a wavelength range that does not overlap with the light absorption wavelength range, thereby having the following effects. That is, if a light ray in a wavelength range within the light absorption wavelength range of the second polymerization initiator that does not overlap with the light absorption wavelength range of the liquid crystal material body is selected as the second light beam, the liquid crystal is produced by the second light beam. There is almost no adverse optical effect on the material body.

According to a fifth aspect of the present invention, there is provided the liquid crystal material according to any one of the first to fourth aspects, wherein the second polymerization initiator is provided in the light absorption wavelength region. It is characterized in that it has a wavelength range that does not overlap with the light absorption wavelength range of the initiator, and thus has the following effects. That is, if a light ray in a wavelength range that does not overlap with the light absorption wavelength area of the first polymerization initiator in the light absorption wavelength area of the second polymerization initiator is selected as the second light ray, the second light ray is obtained. The light rays hardly adversely affect the first polymerization initiator.

The invention according to claim 6 of the present invention is characterized in that the liquid crystal material according to any one of claims 1 to 5, further comprises a light absorber which is compatible with the liquid crystal material body. Which has the following effect. That is, after the light absorber is dissolved in the liquid crystal material main body, the first light beam is absorbed by the liquid crystal material main body and the second polymerization initiator,
The second light beam is prevented from being absorbed by the liquid crystal material body.

According to a seventh aspect of the present invention, in the liquid crystal material according to the sixth aspect, the light absorbing agent has a light absorption wavelength range of the first polymerization initiator within its light absorption wavelength range. It is characterized in that it has overlapping wavelength ranges, and thus has the following effects. That is,
As the first light beam, within the light absorption wavelength region of the light absorber,
If a light beam having a wavelength region overlapping with the light absorption wavelength region of the first polymerization initiator is selected, the absorption of the first light beam by the liquid crystal material body is efficiently suppressed.

According to an eighth aspect of the present invention, in the liquid crystal material according to the sixth or seventh aspect, the second polymerization initiator has a light absorption wavelength of the light absorber within its light absorption wavelength region. It is characterized in that it has a wavelength range that does not overlap with the region, thereby having the following effects. That is, if a light beam in a wavelength range that does not overlap with the light absorption wavelength region of the light absorber in the light absorption wavelength region of the second polymerization initiator is selected as the second light beam, the second light beam becomes a light beam. It will not be unnecessarily absorbed by the absorbent.

According to a ninth aspect of the present invention, there is provided a liquid crystal material main body, a polymer forming material, a first polymerization initiator having poor compatibility with the liquid crystal material main body, and a liquid crystal material main body. Disposing a liquid crystal material containing a second polymerization initiator having good compatibility in an arbitrary enclosed space; and providing the liquid crystal material with a first polymerization initiator in a light absorption wavelength region of the first polymerization initiator. And then irradiating the second polymerization initiator with a second light within the light absorption wavelength region of the second polymerization initiator, thereby forming a liquid crystal optical element manufacturing method. It has such an effect. That is, when the liquid crystal material is irradiated with the first light beam, the polymer-forming material polymerizes, and a low-molecular-weight material such as a monomer material included in the polymer-forming material penetrates into the liquid crystal material body. Subsequently, when the liquid crystal material is irradiated with a second light beam, polymerization of a low molecular weight component such as a monomer material that has penetrated into the liquid crystal material body proceeds. Thereby, the amount of the residue (low molecular weight component) in the liquid crystal material main body decreases.

According to a tenth aspect of the present invention, in the method for manufacturing a liquid crystal optical element according to the ninth aspect, the light of the liquid crystal material main body is included in the light absorption wavelength region as the first polymerization initiator. The one having a wavelength range that does not overlap with the absorption wavelength region is used, and the first light ray is within the light absorption wavelength region of the first polymerization initiator and does not overlap with the light absorption wavelength region of the liquid crystal material body. It is characterized by irradiating light rays in the wavelength range, thereby having the following effects.
That is, the first light beam hardly adversely affects the liquid crystal material main body.

According to an eleventh aspect of the present invention, in the method for manufacturing a liquid crystal optical element according to the ninth or tenth aspect, the second polymerization initiator is used as the first polymerization initiator in the light absorption wavelength region thereof. The one having a wavelength range that does not overlap with the light absorption wavelength region of the polymerization initiator is used, and the first light beam is within the light absorption wavelength region of the first polymerization initiator, and It is characterized by irradiating light rays in a wavelength range that does not overlap with the light absorption wavelength range, thereby having the following effects. That is, the first light beam causes the second
There is almost no optical adverse effect on the polymerization initiator.

According to a twelfth aspect of the present invention, in the method for manufacturing a liquid crystal optical element according to any one of the ninth to eleventh aspects, the second polymerization initiator is included in the light absorption wavelength region thereof. The light having a wavelength range that does not overlap with the light absorption wavelength region of the liquid crystal material body is used, and the second light ray is within the light absorption wavelength region of the second polymerization initiator, and the light absorption wavelength of the liquid crystal material body. It is characterized by irradiating light rays in a wavelength range that does not overlap with the region, thereby having the following effects. That is, the second light beam hardly exerts an adverse optical effect on the liquid crystal material body.

According to a thirteenth aspect of the present invention, in the method for manufacturing a liquid crystal optical element according to any one of the ninth to twelfth aspects, the second polymerization initiator has a light absorption wavelength range within the light absorption wavelength range. A light having a wavelength range that does not overlap with the light absorption wavelength region of the first polymerization initiator is used, and the second light beam is within the light absorption wavelength region of the second polymerization initiator, and It is characterized by irradiating light in a wavelength range that does not overlap with the light absorption wavelength range of the initiator, thereby having the following effects. That is, the second light beam hardly adversely affects the first polymerization initiator.

According to a fourteenth aspect of the present invention, there is provided a method of manufacturing a liquid crystal optical element according to any one of the first to thirteenth aspects, wherein the light absorbing agent having compatibility with the liquid crystal material body as the liquid crystal material. Is further characterized by having the following effects. That is, the light-absorbing agent dissolves into the liquid crystal material main body, and then the first light beam is absorbed by the liquid crystal material main body and the second polymerization initiator, and the second light beam is absorbed by the liquid crystal material main body. Suppress absorption.

According to a fifteenth aspect of the present invention, in the method for manufacturing a liquid crystal optical element according to the fourteenth aspect, the light of the first polymerization initiator is included in the light absorption wavelength region as a light absorber. The one having a wavelength region overlapping with the absorption wavelength region is used, and the first light beam is within the light absorption wavelength region of the light absorber and overlaps with the light absorption wavelength region of the first polymerization initiator. Are characterized by the use of the above-described light beam, thereby having the following effects. That is, the light absorber efficiently suppresses the absorption of the first light beam by the second polymerization initiator or the liquid crystal material main body.

According to a sixteenth aspect of the present invention, in the method for manufacturing a liquid crystal optical element according to the fourteenth or fifteenth aspect, a light absorbing agent is included in the light absorption wavelength region as a second polymerization initiator. A light having a wavelength range that does not overlap with the light absorption wavelength region of the second polymerization initiator is used as the second light beam, and overlaps with the light absorption wavelength region of the light absorber. It is characterized by irradiating a light beam in a wavelength range that does not occur, thereby having the following effects. That is, the second light beam is not unnecessarily absorbed by the light absorber.

The first and second polymerization initiators include:
It should be selected according to the compatibility of the liquid crystal material itself, and Darocure 1173 and Darocure manufactured by Cibagaiki Co., Ltd.
It can be composed of commercially available products such as 4265, Irgacure184, and Irgacure651.

The light absorbing agent may be selected according to the compatibility with the liquid crystal material itself and the light absorption wavelength range, and may be composed of generally commercially available products such as salicylic acid derivatives and benzophenone derivatives.

Further, the polymer-forming material is not particularly limited, as long as the oligomer or monomer, which is the material for forming the matrix, can be polymerized by light or heat in the presence of a polymerization initiator. Is generally commercially available such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, neopentyl glycol acrylate, hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, etc. Acrylic monomers and, more broadly, non-acrylic commercial products can also be used. As an oligomer material contained in the polymer-forming material, polyurethane acrylate, polyester acrylate, epoxy acrylate, or the like can be used.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a liquid crystal optical element manufactured using the liquid crystal material of the present invention.

This liquid crystal optical element includes a pair of glass substrates 1 and 2 on which a transparent electrode layer 3 made of indium tin oxide and an insulating film 4 are sequentially laminated. The glass substrates 1 and 2 oppose each other with the transparent electrode layers 3 spaced apart from each other by a predetermined distance.
A polymer-dispersed liquid crystal 5 is provided. The polymer-dispersed liquid crystal 5 is configured by dispersing and holding a liquid crystal 7 in a polymer matrix 6. The polymer-dispersed liquid crystal 5 is sealed between the transparent electrode layers 3 and 3 by a spacer and seal resin 8 arranged on the periphery of the substrates 1 and 2.

First Embodiment Next, a first embodiment of the method for manufacturing the above-described liquid crystal optical element will be described with reference to FIG.

A pair of glass substrates 1 and 2 on which a transparent electrode layer 3 made of indium / tin oxide and an insulating film 4 are formed are prepared, and one glass substrate (the lower glass substrate in the figure).
A spacer / seal resin 8 made of an acid anhydride-curable epoxy resin in which glass fibers having a diameter of 13 μm are dispersed is printed and formed in a predetermined shape (for example, a square frame shape having a rectangular cross section) so as to cover the entire periphery of the peripheral edge of No. 2. At this time, an opening 9 is formed in the spacer / seal resin 8.

The other glass substrate 1 is made to face the glass substrate 2 on which the spacer / seal resin 8 is formed.
By heating for a time, the spacer and seal resin 8 is cured, and the glass substrates 1 and 2 are bonded. Thus, the empty cell 10 is completed.

Next, a liquid crystal material body 20 _1, a polymer-forming material 21 _1, the first and the polymerization initiator 22 ₁ Poor compatibility with the liquid crystal material body 20 _1, to the liquid crystal material body 20 ₁ mixing the ₁ good second initiator 23 compatibility Te providing a liquid crystal material 24 ₁ in which a.

The liquid crystal material body 20 ₁ is used 8.200g of tolane liquid crystal material. The polymer-forming material 21 is lauryl acrylate (for example, Kyoeisha Yushi Kagaku Kogyo Co., Ltd.)
0.954 g of a polymer-forming monomer consisting of
100 (trade name: manufactured by Toa Gosei Chemical Industry Co., Ltd.) mixed with 0.808 g of an oligomer is used. First polymerization initiator 22 _1, 2,2-dimethoxy-2-phenyl - acetophenone (Irgacure 651 (trade name): Chibagaiki Corporation) is used 0.019 g. The second polymerization initiator 23 ₁ was 0.019 g of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TMOPO).
Used.

The first, determination criteria used in defining a second weight initiator 22 _1, 23 ₁ of properties, i.e., explaining the criteria for good or bad compatibility with a liquid crystal material body 20 _1. Whether the compatibility is good or bad can be determined by comparing the solubility parameters of the substances with each other. The solubility parameter of a polymer compound can be measured by adding a non-solvent to a polymer compound dissolved in a solvent and observing a point where turbidity starts, but a polymer having relatively few hydrogen bonds can be measured. If it is a compound, for example, it can be calculated by the following formula.

SP = ρΣG / M ... SP: dissolution parameter ρ: density of polymer compound G: cohesive energy constant M: molecular weight of basic molecule constituting polymer compound The compatibility was determined in this way. Using the dissolution parameters, it can be defined as follows. That is, the solubility parameter of the first material and SP _1, when the solubility parameter of the second material and SP _2, if the following equation is satisfied, the second material, the first material It can be said that the compatibility is good.

SP ₂ -1 ≦ SP ₁ ≦ SP ₂ +1 Similarly, if the following equation is satisfied, it can be said that the second substance has poor compatibility with the first substance.

[0041] SP ₂ <SP ₁ -1 or _{SP 2,> SP 1 + 1} ... 2,2- dimethoxy-2-phenyl - acetophenone (Ir
The dissolution parameter of the _first polymerization initiator 221 composed of gacure651 (trade name, manufactured by Ciba Gaiki Co., Ltd.) was calculated to be about 8.0 by the above formula, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TMOPO) was used. ) second solubility parameter of the polymerization initiator 23 ₁ made of is calculated to be about 9.7 in the same manner.

In the present embodiment, as the liquid crystal material body,
And selects the liquid crystal material body 20 ₁ consisting of the solubility parameter of about 9.8 tolane liquid crystal material, first, second weight initiator 22 _1, 23 ₁ are selected as described above based on this. Therefore, assuming that the liquid crystal material body 201 is a _first substance and the first and second polymerization initiators 22 ₁ and 23 ₁ are a second substance, the first polymerization initiator 22 ₁ is
0 satisfy the above formula can be confirmed for _one. That is, the first initiator 22 ₁ can be defined as the poor compatibility with respect to the liquid crystal material body 20 _1. Second polymerization initiator 23
_It can be confirmed that ₁ satisfies the above expression with respect to the liquid crystal material body 201. That is, the second initiator 23 ₁ can be defined with good compatibility to the liquid crystal material body 20 _1.

Further, the liquid crystal material body 20 ₁ , the first
The light absorption wavelength regions of the polymerization initiator 22 ₁ and the second polymerization initiator 23 ₁ will be described with reference to FIG. FIG.
In the graph, the horizontal axis represents the wavelength (the wavelength increases as going to the right), and the vertical axis represents the absorption intensity. In the figure, symbol A is a light absorption spectrum of the liquid crystal material body 20 _1, reference numeral A _W is a light absorption wavelength region of the liquid crystal material body 20 _1. Symbol B, poor compatibility with respect to the liquid crystal material body 20 ₁ first polymerization initiator 2
A 2 ₁ optical absorption spectrum, code B _W is a light absorption wavelength region of the first polymerization initiator 22 _1. Symbol C, good compatibility with the liquid crystal material body 20 ₁ second polymerization initiator 2
3 is a _first light absorption spectrum, code C _W is a second polymerization initiator 23 ₁ of the light absorption wavelength region.

As it is apparent from this figure, the liquid crystal material body 20 ₁ of the light absorption wavelength region A _W is the shortest wavelength side. First
The light absorption wavelength region B _W of the polymerization initiator 22 ₁ Although intersects the light absorption wavelength region A _W, has a wavelength range B _WL extending from the longer wavelength side light absorption wavelength region A _W . Second light absorption wavelength region C _W of the polymerization initiator 23 ₁ light absorption wavelength region A _W, but intersects the B _W, these light absorption wavelength region A _W, further extending the long wavelength side of B _W Wavelength region _CWL .

The second polymerization initiator 22 ₁ of the light absorption wavelength region C _W has, in its wavelength region center, absorbs almost impossible wavelength region D _W by a second polymerization initiator 23 ₁ is present. The wavelength range D _W is substantially the same as the wavelength range B _WL of the light absorption wavelength range B _W.

Each of the light absorption wavelength ranges A _W , B _W , C
_W is a quartz cell gap 13 .mu.m, a result of measurement in a state in which the liquid crystal material body 20 ₁ described above, the first initiator 22 _1, and a second polymerization initiator 23 ₁ were respectively filled, light The long wavelength side end _AWe of the absorption wavelength region _AW is 3
30 nm, light absorption wavelength region _BW , long wavelength side end B
_We is 360 nm, and the long wavelength side end C _We of the light absorption wavelength region C _W is 410 nm.

Accordingly, each of the long wavelength side ends A _We , B _we ,
C _we has a relationship of A _We <B _we <C _we , and the wavelength range B _WL
Is in the range of 330 to 360 nm, and the wavelength range C _WL is 36.
The range is from 0 to 410 nm.

[0048] Each light absorption wavelength region A _W, B _W, since C _W is set in this way, is irradiated with light in a wavelength range B _WL to the liquid crystal material 24 _1, the light beam a second polymerization almost without being absorbed by the initiator 23 ₁ and the liquid crystal material body 20 _1,
It is selectively absorbed only by the first polymerization initiator 22 ₁ . Moreover, when irradiated with light of a wavelength range C _WL to the liquid crystal material 24 _1, the light beam is almost without being absorbed in the first polymerization initiator 22 ₁ and the liquid crystal material body 20 _1, a second polymerization initiator 23 is selectively absorbed ₁ only.

The liquid crystal material body 2 having the above characteristics
The liquid crystal material 24 ₁ obtained by mixing O ₁ , the first polymerization initiator 22 ₁ , and the second polymerization initiator 23 ₁ is sufficiently stirred at 20 ° C. Then, while the liquid crystal material body 20 polymerization initiator 23 ₁ Good compatibility second relative ₁ seep into the liquid crystal material body 20 _1, polymerization compatibility first bad with respect to the liquid crystal material body 20 ₁ initiator 22 _1, outside of the liquid crystal material body 20 _1, i.e., seep into the polymeric material for forming 21.

Further, the sufficiently stirred liquid crystal material 24 ₁ is
While maintaining the temperature of 20 ° C., open cell 1
Inject at 0. After injecting the liquid crystal material 24 ₁ , the opening 9
Is sealed.

[0051] Then, the liquid crystal material 24 of _the empty cell 10, while maintaining the temperature of 20 ° C., about 25m a first light beam is ultraviolet light of 350nm in wavelength region B _WL
With at W / cm ² was irradiated for 100 seconds, carrying out the polymerization of the liquid crystal material 24 _1. Then, first, the polymer-forming material 21 in which the _first polymerization initiator 22 ₁ is unevenly distributed is converted into the first polymerization initiator 2
Polymerized by the action of 2 _1. At this time, since the wavelength range B _WL is the wavelength region which does not overlap with the light absorption wavelength region A _W, C _W, the first light beam within the wavelength range B _WL liquid crystal material body 20 ₁ and the second polymer It will not be absorbed by the initiator 23 _1.

[0052] The irradiation of the first light beam, a low molecular weight materials such as monomeric materials in the polymer forming material 21 penetrates into the liquid crystal material body 20 ₁ is driven out of the polymer-forming material 21.

[0053] Thus, the liquid crystal material body 20 _1, so that _{the first} and second polymerization initiator 23 and a low molecular weight material is unevenly distributed.

[0054] Subsequently, the liquid crystal material of the air cell 10 is subjected to light annealing by irradiating 30 seconds with the second light beam is ultraviolet light of 400nm in wavelength range C _WL at about 3 mW / cm ² . Then, the polymerization proceeds in low molecular weight material remaining in the liquid crystal material body 20 _1, a low molecular weight material is a residue of the liquid crystal material body 20 in ₁ almost eliminated. At this time, the wavelength range C _WL light absorption wavelength region A _W, since the B _W is a wavelength region that does not overlap the second light beam within the wavelength range C _WL liquid crystal material body 20 ₁ and the first polymer It will not be absorbed by the initiator 22 _1. Thus, a liquid crystal optical element composed of a polymer dispersed liquid crystal is completed.

[0055] As described above, when producing a liquid crystal optical element, almost no residual materials such as low-molecular material from the liquid crystal material body 20 _1, whereby electrification retention characteristics are improved.

Further, the phase transition temperature (the phase transition temperature from the isotropic phase to the nematic phase) is improved, and the deterioration of the scattering characteristics at high temperatures is reduced.

Second Embodiment The manufacturing method of this embodiment is different from the liquid crystal material 241 of the _first embodiment in that the second polymerization initiator is different but the other constituents are the same. with 24 _2, since more fabrication steps are also the same as the first embodiment, is attached to them will be omitted.

[0058] In the liquid crystal material 24 ₂ in this embodiment, as the liquid crystal material good compatibility with respect to the main body 20 _1, and a second polymerization initiator light absorption characteristic is the same as in the first embodiment, 2-, a polymerization initiator having a solubility parameter of about 8.7
Darocure 4265 (trade name) manufactured by Cibagaiki Co., Ltd., which is an equivalent mixture of hydroxy-2-methyl-1phenylpropan-1-one and a diphenylphosphine oxide derivative as a polymerization initiator having a solubility parameter of about 10.2. The polymerization initiator 232 of No. ₂ was used in an amount of 0.019 g.

Third Embodiment In the manufacturing method of the third embodiment, the same liquid crystal material as that of the liquid crystal material 241 of the _first embodiment is used for the other constituent substances, although the second polymerization initiator is different. with 24 _3, since more production method also is the same as the first embodiment, is attached to them will be omitted.

[0060] In the liquid crystal material 24 ₃ of this embodiment has good compatibility with the liquid crystal material body 20 _1, and, as a second initiator light absorption characteristic is the same as in the first embodiment , A polymerization initiator having a solubility parameter of about 8.7
Darocure 1700 (trade name) manufactured by Ciba Gaiki Co., Ltd., which is an equivalent mixture of -hydroxy-2-methyl-1 phenylpropan-1-one and a diphenylphosphine oxide derivative which is a polymerization initiator having a solubility parameter of about 9.7. the second polymerization initiator 23 ₃ using 0.038 g.

Fourth Embodiment In this embodiment, a liquid crystal material 24 _{4 having the} following structure is used.
Is used.

That is, unlike the first embodiment, a dissolution parameter of about 9.
Liquid crystal material body 20 composed of a tolan-based liquid crystal material having
₂ to 8.200 g (the liquid crystal material body 2 of the first embodiment)
The solubility parameter of O ₁ is about 9.8), and the same polymer-forming material 21 as in the first embodiment is 1.7.
62 g, unlike the same first initiator 22 ₁ 0.019 g, & first embodiment and the first embodiment,, the solubility parameter of about 8.
2-hydroxy-2-methyl-1 as a polymerization initiator of No. 7
Phenylpropan 1-one and solubility parameter about 10.2
Darocure 4265 manufactured by Cibagaiki Co., Ltd., which is an equal mixture with a polymerization initiator diphenylphosphine oxide derivative of
(Trade name), a second polymerization initiator 2 having good compatibility with the liquid crystal material body and similar optical characteristics.
3 ₄ have 0.019 g, a-solubility parameter of about 8.7 and above good compatibility with the liquid crystal material body 20 _2, and the maximum absorption wavelength region E _WT is 330～370Nm 2, and a liquid crystal material 24 ₄ UV absorber 25 ₁ consisting of 2'-dihydroxy-4-methoxybenzophenone by mixing 0.05 g, more than ones.

Next, the light absorption wavelength region of the respective materials constituting the liquid crystal material 24 ₄ will be described with reference to FIG. In FIG. 4, the horizontal axis represents wavelength (the longer wavelength goes to the right), and the vertical axis represents absorption intensity. In the figure, reference numeral A 'is a light absorption spectrum of the liquid crystal material body _{20. 2,} reference numeral A _W' is a light absorption wavelength region of the liquid crystal material body 20 _2. Sign B '
Is a light absorption spectrum of the liquid crystal material body 20 poor compatibility with respect to ₂ first polymerization initiator 22 _1, reference numeral B _W 'is a light absorption wavelength region of the first polymerization initiator 22 _1. Code C 'is a light absorption spectrum of the liquid crystal material body 20 good compatibility with respect to ₂ second polymerization initiator 23 _4, reference numeral C _W'
Is a light absorption wavelength region of the second polymerization initiator 23 _4. Symbol E is a light absorption spectrum of the ultraviolet absorber 25 ₁ ,
E _W is the light absorption wavelength region of the ultraviolet absorber 25 ₁ .

[0064] As is apparent from this figure, the liquid crystal material body 20 _{and second} light absorption wavelength region A _W 'is in the shortest wavelength side. Although the first polymerization initiator 22 ₁ of the light absorption wavelength region B _W 'is a light absorption wavelength region A _W' intersects the wavelength range B _WL extending to the longer wavelength side than the light absorption wavelength region A _W ''have. The second polymerization initiator 23 ₄ of the light absorption wavelength region C _W 'is a light absorption wavelength region A _W', but intersects the B _W ', these light absorption wavelength region A _W, a longer wavelength side of B _W The wavelength region C _WL ′ extends to

[0065] The second polymerization initiator 22 ₄ of the light absorption wavelength region C _W 'has on its wavelength region center, the second initiator 23 ₄
Therefore, there is a wavelength range D _W ′ that can hardly be absorbed. The wavelength range D _W ′ is the wavelength range B of the light absorption wavelength range B _W ′.
_The wavelength range is almost the same as _WL '.

[0066] Light absorption wavelength region E _W UV absorber 25 ₁ is present over the wavelength range B _WL '. Furthermore, of the light absorption wavelength region E _W , the maximum absorption wavelength region E _WT that is the wavelength region that absorbs light the most also covers the wavelength region B _WL ′. Also,
Although the wavelength region E _W and the wavelength region C _WL ′ intersect,
The wavelength region C _WL ′ extends to the longer wavelength side, and the wavelength region C _WL ′ has a wavelength region _W that is not included in the wavelength region E _W.

Note that each light absorption wavelength region A _W ′, B _W ′, C
_{W'E W} and maximum absorption wavelength range E _WT have a gap of 13 μm
The quartz cell, the liquid crystal material body 20 ₁ described above, a first polymerization initiator 22 _1, as a result of the second polymerization initiator 23 _4, and an ultraviolet absorbent 25 ₁ was measured in a state of being filled, respectively, 'long wavelength edge a _We of' light absorption wavelength region a _W is 330 nm, 'long wavelength edge B _We of' light absorption wavelength region B _W is 360 nm, the light absorption wavelength region E _W length The wavelength side end E _WE is 370 nm, and the light absorption wavelength region C
The long wavelength side end C _We ′ of _W ′ is 410 nm. Thus, the long wavelength end _{A We ', B we',} ' the E _We, A _We' C _we have relationships _{<B we '<E WE <} C we', the wavelength range B _WL '330 ３360 nm, and the wavelength range C
_WL ′ is in the range of 360 to 410 nm, and the wavelength range W is 3
The range is 70 to 410 nm. Also, an ultraviolet absorber 2
5 ₁ of maximum absorbance wavelength region E _WT is 330～370Nm.

Each light absorption wavelength region A _W ′, B _W ′, C _W ′,
Since E _W (E _WT) is set in this way, is irradiated with light in a wavelength range B _WL 'to the liquid crystal material 24 _4, the beam second polymerization initiator 23 ₄ and a liquid crystal material body 20 ₂ is hardly absorbed, and is selectively absorbed only by the first polymerization initiator 22 ₁ . Further, the wavelength range C _WL '(in particular, a wavelength range W) to the liquid crystal material 24 ₄ when irradiated with light of,
Its beam first polymerization initiator 22 ₁ and the liquid crystal material body 20 ₂
Almost without being absorbed, it is selectively absorbed by the second polymerization initiator 23 _4.

[0069] or more properties of the liquid crystal material 24 ₄ composed of the material having a sufficiently stirred at 20 ° C.. Then, while the liquid crystal material body 20 and the second initiator 23 ₄ and an ultraviolet absorbent 25 ₁ Good each compatibility with the ₂ dissolve out into the liquid crystal material body 20 _2, the phase relative to the liquid crystal material body 20 ₂ the first polymerization initiator 22 ₁ poor solubility, the liquid crystal material body 2
It melts out of O ₂ , that is, into the polymer-forming material 21.

Next, the liquid crystal material is injected into the empty cell 10 through the opening 9 while maintaining the temperature of 20 ° C.
Is sealed. The first light beam irradiated 100 seconds with at about 25 mW / cm ² is ultraviolet light 350nm in wavelength region B _WL ', carry out the polymerization of the liquid crystal material 24 _4. Then, first, polymeric forming material 21 in which the first polymerization initiator 22 ₁ are unevenly distributed is polymerized by a first action of the polymerization initiator 22 _1. In this case, 'because as the wavelength region which does not overlap, the wavelength range B _WL' wavelength band B _WL 'light absorption wavelength region A _W', C _W first ray within the Ya crystal material body 20 ₂ It will not be absorbed by the second polymerization initiator 23 _4.

[0071] However, depending on the optical properties of the second polymerization initiator 23 _4, in the wavelength range D _W ', which may have a more or less light absorption characteristics. In such a case, there is a possibility that the first light beam is absorbed by the second polymerization initiator 23 _4. Even in this case, good compatibility with the liquid crystal material body 20 _2, moreover UV absorber 25 ₁ having an absorption wavelength region E _WT covering the wavelength range D _W '
There to be contained in the liquid crystal material 24 _4, it has the following advantages. That is, 'when irradiated with ultraviolet light, in the liquid crystal material body 20 _2, the wavelength range B _WL' wavelength range B _WL rays is absorbed by the ultraviolet absorbent 25 ₁ the influence of light the second polymerization initiator rarely up to 23 _4.

[0072] Further, by containing the ultraviolet absorber 25 _1, there is also further advantages as follows. That is, the band of the ultraviolet light to be irradiated as light within the wavelength range B _WL ′ may slightly extend beyond the wavelength range B _WL ′ depending on the irradiation accuracy of the irradiation unit.

[0073] In this case, particularly, when had spread to the short wavelength side, the light is gone is absorbed by the liquid crystal material body 20 _2, could cause such an adverse effect on the liquid crystal material body 20 ₂ . However, the band of the light absorption wavelength region E _W (ultraviolet absorber 25 ₁ ) covering the wavelength region B _WL ′ is wider than the wavelength region D _W ′, and the light absorption wavelength region E _W
Short wavelength edge E _WS of the 'long wavelength edge A _WE' light absorption wavelength region A _W intersects a. Therefore, even when the band of the ultraviolet light to be irradiated as light in the wavelength region D _W ′ is slightly extended beyond the wavelength region D _W ′ to the short wavelength side due to the irradiation accuracy of the irradiation unit or the like, light of shorter wavelength is absorbed by the ultraviolet absorbing agent 25 _1, less likely to be absorbed by the liquid crystal material body 20 _2. Therefore, even such light as the irradiation as a first light beam, to cause an adverse effect on the liquid crystal material body 20 ₂ hardly.

[0074] After that, subsequently, the liquid crystal material 24 ₄ empty cell 10, a second polymerization initiator 23 ₄ of the light absorption wavelength region C _W, the light absorption wavelength region of the ultraviolet absorber 25 ₁ A second light beam of 400 nm ultraviolet light in a wavelength range W which does not overlap with E _W is applied at a rate of about 3 mW / cm ^2.
Light annealing is performed by irradiating for 0 second. Then, the polymerization proceeds in low molecular weight material remaining in the liquid crystal material body 24 in _4, low molecular weight material is a residue of the liquid crystal material body 24 in ₄ almost eliminated. At this time, the wavelength range W light absorption wavelength region A _W ', B _W' because as the wavelength region which does not overlap the second light beam within the wavelength range W the liquid crystal material body 20 ₂ and the first polymerization It will not be absorbed by the initiator 22 _1.

[0075] Further, a wavelength band W which does not overlap the light absorption wavelength region E _W UV absorber 25 ₁ 400n
For use ultraviolet light of m, the ultraviolet light will not be absorbed by the ultraviolet absorbent 25 _1. Therefore, ultraviolet light is absorbed by the ultraviolet absorbent 25 _1, also it does not occur that such polymerization of a low molecular material becomes insufficient.

As described above, a liquid crystal optical element composed of a polymer dispersed liquid crystal is completed.

[0077] manufacturing method of the fifth embodiment this embodiment, although the UV absorber is different that the other constituents, the same liquid crystal material 24 ₅ and the liquid crystal material 24 ₄ of the fourth embodiment Since the use and the manufacturing procedure are the same as those of the fourth embodiment, the description thereof will be omitted.

[0078] In the liquid crystal material 24 ₅ of this embodiment has good compatibility with the liquid crystal material body 20 _2, and as an ultraviolet absorber which is light-absorbing properties the same as in the fourth embodiment, the solubility parameter of about 8.8, maximum absorption wavelength range E _WT 28
0~370nm UV absorber 25 ₂ consisting of 2,4-dibenzoyl resorcinol is (measured by filling a quartz cell gap 13 .mu.m) was used 0.038 g.

Sixth Embodiment The manufacturing method of this embodiment uses the same liquid crystal material 25 ₆ as the liquid crystal material 24 _{4 of the fourth} embodiment except that the second polymerization initiator is different. Since the use and the manufacturing procedure are the same as those of the fourth embodiment, the description thereof will be omitted.

[0080] In the liquid crystal material 24 ₆ of this embodiment, good compatibility with the liquid crystal material body 20 _2, and a second polymerization initiator light absorption properties it is also the same as in the fourth embodiment, 2-, a polymerization initiator having a solubility parameter of about 8.7
An equimolar mixture of hydroxy-2-methyl-1phenylpropan-1-one and a diphenylphosphine oxide derivative which is a polymerization initiator having a solubility parameter of about 9.7,
And the long wavelength side end E _{We of the} light absorption wavelength region C _W ′ is about 420
nm a second polymerization initiator 23 ₅ consisting of a (measured by filling a quartz cell gap 13 .mu.m) Chibagaiki Co., Ltd. Darocure1700 (trade name) was used 0.038 g.

[0081] manufacturing method of the seventh embodiment This embodiment of, although the second polymerization initiator are different, for the rest, the liquid crystal material 24 equivalent to ₄ liquid crystal material 24 ₇ of the fourth embodiment Since the use and the manufacturing procedure are the same as those of the fourth embodiment, the description thereof will be omitted.

[0082] In the liquid crystal material 24 ₇ of this embodiment has good compatibility with the liquid crystal material body 20 _2, and a second polymerization initiator light absorption properties are also the same as in the fourth embodiment, Dissolution parameter about 9.7, light absorption wavelength region C _W '
Long wavelength edge C _We 'about 410nm of (gap 13μ
2,4,6-trimethylbenzoyldiphenylphosphine oxide (TM)
The second polymerization initiator 23 ₆ consisting of OPO) 0.038
g used.

As a comparative example of the first to third embodiments,
A liquid crystal optical element composed of a polymer dispersed liquid crystal was prepared by the liquid crystal material and the manufacturing method of Comparative Examples 1 and 2 below.

[0084] Comparative Example 1 This comparative example, although the polymerization initiator is different that the other, using the first embodiment the same liquid crystal material 25 _A and the liquid crystal material 24 _1, further manufacturing procedure also first Since it is the same as the embodiment, the description thereof is omitted.

[0085] This comparative example, a polymerization initiator (see first initiator 22 ₁ of the first embodiment) poor compatibility Irgacure651 the liquid crystal material body as only, such polymerization initiator agent and the liquid crystal material 25 _a contains 0.038g of. Regarding the light absorption characteristics of Irgacure651, see Fig. 3,
Reference is made to symbols A and A ′ in FIG.

Comparative Example 2 This comparative example uses the same liquid crystal material 25 _B as the liquid crystal material 241 of the _first embodiment except for the polymerization initiator, and the manufacturing procedure is also the same as that of the _first embodiment. Since it is the same as the embodiment, the description thereof is omitted.

In this comparative example, the polymerization initiator was a combination of two polymerization initiators having poor compatibility with the liquid crystal material body. That, · Irgacure 651 consists (see first initiator 22 ₁ of the first embodiment), the liquid crystal material body (solubility parameter 9.8) poor compatibility with the first polymerization initiator 0 .
A second polymerization initiator which is composed of Darocure 1173 (trade name: having a dissolution parameter of about 8.8) manufactured by Ciba Gaiki Co., Ltd., and having poor compatibility with the liquid crystal material body (dissolution parameter: 9.8) And 0.019 g together to constitute a polymerization initiator.

As a comparative example of the fourth to seventh embodiments,
A liquid crystal optical element made of a polymer dispersed liquid crystal was prepared by the liquid crystal materials and the production methods of Comparative Examples 3 to 7 below.

Comparative Example 3 This comparative example uses the same liquid crystal material 25 _C as the liquid crystal material 244 of the _fourth embodiment, except that the polymerization initiator is different. Since it is the same as the embodiment, the description thereof is omitted.

[0090] This comparative example, a polymerization initiator (see polymerization initiator 22 ₁ of the first embodiment) poor Irgacure651 compatibility with the liquid crystal material body and only such polymerization initiator 0 and a liquid crystal material 25 _C contains .038G. 3 and 4 show the light absorption characteristics of Irgacure651.
Reference signs A and A ′.

[0091] Comparative Example 4 This comparative example, although the polymerization initiator is different that the other, using the fourth liquid crystal material 24 ₄ same liquid crystal material as 25 _D of the embodiment of the further manufacturing procedure also in the fourth Since it is the same as the embodiment, the description thereof is omitted.

In this comparative example, the polymerization initiator was a combination of two polymerization initiators having poor compatibility with the liquid crystal material body. That, · Irgacure 651 consists (see first initiator 22 ₁ of the first embodiment), the liquid crystal material body (solubility parameter 9.8) poor compatibility with the first polymerization initiator 0 .
A second polymerization initiator which is composed of Darocure 1173 (trade name: having a dissolution parameter of about 8.8) manufactured by Ciba Gaiki Co., Ltd., and having poor compatibility with the liquid crystal material body (dissolution parameter: 9.8) And 0.019 g together to constitute a polymerization initiator.

Comparative Example 5 This comparative example differs from the fifth embodiment only in that no ultraviolet absorber is added, and in other respects, the same liquid crystal material 25 _E as the liquid crystal material 244 of the _fourth embodiment is used. Since the use and the manufacturing procedure are the same as those of the fourth embodiment, the description thereof is omitted.

Comparative Example 6 This comparative example uses the same liquid crystal material 25 _F as the liquid crystal material 244 of the _fourth embodiment except that the ultraviolet absorber is different. Since it is the same as the embodiment, the description thereof is omitted. In the following description, the same parts that are not the same as those in the fourth embodiment are denoted by the same reference numerals.

[0095] This comparative example, as an ultraviolet absorber, a maximum absorption wavelength region E _WT 'is a 280～340Nm, first initiator 22 _first wavelength band B _WL' (330~360
liquid crystal material 25 _{F including an} ultraviolet absorber composed of 2,4-dihydroxybenzophenone that cannot cover
Was configured.

COMPARATIVE EXAMPLE 7 This comparative example uses the same liquid crystal material 25 _G as the liquid crystal material 244 of the _fourth embodiment, except that the ultraviolet absorber is different. Since it is the same as the embodiment, the description thereof is omitted. In the following description, the same parts that are not the same as those in the fourth embodiment are denoted by the same reference numerals.

This comparative example has poor compatibility (solubility parameter 7.8) with the liquid crystal material body 20 ₂ (solubility parameter 9.2) as an ultraviolet absorber, and has a maximum absorption wavelength region E _WT '. there a 320 to 380 nm, the wavelength range of the first polymerization initiator 22 ₁ B _WL '(330~360n
m) a liquid crystal material 25 containing an ultraviolet absorber consisting of 5-chloro-2-hydroxybenzophenone which cannot cover
_G configured.

A liquid crystal optical element made of a polymer dispersed liquid crystal manufactured by the manufacturing method of the first to seventh embodiments, and a comparative example 1
The liquid crystal optical elements made of polymer dispersed liquid crystals manufactured by the manufacturing methods of Nos. 7 to 7 were compared as follows.

That is, as shown in FIG. 5A, a xenon lamp 50 and a luminance meter 51 are arranged facing each other, and a shutter 52 is arranged between them. And
The luminance I ₀ when the light incident on the luminance meter 51 via the shutter 52 is blocked is measured.

[0100] Further, as shown in FIG. 5 (b), in a state of detaching the shutter 52, to measure the luminance I _MAX when all light from the xenon lamp 50 is incident on luminance meter 51.

After measuring the luminances I ₀ and I _MAX in this manner, the liquid crystal optical element S is disposed at a predetermined position between the xenon lamp 50 and the luminance meter 51 as shown in FIG. and the luminance I _S of light passing through the liquid crystal optical element S of the field-free state is measured with a luminance meter 51.

Then, each luminance I measured in this way is
_{Based on 0} , I _MAX , and I _S , a minimum transmittance T _min (%) was calculated by the following equation, and the value (minimum transmittance) was used as an index of scattering.

T _min (%) = I _S / (I _MAX −I ₀ ) × 100... According to this evaluation, the liquid crystal optical element having a better scattering property has a smaller minimum transmittance T _min (%). .

Table 1 below shows the values of the minimum transmittance T _min (%) at each temperature of the liquid crystal optical element manufactured by the manufacturing method of each embodiment and each comparative example.

[0105]

[Table 1]

As is clear from this table, Comparative Examples 1 and 2
In the liquid crystal optical element manufactured by the method of the first embodiment, the minimum transmittance T _min deteriorates as the temperature rises, whereas the liquid crystal optical element manufactured by the manufacturing method of the first to third embodiments It can be seen that the minimum transmittance T _min hardly deteriorates even when the temperature rises, that is, the deterioration of the scattering at high temperatures is suppressed.

Similarly, in Comparative Examples 3 to 7, the minimum transmittance T _min deteriorates as the temperature increases, whereas in the fourth to seventh embodiments, the temperature increases. It can also be seen that the minimum transmittance T _min hardly deteriorates, that is, the deterioration of the scattering at high temperatures is suppressed.

The charge holding characteristics of each liquid crystal optical element S were measured as shown in FIG.

The charge retention characteristics are evaluated using the degree of voltage retention when an AC electric field having a pulse width of 60 μs, an amplitude of ± 5 V and a frequency of 60 Hz is applied to the liquid crystal optical element S as an index.
In FIG. 6, reference numeral 60 denotes an applied waveform, and 61 denotes a waveform showing a state of a voltage drop of the liquid crystal optical element S. Further, an area A in which the pulse application interval of the applied waveform 60 is t and the waveform height of the applied waveform 60 is h, and an area B of the area A divided by the voltage drop waveform 61 of the liquid crystal optical element S are shown. Assuming that the value calculated from the ratio is the charge holding ratio, the charge holding ratio V _K is calculated by the following equation.

V _K (%) = B / A × 100 The better the charge retention, the smaller the voltage drop, and therefore the larger the area B and the higher the charge retention.

Table 2 below shows the values of the charge holding ratio V _k (%) at a temperature of 60 ° C. of the liquid crystal optical elements produced by the manufacturing methods of the embodiments and the comparative examples.

[0112]

[Table 2]

As is apparent from this table, the first to third embodiments are superior to the comparative examples 1 and 2 in the charge retention V _K. Furthermore, the fourth to seventh embodiments using a liquid crystal material further added with an ultraviolet absorber are superior in charge retention V _K as compared with Comparative Examples 3 to 7, and furthermore, the ultraviolet absorber is used. It can be seen that the charge retention ratio V _K is superior to those of the first to third embodiments in which no additive is added.

Further, the phase transition temperature T of each liquid crystal optical element S
_The results of measuring _ni (the temperature at which the phase shifts from the isotropic phase to the nematic phase) are shown in Table 3 below.

[0115]

[Table 3]

As is apparent from this table, the first to third embodiments have a higher phase transition temperature T _ni than Comparative Examples 1 and 2. Also, it can be seen that the fourth to seventh embodiments using the liquid crystal material further added with the ultraviolet absorber have a higher phase transition temperature T _ni than the comparative examples 3 to 7.

In Comparative Example 7, the minimum transmittance T
The change with time of _min and the phase transition temperature T _ni are extremely deteriorated. This is because the added ultraviolet absorber (5-chloro-2-hydroxybenzophenone) dissolves into the polymer-forming material and causes polymerization inhibition. It is considered that it is.

In the above-described embodiment, the dissolution parameter is a value calculated from the aggregation energy constant, the molecular weight and the density.
The solubility parameter may be determined from a value determined from the reciprocal density) and the heat of evaporation, or from the surface tension and the molecular volume.

Further, the weight ratio of the liquid crystal material and the liquid crystal in the polymer-dispersed liquid crystal and the mixing amount of the polymerization initiator and the ultraviolet absorber are not limited to those described in each embodiment. Furthermore, in each embodiment, one kind of oligomer material and one kind of monomer material are used. However, several kinds of materials may be mixed and used, and the optical annealing is performed while the polymer dispersed liquid crystal is heated. May be applied.

[0120]

As described above, according to the present invention,
The charge retention characteristics and the high-temperature scattering characteristics of a liquid crystal optical element using a polymer dispersed liquid crystal can be greatly improved. Hereinafter, the effects of each claim will be described.

Effects of Claims 1 and 9 After irradiating a liquid crystal material with a first light beam in the light absorption wavelength region of the first polymerization initiator, the light beam is subsequently applied to the light absorption wavelength region of the second polymerization initiator. By irradiating a certain second light beam, it becomes possible to cause a low molecular weight component such as a monomer material to penetrate into the liquid crystal material main body and then polymerize the low molecular weight component. As a result, the amount of the residue (low molecular weight component) in the liquid crystal material body can be reduced, and the liquid crystal optical element using this liquid crystal material or the liquid crystal optical element manufactured by the manufacturing method has improved charge retention characteristics and high-temperature scattering characteristics. Can be greatly improved.

Effects of Claims 2 and 10 A light ray in a wavelength range that is within the light absorption wavelength range of the first polymerization initiator and does not overlap with the light absorption wavelength range of the liquid crystal material body is used as the first light beam. By irradiating the liquid crystal material, the first light beam hardly adversely affects the liquid crystal material main body. Therefore, it is possible to further improve the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element manufactured using this liquid crystal material or manufactured by the manufacturing method.

Effects of Claims 3 and 11 Light rays in a wavelength range that is within the light absorption wavelength range of the first polymerization initiator and that does not overlap with the light absorption wavelength range of the second polymerization initiator are emitted from the first polymerization initiator. By irradiating the liquid crystal material with such a light beam, the first light beam hardly adversely affects the second polymerization initiator. Therefore, it is possible to further improve the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element manufactured using this liquid crystal material or manufactured by the manufacturing method.

[0124] Advantages of Claims 4 and 12: The light in the wavelength range that is within the light absorption wavelength range of the second polymerization initiator and does not overlap with the light absorption wavelength range of the liquid crystal material body is converted into the second light beam. By irradiating the liquid crystal material as, the second light beam hardly adversely affects the liquid crystal material main body. Therefore, it is possible to further improve the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element manufactured using this liquid crystal material or manufactured by the manufacturing method.

Effects of Claims 5 and 13 As the second light beam, a wavelength range that is within the light absorption wavelength range of the second polymerization initiator and does not overlap with the light absorption wavelength range of the first polymerization initiator. By irradiating the second light beam, the second
Hardly affects the first polymerization initiator optically. Therefore, the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element using this liquid crystal material or manufactured by this manufacturing method can be further improved.

The light absorber absorbs the first light beam into the liquid crystal material body and the second polymerization initiator, and the second light beam absorbs the second light beam into the liquid crystal material body. Control that. Therefore, it is possible to further improve the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element using this liquid crystal material or manufactured by this manufacturing method.

Effects of Claims 7 and 9 The light-absorbing agent effectively suppresses the absorption of the first light by the second polymerization initiator and the liquid crystal material body. Therefore, it is possible to further improve the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element using this liquid crystal material or manufactured by this manufacturing method.

Eighth and sixteenth effects The second light beam is not unnecessarily absorbed by the light absorber. Therefore, it is possible to further improve the charge retention characteristics and the high-temperature scattering characteristics of the liquid crystal optical element using this liquid crystal material or manufactured by this manufacturing method.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a liquid crystal optical element manufactured using the liquid crystal material of the present invention.

FIG. 2 is a perspective view showing a state in which a liquid crystal optical element manufactured using the liquid crystal material of the present invention is being manufactured.

FIG. 3 is a diagram showing absorption spectra of a liquid crystal material body, a first polymerization initiator, a second polymerization initiator, and a second polymerization initiator of the present invention.

FIG. 4 is a diagram showing absorption spectra of a liquid crystal material body, a first polymerization initiator, a second polymerization initiator, a second polymerization initiator, and an ultraviolet absorber according to the present invention.

FIG. 5 is a schematic view showing a method for evaluating the scattering characteristics of a liquid crystal crystal optical element.

FIG. 6 is a schematic diagram showing a method for evaluating the charge retention characteristics of a liquid crystal optical element.

[Explanation of symbols]

20 ₁ , 20 ₂ Liquid crystal material main body 21 Polymer forming material 22 ₁ First polymerization initiator 23 _1-6 Second polymerization initiator 24 _1-7 Liquid crystal material 25 ₁ , 25 ₂ UV absorber A, A ′ Liquid crystal Light absorption spectrum of material main body B, B 'Light absorption spectrum of first polymerization initiator C, C' Light absorption spectrum of second polymerization initiator A _W , C _W 'Light absorption wavelength range of liquid crystal material main body B _W , B _W ′ Light absorption wavelength region of the first polymerization initiator C _W , C _W ′ Light absorption wavelength region of the second polymerization initiator B _WL , B _WL ′ Light absorption wavelength region B _W Long wavelength region C _WL, the light absorption of the C _WL 'light absorption wavelength region C _W long wavelength side wavelength region D _W of, D _W' second polymerization initiator is almost non-resorbable wavelength region E _W, E _W 'UV absorber Wavelength range E _WT Maximum absorption wavelength range of UV absorber

Claims (16)

[Claims] 1. A liquid crystal material body, a polymer-forming material, a first polymerization initiator having poor compatibility with the liquid crystal material body,
A liquid crystal material comprising: a second polymerization initiator having good compatibility with a liquid crystal material main body. 2. The liquid crystal material according to claim 1, wherein:
Wherein the polymerization initiator has a wavelength range within the light absorption wavelength range that does not overlap with the light absorption wavelength range of the liquid crystal material body. 3. The liquid crystal material according to claim 1, wherein the first polymerization initiator has a light absorption wavelength range of:
A liquid crystal material having a wavelength range that does not overlap with the light absorption wavelength range of the second polymerization initiator. 4. The liquid crystal material according to claim 1, wherein the second polymerization initiator does not overlap with the light absorption wavelength region of the liquid crystal material body in its light absorption wavelength region. A liquid crystal material having a wavelength range. 5. The liquid crystal material according to claim 1, wherein the second polymerization initiator has a light absorption wavelength region of the first polymerization initiator within a light absorption wavelength region thereof. Is a liquid crystal material having a wavelength range that does not overlap. 6. The liquid crystal material according to claim 1, further comprising a light absorbing agent having good compatibility with a liquid crystal material body. 7. The liquid crystal material according to claim 6, wherein the light absorbing agent has a wavelength range overlapping with the light absorbing wavelength range of the first polymerization initiator in the light absorbing wavelength range. Liquid crystal material characterized by the following. 8. The liquid crystal material according to claim 6, wherein the second polymerization initiator has a light absorption wavelength range within the light absorption wavelength range.
A liquid crystal material having a wavelength range that does not overlap with the light absorption wavelength range of the light absorber. 9. A liquid crystal material main body, a polymer-forming material, a first polymerization initiator having poor compatibility with the liquid crystal material main body,
Arranging a liquid crystal material containing a second polymerization initiator having good compatibility with the liquid crystal material body in an arbitrary enclosed space; and light absorption of the first polymerization initiator in the liquid crystal material. Irradiating a first light beam in the wavelength region and then irradiating a second light beam in the light absorption wavelength region of the second polymerization initiator. Method. 10. The method for manufacturing a liquid crystal optical element according to claim 9, wherein the first polymerization initiator has a wavelength in its light absorption wavelength region that does not overlap with the light absorption wavelength region of the liquid crystal material body. Irradiating a light beam having a wavelength within the light absorption wavelength region of the first polymerization initiator and not overlapping with the light absorption wavelength region of the liquid crystal material body as the first light beam. A method for producing a liquid crystal optical element, comprising: 11. The method for producing a liquid crystal optical element according to claim 9, wherein the first polymerization initiator has a light absorption wavelength range of a second polymerization initiator within a light absorption wavelength range thereof. The first light ray is within the light absorption wavelength region of the first polymerization initiator and does not overlap with the light absorption wavelength region of the second polymerization initiator. A method for producing a liquid crystal optical element, which comprises irradiating light in a wavelength range. 12. The method of manufacturing a liquid crystal optical element according to claim 9, wherein the second polymerization initiator has a light absorption wavelength range of a liquid crystal material main body in its light absorption wavelength range. And a wavelength range that does not overlap with the light absorption wavelength range of the liquid crystal material body, as the second light ray, within the light absorption wavelength range of the second polymerization initiator. A method for manufacturing a liquid crystal optical element, comprising irradiating a light beam. 13. The method for manufacturing a liquid crystal optical element according to claim 9, wherein the light of the first polymerization initiator is included in the light absorption wavelength region as the second polymerization initiator. The light having a wavelength range that does not overlap with the absorption wavelength region is used, and the second light beam is within the light absorption wavelength region of the second polymerization initiator, and the light absorption wavelength region of the first polymerization initiator. Is a method for manufacturing a liquid crystal optical element, which comprises irradiating light beams in wavelength ranges that do not overlap. 14. The method for manufacturing a liquid crystal optical element according to claim 9, wherein a liquid crystal material further containing a light absorber compatible with a liquid crystal material body is used. A method for manufacturing a liquid crystal optical element, comprising: 15. The method for manufacturing a liquid crystal optical element according to claim 14, wherein the light absorbing agent has a light absorption wavelength region overlapping with the light absorption wavelength region of the first polymerization initiator. And irradiating, as the first light beam, a light beam having a wavelength within the light absorption wavelength region of the light absorber and overlapping with the light absorption wavelength region of the first polymerization initiator. Of manufacturing a liquid crystal optical element. 16. The method for manufacturing a liquid crystal optical element according to claim 14, wherein the light absorption wavelength region of the second polymerization initiator overlaps with the light absorption wavelength region of the second polymerization initiator. A light having a wavelength range not to be used is irradiated as a second light ray with a wavelength range that is the light absorption wavelength range of the second polymerization initiator and does not overlap with the light absorption wavelength range of the light absorption agent. A method for manufacturing a liquid crystal optical element, comprising: