JP2008310188A - Liquid crystal optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal optical element excellent in design property. <P>SOLUTION: This liquid crystal optical element is provided with the first and second transparent substrates 11, 21, electrodes 12, 22 formed on respective inner faces of the first and second transparent substrates, a sealing frame 30 formed between an outer circumferential edge on an inner face of the second transparent substrate and an inner face of the first transparent substrate, and for joining the inner faces of the first and second transparent substrates, and a composite 12 of a liquid crystal and a cured product filled in a space surrounded with the first and second transparent substrates and the sealing frame. Visible ray transmittances of the composite and the sealing frame are 70% or more both in an unimpressed state with voltage to the composite. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal optical element.

  Since the liquid crystal optical element has advantages such as low power consumption, thinness, and light weight, it is widely used in many electronic devices such as mobile phones, digital cameras, personal digital assistants, and televisions. Among them, in recent years, a liquid crystal optical element of a display system that changes the light scattering state by controlling the arrangement of liquid crystal molecules by an electric field has been proposed.

  Patent Document 1 discloses a liquid crystal optical element (hereinafter, referred to as a liquid crystal / cured material composite element) provided with a composite of liquid crystal and a cured product. Specifically, the photocurable compound in the mixture of the liquid crystal and the uncured curable compound is exposed and photocured to increase the difference in transmittance between the transmission state and the scattering state, thereby improving the contrast. . Since this liquid crystal / cured material composite element does not require a polarizing plate in principle, it has a high light transmittance. Further, when a non-voltage is applied, the liquid crystal is aligned perpendicularly to the substrate and becomes transparent, and when a voltage is applied, the liquid crystal is randomly aligned and becomes a scattering state. For this reason, the use for the show window which can display a character and a pattern, various bulletin boards, the instrument panel of a motor vehicle, etc. is proposed.

Here, in a general liquid crystal optical element, a liquid crystal is filled in a space between a pair of transparent substrates and surrounded by a seal frame. This seal frame is provided for the purpose of preventing leakage of the liquid crystal, preventing the penetration of moisture into the liquid crystal, preventing the corners of the liquid crystal optical element from being chipped, and maintaining the adhesion between the pair of substrates. The seal frame usually has a color such as white or gray. Conventionally, in a general liquid crystal optical element, this seal frame is hidden by, for example, an outer case and cannot be seen from the outside.
JP 2000-119656 A

  Since the liquid crystal / cured material composite element is used for a show window or the like as described above, a product having a large size, specifically, a product exceeding 1 m × 1 m is also required. In such a large-sized liquid crystal optical element, for example, when only a partial region of the show window needs to be displayed in a liquid crystal display, the outer peripheral edge of the liquid crystal display region is often exposed. For this reason, when an observer looks at the display information of the liquid crystal optical element, a colored sticker frame is also seen, and the appearance is poor and the design is poor.

  The present invention has been made in view of such problems, and an object thereof is to provide a liquid crystal optical element excellent in design.

The liquid crystal optical element according to aspect 1 of the present invention is:
First and second transparent substrates;
An electrode formed on each inner surface of the first and second transparent substrates;
A seal frame formed between the outer peripheral edge of the inner surface of the second transparent substrate and the inner surface of the first transparent substrate, and joining the inner surfaces of the first and second transparent substrates;
A liquid crystal optical element comprising a composite of a liquid crystal and a cured product, filled in a space surrounded by the first and second transparent substrates and the seal frame,
The visible light transmittance of the composite and the seal frame in a state where no voltage is applied to the composite is 70% or more.
As a result, in a state where no voltage is applied to the liquid crystal optical element, the entire liquid crystal optical element is transparent until it reaches every corner, and a liquid crystal optical element excellent in design can be provided.

  The liquid crystal optical element according to aspect 2 of the present invention is characterized in that, in the above aspect of the invention, the difference between the haze value of the seal frame and the haze value at the time of transmission of the composite is ± 3% or less. Is. Thereby, the liquid crystal optical element excellent in the designability can be provided reliably.

  The liquid crystal optical element according to aspect 3 of the present invention is characterized in that, in the above aspect of the invention, the seal frame is made of a polyene-polythiol polymer. Thereby, inhibition of polymerization by oxygen can be prevented.

  The liquid crystal optical element according to aspect 4 of the present invention is characterized in that, in the above aspect of the invention, the polyene-polythiol polymer is photocurable. Thereby, the productivity of the liquid crystal optical element can be improved.

  The liquid crystal optical element according to aspect 5 of the present invention is characterized in that, in the above aspect of the invention, the cured product is a photocurable resin. Thereby, the display performance and productivity of the liquid crystal optical element can be improved.

  According to the present invention, a liquid crystal optical element excellent in design can be provided.

Embodiment.
Embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

  1A is a plan view of a liquid crystal optical element 1 according to an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along the line XX of FIG. 1A, and FIG. It is sectional drawing to which the inside of the dotted-line circle of 1 (b) was expanded. As shown in FIG. 1, a liquid crystal optical element 1 according to an embodiment of the present invention includes a first transparent substrate 11, a first transparent electrode 12, a second transparent substrate 21, a second transparent electrode 22, and a seal. A material 30, a spacer 40, and a composite layer 50 are provided.

  Specifically, in the liquid crystal optical element 1, the first transparent substrate 11 and the second transparent substrate 21 are opposed to each other, and the liquid crystal optical element 1 / the liquid crystal optical element 1 is different between the first and second transparent substrates 11 and 21 having different sizes. The composite layer 50 of hardened | cured material is clamped and comprised. That is, the composite layer 50 is formed only in the portions that require functions such as decoration by liquid crystal display and character display.

  The first and second transparent substrates 11 and 21 are insulating substrates. For example, a glass substrate, a resin substrate made of polycarbonate, acrylic resin, or a resin film substrate is used. In this embodiment, the first transparent substrate 11 has a larger area than the second transparent substrate 21. A plurality of second transparent substrates 21 may be provided for one large first transparent substrate 11. Of course, the area and shape of the first and second transparent substrates 11 and 21 may be the same.

  On the inner surface of the first transparent substrate 11, a plurality of first transparent electrodes 12 are formed in a stripe shape. On the other hand, a plurality of second transparent electrodes 22 are formed in stripes on the inner surface of the second transparent substrate 21. Note that. The plurality of second transparent electrodes 22 are formed so as to intersect with the plurality of first transparent electrodes 12 substantially orthogonally. The first and second transparent electrodes 12 and 22 are made of, for example, ITO (Indium Tin Oxide). One of the first and second transparent electrodes 12 and 22 may be a reflective electrode made of Al or a dielectric multilayer film. Of course, the shape of the electrode is not limited to the orthogonal stripe shape, and a specific mark or character may be displayed.

  An alignment film (not shown) is formed on the first and second transparent electrodes 12 and 22 formed on the first and second transparent substrates 11 and 21, respectively. The alignment film is formed in contact with the liquid crystal in order to align the liquid crystal in the composite layer 50 in a predetermined direction. Here, at least one of the alignment films formed on each of the transparent substrates 11 and 21 increases the transmittance in the transmissive state by orienting the liquid crystal vertically to the inner surfaces of the transparent substrates 11 and 21. You can also. Further, an insulating thin film such as a metal oxide may be further formed between the transparent electrode and the alignment film for the purpose of improving the electrical insulation of the element.

  The sealing material 30 is formed in a frame shape along the periphery of the second transparent substrate 21 between the first and second transparent substrates 11 and 21. The first and second transparent substrates 11 and 21 are joined by a sealing material 30. In the liquid crystal optical element according to the present embodiment, the sealing material 30 is not hidden by a case or the like and is visible from the outside. Conventional sealing materials are tinged with color, have a poor appearance and are poor in design. On the other hand, the sealing material 30 according to the present invention has transparency. Specifically, since the visible light transmittance of the sealing material 30 is 70% or more, the sealing material 30 does not noticeably deteriorate the appearance, and a liquid crystal optical element excellent in design can be provided. .

  Here, the difference between the haze value of the sealing material 30 and the haze value at the time of transmission through the composite layer 50 is preferably ± 3% or less. When the absolute value of the difference between the haze value of the sealing material 30 and the haze value at the time of transmission through the composite layer 50 is large, the sealing material 30 becomes conspicuous.

  As a material of the sealing material 30, for example, a polyene-polythiol-based ultraviolet curable resin (hereinafter referred to as UV resin) or a thermosetting resin is preferable. Since the sealing material 30 has a portion exposed to the outside, polymerization inhibition due to oxygen becomes a problem, but the polyene-polythiol-based curable compound does not cause polymerization inhibition due to oxygen. Furthermore, if both the sealing material 30 and the cured product constituting the composite layer 50 are made of UV resin, both can be cured simultaneously in the production process, which is preferable from the viewpoint of improving productivity. In addition, as another curable compound having transparency, an acrylic type or an epoxy type can be considered. However, the acrylic type is not preferable because the polymerization is inhibited by the oxygen. Moreover, about the epoxy type, since the hardened | cured material which comprises the composite layer 50 is an epoxy type, in the manufacturing process, the sealing material 30 before hardening and the liquid crystal composition before hardening (mixture of a liquid crystal and a curable compound) and May be mixed, which is not preferable.

  Further, in order to draw out the second transparent electrode 22 formed on the second transparent substrate 21 to the outside, the sealant 30 is close to a spacer 40 described later in order to provide conductivity having anisotropy. Conductive particles of size are dispersed. Thereby, the 2nd transparent electrode 22 is pulled out outside through the sealing material 30 and the 1st transparent electrode 12, without impairing the designability.

  The spacers 40 are uniformly distributed in a space surrounded by the first and second transparent substrates 11 and 21 and the sealing material 30. The spacer 40 controls the cell gap. The cell gap, that is, the diameter of the spacer 40 is preferably 2 to 50 μm, and more preferably 4 to 30 μm. When the cell gap is too small, the contrast is lowered, and when it is too large, the driving voltage is increased. The spacer 40 is made of a hard material such as glass particles, silica particles, or cross-linked acrylic particles. It is also possible to form a rib-like spacer on one substrate instead of being spherical.

  The composite layer 50 is enclosed in a space surrounded by the first and second transparent substrates 11 and 21 and the sealing material 30. The composite layer 50 is made of a mixture of a liquid crystal and a cured product. Specific constituent materials will be described in detail later. Since the liquid crystal is vertically aligned and has a domain structure, it scatters when a voltage is applied. Therefore, it is called a scattering display unit. The scattering display portion is in a transparent state when no voltage is applied, and the transmittance changes when a voltage is applied, resulting in a scattering state. Therefore, the scattering display unit becomes an operation region where the liquid crystal operates by voltage.

  As the liquid crystal, nematic liquid crystal which is an electric field driving type material is used. Two or more kinds of liquid crystals may be used in combination. In addition, in the case of aiming at display by an electric field, it is preferable to use one having a negative dielectric anisotropy because the transmittance in the transmissive state can be increased by making the alignment direction of the liquid crystal vertical. . However, the polarity of dielectric anisotropy may be positive or negative. In order to reduce the driving voltage, it is preferable that the dielectric anisotropy is large.

The photocurable resin suitable for the embodiment of the present invention will be described. The composite layer 50 used in the liquid crystal optical element according to the embodiment of the present invention has a visible light transmittance of 70% or more. The composite layer 50 includes at least one or more of the bifunctional polymerizable compound (A) represented by the following chemical formula (1) and one or more of the bifunctional polymerizable compound (B) represented by the chemical formula (2). And non-polymerizable liquid crystal.

  The bifunctional polymerizable compound (A) forms a main skeleton component having rigidity in the resin. On the other hand, the bifunctional polymerizable compound (B) forms a flexible component that can play a role of shock absorption in the resin. By combining such compounds having different physical properties, a liquid crystal / cured material composite layer 50 suitable for the liquid crystal optical element 1 can be obtained. Of course, resin which forms hardened | cured material is not limited to this.

  The bifunctional polymerizable compound (A) will be described. The bifunctional polymerizable compound (A) is not particularly limited as long as it is a compound satisfying the chemical formula (1).

Moreover, it is preferable that the bifunctional polymerizable compound (A) represented by the chemical formula (1) is a compound that satisfies the following conditions.
A ₁ and A ₂ are each independently an acryloyloxy group, a methacryloyloxy group, or a vinyl ether group.
Q ₁ , Q ₂ , Q ₃ and Q ₄ are each independently a 1,4-phenylene group or a 1,4-cyclohexylene group which may have a substituent.

X ₁ and X ₂ are each independently a single bond, an oxygen atom or an ester bond.
R ₁ and R ₂ are each independently a single bond or a linear or branched alkylene group having 2 to 20 carbon atoms which may have one or more etheric oxygen atoms between carbon atoms. .
Z _{1, Z} 2, _{Z 3} are each independently a single bond, -C (= O) -O - , - O-C (= O) -, - CH 2 -CH 2 -, - C≡C- , —CH ₂ —O—, —O—CH ₂ —.
p and q are both 0 or one is 0 and the other is 1.

Moreover, it is preferable that the bifunctional polymerizable compound (A) represented by the chemical formula (1) is a compound that satisfies the following conditions.
A ₁ and A ₂ are each independently an acryloyloxy group or a methacryloyloxy group.
Q ₁ and Q ₂ are both 1,4-phenylene groups which may have a substituent, and Q ₃ and Q ₄ may each independently have a substituent. A phenylene group or a 1,4-cyclohexylene group.

Z _{1, Z} 2, _{Z 3} are each independently a single bond, -C (= O) -O - , - O-C (= O) -, - CH 2 -CH 2 - or -C≡C- It is.
p and q are both 0 or one is 0 and the other is 1.
Moreover, it is preferable that the bifunctional polymerizable compound (A) represented by the chemical formula (1) is a compound that satisfies the following conditions.
A ₁ and A ₂ are both acryloyloxy groups.

Q ₁ and Q ₂ are both 1,4-phenylene groups which may have a substituent, and Q ₃ and Q ₄ may each independently have a substituent. A phenylene group or a 1,4-cyclohexylene group.
R ₁ and R ₂ are each independently a linear or branched alkylene group having 2 to 20 carbon atoms.
Z ₁ is a single bond, -C (= O) -O - , - O-C (= O) -, - CH 2 -CH 2 - or a _-C≡C-, one is Z 2, _{Z 3} Is also a single bond.
p and q are both 0 or one is 0 and the other is 1.

As a specific example of the bifunctional polymerizable compound (A) for forming the liquid crystal / cured material composite layer 50 used in the liquid crystal optical element 1 of the present invention, a compound represented by the following chemical formula (3) is exemplified. Can do.

  The bifunctional polymerizable compound (A) is classified into a compound having liquid crystallinity and a compound having no liquid crystallinity based on its properties. A bifunctional polymerizable compound (A) having liquid crystallinity can be used as one component of the mixture. That is, in addition to the case where only the bifunctional polymerizable compound (A) having no liquid crystallinity is used, the bifunctional polymerizable compound (A) having no liquid crystallinity and the bifunctional polymerizable compound (A) having liquid crystallinity are combined. The bifunctional polymerizable compound (A) having liquid crystallinity can be used alone.

Next, the bifunctional polymerizable compound (B) will be described. The bifunctional polymerizable compound (B) is not particularly limited as long as it satisfies the chemical formula (2). For example, it is a compound that satisfies the following conditions.
A ₃ and A ₄ are each independently an acryloyloxy group, a methacryloyloxy group, or a vinyl ether group.
R ₃ is —R ₄ — or — (R ₅ —O) _n —R ₅ —.

However, R ₄ is a linear or branched alkylene group having 2 to 20 carbon atoms, R ₅ is a linear or branched alkylene group having 2 to 8 carbon atoms, n represents 1-10 integer is there.
Alternatively, R ₄ is a linear alkylene group having 2 to 20 carbon atoms, and R ₅ is — (CH ₂ ) r—, —CH ₂ —CH (CH ₃ ) —, —CH ₂ —CH ₂ —CH (CH ₃ )-or —CH ₂ —CH ₂ —C (CH ₃ ) ₂ — (wherein r is an integer of 2 to 5), and n is an integer of 1 to 6.

A bifunctional polymerizable compound (B) may be used independently and may be used in combination of 2 or more types. A specific example is shown in the following chemical formula (4).

The bifunctional polymerizable compound (B) has polymerizable groups A ₃ and A ₄ and R ₃ that connects the polymerizable groups. As R ₃ , a group having a single bond between atoms and having a high degree of freedom of intramolecular rotation is selected. By comprising in this way, the softness | flexibility of the polymerized polymer can be improved. Also, the reactivity of the polymerization phase separation can be increased.

Flexibility improves as the number of carbon atoms between A ₃ and A ₄ and the number of etheric oxygen atoms increase. On the other hand, the compatibility with the liquid crystal decreases as the number of atoms increases. Therefore, the number of atoms is selected appropriately. In the case of adopting the ODF method, the volatility is taken into consideration, and the number of carbon atoms is 8 or more, preferably 11 or more. An etheric oxygen atom may or may not be included. When it contains an etheric oxygen atom, the flexibility of the polymer is improved, which is preferable.

Since the compound of the chemical formula (B) does not contain a group such as Q _{1 in} the molecule, it is relatively easy to increase the number of carbon atoms contained in R ₃ . By adopting this structure, the flexibility of the polymer is greatly improved.
In order to polymerize the polymerizable monomer, it is preferable to use a polymerization initiator. Such a polymerization initiator can be appropriately selected from known polymerization catalysts. For example, when the photopolymerization phase separation method is used, a general photopolymerization initiator such as benzoin ether, acetophenone, or phosphine oxide can be used.

  Furthermore, various compounds can be added for the purpose of improving the contrast ratio and stability. For example, for the purpose of improving contrast, various dichroic dyes such as anthraquinone, styryl, azomethine, and azo can be used. In that case, it is preferable that the dichroic dye is basically compatible with the liquid crystal compound and incompatible with the curable compound. In addition to these, addition of an antioxidant, an ultraviolet absorber, and various plasticizers is also preferable from the viewpoint of improving stability and durability.

  Next, the operation of the liquid crystal optical element 1 described above will be described. When a voltage is applied between the first and second transparent electrodes 12 and 22, the liquid crystal is randomly oriented by the electric field between the electrodes, and the composite layer 50 enters a scattering state. On the other hand, when no voltage is applied between the first and second transparent electrodes 12 and 22, the liquid crystal is aligned, so that the composite layer 50 is in a transparent state. The composite layer 50 in the transparent state can observe the back surface (anti-observation surface) of the liquid crystal optical element 1. As described above, since the scattering state and the transparent state are changed by applying and not applying a voltage, a desired image or the like can be displayed.

  A liquid crystal optical element that is in a transmission state when a voltage is applied and in a scattering state when no voltage is applied may be used. However, in a vehicle application or the like, a liquid crystal optical element that is in a scattering state when a voltage is applied and in a transmission state when no voltage is applied is preferable from the viewpoint of fail-safe.

  Next, a method for manufacturing the liquid crystal optical element 1 will be described. FIG. 2 is a diagram showing an example of a manufacturing flow of the liquid crystal optical element according to the embodiment of the present invention. As shown in FIG. 2, this manufacturing flow consists of 8 steps from ST201 to ST208.

  First, a transparent electrode film for forming the first and second transparent electrodes 12 and 22 is formed on the inner surfaces of the first and second transparent substrates 11 and 21 by a sputtering method, a vacuum evaporation method, or the like (ST201). ). As the transparent electrode film, ITO is suitable as described above. The transparent electrode film is patterned by, for example, photolithography to form the first and second transparent electrodes 12 and 22.

  Next, an alignment film (not shown) is formed on the surface on which the transparent electrodes of the first and second transparent substrates 11 and 21 are formed (ST202). The alignment film is formed in contact with the liquid crystal in order to align the liquid crystal in the composite layer 50 in a predetermined direction. As described above, at least one of the alignment films formed on the transparent substrates 11 and 21 is formed so that the liquid crystal is aligned perpendicularly to the inner surfaces of the transparent substrates 11 and 21. The alignment film on the transparent substrate 11 may be formed only in a region facing the transparent substrate 21.

  Next, the spacer 40 is spread | dispersed on the inner surface of the 1st or 2nd transparent substrate 11 and 21 using a spreader (ST203).

  Next, the sealing material 30 is applied along the periphery of the second transparent substrate 21 on the inner surface of the second transparent substrate 21 (ST204). Note that the sealing material 30 may be applied on the inner surface of the first transparent substrate 11 at a position where the second transparent substrate 21 is bonded. Moreover, you may divide | segment and apply | coat to both the 1st and 2nd transparent substrates 11 and 21. FIG.

  Next, a liquid crystal composition made of a mixture of nematic liquid crystal and an uncured photocurable compound is dropped onto the inner surface of the first or second transparent substrate 11 or 21 using the ODF method (ST205). This ODF method can arrange a liquid crystal composition between the transparent substrates 11 and 21 easily and in a short time compared with the above-mentioned suction method. This ODF method is particularly effective for manufacturing a large-sized liquid crystal optical element. However, a suction method or other methods may be used. The ODF method is also called a liquid crystal dropping method, a vacuum dropping method, or the like.

  Next, the first and second transparent substrates 11 and 21 are bonded together with the sealing material 30 under reduced pressure (ST206). Specifically, after aligning the first and second transparent substrates 11 and 21 using an alignment mark or the like, the first and second transparent substrates 11 and 21 are bonded together by the adhesive 30. Moreover, the atmospheric pressure of 20 Pa or less is preferable, and it can be said that it is generally in a vacuum.

  Next, the bonded transparent substrates 11 and 21 are taken out from the reduced pressure to the atmospheric pressure (ST207). Due to the pressure difference between the inside and outside of the cell, the two transparent substrates are drawn to the cell gap maintained by the spacer, and the mixture is filled in the cell.

  Next, the uncured photocurable compound in the sealing material 30 and the liquid crystal composition is exposed and cured by an ultraviolet light source or the like (ST208). By exposure, the photocurable compound is cured, and a composite layer 50 of liquid crystal / cured product is formed. In addition, when the sealing material 30 is not a photocurable hardened | cured material, it is necessary to perform hardening of a sealing material separately.

  Below, the Example concerning this invention is shown. The visible light transmittance was measured using SPECTRO MULTI CHANNELEL PHOTO DETECTOR (MCPD-10000) manufactured by Otsuka Electronics. The haze value was measured using a direct reading haze computer HGM-2 manufactured by Suga Test Instruments Co., Ltd.

[Adjustment of liquid crystal composition]
To the nematic liquid crystal (Tc = 98 ° C., Δn = 0.220, Δε = −5.6) exhibiting negative dielectric anisotropy, the photocurable compound 3 was added so as to be 20% of the total amount. The solution was dissolved by heating and stirring on a hot stirrer at 100 ° C. Furthermore, a liquid crystal composition (liquid crystal composition A) was obtained by adding about 1 mass% of a photopolymerization initiator (benzoin isopropyl ether) to the photocurable compound contained in the liquid crystal composition.

[Adjustment of sealant A]
About 2.1 equivalent of triallyl isocyanurate (Mw: 250) was added to tris-2-hydroxyethylisocyanurate-tris-3-mercaptopropionate (Mw: 526), and further 1 wt% of the monomer weight. A photopolymerization initiator (benzoin isopropyl ether) was added. After stirring these well, 0.3 wt% glass spacer (Gap diameter: 6 μm) was added to the total weight, and the mixture was further stirred to uniformly disperse the glass spacer. This was designated as sealant A.

[Example 1]
On the ITO electrode of a pair of glass substrates provided with an ITO thin film (indium tin oxide) on the inner surface as a transparent electrode, a SiO ₂ —TiO ₂ based metal oxide thin film (Seimi Chemical Co., Ltd .: MIC-55) as an insulating layer Is formed to a thickness of about 50 nm. Further, an alignment film made of a polyimide thin film having a pretilt angle of 90 ° is formed thereon. Spacers made of resin beads having a diameter of 6 μm are uniformly dispersed on the glass substrate, and a sealing agent A is applied to the four sides of the glass substrate. An amount of the liquid crystal composition A that fills the inner surface of the first or second transparent substrate 11, 21 is dropped.

Further, the first and second transparent substrates 11 and 21 are bonded together with the sealing material 30 under reduced pressure (ST206). Next, the bonded transparent substrates 11 and 21 are taken out from the reduced pressure to the atmospheric pressure (ST207). Due to the pressure difference between the inside and outside of the cell, the two transparent substrates are drawn to the cell gap maintained by the spacer, and the mixture is filled in the cell. Next, ultraviolet light having a central wavelength of 365 nm and an irradiation intensity of 30 W / m ² is irradiated from both sides of the cell for 10 minutes to cure the curable compound in the sealing material 30 and the liquid crystal material. (ST208). By exposure, the photocurable compound is cured, and a composite layer 50 of liquid crystal / cured product is formed.

  After irradiation with ultraviolet rays, both the seal part and the inside of the cell were in a uniform transparent state. The transmittance of the seal part was 85% and the haze value was 1% or less. Further, the transmittance inside the cell was 83.5% and the haze value was 2.7%.

  When the polyene-polythiol-based polymer according to the present invention is used as a sealant, it is possible to provide a seal site with high transparency and high designability unlike conventional sealants. In addition, inhibition of polymerization by oxygen can be prevented, and, as with the liquid crystal optical element, it is photocurable, so that productivity can be improved.

[Adjustment of sealant B]
World Rock: No.717 (epoxy resin compound manufactured by Kyoritsu Chemical Industry Co., Ltd.) was added with 0.3 wt% glass spacer (Gap diameter: 6 μm) and stirred to uniformly disperse the glass spacer. . This was designated as sealant B.

[Comparative Example 1]
A liquid crystal / cured product composite layer 50 was formed in the same manner as in [Example 1] except that the sealant B was used for the seal part.

  After irradiation with ultraviolet rays, the sealed portion exhibited a slight scattering state, while the inside of the cell exhibited a uniform transparent state. The transmittance of the sealed part was 42% and the haze value was 44%. Further, the transmittance inside the cell was 84.0% and the haze value was 2.4%.

[Adjustment of sealant C]
Strctbond: S-45 (manufactured by Mitsui Chemicals) was added with 0.3 wt% glass spacer (Gap diameter: 6 μm) and stirred to uniformly disperse the glass spacer. This was designated as sealant C.

[Comparative Example 2]
On the ITO electrode of a pair of glass substrates provided with an ITO thin film (indium tin oxide) on the inner surface as a transparent electrode, a SiO ₂ —TiO ₂ based metal oxide thin film (Seimi Chemical Co., Ltd .: MIC-55) as an insulating layer Is formed to a thickness of about 50 nm. Further, an alignment film made of a polyimide thin film having a pretilt angle of 90 ° is formed thereon. Spacers made of resin beads having a diameter of 6 μm are uniformly dispersed on the glass substrate to obtain the first or second transparent substrates 11 and 21. A sealing material C is applied along the periphery of the first or second transparent substrate 11 or 21 (ST205).

Here, the used sealing material C is a thermosetting resin or the like. Next, the first or second transparent substrates 11 and 21 are bonded together, and left in a 160 ° C. high temperature bath for 1 hour to perform thermosetting to obtain a cell. The cell is filled with liquid crystal composition A using a suction method (ST206). Next, at room temperature, the glass substrate surface is irradiated with ultraviolet rays having a central wavelength of 365 nm and an irradiation intensity of 30 W / m ² from both sides of the cell for 10 minutes to cure the curable compound, thereby combining the liquid crystal / cured product. A body layer 50 is formed.

  After the ultraviolet irradiation, the cured part was clouded, and the transmittance was 6% and the haze value was 80%. Further, the transmittance inside the cell was 83.3% and the haze value was 2.9%.

It is a figure which shows typically the structure of the liquid crystal optical element concerning embodiment of this invention. It is a figure which shows an example of the manufacturing flow of the liquid crystal optical element concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal optical element 2 Transparent substrate lamination apparatus 11 1st transparent substrate 21 2nd transparent substrate 12 1st transparent electrode 22 2nd transparent electrode 30 Seal material 40 Spacer 50 Composite layer

Claims (5)

First and second transparent substrates;
An electrode formed on each inner surface of the first and second transparent substrates;
A seal frame formed between the outer peripheral edge of the inner surface of the second transparent substrate and the inner surface of the first transparent substrate, and joining the inner surfaces of the first and second transparent substrates;
A liquid crystal optical element comprising a composite of a liquid crystal and a cured product filled in a space surrounded by the seal frame between the inner surfaces of the first and second transparent substrates,
Both the composite and the seal frame have a visible light transmittance of 70% or more when no voltage is applied to the composite.   2. The liquid crystal optical element according to claim 1, wherein a difference between a haze value of the seal frame and a haze value in a transmission state of the composite is ± 3% or less.   The liquid crystal optical element according to claim 1, wherein the seal frame is made of a polyene-polythiol polymer.   The liquid crystal optical element according to claim 3, wherein the polyene-polythiol polymer is photocurable.   The liquid crystal optical element according to claim 1, wherein the cured product is a photocurable resin.

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