WO2021033650A1 - Liquid crystal element and liquid crystal element manufacturing method - Google Patents

Abstract

A liquid crystal element manufacturing method according to the present disclosure includes regulating the alignment of the helical axis of a cholesteric liquid crystal by irradiating a mixture including a liquid crystal monomer, a chiral agent, and a photopolymerization initiator with light having a light intensity distribution.

Description

Liquid crystal element and manufacturing method of liquid crystal element

The present disclosure relates to a liquid crystal element and a method for manufacturing the liquid crystal element. This application claims priority based on Japanese Patent Application No. 2019-149514 filed on August 16, 2019, and incorporates all the contents described in the Japanese application.

Patent Document 1 discloses a liquid crystal lens including a lens layer. The lens layer of Patent Document 1 includes a cholesteric orientation region containing cholesterically oriented liquid crystal molecules.

Patent Document 2 discloses a liquid crystal film having a fixed cholesteric orientation. Further, Patent Document 2 discloses a fingerprint-like tissue formed by a cholesteric liquid crystal (in particular, see FIG. 1 of Patent Document 2).

International Publication No. 2013/119066 Japanese Unexamined Patent Publication No. 2006-154856

There is a mechanical orientation control method as a method for controlling the orientation structure of liquid crystal molecules. As a mechanical orientation control method, for example, there is a stretching method in which liquid crystal molecules are oriented so as to be parallel to the stretching direction by stretching the polymer film in one direction. However, in the mechanical orientation control method, one-dimensional orientation control is easy, but two-dimensional or three-dimensional orientation control is difficult.

There is also a photo-orientation method that can freely control the orientation of liquid crystal molecules by utilizing the interaction between polarization-selective dye molecules such as azobenzene and polarized light irradiation. However, the molecular orientation control that can be achieved by the photo-alignment method is limited to miniaturization from several tens of micrometers to several millimeters in principle, and in the creation of more advanced optical functional materials, the development of new molecular orientation technology Is desired.

The present inventors focused on the periodic structure of the liquid crystal that is spontaneously formed in order to precisely control the molecular orientation. Since the periodic structure of the liquid crystal is the size of nano-order, it is much finer than the structure size obtained by the conventional molecular orientation control technique. For example, cholesteric liquid crystals spontaneously form a periodic structure on the order of nm to μm in which liquid crystal molecules are spirally oriented. In addition, the smectic liquid crystal has a layered periodic structure.

Therefore, if the direction of the periodic structure of the liquid crystal is oriented in a desired two-dimensional direction or three-dimensional direction, a fine and desired two-dimensional or three-dimensional molecular orientation structure can be obtained. Here, the direction of the periodic structure means the direction in which the structure changes in the periodic structure. For example, in the case of cholesteric liquid crystal, the direction of the spiral axis is the direction of the periodic structure, and in the case of smectic liquid crystal, the direction of the layer thickness. Is the direction of the periodic structure.

One aspect of the present disclosure is a film-like liquid crystal element having a cholesteric liquid crystal. The disclosed liquid crystal element includes a first region in which the spiral axis of the cholesteric liquid crystal is oriented parallel to the in-plane direction of the film-shaped liquid crystal element and the orientation is restricted in the in-plane direction.

From another point of view, the disclosed liquid crystal element includes a first region having a cholesteric liquid crystal whose molecular orientation is regulated from each of a first surface and a second surface parallel to the direction orthogonal to the first surface.

Another aspect of the present disclosure is a method for manufacturing a film-shaped liquid crystal element using a cholesteric liquid crystal. In the disclosed production method, a mixture containing a liquid crystal monomer, a chiral agent, and a photopolymerization initiator is arranged in a film shape on a substrate that has been subjected to an orientation treatment, and a light intensity distribution is performed on a plane parallel to the substrate. By irradiating the film-like mixture with light having the above, a non-photopolymerized monomer region and a photopolymerized polymer region are formed.

In another aspect, the disclosed method for manufacturing a liquid crystal element is to irradiate a mixture containing a liquid crystal monomer, a chiral agent, and a photopolymerization initiator with light having a light intensity distribution to obtain a spiral axis of a cholesteric liquid crystal. Prepare to regulate orientation.

From another point of view, the disclosed method for producing a liquid crystal element is to photopolymerize in the mixture by the light intensity distribution of the irradiated light to the mixture containing a liquid crystal monomer and causing photopolymerization by irradiation with light. A concentration distribution of the polymer produced by the above is generated, and the periodic structure of the liquid crystal is oriented by utilizing the concentration distribution.

From another point of view, the disclosed method for manufacturing a liquid crystal element is isometric in the mixture depending on the light intensity distribution of the irradiated light to the mixture containing a liquid crystal monomer and photopolymerization occurs when the mixture is irradiated with light. It is provided to generate a distribution of the phase transition temperature from the phase to the liquid crystal phase and to orient the periodic structure of the liquid crystal by utilizing the distribution of the phase transition temperature.

From another viewpoint, the disclosed liquid crystal element is a liquid crystal element having a periodic structure, in which the periodic structure is oriented parallel to the in-plane direction of the liquid crystal element and the orientation is regulated in the in-plane direction. It has a first area.

Further details will be described as embodiments described below.

FIG. 1 is a flowchart showing a manufacturing process of an element using a cholesteric liquid crystal. FIG. 2 is a diagram showing a material composition. FIG. 3 is a perspective view showing an apparatus for manufacturing a liquid crystal element. FIG. 4 is a cross-sectional view showing a pattern exposure. FIG. 5 is an enlarged cross-sectional view showing a pattern exposure. FIG. 6 is a plan view showing the liquid crystal orientation structure in the monomer region. FIG. 7 is a plan view showing the liquid crystal orientation structure in the monomer region. FIG. 8 is a diagram showing a material composition for obtaining the orientation structure of FIG. 7. FIG. 9 shows a reference example and an example of the present disclosure regarding the molecular orientation regulating force. FIG. 10 is a cross-sectional view showing post-exposure. FIG. 11 is a diagram showing a measurement system for diffracted light. FIG. 12 is an imaging result of diffracted light. FIG. 13 is a plan view of the photomask. FIG. 14 is a plan view showing the monomer / polymer region obtained by the photomask of FIG. FIG. 15 is a diagram showing a material composition according to the second example. FIG. 16 is a diagram showing the composition and phase transition behavior of the monomer mixture. FIG. 17 is a perspective view showing an apparatus for manufacturing a liquid crystal element. FIG. 18 is a diagram showing a manufacturing process of the liquid crystal process. FIG. 19 is a polarizing micrograph (interference filter; λ = 550 nm) of the monomer mixture at room temperature after pattern exposure. FIG. 20 is an image of observing the phase transition behavior of the sample after pattern exposure (polymerization conditions; 0.1 mW / cm 2,80 ° C., 10 min. Cell gap; 3.0 μm, interference filter; λ = 550 nm). FIG. 21 is a schematic diagram of the mechanism by which the spiral axis orientation is controlled in-plane. FIG. 22 is a schematic diagram of the mechanism by which the spiral axis orientation is controlled in-plane. FIG. 23 is a schematic diagram of the mechanism by which the spiral axis orientation is controlled in-plane. FIG. 24 is an explanatory diagram of a hologram manufacturing process. FIG. 25 is an explanatory diagram of a hologram manufacturing process. FIG. 26 is an explanatory diagram of a three-dimensional spiral axis arrangement.

<1. Outline of liquid crystal element and manufacturing method of liquid crystal element>
In recent years, a material that functions as an optical element such as a lens has been developed by using a soft material such as a polymer, even though it is a thin film having a thickness of about several μm. The key technology for realizing a thin-film optical element is a method of controlling the arrangement of molecules in a polymer material. A polymer material having a molecular orientation structure that is precisely designed two-dimensionally functions as a variety of optical elements depending on the orientation structure.

However, in the existing technology in practical use, the structure size when the molecular orientation structure is controlled two-dimensionally is about several hundred μm in principle, and the molecular orientation structure is further miniaturized (for example, on the order of several μm). The following) is required. In addition, it is difficult to increase the size of the device (integration of the orientation structure) with the existing technology.

The present inventors focused on a material called cholesteric liquid crystal as one of the methods for controlling the molecular orientation structure two-dimensionally. Cholesteric liquid crystals spontaneously form a periodic structure on the order of nm to μm in which liquid crystal molecules are spirally oriented. Cholesteric liquid crystals can exhibit various optical functions such as reflection, refraction, and diffraction.

Since the molecules of the cholesteric liquid crystal are spirally oriented, the cholesteric liquid crystal itself has a one-dimensional molecular orientation periodic structure in the spiral axis direction. Moreover, the periodic structure spontaneously formed by the cholesteric liquid crystal is much finer than the periodic structure size of the optical element based on the existing molecular orientation control technology. Therefore, if the spiral axis of the cholesteric liquid crystal can be oriented in a desired two-dimensional direction, a fine and desired two-dimensional molecular orientation structure can be obtained.

However, conventionally, there is only a cholesteric liquid crystal whose spiral axis is one-dimensionally structurally controlled, which has been a restriction on its application as an optical element. A typical example of a cholesteric liquid crystal in which the spiral axis is one-dimensionally structurally controlled is that the spiral axis is oriented in parallel with the film thickness direction of the film-shaped liquid crystal element. In this structure, the spiral axis is merely oriented in a direction parallel to the film thickness direction.

Further, in another example of the cholesteric liquid crystal whose spiral axis is one-dimensionally structurally controlled, the spiral axis is oriented in parallel with the in-plane direction (direction orthogonal to the film thickness direction) of the film-shaped liquid crystal element. (See Patent Document 1).

The present inventors focused on the latter example, that is, a structure in which the spiral axis is oriented parallel to the in-plane direction of the film-shaped liquid crystal element. However, conventionally, in a structure in which the spiral axis is oriented parallel to the in-plane direction of the liquid crystal element, which direction the spiral axis faces in the in-plane direction has not been controlled. That is, in the conventional structure, the spiral axes are parallel to the in-plane direction, but the spiral axes are arranged in a random (disordered) direction in the in-plane.

A structure in which the spiral axis direction is random (disordered) in the plane is called a fingerprint-like tissue (see Patent Document 2).

It is desired to eliminate the defect in the conventional fingerprint-like tissue that the spiral axis direction is random (disordered) in the plane. By eliminating this defect, a fine and desired two-dimensional molecular orientation structure can be obtained. Devices having such a molecular orientation structure can be applied not only to the optical field but also to other fields such as application to moving materials such as actuators.

(1) In the film-shaped liquid crystal element using the cholesteric liquid crystal according to the embodiment, the spiral axis of the cholesteric liquid crystal is oriented parallel to the in-plane direction of the film-shaped liquid crystal element, and is oriented in the in-plane direction. It has a regulated first area. By restricting the orientation in the in-plane direction, the drawback that the spiral axis direction is random (disordered) in the in-plane as in the conventional fingerprint-like tissue is eliminated. Here, the in-plane direction is a direction orthogonal to the film thickness direction of the film-shaped liquid crystal element. In the film-shaped liquid crystal element, the first region may be one or a plurality. When the film-shaped liquid crystal element has a plurality of first regions, the spiral axis directions in each of the plurality of first regions may be different.

In addition, in this specification, a term indicating a direction such as parallel, orthogonal, and vertical should not be construed as meaning a strict direction, and the meaning (action effect) of the technique disclosed in this specification. It should be interpreted from the viewpoint of allowing an error within a range that does not impair.

(2) The liquid crystal element can further include a second region, which is a polymer region having an interface in contact with the first region. The interface is parallel to the film thickness direction, and may be an orientation-regulating interface for regulating the orientation of the spiral axis in the first region in the in-plane direction.

(3) The second region may be isotropic.

(4) The spiral axis in the first region is preferably oriented parallel or perpendicular to the orientation-regulating interface.

(5) In the first region, the orientation of the spiral axis is preferably regulated so as to function as an optical element. In this case, the film-shaped liquid crystal element can function as an optical element. The application of the liquid crystal element is not limited to the optical element.

(6) The optical element is preferably a diffraction optical element.

(7) The diffraction optical element is preferably a diffraction grating.

(8) The diffractive optical element is preferably a diffractive lens.

(9) The liquid crystal element using the cholesteric liquid crystal according to the embodiment includes a first region having a cholesteric liquid crystal whose molecular orientation is restricted from each of the first surface and the second surface parallel to the direction intersecting the first surface. .. The first surface and the second surface can be orthogonal to each other.

(10) In the method for producing a film-like liquid crystal element using a cholesteric liquid crystal according to the embodiment, a mixture containing a liquid crystal monomer, a chiral agent, and a photopolymerization initiator is formed on a substrate subjected to a molecular orientation treatment. By irradiating the film-like mixture with light which is arranged in a shape and has a light intensity distribution on a plane parallel to the substrate, a non-photopolymerized monomer region and a photopolymerized polymer region are formed. Includes forming.

(11) The molecular orientation treatment is preferably a vertical orientation treatment.

(12) The light intensity distribution is preferably formed by an exposure pattern. In this case, the exposure pattern can easily form a monomer region and a polymer region.

(13) When irradiating the light, the mixture is preferably set to a temperature showing an isotropic phase.

(14) The manufacturing method can further include annealing at the liquid crystal temperature after irradiation with the light.

(15) The production method can further include photopolymerizing the monomer region after the formation of the polymer region.

(16) In the method for producing a liquid crystal element according to the embodiment, a mixture containing a liquid crystal monomer, a chiral agent, and a photopolymerization initiator is irradiated with light having a light intensity distribution to form a spiral shaft of a cholesteric liquid crystal. Prepare to regulate orientation.

(17) It is preferable that the mixture is arranged on a substrate and the light is applied to the mixture arranged on the substrate.

(18) The light preferably has a light intensity distribution on a plane parallel to the substrate. In this case, a two-dimensional orientation is obtained.

(19) The light preferably has a light intensity distribution in a direction orthogonal to the substrate. In this case, a three-dimensional orientation is obtained (see FIG. 26).

(20) The light having the light intensity distribution can generate a concentration distribution of a polymer produced by photopolymerization in the mixture. The periodic structure of the liquid crystal is oriented using the concentration distribution of the polymer.

(21) The light having the light intensity distribution can cause a distribution of the phase transition temperature from the isotropic phase to the liquid crystal phase in the mixture. Using the distribution of the phase transition temperature, the periodic structure of the liquid crystal is oriented by the movement of the orientation control surface with the temperature change.

(22) In the method for producing a liquid crystal element according to an embodiment, a mixture containing a liquid crystal monomer and photopolymerized by being irradiated with light is photopolymerized in the mixture by the light intensity distribution of the irradiated light. A concentration distribution of the polymer produced by the above is generated, and the periodic structure of the liquid crystal is oriented by utilizing the concentration distribution.

(23) The method for producing a liquid crystal element according to the embodiment is isometric in the mixture according to the light intensity distribution of the irradiated light to the mixture containing a liquid crystal monomer and photopolymerization occurs when the mixture is irradiated with light. A liquid crystal element comprising generating a distribution of a phase transition temperature from a phase to a liquid crystal phase and orienting a periodic structure of a liquid crystal by utilizing the distribution of the phase transition temperature.

(23) The liquid crystal element according to the embodiment is a liquid crystal element having a periodic structure, and the periodic structure is oriented parallel to the in-plane direction of the liquid crystal element, and the orientation is restricted in the in-plane direction. It has a first area.

Orienting the periodic structure of the liquid crystal means directing the direction of the periodic structure to a desired direction. The direction of the periodic structure means the direction in which the structure changes in the periodic structure. For example, in the case of cholesteric liquid crystal, the direction of the spiral axis is the direction of the periodic structure, and in the case of smectic liquid crystal, the direction of the layer thickness is the periodic structure. Is the direction of. Orienting the periodic structure may be oriented in a two-dimensional direction or may be oriented in a three-dimensional direction. Therefore, if the direction of the periodic structure of the liquid crystal is oriented in a desired two-dimensional direction or three-dimensional direction, a fine and desired two-dimensional or three-dimensional molecular orientation structure can be obtained. Here, the direction of the periodic structure means the direction in which the structure changes in the periodic structure. For example, in the case of cholesteric liquid crystal, the direction of the spiral axis is the direction of the periodic structure, and in the case of smectic liquid crystal, the direction of the layer thickness. Is the direction of the periodic structure.

<2. Examples of liquid crystal elements and methods for manufacturing liquid crystal elements>

<2.1 First example>

FIG. 1 shows a manufacturing process of a liquid crystal element using a cholesteric liquid crystal. In the embodiment, the liquid crystal element is, for example, a film-like element. First, a raw material monomer (monomer mixture) is produced (step S11). FIG. 2 illustrates a list of materials that make up a monomer mixture. The monomer mixture of the embodiment contains a liquid crystal monomer, a chiral agent (chiral monomer) for inducing spiral orientation, and a photopolymerization initiator. The monomer mixture of the embodiment contains a liquid crystal monomer and is configured to cause photopolymerization when irradiated with light. As shown in FIG. 2, the monomer mixture may optionally contain a non-polymerizable liquid crystal (plasticizer). Moreover, the monomer mixture may optionally contain a cross-linking agent. As the polymerization group, not only radical polymerization but also anionic polymerization, cationic polymerization and the like can be freely selected.

The liquid crystal monomer is not limited to the structure illustrated in FIG. 2, and a liquid crystal monomer having another structure can be used. Here, the "liquid crystalline monomer" means a group of compounds having a "mesogen group" which is a functional group for exhibiting liquid crystal property and a "polymerizing group" which is a functional group for a polymerization reaction. The liquid crystal monomer may have one polymerization group, or may have a plurality of polymerization groups in view of the stability of the fine particles. For example, the mesogen group includes a phenyl group, a biphenyl group, a phenylcyclohexyl group, a bicyclohexyl group, a phenylbenzoate group, an azobenzene group, a trans group, and heteroelement derivatives and complexes thereof. Examples of the polymerization group include a vinyl group, an acrylic group, a methacrylic group, an epoxy group, an oxetane group and the like.

The chiral agent induces the helical structure of the liquid crystal. As the chiral agent, for example, the one shown in FIG. 2 is used. The chiral agent is not limited to the structure having the isosorbide skeleton illustrated in FIG. 2, and a polymerizable chiral agent having another structure can be used. Specifically, it may have an "asymmetric center", an "asymmetric axis", or an "asymmetric plane" in the molecular skeleton, and further have a polymerizable group in the same molecule. For example, a derivative in which a polymerization group is introduced into "S-811" or "R-811", which are the most widely used chiral agents, can be mentioned. The compounds having an asymmetric center are, for example, isosorbide, cholesterol, and S811. Compounds having an asymmetric axis are, for example, allen, biphenyl, and BINAP. Another example of an asymmetric axis is the intracellular helical axis. A compound having a spiral axis as an asymmetric axis is, for example, helicene. The compound having an asymmetric surface is, for example, cyclophane. In addition, the period of the helical structure of the cholesteric liquid crystal is determined by the "helical twisting power (HTP)" derived from the molecular structure of the chiral auxiliary. The higher the HTP of the chiral agent (HTP> several tens of μm ^-1 ), the more preferable it is because the reflection band can be controlled from the ultraviolet to the visible light region with a small amount (several mol% or less) of addition. The chiral agent used in the present invention may have an amount of several mol% with respect to the liquid crystal monomer, for example, an amount of 4 mol% with respect to the liquid crystal monomer. The chiral agent does not necessarily have to be polymerizable, and a non-polymerizable chiral agent may be used.

The produced monomer mixture is enclosed in a substrate cell 100 (see FIG. 3) composed of a pair of a first substrate 111 and a second substrate 112. The first substrate 111 and the second substrate 112 are made of glass, for example. The thickness of each of the first substrate 111 and the second substrate 112 is preferably 1 μm or more and 100 μm or less.

Between the first substrate 111 and the second substrate 112, a spacer 120 for securing a space 130 for containing the monomer mixture is arranged between the two substrates 111 and 112. The thickness of the spacer (thickness of the space 130; thickness of the film-like liquid crystal element formed) is preferably 1 μm or more and 100 μm or less, and more preferably 1 μm or more and 50 μm or less.

The first substrate 111 has a surface (lower surface in FIG. 3) 111A facing the second substrate 112. The second substrate 112 has a surface (upper surface in FIG. 3) 112A facing the first substrate 111. The facing surfaces 111A and 112A serve as an interface with the monomer mixture sealed in the space 130.

The facing surfaces 111A and 112A are previously subjected to molecular orientation processing for controlling the orientation of liquid crystal molecules. Due to the molecular orientation treatment, a molecular orientation regulating force (interface regulating force) is generated on the facing surfaces 111A and 112A. That is, the facing surfaces 111A and 112A function as a molecular orientation regulating interface (first molecular orientation regulating interface). The molecular orientation treatment applied to the facing surfaces 111A and 112A includes, for example, treatment with a silane coupling agent, treatment of a polymer film (for example, polyimide resin or acrylic resin) using a long-chain alkyl, or a hydrophobic substrate (containing fluorine). Chemical modification treatment methods that can control the surface free energy state, such as resin treatment and surface treatment to form polymer brushes such as homopolymers and block copolymers, and the use of substrates with similar surface states can be mentioned. Further, it is possible to change the surface state by physical treatment, and it is also possible to use a substrate having a fine uneven structure of about several tens of nm to several hundreds of μm (not only organic substances such as polymers but also inorganic substances are possible). ..

The molecular orientation regulating force (interface regulating force) generated on the facing surfaces 111A and 112A is preferably a regulating force in the out-of-plane direction (vertical direction) of the substrates 111 and 112. That is, the molecular orientation treatment includes a parallel orientation treatment (horizontal alignment treatment) that generates a regulatory force parallel to the interface and a vertical orientation treatment that generates a regulatory force perpendicular to the interface. , It is preferable that the vertical alignment treatment is performed. By generating an interface restricting force in the out-of-plane direction by the vertical alignment treatment, the liquid crystal molecules are oriented in the out-of-plane direction, and the spiral axis direction orthogonal to the orientation direction of the liquid crystal molecules becomes parallel to the in-plane direction. When an interface restricting force in the in-plane direction is generated by the parallel alignment treatment, the liquid crystal molecules are oriented in the in-plane direction and the spiral axis direction is parallel to the out-of-plane direction. The facing surfaces 111A and 112A may not be subjected to molecular orientation treatment. When the facing surfaces 111A and 112A are not subjected to the molecular orientation treatment, the orientation restrictions from the substrates 111 and 112 are reduced and become less dominant.

The out-of-plane direction here is the Z direction (vertical direction) in FIG. 3, which coincides with the thickness direction of the substrates 111 and 112 and the thickness direction of the film-like liquid crystal element to be formed. The in-plane direction is a direction (horizontal direction) in the XY plane in FIG. 3, and is a direction orthogonal to the Z direction. The in-plane direction is parallel to the planes of the opposing surfaces 111A and 112A of the substrates 111 and 112, and is also the in-plane direction of the formed film-like liquid crystal element (direction orthogonal to the thickness direction of the liquid crystal element).

The monomer mixture does not need to be sealed in the cell 100, but is formed into a thin film by spin coating or bar coating on a single substrate, and is in a coated state after the photopolymerization (step S13) described later. Processing may be performed.

Subsequently, as shown in FIG. 4, the substrate cell 100 in which the monomer mixture (polymerization sample) 20 is enclosed is irradiated with light (ultraviolet light) to cause a photopolymerization reaction in the monomer mixture (step S13). .. The light is applied to the substrate cell 100 via the photomask 200. As shown in FIGS. 3 and 4, the photomask 200 has a light-shielding portion 201 and a light-transmitting portion (non-light-shielding portion) 202 having a predetermined pattern. By irradiating the light through the photomask 200, the monomer mixture is partially exposed (pattern exposure) according to the pattern of the photomask 200.

That is, the light irradiated to the monomer mixture 20 has a spatial light intensity distribution in the in-plane direction (XY plane) by the photomask 200. In the monomer mixture 20, in the portion having high light intensity, that is, the portion exposed from the translucent portion 202, the photopolymerization reaction proceeds and the polymer region (polymer wall) 12 is formed. On the other hand, in the monomer mixture 20, in the portion where the light intensity is low, that is, the portion shaded by the light-shielding portion 201, the photopolymerization reaction (almost) does not proceed and remains in the monomer region 11.

As described above, between the substrates 111 and 112, the region corresponding to the light-shielding portion 201 is the monomer region (first region) 11, and the region corresponding to the translucent portion 202 is the polymer region (second region) 12. .. The light intensity distribution does not have to be formed by the photomask 200, and may be obtained by other means for obtaining the light intensity distribution.

At the start of pattern exposure, it is preferable that there is no disorder (defect) in molecular orientation. Therefore, it is preferable that the light irradiation in step S13 is performed at a temperature at which the monomer mixture 20 exhibits an isotropic phase (a state in which there is no liquid crystal orientation). .. It is more preferable that the temperature of the monomer mixture 20 during light irradiation is slightly higher than the liquid crystal phase-isotropic phase transition point. The polymer region 12 formed by photopolymerization is immobilized in an isotropic phase (without liquid crystal orientation).

As shown in FIG. 5, by forming the monomer region 11 and the polymer region 12, the interfaces (polymer interfaces) 12A and 12B between the two regions 11 and 12 are formed. The polymer interfaces 12A and 12B generate a molecular orientation regulating force (interface regulating force) on the liquid crystal molecules in the monomer region 11. That is, the surfaces 12A and 12B in contact with the monomer region 11 in the polymer region 12 function as a molecular orientation regulating interface (second molecular orientation regulating interface).

The second molecular orientation control interfaces 12A and 12B are planes parallel to the Z direction. In other words, the interfaces 12A and 12B intersect (orthogonally) the first molecular orientation control interfaces 111A and 112A that are parallel to the XY plane.

The molecular orientation restricting force (interface regulating force) generated at the interfaces 12A and 12B is a vertical alignment regulating force that orients the molecules perpendicularly to the interfaces 12A and 12B, or or aligns the molecules parallel to the interfaces 12A and 12B. Parallel orientation (horizontal orientation) regulatory force. When the vertical orientation regulating force is applied, the spiral axis becomes parallel to the interfaces 12A and 12B. Further, when the parallel orientation regulating force acts, the spiral axis becomes perpendicular to the interfaces 12A and 12B. The factor that determines the orientation regulating force in which direction is the surface energy of the interfaces 12A and 12B. The surface energy of the interfaces 12A and 12B is determined by the material composition of the monomer mixture 20 and the like, but almost any polymerizable material can generate either a vertical alignment regulating force or a parallel alignment regulating force. .. For example, a material having a long-chain alkyl or fluorine atom can be used to orient the liquid crystal molecules perpendicular to the interfaces 12A and 12B.

In the case of the material composition shown in FIG. 2, a vertical orientation restricting force is generated at the interfaces 12A and 12B with respect to the liquid crystal molecules, and as shown in the plan view of FIG. 6, the spiral axis is parallel to the interfaces 12A and 12B. become. On the other hand, when a parallel orientation restricting force is generated at the interfaces 12A and 12B, the spiral axis becomes perpendicular to the interfaces 12A and 12B as shown in FIG. FIG. 8 shows an example of a material composition that produces a parallel orientation regulating force.

As shown in FIG. 5, when the monomer region 11 is sandwiched between the paired second molecule orientation regulating interfaces 12A and 12B, the distance between the paired interfaces 12A and 12B is 1000 μm or more and 1 μm or less. Is preferable, and it is more preferably 200 μm or more and 10 μm or less. It is not always necessary to sandwich the regulated interfaces 12A and 12B, and if there is a single interface, an array can be formed within 2000 μm from the vicinity of the interface.

Further, since the polymer region 12 may function as an interface with respect to the monomer region, the thickness thereof, that is, the distance between the paired monomer regions 11 and 11 is preferably 1000 μm or less, and more preferably 1 μm or less. preferable.

After pattern exposure, annealing is performed at the liquid crystal temperature (step S14). The liquid crystal temperature is a temperature at which the monomer region 11 exhibits a liquid crystal phase, and is determined according to the material composition. By making the monomer region 11 into a liquid crystal phase, the spiral axes are neatly arranged as shown in FIGS. 6 and 7.

As a reference example, FIG. 9 shows how the orientation regulating force works to form a conventional cholesteric liquid crystal structure in which the spiral axis is one-dimensionally controlled. Conventionally, as shown in the reference example, the spiral axis is parallel to the film thickness direction (Z direction) or the film-shaped liquid crystal element is formed by the molecular orientation restricting force generated at the interfaces 111A and 112A of the substrates 111 and 112. Only one-dimensional control was possible to make the direction in-plane (direction parallel to the XY plane).

On the other hand, in the example disclosed as the present embodiment, as shown in FIG. 9, not only the molecular orientation regulating force generated at the interfaces 111A and 112A (first molecular orientation regulating force) but also the molecules generated at the interfaces 12A and 12B. The direction of the spiral axis can also be controlled by the orientation regulating force (second molecule orientation regulating force). Since the first molecule orientation regulating force and the second molecule orientation regulating force act in the direction of intersecting (orthogonal) with each other, the degree of freedom of control in the spiral axis direction is increased as compared with the reference example.

That is, in the example of the present disclosure, the obtained film-like liquid crystal element has a second surface (interface) 12A parallel to the first surface (interface) 111A, 112A and the direction intersecting (orthogonal) with the first surface 111A, 112A. , 12B each includes a first region 11 having a cholesteric liquid crystal whose molecular orientation is regulated. Due to the orientation restricting force from the intersecting first surfaces 111A and 112A and the second surfaces 12A and 12B, the spiral axis direction of the cholesteric liquid crystal can be freely controlled two-dimensionally in the XY plane.

When the first surfaces (interfaces) 111A and 112A have a vertical orientation restricting force, the spiral axis is oriented in the in-plane direction (direction parallel to the XY plane) of the film-like liquid crystal element. In the reference example shown in FIG. 9, the first surfaces 111A and 112A have a vertical orientation regulating force, so that the spiral axis is oriented parallel to the in-plane direction of the film-shaped liquid crystal element, but the in-plane direction (XY plane). Since the orientation is not regulated in (inside), the orientation is randomly (disordered) in the XY plane. As a result, in the reference example, a fingerprint-like tissue is formed when viewed on the XY plane.

On the other hand, in the example of the present disclosure, in addition to the orientation restricting force of the first surfaces 111A and 112A, the orientation regulating force of the second surfaces 12A and 12B regulates the orientation of the spiral axis in the XY plane. Induced self-organization occurs due to the synergistic effect of force. Therefore, as shown in FIGS. 6 and 7, a regular spiral axis arrangement in the XY plane is obtained. Further, the liquid crystal molecules are oriented evenly in the elliptical long axis direction. In the example of FIG. 6, each spiral axis is parallel to the Y direction, and a diffraction grating (diffraction optical element) having a lattice spacing corresponding to the spiral pitch d is obtained. In the example of FIG. 7, each spiral axis is parallel in the X direction, and a diffraction grating (diffraction optical element) having a lattice spacing corresponding to the spiral pitch d is obtained.

The arrangement and pattern of the second surfaces 12A and 12B that generate the second molecular orientation regulating force can be freely controlled by the light intensity distribution of the light stimulus. The light intensity distribution can be easily controlled by using a photomask or the like. Therefore, according to the present disclosure, it is possible to freely control the direction of the second molecule orientation regulating force to obtain a cholesteric liquid crystal orientation structure having a desired regular spiral axis direction. This makes it possible to induce a two-dimensional change in the refractive index in the XY plane.

Moreover, since the light intensity distribution can be easily controlled over a large area by using a photomask or the like, it is also easy to increase the area of the obtained film-shaped liquid crystal element. Therefore, it is easy to integrate the cholesteric liquid crystal oriented structure.

Now, after the annealing in step S14, post-exposure is performed as needed (step S15; see FIG. 1). Post-exposure is performed when polymerization of the monomer region 11 (fixation of the orientation of the liquid crystal structure) is required. By performing post-exposure, a film-like liquid crystal element having a polymerized whole can be obtained. The post-exposure may be omitted.

Post-exposure is performed, for example, by removing the photomask 200 and exposing the entire surface as shown in FIG. Further, the post-exposure may be performed by irradiating the substrate cell 100 with light from the surface opposite to the photomask 200 without removing the photomask 200.

FIG. 11 shows a measurement system for diffracted light generated by a film-shaped liquid crystal element (diffraction grating) obtained by the manufacturing method of the present embodiment. The liquid crystal element used here has a thickness of 5 μm. In step S12, the material composition shown in FIG. 2 (liquid crystal monomer: non-polymerizable liquid crystal = 50: 50 mol%, 5 mol parts of chiral agent and 1.0 mol part of polymerization initiator were added to this mixture). The monomer mixture was sealed in the substrate cell 100. The temperature at the time of encapsulation was 50 ° C. The temperature at the time of pattern exposure in step S13 was 55 ° C. (a temperature indicating an isotropic phase). The illuminance of the emitted light was 0.1 mW / cm ² . The irradiation time of light for pattern exposure was 10 minutes. Annealing in step S13 was performed at 60 ° C. (liquid crystal temperature) for 10 minutes.

The temperature during the post-exposure in step S14 was 40 ° C. The illuminance of the emitted light was 0.1 mW / cm ² . The irradiation time of light for post-exposure was 10 minutes.

In FIG. 11, ND indicates a Neutral Density filter, P indicates a deflector, and S indicates a liquid crystal element (diffraction grating) obtained by the manufacturing method of the present embodiment. In FIG. 11, α is a diffraction angle. The spiral axis direction of the liquid crystal element S coincides with the deflection direction. The light emitted from the laser is applied to the liquid crystal element (diffraction grating) S via the neutral density filter ND and the polarizer P. The diffracted light and transmitted light generated by the liquid crystal element S are projected on the screen. The diffracted light (up and down) and transmitted light projected on the screen are captured by the camera.

FIG. 12 shows the imaging results of diffracted light (+1st order light, -1st order light) and transmitted light. As shown in FIG. 12, the +1st order light and the -1st order light appear side by side in the spiral axis direction (vertical direction), and it was confirmed that the liquid crystal element S functions as a diffraction grating.

Further, the intensities of the +1st order light and the -1st order light changed depending on the incident polarization on the liquid crystal element S, and the polarization of the emitted light was also converted. Therefore, in the liquid crystal element S, linear polarization / circular polarization selectivity can be obtained. Further, the liquid crystal element S can also obtain polarization conversion characteristics.

FIG. 13 shows another example of the photomask 200A used in step S13. In the photomask 200A shown in FIG. 13, a translucent portion 202 is present around a plurality of rectangular light-shielding portions 201 arranged in an array. The light transmitting portion 202 is formed in a grid pattern. That is, in the translucent portion 202, a portion parallel to the X direction and a portion parallel to the Y direction intersect.

FIG. 14 shows a liquid crystal element 10 obtained by pattern exposure using the photomask 200A shown in FIG. The liquid crystal element has a monomer region (first region) 11 corresponding to the light-shielding portion 201 of the photomask 200, and a polymer region (second region) 12 corresponding to the translucent portion 202. The monomer region 11 has a rectangular shape, and the polymer region 12 has a lattice shape. The polymer region 12 is arranged so as to surround each of the monomer regions 11.

Therefore, all four sides 12A, 12B, 12C, and 12D surrounding the monomer region 11 serve as interfaces with the polymer region 12. That is, the monomer region 11 is surrounded by polymer interfaces 12A, 12B, 12C, and 12D from all sides. The polymer interfaces 12A, 12B12C, and 12D generate a molecular orientation regulating force (interface regulating force) on the liquid crystal molecules in the monomer region 11. That is, the surfaces 12A, 12B, 12C, and 12D in contact with the monomer region 11 in the polymer region 12 function as a molecular orientation regulating interface (second molecular orientation regulating interface).

The molecular orientation regulating force (interface regulating force) generated at the interfaces 12A, 12B, 12C, 12D is the vertical alignment regulating force that orients the molecule perpendicularly to the interfaces 12A, 12B, 12C, 12D, or the interface 12A, 12B. On the other hand, it is a parallel orientation regulating force that orients molecules in parallel.

In the example of FIG. 14, each interface 12A, 12B, 12C, 12D generates a vertical orientation regulating force. The liquid crystal molecules in the monomer region 11 are subject to regulatory forces according to the distance from each interface 12A, 12B, 12C, 12D. Therefore, the spiral axes are arranged so as to extend radially from the center of the square monomer region 11. Further, at the interfaces 12A, 12B, 12C, and 12D, the spiral axes are arranged concentrically from the center of the square monomer region 11 when a parallel orientation restricting force is generated.

A liquid crystal element in which the spiral axes are arranged radially or concentrically functions as a diffractive lens (diffractive optical element). The spiral pitch (spiral periodic structure) may be constant or may change in the spiral axis direction.

It is more preferable for the lens that the spiral pitch (spiral periodic structure) becomes shorter and the focal length becomes shorter from the center toward the extracorporeal direction, but the spiral pinch is constant in the radial direction. However, since the luminous flux can be narrowed down, it functions as a lens.

Further, in order to obtain radial or concentric spiral axis orientation, the shape of the light-shielding portion 201 is not limited to a rectangle. The shape of the light-shielding portion 201 may be circular or polygonal other than rectangular.

<2.2 Second example>

The second example will be described below. The points not particularly described in the second example are the same as those in the first example. FIG. 15 shows a list of materials constituting a raw material monomer (monomer mixture) for producing the liquid crystal device according to the second example. Among the materials shown in FIG. 15, they are mixed at a ratio of 1: 1 so that the total molar ratio of the liquid crystal monomer (A-CN) and the non-polymerizable liquid crystal (5CB) is 100. 1 mol% of photopolymerization initiator (PI) was added to the mixture of the liquid crystal monomer and the non-polymerizable liquid crystal. Further, 0.5 mol% of a chiral agent for expressing a cholesteric liquid crystal was added to prepare a monomer mixture (see FIG. 16). The prepared monomer mixture is an enantiotropic liquid crystal that expresses a liquid crystal phase in both the temperature raising and lowering processes.

The prepared monomer mixture is enclosed in the two glass substrates shown in FIG. The surface of the glass substrate is silane-coupled. By the silane coupling treatment, the surface of the glass substrate becomes an orientation-regulating surface that orients the liquid crystal molecules perpendicularly to the surface of the glass substrate. The treatment applied to the substrate is not limited to the vertical alignment treatment such as the silane coupling treatment, and may be a parallel orientation treatment (horizontal alignment treatment) such as a rubbing treatment. Further, the substrate may not be oriented.

A spacer is arranged between the two glass substrates to secure a space for containing the monomer mixture. A monomer mixture (sample) is infiltrated into the space between the glass substrates by using the capillary phenomenon. The temperature of the monomer mixture during permeation was set to 60 ° C. at which the monomer mixture showed an isotropic phase (see FIG. 18). Then, it was heated to 80 ° C. and irradiated with ultraviolet light (λ = 365 mm) having ^{a light intensity of 0.1 mW / cm 2 through a photomask to perform pattern exposure.} The pattern exposure was performed at 80 ° C. for 10 minutes. 80 ° C. is the temperature at which the homopolymer P-CN of the liquid crystal monomer A-CN exhibits a liquid crystal phase. As shown in FIG. 17, the photomask has a linear translucent portion 202. The width of the linear translucent portion 202 was set to 650 μm.

Then, the photomask was removed, the temperature of the monomer mixture was lowered to 30 ° C. showing the liquid crystal phase, and the entire surface was exposed at 30 ° C. for 10 minutes to complete the photopolymerization.

FIG. 19 shows the results of polarizing microscope observation of the sample at room temperature after pattern exposure. In FIG. 19, P is a polarizer and A is an analyzer. As shown in FIG. 19, a striped periodic structure was observed in the region A near the boundary between the light-shielding portion (non-irradiated region in the sample) and the translucent portion (irradiated region in the sample; exposed region) of the photomask. ..

In the irradiated area of the sample, a polydomain structure was observed in the range away from the area A near the boundary. It is considered that this is because the local most stable liquid crystal phase was expressed with the polymerization due to the polymerization at the isotropic phase temperature. On the other hand, in the region A near the boundary, a periodic structure of stripes was spontaneously formed along the boundary. This indicates that the spiral axis orientation was controlled in-plane by the light intensity distribution by pattern exposure.

In order to examine the observed striped structure in detail, the phase transition behavior of the sample after pattern exposure was observed. The phase transition behavior was observed by using a sample before the molecular orientation was fixed by photopolymerization (full exposure) by post-exposure, and allowing the sample to cool every 10 ° C. in a temperature range of 90 ° C. to 30 ° C.

FIG. 20 shows the results of observing the phase transition behavior of the sample after pattern exposure. When the temperature of the sample is 90 ° C., both the non-irradiated region and the irradiated region have a dark field and do not show optical anisotropy, and it is considered that both regions have an isotropic phase transition. Next, when the sample was allowed to cool to 80 ° C., a polydomain structure in which molecules were randomly oriented was observed in the central part of the irradiation region, and a slightly striped structure was observed from the translucent part to the light-shielding part near the boundary of the photomask. It was observed. From this, it is considered that in the second example, the striped structure is formed in the temperature lowering process after the pattern exposure. At this time, the liquid crystal phase was developed in the light-shielded portion despite the temperature higher than the transparent point of the monomer mixture. It is considered that this is because the polymer flows into the light-shielding portion due to the mutual diffusion between the polymer generated in the light-transmitting portion (exposure portion) and the monomer of the light-shielding portion during pattern exposure, and the liquid crystal phase is polymer-stabilized.

Next, when the sample was gradually allowed to cool to 30 ° C, the liquid crystal phase gradually appeared from the irradiated region toward the non-irradiated region. It is considered that this is because the mutual diffusion of the polymer and the monomer during the pattern exposure causes a concentration gradient of the polymer from the irradiated region to the non-irradiated region. From this result, it was suggested that the striped structure was formed along the region where the polymer concentration gradient was generated, and that the molecular diffusion during pattern exposure and the resulting polymer concentration gradient were important. ..

In addition, as a result of observing the central part of the light-shielded part of the sample after the polymerization was completed by full exposure, a fingerprint-like structure in which the spiral axis arrangement was random in the plane was observed, but a striped structure was not formed. From this result, the striped structure is formed along the region where the polymer concentration gradient is generated, and the molecular diffusion during pattern exposure and the resulting polymer concentration gradient are important for the in-plane uniaxial orientation of the spiral axis. It became clear that. Furthermore, since the striped structure expands toward the light-shielding portion along with the phase transition in the temperature lowering process, it can be seen that the directional liquid crystal phase transition phenomenon is important for the orientation of the periodic structure such as the spiral axis.

The sample immediately after pattern exposure was rapidly cooled to around 30 ° C. using liquid nitrogen, and the sample obtained after full exposure was observed with a polarizing microscope at room temperature. As a result of quenching the sample immediately after pattern exposure with liquid nitrogen, no striped structure was observed near the boundary of the photomask. Therefore, it is considered that this striped structure is formed not in the polymerization process but in the temperature lowering process after pattern exposure. On the other hand, as described above, a striped structure was formed in the sample cooled at every 10 ° C. after pattern exposure. Therefore, in the second example, the formation of the striped structure depends on the rate of temperature change. Then, it can be seen that the temperature drop rate depends.

As mentioned above, it was suggested that the concentration gradient of the polymer caused by the mutual diffusion of the polymer and the monomer during pattern exposure is important for the in-plane uniaxial orientation of the spiral axis. Therefore, the present inventors changed the polymerization conditions during pattern exposure and investigated the effect of molecular diffusion on the formation of striped structures. As a result, a striped structure was formed more widely in the sample exposed to the pattern under conditions where molecular diffusion was likely to occur. From the above results, it can be seen that this striped structure is formed along the region where the polymer concentration gradient is generated, and the polymer concentration gradient generated by molecular diffusion during pattern exposure is important.

As described above, by pattern exposure of the monomer mixture showing the cholesteric liquid crystal in the isotropic phase, a striped structure derived from the in-plane uniaxial orientation of the spiral axis was formed. 21 to 23 show the mechanism of striped structure formation.

First, as shown in FIG. 21, when pattern exposure is performed using a photomask at a temperature at which the monomer mixture exhibits an isotropic phase, a light intensity component is generated, and a polymerization reaction occurs only in a region irradiated with light. Therefore, a gradient of chemical potential is generated between the polymerized region and the non-polymerized region. As a result, mutual diffusion of the polymer and the monomer is induced in the direction perpendicular to the boundary of these regions (horizontal direction in FIG. 21), and finally a concentration gradient of the polymer is generated from the translucent portion to the light-shielding portion. It can also be considered that the pattern exposure caused a phase transition temperature gradient from the isotropic phase to the liquid crystal phase from the translucent portion to the light-shielding portion.

Next, as shown in FIG. 22, when the sample after the pattern exposure is gradually allowed to cool, the phase from the translucent portion to the light-shielding portion becomes the liquid crystal phase due to the concentration gradient of the polymer generated in the step shown in FIG. Transition occurs gradually. At this time, the region where the phase transition occurs in a specific temperature range (ΔT) due to the concentration gradient of the generated polymer becomes very narrow in the left-right direction of FIG. As a result, the molecular orientation is controlled in one direction because the induced self-organization phenomenon of the liquid crystal occurs as the guiding structure (Guiding Structure) by using this difference in the phase transition temperature. This can be thought of as a phenomenon similar to crystal growth along the temperature gradient direction.

In this way, the boundary between the region where the liquid crystal phase is expressed and the region where the liquid crystal molecules are reoriented function as the molecular orientation control interface. At this time, the molecular orientation is controlled horizontally with respect to the regulation interface by the affinity between the liquid crystal molecules that are reoriented and the boundary. It can also be considered that the horizontally oriented regulatory interface moved along the polymer concentration gradient direction (direction from right to left in FIG. 22) in the temperature lowering process.

Finally, as shown in FIG. 23, in the process shown in FIG. 22, the in-plane uniaxial orientation of the spiral axis is formed by the combination of the molecular orientation controlled by the induced self-organization and the spiral-inducing force of the chiral auxiliary. .. At this time, since the spiral axis of the cholesteric liquid crystal is oriented only in the direction perpendicular to the regulation interface of horizontal orientation, the in-plane uniaxial orientation of the spiral axis along the concentration gradient of the polymer is achieved. However, control of the spiral axis orientation is not achieved in the central portion of the light-shielding portion (the left region in FIG. 23). It is considered that this is because the concentration gradient of the polymer does not occur, the phase transition temperature is uniform in the central part of the light-shielding portion, and self-assembly occurs randomly.

In the second example, a photomask was used to obtain a light intensity distribution, but the means for obtaining the light intensity distribution may be a light source having a light intensity distribution or the like. Further, a light intensity distribution may be obtained by using a photomask in which the light transmittance changes stepwise.

In the above-mentioned second example, the spiral axis orientation (orientation of the periodic structure) occurred in the temperature lowering process, but the temperature lowering process is not essential in the spiral axis orientation (orientation of the periodic structure). If the polymerization system can be changed and the liquid crystal phase transition can be gradually induced from the region where the polymer concentration is high in the polymerization process, even if there is no temperature lowering process, it depends on the concentration distribution of the polymer, as in the second example. It is also possible to cause a phase transition from an isotropic phase to a liquid crystal phase.

FIGS. 24 and 25 show an example of manufacturing a hologram arrangement pattern using a polymer concentration gradient. FIG. 24 shows the first step in the production example of the hologram arrangement pattern using the polymer concentration gradient. In the first step, a photomask for patterning the hologram compartment is used. The photomask of FIG. 24 includes eight light-shielding portions, and a light-transmitting portion is formed around the light-shielding portions. The spacing between the light-shielding portions is arbitrary, but the smaller the spacing, the higher the fill-factor of the high-efficiency hologram.

When the sample (monomer mixture) is irradiated with ultraviolet light through the photomask of FIG. 24, a polymer frame for partitioning eight monomer regions (hologram compartments) is formed as shown in FIG. 24. .. In the first step, since strong ultraviolet light is irradiated for a short time, only a polymer frame having an extremely high polymer concentration is formed, and it does not participate in the spiral axis orientation.

FIG. 25 shows the second step in the production example of the hologram arrangement pattern using the polymer concentration gradient. In the second step, a photomask for forming a hologram is used. The photomask of FIG. 25 has eight regions corresponding to each of the eight hologram compartments, and each region has a gradient light transmittance.

When the sample after the first step is irradiated with ultraviolet light through the photomask of FIG. 25, a gradient light intensity distribution is generated in each of the eight hologram compartments, and as a result, the sample is gradient. A polymer concentration gradient occurs. As a result, a hologram having a spiral axis oriented in the polymer concentration gradient direction is obtained.

The polymer concentration gradient can be used not only for in-plane two-dimensional orientation but also for three-dimensional orientation. FIG. 26 shows an example of the three-dimensional orientation of the spiral axis. In this example, a light source that irradiates a Gaussian beam is used. The Gaussian beam has a Gaussian distribution in the light intensity distribution in the plane perpendicular to the optical axis. That is, the light intensity of the Gaussian beam decreases as the distance from the optical axis increases in the plane perpendicular to the optical axis. Further, the sample (monomer mixture) contains a dye or the like that absorbs light, and the light intensity decreases as the distance from the light source increases. In this case, a hemispherical light intensity distribution occurs in the sample with the light source as the center and the light intensity decreases as the distance from the light source increases three-dimensionally. The result is a three-dimensional hemispherical polymer concentration gradient in the sample. Therefore, a three-dimensional spiral axis array in which the spiral axes are oriented along the radial direction of the hemisphere is obtained. In this way, the three-dimensional spiral axis arrangement is suitable for angle-independent reflective materials.

<3. Addendum>
The present invention is not limited to the above embodiment, and various modifications are possible.

10: Liquid crystal element (film-like element)
11: First region (monomer region)
12: Second region (polymer region)
12A: Second molecular orientation control interface (polymer interface; second surface)
12B: Second molecular orientation control interface (polymer interface; second surface)
12C: Second molecular orientation control interface (polymer interface; second surface)
12D: Second molecular orientation control interface (polymer interface; second surface)
20: Monomer mixture 100: Substrate cell 111: First substrate 111A: First molecular orientation control interface (substrate interface; first surface)
112: Second substrate 112A: First molecular orientation control interface (board interface; first surface)
120: Spacer 130: Space 200: Photomask 200A: Photomask 201: Light-shielding part 202: Transmissive part ND: Filter P: Polarizer S: Liquid crystal element (film-like element)

Claims (24)

1. A film-like liquid crystal element using a cholesteric liquid crystal.
   A film-shaped liquid crystal element using a cholesteric liquid crystal in which the spiral axis of the cholesteric liquid crystal is oriented parallel to the in-plane direction of the liquid crystal element and has a first region whose orientation is restricted in the in-plane direction.
2. A second region, which is a polymer region having an interface in contact with the first region, is further provided.
   The film-like interface using the cholesteric liquid crystal according to claim 1, which is parallel to the film thickness direction and is an orientation-regulating interface for regulating the orientation of the spiral axis in the first region in the in-plane direction. Liquid crystal element.
3. The second region is a film-shaped liquid crystal element using the cholesteric liquid crystal according to claim 2, which is an isotropic phase.
4. The film-shaped liquid crystal element using the cholesteric liquid crystal according to claim 2 or 3, wherein the spiral axis in the first region is oriented parallel or perpendicular to the orientation-regulating interface.
5. The first region is a film-shaped liquid crystal element using the cholesteric liquid crystal according to any one of claims 1 to 4, wherein the orientation of the spiral axis is regulated so as to function as an optical element.
6. The optical element is a film-shaped liquid crystal element using the cholesteric liquid crystal according to claim 5, which is a diffractive optical element.
7. The diffractive optical element is a film-shaped liquid crystal element using the cholesteric liquid crystal according to claim 6, which is a diffraction grating.
8. The diffractive optical element is a film-shaped liquid crystal element using the cholesteric liquid crystal according to claim 6, which is a diffractive lens.
9. A liquid crystal element comprising a first region having a cholesteric liquid crystal whose molecular orientation is regulated from each of a first surface and a second surface parallel to the direction intersecting the first surface.
10. A method for manufacturing a film-like liquid crystal element using a cholesteric liquid crystal.
    A mixture containing a liquid crystal monomer, a chiral agent, and a photopolymerization initiator is arranged in a film form on a substrate subjected to a molecular orientation treatment.
    By irradiating the film-like mixture with light having a light intensity distribution on a plane parallel to the substrate, a non-photopolymerized monomer region and a photopolymerized polymer region are formed.
    A method for manufacturing a liquid crystal element using a cholesteric liquid crystal.
11. The method for manufacturing a liquid crystal element using a cholesteric liquid crystal according to claim 10, wherein the molecular orientation treatment is a vertical orientation treatment.
12. The method for manufacturing a liquid crystal element using a cholesteric liquid crystal according to claim 10 or 11, wherein the light intensity distribution is formed by an exposure pattern.
13. The method for manufacturing a liquid crystal element using a cholesteric liquid crystal according to any one of claims 10 to 12, wherein the mixture is set to a temperature indicating an isotropic phase when irradiated with the light.
14. The method for manufacturing a liquid crystal element using a cholesteric liquid crystal according to any one of claims 10 to 13, further comprising annealing at a liquid crystal temperature after irradiation with light.
15. The method for producing a liquid crystal device using a cholesteric liquid crystal according to any one of claims 10 to 14, further comprising photopolymerizing the monomer region after forming the polymer region.
16. A method for manufacturing a liquid crystal element, which comprises regulating the orientation of the spiral axis of a cholesteric liquid crystal by irradiating a mixture containing a liquid crystal monomer, a chiral agent, and a photopolymerization initiator with light having a light intensity distribution.
17. The mixture is placed on the substrate and
    The method for manufacturing a liquid crystal element according to claim 16, wherein the light is applied to the mixture arranged on the substrate.
18. The method for manufacturing a liquid crystal element according to claim 17, wherein the light has a light intensity distribution on a plane parallel to the substrate.
19. The method for manufacturing a liquid crystal element according to claim 18, wherein the light further has a light intensity distribution in a direction orthogonal to the substrate.
20. The method for producing a liquid crystal element according to any one of claims 16 to 19, wherein the light having the light intensity distribution causes a concentration distribution of a polymer produced by photopolymerization in the mixture.
21. The production of the liquid crystal element according to any one of claims 16 to 20, wherein the light having the light intensity distribution causes a distribution of a phase transition temperature from an isotropic phase to a liquid crystal phase in the mixture. Method.
22. The light intensity distribution of the light irradiated to the mixture containing the liquid crystal monomer and causing photopolymerization by irradiation with light causes a concentration distribution of the polymer produced by photopolymerization in the mixture.
    A method for manufacturing a liquid crystal device, which comprises orienting a periodic structure of a liquid crystal using the concentration distribution.
23. The light intensity distribution of the light irradiated to the mixture containing the liquid crystal monomer and photopolymerization occurs when the mixture is irradiated with light causes the distribution of the phase transition temperature from the isotropic phase to the liquid crystal phase in the mixture. ,
    A method for manufacturing a liquid crystal device, which comprises orienting a periodic structure of a liquid crystal using the distribution of the phase transition temperature.
24. A liquid crystal element having a periodic structure
    A liquid crystal element having a first region whose periodic structure is oriented parallel to the in-plane direction of the liquid crystal element and whose orientation is restricted in the in-plane direction.

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