JP2000029035A - Liquid crystal element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element which is not affected by hardness or softness of substrates compared with a conventional liquid crystal element, to be able to keep liquid crystal layer thickness constant over a long period and to stably obtain a desired contrast and reflectance thereby. SOLUTION: A liquid crystal element is equipped with the first and the second substrates 1a and 1b, at least one of which is transparent, disposed to face oppositely, a plurality of columnar structural bodies 2 provided between the substrates 1a and 1b, and liquid crystal 3 enclosed within a space between the columnar structural bodies 2 provided between the substrates 1a and 1b. The columnar structural bodies 2 are formed with photoresist obtained from a photoresist material with 10-15 SP value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device in which a columnar structure and a liquid crystal are arranged between a pair of substrates, at least one of which is transparent, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a liquid crystal device in which liquid crystal is sealed between a pair of substrates, in order to obtain a predetermined contrast, a predetermined reflectance, and the like at a predetermined driving voltage, it is necessary to keep the substrate gap, that is, the thickness of the liquid crystal constant. is important. In order to keep the substrate gap constant, a large number of granular spacers made of a material such as plastic or glass are sandwiched between the two substrates. The spacer is used in such a manner that the spacer is sprayed on one of the substrates before assembling the substrate, or is mixed in the liquid crystal material in advance.

[0003] However, it is technically difficult to uniformly spray a large number of spacers over a desired area range. In the case where at least one of the pair of substrates is a flexible film or sheet, the thickness of the liquid crystal layer partially changes due to the pressure applied to the substrate surface only by holding the spacer between the substrates. Display is easy to change. Also,
With the method using spacers, it is difficult to keep the liquid crystal layer in a predetermined shape for a long time. Therefore, it has been proposed to form a wall-shaped structure made of, for example, resin having a predetermined thickness between liquid crystal regions in a substrate gap.

For example, according to Japanese Patent Application Laid-Open No. 62-203123, in a liquid crystal element in which liquid crystal is sealed between a pair of flexible substrates with electrodes, a weir made of a polymer having a uniform thickness and continuous in a matrix is provided between the substrates. There is disclosed a liquid crystal element in which liquid crystals are independently sealed in a plurality of cells which are fixed and separated from each other by the weir. This eliminates the need to seal the periphery of the substrate in order to prevent leakage of liquid crystal from the periphery of the substrate, and cuts a large or long formed liquid crystal element to an arbitrary size or shape. It is said that a liquid crystal element of the above can be obtained.

[0005]

However, in the liquid crystal device disclosed in Japanese Patent Application Laid-Open No. 62-203123, depending on the kind of the polymer substance which is the material of the weir (wall-like structure), the polymer is contained in the liquid crystal. The substance is melted, thereby impairing the properties of the liquid crystal and changing the shape of the wall-like structure over time. When the shape of the wall-like structure is broken, the distance between the substrates changes. In these cases, sufficient contrast and reflectance cannot be obtained. Another drawback is that the drive voltage required to operate the liquid crystal is not uniform over the entire liquid crystal area, and therefore the drive voltage must be increased to operate the entire liquid crystal area in the same manner.

Accordingly, the present invention provides a liquid crystal device in which liquid crystal is sealed between a pair of transparent substrates, at least one of which is not affected by the hardness of the substrate as compared with the conventional device.
It is an object of the present invention to provide a liquid crystal element in which the thickness of a liquid crystal layer can be kept constant over a long period of time, whereby a desired contrast and reflectance can be stably obtained, and a simple manufacturing method thereof.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted repeated studies and obtained the following findings. When at least one of the substrates is made of a flexible material, in order to keep the substrate interval at a predetermined interval, a plurality of columnar structures are formed between a pair of substrates, and a space between the columnar structures is formed. What is necessary is just to fill a liquid crystal. For example, a photoresist is adopted as a material of the columnar structure, a photoresist material is applied on one substrate to a predetermined thickness, and the coating film is exposed through a predetermined photomask,
By developing the columnar structure made of photoresist, a columnar structure having a desired height can be obtained without using a spacer. In addition, an extremely accurate columnar structure can be obtained by a method of exposing through a photomask. There is a solubility parameter SP as a main parameter indicating the interaction between a polymer substance and a liquid such as a solvent, and when a polymer substance obtained from a material having an SP value of 10 to 15 is used as a material for the columnar structure, the liquid crystal has Dissolution of the polymer material into the columnar structure becomes negligible, and the shape of the columnar structure can be kept constant. As a result, the thickness of the liquid crystal phase can be kept constant.

[0008] Based on the above knowledge, the present invention provides a first and second substrates, at least one of which is transparent, opposed to each other, a plurality of columnar structures provided between the substrates, and the columnar structure between the substrates. And a liquid crystal sealed in a space between the structures, wherein the columnar structure is formed of a polymer material obtained from a material having an SP value of 10 to 15. I do.

According to the liquid crystal device of the present invention, a plurality of columnar structures made of a polymer material are formed in advance between a pair of substrates, and the liquid crystal is held in a region between the columnar structures. Even when one is made of a flexible material, the distance between the substrates can be kept at a predetermined distance. Also, no spacer is required to maintain the substrate-to-substrate spacing. Also, the liquid crystal generally has a solubility parameter SP
Is 8 or less, the polymer constituting the columnar structure in the liquid crystal device of the present invention has a solubility parameter S
Since the value of P is obtained from a material in the range of 10 to 15, it is not dissolved or hardly dissolved in the liquid crystal,
The predetermined shape of the columnar structure is maintained for a long time.
Thereby, the distance between the substrate pairs, that is, the thickness of the liquid crystal layer between the substrate pairs can be kept constant, and the desired contrast and the desired reflectance can be maintained.

[0010] The SP value of a material can be measured by mixing a material to be measured with a solvent whose SP value is known in advance and determining whether or not they are compatible with each other. When the SP value of the material for obtaining the polymer substance becomes smaller than 10, the SP value of the liquid crystal becomes close to the SP value of the liquid crystal, and the polymer substance constituting the columnar structure is easily dissolved in the liquid crystal. The SP value is 1
When it is larger than 5, the hygroscopicity of the polymer substance increases, and the columnar structure absorbs moisture, so that the liquid crystal performance tends to decrease.

Although the kind of the polymer substance is not particularly limited, a desired substrate interval can be easily obtained by employing a photoresist. Further, based on the above knowledge, the present invention provides that the SP value is 1 on one surface of the first substrate.
A photoresist material application step of applying a photoresist material of 0 to 15 with a predetermined thickness, an exposure step of performing an exposure treatment on the coating film of the photoresist material in a predetermined exposure pattern, and after the exposure step, developing the coating film A developing step of processing to obtain a plurality of columnar structures corresponding to the exposure pattern, a substrate superimposing step of covering a second substrate from above the columnar structures and superimposing the first substrate on the first substrate, And a liquid crystal arranging step of arranging a liquid crystal between the columnar structures.

According to the method of manufacturing a liquid crystal element of the present invention, a photoresist is adopted as a material of the columnar structure, a photoresist material is applied in advance to a predetermined thickness on one of the substrates, and the coating film is exposed. Develop to get a columnar structure,
Further, a liquid crystal layer having a predetermined thickness can be formed by sandwiching the substrate on which the columnar structure is formed with a new substrate. Also,
To obtain a columnar structure by exposing and developing a photoresist material coating through a photomask having a plurality of openings so that a desired columnar structure can be obtained, an extremely accurate columnar structure corresponding to the mask shape is obtained. Obtainable.

In the present invention, the term "photoresist material" refers to a raw material for obtaining a photoresist by exposure and development, and the term "photoresist" refers to a material obtained by exposing and developing a photoresist material. In the case of the negative type, the photoresist material is a low molecular weight monomer or (and) oligomer, and the exposed portion is polymerized by polymerizing, and the unexposed portion is removed by development. In the case of the positive type, the photoresist material is a polymer substance, and the exposed portion has increased solubility in an alkaline developer, and the exposed portion is removed by development, and the unexposed portion remains as a polymer material.

In the liquid crystal element and the method of manufacturing the same according to the present invention, the columnar structure has a polygonal shape such as a circular or square cross section.
Any shape such as a wall plate shape may be used. In any case, a continuous liquid crystal region is formed between the substrates. The height of the columnar structure depends on the diameter of each columnar structure, the distribution density of the columnar structure, etc., but is too high for sealing the liquid crystal between the two substrates with a predetermined thickness. In order not to be easily buckled by a load from the outside, it is not limited thereto, but may be about 3 μm to 20 μm, more preferably about 5 μm to 15 μm.

If the ratio of the area occupied by the columnar structure (columnar structure) in the light modulation region of the observation surface when viewed from the transparent substrate side is 0.5% or more (99.5% aperture ratio), the liquid crystal The minimum required strength as an element can be obtained. As the ratio of the area occupied by the columnar structures in the light modulation region increases, the area of the light modulation portion decreases. However, if the ratio is 40% or less (aperture ratio of 60%), the characteristics are sufficient for practical use as a liquid crystal element. Is obtained. In consideration of the above, the size of the columnar structure (columnar structure) in the width direction is 2 μm to 2 μm.
The distance between the pillars can be about 50 μm, and the distance between the pillars can be about 3 μm to about 1000 μm.

In order to prevent liquid crystal leakage between the peripheral portions of the two substrates, a part of the columnar structure may be formed as a sealing wall extending between the peripheral portions of the two substrates. Alternatively, a sealing wall separately formed with a sealing agent such as a resin may be provided. The sealing wall also serves as an adhesive for bonding the substrate pair. In this case, as the sealing agent, a sealing agent containing a large number of spacers, such as particles, may be employed.

Further, in the liquid crystal device of the present invention, each of the first and second substrates may include an electrode for applying a drive voltage. In this case, for example, the two substrates can be arranged to face each other such that the electrodes face each other. Also, in the method of manufacturing a liquid crystal element of the present invention, the first and second substrates each having an electrode can be employed. In this case, for example, the photoresist material is applied on the electrode forming surface of the first substrate, and the second substrate is covered with the electrode forming surface of the first substrate facing the columnar structure. As shown in FIG. Note that the first and second
Even when electrodes are not provided on at least one of the substrates, display can be performed by applying a driving voltage to liquid crystal between the two substrates using, for example, external electrodes.

Further, whether or not a substrate with electrodes is used as the first and second substrates, an electric current is provided between the columnar structure and the first and / or second substrate. An insulating film may be formed. When a substrate with electrodes is used as the first and second substrates, providing an electrically insulating film helps prevent an electrical short circuit between the two substrates. The electrically insulating film can be formed, for example, on the electrode formation surface of at least one substrate.

Further, an alignment film may be formed between the columnar structure and the first and / or second substrate. When the alignment film is provided, the liquid crystal can be aligned in a predetermined fixed direction. The alignment film may also serve as an electric insulating film.
It may also serve as an adhesive for bonding the columnar structure and the substrate. The alignment film may be formed on the surface of the first substrate on which the columnar structure is to be formed or (and / or) on the surface of the second substrate facing the columnar structure. Also, a columnar structure is formed on a first substrate, and an alignment film is provided on the columnar structure. On the other hand, a substrate on which a similar alignment film is formed on one surface of a second substrate is prepared. Can be bonded at a high temperature, so that the alignment film can also serve as an adhesive.

In the method of the present invention, the exposure treatment in the exposure step is not limited to the above. For example, the photoresist material coating film may be formed using a photomask having an exposure opening formed so as to form the columnar structure. Covering is performed by irradiating the coating film with predetermined light from above the mask. For the exposure and development treatment, the exposed photoresist material coating is brought into contact with a developing solution, and depending on whether the photoresist material is a positive type or a negative type, an exposed portion or an unexposed portion is dissolved and removed. You can do that.

In the method of the present invention, the photoresist film may be subjected to a pre-baking treatment at a predetermined temperature and time before the exposure step. By performing the pre-baking process, the organic solvent in the photoresist material can be removed. Further, after the exposure step and before the development step, the coating film may be subjected to a post-exposure baking treatment at a predetermined temperature and a predetermined time. Thus, by performing the baking treatment on the photoresist material coating after exposure,
Pattern formation by exposure can be completed.

Further, if necessary, after the developing step and before the substrate overlapping step and the liquid crystal disposing step,
The columnar structure obtained by the developing step may be subjected to a post exposure treatment and a post baking treatment. The post exposure treatment may be performed on the entire first substrate on which the columnar structures are formed. By performing post exposure processing,
It is possible to suppress an additive such as a photosensitizer or a reaction accelerator in the photoresist from flowing into the liquid crystal, and to suppress a decrease in liquid crystal performance due to the additive. Further, by performing the post exposure treatment and the post baking treatment, the adhesion between the first substrate and the columnar structure can be improved.

In the method of the present invention, the liquid crystal may be sealed between the two substrates after the second substrate is provided on the first substrate on which the columnar structures are formed. After the region between the columnar structures is filled with the liquid crystal, a second substrate may be overlaid thereon, and the columnar structure and the liquid crystal may be sandwiched between the first and second substrates.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal device according to one embodiment of the present invention has first and second substrates with electrodes, at least one of which is transparent. The substrates are arranged so that the electrodes face each other. Also, a plurality of columnar structures are formed between the substrates. The plurality of columnar structures are SP
It is composed of a polymer substance obtained from a material having a value of 10 to 15. Liquid crystal is sealed in a space between the columnar structures between the substrates.

The liquid crystal device according to the embodiment of the present invention can be manufactured, for example, as follows. A photoresist is adopted as the polymer substance. First, a photoresist material having an SP value of 10 to 15 is applied to a predetermined thickness on the electrode forming surface of the first electrode-attached substrate. The application of the photoresist material can be performed by a known method such as a spin coating method. The photoresist material is uniformly applied so as to form a thick film having a thickness of about 3 μm to 20 μm, more preferably about 5 μm to 15 μm.

The "substrate" in the present invention is a concept including a flexible or poorly flexible plate-like member, a flexible film, and the like. For example, one of a pair of substrates is used. It is also conceivable that it is a plate having a hardness enough to hold the composite film, and the other is a film, for example, for protecting the composite film. Of course, both the first and second substrates may be made of a flexible material such as a film.

It is sufficient that at least the substrate with electrodes on the liquid crystal element observation side of the first and second substrates with electrodes has a transparent electrode formed on a transparent substrate. As a material of the transparent substrate, for example, a resin such as polyethylene terephthalate, polycarbonate, polyether sulfone, glass, or the like can be adopted. As a transparent electrode, ITO (Indium Tin Oxi
de), an electrode made of a material such as SnO ₂ or InO ₃ , an electrode made of a thin metal film, or the like can be used.

Next, the coating of the photoresist material is covered with a photomask capable of forming a desired columnar structure, and the coating is irradiated with predetermined light corresponding to the photoresist material from outside the mask. In addition, before exposure or (and)
After the exposure and before the development, the photoresist material coating may be subjected to a baking treatment. The baking (pre-baking) treatment before exposure can be specifically performed by placing a substrate coated with a photoresist material on a hot plate. The heating temperature at this time can be, for example, 100 ° C. or higher. Baking after exposure (post-exposure baking)
In the same manner, the exposed substrate with the resist
It can be carried out by placing it on a hot plate at 0 ° C. or higher.

Then, the exposed coating film is brought into contact with the developer by immersing it in a developer or the like, and the exposed or unexposed portion is removed by dissolving or the like, depending on whether the photoresist material is a positive type or a negative type. Furthermore, the developed coating film is washed with pure water or the like,
dry. Thereby, a columnar structure corresponding to the mask shape is obtained. Thereafter, post-exposure and post-baking may be performed as necessary. The post-exposure process refers to a process of exposing the entire resist-coated substrate patterned into a columnar structure. By performing the post exposure, the adhesion between the substrate and the resist can be increased.
In addition, the post-baking treatment can be specifically performed by placing the substrate with the resist after the post-exposure on a hot plate. The heating temperature at this time can be, for example, 100 ° C. or higher. Post-baking improves the adhesion between the substrate and the resist.

Next, the second electrode-attached substrate is overlaid thereon with its electrode formation surface facing the columnar structure, and the columnar structure is sandwiched between the first electrode-attached substrate and the second electrode-attached substrate. . Next, the liquid crystal injection port is left, and the periphery of the first and second substrates is sealed using a sealing agent such as a resin. At the same time as the formation of the columnar structure, a sealing wall may be formed on the peripheral portion of the first substrate using the same photoresist material.

A liquid crystal element is obtained by vacuum-injecting the liquid crystal from the injection port of the empty cell thus obtained. The type of liquid crystal is not particularly limited, and nematic liquid crystal,
Any of a smectic liquid crystal, a liquid crystal exhibiting a cholesteric phase (a cholesteric liquid crystal, a chiral nematic liquid crystal in which a chiral material is added to a nematic liquid crystal so as to obtain a predetermined helical pitch, and the like) can be used.

FIG. 1 shows a cross section of an example of the liquid crystal element of the embodiment of the present invention obtained in this way. This liquid crystal element comprises a substrate 1a with a first electrode and a substrate 1b with a second electrode.
, And both substrates are arranged so that the electrodes face each other. The SP value is between 10 and 15 between the substrates 1a and 1b.
A plurality of columnar structures 2 made of a photoresist obtained from the above photoresist material are formed on the substrate 1a, 1b.
The space between the columnar structures 2 is filled with liquid crystal 3. Further, a sealing wall 4 made of a polymer is formed at a peripheral portion between the substrates 1a and 1b.

According to this liquid crystal element, the substrate pair 1a, 1b
A plurality of columnar structures 2 are previously formed between the columnar structures 2
Since the liquid crystal 3 is held in the region between the two, the substrate pair 1a,
Even when at least one of 1b is made of a flexible material, the substrate-to-substrate distance can be kept at a predetermined distance. Further, since the photoresist material for obtaining the photoresist constituting the columnar structure 2 has a solubility parameter SP in the range of 10 to 15, the photoresist columnar structure obtained therefrom usually has a liquid crystal having an SP value of 8 or less. 3
The columnar structure 2 is not dissolved or hardly dissolved, and the predetermined shape of the columnar structure 2 is maintained for a long time. Thereby, the distance between the pair of substrates 1a and 1b, that is, the thickness of the liquid crystal layer between the pair of substrates can be kept constant, and desired contrast and reflectance can be maintained. A spacer is not particularly necessary for maintaining the distance between the substrates, but a spacer may be used together with the formation of the columnar structure. In this case, for example, a cell can be manufactured by dispersing spacers in advance on the second substrate 1b and overlapping the first substrate 1a on which the columnar structures are formed.

Further, a photoresist is adopted as a material of the columnar structure 2, a photoresist material is previously applied to one substrate 1a at a predetermined thickness, and the coating film is exposed and developed to form the columnar structure 2. obtain. Furthermore, a new substrate 1b is superimposed on the substrate 1a on which the columnar structure 2 is formed, so that a liquid crystal layer having a predetermined thickness can be formed. In addition, since the photoresist material coating is exposed and developed through a photomask having a plurality of openings so that a desired columnar structure can be obtained, the columnar structure 2 is obtained. Structure 2
Can be obtained.

By using a resin having a small contact angle with the liquid crystal as a resin constituting the columnar structure (columnar structure), device characteristics such as driving voltage and contrast can be improved. Although it depends on the type of liquid crystal, for example, a columnar structure having a contact angle with liquid crystal of 20 ° or less, more preferably 17 ° or less can be used.

FIG. 2 shows a liquid crystal device according to another embodiment of the present invention. This liquid crystal element is different from the liquid crystal element shown in FIG. 1 in that the electrical insulating property between the first substrate 1a and the columnar structure 2 and between the second substrate 1b and the columnar structure 2 is over the area of these substrates. A film 5 is provided. Other configurations are the same as those of the liquid crystal element of FIG. 1, and the same components are denoted by the same reference numerals. According to this liquid crystal element, an electrical short circuit between the electrodes provided on the opposing surfaces of the substrates 1a and 1b is prevented.

In manufacturing this liquid crystal element, an electrically insulating film such as SiO ₂ is previously formed on the electrode forming surfaces of the substrates 1a and 1b with electrodes by a spin coating method, a vapor deposition method or the like. These electrodes and the substrates 1a, 1
Using b, a liquid crystal element is manufactured in the same manner as in the case of the liquid crystal element in FIG. FIG. 3 shows a liquid crystal device according to still another embodiment of the present invention. This liquid crystal element is different from the liquid crystal element shown in FIG. 1 in that an alignment film 6 is provided between the first substrate 1a and the columnar structure 2 and between the second substrate 1b and the columnar structure 2 over the area of these substrates. Is provided. Other configurations are the same as those of the liquid crystal element of FIG. 1, and the same components are denoted by the same reference numerals. According to this liquid crystal element, due to the presence of the alignment film 6, in the initial state, the liquid crystal molecules have an alignment state in which the major axis directions are aligned in a direction perpendicular, parallel or inclined at a certain angle to the substrate.

In manufacturing this liquid crystal element, an alignment film such as a polyimide alignment film or a polyamic acid type alignment film is previously formed on the electrode forming surfaces of the substrates 1a and 1b with electrodes by a method such as spin coating. . Using these electrodes and the substrates 1a and 1b with an alignment film, a liquid crystal element is manufactured in the same manner as in the case of the liquid crystal element of FIG. Also,
As shown in FIG. 4, between the first substrate 1a and the columnar structure 2 and between the second substrate 1b and the columnar structure 2, the electrically insulating film 5 and the alignment film 6 covering the area range of these substrates respectively. However, a liquid crystal element provided in this order can also be cited as still another embodiment of the present invention. According to this liquid crystal element, an electric short circuit between the electrodes provided on the opposing surfaces of the substrates 1a and 1b is prevented, and the liquid crystal molecules are in a predetermined alignment state in an initial state. In this liquid crystal element, an electric insulating film 5 and an alignment film 6 are previously formed on each of the electrode forming surfaces of the first and second substrates 1a and 1b, and otherwise the same as in the case of the liquid crystal element of FIG. Can be made.

As shown in FIG. 5, a liquid crystal element in which an electric insulating film 5 and an alignment film 6 are formed in this order between the first substrate 1a and the columnar structure 2 over the area of the substrate is also provided.
This can be cited as still another embodiment of the present invention. According to this liquid crystal element, like the liquid crystal element of FIG.
An electric short circuit between the electrodes provided on the opposing surfaces of the substrates 1a and 1b is prevented, and the liquid crystal molecules are in a predetermined alignment state in an initial state. This liquid crystal element
An electrical insulating film 5 and an alignment film 6 are previously formed on the electrode forming surface of the first substrate 1a, and the other components can be manufactured in the same manner as the liquid crystal element of FIG.

As shown in FIG. 6, a liquid crystal element in which an electric insulating film 5 and an orientation film 6 are formed in this order between the second substrate 1b and the columnar structure 2 over the area of the substrate is also provided.
This can be cited as still another embodiment of the present invention. According to this liquid crystal element, like the liquid crystal element of FIG.
An electric short circuit between the electrodes provided on the opposing surfaces of the substrates 1a and 1b is prevented, and the liquid crystal molecules are in a predetermined alignment state in an initial state. This liquid crystal element
An electrical insulating film 5 and an alignment film 6 are previously formed on the electrode forming surface of the second substrate 1b, and the other components can be manufactured in the same manner as the liquid crystal device of FIG.

In manufacturing the liquid crystal device shown in FIGS. 3, 4 and 6, in addition to forming an alignment film on the second substrate 1b by a method such as spin coating, the first substrate 1a The alignment film can also be formed by spray-coating the material of the alignment film on the upper surface of the columnar structure 2 formed thereon and baking at high temperature (for example, 200 ° C.). Thereafter, by bonding the alignment films of both substrates 1a and 1b at a high temperature (for example, 200 ° C.), the adhesive strength between both substrates 1a and 1b can be improved.

In driving the above-described liquid crystal element by applying a voltage, two kinds of high and low voltages are applied to switch the arrangement of liquid crystal molecules. For example, when a liquid crystal exhibiting a cholesteric phase is used, two kinds of high and low pulse voltages are applied to switch the arrangement of liquid crystal molecules between a planar arrangement and a focal conic arrangement. This state is maintained stably even after the voltage application is stopped.

A liquid crystal exhibiting a cholesteric phase selectively reflects light having a wavelength corresponding to the product of the helical pitch and the average refractive index of the liquid crystal in a planar arrangement in which the helical axis is arranged perpendicular to the substrate. Therefore, if liquid crystals having selective reflection wavelengths in, for example, the red, blue, and green regions are used, light of each wavelength is selectively reflected in the planar arrangement state and appears to be colored red, blue, and green, respectively. Multi-color display is also possible by stacking liquid crystal layers of each color. In addition, by setting the selective reflection wavelength to, for example, an infrared region, it looks transparent. In the chiral nematic liquid crystal, the selective reflection wavelength can be adjusted by adjusting the helical pitch by adjusting the amount of the chiral agent added.

The liquid crystal exhibiting a cholesteric phase appears opaque by scattering incident light in a focal conic alignment state in which the helical axis is oriented in an irregular direction. As in the case where the selective reflection wavelength of the cholesteric liquid crystal is in the visible range,
When the helical pitch is short, scattering is reduced, and the helical axis is arranged substantially parallel to the substrate, so that a state close to being transparent can be obtained.

Therefore, by switching between the two states of the planar arrangement and the focal conic arrangement, a display such as selective reflection (planar arrangement) -transparent (focal conic arrangement), transparent (planar arrangement) -white turbidity (focal conic arrangement), or the like is performed. be able to. In addition, a method using a nematic liquid crystal alone, for example, two polarizing plates are arranged orthogonally to each other with a liquid crystal layer interposed therebetween, and light passing through the upper polarizing plate is subjected to the effect of the optical anisotropy Δn of the liquid crystal molecules to form the liquid crystal molecules. By rotating along the twist and passing it through the lower polarizing plate, it becomes brighter.On the other hand, when the electric field is applied to the liquid crystal layer and the liquid crystal molecules are untwisted, there is no effect of rotating the plane of polarization. The light can also be applied to a so-called TN method in which light is blocked by a lower polarizing plate and becomes dark.

[0046]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In each of the following examples, the reflectance was measured by measuring the spectral reflectance (Y value) using a reflection type spectrophotometer CM-1000 (manufactured by Minolta). The smaller the Y value, the more transparent. The contrast is given by (Y value in high reflectance state / Y value in low reflectance state). Example 1 A well-cleaned first glass substrate with an ITO electrode was
After dehydration baking at 0 ° C. for 30 minutes, a photoresist material made of a melamine resin (SP value: 10, negative type, manufactured by JSR) was spin-coated so as to form thick films of 5 μm, 12 μm, and 18 μm, respectively. Then, the coating film was
Prebaking at 00 ° C. for 5 minutes, providing a photomask having a plurality of openings so as to obtain a plurality of columnar structures on the coating film, and applying the photoresist material coating film through the photomask to an ultraviolet irradiation device. And exposed. Then 1
After exposure at 00 ° C. for 3 minutes, baking was performed and development was performed. Next, the substrate was washed with pure water and dried. Furthermore, post exposure and post baking at 100 ° C. for 5 minutes are performed.
A columnar structure was obtained.

The SP value of the photoresist material is determined by mixing it with an organic solvent of which the SP value is known in advance and visually determining whether it is compatible (maintains a transparent state) or incompatible (has cloudiness). And the SP value of the organic solvent in which the photoresist material was compatible. The same applies to the following embodiments. When the height of the columnar structure was measured with a film thickness meter, the film thickness was 5 μm, 12 μm, and 18 μm, respectively. It was confirmed that the height of the columnar structure obtained by the above steps was the same as the thickness of the photoresist material applied on the substrate.

Next, on the columnar structure on the first substrate,
A glass substrate with a second ITO electrode is covered with the electrode forming surface facing the columnar structure, and a sealing agent Photolec (manufactured by Sekisui Fine Chemical Co., Ltd.) containing spacers is used to seal and bond between the peripheral portions of the substrate. Then, an empty cell was obtained. Next, an ester-based nematic liquid crystal having an SP value of 7 (refractive index anisotropy Δn = 0.170, dielectric anisotropy Δε = 30, phase transition temperature to isotropic phase T _{N− I} = 100 ° C.) is placed in an empty cell. ) Was injected with a chiral nematic liquid crystal to which a chiral material (S-811, manufactured by Merck) was added. Liquid crystal in which the amount of the chiral material added is adjusted so as to have a selective reflection wavelength in the blue region is injected into an empty cell having a columnar structure of 5 μm, and selectively reflected in the green region into an empty cell having a columnar structure of 12 μm. Liquid crystal in which the addition amount of the chiral material is adjusted so as to have a wavelength is injected, and liquid crystal in which the addition amount of the chiral material is adjusted so as to have a selective reflection wavelength in the red region is injected into an empty cell having a columnar structure of 18 μm. Thus, a liquid crystal element was obtained.

When a relatively high pulse voltage was applied to these liquid crystal elements, the liquid crystal was in a planar state after removal of the pulse voltage, and displayed in blue, green and red, respectively. When a relatively low pulse voltage is applied to these liquid crystal elements,
After removing the pulse voltage, all became transparent. When a voltage was applied to each liquid crystal element and the device performance was measured, good performance was obtained as shown below. That is, for blue, the driving voltage is 30 V (focal conic arrangement) / 50
V (planar arrangement), contrast was 5.4, and reflectivity in the planar arrangement was 23%. Drive voltage is 3 in green
0 V (focal conic arrangement) / 60 V (planar arrangement), the contrast was 14.6, and the reflectance in the planar arrangement was 22%. For red, the drive voltage was 55 V (focal conic arrangement) / 100 V (planar arrangement), the contrast was 4, and the reflectance in the planar arrangement was 27%.

Further, on the resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angle is 6 ° for blue, 13 ° for green,
It was 12 ° in red. Example 2 Example 1 was the same as Example 1 except that a photoresist material (SP value 15, negative type, manufactured by JSR Corporation) made of a melamine-based resin was used instead of the photoresist material (SP value 10). In the same manner as in the above, each liquid crystal element capable of displaying blue, green and red was obtained.

When a voltage was applied to each liquid crystal element and the device performance was measured, good performance was obtained as shown below. That is, in blue, the driving voltage was 30 V (focal conic arrangement) / 55 V (planar arrangement), the contrast was 5.2, and the reflectance in the planar arrangement was 24%.
In green, the driving voltage is 30 V (focal conic arrangement) /
60V (planar arrangement), contrast was 15.3, and reflectivity in the planar arrangement was 23%. In red, the driving voltage was 50 V (focal conic arrangement) / 95 V (planar arrangement), the contrast was 4.5, and the reflectance in the planar arrangement was 28%.

Further, on the resist film obtained by performing the same process as above, but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angle is 5 ° for blue, 15 ° for green,
It was 11 ° in red. Example 3 Example 1 was the same as Example 1 except that a photoresist material (SP value 12, negative type, manufactured by JSR Corporation) made of a melamine-based resin was used instead of the photoresist material (SP value 10). In the same manner as in the above, each liquid crystal element capable of displaying blue, green and red was obtained.

When a voltage was applied to each liquid crystal element and the device performance was measured, good performance was obtained as shown below. That is, for blue, the driving voltage was 29 V (focal conic arrangement) / 52 V (planar arrangement), the contrast was 5.4, and the reflectance in the planar arrangement was 24%.
In green, the driving voltage is 30 V (focal conic arrangement) /
60V (planar arrangement), contrast was 14.9, and reflectance in the planar arrangement was 23%. In red, the driving voltage was 50 V (focal conic arrangement) / 100 V (planar arrangement), the contrast was 4.2, and the reflectance in the planar arrangement was 28%.

Also, on the resist film obtained by performing the same process as above but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angles are 5 ° for blue, 14 ° for green,
It was 13 ° in red. Example 4 Example 1 was the same as Example 1 except that a photoresist material (SP value 14, negative type, manufactured by JSR Corporation) composed of a melamine-based resin was used instead of the photoresist material (SP value 10). In the same manner as in the above, each liquid crystal element capable of displaying blue, green and red was obtained.

When a voltage was applied to each liquid crystal element and the device performance was measured, good performance was obtained as shown below. That is, for blue, the driving voltage was 30 V (focal conic arrangement) / 53 V (planar arrangement), the contrast was 5.3, and the reflectance in the planar arrangement was 23%.
In green, the driving voltage is 30 V (focal conic arrangement) /
59V (planar arrangement), contrast was 15.1, and reflectivity in the planar arrangement was 23%. In red, the driving voltage was 50 V (focal conic arrangement) / 98 V (planar arrangement), the contrast was 4.3, and the reflectance in the planar arrangement was 28%.

Further, on the resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angle is 5 ° for blue, 13 ° for green,
It was 12 ° in red. Example 5 A well-cleaned first glass substrate with an ITO electrode was heated in a drying oven at 80 ° C. for 15 minutes, then a polyimide alignment film was spin-coated, and heated at 80 ° C. for 5 minutes on a hot plate and dried. Heated in furnace at 180 ° C. for 2 hours.
The first substrate with the alignment film was dehydrated and baked at 200 ° C. for 30 minutes, and spin-coated with a photoresist material (SP value: 10, negative type, manufactured by JSR) made of a melamine resin. Next, the coating film is pre-baked at 100 ° C. for 5 minutes, and a photomask having a plurality of openings so as to obtain a plurality of columnar structures is provided on the coating film, and the photoresist material is applied through the photomask. The film was exposed using an ultraviolet irradiation device. Next, the film was baked after exposure at 100 ° C. for 3 minutes and developed. Next, the substrate was washed with pure water and dried. Further, post exposure and post baking at 100 ° C. for 5 minutes were performed to obtain a columnar structure. When the height of the columnar structure was measured with a film thickness meter, it was 7 μm.

Next, on the columnar structure on the first substrate,
Similarly, a second glass substrate having a polyimide alignment film formed on the ITO electrode formation surface is covered with the alignment film formation surface facing the columnar structure, and a sealing agent Photolec containing spacers (manufactured by Sekisui Fine Chemical Co., Ltd.) Was used to seal and adhere between the peripheral portions of the substrate to obtain empty cells. Next, a chiral nematic liquid crystal obtained by adding a chiral material to an ester-based nematic liquid crystal and having a selective reflection wavelength in a green region having an SP value of 7 was injected into the empty cell to obtain a liquid crystal element.

When a device performance was measured by applying a voltage to the liquid crystal element, the driving voltage was 60 V (focal conic arrangement) / 90 V (planar arrangement), the contrast was 8.1, and the reflectance in the planar arrangement was 27%. And good device characteristics were obtained. Further, the liquid crystal was dropped on a resist film obtained by performing the same process as above, but exposing the entire surface without using a photomask, and using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., CA-X). When the contact angle between the columnar structure and the liquid crystal was measured using the above method, it was 14 °. Example 6 A well-cleaned first glass substrate with an ITO electrode was
After dehydration baking at 0 ° C. for 30 minutes, a photoresist material (SP value: 10, negative type, manufactured by JSR) made of a melamine resin was spin-coated. Then, the coating film was
Pre-baking at 0 ° C. for 5 minutes, providing a photomask having a plurality of openings so as to obtain a plurality of columnar structures on the coating film, and applying the photoresist material coating film through the photomask to an ultraviolet irradiation device. And exposed. Then 10
After exposure at 0 ° C. for 3 minutes, the film was baked and developed. Next, the substrate was washed with pure water and dried. Further, post exposure and post baking at 100 ° C. for 5 minutes were performed to obtain a columnar structure. When the height of this columnar structure was measured, it was 7μ.
m.

Next, on the columnar structure on the first substrate,
An alignment film of a polyamic acid type was provided. This alignment film is formed by spray coating the alignment film material on the columnar structure,
It was formed by baking at 0 ° C. Also, the second ITO
The same alignment film was also provided on the electrode-formed surface of the glass substrate with electrodes, and the alignment film was put thereon so as to be aligned with the alignment film on the first electrode, and both alignment films were bonded at a temperature of 200 ° C. . Further, using a sealing agent Photolec containing spacers (manufactured by Sekisui Fine Chemical Co., Ltd.), the periphery of the substrate was sealed and bonded to obtain an empty cell.

A chiral nematic liquid crystal obtained by adding a chiral material to an ester-based nematic liquid crystal having an SP value of 7 and having a selective reflection wavelength in green was injected into the empty cell. When a device performance was measured by applying a voltage to this liquid crystal element, the drive voltage was 35 V (focal conic alignment) / 6.
Good device characteristics were obtained, with 5V (planar arrangement), contrast of 8, and reflectivity of 23% in the planar arrangement.

In addition, on a resist film obtained by performing the same process as above, but exposing the entire surface without using a photomask,
The liquid crystal was dropped and a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., CA
When the contact angle between the columnar structure and the liquid crystal was measured using -X), it was 16 °. Example 7 In Example 1, an ester nematic liquid crystal having an SP value of 7 (refractive index anisotropy Δn = 0.170, dielectric anisotropy Δε) was used in place of the chiral nematic liquid crystal having an SP value of 7.
= 30 and a phase transition temperature to an isotropic phase T _NI = 100 ° C), _except that a liquid crystal device was obtained in the same manner as in Example 1.

Polarizing plates perpendicular to each other were arranged above and below this liquid crystal element to form a TN type liquid crystal element. Then, when a voltage was applied to the liquid crystal element and the element characteristics were measured, a good device specification having a transmittance of 93% at a driving voltage of 0 V and a transmittance of 10% at a driving voltage of 2.3 V was obtained. Also,
The nematic liquid crystal is dropped on a resist film obtained by performing the same process as above but exposing the entire surface without using a photomask, and a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.)
The contact angle between the columnar structure and the liquid crystal was measured using, and was 13 °. Example 8 In Example 3, an ester nematic liquid crystal having an SP value of 7 (refractive index anisotropy Δn = 0.170, dielectric anisotropy Δε) was used in place of the chiral nematic liquid crystal having an SP value of 7.
= 30 and a phase transition temperature to an isotropic phase T _NI = 100 ° C), _except that a liquid crystal device was obtained in the same manner as in Example 3.

Polarizing plates orthogonal to each other were arranged above and below the liquid crystal element to form a TN type liquid crystal element. Then, when a voltage was applied to the liquid crystal element and the element characteristics were measured, a good device specification having a transmittance of 95% at a driving voltage of 0 V and a transmittance of 12% at a driving voltage of 2.3 V was obtained. Also,
The nematic liquid crystal is dropped on a resist film obtained by performing the same process as above but exposing the entire surface without using a photomask, and a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.)
The contact angle between the columnar structure and the liquid crystal was measured using, and was 16 °. Example 9 A well-cleaned first glass substrate with an ITO electrode was
After dehydration baking at 0 ° C. for 30 minutes, a photoresist material made of an acrylic resin (SP value 11, positive type, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated so as to form a thick film of 3 μm, 10 μm, and 19 μm, respectively. Next, the coating film is pre-baked at 110 ° C. for 3 minutes, and a photomask having a plurality of openings for obtaining a plurality of columnar structures is provided on the coating film, and the photoresist material is applied through the photomask. The film was exposed using an ultraviolet irradiation device and developed at room temperature. Then, after washing with pure water and drying,
Washed with 3% ammonium oxalate, washed with pure water and dried. Further, post exposure and post baking at 220 ° C. for 3 minutes were performed to obtain a columnar structure.

When the heights of the columnar structures were measured with a film thickness meter, the thicknesses were 3 μm, 10 μm, and 19 μm, respectively. It was confirmed that the height of the columnar structure obtained by the above steps was the same as the thickness of the photoresist material applied on the substrate. Next, a second glass substrate with an ITO electrode is placed on the columnar structure on the first substrate with the electrode forming surface facing the columnar structure, and a sealing agent Photolec containing spacers (Sekisui Fine Chemical Co., Ltd.) ) Was used to seal and bond between the peripheral portions of the substrate to obtain empty cells. Next, a chiral nematic liquid crystal having an SP value of 7 and a chiral material added to an ester nematic liquid crystal was injected into the empty cell. Liquid crystal in which the amount of the chiral material added is adjusted so as to have a selective reflection wavelength in the blue region is injected into an empty cell having a columnar structure of 3 μm, and selectively reflected in the green region into an empty cell having a columnar structure of 10 μm. Liquid crystal in which the addition amount of the chiral material is adjusted so as to have a wavelength is injected, and liquid crystal in which the addition amount of the chiral material is adjusted so as to have a selective reflection wavelength in the red region is injected into an empty cell having a columnar structure of 19 μm. Then, each liquid crystal element was obtained.

When the device performance was measured by applying a voltage to each liquid crystal element, good performance was obtained as shown below. That is, in blue, the driving voltage was 45 V (focal conic arrangement) / 70 V (planar arrangement), the contrast was 2.5, and the reflectance in the planar arrangement was 27%.
In green, the driving voltage is 40 V (focal conic arrangement) /
85V (planar arrangement), the contrast was 7.9, and the reflectance in the planar arrangement was 30%. In red, the driving voltage was 60 V (focal conic arrangement) / 115 V (planar arrangement), the contrast was 2.3, and the reflectance in the planar arrangement was 31%.

Also, on the resist film obtained by performing the same process as above, but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). Contact angle is 10 ° for blue and 12 for green
° and 16 ° in red. Example 10 The procedure of Example 9 was repeated except that a photoresist material (SP value 14, positive type, manufactured by Tokyo Ohka Kogyo Co., Ltd.) made of an acrylic resin was used instead of the photoresist material (SP value 11). In the same manner as in Example 9, each liquid crystal element capable of displaying blue, green, and red was obtained.

When a voltage was applied to each liquid crystal element to measure the device performance, good performance was obtained as shown below. That is, for blue, the driving voltage was 50 V (focal conic arrangement) / 80 V (planar arrangement), the contrast was 2.3, and the reflectance in the planar arrangement was 25%.
In green, the driving voltage is 45V (focal conic arrangement) /
90V (planar arrangement), the contrast was 7.6, and the reflectivity in the planar arrangement was 29%. For red, the drive voltage was 65 V (focal conic arrangement) / 125 V (planar arrangement), the contrast was 2.0, and the reflectivity in the planar arrangement was 29%.

Further, on a resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angle is 11 ° for blue and 13 for green
° and 17 ° in red. Example 11 In Example 1, a plastic substrate with an ITO electrode was used instead of the glass substrate with an ITO electrode.
Each liquid crystal element capable of displaying blue, green, and red was obtained in the same manner as in Example 1 except that dehydration baking of the substrate at 200 ° C. was not performed.

When the device performance was measured by applying a voltage to each liquid crystal element, good performance was obtained as shown below. That is, for blue, the driving voltage was 30 V (focal conic arrangement) / 50 V (planar arrangement), the contrast was 5.4, and the reflectance in the planar arrangement was 23%.
In green, the driving voltage is 30 V (focal conic arrangement) /
The voltage was 60 V (planar arrangement), the contrast was 14.6, and the reflectance in the planar arrangement was 22%. For red, the drive voltage was 55 V (focal conic arrangement) / 100 V (planar arrangement), the contrast was 4, and the reflectance in the planar arrangement was 27%.

Further, on the resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue, green, and red liquid crystals was dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angles are 9 ° for blue, 16 ° for green,
It was 15 ° in red. Example 12 A well-cleaned first glass substrate with an ITO electrode was
After dehydration baking at 0 ° C. for 30 minutes, a photoresist material made of a melamine resin (SP value: 10, negative type, manufactured by JSR) was spin-coated so as to form thick films of 5 μm, 12 μm, and 18 μm, respectively. Then, the coating film was
Prebaking at 00 ° C. for 5 minutes, providing a photomask having a plurality of openings so as to obtain a plurality of columnar structures on the coating film, and applying the photoresist material coating film through the photomask to an ultraviolet irradiation device. And exposed. Then 1
After exposure at 00 ° C. for 3 minutes, baking was performed and development was performed. Next, the substrate was washed with pure water and dried. Furthermore, post exposure and post baking at 100 ° C. for 5 minutes are performed.
A columnar structure was obtained.

Then, a 5 μm diameter, 12 μm
A second glass substrate with an ITO electrode on which spacers of m and 18 μm are scattered is prepared, and a second glass substrate with an ITO electrode is provided on the columnar structure on the first substrate with an electrode forming surface (spacer scatter surface). It was covered toward the columnar structure. Furthermore, the periphery of the substrate is sealed with a sealing agent XN-21-S (manufactured by Mitsui Chemicals, Inc.) containing a spacer, and heated at 180 ° C. for 2 hours while pressing with a jig from both sides of the substrate. The sealing agent was cured to bond the two substrates together to obtain an empty cell. At this time, when the cell gap was measured using a film thickness meter,
They were 5 μm, 12 μm and 18 μm, respectively.

Next, an ester nematic liquid crystal having an SP value of 7 (refractive index anisotropy Δn = 0.170, dielectric anisotropy Δε = 30, phase transition temperature to isotropic phase T _NI = 7) was placed in an empty cell.
(100 ° C) chiral material (S-811, manufactured by Merck)
The chiral nematic liquid crystal to which was added was injected. 5μ
An empty cell having a columnar structure of m is injected with a liquid crystal in which the amount of a chiral material added is adjusted so as to have a selective reflection wavelength in a blue region, and an empty cell having a columnar structure of 12 μm is selectively reflected in a green region. Liquid crystal in which the addition amount of the chiral material is adjusted so as to have a wavelength is injected, and liquid crystal in which the addition amount of the chiral material is adjusted so as to have a selective reflection wavelength in the red region is injected into an empty cell having a columnar structure of 18 μm. Thus, a liquid crystal element was obtained.

When a voltage was applied to each liquid crystal element and the device performance was measured, good performance was obtained as shown below. That is, in blue, the driving voltage was 30 V (focal conic arrangement) / 50 V (planar arrangement), the contrast was 5.3, and the reflectance in the planar arrangement was 22%.
In green, the driving voltage is 30 V (focal conic arrangement) /
The voltage was 60 V (planar arrangement), the contrast was 14.5, and the reflectance in the planar arrangement was 22%. In red, the driving voltage was 50 V (focal conic arrangement) / 95 V (planar arrangement), the contrast was 3.9, and the reflectance in the planar arrangement was 26%.

In the twelfth embodiment, a spacer having the same diameter as the thickness of the photoresist material coating film in the first embodiment is used, but the height of the columnar structure formed in the first embodiment is reduced. The same cell gap was obtained. The driving voltage, contrast, and reflectivity in the planar arrangement of this liquid crystal element were substantially the same as those of the liquid crystal element of Example 1, respectively. From these facts, it is understood that, even when the columnar structure is formed and the spacer is used in combination, the device characteristics are not affected, and a liquid crystal layer having a desired thickness can be obtained as in the case where the spacer is not used. . Comparative Example 1 A first glass substrate with a well-cleaned ITO electrode
After dehydration baking at 0 ° C. for 30 minutes, a photoresist material made of an acrylic resin (SP value: 8, negative type, manufactured by JSR Corporation) was spin-coated to form thick films of 5 μm, 12 μm, and 18 μm, respectively. Then, the coating was applied to 9
Pre-baking at 0 ° C. for 5 minutes, providing a photomask having a plurality of openings so as to obtain a plurality of columnar structures on the coating film, and applying the photoresist material coating film through the photomask to an ultraviolet irradiation device. Exposure and development.
Next, the substrate was washed with pure water and dried. Furthermore, post exposure and post-baking at 130 ° C. for 5 minutes were performed to obtain a columnar structure.

When the heights of the columnar structures were measured with a film thickness meter, they were 5 μm, 12 μm, and 18 μm, respectively. Next, the second I-type semiconductor substrate is placed on the columnar structure on the first substrate.
A glass substrate with a TO electrode is covered with the electrode forming surface facing the columnar structure, and the periphery of the substrate is sealed and bonded using a sealing agent Photolec containing spacers (manufactured by Sekisui Fine Chemical Co., Ltd.). I got a cell. Next, SP into the empty cell
A chiral nematic liquid crystal having a value of 7 and a chiral material added to an ester-based nematic liquid crystal was injected. 5 μm
Liquid crystal in which the amount of the chiral material added is adjusted so as to have a selective reflection wavelength in the blue region is injected into the empty cell having the columnar structure, and the selective reflection wavelength is applied to the green region into the empty cell having the 12 μm columnar structure. The liquid crystal in which the added amount of the chiral material was adjusted so as to have the above was injected to obtain a liquid crystal element. In addition,
An empty cell having a columnar structure of 18 μm was not used.

When the device performance was measured by applying a voltage to each liquid crystal element, the drive voltage for blue was 25 V (focal conic arrangement) / 65 V (planar arrangement), the contrast was 1.3, and the reflectance in the planar arrangement was 28. %
The contrast was very low. In green, the driving voltage was 40 V (focal conic arrangement) / 90 V (planar arrangement), the contrast was 5.9, the reflectivity in the planar arrangement was 18%, and the reflectivity in the planar state was very low.

A chiral nematic liquid crystal having an SP value of 7 similar to that described above and having a chiral material added to an ester nematic liquid crystal (selective reflection wavelength in green) was provided between the columnar structures having a height of 7 μm obtained in the same manner as described above. Was left for 2 hours, and the liquid crystal was washed away with n-hexane and dried. When a sample obtained by depositing gold on the columnar structure was observed using a scanning electron microscope (SEM), the outer shape was broken and the height was reduced.

Further, on the resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue and green liquid crystals and the separately prepared red liquid crystal were dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angles were 21 ° for blue, 17 ° for green, and 25 ° for red. Comparative Example 2 A first glass substrate with a well-cleaned ITO electrode
After dehydration baking at 0 ° C. for 30 minutes, a photoresist material (SP value: 7, negative type, manufactured by JSR) made of an acrylic resin was spin-coated so as to have a film thickness of 5 μm, 12 μm, and 18 μm. Next, the coating film is treated at 80 ° C. for 5
Pre-baking for a minute, providing a photomask having a plurality of openings such that a plurality of columnar structures can be obtained on the coating film, and exposing the photoresist material coating film through the photomask using an ultraviolet irradiation device. And development. Next, the substrate was washed with pure water and dried. Further, post exposure and post baking at 110 ° C. for 5 minutes were performed to obtain a columnar structure.

When the heights of the columnar structures were measured with a film thickness meter, the thicknesses were 5 μm, 12 μm, and 18 μm, respectively. Next, the second I-type semiconductor substrate is placed on the columnar structure on the first substrate.
A glass substrate with a TO electrode is covered with the electrode forming surface facing the columnar structure, and the periphery of the substrate is sealed and bonded using a sealing agent Photolec containing spacers (manufactured by Sekisui Fine Chemical Co., Ltd.). I got a cell. Next, SP into the empty cell
A chiral nematic liquid crystal having a value of 7 and a chiral material added to an ester-based nematic liquid crystal was injected. 5 μm
Liquid crystal in which the amount of the chiral material added is adjusted so as to have a selective reflection wavelength in the blue region is injected into the empty cell having the columnar structure, and the selective reflection wavelength is applied to the green region into the empty cell having the 12 μm columnar structure. The liquid crystal in which the added amount of the chiral material was adjusted so as to have the above was injected to obtain a liquid crystal element. In addition,
An empty cell having a columnar structure of 18 μm was not used.

When the device performance was measured by applying a voltage to each liquid crystal element, the drive voltage for blue was 28 V (focal conic arrangement) / 67 V (planar arrangement), the contrast was 1.1, and the reflectance in the planar arrangement was 27. %
The contrast was very low. In green, the driving voltage was 38 V (focal conic arrangement) / 88 V (planar arrangement), the contrast was 5.7, the reflectivity in the planar arrangement was 17%, and the reflectivity in the planar state was extremely low.

The height of 12 μm obtained in the same manner as above
Chiral nematic liquid crystal (having a selective reflection wavelength in green), in which an chiral material is added to an ester nematic liquid crystal having an SP value of 7 as described above, between columnar structures of
And left for 2 hours, then the liquid crystal was washed off with n-hexane and dried. When a sample obtained by depositing gold on the columnar structure was observed using a scanning electron microscope (SEM), it was found that the dissolution had progressed, the outer shape had been significantly collapsed, and the height had decreased.

Also, on the resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue and green liquid crystals and the separately prepared red liquid crystal were dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Interface Science Co., Ltd.). The contact angles were 23 ° for blue, 19 ° for green, and 28 ° for red. Comparative Example 3 A first glass substrate with a well-cleaned ITO electrode
Dehydrated and baked at 0 ° C for 30 minutes, and cyclized polyisoprene-based photoresist (SP value 7, negative type, OMR manufactured by Tokyo Ohka)
-83) was spin-coated to a thickness of 7 μm, exposed using a photomask, and developed to obtain a columnar structure. Between the 7 μm columnar structures, the same S
After filling with a chiral nematic liquid crystal (having a selected wavelength for green) obtained by adding a chiral material to an ester type nematic liquid crystal having a P value of 7, the liquid crystal was washed with n-hexane and dried. When a sample obtained by depositing gold on the columnar structure was observed using a scanning electron microscope (SEM), the outer shape was broken and the height was reduced.

Further, on the resist film obtained by performing the same process as described above but exposing the entire surface without using a photomask,
Each of the blue and green liquid crystals and the separately adjusted red liquid crystal were dropped, and the contact angle between the columnar structure and each liquid crystal was measured using a contact angle meter (CA-X, manufactured by Kyowa Sea Surface Science Co., Ltd.). The contact angles were 25 ° for blue, 19 ° for green, and 27 ° for red. As a result, the liquid crystal devices obtained by Examples 1 to 12 of the present invention in which the SP value of the photoresist material was in the range of 10 to 15 were S
It can be seen that when used in combination with a liquid crystal having a P value in the range of 8 or less, all exhibited good contrast and reflectance. On the other hand, SP of photoresist material
It can be seen that each of the liquid crystal devices obtained in Comparative Examples 1 and 2 having a value of 7 or 8 did not provide sufficient contrast and reflectance when used in combination with a liquid crystal having an SP value of 7.

Since the height of the finally obtained columnar structure was the same as the thickness of the photoresist material film applied on the substrate, the method of the present invention using the photoresist material did not require the use of spacers. However, it can be seen that a columnar structure having a desired height can be easily formed. It is also understood that a liquid crystal element having similar good device characteristics can be obtained by forming a columnar structure made of photoresist and using a spacer.

[0085]

As described above, according to the present invention, at least one is a liquid crystal element in which liquid crystal is sealed between a pair of transparent substrates, and is not affected by the hardness of the substrate as compared with the conventional element. In addition, it is possible to provide a liquid crystal element in which the thickness of the liquid crystal layer can be kept constant over a long period of time, whereby a desired contrast and reflectance can be stably obtained, and a simple manufacturing method thereof.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a liquid crystal element according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a cross section of a liquid crystal element according to another embodiment of the present invention.

FIG. 3 is a diagram showing a cross section of a liquid crystal element according to still another embodiment of the present invention.

FIG. 4 is a diagram showing a cross section of a liquid crystal element according to still another embodiment of the present invention.

FIG. 5 is a view showing a cross section of a liquid crystal element according to still another embodiment of the present invention.

FIG. 6 is a diagram showing a cross section of a liquid crystal element according to still another embodiment of the present invention.

[Explanation of symbols]

 1a, 1b Substrate with electrodes 2 Columnar structure 3 Liquid crystal 4 Sealing wall 5 Electric insulating film 6 Alignment film

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideaki Ueda 2-13-13 Azuchicho, Chuo-ku, Osaka-shi Osaka International Building Minolta Co., Ltd. F term (reference) 2H089 LA09 MA04X NA14 PA01 QA14 RA04 SA17

Claims (20)

[Claims] A first and a second substrate, at least one of which is transparent, opposed to each other, a plurality of columnar structures provided between the substrates, and a space between the columnar structures between the substrates. A liquid crystal element comprising: a sealed liquid crystal; wherein the columnar structure is formed of a polymer substance obtained from a material having an SP value of 10 to 15. 2. The liquid crystal device according to claim 1, wherein said polymer substance is a photoresist. 3. The liquid crystal device according to claim 1, wherein the height of the columnar structure formed of the polymer material is 3 μm to 20 μm. 4. The liquid crystal device according to claim 1, wherein the height of the columnar structure formed of the polymer material is 5 μm to 15 μm. 5. The device according to claim 1, wherein each of the first and second substrates has an electrode, and the two substrates are arranged to face each other such that the electrodes face each other. Liquid crystal element. 6. The liquid crystal device according to claim 1, wherein at least one of the first and second substrates disposed on the liquid crystal device observation side is a transparent glass plate or a transparent synthetic resin film. 7. The liquid crystal device according to claim 1, wherein a peripheral portion between the two substrates is sealed with a sealant. 8. The columnar structure and the first or (and)
The liquid crystal device according to claim 1, wherein an electric insulating film is formed between the liquid crystal device and the second substrate. 9. The columnar structure and the first or (and)
9. The liquid crystal device according to claim 1, wherein an alignment film is formed between the liquid crystal device and the second substrate. 10. An SP value of 1 on one surface of the first substrate.
A photoresist material application step of applying a photoresist material of 0 to 15 with a predetermined thickness; an exposure step of performing an exposure treatment on the coating film of the photoresist material in a predetermined exposure pattern; and after the exposure step, developing the coating film. A developing step of performing processing to obtain a plurality of columnar structures corresponding to the exposure pattern; and covering the first substrate with a second substrate over the columnar structure.
A method for manufacturing a liquid crystal element, comprising: a substrate superimposing step of superposing over a substrate; and a liquid crystal disposing step of disposing a liquid crystal between the columnar structures. 11. In the photoresist material applying step,
The method according to claim 10, wherein the photoresist material is applied to a thickness of 3 μm to 20 μm. 12. In the photoresist material applying step,
The method for manufacturing a liquid crystal element according to claim 10, wherein the photoresist material is applied in a thickness of 5m to 15m. 13. The method according to claim 10, wherein a pre-baking process is performed on the photoresist material coating before the exposing step.
3. The method for manufacturing a liquid crystal element according to any one of 2. 14. After the exposing step and before the developing step,
14. The method for manufacturing a liquid crystal device according to claim 10, wherein the coating film is subjected to a baking treatment after exposure. 15. The post-exposure process and the post-baking process performed on the columnar structure obtained by the developing process after the developing process and before the substrate overlapping process and the liquid crystal disposing process. 3. The method for producing a liquid crystal element according to item 1. 16. The method according to claim 16, wherein the first and second substrates each have an electrode. In the photoresist material applying step, a photoresist material is applied on an electrode forming surface of the first substrate, and the substrate overlapping step is performed. The liquid crystal according to any one of claims 10 to 15, wherein the second substrate is placed on the second substrate so that the electrodes face each other by covering the second substrate with its electrode formation surface facing the columnar structure. Device manufacturing method. 17. A transparent glass plate or a transparent synthetic resin film is used as at least one of the first and second substrates disposed on the liquid crystal element observation side.
7. The method for manufacturing a liquid crystal element according to any one of 6. 18. The method for manufacturing a liquid crystal element according to claim 10, further comprising a step of sealing a peripheral portion between the two substrates with a sealing agent. 19. The liquid crystal device according to claim 10, further comprising a step of forming an alignment film between said columnar structure and said first and / or second substrate. 20. The liquid crystal device according to claim 10, further comprising a step of forming an electrically insulating film between said columnar structure and said first and / or second substrate. Method.